Geology and Mineral Deposits of the

Minnie Moore and Bullion Mineralized Areas,

Blaine County, Idaho

By Paul Karl Link and Ronald G. Worl

U.S. Geological Survey Bulletin 2064-Y

U.S. Department of the Interior

U.S. Geological Survey

Prepared in cooperation with the Idaho Geological Survey,

Idaho State University, and the University of Idaho
U.S. Department of the Interior

Gale A. Norton, Secretary

U.S. Geological Survey

Charles G. Groat, Director

This publication is only available online at:

http://geology.cr.usgs.gov/pub/bulletins/b2064-y/

Any use of trade, product, or firm names in this publication

is for descriptive purposes only and

does not imply endorsement by the U.S. Government

Version 1.0 2001

Published in the Central Region, Denver, Colorado

Manuscript approved for publication January 8, 2001

Graphics by authors and Gayle M. Dumonceaux

Photocomposition by Gayle M. Dumonceaux
III

Contents

Abstract ......................................................................................................................................... 1

Introduction .................................................................................................................................. 1

Historical Perspective ................................................................................................................. 1

Past Production ............................................................................................................... 1

Exploration Activity ........................................................................................................ 7

Geologic Setting ........................................................................................................................... 7

Terrane Description........................................................................................................ 7

Host Rocks ....................................................................................................................... 7

Milligen Formation.................................................................................................... 7

Dollarhide Formation................................................................................................ 12

Structure and Metamorphism ................................................................................................... 12

Minnie Moore Area......................................................................................................... 12

Colorado Gulch.......................................................................................................... 12

Bullion Area ..................................................................................................................... 12

Host Structures for Mineralization .............................................................................. 14

Minnie Moore Area ................................................................................................. 15

Bullion Area .............................................................................................................. 18

Post-Mineralization Faults................................................................................................ 18

Mineral Deposits........................................................................................................................... 19

Classification ...................................................................................................................... 19

Mineralogy .......................................................................................................................... 20

Isotopic, Age, and Fluid Inclusion Data.......................................................................... 20

Description of Orebodies.................................................................................................. 20

Alteration............................................................................................................................. 20

Genesis and Ore Controls................................................................................................. 21

Exploration Guides........................................................................................................................ 21

References .................................................................................................................................... 21

1. Geologic map with mines and prospects of the Minnie Moore and Bullion

mineralized areas, Blaine County, Idaho ....................................................................... 2

2. Geologic map of the Minnie Moore mineralized area, Blaine County, Idaho .......... 14

3. Geologic map of the Bullion mineralized area, Blaine County, Idaho ....................... 16

4. Geologic cross section through the Minnie Moore and Silver Star Queens 

veins, Minnie Moore mineralized area ........................................................................... 18

5. Geologic cross section through the Snooze vein, Minnie Moore 

mineralized area ................................................................................................................. 18

6. Geologic cross section through the Red Elephant, Mayflower, Eureka, and 

Whale veins, Bullion mineralized area ........................................................................... 19

7. Geologic cross section through Colorado Gulch and Star Gulch, 

Minnie Moore mineralized area ...................................................................................... 20

Figures
IV

Tables

1. Production information for the Minnie Moore and Bullion mineralized areas,

Blaine County, Idaho .......................................................................................................... 4

2. Description of mines and prospects in the Minnie Moore and Bullion 

mineralized areas, Blaine County, Idaho ........................................................................ 8
1

Abstract

In the early 1880’s the discovery of rich ores in the Minnie 

Moore and Bullion mineralized areas sparked a rush to settle and 

develop the Wood River valley. Silver and lead discoveries in 

these areas spurred the boom in mining after completion of the 

Oregon Short Line Railroad to Hailey in 1883.

In both areas the ore comprises galena, sphalerite, and tetrahedrite in a gangue of siderite, calcite, or quartz. Minor goldbearing quartz veins are also present. The ore is in fissure and 

replacement veins along fracture systems that formed in Late 

Cretaceous time, after intrusion of nearby granodiorite or quartz 

diorite stocks. The ore formed under mesothermal conditions 

and heat was supplied by the nearby plutons. In the Minnie 

Moore area, the mineralized veins are cut by low-angle normal 

faults that are of probable Eocene age.

In the Minnie Moore mineralized area, the host rock is the 

middle part of the Devonian Milligen Formation, (the informal 

Lucky Coin limestone and Triumph argillite), which is the same 

stratigraphic level as the host ore in the rich Triumph mine 

northeast of Hailey.

In the Bullion mineralized area, the ore is hosted by the 

lower member of the Middle Pennsylvanian to Lower Permian 

Dollarhide Formation. Rich ore was mined in several tunnels 

that reached the Mayflower vein, a northwest-striking mineralized shear zone. 

The deposits are thought to be mainly mesothermal veins 

that formed in association with Cretaceous magmatism. The 

syngenetic stratiform model of ore formation has often been 

applied to these deposits, however, no evidence of syngenetic 

mineralization was found in this study. Faulting has displaced 

most of the major orebodies and thus has made mining these 

deposits a challenge.

Introduction

Much of the early settlement of the Wood River valley in 

the 1880’s stemmed from discoveries of silver-lead-zinc veins 

hosted by black argillite and limestone. The two most productive areas for the early miners were in the vicinity of the Minnie 

Moore mine (fig. 1, site 77) directly west of Bellevue and in the 

vicinity of the Bullion mine (fig. 1, site 14b) about 10 km (6.2 

mi) west of Hailey up Bullion Gulch and Red Elephant Gulch 

(Elk Creek). The Minnie Moore and Bullion mines were commonly discussed in the early literature (Lindgren, 1900) and the 

“Wood River type” of lead-silver-siderite ore was extensively 

described in older economic geology textbooks (Lindgren, 

1933). Detailed investigations of these areas were published by 

Umpleby and others (1930) when the mines were open and 

underground workings were accessible. Anderson and others 

(1950) presented the last detailed survey of the areas. After 

studying the trace element, sulfur isotope, and fluid inclusion 

data, Hall and Czamanske (1972) and Hall and others (1978) 

suggest that lead-silver deposits are mesothermal and formed by 

hydrothermal systems of meteoric water in faulted Paleozoic 

rocks near cooling plutons. 

Hall (1985), in a geologic overview of the central Idaho 

black-shale mineral belt, assigned the host rocks in both areas to 

the Middle Pennsylvanian and to the Lower Permian Dollarhide 

Formation. Wavra and Hall (1989) further restricted this assignment to the upper member of the Dollarhide Formation. Our 

geologic mapping does not support these assignments; instead 

we place the Minnie Moore orebodies in the middle part of the 

Devonian Milligen Formation and the Bullion orebodies in the 

lower member of the Dollarhide Formation. 

This paper briefly discusses the Minnie Moore (fig. 2) and 

Bullion (fig. 3) mineralized areas (see Worl and Johnson, 1995, 

page A2 for description of mineralized areas) in light of modern 

understanding of stratigraphic relationships. Previously unpublished geologic mapping conducted at 1:24,000 scale for both 

areas is presented and the important characteristics of the mineral deposits are reviewed, mainly by updating information 

contained in previous reports. 

Historical Perspective

Past Production

Ore was first discovered in the Wood River valley in 1880 at 

the site of the Minnie Moore mine (Hewett, 1930, p. 221). The 

1880’s were boom years. Construction of a large smelter in 

Ketchum in 1881 and completion of the Oregon Short Line to 

Hailey in 1883 and Ketchum in 1884 facilitated production.

Geology and Mineral Deposits of the

Minnie Moore and Bullion Mineralized Areas, 

Blaine County, Idaho

By Paul Karl Link and Ronald G. Worl
2 Geology and Mineral Deposits, Minnie Moore and Bullion Mineralized Areas, Blaine County, Idaho

43°30'

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Quarternary surficial deposits

Challis Volcanic Group, undifferentiated (Eocene)

Cretaceous intrusive rocks associated with the Idaho batholith

Wood River Formation (Lower Pennsylvanian to Middle Pennsylvanian)

Dollarhide Formation (Lower Permian to Middle Pennsylvanian)

Milligan Formation (Devonian)

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EXPLANATION

Figure 1 (above and facing page). Geologic map with mines and prospects of the Minnie Moore and Bullion mineralized areas, Blaine 

County, Idaho. Mines and prospects, shown by number, correlate with tables 1 and 2: 6, Red Cloud mine; 7, Pass Group mine; 8, Narrow 

Gauge mine; 10, New York-Idaho Exploration Co. property; 10a, Idahoan mine; 10b, Eureka mine; 10c, Whale mine; 10d, Garfield mine; 10e, 

Baystate mine; 12, Wolftone mine; 13, Red Elephant mine; 14, Mayflower mine property; 14a, Ophir (Durango) mine; 14b, Bullion mine; 14c, 

Mayflower mine; 14d, Jay Gould mine; 15, Climax mine; 18, Black Barb mine; 19, Arizona Group mine; 20, Liberty Gem mine; 69, Rawhide 1, 2, 

and 3 prospect; 70, Commodore property; 71, Snoose mine; 72, Grover Crocker mine; 74, Sunshine prospect; 75, Oswego prospect; 76, 

Penobscot mine; 77, Minnie Moore mine; 78, Silver Star Queens mine; 79, McIrvin prospect; and 80, Telluride prospect.
3

114°22'30"

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74 72

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Contact—Dashed where approximately located

Sheared unconformity—Arrows on stratigraphically

younger side

Low-angle normal fault—Dashed where approximately

located; double hachure on hanging wall

High-angle normal fault—Dashed were approximately

located; bar and ball on hanging wall

Mineralized vein—Showing dip

Site of mine or prospect—See tables 1 and 2

Prospect—Vein expression unknown

83

70

EXPLANATION

The Minnie Moore mineralized area (fig. 2) has the largest 

historical production of silver, lead, and zinc in central Idaho. 

The major producers were the Minnie Moore (fig. 2, site 77), Silver Star Queens (site 78), and Snoose mines (site 71). The most 

significant period of production was from 1880 to about 1905, by 

which time all known deposits had been discovered and mined.

The Minnie Moore mine was developed in several stages. 

