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The Pasminco mine at Rosebery in north western Tasmania is a medium sized underground base and precious metals mine. In April 1992 a major wedge failure of approximately 5000 t occurred in the backs of a main access drive to the 18 level H Lens orebody. This collapse prevented access to 190 000 t of ore which had been scheduled for production in July - August 1992. At the time of the collapse, the mine was in a transition period between mining small pillar remnants of several other orebodies and developing to the new deeper J Lens orebody.The development at this orebody was behind schedule and it was necessary to find a cost-effective and timely alternative to a 75 m bypass drive around the fall area.A Lysaght- Fletcher multiplate steel arch was available on-site from a deferred surface road project and it was decided to use this arch to regain access through the fall area. Due to the danger of continued minor falls, the entire 18 m long, 3.95 m high x 4.5 m wide tunnel had to be assembled in the 4.7 m wide x 5 m high accesss drive and pushed into the fall area as a single unit.

Jan 1, 1993

By D Brown, K Markovic

The world is becoming an increasingly complex environment to operate within. Adoption and evolution of technology is occurring at a rapid pace and operating spaces are growing in interconnectedness and interdependency. In mining this is evidenced by the large-scale adoption of autonomous machinery, intelligent systems, Internet of Things (IoT) devices, and robotics to realise benefits in optimisation, productivity, and safety. To enable continual delivery and growth in operational performance, and to realise the aforementioned benefits, a new approach for managing mining and metals is required (Mining Review Africa, 2023). This means that an already talent constrained workforce must learn to manage the complexity inherent, evolving, and growing in the environment (Abenov et al, 2023). A key skill that needs to be further developed and deployed to combat these challenges and to enable robust problem solving is that of systems thinking, which is already practiced in pockets within the mining industry. Experience and learning can be leveraged from other industries and their application of systems thinking to ensure that focus is maintained on areas where the benefits from which will be optimised. With targeted application, a workforce capable of effective systems thinking can be the catalyst to optimisation across mining organisations.

Sep 1, 2024

By G Bignall, I Chambefort, A B. Christie, A J. Rae, M P. Simpson

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. Key indicator hydrothermal alteration minerals formed from fluids of known fluid composition (neutral versus acid pH) and temperature have been mapped for New Zealand (NZ) geothermal fields by visible/near-infrared (VNIR) and short wave infrared (SWIR) reflectance spectroscopy. Smectite, interstratified illite-smectite and illite formed from neutral pH fluids have zoned distributions with higher temperature illite (>220ºC) in and around the upflow of chloride waters and low temperature smectite (<150ºC) on the margins (eg Ohaaki, NZ). In adularia-sericite epithermal deposits, Au-Ag veins are similarly surrounded by zoned clays, with mineralised veins enclosed by illite (eg Martha, NZ) or occurring at the illite/illite-smectite boundary (eg Favona, NZ). Reflectance spectroscopy is also highly effective in identifying minerals formed from acid fluids; both steam-heated acid-sulfate waters (eg kaolinite and alunite at Rotokawa, NZ), or magmatic-hydrothermal fluids (eg pyrophyllite and topaz at Ngatamariki, NZ). These same alteration minerals commonly show zoned distributions in high sulfidation epithermal deposits (eg Rodalquilar, Spain) and in lithocaps associated with porphyry deposits (eg Lepanto, Philippines). Thus reflectance spectroscopy permits the rapid identification of key alteration minerals that can be mapped at a high sample frequency and used as vectors towards mineralisation.CITATION:Simpson, M P, Bignall, G, Rae, A J, Christie, A B and Chambefort, I, 2015. Mapping hydrothermal minerals in New Zealand geothermal fields using reflectance spectroscopy (VNIR-SWIR) and application to mineral deposit exploration , in Proceedings PACRIM 2015 Congress, pp 243–248 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By S Tjerry, S Szylkarski, B Willis-Jones, I Dubinski

