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The design of a mine should aim to optimise the market value by maximising revenues whilst minimising costs. In open pit mining, the nature of the extraction technique translates this objective into the maximum recovery of reserves while minimising waste extraction subject to technical, economical and safety constraints. Since the introduction by Lerchs and Grossman, in 1965, of a model that is now considered a classic in the area, open pit design has reached a level of maturity and acceptance by industry. These models are being used on a regular basis by designers and planners.This paper proposes a new alternative model for open pit design. It is based on genetic algorithms (GA) and exploits a reduction of the number of decision variables of the more traditional techniques. The novel approach provides more flexibility than traditional models; it can also be extended to consider planning problems that traditional open pit design models are not capable of handling. The algorithm has been designed for two dimensional problems and tested in a simple instance. The results obtained in this simple test are encouraging and are a good supporting argument for the development of a GA model capable of handling three-dimensional (3D) instances. The model presented in this paper is just a first step towards a full GA to solve the pit design problem and it is believed that novel tools like the one presented herein could become great allies in tackling challenging problems in open pit design, an illustration of such a challenging problem is presented and discussed.

Dec 6, 2010

By G Q. Xie, J W. Mao, Y B Cheng

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The East China Mesozoic metallogenic province hosts the world’s largest resources of tungsten, tin, molybdenum, antimony and bismuth, with additional important gold, silver, mercury, lead, zinc, copper, uranium and iron deposits. These deposits form several giant metallogenic belts, including South China, Middle-Lower Yangtze River Valley, East Qinling-Dabie, eastern North China Craton and North-east China. Available data demonstrate that these metallogeneic belts are the products of episodic magmatic and related hydrothermal events between ~240 and ~80 Ma. Each magmatic-hydrothermal episode has produced distinct deposit assemblages that can be readily linked to the Mesozoic geodynamic evolution of East China, involving continental collision between the North China Craton and South China Block at 220–200 Ma, oblique subduction of the Izanagi plate under the Eurasian continent at ca 170–135 Ma and post-subduction extension and lithospheric delamination at 130–80 Ma. Metallogeny in north-eastern China is more complicated due to prolonged tectonic evolution related to southward subduction of the Mongolian–Okhotsk plate and westward oblique subduction of the Izanagi plate, and subsequent continental collision and post-collisional processes.CITATION:Mao, J W, Xie, G Q and Cheng, Y B, 2015. Mesozoic metallogeny in east China and their geodynamic processes , in Proceedings PACRIM 2015 Congress, pp 631–636 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

Access to the Rosebery Orebody, which dips into the western slopes of Mount Black at 45¦, has been achieved in sequence by the following means: - A series of adits down to 8 level - An inclined shaft (No. 1 Shaft) sunk internally from 8 level to 14 level - A vertical circular concrete lined shaft (No. 2 Shaft) sunk internally from 4 level to 19 level. Although the orebody has been fairly well defined to 19 level, deeper ore occurrences have been outlined by a series of drill holes decreasing in frequency with depth to 26 level. No. 2 Shaft (sink) was stopped some 10 m below 19 level in order to make an early start on doubled production at West Coast Mines, with the intention of subsequently extending the shaft or of driving a decline from the lowest operating horizon for deeper access. The decline approach was adopted some six years after production commenced from No. 2 Shaft. The reasons for that decision are outlined, together with an account of the constraints and design requirements imposed by commencing by a vertical shaft in the hanging wall of the orebody.

