From Erika Bolstad in Washington D.C. --

In a closely watched environmental case, the U.S. Supreme Court has decided 6-3 in favor of Couer Alaska Inc., which seeks to reopen the Kensington gold mine near Juneau. The court ruled Monday morning that the company's permit to discharge slurry from its gold-mining operation was not only lawful, but that the permit was appropriately issued by the U.S. Army Corp of Engineers.

Environmentalists had objected to the company's proposal to dispose of tailings from gold mining into Lower Slate Lake in the Tongass National Forest.

The Corps of Engineers issued a permit giving the go-ahead for dumping after the corps and the Environmental Protection Agency agreed to a regulatory change in 2002. That rule change redefined "fill," according to one of the parties in the case, Earthjustice. That meant almost any solid material, including waste and contaminated materials, could be dumped into waterways. In Kensington's case, the Bush administration expanded its interpretation of the rule to allow dumping of toxic, industrial wastewater slurries directly into lakes and other water bodies, Earthjustice said, a practice that had long been prohibited by EPA rules.

An appellate court invalidated the permit, saying the dumping is barred by the EPA's pollution-control requirements under the 1972 Clean Water Act. Since 1982, it has been illegal for new gold mines using a particular mining process to discharge waste into navigable lakes or rivers.