Mastadon Mine

The Mastadon Mine is a silver mine located in La Plata county, Colorado at an elevation of 8,589 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

Satelite View

MRDS mine locations are often very general, and in some cases are incorrect. Some mine remains have been covered or removed by modern industrial activity or by development of things like housing. The satellite view offers a quick glimpse as to whether the MRDS location corresponds to visible mine remains.

Site Name

Primary: Mastadon Mine
Secondary: Patented Claims: Golden Cross No. 1, MS 14152
Secondary: Golden Needle, MS 14152
Secondary: Air Line, MS 14152
Secondary: Golden Slipper No. 1, MS 14152
Secondary: Golden Slipper No. 2, MS 14152
Secondary: Patented Claims: Golden Cross No. 1, MS 14152a
Secondary: Golden Needle, MS 14152a
Secondary: Air Line, MS 14152a
Secondary: Golden Slipper No. 1, MS 14152a
Secondary: Golden Slipper No. 2, MS 14152a
Secondary: Golden Cross Mill Site, MS 14152b
Secondary: Green River, MS 15230
Secondary: Grand View, MS 15230
Secondary: Tip Top, MS 15230
Secondary: American, MS 15231
Secondary: Sideline, MS 15231
Secondary: Washington, MS 15231
Secondary: Crown, MS 15231

Commodity

Primary: Silver
Secondary: Lead
Secondary: Gold

Location

State: Colorado
County: La Plata
District: Needle Mountain (Tacoma, Florida, Vallecito) District

Land Status

Land ownership: National Forest
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.
Administrative Organization: San Juan N. F.

Holdings

Not available

Workings

Not available

Ownership

Not available

Production

Not available

Deposit

Record Type: Site
Operation Category: Occurrence
Deposit Type: Vein
Operation Type: Unknown
Discovery Year: 1900
Discovery Method: Ore-Mineral In Place
Years of Production:
Organization:
Significant: N
Deposit Size: S

Physiography

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

Mineral Deposit Model

Model Name: Polymetallic veins

Orebody

Not available

Structure

Type: R
Description: San Juan Uplift, San Juan Basin, San Juan Volcanic Field

Type: L
Description: Needle Mtns Uplift, Eolus Batholith, Chicago Basin Stock, Trimble Stock

Alterations

Not available

Rocks

Name: Rhyolite
Role: Associated
Age Type: Associated Rock Unit
Age in Years: 9.000000+-0.900000
Material Analyzed: Zircon
Age Young: Miocene

Name: Rhyolite
Role: Associated
Age Type: Associated Rock Unit
Age in Years: 10.100000+-1.100000
Material Analyzed: Zircon
Age Young: Miocene

Name: Quartz Monzonite
Role: Associated
Age Type: Host Rock Unit
Age in Years: 1466.000000+-27.000000
Dating Method: Rb-Sr
Age Young: Precambrian

Name: Quartz Monzonite
Role: Associated
Age Type: Host Rock Unit
Age in Years: 1466.000000+-20.000000
Dating Method: U-Pb (zircon)
Material Analyzed: Zircon
Age Young: Precambrian

Name: Quartz Monzonite
Role: Associated
Age Type: Host Rock Unit
Age in Years: 1460.000000+-70.000000
Dating Method: K-Ar
Age Young: Precambrian

Name: Quartz Monzonite
Role: Associated
Age Type: Associated Rock Unit
Age in Years: 9.000000+-0.900000
Material Analyzed: Zircon
Age Young: Miocene

Name: Quartz Monzonite
Role: Associated
Age Type: Associated Rock Unit
Age in Years: 10.100000+-1.100000
Material Analyzed: Zircon
Age Young: Miocene

Name: Granite
Role: Associated
Age Type: Associated Rock Unit
Age in Years: 1466.000000+-27.000000
Dating Method: Rb-Sr
Age Young: Precambrian

Name: Granite
Role: Associated
Age Type: Associated Rock Unit
Age in Years: 10.100000+-1.100000
Material Analyzed: Zircon
Age Young: Miocene

Name: Granite
Role: Associated
Age Type: Associated Rock Unit
Age in Years: 1466.000000+-20.000000
Dating Method: U-Pb (zircon)
Material Analyzed: Zircon
Age Young: Precambrian

Name: Granite
Role: Associated
Age Type: Associated Rock Unit
Age in Years: 1460.000000+-70.000000
Dating Method: K-Ar
Age Young: Precambrian

Name: Granite
Role: Associated
Age Type: Associated Rock Unit
Age in Years: 9.000000+-0.900000
Material Analyzed: Zircon
Age Young: Miocene

