UNITED STATES 

DEPARTMENT OF THE INTERIOR 

HAROLD L. ICKES, Secretary 

GEOLOGICAL SURVEY 

WALTER C. MENDENHALL, Director 

-0-

CIRCULAR 2 

-0-

COPPER DEPOSITS IN THE SQUAW CREEK AND SILVER 

PEAK DISTRICTS AND AT THE ALMEDA MINE, 

SOUTHWESTERN OREGON 

WITH NOTES ON THE 

PENNELL & FARMER AND BANFIELD PROSPECTS 

BY 

PHILIP J. SHENON 

WASHINGTON 

1933 
?3165 

CONTENTS 

Abstract . . . . . . . . . . . . • . . . • . • • • 1 

Introduction . . . • . . . . . . . . . . . . . . 2 

Field work and acknowledgnents. . . . . . . . 2 

Production of copper mines in southwestern Oregon . 2 

Squaw Creek district • . . . . , . . . . 5 

Loca tion and topography . . . . . . . . 5 

Geology . . . . . . . . • , . 5 

General feo.tures . . • . . . . , . 5 

Sedimentary rocks • • . . . . . 6 

Devonian or older schists . . . . , 6 

Carboniferous (1) rocks . . 8 

Stream gravel . . . . • . . . • . . 8 

Igneous rocks . . . . . . . . . . 8 

Greenstones . . . f • • • • 8 

Serpentine . . . . . . . . . 9 

Quartz diorite and r e l a ted roc ~s , . . • • . . • . . 9 

, ine s . . . . . . . . . . . . . . . . , . . . . , . . . . 10 

Pacific States Hines Co." . . . . . . . . , . . . 10 

Blue Ledge . • • • • • • • • • . • 12 

Silver Peak district . . , . . . . , 15 

Loca t ioi anO. a cce s • . . . . . . . . . 15 

Topograpr.y . • . . . . . . . . . . . . . • • 15 

Gene r a l .geology. . ...• 15 

nothan formation . . . . . , • 15 

Greenstone s • . . . . ' . , . . . , 16 

Ore deposits ... , ' .. .. ' . . . , . • 16 

Geographic distribution . 

Deposits south of Silver Peale • 

Deposits north of Silver Peak . 

Almeda mine . • . • • • • . . • • • 

Outlying copper prospects 

Banfield . . . . . 

Pennell & Farmer 

ILLUSTRATIONS 

f • • 

. ' 

Plate 1. Gcolo ic map of southern Orce on, howing loca tion of 

. 16 

. . , 16 

• , • 23 

• 24 

• • 35 

. 35 

• 35 

coppe r mines and p rospect . . . . . . . . • . . • • • 1 

2. Geologic map of the Squaw Creek di trict . . . . 4 

3. Cross sections through Blue Ledge mine . . 13 

4. ap of undergroUDi workings of Silver Peak ining Co. 

and Umpaqua Con~olidatcd ~ining Co. , • . • 17 

5. Plan of part of underground workings and longitudinal 

projection through workings, Almeda mine . • . . . • . . 25 

6, !ap of River level , Almeda mine . • . . . . . . • • . . • 32 

Figure l , Level 2 and 3, Pacific StateG ~ines Co •...••••. , • 11 

2. Cro s section through stope, Silver Peak ~ining Co. . .•• 19 

3. Photomicrographs of ores , Silver ~e~c mine • • • 22 

4. Almeda mine and Big Yank lode , • • • • • • . . . • • • • • 27 

5. Photomicrographs of ores, Almeda mine • , . • 29 
U. a. CliOLOOICAl. 8URVRV 

lllinS A11D PR>SPBCTS 

Sll ver Peak, Uapqua Coo2 P:,~~;.;:!rsraMield 431 f555555005;z(~~~/o07~ ~~L/ : :;;:>.-

3 Ban.rield 

4 Uapqua Copper Co . 

5 Green Woun ta.1n 

6 Copper Quaoo 

7 Al.aoda 

8 Copper tlng 

9 Booans& ll1ng 

10 Sbarp & tlcllnloy 

11 Collier Creek 

12 Oalt 

1.3 Chlsbol.ol 

1.4 United Cop!)<lr Co. 

15 Calu..et 

1.6 Bunker ll1ll 

17 ltidas 

1.8 Balley 

19 Chotco Copper Co . 

20 Reynolds 

21. Turner {Albright.) 

22 QuHn of 81'0D&e 

23 Co•bo7 

24 Paci.fic States IUJtea Co . 

25 Blue Leclie 

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Copper deposits in the Squaw Creek and Silver Peak 

districts and nt the Almeda mine , southwestern 

Oregon, with notes on the Pennell & Farmer· 

and :Banfield prospects. 

Ey Philip J. Shenon 

Abstract 

This report describes copper mines in the Squaw Creek district, 

in Jackson C01.mty, OreG.; tho Blue Lodge nine , nearby; tho Silvor Peak 

district, near 3!ddlo , Oreg.; tho Almada mino, ncar Galice, Oreg.; and 

some outlying pro~pects. Of the total reported production of some 

$2 ,000 , 000 from copper mines in southwest ern Oregon, the districts described 

are credited with about $181 ,000. However, considerable more production is 

expected from some of the mines in these districts whenever metal uriccs 

warrant operation. 

Metamorphic roc~s including schist , phyllite , and marble of Devonian 

age or older underlie most of tne Squaw Creek a~ea . These rocks are overlain by quartzite and argi~lite with limestone lenses, w~ch have bevn tentatively classed as Car~onifcrous(?). Torrace and stream gravel complete the 

list of sedimontQry rocks. The igneous rocks include medium and fine grained 

greenstones of probably C~rboniforous or Juracsic age and serpentine, quartz 

diorite , and rela ted rocks of Jurassic or early Cretaceous age . 

_The Pacific States Uines Co.'s property , in Oregon, and the :Blue 

Ledge mine, in California but tributary to Oregon, are the principal mines 

in the Squaw Creek district . Both de~osits occur as replacement bodies in 

schist . The layers of scl1ist are not- .verywhoro completely replaced but 

contain variable amounts of quartz and sulphides. Pyrite and chalcopyrite 

are the principal sulphides at the Pacific States mine , and pyrrhotite, 

pyrite, chalcopyrite, sp~~lerite, and galena at the Blue Ledge mine . The 

mino lized layers at the Pacific States property evidently contain a large 

toruw.ge of material that appears to be of very low average grade and some 

~11 shoots of betto?-grade ore; the :Blue Ledge mine contains a considerable blocked out tonnage of better-grade ore. 

The rocks in the vicin~ty of the Silver Peak mines consist of 

schists mapped by Diller as portions of the Dothan formation and greenstones of probab ~ Ju~ssic age . Both are greatly a ltered in the vicinity 

of the minos. rhe principal properti s of t ho istrict - the Silver Peak 

Copper and the Umpqua Consolidated mines - have partly developed tho same 

ore bodies. Tho ore bodies occur in highly foliated schist as irregular-

~ped masses of nearly solid ffil~phides and a s disseminated deposits. 

Copper-zinc ore of good g~ade carrying gold a d valued at about $73,000 

nas been shipped from these mines. !n addition conside rable ore is partly 

blocked out by underground openings. The principal ore and gangue miner~ls 

are pYrite , chalcopyrite, sphalerite, bornite, galena, chalcocite, tennantite, 

quartz , and ba rit e . Bodies of nearly solid sttlphido rc from 5 to 1q feot 

wide have been followed on tho lowo~ lovols of tho minos for a total 

ho~izontal distance of over 400 feet, and in at lea~t two places ore con-
7315&· 

t. nues beyond the pre sent workings. ca~se of the length of the shootsa~d the hypogene character of the mineralization on the lower levels. it is 

believed that the ore continles d.ownward for so.nc little dis.tance below the 

present lowest workings with but little change in t he mineral cont~nt. The 

Golden Gat e property , north of Silver :Butte, has produced some ore, but at 

present very little of minable grado is developed. Bands of schist with 

disseminated sulphides similar to those at the Silver Peak Copper and Umpqua 

Consolidated mines have been prospected, and one shoot of good-grade gold ore 

bas been mined. 

The Almeda mine is one of the most extensively developed mines 

in southwe st ern Oregon. It is credited with a production in gold, silver, 

and co per valued at about $108, 00. The ore is found in porphyritic 

dacite clo se to the conta ct with argillite. .A wide intensely silicified 

zone containing some gold and known as the Eig Yank lode contains shoots 

of better-grade ore. This bett er ore consists of the intensely silicified 

porphyritic dacite more or l ess ext ensively replaced by barite, pyrit e , 

chalcopyrite, galena, sphalerite, chalcocite, and covellite. Covellite 

has been added by supergene processes. The silicified zone at the Almeda 

]ine, known as t he Big Yank lode, constitut e s a tremendous reserve of very 

:ow grdde materia l that Should be given some consideration when metal price s 

y. The fea sibility of worki ng mat erial of this sort, even under favorabl e conditions, will depend largely upon tho r esults of very ca reful and 

comnl et e sampling. Mining a t the Almeda mine has demonstrat ed the occurrence 

o:' good- sized bodi e s of bett er-grade ore \7hich if mined with the lower-grade 

~i lici ied materia l would tend to raise the average metal content or which 

·mder more f avorable conditions might be orked in themselves. 

The Banfi eld and the Pe~Dell & Fanner properties are two outlying 

Jro spects that have been rather ext ensively developed. The Banfield property 

ha s ~ r e:portRd prod:uction of 52 tons cmntaining 10,059 poun s of copper and 

9 ounces of silver. .At this property chalcopyrit e and magnetite occur a s 

:rregul arly distributed stringers, grains, and bunches in greenstone; at the 

:-ennell & Fanner mine chalcopyrite cc0t1rs as streaks and grains along the 

_oliation in a dark hornblende schist. 

2 
73165 

Int reduction 

Field work~ ac£nowledements.- This paper presents the results 

of investigations i n several copper-mining districts in sout-l rrsetern Oregon 

by the United states Geological Survey, in coopercJ.tion with the state of 

oregon. (See pl. 1.) Two other copper-mining districts in southwestern 

oregon are described in another report .1/ The field work was done in 1930 

under the supert··s:': o:l of J .T. Pardee by the writer, who was assisted by 

T;unca.n Johnson and Aub-r.t:;y Walker in the Squaw Creek district and by Aubrey 

Wal ker in the Silver Peak district and at the Almeda mine. 

The Squaw Creek district, including the property of the Pacific 

states Mine s Co. in Oregon and the adjacent :Blue Ledge mine in California, 

was examined during part of August, and the Silver Butte district and the 

Almeda mine early in September. Although in California, the :Blue Ledge mine 

is more or less tributary to Oregon by reason of the fact that the nabn."8.l 

route to it passes through that state. 

The writ er wishes to acknowledge the cour-tesies extended by all 

the mining men uith ~hom tho field party camo into contact. In particular 

he wishes to thank Mr. C. C. Clark, of Medford; Mr. Harry Ear., of atkins; 

r. Carl Vanstrand, engineer of the Blue Ledge mine; Mr. &rry Sordy, of 

the Almeda mine; and Messrs. J. E. Reoves, J .K. Elder, and W. A. Bradfield, 

operators in the Silver Peak district. Special acknowledgments arc duo to 

. ~. A. B. Yatos, fonnorly geologist for tho Home stake Mining Co., for 

pen ission to uso maps of tho Almeda mine in this publication and for 

information regarding the oro bodies. 

Production of copuer mines in southryestern Oregon.- Including 

the gold and silver content, the value of the ore produced by the copper 

mines of southwestern Oregon is estimated at nearly $2 ,000,000, distributed 

as follows: 

Reported production of copper-mining districts in southwe stern Oregon 9:./ 

Takilma district 

Almeda mine 

: Gold : Silver : Copper 

:(ounces)(ounce s):(pounds) 

8 ,787 :7, 041,533: 

48,387 259,800: 

Silver Peak district: 

7 ,263 . : 

1,540 

228 

2GB 

12,203 41,450: 

Other mine s E) 732 81,192: 

a 

Estimated gross 

value 

$1,700,000 

108,000 

73,000 

20,000 

·--·------

Figures from data furni hed by Victor C. Heike s, of the U.S. Bureau of 

:ine u e 

pJ 

No records of ~~ small copper mines are available, but their output 

would probably not swell the total of the fourth group abo~v. e $100,000. 

Shenon, P.J., Geology and ore deposits of the Taki1ma-Waldo and :Blue 

Cree - districts, southwestern Oregon: U.S. Geol. Survey Bull. 846-B, 1933. 

