IMineceltees Zone GEESE E
oustteaetaASS Perry tienen

t 2 ye

SCALE IN FEET.

Figure 11. - Vertical sections through drill holes, Collier mine, Calaveras County.


shaft was continued to a depth of 58 feet, where two short drifts were
driven along the shear zone. In 1918, two cars of complex ore was shipped
from the shaft at a financial loss. In 19ho, a shipment of 68 tons from the
dump was reported to have assayed 0.27 ounce gold, 7.07 ounces silver, 1.7
percent copper, and 10.6 percent zinc +13/ The smelter paid only for the
precious metals and the copper.

In September 1941, the owner, Mrs. Violet Likens, 2265 California Street,
San Francisco, Calif., leased the property for 10 years to Jack B. Rice and
Ernest A. Vogt; 407 Montgomery Street, San Francisco, Calif. They constructed
a road to the mine and started production in May 1943. From that date to the
cessation of operations in July 1944, 5,507 tons of ore with the following
analysis was produced; 8.75 to 13.46 percent zinc, 1.17 to 1.90 percent
copper, 0.26-to 0.91 percent lead, 0.070 to 0.112 ounce gold, and 2.94 to
4.92 ounces silver per ton.14/

Physical Features and Commmications

The Collier mine is in the southwestern part of Calaveras County, Calif.,
and is easily reached by automobile over hard-surfaced highways and 3 miles of
dirt road. Farmington, the nearest shipping point, is on the Southern Pacific
Railroad, 17 miles distant. Copperopolis lies 11 miles to the east.

The property consists of a patented lode claim containing about 7-1/2
acres. It is at an altitude of 950 feet on the western slope of Gopher
Range. Most of the land in this district is used for grazing. On the upper
slopes are. scrub oak and California oak of moderate size, but they are
unsuitable for use as mine timbers. Weter is scarce in summer, but enough
water accumulated in the bottom level of the mine for diamond drilling.
Climatic conditions are typical of the Mother Iode district.

Description of the Ore

The deposit, consisting of two.lnown ore. shoots about 800 feet apart,
occurs in a shear zone in the typical metamorphosed volcanics of the Foothills
Copper Belt. These siliceous ores are the sulfide replacement type in a shear
zone that strikes northwest and dips northeast. The hanging wall is a hard,
massive greenstone, and the footwall is schist.

The north ore shoot was mined in the early sixties. Surface indications
of this work consist of only two depressions where shafts are caved and
entirely obscured by overburden. From an old map, it appears that one vertical
sha?t was 112 feet deep, and the length of the ore shoot was 200 feet along the
shear zone. No information on the thickness of the vein is available, but it
is reported that it was mined to the 100-foot level.

The south-ore shoot was mined through an inclined shaft 174 feet deep.
It ranged from 2 to 7 feet in thickness, extended 180 feet along the shear
zone, and pinched to an unminable width on the 167-foot level. This shoot,
now mined, raked to the northwest. Ore was taken from the back of the inclined
shaft. and the shaft..pillars,.no support.-having been. left for the shaft.

TS/B. A. Vogt, WOT Montgomery Sts, San Francisco.
E. A. Vogt, 407 Montgomery St.,-San Prancisco.

4033 -3-


American Eagle Mine (Cont'é.)

Hole: AE-3 Depth: 496 ft.
Locations 1935 .N.; 1245 w. Dip: -
Elevation of collar: 1,329 ft. Bearing: N. 89° w.
H Analyses

Footage (Size of Core Sludge
From: | oz /|Feet | core | Cu, percent | Zn, percent | Au, oz.) Ag, oz. |Cu, percent, Zn, percent Au, oz. Ag, o2-
205° [206 | 1.0 Tax 0.02 2.8 0.020 | 2.20 i
206 | 207.4) 14) ax 05 | 2.2 065 | 3.20 | |
206 | 209 | 3.0]; ax | | | 0.02 04 | 0.015 | 3.50
209 | 209.1 | 0.1 | AX 03 A | ! | \
209 =| 210 | 1.0) Ax | | 05 344 +020 | 2.20
210 211.6! 1.6) Ax 02 1.2 +030 | 2.35 |
210 |216 | 6.0} ax | | | | +10 2.8 2025 | 2.50
216 |216.8; | Ax #020 | “Lj 020 | 2.60 | en
216 | 217.5 | 155 | AX | i | i | Oh 5 oro | 2.50
217.5 220.6 | Bol) AK oh | *1 | 15 | 3.00 | | |
217.5 | 221 3.5' ax | : i | “9 | ¥.1 L015 | 3.75
*Less than.
Hole: AE-4 Depth: 492 rt.
Location: 1790 N.; llo4w. Dip: 51°
Elevation of collar: 1,331 ft. Bearing: S. 1° We

j | Analyses

Footage {Size of | Core i Sludge
From: ; To: jFeet_| core | Cu, percent Zn, percent |Au, oz. | Ag, oz. |Cu, percent : Zn, percent |4u, oz. ‘Ag, oz.
210.57253.5 | 3.0) ax | 0.03 0.1 | Brace | None I |
243.5 | 245.6 | 2.2.) AK | oT | 2 | | 0.20 i |
245.6 [248.3 | 2.7) ak | #02 j 2 |" | 20 i i
261.5 | 264.5] i i ' i H | |

he | AK | #02 | 3 | TM 4 20 | i

265.5 | 266.7) | I | | | i ! |
264.5 1265.5 [1.0 | ax | *.02 | el 10.010 200 | :
*Less than.
4033 - 60-


The schistosity in general strikes slightly east of north and dips
eastward from 75 degrees to vertical, whereas the included shear zones strike
north or slightly west of north. Within the schist belt, and most noticeable
to the west of the prominent shears, are zones of silicification of varying
dimensions and intensity. Numerous short, narrow streaks of gossan are in
evidence in many places, as are zones in which barite is noticeable. Veins
and short stringers of white quartz also show in the schist, frequently
cutting the schistosity. Oxidation of the minerals apparently extends
downward for a considerable distance, as the walls of the adit-level workings
show evidence that.the soluble sulfates have reacted strongly upon the rocks.
Underground in the main zone of alteration, malachite and azurite stains
color the formation in places, and at the bottom of the winze a band of friable
sulfide ore exists. This band, consisting of sericite schist, pyrite,
chalcopyrite, sphalerite, covellite, barite, and quartz, is about 4 feet wide
on the northeast wall, where it appears to have converged. Mineralization on
the southwest wall indicates a splitting of the vein into several stringers,
and a sample taken across one stringer 2 feet wide assayed as follows: Copper,
8.27 percent; zinc, 9.65 percent; lead, 0.30 percent.

Work Performed by Bureau of Mines

Following preliminary investigations of the property, diamond drilling
was recommended. Contract drilling operations were carried on from January
3, 1944, to March 31, 1944, and seven holes aggregating 2,804 feet were bored.
As shown in figure 13, all holes were drilled on the American Eagle claim, and
their penetrations crossed various horizons of the shear zone below the ore
exposures in the adit level. With the exception of hole AE-7, drilling was
for the most part in schist that had undergone varying degrees of
sericitization. Over-all core recovery averaged 65.76 percent.

Mineralization was encountered in holes 1, 2, 3, and 7. The combined

assay results from core and sludge are shown in figure 13, and additional
data are listed in the appendix.

4033 - 16 -




Hole CH-5 (Cont'd.)

Footage _ Percent
From Zo core recovery Description
436 AY3, 90, Gray siliceous material, quartz?, and
, scaley

452 4.78 59 Green, silicified amphibolite; scattered
scaley pyrite; some intervals gray,
siliceous material (quartz?) .

478 4.90 62 Gray-green silicified amphibolite; some
masses of dark-green chlorite.

go 495 66 Siliceous breccia.

495 496 63 Porphyry.

496 500 63 Gray-green silicified amphibolite.

Grayhouse Mine
A, - Bureau of Mines Drill-Hole Logs
Hole GH-1
Location: 548 feet East of Spring. Bearing: S. 71° W.
Elevation of collar: 25.5 feet above gossen Dip: -4
at spring. BX: 60-60 ft.
Depth: 6833 feet AX: 80-833 ft.
MX: 0-60 ft.
Footage * Percent
From Do core recovery Description
Co) 60 (o) No core, sludge shows clay, gravel, and
schist.

60 65 17 Iron-stained chloritic schist.

65 80 37 Green chloritic schist, some red (hematite?)
streaks.

80 86 60 - Greenish-brown, highly chloritized schist,
containing epidote, hematite, and dark
chlorite.

86 87 60 Chloritized conglomerate, black cementing

. material, pieces of white quartz.

87 100 kg Greenish-brown, highly chloritized schist
containing epidote and hematite.

100 137 61 Brownish-green chloritized schist containing
much epidote, some hematite, and little
white quartz.

137 138 38 Iron-stained light-green schist.

138 193 4g Brownish-green chloritized schist, some

4033

intervals have a definite leached appear-
ance, epidote is abundant in veinlets and
disseminations; few tiny quartz veinlets
and iron-stained streaks (hematite?).

- ho -


Footage

Erom To

ho 5h

5h 92

92 140
1ho 160
160 175
175 215-5
215.5 255
255 275
275 289
289 299
299 344
Buh 369
369 380
380 409

4033

Percent
core recovery

oh

7

83

88

87

99

69

100

78
97
85

Hole N-3 (Cont'd.)

Description

Pale-green silicified amphibolite schist,
mich epidote disseminated throughout, few
small veinlets of white quartz.

Dark grayish-green amphibolite schist highly
banded with hematite, few tiny veinlets of
epidote and white quartz, somewhat
chloritized from 68 to 84 feet.

Green amphibolite schist, considerable
epidote disseminated and in veinlets, few
small. veinlets of white quartz, this inter
val banded occasionally by hematite and
tiny calcite veinlets.

Pale-green amphibolite schist, 2-inch quartz
veinlet at 150 feet, few tiny epidote and
calcite veinlets.

Green amphibolite schist, numerous veinlets
of quartz, few tiny veinlets of calcite,
scattered cubes of pyrite, this interval
slightly chloritized, a seam of pyrite at
174 feet.

Pale grayish-green amphibolite schist
(uralite), few stringers of quartz and
calcite, considerable pyritization, some
chloritization on planes of schistosity.

Grayish amphibolite schist (uralite), few
small quartz and calcite veinlets, some
chloritization on planes of schistosity.

Light, pale-green amphibolite schist,
several 3 inch veinlets of quartz, some
calcite and epidote disseminations.

Green amphibolite schist, disseminations
and veinlets of epidote, few specks of
pyrite, some chloritization on planes of
schistosity.

Greenish-gray amphibolite schist (uralite),
slightly chloritized, veinlets of quartz
and epidote.

Greenish-gray amphibolite schist (uralite) ,
silicified, mich epidote disseminations
and veinlets at 317 feet, few very small
Quartz veinlets, some scattered pyrite.

Green chloritic schist, mich epidote in small
veinlets.

Light-green chlorite schist, many veinlets
and disseminations of epidote.

Light-green schist considerably chloritized,
few fine veinlets of quartz and calcite,
some epidote.

~ Qh -


Location: 429.N. 865 E.

Elevation of collar:

Depth: 800 ft.

Footage
From Zo
0) 36
36 81
81 82
82 101
101 203
203 236
236 256
256 286.5
286.5  3h6
346 362
32 370
370 383
383 heh
heh hes
hea5 439.7
439.7 566

4033

31 ft. above collar Dip: -73°
of main shaft. Core size, feet:
Mk: 0-15
BK: 15-40
AX: 40-800
Percent
core recovery Description

ho Surface altered schist.

B Pale-green amphibolite schist, few quartz
veinlets.

97 Rose quartz.

7 Amphibolite schist, some disseminated epidote.
some chloritization or schistosity planes.

kg Dark-green amphibolite chloritized schist, a
few quartz veinlets, fine bands of pyrite
108 to 111 feet.

48 Pale-green chloritic schist with some epidote
veinlets and disseminations of epidote.

52 Green chloritic schist, considerable banding
of epidote and hematite.

61 Pale-green chloritic schist with mich dis-
seminations and veinlets of epidote.

86 Pale~green amphibolite schist, a few quartz
veinlets, much epidote disseminations,
some tremolite on certain planes of
schistosity.

38 Pale-green amphibolite, some very massive,
mach epidote disseminations, minor amounts
pyrite.

52 Dark-green amphibolite schist, many quartz
veinlets, cube pyrite noticed.

68 Dark-green amphibolite cut by many quartz
veinlets, much disseminated, and veinlets
of epidote, part of zone chloritized, one
foot of quartz at 374 feet.

70 Dark-green chloritized schist cut by quartz
veinlets, numerous cubes of pyrite at
certain intervals between 406 to 42h feet.

83 Lavender-colored schist, probably colored by
iron.

83 Dark-green amphibolite schist cut by veinlets
of quartz, disseminations end veinlets of
epidote, some pyrite at 436 feet, some
areas somewhat chloritized.

92 Amphibolite schist cut by epidote and quartz

Bearing: S. 67° 45" w.

veinlets.

- 22-


Hole N-4 (Cont'd.)

Footage Percent

Erom To core recovery Description

510 569 19 Green amphibolite schist, shattered, epidote
veinlets, little quartz, few specks pyrite
between 568 to 569 feet. .

569 609 é2 Light gray-green, Silicified, amphibolite
schist, some epidote in masses and tiny
veinlets.

609 €27 71 Gray-green massive amphibolite schist
(uralite?) .

627 641 AD Gray-green amphibolite schist, scattering of
shaly pyrite, fractures filled with dark-
green chlorite.

6421 643 34 Blue-black argillite with scaly pyrite.

643 665 56 Light gray-green amphibolite schist, 4-inch
white quartz at 648 feet, somewhat
chloritized, parts leached.

665 678 80 Gray-green amphibolite schist.

678 679 95 Highly friable, talcy, light-gray schist
having a leached appearance.

679 689 80 Green amphibolite schist, scattered scaly
pyrite.

689 700 88 2-inch argillite at 692, balance light-green
amphibolite schist, slightly chloritized
on planes of schistosity.

Hole N-5
Location: 796 N., 1148 5. Bearing: S. 57° 30' W.
Elevation of collar: 28.7 ft. above collar Dip: -73°
of main shaft. Core size, feet:
Depth: 1,076 ft. NX: 0-6
BX: 6-20
AXs 20-1076
Footage Percent
From To core recovery Description
fo) 20 29 Surface altered amphibolite schist with con-
siderable iron-stained veinlets of quartz.

20 71 hg Pale-green amphibolite schist, few quartz
veinlets, some intervals silicified and
others somewhat chloritized on planes of
schistosity.

71 101 60 Green amphibolite schist with occasional

quartz veinlets, epidote in scattered
veinlets, minor amounts of pyrite scattered
near the quartz veinlets.

4033 - 28 -


Hole N-5 (Cont'd.)

Footage Percent
From Zo core recovery Description
1038 1040 90 Green amphibolite schist with fine bands of
pyrite (mundick of the local miners?).
loko 1055 66 Green amphibolite schist more or less

silicified, considerable epidote dissemi-
nations, some parts chlori d and some
intervals show brownish coloration probably
due to hematite, few tiny quartz veinlets.

1055 1076 100 Green amphibolite schist considerably
chloritized, some epidote disseminations ,
few tiny veinlets of white calcite from
1,056 to 1,076 feet.

Copper Hill Mine
A. = Bureau _of Mines Drill-Hole Logs

Hole CH-1
Location: 1200 N., 1200 E. Bearing: S. 49° W.
Elevation of collar; Level with collar =50°
of main shaft. 8-ho ft.
Depth: 730 feet. ‘ 40-270 ft.
0-8 ft.

EX: 270-730 ft.

Footage Percent
From Qo core recovery Description
ie} 36 37 Surface altered amphibolite, some iron stain
on fractures, few tiny quartz veinlets.
36 57 67 Light-grcen amphibolite, few very smll
quartz veinlets.
57 85 64 Gray-green amphibolite, some fractures filled
with dark-green chlorite.
85 102 yy Pale-green amphibolite, some of porphyritic
texture.
102 149 5ST Gray-green porphyry, fairly massive; light-

colored, irregular bounded phenocrysts

ground mass is uralite and some chlorite;

few white quartz veinlets, few grain pyrite,
. also few veinlets of epidote.

149 199 91 Pale gray-green amphibolite, some sm11
masses of dark-green chlorite-matrix is
apparently largely uralite and quartz-vein-
lets of quartz and epidote and at 188 feet
a 2-inch vein of white quartz containing
cubes of pyrite and little white calcite.

4033 ~ 32 -


Hole N-1 (Cont'd.)

Footage Percent

Erom Zo core recovery Description

hh 165 60 Schist at 150 ft. has been crushed,
brecciated, and recemented with quartz and
calcite; otherwise same es above.