Achieving relinquishment of mining sites is becoming increasingly difficult, with a study by Byrne (2013) estimating that out of a set of 73 mining and metals sites around the world, less than ten per cent had achieved relinquishment over the last 50 years. The median forecast duration of time allocated for water management in the closure plans studied was approximately ten years, while the reality at the actual sites was a median duration of 22 years to date and growing.One of many challenges in mine closure planning is managing geomorphic stability of stream diversions. The challenge is to be able to demonstrate to regulators and the community that a proposed rehabilitation solution will be stable over the long term.During the mining operations, local watercourses and surface drainage can be diverted and managed using engineered channels and drainage structures. However, during the post-operations stage, the engineered channel and drainage may require modification to a more natural condition that will facilitate long-term environmental sustainability. Achieving geomorphic stability of a diverted watercourse is difficult, with the majority of stream diversions in Australia failing to meet expected design performance (White et al, 2013). Geomorphic stability is a complex process that is controlled by a combination of factors, including hydraulic flow conditions, geotechnical conditions and vegetation.This paper proposes that a fully dynamic and deterministic geomorphological model can be used to supplement the traditional empirical approaches to assess long-term geomorphic stability. The paper provides an overview of the geomorphological models and how they have been applied in engineering studies for forecasting future evolution of stream systems. The paper discusses the potential application of these models in the mining industry for forecasting and optimising surface water structures for the operations and post-operations stages of the mining cycle.CITATION:Szylkarski, S, Willis-Jones, B, Tjerry, S and Dubinski, I, 2016. Improving the reliability of stream diversion designs in mine closure plans using a morphological tool, in Proceedings Life-of-Mine 2016 Conference, pp 212–215 (The Australasian Institute of Mining and Metallurgy: Melbourne)

Jun 28, 2016

By O Dahl, I M. Platten, E J. Sides

Many narrow-vein gold deposits are characterised by a high to extreme nugget effect and the presence of coarse gold. They rank amongst the most difficult of deposits to produce an accurate and precise resource estimate. This contribution presents a case study from the Nalunaq Gold Mine in Southern Greenland. The mine commenced operation in May 2004 and is currently operating at a rate of 400 tonnes per day, to produce about 100 000 oz gold per annum from a total resource base of 1.2 Moz. Mineralisation is characterised by quartz veins that are hosted within a shear zone that is continuous over about 1000 m. The principal orebody is the Main Vein structure, which ranges up to 3 m in width, maintains an average dip of 35¦SE, and contains significant gold grades (1000s g/t Au). Gold particles are often visible, with 25 per cent being greater than 250 microns in size. Variography using underground development samples indicates a nugget effect of about 75 per cent. For the 2005 resource estimate, a 2D metal accumulation ordinary kriged block model was used to produce a global grade for the Target and South Blocks of the Main Vein. Grade control chip-channel samples are collected from æshantyÆ drive footwalls, and used as the basis for both the kriged block model and to determine the grade of individual stope blocks by peripheral weighted averages. Geology plays a key role in mining efficiency, given the locally variable nature of the ore zone.

Jan 1, 2006

By A Prill

Safety First and zero accidents are the targets most mines in Australia are aiming for, but manual processes and procedures limit the capabilities and response time in emergency situations. Even with a high safety focus, accidents and incidents still happen, too often with tragic outcomes. Dangerous areas, narrow roads and winding curves are all daily obstacles that threaten workforce safety. Every unforeseen event, such as traffic collisions and other accidents, puts lives in danger and weakens production. Safety must be guaranteed.

May 5, 2022

By A Purton, C Taylor, E Conroy

The spatial modelling of geometallurgical domains is an important step in the characterisation of an ore deposit allowing for the quantification of various rock types, their differing rock properties and the overall value of a project. The traditional approach to modelling such features is through the use of deterministic models, where a single estimate of the extents and structure of the ore deposit is mapped out by geologists based on available data and their interpretation of the geological processes. Any uncertainty in the layout of different domains is not accounted for and heterogeneities of chemical and physical properties of the orebody are likely underestimated. Spatial machine learning techniques can be used to derive geometallurgical categories, or classes, from multiscale, multiresolution and high dimensional measured rock properties. Subsequently, geostatistical simulations of these classes can be applied to obtain multiple equiprobable realisations that define the layout of the geometallurgical classes at unknown locations between boreholes, or domains. In-turn these realisations can be used quantify the uncertainties in the location of boundaries between different domains. The development of a workflow for defining geometallurgical domains and later geostatistically simulating them across the Orebody H; a complex stratabound Bedded Iron Ore deposit located in Western Australia’s Pilbara region is demonstrated. This could be used to identify zones of high uncertainty where collection of additional data might help mitigate or minimise risks and in turn improve forecast production performances.