Analytical Data

Analytical Data: SCOTT'S (1983) FIRE ASSAYS OF SAMPLES FROM SHAFT, PROSPECTS, AND THREE TUNNELS: 0.3 OZ/TON AG FROM SHAFT DUMP, 0.3 OZ/TON AG FROM DUMP OF LOWER PROSPECT PIT, 0.2 TO 0.4 OZ/TON AG FROM CHIP SAMPLES OF VEIN MATERIAL IN LOWER TUNNEL, 0.2 TO 0.4 OZ/TON AG FROM CHIP SAMPLES OF GOLDEN CROSS VEIN IN MIDDLE TUNNEL, 0.5 OZ/TON AG FROM CHIP SAMPLES FROM GOLDEN SLIPPER VEIN SECOND TUNNEL, 0.2 TO 0.3 OZ/TON AG FROM CHIP SAMPLES OF GOLDEN CROSS VEIN IN UPPER TUNNEL, 0.3 TO 0.4 OZ/TON AG FROM CHIP SAMPLES OF GOLDEN SLIPPER VEIN IN UPPER TUNNEL, DUMP SAMPLE FROM UPPER TUNNEL CONTAINED 0.3 OZ/TON AG, 0.026 OZ/TON AU.

Materials

Gangue: Limonite
Gangue: Quartz
Gangue: Chlorite

Comments

Comment (Location): (LAND STATUS AND ADMINISTRATIVE AREA LOCATIONS CALCULATED USING GIS OVERLAY ANALYSIS FOR SAN JUAN N. F.). ALONG LOWER NEEDLE CREEK AND UNNAMED TRIBUTARY APPROX ONE MILE SE OF CONFLUENCE WITH ANIMAS RIVER. ELEV AND LAT-LONG GIVEN ARE FOR LOWER ADIT ON NEEDLE CREEK. ; INFO FROM LAND.ST :1974

Comment (Workings): SURFACE PROSPECTS; LOWER TUNNEL (ELEV 8590) DRIVEN GENERALLY S 40 W FOR 260 FT TO CAVED AREA. MIDDLE ADIT (ELEV 8760) LOCATED 550 FT SW OF LOWER ADIT AND IS DRIVEN GENERALLY S 22 E FOR 160 FT, THENCE S 5 E FOR 250 FT TO FACE, AT WHICH 25 FT OF DRIFT DEVELOPED AT WNW TO ESE; AT 225 FT FROM PORTAL, 140-FT NE DRIFT AND 130-FT SW DRIFT DRIVEN ON VEIN. UPPER ADIT (ELEV 9040) LOCATED 1100 FT SW OF LOWER PORTAL IS DRIVEN S 5 E FOR 120 FT TO FACE (VEIN), AT WHICH 50-FT WSW AND 85-FT ENE DRIFTS DRIVEN. ONE SHAFT OF UNKNOWN DEPTH LIES 250 FT WSW OF LOWER PORTAL.

Comment (Deposit): MINE DEVELOPED ON TWO PRINCIPAL VEINS. GOLDEN CROSS VEIN TRENDS N 69 E, 86 NW IN UPPER TUNNEL AND IRREGULARLY N 45 TO 70 E, 65 NW AND 81 TO 85 SE IN PRINCIPAL DRIFT OF MIDDLE TUNNEL. GOLDEN SLIPPER VEIN TRENDS N 75 E, VERTICAL IN PRINCIPAL DRIFT OF UPPER TUNNEL. LIMONITE-STAINED CLAY GOUGE CONTAINS PYRITE, CALCITE, AND CHLORITE.

References

Reference (Deposit): BLM MINERAL SURVEYS MS 14152, 15230, 15231

Reference (Deposit): CROSS, WHITMAN, AND OTHERS, 1905, DESCRIPTION OF THE NEEDLE MOUNTAINS QUADRANGLE, COLORADO: USGS FOLIO 131.

Reference (Deposit): SCHMITT, L.J., AND RAYMOND, W.H., 1977, GEOLOGY AND MINERAL DEPOSITS OF THE NEEDLE MOUNTAINS DISTRICT, SOUTHWESTERN COLORADO: USGS BULL. 1434, 40 P.

Reference (Deposit): STEVEN, T.A., AND OTHERS, 1969, MINERAL RESOURCES OF THE SAN JUAN PRIMITIVE AREA, COLORADO: USGS BULL. 1261-F.

Reference (Deposit): SCOTT, D.C., 1983, MINERAL INVESTIGATION OF THE WEST NEEDLE WILDERNESS STUDY AREA AND THE BLM WEST NEEDLE CONTIGUOUS WILDERNESS STUDY AREA, LA PLATA AND SAN JUAN COUNTIES, COLORADO: USBM MLA 35-83, P. 6, 26-35

Colorado Mining Photos

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