The CBI team first picked up mining transporters and workers from various locations and whisked them away to the Government Guest House for questioning, police said.
Earlier, five CBI officials of the team conducted a raid on an apartment of a transporter located at Saibaba Colony and seized documents related to mining, police said.
Former Minister and mining baron Gali Janardhan Reddy and six others were chargesheeted by CBI in a Bangalore court in May in connection with the case.
It had alleged that Reddy and others entered into a criminal conspiracy during 2009-10 to illegally excavate iron ore from various forest areas in Bellary district and surrounding areas.
According to the chargesheet, they excavated iron ore to sell it to various traders and transported the ore to Belekeri port for export purpose causing a wrongful loss of Rs 198 crores to the state exchequer and wrongful gain to themselves.