Twenty-eight female guards were unfairly dismissed by a security company because the client‚ Metrora.
The bones of 16 people have been discovered in unmarked graves between New Canada and Main Reef roads in Robertsville, Johannesburg.
Archaeologists who were summoned to the site said they expected to exhume about 50 human skeletons within the next six weeks.
They think the bodies were buried 50 to 100 years ago.
The discovery was made in December last year when property developers began to dig trenches in the area for the construction of houses.
"The company immediately stopped digging after finding human remains and consulted the South African Heritage Resources Agency, who then tasked us with the scientific investigation of the skeletons," said archaeologist Anton Pelser.
The digging of the graves began last week Monday and about 16 skeletons had been discovered by Friday.
Avbob undertakers will exhume the bones.
Pelser said preliminary investigations showed that the people were buried between 1897 and 1940.
"We are yet to establish to whom they belonged, but we can confirm that one of the skeletons is that of a Chinese man."
All the 16 skeletons found so far were men between the ages of 20 and 30. They are believed to have been migrant workers on the mines in the area.
"Old maps show that the area was used as a burial site in the 1900s. But it became an official cemetery only in the 1940s.
"People forgot about the cemetery's existence."
Pelser said some skeletons were interred on their sides facing north, but others were laid on their backs.
"We still have to establish what the cause of their deaths were and who these people were," said Pelser.