China sent the high-tech industry and markets reeling last fall when it blocked exports of raw rare earth minerals to Japan, Europe and the U.S. The sudden severing of rare earths supply was a frightening prospect as the minerals are key ingredients in a broad range of high-tech products, from smartphones to wind turbines and hybrid cars. Although the bans have since been lifted, governments around the world saw the ban as a kind of wake-up call and started looking at ways to develop their own mineral resources - for rare earths as well as basic industry metals like copper and zinc.