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Mobile mining equipment presents only a small portion (ten per cent mining project costs but the selected technology will determine to a large extent the mining performance and mine profitability. The actual performance of the selected mobile equipment technology will rely on the support functions, infrastructure, user interface and user acceptance. Optimising the technology to match the circumstances is an increasingly important phase in a mine feasibility study. Smartly done feasibility studies include the possible future needs of changing or building-up of the selected technology. In massive mining applications the machinery faces quite different challenges than in selective or small-scale mining applications. In massive mining applications the efficient and continuous move of large amounts of material has led to the use of increasing degree of automation. This higher degree of automation in a mining application, on the other hand, will be best applied to a smooth and streamlined mining process and operation. Mining methods like block caving support automated operation. Automated mobile equipment needs supportive infrastructure, monitoring and information transfer systems as well as well established working procedures. Too often the user interface and human factor is disregarded during the consideration of automation. Through the available supplier programming tools it is possible to see how much the selected technology provides flexibility in changing production or economical situations, when major rebuilds or replacements are necessary, and view the effects of all these on the mine economy. When adequate technology is available from various sources, the difference becomes from preparing for the future, managing costs and combining the best layout with the most suitable technological solutions.

Jan 1, 2000

By Quilliam B, Richmond G

Aberfoyle Ltd. has utilised a variety of flotation technologies in the Hellyer concentrator in North-Western Tasmania. Hellyer ore, with its slow flotation rates and low rate differentials between values and gangue, requires the use of long residence times and low air consumption rates in the flotation circuit. The operation of the flotation circuit, with a nominal residence time of 7 hours, has necessitated the development of a control system to provide continuity through operator shift changes. Cell selections at Hellyer varied from the 54 m3 hybrid Dorf Oliver / Maxwell (DO/MX) cells, to smaller 32 m3 Maxwell cells, conventional Don-Oliver 300 (8.5 m3) and 600 (17 m3) trough cells, and a column cell. The advantages of the large cells included low specific power consumptions and a low capital cost. However, problems with mixing and the maintenance of consistent froth depth have been identified in the hybrid DO/MX cells. Short circuiting in the trough cells was apparent, causing a considerable reduction in metallurgical performance. The column cell performs to expectation, although the application is not ideal.

Jan 1, 1991

By J Coombes

Within the mining industry there is a growing trend of placing inexperienced technical people into positions of responsibility beyond their readiness. Their responsibilities often include providing the fundamental basis for decision-making: the resource model or even the daily grade control estimates. Whilst software continues to make the processes more accessible, the thinking and rationale for selecting parameters still requires control rather than auto-piloting. Operators run these systems in virtual isolation, and have limited immediate access to experts. Beyond the stress of the professional burden are the increased risks to the mining operations and overall project success.While many experienced experts recall being thrown in the deep end, the relative isolation from experts coupled with the gravity of professional burden before readiness, is less familiar. Many recall in intimate detail the experts who gave them direction, assisted them along the way and even helped them claw out of inadvertent mistakes. Experienced professionals all have a responsibility to enable capability across the generations, to ease the burden and to mitigate the risks.This paper provides an outline of how mentoring as an on-the-job professional development process can be structured to more fully enable success of a mentoring program. Three examples complement the principles presented.CITATION:Coombes, J, 2012. Structuring meaningful mentoring, in Proceedings International Mine Management 2012, pp 15-22 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 20, 2012

By L P. Gray

"From paving the way in gaining approval for the first metalliferous in-pit tailings storage facility (TSF) in Victoria, to developing a deposition methodology to optimise the storage capacity and provide a final rehabilitated surface which replicates the premining topography, in-pit tailings storage has proven not only to be a cost-effective means for tailings management at Fosterville Gold Mine, but also one which provides significant economic, social and environmental benefits. Coupled with ongoing raising of the existing above ground TSF and commissioning of a new above ground TSF, Fosterville Gold Mine have to date effectively used three open pits for in-pit tailings storage, with one of the pits currently progressing through the capping and vegetation establishment phases of closure.This paper presents the process adopted by Fosterville Gold Mine in their flotation tailings management, from design and operational phases through to rehabilitation implementation. Included within the paper are challenges which have arisen during the process, and a discussion on principals behind the designs and lessons learnt during operation of the facilities.Citation:Gray, L P, 2016. Full Cycle Tailings Management at Fosterville Gold Mine, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 369–378 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By M Jones, G Corder, A C. Keith

