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By M Field

Kimberlite pipes, as opposed to dykes, sill and secondary deposits, are the primary target for diamond exploration companies because they have simple geometries and can contain large volumes of potentially diamond-bearing ore. Once discovered, important decisions have to be made regarding the sampling of these geological entities to establish the total volume of ore present, and to define the internal geology, which can be complex in nature and controls the distribution of diamond grade. It is essential that as part of this process the uncertainty in constructed geological models are assessed. In this paper the Orapa AK1 kimberlite pipe in Botswana is used as a case study to explore a potential methodology for defining this uncertainty. The uncertainty of the rock volumes of different types can be characterised by a geostatistical approach. Geostatistical simulations, based upon a plausible representation of the geological bodies, provide different possible images of the orebody that can be considered as different realities. By testing different borehole layouts and drilling the orebody virtually on the computer, many different, but equi-probable realisations of the pipes can be produced. It is then possible to estimate the rocksÆ volumes and compare them with the actual ones. A statistical analysis of the relationship between estimation error and the number of boreholes can then be used to optimise the next sampling campaign. The rock volumes are obtained from a two-step simulation process. Firstly, the pipe geometry is simulated by means of introducing variations around the geological block model, by an original method called centre point simulation (CPS), which has been developed for this purpose. Secondly, the internal geology is then simulated within the pipe. The methodology for simulating the internal geological zones has to be adapted to the level of information and to the geological structure itself. The upper portion at Orapa AK1 is filled with sedimentary crater facies. Here plurigaussian simulation techniques can be applied that are adapted to the simulation of sedimentary facies. The central zones of the pipe are typically subvertically-oriented massive volcaniclastic deposits and breccias and the lower regions comprise a complex root zone. CPS is appropriate for these zones.

Jan 1, 2006

By X Yu, Y Shen

The iron ore products should be assessed in terms of in-furnace behaviour and overall furnace performance, their operation should also be optimised under industry-scale blast furnace (BF) conditions, in order to be sustainable and competitive, especially in the context of decarbonisation efforts in ironmaking. While lab and pilot-scale experiments can provide useful kinetics, they are expensive and risky and cannot replicate industry-scale blast furnace conditions for proper assessment and optimisation. In this paper, we review our recent progress at Shen Lab of UNSW in using state-of-the-art Computational Fluid Dynamics (CFD) models to assess iron ore products and examine the effects of their operations on BF behaviour in basic terms, including in-furnace phenomena (flow field, temperature field, species distribution fields etc) and overall BF performance (coke rate, reduction efficiency and top gas temperature etc). We have developed state-of-the-edge CFD models for different purposes, ranging from the static-state BF model featuring unique layered burden structures for offline assessment and optimisation knowledge building-up for iron ore products, to the transient-state BF model for online assessment and optimisation of iron ore productions by describing the transient behaviours of iron ore productions under industry-scale conditions. First, we have studied several iron ore products including the iron ore products used in the present BFs and emerging iron ore products like carbon composite briquette and iron-coke. Second, several iron ore operations are studied including optimisation of conventional burden operations like oxygen enrichment, batch weight tuning and new operations like coke central charging and hydrogen injection in BFs. Third, some time-sensitive operations are also investigated including the use of wet burden materials and the drop in blast temperature on BF performance. These CFD models offer cost-effective research tools for understanding the effect of iron ore products on BF performance and serve as a reliable marketing tool for existing and emerging iron ore products under a wide range of BF conditions.

Sep 18, 2023

By W Taylor, S Chen, R Haywood, M White, R West, J Ranasinghe

In March 2012 a combined BHP Billiton and Hatch team embarked on a program to improve the concentrate burner efficiency of BHP Billiton’s Olympic Dam copper flash smelting furnace. A multi-faceted approach including an analysis of the furnace using operational knowledge and first principles engineering led to the design and supply of a new central-lance (disperser). A new, patented, swirl method of introducing the copper concentrate into the furnace was developed to integrate with the existing concentrate burner. Plant trials in 2014 demonstrated an increase of nearly 10 percent in the oxygen efficiency of the furnace. The improved efficiency is expected to provide savings in operating costs and asset life extension of downstream gas and dust handling equipment.CITATION:White, M, Haywood, R, Taylor, W, Chen, S, Ranasinghe, J and West, R, 2015. Improved copper flash smelting at Olympic Dam, in Proceedings MetPlant 2015, pp 382–395 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

