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Coal bump, a common dynamic disaster in mining of deep coal resources, its assessing and predicting is an important component in safety management. This paper presents a model to assess and predict coal bump risk based on multiparameter indices. A new energy accumulation index S was proposed by considering acoustic emission and electromagnetic emission signal characteristics in mine shocks. Combined with indices E (energy of microseisms) and N (frequency of microseisms) of microseismic monitoring, a static and dynamic coal bump risk assessment and prediction model was established. We studied coal bump events that occurred during extraction in 311305 working face of Bayangale coal mine in Inner Mongolia, China. We obtained the acoustic emission and electromagnetic emission signal distribution and change law, using principal component analysis method and density ellipse to establish the index S. A typical precursory of coal bumps is that AE and EME strength has obvious fluctuation period of 3-4 days, index S showing an obvious decreasing trend, while the time-series curve of the microseismic energy is relatively stable, and the vibration frequency curve has a significant upward trend. After predict the potential coal bump risk and its area of occurrence, large diameter drilling (Φ150 mm) on-site was used to relief pressure concertation in coal seam and roof. The results demonstrate that this model based on multiparameter indices is capable of quantitatively prewarning rock burst risk. [ABSTRACT FROM AUTHOR]

The Kubuqi Desert is the seventh-largest desert in China. Under the leadership of the central, autonomous region and local governments, the ecological situation has undergone historic changes. In this paper, we select Hangjin Banner and Dalate Banner, which have the most widely distributed deserts and use 347 households as the research perspective to construct the evaluation index system of the government's ecological environment governance effect. The entropy method is used to evaluate the governance effect, and the ordinary least squares and quantile regression are used to compare the evaluation differences of different publics. The research found the following. (1) The public believes that the government's ecological governance measures have achieved good results in the third-level index analysis. The ecological environment in the desert area has been significantly improved; that is, the survival rate of trees has increased, the area of vegetation coverage and vegetation types have increased, and the frequency of sandstorms has decreased. However, the intensity of sandstorms and the flow of water sources did not change significantly. The various types of public income have increased significantly compared to before the governance. The public takes the ecological priority as the concept and actively participates in the government's governance implementation, which means that the ecological awareness and behavior are higher. (2) Among the second-level index, the weights and scores in descending order are public economic characteristics: 45.53% and 0.4840, public ecological behavior: 25.62% and 0.1682, public ecological effect perception: 18.35% and 0.1240, and public ecological awareness: 10.51% and 0.0291. The comprehensive evaluation result is 0.8054, which is in the first grade, and the effect is excellent. (3) The public comprehensive evaluation results of the two regions are similar. Hangjin Banner is 0.8209 and Dalate Banner is 0.8557, both in the first grade. The effect is excellent. (4) In the OLS regression results, gender has a significant positive impact on evaluating the government's ecological environment governance effect. Age, ethnicity, and occupation have a significant negative impact. As the quintile increases, the influence of gender, age, and ethnicity first increases and then decreases. The maximum regression coefficient of gender at the 50% quantile is 0.714, which has a significant positive effect. Age has a significant negative impact at each quantile. The regression coefficient of ethnicity at the 50% quantile is the highest -0.357, which has a significant negative impact. Occupation only has a significant negative impact at the low quintile. [ABSTRACT FROM AUTHOR]

There are few studies on the management methods of large-scale goaf groups per the specific surrounding rock mass conditions of each goaf. This paper evaluates comprehensively the stability of the multistage large-scale goaf group in a Pb-Zn mine in Inner Mongolia, China, via the modified Mathews stability diagram technique. The volume of each goaf to be backfilled was quantitatively analyzed in the combination of theoretical analysis and three-dimensional laser scanning technology. The corresponding mechanical characteristics of the filling were determined by laboratory testing while formulating the treatment scheme of the large goaf group using the backfill method. The applicability of the treatment scheme using the backfill was verified by the combination of the numerical results of the distribution of the surrounding rock failure zone and the monitored data of the surface subsidence. The research results and treatment scheme using the backfill can provide a reference for similar conditions of mines worldwide. [ABSTRACT FROM AUTHOR]

Roof-breaking characteristics and ground pressure behavior of the coalface are instrumental in guiding deep Jurassic coal seam mining, in particular in the Shaanxi and Inner Mongolia regions of China. A thick-plate mechanical model (TPMM) of the main roof was developed and applied to the case study of 21102 first-mined coalface (FMC) of the Hulusu Coal Mine (HCM) in the Hujirt Mining Area (HMA), China. A theoretical analysis performed via the developed model revealed that the first and periodic breaking intervals of the main roof were 40.6 and 25.0 m, respectively. The roof failure occurred in the tensile mode, was controlled by the internal stress σ x in the rock strata, and started from the center of the long side with the fixed support in the goaf. The field measurement of roof weighting was also performed for the coalface advance from zero to 400 m. The measurement results showed that the first weighting average interval was 41.4 m, and the average interval of periodic weighting was 22.0 m, which agreed with the theoretical calculation and proved the proposed model's feasibility. Finally, the frequency distribution features of the hydraulic support working resistance in the FMC were analyzed statistically. The results showed that the ZY10000-16/32D supports could adapt to the mining geological conditions of the FMC. However, the margin of the rated working resistance of supports was still small. Thus, roof management enhancement during the mining process was strongly recommended. These research findings could offer theoretical guidance for safe and high-efficiency production in the coal mines under similar geological conditions. [ABSTRACT FROM AUTHOR]