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Plenary Address Zinc is a trace element in all igneous rocks and its background geological occurrence roughly follows iron but at much lower concentration. Living matter reflects this abundance and zinc is an essential trace element for complex life forms. Thus, environmental issues include zinc deficiency in soils and/or water - and thus in local diets - and zinc toxicity evident in natural or modified ecosystems. Increased knowledge of the role of zinc in plant and animal metabolism emphasises the need to manage, within guidelines based on naturally occurring abundances, the concentrations of zinc in water, spils and in the food chain. Although recognition of the natural variability of zinc concentration provides some basis against which environmental protection standards might be set, the measure of environmental `pollution' is more commonly taken as the degree of change to natural, background levels, attributed to the particular land or water use activity. Environmental constraints on mining, processing and usages of zinc may have less to do with actual

Jan 1, 1993

Zinc concentrates from the newer mines and from proposed developments provide both opportunities and processing challenges to the conventional roast-leach electrowin smelters. These concentrates are often characterised by low iron, elevated silica, possibly high manganese, and levels of elements such as germanium which may cause concern. In addition, environmental constraints on residue disposal are forcing significant changes to some smelter practices. Iron in concentrate, and the resulting environmental impact of residue disposal are now major questions. However, normal concentrate tariff structure provides a disincentive against smelters taking high grade concentrate and oxide fume. Processing technology to cope with these changes is reviewed, as is de-watering and materials handling of ultra-fine concentrate. Within a few years, such fine concentrates will account for up to 1 000 000 t/y of contained zinc. New processing technologies including novel transport methods, siliceous leach circuits, manganese removal cells and front-end smelting will become significant in zinc smelting.

Jan 1, 1993

Australia has been an important producer of zinc minerals and metal for many years.Late in the last century Edgar A. Ashcroft, a versatile and enterprising electrical engineer proposed the treatment of zinc rich ores by roasting, followed by leaching to extract zinc, purification of the solution and electrolysis of the purified solution to produce zinc. Residues from the leaching operation were to be smelted in a lead blast furnace to recover lead, silver and gold.Ashcroft (1897-98) and (1898) has.given us a most interesting record of the attempts made at the Sulphide Corporation's plant at Cockle Creek near Newcastle, NSW, to put his ideas into practice. In spite of the best efforts of all concerned, including the use of electrolysis of aqueous chlorides and sulphates, zinc could not be deposited consistently and the project failed although lead smelting continued until 1922 (Woodward, 1965, p. 158). Based on later experience with Broken Hill materials the presence of undetected cobalt in the solutions was the likely cause of the inability to deposit zinc (Kirk and Othmer, 1956).

Jan 1, 1985

The history of zinc production in Australia is outlined including attempts to make zinc electrolytically at Cockle Creek, N.S.W. in the last century, the use of horizontal retorts at Cockle Creek and Port Pirie, South Australia, production by electrolysis at Risdon, Tasmania and at Port Pirie using zinc oxide fumed from lead blast furnace slag and production by the Imperial Smelting process at Cockle Creek. Developments in the electrolytic process are described including those in roasting, acid manufacture, leaching, purification, electrolysis, melting and casting. The Imperial Smelting process technology is also outlined. In both processes global technology is reviewed, including important Australian contributions.

Jan 1, 1986

From 1980 to February 1991 the Rosebery concentrator purchased ore from Aberfoyle's Que River Mine. Following the termination of the contract the concentrator reverted to treating Rosebery ore alone. Since that time it has become apparent that the circuit configuration employed was no longer optimum for zinc metallurgy. The circuit was designed to treat a difficult, slow floating sphalerite; however, the opposite was now found to be true. The sphalerite is fast floating and the circuit was cumbersome. During 1992 extensive circuit changes led to the provision of a simple open circuit flow sheet. The circuit is now easier for operators to understand and lends itself to improvements in process control. Middlings streams have been minimised, which produces a far more stable circuit. Significantly, it must be noted that the key to achieving potential results must lie in reducing variations within the process. A significant ore characterisation program has been undertaken, providing an insight into the metallurgical compatability of the ore to be mined. Using the information collected in this program, metallurgical recoveries and grades can now be predicted with a geater accuracy. Ore characterisation data suggests that an improvement from a 54 per cent zinc concentrate to a 57 per cent zinc concentrate should be achievable. By understanding the size-by-size mineral assemblage, a strategy for concentrate grade improvement has been developed. The requirements of the customer must in all cases determine the quality of the product. Pasminco is a fully-integrated zinc producer and as such significant gains can result by tailoring the concentrates to suit the Smelters.