"Sustainable development has become an issue of ever increasing importance to the mining industry. The Ernst & Young (EY) mining industry risk radar regularly shows several sustainability elements in the top ten risks, with social license the number three risk in the 2014/15 survey. This is supported by the Fraser Institute survey results of 2013 showing that 36 per cent of responding companies indicated public opposition had affected their permitting and approvals process.Addressing these issues in a strategic way across a mining business that is then translatable to actions at operational level has remained an elusive goal in the industry. In addition the environment and community issues are commonly viewed as somewhat separate from financial and production issues and as a compliance cost rather than a value add. In their Harvard Business Review paper of 2011, ‘Creating Shared Value’, Porter and Kramer outline changes in thinking required for companies to improve their business sustainably through considering the societal issues impacted by their operations and products. Along the lines of ‘doing more with less’ companies’ value chains can be redefined to reduce energy, transport, water or other resource usage leaving additional resource for societal usage and/or reducing environmental impacts. This paper explores the linking of the holistic Five Capitals-based approach with the creating shared value (CSV) concept to help businesses unleash the benefits of innovation. Previous papers have demonstrated the potential for Five Capitals approach to create strategic value through sustainable development. Building on previous work, this paper provides an overview of the current status of holistic approaches to mine management and presents the application of the CSV concept on an African mine currently undertaking capitals-based strategic planning. The paper also demonstrates the value that has been created through utilising this approach and proposes improvements for changing the way the industry tackles and delivers benefits related to sustainability issues.CITATION:Keith, A C, Corder, G and Jones, M, 2016. Strategic sustainable development – creating shared value in the mining industry, in Proceedings International Mine Management Conference, pp 249-264 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 22, 2016

By C Jones

Ridgeway Deeps is a block cave (BC) located down dip of the operating Ridgeway sublevel cave (SLC) mine. The BC is located approximately 210 m vertically below the lowest SLC level and approximately 1100 m below surface. Due to the mine layout containing a number of common pieces of key infrastructure the activities of both were interlinked.When investigating project construction options for the BC, a number of potential risks were identified including a conflict of priorities between operational and project deliverables and the varying safety and work methods between an owner mining approach in the SLC and a potential contractor workforce in the BC. This led to a review of the construction philosophy and the opportunity to utilise the existing SLC workforce as the basis of all activities in the mine. It was identified that a number of synergies existed with the current SLC operators and mine supervision including common work practices and the opportunity to build on the unique SLC skills of the operators and supervisors which could then be used at other Newcrest caving mines.With the commitment to this philosophy of building on the existing SLC crews and supervision the number of employees reporting through the superintendent underground operations grew from 95 to 245. This increase led to a restructuring of the reporting and work requirements of the superintendent, foremen and shift bosses. In order for the foreman and shift bosses to focus on running the larger crew numbers for the full 12 hour shift the mine superintendent became a pseudo human resources manager taking over all non-mine focused activities including overtime allocation and work and behavioural performance management. In simple terms, ensuring there were competent bums on seats when and where required. As the additional workers were recruited to top up the existing employee numbers, their employment history was used to place them in the most suitable roles. For example, those with building industry experience were placed on the civil construction crews and those with a farming background were used as truck drivers, nippers or on the service crews. To cope with the increased number of new starters a number of key personnel were seconded from the crews into the training group to act as on shift trainers. This initially caused a reduction in mine performance as the main operators were reassigned but it proved a valid move as the time for new operators to reach acceptable levels was significantly reduced with safe operating standards being maintained. This paper discusses how the Ridgeway Deeps Project was delivered on time and under budget whilst at the same time retaining its position globally as an operation to be benchmarked against.

Mar 21, 2011

By T Belligoi

Diamond cores and drill chips provide the only direct physical evidence for ore containing rocks. Early characterisation of cores and drill chips is important as it provides critical information for downstream processing. Traditional characterisation techniques include visual logging by a geologist or analytic and spectroscopic methods but they are time consuming and can miss some important textural or geomechanical features.The goal of this work is to evaluate the application of image analysis to iron ore cores and drill chips and to suggest improvements to existing core-scanning and chip monitoring systems. Two samples of massive ore differing by their mineralogy and texture, as well as two different batches of drill chips, have been imaged and analysed. Results are compared in function of the imaging system and the classification algorithms.As a conclusion, despite the necessity for more testing and improvements in calibration and lighting, it is obvious that image analysis technologies can bring a lot of useful information in the perspective of a geometallurgical mapping of the deposit.

