Underground

Evaluation of In-Seam Borehole Stability in Coal Mines

This report presents an analysis of techniques used in Australian and overseas mines to stabilise gas drainage holes drilled horizontally in coal seams, with particular reference to the Bulli Seam.   Technologies used for short hole and longhole in-seam drilling in Australia and ....  read more

Development of a General Purpose Hydrogen Sensor

In air, concentrations of hydrogen exceeding 4% are easily ignitable and highly flammable. In coal mines, hydrogen concentrations in the range 1-200 ppm indicate the level of mine "heat up" (spontaneous combustion of the coal face), while hydrogen concentrations at percentage levels ....  read more

Further Development of Remote Control Outburst Mining

This report details advances made and technology trialed when remote mining was undertaken at Tahmoor. Remote mining had previously been demonstrated at Tahmoor as an alternative strategy to counter the significant risk posed by the possibility of outbursts.

In-Seam Drill Monitoring and Bit Location System - Stage 1

This project documents work done during stage 1 of the three stage ACARP project. It is part of an integrated in seam drilling research program supported by the ACA which aims to increase the effectiveness of underground drilling operations.

The project ....  read more

Caliper Probe For Logging In-Seam Boreholes

In response to the great interest in the prediction of outburst zones and detection of geological structures, a caliper logging probe has been developed. The probe is based on the reliable and intrinsically safe ....  read more

Borehole Pressurisation System

This report describes the development, design and surface testing of a device designed to maintain pressure in a borehole during all phases of drilling. This borehole pressurisation device is designed to fit  ....  read more

Development of a Torque Thrust and RPM Sensor

C3073

This report describes the development and design of a drilling substitute (sub) containing torque and thrust sensors for use in rotary drilling or in downhole motor drilling. The sub is a mechanically simple inclusion into a drill string.

In addition to its ....  read more

Standard for In-Seam Drilling Equipment

The aim of this project was to define a common electrical and mechanical specification for the manufacture and deployment of sensor equipment that may be used behind the motor in inseam drilling. The goal was to facilitate the testing and use of new sondes. The need ....  read more

Real Time Return Gas Monitoring for Outburst and Gas Drainage Assessment

The aim of this project was to create a turn key, prototype, stand alone, real time, gas monitoring system capable of providing quantitative assessments of gassiness levels on at least a shift by shift basis and enabling unusual gas emission patterns to be readily flagged. The project involved ....  read more

Gas Detection Technique and Equipment to Continuously Monitor Gas in Drill Fluid

A fluid logging system for underground drilling can be used as a complementary method for the recognition of gas and gas-rock outburst prone conditions ahead of the face and along an inseam drill hole.   Mud logging technology has been used in surface boreholes in the oil industry, ....  read more

Symposium on Management and Control of High Gas Emissions and Outbursts in Underground Coal Mines

This conference was held from 20-24 March 1995 at Wollongong. It was attended by 220 delegates from 14 countries, and advanced the mining industry's understanding of the causes and prediction of gas induced outbursting in coal mines.

Stimulation of Gas Make from Horizontal In-Seam Drain Holes by Hydraulic Fracturing

Hydraulic fracturing was attempted as a way of stimulating horizontal gas drainage holes in coal at German Creek Mine, Central Colliery. Work was carried out in one horizontal hole  ....  read more

Sudden Outbursts of Gas and Coal in Underground Coal Mines

The phenomenon of outbursts of gas, coal and rock is neither new nor isolated in its occurrence to a particular coal field. It has occurred in virtually all the major coal producing countries of the world.  In the last 150 years, as many as 30,000 outbursts have occurred in the world, ....  read more

Coordination of In-Seam Drilling Research

In-seam drilling was recognised as the top priority for underground coal exploration research at the ACA Workshop "Underground Coal Mining Exploration Techniques" culminating in the ACARP funded In-seam Drilling Research Scoping Study completed in 1993. The Scoping Study defined the ....  read more

In-Seam Drill Monitoring and Bit Location System (Stage 2)