165 172 48 Green chlorite schist, epidotized zones,

. some quartz veinlets, minor pyrite.
172 192 41 Pale-green chlorite schist, bands sericite

schist, some of which are silicified,
epidotized, and sparsely pyritized.

192 222 69 Dark-green chlorite schist, some zones
epidote and quartz with fine pyrite near
white quartz veins.

222 2he ae Pale-green chlorite schist, silicified and

containing pyritic disseminations, tale in
thin layers along local planes of movement.

eke 252 72 Green chlorite schist, little quartz vein-
lets, some pyrite.
252 291 51 Epidotized chlorite schist, numerous thin

silicified bands showing some calcite and
pyrite, some talc on certain slippage sur-
faces, a thin veinlet of quartz and fibrous
greenish-white tremolite noticed at one
place.

291 311 Le Green chlorite schist slternating with dark
argillaceous bands, many of which contain
hematite-epidote and silica introduced-some

pyrite.

311 321 48 Green schist of uralite, chlorite, and some
introduced epidote.

321 341 71 Pale-green amphibolite schist largely of

fibrous uralite and green chlorite, veinlet:
of quartz, calcite, and white tremolite,
zones of epidote, small lenses of pyrite.

341 351 72 Green chlorite schist, much calcite, little
quartz and pyrite.
351 371 oT Pale-green amphibolite schist, spotted appear-

ance, Quartz, calcite, and green epidote
carrying pyrite.

371 431 TT Pale-green amphibolite schist, lenticular
masses of dark-green chlorite, occasional
crystals of pyrite and lenticular veinlets
of white quartz; epidote is present,
especially where large amounts of quartz
were introduced.

431 Lise 80 Epidotized green schist with large amounts of
introduced silica.
Wha 451 53 Uralite schist, several 3-inch and 6-inch

zones of chlorite schist.

4033 - 20 -






Location: 1810 N., Shh E.

Elevation of collar:

Depths 500 feet.

Footage
From Do
° 26
26 45.5
45.5 88
88 128
128 146.5
146.5 175
175 233
233 23h
234 263
263 264
264 302
302 352
352 389
389 413
413 436

4033

Hole CH-5

Bearing: S. 53-30° W.

Below collar of Dip: -45°
Jackass shaft. BX: 6-20 ft.
AX: 20-500 ft.
NX: 0-6 ft.
Percent
gore recovery Description

63 Altered amphibolite.

50 Pale grayish-green amphibolite; fractures
iron-stained; a few tiny quartz veinlets,.

88 Pale greenish-gray, silicified amphibolite
with a few tiny quartz veinlets and 6-inch
intervals of porphyry of same color; the
phenocrysts are cream-colored and have no
regular boundaries; the matrix is aphanitic.

4g Pale greenish-gray, silicified amphibolite,
few tiny white quartz veinlets, small
fractures filled with dark-green chlorite.

63 Pale greenish-gray, silicified porphyry; the
Phenocrysts are cream-colored and have no
regular boundaries, a few white quartz
veinlets, some fractures appear to be
filled with green chlorite.

92 Pale-green, silicified amphibolite, a few
tiny white quartz veinlets, occasional
breaks show scaley pyrite.

8h Light grayish-green, silicified amphibolite,
ea few tiny white quartz veinlets, scattered
scaley pyrite.

87 Silicified graywacke.

85 Pale-green to green silicified amphibolite;
scattered scaley pyrite.

o7 Silicified graywacke.

90 _ Light-green silicified amphibolite, a few
tiny quartz veinlets, one of 6 inches at
297 feet considerable disseminations of
fine pyrite.

76 Pale-green silicified amphibolite; new
fractures of core show scaley pyrite.

8 Grayish-green silicified amphibolite,
considerable scaley pyrite and some
disseminations of pyrite.

76 Mineralized zone, siliceous amphibolite,
copper, zinc, and pyrite, very low-grade,
not ore.

65 Pale grayish-green, highly silicified

amphibolite, scattered pyrite.

-4l-


INVESTIGATION OF WEST BELT COPPER-ZINC MINES, EL DORADO,

AMADOR, CALAVERAS, AND MARIPOSA COUNTIES, CALIF.
by

Frank J. Wiebelt,2/ W. C. Saborn,2/ R. R. Trengove, 2/
and Spangler Ricker2/

CONTENTS

Introduction and summary.
Acknowledgments....
General features.
Ore deposits...
Newton mine.........0.
Introduction...
History....esseee
Geology and mine workings........
Work performed by Bureau of Mines
Copper Hill mine....ceceecccccevcvcceces
History..
Geology and mine workings........
Work performed by Bureau of Mines
Gray House mine..
Introduction,
History..
Geology...
Work performed by Bureau of Mines
Constellation mine.....eeseeseeees
Introduction.
History..
Geology..
Work performed by Bureau of Mines..
North Keystone mine......
Introduction......
HIStory. .cccceceeeeeee
General geology and description of deposit..
Mining.....cceeceeee
Milling.......eeeeee
Development and milling costs. .
Work performed by Bureau of Mines....

bas)
©
00 OYANAAAN AARAAVI RHEE OH EEE

1/ Mining engineer, U. S. Bureau of Mines, Region III.

Report of Investigations 4760


Hole CH-1 (Cont'd.)

Footage Percent

Erom Do core recovery Description

hoe 512 oh Dark-gray sericite schist with veinlets of
calcite and epidote.

512 520 72 Grayish-green sericite schist, veinlets of

. epidote quartz and. calcite.

520 585 48 Dark greenish-gray sericite schist with
veinlets of epidote, calcite and white.

585 625 63 Grayish-green sericite schist with veinlets

of epidote, calcite, end quertz, fine
pyrite in seams between 603 and 605 feet.

625 643 7 Gray scricite schist, considerable white
quartz in veinlets, scattered pyrite in
tiny seams or bands.

643 663 87 Gray sericite schist, quartz veinlets;
pyrite in tiny seams is scattered through
this interval.

663 725 29 Gray sericite schist, few veinlets of white
quartz and calcite, scattered pyrite in
seams and disseminations.

725 758 52 Gray sericite schist, white quartz veinlets,
scattered tiny seams and disseminations of
pyrite.

758 822 35 Gray sericite schist, white quartz veinlets,

pyritic disseminations throughout, some
pyrite in tiny seams.

822 833 15 Dark grayish-green schist, tiny veinlets of
quartz, very little scattered pyrite.

Constellation Mine

A. - Bureau of Mines Drill-Hole Logs

Hole C-1
Location: 1155 N., 1246 BE. Bearing: (S. 48-30° we
Elevation of collar; 51.4 feet above collar Dip: -45'
of Berger shaft. BX: 11-60 ft.
Depth: 667 feet. AX: 60-667 ft.
NX: O-1ll ft.
Footage Percent
rom pio} core, recovery Description
fe} 27 25 Yellow-brown residual clay from rock below .L/
27 45, 58 Weathered sericite schist, light buff color.
45 106 53 Sericite-tale schist, very fine-grained,

considerebly weathered (Mariposa slate?).
Angle between cleavage and length of core is
75 degrees.

oc

/ Log by Us 5. Geological Survey, March 1943.

4033 - hk -


Hole. GH-1 (Cont'd.)

Footage Percent

Erom pic} gore recovery Description

193 210 el Light-brown schist containing mich white
quartz.

210 215 he Gray, dense schist.

215 220 ho Light-gray mottled schist and quartz vein-
lets, somewhat chloritized.

220 229 47 Grayish-green schist, some intervals leached
to a porous state, 1 inch quartz veinlet
at 220 feet.

229 230 47 Red cherty material with fractures filled
with calcite.

230 256 30 Gray-green chloritized schist, epidote vein-
lets; some intervals have been leached.

256 260 23 Light-gray siliceous material having a some-
what leached appearance, yet is very hard.

260 270 19 Dark-gray schist (chloritized) with quartz
veinlets.

270 278 5h Gray schist with tiny calcite veinlets.

278 298 19 Greenish-gray schist, epidote, and calcite

" veinlets; a few intervals show hematite
coloration, 2 feet of leached quartz at
298 feet.

298 320 el Gray schist with veinlets of white quartz,
epidote, calcite, and a few tiny ones of
hematite.

320 323 5h Light-gray siliceous schist, white quartz
veinlets.

323 329 20 Dark grayish-brown siliceous material with
some white quartz veinlets.

329 335 43 Gray siliceous schist, mich quartz.

335 3h0 kg Light-gray sericite schist, considerable

. iron-stained quartz at 338 feet.

340 365 ho Gray sericite schist.

365 hor 62 Greenish-gray schist, veinlets of epidote
and calcite, some intervals have a leached
appearance.

hor kg 71 Gray, silicified schist showing veinlets of
epidote, white quartz, and some hematite.

41g 4eg 89 Rusty gray-colored schist,

hag 438 91 Dark-gray, highly silicified sericite schist
with veinlets of epidote, calcite, and
white quartz.

438 YAS, 66 Gray amphibolite schist somewhat porphyritic
in appearance, a few. white quartz veinlets.

ALS 455 56 Much white quartz and some hematite. +

455 4g1 Yh Gray sericite schist with veinlets of calcite
and epidote, some intervals of white quartz.

Kou hoe 43 White quartz and calcite.

4033 - 3 -


Footage
From Do
504. 531
531 534.6
534.6 560
560 D710
570 STT
STT 581
581 610
610 627
627 643
643 667
NOTE:

4033

Percent
core recovery

9

69
67

91

86

Hole C-1 (Cont 'd.)

Description

Variable greenstone, with little schistosity
mixed with green schist with moderate
schistosity. Much of it mottled with
irregular streaks and blebs of lighter-
colored, fine-grained, epidote-feldspar
rocks

White quartz vein.

Moderately schistose greenstone, in part
fragueintal. Color light green to gray;
probably lacks epidote. Several quartz
veins 3 to 10 inches wide.

Dense greenish-gray argillite; locally thin-
bedded; also a few thin, gritty beds.

Massive rock mottled light green and white.
Contains quartz and feldspar, meta-rhyolite

Bedded argillite and grit.

Variable greenstone as at 504 to 531 feet; a
‘little argillite interbedded.

Bedded argillite snd grit.

Mottled greenstone, more or less massive.
Suggestion of fragmental texture. Much
veined with quartz and zoisite?

Rather uniform chloritic greenstone, more
or less schistose. Mottled and streaked
surface suggests original fragments.

A small but persistent sprinkling of tiny pyrite grains is present
throughout the core below 325 feet.

-6-


‘SCALE IN FEET

1000

200

700:

ah
AY ay

ACHAT

\ Nx ages 498.3 1.73 % CU. “ee
enh
ig wo

\ 400.
18.0-8IRIS 1.18 % CU.

Ss

BEHKH

Figure 9. - Sections North Keystone mine, Copperopolis,

Calaveras County.


—100

—200

-300

—400

—500

0.0. Hole CH-

CORE
Footage

Per

510.3-510.5

412

Cent

0.50

1.60

Trace.

515.6 -516.0

0.27

LeX-{0)

040

Trace

527,5-5288]

0.24

0.40

0,40)

5298- 531.0)

O13

3.10

O15

Trace

SLUDGE

1510.5 - 516.0

0.12

Q10

516.0 - 521.0,

0.13

Q10

None

Trace

0.2 feet 4.12 %Cu- 0.50% Zn. & 1.60 ounces Ag,

100 200 FEET
600

SCALE

Figure 5. - Section through drill hole CH-2, Copper Hill mine, Amador County.

West

See appendix for additional data


CONSTELLATION MINE

Introduction

This property is in Lots 3690 and 3690a, being Survey No. 269 in secs. 3
and 4; lots 5 and 9 of sec. 3; and Survey No. 4933 in sec. 3, all in T. 4 N.,
R. 10-E., M. D. Be & Me, in the north-central part of the SW1/4 of the Jackson
Quadrangle, Calaveras County, Calif. It adjoins the Fenn mine on the south
and may be reached by following a surfaced road from Valley Springs to Campo
Seco a distance of 4 miles, thence northwest 2 miles on gravel road. The
nearest rail shipping point is Valley Springs, population 400, on a branch line
of the Southern Pacific Railroad.

The area in the vicinity of the Constellation mine is drained by Oregon
Gulch Creek, a northwesterly flowing tributary of the Mokelume River. The
general physical conditions and topography are similar to those at the other
properties discussed in this report.

History

The Constellation mine has been idle for more than 35 years. A vertical
shaft has been sunk on the southern extension of the east vein of the Penn
mine to a depth of 400 feet. Records show that more than 1,700 feet of
drifting and crosscutting were done on three levels. Underground workings
are inaccessible, and there is no record of production from this property.

The Gonstellation mine is owned by the Constellation Mining Co. and is
now under lease to L. W. Thayer, Inverness, Calif.

Geology

The zone on which this property has been developed lies in a belt of
sericite schist that strikes west of north and dips steeply to the east.
Locally it is called the east vein, and it is a continuation of the east vein
that strikes across the Penn property. The dump shows- some of the material
from the underground workings to be quartz, pyrite, chalcopyrite, and_
sphalerite. Goésan can be traced northward from the shaft to a point near the
crest of a hill, where it is overlain by suriferous gravel tailings.

Work Performed by Bureau of Mines

One hole 667 feet long was drilled on this property; it comprised 11 feet
of "NX" hole, 49 feet of "BK" hole, and 607 feet of "AX" hole. Casing set
totaled 60 feet. Core recovery was 55 percent. Mineralized sections that
would justify assaying were not encountered. Figure 7 shows a plan of the -
workings and location of drill hole. The log.of this hole is given in the
appendix.

NORTH KEYSTONE MINE

Introduction

Work at the North Keystone mine was undertaken by the Bureau of Mines in
cooperation with the Federal Geological Survey for the purpose of finding

4033 -7* .


West Eost

°
Ne a,
aN .R.Hole CH-4
NN :
SN
aN
NEN
ne
'
100
CORE
Recovery [Per Cent Ounces

Footage _in_Feet_[ Zinc | Copper [Silver | Gold
183.0- 183.5] 0.5 9.10| 0.03] Trace | None
1835-1890] 2.0 [33.62] 0.57|20.20| 0.06
189.0- 191.5. 25 O10] 0.06] 0.10] Trace
1915-1936 1.3 [413.32] 1.31] 2.98} 0.02

SLUDGE
Cant

P. rey
| Foctage Recovery? Zine Copper [Silver
1830-189.0| 67 | 26.00] 0.35 | 10.15 }0.0:
190 -193.6| 18 | 13.00] 0.25] 3.80}0.005
re Zone 193.6-2035| 22 | 1o070{ 020] 3.10|0.02
= . . .200.01
‘oot wiate 10.3 tepozs=2i2ol 13 T esol ois] 3.20/00

Average Zinc 22
Areroge Copper Oaks “S"
‘Average Silver 9.31 ounces
Average Gold 0.02 0

208.0-210.7 27 | 2019 Q62} 9.40] 0.01

-200

See appendix for additional data

(°} 50 190 FEET
SCALE

‘
300

Figure 6. - Section through drill hole CH-4, Copper Hill mine, Amador County.





Ore indications were found in holes 2 and 4. Hole 5 was drilled 125
feet to the south of hole 4 but failed to prove an exténsion of ‘the ore body
to this point. The drilling did not intersect any extensioris of the surface
outcrop. ‘

The ore consisted of massive sphalerite containing a high percentage of
silver. The total ore width in hole 4 was 10.3 feet and comprised three
separate intersections at depths of 183.5 to 189 feet, 191.5 to 198.6 feet,
and 208 to 210.7 feet. Both core and sludge recovery were poor. Adjusted
averages gave the following analysis: 22.37 percent zinc, 0.43 percent copper,
9.31 ounces silver, and 0.02 ounce: gold.

Figure 4, shows the surface plan and location of @iamond-drill holes.
Figures 5 and 6 show sections of the only two holes in which ore was intersecte¢.

GRAY HOUSE MINE

Introduction |

The Gray House mine is in sec. 33, Te 5 Ne, R« 10 E., Mount Diablo base
line and meridian, in the north-central part of the swi/h of the Jackson
Quadrangle, Amador County, Calif. It is just across the Mokelume River from
the Penn mine and can be reached from Ione by following the surfaced road from
Tone to Comanche via Buena Vista and Lanche Plana for a distance of 9 miles.

The area in the immediate vicinity of this property drains southeasterly
into the Mokelume River. The hills are moderately rugged and covered with
scrub oak and heavy underbrush. The elevation is about 350 feet above sea
level, and climatic conditions are similar to those at the Newton and Copper
Hill mines.

Histo:

A 200-foot vertical shaft was sunk on this property during the early
activities in the district. In 1906 it was sunk 50 feet farther, and 1,000
feet of drifts and crosscuts were driven. There are no records of any
production from this mine, and workings were inaccessible. It is owned by
Lloyd W. Thayer, Inverness, Calif.