Jan 1, 1993

Published information on technical and market developments in the uses of zinc tends to dwell very largely on two groups of uses of zinc - zinc coatings (mainly galvanising) and zinc casting alloys. These two groups account for two-thirds of primary zinc consumption. However, if total zinc consumption is taken into consideration, coatings and casting account for a little over half the total. Either way, the health - or otherwise - of these 'other' uses of zinc can have a substantial effect on the industry as a whole. The aim of this paper is to put the whole market picture for zinc into better focus, concentrating on the factors which can affect consumption in the 'other half' of zinc's markets: ò brass - the third most important market for zinc at around one million tonnes - responds to changes in the economic cycle. It has seen substantial changes in the balance between different forms of semi products, and, in Europe at least, some real market gains; ò zinc sheet - one of the original uses of zinc in Europe - has grown substantially in some countries, but remains almost unknown elsewhere; and ò zinc pigments and compounds are so numerous that - barring the substitution of zinc oxide in rubber - major overall changes in the market are unlikely. The paper examines these markets and assesses their potential and implications for zinc markets as a whole.

Jan 1, 1993

Cominco Ltd's Polaris Mine in Canada's High Arctic has been successfully mining zinc ore in permafrost since 1981. Mining methods using frozen backfill have been the key to success. The mine is now producing about 60 per cent of the ore from pillars while maintaining high productivities. Annual ore production is just over one million tonnes providing more than 200 000 tonnes of zinc concentrate each year. Cominco Ltd has adapted management and operating practices to suit the harsh environment and the isolated site, and has shown that a profitable development can be carried out in the tough Arctic conditions, with minimum impact on the environment.

Jan 1, 1993

By A Kyllo a, D R. Swinbourne

Electric arc furnace (EAF) dusts contain significant quantities of zinc, found almost entirely as either zinc oxide or zinc ferrite. The dust has been classified as a hazardous waste due to the relative high lead, cadmium and hexavalent chromium contents. It is important that environmentally acceptable processes be developed to treat this waste. One possible process involves reacting the zinc compounds in the dust with metallic iron, thus avoiding zinc vapour reoxidation by CO2 as occurs in carbon reduction processes. It consists of two stages where the first is the reduction of iron oxides to iron and the second the reduction of zinc oxide to zinc vapour by the iron. In this work the effects of operating variables such as temperature, CO/CO2 ratio and pressure on the recovery of zinc from an industrial EAF dust obtained from the Smorgon Steel Mill were investigated. Zinc recoveries in the second stage were found to approach 100 per cent at 1000oC after about four hours in nitrogen but within 40 minutes if a low vacuum was used.

Jan 1, 2000

By Gemmell J. B

Zinc-bearing massive sulphide deposits have been mined in Tasmania since 1900. The current major producers are Hellyer and Rosebery, with total resource tonnages (mined plus reserves) of 16 Mt (million tonnes) and 24.8 Mt respectively. These deposits belong to the class of seafloor volcanic-hosted massive sulphides (VHMS) and are located within the Mt Read Volcanics, a narrow belt of continental margin calcalkaline volcanics of Cambrian age. Compared to other Australian VHMS deposits, and world-wide MVT and Sedex deposits, the Tasmanian examples clearly stand-out due to their high metal grades, averaging over 17 per cent Pb+Zn. The deposits vary in morphology from mound style (Hellyer) to sheet style (Rosebery) with other combinations including stacked lenses (Que River) and disrupted cross-cutting bodies (Hercules). All deposits show the classic VHMS zonation from an Fe-Cu-bearing base to a Zn-Pb-Ba-rich top. Zinc, gold and silver tenor commonly increases toward the stratigraphic top of the deposits. The ores have been deformed during regional metamorphism, resulting in folding, shearing and recrystallisation of sulphide lenses. In addition to the major deposits, a number of small massive sulphide prospects occur throughout the volcanic belt and the potential for the discovery of further large, deeply buried deposits remains high.

