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By B J. Andrew, M R. Daley

Mount Isa Copper Mines is a world-class mining operation producing approximately six million tonnes of ore per annum. With over 50 years of mining history and over 76 million tonnes of underground resource remaining there are many challenges facing the mine technical team today and into the future. The mine consists of nine distinct areas: the Hangingwall Lens, Footwall Lens, 1100, 1900, N1100, N1900, 3000, 3500 and N3500 orebodies. Each of these areas have different characteristics, requiring varying methods of mine design and ground control for safe and efficient orebody extraction. Each of the areas operate with an independent sequence whilst interacting with the entire underground operation. Within the first five years after graduating mining engineers tend to orient their careers in either a technical or operations direction. Engineers working towards a specialised technical career will often be working as mine planning engineers, whilst others more focused in the operations stream occupy roles such as operations or project engineers. At this stage of a mining engineerÆs career they are not yet categorised into one stream or another, but career decisions made now can generally focus their ultimate career path in one direction or the other. Due to the size of the Mount Isa operations there are many opportunities for engineers pursuing both career path and plenty of room for growth forthose as yet unsure.

Jan 1, 2005

By S Paciornik

The traditional trading of iron ores is based on chemical specifications and particle size distribution. However, recent characterisation studies, that bring additional information like mineralogical composition and microstructural (textural) aspects, have become important. They contribute to determination of the iron ores downstream beneficiation operations and subsequent steelmaking processing, allowing improvements on both new and existing processes. Despite progress in commercial scanning electron microscope/energy dispersive spectrometer (SEM/EDS) automatic instruments in the last decade, these systems are not capable of performing the identification and discrimination of major iron ore minerals (haematite and magnetite) and the consequent description of its microstructure. On the other hand, reflected light microscopy (RLM) can easily distinguish the iron oxides by their reflectancies, but it cannot discriminate quartz and epoxy resin, which present similar colour on images. The present work proposes an innovative method to perform a quantitative mineralogy characterisation of iron ore based on RLM-SEM co-site microscopy. This technique combines images obtained by RLM and SEM through an automatic registration procedure that accurately aligns the two kinds of images of each field. In fact, it creates multi-dimensional images, which are then analysed using image processing and pattern recognition techniques. The case study is an itabiritic iron ore from Quadrilßtero Ferrffero (Brazil) which contains mainly quartz, goethite, magnetite and haematite. The discrimination of phases that are not distinguishable with either RLM (epoxy resin and quartz) or SEM (haematite and magnetite) can be performed through this multimodal approach, allowing the subsequent mineralogical quantification. The mineralogical quantification computed by image analysis was consistent with independently obtained results based on the Rietveld technique.

Jan 1, 2008

By Miller D. R

The mineral exploration and extraction industries have gained major cost and efficiency benefits from the use of computers. However these industries are now at a cross-roads with two seemingly disparate developments - that of an increasing number of complex geoscience databases and, at the same time, the merging of all known data for the particular regions at minimal cost. These two developments can be managed by the development and of an industry accepted geoscience data model and dictionary. This will provide a common basis of understanding for geoscience data through a common language and a common structure for geoscience information. Integration of specialist systems and databases can then proceed efficiently. The development of a data model is going ahead with consensus from the mining industry. This is a joint government and industry funded project and managed through the Australian Mineral Industries Research Association, AMIRA. AMIRA is a well known research broker to the Australian mining industry obtaining sponsorship for projects both from private and government groups. The AMIRA project, P431, called the Geoscience Data Model, is to be the Australian standard data model for geoscience disciplines. The requirement for a standard geoscience data model has been recognised in Australia for some time. In October 1991, the Australian Government Geoscience Database Policy Advisory Committee (GGDPAC) established a Geoscience Data Standards Working Group which drafted a comprehensive list of data categories of the geoscience area. An AMIRA project called AMDEX was established to develop a transfer standard for the mining industry data at about the same time as this committee was in operation. The first AMDEX sponsors meeting was held in May 1991. It was proposed to use the US Spatial Data Transfer Standard (SDTS) as the basis to transfer mining data in AMDEX. A limited data model of mining data to be transferred was developed for the AMDEX standard under SDTS. The Australian Geological Survey Organisation (AGSO) saw the need to extend this and develop a complete data model for the geosciences and proposed this as a new project to AMIRA. This was strongly supported by GGDPAC which lead to sponsorship of the project from most state geological surveys. The Geoscience Data Model can be broken down into separate data models for a number of geoscience themes and sponsorship obtained so far will enable models to be developed for a comprehensive set of themes selected by the project sponsors. Further sponsorship is required to enable a more complete coverage of the geoscience area to be developed. Sponsorship for the Geoscience Data Model has been strong from the geological surveys and there was some effort by GGDPAC to promote the project in these organisations. An Australian geoscience data model is of immediate use to the geological surveys in assisting the standardising of huge quantities of geoscience data held by government agencies and it is preferable that this be an Australia-wide standard.

