Search intensifies for missing Pennsylvania grandmother as crews encounter unstable mine shafts

The search for the grandmother believed to have fallen into a massive sinkhole continued on Wednesday, as Pennsylvania authorities encountered unstable portions of the abandoned mine below the sinkhole.

Elizabeth Pollard, 64, was searching for her lost cat Pepper when she disappeared in Marguerite, Pennsylvania, on Dec. 2. She parked near a local restaurant with her five-year-old granddaughter in the car at the time.

Marguerite, a sparsely-populated village, is vulnerable to sinkholes due to past mining activity. Authorities believe that Pollard fell into the former Marguerite Mine, which was last operated in 1952.

Crews determined that parts of the abandoned coal mine were too unstable to safely search for Pollard but still expressed hope that the 64-year-old grandmother would be found alive.

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On Wednesday, Pleasant Unity Fire Chief John Bacha said that crews made it to the spot where Pollard is believed to have fallen, but found no sign of her. 

Bacha, the operations officer of the mission, said that mud may have moved her somewhere else in the mine.

"We did get, you know, where we wanted, where we thought that she was at. We’ve been to that spot," Bacha explained. "What happened at that point, I don’t know, maybe the slurry of mud pushed her one direction. There were several different seams of that mine, shafts that all came together where this happened at."

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Authorities are hoping that Pollard is still alive, though conditions have been mixed. Although nightly temperatures had lowered to freezing early this week, officials have said that parts of the sinkhole still have adequate levels of oxygen.

"All oxygen levels have been perfect," Bacha told KDKA on Tuesday. "No carbon monoxide, no explosive gases, no anything."

"The atmosphere has been perfect at this point, so we still have some hope that there's a void and we'll be able to get there."

Authorities are actively investigating the incident. No additional details are known at this time.

The Associated Press contributed to this report.