By Sagrabb T

In a company's quest for financing the development of a new mine, it will make calls on stockbroking houses and banks. The choice of the best-fit broker or banker is of great importance, and in the case of the miner, this is a house that has an intimate understanding of the mining industry, particularly one that has a solid staff complement of personnel with operating mine experience at a senior level. The most important document that the company will present to support its financing request will be the Feasibility Study. It cannot be too strongly emphasised that this document must be absolutely comprehensive and cover items including: (a) Geological review; (b) Resources and reserves; (c) Mineability; (d) Mining schedule; (e) Metallurgy; (f) Process plant description; (g) Infrastructure and services; (h) Management and operations; (i) Environmental and social impact; (j) Capital costs; (k) Operating costs; and (1) Financial analysis. The elements listed above represent major topics and require a great deal of expansion in the body of the document. Rothschild Australia Limited assists its client companies by supplying a detailed framework so that they will be in a position give the bank the information it needs to complete its technical `due diligence' study within a mutually agreed time. The client company will advance its position markedly if it uses well-known, reputable consultants to either complete or assist with the various aspects of the Feasibility Study. Such an approach will give the potential financier confidence that the company has taken a professional and unbiased attitude in determining the feasibility of the property in question. Most small- to medium-sized mining companies, both within Australia and overseas, will prefer, or will find it mandatory, to request a project funding package rather than opt for a corporate loan. This is because the company either does not want to tie all of its assets to the performance of one project, or that it is a one or two project company with no other substantial assets and is therefore unable to obtain a corporate loan. Upon receipt of the Feasibility Study, the bank will use the data supplied by the company in its cash flow analysis to build its own financial model. The purpose of this is to examine the timing of

Jan 1, 1994

Study on Separation Technology for Copper-Molybdenum Collective Concentrate

Sep 13, 2010

Upon cessation of mining activity open-cast mine pits typically fill with water, forming a æpit-lakeÆ. The water in these lakes, in some instances, contains high concentrations of ædeleteriousÆ material. Containment and/or dilution typically requires an understanding of how stratification in the pit-lake will develop over a long timescale (say 100 years). Vastly different transport rates can develop due to differing hydrogeochemistry, basin morphology and climate. Numerical (computer) modelling is the most likely approach for successful prediction over long times. While lake modelling tools are available, useful numerical modelling requires improved understanding of transport in such systems because they are different to natural lakes in a number of ways. Notwithstanding the effort required to improve our understanding, the modelling provide a means of testing approaches to active management of pit-lakes.

Jan 1, 2002

A genesis based on new developments in the physical chemistry and flow properties of colloidal substances is proposed for the pipe-like Peko orebody. The rheological behaviour of sediments is governed by the contained colloids. Remobilization of thick pasty sediment during diagenesis is regarded as an essential step in the concentration of metal dispersed in sediments. At a high concentration the sediment pore fluid is a dense gelloid such that van der Waals attractive forces between the colloidal particles exceeds the coulombic repulsion. This permits accretion of the colloids into globular clots and their fracture fragments. These have a uniform size distribution dependent upon the rate of shear, and the sediment lithifies to clotted, porphyry-like, "gritty", dolomitic or igneous-looking intrusions and flows. The physical chemical properties of natural sediment colloids appear adequate to account for ore formation.Adsorption accounts for the dispersion and retention of metal in sediments. Accretion accounts for the segregation of the colloidal materials to give the various types of clotted igneous-looking intrusive source rocks. Syneresis enables the colloids to spontaneously draw together and to dehydrate. Formation of an ordered lattice achieves a lower energy state and desorbs metals and insoluble metal compounds "particle by particle" into the escaping water of hydration and pore water. Peptization enables migration of the metal hydrosols as stable dispersions until they merge for outflow through seepage zones or water extrusion channels. Nucleation and concretion precipitate the metal dispersoids from pore waters seeping through hydrous parts of the source rock, porous beds, faults, and zones of weakness by which the connate waters leave the lithifying sediments. Gelatinous precipitated mineral matter in the ore channels is capable of thixotropic reliquefaction when disturbed by shock or movement. Local reintrusion, flowage, interveinings,brecciation, and intermixing of the materials is the result.The principles of the suggested genesis are applicable to both syngenetic and epigenetic mineral accumulations.

