The miners halted work last week in support of colleagues who were protesting in the capital Sarajevo against what they said were violations of work and pay regulations.

US power plants are burning more coal amid a global shortage of natural gas.

Glencore is the world’s biggest thermal-coal shipper and its billionaire former boss Ivan Glasenberg has been a firm advocate of the business.

The Hail Creek coal mine leaked an estimated 230,000 tonnes of methane a year in 2018 and 2019, according to researchers.

Some coal miners at top mining regions have caped prices at 900 yuan a tonne.

The detained inspectors issued a safety certificate for the mine in November but had not actually checked the facility.

The coupons are coming after a shortage of the fuel drove up prices and led to widespread power curbs last month.

The state-run company is facing pressure from high diesel prices and an increase in salaries of employees.