Comprehensive Water Inrush Risk Assessment Method for Coal Seam Roof

Abstract

In order to prevent coal mine water inrush accidents, it is necessary to appropriately assess the water abundance of coal mines based on drilling and geophysical data. This paper studied a comprehensive risk assessment method of water inrush. First, a water inrush risk index was proposed based on the analytic hierarchy process-entropy method (AHP-EM) and the water-rich structure index was proposed based on the geological data coupled calculation, then weighted two indices above which established the comprehensive water inrush risk assessment method. Secondly, eight factors were chosen as risk control factors of water inrush: core recovery, aquifer thickness, distance from the indirect aquifer to the coal seam, aquiclude thickness, height of water-conducting fracture zone, sand-mud ratio, total layers of aquifer and aquiclude, and the equivalent thickness of sandstone. Finally, the No. 2 coal seam of Dahaize coal mine was taken as the research object, the factors were calculated, and a comprehensive water inrush assessment model was constructed. With site investigation and observation, the water inrush risk assessment model of the No.2 coal seam roof is consistent with the actual mining situation, which verifies the validity of the model. In addition, this method was used to evaluate the water-richness of the weathered bedrock fractured aquifer in the Zhangjiamao coal mine. The practical application of the two mines has verified the generality of the approach. The research could provide scientific assistance for mine water hazard mitigation and mining safety.

Analysis of Potential Water Inflow Rates at an Underground Coal Mine Using a WOA-CNN-SVM Approach

“…Based on the reports of hydrogeological data from 2019 to 2023 by Baodian Coal Mine, such as raising the upper mining limit and the Quaternary aquifer water-yield property research report, private data on hydrology and geology are used to guide coal mine production, and considering the factors affecting water yield of the aquifer and other scholars' [23][24][25] experience in index selection, six factors are selected from the aspects of hydraulic connection characteristics and aquifer lithology, including aquifer thickness (X 1 ), radius of influence (based on the drilling diameter of 91 mm and the pumping water level drop of 10 m) (X 2 ), normalized drawdown (X 3 ), permeability coefficient (X 4 ), core recovery percentage (X 5 ), and the proportion of clay thickness to lower layer thickness (X 6 ). The thematic map of evaluation indicators is shown in Figure 2.…”

Risk Assessment and Zonation of Roof Water Inrush Based on the Analytic Hierarchy Process, Principle Component Analysis, and Improved Game Theory (AHP–PCA–IGT) Method

“…Compared with the EM, critical method, and other methods, PCA is more suitable for indicators with high correlation and uncertain quantity. The PCA method rearranges and combines the various indicators sorted out and reduces dimensionality, resulting in some principal components with low correlation [35,36]. Each principal component is a linear combination of the original indicators, and the basic conditions for the smooth operation of PCA are KMO value > 60% and p-value < 0.05 for the Britlet test.…”

Risk Assessment of Water Inrush from Coal Seam Roof Based on the Combined Weighting of the Geographic Information System and Game Theory: A Case Study of Dananhu Coal Mine No. 7, China

“…Ruan et al [15] expanded and improved the analytical hierarchy process using the Dempster-Shafer evidence theory to obtain weight coefficients for influencing factors and used this to show a new model of assessing the risk of water inrush in the Wangjialing Coal Mine. Sun et al [16] used the hierarchical analysis method-entropy value method (AHP-EM) to propose a water inrush risk index, and the water-rich structure index was proposed based on geological data-coupled calculations, which were then weighted to establish a comprehensive water inrush risk assessment method.…”