Kenai Chrome

Mine, Inactive

Alternative names

Star #4
Chrome Queen

Commodities and mineralogy

Main commodities Cr
Ore minerals chromite

Geographic location

Quadrangle map, 1:250,000-scale SV
Quadrangle map, 1:63,360-scale B-4
Latitude 59.378
Longitude 151.476
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Kenai Chrome mine and the Chrome Queen mine are located in section 21, T. 9 S., R. 13 W., of the Seward Meridian. The site of the Kenai Chrome mine is labeled on the 1:63,360 topographic quadrangle. The site is near the head of the Windy River in the southern half of section 21 at approximately 1,400’ elevation. The location is accurate, within about 50 meters.

Geologic setting

Geologic description

The Red Mountain ultramafic complex covers about 7 square miles and is part of the informally named Border Ranges ultramafic and mafic complex of Burns (1985). The Jurassic Border Ranges complex is thought to be the dismembered basal section of an island arc complex (Burns, 1985) which extends from the tip of the Kenai Peninsula to east of Sutton, Alaska.
The dunite body is a klippe thrust over the Cretaceous McHugh Complex graywackes and slates. The margin of the Red Mountain klippe is serpentinized and the gross overall structure of the klippe is an elongated basin.
The Kenai Chrome mine is located on the Star No. 4 claim at an elevation of 2,600 feet on the north side of the ultramafic body. The chromite seams can be traced for almost 1,000 feet but it is less than a foot thick for over half this distance (Guild, 1941). The main ore body was 625 feet long and had a maxium thickness of 9.8 feet. The strike of the layering is N 10 W and the dip varies from 35 W to 70 W except where minor folding has caused variations. Several small faults strike more or less at right angle to the chromite banding. The Cr/Fe ratio of the chromite generally varies from 2.6 to 3.6; at least 90 percent of the chromite is with these limits (Gill, 1922).
Geologic map unit (-151.472094076947, 59.3793816149295)
Mineral deposit model Podiform chromite (Cox and Singer, 1986; model 8a).
Mineral deposit model number 8a
Age of mineralization Jurassic; based on the age of the ultramafic body that hosts the deposit.

Production and reserves

Workings or exploration The area was discovered about 1910 to 1915, and some minor development and production occurring in 1920 (Brooks, 1921). During WW II, the Bureau of Mines drilled over thirty diamond drill holes to evaluate the deposits. In 1942 through 1944, production from the Chrome Queen mine totaled 6,650 tons of 40 to 42 percent chromic oxide ore. Star No.4 produced 15,000 tons at 46 percent chromic oxide about 1954, from 490 feet of underground workings. Ore from the Star No. 4 averaged 40 to 46 percent chromic oxide. On-going exploration continued through the late 1980s. Anaconda Minerals drilled 6 diamond drill holes about 1982 and 83 which tested the Horseshoe Stringer Zone and the Turner Stringer Zone (Bill Ellis, 1999, personal communication). Anaconda Minerals also flew regional airborne geophysic over the body in the early 1980s.
Indication of production Yes; small
Reserve estimates The remaining reserve are estimated to be 1.5 million tonnes of contained chromic oxide in 33 deposits (Foley, 1992). About 88,000 tonnes chromic oxide are contained in 20 relative high-grade deposits with more than 20 percent chromite. The bulk of the reserves, 1.35 million tonnes are in three low -grade deposits that contain 5 to 6 percent chromic oxide (Foley, 1992). These are the Turner Stringer Zone, (1.13 million tonnes chromic oxide), the Star Stringer Zone (189,000 tonnes chromic oxide) and the Horseshoe Stringer Zone (26,000 tonnes chromic oxide) (Foley, 1992).
Production notes From the Red Mountain area about 26,000 tonnes of ore containing from 38 to 43 percent chromic oxide were produced between 1943 and 1958 (Foley, 1992). From 1943 to 1958, the Chrome Queen mine produced 6,650 tonnes and the Star No. 4 mine produced 19,350 tonnes (Foley and Barker, 1985).

Additional comments

The 03/09/1999 version of this record misquoted the Foley,1992, reference, which lists abbreviations of mt as metric tons not million tons. Production notes on Chrome Queen mine and Star No. 4 mine were moved to this record from record SV015 'Unanmed (Red Mountain)'.

References

MRDS Number A010645; A010672

References

Reporters Jeff A. Huber (Anchorage); V.C. Zinno (Alaska Earth Sciences, Inc.)
Last report date 3/15/2016