DRILLING FOR PLACER GOLD



HARRON, RICKARD & MeGONE

SOLE AGENTS
AN FRANCISCO




Work continues in spite of snow



DRILLING FOR
PLACER GOLD



^KEYSTONE,



KEYSTONE DRILLER COMPANY
BEAVER FALLS, PENNA.




A deep hole in the High Sierras, California



CONTENTS

PART I PROSPECTING FOR PLACER GOLD WITH
THE KEYSTONE DRILL

BY WALTER H. GARDNER
Chapter 1 The Advantages of the Keystone Drill Page 11

Keystone drills have confidence of engineers. Wide range of use. Keystone
results given preference. Prospecting with shafts. Open cuts. Small hand-
drills. Keystone drill fits needs of engineer. Incident of Keystone usefulness.
Use of Keystone with operating dredges. Summary of Keystone advantages.

Chapter 2 Proper Drilling Methods Page 20

The crew. The Operator. The Fanner. The Fireman and the Waterbuck.
Four-man crew. Selection of machine. Fuels. Extra equipment. Packing
and shipping. Drive pipe, care and kind. Drive pipe, longer lengths.
Drive pipe, inspection. Moving drill. Setting up drill. Starting the hole.
Use of water. Drilling tight ground. Drilling loose ground. Use of jars.
Pumping. Checking Volume of material pumped. Driving. Finishing
hole. Pulling pipe. Panning. Tin prospecting. Platinum. Fire assays
improper. Precautions to be observed. Frozen ground. Unusual condi-
tions.

Chapter 3 Laying out the Ground and Estimating the

Values Page 44

Survey. What map should show. Plotting drill holes. Exploration with
drill. Laying out holes in stream deposit. "Blanket" deposits. Treatment
of amalgam. Determining fineness of gold. Value of milligiam of gold.
Calculation of cubic contents of drill-hole. Compensation for excessive cores.
Other constants in common use. Constant of .3333. Keystone constant of
.27. Reasons for the Keystone constant. No one constant invariably proper.
Combining value of various holes. Principle of evaluation. Calculation when
holes are spaced equidistantly. Other methods. "High Holes". Calculation
of stream channel values. Summary of calculation methods. What report
should cover.

Chapter 4 Reliability of Keystone Samplings Page 65

Keystone estimates now checked. Agreement on Oregon property. Check
on a California property. Another check from large acreage. Check from
small dredge operations. Example from operations of Natomas Cons, of Cali-
fornia. Montana property. Tabulation of available comparisons. Ac-
curate prospecting possible. How different conditions affect accuracy. Sum-
mary. Conclusion. Keystone creek placers. Plates "B", "C", "D", "E",
-F", "G", "H", "I", "J". Field log.

PART II AUTHORITATIVE ARTICLES ON
MINERAL PROSPECTING

The Prospecting and Valuing of Dredging Ground Page 88

by Norman C. Stines.

Laying off the ground. Operation of drilling the hole. Treatment of material
from the hole. The log book. Tables "1", "2". Calculating values. Final
calculations. Value of tests. Accuracy of the tests.



562."



CONTENTS Continued

Prospecting for Copper with Churn Drills Page 111

by F. S. Pheby.

Blasting Tight Placers Before Dredging Page 117

by Oliver B. Finn.

PART III MINERAL PROSPECTING MACHINERY
Mineral Prospecting Machinery Page 124

by R. M. Downie.

Core drills. Things which cannot be done' with a revolving core drill. What

cannot be done with Keystone drills.

Directions for the Operation of Keystone Machines and Use
of Accompanying Appliances Page 135

by R. M. Downie.

Moving and setting up. To string the drilling tools. Keystone cut drive
pipe. The drive pipe. Exploring from a float or flat boat. Driving the pipe.
Dressing the drilling bits. Caution. Pulling the pipe. Pipe pulling ring.

The Science of Zinc and Lead Prospecting with the Churn
Drill Page 171

by R. M. Downie.

Two Prime Requisites in a Prospecting Drill: Page 173

A Long Quick Stroke. A Vacuum Sludge Pump.

Quick stroke how obtained. Tendency of drillings to settle on bottom.
Trituration of drillings by slow motion drills. How to prevent drillings from
settling on the bottom. Keystone drill travel 360 feet per minute. A sim-
ple experiment. Another simple test. An incidental advantage of this
quick stroke. The suction sludge bucket. Still another test. False assays
caused by imperfectly cleaning out the hole. Keystone vacuum sand or sludge
pump. Examination of the sludge.

Drilling Costs in Potash Prospecting Page 183

by E. E. Free.

Cost of data of prospect drilling.

Successful Salting of Alluvials Page 188

by C. S. Haley.

Preliminary examination of alluvials. An unsuccessful attempt. Keystone

and Empire drilling. Drill sampling. Field log. Record of formation.



PAT i

PLACER



PROSPECTING
FOR PLACER GOLD WITH

THE
KEYSTONE DRILL

^^^^ T3ADE HACK. ^^H

.KEYSTONE,



COMPILED BY

WALTER H. GARDNER

And after being critically reviewed by the original designer
of this process and compared with the findings of a wide
circle of authentic and practical engineers who have used
the process, it is

PUBLISHED BY

KEYSTONE DRILLER COMPANY

Beaver Falls, Pennsylvania



DEDICATION

This Manual of Information for the Placer
Engineer is dedicated to the hardy men who have
carried the Keystone to the edges of the world;
who have cleared a path for it with machete
through the matted jungles; who have forgotten
frost-bitten fingers in Alaskan Tundras to finish
"one more hole"; who have lived and toiled in
far lands and outlying camps that they might
reveal new sources of treasure and open new
fields of human endeavor.



PREFACE



"The chum drill is, however, rtie besfr device, gnownfor prp*pe^tinR
ground having the necessary condition* Sot gQld dredging.-.'./. .-. J ,?. t .-

Engineering and Mining Journal

The Keystone Drill, as universally used, is not an instru-
ment of precision. Gold particles are not distributed with
mathematical symmetry. One drill hole to an acre in
ground that is 50 feet in depth only yields for examination
Hw.ooo part of the whole! Ordinary common sense and care
on the part of the operator and panner are sufficient to insure
acceptable field work. Meticulous precision or elaborate
core measurements are generally absurd.

For after the depths have been recorded and the gold
weighed, there comes the calculation of the values of
precious metal in great blocks of gravel. There is no fixed
formula. The experienced Engineer, to whom such work
should be entrusted, will compensate for high variations, for
loose and swelling ground, for sand and clay, for rusty gold
and his calculations will of necessity contain approxima-
tions that eclipse minor errors of the field and nullify minute
measurements .

Indeed, field work with the Keystone Drill need not be
conducted by men of profound skill. Just so the work is
done in a consistent manner under the occasional eye of a
competent engineer; just so the results are interpreted in
the light of experience then will the final figures carry the
full weight of authority.

There is no mystery about field work and should there
be, the following pages will clarify the mode of procedure.



10 DRILLING FOR PLACER GOLD

But there can be no standard of practice in interpreting the
drill rettjrnst-thi&bcto^jcan here only serve as a manual of
suggestions 1 and reminders "to the experienced engineer.

And, &rei -is herein CQn:gaine.cl a review of a generation of
Keystone* use in the light of the actual recovery from subse-
quent mining operations. Hitherto unpublished tables are
offered for the files of all interested in the exploration for
placer gold.

May you find this little book worthy of preservation !

THE AUTHOR.



CHAPTER I

THE ADVANTAGES OF THE
KEYSTONE DRILL

KEYSTONE DRILLS HAVE CONFIDENCE
OF ENGINEERS

To " Keystone" a gold dredging field is to "prospect" it!
So closely has the Keystone Drill identified itself with the
examination and calibration of auriferous gravels that its
very name has grown into the jargon of the Engineer as a
synonym of thorough and conscientious exploration. For
the past twenty-five years have seen extensive areas of river
gravels accepted for exploitation or cast into the discard on
the strength of no other information than that revealed by
the Keystone Drill in competent hands. With a serene con-
fidence in its reliability, men have invested hundreds of thou-
sands of dollars in the purchase of land and dredge machin-
ery or accepted an unfavorable verdict without a question.

WIDE RANGE OF USE

The Keystone Drill was first used for the determination
of gold values in a placer deposit in Idaho, in the spring of
1898. Since that time many hundreds of drills have been
shipped to all parts of the world and used in the testing of
bench and bottom land ; of old channels ; of the bars of live
streams; of lake and river bed. It has clattered in the
depths of the Columbian jungles where it paved the way for
the Nechi and Pato dredges ; it has probed the frozen gravels

11



12 DRILLING FOR PLACER GOLD




The Canadian Klondyke Mining Company used KEYSTONE DRILLS in their
extensive exploration work



DRILLING FOR PLACER GOLD 13

of Alaska and Siberia ; it has charted the wide areas of the
Oroville, Yuba and Natoma districts of California; it has
explored innumerable of the lesser streams of Oregon and
Montana, of the Philippines and the Malay States. It has
sought for gold; for platinum; for diamonds and for tin.
It has been transported under its own power; by horses;
on the backs of mules ; on snow-sleds ; in crude dug-outs
even on the backs of human carriers. Sometimes a half
dozen machines have been purchased and used to hasten the
work on a promising property there were at one time more
than 40 Keystone Drills operating simultaneously on the prop-
erty of the Lenskoi Mines. It has been used to determine the
presence or absence of precious metals ; it has been used to
carefully appraise the contents of whole tracts; it has lo-
cated limits of dredging possibilities both as to values,
depths and bedrock reefs. It has proved that its results are
the best index to dredging possibilities. And it has estab-
lished a reputation for sturdiness and reliability that few
machines enjoy.

KEYSTONE RESULTS GIVEN PREFERENCE

The Engineer who faces the task of correctly determining
the recoverable gold content of a placer field will ordinarily
have several alternatives of procedure. He may put down
shafts. Open cuts or exposed walls may give access to the
various strata. Ke may depend on a small and flimsy
"hand-drill." Or he may elect to do a thorough and ac-
curate exploration with a Keystone Drill. We briefly re-
view the various shortcomings and advantages of these
methods:



14 DRILLING FOR PLACER GOLD

PROSPECTING WITH SHAFTS

Sub-surface waters usually prevent extending a shaft to
bedrock. Uneven and improperly completed shafts do not
yield reliable data. The same inaccuracy attends the at-
tempt to sink a shaft below water level by the use of pumps
or other appliances. The inflow of water will carry values.
To be sure, if water did not interfere, a property might be
thoroughly prospected by shafts and by shafts alone but at
an unnecessarily high cost. And while the final data would
of course be accurate, it would, despite the greater size of
the samples, be little more authoritative than the Keystone
evaluations. So the Keystone Drill holes, miniature shafts
as they are, are today recognized as preferable from the
standpoint of the time and money that they save and as
accurate to nearly the same degree. But the careful Engi-
neer will usually check the operations of his Keystone with
one or more shafts to bedrock if possible and at least to
water-level. He sinks the shaft around one of the early
drill-holes. It gives him a better visualization of the strata
that the drill has already indicated it yields sufficient gold
to obtain a test as to the nature and purity of the particles
it supplies some data for the decision as to the proper "con-
stant" to be employed in his later calculations. And it also
more surely indicates the exact level of the sub -surface
water; it reveals something of the configuration of the bed-
rock; it more clearly tells of clay streaks and buried bould-
ers. But the experienced Engineer will rarely waste time
and energy on more than one such check shaft.

OPEN CUTS

A thorough exploration of a placer field will often dis-



DRILLING FOR PLACER GOLD 15

cover open cuts, old shafts, exposed banks and other oppor-
tunities to cross-cut the gravels to some depth. But such
exploration can seldom be more than casual and is either
merely supplementary or in advance of the determination
to drill thoroughly. For the random nature of such oppor-
tunities does not permit the systematic operations that alone
carry the assurance of accuracy.

SMALL HAND-DRILLS

Standard equipment for use with the Keystone Drill is
Extra Heavy Pipe 6 inches in diameter. It is generally held
that a smaller sample cannot be error-free. Two and a
quarter times as much material is recovered for examination
from the Keystone Drill holes as from a 4-inch pipe. While
there have been cases where the exigencies of transportation
seemed to encourage the lighter machine, and while it may
be permissable for preliminary work, it is of record that few
dredges have been purchased without adequate Keystone
results as the basis for the confidence of the investors. In-
deed, it has become almost an axiom that capital will not be
attracted to a placer field unless it has been thoroughly
"Keystoned"! Nor can the "hand-drill" cope with condi-
tions of hard ground. Dredge operators say that they can
work any gravel that can be broken by a man with a pick
and the operations at Natoma, California, certainly prove
the truth of this contention. But it requires a sturdy ma-
chine to probe such compact gravels heavy enough to
scorn the boulders that are inevitably encountered. The
Keystone Drill is of as light a design as may be confidently
entrusted to test with truth and accuracy the average de-
posit of auriferous or value bearing gravels.



16 DRILLING FOR PLACER GOLD




DRILLING FOR PLACER GOLD 17



KEYSTONE DRILL FITS NEEDS OF ENGINEER

The Engineer who wishes his work to carry the full flavor
of accuracy or the promoter or property owner who wishes
to collect data that will command the respect and belief of
others will not be satisfied with any but Keystone Drill re-
turns. Nor is the Keystone so heavy as to be difficult to
transport or to operate. Quite the contrary. The Key-
stone No. 1, with the boiler sectionalized, may be trans-
ported by pack-train. The Keystone No. 3, the standard
model for placer prospecting, is designed for speedy moving
and "setting up"; for the rapid drilling of holes that are but
rarely more than 60 feet in depth ; for hard work far afield
from machine-shop and organized repair facilities in short,
for the peculiar and arduous work of the pioneer Placer
Engineer!

INCIDENT OF KEYSTONE USEFULNESS

There is on record an example of the untrustworthiness of
shafts when they do not go to bedrock. One property was
once prospected to the depth of about ten feet when water
was encountered. These shafts revealed promising values
which had only to be maintained to a reasonable depth to
make an attractive dredging proposition. Indeed, so gratify-
ing were the returns that a company was formed and stock
sold. But cautious capital wisely demanded that the ground
be Keystoned and it was discovered that the lower gravels
were absolutely barren ! It seemed that an old and filled-up
lake bed, or settling basin, had been covered in recent times
with an all too thin layer of auriferous gravel. Here the
Keystone saved a very considerable sum of money for some
one ! Most Engineers prefer, if conditions at all permit, to



18 DRILLING FOR PLACER GOLD

rely on a Keystone even for preliminary work. It is dis-
concerting to arrive at a property after a long trip with noth-
ing more adequate than a "hand-drill" for equipment and
find ground that is too hard for it to attack and containing
too much water for shaft sinking !

USE OF KEYSTONE WITH OPERATING DREDGES

There is yet another angle to the situation. In the event
that preliminary work prompts a complete campaign of
evaluation, the Keystone is absolutely necessary. And when
the dredge is finally completed and at work, the Keystone
has not outlived its usefulness. Modern practice suggests
the continued use of the drill in front of the dredge, blasting
hard ground, determining the boundaries of barren areas,
charting the "pay-streak", seeking out reefs of hard bedrock,
tracing the sub-surface bench line, even forecasting the cur-
rent dredge returns. A large dredging company now follow
this practice, for, as they say, "There is nothing more foolish
or expensive than to prospect with a dredge!"

SUMMARY OF KEYSTONE ADVANTAGES

Here, then, are many reasons why a property under ex-
amination for its gold content should be Keystoned at as
early a date as may be possible

1. Keystone Drills are not too heavy to transport to
properties that are at all accessible.

2. Keystone Drills are able to cope with severe conditions
of deep bedrock, boulders and hard or frozen gravels.

3. Keystone Drills achieve very nearly the accuracy of
shaft work at the cost of less money and time.



DRILLING FOR PLACER GOLD 19

4. Keystone Drill returns command confidence and re-
spect. Their use adds weight to any report on a placer
property.

5. Keystone Drills are practically certain to be specified
on the final examination it is a matter of economy and
efficiency to use them even for preliminary work.

6. Keystone Drills do not outlive their usefulness with
the passing of the period of exploration.



CHAPTER II
PROPER DRILLING METHODS

THE GREW

Efficient operation of the Keystone Drill will in most cases
require a crew of three men the drill-operator, the panner
and a fireman. Usually a man with a team is necessary to
bring water and fuel as well as to aid in moving. Sometimes
the Engineer in charge will prefer to perform most of the
duties of a panner; sometimes, with oil-burning equipment,
one man may be eliminated.

THE OPERATOR

The man who actually runs the drill should be expe-
rienced. On him largely depends the accuracy and certainly
the expedition of the work. He should be capable of the re-
pair, replacement and bit-sharpening which must all be
sometimes conducted under the difficulties of limited con-
veniences afar from shop and machine equipment. The
Engineer will largely be occupied with exploration, survey-
ing, securing supplies, correspondence and manifold duties
his drill-operator should be a dependable lieutenant and a
resourceful mechanic.

THE PANNER

The panner, also, should be an experienced, discreet and
trustworthy man. His duties are to keep the records, check
the core, collect the recovered gravels and slimes, clean up
the sluice-box and make a full report to his superior on all
drilling operations. He is often asked to supplement the

20



DRILLING FOR PLACER GOLD 21

operator's pipe and rope measurements with an independent
check of his own. But the ideal man will do more than that
he will turn a willing hand to whatever chore presents it-
self, for he will have unoccupied moments. It is of impor-
tance that he be provided with shade in hot weather and
shelter and warmth in cold; otherwise his work can not be
kept free from variables incidental to cold and discomfort
and can not be prosecuted with full accuracy it being
unavoidable that his hands be in water much of the time.

THE FIREMAN AND THE WATER-BUCK

The work of keeping up steam and driving the team may
be entrusted to such labor as can be secured in the field of
operations. Ordinarily such men need not be skilled to any
degree but the very nature of prospecting work suggests
that there be some assurance of the loyalty and discretion of
every employee. The fireman should be required to start
his work on each shift in such season that a full head of steam
will be available upon the arrival of the rest of the crew.

FOUR-MAN GREW

In the extensive operations of one large company, the em-
ployment of a fourth man has been found a justifiable ex-
pense. With such a crew it becomes the duty of the fireman
to care for the fuel, water and lubrication; to act as mechan-
ical inspector, keeping all bolts tight ; and to keep a full head
of steam. The fourth man, or "helper", acts as assistant to
both panner and operator ; cleans casing threads ; prepares
roads in advance of moving ; runs needful errands, and in
general serves to keep lost time at a minimum.



22 D R I L L I NG FOR PLACER GOLD




DRILLING FOR PLACER GOLD 23

SELECTION OF MACHINE

For these many years the Keystone No. 3 Traction has
been the favored Model for placer prospecting. It is amply
powerful for all depths and all gravels likely to be encount-
ered. The friction-hoist is to be preferred. The No. 3
Non-Traction may be used, of course, but the traction ma-
chine soon earns back in saved time its somewhat greater
cost. Where transportation into regions difficult of access
must be provided, the lighter Keystone No. 1, with its boiler
sectionalized, may be carried in by pack-train. On those
rare occasions when the holes run beyond 300 feet in depth,
the Keystone No. 5 is specified.

FUELS

The standard fire-box of the Keystone Drill will take wood
of about 18 inches in length by 6 to 8 inches in thickness.
Seasoned wood is the best, of course, but a clever fireman can
keep up steam with damp and green fuel that would appear
almost useless. It is often possible, and always desirable,
that supplies of wood fuel be prepared in advance. Coal
may be used interchangeably with wood, the Keystone grate
being suited to either, but a supply of extra grates is advisa-
ble if coal is to be burned. The machine can easily be
equipped with an oil-burner where proper fuel is secur-
able and when so fitted the costs of operation are mate-
rially lowered. In many parts of Alaska, Keystone Drills
fitted with gasoline engines serve best. The drill will use a
little less than half a cord of wood to a ten-hour shift if
the wood be of average worth, and the operations require
four to six barrels of water.



24 DRILLING FOR PLACER GOLD

EXTRA EQUIPMENT

There are listed hereafter not only the standard equip-
ment for placer testing, but also a selected list of extras and
spares, with the accessories, that intimate acquaintance with
field conditions prescibe as proper and necessary adjuncts to
speedy and efficient work. Let it be borne in mind that the
search for gold is carried on in the far places of the world,
and that, except in those few instances where operations are
amid the conveniences of civilization, placer prospecting
parties must rely largely on their own resources. Indeed, it
is the ruggedness of the Keystone Drill and the simplicity
of its upkeep that have raised it so high in favor! Again,
speed in carrying out the work is invariably to be desired;
there is always an overhead expense in maintaining the crew
that counts heavily in the event of lost time. The simple
precaution of carrying a complete outfit and ample replace-
ment parts will insure against excessive expense and irksome
delay. The drill-bits must be sharpened in the field that
must be provided for. Sand pump valve packings wear out
even an extra valve assembly should be carried as precau-
tion against embarrassment due to breakage. Continued
use eventually * 'fatigues" the bolts for the driving clamps.
Connecting-rod brasses require replacement there are
many possible mischances of minor nature incidental to the
strenuous work of drilling into impacted gravels. It will be
found that the Keystone list of extras as appended cannot be
safely curtailed if there is to be provision against ordinary
hazards; and, indeed, it may well be increased if the expe-
dition is likely to work for a long time far from the beaten
track. A complete set of carpenter and blacksmith tools
will then be found a worthy addition.



DRILLING FOR PLACER GOLD 25

PACKING AND SHIPPING

For domestic use the Keystone Drill will generally be
shipped completely assembled. For use abroad or in dis-
tant fields it may be partially dis-assembled and crated.
The new machine, ordered from the branch of the Keystone
Driller Company, will be carefully inspected to insure imme-
diate readiness for operation. A machine once used, that is to
be transported to a new field of work, should be carefully and
thoroughly looked over by the Engineer so that possible delay
or confusion at time of delivery may be obviated. The
machinery and tools should be checked as complete and in
perfect working order. Packages and crates should be num-
bered and listed to permit of ready identification. All
should be plentifully greased to prevent oxidation in transit.
The rope should be protected from moisture. Steam en-
gine oil and greases should be included in the shipment if
there is any uncertainty as to the availability of these in the
field. Four 3" by 12" planks are often shipped with the
drill, and prove useful in unloading, moving and blocking.
The sluice-box can be made in the field if a piece of 30" by
60" Galvanized Iron, 20 Gauge, be rolled up and included.
The rocker had best be fabricated on the ground from the
best available soft pine for it is almost sure to be dried out
or broken in transportation. Wise forethought will yield
large dividends in saved time and lowered cost of work !

DRIVE PIPE CARE AND KIND

The pipe recommended for placer testing is the Extra
Heavy Drive Pipe (28 pounds to the foot), for the lengths
are driven and pulled and used over again many times. A
generous supply is most desirable on far expeditions three



26 DRILL ING FOR PLACER GOLD




DRILLING FOR PLACER GOLD 27

times as much as would be required for one average hole may
well be purchased and transported. Short lengths are ad-
vised for greater ease in handling an accepted length is
about six feet for each piece, though the first joint may well
be seven or eight feet. The threading must be accurate and
true ; that there be no waste of time in screwing and un-
screwing ; that the joints will butt in the middle of the coup-
ling, thus avoiding danger of thread -stripping, and so that
all pieces will be interchangeable. Threaded ends should at
all times be protected by couplings or short sleeves. Pipe
ordered from the Keystone Driller Company is threaded to
the "Keystone Standard Cut."

DRIVE PIPE LONGER LENGTHS

However, if the holes are to be more than 60 feet in depth,
longer lengths are advisable. To permit their use, provided
that the ground is dry, the hole is started in a pit about 6 feet
in depth and 5 feet by 7 feet in width and length. This pit
is cribbed lightly at the top to prevent the jar of the opera-
tion of the machine from breaking it down; it is covered
with substantial planks and the weight of the drill is sup-
ported on wide and heavy boards. With such a pit 10-foot
lengths may be comfortably used. In wet ground where
timber is plentiful the drill is often cribbed up so as to be
4 to 6 feet above the surface and the same lengths may be
employed. There are then fewer joints to provide the pos-
sible cause of a "crooked hole" when the gravel is compact,
and less time is taken up in making pipe connections.

DRIVE PIPE INSPECTION

In the field it is customary to use certain pieces of pipe in
a regular sequence, numbering them for identification. It



30 DRILLING FOR PLACER GOLD

be taken to examine the material removed for possible val-
ues, although the hole will usually be started in barren silt or
loam. The stem is then lowered into the pipe and the driv-
ing-blocks bolted on. The attendant, mounted on one of
the cross-pieces of the derrick, will steady and balance the
otherwise unsupported stem, while the panner will hold the
pipe until driven to a depth where it can support itself. Or-
dinarily, in surface soil the first drive may be for two feet,
when the depth and core should be read off and recorded.
A little water may then be added (not too much, on account
of the possibility of its washing down through the loose soil)
and a pumping made without drilling. In hard compact
gravel it is sometimes necessary to drill first but this is a
procedure to be avoided if it is at all possible.

USE OF WATER

The contents of the pipe should be kept thoroughly mixed
with water as the work progresses. In dry ground no more
should be added than is necessary perhaps three or four
feet of it in the pipe. But in wet ground the water-
level should be kept above the water-level outside the
casing. This higher head has been found to be efficacious
in largely preventing the inrush of too great a core and the
intrusion of extraneous values. The Engineer will some-
times find this to be a troublesome point, but one that must
be insisted upon. The operator should continually have be-
fore him the fact that he is not there to make progress, but to
gain a correct sample! Care must also be taken to flood the
drill-stem with a bucket of clean water as it comes up after
the drilling and before the pumping, and to give the sand-
pump a final flush on the conclusion of each pumping. The



DRILLING FOR PLACER GOLD 31

boiler water should be kept in a separate barrel where no
dirty buckets are plunged into it. The water used in the
drill hole should be absolutely free from oil or grease of any

kind.

