Mine Site Greenhouse Gas Mitigation

Australian Decommissioned Mines Gas Prediction

Mine Site Greenhouse Gas Mitigation » Mine Site Greenhouse Gas Mitigation

Published: September 06Project Number: C14080

Get ReportAuthor: Les Lunarzewski, David Creedy | Lunagas, Wardell Armstrong

A previous ACARP project C13007 Gas Emission Curves For Sealed Goaves Or Abandoned Mines established gas emission decay curves for dry coal mines. The gas emission characteristics following cessation of coal production fall into three categories:

  • Production gas rapid decline phase
  • Background gas stabilisation phase, and
  • Background gas long term decline phase.

Background gas is the emission from worked out areas and mature goaves.  Production gas is the release of gas from sources freshly disturbed by mining activity. During mining both production and background gas is emitted but about three months after coal production ceases, the latter becomes the dominant process. By the time 12 months have elapsed the long term decline phase is usually established and background gas flow can be represented by an exponential of the form

where ‘x’ is time, ‘a’ is initial emission and ‘b’, a decay constant.

This project is a continuation which updates the formulae (curves) for the dry mine case and extends the prediction process to take account of groundwater recovery which occurs when a mine is closed and water pumping is halted. The research shows that in Australian conditions, when estimating the total decommissioned mine methane, account should be taken of the gas remaining in both the coal seams and the strata disturbed by longwall extraction, plus gas remaining in coal pillars where there has been extensive room­ and­ pillar extraction. As the workings flood, gas sources are progressively isolated and gas flows decay more rapidly than with the dry situation.

The effect of flooding is to progressively remove gas sources and this process can be simulated using the “Wetsim” decay prediction method by setting emissions from progressively shallower longwall goaf areas to zero as water level rises. The time taken for the workings to flood is calculated using a void model and inferred water inflow data. Two simple, empirical methods for rapidly assessing flooding effects on gas emission have also been developed.

The integral of an emission decay curve provides a first order estimate of potentially accessible DMM resource. The magnitudes of the individual gas source components can be back calculated using a geological resource model and the extraneous strata gas found by difference. The original total quantities of gas ­ in ­place (GIP) before mining can also be estimated; for the two study mine sites these are substantially greater than previously thought which may have implications for gas emission prediction models applied to working coal mines. Thus, a methodology has been established for assessing greenhouse gas emissions from closed mines and estimating methane availability for utilisation for dry and flooding scenarios.

A package encapsulating all the key data will be supplied to ACARP to be used for future research subject to the written approval of the data owners.

The accuracy of DMM predictions depend largely on the quality and quantity of data available. Determined efforts are needed to gather relevant data during the mine closure process when key staff members are being reassigned and priorities have been refocused on the next mining project.


Health and safety, productivity and environment initiatives.

Recently Completed Projects

C26047Real Time Dust Monitor

The aim of this project was to develop a real time respirable dust m...

C29034Integrated Roadway Development: A Strategic Industry Review

This report describes the outcomes of a strategic review of Australi...

C26062New Outburst Risk Determination Measures Along With Data Gathering And Analysis For Coal Burst Assessment

Bursts are events that expel material at velocity at the time of eje...


Open Cut

Safety, productivity and the right to operate are priorities for open cut mine research.

Recently Completed Projects

C27009Tailings Revegetation Project Through “The Vegetative Water Pump”

This project aimed to greatly reduce the water trapped below the cru...

C29043Design, Construction And Commissioning Of Tyre Handler Test Apparatus

C29030Mapping Of Elemental Coal Content For Exploration And Mining

This project has analysed the concentrations of 50 elements not typi...

Open Cut

Coal Preparation

Maximising throughput and yield while minimising costs and emissions.

Recently Completed Projects

C26010Multi-Sloped Screening Efficiency With Changing Strokes, Frequencies, Feed Solids And Feed Rates-Pilot Plant Study

Optimising multi-sloped screens is often described as an art and the...

C28059Impact Of Water Quality In Coal Handling And Preparations Plants

The objective of this project was to deliver a concise reference do...

C27026Ultra-Low Ash Coal By 3D Binder Flotation

The objective of this project was to investigate the potential to pr...

Coal Preparation

Technical Market Support

Market acceptance and emphasising the advantages of Australian coals.

Recently Completed Projects

C28067Characterisation Of Complex Coal Blends, And Methodology To Investigate Thermal Coals Based On Compositional Analysis

This project built on the outcomes from project C25049 (Fusibility ...

C28066Influence Of Coal Blending On Coke Nanoporosity And CO2 Reactivity

Reactivity of coke is one of the most important parameters that defi...

C29077The Effects Of Ash Minerals On Coke Reactivity At High Temperatures

An investigation into how coke mineralogy affects coke reactivity ha...

Technical Market Support

Mine Site Greenhouse Gas Mitigation

Mitigating greenhouse gas emissions from the production of coal.

Recently Completed Projects

C23052Novel Stone Dust Looping Process For Ventilation Air Methane Abatement

This multi‐phase project is concerned with the mitigation of m...

C27054Optimisation Of A Thermal Flow Reversal Reactor For Ventilation Air Methane Mitigation

Ventilation air methane (VAM) generally accounts for 50-85% of the t...

C28076Selective Absorption Of Methane By Ionic Liquids (SAMIL) - Phase 2 Demonstration In A Packed Bed Reactor

An alternative approach to high temperature oxidation of ventilation...

Mine Site Greenhouse Gas Mitigation

Low Emission Coal Use

Step-change technologies aimed at reducing greenhouse gas emissions.

Recently Completed Projects

C17060BGasification Of Australian Coals

Four Australian coals were trialled in the Siemens 5 MWth pilot scale ga...

C17060AOxyfuel Technology For Carbon Capture And Storage Critical Clean Coal Technology - Interim Support

The status of oxy-fuel technology for first-generation plant is indicate...

C18007Review Of Underground Coal Gasification

This report consists of a broad review of underground coal gasification,...

Low Emission Coal Use

Mining And The Community

The relationship between mines and the local community.

Recently Completed Projects

C16027Assessing Housing And Labour Market Impacts Of Mining Developments In Bowen Basin Communities

The focus of this ACARP-funded project has been to identify a number...

C22029Understanding And Managing Cumulative Impacts Of Coal Mining And Other Land Uses In Regions With Diversified Economies

The coal industry operates in the context of competing land-uses that sh...

C23016Approval And Planning Assessment Of Black Coal Mines In NSW And Qld: A Review Of Economic Assessment Techniques

This reports on issues surrounding economic assessment and analysis ...

Mining And The Community


National Energy Research,Development & Demonstration Council (NERDDC) reports - pre 1992.

Recently Completed Projects

1609-C1609Self Heating of Spoil Piles from Open Cut Coal Mines

Self Heating of Spoil Piles from Open Cut Coal Mines

1301-C1301Stress Control Methods for Optimised Development...

Stress Control Methods for Optimised Development and Extraction Operations

0033-C1356Commissioned Report: Australian Thermal Coals...

Commissioned Report: Australian Thermal Coals - An Industry Handbook