Occurrence, Active

Alternative names


Commodities and mineralogy

Main commodities Ag; Cu; Pb; Zn
Other commodities Co
Ore minerals chalcopyrite; pyrite; sphalerite
Gangue minerals epidote; quartz

Geographic location

Quadrangle map, 1:250,000-scale MG
Quadrangle map, 1:63,360-scale B-2
Latitude 62.3258
Longitude -153.7712
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Clough occurrence is in a saddle that separates two northwest-trending ridge lines, about 2.0 kilometers west of the north end of Smith Lake. It is at an elevation of about 4,500 feet in the SW1/4 sec. 20, T. 26 N., R. 24 W., of the Seward Meridian. (The occurrence as shown in Bundtzen, Harris, and Gilbert (1997; map no. 10) is mislocated.)

Geologic setting

Geologic description

The Clough occurrence is a small but rich deposit in skarn adjacent to an altered, east-west-trending felsic (?) dike. The skarn is in argillaceous limestone of the mid-Silurian Terra Cotta Mountains Sandstone, a unit of the Dillinger sub-terrane (Bundtzen, Harris, and Gilbert, 1997).
The principle sulfides are massive pyrite and sphalerite in veins up to 8 centimeters thick; they and a trace of chalcopyrite occur in an epidote-quartz skarn. One grab sample of mineralization contained 13.0 percent zinc, 0.11 percent lead, 0.50 percent copper, 26 grams of silver per tonne, and 300 parts per million cobalt. (Bundtzen, Kline, and Clough, 1982; Bundtzen, Harris, and Gilbert, 1997).
In 2008, this prospect was one of several in a block of claims that covered more than 70 square miles, known collectively as the BMP project (International Tower Hill Mines, Ltd., 2008).
Geologic map unit (-153.773422088787, 62.325187616245)
Mineral deposit model Low temperature lead-zinc skarn (Cox and Singer, 1986; model 18c).
Mineral deposit model number 18c
Alteration of deposit None.

Production and reserves

Workings or exploration The Clough occurrence was found by Jim Clough of Alaska Division of Geological and Geophysical Surveys during a geologic mapping program in 1981 (Bundtzen, Kline, and Clough, 1982). As of 2008, the prospect was within a large block of claims called the BMP project by International Tower Hill MIne, Ltd. (2008).
Indication of production None

Additional comments

Similar to Rat Fork-Headwall (MG059) and Rat Fork-Base (MG058) prospects.