Mountain Pass, California, November 15, 2010 - In the distance, retrofitted snow blowers blast out fine mist to cover the hills of overburden to keep it from blowing into the air at the open pit rare earth mine at Mountain Pass. Overburden - also known as waste rock - are the materials lying over ore or mineral bodies that must be removed to access the ore but are not themselves processed. The overburden is removed from the mine and stacked nearby, usually closeby, to minimize the expense and time in transporting it. The water helps to keep the dirt from becoming airborn. Rare earth elements - there are 17 in all - are crucial for many current technologies, including mobile phones, wind turbines, hybrid cars, laptops and military hardware, such as Army tank navigation systems and Navy radars. Uranium prospectors discovered the mine at Mountain Pass in 1949 and it became the dominant producer of rare earth elements until the 1990s when pressure from other producers began to drive prices down. That along with a number of leaks of radioactive water during transmission into a evaporation lake 13 miles away and state regulators delaying operating permits forced the mines closure in 2002. Though mining ceased, some processing of already mined elements continued. Molycorp was purchased by Unocal in the 1970s, which in turn was purchased from Chevron. In 2008 it's long-time chief executive, Mark A Smith, purchased in from Chevron with the help of several private equity firms. The company raised $500 million in an effort to reopen the mine, which will include expanding and modernizing the current facilities as well as incorporating newer technologies to make mining the radioactive material more environmentally safe and adding a natural gas power plant to help reduce its need to buy more expensive and less reliable energy from Los Angeles. .