DRILLING TIGHT GROUND

The pipe will have been carefully measured and marked at
intervals of 6 inches with a water-proof crayon. The
assembled drilling tools will also have been measured and
marked so that at any instant the operator will know the
exact relation of the edge of the bit, at the limit of its down-
ward stroke, to the bottom of the cutting-shoe. Drilling
will proceed until the bit is from 1 to 4 inches above the
lower end of the cutting-shoe; this thickness of impacted
gravel prevents the intrusion of too much material from
without the path of the pipe. This thickness of gravel is
alluded to as the "core". The drill-stem should be turned
slightly by the hand of the operator to keep the blade from
striking in exactly the same place and packing the contents
of the pipe or becoming stuck. If a boulder is encountered
it may be broken up by drilling ahead of the pipe proper
notation being made in the log. Drilling below the pipe is
always a bad and a dangerous practice in placer testing, ex-
cept that in heavy ground or coarse gravel it may be neces-
sary to drill a few inches ahead after pumping to clear the
pipe of a plugged core. Before resorting to this expedient,
it should be ascertained that the water-level in the pipe is
above the water-plane in the ground. Fortunately, in such
heavy, tight gravel there is ordinarily found a stiff clay
which serves to protect the walls of the hole below the drive-
shoe.



30 DRILLING FOR PLACER GOLD

be taken to examine the material removed for possible val-
ues, although the hole will usually be started in barren silt or
loam. The stem is then lowered into the pipe and the driv-
ing-blocks bolted on. The attendant, mounted on one of
the cross-pieces of the derrick, will steady and balance the
otherwise unsupported stem, while the panner will hold the
pipe until driven to a depth where it can support itself. Or-
dinarily, in surface soil the first drive may be for two feet,
when the depth and core should be read off and recorded.
A little water may then be added (not too much, on account
of the possibility of its washing down through the loose soil)
and a pumping made without drilling. In hard compact
gravel it is sometimes necessary to drill first but this is a
procedure to be avoided if it is at all possible.

USE OF WATER

The contents of the pipe should be kept thoroughly mixed
with water as the work progresses. In dry ground no more
should be added than is necessary perhaps three or four
feet of it in the pipe. But in wet ground the water-
level should be kept above the water-level outside the
casing. This higher head has been found to be efficacious
in largely preventing the inrush of too great a core and the
intrusion of extraneous values. The Engineer will some-
times find this to be a troublesome point, but one that must
be insisted upon. The operator should continually have be-
fore him the fact that he is not there to make progress, but to
gain a correc t sample! Care must also be taken to flood the
drill -stem with a bucket of clean water as it comes up after
the drilling and before the pumping, and to give the sand-
pump a final flush on the conclusion of each pumping. The



DRILLING FOR PLACER GOLD 31

boiler water should be kept in a separate barrel where no
dirty buckets are plunged into it. The water used in the
drill hole should be absolutely free from oil or grease of any

kind.

DRILLING TIGHT GROUND

The pipe will have been carefully measured and marked at
intervals of 6 inches with a water-proof crayon. The
assembled drilling tools will also have been measured and
marked so that at any instant the operator will know the
exact relation of the edge of the bit, at the limit of its down-
ward stroke, to the bottom of the cutting-shoe. Drilling
will proceed until the bit is from 1 to 4 inches above the
lower end of the cutting-shoe; this thickness of impacted
gravel prevents the intrusion of too much material from
without the path of the pipe. This thickness of gravel is
alluded to as the "core". The drill-stem should be turned
slightly by the hand of the operator to keep the blade from
striking in exactly the same place and packing the contents
of the pipe or becoming stuck. If a boulder is encountered
it may be broken up by drilling ahead of the pipe proper
notation being made in the log. Drilling below the pipe is
always a bad and a dangerous practice in placer testing, ex-
cept that in heavy ground or coarse gravel it may be neces-
sary to drill a few inches ahead after pumping to clear the
pipe of a plugged core. Before resorting to this expedient,
it should be ascertained that the water-level in the pipe is
above the water-plane in the ground. Fortunately, in such
heavy, tight gravel there is ordinarily found a stiff clay
which serves to protect the walls of the hole below the drive-
shoe.



DRILLING FOR P LACER GOLD




Drilling in China behind the protection of a fence and barricade



DRILLING FOR PLACER GOLD 33

DRILLING LOOSE GROUND

If there is loose and running ground there may be but
little drilling necessary, and the utmost skill and experience
of the operator will be called into play to prevent the pump-
ing of too much material. In fact, there will frequently
occur a stratum where the amount of silt and sand pumped
out of the hole will be greater than the theoretical displace-
ment of the drive-shoe a careful recording of volumes will
then give the Engineer data for the approximations and
allowances that must be made. Fortunately, such loose
material seldom contains heavy enrichment. If too thick
a core is maintained, there is a possibility of its becoming a
plug in the pipe and crowding other material aside as it is
driven. The whole science of accurate drilling consists in
pumping as nearly as possible the entire material in the path
of the pipe and no more! No two pieces of ground will
react to drill operations in just the same way; indeed, data
have been collected which show that no two skilled operators
will secure exactly parallel results in the same hole! Here,
as elsewhere, crops up the personal factor which the Engi-
neer will study and reflect in his final calculations. In most
work, however, variations will be so slight as to be ignored,
or will largely compensate.

USE OF JARS

After some depth has been reached, or where boulders
threaten to ' 'stick" the drill bit, there may be occasion to
put on the jars not only to afford the impact necessary to
loosen the bit by the jerk they can exert, but also for their
added weight. Generally, however, they are quite unnec-
essary.



34 DRILLING FOR PLACER GOLD

PUMPING

When the operator has broken up and loosened the mate-
rial nearly to the bottom of the pipe he will throw the crank
wheel out of gear and the cable reel into gear, thereby hoist-
ing the tools clear of the pipe, and will swing the stem out of
the way usually throwing it over and behind the cross-arm.
One pail of water should be dashed over the stem as it rises ;
more water should be added before pumping, as previously
described. The Vacuum Sand Pump is then dropped into
the hole, and rapidly raised and lowered two or three times
to suck in the material. This pump contains a plunger
which travels through its whole length. The rapid dropping
of the pump forces this down and when the sand reel is
thrown into gear, this ' 'sucker" is drawn up so rapidly as to
produce a vacuum in the lower part of the pump, thus
opening the valve and drawing in the loosened contents of
the pipe. The secret of successful pumping lies in impart-
ing a properly rapid motion to this plunger and the power
and control of the Keystone Drill enable the operator to re-
cover the gravel, slimes, sand and mineral enrichment with
a remarkable thoroughness. Two pumpings are usual in
ordinary work where progress is made a foot at a time. Of-
ten time can be saved by pumping immediately after driv-
ing, drilling only when there remains more than 2 or 3 inches
of core. The two pumpings, the one before and the one af-
ter drilling, are preferably caught in the same pan and con-
centrated in one operation. When extraordinary care is not
required the material may be poured directly into the pan
which will have been placed across the frame of the sluice -
box, the slimes being allowed to accumulate in the box for
the final * 'clean-up" on completion of the hole the panner



DRILLING FOR PLACER GOLD 35

making proper record of the values therein contained. This
sluice-box, a wooden frame with a half-round trough of gal-
vanized iron, is mounted on wooden supports directly in
front of the drill and extending forward away from the pipe.
The attendant will carry the valve end of the pump out from
the pipe as the operator easily slackens the cable (not enough
but that the line still carries most of the weight of the
pump) until he can lay it over the box; then he will raise
the valve end and dump its contents into the pan. The
pump should then be washed clean, both inside and out,
with clear water and allowed to rest on top of the sluice-box
(so that sand-line and drilling cable do not touch) ready for
the next pumping.

CHECKING VOLUME OF MATERIAL PUMPED

If variable cores and unusual conditions suggest a greater
accuracy in the observation of the relation of the recovered
material to theoretical displacements, the entire pumping
may be at once emptied into the sluice-box. At its lower end
will be placed a large tub of water containing a pail into
which the material falls. The contents of this pail will be
measured before panning the tub will gradually collect the
slimes for the final accounting. The pail had better be cali-
brated and a chart prepared showing the cubic feet of mate-
rial for each inch which the surface lies below the top of the
pail. There is here given (Plate "E") an actual record of
such data as presented in the report of a well-known Engi-
neer.

DRIVING

After the pumping, the drill-stem will be swung back into
the hole and carefully lowered to rest on the surface of the



36 DRILLING FOR PLACER GOLD




DRILLING FOR PLACER GOLD 37

material within the pipe. A measurement should then be
taken to ascertain the amount of material above the drive-
shoe and record made thereof as "core after pumping."
The drive-blocks are then bolted on and the pipe driven the
proper distance, usually a foot, more in loose and easy
ground where no values are anticipated; less in very hard
and refractory gravel or resistant sand. It has already been
noted that there are occasions when lack of progress indi-
cates that one may reluctantly drill ahead to facilitate driv-
ing, but the Keystone Drill has ample power to cope with
exceptionally hard formations and the logs of Keystone
drill-holes are singularly free from record of this expedient.

FINISHING HOLE

Most holes are continued to the hard rock, shale, de-
composed granite, tufaceous lava, or barren stratum that
marks the limit of recoverable values. The Engineer will
usually prefer to be present at the conclusion of a hole, not
only on account of the greater concentration of material
usually encountered on bedrock, but to observe what he may
of the character of this formation. The pipe should be driv-
en to a depth that makes certain of bedrock and of the total
absence of values but not to a depth into the bedrock that
will make pulling a slow and tedious process. The full pur-
pose of the test hole having been supposedly now accom-
plished, the operator may, at will, drill a few feet into the
bedrock. This will prove whether his supposed bedrock is
or is not a large boulder.

PULLING PIPE

The long stroke of the Keystone Drill, together with its
responsive control, facilitates the withdrawal of the heavy



38 DRILLING FOR PLACER GOLD

drive pipe for use over and over again. The stem is de-
tached from the rope-socket and the "puller" screwed on
tightly. The puller knocking-head is then attached to the
top length of pipe and the machine started with the slack
so controlled as to strike a forceful upward blow. If the
pipe yields but slowly, the pulling ring and lifting jacks may
be employed. The water-level in the hole is usually meas-
ured during this operation, although, if the hole "stands up",
more nearly accurate information may be obtained by delay-
ing this reading for a day or so. When the last joint is
removed, the drill-stem is again fastened to the rope-socket,
loaded into the bed of the machine, the jacks removed,
and the outfit moved to the next hole.

PANNING

Under ordinary conditions the panner will concentrate
the recovery of each pumping in his pan. After removing
all but the minerals and black sand, he will estimate the
weight of gold in milligrams and also count and record the
colors. It is customary to record these as of the "First",
"Second" or "Third" grade. A "Third" grade color is one
that is large enough to be individually counted, yet below
two milligrams in weight. A color between 2 and 7 milli-
grams is of the "Second" grade above 7 of the "First"
grade. This counting of colors and estimate of weight
serves several purposes. It shows the occurrence of values
according to the depths ; it gives data for the Engineer if the
recovery of a pumping is to be later discarded or discounted ;
it gives some idea of the worth of the ground if by accident
the recovered values are lost or contaminated. The gold
from the various pannings as the hole progresses will be ac-



DRILLING FOR PLACER GOLD 39

cumulated in the same globule of mercury. This, preserved
in a glass tube, will be kept on the person of the panner. On
finishing the hole the tailings will all be re-run through the
rocker, together with the slimes from the sluice-box and tub,
and any values added to the mercury. This will then be
handed to the Engineer, together with the log of the hole
which it is also the panner's duty to keep. When the drill-
ing is being prosecuted by a night-shift it has proved unwise
to attempt panning by artificial light. Under such circum-
stances the pans are preserved for concentration on the fol-
lowing day, being marked by a wooden "paddle" on which
the proper identification of the pumping may be pencilled.
The panner is held responsible for the correct recording of
the progress of the work, of the cores and for the recovery of
every particle of metal.

TIN PROSPECTING

The procedure in evaluating tin placers is practically the
same as for gold except that the panner will screen his ma-
terials and grind the larger particles of tin to determine a
sample and gain an assay that will declare as to the propor-
tion of dross in the heavy tin-stones. Placer gold particles
are ordinarily unadulterated with quartz not so with tin

"nuggets".

PLATINUM

Inasmuch as platinum is not picked up by the mercury, it is
necessary to save for assay the heavier concentration of the
pannings. In rare cases, the platinum will represent no small
proportion of the values in all placer fields it is a wise precau-
tion to make a careful test of its presence in commercial quan-
tities. For the ordinary gold-saving, tables of the modern
dredge make a remarkable recovery of these heavy particles.



40 DRILLING FOR PLACER GOLD

FIRE ASSAYS IMPROPER

Every Engineer has heard of instances where through
ignorance the concentrate from auriferous gravels has been
sent to the assay office for a fire test. This grave error is
even today not uncommon. It should be remembered that
the heavy quartz pebbles carry gold that no washing device
can recover and that while field panning and hand concen-
tration methods may be crude, that they are of comparable
efficiency to the gold-saving devices of the dredge and that
more nearly accurate recovery from the sample will be dan-
gerous and misleading. The ' 'black sand" concentrate from
the bottom of the pan, after the mercury has picked up all
visible yellow particles of gold, will often yield a high fire
assay but the recovery of these values by washing or amal-
gamation is even more nearly impossible on a large scale than
it was in the prospector's pan!

PRECAUTIONS TO BE OBSERVED

On leaving the work at the end of a shift, it is an excellent
idea to throw into the hole a few handfuls of tailings that are
known to be barren. This is pumped out and inspected on
beginning the next day's work an effectual safeguard
against tampering. In fact, it is impossible to salt a Key-
stone Drill hole if even moderate watchfulness is employed.
It is rumored that on one occasion particles of virgin gold
were inserted into the fibres of the drill-rope, these gradual-
ly falling into the hole as the work progressed. The sight
of a few flakes of bright gold on the top of the driving-head
revealed the trick. It is also said that once an interested
property owner loaded a cigarette with precious dust and
flicked the ashes into the pan as concentration was being



DRILLING FOR PLACER GOLD 41

carried on. Salting is only possible by some such fantastic
and wholly unlikely ingenuity. However, the careful Engi-
neer will from time to time check the purity of the quick-
silver which he uses.

FROZEN GROUND

A new technic of drilling in the frozen gravels of the Arctic
has been developed. This work requires experience if it be
done with accuracy; we can only touch on the method em-
ployed. When the pipe reaches frozen strata, drilling and
pumping and panning proceed below it a foot at a time.
There will be some caving, and an irregular hole is pretty
sure to result as thawing proceeds. After bedrock is reached,
the tools are withdrawn and a measured quantity of water
kept at a temperature just above freezing is poured into the
hole. A careful record is kept of the volume necessary to
raise a float one foot vertically and thus is secured an equiv-
alent measurement of the cubic feet of gravel actually re-
moved in each foot of progress. With the new science of
"cold-water thawing" and the renewed interest in Arctic
gravels, this ingenious method of insuring reasonable accura-
cy in prospecting becomes particularly noteworthy and
here again is the power of the Keystone Drill of signal value !

UNUSUAL CONDITIONS

The vast differences encountered in probing the placers
of the world cannot all be dwelt upon in this short treatise.
Indeed, there will be unprecedented conditions now and then
arising that will tax the resourcefulness of Engineer and op-
erator alike. But the ruggedness and yet splendid flexi-
bility of the Keystone Drill adapt it to the hardest tasks.
It can be cribbed up high above marshy ground when long



42 DRILLING FO R PLACER GOLD




DRILLING FOR PLACER GOLD 43

pipe lengths are to be handled. It can be operated from a
scow afloat in lake or river. It is a sturdy machine for
hardy men in rough country!

Here might be introduced a paragraph on the Keystone as
a Shaft-Sinker in frozen strata. The advantage and process
are that : A six-inch hole is first drilled through the frozen
strata. Two or three returns of one-inch pipe connected to
the boiler serves overnight to thaw the material out to
shaft size. The drill-stem having been removed, the cable
and cable reel are, without other change, used to elevate the
mining bucket for the thawed material or the accumulated
water. The machine and its accessories in fact make it a
complete shaft-sinking outfit.



HARRON, RICKARO * MeCONE
SOLE AGENTS



CHAPTER III

LAYING OUT THE GROUND AND
ESTIMATING THE VALUES

SURVEY

The careful examination of a placer deposit requires a thor-
ough survey and an adequate map this being made with
sufficient accuracy and to so large a size that distances may
be scaled with precision. It is not always possible to secure
such a survey in advance the Engineer will often prosecute
such work while supervising the beginning of drill work.

WHAT MAP SHOULD SHOW

On the map should appear property lines, roads, bedrock
outcroppings, and physical limitations of dredging areas; and
it should represent a complete picture of the property not only
for purposes of prospecting, but for later use in buying par-
cels of land and for dredge operations: Perhaps such thor-
ough work will not be completed until there is some assur-
ance as to the desirability of actual exploitation, but the
initial survey may quite as well be conducted so as to be
made full use of if the property ''proves up".

PLOTTING DRILL HOLES

Usually the first drillings will render a verdict as to the
ultimate value and dredgability of the property. Accord-
ingly, it is often desirable that they be well scattered so that
they may roughly reveal the worth of the entire acreage.
Yet, if the results are favorable, this first work should have
been so done that it fits into the complete campaign of
prospecting.



DRILLING FOR PLACER GOLD 45

EXPLORATION WITH DRILL

In a channel deposit the Engineer will often stake out
lines at right angles to the stream flow and mark proposed
holes just as if he were assured of favorable results. Then
he will start drilling by driving alternate holes on alternate
lines with the purpose of later completing the work when
the value of the area has been reasonably established. In a
"blanket" deposit he may chart his entire scheme of drilling
then actually drill here and there over the entire acreage
until a complete exploration has been justified.

LAYING OUT HOLES IN STREAM DEPOSIT

In all ordinary deposits a Keystone Drill hole to every two
to four acres will be adequate to yield complete data as to
values. The plotting of proposed drill-holes will be made
with this in mind. Several "channel" or stream deposits
have been appraised by drilling holes at a distance of 150 feet
on lines that are 1000 to 1500 feet apart. The location of
holes on Plate "A" is typical.

"BLANKET" DEPOSITS

As is hereafter described, the marking of a wide acreage
of auriferous gravels into equilateral triangles, placing drill-
holes at their apices, is an excellent method of conducting an
exploration. The final calculations are then quite simple
and the chance of confusion and error is eliminated. Some
Engineers prefer to plot the field in rectangles, drilling at the
corners of each parcel. Still others divide the field into
squares and drill at the center of each square. This brief
treatise does not attempt to argue the merits of various
methods but to fully present one method for the uniniti-



46



DRILLING FOR PLACER GOLD




DRILLING FOR PLACER GOLD 47

ate and record the several angles of consideration as memo-
randa for the more experienced.

TREATMENT OF AMALGAM

The Engineer will receive from the panner a small phial
in which he has preserved the mercury containing the gold
from the sample. This he will treat with dilute nitric acid
(Sp. Gr. 1.42 plus an equal volume of distilled water) in a
test tube over the flame of an alcohol lamp wash well with
boiling water to which a few drops of alcohol have been
added dry and anneal in a small annealing cup or porcelain
crucible and weigh the clean dust on scales that are accu-
rately sensitive to a milligram. Pocket scales are made that
are sufficiently precise for this work. These operations should
be carried out in a room free from dust or air currents and
with clean reagents and containers. Then the Engineer,
with the weight of the gold and the log of the hole before
him, proceeds to the calculation of values in "cents per cubic
yard" the accepted basis for the evaluation of placer prop-
erties.

DETERMINING FINENESS OF GOLD

To properly translate his gold values he must appraise the
fineness of the metal peculiar to the property in question.
Many Engineers insist on sending a sample of the gold col-
lected to the nearest available authority on quantitative
analysis to determine with accuracy the proportion of gold
and silver. Sometimes, if platinum be expected as occur-
ring in the sands, as large as possible a sample of the panner's
concentrate is also sent and a determination of that metal
likewise requested.



48 DRILLING FOR PLACER GOLD



VALUE OF MILLIGRAM OF GOLD

A customary approximation, when accurate data are lack-
ing, is to call a milligram of gold worth .06 cents. This is
based on gold that assays $18 . 66 worth of pure metal to the
troy ounce of 480 grains one grain being equal to 64 . 8 mil-
ligrams.

CALCULATION OF CUBIC CONTENTS
OF DRILL-HOLE

A 1 foot hole yields .3068 cubic feet of material. If that
material produces 1 milligram of gold then a cubic yard will
produce 2 7 /. 3068 times as much or 8.8 milligrams.
But, on a basis of gold that is worth $18 . 66 per ounce; one
milligram is worth . 06 cents. Therefore a hole one foot in
depth that yields one milligram of gold proves a value of 8 . 8
times . 06 or 5 . 280 cents. Then, since this figure repre-
sents the yield of a hole of the unit depth of one foot and the
unit recovery of one milligram we have only to divide it by
the depth in feet and then multiply it by the number of mil-
ligrams recovered to learn the indicated values in cents per
cubic yard for any hole ! A table is included in this booklet
which reduces this arithmetical calculation to one operation.
(Plate "G"). It is based on the working out of the following
formula :

3068 X x P t p,, x Mgms. = Value in Cents per Cubic Yard.

. 3068 Equals area of drive shoe in square feet.

27 Equals conversion factor to cubic yards.

. 06 Equals value of gold in cents per milligram.

"D" Equals recorded total depth of hole in feet.

Mgms. Equals number of recovered milligrams.

In this appended table there have been substituted vari-
ous depths for the factor "D" there remains only to multi-



DRILLING FOR PLACER GOLD 49

ply the partial result opposite to the actual depth to bedrock
by the number of milligrams to find the indicated value in
cents per cubic yard.

COMPENSATION FOR EXCESSIVE CORES

Occasionally a hole will be reported that varies in a
marked manner from normal. For instance, suppose that
between the 20 and 25 foot marks there was trouble with a
defective pipe joint or a plugged core that kept out the proper
amount of material or an inrush of far too much sand
and gravel. The panner's log would show an estimate of 18
milligrams of gold in this five feet of progress and extracted
from either too little material or too much. Suppose that
the amount of material actually recovered and the theoreti-
cal recovery do so fail to coincide, what then? Some Engi-
neers prefer to throw out this portion of the hole ; it is surely
not necessary to discard the whole drilling by reason of this
mishap, nor yet should such unreliable data be incorporated
as part of the whole. In this hypothetical case the Engineer
would subtract five feet from the recorded depth and 18 mil-
ligrams from the weight of the gold as finally wieghed ; then
calculate his values. Other Engineers will credit values to
this five feet of hole according to the average of a like dis-
tance above and a like distance below the error. This seems
a likely way to approximate the truth.

OTHER CONSTANTS IN COMMON USE

But the constant of . 3068 (based on the calculated volume
of a cylinder 1 foot high with a base l l /2 inches in diameter)
is only one of several that have been widely used in the past
and are more or less favored today.



50 DRILLING FOR PLACER GOLD

CONSTANT OF .3333

It was once a favorite practice to estimate values on the
above basis and then to discount the completed returns on
the appraisal of the property by 10 or 15 per cent as a meas-
ure of safety and conservatism. However praiseworthy
this desire to err only on the side of safety, this procedure is
hardly professional or sensible. At least one serious error
has occurred where the values were so discounted twice
through a misunderstanding. But this desire to lean to the
safe side led to the adoption of an arbitrarily fixed constant
of .3333. This was widely used by those who insisted on
ultra-conservatism in the estimating of dredging values and
also by those who maintained that the beveled edge of the
Keystone drive -shoe as well as the entire method of opera-
tion allowed more material to enter the drill-pipe than
strict theory would indicate. The use of the constant . 3333
gave final values that were 8.7% less than when the .3068
factor was employed.

KEYSTONE CONSTANT OF .27

But from the very earliest day of the development of the
technic of prospecting, there have been many Engineers who
have favored the constant of . 2 7 (one cubic yard of material
to each 100 feet of pipe). This has been widely called the
"Radford Factor" or the "Keystone Constant." Its use
was first scouted as too likely to exaggerate values, but in
the light of recent comparisons of estimated prospecting to-
tals and the actual recovery of subsequent dredge returns,
this "Keystone Constant" climbs back into secure favor.
One large Company that has successfully operated many
dredging properties in different parts of the world for a long



DRILLING FOR PLACER GOLD 51

time preferred the conservative constant of . 3333 but it is
noteworthy that their estimates today are usually worked up
on the basis of the " Keystone Constant."

REASONS FOR THE KEYSTONE CONSTANT

The churn drill, functioning by impact", continually acts
to drive the gravel downward before the pipe and to settle
the heavier particles of gold and precious metal. If any
metal ever does escape the action of the pump, it is more
likely to be these same heavier particles. At the conclusion
of the hole the last drilling may have driven a few particles of
the metal down out of reach into the bedrock. The panner
may always, despite the most scrupulous care, lose a tiny
proportion of the values from the splash of the pumping or
in the rocker. There is more likelihood of missing some of
the values than of getting more than the due amount.
There are many sound reasons to justify the practice of
crediting the recovered gold to a volume of material some-
what less than the theoretical amount and the "Keystone
Constant" does just that.

NO ONE CONSTANT INVARIABLY PROPER

Few Engineers will use the same constant under all con-
ditions. For there are many variables to consider in trans-
lating the work of a drill to a well considered prophecy of the
values that the dredge will recover. The Engineer, in
choosing his constant will weigh many things. The per-
sonality of his crew cannot be ignored. The time of the year
in which the work is done will have an effect a panner can-
not work in freezing weather with the same accuracy as in
the pleasant days of summer. Rich and streaky channels of



52



DR I LLING FOR PLACER GOLD




DRILLING FOR PLACER GOLD 53

heavy gold concentration will usually drill higher than the
expected recovery a small gold content evenly distributed
in loose ground will often show to the drill as less than what
the dredge will later actually save. These matters will be
discussed more at length in the final chapter of this article
"Chapter IV Reliability of Keystone Samplings".
Most Engineers today will use the "Keystone Constant" as
the proper basis for their estimates.

