HomeMy Public PortalAboutYellow Pine Mining DistrictS. #1
COOKRO, SILBERMAN, BERGER
IDAHO
Figure I. Location map, Yellow Pine mining district.
Introduction
Numerous Au, W, Sb, and Hg mines and prospects occur in the Yellow Pine mining
district in north - central Idaho (Fig. 1). Many of the W, Sb, and Hg mines and prospects
contain anomalous concentrations of gold. The major gold producers have been the following:
Yellow Pine Mine
(1938 -1945)
Cooper (1951)
Meadow Creek Mine
(1932 -1937)
Cooper (1951)
West End Mine
(1982 -1985)
Wolford (oral
comm., 1986)
256,000 oz Au
1,500,000 oz Ag
68,500,000 Ibs Sb
17,300,000 Ibs W03
49,500 oz Au
168,000 oz Ag
7,000,000 lbs Sb
66,000 oz Au
30,000 oz Ag
Most of the Hg from the district was produced at the Hermes Mine (Fig. 2) and
consisted of 15,800 flasks (Minerals Yearbook cumulative data). Anomalous concentrations of
Au occur at the Fern mine (Fig. 2), which produced only a few flasks of Hg.
This study of the Yellow Pine mining district (Figs. 1 and 2) began in 1981, as part of
the Challis 1 °X 2° quadrangle CUSMAP (Conterminous United States Mineral Assessment
Program) project. The first author's primary responsibility has been to study the occurrence
and resource potential for tungsten in the Challis quadrangle. Silberman and Berger studied
the West End gold mine (Figs. 2 and 4) and carried out a reconnaissance geochemical survey
of the district in 1984. Information from both the tungsten and gold studies is combined in
this paper.
�X -]
1 . . j,
YELLOW PINE REINING DISTRICT
Prominent deep - crustal, northeast - trending fault zones (Fig. 3) predominate in the
Yellow Pine district; they probably are related to the inferred trace of a Cretaceous subduction
zone several kilometers to the west, near Riggins, Idaho. Au, W, Sb, and As concentrations
occur within these basement fault zones due to deep circulation of hydrothermal fluids (Fig.
2). Metal concentrations are localized within the faults in granitic rocks of the Idaho Batholith
and metamorphic rocks included in the batholith.
The host granitic and included metamorphic rocks were brecciated and altered in a series
of events. Locally, the rock has been brecciated at least four times. Within brecciated zones,
the rocks are strongly altered to clay and sericite and are permeated with secondary quartz.
Arsenopyrite ( ±gold) occurs primarily in quartz, albitic plagioclase, and adularia veins; i; is
also within fractures of primary grains of microcline and sericitized plagioclase. S- ibnite forms
massive replacements of a calcareous metamorphic rock at the Yellow. Pine Mine, the only
place in the district where it occurs in significant quantities. Stibnite also occurs within
epithermal quartz veins throughout the district. Constituent elements of scheelite and stibnite
were transported by fluids that deposited epithermal quartz veins. Scheelite is present within
quartz of near - surface, low- temperature origin, including colliform bands and epithermal
quartz veins. Scheelite also occurs in clear quartz that is only present surrounding
metamorphic quartz and probably formed as a result of its recrystallization. An important
control on the process of tungsten metallization is the presence of carbonate. Calcite
remobilized from calcareous metasediments and, to a lesser extent, calcite within the
metasedimentary inclusions, act as host to scheelite. The metamorphic and clear quartz grade
into and are cut by epithermal quartz. Tungsten also occurs in strongly anomalous
concentrations (200 -1000 ppm) within jasperoids at the Fern Mine.
Arsenopyrite, scheelite, and stibnite were deposited together in overlapping stages of
metallization; arsenopyrite deposition began first, scheelite deposition was intermediate, and
stibnite deposition continued later than deposition of the other minerals.
Regional Geology
The Cretaceous Idaho Batholith and metamorphic inclusions or large roof pendants of
calcareous rocks, schist, quartzite, and metavolcanic rocks of either Precambrian (Leonard, iYz
Hobbs and Cookro (in press)) or Paleozoic (Ross, 1934) age are dominant rock types of the
region. Pegmatitic and aplitic dikes and quartz veins common in the district are also
Cretaceous in age (Armstrong, 1975, Snee and others 1985). Tertiary felsic to diabase dikes
(Leonard and Marvin, 1982 [19841) are also common. The Thunder Mountain cauldron
complex, composed of Tertiary intrusive and extrusive rocks, is to the east of the district (Fig.
2).
Idaho Batholith lithologies within the Yellow Pine district are either biotite granodiorite,
or porphyritic granodiorite, or muscovite - biotite granodiorite and granite, or leucocratic
granite. Fresh biotite granodiorite is mottled black and white, medium to coarse grained, and
equigranular to porphyritic. Major minerals are sodic to intermediate plagioclase, quartz,
microcline, biotite. Apatite, epidote, sphene, zircon, allanite, beryl, and opaque minerals are
accessory minerals. The porphyritic granodiorite is composed of coarse- to medium - grained
groundmass containing large (5 -10 cm) megacrysts of generally pink poikilitic microcline. The
poikilitic microcline contains anhedral plagioclase, quartz, and biotite; these included minerals
are randomly oriented and some have eroded margins. Plagioclase within the porphyritic
granodiorite, both within megacrysts and adjacent to microcline crystals, is embayed by
metasomatic processes. Sodium metasomatism is evident as plagioclase veining and anhedral
plagioclase grains with randomly oriented quartz and some K- feldspar inclusions. In areas of
Na- metasomatism, plagioclase makes up 90% of the feldspar in the rock. The muscovite-
579
45
I
COOKRO, SILBERMAN, BERGER
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ELK CITY QUAD
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ROCK DESCRIPTIONS
Challis —1 —rvics
vPink gramt< and quart: monzanfre
-Tdc Dionne complex
r/f Tertiary dikes
Klg Leurocratic granite
`' Kg Muscovite btotfle grandodionte and granite
Kpd Brwite grandodiorite .i
Kgdp Porpirtienic biotfte grandodioritr and granite
Kim Mixed rock
Kgmf Foliated quartz monronite
Idaho batholith undiNerentiated
ED Metamorphic inclusions ivithfn the batholith of uncertain age
Velfoopine Mining District
Fast
Kim I Mapping h..m Mnchelf. V E and Bennett. E H. 11979,. and Fisher.
F S Mtlnn,.i D H and Jnhnson K M.(14H31
mu
Kgdp
f Td,
Kgd�p1')R It _
Kgd Kgd p
mu
KgdpTdc
mu
Hrlated mmeraluaoon along the nosh to north -east trending faults
Werd_h." Prospect IC-. Au. Zn. Pb. Ag. Sb W)
2 McRae Mine Red Bluff Mme (W, Zn. Pb. Cu. Ag)
Neu Sno hnd Mine (W. Zn Pb Cu. A91
:3 Independence Prospect IF Au. Zn. Hg. Pb. Cu. Ag. Be. W)
4 Annmom Rainbow. Mme IC.. Sb. W Au)
5 Golden West Mine (Sb. W. Auf
6 1 udwig Depus4 IPb. Zn. Cu. Au. Ag W Sbi
7 Wilson Group IAu. Zu. Ph. Sb Cu. A91
H Quartz Creek Mme (W. Sb. Au Ag)
9 Golden Gate Occurrence IAu. Ag. W. Shl
10 Yellow Pine Mine f W. Sb. Au, Ag Hg)
11 Sufbde •10 prospect (W)
12 Meadow Creek Mine IAu. Ag, Sb. Cu. Mu)
13 West End Mme (Au)
14 Hermes Mrne fHg. As. Sb)
1S Fern Mine IHy
16 Mule Train ("14 ", IA- Ag Cu Ph. W)
17 Mein Blur Mine IAu F WI
Figure 2. Regional geologic ma
northern bordrr p of the Yellow' Pine mining district and vicinity. The open circle on the
of the district is the town Of Yellow Pine.
Description of Map Units
Rock descriptions are largely extracted from Fisher and others, (1983) for the Challis uadran 1
Mitchell and Bennett (1979) for the Elk City quadrangle and Leonard (written Comm., 1986) for the Yellow
Pine district itself. These descriptions have units contained in Figs. 2 and 4. q g e and
Qd MAINLY GLACIAL DEPOSITS AND ALLUVIUM (Quaternary) - -Includes mill taili
Meadow Creek and talus and landslide debris ngs along
Tv CHALLIS VOLCANICS (Eocene) —Units include rhyolite, latite, ruff, megabreccia, and rhyolite tuff
580
YELLOW PINE MINING DISTRICT
Tg PINK GRANITE AND QUARTZ MONZONITE (Tertiary) — Hornblende, granite, and granophyre
Tdc DIORITE COMPLEX (Tertiary) —Suite of non - porphyritic diorite to porphoritic granodiorite
characterized by hornblende, euhedral biotire, and magnetite which make up < 35% of the rock.
Where present, phenocrysts are zoned plagioclase and pale -red perthitic microcline (up to 1 cm in
length). Quartz phenocrystsare rare, rocks weather to chocolare -brown soil
Td DIKES OF INTERMEDIATE COMPOSITION (Tertiary)
Ki IDAHO BATHOLITH UNDIFFERENTIATED (Cretaceous)
Kim MIXED ROCK (Cretaceous)— Includes rocks that range in composition from biotite granodiorite to
alaskite (or leucocratic granite) phases of the Idaho batholith along with included metamorphic rocks
(described below as mu, muq, and muc)
Klg LEUCOCRATIC GRANITE (Cretaceous) —Light -gray to white, fine- to medium - grained granite
having distinctive anhedral texture. Principal minerals are quartz, K- feldspar and plagioclase f
garnet t minor (<2 %) biotite. Feldspars are altered to sericire and small flakes of muscovite. We
believe some of the fine - grained aphanitic 'leucocratic granite" or "alaskire" has an altered texture
due to hydrothermal alteration along the north- to northeast - trending faults, biotire has been leached
out and secondary silica has been introduced
Kg MUSCOVITE BIOTITE GRANODIORITE AND GRANITE (Cretaceous) —Gray to light -gray,
medium- to coarse - graained, equigranular to porphoritic granodiorite; contains books of muscovite
that are visible in hand specimen and make up as much as 5% of the rock It is considered by Fisher
and others (1985) as the younger "core" of the batholith. Note a vague alignment of this unit along
the north- northeast faults
Kgdp PORPHYRITIC BIOTITE GRANODIORITE AND GRANITE (Cretaceous) — Coarsely porphyoritic
granitoid rock containing metacrysts of pink microcline 3 -10 cm long in medium- to coarse - grained
matrix containing equal amounts of microcline, plagioclase, and quartz with 5 -15% biotite t
hornblende
Kgd BIOTITE GRANODIORITE (Cretaceous) —Gray to light -gray, medium -to coarsegrained and
equigranular to porphyritic rock. Plagioclase (Au22-30) quartz and potassium feldspar are the major
minerals with biotire and rare hornblende. This unit is the dominant rock of the Idaho batholith.
Locally intruded by alaskire and small dikes of aplite and granite pegmatite
Kig GARNET - BEARING BIOTITE GRANODIORITE (Cretaceous)— medium to coarse - grained,
commonly with a somewhat curly foliation. Garn,*is sparse; muscovite is rare; sillimanite, present
locally, is microscopic. Locally intruded by alaskire and granite pegmatite
Kgmf FOLIATED QUARTZ MONZONITE — (May be Precambrian in age)
mu METAMORPHIC INCLUSIONS WITHIN THE BATHOLITH (Precambrian or Paleozoic) —These
undifferentiated rocks have disputed ages. They have been described both as Paleozoic and
Precambrian, Larsen and Livingston (1920), Ross (1934), Shenon and Ross (1936), White (1945),
Leonard (1973). The most recent description is by Leonard (written comm., 1986): The Yellou.jacket
Formation in the Yellow Pine area is broadly divisible into three parts. In ascending order these are
(1) argillite - siltite unit, several thousand feet thick, base not exposed; (2) carbonate unit, thickness
perhaps 150 -750 m (500 -2,500 ft); and (3) metavolcanic unit, thickness perhaps 150 -600 m (500-
2,000 ft). Prebatholith deformation, syn- batholith deformation and metamorphism, faulting, regional
strain, and younger blockfaulting leave thicknesses in doubt and require descriptions of the
Yellowjacker in metamorphic terms. The argillite - siltite unit is composed of alternating laminae of
argillite and siltite, commonly gray to black, locally green, slightly calcareous, with some thin beds of
massive argillite and quartzite. Carbonate rock includes marble with disseminated diopside, epidote,
or phlogopite; tremolite schist, locally diopsidic. Amphibolite, and a trace of metamorphosed welded
rhyolite ruff are present in the medium -grade metamorphic zone. Amphibolite and felsic biotite
hornfels are common in the high -grade zone; remnants of welded tuff and volcanic breccia are rare.
