Camp Creek Prospect (tributary to Lost River), Lost River Valley, Port Clarence Mining District, Nome Census Area, Alaska, USAi

Regional Level Types
Camp Creek Prospect (tributary to Lost River)	Prospect
Lost River Valley	Basin
Port Clarence Mining District	Mining District
Nome Census Area	Census Area
Alaska	State
USA	Country

Location: Camp Creek is an east tributary to Cassiterite Creek about 0.75 miles upstream from Cassiterite Creek's mouth on Lost River and 2,000 feet south of the Lost River Mine (TE048-TE051). The prospect is on the south side of Camp Creek at elevations of 300 to 500 feet. This locality was not identified separately by Cobb and Sainsbury (1972). Cobb (1975) summarized relevant references under the name 'Lost River'.
Geology: Fluorite- and beryllium-bearing veins and veinlets are common in Ordovician limestone along a 2,400 foot-long east-west trending zone on the south side of Camp Creek (Sainsbury, 1969, plate 3). The principal controls on the veins and veinlets are nearly vertical sheeted fractures, closely spaced joints, brecciated zones, and borders to igneous dikes. Mineralization includes fluorite, diaspore, tourmaline, muscovite, chrysoberyl, hematite, and todorokite. Stibnite in fluorite and diaspore has been identified on the ridgeline east of Camp Creek. USBM diamond drilling encountered stannite- and pyrite-bearing sulfide zones within the fluorite and beryllium-bearing mineralization. Nineteen surface samples contained 0.31 to 6.00% BeO; the fluorite content, determined for 8 of these samples, ranged from 54.6 to 62.4% (Sainsbury, 1963, p. 7). Diamond drilling by the USBM and Lost River Mining Corporation enabled a resource calculation of 2,116,000 tons of 30.6% fluorite in an open-pit configuration and 1,695,000 tons of 30.0 % fluorite that would require underground mining (WGM, 1972, p. 63). These calculations used a cut-off grade of 15% fluorite and an overall weighted average of at least 23% fluorite. The general dimensions of the mineralized zone determined by this drilling are 3,000 feet long, up to 130 feet thick, and 300 feet downdip (apparently shallow to moderate south dip); mineralization is open along strike and dip (WGM, 1973, p. 53). The Lost River Mining Corporation work did not identify other valuable constituents in the mineralized material.
Workings: Surface dozer trenches, 13 USBM diamond drill holes totalling 2,158 feet, and 23 Lost River Mining Corporation diamond drill holes totalling 8,146 feet have been completed on the prospect.
Age: The age of the mineralization is assumed to be related to the development of tin systems in the Lost River area and therefore Late Cretaceous, the age of the tin-mineralizing granites there (Hudson and Arth, 1983).
Alteration: Fluorite and beryllium-bearing mineralization is thought to be a type of distal alteration to tin metallizing sytems in this area. Mass balance calculations show significant SiO2, Al2O3, alkali, and fluorine enrichment with mineralization (Sainsbury, 1968, p. 1567). The limestone is commonly dolomitized but the relation of this alteration to sulfide and fluorite mineralization is not clear.
Reserves: Diamond drilling by the USBM and Lost River Mining Corporation enabled a resource calculation of 2,116,000 tons of 30.6% fluorite in an open-pit configuration and 1,695,000 tons of 30.0 % fluorite that would require underground mining (WGM, 1972, p. 63). These calculations used a cut-off grade of 15% fluorite and an overall weighted average of at least 23% fluorite. The general dimensions of the mineralized zone determined by this drilling are 3,000 feet long, up to 130 feet thick, and 300 feet downdip (apparently shallow to moderate south dip); mineralization is open along strike and dip (WGM, 1973, p. 53).

Commodities (Major) - Be, fluorite
Development Status: None
Deposit Model: Fluorite-, beryllium-, and sulfide-bearing veins and replacements in limestone

Other Databases

Link to USGS - Alaska:	TE047

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References