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By B Miles, D J. Williams, J Ahn, T A. Vangsness

The flooding of open strip coal mines in the Bowen Basin and Hunter Valley Coalfields of Eastern Australia has the potential to soften the spoil and floor materials to produce “mud”. This mud can act as a slip plane or weak zone when spoil is dumped into it, resulting in geotechnical instabilities. It is therefore important to understand the mechanisms and degree of degradation likely to occur within coal mine spoil of different qualities.To investigate this, five clay mineral-rich coal mine spoil samples were collected from the Bowen Basin, and each sample was subjected to wetting and drying cycles to simulate degradation that could be expected on wetting-up in situ, with their particle size distribution analysed both before and after degradation. These results were compared with the results of a modified slake durability test, in which the entire sample was tested.The paper presents the results of the accelerated degradation and modified slake durability tests on each of the five spoil samples. These results were related to the physical and geochemical characteristics of the samples, which highlighted their importance. The modified slake durability test may be used to rapidly simulate the expected in situ degradation of coal mine spoil on wetting-up, enabling susceptible spoil materials to readily be identified.CITATION:Vangsness, T A, Williams, D J, Ahn, J and Miles, B, 2018. Accelerated degradation and modified slake durability testing of clay mineral-rich coal mine spoil, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 83–96 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

By T Sprague, D Pateman

"The Gosowong Gold Project is owned and operated by PT Nusa Halmahera Minerals (PT NHM), an Indonesian company 75 per cent owned by Newcrest. It is located on Halmahera Island, in the North Maluku Province of the Republic of Indonesia, approximately 2450 km north-east of the national capital, Jakarta (Newcrest, 2017).Kencana is one of two underground gold and silver mines at the Gosowong Operation where ground conditions vary from competent to very poor. Development headings occurring in poor rock mass conditions require high capacity ground support including long tendon cable bolts. Manual installation of cable bolts in these development headings has been a time consuming process due to borehole collapse, blockages requiring subsequent re-drilling and a minimum eight hour grout curing time interval. The installation of cable bolts including the setting, plating and tensioning can impact the critical path for development heading advance resulting in development cycle delays.A review was conducted by PT NHM on current industry practices for alternatives to manual cable bolting. PT NHM subsequently approached Minova to assist with the development and trialling of self drilling anchors (SDAs) installed using jumbos with a rapid setting pumpable resin, CARBOTHIXTM. A series of system development trials were conducted and a reliable bolting system was developed utilising the existing jumbo drilling fleet with minimal required modifications.The system developed was a ‘one pass’ bolting process to install and grout SDAs using a two component resin with a remote, mechanised system. Improvements achieved from the system include: eliminating hole closure issues and more immediate support in poor rock mass effectively reducing personnel exposure to poor ground conditions by removing the requirement to access the drive backs reducing grout set time with full installation times for 6 m SDAs averaging 25 min.The resin grouting system has now been successfully implemented to effectively manage areas of poor ground conditions and to accelerate advance rates in high priority headings.CITATION:Pateman, D and Sprague, T, 2017. Development and implementation of a long tendon bolting system utilising resin grouting technology, in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 79–84 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 16, 2017

Times are changing for the mining industry. Civil society is demanding that miners pay more attention to the ways they impact on, and engage with, communities around their mines. Miners, in turn, are being forced to adapt and learn new social skills for which they were not originally trained. They are doing so in the middle of a broad resources boom, which is adding short-term operating challenges at the same time as miners need to be developing thoughtful solutions to longer term community issues. This paper examines a number of the issues that now loom on the horizon of mining companies. These include: human resources challenges and the crisis in minerals education; continuing community and social expectations of the resources industry and the impacts they will have, for example, on product stewardship, greenhouse gas emissions and the use of increasingly precious water resources; and current impediments to mineral exploration spending.It is concluded that the greatest challenge for the minerals industry is to develop a stronger cadre of local leaders and for the larger global miners to empower their local management to take on stronger public leadership responsibilities. There is a need for executive leadership to remember both the longer term and shorter term cyclical nature of the mining industry in developing solutions to community problems. Above all there is a compelling case for mining industry leaders to be more actively engaged with the wider community in the resolution of these issues.