Jan 1, 1982

By G R. Howard, G Back

Management of information systems for data collection is essential to maintain data integrity and continuity, and manage loss control on a large world-class mine such as Telfer Gold Mine. This paper aims to describe the individual systems and protocols of geological data capture at Telfer, then focus on Quality Assurance Quality Control data as an example of loss control in practice. Loss control systems are required to provide capacity, flexibility, structure and management tools to enhance data interrogation. The data that have been collected can then provide geological, financial, environmental, and contractual information to optimise management of business best practice. Telfer Gold Mine is a wholly owned and operated subsidiary of Newcrest Mining Limited. The mine is located in a remote area of NW Western Australia, and has been operating for 20 years. Geological data have been collected at Telfer since 1973. The data include drilling, assay, geological, survey, structural and geophysical data. Data management has evolved through many systems with data stored on many different hardware and software platforms. Commencing in 1995, collation, standardisation and validation of the historic data was completed. This has resulted in the first Access based drill hole database incorporating all available drilling data. This drill hole database, now hosted in SQL Server, is the hub for all geology related data management systems. The Telfer Gold Mine Geology Department has developed a series of inter-related database systems in order to manage the core geology business issues. Databases relating to drill hole planning, drill contract management, geological logging, accounting (standard costing, forecasting, invoice reconciliation), quality control (QAQC), and environment rehabilitation have all been developed to manage loss control. Management effort to provide adequate data systems and protocols has driven the system from concept to utilisation. The improved productivity, data integrity and data analysis capabilities provided by the new database systems at Telfer have allowed for greater confidence in decision making. Systems such as the drill hole and QAQC databases, when utilised in the proper manner provide up-to-date data analysis for resource audits and contract negotiations. The loss control systems are essential to maintain confidence in data integrity and hence directly effect the future of mining at Telfer.

Jan 1, 2000

By R G. Skirrow, M Cooper, J Claoué-Long, K Czarnota, H Dulfer, J Thorne, D C. Champion

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. Tholeiitic intrusion-hosted nickel (PGE-Cu) sulfide deposits are under-represented in Australia’s inventory of known resources of this deposit type, relative to regions globally with comparable geology. To support discovery of major new deposits, a continental scale analysis of Australia’s potential for tholeiitic intrusion-hosted nickel (PGE-Cu) sulfide deposits is being undertaken. The analysis applies a mineral systems approach to map the four essential components of the ore-forming systems:1. sources of ore constituents2. crustal and mantle lithospheric architecture3. energy sources or drivers of the ore-forming systems4. gradients in ore depositional physico-chemical parameters.The results reveal several regions of Australia with potential for discovery of large tholeiitic intrusion-hosted nickel (PGE-Cu) sulfide deposits, mostly around the margins of Archean and Proterozoic lithospheric blocks. These include the south-east and northern margins of the Yilgarn Craton, the south-west and south-east margins of the Kimberley Block, the southern margin of the Arunta Province in central Australia, the western flank of the Gawler Craton in South Australia, and possibly some areas within the Palaeozoic Lachlan Orogen of eastern Australia.CITATION:Skirrow, R G, Dulfer, H, Czarnota, K, Champion, D C, Thorne, J, Cooper, M and Claoué-Long, J, 2015. Australia’s potential for nickel sulfide ore systems – a new continental-scale time-space framework for exploration, in Proceedings PACRIM 2015 Congress, pp 679–684 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

The Sams Creek gold deposit near Takaka in northwest Nelson was discovered in 1974 by CRA Exploration (CRAE) geologists. CRAE recognised the potential of the area and subsequently undertook a comprehensive exploration programme of geological mapping, soil and rock-chip sampling, geophysical surveys and diamond drilling. Exploration defined sporadic gold mineralisation contained entirely within a deformed and hydrothermally altered, peralkaline granite porphyry dyke with a seven kilometre strike length, and up to 60 m thickness. Rock chip samples indicated extensive and economically significant gold grades over approximately one kilometre strike of the dyke at Main Zone prospect. CRAE completed 30 diamond drill holes at this prospect and defined a limited resource. Oceana Gold Limited recommenced active exploration at the Sams Creek Project in late 2002, focusing on improving the geological understanding and known resource at Main Zone. Completion of 1041 m diamond drilling successfully increased the estimated resource to 10.7 Mt @ 2.12 g/t Au containing 729 000 oz at a 0.7 g/t cut off. A further campaign of 1560 m diamond drilling was undertaken in 2003 - 2004 to extend the resource and test the continuity of high grade mineralised zones. Deeper intersections of the porphyry dyke indicated geometrical complexity and grade variability similar to that observed at shallow levels. Recent research suggests that Sams Creek can be geologically classified as a variant of intrusion-related gold systems, and therefore comparable to some other, very large gold deposits. However, due to the rugged terrain and dyke geometry, surface drilling is reaching the limits of viability at Main Zone. If infill drilling continues to be successful then an underground decline may be developed to facilitate further exploration. Potential also exists along strike, where other significant gold anomalies are known but largely untested by drilling.

