One of the world’s largest coal companies in terms of reserves, Arch has seen its stock slump some 99.7% in the past five years to 20 cents recently. That should be a more respectable $2 or so after Monday—but only because the number of shares will fall due to a reverse stock split . Big Coal is at once a faint shadow of itself yet still vital economically. Mainly used for power generation and metallurgy, the percentage of U.S. electricity from coal-fired plants recently fell to 30% , just below the share from natural gas, according to SNL Energy. Five years ago, coal had twice the share of gas at 44%. But years of cheap, abundant shale output and tightening environmental standards have led many utilities to shut coal plants. That shift hasn’t been enough to absorb the glut of North American gas, something that would be a relief […]