Underground workings were developed prior to 1884, but there 

Historical Perspective
4 Geology and Mineral Deposits, Minnie Moore and Bullion Mineralized Areas, Blaine County, Idaho

Table 1. Production information for the Minnie Moore and Bullion mineralized areas, Blaine County, Idaho.

[Sites are plotted by site numbers on figure 1]

Site 

no.

Site Name Latitude (north)

Longitude (west)

Production Sources of 

data1

6 Red Cloud mine 43 31 5.35

114 26 50.3

Active between 1880 and 1902 with production of lead, 

silver, and gold worth $815,802. Active 1906–1925, 1941–

1950, 1973; several thousand tons of ore yielded silver, 

lead, zinc, copper, and gold. Property developed on 11 

levels; most production was from the number 9 level, 706 

ft below the surface

1, 3, 6

7 Pass Group mine 43 30 58.48

114 26 5.98

Production during the period 1885–1899 was 198.3 tons of 

ore yielding 0.14 ounces of gold, 18,254.7 ounces of 

silver, and 242,372 pounds of lead; in 1911 7 tons ore 

yielding 99 ounces of silver and 1,571 pounds of lead; in 

1940–1943 a few tens of tons yielding silver, lead and zinc 

2, 3, 6

8 Narrow Gauge mine 43 31 15.20

114 26 3.03

Production during the period of 1883–1903 was 1,306.3 

tons of ore that yielded 0.94 ounces of gold, 1,961 ounces 

of silver, and 19,650 pounds of lead

2, 3

10 New York–Idaho 

Exploration Co. 

property

43 29 56.60

114 24 57.7

During the period of 1883–1891 Eureka produced 1,079 

tons that yielded 82,733 ounces of silver and 10,548,390 

pounds of lead; Whale produced 253 tons that yielded 

24,410 ounces of silver and 311, 089 pounds of lead; Bay 

State produced 197 tons that yielded 29,610 ounces of 

silver and 216,038 pounds of lead; Garfield produced 37 

tons that yielded 4,053 ounces of silver and 43,003 pounds 

of lead; and King of Hill produced 47 tons that yielded 

4,175 ounces of silver and 59,285 pounds of lead. During 

the period 1905–1923 Eureka produced 9,200 tons that 

yielded 0.02 ounces of gold, 144,962 ounces of silver, 

1,755,000 pounds of lead and 12,268 pounds of copper. 

Eureka was also active in 1939 and 1968–1972, producing 

a few tens of thousands of tons of ore yielding significant 

silver, lead, zinc, copper, and some gold. Post-1902 

production of a few tens of tons of ore from the Bay State 

and Whale yielded silver, lead, zinc, and copper

2, 3, 6

12 Wolftone mine 43 29 26.46

114 28 43.6

Several tunnels; the Sweed, the longest, totals about 2,000 

ft. Production 1883–1898 totaled 262.3 tons yielding 0.13 

ounces gold, 17,839 ounces silver, 244,583 pound lead, 

and 177 pounds copper. Production 1921–1927 of a few 

tons of ore yielded silver, lead, zinc and some copper and 

gold

3, 6

13 Red Elephant mine 43 29 55.50

114 25 34.6

9,000 feet of workings on six levels; most ore was from 

level 2, and none was from below level 5. Production 

during the period 1882–1900 was 8,231 tons that yielded 

9.44 ounces of gold, 834,601 ounces of silver, and 

8,655,493 pounds of lead and 781,433 pounds of copper; 

1904–1918 6,927 tons that yielded 42.56 ounces of gold, 

125,099 ounces of silver, and 853,409 pounds of lead; 

1927–1947 a few thousand tons of ore yielded significant 

silver, lead, zinc, copper, and gold

1, 2, 3, 6
5

Table 1. Production information for the Minnie Moore and Bullion mineralized areas, Blaine County, Idaho—Continued.

[Sites are plotted by site numbers on figure 1]

14 Mayflower mine 43 29 39.42

114 24 41.9

Production was from the Ophir, Bullion, Mayflower, Jay 

Gould, and other workings along one vein system. Jay 

Gould production during the period 1882–1906 was 

40,019 tons yielding 4.78 ounces of gold, 422,565 ounces 

of silver, and 5,283,000 pounds of lead. Mayflower 

production during the period 1882–1901 was 3,606 tons 

yielding 545,493 ounces of silver and 4,308,000 pounds of 

lead. Bullion production during the period 1881–1908 was 

3,276 tons yielding 485,182 ounces of silver and 

3,518,000 pounds of lead. Ophir (Durango) production 

during the period 1888–1891 was 62.5 tons yielding 4,834 

ounces silver and 24,205 pound lead. The Jay Gould 

(including the Apache workings) recorded several 

thousand tons of production, yielding silver, lead, zinc, 

copper, and gold in the period 1907–1917, 1925, 1933–

1935, and 1948–1951. The Bullion has had intermittent 

production amounting to a few tens of tons of ore since 

1908

1, 2, 3, 6

15 Climax mine 43 29 58.65

114 20 40.2

Production (mill) value of $80,000 1880’s to 1950. Series 

of tunnels

1, 2, 3

18 Black Barb mine 43 29 1.74

114 28 19.3

Production 1889–1908 was 30.1 tons yielding 493 ounces 

gold, 1,741.7 ounces silver, and 29,862 pounds lead

2

19 Arizona Group mine 43 29 59.33

114 24 13.3

Production during the period 1888–1901 was 7.78 tons 

yielding 593 ounces silver and 7,781 pounds of lead; 

1917–1918 65 tons yielding 3,637 ounces of silver and 

57,610 pounds of lead; 1922–1925 silver, lead, and copper

2, 6

20 Liberty Gem mine 43 27 23.97

114 26 16.9

Worked intermittently since 1927; production of several 

hundred tons of ore yielded silver, lead, zinc, copper, and 

gold. Two shafts, 230 ft and 210 ft deep

1, 6

69 Rawhide 1, 2 & 3 

prospect

43 29 27.53

114 18 56.0

Dozer cuts and 40 ft of tunnel 4

70 Commodore property 43 29 36.50

114 20 56.0

Dozer cuts and trenches, limited early production 5

71 Snoose mine 43 29 21.53

114 19 20.1

Production was prior to 1900, 1922–1923, 1930, 1941–

1953. Production 1944–1950 4,416 tons yielding 181 

ounces of gold, 16,997 ounces of silver, 445,766 pounds 

of zinc, 192,478 pounds of lead, and 16,398 pounds of 

copper. Several long tunnels and a 225 foot deep shaft; 

several hundreds of feet of working on the 100- and 200-

foot levels

6

72 Grover Crocker mine 43 28 45.41

114 17 32.6

Worked intermittently prior to 1900, 1911–1940, and 

1959–1961. Production (mill) value of $60,000 of leadsilver ore reported for the early days (prior to 1900); later 

production of a few hundred tons of ore yielded significant 

silver, lead, zinc, and some gold and copper. Four tunnels 

and an inclined shaft

1, 6

74 Sunshine prospect 43 28 45.18

114 18 18.3

Several tunnels 1

75 Oswego prospect 43 28 29.46

114 18 13.9

A few tens of tons of ore yielded silver and lead. Inclined 

shaft about 200 ft deep and five or six tunnels

1, 6

76 Penobscot mine 43 27 55.11

114 17 5.80

565-foot long tunnel and a 200-foot long tunnel. 

Production for 1883, 1887, 1900 totaled 1,005.6 ounces of 

silver and 17,000 pounds of lead

1, 2

Historical Perspective
6 Geology and Mineral Deposits, Minnie Moore and Bullion Mineralized Areas, Blaine County, Idaho

was only minor production. From 1884 to 1889, extensive operation yielded much of the mine’s total production, and the mine 

was developed to the 900-foot level, at which point operations 

ceased because the ore was cut off at the flat Rockwell fault (fig. 

2). Hewett (1930) gave an apparent profit for the period 1886–

1889 of more than $625,000. The mine was reopened in 1900, 

and shortly after the continuation of the orebody was discovered 

below the Rockwell fault. This discovery spurred a major period 

of production from 1902 to 1906; however the orebody was 

found to be cut again at the 1000-foot level against the Minnie 

fault (fig. 2, section A-A'; fig. 4), and major operation ceased in 

1906. Sporadic exploration to find a continuation of the orebody 

beyond the Minnie fault continued until 1927, at which time the 

mine was closed. During the period 1907–1920 tailings from 

previous operation were milled. 

In 1932, the Rockwell shaft was sunk to explore the southeast extension of the Silver Star Queens (fig. 1, site 78, Queen of 

the Hills) vein, and three years later the Hershey crosscut was 

driven to explore the southeast extension of the Minnie Moore 

vein system. The mine was out of operation from about 1935 

until the 1940’s at which time the Rockwell shaft was reopened 

and the Queen of the Hills (Silver Star Queens) vein systems 

were mined. Some of the ore mined in the 1940s appears to 

have also come from the Minnie Moore mine and Minnie Moore 

footwall vein systems. The Silver Star Queens operations 

ceased in the early 1970’s. 

The Snoose mine (fig. 1, site 71), in Colorado Gulch north 

of the Minnie Moore and Silver Star Queens mines (fig. 2, 

section B-B'; fig. 5), had its major period of production during 

the 1940’s. Several smaller mines near the Snoose produced 

small amounts of lead-silver ore on an intermittent basis from 

1900 into the 1980’s. 

The Bullion mineralized area includes the Red Elephant 

mine (fig. 1, site 13) in Red Elephant Gulch and the Mayflower 

Table 1. Production information for the Minnie Moore and Bullion mineralized areas, Blaine County, Idaho—Continued.

