The Porphyry Dike Mine is a gold mine located in Lewis and Clark county, Montana at an elevation of 7,480 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.
Elevation: 7,480 Feet (2,280 Meters)
Primary Mineral: Gold
Lat, Long: 46.42778, -112.28750
Map: View on Google Maps
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.
Porphyry Dike Mine MRDS details
Primary: Porphyry Dike Mine
County: Lewis and Clark
District: Rimini District
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.
Record Type: Site
Operation Category: Past Producer
Operation Type: Unknown
Year First Production: 1892
Discovery Year: 1890
Discovery Method: Ore-Mineral Not In Place
Years of Production:
Deposit Size: S
General Physiographic Area: Rocky Mountain System
Physiographic Province: Northern Rocky Mountains
Mineral Deposit Model
Description: Large Scale Volcanic And Igneous Intrusive Activities Boulder Batholith
Description: Jointing, Overlapping Of Pyroclastics And Flow Units Thin Dikes And Faults
Alteration Type: L
Alteration Text: Sericitization, Kaolinization
Age Type: Associated Rock
Age Young: Pliocene
Age Type: Host Rock
Age Young: Pliocene
Comment (Development): REFERENCE MATERIAL INDICATES THAT THE ANACONDA CO. HAS THOROUGHLY SAMPLED THIS DEPOSIT BY DRILLING
Comment (Commodity): LIMONITE STAINED FRACTURES SAID TO BE PARTICULARLY FAVORABLE PLACES FOR GOLD OCCURRENCE
Comment (Location): NEAR HEAD OF MONITOR CREEK. ; INFO FROM LAND.ST :(1954)
Comment (Production): USGS BULL 1151, P. 115.
Comment (Workings): TWO 1200 FT ADITS UNDER THE PIT, BOTH WITH NUMEROUS CROSSCUTS AND CONNETING VERTICAL WORKINGS. OPEN PIT IS 150 FT WIDE, 300 FT LONG AND 150 FT DEEP.
Comment (Deposit): THE RICHEST ORE MINED AT THE PORPHYRY DIKE MINE WAS REMOVED FROM A VERTICALLY SHEETED ZONE OF THOROUGH AND DEEP OXIDATION ALONG WHICH CONCENTRATION OF GOLD IN OPEN JOINTS COULD EASILY OCCUR
Comment (Deposit): 4 INTERLAYERED AND OVERLAPPING PYROCLASTIC AND FLOW UNITS IN THE RHYOLITE. THESE UNITS ARE CUT BY THIN DIKES AND BY FAULTS. PRIMARY GOLD WAS DISSEMINATED IN THE CLOSELY HOINTED, LAMINATED FLOW ROCKS. PART OF FREE GOLD HAS BEEN WASHED INTO OPEN JOINTS AND DESCENDED THROUGH THE RHYOLITE AND CONCENTRATED. RICHEST ORE WAS FROM A VERTICAL SHEETED ZONE.
Reference (Deposit): USGS BULL 842, P. 259-60.
Reference (Deposit): USGS BULL 1151, P. 114-16, PL. 1.
Reference (Deposit): USGS BULL 527, P. 84-85.
Reference (Production): RUPPEL, E. T., 1963 , GEOL. OF THE BASIN QUAD., JEFF., LEWIS & CLARK, POWELL CO., MONT USGS BULL NO 1151