Jan 1, 1995

The optimisation of capital in the total planning context has broadly two components: ò maximising the efficient utilisation of capital against competing capital demands; and ò maximising the efficiency with which the industry's capital requirements are sourced. This paper focuses on the latter of these two concepts, as I wish to highlight that within the coal industry the inefficient sourcing of capital has resulted in the inefficient utilisation of capital. In discussing the optimisation of capital within the coal industry I would like to outline three fundamental issues which currently impact the industry and its application of capital: Initially, from the perspective of an independent investor, the perceived risk associated with investing in a volatile industry cycle has not permitted appropriate funding structures to be created thus leading to an inefficient utilisation of capital. Secondly, investors seeking out a windfall gain have established a practice of trading in the assets rather than encouraging recapitalisation. And lastly the mismatch of supply and demand leading to the establishment of new projects which include a percentage of offshore investment has fostered an environment of lower returns and subsequently a dilution of capital.

Jan 1, 1991

By Miskelly N

The Joint Committee of The Australasian Institute of Mining and Metallurgy (AusIMM) and the Australian Mining Industry Council (AMIC) have published a Code for the Reporting of Identified Mineral Resources and Ore Reserves. The Code is the result of an initiative begunin 1971 to achieve industry self regulation of Resources and Ore Reserves reporting which resulted first in guidelines for reporting standards but which have now been incorporated in ASX Listing Rules as a Code withsignificant sanctions ensuring compliance. This paper describes the background to the Code, its key provisions, and comments on practical aspects of1 working with the Code and compliance issues.

Jan 1, 1990

By Adam R. A

Techniques for the optimisation of open pit design and development are now accepted as standard practice in the mining industry. These techniques are used to analyse the impacts on project profitability of factors such as product price, slope design criteria and equipment selection. A fundamental assumption used in this type of analysis is that dump and stockpile designs and sequencing are predetermined. The cost of haulage for a typical truck shovel mining operation is in the range of 25 - 50 per cent of mine operating costs. Substantial cost savings can be achieved by optimisation of dump design and location of associated road and ramp systems.Factors which affect both the operation and total cost of dumping include; Ramp gradients and location, road design, dump placement and shape, dumping height, slope design (interim and final), slope stability, environmental requirements and equipment selection. This paper discusses these factors and their effects on the total mining operation and project value. Reference is made to case studies in which some of these factors have had a significant impact.

Jan 1, 1992

Natural gas from the south west Queensland gas fields is now available in north west Queensland to fuel the development of many Carpentaria Mineral Province projects. Like these projects, the south west Queensland gas project, developed under the operatorship of Santos Ltd, has its own æMining CycleÆ. While the project is entering its third expansion phase, it is at the same time actively extending its discovery phase, with large programs of gas exploration and reserves definition. This paper outlines the history of the south west Queensland gas project, with particular emphasis on the relationship of the project to north west Queensland.

Jan 1, 1998

By M Gao, V Lawson, W Valery

Changes in metal prices and mine output over recent years have required the Copper Concentrator of Mount Isa Mines to operate at annual tonnage rates varying from 4.0 million to 6.5 million tonnes. Several circuit combinations were operated during this period utilising up to two semi-autogenous grinding (SAG) mills and up to two ball mills. The aim was to maximise grinding efficiency and keep unit costs constant regardless of throughput rate. Measures to improve the SAG-ball mill unit operation were implemented with each circuit change. These included installation of a splitter to divert SAG Mill cyclone underflow back to the mill, increase SAG ball charge from four per cent v/v to eight per cent v/v, reduce in SAG top feed size and increase of ball mill grinding medium size. Modelling work and surveys led to a new design of the SAG liner profile from 60 rows of rail bar liners in a high-low arrangement to 40 rows of top hat liners in a high-high arrangement. An on-line SAG Mill feed sizing monitor was recently installed to improve grinding control.

