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By Taylor GP

Mt Kasi in Fiji is a high sulphidation style of gold deposit exposed at a high crustal level. Individual alteration centres are localised at the intersection of cross structures within a through-going structural corridor, the Mt Kasi Fault System. A two stage alteration/ mineralisation model suggests that much of the high sulphidation alteration is derived from the initial rapidly moving gas-rich portion of the hydrothermal fluid. The gradual cooling and neut-ralisation of hot acid fluids by mixing with oxygenated ground waters forms the characteristic zoned alteration assem-blages which grade from cores of residual silica through silica-alunite to peripheral clays. The liquid-dominated phase of the hydrothermal fluid brecciates the competent, altered rocks and deposits sulphide mineralise-ation within the breccia matrix. High gold grades occur in the matrix-rich breccias and decline from the hydro-thermal fluid upflow to outflow zones.CSAMT (controlled-source audio magneto-tellurics) geophysics has been used to define the geometry of the alteration centres while strike slip movement on the major structures accounts for the dilational structural environment in which the ore hosting breccias form.

Jan 1, 1994

Esso-BHP have installed a Production Supervisory Control System that is presently controlling the offshore oil and gas facilities on the Barracouta and Marlin platforms from an onshore master station. This control is achieved with a computerized master station onshore which uses a UHF radio system for telemetry and control. The system is designed to control, monitor, and gather data from a large number of oil and gas production platforms and has flexability to handle future variations in operating conditions. Thn -etom ..ill kn nvt,,ndnd to thn I-lalihn+ rJ,+f, rr , Into +hie -- -A +n the lei...,fieh .,lo+fnrmc A.,;- 1071

Jan 1, 1970

Magnesium-rich olivine is used as an additive in LKABÆs iron ore pellets in order to improve the high-temperature properties of the finished products. Olivine is only added to the pellets that are manufactured for ironmaking in the blast furnace process. The olivine comes from Minelco/LKABÆs mine at Seqi in Greenland. This dunite complex of Archean age contains about 95 - 98 per cent olivine. The grain size is typically 1 - 3 mm but much larger euhedral olivine crystals are common in the porphyritic type. The serpentinisation is absent or weak. The most common minor minerals are chromite, chlorite, talc, phlogopite, amphibole and pyroxene. The crushed olivine is transported to LKABÆs pelletising plants in Northern Sweden. After grinding, small amounts of olivine are mixed with the magnetite concentrate. The concentrate is rolled into green balls, about 10 - 14 mm in diameter. The moist green balls are transferred into the pelletising machine where the maximum temperature is about 1250¦C. The residence time in the pelletising machine is about one hour. Olivine is used in order to get pellets with better high-temperature properties. This paper deals with the olivine alteration during the pelletising process and the behaviour of magnesium following the decomposition of magnetite. The reactions are quite complex in the pellets because the physico-chemical conditions vary considerably in the process from one process step to another, and in the pellet bed from the top to the bottom. Some olivine particles in the finished product show very slight alteration, some particles are completely decomposed. The formation of the iron-rich coronas around the olivine particles is the most typical alteration. In the finished pellets the magnesium is mainly distributed between the following phases: unaltered olivine, coronas, Mg/Fe-ferrite and silicate slag.

Jan 1, 2008

By D Brereton, C J. Moran

In this era of rising focus on the social and environmental costs and benefits of mining operations, the valuation methodologies used to assess such impacts become increasingly important. Within an industry dominated by an engineering culture that places emphasis on net present value (NPV) calculations using high discount rates, difficulties often arise when attempting to justify projects with longer-term, harder to quantify benefits. This is particularly so when these benefits fall in the social and environmental domains and involve other stakeholders. In this paper, we summarise the results of a recent literature review on this subject, which focused on the valuation of æBeyond ComplianceÆ initiatives in the mining sector. We discuss a range of approaches including the quantification of hidden internal costs, financial methods of incorporating risk into calculations, the integration of quantitative and qualitative information, and also the valuation of æexternalitiesÆ or costs and benefits borne by others. We then use a series of examples relating to the management of water in the minerals industry to illustrate how some of these approaches could be applied. There are high-level commitments from both individual companies and groups such as the ICMM to incorporate sustainable development criteria into decision-making processes within the industry. We conclude the paper by arguing that, to meet these commitments, there is a need for the industry to adopt a broader range of valuation methodologies than appears to be the case at present.

