While official updates are growing scarce, US Mine Safety and Health Administration spokeswoman Amy Louviere told ILN the worker, whose name has not been released, was still unaccounted for but efforts were continuing.
Those searching for the bulldozer that sank into the murky impoundment last Friday at the mine near Shinnston, Harrison County, were using metal rods and sonar to pinpoint its location.
They said it was about 25 feet below the surface.
“The company is continuing to evaluate the best method to reach the bulldozer safely and determine its orientation – upright, on its side or upside down,” Louviere said late Monday.
“Dredging began at approximately 1.30pm to permit access of … four barges [that are] currently onsite.”
Louviere confirmed Monday afternoon that the two other workers involved in the incident escaped and were no longer under medical treatment.
“MSHA has issued a ‘K’ order on the impoundment, not on the mine,” she said, although Consol officials did not return an ILN request for confirmation by press time on the status of operations at Robinson Run.
Office of Surface Mining Reclamation and Enforcement regulatory program specialist Dennis Boyles told West Virginia paper the State Journal that divers had been onsite for two days but the slurry that filled the impoundment was too thick for diving.
“It's like jumping into mud," he said.
“You may have 12 feet you'd consider somewhat liquid but you have these fines floating in it so it's not like water. You probably can't see [into] the first two to three feet.
“No visibility. It makes recovery extremely difficult.”
Boyles said Consol was working at the time to build up the embankment around the pond in order to be able to add more slurry.
The pool sits at an elevation of about 1255 feet and the natural ground level in the area of Friday’s accident is 1268ft.
Boyles said the company wanted to build it to 1310ft.
Robinson Run operates a longwall as well as continuous mining sections.
It produced about 5.5 million tons of steam coal in 2011 from the prolific Pittsburgh 8 seam.