(AP) — Crews desperately continued removing massive amounts of water in an effort to locate a trapped worker inside a flooded coal mine in West Virginia as the work entered a fifth day Wednesday.

Gov. Patrick Morrisey said the efforts by crews about three-fourths of a mile into the Rolling Thunder Mine remained a rescue operation. Machines were pumping out water at a rate of 6,000 gallons (22,712 liters) per minute, he said. That’s enough to fill an Olympic-sized swimming pool in under two hours.

“I think people are doing everything imaginable,” Morrisey said. “There’s no quit in anyone here.”

Old mine wall collapsed

A mining crew hit an unknown pocket of water Saturday about three-quarters of a mile into the mine near Belva, about 50 miles (80 kilometers) east of the state capital of Charleston. The mine flooded after an old mine wall “was compromised,” and multiple state agencies were involved in the response, Morrisey said.

Other miners were accounted for after the accident was reported. Morrisey said he had no estimate on the number of crews working on the rescue effort inside the mine, but “obviously there are a lot of machines pulling the water out.”

“There’s a lot of water that’s been drained, but there’s also a massive amount in there that still needs to be drained,” he said, estimating that the water level was dropping about one inch (2.5 centimeters) per hour.

In addition, holes have been drilled in the mine and dive teams have explored potential areas in the water where air pockets might exist, the governor said. The National Cave Rescue Commission has provided surplus Army phones attached to wires that can travel great distances to enable for better underground communication.

The United Mine Workers union also sent its safety experts to the nonunion mine.

“We are all coal miners, and we all care about the safety and health of each other,” union President Brian Sanson said in a statement.

Area ‘extensively explored’

Rolling Thunder is one of 11 underground mines operated in West Virginia by Tennessee-based Alpha Metallurgical Resources Inc. The company also operates four surface mines in the state, as well as three underground and one surface mine in Virginia.