3 
CIRCULAR~ PLATE 2 R. 3 w. 

EXPL ~NATION 

SEOIMii ROCKS~: 

Terrace and !c strewn~ ~ 

:-i ~bonife:rou.s(?) .;.(A~a:rut~ I I J ' {"' \ J . .... , . A J', /' ..lf' w.n·r . r ( " . v k.j...::.. ' Z" ' ' ' <I' ,Cf\ . . '...., • ' \J 0 WiUt lim.estoiu! l.enses) 1 \ \ f . K < , • f I A K ,-;o .... I. • ~1 , F • >_ • "" _ < ~ > , I. .. > . \ r l ~ 'Z r > L > ~ ~ 

GEOLOGIC MAP OF THE SQlfft W CREEK DISTRICT, OREGON-CALIFORNIA 

Devonian or older 

(sdtists, pl.l¥l.lites, and mf:V/;Ze:,~ 

flZ] Lenses oflimestone ~orotd:er) 

IGNEOUS ROCK~ 

8 . 

. Qu.a.rt:z dior'i te and related rock& 

[ill . . Serpentine 

[8Id ,.. 

> 

Gremst.one 

~~ 

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~~ 

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~~ 

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a:b 

01.) 

~~ ~~ ..., 
73165 

As a means of comparison, the deposits may be classified as 

follows in four g~ou s, based upon the character of the enclosing rock: 

1. Irregular-~~ped masses of ore in greenstone near sernentine 

contacts (~eon of Bronze, Wal0..o, Lyttle, and Mabel mines of the Taldlma 

district) • 

2. Irregular-shaped masses of ore in serpent ine near greenstone 

contacts (Cowboy~mine of the Takilma district and many· small deposits throughout southwestern Oregon). 

3. Replacement bodies in porphyritic dacite (Almeda mine). 

4. Replacement bodies in schist (Silver Peak, Squaw Creek). The 

Blue Ledge mine belongs to this group, but its production is excluded from 

the total because the mine is outside of Oregon. 

The deposits in greenstone have accounted for most of the production. 

One mine alone of this group, the Queen of Bronze, has a greater recorded 

production than the total of all tho other minos. Tho deposits in serpentine 

r.ank second, those in porphyritic dacite third, and those in schist fourth . 

Squaw Creek district 

Location and topography 

The Squaw Creek district, named after the creek that divides it 

into almost equal northern and southern parts (pl. 2), includes an area of 

some 20 square miles and is in the southwest corner of the Grants Pass 

quadrangle , in Jackson County, Oreg., adjoining the California line. It is 

reached by a good road from Jacksonville and Medford, respectively 25 and 

30 miles to the northeast. 

The district is drained by tributaries of the Applegate River. East 

and west of the valley of that stream the surface consists largely of rugged 

slopes. Within a horizontal distance of 3 miles the altitude ranges from 

2,000 feet to over .5,000 feet. Most of the slopes are bruSh-covered and 

difficult to traverse away from the beaten paths. 

Geology 

General features 

The oldest rock s exposed in the Squaw Creek district are schists 

of both sedimentary and igneous origin, of Devonian or older age. Overlying 

these schists are argillite and quartzite of doubtful Carboniferous ago. 

~nd and gravel of Quaternary ago fom narrow terraces and lowlands along 

the present streams. 

The oldest purely '-gneous formations consist of fine and medium 

grained rocks classified as greenstones. These and the Carboniferous(?) 

argi llit e and quartzite are intruded by serpentine, which in turn is intruded by qua rtz diorite and related rocks. 

5 
73165 

Sedimentary rocks 

Devonian or older schi st s 

several large areas in southwestern Oregon and northern California are underlain by schists and phyllites that lithologically are similar. (See nl . 1. ) However , because these a r ea s dre widely separa ted and because fo ssils ar~ absent or very 

poorly pr eserved , exact correlati on is impossible . I n northern California a group 

of rocks of these types are r egarded as pre-Cambri an by Hershey ~/vho described them 

as the Abrams and Salmon formations. In the Port Orford r egion Diller has tentatively referred to si ilar rocks as pre -Devonian, n.nd in the Riddle quadrangle he 

describes rockG of the same type which he assigns questionably to the evon ian.~ 

Winchell1/ has correlated the schists and phyllites of the Squaw Creek district with 

the pre-Cambrian (?) Abrams mica schi st (sedimentary) and Salmon hornblende s chist 

(igneous) of Trinity County , .. Calif. Consid.erable doubt i s entertained r egarding the 

pre-Cambrian age of these rocks, and they a r e here t Gntat ively classifi ed as Devonian 

or older . 

Within the Squaw Creek a rea the se rocks consist chiefly of schi st s and phyl lites 

but include a l so some lenses of limestone or marble and in places bodies of intrusive 

quartz diorite and other igneous rocks. Also locally the schi sts and phyllites contain seams and lenses of white quartz par allel ith the foliation ; and i n a few 

places, a at the Blue Ledge and Pev cific States mines, the chists have been partly 

or wholly r eplaced by sulphide minera l s . Probably the most ~bundant type of rock is 

a medium to dark green schist composed largely of quart z, epidote , and chlor ite . 

Rock of this tYPe occurs throughout the Squa~V Creek a r ea but i s particularly abundant 

in the eastern half. Anothe r abundant t yp e of schi st is compos d l argely of finegrained quart z with considerable sericite . Some of these rocks are extr emely finegrained and are most properly termed phyllites. All have mar ked schi sto se tructure , 

and some ar e much contorted . These hi ghly siliceous rocKs a re most abundant in the 

western part of the mapped area . Interbedded with the c:-chists are dark-green firegrained rocks with less pronounced schistose structure . They contain large cry.tals 

of gr een hornbl ende with shredded edges embedded in a groundrnass composed of quartz , 

ep iuote , zoisite , and saus uritic mat eria l. The t exture and compo ition of these 

rocks i s characteristic of some of the r ecryst a llized gr eenstones found elsewhere 

in southwestern Ore on . In addi tion to the rock described, at least one and 

probably seve ral layers of graph itic schist occur i~ the se ries. One layer is well 

exposed in Ca lifornia abou t 500 f eet up Elliott Creek from the mouth of Joe Creek . 

Graphitic schist i s also well exposed a t the Blue Led e mine and i n the NEt .ec . ll, 

. 41 S., R. ll W., about l mile east of the mouth of anzanit~ Creek. Near the 

we t edge of the a r ea mapped l enses of l~ estone are interbedded with schi st . The 

large t l enu occurs in the ,-., e c . 11 , where it crops out on the ridge northeast of 

Seattle Bar as a prominent l edge 200 to 300 f ee t wide . Two 5maller 

---·----- -----------

a/Hershey , O. H., amo hie formations of northwest rn Californi a : Am. Geologist, 

val , 27 , pp . 225-245, 1001 . 

~Dill , J . S., U. S. Geol . Survey G ol . Atlas, Port Orford folio (no . 89) , P • 2, 

1903 ; U. s. Geol . Surv y Gcol . Atla ., , Riddl e folio (no . 218), P • 2 , 1924 . 

i/Winchell, A •. , Pe trology and miner al re sources of J a ckson and Josephine 

Counties, Oreg .: inc r a l r esource s of Oregon , vol . l, no . 5, PP • 37, 38 , Oregon 

Bur . ines and Geo logy, 1~14 . 

6 
73165 

lenses wore mapped near tho mouth of Manzanita Creek. All have the same 

attitude as the schists. The limestone is b-luish gray to white and in most 

places :has a we~l banded structure defined by the presence of :n:: ous small 

flakes of graph~te that have tended to concentrate in layers. According to 

Diller£/ the largest of three lenses appears to overlie the schist. However, 

the rocks above and below this limestone lens are so similar to the other 

schists that they could not be separated by the writer on a lithologic basis. 

Furthermore, the two smaller lenses on Manzanita Creek are well within the 

schistose formation. In general, the schistosity of the rocks dGscribed 

above strikes east of north and the prevailing dips are 400-5QO . .-'J. Locally, 

however, intense folding has taken place. 

The schists exposed within the area mapped are, in part at least, 

of sedimentary origin. The graphitic schists and the very highly siliceous 

schists and phyllites are undoubtedly metamor¥1osed sediments, and possiblJ 

the quartz-epidote-chlorite schists belong in the same category. Tho darkgreen, loss schistose rocks containing hornblende arc most probably of igneous 

origin and may represent either intruded b~dies or flows. The schistose 

group at Squaw· Creek agrees fairly well lithologically with the Abrams mica 

schist as described in its t;y-pe locality, but the thick series of hornblende 

schists described by Hershey as the Salmon formation apparently is not present. 

The hornblende schists that have been found in the Squaw Crock district arc 

int erbedded with siliceous schists and phyllites and are not ,mown to occur 

as a distinct unit. Like the schist series in the Squaw Creek district/the 

Abrams schist in northern California includes lenses of blue crystalline 

limestone and white marble as uell as graphitic schist. HerShey describes 

the graphitic schist as occurring with actinolite schist at the contact between the Abrams and Salmon schists. In the Squaw Creek district the schists 

dip to the northwest, and therefore the Salmon hornblende sChist in its 

normal position should, if present, lie northwest of the schist t l1at is 

correlated with the Abrams mica schist. A thick series of hornblende schist 

was not found to tho northwest of the quartz-sorici to schists and phyllite s. 

As a r esult of study of the relation between cleavage and banding in certain 

slates associated with the schists near the Blue Ledge mine Winchell§} has 

~ge sted that the series is overturned. If so, schist corresponding to the 

Salmon hornblende schist may occur to the east of the schists exposed in the 

Squaw Creek district and may be represented by tho quartz-epidote-chlorite 

schists described above, which lie immediately below tho graphitic schist 

near tho mouth of Joe Crock . 

The age of the schists is not known. The degree of me tamorphism 

suggests that they are olce r than the argillite and quartzite which adj oin 

them on the west and north. ~rtz diorite and peridotite intrude both 

argillite and schists, and therefore if both were of the same age, they 

should not show so marked a difference in degree of metamorphism. The age 

of the argillite beds has not been determined, but they belong to a belt 

of rocks C.Jiller' s fourth boJ/- )7_/ that extends northward beyond the Little 

Diller, J. S., Unoral r esource s of southwest ern Oregon: U.S. Geol. 

SUrvey Bull . 546 , · 15, 1914. 

§) 

7J 

Uinchcll, A. N., op. cit. 

Diller, J. S., op . cit. (Bull. 546), · 16. 
73165 

A legate River. Poorly preserved fossils have been found in limestone beds 

p;ociated with these rocks, and according to Diller they guegest that this belt 

a~ rocks is Carboniferous. Therefore, as the schists aPPear to be older than 

~he argillite and qu.artzi te, which are of doubtful Carboniferous age, they may 

be tentatively referred to as Devonian or older. 

Carboniferous (?) Roc~s 

Argillite and quartzite crop out north and west of tho schistose 

rocks described above as Devonian or older. Of tho two, argillite is tho 

more abundant. Whore fresh it is prevailingly dark gray, but along fractures 

it is stained brown by oxidation .products. It coroL1only lk~s a platy parting 

but no well-developed schistose structure. Noar-uiC-contacts with quartz 

diorite , tho argillite is in many places altered to an epidote-bearing rock. 

The qw.rtzito is white or pink and relatiyely pure and ncar quartz diorito 

intrusive bodies is largely recrystallized. In places for example, in soc. 

36, T. 40 S., R. 4 W., just south of French Creek the argilli~e and quartzite 

are much contorted. Limestone lenses occur with the formation. One small 

lens crops out on the west side of the Applegate River in sec. 2, T. 40 S., 

R. 4 W., and others were noted just west of the mapped area. The limestone 

lenses belong to Diller's fourth belt, for which poorly preserved fossils 

suggest a Carboniferous age. 

Strbnm: Gravel 

Stream gravel occurs along the present streams and on remnants of 

terraces 15 to 50 foot above the present streams. Tho terraces arc well 

exposed along tho road between French Crook and Copper post office. Tho 

gravol is composed mostly of poorly sorted but \loll-rounded boulders of 

schist, quartzite , quartz diorite and related rocks, pegmatite, and quartz. 

Elevated terraces arc common in south~cstern Oregon and r oprcsont different 

stages in the uplift of the Klamath Mounta~ns . In some places they have boon 

mined for their gold content, but so far as kno\ln those in tho Squaw Crook 

district have not been worked. 

~1o gravel along tho present streams is similar in composition 

to tho terrace gravel. It h~s been mined at several localities in tho Squaw 

Creek district. 

Igneous Rocks 

Greenstones 

The term greenstone has been applied in southwestern Oregon to 

highly altered medium to fine gra.ined igneous rocks which because of the 

Presence of secondary chlorite, hornblende, and epidote shorr a green color. 

Rocks of this type are abundant in the northern part of the Squaw Crook 

district and occur interbedded with the Devonian or older schistose rocks. 

The greenstones differ ·somewhat from place to place within the area mapped, 

but most of them may be included in two general types, one of which is 

modi~graincd, the other fino-gr~ncd . Both arc dark green, and, as shown 

by the microscope, both have undergone considerable recr.ystallization. The 

feldspars are almost entirely changed to fine-grained saussuritic material, but 

8 
73165 

orne unalte red areas have the composition of andesine . Hornblende is abundant as 

;arge gr o.ins with shredded borders n.nd as small flakes throughout the groundmass . 

