The men - two South Africans and three Zimbabweans - were found in possession of gold valued at more than R120000, four vehicles and R75000 in cash during a police operation last month.
During the arrest police also found 11 bottles of schedule four medicines, syringes, needles and sterilised water. The medicines were apparently used by the illegal miners underground, Welkom police spokesman Captain Stephen Thakeng said.
The syndicates recruit men from neighbouring countries and sneak them into mines with the help of corrupt mine security officials and staff members.
"The Hawks in Welkom launched an operation called Project Mercury, which took them five months of intensive investigation, to organise with the directorate of public prosecution to authorise the transaction and arrest of the suspected gold buyers," said Thakeng, who added the aim of the project was to bust the illegal gold buyers.