Jan 1, 1993

By Houchin MR, Jenkins DH

This paper examines the importance of processing to the properties and performance of high purity zirconia ceramics. Many of the principles discussed, however, apply to ceramic processing in general. For fabricated ceramic articles to display their wide range of high performance properties, they must be made fully dense. The precursor powder and postpowder processing requirements necessary to achieve full density in the fabricated body are discussed. Brittleness, the anathema of ceramics, can be overcome in zirconia by incorporation of toughening mechanisms. Transformation toughening and microcrack toughening and their origins in partially stabilized zirconia are reviewed.

Jan 1, 1989

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 L D. Meinert

Skarns typically are zoned and the deposit- or district-scale zonation pattern is an important tool in exploration for skarn deposits. Zonation in individual deposits has been described in many publications, and the general zoning patterns have been summarised by Einaudi, Meinert and Newberry (1981), Meinert (1997), and Meinert, Dipple and Nicolescu (2005). Although zonation is present in most skarns as the result of a basic process of transferring heat and fluids from magmas to wall rocks, the specific zoning pattern in each skarn may vary greatly. For example some zones may be missing entirely or multiple zones may be telescoped. Such variations can be caused by several factors including depth of formation, magma composition, timing of the exsolution of magmatic aqueous fluids, redox state of the magma and redox state of the wall rocks. To use zonation as a predictive tool in skarn exploration, all the controlling factors have to be considered. In this study, we discuss some of the factors that may affect the zoning patterns in Ca skarns. Magnesium skarn has dramatically different mineralogy and is not discussed here. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By Espi J

The Nena high sulphidation deposit, located in the Sandaun Province, PNG, contains a measured and indicated resource of 51 Mt of copper ore grading 0.5% Cu and 0.6 g/t Au at a 0.5% Cu cut-off. The copper orebody is overlain by an 18Mt oxide gold resource grading 0.1 % Cu and 1.4 g/t Au at a 0.6 g/t Au cut-off. The deposit is hosted in advanced argillic altered pyroclastics interstratified with lavas, volcanoclastics, epiclastics and sediments of the Debom Volcanics within the Frieda River Intrusive Complex. Foraminiferal sediments indicate the Debom Volcanics to be Early-Middle Miocene in age. Alteration is elongated along, and concentric about a northwest trending structure (Nena Structural Corridor) which is about 7km in length. The inner two alteration types, residual and massive silica-alunite are strongly brecciated and host the bulk of later hypogene Cu-Au mineralisation. Weakly mineralised weak silica- alunite and barren peripherally zoned clay alteration surround the inner mineralised alterations. The hypogene sulphide deposition was polyphasal, episodic and is zoned from north to south from covellite-enargite ¦ chalcocite (5600N to 5200N) to a mixed enargite-luzonite (5200N to 4700N) to luzonite-stibioluzonite (4700N to 4400N) in the south within a 1200m long by 300m diameter sub horizontal pipe like body. Paragenesis studies indicate that pyrite ¦ marcasite were introduced early with barite and black native sulphur before deposition of banded pyrite (melnicovite) with barite during a period of brecciation. Continued brecciation allowed bladed covellite ¦ chalcocite followed by enargite-luzonite-stibioluzonite ¦ pyrite (brassy) and minor acicular covellite deposition. Yellow native sulphur and trace amounts of galena were deposited in remaining pores. Pre-acid alteration intrusives domed the mainly volcanic stratigraphy in the southwest and post-mineralisation porphyries in the northeast truncate mineralisation. Supergene processes and erosion have modified the top of the deposit, creating a 45m thick goethitic-scoroditic-haematitic gold cap above a 40m thick (on average) chalcocite rich supergene blanket. Lesser amounts of digenite, covellite native copper and rarely seen malachite occur in the supergene copper zone.

Jan 1, 1997

By J L. Merritt

The mining industry seeks to engage with and respond to stakeholders through open consultation processes during the various phases of a mining project (Department of Industry, Tourism and Resources, 2006). Two Australian Coal Association Research Program (ACARP) funded projects conducted in the Bowen Basin coalfields in Central Queensland investigated the use of a stakeholder panel for the evaluation of mine site rehabilitation. The panel members were drawn from the local and regional area, and represented neighbouring landholders, traditional owners, AgForce, local government, conservation groups and non-governmental organisations (NGOs) such as Greening Australia and the Fitzroy Basin Association. The approach of utilising stakeholders to establish rehabilitation criteria was proposed as an alternative to the established practice of assessing rehabilitated areas against a suite of quantitative completion criteria; eg >70 per cent vegetative ground cover or <5 t/ha/a soil loss. The basis of this approach recognises the reality that the definition of completion criteria has proved problematic over the last 40 years with no broad consensus reached on the suite, let alone the metrics; eg the exact cover level that will benchmark acceptance of the mine site rehabilitation.CITATION:Merritt, J L, 2016. Zooming out – learning to see rehabilitation through stakeholders’ eyes, in Proceedings Life-of-Mine 2016 Conference, pp 163–165 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By Wooller R