Jan 1, 2004

By A Kitchen

For the past decade, demand for Australian resources has reached unprecedented levels, thanks mainly to the emerging superpowers of China and India. Meeting demand has meant miners and governments alike have ploughed billions into capital expenditure projects for logistics infrastructure such as roads, rail and ports, to support the ever expanding number of mines and mineral volumes. In more recent times, however, the effect of the global economic crisis has led to a decline in demand for Australian minerals. The downturn has seen companies lay off workers in droves, and delay or cancel expansion projects, in an attempt to preserve cash flow. Whilst the current economic cycle has hit the mining sector hard, it is an opportunity for companies to take stock of their existing operations and plan for the future. As mining companies grapple for scarce capital resources, it is inevitable that industry consolidation will ensue. This presents challenges and opportunities for both buyers and sellers alike, looking to expand operations, or sell off assets to raise cash.

Jan 1, 2009

Resources and reserves are critical inputs into the determination of an operating mineÆs financial results and balance sheets, but how well understood is this fact. Do the investors, directors, accountants and geologists/engineers responsible for preparing or relying on relevant aspects of the end results properly understand the inputs and outputs and the associated risks that may be established. The first step is to understand how financial reports are impacted. The most obvious, and best known, impact is in the calculation of depreciation and amortisation charges against long term assets. In addition, however, there is a requirement to regularly determine whether asset book values are impaired û this is nearly always performed globally by the preparation of a discounted cashflow model for a mine which is usually based on a mine life as determined from the resource and reserve statement û the particular driver here is normally the short and long term production plans. A key aspect of the short term production plan is that it would normally not assume that the reserve and resource statement implies consistent grade, stripping ratios, etc. However, outside of the early years of a plan, more generic assumptions of these variables are often made in conjunction with the reserve and resource statement. Depending on the timeframe of the detailed production plans, this can have a large impact on a projectÆs net present value. Other financial balances that may also be impacted include restoration and rehabilitation provisions, retrenchment provisions and deferred or equalisation stripping accounts. The age old question of whether all reserves should be used or whether some or all of the resources should be included for financial reporting purposes has never been adequately resolved. It is our view that there should be no prescriptive answer to this question but judgement of all professionals involved in the process needs to be included. Furthermore, the company needs to be able to support their conclusions with well thought out and appropriate answers. This may not be in line with the approach that certain accounting standard setters may be proposing or taking, and this paper will outline the current status of global requirement and the likely future directions. Whether reserves or resources are utilised, does not change the key requirement that those preparing or using reserve and resource statements need to understand key aspects. For example: geologists/engineers do they know how reserves or resources will be used? have they imparted information on variability of key drivers such as grade or depth or dilution? do they know that major financial/business altering decisions may be made based on the analysis? accountants do they understand where the numbers have been derived from and the assumptions that may have been made in their determination? do they understand the degree of accuracy (or inaccuracy) that may exist particularly with resources)? do they understand the history of resource reconciliations and what it may mean for the future? directors do they understand the processes undertaken by the company to prepare the financial report and the interaction between the geologists/engineers and accountants? do they understand the potential sensitivity of results to the input variables? Financial reporting is extremely reliant on the use of the reserves and resources, however, the geologists/engineers, accountants and directors do not always understand the interactions between themselves which may lead to misleading public reporting. More education and communication between various parties is needed.

