Workers at closed Cherno More mine, in the region of Burgas, blocked on Tuesday morning the road between Burgas and the resort of Slanchev Bryag (Sunny Beach) to protest against the delay in payment of wages and compensations.

Work at the mine ended earlier in April, leaving its workforce of nearly 300 people without jobs and with unpaid salaries for March.

On Tuesday, a 5-km queue of vehicles was formed as miners gathered on the road despite the torrential rain, local media outlets report.

They called on the management to also pay off all the compensations they are entitled to after their jobs are cut.

The mass layoff of 280 people was not made in compliance with the 30-day notice period provided under Bulgaria's labour code, and Cherno More mines were earlier handed a warning from the local labor inspection authorities.

Delayed salaries have been a problem at the mine for years, resulting in numerous demonstrations and strike action.

One of their underground strikes in 2014 continued for nearly two days.

The management had warned in December that, as problems at the mine were piling up, it would soon become unprofitable.