WORK BY THE BUREAU OF MINES

Diamond-drilling operations by the Bureau of Mines were started June
1, 1940, and were completed December 6, 1940. During this 6-month period
10 holes were drilled from surface stations and 12 from underground
stations. The linear footage drilled is summarized below:

| AX hole ' EX hole | Lost hole (AX)| Total

Surface stations sess... | 1, 7008 i 3,017 80 4,099
Underground stations | 9 | 809 Ay 1,569
Total serccsreeeeee | et 3,626 1 5,668

The hole locations, cross sections through the holes, ond assays of
significant ore intersections are shown by figures 3, 4, 5, 6, and 7.
Descriptive logs of the holes are given on succeeding pages. The descriptions
of the rocks intersected by the holes are condensed from descriptions by
geologists Goddard and Pardee.

3881 - 10 -


Hole 1A-U (Cont'd.)

j Distance

Core

Core i Petrographic description

Footage | Core! drilled, jobtained, !recovery i Footage
From- To- size | feet feet | percent. i From= To~

1195 1201 Ex 6 a1" | 31.9 i 1195 | 1206 | Core about 1/2 recovered. Pale

1201 1206 * 5 wh" | 26.7 | i | buff marble (Hasmark) much
| | broken.

1206 1212 * 6 ato" 33 3 | 1206 1236 =| Pale-buff to yellowish-brown

L2 1218 ” 6 15” 23.6 Hasmark marble, medium-grained..

1218 1224 id 6 3°5t 56.9 A few fractures at different

leek 1230 " 6 15" 23.6 H angles carry thin films of

1230 1236 * 6 110" | 30.5 | Mn02. Core broken and mich of
| | | it missing.

1236 yeh. " 5 18" | 33.3 || 1236 12h1 | Similar rock as above - at 1,236
/ i feet, 1 inch cr more of cavern-
| i ous quartz with Mn0>.

12h1 12h6 " 5 o'l0" | 16.7 i} 1241 1246 {Core broken and largely missing;
| i | Remainder is cavernous quartz
| H | with considerable pyrite - ZnS

i i | and some PbS (Assay for Zn and
: Ag).

12h6 1250 ” 4 of10" | 20.8- 1246 1250 Pale buff to white Hasmark

j Marble, numerous fractures with
| i i j thin conts of Mm0,. Coré
H | | i broken and largely missing.

3881

-21-


Hole 1A-U (Cont'd.)

roota f « l Distance { Core | Core’ 4
—= ge = ore i drilled, obtained, | recovery || Footag Retrographic description
: feet ootage |
on es et ; percent From- | ____To-
a es A 3 /  5toM 100.0 | €2h | 63h |
irae Bo 3} Medium-grained gray marble
crossed by several thin
7 . peewing buff core. At eo
. . ows some black (MnO,
at on |) 2 320 5.0 || 63 71976" | nonome Fink (cos) ont) ee
x # " 3 ies 10.0 Mostly bare medium grained marble,
" some
5 20" 8 gray. All more or les:
& |S [ils | is Be | Taek Satcalhtas
1 . : °
Ble |r | we BS Bears,
2 E " 3 org | 259 eae yuck brown iron oxide.
on a ee 33", | 0 CSS'~697" Some quarte and Mades
s 2 3 ar 36:7 95'-697" Some quartz and Mn0o.
689 69h o | 2 Lor 20.0 |
éoh 609 . 5 are hc?
699 70% o | 3 ioe | 33
639 Lis . 5 lia® [ 23 3
1b me ; 5 ater | 43 3
Tus 719 " 3 an 36 2
nm ne " 5 2to" | 56.17
eh 8 . ? 1'o" | 20.0 719°6" 826" L
ra ; i orem, | es ght but? Basmace marble core.
73h 73h w log om" | 22.9 Inches of 0, forlowes 3
739 Bg a 15 om | a8 Inches of able ewrlly
The The " 3 otgt | 20.0 sta’ ed vith Unonite.
e ta : d oie a st ined with limonite. Rock
750 teas ax 3 org” | 25 ‘0 soniye =
} 6 omewhat iron-sti
15 7600 ” 2 atrem | 30.0 | “
3881 ~ _ | |
7~.1t


Hole 1-S (Cont'd.)

fl Distance } Core : Core i Petrographic description
Footage ; Core jdrilled, | obtained, | recovery, | Footage A
From; To- |L_size feet | feet |_percent || From- To-
wm | 16), ak | 5 yrqe 9.7 | 12 + 142 | Coarse white Jefferson-local
116 121 i” 5 1'8% 33.3 ! occurances of limonite-stained
21 126 to 5 3°10" 76.7 fractures. At 128'6" a streak
126 Blt 8 5 ego 91.7 1 of porous limonitic material.
BL 136 \ * 5 rg 95.0 ;
136 ua | 5 4ge B3 H
wa 147 " 6 o'5" 6.9 wa | ws7 Cavity-4 inch core with Mn0Oo.
spots.
147 154 " 7 Ato" 69.0 147 19 | Brecciated Jefferson with spots
| ! of Mn05.
i 19 i 151'6"| Chocolate-brown marble.
; 1516" | 153 Soft brown Mn0s (wad) appears to
lie parallel to bedding and 45
{ i degrees to core.
. 153 154 Dark-brown marble.
“154 156 Ex 2 1he 66.7 154 | 156 Begin 7/8 inch core. White and
a . i brown Jefferson marble.
156 158 | " 2 2'3" 100.0 156 161 White Jefferson. Locally
H brecciated; some brown wad.
161 166 1° 5 tio 96.7 161 166 White Jefferson, coarse-grained,
j . | wad-stained fractures.
166 171 io. 5 ren 90.0 166 | 171 Medium-grained white Jefferson
marble.
171 176 " 5 ory" 11.7 171 176 Gray Jefferson - 6 inches of
core.
176 183 " T 6" 64.3 176 186 Gray to white Jefferson, locally
183 185-1/2 | * 2-1/2 1'10" 73.3 friable and limonite-stained.
185-1/2 , 186 "| 9-1/2 ore" 100.0
186 | 187 [on pa oi" 91.7 186 i 187 Gouge

3881 - 26 -


The Philipsburg district is in and around an embayment on the west
contact of the Philipsburg batholith (fig. 1). The batholith is granodiorite
of early Tertiary age; its outcrop is about 10 miles long from east to west
and about 6 miles wide from north to south. The rocks that have been
intruded by the batholith constitute a thick sedimentary series whose age
ranges from pre-Cambrian to upper Cretaceous.

A major fault, known as the Philipsburg Overthrust, crops out about
2-1/% miles west of the batholith (fig. 1). This fault strikes nearly
north-south and dips about 45° west, Pre-Cambrian sedimentaries west of
the fault have overridden Paleozoic sedimentaries east of the fault. The
Paleozoic sedimentaries between the fault and the batholith have been
crumpled into synclines and anticlines whose axes strike north-south and
plunge gently north.

Most of the Philipsburg mining district is in an anticline whose east
flank and southern end are truncated by the batholith; part of the district
is in the batholith within 1 mile east of the contact.

The Philipsburg anticline generally is symmetrical, except on the
southern end of the east flank, where the beds appear to have been thinned
and steepened by compression against the batholith. The top of the fold
is rounded; the flanks dip 30° to 70°, Throughout most of the district the
folds plunge north at about 20°; near the southern end, however, the plunge
steepens slightly against the batholith.

The sedimentary rocks that comprise the Philipsburg anticline within
the mining district are almost entirely of Paleozoic age; their age ranges
from Cambrian to Carboniferous, Thin-bedded, impure quartzites of the pre-
Cambrian Spokane formation crop out at the southern end of the district, but
no ore deposits have been found jin them (fig. 2).

The Paleozoic formations are described briefly below. The descriptions
are arranged successively, from lowest to highest.

1. Flathead quartzite: Cambrian - about 150 feet thick. Composed
of fine-grained, impure quartzite and thin-bedded, dark, shaly
quartzite. The base is composed of 25 feet of coarse-grained,
white quartzite,

2. Silver Hill formation: Cambrian - about 300 feet thick. Chiefly
thin-bedded, nearly pure limestone alternating with thinner,
slightly wavy layers of brown, siliceous shale,

3. Hasmark formations Cambrian - 800 to 1,000 feet thick. Medium- to
Pine-grained, dolomitic limestone locally metamorphosed to medium-
grained white marble.

4, Red Lion formations Cambrian - 225 to 300 feet thick. Chiefly

thin-bedded, shaly limestone with wavy, discontinuous bands of
yellowish shale.

3881 -6-


Hole 7-S (Cont'd.)

______ Footage | _ |Distance | Core 7
From- |. To- Core | drilled, | obt } Core ji
i siz ? | ained, : re: Pet:
au | 250 or _ hee 4 percent. —— ae Sescription
250 | ase " per 88 Tei) e57 |
2 H 2 i i | Fine-grained
Bay | oop , 5 | ae a 2 i | cavities 24s to pigestone with
258 263 8 1 | orn | 1.6 .
263 | 268 0 | 5 16" 33 | 257 263 |
| 3 18" 33. i ; Buff, sugary limestone
ae om =| | 6 3 263 | «268; Coarsely °
H i i e.
cr ee ee _ Site Ceptnnie Nee aise
285 5 oO | ; Coarsel,
290 | 298 ; 0 | 5 oe To.0 | 280 | 337 | r arsely crystalline gray Line-
2 i 2 i 5 7 | I i ine-grain
300 | -_ 4 5 | rem 90.0 | | stone. ed bluish-gray lime-
305 310 nf 5 yg on.6 i !
go ne es ge | |
es pe 5B nr | gts
re ee ee | BS |
ae ee par} Be
: 7 nei " = | i
i 5 : i 7 | 37-5 | i |
a a ee
, | 5 | one | 3 i337) ale |
guy ge p OT 88 (ie |b | Fine-grained bluden-gra .
3203 i 5 1 ote | i i | Fine-grained bluish-
357! 33 i" 5 | fae | 46.7 | shy) 357 stone. ish-gray ‘Lime-
360 | 36h if 0? | ott ae | \ r ; Buff limestone.
34 | 368 ont i ; ot | ui | 357 36h | Gray 14
38 | aR be tL | apts - | ; Gray Limestone with quartz.
377 a Pry an + 360 :
377 1 5 no 83 | _ | Bluish-gray fine- ;
388: 32 3 Orso i 83 \ | ° Stones y fine-grained lime-
2 ! 3 !
i
- 5h


Hole 2-S (Cont'd.)

; Distance | Core i Core Petrographic description
Footage Core ' drilled, | obtained, recovery, | Footage i
From j__To- size feet | feet percent || From, To- !
3ll | 37 Ex | 6 , ore" 11.2 |} 311 =| 327 | Mostly quartz with disseminated
i | i fine sulfides..-
317. «| «319 Ax | 2 ; 2t0% | 100.0 | 317 | 330 | Mostly gray, fine-grained mrble,
319 | 32h | x | 5 ; tet 83.3 | | |  in@istinctly banded about 80
32h | 330 ; * 6 ' 376" 58.3 | \ degrees to core axis - last 5
| | | feet, buff, fine-grained, sandy
| i i limestone.
330 «| 335 Ax | 5 1 510" ioo.0 | 330 | 383 | Gray, fine-grained limestone.
335 i 337 i Ex 2 ' ato 100.0 } i i Dark-gray bands - occasional
337 | 3he ; ° 5 1 5to" 100.0 i | | fractures 45 degrees to 50
320} 3k7 jo" 5 | 519" j 100.0 |, f degrees to core axis. Bedding
3h7 i 352 " 5 ; 5to" 100.0 jj i stands. from right angles to 75
352 | 358 jo" 6 15 1 B46 ft | degrees to core.
358 | 380 LOS | 5t0" 100.0 |! |
363 | 368 "5 i ato" | 56.7 | i
368 «| «372 #1 § 1 3 1 89.6 |
372,374 " |e ' 2to" =| 100.0 !
37 379 "15 1 510" | 200.0 :
379 | 383 "otk | htoTM 100.0 | ‘
383 ; 388 » | 5 ; 3'10" 76.7 || 383 | hel | Similar to last except crossed by
388 | 301 i" fF 3 | 28" 88.9 | | | several broken, gougy zones.
391 1 396 rn) | 4t10" 96.7 \ H | Occasional fractures line, with
396 =| shor 8 | 5 | yea 81.7 | | | soft greenish mineral (chlorite).
hor = -Ko6 i" | 5 25" 48.3 | ! |
ho6 ts Way foe 1 5 i 510" | jo0o.0 } ! |
yay} ka ij" | 3 / 3t0" | 100.0 |: :
yah} 416 |" | 2 , 2t0" | 100.0 |, i
416 | ker ” 5 : 5to# 100.0 } i :
yor, he ed | 5 1 5to# 100.0 j; 422 i 433 | Similar to last - core mch
426 | 3a | "15 | 5t0" 100.0 |j i broken from 4321-433".
432 | 433 " 2 2'07 =| 100.0 © ‘ :
3881 - - 36 -


Hole 2-S (Cont'd.)

{ | Distance | Core ! Core | Petrographic description
Footage Core; drilled, ; obtained, | recovery, | Footage
From- | To- i size) feet t feet percent 4 From- ij To-
ha 45 Axi 4 Brkt 83 4 dL 68 | Grayish-white marble with occa-
45 Sl; 6 5'0” 83.3 | | sional fractures coated with
51 57 ; oo" 6 378" 61.1 | limonite stains. Broken zones
5T ics} " 6 316" 58.3 j showing a little iron stain at
8B 68 . " 5 kyon | 95.0 | 5h '9" and from 62 to 63 feet.
3) B » | 5 ktg# 95.0 68 97 | Light-gray to buff marble, more
B Tw yf 4 318" 91.6 or less broken. In places,
77 82 " 5 ys7e 91.6 grayish banding about 70
82 87 " 5 310" 76.7 degrees to the core axis. At
74 to 76: feet, rock is friable
and seamed with limonite.
87 92 " 5 4tgn 93.3 At 68'6", 3 inches broken and
gougy with a little Mn0o.
92 oT " 5 3hn 66.7 At 82'2", to 82'S", quartz with
mich limonite. At 90’ to 97",
i broken somewhat gougy. zone.
oT 102 " 5 3'o” 60.0 oT 159 Light-gray to pale-buff marble,
102 107 ” a5 yy 86.7 locally fractured and stained
107 13 " 6 Ara "81.9 i with limonite. Friable in
113 118 | ” 5 2*10" 56.7 i Places. At 132'to 135’, breccia
118 1233 , 5 Ato" 80.0 i with considerable limonite and
123 w | 5 2tg" 55.0 | recrystallized calcite. Cougy
128 133 ; * 5 eri" 58.3 | at 135"; 1376" to 139°,
133 138 Bom gS hiton .. 80.0 brecciated with limonite and a
138 nian i os 6 yrs 68.0 little Mn0p. 157' to 159!
wy) 150 } oo" 6 371" 65.3 breccia with limonite.
150 156 i : 6 en" 34.7
156 i 157-1/2 | 1-1/2 15 oh.5 |
157-1/2 | 16 oe 5-1/2 kton 86.4 1159 166 White to grayish marble, banded
163 1 168 rs ren g0.0 | at 70 degrees to core axis.
3881 - 34 -


Hole 3-S (Cont'd.)