Jul 11, 2011

By A Hocking, S Henderson

Commonwealth of Australia (2016) defines rehabilitation as comprising “the design and construction of landforms as well as the establishment of sustainable ecosystems or alternative vegetation, depending upon the desired post-operational land use”. For open cut coal mines in Queensland and New South Wales, the question of how to apply this intent to pits at mine closure is repeated for hundreds of individual pits. In EISs, closure plans and public discussion, assorted treatments are proposed to rehabilitate pits. While some aspects of final voids have been intensively studied, there is little guidance on how to choose a final void treatment option that delivers the optimal outcome against rehabilitation goals. For example, in the Bowen Basin and Hunter Valley commonly proposed rehabilitation actions include reducing the angles of pit walls; however, with few voids successfully rehabilitated to date there is limited understanding of what different wall slopes will achieve.CITATION:Henderson, S and Hocking, A, 2018. A decision framework for comparison of coal void rehabilitation options, in Proceedings Life-of-Mine 2018, pp 127–130 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By R Jacobs

"The Jaguar project is relatively unique in that it was evaluated, financed, built and operated to completion within the last ten years, providing the opportunity to holistically review and reconcile expectations against the actual outcomes. It is a case study that allows wider conclusions to be drawn with respect to the risks and opportunities involved with project evaluation and execution.Jaguar is located in the Leonora Mining District of Western Australia and was commissioned in mid-2007 as an underground accessed, single high-grade volcanic-hosted massive sulfide (VHMS) deposit with an on-site concentrator, producing copper and zinc concentrates exported via the Port of Geraldton to South-East Asian markets.The feasibility study (FS) had several iterations (JML, 2005a); the last dated July 2005 was specifically targeted to secure project funding, and summarised the reserves-only portion of the resource and its planned exploitation. The commissioning of the mine was the transition for the owner Jabiru Metals NL from junior explorer to producer and the project was the dominant asset of the company.Jaguar operated through several significant deviations from the linear project plan set out in the FS, including the Global Financial Crisis (GFC), a corporate takeover and disruption to the mine plan from the onset of material geotechnical issues. Whilst the GFC or mining disruption were not specifically predicted in the FS or peer reviews, the generic effects of the events were assessed in the project risk assessment and they influenced subsequent management decisions. In parallel to the internal project-specific risks, the short planned life of Jaguar was a risk to the continuation of the corporate entity which was being addressed by significant investment into brownfields exploration to extend or replicate the project, and ultimately added value such that attracted a corporate takeover.Holistically, the project delivered the returns predicted in the FS, but in a much different guise than was expected. This paper will describe the reality of operations compared with the study predictions and expectations through the perspective of the project and corporate risk assessment.CITATION:Jacobs, R, 2016. Jaguar base metals project case study – has reality reflected the study?, in Proceedings Project Evaluation 2016, pp 86–97 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 8, 2016

By J P. Moodie

Recent trends in flotation technology are briefly reviewed. These show that considerable development has been made as the operators, suppliers and technologists have responded to the challenges of the industry. Most of these advances have been based on empirical and phenomenological methods. There is a considerable opportunity to make further advances through a more fundamental, scientific approach. Some of this work is discussed and, although progress is being made on this front, industrial uptake has been somewhat slow. A number of specific issues facing the industry are discussed.

Jan 1, 2005

By M Parcell

"Ventilation risks in an underground mine have essentially remained the same for centuries, yet theevidence suggests that there are many coal mines that have failed to adequately control these risks.The conduit for the knowledge learned by previous generations exists in the mining legislation. In an ideal world, mines would not need legislation to tell them what to do; they would resolve the risks to an acceptable level so as to protect the safety of persons in the mines based on the acquired knowledge. There will be some who have been personally aff ected by a mining disaster but for the majority they will be remembered as a vague recollection of an event from long ago. The mining legislation is the repository for the knowledge and outcomes from inquiries of past disasters. The challenge for the current generation, and the generations to come is to appreciate the legislation that exists, so as to not ælearn the hard wayÆ. In reviewing most disasters there is comment or discussion on the adequacy of the legislation, which ultimately results in some amendment to the law. For each person, there is an increasing responsibility to ensure that the same mistakes are not repeated. Understanding the legislation, its history and its purpose is the fi rst step in ensuring thatventilation risks are eff ectively managed. Failing to do this will be disastrous. This paper discussesthe relevance, importance and potential pitfalls of coal mine ventilation regulation."

