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Just as geophysics, in the form of 3D seismic and wireline logging, plays a key role in petroleum reservoir management, so too will geophysics play an important role in mining of coal, metals, and minerals in the 21 st century. The commercial and social imperatives driving greater use of geophysics are reduced costs, increased revenues, and enhanced safety. In short, superior utilisation of capital and management of risks. In relatively undeformed sedimentary environments it is possible to adapt petroleum-style 3D reflection seismic to image mines. This has been demonstrated most impressively in the Witwatersrand. Anglo-American, for example, completed a $1 million 3D seismic survey at Western Deeps in order to site a new $300 million shaft with confidence. Likewise, 3D seismic has gained rapid acceptance at Australian coal mines in recent years. Encouraged by these successes, metalliferous mining companies are supporting research in Canada and Australia, as well as South Africa, to adapt 3D seismic for more highly structured, metamorphic terranes. Because the mining industry is far more diverse than the petroleum industry in terms of commodities and geological environments, 3D seismic is not always cost-effective. A plethora of other geophysical techniques can be applied, many of which are employed in mineral exploration. Mine applications of geophysics differ from traditional exploration applications in two main ways: time scales and length scales are shorter, and boreholes are more plentiful. Borehole geophysical techniques therefore play a more significant role, both for logging and imaging. Logging systems detail the variations of in situ physical properties down the borehole at scales measured in centimetres, while geophysical imaging techniques can map features located tens or even hundreds of metres from the sensors. While geologists tend to think of boreholes in terms of chips and core, geophysicists perceive them first and foremost as access paths for instruments. Borehole logging has been employed at iron and coal mines for decades, mainly to accurately define ore boundaries in delineation holes. In base metal mines, Outokumpu implemented logging widely for orebody delineation in percussion holes in the 1980s. The benefit was a direct cost-saving, arising from substitution of core drilling with percussion drilling plus borehole logging. The practice has since spread to other companies. INCO, for example, defines nickel boundaries in blast holes at Sudbury using conductivity logs. The benefits are in the form of reduced dilution and enhanced ore recovery, flowing from a more accurate mine model. Density, natural gamma radiation, magnetic susceptibility, and conductivity are the principal metalliferous mine logging parameters because they can be recorded in both dry and water-filled holes. Sonic velocity is the premier geotechnical logging parameter, given its sensitivity to rock strength, stress, porosity, and degree of fracturing. Sonic is recorded routinely in exploration and geotechnical holes at coal mines. With the advent of slimline dipmeter, full waveform sonic, and optical and acoustic scanner tools, the role of borehole logging in geotechnical evaluations is expanding. Monitoring of strain and micro-seismic activity enhances safety during mine production. While qualitative interpretation of logs is adequate for stratigraphic identification or definition of boundaries, a wealth of quantitative information, eg density, can be derived from properly calibrated, repeatable geophysical logs. Moreover, geophysical logs can sometimes serve as surrogates for geochemical assays, and not only for magnetite and uranium. At OutokumpuÆs Kemi chromite mine, for example, gamma-gamma logging provides the basis for grade control. By reducing reliance on assaying, three benefits can be realised: reduced reliance on core drilling; lower core handling and assaying costs; and shorter turn-around times. Conventional downhole EM and borehole magnetics are used for near-mine exploration, and for ground sterilisation. Inco has enjoyed considerable success with borehole UTEM in the Sudbury Basin, for example, and Geopeko has applied three-component borehole magnetics successfully in the Tennant Creek area. Electrical techniques such as applied potential and magnetometric resistivity (MMR) are also finding application at mines. For higher resolution, borehole seismic, radio imaging, and radar have been invoked, with varying degrees of success, to delineate orebodies and map structures, or to geotechnically characterise the rock mass and identify hazards. Success mapping nickel sulphide shoots with borehole radar has been reported by WMC at Kambalda. There are no universal geophysical panaceas, and each mine imposes different geological, logistical, and economic constraints. Geophysics will not always be cost-effective. However, the greatest single impediment to expanded use of geophysics at mines has been the low level of awareness of geophysics on the part of most mine geologists, engineers, and managers and, equally, the limited understanding of mine geology and engineering exhibited by the majority of geophysicists. This myopia will be remembered as a 20th century affliction! Blue Sky areas for mine geophysics in the next ten years include integration of geophysical data acquisition with drilling, enhanced grade estimation and rock mass characterisation, and the incorporation of geophysical information into mine models using geostatistical techniques. All these advances will be predicated on an expansion of petrophysical knowledge.

