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By R Wolff

One critical factor in open pit mining projects is the estimation of the recoverable reserves. The reason for this is that at the valuation stage there is a lack of information about future metal prices and production costs. Consequently, the estimation of the recoverable reserves needs to be done based on a fixed break-even cut-off grade (BECG), in which fixed expected metal prices and production costs are assumed throughout the operating life of the mine (OLM). In this paper, an alternative technique for estimating the recoverable reserves of an open pit mining project is presented and explained in detail. The main characteristic of this technique is that it estimates the recoverable reserves of the project using mining costs as reference: this is done due to the fact that mining costs are easier to model than metal prices. Another important characteristic of this technique is that it uses the uncertainty of the geology of the orebody, given by simulations of the deposit, to make final strategic decisions, such as the selection of the operating life of the mine and the optimal production rate, which minimise the risk of not achieving future production targets while maximising the upside potential of future rewards. As it will be shown, the final outcome of the proposed technique is the generation of a robust open pit design, that include cutbacks and ultimate pit limits, called the marginal open pit mine design (MOPMD). One characteristic of the MOPMD is that, at each production period, it will be characterised by their respective geological uncertainty, given as probability distributions of ore, waste and metal quantities, and by marginal economical project indicators, such as cut-off grades and metal prices, among others. The details follow in the paper.

Jan 1, 2006

The Yabulu refinery of Queensland Nickel Pty Lld near Townsville now imports more than three million wet tonnes per year of nickel laterite ore from New Caledonia and Indonesia, making it the largest importer of any commodity in Australia. The project has illustrated that importing untreated bulk ore and re-exporting high value products makes good economic sense for the company and the nation.The economics of this exercise were considerably enhanced in 1994 by changing the project's principal product from nickel-oxide sinter to refined high-purity nickel metal. It is one of the few operations in the world where nickel ore is transformed to nickel metal at a single site.Several novel technological processes were developed at Yabulu and incorporated into the refinery to allow this product transition to occur. By utilising internally developed technology the new processes were installed at a capital cost of less than $10 million. It is unique for a large nickel producer to change completely the quality of its entire product range many years after the plant was constructed and considerable attention to marketing the new products has been required.The changes have meant that the project is no longer limited to selling lower-value oxide sinter to a relatively small number of large stainless steel mills. In the past year sales of the new high purity nickel metal products have expanded to include a broad range of international customers in the special alloy, foundry and chemical industries.

Jan 1, 1995

By S Munn

Today, it can be said that the majority of mines utilise communications equipment in one form or another. Either for communications between staff making their day-to-day operations more efficient, or for emergency communications, as well as linking computer based mine management systems, and providing remote control over complex mobile and fixed machinery. With the advances in technology now available, we are moving into the next generation of mine communications equipment, using digital communications in the underground mine environment. It is a proven fact that an efficient underground mine communications system can help maximise production, by providing major gains in areas such as equipment and manpower utilisation, staff and vehicle tracking, reaction times to break downs and emergencies. In this paper we will describe some of the facilities that are currently available, as well as what will soon be available to mining and tunnelling companies around the world.

Jan 1, 1999

Nine case studies are presented to illustrate how risks can be, minimised or quantified during pit optimisation, utilising Whittle Four-D software. Each case study covers a specific problem that has been encountered from a wide variety of pit optimisations. Case A: Maximising profits when the tenement owner is paid a royalty on tonnes processed. Case B: Allocating product prices, rather than a single commodity price during optimisation. Case C: Quantifying processing costs that are affected by penalty elements in the ore. Case D: Exploration expenditures below current pits can be quantified through the use of simulation techniques. Case E: Alternative strategies can be quantified when pits are restricted by tenement boundaries. Case F: Relocation of mine infrastructure that requires large capital expenditures, can be simulated by allocating costs to an area during optimisation. Case G: Evaluating alternative corporate strategies during pit optimisation. Case H: Sensitivity analysis for price, processing cost and mining cost. Case I: Quantifying the advantages of using additional mining capacity during the early periods of mining.