Jan 1, 2006

By Barber C, Buselli G

Detailed monitoring of point sources of groundwater pollution is expensive due to the high cost of drilling monitoring boreholes. Whether groundwater pollution is due to mining, industrial or domestic waste disposal, a universal difficulty when monitoring groundwater contamination is the placement of boreholes to adequately define the extent of the pollution plume. This paper reports groundwater 'resistivity variations determined from transient electromagnetic soundings at a domestic waste disposal site north of Perth in Western Australia. Together with available hydrogeological and water quality data, the geophysics provides a broad "plume scale" picture of groundwater contamination. A simple three dimensional model of plume development, which takes account of the dimensions of the wastes, has also been developed and shows good agreement with the spread of contamination indicated by the geophysics for relatively small values of the dispersivities. Better estimates of these parameters are still required. The work indicates that a combination of geophysics and modelling with ground-truth data from groundwater quality monitoring of boreholes is required to avoid difficulties in interpretation of data and to better define the extent and migration of pollution in Groundwater.

Jan 1, 1988

By A Valero, G M. Mudd

There is active debate and research around the most suitable indicators to assess the sustainability of mining. The most common approach is to report a range of data for a given mine site (or less preferably, a company total), such as inputs, outputs, benefits and potential costs. The most popular protocol in use (and growing rapidly) is the Global Reporting Initiative (GRI). However, these measures are numerous and still do not allow a single over-arching indicator to be developed. Other measures, such as known mineral resources over time, do not account for critical challenges such as declining ore grades, increasing wastes and poorer quality ores or more difficult mineralogy. By adopting a thermodynamic approach to sustainability, through the concept of æexergyÆ, it is possible to incorporate into a single measure the effective quality of mineral resources. Exergy involves the assessment of the minimum energy costs involved in producing a mineral resource with a specific chemical composition and concentration from common materials in the environment. The exergy of a mineral resource is evaluated from mineralogic composition, concentration (or ore grade) and, of course, quantity, by multiplying the unit exergies with the tonnes of the resource produced (or consumed). Since exergy is a thermodynamic quantity (ie energy or joules), it is additive across different minerals, such as iron ore to gold to copper or even oil and gas or coal û making it an ideal indicator to assess mineral resource sustainability at the industry scale rather than the individual mine scale. This paper briefly outlines the theoretical basis for exergy, and then presents a range of commodity case studies showing the application of exergy to the Australian mining industry. Overall, the usefulness of exergy is clearly demonstrated for use as a broad indicator of the sustainability of mineral resources at the national or even global scale.

Jan 1, 2009

By L S. Shekhawat, M P. Roy, R K. Paswan, P K. Singh, A Joshi

Blasting in the mining industry is being transformed, and can no longer be treated as an art or a practice purely dependent upon experiences of individuals. Examples of key drivers that have demanded consistent and more accurate blast results are initiatives to control pit-wall damage to help mine steeper pit slope angles, to control damage to underground opening operating in close vicinity of the open pit mine. Such situation exists at Rampura Agucha open pit lead zinc mine, which is producing 5.7 Mt/a of ore and has started its underground part, which is slated to produce initially 2–2.4 Mt/a and 4.5 Mt/a in the near future. The open pit mine is currently working at 326 m depth and is designed to reach 421 m deep. It has been planned to operate the underground mine maintaining 50 m parting from the planned ultimate level of the open pit mine.Presently, open pit and underground mines are being operated simultaneously. The present average depth of underground working lies between 370 and 410 m below the surface level. Sometimes explosives up to 95 978 kg are being detonated in a blast round in open pit mine. These blasts are often apprehended as a danger to the safety and stability of underground openings. It was decided to document the impact of open pit blasting in the openings of underground workings, so that preventive measures may be taken for the safety and long-term stability of the underground mine. The impact of 86 open pit blasts has been documented in the underground openings and 258 blast vibration data has been recorded. The vibrations were recorded simultaneously in the roof, side walls and at floor levels. The highest levels of vibrations were recorded in the roof and the lowest levels at the corresponding floor levels. The pillars experienced lower level of vibrations than the roof. Blast designs were optimised at open pit mine to control vibration in view of long-term safety and stability of the underground openings. The vibrations generated due to detonation of explosives with shock tubes and electronic delay detonators have been recorded in underground openings for comparative assessment. Ground vibration recorded at roof, pillar and floor were analysed separately and threshold value of the vibration for the safety of underground workings has been determined based on the rock mass rating of the roof rock.CITATION:Singh, P K, Roy, M P, Paswan, R K, Shekhawat, L S and Joshi, A, 2015. Protection of underground mine structures due to adjoining open pit mine blasting, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 279–288 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By G Caddy, M Middleton, S Kerec, R Keil, J Tsalapatis

