The search for a grandmother who apparently fell into a sinkhole while looking for her cat earlier this week in a coal mine town about 40 miles southeast of Pittsburgh is now a recovery mission, state officials announced.

The hunt for Elizabeth Pollard entered day three Thursday with crews, who officials have performed what state troopers called an impressive, grueling effort on the ground, attempting to locate the 64-year-old woman.

“It’s now a matter of trying to find her and do right by her family,” Pennsylvania State Police spokesperson Trooper Steve Limani said during a news conference Wednesday night, adding there have been no signs of life since she vanished Monday.

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Crews search for missing grandma at abandoned mine

Limani said crews had worked “a full two days” pumping water through a long-abandoned underground mine at the site suctioning out dirt, debris and rocks to clear an area and search for Pollard – a process Limani compared to trying to pull a boulder out of a house of stacked cards.

“(Crews) were just busting their butts, covered in mud, everything they could to move debris,” Limani said.

The abandoned mine is in Marguerite, an unincorporated community and coal town in Westmoreland County.

“During the course of our day today we’ve experienced some difficulty when it came to trying to work on the mine and access to the mine and the fragile state the mine is in,” Limani said, adding there is a good chance the mine may collapse.

Limani said troopers met with her family Wednesday night to update them on the search.

Crews had to switch gears due to unstable mine

At the risk of the safety of people who are in there, the compromised condition of the mine, and the potential for inclement incoming weather including snow, Limani said, crews have had to switch gears.

The trooper said crews will now work dawn until dusk to dig out a large plot, “more than four times the size of the area that we had originally done, to try and secure the mine so crews can access it to try and go in there and recover her. It’s going to be at least another day of just solid digging.”

Despite crews pumping oxygen into the mine, Limani said oxygen levels remain lower than what someone would want inside “for someone to try and sustain their life.”

Pleasant Unity Fire Chief John Bacha said in a Wednesday news conference, Bacha said the danger became apparent around 3 a.m. Wednesday, and the roof of the mine had collapsed in several places making it unstable.

Troopers ‘virtually positive’ Elizabeth Pollard fell into sinkhole

Limani said troopers are “virtually positive” Pollard fell into the sinkhole near Monday’s Union Restaurant in Unity Township.

On Wednesday, PSP Communications Director Myles Snyder told USA TODAY a camera lowered into the hole revealed what appears to be a shoe.

Pollard was last seen about 5 p.m. searching for her cat Pepper, troopers said. Pollard’s family contacted state police at around 1 a.m. Tuesday morning to report that she had not come home.

Police found Pollard’s car behind the restaurant around 3 a.m. with her 5-year-old granddaughter safe inside, the agency reported. State troopers found a sinkhole in the area near the car nearly the size of a manhole cover.

“The sinkhole, it appears that it was most likely created during the time, unfortunately, that Mrs. Pollard was walking around,” Limani told KDKA on Tuesday. “We don’t see any evidence of any time where that hole would have been there prior to deciding to walk around and look for her cat.”

USA TODAY has reached out to Limani for more information.

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What is a sinkhole?

According to the U.S. Geological Survey, a sinkhole is a hole in the ground that opens up when there is no external surface drainage. When water builds up, it drains into the subsurface and dissolves the sediment below, creating caverns until the ground surface itself collapses.

They can form from natural or manmade causes, according to Pennsylvania’s Department of Environmental Protection. They also can crop up after extreme weather.

In the U.S., they’re most common in these states: Florida, Texas, Alabama, Missouri, Kentucky, Tennessee and Pennsylvania, according to the American Geosciences Institute.

Pollard’s granddaughter unable to provide details about what happened

Pollard’s granddaughter, who’d been in the car for almost 12 hours in freezing temperatures, was found unharmed, troopers said.

The girl, now safe with her parents, was unable to give law enforcement any details about what happened.

“She was just a 5-year-old girl that was waiting in the car for her grandmother to come back,” Limani said.

Contributing: Jeanine Santucci and James Powel

Natalie Neysa Alund is a senior reporter for USA TODAY. Reach her at nalund@usatoday.com and follow her on X @nataliealund.