Jan 1, 2002

By M I. Pownceby, C M. MacRae, A Torpy

Electron probe microanalysis (EPMA) and quantitative X-ray diffraction (QXRD) techniques are capable of providing high-quality quantitative information regarding the phase mineralogy and distribution of alumina within iron ore samples. The techniques, however, use different methodologies in determining the mineralogical information (ie structural versus chemical), which introduces some limitations. In this study, EPMA was used to identify and quantify the deportment of alumina within mineral phases in iron ore samples (-1 mm crushed) sourced from different suppliers. Results were directly compared with quantitative mineralogical data derived from QXRD to provide an evaluation of the relative merits of both techniques. The four ores studied contained alumina either in the form of gibbsite, aluminosilicates (eg kaolinite), or associated with goethite.For minor phases, gibbsite and kaolinite, the abundance trends measured via QXRD were generally reflected in the EPMA data. Agreement was less satisfactory for the more abundant goethite phase (both low- and high-Al forms). The discrepancy may be the result of sampling issues arising from textural features such as grain size, and also a systematic overestimate in the amount of Al-rich goethite when hematite and Al-bearing phases are finely intermixed and the EPMA step size is coarse. A second difference in the EPMA results compared to the QXRD data was in regard to quantification of low-Al and high-Al goethite phases. The sensitivity of the chemical-based EPMA was better for distinguishing between high- and low-Al goethite although the results remain overprinted by potential errors introduced via sampling.Care should be taken when directly comparing results from each method, although in general the data should be considered complementary, as each approach provides slightly different results and interpretations regarding the overall mineralogy.CITATION:Pownceby, M I, MacRae, C M and Torpy, A, 2017. A comparison of X-ray and electron-based analysis techniques for characterising the mineralogy and alumina distribution in iron ores, in Proceedings Iron Ore 2017, pp 593–598 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

Reverse Cationic Flotation of Iron Ores - Floatability of Amphiboles at Depression of Iron Oxides by Starch

Sep 13, 2010

By G D. Matthews, M E. Haylett, S Khosrowshahi, A Weeks

In narrow orebodies the use of ordinary kriging (OK) may pose certain limitations when used for grade control modelling. The smoothing effect of kriging, by its very nature, cannot retain or accurately characterise the dispersion (variability) that is inherent in gold deposits. This dispersion is a critical component of determining the desired level of ore loss and dilution.Fixed block model positions used in OK, and all estimation approaches, within a grade control process may never align with the ‘true’ ore boundary. This may lead to excessive ore loss and dilution, especially within narrow lodes.Using a risk-based approach to ore block design based on the geostatistical method of conditional simulation (CS) can highlight the differences achieved when an alternative method to OK is used for grade control modelling. By using a mesh of nodes and the application of a ‘transfer function’ to the simulation models, the position for ore contacts can be better assessed than when using fixed blocks in OK. Therefore, the value of various ore block boundaries can be better analysed by objective assessment of ore loss and dilution for a given minimum mining selectivity (selective mining unit or SMU), even in narrow lodes.A case study of a narrow vein gold deposit, comparing the results from an OK model and a CS model shows that whilst both models show similar trends – waste, low-grade, and high-grade regions are the same in both cases – the simulation model can provide greater insight for optimal definition of the mineralisation boundary.CITATION:Haylett, M E, Weeks, A, Matthews, G D and Khosrowshahi, S, 2014. Ore block design in narrow vein gold deposits – estimate or simulate?, in Proceedings Ninth International Mining Geology Conference 2014 , pp 421–424 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