Mar 22, 2022

The Callie Underground Gold Mine (Callie) is owned by Newmont Asia Pacific and located 531 km north-west of Alice Springs in the Northern Territory. Historically, stopes have been mined utilising a primary and secondary stoping sequence with cemented aggregate fill and rock fill respectively. Current and near-future mining will employ long hole open stoping with rib pillars and rock fill with a paste fill system approved to allow a higher extraction ratio from mid-2011. The Callie rock mass is of good quality with little or no mining difficulties during development and stoping to a depth of 1140 m below surface. Development is currently occurring at depth of 1360 m below surface. Stress damage previously observed only in secondary stope accesses is now observed in development unaffected by stoping stresses. A change in rock mass properties is being experienced with depth, with more pronounced and frequent joint planes. Also, other structures are intersected more commonly, such as lithological boundaries and fault zones. The 'Callie rock factory' mentality that has persisted for years is challenged. This paper covers an appraisal of the stress and ground condition changes at Callie. The appraisal outlines the mine design criterion that was developed and examines the transition from a low stress environment to one where stress damage is observed. Discussion includes a judgement on the rock mass damage observed in development, the dominant geotechnical factors influencing the change in ground conditions, and if a correlation can be made between the observed rock mass damage with stress through the use of numerical modelling.

Nov 25, 2010

By H Simpson, C Gimber

The financial evaluation of mining projects drives a whole range of decision-making regarding project viability, project design, operating models and closure philosophy. Net Present Value is a financial assessment approach that is pervasive across the industry and has been widely criticised for driving short-term thinking and leading to poor long-term outcomes and future unfunded closure liabilities. But are there alternative models and what are the impediments to their implementation? This paper aims to outline current and past mine closure practices in the mining industry and questions these outcomes given the changing shareholder investment requirement for alignment with sustainable Environmental, Social and Governance (ESG) goals. Examples are presented of closure programs planned and executed in the later stage of the life-of-mine and explores the benefits that could have been realised by integrating these into concurrent production operations. Examples of simultaneous mine development and closure execution and their benefits are presented, and their relevance to corporate investor branding. This paper also discusses the concept of investor project ownership through to sustainable closure and outlines alternative approaches to responsible, sustainable mine closure. We explore the current mining industry divestment practices to remove closure liability from the balance sheet. These underlying financial practices and Net Present Value approach to Mine Closure and alternative approaches are discussed.

Aug 2, 2023

By T Peters

The Kibali Gold Mine is currently comprised of several open pits, a 3.5 Mtpa underground mine and a 7.5 Mtpa processing plant. Development of the underground operation commenced in December 2012, with initial access established through twin surface declines, followed by the commencement of a blind sink 8 m diameter rock hoist shaft in March 2013. Stope production started in December 2014 with ore and waste trucked to surface. The 755 m deep blind shaft sink was completed in August 2015 together with the cutting and equipping of three main station levels. Two of these levels provide access for the establishment of the underground materials handling system as well as the main dewatering system for the mine. This paper covers the process of determining the optimal location of the Kibali hoisting shaft relative to project-specific critical factors, and then focuses on the design and implementation journey associated with the off-shaft development that essentially encompasses the Material Handling System (MHS) for the mine. The journey starts from the findings of the previous owners Feasibility Study (FS), a subsequent Optimised FS, followed by detailed engineering through to implementation. It was identified during implementation that a significant change in the designed off-shaft layout was required following detailed underground geotechnical and hydrogeological investigations. In addition, the paper provides details on the MHS performance since commissioning to steady state, and on key learnings relating to the overall project process.

Mar 29, 2023

By Raczej I, Defant M

Pre-Miocene igneous rocks from the Phili pine island arc are characterised by 87Sr/86Sr and 143Nd/144Nd ratios typical for intra-oceanic island arcs where sediment involvement in the magma genesis was minor. Lead isotopic ratios are similar to Indian Ocean MORB (Mukasa et al., 1986a,b). Pliocene to recent volcanics, however, have more radiogenic Sr and Pb and less radiogenic Nd, except for the volcanics of the Bicol Arc, which have similar isotopic signatures as the Pre-Miocene rocks. We suggest that Pre-Miocene magmas and Bicol-Arc magmas have been generated in response to the subduction of the Philippine Sea Plate, their isotopic characteristics reflecting the composition of Philippine Sea crust. The Bataan arc magmas may reflect the larger amounts of sediments available for subduction in the South China Sea, while magmas of the Mindoro Arc, which are characterised by the most radiogenic Sr and least radiogenic Nd, may have been contaminated by slivers of the Mindoro-North Palawan terrane, which have been carried down to mantle depths after the collision of this terrane and the Philippine arc in Miocene (McCabe et al., 1982). This interpretation implies that Nd (and by inference other REE) can migrate from the subducted slab to the mantle wedge. Thus, variable Nd-isotopic ratios in island arc magmas (e.g. Sunda, Lesser Antillas) may not he a primary feature of the mantle wedge but a consequence of the release of Nd from the subducted slab.