The 3-D regular block model used for long term mine planning at Hamersley Iron did not fulfil the requirements for short term mine planning in terms of accurate representation of geological structures, contacts and boundaries in the orebodies. A computer model, based on zone plans, is being created as a single orebody model for all phases of mine planning. The zone plan is the primary interface between the geologists and mining engineers. It is essentially a bench plan at mid-bench height showing geological structure, material type boundaries, the grade and physical characteristics of ore blocks. The method allows for the dilution of ore zones by waste material. The stratiform nature of the orebodies allows zones of varying grade to be readily delineated on the plans. The Zone Plan Model (ZPM) is the interface between geological and mine planning computer systems. It is the basis of all mine planning with applications including long and short term mine plans, reconciliations, general ore reserve estimations, pit design and general model enquiries. The system was designed to be user driven. The user has complete control at all times as all computer generated data are fed back to the user who may then elect to override the computer. Various controls were built into the system to ensure model validity and integrity. The system has proved to be invaluable as a tool for users with little or no computing experience.

Jan 1, 1986

This short paper outlines the authorÆs views regarding the present ability of the resources industry to manage its mining assets. It represents a personal view û but one founded in fact-based observations of mining companies and of the mining industry in general. It contends that whilst a great deal has been learnt about the management of mines over the last 500 years since the seminal work of Agricola, observations suggest that best practice management is the exception rather than the rule across our industry. Although insights regarding the successful management of mines have become apparent, we still witness unnecessary errors in our industry that lead to the loss of shareholdersÆ funds. By highlighting some aspects of current best practice, particularly in the arena of operations improvement, it is hoped that this short paper contributes a small step along the next 500-year-long learning curve. At a time of key skill shortages in our industry as mineral producers attempt to ramp-up production to capture historically high commodity prices, achieving best practice operations management has seldom been more critical.

Jan 1, 2006

By A Hanna

Quarries around Auckland have reached or are reaching the ends of their lives, which raises issues about rehabilitation. Significant volumes of 'cleanfill' are generated by the City, particularly during phases of urban renewal and development. Emplacement of the fill in quarries removes the problem of fill disposal and provides an opportunity for restoration of the quarry site.There is a compatibility between quarrying and cleanfilling because at quarries:Truck routes are already established Neighbours are accustomed to the effects and appropriate buffer distances have been established Bringing fill into a site attracts aggregate sales and is very efficient. Fill originates from construction sites and ad-hoc excavations and therefore it is not surprising that sampling has shown the quality to be variable. Both Winstone and the Auckland Regional Council have surveyed undisturbed soils in the region to attempt to determine natural background levels of common contaminant substances. Comparison of these levels with delivered fill shows that a high proportion of delivered materials can be regarded as mildly contaminated. Therefore the term 'cleanfill' is, in the Auckland region at least, a misnomer and the term 'managed fill' has been adopted.Historically and presently the only control on quality of 'cleanfill' has been some visual inspection. This leaves the fill operator open to potential liability for creating a contaminated site. Implementation of controls at WinstoneÆs operations has progressed slowly, over some ten years. This is mainly due to the perception that mobility of contaminants within and out of the landfill will be very limited because of the near-neutral pH and abundance of clay minerals in the fill. The methods of control and results of environmental risk assessments at WinstoneÆs Puketutu Island Quarry will be briefly described.