Chlorite , sericite, epidot e , zoisite, tre nolite , and serpentine a re present in 

ariabl e a~ ounts. -~aly se s of rocks of h~se types from other districts in s o lthwcst ern Or agon show t hat they arA nmch morE: ba ic than is indica ted by t he composition of the feldspars . In the Takilma- Vlaldo district ,.£/ for exar:Iple , analyses 

5 ow t hat both medium and. fine grained greenstones with sodic feldsp rs have the 

composition of basalt. The greenstones of the Squar Creek district a re very much 

liKe those near Takilmn.; hence it is likely tl.J.a.t tho fine-gra ined greenstones a re 

roetabasnl ts and the :nedium- g r a ined greenstones . ot o.gabbros. 

Serpentine 

Serpentine underlies sever al relatively small and irregular-shaped areas in 

the Squaw Cre~k district . The rock is simila r to tl e serpentinized peridotite in 

other parts of south' este rn Oregon. The origin.q,l olivine and pyroxene a re largely 

altered to a fine - grained felted agg e· te of serpentine . However , some residual 

patches of the original minerals r emain in most of the serpentinized bodies. Dise.i nated chromite and magne tite a rc fairly abundant. ·ear some i!'ltrusive contacts 

~ nophyllite occurs l arge ly as radiating fibers . Exposures of this mine r a l are 

found a long the roa d on the cast bank of the Applegat e River just s outh of the 

al ifornia line . Tbin se ctions show tha.t some of the c;,nthophylli t e has developed 

directly from olivine . The olltcrops of anthophyllite tr..at we r e exc:unined a re small 

and considered a s asbestos a r e of poor quality a nd, for the present a t l east, of 

no economi c value . 

The age of the serpentine in the Sq1m~ Creek district was not closely fixed . 

·t intrudes the a rgillite of supposed Carboniferous age and is cut by quartz 

diorite . The age of the sernentine elsewhere in south estern Or egon has been 

determined as late Jurassic ~r early Cretaceous ~/ 

Q;uartz diorite and r elated roc_cs 

.any large and small a reas in ~outh~est rn Oregon are unde rlain by quartz 

diorite or r elat e d rocks. These rocks e.re r e lati vc:ly of economic importance , not 

only be cause s ome may be utilized for building stone but also b e cause many of the 

ore deposits in outhwestern Oreg on are believed to be closely associated with 

them in origin. 

The quart z diorite in the Squaw Creek district is normally a light to dark 

gray rock of fairly coa rse texture . In some places border phases are much darker 

and coarse r-gra i ned. 1Iumerous irregular masses a.nd dikes of aplite and pegmatite 

c t the quartz diorite . These dikes are well exp osed along the Applegate River 

at the mouth of Squaw Creek, ~here the streams have ~tripped the overburden from 

he bedrock. The normal rock i s composed principally of feldspar andesine, green 

ornblende , quartz, biotite, orthoclase, a nd megnet ite, named in the order of 

abundance . The roc~ in general is quite free f rom hydrothermal a lte ration or 

~amot ermal effects. 

§} Shenon, P .J., Geology and ore depo sits of the Takilma- Waldo district, 

regan; U.S . Geol . Survey Bull. 846-B, 1933. 

VDiller, J.S., U. s. Geol. Survey Geol. Atlas, Riddle folio (no. 218), 

p. 4, 1924. 

9 
73165 

The ~~rtz diorite of the Squaw Creek district intrudes Carboniferous (?) 

argillit e and quartzi tc as well as serpentine. Elsewhc~re in southwestern Oregon 

the age has been fairly well fixed as late Jurassic or early Cretaceous.lQ/ 

Mines 

Pacific States Mines Co. 

Location and ac cess. - The property operated by the Pacific States Mines Co. 

is in se c. 5, T. 41 S., B.. 8 W. , Willarne tte meridian, along Squaw Creek about 32 

nes southwest of Medford . The road is narrow but serviceabl e and follows a 

grade for prac tically its entire distance. 

ost of the development work has been done on the Gold Nob , Pa cific, and Iron 

Hand cla.ims , named in order from east to west. Three short tunnels and several 

surface trenches have bee 1 excavated on the Gold Nob claim. On the Iron Hand, in 

addition to many surface trenches, two tunnels, 80 and 90 feet long, have been 

opened. The lode on the Pacific claim is developed by three adi t levels and 

several surface cuts. The principal level, No . 3, includes a crosscut 320 feet 

long from which drifts that aggregate 350 feet have been driven northeast a nd southest . (See fig. 1). Level 2 is 150 feet long and is 95 feet above level 3 and 

connected with it by an inclined raise. Level 1 is 32 feet long . In August 1930 

development work was confined to drifting on level 3. 

The ore at the Pacific States r.1 ine occurs as replacement bodies along certain 

beds of the schist. Several beds of schist distributed through a zone nearly a 

ile ide have been partly prospected , and all a r e more or less mineralized. The 

schist beds strike from N. 30° E. on the Iron Hand claim to N. 65° E. on the Gold 

ob claim and dip 40°-65° 1~ . In some places the schist has been l a rgely r eplaced 

by quart z and sulphidec ; in other places, even within the same bed, the sulphides 

are spar se ly distributed. The more intense ly mineralized beds range in thickness 

from a f ew inches to over 40 feet and consist of highly a ltered chlorite schist 

containing considerable quartz , some epidote and sericite, and sulphide i n va ryir.g 

~ount . In general the thicker beds are l e ss miner a lized. 

Pyrite and chalcopyrite a re the principal sulphides , a nd sphalerite is present 

i ll amounts. Pyrite is by far the most abundant sulphide except in some 

laces--for example , in certa in beds a t the f a ce of the south drift on l eve l 2, 

here it is exceeded by l~~l copyrite. Polished surfaces clearly show t wo stages of 

i eral iza tion . Quartz and pyrite were deposited first , a nd a fter they we re 

fractured , quartz, chalcopyrite , and vphalerite ~e e introduced. The zone of oxi-

~t io n i s very shallow . Fresh-appearing sulphides occur a few feet beneath the 

vurface . 

Economic consider~tions .--The ore a t the Pa cific Sta t es mine has been formed 

by replacement of schi tose beds of devonian or older age . Severa l beds have been 

mo e or lees mine r a lized, including three th~t have been partly prospected on the 

Gold ob claim and a t least three on the Ir on Hand claim , as well as seve ral beds 

e~osed by the ~c ific wor k ing s . In s·ame pl a ces chalcopyrite is pla inly visible, 

10

/ Diller , J • S • , op • cit • (Riddle f o 1 i o ) , p • 4. 

10 
50 

Some d issem inated .. ::; ... · 

su lphides,mostfy pyrite 

0 ~o feet 

py r ite 

N 

D issem inated sulph i des in sch istose rocks 
73165 

ssociated with pyrite. These mineralized beds ev ide ~tly conto.in a large tonnage 

~f ore, but the material appears to be of very low average grade . ~ne numerous 

trenches indicate that the beds have been sampled at the surface by the operators, 

but the results are not available to the writer . The parc:..genesis of the minerals 

shows that quart z and chalcopyrite were introduced along fractures into schist 

containing an early gene ration of quartz and pyrite. It would, therefore, be expected tbat chalcopyrite would tend to concentrate a.long the most permeable zones 

of fr acturing . This is bdrne out by the field evidence . The higher-grade chalcopyrite ore occurs in shoots, but the earlier quartzl)yrite oro i s much more 

@iform and widesp r ead . The deposits are similar in type to thos8 a t the Blue 

Ledge mine and at Silver Peak, in all of which sulphide minerals have replaced 

schistose beds. However, a t Blue Ledge and Silver Peak the replacement has been 

ore complete and the ore mine r als occur in g reater variety and abundance . 

Blue Ledge 

General features. - The Blue Ledge mine is in California about 40 miles southwest of Aedford and 3 miles south of the Oregon line, on Joe Creek, a tributary of 

the Applegate River , at an altitude of about 4, 000 feet. The mine is developed 

bymore than 15,000 feet of drifts and raises, including a series of adits that 

pe etrate a cliff-like slope , and a winze which ext end.s 210 f e et b el ow the lowest 

adit and from which levels have been turned at 100-foot intervals. These workings 

e~lore the deposit for a vertical distance of about 800 feet and a horizontal 

distance of about 2, 000 feet. In addition the r e are about 15,000 feet of diamonddrill holes. 

The Blue Ledge mine is owned by the ~exican Smalting & Refining Co. and in 

1930was under option to Dr. J. F. Reddy, of edford . 

Ore deposits. - Two types of ore have be en found ~t the Blue Ledge mine - a 

low-gr ade pyritic ore and a better-grade coppe r-zinc ore . Both types occur in 

schist as large lenslike bodies, which generally parallel the schi stosity but 

locally cut a cross it. 

Diamond-drill holes and some crosscuts have pa rtly eA~lored a large ma~s 

deGcri bed as a 11 p yri tic ore body" but, bucause the workings in this part of the 

ine we r e closed in 1930, this body was not seen . Cross section by W. B. Robinson 

show it to be over 30 feet wide in places and according to Ar . Vanstrand, engineer 

charge of the mine i n 1930, it contains 1 .5 percent of copper. 

~ne lenses of copper- zinc ore range in length from a few feet to several 

hundred feet and in lidth from a few i nche to ove r 12- feet . They are not solid 

sulphide ma ss s but include many fragment or "horses" of the wall rock. The 

stri -e of the 1-.Jnsn r anges from . 20° E. in the north end of the mine to due 

orth in the south end and a v e r e1gec about :r . 13° E. Dips also vary from place to 

place but average about 600 W. ThE. chist nclosi!lg the ore is continuous with 

that in the Squaw Creek district . The footwall i dark-colored quartz-hornblende 

:;chi st . In places a t least, wher~ it could b e obs e rved, the hanging wall is a 

white sericite schist known locally as 11 s ilvor schist , 11 which contains numerous tiny 

lenseG of sulphide minerals. In s ome place~ the wall rocks, especially the 

~e ricito schist , conta in large cubes of pyrite . 

12 
25 0 

LCVCL 6 

L£V£L I 

Ul.V.L ol (tNT~"NICDIAT£) 

LLV£1.. 4 

te feet 

~ LCVCL 10 

\ 

\ 

\ 

\ 

\ 

\ 

DIAMOND- DRILL lfOL£ til 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

\ 

DtANOND-DRILL lfOL£ 3<3 

L£V£L I 

EAST-WEST CROSS SECTIONS THROUGH BLUE LEDGE MINE 

CIRCULAR 2 

'- 8 

::"f~\ 

PLATE 8 

Coppe~ r-zinc ore 

8 

Py rite ore 

.... 

~ 

It 

Clt> 

,., 

~lei () ~ \ () 'l.l: 

(i 
73165 

The chief ore minet.als are pyrite, pyrrhotite, chalcopyrite, 

pbalerite, and galena, and the gangue is for the most part altered wall :ock and quartz \lith s.oma ca. lei te. Winchell 1JJ reports primary tourmaline 

and biotite. The proportions of the sulphides vary from place to place . 

polished sections of specimens more or less represent~tive of the copperzinc ore show that pyrrhotite constitutes more than 50 percent of the sulphide 

~ncrals . sphalerite is. next in abundance and makos .up about 25 to 30 percent. 

~lcopyrite composes most of the remainder, and only a very small amount 

of galena is present . The texture of the aggregate indicates that these 

~lphides were deposited one after another, probably without any lapse in 

the process. Pyrrhotite appears to be the oldest of the four. Veinlets 

of sphalerite were not observed cutting it, but its bovndaries are much 

corroded at the sphalerite contacts. Veinlets of chalcopyrite cut both 

wrrhotite and sjhalerite. Galena appears to have formed somewhat later 

mn chalcopyrite, although there is probably but very little difference in 

age betrreon tho two minerals. 

The sulphide or9 has boon partly oxidized to a depth of about 50 

""eet . Limonite~ malachite, and somo azurite and black ozide are tho more 

cormnon oxidation products. 

~mic considerations.- Evidently a considerable tonnage of ore is 

·clocked out in the Blue Ledge mine . and in addition nru.ch ore is stored in 

umnps . Assay maps furnished by Mr. Carl Vanstrand indicate that more than 

50,000 tons of ore is available in the mine, containing 4.4 percent of copper, 

2,0 percent o~ zinc, 0.125 ounces to the ton in gold., 5 to 6 ounces to the ton 

.n silver, .and some lead and that about 50,000 tons of ore containing 3 .3 

percent of copper is stored in the c:urnps. 

As Shown by maps and cross sections the ore shoots tend to pinch 

itlt just above tunnel 4. (See pl. 3.) A !Ik'""f' of the level run from the winze 

200 feet below tunnel 2 shows ore with an average width of about 1. 77 feet 

and a metal cont ont of 2.38 percent of copper, and 0. 02 ounce of gold and 

·.002 ounces of silver to the ton. This widening in the vein on this level 

offers some encouragement for deeper exploration, particularly because th~re 

appears to be a barren zone both immediately above and below level No. 4. 

