The United States has exported the dirtiest businesses internationally for quite a few years (raw mineral extraction is a dirty, nasty business, with slim margins). Now that China has become more adversarial and also more established (you mean people want to actually get PAID to slave away in a mine, or even worse, refuse to even work in a dangerous and dirty pit mine?!) the US is facing some hard decisions. We need many of these materials, and we have them, but we haven't had the will to mine them. Lots of people want to open US government lands to these resource extraction outfits, but there's right worry about the potential for ecological destruction.