[Sites are plotted by site numbers on figure 1]

77 Minnie Moore mine 43 28 1.55

114 17 32.1

Extensive workings include three included shafts, the 

Minnie Moore at 30° to 1,100 ft slope length, the Relief at 

20° to 800 ft slope length, and the Allen at 35° to a slope 

length of 850 ft, and the Rockwell vertical shaft that is 500 

ft deep. Production 1881–1886 yielded 1, 059,205 ounces 

of silver and 14,206,266 pounds of lead; 1902–1906 

57,632 tons of ore yielding 1,347,341 ounces of silver and 

15,348,125 pounds of lead. From 1907–1926 reworked 

tailings from the Minnie Moore and Queen of the Hills 

mines and a small amount of crude ore totaling 60,896 

tons yielded 109.7 ounces of gold, 212,977 ounces of 

silver, 1,896,349 pounds of lead, and 21,686 pounds of 

copper. The mine also recorded production in 1935 and 

1941–1947. Promotional information circulated during the 

1930’s by various groups interested in the Minnie Moore 

mine listed a probable total production of 168,000 tons 

that averaged about 27 ounces silver per ton and 14.75 

percent lead

1, 2, 3, 6

78 Silver Star Queens 

mine

43 28 12.22

114 17 22.7

750-foot long Moulton tunnel, the 2,475-foot long Lusk 

tunnel, and an inclined shaft to a vertical depth of 354 ft. 

Production 1884–1890 was 11,377 ton having a gross 

(mill) value of $1,265,608. The mine also recorded 

production in 1913–1914, 1923, 1926, and 1952–970. 

Total production to 1950 estimated at $2,500,000. 

Recorded post-1902 production of several hundred 

thousand tons of ore yielded significant silver, lead, zinc, 

and copper, and some gold and antimony

1, 2, 3, 6

79 McIrvin prospect 43 27 32.35

114 16 38.0

Four caved tunnels 1

80 Telluride prospect 43 27 19.33

114 16 28.7

Two closely spaced tunnels at the same level 1

1

Sources of data:

1, Anderson and others (1950)

2, Umpleby and other (1930)

3, Lindgren (1900)

4, Staley (1962)

5, U.S. Geological Survey, Spokane Field Office, DMEA files

6, Mitchell and others (1991)
7

(site 14c), Bullion site (site 14b), Jay Gould (site 14d), and 

Ophir (site 14a) mines in Bullion Gulch (Fryklund, 1950). The 

four mines in Bullion Gulch are interconnected and lie along the 

major northwest-striking Mayflower fault zone (fig. 3, section 

D-D'; fig. 6). Very rich lead-silver ore was mined from 1880 to 

1889 and the town of Bullion flourished. Old tailings were 

treated starting in the summer of 1949, after the construction of 

a 100-ton mill.

Exploration Activity

The region experienced several surges of exploration for 

base- and precious-metals that coincided mainly with periods of 

production of the major mines. The U.S. Government Defense 

Minerals Exploration Administration (DMEA) exploration program supported work in the Silver Star Queens mine during the 

1950’s. 

The most recent systematic exploration activity in these 

areas took place during the early 1980’s when the central Idaho 

black-shale mineral belt (Hall, 1985) was evaluated by several 

major mining companies for bedded syngenetic massive sulfide 

deposits. The Minnie Moore and Bullion mineralized areas 

were major targets because of host-rock lithology and the massive tubular nature of some of the orebodies. Exxon Minerals 

drilled several exploration holes in the Bullion area, and Getty 

Minerals supported new exploration and drilling in the Triumph 

area (Turner and Otto, 1995). In 1994, however, there is little 

exploration activity in either the Minnie Moore or Bullion areas. 

The two areas are close to the rapidly growing Wood River valley and any further mineral exploration will have to consider 

societal impacts of mining on this developing area.

Geologic Setting

Terrane Description

The Minnie Moore and Bullion mineralized areas are in 

carbonaceous argillite, limestone, and fine-grained sandstone of 

the Devonian Milligen Formation and the Middle Pennsylvanian 

to Lower Permian Dollarhide Formation, and are in the central 

Idaho black-shale mineral belt (Hall, 1985). The Paleozoic 

rocks are intruded by Late Cretaceous granitoids: the Croesus 

stock (quartz diorite) immediately west of the Minnie Moore 

area and the Deer Creek stock (granodiorite) immediately east 

of the Bullion area. 

Host Rocks

Milligen Formation

The Minnie Moore mineralized area (fig. 2) is underlain 

mainly by the Devonian Milligen Formation. In the northeastern 

part of the area the Milligen lies unconformably beneath the 

Middle Pennsylvanian Hailey Member of the Wood River Formation. On the west side of the Minnie Moore area, the Milligen 

is interpreted to lie unconformably beneath the Middle Pennsylvanian to Lower Permian lower member of the Dollarhide Formation, although a basal conglomerate is not present and 

exposures are poor.

In the Triumph area, 16 km (10 mi) to the northeast, the 

Milligen Formation contains mappable informal members 

(Turner and Otto, 1988, 1995; Link and others, 1995). There, 

the Milligen Formation is at maximum 647 m (2,000 ft) thick 

and consists of a lower member of black argillite, purple siltite, 

and bedded chert (more than 48 m [150 ft] thick), a middle section containing black calcareous argillite and bedded chert (the 

informal Triumph argillite, as thick as 152 m [500 ft] thick), and 

lenticular intervals of coarse-grained sandstone (the informal 

Cait quartzite, 1–20 m [0–66] thick) and dark-gray to black carbonaceous silty limestone (the informal Lucky Coin limestone, 

as thick as 244 m [800 ft]). The upper 183 m (600 ft) of the Milligen Formation contains dark- to light-gray and brown finegrained sandstone and minor black argillite, purple siltite, chert, 

and conglomerate (the informal Independence sandstone). Recognition of these members in the Minnie Moore area allowed 

mapping of the divisions shown on figure 2, although the units 

are generally thinner than in the Triumph area and the section is 

attenuated by faulting.

There has been disagreement, especially in the wave of 

exploration of the last fifteen years, about the formation assignment of the rocks in Minnie Moore and Bullion areas (compare 

our maps with those of Hall, 1985, and Wavra and Hall, 1989). 

Late in his life, W.E. Hall changed his assignment of the host 

rock in both areas from Milligen to Dollarhide Formation. C.S. 

Wavra carried this line of reasoning farther and assigned the host 

rocks in both areas to the upper member, Dollarhide Formation. 

The root of this stratigraphic confusion is that carbonaceous 

black shale or siltstone of the Triumph argillite (Milligen Formation) resembles similar fine-grained strata in both the upper 

and lower members of the Dollarhide Formation. Also, darkgray limestone of the Lucky Coin limestone resembles similar 

limestones of the lower member of the Dollarhide Formation. 

Recognition in the Minnie Moore area of the stratigraphic units 

present in the Triumph area, and especially the coarse-grained 

sand grains of the Cait quartzite in the immediate area of the 

Minnie Moore mine supports, however, our interpretation that 

the strata belong to the Milligen Formation, as designated by 

Hewett (1930) and Anderson (1950). 

Anderson (1950, p. 15) reported that mine geologists (R.T. 

and W.J. Walker) at the Minnie Moore mine informally divided 

the Milligen Formation from bottom to top into the Defiance 

argillite (±800 ft [248 m]), the Penobscot “formation” (containing 30 ft [9 m]) of lower Penobscot limestone, 40 ft [12 m] of 

intermediate argillite, and 80 ft [24m] of upper Penobscot limestone, and the Michigan argillite (±100 ft [30 m]). We interpret 

the Penobscot unit to correlate with the Lucky Coin limestone 

and the surrounding argillites to belong to the Triumph argillite 

and the lower argillite member. Quartzite is reported, though it 

is described as fine grained. Neither Hewett (1930) nor Anderson (1950) reported the coarse-grained sandstone beds that we 

correlate with the Cait quartzite.

Geologic Setting
8 Geology and Mineral Deposits, Minnie Moore and Bullion Mineralized Areas, Blaine County, Idaho

Table 2. Description of mines and prospects in the Minnie Moore and Bullion mineralized areas, Blaine County, 

Idaho.

[Mines are prospects are plotted by site numbers on figure 1. First synonym is map number from Hustedde and others (1981) (for example 813), second synonym is the USGS Mineral Resources Data System record number (for example WO13678). Commodities are listed in approximate decreasing 

order of importance. Mineral deposit types: 19A, polymetallic replacement deposits; 22E, polymetallic veins in black shale; 22H, polymetallic quartz 

veins and lodes. Locations and information sources are given in table 1]

Site 

No.

Site name

(synonyms)

Deposit 

type

Commodities present Description

6 Red Cloud mine

158

WO13595

22E Pb, Ag, Au, Cu, Zn Three major vein systems: Red Cloud strikes N. 23° W. 

and dips at a high angle west; Hanging Wall, a splay off 

the Red Cloud strikes N. 50° W. and dips 60° SW.; and 

Ridge is an unproductive vein that strikes N. 45° W. and 

dips 70°–90° SW. Ore bodies are mostly galena and 

sphalerite in a siderite gangue that contains locally 

abundant quart and arsenopyrite.

7 Pass Group mine

159

WO13692

Argent claim

22E Ag, Pb, Au Main orebody is irregularly shaped and at the intersection 

of northwest-trending fracture systems in dark calcareous 

argillite. Ore is in clayey gouge zones as wide as 6 ft; the 

gouge is locally replaced by vein quartz. Abundant pyrite 

and sparse galena, sphalerite, chalcopyrite, and 

tetrahedrite are in the quartz.

8 Narrow Gauge

mine

160

WO13698

22E, 

22H

Ag, Pb, Zn, Au, Cu Narrow fissure vein in black calcareous argillite strikes 

northwest and dips steeply southwest. High-grade ore 

consists of galena, sphalerite, and chalcopyrite that is 

present as streaks and bands in a siderite gangue.

10 New York-Idaho 

Exploration Co. 

Property

167

King of the Hills

a. Idahoan 191

WO1390

b. Eureka 183

WO13605

c. Whale 182

WO13689

d. Garfield 174

WO13691

e. Baystate 161

WO13688

22H, 

19A, 

22E

Ag, Cu, Pg, Au Several properties are along the main fracture system that 

trends N. 40° W. and along several subsidiary fracture 

systems. These fracture systems in places show little 

evidence of mineralization. Ore is present as fissure 

fillings and replacement of country rock in places in 

unfractured rock at a distance from the fissures. Ore 

consists of galena, sphalerite, and tetrahedrite in a gangue 

of crushed country rock, quartz, siderite, calcite, and 

pyrite. Ore was mostly low grade, averaging 8 percent lead 

and 9 ounces of silver per ton but locally was as high as 60 

percent lead and 65 ounces of silver per ton.

