How safe are construction site blasts? Is the blasting around Grahamstown safe? 'At no time during the operations was there any reason for concern' – expert.
How safe are construction site blasts? Is the blasting around Grahamstown safe? 'At no time during the operations was there any reason for concern' – expert.
The Grahamstown Explosives Unit of the South African Police Service has urged residents to follow safety instructions whenever there is a planned blast.
An expert spoke to Grocott's Mail in response to a 12 September report on the Extension 6 blast which residents said damaged homes and property ('Blasts wreak havoc').
Blasting was done in the area to break up rock so sewage lines could be laid. Acting head of the unit, Warrant Officer Henk Coetzer, who was at the site of the blast, said residents had responded badly to requests in the interests of their safety.
An extract from Coetzer's emailed statement to Grocott's Mail reads, "When the blasting took place the local Inspector of Explosives was at the blasting site monitoring everything.
"This in itself was really a big issue to keep everyone away whilst trying to have all completed to set the blast off." He said despite signs and guards, some members of the public had become aggressive when they were asked to stay out of the danger area.
"Over and above the fact that a lot of inebriated community members tried to get in everywhere."
Of the blast itself, Coetzer said the degree of vibration caused by the blast was less than that experienced in earth tremors in Johannesburg on a normal day. "It was not likely to cause television screens to crack," he told Grocott's Mail. Coetzer denied that the excavator pictured on the front page of Grocott's Mail's 12 September issue had falllen into the trench as a result of the blasts. He said this had happened before the explosion.
"The excavator which had fallen into the trench during the operational work had crashed inside the trench whilst trying to fill the trench with sand to help safeguard the explosives during blasting," Coetzer said.
"In other words the soil underneath its tracts was saturated from leaks which took place prior and thus made the soil collapse.
"At no time during the operations was there any reason for concern regarding the type of explosives used, as this type of explosive is very stable and safe." Coetzer also corrected reports that dynamite had been used.
"The use of any type of dynamite in South Africa has been phased out in the early to late 1940s. "Dynamite is very dangerous and unstable after a certain period of time," Coetzer explained. Coetzer also said a permit for the blast had been issued by his office and that rigorous inspections are carried out at blasting sites.
This is according to the Explosives Act 26 of 1956 regulating what, when, and how explosives are applied. Coetzer said precautionery measures were taken before last week's blast was set off.
"The blast was split into two parts due to the time constraints," Coetzer said. "All occupants in the adjacent houses were all requested to leave the dwellings as an added extra precaution." He also said all the homes in the area were photographed prior to the blasting to differentiate existing damage from that caused by the contractor.
The blasting took place on Saturday 6 September at approximately 5.20pm, Coetzer said.