The Hoodoo Quartzite is a massive, fine- to medium - grained very light colored quartzite. Feldspar,
mostly microcline and orthoclase, but with different amounts of albite, ranges from 5 -10 percent of
the rock, and muscovite, sericire, and chlorite may range from 0 -10 percent
muq WHITE QUARTZITE —early pure, locally with a little biotite. Includes coarse conglomerate of Sugar
Creek, Cinnabar, and Fern areas
muc LIMESTONE, DOLOMITE, SKARN, SCHISTS AND METAVOLCANIC ROCKS — (biotite hornfels
and biorite- quartz - feldspar schist)
WE
Er
COOKRO, SILBERMAN, BERGER
biotite granodiorite and granite are identified in the field by the presence of books of
muscovite rather than single flakes. It is considered (Fisher and others, 1983) as the younger
core of the batholith. This youngest unit of the batholith at the surface (note on Fig. 3)
crudely aligns along or is on strike with the northeast - trending regional faults. Because the
faults were active during the Cretaceous, rocks that were emplaced as later phases of the
batholith probably coalesced along the faults. The leucogranite is light -gray to white, fine to
medium grained with a distinctive anhedral texture. Some of the leucocratic granite in the
western part of the Yellow Pine district (dashed lines on Fig. 2), is actually altered rock of the
batholith. The leucocratic unit crops out on the Deadwood -South Fork of the Salmon fault,
which is also called the Johnson Creek fault, and altered rocks of the batholith commonly
occur in the region. Aplite and pegmatite dikes and segregations related to the Cretaceous
batholith are abundant, particularly in the vicinity of the Yellow Pine Mine. The dikes consist
of fine to coarse, subhedral to anhedral grains of K- feldspar, quartz, and plagioclase. K-
feldspar phenocrysts, incorporating earlier plagioclase and quartz, are present in the
pegmatite dikes. Biorite, muscovite, and beryl are present in places. The aplite and pegmatite
dikes are fractured and veined with quartz and calcite.
Blocks of metamorphic rocks within the batholithic terrane (Cooper, 1951) are quartzite,
mica schist, marble, and skarn, and according to Leonard (unpub. data, 1985) include argillite-
siltire, carbonate, and metavolcanic units. At the Yellow Pine and West End mines,
metamorphic pendants are composed of andalusite phyllite, staurolite -mica schist and
116°
45 r
114`
Y PANTHER CREEK 1
V 2 GRABEN
N THUNDER MOUNTAIN
O ~ CAULDRON
O J COMPLEX
i
I
I
i
VAN HORN PEAK
CAULDRON
COMPLEX
TWIN PEAKS
/ CALDERA
KNAPP CREEeGRABEN" OChallis
GJ
OStanley
^EXPLANATION
'^ FAULT — Bar and ball
DEER PARK FAULT 7( on downthrown side;
a
BEAR RIVER FAULT arrows show lateral
movement
0 t0 10 MMES - - -- — — -
0 10 :0 [00METERS
Figure 3. Map of the Challis I OX quadrangle showing principal faulrs, grabens, cauldron complexes and
caldera, from Kiilsgaard and Lewis ( 1985) with the addition of the Meadow Creek fault zone.
582
YELLOIY' PINE MINING DISTRICT
sillimanite - biotite schist, and a marble unit that consists of calcite, quartz, phlogopite,
tremolite, and garnet (Fig. 4). The skarn is intercalated in quartzite sequences. Minor
amphibolite is included within this sequence. A good exposure of amphibolite occurs along the
access road to the Yellow Pine Mine (sample site Y -9, Fig. 4).
Tertiary dikes ranging in composition from rhyolite to diabase are present within the
district, and extrusive rocks of the Tertiary Thunder Mountain cauldron complex are exposed
east of the district (Fig. 4). The rhyolite and quartz latite Tertiary dikes are light colored and
have a very fine grained groundmass. Latite (called lamprophyre) and diabase dikes are
younger than the more felsic dikes (Cooper, 1951 ), and they contain biotite and plagioclase
phenocrysts, respectively. Opaque minerals are common in the mafic dikes. Extrusive Tertiary
rocks of the Thunder Mountain cauldron complex, just east of the Yellow Pine district, were
first recognized by B. F. Leonard iCater and others, 1973; and Leonard and Marvin, 1982
1 1984 ).
Regional Structure
On the western side of the Challis quadrangle (Fig. 3), the dominant structural pattern is
formed by north -south to N. 300 E.- trending faults that are regional in extent and can be
traced for more than one degree latitude. The faults are upthrown on the west (Kiiisgaard and
Lewis, 1985) and have a right - lateral component because the major stress was directed from
the southwest. East of the north - trending fault set is another set of major faults trending N.
300-60° E. (Fig. 3, the trans - Challis fault system), possibly resulting from earlier stress
directed from the northwest.
Stratigraphic markers along the faults are rare because the faults are in plutonic rocks.
Kiilsgaard and Lewis (1985) developed a general stratigraphy in the batholith and determined
that the western side of the Deadwood fault zone was upthrown several kilometers relative to
the east side. Right - lateral movement is known from the secondary fracture patterns. Where
the main faults splay to the east (Fig. 5), the fault intersection has an extentional, open -space
component, which is important because these intersections localize the mineral deposits.
The two north - trending faults important in this discussion of alteration and mineral
deposits are the Deadwood -South Fork Salmon fault and the Meadow Creek fault zone (Fig.
3). The latter is host to the W- Au -Ag -Sb mineral deposits of the Yellow Pine Mine. The West
End Mine is located along a northeast- trending splay related to the Meadowcreek fault system
in which the Seeing Eye fault (Leonard, 1973b) is a north - trending shear set. The granodiorite
of the Idaho Batholith was strongly brecciated along the faults within a zone as much as 1 -1.5
km wide (Leonard, 1983). Circulating fluids caused major textural and chemical changes in
these brecciated areas. The length of the faults and width of alteration along them suggest
that the faults extend deep into the crust, providing conduits for continued circulation of
heated fluids.
The presence of paleo -hot springs and a few active hot springs along the regional faults
also suggest that the faults are deep- seated. Cross - cutting relationships of scheelite- quartz and
quartz -only veins at the Yellow Pine Mine and the Golden Gate Mine shows several stages of
fault movement. The evidence suggests that silica deposited from the fluids moving along the
faults locally plugged the fractures until subsequent fault movement broke the seal and fluid
flow continued until the area became clogged again.
Alteration
Along the north- to northeast - trending shear zones, the original medium- to coarse -
grained biotite granodiorite and porphyritic granodiorite of the batholith (Fig. 6) have been
583
440
52'
30.,
COOKRO, SILBERMAN, BERGER
115 °20'
0 1 KILOMETER
Figure 4. General geology and sample locations —the Yellow Pine mining district from B. F. Leonard
(written comm., 1985) and D. E. White (1945). Base map: Stibnite, Idaho 7'h minute quadrangle. See Fig. 2
for rock descriptions. The dashed line is the Meadow Creek fault and the numbers are sample locations.
strongly argillized, silicified, and sericitized. Fine - grained clay and secondary silica permeate
the altered batholith, giving the altered granitic rock a much finer grained appearance than
when fresh (Fig. C). Megascopically, the mottled medium- to coarse - grained rocks, either black
and white, or black, pink and white, become a very homogeneous looking light -tan to brown
to gray where altered. The altered granodiorite, because it lacks mafic minerals and is fine
grained, is sometimes called alaskite, or aplite, or leucocratic granite in the literature.
ijb: , . - -- ,.
YELLOW PINE MINING DISTRICT
Key to Mine and Sample Locations for the Yellow Pine District Map
(See Appendix A for sample descriptions)
Location Description
1 Yellow Pine pit, granodiorite - sample Y2
2 Yellow Pine pit, Au zone - Y1 series samples
3 Yellow Pine pit, W and Sb zone - Y3 series and Y4 series samples, and
samples M002, MO10, M032, M034, M0113, M0130
4 Background samples - Y7 series samples
5 Background sample - sample Y19
6 West End Main pit - Y8 series samples
7 West End Upper pit - Y5 series samples
8 Background sample - sample Y21A
9 Background sample - sample Y11
10 Background samples - Y12 series samples
11 Background sample - sample Y10
12 Background samples - Y9 series samples
13 Background sample - sample Y13A
14 Background sample - Y18 series samples
15 Hermes mercury mine
16 Background sample - sample Y17
17 Background sample - sample Y15
18 Background samples - Y16 series samples
19 Fern mine (Hg) - Y14 series samples
20 DMEA prospect (also called Sulphide #10) - Y6 series samples
21 Meadow Creek mine (gold, silver and antimony)
22 Bonanza prospect - Y20 series samples
Figure 5. Diagram of fault refraction and shattering within the Idaho batholith, and mineralization via infill
and replacement (modified from Pollard and Taylor, 1985).
585
COOKRO. SILBERMAN, BERGER
Figure 6. Coarse - grained unaltered biotite granodiorite (upper left) of the Idaho Batholith, granodiorite after
extreme alteration (lower right) caused by faulting, argillization, silicification, and sericitization. The altered
rock is light tan to light grey, fine grained, vuggy, and oxide -rich.
Secondary silica, in veins and disseminations, is the most pervasive alteration of the district; it
has replaced and permeated the rock within the fault zones, where in places the silica makes
up greater than 9017c of the rock. Quartz occurs in stockwork veins and veinlets, as
disseminations, in colliform bands, and with reticulate textures. Vugs formed by leaching of
feldspar grains or formed in extensional fractures are either partially filled with euhedral
quartz ± scheelite ± gold and commonly with Mn and Fe oxides or they are completely filled
with secondary quartz, forming a quartz -eye pattern in the rock.
Plagioclase is sericitized; fine flakes of sericite are common although they are lacking in
some of the mineralized zones. Feldspar grains are commonly argillized in the fault zones.
Clays minerals that formed from the alteration of feldspar grains are commonly leached out,
and the resulting void is filled with euhedral clear quartz. These altered silicates were no
doubt an important source of the secondary silica within the altered plutonic rocks.
Dark biotite grains in unaltered granodiorite are only remnant shreds in the altered
rocks, or they have been recrystallized to either chlorite + fine mica and opaque
minerals ±sphene, -.or epidote ±calcite and opaque minerals. The most common opaque
minerals occurring in replaced biotite are arsenopyrite, pyrite and pyrrhotite.
Calcite occurs as discreet grains in inetasedimentary inclusions within the batholith, and
as crystalline calcite in veins and breccia infillings. The calcite veins and fillings are probably
hydrothermal in origin. The hydrothermal ( %) calcite is sometimes dark in color and contains
Mn and Fe oxides and abundant opaque minerals, which include fine grains of arsenopyrite
and pyrite. This type of calcite is preferable to the calcite within metamorphic rocks for
replacement by scheelite; it was more massively replaced and resulted in very high grade
tungsten ore.
586
YELLOW PINE MINING DISTRICT
Occurrence of Gold
Submicron -sized gold occurs within sulfides (pyrite, arsenopyrite and stibnite) and as free
gold. The more favorable ground for mining is in the oxidized zones, like that of the West
End Mine, versus the less amenable ground of the sulfide -rich Yellow Pine Mine. There is
some evidence for several phases of gold mineralization in the district. Arsenopyrite and
pyrite, presumably deposited in an early phase, are disseminated within slightly altered
granodiorite and may contain gold. Cooper (unpub. data, 1949) describes some of the gold ore
in the Yellow Pine pit as being in "comparatively little altered quartz monzonite." This
siightly altered granodiorite was both Na- and K- metasomatized, and veins of albitic
plagioclase and adularia are common. Arsenopyrite and clusters of fine pyrite grains with
altered cores are commonly included in plagioclase, less commonly in adularia veins and along
fractures in K- feldspar grains within the gold zones. The sample with the highest gold
content is from the gold zone of the Yellow Pine Mine and came from a quartz vein that cuts
sericitized and mineralized granitic rock. The vein contains abundant very fine - grained pyrite,
arsenopyrite and other indistinguishable sulfides. Within the ore zones, biotite is often
replaced by arsenopyrite, pyrite and pyrrhotite, and calcite veins contain arsenopyrite and
pyrite grains. Whether the gold was deposited in early and late phases or was continuously
being deposited is currently unknown.
Within and in the vicinity of the Yellow Pine Mine, gold occurs as native gold (White,
1940), in the minerals arsenopyrite and pyrite, and in the zones of the pit having high
concentrations of stibnite and tungsten. (Cooper, 1951). Cooper (unpub. data, 1949) reports
arsenopyrite having a consistent ratio of 0.05 oz. gold to 1 percent arsenic in the Yellow Pine
Mine. Chemical data also suggest a strong correlation of gold with arsenic. There is also
evidence of a gold association with antimony in the stibnite zone of the Yellow Pine pit
(Cooper, 1951). It has not been determined how the gold occurs with or within the stibnite,
but it is with this sulfide and not just with disseminated arsenopyrite in the stibnite zone.
At the West End Mine, mineable concentrations of gold occur within fractured, oxidized
metasedimentary rocks of a roof pendant within the batholith. Geochemical anomalies
reported by Cooper (1951) and later followed up by a soil sampling program by Leonard
(1973b) led to exploration and development of the mine by Superior Mining Company. The
property was recently acquired by Pioneer Metals. Although quartzite and mica schist are the
most favorable host rocks, all lithologies sampled in the upper and lower pits contain
anomalous concentrations of gold. Submicron -sized native gold, which occurs along fractures
and disseminated, throughout the strongly oxidized and fractured rock, makes up the ore
(Lasmanis, 1981). Lasmanis (1981) described the protore as auriferous arsenopyrite, which is
present at lower elevations in the Yellow Pine pit. Auriferous arsenopyrite is not observed in
the mine workings or, thus far, by ore microscopy from samples collected at the Yellow Pine
or West End Mines. Dikes of porphyritic dacite or latite are present in the mine area and
contain stockwork quartz - sulfide veins; the dikes are also within the ore bodies (Lasmanis,
1981).
