Classification of coal seam cutting by shearer picks

The underground coal seams exhibit various changes in spatial distribution, and based on their spatial geometry and material characteristics, mining opportunities encounter different requirements for coal seam cutting functions.

(1) Cutting thick and thin coal seams. The thickness of coal seams is divided into six levels, namely extremely thin coal seams with a thickness of less than 0.8 meters, thin coal seams with a thickness of 0.8-1.3 meters, medium thick coal seams with a thickness of 1.3-3.5 meters, thick coal seams with a thickness of 3.5-5 meters, ultra thick coal seams with a thickness of 5-8 meters, and extra thick coal seams with a thickness greater than 8 meters. The thickness of coal seams requires functional requirements for the minable height of the shearer, which is the most important functional characteristic of the shearer.
(2) Cutting of inclined coal seams. The inclination of coal seams is divided into four levels, namely nearly horizontal coal seams with an inclination angle less than 8 °, gently inclined coal seams with an inclination angle of 8 °~25 °, moderately inclined coal seams with an inclination angle of 25 °~45 °, and steeply inclined coal seams with an inclination angle greater than 45 °. The coal mining machine working in coal seams with an inclination angle greater than 35 ° is called a large inclination angle coal mining machine, which requires high traction force, strong climbing ability, reliable anti slip braking device, and equipped with a backup anti slip hydraulic winch.
(3) Cutting of long and short coal seams. According to the occurrence conditions of coal seams, it can be divided into long wall mining with a working face length greater than 50 meters and short wall mining with a working face length less than 50 meters. They have special requirements for the walking mode of the shearer and the layout of cutting tools. Long wall shearers generally use guide rail traction and side cutting, while short wall shearers generally use track walking and front cutting.
(4) Cutting of soft and hard coal seams. Coal seams are divided into 5 levels based on their hardness, namely, extremely hard coal seams with f ranging from 4.0 to 5.0, hard coal seams with f ranging from 3.0 to 4.0, medium hard coal seams with f ranging from 1.5 to 3.0, soft coal seams with f ranging from 0.8 to 1.5, and extremely soft coal seams with f ranging from 0.5 to 0.8. The shearer for cutting coal seams with f greater than 3 should meet the functional requirements of high-power and hard cutting teeth in the cutting section.
(5) Cutting of undulating coal seams. Due to the influence of geological structural factors, the bending deformation of coal seams causes changes in thickness. Therefore, it is required that the coal mining machine has adjustable height rocker arms and automatic height cutting functions to achieve contour cutting of coal seams.