12 Wolftone mine

171

WO13710

22E Ag, Pb, Cu, Zn, Au Deposits are along three vein systems. One system strikes 

about north and is vertical; a second strikes a little east of 

north and dips 35° E.; and the third strikes N. 30° W. and 

dips 20°–40° SW.

13 Red Elephant mine

172

WO13672

22E, 

19A, 

22H

Pb, Ag, Zn, Au, Cu Ore consisting of galena, sphalerite, and tetrahedrite in a 

gangue of siderite, calcite, quartz, and pyrite is present as 

fissure filling and replacement along a major northwesttrending fault system. Host rock is dark calcareous 

argillite. The ore-bearing part of the fissure has roughly the 

form of a blunt wedge pointing downward. The vein is cut 

by a major fault with a 3–6-foot-wide zone of gouge that 

strikes N. 30° W. and dips 60° SW. Five distinct orebodies 

were worked, mostly on level 2. Much of the outcrop of 

the vein is a siliceous gossan as wide as 10 ft.
9

Table 2. Description of mines and prospects in the Minnie Moore and Bullion mineralized areas, Blaine County, 

Idaho—Continued.

[Mines are prospects are plotted by site numbers on figure 1. First synonym is map number from Hustedde and others (1981) (for example 813), second synonym is the USGS Mineral Resources Data System record number (for example WO13678). Commodities are listed in approximate decreasing 

order of importance. Mineral deposit types: 19A, polymetallic replacement deposits; 22E, polymetallic veins in black shale; 22H, polymetallic quartz 

veins and lodes. Locations and information sources are given in table 1]

14 Mayflower mine

179

WO13676

a. Ophir (Durango)

b. Bullion 190

c. Mayflower

d. Jay Gould 178

22E, 

22H, 

19A

Pb, Ag, Zn The Mayflower vein strikes N. 50° W. and dips 45°–60° 

SW. Ore is in lenticular bodies as thick as 50 ft and several 

hundred feet long that formed from fissure filling and 

replacement of black calcareous argillite country rock. 

Some of the orebodies are flat-laying lenses that extend 

away from the fissure zone. Vein material is generally 

within distinct walls as much as 12 ft apart, but locally 

vein walls are indistinct and the vein is defined by 

disseminated calcite, siderite, and pyrite in argillite. Ore 

consists of galena, tetrahedrite, sphalerite, and minor 

chalcopyrite in a gangue of siderite and minor quartz and 

post-ore calcite. There is about 40 ft of oxidation, and the 

surface expressions are siliceous gossans. Higher grade ore 

averaged 90–125 ounces of silver per ton and 50–65 

percent lead.

15 Climax mine

184

WO13662

22E Pb, Ag, Zn, Au, Cu Several mineralized fracture or fissure zones strike 

northwest and dip northeast; the main ore zone trends west 

and dips south as much as 60°. Host rocks are folded and 

extensively faulted carbonaceous and limey shale. 

Orebodies composed of galena, tetrahedrite, sphalerite in a 

gangue of siderite are offset by a series of almost flat 

faults.

18 Black Barb mine

189

WO13711

22E Ag, Pb, Au Unknown.

19 Arizona Group

mine

192

WO13709

22E Ag, Pb, Cu Arizona vein strikes about N. 30° W., dips very steeply to 

the southwest, and is hosted by dark calcareous argillite.

20 Liberty Gem mine

234

WO13591

22E Pb, Ag, Au, Zn Three veins are reported, but only one has been productive. 

The productive vein is 30 in. thick, and strikes N. 15° W., 

and dips 48° SW. Irregular masses of lead ore are in fault 

gouge in a shear zone. A 1939 assay of crude ore was 0.15 

ounces per ton gold, 18.4 ounces per ton silver, and 18.9 

percent lead.

69 Rawhide 1, 2, & 3 

prospect

185

22E Zn, Ag, Pb, Au Oxidized zone in shale contains oxide minerals of zinc, 

manganese, and iron in siderite gangue. One grab sample 

contained 0.02 ounces of gold per ton, 3.19 ounces of 

silver per ton, 12.5 percent zinc, and 2 percent lead.

70 Commodore property

193

22E, 

22H

Zn, Ag, Pb Calcite and quartz veinlets containing some siderite within 

the fractured zone and hanging wall of a 40–60-foot-wide 

northwest-trending, northeast-dipping fault zone. Sulfide 

minerals are present as disseminations in the black shale 

wall rock and the vein material and are mainly 

concentrated in the hanging wall.

Geologic Setting
10 Geology and Mineral Deposits, Minnie Moore and Bullion Mineralized Areas, Blaine County, Idaho

Table 2. Description of mines and prospects in the Minnie Moore and Bullion mineralized areas, Blaine County, 

Idaho—Continued.

[Mines are prospects are plotted by site numbers on figure 1. First synonym is map number from Hustedde and others (1981) (for example 813), second synonym is the USGS Mineral Resources Data System record number (for example WO13678). Commodities are listed in approximate decreasing 

order of importance. Mineral deposit types: 19A, polymetallic replacement deposits; 22E, polymetallic veins in black shale; 22H, polymetallic quartz 

veins and lodes. Locations and information sources are given in table 1]

71 Snoose mine

194

Jensen-Stevens 

mine

Dickey mine

Pacific mine

22E, 

22H

Ag, Pb, Zn, Cu, Au Two types of mineralized veins are in the Snoose mine: 

polymetallic veins and a polymetallic quartz vein and lode. 

The two main polymetallic veins (Footwall and 

Hangingwall veins) are parallel, about 90 ft apart, trend 

northwest, and dip northeast. The Footwall vein strikes N. 

45° W. and dips 50° NE. at the surface and 30° NE. at the 

150 foot level. This vein is 2–18 ft wide. The Hangingwall 

vein is in a shear zone that is about 40 ft across. Strike of 

the vein ranges from N. 28° W. to W. Dip of this vein 

system ranges from 57°–64° NE. on the footwall and from 

65° to 75° NE. on the hanging wall. Ore composed of 

brownish sphalerite, fine-grained galena, tetrahedrite, 

pyrite, marcasite, and minor amounts of qaurtz and siderite 

is distributed in the shear zone as bunches and stringers. 

One bin of ore contained 25–30 percent lead, 20 percent 

zinc, 75 ounces of silver per ton, and .22 ounces of gold 

per ton. The polymetallic quartz vein and lode is similar to 

the veins in the Magdalena and Croesus mines (Worl and 

Lewis, in press) and may represent an eastern extension of 

those vein systems. This vein system, which strikes west 

and dips 60° S., contains an ore shoot 300 ft long and 

several ft wide that has values in gold and silver. The thinbedded blackish argillite and limestone wall rocks strike 

about N. 55° W. and dip 60° SW.

72 Grover Crocker 

mine

195

WO13657

Queen Bess

22E Ag, Pb, Zn, Au, Cu Orebodies worked prior to 1900 were lodes 2–3 ft wide. 

Recently worked ore bodies consist of 6–12 inch zones of 

thin seams, small bunches, and pods of siderite with some 

brownish sphalerite, cubic and gneissic galena, and 

scattered crystals of arsenopyrite. This ore is associated 

with “rolls” with a northeast dip in a major crushed zone 

that strikes N. 80° W. and dips southwest. The black 

argillite host rocks show considerable variation in attitude.

74 Sunshine prospect

204

WO13660

22E, 

19A

Pb, Ag Several hundred feet workings in several short tunnels in 

argillite and black limestone. No data are available on the 

mineral deposits.

75 Oswego prospect

205

WO13658

22E, 

19A

Pb, Ag Workings explore three mineralized zones. (1) A bedded 

vein in white marblized limestone with walls about 6 ft 

apart, but no visible ore remains. (2) A vein in white 

marblized limestone composed of several feet of oxidized 

material and strikes N. 20°–30° W. and dips 60° NE. (3) A 

zone of fissuring 8–10 ft wide in argillite strikes N. 35°W., 

dips 70° SE. and contains prominent bands of iron and 

manganese oxides.

76 Penobscot mine

218

WO13653

Riverview

22E, 

19A

Pb, Ag, Sb, Zn A N. 9° W. -trending shear zone that dips 60°SW. in shale 

and argillite contains some pods and stringers of quartz 

and calcite, and in places galena, arsenopyrite, stibnite, 

and sphalerite. In one location siderite, sphalerite, and 

pyrite are present as replacement of shale.
11

Table 2. Description of mines and prospects in the Minnie Moore and Bullion mineralized areas, Blaine County, 

Idaho—Continued.

[Mines are prospects are plotted by site numbers on figure 1. First synonym is map number from Hustedde and others (1981) (for example 813), second synonym is the USGS Mineral Resources Data System record number (for example WO13678). Commodities are listed in approximate decreasing 

order of importance. Mineral deposit types: 19A, polymetallic replacement deposits; 22E, polymetallic veins in black shale; 22H, polymetallic quartz 

veins and lodes. Locations and information sources are given in table 1]

77 Minnie Moore mine

219

WO02482

Relief

 213

22E, 

19A

Ag, Pb, Cu, Au, Zn Several roughly parallel fissure veins of northwest strike 

and southwest dip are in argillite and limestone a short 

distance from the contact of quartz diorite and sedimentary 

rocks. The veins dip approximately parallel to the contact. 

The Minnie Moore vein strikes west-northwest and dips 

25°–35° SW. but in places is almost horizontal. This vein 

may be along a thrust fault that is almost parallel, with, but 

locally crosscuts bedding. The Minnie Moore orebody is 

blanketlike and varies considerably in thickness and grade. 