This report documents the work conducted during Stage 2 of an ACARP project entitled 'In-seam drill monitoring and bit location system'. The project is part of an integrated in-seam drilling research program which aims to increase the effectiveness of underground drilling operations. ....  read more

Sensing and Logging for In-Seam Boreholes

The objectives of this project were to develop sensors for determining the position of the drill bit within the coal seam (roof-floor proximity)  and develop geophysical logging tools for indicating geological conditions within the borehole

  ....  read more

Development of a Hydrogen Monitor for Use In Coal Mines

Transmission of light through a palladium film changes when the film is exposed to and absorbs hydrogen. The changing transmission can be related to the hydrogen concentration and forms the basis for a hydrogen sensor.    To be useful in coal mines, the hydrogen sensor must be ....  read more

Co-Ordination of In-Seam Drilling Research

In-seam drilling technology and priorities for its application have changed considerably since 1993 when the scoping study into in-seam drilling was conducted. Technological advances have mainly been due to the changing attitude in the industry to in-seam drilling and its role in defining ....  read more

Waterjet Assisted Drilling of In-Seam Cross Panel Methane Drainage Holes

For many mines poor development rates for longwall coal blocks are linked closely to problems of underground gas drainage. In an effort to address current safety issues associated with methane drainage and improve longwall productivity, the CMTE has been investigating the applicability of high ....  read more

The Development of a Geosteering Tool for In-Seam Drilling

Geosteering is an oilfield term that refers to directional drilling guidance systems that have on board sensors to determine the rock type either being drilled or in proximity to the drilling head. Geosteering technology allows drills to follow target horizons and return information on the ....  read more

Gas Drainage Flowmeter

This report describes the development of a flow meter for gas drainage operations. It is designed to be inexpensive and to be able to be monitored automatically utilising intrinsically safe electronics.

 ....  read more

Predictions of Outbursts in Underground Coal Mines Based on Radon-222 Anomalies

The frequency and magnitude of instantaneous outbursts increase with depth and rising advance rate. These conditions are increasingly common in coal mining. Effective outburst management strategies will have to respond to this challenge. Unfortunately, most current methods of evaluation ....  read more

Investigation of the Potential for Pre-Drainage of the Lower Seams at Appin Colliery Utilising Hydra

This report examines the potential for enhancing gas drainage performance from the lower coal seams of the Illawarra coal measures by utilising hydraulic fracturing in cross measure holes to stimulate gas production.  The relative impacts of drainage hole spacing and drainage time are ....  read more

Degassing of Methane and Carbon Dioxide: Prediction of Gas Composition

Coals at depths greater than 200 to 400m usually contain significant quantities of gas, which is predominantly methane (CH4 ). However, many coals contain large amounts of carbon dioxide (CO2 ) and mixtures of CH4 and CO2. Safe underground coal mining requires management of these gases, ....  read more

Automatic Valve for Immediate Shut-Down of Gas Capture from Underground Sources

Underground gassy coal mines both throughout the world and in Australia, often experience periods of high gas emission or weekend-holiday breakdowns, in which the best option is to shut down production, clear out the area and wait for the gas to subside, resulting in costly delays and ....  read more

Borehole Shut Off Valve for Gas Drainage Systems

This report describes the development and form of a shut off valve designed for gas drainage systems in underground coal mines. The valve is designed to close off flow from boreholes in the event of damage to the gas drainage pipeline.

The shut off valve developed is designed ....  read more

Factors Influencing the Accuracy of Measurement of Gas Content of Coal: Intercomparison of the Quick Crush Technique

This project investigated the variability of gas content results across three laboratories processing mine gas content using the new quick crushing or fast desorption method.