Jun 1, 2012

By M Alston

Organisations’ incident classification processes are plagued by the overclassification of events, often leading to excessive workloads and suboptimal outcomes. This presentation addresses the pressing need to rethink how incidents are classified to maximise organisational learning and minimise systemic risk. A major issue in the current incident classification landscape is the tendency to classify events at high levels, overwhelming organisations with investigations they cannot efficiently handle. This results in inadequate risk reduction and learning opportunities. The link between injury classification and investigation methods further compounds these problems, creating unnecessary administrative clutter. Challenging the misconception that every event, no matter how minor, requires a comprehensive investigation, this presentation advocates for a shift in perspective. The key recommendation is to decouple injury classification and risk matrices from the decision-making process regarding what and how to investigate. Instead, the emphasis should be placed on identifying opportunities for organisational learning and risk reduction. Organisations can streamline their incident management processes by adopting a more pragmatic approach that aligns incident classification with the organisation’s investigation capacity. This transformation focuses on achieving meaningful outcomes, enhancing safety and improving performance. This presentation provides an innovative process for organisations to revamp their incident classification practices, enabling them to harness the full potential of incident data for learning and risk mitigation. It highlights the importance of aligning incident classification with the opportunity for organisational learning, ultimately leading to more effective incident management and enhanced safety outcomes.

Apr 16, 2024

By D J. Williams, G W. Wilson, S, A B. Tran

A comprehensive field program was implemented to evaluate the internal structure and hydrology of two full-scale waste rock piles. The excavation of waste rock dumps for in-pit disposal at the two mine sites provided an opportunity to characterise the in situ properties of the dumps given contrasting geologic and climatic settings. The internal structure and materials within the dumps were observed and sampled as the waste rock piles were being excavated and placed in the open pits for permanent closure. The field program was designed to fully characterise the structure and material properties of the waste rock. The alteration of the material by physical and chemical weathering was also observed. Samples were analysed for paste pH, water content, grain size distribution and geochemistry. In situ density and matric suction were also measured. Soil water characteristic curves and saturated hydraulic conductivity were measured for representative materials. These properties were used to predict seepage pathways through the waste rock and the resulting outflow geochemistry using the finite element model SEEP/W. The materials in the dump at Site 1 were predominantly fine-grained in texture and highly weathered. The presence of dipping beds with alternating coarse and fine materials was evident throughout the profile of the dump. The structure of the waste rock appears to have an impact on the hydrologic pathways within the waste rock pile. The material in the dump at Site 2 was found to be competent and resistant to particle size breakdown. The particles range in size from clay size to large boulders with the median particle size being approximately 125 mm in diameter. The coarse-grained texture of the waste rock resulted in a loosely packed arrangement of coarse particles with little matrix material infilling the pore spaces between the coarse-grained particles. Seepage modelling for Site 1 was completed to predict seepage paths based on observed structure and hydraulic properties measured in the laboratory. The modelling showed that materials with a fine grain size distribution become the dominant pathways for flow through the waste rock pile. The modelling also showed that layers with high silt and sand contents are subject to the highest flow rates. Finer grained clay rich layers have a low hydraulic conductivity and do not convey large volumes of water. Alternately, coarse gravel and cobble materials are unsaturated under values of matric suction that approach the residual water content of the material and do not transmit liquid water. The seepage modelling together with the results of the geochemical analysis show that the dominant particle size that receives the most fluid flow and flushing ranges from fine sand to silt, corresponding to materials with air entry values ranging between 5 kPa to 50 kPa.