The ore zone is 1,200 ft long and composed of individual 

bodies as long as 400 ft and as wide as 18 ft. The orebody 

is zoned; the western zone composed of a band of massive 

siderite several ft thick containing 2 percent lead and 46 

ounces per ton silver. The eastern zone is composed of 

calcite and sulfide minerals and the middle zone grades 

from sphalerite ore to calcite ore. There was no change in 

this pattern of zoning through 1,400 ft of depth. Most off 

the ore mined averaged 10 percent lead and 20 ounces per 

ton silver (milling ore). Some of the ore was direct 

shipping ore composed of solid galena that was in bands 

and lenses a few inches to 10 ft thick. The Minnie Moore 

vein system closely parallels, but does not cut the contact 

with the quartz diorite. The Bergman vein, which strikes 

N. 30° W. and dips 40°–45°W. also closely parallels the 

quartz diorite contact and follows a single lithologic unit 

and may be a continuation of the Minnie Moore vein. The 

McIrvin vein is 2,000 ft southeast along strike of the 

Bergman vein and is probably a continuation of that vein. 

Several veins in the Minnie Moore vein footwall have a 

similar northwest strike but dip at a steeper angle. Host 

rocks generally strike northwest and dip 30° SW. and are 

folded around an axis that plunges south.

78 Silver Star

Queens mine

221

WO60186

Queen of the Hills

22E, 

19A

Pb, Zn, Ag, Cu, Sb, Sn Two parallel vein systems are about 100 ft apart; the 

Hangingwall vein strikes N. 70° W. and dips 60°–65° SW. 

and the footwall vein is a splay of the Hangingwall vein. 

The main orebody had a stope length of 500 ft and was 

made up of sulfide lenses, including dark-brown 

sphalerite, 2–6 ft thick. Ore is present as a fracture filling 

of open space and as a replacement of wallrock. Marcasite 

present as a film coating on the other sulfide minerals 

suggests that the calcite and marcasite may have been 

deposited at a later time. Host rocks of black siliceous 

argillite strike N. 40°–50° W. and dip 25°–35° SW. and are 

folded.

79 McIrvin prospect

231

WO13655

22E Pb, Zn, Sb A small vein strikes N. 60° W. and dips 60°SW. and is a 

possible extension of the Bergman vein in the Minnie 

Moore mine. Ore is reported to have been jamesonite, 

stibnite, and reddish brown sphalerite. Black argillite along 

the mineralized zones has been silicified and pyritized and 

locally contains massive quartz and much pyrite.

80 Telluride prospect

823

WO13656

22E Pb, Zn A vein of quartz and gossan in black argillite and gray 

limestone contains reddish sphalerite, galena, and some 

pyrite. The vein strikes N. 70° E. and dips steeply 

southeast.

Geologic Setting
12 Geology and Mineral Deposits, Minnie Moore and Bullion Mineralized Areas, Blaine County, Idaho

Dollarhide Formation

Regionally the Dollarhide Formation is as thick as 2,000 m 

(6,560 ft) (Wavra and others, 1986) and contains three informal 

members (Mahoney and others, 1991; Link and others, 1995). 

The strata present at the west end of Minnie Moore Gulch are 

thought to belong to the lower member of the Dollarhide Formation (more than 800 m [2,640 ft] thick) because they contain 

thick black limestone beds and gray sandstone beds that are 

nowhere coarser than fine grained, an attribute that distinguishes 

sandstones of the Dollarhide Formation from the coarse-grained 

sands of the Cait quartzite in the Milligen Formation. Further, as 

stated by Wavra and Hall (1989), limestones are uncommon in 

the upper member of the Dollarhide Formation; thus that assignment is doubtful for the ore hosts in Minnie Moore Gulch. 

Structure and Metamorphism

Minnie Moore Area

In the Minnie Moore area, the Late Cretaceous Croesus 

quartz diorite stock to the west has produced contact metamorphism in limestones of the Milligen Formation. Minerals 

include diopside, tremolite, biotite, tourmaline, wollastonite, 

garnet, and scapolite(?) (Hewett, 1930).

The Minnie Moore area contains tight and locally eastward 

overturned map-scale folds (Lindgren, 1900), as well as local 

areas of mesoscopic folds. In several places in the Wood River 

area, including Colorado Gulch in the Minnie Moore area, the 

Milligen Formation contains two generations of folds, an earlier 

set of small-scale folds probably formed during the Devonian 

and Mississippian Antler Orogeny and a later large-scale set 

probably formed during the Cretaceous Sevier Orogeny (Turner 

and Otto, 1988, 1995; Burton and Link, 1995). Wavra and Hall 

(1989) used the presence of a cleavage or foliation as a means to 

distinguish Milligen Formation. We found, however, that structural fabric in the Milligen is heterogeneous and that the formation does not contain the same structural elements everywhere.

The mineralized Milligen Formation in Minnie Moore 

Gulch is at the crest of a regional anticline with Wood River Formation on the east and Dollarhide Formation on the west. In 

Minnie Moore Gulch, bedding in the Milligen Formation generally strikes northwest and dips steeply. This section is shown as 

west-facing and in stratigraphic order on the upright limb of an 

eastward overturned anticline on figures 2 and 4 (section A-A'). 

Detailed mapping would probably reveal local structural complexities in the overturned anticline. The argillites on the east 

end of Minnie Moore Gulch are tentatively mapped as the lower 

argillite member of the Milligen Formation. 

Colorado Gulch

Several critical geologic relations were identified in Colorado Gulch that were key to the interpretation of the structure in 

the Minnie Moore area (fig. 2, section B-B'; fig. 5). The identification of the host rocks at the Snoose mine as Milligen or Dollarhide Formations, has been contentious. Hall (1985) and Wavra 

and Hall (1989) labeled these rocks as Dollarhide Formation, in 

contrast to earlier reports. We, however mapped the sheared Milligen-lower Dollarhide contact west of the Snoose mine (fig. 2). 

The ore-bearing vein in the Snoose mine is hosted by folded 

black argillite and limestone of the Lucky Coin limestone, 

Devonian Milligen Formation.

Our mapping shows several eastward overturned folds in 

the Milligen Formation and unconformably overlying Eagle 

Creek member of the Wood River Formation (fig. 2) in Colorado 

Gulch. Sheared pods of Hailey Member of the Wood River Formation are exposed along this unconformity. This contact was 

mapped as the “Wood River thrust fault” by Hall (1985), however it is now thought to be a locally sheared unconformity 

(Burton and others, 1989; Rodgers and others, 1995).

Rocks assigned to the lower member of the Dollarhide Formation are present on the west (upper) ends of Colorado and Star 

Gulches in a northward-widening band east of the Croesus stock. 

This is one of the few places where the Dollarhide and Milligen 

Formations are in contact. The exposed contact is sharp and linear, and beds are parallel across it. These features suggest that 

the contact is a sheared unconformity, comparable to the sheared 

unconformity between the Milligen and Wood River Formations; 

on the west limb of the anticline, the contact is exposed east of 

the Snoose vein (fig. 2, section B-B';fig. 5). A low-angle, shallow 

dipping, top-to-the-west normal fault cuts the upper parts of the 

Colorado Gulch. Between Colorado and Star Gulches, this fault 

cuts the Snoose vein in its footwall. The fault also cuts the ridge 

to the north of Colorado Gulch, but no members of the Milligen 

Formation were not mapped in this area.

Bullion Area

The Bullion mineralized area (fig. 3) is underlain by the 

lower and middle members of the Pennsylvanian and Permian 

Dollarhide Formation, which are folded into upright and westoverturned map scale folds (fig. 3, section D-D'). This is one of 

the few places in the Wood River area where folds verge 

westward. 

The lower member of the Dollarhide Formation hosts most 

of the mineralized rock (Skipp and others, 1994). Fryklund 

(1950), following Umpleby and others (1930), labeled these 

rocks as Wood River Formation, though he notes, “it is possible 

that Milligen formation is also present” (p. 64). An unpublished 

map (circa 1970) of W.E. Hall labels the dark-colored rocks in 

the Bullion area as Milligen Formation. Hall (1985) showed the 

rocks as Dollarhide Formation, and Wavra and Hall (1989) 

showed them as upper member, Dollarhide Formation. 

The lower member of the Dollarhide Formation in the Bullion area contains fine- to medium-grained sandstone, black siltite and black limestone or marble. A distinctive lithology in the 

lower member is channelized disorganized conglomerate that 

contains mainly intrabasinal soft-sediment clasts of siltstone and 

sandstone. The lower member occupies both sides of Bullion 

Gulch and the central part of Red Elephant Gulch. The rocks 
13

70

70

EXPLANATION FOR FIGURES 2-7

70

40

70

Qal

Dm

Dmi

Dmt

Dmc

Dmlc

Dml

Tcd

Tcs

Kgdk

Kqd

Pdu

Pdm

Pwe

wh

Quaternary surficial deposits

Challis Volcanic Group (Eocene)

Potassium-rich dacite, latite, and trachyte lavas—Includes a 

 variety of lavas and flow breccias. Potassium-rich dacite

 dominates this unit and is strongly porphyritic containing as

 much as 30 percent phenocrysts of plagioclase and hornblende

 and lesser amounts of biotite and pyroxene; quartz and

 sanidine are rare. Proportion and amount of all phenocryst

 types vary greatly

Volcaniclastic sedimentary rock—Includes sandstone and

 mudstone; locally contains woody fragments and other

 organic debris, and cobble to boulder conglomerate

 containing clasts of granodiorite (Skipp and others, 1994)

Cretaceous intrusive rocks associated with the Idaho Batholith

Potassium-rich hornblende-biotite grandiorite—Gray,

 medium- to coarse-grained, equigranular to porphyritic

 horneblende-biotite granodiorite and granite containing

 conspicuous books of biotite. Includes the informal Hailey

 granodiorite of Schmidt (1962) and Deer Creek Stock

Quartz diorite—Brown, medium-grained, eqigranular

 pyroxene-biotite quartz diorite. Includes Croesus stock

Sun Valley Group (Lower Pennsylvanian to Middle

 Pennsylvanian)

Eagle Creek Member (Lower Permian to Middle

 Pennsylvanian)—Calcareous sandstone, sandy and silty lime-

 stone, quartz arenite, siltstone, and argillite (880-1,300 m).

