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By Crawford M

During the initial development of Mount Isa Mines power was supplied from a temporary power plant situated near the Man & Supply Shaft. The main power plant was placed in service early in 1931 and then comprised two Babcock and Willcox boilers, fired by pulverised fuel, and two British General Electric Company's turbo-alternators of 5,000 kW. each. Both plants have been described by A. F. McAskill in the Journal of the Institution of Engineers, Australia.From 1931 power demand progressively increased due to greater production, further mine development in the harder sulphides increased pumping for mine drainage and additions to mill and smelter until, by 1935, the plant was inadequate for further output commensurate with a reasonable safety margin.Coincident with the added power demand, operating conditions involved a fuel problem which could not have been anticipated. The ash content of the fuel supplied gradually increased from 13% to 16-5%, while the melting point of the ash decreased with higher pyrite content.Temperature conditions in the furnace required careful control to cope with ash formation and slag accretions.Consequently brickwork, excessively stressed on water walls, was constantly under repair, and required suspension periods of 50% of operating time for cleaning and overhaul.Load conditions varied continually, therefore the high heat liberations in the furnace, necessary to accommodate peaks in fluctuating output, resulted in ash fusion.

Jan 1, 1939

By F Radke, P A. Tilyard

Determination of the mineralogical location (deportment) of minor and trace elements (including credit and penalty elements) in base metal concentrates can indicate whether further processing is likely to (a) reduce the levels of the penalty elements, and/or (b) direct selected elements into other plant products, thereby increasing current concentrate grade or increasing payment for credit elements. To determine the deportment of elements requires knowledge of the proportions of the minerals present and their individual element contents. In addition, knowledge of the liberation and locking is important, as this can affect any possible further processing. Mineral proportions can be determined by a variety of methods including chemical analysis, point-counting, area-counting, QEM*SEM, image analysis and mineral separation. In the case of a Broken Hill zinc concentrate, several of these methods were used and gave consistent results.

Jan 1, 1998

By R Dunne, J Dodd, J Snyder, F Roberto

Energy costs are steadily increasing worldwide while the availability and quality of water are becoming contentious issues between the users (municipalities/households, agriculture, manufacturing and mining). Refractory gold ore treatment - pressure oxidation, biological oxidation and roasting (ultra-fine grinding, or UFG, will not be discussed here as this process only reduces the particle size of the feed prior to cyanidation) - requires substantially more energy and water quantity and quality are vastly different compared to the standard and simple flow sheets used for treating non-refractory ores This paper will provide an overview of the energy and water requirements for treating refractory gold ores, a topic which does not appear to have been considered previously in the literature.CITATION:Roberto, F, Snyder, J, Dodd, J and Dunne, R, 2013. Energy and water requirements in the treatment of refractory gold ores, in Proceedings World Gold 2013 , pp 527-532 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By S E. Wallah, D Hardjito, B V. Ran

The manufacture of Ordinary Portland Cement (OPC) is not only energy-intensive but also releases a significant volume of carbon dioxide (CO2) to the atmosphere. In addition, OPC in concrete often causes premature deterioration that affects the durability of concrete structures. This paper explores an alternative to OPC concrete called geopolymer concrete.The present research utilises low calcium (class F) fly ash as the source material to produce geopolymer concrete. Several factors that affect the mix design process such as mix proportion, curing time, and curing temperature have been studied. In addition, the long-term properties such as drying shrinkage, creep, and exposure to sulfate attack are also being investigated.The test data presented in this paper reveal that geopolymer concrete possesses high compressive strength, undergoes very little drying shrinkage and moderately low creep, and shows excellent resistance to sulfate attack. The result is extremely promising and demonstrates the sustainability of geopolymer concrete as a construction material for a sustainable future.