Jan 1, 1987

By Sun Yubo

A basic method for designing reasonable jig cycles for movable-screen jigs is presented in this paper. The reliability and effectiveness of the designed jig cycle was verified with tests performed on an artificial mixed material. An iron ore (12 - 100 mm) from Huashugo Iron Mine, Jiuquan Iron and Steel Company, was treated in the TJD-75 movable-screen jig using the designed jig cycle. A good result was achieved. The procedure presented here should provide a reliable technique for the design of a commercial movable-screen jig.

Jan 1, 1993

By Waijun Cheng, Guilin Xie

A microcomputer control system prototype of a Switched Reluctance drive for storage battery electric vehicle in coal mines is developed. The paper introduces the hardware components, the control strategy and the software unit. It is shown that

Jan 1, 1998

By A Cornelius, P Connor, S Fraser

Iron ore mining is a major source of export income for Australia. However with the decreasing reserves of high-grade, low-phosphorus hematite ore, there is mounting pressure to provide consistent mineralogical ore grade. Enhanced 3D characterisation and modelling are crucial to respond to these exigent requirements. To tackle this problem a revolutionary mine-based, imaging system (based on Visible Near Infrared û Short Wave Infrared reflectance spectroscopy û VNIR-SWIR) has been developed. This innovative, CSIRO-built prototype produces mineralogical maps that will have a major impact on ore grade characterisation. Australian iron ore companies will benefit immensely by pioneering this emerging and unique mining technology. The significance of VNIR-SWIR reflectance spectroscopy is well demonstrated with field portable spectrometers and airborne hyperspectral systems. At the mine-scale level, this newly developed imaging system will allow accurate and objective mineralogical mapping of mine faces and benches with very closely spaced sampling. These spectral mineral maps will improve deposit delineation and bring accurate and objective ore grade characterisation that will minimise drilling and enhance ore recovery. This will in turn lead to cost saving and better long-term block model planning. This system will also improve safety for mine geologists in providing mineralogical information at a distance, avoiding the need for any close contact with the mine face. The mine imaging concept is a logical response to the industry need for automatic and objective tools for sustainable and future mining practices.

Jan 1, 2002

By C Fricke, R Wood, P Velletri

"In a climate characterised by an ever increasing focus on cost reduction and maximising the utilisation of existing assets and infrastructure, understanding the uncertainty associated with alternative investment and operational choices becomes paramount to minimising the risk of making an ineffective decision. To assist in this process, TSG Consulting has developed an analytic framework to capture the underlying complexity of a mineral supply chain, and then quantify the impact of the uncertainty associated with the key drivers of business productivity. The technical basis of this approach follows three distinct steps: analyse the current system and identify the major factors that drive value build detailed models that can measure the response of the system to potential changes in the factors identified quantify the sensitivity of financial and capacity forecasts to these factors.Each of the above steps draws on a different area from the field of applied analytics, namely: data analytics dynamic modelling and designed experimentation meta-modelling and optimisation.Following the three-step approach described above ensures a rigorous modelling and analysis process is executed to support strategic mine planning decisions. The approach is equally applicable to the analysis of fully integrated system supply chains (pit-to-port), the evaluation of incremental capital investments to targeted areas of a supply chain, or when considering revisions to the operating philosophy of a system in the short term. The basis of each of the three analytic steps is explored in detail in this paper. The result is the definition of a structured mechanism for a business to actively manage risk and drive productivity as a component of the strategic mine planning process.CITATION:Fricke, C, Velletri, P and Wood, R, 2014. Enhancing risk management in strategic mine planning through uncertainty analysis, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014, pp 275–280 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 24, 2014

By Nilmani M, Fountain CR

Injection of gases into slag-melt mixtures produces various zones as a result of bubble formation and disintegration within the melt. The extent of these zones depends on the type of reactor used. When compared with ferrous processes, non ferrous processes are character- ised by large bubbles formed adjacent to the tuyeres, low flowrates and shallow tuyere sub- mergence. These features can result in a greater proportion of reaction occurring above the bath, more refractory wear and tuyere blockage with more splashing. The large bubble zone adjacent to the tuyeres has been investigated using the tech- niques of physical modelling, mathematical modelling and plant trials. Large bubble form- ation in physical models was recorded using a high speed camera and a rapid response pressure transducer coupled to an oscilloscope and data recorder. It was found that the bubble volume (Vb) could be correlated at low flowrates using the single bubble model Vb = 1.378 Q6/5 g-3/5 Deviations from this correlation occurred with increasing gas jet momentum. Plant trials were carried out on a copper converter at Mount Isa Mines during five different charges. Pressure measurements were made through the tuyeres during the slag blow and commencement of the copper blow. The power spectrum density showed that the dominant pulse amplitude occurred at a frequency of approximately 3 pulses/sec. Plant data from this and other converters were correlated using the same relationship as for physical modelling. De- viations occurred due to the state of the re- fractory, bath composition or bath circulation effects.

