CAPE TOWN (Reuters) - Illegal miners in South Africa are swallowing unrefined gold and platinum in condoms as a new tactic to avoid arrest for smuggling that is costing the industry $1.5 billion a year, the police told parliament on Friday.

Illegal mining has plagued South Africa’s mining sector for decades, and extends from small time pilfering to global organized crime networks.

The crime costs the industry and government an estimated 20 billion rand ($1.5 billion) a year in lost sales, taxes and royalties, the Chamber of Mines, an industry body, says.

“They are ingesting the amalgam concealed in condoms and this is done for two principle reasons. One is to be able to bypass mine security and the other is also to prevent being robbed by opposing groups,” Brigadier Ebrahim Kadwa, a commander in South Africa’s Hawks organized crime unit, said, showing parliament slides of gold-filled condoms in miners’ x-rays.

Potentially toxic clumps of mercury and gold concentrate can be refined to extract gold once passed through the body.

Illegal mining in South Africa involves a complex criminal web that extends from desperate unemployed workers, many from neighboring countries, to gun-toting gang bosses and front companies exporting refined products to global markets.

“The threat posed by illicit mining and related crimes continues to proliferate across the country,” Kadwa said, adding that the majority of incidents were in gold mines owned by Harmony Gold and Sibanye.

However, hundreds of incidents occurred throughout the country and targeted other minerals such as diamonds and chrome.

High rates of unemployment and a stagnant economy helped entice illegal miners to the dangerous work, which is also being driven by rising commodity prices.

Kadwa said a weakening of the rand currency between December 2015 to April 2016, saw the relative gold price rise, encouraging illegal smuggling.

In February, 22 illegal miners were given lengthy sentences after being found guilty of 577 charges, ranging from theft of gold to racketeering and money laundering.

“This is a landmark moment in the fight against illegal mining in the country,” Kadwa said.