Esperanza Mine

The Esperanza Mine is a silver and gold mine located in Saguache county, Colorado at an elevation of 9,409 feet.

About the MRDS Data:

All mine locations were obtained from the USGS Mineral Resources Data System. The locations and other information in this database have not been verified for accuracy. It should be assumed that all mines are on private property.

Mine Info

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Site Name

Primary: Esperanza Mine
Secondary: Esperanza
Secondary: Valardena
Secondary: Jesus Marie

Commodity

Primary: Silver
Primary: Gold
Tertiary: Manganese
Tertiary: Copper
Tertiary: Zinc
Tertiary: Lead

Location

State: Colorado
County: Saguache
District: Crystall Hill District

Land Status

Land ownership: Private
Note: the land ownership field only identifies whether the area the mine is in is generally on public lands like Forest Service or BLM land, or if it is in an area that is generally private property. It does not definitively identify property status, nor does it indicate claim status or whether an area is open to prospecting. Always respect private property.

Holdings

Not available

Workings

Type: Underground

Ownership

Owner Name: J. Nichol
Home Office: San Francisco, Ca.
Years: 1928 -

Owner Name: George W. Altman
Home Office: Denver, Co.
Years: 1928 -

Production

Not available

Deposit

Record Type: Site
Operation Category: Past Producer
Operation Type: Unknown
Year Last Production: 1920
Discovery Year: 1884
Years of Production:
Organization:
Significant: N
Deposit Size: S

Physiography

General Physiographic Area: Rocky Mountain System
Physiographic Province: Southern Rocky Mountains

Mineral Deposit Model

Not available

Orebody

Not available

Structure

Type: R
Description: San Juan Volcanic Field, Rio Grande Rift

Type: L
Description: Biedell-Klondike Fault, Esperanza Fault Zone, Biedell Stock

Alterations

Alteration Type: L
Alteration Text: Pervasive Propylitization; Locally Intense Argillization; Kaolinitization, Silicification

Rocks

Name: Quartz Latite
Role: Associated
Age Type: Host Rock Unit
Age Young: Oligocene

Name: Quartz Latite
Role: Associated
Age Type: Associated Rock
Age Young: Oligocene

Name: Quartz Latite
Role: Associated
Age Type: Associated Rock Unit
Age Young: Oligocene

Name: Quartz Latite
Role: Associated
Age Type: Host Rock
Age Young: Oligocene

Analytical Data

Analytical Data: TWO ORE SAMPLES FROM 100 LEVEL ASSAYED 0.04 OZ/TON AU AND 20.8 OZ/TON AG. SIX SAMPLES FROM FACE, FLOOR, AND BREAST ON 200 LEVEL AVERAGED 0.032 OZ/TON AU AND 25.05 OZ/TON AG, RANGING 0.02 TO 0.05 OZ/TON AU AND 5.6 TO 38.2 OZ/TON AG. TWO SAMPLES FROM WINZE BELOW 200 LEVEL ASSAYED 0.05 AND 0.06 OZ/TON AU, 21.3 AND 23.3 OZ/TON AG. COMPOSITE ANALYSIS OF THESE TEN SAMPLES ASSAYED 67.6% SILICA, 11.1% MN, 1.8% LIME, 0.5% ZN, 0.3% S, NO PB, NO CU. ASARCO SMELTER IN PUEBLO (CIRCA 1921) REPORTED FOLLOWING WEIGHTED AVERAGE ASSAY ON NINE ORE LOTS TOTALLING 225,697 NEW LB: 0.158 OZ/TON AU AND 54.17 OZ/TON AG, WITH RANGES OF 0.12 TO 0.965 OZ/TON AU, 45.3 TO 332.8 OZ/TON AG. OSTERWALD'S GEOCHEMICAL ANALYSES SHOW 500 TO 5000 PPM CU, 500 TO 5000 PPM ZN, GT 10000 PPM PB, GT 10000 PPM AG, 20 TO 59 PPM MO

Materials

Ore: Gold
Ore: Cerargyrite
Ore: Wad
Gangue: Magnetite
Gangue: Quartz
Gangue: Malachite
Gangue: Beidellite

Comments

Comment (Location): ON CRYSTAL HILL, BETWEEN SANDERSON GULCH AND BIEDELL CREEK 8 MILES NW OF LA GARITA ; INFO FROM LAND.ST :1977

Comment (Deposit): BIEDELL STOCK IS PORPHYRITIC QUARTZ LATITE INTRUSIVE BOUNDED ON SE BY BIEDELL-KLONDIKE FAULT AND CUT BY SMALLER NORMAL FAULTS ON SW AND ON NORTH BY EAST-WEST-TRENDING ESPERANZA FAULT ZONE. OXIDIZED MANGANIFEROUS ORES FILL VOID SPACES IN BRECCIA PIPE; SOME VEIN-TYPE OCCURRENCE MAY BE PRESENT IN FAULT ZONE. MINERALIZING FLUIDS PROBABLY ORIGINATED FROM BIEDELL-KLONDIKE FAULT. SILVER HALOID AND FREE GOLD IN MANGANESE IS CONSIDERED TO BE A COCKADE ORE IN THE OXIDIZED AND LEACHED ZONE. PRESENCE OF CU CARBONATES SUGGESTS SULFIDE ZONE AND ENRICHMENT MAY LIE BELOW THE DEEPEST WORKINGS.

Comment (Workings): 200-FT SHAFT FROM WHICH 35 FT OF DRIFT AND STOPES DEVELOPED AT 100 LEVEL. ON 200 LEVEL, 20-FT CROSSCUT DRIVEN TO VEIN ALONG WHICH 215-FT DRIFT DRIVEN SW. HALFWAY DOWN 50-FT WINZE SUNK FROM THIS LEVEL IS A 25-FT INCLINE

Comment (Production): USGS MINERAL RESOURCES OF US REPORTS ESPERANZA MINE PRODUCING IN 1907, 1916, 1917, AND 1920. COLORADO DIV. MINES REPORTS 1920 PRODUCTION OF 270 TONS OF ORE CONTAINING 0.08 OZ/TON AU, 33 OZ/TON AG, 14% MN

References

Reference (Deposit): COE, H.S., 1922, ON RECONNAISSANCE EXAMINATION OF THE ESPERANZA MINE, SAGUACHE MINE, SAGUACHE COUNTY, COLORADO: COLORADO DIV. MINES UNPUB. ENG. REPT.

Reference (Deposit): NICKEL, G.D., 1922, DESCRIPTION OF ESPERANZA MINE: UNPUB. REPT. IN COLORADO DIV. MINES FILES

Reference (Deposit): LARSEN, E.S., JR., AND CROSS, WHITMAN, 1956, GEOLOGY AND PETROLOGY OF THE SAN JUAN REGION, SOUTHWESTERN COLORADO: USGS PROF. PAPER 258, P. 83-86.

Reference (Deposit): OSTERWALD, E.J., 1977, THE BEIDELL AND SANDERSON VOLCANIC CENTERS, SAGUACHE COUNTY, COLORADO: COLORADO STATE UNIV. M.S. THESIS, 145 P.

Colorado Mining Photos

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