Jan 1, 2000

By D Hunter, N Cusworth, J Miller

"Recent project failures have called into question the use and relevance of benchmarking and independent reviews, forcing a rethink of traditional processes and procedures.With cost estimates and schedules dramatically varying from lows seen around the global financial crisis to peaks experienced in the recent mining boom, benchmarking has ranged between essential and misleading.Profound shifts are now underway in future project delivery strategies as the market moves away from cost-plus engineering, procurement and construction management. The current trends in project implementation are to utilise more lump-sum design and construct or fixed-price supply and construct contracts. This trend will remove transparency in detailed cost information by reducing the sources and clarity of cost data.Independent peer reviews (IPRs) of studies and investment recommendations performed over the last decade have both failed to prevent flawed or deficient projects from proceeding to approval and funding, and been successful in ensuring that owners did not proceed with doomed investments.In recent times, it has been recognised by some owners, contractors and engineers that traditional benchmarking checks or IPRs, or a combination of both, will not necessarily produce reliable assessments of study conclusions and of the forecasts of project outcomes. To be of value, the benchmarking process now also needs to recognise the highly volatile responses from the engineering and construction industry to the current and future markets for their services.Similarly, reviewers who draw upon benchmarks of past project experiences on an understanding of the things that shaped and influenced their outcomes need to be more aware of how a future dynamic market may impact the outcome of the projects and raise warning flags accordingly.With the commodity cycle currently approaching what is hoped is its bottom, ensuring that benchmarking and independent reviews evolve into reliable, transparent and worthwhile processes becomes even more important. This can only be achieved with more transparent and analytical benchmarking and business-orientated reviews that both recognise and calculate the impacts of dynamic markets on project implementation.CITATION:Cusworth, N, Hunter, D and Miller, J, 2016. The role of benchmarking and independent reviews, in Proceedings Project Evaluation 2016, pp 249–259 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 8, 2016

By A Scott, I Onederra

Most iron ores occur in mine benches as complex mixtures of lithologies and ore types. This significantly complicates their characterisation for both blast design and fragmentation modelling. A great deal of technical and research effort has been applied to the development of models to predict fragmentation from rock blasting. A number of quite useful engineering models are currently available to blasting engineers and consultants, and more sophisticated approaches using mechanistic descriptions of rock breakage continue to be developed and applied by researchers and explosives companies.The engineering or empirical models that are in more general use within the industry, such as the Kuz-Ram model, require appropriate data if they are to generate useful fragmentation predictions. Some of these models have reached significant sophistication and have made very useful contributions to both routine blasting operations and the exploration of new blasting paradigms. However, these models struggle to adequately deal with rock that is as complex as iron ore. This paper reviews the characteristics of the most successful blast fragmentation models available to the industry and discusses approaches to the derivation of suitable rock mass properties to adequately describe blast fragmentation in a range of iron ores.CITATION:Scott, A and Onederra, I, 2015. Characterising the blasting properties of iron ore, in Proceedings Iron Ore 2015, pp 481–490 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

Banks' focus in using cash flow methods can differ markedly from that of equity investors. This paper attempts to explain and describe bankers' approach by: ò outlining the fundamental difference between banks' and investors' risk / return profiles. ò describing lenders' consequent use of cash flow methods in mineral valuation. areas. explaining lenders' specific treatment of key risk Fundamental to understanding banks' appraisal of mineral projects is the appreciation that lenders have a basically different risk profile and outlook from those familiar to equity investors. Lenders do not normally participate in any project upside. The economics of lending dictate that banks can only accommodate a low probability of loan default and consequently banks' principal focus in mineral ""valuation"" is ensuring an acceptably comfortable probability of debt repayment. A simple conceptual explanation of lenders' risk / return position is outlined.

