Olsen (Anvil Creek)

Prospect, Inactive

Commodities and mineralogy

Main commodities Au; Sb
Other commodities Cu
Ore minerals gold; pyrite; stibnite
Gangue minerals quartz; talc

Geographic location

Quadrangle map, 1:250,000-scale NM
Quadrangle map, 1:63,360-scale C-1
Latitude 64.5757
Longitude -165.3962
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Olsen lode prospect is at an elevation of about 200 feet on the east side of Anvil Creek. It is 1,000 feet south of the Snake River road switchback where it crosses Anvil Creek and about one-quarter mile south of the mouth of Specimen Gulch. The map location is in the SW1/4 section 36, T. 10 S., R. 34 W., Kateel River Meridian. This is locality 12 of Hummel (1962 [MF 247]). The location is accurate within 500 feet.

Geologic setting

Geologic description

The Olsen prospect consists of two long-abandoned shafts sunk on the east side of Anvil Creek. The workings date from the early 1900s (Mertie, 1918 [B 662-I, p. 425-449]; Cathcart, 1922). A 54-foot shaft was sunk on a north-northwest striking, west-dipping quartz vein. According to the owner, Charles Olsen, the shaft struck stibnite ore at 49 feet and was in stibnite-bearing rock to abandonment of the shaft at 54 feet. A 97-foot shaft was sunk nearby. It reportedly encountered stibnite-bearing ore at 60 feet that continued on the hanging wall of a vein to the bottom of the shaft; the shaft was abandoned due to flooding. Material observed on the dump included finely crystalline stibnite with quartz and pyrite. The material reportedly assayed about 1 ounce of gold per ton, 2.05 dollars worth of silver, and some copper (Cathcart, 1922, p. 239-40). The veins reportedly had talc schist hanging walls about 10 feet thick.
Mertie (1918 [B 662-I, p. 431-432]) believed that the veins were in a fault zone. He noted that graphitic schist walls were cut by nearly vertical quartz veins with a strike of N45E. The veins probably are in the Anvil fault zone as shown by Hummel (1962 [MF 247]), who mapped a wide graphitic zone between two main faults along this part of Anvil Creek. Where the Anvil fault is exposed in the Snake River road cut (NM234), the graphitic schist is highly sheared and contorted in a zone 100 feet wide and locally contains stibnite.
Geologic map unit (-165.398803162946, 64.5749345151022)
Mineral deposit model Low-sulfide Au-quartz veins (Cox and Singer, 1986, model 36a); simple Sb deposits (Cox and Singer, 1986; model 27d).
Mineral deposit model number 36a, 27d
Age of mineralization Probably mid-Cretaceous or younger; see NM207.

Production and reserves

Workings or exploration Five lode claims aligned about N 25 E were located and prospected by Charles Olsen before 1916 (Mertie, 1918 [B 662-I, p. 425-449]). A 97-foot shaft had a 35-foot drift. Workings in 1920 (Cathcart, 1922) included the 97-foot shaft and a 54-foot shaft.
Indication of production Undetermined