In the middle of California's Mojave Desert about an hour outside of the Las Vegas strip, business is booming -- literally -- as detonations reveal the lifeblood of America's technical security. Molycorp has begun mining again at its Mountain Pass facility after about a decade of inactivity, extracting valuable and concentrated ore that holds 15 rare earth elements, used in everything from cell phones to U.S. missile systems. In recent years, the Chinese have flooded, and thus cornered, about 97 percent of the world market of rare earth metals, and now thanks to high-tech demand and new Chinese restrictions on...