Rescue workers reached 19 workers trapped in Polish copper mine and were bringing them to the surface, a spokesman for the mining company told Reuters Wednesday.

The miners were trapped underground after an earthquake caused a cave-in late Tuesday night, Reuters reported.

Dariusz Wyborski, a spokesman for mine operator KGHM, told reporters that all the workers were alive.

Earlier reports initially mentioned 17 workers, then 18 trapped.

Reuters reported that the miners were  trapped about 600 yards below ground at the Rudna mine, about 249 miles southwest of the Polish capital, and workers on the surface lost contact with them for several hours.

"There was a quake in the Rudna mine," Wyborski said earlier, according to Reuters. "The rescue operation is difficult because huge amounts of rocks have to be removed."

Four injured miners were able to come out of the mine on their own, according to newspaper Gazeta Wyborcza.

The mine, which has been in operation since 1974, is in the Silesia region, near Poland's borders with Germany and the Czech Republic. The operator, KGHM, is Europe's second-biggest copper producer.

Poland has large numbers of mines, mostly in the heavily industrialized Silesia region. In 2006, a gas explosion at a coal mine in the region killed 23 miners.

Reuters contributed to this report.