Full Mining Area Coal Extraction Without Pillars

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Solution Overview

Problem

Conventional coal mining methods require extensive excavation, leading to high costs, long preparation times, and safety hazards, while coal-pillar leaving results in resource waste and geological disasters.

Innovation Solution

A coal mining method that drills main, auxiliary, and return air shafts, uses coal mining machines to create haulageways and return airways without excavation, and exploits coal faces in a manner that eliminates coal-pillar leaving and reduces laneway excavation, employing roof-cutting pressure-relieving lane self-formation techniques.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional coal mining methods are used with extensive laneway excavation, then coal production can be achieved, but excavation workload, preparation time, and costs increase significantly

Engineering Contradiction:
Improvecoal production efficiencyVSAvoidpreparation time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent extracts the function of laneway excavation by using the gob space (collapsed coal seam area) as the haulage and return airway. Instead of excavating separate laneways through the coal seam, the method utilizes the naturally formed void space after coal extraction, eliminating the need for preliminary laneway construction and reducing preparation time.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the functions of coal extraction, haulage, and ventilation into a single integrated system. The gob area serves multiple purposes: it is both the extraction zone and the conduit for coal transport and air circulation, eliminating the need for separate laneway structures and reducing overall preparation time.

Inventive Principle:
Principle #5Merging (Combining)

2Productivity

If conventional coal mining methods are used with extensive laneway excavation, then coal production can be achieved, but excavation costs and labor requirements increase

Engineering Contradiction:
Improvecoal production efficiencyVSAvoidexcavation cost
Core Design Contradiction:
ProductivityVSEase of manufacture

Solution Approach 1:

The patent extracts the expensive laneway excavation function and replaces it with utilization of the free gob space. By taking out the need for mechanical laneway excavation through the coal seam and using the naturally collapsed area instead, the method eliminates substantial excavation costs and labor requirements while maintaining coal production capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The gob space self-forms through natural collapse of the roof after coal extraction, providing the haulage and ventilation pathways without requiring additional excavation work. This self-service mechanism eliminates the need for costly preliminary laneway construction and reduces overall manufacturing costs.

Inventive Principle:
Principle #25Self-service

3Reliability

If coal pillars are left between neighboring working faces, then structural support is provided, but coal resource waste occurs and geological hazards increase

Engineering Contradiction:
Improvestructural stabilityVSAvoidcoal resource waste
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent extracts the coal pillars that are traditionally left for structural support and utilizes the entire mining area for coal extraction. By taking out the coal pillars and using the gob space for haulage and ventilation instead, the method eliminates coal resource waste while maintaining structural stability through alternative means.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces the gob space as an intermediary structure that replaces the traditional coal pillar function. The collapsed rock and void space in the gob area provide structural support and stress distribution, serving as a mediator that maintains reliability without requiring coal pillar preservation.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Reliability

If coal pillars are left between neighboring working faces, then structural support is provided, but geological disasters such as rock burst and coal explosion increase

Engineering Contradiction:
Improvestructural stabilityVSAvoidgeological hazards
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the coal pillars that create stress concentration zones and replaces them with gob space. By removing the coal pillars and using the collapsed area for structural support, the method eliminates the harmful stress concentration that leads to rock bursts and coal explosions while maintaining necessary structural stability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent converts the potentially harmful collapsed rock and void space into a beneficial structural support system. The gob space, which could be considered waste material, is transformed into a functional element that provides stress distribution and structural stability without creating the geological hazards associated with coal pillar preservation.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This method reduces excavation workload, shortens preparation times, lowers production costs, prevents safety accidents, conserves coal resources, and mitigates geological hazards by eliminating coal-pillar leaving and laneway excavation.

Implementation Method 1

exploiting by using a coal mining machine cutting a coal wall in a first direction, to form a first mining face with the first direction as an advance direction

Methodology Applied
Scientific EffectMechanical cutting: Mechanical Force

Implementation Method 2

employing roof-cutting pressure-relieving lane self-formation techniques

Methodology Applied
Scientific EffectPressure relief through controlled fracturing: Fracture Mechanics

Data Source

PatentEP3998394B1Method for coal mining without reserving coal pillar and tunneling roadway in whole mining area
Publication Date: 2023.05.10 BEIJING ZHONGKUANG INNOVATION ALLIANCE ENERGY & ENVIRONMENTAL SCI RES INST
  • EP3998394B1 patent drawingFigure 1~2
  • EP3998394B1 patent drawingFigure 3~4
  • EP3998394B1 patent drawingFigure 5

AI summary

The present disclosure discloses a coal mining method without coal-pillar leaving and without laneway excavation in a full mining area. The coal mining method includes the steps of: drilling a main shaft (1), an auxiliary shaft (2) and a return air shaft (3) from a ground to a coal mining layer; by a coal mining machine, forming a first mining face (4) with the first direction as an advance direction; by the coal mining machine, cutting out a first haulageway (5) and a first return airway (6) while cutting the coal wall at the first mining face (4), and preserving the first haulageway (5) and the first return airway (6), wherein the first haulageway (5) and the first return airway (6) are located on two sides of the first mining face (4), the first haulageway (5) is in communication with both of the main shaft (1) and the auxiliary shaft (2), and the first return airway (6) is in communication with the return air shaft (3); and by the coal mining machine, cutting out a second haulageway (10) and a second return airway (11) while cutting a coal wall at the second working face (9), and preserving the second haulageway (10) and the second return airway (11), wherein the second haulageway (10) and the second return airway (11) are located on two sides of the second working face (9). The present disclosure effectively solves the problems in the prior art that coal mining requires a large excavation amount, a long excavation time and a high excavation cost, and the coal-pillar leaving causes waste of the coal resource.