The US Mine Safety and Health Administration said it was the coal mining industry’s 19th fatality this year.
CONSOL has devised a plan for divers to find the dozer.
Investigators did not indicate what might have caused the 650-foot embankment at the mine’s coal treatment plant to give way.
The agency called the collapse a “massive failure”
“A section of the saddle dam measuring approximately 650 feet long, 20 to 25 feet above the water's surface, and 70 feet back from the water's edge, broke and slid into the impoundment,” MSHA officials said.
It said four workers were in the area when the embankment gave way and three of them went into the water with their equipment – two pickup trucks and a bulldozer.
“Two miners were standing near the face of the saddle dam looking over and recognized a failure was about to occur. They began to run but were pulled into the water,” MSHA confirmed.
Following the incident, one of the miners swam to shore and another was rescued by the local fire department.
CONSOL spokesperson Lynn Seay told ILN that it had received approval to resume use of the slurry pond for operation of the Robinson Run longwall machine and preparation plant.
“The decision to resume longwall and preparation plant operations at our Robinson Run mine will not interfere with the impending recovery efforts,” she said.