Distance; Core i Core Petrographic description
___ Footage Core | drilied,! obtained, | recovery, Footage
From- To- _|_ size feet feet i_ percent From- To-
aks 2h6 Ex 1 org" 15.0 2h5 2h6 Fine, thin-bedded, gray marble.
Core split into thin segments on
bedding planes at right angles
| to core. A little fine pyrite.
2h6 251 " 5 17" 31.6 Oh6 251 Yellowish, medium-grained marble-
friable. Core broken.
251 256 " 5 316" 70.0 251 280 Light-gray, fine-grained marble.
256 259 " 3 eta" 72.2 Bedding seams and fractures at
259 264 : 5 ru? 61.7 different angles carry thin
1
ae 2m " 8 2m 8 3 films of chlorite.
275 280 " 5 216" | 50.0
280 285 * 5 25" 48.3 280 285 Light-gray granite like 195'-2hk!
. section above. Dark minerals
largely altered to chlorite.
| Fractures parallel to core.
i Coated with chlorite.
285 290 " 5 1tg" | 35.0 285 318 Medium-grained, gray marble.
290 295 " 5 218" 53.3 Locally core is mch broken and
295 300 " 5 o*10" 16.7 partly missing. A 1-inch,
300 305 "15 nai! 38.3 black, shaly band with gouge at
305 308 * ) 3 ito" | 61.1 307 feet. Black shale (horn-
308 323 " 5 no i 109.0 stone) at 31616".
313 318 * 5 "10" | 96.7
318 323 " 5 31" 61.7 318 338 Core badly broken. Occasional
323 328 " 5 1to" 20.0 pyrite grains. At 322'-28'
328 333 " 5 ar" 41.7 mich chlorite and a litlle
333 338 " 5 1tq" 31.6 pink carbonate.
338 343 " 5 5t0" 100.0 338 350 Fine gray mrble. Bedding planes
343 348 " 5 3he 66.7 | and local fractures coated with
: Hy chlorite.
348 353 " 5 | 5to" | 100.0 350 350'6" {Irregular veinlets of pink
: ‘carbonate.



Hole 4-S (Cont'd.)

Distance , Core ; Core = || Petrographic description
Footage Core | drilled, ‘obtained, | recovery, || Footage 1
From- | _To- size feet | feet___;_percent From-__| To-
180 185 Ex 5 uty" | 32.6 18016" 184 Core mostly missing (contact
j zone?) .
185 190 ” 5 | oma" | 18.3 || 18h 212 Light-gray, medium-grained
Be | 39 , 2 | ie i e3 | granite and aplite. Broken
i . zone 199 to 210 feet.
200 205 , 5 | 18" 3343
205 210 " 5 ike : 26.7 |
210 215 5 ; 2'3! i 45.0 {I
215 220 " 5 | 3h" | 61.7 || 212 220 Pale yellowish-gray, fine-grained
' j | marble. Locally somewhat
| i 1 cavernous.
220 225 |" 5 | ate : 46.7 220 | 235 Bluish to brownish-gray, fine-
225 230 " 5 ' 215" | | 8 3 | grained marble.
230 235 5 ; ofo" § 16.7 .
235 2ho " 5 ; org" » 15.0 235 2ho Mostly broken and gougy. Largely
| | missing.
eho 2h5 ” 5 | 1'0" | 20.0 eho i hs Yellowish medium-grained marble,
H i | core partly missing.
ahs 250 ! " 5 ofl" i 18.30 |) ahs i 250'6" | Light-gray granite. Core broken
| . : and largely missing.
250 255 io" 5 | 218" | 53.3 250°6" 265 Gray to dark-gray, fine-grained,
29 i 260 H " 5 | 218" : 33.43 : H impure limestone-soft in places.
265 | 5 | 2tl0  D66T : .
265 | 270 io“ 5 i 15" » 28.3 265 | 275 Siliceous fine-grained limestone.
270 ) 275 oo i 5 2g 25.0 | ' i Greenish to brownish gray. At
! i ‘ \ | : i | | 266 to 267 feet, quartz showing
i | | | : ' fine disseminated sulfides
| i | : : \ (assay Ag Zn). At 273 to: 275
! i t j {I feet, dark-gray quartz with
| i i ' t fine, disseminated pyrite and
H : : {| i some ZnS. (assay Ag Zn).
275 1 280 ' "o's 1 of" ° 18.3 k 275 | 276 'Fine-grained quartz with dissem-
oO !

3881

| inated pyrite and ZnS?


Hole 1-S (Cont'd.)

Petrographic description

i ' Distance Core | Core ij
Footage i Core| drilled, | obtained, | recovery, iH Footage
From To- size: feet feet percent |, From- To-
801 806 Ex | 5 yr" 98.3 || Similar marble with to
806 812 " 6 su" 88.8 greenish-gray bande about 60°
812 816 " 4 ye 100.0 || to core. Locally crossed by
i fractures and thin greenish-
| gray seams. .
816 821 " 5 ' 100.0 816 873'6"; Light-gray, fine- to medium-
821 827 " 6 se 88.8 grained marble with browish
827 832 " 5 5° 100.0 siliceous laminae, mostly less
832 837 " 5 5° 100.0 than 1/2 inch thick, that in
837 8he " 5 5° 100.0 | places composes as mich as 50%
8h2 847 " 5 5? 100.0 of the core. In places these
84-7 852 " 5 5 100.0 alternate with thin gray
852 857 " 5 5! 100.0 laminae. Locally, grains of
857 862 " 5 5? 100.0 brown silicious mineral (garnet)
862 867 " 5 5st. 100.0 form 50% of mass.
867 871 " 4 ate" @.5 |
871 876 " 5 5° 100.0 H
876 881 " 5 5! 100.0 | 8736" 887 Bluish-gray marble with darker-
881 887 " 6 Atrio" 80.5 gray rather indistinct laminae.
4 Locally crossed by seams of
| greenish-gray (chlorite?)
887 892 | # 5 5t 100.0 || 887 902 - | Similar marble, locally broken
892 897 " 5 213" 45.0 |} and gougy.
897 902 " 5 193" 25.0 |!
902 907 " 5 1'" 38.3 ; 902 OT Rather abrupt change to pale buff
marble showing a few MnO,
1 dendrites (top of Hasmark.)
902 gl2 " 5 38" B33 | 907 gle Buff to grayish-blue mrble more
i . or less fractured.
912 915 i 1 3 2to" 91.6 1 912 ou Broken and gougy, with consider-
q ! i able disseminated pyrite.
3881 - 32-




Govordinates: 8918N, 10,7725 Depth: 278 feet
lole No: 2-1 Bearing: N.
Dip: 78 degrees
i i Distance : Core _ Core fi Eetroaraphic description
Footage | Core; drilled, ; obtained, | recovery, Footnae—
From To- size| feet feet percent + From-
+ ++ ,
(0) 5 Ax 5 1134 25.0 |} fo) i "3G i Light-gray to pale-yellow
5 10 , 5 bro® 80.0 i i coarsley-grained Hasmark
10 b : 5 Hl ur’ 81.7 | : | marble. A few fractures 45
15 20 5 | 3°5' i 68.3 |! H : degrees to core. Just about 5
20 25 ” 5 en 41.7 || | feet a 6-inch or larger zone of
25 30 " 5 2'10" 56.7 | i friable rock showing consider-
30 38 " ° 113" 23 | | able Fe oxides and a little
32 3 1'9 3.8 | i ' Mn05 +
360 | da " 5 | ata" 43.3 |) | i 2
a 46 ” 5 1 3" 61.7 |; j :
46 51 "1 5 210" 56.7 |) |
51 56 " 5 eat" 58.3 !
56 61 " 5 ari” 58.3 |! 56 90 | Light-gray fine-grained Hasmark
61 66 ” 5 ryt 81.7 |; H with indistinct graylaminae 45
6 n : 2 3 & ° ! i degrees to core (bedding).
50. : :
1 80 7” 5 30" 60.0 jf: | |
80 85 i 5 113" 25.9 |} | |
85 90 ” 5 ; ltot 20.0 |} | |
90 95. | 5 | 10" | 36.7 {i 90 95 | Friable Hasmark brown with dust
| i H of Fe and Mn oxides.
95 100 " 5 1'7" 31.6 I; 95 | ng | Light buff to bluish-gray marble.
100 =| 10k * i, 310" 75.0 |) | Iocal fractures with films of
i 1 { {
ie 109 , 3 are a3 } : M03. Core mich broken.
m2 02«2§ «6st i, i t
mué | 19 § * | 3 | are" | 8343 Ii i i
H \ :


Hole 7-8 (Cont '4.)

‘Di
So Core | i aealies : otto a Core :
i t 2 e ik
oT Ton size | feet | feet vvoreent 4 ee description
ior} 103 Ex | ; om” | 2 4 From Tow
13 020 i| 2 Loto | 08 | 97 +t 105 |
ws | uo fo | 2 1 ort | p2 ‘| : i MnO, -
0 0} msl} li 3 i ato" | 38 | f i
i | | 56.7 il i |
: i 5 1 to" i 2 4 105 i 110
115 ' a0 wl | ‘ 3-3 i] 110 | in Mn-stained limestone
wo | 5 " 2 ote | yi. } 5 Fine-grained gray Linesto
125 3230 ” 3 H 1'7" i 33.3 i! 115 1 25 Mn-stained limestone and ne
33 ' 25 " 2 \ 113" : 3s i i Fine-grained buff me and quartz.
74 1 ot7# : ° ub j .
wo | ae ‘ 5 i one , We | !
us! io | os 5 , age | 8.30 | i
150 155 hom | 3 ees 33.30 Ii 1 |
Bm 5 Poa: 20.0 H
ee ne 36.3 |
165 » X70 | os i 29 i o3gtu a 0 i i }
Wo} «15 no 5 i eae |
175 | 180 mB ane 11.6 || |
180 i 185 | 5 | oaty : 21.7 ff i
185 | 190 — 5 1 pee | 31.6 i |
iso! (195 ios 5 + Saye | the i
195 i 200 | 5 i oles | 6.7 || |
200 1 205 t 3 1 ort. | 38.3 i H
205 ' 910 ” a i ofa" | n6 |
a1 5 | 38.3 |
215 FA F orgt, | y Ht i
215 + 220 Log 5 Saige | 5.0 || '
220 —_ —_ 5 Coe 20.0 | } |
225 i i 5 i Btag# | 31.6 =| : |
| 230 oo | 10 | 56.7 | t {
230 | 235 tog 5 1 atgt. H a fT i
235 |. eho " 3 Mo atgh | 35.0 i
2hio 2h5 n i 2 item 2 3 a !
> Sith 350! | |

3881
~ 53 -


INVESTIGATION OF MANGANESE DEPOSITS IN THE PHILIPSBURG

MINING DISTRICT, GRANITE COUNTY, MONT.

by
S. H. Lorain’

CONTENTS

Introduction and SUMMATY ..c cece rece cc cn ccc ceccccencsecee
Acknowledgments ...cececcecceccecceseccceceees
Location and transportation ........
Property and ownership .....cceceecveee
History and production ........
Physical features and climate .
Description of deposits .......
General geology .

Ore deposits ... sees
General ....
Zinc-lead-silver veins ....

Manganese deposits ..........

ThE OTE weceececceccececececs
Work by the Bureau of Mines .....

TLLUSTRATIONS

1. Location of Philipsburg mining district, Granite
County, Mont, cecccsccccccccccccccccecvcscececeres
2. Geologic map of the western part of the Philipsburg
district, Granite County, Mont. ...sccececcceseeee
3. Mine workings in part of the Philipsburg mining
district, showing location of Bureau of Mines
Grill HOLES co ceececccccccccscvcccsccevcccccsecece
4, Plan and vertical section through drill hole 1AU ...
5. Plan and vertical section through hole 2U, showing
300 and 500 levels, Scratch Awl mine ......eeeeeee
6. Plan and vertical section through drill holes 1s,
2S, 3S, 4S, and 5S wecccccccccececececccceccceeees
7. Plan and vertical section through drill holes 6s,
TS, 9S, and LOS .oeseceseccccvccccccccccceccceeees

E
oO

SCO OANA EE EWWNDP

Bb

Follows
page

2

lo
10

10

10

1/ Chief, Albany Branch, Mining Division, Bureau of Mines.

Report of Investigations 4723


Hole 9-8 (Cont 'd.)

' Distance Cc
_____ Footage | i ore i Core i
a te
+— H ‘ee |_ percent Hom “a |
102 ee a te
i jp dont 36.7 | 102 | «9107s, Liight~b
107 109 "1 op | oto" | i | “MA inch) Mao, at 102 fect.
109 ak EOS tooo | 41.6 || 107 '  y09 | putt to nch) Mn0, at 102 feet.
uh | | H fe) 80.0 || 109 H lll | Bluish unten ery limestone.
| 9 oot i . Hy i ' “gray stone.
ns fw fl | 3 io" | 20.0 jj ak | ies | Meoecoteine? linens
‘ | | ; ou 36.3 | i Oo"stained limestone - brecci-
30 35 "1 6 4 atom 1 45,8 es | | Gwen 18 and Ihe
135 ' iho ios | 5 i 311". 67 ij : 165 | Buff limestone. °
ts Bight i
Us ' 450 pi 8 ' 23 oo 45.0 i !
150 155 no} 5 : ONT / 6 ! i
155 160 ols org" FBO ! i
io ws i ot Ss or" 18.3 !
Q2 15.0
Co-ordinates: 11,951N, 11,159. Hole 10-§
Elevation at collar: 5,8iH1 feet Depth:
Dip: 33 degrees Perens re geet
: od le west
31 en nce “0 |
' | i Hi s
38 a ; #6; Granite.
| ; 10 foam ! | !
48 53 a | : 15.8 il H i
i 1 5 i ott H i i
| H | 9 | 15.0 7 48 53 CO! ;
53 fom | i | | Gray limestone - little Mndg
58 | 1 5 ato" =| 200 53 j | stain.
! i i oe t i} i
58 @ i" 1 5 | sion | i | | ene 2 age ee
8 70 nf , 2330 9 BO, se ee
70 ie j 7 | ai" | 27 i 4 6 | 3 i grey limestone.
75 fm 1" 1k | ono | BoB k ! Limestone ~ badly broken.
19 H i H 20.8 ji |
oe "15 fat" 1 350 | |
i

2981
- 56-


Hole 8A-S

Co-ordinates: 11,613N., 12,203E. Depth: 140 feet
Elevation at collar: 5,810 feet Bearing: WN 80° W.
Dip: _ 62 degrees
i ; Distance! Core | ik Petrographic description
‘cotage | Core | drilled, . obtained, recovery, i Footage .
_From-: To- | size feet 4 feet “percent {i From- | _‘To- |
te) 82 | Ax ; 82 | \ fe) | 82 | Granite.
82 85 Ex | 3 + ato | 66.7 tt 82 | 96 | Buff limestone.
85 99 " ) 5 | ato* | how |
90 96 “oy 6 | 3'10" | 63.9 | 1
96 101 pom tos , oat! 51.6 96 101 i Buff limestone - occasional frac-
i | i i 1 ‘tures lined with soft greenish
“ : i ! | ! mineral - chlorite.
101 106 | a) 16" | 30.0 | 101 106 , Coarsely crystalline buff lime-
106 m of 8 is 316" | 0.0] 106 yi_| putt limstnee
m | m6} 5 | ats” 48.33 |
116 il a) 1 28" 33330
1 126 " ; 5 + otgt ; 15.0 |} den 126 Buff limestone - some mscovite
i i | - 4 | | and considerable gouge.
126 131 ns) 0'8" ‘ 13.3.0! 126 140 =~, Finely crystalline buff lime-
BL B Ft ! ok | otto" | 20.8 | | "stone.
135 140 ne! 1283" 85.0 !
Hole _9-S
Co-ordinates: 12,054N., 11,2195. Depth: 165 feet
Elevation at collar: 5,830 feet Bearing: Due west
Dip: 58 degrees
o | 9 | fi 79 i | | 0 i 61 : Granite.
19 81 | Ex 2 i i { i
81 8 | NOS uy" | 31.6 tt 1 Buff limestone - some Mn0p stain.
86 et | 6 | ater | dns | |
92 oT ;oe tos i193" | 25.0 i 92 | oT «=; Buff pimestone - bedding planes
{ t I | at 45 degrees to core.
7 102 | # fos tts" | 28.3 | 97 | 102 { Same as above but with Mn0o stain.
1/ Core size: 0 to 57 feet, Ax; 57 to 79 feet, Ex.
3881 - 55°




Hole 1A-U (Cont'd.)

