WASHINGTON—The Bush administration is escalating a conflict with congressional Democrats over their efforts to block uranium mining claims near the Grand Canyon by planning to adopt a rule that could undercut Congress's power to prevent mining on public land.

The move by the Bureau of Land Management—an agency of the Interior Department that manages 258 million acres of land nationwide–marks the second instance this week in which the Bush administration has delivered a policy victory to mining interests. On Tuesday, the Environmental Protection Agency approved a proposed rule that would allow mining companies to dump waste near streams, despite objections from environmentalists and the governors of Kentucky and Tennessee about the proposal's potential impact on waterways.

The rule to be adopted Friday rescinds a regulation that requires the Interior Department to withdraw land from mining and oil and gas development when either of two congressional panels determines that an emergency exists and that "extraordinary measures" are needed to protect natural resources. A spokesman for the Interior Department, Chris Paolino, played down the significance of the rule change, noting that a provision in a 1976 law still requires the agency to withdraw public land from mining claims when ordered to do so by congressional oversight panels.

The agency's move drew an angry response from Rep. Raul Grijalva, an Arizona Democrat. "This last-minute change puts at risk the health of millions of citizens of the West who rely on the Colorado River of the Grand Canyon for their drinking water supply, as well as visitors to the Park and tribal communities within and around the Grand Canyon," Mr. Grijalva said in a written statement.

Groups that represent the mining industry have lobbied the Interior Department to throw out the regulation that allows congressional oversight panels to order emergency withdrawal, saying it created needless uncertainty. "This is a crazy quirk in the law that needs to be fixed," a spokeswoman for the National Mining Association said.

Write to Stephen Power at stephen.power@wsj.com