Masonville District

The Masonville District is a gold and silver mine located in Larimer county, Colorado at an elevation of 5,801 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: Masonville District

Commodity

Primary: Gold
Primary: Silver
Secondary: Tungsten
Tertiary: Copper
Tertiary: Nickel

Location

State: Colorado
County: Larimer
District: Masonville District

Land Status

Land ownership: Federal
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

Not available

Ownership

Not available

Production

Not available

Deposit

Record Type: District
Operation Category: Producer
Deposit Type: Vein
Operation Type: Unknown
Year Last Production: 1955
Discovery Year: 1900
Discovery Method: Ore-Mineral In Place
Years of Production:
Organization:
Significant: N
Deposit Size: S

Physiography

General Physiographic Area: Interior Plains
Physiographic Province: Great Plains Province
Physiographic Section: Colorado Piedmont

Mineral Deposit Model

Not available

Orebody

Not available

Structure

Type: R
Description: Front Range Uplift, Cheyenne Basin

Type: L
Description: Big Thompson Anticline, Milner Mountain Fault, Fletcher Hill (Buck Horn) Fault, Masonville Anticline, Buckhorn Syncline, Masonville Stock , Redstone Fault

Alterations

Alteration Type: L
Alteration Text: Hydrothermal Montmorillonite In Fractures; Wallrock Silicification ; Sericitization Of Andalusite In Schist

Rocks

Name: Tonalite
Role: Associated
Age Type: Host Rock
Age Young: Neoproterozoic

Name: Tonalite
Role: Associated
Age Type: Associated Rock
Age Young: Neoproterozoic

Analytical Data

Analytical Data: ASSAYS OF MASON MINE VEIN MATERIAL GAVE 0.02 TO 0.04 OZ/TON AU, 0. 4 TO 0.6 OZ/TON AG.

Materials

Ore: Chalcopyrite
Ore: Scheelite
Ore: Pyrite
Gangue: Hematite
Gangue: Quartz
Gangue: Limonite
Gangue: Epidote
Gangue: Malachite
Gangue: Montmorillonite

Comments

Comment (Location): DISTRICT LIES 0.5 TO ONE MILE NNW TO NE OF MASONVILLE, ACCESSIBLE FROM ROADS UP BUCKHORN AND REDSTONE CREEKS. DISTRICT EXTENDS ONTO HORS ETOOTH RESERVOIR QUAD. LAT-LONG GIVEN IS FOR PRINCIPAL CROSSROADS AT M ASONVILLE (SEC. 14-15 QUARTER CORNER). ; INFO FROM LAND.ST :1980

Comment (Development): PATENTED CLAIM INDICATES DISCOVERIES AS EARLY AS 1900. MASON RANC H AND CARTER MINES WORKED BETWEEN 1915 AND 1920 FOR AU. SMALL INTERMIT TENT AU-AG PRODUCTION RECORDED FOR 1935, 1936, 1940, 1941, AND 1943. M INOR W PRODUCTION PROBABLY IN 1950S.

Comment (Workings): PRINCIPAL MINES AND CLAIMS DEVELOPED BY DRIFTS AND TUNNELS FROM 1 00 TO 1000 FT LONG AND BY SHAFTS UP TO 150 FT DEEP.

Comment (Deposit): METASEDIMENTARY ROCKS ARE LOW-GRADE REGIONALLY METAMORPHOSED TO G REENSCHIST AND EPIDOTE-AMPHIBOLITE FACIES AND ARE INTRUDED BY PRECAMBR IAN MASONVILLE TONALITE STOCK ESSENTIALLY ALONG SCHISTOSITY WITH DIKEL IKE EXTENSIONS AT BOTH ENDS. LARAMIDE UPLIFT AND FOLDING (ONE OF SERIE S OF SE-PLUNGING EN ECHELON FOLDS ON MARGIN OF UPLIFT) ACCOMPANIED BY REACTIVATION OF NW-TRENDING PRECAMBRIAN (?) STRUCTURES NOW SEEN AS FLE CHER HILL FAULT, WHICH TRUNCATES SW LIMB OF MASONVILLE ANTICLINE AND S W SIDE OF MASONVILLE STOCK. JOINTS AND FRACTURES RELATED TO STOCK EMPL ACEMENT SHOW HYDROTHERMAL MINERALIZATION SEQUENCE OF EPIDOTE, SERICITE , QUARTZ, MONTMORILLONITE, FE OXIDES, PYRITE, CHALCOPYRITE, AU, AG. WO LFE DID NOT CONSIDER MINERALIZATION TO BE EXTENSIVE BECAUSE FRACTURE C ONTROL APPEARED TO BE DUE TO STRUCTURAL FORCES OF VERY LOCAL DEVELOPME NT. BELSER NOTED SCHEELITE TO OCCUR AS FLAKES ON WALLS OF VEINS.

References

Reference (Deposit): BELSER, CARL, 1956, TUNGSTEN POTENTIAL IN CHAFFEE, FREMONT, GUNNISO N, LAKE, LARIMER, PARK, AND SUMMIT COUNTIES, COLORADO: USBM IC-7748, P . 18.

Reference (Deposit): BLM MINERAL SURVEYS

Reference (Deposit): VANDERWILT, J.W., 1947, MINERAL RESOURCES OF COLORADO: COLORADO MIN ERAL RESOURCES BD., P. 139.

Reference (Deposit): COLORADO DIV. MINES INF. REPTS.

Reference (Production): VANDERWILT, 1947, P. 139; BELSER, 1956, P. 18

Reference (Deposit): WOLFE, J.A., 1953, GEOLOGY OF THE MASONVILLE MINING DISTRICT, LARIM ER COUNTY, COLORADO: COLORADO SCHOOL OF MINES M.SC. THESIS T-789.

Reference (Deposit): BRADDOCK, W.A., AND OTHERS, 1970, GEOLOGIC MAP OF THE MASONVILLE QU ADRANGLE, LARIMER COUNTY, COLORADO: USGS MAP GQ-832.

Reference (Deposit): COBB, H.S., 1960, TUNGSTEN MINES OF COLORADO: COLORADO METAL MINING FUND BD.

Colorado Mining Photos

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