Occurrence of Tungsten
Scheelite occurs as (1) fine to coarse crystals replacing calcite (Figs. 7a and 7b), (2) solid
inclusions in quartz veins (Fig. 7a and 7b), (3) fine coatings on rock fracture surfaces, mixed
with fine - grained quartz, and (4) clay -sized euhedral to subhedral crystals on manganese
oxides. Type 1 crystals occur within the W ore zone of the Yellow Pine pit where tungsten -
bearing quartz veins are in contact with calcite. The calcite is either hydrothermal calcite
filling in the matrix of breccias, or in metasedimentary breccia clasts. Altered granitic rocks
having high tungsten content have been strongly fractured and the quartz - scheelite veins fill
587
COOKRO, SILBERh1AN. BERGER
these fractures. The high -grade tungsten zone of the Yellow Pine pit contained coarse
scheelite crystals replacing hydrothermal calcite cut by quartz feeder veins. Coarse scheelite
crystals occurring in calcite- bearing metasedimentary inclusions are scattered around the
margins of the inclusions and near quartz veins, but the scheelite replacing the hydrothermal
calcite results in extremely high grade scheelite ore.
Type 2 crystals occur in rungs ten -bearing zones in the Yellow Pine pit, the West End
Mine and the DMEA property (also called Sulfide #10) and are common throughout the
district. Some tungsten- bearing quartz veins contain mostly clear quartz, but the quartz
containing arsenopyrite or stibnite has a gray color. The tungsten- bearing quartz veins and
tungsten- bearing calcite and calcite veins are interwoven. Where the rungs ten -bearing quartz
Figure 7a and b. Tungsten ore from the Fellow Pine Mine. Scheelite within quartz veins (solid inclusions)
and replacing calcite (the nearly pure white areas in photo b) in the breccia matrix. a: in ordinary light, b: in
ultraviolet light showing fluorescing scheelite.
588
rt�
YELLOW PINE MINING DISTRICT
veins contact the hydrothermal calcite, calcite is massively replaced by scheelite; where calcite
veins and quartz veins are in contact with each other, scheelite crystals often develop within
the calcite veins with their c -axis parallel to the contact.
Type 3 scheelite crystals, which are common in the district, occur on fracture surfaces.
These very fine - grained crystals occur with quartz as films on open rock fractures; they are
rarely present on fracture surfaces in Tertiary dikes. Type 3 crystals occur within layers of
colliform bands between quartz layers. It is possible such scheelite is being deposited at
present, as it fills slight surface depressions in rock joints that host a nearby active hot spring.
The water in this hot spring on Hot Creek has anomalous (6 ppm) tungsten concentrations
(B. F. Leonard, oral comm., 1982).
Type 4 scheelite crystals occur on a punky mixture of Mn and Fe oxides and
cryptocrysta I line quartz. This mixture resulted from dissolution of Mn- and Fe- bearing
remobilized calcite, probably by acid fluids. Clay -sized euhedral to subhedral crystals of
scheelite cling loosely to the manganese oxides (Cookro, unpub. data, 1987; Petersen, 1984).
In hand specimens, a slight dusting of tiny scheelite crystals occurs on the oxides.
Although it has been previously noted that the Tertiary dikes are associated with the
tungsten ore bodies (Cooper, 1951), tungsten content actually drops off in the vicinity of the
dikes. In one place, however, scheelite was observed to extend into a fracture within a dike of
Tertiary age. The scheelite at the New Snowbird Mine (Fig. 2) was in a tiny 1 -3 mm fracture
that crossed into the dike which demonstrates that scheelite deposition continued after the
emplacement of the Tertiary dikes.
Scheelite occurs around altered breccia fragments of granodiorite to which quartz has
been added and in which the mafic minerals are mostly replaced. In places the breccia
fragments are hardly visible in hand specimen unless an ultraviolet light highlights blue -white
fluorescing scheelite. The scheelite occurs in quartz veins and calcite veins in several
superimposed stages of brecciation and tungsten mineralization.
Isotopic Relationships
Regional light stable isotopes and K -Ar ages
Light stable isotope (oxygen and hydrogen) measurements of samples from the Atlanta
lobe region of the Idaho Batholith by Criss and Taylor (1983) demonstrated that meteoric -
water- dominated hydrorhermal systems of regional extent were centered upon and generated
by Eocene intrusions (37 -46 ma) and caused significant isotopic exchange in silicate minerals
of the Cretaceous granitic rocks. 160/160 was strongly lowered in feldspar and biotite and
slightly lowered in some quartz (quartz is more refractory to oxygen isotope exchange than
other silicates). D/H was strongly lowered in biotite and slightly lowered in muscovite.
Regional K -Ar data of Criss and others (1982) shows a good correlation between reset
biotite K -Ar ages (due to argon loss) and areas of depletion of 180 and D. They also illustrate
that a strong correlation exists between the occurrence of Au -Ag mines and prospects and the
boundary zones of the meteoric - hydrothermal systems. This implies that many of the deposits
were formed during the Eocene (Criss and Taylor, 1983, p. 659). The occurrence of Au -Ag
deposits in volcanic rocks of Eocene age, such as at Yankee Fork, Thunder Mountain, and
elsewhere in the region (Hardyman, 1985; Criss and Taylor, 1983, McIntyre and Johnson,
1985; Manghan, 1984) corroborates this implication. The Yellow Pine district fits this pattern
as it occurs along one of the boundary zones of a large meteoric - hydrothermal system (Criss
and Taylor, 1983). However, recently published 40Ar /39Ar spectrum ages of sericite and
adularia from several Au -Ag districts in the batholith and from metamorphosed roof pendants
(Lund and others, 1986; Snee and others, 1985; Gammons and others, 1985) are Late
Cretaceous and correspond to late -stage intrusive activity of that age in the batholith.
589
i
COOKRO, SILBERMAN, BERGER
K -Ar ages at Yellow Pine
A single 40Ar /39Ar spectrum age determination of sericite from a sample collected at the
Yellow Pine Mine (L. W. Snee, written comm., 1986) is also Late Cretaceous. However, three
conventional K -Ar age determinations from replacement adularia collected from the Au ore
zone yielded an average age of 57 ±1 ma (Lewis, 1984), which is older than the Eocene event
but much younger than the Cretaceous alteration age. K- feldspars are more susceptible to
argon loss, measured by conventional K -Ar techniques, than muscovite during post
crystallization thermal events (Dalrymple and Lanphere, 1969; Evernden and Kistler, 1970;
Hart, 1964; Harrison and others, 1979). We suggest that the feldspar ages could represent
partial argon loss from an original Late Cretaceous crystallization event. Similar relationships
of sericite and K- feldspar (where the K- feldspar was reset by subsequent events) is
demonstrated at the Getchell disseminated, sediment - hosted gold deposits in Nevada
(Silberman and others, 1974). Criss and others (1982) show a diagram contouring apparent
K -Ar biotite ages in the region, which were reset during the Eocene meteoric - hydrothermal
event. The 60 ma contour passes close to Yellow Pine; thus, it appears likely that Yellow Pine
was thermally affected by that event. Additional K -Ar analyses, particularly 40Ar /i9Ar
spectrum measurements on a variety of original and alteration minerals at Yellow Pine are
necessary to clearly establish the thermal history.
Y-5(1) West End Mine -upper pit
granitic dike, sericitic Quartz (vein) +12.3 -1002
alteration, stockwork
quartz veining Muscovite (primary) + 8.3 -83
Y -84 West End Mine -lower pit Quartz (host rock) +13.8 -942
brecciated, oxidized Quartz (vein) +13.9 -1112
quart-zite ore, stockwork Muscovite (detrital) +10.4 -84
quartz veining
Y -18 Roof pendant in batholith Quartz +12.4 -114=
pyritic, micaceous
quartzite
' Relative to SMOW
z From crushed fluid inclusions
590
Table 1
Stable isotope data from the Yellow Pine Mining District,
Valley County,
Idaho
Sample Setting
Mineral
d1800 /00'
dD1800 /00'
Y -1 Yellow Pine Mine
Quartz (host rock)
+12.4
-1042
Au zone, sericitic
Quartz (vein)
+16.8
-1002
alteration — stockwork
Sericite
+12.0
-84
quartz - veined granitic rock
Y -3A Yellow Pine Mine
Quartz (host rock)
9.8
-842
Sb zone, sericitic
Sericite
+ 9.0
-79
alteration, silicification
Y-5(1) West End Mine -upper pit
granitic dike, sericitic Quartz (vein) +12.3 -1002
alteration, stockwork
quartz veining Muscovite (primary) + 8.3 -83
Y -84 West End Mine -lower pit Quartz (host rock) +13.8 -942
brecciated, oxidized Quartz (vein) +13.9 -1112
quart-zite ore, stockwork Muscovite (detrital) +10.4 -84
quartz veining
Y -18 Roof pendant in batholith Quartz +12.4 -114=
pyritic, micaceous
quartzite
' Relative to SMOW
z From crushed fluid inclusions
590
YELLOW PINE MINING DISTRICT
Light Stable Isotopes at Yellow Pine
A reconnaissance survey of oxygen and hydrogen isotopic ratios in quartz, quartz veins,
and sericite was made in the district. Samples included a variety of mineralized rocks from the
Yellow Pine and West End Mines and a sample of unaltered quartzite from near the Fern
Mine. The isotope results are summarized in Table 1. A summary of oxygen and hydrogen
isotope data from the Atlanta lobe region of the Idaho batholith (Criss and Taylor, 1983) and
of other relevant rocks and minerals is included in Table 2.
Oxygen Isotopes
The oxygen isotope composition of host -rock quartz from altered granitic rocks,
containing younger quartz veins, at Yellow Pine is not distinguishable from that of fresh
granitic rock of the Idaho batholith. The 5180 values of quartz from mineralized quartzite at
the West End Mine and from unmineralized quartzite near the Fern Mine are both slightly
higher than that of typical quartzite of eastern Nevada (no background data are present from
the Idaho batholith region outside the Yellow Pine district) but is within the range of
quartzite in general (Lee and others, 1985; Epstein and Taylor, 1968). Quartz is more
refractory to oxygen isotopic exchange than other silicates (Criss and Taylor, 1983; Taylor,
1968).
Background data do not exist for oxygen isotope compositions of igneous muscovite in
this region. 5t80 values for sericite and muscovite from altered igneous rocks at Yellow Pine
are similar to values for unaltered igneous rocks from the Basin and Range province and for
sericite formed by deuteric processes in the Basin and Range rocks (Lee and others, 1984;
Tables 1, 2).
The host -rock quartz, muscovite, and sericite at Yellow Pine do not appear to have
undergone isotopic exchange with a heated, dominantly meteoric water (46150 depleted). In
contrast to the minerals at Yellow Pine, sericite and quartz formed by alteration at Butte,
Mont., from the action of heated, dominantly meteoric water are variable, but have many
strongly 180 depleted values; the sericite shows extreme D depletion. Most of the Yellow Pine
district was mineralized at much lower temperatures than the Butte district (T. M. Cookro,
unpub. data, 1987; Cookro and Silberman, 1987) and, therefore, comparatively less isotopic
exchange would be expected.
Quartz from stockwork veins at the Yellow Pine and West End Mines appear to be
slightly enriched in 110 relative to unaltered rocks in the region (Tables 1 and 2). Criss and
Taylor (1983) noted a large range of S 180 in quartz veins hosted in granitic rocks of the Idaho
batholith. They indicated that high 51110 characterized veins near Au -Ag mines. Oxygen
isotope ratios from Yellow Pine are typical of those found in metavolcanic and
metasedimentary rocks such as those found along the Mother Lode belt of California, and in
southern Alaska gold vein deposits (Table 2).
On the basis of the similarity of oxygen isotope composition of veins at Yellow Pine to
those listed in Tai le 2, fluids that deposited them appear to have the oxygen isotope
characteristics of metamorphic or igneous origin, or at least they have undergone extensive
high - temperature exchange with metamorphic rocks (Kerrich and Fryer, 1979; Bohlke and
Kistler, 198T)). This is inconsistent with petrographic, textural and fluid- inclusion evidence
which was presented by Cookro and Silberman (1987). The difficulty in separating the
metamorphic or igneous quartz of the district from the overprinted late, shallow environment
quartz may cause this apparent inconsistency.
Hydrogen Isotopes
The 46D values of sericite and muscovite from altered granitic rocks and quartzite ore
from the Yellow Pine district are tightly clustered in the range of -79 to -84 permil. This is
abour 20 -30 permil lighter than 5D of muscovite from unaltered granitic rocks in the rest of
591
COOKRO, SILBERMAN, BERGER
Table 2
Summary of isopotic results on rocks and minerals from Yellow Pine Mining District,
southern part of the Idaho Batholith, and related rocktypes. ( - -) indicate no data.
Mineral Setting d180 D Reference
Quartz
Unaltered granitic
+9 to +12
--
Criss & Taylor
rocks, Idaho batholith
(10.2 + 1,3)
(1984)
Quartz
Quartz veins in
-6.2 to +14.6
--
batholith
K- Feldspar
Quartz veins in
8.2 to +10.6
--
Criss (1980)
batholith
Muscovite
Quartz veins in
--
-50 to -60
Criss & Taylor
batholith
(1983)
Muscovite
Plutonic rocks
8.2 to 11.0
-60 to -70
Lee & others
eastern Nevada,
(1984)
southern Basin & Range
Sericire
Deuteric alteration of
9.6'to 11.1
-67 to -86
"
feldspars, in above
Quartz
Yellow Pine Mine,
7.1 to 10.1
--
Lewis (1984)
K- feldspar alteration
Gold zone
Quartz
Fern Mine, hypothermal
11 to 15
--
Lewis (1984)
Adularia
Yellow Pine Mine, K -feld-
5.2 to 7.7
--
Lewis (1984)
spar alt., gold zone
Sericite
Yellow Pine Mine, K -feld-
5.4 to 11.6
--
Lewis (1984)
spar alt., gold zone
Granitic
Unaltered, Yellow Pine
6.9 to 9.4
--
Lewis (1984)
rock
Mining District
Granitic
Altered, K- feldspar,
rock
early gold phase
8.0 to 9.9
--
Lewis (1984)
Quartz
Quartzites, eastern Nev.