In this study some 10 horizontal boreholes were drilled into coal seams from newly developed roadways ....  read more

Outburst Mechanisms: Coupled Fluid Flow-Geomechanical Modelling of Mine Development

Outburst risk management

A gas outburst is an essentially dynamic event in which coal and/or rock is projected into a mine opening, accompanied by a rapid release of gas. In Australian experience, the mass of coal/rock may range from small (less than 1 t) to very ....  read more

Precursors and New Understanding of High Gas Emissions at Appin Colliery Through Microseismic Monitoring

During part of 1996, a microseismic monitoring program was carried out at Appin Colliery to investigate the geomechanical behaviour associated with longwall mining. The data obtained in that study also provided the opportunity to investigate any seismic signatures associated with gas ....  read more

Borehole Dielectric Probe for the Detection of Mylonite Zones and Other Structures

The measurement of the high-frequency electrical properties of the materials surrounding a borehole can provide a means of logging changes in seam material and structure with distance along a hole and can possibly also give some positional information on roof and floor.

The electrical ....  read more

Co-Ordination of In-Seam Drilling Research

In-seam drilling technology and priorities for its application have changed considerably since 1993 when the scoping study into in-seam drilling was conducted. Technological advances have mainly been due to the changing attitude in the industry to in-seam drilling and its role in ....  read more

Longhole Waterjet Rotary Drilling for In-Seam Gas Drainage

Gas drainage is a major issue currently affecting underground coal mines. The difficulties associated with underground gas drainage are partly responsible for the poor development rates for longwall coal blocks; this in turn limits coal production from underground operations. In an ....  read more

In-Seam Drill Monitoring (Stage 3)

This report documents the work conducted during Stage 3 of an ACARP project entitled ‘In-seam Drill Monitoring’. This project is part of an integrated in-seam drilling research program that aims to increase the effectiveness of underground drilling operations. BHP has conducted ....  read more

Maximising Coal Production in the Presence of H2S Seam Gas

The study addresses Hydrogen Sulphide (H2S) in coal seams. The objectives of the project were to undertake a comprehensive series of interrelated studies to gain a full understanding of this complex problem. The goal was to understand how, where and why high concentration zones of H2S ....  read more

The Barclay Mowlem Mine Ventilation Systems

The test programme of 4 consecutive blasts and 1 further `inadvertent' blast, conclusively demonstrated that the overcast design can successfully withstand the target rating of 5 psi.  The level of blast intensity applied, the deformation response of the structure and the basic ....  read more

Co-ordination of In-Seam Drilling Research

In-seam drilling technology and priorities for its application have changed considerably since 1993 when the scoping study into in-seam drilling was conducted. Technological advances have mainly been due to the changing attitude in the industry to in-seam drilling and its role in ....  read more

Demonstration of Bit Torque, Load, RPM and Survey Tool

Geosteering is an oilfield term that refers to directional drilling guidance systems that have on board sensors to determine the rock type either being drilled or in proximity to the drilling head. Geosteering technology allows drills to follow target horizons and return information on the ....  read more

High Speed Cross Panel Drilling

Gas drainage is a major issue currently affecting underground coal mines. The difficulties associated with underground gas drainage are partly responsible for the poor development rates for longwall coal blocks; these in turn limit coal production from underground operations. In an ....  read more

Displacement of Methane from the Goaf into the Working Place as a Result of Wind Blasts in Underground Coal Mines

The potential expulsion of methane from the goaf during wind blasts and its possible incursion into the working place has been of concern to the Australian underground coal mining industry for many years. For example, the explosions at Moura No. 4 Mine in Queensland in 1986 and at Endeavour ....  read more

Commercialised Version of Automatic Shut Down Valve

Underground gassy coal mines both throughout the world and in Australia, often experience periods of high gas emission or weekend-holiday breakdowns, in which the best option is to shut-down production, clear out the area and wait for the gas to subside, resulting in costly delays and ....  read more

Coordination of In-Seam Drilling and Gas Research

The objectives of this project were:

• To maintain communications amongst all inseam drilling and gas personnel
• To assist coordination of all research and development efforts in in-seam drilling and outbursts,
• To assure the knowledge gained from previous

Evaluation of a Full Scale Pressure Test for Ventilation Control Devices

This report describes recent research undertaken to develop, evaluate and calibrate a full-scale pressure test facility for ventilation control devices (VCDs) within Australia. It also examines a number of important aspects of stopping and seal performance, usage, design and application for the ....  read more

