Beijing , China ( CNN ) -- Chinese officials blamed poor management and inadequate precautions for an explosion at a mine that killed 104 people , state-run media said Monday . In addition to those killed , 60 miners remained hospitalized from Saturday 's morning blast at the Xinxing coal mine in northeastern Heilongjiang province . Most were being treated for injuries such as carbon monoxide poisoning and burns , CCTV reported . Six were in critical condition with severe burns . Four other workers were still trapped underground in the mine shaft , the Xinhua news agency said . The accident started with a gas leak in one of the shafts , officials said . But because of poor ventilation , gas poured into the main tunnel and triggered an explosion that shook 28 of the 30 mining platforms in operation . About 530 miners were working in the mine at the time . Luo Lin , head of the State Administration of Work Safety , told Xinhua that the mine 's management was to blame for not evacuating workers when they detected a high gas density in the pit . State regulations stipulate that miners have to evacuate if gas density exceeds 2 percent . The density in the pit was more than 10 percent , authorities said . `` The mine has too many mining platforms in operation and has sent to many workers down the pit to increase output , '' said Zhao Tiechui , deputy head of the work safety agency . The mine is owned and operated by the Heilongjiang Longmei Mining Holding Group . Unlike most small- and mid-size collieries , Xinxing produces 12 million tons of coal a year . The blast took place during a five-day inspection of work safety conditions in Hegang , local media said . Immediately after the blast , the mine 's director , deputy director and chief engineer were fired . Mine accidents are common in China . Last year , 3,200 people were killed in such accidents , state media said . The latest blast is the deadliest since December 2007 , when 105 miners were killed in Shanxi province . The deadliest mine blast took place in August 2007 when two collieries flooded in Shandong province , killing 181 miners , Xinhua said . Chinese officials said they will pay at least 250,000 yuan ( $ 36,600 ) to each of the families of the miners who died .
Chinese officials blamed poor ventilation and inadequate ventilation for an explosion . It killed 104 and injured 100 others . Last year , 3,200 people were killed in mine accidents , state media said . Four miners still trapped underground , state media reported .