Arrium’s OneSteel Whyalla Steelworks in South Australia is a fully integrated plant which operates a single blast furnace. The key operational objective has been to maintain high process availability and stability while maximising the process efficiency and the produced hot metal quality. All ferrous raw material input feeds are sourced exclusively from company iron ore deposits in the nearby Middleback Ranges. The Whyalla blast furnace has mostly operated using a combination of a high percentage of pellet feed, produced in Whyalla, together with screened lump ore.The unique ironmaking challenge has always been to extract the maximum value from the ferrous burden feed available locally. In earlier times, high-grade hematite lump ore was available for both screened lump ore and pellet production. Blast furnace trials from acid to fluxed pellet feed commenced in 1977. The furnace pellet feed has been wholly fluxed since 1981. Many pellet/lump ore feed mixes and significant pellet chemistry composition design changes have been made over the years. These changes have been aimed at best balancing the ferrous burden availability/cost and the optimum reducibility/high temperature melting behaviour of the charged ferrous feed within the blast furnace. In more recent times since 2007, the Whyalla blast furnace operation has transitioned from a hematite based pellet feed to a magnetite based pellet feed while there is an ongoing contest dealing with diminishing absolute quality/increased variability raw material feed inputs.The paper will detail key elements of the Whyalla blast furnace operational philosophy with regards to ferrous feed use and process optimisation. The blast furnace ferrous feed design considerations will be discussed, together with the test work performed, the operational and slag design transition strategies employed and the process results achieved.CITATION:Tsalapatis, J, Middleton, M, Keil, R, Kerec, S and Caddy, G, 2015. The use and optimisation of ferrous feed at the Whyalla Blast Furnace, in Proceedings Iron Ore 2015, pp 377–384 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By Dobos SK

The Black Ridge Gold Deposit is located in the northern part of the Clermont Goldfield, which is situated at the boundary of the Bowen Basin and Anakie Inlier, Queensland. The goldfield comprises a series of NNW-trending semi-isolated basins, which are tectonically aligned with the Denison Trough, the west-most division of the Bowen Basin (Fig. 1-1).The main stratigraphic units in the deposits in younging sequence are the Anakie Metamorphics, the early Permian Blair Athol Coal Measures, the late Permian(?) White Section, and the Tertiary basalts which are regionally widespread, and intruded by abundant mafic and felsic plugs.

Jan 1, 1990

The ASC has a dual role of business facilitator and law enforcer. Only certain types of expert report are of interest to the ASC. The powers of the old Companies Code and the Corporations law are compared. NCSC Policy Release 149 was dependent on the prescriptive powers given to the NCSC in the Companies Code. The Corporations Law does not give the ASC power to prescribe the contents of expert reports. The requirement now is for all necessary information. Research evidence is that some investors want simpler prospectuses while others need more detail. The ASC's examination of expert reports is after registration of primary documents. This leads to a necessity for experts to maintain adequate records.

