The dozer is believed to be stuck 25 to 35 feet in the slurry, the refuse and solid material that sit beneath about 10 to 12 feet of dirty water. Slurry is the waste created when coal is washed to help it burn more cleanly.
Crews will pump the slurry out from around the dozer, Louviere said, and replace it with water so divers can enter and search for the missing operator. It's unclear how the bulldozer will be removed. Pittsburgh-based CONSOL has scheduled a technical briefing for the news media for Wednesday afternoon, but said the telephone event would last only 15 minutes and not include an opportunity for reporters to ask questions.
Louviere said there was no risk to the public from the failure of the 200- by 200-foot section of the embankment because the structural problems were inside, not outside, the impoundment.
The pond encompasses about 78 acres and is estimated to hold between 1.6 billion and 1.9 billion gallons of wastewater, said state Department of Environmental Protection spokeswoman Kathy Cosco.
That's the equivalent of about 2,500 to 2,900 Olympic-size swimming pools, each holding about 600,000 gallons.
The impoundment is permitted to hold 3.4 billion gallons, Cosco said, but typically operates well below that volume.
The mine was idled over the weekend, and production has not yet resumed.
Two engineers whose pickup trucks also went into the slurry suffered no life-threatening injuries.