Elon Musk promises a “giant contract” with the miner that can supply nickel for Tesla Inc. batteries at low cost with minimal environmental impact, yet the industry’s messy track record may make that deal difficult to clinch. Recent accidents such as a diesel spill in Arctic Russia and a burst waste pipeline in Papua New Guinea suggest the industry will struggle to meet Musk’s request for a large quantity of the metal produced in an “efficient” and “environmentally sensitive” way.