The Zabukovica coal mine received its first underground mining claims as early as 1799, which marked the beginning of organised coal mining in the area. Later, other coal outcrops in the Oligocene layers—similar to those in the Zasavje region—also attracted interest. These had already developed before 1850 into the Liboje, Pečovnik and Štore coal mines, which lie to the east of Zabukovica. An important historical milestone was the construction of the Southern Railway (Vienna-Trieste double-track line), which reached Celje in 1846 and Ljubljana in 1849. This gave strategic importance to the coal mines south of Celje - coal became a key energy source for industry, transport and households.

The coal bearing Oligocene strata (conglomerates, sandstones, siltstones, clays and marls) crop out in a narrow, tectonically confined valley belt south of Celje, between Triassic carbonate and magmatic rocks. The coals of this area were considered to be of high quality brown coal in their time - slightly better than those from Zasavje (Trbovlje, Zagorje, Hrastnik), but similar to those from Laško. The coal was suitable for industry, transport, power generation and about 10 % for general (domestic) consumption.

The coal seam thickness reached up to 7 meters, with two barren interbeds less than 0.5 meters thick. The upper part of the seam was the best. The entire run of mine coal had a calorific value of 12.6 MJ/kg at 24.4% moisture and 26.8% ash, with a moderate sulphur content averaging 1.65%. According to current criteria (ECE UN – United Nations Economic Commission for Europe), this coal would, based on its ash content, be classified as brown coal or meta lignite up to low quality sub bituminous coal with a significant sulphur content (above 1.5%).

Coal mines were gradually closed down due to several factors: depletion of reserves, difficult mining conditions, water inflows from the Triassic basement and the quality of the coal. Zabukovica coal mine ceased production in 1966, Liboje (also known as Zabukovica-Liboje) operated until 1972 and Pečovnik ceased operations after a catastrophic water intrusion on 13 December 1959, while Nove Štore had already closed in 1926. Due to challenging mining geological conditions, production was sometimes temporarily suspended in individual mines, but then resumed again.

Coal in this region, much like in many other parts of Zasavje, was an important source for the development of glassmaking, brickmaking and ceramic industries. After the Second World War, an industrial activity developed south of Celje under the common name of Montana, combining all the above-mentioned activities. Montana has transformed from a mining tradition into a modern production and is today a successful company for the extraction and processing of non-metallic minerals such as zeolite tuff and bentonite. But it all started nearly 200 years ago with coal in these parts - further proof of how former mining regions have become models of successful, diversified development in the broadest sense, from culture to high tech industries (Idrija, Mežica, Jesenice, Zasavje, Velenje …).

Prepared by mag. Andrej Lapanje and dr. Miloš Markič