Jan 1, 2003

By J Durbin

To effectively plan for closure, we must have an end-point in mind. To undertake meaningful rehabilitation, a post-mine land use (or uses) must be known. However, it is becoming more apparent that the end-point or “goal-posts” are shifting - and may continue to do so throughout the life of a mine. As well as being safe, stable and not causing environmental harm, post-mine land uses should always be sustainable, achievable within the given land capability, and they should involve stakeholders in their design and development.The majority of mines in Australia, and around the World, were historically expected to return disturbed land to either native ecosystem or agriculture/forestry practices. However, examples of highly successful final land uses suggest that today’s focus on closure includes not only minimising future liability and impact but also – and importantly – a move towards the creation of economic opportunity (Murphy and Heyes, 2016).CITATION:Durbin, J, 2018. Planning for (not so) final land use, in Proceedings Life-of-Mine 2018, pp 110–112 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By H Chalcraft, T D. Mullen

Conditions encountered at a recently completed brownfields mining project provided valuable insight into, and development of, techniques for working in and around known underground mining voids in an open cut environment. The careful application of underground blasting principles to a pit environment and successful excavation whilst maintaining appropriate stand-off distances were two primary areas of innovation enabling the success of the project.Mary Mac Hill is a gold deposit situated less than 2 km south-west of the town of Laverton, Western Australia. It is owned and mined by Crescent Gold Limited. Previous underground mining by various other mining companies has left an extensive network of underground horizontal development, subvertical stopes and shafts, some of which daylighted at surface. This was identified as potentially posing substantial risks, which would prevent the application of conventional mining methods. Two major stopes were located under a hard banded iron ridge topped by a peak of cap, connected variously by narrow drives and vertical development. Due to the proximity of the first of these stopes to the surface, its dimensions and governed by procedures and advice provided by externally engaged engineers, Crescent Gold could not access the area of the ridge immediately overlying the stope using conventional open cut mining methods. This was the first of many hurdles surmounted in mining this deposit.The following report outlines how the challenges this geometrically complex deposit presented. Solving these problems enabled the team to mine the contained gold ore to a completed design, without subjecting personnel or mining equipment to harm due to a void breach incident. This paper outlines the numerous complications and difficulties Mary Mac Hill posed and explains the strategies developed to overcome them. The report also presents technical mass blasting details explaining two of the critical crown pillar blasts.CITATION:Mullen, T D and Chalcraft, H, 2012. Mary Mac Hill - The challenges and strategies of successful open cut mining: A complex underground gold deposit riddled with a network of complicated voids, in Proceedings Eighth Open Pit OperatorsÆ Conference , pp 89-96 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 18, 2012

By P Card

Some project managers accept unsatisfactory economic evaluation modelling because they are unaware of what constitutes good practice. They tend to leave it to the evaluation specialist or others to decide. The AusIMM has published on its website a draft set of guidelines for technical economic evaluation which will allow these project managers to take control and demand worldÆs best practices.The style of the guidelines is described and the source of a worked spreadsheet example in Excel is given.Economic evaluation in project management is described. A simple test for the acceptance or rejection of evaluation work is offered. The nature of modelling and evaluation in each of the three study phases of concept, prefeasibility and final feasibility are described. Suggestions on the selection of specialists for each phase are given. The three levels of evaluation thinking are described, namely, modelling, valuation and evaluation. Finally the meaning of æfinancial analysisÆ is explained.The conclusion is that æthe role of an economic evaluation specialist is to create models and evaluations for the whole project team to readily understand and use: it is not to create models for his/her own useÆ.CITATION:Card, P, 2012. What project managers must demand from an economic evaluation!, in Proceedings Project Evaluation 2012 , pp 173-176 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 24, 2012

By Ramsay WRH, Morand V

Structural, mineralogical, and textural data from the Tarnagulla Goldfield demonstrate that the area has undergone three significant phases of deformation. The first phase of deformation (Dl) predates the intrusion of the Tarnagulla pluton, which has been dated using K/Ar as 391 ¦ 5MY. We regard this pre-granite deformational event as the major regional deformation. Gold-bearing quartz veins have been deposited in dilational sites on west-dipping reverse faults. These sites demonstrate a geometry related both to faulting associated with Dl and the plunge of the Fl fold axes. This evidence, together with chronology of unmineralised ? D2 and D3 faults, the absence of quartz veining associated with D3 events, and the deformation of carbonate-quartz-biotite-sulphide aggregates within Sl by later S2, lead us to conclude that the bulk of the mineralisation was essentially syn- or late Dl. S'80 values for fluids in equilibrium with vein quartz from Central Victoria have indicated equivocal support for either a magmatic or metamorphic origin. Our evidence supports a pre-magmatic origin for mineralisation at Tarnagulla and hence tends to favour a metamorphic fluid source.

