A total of 906 government officials in North China's Shanxi province were punished in the past 11 months during a provincial campaign against corruption in the coal mining sector.

The officials, including a former vice-mayor and the former public security head of Datong city, were found to have received bribes or committed other crimes related to the coal mining sector, the provincial government's supervision department disclosed at a press conference on Wednesday.

During the campaign, launched in July 2008, 2,353 people so far have been punished in 2,185 cases, said Xing Shunxi, deputy director of the supervision department of Shanxi government.

An amount of 30.4 billion yuan ($4.6 billion) of illegal funds has been retrieved, a figure equal to one-third of the provincial government's revenue in 2009.

In the 11 months to November, the province received 759 reports of corruption and seven department-level government officials were sacked.

Shanxi, known for its coal industry, possesses 260 billion tons of known coal deposits, about one-third of the country's coal resources.

However, Shanxi's coal mines have been plagued by flooding, blasts and other accidents, and thousands of miners are killed every year in China due to reasons including lax regulation, corruption and inefficiency.

According to Xing, the anti-corruption campaign focuses on detecting officials who have invested in the coal industry, a practice that is banned in China, on officials taking bribes and on those who illegally resell State assets during property reconstruction.

One of the most prominent cases involved Wang Yanfeng, former vice-mayor of Datong, who is accused of "accepting a large amount of money as a bribe in coal mine assets' transfers".

Hao Pengjun, former director of the coal industry bureau of Puxian county, was found to have acquired 305 million yuan ($45.8 million) by abusing his power and illegally running a coal mine business. He was sentenced to 20 years' imprisonment in April.

According to official figures, in the past 60 years Shanxi has produced 12 billion tons of coal, of which 75 percent had been transported to other regions.

However, its coal-based economy had not brought prosperity to the people of Shanxi, where urban per capita disposable income and rural net income ranked lower than 20th among the mainland's 31 provinces, municipalities and autonomous regions.