Jan 1, 2004

By J Arola, B Kettunen, W M. Bond

Separation of fine and coarse particles as separate streams prior to flotation, and their differential treatments, could substantially increase recovery and reduce collector consumption. A series of simulations was carried out to quantify the benefits from plant scale implementation of such a treatment at the Ispat Inland flotation circuit (Minorca mine). The study involved detailed plant sampling and sample analysis to generate the data needed for simulation studies. Samples were taken from all the streams from flotation feed to final concentrate, as well as cell lips and cell pulp. Sampling was repeated for the second ore blend that was processed by the plant during different periods of a year. Sample analysis involved sieve analysis and size by size chemical analysis for total iron, magnetic iron and silica. Raw data were mass balanced, and flow rates within the circuit were calculated. Mass balanced data were used to calculate model parameters representing the existing conditions. Usim Pac was used for both mass balancing and simulation studies. Available pilot and bench scale data were utilised to define the modified flow sheet and expected performance. The simulated flow sheet included classification of flotation circuit feed by hydrocyclones. While the coarse fraction followed the existing flow sheet, the fine fraction was sent to a magnetic separator. Magnetic and rougher flotation concentrates were combined to form the final concentrate. Two simulations for each blend were carried out. The first one assumed that there would be no change in size by size kinetic behaviours of both gangue and magnetite due to this modification. This was named as the worst case scenario, in which particles had a longer residence time due to reduced flow rates within the flotation cells. The second scenario anticipated that there would be an increase in recoveries of gangue and magnetite going into froth launder due to more efficient use of collector in absence of fines. Results showed that pre-classification of flotation feed could improve the flotation recovery by 0.3 - 0.5 per cent, with the major benefit being significant reduction (40 - 60 per cent) in the amount of collector used.

Jan 1, 2005

By P Dunn

Following civil war in Sierra Leone, London Mining Plc obtained the mining license in 2006 and commenced activity to redevelop the Marampa mining and processing operations. The Sierra Leone Marampa mine is a brownfield development effort, having been operated by a few companies since the 1930s until low iron ore prices forced closure. Peak production of the preceding operations was approximately 2.5 Mt/a in the 1960s. There are two virgin ore deposits of interest for development as well as a resource comprised of tailings accumulated from previous operations. The Marampa tailings operation (Phase 1a) is being implemented first with a 1.8 Mt/a plant producing 66 per cent Fe sinter feed, expandable to 3.6 Mt/a in a Phase 1b. The first phase is currently under construction with start-up expected in the third quarter of 2011. Further expansion (Phase 2) that includes the development of the virgin deposits is currently under prefeasibility study and targets a final 16 Mt/a concentrate production. Outotec partnered with London Mining to develop the magnetic separation flow sheet using SLon VPHGMS machines to process the Marampa tailings (haematite) material. The flow sheet development process started with sample characterisation and detailed parametric investigations to evaluate SLon performance. The final flow sheet configuration, including expected circuit recoveries and concentrate quality, demonstrates the performance of the SLon VPHGMS circuit for iron ore tailings.

Jul 11, 2011

By Colston M. B, Johnson I. D

The importance which matters of social welfare and environmental quality have assumed recently is the underlying theme of this paper. Demands for infrastructure reflect the change in emphasis from economic and technological development to those issues which affect the total well-being of the community. To put the importance of social change in perspective, examples are cited and a theme is developed which underlines the relevance of changes in public attitude and in government policies on mineral exploitation and related development and on the regimen of associated infrastructure sought. Planning on a long term or strategic basis and on a broad scale is put forward as an effective means of identifying changing social attitudes for the purpose of framing government and corporate policies. As a prelude to a section in which a description is given of a novel 'services baseline' concept and its use in the assessment of the current backlog of services

Jan 1, 1977

By J Zhou

Gold in sulfide ores is associated predominantly with sulfide minerals and occurs as both microscopic and submicroscopic particles. In non-refractory sulfide ores, gold occurs mainly as coarse- and medium-grained particles. Minute inclusions and submicroscopic gold usually account for a minor portion. In contrast, gold in refractory sulfide ores occurs mainly as minute particles and submicroscopic gold, and microscopic gold usually accounts for an insignificant portion. In gold ores containing carbonaceous material, the preg-robbing nature of carbonaceous material may impose challenges on gold extraction and cause gold losses. To extract gold from refractory sulfide ores, the ore needs to be finely ground and preoxidation is often required. Sulfide host minerals must first be oxidised to create a porous structure through which the cyanide leach solution can penetrate to reach the colloidal gold particles. The oxidation is traditionally achieved by roasting, autoclaving or bacterial oxidation. In carbonaceous sulfide ores exhibiting a preg-robbing nature, the carbonaceous material needs to be treated by roasting, autoclaving or other means to minimise the preg-robbing effect. As a predictive and troubleshooting tool, the gold deportment study plays an important role in gold metallurgy. It determines the deportment of gold in an ore or mill product and identifies the mineralogical issues that may affect or may have affected gold extraction. The information acquired from a gold deportment study can be used to assist in process selection, flow sheet development, recovery improvement and reagent optimisation.CITATION:Zhou, J, 2013. Deportment of gold in sulfide ores and implications for gold extraction, in Proceedings World Gold 2013 , pp 433-442 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By J Boshoff, D Reid

