Dendritic Reverse Mining for Thin Coal Seam Recovery

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Solution Overview

Problem

The recovery of unexploited thin coal seams at the end slope of large-scale strip mines is inefficient and poses safety concerns due to lack of effective mining methods, resulting in coal resource waste and disruption to normal production.

Innovation Solution

A dendritic reverse underground mining method involving the development of a main adit and secondary adits, with remotely controlled continuous mining equipment and self-moving belt conveyors, allowing for coal extraction and simultaneous filling to ensure stability and safety, while minimizing disruption to ongoing operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If traditional mining methods are used for thin coal seams at end slope, then mining can be conducted, but the mining efficiency is low and production is disrupted

Engineering Contradiction:

Improvemining efficiencyVSAvoidmining cycle duration

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The patent applies reverse mining by excavating from the end slope boundary toward the interior, opposite to traditional forward mining approaches. This inversion enables efficient recovery of thin coal seams (0.8-3.5m thick) at the end slope while maintaining production continuity through systematic dendritic adit development and sequential mining sequences

Inventive Principle:

Principle #13The other way round (Inversion)

2Ease of manufacture

If mining equipment is deployed in traditional configurations, then coal extraction is possible, but equipment relocation is difficult and construction complexity increases

Engineering Contradiction:

Improveconstruction easeVSAvoidmining system complexity

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The mining system is segmented into multiple functional components: dendritic adits for access, mobile continuous miners for extraction, self-moving conveyors for transport, and remote control systems. This segmentation allows flexible deployment and relocation of equipment through the adit network, reducing construction complexity while maintaining operational efficiency

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs mobile and self-moving equipment including continuous miners that can relocate along adits and self-moving belt conveyors that automatically position themselves. This dynamic capability simplifies equipment relocation and reduces the need for complex fixed installations, directly addressing construction ease while managing system complexity

Inventive Principle:

Principle #15Dynamics

3Reliability

If conventional mining approaches are used, then coal recovery is achieved, but safety risks increase and stability is compromised

Engineering Contradiction:

Improvemining safetyVSAvoidmining area stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent implements preliminary support measures including roof bolting, shotcreting, and pillar preservation before and during mining operations. These preliminary actions stabilize the mining area and ensure safety by preventing roof collapses and ground control issues before they can affect production

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The dendritic adit system serves as an intermediary structure that provides safe access and egress routes while maintaining stability through proper support. The adits act as mediators between the mining face and the surface, allowing controlled extraction while preserving ground control and safety through their structured development pattern

Inventive Principle:

Principle #24Intermediary (Mediator)

4Quantity of substance

If thin coal seams at end slope are mined using traditional methods, then some coal is recovered, but resource waste occurs and production is affected

Engineering Contradiction:

Improvecoal recovery quantityVSAvoidoverall mining productivity

Core Design Contradiction:

Quantity of substanceVSProductivity

Solution Approach 1:

The dendritic adit system serves multiple functions: providing access for mining equipment, serving as transport corridors for coal removal, enabling ventilation, and facilitating drainage. This multi-functionality allows efficient recovery of thin coal seams without disrupting overall mining productivity, as the same infrastructure supports multiple operational requirements simultaneously

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS11994027B2Dendritic reverse underground mining method for thin coal seam at end slope of strip mine

Publication Date: 2024.05.28 CHINA UNIV OF MINING & TECH

AI summary

The present invention discloses a dendritic reverse underground mining method for a thin coal seam at an end slope of a strip mine. The method includes the following steps: step S1: using a continuous coal mining machine to excavate a main adit toward a boundary of the strip mine along a seam floor; step S2: excavating secondary adits on two sides of the main adit obliquely in a forward direction of the main adit; step S3: transporting the excavated coal out of the main adit by the self-moving belt conveyors; step S4: after the excavating of a secondary adit of the secondary adits is ended, withdrawing the continuous coal mining machine and the self-moving belt conveyor from the secondary adit, and then excavating subsequent secondary adits of the secondary adits in a similar way; step S5: filling the secondary adits, and filling a goaf of the main adit.