COMBINING VALUE OF VARIOUS HOLES

When the Engineer has correctly evaluated the various
holes he faces the problem of combining them to gain his
tract values. It is customary to plot the holes on a large
map, noting dredging limits as determined by surface con-
tour, by exposed rimrock or reefs and also marking proper-
ty lines. If the values fade off into barren areas there should
be marked the probable boundaries of dredging values
roughly estimated at the probable cost of the dredging
operations. This may vary from 5 cents where a large
dredge is to work under the most favorable conditions to
1 5 cents or even more where inaccessibility, expensive power
or frozen ground offers difficulties. If the ground shelves to
shallower depths the limiting depths should also be plotted.
These vary for different dredges, but the average dredge can
hardly dig its flotation in ground that is not at least 12 feet
in depth. The yardage should be estimated from this com-
pleted plat with all possible accuracy. It is perhaps true
that a little carelessness or a wrong conclusion at this point
will affect the figure of total recoverable gold more than any
other error that is likely to be made. It may be noted in
passing that most Engineers add to their yardage calcula-



54 DRILLING FOR PLACER GOLD

tions the amount of ground that the dredge buckets will
handle in digging bedrock to the depth of one foot. This is
a necessary procedure in actual dredging and one that dilutes
the auriferous gravels with barren material.

PRINCIPLE OF EVALUATION

The only principle involved in calculating the value of a
tract of ground lies in the necessity of giving proper "weight"
to each drill-hole in that area that is, in letting a drill-hole
affect the final result in proportion to the area which it rep-
resents, or "governs." Merely to add the values of the
holes and divide by the number of them is an elementary
error.

CALCULATION WHEN HOLES ARE SPACED
EQUIDISTANTLY

If the area of auriferous gravels is a "blanket" deposit and
it has proved feasible to lay out the holes so that they are
equi -distant, this calculation is a simple one indeed. The
ground is then divided into equilateral triangles, and the
depth of each area, and its values in cents per cubic yard is
the average of the product of the depths and values of each
hole. Thus, the deeper the hole, the greater its effect on the
values of the area. The value of the tract is the average of
the products of the volume of the triangles and their values.
If the holes are not evenly spaced, to connect them by lines,
to figure the area of the enclosed triangle and to allot to it
the average of the products of the depths and values of the
three holes at its apices is not far wrong. . To be sure, there
is a slender factor of error that increases as the "triangle"
departs from the equilateral, but this is a compensating
variation that may often be ignored.



DRILLING FOR PLACER GOLI> 55

OTHER METHODS

There are Engineers who favor other and more compli-
cated calculations but the principle to be followed is a sim-
ple matter of common sense that lends itself to translation
in ordinary arithmetical terms. Discussion of the infinite
number of special problems that the prospecting Engineer
will meet can only bring one back to the starting point. It
has been shown by actual test that rarely will two Engineers
go about combining the results of two or more drill-holes in
exactly the same way. But there is little chance to go far
wrong. If there be a large area and many holes, the result
will surely be within the limits of error of the entire technic
of field work ! Set several men to counting a pile of nails
some will count one at a time ; some two at a time and some
five at a time but the complete tally will be the same no
matter what system best fitted the idiosyncrasy of the coun-
ter! The best argument against meticulous precision or
vast elaboration in the calculation is the admitted fact that
the same Engineer cannot get the same results from the
evaluation of the same scattered holes at two different
times. But the percentage of disagreement will be well
within safe limits. To be sure, there are occasional per-
plexing problems where the odd areas at the side are of un-
usual shape, or where it becomes necessary to separate the
value of some particular tract or acreage from the calcula-
tion of the whole area. But these, too, yield to arithmetic
and to the elementary principle of allowing each .drill-hole
to influence only that territory to which it is the nearest.
"HIGH HOLES"

Two or three of the holes are most likely to be very much
higher than the others. Sometimes, they are so large in com-



56 DRILLING FOR PLACER GOLD




DRILLING FOR PLACER GOLD 57

parison with surrounding holes that there is a very natural
suspicion of a grave error. There is no standard method of
treating these "high holes" in the final calculation differ-
ent Engineers favor different methods. In fact, nowhere
does the "personal" factor enter more strongly than in mak-
ing the decision as to how such high holes shall be counted.
Some hold it advisable to put down a check hole about six
feet from the high hole. The check hole rarely shows values
as great sometimes it is surprisingly low. Usually, the
average of the high hole and check hole is taken and figured
into the final result as though there were but one hole at
that point. It may be here noted that the gold content of
more than one property has been padded by figuring in the
check holes on an equal basis with the other drillings, the
fact being forgotten or ignored that these holes were put
down at favored locations and were not equally representa-
tive samplings. Usually, the Engineer is content to check
one or two of the high holes and to regard the others in the
light of what the first check holes reveal. If the property
as a whole is of even enrichment, there is little likelihood
that a second hole will confirm exceptionally high results of
a first. On the other hand, if it is known to be "spotted",
an occasional high hole can be accepted at full value without
question. Indeed, the plotting of the several high holes
will sometimes indicate a rich streak or channel. Extra
holes are often put down to determine the course and extent
of such an area of attractive concentration not as check
holes, but as supplementary drillings. Once that such an
enrichment is established, there is of course no argument
against accepting the higher values of the holes within such
territory. If the high yield of a hole can be traced to a



58 DRILLING FOR PLACER GOLD

single large piece of gold, or a nugget, it is customary to leave
out the weight of this persumably accidental bit in calcu-
lating the value. Some Engineers, in what is perhaps an
over-anxiety for conservatism, do not include the high holes
in their final calculations. Still others cancel them against
the low holes in the apparent conviction that the very
high and the very low are due to errors which may be bal-
anced. Another method is to take half the result of a high
hole which is more a concession to timidity than to com-
mon sense. Most dredge operators will report that a high
hole is never proved up by the work of the dredge. Yet
from actual results it seems to be an established and a safe
and proper practice that the occasional high hole may be
included in the calculations if it was correctly drilled and
if there is no mechanical error to be detected. For if the
drill caught a stray bit of concentration behind a boulder or
tapped a random streak of enrichment, there are quite cer-
tain to be many scattered areas of similar values that the
dredge will recover. It seems fallacious and hypercautious
to count out the one or two holes of most attractive result.
But it must be remembered that only very rarely does such
a high hole actually reveal a definite area of surrounding
yardage of a corresponding richness only adequate check-
ing could prove that! But it does have a proper part in
the summation of the whole!

CALCULATION OF STREAM CHANNEL VALUES

If the auriferous gravels follow a comparatively narrow
and well-defined channel, it will have been prospected by
lines of holes that cross it at intervals of a thousand feet,
more or less, the holes spaced rather close together, depend-



DRILLING FOR PLACER GOLD 59

ing on the width of the channel. The calculation of the
values of the line may be made as is outlined and exemplified
on Plates "A", "B," and "C." The principle is exactly the
same as has been above outlined. Each drill-hole governs
the length of "line" that is nearer to it than to any other
drill hole. The figuring is facilitated by making a diagram
of this channel cross-cut being careful to lay out the dredg-
able limits at the side with due regard to the surface contour,
bedrock elevation, barren gravels and practical digging
depths. Ordinarily, the line will end at an actual drill-hole,
but sometimes it will seem reasonable to extend it somewhat
beyond a hole with acceptable values and depth part way to
another hole that is either shallow or barren, or toward a
further and approximated dredging limit. It is then nec-
essary to credit to this "proportionate point" or "fictitious
hole" a calculated value and depth these assumptions to
be made with due regard to the comparative distance of the
two drill-holes that govern the estimate. This is shown on
Plate "A" there are such "proportionate points" at the
right limit of Line 9 and at the left limit of Line 10. No
matter if the holes be spaced irregularly, the area which
each governs may be visualized and correctly calculated.
To simplify calculations, the method exemplified in Plates
"A" and "B" is often resorted to the value of the area be-
tween two holes is estimated by multiplying the distance by
the average depth and the value. A study of the Plates
will reveal the whole process as reproduced from an actual
report. To obtain the value of the "block", or the dredga-
ble area between the two lines, the procedure as illustrated
on Plate "D" may be followed. The calculation is some-
times called the determination of block values by the "Cen-



60 DRILLING FOR PLACER GOLD

ter of mass" formula. The lines are projected (by using the
cosine of the angle which they make with an ' 'altitude" line
connecting their centers) and the average area of the pro-
jected bases, multiplied by this altitude, gives the volume of
the "block." It should be noted that the lines affect the
total value of the enclosed block not by their comparative
lengths but by the area of the channel that they cut.
In the same way, the blocks may be added to find the total
yardage and total gold content in a property but the
average value per cubic yard must be figured by allowing
each block to affect the result in proportion to its yardage.
Thus, the block yardages times the block value, added, di-
vided by the sum of the yardages will give the value of the
tract. It is often desirable to estimate as nearly as may be
the value of a piece of land within certain property lines
often so bounded as to have only one or two holes actually
within its confines. The calculation may be made by the
use of "proportionate points" or fictitious holes which are
credited with a depth and a value that are derived from com-
bining the value and depth of the two nearest holes in a pro-
portion that is in inverse value to their distance away.
Such estimates can be called little more than "intelligent

guesses."

SUMMARY OF CALCULATION METHODS

In the discussion above, the plotting of the cross-cut of a
channel has been pre-supposed. Referring to this drawing,
the Area between two holes, which is ordinarily a trape-
zoid, is the average of their depth multiplied by the distance
between them ; the Value of this Area is the average value
of the two holes multiplied by the Area ; the Value of the
Line is the sum of all these products divided by the Area ;



DRILLING FOR PLACER GOLD 61

the value of the Block is the sum of all these products in
one Line, plus the sum of all these products in the second
Line, divided by the added Areas of the two cross-sections,
and multiplied by distance between the lines.

WHAT REPORT SHOULD COVER

The experienced Engineer will include in his final report
of the property much beyond the mere calculation of yardage
and values. For it is quite possible that that very report
will be the dredge designer's sole source of accurate data re-
garding the physical conditions with which the dredge must
cope. Modern firms prefer to design a dredge to fit the
property. Even a used dredge, if torn down and trans-
fered to a new property must be largely altered to meet the
somewhat different conditions of soil and depth. Accord-
ingly, there are here suggested the various bits of infor-
mation upon which a thorough report will touch :

Character of bedrock.

Water-level with reference to surface and to bedrock.

Are boulders present? Their maximum size.

Character of gravel loose, cemented, clay, etc.

Kind of gold large or fine ; flaky or rusty.

Are special gold-saving devices indicated for nuggets or
for flour or oxidized gold?

What are climatic conditions on property? Must dredge
be specially equipped to lengthen its working season?

What are transportation conditions with special refer-
ence to heavy dredge machinery?

What power is available for dredge construction and
operation? Its probable cost?



62 DRILLING FOR PLACER GOLD




DRILLING FOR PLACER GOLD . 63

What is recommended size of dredge for efficient operation
and for proper exploitation of available yardage?

What about water supply?

What is maximum grade of ground in which dredge will
be called upon to work?

Where may dredge be best built with relation to greatest
conveniences for construction and good values as well
as in accord with the best economic plan for future
operations?



64 DRILLING FOR- PLACER GOLD




CHAPTER IV

RELIABILITY OF KEYSTONE
SAMPLINGS

Actual Instances of Comparison Between
Drill Estimates and Dredging Returns

KEYSTONE ESTIMATES NOW CHECKED

If gold particles were uniformly distributed, uniform
samplings would exactly determine the value of the whole.
But the precious flakes are laid down according to no mathe-
matical law; rather by the uncertainties of shifting currents,
of spring freshets, of endless reconcentrations. Even a defi-
nite ' 'pay-streak" begins unexpectedly and ends abruptly.
Seldom will a dredge recover a comparative amount of gold
in two successive days of operation. Yet the records of a
generation of placer gravel exploration have proved that a
reliable appraisal is quite possible with the Keystone Drill.
Yet Engineers rarely expect a second drill-hole, sunk a few
eet from a first, to yield values that are in close accord;
nor are they surprised when a shaft, put down around a
drill-hole, presents a considerable discrepancy in values.
No one expects a flake of ore, chipped from one part of a
vein, to assay the same as another flake from near-by.
Yet the average of several such flakes will approximately
reveal the proportion of mineral in the ore-body. The the-
ory of Keystoning is the theory of averages let the sam-
ples be fairly collected, correctly measured and properly
assayed and they will collectively indicate the values of the
whole. Once this was purely theory today it is fact.

65



66 DRILLING FOR PLACER GOLD

For in the last few years the results of vast dredging
operations have been totaled and analyzed, and it is
now possible to check them with the predictions of
those who drilled the same areas in earlier years.

AGREEMENT ON OREGON PROPERTY

A placer deposit in Oregon which was the result of stream
action was systematically drilled by lines of holes at right
angles to the flow. The work was carefully done by com-
petent Engineers and the calculations carried out by the
methods illustrated in Plates "A" to "D." This property,
consisting of 121 acres, has today been completely mined by
a modern dredge. Its average depth was 18 feet and there
was an overburden of almost barren tailings covering a
"streaky" enrichment. The original estimates gave the
average value per cubic yard as 16.8 cents and the value
recovered by the dredge was 15.63 cents or 93% of the
estimate. The constant used in computing the drill re-
sults was . 3333 ; had a constant of . 3068 been used, the esti-
mated and actual values would have agreed quite closely.
There were here put down one hole to every 2 . 4 acres.

Yet hardly any two of the eight "blocks", into which the
area was divided by the drill lines yielded the identical
values which the drill forecast in one of them the recovered
value per cubic yard exceeded the estimate by 49 . 4% and
in another it was less by 68 . 2%.

CHECK ON A CALIFORNIA PROPERTY

We reprint from the Engineering and Mining Journal an
account of the balancing of prospecting estimates and dredg-
ing results on a California property section of 118.5 acres



DRILLING FOR PLACER GOLD 67

where the results of 38 drill-holes were used in making the
forecast 14 of the holes being outside but adjacent to the
area dredged.

"The estimated value per cubic yard in this tract was
29.88 cents and the dredge returns were 31.55 cents, a
gain of 5 . 6%. We believe the constant used in figuring the
drill returns on this property to have been .3068. Some
years ago on another and undredged portion of this property
consisting of 493 acres an estimate was made to determine
the gold content. The results from 53 drill holes, which
were within the limits of the tract, were used by taking 70
per cent of their recorded value. Consideration was then
given and use made of the values obtained from dredging
operations which had been conducted adjacent to and
around about two thirds of the tract. Since then 402 acres
of this tract have been dredged and the returns per cubic
yard averaged 12.73 cents. The data used in making the
original estimate were applied to the portion now dredged
and the proportionate values found to be 12.70 cents per
cubic yard."

ANOTHER CHECK FROM LARGE ACREAGE

From the same article we quote another example that
shows a recovery closely corresponding to the estimate,
giving the results produced by operations on three separate
tracts in a large California property, the third tract having
been mined by three dredges:



Average


No. of


Acreage
to Each


Value per Cubic Yard
Dredge Per-


Tract


Depth


Acres


Holes


Hole


Drill


Recovery centage


A




22


.5'


173.


5


x 57


3.2


6.8


7


.82


115%


B




44


.5'


84.





20


4.2


5.9


6


.7


113%


CDr.


#1


51


.8'


183





120


1.5


11.1


9


.64


87%


CDr.


#2


60


.6'


106





41


2.6


11.2


9


.44


84%


CDr.


#3


56


.4'


135





58


2.3


11.6


11


.30


97%



68 DRILLING FOR PLACER GOLD




DRILLING FOR PLACER GOLD 69

x 37 shafts and 20 Drill-holes

On Tracts A and B Constant Used in Calculating Drill Results . 27

On Tract C Constant Used in Calculating Drill Results . 30

CHECK FROM SMALL DREDGE OPERATIONS

"The average results of all the above, proportioned to the
acreage, is a drill value of 9.48 cents per yard, and the
dredge recovery 9.12 cents, or 96 . 2%".

And we quote yet another instance:

"Dredging operations on one property in California have
produced returns which, taken as a whole, correspond quite
closely with the original estimates, and the following de-
tails have been presented covering the work done in the past
three years:



Year


Average
Depth


Acres


No. of
Holes


Acreage
to Each
Hole


Value per Cubic Yard
Dredge Per-
Drill Recovery centage


1918
1919
1920


32
34
29


I 7
4'
8'


19
20
20


94
90
43


11

10

7


1.8
2.1
2.9


10
9
10


39
69
.69


10.64
9.22
14.34


102.4'
95. 2<
134.0'


3
1



EXAMPLE FROM OPERATIONS OF NATOMAS CONS.
OF CALIFORNIA

"The average results proportioned to the acreage show an
estimated value of 10.25 cents and a dredge recovery of
11 .39 cents, or an increase of 11 . 1%".

Perhaps the dredging problems of the Natomas Company
of California have been the most difficult encountered on
large scale operations. Here, on the American River, are
high benches of gravel that is so compact and cemented as
almost to defy the dredge buckets and, down in the
bottom lands, wide areas of softer and shallower ground.
A check, made five years ago on the operation of three of
their many dredges gives a reasonably close agreement.



70 DRILLING FOR PLACER GOLD

Percentage of

Area in Years of Estimate

Dredge Acres Operation Recovered

No. 5 180 10 86

No. 8 106 4 87

No. 9 135 6 101

These results are based on an original calculation using
the constant .30. During the last five years these dredges,
as a whole, have produced about 101 per cent of the cal-
culated recovery !

MONTANA PROPERTY

A portion of a Montana property consisting of 300 acres
was prospected with 77 drill holes spaced at irregular dis-
tances. The average value per cubic yard indicated by the
drilling was 15.83 cents, and the dredge recovery 13.55
cents or 85 . 6%. The average depth of the ground was 40
feet and the larger portion of the values was contained in
the three feet of gravel next to the bedrock. Such a deposit
offers obvious difficulties to accurate calibration.

TABULATION OF AVAILABLE COMPARISONS

The article from the Engineering and Mining Journal
partly reproduced above, written by Mr. Charles W. Gard-
ner, Manager of the Mines Operating Department of the
Hammon Engineering Company, probably the first Engi-
neer to use a Keystone Drill for placer prospecting, con-
cludes with a summary that is of striking interest :

"From all of the properties above mentioned we are able
to segregate 3,743 acres to which we can apply data given in
fairly accurate reports. This combined area was pros-
pected by means of 1,749 drill-holes, or one to every 2.1
acres. The average value per cubic yard obtained by



DRILLING FOR PLACER GOLD 71

drilling was 15.4 cents and the average dredge recovery
13 . 55 cents, or 88%. A comparison of returns, segregated
as to values, is as follows :

Average Value per Cubic Yard Percen tage

Drill Values per Per Centage Drill Dredge

Cubic Yard Acres of Whole Value Recovery Gain Loss

Underll^ 27.9 0.7% 9.2M 8.60^ 6.6%

Underll^ 1638.1 43.8 7.68 9.34 21.6%

Between 11 and 12 c 424.0 11.3 11.28 10.12 10.3

Between 11 and 12 e 480.0 12.8 11.61 16.44 41.6

Between 12 and 20 c 582.5 15.6 16.92 13.10 22.6

Over 20 c 392.0 10.5 45.86 20.93 54.4

Over20c 198.5 5.3 33.15 35.97 8.5

Totals 3743.0 100.0%

AVERAGES 15.40 13.55 12.0

Here is spread before us the work of different Engineers
at different times in many fields. There has been no at-
tempt to trace out the avoidable error in either prospecting
or mining. Suffice it to say that there is included in this
tabulation the exploration of at least two properties where
the excavated material was a clean washed sand and gravel
with little clay and many boulders ; making the forecasting
of the values exceedingly difficult by any method and the
recovery of certain dredges that fall short of the highest
standard of modern efficiency.

ACCURATE PROSPECTING POSSIBLE

Mr. Gardner closes his article with; "We feel that a safe
conclusion to be drawn from all of the above is that when a
property has been sufficiently prospected by an experienced
Engineer, the results intelligently interpreted and the cal-
culations accurately made, the result obtained will indicate
within reasonable limits the gold content.



72 D R I LLING FOR PLACER GOLD




DRILLING FOR PLACER GOLD 73

"Full consideration should be given all these points and
then if the estimated gross value safely and sufficiently ex-
ceeds the cost of acquisition, equipment and operation,
there should be nothing to deter or discourage the invest-
ment of capital in such an enterprise."

HOW DIFFERENT CONDITIONS AFFECT
ACCURACY

Mr. James W. Neill, in an article in the Mining and Sci-
entific Press, says, "If the driller keeps his bit behind his
shoe, and sees that he gets a correct amount of core, there
should be little question of the correctness of a large gen-
eral average, and the Engineer can use such factors of
safety as his experience and the character of the ground in-
dicate. In very loose ground, I personally look for a recov-
ery of full drill values where the gold is coarse and is entirely
contained in the foot or two above bedrock. I think one
will also usually overrun the drill, provided the bedrock can
be dug. That is about the sum of our experience at Snelling. ' '

We quote an extract from an article by the compiler of
this booklet that recently appeared in the Engineering and
Mining Journal; "It may be observed that the accuracy of
results gained by drilling is surprising, considering the com-
paratively small size of the sample. For example, one hole
to two acres in 50-ft. ground would mean that 1 /328,000
part of the gravel was examined. Of course one hole by it-
self means nothing it is only a carefully charted series that
reliably represents actual conditions.

"All available data seems to point to the following facts
regarding the accuracy of drilling :

1. Drill results give high assays where the gold is fine.



74 DRILLING FOR PLACER GOLD

2. Estimates will tally with returns where gold is reasona-
.bly heavy; ground is compact with a little clay; and

prospecting and dredging are intelligently done.

3. The drill will exaggerate the value of very loose ground
where sand and water pressure crowd material into the
bottom of the pipe.

4. The drill will signally' fail to show recoverable gold in
areas of moderately loose ground where gold is dis-
tributed and in comparatively small amount."

SUMMARY

The whole problem is squarely up to the discretion of the
Engineer. He may compensate for the co-efficient of the
personal accuracy of his crew; he may use the proper con-
stant in his calculations ; he may use his own experience and
the now recorded findings of others and translate the
results of his Keystone Drill work to a forecast that bears
the stamp of conviction and accuracy !



CONCLUSION

The Keystone Driller Company sells more
than a mere machine it sells service! Orders
are carefully filled with selected materials and
shipments forwarded with all possible expedi-
tion for we are keenly alive to the difficulties
and hazards of field work. During the score of
years in which Keystone Drills have been the
reliance of prospectors the world over, we have
collected a considerable knowledge of the technic
of placer testing and of the proper equipment
therefor. That data we shall gladly share ; and we
offer our experience to any Engineer, be he out-
fitting for a proposed campaign of prospecting
or meeting a knotty problem in the field!



75



76



DRILLING FOR PLACER GOLD



PLATE "A"




LINE No. 9
Hole 29 49.5'
Hole 30
Hole 31
Hole 32
HoleX



30'
189'
192'
197'
116'
20'

Width at top 744'
Width at bottom 694'



51.6'
49.5'
45.0'
40.0'



4.56c
11.23c
29.75c
14.19c

S.OOc




LINE No. 10

Hole Y 55.0' 18.89c 27.5'
Hole 33 55.5' 18.89c 100'
Hole 34 49.5' 18.02c 200'
Hole 35 40.0' S.OOc 200'
20'

Width at top 547.5'
Width at bottom 500'

KEYSTONE CREEK PLACERS

(From actual drill records)

Key Chart to Estimate of Line 9 on Plate "B"; of Estimate of Line 10
on Plate "C"; of Block Estimate on Plate "D."

NOTE

Left limit of Line 9 determined by low value actual drill-hole. Right
limit of Line 9 determined by approximation of dredging limit and
marked by "fictitious" drill-hole "X."

Left limit Line 10 determined by some physical factor probably an
irregular rim. "Fictitious" Hole "Y." Right limit Line 10 determined
by too low value of Hole #35. Engineer has approximated limit of values
20 feet inside of this Hole and marks "fictitious" hole #35' giving it a
limiting value of 5^.



DRILLING FOR PLACER GOLD 77



PLATE "B"
KEYSTONE CREEK PLACERS Valuation of Line 9

Area of Square Cubic

Block Feet Yards Cents

A equals 49 5 2 x3 742.5 or 27.5 x 3.04 = 83.6

B equals 49 5&516 x 189 9553.9 or 353.8 x 7.89=2791.4

C equals 51 6 ^ 49 5 x 192 9705.6 or 359.5 x 20 49 = 7366.1

D equals 49 - 5 2 &45 x 197 9308. 2 or 344.8 x 21.97 = 7575.2

E equals 45 & 40 x 116 4930.0 or 182.6 x 9.59=1751.1

F equals 40 * 20 400.0 or 14.8 x 3.33 = 49.3



34640.2 1283.0 15.25 19616.7
One foot into bedrock 694.0

35334.2 1308.7 14.99 19616.7

NOTES

There is given to Areas "A" and "F" a value equal to only two thirds
of their governing drill-hole. These small areas are the approximation
of the departure from the vertical of the dredge bank.

Under the "Cents" column is the average value of the two bounding
drill holes.

To the yardage total has been added the barren material resulting
from dredging one foot into bedrock.

The figure 14.99 represents the value in cents per cu. yd. of the line
and is gained by dividing 19616 . 7 by 1308 . 7.



78 DRILLING FOR PLACER GOLD



PLATE "C 1



KEYSTONE CREEK PLACERS Valuation of Line 10

Area of Square Cubic

Block Feet Yards Cents

A equals 55x 2 27 ' 5 756 or 28.0 x 12.59 = 352.5

B equals 55 & 2 55 5 x 100 5525 or 204.6 x 18.89 =3864.9

C equals 55 5 ^ 49 5 x 200 10500 or 389.0 x 18.46 = 7180.9

40 'i flr 4ft

D equals x 200 8950 or 331.5 x 11.51 =3815.5

E equals 40 * 20 400 or 14.9 x 3.33 = 49.7



26131 968.0 15.72 15263.5
One foot into bedrock 500 18.4

26631 986.4 15.48 15263.5

NOTES

See Notes on Plate "B."