Jan 1, 2002

By S M. Stewart

Industry, especially extractive industry, must now give serious attention to the impact its operations have on the natural environment and on the economic, social, and cultural context within which it operates.   While this obligation is statutorily managed, there has been a recent shift towards a culture of self responsibility. Industry is now talking about earning its ôsocial licence to operateö and the importance of maintaining the ôtriple bottom lineö, thus adding environmental and social performance to the usual financial criteria used to measure organisational performance. The social context within which companies operate has also become more sensitive with industry responding to a growing public expectation that it conduct itself in a way that strives for sustainability by operating and developing in a way that meets the needs of the present without compromising the ability of future generations to meet their own needs.   There are glowing accounts of industries engaging and collaborating with the communities within which they are based. In amongst these are also some disasters which result from cultural assumptions, industry created dependencies and the failure to attain community buy-in despite significant investment by the industry involved.   There are also remarkable stories of communities, and action groups within communities, being a significant catalyst for positive change of their natural, cultural and social environment. In amongst these stories there are also accounts of long and drawn out battles; adversarial situations where no one wins; a litany of mistrust, tricks and tactics, with the better resourced party ultimately achieving its primary objectives at the cost of the other (and at the cost of any potential fruitful, mutual relationships).   So what makes the difference in achieving the positive rather than negative outcomes? The answer lies in the way the outcomes are achieved. Building relationships based on good communication, respect for divergent views, mutual understanding, and the development of trust and empathy, makes it possible to identify shared goals and objectives that best meet the needs of all parties.   Research indicates the mining industry is making good progress in developing policy and commitment to community development and engagement but that, ætranslating commitments into improved practices at the site level remains one of the industryÆs toughest challengesÆ. (Australian Government - Community Engagement and Development Handbook October 2006 @ page 49.)   This paper considers the merits of a process of community collaboration and what it has to offer in terms of meeting that challenge.

Jan 1, 2007

By B, T Norgate, S Sanetsis, R Davidson

Global cement production accounts for about five per cent of man-made CO2 emissions (WBCSD, 2002). Such operating practices will increasingly be considered unsustainable, unless significant reductions in environmental impact can be realised by the industry.Slag is a high volume waste product from ironmaking, with about 300 kg of slag being produced per ton of iron. Critically, one ton of slag waste, if used as a replacement feedstock for Ordinary Portland cement (OPC), can prevent around one ton of emitted CO2 since no calcining is required. Slag cement blends can also show superior properties compared to OPC, such as lower heats of hydration and higher late strengths, but more development is needed to overcome their low early strengths. Rapid quenching of molten slag is required to produce æhydraulically-activeÆ binder when reacting with OPC; but water quenching can also require between five to ten tons of water per ton of slag at the plant. æDryÆ granulation (atomisation) is emerging as an alternative technology, the resulting solid product does not require drying, and possibilities exist for recovering heat energy from the hot slag.CSIRO Minerals has well-developed skills and equipment in pilot-scale pyrometallurgical treatment, and granulation of molten slag, including traditional wet, and also dry methods. Techno-economic desktop studies can also be used to help quantify factors such as value-adding of treated waste products, potential reductions in CO2 emissions and carbon credits, reductions in water consumption, and the possible decreased energy costs associated with fine grinding of dry slag granulate.The authors will present preliminary results from slag atomisation/dry granulation testwork (0.5 - 2.5 kg scale) and associated modelling studies, conducted using a æsyntheticÆ and industrial ironmaking slag. Outcomes from a techno-economic study on production of cement utilising wet or dry atomised slag granulate will also be discussed in detail.

Jan 1, 2004

By E R. Ramanaidou, C Tessarolo, M Verrall

Garnierite mineralogy in saprolitic ore of the Goro lateritic nickel deposit, New Caledonia , was investigated using X-ray diffraction (XRD), optical and scanning electron microscopy (SEM) and electron microprobe (EMP) analyses. These conspicuously, green-coloured phases occur either as submillimetre to centimetresized veins or as æbookletsÆ arranged in, macroscopic (subcentimetre sized), accordionlike structures supported in an undifferentiated matrix of mixed ÿ7+ and ÿ10+ phases. Within the veins, nickel for Mg solid solution increased from ten wt per cent NiO at the edge to 34 wt per cent NiO at the core, with vein edges comprising Ni-kerolite with <1.5 Ni per formula unit (pfu) grading to pimelite containing >1.5 Ni pfu at vein cores. The æbookletsÆ comprised nTpouite of formula, (Mg0.67Ni1.59Fe3+0.05)(Si2.17Al0.22)O5(OH)4 and averaged 30 per cent NiO. SEM element mapping highlighted the distribution and mineralogical association of Ni and Mg and emphasised the inverse relationship between Ni and Mg at the macroscopic (thin-section) scale. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008