Footage —

From-

Core i drilled,

size |

Distance !

feet

Core

| obtained,

feet

Core

; recovery

percent

i

Petrographic description

iL From~

a Footage |

To-

{

kon

oh

496

501

505

309

514

519
521

3881

|

a

496

501

305

509

514

519

521
525

=,
|
|
|

Ax

”

"

i}

3

u

1"

11"

115"

3t5”

2'e"

amen

2tg"

ay
32”

36.1

95.8

28.3

85.4

66.7

46.7
55 200

5h 2
19.2

-15-

| 49087"

koto

496

doktor

496

500'7"

50k"

509

5u:

a19

>)

+

| First 6 inches mostly fine-

grained quartz, replacing

limestone; some pyrite; next 10

inches largely pink MnCo3 with

fine-grained dark patches

(sulfides). Last 3 inches

brownish, fine-grained Hasmark.

| Hasmark breccia cemented with vein
quartz and white to pale-pink
carbonate (some MnCo3) » Rock
is locally cavernous.

White Hasmark with indistinct gray
bands (bedding) 45 degrees to
core. Locally brecciated ‘and
cemented with quartz.

Hasmark fractured and crossed by
dark seams containing fine
Pyrite parallel to core. Last
inch shows some pink carbonate.

Vein quartz banded parallél to
core with dark seams showing
pyrite ZnS & PbS at 506 feet,
the sulfides fairly abundant.
Last 2 inches gray gouge. .

Similar to last except more or
less broken and showing smaller

| amounts of sulfides.

; Mostly quartz with some dissemin-

ated fine sulfides.

! Light-gray quartz and carbonate;

| some pale pink, some bands -

| parallel to core.showing fine

| sulfides.



Se TN aM
‘630,778 IS

-
rian
|__ ono

‘TRUE FissuRE
286 WINZE

ml

HORSESHOE

WWRTLE SHAFT
MYRTLE 300

i” om
Se pes >
> xX \\ /
ee BRYAN] SHAFT
Fcc. WO.BRYANT \
e sexo a sary oobenseo)
= sear \ ROCK Se sey, Be
are Baca SAF wan
- CE Na
Se Yoou|2—
Figure 3. - Part of Philipsburg district, showing mine

workings and drill-hole locations.


00»

Percent
=| “ae
y Limestone Serenite zor eset 73.8
5 es
Nat Tunnel | =
es Semple [CenaTh Pereent
Tunnel intervat__|/ “feet [We Fe
a a
10800. a
== _—
i | 320 [oo
3—fioz0-tos0 a"
+ -figze foes SECTION A-A'
‘sa0=ses | 3 = _
10600" — . asasas fe | SECTION B-8'
8 “ : ~ — «2004 72
H 8g Hy
3900 ee 00
Seale in et
_ Samos] egth Percent Or ber Tor
seoe DOM 38, PLAN invervot__| teat [ia [PT iso [Za aw aa.
El, $740 Hooy Horse Tunnel 2 = 320-08 [6.10
t= 20-[0-08 1-40
135 0-10.08] 0.65
“Sanpete aeeear 3s CMEXIIERE
intervet_| teat [mT | il ia ide 0-92 fr 30
zrs-27e {2 f — ff — 0 [== | se foorlss
sere {ft thes T= Teor toesre ss
gso=282 | 2 135.8 toon] — aoe ae
a1 t—1— 137 Toosto:
Cocore Sesiudge \
sor—_
wor —
<
000 —
SECTION EE" SECTION C-C'
— s100' —

Figure 6. - Plan and vertical sections through drill holes IS, 28, 35, 4S, and 5S.



9600 | 9600
Myrtle Shaft
el. Saaz"
Clift Shaft Grosscut |
sro 1 3700
il Bryant Shaft Horton Shaft
\\ 15937! —$45— _ftogton Shot
iH
seql<-|| —-— pv. | 0
ame eens 5 3300 3600 9700 3000 3900 70000 7100 73200
Ve.
Vie PLAN
100° o too"
SS
SCALE IN FEET
600°

ton Shaft
JECTED

,
a

2

800
SAMPLES Nos. 21-36 yy
ome
ae ae ee a ea
WO t= 00S 05
y 5.0 5.0 = U3 0. )425
won go SO TO 050025 Te sa"
> i ROR
DE re
2 ot frou 20:70
- - 0,03 28.40
= - 0.6 ‘4.20
9.80 - - 0.87
SAMPLES Nos. 1-20 foe : - 0.58 0.60 — s300'
Percent, - = 2B 0.02 12.25
Yow Re Zoo:
~ 11.92 - = -
d Pr a net cn O20
3 So0 of fot mS Door See
3 Zo 5 : = oo® x
se" - 50 ~ - - r i ay 200"
5 5.0 = - - 0.02 oO
6 Soo =e - = ool 0 ly
3 Bor ot tlt ro: SECTION
9 5.00 = - - - rT °
20 ze - - - - tr TM
it mol Dt a
#100" 12 2.0 = - : = tr Tr / soe’
3 3.0 13. 0.9L 15.9 0.05, 0.01 0.10
ly 2.0 11. - 28.1 0.05 tr tr
ref 50 2S ho
% fo 00200 2 2 lf Ro
wv Oo = - - 0,12 0.18 tr 0.91
1B so 5 - Z 0108 «0.05 tr osha 1250"
s000'~ 19 So > : in 000"
20 60 = - - - - tr Tr

Figure 4. - Plan and vertical section through drill hole | AU.



Hole 1A-U (Cont'd.)

j Distance ! Core ; Core ‘i Petrographic description
Footage Core | drilled, ! obtained,: recovery | Footage
From To- size| feet 4 feet | percent | From- | _‘To-
525 | 529 AX 4 j 193" | 31.2 | 525 | 529 Bands turn to 45 degrees to core.
| i j Sulfides are mostly pyrites.
529 53h " }o5 2" | 4.7 529 || 530—| Broken core chiefly white and
| i Pink carbonate. Banding
| | disappears.
534 539 . 5 1'o¥ =: 20.0 | 530 539 First 2 inches brownish marble.
i Next 6 inches white carbonate
| 1 rather heavy in fine pyrite
i i and 2nS. To 539 feet white
i Hasmark slightly stained yellow
and fractured in places.
539 Su " 5 193" | 25.0 539 Shh White Hasmark locally fractured
| i and stained yellow (limonite?).
Sh Sho " 5 3°" B3 | Sly é2h Medium-grained light-yellowish
. t Hasmark.
BAO 554 " 5 10" 20.0 fl | Marble core is mostly broken to
554 559 " 5 he 26.7 pieces 2 inches or less in
length.
559 564 , 5 1e 26.7 At about 563'-2" of quartz with
fine sulfides.
56h 569 " 5 370" 60.0 | At about 567'-569' quartz with
i fine sphalerite.
569 57 ” 5 1 26.7 | At about 573'-1" quartz and fine
sulfides.
574 579 " 5 1h" 26.7 | At about 5827-58)! Numerous
579 58h " 5 3'o" | 60.0 i fractures with iron stain and 1
: seam pyrite.
58h ; 589 " 5 15" | 28,3 At about 588'6"-589' quite
589 504 * 5 213% 45.0 locally rich in sphalerite.
594 599 "5 310” 60.0 At about 614'-619' fractured,
39 % , 5 aime 16.7 | friable, and slightly iron
0 2 Be) | stained.
609 ak ” 3 3t0" teat
614 619 " 5 1'a" 23.3
619 eek / 5 110" 36.7 I

-16-


Manganese deposits

Rhodochrosite is an important primary constituent of virtually all
ore deposits in the district. It is abundant in all vein deposits, where
it is generally considered to be a gangue mineral and consequently is
discarded; some veins of nearly pure rhodochrosite have been mined for
manganese, however. Large amounts of rhodochrosite occur also as low-grade
disseminations in limestone beds adjacent to faults between the sedimentary
formations. Because the known disseminated rhodochrosite deposits seldom
contain more than a small percentage of manganese, they have been mined
only in a few places where relatively high-grade ore bodies have been found.
However, inasmuch as all of the manganese oxide deposits of the district are
believed to have been formed by oxidation in situ of primary rhodochrosite
deposits, it is inferred that larger and richer rhodochrosite replacement
deposits may be found by deeper exploration.

Nearly all of the past production of manganese has been obtained from
deposits of manganese oxide, which occur as irregular replacements in
Hasmark limestone adjacent to east-west fissures or as replacement deposits
in Hasmark or Jefferson limestmme adjacent to the granodiorite contact.
Usually the largest ore bodies are near the intersection of east-west
fissures with bedding-plane faults. Apparently their size depends on the
degree of brecciation of the limestone. The southeastern part of the
anticline, where the sedimentary rocks appear to have been crushed against
the granodiorite, has been the most productive part of the district.

Manganese oxide deposits along limestmme beds have been worked at the
Headlight mine, where the manganese is in the Red Lion formation adjacent
to the Red Lion-Maywood contact, and at the West Algonquin and Bernard
mines, where the manganese is in limestone members of the Silver Hill
formation. At the Headlight mine and at the West Algonquin and Bernard
mines the manganese is in the vicinity of well-defined east-west fractures
but is localized along favorable limestcne beds.

The replacement deposits of manganese in Hasmark or Jefferson limestone
generally are roughly pod-shaped. The dimensions of most deposits of this
type that have been mined ranged from 50 to 250 feet long, by 30 to 100 feet
thick, by 10 to 125 feet deep. Individual lenses seldom have produced as
much as 50,000 to 100,000 tons each.

The tabular bodies of manganese ore in the Headlight mine have been
developed throughout a strike length of about 800 feet and a dip length
of about 1,000 feet. The thickness of the ore has ranged from about 3 feet
to 8 feet. Approximately 25 to 30 percent of the developed area has
contained ore whose thickness and grade have been great enough to permit
commercial exploitation.

The tabular bodies of manganese that have been mined from the Silver
Hill formation, chiefly by the West Algonquin and Bernard mines, have been
persistent for as much as 50 to 250 feet along the strike; their dip
length has not yet been determined definitely. Their thickness ranges up
to about 50 feet, but usually is about 15 to 30 feet.

3881 -8-


Hole 10-S (Cont'd.)

H ; Distance | Core ; Core il Petrographic description
Footage | Core} drilled, jobtained, | recovery, Footage i
From-_\___To- i size| feet | tect a percent, From~ To- t
8h | 88 | Ex i 4 ' la" | kT. 84 88 | Medium to coarse-grained light-
| | : : | | gray limestme.
nn) i" 17 | 2t3” j 32.2 88 | 89! -‘Buff limestone - fractures 45
i t ' : | i | egress to core.
95 1 100 a) | 3°3" H 65.0 |i 89 i 99 Buff limestone - medium-grained.
wo | 15 | TM 1 5 1 an | 38.3. || 99 10h | Mn0p and quartz.
| i ; \ ; 104 105 =: MnO, stained limestone - fractures
: ! ! i. i 45 degrees to core.
105 ; lio fom os i otg* | 15.0 ‘|| 105 120 Coarse-grained buff limestone.
110 » 115 a a) 2to" | 40.0 jj :
15 120 a 2to" i o.o i :

3881 -5T- Interior - Bureau of Nines, Pittsburgh, Pa.


Hole 3-8 (Cont'd.)

‘Distance ij Core j Core Petrographic description
Footage Core | drilled, jobtained, | recovery, Footage
From- To- size feet | feet i_percent || From | To-
511 516 Ex | 5 _ kee 91.6 | 522 1 525 Light-gray, fine-grained marble
36 i ba ny 5 | 3h0" | 16.7 | with irregular darker bands and
5 | | 283 56.2 | mottlings.
525 530 “5 | 16" | 30c0 | 505 | sto | ray, Pinecgrained martle with
530 535 "i 5 1 16" ' 30.0 darker bands at right angle to
535 5h a) | stot | 100.0 i : core. Locally peppered with
: i ! i i dark spots.
Hole 4-S
Co-ordinates: 11,073N, 11,105 Depth: 495 feet
Elevation at collar: 5,764 feet Bearing: Due West
Dip: 60 degrees
° 9 Ax | 9 ao) i (o) i} 0 33 No core up to 9 feet Topsoil.
9 uw " 5 1 2toTM hoot } Remainder light-gray, coarse-
Wy 18 " 4 : B20" i 50.0 |! | grained marble. Jefferson -
18 23 nn) 393" | é5.0 || 1 H shows light stain of Fe oxide.
23 28 " 5 3'o" '  €Q.0 H | 31 to 33 feet, several frac-
28 33 " 5 3%0" ' 60.0 | tures at 30 degrees to core -
i i thinly coated with Mn0o.
33 38 "15 yer | 90.0 |} 33 43 Coarse-grained Jefferson. Some
i i i of it broken and friable and
| H Hl | lightly dusted with brow Mn05
i | (wad). Last 5 feet partly
| t brecciated and filled in places
| | with wad and Fe oxides,
43 48 " 5 o'5" | 8.3 | 43 | 48 Last 6 inches gray, coarse-grained
| | Jefferson. Remainder is
{ { missing.
4g hg " 1 ofu" | 91.6 48 8B Light-gray Jefferson. A few seams
hg 53 oy 4 310" | 95.8 of Fe oxides right angle to
53 58 "45 312" 1 63.3 core. At about 61 or 62 feet,
58 6 "1 5 36" + 70.0 : | 1/¥-inch seam of Mn03. Broken
: i : i and gougy just about 63 feet.
3881 - ho -




Hole 1A-U (Cont'd.)

' ;Distance ; Core |! Core : Petrographic description
Footage Core :drilled, | obtained, | recovery |: Footage

From- To- size feet | _ feet | percent |! From- To-
293-1/2 | 299 AX 5-1/2 438 1 77.3 | 296 309 White Hasmark marble.
299 30h " 5 3h" i 80.0
304 309 " 5 7 4t5" 88.3
309 314 " 5 i; 26" | 50.0 309 314 | Ne@ium-grained, gray, Hasmark

i i | : marble.
314 319 " 5 (212% 43.3 ; 31k 341 White Hasmark, locally fractured.
319 32h " 5 ! 218" 1 53.3
32h 329 ” 5 , 2am | hae
329 334 " 5 | 2'10" | 56.6
334 339 " 5 1 3taF | 6343 | .
339 3h ” 5 | 296" | 50.0 | 342 34118" |Vein about 80 degrees to core,
3hh 349 ” 5 arn" | 41.6 quartz-filled breccia.
3h9 354 " 5 {gt fF 93.3 3418" 379 White Hasmark marble locally
354 359 " 5 i Bf" | 98.3 ( fractured
359 364 " 5 4B", 93.3 i
30h 369 o 1 5 troy | 9626
369 374 " 5 13" | 25.0
374 379 " 5 | ktg# 95.0
379 33h ” 5 1 45" | 88.3 379 4206" |White Hasmark-local small
364 389 ” 5 wg" | 90.0 cavities.
389 39h ” 5 378" | 73.3
39h 399 " 5 2'11" | 58.3
399 Lok " 5 216" | 50.0
Lok hog " 5 Arye 91.6 i
409 Wah " 5 316" 70.0
any 419 " 5 yrge 85.0
49 heh " 5 41g" 93 3 hoot6" 499 Yellowish Hasmark, medium fine-
koh hog " 5 hte" 83 3 grained. Fractured in places.
4e9 43h ud 5 wr" 98.3 | At 448" 8", 1 inch of
43h 439 ” 5 yrsn 88. | silicified. breccia with
439 Add " 5 kro" 95.0 disseminated pyrite.
Abi 4g " 5 eT" | 9166 :

! oT Ake - 4ho'6" |Gray, fine-grained Hasmark.

| Dark-gray streaks. Scattered

fine pyrite, some cavities.
3881 -B-


Hole 5-S (Cont'd.)