Jan 1, 1984

By D Stephenson, N R. Steward

“TerraFlowingTM” is a dewatering process that addresses both the value proposition of Tailings as a Resource™, and the safe storage of tailings. “TerraFlowingTM” incorporates two stages of cyclone dewatering followed by centrifugation of the final dilute tailings stream. In this process three dewatered tailings streams are produced; a primary cyclone underflow, a secondary cyclone underflow and a centrifuge pulp. These three streams can be combined, or used, in various configurations to achieve different outcomes. The ability to vary the cyclone and centrifuge operations and configuration enables this process to deal with tailings feed variations in particle size distribution and mineralogy and deliver consistency, or design variations, in particle size distribution, tailings solids concentrations and recoveries. Water recovery can be up to 85% of the total water in the tailings with a stackable final tailings product achieved if the three tailings streams are combined in the maximum solids concentration configuration. The primary cyclone can be operated to deliver a particle size distribution suitable for tailings storage facility embankment construction or alternatives such as concrete structures or shotcrete for support. The secondary cyclone underflow and centrifuge pulp is suitable for beaching deposition within the tailings storage facility.

Jul 1, 2021

By Rixon LK, Walton KP

Evidence will be presented to show that borescope inspection of mine roofs is one of the most useful techniques available for stability assessments. ACIRL currently has four borescopes, comprising two fibre-optic units of 2.7 m and 4.5 m length and two optical rod units (introscopes) 6 m and 8 m in length. (The 8 m unit is not yet fully operational because of modifications needed to meet safety regulations). Using the fibre-optic units, photographs of hole walls or ends can be taken to record features. Roof lithology and crack patterns can be observed in roof holes from 25 - 60 mm in diameter. Several crack parameters are useful: type, location in the roof with respect to height and lithological boundaries, presence of individuals or zones containing crack clusters and the estimated amount of dilation. These data are readily computer- plotted to form "borescope logs". Provided that the holes remain open, a hole or group of holes can be re-surveyed at intervals to monitor crack development across or along a roadway, for example with respect to an advancing blind-ended roadway face.

Jan 1, 1986

By P Mikula, B Darlington, J Graham, P Young

In underground mines experiencing dynamic events, there is an ever-present challenge to design and maintain a capable ground support system. One key component of ground support systems is surface support, which serves the essential roles of retaining failed rock and transferring forces generated by surface displacement to rock bolts or other support elements. Observations underground show that in many instances, standard mesh panels alone do not provide sufficient dynamic support to retain substantial bulking failures imposing displacement onto mesh, and in such cases Mesh straps and W-straps may be employed. Determining the performance of surface support elements proves to be difficult, with a multitude of variables at play in the underground environment. Quite comprehensive work has been completed on laboratory testing of surface support systems; however, very little work has been conducted on in situ dynamic testing of Mesh straps and W-straps. In 2019 in Western Area’s Flying Fox Mine, in situ dynamic testing was conducted on a series of Mesh straps and W-straps using Sandvik’s in situ Dynamic Test Rig (DTR). The testing regime applied impact energies from 5.1 to 15.3 kJ to Mesh straps and W-straps. The performance of the straps that did not fail was a maximum absorbed energy of 9.3 kJ and 14.2 kJ for the Mesh straps and W-straps respectively. The testing successfully demonstrated the ability of Sandvik’s DTR to test not only rock bolts, but also surface support elements, creating new testing and research possibilities. The testing also provided important design guidance data that is not practicable to obtain using laboratory dynamic testing facilities.

Nov 29, 2022

By Grimstone LR, Leach JHJ

An analytical technique is described to identify areas of structural disturbance to coal and interseam strata in coal measures. It is based on exploration borehole data which records seam intersections and interseam lithologies. Computerised data bases have been developed to allow processing of large quantities of borehole records. The case study discussed is located in a tectonic setting dominated by thrust faulting. It provides a mechanism for the identification of low angle and bedding plane faults. In addition it allows the preparation of plans showing the areal distribution of the thrust sheets in the statigraphic section throughout the mine prospect. The technique requires the identification of normal undisturbed depositional thickness of coal seams and interseams to be determined. This is done for coal by the identification of coal ply distribution over the area. For interseam lithologies it is based on sedimentological modelling of lithology distributions, related back to the original depositional environments. Variations from the expected values are interpreted as structural Deformations.

Jan 1, 1986