Jan 1, 2000

By A Torpy, N C. Wilson

Improvements in electron optics, field emission gun design, and X-ray detector technology have led to the development of a new class of microanalysis tools. By combining multiple wavelength dispersive (WD) spectrometers, spectral energy dispersive (ED) spectrometers and cathodoluminescence (CL) data sets, a wealth of information can be collected during routine electron beam mapping and analysis. In this paper, data collection on a field emission electron microprobe equipped with five wavelength dispersive, two silicon drift energy dispersive X-ray spectrometers and a wavelength dispersive linear array optical spectrometer has been automated with the optical, electron and X-ray signals being collected in parallel. To analyse the large hyperspectral data sets we have implemented an autoclustering strategy that can be used to produce a quantitative chemical phase map. The cathodoluminescence spectra can be deconvoluted to produce peak intensity maps, which are then converted into elemental speciation images with quantitative sensitivity down to parts per million levels. Both methods are illustrated using typical mineral processing examples, firstly a Ni-laterite sample is investigated with the fine-scale distribution of Ni examined in detail. Secondly, a scheelite sample with rare earth zoning in mapped and rare earth levels quantified.

Jan 1, 2008

Late Cretaceous and early Tertiary coals in the Greymouth, Ohai and Kaitangata coalfields represent a major national energy resource comprising-up to 2500 x 106 tonnes of coal in ground. The three coalfields are closely related in terms of age and sedimentary and structural character. The most striking feature common to all is the complexity of the geology which has severely restricted exploration and mining of these coal resources. This complexity is manifest in the irregular lensoid nature of coal seams and by the incidence of unpredictable medium and small scale faulting and folding. There are many geological similarities between these coalfields which are considered to arise from a common origin which can be related to the plate tectonic evolution of the southwest Pacific region. In order to efficiently assess and exploit these coal resources it will be necessary to know their geology in great detail. This can he achieved by increasing the understanding of the sedimentary and structural evolution of the coal bearing basins. This knowledge may be gained by the application of traditional (ie drilling, field mapping) and innovative techniques (ie high resolution seismic, in seam seismic) with on going research-oriented studies (ie basin analysis, coal petrography).

Jan 1, 1987

By A J LYNCH

It was Harold McMillan, Prime Minister of England 30 years ago, who used the phrase "The Wind of Change" to describe political events in Africa in his day. So well did this phrase capture the spirit of the time that it echoed around the world, and the echo has never stopped. Change is the constant factor in the society in which we live and everyone of us has had experience of the effect which it has had on our professional and personal lives. Change will not stop, it will continue at an increasing rate and the questions we must answer are how do we prepare ourselves to meet the challenge of future change and how do we take advantage of the opportunities which it will bring? It is these questions which I wish to discuss in this address.

Jan 1, 1989

By J Manuel, N Ware

Ideal iron ore sinter is produced by optimising the balance between coarse (+2 mm), stable ore nuclei and a reactive matrix consisting largely of fluxed -1 mm fines. The authors have previously published work evaluating the matrix melting behaviour of a number of fine ores, using techniques developed by CSIRO. The focus of that work was to demonstrate the contribution of the matrix to overall sinter quality, with the results showing a direct correlation between melting point, matrix porosity and strength. CSIRO has also developed a complementary test to study the behaviour of coarse ore nucleus particles in contact with the sinter matrix and provide an evaluation of their reaction and assimilation properties. This test provides valuable fundamental information that can be used to better understand the role of specific ore types and optimise blend composition.The CSIRO laboratory-scale assimilation test is carried out by embedding particles of ores of specific sizes into a fluxed matrix of known sinter blend composition, using real ores and fluxes, in a laboratory test that directly relates to pot-grate and plant sintering conditions. Samples are fired under controlled conditions in a tube furnace using a standard heating profile and a constant, low-oxygen potential atmosphere. These conditions simulate the actual sintering process while removing the effects of the many locally-variable parameters (eg temperature, oxidation potential and localised chemistry) that exist in the actual process, meaning that trends in behaviour can be more clearly seen. Designed as a compromise between the industry-standard pot-grate sintering test and a more fundamental test using chemical reagents, the aim is to isolate and evaluate the nucleus behaviour of an individual blend component to allow an improved understanding of the role that an individual ore plays in a specific blend. Measured cross-sections of the resulting fired samples provide a semi-quantitative measure of reactivity, while accompanying photomicrographs allow a qualitative assessment of assimilation properties (eg volume and distribution of secondary porosity generated during reaction).In this paper, to complement the previous work published on melting behaviour, nucleus particles were selected from hematite, hematite-goethite and goethite ores and embedded in a simulated plant sinter matrix. Drilled core particles of two sizes were tested at fixed temperatures simulating low- (<1300°C) and high-temperature (>1300°C) sintering conditions. The resulting assimilation properties are compared and discussed as a function of particle size, temperature and ore/sinter mineralogy. The implications for the contribution of each component to the prediction of blend sinter quality are also discussed.CITATION:Ware, N and Manuel, J, 2015. Fundamental nucleus assimilation behaviour of hematite- and goethite-containing ores in iron ore sintering, in Proceedings Iron Ore 2015, pp 77–82 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

