Deanna McMaster, Partner and
Rhian O’Sullivan, Special Counsel, MinterEllison
You may also like
Dr Snezana Bajic
Technical Services Manager, Department of Natural Resources, Mines and Energy (Simtars)
Reliable gas monitoring is a key element to ensure that the mine based controls are effective.
Coal mines in Queensland and New South Wales have been facing issues in controlling tailgate methane levels and recently there have been two serious spontaneous combustion events. Legislation and Australian standards make specific requirements for the installation and maintenance of gas monitoring systems.
This paper discusses the issues related to gas monitoring, tailgate methane control, alarm set points and proposals for feedback loops on alarm notifications and acknowledgements. The paper will not discuss individual mine events but will focus on reliable gas monitoring to enable early detection and proactive actions to be taken.
Professor Jianming Wu
Visiting Professor of University of Wollongong and Director of AST Australia
A/Professor Ting Ren</br/>Director of Centre of Infrastructure Protection and Mining Safety, University of Wollongong
Spontaneous combustion (sponcom) of coal remains a major safety issue for underground coal mining operations. Recent heating incidents in Australia further highlight the need of improving current knowledge and practices of sponcom management to ensure safety and productivity of coal mines extracting coal seams that are prone to spontaneous heating.
This presentation will provide some the fundamental theory and practices in the early detection, prevention and control of spontaneous combustion of coal. Case studies based on Chinese and Australian coal mines will be presented to demonstrate a range of techniques, including radon detection, jel and fly ash injection materials, that can be practically used for coal heating and fire management.
The presentation will also include studies of goaf gas flow dynamics based on computational fluid dynamics (CFD) modelling. Based upon fundamental fluid flow governing equations, computational models are developed to investigate the impact of different ventilation layout and ventilation parameters on goaf gas flow characteristics and in particularly, oxygen leakage and ingress patterns, and hence identification of high sponcom risk zones. Inertisation strategies, using both nitrogen and carbon dioxide, are modelled to optimise operational parameters (e.g, injection flow rate and location etc) for active longwalls and seal-off operations.
Dr Ian Webster – Group Engineering Manager, Ampcontrol Pty Ltd
ABSTRACT
The operation of a diffusion type gas detectors used in fixed, machine mounted and handheld applications is reliant on the natural equalisation of dissimilar gas concentrations driven by partial pressures inside and outside the detector.
Typically, this equalisation is inhibited (to a greater or lesser degree) by protective filters and barriers surrounding the fragile sensing elements from the typically harsh ambient environments. The accumulation of dust and other foreign matter on the protective filters can further inhibit the diffusion of gas into a detector.
The usual calibration process for a gas detector – typically by a ‘bump’ or ‘challenge’ test – will often fail to detect when a detector is blocked, or partially blocked. This can lead to the ‘calibrated’ detector reading high or low, but with no way to determine if that is the case.
Retrospective examination of records and equipment from Pike River Mine lead to the conclusion that critical detectors were affected by filter blockages, resulting in methane detectors reading approximately one-half of the true concentration.
This presentation explores how a blocked detector can give an erroneous reading, and what steps can be taken to avoid replicating previous mistakes.
Nick Coplin – General Manager, Engineering Services, Orbital Australia Pty Ltd
ABSTRACT
Australian Coal Association Research Program (ACARP) project C25073 was proposed by industry stakeholders seeking a solution that would both improve underground air quality and reduce the operational costs associated with currently implemented disposable filter technology used to control diesel particulate emissions in the underground coal mining environment. The follow-on C26070 project sought to industrialise the proof-of-concept (PoC) wall-flow diesel particulate filter (DPF) system to comply with relevant safety and health standards.
The technology has demonstrated significant DPM emissions reduction, comparable to the incumbent disposable technology, and has demonstrated the ability to meet NSW MDG43 requirements for year 2020. Testing noted that whilst the technology increased modal NO2 formation, it was compliant over typical operational duty cycles.
One of the key benefits with the use of a wall-flow DPF system is its tamper-proof design, mitigating the risk of operating unfiltered diesel plant in poorly ventilated areas. Elimination of the need for continual replacement of disposable filters provides significant operational savings estimated to be up to 80% of the incumbent technology.
The robustness of the aftertreatment solution can be maintained with both appropriate design and the use of embedded real-time, and near-real-time, electronic monitoring technology.
