Search Documents

By C Wu, H Chen

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.The Halasu porphyry copper belt, located in the East Junggar basin bounded by Chinese Altay to the north and the Tianshan mountains to the south in the Central Asian Orogenic Belt, is one of the major porphyry copper belts in Xinjiang province, north-west China. Combined with previous studies in this area, the magmatism can be divided into three periods: pre-mineralisation activity of 390 Ma syn-mineralisation activity of 380–370 Ma post-mineralisation activity of 360–330 Ma.Through the comparison of zircon chemistry from ore-bearing and barren syn-mineralisation intrusions, negative correlation was identified between Ti-in-zircon temperatures and oxygen fugacity, corresponding to the fact that late-stage syn-mineralisation granitoids contain high water content, high oxygen fugacity and low temperatures with higher mineralisation potential. In addition, the relative low initial 87Sr/86Sr ratios, high eHf(t) and eNd(t) values and mantle Pb isotope characteristics in this study support that the magma forming these intrusions was probably derived from juvenile crust generated during subduction-accretionary processes.CITATION:Wu, C and Chen, H, 2015. Zircon trace elements and Sr-Nd-Pb-Hf isotope systematic of the Halasu porphyry Cu belt, north-east Xinjiang, China, in Proceedings PACRIM 2015 Congress, pp 637–640 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By H Austrheim, A K. Engvik, A Putnis

How aqueous fluids move through rocks and minerals is a question of possible pathways and mechanisms. Existing pathways such as fractures and grain or mineral boundaries provide obvious channels for fluid movement. We show how minerals reactive in the presence of an interfacial fluid can be replaced by new product phases through a process of interface-coupled dissolution-reprecipitation. A resulting porosity in the new phase provides a new pathway for fluid movement and therefore mass transport through the mineral, which progressively reacts at a moving interface. Eventually fluids of new and changing composition can pass through originally solid minerals and move on further, taking remobilised elements with them, to be reprecipitated whenever the chemical and/or physical conditions allow. One such example is albitisation of rocks associated with mineralisation.

Jan 1, 2008

In the last several years we have seen the demise of the Department of Mining and Metallurgy at the University of Melbourne, the removal of extraction metallurgy from the Department of Metallurgy and incorporation of it within a School of Mines at the University of New South Wales, and the joining of a small Department of Metallurgy with a Department of Chemical Engineering to form a Department of Chemical and Materials Engineering at the University of Newcastle. Most of these changes have been forced by the logical application of the principles of accounting, the currency for such accounting being the Whole Student Unit (WSU). It is not my intent to address the problem of attracting young people into courses in metallurgy (including extraction metallurgy) which, at present, is the only way to introduce black ink into the WSU accounting ledger. Rather, I wish to express my disquiet over the trends, illustrated by some of the above occurrences, of separating out extractive metallurgy from METALLURGY by suggesting in broad terms how a course in metallurgy should be structured. I firmly believe that the mechanical metallurgist and materials engineer need an exposure to chemical and extractive metallurgy; similarly, the extractive and process metallurgist should, in my view, have a good grounding in the interrelationships between composition, structure, and properties, this topic being the core of the basic subject physical metallurgy.

Jan 1, 1987

By S Jeon, K Haga, A Shibayama, L Godirilwe, C B. Tabelin, I Park, A Buronov

Open pit/underground mining and mineral processing can generate large amounts of waste that contains sulfide-type minerals such as pyrite (FeS2), and it can produce acid mine drainage (AMD) when exposed to oxygen and water. This highly acidic wastewater contains heavy metals and this is one of the most serious environmental issues after mining operations taking several decades to completely remediate with high costs. For green mining, the present study focused on the development of a recovery technique for gold from an eco-friendly solvent, thiosulfate, by utilising mine wastes, tailings. First, gold recovery experiments in ammonium thiosulfate system were carried out using model samples representatively present in tailings (ie SiO2, Al2O3, FeS2, Fe2O3, and Fe3O4). The results showed that gold recoveries were negligible when using Al2O3, SiO2, Fe2O3, and Fe3O4 while pyrite shows a recovery efficiency three-fold as high as the maximum recovery efficiency when using others. Subsequently, the study also addressed the identification of the recovery mechanisms and post-recover process. The results indicate that tailings can be sufficiently utilised for gold recovery in the hydrometallurgy process and a further sustainable process can be established.

