The removal of coal ash from unlined pits near Duke Energy’s Sutton Steam Plant is one step closer as a result of action by the N.C. Department of Environment and Natural Resources announced Thursday afternoon.

DENR has approved water quality certifications for use of the coal ash to fill open pit mines in Chatham and Lee counties, the agency announced in a news release. Coal ash from Sutton, as well as from other hazardous locations, will be used at both the Brickhaven No. 2 Tract “A” mine in Moncure and the Colon mine in Sanford.

DENR spokeswoman Crystal Feldman said Thursday that the project is termed a coal ash reuse because the material will be used as structural fill in the open-pit clay mines, once the mines are lined to prevent the coal ash from leaching and contaminants from reaching groundwater. When the fill is hard, the surface can be built upon, she said.

Now that the water quality certifications have been issued, Duke Energy must obtain a federal permit that regulates the discharge of dredged or fill material into U.S. waters, including wetlands. That permit application, according to the release, is currently under review by the U.S. Army Corps of Engineers.

Duke Energy is under pressure from DENR to remove the coal ash from the area around the Sutton Plant. In March, it levied the state's largest-ever penalty for environmental damage - $25 million - against the utility company for alleged water quality impact over a period of time. Duke has contested the penalty.

Early last month, the utility announced two initiatives at the Sutton Plant: it would begin dismantling the plant's iconic smokestacks, remnants of its coal-burning days, and would move ahead with plans to remove the coal ash as soon as permits were obtained.