Dr Fiona Clarkson – Research Scientist, Simtars
ABSTRACT
Mines routinely monitor the gas profiles in their goafs and roadways to determine the current status of the mine as part of their principle hazard management plan for spontaneous combustion. Many mines typically monitor for hydrogen, oxygen, methane, carbon monoxide, carbon dioxide, ethane and ethylene using micro gas chromatographs.
This paper investigates the existence of other gases which may have the potential to be used to monitor the underground environment for early signs of a heating or developing spontaneous combustion event. Simtars collected goaf and roadway gas samples into Tedlar bags to determine the “normal” background levels of these gases.
The gases analysed for included aliphatic hydrocarbons to C10, Benzene, Toluene, Ethyl Benzene and Xylene (BTEX) and aldehyde compounds. In addition to classical analytical techniques such as Gas Chromatography / Mass Spectroscopy (GC/MS) and High Pressure Liquid Chromatography (HPLC), a new micro gas chromatograph configuration previously developed by Simtars was used to conduct the analysis for aliphatic hydrocarbons to C6 and BTEX.
This paper provides a summary of the extended aliphatic hydrocarbon, BTEX and aldehyde gas profiles found in the longwall goafs and roadways of the surveyed Queensland and New South Wales mines.
Patrick Tyrrell – Australian Coal Industry Research Program
ABSTRACT
ACARP assists the Australian coal industry to develop and adopt technology and mining practice that leads the world. The program is entirely funded, owned and managed by the Australian black coal producers.
ACARP was established in January 1992 and has had many great achievements that improves the safety and health of our people throughout its many years. What sets ACARP apart from other areas of research is the industry monitors that have direct input to the research that is been undertaken through a collaborative approach that utilises the experience and technical strength of both the coal mining industry and research institutions in solving technical problems and addressing issues of significance to the industry’s long-term future. Any proposed research project that is strongly supported by a mine site and is of interest to a number of coal operations is encouraged. Safety and environment remain key drivers in the program and will continue to be the focus of much of the underground work and a significant component of the open cut and coal preparation programs.
Priorities have been developed by the five technical committees responsible for proposal development and selection and are separated into the areas of:
• Underground
• Open Cut
• Coal Preparation
• Technical Market Support
• Mine Site Greenhouse Mitigation
While the current priorities are not prescriptive they should act as a guide.
The Current Priorities are: Underground:
• Prevent Harm from Spontaneous Combustion, Ignitions, Mine Fires, Extreme Heat, Explosions, Outbursts, Coal Bursts, Ventilation and Strata Failures – Improved understanding, detection, prediction, protection, selection and design of major hazard management systems.
• Management of Health – including mental health and fatigue.
• Communication to Employees and Contractors of Safety Measures – Improvement such that the information, training and instruction is understood and retained.
• Operator Interfaces and Vehicle Interaction – Improving equipment, automation and remote monitoring and control, also addressing musculoskeletal disorders, improved ergonomics and
• Improved roadway conditions.
• Airborne and Noise Contaminants – Reduce exposure to airborne dust, diesel emissions, and noise.
• Emergency Response Measures – Adequacy and effectiveness.
• Investigation of key practices, including legislative, leading practice alternatives and culture.
Open Cut: The industry is looking for direct or indirect improvements in health and safety across all mining and exploration operations. Areas of interest for open cut mining are:
• Investigation of key health and safety issues and management systems, practices and culture, including legislative leading practice alternatives.
• Management of health including mental health, alcohol and other drugs, return to work and fatigue, e.g. by reduced exposure to noise, vibration, dust and heat, by determining mental health of employees, etc.
• Protection and removal of personnel from hazardous situations such as those around unstable ground, in the vicinity of voids, and around excavations particularly during truck loading.
• General improvement to the health and safety of mining and maintenance operations through novel manual
• Handling aids, including automated technologies or equipment changes.
• Improving equipment operator interfaces, vehicle interaction management, automation and remote control.
• Development of safety in the design of systems and equipment that leads to the reduction of occupational exposure at the source, e.g. noise, dust, blast fumes etc.
• Improve the communication to employees and contractors of safety measures such that the information,
• Training and instruction are provided in a method that allows cognitive retention.
• Development of a cognitive recognition method which addresses the normalising effects that are created due to the human brain predominantly operating in a subconscious mode and failing to recognise changes in their environment that could lead to adverse outcomes.
ACARP facilitates industry and researchers to work together for a common goal that is the improvement of the health and safety of our industry and our people, this is a journey that we all share together.
