The downward slide continued for Colorado's coal industry in 2015, highlighted by production at Routt County's Twentymile Mine, which was down 38 percent. Statewide, production in Colorado was down 18.5 percent, with 18.7 million tons, the lowest amount of coal mined in 23 years. ... Colorado Mining Association President Stuart Sanderson said the drop in production is a result of lower demand, but it was not caused by natural market forces. What we are seeing is the direct result of government regulations that are designed to drive coal out of the energy mix," Sanderson said. He called Colorado's 2010 Clean...