Large deformation control of deep soft rock roadways has been a major problem in mining activities worldwide. This paper considers the supporting problem related to large deformation of a deep soft rock roadway in Chao’hua coal mine. The discrete element simulation method (UDEC software) is adopted to simulate a tailgate of panel 31041 in Chao’hua coal mine. The failure patterns of unsupported and primary supported roadway are simulated, and these reveal the characteristics of deformation, stress and crack propagation. The excavation of roadway leads to high deviator stress, which exceeds the peak strength of shallow surrounding rock and causes it to enter the post-failure stage. Tensile failures then initiate and develop around the roadway, which causes the fragmentation, dilation and separation of shallow surrounding rock. The compressive capacity of the primary support system is low, which results in serious contraction in the full section of the roadway. An improved control scheme is put forward for the support of a tailgate. The underground test results confirm that the improved support system effectively controlled large deformation of the surrounding rocks, which can provide references for support in the design of roadways excavated in deep soft stratum.

During the process of close-distance seam group mining, the coal pillar in the upper coal seam is a stress-concentrated area, which leads to a loss of stability of the roadway during mining of the lower coal seam. This lack of stability introduces great safety hazards to coal mines. To solve the problem of stress concentration of coal pillars, the method of gob-side entry retaining by roof cutting is proposed to remove the coal pillar. In this study, FLAC3D was used to analyze the depth and angle of pre-split blasting. LS-DYNA was used to analyze the spacing of the blasthole. Using the methods of theoretical analysis and numerical simulation, we determined that the optimal depth of the pre-split blasting was 6 m, the optimal angle for pre-split blasting was 15°, and the optimal spacing of the blasthole was 500 mm. A field test was carried out in the 1010201 ventilation roadway of the Yuwang Coal Mine, China. The on-site peeping results showed that when the spacing of the blasthole is 500 mm, connecting cracks can form under the action of blasting stress. After the working surface is mined, the roof strata could collapse and fill the gob over time when the depth and angle of the pre-split blasting are 6 m and 15°, respectively.

Landslides are one of the most destructive and common geological disasters in the Tonglvshan mining area, which seriously threatens the safety of surrounding residents and the Tonglvshan ancient copper mine site. Therefore, to effectively reduce the landslide risk and protect the safety of the Tonglvshan ancient copper mine site, it is necessary to carry out a systematic assessment of the landslide susceptibility in the study area. Combining the unascertained measure (UM) theory, the dynamic comprehensive weighting (DCW) method based on the fuzzy analytic hierarchy process (AHP)-entropy weight method and the set pair analysis (SPA) theory, an improved UM-SPA coupling model for landslide susceptibility assessment is proposed in this study. First, a hierarchical evaluation index system including 10 landslide conditioning factors is constructed. Then, the dynamic comprehensive weighting method based on the fuzzy AHP-entropy weight method is used to assign independent comprehensive weights to each evaluation unit. Finally, we optimize the credible degree recognition criteria of UM theory by introducing SPA theory to quantitatively determine the landslide susceptibility level. The results show that the improved UM-SPA model can produce landslide susceptibility zoning maps with high reliability. The whole study area is divided into five susceptibility levels. 5.8% and 10.16% of the Tonglvshan mining area are divided into extremely high susceptibility areas and high susceptibility areas, respectively. The low and extremely low susceptibility areas account for 30.87% and 34.14% of the total area of the study area, respectively. Comparison with the AHP and Entropy-FAHP models indicates that the improved UM-SPA model (AUC = 0.777) shows a better performance than the Entropy-FAHP models (AUC = 0.764) and the conventional AHP (AUC = 0.698). Therefore, these results can provide reference for emergency planning, disaster reduction and prevention decision-making in the Tonglvshan mining area.

In this paper, combined with fuzzy analytic hierarchy process (FAHP), information entropy theory, and set pair analysis (SPA) theory, an improved set pair analysis model (EFAHP‐SPA) for open‐pit mine slope stability evaluation based on entropy method and FAHP is proposed. Taking the east‐side slope of Tonglvshan north open‐pit mine in Daye as an example, the proposed method is verified. First, an open‐pit mine slope stability evaluation index system with 14 indicators in 4 categories, namely the topography and geomorphology, geological structure, hydrogeology, and other factors, have been constructed. Second, the objective weight and subjective weight of each evaluation index are calculated by entropy and fuzzy analytic hierarchy process, and then the comprehensive weight of the evaluation index is estimated based on subjective weight and objective weight. Afterward, the single‐index connection degree between the evaluation index and the evaluation standard of the secondary subsystem is evaluated considering the improved set pair analysis theory, and the comprehensive connection degree of the system is obtained by combining it with the comprehensive weight of each evaluation index. Finally, the confidence criterion is established to discern the risk grade of slope stability in the east‐side slope of the north open pit in Daye Tonglvshan mine. Moreover, case studies and comparisons of the proposed model with fuzzy comprehensive evaluation method and Entropy‐SPA model were performed to confirm the validity and reliability. The results show that the evaluation results of the proposed EFAHP‐SPA model are consistent with the actual situation of open‐pit mines and the evaluation results of entropy‐SPA model and are somewhat different from those of fuzzy comprehensive evaluation method. It indicates that the proposed EFAHP‐SPA evaluation model can objectively evaluate the slope stability of the open‐pit mine.

Mechanical cooling of the entire mining tunnel, widely used in deep coal mines, has a significant energy-intensive consumption, particularly for intelligent mining tunnels. Therefore, localized cooling would benefit the intelligent mining industry. Current studies on the temperature, relative humidity, and air velocity under localized cooling for working protection are still unclear. A modified predicted heat strain model that is appropriate for warm and humid conditions is presented in this article and calculated using MATLAB. Results reveal that air temperature was the primary factor affecting underground miners’ safety. Increasing air velocity would improve the working environment when the thermal humidity index is lower than 32. Reducing total working time and wet bulb temperature would benefit underground miners’ security. For the cooling of intelligent mining tunnels, the recommended air velocity would be 2 m/s, and the maximum wet bulb temperature would be 28 °C for the 6-h working period and 26 °C for the 8-h working period. Results would be beneficial to the cooling of intelligent mining in China.