Officials in Ratanakkiri province are preparing to take action against an illegal mining site that is said to have been operating since at least 2006 as part of ongoing efforts to reform the sector.

Hun Bunthan, director of the province’s Mines and Energy Department, said that he has been given permission from the central ministry to shut down the O’Yadav district gold mining site.

“We have known about it since a month ago. Their activities are getting bigger and bigger – we are preparing an immediate crackdown,” he said.

He added that efforts to stamp out illegal mining in the province saw authorities take action against a gem-mining site in Bakeo district yesterday, seizing two machines.

Chhay Thy, Ratanakkiri’s provincial coordinator for local rights group Adhoc, said he visited the O’Yadav site – which he estimated occupies about 3 square kilometres of land – on Friday after receiving reports from the local community about the illegal operation.

“We found between 20 and 30 machines in different places with about 200 migrant Cambodian and Vietnamese workers who were digging and grinding the gold without any interception,” he said.

As well as crude mining machinery, Thy said the inspection uncovered chemical substances used to melt the gold.

He said the lucrative business has been operating illegally for at least nine years. “It is still operated today without fear of anyone, but it’s not as big as it was in 2006.”

As part of sweeping reforms to the sector, the government this year awarded its first “community licence” to a group of artisanal miners in Mondulkiri province in a bid to legalise the activities of small-scale miners. It plans to roll out the initiative across the country.

But Thy said workers he spoke to were reluctant to apply for the licence, because they thought the process would be too complicated.

He added that Adhoc would approach relevant authorities today about the operation, which he believes has survived for so long because it has the backing of “powerful people”.

“The authorities should take responsibility for this case since they should not have allowed this work to take place,” he said.

But District Governor Mar Vichet denied that there was any illegal mining in the area.

“In the past, the illegal business existed but it was only on a family scale. Later on, I ordered forces to intercept . . . [so] now it is quiet and they have quit. There is no problem,” he said.

Meng Saktheara, a secretary of state at the Ministry of Mines and Energy, could not be reached yesterday.