Distance Core
tee Core | drilled, ‘obtained,
= } size feet i feet
276 et Ex 5 | arg"
281 286 " 5 | eto”
286 291 " 5 111"
291 296 " 5 otg"
296 301 " 5 16"
301 302 " 1 of10"
302 306 ” 4 oto"
306 311 ; * 5 o'8"
311 315 i” 4 aq"
315 317 8 2 1t1"
317 320 | ” 3 2137
320 325 ce 5 , ite"
325 331 78 6 | Qtgt
331 336 6) M5 19"
336 | 3ho pm ty | 113"
3h0 | 3h2 ae’ ' yto"
341 | 343 ; m5 2 1'3"
343 348 ane) on"
348 353 | " 5 ; tq
353 358 a) 38"
358 | 363 ae) 31"
368 | 368M 5 ; pro"
368 373 "15 ; Ae

3881

| Core Petrographic description
| recovery, | Footage
percent (| From To- t
45.0 276 281 | Fine-grained siliceous limestone.
, { Fractures coated with chlorite.
4o.o || 282 286 | Like above » core much broken.
38.3 || 286. 291 | Same as last, some fragments con-
| tain pink MnC03 and a little aS.
| 286-288 feet heavy zinc. (Tren-
i | gove) {assay Zn Ag Mn).
15.0 1 292 296 Small amount of core recovered in
i ! small fragments consisting of
! | quarts with some 2nS (assay Zn
' Ag)e
30.0 ! 296 301 | Fine, dark-gray quartz with a
: | little disseminated fine sul-
! | fides and some MnC03 (assay Zn,
i i Ag, Mn).
83.3 | 301 311 | Like above except less sulfides
20.8 | | and MnCO3 (assay Zn, Ag, Mn).
B.3 | i
39.6 || 311 317 :
5.8 |
75.0 ' 317 353 | Gray, fine-grained limestme with
23.3! | thin. cross laminae of darker
37-5 | gray. A few fractures 30 de-~
35.0 H | grees to core. In places,
{ 47 i dark-brownish siliceous bands,
; 100.0 } : and near the lower end some
| 63.2 areas peppered with dark specks.
18.3 ||
31.6 | .
73.30 i 353 | 388 Typical Maywood with local frac-
61.7 | turing.
100.0 | i
81.7: 1 \
~ 4g.


Hole 5-S (Cont'da.)

Footage

Distant

Core

Core

Pet:

Core | drilled, | obtained, | recovery, | Footage

phic description

From- | To- size feet | _ feet ‘percent f From- To- H .
an vr
Wh | Wg} Be} 500} aa") 58.3 fy | | 2 inches gougy mterial.
i ! | i47k | 479 | 2 feet of core ~-fine-grained,
| | i 8 | | xeddish-brown shale or shaley
i | { | i | -limestone ~ may contain some
H H : ! ; garnet.
479.0 | Gh " 5 | 3the 66.7 i 48h Same - contains a few thin seams
| ! { i ! i of thulite and disseminated
i : | i | A i pyrite in places.
WBho | WBS i oto" fo | 485 | No core - hole cut into Headlight
| \ H i : i | winze. Went through mck pile
! i : i and into footwall of Headlight
| ; \ bed.
4g5 | eT 2 ; oom" | 38.5 1485 | 87 | Only 3 inches of core - porous,
! i | i i ' | siliceous, black manganese ore.
i ! ' ' ! : | | Soft pyrolusite mixed with
- ! : | i i i quartz.
M87 | hon ; otto" = 20.8 ;; 487 ' 496 White to. gray, medium-grained
hop 96 OS ; 188" | 33.3 ! marble with chlorite seams at
' i | | i : | 80 degrees. First two inches
: i ' i : yellow and friable.
Hole 6-8
Co-ordinates: 12,044N., 11,160E. Depth: 160 feet
Elevation at collar: 5, 848 feet Bearing: S. 60° We
Dip: 41 degrees, 30 minutes :
T 7 T
oO | 37 4 Ax i 37 i i 0 ! 37; Decomposed granite.
37 | 39 «| Ex! 2 | ite" 83.3 ft 37 | 39 | Dark-gray Limestone with Mn0p and
i io ‘am.
39 uo | 1 | ou | 8.3 «|| 39 i 51 | Mn0o.
io | ou | 4 otto" i 20.8 | \ |
ee ee | 3 | om” ; 305 | | !
wf wg fy 2 , 08" + 33.3 kt 1 |
4g Sh "|e 03" | B56 ft | !
3881 - 51 -


Hole 6-8 (Cont'd.)

i : Distance Core Core i 4
_____ Footage | Core! drilled, i obtained, | recovery, fT Footage Fetrographic description
From- To- size feet | feet | percent i From | To-
sl Ex | 3 ian | 36a | sn | |
24 | 29 E: 3 | oege | as i} | 39 | MnOg and quartz.
59 | a ” 5 os" | 83! i |
tho! qj ; * 6 | 6" | 25.0 i a 0 | Seo
To | 6 | *® 5 | ora; 330° TO | 8 mao, ang arte
BH 1.8 ; " 5 | ° | poo?
Be ae aon |e
! "1 20 oume 0.7 3°83 ' 103 |
103 109 . | 6 | O81" o.1 | 103 i 109 | moe Gnd quartz.
rif i hig i . ' 2 : oa" \ 16 “7 i! 109 i ab | MnOo and 2 inches limestone.
| : 3 63 : 14 119 ;  Mn0g with scattering pyrite
"of t Fait ! HT i crystals.
ug ue | : 3 ore" \ 5.6 * 119 : 122 , Mn0p and quartz.
me fer 1 3, oem | ae ear |e arn Gare
ne | 6 03, te 1 27 | 160 | Typical buff Jefferson limestone.
138 (jw | * | 3 : 7 a i !
U1 Pouye bg 1 oth j ’ |
i : 1! | ! 6.7 : !
146 ; DL | : 1/5 a ae 25.0 } i :
D1 , 156 ers > 210" 56.7 | i :
156 160 ik if" 26.7
Co-ordinates: 11,643N., 12,203E. Hole Te
Elevation at collar: 5,810 feet Depth: 360 feet
Dirt lo degrees Bearing: N. 60° W.
0 1 Bk 1/7 * 84 i ° ‘8h
8h H to " i i Granite.
oe i id : Ex l pat M91 : 8h. | 89 ; MnOg, quartz and limestone.
50 2, Poa: 10", 7500 j 89 | 90 | Buff Jefferson limestone.
a a Do 1¥10 45.8 | 90 i 94 ; Granite and limestone.
7 i 93 org’ 25.0 | : 97 | Buff limestone.

1/ Core size:

3881

0 to 57 feet, Ax; 57 to 84 feet, Ex.

-52-




INTRODUCTION AND SUMMARY

Introduction

Shortly after the Strategic Minerals Act of 1939 was passed by Congress,
the Bureau of Mines was authorized to begin a program of investigation of
domestic sources of strategic minerals, Since World War I, the Philipsburg
district had been virtually the only one in the United States that was
producing manganese on a commercial scale, Consequently, the district was
among the first to be investigated, During the summer of 1939, the Geologi-
cal Survey mapped the geology and ore deposits of the district, In late
July 1939 the writer examined the district for the Bureau of Mines. On the
basis of this examination and of the work performed by the Geological Survey,
the Bureau of Mines diamond-drilled at several properties in the district
during the summer of 1940, This report reviews the mining history and
geology of the district, and presents the factual data obtained by diamond
drilling,

Summa ry

The Philipsburg district is about 45 miles, air-line, northwest of
Butte, and about the same distance southeast of Missoula. Nearly all the
manganese mines are within an area of about 1 square mile whose center is
about 1 mile due east from Philipsburg. Some silver mines, however, are a
mile or more east, southeast, or north, of the manganese-producing area.

The Philipsburg district produced at least $35,000,000, chiefly in silver ore,
before 1900. Since 1900 it has produced 539,000 tons of plus 35 percent man-
ganese ore, 24,700 tons of zinc, 8,111 tons of lead, 80,000 ounces of gold,
and 20,840,000 ounces of silver. Virtually all of the manganese ore has been
produced since the beginning of World War I. Except during World Wer I,
nearly all of the manganese production has been concentrated to a grade of
about 70 percent Mn0p and sold for use in the manufacture of dry batteries.

The manganese deposits in the Philipsburg district are in sedimentary
rocks of Paleozoic age. These rocks have been folded into a symmetrical
angicline whose axis strikes north-south, and which plunges north at about
25°. The: east flank and the south end of the anticline terminate against
egranodiorite of the Philipsburg batholith. Numerous east-west tension
fractures are in the sedimentary rocks and in the granodiorite throughout an
area several thousand feet wide on each side of the sedimentary-granodiorite
contact and about 8,000 feet long on the strike of the contact. The fractures
contain numerous shoots of zinc-silver-lead ore in a gangue of quartz and
rhodochrosite. Limestone members of the sedimentary formations adjacent to
the fractures contain numerous irregular replacement-type ore bodies of
manganese oxides and a few vein-type deposits. These deposits presumably

3881 -1-




The Ore

Sulfide ores occur almost exclusively in vein deposits. Although
the amounts and proportions of. the various sulfides differ from place to
place, the composition of nearly all veins, whether they are in granodiorite
or in the sedimentary rocks, is similar. Most veins contain sphalerite,
galena, and tennantite with some pyrite, chalcopyrite, polybasite,
pyrargyrite, and proustite. Quartz is the most abundant gangue mineral, but
rhodochrosite generally is present. In some veins, or parts of veins,
rhodochrosite is notably abundant. Ankerite, calcite, and barite usually
are present in small amounts. Oxidation of the sulfide ores is strong in
the upper parts of the veins. The depth of oxidation differs markedly from
Place to place; nevertheless clean sulfides seldom can be mined from depths
of less than 500 feet, The Granite-Bimetallic vein was impoverished by
leaching to depths of 50 feet to over 300 feet; below the leached zone it
was enriched by secondary silver minerals to depths of 400 to 1,000 feet.

Production records indicate that the average recoverable metal content
of the ores mined from the veins in sedimentary rocks was about 5 percent
zinc, 1 percent lead, and 13 ounces silver per ton. Most of these ores
were wholly or partly oxidized; consequently, very few attempts were made to
concentrate them. The average silver content of the ores from the Granite-
Bimetallic vein is estimated to have been about 150 ounces per ton; the
primary ores in the lower levels average about 12 to 16 ounces silver per
ton.

It is the opinion of most geologists who have studied the district that
rhodochrosite is the primary manganese ore of the district. Also, it is
conceded generally that the rhodochrosite was deposited later than most of
the sulfide minerals. Rhodochrosite not only occurs as vein fillings but
as fine-grained replacements of limestone. Probably the replacement type
ore bodies of manganese oxides were derived from replacement deposits of
rhodochrosite, Although no large high-grade replacement deposits of
rhodochrosite have been found, Pardee. Gf has estimated that the porosity of
the manganese oxide bodies is approximately equal to the theoretical
porosity that would result from the oxidation of rhodochrosite. The failure
to find high-grade replacement deposits of rhodochrosite may be explained
by the theory that they have been oxidized to the greatest depths mined,
whereas smaller or lower-grade deposits have been less permeable.

The manganese oxide ores of the district are composed chiefly of
pyrolusite. Nevertheless, considerable psilomelane and some braunite,
manganite, and wad are present. Most of the manganese oxide ore mined from
the Hasmark formation has contained between 30 and 40 percent manganese, 20
to 25 percent silica, 2.5 to 3.5 percent iron, and less than 1 percent lead.
Most of this ore has been raised to battery grade by magnetic concentration.
The concentrates contain about 47 percent menganese (70 percent Mn0o), 10
to 15 percent silica, 1.5 to 2.0 percent iron, and 0,15 to 0.2 percent lead.

67 See footnote 4.

3681 -9-


RSW Riaw Ris Ri2w RuW RoW
YD
JENS TION
=
~
F f Ny
AK {/
| os zr wy TON
DUNKLEBERS
= I © pd
a) ewoensow” y) 2)
HENC
9 x z
AXVILLE
SS &
x le
COMBINATION TeN
&
( ; i, | weer &
ly
7. -
w {Philipsburg batholith &
« {| wirgclep g
> FEASTS TM
AA a4
x PHILIPSBUR' EWS rae en rN
Q o 24. io SonAnITETM bimerauite loa ly
q Sf CASS
Area of fy, Fars ORS VY |g .
I figure 2 &} ie” Ke = DANIELSYLLE sen Umm sd
9 & ao U0 . T6N
ov N
es Reawre
oe Nv &
Wo
& \
T
. TSN
— Dw

T T =—
5 ° 5 [TS

ANACONDA

SCALE IN MILES

Figure |. - Location of Philipsburg mining district,
Granite County, Mont.


3.600"

SAMPLES
Tengih Percent
feet [Mn | Fe_| insol_[ Zn
5 [41 [104] 1684 |— 5500
s [6 [ete] iia} —
3_|-49 Tose [2424] —
30.08 fa. — {sa
5s | — |—}—Tee
a oe EY
ee
sf — == Tis
a
Creore Sesludge

400"

300

SECTION

ALONG 0.0. HOLE No. 2-U.

gv Fissure veins
(ehietty zine, 10, silver)

Manganese ore
in limestone beds

Granodiorite

LeveL,

00-Fo
Scale in feet.

Figure 5. - Plan and vertical section through drill hole 2U, showing 300 and 500 levels, Scratch Awl mine.


Bureau of Mines
Report of Investigations 4723

INVESTIGATION OF MANGANESE DEPOSITS
IN THE PHILIPSBURG MINING DISTRICT
GRANITE COUNTY, MONT.

By S. H. LORAIN

United States Department of the Interior — October 1950

metadc38548



Hole 1-S (Cont'd.)

Distance! Core Core je Petrographic description
Footage Core | drilled, obtained, “recovery, ‘ — j
Fron- To- size feet feet i percent || From- i
! i
317 322 Ex 5 3°6" 70.0 i 33 : see Sandy limestone - Maywood. At
HI i 316'2" of brecciated, cemented
i] \ by calcite.
322 327 " 5 17" 31.7 |, 32376" | 339 Medium-grained marble with black
327 332 " 5 33 loo. jj H bands (biotite) .
332 337 ud 5 aie 46.6 jj i
337 339 ° 2 on" 138 | . .
339 343, " 4 ane. 58.3 || 339 ; 535 | Typical Maywood, fine-grained,
343 346 " 3 113" WT | study limestone. Locally
346 351 " 5 argv 55.0 | ; steaked with biotite and
351 356 " 5 Ste 100.0 | | ocassional layers of marble at
356 361 " 5 5'0" 100.0 || H 429 feet.
361 365 ” 4 312” 19.2 |
365 370 " 5 3hn 66.6 i
370 375 " 5 513” 100.0 !
375 380 " 5 5! 00:0 | \
360 385 " 5 5 100.0 j
385 390 " 5 5! 100.0 |!
390 395 " 5 3'7" eT |
395 400 ” 5 213 45.0 |
400 405 " 5 2'10" 56.7 i !
4o5 410 * 5 to” 80.0 || |
410 ki5-1/2 | 5 3°38" 73.3 | i
415 hig-1fe | y-afe | ite" 33.3
419-1/2 | heh-1fe |" 5 Arh | 86.6 |
yak-ife | he6-1/2e | TM 2 at + 100.0! |
426-1/2 | a9 "  ) eae | ae leg
429 434 " 5 yr5e |; 88.30 | :
ugh 139 “15 aren 50.0 |
W390 | » 13 ' 10010 |
ehh Akg " 5 R10" 96.6 | i
Mg 45) " 15 at 40.0 | i
45h 458 "15 ate 33.3 i

3881

~ 28 -


copper have been associated with the silver and manganese ores. During the
period of high silver production, the zinc, lead, and copper-bearing
minerals were wasted. Since World War I, however, considerable quantities
of zine and lead have been rdcoveréd} some mines were operated chiefly for
their zinc-silver-lead ores. :

The officially recorded production records of the Philipsburg district,
as compiled by Needham,2/ are tabulated in table 1.