The figure 15 .48 represents the value in cents per cu. yd. of the line
and is gained by dividing 15263 . 5 by 986 . 4.



DRILLING FOR PLACER GOLD



PLATE "D"

KEYSTONE GREEK PLACERS
Estimate Gross Value of Block Between Lines 9 and 10

Area of Projected Gross Cubic

Section Area Value Yards

Line 10 = 26131 x .9925 (Cos. 7)= 25935 15263.5 968
Line 9 = 34640.2 x .9563 (Cos. 17) = 33126 19616.7 1283

2)59061 34880.2 2251

29530.5

29530.5 (Average area projected base) multiplied by 945 (Surveyed or
plotted distance between middle of both lines which is altitude of
"block") gives a total cubic content of 27,906,522 Cubic Feet.
27,906,522 Cu. Ft. equals 1,033,367 Cu. Yds.

The Gross Value Factor, divided by Cu. Yds. Factor equals:
2251 )34880 . 2 ( 1 5 . 49 cents Value of block

Total Value of Block equals 1,033,367 times 15.49 or $160,099.70.

As a check on Calculations we may figure the same Total by using the
products of the Line Calculations after adding "One Foot Into Bedrock."

Area of
Section

Line 10= 986.4 Cu. Yds. x .9925 (Cos. 7)= 979.0
Line 9 = 1308.7 Cu. Yds. x .9563 (Cos. 17) = 1251.5

2)2230.5

1115.25
1115.25 x 945 = 1,053,911 Cu. Yds.

Total Value of Block equals 1,053,911 x 15.19c = $160,089.08.

NOTE

A line is drawn connecting the centre of the Lines 9 and 10. These
lines are then projected so as to form a 90 angle with this "altitude"
line. The projected base areas are added, averaged, and multiplied by
the altitude to find content of block in Cu. Yds. Additions and sub-
tractions might have been made for irregular rim.



DRILLING FOR PLACER GOLD



PLATE "'



CORE MEASUREMENTS KEYSTONE PLACERS

Total

Core Measured on Surface Cubic

Core Measured in Pipe Without Slimes With Slimes Feet

as per



Hole Depth Drive


Total


Per Ft.


Total


Total


Average Total


Average Const.


No.


Ft.


Ft.


Ins.


Ins.


Cu. Ft.


Cu. Ft.


Cu. Ft.


Cu.


Ft.


Cu. Ft.


.27


1


110


110


1446


14.32


21.69


30.27


.2752


(Not


Measured)


29.70


2


105


98.5


1539


15.83


23.08


25.18


.2556


39


.53


.401


26.60


3


105


98.5


1521


15.44


22.82


26.30


.2669


37


.80


.384


26.60


4


105


97.6


1477


15.14


22.16


24.87


.2547


38


.82


.398


26.35


5


105


96.1


1600


16.65


24.00


26.33


.2740


38


.02


.396


25.95


6


105


97.4


1493


15.33


22.40


24.35


.2499


36


.00


.369


26.30



7 107 99.7 1529 15.34 22.94 22.36 .2243 28.75



288 26.91



8 98.5 83.0 1402 16.90 21.03 25.24 .3041 32.30 .389 22.41



840.5



12007 15.34 180.12 204.90 .2621 251.22 .3746 210.81



NOTES

Figures under "Depth" represent total from surface under "Drive" they represent
actual drilling. (Holes were started in a pit.)

This Chart, taken from the Report of an Engineer, was prepared by him that he might
compare the core records of various similar holes. It shows work that is reasonably
uniform, with no outstanding discrepancies, and proves that the material actually re-
covered, if discounted for the "swelling" of the gravels, checks very closely with the
theoretical displacement of the drive-shoe.



DRILLING FOR PLACER GOLD



81



PLATE "F"

KEYSTONE DRILLER COMPANY
TABLE FOR FINDING VALUE PER CUBIC YARD

(When depth of drill-hole and weight of

gold in milligrams are known)

CONSTANT .27



Depth to




Depth to




Depth to




Bedrock in




Bedrock in




Bedrock in




Feet


Factor


Feet


Factor


Feet


Factor


10


.6000


26.5


.2264


43


.1395


10.5


.5714


27


.2222


43.5


.1379


11


.5455


27.5


.2182


44


.1364


11.5


.5217


28


.2143


44.5


.1348


12


.5000


28.5


.2105


45


.1333


12.5


.4800


29


. 2069


45.5


.1319


13


.4616


29.5


.2034


46


.1305


13.5


.4444


30


.2000


46.5


.1290


14


.4286


30.5


.1967


47


.1277


14.5


.4138


31


.1935


47.5


.1263


15


.4000


31.5


.1905


48


.1250


15.5


3871


32


.1875


48.5


.1237


16


.3750


32.5


.1846


49


.1224


16.5


.3636


33


.1818


49.5


.1212


17


.3529


33.5


.1791


50 '


.1200


17.5


.3429


34


.1765


50.5


.1188


18


.3333


34.5


.1739


51


.1177


18.5


.3243


35


.1714


51.5


.1165


19


.3158


35.5


.1690


52


.1154


19 5


.3077


36


.1667


52.5


.1143


20


.3000


36.5


.1644


53


.1132


20.5


.2927


37


.1622


53.5


.1121


21


.2857


37.5


.1600


54


.1111


21.5


.2791


38


.1579


54.5


.1101


22


.2727


38.5


.1559


55


.1091


22.5


.2667


39


.1539


55.5


.1081


23


.2609


39.5


.1519


56


.1071


23.5


.2553


40


.1500


56.5


.1062


24


.2500


40 5


.1481


57


.1053


24.5


.2449


41


.1463


57.5


.1044


25


.2400


41.5


.1446


58


.1035


25.5


.2353


42


.1429


58.5


.1026


26


.2308


42.5


.1412


59


.1017



Diameter of Cutting -Shoe 7>2 inches. Value of gold 0.06 cents per milligram
$18.66 per ounce. To find value in cents per cubic yard, multiply number of milligrams
of gold recovered from drill-hole by the factor in the table opposite the depth to bedrock



82



DRILLING FOR PLACER GOLD



PLATE "G"

KEYSTONE DRILLER COMPANY
TABLE FOR FINDING VALUE PER CUBIC YARD

(When depth of drill-hole and weight of

gold in milligrams are known)

CONSTANT .3068



Depth to




Depth to




Depth to




Bedrock in




Bedrock in




Bedrock in




Feet


Factor


Feet


Factor


Feet


Factor


10


.5280


26.5


.1992


43


.1228


10.5


.5029


27


.1955


43.5


.1214


11


.4800


27.5


.1920


44


.1200


11.5


.4591


28


.1886


44.5


.1187


12


.4400


28.5


.1853


45


.1173


12.5


.4224


29


.1821


45.5


.1160


13


.4061


29.5


.1789


46


.1148


13.5


.3911


30


.1760


46.5


.1136


14


.3771


30.5


.1731


47


.1123


14.5


.3641


31


.1703


47.5


.1112


15


.3520


21.5


.1676


48


.1100


15.5


.3407


32


.1650


48.5


.1089


16


.3300


32.5


.1625


49


.1078


16.5


.3200


33


.1600


49.5


.1067


17


.3106


33.5


.1576


50


.1056


17.5


.3017


34


.1553


50.5


.1046


18


.2933


34.5


.1530


51


.1035


18.5


. 2854


35


.1509


51.5


.1025


19


.2779


35.5


.1487


52


.1015


19.5


.2707


36


.1467


52.5


.1006


20


.2640


36.5


.1447


53


.0996


20.5


.2575


37


.1427


53.5


.0987


21


.2514


37.5


.1408


54


.0978


21.5


.2456


38


.1389


54.5


.0969


22


.2400


38.5


.1371


55


.0960


22.5


.2347


39


.1354


55.5


.0951


23


.2296


39.5


.1337


56


.0943


23.5


.2247


40


.1320


56.5


.0935


24


.2200


40.5


.1304


57


.0926


24.5


.2155


41


.1288


57.5


.0918


25


.2112


41.5


.1272


58


.0910


25.5


.2071


42


.1257


58.5


.0903


26


.2031


42.5


.1242


59


.0895



Diameter of Cutting-Shoe 1Y^ inches. Value of gold 0.06 cents per milligram
$18.66 per ounce. To find value in cents per cubic yard, multiply number of milligrams
of gold recovered from drill-hole by the factor in the table opposite the depth to bedrock.



DRILLING FOR PLACER GOLD



83



PLATE "H"

KEYSTONE DRILLER COMPANY
TABLE FOR FINDING VALUE PER CUBIC YARD

(When depth of drill-hole and weight of
gold in milligrams are known)
CONSTANT



Depth to




Depth to




Depth to




Bedrock in




Bedrock in




Bedrock in




Feet


Factor


Feet


Factor


Feet


Factor


10


.4860


26.5


.1834


43


.1130


10.5


.4629


27


.1800


43.5


.1117


11


.4418


27.5


.1767


44


.1105


11.5


.4226


28


.1736


44.5


.1092


12


.4050


28.5


.1705


45


.1080


12.5


.3888


29


.1676


45.5


.1069


13


.3738


29.5


.1647


46


.1057


13.5


.3600


30


.1620


46.5


.1045


14


.3471


30.5


.1593


47


.1034


14.5


.3351


31


.1568


47.5


.1023


15


.3240


31.5


.1543


48


.1013


15.5


.3135


32


.1518


48.5


.1002


16


.3037


32.5


.1495


49


.0992


16.5


.2945


33


.1472


49.5


.0982


17


.2895


33.5


.1450


50


.0972


17.5


.2777


34


.1429


50.5


.0963


18


.2700


34.5


.1408


51


.0953


18.5


.2627


35


.1388


51.5


.0944


19


.2558


35.5


.1369


52


.0935


19.5


.2492


36


.1350


52.5


.0925


20


.2430


36.5


.1331


53


.0917


20.5


.2371


37


.1313


53.5


.0909


21


.2314


37.5


.1296


54


.0900


21.5


.2260


38


.1279


54.5


.0892


22


.2209


38.5


.1262


55


.0884


22.5


.2160


39


.1246


55.5


.0876


23


.2113


39.5


.1230


56


.0868


23.5


.2068


40


.1215


56.5


.0860


24


.2025


40.5


.1200


57


.0853


24.5


.1984


41


.1185


57.5


.0845


25


.1944


41.5


.1171


58


.0838


25.5


.1906


42


.1157


58.5


.0831


26


.1869


42.5


.1143


59


.0824



Diameter of Cutting-Shoe 7M> inches. Value of gold 0.06 cents per milligram
$18.66 per ounce. To find value in cents per cubic yard, multiply number of milligrams
of gold recovered from drill-hole by the factor in the table opposite the depth to bedrock.



84 DRILLING FOR PLACER GOLD



PLATE "I"
KEYSTONE DRILLER COMPANY

GOLD DREDGE CAPACITY CHART

Cubic Yards Elevated per Month of 30 Days at
Various Efficiencies for Different Sizes
(Bucket Speed at 50 Feet per Minute)

Figures are based on an actual operating time of 20 hours out of
each 24.

Size of Dredge 100% Efficiency 80% Efficiency 60% Efficiency

2^Cu.Ft. 89,000 71,000 53,000

3^ Cu. Ft. 108,000 . 86,000 65,000

5 Cu. Ft. 140,000 112,000 82,000

7^Cu.Ft. 182,000 146,000 110,000

9 Cu. Ft. 213,000 171,000 129,000

15 Cu. Ft. 304,000 244,000 184,000

From this table the Engineer may roughly approximate the yardage
of a proposed dredge once he knows the physical and climatic condi-
tions to be encountered and general working conditions.



DRILLING FOR PLACER GOLD



85




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COVOOCOOOCOIOOPO

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W fx 10 m * PO CN -i

<Ninoo^Ti-_r.o_fO<O

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cot^ocot^oco

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r o" co" vo" oo" .-* <*" vo"
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So vo CN o* in i-H
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86



DRILLING FOR PLACER GOLD



FIELD LOG



No. of Hole

Date Commenced.... Date Finished.



DEPTH
FEET


No. of COLORS


FORMATION


CORE


REMARKS


Size

1


Size
2


Size
3









































































































































































































































Total Depth feet. Bedrock feet. Water level feet.

ABBREVIATIONS

T. Tailings S. Sand St. Sticky

F. Fine G. Gravel Md. Medium

C. Coarse Cl. Clay M. Much

V. Very Sm. Some L. Loose



PART II

AUTHORITATIVE ARTICLES
ON MINERAL PROSPECTING

iKEYSTONE/



Reprinted from the Keystone Driller Com-
pany's Catalog No. 2, Edition 1907, and from
various technical Journals.



THE PROSPECTING AND VALUING OF
DREDGING GROUND

Written for the Mining and Scientific Press
By Norman C. Stines

(Published in the Issues of Feb. 3 and Feb. 10, 1906.]

The prospecting of gravel deposits to test their fitness for
dredging purposes is done by boring holes with a drilling
machine, by sinking shafts, or by making a trial run with
what is known as a prospecting 'dredge. It is such work by
means of the Keystone drill that this article attempts to
describe.

In prospecting a piece of ground, the following data must
be ascertained:

1. The average value of the ground per cubic yard and
the distribution of the gold.

2. The character of the gravel.

3. The character of the bedrock and its approximate
contour.

4. The position of the water level as referred to the sur-
face.

5. The amount of water obtainable for the pond.

6. The nature and cost of the power obtainable.

7. The length of the working season.

8. The cost of the land.

The first four points are determined directly by the use of
the drill, and the last four by a careful study of the prevailing
conditions. As this paper is to describe the method of using



DRILLING FOR PLACER GOLD 89

the drill and the interpretation of the results thus obtained,
it will treat of the first four points only.

The machine used in the greater part of this work in
California is the Keystone Driller No. 3, Traction. It is
made by the Keystone Driller Company, Beaver Falls, Pa.,
and costs (at present, 1923) complete f. o. b. at the factory,
about $2700.00. The driller consists of a walking-beam
arrangement operated by a steam engine of 1 1 h.p. This pro-
duces the required motion for raising and dropping the drill,
and for transporting it from place to place. The engine, with
the drilling cable reel, the sand-reel and the socket, drill-stem
and bit, is suspended by a \%" cable which passes over the
rear sheave and over the front one, continuing over the sheave
at the top of the derrick and then down. As the walking
beams are put in motion, the drill is alternately raised and
dropped. The machine makes about 52 strokes per minute
in drilling and about 54 in driving.

LAYING OFF THE GROUND

For the preliminary work, to determine if the gold is
scattered over a large area or if it is confined to a narrow
winding channel, a few holes are sunk from 500 to 700 ft.
apart. If the gold is found to be pretty evenly distributed
over the whole tract, it is divided into five or ten-acre
squares, according to the amount of drilling to be done.
A flag is placed in the center of each of these squares, and
this marks the site of the hole.

If the gold is found to be confined to a narrow winding
channel, the ground is crossed, at right angles to the channel,
by series of holes. These series are from 400 to 800 ft. apart.
At every 100 ft. in each series a flag is placed and this, as



?0 DRILLING FOR PLACER GOLD




DRILLING FOR PLACER GOLD 91

before, marks the place to be drilled. On drilling, the first
hole in any series is placed as near the center of the channel
as possible, and then drilling to one side or the other is only
carried as far as the results warrant. Every fourth or fifth
series is drilled across the tract to be sure that there are no
splits in the channel. This method insures the least amount
of work spent in valueless ground. The series are desig-
nated by letters and the holes by numbers. In this way
they are recorded in the transit notes. When a hole is
drilled, the number in the log-book is also placed in the
transit book and the number from the transit book is placed
in the log-book.

OPERATION OF DRILLING THE HOLE

The machine is moved to one of the flags and set up there.
A hole is then dug to a couple of feet and the shoe-joint is
dropped, then plumbed, and finally the dirt filled around it.
The next operation varies according to the nature of the
ground. Where the soil is deep, the driving blocks are put
on and the casing is driven as far as possible, or to the gravel.
Where the gravel commences at the surface, the drill is first
lowered and the ground immediately beneath the shoe is
drilled. The casing generally settles as the drilling pro-
ceeds; but if it does not, when a sufficient depth has been
drilled, the blocks are put on and the casing driven to a
point about three inches below the depth drilled. The
lower end of the shoe-joint is protected from injury by a steel
shoe, 7K" in diameter, tempered at the cutting edge and
slightly beveled on the inside. It is the area of this shoe
which represents the area excavated.



92



DRILLING FOR PLACER GOLD




DRILLING FOR PLACER GOLD 93

The casing is nearly always driven to gravel. If the first
joint does not reach, a second, and sometimes a third, is put
on. As soon as the first joint has been driven to head, the
driving cap is removed, the threads brushed off and greased
(being careful to use only graphite and linseed oil for the
purpose so as not to allow any oil to get into the bore hole,
K. D. Co.). The second joint is then put on, cinched tight,
the driving cap placed on that and the driving continued.
The depth driven at first usually varies from three to twelve
feet.

In driving, the stem on which the driving blocks have been
placed acts as the weight in a pile-driver. The weight of the
stem is about 800 Ibs. and the drop ranges from 28 to 36
inches.

After the casing has been driven as far as desired, the
driving blocks are removed, the stem is lowered into the
casing, the core is measured, water is poured in and the walk-
ing beams are set in motion. When the machine man
measures and reports the length of core to the panner, he
also reports the depth of the casing in the ground. The
core is measured in the following manner: The length of
connected casing is measured on the drill-stem and rope,
commencing at the bit. This point is marked in chalk.
The stem is then lowered into the hole, and the difference
between where the top of the casing is and where the mark on
the stem is, is the core. The core then is the material in the
casing. This is important and will be fully explained later.

While there is yet some core in the casing, the drill-stem
is removed and the sand-pump is placed in the hole. This
is a piece of 4-in. pipe about 8 ft. long, in which a rod or
plunger fits the pipe closely. At its lower end there is

HARRON, RICKARD MeCONE



94 DRILLING FOR PLACER GOLD

a valve. On raising the plunger suddenly, a vacuum is
formed and the material in the hole is forced in through the
valve at the bottom. This is repeated until all the ma-
terial is thought to be in the pump. The pump is then
reeled out of the hole, and its contents is caught by the
panner. The stem is then lowered into the casing, the core
is measured, the stem is hoisted, the driving blocks are put
on and the casing is driven again.

This is repeated for each foot of the hole until the desired
depth has been reached. The desired depth is generally
bedrock or the lower limit of a known pay-streak. The
depth to which the hole is sunk in bedrock depends upon the
occurrence of gold. Some bedrock carries gold for a con-
siderable depth. The hole is generally put down until no
colors are found in the pan. It may happen that the casing
has come on bedrock in such a way as to cross a seam. This
seam may be particularly rich and gold might come into a
number of pans after bedrock has been reached. When this
occurs, it is well to be wary of the results of that hole if it
gives a yield above the general average. The gold is plainly
coming from a seam and so we have no measure of the
volume of dirt from which it is coming. There is one way to
guard against this danger. When approaching bedrock,
use two or more small pans for receiving the concentrate
from each foot panned. The concentrate for, say, the first
27 ft. .is placed in a pan. On driving the 28th foot and pan-
ning, there is found to be more gold than usually comes with
bedrock. This is then put in a separate small pan, as is each
succeeding pan of concentrate; if there seems to be more
gold than usual, it is saved separately and the results of the
ground above bedrock and that below bedrock are then



DRILLING FOR PLACER GOLD 95

known. This is not often necessary, but it will save dis-
trust of the high returns, which sometimes appear in a hole
among a lot of other lower results, which are fairly close
together.

The hole being drilled as far as desired, the drill is placed
on the ground, the rope-socket taken from it and placed on
the pipe-jars. These pipe or pulling-jars consist of an iron
ram or boss on the end of a stem about four feet long. On
this stem is a threaded knocking-head with a square opening
through which the stem passes, up and down, in striking the
blow. The threaded knocking-head is screwed to the cas-
ing and the ram is drawn up so that it will strike against the
knocking-head when put in motion by the walking-beams.
The walking-beams are then set in motion and the jar of the
ram against the pipe causes it to be loosened and to be drawn
up. As the pipe comes up, the slack is taken by the runner.
When the top joint is removed from the ground, the machine
is stopped, the threaded knocking-head is removed and the
pipe-jars are pulled from the casing. The top joint is then
removed and the operation is repeated for each succeeding
joint.

When all of the joints are out of the ground, the drill-stem
is again put on the rope-socket, loaded into the bed of the
machine, the jacks removed from under the machine, the
engine thrown into gear for propelling mechanism and the
whole is moved to the next flag.

TREATMENT OF MATERIAL FROM THE HOLE

The material brought up by the sand-pump may be
treated in different ways. It may be caught in a pan held
over the sluice-box, the slime going to the sluice-box; it is



96 DRILLING FOR PLACER GOLD

then washed in the panning tub. It may be caught in the
pan, the slime going to the sluice-box as before, then washed
in a rocker, the material caught on the apron being panned
separately; or it may be dumped into the sluice-box and all
of it swept into the rocker, the concentrate being panned.

The second way seems to answer the purpose best. It
gives quickest results and is the easiest for the panner. It
uses a minimum of water, and at all times the water in the
tub is comparatively clear, thereby preventing the loss of
gold unavoidable when panning in thick water.

The apparatus required is a sluice -box about eight feet
long and 12 in. square in cross-section, a small rocker, pans
and panning tub.

Each foot is pumped and panned; the gold is estimated
carefully. The amount is then inserted on the log opposite
the foot from which it came. This is more fully explained
when describing the log-book. The gold is classed in three
sizes, 1, 2 and 3. Number 3 is the finest and consists of all
pieces which weigh less than one milligram. Number 2
gold would be any piece weighing one milligram or over, up
to four milligrams, and Number 1 is such that any piece
weighs over four milligrams.

As mentioned above, the concentrate from each washing
is put in a small pan, and, when the hole is completed, the
gold is amalgamated and put by itself. In special cases, we
would have more than one "pill", as explained already. The
gold is separated from the mercury by nitric acid and
thoroughly washed, dried, annealed and weighed. If the
drying is done in the annealing cup, there is no danger of loss
due to sputtering, but the addition of a few drops of alcohol
to the last wash water, when using the porcelain cups, pre-



DRILLING FOR PLACER GOLD 97

vents sputtering. From the weight of gold obtained, and
the volume of dirt from which it came is figured the value of
the ground immediately adjacent to the hole.

Not only the gold obtained from the pannings is recorded,
but the character of the gravels. This would include a note
on the size of particles and whether there was sand, clay or
cementing material present. This is ascertained by a close
examination of the screenings, as left in the hopper of the
rocker. Then, too, the panner carefully notices his con-
centrate and records anything of interest, such as the
amount of black sand, any gem stones, and the appearance
of amalgam. These are all recorded in the log-books, oppo-
site the foot in which they were found.

THE LOG BOOK

It is in the records that the engineer finds his data for
valuing ground. The log-book as kept by different men
varies, but for practical utility I have found the accompany-
ing to be best ; Table I is a page from a log-book as kept by
a panner. All linear dimensions are in feet and tenths.
At the head of the page is placed the number of the hole as
drilled and the number as recorded in the transit-book.
Following this is the name of the tract on which the hole
was drilled. In column "A", we have recorded the depth to
which the casing has been driven. Everything on the
same horizontal line as that refers to that foot in the section
of the ground. This is measured by the machineman and
recorded by the panner. In column "B", we have the
depth of core after driving. This is a measure of the amount
of material which has been forced into the pipe by the last
drive plus the core left in the pipe before driving. It gives



98 DRILLING FOR PLACER GOLD

the panner an idea of the kind of ground to expect and
occasionally it indicates the character of bedrock. In drill-
ground in which the bedrock is volcanic ash (such as that
at Oroville), a large core after a hard drive is a very good
sign of bedrock. Its importance, however, lies in the fact
that it acts as a check on the amount of material coming
into the pipe. Column "C" is also important. In it we
can see if the bit has been below the casing and at what
point. If we see that it has been below and has found an
abnormal amount of gold for that pumping we can be sure
that something was wrong some gold has run into the pipe.
In this hole, the bit is never below the casing except after
the casing has been driven 0.5 ft. into bedrock. The reason
for this is, that the machine-man is under orders to cease
drilling while there is yet 0.3 ft. of core in the casing. There
is only one reason for the bit to be below the casing; the
ground is so tight or so coarse that the casing will not drive
unless the ground is loosened below the casing. And in no
case where the ground is drilled below the casing should the
material be pumped before the casing is again driven deeper.
This core is to act as a plug to prevent any material from
outside the limits of the shoe from running into the casing.
Its length will depend on the ease with which the ground
runs. In sand, a larger core is required than in gravel.
The proper length of core to leave can be determined only
in the ground itself and will vary not only for different holes
but also for different depths in the same hole. This must
be regulated by the man in charge.

The length of core left in the pipe before driving should
always be such that only the right volume of material will be
forced into the casing. By the right amount is meant that



DRILLING FOR PLACER GOLD 99

amount which corresponds to the volume of a cylinder one
foot long and 7/^ in. diameter at the base. This amount,
when forced into the pipe, should be somewhat longer than
one foot, as it has been reduced at the base to a circle only
six inches in diameter. This cylinder, to have the same
volume as the one of larger cross -sect ion, not allowing for
the expansion due to the loosening of the gravel, would be
18.7 in. long, or 1.555 ft. But only in those cases where the
ground is classed as "very firm" does the length of core ap-
proach this value. (See column "B" for the following feet:
15-19 and 27-30).

