Bulgaria's largest coal mining complex Maritsa East incurs daily losses of between 2.0 and 3.0 million levs ($1.3-1.96 million/1.02-1.53 million euro) from an ongoing workers' strike.
Miners at Maritsa East went on strike on Sunday demanding bonuses for the mines' increased output last year.
The strike may cause a delay in payments to staff and suppliers and may interrupt coal deliveries to the country's thermal power plants, state-run Bulgarian news Agency (BTA) reported.
It, however, will not lead to power cuts though it may be reflected in electricity bills later in the year, deputy energy minister Delyan Dobrev told the state-run Bulgarian National Television.
Trade unions with the mines demand that each worker get an extra 1,000 levs ($653/511 euro) as the mines' annual output last year exceeded plans by 6.0 million tonnes.
About 80% of workers have joined the protest, BTA reported, quoting the company's press office.