 Defined by Mahoney and others (1991) to include units 3, 4, 5,

 and 6 of the Wood River Formation of Hall and others (1974)

Hailey Member (Middle Pennsylvanian)—Pebble to boulder

 conglomerate and bioclastic limestone (0-200 m). Con-

 glomerate contains clasts of argillite, chert, and fine-grained

 quartzite and interfingers with and is overlain by bioclastic and

 biostromal limestone (unit 2 of Hall and others,1974). Unit is

 revised from Hailey Conglomerate Member of Hall and

 others (1974) by Mahoney and others (1991)

Dollarhide Formation (Lower Permian to Middle Pennsylvanian)

Upper member (Lower Permian)—Dark-colored and

 carbonaceous siltstone, silty and sandy limestone, argillite,

 and minor conglomerate (more than 900 m thick)

Middle member (Lower Permian)—Light-colored, fine- to

 medium-grained calcareous sandstone, siliceous sandstone,

 sandy limestone, silty argillite, and minor conglomerate

 (300 m). Identical to sandy parts of the Eagle Creek Member,

 Wood River Formation

Milligen Formation (Devonian)

Independance (Upper? Devonian)—Light- to dark-gray and

 brown calcareous sandstone and siltstone, and siltstone in

 laminated and graded beds, green to purple shale, and black

 cleaved argillite (more than 183 m thick). Mapped only in

 Minnie Moore area

Lucky Coin Limestone (Middle? and Lower? Devonian)—

 Black and dark-gray argillaceous thin- to medium-bedded

 limestone, black argillite (as much as 244 m thick)

Lower member (Lower? Devonian)—Black and dark-gray

 cleaved argillite and phyllite; black thinly bedded chert; and

 green to purple shale (more than 48 m thick). Mapped only

 only in Minnie Moore area

Pdl Lower member (Lower Permian to Middle Pennsylvanian—

 Dark-colored and carbonaceous calcareous sandstone,

 calcareous siltstone, sandy and silty limestone and marble,

 argillite, and minor granule to boulder conglomerate (more

 than 800 m thick). In Kelly Gulch contains phyllite foliated

 quartzite, and calc-silicate schist. Conglomerate overprint

 indicates conglomerate lens

Milligen Formation, undifferentiated (Devonian)—Black,

 generally cleaved, argillite and phyllite; black, thinly bedded

 quartzite; brown to maroon, calcareous sandstone and silt-

 stone, black, carbonaceous limestone; gray sandy limestone;

 brown, finely laminated dolomite; and green to brown shales

 (more than 660 m). Near faults and fold axes the competent

 lithologies are generally well cleaved and tightly folded, where

 as component units are generally boudined

Triumph Argillite (Middle? Devonian)—Black, well-cleaved

 argillite and phyllite and black, thinly bedded chert (as much

 as 152 m). Mapped only in Minnie Moore area

Cait quartzite (Middle Devonian)—Distinctive black coarse-

 grained argillaceous sandstone (0-20 m). Unit is lenticular in

 the Triumph Argillite and in the upper part of the Lucky Coin

 Limestone. Mapped only in Minnie Moore area

Contact—Dashed where approximately located

Strike and dip of bedding with top determined

Vertical bedding

Overturned bedding with top determined

Sheared unconformity—Arrows on stratigraphically younger

 side

Thrust fault—Dashed where approximately located, dotted

 where concealed, queried where uncertain

Anticline—Showing overturn; arrows point down dip of axial

 plane

Syncline—Showing overturn; arrows point down dip of axial

 plane

Low-angle normal fault—Dashed where approximately located,

 dotted where concealed, queried where uncertain; double

 hachure on hanging wall

High-angle normal fault—Showing dip. Dashed where approx-

 imately located, dotted where concealed, queried where 

 uncertain; bar and ball on hanging wall

Fault—Showing dip of fault and trend and plunge of slickenlines

 on fault surface

Breccia

Dike

Adit; shaft

Line of cross section

Form lines showing bedding orientation in cross section

Mineralized vein—Showing dip (modified from Lindgren, 1899;

 Umpleby and others, 1930; Anderson and others, 1950).

 Some veins are named in the Mayflower, Eureka, and Minnie

 Moore areas. Some veins occupy fault zones; some are

 sheared or faulted

Mineralized fault

Structure and Metamorphism
14 Geology and Mineral Deposits, Minnie Moore and Bullion Mineralized Areas, Blaine County, Idaho

B

C

B'

C'

Qal

Qal

Qal

Qal

Pwe

Dm

Dm

Snoose

Mine

Croesus Stock

Dm

Dm

Dmi?

Dmi?

Dmi?

Dmi?

Dmt Dmt

Dmt

Dmc

Dmlc Dmlc

Dmlc Dmlc

Dmlc

Kqd

Kqd Kqd

Pwe?

Pwe?

wh? wh

wh

Pdl? Pdl?

Pdl

Dmt?

Dmt?

Dmlc?

Dml?

Dml? Dml?

Dml?

?

?

5

55

25

75

85

67

65

35

50

60

55

45

40

20

30

50

35

65

55

55

50

72

40

50

43°30' 114°17'30"

114°20'

43°30'

114°20'

Figure 2 (above and facing page). Geologic map of the Minnie Moore mineralized area, Blaine County, Idaho.

east of Bullion Gulch are mapped as being stratigraphically high 

in lower member Dollarhide Formation, because the middle 

member quartzite is not present. They are intruded on the east 

by the Deer Creek stock.

In the Bullion area the middle member of the Dollarhide 

Formation (regionally about 300 m [984 ft] thick) contains silicified sandstone that crops out as light-gray to brown quartzite that 

forms the high ridge between Red Elephant and Bullion Gulches. 

These rocks were shown as Wood River Formation on the map of 

Hall (1985). The mineralized veins of the Bullion area do not 

extend southward into the middle member Dollarhide Formation. 

The middle member, much less silicified, is also present in westdipping beds on the ridge of Kelly Mountains. 

Black shale or siltite on the west side of the Bullion area, 

west of the Kelly Mountain ridge (fig. 3), is tentatively identified 

as the upper member of the Dollarhide Formation.

Host Structures for Mineralization

Known ore deposits in the Minnie Moore and Bullion mineralized areas are localized along fault systems that formed during and after Late Cretaceous intrusion of plutons related to the 

Idaho batholith. These structural hosts include both high- to 

moderate-angle normal faults and low- to moderate-angle 

reverse faults. Veins along both types of faults are characterized 
15

0 1 MILE

0 1 KILOMETER

A

A'

Qal

Qal

Pwe

Pdl

Croesus Stock

Outside of study area

Outside of study area

Wood River half-graben

Rockwell Flat Fault?

Rockwell Flat Fault?

Minnie Moore Shaft

Queen of the Hills Vein

Minnie Moore Vein

Dmc Dmc

Dmlc

Dmlc Dmlc

Kqd

Kqd

Pdl?

Dmt?

Dmt?

Dml?

Dml?

Silver Star Queen Shaft

69

35

45

45 60

65

30

45

57

32

44

65

55

40

70

43°27'30"

43°27'30" 114°17'30"

by changes in strike and both flattening and steepening of dip. 

There is evidence for contemporaneous and post-mineralization 

movement along many structures; however, maps of the area 

(Umpleby and others, 1930; Anderson and others, 1950; Hall, 

1985; this paper) demonstrate that most of these mineralized 

fault systems or shear zones do not have mappable stratigraphic 

offset. Anderson (1950, p.11) accounted for this lack of offset 

by hypothesizing that faults along which there was significant 

movement are not mineralized either because “they contained so 

much gouge that the ore solutions could not enter or circulate 

along them, or because they are post-mineral.”

Minnie Moore Area

Mineralized veins in the Minnie Moore (fig. 1, site 77) and 

Silver Star Queens (site 78, section A-A') mines strike northwest, subparallel with bedding (fig. 2, section A-A'; fig. 4). The 

Structure and Metamorphism
16 Geology and Mineral Deposits, Minnie Moore and Bullion Mineralized Areas, Blaine County, Idaho

43°30"

114°27'30"

70

50

65

70

70

70 80

45

40 85 75

40

30

75

55

61

55

20 75

45

45

40

80

70

80

35 45

75

65

60

10

50

60

75

65

57

65

45 85 60

75

70

85

75

75

33

Qal

Qal

Tdp

Qal

Tcd

Kgdk

Pwe

Pwe

Pwe

Pdu

Pdu

Pdm

Pdm

Pdm

Pdm

Pdm

Pdm

Pdl

Pdl

Pdl

Pdl

Pdl

Pdl

Pdl

Pdl

Pdl

Pdl

Pdl

Pdl

?

?

?

?

Kelly

Mountain

D

D'

Kelly Gulch

0 1 MILE

0 1 KILOMETER

Figure 3 (above and facing page). Geologic map of the Bullion mineralized area, Blaine County, Idaho.
17

114°25'

30

54

65

53

50

75

70

75

30

55

70

80

50

35

45

57 55

65

70

75

55 45

40

32

30

75

60

45

45

85

65

65

50

72

Qal

Qal

Qal

Qal

Tcd

Tcd

Tcd

Tcs

Tcd

Kgdk

Kgdk

Kgdk

Pwe

Pdm

Pdm

Pdm

Pdl

Pdl

Pdl

Pdl

Pdl Pdl

Pdl

Pdl

Pdl

Pdl

Pdl

Pdl

Pdl

Pdl?

Pdl

?

77 70

70

75

56

D"

Bullion Gulch

Elk Creek

Red Elephant Gulch

Whale

Indian Queen

Mayflower

Mountain View

Point Lookout

Caledonia

OK

Eureka

Mud vein

Structure and Metamorphism
18 Geology and Mineral Deposits, Minnie Moore and Bullion Mineralized Areas, Blaine County, Idaho

Minnie

Fault

A A'

Rockwell

Flat

Fault

Croesus

Stock

Allen Fault

Minnie

Moore

Vein

Minnie

Moore

Gulch

Queen of the Hills- Silver Star

Queens Vein

Wood River Valley

3250

3500

3750

5000

4000

6000

7000 METERS FEET

0 1 MILE

0 1 KILOMETER

Qal

Kqd

Kqd

Kqd

Dm?

Dmt

Dmt Dmc

Dmc

Dmlc

Dmlc

Dmlc?

