SALT LAKE CITY (AP) — The Utah Supreme Court rejected arguments Tuesday that state regulators failed to assess the full environmental impacts of a coal mine outside Bruce Canyon National Park.

The high court turned back a challenge brought by the Sierra Club and other environmental groups that asserted the state ignored a host of drawbacks from a strip mine operating a dozen miles from a corner of the national park. Coal trucks rumbled through Panguitch, a town listed on the National Historic Registry, hundreds of times a day.

Regulators satisfied state law with a plan to monitor the Coal Hollow Mine for any water pollution that gets into local creeks, justices said part of their 22-page decision.

The Sierra Club and other groups took an appeal first to the Utah Board of Oil, Gas & Mining, which upheld the operating permit issued by state regulators. The high court Tuesday affirmed the board's decision.

Opponents said they were shifting their attention to plans by Alton Coal Development LLC for a larger coal mine expanding from private to public lands.

"We will continue to fight to preserve the water we drink, the air we breathe and the night skies at Bryce Canyon National Park enjoyed by thousands of tourists each year," said Steve Bloch, a staff lawyer for the Southern Utah Wilderness Alliance.

Added Josh Mogerman of the Natural Resources Defense Council, "A strip mine is not the sort of canyon tourists are flocking to see."

Alton Coal has been operating the mine on 440 acres of private land for more than a year and is seeking permission to expand on surrounding federal range lands.

The company, a group of investors from Florida and Colorado, received tentative approval for a 3,500-acre lease a year ago from the U.S. Bureau of Land Management. The BLM said it would take a second look over objections filed by the U.S. Fish & Wildlife Service, National Park Service and the U.S. Environmental Protection Agency.

Federal biologists say the larger mine will wipe out the southernmost population of sage grouse. The Park Service objects to the dust, nighttime lights and machinery noise of around-the-clock mining in an area so quiet that measuring devices fail to register natural sounds.

The EPA said the coal mining would muddy local creeks and release methane, a greenhouse gas the EPA says is 20 times more potent than carbon dioxide.

The Utah Supreme Court didn't rule on the larger mine, saying only that regulators were justified in approving mining on the smaller private parcel.

Utah officials favor a larger strip mine. Local officials say it will create at least 240 jobs and provide $1.5 billion in economic benefits to Garfield and Kane counties over 30 years.

"This is simply the wrong place and the wrong time for another coal mine," said Tim Wagner of the Utah Chapter of the Sierra Club. "We should be investing in clean, responsible energies instead of doubling down on old, dirty, fossil fuels. BLM should do what is best for Southern Utah rather than what is best for one private company."