Four deaths confirmed in mining accident

Later on Sunday morning, JSW confirmed the death of a second miner. Zbigniew Meissner/PAP

Doctors have confirmed the deaths of two more miners whose bodies were found after a tremor shook the Zofiówka coal mine, in southern Poland, in the early hours on Saturday, the owner of the coal mine said on Sunday.

The confirmation of the two deaths brings the death toll, so far, to four miners, while a further six remain missing.

The tremor, accompanied by a methane discharge, hit the mine at 3:40 a.m., some 900 metres underground, forcing dozens of workers to flee the mine.

Representatives of the JSW mining conglomerate, which owns the mine, said that rescuers were still looking for the six miners who are unaccounted for.

"The conditions in the endangered area are difficult," the officials said. "High methane concentrations and high temperatures are slowing down the rescue operation."

They also said that 52 workers were in the area when the tremor hit and that 42 of them were able to leave the shaft on their own without injury.

On Wednesday, four miners and one rescuer were killed after two methane explosions hit the nearby Pniówek coal mine, which is also owned by JSW. Attempts to rescue seven miners trapped below ground were suspended on Friday due to new methane explosions at the mine.