Technology and Feasibility of Potential Underground Thick Seam Mining Methods

In Australia there are over 17 Billion tonnes of resources of thick coal seams applicable to extraction by underground methods. There have been a number of research investigations over the past twenty years to investigate safe and efficient means of extracting these resources. However the ....  read more

Data Handling for Gas Drainage Flowmeters (FREE VIA EMAIL)

This report describes the development and final form of an electronic system designed to monitor underground gas flowmeters. The system is designed to power and communicate with up to 255 devices along a twisted pair cable which may have a length of up to 2 km. The flowmeters may be replaced ....  read more

High Speed Cross Panel Drilling System

Gas drainage is a major issue currently affecting underground coal mines. The difficulties associated with underground gas drainage are partly responsible for poor development rates for longwall coal blocks; this in turn limits coal production from underground operations. In an effort to ....  read more

Reproducibility of Gas Content Measurements Using the Fast Desorption Technique

Gas content measurement is a principal tool for the assessment and management of outburst risk by the Australian underground coal industry. Most gassy underground mines use a gas content threshold as a major determinant as to whether mining is permitted to take place. Gas content measurement ....  read more

Dust Measurement and Control in Thick Seam Mining

The scoping study examined dust problems that are being faced by thick seam longwall mine operators, evaluated options and recommend priorities for improvement. The increasing scale of thick seam longwalls challenges the maintenance of safe and healthy face environments in Australian ....  read more

Longhole Water-Jet Drilling for Gas Drainage

In-seam drilling for gas drainage is now an essential part of operations at many Australian underground coalmines. Gas drainage is required to reduce inseam gas content to below threshold levels for safe roadway development and panel extraction. Failure to drain coal increases the risk of ....  read more

The Application of Infra-Red ‘Open Path’ Methane Detection and Measurement to Australian Underground Coal Mines

Infra-red 'open path' methane detection and measurement has been widely adopted by the oil, gas and petrochemical industries. Such systems determine in-situ methane concentration over a path between two points where the path length may vary from 500 mm to more than 200 metres. Coal industry ....  read more

Numerical Modelling of Outburst Mechanisms and the Role of Mixed Gas Desorption

This project is an extension of Project C6024 (Wold and Choi, 1999). The project aims to develop a high level numerical model for the simulation of coal and gas outbursts, for the purposes of:

• improved application of outburst risk criteria under variable mining conditions

Improved Application of Gas Reservoir Parameters

The project is centred on improving the understanding and accuracy of gas reservoir modelling applied to coal mining. It covers a description and evaluation of the input parameters, primarily gas content, permeability, relative permeability, gas sorption capacity, desorption ....  read more

Gas Drainage Efficiency Improvement

Access to underground coal reserves in Australia and other coal producing countries is often conditional on the reduction of coal gas content to below specified regulatory outburst threshold limits. Reduction of gas content is generally achieved by pre-drainage of the coal seam using ....  read more

Develop In-Situ Test Methods for Ventilation Structures - Phase 1

This project set out to determine the feasibility of using non-destructive testing methods to evaluate the strength of ventilation control devices to withstand the required ....  read more

Drilling Technologies for Soft & Low Permeability Coals

This project was designed to address two specific and separate issues affecting underground inseam drilling; soft coal and tight (low permeability) coal. These two separate problems have a common tangible consequence; difficulty in draining gas to threshold levels to enable mining to proceed ....  read more

Optimisation of Longwall Goaf Gas Drainage & Control Systems

The main objective of the project was to develop and demonstrate optimum goaf gas drainage and control strategies for improved gas management in longwall panels in order to reduce gas delays on the face. The project has combined extensive field studies together with computational fluid ....  read more

3D Permeability Characterisation of Large Coal Samples

ACARP, Newlands and Kestrel have supported a University of Queensland project investigating the 3-dimensional permeability characteristics of coal under true triaxial stress conditions. This is achieved by using the world-first True Triaxial Stress Coal Permeameter (TTSCP), ....  read more

Variability of Coal Seam Parameters for Improved Risk Assessment for Gas Outburst in Coal Mines

