Ukraine observed a day of mourning Thursday to pay respects to the 32 miners who died one day earlier in a gas explosion at Zasyadko mine in rebel-held Donetsk. A moment of silence was held at noon across the country, while the Ukrainian flag was flown at half-mast and all entertainment and leisure events were canceled, according to Ukrinform news agency.

As the country mourns, rescue workers continue to recover some of those bodies from inside the mine. The Zasyadko mine is notoriously dangerous and has seen dozens of accidents in its 57-year history. Its name has become synonymous with disaster, Peter Roudik, a Ukrainian-American scholar, said. Over 300 people have died at the mine in accidents since 1999.

Wednesday's explosion was reportedly caused by a gas leak. A potentially deadly mixture of gas can be built up in a coal mine following a gas explosion, which can hamper rescue and recovery efforts. Ukrainian government authorities in the region opened an investigation into the incident, but with the region under rebel control, a proper investigation is nearly impossible, according to Agence France-Presse. Rebel authorities launched an investigation themselves, representatives said Thursday.

Ukrainian officials, including President Petro Poroshenko and Prime Minister Arseny Yatsenyuk, criticized rebels for not allowing government agencies to run the rescue effort. Russia also reportedly offered assistance but the separatists refused.

Eastern Ukraine is rich in resource deposits and has a strong history of mining and heavy industry that was promoted by the Soviet government in the 20th century as exemplary of communist ideals. That identity is still so strong in Donetsk and the wider Donbas region that Russian President Vladimir Putin used it to mock the U.S. and Kiev on Feb. 17. “It is never easy to lose of course … especially when you lose to people who were yesterday working down in the mines or driving tractors,” Putin said.

Sporadic fighting and shelling continues less than 100 miles away from the Zasyadko mine between Ukrainian government forces and pro-Russian rebels, allegedly directly backed by Russian troops and armor. A ceasefire deal signed on Feb. 12 in Minsk, Belarus, between the warring sides called for a drawback of heavy weaponry, but fighting continued in the weeks following its implementation as rebels sought to recapture territory they claim is lawfully under their jurisdiction.