It has been recognised worldwide that the liquefaction risk of unconstrained tailings stacks or cyclone underflow embankments requires careful consideration. The stability of a tailings deposit where the perimeter embankments are made up of hydraulic fill is often governed by post-liquefaction stability.Cyclones are frequently used around the world to classify tailings into a coarse underflow for building a tailings impoundment wall and a finer fraction that is disposed of into the basin. The shear strength of the tailings that form the outer embankment of a tailings storage facility (TSF) and the location of the phreatic surface are the two most significant factors influencing the structural integrity of the facility. The coarse underflow is placed in such a way as to contain the overflow, which is finer, has low strength and is often poorly consolidated.A cyclone field trial was undertaken at a gold mine in Western Australia to assess the feasibility of using the cyclone deposition method to optimise and increase the capacity of an existing tailings cell. The aim of the cyclone trial was to collect information to demonstrate to the client and the regulators that cyclone deposition was a feasible option for raising TSF embankments. The cyclone trial provided an opportunity to assess the cyclone under field conditions and the quantity and quality of the underflow fraction produced on-site. A variety of methods were used to assess the flow liquefaction susceptibility of the tailings underflow sample produced during the cyclone field trial.The field trial, laboratory testing and analysis will be discussed in this paper.CITATION:Boshoff, J and Reid, D, 2015. The resistance of cyclone underflow material to flow liquefaction, in Proceedings Tailings and Mine Waste Management for the 21st Century , pp 151–156 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 27, 2015

Production scheduling of open pit mining is a key area as it deals with the management of operating cash flows of mining companies. The efficiency of long-term schedules is usually assessed with economic criteria such as net present value (NPV), discounted cash flow rate of return (DCFROR) and payback period, which are not sufficient on their own for revealing the complex picture of the decision-making process.This paper offers a thorough analysis of the most important contemporary criteria of long-term production scheduling, as way to provide the mining practice with a new approach to the decision-making process. The list of criteria includes technological, economic and probabilistic ones. A detailed case study is provided aiming to illustrate the applicability of the criteria for comparing the scheduling approaches regarding the economic interests of a mineÆs owner and contractor. The results obtained can be used for revealing new trends in the current methodology of open-pit production scheduling optimisations.

Sep 26, 2011

By H Benzer

Grinding clinker to finished cement consumes more energy than any other comminution process. World production of cement in 2009 was 2840 million tonnes and the energy required for comminution was 40-60 kWh/tonne depending on the clinker characteristics and the fineness of the finished cement. Machines used include single and multi compartment ball mills, HPGRs, vertical roller mills, centrifugal air separators, V separators, screens and crushers. The circuit most commonly used consists of a closed circuit HPGR followed by a single compartment ball mill and an air separator, and in operation the variables are adjusted to obtain maximum throughput with no loss of quality of the separator fines.A common objective in cement plants is to reduce energy consumption without affecting the particle size in the finished cement and simulation is used as one procedure to achieve this. Models are now available for all the machines commonly used in clinker circuits and circuit optimisation studies using simulation have been carried out in many plants leading to decrease in energy consumption per tonne of cement. In this paper the models used will be discussed briefly and several case studies will be reviewed which will highlight the effect of change in ball size in a two compartment mill, the role of the HPGR in an HPGR – ball mill – air separator circuit, and the use of a high intensity vibrating mill for producing finished cement with high additive ratio.