Geology

The zone on which this property has been developed consists of a belt of
Sericite schist and is a northerly extension of the Penn mine schist. Dumps
of excavated material show very little mineral.

Work Performed by Bureau of Mines

One hole 833 feet long was drilled and it consisted of 60 feet. of "NK",
20 feet of “BX", and 753 fect of “AX”. Eighty feet of casing was set. A 45,2
percent core recovery was obtained. The hole was drilled near the entrance of
a large open cut just west of the Buena Vista Lancha Plana road. The log of
this hole is given in the appendix; no samples were taken.

4033 -6-


Record of Diamond Drill Hole Values

American Eagle Mine

Hole No; AE-1 Depth: 426
Location: 1786 N.; 1106 Ww. Dip: - 5
Elevation of collar: 1,331 Bearing: S. 69° W.
i i Analyses

Footage !Size of Core ] Sludge
From: , Tos {Feet core Cu, percent; Zn, percent | Au, 02. Ag, 02. ‘Cu, percent Zn, percentjAu, oz. !Ag, oz.
249.5| 252.7 | 3.2 AX *0 002 { *0.1 Trace None i
250.5} 251.5} 1.0| Ax *.05 *.1 " i "
254.5} 256.3 | 1.8) ax 05 *.1 "| _
313 | 315.5 | 2.5 AX 1h *.1 rn |
315.51 319.5 | 4.0 AX +19 *.1 ; : > 0.08 *0.1 | Trace | None
319.5 | 323 3.5 AX +03 *.1 + H
342 | 342.4 oh AX 05 6.7 0.005 0.30 |
341.4) 343.2 | 1.8 Ax 03 7.15 None 50
343 .2 | 343.8 6 AX Trace 1.21 Trace +10 i
341 | 345 4.0 AX +02 2.30 None 0.0
345 | 349.5 | 465 AX +12 7 ce 5
349.5 | 350.3 8 AX 0.20 *.1 Trace None
349.51.360 . 310.5 AX 25 *.1 Trace None
360 | 362.4 | 2.4 AX 315 HL Bad " an
360 | 366 6.0 Ax 15 a. |. i
366 | 371 5.0} Ex 1h
371 | 374.8 | 3.8 EX | +10 *.1 " ”
371 | 376 5.0 EX ; 10 ¥.1 ” nd
376 1.381 | 5.0; EK | | : uy #1 o | o#
416 her 5.0 | EX { 20 *.1 " {o*

4033 - 5 -


Hole C-1 (Cont'd.)

Footage Percent
From Bo core recovery Description
106 116 47 Same as below, weathered greenish-brown.
116 179 =. kg Chlorite-sericite-talc schist locally

grading to light-green geiss. Abundant
lenticular fragments 1 inch or less in
length in light-green matrix.

179 190 56 Greenish to purplish felsite; green color
due to epidote in part; weak schistosity
contains veinlets of quartz and epidote.

190 262 Ay Chlorite-sericite-talc schist as above.

262 325 83 Fine-grained, dark greenstone with visible
epidote and feldspar. Moderate, persitent
schistosity. Becomes finer-grained down-
ward. Quartz-epidote veins throughout,
some as much as 6 inches wide.

325 380 28 Talcose schist as at 45 to 106 feet. Carries
disseminated pyrite at 327 to 328 feet and
at 336 to 339 feet; bleached at 336 to 339

. feet.

380 413 25 Light-gray, talcose, sericite schist mostly
carrying disseminated pyrite. At 393 feet
it is somewhat silicified and carries
maximum pyrite, perhaps 15 percent. No
other sulfides recognized. Many milky
quartz veins at 393 to 403 feet.

413 486 29 Fine-grained, pale-green sericite schist
with talc. Several zones of light-gray
(bleached?) color. Mostly carries dissem-
inated pyrite in very small amounts.

Locally slightly silicified, but not accom-
panied by additional pyrite. Angle between
schistosity and core is 80 degrees.

486 488 98 Dense-textured greenish-gray felsite,
translucent.
488 498 oT Gray sericitic schist with fine fragmental

texture; disseminated pyrite locally. Con-
tains visible quartz, feldspar, and sericite;
and probably also epidote and chlorite.
Texture suggests arkose or grit, but it may
represent silicified pyroclastic rock.

498 502 96 Heterogeneous greenstone, weakly schistose,

Grades downward into uniform epidote-greenstone

(i.e. lacks schistosity in lower part).

502 504 92 White quartz veins with masses of fine-
grained chlorite.

4033 - 45 -


Footage
Erom ze
Aho 463
463 502
502 539
539 551
D951 589
589 643 65,
643.5 680
680 687
687 701.5
701.5 709
709 728
728 Tho

4033

Percent

gore recovery
17

100

80

70

100

2

53

91

100

100

88

Hole N-3 (Cont'a.)

Description

Pale-green amphibolite schist considerably
chloritized, epidote disseminations and
veinlets, hematite banding between 457
and 459 feet.

Pale~green amphibolite schist all somewhat
chloritized, some epidote in veinlets and
disseminations.

Light pale-green amphibolite schist highly
chloritized, mich epidote disseminations,
tiny cross veinlets of calcite and few
small quartz veinlets.

Pale-green amphibolite schist, somewhat
chloritized, some epidote disseminations
and veinlets, a few tiny veinlets of
calcite and quartz.

Massive, pale-green, amphibolite schist
only slightly chloritized, a few tiny
veinlets of quartz and calcite, little
tremolite at 577.5 feet, this interval has
spotted or porphyritic texture.

Green to pale-green amphibolite schist all
considerably chloritized, few stringers
of quartz, scattering of epidote veinlets
and disseminations, numerous tiny calcite
veinlets, pyrite scattered between 620 and
€22 feet.

Green amphibolite schist considerably
chloritized, 6-inch white quartz at 652
feet and 5-inch at 653 feet, fractured,
occasional specks of pyrite.

Partly silicified, green, amphibolite schist,
veinlets and disseminations of epidote,
few quartz veinlets, some banding due to
tiny seams of hemtite.

Grean silicified amphibolite schist, mch
epidote disseminations and some veinlets,
few tiny veinlets of calcite and quartz,
scattering of pyrite, few 1-inch bands of
dark-green chloritic schist.

Green amphibolite schist, few tiny veinlets
of quartz and calcite, quite mssive.

Light, pale-green, speckled schist {uralite?)
epidote disseminations, few veinlets of
quartz and calcite, occasional specks of
pyrite, interval somewhat silicified.

Light pale-green schist (uralite?), scattered
pyrite, somewhat silicified yet chloritized
on some planes of schistosity.

- 30-




1040.

.
a
“Yt ieee

+ wa ELS Caup H ‘S =

K STATE

{

i

QO

| \
é 1 o
is va
q 1
4 ~
> Ye
i \ H
\ . 1 gt
8 8
eg \

RESERVOIR

Figure 8. - Plan North Keystone mine, Copperopolis, Calaveras County.



Hole CH-2 (Cont'd.)

Footage Percent

From Zo gore. recovery scriptioy

531 576 48 Silicified, light-green, amphibolite-scattered
veinlets of white quartz, tiny masses of
green chlorite, scattered disseminated
pyrite.

576 601 89 As above, with occasional zones of pale-green
porphyry; the phenocrysts are irregularly.
bounded and are greenish-white in color};
aphanitic groundmss.

601 634 60 Pale-green, silicified amphibolite cut by
scattered veinlets of white quartz.

634° 646 93 Light-green, silicified amphibolite with

seattered veinlets of white quartz and
zones of porphyry.

646 651 100 Pale-green porphyry - cream, irregular,
bounded phenocrysts and aphanitic matrix,
more or less silicified. :

651 667 56 Silicified pale-green amphibolite with

scattered quartz segregations.

667 706 hg , Silicified pale-green amphibolite cut by
scattered veinlets of white quartz.

706 726 55 Light-green silicified amphibolite.

726 Bl 28 Light-green silicified amphibolite - pyritized

black argillite, at 730 feet, also small
zones of green porphyry - cream, irregular,
bounded phenocrysts in a aphanitic

groundmass .
731 753 37 Light-green silicified amphibolite.
7153 763 59 Green, silicified, amphibolite schist.
763 780 38 Silicified pale-green amphibolite - scattered
white quartz veinlets.
780 800 56 Silicified pale-green amphibolite, some quartz
' veinlets - minor amount of pyrite at 787
feet.
Hole CH-3
Location: WN. 369, 2039 E. Bearing: S. 70° W.
Elevation’ of collar: Level with collar Dip: -60°
of Hobo shaft. BX: 7-30 ft.
Depth: 519 feet. AXs 30-519 ft.
. NX: (O-7 ft.
Footage Percent
From pie gore recovery Description
° 32 46 Surface altered amphibolite, few quartz
veinlets.

4033 -37-


Hole CH-3 (Cont'd.)

Footage Percent
From Do core recovery Description
4o1 514.5 86 Green amphibolite schist somewhat chloritized,
occasional quartz veinlets and segregations.
5.5 519 718 Pale-green amphibolite schist with few quartz
veinlets.
Hole CH-4
Location: 1905 N., 465 BE. Bearing: S. 53° W.
Elevation of collar: 34.5 ft. below collar Dips -45°
of Jackass shaft. BX: 7-10 ft.
Depth: 315 feet. AX; 10-315 ft.
WX:. O-7 ft.
Footage Percent
Erom Do core recovery Description

lo) 16 al Surface altered amphibolite.

16 19 20 Approximate limit of surface alteration.

19 ek yd Light pale-green, silicified amphibolite.

ak 26.5 48 Iron-stained amphibolite.

26.5 ah 72 Iron-stained, silicified porphyry of aphanitic
groundmass and irregular bounded, cream-
colored phenocrysts to 33 feet; silicified
porphyry as above to 40 feet, balance black
argillite with thin scaley pyrite om
fracture plances.

AL ho 61 Light bluish-gray, silicified amphibolite
with thin scaley pyrite on planes that
fracture.

ho 59.5 65 Above 51 feet light bluish-gray, silicified
amphibolite with thin scaley pyrite on
planes that fracture. Below 51 feet, green
silicified amphibolite.

59.5 78 80 Light bluish-gray, highly silicified amphi-
bolite; thin scaley pyrite on fracture
planes.

78 80 88 Light-green silicified porphyry; green

aphanitic matrix, cream-collored, irregular,
bounded phenocrysts.

80 6 71 Light bluish-gray, highly silicified amphi-
bolite; scattered thin, scaley pyrite on
fracture planes.

96 98 87 Dark to black argillite.
98 100 ~ 87 Light-gray, highly silicified amphibolite.
100 iol 87 Argillite and quartz.
1ol 115 - ob Light-gray, highly silicified amphibolite
with minor amounts of pyrite.
115 118 98 Argillite with thin seams of fine pyrite.
118 120 79 Light-gray silicified amphibolite with scaley
pyrite.
120 125 79 Argillite with occasional thin seams of pyrite.

4033 - 39-


Footage
From To
125 128
128 137-7
137.7 140.5
140.5 141.5
141.5 1h9
149 150.5
150-5 155.7
155.7 170.5
170.5 189.5
189.5 212
212 216
216 226
226 234
234 237
237 243 .9
243.9  2h7.7
247.7 251.2
251.2 265
265 281.5
281.5 284.5
284.5 315

4033

Hole CH-4 (Cont'd.)

Percent
gore recovery
79
oT

7
TT
100

96
96

Te
i)

95
42

95

78
83

oT
80

70

87
67

Description

Bluish-gray highly silicified amphibolite.
Pale-green silicified amphibolite, scattered
intervals of argillaceous material, with

little quartz and scattered pyrite.

Light-colored siliceous material; pyritized.

Mineralized argillite.

Siliceous, mineralized material and argillite,
with thin seams of pyrite.

Argillite with fine seams of pyrite.

Silicified amphibolite and light-colored
siliceous material both carrying sulfides.

Pale-green silicified amphibolite with
sulfides.

Pale-green amphibolite with sulfides,
intervals of pale-green porphyry; cream-
colored, irregular, bounded phenocrysts in’
an aphinitic groundmass.

Pale-green silicified amphibolite with specks
of sulfides.

Silicified pale-green amphibolite, some
porphyry, minor disseminated sulfides.

Pale-green amphibolite with specks of pyrite,
gray siliceous material with sulfides
(iron and zinc).

Pale-green amphibolite with intervals of
porphyry, very little sulfides.

Gray siliceous material banded with sulfides.

Pale-green amphibolite, some porphyry,
specks of pyrite.

Pale-green amphibolite and heavy sulfides.

Pale-green amphibolite with specks of pyrite.

Light bluish-gray, highly silicified amphi-
bolite; pyrite as thin scales and in tiny
seams.

Light bluish-gray, highly silicified amphi-
bolite, minor amounts of pyrite is seams
and scales.

Gray, silicified amphibolite with sulfides
of iron and zinc.

Pale-green, silicified amphibolite, scattered
scaley pyrite.

- ho -


690 feet. During recent operations the upper portion of one of the old shafts
was utilized for ventilation from the 375-foot level of the main shaft. Four
levels’ with more than 3,000 feet of development had been driven from this
shaft. From July 1943 to January 1944, the main shaft was sunk to a depth of
1,115 feet below the collar. A crosscut on the 875-foot level was driven
eastward 270 feet. * Drifting tothe north from. this..crosscut aggregated 260
feet, whereas to the south the drifts extended more than 400 feet. Two stopes
were opened to the south of the crosscut by shrinkage. Mining widths in these
stopes average about 17 feet. Because of the chloritization of vein mterial
as well as of the hanging wall, many pillars left in stopes have failed. As
caving from the hanging wall and the consequent dilution exceeded the amounts
anticipated, cut and fill mining was being considered. Ore at the rate of 270
tons per day was hauled in 18-ton Diesel trucks to the Mountain King mill,
6-1/2 miles distant. :

Milling

After being crushed, the ore is ground in ball mills in two stages and
floated. Initial grinding is 100 percent through 48-mesh, whereas the
secondary stage is 100 percent through 80-mesh. Concentrate averaging 26 to
28 percent copper was obtained from ore containing 1.25 to 3 percent copper,
recovery being 95 percent. During 1943, additions to the mill increased its
capacity to 550 tons, the estimated daily mine production. As mine production
has averaged 250 to 350 tons, the mill did not operate on a 2h-hour schedule.
Following is the production record from Juhe 30, 1942, to June 30, 1945:12/

i Ore milled,/Copper content,} Average grade,

Period 4 tons _pounds i percent copper
June 30, 1942, to July 1, 1943 ..../ 40,832 2,187,913 | 2.68
July 1, 1943, to Dec. 31, 1943 ...../ 42,380 2,377,892 2.81
Jan. 1, 1944, to June 30, 1944 ..../ 51,110 2,198,716 2.15
July 1, 1944, to Dec. 31, 194b ....) 47, 45h 1,637,984 | 1.72
Jan. 1, 1945, to June 30, 1945 Y .., 42 001 1.627000 _| 1.91
Total scececscerececssesecssse! ae 10 00% 505 2.23

i/ Estimated.

Development and Milling Costs
Shaft-Sinking Costs

Size: Approximately 7 by 17 feet, or an area of 120 square feet.
Total footage: Includes stations and pockets figures at 120 cubic feet as 1

foot of shaft.

L/ Otto, Schiffner, (deceased), general manager, Keystone Copper.

4033 - lo-


Hole K-2 (Cont'd.)

Analyses
Foota; Size of Core i Sludge
From: Tos | Feet core Cu, percent | Au, oz. | Ag, oz. | Cu, percent _! AU, oZ. ji Ag, oz.
593.1 | 603.2 | 10.1 EX | 0.05 | H
613.4 | 618.5 | 5.1 EX | 12 | |
618.5 | 60.0 | 145 EX | | 61 |
617.7 | 619.5 | 1.8 EX 0 «43 | ! |
619.5 | 620.5 | 1.0 EX | | +79 | \
620.0 | 625.4 1 5.4 EX | | +10
625.4 | 631.9 | 6.5 EX | Olt |
640.0 | 6ho.2 | 2 EX 437 | | | |
635.04 645.4 | 10.0 EX | i 10 | i
Hole: K-=3 Depth: 571 feet.
Location: 1966 N.; 394.5 EB. Dip: -72°
Elevation of collar: 1,018 Bearing: S. 47° 30' wW.
Analyses
Footage Size of Core A Sludge
From: Toz_| Feet _ Core Cu, percent i Au, 62. Ag, oz. Cu, percent | Aus oZ. |
90 6 92.3 | 1.7 BK 0.09 : .
2.3 9h 0 1.7 BX 10 _
312.0 318.5 6.5 AX “12 i i/ 1/
313.8 | 314.0 2 AX +23
312.0 320.0 8.0 AX 0.09
320.0 | 321.3 | 1.3 AX 1
323.0 | 323.5 5 AX Ag i i
320.0 323.0 3.0 AX 18
323.5 325.4 1.9 AX 07
323.0 | 334.5 | 11. AX 225
334.6 | 337.0 | 2. AX +05
337.0 | 337.2 2 AX 12
337.2 338.7 1.5 AX -B
é5.1 | h66.7 | 1.6 EX | 432
4.66.7 468.0 1.3 EX i 0 Trace None |
468.0 | 869.5 | 21.5 EX fo oa | |

i/ less then 0.2 foot at 313.8 feet.
4033 - 50 -


INTRODUCTION AND SUMMARY

As a result of the examination of many copper-zinc properties in the
West Belt area of California, nine were chosen for exploration projects by
the Bureau of Mines. This was part of the Bureau's wartime mineral-
development program aimed at maintaining production of essential metals and
increasing ore reserves.

