WASHINGTON -- New rules limiting emissions from power plants are set to be released Monday afternoon, but industry groups are already launching legal challenges to the standards.

The National Mining Association, which represents coal-mining companies, requested on Monday a stay on the implementation of the new rules, "while the courts have the opportunity to determine the lawfulness of the agencys attempt to commandeer the nations electric grid."

The power plant rules, details of which were released over the weekend, deal with greenhouse gas emissions from both new and existing power plants. They aim to cut emissions from the nation's current fleet of power plants 32 percent by 2030, and to prevent new power plants from being built unless they come with emission-capturing technology.

The rules will have the greatest impact on coal-fired power plants, which are responsible for about 40 percent of all U.S. emissions. President Barack Obama will formally announce the standards, which the administration calls the Clean Power Plan, during a press conference at a White House event at 2:15 p.m. Monday.

"[T]he Rule, as you yourself have described it, aims at nothing less than the comprehensive 'transformation' of the American electric power grid," wrote Hal Quinn, the NMA's president and chief executive officer, in a letter to Environmental Protection Agency head Gina McCarthy . "Congress, however, did not give EPA the power to restructure how the nation produces and consumes electricity."

Implementing the rule, Quinn wrote, "will irreparably injure the coal mining industry, coal mining workers, and coal mining communities" and "has no purpose other than to reduce the use of coal for electric generation as a means of reducing power sector [carbon dioxide] emissions."

Murray Energy Corporation, the largest underground mining company in the United States, also signaled its intent to file five separate legal challenges to the power plant rules, which they described as "flagrantly unlawful."

"In promulgating this so-called Clean Power Plan, the Obama administration has ignored the voluminous input clearly demonstrating the illegality and impracticality of the Rule, and failed to make necessary changes," the company said in a statement.

Legal challenges to the rules have been widely anticipated. Industry groups already tried to challenge the draft version of the rule, which was released in June 2014, but the Court of Appeals for the District of Columbia Circuit threw out the suit earlier this year, finding that the challenge was premature because the standards had not yet been finalized.

A number of states have also indicated that they intend to challenge the new rules.

Environmental groups, meanwhile, signaled during a call with reporters on Thursday that they are preparing their defense of the rules.

"I've seen many new EPA standards during my career, and virtually every major new standard that advances public health gets challenged. So, it will be no surprise and maybe not even newsworthy when the polluters and their allies file their lawsuits," said David Doniger, director of the climate and clean air program at the Natural Resources Defense Council. "No matter how many cases are filed and how many press releases are issued, the legal attack is likely to fail."