Aug 8, 2011

By K Williams, M Pender, T Honeyands, T Krull, D McCallum, R Holmes, R Orense

Bulk cargoes, including iron ore fines, must be shipped according to the rules agreed by the member states of the International Maritime Organization (IMO). One critical safety measure is the transportable moisture limit (T?ML) required for Group A cargoes (cargoes that may liquefy). A number of shipping incidents involving iron ore fines from India, where liquefaction of the cargo was suspected to be the cause, have brought the issue of iron ore fines T?ML into the spotlight. Extensive research has been undertaken by the major iron ore producers from Australia and Brazil to support the IMO in developing regulations for the shipment of iron ore fines. To this end, iron ore companies sponsored the AMIRA P1097 project to establish a modified T?ML test approach specific to iron ore fines. The project was undertaken by TUNRA Bulk Solids, CSIRO’s Centre for Bulk Solids and Particulate Technology and the University of Auckland, with project leadership provided by Creative Process Innovation. This program of work supported test work findings from the IMO Iron Ore Technical Working Group, which reported its findings in September 2013.The purpose of this paper is to present the major research findings from the AMIRA P1097 project, which includes a review of the original T?ML methods, highlights of the research that supported the new iron ore fines T?ML method and an outline of current iron ore T?ML requirements.CITATION:Williams, K, Honeyands, T, Holmes, R, Orense, R, Roberts, A, Pender, M, McCallum, D and Krull, T, 2015. Maritime bulk cargo transportable moisture limit requirements for iron ore shipments, in Proceedings Iron Ore 2015, pp 399–410 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

Mining operations in the Obuasi mine of AngloGold Ashanti Limited began in 1897 using mainly gravity concentration and amalgamation to recover the gold from predominantly high-grade quartz ores. The mine is primarily an underground operation, although some surface mining still takes place. Ore is currently processed by two main treatment plants: the Sulfide Treatment Plant (STP) for underground ore and the tailings treatment plant for tailings reclamation operations. STP was commissioned in February 1994 to treat 180 000 t/m of double refractory gold ore and it hosted the then world's largest commercial scale bacterial oxidation plant which uses Gencor's BIOX« technology. Gold is recovered by gravity and flotation, with the regrinding of the sulfide concentrate before bio-oxidation to liberate locked gold in sulfi de minerals. The BIOX« product is leached using the carbon in leach (CIL) process. Gravity gold recovery is a major component of STP operations and its contribution to overall plant recovery is about ten to 13 per cent. Gravity recovery has undergone series of technological upgrading, since the very first circuit which consisted of a Knelson concentrator and a Gemeni shaking table which was incorporated into the milling circuit at the start of the plant. Presently, each of the gravity circuits which consists of Knelson concentrator(s), cyclones and Gekko InLine Reactors (ILR), are located at the Milling and BIOX« circuits. More recently a new gravity recovery facility comprising of four 48 inch Knelson concentrators and cluster of ten inch cyclones have been incorporated at the tail of the flotation circuit. An additional ILR will be commissioned in 2010 to treat the concentrate generated from the new Semi Autogenous Mill #2 (SAG 2) Knelson: concentrator tower under construction. Since the inception of STP, significant gravity recoverable gold has been recovered via Knelson concentrators and the employed circuits have seen a number of modifications and upgrades, motivated by ore mineralogical changes and recovery concerns. The pioneering adoption of the ILR technology in 2001 and 2003 was a critical factor in enhancing the improved recovery benefit of the gravity circuits. Therefore the objective of this paper is to highlight the mine's experience in the gravity recoverable gold process with emphasis on plant modifications and gravity equipment upgrade. Operational challenges and the contribution of gravity gold to overall plant recovery are also discussed.

Aug 1, 2010

By R D. Morri, D J. Alexander

The design and optimisation of mineral flotation circuits is currently performed using a combination of laboratory, pilot plant and full scale testing. Owing to the variable nature of flotation circuits and the complex nature of the flotation process, it is difficult to interpret the data collected from flotation testwork. JKSimFloat is a computer modelling package which is being developed to interpret flotation testwork data collected at the various stages of the mining cycle. The parameters derived from the program can be used to assess potential circuit configurations in both the design of new flotation circuits and in the refinement of existing operations. The aim of this paper is to outline the modelling methodology used in JKSimFloat and to outline how it can be used effectively to model data collected from either the laboratory, the pilot plant or the existing flotation circuit. The use of flotation model parameters in circuit evaluation will be demonstrated via the use of a case study based on data collected from ComincoÆs Red Dog lead flotation circuit.

