Glass & Heifner

Prospect, Inactive

Alternative names

Little Creek
Earl Mount

Commodities and mineralogy

Main commodities Ag; Au
Other commodities Cu; Pb; Zn
Ore minerals arsenopyrite; galena; gold; sphalerite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale SV
Quadrangle map, 1:63,360-scale C-2
Latitude 59.553
Longitude -150.678
Nearby scientific data Find additional scientific data near this location
Location and accuracy This prospect is about one mile northwest of the mouth of Ferrum Creek. Ferrum Creek drains into a northwestern trending arm of Nuka Bay, called Beauty Bay. A road leads to the property from the Nuka River flats airstrip. The prospect consists of a 400 foot adit, numerous prospect pits and trenches. The adit is at 200 feet elevation and the prospect pit can be found along the hillside above the adit at an elevation of 350 feet. This is Cobb's (1972, MF-397) location 19 and Richter's (1970) location 2. Cobb (1979, OFR 80-87) summarized the relevant references for this prospect under the name Glass and Heifner. This location is accurate to within 300 feet.

Geologic setting

Geologic description

Cretaceous Valdez Group massive graywacke is exposed in all the underground workings and in most of the surface outcrops. The only black slate and siltstones in the vicinity are exposed in the eastern and southeastern most prospect pits. Foliation and bedding in this area trends N10 to 30E and dips 50 to 60NW (Richter, 1970).
At least three major quartz veins are exposed on the property. All the quartz veins generally strike east-west and dip to the north. The northern most and principal vein is sporadically exposed in the surface working for about 350 feet and underground for 125 feet. At its western extremity, the vein has a consistent moderate dip of 40 to 60N, but toward the east the dip steepens to more than 80N. The vein ranges from one to five feet wide and consists of white quartz with massive lens and sheets of arsenopyrite (Richter, 1970). Two samples cut randomly across the vein in the main drift assayed 72 and 0.2 ppm gold (Richter, 1970).
A second and much shorter vein is exposed 100 feet south of the main vein in two surface trenches about 100 feet apart. The vein generally strikes east-west and dips 84 to 87N. This vein contains only minor sulfides, but Pilgrim (1933) reported that abundant free coarse gold was panned from samples of this vein. This vein does not extend in depth to the underground workings.
Sixty feet further south, a third vein is exposed over a distance of 150 feet in pits and trenches. The third vein is also exposed in a short drift off the main adit. The vein has been stoped from the adit to the surface, the stoped area contained abundant galena and free gold (Pilgrim, 1933). Overall, the vein is lens shaped and pinches out to the east and west. A channel sample from the vein (Richter, 1970) contained 2 ppm gold.
Geologic map unit (-150.680096362038, 59.5524127519534)
Mineral deposit model Low-sulfide, Au-quartz vein (Cox and Singer, 1986; model 36a)
Mineral deposit model number 36a
Age of mineralization Tertiary; Boden and others (1991) report other veins in the district are about 55 m.y. old.
Alteration of deposit Borden and others (1991) report carbonization, sulfidization, sericitization, and silicification of the wall rock adjacent to the veins.

Production and reserves

Workings or exploration Four hundred and fifty feet of tunnels were driven in 1932 through 1934, but the amount of ore delineated was not enough to justify a mill (Capps, 1938). Some small-scale, surface mining took place in 1967 (Richter, 1970).
Indication of production Yes; small
Reserve estimates None.

Additional comments

This occurrence is within Kenai Fjords National Park, consequently the area is closed to mineral entry.

References

MRDS Number A010578

References

Pilgrim, E.R., 1933, Nuka Bay district, in Stewart, B. D., Making mining investigations and mine inspection in Alaska, biennium ending March 31, 1933: Alaska Territorial Department of Mines Annual Report 1933B, p. 26-51.
Reporters Jeff A. Huber (Anchorage)
Last report date 2/15/1999