Bootstrap/Capstone Mine (Antimony Pete Mine; Antimony Ike Mine), Bootstrap Mining District, Elko Co., Nevada, USAi
|Regional Level Types|
|Bootstrap/Capstone Mine (Antimony Pete Mine; Antimony Ike Mine)||Mine|
|Bootstrap Mining District||Mining District|
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Latitude & Longitude (WGS84):
41° 1' 7'' North , 116° 25' 0'' West
Latitude & Longitude (decimal):
Köppen climate type:
Structure: Roberts Mountains Thrust Fault A complex fault zone is exposed along the crest of the Bootstrap window. Steep north trending faults have been intruded by dikes.
Alteration: Host rocks have been affected by pervasive hydrothermal alteration: sericitization, silicification, and argillization. Dikes are sericitized. Within carbonate sediments, cherty replacement silicification along faults and joints diminishes laterally in intensity and grades into argillic alteration. Argillized zones grade into fresh country rock.
Commodity: Ore Materials: gold Gangue Materials: clay, quartz, carbonate
Deposit: Disseminated gold mineralization occurs along a NNE-trending , west-dipping fault zone over two miles long. Ore is localized on a north-striking, high angle fault developed along a competency contrast between massive Devonian Bootstrap carbonates and platform-slope talus debris within the Bootstrap Limestone. West-dipping, late Cretaceous to Tertiary dikes intruded along the fault. Later tectonism accentuated initial structural breaks, enhancing permeability and porosity.Gold occurs as microscopic particles along fractures in quartz latite and dacite dikes, chert, siliceous mudstone, calcareous siltstone, and shale.Host rocks have been affected by sericitization, silicification, and argillization. Dikes are sericitized. Within carbonate sediments, cherty replacement silicification along faults and joints diminishes laterally in intensity and grades into argillic alteration. Argillized zones grade into fresh country rock. Where several dikes are closely spaced, the ore is mineable by open pit methods.
Deposit type: Sediment-hosted Au
Development: The first reported gold production from the Bootstrap deposit was in 1914 from a small underground operation near the NW corner of the present Bootstrap pit. In 1918, approximately 500 tons of stibnite ore were shipped to the railhead at Dunphy, NV. Gold production resumed in 1958 when Harry Treweek and Marion Fischer began mining a small dike immediately west of the present Bootstrap pit. It was the largest gold producer in Elko County in 1958. In 1967, the property was acquired by Newmont, who completed a development drilling program of 76 holes totalling 4,394 meters in 1969. Newmont began mining in 1974, producing 20,000 oz. gold over the next five years by milling and heap leaching. Intermittent mining of high grade zones continued from 1976-1984, produciing an additional 100,000 oz. gold. It was listed as an active open pit mine employing 2 persons in 1980. Capstone was discovered in 1985 by Newmont and heap-leaching of low grade ore continued in 1987. Additional exploration resulted in the discovery of Tara in 1990. The property was inactive in 1991. Production resumed in 1992 with the opening of the contiguous Capstone deposit, and mining began at the Tara deposit in 1997.
Geology: The Bootstrap deposits are aligned along the crest of a N-S-trending horst block, comprised primarily of carbonate rocks of the Devonian Popovich Formation and Siluro-Devonian Roberts Mountains Formation, and siliciclastic rocks of the Devonian Rodeo Creek unit. Within the horst block, rock strata are folded into a broad, S20E-trending gently plunging antiform. Resistant carbonate units and silicified rocks forming the east limb of the antiform form a 2-mile-long, 3000-foot wide, 600-foot high ridge known as the Bootstrap Window. Most of the west limb of the antiform has been down-droped by faults and is only exposed on the west side of the Tara deposit. Dikes are up to 15' wide. Gold occurs as microscopic particles along fractures in the dikes, and in the cherts & shales. Limestone in contact with the dike is hornfelsed and partially marbleized
Ore(s): Ore is localized on a north-striking, high angle fault developed along a competency contrast between massive Devonian Bootstrap carbonates and platform-slope talus debris within the Bootstrap Llimestone. West-dipping, late Cretaceous to Tertiary dikes intruded along the fault. Later tectonism accentuated initial structural breaks, enhancing permeability and porosity. Mineralization is strongly controlled by strata (particularly at Tara) however the dominant control is structural.