Jan 1, 1994

By Thompson J

A programme of testing and evaluation has been in progress at Isa Mine for the last four years with the objectives of rationalising ground support practices, improving installation quality and increasing productivity of ground support functions.Numerous innovations have been successfully implemented. These include the introduction of swellex rockbolts as the major form of temporary support, the use of splitset rockbolts as the primary means of support for the hangingwalls of cut and fill stopes and the introduction of dowels with pumped cement for general long term support.The installation of swellex bolts has been successfully mechanised throughout the mine using Tamrock automatic rockbolters and Atlas Copco BUK 11R drilling rigs modified for this purpose.

Jan 1, 1985

By Ibrahim AR

The experimental phosphate mine of abu Tartur has been recently placed into production. Some problems'have been encountered in maintai- ning grade control due to the differences between early block estimates and actual produ- ction grade. An area of 100 km2 is evaluated by using four methods of evaluation , namely polygonal, inverse distance , inverse distance squared and geostatistical methods. The results of calculations are compared statistically with the control values of grade and thickness. The comparison showed that the. kriging technique gave better estimations for the relative ore reserved, while for grades or thickness any of these techniques except the polygonal can be Used.

Jan 1, 1986

By Y L. Ma, Y Yang, M Chen, W Bruckard

To improve the understanding of the reactions and mechanisms occurring during the leaching of sulfide ores at high temperatures a range of advanced characterisation and sensing tools have been combined to provide a sophisticated and powerful methodology to examine sulfide leaching systems. These include advanced electrochemical methods, surface chemistry and materials characterisation techniques such as synchrotron X-Ray Absorption Spectroscopy (XAS), X-Ray Photoelectron Spectroscopy (XPS), Scanning Electrochemical Microscopy (SECM), and in situ X-ray diffraction (XRD), together with new robust solid state chemical sensors for in situ real time monitoring of key aqueous chemical parameters. The methodology was employed to investigate various sulfide mineral leaching processes. For example, oxidation of arsenopyrite at elevated temperature involves complicated multiple reactions and the process is strongly influenced by the solution conditions, component speciation and mineralogy. The methodology was used to study this system both ex situ and in situ to gain a detailed understanding of the complex chemical reaction mechanisms operating. These mechanisms are discussed in terms of the observed leaching efficiency. The application of this methodology enables complex sulfide leaching systems to be understood more fully such that process efficiency can be improved.

Aug 24, 2022

By R Shelton

The Big Wainihinihi River and tunnel are located on the western side of the Southern Alps of New Zealand within the active Alpine Fault zone, which marks the boundary between the Pacific and Australian Tectonic Plates. The tunnel was built over 100 years ago to supply water for gold mining, but it now conveys water from a high-energy intake to a canal that supplies three of TrustPower’s hydro-electric power stations with a combined installed generating capacity of 10 MW. Part of the tunnel passes through an unstable 50° schist slope, which fi rst suffered a wedge failure in the 1929 Arthur’s Pass Earthquake and was reinstated in the mid-1970s for hydro generation. In 2008, TrustPower’s monitoring system showed that the wedge failure had remobilised and that urgent remediation was required.Harker Underground Construction (Harker) was awarded a design-build contract to restore the tunnel to service by tunnelling a new central section. Their geotechnical engineers, Peters and Cheung, reviewed the tunnel’s stability and proposed a new, safer tunnel alignment, deep behind the failure wedges. This work was based on their failure model, cost-benefit studies, and engineering geology completion mapping at the time of re-opening.Construction innovation was an important factor in ensuring the project’s success, as were detailed geological and geotechnical information, a robust methodology, strong client relationship and planning. To suit the varying rock conditions and restricted space, Harker combined a traditional drill-and-blast method with light-weight modular steel sets and timber supports to reduce construction costs and mitigate support risk. To make material handing easier in the tight conditions, a special electric locomotive was designed and built and blasting confi gurations were adapted to suit varying rock conditions in the highly fractured schist.The isolated site meant interesting and unexpected challenges, particularly communications and resources (both human and material). Despite that, the project was completed within budget, on schedule, and with no lost-time injuries.

