Workers at the Mt Arthur coalmine have told the Newcastle Herald that more potentially water-damaged shots are buried in the ground, shots with the same capacity to create toxic smoke and fumes as was seen above the Muswellbrook industrial estate last month.
The shots have been underground for longer than recommended, and may be water damaged, the same conditions that led to the botched blasting episode of February 18.
Mining workers have said that the mine management could solve the problem by using a better, more expensive explosive product that is less susceptible to water contamination.
A statement issued by a BHP Billiton spokeswoman said Mt Arthur Coal ‘‘does not use contaminated blasting material on site’’.
It also said the mine was taking additional measures and precautions to prevent ‘‘a fume incident’’, such as ‘‘using an explosive that is less susceptible to contamination via water’’.
‘‘The ongoing use of this explosive will be evaluated based on the outcomes of the investigation,’’ the statement said. ‘‘Mt Arthur Coal takes it’s environmental and community obligations seriously, and continues to work with the EPA and other local government agencies.’’
A spokeswoman for the EPA, which is investigating the blast, including the length of time it was left in the ground, said its inquiries were continuing.
‘‘We need to get all the evidence, listen to what the company is telling us, conduct interviews with people from the community, and we will be making no comment until that is completed,’’ she said.
The blast on February 18 led to public health warnings and an apology from BHP Billiton after a smoke plume containing poisonous nitrogen dioxide gas spread several kilometres from the site, turning the sky to turn bright orange, and leaving several people with irritable, sore throats.