In July, the vigilance department was asked by the state government to investigate illegal mining of manganese ore after opposition parties alleged that it was going on in an area of over 36 hectares in the mineral rich Keonjhar district.

The vigilance department last month arrested eight people, among them mining and forest department officials and a mine owner, for their involvement in illegal mining.

Mayurbhanj is Keonjhar's neighbouring district. Patnaik said some more areas in both districts are likely to be inspected.