Mining companies have pledged $250 million toward a 30-year cleanup of contaminated "hotspots" in the Coeur d'Alene River Basin, Gov. Dirk Kempthorne announced. If accepted by the federal government and the tribe, the proposal would remove lead, cadmium and other wastes remaining from a century of mining activities in Idaho's Silver Valley. Federal agencies would be asked to contribute as much, if not more, Kempthorne said. In exchange for annual cleanup payments, the mining companies would be protected from litigation. A formal plan for public review is expected by the end of July. The tribe appears wary of the deal, but willing to support it. Kempthorne said he urged U.S. Interior Secretary Bruce Babbitt and Agriculture Secretary Dan Glickman to accept the plan and complete negotiations within 60 days. He said he also asked the tribe to participate in negotiations. The river flows through northern Idaho's Silver Valley into Lake Coeur d'Alene, the headwaters of the Spokane River. Under the agreement, chief executive officers of Hecla Mining Co., Asarco and Coeur d'Alene Mines Corp. pledged $154 million in actual payments, with the remainder coming from royalties pegged to the price of precious metals, Kempthorne said. A fourth company might also join, he said.