The Blue Ledge mine contains a considerable tonnage of ore whiCh 

will be valuable when metn.l prices again rise high enough to offset tho costs 

of mining and smelting and the rather high cost of transportation. AccorC.ing 

o .r. Vanstrand the truckage charee to Medford is $3.50 a ton and the railroad charge from Med£b.rti to the smelter at Tacom9. $5 a ton. Evidently these 

~rges would practically prohibit the Shipment of the crude ore except durng periods of exceptionally high metal prices. The deposits stand at steep 

angles, and the wall roc~s are strong; hence very little timber is required, 

nnd above level 4 the cost of extracting the oro would probably be moderate. 

e ore ~~auld not be particularly difficult to concentrate, and consideration 

~ould be and no doubt has been given to this means of r~ducing the trans-

:portation charges. 

w 

ITinchell. A. N., op. cit,, p . 130. 

14 
Silv·\r Peak district 73165 

Location and nccess 

The copper deposits of the Silve r ~k district lie in the southern 

ps.rt of Doug1a s County, Oreg . , in sec s. 23 and 26, T. 31 S. , R. 6 \V . By 

air line the mines are about 7 mile s directly south of Riddle, a shipping 

uoint on the Southern Pacific Railroad, but by r oad the distance is about 

miles . The r oad is steep and ~~rrow but except during stormy periods is 

readilY p:1ssable . 

Topography 

The surface of the Silver Peak istrict is made u p Chiefly of tho 

steeply sloping ~ides of ~ny va lleys and inte rvening nn.:r row ridges with 

fo.irly fla t tops. Altitudes rango from 4 ,000 foot on Silvor Peak to loss 

than 2 ,000 f oo t in somo of tho valloys sl i ghtly more than a n ile distant . 

s:lvcr Peak is tho highest p oint in tho imrnod.i a to region, a!ld from it a 

s lcndid view co.n bo lu.1.d of tho surroU!:ding country. Tho valley slopes 

are generally covorGd with don so growths of timber and underbrush , and 

hence most of tho trails and ron.d~ tend to follow tho Tiidor valleys or 

ridge top s. 

Tho t h roe princiFD.l streams t.hat rise on thn slopes of Silver 

?ca.\:-- the West F.c rk of Canyon Crook , Middle Creek , anrl Ru.ssoll Crook--

:low re spectively eastward, westwarcl, a nd north\ ard. This radial drainage 

~tte rn is of small extent, however , because a ll three streams join t he 

Umpqua River. The streams have dissect ed tho r egion to a stc:.ge in which 

the canyon areas prevail over the rather narrow divi des, an , tho topo5 raphy 

of tho r egion can therefore bo doscriboa a s nature . 

General Geology 

The rocks in the vicinity o: Silve r Peak belong principally to the 

othan formation, described by Dlller, 12/ ana to a g roup of - i ghl altered 

igneous rocl-'.:s of seve ral types which arc termed g r eon st on s b ecause of t hci r 

prevailing green color. Tho contact b e tween tho Dot h n rocks and tho greenstone s is irregular but in general otrikes nvrthoa · t and , in the vicinity 

of Silv r Peak , dips at stcc:;;:> ~p; los to the southeast. No q,.~,.- :'tz diorite 

or r el ated intrusive rocks are known to crop out i n tho iB!Ilodi a to regi on. 

Dothan Fo~tion 

Tho Dothan fona~tion, of Jurassic a c o, in tho Ri ddle quadran£10 

co si ts pr edomin.D..: .. tly of san.d st 1 o but incl 1 ·o s also shu.lo , cone;l omorato, 

u d chert . The strata. are 11sually t h in-bee a.ed , yet in pl ces b ods about 

100 feet thick are f ound . Snr.o of the r ock s nave a schist ose structure and 

mny of them c nntain veinl ets of quartz par a llel t0 the s~~st sity. ~1e 

sandstone is r:;ray and rTeo.thc rs to a ~rellowi sh broun and whore not strone;ly 

motamor crsod broo.ks with a somewhat roueh surface . Tho shale is usu:J.lly 

ray to darl'· r;ray o.nd. is distinctly sl ty. Tho conglomo roto, which occu rs 

in thin bedc:- , contain s p ubbles t~w.t a ro p rodomina'1tly siliceous. Tl1o chert 

f nns small l entils. ' 

12 

Diller, J. S. , U.S. Genl . Su.rvoy Go 1. At la s , Riddle folio (no . 218) , 

p. 3, 1924. 

,~ 
73165 

Near the Silver Peak mines the Dothan formati on i s composed principally of 

dark-graY . to lmost black thin-bedded schist and highly a ltered fine-grained 

agillite . Many of t he Dothan rocks a r e so completely a lte r ed that it i s difficult to diffe r entiate them i n t l e f i eld from the a l t er ed gr een tone s . ear the 

ore bodi e the chi t i . bl eached to light gray or almo~t !hi te and , becau e of 

he abundanc e of eric i t e , ha a t a lcose app ar nee . In aC.di t i on , the ore- bea ring 

schi (.' t commonly conta ins con iderc ble qua rtz , barite , 2.nd disseminated ulphi des . 

rike faults a r numerous, orne of which agree with the dip of the forma tion and 

e do not . The schist lies betv-een da r k- gra y rocks that are shom by the micoscope to be very f i ne gr a ined, h i ghly a lter ed a r gillites composed l a r ge ly of 

all rounded quartz grai ns in a fibrous groundmass of se ricite and chlorite . The 

z gr a in a r e sma ll, on an ave r age about 0 .135 millime ter a cross , and many a r e 

ar ly r ecry t a l l ized . In tho a r . i l i t e rea r the ore bodie ther e a r e numerou s 

grain of di ssemi nat ed sulphide s . ,. 

Greenstone s 

Irregular bodie s of gr eenstone are wide ly distributed in the Riddl e quadrangl e. 

ccording to Dill ~/ they include a lte r ed gabbro , diorite , and diaba s e and finergrained a t er ed b(;.. a l tic r ocks , a ll of which how evidenCB of crushing and ve ining . 

The gr een t one s in the · edia te icinity of the Silver Peak mi ne s a re ~ 

"'ail 'n ly fine- gr a ined, a lthough son e c .. r e p or:phyri tic . All contain abundant ep ie, f i ne- r a ined quartz·, chlorite , zoi i t e , au s uri t e , a nd other a lter tion 

pro · etc . Some e t a i n a sugg stion of i gne ou. t exture , bu t othe r are en t irely 

ged to r ock co osed ec enti a lly of ep i dote and q .artz . 0 e wa s not observed 

ree st one i n the Silver PeaK di st rict, a lthough el sewhere i n southwe t ern 

e on or e is en r ally as oc i a t d ith t hat rock . 

0 e deposits 

Geogr aphic di vtribu tion 

_hr ee i ne s ha e been · or ked i n t he icinity of Sil er ea . T o of the e , 

elongi to the Sil er e~~ Copper Co . and t he Ump qua Con olida t ed 1n1ng ., l i e 

o h of Si l ve r Peak . he i nclude ti ns of the ~arn e or e body and fo r cone a e descri bed t ge t her. The t h ird, the Golde Ga t e ine , lie abo t half 

o e north . 

a e on 

e.bo t 

3. I R. 6 

~ e nor th 

D o i t v OU h of Silver Peak 

Hi to y ~ d de e l opment 

of t e il er P e 

lope ~outh nd 

nd the 

':'ho. ::t~o , • E . 

purcha ed p - t 

:3/ 

- Dill er , J •• , o • ci • (Riddl fol i o ), pp J 4-5. 

0 . 

·, 4 I 

!::2.1 Th br oken l i ne '" hown on p l t 4 a s dividing the two pro ertie s was pointed out 

' dergr ound a c the bo da y l i.ne . 

21 Hi ntori ca l a fur i hed by J . E. R eves. 

16 
EXPLANATION 

Mas~i

~ ve sulphide ore 

fault 

~ 

Shaft 

Ill Ra is e 

s 

Winze 

::::o:it 

l'~ 

.. .s' 

i 

0) 

~ 1.. 

§ 

. o-

") 

~ 

~ ::;, 

o0 

i 

CROSSCUT S IL V£1? PEAK COPPER COMP_.q 

100 o 100 Feet 

1\1)--

;;;-<::-'<> 

~ 

~0~"? 

,#.rllJ ~q, ~ 

.,__fb (fb 

.... 'b .::l Q' {• 

i>.._<.~ 

~<:-'rio ., ,o -<:-'b 'b 

<. • ..S ~$' o.r:l 

~ 

Pc::;... 

...., C'o_, 

.so <:'-<::> 

.... o 

0' -Q 

..$'0 0 

llJ~ -o ....,.>-~<) ~b 

-1,.._...--v 

-".-z_.G' 

~q, 

4_0 

C'o 

~..-.::. 

....,-1.-..L 

.·(-:.~~::= ,tl:po ro

" us leached 

'v\-..J. f?. gossan 

% 

a.:)£. Mas.sive ~ul phides, l~rge y :t)t pyr1te w1th some ox1dat10n 

:.::: 

M.IIP OF' THF. UNOERC!lOUND WOill\ 11\t:::; OF' THP. ILVER PEAK 

MINING (.'0. ANI! Ll~ ll'II UA COI'SOLIDATEO MJ:-:JN(; CO. 

N 

I 

C lltt.;lll..I\.R. :! 

~ 

c: 

C7 

Shaft said to be 30 feet deep ~ 

~ Sulphides(pyrite) on dump 1)~ -8 

0/:} ;;*(() ..... () 

~'c..o 

0() <:- (. 0 

~~!! 

c: .!:l :c ~:S ~ 

2~ i~ l...c e>lll 

.8.§ ~~ 

afo 0 .>, .._._ ~- .... 1.. 

-<:-~ ... l. ' *-' 10 

(. ~ ..$'~ 

~·o~:l 

$. .. ~ 3 QJ 

0 i: ~c: 

~6: .c: 

(..) 

