JOHANNESBURG - Acid mining drainage has been ruled out as the cause of the explosion in the Johannesburg CBD.
A suspected underground gas explosion ripped open roads and damaged cars.
Mining expert Professor Terence McCarthy says a large sewerage pipe might have been involved.
READ: Joburg Explosion | Institutions brought in to determine cause - Lesufi
Three manholes are central to the investigation of the bizarre explosion on Bree Street.
It left one person dead, over 40 injured and dozens of vehicles damaged.
Gauteng Premier Panyaza Lesufi says the Labour Department has identified certain institutions to speak to.