Jan 1, 1994

By W Wu

The prospect of discrete element modelling (DEM) being used as an everyday design tool for transfer chutes in the iron ore mining industry is becoming more and more probable. However, much care needs to be taken to ensure accurate results are obtained. Whilst there are many publications in industry portraying the potential of DEM, there is little evidence of where it has been validated against a real set of experimental results. The purpose of this investigation was to gauge whether the incorporation of the physical properties of a specific bulk material at the DEM pre-processing stage can yield visually and numerically accurate simulations for a simple flow case. Effects such as irregular particle shapes, varying frictional properties and coefficients of restitution, all found through experimentation were investigated. Video analysis was used to compare simulations to real flow cases. It was found the most critical attributes in determining the accuracy of the simulations were particle shape and wall friction. Keeping the particle-to-wall friction factor constant was not sufficient to describe the flow accurately. But by introducing the varying effects of wall friction with consolidation stress, the correct results were simulated.

Jan 1, 2007

The Peko copper orebody is associated with a body of magnetite rock which it has partly replaced. The primary ore averages about 9 per cent. copper and 4 dwt. gold per ton and locally IS much richer. It consists essentially of chalcopyrite and unreplaced magnetite, with lesser amounts of pyrite, marcasite, pyrrhotite, cobaltite, bismuthinite, native bismuth and native gold. The earliest formed mineral is wolfram, and the latest formed is goethite, so that the temperature of deposition ranged from about 5000 C. to 1650 C. or lower.Oxidation extends to 270 ft., which is 100 ft. below the present water level. The oxidized ore consists of cuprite and native copper, and has replaced more or less massive chalcocite of a former zone of secondary sulphide enrichment. The present zone of secondary sulphide enrichment extends from about 270 ft. to 310 ft. depth.INTRODUCTIONThe Peko mine is about 6 miles south-west of Tennant Creek township in the Northern Territory, adjacent to a small outcrop of hematite rock that projects above an otherwise featureless "bull-dust" fiat.The copper-gold orebody being developed in this mine did not outcrop. It was first detected in 1950 by a surface diamond-drill hole (DDH.1), which intersected primary copper ore at a depth of 400 to 425 ft. This ore contained from 4 to 11 per cent. copper and 1 to 25 dwt. gold per ton. Since then a shaft has been sunk, and crosscuts and development drives have been opened on the 210..ft., 300-ft. and 400-ft. levels, which are also connected by winzes. Two diamond drill holes sunk from the 400-ft. level have intersected theorebody at about 450 to 460 ft., and a winze from the 400-ft. level intersected the lode from 445 to 500 ft. At this point it is 54 ft. wide, and averages 9 per cent. copper. More recently an inclined surface drill hole (Peko No. 1) has cut the lode at 856 ft. to 921 ft., equivalent to a vertical depth...

Jan 1, 1955

By Hill KC, Foster DA

Methods for ore reserve estimation are classified. The amount of information needed to asses ore reserves is analysed. Reference is made to gold sampling. Consideration is given to nugget effects and ore reserve estimation procedures where they are significant. Computer methods are discussed

Jan 1, 1997

By M Orunesu Preiata

The Odysseus Project is part of the high-grade Cosmos Nickel Complex that lies 30 km north of Leinster. The Odysseus definitive feasibility study (DFS) was approved by the Western Areas’ board in October 2018. Early works commenced in January 2019 with rehabilitation of the existing underground infrastructure. In June 2022 Western Areas was acquired by IGO Ltd. The project is now well advanced to meet its target of first concentrate. The project included the construction of a haulage shaft. The design of the hoisting equipment and the shaft barrel evolved from the initial DFS design stage to the final execution, as the data were made available from the initial investigation to the data gathered during execution (although this did not change from its initial concept). The design philosophy for the haulage shaft incorporated, from the beginning a multidisciplinary approach with inputs from three main areas involved in such projects, namely excavation techniques, geotechnical assessments, and infrastructure construction. This interaction is a fundamental component for the success of such a critical project. In fact, each of these three areas influences each other in a cyclical manner, triggering a continuous review of the project inputs and outputs, while maintaining the original project goals: the design of an infrastructure able to deliver the desired throughput. The throughput dictates the infrastructure that needs to be built, which in turn controls the size of the shaft. The key assumption applied to this is that the rock mass can accommodate the excavation void, and the excavation technique with its tolerances and limits that ultimately need to be verified back with the initial assumptions used for the infrastructure design. The aim of the paper is to present a case study of the experience gained with the Odysseus hoisting shaft and to propose a possible logic path for similar projects elsewhere.

