Assistant Geologist Dattatraya Bhave, who was suspended along with five other officials on September 7, hung himself at his residence in Ponda town, they said.
According to his family, Bhave was humiliated, mentally tortured and harassed by the department after the suspension, which forced him to take the extreme step.
Chief Minister Manohar Parrikar said he has asked local deputy collector to initiate an inquiry into the suicide.
"I am pained with the loss of officers. Suspension does not mean punishment. We have kept these officers away because they should not be tampering with the evidence," he said.
The Goa government, after suspending the licences of all the mining leases on recommendations of the Commission, had put six senior officials from state Mines and Geology department under suspension.
All the officers were asked to report at the South Goa collector's office in Margao city.