Jan 1, 2005

By M Fahey, A B. Fourie

Over the past ten years, the mining industry has witnessed the introduction of a new and innovative mine filling technique known as paste fill, which consists of placing full stream tailings with small amounts of binder and water into underground stopes. Paste fill has benefits over traditional backfill methods, such as higher solids contents than hydraulic fill and easier transportation than rock fill. From a geotechnical perspective, the behaviour of very fine material in a fully saturated state can be complex, particularly when binder is added. Previously, there has been no rigorous solution to understanding the paste fill deposition process, resulting in uncertainty regarding critical aspects such as barricade load calculations. This uncertainty has the obvious consequences of potential barricade failures (including at least 12 over the past four years), and for many operations attempts to deal with this uncertainty has led to excessively conservative filling schedules, restricting production. This paper presents an application of Minefill-2D, the first rigorous model capable of representing the paste fill deposition process. The model couples the processes of material accretion, consolidation and cement hydration to calculate the distribution of stress around a stope (including the total stress applied to barricade structures) during filling. Minefill-2D is a finite element numerical program, which has been verified using laboratory element tests, centrifuge tests and in situ measurements (Helinski, 2008). The authors present a sensitivity analysis, carried out using the model, to demonstrate some of the critical and less critical aspects relating to paste backfill deposition. The results of this sensitivity analysis are used to devise a fill management strategy that can be utilised to minimise the risk of barricade failures and maximise fill rates where appropriate.

Jan 1, 2008

By D Connelly

Magnetite orebodies generally means mining lower grade iron ores, crushing and grinding with significant energy costs in processing and the capital costs being significantly higher than for direct shipping ores (DSO). Overseas, the mining and processing of magnetite ores has a long history of production due to the lack of DSO deposits. This raises the question as to why the new magnetite projects have been so problematic and also whether there is a future for the long list of potential magnetite projects in Australia.The quality of the magnetite concentrate product is superior to most DSO products and the magnetite contains energy benefits when converted to hematite in sintering or pelletising. The industry’s hopes for new projects have been dashed and questions are being raised as to the financial viability of such projects.A comparison of Grange Resources Savage River, Arrium’s Project Magnet, the Sino Iron Project and Gindalbie’s Karara Iron Project is used to understand the differences between the projects and why some are more successful than others.CITATION:Connelly, D, 2015. What is the future for magnetite projects in Australia and why have some of the new projects been so problematic?, in Proceedings Iron Ore 2015, pp 107–114 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By A Hacket, M Haest, I Vitins

Infrared spectroscopy has the ability to accurately measure mineralogy of drill cores, allowing for better spatial characterisation of iron ore deposits and potentially improving the prediction of key mining and processing parameters at the deposit scale. BHP Billiton Iron Ore is using infrared spectroscopic drill core logging to provide fast and accurate mineralogy for diamond cores and reverse circulation (RC) samples.Mineralogy can be predicted from infrared spectroscopic drill core data with errors on estimates ranging from six to 12 weight per cent. The error on the clay estimates is significantly lower than for hematite and goethite content estimates. This manuscript presents the results from a study on a bedded iron ore deposit, hosted in the Brockman iron formation, for which infrared spectroscopic data were collected on all of the diamond and RC drilling. Results show that these mineralogy estimates improve drill core logs, the geology model and the metallurgical block model.CITATION:Haest, M, Vitins, I and Hacket, A, 2013. Infrared spectroscopic drill core logging - making inroads to deposit scale 3D mineralogy, in Proceedings Iron Ore 2013 , pp 251-258 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By T Schrimpf, I Bryan

