An explosion in a Chinese coal mine has left at least 30 miners missing only a day after a blast in another mine killed eight workers, local officials have said.

Two people are said to have survived the explosion, which occurred at around 0440 (2040 GMT) on Saturday morning at the Boaxing Coal Mine near Harbin, capital of the northern Heilongjiang province, about 600 miles (1,000 kilometres) northeast of Beijing, China's official news agency Xinhua said.

Rescue workers are currently searching for those missing, however one official said that the likelihood of finding the miners alive was unclear.

"It's difficult to say whether the... missing miners can be saved," he said.

"The explosion destroyed the shaft, so rescuers have not reached the accident site."

An investigation has been launched into the cause of the blast.

Poor safety record

On Friday another explosion, this time at a coal mine in the neighbouring province of Jilin in the Songshu in mine the city of Baishan about 500 miles (800 kilometres) northeast of Beijing, killed eight miners as they were buried under tons of rock.

An employee told the Associated Press news agency that the blast was caused by natural gas, however officially an investigation is said to be ongoing.

China's mining industry has the world's worst record for work safety, with Beijing's work safety bureau reporting that at least 4,500 fatalities occurred in coal mines last year, although unofficial estimates put the figure as high as 10,000.

Many such incidents occurred in privately owned mines which lack operating licences and adequate safety equipment.

Thousands of such mines have remained open despite a long-running campaign to shut down those that are unlicensed.

China relies heavily on the coal industry for its energy needs.