0 , :t: 0l. 

~~~~ 

·-.0 

~'5 "3co 

"fR 0c: 

~~ 

t>..C 

CJ·t:' ~~ 

l 'l...\1'1:: I 
73165 

inC~ been developed.. Litt1e work was done until 1920, when the Oregon. Expldira-

~ion co. located mineral claims over part of the timber claim. From 1922 to 1929 

the property was in litigation, but duri!lg this period and in the following year 

3

,256 tons of ore was shipped from ~Yorkings now owned by the Silver Peak Copper 

0 .W In 1929 the Oregon Exploration Co. was reorganiz ed as the Umpqua Consoli-

~ted Mining Co . This company shipped one car of ore (38 tons) in 1930. Both 

ines were idle at the time the writer visited them in September 1930 . The gro ss 

value of the ore shipped , not including zinc. is estimated at $73,000 . 

The ore bodies have been explored on three principal levels. The lowest , the 

n l evel of the Umpqua Consolidated Mining Co ., is a cross-cut adit 600 fe et 

~ with t o drifts aggregating about 600 feet . The main l evel of the Silver 

Pe~ Copper Co. , 55 feet higher than the working mentioned and conne cted to it by 

a raise, .is another cross~t adit about 480 feet long with 550 feet of drifts. The 

~h ird l evel , known as No. 1, 195 feet above the Umpqua level, is an adi t 170 feet 

ong driven near . the dividing line of the properties. There are in addition several 

~llow workings including a 30-foot shaft at a point 75 f ee t higher than l evel 1 

~d 270 feet above the main level of the Umpqua Consolidated Mining Co. Comfortable 

~amps have been built on both properties, and at the Silver Peak Copper Co . ' s mine 

a ·o, 10 Inger soll-Rand compressor and a Fa irbanks-Morse 120-horsepower engine , both 

~, we r e installed in 1930. 

Ore bodies 

The ore minerals occur as rna sive tabula r bodies and disseminated in highly 

:'oliated cchi t . The two principal workine;s expose a zone 'of mineralized chict 

c re than 100 feet wide . .Across most of this zone sulphide r.lineral s are r ather 

~~ ely distributed, but in at least t wo places bodies of nearly solid sulphide 

.re occur. One of these . in· the main crosscut of the Silver Peak Copper Co . , the 

northwest band, 11 in about 15 fe et wide and another, the 11 southeast band, 11 is over 

2· feet wide. (See pl. 41) Both pinch out ~o the northeast, one within a distanc8 

'200 feet and the other within 60 feet . Two sulphide bodies a r e exposed also on 

~ e main level of the Umpqua Consolidated mine , but ther e the northwest body is only 

~·out 10 inches wide, whereas the south ast body is about 10 feet ide . Normall, · 

~he massive ore grade s into schist with d.isseminated sulphides, but in some places, 

:specially where the massive ore pinches, one or both walls are slickensided fault 

mrfaces commonly lined with several inches of gouge. 

The rna sive ulphide ore is distinctly banded, probably in part because the 

.re mineral have replaced schistose rocks and in part because the minerals were 

: troduced along par all el fractures in the rock. The sulphides include pyrite, 

~hale rit , chalcopyrite, bornite, galena, t ennant ite, chalcocit , a nd covellite, 

~ed in the r elative order of the ir bun~~ce. The l~st four mentioned occur in 

relatively small amounts. In addition the occurrence of na tive copper is reported 

' y r . Reeves . The gangue mine r als are principally quartz, barite , and sericite . 

~idote was seen in one thin section of the ore. 

~/Production data furnished by Victor C. Heikes, of the U. S. Bureau of Mines . 

18 
?.3165 

At the surface oxidation is almost coraplete. Level 1, for example, follows a 

orous, ir on-st a ined, and greatly leached gossan in which no sulphides are visible. 

~shor t distance from the portal sulphides become visible a nd a r e abundant nea r the 

face . Sulphides werE; stru~k a.ls,; in the 30-foot shaft on the Umpqua. Consolidated 

property. Traces of oxidation extend as deep as the lower l evels, as shown by thin 

fibns of oxide minerals along fractures. 

HAULAU LIVIL 

' I I 1 1 9 •p f"t: T 

Fi~e 2.-Cross section through stope along line A-A, plate 4, Umpqua Consolida t ed 

l evel . 

l. . assive sulphide band; mostly pyrit · with a little visibl e bornite and 

other sulphides . 

2. as ive barite with sulphide stringers. 

3. .Aassive sulphide band.; P:YTit e with considerable bornite and chalcopyrite 

and l esser amounts of other sulphides. 

4. ass iv e sulphide band, largely pyrite . 

5. Sulphide bnnd i th ba rite string rs. 

6. as ive ulphide band, pyrite with considerable bornite ; some chalcopyrite , a nd small amo-..::.n ts of other sul phide s . 

7. ive .ulphide 1ith some small tring rs of barite ; this band i t self 

consi~ts of banded Gulphides. PJrite pr evails in orne bands , sphalerite 

in others . Bornit e a nd chalcopjG'ite and mall amounts of other sulphide s 

occur with them. 

Quartz was t he first gangue minera l to be dep osited. It i s r~Nhe e finegrained but t end.G to be coar ser i n the fractur s al ong which it wa s introduced. 

Barite was introduced next, then frac turing occurred, and pyrite was deposited. 

After a . econd fracturing SJ>haleri t e , t ennant i te, cha lcopyr ite , bornite , gal ena, 

~d chalcocite we r e deposited a s an overlapp ing series und probably in the order 

~( ed, a lthough the r elation of galena and ch lcocit e was not we ll established . Seefi g . 3.) 

19 
73165 

The mineral composition differs in the different ore bodies and within the 

layers of a single ore body, s. shom1, ~or example, by. the northwe st and southeast 

re bodie s in the Umpqua nsol~da ted m~ne . The sulph~des of the northwest ore 

~odY ar e associated with a bundant quartz but very little barite, whereas the s outheast ore body contains much barite and smaller amou..Ylts of quartz . The southeast 

bodY in the stopes above the level consis·ts of nearly s olid s1..U.phides with s ome 

layers of barite. The barite is lenticular in outline, and any one l aye r does not 

uersist very f a r. The sulphides e.re distinctly banded. One stope shows seven 

distinct bands with parallel structure . (fig. 2). The cornposi tion of the northwe t 

ore body r e senbles that of l a yers 3 and 6 of the southeast ore body a"' shown in the 

illustra tion. The ore exp osed on the Silve r Peak Copp e r l ev e l more nearly r e -

sembles the ere of the southeast ore body of the Umpqua Consolida ted l eve l. Howe er , in some places -- for exampl e , near the to_ of the connecting r a ise -- the 

copper sulphides a r c l ess abundant and the proportion of barite i s gr eat e r t han 

omal . At the turn in the drift, 30 f ee t northwest of the raise , the rocks a r e 

argely r ep l a c ed by very fine gr~ined silica t hat has irregula r red j asperlike 

reaks . 

Four ca refully cut samples taken at selected pla ces serve to show the r elative 

proportions of the metals to one another but do not necessarily illustra te the 

a erage metal content of the ore, which may be more closely determined from the 

production figures that fol l ow. AMlyse s of the sampl e s made in the chemical 

laboratory of the United States Ge ological Survey are given be low: 

Sample 

no . 

8 ..•..•. 

....... 

10 •.•...• 

11 ' ...... 

~~al ses of ores from the Silver Peak district, Oreg . 

~E . T. Erickson, analyst] 

Silver ounces Gold Copper (pe rcent Zinc (p e rcent) 

e r ton) 

0 . 59 4. 05 5.5 

. 30 . 90 . 9 

4.58 5.13 7.5 

. 46 . 93 . 6 

8. Silver P eak Copp e r tunnel, northwe st ore body. ~~ le t aken i n stop e 33 

feet above tunne l l ev el a cro ss ~ fe e t of massive sulphide ore . 

0 Umpqua Consolidated tunne l, main cros cut immediately northwest of nassive 

Glliphi de band . Sample taken a cros s g fee t of s ch ist with d issemina t e d sulphi des. 

10 . Umpqua Consol ida ted tunnel . Samp le t aken a cross 7 feet of massive sulphide ore in stop e along line A-A! p l a t e 4. 

11. ilver P eak Copper tunnel , 30 fee t northv1est of t op of connecting r a ise . 

ampl taken a cross 6 feet of intensely silicified !'ock containing s ome vi ible 

sruphidcs . 

The r esult show that copp r a nd zinc increa e c.nd de crease toge the r, but 

i dicate no simila r r e lations b e tween· those me t a ls and gold and ilve r or be twe en 

he gold and ilver themse lves. 

The following t able i s based on the p roduction figures furnished by V. C. 

He ikes , of the United States Bureau of ltine s : 

20 
73165 

Ave rage metal cont ent of ore from Silver Peak and/~nsolidated mine 

Year Ore p r oduced Gold (ounc e~ 'Silve r ( ounces Copper (pe rcent) 

(tons) per ton) p e r ton) 

-

Silver Peak 

1926 . . . 383 0 .12 7.3 6 .0 

1928 . . 0 37 . 044 2.7 6 . 7 

1929 . 1666 . 07 3 . 6 5 . 6 

1930 . . . 264 . 057 3.0 4 .4 

Ump~ua Consolidated 

l :J 30 . . . 38 .24 2 . 2 3 . 9 

Ori in of the ore 

he mine r a logy of the orcs described above is evidence of the ir hypogene 

(deep- seated ) orig in -- that i s , the mine r a l a~ emblage as shown by the ca r e ful 

ob e vat ions of many geo log ists belongs to Li ndgren ' s mesotherna.l t ype , d eposited 

at mode r a te depths by hot so lutions . The ~ource of t he solutions i s not evi dent 

from the ge ology i n the immedi a t e vicinity of t h e depo sit, but quartz diorit e and 

related rocks , hich a r , beli ev ed to b e the s urce s of man-r ore dep osits i n outhwe., cr ?l Or e on , a r e exposed a f e . mil s distant a nd ar e p roba bly not far b el ow 

t e sur_ace a t Silv e r Pc::ak . 

he ore - b earing oluti ons, hateve r tt-e ir s ource , d eposited gangue and ul -

p .ide mineral as they moved throueh t he schi sto se rocks . m}:e s o lutions appare t l y 

ro e alonu p lanes of .., chisto si ty and r ep l a ced t he adjo i n in nate rial . Ce r tain beds 

i the chi t e r e appar ently e ithe r more sus c ep tibl e to r epl a c ement or e r e . ore 

rea il pene trated by t he solut i on tha~ others , becau"' e solid s l phide occur inter -

be cd r;rith sc i. t in TJh ich ulphides ~-> a r se ly d i s tri •t ed . · he comp ositi on of 

t .e o e- ben. i ng s olut ions p roba bly chan.aed ':lur ing the ,Je riod o.f dep osi t i on , be ca e 

. .ineraL of diffe r e t composi t io hc'l.ve b ee n dE.:p o i t 8d in a n o e r lapp i n ucce io 

o e ents occu rred within the rock during the in al iz at on , onc e a t e r the 

gangue ineral ·vsr e deposi t ed and , ga i n (_ ,ft r the deposi t i on of the pyrite . The 

-"· er sulph i des we r e d8p o i t ed a a continuous sori s . Aft e r tht: dep osition of the 

~phid e0 , str a i ns ithin tho ro ks we r e r e l i e ed along fa lt , some of h i ch ha e 

d' pl aced the or e . ' or e eccntly the cl n i d s near t be u f ce ha ve be n ox idi zed , 

a d much of tr e metal conte n t of tl e out c. o:p s ha ~ been r er oved by l e. h i ng . Ero ion 

ha ep t pace fairly e ll ·fi th the oxidation , fo r t no p l ce in the vicini y a r e 

xid.e .. i e r a l kno m in a bun n.nc e vory fa .. ·~ n a th the f a ce . 

Econo:-a ic pe .t s 

he o e bodic a t the Silvnr Peo._l( opp =- r cvnd )q · o oli dat d mine have 

t een uufficicntl dC' e l y• d .,o e it t tonna,-s .. e t ·ma t e , no r ha t he 

ground in the . edi a te ici it be c•uf:!.'i iently exp lor ed to in ica te he p rohili ty of discove r e d or e bodies nearb , b t e· o h , ork has be en do e to d emontrat tha f a irl l a r ge bodi of o~d-~ de nassi e s l phi e ore a r e p r e nt . 