The properties explored were the El Dorado, El Dorado County; Copper
Hill, Newton, and Gray House, Amador County; Constellation, North Keystone,
and Collier, Calaveras County; and American Eagle and Akoz, Mariposa County.

In addition to surface sampling and mapping, 41 holes, aggregating
18,134 linear feet, were diamond-drilled. Detailed results of the work done
on all properties except the El Dorado and Akoz are given in this report.
The El Dorado and Akoz were discussed in Reports of Investigations 3896 and
inh, respectively. Figure 1 is an index map showing the location of the
mines covered in this publication.

In this report, the general features of the West Belt are summarized,
and mineral composition, characteristic types, and modes of occurrences of
ore deposits are described. The work performed by the Bureau of Mines is
reported in separate sections under the names of seven mines; each mine is
described separately, with a concluding section covering the work performed
by the Bureau of Mines.

Development and milling costs are reported in detail for the Keystone
mine. The Appendix embraces diamond drill-hole logs for the Newton, Copper
Hill, Gray House, and Constellation mines and contains other pertinent
information of drill holes, samples, and analyses of samples. Analyses of
drill-hole samples are shown in figures 3, 5, 6, 9, 11, and 13.

ACENOWLEDGMUNTS

Special acknowledgment is made to George Heyl of the Federal Geological
Survey, for his aid on many of the geologic problems. A. C. Rice, of the
Reno Rare and Precious Metals Experiment Station, Metallurgical Branch,
supervised the analytical work.

The Bureau is indebted to the late Otto Schiffmer, general manager of
the Keystone Corp., for furnishing detailed cost data at the North Keystone
during the difficult war years of 1943 and 1944.

GENERAL FEATURES
. .-The West Belt. coppex-zinc- bearing -zone- traverses: the western slope of the
Sierra Nevada with unusual persistente from Butte Courity to Kern County, a
distance of more than 300 miles. It ranks among the important producing areas

4033 -1-


Collier mine..

CONTENTS (Cont'd.)

Introduction
History.......

Physical features and communications.. se eeeeeeeeeeeeee 13
Description of the OF€...cssecsccecssecececececeveseseses 13
Work performed by Bureau of Mines. . 1h
American Eagle mine........eee0e . 14
Introduction. ...ssseeeeees . 14
History and ownership.....cscceseeeee eevee Wy
Location, physical features, and communications 15
Ore depositS......cseeeeee . 15
Work performed by Bureau of Mines. . 16
APPCNdIX.. cece ccc cree cccccecrecscenes 17
ILLUSTRATIONS
Follows
Fig. page
1. Index map of some West Belt zinc-copper mines,
California..... ween eee eens oe 2
2. Drill-hole locations and underground workings, Newton
mine, Amador County, Calif. .e.ceeceeeccceceeceeveee 4
3. Vertical section, looking northwest, showing drill
holes 2, 3, and 5, Newton mine, Amador County, Calif. 4
4, Plan sketch showing diamond-drill holes Cl, 2, 3, 4,
and 5 and part of underground workings, Copper Hill
mine, Amador County.....cccccccceserececevecseevvses 6
5. Section through drill hole CH 2, Copper Hill mine,
Amador County.. seeeeees 6
6. Section through dr: ole » Copper Hill mine,
Amador County. .ccsccsccsecccescsccccsccecvsevceseees 6
7. Underground workings and diamond-drill hole C 1,
Constellation mine, Calaveras County........eeeeeeee 6
8. Plan of North Keystone mine, Copperopolis, Calaveras
COUNTY. cee cece cece cece eee een eee e eee ee reese esses esees 12
9. Sections of North Keystone mine, Copperopolis,
Calaveras County... .seseeeees sees 12
10. Collier mine, Calaveras County.. we eeee 14
1l. Vertical cross section through drill holes, Collier
mine, Calaveras Countys..cccssecceseeceeeenes . 14
12, Plan of American Eagle claim, Mariposa County.. 14
13. Vertical sections, American Eagle claim, Mariposa
County..eeeeeee tenes 16

4033

- ii -


t 2 3
SCALE INFEET

Figure 4. - Plan sketch showing dianond-drill holes CH |, 2, 3, 4, and 5 and part of underground
workings, Copper Hill mine, Amador County.


i) 10
La
Scale in Miles

MARIPOSA

Worner QCOULTERVILLE

ee
Owens By
Reservoir
=
=a

iY xchequer Dom

mericaneogle Mine
|ERCE DF wh

i

MERCED

CEGRAND TM. _/”
Seaanow®

Figure I. - Index map of some West Belt zinc-copper mines, Cali fornia.


American Eagle Mine (Cont'd.)

Hole: AE-2 Depth: 4k6 ft.
Iocations 1911 N.; 1225 W. | Dip: -52°
Elevation of collars; 1,331 ft. Bearing: S. 66° W.
| : Analyses
Footage [Size of Core i Sludge

Front rape eet | cone Cu, percent ins percent {Aus oz.! Ag, 0Z.' Cu, percent'Zn, percent: Au, oz. iAg, oz.

: 7.5 3. } ¥0 0; i on Trace , None '
ong [252.616] ax 03 | el oj” « |
252.6 [257.2 | 4.6 | ax 202 * “ " /
258 1361.8 | 3.8 AX * 02 el oF om foe |
263 267.2 | 4.2 AX % 02 #1 | “ |
267.2 1271.2 | h.o AX 02 | #21 " [ * i
363.5 1364.7 | 1.2 Ax 3 | 3.8 "oy oy i |
364.7 1366.2 | 1.5 | ax 6 | Ce \ |
366.2 [367.7 | 1.5 | ak 103 *1 | # " |
33 368 [83 AX 7 0.05 0.7 Trace None
6 370: 2.0 AX -0 *1 "
"370 |370.95} .95| AX 02 *.1 “ *
370.5 1375 45 Ax 17 ok " "
370.95|372.1 | 1.15] AX oho 5.8 * "
372.1 |373.8 | 1.7 AX +605 2.2 .
373-8 [374.4 | 6 | ak 002} KL " | |

4033. - 59 -


Hole K-4 (Cont 'd.)

Analyses

Footage Size of Core ! Sludge
From: To: Feet core Cu, percent. Au, OZ. Ag, oz. , Cu, percent Au, oZ. Ag, oz.
652.5 | 653.5 | 1.0 EX ! \ ; 0.07 |
653.5 | 656.6 | 3.1 EX | i 02
653-5 | 659.8 | 6.3 EX 0.02 |
656.0 | 660.7 | 4.7 EX | ' +05
6614 | 62.6112 | EX 03 | |
660.7 | 663.2 | 2.5 EX | | ell | -
697.0 | 706.9 | 949 EX | | 04
735.6 | 743.9 | 8.3 EX | | to1
743.9 | 750.7 | 6.8 EX | 205
750 7 756.0 | 5.3 EX | 206
752.45 | 753.55! 1.1 EX 006
756.0 | 761.2 | 5.2 EX | 49
761.2 T1005 | 9-3 EX 1 09
781.0 791.0 |10.0 EX | 32
791.0 } 801.6 |10.6 EX | 08 a
801.6 | 813.0 |12.4 EX |- el aa
813.0 | 823.0 |10.0 EX -08 |
823.0 | 833.0 [10.0 EX _ 206 i
4.033 - 52 -


Collier Mine (Cont'd.)

Hole: C-3 Depth: 336 ft.
Locations: 790.7 N.; 402.8 W. Dip: -70'
Elevation of collar: 1000.8 Bearing: S. 45° We
Core size: NX: 0-14 ft.;
BK: 14-38 ft.;
AX: 38-356 ft.
Analyses
Core Sludge Adjusted Average
Percent Cu,{ Zn, Cu,; Zn, i Cu, | Zn,! :
Pootane core Per- |Per- Per- |Per- | | Per- |Per-
! record | cent icent |Au, 02.|Ag, oz.| cent}cent|Au, 0o2.'Ag, 02.! cent cent Aus OZ Ag, 02.
1
314 | 319 5 100 AX | 0.21] 2.8] Trace | None |0.10| 2.8! Trace 0.16] 2.8! Trace | None
319 322. 3 -100-- | AX 17] 2.4 " " |
322 324 2 100 AX 215 | 1.7] 0.005 | 0.25 015) 204 . +15] 2.2) 0.005 | 0.15
32h 327 3 100 AX 032) 1.1 005 225
327 | 328 1 100 | AX | «84} 9.2 | Trace | None 12; 1.8) * 784] 9.2] Trace | None
328 | 330 2 99 | AX | 407] 1.1] * *
330 | 333 3 9 AX F 09) 1.9 “ 0.20 307 2.8 * <091 2.2 * 0.20
333/338 =| 5 loo | AK | 417/23) " | None | 415) 2.7) * 16] 2.5] " | None
338 339.5] 1.5 100 AX ol9| 1.7 * " j
339-5 | 343 3.5 100 | Ax 2211 |
4033 - 55 -


D.D. Hole C-I
Dip -45°

AIN SHAFT (400 Vertical)

200 FEET

Figure 7. - Underground workings and diamond-drill hole C-1, Constellation mine, Galaveras County.


Bureau of Mines
Report of Investigations 4760

INVESTIGATION OF WEST BELT COPPER-ZINC MINES
EL DORADO, AMADOR, CALAVERAS,
AND MARIPOSA COUNTIES, CALIF.

By FRANK J. WIEBELT, W. C. SANBORN, R. R. TRENGOVE,
AND SPANGLER RICKER

United States Department of the Interior — February 1951

| metadc38555


Hole Nos
Locations

ook

821.3 N.; 581.3 W.

Elevation of collar: 1015.8

Collier Mine (Cont'd.)

Depth: 291
Dip: -70°

Bearing: S. 45° We

Core sizes 3 O-Lk Pte;
BK: 14-32 ft.;
AX: 32-4 ft.;
EX: 4-291 ft.
Analyses : mo
L Sludge Adjusted Average
Percent | Size; Cu, i Zn, Cu,; Zn, Cu,; Zn,
Footage core | of | Per- Per- Per-| Per- | Per-i Per-
From! To: | record | core! cent Au,o2. Az, oz. | cent centjAu, oz, cent! cent|Au, of. JAZ, OZ.
1 | 7
i |
261 266 | lo | EX 0.02! 0.2} Trace -| - - -
266 268 | 33 | EX he cn a -| - - -
268 272 100 | EX | 0.06/04
205} 1.4 Oh 3| * 0.05! 0.5! Trace | None
272 277 83 EX 34 | 4.3 |
Oh} 2.1 209) 1.8 " 212) 2.3 " "
277 281 85 | EX 209 | 1.9
252 | 2.4 “17 11 " 20) 1k)” "
281 286 100 | -EX Oh | " - - - -

4033




At the time of the Bureau of Mines exploration, the property was under
lease from its present owers, F. Defrene ond his sister, to J. H. lester of
Jackson, Calif. Iater, it was taken over by the Bradley Mining Corp., under
whose management 55,000 tons of ore yielding more than 6,500,000 pounds of
copper was produced 3

Geology and Mine Workings

The deposit is in a belt of amphibolite schist lying west of the Mother
Lode and traversing the district in a northwesterly direction from the
Mokelume to the Cosumes Rivers. The gossan-capped vein strikes west of
north and dips approximtely 70° east. Mineralization consists principally
of chalcopyrite and pyrite and occurs as a massive lenticular ore body fora
length of over 300 feet, as exposed on the 7th level. The vertical range has
been proved, by drilling, to extend more than 800 feet along the dip. It
ranges in width from a narrow seam to 6-1/2 feet.

The mine workings at the time of the project consisted of a 400-foot,
inclined, 1-1/2-compartment shaft, 7 levels, and a number of winzes. The
inclination of the shaft averaged 70°. Drifting, as indicated by old mine
maps, totaled more than 2,000 feet. Both hanging and foot walls are firm,
and very little timber is required in mining. A second shaft, 150 feet deep,
is on higher ground 300 feet southeast from the main shaft but it is now
caved and inaccéssible.

Since the Bureau of Mines drilling was completed, the 400-foot incline
has been sunk to the 775-foot level, from which a winze was sunk 143 feet.
A great portion of the recent production came from the new workings between
the o0- and 775-foot levels.

Work Performed by the Bureau_of Mines

Five diamond-drill holes, ranging in length from 700 to 1,076 feet, were
drilled. One drill operated two to three shifts per day 6 days por week.
Contract drilling aggregated 4,258 feet and consisted of 50 fect of "NK"
holes, 80 feet of "BX" hole, and 4,128 feet of "AX" hole. A total of 230 feet
of casing was set. Core recovery from the 4,258 feet drilled totaled 3,068
Peet, or 72 percent. From the 5 holes drilled, 29 samples, consisting of 19
core and 10 sludge, were taken for analysis. Holes 2, 3, and 5 encountered a
downward extension of the vein. All of the holes had a marked tendency to
become normal to the schistosity and were surveyed for dip et 100-foot
intervals.

~ The holes were all in schists, and the ore zone was well-defined. The
location, cross sections, and assays are shown on figure 2 and 3, and
additional data are to be found in the appendix.

87 P. R. Bradley Jr., San Frencisco, Calif.

4033 -4e


developed to comparatively shallow depths, but the Union and Penn mines have
been productive to depths of 1,800 and 2,800 feet, respectively.

Prices of the metals have influenced the cut-off grade of ore mined.
During the World War II, the average grade of copper ore mined at the North
Keystone was about 2.25 percent copper ,4/ whereas the ore reserves at the
Blue Moon averaged 14 percent zinc and carried small amounts of gold, silver,
and copper .5/ Ore reserves at the Penn mine before recent operations were
reported to contain 3.96 percent copper, 9.36 percent zinc, 0.068 ounce gold,
and 2.76 ounces silver .6/ The accompaning drill logs show the type of ore
at the Newton and Copper Hill deposits.

Ore bodies are generally marked on the surface by an easily recognized
gassan, and the oxidization extends from a few feet to around 75 feet in depth.

NEWTON MINE
Introduction

The Newton is in secs. 28 and 33, T. 6 N., R. 10 E., Mount Diablo base
line and meridian, in the central part of the mi/h of the Jackson
Quadrangle, Amador County, Calif. It can be reached by following Highway 88
northwest from Jackson for 7 miles or by following the same highway southeast
from Ione for 4 miles.

The nearest railroad shipping point is Ione, Calif., a small town witha
population of 1,000, situated on a branch line of the Southern Pacific
Railroad.

The area in the vicinity of the mine is drained by Mountain Spring Creek,
@ northwesterly flowing feeder of Sutter Creek, which is a tributary of the
Cosumes River.

HISTORY

This was one of the first copper mines to be operated in California. It
was opened in the early sixties and was worked vigorously before 1866, In
1887 it was reopened by the Newton Copper Co. and has been worked intermittently
ever since. An 80-ton smelter was erected in 1889, and in 1891 leaching was
done to recover cement copper. During 1900, 3,500 tons of 7-percent ore was
mined and heap-roasted, after which 3,000 tons was smelted to make a 50-percent
matte. The estimated ore production of this property up to date of recent
operations was 33,000 tons, two-thirds of which had been beneficiated on the
property .7/

U7 Schiffner, Otto (deceased), Manager, Keystone Copper Corp.
/ J.H. A. Williams, New York City.
6/ Juhlihn, C. E., and Horton, F. W., Mineral Industries Survey of The United
States. Part I - Calaveras Co., Calif.: U.S. Bureau of Mines Bull.
433, 1938, p. 115.
au Copper Resources of Californias State Division of Mines, Bull. 50, 1908,
pp. 223-224,

4033 -3-


Hole N-5 (Cont'd.)

Footage Percent
Erom To core recovery Description
lol 115 oh Pale-green amphibolite schist, few quartz

stringers, disseminations of epidote
throughout, somewhat chloritized.