The life cycle of a mining project begins with initial regional exploration and ends with mine closure and rehabilitation. Between resource definition and the commencement of mine construction is the study phase. In this phase technical concepts and processes are defined, evaluated and assessed with the aim of establishing whether the deposit is economically feasible. The study phase usually involves various steps from a concept/scoping study to prefeasibility and ultimately definitive feasibility study. The complete study phase can take several years. Although the costs for studies are low in comparison to actual construction and operating costs of a mining project, they are significant especially for junior exploration and mining companies advancing projects to the point of being funded.The studies aim to determine selected parameters for the project, eg mining and processing methods, operating strategy, etc and provide a roadmap for project development ahead. Although mining studies are of the utmost importance for the mining project and the project owner, they are usually carried out using a conventional engineering approach: the consultant or design engineer works to a defined scope of work. The resulting design might be based on good engineering, but might often also fail to provide the solution for the project owner that delivers the best shareholder value. An alternative to this more traditional approach to project evaluation is what we have termed a value engineering approach. Value engineering is a creative, organised effort, which in the case of a mining study analyses the requirements of the study for the purpose of achieving the essential outcomes with the highest shareholder value. The outcome of a study is a concept that delivers the highest achievable value of the resource project and shows the way ahead to realise this value. Through a group investigation by experienced, multi-disciplinary teams the value of the resource is improved through the study of alternative options, methods and processes. The scope of the study is not limited to a narrowly defined engineering scope, but to the creation of value.The study commences with the identification of key value drivers and risks, based on the available information (drill data, geotechnical data, metallurgical test work, etc). This enables the quantification of key uncertainties, risks and value adding opportunities. Study efforts concentrate on key value drivers and are not unnecessarily spent on side issues. This approach can significantly reduce the time frame and costs for the study phase.This paper describes in more detail RMDSTEMÆs value engineering approach to mining studies and illustrates it with examples and case studies.CITATION:Schrimpf, T and Bryan, I, 2012. The application of value engineering principles to mining studies, in Proceedings Project Evaluation 2012 , pp 163-170 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 24, 2012

Real-time data collection and plant historians are becoming common place in mining and processing plants. This vast quantity of data must be turned into easily accessible and actionable information for all levels of the organisation.Queensland Nickel use a combination of Microsoft and SAP business intelligence tools to collect, cleanse, aggregate and present plant information to the appropriate people for supporting decision making in the business. SAP Business Objects, for visualisation, and SAP MII, for integration, allows complex and accurate metrics to be delivered as real-time dashboards. Designing a rigid data management architecture to segregate the data collection, integration and logic and visualisation into distinct logical layers, allows for rapid report development and greatly assists with IT maintenance, while also minimising the complexity of any customised programming. This type of architecture ensures a common data source for all business reports, ensuring one version of the truth. The past few years at Queensland Nickel have seen process and maintenance engineers spending considerably less time collecting and integrating data and spending more time analysing what is happening in the plant. Real-time reports and dashboards have been developed around the business needs rather than around the data. Two years ago Queensland Nickel introduced an employee bonus scheme based upon meeting monthly performance targets; an easy to use dashboard that allows everyone, from operators through to management, to monitor these metrics day-to-day.

Sep 26, 2011

By C Tapia Cortez, A G. Dempster, R Fradet, S Saydam, T de Roche, R Shishko, J Coulton

Human ventures into space are entering a new phase in which missions formerly driven by government agencies are now being replaced by those led by commercial enterprises – in launch, satellite deployment, resupply of the International Space Station and space tourism. In the not-too-distant future, commercial opportunities will also include the mining of asteroids, comets, the Moon and Mars. This research examines the role of off-Earth mining in a growing space economy. In this investigation, the term ‘mining’ is taken to embrace minerals, ice/water and other in situ resources. As the off-Earth mining initiative could be the engine that drives the space economy, it would be useful to understand what off-Earth mining market conditions and technology requirements are needed for that economy to prosper. These specific elements are studied in the wider context of creating an economy that could ultimately support a sustainable Mars colony. The methodology for developing the model focuses on the extraction of ice from the surface of Mars to produce propellant and water for life support for a possible colony.CITATION:Saydam, S, Shishko, R, Tapia Cortez, C, de Roche, T, Fradet, R, Coulton, J and Dempster, A G, 2015. An integrated economics model for in situ resource utilisation in support of a Mars colony, in Proceedings Third International Future Mining Conference, pp 305–312 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 4, 2015

