Raipur, March 22: Targeting the National Mineral Development Corporation (NMDC) for the third time in two months, Maoist guerrillas triggered six blasts at installations of the iron ore producer in Dantewada district and carried away explosives.

The rebels also blew up part of an Essar pipeline, used to carry iron ore from Kirandul to Visakhapatnam, affecting transportation operations.

Around 11.30 last night, more than 300 armed rebels raided the crusher units of two private contractors near Kirandul, about 450 km south of the capital, and took the employees hostage.

The rebels set off three explosions in one unit and two in another before setting three tractors on fire. They left with a huge quantity of explosives. ?The exact quantity of the explosives looted is yet to be established. But it won?t be small,? a police official said.

The guerrillas released the employees before leaving.

An hour later, around 12.30 am, the rebels raided the downhill conveyor belt unit at deposit 14/11C of the NMDC and detonated an explosive. The roof of the unit blew up before the belt, which was moving, caught fire.

Sources said the employees stopped the machine immediately after spotting the fire. The alert staff helped avert a major mishap, said an official, as there was the possibility of huge load crashing down had the belt broken in the impact of the fire.

A 20-m stretch of the belt was destroyed. ?It would take at least two days to repair the fault. Till then, transportation of iron ore from the mines will remain suspended,? another NMDC official said.

Work at the unit have come to a standstill while the extent of the damage to the conveyor belt is likely to run into crores. No official, however, wanted to speak on this.

Operations had been stepped up as the year-end was approaching, but the task (of meeting targets) would now become difficult, said sources.

In another strike, the rebels caused partial damage to an Essar pipeline near Madari, about 7 km from Kirandul, by blowing it up. It would take at least a day to restore iron ore transportation, said sources.

Iron ore purchased by Essar from NMDC is transported to Visakhapatnam, from where it is shipped to its Hazari steel plant in Gujarat.

Barring the one at Madari, all six blasts took place within 3 km from Kirandul. The blasts were so powerful that people could hear them from the township.

This is the first time Essar property has been targeted.

The rebels left behind pamphlets at several places, reiterating that their aim was to force the end of Salwa Judum, the government?s anti-Maoist campaign, and withdrawal of central forces from the state.

This was the third rebel attack on the NMDC in the past two months.

On March 8, the Maoists had damaged a 50-m belt at the NMDC?s Bacheli facility, about 10 km from Kirandul.

Earlier on February 9, the rebels had raided the corporation?s Hiroli magazine and looted about 50 tonnes of explosives. Eight security personnel were killed and as many injured in the incident.