Sep 1, 2024

After a short presentation of the Division of Mining at the Royal Insti- tute of Technology, Stockholm, Sweden, the author presents some of-the fill research carried out at the Division. Literature surveys and testing methods and equipment are described. The use of flocculants' in hydraulic filling has been tested both in laboratory and in mines and the results are very promi- sing. Finally compressibility investi- gations and some finite element calcu- lations are presented.

Jan 1, 1973

By V A. Diemar

The Chatree Gold Project represents a greenfields discovery of metallurgically clean shallow gold mineralisation in a logistically simple terrain. Total Measured, Indicated and Inferred Resources are currently 31 tonnes of gold and 160 tonnes of silver. Gold occurs in an adularia-sericite epithermal system within quartz-calcite-adularia veins, breccias and stockworks. Host rocks are volcanic arc porphyritic latite-trachyte flows, their pyroclastic equivalents and volcaniclastics of upper Permian to upper Triassic age. The mineralisation was deposited in dilated zones during repeated reactivation of pre-existing structures. To-date five mineralised prospects have been defined by drilling with three reaching JORC Code Mineral Resources status. The project is in its definitive feasibility stage and is anticipated to be in construction during 2000.

Jan 1, 1999

By M Yahyaei, F Reyes, R Lage, V Jokovic

Equipment wear is strongly related to the performance of grinding circuits. In particular, SAG mills are subjected to the wear of their shell liners and grates. Changes in lifter height and face angle impact mill performance, while classification at the mill discharge is also affected as grates wear out. Moreover, liner mass loss caused by wear affects how operators interpret readings of sensors such as load cells or bearings pressure. Automating and optimising grinding circuits under these constrain becomes challenging due to the nonlinear and dynamic nature of the system. The operation of SAG mill grinding circuits remains largely dependent on human intervention, which frequently results in inconsistencies in performance across shifts, reflecting the operator’s personal preferences, experience, and other human factors. The influence of human factors can be reduced by careful training of operators as well as by automation using advanced supervisory control. The latter approaches could benefit from the development of dynamic process models that consider the effects of wear on the performance of equipment over time. This paper presents detailed industrial data showing the effects of wear on SAG mill performance. Additionally, a dynamic SAG mill model that accounts for these phenomena is proposed and demonstrated in a simulated environment. This model is shown to mimic the effect of wear on the performance of industrial scale mills and the operational constraints they are subject to, thus extending traditional SAG mill models. Incorporating wear into modelling and simulation platforms can improve the understanding of the effects that wear can have on the performance of key assets in comminution circuits and may allow the development of more robust model-based advanced process control strategies.

Aug 24, 2022

By G Reynolds, L Lu

Queensland Pacific Metals (QPM) is developing its flagship Townsville Energy Chemicals Hub (TECH) facility to produce nickel and cobalt sulfates from imported high-grade nickel laterite ore for nickel-cobalt-aluminium and nickel-cobalt-manganese Li-ion batteries. The TECH facility is expected to use a patented leaching, recovery and recycling process called the DNi Process™. It uses the nitric acid leaching process for extracting nickel, cobalt and other valuable metals from laterite ore. Apart from the nickel and cobalt sulfates, the TECH Project will also produce high purity alumina, hematite (~640 ktpa) and other by-products. The hematite by-product precipitated from the DNi Process™ (hematite precipitate hereafter), is high in Fe and particularly low in impurities. QPM is working to identify potential applications for these high-purity by-products to generate additional revenue and to achieve its zero-waste ambition. As such, QPM has engaged CSIRO to evaluate various agglomeration options to produce low-cost, hematitic products suitable as ironmaking feed materials. This paper will first reveal the unique characteristics of the hematite precipitate arising from the TECH Project and then examine the sintering and pelletising processes for preparing the hematite precipitate as an ironmaking feed.

Sep 18, 2023

By Hannan JC

Consent to develop and operate a new coal mine in New South Wales (NSW) will be conditional upon a number of environmental controls. In NSW, applications for any new major development associated with coal mining are determined by the Minister for Planning and Environment. The environ- mental conditions placed on the development consent, the coal mining lease and the approvals, and licences under the pollution control legislation amount to a substantial component of any new project's commissioning considerations. The nature, scale and location of projects and the principles of pollution control on which conditions of State Pollution Control Commission (SPCC) approvals are based have a considerable influence on project planning. The design, construction and operation of coal mines in NSW has been progressively modified over the past 15 years, to incorporate increasingly stringent requirements for environmental management. These requirements are in turn, a reflection of a greater community demand for environmental protection.