10.2 to 11.8
--
Lee & others
(1984)
Muscovite
Quartzites, eastern Nev.
7.5 to 10.5
-60 to -81
Lee & others
(in press)
Quartz
Veins & replacement
+15.9 to +21.7
--
Bohlke &
quartz in altered rock—
Kistler (1986)
Mother Lode, Calif.
Quartz
Veins in Dome Mine
+14 to +15
--
Kerrich &
Porcupine Dist., Canada
Fryer (1979)
Quartz
Metasedimentary & granite
+13 to +18
--
Mitchell &
hosted, southern Alaska
others, (1981);
M.L. Silber-
man, unpub.
data, 1985
592
YELLOWY' PINE MINING DISTRICT
the Idaho Batholith (Criss and Taylor, 1983; Table 2). The Yellow Pine SD ranges overlap
those of sericite formed by deuteric alteration of feldspar in granitic rocks of eastern Nevada,
which themselves have SD values 10 -20 permil lighter (depleted in D) than those of
unaltered rocks (Lee and others, 1984; Table 2). The D/H data suggest some isotopic
exchange between the sericite at Yellow Pine and heated D- depleted fluid, such as meteoric
water. Eocene meteoric water in this region had isotopic compositions of approximately -110
SD and -15 permil ,3180 (Criss and Taylor, 1983). Isotopic equilibration between the muscovite
and sericite at Yellow Pine and a fluid of this composition must not have been complete,
otherwise the muscovite and sericite SD would have been considerably lower at any probable
temperature of interaction (see Table 2 of Criss and Taylor, 1983), as would their 6"0 values.
The presence of a strongly D depleted fluid at Yellow Pine is also indicated by low SD
values of fluids released by crushing and vacuum extraction of fluid inclusions from quartz
from veins and host rocks (Table 1). The vein quartz in particular has consistently low SD,
-100 to -111, which is identical to the value calculated for Eocene meteoric water by Criss and
Taylor (1983). &D values of quartz from host rocks, on the other hand, vary widely. The
higher SD values overlap those characteristic of magmatic or metamorphic fluids (Taylor,
1974) and may indicate the crystallization of quartz in its original environment.
We consider it probable that heated Eocene -age fluids of meteoric origin circulated at
Yellow Pine, as the reset K -Ar feldspar ages (Lewis, 1984) suggest, and as the correspondence
of fluid SD values with those that would be expected for Eocene water in the vein quartz
corroborates. Temperatures of mineral deposition, for the most part, were low (less than 200°
C) as suggested by the epithermal and textural characteristics of the late quartz, by fluid
inclusions, by the lack of oxygen isotopic equilibration between fluids of this composition and
the quartz, sericite and muscovite, and by the suggested partial hydrogen isotopic exchange of
the sericite. Petrographic and fluid - inclusion surveys suggest a deep plutonic or metamorphic
environment for only some of the sphalerite, a trace mineral in the district. The other sulfides
and scheelite were deposited in an epithermal environment, and fractures were the major
deposition control. The deposition of Au (only observed as native Au in one sample from the
district) appears to have been dependent upon a wide range of conditions. At least part of the
deposition of metal- bearing minerals appears to have been a meteoric water - dominant event
during the Eocene.
Preliminary Fluid Inclusion Data 1
Inclusions from fluids that circulated in deep plutonic or metamorphic environments and
from fluids of shallow environments are both present in the district. Deciphering the complex
history of the Yellow Pine district requires more detailed fluid inclusion work, but a
preliminary survey reveals some characteristics of the quartz within the district characteristic
of the two environments. The deep- environment quartz is characterized by (1) ubiquitous,
wispy textures of secondary inclusions defining millions of healed microfractures which cause
the quartz to be cloudy or milky in appearance, (2) the presence of several one phase aqueous
inclusions, concentrations of inclusions with inconsistent liquid to vapor volumetric ratios at
grain boundaries, (3) the presence of healed microfractures with inclusions oriented
perpendicular to planes, and (4) the presence of gases (CO, ?,CH2 ?, and N,,?) under pressure
within many inclusions. Sphalerite is sparse in quartz from a deep environment.
Quartz veins containing inclusions typical of a shallow depositional environment cross-
cut the milky quartz veins. The shallow quartz characteristically has cockscomb,
cryptocrystalline, or chalcedonic texture. Inclusions in cryptocrystalline and chalcedonic quartz
are characteristically smaller than 2 mm while those in open- space - filling quartz are
593
COOKRO. SILBERMAN. BERGER
characteristically liquid -rich, two- phase, primary aqueous inclusions. The shallow quartz is the
dominant variety of quartz deposited during mineralization. The cryptocrystalline and
chalcedonic quartz in some samples from the Yellow Pine Mine have inclusions that are too
small to study; this is common with quartz thought to have formed at temperatures less than
2001 C. Scheelite, stibnite, and arsenopyrite are included within the shallow quartz.
A third type of quartz is clear and is always formed around the margins of the deep
quartz. The deep quartz, where surrounded by clear quartz, is rounded, suggesting that clear
quartz formed at the expense of deep quartz. Epithermal quartz cuts across and grades into
the margins of the clear quartz, which is also considered to be of shallow origin. Scheelite is
also-present within the clear quartz. A possible mechanism for the formation of the cleat
quartz could have been the local buildup of pressure in areas along faults that were completely
sealed with silica and formed a closed system. The margins of the primary quartz would .
recrystallize when the pressure was released by fault movement (Fournier, 1986).
The results of our quartz petrographic and fluid - inclusion survey suggest that Au
deposition occurred over a wide range of conditions. The stibnite and Scheelite depositional
event was more constrained in regional extent than the gold depositional event. These
minerals are concentrated in zones of open brecciation, and fluid- inclusion morphology
suggests a low temperature (< 200° C) environment for both of these minerals.
Geochemistry
A total of 64 rock samples were analyzed from 21 different mines, prospects, and
nonmineralized background locations within the Yellow Pine mining district. Sample
locations and descriptions are shown on Figure 4.
Sample preparation and analytical procedures
Samples weighing 2 -10 kg were collected and crushed with a mechanical jaw crusher and
then pulverized to less than 200 mesh ("0.15 mm) before splitting for analyses. Analyses
consisted of semiquantitative emission D.C. arc spectrography (E -spec) for 31 elements using
a method described by Grimes and Maranzino (1968). Table 3 lists the limits of determination
for those elements. Wet chemical analyses supplemented the E -spec results for certain
elements in which the determination limits were too high or for elements that were not
determinable by E -spec. Elements analyzed by the wet methods included Au, As, Sb, Hg, Zn,
T1, Te, and F. A summary of the methods used and their limits of determination and their
relative standard deviations are listed in Table 4. Analytical results are tabulated in Appendix
B and, for selected elements, are shown as bar graphs in Figures 9 -16.
Distribution of trace elements at Yellow Pine
Cooper (1951) and Lasmanis (1981) both suggest that ore deposits in the Yellow Pine
district are zoned according to depth at the time of mineralization. Lasmanis (1981) tabulated
the present elevations and the principal metals produced from mines and prospects. Hg
deposits and concentrations (Fig. 8a) occur at high elevations, Au at intermediate elevations,
(Fig. 9b) and Ag -Sb -W at the lowest elevations. Analytical results are tabulated with
elevations of the samples in Appendix B and arranged in bar graphs in order of elevation
(Figs. 9 -16). Patterns on the bar graphs represent different lithologies. The key to the
patterns is on Fig. 9. Because the sample suite at each location was too small for meaningful
statistical analysis and quite a variety of lithologies are represented at each location, we have
summarized the results element by element, as follows.
594
YELLOW PINE MINING DISTRICT
Gold
Of all the mines and prospects sampled, the highest gold content (30 ppm, Fig. 10) was
found in a quartz vein cutting silicified and sericitically altered granitic rock in the Au zone of
the eastern part of the Yellow Pine pit. Gold content is highest in this zone, although both
the Sb and W zones also have high Au contents (0.5 -3.3 ppm). Distribution of Au in our
samples from the West End Mine was erratic. Samples from the lower (main) pit at 2073 m
(6,800 ft) generally contain between 0.3 and 1.7 ppm Au in oxidized schist and quartzite ore,
Table 3
Limits of determination for the spectrographic analysis of rock based on a 10 mg. sample
Element Lower Determination Limit Upper Determination Limit
Percent
Iron (Fe)
0.05 20
Magnesium (Mg)
0.02 10
Calcium (Ca)
0.05 20
Titanium (Ti)
0.002 1
10,000
Parts per million
Manganese (Mn)
10
5,000
Silver (Ag)
0.5
5,000
Arsenic (As)
200
10,000
Gold (Au)
10
500
Boron (B)
10
2,000
Barium (Ba)
20
5,000
Beryllium (Be)
1
1,000
Bismuth (Bi)
10
1,000
Cadmium (Cd)
20
500
Cobalt (Co)
5
2,000
Chromium (Cr)
10
5,000
Copper (Cu) '
5
20,000
Lanthanum (La)
20
1,000
Molybdenum (Mo)
5
2,000
Niobium (Nb)
20
2,000
Nickel (Ni)
5
5,000
Lead (Pb)
10
20,000
Antimony (Sb)
100
10,000
Scandium (Sc)
5
100
Tin (Sn) ,
10
1,000
Strontium �(Sr)
100
5,000
Vanadium (V)
10
10,000
Tungsten (W)
50
10,000
Yttrium (Y)
10
2,000
Zinc (Zn)
200
10,000
Zirconium (Zr)
10
1,000
Thorium (Th)
100
2,000
595
COOKRO. SILBERMAN. BERGER
although one sample from a clay seam contained a high value of 6 ppm. Samples from the
upper pit at 2170 m (7,120 fry generally had lower Au content, only 0.1 -0.3 ppm. Samples
from the Fern Mine, at 2438 m (8,000 ft) had low Au values, in the range of 0.1 ppm or less,
except one sample of argillic gouge which contained 1.5 ppm Au, collected beneath a jasperoid
outcrop. A sample from the DMEA prospect at 2024 m (6,640 ft) contained 1.6 ppm Au and
most of the gold - related metals.
Au concentration (Fig. 9b) generally decreases with increasing elevation in the Au zone
of -.he Yellow Pine pit. It is still quite high in the W and Sb zones of the mine. Cooper (195 1)
stated that gold concentration was relatively low in the Sb and W ore bodies, which was true
from an economic standpoint at that time, but the Au contents of the whole Yellow Pine
Mine system are strongly anomalous.
Background Au contents in most samples of nonmineralized rocks were below 0.05 ppm,
the lower limit of determination. Exceptions include a sample of fault gouge from near the
West End Mine which contained 1.3 ppm Au, and some samples collected along the access
Table 4
Chemical methods used
AA = atomic absorption; Inst. = instrumental;
SI = specific ion; S = spectrophotometry.
Element
Method
Determination limit
(micrograms /gram
or ppm)
% RSD
Reference
Gold (Au)
AA
0.05
9.3 -42.5
O'Leary and Meier
Mercury (Hg)
Inst.
0.02
8.2 -30.4
Modifications of McNerney
and others (1972) and
Vaughn and McCarthy (1964).
Antimony (Sb)
AA
2
1.1 -10.0
Modifications of Viets (1978).
Arsenic (As)
AA
5
1.6 - 6.4
do.
Zinc (Zn)
AA
5
0.9- 3.4
do.
Thallium (TI)
AA
0?
2.4 -14.4
Hubert and Lakin (1973).
Fluorine (F)
SI
100
.98- 5.51
Hopkins (1977)
Tellurium (Te)
AA
0.005
2.8 -15.6
Chao and others (1978).
RSD = Relative Standard Deviation
Emmissions spec. by M. S. Erickson and E. F. Cooley
Wet chernistry under the direction of R. M. O'Leary
596
YELLOWY% PINE MINING DISTRICT
y`
-101 it
4414 k
le
Ar
K ,
JO
s s ti �► .
Ar
Of
OPA
Figure 8a and b. Scheelite in altered granitic rock of the Idaho Batholith showing several stages of
brecciation and quartz + scheelite veining. Sample is from the Golden Gate Mine. a: altered granitic rock in
ordinary light, bar is 1 cm., a: sample in ultraviolet light showing fluorescing scheelite.
road, also near the West End Mine, which contained 0.05 to 0.15 ppm (020 in silicified
limestone from above the West End Mine). All other samples from along the access road had
Au contents that were detectable but below the loner limit of detection. Elsewhere, Au
content of samples was generally not detectable. To better interpret the background
distribution of Au, lower determination limits would be necessary. Background,
nonmineralized samples from high elevations near the Fern Mine did not contain detectable
Au, with the single exception of a Fe -oxide pod in limestone; the gold content of this sample
was probably related to the previous sulfide content of the pod. The nonmineralized granite
597
Hg AA
0.01 LD
L---f-f
2438 M j
2170 M
0.1
M11 I
) FERN MINE
2073 M� (6800') WEST END PIT
(MAIN)
2024 M
00
1902
18•0 M ff 3 w =V=
1890 M
ZONE)
10
U
�0�0
YA
PPM
W E SPEC
10 LD 100
L 1000 10,000
'U'jo
2438�(8�000') FERN M�INE �
N ZA (N D))
10 0 El
• El Fa
E3
ku4VU-1 YELLOW PINE PIT (Sb ZONE) (ND)
M mom
KEY To BAR GRAPtj PATTERNS
.. .