By G S. B Karunatillake

Following a pre-feasibility study, Mount Isa Mines commenced a feasibility study on the deposit of the George Fisher Mine in May 1997. Board approval was granted in May 1998 to construct a 2.5 million tonne per annum mine and to upgrade existing concentrator and smelter facilities. The world-class George Fisher zinc-lead-silver deposit is located approximately 22 kilometres north of the city of Mount Isa, in north-west Queensland and is 2.6 kilometres north of the existing Hilton Mine. It will be a large-scale underground mine, sustaining a profitable zinc-lead-silver business in Mount Isa for at least ten years. This paper will outline the details of the mine that was developed during the feasibility and design phase. It will include a description of the mining methods, ventilation, fill, ore handling, services and infrastructure. The utilisation of existing assets and the development of innovative ideas were essential to the successful economic development of the George Fisher Mine.

Jan 1, 2000

The paper provides an overview of the development and content of APCOM symposia since their inception in 1961. This development is set within the context of the academic environment in which much of the research published at APCOM symposia is conducted. This environment includes rigorous external assessment of research quality at national levels and against international benchmarks, which carries significant consequences for funding and for the continued existence of the academic minerals industry disciplines. Adverse consequences that undermine the academic provision of mining and resource engineering will impact negatively on the minerals industry by reducing the level of research and education resources available to it.The traditional reductionist approach to research is contrasted with the inter-disciplinary approach that is required to address the complex systems problems that the minerals industry will have to address to ensure its technical, economical and environmental sustainability. Such an approach offers a means of raising research profiles, of establishing mutually beneficial academic-industry engagement and provides an opportunity for APCOM to take a lead role in identifying the research and development agenda for the future

Sep 26, 2011

By M Olsen

"Segregation of conveyor roadways is a ventilation practice that is being increasingly applied in Australia. It is largely driven by the legislated requirements in Queensland pertaining to separation of escapeways from the mine. This legal requirement was based on a recommendation from the Moura No. 2 WardenÆs Inquiry (Windridge, 1996) into the mine disaster that claimed 11 lives. The report recommended: ... the introduction of a requirement for all underground mines to have one intake airway that is completely segregated from other parallel intake airways so as to provide two separate means of egress from the mine via an intake airway.This recommendation seeks to assist mine workers in escape from a mine after a fire by providing them with an airway that is free from smoke or contaminants.The concept of an airway being æcompletely segregatedÆ is an ideal that is challenging to implement in practice when considering the effect of leakage. The practice of belt segregation is concerned with the potential for fires in the belt roadway although there are numerous other potential fire sources in underground coal mines. A review of segregation practices has been conducted applying ventilation engineering principles. Four different scenarios have been analysed with regard to the effectiveness of the segregation stoppings in preventing potential fire contaminants migrating to other parts of the mine. The results show that in some cases the benefits of segregation to a person evacuating a mine in the event of a fire range from beneficial to detrimental. This is influenced by many factors including the location of that individual in that particular mine. There is room for improvement in the design and implementation of escapeways in underground coal mines. Escapeways need to be planned and designated with regard to the potential sources of fire, pressure differentials between escapeways and the operational practicalities of maintaining the pressure differential between them.CITATION:Olsen, M, 2013. Belt road segregation and escapeways - Compliance or risk management?, in Proceedings The Australian Mine Ventilation Conference, pp 311-318 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 1, 2013

