SALT LAKE CITY (AP) -- Environmental groups said Utah regulators erred in approving a strip mine near Bryce Canyon National Park in arguments held Monday before the Utah Supreme Court.
Lawyers for the coal company and the Utah Division of Oil, Gas & Mining argued that they satisfied every requirement of law.
The Sierra Club and other environmental groups said Alton Coal Development LLC failed to properly address the environmental impacts of a strip mine operating for about a year about a dozen miles from a corner of the national park in southern Utah.
The opponents say regulators failed to consider the potential for groundwater pollution, or even how it will be measured.
They also accused the state of ignoring the coal trucks that rumble through Panguitch, a town listed on the National Historic Registry, hundreds of times a day.
Lawyers for Alton Coal told the Utah Supreme Court on Monday that the company is diverting runoff around the strip mine to keep sediment from muddying local creeks.
The mine keeps discharge water contained in mine pits, the lawyers said.
Justices for the Utah Supreme Court had few questions for the lawyers and didn't indicate when they might issue a decision. The court typically takes months to decide a case.
Although it's not at issue in the Utah Supreme Court case, the coal company is seeking a federal lease to expand onto surrounding public range land.
Alton Coal Development got its start mining 440 acres of private lands. The company, a group of investors from Florida and Colorado, received tentative approval last fall from the U.S. Bureau of Land Management to mine the larger range lands.
The BLM decision brought opposition from the U.S. Fish & Wildlife Service, the National Park Service and the U.S. Environmental Protection Agency.
It's unclear when the BLM will make a decision on leasing the coal tract. BLM officials in Utah didn't immediately respond Monday to a message left by The Associated Press.
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.
Federal biologists say the larger mine will wipe out the southernmost population of sage grouse. The National 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 also filed objections, saying the coal mining would muddy local creeks and release methane, a greenhouse gas the EPA says is 20 times more potent than carbon dioxide.