... ... . ..
1890 M (6200') YELLOW PINE PIT (Sb ZONE) ..... r,' 13 EM EM EM Granite clay goilge
EMSchist/Quartzite Skarn
Jasperoid/Carbonate
Quartz vein Tertiary dike
Figure 9a and b. liar graphs showing (a) Hg and (b) W contents at selected sample locations. AA� atomic absorption, E sPec= emissions spec-, 1-1)= limit
ND� [lot detected.
11 of detecti(i
O
O
O
Pj
As ESPEC
LD 10 100
2438 M (80tOO�')F ERN MINNE L
2170 M (7120') WEST END PIT (UPPER)
2073 M (6800) WEST END PIT
PPM
1000 10,000
J1L1._1 1 1 1 1 1 1 1 I I I I I I I l i
1 • . / 1
Nr }YiA:�!. YAM.• �tY�l iV�i!G!•�iC�f�rli!.1.�.�.A.�.r� .. . n •.•nyr � ...tl. •. •y !� r�•py � 1
1 .. R... aA-!• A!•. l: f.. iY'•.• 1!• 1Y1!•! ITi!•i!�aT•!!•y�.'I.T.•RI:f•)!1
'1 11
_YE LOW •
l ��•,rrrJ:r��';f. {/r�j',••'�' 1�,j .•�v'r.r {r r¢f•rvr•.r...vr. rr r...,.•. yv• .yv .y .••••
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2438 M (8000) FERN MINE
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2073 M (6800'1 WEST END PIT (LOWER)
13 M h
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b
2024 M (6640')DMEA 7
1902 M ;(6200') ONANZA
z
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00
1890 M LLOW PINE PIT (W ZONE) y
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Patterns are explained in Fig and (b) Au contents at selected sample locations. E spec = emissions spec., AA= atomic absorption; LD= limit of detection.
COOKRO, SILBERMAN, BERGER
sample taken at the entrance to the Yellow Pine pit did have 0.1 ppm Au, but the analysis was
not reproducible.
On the basis of the current sample suite, no intrinsic pre - concentration of Au appears to
exist in rocks of the region, although barely detectable to low -level concentrations are p resent
in several lithologies along the access road near the West End Mine (particularly in quartzite
and schist, which are the most favorable host lithologies, and in amphibolite and felsic dikes).
Although we do not have background ( nonmineralized) samples from around the Yellow Pine
Mine, we suggest the low -level concentrations may be a primary halo around the West End
.Mine rather than a regional elevation in Au background levels.
Tungsten _
Tungsten analyses (Fig. 9b) in this study were done by E -spec, which has a limit of
determination of 50 ppm; therefore, determining the distribution of low -level W in the
samples was not possible. Cooper (1951) indicates that W mineralization followed Au
mineralization, and Lewis (1984) agrees. The present study indicates that W was deposited
during several stages in the regional paragenesis, in a variety of environments, possibly
including trace scheelite deposited by currently active thermal springs (see earlier discussion).
Significant concentrations of W were found in samples from only three areas: (1) in
altered, brecciated granitic rock from the W zone of the Yellow Pine Mine, where
concentrations greater than 10,000 ppm 0 %) were detected; (2) in altered, brecciated granitic
rock from the DMEA prospect, where 1,000 ppm W were detected; and (3) in jasperoids and
manganese- and iron -oxide fault gouge from the Fern Mine, where concentrations in the
range 200 -1,000 ppm were detected.
Tungsten was not detected (absent at 50 ppm or above) in any of the nonmineralized
background samples including talc- silicates, with the exception of a sample of iron -oxide fault
gouge from along the access road near the West End Mine, which contained 100 ppm.
Antimony
Antimony content (Fig. l la) is highest within the Sb and W zones of the Yellow Pine
Mine, from which most samples contained 10,000 ppm (170. It is considerably lower, but still
anomalous, in the Au zone (up to 100 ppm). The brecciated granite at the Bonanza prospect
has 10,000 ppm Sb. The distribution of Sb in samples collected elsewhere in the district does
not show any correlation with elevation. Moderate values (>100 ppm) are encountered at the
DMEA prospect and occur erratically at the West End Mine, but Sb contents in most samples
from those two localities are below 200 ppm. Antimony contents of the Au zone of the
Yellow Pine Mine and of the West End Mine are similar. Sb content of jasperoids and iron -
oxide fault gouge at the Fern Mine ranges between 50 and >10,000 ppm. The concentration
of Sb is highest at the lowest exposed elevations in the Yellow Pine Mine, Sb and W zones
and at the hig est elevations at the Fern Mine. However, very high Sb content is not
associated with Au mineralization in the samples from either the Yellow Pine or West End
deposits. It is interesting to note that the very high Sb content at the Bonanza prospect
(10,000 ppm) is not associated with any Au, and at the DMEA prospect, where Au is present,
content of As and many other metals are high, whereas Sb content is not.
Antimony concentration in non- mineralized, background samples collected throughout
the district is strongly elevated relative to crustal average for a variety of lithologies, but no
patterns related to elevation are obvious. Samples showing strong oxidation tend to have the
highest Sb contents. These samples previously contained sulfcles.
Arsenic
Arsenic concentration (Fig. 10a) in samples from the Au and Sb zones of the Yellow
Pine Mine are consistently high ( >10,000 ppm) but erratic. The W zone also has erratically
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COOKRO, SILBERMAN BERCER
high As but the maximum values are lower than in the o
greater than 10,000 Cher two zones. Arsenic content of
rock, where it is associated 0 pp also present ata the D anomalous A
(but not much Sb). It is generally high (u to 1 S00 prospect in brecciared, altered granitic
concentrations of Au and ocher metals
The jasperoids and gouge of the Fern Mine contain 1500 to both OOppirs at the West End Mine.
indicated a close association of As with Au and indicated that areas with
pyrite tended to have good Au grades. This stud ppm As. Cooper (1951)
y corroborates the association of Au and with
arsenopyrice and pyrite. A11 samples containing 1
Ib and b show that Au has a more consistent association with As than w'
g ppm Au have >1w with ppm gs. Figures
llb). irh Sb
In unmineralized rocks Figs. l0a and
average for the lithologies sampled content erratic but commonl
determination limit. Arsenic concentrations in excess of 10 y strongly above crustal
P occurs in all samples where Au was above
of unmineralized lithologies from high elevations near the Fern Mine. I
erratic along the access road near the W ppm were detected in all samples
of the Yellow Pine Mine is strongly anomalous in As (28 m is distribution is more
West End Mine. Altered granitic rock from the margin
granite (1.5 -1.9 ppm) Pp m) relative to crustal average for
Mercury
Mercury content (Fig. 9) does not decrease at lower elevations in the min
Mercury content is highest in the jasperoids and gouge of the Fern Mine >
is strongly anomalous in samples from most of the rest of the district including
mineralized zones.
nonmineralized samples. Few samples had less than 0.1 ( 10,000 ppm), but
average for the lithologies. Mercury in samples from lower el o strongly most of the
ppm, which is strongly above crustal
zone of the Yellow Pine Mine and at the Bonanza prospect. In both places, the
evations is highest in the W
exceed 10 pprn (the upper limit of determination). The Sb and Au zones of th
Mine have general] lower highest values
y Hg contents but contents of up to 1.8 e fellow Pine
from both West End Mine pits are strongly anomalous, containing up present. Samples
Samples of the brecciared granite at the DMEA prospect also car
In the nonmineralized samples H g P to 4.6 ppm Hg•
Hg content tends to be higher n the samples at
high elevations, but the distribution is spotty.
and a felsic dike, taken along the access road near the Wes End1Mineaarry > n ppm. olice
Thallium carry ZO ppm.
Thallium concentration (Fig. 12a) is highest (2.4 -43
ppm) at the Fern Mine, but it is at
or below crustal average at most of the other mineralized areas. It is most consistently
1-2 ppm, in the Au and Sb zones of the Yellow Pine Mine and generally less than this high, in the
W zone. The h- '' concentration in a
ppm at the DMEA prospect, where it is barely mineralized
above crusstaleaveran at high nice. elevation is 3.4
was not detected (limit 0.2 ppm) in most unmineralized samples, even chose with
age for granite. Thallium
content.
high Hg
Silver
Silver ( Fig. 1 1 b) favors Lower elevations in the study area, but its distribution irregular. In the Yellow Pine Mine Ag is highest in the W zone (one sample
ppm), but high m both the W and Sb zones 1 -st uai is very
Silver content is much lower (>0.5-7 ( PPm) and more consistent ino[hetSb zon00
is more common in the lower West End ppm) it than Au
n he u High A
from the DMEA prospect carried 10 P g g content (up to 200 ppm)
Peer pit (up to 3 PPm)• A sample
Silver was not detected in samples from the Fern Mine, which is at high PPm g and high concentrations of As, Au, Sb, and Hg.
samples from the Bonanza prospect, which is at a lower elevation.
g elevation, nor in
602
0
TI AA PPM
LD Te AA
0.1 1.0 10 LD Zn E SPEC
L1L r r rlrrrlr r r rrr1100 0.01 0.1 LD
2438 M (8000') FERN MINE 1.0 10 1.0
2438 M ) 10 100 1000
(B 10 FERN MINE
2438 M (8000') FERN MINE
2170 M (7120') WEST END PIT (UPPER) "'
2170 M (7120') WEST END PIT (UPPERI 2170 M
(71207 WEST END PIT (UPPER)
2073 M (6800') WEST END PIT (MAIN) _-
2073 M (6800') WEST END PIT (MAIN) 2073 M
(6800') WEST END PIT (MAIN) N
N
2024 M (6640)DMEA - -
2024 M (66407DMEA b
1902 M (6240') BONANZA - 2024 M (6640')DMEA Z
_ _
1902 M (62407 BONANZA
1890 M (6200') YELLOW PINE PIT (Au ZONE) - 1902 M (6240') BONANZA
1 Z
890 M (6200') YELLOW PINE PIT (Au ZONE Z
1 (6200') YELLOW PINE PIT (Au ZONE) p
1890 M
1890 M (6200') YELLOW PINE PIT (W ZONE) 1890 M
� 6200') YELLOW PINE PIT (W ZONE
(6200' ) PIT YELLOW PINE n
1890 M (W ZONE) y
1890 M (62001 YELL PINE PIT (Sb ZONE)
f W)W
18gp M (6200') YELLOW PINE PIT (Sb ZONE ) (62001) YELLOW PI
1890 M NE PIT (Sb ZONE)
Figure 12a, b, and c. Bar graphs shuwink contents at selected sar _ _ 1
detection. Patterns are explained in h (b) Tc, and (c) Zn cont
iK. 9. nple locations. AA= atomic absorption, E s ec=
p emissions spec,, 1,1) =lunit of
COOKRO, SILBERMAN, BERGER
Only four samples from the nonmineralized sample suite had Ag contents above the
limit of detection of 0.5 ppm; they ranged from 1 -5 ppm. None of these four samples was
from high elevation; rather all were from near the access road.
Copper, lead, and zinc
The Yellow Pine district mineralization does not have a strong base metal component.
Copper (Fig. 13) is irregularly distributed in the district. The highest concentrations are in
carbonate units in the lower West End Mine (100 and 2,000 ppm) although those same
carbonate rocks are not good hosts for Au. Copper is present in concentrations as high as 200
- ppm in jasperoid samples from the Fern Mine and concentrations as high as 300 ppm -in the
Yellow Pine W zone. Copper contents are near crustal average for the samples from most
other locations, including the unmineralized samples. Lead (Fig. 13) is generally at low
concentration levels, only two samples contain more than 100 ppm, both from the Yellow
Pine Mine W and Sb zones. Zinc (Fig. 12c) concentration in most rocks is at or below crustal
averages, but the Fern Mine jasperoids have the highest concentrations (up to 110 ppm).
Tellurium
Although detectable concentrations are very spotty, high Te values (Fig. 12b) occur in the
altered granitic rocks of the Au, Sb, and W zones of the Yellow Pine Mine and the upper pit
of the West End Mine. The highest value we found was 5.6 ppm in a sample from the upper
pit of the West End Mine. Most of the Te is at low elevation in the Yellow Pine Mine. Nearly
all unmineralized samples contain less than the lower determination limit of 0.1 ppm Te.
Barium and Strontium
Barium content (Fig. 14b) of most samples is at or below crustal average concentrations
for the lithology. Barium contents of 500 to 1,000 ppm are common at both the Yellow Pine
Mine and the West End Mine. Barium content of a few jasperoid samples from the Fern Mine
are greater than 100 ppm (about average for carbonates), but the maximum is only 300 ppm.
Barium anomalies are common in some carbonate- hosted disseminated gold deposits, or the
jasperoids associated with them, but the range of values is large (Hill and others, 1986) and
fully encompasses the Ba contents at the Fern Mine. Barium content of unmineralized
samples is highest in the high - elevation samples collected near the Fern Mine where skarn,
marble, and schistose sandstone contain 500 ppm Ba, as opposed to the 50 to 300 ppm Ba
detected in the Fern jasperoids.
Strontium content (Fig. 14c) is highest in the W zone of the Yellow Pine Mine, and
somewhat lower in the lower pit of the West End Mine. Unaltered igneous rocks (granite
from the edge of Yellow Pine pit, felsic dikes from the access road) appear to be enriched in
Sr relative to crustal averages. The Au and Sb zones at the Yellow Pine Mine have little Sr in
comparison to the W zone ( the sample that contained 1,000 ppm Sr from the Sb zone is a late
dike, not part of the ore).