Mar 8, 2011

The objectives of mining grade control are presented and examples of the techniques used in various open pit and underground mines are used to define the attributes of good grade control. Reasons are discussed for the success of various improved practices. The progressive development of grade control is presented and the balance between quantitative and qualitative data is analysed. The skills and resources required for grade control on mine sites that are using best practice are also presented. A number of problems in grade control have been solved recently however there are still issues that need to be addressed. Examination of the grade control process frequently stops after sample quality has been examined. There is much more beyond this that can now be optimised using conditional simulation models. Other future directions of mining grade control are also suggested. An extensive bibliography of published papers on grade control is included that will be maintained and updated on a website.

Jan 1, 2000

By Y V. Haarlem, P Coghill, N G. Cutmore, M Millen, I Carter

Due to the low concentration of gold, ore sorting for gold has always required measuring indirect properties, such as density or colour, to allow separation on a rock by rock basis. This only works on an ad hoc, by deposit basis and is likely to be least reliable where it is most required in low grade ores. One candidate technique, Gamma Activation Analysis (GAA) has been demonstrated to directly measure gold extremely accurately in powder samples of around 500gm and is used in the Chrysos PhotonAssay assay system. This method uses a linear accelerator (linac) to generate the X-ray radiation that activates the ore at low levels to emit a characteristic gold gamma ray that is then measured by a radiation detector. CSIRO is adapting this measurement technique to application on a belt at up to 800tph to measure pods of ore. The principal differences between measuring samples and an on-line measurement of pods are the requirement to measure coarse ore (<50mm), to measure a larger volume of ore as uniformly as possible, and to have an open-ended geometry with adequate shielding of the linac radiation source. These issues have all been addressed with measurements of coarse ore reported down to around 1ppm in sub-optimal test conditions. They have been demonstrated for <75mm particles with detectors capable of measuring a large volume geometry continuously. These are projected to allow measurements down to 0.3ppm in more optimum conditions for a 10 second measurement time period where the U/Th content of the ore is less than ~10ppm. Extensive Monte Carlo modelling has demonstrated that adequate shielding can be provided in relatively simple geometries with only 1 right angle transfer in the material handling. Steady progress is being made to reach the technical position required to trial an ore sorting system.

Nov 10, 2020

By P Mikula, R Geranmayeh, R Carlton, M Ferguson, R Whiting

The concept of using specially designed slot blasts to mine through stress abutments that intersect faults, while controlling fault-slip seismicity, has come of age at Mt Charlotte Mine. Due to the high and adverse stress field and the presence of major faults, the mine is vulnerable to significant fault-slip seismicity. As mining proceeded, advancing stress abutments around various mined areas encroached on several major subvertical faults. If the sequence formed a diminishing pillar between stope and fault, the removal or failure of that pillar daylighted the fault, and often resulted in significant fault-slip seismicity. A new strategy called ‘Tight Slot Blasting’ (TSB) was developed to restrain or dampen this style of fault-slip movement. The TSB has geometric similarities to a conventional cut-off slot used to create stress shadows, but its function is different. Its objective is to trigger and control a sudden shift of the stress state on a fault from an initial stable state, through an unstable transition, to a second stable state. A TSB firing advances a long tall narrow slot through a stressed abutment between a stope void and a nearby fault, using a rapid blast with a low swell ratio, so that the slot substantially and rapidly fills with blasted rock fragments. During the blast process, the stressed rock is rapidly removed and transformed into the fragmented rock fill in the slot. The strategy deliberately allows a fault-slip episode to manifest at a chosen time and place. The tight-packed broken rock in the slot performs an essential shock-absorbing function by controlling the slip amount and rate on the fault, while at the same time the fill becomes compacted by the movement. This controls the dissipation of fault-slip energy, and greatly reduces the seismic response in time and space. A small closure across the slot occurs, with consequent relaxation and destressing of the adjacent rock mass. Stress monitoring data shows that slot creation lowers the abutment stress in the nearby rock mass, while the newly placed fragmented rock fill acts as a shock absorber, providing considerable resistance to substantial fault-slip movement that otherwise could deliver a significant seismic event. First used in 2007, the strategy has been refined to become a routine specialised practice for management of seismically hazardous situations at Mt Charlotte, with 12 successful TSBs conducted to date. Despite mining through multiple high stress abutments, seismic reactions have not exceeded ML 2.1 with any TSB firing, all remaining below the site tolerable maximum of ML 2.3. This paper presents an overview of the strategy, and five case examples of the strategy in critical stressed areas in July 2016, Sept 2017, Dec 2017 and two in Oct 2020. The strategy has successfully managed the seismicity and is expected to remain an essential part of the seismic management plan at Mt Charlotte Mine.