Companies involved in the mining industry are exposed to risks, referred to as corporate risks, as part of the business process. Directors and management should be aware of these risks and make appropriate business decisions to address each risk. If business risks are not addressed on a timely basis the consequences are likely to be serious and will adversely impact the ultimate success of the business.The key corporate risks are:Poor cash flow and treasury management. ò Incompetent or unmotivated staff.ò Poor product quality.ò Accounting systems that do not provide meaningful and timely information.ò Computer system deficiencies. ò Ineffective credit screening.ò Assets not adequately protected.ò New ventures undertaken that are either inappropriate or not adequately researched.Exposures to corporate risk should be dealt with by Directors and management by systematically identifying major risk areas and implementing appropriate internal and management controls to deal with such risk areas. Proper management controls and procedures include the setting of overall corporate objectives and policy, monitoring adherence to such policy, establishing early warning systems to highlight problem areas and maintaining security over assets.

Jan 1, 1990

The philosophy of computer control of grinding and flotation at ZC/NBHC is presented. The performance and reliability of the in- stalled systems are discussed.

Jan 1, 1978

By Espinosa-Gomez R, Johnson NW

The Copper Concentrator at Mount Isa Mines Limited treats on average 18 000 tonnes/day of chalcopyrite ore containing typically three per cent copper. The main gangue minerals are iron sulphides (-13 per cent) and non sulphide gangue (-78 per cent). In August, 1991, the comminution flowsheet was changed from a conventional circuit (crusher/rod mill/two stage ball milling) to a modem circuit (fully autogenous grinding/one stage ball milling). The 80 per cent passing size of the flotation feed with the conventional circuit was 125 microns. The Copper Concentrator has two parallel grinding lines, two roughing and scavenging flotation lines, and common cleaning, recleaning and retreatment sections. During the first six weeks of the installation phase, one of the two flotation lines was fed by the conventional grinding circuit and the other by the autogenous grinding circuit. Data from parallel surveys and historical data are used to analyse the rougher/scavenger flotation performance before and after the change. The solid and mineral distributions of the flotation feed, the pulp chemistry and the reagent requirements are compared. The mineral liberation before and after the installation of autogenous grinding is compared on a sized basis using data from the 14 consecutive months before, and the seven months after the change. Liberation was measured using the QEM*SEM(*) instrument. The overall effect of the new grinding circuit on the plant metallurgy is also assessed using the copper recovery values, the dilution of the final concentrate and the distribution of copper losses in the final tailings. (*) Quantitative Evaluation of Materials by Scanning Electron Microscopy

Jan 1, 1993

A mining operation can be identified as demonstrating prudent management when a number of vital characteristics are evident.All risks and opportunities that are critical to the on-going success of the operation have been identified and are being effectively managed. All significant tasks and events are plan driven. All levels of management visibly support the policies of the operation through their attitude, behaviour and actions as well as words. Supporting evidence for required activity and the outcomes is readily available. Improvement mechanisms are working to advance the key business processes. Everyone is working towards satisfying the needs of the stakeholders of the operation. When these characteristics are integrated with the satisfaction of all legislative requirements, all industry codes and optionally all relevant international management system standards then an operation is fulfilling all the requirements of a Due Diligence Process. The majority of mining operations do not show all of these characteristics and therefore unnecessarily suffer from missed profit opportunity and constant cost pressure, less than acceptable safety and health and environmental performance and consequent poor relations with employees, unions and regulators. In these operations the characteristics to be observed are quite different.Serious incidents are occurring with no sign of a rate decrease. The operation lurches from one panic ituation to another. Management are absent in their leadership, but very active in developing rules and enforcement methodologies. The operation has no history. Re-inventing the wheel with employees who come and go at an alarming rate seems to be forever occurring. All efforts are directed at controlling the business outputs with a strong emphasis on blame. Everyone is trying to look busy to avoid the ever-present cost reduction threats. To change to more prudent management utilising a Due Diligence Process is not theoretically difficult. However it does take clear direction, focussed efforts, supporting actions with appropriate tools and perhaps most importantly an internal desire and drive to become such an operation. A Due Diligence Process is about doing the important things that have to be done, providing the understanding of why they are important, demonstrating proof of activity and effectiveness, and leading the way through effective management.

