It makes sense but I think Tesla would need a mining company as a partner just as they need Panasonic as a partner, because they do not have the technology or knowhow to make their own batteries. But a 3 way tie up with Tesla/Panasonic/ and a miner like Glencore/RioTino/BHP etc makes a lot of sense. The only question is will a miner go along or will they want to make the big profits themselves operating the mine?