In column "D" is placed the core after pumping, and its
importance in one way has been shown. Its further im-
portance will be indicated later. In column "E" is placed
the depth of the hole. It is obtained by subtracting the
core in "D" from the depth of the casing as seen in "A." It
is the least important of all, and is only retained as a con-
venience.

TABLE I

In column "F" are recorded the estimated amounts of
gold, which are classified as explained above and are re-
ported by weight, not by number of colors. For example:
3 7 means that seven milligrams of No. 3 gold was found in
that pan; 2 9 means nine milligrams of No. 2 gold, and I 18
indicates 18 milligrams of the largest size were in the pan.
This estimating of weights tells a great deal more than the
mere number of colors. It is remarkable how expert a man
will become in estimating the gold, especially in the smaller
sizes. In looking at the log-book one can immediately tell
how the ground is running and how many cents it will pan
per cubic yard. Each milligram of gold per running foot



100 DRILLING FOR PLACER GOLD



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DRILLING FOR PLACER GOLD 101

means that that foot corresponds* tc ground of a -Value of
6c. per cu. yd. For example, in the: 15th foot -the: patmer
recorded two milligrams of gold arid one immediatciy knows
that that corresponds to 12 -cent ground; in the 17th foot
there were 11 milligrams or that ground was 66-cent ground.

This value is obtained thus: Each running foot means
0.01 cu. yd. Therefore, if we get one milligram from 0.01
cu. yd., from a yard we should get 100 mg. ; and as a gram of
gold (as ordinarily found in the gravels of the San Joaquin
and Sacramento Valleys) is worth about 60c., 100 mg. is
worth six cents. This method of recording weights em-
phasizes the occurrence of pay-streaks much better than
that of recording colors only.

In column "G" is recorded the amount of material ob-
tained by pumping, as measured in the pan. It is a rough
check on the volume extracted and its use is shown later.
In column "H" is given the time of each pumping. It helps
to afford an idea of the stiffness of the ground by a measure
of the time it takes to drive, drill, and pump a foot. In
column "I" is recorded the character of the ground in regard
to its tightness. Ground is classed as "loose", "firm" and
"very firm." "Loose" ground is that which can be drilled
and pumped at the rate of one foot every 5 to 9 minutes;
"firm" ground would be such as required from 10 to 14
min. for the same operations, and "very firm" that which
required a longer time. In column "J" is recorded the for-
mation as passed through. This is classified under the
following heads : Clay, sand, cemented material, fine gravel,
medium gravel, coarse gravel and large boulders.

Under the head of remarks, almost anything important or
unusual is recorded. This would include the amount of



102 DRILLING FOR PLACER GOLD



-



TABLE II



Hole No, 2Q. - . C* W. J. Smith's Tract.

Commenced hole 7 a. m. 10-25-1904

Finished drilling 8 a. m. 10-26-1904

Finished pulling 9:47 a. m. 10-26-1904

Finished hole 10:05 a. m. 10-26-1904

Depth of hole 39 ft.

Depth to bedrock 35.5 ft.

Character of bedrock Soft white tuff, much slime

Depth of soil 4 ft.

Water level from surface .*.... 14 ft.

Total colors I 33 , 2 52 , 3 119 , 204

Gold in box - 3 4

Gold in tails - 3 4

Pay-streaks 8-18, 21, 22, 25-31, 34-38

Delays cause and length

Length of pipe No. 1 6.5 ....

2 6.1 12.6

3 4.8 17.4

4 5.3 22.7

5 5.7 28.4

6 5.6 34.0

7 5.1 39.1

Sand 5, 12, 20, 32

Clay ."

Cement

Fine gravel 6-8, 19, 21-24, 31, 33

Medium gravel 9-10, 25

Coarse gravel 11, 13, 18, 26-30, 34, 35

Loose gravel 5-10, 23-24, 31, 33

Firm gravel 11-15, 19-22, 25-26, 32, 34

Very firm gravel 16-18, 27-30, 35

Remarks. A great deal of sand occurs mixed with gravels and in
places there is enough water to cause the ground to run.

Calculated volume 0.38 cu. yd.

Volume by cores 0.45 cu. yd.



DRILLING FOR PLACER GOLD 103

black sand, the occurrence of amalgam, etc. Here also
would be mentioned anything peculiar about the gold, such
as its lightness, both in weight and color, and the occurrence
of flour gold. The delays, with their causes and lengths,
would also be stated here.

TABLE II

Table II is the summary which follows each hole. It is
self-explanatory. The water-level is measured during, or
after, the casing is pulled. If there is no danger of the
ground caving, this is left till but one joint remains in the
ground. If there is any danger of the ground caving, the
measuring is done after each joint is pulled.

I think I have shown how the drill and its record can be
made to answer all of the first four questions, with the ex-
ception of the value of the land and the contour of the bed-
rock. These are obtained by the use of the records in the
log-book with those obtained in making the surveys. By
running a line of levels over the holes, and using the depth
to bedrock as found in the log-book, the contours of the
bedrock can be estimated.

CALCULATING VALUES

In figuring the value of the ground, one must be certain
of the volume of material from which each sample came.
It is the lack of this knowledge which has caused most of
the errors made in valuing ground by the method of boring
holes. The volume of a hole excavated as described is not
that of the inside of the casing, but is the volume of a cylin-
der whose length is the distance from the surface to bed-
rock, or as deep as pay goes, and the area of whose base is



104



DRILLING FOR PLACER GOLD



Fig. 1.



Fig 3.




m

m



Fig. 1 represents the casing after the core has been drilled and the
drillings pumped out. The blocks are then put on and the casing
driven one foot.

Fig. 2 represents the pipe with the core in it just after driving, and
before drilling.

Fig. 3 is the same after the core has been drilled and dumped, and the
casing made ready for the next drive.



DRILLING FOR PLACER GOLD 105

the area of a circle 7.5 in. diameter; that is, the diameter of
the shoe. If no ground has run into the pipe, we can use
what is called Radford's "Keystone" factor; that is, 0.27.
This is used in the following way: Multiply the depth
in feet by 0.27 to get the volume in cubic feet. To reduce
to cubic yards, divide by 27. To simplify matters, divide
the depth of the hole by 100 to get the volume in cubic
yards. This factor was obtained by experiment in one
case, and apparently does not take into consideration the
possibility of any other material, not belonging to that
cylinder, running in. This ground that has run into the
pipe carries gold and must be taken into consideration in
figuring the volume from which the sample came.*

The weight of the gold from the hole in Table I was 184
mg., or approximately 1 1.04c. ; the volume for 38 ft., accord-
ing to Radford's "Keystone" factor, was 0.38 cu. yd. ; there-
fore, the value of a cubic yard is 29.05 cents.

*[No attempt is made to weigh or measure the volume of material actually
excavated from the bore hole. Such a method would introduce many elements
which would usually make the results wholly unreliable. As a matter of fact some good
engineers have gone wrong at this point by comparing the value of the gold obtained
from the test with the volume of the material delivered in the sluice box by the sand
pump. The reason why such a method would be unreliable is, that when the material
encountered by the drill, drive shoe or sand pump has been disturbed, mixed with water
and allowed to settle, it will not give the same cubic volume which it originally occupied.
There would be a change in the proportion of water contained and the volume would
also be changed by a rearranging of the particles, especially if the drillings consisted in
part of clay and in part of sand. A bucket full of fine clay may be mixed with a bushel
of coarse sand and gravel and the whole put in a bushel measure. In certain soils, a post
hole may be bored, a large-sized post inserted and all the borings tamped in about it
without more than filling the hole. In making these alluvial tests the strata may
change from dry to wet or the material from clay to sand, or from fine to coarse sand
many times between surface and bedrock, so that the volume tests or volume method of
valuing the ground is wholly unreliable. The fact that the drillings actually taken from
100 feet of test hole measure more or measure less than that which is represented by the
core for that depth does not at all indicate whether the drill has excavated more or less
than the area of the drive shoe.

From all the above, it will be clearly apparent that in making the tests everything de-
pends upon having tools and appliances that will excavate the exact volume represented
by the drive shoe from surface to bedrock, or at least while passing through that part of
the distance in which the gold is to be found. Making hole to bedrock is not making a
test. If, in making the hole, some of the material is driven off into the side of the bore
hole the test will show too little gold. If, on the other hand, the surrounding material
with its gold is drawn into the bore hole the amount recovered will be too great.
Keystone Driller Company.]



106 DRILLING FOR PLACER GOLD

In looking at the cores in column "B", it is seen that they
differ for the different formations drilled. For example,
compare the cores in columns "B", "C" and "D" for the
following feet with those of any of the others : 11,12,13,19,
20, 21, 22, 30, 31 and 32. In "B" they are larger than
ordinary, and in places in "D" we see that the core after
pumping is greater than before. There is only one conclu-
sion; the ground is running into the pipe and here we are
getting more than is represented by a cylinder 38 ft. long and
7.5 in. diameter. This must increase the volume, and it
certainly increases the gold obtained, as can be seen by
looking at column "F." This increase in volume must be
taken into account or else the increase in the amount of
the gold will give a false return.

By a careful use of the core-lengths recorded and the
volumes given in "G", the volume of the incoming ground is
obtained thus: Opposite the llth foot, the core after pump-
ing is 0.7 ft. and before it was only 0.5 ft. ; clearly a running-
in of 0.2 ft. Then, too, in column "G" we get one pan of
material where we have only been getting 0.75 pan before.
That shows that a little more was pumped than was to be
expected by the core after driving.

Again in the 12th foot we have a running-in of 0.5 ft.
after pumping, and to begin with we had 2.9 ft. core where
we did not look for more than 2.2 ft. ; therefore, for this foot
alone, we have a running-in of 1.2 ft. By going down all of
the cores we see that there has been a running-in of about
5 ft. Then by looking at the pans we see a greater amount
of material than was to be expected from the cores. For this
hole, this amounts to about another two feet ; that makes an
extra 7 ft., or the hole corresponds to a depth of 45 ft. and



DRILLING FOR PLACER GOLD 107

the volume would be 0.45 cu. yd. Using this as our basis of
valuation of the ground, we get an average of 24. 5c. per
yard. This is about 15 per cent lower than the yield we
found above and I think is much nearer t{ie true value.
Such a difference would destroy the valuation of a large
deposit.

Of course, all holes do not contain running ground and
where they do not, there is not the need of making these
modifications. For this class of ground, this form of log-
book seems to record the facts better than a simpler type.
As one cannot tell when running ground is to be encountered,
this form of notes should be used all the time.*

FINAL CALCULATIONS

The average value of the ground for the whole area is
obtained in the following way: Multiply the average yield
of the ground for each hole by its depth in feet ; add these
products and divide the sum by the sum of the depths.
The volume is obtained as soon as the area is known and
the average depth over that area. The gross value of the

*The "Keystone Rule" for computing values is as follows:

Multiply the value of the gold (in cents) by 100 and divide by the number of
feet drilled the result is the value of gold per cubic yard.

After experimenting with larger and smaller sizes we have selected the 6" test tube as
the smallest which will give reliable results. This tube has a (nominal) inside diameter
of 6" and is shod at its lower end with a tempered steel shoe, the cutting edge of which
when new and sharp is 7H inches in diameter. It is the size of the shoe and not the bore
of the pipe which should be used as basis for computing values. The area of this 7^*
shoe at its cutting edge is about 3-10 of a square foot. Hence for every foot in depth
there will have been excavated 3-10 of a cubic foot, or (since there are 27 cu. ft. in a cubic
yard) 3-270 or 1-90 of a cubic yard. In operation, however, the cutting edge of the
shoe may and does become more or less battered or bruised (by contact with boulders,
etc.), so that>s practice and observation have shown, it is more nearly correct to subtract
from this amount about 1-10 which would make the amount excavated from each part
drilled just about 1-100 of a cubic yard, or one cubic yard for each 100 ft. of test hole.

An Example and Answer by the Keystone Rule.

Suppose the test tube has been put down 38 ft. Total amount recovered from drill-
ings say 12c. Multiply the number of feet (38) by the Keystone Factor (1-100) and we
have as the amount of the material excavated 38-100 of a cubic yard. Then if 38-100 of
a cubic yard produces 12c worth of gold, the amount obtainable from the whole cubic
yard would be 100-38 of 12c or 31 6-10c (nearly) per cubic yard.



108 DRILLING FOR PLACER GOLD




Moving with derrick up



DRILLING FOR PLACER GOLD 109

deposit is then found by multiplying the value in cents per
yard by the total number of yards. The net value is
obtained by subtracting from the gross value the cost of
the land, the cost of working, and the loss in tailing. These
will differ under different conditions and in different parts
of the country.

A machine will make from 12 to 40 ft. per day; it is
impossible to give an average, as it varies in different parts

of the State.

VALUE OF TESTS*

Drilling followed by dredging, as at Oroville, has shown
that only about 75% of the yield shown by drilling has been
recovered. To test the value of these tests one acre was
drilled with 23 holes and the dredging returns produced
bullion worth 95% of that shown by the drilling results.
In another case, a boat dredged only about 35% of the gold
as shown by the drilling, but in this case there were only
two holes per acre. It is plainly seen that the more numer-
ous the holes, the more accurate is the sampling. With
care and a careful superintendence of the drilling, there is
no reason why these results should not be fairly accurate;
they can always be checked by the sinking of shafts pre-
paratory to the commencement of actual dredging.

(End of Mr. Stines' article.)

*As to prospecting ground with drills, it is said that the Oroville experience has shown
a yield by dredging from 70 to 85 per cent of that given by drilling tests. It is just such
statements as this that are useless, although apparently businesslike. The value of a
series of drill-holes as indicating the richness of a tract of gravel cannot be gauged by any
empirical formula. It is as absurd as the practice of timid engineers who cut their
estimates of ore in two or deduct a certain fixed percentage from their calculations, so as
to be safe. In the case of drilling before dredging, the result is reliable according to the
number of holes, the distribution of them, the care taken in the work and, above every-
thing, the personal factor. Such work carefully done and checked at each stage by a
man of experience and integrity needs no big discounting, while that accomplished by an
unreliable driller or a careless novice is worse than worthless. No fixed percentage
covers the varying conditions surrounding an engineering operation.

In the early days of dredging it was the custom to test 200 acres with 10 drill-holes;
nowadays one hole to two acres is not uncommon. When results indicate that the



110 DRILLING FOR PLACER GOLD

gravel is of varying depth, that there are irregular channels or that the ground is spotty,
it is not unusual to put down as many as one to three holes per acre, especially where no
adjoining workings exist, such as throw light on any anomalous results from the chilling.
The cost is a limiting factor, for each hole costs $60.00 to $100.00 in ground of any
considerable depth.

It is generally assumed that the results given by shaft-sinking are more reliable than
those from drill-holes; as a rule this is true, but the comparison too often smacks of the
old idea that a mill-run is more trustworthy than the sampling of ore in a mine. It de-
pends upon how it is done, with this proviso, that the more men needed to carry out an
operation of sampling, the greater the opportunity for error, intentional or unintentional.
A shaft gives better opportunity for examining the nature of the successive layers of
gravel and other conditions that bear upon the subsequent working of the ground.
Careful measurements are imperative; sometimes it is not practicable to hold the same
diameter of shaft all the way down, and in running ground one has to resort to timbering;
these factors affect the cross-sectional area and must be carefully noted in any calcula-
tions. Moreover, instances are known where shaft results have been seriously vitiated
by the fact that the particles of gold have fallen to the bottom, with the water, so that
the upper layers of gravel appeared worthless, while that immediately above bedrock
was excessively enriched* Great caution, bred of experience, is required to make an
accurate test. Editorial from Mining and Scientific Press for February 3, 1906.

ACCURACY OF THE TESTS

This has been proved by experiment in many ways, the most conclusive of which was
made at Oroville, California where there are now (1907) about 40 large dredges at
work upon large areas of ground all assayed in advance with our machines. A test
tube was first sunk in the usual way with one of our machines. The contents of the test
hole was computed, and the amount of gold washed out of it weighed carefully. Then
to prove the accuracy of the results thus obtained, and without moving the test tube, a
three-foot shaft was sunk around it, the sand and gravel washed, the gold taken out of it
and weighed. The results of the two tests were then carefully compared and it was
found that they tallied to within three to five per cent the tube test giving from three
to five per cent less gold than the shaft excavated by hand. The difference was easily
accounted for by the uneven surface of the hand-made shaft, it being impossible to ex-
cavate by hand to the exact size. The tube test as made with our machine was there-
fore considered the more accurate.

In other cases, where the gold was confidently believed to exist and none was found
with the test tube driven, small quantities of gold dust were weighed and dropped into
the tube when the hole was about 25 feet deep. The gold dust was then thoroughly
mixed by cutting up several feet of material with the drilling tool and driving the pipe
that distance, but not to bedrock. The cut-up materials were then recovered with the
vacuum sand pump and panned. The gold recovered was dried and weighed and cor-
responded within a very small percentage to the respective amounts put in. In this
way, in one particular instance (near Marinsk, Siberia), it was proved that the hand-
made shafts previously excavated by the natives, and which had assayed "high values",
had been most cleverly "salted" by the owners for selling purposes. The discovery of
the trick spoiled the sale and resulted in the cancellation of the order for about a quarter
of a million dollars' worth of dredging machinery, but we had the sincere thanks of the
purchasers of our machines as it saved them wasting a vast amount of money. Our
tests proved the ground wholly barren. Keystone Driller Company.



PROSPECTING FOR COPPER WITH
CHURN DRILLS

Written for The Mining and Scientific Press (Issue of
Dec. 29, 1906) by F. S. Pheby

Believing that the great horizontal ore-bodies of the Ely
district could be more cheaply and expeditiously tested by
the use of the drill rather than through the usual tedious
and expensive method of shaft-sinking, the Ely Central
Copper Company purchased two drills, manufactured by
the Keystone Driller Company, of Beaver Falls, Pennsyl-
vania. These drills were hauled from Cherry Creek to the
mines, a distance of 60 miles.

These machines are type No. 3 and weigh 12,000 pounds
each. A complete outfit of tools and equipment for recover-
ing any parts of the drills lost in boring the holes were
included in the order.

The first drill was installed on the property in August,
and we had a hole completed to a depth of 308 feet within
23 days, although but one shift was engaged in this work.
It is far more economical in wood and water to keep the drills
running continuously with three shifts. More than three
times the sinking can be done in the same number of days,
as steaming up in the morning generally comes out of the
one shift. The drill averaged 13.3 feet per shift for the
23 shifts, but if shut-downs were deducted, the drill averaged
19.6 feet per shift of actual operation.

We have found in all our work that casing is necessary in
every hole. At times we have sunk 200 feet without casing,
but to go deeper, casing was necessary, which meant that the

111



112 DRILLING FOR PLACER GOLD




DRILLING FOR PLACER GOLD 113

hole had to be reamed out at an expense of more than the
original cost of the hole for the 200 feet. I caution anyone
contemplating the purchase of a drill, to provide 7% casing
for one-third the depth contemplated, 5^g casing for two-
thirds the depth, and 4^ casing for full depth. This we
had not done, and probably 25% has been added to the cost
of each hole, working without sufficient casing. Trouble
may not be encountered in several hundred feet, but a soft
stratum of ten feet will require the casing for the entire hole.

We soon learned that the wear and tear on the drilling
cable was severe. Under ordinary circumstances, each rope
is safe for 1500 feet of drilling. When we appreciated that
our ropes were deteriorating, an order was placed at once.
By October 1st the cable had not arrived, and we were com-
pelled to order by express from Ohio a coil of rope weighing
1850 pounds. With each drill, two ropes of the same length
as the depth of the hole contemplated should be ordered.

Water is required both for the boiler and for diluting the
drillings so that the sand pump may bail them. The greater
quantity is required for the boiler. This item of expense is
local with each hole. It is advisable to haul water in a good
wagon-tank, as the drills may be moved many times, and
the cost of pipe might be greater than the cost of hauling.
A drill-man and helper are required on each shift, the former
receiving $4.00 for eight hours' work and the latter $3.25.
The items of fuel and water are wholly relative, but will be
given in our particular case, and may be taken as an average
for this district. Figures are for 1906.



114 DRILLING FOR PLACER GOLD

The following is the tabulated costs for a certain hole
which we have taken as an average :

Shifts of sinking (eight hours each) 23 days

Depth of hole 308 feet

One drill-man, wages $ 82 . 69

One helper and assistants while handling casing ; 81 . 08

% cord of wood each shift, at $4.50 per cord 77 . 51

12 bbl. water at $6.50 for hauling, 8 days 52 . 00

12 bbl. per day (when running two rigs) 15 days 48. 75

Coal and oil 7 . 60

Miscellaneous charges 12 . 20

Superintendence 50 . 00



Cost of 308-foot hole $411 . 83

Cost per foot $ 1 .33

Some water was encountered in this hole, and I may say
roughly that a two-compartment shaft for the same depth
with equipment, would have cost about $12,000, or $40.00
per foot.

The question has often been raised concerning the
character and accuracy of the sample obtained from this
work. With small rich veins there may be an objection to
the use of drills, but in orebodies like those found at Ely,
I believe as good a sample can only be taken with great care.
Most of the sludge or drillings will pass a 20-mesh screen,
and a good method is to provide a large box with a capacity
equal to several screw-lengths. I might say that a screw is
three feet long, and when fed out, the clamps are changed
on the rope, and the hole bailed, or sand-pumped. By
settling and decanting the water, the entire product of the
hole may be saved and sampled. In ordinary practice, it is
sufficient to dip a sample from the box and pour the same
into a box partitioned off in compartments about the size of
a common brick. This sample, when dried off in the sun, is



DRILLING FOR PLACER GOLD 115

compact enough to be sampled by chipping, and can be
shipped and carried about without breaking.

In a hole carried down without- casing, there is danger of
knocking down particles from the upper portions of the hole.
This will vitiate the sample, but the harm done is more
theoretical than actual. As is well known, the orebodies of
Ely are the impregnation of a great stockwork of porphyry,
and an orebody of much value must be a hundred or more
feet thick. While actually in ore, the sampling must be
done with extreme care, but often the hole, all or in part,
may be in barren country rock, and only a knowledge of the
formation penetrated is desired.

The best test, where not in ore, is obtained by panning the
sample. This concentrates the coarse particles, which are
clear to the eye if a magnifying glass of low power is used.
In oxidized formations some doubt often arises as to whether
the drillings are composed of porphyry or limestone. A
small bottle of dilute hydrochloric acid will soon settle this
question with entire satisfaction. We have made a prac-
tice of saving a sample of each formation penetrated, in four-
ounce bottles. This gives a clear picture of the hole, and is
valuable for future reference.

Our drills are provided with traction gears, and may be
moved at will over the roughest ground. This saves the
expense and trouble of procuring teams. The winter
weather is severe for outside work, and sectional houses, so
made as to be readily knocked down and moved, have been
constructed to enclose the drills, and within these houses
the men work in comfort.



116 DRILLING FOR PLACER GOLD

A drill of this size is light for holes of greater depth than
500 feet. The size recommended is a No. 5, good for 1200
feet, and the cost of the. same with traction gear is about
$2500 laid down at Ely. Should five holes of 500 feet each
be sunk, the cost of equipment per hole will be $500, about
the price of a good whim outfit. The cost of $1.50 per foot
is so much cheaper than any shaft work as not to be com-
parable. Water does not retard the work of drilling; in
fact, it is a benefit.

I can heartily recommend the use of these drills for pros-
pecting in this region. Apart from the cost per foot, the
time in which a good working knowledge of the ground can
be obtained, is a great factor. The sample is quite as good
as a core, and most ground can be penetrated at 25% of the
cost incurred with a diamond drill; while the expense of
equipment will not exceed 30% that of the diamond-drilling
outfit.



BLASTING TIGHT PLACERS
BEFORE DREDGING

By Oliver B. Finn
From the Engineering and Mining Journal of July 7, 1904

Gold dredging has made such rapid strides of late and
there is such a widespread interest in this branch of mining
that I venture to contribute a detailed account of the way
in which a Keystone driller was used by me in California to
loosen, by blasting, a very tight gravel deposit, preparatory
to dredging. There is a great difference between "cemented
gravel" and "tight gravel." A truly cemented gravel is not
a dredging proposition, while the tightest possible gravel,
where there is no cement, can be made easy working by the
following method of blasting :




Section of Placer.



The deposits in question were practically a solid mass of
cobbles, the voids being filled with a heavy sand, forming a
mass so tight that every conceivable method of manipulat-
ing the dredge resulted in constant breakages and a failure
to dig sufficient gravel to yield a profit. The dredge was of

117



118 DRILLING FOR PLACER GOLD




On the Yukon



DRILLING FOR PLACER GOLD 119

the elevator type, much too light in construction for un-
blasted tight ground. The results of an eight months'
run showed the average load of the buckets to be only one-
fourth of their capacity, while much of the time many of
them ran empty, and 50 per cent of the working time was
lost in shut-downs for repairs, thus reducing the work done
by the dredge to one-eighth of its capacity. The repairs
had cost thousands of dollars ; and although the ground con-
tained good dredging values, the undertaking was a total
failure, until finally blasting was adopted. It was proposed
to blast this ground, using a 6-in. churn drill to sink wells
(in the bank ahead of the dredge) in which to place the
explosives. As the procedure was entirely new, a number of
months were wasted before the owners of the dredge would
supply a drill, but being prevailed upon to do so, upon arrival
of it, a line of holes was driven to bedrock about 20 ft. back
from the working face; the holes 50 ft. apart, and each suc-
ceeding line of them 50 ft. farther back. The holes in each
line "staggered" with those of the next. Each hole was
blasted as soon as completed. Black powder was found
useless, since, owing to the tightness of the ground, the
whole force of the explosion was spent in blowing out the
tamping and water. Various sizes and strengths of explo-
sives resulted in the selection of 30 Ibs. of 80 per cent nitro-
glycerine dynamite. This was put up to order at the factory
in tin cans 3 ft. long and 4.5 in. in diameter, with a wire bale
fastened to the inside of the can so as to make a smooth
cartridge readily inserted into the well through the inside of
the casing. Before inserting the explosives, the well casing
was drawn up about 4 ft. from bedrock; the casing could
not be entirely drawn before loading the hole, as the hole



120 DRILL ING FOR PLACER GOLD




Method of Blasting.