Manganese
Epithermal precious -metal systems frequently exhibit Mn haloes around the ore deposits
(Silberman and Berger, 1986; Berger and Silberman, 1986). Although detailed sampling has
not been done at Yellow Pine, the Mn contents (Fig. 15a) of samples from the Au and Sb
zones at Yellow Pine and the West End Mines are generally lower than those in the
unmineralized samples collected for background, parricularly along the access road. The high
Mn samples from the Au and Sb zones of the Yellow Pine Mine are from late dikes that cur
the altered granitic host rock. Manganese contents of samples from the lower pit at West End
are higher than those of samples from the upper pit. The highest Mn contents occur in skarn
and marble, but these are not much greater than crustal average for those lithologies. The Mn
604
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1.0 • 10 100 • Sr E SPEC
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2438 M •• 1000
:1.1
2438 M (8000) FERN MINE
2170 1 • PIT (UPPER) 1 1 PIT (UPPER)
2170 1 • PIT (UPPER)
1 •:1•
• 2073 M
(68001
WEST END -
'• 1 •:1• • PIT rr•,, °
•
' �' rJ�' Y `i�yl..•!{ASSyaSla'iaY...!h�Y.. •':b:9'iSti
1 24 M (6640')DMEA YJ•l.;r.•;•} tr.:�Jy:•:•r8•:riFfeY
1 •••1 •
1902 M (62409
err • ...� ,F'�s".�J!. '•�' 1 (6640')DMEA
H.1WMM1�'.•'i�.'4�'1M11+ •J'lf.: 1 1 • ' • : • , •
• Va54! ?.r?iS•Yd�kby4kY4•.X•y 1902 • • BONANZA
• '1 • •1 YELLOW
ZONE) '1 • •• YELLOW
� :v 1 •
YM1S:i:•i�! %iia' •�.a e��.a ., • .•�'J� ��{, y{, , „ii{i • • �i {..y.,.�rii SJr�•
:91 M (6200') YELL• ZONE)
01 YELLOW PINE PIT (W • ''r • ry , 1 . e'rY.,.....��i�.. rig rr 1890 M (62001 YELLOW
•Y'•;r;�'�''d � •V • • f •, •'i ih/ •i'• ryti��S. • '•4KY7dliiriy,�!i•� ' • • , i,�,A•�•,,.Y �I/ ZONE
1890 M [6200') YELLOW PINE PIT :!a } }J' h �• {�;,• • �f'�':�I.A:tiY.T.'31. i , .•r y}� l�i j,i•�'1
• • NE) 162001 • :. .'{: YT:: S•}: rdS ::rfr }A +r:::tirr{::•:rff.:frffA
t •. 1890 M, ,.,...,.........,� • • :: 1
....flJi�htiSSK!►� • {'',•: ^: {4h, ,,•' % {4hY.Y. {y.;r
YELLOW PINE PIT fSb ZONE)
figure b, and c. Rat graphs showing (a) B, (b) Ba, and (c) Sr contents at selected sample locations. E Spec= -
explained d in , Fig• ).
P stops, spec LL>- limit of detection. Patterns are
YELLOW PINE MINING DISTRICT
of those lithologies lack Cr. Boron contents (Fig. Zia) of samples from the Au zone at Yellow
Pine and the lower pit at West End are slightly higher than those in samples from other
mineralized areas, although the ranges for these two groups overlap. The B contents (Fig.
14a) of the jasperoids at Fern are generally lower than those of other mineralized zones.
White (1981) suggested that B concentrations occur in the upper parts of many geothermal
systems that host precious metals. This is not the case for the Fern Mine, although many of
the other epithermal trace elements occur in abundance.
Summary of the Geochemistry
There is some indication of metal zoning by elevation in the Yellow Pine district, but it is
not as simple as has been suggested in the earlier studies. The high background values for Hg,
As, and Sb throughout the district certainly suggest that the entire area was subjected to
hydrothermal activity. This activity most likely was fracture controlled and produced greater
concentration of these and other metals in the zones where fractures, and breccia are
well - developed.
1890 M
1890 M
1890 M
YELLOW PINE PIT (Au ZONE)
00') YELLOW PINE PIT W ZONE)
PPM
Cr E SPEC
10,000 1.0 LD 10 100 1000
11111 1 1 . . _....... _
2438 M (8000') FERN MINE
2170 M (7120') WEST END PIT (UPPER)
2073 M1(68000') WEST END PIT (MAIN)
2024 M (6640')DMEA
1902 M (6240') BC'JANZA
1890 M (6200') YELLOW PINE PIT (Au ZONE)
(6200') YELLOW PINE PIT (W ZONE)
PINE PIT (Sb ZONE) 1890 M (6200') YELLOW PINE PIT (Sb ZONE)
Figure 15a and b. Bar graphs showing (a) Mn and (b) Cr contents at selected sample locations. E
spec = emissions spec.. I.D =limit of detection. Patterns are explained in Fig. 9.
607
COOKRO, SILBERMAN, BERGER
Summary plots for some of the elements that either suggest a zoning pattern by
elevation or have economic significance are in Figs. 9 -16. Gold does appear to be more
concentrated at lower elevations. Only one sample containing more than 1 ppm Au was found
above 2073 m (6,800 ft) in the current sample set of mineralized rocks. Alternatively, Sb
occurs in very high concentrations at both high and low elevations. Mercury tends to be
concentrated near the upper elevations of the system, but almost all samples from the Yellow
Pine district are strongly enriched in that element. Thallium is present in abundance only at
high elevations. Arsenic tends to be concentrated at moderate to low elevations, although a
single sample from the Fern Mine contained >10,000 ppm. Zn, while very 'irregularly
distFibuted, tends to be more consistently present at high elevations (in the Fern jasperoids�.
Fluorine, not discussed earlier, is present in strongly anomalous concentrations at moderate -to
high - elevations, rather than at low elevations. For the unmineralized samples, only Hg
appears to show a slightly elevated content at higher elevations.
La E SPEC
10 L 100 1000
2438 M L20001 FERN MINE
2170 M (7120') WEST END PIT (UPPER)
2073 M (6800') WEST END PIT (MAIN)
2024 M I (6640')DMEA
1902M[(6240') BONANZA
PPM
Co E SPEC
10.000 1.0 LD 10
1890 M (6200') YELLOW PINE PIT (Au ZONE)
1890 M (6200') YELLOW PINE PIT (W ZONE)
1890 M (6200') YELLOW PINE PIT (Sb ZONE)
2438 M
100 1000
RN MINE
2170 M (71201 WEST END PIT (UPPER)
2073 M (6800') WEST END PIT (MAIN)
2024 M (6640')DMEA
1902 M (6240') BONANZA
1890 M (6200') YELLOW PINE PIT (Au ZONE)
1890 M (62001 YELLOW PINE PIT (W ZONE) (ND)
1890 M 1 (62001 YELLOW PINE PIT (Sb ZONE)
Figure 16a and b. Bar graphs showing (a) La and (b) Co content from selected sample locations. E
spec= emissions spec.. LD =limit of detection. Patterns are explained in Fig. 9.
608
YELLOW PINE MINING DISTRICT
Conclusions
The paragenesis of Au- Ag -W -Sb mineralization in the Yellow Pine mining district is
complex. The analytical techniques yielded results that appeared contradictory at first glance.
Petrographic and geochemical data show that fractures are the major control on the
deposition of metals. 40Ar /39Ar and K -Ar age determinations suggest that at least two
different alteration events, rather widely spaced in rime, late Cretaceous and Eocene. Oxygen
isotope and deuterium/ hydrogen isotopic ratio data suggest that fluids of deep origin or
evolution and meteoric dominant origin were active in mineralization. A fluid inclusion survey
suggests that epithermal processes were dominant in the development of the sulfide - scheelite
concentrations, and the sulfide - scheelite deposition probably occurred at temperatures less
than 200 °C ( Cookro and Silberman, 1987; Cookro, unpub. data 1987). The trace -metal
assemblage, Au, Ag, As, Sb, Hg, and W, is characteristic of epithermal precious -metal deposits
(Berger and Eimon, 1983), but vertical trace -metal zoning throughout the district is more
complex than predicted by epithermal trace -metal zoning models or than suggested by
previous authors.
The primary reason zoning in the district differs from that predicted by previous models is
that the silica -rich fluids, which transported and deposited sulfide - scheelite concentrations,
were convecting along widely - altered, north - trending regional faults (Fig. 17a) and those
faults continued to move throughout the depositional history. Mineralization is concentrated
along these north - trending faults and their associated easterly trending deflections and splays
where movement (or an easterly torque) caused more open brecciation. Late Cretaceous and
Eocene plutons coalesced at depth along the active faults. When meteoric fluids (Fig. 16b)
collected and flowed in along the faults they were heated at depth, causing them to circulate
toward the surface (Fig. 16c). Since fluid flow to the surface is greatest in the zones of more
open brecciation, concentrated metal deposition occurred in those zones. Movement along the
faults disturbed an "ideal" zoning pattern which might have developed in a more stable
system. Each displacement event changed the local pressure - temperature regime and the
pattern of flow along the faults, causing a series of overprinting events.
Gold deposition in the district was not specifically controlled by one process. Gold is
associated with pyrite, arsenopyrite and stibnite; it also occurs as free gold. The gold - related
sulfides, in albite and adularia veins which contain arsenopyrite and pyrite, could be either
deep metamorphic or epithermal; textural relationships are not clear. Adularia veining, which
is commonly associated with near - surface low- temperature conditions, began while
albitization was still occurring. Some albite veins cross -cut adularia veins, but the more
common relationship is late adularia veins cross - cutting albite veins. Both albite and adularia
veins occasionally contain flakes of sericite. Sericite from a quartz vein at Yellow Pine was
dated by Snee (unpub. data, 1986) as Late Cretaceous. Gold - related sulfides also occur in
epithermal quartz, which contain pyrite, arsenopyrite and stibnite. Hydrothermal calcite and
Mn and Fe oxides are also a part of the epithermal phase in the Yellow Pine district. Finally,
free gold is present in vugs with euhedral quartz in the district and in oxidized ore at the
West End Mine. Lasmanis (1981) reports gold in the oxidized ore to be along fractures and
disseminated throughout.
Less is known about silver in the district. Cooper (1951) reports it most closely associated
with stibnite, whereas this study shows it is erratically associated with antimony and arsenic.
Lewis (1984) identified miargyrite with the stibnite at the Yellow Pine Mine. Silver is also
evident in some of the oxidized zones where stibnite is absent. A few of our unmineralized
samples of granodiorite carry traces of silver. On the basis of present evidence, we conclude
char the silver probably was deposited only by epithermal processes.
609
COOKRO, SILBERMAN, BERGER
A
Figure 17a. Generalized block diagram of the regional geology in the western part of the Challis l ox2°
quadrangle. The right - lateral faults have a wide zone of alteration along them. A =Idaho Batholith, B= Terriary
volcanic rocks of the Thunder Mtn Caldron Complex, C= metamorphic inclusions within the batholith, D =late
phases ( ?) of the Idaho Batholith.
l
C
Figure 17b and c. Generalized block diagrams of the geology in the Yellow Pine district. Rock units A
through D are explained on Fig. 17a; rock unit E =small Tertiary plutons ( ?), suggested by the presence of
Tertiary plutons shown on Fig. 3 in a black pattern. These granitic plutons crop out at the surface and are on
strike with the NE- trending regional faults. They are north of the district but are evidence of what could be
present at depth in the district, b= Surface and ground waters collect along the north - trending faults and
convect upwards upon heating at depth. c =The zones of highest fluid flow of upward- moving heated fluids
are those areas opened by east - trending secondary faults or where the main fault splays to the east (as
happened at the Yellow Pine Mine where the fault passes through a large block of metamorphic rock).
610
YELLOW PINE MINING DISTRICT
All of the tungsten within the deposits described in this paper is closely associate
quartz with textures characteristic of a shallow, is
skarns within the district which contain scheelite are another matter and d with
low-temperature environment. Tungsten
this environment. Tungsten may have been leached from some of the skarns, carrie
rich fluids, and redeposited in the epirhermal environment at the Yellow are not related to
and Quartz Creek Mines. The scheelite at these mines a rat always related d by silica -
and at the Yellow Pine Mine was deposited very close in time a' Pine, Golden veins,
ed to lace quartz veins,
scheelite- stibnite- bearing quartz veins at the mine. There is also latent phase of there are
deposition (Cookro, unpub. data 1987, and Petersen, 1984) which consists of tin
scheelite grains on Mn oxides. s scheelite
Stibnite, which no longer is a economic ore mineral, is the result of the Y al phase
e
of mineralization. It is closely associated with scheelite at the Yellow Pine Minermal phase
found in minor quantities at other mines in the district. A favorable site f
replacement in meta- argillire occurs at the Yellow Pine Mine, where the only
Meadow Creek fault warps over to the east massive stibnite replaced these stibnite
he north - trending
scheelite replaced crystalline, hydrothermal calcite in the matrix of breccias.hese rocks, while
Mercury, as cinnabar, occurs in trace quantities throughout the district. It is considered
have been deposited during the epirhermal process of mineralization because it is f
open pockets and in jasperoids. A possible very late stage of hydrothermal activit ma to
included the H ound in
Hg mineralization at the Fern Mine, which affected rocks at the highest
presently exposed elevation of our sampling. Y Y have
shallow manifestation of the epithermalphase lf mine aliozation. Fern Mine could also be a
Sphalerite, a trace mineral throughout the district, is included in dee
metamorphic quartz and is probably related to the Late Cretaceous pluton Mul however there
ism
is sphalerite veining in the district at the Quartz Creek Mine and the P plutonic or
are associated with clear quartz typical of the epithermal environment rather than the kind of
e Train claims that
quartz of the metamorphic event. At the Quartz Creek Mine sphalerite concentrations occurs
below the level of scheelite concentrations.