115 Vh6 719 Pale-green amphibolite schist, few quartz
veinlets, disseminations of epidote
throughout, scattering of pyrite, all
somewhat chloritized.

16 ws] 56 Green chlorite schist, considerably pyritized.

17 166 58 Green chlorite schist, some intervals heavily
pyritized, some disseminations and veinlets
of epidote.

166 180.5 41 Green chlorite schist, some pyrite at 172
féet, few seams of epidote, some seams of
hematite.

180.5 183 80 Quartz breccia.

183 221 719 Green chlorite schist, much epidote dissem-

inations and some epidote veinlets, tiny
hematite seams.

221 231 96 Pale-green amphibolite schist, much quartz,
epidote in veinlets and masses, interval
silicified. .

231 ehh oT Green amphibolite schist, considerable

epidote disseminations and veinlets, much
lavender banding due to hematite.

ahk 259 81 Green amphibolite schist, considerably
chloritized little epidote and quartz in
small veinlets.

259 289 96 Pale-green amphibolite schist, some chloriti-
zation on planes of schistosity, few small
white quartz veinlets.

289 300 99 Pale-green amphibolite schist, much epidote
disseminations, considerable chloritization.

300 305 95 Dark-green chloritic schist, veinlets of
epidote.

305 34k 65 Dark-green amphibolite schist considerably

chloritized, few veinlets of quartz and
epidote, some scattering of pyrite.

34h kok 80 Pale-green, silicified, amphibolite schist,
some epidote disseminations, few veinlets
of quartz and epidote.

kok 42 100 Green amphibolite schist, mich epidote
disseminations, some quartz veinlets and
masses associated with epidote.

ki Lo 70 Green amphibolite schist, considerably
chloritized, interval highly banded with
tiny hematite seams, few intervals show
epidote veinlets.

4033 ~ 29 -




Drill Hole Data

Collier Mine

| Elevation j
\_ Coordinates of Depth, |
Hole NV i W collar, ft.j feet Dip Bearing Size_of core
q .
C-1 .ee0.! 163.9 | 238.1} 966.11 350 | -70°| S.55° w. Wi 0-22 ft.; BK: 22-29 ft.; AK: 29-350 ft.
C-2 weve. | 246 178.5, 969.4 358 | -70°| S.55° W. s O-k ft.; BXs 4-21 ft.; AX: 21-48 ft.;
EX: 48-358 ft.
C+3 2-22] 790-7 | 402.8] 1000.8 356 | -70° | s.45° w. MX: 0-J4-ft.; BX: 14-38 ft.; AX: 38-356 ft.
C-k ..e0-| 821.3 | 581.3] 1015.8 291 | -70° | S.45° we NX: 0-14 ft.; BX: 14-32 ft.; AKs 32-hh ft.;
EX; 44-291 ft.

4033 - 53 -


i121 costs for 6 months ended Dec. 31,1943:

Tonnage milled: 42,380 tons dry ore

Account Total cost Cost per ton

LADOF sececececececccececeseeeceensseteenene ] $38,767-4 $0 .821
Compensation insurance 2,122.28 2050
Payroll taxes i 1,520.26 i 0036
SupPlicS vscccscceecesscecceessessecesseesees | 20,760.73 | +490
Transportation, engineering, drafting, |

supervision, office, CtC. sessccssocsvesers, _ 187.32 004
Truck and safety expense : 656.21 | 2016
Group insurance 333 .65. 008
Equipment rental 1,878 .00 Ohh
POWEL seceecvoevevores 9,582.51 2226
Ore haul to Mill .ecccsvevccsrcnncesscwsecsce 13,768.16 325
Rental charges on mill .cccseceserccaccsccens 14,833.11 350
Assay expense | 1,278 64 030

Total woecessencocciecereceroedivsseeees | 101,708.28 2.40

Work Performed by Bureau of Mines

Diamond drilling by the Bureau in March 1943 and subsequent drilling
undertaken in August and continuing until December 2, 1943, explored @ block
of ground immediately north of the mine workings for a lateral extent of 800
feet and to a depth of 700 feet. Four holes totaling 2,642.5 linear feet
were drilled. The location and cross sections of holes with assays are shown
on figures 8 and 9. The assays are adjusted averages from core and sludge
samples. Additional data are listed in the appendix.

Hole K-1 was drilled to intersect the downward projection of an: attractive
gossan outcrop. K-2 to K-4 were drilled to ascertain the attitude of the ore
intersection of K-1 in depth. Hole K-3 explored the area under siliceous
gossan to the north.

COLLIER MINE

‘Introduction

In May 1943 the lessee of the Collier requested the assistance of the
Bureau of Mines in developing additional ore reserves so that production
might be maintained after the ore then in sight would be depleted. A drilling
project was started in July 1944 and concluded in September of the same year.
Four holes aggregating 1,355 feet were diamond-drilled.

History

The property was first operated in the 1860's, when there was a small
production from the oxidized gold ores of the outcrops. In 1917, a pocket of
gold ore was discovered in a shallow shaft. After this pocket was mined, the

4033 > 12


Record of diamond drill-hole values

Newton mine

Hole: N-2 Depth: 800 feet.
Location: 429 N., 865 BE. Dip: -76°
Elevation of collar: 31 ft. above collar of main shaft. Bearing: S. 67° 45' w.

Core sizez MX, 0-15 ft.; BX, 15-40 ft.; AX, 40-800 ft.

[Percent / Size Analyses
Footage core of Core =~ ju Sludge
Fromg To: Feet rec. _, core | Percent Cu ‘Percent Zn] 0z. Au | 0z. Ag j Percent Cu | Percent 2n ]oz. Au [oz. Ag
] i i H y
568.9 (569.5 | 0.6 AX 4.85 fo.. | Trace 0.30 | |
569.5 {571 5 | AX 1630 | ol " 20} 3.08 | ok Trace | 0.40
571 571.3 3 | AX +50 6 "| 20]
T 4 | ‘ 210 6 " +10
571.3 [573 1.7 AX 205 3 a ~rreeO oj.
5 (575.3. | 2.3 | Ax or | 10 "| none] i .
, 5 . None
575.3 [578 2.7 | ax a! 3 " | | |
578 519 1.0 AX +23 | 3 ” | o%10| |
579 |580.4 | ad AX 37 | 6 " | None |
580.4 (581.3 | 29 | AX | 21 | 5 “1 0.10 +23 oA * 0-10
581.3 [583 Le7 | AR | dO Ue2 " ' None |
i i H

i/ Less than.

4033 -17-


Footage sunk: 597.3 feet (began in July 1943 and completed in January 1944) .

Material penetrated: Principally spotted schist and greenstone.

Account Total cost. Cost per foot
Labor sesecoevcevcvececeses | $46,701.89 $78 .188
Compensation insurances . . | 2 38 33 3 es
Payroll taxeS sesseeces ° 1 AB 2.659
Supplies seccceccsscssecoces ee 177289. 28 .9h6
Explosives 2 ;4h1.04 4.087
Lumber sececeseecceccrecncccesenscoe | 1,722.48 | 2 884
Transportation, drafting,.. I
“supervision, office, etc. veverses: |: 222 he 373
Truck expense and safety eteene | *90.00 0151
Group insurance . ebecee | 211 8 Sh
POWEL cececcecececeene eooe Th 2,3835 3-990
Equipment rental ... eee "11.40 2019
Total se. es | "'75,071.03 125.682
Costs of drifts, crosscuts, and raises for 6 months period ended Dec. 31, 1943:
— Sor feet of drifts and crosscuts T310 Foot of raises
Account, |Total cost | Cost per foot Total cost |Cost per foot
Tabor sesseeeseeeee|  $6,787-42...4.  7.567-- | $12,820.68 9.790
Campensation- , 4 . . :

_ insurance . a 343 653° +} «383° 660 26 504
Payroll tAXES seeee 229.02 | 255 4.52 .20 345
Supplies ersseseees 2,091.25 j 2.331 2,858.21 2.182
Explosives seseeces 1,735.62 ! 1.935, 1,779 02 1.358
Lumber ceeaceceseces 89.77 | +100 962 .82 +735
Truck and safety 6 |

@XPENSE eeecesecs 3 032 071 138.90 2106
Equipment rental .. 503 «10 | 2561 523.11 1399
Group insurance ...| M9 1k | 2088 110.61 2084
POWED ceocncecocere 378.15 | 422 688 £54 2526
Transportation, |

engineering, |

drafting, super- |

vision, office, | .

CLC. eeeeee oe | : : 108 .60 083

Total erecesee! 12,300.32 i 23.713. 21,102.95 16.112

Total drifting and crosscutting: For l-year period ended June 30, 1944, 2,278
feet costing $32,165.52 for an average of
$14.12 per foot.

Total raising: For l-year period ended June 30, 1944, 3,561 feet costing

$60 ,133 47 for an average.of $16.889 per foot.

4033 -nh-


Hole CH-2 (Cont'd.)

Footage Percent

From Zo core recovery Description

321 329.5 83 Light-green silicified amphibolite.

329.5 334.5 88 Pale-green porphyritic amphibolite with

. quartz veinlets.

334.5 339 _100 Silicified pale-green amphibolite with
quartz veinlets.

339 361 81 Silicified pale-green amphibolite.

361 419 66 Pole-green silicified amphibolite with
scattered tiny veinlets of white quartz
and small intervals of pile-green porphyry
with cream-color irregular, bounded
phenocrysts.

41g 46d 15 Pale-green silicificd amphibolite with
scattered white quartz veinlets and small
areas of porphyry.

46h Lh 86 Silicified amphibolite with white quartz
veinlets.

Ah 496 85 Silicified uralite schist with veinlets and

small lenses of white quartz and chlorite-
epidote occurs in voinlets and disseminated
a very minor amount of pyrite is dissemi-
nated throughout with a slight increase at
49k feet; few tiny veinlets of calcite are
also present, but in goncral it is lacking.

406 510.2 48 Silicified porphyritic schist with chlorite
phenocrysts; considerable amount of pyrite,
both in large cubes and disseminations;
large of epidote disseminated and in vein-
lets.

510.2 510.5 100 3 inches of silicified rock with irregular
masses of tremolite ond chlorite and a
considerable amount of massive chalcopyrite

510.5 516 yh Silicified rock containing irregular masses
of tremolite and chlorite and considerable
disseminated pyrite 510.5 to 512 feet.
Balance porphyry with phenocrysts altered
to chlorite, contains short veinlets of
chlorite-uralite in groundmass, and some
tremolite is present; a considerable amount
of disseminated pyrite. .

516 521 100 Silicified graywacke containing sm21l masses
of chlorite and some disseminated epidote,
a few calcite veinlets - some tremolite -
pyrite is disseminated throughout this
interval in mederate amount»

521 531 5h Uralite schist-silicified in some zones, 1

: inch milky quartz veinlet at 525 feet,
small masses and veinlets of chlorite, one
small veinlet of calcite-a moderate amount
of disseminated pyrite.

4033 - 36 -


of copper-zinc ores in California. From the discovery of the Napoleon mine

in 1860, there followed, in rapid succession, discovery of many of the typical
mines such as the Union, Quail Hill, Collier, Keystone, Newton, and Campo
Seco.

Reports of the State Division of Mines state that the first few years’
production came from selected high-grade ores that were shipped from San
Francisco to England or the Eastern States. By 1868, the "Mineral Resources
of the United States west of the Rocky Mountains" reported seven noteworthy
smelting plants for the reduction of copper ore in or adjacent to the West
Belt area. Not until 1900 did the annual copper production reach appreciable
amounts, and not until the recent world war did zinc production reach a
creditable figure. From 1894. through 19h6, the recorded copper and zinc
production from Butte through to Kern County totals more than 200,000,000
pounds and 50,000,000 pounds, resyectively.3/

Although the area contained such important past producers as the Penn
mine, Union, and.others, a great part of the production in recent years
depended largely on premium metal prices for economical operations. The Penn
and Newton were the only active mines during 1947.

The West Belt shows the characteristics typical of the western flanks of
the Sierra Nevada at altitudes ranging from several hundred feet at the Penn
mine, Calaveras County, to several thousand feet at the Big Bend in Butte
County. Most properties are within easy access to good paved highways.
Climatic conditions are ideal for mining. Summers are hot and dry and winters
are moderate, with rainfall up to about 40 inches per year and at times som
snow.

ORE DEPOSITS

The ore in general occurs as sulfide replacements of highly sericitized
schists derived from various types of volcanics and intrusives. The principal
economic minerals are chalcopyrite, sphalerite, gold, and silver. The more
common associated minerals are pyrite, pyrrhotite, barite, bomite, calcite
and quartz.

Some of the ore bodies in such mines as the Penn are made up of a mixture
of both copper and zinc minerals in such proportions that both are of primary
economic importance.

At the Penn, the gold and silver content of the ores is also of appreciable
value. At other properties, such as the Union at Copperopolis and the Newton,
only the copper minerals are important. The Blue Moon, Big Bend, and others
have been worked primarily for their zinc content.

The ores as a rule consist of intimately mixed sulfides in, lenticular
masses ranging in width froma few feet to over 40 feet. In length, the ore
bodies range from a few feet to more than 500 feet and some of them have been
stoped to a depth of more than 1,200 feet. The mines as a whole have been

3/7 Copper in California: California Min. Bur. Bull. 144, 98, p. 15.

4033 -2-




Record of Diamond Drill-Hole Values

Holes C-1 Depth: 330 ft.
Location: 163.9 N.; 238.1 W. Dip: -70
Elevation of collar: 966.11 ft. Bearing: S. 55° W.

Core size: WX: 0-22 ft.;
BX: 22-29 ft.;
AX: 29-350 ft.

Percent | Size } Analyses
Footage core of Core aT Sludge
From: Tos Feet_| record] core | Cu, percent Zn, percent) Au, oz.j|Ag, 02.{ Cu, percent|Zn, percentiAu, 02.i/Ag, oz.
286 291 5 100 AX 0.05 Ol 0.005 | 1.05 | 0.05 OL 10.005 | 0.90
291 | 295 4 75 | Ax 05 ol .005 | 2.70 | Oh | 3 | 005 | 2.90
334 | 339 | 5 90 | AK 21 8 2005 | «25 | | |
339 | 3bh 5 22 | AX 208 3. Trace | None} t l |
Hole: C-2 Depth: 358 ft.
Location: 246 N.; 178.5 W. _ Dip: -70° o
Elevation of édllar: 969.4 ft. Bearing: S. 55 W.
Core size: WK: 0-4 ft.;
BX: 4-21 ft.;
AXs 21-48 ft.;
EX: 48-358 ft.
(Percent | Size : Analyses
Footage : core of ‘ Core ft Sludge
From: z_| Feet | record | core | Cu, percent) Zn, percent|Au, oz. |Ag, 0z.; Cu, percent j2n, percent Au, 02.)Ag, oz.
318 =| 323 | 5 25 EX ° ° 1 O15 Oy | Trace | 1.20
323. |328 | «5 23 (| EX i | 06. | Bo ptm 20
328 330 2 5 EX | «09 | el | " | +10
330 = | 333 3 78 EX \ +07 el ; ” | None
333 338 | 5 23 EX 15 | 3 | en]
338 iy 15 Laz EX | 1 a _

4033 > 5h -


Footage
From Do
245.5 27
2hy 289
289 295
295 302
302 320
320 347
347 355 |
355 357
357 370
370 405
405 462
462 4.90
490 502
502 510
4033

Hole N-4 (Cont'd)

Percent
core recovery Description
70 White quartz with little calcite, intercal-

ations of green amphibolite, minor pyrite
in disseminations and in masses.

é2 Green amphibolite schist, much dark-green
chlorite, tiny epidote veinlets, somewhat
chloritized, very few tiny veinlets of
quartz and calcite.

100 Light-green amphibolite schist, numerous tiny
epidote veinlets, some dark-green chlorite
as fillings.

86 Light-green amphibolite schist cut by tiny
calcite and quartz veinlets, scattered
pyrite, fractures filled with dark-green
chloride.

45 Brownish-green amphibolite, few milky calcite
veinlets, scattered cubes, and very minute
seams of pyrite.

55 Green amphibolite schist (uralite?), few
quartz and calcite veinlets, disseminations
and veinlets of epidote, few specks of fine
pyrite, somewhat silicified, generally

massive.

95 Green silicified amphibolite schist, veinlets
and disseminations of epidote, scattered
fine pyrite.

Th Browhish-red schist with green (chlorite?)
planes. .

91 Light-green amphibolite schist, scattered

veinlets of quartz and calcite, mch
epidote veinlets and disseminations.

80 Light-green amphibolite schist highly banded
by zones of lavender-colored schist, con-
siderable epidote in veinlets and dissem-
inations, all more or less chloritized on

; planes of schistosity, few calcite veinlets.
69° Light-green amphibolite schist, mach epidote
disseminations, few quartz veinlets, few
intervals have lavender banding (hematite?) ,
leached appearance.