DRILLING FOR PLACER GOLD 121

would be partially filled by caving in from the sides. Elec-
tric exploders were used, two to each charge; the second one
as a precaution against a missed shot.

As the "pipe jar," which is the best device for pulling up
the casing, practically closed the top of the casing, the
electric wires had to be kept within reach during the draw-
ing of the balance of the casing by fastening them to a stick
one inch square, which reached from the cartridge bale to
the surface of the ground when the cartridge was in place,
care being taken to have sufficient casing above ground to
prevent the "pipe jar" from striking the upper end of the
stick. The stick also served the purpose of supporting the
charge, when lowering it into the well and preventing any
strain upon the electric wires. When the charge had been
carefully lowered into place, the "pipe jar" was replaced and
all casing withdrawn. The hole was then filled with sand,
and the drill moved to the place for the next hole. The
wires were connected with the dynamo upon the dredge, and
the charge exploded.

The explosion did not displace any of the bank, but the
shock and vibration were such as to loosen the cobbles with-
out disturbing their original relative position, excepting, of
course, those close to the shot. Each explosion was effec-
tive far beyond its allotted area, so that the spacing of the
holes could be gradually increased to as much as 100 ft.
apart.

By saving the gold from the drillings of each hole, this
method served the double purpose of blasting and testing.

This preparation of the ground resulted in the buckets
running full to overflowing continuously, and there was no
occasion for shut-downs, except for clean-up of gold and oil-



122 DRILLING FOR PLACER GOLD




Prospecting in Russia

ing the machinery; notwithstanding, the machine was
practically a wreck from previous hard usage. In other
words, the capacity or output was increased eightfold, and
the expense for repairs reduced to that of normal wear and
tear. In this way many total failures could be turned into
successes, and the necessity avoided of either giving up the
entire project or supplanting a dredge otherwise too light
for the work with a heavier and more expensive one.

The average cost of the blasting was not over 0.5c. per
cubic yard. Where ground is at all tight and the buckets do
not easily fill, I would advocate blasting of ground, even for
the most powerful machine that could be built; since it is
evident that a very small outlay in this direction would be
saved many times over in power expended on the bucket
line and in lengthening the life of all wearing parts, to say
nothing of the increased capacity of the dredge.

|End of Mr. Finn's article]



PART III

MINERAL PROSPECTING
MACHINERY

^J^pTl MMfm

iKEYSTONI



BY
R. M. DOWNIE

General Manager, Chief of the Engineering
Department for Forty Years and Founder of
the Keystone Driller Company in April, 1882.



MINERAL PROSPECTING MACHINERY

By R. M. Downie

General Manager, Chief of the Engineering Department for Forty Years and
Founder of the Keystone Driller Company in April, 1882

CORE DRILLS

We have it upon the authority of its Maker that "the
earth is full of riches." Experience has proved this state-
ment true, and the machinery herein described has been
planned and perfected for the purpose of exploring for it.

New store bins of wealth are being constantly discovered
in all parts of the world and there seems to be really no limit
to them. No section or country has, or ever can have, a
monopoly of mineral wealth. The reason some portions
seem to have more than others is frequently because the
people of those localities have the enterprise to investigate
and develop what they have.

The older rocks and their conglomerates carry the
precious metals ; the newer contain zinc, lead and iron ; and
those of more recent formation contain oil, asphaltum, gas,
coal, fire-clay, etc. The drill is the key that unlocks all these
treasures coffers whose robbing wrongs no one.

Prospecting Drills in general are made to operate upon
two well known general principles. The older and best
known of these is the Percussion Drill, which penetrates the
earth by a succession of blows with a cutting chisel. This is
the cheapest known method of drilling, and generally the
quickest and surest particularly for deep borings. Such a
drill cuts up the material in its path ; but with the following
exceptions, does not take out a core or solid section of the
strata. The Keystone Percussion Core Drill can be used on

124



DRILLING FOR PLACER GOLD 125

any of our machines without any change in the operating
machinery. This combination makes an ideal outfit for
prospecting coal measures, etc. The regular solid percus-
sion drill bit can be used until the mineralized stratum is
reached. At this point, it and the solid drill stem used with
it can be taken off and, in their place, the Core Bit substi-
tuted and operated without any other change. This Per-
cussion Core Bit is made in several forms to suit different
kinds of rock. The joint for screwed connection by which it
is attached to the Rope Socket or Jars), is made to fit any
drilling tools of our manufacture and can, if the size is fur-
nished to us, be made to fit the joints of any other make of
machine. It and its operation are fully described in a
catalog, which will be mailed upon application.

The other general form of prospecting drill is the "Revolv-
ing Core Drill", which operates by being revolved like a
wood auger. It is made in three different forms, all of which
act on the same general principle. The first and most
common form of it is the diamond drill. It is made by in-
serting sharp cornered diamonds in the thickened end of a
tube. These diamonds act somewhat like the teeth of a saw,
and in their revolution, cut or scrape a circular channel,
leaving in the center a "core."

A second form of the revolving core drill is made of steel
or other metal ^to escape the expense of the diamonds,), and
consists of a series of saw-tooth points. It operates by
scraping out a circular channel about a center or core. It
works fairly well in formations which are soft and devoid
of grit; but in any material hard enough to make a grind-
stone the points of the teeth are immediately ground off and
operations cease until the teeth are renewed.



126 DRILLING FOR PLACER GOLD

A third form, designed to avoid the expense of diamonds
and the wearing of the steel teeth, operates to cut the chan-
nel by revolving the tube upon a layer of chilled steel shot
introduced constantly in the bottom of the bore-hole. But,
except where the material is devoid of crevices, this latter
form has met with but little success even in getting the hole
down. Other difficulties are noted below.

With all these three forms of revolving core drill, and
when the rock is suitable and seamless, the core remains
within the revolving tube still attached to the bottom of the
bore-hole until it is from one to six feet long. If this core is
not destroyed in the operation, a "core catcher" grips it near
the bottom, breaks it loose from its anchorage and brings it
to the surface for examination. During the process of drill-
ing with the revolving core drill, in order to wash away the
cuttings, prevent gumming, and in order also to keep the
diamonds, teeth or shot, as the case may be, from being
heated, burned or torn from their settings, a stream of water
is constantly forced down the hollow drill stem by a pump.
The cuttings are very finely pulverized and are generally
washed up the outside of the drill or flow away beyond re-
covery through openings in the rock. Thus, the entire re-
sult obtained by such a drill is summed up in the core.

Allow us to say at the outset that we do not manufacture
any form of revolving core drill. We refer to them here
merely for the purpose of pointing out the peculiar condi-
tions under which favorable results may be expected from
them. The only forms of core drill which we make are
operated by means of a cable with short up-and-down blows
and are usable interchangeably with the regular percussion
drills described at length in this catalog. Neither can



DRILLING FOR PLACER GOLD 127

these revolving core drills be operated by our machine with-
out the addition of revolving mechanism and pumps for
forcing water down the hollow drill rods. The foregoing
remarks are introduced solely for the purpose of pointing
out the difference and explaining exactly what we do pro-
duce. This will save written correspondence and enable
intending prospectors to intelligently decide what sort of
machine and appliances are best suited for the work to be
accomplished.

Where the natural conditions exist which allow the core
drill to be operated and which permit the core to be cer-
tainly recovered, there is nothing more accurate or satis-
factory. It shows the texture, stratification, laminations
and dip of the rock in undisturbed section; but there are
conditions under which it is wholly useless in any form.

It is a good and sound business policy to sell a customer
exactly what he needs and machinery and tools which will
perform with certainty and exactness the work desired.
This can be accomplished only by making the customer
fully acquainted beforehand with all the conditions of suc-
cess and by guarding against disappointment by pointing
out also what can not be done or expected. Hence, we
pledge our customers that we will not, under any cir-
cumstances, knowingly sell them that which will not meet
their requirements in the best possible way. Therefore,
we ask prospective customers to inform us fully and con-
cisely what they wish to do and if, as sometimes happens,
we do not make the machinery and tools best suited to their
requirements we will say so, frankly, and refer them to the
makers of that which we believe will do it. If a positive
order comes to us for goods listed, without any explanation,

HARROW, RICKARO * MeCONE



128 DRILLING FOR PLACER GOLD

we take it for granted that the customer knows his business,
and act accordingly.

But we wish it understood, (1) that we have every
facility for correspondence, and (2) those in charge of our
several departments are men who have had in the field a
wide practical experience in the operation of the machines.
We can therefore advise prospective purchasers with an
"assurance born of a knowledge of having done it."

It goes without saying that information imparted to us for
the purpose of adjusting the machinery to the work required
is considered confidential and in no case divulged.

THINGS WHICH CANNOT BE DONE WITH A
REVOLVING CORE DRILL

Before proceeding to a description of our machinery, its
various uses and plans of operation, let us briefly note some
things which cannot be done successfully with a core drill.

1. A hole cannot be made through sand, gravel and
boulders because the loose formations will immediately
close up the bore-hole upon the withdrawal of the drilling
tool.

2. With a core drill a casing cannot be inserted to keep out
the loose formations because it provides no means for driv-
ing the pipe or breaking up the boulders ahead of it. Of
course no samples or core can be taken out of such forma-
tions with a core drill, except what may be washed up the
outside of the tool ; and even the material which might be
thus recovered leaves the operator to guess whether it comes
from the bottom of the bore-hole or has been dislodged from
the sides of the well by the upward rush of the water.



DRILLING FOR PLACER GOLD 129

3. A revolving core drill will not with any precision or
certainty, go through broken, seamy rock; and it is wholly
inoperative among boulders. The hollow shaft of the
drill does not fit the bore-hole closely, and hence it may be
easily deflected by a hard surface, like a gimlet diverted by a
nail or knot; or it may seek to follow a soft lead or fissure.
Then there is nothing in the principle of its operation to
draw the drill back to a straight line if such deflection once
takes place; and hence a slight departure from a right line
will be cumulative as depth is gained, until the hole is
presently too crooked to allow any further progress. It is
next to impossible to straighten a hole with a revolving core
drill when once deflected ; but should this occur with a per-
cussion drill the remedy is very simple. On the principle
that a suspended weight tends to point perpendicularly from
its point of support the gravity percussion drill constantly
seeks to retain or regain the vertical.

4. Where horizontal cleavages are present in the rock, a
continuous core cannot usually be recovered by the revolv-
ing core drill; e.g., if a portion of the core becomes detached
from its anchorage by a lateral cleft in the rock, it starts
whirling with the core barrel. It is thus ground endwise
under the water pressure against the part yet anchored,
wearing away both itself and the part remaining fixed to
the bottom. The materials thus ground off are washed
down and out and lost. For this reason an accurate test of a
soft coal vein, for example, cannot be made with a revolving
core drill. Such veins are always full of cleavages and, the
material being soft, the core is very fragile, easily jarred
loose and broken off and readily ground up. True, a sample
piece of the core may be recovered but, since the amount



130 DRILLING FOR PLACER GOLD

worn off is wholly uncertain, the test for accurate thickness,
or even of the general composition of the vein, cannot be
made. At least the result would lack that certainty which
would justify the expense of shafting. The cuttings and
grindings, wholly or in part, may be washed away without
being recovered at the surface, or may be so finely pulver-
ized that, in a deep hole, they will float in the water unob-
served. The same difficulties are met with in testing for
granulous iron ore, lead, zinc and such minerals. These
latter minerals usually occur in broken formations.

The Percussion Core Drill was expressly designed to over-
come the above difficulties. In it the core barrel slips down
over and protects the core as fast as made, and, since it does
not revolve, it will not grind up the core, but will receive and
retain it in the exact order of its production. Therefore with
it a core can be recovered from a much softer and more
broken formation than with any other form of core drill
made.

5. A large hole cannot practically be made with the re-
volving core drill. The usual size of the core taken out is
from 1 to 1% inches in diameter. Should a mud vein, a
caving formation of clay or sand be found beyond the first
rock, the smallness of the hole will not allow a casing to be
inserted that further depth may be attained. On the other
hand the large hole made with the percussion drill allows
for such reductions.

6. A revolving core drill cannot be operated without
abundance of water. A constant stream must be forced
down the hollow drill rod. In rare cases this water may
return to the surface for re-use; but even so it will be
adulterated by washings from the sides of the well. Usually



DRILLING FOR PLACER GOLD 131

it flows off through the fissures and is lost, carrying with it
all the fine cuttings.

7. A revolving diamond core drill cannot be operated
successfully without a skilled lapidary to re-cut and re-set
the worn and loosened diamonds. The loss of a diamond is
not only serious in itself, but it may cut the remaining
points and destroy them before the loss is discovered.

8. The revolving core drill is operated by means of a pipe
in threaded sections which run from the surface to the
bottom. In operation this pipe must be jointed and un-
jointed every time the drill is put in or taken out. In deep
wells this operation becomes very slow and tedious. On
the other hand, the percussion drill, including our form of
core drill, is operated by a stout manila cable fed off a geared
reel as depth is attained. To lower the cable drill or draw
it from a well of any depth is but the work of a few moments.
The sand pumps are operated in the same way. It is true
that, as a rule, the percussion drill must be withdrawn more
frequently than the core drill say at least every four or six
feet while a core drill may be run somewhat further than
this distance without removal. But in mineral prospecting
it is always an advantage, (no matter which kind of a drill is
used), to run only short distances without examination of
the findings.

9. What we have said above regarding the "revolving
diamond core drill" is true also of the core drills employing
chilled shot for the cutting. In the latter drills the cutting
is done by means of a thick hollow tube, the end of which
rides upon and presses the chilled shot into the opposing
rock. If an open crevice be found, no matter how small, the
operator must feed in enough shot to fill the crevice or



132 DRILLING FOR PLACER GOLD

abandon the hole. Also if a seam be found that is filled
with mud or joint clay, the shot is forced off into it in
greater or smaller quantities. In revolution the hollow drill
rod is likely to become locked to the standing core, break it
loose and grind it up. As a matter of fact, no matter what
sort of revolving core drill is used, a continuous section of
core is not recoverable, except in hard rock, void of seams.
But this does not apply to the percussion core drills de-
scribed in Catalog No. 2-B.

These adverse contingencies, with others which they sug-
gest, limit the legitimate and profitable use of revolving core
drills to a specific and well defined field. We are constantly
in receipt of letters which show that there is a wide misappre-
hension of their capabilities. Hence these remarks.

WHAT CANNOT BE DONE WITH KEYSTONE DRILLS

1. Nothing but a perpendicular hole can be made.

2. Except with our form of percussion core drill, no core
can be recovered.

But aside from these two considerations the Keystone
machines are universal prospectors.

It should be remembered that there is no formation
through which our drills will not penetrate.

This is a broad, but fully warranted statement. It is
based upon our twenty -five years successful, world- wide
experience. It is certainly an advantage to the explorer to
know beforehand that he will not find anything that will
prevent his getting down. This is one very great advantage
that our drills have over core drills of the ordinary type, or
any of the lighter forms of cheap horse -power percussion
drills.



DRILLING FOR PLACER GOLD 133

Another very great advantage is that the cost per foot for
sinking test wells with our machines is less than by any other
method. As compared with core drilling, the cost per foot
will perhaps not exceed one third. In other words, three
separate six-inch holes can be made with our machine to the
same depth, for about the cost of one two-inch test hole
made with a revolving core drill. Where it is desired to
determine the dip of a certain stratum it is necessary, no
matter what kind of holes are drilled, to sink at several
points.

It should be remembered that the large hole has another
distinct advantage in that a greater quantity of material is
recovered. The area of a core from a 2^" core hole is only
about two square inches, while the cuttings from a six-inch
hole made by one of our drills, represents an area of about
19 square inches, or nearly ten times as great. By our proc-
ess only sufficient water is introduced to mix the cuttings,
ail of which water, under ordinary circumstances is again
recovered by the vacuum sand pump, together with all the
cuttings. The presence of a surplus of water is no hin-
drance. There is nothing about the tools easily broken and
the operation requires but ordinary skill. Elsewhere we
give adequate instructions for all ordinary work, showing
how it can be done with accuracy and reliability.

Any of the machines described in this catalog can be used
both for prospecting in rock formations and for placer
testing by simply modifying the drilling tools to suit require
ments. But it should be distinctly noted here that the
drilling bits or "chisels" which are best adapted to solid rock
drilling are not at all suited for use in alluvial prospecting.
The former are too blunt and thick and if used, will have the



134 DRILLING FOR PLACER GOLD

effect of packing the cuttings off into the sides of the bore-
hole beyond recovery. And, on the other hand, a drill bit
which is suitable for placer prospecting is useless for drilling
in hard rock. The blade of the drill bit used for allu vials
being thin, it will inevitably make a three-cornered or "flat"
hole in a hard formation. However, either style of drill
bit can be used on the same drilling machine without chang-
ing any other item of the equipment in the least.

But the two processes are quite different, and to make this
difference perfectly clear we shall describe both. We shall
deal first with the Placer Testing Machines and their
operation.



DIRECTIONS FOR THE OPERATION OF

KEYSTONE MACHINES AND USE OF

ACCOMPANYING APPLIANCES



By R. M. Downie



MOVING AND SETTING UP

When the moves are short and the ground not too rough
the mast is not taken down. The Traction Machines
move themselves almost anywhere without the assistance of
animals, but the Non-traction usually require horses or
oxen to move them, unless the moves are short. Short
moves and steep inclines, unaccessible with horses, can be
made by unreeling the drill cable (200 feet long), anchoring
it to a tree or post and pulling by steam with the hoisting
gear of the machine. All the machinery remains mounted
at all times and is moved in its entirety. In swamps and
quagmires it may be found necessary to place relays of cord-
wood or planks.

The machine should be set so that the sills will be level
and out of wind crosswise, but lengthwise they may be a
little higher in front than in rear without detriment. By
means of the wedges provided, level the front bolster until
the crown pulley at top of derrick is plumb with the center-
line of the m*Mn* Reference to the illustrations on
page 178 will show the appearance when set up and
how the cable is rigged for use. The hinged derrick is
raised to position by means of the long wooden braces.
The derrick should lean a few inches forward at the top.

135



136 DRILLING FOR PLACER GOLD

TO STRING THE DRIILLING TOOLS

For the purpose of ordinary placer testing 25 or 50 feet
depth, the string of tools will consist only of three pieces ;
viz.: the "Rope Socket", Fig. 100; the "Stem", Fig. 102
immediately below it, and the "Bit", Fig. 116 below the
stem.




Standard Keystone Rope Socket Fig. 100



The Jars (Fig. 101) need not be put on until the test well
is 25 or 50 feet deep, and under favorable conditions it may
not be needed at all. When used it is inserted between the
Rope Socket (Fig. 100) and the Stem (Fig. 102). The
joints on all of these tools are made of steel or the best
grade of refined iron and are what are known as "taper
joints." They are fully twice as strong as the old fashioned
"straight joint." The collars are 4J4 inches in diameter.
The "pin" (Fig. 108) and the "box" (Fig. 109) have squares
for the tool wrenches. When not in use the threads are pro-
tected from dirt and injury by "thread protectors." They
should be perfectly clean before putting together.

This tool is used to keep the bit from becoming fast in the
well. Not needed until 30 or 50 feet is reached, and often
not then.

The Rope Socket (Fig. 100) shows the drilling cable
already in place as it is when shipped.

To put the tools together, place the stem (Fig. 102) on the
ground with the pin end of it near where the well is to be,
and having drawn down a little slack cable, screw the rope



DRILLING FOR PLACER GOLD 137

socket on; also screw on the thin spudding-bit (Fig. 116)
and set the joints up temporarily with the tool wrenches
(Fig. 110) as tight as can be done by hand.

The Drill Stem is composed of a piece of round iron 4
inches thick and of a length and size to suit the machine.
To the upper end of it is welded a male screw, or "Pin",
Fig. 108. On the lower end is welded a female screw, or
"Box", Fig. 109.



Jars Fig. 101

This done, the engine is started and the entire tool is
drawn up until the lower end of it is about 3 feet from the
ground, and the brake applied to the cable reel to hold it
suspended.



Drill Stem Fig. 102

The Box and Pin are made in exact duplicates. There
are many sizes of them manufactured, but those used on the
machines shown in this catalog are known as "2 x 3 x 4
8 threads."

In subsequent operation, and when changing the bit for
dressing, etc., there is a sleight in putting it on the stem.
One man with the bit holder (Fig. 159), lifts the pin of the
bit into the box of the suspended stem and holds it there
while the attendant twists the stem until one or two threads



138 D RILLING FOR PLACER GOLD




Fig. 110 shows method of using the wrenches with floor circle



DRILLING FOR PLACER GOLD 139

are engaged. Then the bit is turned by hand until the
shoulders meet, the tool wrenches applied and the joints set
up firmly. Before a joint passes below the surface it should
be set up in a manner shown in the illustration below.

The wrenches should be put on the squares so as to pull
toward the hook side as shown in the illustration. The
upper one of the two in the illustration below is the "right-
hand" wrench, and the one on the floor is the "left-hand."
They are much stronger when thus used. The joints should
be put together with all the force two persons can exert on
the wrench bar. There is no danger of getting them too tight
or of breaking the j oint if made of the proper material . Never
hammer the joint, either to tighten or loosen it, as this
spoils the threads. About one-half of all fishing jobs arise
from not screwing up the joints properly, and about two-
thirds of the balance arise from using poor material in the
joints, causing them to break in the well. In this respect,
however, our customers have no trouble. Our joints are
made with the utmost care and with the best material
obtainable.





Pin Stub Fig. 108 Box-StubFig. 109

After a joint has been set up perfectly solid, a slight mark
may be made across the joint with a sharp cold chisel, half
of it on the pin collar, and half of it on the box. Each suc-
cessive time this joint is screwed up, the mark on the box
should go a little farther past the mark on the pin collar.
In this manner it may always be known when the joint is



140 DRILLING FOR PLACER GOLD




DRILLING FOR PLACER GOLD 141

set up firmly. If at the next setting up it does not go far
enough, you will know that there is dirt on the faces of the
joint, or in the threads which should be removed.

When bedrock is reached, and if it be desired to drill some
distance into it, or if a nest of heavy and hard boulders be
encountered, the "spudding bit", Fig. 116, is taken off, and
in its place is put on either a Mother Hubbard Bit, Fig. 104,
or else a fluted rock bit like Fig. 105.

Fig. 104 is used only where the rock is full of wide seams
and fissures, or where the strata may work out and cause the
joint to become loose in the well. One mark on the box
will be sufficient, each bit having one to match it. The
perforated iron shown on the floor is known as the Floor
Circle.




Fig. 110 Tool Wrenches like the above are used. The method of using the
Wrenches is shown in the illustration on page 138.

When making short moves it is not necessary to take the
drilling tools apart, the whole tool being carried upon
brackets provided for it on the side of the machine.

Being nearly as wide at the top as at the cutting point, and
the steel being very thick, the bit so nearly fills the hole that
it cannot slip off sidewise into slanting openings to make a
crooked hole.

Since there are only special localities where such a bit as
Fig. 104 is necessary, it is not furnished with machines unless



142 DRILLING FOR PLACER GOLD

specified in the order. It will not drill as rapidly as Fig. 105,
because the edges of the bit fit the hole more closely and
cause more friction. With the equipment of any machine
in this catalog it will be substituted for Fig. 105, without
change in price, when desired by the purchaser.

For drilling in rock, Fig. 105, the Fluted Rock Bit, is
generally used and is always furnished unless otherwise
specified. By a reference to the Equipment List on a suc-
ceeding page, it will be seen that there are three bits fur-
nished regularly with each placer testing outfit. Two of
these are Fig. 116, the Thin Blade Placer Bit, and one of
them is Fig. 105. The bits Fig. 116 are used in common for
sinking the test tube, but if a heavy bed of boulders is found,
or if it be desired to drill into a hard rock, Fig. 116 is taken
off and Fig. 105 substituted.

It is a mistake to use Fig. 105, however, in strata of gravel
and sand. This bit being designed originally for water and
oil well drilling, where speed is the prime requisite, was made
heavy and blunt. In a gravel or sand formation it will
inevitably pack the material in its pathway and drive a
considerable quantity of it off into the sides of the well, thus
to a certain degree destroying the accuracy of the test.
Fig. 116, is designed especially for placer prospecting, is
made thin in the blade like a carpenter's chisel and will
never pack the sand or gravel off into the sides of the bore
hole.

During the spudding operation with which the well is
begun the cross piece on the front of the walking beams,
which carries the temper screw when in use, is unbolted and
moved back a few inches. It may be entirely removed if
desired. If left in place it will interfere with the stem and



DRILLING FOR PLACER GOLD



143






KEYSTONE CUT DRIVE
PIPE

In Placer Gold Testing it is
desirable that the pipe, or test
tube be of the most substantial
quality; that it be cut in short
lengths for ease in handling;
and that the couplings and pipe
be so threaded that the ends of
the tubes will butt in the middle
of the couplings so that there
may be no danger of stripping
the threads, in heavy driving.

For this purpose we use only
the best grade of Extra Heavy
Drive Pipe. The cutting and
threading are done under careful
supervision in our own factory.
Drive Shoes, driving heads, etc.,
are forged and machined by us
and threaded to accurately fit
the pipe. Since it is of the ut-
most importance that all joints
be perfectly matched and inter-
changeable we suggest that pipe
to be used with our prospecting
drills be purchased through us,
particularly if it forms part of
equipment to be shipped abroad
or into distant and inaccessible
places where replacement would
be slow and difficult.

The cut herewith shows a test
hole, including drill stem, drive
clamps, drive head, couplings, a
short length of pipe, drive shoe
and placer bit.







144



DRILLING FOR PLACER GOLD



DRILLING FOR PLACER GOLD 145

cable and be battered to pieces. On our larger machines
will be found a special device for shifting this cross piece
into and out of place.

