The government on Saturday imposed a ban on exports of thermal coal for January because of concerns suppliers could not meet the country's own power demand.

Joko said in an online broadcast that coal miners failing to meet a government requirement to sell 25% of their output to the local market would face sanctions. Their business permit could be revoked, he said.

(Reporting by Bernadette Christina Munthe, Fransiska Nangoy; Editing by Sanjeev Miglani)