LEADVILLE -- To outsiders, the amber hills of piled up mine waste, or tailings, that mark the countryside here are just part of the dramatic mountain scenery. But they're the subject of a new round in a long conflict between historic preservationists and environmentalists. To some long-time Leadville residents and state preservationists, the tailings piles are a valuable part of a distinct local history, a symbol of the great gold and silver booms of the past. To the U.S. Environmental Protection Agency, though, they are poison, the refuse of a century and more of industrial extraction that, despite decades spent on clean-up efforts, is still leaching heavy metals like zinc and cadmium into area water, putting the Arkansas River and downstream communities and wildlife at risk.