Dmlc

Dml?

Dml? Dml

B

Croesus

Stock

Snoose

Vein

B'

Intersection with

C-C'

Wood River

Valley

3250

3500

3750

5000

4000

6000

7000 METERS FEET

0 1 MILE

0 1 KILOMETER

Qal

Kqd

Pwe

Pwe

Pwe

wh Pdl

Dm?

Dmi?

Dmi

Dmi

Dmt

Dmt

Dmlc

Dml

Dmlc

Figure 4. Geologic cross section A–A' through the Minnie Moore and Silver Star Queens veins, 

Minnie Moore mineralized area. Location of cross section shown on figure 2.

Figure 5. Geologic cross section B–B' through the Snooze vein, Minnie Moore mineralized area. Location of cross 

section shown on figure 2.

Minnie Moore vein was the richest of these veins and varied in 

dip from 25° to 35° SW., though in places it was almost 

horizontal (Anderson, 1950). The vein was never more that 200 

ft (61 m) below the intrusive contact of the Croesus stock.

In Colorado and Star Gulches, ore is hosted by high-angle 

fracture systems (Snoose vein, fig. 1, section B-B'; fig. 5) that 

trend northwest and dip mostly southwest.

Bullion Area

Host structures for mineralized veins in the Bullion area are 

a system of almost parallel northwest-striking fractures of the 

Mayflower and Eureka fault systems, none of which have mappable separation at 1:24,000 scale (fig. 3). The Mayflower system 

strikes about N. 50° E. and dips 70°–85° to the southeast on the 

surface; underground the dip is as shallow as 30° (Anderson and 

others, 1950, p. 66). Although there are suggestions of reverse 

movement along many of the mineralized structures, the last 

movement as recorded by slickensides is either normal or horizontal. In the Bullion area some mineralized fractures or veins 

(including the Eureka vein, fig. 3, section D-D'; fig. 6) extend 

into the Deer Creek stock, but are not extensively mineralized in 

the granodiorite host rock. 

Post-Mineralization Faults

Veins in the Minnie Moore mineralized area and quartz 

diorite of the Croesus stock are cut by several “post-mineral 

faults” (Hewett, 1930, p. 234-237). The Rockwell flat fault in 

the Minnie Moore mine has top-to-the-northeast offset of about 

60 m (200 ft) (fig. 2, section A-A'; fig. 4). The northwest-striking 

Minnie oblique-slip fault cuts both the Rockwell flat fault and 

the Minnie Moore vein. The vein was not found again southeast 

of the Minnie fault, despite extensive exploration. 
19

Kelly Mountain

Kelly

Gulch (Elk Creek)

Red Elephant

Gulch

D D'

(Elk Creek)

Red Elephant

Gulch

Caledonia

Red Elephant Fault

(mud vein)

Fault Bullion Gulch

(Left Fork)

Mayflower Vein

Whale Vein

Eureka

Vein

Bullion Gulch

(Right Fork)

Deer Creek

Stock

D' D"

3250

3500

3750

4000

4250

5000

4000

6000

7000

8000

METERS FEET

3250

3500

3750

4000

4250

5000

4000

6000

7000

8000

METERS FEET

0 1 MILE

0 1 KILOMETER

Qal

Qal Pdu Pdm

Pdm

Pdl

Pdl

Pdl

Pdl

Pdl

Dm?

Dm? Dm?

Qal

Qal

Kgdk

Kgdk

Pdl

Pdl

Pdl

Dm?

Dm? Dm?

A major low-angle top-to-the-northwest normal fault terminates the mineralized veins north of Star Gulch (fig. 1, section 

C–C′; fig. 7)).

Mineral Deposits

Classification

Most ore deposits in the Minnie Moore and Bullion areas 

are in typical “Wood River-type” galena, sphalerite, tetrahedrite veins that have a siderite gangue (Lindgren, 1933; Hall 

and others, 1978). They are classified as polymetallic vein and 

replacement deposits by Worl and Johnson (1995) and consist 

of polymetallic fissure filling and replacement veins hosted by 

rocks of the Milligen and Dollarhide Formations (black shale 

terrane of Worl and Johnson, 1995). Replacement of sheared 

and broken host rock was the main mechanism for ore formation (Umpleby and others, 1930, p. 91). The replacement orebodies are generally aligned along fault zones. The orebodies 

are sharply defined lenses or shoots of varying size and distribution; the fracture systems otherwise show little evidence of mineralization or hydrothermal alteration. Gold-bearing 

polymetallic quartz vein and lode deposits (Worl and Johnson, 

1995) characterized by quartz, pyrite, chalcopyrite and arsenopyrite are also present in the Minnie Moore area. These are 

most common in the intrusive rocks of the Idaho batholith 

(Croesus stock and the informal Hailey granodiorite of 

Schmidt, 1962) just to the west of the Minnie Moore area (fig. 

1) (Worl and Lewis, in press). Where both types are present, 

commonly in the same structure, the polymetallic (siderite-leadsilver) veins are younger than the gold-bearing quart veins and 

lodes (Anderson and others, 1950, p.10). 

Mineral Deposits

Figure 6. Geologic cross section D–D’–D” through the Red Elephant, Mayflower, Eureka, and Whale veins, Bullion mineralized 

area. Location of cross section shown on figure 3.
20 Geology and Mineral Deposits, Minnie Moore and Bullion Mineralized Areas, Blaine County, Idaho

Croy

Creek

C

Colorado

Gulch

Intersection with

B-B'

C'

Star

Gulch

3250

3500

3750

5000

4000

6000

7000

METERS FEET

0 1 MILE

0 1 KILOMETER

Qal Qal

Qal

Dm

Dmlc

Dmlc?

Dml?

Mineralogy

The ore in both the Minnie Moore and Bullion areas is 

characterized by uniform mineralogy and texture throughout the 

individual bodies and throughout the two mineralized areas. 

Generally the deposits contain galena, sphalerite, and tetrahedrite as the principal ore minerals and siderite as the principal 

gangue mineral. Other minerals commonly present include 

chalcopyrite, pyrite, arsenopyrite, quartz, and calcite. In the 

Minnie Moore area siderite is “clearly closely associated with 

the ore mineralization” (Anderson and others, 1950, p. 71). 

Crushed wallrock is commonly a major portion of the gangue.

The ore at the Minnie Moore mine (fig. 1, site 77) consists 

of galena, pyrite, sphalerite, gray copper, chalcopyrite, and arsenopyrite in a gangue of siderite, quartz, calcite, and crushed 

country rock (Anderson, 1950). The ore at the Silver Star 

Queens mine (site 78) consists of sphalerite, galena, tetrahedrite, 

pyrite and marcasite in a gangue of quartz, siderite, and calcite.

Isotopic, Age, and Fluid Inclusion Data

Ore in the Minnie Moore and Bullion areas is mesothermal 

and is associated with the Late Cretaceous Croesus and Deer 

Creek stocks. The ore occupies northwest-striking faults and 

fracture systems, a few of which cut the nearby intrusive rocks. 

Maximum ages for the veins are given by the adjacent stocks. 

The Deer Creek stock has been dated at 90.4±0.2 Ma and 

94.4±0.3 Ma on biotite and hornblende, respectively, using the 

40Ar-39Ar method (L.W. Snee, written commun., 1991). The 

Croesus stock is older than the intruding 84-Ma Hailey granodiorite (Worl and Lewis, in press).

Fluid inclusion from ore in several mines have homogenization temperatures of 244°–307°C, and freezing-stage measurements suggest salinities of 3.2–4.8 weight percent NaCl (Hall 

and others, 1978). 

Sulfur isotope studies from sulfide minerals suggest a shallow crustal source (Hall and others, 1978; Howe and Hall, 

1985). Lead isotope ratios of galena from the polymetallic veins 

suggest an ultimate lead source from buried Precambrian crust 

(Sanford and Wooden, 1995), either directly from batholithdriven hydrothermal convection cells or from remobilization of 

lead concentrated in syngenetic deposits in the Dollarhide and 

Milligen Formations and which originally came from a 

Precambrian source.

Description of Orebodies

The Minnie Moore orebody is a gently inclined blanket 

like body 365 m (1200 ft) long and as wide as 5.5 m (18 ft). 

Before mining, the orebody was made up of irregular lenses of 

sulfides that were followed by individual stopes within the 

mine. The ore bodies consisted of three zones, mainly siderite 

on the west and calcite on the east and an intermediate zone 

between. The minable ore was confined to the middle and 

eastern zones. 

The ore zone at the Silver Star Queens mine occupied 

veins striking northwest and dipping southwest. The principal 

ore shoot had a stope length of almost 152 m (500 ft) and was 

made up of sulfide lenses as thick as 2 m (6 ft) (Anderson, 

1950). 

The vein in the Snoose mine (fig. 1, site 71) strikes northwest and dips 50° NE. (Anderson, 1950, p. 23). The ore contains sphalerite and galena with abundant pyrite.

Orebodies in the Bullion area (Mayflower and Red 

Elephant mine areas, fig. 1, sites 14 and 13) are gouge-filled 

fractures along the Mayflower fault zone. 

Alteration

Generally, ore minerals in both the Minnie Moore and 

Bullion area are hosted by fresh black argillite and limestone. There is no pervasive alteration pattern or guide to 

location of ore minerals. The rock along the mineralized 

fissures shows some bleaching with formation of sericite, 

carbonate, and pyrite. 

Figure 7. Geologic cross C–C ’ section through Colorado Gulch and Star Gulch, Minnie Moore mineralized area. Location of cross section 

shown on figure 2.
21

Supergene enrichment was not important in the Wood 

River area (Umpleby and others, 1930, p. 110), and the maximum depth of oxidation was about 15m (50 ft). At the surface 

some veins are oxidized to iron and manganese oxides and 

intermixed lead and zinc carbonates and sulfates.

Genesis and Ore Controls

The orebodies of the Minnie Moore and Bullion areas 

formed during faulting that occurred shortly after Late Cretaceous magmatic activity (Hall and others, 1978). This is demonstrated by the fact that the orebodies occupy post-intrusive 

rocks.