48 Light~-green amphibolite schist, much epidote
disseminations, leached appearance,
somewhat chloritized.

83 Green amphibolite schist, considerable
disseminations of epidote, two l-inch white
quartz and calcite, quite massive.

AL Light gray-green, talcy, soft schist, highly
chloritized yet compact.

- 27 -


Hole K-3 (Cont'd.)

Analyses
Footage Size of Core i Sludge
Froms Tos Feet core Cu, percent. Au, 02. Ag, oz. Cu, percent Au, 02. Ag, OZ.
469.5 | 469.65) 0.15 EX 1.93
469.65} 470.35} .70 EX -38
465.1 475.1 110.0 EX 0.18 Trace 0.10
475.1 | 481.7 | 6.6 EX +09
475.1 484.2 | 9.2 EX 14
4h 3 501.9 | 7.6 EX OL 09
501.9 | 502.2 3 EX 1.88
502.2 | 503.2 | 1.0 EX -18
501.9 | 506.9 | 5.0 EX 36
506 «9 511.9 | 5.0 EX 08 el
511.9 | 521.5 | 9.6 EX 07
511.9 521.9 [10.0 EX 23
532.0. |. 540.6 | 8.6 EX +08 \
540.6 [ 5504 | 5.8] EX +09 | |
562.7 | 567.2 14.5 EX 01 | |
North Keystone Mine
Hole; K-4 Depth: 833 ft.
Location: 1863.5 .N.; 852 E. Dip: -75
Elevation of collar: 1,026 ft. Bearing: S. 46° w.
Analyses
Foota Size of Core iz Sludge

From: | To: | Feet. core Cu, percent | Au, oz. Ag, oz. | Cu, percent | Au, oZ. Ag, oZ-
435.0, | 435.3 | 03 AX 1.33 | i
645.0 650.0 5.0 EX | 0.09
647.5 | 47.95 | oh EX Bh |
647.95 | 68.7 | 75 EK 205 | |
750.0...) 651.2 | 1.2 EX +06 |
650.0 | 652.5 | 2.5 EX | | +05

|
4033 - 51-



Drill Hole Data

American Eagle Mine

ij j Elevation |
Coordinates | of Depth,
Hole Nc} W |collar, ft.| feet | Dip} Bearing | Size of core
AB-1 v.44 1786 | 1106 1331 426 | -ho® | s69°w O-10 ft.; BK: 10-112 ft.; As... 112-366 -ft.;
ae wpe ee freee 2 366-186 ft ;
"Iglt 11625 1331 WE | -52° 1 s66°w + 0-10 ft.; Bkr 10-191 ft.; AK: 191-446 ft.
AE-3) e004 1985 | 1245 1329 406 | -4o° | n89°W | MK: O-14 ft.; BK: 1-96 ft.; AK: 96-406 ft.
AB-4 .....11790 41104 1331 kge | -51° | 376° | NK: 0-20 ft.; Bk: 20-182.5 ft.; AK: 182.5-hoe ft.
AE-5 200442028 {126 1310 391 |-4u° | N85°W | NK: 0-10 ft.; BX:- 10-1O4 ft.; AX: 104-208 rt.;
. | EK: 298-391 ft.

AE-6. 1 1931.5] 1245 1329 | 323-« | -55° | s87°W | NK: 0-10 ft.; BX: 10-111 ft.;'AXs 111-323 ft.
AE-7 4-04 1613 |} 1104 1337-5 320 |-39° | n88ew z O710 ft.; BX: lO-41 ft.; AX: 41-134.5 ft.;

| EX: 134.5-320 ft.

4033 - ST -




Footage
Emon 6
45.5 496
496 600
600 624
62h. 640
640 649
649 686
686 7OL
TOL 730

4033

Percent

core recovery
39

73

19

81

69

87

49

Hole CH-1 (Cont'd.)

Desc.

ion

Black and dark-gray argillite containing
veinlets of white quartz and calcite-
abundance of pyrite as disseminations and
masses, some chalcopyrite can be noticed
intercalations of greenish-gray silicified
amphibolite containing masses of pyrite
which may have replaced dark-green chlorite.

Greenish-gray porphyry with numerous pele
ereenish-white phenocrysts, there are inter
calations of nonporphyritic greenish~-gray
ephenitic rock and occasional thin streaks
of dark-gray material. Pyrite is present
as disseminations and small aggregates
scattered but not abundant, a few milky
quartz veinlets with little calcite are
scattered through this interval.

As above to 602 feet; belance dark-gray to
black argillite alternating with pale
greenish-gray amphibolite; amphibolite
contains masses of darker green mineral,
probably chlorite. Pyrite is fairly
abundant as small aggregates disseminations
and veinlcts; also quartz and calcite to
62h, feet.

Pale-green amphibolite and porphyry, the
latter contuining greenish-white
phenocrysts, there are intercalations of
dark-gray to black argillite; pyrite is
present in veinlets and aggregates, most
abundant in the argillite.

Pyritized pale-green amphibolite and coarse-
grained graywacke, streaks of black argil-
lite.

Pale greenish-sray porphyry with large and
small greenish-white phenocrysts, few
quartz veinlets. -

Highly silicified greenish-gray rock; pyrite
is rather abundant as fine disseminations,
grains, and lenticular aggregates.

Pale-green, partly silicified amphibolite,
much of which contains irregular darker-
green masses; pyrite is present as aggre-
getes and grains particularly abundant at
704 feet.

- 34 -


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Stope: ae
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0. 40.2
ax ex
Hole No.!
° °
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a ew vow ay aw aw 7

Figure 10. - Collier mine, Calaveras County.


Drill Hole Data

North Keystone Mine

; Elevation | - i Hl
Coordinates | of | Depth, |
Hole | oN E__| collar, ft.|. feet | Dip | Bearing Size of core
i
K-Leeeee | 68 | 551 1006 . 593 | -80°/s43°w NX: 0-5 ft.; BX: 5-10 ft.; AX: 10-593 ft.
K-2 coeee | 1696.5] 756 1023 646 | -70°|Sh6Ow iNX: O-6 ft.; BX: 6-37 ft.; AX: 37-200 ft.;
BX: 200-204 ft.; AX: 204-212.7 ft.3; ©
BX: 212.7-255 ft.; AX: 255-512 ft.; EX: 512-646 ft.
K-3 eee | 1966 394.5 1018 571 | -72°|s47°30!w jNX: O-7 ft.; BX: 7-221 ft.3 AXs 221-4n7 Ft;
ps Wk7-571 ft. .
K-4 ...0. | 1863.5 | 852 1026 833 | -75° |ské°w WK: 0-27 ft.; Bk: 27-251 ft.; ax: 251-49 rt.;
EX: 40-833 ft. :

4033 - kT -




Footage Percent
From To core recovery
566 571 70
5TL 583 oT
583 602 .5 100
602 5 712 98
712 74 100
74 722 100
722 732 72
732 156 983
756 794 100
798 800 100

Hole N-2 (Cont'd.)

Description

Highly silicified and ‘epidotized schist,
brecciated and containing dark-gray gougelike
material containing stringers of pyrite and
chalcopyrite; these sulfides are distributed
through this crushed zone as small irregular
masses and veinlets.

Medium-gray, highly silicified schist con-
taining abundant pyritic disseminations and
veinlets, probably an intensely silicified
and pyritized chlorite schist, mundick (?)
of local miners.

Highly silicified and epidotized schist,
occasional thin intervals of medium to
dark-green chlorite schist.

Amphibolite schist, quartz veinlets, much
epidote disseminations and veinlets, some
banding of hematite, a few specks of
pyrite.

Amphibolite schist, considerable quartz, few
cubes of pyrite, and slightly chloritized.

Pale-green chloritized schist, a few quartz
veinlets.

Amphibolite schist, two small quartz veinlets,
ea few specks of pyrite.

Pale-green chlorite schist, a few quartz
veinlets.

Pale-green amphibolite schist with very few
quartz veinlets, some chloritization on
some planes of schistosity.

Pale-green highly silicified amphibolite
schist with few quartz veinlets.

Hole N-3
Location: 653 N., 942 E. Bearings S. 67° 45! w.
Elevation of collar: 12 ft. above collar Dips -73°
of min shaft Core size, feets
Depth: 800 ft. NX: 0-8
BX; 8-20
AX: 20-800

Footage Percent
From To gore recovery
(0) 20 56
20. ho 98

4033

Description

Partly altered green amphibolite schist
considerably banded with hematite.

Green amphibolite schist considerably banded
with seams of hematite, 3 feet of quartz
at 28.5 feet.

- 23.-


commercial copper ore in the unexplored area to the north of the mine openings.
Initial drilling was done in March 1943, and subsequent drilling was undertaken
in August 1943 and continued to December 1943.

The North Keystone mine, in sec. 34, T. 2N., RIQE., M.D. B. 8M, is
on the northern outskirts-of the town of Copperopolis in southwestern
Calaveras County, Calif. The area drains southeasterly into the Stanislaus
River. Creeks flow only in winter, as.summers are dry and warm and winters
are mild. A reservoir built to supply water for a 300-ton mill lies 400 feet
west of ‘the min shaft. Buildings and equipment consist of a 70-foot head-
frame, ore bins of 300 tons capacity, hoist house in which is installed a
double-drum hoist and one large and three small stationary air compressors, a
blacksmith shop, timber-framing shed, storehouse, lamp house, and an office.
Electric power is obtained from the Pacific Gas & Electric Co. high-tension
transmission lines, which traverse the property.

The district is accessible over hard-surfaced roads from Stockton by
following State Highway 4 eastward for 40 miles. Angels Camp, 12 miles to
the northeast, is the shopping center for the area. The nearest rail shipping
point is Farmington, on a branch line of the Southern Pacific Railroad: 25
miles west of Copperopolis via Highway 4.

History

. The Copperopolis Lode was located in 1861. ‘The furor resulting from this
discovery was culminated by the staking of hundreds of claims. Only the
Union, Keystone, Empire, and North Keystone claims have been productive.
Approximately 72 ,600 000 pounds 9/ of copper was won from the ores of the
Copperopolis Lode from 1861 through 1946, and mining operations have been
carried to a depth of 1,800 feet. .

Information as to early activity at the North Keystone is sketchy. The
Engels Copper Co. developed and-operated the property between 1927 and 1930
by sinking a 675-foot, 3-compartment, vertical shaft and by driving over 3,000
feet of development from four levels. Owing to the low price of 5 cents a
pound for copper at the time, operations were stopped after considerable ore
had been blocked out. In 1ghe, the property was leased by the owners,
Calaveras Consolidated Mining Co., Ltd., to the Keystone Copper Co., a limited
partnership, principals of which include H. Bush, C. W. Stewart, and C. E. Nuss.
A pumping and rehabilitation program was inaugurated, and production was
started immediately after its completion. In July 1943, the Keystone Copper
Corp., principals of which dre the Keystone Copper'Co. of Copperopolis, Calif.,
and the Lava Cap Gold Mining Corp. of Nevada City, Calif., was formed to
operate the property.”

During the period from July 1942 to July 1, 1945, about 5,000 tons of
copper was produced from the mine output of 225,549 tons of ore -10/

‘Q/ Copper in Californias: Division of Mines, State of California, Ball. 1,
1948, pp. 96-97.
10/ Otto, Schiffner, general manager, Keystone Copper Corp.

4033 . 7 &-


. Hole N-3 (Cont'd.)

Footage Percent
Erom Zo core recovery Description
153 765 98 Massive sulfide vein carrying pyrite and
chalcopyrite.
765 TTO ge Highly pyritized gray-green amphibolite

schist considerably banded by seams of
fine pyrite, may be so called mmdick of
local miners.

TTO 800 98 Light-green silicified amphibolite schist,
much epidote disseminations, in masses
and veinlets, few white quartz veinlets.

Hole N-4
Location: 892 N., 530 E. Bearing: S. 60° W.
Elevation of collar; 34 ft. above collar Dip: -60°
of main shaft Core size, feet:
Depth: 700 ft. NK: 0-15
Bs 15-30
AX; 30-700
Footage Percent
From To core recovery Description
io} 30 38 Surface altered amphibolite schist, iron-

stained on fractures and small rusty
quartz veinlets.

30 oh 27 Green amphibolite schist cut by occasional

: quartz and calcite, little epidote veinlets,
slightly chloritized on planes of
. schistosity.

oh 160 50 Pale-green amphibolite schist considerably
chloritized, few white quartz and calcite
veinlets, much massive, veinlets and dis-
seminations of epidote, fractures filled
with dark-green chlorite.

160 171 65 Green amphibolite schist, few quartz veinlets,
considerable epidote in veinlets, generally
quite massive.

171 210 58 Light-green amphibolite schist cut by a few
tiny calcite veinlets, very little quartz,
much epidote in thin veinlets and dissemin-
ations, slightly chloritized.

210 230 75 Greenish-gray schist (uralite?), considerable
banding due to epidote in seams, fractures
filled with dark-green chlorite, small
amount of scaly pyrite.

230 245.5 57 Green amphibolite schist somewhat silicified,
fractures filled with dark-green chlorite.

4033 - 26 -


Location:
Elevation of collar:

800 feet.

Depths

Footage
From Zo

Ce) 16
16 19
19 26
26 39
39 43
43 71
7 82
82 96.5
96.5 100
100 104.5
104.5 118
118 128
128 133.65
133.5 143.5
143.5 156
156 = 189
189 233
2330 263.5
263.5 269
269 289
289 296
296 300
300 311
31l 321
4033

755 Ne, 2152 EB.

Hole CH-2

Bearing: S. 60° 45! w.

36 ft. below collar Dip: -52°
of Hobo shaft. NK: O-10 ft.
AX: .23-300 ft.
BXs 10-23 ft..
EX: 300-800 ft.
Percent
core recovery Description
8 Surface altered amphibolite.

76 As above, with few stained quartz veinlets.

59 Surface altered amphibolite.

62 Partly altered amphibolite (brownish) .

55 Approximate bottom of surface alteration.

48, Pale-green amphibolite with scattered quartz
veinlets (white).

100 Pale-green silicified amphibolite with few
scattered veinlets of white quartz.

oh Pale-green amphibolite with few scattered
veinlets of white quartz.

66 Pale-green amphibolite.

100 Green silicified amphibolite, some green
chlorite?

83 Green amphibolite with white quartz veinlets;
some epidote disseminated throughout.

100 Pale-green amphibolite with epidote in
disseminations, some pyrite scattered
through this interval.

100 Pale-green amphibolite with tiny veinlets of
epidote.

88 Pale-green porphyry, light-colored phenocrysts,
some epidote in tiny veinlets - silicified.

90 Light-green amphibolite with tiny veinlets of
white quartz and epidote, graywacke from
151.5 feet on considerable white quartz at
155 feet.

86 Silicified light-green amphibolite with
scattered white quartz veinlets.

72 Pale-green silicified amphibolite.

Th Pale-green silicified amphibolite with
scattered tiny white quartz veinlets.

100 Light-green porphyry with cream-colored
phenocrysts with irregular boundaries.

79 Light-green silicified amphibolite with a few
tiny white quartz veinlets.

100 Pale-green silicified amphibolite.

17 Pale-green silicified amphibolite with quartz
veinlets.

4L Pale-green silicified amphibolite.

3h As above with scattered white quartz veinlets.

- 35 -




1400.

Dato 4

958 Zn. 0.09% Cu,
B0Rh 00S Rte on, aay 1200

BUL-3U9.5" 3.81% Zn. 0.97% Cu.
0.004 Oz. Au. 0.455 On. Agea
_ 105
370.5-395" 2.427 Zn, "
1000- Ors Cu.
“ woo
SECTION THROUGH DRILL HOLE 4 SECTION THROUGH DRILL HOLE 2 SECTION THROUGH DRILL HOLE 6

~—1400

EAST _ NORTH DD Hp S [po

290-305" 1.93% Zn. 0.09% Cu,
0.014 Oz. Au. 0.96 Oz. Age

\

SECTION THROUGH DRILL HOLE S SECTION THROUGH DRILL HOLE 7 LONGITUDINAL SECTION A—A'

GENERALLY SCHISTOSE FRASMENTAL ROCK
Mave VARTING OCEREES OF SERICITIZATION
V5} ano siticinicarion.

rear © re.ae_ ronment

Scale In Feer

Figure 13. - Vertical sections, American Eagle claim, Mariposa County.


Location, Physical Features, and Commnications

These claims, in sec. 30, T. 4 S., R. 16 H., Mariposa County, Calif.,
lie on a ridge of the Sierra Nevada foothills at altitudes ranging from 1,300
to 1,500 feet. The ridge, which has a general north-south trend, is for the
most part denuded and slopes sharply to the east and west for a relief of 500
feet. Climatic conditions are typical of the lower foothill belt; summers
are long, dry, and hot, and winters are mild. An average of 16 inches of rain
falls annually.