By P J. Chapman

Recent catastrophic failures of tailings storage facilities (TSFs) continue to highlight the need for a detailed understanding of failure modes and the defences that are in place within the design to mitigate the failure modes. However, in many cases the instrumentation devices and monitoring approaches selected during operation do not link back to the design defences and inappropriate or redundant instrumentation is often installed. Candidate instruments and monitoring approaches (critical controls) are presented and matched to critical failure modes, with clear linkages to the intent of each instrument/monitoring approach. Commentary on where complementary measurements with independent technology types are recommended to provide greater assurance of trends to the design engineer or TSF owner is also presented. In response to the recent TSF failures, an increasing focus is being placed on instrumentation and monitoring relating to slope instability and safeguarding against the potential for static liquefaction, using a critical state soil mechanics framework. To support selection of appropriate zoning within a stability model, three complementary devices are recommended – vibrating wire piezometers to provide an indication of pore pressure and allow the phreatic surface to be inferred, tensiometers to confirm the presence of unsaturated conditions (and hence low potential for undrained failure) and moisture content sensors to provide an indication of void ratio, and hence state parameter, in saturated zones. The combination of VWPs and tensiometers will provide complementary measurements in the saturated and unsaturated zones, and also provide information on the extent of any near-saturated zones, provided that sufficient instruments are installed.

Jul 1, 2021

By E Hawkins, S Sheldon

Block caving is becoming a more widely adopted mining method allowing for underground massive low grade orebodies to be extracted economically. Underbreak during cave propagation is difficult to predict in terms of recovery and is not well-researched due to the small number of caving operations. During mining of E26 Lift 2 (E26L2) block cave at CMOC Northparkes Mines, a wedge of high grade material failed to cave, even with the assistance of preconditioning and subsequent attempts to induce caving. The ultimate solution for recovery of the uncaved wedge was the establishment of the E26 sublevel cave (SLC), which commenced mining in 2015, with production following in 2016. The SLC provides approximately 1Mtpa to supplement the lowering grade of the current E48 block cave feed. Applying the sublevel caving methodology to recover block cave underbreak has proven challenging. The impact of the caving stresses and preconditioning of the wedge have caused production limitations requiring continual remediation throughout production of the E26 SLC. The dependence on remediation work created a roadblock to implementing precharging as the prevalence of brow loss raised concerns over the inability to hook up the charged ring. In 2018, a wireless initiation trial was completed in the E26 SLC over 24 rings. The trial showed that precharging was achievable in this environment and greatly improved the safety of charge up personnel.

Mar 15, 2021

By B Ghahreman‐Nejad, M Munro

Design of embankment dams often requires seismic analyses, or an assessment of earthquakeinduced ground and dam movements. There are a large number of cases where earthquakes have triggered sliding and lateral spreading of embankments, resulting in excessive crest settlements. In some instances, liquefaction and embankment failure has occurred resulting in loss of containment. Hence, evaluation of the effects of earthquakes on embankment dams is a critical design aspect. This paper discusses the methods and the results of a seismic liquefaction assessment and deformation analyses of a tailings dam. The tailings dam consists of a perimeter earth core rockfill starter dam which has been raised using upstream construction methods. The embankment raises (formed by an upstream clay blanket and an all-in rockfill body) are constructed over the impounded tailings, which are potentially liquefiable. Extensive field and laboratory tests were undertaken to assess the liquefaction potential of the tailings, and also determine the material properties required for seismic stability and deformation analyses. Numerical modelling of seismic liquefaction and deformation was carried out using FLAC (Itasca 2016) to predict the magnitude and spatial variation of deformations that may lead to an uncontrolled release of tailings. Primarily based on a parametric assessment of UBCSand and Finn-Byrne constitutive models, the results of the analyses are presented and compared for evaluation.

Jul 1, 2021

By S H. Burgmans, B Anderson

This paper aims to define the specific challenges relating to dredging fine tailings from an above ground storage facility for transferral to a mined-out pit. In addition, it compares dredging and mining perspectives on dredging of fine tailings.

Jul 1, 2021

One of the responsibilities of the Melbourne and Metropolitan Board of Works is to provide a sewerage system for the metropolis of Melbourne which now contains over 2.5 million people. In providing this sewerage system it was necessary for the Board to embark on a large tunnelling programme some 20 years ago. As a result of this extensive tunnel construction programme, tunnel boring machines and shaft sinking methods have been developed to cope with the soft ground and soft to medium rock found in the southern and eastern areas of Melbourne where the majority of the recent tunnelling has been carried out. While in the last few years radical changes in construction methods have not been made, development has continued and improvements have been made, which have enabled the Board to extend the limits of the ground conditions in which it can efficiently construct shafts and also tunnels with boring Machines.

