(October 1) The operator of the United States’ only rare earth mine has made a major improvement to its operation that is anticipated to return it to the forefront of worldwide lanthanide production.
Until 1948, most of the world’s rare earth minerals were mined in India and Brazil. In the 1950s, South Africa became the leading supplier of rare earth metals.
In 1949, the Mountain Pass Mine, which lies in the extreme northeast portion of San Bernardino County roughly 15 miles from the California-Nevada state line, was discovered by a uranium prospector.  The Molybdenum Corporation of America bought the mining claims, and small-scale production began in 1952. Production expanded greatly in the 1960s, with the Mountain Pass facility becoming the world’s dominant producer of rare earth elements, also known as lanthanides. From 1965 until 1995 it was an almost exclusive supplier of europium, which is used in color television screens. The Molybdenum Corporation of America changed its name to Molycorp in 1974 and was acquired by Union Oil in 1977.
After the company was acquired by Unocal, ruptures in a pipeline conveying wastewater from the mining operation to evaporation ponds at Ivanpah Dry Lake resulted in thorium and radium leaking into the desert floor and the mine was shut down in 2002. As a consequence of the closure, China eclipsed the United States as the leading supplier of rare earth metals. After Unocal in 2004 obtained a new operating permit for the mine, it was acquired the following year by the Chevron Corporation.
By 2005, 96 percent of the world’s rare earth elements were mined in China. In 2007, China restricted exports of rare earth elements and imposed export tariffs. In 2008, Chevron sold the Mountain Pass Mine to privately-held Molycorp Minerals LLC, based in Greenwood Village, Colorado, a company formed to revive the Mountain Pass mine. After redressing all of the environmental issues at the operation to the government’s satisfaction, on July 29, 2010, Molycorp, Inc. became a publicly-traded firm by selling 28,125,000 shares at $14 in its initial public offering of stock.  On September 22, 2010 China enacted a ban on exports of rare earths to Japan. That fall, Congress passed legislation to subsidize the revival of the American rare earths industry, including the reopening of the Mountain Pass mine.
Molycorp acquired processing facilities in Arizona and Estonia and Canada.
At Mountain Pass, the company has built an on-site combined heat and power plant, which is now providing  low-cost, high-efficiency electrical power and steam for the company’s extraction of heavy rare earth concentrate ore.
This week the company announced it has significantly expanded the leach system at the mine, including its retention capacity. While operations of the new leach system are expected to be limited in the near term due to constraints in onsite production and market availability of hydrochloric acid, company officials said that the system expansion addresses one of the major production bottlenecks at Mountain Pass and is expected to boost rare earth production and lower operating costs once it is fully operational and sufficient supplies of hydrochloric acid are available.
While onsite production and market availability of hydrochloric acid are expected to improve in the fourth quarter of 2014 and beyond, company officials said that third quarter rare earth production at Mountain Pass is not expected to exceed first quarter 2014 levels.
Company officials also announced that the onsite chlor-alkali facility at Mountain Pass, which uses process waste water to produce hydrochloric acid and other chemical reagents used in rare earth production, is operational and that its output is expected to increase as facility engineers continue to make equipment repairs and address quality issues related to the brine feedstock that have been impacting the plant’s operations.
“Expanding our leach system is a significant step in our efforts to increase rare earth production over the coming months at Mountain Pass and to continue to reduce our operating costs,” said Geoff Bedford, Molycorp President and Chief Executive Officer.  “We remain committed to meeting our customers’ needs by building a global, vertically integrated company that produces rare earth materials in an environmentally superior way and at a cost that is competitive with any other producer in the world.”