By P N. Holtham

As part of a long-term study of titanium minerals processing being undertaken by the Julius Kruttschnitt Mineral Research Centre (JKMRC), techniques have been developed to measure the electrical properties of the various minerals. The measured values will be used to model the behaviour of the various minerals in high-tension roll and electrostatic plate separators. The resistivities of ilmenite, rutile and zircon from a number of Australian producers have been measured by applying a DC voltage across a test sample and measuring the resulting very small current flow. By appropriate design of the measurement cell and attention to the experimental procedure, reproducible resistivity values have been obtained, ranging from 106Ωm for ilmenite to 1013Ωm for zircon. However, the conditions of measurement are radically different from those under which electrical separation takes place. It is not certain that the measured values reflect the resistivities seen under high-tension separation, during which the particles are subject to a high intensity corona field. Consequently, an alternative technique for measurement of resistivity under conditions of corona bombardment has been developed. It is based on the experimental procedure of Castle and Yelle (1979) used to measure the resistivity of fly ash under the conditions occurring in electrostatic precipitators. This paper describes the development of the segmented ground plane measurement surface and a high-voltage switched resistor network which comprises the in situ resistivity apparatus. Results are presented comparing the measurements made under corona bombardment with those made using the DC measurement cell. The equipment has also been used to study the current distribution from a corona wire, as a function of high-tension voltage and wire-to-plane spacing.

Jan 1, 2001

By P R. L Browne

Study of geothermal systems in the Taupo Volcanic Zone (TVZ) has significantly advanced our understanding of the processes of epithermal mineralisation. The three main lessons learnt are: 1. knowledge of their chemical anatomy; 2. precious metal transport and deposition; and 3. hydrothermal alteration zoning. These are described in the context of ore formation and exploration.

Jan 1, 1997

By W J. Rankin

A study was carried out to compare the environmental impacts of a number of process routes for lead and zinc metal production from sulphide ores using Life Cycle Assessment methodology and based on average industry data derived from the literature. The processes investigated were:blast furnace production of lead; Imperial Smelting Process for lead and zinc production; and electrowinning of zinc with the mining and mineral processing stages common to all three routes. The effect of a number of process variables, namely ore grade, fuel source for electricity generation and efficiency of generation, on the environmental impacts was also examined. The environmental impact categories considered in the study were:total (or full cycle) energy consumption; Global Warming Potential (GWP); and Acidification Potential (AP). The results of the study show that when produced separately, zinc production is more than twice as energy intensive as lead production (viz 48 and 20 MJ/kg respectively), however when produced jointly by the Imperial Smelting process, the energy intensity of the two metals is not all that dissimilar (viz 36 and 32 MJ/kg respectively). The metal production and refining stage was found to make the greatest contribution to the overall environmental impacts for all three processes. The study also highlighted the importance of taking a life cycle approach when comparing the environmental impacts of different processes.

Jan 1, 2002

The range of environments which control the level of ground support required vary greatly in terms of rock type, rock structure and the mining method used. At the operating mines visited during this review the level of ground support was such that incidence of rock-fall- related accidents were rare. It was also found that methods existed to support most of the conditions encountered. The main problem areas were weak rock, major geological structures, areas of heavy jointing, high development density and areas affected by high mining-induced stresses and blasting. With stope support the level of success was much lower than that achieved in development; the larger spans and more rapid changes in geometry of open stopes compared with cut and fill stoping (where cables were originally used) led to significant problems. Before a useable design method for cable support of stope walls and pillars can be obtained the precise failure mode of the walls and pillars, and the interaction of the support and the rock mass must be investigated.