Jan 1, 1966

By S Hayton

While coal seam gas is considered to be an unconventional gas, the proliferation of areas under exploration and development mean that it is rapidly becoming main stream. The potential of New Zealand's coals to produce coal seam gas has been recognised for some time. However, key market drivers have not been suitable for the progression of this potential into reality. Kenham Holdings Ltd and CRL Energy Ltd, recognising the potential for the gas in New Zealand have initiated what is the largest ever assessment of New Zealand's coal seam gas potential. The premature demise of the giant Maui field has raised the focus of new gas developments and has increased interest in what we are doing. Over the past couple of years Kenham Holdings Ltd and CRL Energy Ltd have approached the assessment of the coal seam gas potential in a staged programme. Preliminary assessment of the data on the permit areas indicates that the potential resource may be up to 500 PJ. To date, preliminary appraisals have been completed or are underway on a significant number of fields. Exploratory drilling has been completed or initiated on several of those fields, with results from this work being fed into the preliminary modelling as it has become available. Given that in many of these areas there is no pre-existing information concerning their gas potential and world wide experience with lignite is practically nonexistent, it has been a steep learning curve with many surprises. However, initial gas content results and preliminary gas flow models have been on the whole, rather pleasing, with the commerciality of some developments already apparent.

Jan 1, 2003

By Riley S

Many regulatory bodies have, or are considering, guidelines that require rehabilitated mine spoils to be erosionally stable (satisfying quantitative limits) over specified design lifetimes. One of the problems facing the industry is that many of the computer models used for erosion assessment were developed for agricultural applications and are unable to predict the change in the shape of engineered landforms over extended periods of time. In particular, they cannot predict where valleys and gullies will develop in the landforms and how big or deep they will be. Furthermore, many existing models require considerable skill to use. A computer model (SIBERIA) developed by the first author, able to model this valley and gully development over long design lifetimes, and which is directly based on digital terrain maps is discussed here. Proposed rehabilitation strategies for waste rock dumps at Ranger Uranium Mine as assessed with SIBERIA are discussed. New features of SIBERIA of interest to the mining industry include the spatial distribution of erosion, deposition and gully development, and various measures of the quantitative risk of failure. A collaborative project with the Queensland Coal Association, involving the first author, aims to deliver these capabilities to the coal industry in a user-friendly package. The objective is the cost-effective rehabilitation of strip mines. Some preliminary results from this project are presented.

Jan 1, 1994

The AusIMM is concerned about the longer tem sustainability of the minerals sector in Australasia. Our contention is that the sustainability of the sector is at risk if we do not:   ò encourage more exploration in Australasia by removing impediments and         increasing incentives; ò fund our university and research centres appropriately to increase both our   prospectivity, and our processing efficiencies; and ò manage our human resources better.   This paper will focus on how we can better manage our human resources to assist in ensuring sustainability of the sector in Australasia .   From a production point of view:   Economic output = f (Land, Labour, Capital, Environment) where Land refers to all of the natural resources used in production. As well as land itself it includes water, forest, fisheries, oil, gas and mineral deposits. Labour refers to the skills and capabilities used by humans in the production process. Capital describes all of the manufactured aids used in the process of production1. The challenge for management is to ensure maximum efficiency and effectiveness of labour in the production process whilst maintaining sustainable development.   The 1992 Rio Summit defined sustainable development as maintaining and enhancing:   ò natural capital û defined as all natural resources, both environmental and   those of traditional economic value; ò manufactured capital û made by human kind, including produced goods,     infrastructure and built environment; ò human capital û defined as the health, well being, intellectual capabilities and   spiritual welfare of individuals; and ò social capital û defined as social relations and consultations within and   between societies, their norms and functionality2.   The minerals sector in Australasia has successfully focused on the technical aspects of each of these components of sustainable development with primary attention applied to natural capital and efficient utilisation of manufactured capital. The technical aspects of human capital and social have also been addressed through an emphasis on occupational health and safety and interaction with local communities however I suggest that, to date, insufficient emphasis has been placed on labour (human capital) to maximise economic output1.   It has become increasingly common practice to identify land as natural capital, labour as human capital and capital as physical capital. That is labour has been treated as a commodity rather than an opportunity to create a comparative advantage and this will be the greatest challenge for mine management to show leadership over the next decade of the 21st Century.   This paper will outline characteristics of the sector which are relevant to the management and utilisation of labour, outline the outcomes of recent AusIMM surveys, review the reasons for the current and future anticipated skills shortages, some innovative responses to the challenges and finally, suggestions on how mine management can show leadership.

Jan 1, 2006

Universal Resources Ltd has acquired a large portfolio of high quality exploration projects in two of Australia's most prospective regions for base and precious metal exploration: the Mt Isa Inlier (the Mt Isa-Cloncurry area) of North West Queensland, and the southern Lachlan Fold Belt in New South Wales. Drilling techniques commonly employed by the company for mineral exploration include diamond core drilling, air core drilling, reverse circulation (RC) drilling, and rotary air blast (RAB) drilling. Using examples from these two regions, each drilling technique is briefly described and compared, with particular reference to the specific advantages and disadvantages of each method for: sampling size, sample representivity, recovery, integrity and potential contamination. The applicability and implications of the different drilling techniques described for subsequent mineralogical and metallurgical evaluation work are discussed.

