Methane caused Joburg explosion, repair estimate is R178m

The gas which caused a blast on Lilian Ngoyi (formerly Bree) Street in Johannesburg's CBD about two weeks ago was methane.

Johannesburg city manager Floyd Brink said on Wednesday methane is lighter than air and it travelled up along the services tunnel, from an unknown source to the crest of a tunnel near Von Brandis Street. 

Brink addressed journalists along with mayor Kabelo Gwamanda and consultant and civil engineer Johan La Grange on Wednesday. 

He said the estimated cost for repairs was R178m but that might change once the municipality receives the detailed designs for the entire project. “This will include the redesign of that particular road. It's an estimate, we are not at a detailed design stage.

“Once we clear the rubble, we'll see what is damaged from the side of Joburg Water, whether it’s the water system, stormwater drains or even the sewer systems. We will have to do something with regard to some of the cables underneath for City Power and how to block them off,” he said.

Brink said the city had met the property owners in the area “and we have already agreed on an approach in which they will be part of our planning”.

He said repairs would be done in a short time.

“We can guarantee you it won't be 18 months, our procurement processes in the city are a bit shorter because we do have pre-qualified bidders on our panels in the different entities.”

He added that in the interest of transparency, the city has so far spent around R4m on professional experts’ services, cordoning off the site and the provision of water tankers and temporary ablution facilities. 

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