Jan 1, 1994

This paper reviews recent advances in geophysical tools for mineral exploration. It does not restrict comments to methods which are usually applied in the tectonically active belt surrounding the Pacific Ocean, where geophysics has often been secondary to geological prospecting (eg visual recognition of surface alteration) and drainage geochemistry; but considers geophysical tools applied to a broader range of both deposits and terrains. For example, the subdued topography of much of Australia and Canada has lent itself to the development and extensive application of airborne methods. In Australia, deep weathering and transported cover have necessitated the use of geophysical methods to not only detect anomalies but also to map and understand basement geology. This same weathering has caused specific problems, particularly for electrical methods, but recent improvements in instrumentation, processing and visualisation have largely overcome them. A great deal of geophysical data is now being collected by government agencies, often from the air, and made readily available to explorers. In several Australian states it is free, often on line, and in almost all cases it is relatively cheap. These regional data sets are often augmented by more detailed local surveys in areas of interest. Although æanomaliesÆ are still important much more is being done with the high quality data which is now available The results are used for geological mapping, to test geological hypotheses, to construct detailed 3D geological models and, together with fluid flow modeling, to predict optimum locations for mineralisation.

Jan 1, 2004

By Sen A. K

The Chiria Iron Ore deposit falls within the well-known Horse-shoe-shaped Singhbhum-Bonai-Keonjhar belt in India, where most of the deposits supplying ore to various steel works of Steel Authority of India Limited (SAIL) and Tata Iron and Steel Company (TISCO) are located. With an estimated reserve of about 2000 million tonnes of ore (at 55 per cent Fe cut-off) spread over four contiguous blocks, it is the largest iron ore deposit in India and one of the largest in world. The present study is confined to only one of the four blocks of Chiria viz North Block, comprising an area of 2.11 km2. `Corporate Plan 2005' of SAIL envisages development of a large open cast mine at Chiria to meet its enhanced requirement of iron ore by 2001-02 AD.

Jan 1, 1995

By C Sellens, L D. Fabbro, S Vink

The Fitzroy River Aqua-Eco Health Project is a collaborative research project between the Central Queensland University, the University of Queensland and BMA. It is designed to assess the aquatic ecology and health of the streams within the Fitzroy catchment located adjacent to mine sites. The universities are conducting an independent sampling program expected to yield the most comprehensive monitoring to date. The project design incorporates in situ testing of water quality variables including temperature, dissolved oxygen, conductivity, oxidation reduction potential, pH and turbidity. Water and sediment chemistry incorporate testing for sulfate, suspended solids, nutrients and metals. This sampling is complemented by quantifying changes in the abundance and diversity of a wide range of biota, including microbial, macro invertebrates and fish.This paper will detail the program and highlight some of the particular difficulties in conducting this type of research in ephemeral stream systems. Case study examples will be used to illustrate insights being gained from the program. CITATION:Fabbro, L D, Vink, S and Sellens, C, 2013. The Fitzroy Aqua-Eco Health Project, in Proceedings Water in Mining 2013, pp 117-120 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

By R Nicholson, N D. Cox, N W. A Lambert

"This paper reports on the long-term operation of a particle density meter (PDM) at the Bloomfield coal handling and preparation plant (CHPP). This unit has been operating continuously for over three years, providing real-time data to the operators to allow the monitoring of flotation circuit performance. PDM outputs include slurry density, solids concentration on both mass and volumetric basis, and particle density. Knowing the average particle density of a stream allows for the optimisation of the process in real-time.The calibration of the solids concentration measurement device proved very difficult as the factory calibration techniques and existing laboratory analysis did not give accurate or reliable results. The solids concentration device had to be re-engineered and a new calibration method developed that gave accurate and repeatable results. Independent verification of samples taken from the PDM was undertaken as part of the trial process.The operational reliability of the PDM was a major point of investigation. The initial installation of the unit revealed issues with large, misplaced material of up to 20 mm periodically entering the unit, leading to feed blockages. The presence of these misplaced, oversized particles in the flotation circuit was resolved by installing innovative automatic back flush systems on the PDM.From a plant perspective the PDM has been an invaluable instrument that has enabled irregularities in the flotation circuit performance to be identified, which sampling had not and could not readily identify. This was achieved by close monitoring of real-time tailings composition on a minute by minute basis over short and extended periods. Variations in the tailings stream with respect to particle density and solids concentration were traced back to other issues in the plant. In addition, the PDM has allowed cell optimisation with respect to reagent dose rate to be improved. The PDM with real-time feedback can negate the need for large sampling campaigns and analysis during plant optimisation programs.Citation:Lambert, N, Cox, N and Nicholson, R, 2016. Particle Density Meter, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 245–250 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By S O. Hille

