Rossness & Larson Mine, Homer Mining District, Kenai Peninsula Borough, Alaska, USAi

Regional Level Types
Rossness & Larson Mine	Mine
Homer Mining District	Mining District
Kenai Peninsula Borough	Borough
Alaska	State
USA	Country

This prospect is within the Kenai Fjords National Park; the park is closed to mineral entry.
Location: The Rossness and Larson mine is about 0.2 miles north of VAMB Mid on the north shore of the North Arm of Nuka Bay. The property consists of three short adits, numerous open cuts, and the ruins of the mill and camp. Two of the adits are near the beach at 30 and 50 feet above sea level; they are on each side of a small stream which drains into the cove. The third adit is at an elevation of 107 feet and about 250 feet northwest of the lower tunnels.
Geology: The host rock of the prospect is graywacke and thin slate interbeds of the Cretaceous Valdez Group (Richter, 1970). The quartz veins of this prospect consist of white crystalline quartz with various amounts of sulfides. Arsenopyrite is the dominate sulfide with minor amounts of pyrite. Gold occurs as free gold and associated with arsenopyrite. The veins at this prospect are lens shaped and generally follow the bedding which strikes N30W and dips 67S (Pilgrim, 1933). They range from less than one inch to over four feet in width. The southwest adit is 30 feet in length and follows a stockwork of parallel quartz veins. The veins range in width from 0.1 to 0.5 foot and strike N30W and dip 67S. A composite sample across four of these veins assayed 26 ppm gold (Richter, 1970). The northwest adit is caved and appears to have followed a single quartz-arsenopyrite vein that trends east-west and dips 80S. Richter (1970) sampled this vein and it contained 0.05 ppm gold. The upper adit at 110 foot elevation trends east-west and dips 80S. There are no assay results from this adit. North of the two adits near the beach, there is a pyritized, light colored dike swarm which trends N20W. A sample of this dike swarm contained 0.028 ounces of gold per ton (Pilgrim,1933).
Workings: According to Pilgrim, (1933) the mine produced some gold during the 1931-33 period but it was inactive during Capps' 1936 visit (Capps, 1938, p. 32). Three adits totaling 170 feet in length and numerous surface cuts occur on the property. Composite samples by Richter (1970) of the southwest veins assayed 26 ppm gold. Samples by Pilgrim (1933) assayed between 0.08 and 0.064 ounces of gold and 0.40 ounces of silver per ton. A sample of the pyritic dike assayed 0.028 ounces of gold per ton (Pilgrim,1933).
Age: Tertiary; Boden and others (1991) report other veins in the district are about 55 m.y. old.
Alteration: Borden and others (1991) report carbonization, sulfidization, sericitization, and silicification of the wall rock adjacent to the veins.
Reserves: None.

Commodities (Major) - Au; (Minor) - Ag
Development Status: Undetermined.
Deposit Model: Low-sulfide, Au-quartz vein (Cox and Singer, 1986; model 36a)

Other Databases

Link to USGS - Alaska:	SV018

Other Regions, Features and Areas containing this locality

References