Vegetation consists principally of grass, but the upper parts of ridges
and hills support brush, scrub oak, and pine. Drainage is westward and
northward into the Merced River, which traverses the area. At a point
approximately 11/2 miles west of the claims, the river elevation is 450 feet.

There are no buildings on the property, and it is wholly unequipped. It
is accessible from Merced, Calif., via Snelling, Merced Falls, and Hornitos
over 36 miles of surfaced State highway and 5 miles of road that was partly
constructed and completely graveled through Federal access-road funds. The
nearest rail shipping point was Merced Falls, 15 miles from the property, but
is now abandoned.

Qre. sits

There is no recorded production for this group of claims, although
unconfirmed shipments of ore are supposed to Mave been made from the American
Eagle. The only possible evidence in support of this is a small stope and
glory hole from which a few tons of ore could have been mined.

Surface workings are made up of shallow shafts, test pits, open cuts, and
trenches scattered throughout the claims. As shown in figure 12, underground
development on the American Eagle consists of an adit crosscut extending
eastward from its portal for a distance of 300 feet, and from this drifts to
the north and south 230 and 190 feet long, respectively. In addition, from
the drift to the north are several short crosscuts and drifts off from them,

a 40-foot winze, a small stope, and two raises that hole through to the surface.
There is no evidence that lateral underground prospecting was done on either
the Blue Bell or the Bonanza claim.

In Mariposa County the foothill belt is characterized by a wide band of
schist that extends along the western boundary for a strike distance of 40
miles. About midway in the belt lies the Blue Moon mine, which during the war
produced more than 13,000,000 poundsl8/ of zinc and was the largest single
zinc producer in the State.

The American Eagle claim adjoins the Blue Moon on the south, and their
mineralization is similar. The prospect openings on the American Eagle group
of claims are in a belt of steeply dipping sericite schist that traverses the
property in a north-south direction.

16/U. S. Bureau of Mines, Minerals Yearbook, 1944 - p. 275, and 1945 - p. DBS «

4033 - 15-


Footage
Exon pic}
32 he
42 60.5
60.5 84.65
a
104 12h
12h 129
129 151.5
151.5 186.5
186.5 211.5
211.5 266.5
266.5 271.5
271.5 276.5
276.5 300
300 321
321 328
328 336
336 360
360 406
406 429.5
99.5 4Be
456 4o1

4033

Percent

core recovery
9T

98
8B

100
oT

0
100
99
99
oh
87

5h
80

81

100
99
19
7
53

Hole CH-3 (Cont 'd.)

Description

Pale-green amphibolite, few quartz veinlets.

Pale-green porphyry, few quartz veinlets.
Pale-green amphibolite with few quartz
veinlets.

Pale-green silicified amphibolite, few quartz
veinlets.

Pale-green silicified amphibolite porphyry.

1 foot quartz vein 95 to 96 feet, balance
silicified amphibolite and porphyry.

Pale-green, silicified amphibolite; zones of
porphyry.

Pale-green, silicified amphibolite; some
porphyry.

Highly silicified pale-green amphibolite and
quartz veinlets.

Pale-green silicified amphibolite; quartz
veinlets.

Highly silicified, pale-green amphibolite;
numerous quartz veinlets.

Silicified pale-green amphibolite with quartz
veinlets.

Silicified green amphibolite quartz veinlets,
few specks pyrite at 270 feet.

Silicified green amphibolite quartz veinlets,
little pyrite at 274 feet.

Silicified green amphibolite quartz veinlets.

Chlorite amphibolite; veinlets of quartz and
epidote; also disseminated epidote.

Chlorite amphibolite; veinlets of quartz and
epidote; also disseminated epidote. From
323 to 328 feet siliceous vein mterial
carrying sulfides, mostly pyrite, some
chalcopyrite.

Chlorite amphibolite; quartz veinlets; some
talc on schistosity.

Chlorite amphibolite; quartz veinlets; some
talc on schistosity planes.

Silicified amphibolite; few quartz veinlets
and disseminated epidote; few specks pyrite.

Chloritized amphibolite.

Chlorite amphibolite.

Chlorite amphibolite to 4#2 feet;.then 3 inch
quartz stringer; rest chloritized amphi-
bolite schist. .

Chloritized amphibolite schist, minor amounts
of disseminated pyrite; some talc on certain
planes of schistosity.

- 38 -


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Hole N-3 (Cont'd.)

Footage Percent

From Do core recovery Description

409 423 42 Greenish-gray chlorite schist, few veinlets
of quartz and calcite.

423 436 90 Green amphibolite schist somewhat chloritized ,
quartz breccia (epidote and green schist
cemented by white quartz) between 432 and
435 feet.

436 YG 60 Green chloritic amphibolite schist with few
white quartz veinlets, scattering of pyrite,
disseminations and veinlets of epidote.

4he 470 92 Light-green chloritized amphibolite schist,
few quartz and epidote veinlets, epidote
disseminations.

470 479 85 Green. amphibolite schist finely banded by
hematite and epidote, few white quartz
bands, chloritized on schistosity planes.

479 483 95. Green amphibolite schist slightly chloritized.

483 519 ob Light-green silicified amphibolite schist,

much epidote disseminations and veinlets,
few quartz and calcite veinlets.

519 5k 16 Green amphibolite schist, much epidote as
veinlets, masses and disseminations, very
few quartz veinlets.

545 570 92 Light, pale-green. amphibolite schist, many
epidote veinlets, few quartz veinlets,
me silicified.
570 580 98 Light greenish-gray chlorite schist showing

scaly pyrite, mich of this interval broken
and cemented by quartz.

560 602 66 Green chlorite schist, many epidote veinlets.
602 636 32 Dark-green amphibolite schist, some epidote.
636 666 67 Green amphibolite schist, some disseminations

and many veinlets of epidote, few tiny
quartz veinlets (chloritized).

666 686 oT Grayish-green amphibolite schist (uralite),
massive, with few tiny veinlets of white
quartz slightly chloritized.

686 109 92 Grayish-green amphibolite schist, much epidote
disseminations and veinlets, considerably
silicified from 689 to 709 feet.

709 Be oT Light-green amphibolite schist, much epidote

. disseminations and veinlets, many tiny
fractures filled with hematite giving
speckled lavender appearance, somewhat
silicified.

732 753° 99 Green silicified amphibolite schist, much

. epidote disseminations and in masses, few
quartz veinlets from 730 to 72 feet,
scattered areas have tiny hematite filled
fractures.

4033 - a5 -


Footage
From Do
THO 850

-850 855
855 865
865 880
880 883
883 890
890 910
910 85
935 gho
gho 970
970 984
984 990
990 1000
1000 1030
1030 1036.5
1036.5 1038
4033

Percent
core recovery

70

100
100

100

100

67

46

80

8

oh

100
100

My

aT

1o

Hole N=5 (Cont'd.)

escription

Pale-green amphibolite schist, mich epidote
disseminations and some veinlets, few tiny
veinlets of quartz and calcite, few specks
pyrite, considerably silicified, banding
due to hematite from 812 to 620 feet.

Green amphibolite schist, much quartz, some
pyrite.

Grayish-green amphibolite schist, much epidote
in tiny veinlets, few veinlets of quartz,
scattered specks of pyrite.

Dark bluish-green silicificd amphibolite
schist, few small quartz veinlets, scattered
pyrite.

Grayish-green amphibolite schist, many epidote
veinlets...

Dark-green amphibolite schist, few tiny
epidote veinlets, quartz veinlet at 889
feet.

Green amphibolite schist, few epidote
veinlets, some fractures filled with dark-
green chlorite, much quartz 905 to 910 feet,
little pyrite scattering.

Light-green amphibolite schist, mach dissem-
inations and veinlets of epidote, few
quartz veinlets, slightly chloritized on
planes of schistosity.

Grayish-green amphibolite schist (uralite?)
considerably chloritized. “
Greenish-gray amphibolite schist (uralite?)

considerably chloritized.

Light~green amphibolite schist, much epidote
disseminations.

Green amphibolite schist, chloritized on
planes of schistosity, some epidote dis-
seminations.

Yellowish-green amphibolite schist, much
épidote disseminations, scattered fine
bands of hematite.

Green amphibolite schist, considerable
epidote disseminations, scattered bands of
hematite, some quartz, considerably
chloritized.

Green amphibolite schist, considerable dis-
seminations of hematite and some hematite
in bands, disseminations of epidote, con-
siderably chloritized, leached appearance.

Sulfide vein showing good chalcopyrite and
pyrite.

-31-


COPPER HILL MINE

The Copper Hill mine is situated in sec. 34, T. 8 Ne, Re 9 E«; NE 1/h
of sec. 3, T. 7 N., Ro 9 E.3 and NE 1/4 of NW 1/4 of sec. 3, Te 7 Ne, Re 9
E., M.D. B. & M., in the extreme northwest corner of the Jackson Quadrangle,
Amador County, Calif. It may be reached by following a surfaced county road
west from Plymouth, Calif., for 6 miles, past the Detert ranch, thence north
on the Latrobe Road for 2 miles, and thence 2 miles west on a poorly
conditioned dirt road to the mine. Sacramento is the nearest large supply
center and is about 45 miles distant. Ione is the nearest rail shipping
point.

The area in the vicinity of the mine is drained by Indian Creek, a north-
westward flowing tributary of the Cosumes River.

History

The history of this property is obscure as all old mine records and maps
were destroyed by fire. Development and mining must have been carried out
near the turn of the last century, as a California State Mining Bulletin dated
1906 states that "large slag dumps show that considerable ore had been
produced in the past,” and that "there are over 1,200 feet of shafts and over
1,800 feet of drifts on the property.” Old smelter records attest the fact
that the ore shipped from this mine contained a high percentage of copper and
Zinc as well as an appreciable amount of gold and silver.

The property is owed by the W. F. Detert estate, 1705 Mills Tower, San
Francisco. At the time of the Bureau's exploration it was optioned tq
J. P. Donovan of San Francisco, who had, in tum, optioned it to the American
Smelting & Refining Co.

Geology and Mine Workings

The deposits on this property occur in silicified amphibolite schists.
Gossan-capped veins strike west of north and dip 45° to 65° eastward. The ore
consists of an intimate mixture of fine-grained pyrite, chalcopyrite, and
sphalerite and occurs in relatively short lenses of varying widths. Small
amounts of gold and silver are contained in the sulfides. From surface
indications it appears that there has been faulting between the min shaft and
the Hobo shaft.

Work Performed by Bureau_of Mines

Five diamond-drill holes ranging in length from 315 to 800 feet were
drilled along the strike of the veins. The logs of these holes are given in
the appendix. One drill, operating most. of. the time at a rate of three shifts
per day, was operated 6 days a week under contract. This drilling (aggregating
2,864 feet) consisted of 38 feet of "NX" hole, 85 feet of "BK" hole, 1,781
feet of "AX" hole, and 960 feet of "EX" hole. Six hundred and ninty feet of
casing was set, and 427 feet of hole was cemented. Core recovery was 72.8
Percent. Forty-six core and 65 sludge samples were collected for analysis.

4033 -5-


INVESTIGATION OF WEST BELT COPPER-ZINC MINES
EL DORADO, AMADOR, CALAVERAS,
AND MARIPOSA COUNTIES, CALIF.

By FRANK J. WIEBELT, W. C. SANBORN, R. R. TRENGOVE,
AND SPANGLER RICKER

* «* «© # «© «© « « « Report of Investigations 4760

UNITED STATES DEPARTMENT OF THE INTERIOR
Oscar L. Chapman, Secretary
BUREAU OF MINES
James Boyd, Director

Work on manuscript completed October 1950. The Bureau of Mines will welcome reprinting
of this paper, provided the following footnote acknowledgment is made: “Reprinted from
Bureau of Mines Report of Investigations 4760.”

February 1951


The ore minerals.are sphalerite, pyrite, and chalcopyrite associated with
barite and a siliceous gangue. Oxidation has extended 2 to 50 feet below the
outcrop. Both ore shoots were mined originally for gold and silver.

Work Performed by Bureau of Mines

From July to September 1944, 1,355 feet of diamond drilling was completed.
Surface plan and hole cross sections are shown on figures 10 and 11, and
additional data are listed in the appendix.

Two holes, Nos. 1 and 2, explored the ground below the recent mine
workings , and two holes, Nos. 3 and 4, were drilled below the old workings.
Low-grade mineralized material was found in all holes.

AMERICAN EAGIE MINE
Introduction

Zine production of Califomia, which in 1943 totaled 3,712,00019/ pounds ,
has in general been of minor significance in the mineral production of the
State. The quota-price basis for zine purchase by the Metals Reserve Company
placed the potential producers of this metal on a more favorable basis and
justified exploration on some of the better prospects. The American Eagle
property adjoins the Blue Moon property, which at the time of the Bureau's
examination was being mined by Red Cloud Mines, Inc., a subsidiary of the
Hecla Mining Co. of the Coeur d'Alene district of Idaho.

The Federal Bureau of Mines initiated a diamond-drilling Program at the
American Eagle mine based on an examination by one of its engineersl6 / in June
1943. Drilling was done from January to March 1944,

History and Qwnership

The American Eagle mine, first mown as the Bullion Hill property, consists
of three patented claims - Bonanza (5718), Blue Bell (5718), and American Eagle
(5719)

Authentic information on past prospecting was not obtainable. It was
reported that the American Eagle claim was located in 1893 as a gold claim
and that it was patented in 1908 -1z/ Numerous shallow shafts and open pits,
an adit level, a small glory hole, a winze, and old foundations for a mill are
evidence that the property was prospected with considerable vigor and optimism.

The Blue Bell and Bonanza claims are held jointly by Edward C. Morrison of
Korbel, Calif., and by Lorenzo J. Alonzo, Norbert C. Alonzo, Phillip T. Alonzo,
and Andrew Valberde of Portola, Calif. The American Eagle claim is held equally
by Valberde and Morrison arid by Irene G. Kopp, of Santa Clara, Calif.

J. 4H, A. Williams, of New York City, had a purchase option on the property.

15/U.S. Bureau of Mines, Minerals Yearbook, 1943, p. 283.
li T6/ utner, D.W., mining * engineer, Region II, U. S. Bureau of Mines.
Ij/ 3. H. A. Williams, New York City.

4033 - uh -


Record of Diamond Drill Hole Values

North Keystone Mine

Fole; K-1 Depth: 593 feet
Iocation: 1468 N.; 551 E. Dip: -80°
Elevation of collar; 1,006 ft. Bearing: S. 43° w.

Core size; WX: 0-5 ft.;
BX: 5-10 ft.;
AX: 10-593 ft.

Size of Core i Sludge

i Feet core Cu, percent Au, OZe Ag, oz. |! Cu, percent | Au, oz. AB, OZ.

4.0 AX - - i - 0.23 i 7 ~
10.0 AX - - - +10 - -
8.0 AX #0 ..02 - - - - -
1.6 AX * 02 - - - - -

j 3-4 AX *.02 - - : - - -
5.5 AX * 02 - - - - -
2.0 AX - - - 20h - -
4.0 AX * 02]

- os 29 - -
2.0 AX ep
3.40 AX * 02 - - - - -
3.0 AX 03 - - - - -
5.0 AX * 02 - - - - -
4.8 AX 205 - - - - -
42 AX “79 0.29 0.01]
Pa 1.31 Trace None
1.3 AX 10.03 - - J
3.2 AX 9.30 ld Hi 01 3.70 0.10 Trace
1.0 AX «16 - | - i - - -
1.0 AX 04 - - - - -
9.0 AX - - - 37 - -
7.0 AX -. - - i 12 - -
6 AX 98 - - - - -
10.0 AX - - - -06 - -









Newton mine

Holes N-3 Depth: 800 feet.
Location: 653 N.: 942 E. Dip: -73° °
Elevation of collar; 12 ft. above collar of main shaft. Bearing: S. 67 45! we

Core size: NX, 0-8 ft.; BX, 8-20 ft.; AX, 20-800 ft.

i Percent | Size Analyses co
core of .Core Sludge
From: Tos Feet rec. j core | Percent Cul Percent Zn' 0Z. Au_ Oz. Agi Percent Cuj Percent Zn | Oz. Au! 0z. Ag
= ; H {

13 155 2.0 Ax | 0.65 | Trace | 0.30
153 156.5 | 3.5 ax ; 4.50 0.51 0.01 | Trace |

756-5 | 757-7 | 1.2 AX | 52. 10 Trace | None

157-7 | 761.5 | 3.8 AK | 91 +05 i | \ i

761.5 | 765 1 3.5 ! ax f 261 None None Trace! H |

155 76 | 10.0 | Ax | +95 | Trace | None
765 “766.2 1.2 AX | 1.23 16 None | 0.90 i | i

765 TIO 50 : ! | 60 i \ "| Trace
Holes N-=5 Depth: 1,076 feet
Location: 796 N.; 1148 E. Dip: -73°

Elevation of collar: 28.7 ft. above collar of: main shaft Bearing:, S. 57° 30° W.