Modern remote mining operations in Australia are more commonly trending towards fly-in/fly-out (FIFO) sites. This trend is driven by numerous factors including increased business centralisation, reduction in operating costs, and a desire to live in coastal cities that offer closer family networks and a greater diversity of facilities. Consequently, the resource development industry has had to adapt. When WMCÆs Mount Keith Nickel Operation commenced operations in 1994, it was developed as FIFO for its entire workforce. Since then, there have been several permutations of rosters within a 21 day compressed work cycle including the 14/7 cycle. This paper discusses a case study of the change in management process to the 9/5 work cycle focusing on minimising fatigue in the workplace. It includes the discussion of the business case, employee reaction and the practical application. The impact of the best practice change after 18 months is discussed.

Jan 1, 2002

By A Vakili, F Harvey, H Greaves

Mine seismicity is one of the most difficult geotechnical risks to manage in seismically active mines. There are currently some established empirical and statistical methods that provide quantitative measures for seismic hazard assessment in operating mines. However, these methods are mostly suitable for quantifying the current or historical seismic hazard and often cannot be directly used to forecast the future hazards. Numerical modelling is the only analytical tool that can capture the level of complexities required for a meaningful analysis of mine seismicity and therefore to facilitate a reliable forecast of future hazards. However, there is currently no widely accepted and established guideline and methodology for analysing and forecasting mine seismicity using numerical modelling. This paper first provides a background on previous published studies on this subject and then outlines the key aspects that can affect the reliability of the forecasting for mine seismicity. These aspects include a) processing of historical seismic data, b) selection of suitable numerical modelling approach, c) Post-processing and interpretation of the model outputs. A case study is then presented for the Gwalia Deeps Mine where a new framework was developed to forecast future mine seismicity. High-quality seismic data for a period of five years was used for back-analysis and comparisons with the numerical modelling outputs. After development of the method, the future seismicity was forecast for the next 12 months and the actual seismicity was monitored against the forecast during this period. Results of this study shows promising potential for the proposed framework to be applied more routinely and at other mine sites. However, more validations are required at Gwalia Deeps mine as the mine proceeds to deeper levels. In addition, the method needs more improvements and should be tested and validated at other mining operations before it can be established as a proven method. CITATION:Vakili, A, Harvey, F and Greaves, H, 2018. Forecasting mine seismicity – towards a more established methodology, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 207–222 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By B Hou

The Eucla Basin in southern Australia is emerging as an important global source of zircon from heavy mineral sands. Understanding the geological evolution of the basin and movement of heavy minerals down peripheral paleovalleys and along paleocoastlines is essential to effectively refine exploration strategies for heavy minerals in the basin. Integration of geoscientific datasets in a Geographic Information System (GIS) environment has proved to be effective in reconstructing depositional environments along the Cenozoic basin margin and in tracing the buried paleorivers that once drained broad areas of the Archean-Paleoproterozoic Yilgarn and Gawler cratons, the dominantly Mesoproterozoic Musgrave and Albany-Fraser Provinces, and the Neoproterozoic-Early Paleozoic Officer Basin. Sea level highstands during the late Middle Eocene (39 - 36 Ma) are associated with formation of the Ooldea coastal barrier complex and the zircon-rich heavy mineral deposits at Jacinth, Ambrosia and Tripitaka. More extensive transgression during the Late Eocene (36 - 34 Ma) built the complex Barton shorelines that host the Cyclone deposit and the extensive ilmenite-dominated occurrences of the Barton West prospect. Multi-generation reworking of the source sands is indicated by the high proportion of deposits that are zircon-rich relative to titanium minerals. The age distribution of zircon grains in heavy mineral concentrates from the Ooldea and Barton barrier systems points to the Musgrave Province as the predominant ultimate zircon source. Paleorivers discharging along the northern basin margin presumably carried a sediment load that was then redistributed by easterly longshore drift to build the extensive coastal sand deposits along the northern and eastern basin margin. The south-eastern extension of these deposits was reworked during Miocene-Pliocene (15 - 2 Ma) times into a series of regressive strandlines that show angular discordance with the Eocene coastlines. This discordance is consistent with evidence for long-wavelength tilting of the Australian continent from Middle Miocene times, as the continent drifted toward a dynamic topographic low induced by convective mantle processes associated with the South East Asia subduction systems. The Dromedary and Gulliver’s deposits probably formed at this time. Ongoing research is focused on the geological features of the basin that influence heavy mineral transport, concentration and preservation, and the processes leading to deposits with high zircon content.

