FRANKFORT — Environmental groups say one of the state's leading coal companies has submitted an additional 5,000 possibly false water pollution discharge reports.

The environmental groups — Kentucky Riverkeeper, Kentuckians For The Commonwealth, Appalachian Voices and the Waterway Alliance — are threatening to sue the company Nally and Hamilton for the second time this year.

The groups sued in May over 12,000 alleged violations from 2008 to 2011.

The groups then decided to go back to 2006 and 2007 to look at Nally and Hamilton's discharge monitoring reports and found the additional 5,000 alleged violations.

The groups also have an ongoing lawsuit in Franklin Circuit Court against ICG and Frasure Creek over similar false reporting allegations.

The reports sent to state authorities by Nally and Hamilton included the same data in discharge reports month after month. The groups allege that it appears the data was "copy and pasted" from previous reports. Legally required information was also missing, the groups say.

"In the last 10 months we uncovered more than 41,000 Clean Water Act violations from three coal companies in Kentucky," said Donna Lisenby, director of water programs for Appalachian Voices.

"With the filing of this fourth notice of intent to sue, it is undeniable that there is a clear pattern of Clean Water Act violations and yet no one in any government agency discovered these violations or brought enforcement action until we exposed the blatant lawlessness."

But Bruce Scott, the commissioner for the Department of Natural Resources, denied the groups' accusations, saying the department has issued administrative proceedings against Nally and Hamilton over the 12,000 previous violations and intends to issue more citations.

The state allows coal companies to discharge a limited amount of water pollutants in the water. However, the companies are supposed to submit water testing data to the state so it can be monitored for high levels of pollutants.

Under the federal Clean Water Act, the company has 60 days to respond to the allegations and correct any problems. If those alleged improprieties are not corrected and the state does not take action, the environmental groups can sue Nally and Hamilton in federal court.

Jack Bender, a lawyer for Nally and Hamilton, said he could not comment because he had not seen the notice.

Nally and Hamilton is the fourth largest surface mining company in Kentucky.