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The CSIR continues to contribute to the safety of the country's miners. This year alone, the organisation has shared its knowledge on undergound explosions and the prevention thereof with more than 5 300 miners.
In October, 60 workers from Sasol attended a one-day training course at the CSIR's explosion test facility at Kloppersbos, 40 km north of Pretoria. There workers learnt about possible sources of ignition, which can vary from stone-on-stone friction to smoking or overloaded electrical circuits. They were also reminded about the 'fire triangle' i.e. fuel, heat and oxygen, and viewed a practical demonstration of the danger associated with methane gas.
"South African coal mines have claimed too many lives in underground explosions and fires in the past 30 years. These incidents are caused by flammable natural gases and combustible coal dust in the air," says technical specialist, Isaac Mthombeni of CSIR Knowledge Services. He explains that a hot spark generated during mining operations can ignite these natural gases and coal dust particles. The resultant explosion and fires can often trap workers underground by blocking escape routes.
The mine explosion and fire awareness seminars were specifically developed by the CSIR for coal and hard rock miners to highlight the grave risks associated with methane and coal dust explosions. After participating in the seminars, miners recognise these dangers and strive to reduce the risk of methane and methane/coal dust explosions underground.
"This facility was originally established to conduct research on the mitigation and prevention of methane and coal dust explosions in underground mines," notes Mthombeni, adding that explosions and fires in the belly of the earth were common in the 1980s. This CSIR facility is the only one of its kind in the southern hemisphere and one of only a few worldwide.
"At that time, there was a need for a research facility to be established in South Africa to provide answers to questions, such as whether coal dust adds to the propagation of explosions, should methane gas be ignited underground," he says. Since the establishment of the facility at Kloppersbos, the fatal explosion accident rate has dropped significantly.
"The mining industry has made use of our facility since its inception in 1987," he says, "And mining companies continue to see value in the awareness training seminars offered at Kloppersbos. Among these are familiar names such as Anglo Coal, Gold Fields, Exxaro, Ingwe and BHP Billiton."
Furthermore, the CSIR's Kloppersbos explosion facility has attracted the attention of the international mining community, while students from local tertiary education institutions also make use of the facility for their studies. Mthombeni says the benefits of awareness training have also extended to hard rock mines. "Since hard rock mines have started using the facility, the incidence of fatalities as a result of methane explosions has declined. Although underground explosions may happen naturally, some result from human error. These are preventable if all employees are trained and made sufficiently aware of the hazards. Weak ventilation systems are a common cause of methane explosions. The danger presented by a methane accumulation is often compounded by failure of the methane sensors on cutting machines," continues Mthombeni.
He says the last big explosion in a coal mine was in 1993, when 53 mine workers were killed at Middlebult in Secunda. "The investigation indicated that methane accumulated and was then ignited by a spark, which could have resulted from frictional heat."
The Kloppersbos facility boasts a world-class 200 m long test tunnel and a 40 l explosion vessel that demonstrate the violence of methane and methane/coal dust explosions dramatically. This visual demonstration leaves course participants with a lasting reminder of the risk associated with these hazards. They take with them the lessons learnt and apply these on a daily basis in their work environment.
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