The 1983 rule prohibited dumping the fill from mountaintop removal mining within 100 feet of streams. In practice, the government hadn't been enforcing the rule. Government figures show that 535 miles of streams were buried or diverted from 2001 to 2005, more than half of them in the mountains of Appalachia. Along with the loss of the streams has been an increase of erosion and flooding.

The 11th hour change before President George W. Bush leaves office would eliminate a tool that citizens groups have used in lawsuits to keep mining waste out of streams. Mining companies had been pushing for the change for years.

It also means that President-elect Barack Obama's administration will have to decide whether to try to restore and enforce the rule, a process that could take many months of new rulemaking. Obama's transition team declined to comment on its plans on Tuesday...

For now, however, the EPA's approval means there are no further obstacles to the Office of Surface Mining's plans to change the rule. The White House's Office of Management and Budget approved it on Monday. The Department of Interior, which includes the mining office, plans to make the rule final in December after briefing members of Congress, and it will go into effect 30 days after that, said spokesman Peter Mali.