Iron ore output has dropped nearly 36 per cent a day at a key mine run by state-owned NMDC Ltd since early June after night freight trains were suspended to avoid Maoist attacks, sources said on Wednesday.
"We were maintaining daily dispatches of some 56,000 tonnes, but it has now come down to a level of nearly 36,000 tonnes a day," a senior company official, who declined to be named, told Reuters.
Two other NMDC officials said shipments were cut starting June 5 as they were only nine rail rakes now in use, compared with 14 rakes a week earlier.
The affected mining complex, encompassing two units, in the Bailadila hills of Chhattisgarh, of which Raipur is the capital, had produced 77 percent of the company's total output of 28.52 million tonnes in the year ended March 31, 2009.
NMDC officials said supplies could normalise next week with resumption of night trains, railway and company officials said.
Railway authorities suspended night freight trains following police intelligence alerts that Maoist rebels could target them to mark a week-long revolutionary week they were celebrating in the state.
The insurgents, who say they are waging war on behalf of the poor and the landless against the state, have taken effective control of large swathes of the countryside in central and eastern India, scaring off potential investors while controlling land rich in minerals.
More than 1,000 attacks were recorded in 2009 and 600 people killed with attacks in recent months.
Passenger trains in some parts of eastern India also remain suspended at night after a train in West Bengal derailed and smashed into an oncoming goods train last month, killing at least 145 people.
The rebels ambushed and killed 76 government forces in April in an attack that underscored their growing strength.