| Abstrakt: |
"Rare Earths in Alaska" was a conference held in Fairbanks in August 1988 to examine the economics of development of a rare-earth industry in Alaska. The meeting discussed a description of rare earths and their uses, ore location in Alaska, mining possibilities, extraction and purification, and worldwide market demand. The invited participants represented all technical and political groups required to comprehensively address the issue. This included Alaska's Division of Geological and Geophysical Surveys and Division of Mining; U.S. Geological Survey; U.S. Bureau of Mines; the University of Alaska; Alaska Pacific University; recognized international industrial suppliers of rare earths such as Molycorp and Mitsubishi Research Institute; Alaska miners; mining and extraction engineers; geologists; and consultants from outside Alaska. The meeting posed two questions: Is it viable to try to develop this industry in Alaska at this time? What recommendations should be made in light of the resources definitely known to exist in Alaska? The rare-earth elements, usually considered to include scandium, yttrium, and the lanthanides, are a group of fifteen metals with rather similar properties. Although rare-earth elements are found throughout the world, rare-earth deposits have been commercially developed at only a few sites, primarily in California, China, Australia, and Brazil. The main commercially known ores are bastnáesite (a carbonate), and monazite and xenotime which are phosphates. They occur in placer deposits and beach sand and in igneous forms along with titanium, tin, uranium and thorium, and other elements. Materials from these mines are processed in the U.S., Europe, and Japan, and ultimately find their commercial use in products such as alloys for steel, chemicals, petroleum catalysts, additives in glass and ceramics, optical enhancement, color phosphors for television screens, or in electronic components. Yttrium achieved recent notoriety for its use in high-temperature superconducting materials. Neodymium is essential for high-strength magnets . Several features of the rare-earth industry make it rather unique. The rare-earth deposits, without exception, consist of mixtures of most rare-earth elements. Because of their chemical similarities, the tedious and costly purification and separation of anyone rare-earth metal from the ore produces other purified rare-earth metals as by-products. Commercial grades of rare-earth products include ore concentrates, mixed metals, compounds, pure oxides, and pure metals. Thus industry must market all fifteen rare-earth elements, even though some are inherently more valuable and profitable than others. Furthermore, the total market for rare earths (approximately 50,000 metric tons of rare metal oxide ore in 1985) is small, and demand for specific metals is volatile. These factors have created an industry dominated by just a few international corporations which produce most rare-earth ore as a by-product of other mining. To date, Alaska has not been involved in the rare-earth industry in any way. However, the state is a large potential supplier of all rare earths. Based on the limited mineral survey work conducted to date, approximately one dozen Alaska sites in the southeast and interior portions of the state are known to have potential as commercial rare-earth deposits. Alaska deposits occur in four main areas: 1) placer and beach sands in the areas near Old Crow; 2) placer sands and intrusions in the Darby Mountains, Selawik, Purcell Mountains, and Death Valley; 3) the Yukon/Tanana terrane of the Steese-White Mountain and Healy-Dexter Creek areas; and 4) the carbonatite deposits at Bokan Mountain, Prince of Wales Island and Salmon Bay in southeastern Alaska. Bokan Mountain in southeast Alaska is the best example studied (with estimated reserves of 40 million tons of ore containing 0.5 to 1.0 percent rare earths), and has generated interest among corporations dealing in rare earths (although there has yet been no move toward development). Generally, the known Alaska deposits seem to have higher concentrations of heavier rare-earth elements such as yttrium than do most present commercial ores. This is an advantage; there is little competition from producers in the lower United States. At the same time there is a disadvantage since the relative lack of these heavy elements from commercial ores has retarded the development of methods for isolating and purifying them. Also, the industry has not been prompted to invent many commercial uses for them. [ABSTRACT FROM AUTHOR] |