Nov 29, 2022

By E A. Gunn, J Zhou

In this paper a project to develop a joint optimisation/simulation model for production planning in a mine-mill complex is presented. The system involves a mill receiving ore from a number of different locations, each with a unique mineral composition. The mill consists of several crushing and grinding circuits that function in series and parallel. Scheduling the flow of materials through the mill is complex due to constraints on throughput imposed by the millÆs design, the length of time material can be stockpiled on the surface, varying input mineral composition, and throughput targets for a range of output products.An optimisation model is used to create a set of campaigns (ore feed rates) over a given planning horizon under the assumption of deterministic mill throughput. A simulation model is used to evaluate the production plan under assumptions of stochastic machine failure and operational losses created by the need to cycle between input feeds. Campaign scheduling has two important implications for the simulation. First, during any campaign, multiple ore types may need to flow through the mill. However, the mill must be controlled to ensure that only one type of ore can be in a crusher, a grinder or a storage bin at any point in time. Second, as the mill switches from one campaign to another, the set of ores being processed may differ. Thus, the flow of ore through the equipment during a campaign changeover must be controlled to ensure that one or more of the ores from the current campaign can be completely eliminated before the ores from the new campaign are introduced.The simulation architecture employed for this project is Visual Basic for Applications (VBA) combined with MS-Excel as a user interface. A fixed step discrete event orientation is assumed as the simulation framework. A set of model constructs was built for the project with a specific Canadian milling operation in mind, but was designed to be representative of a broad class of milling operations. The constructs are implemented as class objects within the VBA structure, each with a number of properties and methods. The collection of VBA objects forms a composable modelling toolkit. These objects can be linked together by users, via MS-Excel, to represent a broad range of milling operations.

Sep 26, 2011

In the 100 years since the formation of The Australasian Institute of Mining and Metallurgy there have been significant changes in all aspects of the mining industry.A number of the changes have been driven by technical evolution or necessity, others have been driven by developments in the application of the products produced from the mining of minerals. Other changes have been driven by shifts in community values.

Jan 1, 1993

By Booth GW, Robertson IG

The Paddington Gold Mine ties within the Norseman-Wiluna greenstone belt, in the celebrated Eastern Goldfields province of the Yilgarn Block, Western Australia. Regionally, tropical to subtropical weathering has effected development of a prominent regolith and a deep lateritic profile. Detailed examination of the clay mineralogy, largely from a single drill hole which traversed the original Paddington I deposit, outlined three separate, vertically gradational assemblages, which are, in part, rock-type dependant. These include; 1. kaolinite with minur to trace quantities of sericite/illite (0-22m), 2. smectite and/or interstratified clay minerals, together with variable amounts of kaolinite, relic chlorite and illite/sericite (22-81m), and 3. chlorite and sericite (> 81m). Near surface, kaolinitic assemblages may be directly correlated with the intensity of lateritization, whereas smectite and interstratified clays from intermediate zones appear in association

