Dereliction of duty and abuse of authority are believed to be the main causes behind a series of coal mine blasts that have caused huge casualties in China, a report of the Supreme People's Procuratorate (SPP) said Tuesday.

After investigations into nine major blasts in 2005, each with a death toll of more than 30, the SPP found six involved official malfeasance and held 46 government officials responsible, according to the report.

It attributed the main cause of these accidents to violation of safety rules in which coal mine owners ordered excessive operation regardless of production limits.

"Such illegal operations are closely linked with criminal negligence of government officials in carrying out supervision duties," said a spokesman with the SPP's anti-malfeasance bureau.

"In many cases, malfeasance is the result of corruption, which in turn, aids and abets such official negligence," the official said.

The report also detailed specific cases. Hu Jianchang, former deputy director of the Guangdong Provincial Administration for Work Safety, was charged in June, 2006 with neglect of duty and accepting the equivalent of over 530,000 yuan (about 70,000 U.S. dollars) in bribes from coal mine owners following a coal mine flooding that left 121 people dead.

In another case at the Jiajiabao Coal Mine in Ningwu county of Shanxi Province in July, 2005, two senior party officials in Ningwu county collaborated with mine owners to hide the bodies of 17 dead miners after a gas explosion in order to escape punishment.

The report also found that some of the officials had invested in the coal mines they supervised or ensured certain mines were operated by their relatives or friends.

Figures from the State Administration of Work Safety, China's safety watchdog, show that coal mine accidents killed 4,746 people in China in 2006.