A coal company and local county government in North China's Shanxi province were suspected of concealing a coal mine fire which left one dead and six others injured recently, provincial mine safety authority said Friday.

The accident happened at 11 am Monday at a coal mine of Kunlong Coal Industry Corporation in Zhongyang county, according to Shanxi Administration of Coal Mine Safety.

Workers triggered the fire when they used oxygen welding against safety regulations while clearing the shaft, the administration said in a statement.

Six workers were injured, and one of them died in hospital. The other five are still receiving treatment in hospital.

According to the statement, the company reported the accident to the county government at 5 pm Monday, six hours after its occurrence, but the provincial administration did not receive the report until 1 a.m. Friday.

The case was not revealed until Xinhua reporters sought confirmation from the bureau when learning of the case from local residents.

A team has been sent to the county on Friday to investigate.

Based on rules and regulations issued by China's State Administration of Work Safety, in case of any coal mine accident, the involved company should report within one hour to local safety supervisory departments of county-level government or above, which then should report to the provincial safety supervisory administration within two hours.