Jan 1, 1986

By P M. Dight

Shotcrete usage in declines and developments has become pervasive as operators strive to achieve production improvements. Issues of mix control, fibreload, thickness control, temperature and curing conditions all play a part in the quality control. Often to overcome some of the quality control issues designers over specify the strength requirements in order to meet their operational constraints. Adherence to the standard civil testing requirements of 28 days moist cured at 21ºC without properly calibrating these results to the changing environment underground leads to contractual disputes. There are a number of standard tests specified including cylinder tests, cored tests, beam tests and round determinate panel (RDP) panel tests. The logistics of storing these samples and then transporting them to concrete testing laboratories without due regard to temperature changes with time can influence the results. All the samples can be readily handled by personnel except the RDP panel. The standard RDP panel is 800 mm diameter by 75 mm thick and requires an ITH machine at the mine and a fork lift at the laboratory to move it around. This paper will examine the possibility of a panel which provides scalable results to the standard RDP panel but can be easily handled by personnel and/or tested on site with suitable equipment. This allows for faster turn around and better quality control for the sample prior to testing. This enhances the identification of quality control issues at the mine and improves safety.

Mar 21, 2011

'Industrial Minerals - their mining and use in New Zealand' is the theme of the 1978 Annual Conference of the New Zealand Branch of The Australasian Institute of Mining and Metallurgy. This paper describes the use of phosphate rock, sulphur and potassium chloride (potash) - three industrial minerals which have enabled the farmers of New Zealand to increase production to current levels. The growth of imports of these raw materials for the New Zealand fertiliser industry is well documented in NZ Fertiliser Statistics 1977. This is the most recent of the Ministry of Agriculture and Fisheries annual publications on this Subject prepared from the detailed returns of fertiliser manufacture and sales from each fertiliser works. There are now 12 of these works in New Zealand one of the most recently established being in Whangarie where this conference is being held. Its capacity to manufacture superphosphate will shortly be 300 000 tonnes twice that when it opened late in 1964. New grinding and manufacturing equipment comes on stream early in 1979. This paper illustrates the interdependence of two primary industries, agriculture and mining. New Zealand's economy in the foreseeable future will be based on agriculture so that our standard of living is dependent on the overseas prices and freight costs of the bulk raw materials from which our fertilisers are made. For the year ended 31 March 1978 New Zealand's total exports were $3395 million, of this total $2413 million (71%) came from the products of pastoral agriculture (wheat, wool, dairy and other animal products), $291 million from forest products and $501 (15%) from manufactured exports. Approximately half of the pastoral receipts can be attributed to the fertilisers applied at a total cost of about $200 million including subsidy.

Jan 1, 1978

By M Olsson, I Bergqvist

A Swedish table of blast damage depths has, in one form or other, been in use since the late-1970s. Its history and the underlying theory are described. New experimental and theoretical findings that point out a number of shortcomings in the table and the underlying theory are presented and discussed. A revised version of the blast damage table was recently introduced in conjunction with new but incomplete recommendations for cautious perimeter blasting. The new table leaves the difficult task of taking into account factors like decoupling, water in the borehole, the rock properties, type of initiation, charge length and the actual bit diameter to the user. This paper discusses different ways of doing this, based on the experimental findings and a recent formula for the prediction of the lengths of radial cracks behind the half-casts. The material presented in this paper is meant to supplement and extend the new Swedish recommendations for cautious perimeter blasting of tunnels, shafts, pits and road cuts.

