Bhubaneswar, Nov 6 - The vigilance department in Orissa plans to register criminal cases against more people as it has found evidence of their involvement in a multi-crore mining scam in two districts of the state, an official said Friday.

"In a week or so, we will be able to lodge some more criminal cases," said Anup Kumar Patnaik, director, vigilance department.

He, however, declined to name these people or the exact number of cases the department plans to register, saying it may hamper the investigation.

In July, the vigilance department was asked to investigate after opposition parties produced documentary evidence of large-scale illegal mining in the mineral-rich Keonjhar district.

Patnaik said the vigilance sleuths have already raided seven mines in Keonjhar and its adjoining Mayurbhanj districts and have found evidences of the violation of government rules.

He said four criminal cases against mine owners, forest and mine department officials have already been registered in August in which eight people were arrested.

"Some of the mines we raided were very big. They spread over a 150 km to 300 km area. It is also a complicated and lengthy investigation process," Patnaik said.

"We are verifying records involving the revenue and mines department officials," he said, citing them as the main reasons behind the delay in registering criminal cases.

Meanwhile, a five member team of the opposition Bharatiya Janata Party (BJP) led by senior party leader Balbir Punj Thursday visited Keonjhar district to make an on the spot inquiry into the alleged mining scam.

The team blamed the ruling Biju Janata Dal (BJD) for the mineral theft and smuggling, saying that it was not possible without the patronage of ruling party politicians.

The BJP and Congress have been demanding a probe by the Central Bureau of Investigation (CBI) in to the scam, suspected to have run to several hundreds of crores of rupees. (IANS)