The company announced on Sunday it had suspended the world's deepest gold mine after testing confirmed 164 cases.
In an update yesterday, AngloGold Ashanti said 196 positive cases had been identified now 651 tests were complete.
It said the "vast majority" were asymptomatic and all were being isolated in line with national health protocols.
The company said the testing took place after a positive COVID-19 case was detected last week at Mponeng, which employed about 5,000 people in 2019.
The mine had been operating at 50% capacity under South Africa's restrictions designed to limit the spread of the pandemic.
AngloGold Ashanti said the mine remained voluntarily suspended to enable contact tracing, further engagement with relevant stakeholders, plus deep cleaning and sanitisation.
"The management of the mine and its medical team are working closely with the regional health authorities in our joint efforts to slow the rate of infection and to protect those who may be most vulnerable," it said.
Its shares closed 4.3% lower to 43,796c but remain near the upper end of a one-year range, capitalising it at ZAR182.2 billion (US$10.4 billion).
The company is selling its South Africa assets, including Mponeng, to Harmony Gold Mining under a US$300 million deal expected to close this year.
The number of COVID-19 cases in the mining industry rose to 263 yesterday, according to the Minerals Council South Africa, compared with 22,583 in the country and more than 5.5 million globally.
Impala Platinum suspended its Marula operation after detecting 19 cases 10 days ago and Harmony Gold last week reported two cases at its Kalgold operations, which it said would only return to full production once safe to do so.