The Minnie Moore orebodies are in the middle part of the 

Milligen Formation. They are hosted by the Lucky Coin limestone and the Triumph argillite. The orebodies are in close 

proximity to tongues of sand in the Cait quartzite, which is the 

same stratigraphic position as the ore in the Triumph area. The 

metals may have been remobilized from primary stratiform 

syngenetic deposits, as suggested regionally by Hall (1985), 

Howe and Hall (1985) and for the Triumph area by Turner and 

Otto (1995).

The source of the ore metals in the Bullion area is uncertain. Wavra and Hall (1989) suggested that syngenetic stratiform mineralized rock is in the upper member of the Dollarhide 

Formation and that the Mayflower vein could be remobilized 

from it. We map these rocks, however, as lower member, Dollarhide Formation, but do not discount syngenetic stratiform 

mineralization. Another option is that the ore is remobilized 

from Milligen Formation that unconformably underlies the 

Dollarhide Formation at shallow depths in the Bullion area. 

The polymetallic veins represent one end member of a family of veins and replacement deposits that formed during the late 

stages of formation of the Idaho batholith. The other end member is represented by gold-quartz veins (polymetallic quartz 

veins and lodes) (Worl and Johnson, 1995). The polymetallic 

quartz veins and lodes are hosted mainly by plutonic rocks; 

examples are the Croesus mine and in the Hailey Gold Belt 

(Worl and Lewis, in press).

Exploration Guides

Although stratigraphic location of the host rock is different 

in the Minnie Moore and Bullion areas, the ore deposits are of 

similar types and are hosted by similar dark-gray to black argillite and limestone. Syngenetic stratiform exploration models 

predict that stratabound silver-lead-zinc deposits are present in 

both the Minnie Moore and Bullion areas (see Hall, 1985; Wavra 

and others, 1986; Wavra and Hall, 1989); however the mined 

structures are fault-zone hosted veins, and no syngenetic model 

has not been extensively tested in exploration efforts in the area. 

Post-mineralization faulting is a major concern. 

Discovery of new vein deposits similar to those already 

mined, that is, veins along northwest- striking faults, is unlikely 

because the faults have been extensively prospected. However, 

because the veins are cut by low-angle faults, they may be 

relocated across these faults, as suggested by Anderson (1950) 

for the Minnie Moore area.

References

Anderson, A.L., 1950, Geology and ore deposits of the Hailey-Bellevue 

mineral belt, in Anderson, A.L., Kiilsgaard, T.H., and Fryklund, V.C., 

Jr., 1950, Detailed geology of certain areas in the Mineral Hill and 

Warm Springs mining districts, Blain County, Idaho: Idaho Bureau of 

Mines and Geology Pamphlet 90, p. 1–37.

Anderson, A.L., Kiilsgaard, T.H., and Frylund, V.C., Jr., 1950, Detailed 

geology of certain areas in the Mineral Hill and Warm Springs 

mining districts, Blain County, Idaho: Idaho Bureau of Mines and 

Geology Pamphlet 90, 73 p.

Burton, B.R., and Link, P.K., 1995, Structural setting of ore deposits in the 

Lake Creek mineralized area, Blain County, south-central Idaho: U.S. 

Geological Survey Bulletin 2064-F, 15 p. 

Burton, B.R., Link, P.K., and Rodgers, D.W., 1989, Death of the Wood River 

thrust—Structural relations in the Pioneer and Boulder Mountains, 

south-central Idaho: Geological Society of America Abstracts with 

Programs, v. 21, no. 5, p. 62.

Fryklund, V.C., Jr., 1950, The ore deposits of the Mayflower area, in

Anderson, A.L., Kiilsgaard, T.H., and Fryklund, V.C., Jr., Detailed 

geology of certain areas in the Mineral Hill and Warm Springs mining districts, Blaine County, Idaho: Idaho Bureau of Mines and Geology Pamphlet 90, p. 63–73.

Hall, W.E., 1985, Stratigraphy and mineral deposits in middle and upper 

Paleozoic rocks of black-shale mineral belt, central Idaho, in McIntyre, D.H., ed., Symposium on the geology and mineral resources of 

the Challis 1°×2° quadrangle, Idaho: U.S. Geological Survey Bulletin 

1658-J, p. 117–132.

Hall, W.E., and Czamanske, G.K., 1972, Mineralogy and trace-element 

content of the Wood River lead-silver deposits, Blaine County, Idaho: Economic Geology, v. 67, p. 350–361.

Hall, W.E., Batchelder, J.H., and Douglass, R.D., 1974, Stratigraphic section of the Wood River Formation, Blaine County, Idaho: U.S. Geological Survey Journal of Research, v. 6, no. 5, p. 579–592.

Hall, W.E., Rye, R.O., and Doe, B.R., 1978, Wood River mining district—

Intrusion related lead-silver deposits derived from country rock 

source: U.S. Geological Survey Journal of Research, v. 6, no. 5, p. 

579–592. 

Hewett, D.F., 1930, Geology of the Minnie Moore and near-by mines, 

Mineral Hall mining district, Blain County, Idaho: U.S. Geological 

Survey Bulletin 814, p. 209–245.

Howe, S.S., and Hall, W.E., 1985, Light stable isotope characteristics 

of ore systems in central Idaho, in McIntyre, D.H., ed., Symposium on the geology and mineral resources of the Challis 1°×2°

quadrangle, Idaho: U.S. Geological Survey Bulletin 1658-P, p. 

183–192. 

Hustedde, G.S., Copeland, J.A., Strowd, W.B., Mitchell, V.E., and Bennett, 

E.H., 1981, Mines and prospects of the Hailey quadrangle, Idaho: 

Idaho Bureau of Mines and Geology mines and Prospects map 

series, scale 1:250,000, 41 p.

Lindgren, W., 1900, The gold and silver veins of Silver City DeLamar, and 

other mining districts in Idaho: U.S. Geological Survey 20th Annual 

Report, pt. 3, p. 65–256.

References
22 Geology and Mineral Deposits, Minnie Moore and Bullion Mineralized Areas, Blaine County, Idaho

Lindgren, W., 1933, Mineral deposits (4th ed.): New York, McGraw-Hill, 

930 p.

Link, P.K., Skipp, Betty, Hait, M.H., Janecke, Susanne, and Burton, B.R., 

1988, Structural and stratigraphic transect of south-central Idaho—A field guide to the Lost River, White Knob, Pioneer and 

Smoky Mountains, in Link, P.K. and Hackett, W.R., eds., Guidebook 

to the geology of central and southern Idaho: Idaho Geological Survey Bulletin 27, P. 5–42.

Link, P.K., Mahoney, J.B., Bruner, D.J., Batatian, L.D., and William, 

F.J.C., 1995, Stratigraphic setting of sediment-hosted mineral 

deposits in the eastern part of the Hailey 1°×2° quadrangle and 

part of the southern part of the Challis 1°×2° quadrangle, southcentral Idaho: U.S. Geological Survey Bulletin 2064-C, 33 p.

Mahoney, J.B., Link, P.K., Burton, B.R., Geslin, J.G., and O’Brien, J.P., 

1991, Pennsylvanian and Permian Sun Valley Group, Wood River 

Basin, south-central Idaho, in Cooper, J.D., and Stecens, C.H., eds., 

Paleozoic paleogeography of the Western United States—II: Los 

Angeles, Pacific Section Society of Economic Paleontologists and 

Mineralogists Publication 67, v. 2, p. 551–579.

Rodgers, D.W., Link, P.K., and Huerta, A.D., 1995, Structural framework 

of mineral deposits hosted by Paleozoic rocks in the northeastern 

part of the Hailey 1°×2° quadrangle, south-central Idaho: U.S. Geological Survey Bulletin 2064-B, 18 p.

Sanford, R.F., and Wooden, J.L., 1995, Sources of lead in ore deposits in 

central Idaho: U.S. Geological Survey Bulletin 2064-N, 24 p.

Schmidt, D.L., 1962, Quaternary geology of the Bellevue area in Blaine 

and Cama Counties, Idaho: U.S. Geological Survey Open-File 

Report 62-0120, 135 p., scale 1:48,000.

Skipp, Betty, Hall, W.E., and Link, P.K., 1994, Geologic map of the 

Mahoney Butte quadrangle, Blaine County, Idaho: U.S. Geological 

Survey Geologic Quadrangle Map GQ-1742, scale 1:24,000.

Turner, R.J.W., and Otto, B.R., 1988, Stratigraphy and structure of the 

Milligen Formation, Sun Valley area, Idaho, in Link, P.K., and Hackett, W.R., eds., Guidebook to the geology of central and southern 

Idaho: Idaho Geological Survey Bulletin 27, p.153–167.

Turner, R.J.W. and Otto, B.R., 1995, Structural and stratigraphic setting 

of Triumph stratiform zinc-lead-silver deposits, Devonian Milligen 

Formation, central Idaho: U.S. Geological Survey Bulletin 2064-E, 

27 p.

Umpleby, J.B., Westgate, L.G., and Ross, C.P., 1930, Geology and ore 

deposits of the Wood River region, Idaho: U.S. Geological Survey 

Bulletin 27, p. 153–167.

Wavra, C.S., and Hall, W.E., 1989, Potential for shale-hosted massive 

sulfides in the Permian Dollarhide Formation, south-central Idaho: 

U.S. Geological Survey Open-File Report 88-376: 9 p.

Wavra, C.S., Isaacson, P.E., and Hall, W.E., 1986, Studies of the Idaho 

black shale belt—Stratigraphy, depositional environment, and 

economic geology of the Permian Dollarhide Formation: Geological 

Society of America Bulletin, v. 97, p. 1594–1511.

Worl, R.G., and Johnson, K.M., 1995, Geology and mineral deposits of 

the Hailey 1°×2° quadrangle and western Idaho Falls 1°×2° quadrangle, south-central Idaho—An overview: U.S. Geological Survey 

Bulletin 2064-A, 21 p.

Worl, R. G., and Lewis, R. S., in press, Vein deposits hosted by plutonic 

rocks in the Croesus stock and Hailey gold belt mineralized areas, 

Blaine County, Idaho: U. S. Geological Survey Bulletin 2064-X.