Jan 1, 1998

By Glasson K. R

The history of Ore Reserve classification and reporting in Australia is largely a history of the Australian mining industry itself. In the late 1800s, when the industry was dominated by small scale, high grade underground mines, Reserves (if estimated) were based on hand sampling and geological inference, and reporting of Reserves was either non-existent or of extremely variable quality. By the mid-20th century, the industry was dominated by large underground base metal and gold mines. Reserve estimation was coming under the control of skilled geologists and mining engineers, however Reserve classification and reporting standards continued to vary in type and quality from mine to mine. Today, large scale, low grade mining operations predominate, and Reserve estimates are generally based on extensive drilling results processed (with geological control) by computer. Through the efforts of a Joint Committee established by The Australasian Institute of Mining and Metallurgy and Australian Mining Industry Council, Reserve and Resource classification and public reporting has been standardised and controlled by adoption of the ""Australasian Code for the Reporting of Identified Mineral Resources and Ore Reserves"" released in 1989. The Code, which will continue to be modified and improved by the Joint Committee, has also been used as a basis for guides to reporting in other countries, and there is now some hope that this difficult and vexing topic may finally become subject to international standards and controls.

Jan 1, 1992

In the Massif du Sud ophiolite complex platinum group elements occur predominantly as ultrafine-grained inclusions of rutheniridosmine, laurite and iridosmine. These form primary inclusions less than 5 to 10 um in diameter within chromite in podiform chromitite fringed by dunite, and emplaced subsequent to solidification of the host harzburgite. There is no specific association with trace inclusions of transition metal sulphides. The crystallization of then: Ir. Os and Ru minerals may have occurred concomitant with hromite, perhaps related to more reducing conditions produced by crystallization of the chromite. The Ir, Os. and Ru show pronounced fractionation from Pd, Pt and Rh expected to be also present in the mantle source rock. The dunite shows evidence of metasomatic origin from adjoining harzburgite, and the possibility of selective crystallization of the Ir sub-group elements suggests that Pd, Pt and Rh may have been transported elsewhere.

Jan 1, 1989

By G Chitombo

Mass mining methods have become the mining industry’s preferred way of extracting most of the world’s most important metal and mineral commodities. Given the rapidly increasing global demand for commodities, the requirement to increase the contribution of some of these (eg copper and gold) from underground sources also continues to grow. In the case of copper this contribution is needed by a number of major producers to supplement production from their ageing deep open pits. Satisfying this increased demand will require the design, construction and operation of more effective, higher capacity and larger scale mines which, in turn, will require enhanced mass underground mining techniques such as block caving (BC), panel caving (PC) and sublevel caving (SLC).It is now widely accepted that future discoveries of orebodies, which will be developed using these methods, are almost certainly to be much deeper than the deposits presently being mined in this way and made more challenging because of the likelihood that the associated grades may be much lower than currently mined. The design and mining of future large-scale cave mines (supercaves) will become crucial in order to extract full value from such deposits. An essential prerequisite of this will be a much improved knowledge of the deposit, ie Total Deposit Knowledge. In this context, Total Deposit Knowledge is the characterisation of the ore deposit and its surrounds at all scales and includes; rock type (lithology), the spatial orientation of a range of geological features or discontinuities, rock mass fabric knowledge, metal grade and distribution data, geometallurgical data (including alteration), geo-hydrology, permeability and porosity. This is the information that will be used, as now, to delineate geological and geotechnical domains and construct models, but with outcomes superior to those presently available. From this information better-informed feasibility study design decisions and performance predictions must be made. In summary more geological information and analysis is required and this needs to be aligned to potential mining and processing requirements much earlier in the project than commonly occurs.

Aug 22, 2011

By Mining Geophysics

Modern geostatistics has eliminated much of the guess-work in ore reserve estimation, and can calculate levels of confidence for the reserve estimate. Geological modelling software has brought about a revolution in the communication of complex geo-variables to mining engineers, metallurgists, surveyors and managers. Mine planning and scheduling can now avail itself of a veritable toolbox of enabling technologies.

Jan 1, 1994