HEFEI - The search for 21 miners trapped in a collapsed mine in east China's Anhui Province was concluded and all the missing were confirmed dead, authorities said.

An explosion ripped through the Dongfang coal mine in Huainan City on Aug. 19 and 39 workers were caught in mine shafts hundreds of meters underground. Twelve managed to escape. By Aug 29, six bodies had been found and 21 remained missing.

According to officials with the Huainan city government on Tuesday, the search was hampered by collapsed mine shafts and gas pockets. Experts said more explosions were possible if the search continued while they also concluded that the trapped miners were dead due to the conditions underground.

The families of the 21 missing miners received 910,000 yuan ($14,841) compensation for each miner.

The provincial coal mine safety inspection bureau revoked the privately-owned Dongfang coal mine's production permit in August. The mine has an annual production capacity of 90,000 tonnes.

At the time of the incident the mine was operating illegally. Although officially licensed, the city government had issued production suspension orders for all coal mines beginning June 30 as part of flood prevention efforts.