Mar 1, 2010

The Mount Lyell Mining Field is Australia's chief productive source of copper. It is situated near Queenstown, on the western flanks of the West Coast Ranges, about 20 miles from the west coast of Tasmania (Fig. 1).The following observations on the mineral composition of the copper ores of the Mount Lyell Field are based on a...

Jan 1, 1939

By A Giblett, K Afewu

This paper uses a case study to demonstrate best practices techniques for predicting the contribution of gravity concentration in a gold recovery process flowsheet. The case study was selected as an example of an ore with a marginal gravity gold content, which makes the value of a gravity circuit difficult to quantify. In this instance the value of leveraging a significant knowledgebase of operating gravity circuit performance to support the decision making process was demonstrated. This case study analysis serves as a useful demonstration of best practice methodologies supporting decisions to include or exclude gravity recovery in a gold recovery process flowsheet.CITATION:Giblett, A and Afewu, K, 2015. Do we need a gravity circuit or not? A case study in applying best practice, in Proceedings MetPlant 2015, pp 288–295 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

By Larkin F, Farrer E, McGhie R. R

The Electrolytic Zinc Company of Australasia Limited commenced productive operations during February, 1936, at the- Rosebery and Hercules mines, which are situated near Rosebery, Tasmania. At this time it was decided that before re-organizing the steel sharpening shop a test should be made of the relative merits of conventional drill-steel and detachable bits. For this purpose Ingersoll-Rand type"I" thread centre hole.jackbits were selected and seventy-two of these were tested against conventional steel. Results indicated that, under the conditions pertaining at these mines, j ackbits should prove more economical than conventional drill-steel bits, and that a large-scale test, under working conditions, should be made. This was done by gradually replacing conventional drill-steel with jackbits at the Rosebery mine. Results were satisfactory and by the end of 1936 both mines were using only the jackbits.

Jan 1, 1939

By C Rizzardi, M Callahan, J Mahon

Henderson Operation’s underground molybdenum mine has been in production since 1976. Since that historic date, more than one billion pounds of moly has been produced, and over 120 Mt of ore extracted from three different levels and many different panels. The safe and successful operation of Henderson has been, and will continue to be, dependent on utilising an increasingly sophisticated fleet of equipment, advanced designs, innovative mining techniques, best practices in maintenance processes, improvements in crushing and conveying systems, and most importantly, the training and mentoring of the underground staff. These ‘professional mining technicians’ have been essential in the safe and efficient operation and maintenance of the underground mine and convey systems, and will drive the continuous improvements needed to keep Henderson competitive in the growing global market.CITATION:Callahan, M, Mahon, J and Rizzardi, C, 2016. Development of the professional mining technician – Henderson’s underground mine continuous improvement program, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 161–166 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By M Pomery

BHP’s Western Australian Iron Ore Operations (WAIO) move approximately 250 million tons of ore per annum. The magnitude of the constant changes to the terrain models along with the diverse output and presentation requirements of numerous stakeholders presents significant challenges for the geospatial team. This paper describes how the WAIO Survey team use a combination of technology and optimised workflows to capture, ingest, publish and access large data sets for diverse stakeholder requirements. Machine learning for processing of data and the use of web based systems to track and prioritise task allocation of resources will be discussed in detail, in addition to the changes to the traditional roles of surveyors from the use of automation and mobile technology.

Sep 18, 2023

Mineral deposits of the central New Guinea region (Gunung Bijih, Ok Tedi, Mount Kare, Porgera, Frieda River) and of southeastern New Guinea (Wau-Edie Creek, Wafi, Hamata, Hidden Valley, Tolukuma, Misima) are associated with hot, forceful intrusions of magma of mantle origin that penetrated thick Precambrian and Palaeozoic continental crust. The interaction of high- temperature melt with continental crust, and the differentiation of melt while in transit through thick crust, may be factors in generating ore. Mineralised intrusives in central New Guinea are a result of Neogene- Quaternary magmatism and were emplaced in a foreland thrust belt environment, a setting similar to the (mineralised) Laramide intrusions of southwestern USA. In both cases, central New Guinea and the Laramide, magmatism is not obviously subduction- related. Mineralised intrusives in south- eastern New Guinea (Wau-Edie Creek, etc.), also, are in a thrust belt setting, and are not obviously subduction-related. The association of. gold in southeastern New Guinea with a second (Pliocene) phase of igneous activity, rather than with earlier (Miocene) activity suggests that re-working by successive intrusions may be a factor in localising ore. This is seen, also, in the Bismarck-Solomon islands region where the richer deposits are associated with later (Pliocene) intrusives rather than with earlier (Eocene-Oligocene) intrusives. Unlike the mainland mineral deposits, those of the Bismarck-Solomon islands are clearly subduction-related.