Jan 1, 1982

By R L. Chaney, M Mahoney

Mine and ore beneficiation wastes and smelter contaminated soils often cause phytotoxicity and threaten adverse environmental effects if not remediated. Science has clarified both the risks from soil metals and methods to alleviate those risks that can be applied at low cost. Phytoremediation is a family of plant and agronomy based technologies to deal with environmental aspects of sites requiring remediation. If valid risk assessment indicates that metals comprise risk, phytostabilisation may be used to alleviate that risk for most contaminated sites. In particular, Zn-Pb, Cu and Ni mine and smelter sites are readily remediated by making the soil calcareous and fertile, with added organic and metal sorbent amendments that include soil microbes to ‘revitalise’ the soil. In each case, the soil fertility and causes of phytotoxicity should be clarified by agricultural soil extractions, and the combination of amendments required to improve fertility and reverse phytotoxicity identified and found locally. In contrast with phytostabilisation, phytoextraction/phytomining uses rare metal hyperaccumulator plants and agronomic management to maximise annual phytoextraction of soil elements into plant shoots for harvest, ashing and use as a metal ore. Plants that accumulate more than two per cent Ni in shoots, and yield 10–20 t ha-1 dry biomass yield 200–400 kg Ni ha-1, which has value greater than all common agricultural crops. Considering the value of elements, existence of hyperaccumulator plants and demonstrated agronomic management for Ni phytomining, it is clear that mine sites and Ni mineralised subore-grade serpentine soils can be phytomined economically as an agricultural mining technology. A team developed agronomic methods and improved cultivars of Alyssum, which can be profitably grown on temperate zone Ni mineralised or contaminated soils. Plant species for tropical ultramafic soil materials have been identified. Phytoextraction is also strongly needed to remove Cd from rice soils to prevent human disease from soil Cd.CITATION:Chaney, R?L?and?Mahoney, M, 2014. Phytostabilisation and phytomining – principles and successes, in Proceedings Life-of-Mine 2014 , pp 3–16 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

Study on Flotation of the Low-Grade Magnesite Ore

Sep 13, 2010

How Particles Stick to Bubbles - The Influence of pH and Hydrophobicity in Flotation

Sep 13, 2010

By K Broadley

Risk and dispute resolution are linked. Dispute resolution techniques are brought to bear on a dispute - which is an outcome of a risk being wholly or partially realised. There has been an increasing awareness by business of risk as a component of doing business. There is an accompanying awareness of the need to manage risk - including legal risk. Many companies have undertaken a systematic review of their potential risks and endeavoured to put in place systems to help to avoid or manage risks. A legal risk management program will not prevent disputes arising. However, such a program should prescribe how that dispute will be managed. The management of the dispute will involve consideration of the dispute resolution procedure to be adopted. The most appropriate processes will take into account the practical, personal and commercial considerations surrounding the dispute and be as efficient, cost-effective and user friendly as achievable in the circumstances for the benefit of all the parties. Carrying on business in South East Asia, whether as an explorer or a mining operator, brings additional considerations to bear in legal risk management and the dispute resolution process. A significantly different perspective is required due to the varying nature of the legal systems in many South East Asian jurisdictions. These jurisdictions often have relative uncertainty as to the law. This impacts on the dispute resolution processes and also raises further timing and cost issues. The authors contend that this is all the more reason to endeavour, as practically as possible, to adopt a legal risk management and dispute resolution profile which will provide business with the greatest prospects of maintaining control of the dispute resolution process. This presents a greater chance of a successful outcome to the dispute. In these times of increasing pressures on profitability because of low mineral prices, all costs of a minerals business are being reviewed. In such times, a significant legal dispute may have even greater potential to adversely impact on the companies concerned, together with the careers of the people involved. In this paper possible approaches to managing disputes and a case study a legal dispute in which Freehill Hollingdale and Page were involved are discussed. The dispute concerned an international mining company developing a gold mine in Indonesia and one of its contractors in Indonesia. Described is how that dispute was resolved. This achieved a very satisfactory result for the client - all things considered. Given the æadditionalÆ problems associated with ascertainment and enforcement of ærightsÆ in South East Asia, the longer the parties can retain control over their dispute the better off they will be. For this reason, the authors set out in this paper the main additional dispute resolution tools available - that are appropriate for use throughout South East Asia.

Jan 1, 1999

Study on Treatment of Wastewater Containing Heavy Metal Ions Using Modified Oceanic Cobalt-Rich Crusts

Sep 13, 2010