PHYSICAL. FEATURES AND CLIMATE

Philipsburg is on the eastern edge of Flint Creek Valley, 5,200 feet
above sea level. Flint Creek originates about 10 miles south of Philipsburg
and' flows almost due north 35 miles to join the'Clark Fork'Rivér at Drummond;
its valley, in the vicinity of Philipsburg, is about 3 milés wide and is
nearly flat. Cattle raising is the chief industry.

The Flint ‘Creek Range rises abruptly from the edge of Flint Creek Valley
a few thousand feet east of Philipsburg. Within about 1 mile, ‘the ridges
attain an altitude of about 6,000 feet. About 8 miles east of Philipsburg
the highest ridges of the range are nearly 9,000 feet above sea level. Most
of the mountain slopes are covered with dense stands of lotigerole pine; some
larger timber is in the more sheltered valley. The Flint Creek Range is
within the Missoula National Forest.

Annual precipitation at Philipsburg is between 15 and 20 inches. About
a third of this falls during May and June; the remainder is distributed
fairly evenly throughout the year. Extremes of temperature range from 20°
to 30° below zero to about 90° above zero. Below freezing temperatures
may be expected at any time between late September and late May. Usually,
the snowfall is not heavy; snow depths at Philipsburg or at the nearby mines
seldom exceed 1 or 2 feet. Road maintenance because of snow is not difficult
except at the highest and most distant operations.

DESCRIPTION OF DEPOSITS

General Geology

The regional geology has been described in considerable detail by Emmons
and Calkins 3/ The geology of the manganese deposits was described briefly
by Pardee/in 1921 and was described in considerable detail by Goddard2/ in
1940. The following description of the general geology is based on these reports.
2/7 Needham, C. E., supervising engineer, Metal Economics Division, Federal
Bureau of Mines, Salt Lake City, Utah.
3/ Emmons, William Harvey, and Calkins, Frank Cathcart, Geology and Ore Deposits
Soa Philipsburg Quadrangle, Mont.: U. S. Geol. Survey Prof. Paper 78,
913.
4/ Pardee, J. T., Deposits of Manganese in Montana, Utah, Oregon, and Washing-
ton. U.S. Geol. Surv. Bull. 725, 1921, pp. 146-17h,
5/ Goddard, E. N., Manganese Deposits at Philipsburg, Granite County, Mont.:
U. S. Geol. Surv. Bull. 922-G, 1940, pp. 157-204.

3881 -he


PROPERTY AND OWNERSHIP

Subsequent to examination of the district's mown manganese-producing
properties, the Bureau of Mines further investigated the following
patented lode claims by diamond drilling:

Claim Present ownership

BOWLE sessecececececece Earl Bellm, Philipsburg, Mont.
Chicago e+e. vee .
Little Dandy e.essce Do.

Casey seceveccsevccosereces Contact Mines Corp., Philipsburg, Mont.

Cliff No. 2 .
Seal Rock .. Do.
Horseshoe «ssesesece C. Hickey, J. A. Harrah, and T. Hickey
Estate, Philipsburg, Mont.
Do.
Do.
Do.
Do.
Scratch AW] sececeseceesees Owned in April 1940 by the Phillipsbugh

Mining Co.
HISTORY AND PRODUCTION

The town of Philipsburg was founded in 1867, 3 years after a prospector
named Horton discovered the Hope silver mine. Philipsburg was named in
honor of Philip Diedesheimer, who came from the Comstock lode in Nevada to
erect the Hope mill at the time the town was founded. The Trout, Algonquin,
Poorman's Joy, and other mines were opened in quick succession. For many
years thereafter the district was noted chiefly for its production of rich
silver ores. The period of greatest prosperity was from 1881 to 1893, when
the Granite and Bimetallic mines, about 3 miles southeast of Philipsburg,
were at the peak of their production. Production records for the early
years are not complete; nevertheless it may be estimated, conservatively,
that the district produced at least $35,000,000 before 1900.

The first recorded production of manganese was made in 1900 from the
Coyle mine. Very little manganese was produced, however, until about 1916,
when the demand for it in the steel industry was stimulated by World War I.
Manganese production then increased rapidly until 1918, when over 127,000
tons of manganese ore was produced. After the war the district was unable
to compete with foreign sources of metallurgical manganese, but it was
learned that the ore,.after concentrating, was well suited for use in dry
batteries. Since then a small.but fairly consistent production of battery-
grade manganese has been maintained. During World War II a considerable

tonnage of ore, which consisted partly of pyrolusite and partly of rhodo-
chrosite, was purchased by the Government and stock-piled.

Although past interest has centered first on silver production and then
on manganese production, considerable amounts of zinc and lead and some

3681 -3-


“Hole 3-S (Cont'd.)
S

| Distance Core Core Petrographic description
Footage Core | drilled, | obtained, | recovery, Footage
Fran-__ To- size feet feet percent Fran- To-
353 | 358 Ex 5 510" 10030 35016" | 388 Gray, fine, limey hornstone.
358 , 363 ” 5 510" 100.0 | Local fractures with golige end
363 | 368 " 5 Aro 80.0 chlorite. Irregular spots of
368 | 373 a | 5 em" 58.3 | white carbonate here and there.
313 | 378 "7 5 argu 55.0 i
378 | 385 " 5 ron 80.0 H
38 | 588 | 5 433 8.0 |
388 | 393 " 5 4g" 98.3 388 483  '!Dark-gray, fine, limey hornstone
393 398 " 5 i aren 5303 \ | | bended at right angles tocore.
398 403 " } 5 1 3t5it | 68.3 =! i ' Local bands of black hornstone.
hoz 408 ® | 5 5108 | 100.0 { | Core borken and gougy in places.
408 | 40 " 1 2 17 79.1 : ;
wo | 4a5 " 5 i eae | gry! | ‘
45 | eo nn) + 311" i @.7 | |
4e0 | 45 a) | Brom 100.0 | { !
he5 1 430 " 5 t keto# 96.7 | { |
130 | 455 " 5 yazo" | 96.7 I : i
455 | 4ho ” 5 Arlo" 96.7 jf : i
Aho Abd " 5 1110" 36.7 | i !
4Y5 | 4S " a ne 83.3 | | l
Wag) 45k " 5 ere" 1 33 i i
Ag | bg " 5 ai" | 38.5 |
459 | hob n 5 | 319" 75.0 | i
46h | 469 " 5 ; 318" i 1363 ' i
Ne | 4re a ee
hye} dry ® 5} kee 1 gsts | |
477, 480 " 3 { 016" 22.2 | : :
480; hes ” 3 e110" ghd : .
483 | 486 " 3 ero : 66.7 4.83 5ll | Light-gray, fine, silicious, cal-
486 | 4o2 " 5 a5 { 48.3 | | careous hornstone; scattered
hor | 496 . 5 ; 4s" : 98.3 : | specks of pyrite. At 506!-511',
496; 501 id 5 ai" : 2167 H ; much brown garnet.
50L ! 506 ” 5 4r20" ! 96.7 | :
“506°: ” 5 + atom, | 40.0 ot
388. : 1 ans as



Hole 2-U (Cont'd.)

\Distance | Core { Core Petrographic description
Footage | Core !drilled, |obtained,| recovery,!, Footage 1
Fronm- | To- size | feet feet percent | From- H To-
200 | 20k Ex 1 4 1tot | 25.0 || 200 | 220 | Marble cut by numerous fractures.
204 208 " 4 2atgn 6.8 || | H Mostly 45 degrees to core and
208 213 " | 5 ame 46.7 | coated with brown films of Fe
213 218 " 5 2g” 55.0 and Mn oxides. Core is mostly
218 223 " 5 3h | 66.7 | broken to pieces 2 inches or
| less.
223 228 " 5 ane 26.7 220 243 «| Light-gray fine-grained Hasmark.
228 233 " 5 yto® 80.0 Occasional fractures with Mn0o
233 238 * 5 010" 16.7 | films. Locally, rock shows a
238 2h3 " 5 2'6" | 50.0 \ greenish cast (chlorite?).
i |
2h3 2h8 * 5 1'8” 33.3 |) 2h3 ;  2he Marble. Brownish with dust of
| MnOp (wad). Some fractures
| with Mn0p films.
28 253 " 5 115" 28.3 || 2h8 253 Mostly quartz with some fine-
i grained sulfides. Core broken
! | to small fragments (assay for
| Zn, Ag).
253 258 nol s 113" 25.0 253 258 Small amount’ of core - recovered.
| H i Consists of fragments brown
| with MnO dust.
258 262 " us 1'o" 25.0 258 262 | Small part of core recovered.
| Consists of fragments of gray
i marble cut by fractures with
; Mn0z filns.
262 263 " 1 org” 75.0 26 263 Fine-grained quartz with dissen-
| ! | | i gnats fine sulfides (assay Zn,
H : i i! | i Ag).
263 | 268 " 5. ; oMlo" | 16.7 263 268 Small amount of core recovered,
. : | i consists of quartz fragments
{ Hy containing fine disseminated
H i
i | 1 | sulfides (assay Zn, Ag).
3881 - 2h -


Hole 1A-U (Cont'd.)

Distance Core | Core Petrographic description
Footage Core |drilled, jobtained, | recovery Footage
To- size feet feet percent. From To-
yk AX 5 Ares 90.0 Medium-grained white Hasmark
149 ” 5 4g" 3 3 H marble. In places small
154 ” 5 ign B 3 | cavities with limmite
159 " 5 3f11" 78.3 Medium White Hasmark. Few small
164 " 5 25" 48.3 153 229'6" cavities. Locally fractured.
169 " 5 hie” 93.3 Scattered specks of pyrite.
174 " 5 4rg” 93 3
179 ° 5 318" 3.3 Il
184 " 5 319" HO |i
189 ” 5 310" 60.0 |
19h ” 5 irge 95.0 |
199 " 5 ise 88.3
204 " 5 319” 75.0
209 " 5 kre 91.6 Il
a4 " 5 318" B33 |i
219 " 5 3°86" B23
22h " 5 krgn 93.3
229 ” 5 Ato" 96.6
232 i " 3 at" 63.9 | 22916" 296" White Hasmark marble with few
237 " 5 Arg" 85.0 i cavities and fractures. At
ake " 5 3°7" 71.7 252! 2" a h-inch streak
eke " 5 yarn 91.6 stained brown.
252 ” D 313" 65.0
257 " 5 eye 91.6
262 to 5 kro" | 95.0
267 " 5 ktof 95.00
aje-1f2) " 5-1/2 yoy 83.3}
278 ” 5-1/2 yee 81.8 |
283 i * 5 yige 85.0 1
268 020%=~C=«‘P 5 3tov | 9343
2g3-1/e; * 5-ife | ki" | 87.9 |

-p-


Hole 1-S (Cont'd.)

| {Distance | Core | Core Petrographic description
Footage Core jdrilled, jobtained, j| recovery, Footage ;
From=_' To- size feet feet percent || From- i To- u
458 463 EX 5 218" | 53.3 | | Typical Maywood, fine-grained
463 465 " 2 17" 31.7 study limestone. Locally
465 470 : 5 ath 5505 | steaked with biotite and
we rhe cn 4 i io 31.2 | ocassional layers of marble at
ure | 79 » 13 gt oo | "29 feet.
479 4gh eof Ss kre 5.0 |
4h. 489 " 5 213" 45.0
489 Loh " 5 ren 90.0
koh | 499 " 5 17" 31.7 |
499 50h, " 5 ANo" 96.7 |] |
" " 93.7
513 518 " 5 ate" | 50.0
518 5e2 " i 4 15" 35.4
522 527 " 5 aye 26.7
527 530 " 3 i 1tio" 61.1
530 535 " 5 | St 100.0
535 | 5ho " 5 Ato" 96.7 535 540 Dense greenish rock with some
i thin bands of garnet.
5ho Sh5 " 5 5! 100.0 540 543'6" | Chiefly gouge with fragments of
marble and garnet rock. This
| may represent the Headlight
bed veins. The position is
i evidently below the oxidized
zone, and therefore no black
i | stain (Mn0j) would be formed.
| i No pink (MnC03) was seen, but
H | it might be present and con-
\ ! cealed by the gouge or too
| Pale in color to be recognized.
3881 “= 29 -


DESCRIPTIVE LOG

Hole 1A-U
Co-ordinates: 8972N, 9835E Depth: 1,250 feet
Elevation at collar: 5,560 feet Bearing: N. 10° W.
Foota core i pistance bt Core f = Petrographic description
Le j obtaine recovery } footage i
From-_/ To- size feet , feet , percent 4 From=_ To-
0 5 Ax 5 a a) No core. Casing.
5 2 , 4 310 1 95.8 5 25'6" !white Hasmark marble. Many iron-
a 18-1 : ; Lp pee i a7 ! stained fractures.
w-iy| sapl " 5 318" | 73.3
23-1/2 28-1/2 " 5 oflo* ; 16.7 i 25.6" 28'6" | Fine-grained quartz with limonite
ij i and manganese oxide strains in
i i veins.
28-1/2 34 . 5-1/2 o'lu” | | 16.7 | 2816" | ok White to yellowish Hasmark marble
34 3 ° 3 U9" 35.0 with yellow-stained fractures.
i" 21.7 |
ii 49 " 5 rie b> 26r7 | |
hg 5h ” 5 ato” |° hoo |
oh 59 . 5 3°11" 78.3 5h 70'7" |White Hasmark with few fractures.
2 6h . 5 316" 70.0 Between 48 and 69 feet two
69 5 4g B 3 fairly prominent sets of frac-
a tures intersecting at 60 degrees.
69 TH , 5 —4g9 93 3 Medium-grained white Hasmark
7 19 : 5 468 90 .0 70'7" 153 marble. In places smlall
R a 5 ea 95.0 cavities with limonite.
f " 5 it 1.
89 oh " 5 sr a6
ony 99 ” 5 No" 96.6
99 104 " 5 2tg" 55.0
104 109 ” 5 ; 33" 65.0
109 14 " 5 j 26" 50.0
114 119 " 5 3to" 65.0
ng 12h " 5 Aton 95.0 ft
Jah 129 " 5 AtI0" 96.0 ft
129 2B " 5 kro" 80.0
134 139 ” 5 a aad 91.6
3881 -u-


Hole 5-S (Cont'd.)

: | Distance : Core - Core Petrographic description
Footage ; Core; drilled, ‘obtained, | recovery, Footege j
From-_| _To-__: size’ feet; feet | percent || From- | To- |
156 wi} oak | 5 ' BG" =} g0.0 i 156 | 169 | Pale buff, fine-grained limestone.
161 166 H . i 2 | Hee {80.0 |! ' In places core mich broken.
i 93.3 i '
171 176 | oo» 5 ; 5to" | 100.0 |) 169 ' 181 Gray, medium-grained limestone.
176 181 | " 5 i AMlo" |. 96.7 i | Many indistinct cross laminae
i ! L ij i | of darker gray.
181 186 i; oo" 5 i 5to" i 100.0 i 181 : 220 Mostly pale~yellow, medium-
186 | yo 0OU«d|lCl" i / lot 5 25.0 |! ; grained limestone. In places
190 195 | " 5 i 5to" 1 100.0 i| | | rock is friable and broken;
195 Bo . 5 | en i 90.0 | | some gouge at 215 feet.
0! ; : .
205 210 | +" 5 1 3t5" | B35 il | i
210 a5 | 8 5 / eflo" | 56.7 |! | '
215 220 «| SO 5 4 our | 38.30 : i
220 225 ; 5 1 kta | 98.3 11 220 | 2ho | Medium- to fine-grained gray
225 230 { " 5 36" | 70.0 i | limestone with darker laminae
230 235 i % 5 ts 28.3 |; i right angle to core. Locally
235 2ho , * 5 a 46.7 |! | : much fractured and shows a
H t | ( i fcnloritess inineral
: : li | chlorite).
2ho a5 | Bx | 5 7 2tgn | 55.0 i 2ho | 258 (Begin 7/8 inch core) Like above.
2h5 ahy oj 8 | 22" | 5B | Some gouge at end.
ohe an i " | | to" | 25.0 |
251 256 : " 5 am" | ky} | \
256 261 fo 7 5 ate" | 50.0 = |} 253 i 261 | Light-gray, medium-grained aplite
i i i ! i and granite: Dark minerals
| | i \ ! | relatively scarce.
261 266 | "1 5 1 2g" | 53.3 | 261 | 271 Gray to greenish-gray, fine-
266 271 ; | 5 ; 16" | 30.0 i | grained limestone. Some gouge
| : | i H at beginning. Core much
| { \\ | 1 broken.
271 276 ; " 1 5 16" : 30.0 i 271 i 276 | Fine-grained gray quartz, locally
i | if i : cavernous. Shows some fine
' i sulfides (assay Zn Ag).
2881 - 48 -


have been derived by oxidation of primary rhodochrosite ore bodies. Develop
ment at greater depth is expected to disclose bodies of rhodochrosite ore
whose size and manner of occurrence is similar to the manganese oxide ore
bodies that have been mined. A few small rhodochrosite deposits already
have been mined in the lower levels of some mines.

