The allegation is that a spillage from a pipe at the mine's operations in Stilfontein, near Kerksdorp, last week led to uranium-laden water going into a local river.
An incident report, filed to the National Nuclear Regulator by the company, said the spillage had occurred due to a "pipeline failure" between two of the company's plants. Every spillage like this requires a report to be filed to this body, and to the department of environment affairs.
It occurred last Tuesday after bolts in the pipe were stolen in a section of pipe next to the Koekemoerspruit, the report said. This led to one hectare being covered in polluted water, along a 1.6km stretch of land.