114 / 2023-06-15 22:00:31

The influence of natural hazards on the safety of underground coal mining in Poland

natural hazards,hard coal mine,safety

The article presents an assessment of the level of mining safety in selected Polish underground hard coal mines in the Upper Silesian Coal Basin (south-eastern part of Poland). In these mines, Upper Carboniferous hard coal seams are exploited by a longwall system with roof collapse at depths of up to 1,200 meters. In these mines, Upper Carboniferous, hard coal seams are exploited by a longwall system with roof collapse at depths of up to 1,290 meters. In 2008, about 84 million tons of hard coal were produced in Poland, and in 2021 about 55 million tons.

The assessment was conducted in relation to the size of the mine, the depth of mining and the occurring natural hazards - gas hazards (ignitions and explosions of methane), fire hazards (endogenous fires), seismic and rock-burst hazards (high-energy seismic tremors and rock-bursts), dust hazards (coal dust explosions), rock and gas outburst hazards (coal, rock and methane outbursts) and collapse hazards (roof rock collapses).

In the Polish coal mining industry, methane, seismic, rock-burst, and fire hazards have the most significant impact on mining safety. These hazards often occur as associated hazards, usually rock-burst and ignition/explosion of methane or endogenous fire/explosion of methane. In 2021, more than 80% of exploited coal seams were in the rigours of gas hazard and 75% of exploited seams were in the rigours of rock-burst hazard.

The analyses were conducted for a 15-year time interval (from 2008 to 2022). The levels of natural hazards at specific mines affect the hamper that exploitation, which has an impact on both the volume of output and the safety of miners employed at the mine.

It was shown that despite a constant increase in the average depth of exploitation - on average every 7 to 8 meters every year, in 2021 it was over 800 meters the number of hazardous events related to the occurrence of natural hazards in the analysed time interval has not shown an increasing tendency. This is due to the fact of reasonable coal mining and adherence to existing laws and rules in this regard.

Under Polish circumstances, the safe underground coal mining operation is a prerequisite for the rational functioning of the mine, both economically and - above all - in terms of protecting the health and lives of miners.

It identified mines with the most difficult geological and mining conditions associated with the presence of natural hazards and attempted to compare them with underground coal mining in other countries.