ST. LOUIS (AP) — Arch Coal Inc. swung to a second-quarter loss on mine closures and weak demand, but it did much better than Wall Street had expected and shares finished the day up 29 percent.

A soured global economy has cut into demand for coal, but so has cheap natural gas, an alternative fuel. Utilities are switching to natural gas from coal to generate electricity. Natural gas prices are the lowest in years because of huge supplies from booming production, and the mild winter across much of the nation didn’t put much of a dent in supply.