Underground coal mining is the core process in coal resource development, and the choice of production techniques directly affects mining efficiency, cost control, and safety. With increasing geological complexities and growing resource demand, modern underground mining has evolved into a multi-technique system, covering tunnel layout optimization, surrounding rock dynamic control, intelligent equipment application, and green mining process innovations. So, what are the underground mining production technologies in coal mines?
Deep Mine Mining Technology
Deep mine mining refers to the extraction of coal from mines over 800 meters deep. These mines face multiple challenges, such as high gas emissions, high ground temperatures, and high geological pressure. However, with technological advancements, deep mining is encountering new opportunities.
- Rational Tunnel Layout: In deep mines, optimizing tunnel layouts is key to improving mining efficiency. By optimizing the tunnel layout, the tunnel excavation volume can be reduced, and the resource recovery rate can be improved.
- Efficient Support Technologies: Aiming at the characteristics of high stress and large deformation of the surrounding rock in deep mine shafts, we adopt high-efficiency support technology such as U-type steel retractable bracket and anchor support, which can effectively control the deformation of the surrounding rock and guarantee the stability of the roadway.
- Intelligent Ventilation Systems: Deep mines have high ground temperatures and are difficult to ventilate. The intelligent ventilation system can adjust the ventilation volume in real time according to the underground environment to ensure fresh air and reduce the risk of heatstroke for operators.
Tunnel Layout Technologies
Tunnels are the main passageways in underground mining, and their layout directly impacts mining efficiency and safety.
- Multi-Tunnel Layout: In areas with large mining volumes, laying out multiple tunnels to form a tunnel network can significantly increase mining efficiency. It also helps to distribute pressure, enhancing tunnel stability.
- Optimized Tunnel Cross-Section Design: The tunnel cross-section size should be designed based on transportation equipment, ventilation requirements, and other factors. It ensures that the tunnel meets transportation needs while maintaining good ventilation. The use of advanced support equipment, such as hydraulic supports, improves support quality and reduces tunnel maintenance costs.
- Intelligent Tunnel Monitoring: Utilizing technologies such as the Internet of Things (IoT) and big data, real-time monitoring of tunnels can help detect and address issues like tunnel deformation and support failure, ensuring safety and smooth operations.
Surrounding Rock Control Technology in Mining Areas
The stability of the surrounding rock in mining areas is fundamental to the safety of underground mining operations.
- Hard Roof and Broken Rock Layer Treatment: For hard roofs, techniques like pre-split blasting and water injection softening are used to reduce roof hardness and minimize the risk of roof collapse. For fractured rock layers, grouting reinforcement and metal mesh supports are employed to improve the integrity of the rock layers and prevent rock falls.
- Dynamic Monitoring and Early Warning: A dynamic monitoring system for surrounding rock can track deformations and stress changes in real time, providing early warnings in case of anomalies, giving time for preventive measures.
- Scientific Support Plans: Utilizing the Internet of Things, big data, and other technical means, real-time monitoring of the roadway, timely detection and treatment of roadway deformation, support failure, and other issues, to ensure that the roadway is safe and smooth.
Full Mechanized Top-Coal Caving Technology
The stability of the quarry perimeter rock is the basis for the safety of underground mining operations.
- Type II Steel Beam Top-Coal Caving: This technique involves constructing stable supporting frameworks and using hydraulic props to increase support strength. When combined with blasting to drop coal, it achieves efficient extraction, especially in areas with moderate coal seam thickness and good roof conditions.
- Slippage Support Top-Coal Caving: Using sliding combinations of top beams and supports, this method allows safe and efficient mining of top-coal. It is particularly suited for steeply inclined and thick coal seams, and can adjust the position of supports to accommodate coal seam changes, improving both safety and efficiency.
“Three-Under” Mining Technology
The “Three-Under” mining technology is used in coal extraction beneath water bodies, buildings, and railways. It involves special techniques for mining in areas that impact these features.
- Study of Rock Layer and Ground Movement Patterns: By analyzing in detail the rock and surface movement laws caused by underground mining, a scientific and reasonable mining plan is formulated to reduce the impacts on water bodies, buildings, and railroads.
- Protective Measures and Monitoring: During the mining process, a series of protective measures are taken, such as installing waterproof layers and reinforcing the foundations of buildings. At the same time, a real-time monitoring system is set up to monitor the mining process in its entirety to ensure safety.
- Ecological Restoration and Compensation: After the end of mining, ecological restoration and compensation will be carried out in the affected areas to restore land functions and protect the ecological environment.
Conclusion
Coal mine underground mining production technology is a complex and refined system that includes deep mine mining, tunnel layout, surrounding rock control, full mechanized top-coal caving, and “Three-Under” mining technologies. With continuous technological advancements and innovations, coal mining will become more efficient, safe, and environmentally friendly. For coal enterprises, mastering and applying these technologies not only boosts mining efficiency and economic benefits but also lays a solid foundation for sustainable development. In the future, driven by the dual carbon goals, underground mining technology will further evolve toward low-carbon, resource-efficient, and full-lifecycle management, providing strong support for global energy security and sustainable development.
