The Environmental Protection Agency has imposed new curbs on the mining practice of mountaintop removal. On Thursday, the EPA said it will no longer allow coal companies to fill neighboring valleys with the rubble from destroyed mountain peaks. EPA Administration Lisa Jackson cited evidence showing so-called “valley fills” pollute surrounding mountain streams. Coal mining companies say the new regulations could bring their operations to a halt. Luke Popovich of the National Mining Association said the new rules are “tantamount to saying the intent is to strictly limit coal mining in Appalachia.” The regulations, however, will only apply to new mining permits, not existing operations. Amanda Starbuck of the Rainforest Action Network said, “The EPA has confirmed what science tells us, that mountaintop removal is harming water resources and public health in real and measurable ways, which is why these new guidelines should apply to existing mining permits — not just new ones.”