To start the well, proceed as follows: Swing the drilling
tools, now consisting of bit, stem and rope socket, in the
derrick and set the reel brake in such a way that the point
of the drill bit will not quite touch the ground when the
walking beams are at their highest limit and the drilling
tools are accordingly at the lowest limit of their stroke.
The engine and the countershaft driven by it will now be out
of gear with all the other machinery. While the engine is
at rest throw the geared crank wheel into mesh and see that
the latch holds it there securely. Now start the engine
slowly, and after the weight of the drilling tool has taken up
the slack cable, with the brake lever let the drilling tool down
until it will barely touch the ground at the limit of its down-
ward stroke. This will mark the spot where the well is to
be made. Until the operator has learned to "balance" and
steady the drilling tool from the surface, the attendant may
temporarily take a position behind and on one of the cross-
pieces of the derrick and steady the top of the drilling tool
until a start has been made. Now start the engine, slowly
at first, until the operator "gets the swing of the tool", and
slacken the brake a little to let the cable run off far enough to
allow the drill bit to touch the ground. A few blows will
suffice to make an impression and start the hole. A little
water should be supplied as needed, and as the hole deepens
allow the cable, an inch or two at a time, to run off the reel.
The operator, standing beside the well during this time, will
steady the drilling tool, confining the blows to a central
point and turning the tool a little at each blow so as to make



146



DRILLING FOR PLACER GOLD




DRILLING FOR PLACER GOLD 147

a round hole. But in case the material at the surface is
composed of loose sand or gravel, it may be found advisable
to excavate with a shovel a hole about two or three feet deep
and in this plant a 4 or 6-foot section of the drive pipe, with
the drive shoe screwed firmly on the lower end and a sleeve
coupling on the upper end. Drive first where possible, as
it usually is. Sand and gravel may be tamped in about this
section of drive pipe to hold it plumb, and in such case the
drilling tool must be drawn up and entered over the top of
the drive pipe. Proceed 2, 3, 4 or 5 feet, or until the cuttings
become too thick to allow the drill to drop freely; then
throw the crank wheel out of gear and the cable reel into
gear and draw the drilling tool up until the bit is 2 or 3 feet
above ground, and hold it there with the brake. When the
Friction-geared Machines are used this can be done without
stopping the engine, but when the Cog-geared Machines are
used the engine must be stopped before throwing the cable
reel into gear. Swing the bit out of the way, holding it
with a loop or cord while the sand-pumping is done.

The common sand pump, Fig. 160, may be used to clear
the hole of the cuttings. But if the soil be marsh or sand,
having a tendency to cave in, the drive pipe should be
driven down as far as the drill has penetrated.

The cuttings in the form of mud or mortar, enter the
pump at the lower end and a valve prevents them from
flowing out when the pump is raised. If the mud in the well
be so thick that the sand pump will not readily sink through
it to the bottom, raise the pump a foot or two and let it fall
repeatedly until it is filled with the cuttings. It is then
drawn up and emptied and the process repeated two or
three times, or until the drill hole is entirely cleared of



148 DRILLING FOR PLACER GOLD

cuttings. A pail or two of water is then put into the drill
hole, the drilling tool again lowered and the process re-
peated.

With each outfit there is furnished, in addition to the
regular sand pump, Fig. 161, our Vacuum Sand Pump. The
latter is made in two styles, with side dump, Fig. 161 and,
with drop bottom, Fig. 230. These two styles of the
vacuum sand pump are used for the same purpose and pur-
chasers may take their choice at about the same price. The
difference between them is that Fig. 161 must be turned
bottom up in order to empty it, while Fig. 230 is unloaded
by tripping the latch which supports the hinged bottom.
Fig. 230 has the larger opening through the valve and will
therefore admit larger gravel; and owing to the fact that
the whole bottom drops out of the way, it will handle coarse,
chunky and sticky material more easily. But, on account
of its form, it must be used with more care than Fig. 161.
When being lowered against a solid rock or boulder forma-
tion it should be let down gently and not dropped recklessly.
The suckers of both pumps are packed with leather or
rubber discs held in place by washers and lock nuts. This
packing must eventually be replaced by the operator.

The Vacuum Sand Pump contains a valve or "sucker",
which travels the whole length of the pump. When the
pump is lowered into the well, this "sucker" goes to the
bottom of the pump, being forced down by a heavy iron
sucker-rod within it. When the sand reel is thrown in gear
this sucker is drawn up rapidly and produces a vacuum in
the lower part of the pump. The sand, clay, water and
small stones are drawn into the pump by the inrush until
it is full to the top.



DRILLING FOR PLACER GOLD 149

When the sucker is lifted, the vacuum formed, and the
contents of the well drawn in, the pump (per force of the
vacuum formed) sinks and it will often bury itself two or
three feet in the formation at the bottom of the well pro-
vided the material is not too solid.

The great advantage of the vacuum pump over the com-
mon one is at once manifest. It will pull into itself any-
thing and everything small enough and loose enough to be
taken. If gold or other minerals are present they are swept
in with the current of mud and slush. The common sand
pump will not do this, but will simply take out what will,
by gravity, flow up through the valve. The operator must
determine which pump is to be used at the surface where
the principal object usually is to simply clear the hole.
But when a point is reached at which minerals are expected
the vacuum sand pump should always be used.

The efficiency of the vacuum sand pump depends upon
being lifted quickly. To this end the sand reel is operated
by a powerful and rapid friction gear. The sand line should
be securely attached, and in such a way that it will not cut
where it is fastened to the sand pump. It is not uncommon
that a lift of 2,000 pounds or more is required to start this
pump if it has pulled itself 2 or 3 feet into the sand and gravel.

When testing for lead, zinc and iron ore, or in fact any
mineral, this vacuum sand pump will fetch up everything
in the hole. Its efficiency may be tested by throwing a
handful of bird-shot into the well and sending the sand
pump after it.

Where the well is to be started in a river bed or lake
bottom, in a swamp where the water comes to the surface or
in sandy soil which will not stand up at all without being



150 DRILLING FOR PLACER GOLD

cased, it will be necessary to drive the pipe from the very
first. It is always advisable to do this.

THE DRIVE PIPE

The Placer Testing Machine, being generally used where
there are boulders, sunken logs and debris, is equipped for
using six-inch (inside diameter) drive pipe for hard driving.
This drive pipe, unlike the ordinary Merchant Pipe, is
made with straight threads, and the ends, being cut square
off, meet in the center of the coupling. See Fig. 203.

For convenience in handling, this pipe is made in lengths
of from 5 to 7 feet.

Since the amount required varies with different localities,
this drive pipe is not included in the price of the machine,
but is furnished by us as an extra in amounts and lengths
to suit.

In Placer Testing this drive pipe must in all cases be
driven to bedrock so as to insure that an exact area of test
hole be carried clear to the bottom. Hence it is absolutely
necessary that there be sufficient pipe at hand to reach the
entire depth of the alluvial exploration. It cannot be driven
into the solid rock, nor does it require to be further driven
after bedrock is reached. But, while the depth of the allu-
vial deposit will determine the amount of pipe absolutely
required, it is a common practice with our customers to
order from two to three times this amount, so as to have
a supply from which to replace injured sections. The joints,
couplings and drive shoes are all made interchangeable and
additional sections can be ordered from us at any time.
After a test is completed the drive pipe is withdrawn; it
may be used over and over again.



DRILLING FOR PLACER GOLD



151



There are two weights of drive pipe alike in quality, but
differing in strength, weight and thickness. The lighter
weight is about % inch thick, and is sufficiently heavy for
all ordinary purposes. The "X Heavy" is about Yi inch
thick, and is furnished for the most difficult work, where
there are many boulders, or when great depths must be
driven. The outside diameter of both the light and the
"X Heavy" is the same, and the same sleeve couplings and
drive shoes will fit both weights. Owing to its thicker walls,
the actual inside diameter of the "X Heavy" grade is only
about 5 Y% inches. Also the same size of drilling tools and
bits are used with both weights the bits being dressed by
the operator to suit. Purchasers may therefore take any
proportion desired of either weight.




Drive Pipe Coupling

When the test is to be made from a boat in a lake or river
bed, enough of the drive pipe is screwed together to reach



152



DRILLING FOR PLACER GOLD




DRILLING FOR PLACER GOLD 153

the bottom of the water and extend up 2 to 6 feet above the
floor of the boat. When the test is made in ground which
must be cased from the surface, one short section (say 7 feet
long) is set up at the point where the well is to be made, with
the drilling tool inside of it.

EXPLORING FROM A FLOAT OR FLAT BOAT

The machines described in the catalog being self-con-
tained, are admirably adapted for use on- flat boats for ex-
ploring lake beds, river channels or water covered marshes.

We do not cumber this catalog with detail plans for con-
struction of the boat, but we will, without charge to pur-
chasers of machines, furnish full plans and specifications.
The lumber for boat construction can usually be had more
cheaply at the place where the work is to be done thus
saving transportation charges. However, we will upon re-
quest quote prices upon the materials all cut to size, to be
loaded upon same car with machine. The weight of the
materials for a 40-foot boat 15 inches deep is about 8,000
pounds, and will with a machine and outfit of pipe make
something over a minimum car load.

In use the boat is securely anchored with lines or spars
over the spot to be prospected and through a conductor
raised level with the top of the boat, the drive pipe is let
down to the bottom. The depth of the water is immaterial
except that the deeper the water the more pipe will be re-
quired. When the pipe has been set on the bottom the proc-
ess is precisely similar to that described for prospecting on land .

When the test has been made the drive pipe is withdrawn
by means of the Pipe Jars (included with regular Placer
Testing Outfit) and the boat floated to next location.



154 DRILLING FOR PLACER GOLD

The tests made in this way have been proved absolutely
reliable and some very rich deposits have been found. The
pipe pulling apparatus and the means of operating it make
these machines peculiarly adaptable for this class of work.

To protect the lower end of the drive pipe from injury by
being driven against boulders or slanting ledges, or being
injured by the sharp corners of the drilling bit, and as well
to insure that an exact area or section be excavated, a
wrought steel Drive Shoe, Fig. 175, is used. It is usually
made 7^ inches in diameter at the cutting edge, and this
represents the area excavated.




Fig 175 Wrought Steel Drive Shoe

It is slightly beveled inward and has a tempered edge.
It is threaded to receive the 6-inch drive pipe, and has a
shoulder against which the end of the pipe rests, as shown by
the cut-away section in Fig. 175.

It is of prime importance that the drive shoe be firmly
screwed on the pipe. It is made large enough to allow the
pipe couplings to follow. In testing placer ground for gold,
it is also of prime importance that this shoe have a perfect
edge so as to cut an exact area, and that the pipe be driven
so that at no time will the drill bit project any considerable



DRILLING FOR PLACER GOLD 155

distance below it. Otherwise, especially if the formation
be of a caving nature, more than the area of the shoe will be
excavated and an exactness of assay may not be obtained.
For this reason the operator should have several of these
drive shoes with his -outfit, say three to five.

DRIVING THE PIPE

Whether the pipe is to be driven from a boat or started
from the surface, as in a swamp, or whether, as in dry clay
ground, a few feet has been first drilled, the drive pipe with
the shoe in place is set as above described, plumbed and




Fig. 15712 Driving Clamps

drilling is proceeded with. For a time the pipe may go
down without driving, and were it not that the accurate test
is desired the pipe could be let down quite a distance by
drilling ahead of it. But if it does cave in so that the
volume of material taken out with the vacuum sand pump
is greater than the contents of the hole as represented by
the cutting edge of the drive shoe, the accuracy of the test
at that level will be spoiled. Therefore it is better to drive
the pipe ahead wherever the material is soft. But it should
also be remembered that it is possible to drive the pipe too



156 DRILLING FOR PLACER GOLD




DRILLING FOR PLACER GOLD 157

far ahead of the drill. If driven too far the materials may
pack in the end of the test tube instead of rising into it. In
such a case part of the material which should be taken out
is driven off into the sides of the hole and not recovered,
interfering with the accuracy of the assay.

In that part of the distance to be sunk in which no gold
is found, it is immaterial whether the pipe is driven ahead
of the bit or not, so it is gotten down. As a matter of fact it
goes down more quickly and easily when the drill is kept well
ahead, when the only object is to get the pipe down. Opera-
tors will therefore, have to use their discretion and be
governed by circumstance. In any case the Driving
Clamps, (Fig. 157^) are put on the stem as shown in the
accompanying illustration. The illustration also shows the
Driving Cap in place on the coupling.




Fig. 340 Drive Clamp Wrench



The Driving Clamps (Fig. 157H) are, for common, put
on the square at the upper end of the drill stem, the bolts
being firmly tightened. But this square on the upper end
of the stem being about 13 feet from the point of the bit,
unless the hole is at least 13 feet deep (measuring from the
top of the pipe), it may not be possible to use the driving
clamps on the upper square of the drill stem. In such case
attach them to the stem at the place prepared for them at
mid-length of the stem until they can be used at the top.



158 DRILLING FOR PLACER GOLD

In placer prospecting the Keystone Special Drive Head
(Fig. 173) is used to best advantage. It is the simplest
form of drive head obtainable, being made of a coupling and
a nipple of extra heavy drive pipe. The cut entitled
' 'Prospecting Crew in the Field", shows this drive head
in place.




Keystone Special Drive Head

The pipe is driven by the weight of the drilling tool, by
striking the driving cap with the driving clamps. The
stroke of the drill (about 30 to 36 inches) will represent the
length of the blow and the weight of the entire drilling tool
(about 800 Ibs.) will be the heft of the hammer. If the pipe
drives hard place a matting of old rope, or any such sub-
stance, on top of the iron driving cap to cushion the blow.
After driving 1, 2, 3 or 4 feet, according to circumstances,
remove the driving clamps by taking out the bolts. Let the
drill to the bottom and cut up the material in the pipe,
adding water if need be.

Then use the sand pump as before directed. All material
taken from the test tube should be carefully saved and
panned.



DRILLING FOR PLACER GOLD 159

A record of the length of each piece of pipe driven should
be kept in order that it may be known exactly how deep the
test tube is at any point of the proceeding, otherwise it may
be difficult at times to determine whether the drill bit is
working in the pipe or ahead of it.

The drilling bits should be dressed to the neat size of the
bore of the pipe and the cutting edges should be kept as
nearly as possible in the form in which they are when sent
from the factory.

When putting the drive pipe together, clean the threads
with a brush and lubricate them with a mixture of graphite
(stove polish) and linseed oil. In no case allow any oil or
grease to get inside the drive pipe, as it is liable to work down
and be mixed with the materials cut up preventing the
possibility of panning out the gold. The accuracy of the
test may be badly spoiled by allowing oil or grease to get
into the hole.




DRESSING THE DRILLING BITS

The instructions given herewith are general and cover
both rock drilling and placer testing.



160 DRILLING FOR PLACER GOLD

The correct form for the bits will be learned from these
cuts. Also the bits are correctly dressed when sent out, and
their form should be particularly noted, and one may be
kept for a model until the operator can duplicate it.

This cut (Fig. 154) illustrates a bit dressed for drilling a
round hole in hard rock, and shows how the corners should
fill out the gauge. The distance from A to F should be the
same as from C to D or B to E.

To dress the bit attach one end of blast hose to the spout
of the fan. The other end has on it a piece of two-inch pipe.
Thrust the pipe firmly into the "tuyere iron." Within
reach of the blast hose make a pit in the ground about the
depth and size of a large wash basin, and place the tuyere
iron in it. For heating the heavy bits this arrangement is
better, lighter, cheaper and handier than an elevated forge.




Use soft coal for fire, if you can get it, but hard coal or
even charcoal may be used for a bit dressing. Heat the bit
to a cherry red for a distance of three or four inches back
from the point, turning it occasionally in the fire to get
both corners alike hot.



DRILLING FOR PLACER GOLD



CAUTION



161



Drillers often make a mistake in not heating the bit far
enough back. If a bit is heated at the point only, the ham-
mering of it spreads the surface, but not the center.

By use of the "spectacles", Fig. 159, drag it upon the
anvil block, and with the sledge spread it to a size somewhat
larger than the bit gauge. Begin striking in the center and
follow out to each corner. Turn the bit over and hammer
the other side in the same way.




The "Spectacles" or Bit Holder

The next cut illustrates an improperly dressed bin for
hard rock, but it is just right for placer testing work. It
hard rock such a bit is likely to drill a three-cornered hole.




Fig. 158 Anvil Block

Turn bit on its edge with the lower corner projecting a
little over the anvil billet, and make the corners ABC and
D E F cutting edges. The corners of the bit do nearly all
the cutting. The bits should conform to the circle of the
gauge at the edges when the gauge is put on it at one-half



162 DRILLING FOR PLACER GOLD




Tempering Bit



DRILLING FOR PLACER GOLD 163

inch from the point. See Fig. 154. Keep the channels of
the flute (see Figs. 103, 104 and 105) clear by using a cold
chisel if in dressing, the steel laps back into the channel.
Keep the bit straight across the face or cutting edge from
B toE.

In smithing the Placer Bit, Fig. 116, the tool dresser
should avoid making a blunt, cutting end like that used on
Fig. 105 in hard rock drilling. This bit should be dressed
with a sharper and thinner cutting edge, more like that
shown in the illustration, Fig. 304.

To temper a drill bit, heat evenly to a very dark cherry
red in the sunlight, and to a lighter cherry red in the shade
or on a cloudy day or at night, but never heat steel until it
throws off sparks. The sparks indicate that the carbon is
being burned out of the steel, and it is thereby destroyed.
See that the entire face of the bit is of even heat for about
two inches back from the cutting edge, then set the bit
plumb in not over one and a half or one and three-quarters
inches of water. See Fig. 159.

With a stick, keep the water circulating for a minute until
the point of the bit is cooled off. Tilt the point of the bit
out of the water, and after rubbing the hammered part with
a piece of stone or brick, to remove the scale, you will see a
succession of colors creep gradually toward the point of the
bit, as the heat runs down toward the end. The foremost
one may be nearly white, the next "straw color" or orange,
the next a deep yellowish * 'purple", then "blue", and finally
black. The "white" is too hard for any kind of rock except
soft slate, etc. The "straw" or orange is likewise too hard
for hard rock, and will cause the edge and corners of the
bit to crumble. The deep "purple" or "blue" is about right



164 DRILLING FOR PLACER GOLD

for the hardest rock, and is the temper used for mill picks,
etc. The "black", of course is too soft, and a bit tempered
to that color will soon lose its cutting edge and batter like a
piece of iron. So soon as the purple or blue runs down to
within three-fourths or one-half inch of the cutting edge,
tilt the bit back into the water, stand plumb, and let it cool
off. After the operator has tempered these drills a few
times he will learn to gauge by sight the proper heat to pro-
duce the proper temper, and after this he will not need to
take the bit out of the tempering tub to watch the colors.

The tool dresser should see that the threaded end of the
bit is entirely cold before it is put on for drilling, otherwise
the screw may shrink and loosen the joint after the tools are
lowered into the well. Remember that,

One-half of the art of drilling is in knowing how to dress
the bit properly.

The reason for not tempering in deeper water is that the
heavy body of steel will not quickly cool to the center. The
outside shell will cool, contract and it may even crack open.
The cracks thus formed become deeper at each heating and
cooling, until pieces may spall off. The better the steel and
the higher the carbon, the more likely is this to occur, but it
can easily be avoided by tempering in shallow water as
directed above, and only tempering the part which has been
hammered. Always dress the bit out to the full gauge of the
hole you are making.

The Clay Socket (Fig. 198) is used to take up soft ma-
terials intact. It is useless where boulders exist or in hard
materials. But it frequently happens that overlying the
bedrock where gold is found there is a plastic silt, clay or
volcanic ash. In such places this tool is very satisfactory.



DRILLING FOR PLACER GOLD 165

It works inside the 6-inch drive pipe, and is operated by
being screwed on the drilling stem instead of the usual
drilling bit.

PULLING THE PIPE

When a test well has been finished, the drive pipe used
should (for economy) be drawn to be used over and over
again till worn out. This is done by means of a pair of
Keystone Pipe Pulling Jars, Fig. 500.

This tool is used for raising out of the ground the pipe
which has been driven. It can be used in combination with
the pulling ring and lifting jacks described on a following page,
or it can be used alone. In use, the drill bit and stem are taken
off and the Pipe Jar screwed on in place. The threaded
knocking head (Fig. 501) is screwed into the coupling on the
upper end of the pipe to be drawn. The machine is then
set in motion and the tool drawn up so that the ram will
strike against the lower side of the knocking head.

Our Special Pipe Clamp, Fig. 174, is then fitted on the
pipe below the first collar and is used to keep the pipe from
sinking back as it is raised by the Pipe Jar.

The Placer Testing Machines are friction geared so that
the cable can be taken up as the pipe rises, without stopping.
The weight of the tool serves as a hammer and the jarring
will easily start a line of pipe which may be too firmly held
to be drawn with the pulling ring and jacks alone. As the
pipe rises the operator simply takes up the slack of the drill-
cable until a full length of pipe is above ground. When the
pipe is not too firmly held, this tool will raise it without the
assistance of the jacks and do it very rapidly. The pin of
the pipe pulling jars is threaded to fit the rope socket, and



166 DRILLING FOR PLACER GOLD










DRILLING FOR PLACER GOLD 167

the knocking head is threaded (unless otherwise ordered) to
fit the coupling of six-inch drive pipe.

It will be noticed that the knocking head (Fig. 501) has a
square opening. Into this the squared shank of the tool
drops and one of the drilling tool wrenches, (Fig. 110) is then
used to screw or unscrew the threaded knocking head from
the drive pipe. The knocking heads are hardened against
battering and the whole tool is durable and handy.

A special necessity for the tool is found when pipe has to
be driven and pulled from a float or boat when exploring
river or lake beds, or testing under deep water for bridge
piers, etc. In such cases the power required to pull the pipe
by jacks is usually too great for the buoyancy of a boat or
float, while with the pipe jars the pipe is raised by blows.
Pipe that has been driven fifty feet into river silt and sand
has been raised from a light flatboat without the use of
jacks. It will be made to fit any desired size of pipe, and
can be made so the same knocking head will fit two or more
sizes of pipe, if so ordered.

PIPE PULLING RING




Fig. 190



There is also included with the Placer Testing equipment
the Pipe Pulling Ring and Wedges (Fig. 190), and a pair of
jack screws with which to operate it. The ring is made of



168



DRILLING FOR PLACER GOLD



Keystone
Pipe Pulling
Jar




Fig. 501.
Knocking Head



Fig. 500.



DRILLING FOR PLACER GOLD 169

cast steel with wrought steel, tempered, gripping wedges,
which will catch the pipe at any point. It is used princi-
pally to start the pipe from its bed, if need be, after which
the pipe pulling jars will draw the pipe in a fiftieth part of
the time the screws could be operated.

The use of the various other appliances found in the
Equipment List will be understood without explanation.



170 DRILLING FOR PLACER GOLD




1 I
II





THE SCIENCE OF ZINC AND LEAD

PROSPECTING WITH THE CHURN

DRILL

By R. M. Downie

General Manager of Keystone Driller Company

Drilling a hole into the ground is not necessarily prospect-
ing. Indeed, it is possible to drill a six-inch hole right
through a ledge containing lead and zinc without at all
detecting their presence. This was fully demonstrated some
years ago in the Joplin District. Indeed, there was a time in
that field when land owners would no longer lease their
ground if it was to be prospected with a drill, for it had been
fully proved by shafts afterward sunk, that much ground
that had been condemned by improper drilling, actually
contained paying quantities of mineral.

It has now been proved that the cheapest and best
method of prospecting for these minerals is by means of
the "Churn Drill", provided the proper kind of appli-
ances are used. The only other methods are: First
By digging shafts ; and, Second By means of the "core"
or "diamond" drills. The sinking of a shaft is a slow and
expensive process and involves the disfigurement of the sur-
face so as to permanently injure the ground for agricultural
purposes. Theoretically, the "core drill" would be the ideal
prospector; but, unfortunately its cost is too great, its
operation too expensive, (three or four times that of the
churn drill), and, finally, it is practically inoperative in the
sort of broken and conglomerate formations in which zinc
and lead are found in paying quantities. Prospectors are

171



172 DRILLING FOR PLACER GOLD

therefore practically confined to the use of the churn drill.
When scientifically constructed, and intelligently handled,
it serves the purpose admirably, doing the work cheaply,
rapidly and reliably.

As we have noted at the outset it is possible with a churn
drill to sink a hole through a vein of lead or zinc, and,
through ignorance or lack of proper appliances, fail abso-
lutely to detect its presence. It is possible also to drill
through a mineralized stratum and obtain only a small or
uncertain percentage of the minerals, thus making a decep-
tive and unreliable test, and, perhaps, appraising as next to
worthless, ground that may be very rich. Unless all the
mineral lying in the path of the drill and within the area
excavated by it is brought to the surface, the test is next to
valueless. If as little as ten per cent of the ore is lost, it
may make all the difference between a profitable and an
unprofitable prospect. Or, exasperating and tantalizing
doubts may remain to tempt further expense or loss in shaft
sinking.

Again, it is possible to drill a mineralized stratum of small
or medium thickness in such a way as to make it appear two
or three times as thick as it really is. Mistakes of this kind
can be made by honest ignorance, and thousands of them
have occurred in the Joplin Field, causing the loss of much
money in sinking non-paying shafts and in running expen-
sive drifts after mere streaks.



TWO PRIME REQUISITES IN A
PROSPECTING DRILL

A Long Quick Stroke. A Vacuum Sludge Pump

QUICK STROKE HOW OBTAINED

The first necessity in a prospecting drill is a long, quick
stroke the quicker the better. All of the percussion drills
in use, including the Keystone, operate the drilling tool by
gravity; that is, they raise the drilling tool on a cable by
various sorts of crank, lever, trip or treadle mechanisms and
let it fall of its own weight. This being true, the only thing
that can be done to accelerate the down-stroke is to drop the
tool with a perfectly slack cable, which the Keystone does
in a manner peculiar to itself. This maximum speed of
down-stroke being secured, it is equally important that the
machine have a quick and powerful up -stroke, and in this
respect the general speed of the stroke can be increased
rather more indefinitely, depending upon the power and
promptness of the operating mechanism. The Keystone is
so constructed as to lift the tools in one -third of a revolution
of the drive wheel. During the remaining two-thirds of a
revolution the engine precedes the falling drilling tool.
Thus, about 60 thirty-six inch strokes can be delivered per
minute.

