Five trade unions of Coal India have served notice for a one-day strike on August 18, the state-owned company said on Tuesday, adding that efforts will be made to avert the stir.

"Five trade unions of CIL... served notice of one-day strike in CIL and its subsidiaries on August 18, 2020...," the public sector undertaking (PSU) said in a filing to BSE. Efforts would be made to avert the strike, it added.

Coal India (CIL) worker unions affiliated to five central trade unions have decided to go on strike against the proposed divestment or buyback of shares of the PSU, a union leader had earlier said.

The unions are protesting against commercial mining and also demand the withdrawal of "disinvestment or buyback of shares by Coal India immediately", the president of Hind Mazdoor Sabha (HMS)-affiliated Hind Khadan Mazdoor Federation had said.

The unions had observed a three-day strike from July 2 to protest against commercial mining of coal.

CIL had earlier said it managed to clock an average daily production of 44 per cent and average attendance of nearly 36 per cent during the three-day strike called by worker unions last month.

Coal India accounts for over 80 per cent of domestic coal output.