Jan 1, 1991

Review of the mining legislation in New Zealand has coincided with a number of radical changes. These include a redirection of economic management towards a more open and competitive economy; major reform of the state sector aimed at greater efficiency, transparency and accountability; a new environmental administration; and a fundamental review of policy for management of natural and physical resources. These changes provide an opportunity to develop a consistent and coherent approach in the minerals and related statutes that will achieve objectives of economic efficiency, equity, practicability and good environmental management.

Jan 1, 1987

By A B. Christie, S C. Cox

Effective land-use planning requires accurate knowledge of mineral resource potential. Mineral companies during reconnaissance exploration, feasibility investigations and mine development also use this type of analysis. The Institute of Geological and Nuclear Sciences is undertaking a two-year project reviewing the resource potential of the West Coast of the South Island of New Zealand. Spatial prospectivity models have been developed as part of this resource assessment process, using computer based statistical pattern recognition techniques to delineate areas that are prospective for mineral deposits and to test deposit genesis models. Digital GIS data-sets of mineral occurrence were correlated against geology and exploration information. The distribution of mesotherrnal shear zone gold deposits in the Reefton Goldfield, were examined against geological data-sets from both the regional (QMAP) and local prospect-scale mapping. Weights of evidence analysis generated a correlation matrix that highlights relationships and degrees of association that might otherwise not normally be recognised.   Mesothermal shear zone gold deposits have strong positive spatial correlations with Greenland Group host rocks and areas with moderate to high quartz vein densities; moderate-strong positive correlation with regions <500 m from folds, with regions <600 m from faults and five to eight kilometres from granite contacts; moderate correlations with Ntrending fault and fold segments; and no/weak/poor correlations with fault intersections, fold-fault intersections, bends in regional structures and magnetic and radiometric data. The regional and prospect scale data sets give different results, with the more detailed prospect scale mapping giving generally better correlations. This emphasises the value of detailed geological mapping in the exploration process.   Maps generated by prospectivity modelling consistently highlighted areas of known mineralisation and generate targets where follow-up investigation is warranted. The prospectivity per unit area provides a measurable value that should change as new information comes to hand and, in addition to highlighting targets, can be used to measure the impact of increased exploration expenditure and assess the effectiveness of exploration investment.

Jan 1, 2001

By D L. Reid, G Nwaila, J Petersen, J-P Franzidis, Y Ghorbani, M Becker, F C. de Beer, L C. Bam

Traditional methods of gold extraction have involved comminution and processing via cyanide leaching, all of which are associated with energy, cost and environmental implications. Subsequently, numerous opportunities for improvement and optimisation strategies in gold mining and processing have been explored, including heap leaching, which has significantly lowered comminution costs. This paper explores the effect of the more energy efficient high-pressure grinding rolls (HPGR) on the comminution behaviour (especially on the crack density) and cyanide leaching performance of laboratory reactors study on run-of-mine gold ore comprising the Ventersdorp Contact Reef (VCR) and the Elsburg Reefs (ER), sourced from Carletonville in the Witwatersrand Basin in South Africa. The ore was comminuted using HPGR at three different pressure settings (120, 90 and 60 bar). Large (-16/+11.2 mm) and small (-5.6/+4 mm) particles of the HPGR product where then mineralogically characterised using optical microscopy, quantitative evaluation of minerals by scanning electron microscopy (QEMSCAN) and X-ray computer tomography (CT) before cyanidation. The results of the leach experiments indicated a correlation between gold extraction, particle size and crack density. Mineralogical characterisation of the ore indicates that the Fe-sulfides present in the VCR are likely to be more reactive than those in the ER, thus having a more favourable influence on gold cyanidation. Overall, the results show promise for the heap leaching of Witwatersrand gold ores prepared using HPGR and demonstrate the value of a multi-disciplinary geometallurgical approach.CITATION:Nwaila, G, Becker, M, Ghorbani, Y, Petersen, J, Reid, D L, Bam, L C, de Beer, F C and Franzidis, J-P, 2013. Morro do Ouro geological model with a metallurgical view, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013 , pp 75-84 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 29, 2013