The project was undertaken by CSIRO Petroleum with the broad objective of improving the basis for gas outburst risk assessment.  The roles of coal permeability and strength in gas outburst mechanisms were investigated with particular reference to their spatial variability on a  ....  read more

Gas Drainability and Outburst Risk Assessment based on the Distribution of Micro-Markers in Coal Seams

Access to underground coal reserves in Australia and other coal producing countries is often conditional on the reduction of coal gas content to below specified regulatory outburst threshold limits. Reduction of gas content is generally achieved by pre-drainage of the coal seam using ....  read more

Optimising Sand-Propped Hydraulic Fracture Stimulation of In-Seam Gas Drainage Holes

Dartbrook coal mine sponsored a trial of sand-propped hydraulic fracturing as a way of stimulating gas drainage rates from in-seam horizontal gas drainage boreholes. The trial placed 20 propped fractures in a borehole drilled from 10 cut through and 10 fractures in a second borehole ....  read more

Gas Emission Curves for Sealed Goafs or Abandoned Mines

Lunagas was asked to perform a professional data and results analysis regarding gas emission phenomenon for sealed goaves and abandoned coal mines in Australia. Consequently, historical data and results for the period 1985 - 2004 were used to establish the most typical curves, which  ....  read more

Remote Methane Measurement in Underground Coal Mines

No gas sensor currently employed in underground coal mines is capable of remote sensing. Such a device would be of considerable benefit to the Australian coal mining industry in that it would facilitate methane detection and measurement in difficult-to-access locations.

The ....  read more

Laboratory Study Of Coal Properties & Outburst Simulation - Application To Gas Drainage, Outburst Prediction, Control & Management

This project is an extension of work conducted in Project C6024 (Wold and Choi, 1999) and C9023 (Choi and Wold, 2003). Some of the results from Project C11030 (Wold et al., 2006) were also utilised in this project. The aims of the research project were to:

· Improve the ....  read more

Implications of Production Scale Hydraulic Fracturing by Coal Bed Methane Drainage Operations on the Subsequent Safe and Efficient Mineability of Coal Seams

Production scale hydraulic fracturing is routinely used by petroleum operators to stimulate water and gas production in coal bed methane projects.  Where petroleum leases overlap with current or future coal mining leases, production scale hydraulic fracturing has been identified by ....  read more

Development of a Web-Based, Underground Coalmine Gas Outburst Information Management System

In February 2002 a survey result was presented at a workshop in Wollongong on ACARP Outburst Research Needs. The workshopconfirmed a strong desire by the coal industry to establish an Internet-based information management system, a gateway, on outbursts of gas and coal in ....  read more

Coal Mine Outburst Mechanism, Thresholds and Prediction Techniques

This report should be compulsory reading for those responsible for mining coal with significant gas content.

This report has been prepared as a document which describes outbursts and their mechanism in an environment where most Australian Coal miners have never seen an  ....  read more

Borehole Permeability Damage and Its Impacts on Gas Drainage

Drainage of gassy coal seams using boreholes is essential to many coal mining operations. The effectiveness with which boreholes drain the coal gas is a complex function of seam and borehole properties. A complication to the drainage process occurs when the fluid permeability is lowered in the ....  read more

Foam Injection Technologies for Goaf Inertisation

This report consists of the summary of the research work carried out under the Australian coal association research program (ACARP) project C15020 -"Foam Injection technologies for Goaf Inertisation". The main objective of the project is to develop and demonstrate the application of ....  read more

Review of Inseam Drilling Practice

It has long been recognised that current inseam drilling practice in Australia has serious limitations and likely results in higher than necessary costs to mining operations.  Failed boreholes due to "boggy ground" and poorly performing individual borehole drainage are a common ....  read more

The Effects of Water Within the Coal Matrix on Gas Drainage

Gas drainage from coal is a complex process whereby gas, initially adsorbed within the coal matrix, becomes a free phase and migrates through the matrix into the cleat system and eventually into a drainage borehole. The effect of water in the cleat system on the gas migration process is well ....  read more

Validation and Application of a Numerical Outburst Model as a Tool for Outburst Management Through Field Studies