Jan 1, 1989

By G Pasin, F Wirfiyata, G Khomaeni, W Valery, A Maclean, A Jankovic

The grinding circuit at PT Newmont Nusa Tenggara (PTNNT) – Batu Hijau mine consists of two SABC (semi-autogenous milling, ball milling, pebble crushing) trains, including four 20'?×?33'6? ball mills that have been lined with steel liners since the commissioning of the plant in 1999. During 2011 and 2012 an industrial trial was conducted to evaluate Poly-Met liners (a combination of rubber and steel liners). These new liners were installed in two of the ball mills (ball mills 1 and 2) and operated in parallel with ball mills 3 and 4 with steel liners.The objective of the trial was to compare the plant performance with the Poly-Met and steel ball?mill liners with regards to wear life, mill throughput, grind size and total unit costs. The trial was conducted over the entire life of the liners. The evaluation methodology implemented consisted of frequent spot sampling around the ball mill circuits, complete surveys/audits in both ball mills, and detailed analysis of process data. This paper presents the results of the industrial trial and main conclusions.CITATION:Maclean, A, Wirfiyata, F, Khomaeni, G, Jankovic, A, Pasin, G and Valery, W, 2014. Ball mill Poly-Met liner evaluation at PT Newmont Nusa Tenggara – Batu Hijau mine, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 255–262 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

The geotechnical factors controlling the design of the open pit slopes of the Pasminco Century Mine near Lawn Hill, Queensland are presented below. Pasminco Century is a stratiform shale hosted zinc deposit in the Lawn Hill Formation that is overlain in part by the Thorntonia Limestone Formation. Both the mineralisation and overburden is located within a competent rock mass such that intact rock strength and discontinuity spacing is generally sufficient to prevent large-scale slope failure by breakage through the rock mass. Rather, overall slope stability issues are dominated by the major discontinuities within the rock mass. The deposit is located in a structurally complex regime, it consists of a synclinal basin which is truncated by easterly striking normal faults through its centre and northern and southern limits and by an unconformity on its eastern and western margins. Deposit geometry and slope stability is further complicated by small-scale folding, a pattern of northeast and southeast striking subvertical faults and north easterly dipping thrust faults with their associated fault emplaced blocks of Lawn Hill Formation in the overburden. The large size of the deposit requires a staged mining approach with the excavation of both final pit walls around the external sides of each stage and interim pit walls along the internal boundaries between adjacent stages. The deposit geometry and major discontinuities control not only the final pit wall design but also interim wall location and orientation, excavation sequence and in some stages the excavation schedule. Two and three-dimensional limit equilibrium stability analyses were conducted using both deterministic and probabilistic approaches to determine appropriate pit wall design criteria and to select a suitable excavation sequence and schedule.

Jan 1, 2000

By G J. Jameson, A Agarwal

This paper is concerned with the observation and analysis of bubble clusters in a laboratory flotation cell. A device was used in which bubbles were allowed to rise in clean water containing the same frother and collector concentration as in the cell. Bubble clusters were recorded using a high speed camera and analysed using an image analyser. Dodecyl amine was employed as a collector to float silica. The effect of impeller speed on the cluster behaviour was investigated. The results were interpreted in terms of cluster diameter and shape factor. The sizes of the bubbles forming the clusters were also measured and compared to the sizes of the independent bubbles in the cell. It was found that there was an optimum impeller speed in which the cluster diameter was a maximum. Higher agitation and the consequent higher power inputs resulted in cluster break-up while lower shear rates promoted cluster formation.

Jan 1, 2005

By N Barnett, M Dello-lacovo, J Oh, S Saydam, T Pelech

In-Situ Resource Utilisation and Off-Earth mining require the application of horizontal drilling. The stability of such openings is challenging when excavating in the lunar regolith. Excavations on the Moon will encounter unconventional operational conditions such as different material properties, low gravity, and a moonquake. Micro-tunnelling or drilling to support lunar exploration and development of infrastructure on the Moon requires stability analysis to ensure its desired performance. The discrete element method (DEM) modelling technique has been utilised to investigate the optimum opening sizes on the lunar soil. From the literature, the mechanical properties of the lunar regolith have been reviewed and used for numerical model development. The model has been calibrated by simulating numerical triaxial tests with the Mohr–Coulomb failure criterion. Then, detailed parametric studies have been performed to investigate the influence of confinement, opening dimensions and moonquakes on the stability of openings. The findings have led to the development of a simple stability chart of the relationship between unsupported opening sizes and lunar regolith properties at different depths.

