Tim Maughan, writer for BBC: You may not have heard of Baotou, but the mines and factories here help to keep our modern lives ticking. It is one of the world’s biggest suppliers of “rare earth” minerals. These elements can be found in everything from magnets in wind turbines and electric car motors, to the electronic guts of smartphones and flatscreen TVs. In 2009 China produced 95% of the world's supply of these elements, and it's estimated that the Bayan Obo mines just north of Baotou contain 70% of the world's reserves. Mining produces a lot of hazardous waste. The United States has chosen to shut down many of its mines and let the rest of the world do the dirty work so we can have all our modern technology including wind turbines and solar panels.