Islamabad, Dec 4 : At least six coal miners were killed after getting trapped due to a gas explosion inside a coal mine in Harnai district of Pakistan's southwestern Balochistan province, officials told media. According to the reports, six miners were working inside the Shahrag coal mine of the district on Saturday when an explosion occurred in the mine which led to the collapse of a portion of it. The officials said that fire erupted after the gas explosion some 1,500 feet deep inside the mine which blocked the entrance. Resultantly the miners got trapped in the mine, Xinhua news agency reported. The workers in the area and the rescue teams immediately rushed to the site and started a rescue operation, local media said, adding that following a seven-hour operation the dead bodies were retrieved. /IANS