Core sizes -NX, 0-6 ft.; BX,.6-20 ft.; AX, 20-1,076 ft.
6 "| 156 | 70 i | AX | | Tracé”) None , | i |
156-158 2 tax | i pom tomy i i
1036.5 | 1037 0.5" | ax | 9.0h | f = | * | 5.58 0.6" Trace | 0.70
1037 © | 1038 1 AX | i i \ | 2.93 6 " 550
2 | AX | we | lou | " 0.30 | = 1.00 oh " +30
Ll i

1038 | 1oho |

i
1/ Less than.

4033 18 -




‘$70 Blue eon

Datum Assumed

Brunton Survey

e— Diamond Drill Hole
eShoft = Trench en ____ 20
> Enlarged Trench OF pit Seale i Feet

‘Seale In Feet

Figure 12. - Plan of American Eagle claim, Mariposa County.


American Eagle Mine (Cont'd.)

Hole: AE-5 Depth: 391 ft.

Location: 2028 N.; 1262 wW. Dip: 44°

Elevation of collar: 1,310 ft. Bearing: WN. 85 W.
Analyses

Footage Size of Core Sludge

From: To: [Feat core Cu, percent | Zn, percent | Au, 02.) Ag, 0Z.!-Cu, percent jZn, koreans | Au, oZ.{| Ag, oZ.

288° 729.7 | 2.7! AK *0 02 *O0.1 |. Trace None j

288 | 202.5 | Wj ax | 0.02 *0.1 | Trace | None

292.5 }29h | 1.5] ax | *.02 el of? « *.02 a | o [os

29h 1295.9 | 1.9 AX * 02 *.1 " 0.20 | |

20h 1296.5: 2.5) ak *.02 6 | ! 9.20

296.5 | 297.5 | 1.0 AX * 02 1 | " None | |

296.5 | 298 | 1.5); Ax I * 02 *.1 "5 20

298 , 300 2.0 EX O07 2 | “ 0.20 | | H

298 | 302 3.0}. Ex ' 4 202 oh * 1.20

301 1305 | koi Ex £03 ao} None | | |

jor 1305.5 -b5 | ex | i | 2k 6” None

*Less than. “

Hole: ~AE-6 : Depth; 323 ft.

Location: 1931.5 .N.; 12h5 w. ips ~55°

Elevation of collar; 1,329 ft. Bearing: S. 87° Ww.
Analyses

Footage Size of Core H Sludge

From: | Tos jFeet core | Cu, percent i 2n, percent | Au, oz. /Ag, oz. | Cu, percent jZn, percent | Au, 0Z. | Ag, 02.

WT 73.2712 AX 0.07. | *0.1 Trace | None |

13.2 |u| .9 | ak oh | ol " 0.35 |

253 1258.5 | 5.5 Ax | #0 202 *0.1 Trace | 0.20

258 {238-5 5 AX «Oh *.1 ” 225

258.5 |260.7 | 2.2 Ax +05 *.1 0.015 | 1.15

261 265 ko AX 05 #1 005 “15

261 .|266 | 3-0 AX +02 1.5 0.005 | 1.00

289 5293 ie) AX 202 *.1 Trace None * 02 3 Trace | None

293 [2074 | 4k Ax 02 *1 * "

2974 1300.4 | 3.0 AX * 02 *1 , =" | "

4033

-61-


General Geology and Description of Deposits11/

The stratified rocks of the region, more than 2,000 feet thick and
belonging to the Amador formation, consist largely of greenstones, green
schists, and slates. Intercalated with the greenstone and schist in the
vicinity of the mines are several layers of argillaceous slate 100 to 200
feet thick. These rocks are steeply tilted, so that they strike about N. koe
W. and dip 65° to 85° northeast. A regional schistosity strikes northwest
and dips in general 70° to 85° northeast.

Intrusive rocks in the vicinity of the mines include granodiorite, diorite,
serpentine, and hornblende diorite. Granodiorite, abundant in both the North
Keystone mine and the area to the northwest, forms large and small lenticular
bodies parallel to the strike and dip of the enclosing rocks.

A strong fault, prominent in the mine but not easily located on the surface
because of poor exposures, trends parallel with the regional strike and dips 65
to 75 degrees northeast. It forms the footwall of a zone 5 to 45 feet wide in
the mine, which contains all the proved ore bodies. The fault is theréfore
designated as the footwall fault. Between this fault and the greenstone in
the hanging wall of the ore zone, the rocks consist of intensely chloritized
slate, schist with varying degrees of chloritization, and granodiorite
generally much sheared and partly chloritized,.

Ore bodies in the mine are composed of innumerable anastomosing veinlets
of fine-grained pyrite and chalcopyrite as well as veins a few inches to 2
feet wide of massive sulfides in chloritized slate or schist. ‘The boundaries
of the bodies are fairly sharp and are generally surrounded ‘by halos of
pyritized rock a foot or two thick. Bodies so far mined are confined to
chlorizited slate. They are believed to be more or less elliptical in
longitudinal section, with lenticular cross sections, and lie approximtely
parallel to the footwall fault and to the schistosity of the enclosing rocks.
The widths of the ore lenses range from.2 to 20 feet, and the know strike
lengths are 60 to 300 feet. In the direction of the "rake, which is 75 to 80
degrees to the north, the “larger bodies are prohably 500 to 900 feet long.
The rake of the dodies maybe controlled by the’ pitch of rolls in the footwall
fault, but exposures in the mine and the accuracy of existing surveys of the
mine are insufficient to substantiate this. Where the granodiorite in the ore
zone is abundant, thus restricting or pinching out the chloritized slate, as
in the north part of the 375 level and at the north ends of the 525 and 675
levels, only stringers of chalcopyrite in narrow layers of chloritized slate
or schist or in zones of sheared and chloritized granodiorite are found.

Mining

Previous to the present operations, the North Keystone property had been
developed and operated on a modest scale through several small and relatively
shallow shafts, but principally through the main shaft. Its three compartments,
with over-all dimensions of 6 by 16 feet, extended vertically to a depth of

il/ Hadley, J. B., U.S.G.S., Preliminary, Report on Results of “Bureau of Mines
Exploration at the North Keystone Copper Mine, Dec. 18, 1943.

4033 -9-



Hole AE-6 (Cont'd.)

i Analyses
Footage Size of | Core fl Sludge

From: To: | Feet core | Cu, percent | 2n, percent | Au, oz.| Ag, oz. |! Cu, percent; Zn, percent | Au, oz. Ag, oz.
300.41302.8] 2.4) ° AX i 2h 3.3 Trace 0.60 | i T
293/303 | 10.0] aK (0.08 | 045 trace | 0.20
303 | 304.8] 1.8] ax 205 9 " | vone | -
304.8 | 308.5] 3.7] Ax * 02° #1 op | | . H
303 | 308.5] 5.5] ax | | oh | TM None
308.5] 313) 4.5! ax | ! 05 | ¥ "| 0.20
*Less than. ~
Holes AE-7 Depth: 320
Location: 1613 N.; 1104 w. Dips -39
Elevation of collar: 1,337.5 Bearing: N.88° w.

| i Analyses

Footage , Size of Core Sludge

Eromy 1 To: Feet core. | Cu, percent | Zn, percent jAu, 0%. Ag, oZ. | Cu, percent! Zn, percent :Au, 02. jAg, oz,
2ho (250 710.0 / EK y I | | 0.07. 0.5 ° |) Trace | None
29. 5 | 250 5 EX 0 04 *O.1 | Trace | 0.40 - | | H H
250 ~ | 251.2 | 1.2 EX 07 ¥.1 | 9.060 | 2.50 | \ \
2% [235° | 500} BX i | 2B 2 | 0.005 j os
255 | 255.5! 25 EX 18 +L | rece i None . \
255 1260.0 5.0 EX ! ' 03 |, ¥l Trace .20
260 (26.3) 3); Ex * 402 1.5 | 9.005 | 0.50 |
260 265 1 5.0 | Ex | : i 205 *1 " + 20
265 270 | 5.0 | EX ; | i *,02 ° 6 " “55
270 e72 | 2.0 EX 02 *,1 | Trace B0 | |
280 |283.2; 3.2| =x +04 el yo" 120 | |
280 285 5.0 EX | * 02 2 * 220
285 | 286.7 | 1.7 EX 15 2.2 0.08 “90 |
285 290 5.0 EX Oh al 0.015 1.60
290 |290.8| ~: EX 120 5 005 «| «2.70 |
290 | 295 5.0. EX 07 1.6 2025 1.50
295. | 295.1 1 EX 07 2h Trace 40
295 1300 | 5.0] Ex +10 2.0 .010 +95
300 301.3} 1.3 EX 16 3.6 0.005 hd
300 305 | 5.0 EX 08 2.0 2005 ho
3051310 5.0 | EX +06 1.8 Trace 45
*Less than. - @-

Interior - Bureau of Mines,

Pittsburgh, Pa.


9 100 200 FEET.

SCALE

(710 JACKSON

HIGHWAY

STATE

D.Hole| .N-2
3°

~ 2
Dip - 7:

Figure 2. - Drill-hole locations and underground workings, Newton mine, Amador County.


Hole CH-1 (Cont'd.)

Footage Percent
From to core recovery Description
199 206 98 Gray-green porphyry (matrix is uralite and

quartz, some fine disseminated pyrite
scattered throughout.

206 ehh 99 Pale greenish-gray massive rock, probably a
graywacke or graywacke breccia-pyrite, is
present in numerous fine veinlets.

ahh 251 81 Green amphibolite containing numerous small
irregular masses of dark-green chlorite-
pyrite is present in minute grains
scattered.

251 291 77 Pale-green amphibolite containing numerous
small, irregular masses of dark-green
chlorite, occasional tiny veinlets of white
quartz with epidote, and small amount of
calcite.

291 315.5 87 Green amphibolite, few small veinlets of
white quartz with epidote, and little
calcite.

Light-colored phenocrysts with irregular
boundaries, aphanitic groundmass probably
uralite, intercalations of green
amphibolite with numerous small masses of
dark-green chlorite.

315.5 356 76 Gray-green porphyry with dark-green
phenocrysts in fine-grained matrix. Pale-
green amphibolite schist, somewhat
silicified. Scattered tiny msses of pyrite
can be seen.

356 398 66 Pale-green, massive, silicified rock, some of
it brecciated and recemented with silica;
pyrite generally associated with quartz in
thin veinlets and isolated masses as above
to 286 feet. From 280 feet medium and
dark-gray highly silicified rock, some
resembling clastic structive and some a
brecciated dark slate, ebundance of finely
disseminated pyrite as well as in masses.

398 406 8h Pale-gray, fine-grained, readily friable
material probably gouge, mostly -60 mesh
but some angular grains 20 mesh or greater.

406 WLS 65 91 Greenish-gray and dark-gray porphyry with
light-colored phenocrysts-intercalation of
silicified dark-gray to black argillite,
much of which contains pyrite in veinlets
and disseminated; lesser pyrite in the
porphyry.

4033 - 33 -


Hale K-1 (Cont'd.)

Analyses
Footage Size of Core : Sludge
From: To: Feet core Cu, percent i Ausoz. | Ag, oz. Cu, percent | Au, oz. | Ag, oz.
47 453 6.0 Ax | 0.05 |
583 587, 4.0 Ax ! i 205 f i
Hole: K-2 Depth: 646, feet
Location: 1696.5 N.; 756-E. Dips -70°
Elevation of collar: 1,023 ft. Bearing: S. 46° w.
Analyses
Footage Size of Core ! Sludge

From: Tos I Feet core Cu, percent Au, oz. | Ag, oz. Cu, percent Au, 02. Ag, oZ.
128.5 | 128.8 | 03 Ax 208 ae L | : 4
128.5 |. 129.3 8 Ax i 0.69 i -
466.0 |. 466.3. 3 AX 7.05 i ~
466.3 | 468.1 | 1.8 AX 206, i
465.2 473.7 | 8.5 “AX 56 :
473.7 | 476.5 | 2.8 AX +15 |
473.7 | 480.5 | 6.8 AX 215
524.3 | 534.9 | 10.6 EX 05
534.9 | 541.9 | 7.0 EX 01
547.5 | 548.5 | 1.0 EX +20 |
548.5 | 548.6 el EX 1.18 | }
548.5 | 548.7, 2 EX 3.29 |
549.0 5498 8 EX 65 i

. 8 . EX 14
2B 8 2349 6 2 EX -16
554.9 | 555-1 2 EX 29
555-1 | 555.7 6 EX 2.27 |
555.7 | 556.5 8 EX oh i j
554.9 | 565.1 | 10.2.|. EX +19 H
574.0 | 574.5 5 EX 1,12
565.1 | 575.1 | 10.0 EX \. +2
4033 - 49 -



APPENDIX

Newton Mine

Hole N-1
Location: 517 N., 1242 E. Bearings S. 67° 30' W.
Elevation of collar: 40 ft. above collar Dips -45°
of main shaft. Core size, feet:
Depth: 882 ft. MX: 0-6

‘ BX; 6-20

AX; 20-882
Footage Percent
Erom Lo core recovery Description
i) 20 31 Amphibolite schist.

20 35 23 Weathered green chlorite schist, lens and
veinlet quartz.

35 AL 50 Green chlorite schist, with semitransparent
quartz, approximately base of weathering.

yl yy 8 Green chlorite schist, quartz veinlets
containing epidote.

ats 5h 8 Green chlorite schist, numerous quartz veins.

Sh 64 31 Green chlorite schist, large amounts of
introduced epidote and quartz in first
foot, occasional specks pyrite, chalco-
pyrite and carbonate.

64 67 90 Sericitic pale-green schist, greasy luster,
11 small veins calcite.

67 68 20 Quartz and fine-grained epidote in green
schist.

68 72 85 Epidotized green schist, veins quartz and
lesser calcite, some pyrite.

12 81 66 Epidotized green schist, white tale on
certain planes, some calcite in quartz
veins, small disseminated aggregates of
pyrite, few specks of chalcopyrite (?).

81 91 45 Green chlorite schist, narrow bands of
silicification, a l-inch white quartz vein
containing some calcite, some fine pyrite
near vein.

91 lol 31 Green chlorite schist, epidotized quartz
veins, 1 grain of chalcopyrite.

lol 111 45 Pale-green schist, central portion containing
sericite and minor pyrite.

111 BEary 52 Green chlorite schist with epidotized zones,
some of which contain abundant fine pyrite,
some veinlets of white quartz, which ~
generally contain a minor amount of calcite.

4033 - 19 -


Footage
From 2
451 462
461 671
671 691
691 704
704 155
155 7710
710 808
808 828
828 838
838 858
858 860.
860 882

4033

Percent
gore recovery

59

59

aT

86

81

87

100

100
96

Hole N-1 (Cont'd.)

Pale-green uralite schist; dark-green chlorite
is present in small lenticular masses, also
epidote; some argilleceous material is
present in the green schist; pyrite in very
minor amounts.

Uralite schist containing varying amounts of
epidote, somé in disseminations, lenses and
veinlets, numerous smill veinlets of quartz
and lesser calcite, some dark-green chlorite
also is present in certain zones; some
pyritic disseminations.

Urelite schist, chlorite, veinlets of calcite
and quartz, disseminations of pyrite
throughout.

Uralite schist rich in epidote, some chlorite,
veinlets of white quartz and associated
calcite, several silicified zones.

Uralite schist rich in epidote, numerous
small lenses or red hematite, quartz, and
calcite veinlets, some chlorite; hematite
occurs only from 79: to 733 feet.

Spotted uralite chlorite schist might be
porphyritic, minor amount of epidote,
small veinlets of quartz and calcite.

Urelite chlorite schist with considerable
epidote, porphyritic in appearance between
768 and 778 fect.

Epidotized amphybolite schist, thin layers
dark-green chlorite schist, mch introduced
quartz, also some veinlets of quartz and
calcite.

Chlorite schist, some epidotized, quartz and
calcite veinlets, some hematite.

Epidotized chlorite schist with paler green
intercalations of amphibolite schist,
quartz, epidote, 6-inch crushed zone shows
tremolite and quartz.

Uralite chlorite schist, vesicules of quartz,
some epidote.

Intensely epidotized and silicified schist
containing zones of chlorite and chlorite
amphibolite schist, vesicules of epidote
and quartz, pyrite is present only very
spersely as minute, small masses of white
quartz and calcite occur at irregular
intervals. This is the hanging wall of the
Newton copper vein.

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