l o "'a.;tpl i n hov t hat the r . i s a po ibility , h en me; t al p rice r covv r, of 

mining an milli lo or - r ade di cmi na t · d o e a lon t~ the hi r- ado a t .rial . 
A. Born ite {bo) replacing pyrite (py). Reflected l ight, 

En larged 100 diameters. 

B. Sulphide ore, illustrating intimete relations of 

minerals . ba, Barite· sp, sphalerite; g, galona; py , 

pyrite; b, bornite; stippled areas, chalcopyri t e . 

Enlarged 100 diameters. 

Figure 3. - Photomicrographs of ores, Silver Peak mine . 

22 
73165 

Only a very small percentage of the sulphides found on the lowe r levels are 

s pergene (de s c ended from above) , a nd therefore it follows that there is not 

ch likelihood of a n:r ma teria l ~a ~e i n the meta l con t ent of the ore for~ s ome 

lit.tle di ct a nc e be low t he p r es n t d_ec;pe st l ev e l . Ho rvc v e r, owi ng to the fact t h t 

the outcrop has been 2.mos t en t ire l y ox i c1 ize d a nd rruc} of t he me t a l l ic co t ent 

removed , more or l ess sulphide enr ichment is to b e e:;:pe cte d :immedia t e l y belov 

the zone of oxidat i on . 

The f a cts a va ilable p e r mit s o e co usions as to the p robabl e v e rtica l and 

orizont a l ext e1 t of t he ore . Folia t ed s ch ists im l~r to those con t a i n i ng t he 

ore a!'e exp o sed a t t..1 , surfa c e f or sone C. i t a nc e north a nd o 1th of the lmo n ore 

i es . In pla c es they a r e mi ns r a l iz cd-- for cxw p l e , a t t he Golde n Gat e mi ne , 

'he nor th , des cri d b e l o . Some mi ne r a liza tion ·as a l so note d i n a s ch i"t 

i l ilar app ear ance about hal f a mile t o t h 2 s outhwest. Unde r ground the or e 

be8n follo1e d u l ong the trike fo r a t o t a l dist a nc e of ove r 450 f ee t , and in 

a least t o p l a ces it continu es be;yond the p r e ent TO r .. -i ngs . Bo th bod i e of 

~o_i d sulphide or e we r e sheare d off i n t he n or theast dr ·ft c of the Silve r Peak 

apper o . 1 s ma i n l evel but c ontinue i n to t h e ·ral l s t o the outhwest of t he 

re::.:ent YT orki ngs . The sout heast ore bod, on t_ e Umpqua Consolidat ed le e l ap . ear a 

~o urn i1 to tho sout 1e ast rval l of the drift abo·u.t 50 fe e t f roo t he fac e . It 

a_pear a l o to hav unde r gone shearing , and. f urthe r or k may p r ove that i t i s 

di _le1ced . At the sout!1 end of the sN. e drift the or e e~ppoa s t o end again t a n 

est- rest , so t"h a r d - i p i ng f au lt . Sul phid.e ore i n t e r l ye r ed 1' th barit ~ is ex-

":)osed on one side of thi s rift about 20 f ee t fro t h e fuc e , and· it seems l i kely 

--.1at t· e ore boC.y may cont inue sout h!l st.var d fr o!tl t h i s po i nt . Tlus the j_ denc e 

·· ound doe s no t suggest that the ho rizontal l imits of t e ore b odi es ha e 

· een r eac ed . Even w, e r e the ore is hec.r e d. off by faul t i ng t e r e i s no 1mo, 1 

:eason hy the segmer1ts may not b o r e cc:>vered . Outcr ops of partly oxidiz ed ~ 1-

. ide ore occur 140 and 270 f ee t a ove tLe or e b od i es found on the t o ma i n 

:e el . o rai. e have b een dr ive n t 1rrough to the su f a ce to p r ospect t he g r ound 

·)e \ een hese o tcrop s , a l t hough a t one plac or e 1-'...as b '"'en sto ed abo~ tho 

: ·1 e Peak Copp e r Co .'s l eve l for a re rti cal d i t c-nce of about 90 ro~t . I t ee 

eason~ bl , however , to exp e ct the ore to continu e to t h e urface , though ot 

r.ecessaril y a '"" one cont i nuous body , be ce<,"G..se of the po ss i b i li ty of fa l t di spla e -

me t . I t i gen erall r r cognized that tl e r e i s u ually a r e l a tion h i p bet een the 

:orizontal exten t of a n or e body and its d.o vnward ext en sion , and as t h e o_ e bod i e 

· der discu si on a r e eArp O e d ~ the low r l eve l s ove r a hor izm t a l d i t ance of 450 

fee i thout h ving ended, they ca n r ea onab l y b e expe cte d to ex t nd f or some 

uis ance b lo he p r eser t 10 r k in u . 

Deposits no r th of Silve r Peak 

o t of the ini on the no r th i e of Si lve r Peak has been done · y ~ A. 

adfield on the Golden Ga t e property . He l ocated -.-ven cl i . s i n l 1 , d a l -

though les e shave ince wor)<:ed the property , he ot i ll r e t i n t he o e r shi p . 

. ccording to . B c:;.dfie ldl7 I t\10 ca r s of or hc't.VO be en shipp ed . One car conaining 3 tonu gav t;,ross ~ Le lte r r e turn of li' l , OOO , o tly i n g old, a nd a nother 

car shipped by l e ssec v is r ep ort d to 1 a e r e tu ned ;:;> l . 7o a t on • 

.1/ 

Personal communi cat ion . 

23 
73165 

In a ll, about 600 fee t of unde r g round deve lopment work has be en done . 

Mos t of the work has been c onc entrated on the cL ims near the roa d in t h e 

icinity of the Bradfie ld cab i n ; the r ema inde r on clalins nbout half a mile to 

'he east . 

mhe p roduct ion has cor e chie fl y from a n open cut and s ome shallo worki ngs 

close to the Silver Butte road . The or e: occurring h e r e i s a dar k g r ayi h - g r een 

chlorite schist strik i ng _ . 30°- 60° E. a nd dipp i ng 50°- 70° SE . A l aye r i n the 

schist cont a i ns pyrite cube s a nd sone st r i nge r s of chalcop yri { e , and a ccording 

to r . Bradfield fr ee g ol d can b e panne d fr om s ome of the rock . The :p· rite cubes 

range in ize from t hose t ba.t a r e b a r e ly vis ibl e to some with f ::1 ces ove r half a 

i..ch ac ro ss. The cu-be s c t a cross the schistosity of the nc lo sing rock , thus 

indicat i ng t ha t ths y wo r e forme d. l a t e r . 

Tvo tunn els hav e b e en driv ~ on a mine r a lize d b e d in foliat e d s chist at a 

oint eve r a l hundred f e et east of the vwrki ngs ,just des c ribed . The t 10 t unne l s , 

~ ich differ i n a ltitude by 90 fee t, have explore d t he mi ne r a lize d bed for a 

otal di t a nce of a bou 170 feet . The ~c1ist i s L~ilar t o that contai ning the 

-i ., e . i nat ed ore a t the Sil ve r Peak Copper an Ur.1pqua Cons ol i dat e d _ ine s a nd 

urobabl a s . :ne r a l iz e d unde r i Tn i l a r cond. i t io!ls and a t the arne t i. e . I n c on-

-trast , ho 1ev e r, ve ry litt l e quartz or barit e was n ote d in t he dep osit at the 

oldel Ga t e mi ne . 

~ 

Almeda 1 i ne, .Jc-.5· /fc, ... < Lo . 

.uoca tion and a cces_2.. - The Al eda i ne i s on the north ba ru<: of the Rogue 

River in the SE-i- s e c . 13, ... . 34 S ., 8 • ~ .. illame tte me ri i an , 26 mi les below 

rant Pa ss a r cl 4 miles from Ga lice . 1. e rlin , on the ma i n li e of the Southe r n 

_acific Railroa d 19 mi les to the south:re st , i,... t e nearest a cces il.:lle h i pp i ng 

po i t . A ~oad to con ect the ine with Le l and , also on the ~outhe n Pac i fic 

fu ilroad but on ly 10 miles d i s t ant , V1 as sta ted but neve r co p l e ted . Hi h 

~a er ca rrie d a ay t he bri dge trc t once connect ed the __ i r1e i th the e r lin r a d, 

Md a t pra s ent to r e · ch the mi ne it i s n e c essar y to cro s s t h e Ro ~e Rive r on 

an ae ria l tram or by boa . 

History a nd p rodu ction . - The Al eda .. ine ha ben kn ~ fo r many yea r s 

ecause of the g r eat extent of the mine r a li zc:tt ion and b e cause OLe f a irly l arge 

.la e s ithin the mine r l i z ed zone contai ~ e nough gold and othe r .neta lf to atnotice . Con~equ 1 t l , a smal l !e lte r a built i n l 08 , but no p r oe or t ed until 1911 . Fro, 1911 to l 0 16 , 16 , ol9 ton of o c th3. t 

yielded 1 , 53 . 87 ounc e of gold , 4 8 , 387 ounce of il e , a d 800 pounds 

~a::; p r od c ed . A t o t a l of 7 , 19 7 ounds of lead va als o r epo ted as 

r om 5 189 t ons of ore r l . 13 1015 , n~ 1 16 . -,o lead ~a r e -

1 11 , 191 2 , or 1914 . 7he g r va lue of t h e or e roduc d, on the basis 

t hese f i e~ , is, in r ound numb e r s , $108 , 000 . 

-The Alm da mine ·~ one of the mot ·xtensive ly deve loped 

ni ne..., i n ou t hv .., t e r n 0 egm . A rr inor a li zed zone ha~ b een pro pect ed fo r or e 

1 , 000 f eet alon& it strile a nd fo r bout 900 f ee t ve r tica lly. Five adit 

e been d ivc n , a nd a haft 1ith l ve l a t i n t e rvals of 100 f e e t 1as unk to 

a depth of a bout 450 f ee t b e lo the Ro ::> e Rive (pl . 5). h e shaft i s no longe r 

acce i bl e , but mo t of the ' or k i n abov8 the rive r a r e open . 

24 
SOUT 

l 

I 

~ (I 

\l 

c 

~ 

I 

/; 

N~ / l AOff / 

-:· / 

~~· 

\\ 

.':" 

.. // 

<Arr; :.:·.·:j' 

.··:.··· 

r, ,. -:_ .... :\ \ 

CIRCULAR 2 PLATE 5 

NORTH 

~~=============r~ .. ~-=~.r;~;~,=== ~-~;~~,;,~~~b;~=C R IVER I 

f) 

,, 

,, 

,, 

II 

1/ 

/1 

1/ 

levi'!/ ___ _ 

....... :-:::::::.:·:·: .. :· ..... ::::::::::::::~::::::::) 

PLAN 

~~ IOOfcc 

SECTION 

_:.$ 

---------- _\ _ _.."'....0--~ .~~-;--" 0''""/ 

// 

/:; :' ~~;;~~;, L-~~·' 

PLAN OF A PART OF THE UNDERGROUND WORKINGS AND LONG.ITUDINAL PROJECTION ON 

A VERTICAL NORTH-SOUTH PLANE THROUGH THE WORKINGS OF THE ALMEDA MI NE 
General geology. - The Almeda mine is near the contact of the Oalice fo~ 

tion ~d a thick series. of g~eensto~e rocks. Nea: ~he co~ tact both form~tion~ wve been intruded by s111-11ke bod1es of porphyr1 tJ.c dac1 te. At least six of 

these sill-like bodies are found in the Galice beds within a distance of 800 fee't.i 

t the east of tunnel 1, and several of them are exposed in the greenstone rocks 

~st of the Alme~ mine. All of the formations strike approximately north and 

are vertical or d1p at very steep angles to the east or west. 

The Galice formation in the vicinity of the mine is comp osed principally of 

Mrk-colored argillite and slat e which on the basis of fossils collected about 

lOO feet east of the mine have been assigned by Diller to the Jurassic period . 

he rocks a r e composed largely of subangular quartz and feldspar gr ains and 

sericite. The original minerals have clearly undergone considerable recrystallization, and near the ore bodies they are largely replaced by calcite and 

rtz and contain much disseminated pyrite. 

Tpe greenstones consist of gr eatly altered even-grained and fragmental 

igneous rocks containing much secondary chlorite and epidote. 

The porphyritic dacite, where fr esh , i s a dark-colored rock with abundant 

:arge phenocrysts of dark-green hornblende, less abundant and smaller crystals 

of plagioclase, and a few scattered quartz phenocrysts hich a r e noticeably 

:-ounded . The appearance of the porphyritic dacite changes gradually, depending 

~on the amount of mineralization, from the fresher rock just described to a 

;~ck in which the feldspars have been altered almost entirely to sericite , from 

·Mt to a rock composed almost entirely of silica and fine-grained pyrite but 

:-etaining shadow outlines of the original texture, and finally to the sulphide 

e, a rock composed essentially of fine-grained quartz, barite, and massive 

sulphides ~n varying proportions. The microscope shows that the feldspar of 

even the fr esher-appearing porphyritic dacite is mostly alter ed to a mass of 

sa s~ ite, ~lcite, zoisite , and epido t e . Unaltered areas remaining here and 

here have the composition of andesine. In the fresher-appearing rocks the hornende is o~ly slightly altered, but near areas of mineralization it has been 

ruwged to masses of chlorite, epidote, and zoisite, and finally in the silicif'ed rock it has been almost entirely rep laced by fine-grained quartz . The 

0 roundmass of the fre~her rock io composed of very finelygranular feldspar and 

q~rtz, sa~ssuritic material, and chlorite. 

Composition of the porphyritic dacite footwall from the Almeda mine .