Jan 1, 1998

By C Mann, S Swapp

"The mining industry is often challenged with the task of evaluating narrow vein open pit deposits. A realistic mineable solution from optimisation needs to accurately represent mining dilution and the practical limitations of mining equipment. Open pit dilution is driven according to mining method and fleet selection as this dictates the ‘selective mining unit’ (SMU) that can be practicably mined.Common evaluation methods represent dilution by:a mathematical dilution assumption addition of a dilution skin reblocking of the model to an appropriate SMU.This paper will explore an alternative method of applying dilution by adapting an underground stope modelling tool. By considering an SMU as a stope, automatic stope shape creators such as Datamine’s Mineable Shape Optimiser (MSO) can be used to create wireframes for each mining unit over the entire deposit. Using these wireframes, the model can be subblocked and assigned as either ore (inside the wireframe) or waste (outside the wireframe) prior to optimisation.The MSO process considers SMU geometry and a depth specific value-based cut-off. The result is an optimised solution for the deposit based on practical and achievable mining constraints rather than one based on generalised modifying factors.To evaluate the economic impact of the methods above, results have been costed and scheduled and a comparison of operating cash flows made.Citation:Swapp, S and Mann, C, 2016. Optimisation Improvements for Narrow Vein Open Pit Deposits Using Mineable Shape Optimiser, in Proceedings Ninth AusIMM Open Pit Operators' Conference 2016, pp 50–59 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 15, 2016

By Short KC

The Hunter Region, with a major part of the coal resources of New South Wales and a long history of coal mining, has experienced a rapid expansion of coal resource development in recent years. While there are inevitable conflicts between mining, urban development and related infrastructure, and between mining and other resources, the application of sound planning practices, and improved co-operation and co-ordination among the various parties, helps to reduce such conflicts. The planning process involves consideration of factors such as transport- ation (including port facilities), mine subsidence, provision for surface facilities, a,iC the need for buffer 'ones. In addition, provision must be made for urban expansion, often co-existing or in close proximity to present or future coal mining development. Approval of coal mining developments takes place within the legislative framework of the Environmental Planning and Assessment Act, 1979 (EPA Act), the Coal Mining Act, 1973 (CM Act) and the Mining Act, 1973. Considerable effort has gone into stream- lining and co-ordinating the procedures under these Acts. The EPA Act provides for regional and local environmental plans, as well as a linked process of development control and environmental impact assessment. The CM Act provides for the grant of exploration and coal mining titles and mechanisms for the responsible management of Mining.

Jan 1, 1987

By S Ferguson, G Noble

The mining industry is facing economic pressures to treat more challenging and lower grade ore types, as well as pressure relating to environmental impact and social license to operate. Preconcentration through bulk ore sorting has the potential to benefit all these areas by enabling mining operations to divert material of low economic value prior to processing, thereby achieving higher feed grades and recovery, while reducing the processing plant and tailings dam footprint and capital required throughout the life of mine. The effectiveness of bulk ore sorting depends on the heterogeneity of material at the measurement location, as well as the accuracy and precision of the measurement. An understanding of ore heterogeneity can be assessed using drill core data, which provides metre by metre elemental assays. This paper reviews such data and assesses the grade distributions over different scales, which suggests that sufficient heterogeneity exists at mining scales to allow the potential for bulk ore sorting. Prompt Gamma Neutron Activation Analysis (PGNAA) technology has proven to be a successful measurement technique within many industries, including mining. PGNAA was first developed in the early 1980’s for the measurement of the elemental composition of bulk materials on a conveyor belt. Today, Pulsed Fast Thermal Neutron Activation (PFTNA) technology is also applied in elemental analysis of bulk materials and has some advantages for bulk ore sorting. In order to enable effective bulk ore sorting, however, a PGNAA/PFTNA analyser must be designed to provide a representative bulk ore analysis with the necessary accuracy and precision. Examples are presented to provide an understanding of the factors affecting PGNAA/PFTNA performance in relation to effective bulk ore sorting.