Select Mineral List TypeStandard Detailed Strunz Dana Chemical Elements
Commodity ListThis is a list of exploitable or exploited mineral commodities recorded at this locality.
5 valid minerals.
Rock Types Recorded
Note: this is a very new system on mindat.org and data is currently VERY limited. Please bear with us while we work towards adding this information!
Select Rock List TypeAlphabetical List Tree Diagram
Entries shown in red are rocks recorded for this region.
Detailed Mineral List:
| ⓘ Baryte|
Reference: NBMG Spec. Pub. 31 Minerals of Nevada
| ⓘ Calcite|
Reference: NBMG Spec. Pub. 31 Minerals of Nevada
| ⓘ Gold|
Reference: NBMG Bull 106 Geology and Mineral Resources of Elko County, Nevada; U.S. Geological Survey (2005) Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia.
| ⓘ Quartz|
Reference: NBMG Spec. Pub. 31 Minerals of Nevada; U.S. Geological Survey (2005) Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia.
| ⓘ Stibnite|
Reference: NBMG Bull 106 Geology and Mineral Resources of Elko County, Nevada
List of minerals arranged by Strunz 10th Edition classification
|Group 1 - Elements|
|Group 2 - Sulphides and Sulfosalts|
|Group 4 - Oxides and Hydroxides|
|Group 5 - Nitrates and Carbonates|
|Group 7 - Sulphates, Chromates, Molybdates and Tungstates|
List of minerals arranged by Dana 8th Edition classification
|Group 1 - NATIVE ELEMENTS AND ALLOYS|
|Metals, other than the Platinum Group|
|Group 2 - SULFIDES|
|AmBnXp, with (m+n):p = 2:3|
|Group 14 - ANHYDROUS NORMAL CARBONATES|
|Group 28 - ANHYDROUS ACID AND NORMAL SULFATES|
|Group 75 - TECTOSILICATES Si Tetrahedral Frameworks|
|Si Tetrahedral Frameworks - SiO2 with  coordinated Si|
List of minerals for each chemical element
Sort byYear (asc) Year (desc) Author (A-Z) Author (Z-A)
Bonham, H.F., (1986), Bulk-Mineable Precious-Metal Deposits and Prospects In Nevada, NBMG Map 91.
NBMG, (1987), The Nevada Mineral Industry 1986, NBMG Special Publication MI-1986
MacLeod, R. (1987) Geology of the Bootstrap mine. In: Symp. Bulk Mineable, Guidebook for Field Trips; ed. Johnson, J.L. Geol. Soc. of Nevada, Reno, NV, USA, 283–284.
Baker, E.D., (1991), Geology and Ore Deposits of the Bootstrap Subdistrict, Elko County, Nevada, in Geology And Ore Deposits of the Great Basin, Raines, G.L., et al., eds., the Geological Society of Nevada, Reno, p. 619-623.
NBMG, (1991), The Nevada Mineral Industry 1990, NBMG Special Publication MI-1990.
Newmont Gold (1985) SEC Form 10K
Geology and Ore Deposits of Northeastern Nevada; Geological Society of Nevada, (1997) Spring Field Trip Guidebook, Special Publication No. 25, p. 55.
Long, K.R., DeYoung, J.H., Jr., and Ludington, S.D., (1998), Significant deposits of gold, silver, copper, lead, and zinc in the United States: U.S. Geological Survey Open-File Report 90-206A, 33 p.; 98-206B. one 3.5 inch diskette.
|USGS MRDS Record:||10310520|
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