Fielder & Hemple Prospect, Copper River Mining District, Valdez-Cordova Census Area, Alaska, USAi

Regional Level Types
Fielder & Hemple Prospect	Prospect
Copper River Mining District	Mining District
Valdez-Cordova Census Area	Census Area
Alaska	State
USA	Country

Nelson and others (1985) interpret the country rocks as accreted ocean crust. Crowe and others (1992; 1993) and Sainsbury (1993) discuss the genesis of the volcanogenic massive sulfide deposits in this area. Chugach Alaska Corporation, Anchorage, Alaska has control of these lands.
Location: This prospect is at an elevation of about 700 ft. on the north side of inner Landlocked Bay, and about 0.5 mile north of VABM Dick. It is in the W1/2 sec. 6, T. 12 S., R. 7 W., of the Copper River Meridian. The site location is accurate to within 1000 ft. This location corresponds to site C-74 in Jansons and other (1984) and to #14 in Cobb (1972: MF-392).
Geology: The deposit at this prospect is in mafic volcanic and sedimentary rocks of the Tertiary Orca Group (Nelson and others, 1985). It consists of a 24-foot-wide shear zone in pillow basalts and slates that contains small masses of sulfides and quartz as well as sulfide-rich stringers. The zone is traceable for at least 1,500 feet along strike (Capps and Johnson, 1913). The sulfide minerals are chalcopyrite, pyrite, and pyrrhotite. Sampling by Mihelich and Wells (1957) gave the following results: five chip samples from the 1200 ft. adit contained <0.1% to 1.1% Cu, <0.1 to 1.3% Zn, trace to 0.32 oz. Au/ton, and 0.02 to 0.32 oz.Ag/ton. Sampling by Jansons and others (1984) gave the following results: five chip samples contained 0.19% to 2.6% Cu, 800 ppm to 0.7% Zn, 2.6 ppm to 3.7 ppm Ag, and <0.03 ppm to 0.12 ppm Au. Selected grab samples contained 4.5% and 4.6% Cu, 1.7% and 1.8% Zn, 4.1 ppm and 13 ppm Ag, and 0.06 ppm and 3.1 ppm Au.
Workings: Capps and Johnson (1913) reported four adits having the following lengths: 1200 ft., 250 ft., 65 ft., and 18 ft. There were also minor surface workings. Only two adits could be found during later exploration (Jansons and others, 1984). Sampling by Mihelich and Wells (1957) gave the following results: five chip samples from the 1200 ft. adit contained <0.1% to 1.1% Cu, <0.1 to 1.3% Zn, trace to 0.32 oz. Au/ton, and 0.02 to 0.32 oz.Ag/ton. Sampling by Jansons and others (1984) gave the following results: five chip samples contained 0.19% to 2.6% Cu, 800 ppm to 0.7% Zn, 2.6 ppm to 3.7 ppm Ag, and <0.03 ppm to 0.12 ppm Au. Selected grab samples contained 4.5% and 4.6% Cu, 1.7% and 1.8% Zn, 4.1 ppm and 13 ppm Ag, and 0.06 ppm and 3.1 ppm Au.
Age: Probably Tertiary based on the age of the host rocks.
Reserves: Inferred reserves ( Mihelich and Wells, 1957) are 6,300 tons @ 1.3% Cu.

Commodities (Major) - Cu, Zn; (Minor) - Ag, Au
Development Status: Yes; small
Deposit Model: Cyprus massive sulfide (Cox and Singer, 1986; model 24a)

Other Databases

Link to USGS - Alaska:	CV019

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References