Natural gas plummeted to a new three-year low as heavy surpluses deepen a selloff. It is the latest leg down for a commodity that has struggled for years under the weight of a record-setting oil-and-gas boom. Production has hovered around all-time highs for about a year, which eventually became too much for prices that had managed to stabilize and outperform most other commodities for the past several months. Prices for the front-month November contract fell 9.1 cents, or 3.6%, to $2.433 a million British thermal units on the New York Mercantile Exchange. It is the largest one-day loss in seven weeks and the lowest settlement since June 13, 2012. Gas had managed to tread water this summer and even briefly hit a bull market in the spring because of surging demand from power plants that are switching away from coal. But in recent weeks that demand has subsided along […]