Evolution law of groundwater system with multiple seams mining in Nanliang Coal Mine

Abstract

Coal mining has an important impact on the groundwater system in the mining area.In the past, more research was distributed on the impact of single coal seam mining on the groundwater system, while the impact on multiple coal seams was rarely studied, especially for water-deficient mining areas in western China.Taking Nanliang Coal Mine as an example, groundwater system evolution theory and physical mechanics simulation method, etc.were used to study the mine hydrogeological structure, mine water inrush change law, mine groundwater flow field evolution, mine groundwater chemical composition change, etc., the groundwater flow system model of Nanliang Coal Mine was reconstructed under the condition of multi-coal mining, and the evolution mechanism of the chemical composition of mine water was initially revealed.The research results showed that when the 2-2 coal seam was mined, the maximum development height of the roof cracking zone was 42.1 m, while when the 2-2 and 3-1 coal seams were repeatedly mined, it increased to 83.1 m.The corresponding stress, displacement, and plastic zone range of the latter was also much larger than the former.This revealed that the repeated mining of multiple coal seams significantly increased the development height of the roof cracking zone, aggravated the variation of the mine's hydrogeological structure, and further, the water-conducting fracture zone changed the natural groundwater seepage paths and communicated the hydraulic connection between different aquifers.As a result, the groundwater flow rate and hydrogeochemical effects were enhanced, and the scale of the groundwater flow system was expanded as a whole, so a natural-artificial composite groundwater flow pattern from rainfall infiltration→seepage in the fracturing zone→water inrush from each coal seam→drainage from the bottom sump was formed.The research can provide a scientific basis for the prevention and control of mine water hazards and the efficient use of water resources in Nanliang Coal Mine, as well as a reference for similar mining areas.

Keywords

• multiple coal seams mining
• groundwater system
• hydrogeological structure
• evolution law
• nanliang coal mine