André De Kock – Research Manager, Simtars
ABSTRACT
One of the major hazards in an underground coal mine is the interaction between mining equipment and humans. This is the result of limited vision around underground equipment and the confined space within which the equipment operates. To address this hazard, various proximity detection systems have been developed.
This paper describes a project that evaluated three proximity detection systems in an underground coal mine. The systems were subjected to a suite of nine scenarios, involving interaction between humans and continuous miners, shuttle cars and LHDs. In addition, the detection zones of the different proximity detection systems, were determined on surface as well as underground. The underground zones were determined under “normal conditions” (reference pattern), in the vicinity of an underground substation, tags at different heights, and multiple tags in zones.
The scenario results provide a documented comparison of the proximity detection systems performance when subjected to the same scenarios. This will allow a mine to make an informed selection of the most suitable proximity detection system. The detection zone results provide a graphical comparison between the performance of a proximity detection system on surface and underground. The results also present the comparison for “normal conditions” of the proximity detection system and when subjected to EMF radiation, multiple tags and tags at different heights.
The project also identified the need to develop a universal specification for a proximity detection system.
Prof. Robin Burgess-Limerick – Professor of Human Factors, Minerals Industry Safety and Health Centre, The University of Queensland
ABSTRACT
Proximity advisory systems have potential to reduce collision risks associated with surface mining haul-trucks by assisting truck drivers to maintain situation awareness. The design of the visual interface by which information is provided is likely to influence the effectiveness of such systems. During ACARP project C24028, a range of information sources were reviewed including best practice guidelines from other industries. The consequences of different visual interfaces were examined when drivers were presented with potential collision scenarios via a modified haul-truck simulator (Figure 1). Additional information available in a Schematic proximity advisory visual interface was utilised by drivers to reduce collision risk and braking force and decrease travel time; although the effects were smaller in a subsequent experiment involving a smaller number of experienced truck drivers.
Design guidelines have been developed for haul-truck proximity advisory systems. Further work is underway in project C27005 in which a similar experimental paradigm is utilized to examine two of the issues identified as requiring further investigation: the relative benefits of proximity information based on distance only vs collision prediction information; and secondly, the relative benefits of auditory tones vs speech.
Simon Worland – Occupational Hygienist
ABSTRACT
Use of compressed air to blow out or “clean” electrical cabinets is a routine maintenance task across the Queensland Coal Industry. Elevated levels of harmful dust can engulf the blow out operator for extended periods and increase the risk of developing lung diseases including Coal Workers Pneumoconiosis and silicosis.
In 2017 the Queensland Mines Inspectorate reported that approximately 50% of all respirable dust and Respirable Crystalline Silica (RCS) exceedances in surface coal mines was directly related to the use of compressed air for cleaning down enclosures and equipment during maintenance activities.
Respiratory protection has historically been viewed as the primary control to protect the health of blow out operators as dust controls at the engineering level or above have not been considered to be feasible.
Blow out of electrical cabinets on Komatsu 960E haul trucks have been targeted for an engineering dust control project at Hail Creek Mine. The project has focussed on the following areas:
• Sealing of cabinets
• Application of positive pressure
• Local exhaust ventilation / vacuuming
• Identification of alternative cleaning methods
• Measurement of control performance
This paper describes the dust control project along future direction for application of common principles to other equipment such as draglines and excavators.
Fritz Djukic – Inspector of Mines (Occupational Hygiene), Department of Natural Resources, Mines & Energy
ABSTRACT
In May 2015 the first confirmed case of mine dust lung disease (MDLD) in the Queensland Coal industry in over 30 years was reported to the mines inspectorate. A number of cases followed that typically related to underground coal mine workers with extensive exposure history in Queensland, interstate and abroad. In October 2016 the first surface coal mine worker was confirmed with MDLD proving this hazard was not isolated to underground mines. The reidentification of MDLD in Queensland prompted several extensive reviews of the health surveillance system and the respirable dust regulations. This resulted in significant regulatory reforms around exposure monitoring, reporting requirements and the establishment of a central exposure data base.
In January 2018 the Chief Inspector of Coal Mines requested all surface coal operations to provide personal exposure monitoring data collected since the introduction of the risk based legislation. This paper reviews exposure data collected from Queensland surface coal mines and wash plants during the period 2001 – 2017.
Specifically the paper discusses:
• Mean exposure trends across various similar exposure groups for respirable coal dust and respirable
crystalline silica (RCS)
• Personal monitoring programmes and sampling rates
• High dust exposure tasks and single exceedance data
In addition, the study draws comparison with exposure data collected from Queensland coal mines during the eighties (80’s).