Jan 1, 2001

The theme at this yearÆs AusIMM New Leaders Conference in Ballarat was æThe Minerals Industry û Future Directions for New LeadersÆ. There was a strong focus on the recruitment and retention of trained and skilled graduates and new professionals into the mining profession. This paper highlights some of the key findings and discussion points from the New Leaders Conference. While some of the main causes of the decline in attracting new geoscientists to the mining industry have been identified, there still remains a lack of accountability among a number of Australian mining companies. Some of the factors identified that are driving new graduates away from the industry include; the social and geographical isolation, the long hours in challenging conditions and a difficulty in obtaining work straight out of University. Often there appears to be no clear opportunities within companies for career development and advancement. The opinion also still persists that the mining industry is lagging behind in both environmental and technical developments, which makes entry to the industry unattractive. Solutions that some of the large players in the Australian mining industry are implementing to help reverse the trend include targeted marketing of the lifestyle, money, freedom and travel offered in the mining industry, the development of graduate recruitment programmes and much more emphasis on the quality and reputation of the companies themselves. Incentives to attract families have also been significant in attracting and retaining employees whom otherwise would have left the workforce. However, more still needs to be done to completely reverse this trend and the mining industry needs to continue to be proactive in marketing itself as a desirable employer and career choice option for students and new professionals.

Jan 1, 2004

By S van der Sluijs, M van Ende, Y Tang, A Emami

This paper presents a phenomena-based model for investigating the possibility of scrap melting in an Open Slag Bath Furnace (OSBF) for green ironmaking. The goal of this study is to enhance the circularity of the steelmaking process by utilising scrap as a green source of iron in OSBFs. The model takes into account the fundamental differences between OSBFs and traditional processes such as Electric Arc Furnaces (EAFs) and Basic Oxygen Furnaces (BOFs). The model considers three primary regions where scrap heating and melting occur: the solid feed pile, slag and hot metal. It accounts for factors such as the furnace geometry, scrap charging mechanism and specific heat and mass transfer properties of the reactor. The model was validated using literature data and was used to investigate the heating and melting behaviour of individual scrap particles under various process parameters. The study finds that the scrap melting process in OSBFs involves three stages: shell formation, shell remelting and subsequent melting of the parent scrap. The carbon content of the scrap and the liquid hot metal plays a critical role in determining the melting behaviour. Depending on the carbon concentration and temperature, the melting process can be heat transfer controlled or mass transfer controlled. The paper also examines the scrap feeding methods in OSBFs, including direct charging into the slag or charging through a feed pile. The model provides insights into the melting rate of scrap compared to Direct Reduced Iron (DRI) in OSBFs and highlights the role of carbon in this process. Overall, this phenomena-based model contributes to the understanding of scrap melting behaviour in OSBFs and provides valuable insights for optimising the circularity and efficiency of green ironmaking processes. The findings of this study can inform the design and operation of OSBFs, paving the way for increased utilisation of scrap as a sustainable feedstock in the steel industry.

Jun 19, 2024

This paper describes modern long-term mine scheduling and gives an example of its application. It then discusses the obstacles to the implementation of such schedules.

Sep 26, 2011

By J Rola

This paper outlines a laboratory-based design method, founded in critical state soil mechanics, for identification of an appropriate compaction specification to ensure dilative conditions prevail across the design TSF stress range. The method makes use of the critical state line (CSL) and consolidation tests prepared at varying compactive efforts. The CSL and consolidation curves are plotted together in e-log p’ space, with the compaction curves transformed from vertical effective stress to mean effective stress using the coefficient of earth pressure at rest (K0). Consideration is given to the sensitivity of K0 as it is generally not available during the design phase. An example of the design method is illustrated with laboratory data.

Jul 1, 2021

By Salmon P. T, Gilmour R

Commercial production of zinc started at the Pasminco Metals - EZ Plant, Hobart, Tasmania, in 1921. Since that time the capacity of the plant has been steadily increased to its present level of almost 220 000 tpa. Major areas of the plant have been successively upgraded over a number of years, (Roasters, 1969, 1975; Acid Plants, 1981; Casting, 1972; Residue Treatment Plant, 1971), but, until recently, the leach/purification area remained virtually unchanged from the time the plant was built. The major redevelopment of the hydrometallurgical plant began with fully integrated pilot plant testing of the proposed new circuit in 1981. The pilot plant incorporated the Low-contaminant Jarosite Process, and a new two-stage zinc dust purification procedure. In 1985, approval was granted for a major modemisation program which involved the complete replacement of most of the leaching and purification plants, and substantial improvements to the residue treatment plant. Construction of the first of the new plant sections, Strong Acid Leaching, commenced in 1986. This paper describes briefly the modernisation program itself, and the current method of zinc production at the PMEZ plant. The new plant sections comprise a Strong Acid Leach stage to improve lead residue grade; a Preneutralisation stage to reduce metal losses in jarosite; new filtration stages for both jarosite and lead residue; new Neutral Leach and Weak Acid Leach stages to replace old equipment; a new Solution Purification stage to replace the use of organic reagents to remove cobalt; and a new Gypsum Removal stage to cool the solution before electrolysis. At the completion of the modernisation program, only the electrolytic cellhouse remains of the early plant sections.