There are probably several genetic models which can be used to explain the spatial
relationships of mineralization- alteration and the isotopic and geochemical data. The m
we feel that best explains the data involves ac least two, and perhaps mot P 1
hydrothermal events. The first event of late Cretaceous age, was related to the odic
P e, epigenetic
of Idaho Batholith emplacement and resulted in the deposition of early sulfides gold
associated with albite and adularia veinin gold
completely understood, but faulting was an important factor. The original mineralization are not
deep origin, either magmatic or metamorphic, or had undergone high temperature isotopic
fluids were of
equilibration with meramorphic or batholithic rocks. Sericite, albite, and adularia are minerals
deposited during this early phase of mineralization.
In the Eocene, another stage of hydrothermal activity occurred, probably near the time of
volcanism which was of Challis age. Regionally, this activity produced large areas of meteoric-
in cells in the Cretaceous batholirhic rocks centered around Eocene intrusi
Gold- silver epirhermal deposits occur along the margins of these large cells (Criss and Taylor,
1983). Alternatively, the meteoric-hydrothermal cells may have been centered on ons.
ylo
Tertiary plutons localized along major faults, similar to the Tertiary small
northwest of the Yellow Pine district (Fig. 2). The epirhermal phase l in is at the surface,
district might be related to this later Eocene event. Tertiary dikes in the district are the only
he Yellow Pine
surface expression of the Eocene event, and our field evidence shows no correlation between
the shallow, low- temperature mineralization and the dikes. The hydrothermal activity
Yellow Pine resulted in the deposition of metal-bearing y at
scheelite, arsenopyrire, pyrite, and cinnabar are associ Gold,
distinctly epirhermal character. Isotopic ated with quart and quartz veins of
ratios indicate partial equilibration of earlier formed
611
COOKRO, SILBERAL4N, BERGER
alteration minerals (muscovite, sericite, adularia) and document the presence of a meteoric -
dominated fluid (by evidence of the D/H ratios in quartz fluid inclusions). The metals were
deposited along the faults and their associated splays; the process was most efficient in zones
of open brecciation or where the faults splay to the east. Alteration associated with this stage
of activity was sericitization, argillizarion, and silicification. Repeated episodes of brecciation
and mineralization along the shears, evidenced by the physical nature of the zones described
earlier, supports the low temperature interpretation. Because second phase of mineralization
took place at relatively low temperatures and we lack geochronological data on specific stages
of the mineralization, we cannot specify their precise timing or duration.
Acknowledgments
We would like to thank Bob Perkins, Bruce Harvey, and Mike Wolford of Superior
Mining Company for their help and support, and Karen Lund and Larry Snee of the U.S.
Geological Survey for their timely review of the paper and their helpful criticisms. Ben
Leonard (USGS) was very helpful in introducing us to the district and in providing historical
information, as well as providing his geologic map which was used in the compiled map (Fig.
4). A special thanks to Don White of the U. S. Geological Survey for our discussions on
Yellow Pine when he visited the area in the 1940's and now, and also his thoughtful
evaluation of our ideas. Our thanks also to Diane Jones and Loretta Ulibarri for editing the
paper and drafting figures, respectively, and to Yolanda Clausen for her clerical support in
producing the manuscript.
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COOKRO, SILBERAfAN, BERGER
Appendix A
Sample Descriptions
Tungsten Ore Zones Yellow Pine Pit 1890 m (6,200 ft)
M002: strongly brecciated and altered, silicified granitic rock: vuggy with euhedral quartz, sulfides and
scheelite common, calcite veins, stibnite, pyrite, arsenopyrite, sphalerite
M010: strongly brecciated and altered, silicified granitic rock: sulfides and scheelite common, cp'lcire veins,
stibnite, arsenopyrite, pyrite
M032: strongly brecciated and altered, silicified granitic rock: sulfides and scheelite common, calcite veins
stibnite, arsenopyrite, pyrite
M034: strongly brecciated and altered, silicified granitic rock: sulfides and scheelite common, calcite veins,
stibnite, arsenopyrite, pyrite
M111: strongly brecciated and altered, silicified and sericitized granitic rock: sulfides and scheelite
common, calcite veins, stibnite, arsenopyrire, pyrite
M113: strongly brecciated and altered, silicifed granitic rock: sulfides and scheelite common, secondary
calcite stibnite, arsenopyrite, pyrite
M130: strongly brecciated and altered, silicifed granitic rock: sulfides and scheelite common, secondary
calcite stibnite, arsenopyrite, pyrite
Yellow Pine Mine Au Zone 1890 in (6,200 ft)
Y1: silicified, sericitized granitic rock containing quartz veinlets: calcite veins, sulfides common,
arsenopyrite, pyrrhorite
YIA: quartz vein: sulfides common, calcite veins, sribnite, arsenopyrire pyrite, pyrrhotire, chalcopyrite
Y1B: quartz - pegmatite veins: some sericire alteration, sulfides present
Y1C: quartz larite dike: sulfides present
YID: sericitized pegmatite dike: sulfides common, secondary calcite, beryl, arsenopyrite
YIE: silicified, sericitized, granite with quartz veinlets: sulfides and scheelite present, arsenopyrite
Yellow Pine Mine Granodiorite 1890 m (6,200 ft)
Y2: sericitized granodiorite with pegmatite veins: some beryl and minor sulfides, some stibnite
Yellow Pine Mine Sb Zone 1890 in (6,200 ft)
Y3A: sericitized granitic rock with quartz veinlers: sulfides common, stibnite, arsenopyrite, pyrite
Y313: sericitized granitic rock: secondary calcite, sulfides present stibnite, magnetite, pyrrhotire
Y3C: sericitized, silicified granitic rock: sulfides present (disseminated) sribnite
Y313: sericirized, granitic rock: sulfides present, secondary calcite stibnite, pyrrhotite
Y4: diabase dike: secondary quartz veins cutting dike, arsenopyrite, pyrite, magnetite
616
YELLOW PINE MINING DISTRICT
West End Upper Pit 2170 m (7,120 ft)
YSA: quartzite
YSB: quartzite: limonite, muscovite, K- feldspar, chlorite and tourmaline are minor consti
present tuents, magnetite
YSC: quartz vein in quartzite: biotite, chlorite and magnetite are minor constituents, magnetite present
YSD: talc silicate skarn: diopside, calcite, quartz, actinolite and garnet
Y50 ): porphyritic rhyolire with quartz veinlets
Y5(2): porphyritic rhyolite with quartz veinlets: barite vein cross cutting dike
DMEA Prospect (also called SULFIDE #10) 2024 m (6,640 ft)
Y6: biotite felsite: calcite veins cut dike
Y6A: brecciated granitic rock: calcite and quartz veins, scheelite, arsenopyrire, stibnite, pyrite
Background Sampling, Access Road Near Yellow Pine Mine 2146 m (7,040 ft)
Y7: Mn- and Fe -rich fault gouge
Y7A: silicified quartzite: some vugs lined with euhedral quartz
Y7B: silicified quartzite: very fine grained unidentified opaque minerals
West End Mine, Main Pit 2073 m (6,800 ft)
Y8: schist: Mn- and Fe- oxides, graphite present
YBA: quartzite: Mn- and Fe- oxides, quartz, microcline, tourmaline, and pyrite minor constituents,
arsenopyrire and pyrite in cross - cutting veins
YBB: clay - pyrite- bearing fault gouge, in marble
Y8C: argillized dike: biotire and chlorite minor, very fine grained groundmass, fine grained opaques
YBD: silicified marble with quartz veins: stibnite, pyrrhorite,
Y8D(1): silicified marble with quartz veinlets: pyrrhorite, fine grained opaques
Background Samples
Y9: amphibolite: very fine grained, biotite present 2121 m (6,960 ft)
Y9A: Mn- and Fe -oxide -rich quartzite 2121 m (6,960 ft)
Y10: schist: tremolite, quartz, K- feldspar, tourmaline 2121 m (6,960 fr)
Y11: skarn: actinolite, quartz, serricirized plagioclase and sphene 2268 m (7,440ft)
Y12: silicified marble with quartz veins: some quartz veins are chalcedony, fine grained opaques 2218 m
(7, 280f t )
Y12A: Mn- and Fe -oxide -rich schist: quartz, biotire (chlorite),sillimanice 2218 m (7?80ft)
Y1 3A: skarn: quartz, diopside, tremolite- actinolite, phlogopite, plagioclase, epidore, zircon, fine - grained
unidentified opaques 207; in (6,800 ft)
617
Fern Mine 2438 m (8,000 ft) COOKRO. SILBERMAN. BERGER
Y14: jasperoid: chalcedony vugs lined with euhedral quartz, chlorite
stibnite, sphalerite ,zircon arsenopyrite, graphite,
Y14A: jasperoid: chalcedony, y vugs lined with euhedral quartz, sphalerite
Y14B: argillized, silicified limestone: punky texture
Y14C., chalcedonic fumerole lining: chalcedony, vugs lined with euhedral quartz ve com
YND: Mn- and Fe- rich -clay fault gouge rY mon, sphalerite
YNE: vuggy jasperoid
Y14F: silicified limestone: sheared, Mn- and Fe- oxides
Y14(1): jasperoid
Background Samples
Y15: epidote -rich skarn: epidote in bands, calcite, k- feldspar, phlogopite, tremolite, vesu
2
vianire, quartz
646 m (8,680')
Y16: marble with Mn- and Fe -oxide -rich pods: calcite, quartz, sphene fine grained opaque
m (8,760 ft)
minerals 2670
Y16A: marble 2670 m (8,760 ft)
Y17: schistose quartzite: Mn and Fe oxide stained, quartz, biotite,
sphalerite 2670 m (8,760 ft) i muscovite, sillimanre, chloriroid,
Y18: sugary - textured quartzite: chalcedony, vugs lined with euhedral quartz, zircon 2706 m (8,880 ft)
Y18A: black pyritic quartzite: abundant disseminated o a ues and oxides 2706 m
1'188: quartzite: vu p q (8,880 ft)
ggy, Fe and Mn oxides common 2706 m (8,880ft)
Y19: silicified dolomite: quartz veins, calcite /dolomite vein chalcedony veins 1877 m (6,160
ft)
Bonanza Prospect 1890 m (6,240 ft)
Y20: sericitized altered granitic rock: chalcedony veins, stibnite
Y20A: quartz vein stockwork in carbonate: magnetite, scheelite,fine- grained opaques comm
Background Samples 1890m (6,860 ft) on
Y21A: Silicified dolomite with quartz veins: calcite, quartz,
stockwork pattern muscovite, quartz veins and calcite veins in a
W
FIELD
NO.
M002
M010
M032
M034
M111
11113
M130
Y1
YlA
Y1B
Y1C
YID
YlE
Y2
Y3A
Y3B
Y3C
Y3D
Y4
Y5A
Y5B
Y5C
Y5D
Y5(1)
Y5(2)
Y6
Y6A
Y7
Y-/7A
Y7B
Y8
Y8A
Y8B
Y8C
Y8D
YBD( 1)
Y9
Y9A
Y10
Y11 7
Y12 7
Y12A 7
Y13 6
Y13A G
Y14 8
Y14A un
ELEV
6200
6200
6200
6200
6200
6200
6200
6200
6200
6200
6200
6200
6200
6200
6200
6200
6200
6200
6200
7120
7120
7120
7120
7120
7120
6640
6640
7040
7040 0
7040 p
6800
6800
6800
6800
6800 0.
6800 0.1
6960 0.
6960 0.0
6960 0.1
440
280
280
800
800 0.05
000 0.05
00 0 05
i ELLOW PINE MINING DISTRICT
Appendix B
Yellow Pine Quantitative Data
AU HG
0.5 1.4
1.9 0.5
3.3 G
1.1 1.5
0.25 0.7
1.4 1.7
0.85 G
5.6 0.14
30 1.8
1.7 0.62
0.15 1.4
0.25 0.62
2.8 1.1
0.1 0.02
2.1 0.72
0.8 0.32
0.85 0.5
0.6 0.9
0.1 0.26
0.1 0.3
0.3 3.1
0.2 3.6
0.05 0.06
0.1 1.4
0.2 0.48
0.05 0.82
1.6 3.7
1.3 4.8
.15 0.56
05 0.56
1.7 0.62
0.3 0.36
6 0.82
0.1 1.2
05 2.3
5 4.6 p
05 G
5 1.4
5 0.92
L 1.7
L 0.58
L 0.42
L 0.42
G N
G N
619
TE AS ZN SB TL F
3.5 410 25 G 0.15 i00
2.2 1200 25 G
0.9 300
7.5 580 40 G 0.35
0.25 400 15 G 1 ? 00
0.2 330 5 G 0.65 300
9 G 15 G 0.95' L
40 N G 0.05 L
5.7 G L 8 1.4 200
0.2 95 SL 46 1.1 200
0.2 1 L
5 L 8 2 2 200
0.3 G 5 12 1.6
0.7
.7 l0 5 28 2 0.2
70
1.6 G 10 4 0.2 2.2
1.8 190 160 2.2 2
0.4 90 40 G 2 1.4
1 G G 1.4 1.8
N 5 G 1.8 0.2
75 L 90 0.2 0.2
0.1 125 L 46 0.8 1.2
0.1 170 45 140 1.2
0.2 150 L 60 N 6
N L 5 N 0.6 200
.6
85
0.1 125 L 32 0.2 1
N 5 L 26 1 0.8
0.1 G L G 0.8 200
0.3 G 30 3. 100
0.1 l6 2.8
800
20 65 12 N L
N 35 10 18 N 100
0.4 680 55 82 1 900
0.1 110 5 54 0.2 100
0.7 450 L 20 1.4 500
0.1 5 10 22 1.2 800
N 5 L 8 N L
IV 75 L 190 N L
5 15 N 0.8 200
N 35 50 2 N
L
290 20 14 0.8 300
N 0.2 300
N L L 2) N L
N30 L 10 0.8 200
L L N N 300
10 5 6 N L
160 5 5-4 7.4 L
600 110 120 5.2
L
620
COOKRO,
SILBER1i4AN, BERGER
Appendix B
Yellow Pine
Quantitative Data (Continued)
FIELD
NO.
