Water control and prevention technology for the underhand mining face beneath the water-rich bedrock

Abstract

Aiming at the problem of the damage development process of overburden cracks and the prevention of floods in the working face with rich water layer under the influence of the main mining coal seam under the influence of the shallow buried thick loose layer. Taking the 31409 working face of Jinjie Coal Mine as the engineering background, and adopting the analysis method combining theoretical calculation and field measurement, it is obtained that the theoretical height of the overburden water-conducting fracture is 30.9 m to 53.9 m, and hydrological monitoring result indicates that the fissure zone during the mining process only penetrates the base rock aquifer and can not affect the stability of the loose aquifer. Water-rushing model is dominated by bedrock fissures and weathered fissures filled with water, and the groundwater level changes are characterized by “dynamic consumption & lateral replenishment”. The 3DEC software was used to establish a calculation model for the overburden disturbance calculation in the subsurface mining face, which showed that the evolution of the overburden water-transmitting fissures presents three zones: moving fissure area, fixed fissure development area and fissure development dynamic growth area. Based on the hydrogeological characteristics of aquifers near the coal seam, multiple layers, large thickness, high water head, etc., the “three-in-one” flood prevention and control technology has been implemented for the drainage hole layout method, the “zoning and grading” working face water inflow prediction method and the construction of special drainage measures. It effectively alleviates the water inrush hazard of underhand mining face under the rich water layer.

Keywords

• shallow buried coal seam
• rich water strata
• underhand mining face
• water inrush prediction
• flood prevention