WARSAW (Reuters) - The final death toll of an earth tremor causing rockfalls deep underground in Europe’s largest copper mine in southwestern Poland rose to eight miners, the mine’s operator KGHM said on Wednesday.

The tremor hit the Rudna copper mine at 2009 GMT (3.09 p.m. ET) on Tuesday, KGHM said, causing extensive damage, but the mine remained mostly open.

Earlier on Wednesday KGHM officials said the tremor had killed five miners and that rescuers had been looking for three other trapped elsewhere in the mine. In their latest statement, the officials said the three miners had been .

“The rescuers have found the three miners’ bodies next to each other. Thus, the outcome of this tragic tremor is eight casualties,” state-run news agency PAP quoted the Rudna mine director Pawel Markowski as saying.

“The rescue operation lasted for 24 hours. We have done everything to save the miners, unfortunately we lost”, Markowski added, calling the tremor KGHM’s biggest tragedy in the past 55 years.

The epicenter of the tremor was 1,500 meters below the surface, with a magnitude of 3.4, PAP reported.

Sections of tunnels hundreds of meters below the surface were blocked by rocks, preventing access to the missing miners.

Slideshow ( 9 images )

Markowski had said earlier that it was the first time in KGHM’s history that such a distant tremor had caused such extensive damage.

State-run KGHM said the Rudna mine, in operation since 1974, had 11 shafts reaching a depth of 1,244 meters.

“We are all shocked by the scale of this tragedy, which occurred in a place we had assessed as exposed to a moderate level of risk,” KGHM Chief Executive Officer Radoslaw Domagalski-Labedzki told reporters earlier on Wednesday.

PM VISITS SITE

Domagalski-Labedzki also said nine people working in the mine had suffered spinal and head injuries and five were in hospital. KGHM’s spokeswoman said none were in a life-threatening condition.

“We all have high hopes that the news will be positive. This does not change the fact that the rescue operation is taking place in difficult conditions,” he said before rescuers had confirmed the eighth death.

Slideshow ( 9 images )

Officials at KGHM said some of the underground tunnels still blocked by debris were eight meters wide and four meters high.

Tremors often occur in underground mines as removing ore and digging tunnels from beneath the surface weakens the structure of the surrounding rocks. But most tremors are harmless.

Prime Minister Beata Szydlo canceled the government’s weekly cabinet meeting and visited the mine late in the afternoon.

“We are ready to help whenever such a need arises. We hope that those who have not been found yet will come back alive,” Szydlo said before the final deathtoll was known.

Shares in KGHM were up 0.55 percent on Wednesday. The company said it was too early to assess the damage and costs caused by the accident.

“After the rescuing operation is finished, a special commission with the representatives of the State Mining Authority and KGHM experts will be convened. Only the part of the mine where the accident took place will be halted,” a KGHM spokeswoman said.

KGHM is one of the biggest copper and silver producer in the world. Its copper output stood at almost 700,000 tons in 2015.