Y14B
ELEV
8000
AU
HG
TE
AS
ZN
SB
TL
Y14C
8000
0.1
L
G
G
N
290
35
I50
4
F
300
Y14D
8000
0.15
G
N
N
280
5
160
5
200
Y14E
8000
0.05
G
N
950
L
G
42
800
Y 14F
8000
1.5
650
40
G
�'2
L
.
Y14(1)
8000
N
G
43
N
G
45
G
200
Y15
8680
N
1.9
N
350
40
120
4.2
L
Y 16
8760
0.05
G
N
5
G
10
N
0.4
400
Y16A
8760
N
26
N
60
980
3
L
Y17
8760
N
1.7
N
10
L
N
N
L
Y 18
8880
N
1.8
N
10
5 5
N
0.6
200
Y 18A
8880
N
1.4
N
10
15
6
N
L
Y18B
8880
N
6.1
N
10
L
2
N
L
Y19
6160
1V
1 6
N
120
10
16
N
L
Y20
6240
N
G
0.8
10
L
6
N
L
Y20A
6240
N
G
N
15
25
960
0.6
300
Y21 A
6860
0.2
1
N
20
L
60
N
L
.4
45
10
8
0.2
400
Yellow Pine Semi - Quantitative Data
FIELD
NO.
M002
ELEV
6200
FE MG
CA
TI
MN
AG
AS
AU
M010
6200
0.5 3
0.7 2
3
0.05
3000
70
1000
N
B
50
BA
200
BE
M032
6200
0.7 0.05
3
0.1
0.3
0.05
2000
50
1500
N
100
1000
1
1.5
M034
6200
0.7 0.2
0.3
0.1
100
300
3
700
N
70
200
1
Mill
6200
0.3 0.5
1
0.1
2
500
N
100
500
1.5
M113
6200
1 0.15
0.1
0.05
200
20
500
N
100
700
1.5
M130
Z,I
6200
0.07 3
5
0.015
5000
1
1000
2000
700
N
100
S00
1.5
YlA
6200
6200
1 0.2
5 0.2
L
0.15
20
2
5000
N
10
50
200
30
500
1
Y 1 B
6200
0.5 0.15
0.05
L
0.15
0.03
20
7
7000
20
200
500
2
2
Y 1 C
6200
5 0.5
0.2
0.15
L
3000
1.5
500
N
100
500
2
YID
6200
1.5 0.5
0.7
0.07
300
N
N
N
20
500
5
Y l E
6200
5 0.5
0.?
0.5
200
1
5000
N
200
500
5
Y2
Y3A
6200
S 1.5
0.5
510
5
N
G
N
L
500
500
7
Y313
6200
6200
3 0.5
0.5 0.3
0.2
02
1>0
5
G
N
N
10
200
700
700
5
Z';r
6200
0.2 0.02
0?
L
0.02
�
0.0_
2 00
50
1000
L
50
300
5
1.5
YID
6200
5 0.7
0.5
0.03
L
300
20 500
N
20
200
1
Y4
6200
20 2
3
20 10000
L
200
700
2
YSA
7120
> 1
L
1
0.5
1000
1
200
N
10 1500
1.5
Y513
7120
2 0.1
0.05
0.2
100
100
2
300
N
500
1
Y5C
7120
1 0.05
L
0.03
50
1.5
1000
N
100
100
300
2
Y5D
7120
5 5
7
0.
3
1000
N
100
150
1
Y5(1)
7 2
1_0
0.5 0.02
L
0.01 1
1000
50
L
N
N
20 300 1.5
2
500
N
10 200
1
620
I
COOKRO. SILBERMAN, BERGER
Appendix B
FIELD fellow Pine Semi - Quantitative Data (Continued)
NO. ELEV BI CD CO
M034 62pp N CR CU LA MO NB
M111 62pp �' N 70 15 N NI PB SB
Mill 6200 N N N 150 15 30 N L 7 L 3000
M130 6200 62pp N N N 15 30 L N N 5 L 0
Y1 600 N 2p N 200 300 50 N L � 7 N 700
Y I A- 6200 N N N 30 15 50 L N L 300 G
YI 6200 N N L N 50 50 N 20 L 2p L
YIC 6200 N N N N 1p 50 N L L 20 200
YID 6200 N N L N 7 100 N ?L N 20 L
YIE 6200 N N 100 N 5 100 N 20 N 20 100
0 p
Y2 6200 N N 10 N 15 100 N 50 N L
Y3A 6200 N N 10 100 N 20 100
Y3B 6200 N N 10 N 10 200 U L 20 N
YK 6200 N N N N 3p 50 N 20 L 20 200
Y3D 6200 N N N N 15 50 N 20 L 100 G
Y4 6200 N N N N 20 100 N 20 L 20 10000
N N 50 200 N 20 L 30 G
Y5 A 7120 N N L 30 100 L
Y5B 71�p 500 7 100 0 100 30 150
YSC 7120 N N N 70 5 5p N 20 70 N 100
N N N 70 N L L L 2
Y5D 7120 L 00
N N 10 50 N L L N 100
Y5(1) 7120 N N N 150 7 50 N L 50
Y6(,) 7120 N N N N 5 50 N L L 20 100
6640 N 5 50 N 20
Y6A 6640 N N L L 50 L 20 L
Y7 7040 N N N N L L 50 100
Y7A 7040 N N 2p p 15 50 N 20 N 20 100
50
Y7B 7040 N N N L 50 N L 100 20 2000
Y8 N N N N L 50 L N L
6800 N N 10 150 20 70 N L L N L
Y8A 6800
Y8B N N N 20 5 50 N 20 2p L 100
G800 N N 50 100 30 50 L N L
Y8C 6800
Y8D N N L N 7 100 N 20 L 50 20 L
6800 N N 20 N 100 N 20 L 50 L
Y8D(1) 6800 N N 30 L N
Y9 6960 N 2000 L N N 20 10 L
Y9A N N 20 100 20 L 20 20 200
6960 N N 50 N L
Y10 6960 N N 2p 5 50 N I. 0 L N
Yll 7410 N -'0 100 5 50 L N N
Y12 7280 N N 10 100 5 50 N 20 2p L L
Y12A 7280 N N 10 N 7 L N 20 30 L N
Y13- 6800 N N �0 200 50 N L S L
SO 0 L
Y13A 6800 N N 10 L 10 50 N 2 50 L L
Y I -1 8000 N N L 20 15 50 N 20 10 L N
Y l iA 8000 N N 50 L 30 50 N 20 5 10 L
Y14 8000 N N 50 L 50 50 L 20 N 100
Y14C 8000 N N L L 5 50 10 L 20 N 200
Y 14D 8000 N N 0 20 200 50 N L L N 00
50 N 20 100 L IOOU
622
_ ( y
YELLOW PINE MINING DISTRICT
FIELD
NO.
ELEV
SC
SN
SR
V
Appendix
B
M002
6200
7
N
500
Yellow
Pine
Semi - Quantitative
Data (Continued)
ZR
TH
M010
6200
FIELD
N
500
100
10000
20
30
N
50
N
M032
6200
L
N
NO.
Y 14E
ELEV
BI
CD
CO
CR
CU
LA
MO
NB
NI
PB
20
Y 14
8000
8000
N
N
N
N
N
N
5
50
N
L
L
N
SB
1000
Y14(1)
8000
N
N
Io
20
L
50
50
N
L
20
L
G
Y15
8680
N
N
� 0
N
100
20
50
N
:L
10
L
100
Y16
8760
N
N
L
N
20
50
N
1
20
20
L
Y 16A
8760
N
N
L
50
10
50
N
L
30--
L
1000
Y17
8760
N
200
100
N
150
5
50
N
L
to
N
N
Y18
8880
N
N
'
N
30
50
N
20
50
10
N
Y 18A
8880
N
N
N
N
L
50
N
L
L
L
N
Y18B
8880
N
N
N
N
L
50
N
L
L
N
N
Y19
6160
N
N
N
N
7
50
N
L
20
N
L
Y20
6240
N
N
N
N
L
50
N
L
N
N
N
Y20A
6240
N
N
N
N
10
50
N
20
N
15
G
Y21A
6860
L
N
N
N
N
50
N
N
N
L
100
N
N
Y5B
7120
N
N
10
50
N
L
L
5
L
L
FIELD
NO.
ELEV
SC
SN
SR
V
M002
6200
7
N
500
200
10000
ZN
ZR
TH
M010
6200
7
N
500
100
10000
20
30
N
50
N
M032
6200
L
N
100
20
500
L
N
100
N
M034
6200
L
1!.
200
20
50
L
50
N
Mill
6200
L
N
300
20
5000
15
N
50
N
M113
6200
L
N
100
20
70
10
N
30
N
M130
6200
7
N
2000
200
G
10
N
N
Y1
6200
N
N
100
50
N
50
N
N
N
N
YIA
6200
N
N
N
100
N
L
L
100
N
YIB
6200
N
N
100
20
N
L
200
100
N
Y1C
6200
L
N
L
20
N
L
20
N
YID
6200
L
N
100
20
50
N
20
L
200
N
YIE
6200
5
N
100
50
50
50
L
100
N
2
6_00
5
N
500
50
20
20
L
200
N
Y3A
6200
5
N
150
50
L 10
L
150
N
Y3B
6700
L
20
N
L
15 0
N
Y3C
6200
N
N
L
20
N
L
L
20
N
Y3
6200
5
10
100
100
L
L
L
L
20
N
Y4
610 00
�0
N
1000
200
N
50
L
200
100
300
N
N
Y5B
7120
N
N
200
30
L
200
N
Y5C
7120
N
N
50
20
N
L
L
200
N
Y513
71,0
15
N
'0
50
N
N
L
L
50
N
Y50)
7120
L
N
L
10
30
L
200
N
Y5(2)
7120
L
N
L
20
N
N
L
L
N
Y6
66-40
L
N
300
L
N
50
L
L
N
Y6A
6040
5
N
300
20
2000
L
L
50
N
Y7
70=40
Zo
N
N
300
100
50
70
N
L
100
N
623
>% C j fir
COOKRO, SILBERMAN, BERGER
Appendix B
Yellow Pine Semi - Quantitative Data (Continued)
FIELD
NO.
Y7A
ELEV
SC
SN
SR
V
W
Y
ZN
ZR
TH
Y713
7040
7040
N
N
N
N
20
N
L
N
L
N
Y8
6800
20
N
N
N
L
20
N
L
N
200
N
Y8A
6800
L
N
N
100
L
30
L
200
N
Y813
'Y8C
6800
20
N
150
30
300
N
L
10
20
L'
200
N
6800
10
N
500
50
N
50
L
L
200 --
N
Y813
6800
N
N
200
50
N
N
N
200
N
Y8D(1)
6800
N
N
200
100
N
N
L
L
N
1'9
6960
20
N
L
100
N
50
L
L
50
N
Y9A
6960
L
N
N
30
N
L
L
200
N
N
Y10
6960
20
N
N
100
L
50
N
200
N
Yll
Y12
7440
20
20
200
100
N
50
N
200
N
Y12A
7280
7280
N
20
N
100
20
N
N
N
L
N
Y13
6800
5
N
N
N
100
N
50
N
200
N
Y13A
6800
L
N
100
500
50
10
N
N
30
L
500
N
Y14
8000
N
N
N
10
200
10
L
N
N
70
N
Y14A
8000
N
N
N
10
500
L
N
70
200
N
N
Y14B
8000
N
N
N
20
200
L
N
150
N
Y14C
8000
N
N
N
20
500
N
N
200
N
Y14D
Y14E
8000
10
N
N
50
200
100
N
500
N
Y14F
8000
8000
N
N
N
N
10
200
L
N
100
N
Y14(1)
8000
N
N
N
N
N
100
500
50
200
100
N
Y15
8680
10
N
500
10
100
1000
N
L
L
N
100
N
Y16
8760
N
N
N
100
N
N
N
L
100
N
Y 16A
8760
N
N
L
L
N
N
N
150
N
N
Y17
8760
N
N
N
100
N
50
L
200
N
N
Y18
8880
N
N
N
L
N
N
N
L
N
Y 18A
8880 -
N
N
N
L
N
N
N
L
N
Y18B
8880
N
N
N
L
N
N
N
L
N
Y19
6160
N
N
N
L
N
N
N
300
N
Y20
6240
N
N
N
L
N
N
N
100
N
Y20A
6240
N
N
N
L
N
N
N
L
N
Y21A
6860
L
N
500
50
N
N
N
200
N
624