TITLE:
Mechanism and Control Technology of Workface Pressure Manifestation under Different Types of Overlying Coal Pillars
AUTHORS:
Shiyao Jia, Hao Wang, Wen Wang, Sushe Chen, Wei Wang, Honglong Liu
KEYWORDS:
Overlying Coal Pillar, Workface Pressure Manifestation, Ground Control, Multi-Seam Mining
JOURNAL NAME:
World Journal of Engineering and Technology,
Vol.13 No.2,
May
14,
2025
ABSTRACT: Based on the relative spatial characteristics of overlying coal pillar and underlying mining faces, three types of coal pillar mining workfaces were classified as vertical coal pillars, parallel coal pillars, and oblique intersecting coal pillars. Taking the geological conditions of comprehensive mechanized caving mining face under the overlying coal pillars in Buertai Mine Shendong Coal Group as an example, the characteristics, occurrence mechanisms, and prevention and control technologies of mine pressure manifestation under three types of coal pillar mining workfaces were studied. According to the mine pressure manifestation data of the 4-2 coal seam mining face in Buertai Coal Mine, it was found that when there is stress concentration caused by the remaining 2-2 coal pillars in the overlying coal seam, the pressure manifestation on the 4-2 coal seam mining face varies from strong to weak as follows: mining-out of the parallel coal pillars, mining-in of the parallel coal pillars, and vertical coal pillars in the middle area of the mining face. Based on the geological characteristics of the strata between the 2-2 coal seam and 4-2 coal seam, the fracture evolution characteristics, such as “O-X” shape, of the 4-2 coal mining face roof were analyzed. It was pointed out that the spatial stability of the “fan-shaped lever” under the stress concentration of the overlying coal pillars is the main control factor determining the load of the mining face shield, which is the mechanism of the pressure manifestation of the underlying mining face when mining under the parallel coal pillars. For the vertical coal pillars overlying the mining face, a coal pillar stress transfer model based on the foundation beam was proposed, which revealed the composite fracture mechanism of rock mass between the overlying vertical coal pillars and the underlying coal pillars. Taking the pressure prevention and control in the mining faces 42106 and 42108 under the coal pillars in Buertai Coal Mine as cases, the strong mine pressure prevention and control technology under the overlying coal pillars was introduced. The on-site pressure prevention outcomes were good.