The raids were carried out by 10 CBI officials, who were also assisted by a five-member team from the agency's economic offences wing from Chennai, official sources said.
The CBI action came on the basis of a report of the Deputy Commissioner who was asked by the Central Empowered Committee formed by the Supreme Court into the illegal mining issue, to look into certain illegalities.
The CBI had recently chargesheeted 18 people including Karwar MLA (independent) Satish Sail in the case.
CBI has been investigating the case on the order of the Supreme Court which had set up the CEC.