A handout community intensity map image made available by the United States Geological Survey (USGS) National Earthquake Information Center showing the area of the 5.3 magnitude earthquake centred on Klerksdorp six kilometres east of Orkney, South Africa. The earthquake was felt in Johannesburg 170 kilometres south west of Orkney.

Johannesburg - The 5.5 magnitude earthquake that struck Orkney in North West yesterday, trapping 3 300 employees underground at two of AngloGold Ashanti’s mines and injuring 21, hardly caused a ripple on the markets.

The earthquake resulted in staff being evacuated at AngloGold Ashanti’s Great Noligwa and Moab Khotsong mines and Village Main Reef’s operations.

The rand was trading at around R10.65 to the dollar when the earthquake struck at about 12.22pm. By 5pm, the local unit was bid at R10.74.

There was a small upward blip in the JSE’s Africa mining index shortly after the earthquake, but it closed 0.01 percent lower at 35 084.91 points.

The Council for Geoscience said the quake measured 5.5 on the Richter scale, with an epicentre near Orkney. It extended to the Stilfontein and Klerksdorp areas and was widely felt.

The earthquake prompted the regulator to ask mining companies operating in the worst affected areas, including Carletonville, Rustenburg and Klerksdorp, to inspect underground conditions to ensure the safety of employees.

“The affected companies must ensure there are no employees still trapped underground,” David Msiza, the chief inspector of mines, said.

AngloGold Ashanti spokesman Chris Nthite confirmed the earthquake had occurred near its Vaal River operations at a depth of about 8km.

Nthite said power had been temporarily interrupted but by mid-afternoon had been mostly restored and engineers had begun clearing shafts.

Stewart Bailey, another Anglogold Ashanti spokesman, confirmed late yesterday that the number of slightly injured miners at the two mines had risen to 21 from the initial 17 injuries reported.

“All the injuries are minor – lacerations and contusions – which are being attended to,” he said.

Of the workers trapped when the shaking struck, 630 were still underground at 6.30pm yesterday. However, it was confirmed that all mining staff had been hoisted to the surface by 7.30pm.

Bailey added that after the earthquake struck, mine management first made telephonic contact with all the crew underground. And then mine engineers inspected the vertical shaft infrastructure to ensure the cage could move freely up and down the shaft.

Only once it was declared safe were workers hoisted back to the surface, he said.

Bailey said it was too early to comment on the extent of the damage in the mines because the engineers had only done a preliminary inspection.

A fuller inspection of the underground damage would only be conducted once all the workers had been brought to the surface and accounted for.

Bailey said it was also too early to comment on when the mines would be able to resume normal production.

Nthite said AngloGold Ashanti’s West Wits operations were unaffected.

Village Main Reef chief executive Ferdi Dippenaar said the group took the necessary precautionary measures, including evacuating employees from underground at its Tau Lekoa and Buffelsfontein gold mines despite not receiving any reports of immediate or serious damage or injuries.

Dippenaar said inspections were expected level by level “to determine if there is any damage and to ascertain that the workings are safe before production resumes”.

Eskom’s media desk reported that it did not have any problems with electricity generation but there were some transmission problems following the earthquake.