Mining Stability Criterion of Weakly Cemented Aquiclude and Its Application

Chen, Chuangju; Zhang, Shizhong; Fan, Gangwei; Zhang, Dongsheng; Chen, Liang; Ni, Huining; Han, Xuesen; Chai, Yujian; Lv, Yuxiang

doi:10.3390/min13010083

Cited by 3 publications

(2 citation statements)

References 30 publications

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“…The stability of weakly cemented aquiclude under mining in the Ehuobulake mine in Xinjiang was studied. The mechanical model of mining stability was constructed, and the influencing factors and criterion of instability were proposed 26 . The fractal geometry theory and discrete element numerical simulation were used to study the evolution law of the fracture network during the layered mining of thick coal seams in the western mining area.…”

Section: Introductionmentioning

confidence: 99%

Overburden failure and water–sand mixture outburst conditions of weakly consolidated overlying strata in Dananhu No.7 coal mine

Zhu,

Li,

Teng

et al. 2024

Sci Rep

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This study presents a case of weakly consolidated strata developed in Dananhu No.7 coal mine. Using a combination of numerical simulation, field measurement comparison, and the critical hydraulic gradient criterion, we investigate the overburden failure and the risk possibility of water–sand mixture inrush during excavation. The following are the principal findings: (1) Weakly consolidated rocks have poor physical characteristics, particularly when they are mudded and disintegrated after encountering water, which may become a favorable source of water–sand inrush; (2) The water-conducting zone develops to a height of 160.5 m with a crack-mining ratio of 15.29 times, extending upward to Toutunhe Formation aquifer. The predictions are consistent with measurements in adjacent mines with similar geological conditions; (3) Cracks without larger subsidence are developed at the front edge of the mining direction, and some parallel stepped cracks behind the goaf could be easily observed. Ground subsidence along the goaf center finally displays a symmetrically wide-gentle U shape; (4) The critical hydraulic gradient of Toutunhe Formation aquifer, aquifer above 3# coal seam, and aquifer of 3#–7# coal seam in Xishanyao Formation is 1.314, 1.351, and 1.380, the actual value is 0.692, 2.089, and 7.418 accordingly. It is inferred water–sand mixture outburst will not occur in Toutunhe Formation aquifer, while the potential risk exists in the aquifers of Xishanyao Formation. Through drainage and depressurization projects, a water–sand mixture outburst accident does not occur during excavation. This study reveals the overburden failure characteristics and the initiation mechanism of water–sand inrush in weakly cemented strata, as well as the internal relationship between them, which provides new research ideas for safe operation in other mining areas with similar geological conditions. The research work has certain practical guiding significance.

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Section: Introductionmentioning

confidence: 99%

Overburden failure and water–sand mixture outburst conditions of weakly consolidated overlying strata in Dananhu No.7 coal mine

Zhu,

Li,

Teng

et al. 2024

Sci Rep

View full text Add to dashboard Cite

show abstract

“…The stability of weakly cemented aquiclude under mining in Ehuobulake mine in Xinjiang was studied. The mechanical model of mining stability was constructed, and the in uencing factors and criterion of instability were proposed (Chen et al 2023). The fractal geometry theory and discrete element numerical simulation were used to study the evolution law of the fracture network during the layered mining of thick coal seams in the western mining area.…”

Section: Introductionmentioning

confidence: 99%

Overburden Failure and Water-Sand Mixture Outburst Conditions of Weakly Consolidated Overlying Strata in Dananhu No.7 Mine

Zhu

Teng

et al. 2023

Preprint

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This study introduces a case of weakly consolidated strata developed in Dananhu No.7 mine, and we investigate the overburden failure behaviour and the risk possibility of water-sand mixture inrush during excavation through an approach of combining numerical simulation, field measurement comparison and criterion of the critical hydraulic gradient for sand-water outburst into working sites. The following findings consist of the main conclusions. The caving zone is approximately 37.3m with a caving-mining ratio of 3.55, and the water-conducting fractured zone is 160.5m with a crack-mining ratio of 15.29 or so. The predictive results are in line with those measured in nearby and similar geological conditions mines. A crack without obvious subsidence is formed at the front edge of mining direction, and some groups of parallel stepped cracks behind the goaf could be easily observed. The subsidence characteristic of ground and below strata along the goaf center transforms an asymmetric into a symmetrical and wide-gentle “U” shape. The critical hydraulic gradients of Toutunhe Formation aquifer, aquifers of 3 coal and 3 ~ 7 coal in Xishandao Formation affected by mining are 1.314, 1.351, and 1.380, the corresponding actual hydraulic gradients are 0.692, 2.089, and 7.418. It is inferred that water-sand mixture outburst will not occur in the Toutunhe Formation aquifer, while the potential risk of outburst exists in the Xishanyao Formation aquifer. Through drainage and depressurization projects, water-sand mixture outburst accidents do not occur during excavation. The research results can lay technical and theoretical foundations for the safety mining of coal mines in western China.

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Development of non-hydrophilic similar materials for weakly cemented rocks and its experimental application in water conservation mining

Gu,

Qi,

Zhao

et al. 2024

Journal of Geophysics and Engineering

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The mining of coal mines in western China needs to focus on protecting groundwater. A non-hydrophilic similar material for simulating the development and hydraulic conductivity of weakly cemented overlying strata fractures was developed. Fine sand, coarse sand, and gypsum are used as aggregates. Paraffin and vaseline are used as binders. The non-hydrophilic material ratios of weakly cemented sandy mudstone and medium-grained sandstone were determined by orthogonal experiments, and used for similar simulation tests. The results show that the non-hydrophilicity of rock-like materials can be adjusted to prevent them from softening and collapsing under the action of water. Non-hydrophilic materials of higher strength and brittleness of rocks can be achieved by adjusting the content of paraffin, fine sand, and gypsum. The non-hydrophilic materials of soft and large particle rocks can be achieved by adjusting the content of paraffin, fine sand, and gypsum. After the coal seam in the similar simulation experiment was extracted, the large area of weakly cemented rock above it undergoes overall settlement and fracture. Although this part is located within the failure zone, there is no macroscopic water conducting cracks generated. The height of the water conducting fracture zone was lower than the height of the fracture zone classified by the traditional ‘three zone’ theory, which is consistent with the on-site measurements. This indicates that the prepared non-hydrophilic material is reliable. The similarity simulation method based on non-hydrophilic materials can enrich the means for studying the fracture and permeability of weakly cemented overlying rocks in coal mines.

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Mining Stability Criterion of Weakly Cemented Aquiclude and Its Application

Cited by 3 publications

References 30 publications

Overburden failure and water–sand mixture outburst conditions of weakly consolidated overlying strata in Dananhu No.7 coal mine

Overburden failure and water–sand mixture outburst conditions of weakly consolidated overlying strata in Dananhu No.7 coal mine

Overburden Failure and Water-Sand Mixture Outburst Conditions of Weakly Consolidated Overlying Strata in Dananhu No.7 Mine

Development of non-hydrophilic similar materials for weakly cemented rocks and its experimental application in water conservation mining

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