"The leaders from all five operating central trade unions - INTUC, BMS, HMS, AITUC and CITU in the coal industry -- convened an urgent joint meeting... The notice for proceeding on strike was served to the coal secretary, Coal India chairman and Singareni Collieries chairman," Rashtriya Koyla Khadan Mazdoor Sangh said in a statement.
Their set of demands also includes early settlement of wage negotiations for coal miners and end of contractual system of labour in coal companies, besides withdrawal of decision on closure of mines.
However, the Coal India management could not be reached for comments.
Coal India, which is the largest miner in the world, accounts for over 80 per cent of the domestic coal production.