Part of Oxford Road in Johannesburg collapsed on Tuesday during drilling operations for the Gautrain rail project.
A Gautrain safety representative said he had ”no idea” what caused the collapse, which happened during routine drilling at about 1.30pm.
”It was a shock,” the representative said.
The collapse created a hole about 12m wide in the road between Eighth and North avenues.
It appeared a water mains was hit during the drilling because water was gushing out of the hole, into which part of a wall and a street light had fallen. Because of the water it was impossible to see how deep the hole was.
Safety officials were trying to determine if there were any other cracks along the road that could pose a danger for vehicles.
The area was cordoned off and motorists were being diverted off Oxford Road into Riviera Road and 11th Avenue. No injuries were reported.
Dozens of Gautrain workers, metro police and paramedics were on site.
Metro police Chief Superintendent Wayne Minnaar said the affected section of the road was likely to be closed for the next two weeks. ”It is a safety hazard. The road can fall in even more.”
He said workers had noticed cracks while drilling along Oxford Road. They then closed the road. Shortly after the closure, the section of the road caved in.
Andre Mugabe, who works at a business on Oxford Road, told the Mail & Guardian Online: ”I heard a big banging sound while I was washing the cars, it was like an earthquake, and then a couple of minutes later water started coming out of that hole.”