The size of the explosion at a mine in the Ningxia Hui autonomous region last week, which left 16 people dead, might have been exaggerated by tons of discarded dynamite left in the mountainside almost a year ago by the same blasting firm, an explosives expert has said.

Although engineers with the Guangdong Hongda Blasting Co Ltd, which handled the explosion, claimed to have used just 3 tons of dynamite, the blast triggered a 2.4 magnitude earthquake and rained stones on communities as far as 1 km away - four times the distance engineers had estimated.

Sixteen miners were killed in the incident and 53 other people were injured, 12 of them seriously.

Liu Zhanwu, an explosives expert from Ningxia, told the Guangzhou-based Nanfang Daily last week that such a massive blast could not have been caused by just 3 tons of dynamite.

"At least 100 tons of explosives would be needed to produce that kind of damage," he was quoted as saying.

Guangdong Hongda Blasting Co Ltd had been employed to blast the top off the same mountain in December - using 5,500 tons of dynamite.

However, Zheng Bingxu, the company's general manager and senior blast engineer, told China Central Television last week, that he had no idea there were any live explosives in the area.

The firm did not even take the underground situation into consideration when drawing up the blast plan, he admitted.

Under the national safety law, the company should have checked both before and after the blast for any live explosives.

According to a notice posted yesterday on the website of the State Administration of Work Safety, eight employees from the blasting firm, including the project manager, are now helping police with their enquiries.

The incident had exposed "several problems" the notice said.

The first is that both Guangdong Hongda Blasting and the Dafeng Mine (where the explosion took place) had failed to follow good management practice with regard to the handling of explosives and detonators, it said.

Some 4,500 detonators were taken to the blast site, the notice said, and although only several hundred were used, the rest were not returned.

Also, some of the blasting techniques used on the project were found to be "problematic", it said.

The Nanfang Daily also quoted an unnamed expert as saying the incident reflected the lack of an effective inspection process for blast projects in the region.

Both dynamite and detonators are regularly handled by unqualified personnel, he said.

(China Daily October 20, 2008)