Efficient determination of gob-side pillar parameters in room-and-pillar mining of medium-thick and inclined coal beds: A case-study of the Quang Ninh Coal Basin, Vietnam

The Quang Ninh Coal Basin is a key supplier of coal products in Vietnam. However, mining of medium-thick and inclined coal beds is complicated by their aggravated geological structure and highly variable geotechnical conditions. The conventional approaches to coal pillar design peg at mostly flat-lying or gently dipping beds, which causes a methodical gap in the determination of pillar parameters for inclined beds. This article puts forward an analytical procedure for the justification of a reasonable width for the gob-side pillars in room-and-pillar mining with regard to the conditions of the Quang Ninh Coal Basin. The research integrates in-mine observations, theoretical analysis and analytical modeling with respect to the key parameters, namely: depth of mining, width of cutting, dip angle of coal beds, density of coal and host rocks, uniaxial compression strength of coal and safety factors. Using these data, the generalized dependences are obtained for estimating distribution of loads on the pillars, and the functional relations are found to characterize variation in width of the gob-side pillars in different geological conditions. The results show that with an increase in the depth and width of cutting, the required width for the pillars grows, while the high strength of coal allows decreasing their size. The parametric analysis identified the joint effect of the geology and design on the pillar stability. The proposed procedure enhances design accuracy, improves safety in operation, decreases coal loss and offers a realistic framework for the optimization of room-and-pillar mining method in the conditions of inclined coal beds. 

Pham Duc Thang, Abramkin N. I., Nguyen Ngoc Minh Efficient determination of gob-side pillar parameters in room-and-pillar mining of medium-thick and inclined coal beds: A case-study of the Quang Ninh Coal Basin, Vietnam. MIAB. Mining Inf. Anal. Bull. 2026;(3):49-61. [In Russ]. DOI: 10.25018/0236_1493_2026_3_0_49.

Pham Duc Thang¹, Cand. Sci. (Eng.),  e-mail: phamducthangmct@gmail.com, ORCID ID: 0000-0002-1049-2403,
N.I. Abramkin, Dr. Sci. (Eng.), Moscow Polytechnic University, Moscow, Russia, e-mail: abramkin57@mail.ru,
Nguyen Ngoc Minh¹, Cand. Sci. (Eng.), e-mail: minhnguyen1986vn@gmail.com, ORCID ID: 0000-0002-1940-5900,
¹ Quang Ninh University of Industry, Quang Ninh, Vietnam.

Pham Duc Thang, e-mail: phamducthangmct@gmail.com.

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