Jan 1, 1993

By R O. Laidlaw, J L. Mauk

The Coeur d'Alene mining district in northern Idaho, USA is the second largest producer of silver in the world. Mesothermal silver-lead-zinc veins occur in the metasedimentary rocks of the Belt Supergroup with five main types of associated hydrothermal alteration: 1) feldspar destruction, 2) hydrothermal bleaching, 3) carbonatisation, 4) sulfidation, and 5) silicification. Hydrothermal bleaching is characterised by hematite destruction with associated siderite and quartz veins and veinlets, coarse euhedral pyrite and magnetite. Bleached zones envelop both mineralised and barren veins and extend for metres to tens of metres into the wall rocks. Carbonatisation consists of addition of siderite, which occurs as veins, veinlets, stockwork, irregular blebs or spots, and coarsely disseminated grains, depending on the relative distance from the main vein structure. Siderite envelops nearly all mineralised veins, relates to all other alteration types and extends from several metres to tens of metres into the wall rocks. Pyrite and galena alteration dominate sulfidation and are associated with some mineralised veins. Pyrite alteration strongly correlates with siderite alteration and exists in three main forms: a) very fine-grained pyrite flooding, which can extend for metres to tens of metres into wall rocks; b) coarse-grained, euhedral pyrite, which is sporadic and associated with the redox boundary in hydrothermally bleached zones; and c) small isolated zones (6 - 15 cm) of medium-grained, subhedral to euhedral pyrite associated with pervasive siderite alteration. Where present, disseminated galena extends for metres to tens of metres into the wall rocks. Silicification is characterised by veins, veinlets, stringers, irregular patches and variable hardness in siltites and commonly appears in association with hydrothermal bleaching and siderite alteration. Although related to mineralisation, silicification is sporadic and in most places a clear envelope around mineralised veins cannot be identified.

Jan 1, 2001

By R Urie

Dilution and loss of ore during the mining process invariably occur in all underground mining operations. This dilution and ore loss can have a significant effect on the performance and value generated from a mining operation. Further, excessive dilution or greater than anticipated ore loss during mining is often one of the key reasons for the underperformance of a mining project when compared to a feasibility study or annual budget. Mining professionals often go to great lengths preparing detailed mine plans, schedules and economic models only to then apply high-level estimates or rule of thumb values for dilution and mining recovery that can ultimately lead to inaccurate forecasts for the performance of a mine with the resultant loss of value due to the mining of uneconomic material or the loss of potentially valuable ore. This paper discusses processes and practices that can be practically used to manage dilution and mining recovery in an underground mining operation with a focus on understanding and then maximising value. The processes cover items such as the definition and measurement of dilution and mining recovery, techniques for the estimation of dilution and mining recovery, consideration of the economic implications, management of dilution and mining recovery through the stages of the planning cycle, and practices to reduce dilution and improve mining recovery. Common misconceptions and omissions are also discussed.

Mar 29, 2023

By M E. Webb

Safety is a key value in most leading mining companies. Despite years of effort, and significant expense in ‘programs’, operating sites seem to have been left with no real improvement in either the elimination of fatalities or sustained reduction in injuries.Safety systems and processes have grown and evolved, often to the point where they have become overly complicated and marginally useful.MMG Limited, following the consolidation of its Australian operations under a single management structure, undertook a program to effect real and sustained change in its approach to managing safety. The program aimed at improving safety by better engaging its workforce and by making safety processes simple, useful and effective. It defined the role of the supervisor in creating safe work, the role of the people doing work and the role of safe work methods.A safety diagnostic tool was developed to assess site against safety-critical mindsets, behaviours, cultures and systems. The outcome of the diagnostic is considered by the organisation to be the true lead indicator of safety performance.While still a work-in-progress, the program at the Australian Operations of MMG Limited shows that challenging common paradigms in safety management can create real change in safety performance.CITATION:Webb, M E, 2016. Making safety simple, useful and effective, in Proceedings International Mine Management Conference, pp 217-223 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 22, 2016