In an effort to stimJlate manganese production by indicating the position
of additional ore reserves in the Philipsburg district, the Bureau of Mines
completed 4,019 feet of diamond drilling from surface Stations and 1,528 feet
of diamond drilling from underground stations during the period June 1, 1940,
to December 6, 1940. The locations of the holes, description of the forma-
tions intersected, and analyses of the samples obtained by drilling are given
in this report.

ACKNOWLEDGMENTS

The writer wishes to acknowledge his indebtedness to Russell R. Trengove ,
project mining engineer of the Bureau, whose maps and records constitute the
basis for this report.

J.T. Pardee and E. N. Goddard, geologists of the U. S. Geological
Survey, provided assistance and advice that were of great value in the
conduct of the investigation. Mine operators and prospectors of the
district gave unlimited access to underground workings and mine records;
they also were most generous with their time and personal efforts.

All chemical analyses of samples were made under the direction of the
late E. S. Leaver, supervising engineer, Rare and Precious Metals Experiment
Station, Federal Bureau of Mines, Reno, Nev.

LOCATION AND TRANSPORTATION

The Philipsburg mining district (known also as the Flint Creek mining
district) is in Granite County, Mont., about 45 miles, air- line, northwest
of Butte and about the same distance southeast of Missoula (fig. 1). The
road distances to Butte and Missoula are 5h and 78 miles’ respectively. Both
routes are on paved highway U. S. 10.

The town of Philipsburg (pop. 1,200) is served by a branch line of the
Northern Pacific Railway. The branch joins the main line at Drummond, 25
miles north of Philipsburg. This road does not provide passenger service.

Nearly all of the manganese mines are within an area of about 1 square
mile, whose center is about 1 mile due east from Philipsburg. ‘Some silver
mines, however, are a mile or more southeast, east, or north of the manganese-
producing area. Access to the mines from Philipsburg is by winding mountain
roads which climb from an altitude of 5,200 feet at Philipsburg to about
6,000 feet at the mines.

3881 -2-




Co-ordinates: 11,012N, 11,2028 ° Depth: 540 feet
Elevation at collar: 5,70 feet Bearing: Due West
Dip: 60 degrees-0 :
| | Distance! Core Core jj Petrographic description
Footage ; Core} drilled, ; obtained, | recovery, |: Footage i
Erom= To- size feet | feet percent || From- To> t
ne Ze Ax lo | te) (0) 0 115 | No core. Decomposed granite.
| a 5 fe) : ; .
15 | 120 io" 25 tom 75.0 i 115 128 Mostly white, coarsely crystal-
120 | 12h " 4 2"10" 70.8 |i line marble (Jefferson). Fri-
- | able, porous, and slightly
| iron-stained in places,
leh ; 30 Ex 6 ytor 79.2 i 128 1230 Light-gray marble - a small
| | cluster of pyrite grains at
! | - about 128'8".-
130 135 Ax 5 216" 50.0 | 130 he Pale-gray to buff marble (Jeffer-
135 140 " 5 2a'6" 50.0 i son). Core mich broken at 130
140 U5 Ex 5 5t0” 100.0 j feet plus.
145, 150 " 5 l'o" 20.0 |, 1he 195 | Light-gray to buff, medium fine-
150 155 " 245 att 98.3 i i grained marble. Locally frac-
155 160 ” 5 218" 53.3 |! | tured, porous, and friable.
160 | 165 " 5 Atom 80.0 |i H : :
165 | 270 . 5 ary 51.6 |!
1700 | 195 " 5 atom. 55.0 || ;
175 180 7 | 5 12" 23.3 |
180 185 " 5 3139 65.0 |.
185 190 " 5 3h" 61.7 || |
190 195 " 5 yt" 98.3 H !
195 ; 200 | " 5 313" 65.0 | 195 au | Light-gray granite (intrusive).
200 i 205 i," 5 eaten 43.30 | oh 245 | Yellowish, fine-grained marble.
205 =| 210 ,* 5 yrge 95.0 i |
ap laf [3 | dae | Bed |
i 5 1°11 38.3}! |
220 225 i" 5 1'3" 25.0 | |
225 230 " 5 18" 33.3 || |
230 235 " 5 2tE" 53.3 |
ae af 5 | ane | |
i) i 5 + lo" 36.7 4 !
3881 - 39 -


Ho:
Hole 4-S (Cont'd.)

Footage
j 5
From- Toe + Core arilie a ; Core |
398 _ Sore) alice, |ovetnes,/ ezorery, |
ar iste) eecreny, ae
koh | 708 «| 2 | kre" reent |, From- ote Phic description
hog. We bom 5 i 5t0" 93.3 130 =| To- i
pans hig Pom ES Stor | 100.0 | i yo6 |
kig | hes Po" | 5 ign | 100.0 jj i , Gray, fine-grain
wos | not Age 90.0 | | ; Closely ed limesti
Ne 30 m6 ; spaced one «
30 | 435 ; 15 510" 93.3 i and brownish-; dark-greenis
435 | ho ine | 5 [kegs 83.3 || | | angle to ¢ gray laine ri
Wo sk m5 i wigt | She | koe ores ent
wks isa wl i 510" | 95.0 | | hye | Pine:
12 | 452 o | 5 Bato" 100.0 i : ‘ne-grained lime
2 | 457 "2 yrgt ae i | greenish- may. stone Mostly
i an ton . i H °
ies he a 3 ee 23h | | rown garnet. cal patches
et ie " 1 3 | &tjo" 2 TOE | ‘
fe} He 5 sor | aks
a oe oe ms) ||
ms i atow | 78.30 | |
| | | ie" | fo ae |
no} i | 233 | 7 } kB |
; 485 ! ! L:
| "i 3 | ight-buff medium:
i i ‘" i os grail
i | 0" | Gegnece toca m-greined }ne-
nes |B i | 485 | Smell soe fo core. Shove a”
7 ton Fp ; \ hi | | Small iron Stains a lit-
Hy i iH 1 H 0!
| 1 , gh if ! Consists core recove:
487 | /  @ i f dark- of small Ty
i ge low i i 5 M5 I ae vk grey Shi neoug ements of
‘ i ' 487 | ocally i: S rock
i ! 3 ern | k i | | Pale selon tather soe °
: t i 2
1 : i 1.7 | 487 | 4 grained Me ener Sort, fine-
3881 | 495 | Gray to ; ore mch
i | i greenish-,
' i i grained li gray, fine-
i | irregular mestone showing
- 46 - (darker ery. laminae of


Hole 1A-U (Cont'd.)

7 Distance ; Core Core { Petrographic description
Footage Core | drilled, jobtained, | recovery | Footage pote
From= | To-__| size feet __feet percent | From- | To-
920 | 985 Ex 5 ato" 4o.0 || 920 1030 | Tien buff, medium fine-grained
925 { 930 " 5 ‘ofl 18.3 | marble (Hasmark). Locally
930 3 " 5 arg" 33 cavernous. A little Mn stain
935 re) “ 5 2tor me) in places. Core mostly to
gho i; 9h5 ” 5 eat" 55.0 | sections of 1 inch and smaller.
Oh5 950 " 5 0710" 16.7
950 955 " a omer 6.7
955 960 " 5 113" 25.0
960 965 " 5 ‘15% 28.30 |
965 970 " 5 10" 36.7 |
970 915 " 5 ue 26.7 |
975 980 " 5 1'o" 20.0
980 985 ” 5 amy 46.7
985 990 " 5 240" hoo
990 994 " 4 12" 29.2 |
99h 999 " 5 kro" 80.0 |
999 1004 " 5 21g" B33 |
1004 1009 " 5 158" 33.3
1009 ‘1014 " 5 ent 41.7
YoU 1019 " 5 170" 20.0
1019 102k ” 5 ant 41.7 |
1024 1025 " 1 oof 75.0 '
1025 1030 " 5 13" 25.0 |
1030 1034 " 4 26" 62.5 i030 1075 |Nearly white to light buff
1034 1039 " 5 "310" 60.0 =| marble. Many fractures thinly
1039 1ohy ” 5 “hegre B33 | coated with MnOj. A few specks
lol, 1ok9 " 5 yr" 83.3 | of pyrite. Locally fractured
lokg 1054 " 5 yr 81.7 i parallel to core.
1054 1059 a 5 ett 41.7 |
1059 1050 l oto" oo |
1060 1065 " 5 3h" 61.7 |
1065 1070 " 5 3e 66.7
1070 1075 * 5 340" 60.0 |
3881 -19-




Hole 1A-U (Cont'd.)

| Distance| Core Core ii Petrographic description
Footage Core | drilled, |obtained,| recovery Footage j
From- To- size | feet | feet percent From= ij To-
1075 1080 Ex 5 o*10" 16.7 1075 1132 Pale buff marble. Many fractures
1080 1083 ” 3 oflo” 27.8 45 degrees to core dusted with
1083 1088 " 5 278" 53.3 Mn0p. Core broken 2 inches or
1088 1093 a) ett 41.7 less.
1093 1098 nL OS 213" 45.0
1098 1103 " 5 1" 38.3
1103 1108 ” 5 310" 60.0 i
1108 113 id 5 1 3%" 60.0 |
11123 1118 ” 5 | arg" 55.0
1118 1123 " 5 | 115° 28.3 i
1123 1128 ” 5 1710" 36.7 |
1128 1133 " 5 1'10" 36.7
1133 1138 " 5 Le" 23.3 | 1132 1138 Chiefly fine-grained quartz with
i considerable ZnS partly oxidized.
| | PbS in one place. Small amounts
: of fine, hard, pale-pink mineral.
1138 1uko " 2 | 086" 25.0 1138 1us7 [4/5 of core missing. Remainder
lito 1043 " 3 1 O'6" 16.7. small fragments showing quartz
1143 1147 " 4 ; othe 8.3 \ | and pale-pink mineral and small
i amounts of sulfides.
1147 1152 " 5 1'5" 28.3 | 1147 1151 About 3/4 of core missing. Re-
mainder is quartz with some of
H | the pink mineral.
i 1151 1152 Medium-grained, white to pale-buff
| marble - core broken.
1152 1157 sd 5 i 312" 63 3 1152 1195 Medium-grained marble-in general
1157 1162 "15 1 orl." 18.3 i lightly stained brown with Mn
ne 1168 " 1 6 ; ume 22.2 | and Fe oxides. Many fractures
1168 up nos 1 ue 31.6 F at different angles carry Mn 02
1173 1178 ni) | 1t5" 28.3 ' films. Core mostly broken to 1
1178 1183 a 0710" 16.7 | in.h or less. Only about 1/4
1183 1189 "1 6 | oto" 13.9 | inch seam of Mn 02 at 45 degrees
1189 1195 " 16 : 1o" 30.6 ! to core.

3881

- 20 -


Hole 2-S (Cont'd.)

| Distence; Core | Core Petrographic description
Footage Core; driiled, ; obtained, | recovery, Footage
From- i To- size feet feet percent From- To-

168 174 Ax 6 Set 84.7 166 219 Pale-buff and light-gray marble.
174 176 . 2 1'8” 83.3 Numerous limonite-coated frac~
176 181 ” 5 Ary? 98.3 tures and seams.
181 185, Ex 4 377" 89.6
185 180 ad 4 2'E" 66.7
189 19h ® 5 r. 100.0
19h 199 " 5 3'1" 78.3
199 20h " 5 AI6s. 90.0
204 209 * 5 Arye 81.7
209 214 an 5 Wis" 88.3
2uh, 219 " 5 yrgt 95-0
219 222 an 3 11" 63.9 219 229 Buff friable marble, much broken -
222° 226 " y 13". 31.3 only fragmental recovery of core.
226 229. " 3 ore 22.2
229° 23h. " 5 118" 33.3 229 268 Core mich broken. Recovered
23h 239. " 5 218" 533.3 fragments mostly light-gray,
239 2h3 “ 4 1'9" 43.8 fine-grained marble, locally
2h3 248 Md 5 17" 31.6 peppered with pyrite.
ahs 253 " 5 yrge 93.3
253 25k " 1 1'o” 100.0"
254 259 " 5 yron 83.3
259 264 " 5 are" 50.0
264 269° " 5 3'0" 60.0
269 eTh " 5 11" 21.7 268 288 Core badly broken. Fragments re-
27k 278 ” y en 53.1 covered show more or less
278 283 " 5 19" 35.0 quartz, limonite, and Mn0,.
283 288 " 5 uty" 21.7 282' to 288' breccia with

* quartz - locally shows -2nS..
288 293 " 5 1'a" 23.3 288 311 Core much broken. Recovered
293 295 ® 2 ory" 29.2 fragments are mostly medium-
295 300 " 5 or" 11.6 gray marble sparingly peppered
300 305 * 5 1°3" 25.0 with fine pyrite.
305.. --311 s 6 “ame 38.9

3881 -35-




Hole 2-S (Cont'd.)

j : Distance ; Core , Core i Petrographic description
Footage Core; drilled, | obtained, | recovery,|! Footage 7
From- To- size| feet feet __| percent | From- | ‘To-
557 560 Ex 3 {  1tg" 58.3 557 ; 567 | Light- to dark-gray, fine-grained
260 362 ; | 2 i xe 8 3 i limestone, locally friable and
5 S67 5 7” broken.
567 571 " 5 ! ame 46.7 567 591'6"| Light-gray, medium-grained lime-
571 576 " 5 i 46? 90.0 i stone with distinct gray bands.
576 561 " 5 j tg? 95.0 Rather soft and friable. Core
2 586 : 5 i oe 33 mach broken at 590 feet.
591 5 1 .
591 596 " 5 310" 76.7 || 591'6" 596'6"| Light-gray, medium-grained mr-
ble, somewhat porous.
596 599 . 3 Lye ped 5966" €21 Light-gray, fine-grained marble
599 60h " 5 510" 100.0 with thin bands of brownish
604 609 " 5 37" 71.6 gray - 70 degrees to core. -At
609 610 " 1 oto" O° | 609 feet, 2 feet plus of dark-
610 611 " 1 omen 33.3 gray quartz; 609 to 610 feet,
611 616 " 5 yrgn 95.0 no core; 610 to 611 feet, dark-
616 621 an) 4igt | 85.0 gray quartz, vuggy and badly
i : | ° broken, shows a little fine
‘ | pyrite.
@1 €26 a 5 wen | 93.0 621 626 | Light-gray to white, medium-
| grained marble - banding not
| : q pronounced.
626 631 “ 5 | Ato” 96.7 || 626 61 Light-gray, fine-grained marble
. y | with darker bands that are
| 1 i locally wavy. Bands (parallel
| | i : fl | bedding) stand mostly at 70
j i | | 4 | degrees to core:
| i ' : “| 631 | Bottom.
| : H i
1
3881 - 38 -


Co-ordinates

11,227", 11,0458.

