CHARLESTON, W.Va. -- Alpha Natural Resources will have to clean up selenium pollution at three of the mountaintop removal mines it bought from Massey Energy, under a legal settlement with environmental groups announced Monday.The Sierra Club said Alpha would spend at least $50 million on the cleanups, which cover the company's Twilight and Red Cedar operations in Boone County and the Kanawha Division along the Kanawha-Fayette County line.Alpha reached the deal with lawyers for the Sierra Club, the Ohio Valley Environmental Coalition and other groups to resolve a federal court lawsuit the citizens filed over repeated selenium violations.The settlement, which must receive approval from U.S. District Judge Robert C. Chambers, is the latest success by lawyers from the Appalachian Mountain Advocates in forcing major coal producers to deal with selenium pollution.Previously, environmental groups worked out a selenium settlement with Arch Coal and won a favorable ruling that requires Patriot Coal to install new treatment systems for selenium.Citizen groups and their lawyers have been pursuing actions over selenium pollution as scientists and federal regulators express concerns that mining discharges are threatening aquatic life.Selenium, a naturally occurring element found in many rocks and soils, is an antioxidant needed in very small amounts for good health. In slightly larger amounts, selenium can be toxic.Selenium impacts the reproductive system of many aquatic species, can impair the development and survival of fish and can damage gills and other organs of aquatic organisms subject to prolonged exposure.In 2003, a broad federal government study of mountaintop-removal mining found repeated violations of water-quality limits for selenium. The following year, a U.S. Fish and Wildlife Service report warned of more selenium problems downstream from major mining operations.Since then, coal lobbyists have tried unsuccessfully to weaken the state's selenium limits, but have persuaded the DEP to repeatedly delay compliance deadlines for many operations.In the Massey case, trial had been set to begin in August before Chambers, who had ruled in April to allow the citizen group suits to continue.Chambers had ruled that the then-Massey operations were violating selenium permit limits, and said further hearings would be held to decide the scope of injunctive relief and civil penalties. Those hearings were called off when lawyers told the judge they were close to a settlement.Under the settlement, Alpha will be given time to install certain types of treatment systems, but will have to upgrade those to more expensive technology if selenium violations don't stop. The deal calls for compliance with permit limits by mid-2014.Alpha will also pay $450,000 in civil penalties and contribute $4 million to the West Virginia Land Trust to help fund the West Virginia University College of Law's new Land Use and Sustainable Development Clinic.Reach Ken Ward Jr. at email@example.com or 304-348-1702.