thick-seam mining

Thick-seam mining is an underground coal extraction method used for seams thicker than approximately seven meters. When seams exceed this thickness, they are typically divided into multiple slices, each three to four meters thick. These slices are then mined using methods like longwall, continuous, or conventional mining. The slices can be extracted in ascending or descending order. If roof conditions or the risk of spontaneous combustion necessitate it, the mined void is backfilled, with the backfill material serving as an artificial floor or roof for subsequent slices. However, caving is the preferred practice. In certain conditions, high-pressure water jets can be used to fragment soft coal or friable bands in thick seams, a technique known as hydraulic mining, which is practiced extensively in the Kuznetsk Basin of Siberia.1