Mizpah Ledge

Prospect, Inactive

Alternative names

Kennedy, Pullen, Davis

Commodities and mineralogy

Main commodities Au
Other commodities Ag
Ore minerals arsenopyrite; chalcopyrite; galena; gold; pyrite; sphalerite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale SR
Quadrangle map, 1:63,360-scale B-7
Latitude 60.2666
Longitude -149.4208
Nearby scientific data Find additional scientific data near this location
Location and accuracy The prospect is situated in the NE1/4 section 15, T. 2 N., R. 1 W., of the Seward Meridian. It is located on a small point of land on the east side of Lost Lake. The portal is at an elevation of about 1,900 feet about 35 feet from the shore of the lake. This is location 84 of Cobb and Tysdal (1980) and location S-209 of Jansons and others (1984). This location is accurate to within 300 feet.

Geologic setting

Geologic description

The prospect consists of quartz stringers and pods as much as 6 inches wide in a 2- to 4-foot-wide shear zone. The zone strikes N10E and dips 70E (Hoekzema and Sherman, 1983). The host rock is slate and sandstone of the Valdez Group of Late Cretaceous age (Cobb and Tysdal, 1980). The host rock strikes N18E and dips vertically (Martin and others, 1915). Mineralization consists of abundant arsenopyrite and lesser amounts of chalcopyrite, galena, pyrite, sphalerite, and gold. Gold occurs free in the quartz and in the sulfide minerals (Martin and others, 1915). The sulfide mineralization appears to pinch out completely in the adit (Hoekzema and Sherman, 1983).
Workings on the prospect consist of a 5- by 30-foot open cut and a 28-foot-long adit at its north end (Hoekzema and Sherman, 1983). Two samples assayed 3.5 ounces of gold per ton and 10.3 ppm gold along with 3,500 and 6,500 ppm arsenic, respectively (Hoekzema and Sherman, 1983). The first sample was a 4-inch-wide chip sample of a quartz vein exposed in the open cut. The second sample was a grab sample from the dump.
Geologic map unit (-149.4229544469, 60.2660400131688)
Mineral deposit model Low-sulfide Au-quartz veins (Cox and Singer, 1986; model 36a)
Mineral deposit model number 36a
Age of mineralization Cretaceous or younger; the veins cut rocks of the Valdez Group of Late Cretaceous age.

Production and reserves

Workings or exploration
Workings on the prospect consist of a 5- by 30-foot open cut and a 28-foot-long adit at its north end (Hoekzema and Sherman, 1983). The open cut and adit both strike N2E.
Two samples assayed 3.5 ounces of gold per ton and 10.3 ppm gold along with 3,500 and 6,500 ppm arsenic, respectively (Hoekzema and Sherman, 1983). The first sample was a 4-inch-wide chip sample of a quartz vein exposed in the open cut. The second sample was a grab sample from the dump.
Indication of production None
Reserve estimates The U.S. Bureau of Mines estimated a resource of 10 tons of ore containing 1 ounce of gold per ton and 0.5 ounce of silver per ton (Hoekzema and Sherman, 1983).

References

References

Hoekzema, R.P., and Sherman, G.E., 1983, Mineral investigations in the Chugach National Forest, Alaska (Peninsula study area): U.S. Bureau of Mines in-house report; held at U.S. Bureau of Land Management Alaska State Office, Anchorage, 524 p.
Reporters Jeff A. Huber and Carol S. Huber (Anchorage)
Last report date 12/10/2001