Union leaders said workers were picketing over the delay in finalisation of the seventh wage revision agreement, originally due mid-2001, the Hindu reported.

During the protest on Monday, union leaders were arrested.

Singareni's mining activities are concentrated in four districts of Andhra Pradesh: Khammam, Adilabad, Karimnagar and Warangal.

The company posted its first profit in 27 years in the 2003-04 financial year.