Bulgaria ranks first in Europe in the extraction of copper and gold, data from the Bulgarian Chamber of Mining and Geology shows.
The sector currently employs 24 000 people, with wages rising, according to the chamber's report cited by Money.bg.
Some 600 mining depots have so fat been located in Bulgaria, and coal as the main resource extracted from them.
The union has published the statistics to mark the day of the Bulgarian miners celebrated on Monday.
August 18, the assumption of St Ivan Rilski, was designated as the miners' professional day 110 years ago with a decree of Tsar Ferdinand, issued on the proposal of miners from the western mining city of Pernik.