Jan 1, 1976

By Ring R. J, Waters D. J, Vautier F. E, Fulton E. J

Laboratory leach tests have been carried out by the Australian Atomic Energy Commission to compare the effectiveness of Caro's acid (permonosulphuric acid) as an alternative oxidant to pyrolusite in the leaching of uranium ores. Results demonstrated that Caro's acid reduced acid consumption in leaching and the lime required for neutralisation of tailings liquor. The uranium extraction was unaffected by choice of oxidant.Following this study, Interox Chemicals Pty Ltd arranged a plant trial using Caro's acid at the Nabarlek uranium mill of Queensland Mines Ltd. The trial confirmed that significant savings in acid and lime usage can be achieved under plant conditions.Plant operations also demonstrated that Caro's acid has a number of significant operating advantages over pyrolusite.Queensland Mines Ltd have recently decided to convert their leaching process from pyrolusite to Caro's acid. The new system is expected to be fully operational by mid 1983.

Jan 1, 1983

The Jundee gold mining operation is located in the Western Australian Yandal Greenstone belt. Jundee is a mature operation encompassing multiple and complex underground ore resources, dwindling open pit reserves, large surface stockpiles, small satellite resources and two near-mine but stand alone process plants. The imminent completion of continuous open pit mining and the associated drop-off in total mill feed precipitated a review of the strategic mine plan and development of options that would optimise the exploitation of the remaining mineral resources and the utilisation of the existing plant and infrastructure.An initial review of the strategic decisions to be made, available options as well as the quantity, complexity and co-dependency of the strategic variables quickly led to the conclusion that an Operations Research style modelling approach would be appropriate. An 'off-the-shelf' program engine by the name of WHATSBEST! (LINDO Systems Inc.) was chosen on the basis of price, reputation and ease of use. The model was formulated with the unknown variables (being the ore mining rates) expressed as a proportion of the maximum achievable ore mining rate from each source. Costs were defined as variable or fixed, with this definition being a key aspect of the modelling process. The critical application of the model was in determining the optimal extraction rate of ore, the destination (ie Jundee or Nimary mill) and the sequence of extraction of each ore source that maximized the cash flow of the operation. The program was designed to be able to quickly derive an optimal result from the many variables, replacing the previous laborious iterative process of arriving at an acceptable answer by means of several large and static spreadsheet models. This paper presents the process of selection, formulation, application and scope of operation of the turn-key linear and non-linear program strategic model now used as part of the Jundee Operation strategic decision making process.

Jan 1, 2002

The Ernest Henry Mine is an open pit copper-gold mining operation located in north-west Queensland, Australia. It is owned and operated by Xstrata Copper with a current concentrator throughput of approximately ten million tonnes per annum. The pit will cease mining towards the end of 2010. Extensive surface diamond drilling has confirmed an extension of the orebody to depths of 1000 m below surface. A prefeasibility study was commissioned in late 2006 to investigate underground mining options with the preferred mining method being an inclined sublevel cave. In February 2008 mining of a decline commenced in conjunction with a feasibility study to further investigate the project. Work from the prefeasibility study indicates that an underground crusher, conveyor and hoisting shaft could be utilised to crush and transport broken ore from the sublevel cave workings to the concentrator. The study suggests that a production rate of five million tonnes per annum could be achieved and sustained for up to ten years. Ventilation designs and requirements will form a large section of the feasibility study. This paper will detail investigations of preliminary ventilation network designs of the proposed sublevel cave. Work has been completed using both Ventsim and VumA ventilation simulation packages. Ventsim was used to provide preliminary estimations and suggest alternatives for: surface fan duties;airflow characteristics (direction, velocity, pressure and quantity); andventilation network design in key mine areas. With mining activities reaching depths in excess of 1000 m below surface an analysis of heat conditions should be conducted. The VumA software package was used to model the thermal properties of the ventilation system. This model will provide a basis for the preliminary decisions on refrigeration requirements for the mine.

Jan 1, 2008