18/ 

Analysis 

203 .. .............. . 

?e203 .••••.•....•...•• 

?e .......•...•...•••. 

.., gO •..•••••••••••••••• 

:ao ... ............... . . a2o .. .... ....•....... 

7. 

...... 2 ..........••....... 

.20+ .••••.•• ~ •.•••.•.• 

55. 92 

.75 

19 . 66 

1 . 94 

4.76 

5. 27 

5.77 

3.26 

.38 

2 . 90 

Hz "7 ••••••• , • • • • • • • • • • • o6 

100 .67 

[s. W. French, analyst] 

Approximate mineral composition 

Quartz .............• 15.6 

Orthoclase ••..•..... 2.3 

Plagioclase ...••.... 56.4 

Chlorite) 

Epidote ) ... · ·· · .... 22 '

1 

~agnetite •.........• 2.8 

Ilmenite. . . • . . . . . . . • 1.4 

100 .6 

8/ .. - 1nchell, N.H., Petrology and mine r al r e sources of J ackson and Josephine Counties, 

reg .· Mineral Renources of Oregon, vol. l, no. 5, p. 209, Oregon Bur. Mines and 

Geology • .A.ugu.st 1914. 26 
73165 

Although cla3sified by Diller as a quartz porphyr y or alaskite , the porp fi i t ic rock described a bove is both mineralog ically and chemical+y a p ori tic dacit e . 

Or e bodi ec 

The or e bodies a t the Almeda mine occur in a wi de zone of i ntence i l icif ica ion, known as the Big Yanl:: lode (fig . 4) , that follows close to the contact 

of porphyrit ic dacite a nd a r gillite (sl ate) of the Galice formation . According 

to Dillerl9 / ho ade a broad study of the gene r a l r egion , 11 the contact between 

· 8 sl a t es and the i gne ous r ock , with h ich the Bi g Yank lode i s a ss ociated , may 

~ traced fo r over 20 miles i n a dire ction about N. 30° E . from Briggs Creek 

alley to Cow Creek at Reub en Spur. Although the gene r a l course i s a i n t a i ned 

wi h conside r able r egul arity, there a r e many smal l vari ati ons, and the cont a t 

·ps t o the s ou th ast i n the same d ire ction as the sl ates. The plane of the conact i gene r ally a fault p lane and i s fo r the most part follo ed by the lode . 

The contact i s appar ent l y most irregul a r and the quartz p orphyry [porphyritic 

dacite] .ost cut by shearing plane in the vicinity of the ore bodi es . 11 

!·~e 4. - Almeda mi ne and Big Yank lode , looking north . l , Sme lter; 2 , Bi g 

Yan .. 'k: l ode ; 3 , mouth of tunne l; 4 , gr avity p l ane . 

The Bi g Yank lode , fo r the most part, consists of i1te sely ilici fied rock 

~ ' th variable a.11ount .., of p yrite , b t in p l aces .asse s of the si lic i f i ed ro k l'k'lve 

· ee. partl or holly replaced by barite and s lphide , wh ich const i tute he 

r'c er or e shoots . The mine ralized zone on tituting the Bi Yank lode varie i n 

id h from pla c to place but at the All e ~ . ine i about 200 fee t ide . T 10 

~yPc., of ore bave been p r ev iously do cribcd; 11 )iliceous 6 old- i l ve rare 11 and 

~ 0 • D1ller , J. , . op . c1t . (Bull . 546) , pp . 74- 75. 

27 
73i65 

' 20/ "coppe r ore with barite .''- The "siliceous go ld~ilv r ore" is the intense ly 

ilicified :rtock with vari able amounts of pyrite described above ; the 11 copper ore 

1 ith barite rt comp rises tho se portions of the Big Yank l ode that have been partly 

or wholly r ep laced by barit e and sulphides. 

The "siliceous gold-silver ore n consists large ly of intensely sili cified 

uo~hyritic dac ite . The rock is comp osed almost entirely of quartz , but pseudomorphic out l i nes of the orig i nal t exture a r e shown i n thin section (fig . 5) . 

Al though the qlk~rtz in general in f ine- gr a ined, it t ends to be slightly coa r er 

along veinle t . The r e a r e t wo and p ossibly three gene r ations of quartz . One and 

o~s ibly two pr eceded the sulphides , and one clea r ly cuts t he sulphides . In 

-eneral , the older quartz is very fine gr a ined. I t is traver sed by eome ve i nle ts 

0 oa ~e r quartz that is believed to be of t he same age , but becau3e this coa r e 

quartz crystall ized in the fractures thr ough which it was introduced , it t ended 

· form larger in~ than in the r eplaced wall rock. :Sari t e i s paringly p r e ent 

L the 11 ci l ic eou ... gold- silver or e . 11 It wa i ntroduced after the older quartz but 

preceded the sulphides . 

According to P . H. Holdsworth,?Jz../ engi neer for the Almeda mine in 1911 , the 

a erage analysi'"' of the 11 siliceous- go ld-silver ore " i s as follows: 

Aver age analy is of siliceous gold- silver ore of ALmeda mine 

~i02 ...................•... ~p ercent .• 62 . 9 

F~ • . . • . • • • . • . • • • • . • . • • . • • • do 11 .5 

CaO . . . . . . . . . . . . . . . . . . . . . . . . do 2 . 1 

BaO . . . . . . . . . . . . . . . . . . . . . . . . do ·a . 1 

Al203 . . . . . . . . . . . . . . . . . . . . . . . . do 5 . 6 

S . . . . . . • . . . . . . . . . . . . . . . . . do 8 . 3 

Cu . . . . • . . . . . . . . . . . . . . . . . . • do • 3 

Au ....... ounces pe r to 1 . . • • . • . . • • • • 0 . 14 

Ag . . . . . . . do . . . . . . . . . . . . 6 . 40 

he gold and silver content ho~ above i s higher than i n the i liceou 

,ate ial collected by Diller i n the west cro sscut of the 50 - foot level . He 

rep ts tho.t/a ay3 of his spe cimens contain very l i ttle gold and only a t r a ce 

' lve . 22 Tho writer cut t hree channe l samples a cro ss the body of the 11 iliceous old- silver ore " which a r e believed to be f airly r ep r e ent ative of 

· e places sampl ed but , like Dille r ' s pe cir.en , i ndi cat e o ly t hat t ' in type 

o e is low- gr ade aterial . The parti a l analyses of these samp l e made in the 

c emical labo r atory of the U ited Sta te s Geological Survey g i ven on page 30 a r e 

her efor e not pr e ent ed as r ep r esentati ve of the ave age me t a l cont e t for t h i 

~e of or e t~~oughout he mine • 

..Q/D. l 

1 1 e r , J • S . , op • cit . , p • 7 5 . 

ill) Idem , p . 77 . 

?2) Id m, p . 78 . 

28 
A. Silicified po rphyritic dacite, "siliceous 

gold- silver ore s . "Nicols cro ssed . 

Enl arged 41 diameters. 

B. Same as A, showing outlines of silicified 

phenocrysts. Sulphide ore black. Plai n 

transmitted light. Enla rged 48 di ameters. 

Figure 5. - Photomicrographs of ores Almeda mine. 

29 
73165 

partial analyses of 11 siliceous g old- silver ore 11 fr om the Almeda mine 

[ E . T. Erick son, analyst J ----.----------------- -·-------

17 18 13 --- -------------------------- oppe r ........ .. . . .... p e r c ent .. 

BaS04 • • . • • . . . . . . • • • • • do 

Si02 . . . • . . . . . . . . . . • • do 

old . . . . . . . . . . . . . . . • do 

ilver .......... ounce pe r ton .. 

Less than 0 . 01 

.4 

66.2 

Trace 

.17 

0 . 01 Less than 0 . 01 

Trac e 2 . 1 

88 .8 64.2 

Trace Tr ace 

.08 . 01 

17. From c r os. cut starting 200 fe e t fro1 portal of west adit of l ev e l 1 

and runni ng west . Sample r epr esents width of 10 feet; fror, face of eros cut to 

oint 10 f ee t east of f a ce . 

18. Same cro sscut ' s 17. Sample r ep resents width of 20 f ee t, b e tween po int 

34 and 54 f ee t east of face . 

13. West ero s cut 110 feet s outh of f a ce of Rive r l evel. Sample t aken 

ac o s 20 fe e t of ore . 

he riche r ore a t the Almeda mine , the "coppe r ore :.ri th barite , 11 oc curs as 

shoo ts close to the conta ct of porphyriti c da cite and argillite in the broad 

'licifi ed zone des cribed a bove . A long itudinal se ction of the mine workings 

a· o e the Rogue Rive r indicates that t wo mine r a liz e d zo nes have b een partly mined 

t hat most of the p rodu ction has come f rom one that i s . ore or l e ss par a lle l 

wi h and f rom 20 to 50 feet be 1,ow the surfa c e (pl . 5) . The othe r zone , which 

Ms not been dev elope d sufficiently to rmin e its p itch, is about 250 f ee t beow the urface . As shown by a ssays of saJnp l es collected by Dille r, and P. H. 

ol ~ 11orth , ore of good gr ade as found on the 300- foot l eve l (be lo the Rogue 

· er), but be cause the shaft is no longe r cc (~ . ible the r e l at ion of this ore to 

e hoots above i not known. The sho ot of b e tter-grade ore r ange in thickness 

L a few feet to 60 f ee t nd in length f ro . l ess t han 100 feet to over 200 feet . 

e gr eat est known idth i exp osed on l eve l 1 , wh e r e the ma i ore shoot i s 60 

feet thic1 and 220 f eet long . On the rive r l eve 1 the gr eat est vi. i ble thickne 

5 feet , but the ent ire thickness i s p robably not exposed . Accordin to 

iller the thickness of the p rinc i pal ore body on t he 300-foo t l eve l (below the 

~~e River ) is ab out 15 feet . 23/ He also r p ort the ab ne e of a con i de r a bl e 

body of ore a t the con t a ct by the shaft on the 500- foot l eve l but stat e that , 

a cordi ng to the pitch, the ore l oot found on the 300- foot l e e l should p roj e ct 

o a posi ion south of the shaft on the 500- foot l ev e l . 

The or e f ro the high e r- rade hoot.., i com_ o ed p rinc ipally of barite , 

.~r z, and sulphide . Th e b rit e as i n troduce d i to the inte. ely i licified 

prop yr i t;ic dac ite before the sulphides, ::~ d locally it has almo t comple t ely r ep aced the ua t z . The ulphides , i n turn , have r e laced the ba rite a e ll a 

t.e quartz . orne pecimen clearly sho ve i nl e t of sulphides c tting coa.r egained a rit e . Th sulphide"' i nclude p rite , chalcopyrit e , galena , sphalerite , 

c~lc ocit , and cove llite . Pyri te i s by f r the oct abundant . It occu_ through~ 

o the mine r al ize d zone but i s c onc entra t •d as rnas~ v bodi e in the r i che r ore 

oots . The pyrite i '"' cut and r ep laced by all t he othe r hypo ene ulphi dc a d 

by co ellite , which i s cl a rly vupe r g ne . In the b e tte r-g r a de ore exposed in t he 

3

/D'l - 1 ler, J . S. , op . cit. , p . 78 . 

30 
73165 

ac essible stap e s tiny ve inlets containi ng covell i te a.r e plainly visibl e cu ting 

the other sulphi des a nd the gangue mine r als . 

2A I According toP. H. Hold worth ~the " copper ore v1ith barite " a cro s s vidth 

f 6 to 20 f ee t wa s a nalyz e d a s follows : 

Ana lyses of copper ore from Almeda mine 

Si02 ............... 8 . 8 to 5 . 1 

Fe S2· · ..... . . . .. . . 27. 0 to 4 8 .1 

CaO .......... . .... Trac e to 0 . 8 

BaS04 . . . ....... . .. 4 7 . 8 to 2 8 . 2 

Al 203 .. .. .. ..... . . 8 . 0 to 10 . 9 

CuFeS2 .... . ....... 6 . 4 to 6.8 

A sa ys of coppe r ore f r om Alme da 1ine 

Cu . ......... . ...• p e rcent .• 1 . 5 to 4 . 5 

Au . . ........ ounce~ p e r ton 0 . 12 to 0 . 42 

Ag .. . . . .. . .. do 3 . 32 to 12 . 1 8 

A a rtia l analy is of a ampl e colle cte d by Dille r24/ on the 300- foot l eve l 

j ct or th of t h e cro s cut from the shaft va s made by Chc.tse Pa lmer , of the Un ited 

ate Geolog ical Surve y , and t h e amn l e as assa y e d f or g old a nd i1ve r by E. ~ 

~ l i ngame &. Co ., with t h e ro lla i ng ; e sults: 

Ana ly i of ore from Alme da mine 

Si02 .. ..... . . . .. . . . .. pe rc ent .. 0 . 31 

BaS04 ·· · ·· . .. .. .. . . .. d o .. 68 . 21 

Ca O... ... . .... .. ..... do 1 . 01 

Cu . ... . . . ............ do 6 . 02 

Au . .... . .. . ... ounc e s p e r ton . . 0 . 10 

Ag .. .. .... . ... do 7 . 78 

umer ous fault. cut both t ypes of or e . Stri {e f aults a r e mad ev i d nt i n 

places by gouge c:..l ong the cont a ct of t h e ore with the f oot val l a r illite nd by 

gouge earn a nd hattering in t he ore . Oth r f ault , part i e l rly t ho e 1 L ing about • 50 ° W. , hav e offse t the or e in a ny p l c e . (See l . 6 . ) 

Both ilice ou a d c opper - ba rit ore hav e 6 r ea tl l eached ou tcrop . The 