1. The basic underlying mechanism for outburst initiation involves the expulsion of coal at a pressure gradient above a critical value which is directly related to the strength and porosity of the coal at the current state. Coal strength, porosity, stress, gas pressure and pressure gradient are ....  read more

Likelihood of High Overpressures on Seals

The US Sago mine disaster in 2006 caused mine seals to be destroyed by an atmospheric explosion. Investigations into the appropriateness of seal strength requirements to withstand a pressure event followed. New designs have been developed and various US changes implemented.  Australian ....  read more

Phase II - Tools to simplify the Coiled Tube Drilling System and Phase I - Coiled Tubing Drilling System Development - Risk Mitigation

This project is a continuation of ACARP project C17017 "Phase I - Coiled Tube Drilling System Development - Risk Mitigation".  The Phase I project developed a concept and performance specification for an underground in-seam coiled tube drilling rig. It also addressed a range of ....  read more

Factors Affecting The Drainage Of Gas From Coal And Methods To Improve Drainage Effectiveness

The relationship between gas production from underground-to-inseam (UIS) drainage boreholes and various coal seam properties and operational factors were examined. Gas production from 279 UIS gas drainage boreholes was collated and assessed relative to a variety of coal geological properties ....  read more

Assessing Measurement Procedures for Estimating Greenhouse Gas Emissions from Underground Coal Mining

With the introduction of the National Greenhouse and Energy Reporting Act 2007, underground coal mines are now required to report their annual fugitive greenhouse emissions to the Department of Climate Change. Emission estimates are to be made in accordance with the prescribed methods of the ....  read more

The Green Book - Spontaneous Combustion in Australian Coal Mines

This reference text called 'The Green Book', was prepared by Simtars in 1996 in response to a need for reference material on spontaneous combustion which relates to Australian coal mining practices and conditions.

This new edition reflects the significant ....  read more

Development of an Alternative Electronic Spark Test Apparatus

In this phase of the project, CRCMining has further developed and demonstrated proof of concept for an electronic alternative to the Spark Test Apparatus (STA) currently used in intrinsic safety (IS) certification of power supplies for use in an explosive environment. The Electronic Spark ....  read more

The Geophysical Estimation Of Concentration and Composition of Gas In-place In Un-mined Coal Seams

The primary objective of this project was to demonstrate an ability to predict concentration and composition of Gas In Place (GIP) from a deterministic analysis of geophysical logs and laboratory measurements on core samples. We have achieved this goal in respect to the determination of gas ....  read more

An Innovative Fibre Optic Based Methane Sensor

The release of methane gas into underground coal mines is an unavoidable consequence of most coal mining operations. The presence of such gas in mine environment poses some safety and health concerns and requires constant monitoring by means of an intrinsically safe, fast, reliable and ....  read more

Controlling Heatings and Gas Leakage Using Innovative Polymer Gel - Pilot Scale Testing

The primary objective of this project was to carry out pilot scale tests of gel systems developed in ACARP project C14021 for assessing the effectiveness of the control of simulated pillar and roof fires.

In this project, the following major tasks have been completed:

Measurement and Reporting of Fugitive Emissions from Underground Coal Mines

The National Greenhouse and Energy Reporting Act 2007 (Act), the National Greenhouse and Energy Reporting Regulations 2008 (Regulations) made under that Act and the National Greenhouse and Energy Reporting (Measurement) Determination 2008 (No.1) (the Determination) ....  read more

Improved Efficiency of Gas Capture from Boreholes Under Active Longwall Panels

Mines can be affected by seams with a high gas content underlying the target mining horizon. Additional gas can be liberated from these seams during longwall extraction making it difficult to maintain an efficient drainage program. If the permeability of the lower seams is low, then ....  read more

Outburst Risk Determination and Associated Factors

This report covers an investigation into the factors that lead to an outburst. It also covers the processes of measurement to arrive at the quantification of these and the shortcomings thereof. As part of the study a large number of outburst cases have been examined. This data base has come ....  read more

