The pay dirt has run out for gold miners in California. Last week the state mining board okayed the nation’s toughest regulations on open-pit metallic mining, requiring companies to refill mining pits and flatten waste piles in order to restore the landscape to at least some semblance of its pre-mining state. The industry complains that the new rules will be so costly that mining companies simply won’t do business in the state, and some are threatening to sue. “This ends it,” said Adam Harper of the California Mining Association. “The cost of backfilling is such that it will simply make it not economically viable to mine any deposit in California.” This could be the deathblow for a controversial gold mine proposed within view of Death Valley National Park and another operating near a sacred Native American site. No word yet on when enviros will be holding good-bye parties for the mining execs.