Mar 29, 2023

Mine planning typically involves designing an operation to uncover coal with the minimum initial costs with reclamation planning and earthworks being done as an "add on" task. The landform is too steep to remain stable, has no drainage and frequently has areas of excessive acidity or alkalinity. Extensive earthworks are required to reduce grades to an acceptable level and create a drainage system. The flexibility available to the mining engineer to alter the post mining landscape clearly depends on the mining methods. Straight dragline stripping provides virtually no flexibility. However most mining operations over the term of current ten year plans have a substantial pre-strip component. It is this pre-strip material which has the potential to reduce the final reshaping earthworks. The reshaping operation itself is subject to some flexibility with various options being available to re-grade and provide drainage. The full utilisation of this flexibility to minimise earthworks cost should be the aim of reclamation design. ACIRL's current thrust in reclamation is aimed at the integration of mine planning and reclamation earthworks. This involves gathering all environment and agricultural criteria and designing the earth works necessary to produce an acceptable final landform. A key component of our work is the use of computer aided design (CADD) for the design of spoil piles, pre-strip dumps and spoil re-shaping. This approach has been applied to a number of mine sites with earthworks operations covering hundreds of hectares and hundreds of millions of cubic metres volume. We are continuing to provide that consultancy service and at the same time are involved in the development of more sophisticated software tools to apply to reclamation design.

Jan 1, 1991

By D Baas, D Bennett

This paper describes how Brisbane-based PanAust Limited develops process control strategies that are implemented at all operations and are used in functional descriptions for plant upgrades and new projects.The process control strategies are determined by operating management philosophies designed to maximise returns from the company’s assets.The approach is endorsed in the project planning and design phases to ensure facilities and equipment that form the major production assets are fit for purpose and capable of enabling the production managers and operators of the projects to maximise shareholder returns.PanAust’s process control approach has been to develop sets of process control standards which focus on two key areas. The first area covers hardware requirements and architecture, software objectives, control models and individual loop tuning methods. The second area defines control room layout, graphic standards and the alarm philosophy. The application of these standards in a new plant or upgrade decreases the time required to achieve design capacity and optimal performance.The PanAust process control strategy changes the operator’s role from one that controls a number of individual loops to one that sets the control objectives of the processing plant. To achieve optimal performance, all the process areas of the plant are analysed to identify opportunities to improve throughput, recovery and stability. Once a key opportunity is identified, a process control strategy is developed which defines the objective of the control, its functionality and how an operator will interact with it. After development of the control model the operators assist engineers to test and debug it. Once the model is robust, it can then be duplicated throughout the group and developed as a group process control standard.CITATION:Baas, D, Bennett, D and Walker, P, 2014. Developing process control standards for optimal plant performance at PanAust Limited, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 325–334 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

By A Fowler

The unpredictability of the location, grade and width of narrow-vein deposits presents difficulties for mine geologists and engineers attempting to estimate, schedule, forecast and mine their deposit profitably. This unpredictability stems not only from the grade distribution within a vein, but also the irregularity of vein geometry in three-dimensional (3D) space. Traditional deterministic methods of modelling vein geometry do not account for the inherent variability of the veins, resulting in significant errors when using limited drill hole information. This paper presents a probabilistic method of modelling narrow-vein deposits using sequential gaussian simulation (SGS), which can quantify this variability and improve production forecasts. Vein geometry, thickness and grade are simulated to provide a number of different equi-probable realisations that each honour the drill hole and face sample input statistics. An example is presented from the Augusta narrow-vein Au-Sb mine in central Victoria, where the simulation results are validated against the input data and survey pick-ups of the veins along ore drives.

