Union Coal and Power Minister Piyush Goyal said on Thursday that there was sufficient supply of coal for the nation's power plants to operate even if there were no mining activities in the next two months."Even if no coal is mined for the next 50 to 60 days, the power industry can rest assured that they would get an uninterrupted supply of coal to keep their plants running," the minister said.The goverment statement comes a day ahead of the September 2 nationwide strike called by central trade unions. "The nation as a whole has sufficient supply of coal," said Goyal at a conference in Mumbai, referring to the possibility of state miner Coal India workers joining the strike.More than a million workers across the country, and across multiple sectors, plan to strike on Friday.Among the trade unions' demands are checking price rise through a pan-India public distribution system, enforcement of labour laws, universal social security cover for all workers, and stoppage of disinvestment in state-run enterprises and banks.They are also demanding revocation of ceilings on payment of bonus and provident fund and increase in the quantum of gratuity.