Johannesburg - A multibillion-rand international gold theft and smuggling syndicate was bust in Johannesburg yesterday, revealing the lavish lifestyle of thieving miners.

Farms, extensive herds of cattle and luxury homes and vehicles belonging to the miners - who earn no more than R11 000 a month each - are to be seized within days.

Hawks officers and mine security officials arrested 18 miners yesterday in a raid on a Gauteng gold mine - the culmination of a six-month clandestine police operation.

The men, who work at Sibanye Gold Mine in Carletonville, are believed to be responsible for the theft of gold worth more than R2-billion from the mine in the past year.

The gang is believed to have links to syndicates operating between Africa and the Middle East and Asia.

The theft allegedly occurred at the mine's metallurgical plant, where gold separation occurs.

A police source said the suspects had used specially designed bags fitted inside their overalls to steal the material.

"It [the material] is known as 'concentration', a sandlike substance containing significant amounts of gold," said the source.

"They would remove it from the mine and take it to secret locations for partial processing before it was moved by other syndicate members.

"Estimates show that on average R200-million worth of gold was being stolen every month from the mine. That works out to billions of rands a year.

"This is a highly organised syndicate, with this mine not the only one affected."

At the African Mine Security Summit in April Neil Metzer, the security coordinator of the South African Chamber of Mines, revealed that in 2013 illegal mining had cost the economy nearly R8-billion in revenue.

Another police source said the miners used the money to expand their wealth at their homes in Eastern Cape and KwaZulu-Natal.

"They bought farms, huge herds of cattle, expensive cars and other luxuries, all clearly living beyond their means."

Sibanye Gold spokesman Thabisele Phumo declined to comment on the value of stolen gold: "Certain results are outstanding and given the state and nature of the investigation we are not in a position to confirm the value."

The theft had been noticed in November, she said.

Hawks spokesman Captain Paul Ramaloko said two miners were arrested in December during a surveillance operation near the mine.

"The men were caught in possession of several thousand rands worth of the gold-bearing material," he said.

Ramaloko said yesterday's arrests were made after a six-month surveillance operation, during which the suspects' activities were monitored. "The alleged theft occurred while the suspects were on duty."

"After the miners removed the gold-bearing material, those who were off-duty would collect it, usually late at night from where it had been dumped."

Information showed that the suspects had been thieving for more than a year, Ramaloko said.

"Although nothing was recovered today the suspects have been positively linked to the theft."

Ramaloko declined to say where and how the gold was being sold.

"The investigation is sensitive. [The gold] is destined for the black market. That is all I can say."

The Asset Forfeiture Unit was working with police to freeze and seize the suspects' assets, he said.

"These men have been living lavish lifestyles. On the mines they live in hostels, but at their homes in Eastern Cape and KwaZulu-Natal, they have farms, luxury houses and cars and cattle . amazing assets."

The suspects would appear in the Oberholzer Magistrate's Court, near Carletonville, tomorrow on charges of theft and dealing in gold-bearing material, Ramaloko said.