High Speed In-seam Drilling System for Effective Gas Drainage

A continuous feed, high speed drilling system for underground gas drainage promises to transform productivity of underground coal gas drainage drilling. CRCMining has been developing continuous waterjet drilling technology for over two decades. Recent commercialization of the surface to inseam ....  read more

Field Trials of Nitrogen Injection Into UIS Directional Boreholes to Enhance Gas Drainage in Low Permeable Seams

Pre-gas drainage is widely used as an effective method to control gas and coal outburst in underground coal mines. However difficulties of reducing gas content below threshold limit values (TLV) within a given drainage lead time have been encountered in some coal mines in QLD and NSW, ....  read more

Drilling for Outburst Risk Determination

This project's purpose was to determine parameters that may be indicative of outbursting from normal gas drainage drilling using down hole motors. The objectives were to measure, on a sample by sample basis, gas content and diffusion coefficient of the coal being drilled. It was also ....  read more

Ventilation and Gas Management - Underground Coal Mines

This planning guideline has been prepared to assist mine operators to apply a best practice approach to ventilation and gas drainage planning. It has been prepared on the basis that there is room for improvement and more consistency in the process of developing and maintaining ventilation ....  read more

Specific Gas Emission Patterns from Different Coal Seams

Gas emission prediction plays a critical role in mine ventilation and gas drainage planning and design, to meet coal production targets and safety standards. Gas emission is often expressed in the form of specific gas emission (SGE, unit: m3/t), which refers to the volume of gas emitted per ....  read more

Gas Management and Risk Mitigation Strategies for Longwalls

The main objective of this project was to develop optimum goaf gas management and risk mitigation strategies for highly gassy longwall mines. The project aimed to obtain a fundamental understanding of the effect of various parameters on goaf gas distribution patterns and investigate the ....  read more

New Approaches to Mine Gas Analysis and Ratios

The spontaneous combustion of coal remains a hazard in underground coal mines. Previous research has indicated that alkanes larger than ethane, propane, volatile organics and aldehydes may be present when coal self-heats. The presence of these compounds in operating underground coal mines in ....  read more

Floor Seam Gas Emission Characterisation and Optimal Drainage Strategies for Longwall Mining

Gas emission from floor coal seams during longwall mining can cause significant safety and productivity issues. It can result in substantial gas make in the ventilation return, exceeding the ventilation system's capacity to dilute the gas to a safe level. Sudden releases of gas into the ....  read more

Control and Management of Outburst Risk

Outburst of coal and gas is a risk that affects many Australian underground coal mines. While the mechanisms that cause an outburst are not fully understood, the factors known to affect outburst risk include seam gas pressure, geology, and stress. Varying combinations of these and other ....  read more

Optimisation of the Coal Seam Gas Predrainage Design Process

This project focused on improving the effectiveness and efficiency of gas predrainage programs to be employed in the underground coal industry. It covered a description of fundamental coal seam and gas reservoir parameters as they relate to coal seam gas predrainage and provides a depiction of ....  read more

Modelling of Strata Gas and Water Transport to the Mining Area

During underground longwall coal mining, roof rocks collapse to fill the mined area as mining progresses. This creates fractures on the strata above the goaf area, which provide flow pathways for the gas and water in the overlying strata to migrate into the mining area. Gas may also migrate to ....  read more

Impact of Gas Composition on Outburst Propensity of Coal

Pre-drainage of coal seam gas is practised in Australian underground coal mines to reduce gas content below the outburst threshold limit values (TLV) to mitigate coal and gas outburst risk. The current TLVs assume that coal containing CO2 seam gas has a significantly higher risk of outburst ....  read more

Impact of Core Sample Recovery Time on Accuracy of Gas Content Measurement

The measurement of coal seam gas content has a significant impact on safety and operational efficiency within Australian underground coal mines. There is an expectation that reported gas content values are accurate and truly represent the gas content of the coal seam in the area from which the ....  read more

Goaf Gas Flow Modelling Using Ventsim: Methods, Tools and Tests

Effective goaf management requires a thorough understanding of goaf gas behaviour under varying conditions such as mine ventilation systems, goaf drainage, inertisation, barometric pressure change and goaf consolidation. However, there is a lack of a practical tool that mine ventilation ....  read more

