Sulphide Queen Mine (Sulphide Queen body), Mountain Pass Mine, Mountain Pass, Mountain Pass District, Clark Mts (Clark Mountain Range), San Bernardino County, California, USAi

Regional Level Types
Sulphide Queen Mine (Sulphide Queen body)	Mine
Mountain Pass Mine	Mine
Mountain Pass	Pass
Mountain Pass District	Mining District
Clark Mts (Clark Mountain Range)	Mountain Range
San Bernardino County	County
California	State
USA	Country

The main ore body of the Mountain Pass deposit is located in secs. 12 & 13, T16N, R13E, SBM, near Mountain Pass, just N of Interstate highway 10 (I-10), and elements of it are visible from the roadway.

A massive carbonatite called the Sulphide Queen body forms the core of the Mountain Pass igneous complex and hosts the bulk of the REE mineral resources in the district. This carbonatite body has an overall length of 730 meters (2,395 feet) and an average width of 120 meters (394 feet) (Olson and others, 1954). The typical ore contains about 10–15 percent bastnäsite (the ore mineral), 65 percent calcite or dolomite (or both), and 20–25 percent baryte, plus other minor accessory minerals (Castor and Nason, 2004). The Sulphide Queen carbonatite body is the largest known mass of high-grade REE ore in the United States. Light REE are preferentially concentrated in the Mountain Pass ore (Castor, 2008). Molycorp ceased its mining of the Mountain Pass REE deposit in 2002 when its permit expired. However, in 2009, Molycorp announced its intentions to resume mining at Mountain Pass by the year 2012. The mine’s open pit, inactive since 2002, covers about 22 hectares (55 acres) of the area and is about 122 meters (400 feet) deep. In July 2009, Molycorp reached an agreement with Arnold Magnetic Technologies Corp. of Rochester, New York, to make permanent magnets using REE mined at Mountain Pass (Mining Engineering, 2009). Molycorp announced that “Plans call for mining to resume at Mountain Pass by 2012, at the rate of about 972 tons/day [972 metric tons per day; 1,000 tons per day] of ore, enough to produce 20 kt [20,000 metric tons; 22,000 tons] of rare earth oxides for sale each year” (Mining Engineering, 2009, p. 8); it has received approval to double its output volume with time. The mine’s peak output 20 years ago was 20,000 metric tons per year of rare earth oxides (Mining Engineering, 2009). Molycorp estimates that the remaining deposit holds 20 to 47 million metric tons (22 to 52 million tons) of ore (Mining Engineering, 2009). The Sulphide Queen carbonatite stock and nearby carbonatite dikes are associated with Proterozoic, potassium-rich, igneous rocks — biotite shonkinite, hornblende and biotite syenite, and granite that intruded Precambrian metamorphic and igneous rocks (Olson and others, 1954; Castor, 2008). The Sulphide Queen body was originally mapped as three rock types with local variations — gray calcite-baryte rock (fig. 8), ferruginous dolomitic rock, and silicified carbonate rock (Olson and others, 1954). All phases of the stock contain bastnäsite. Age determinations indicate that the Sulphide Queen carbonatite was emplaced 1375±5 million years ago (DeWitt and others, 1987), about 25–35 million years after the alkaline igneous intrusions in the district (Castor, 2008).

Other Regions, Features and Areas containing this locality

References