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A gas explosion at a coal mine in western China killed 21 mine workers on Friday, Dec. 13, the Associated Press reported.

Initially, reports from the site stated that the miners were trapped as a result of the blast in the mine, located in Xinjiang region's Changji prefecture. However, several hours later an official at the local work safety bureau announced that 21 miners has been confirmed dead and one was injured in the incident. There were 12 other mine workers close to the explosion site but they managed to escape without injuries, the news source said.

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According to the State Administration of Coal Mine Safety, quoted by the official Xinhua News Agency, the mine was ordered to cease production in June because of numerous safety practice violations recorded there. The mine operator was supposed to improve safety conditions in the mine before being allowed to resume operations.

Incidents like this one typically occur when shafts have not been properly ventilated to help methane gas escape. Explosions, cave-ins and floods are not a rare occurrence in China's mines, which have the highest death rates in the world. Although in recent years a variety of safety improvements have been introduced and the number of deaths has dropped, regulations and standards in China are still often ignored, the Associated Press noted.