Development of a Simple Rotary Steerable System for Underground Inseam Drilling

The purpose of this project was to complete the design and testing of a simple rotary steerable system to replace the downhole mud motor systems used in current underground inseam drilling programs. Rotary steerable systems are the state-of-the-art in the oil and gas industry for drilling ....  read more

Revisiting the fast desorption method – Initial gas release from pulverised coal

Gas content measurement in a coal seam is critical to design gas drainage systems and assess mine ventilation requirements, directly affecting coal production rates and thus being required to be measured for outburst management compliance. Gas content is a basis for outburst threshold ....  read more

Appraisal of Gas Indicators from Goaf Drainage Holes for Spontaneous Combustion and Explosion Risk Management

In gassy underground coal mines prone to spontaneous combustion, goaf management is a challenging task to reduce the risks of gas explosion and spontaneous combustion to acceptable levels. Goaf gas drainage via vertical surface goafholes is a primary control method to manage gas emissions in ....  read more

Explosion Risk Exclusion Zones Around Mine Entries In Emergency Situations

The safety of personnel working in coal mines is a crucial concern that necessitates a comprehensive understanding of explosion dynamics, mining operations, and safety protocols. While there is a considerable body of knowledge about gas emissions and gas/coal dust explosions in underground ....  read more

Development of a methodology for efficient design of the pattern of drainage holes based on stress variation and gas flow behaviour in coal seams

Coal seam gas pre-drainage through underground-to-inseam (UIS) horizontal boreholes is one of the common practices for the management of personnel safety and environmental concerns in relation to gas concentration in underground coal mines. In the design of UIS boreholes, local experience is ....  read more

Contamination – Ethylene from Timber Supports

This project investigated the potential, timeframes, and circumstances for timber to produce ethylene in an underground environment. The findings led to the required management of timber supports, to avoid ethylene contamination underground and to increase confidence in mine gas analysis ....  read more

Direct Measurement of the Effective Diffusion Coefficient of Coal

The effective diffusion coefficient of coal is critical in coal mining because it determines the magnitude and likelihood of gas-related dynamic failures such as outburst and, in some cases, coal burst. To assess the risk of failures using previously developed models, an accurate estimation of ....  read more

Reliable Determination of Strata Gas Content Using Geophysical Logs and Laboratory Measurements

The coal mining industry in Australia is facing the ever increasing challenge of managing gas emissions. The coal extraction process in underground mines can significantly alter stress and fracture distributions around mine openings, which forms flow channels for gas emissions into longwall ....  read more

Laboratory Evaluation of Airflow Effects on Coal Self Heating Incubation Behaviour

It is important to understand the influence of mine ventilation on the likelihood of developing of a spontaneous combustion event in a longwall mining environment. To date there has been a general concept proposed for a “critical velocity zone” to exist where conditions are ideal ....  read more

Review longwall face ventilation to mitigate goaf gas emissions onto walkways and tailgate end

As longwall mining increasingly targets deeper coal seams, managing high goaf gas emissions has become a significant challenge, particularly in maintaining effective gas management and ensuring uninterrupted mine production. If not properly controlled, goaf gas can migrate to the longwall ....  read more

VR-CFD Based Simulation Tool for Dust Control in Gateroad Development Panels

Long term exposure to dust particles, in particular respirable dust, continues to present a health and safety hazard to mine workers in underground coal mines. Workers who are exposed to coal dust can develop occupational lung diseases including coal workers' pneumoconiosis (CWP) or ....  read more

Time Lapse In-seam Seismic and Resistivity Measurements as an Integrated Component of a Smart Coal Seam Gas Pre-Drainage Practice – A Literature Review

Coal seam trapped gas in underground coal mines poses significant health and safety hazards for mine personnel and contributes to environmental degradation through greenhouse gas emissions. Underground inseam (UIS) gas pre-drainage is commonly utilised in Australian underground coal mines as a ....  read more