Nov 10, 2020

The mining industry, both here and internationally, is continually developing increasingly sophisticated software to compute mineral resource estimates, but these processes cannot compensate for a flawed geological interpretation of the geology of the economic commodity(s) concentrations. Quality assurance and quality control (QA/QC) is becoming increasingly common in association with the sampling and assaying practices within the industry. However, it is rare in the case of a geological interpretation associated with mineral resource estimation. Why? In the context of this paper, QA/QC relates to the use of statistical and graphical tools to show that the geological economic commodity concentrations have been appropriately domained. Domaining is essential to improve the chance of getting a mineral resource estimate right. Commodity value and acceptable concentration variation within a mineral resource can be ingredients that make mineral resource estimation difficult to get right. But it is possible to get it right a very high proportion of the time. It is more likely to occur when inappropriate data consolidation is minimised. In any case, inappropriate data consolidation is significantly reduced when the geological interpretation is strongly consistent with the data and it is demonstrable. To achieve quality global estimates of geological domain concentrations, it is essential that the geology of the prospect is understood sufficiently that the deposit is appropriately domained. Appropriate domaining occurs when sample populations are separated in such a way that only data in harmony with each other within the population contributes to the domainÆs concentration estimate. The paper will use four brief case studies to illustrate how QA/QC can be used to display data and validate the underpinning geological interpretation through its associated domaining to get it right when it comes to a mineral resource estimation.

Jan 1, 2007

Gas dynamic phenomena, particularly instantaneous outbursts of coal and gas are problems experienced in gassy, highly stressed coal, both usually the result of depth. Diff- erent mining geometries present different opportunities for seam gas to escape, starting from the virgin condition unaffected by mining and ending with the mining of the coal. The mining of the coal varies from entering a virgin seam cross-measure, heading out into virgin seam, advancing longwall faces into virgin seam and extracting developed blocks from large longwall retreating blocks to small pillars. Each method has its particular gass- iness patterns and particular stress patterns, both changing to some extent with time, and changing as mining progresses. Geological structural anomalies are the cause of gas and stress anomalies, causing in turn greater gas and stress manifestations. Pre-drainage of gas from the working seam not only degasifies the coal but causes it to shrink and so may affect stress as well as gas patterns. Unfortunately prior degasification is not all benefit, and there are some d13- advantages to its use. Also although it is possible to degasify places ahead, gassiness will return if drainage holes are shut down or sealed up and other deleterious aspects may be induced. Research should continue into the problem of instantaneous outbursts of coal and Gas.

Jan 1, 1986

By A Giyose, V Malysiak, K Davey

Batch flotation tests were conducted on a haematite-bearing Sishen iron ore slimes sample from South Africa using reverse cationic flotation. The effect of grinding on flotation performance, the flotation response of various key impurities in the sample, and the feasibility of increasing metal recovery by refloating tailings in a scavenger flotation step were investigated. The test results indicate that reverse cationic flotation is effective in rejecting impurities from the iron ore sample tested. From a head grade assaying 6.4 per cent SiO2, 2.14 per cent Al2O3, 0.402 per cent K2O, 0.082 per cent P and 0.194 per cent TiO2, the levels of impurities were reduced to 1.83 per cent SiO2, 0.88 per cent Al2O3, 0.095 per cent K2O, 0.066 per cent P and 0.174 per cent TiO2 in the final concentrate at a Fe recovery of 74 per cent. The flotation response of SiO2, Al2O3 and K2O were found to be better than that of P and TiO2. The testwork demonstrated that grinding to 80 per cent passing about 49 microns is essential for upgrading the Sishen iron ore to produce >67 per cent Fe concentrate grade. This grind size corresponds to about 80 per cent liberation of haematite from the gangue minerals. Fe recoveries up to 76 per cent were obtained by refloating the rougher tailings in a scavenger stage, with little effect on the final concentrate grade. Size-by-size Fe recovery data obtained indicated that particles below ten microns were mostly lost in the desliming stage conducted prior to flotation whilst some reported to the froth by entrainment. Some of the coarser haematite-gangue composite particles reported to the froth product by genuine flotation.

Jan 1, 2009