BRICEVILLE, Tenn. (AP) — Mining regulators responding to a discharge of partially treated coal cleaning wastewater in the New River in East Tennessee have sent a notice of violation letter to Premium Coal Inc.

The Tennessee Department of Environment and Conservation issued the Monday letter in response to a Jan. 3 discharge of partially treated coal process wastewater and coal slurry that includes chemicals used in the washing operation in the Devonia community of Anderson County.

The operation remains shut down. No drinking water operations are affected, although there were reports of a black water pollution "plume" more than 28 miles away, said agency spokeswoman Meg Lockhart.

Premium Coal's chief engineer in Briceville, Derrick O'Neal, declined to comment when contacted by telephone Tuesday.

The discharge originated from a pipe in the company's Gum Branch Slurry Impoundment and was not reported within 24 hours as required, according to the notice letter signed by Dave Turner, an environmental specialist with the mining section of the state agency's water pollution control division. The letter also says the company failed to quickly start collecting discharge water samples.

Permit records show there have been violation notices in previous years.

Lockhart said the notice is a "first step" in its investigation with the federal Office of Surface Mining, which the notice said issued an order to cease operations following a citizen complaint about the discharge.

The notice orders the company to continue collecting daily samples and provide detailed water analysis within 30 days.

The company in a Jan. 13 report said that about 1.4 million gallons of the water "left the impoundment" and an undetermined amount reached the river. Premium Coal's report said its managers "voluntarily idled the preparation plant," and have since been taking corrective action.

Environmental activist Patrick Morales, a member of the board of Statewide Organizing for Community Empowerment, said "more than 1 million gallons of toxic waste drained into the New River which flows to the Big South Fork National River and Recreation Area." Morales said the pollutants "include mercury, selenium, arsenic and all kinds of heavy metals."

He said there were reports of black water just outside the Big South Fork area.