No-Pillar Gob-Side Entry Retaining Mining Method
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Solution Overview
Problem
Current coal mining methods require numerous roadways and retained pillars, leading to coal resource loss, spontaneous combustion, ground pressure concentration, and rock bursts, while existing no-pillar methods face air pollution issues and still necessitate pillar retention for staging and isolation.
Innovation Solution
A no-pillar and gob-side entry retaining mining method that constructs main and auxiliary shafts, upper and lower roadways, and inclined intake and return roadways to form a ventilation system, allowing for downward and upward inclined mining without area division, using belt conveyors and monorail hoists for coal transport and equipment movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional mining methods are used with division into stages and sections, then mining safety and control are improved, but coal resource loss increases and numerous pillars must be retained
Solution Approach 1:
The mine is divided into multiple mining faces along the inclination direction, with each face being mined independently. This segmentation allows continuous mining operations without requiring pillar retention between faces, as each face has its own access roadway and ventilation system.
Solution Approach 2:
The mining method utilizes the inclination dimension of the coal seam to create multiple mining faces at different elevations. By mining along the inclination rather than horizontally, the method eliminates the need for pillar retention in the traditional horizontal direction, thereby reducing coal loss while maintaining safety.
2Ease of operation
If numerous roadways are constructed for mining operations, then mining accessibility and ventilation are improved, but construction cost and time increase
Solution Approach 1:
The main roadway serves multiple functions: it provides access to multiple mining faces, acts as a ventilation corridor, and serves as a transport route for equipment and coal. This multi-functionality reduces the total number of roadways needed while maintaining operational accessibility.
Solution Approach 2:
Access roadways and ventilation roadways are merged into a single main roadway structure. The same roadway that provides physical access to mining faces also serves as the primary ventilation corridor, eliminating the need for separate dedicated roadways for each function.
3Reliability
If pillars are retained between mining areas and stages, then safety isolation is improved, but coal resource loss and spontaneous combustion risk increase
Solution Approach 1:
The method extracts and eliminates the need for pillar retention by using the inclination of the coal seam to create self-isolating mining faces. Each mining face is separated by elevation rather than by physical pillars, removing the source of spontaneous combustion while maintaining safety isolation.
Solution Approach 2:
Instead of retaining pillars to create isolation between mining areas, the method inverts the approach by using elevation differences to create natural isolation. The mining faces are arranged such that gravity and ventilation flow naturally separate the mining zones without requiring artificial pillar barriers.
4Productivity
If downward inclined mining is used, then coal transport efficiency is improved, but gas accumulation and air pollution issues arise
Solution Approach 1:
The mining method dynamically switches between downward inclined mining and upward topple mining based on the specific mining face and coal seam conditions. This dynamic approach allows the system to adapt to different geological conditions while maintaining both transport efficiency and gas venting capabilities.
Solution Approach 2:
The mining operation uses periodic alternation between downward inclined mining and upward topple mining cycles. This periodic action ensures that gas accumulation is prevented by alternating the direction of mining, while maintaining the efficiency benefits of inclined mining throughout the operation.
Data Source
AI summary
A method is to excavate main roadways in the upper and lower parts separately and an inclined intake roadway in the central part of the mine and pre-excavate an inclined seam roadway as the first mining face at the boundary on one side of the mine. Staring from the mine boundary, the retreating mining shall be carried out on the first mining face strip by strip with belt conveyors arranged in the upper main roadway and assistant conveying devices in the lower main roadway and inclined intake roadway; the open-off cut of the first mining face shall be built on the underside of the upper main roadway at the boundary of the mine to carry out the downward inclined mining on the strike and along the inclination.