Rock Creek (placer)

Mine, Inactive

Commodities and mineralogy

Main commodities Au
Other commodities Ag
Ore minerals gold; limonite; magnetite; scheelite
Gangue minerals garnet

Geographic location

Quadrangle map, 1:250,000-scale NM
Quadrangle map, 1:63,360-scale C-1
Latitude 64.6117
Longitude -165.4172
Nearby scientific data Find additional scientific data near this location
Location and accuracy Rock Creek is a southwest-flowing tributary of Snake River with headwaters on the south flank of Mount Brynteson. Placer workings are present along about 1.5 miles of Rock Creek; the approximate midpoint of the workings are in the NW1/4 section 23, T. 10 S., R. 34 W., Kateel River Meridian. The most extensive deposits were developed between elevations of about 200 to 350 feet. The location is the approximate discovery point (Francisco Placer, U.S. Mineral Survey No. 721) of the placer deposit. It is locality 98 of Cobb (1972 [MF 463], 1978 [OFR 78-93]).

Geologic setting

Geologic description

The main Rock Creek placer deposit is an alluvial placer developed in the flood plain of modern Rock Creek. The deposit was discovered by Lindeberg, Lindblom, and Brynetson in the fall of 1898 within a few days or weeks of the discovery of the Anvil Creek placer (NM236). Rock Creek was visited by the U.S. Geological Survey in 1903 (Collier and others, 1908). At that time, one company, presumably the Pioneer Mining Company, was working on five claims. Gold was distributed throughout pay gravel that was only about 5 feet deep. The gold was mainly fine with a few rough nuggets. Semiangular scheelite occurred in the concentrates along with magnetite, limonite, and garnet. The part of the deposit in the main Rock Creek flood plain was as much as 300 feet wide on the No. 4 Above claim and an adjacent west bench claim. It was relatively shallow, about 5 to 12 feet deep, and was developed on hard schist bedrock where indentations and irregularities acted as riffles. This placer deposit was largely worked out by 1905, probably by hand shovel-in and scraper operations. A series of hydraulic pits on the east side of Rock Creek above Sophie Gulch appears to be on a residual placer developed on the main Rock Creek sheeted vein complex (NM207). This part of the placer may have been developed somewhat later, as was the residual scheelite-rich placer mined in Sophie Gulch in 1916 and 1917 (NM208). Cathcart (1920) reported mining on Rock Creek in 1918; Smith (1926) reported mining in 1924. Scheelite reportedly was mined in 1943 (Anderson, 1947). Thorne and others (1948) reported scheelite along the main 1.5 mile length of the Rock Creek placer. Coats (1944) believed that Rock Creek was one of the more important scheelite-bearing creeks in the Nome area. In general, it is difficult to distinguish between descriptions of mining along Rock Creek and that along the more limited Sophie Gulch deposit. Total production from the Rock Creek placer has been estimated to be about 30,000 ounces of gold.
Geologic map unit (-165.419807287393, 64.6109345247345)
Mineral deposit model Alluvial placer Au (Cox and Singer, 1986; model 39a).
Mineral deposit model number 39a
Age of mineralization Quaternary.

Production and reserves

Workings or exploration The placer deposit in Rock Creek was discovered in the fall of 1898 by the pioneers of the Nome district, Jafet Lindeberg, Erik O. Lindblom, and John Brynetson. The discovery claim was named Francisco. Claims extended upstream to the 6 Above claim, about at the confluence with Albion Creek. By 1905, the date of the patent survey, a placer deposit as much as 300 feet wide had been worked continuously from the Francisco claim to the 5 Above claim in the main flood plain of Rock Creek. An east side residual placer appears to have been worked in a series of hydraulic pits above Sophie Gulch. When the claims were patented in 1906, the value of improvements reported by the Pioneer Mining Company was in excess of 300,000 dollars. Estimated total production was about 30,000 ounces of gold. Metcalfe and Tuck (1942) thought that there was sufficient pay left, probably mainly in a buried bench channel (NM210), to justify a small dragline operation at Rock Creek.
Indication of production Yes
Production notes Estimated total production was about 30,000 ounces of gold.

References

MRDS Number A012897

References

Metcalfe, J.B., and Tuck, Ralph, 1942, Placer gold deposits of the Nome district, Alaska: Report for U.S. Smelting, Refining, and Mining Co., 175 p.
Reporters C.C. Hawley and Travis L. Hudson
Last report date 7/10/2000