Police said the SI, Muthukrishnan who was injured in the attack at Thenaputhukottai, has been admitted to hospital.
Four lorries were seized and a search is on for five persons, including one Duraipandi who attacked the team, they said.
Duraipandi had obtained a licence for mining sand in a "Patta land"(Private land). However he was mining sand indiscriminately, violating the licence condition.
The gang members assaulted the police team, including the Sub-Inspector who suffered concussion in the attack.
Police action against illegal sand mining has been intensified after the former Collector of the district, Sagayam was appointed to probe into the illegal sand mining.