Physical simulation study on grouting water plugging of flexible isolation layer in coal seam mining

Area of Science:

• Mining Engineering
• Hydrogeology
• Geotechnical Engineering

Background:

• Deep coal mining frequently causes water resource depletion by allowing bedrock water into mine workings.
• Groundwater infiltration into mine sites poses significant challenges to water resource management and operational safety.

Purpose of the Study:

• To investigate a new method for preventing groundwater ingress in deep coal mines.
• To assess the effectiveness of a post-mining grouted fracture network as a flexible isolation layer.
• To provide practical guidance for transitioning to sustainable deep coal mining.

Main Methods:

• Physical simulation experiments were conducted using Maiduoshan coal mine's geological conditions.
• Hydraulic fracturing was employed to create a fracture network in the rock strata above the coal seam.
• Grouting was used to form a flexible isolation layer, and monitoring technologies (stress, flow, displacement) were deployed.

Main Results:

• The study successfully demonstrated the formation of a post-mining grouted fracture network.
• The flexible isolation layer effectively blocked groundwater infiltration into the water-conducting fracture zone.
• Analysis revealed the spatial distribution and evolution of the water-conducting fracture zone, stress variations, and overburden behavior.

Conclusions:

• The fracture and grouting technique for creating a flexible isolation layer is feasible.
• This method offers a viable solution for mitigating water resource loss in deep coal mining.
• The findings support the adoption of safer and greener mining practices in China's western mining regions.