There are 17 minerals that are considered rare earth elements. They are used primarily in small amounts in high-technology products and by the military. Usually, only one or two rare earths are found in mineable quantities in any particular mineral deposit. Researchers are looking for alternatives and developing recycling technology, so the demand for rare earths should go down in the long run. Still, there is a lot of exploration currently going on worldwide to find more sources of rare earth elements, because China has limited access to the rare earths it mines.
Each rare earth element requires different chemical processing before it can be used to make products. The particular element must be 99.99% pure. The chemistry is very complex, and there are anywhere from dozens to hundreds of steps in the purification process, each with its own waste stream.
Rare earths are not found alone. According to the U.S. Geological Survey (2010), "The ores of rare earth elements are mineralogically and chemically complex and commonly radioactive. The principal deleterious impurity in REE-bearing minerals is thorium, which imparts an unwanted radioactivity to the ores." Rare earth elements, in other words, leave radioactive wastes, just like uranium mining.
The three largest known mineable deposits of rare earths in the United States are at Mountain Pass, CA (pictured), the Bokan Mountains in Alaska, and the Bear Lodge Mountains in Wyoming, about six miles northwest of Sundance off Highway 14.
A Canadian company named Rare Element Resources wants to dig an open pit mine at the Bear Lodge deposit, which may also contain gold. The Bear Lodge deposit contains more thorium, a radioactive mineral, than most rare earths deposits. The company admits that rare earths deposits are "environmentally challenging due to thorium content." The thorium could either be processed and used, or left as wastes.
Rare Element Resources has a permit to explore on 200 acres at Bull Hill. It has 80 federal claims, plus a state lease. There's lots of other rare earth element exploration in the area.
If Rare Element Resources can get the necessary permits, its mine would last 15 years. The ore may be shipped to California for processing, which would put a lot of radioactive materials on our roads. The company is currently doing a "preliminary feasibility study," which is due in early 2012. If everything goes very smoothly, the company says it hopes to start mining in 2015.
There is an additional concern at the proposed Bear Lodge project. An old nuclear reactor is at the project site. No mining or blasting is allowed near the old reactor, due to safety concerns. But the buffer zone for the reactor goes to within 1,000 feet of the Bull Hill site.
Rare earth elements mining may become a regional issue. They are found at high levels in other locations around the Black Hills.
If mining were to start at the Bear Lodge site, it would compete with ranching, hunting, timbering, and current water users. It would also negatively impact cultural and historical sites. Twenty Native American tribes have a link to Devil's Tower (Bear's Lodge), which is about 12 miles away.
Most rare earths are somewhat toxic, although their impacts have been poorly researched. As noted above, the major wastes from REE mining are radioactive. There are also processing wastes, such as acids from leaching, mercury, lead, benzene, caustics, and corrosives. In China, to make one ton of rare earth oxide, there are 63,000 cubic meters of waste gas (sulfuric and hydrofluoric acid), 200 cubic meters of acid-containing sewage water, and 1.4 tons of radioactive waste.
At other rare earths mines, there have been a number of problems. The Mountain Pass mine on the California-Nevada border is the largest rare earths mine in the United States. It closed in 2002, partly due to environmental problems, but plans to reopen. The mine is a 55-acre pit that is 500 feet deep. The waste ponds are leaking and have polluted an underground water source. Spills at the site included 600,000 gallons of thorium-laced water and another two-million gallon spill. Groundwater that pours from the mine is contaminated with radium, thorium, and strontium, and there have been allegations of illegal nuclear waste dumping.
In Illinois, the Kerr-McGee company had four rare earths sites. All are now Superfund sites - among the most contaminated sites in the country. Seven miles of creek, a sewage treatment plant, and downstream areas were contaminated.
China, where most rare earths mining has been occurring, has stopped exporting rare earths. This means that manufacturing that uses rare earths must be done in China. This has driven the current growth in exploration in other locations.
Developing a rare earth element mine is difficult and expensive - ten times as expensive as developing a normal open pit mine. But because only a small amount of each element is used in each type of manufacturing, we don't need a lot of rare earths mines. The first few mines that begin production will meet world demand for some time. As one mining researcher put it, "85% of the [rare earths] activity is 95% hype," and most exploration will never lead to a mine. The need for new mines has been minimized even further, because the Mountain Pass mine is due to reopen in 2012.
There is another problem in getting a rare earths operation up and running. This is that, outside China, the very specialized knowledge needed to mine and process rare earth elements is limited. Few people know how to do this type of mining and processing - much less how to do it safely.
As a mining commentator (Mineweb, 2011) put it, "This author believes no junior REE miners will be able to produce a rare earth permanent magnet - or the high purity metals, alloys and powders used in manufacturing high tech devices." Rare Element Resources is a "junior" - or small and new - mining company.
So it is quite possible that there will be no need for the Bear Lodge mine. And it is likely that such a small company will not have the expertise to produce usable rare earth elements. But the company has a motivation to get the mine dug anyway - it would make money for the people who work for the company. This makes it imperative that we make it clear that we oppose the project now. If mining does start, and then there's no demand for rare earths, our area will be scarred and polluted, and our local economy will be disrupted by a project that's not needed.