by Tom Hamburger and Peter Wallsten

WASHINGTON - With the election of Barack Obama, environmentalists expected to see the end of the "Appalachian apocalypse" -- their name for exposing coal deposits by blowing the tops off of whole mountains.

But in recent weeks, the Obama administration has quietly decided to open the way for at least two dozen more "mountaintop removal" projects.

The decision to clear a path for the controversial projects was never officially announced, but instead conveyed in a letter this month to a West Virginia congressman and coal ally, Democratic Rep. Nick Rahall. The letter said that the Environmental Protection Agency would not block 42 of 48 mine projects that it had reviewed so far, including some of the most controversial mountaintop mines.

In mountaintop removal, explosives blast away a peak and expose coal seams. Coal companies say the practice is safer and more efficient than traditional shaft mining. Critics say the process scars the landscape and dumps tons of waste, some of it toxic, into streams and valleys.

The administration's decisions are not the final word on the projects -- or on the future of mountaintop removal -- but it removes a major obstacle. And the decision, coupled with the light it sheds on relations between the mining industry and the Obama White House, has disappointed environmentalists. Some say they feel betrayed by a president they thought would end or sharply limit the practice.

What makes the issue politically sensitive is the fact that environmentalists were an active force behind Obama's election, while his standing among Democratic voters in coal states is tenuous. Halting mountaintop removal could eliminate jobs in those states and put upward pressure on energy prices.

Coal advocates have solicited help from officials as high as White House chief of staff Rahm Emanuel, and the issue sparked contentious debates among administration officials, including one shouting match in which top officials of two government agencies were heard pounding their fists on the table.

The White House is "searching for a way to walk this tightrope," said Phil Smith, a spokesman for the United Mine Workers of America, whose president, Cecil Roberts, has urged administration officials to allow the procedure. "They have a large constituency of people who want to see an immediate end to mountaintop removal, and an equally large constituency -- many of them Democrats, I might add -- whose communities depend on those jobs."

Earlier, Obama had won praise from the green lobby for taking a skeptical view of the procedure. And the EPA announced in March that it would review mountaintop projects.

The EPA has the authority to review and ultimately block mountaintop removal under the Clean Water Act, but if the agency raises no objections, the final decision is made by the Army Corps of Engineers. The corps previously indicated its intention to approve the 48 permits.

A review of Obama campaign statements showed the presidential candidate expressing concern about the practice without specifically promising to end it. On a West Virginia visit, he said he wanted "strong enforcement of the Clean Water Act" and added, "I will make sure the head of the Environmental Protection Agency believes in the environment."

And EPA Administrator Lisa Jackson said this year that the agency had "considerable concern" about the projects. She pledged that her agency would "use the best science and follow the letter of the law in ensuring we are protecting our environment."

Soon afterward, the agency blocked six major mountaintop projects in West Virginia, Kentucky and Ohio.

But this month, after White House meetings with coal companies and advocates such as Rahall and West Virginia Gov. Joe Manchin, the EPA gave the green light to at least two dozen projects.

"It was a big disappointment," said Joan Mulhern, a lawyer for Earthjustice, an environmental law firm that has led court challenges to mountaintop removal.

Mulhern charged that the EPA "blew off" Jackson's earlier promises that the agency would adhere to science and conduct an open process.

Ed Hopkins, a top Sierra Club official, said that some of the projects that obtained the EPA's blessing "are as large and potentially destructive as the ones they objected to.

"It makes us wonder what standards -- if any -- the administration is using."