iliceous or e a t the urfa c e i a hite roc ... , r e e b ling quartzit . It c o t a i n 

~ s ot ha t a r e p or ous , o i ng to h e r e o a l of p r i t e . h e o t rop of th 

~Le r or e i . ro y d yello ~h a nd bro n by i on oxide and i comp osed 

largel ,, of po ou a g'' ego. e of a r i t e and qua t z . Ox i dat i on i not a bunda t, 

:o1e er , in e ithe r t ype of or e a t dep t h e x c edi g 50 f e t b e lo the urfac e . 

lllphid enri chm nt i a e e ident i n the s t ope e X3Jll i ned by the p r e e n e of 

i ny einle t .., of co e llit u t t i ng bo t h gangue and p rirrulr y ul h ide min r a l s . 

24/ 

- ill c r , J • • , op . c it . , p • 7 6 . 

31 
/'})e~ 

~it O f' 

Massive argi I lite 

impregna t ed w1th Fe 5 2 

P re c ip 1ta.te of coppe r s ul phate 

6fi'tL,.. 

CIRCIJLAR 2 

EXPLANATI ON 

'gr-<1.q 

Porphyr

~ 

~ itiC 

da.c1 te 

100 

m . 

' ' 

Ar gi llite w1th 50me quarlz 1le 

0 

MAP OF THE RfVER LEVEL. ALMEDA MINE 

1/·/1 Fau ll 

/ 

Vert ical 

faul t 

J ,{7o•j 

Str1ke a ndd1 

Soft. ~ou§i; or 

( S8mp e N . \ ;~~ ;: >· 

100 Feet 

PLATF. <; 
73165 

Orif, i n of the orG 

h ore a t the Alme da mi ne :b.Ds b e 'n f orr.1e d a l most ntir ly.;.;.~y- ·· he r eplac ement 

-"porphyY it:i c da cite close t o t he cont a ct v.ith a r g illite . Othe r b oq i e of o-

\ ri ic ,acite hav i n trude d a r g illite b e d s , bu t s o f a r as knm;rn the only contac t 

~t has been ext en _ ivs l y ne ~l iz d i s the one at the Al! e da . i ne lm o '1 as the 

iu Yank lod . Bo h. Dille r

25/ o.,nd vinche ll2Q7ba ve stated that the Bi g Yank lode ·_;_· .. · 

cJr-:-a1on a zone of f ault ing . Faulting a lone the contact prob bly c used the 

·8velop ent of the f r .:tc tures t r out;h .vhi ch the quartz has so p l a inly penet -. t e d the 

. k . R0)l a c e·:1e nt occurr e d ne[l.r t he co!lt a ct in both p orphyritic dacit J an 

a·gill i te , but i n the c.r g ill::. t c to a :auch l 0 sse r degre e . Aft e r int e11se s i licifia io and pos i b l y lyr i tizat iol, the brittle silicifie d roc_ s we r e agai fra ct· ed. arit e Lnd pro"bcJbly a d:l. i t ion=t. l qu2.rt z e r e introduced a long th fra ctur e 

a d ar ticularl' a lon the zone s of gr eat est s~tter ng . After the barite , u -

:; i es vere i ntr oduc e\.l- yyri te first , and the n the oth e r sulphides , ap a e 1tl a 

· o erlapp i ng se r i es . Li e the ba rite th sulphides t e nde d t.o fo llo the z .e 

: r .. ost i nten e ha ttering , ~1h ich , a s shorvn by t:t.:;; c onc entration of ba rit e a nd 

,·lphides , dev e lop ed clo e t o tl1e co .. tact of the p rop hyritic daQ:·· t e and r [;illite , 

v: u fo .ni ng the h i gh e r-g r ade ore shoots . Faulting made evident by OU6e , h.:l t -

te ri , and displacer ent of the ore continued a ft e.r the depo i t i on of t e ~nl hides . 

. , iJ,at ly ero i on br o 1ght the ore bod.i es clo se to tbe surf a c e , a nd. oxidatio 

a ttacked tho ulphides; .uch of the oxidiz e d mate ria l was r e o ed , 2nd o .e 

: ' he .. etals e r e ca rri e d dm n varcl to b e r e dep osited a uper e ne ulphide Ho · -

.ve , er o i on haco ne a rly ke t ... a ce ith oxidation , s o t ha t toda y t he r i t a 

t ·n zone of oxidiz e d in . 

or mine r al._ i s pur l y r,pe cu l 2.tiv . o st of the 

a 1. e a r.1 ine a r e char act e ri tico..lly hypo · e ne mine r a l s a nd h enc e , i 

lib .· of our p e e nt 1m0\ l edge , . ve r e ~;:; :i.. d rro.n one magma ic "'ource c lo . 

"'" ller t a t e that tl e porphy i tic dac i t 8 s a r e t ought to - e ge e t i cally; r 0l a t d to 

~: e ranodiori t e . a sc; s that a :!' G o .. xt0r i v i n ;;o O t h·.'7e., t e rn Oregon . 27/ ~ i th thi 

as · ._ t ion i t ay b e cxp ct od that th or e- b e r i ng olu tions r e ived f o. 

•:.a cue paren t ~n. a the ~orph;yritic da cite . 

Economic con ide ration 

TNo po r i biliti e . u t be si d i n dis cu s i .; thee ono .ic outlook fo 

· .. e , l eda ine--(1 ) th8 o ssibility of dev e loping an e n onnou tornevg f e lo 

g:a.e or . that vo ld be inr l ev en metal p ri e r e . e ; ( ) h ., ._, i ility o 

de·;elopi. g and o 1 ing . all e r hoo s of higher- r ade ore . 

i ho 1.t u tion 1 e e i a t the Almeda mi ne , an e nor ou e.:. o it of -. i l i i-

::e ro r co tai n i 0 variable runoun t s of pyri t e a ld orne il e r an g ol • hi 

::; t. e 

11 • i l iceou. go ld- "' i l v r or 11 entione d by Diller . en ondi t i onc .re 

:"a; ra lefor the _::ploitat ion of l arge lo v- ade depo it contai n i g i l e r , gold, 

a.'l ' copper , con i de at ion h ould be g i v n to th . i c r l i ze d zon t t . · 1m da 

~- . The ate i al , ex ludin the '-'hoot of b e t t =- r o , i ,rta inl r o -~ d , 

~t er e i a o ib ility that unde v r y fa r bl condition a l r ge of the 

& . 2B/ llle , J . S . , op . cit . , p . 74 . ~ . -- lnchell , A. . , op . cit . , • 208 . ?!_/ . 

lller , J . S . , op. cit . , p . 21 . 

33 
73165 

mi ht be worka.bl . Only ca r eful and com l t sampling ' ill det e rm i ne the 

na f , t 'bl'lit y o ucn a ve n ure . ea"l 

i ni ng has demon tra t cd the occurrenc e of - ood- siz ed bodi es of the richer 

t l east two have b en partly d eve loped. The l a r ge r a nd high e r - g r a d e body ha 

·· rt ly blocke d ou t fo r a p itch l ength of about 800 fe et . he smaller· body lie 

ore . 

been 

p~~ t 250 f e t nort:!.1 of t he l arger one a nd has been only slightly eve loped . I 

~s not _mo .vn by the wr i to r v1he the r the cont i :n.12.tions of Lese bodies ' e r e fm.md on 

· e l evels belo v th8 r i er . 

The out h or e body i s p r a ctica lly as lon on the r i ve r l eve l a on l eve l l , 

_00 fee t above , and i f it rus no t b een found on the 300- foot o:- shallo e r l eve ls 

' elo th a ltitude of the Rosue Riv ,r , the r eD.son i s p robably bE; cause ro spe ting 

~ ot been carried f a r enough to the so1t h . The north or e body has not be en 

e eloped suffi c i en tly to det r ine its itch . Ho eve r , it appar cntlv has not ue n 

d on th Rive r l ev e l . Di l l r ha sut;g st e d tha t the or0 f ound near the 1 ft 

0 he 300--f oo t l eve l might be the? ext en i on of thi ody . Eo veve r , if th _ i ch 

· aD roximat c: ly co::1st.::tnt , it should h~v c be t_; n i r t ·Tse ct ed by t h e :t:iv r l ev E:- 1 . 

r-for , it seems p r oba ble t ha t the no r th or bod· . a y 1 ve a st eepe r p ith than 

e o th ore body a nd t hat the ore body on t h 300- foot l uve l ay be a . e a r.J.t e 

. e. hi infer enc e i s i n o..cc ord 1i th the i nterpr t at ion of t:be ori 5 in of the ore -

•r.at is o say , the hi _her- g r ade shoot mi O'ht b ex ec ted alon the u.r g illi t e contact ' er cver i nt ense hat t erine formed pe r!!l ,abl op ening fo r the ore - b a ring 

s l ion to follo 

The hoots of riche r or · have b een found a t or v ry close to the cont._ .ct of 

argillite , and there i s a pos.,ibility t hJ.:Lt care f u l tudy mi gh t r e real undisco r ed 

'o s along the cont D.ct of the Bi g Ya11Jc l od . _he o tcrop s of the b e t te r oro 

C. if er em ~ icle r a ly fro t hose of t h ·"' lm r - g r ade s i l i c oous or e . 

ulphi de enrichment undoubtedly increaved the t allic c ntent of the or e nea 

e rfa ce . Tiny e .. filled ith "'l..."P 'r en8 c0ve llitc e. plainly i ible in .:tll 

e opes examined . It i cle ar , ho 1ev e r , t a t ulpb.ide enrichme n t has not een 

e chi ef f a tor i n t he forma tion of the tt ~.:: _rade or e s·J.oo t s . o t of the 

of the shoo t , re of hypo ene ori in, a nd h e c c t } ·ir devolo ::1 nt · o. ot 

1.rrace a enc i e . . Th ._up r be c ine r a l s th hoot 

to th ir me t a llic content , pdrti 

App l lo a l c lting or the Al. e da o t 1cc ,ssful . Ti e a po r -

a cc of t e sL1g i dica t cc t:b ... q,t on id.er c..ble ~.!I icult \ a nco mt r e d . "he l ag 

: sony , i"' no t uniform in or.1po~ iti on , nd i .. s~ ot hroUbh it e t a llic glob l 

;; ;d o .. e und i c olve d y ito . According to -~ . vo rt ~/ the co osi t i on of the 

2 wS fr o the Al eda . a ttin ur D.Ce ::1- S <... S follo : 

Compo it ion of l ags f r or lrneda 'urna ce 

l 2 3 4 

SiO 2· ........... .. 30 . 31 . 8 nl . l 38 . 9 

1203 ' ..•........• 10 . 6 13.5 9 . 9 4 .7 

FeO •. . •...•••• •• •• 24 . 9 24 . 0 25 . 3 22 . 3 

aO . •• ••••••... . .• 3 . 1 3 . , I 4 . 8 1 . 3 

Bao •..••••••••••.• 30 . 4 2 .. . 20 . 1 32 . 

~ Diller J ~" · t 8 , • v • , op • c 1 • , p • • 34 
73165 

If a r ea ona ble tonnage of ore of a grade indicated by the anal yses of Holdsrth and Diller can b e demonstra.t e d the h i gher- g r de shoots should rece ive eriou 170 ideration hen me t a l p rices jus tify it, in view of t 'le r e c c-m t imp r ovement s in 

~tJlltrrgy , particula rly in f lota tion . 

Outlying copper dep osits 

Banfi e ld 

The Banfield mine - is about 5 mile s soutlwest of Dre'l , a t £1.n · l titude of 

40 eet . It i s said to ha.v e b e e n loco. t e d as the Rainbow lode , but it i no f 

ge era.lly_ lmown bJ the name of H. Banfi e ld , a forme r owner, who dev e lope d the 

Qeno.sit .. dnring a .. pe-riod of 20 y o rs or mo re a ft -l ' 1900 . A production af 52 t ons 

{ ore conta ining 10 , 059 p olillds of copper a nd 19 ounc s of :::: il ver was r p orted in 

1 28 )_/ In July l 29 a ll ere ·1as emp loye d i n r epairing a concentrat i ng ill 

.near the mine . Acco)r ing t o J. T. Pa rde e, ho visit :- d the i . o a t that t i u , the 

de sit is opene d by sev -.- r a l . adi t s at d iffe r e nt l e v e ls, a nd the '1JJ1dc r g r ound vor_cin&s ar e r a the r ext n~ iv . Th o co1Lntry roc!c i s c} i efl y ~; ton tha t b e lon .. _s to 

t c olde or p r e - Tc rtia Ty roc.tc g roup of 01.1th e stor:n Or ~J Jon . The greenstone i intruded by a body of p orphyry of unde rt e r i ned ext en t . In a zone that trend no rth 

is 20 or 30 feet wide th g r een stone a nd p orphyry a r e bleache d n arly 'hi te by 

id o hermal a lte r n tion . Within this zone chalcopyrite and pyri t e a r e irregula r ly 

d. tri uted as tringe r . , grai.n s , a nd bunc e • The sul p hide s are a ccompani e d 

a dant ma __ ..,ne i t e and , locally , bunche s of q_UD.rtz having a coa r s e t e xt r e li e 

"e .atite . i croscop i c xamination of a spc ci .en of sulphide ore b;yr M. -. Short 

s: s it to co i ""' t chi ufl y of ch:l opyrit e t udde d v ith snall cry. t a ls of mag-

.e ' te . So ae p yrite a l o is p r e s ent . These __ ine r a l 2-.r e cut by v c inl e t of ca r-

, ona e and quartz . 

P e nnell & Far .. w r 

... he pro cpect of P ennell & Fa r me r i s on t h e So· th >-1pqu a ::' ive r a bo ,t l e 

a e i l ler. When ~ee n by r . Pa rdee in J ul-r 1 30 , a lulft eql.lipped " i th p- to -

da e .oi ti g mach ine r y as b e i ng sur. on the no th bank of t he . i ver , p r par a tory 

· e1:p lori ng the de:9 osit ith eros uts i n d. p t h . .1he c ountr ro c, _ co. i t >=> 

largely of dark - r een ho r nblende a nd quartz .:1nd s c s a decided chist ose structure 

t trends northeast ward . S. ll p in_"k: a rnet d.r e p a rinc:,ly s cc>v tt8r e d t h r ough the 

c·-, a d l ocall v much of the horn l nd i a lte r . to chlori t c . H · r c nd t he r e 

f~ a short di..,t nee outcrop e xpo e d lon t e Gtrcam , t lo Nat e ..... c ont in r a ins 

c:.· s ca.ks of lcop rit e G a ri _gly i stributed along t l e cch i tosi t y . Ex e t 

in places the exp os rres of . i e r a lizGd oc a e t1 few ee t wide , tho ext ent 

e depo ·it i no t hown . 

~ Pe r onal com·nurdca t ion fro Vic tor C. He i kes, of t h U. S. Bur au of fines . 

35