Hole 5-S

Depth: 496 feet
Bearing: Due west

Petrographic description

Elevation at collar: 5,816 feet
Dip: 60 degrees
. i ’ Distance Core Core
Footage | Core; drilled, | obtained, | recovery, |! Footage i
From- | _To- 4 size feet feet percent _'! From- To-
5 |; io Lax i 5 ! 16" =; 30.0 i oO i 65
yo ' 1% ' © | 6 ; 2h | 38.9 | :
16 ao: TM | 5 17" 31.6 i
a} 86 EH fate | agg i
202, 0¢«3ls OS 1 36" | to.0
31 3605 "FOS ; 283" 5.0 i |
3600 j EM 5 i kre" 8343 '
a er | foe” | 85.0 |
rr ) a rn er) } 26" ; 50.0 |i
Gs a >  2to" | 36.7 |,
56 61 an) RB" | 98430
6. | 66 a) 1 3h) 66.7 |,
66 : 71 a) ' 5f0" =} 100.0 | 65 : 116
GL 1 76 nn) 7 1tg" ! 35.0: |
76 i 84 oo" 5 pee BL :
A: Sa ee > i
i: rs a boar | Bg 1
| 9 | MT 5 | ath | 55,0 | |
96 | wr | os 1 5 £33" | 6.0 ;
wr | we | Og sto" | 100.0 | |
106 | Mo-ae! " | haf | 3" | 7906 |
lo-i/f2; Wl |" | onlfa sO : 0 : |
ro ne fo 5g : 5fo" | 100.0
née; mw} " | 5 1 WBF i 9843 6 1-156
Wo} we fF oy Ss i WB" 933 |
we +: Bei flo" tl Ss © ato" | 56.7 |
BO} lB6S ES P ygt F933
136 aL ; hb 5 kro 5 95.0 |
UW ; m6 BS Atom 9500 H
146 i 151 io 5 ytot i 95.05 + :
151 156 " 5 yay 1.7
3881 - 47 -

Core consists of pale-yellow to
white, coarse-grained, Jeffer-
son marble. Split on numerous
cross laminae (bedding), show-
ing a little Fe oxides. Locally
much fractured and reddish brown
to small fragments.

Like above, except less broken.
Local fractures at 30 degrees
to core coated with Mn02.

Mostly light-gray, coarse-grained
marble. Locally yellowed by
iron stains. Below 152 feet
several fractures right angle
and 30 degrees to core, that
carry MnO films.




Hole 1-8 (Cont'd.)

H {Distance ; Core
= _ | Core |drilled, jobtained, recovery, Footage Retrogrannic Sesertzt ion
= = site feet: feet. percent t From, o>
in ix E 3 | er 33 2 | 187 | 201 | Medium-grained white Jefferson
195 109 " 3 rao” hear marble. Local fractures with
199 200 " 1 io 528 |) limonite stains.
Poo: 2OL . aes . 100.0
201 206 * 5 378" 83:3 |
206 Olt . 2 Rea 33 201 211 Fine-grained gray Jefferson marble
3 with dark-gray bands (biotite?,

on e16 " 5 378" etc.). Iocally friable.
De DOL * 3 et 8 3 | 211 239 Medium-grained white Jefferson-
DOL 2G " 2 5t9 : 3 } ocassional dark bands (biotite?
ee 2a . 5 Rion 5.0 | etc.). Locally friable. ,
231 236 ” ran 83.3 |
236 aba ” 5 P a3
aka 2hé " 2 235 65.0
ake oat , 3 , 25.0 239 271'k" | Aplite and granite.
ad 325 : 5 a'10 56.7 |

if 15" » |
255 ee " oa 354 |
ae ae ee
266 271 " Bar aes
271 275 w 1k 37" 30.6 | enue
pte Ae : : 3150 89.6 | 27h 285 Gray Jefferson - locally sheared
280 285 ° 3 hee ane | and gougy. Boundary of-
285 290 i 2 213 ie Oo | Maywood.
290 295 \ 2 ; 23, 5.0 285 290 Banded limey shale - Maywood.

7! 31.7 290 295 Fine-grained, sandy, Maywood
295 3 ” inn limestone.
ed 300 jm 2 ; tae 88.3 295 297 Yellowish marble.
302 30 ” : te 58.3 | 297 311 Alterating sandy limestone and
306 zu " 5 tee 29.2 ; White marble.
31 317 » 16 | 23" me | |
2°8 wah ff 312 313 Granite gouge ~ disseminated
i | pyrite.
3881
- 272


Hole 2-U (Cont'd.)

j Distance | Core |; Core Petrographic description
Footage ! Core | drilled, | obtained, : recovery, || Footage i
From-__To- size | feet 4 feet | percent {| From= | To- :
2680) b73fBk | 5 010"; 16.7 |} 268 ‘273 «| Small amount of core recovered in
| \ ' j | pieces less than 1 inch. Gray
. | i | | to greenish-gray marble.
2B | em | Ct ES ; 2" | 23.3 | 273 ' 278 | Like last above except less
i i i i | broken.
Hole 1-S
Co-ordinates: 11,316N, 11,0475 Depth: 972 feet
Elevation at collar: 5,812 feet Bearing: S 22° W.
Dip: 68° - 30°
Oo  ; 2-1/2) Nx | 28-1/2 f 0 | 28'6"| No core - disintegrated granite.
28+1/2; 30 ' Ax 1-1/2 1°6" 100 28'6" 7 White Jefferson marble mostly
30-1/2 35 " 5 1t6" 30 ' somewhat coarser than the
35 ho 1 oo" 5 ktg 95.0 Hasmark-fractured in places.
ho 45 * 5 4tgn 93.3 Fractures iron-stained.
45 dL " 6 513" 87.5
5 56 " 5 age 933
56 61 " 5 ; 45 88.3
61 66 ” 5 are 86.7
66 71 " 5 51" 100.0 .
wer 76 " 5 ats" 48.3 7 Th White Jefferson - several seams
. i | of Mn0, 1/8 to 1/2 inch thick,
{ ! 30 to 35 degrees to core.
76 81 nn) 35" 8.3 Tt 110 White Jefferson-locally brecciated
81 86 id 5 1 28% t 53.3 and cemented with limonite. At
86 91 ; * 5 i 5to" i 100.0 | 96 feet a 4 inch streak of
. | : i | breccia with quartz and
| { | limonite.
91 96 ; 7 5 1 Ae 91.7 “} a0 111 | Coarse gray Jefferson.
96 » OL sd 5 i 5tt 100.0 | |
101 106 " 5 1 59 | 400.0 l
106 uu m1 5 | hige on | |
3881 - 25 -


Hole 5-S (Cont'd.)

| Distance ; Core > Core HW Petrographic description
Footage | Core; drilled, ‘obtained, | recovery, | Footage
From- | To- i size! feet | __feet ;__bercent jFrom- | To-
373 378 | Ex | 5 hoary | 91.6 i H Typical Maywood with local frac-
378 383 | OM 5 Foto" | 35.0 | | | turing.
383 en ee) 1 3%" | 66.7 if °
388 | 3qn |” 3 , 28" | 36.2 i 388 ; 391 Only 13 inches of core. Frac-
| i j H| | tured and gougy. Last 3 inches
i i i i | | mostly gouge.
391 396 ne) , We" 83.3) 391 | 409 =} Same as above - last 6 weeks
396 hou 1 o" 1 5 : 5to" 1 100.0 ! H gougy.
i102 |
406 hop oo; * 3 / 17 | 52,8 ii H i
hog yu ; "1 2 oun | 54.2 i!hog : hag Same - at 411 feet is 1 inch of
4a os ee oe ee | gouge and at 415 feet is 6
416 yer 1 oo | 5 1tg" i 35.0 | | inches of gougy material.
yor j 406 " 5 15" | 28.300 |
426 431 " 5 1 46" | 90.0 i 4a 1 432. Fine-grained, dark-gray Maywood
| i | with abundant black tabular
| i i | | crystals. Maybe biotite. 6
| H | | | inches fractured, somewhat
| | | i ! gougy. -
431 435 ; y , ats" | Gob 432 | 6 inches fractured, somewhat
| | | H 1 H + gougy. ,
435 Aho a a) Por" 1 6167 432 i 6k} pypical Maywood, dark greenish-
i) fabs 5 (wa | 98.3 | ; | gray in places.
yuS | kg tm i Foams" 1 Gh | | t
Ang » Sh pom bogs ! yton ; 80.0 | i
45h 1 55 "od P oflo" §  83.30 | i
455 | M60 notos es ee sy a | i
460 i es fone | pi | : |
heh i 469 ,o" 5 + 2tgt i 55.0 46) i 6 inches fractured and gougy.
469 1 7h " 5 1 2t6r ' 50.0 hey ' 47h | ‘Typical Maywood - gougy material
i : : | i | at 468 feet.

3881 -50-


MY AN
i, SMU Gy

25 ran M
fe

OME I

Contour interval 100 feet

Ge :
a NG Og
Re iy SS Cites ;
Say a! =

=)
/

ASVNAALWNO = ABVILASL SNOwa sINOBaWD NVINOAZG @)NVINATIS NI

WIMaWWD NVINEWYD-3ad
8
z 3 5h » peg
fe} 0 x © 3 oy o x 8 _
Q gomt Be S ews ray =o m0e o§ . § ° a $M 5 Bet
fs (7s al glee WN 2 Nie HE Nes Zs Ne we he o SE Qik Gal
Zz > Kg te kS Oy Kyser = 35 ff c 9 xz @ 43 8% xf
2 ) € aE RADE [Git 8 cy 3 OF o 4; 2 @ Xs

[942 1 J2 BE eS ENS Pies NEE Zag NSE AS ABH ENS NG EE BED eS
a < a o@aceb 2 S8are LAGS Nine Zaire Nee 2 S eo ¢ EF a
Fn < 96 ES o =F woe Ff

ER = 5

xs

Adopted Fram U.S. Geological Survey

Figure 2. - Geologic map of the westerm part of the Philipsburg district, Granite County, Mont.


Hole 2-S (Cont'd.)
Distance Core Core : Petrographic description
= Foota, Core obtained, ; recovery, Footage |
‘rom- size feet i percent i
433 Ex 5 Aten 88.3 i Dark-gray, banded fine-grained,
| ?
Be " i ie | 190.0 | sandy limestone.
0
es . 3 310" | 100.0 Similar to last. Between 455 and
i 7 , y 315" ! 85 4 457. feet, core is peppered with
Neg . 2 2ren | 100.0 H specks of. a. black silicate
458 ” 2 Tg0" | Mur ' wostly exe, fin grained lime-
460 oi nh | a 4 ly Brey, e . ine
. 5 eae ; 100.0 i stone - in places light- to
165 ‘ 5 3 2" 6.3 | i dark-gray and very siliceous.
nile i 5 210 » | 100.0 | ' - ‘Occasional bands of pale green-
i , 5 4 lo" 96.7 | ish and yellowish-gray, appar-
1 ‘ 5 3110 i 76.7 i ently due to fine-grained
5 . 5-1/2 512 1 93.9 i silicates. At 477-478 feet
490-1/2 " 5-1/2 5" Be | many small laths of a dark
496 1-1/2 o*10" 55 i silicate (andalusite). Last 4
. i feet is a light-gray fine-
hgt-1/2 . 5 Sto! i 300.0 i rarer) marble.
‘ s! stly light-gray, fine-grained
502-1/2 . 5 5to" 100.0 limestone with darker bands
507-1/2 " 5 5t0” 100.0 (bedding) standing mostly at 75
512-1, 5-1/2 516" 100.0 degrees to core. Broken zones
zs |, [ae | Be wy 2, a 29 toe
523-1/2 " 2-1/2 ory" 23.3 H
526 ” 4 315" 85.4 1
530 " 4 ‘oF o i
53h ” 5 ye" 23.3 |
539 " 3 ore" 16.7 |
5h _* 5 510" 100.0
5uT " 5 ho" | 96.7
552 ” 5 4YIO" | 96.7
3881 737.7


Hole 4-S (Cont'd.)

{ Distance { Core i Core ik —fetrographic description
Footage ; Core ;drilled, | obtained, ; recovery, | Footage |
—Erom" To-__j _size | feet feet Percent | From .
6 !: @ |; Ar | 5 371" 7.3 | 6 100 Light-gray to pale buff Jeffer-
6 B |; " 5 | Arg 86.0 ij son. Locally fractured right
B 78 . 5 ary" 51.6 | angle to core.’ Light stains
78 H 83 ‘ | 5 2'8 53 63 | and specks of Mn0p. Locally
8 | (88 5 Aton 95.0 | ! cavernous and friable. | Broken
88 { 8 " 5 5'0" 100.0 \ i and gougy, zones above 93 feet
3 i 98 . 5 478" 3 3 i i and at 77 feet.
100 2 in 5.8 |
100 105 " 5 Ato" 96.7 | 100 110 (End of larger core.) Rock ‘same
105 1lo " 5 315" 68.3 | as last. 103 to 105 feet
H friable, light-yellow, specks
\ | | | i of Fe oxides. Core imch
| | ! | broken.
110 a5 | Ex | 5 510" =| 100.0 || 10 140 | Light bluish-gray to yellowish-
115 120 nn ie) 5'0" ' 100.0 | gray marble. Locally cavernous.
120 125 " 5 5'o" 100.0 |! A few fractures lined with Mn
ie 130 . 5 aes 1900 and Fe oxides.
30 135 5 3 T
135 140 " 5 ar 58.3
140 145 * 5 5%0" 100.0 1ho 145 Light-gray, medium-grained marble.
At 141 feet a few inches broken,
friable, and stained with Fe
oxides.
us | 150 " 5 ara" 98.3 | a5 174'6"| Light-gray, fine-grained marble
150 | 155 " 5 5t0" 100.0 || locally Peppered with dark-gray
" to" : j specks.
1% | ig | * | 3 so" | 30055
165 170 " 5 Ato" 80.0
170 175 " 1 5 itu" 38.3
50d] Bo GO EOS | ate 51.6 16" 180'6"| Light yellowish-gray, fine-grained
| i i marble. Locally fractured
j i i } parallel to-core and somewhat

| friable.

3881 - 43. -


5. Maywood formation: Silurian (7?) - 200 to 500 feet thick. Fine~
grained, moderately thin~bedded sandy limestone.

6. Jefferson limestone: Devonian - 1,000 to 1,300 feet thick.
Massive, blue-gray limestone. Near the granodiorite contact
it is altered to a white, medium-grained marble.

Ore Deposits

General

Most of the past production of manganese, zinc, and lead has been
derived from ores that are in or associated closely with east-west tension
fractures in the Hasmark limestone within 2,000 feet west of the
granodiorite contact (fig. 2). East-west tension fractures and northwesterly
striking faults between 2,000 feet and 4,000 feet to 5,000 feet. west of the
granodiorite contact are known to contain manganese or to be associated with
manganese replacement deposits, but none of them have been developed mich
beyond the prospect stage.

Some manganese has been recovered also from deposits that are in or
associated closely with bedding-plane faults between several of the
sedimentary formations, or from deposits that constitute irregular replace-
ments in the sedimentary formations adjacent to the granodiorite contact.

Most of the silver production of the district has been obtained from
the Granite-Bimetallic lode and from the Hope mine. The Granite-Bimetallic
lode is in an east-west fracture in granodiorite about a mile southeast of
the granodiorite contact; numerous other east-west fractures in the
granodiorite east of the contact have been prospected, but none have
yielded important amounts of ore. The ores of the Hope mine are associated
with east-west fractures in Jefferson limestone, but the ore bodies are
chiefly replacements along bedding planes.

Zinc-lead-silver veins

Many of the east-west veins in the sedimentary rocks have been mined
for zinc, silver, and lead. The width of the ore shoots ranges from a few
inches to 5 or 6 feet; the length of the ore shoots ranges from about 50
feet to about 300 feet. The ore fractures in granodiorite usually are
stronger than the ore fractures in the sedimentary rocks. The Granite-
Bimetallic vein is-the strongest vein in the district; its width, where it
was mined, ranged from 4 feet to 8 feet throughout most of its length; in
Places it was as much as 20 feet wide. Stopes on the Granite-Bimetallic
vein were almost continuous throughout a strike length of 4,500 feet and
throughout a dip length of 1,500 feet; no lessening of width or length
was apparent on the lowest levels. All of the east-west veins dip steeply;
usually they dip between 70° south and vertical.

