District Revenue officer Prasanna Ramaswami said the mishap occurred at 1.30 AM due to the heat generated and the conveyor belt carrying coal caught fire.
The conveyor belt operator, Nallathambi (40) died on the spot, he said.
The injured have been hospitalised, the official said, adding, the fire was extinguished after seven hours.
The 400 metre long belt was damaged and coal burnt, he said.
The 840 MW thermal station has four units each with 210 MW capacity.
