Johannesburg - A coal storage silo that collapsed at Majuba power station in Mpumalanga had been showing signs of stress since January, trade union Solidarity said on Tuesday.
“It came to our attention that Eskom was well aware of the silo problems since January,” Solidarity head of industry Deon Reyneke told Sapa by phone.
The collapse at the weekend caused Eskom to warn of rolling blackouts countrywide, with the parastatal saying a crack in a coal storage silo on Saturday afternoon caused the loss of 1800MW of Majuba's total capacity.
At the time spokesman Andrew Etzinger said the silo ruptured or cracked and employees were evacuated. He said it “just collapsed”.
But Reyneke said Solidarity members employed by Eskom said the power utility started monitoring resonance in vibrations at the silo earlier this year.
“The monitoring equipment picked up that vibrations that used to happen every 30 seconds in June and July, was happening every three to five seconds three weeks ago,” he said.
“Eskom did nothing to correct the problem... According to information I have no preventative maintenance was put in place.”
He said the resonance in vibrations meant that the silo was under stress and cracks could be seen.
On Tuesday, Etzinger said the silo was inspected last year.
“When the silo was inspected last year it was found to be structurally sound,” he said.
“As Eskom we want to ask Solidarity to give us the relevant information they have that could assist with our investigation.”
Before the collapse Majuba supplied 3600MW, roughly 10 percent of the country's electricity capacity, Etzinger said on Sunday.
“The conveyer belt systems, which feeds coal to the power station, were damaged and therefore we can't get coal into the power station,” he said on Sunday.
Eskom would bring mobile coal conveyer belts from other stations to Majuba as a temporary solution, but this would take time, said Etzinger.
Eskom said on Sunday the collapse could cause rolling blackouts across the country but on Monday scheduled power cuts were put on hold.
The silo, which stores over 10 000 tons of coal, cracked on Saturday afternoon, affecting coal supplies to all six units at the power station.
Johannesburg, Ekurhuleni and Cape Town residents were warned of power cuts. - Sapa