Study Finds Rock Discontinuity Density Shifts Mining Overburden Failure Mode and Lowers Critical Width-to-Depth Ratio

A paper published June 3 models how the density of rock-mass discontinuities influences surface subsidence caused by underground coal mining. 1038/s41598-026-55895-x. The authors report that higher discontinuity density shifts the dominant overburden failure mode from intact-rock deformation to block sliding.

This change reduces the reliability of uniaxial compressive strength of intact rock as a sole predictor of subsidence magnitude. The paper states that the applicability of strength-based analogy methods holds primarily when discontinuity densities are comparable between sites.

Higher discontinuity density also lowers the width-to-depth ratio required for critical mining, which the authors link to the delayed and attenuated subsidence observed in deep coal seams of the Ordos coalfield.

Wanxin Pan, Yaqiang Gong, Wenbin Deng, Guangli Guo, Yuyang Wan, and Naseer Muhammad Khan conducted the work. Pan, Gong, Deng, and Wan are affiliated with the College of Civil Engineering and Architecture at Xinjiang University in Ürümqi. Gong and Guo are also affiliated with the State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering at China University of Mining and Technology in Xuzhou; Guo holds an additional affiliation with that university's School of Environment and Spatial Informatics.

Khan is affiliated with the National University of Sciences and Technology in Islamabad. Yaqiang Gong and Wenbin Deng are listed as corresponding authors. The study received funding from the National Natural Science Foundation of China under grant 52404188, the Xinjiang Uygur Autonomous Region Natural Science Foundation under grant 2024D01C244, the Tianchi Talent Recruitment Program of Xinjiang Uygur Autonomous Region under grant TCYC2025, and the National Key Research and Development Program of China under grant 2023YFC3804200.