When extracting coal seams in Vietnam underground mines, coal pillars are often left unmined for the protection of retained roadways in the longwall mining method. During longwall mining operations, coal pillars are often placed where high-stress concentrations occur in the abutment pressure zone of adjacent panels, especially when extracting seams under hard-to-cave main roof conditions. The instability of coal pillars under the loading of the main roof may cause the roadway to collapse, threatening the safe operation of a coal mine. This paper presents a detailed numerical investigation of the effect of coal pillar width on the stability of retained roadway under hard-to-cave main roof conditions, which has not been fully understood in previous studies. The results indicate that as the width of the coal pillar increases, the peak stress gradually moves from the virgin coal side to the pillar side, and an elastic zone will gradually be formed in the center of the pillar. A pillar width of less than 40 m coal pillars is easily destroyed under the great pressure caused by the hard main roof. A pillar width greater than 40 m creates a safe condition and has enough bearing capacity to maintain the stability of retained roadways. Based on these results, this paper proposes to use an improved longwall mining method where the coal pillars should be mined together with the adjacent panel to reduce coal loss in pillars.
Le, Quang Phuc and Le, Tien Dung
"Numerical simulation on effect of coal pillar width on stability of retained roadway: A case study of Khe Cham Coal Mine, Vietnam,"
Journal of Sustainable Mining: Vol. 23
, Article 1.
Available at: https://doi.org/10.46873/2300-3960.1400
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.