Two separate blasts occurred within three days at the Babao mine operated by state group Tonghua Mining in the northeastern province of Jilin.
Following suspicions from the provincial government that the reported death toll from the first blast was inaccurate the primary Chinese watchdog, The State Council, launched a full investigation into the blasts.
The investigation’s report was released Thursday, state news website Xinhua reported.
The State Council found Tonghua Mining only reported 28 deaths and 13 injuries from the March 31 blast but the real death toll amounted to 36, including one injured worker who died after medical treatment failed on March 31, the report said.
The State Administration of Work Safety has separate penalties for accidents that cause fewer or greater than 30 deaths.
When the second gas explosion occurred on April 1 a total of 17 people died and eight were injured in the accident. The company had ignored a closure order from officials and sent the workers down the mine illegally.
Further investigation showed Babao Coal Mine also concealed deaths of six workers in five accidents in 2012, the report said.
It said three gas explosions, which did not cause casualties, occurred in the mine in 2013 prior to the fatal accident in March and were not reported.