TENDENCY OF DRILLINGS TO SETTLE ON BOTTOM

Lead is about eleven times as heavy as water and pure
zinc is about seven times as heavy as water. Compared
with sand or clay, bulk for bulk, lead ore is about five times
as heavy as wet sand, clay or cut-up rock, and zinc ore

173



174 DRILLING FOR PLACER GOLD

("Jack") is about three to four times as heavy as the cut-
tings of the rock in which it is found. If, therefore, lead or
zinc ores are broken, as is always more or less the case when
cut up by a drill and mixed with sand, clay or cut -up rock
and water, and allowed to settle, the lead and zinc will
always be found at the very bottom of the vessel. This is
exactly what happens in the bore hole when these minerals
are struck with the drill unless prevented by the action of
the drill itself.

TRITURATION OF DRILLINGS BY
SLOW MOTION DRILLS

In the process of drilling, enough water must always be
supplied to make a sort of batter or "sludge" ; but generally
it happens that water is found in the drill hole, above or
in connection with the mineral largely in excess of what is
actually needed, so that the cuttings are thoroughly
saturated and washed, and if given any chance to do so, the
mineral cuttings will immediately and during the process of
drilling seek to settle upon the bottom of the drill hole as
noted above. So heavy are they that, with a slow motion
drill (30 to 40 strokes per minute), the cuttings will even
settle between each two strokes of the drill and the descend-
ing drill-bit will, in that case, cut, recut and pulverize the
chips so finely that most if not all are likely to be lost.

HOW TO PREVENT DRILLINGS FROM
SETTLING ON THE BOTTOM

The stroke of the drill must therefore be long enough and
quick enough to prevent this settling. Practice shows that
the length of the stroke should be 36 to 40 inches and the
drill should deliver 60 to 65 such strokes per minute.



DRILLING FOR PLACER GOLD ITS

Most of the "well drills" now in use in the lead and zinc
field, however, have a stroke of only 12 to 15 inches, and
even with this short stroke the drill strikes only 35 or 40
times a minute and the plan of the machines makes it utterly
impossible to obtain the proper long, quick stroke.

KEYSTONE DRILL-TRAVEL 360 FEET PER MINUTE

The Keystone strikes 60 three-foot strokes a minute.
This means a total drill-fall, per minute, of 180 feet; a total
drill travel of 360 feet. It means that the drill is lifted in
one -half the time it takes it to fall with a slack cable. (A
full explanation of how this quick and powerful up-stroke is
obtained can be found in our No. 1 Catalog.) On the
other hand, some well drills being used, taken at their
best speed, will not give a drill travel of more than one-half
or three -fifths that of the Keystone. In this respect it
stands alone, lifting the drill during about one-third of its
crank motion and then allowing it to descend with a per-
fectly slack cable during the remaining two-thirds of its
crank movement. This accounts for its quick action.

A SIMPLE EXPERIMENT

If our statements that a reliable test cannot be made with
slow-stroke drills be questioned, try the following simple
experiment: Take a weighed pound of lead or zinc to a
well where one of these ordinary outfits is in use. After
the hole is cleaned out, throw in the ore. After a distance of
two or three feet has been drilled in rock of average hard-
ness, let the well be sludged out. You will probably be sur-
prised to find that you will not be able to recover one ounce
out of the 16 you put in.



176 DRILLING FOR PLACER GOLD

The reason for this is that the comparatively slow and
short stroke of the drill allows the metal to settle between
strokes to be cut and recut at each blow of the drill until re-
duced to a powder so fine that it will float imperceptibly in
the sludge. And, if the pound of ore used in the experiment
had been encountered in the path of the drill instead of being
purposely put in, the presence of fifteen out of sixteen would
never have been revealed.

ANOTHER SIMPLE TEST

Count out 100 grains of bird or duck-shot and cast them
into such a prospect hole. After the drill has been operated
for a short time, say ten minutes, see how many grains of
shot can be recovered. If you recover a single grain that
has not been cut and flattened out, or if you recover one in
ten grains in any shape at all, you will be lucky.

Try the same experiment with a Keystone.

When the drill-bit leaves the bottom with its long, quick
up-stroke, it creates a displacement something after the
manner of a pump plunger. Its rapid withdrawal causes a
down rush of sludge, which picks up and carries afloat all
the cuttings, thus preventing them from being pounded up
on the bottom.

AN INCIDENTAL ADVANTAGE OF THIS QUICK STROKE

Incidentally, this also adds greatly to the speed of drilling
and is in a great measure responsible for the fame of the
"Keystone Gait", for whether there be mineral or not, the
bottom of the bore hole is kept clear so that the drill-bit will
strike the clear rock at each blow. It therefore costs less
per foot to make the test wells rapidly and reliably than



DRILLING FOR PLACER GOLD 177



to make them slowly and unreliably. As speed, however,
is a secondary consideration in the drilling of test holes,
we do not dwell longer upon this point.

THE SUCTION SLUDGE BUCKET

The Second Prime Requisite in Accurate
Test Drilling

The second necessity in a reliable prospecting outfit is a
means of thoroughly cleaning the bore hole after each run of
the drill -bit. No argument need be brought in support of
this statement. If any part of the mineral among the cut-
tings be left in the bore hole the test will be vitiated by so
much. The two simple tests we suggested above, if applied,
will convince any one that it is absolutely impossible to
thoroughly clear a bore hole of lead or zinc cuttings by means
of the common sludge buckets.

STILL ANOTHER TEST

If there still remains a doubt about this sweeping state-
ment, try this: Take a six-inch post hole auger and bore a
hole three feet deep in a clay formation that will hold water.
Into this hole put a mixture of clay, sand and mineral cut-
tings and mix them with water to the consistency of drilling
sludge. Now take a common sludge bucket and operating
it by means of a rope as is done in drilling, see if you can
recover with it all the mineral cuttings put in. One such
test will fully convince you.

FALSE ASSAYS CAUSED BY IMPERFECTLY
CLEANING OUT THE HOLE

To leave any part of mineral in the bore hole not only
robs the ground of part of its value, but these unrecovered



178 DRILLING FOR PLACER GOLD



V X




Drilling for Zinc



DRILLING FOR PLACER GOLD 179

cuttings will mix with those of the next bit run and will
inevitably lead to the conclusion that the mineral bearing
ledge is thicker than it really is.

All this difficulty is set aside by using the Keystone
Vacuum Sludge Pump. The principle of its operation, as
distinguished from the common sludge bucket is that a
vacuum is formed under its plunger, which creates a sharp
suction through its bottom valve. The downrush of sludge
on the outside of the pump, and simultaneously on all sides
of it, strikes on the bottom of the bore hole, licks up every-
thing loose and carries it up into the pump. It will pick up
lead shot from the smooth bottom of a bore hole, and this
should be a conclusive test that it will take up lead and zinc
ore.

The operation of this pump, it is true, requires good cord-
age, and a quick action reel; but, given these, it can be
operated upon any sort of machine.

KEYSTONE VACUUM SAND OR SLUDGE PUMP

EXAMINATION OF THE SLUDGE

Third Next in importance to having the right machine
and sludge pump, in order to make a test that is accurate
and reliable, it is necessary to save all the sludge taken from
the mineral producing strata. The reason for this we shall
now try to make clear.

Of course, under the sharp blows of the long-stroke drill,
the cuttings will be much coarser than those made by the
short, and therefore lighter, strokes of the common well-
drill, and, while the quick action of the drill which we have
just described will keep the drillings afloat and largely pre-



180 DRILLING FOR PLACER GOLD




DRILLING FOR PLACER GOLD 181

vent their pulverization, yet, under even the most favorable
conditions, some part of the ore will be powdered in the proc-
ess of drilling. The lighter the stroke and the slower the
motion the more the drill-bit will operate like the pestle of a
mortar. And here it should be remembered that nearly all
lead and zinc ores are crystalline in structure and very easily
powdered, and that it is easily possible to reduce these ores
to a powder so fine that a half pound of it will float almost
invisibly in a pail of clear water. The sludge taken from the
bore hole being in the nature of very muddy water or thin
batter, it is inevitable that a greater or less percentage of the
ore will be held afloat in it, and the thicker the sludge, the
longer it will require for the powdered minerals to settle.
It is the common practice of driller men to discharge the
thin and lighter portion of this sludge upon the ground, sav-
ing only the heavier settlings under the impression perhaps
that these coarser cuttings contain all the minerals. This is
a gross mistake, and a practice which, for the general good of
the mining business, cannot be abandoned too soon.

Perhaps the most convenient method of treating the
sludge is to discharge it into a prepared sluice box, say 12
inches wide, 10 inches deep and 8 feet long, made of sur-
faced inch boards with a cross partition 6 inches high, about
4 feet from one end, and another partition about 4 inches
high, 6J/2 feet from the same end. It will thus have three
compartments. Into the larger of these the sludge is dis-
charged from the vacuum sand pump. The heavier set-
tlings will remain in this apartment, but the thinner sludge
will overflow the 6-inch partition into the next compartment,
in turn, after dropping their lighter cuttings, will overflow
into the last and smallest. In the discharge end of the box,



182 DRILLING FOR PLACER GOLD

there may be a series of auger holes for slowly draining off
the muddy water. The partitions may be set in loosely
between strips so as to be easily removable for final clean-
ing up. After allowing reasonable time for settling the top
water should be drawn off and more water (easily supplied
from the well) should be added to carry away the earthy
matter. For preliminary examination the coarse settlings
collected in the larger bin may be scooped up and washed
returning all the wash water to the sluice box, and after-
ward the entire contents of the sluice box can be handjigged,
panned or assayed.

(End of Part Two)



DRILLING COSTS IN POTASH PROSPECTING

By E. E. Free*

During the summers of 1912, 1913 and 1914 the Railroad
Valley Company of Tonopah, Nevada, carried out an exten-
sive prospecting campaign for potash deposits in various
parts of the Great Basin and especially in Railroad Valley,
Nye County, Nevada. In that vicinity the existence of a
buried saline body was suspected, and the prospecting took
the form of drill holes designed to reach and explore the sup-
posed saline horizon. Five of these holes were located on
the mud flat or play a left by the ancient lake which once
occupied the valley, and these five holes were sufficiently
alike in materials penetrated and in general conditions to be
possible of discussion together. Although the general
conditions surrounding the work were somewhat unusual,
it is possible that the cost data of the accompanying table
may have some general interest. The prospecting proved
negative, so far as potash is concerned, and has been dis-
continued.

The work here reported was done between June 20 and
November 10, 1913, but during this period there were two
shutdowns aggregating 45 days, leaving a total of 99 days'
actual work. Field operations were in charge of D. H.
Walker, superintendent of the Railroad Valley Company.

Railroad Valley is southeast of the center of Nevada in
a sparsely settled desert country without towns, railroads
or other facilities. All supplies for the work were hauled by
wagon or auto truck from Tonopah, 120 miles west, or from

Chemical engineer, 1105 Madison Ave., Baltimore, Md.

183



184 DRILLING FOR PLACER GOLD

Ely, 75 miles northeast. Drilling was by the rotary jetting
method, using a rotary attached to a steam-driven Keystone
portable rig No. 5 . Water circulation was maintained by two
steam pumps supplied by a separate boiler. The entire outfit
was already in the possession of the company and cost ap-
proximately $7000, including drill rod, all tools and general
equipment, also camp equipment consisting of four tents,
boarding house, office, wagons, water tank, etc. No deprecia-
tion or interest on this equipment has been included in the
costs given. The holes were 5H inches in diameter and were
not cased except for 20 to 50 ft. at the top.

The materials penetrated were essentially the same in all
five holes. The upper portions were in smooth clays with
little or no sand. The hardness was somewhat variable and
a few cemented layers were encountered, but never of such
induration as to create serious obstacles to drilling. In
their lower portions holes No. 2 and No. 6 encountered beds
of solid, crystalline gaylussite 1 alternating with beds of clay.
The crystalline material was fairly hard and drilled like soft
sandstone or shale. Similar beds were encountered but not
entered by hole No. 4. The thicknesses of the beds pene-
trated by the individual holes are given in the table.

The analysis of costs given in the table requires a word of
explanation. "Moving" includes the cost of transporting
the rig and equipment to the site of the hole, setting up, and
preparing for drilling. In the case of hole No. 2, this item
covers the cost of moving the rig to the mud flat from a for-
mer location a few miles north. The expense of this first

^he mineral gaylussite is the hydrous double carbonate of sodium and calcium
(Na2COs CaCOs 5H2O). It is a member of the saline series for which search was being
made. For details concerning the occurrence see Free, "Min. and Sci. Press," Aug. 2,
1913.



DRILLING FOR PLACER GOLD



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186 DRILLING FOR PLACER GOLD

moving was much increased by continuous bad weather.
Water supply for drilling and for the boilers was a matter of
extreme difficulty. No water was available at or near the
drill sites and preliminary 100-ft. holes had proven dry.
When a preliminary 250-ft. hole (sunk with hauled water) at
the site of hole No. 2 also proved dry, it was decided to bring
water by ditch from an artesian well seven miles north.
Water supplied by this ditch was used for all subsequent
holes. In the table the item of water-supply for hole No. 2
includes the cost of the main ditch and of all preliminary
work. For the other holes only the cost of ditch mainte-
nance and of necessary extensions is included. The cost for
hole No. 3 is high because the extension of the ditch to it
had to be carried through a sand ridge nearly a half-mile
wide and several feet high.

The item of drilling includes the actual cost of drilling
only. The usual crew was: One driller, one helper, one
fireman and one sampler. . Occasionally two helpers were
needed. Usually there were two drilling shifts of ten hours
each, the firemen working three 8-hour shifts and looking to
the pumps during the 4-hour shutdown. For a part of hole
No. 2 three 8-hour drilling shifts were used. In addition,
one or two men were employed on repairs and general
mechanical work and one to three teamsters were hauling
drinking water and supplies and keeping the ditch in order.
The wage scale was $6.50 to $5.00 for drillers and $5.00 and
$4.50 for helpers, fireman and teamsters, all on the basis of
an 8 -hour day with pay for overtime at the same rate.
Lodging in tents was furnished free. The boarding house
was run by the company and a charge of $1.00 per day was
made for board. The deficit on the boarding house appears



DRILLING FOR PLACER GOLD 187

under general expense in the table Teams were hired at
$7.00 per day for team and driver and $5.00 per day for
extra teams, not found. Fuel was wood, no other being
available at reasonable cost. It consisted largely of scrub
pine and juniper, and was cut and delivered by contract at
from $10.50 to $12.00 per cord.

General expense includes all items which extended over
the whole work and cannot be assigned with accuracy to
the different holes. These items have been totaled and the
total divided between the holes on the basis of the working
time for each hole. The item for communications includes
the maintenance of the company's automobiles and the hire
of other automobiles when necessary. The employer's
liability insurance is that required by the law of Nevada.
The item for chemical work covers the cost of an accurate
chemical control of the drilling, this being necessitated by
the object of the work. It includes the salary of a chemist
at $7.00 per day and the expense of the field laboratory.
The laboratory equipment was borrowed from the general
laboratory of the company and is not charged for. It would
have cost about $300 to duplicate it.



SUCCESSFUL SALTING OF ALLUVIALS

By C. S. Haley

In attempting a disquisition upon this subject, one is
minded to take pattern after the famous essay upon snakes
in Ireland, which, as will be remembered, began with the
pertinent statement, "There are no snakes in Ireland."
By the same token, then, there is no such thing as successful
alluvial salting, provided: that the examining engineer is
honest; that he takes the care, either through his own per-
sonal knowledge, or through some absolutely dependable
recommendation, that all persons coming in direct contact
with the handling of his samples are either honest or directly
under the eye of some one who is ; and that he use ordinary
care, vigilance, and common sense in checking up the results
of his sampling.

PRELIMINARY EXAMINATION OF ALLUVIALS

For an instance, I will take the easiest conditions for
alluvial sampling; preliminary examination of an ancient
river bed with a view to hydraulic installation. If the
deposit is salted, it may lead to the expense of a more care-
ful and, in inaccessible localities, more costly final examina-
tion, the result of which might mean a great loss of prestige.
In a case of this sort, the examining engineer is apt to make
the trip alone, or with one assistant at most ; as in all prob-
ability his natural inclination, made pessimistic by force of
circumstances and experience, is to believe that he is going
on a wild goose chase, and should be accomplished with as
little loss of time and money as possible.

188



DRILLING FOR PLACER GOLD 189

Arriving at the neighborhood of the property, it is worse
than useless for him to attempt to conceal the nature of his
business. In these our United States, so neighborly is the
interest felt in all the operations of our brother, the chances
are that the proprietor of the hotel in which he rests his
stage -worn bones on the first night of his journey, has been
telephoned in advance of the nature of his errand, and in the
course of his evening's wait he will have all sorts of informa-
tion gratuitously offered him. If, however, our engineer be
not too young he will not shun this information thus thrust
upon him, but may derive a great deal of keen amusement
therefrom. For in even the most isolated mountain com-
munities the knockers thrive as well as the boosters, and he
is very like to hear a composite description of the property
which he proposes to examine which will be very like to a
cubist picture ; viewed from one angle, a radiant vision of a
glorious dawn ; from another, a dark-brown taste on a foggy
morning. From such an extreme double characterization,
by noting the points overemphasized, he can often deter-
mine a course of action, subject to modification on the
ground, which will perhaps aid him to the saving of much
time. On the other hand, he may decide it best to let it all
pass with a "warming of the head", as our Latin -American
friends very aptly put it, and forget all about it.

Arrived at his destination, and well aware that the object
of his trip is a matter of discussion to the entire country-side,
it may be well that he does not look upon the men whom he
hires to attend to the rougher portion of the work as being
like unto Caesar's wife. It may be necessary to run an open
cut into the bank, and down along the rim of the channel ;
or, in the case of a working face, to strip a cut from top to



190 DRILLING FOR PLACER GOLD

bedrock. In all of this work, there is the easiest chance in
the world to salt samples, provided that the engineer is care-
less and easy going. On the other hand, if he appears to be
very insouciant, the chances are that by keeping a watchful
eye beneath such an appearance, he can detect much more
than if he preserves the air of extreme vigilance. Most
salting in such places is very clumsily done. For instance,
if you give a man a sample to pan down for you (intending,
of course, to pay no attention to the result), you may ob-
serve him smoking with his pipe tipped sideways over the
pan, or spitting tobacco juice nonchalantly into the pool in
which he is panning. But this kind of thing should never be
noticed openly. Simply give the man enough rope, and he
will hang himself, and you will avoid a great deal of un-
pleasantness, and possibly the necessity of doing, or receiv-
ing, physical harm. One should always remember that the
last laugh comes with the report. And, no matter who is
handling the manual work of the sampling, always take
check samples yourself, from a face exposed by yourself, and
pan them yourself, with nobody else within five feet of you.

AN UNSUCCESSFUL ATTEMPT

So much for this type of sampling, which is very simple,
and does not necessitate, in the case of an experienced engi-
neer, any weighing of samples. In connection with this
work, I am minded of a tale they still tell in Yreka of two
gentlemen of fortune who attempted to dispose of a worth-
less placer claim to a Chinaman! After very carefully dis-
posing of about five hundred dollars worth of wash gold
about the exposed face of the workings with a shotgun, they
offered the property to Wun Lung, who had recently dis-



DRILLING FOR PLACER GOLD 191

posed of his laundry and pi-gow house, for five thousand
dollars cash. Wun Lung very cheerfully consented to enter
into negotiations, but requested a day to work the property,
to determine its worth. This was, of course, readily ac-
corded him. At the end of the day, the prospective pur-
chaser expressed himself as very well satisfied, but wished to
wait two more days before paying over the five thousand.
With the lure of easy money in their eyes, our gentlemen of
fortune readily assented. On the time appointed, however,
the Celestial failed to materialize; in fact, he could not be
found in the town. The owners of the property, stricken
with a sudden panic, went down to their diggings, and found
their worst fears realized. The carefully scraped banks
showed them whither had departed their $500 worth of dust,
and they returned to town to walk in the virtue of the
chastened.

This kind of thing is, of course, clumsy; so clumsy that it
often defeats itself; as in a case mentioned in The Mining
Magazine some years ago, where a young man went out to
sample a gravel property, and, in spite of the fact that the
promoters managed to slip at least ten cents worth of gold
into every pan that he took, he reported the property as
valueless simply for the reason that he panned all the gold
out and even had no black sand left at the end of his
panning !

KEYSTONE AND EMPIRE DRILLING

In the case, however, of Keystone and Empire drilling,
much more artistic work can be done. For this reason, the
panner on the drill, or at least one of them, should always
be a man absolutely trustworthy and personally known to
the examining engineer. In case of any irregularity on the



192 DRILLING FOR PLACER GOLD

other shift of the drill, it may always be checked by the work
of the absolutely trustworthy shift. One very ingenious
method of salting a Keystone that has come under my notice
has been the plastering of the drill rope with mud containing
plenty of No. 3 colors. In this manner the de trop gold
was carefully and evenly distributed throughout the hole.
A watchful drill-runner, who felt the fine flakes of mud drop-
ping round him as they dried, spoiled this little plan very
effectually, however.

A drill fireman with the tobacco habit spoiled his game
once by spitting too consistently into the box as he lowered
or raised the sand pump. The clumsiest attempt that I
know of in this connection was the deliberate spilling of gold
on top of the ground after the machine had been set up and
the careful salting of panning tubs and boxes. The simple-
ton did not even take the trouble to use the same type of
gold that was ordinarily found in the bar !

DRILL SAMPLING

In drill sampling, however, there is this big advantage
over open-cut sampling; that you have a continual check
on the weight of your gold by the panners' log. In open-cut
sampling, where possibly samples are only weighed once in
two or three days, unless the samples are very carefully
guarded, it might be very easy to augment the sample; and,
as the colors have only been scanned once, and then as a
lump sum, a careful job might raise the value of the property
several cents on the yard. But in either case, until all
samples are weighed up and checked, the utmost care
should be taken in guarding them. Usually, in the case of a
property extensive enough to justify a Keystone examina-



DRILLING FOR PLACER GOLD 193

tion, the amount of money involved is big enough to induce
men of a certain type to take extraordinary chances.

Of course, in the long run, the most effective way of salt-
ing alluvial, as well as other property, is to buy the examin-
ing engineer; but this, too, presents its difficulties. If the
report is to be worth anything in the eyes of practical min-
ing men, it must be made by an engineer of standing. And,
in most cases, that standing is the result of long years of
honest work and toil -won experience. Therefore, the man
who would barter it, even if he would barter that incom-
parably more priceless thing, his self-respect, would prob-
ably demand so high a price that the promoter's profit
would be more than wiped out. For of necessity, to a man
who has lived an honest existence as far as the maturity of
his life, the prospect of not being able to hold his head high
for the balance of his career, is hard to assess to him in
financial terms.

In conclusion, one of the most effectual methods of salting
a gold mine that ever came under my experience, was not
done with gold, but with frogs! The promoter of the prop-
erty, which was once a famous producer in "the days of
old", etc., was making a strenuous effort to sell a worked-
out mine. His prospective buyers were Frenchmen, and
the whole incident came under my personal observation.
The price was moderate, the gold was fairly evenly distri-
buted, and there was a fair chance to sell. However, in-
stead of making the mistake of trying to prove the impossi-
ble, my friend left the subject of available and workable
ground strictly alone, and expatiated on the value and
beauty of the place as a summer camp. Then he led his
buyers down* to a deep and spacious pool of stagnant water



194 DRILLING FOR PLACER GOLD

in the bottom of an abandoned, worked-out diggings. It
was a sort of a frog concentrate, and the rest of the mine,
from a frog standpoint, was not to be judged by it. At the
opportune moment, nets were produced, and before his
clients left that summer afternoon, they were begging him
to accept a check to bind the bargain.



DRILLING FOR PLACER GOLD



195



(SPECIMEN)

FIELD LOG



.Property



Line No Hole No

Date Commenced .... ....192 Date Finished 192.



Depth
in
Feet


Estimated
Weight of Gold


FORMATION


CORE


REMARKS


SIZE


Before


After


1


2


3













































































































































































In Charge




























Driller






























Fanner

















Total depth .feet



Bedrock.



..feet



Water level.... .feet



T. Tailings

F. Fine

C. Coarse

V. Very



ABBREVIATIONS

S. Sand
G. Gravel
Cl. Clay

Sm. Some



St. Sticky

Md. Medium

M. Much

L. Loose



DRILLING FOR PLACER GOLD 196

RECORD OF FORMATION

USED IN CONJUNCTION WITH LOG BOOK



No. of Hole



Date,.



...192



..Contract



.Tract



DEPTH


NO. OF COLORS


FORMATION


REMARKS


Feet


Size
1


Size
2


Size
3










*




























5








































LOCATION


10








































15
































In Charge










20








Prospector



Total Depth Feet. Bedrock Feet. Water Level Feet.



PITTSBURGH. PA.






THIS BOOK IS DUE ON THE LAST DATE
STAMPED BELOW



AN INITIAL FINE OF 25 CENTS

WILL BE ASSESSED FOR FAILURE TO RETURN
THIS BOOK ON THE DATE DUE. THE PENALTY
WILL INCREASE TO 5O CENTS ON THE FOURTH
DAY AND TO $1.OO ON THE SEVENTH DAY
OVERDUE.

3GT 13







Rik cm. MAY 1 4 tS79

Ocr 28 J 939 doV 2 5 1980 '






MAR 241941

JUL 4 1946 ,
II



OUL DEC I



LD 21-50m-8,-32



BERKELEYLIBRARIES




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