Jan 1, 1995

By N Taylor, P Hewitt

The Northern Beaches Storage Project (NBSP) is part of Sydney Water’s SewerFix™ Program to improve the wastewater system and protect public health and the environment. It was built by the SewerFix Wet Weather Alliance (the Alliance), a partnership between Sydney Water, RPS, MWH, Parsons Brinckerhoff and United Group Infrastructure.The project temporarily stores excess wastewater diverted from the Narrabeen Submain during wet weather. The project considered a below-ground storage facility, which involved constructing a deep tunnel from Brookvale to Fairlight, connecting into the Northside Storage Tunnel and a storage tank, which was subsequently adopted and constructed.The storage tank scheme included a pumping station and inlet and outlet pipes installed by microtunnelling. The storage tank site is in the Brookvale industrial area situated in an area of deep marine sediments overlying Hawkesbury Sandstone at about 30?m below ground. Microtunnelling for the inlet pipe was conducted from a 12?m deep jacking shaft. The jacking shaft and 14?m deep pumping station excavations were carried out from within secant pile earth retaining structures adjacent to existing buildings.Construction activities had the potential to cause settlement of the adjacent buildings. During excavation and microtunnelling the water ingress, adjacent groundwater level and settlement of the adjacent buildings were monitored. The monitoring data was assessed against an action plan, which modified construction activities as required to minimise the risk of damage to buildings from settlements caused by lowering of the groundwater table outside the excavations. The secant pile construction, excavation, microtunnelling and pumping station construction proceeded without incident or damage to adjacent buildings.This paper highlights that tunnel/underground options should be considered during options development, describes the original storage tunnel scheme and presents details of the successful microtunnelling and deep shaft construction adopted on the NBSP.CITATION:Taylor, N and Hewitt, P, 2014. Tunnelling on Northern Beaches Storage Project, Sydney, to improve water quality, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 451–458 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By A Fyans, B Ghahreman-Nejad

This paper discusses the method and results of an options study into selection of the optimal form for a 130 m high tailings/water retaining dam, located in a region of high seismicity in central Iran. The proposed dam is part of a planned expansion project for Sarcheshmeh Copper Mine (SCM), which after construction will provide 550 million tonnes of additional tailings storage over the next 27 years. Geotechnical investigation at the proposed site indicated that adequate suitable low permeability materials (i.e. clay) were not available in the immediate vicinity of the dam site and would need to be imported from a distance of well over 10 km (direct). Given the magnitude of the estimated quantity of material and construction cost it was considered prudent to compare the cost of alternative dam design options for the proposed storage. A total of five dam design options are considered including a conventional rockfill embankment dam with an upstream sloping earth core (ECRD), a geomembrane face rockfill embankment dam (GFRD), a sloping asphalt core rockfill embankment dam (ACRD), a roller compacted concrete dam (RCCD), and a filter rockfill embankment dam for tailings storage together with a separate smaller earthfill core rockfill dam (ECRD) located downstream for storage of decant water. The risks, costing and design of all options are discussed in detail and the outcome of the study is presented.CITATION:Ghahreman-Nejad, B and Fyans, A, 2018. Optimum embankment design for a tailings dam, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 427–438 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

The longwall system with caving is the most common mining system in Polish Collieries and the extraction is carried out simultaneously on several levels and in different seams. The extent and diversity of the methane hazard occurring is strictly connected to the specific geological and gas conditions as well as to the applied mining methods. Taking these factors into consideration the following methane drainage methods are applied as additional means of combatting the methane hazard in Polish gassy coal mines: 1. predrainage by means of boreholes drilled from the surface, 2. predrainage from stone drivages and devel- opment workings, 3. degasification of coal extraction workings, and 4. degasification of sealed-off areas/old goaves. Predrainage gave satisfactory results when holes were drilled from the surface or from underground workings, but only to depths to 300 m. It was necessary to adapt methane drain- age methods to the geological and mining con- ditions as gassiness increased with depth. The results of methane capture, both pre- drainage and post drainage were obtained by investigating several gassy mines.

Jan 1, 1982