Nov 29, 2022

As a result of cheap Maui gas and plentiful hydro-electricity, over the past few decades New Zealand has enjoyed some of the cheapest energy of any OECD country. The situation is changing; at best we are facing some radical changes in energy use, at worst we are facing a crisis resulting from the following: &nbsp; Cause 1: Maui gas will be exhausted by 2012. Distorted pricing and supply contracts; resulted in Huntly Power Station, a coal mine mouth generator running on 70 per cent Maui gas until very recently! &nbsp; Cause 2: Investment in new generating capacity (and transmission) is woefully inadequate; as a result hydro lake levels are being continually pushed to the limits. &nbsp; Cause 3: Distorted thinking is everywhere, for example; æWe will find more cheap gasÆ. æGas is clean û coal is dirtyÆ. Hot air &nbsp;û ægreen alternatives such as wind generation will save usÆ. æNo NuclearÆ. The outcomes of the distorted thinking will be price increases, then shortages (there is nothing like "black-outs" to focus national thinking) and finally recession. &nbsp; But what can NZ do? - Mine Coal. Coal jump-started the industrial revolution, it can provide the transition to post-gas and oil. NZ has the second highest reserves of coal per capita in the world, yet we use less that any other country with significant coal reserves. Our exports of our best coal have increased threefold, yet out own consumption has remained static at about 1-1.5 Mtpa for the last 30 years. Our coal is NZ owned and inexpensive relative to other energy sources, even allowing for infrastructure and environmental costs. &nbsp; What can we do? We as mining professionals can promote informed responsible development and investment in the country&apos;s mining and energy business. We can galvanise public opinion on issues such as æunbundlingÆ our entire energy chain from mine-to generator-through transmission, even if the nuclear issue has to wait! With oil above US$70/bbl substitution is feasible. For individuals, there is always solar!

Jan 1, 2006

By P Woodward, T Ly, N Muhamad

OZ Minerals&apos; Prominent Hill copper-gold concentrator is located 650 km north-west of Adelaide in the Gawler Craton of South Australia. The concentrator was built in 2008 and commenced commercial production in early 2009. The Prominent Hill concentrator is comprised of a conventional grinding and flotation processing plant with a design capacity of 8 Mtpa. The flotation circuit includes six rougher cells, an IsaMill for regrinding the rougher concentrate and a Jameson cell preceding the three stage conventional cell cleaner circuit.Since its commissioning, the Prominent Hill flotation circuit has been the focus of a series of projects aimed at continual performance improvement. This has been achieved by a systematic approach of project identification, evaluation and implementation which has led to a progressive improvement in flotation performance. Innovations that have been successfully implemented include aspects of cell design and operation, and reagent suite optimisation.Improvements to the mechanical cells initially focused on the installation of a modified rotor-stator design in the rougher circuit, as recommended by Outotec. Isolated cells were fitted with this technology and proven to provide a benefit for copper recovery before the design was trialled in subsequent cells along the bank. Based on this success, further modifications were made to other aspects of the rougher and cleaner cells.Laboratory trials conducted at Prominent Hill involve a screening process identifying potential reagents from a list of products, which are then rigorously tested in the laboratory before one is selected for trial in the concentrator. Where these reagents have demonstrated a statistical improvement in performance they have typically been incorporated permanently into the flotation circuit. This paper discusses the process of continual improvement at the Prominent Hill flotation circuit and the optimisation achieved by the implementation of key initiatives.CITATION:Woodward, P, Muhamad, N and Ly, T, 2013. Optimisation of the Prominent Hill flotation circuit, in Proceedings MetPlant 2013 , pp 431-444 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013