Oct 5, 2011

By A C. Robertson

World urban expansion puts constraints on the available land surface area of our major cities both for accommodating people as well as providing infrastructure and services whilst at the same time attempting to preserve the remaining natural environment. Whilst consideration is often given to underground planning for private and public transport infrastructure, the author is of the opinion that the current lack of underground planning of our cities that are suitable for underground development will have major long implications when finally the need for underground space planning is critical and ultimately recognised. This paper identifies the need for our city planners to integrate surface planning and underground planning as a ‘total planning solution’ where the city plan incorporates the elements of underground space planning as identified in this paper. Investigations by the author reveal that there are very few cities in the world that actually incorporate underground space planning in their city plans. The author uses the City of Brisbane as a case study for the potential introduction of underground space planning as part of the city plan. Despite efforts by the author to include the planning concept of underground commercial development in the latest Brisbane City Plan 2014 as well as four underground space workshops in Brisbane over the past 20 year through the Australasian Tunnelling Society (ATS), underground space planning for the City of Brisbane, apart from infrastructure projects, is not considered of significance to the City of Brisbane.CITATION:Robertson, A C, 2014. Commercial underground space – planned development for the future, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 513–518 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By L Smith, R Beckie

Controls on environmental loading from acid rock drainage (ARD) are not well understood in waste rock material. In particular, relationships between subsurface flow and the timing, duration, and intensity of leaching of metals and acidity from waste rock dumps remain ill defined. This study investigates field-scale relationships between subsurface flow processes and geochemical processes in unsaturated waste rock. A 12-metre tall, unsaturated waste rock pile, constructed in 1994, was deconstructed and sampled at Key Lake, Saskatchewan, Canada, during the summer of 2000. A detailed sampling methodology was developed to characterise physical and chemical properties of waste rock material within the waste rock pile. Physical properties were characterised by measuring soil-water suction, volumetric water content, and grain-size distribution at 60 random locations within the pile and grain-size distribution at 20 grid locations within the pile. Attempts to develop a field-based soil water characteristic curve from physical field-data failed due to spatial variability and hysteresis of waste rock properties. As a result, grain-size distribution was used as a relative measure of subsurface flow. Paste pH, pore-water geochemistry, mineralogy, and water-soluble extraction results were used to characterise geochemical processes and sulfide oxidation at each of the 20 grid locations. Geochemical characterisation results demonstrated the preferential weathering of marcasite relative to pyrite and chalcopyrite. Dolomite was the main buffering carbonate mineral. Gyspum, jarosite and iron oxyhydroxides were the main secondary minerals. Pore-waters contained up to 800, 11.7, and 6 mMolar (78 000, 690, 1400 mg/L, respectively) of sulfate, nickel, and uranium, respectively, suggesting significant weathering has occurred. Measures of weathering indicators show no discernable correlation with grain-size distribution nor do they show any spatial relationship within the sampled grid. Reasons for this may include limited duration of waste rock exposure to weathering and development of fluid flow-paths, and limitations of characterisation methods used. Indeed, six years may not be long enough for weathering patterns to develop due to fluid flow-paths in this unsaturated waste rock pile.

Jan 1, 2003

By R Young

Independent Project Analysis (IPA) is in the business of benchmarking the performance of capital projects on behalf of owner companies in the processing and extractive industries. IPA assesses between 500 and 800 projects each year. The projects are conducted globally and range in size from about $1 million to over $30 billion. Using the data, we are able to benchmark the performance of Australian projects against the rest of the world. This presentation focuses on the performance of large (greater than $100 million) projects that involve chemical or thermal processing.We regularly hear calls for more processing to be conducted in Australia but on the other hand industry leaders are concerned about the poor success rate of solids processing projects in Australia. Data gathered by IPA indicates that there is good reason for the concern. Out of a sample of 31 large processing projects conducted in Australia, 23, or 74 percent, were classed as failures. This performance is significantly worse than for similar projects in other parts of the world. The presentation analyses why the performance is worse and demonstrates that many of the reasons behind the failures were manageable by the project team. Furthermore, members of the project teams on at least half the failed projects knew that the projects were on a path to failure before the project was authorised but could not be heard.The presentation discusses how large projects that involve process design and, in many cases, new technology, need to be set up for success. *This is an abstract only. No paper was prepared for this abstract.*

