The Kentucky surface coal mine where two workers were killed by falling rock was cited earlier this year over the stability of a highwall.
Investigators say the men were killed Friday when a pile of rock crushed their truck as they drove near a highwall.
U.S. Mine Health and Safety Administration records show the agency cited operator Armstrong Coal in April.
Bob Gunnell, a spokesman for Armstrong, says the citation was for an unrelated incident that took less than an hour to correct.
The citation for the Equality Mine at Centertown refers to standards that require removal of loose hazardous material from the top of highwalls, which are the unexcavated faces of the layers of soil, dirt and rock lying on top of the coal seam.