3681 -7-


INVESTIGATION OF MANGANESE DEPOSITS
IN THE PHILIPSBURG MINING DISTRICT
GRANITE COUNTY, MONT.

By S. H. LORAIN

* «* # # «# «# « « «# Report of Investigations 4723

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

Work on manuscript completed January 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 4723.”

October 1950


Hole 1A-U (Cont'd.)

Distance Core i i
Footage Core | drilled, jobtained, recovery i Footage Petrographic deseription

From- To- size feet feet percent h From- To-
760 765 A sir aid
re thea Ax 2 Sige eaed Light buff Hasmark marble core.
ihe ca ox 2 3180 ‘2 3 j Much broken. At 724 feet, 2
15 180 zi 3 Bige be ° inches of Mn0p followed by 3
480 185 - 2 arts 3B inches of marble heavily
185 193 . 2 Orgt 3 3 stained with limonite. Rock is
790 795 " 3 1 onoM 2 locally cavernous and generally
15 800 o 3 tH | 25.5 somewhat iron-stained.
bos 3 , 5 of" 18.3
Bae Be : 5 orn 11.6
810 git " 1 one 33.0 |
816 821 m | 3 i" a
me oot : 5 1a a 21.7
826 Be7-1/2| qa tor er
fe7-1/2 Pers . i 1'0 66.7 826 831'7" | Core broken and largely wanting,

* " 7 shows some Fe and Mn stains.
831-1/2 | 835 3-1/2 ato 57-1} 631°7" 835 Largely quartz cavernous, “some

« ” H brown MnO,.
835 are , 3 110 36.7 | 835 836 Rich in MinOp «
as bn0 : 2 Mh 2167 835 geo Light buff Hasmark, core mich
br bo ‘ 2 ro a broken. A little Mn Stain in
855 860 " 5 oflo" 16 2 ' Places
aa ee
6 BS : 5 ath 46.7
875 880 " 5 ame 46.7
nn
Bee 3 ; 5 to) 10 i 16.7
8 95 ° 5 2'6 50.0
95 900 ‘ 5 3m" 61.7
900 905 ; 5 of10" 16.7
03 910 5 2to" 40.0
ois 915 . 5 15" ! 28.3 i
920 5 atm | 55.0

- 18 -








Hole 1-8 (Cont'd.)

Distance | Core Core Pet:
Footage Core | drilled, lobtained, recovery, Footage ° ae Sescrirtion
From- To- size feet + feet percent || From- —|—To i
t +

3 259 Ex 2 24° 0 ° 543 '6" 582'6"| Fine-grained gray to vhite marble
20 27 . 5 eye 83 | with bands of greenish material
351 3 . 5 _ 100.0 | and some garnet.

; 318" 91.7
566 pyen " 5 ' 100.0
571 576 " 5 3s + 100.0
576 580 " i t5" 85. I
580 585 "15 iran 83.3. |
pa 590 : 5 ae 88.3 582'6" 680 A visual inspection of these
236 296 ; 6 110 97.2 cores indicates them to be
ae 602 : 3 4N3 85.0 |! chiefly light to blue-gray
Qe ee : 2 Pai 100.0 || marble, fine-grained, and
bin fie ; iT . 91.7 ocassional thin bands of dark-
616 620 t ? 3/20 1.7 gray, some of them wavy, that
boo es ‘ 3i7 89.6 apparently represent bedding
@5 630 . 5 tom 100.0 and started at 35 to 50 degrees
630 6 “ 5 "9 " 55.0 to the core. This may be Red
as ee , 2 net 36-7 | Lion, but the classification is
dio ee " 5H « | not certain.
a6 | «652 " fe | 3am at

6! . i "
a a
660 665 “15 ue" 3333. |,
665 670 o 1s ips 80.0
670 675 « 5 | 3t6" 70.0
675 678 " 3 ; 2" | 97.2
pid er . 9 ake | Uke 680 690 Light-gray, fine-grained marble;
6 ean . 5 i 111 | 38.3 core much broken.
ea oT ‘ 5 yp btg" {91.7 690 703 Marble as above, wavy dark bands
oT 703 : 1 6 , ope | 84.7 | at 60 degrees to core represents
bedding.
3882 -30 -



Hole JA-U (Cont'd.)

Footage

From-

Core
size

: Distance
drilled,

Core
obtained,
feet

Core
recovery
percent

Petrographic description

Frori>

Footage

To-

hg

4h

459
Loe

469

Th

479

48h

489

3881

45h

459

Ley
hé9

ur

479
48h,

489

how

AX

”

”

feet
55

Intg"

tow

210"
3'0”
yr
3t0r

2'0"

ore”

95.0

83.3

40.0
60.0

86.7

fo}

70.

60.0

25.00

- b=

hogt6"
450

45616"

160
46s

469

yyy

479

46h

489 :

450
45616"

460

heh
469

479
4gh

489

hoo'7"

\
|
i
|

Yellowish Hasmark.. One inch with
solution cavities coated brow.
Yellowish Hasmark-a few fractures.
The most prominent ones at 45
degrees and parallel to core.
At 452'6" at 1 inch zone of
brown seams parallel to core.

Yellowish Hasmark, medium texture.
First 2 inches locally cavernous,
brown-stained, and partly gone
to sand.

Yellow to white Hasmark, somewhat
fractured and friable.

Yellow, medium-grained Hasmark.
At 465' 6" cavities partly
filled with limonite.

Yellow Hasmark. Numerous cavities
more or less filled with limon-
ite. A few fractures 45 degrees
to core, some parallel.

Grayish Hasmark, fractures paral-
lel to core. Last 2 feet
considerably broken. .

Grayish Hasmark, many seams and
fractures, lines with Mn02
films.

Grayish Hasmark, much broken,
ocassional fine grains of
pyrite. Recovered core shows
no Mn stain.

Yellowish Hasmark marble, frac-
tured locally, porous with
limonite stain.


Hole 2-U (Cont 'd.)

i Distance! Core | Core i Petrographic description
Footage Core | drilled, jobtained, ‘recovery i Footage
From- ms To- size| feet feet ; percent i From | __To-
119 | 12k Ex | 5 1t9" | 35.0 j} 119 ; WS | (Begin 7/8 inch core.) Light-
12h i 129 " 5 32" | 63.3 i | gray to white marble. A few
129 | -a34 . 5 2 ren 23 | fractures with films of Mn0p.
13) 39 5 1 1 1.7
139 | uh . 5 27 | 4.7 |
wh 1g " 5 26" =| 50.0 Uh i kg Core broken. Recovered fragments
i H are chiefly a. cavernous marble
1 | stained and filled with Mn09.
149 154 ” 5 193" | 25.0 19 1 15h Small amount of core recovered
i | consists of marble fragments
} : irregulerly streaked with
i i moe ( One ey of hard
i Mn02 (psilomelane).
154 156 id 2 Ve" | 58.4 154 | 197 Marble with nunerous fractures,
156 159 ud 3 1 16" | 50.0 i most of them at 45 degrees to
159 162 " 3 aie Mele dp { | core and coated with Pilms
1€@ 165 ” 3 253" | 75.0 | of Mn0z. Core mostly broken
165 pb 167-1/2 Ld ey 10" | 73.3 | to pieces less than 1.inch.
167-1 170 * a1, 1797, | 70.0
170 175 id 5 2toF =|! ho.
115 180 " 5 2to" |  ho.0 |
180 185 " 5 of1o" | 16.7
185 187 * 2 of1o" | 41.7 \
187 189 ” 2 oro" | 42.7 |
189 i | * | 5 ono" | 16.7 |
igh 197 " 3 1to"TM | 33.3 |
197 200 i # 3 Lto" tf 33.43 197 ! g00 | Fine-grained quartz. Cavernous;
! | ! | | i considerable ZnS and some PbS.
i | i | | | (Assay for Zn and Ag.)
3881 - 23-


10,9006 10008 Miog.e 200 & 1,300 €, - 9,900
ta 12400 6

S 12,300
- CHICAGO
S ‘SHAFT

12,200

EB~ Sreccig

12,100

oo] tiers: | “teat” Free" praca
vf ea-eo | 5 [iz.s]2.s0]es.o2
2 [er-10r] a [uz.6[ 1-70] 7026
3 ro1-103| 2 [19.3] 2:24] 69.08]
4 [103-105[ 2 [10-4 [1 87|71.52

D.D.H. No. 7-S — Section A-A’

3,900"

‘Sample | Length Percent
interval | teet_ (ma [Fe [ingot

3 [se-10af 5 [ees [267 [ere
D.D.H. No.1Q-S — Section B:

1,600

wa] Sonate Pareaat

Interval Fe {nso

@ [37-39 S[eeedl 2.1

7 [39-44] 5 | 04 [2.29] 7a76| 08

@[sa=a7] 3 }i1.1 |5.62[61.36] —

— ‘9[a7=a9 208 |s.11|sa6a] —

io [49-51] 2 | 60] 185 ]e296 —

u[si=sa] 3 | 20] 1609216] —

12 [54-595 | 39] 1.71 feoi2| —

13-59-64 | 5 | 15,5 | 2.07 |71.36] —

ia [ea=70| 6 | 268 1.98|91.00 —

1s-[70-83 | 13 [200 | 1-05 |6a6e| —

13-103] 20 22 [ase |rsi2| —

Ty fos=ia| 11 [21.4 [2.20 [s1.90] —

— ie iie=19| 5 ]26.1 |2.33|5656] —

wa] Semele = = 19 Jus=we[—s | 196 [2-25 [6232] —

THe eal eet teat ee 20 lize-27| 6 119.3 [2.04]66.10] —
D.D.H. No. 9°S - Section D-D' D.D.H. No. 6-S - Section C—C'

Figure 7. - Plan and vertical sections through drill holes 6S, 7S, 9S, and 10S.


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Hole 4-S (Cont 'd.)

: : Distance Core : Core H Petrographic description
Footage Core; drilled, | obtained, | recovery, ; Footage '
From- ;—To- ! size; feet | feet j_ percent jj From- Tor
280 285 | Ex | 5 ;  1to” | 20.0 276 285 Gray, siliceous limestone.
285 2900 : " ) 5 | orm | 11.6 285 290 Same as last. A l-inch streak of
| | | | | : herd, pink mineral (test for
| : | Mn?)
290 292 i | 2 | 013" ' 5.0 |! 290 292 Core missing except a few frag-
| | | | | i ments, including one of the pink
! i i : oo mineral.
rn] | atom | 43.3 |! 292 340 | Fine-grained gray limestone,
297 | 300; CO # | 3 aise | 80.6 locally banded with dark gray at
300 | 305 | * ; 3 3710" | 76.7 | 60 degrees to core.
305 =| 310 | 8 | 5 ate" 43.23 |
3100 ss EOS Are 95.0 |
315 1320 {| " | 5 213" 45.0 i
320 | 325 an) 38" 73-3 :
325 ; 330 | Mo 5 yrs" 88.3 |
330 ! 333 | fo 5 20, 100.0 |
335 3 i a) 50.0 i
340 | 345 | a) 5to" 100.0" |; 340 365 Fine-grained, dark-gray, siliceous
345° 350 | “5 AYl0" | 96.7 || limestone. Locally peppered
350 | 355 a) 313" i 65.0 with dark specks.
355 | 360 | "| o5 510" | 100.0
300 365 | OS 5108 100.0° jj | ;
365 ; 370 | 5 3'0 | 60.0 365 1 380 Like above. except now nearly lead
370 137 | 8 .| 5 } 372" | 63.3 : gray. Shows some brownish-gray
3751 380 OS rye | 86.7 | bands .
380 i) rn 319" | 93.8 | 389 | Medium-gray fine limestme.
384 | 389 yom G5 16"; 30.0 : Broken and somewhat gouged at
i | : : | 382 to 383 feet. Broken zone
: | H H about 386 feet, fragment of
| | | | | quartz showing a little pyrite
| H } | | recovered. .
389 i 394 $ o9 Fs | otg" j 35.0 | 394 | Broken and mostly missing. Some
! i i i ! : ' pieces contain irregular vein-
: : | Jets of white and very pale-pink
3881 - 45 ! carbonates.


Hole 1S (Cont'd.)
i ‘Distance ; Core i Core Petrographic description
Footage | Core | drilled, obtained, | recovery, { Foota

From- To- size feet feet percent Fron- To-

103 708 Ex 5 5° 100.0 703 708 First 2 inches lead-gray, fine,
siliceous rock. Remainder, fine
gray marble with browmnish-gray
bands.

708 713 " 5 i 5° 100.0 708 718 Fine-to rather coarse-grained

713 718 " 5 5¢ 100.0 marble with brownish-gray bands

\ (siliceous) at about 60 degrees
H 1 to core. —
718 723 ~«|:=C | 3 ‘5 ' 100.0 718 | 728 Similar to above - at 723'8" a
723 728 { wo 5 “5t 100.0 seam of gouge containing fine
| pyrite. At 725'8" small frac-
H tures at right angles-banding
cemented with fine pyrite.
| Another at 727 feet.

728 Bh " 6 516" 91.7 728 Bl Light-gray fine marble with a
Slight olive-green cast. At
730 feet a thin seam of pyrite.

Be _ BI ;  # 5 Ato" 96.7 Bl Bd Medium-gray marble with dark wavy

| bands, locally brecciated.

B39 Th5 * 6 593" 87.5 Bo 750 Similar marble with gray to

THS 750 * 5 410" 96.7 @reeriisi bands and occasional

| fractures.

750 - 755 io" 5 213" -45.0 = |! 750 776 Similar marble, with greenish-gray

1D 760 " | 5 5 100.0 bands.

760 165 "| 5 5* 100.0 i

165 TO : 2 3 ‘ 100.0

0 T16 583" (o>)

116 781 a) . 100.0 1776 816 Similar marble with gray to green-

781 (a nn) 3410" Ys ish-gray bands about ‘60° to core.

786 791 i; 5 5? 100.0 | Locally crossed by fractures and

791 76 | 5 5 100.0 | thin. greenish-gray seams.

796 Bort 8 5 Aeye 2

3881 -31-


Hole 1-S (Cont'd.)

‘Distance i Core Core fl Petro, i i
—_—_Footage___| Core jdrilled, jgbtained, | recovery, Footage graphic description
From- To- size feet feet percent From-__| To-
! " ;
ox 23 Ex g ae 43 +0 gh 933 | Bluish-gray.to tuff marble with
223 $28 : 5 Sau B32 some gray bands at 70 degrees
28 a3 a Reap 78 3 to core. Locally fractured.
5 10 96-7 At: 921'3" shows scattered
pyrite grains. At 923 feet, 2-
inch broken zone with a little
i " pyrite.
33 33 . é Bite 88-9 933 972 Mostly buff to pale gray or white
ous at ° z Rian an | marble, locally fractured and
351 oor “ é bee eR: gougy. At 953 feet a seam of
or 33 a 2 sti ab 7 quartz nearly parallel to core.
963 966 : 3 | i 33.30 |
972. A 6 Ua hd 72.2
Hole 2-S
Co-ordinates: 11,318N, 11,0178 Depth: 631 feet
Elevation at collar: 5,812 feet Bearing: S 84° wW.
Dip: 80 degrees : :
°O 21 el | 10) (¢) fo 21 No core. Used 2-r/ ‘inch bit
: through decomposed. granite for
AX casing. .
21 26 Ax 5 ar" 41.7 a1 41 Medium coarse-grained, grayish-
26 31 9 5 312" 63.3 white marble (Jefferson).
31 36 ae 5 370". 60.0 Locally broken and stained with
36. Ad ‘ 5 3'2" 63.3 iron oxides. Indistinct gray-
ish bands that probably repre~
sent the bedding show in
places.. These and some seams
of. yellow limonite.stand about
80 degrees to the core axis.
Occasional fractures with
films of MnOo. Broken zones
| with iron stain at 34-1/2 and
3881 33 37 feet.