Pollution-monitoring reports that a coal company gave the state to correct earlier false data also contained false information, several citizens groups have charged.
A review of the corrected reports from Frasure Creek Mining found that 25 percent of them showed a lower amount of one type of pollution than what the raw laboratory data showed, the groups alleged.
In those cases, the company's report did not show a violation of pollution limits, but the lab data did, the groups said.
Coal companies usually don't have to submit such lab data with pollution-monitoring reports, but state regulators required Frasure Creek to include it as they investigated an earlier complaint from the citizens groups.
Never miss a local story.
"Without the raw laboratory data, this kind of false reporting is virtually undetectable," Lauren Waterworth, one of the attorneys for the groups, said in a statement. "This analysis shows that without that raw data, no report from Frasure Creek can be trusted."
The allegations of more false reporting by Frasure Creek came in a notice released Thursday from several groups that they intend to sue the company and affiliate Trinity Coal.
Frasure Creek was once one of the largest surface-mining companies in Eastern Kentucky before a downturn in the industry and a 2013 bankruptcy.
All the company's facilities and mines in Eastern Kentucky are listed as idled or non-producing in a federal mining database, though it still has a duty to monitor sites mined earlier.
The groups that said they intend to sue Frasure Creek if it does not correct violations were Appalachian Voices, Kentuckians for the Commonwealth, Kentucky Riverkeeper, Waterkeeper Alliance and the Sierra Club.
The groups have been pushing for tougher enforcement against Frasure Creek for years. Environmental rules include a role for citizens to help check whether coal companies are following the law.
Coal companies must monitor pollutants such as iron and sediment draining from surface mines into streams and report the data to the state.
If pollutants exceed certain levels, the state can issue citations and require action to correct problems.
Appalachian Voices and the other groups charge that thousands of monitoring reports the company submitted since 2010 were false, many because they duplicated information from a previous reporting period.
It would be unusual for discharges from different times to be exactly the same, raising a question on whether the company had new tests performed as required.
Last fall, the citizens groups charged that they had found more cases of false reporting by Frasure Creek in the first three months of 2014.
In response, the state Energy and Environment Cabinet investigated and Frasure Creek submitted new reports to correct the ones it had first filed, the groups said in a news release.
However, some of those included false information as well, according to the notice.
In addition to reports not matching lab results on which they should have been based, some new reports showed there was drainage from mined sites when the originals said there was none, the notice alleged.
The new reports that had accurate information showed the originals had covered up more than 600 instances in which Frasure Creek exceeded pollution limits, according to the groups.
"In the corrected reports, we now see numerous effluent violations where originally there were none," said Mary Cromer, an attorney with the Appalachian Citizens' Law Center who also represents the groups.
Attorneys for Frasure Creek did not respond to a request for comment. The company denied similar allegations in a federal lawsuit the citizens groups filed earlier this year, which is pending.
The groups have been critical of state oversight of Frasure Creek, arguing regulators did not notice widespread violations by the company before citizens documented alleged false reports or crack down hard enough on the company after the problems came to light.
However, cabinet spokesman Dick Brown said regulators found "numerous violations on which we have acted."
The Department for Environmental Protection felt the information it documented was sufficient to make its case against the company, but is reviewing additional alleged violations, Brown said.
Franklin Circuit Judge Phillip J. Shepherd last year rejected the state's proposal for a settlement with Frasure Creek in the case resulting from citizens' original 2010 claims about false reporting.
That deal called for the company to pay $310,000 for violations at more than three dozen mines.
However, Shepherd said the state did not investigate the likely environmental harm from the company's conduct and failed to consider the extent of the violations and the potential danger to human health and the environment.
He ruled the settlement was not adequate.