Aug 8, 2011

By M E. Webb

Safety is a key value in most leading mining companies. Despite years of effort, and significant expense in ‘programs’, operating sites seem to have been left with no real improvement in either the elimination of fatalities or sustained reduction in injuries.Safety systems and processes have grown and evolved, often to the point where they have become overly complicated and marginally useful.MMG Limited, following the consolidation of its Australian operations under a single management structure, undertook a program to effect real and sustained change in its approach to managing safety. The program aimed at improving safety by better engaging its workforce and by making safety processes simple, useful and effective. It defined the role of the supervisor in creating safe work, the role of the people doing work and the role of safe work methods.A safety diagnostic tool was developed to assess site against safety-critical mindsets, behaviours, cultures and systems. The outcome of the diagnostic is considered by the organisation to be the true lead indicator of safety performance.While still a work-in-progress, the program at the Australian Operations of MMG Limited shows that challenging common paradigms in safety management can create real change in safety performance.CITATION:Webb, M E, 2016. Making safety simple, useful and effective, in Proceedings International Mine Management Conference, pp 217-223 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 22, 2016

By Glastonbury J. R

The kinetics of the direct chlorination of, zircon in the presence of carbon was studied at temperatures between 9000C and 12000 C. From the experimental data it is prop- osed that the most likely mechanism for metal oxide (MeO2) chlorination is as follows: At I Surfaceon zMeO2+ZMeCl - MeOC12 (1) At Carbon MeOC12+C+Cl MeC14+CO (2) Surface It.is envisaged that this type of mechan- ism would occur for both the zirconium and, silicon. constituents of the ore. In the above mechanism; the surface re- actions appear to be fast and not rate controll- ing. In a carbon surface deficient bed the diff- usion of oxychloride intermediate through the boundary layer to the carbon surface becomes the rate controlling step. In a zircon surface deficient bed the diffusion of oxychloride away from the zircon surface controls the reaction. This postulated mechanism can be used to ex-, plain the observed experimental effects.

Jan 1, 1973

By Collins DN, Hollick CT

Conventional processing of heavy mineral deposits containing radioactive rare earth minerals such as monazite and xenotime may cause industrial hygiene problems through atmospheric dust and contamination of product concentrates. An alternative procedure has been developed in which such minerals are removed from bulk heavy mineral concentrates by flotation with little loss of other economic minerals. With fine ores, recoveries of over 95% have been achieved and with coarse ores over 80%,in both cases at high grade. Several flotation regimes have proven effective. The potential for generation of radioactive dust or product contamination is subsequent processing -is correspondingly reduced.

Jan 1, 1990

By Dixon D. R, Sparrow G. J

Pressure leach liquors from the pressure oxidation of a bulk flotation concentrate prepared from a complex Cu-Pb-Zn sulphide ore were treated to remove iron, either by pressure oxidation (the Hematite process) or with particles of magnetite (the Magnetite process), followed by cementation of various metals with zinc dust to obtain a purified solution from which zinc was electrowon. Satisfactory iron removal was achieved by both processes after neutralisation to pH 4.5 or 5.5. Pressure oxidation of the liquor at 200¦C and 690 kPa oxygen overpressure, conditions similar to those of the Hematite process used in the zinc industry, resulted in the precipitation of the iron as hematite. With the Magnetite process, an iron hydroxide was precipitated onto magnetite at atmospheric pressure and ambient temperature and removed by a magnetic separation step. The performances of both these processes for the removal of iron are compared. It is concluded that the Magnetite process offers considerable cost savings. Other impurities, in particular arsenic, were also removed with the iron in both processes. Cementation at pH 5.2 and 85-90 ¦C with 3.5 g/L zinc dust reduced the levels of copper, cadmium, and nickel to a satisfactory level and subsequent electrolysis in a laboratory cell gave an acceptable deposit of zinc.

Jan 1, 1989

By Williams P

The assumptions made in conventional (Terzaghi) consolidation theory are not met in a tailings deposit. Finite or large strain consolidation theory must be employed. The paper describes such a consolidation model and its application to the design of tailings impoundments, water management systems, and long term rehabilitation.

Jan 1, 1990

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