Gob Well Methane Extraction for Trona Mining Safety

Solution Overview

Problem

The mining of non-combustible ores like trona results in the liberation of methane, which poses safety risks due to high concentrations in mine air, requiring extensive ventilation and increased energy consumption to dilute methane levels below explosive ranges, leading to inefficiencies and environmental concerns.

Innovation Solution

A method involving drilling a well above the ore bed to create a gob well that captures released methane from fractured methane-bearing layers, allowing for its recovery and combustion, reducing methane concentration in mine air and providing a valuable energy source.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If extensive ventilation is used to dilute methane levels below explosive ranges, then safety is improved, but energy consumption increases

Engineering Contradiction:

ImprovesafetyVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent extracts methane gas from the mined-out cavity (gob) using dedicated withdrawal boreholes before it can mix with mine air and reach explosive concentrations. This prevents the need for extensive ventilation dilution, thereby improving safety while reducing energy consumption for ventilation systems.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent converts the harmful methane gas into a beneficial energy source by withdrawing it and combusting it in engines or turbines to generate electricity. This not only eliminates the safety hazard but also produces useful energy, addressing both safety concerns and energy consumption issues.

Inventive Principle:

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

2Use of energy by moving object

If methane is allowed to accumulate in mined-out areas, then ventilation requirements are reduced, but safety risks increase due to high concentrations

Engineering Contradiction:

Improveventilation requirementsVSAvoidsafety risks

Core Design Contradiction:

Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent extracts methane gas from the mined-out cavity (gob) using dedicated withdrawal boreholes before it can mix with mine air and reach explosive concentrations. This prevents the need for extensive ventilation dilution, thereby improving safety while reducing energy consumption for ventilation systems.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces an intermediary system (methane withdrawal boreholes and gas management infrastructure) that captures methane directly at the source and transports it to combustion facilities. This intermediary mechanism eliminates the need for methane to accumulate in mined areas, preventing safety risks while reducing ventilation requirements.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Loss of energy

If methane is combusted to generate energy, then a valuable energy source is recovered, but methane concentration in mine air must be carefully controlled

Engineering Contradiction:

Improveenergy recoveryVSAvoidmethane concentration control

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The patent extracts methane gas from the mined-out cavity (gob) using dedicated withdrawal boreholes before it can mix with mine air and reach explosive concentrations. This prevents the need for extensive ventilation dilution, thereby improving safety while reducing energy consumption for ventilation systems.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent implements monitoring systems that continuously track methane concentrations and provide feedback to control the combustion process. This ensures methane is safely combusted to generate energy while maintaining precise control over concentrations, preventing dangerous accumulations and optimizing energy recovery.

Inventive Principle:

Principle #23Feedback

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 approach enhances safety by reducing methane levels in mine air, provides a recoverable energy source for surface refineries, and minimizes greenhouse gas emissions by converting unrecoverable methane into carbon dioxide through combustion.

Implementation Method 1

repeating the mining, advancing and caving steps in a manner effective to cause fracture of the methane-bearing layer and release of mine methane into the gob

Methodology Applied

Scientific EffectFracture: Fracture Mechanics

Implementation Method 2

minimizes greenhouse gas emissions by converting unrecoverable methane into carbon dioxide through combustion

Methodology Applied

Scientific EffectCombustion: Combustion

Data Source

PatentUS8740310B2Mining method for co-extraction of non-combustible ore and mine methane

Publication Date: 2014.06.03 SOLVAY CHEM INC

AI summary

A method for co-extracting non-combustible ore (e.g., trona) and methane from an underground formation comprising at least one methane-bearing layer and a non-combustible ore bed having a rock roof, comprising:providing a well having a downhole end positioned above the ore bed roof;mining an ore region from an initial cavity and removing the mined ore, thereby creating a subsequent cavity;advancing the mining step to another ore region from the subsequent cavity;allowing the roof of the initial cavity to cave so as to create a gob;repeating the mining, advancing and caving steps, the caving being effective in generating fluid communication between the gob and the well downhole end and in fracturing the methane-bearing layer so as to release methane into the gob; andrecovering a gob gas comprising released methane through the well to the surface.