A history-sheeter along with five truck drivers were arrested under Aslali police station area, though three others managed to escape.
A police team raided the river bed on Sunday night and found illegal mining near Piplaj village on the Aslali-Vatva border.
Police said that at around 2.30 am, they found three JCB machines digging the river bed. The police also found five trucks loaded with sand and arrested seven, including a father-son duo who had hired JCB machines as well as trucks for illegal mining.
A police official said that it is illegal to mine at night and a clear cut guideline stating that mining is illegal between 6 pm and sunrise exists.