Maoists on Friday exploded a bomb in Meghatpur mine and planted another at Kiribur, both run by public sector SAIL along the Orissa-Jharkhand border.
The attack comes hours after the Maoists blasted rail tracks in Jharkhand's West Singhbhum district that derailed the Tata-Bilaspur passenger train leaving two passengers dead.
Senior officials in Kirbur told PTI that a group of armed Maoists stormed into the loading point in Meghatpur mines on the Orissa side and exploded a bomb damaging the conveyor belt.
Loading and unloading of iron ore was severely affected at Meghatpur mines under the Steel Authority of India (SAIL) as a result.
In the second incident, the ultras planted a bomb in the conveyor belt in Kiribur mines, about 15 km from Meghatpur and 120 km from Rourkela on the Jharkhand side, but it did not explode, the sources said.
Police and CRPF personnel defused the bomb.
There was no report of any casualty.