Aug 22, 2011

By V Chamberlain, M Appeah Owusu, M Aniawu-Asumakah, A Anyimadu, R Peattie

This is an integrated geology and plant improvement study arising from the heterogeneity seen in mineralogy and gold association at the Obuasi goldmine in Ghana. This heterogeneity comes from the two ore types mined, the one being a sulphide ore, mainly composed of gold-bearing arsenopyrites. This gold is refractory and exhibits a strong relationship between gold and As. The other is quartz veins, that are high grade and free milling. The installed circuit consists of comminution – Gravity -Flotation – BIOX – Leaching and Adsorption processes. The opportunity tested involved improved mass pull - related flotation recovery of Au in the Sulphide stream; while balancing the need for a minimum Sulphide grade for the Bio-oxidation process, occasioned by the removal of 25 to 30 % of the (quartz) stream through preconcentration by Ore sorting. The current circuit is then utilized for the sulphide route, while a smaller grind-gravity circuit is utilised for the quartz stream in a relatively inexpensive way, followed by a common leaching and adsorption circuit. Added advantages of the strategy includes faster recovery of gold from the quartz stream, with less consumption of reagents from saving on flotation and BIOX reagents for this stream. Screening and Ore sorting was successfully tested with laser technology, achieving over 98% separation of quarts (containing up to 40% of the gold). The plant schedule of Ore, the suggested circuit design for the Ore sorting, the results obtained from the different flotation regimes, as well as consequent financial modelling have been presented and discussed in this paper. This illustrates the opportunity that arises out of a detailed analysis of material versus installed circuits, even if the gains in pre-concentration do not necessarily involve rejection of gangue material. An added opportunity for future investigation, briefly discussed but not tested in this paper, would be to maintain current mass pulls but with increase in throughput (by the space created by the sorted material). This will of course require the mining ability. It could also add LOM value by altering the cut-off grade.

Nov 10, 2020

By Scoble M, Peck J

This paper reviews the instrumentation and monitoring of blasthole drills and electric mining shovels at a surface coal mine in western Canada. The drill monitoring component involved the development and implementation of microprocessor-based hardware on Bucyrus-Erie 45R and 60R drills. Over a two year period 3800 metres of blasthole drilling were monitored The drill data was subsequently correlated with core and geophysical logs towards identifying unique and reproducible ranges of performance parameter data for the different rock types penetrated. Using this technique, the geology of the study area benches was characterized in detail. Once these same benches had been blasted, the performance of a P&H 2800XP shovel was monitored as it worked through the blasted ground. In this regard, the influence of different digging conditions on shovel performance were identified in a range of blast and geological environments within the study area. The precise nature of these environments was confirmed by a correlation with the interpreted drill monitored data and muckpile size distributions obtained from a digital photo-analysis study. The excavation of 500 000 bcm of waste was thus monitored and a digging index derived which reflected variations in muckpile diggability. The paper concludes by proposing an integrated monitoring approach which, as a first step, uses interpreted drill data for explosive loading. This capability would permit greater accuracy in explosives loading ie. charge placement within higher strength lithologies, while avoiding weaker units. The performance of an instrumented shovel would then be monitored as it works through the resulting muckpile. Interpretation of the shovel performance data would determine the overall quality of the blast in terms of a digging index (DI), providing an indication of the relative digging effort and the effectiveness of the blast design.

Jan 1, 1990

A comprehensive analysisof rock structures in non-oriented (axially oriented) drillcore is now available (Laing, in press). The system embodies new concepts which better equip the geologist and engineer to deal from the outset with optimising the acquisition of structural information in drillcore, logging, interpreting, and graphically presenting the results. The few existing techniques for determining orientations of structures are augmented by a wide range of new techniques, and all are brought together into two solution types by considering the underlying Euclidean geometries. Analysis of these solution types in terms of what data are required to implement each solution and what assumptions need to be made, leads to strategies which facilitate intelligent design of different drilling programs for blind and outcropping situations. Drillcorc is variably structurally fertile, depending on the number of different structures present. This concept fosters the selective logging only of the more fertile core. Drillholes are also variably fertile, depending on their orientational relationship to the structures in the host rocks. Structural parameters are either vectorial or non-vectorial. Vectorial structures parameters comprise normal structural orientations plus polar vectors like vergence, younging, shear sense and so on. They can be determined by one of two solution types: external solutions, which use an external reference structure to fix the drillcore and thus permit orientation of all structures within that core, and internal solutions, which use orientational data from a selected structure at three or more different drillhole orientation to determine the unique orientation of that structure, without reference to any external structure.

Jan 1, 1990