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The main factors controlling the electro- winning of zinc from impure aqueous sulphate electrolytes are reviewed. Zinc, hydrogen and impurities are deposited at the cathode. The current effic- iency for zinc is increased by increasing zinc/ acid ratio and current density and by decreas- ing temperature; and may be unchanged, increased or decreased by the presence of impurity ions. A qualitative comparison of observed and predicted impurity effects is in reasonable agreement. Quantitative treatment of the effects of impurities and cell additives is not available. A tentative explanation of the time dependence of current efficiency in the presence of some impurities is provided. The forms in which impurities are deposited is substantially unknown. Impurities may be classified according to the extent of cathodic deposition. Procedures for control of cathodic deposition of impurities are outlined. The main anodic reactions are the forma- tion of oxygen, manganese dioxide and sulphuric acid. Minor reactions include the oxidation of lead, silver, cobalt and chloride. The site of the anodic reactions and the reactions generat- ing manganese dioxide are uncertain and may change with time of operation. The anode behaves crudely as an oxygen electrode with

Jan 1, 1977

The Mineral Resources Act 1989 was assented to on 25th October, 1989 after more than two years of consultation and negotiation between Government, the mining industry and other affected parties particularly the major rural organisations.The legislation proposes major conceptual changes in a number of areas and adopts a totally new approach to the definition of land and the mechanisms available to the mining industry for accessing such land.Unfortunately the passage of the legislation through Parliament coincided with the lead-up to the State election. Ultimately it became an election issue generating much adverse comment in the media particularly from rural and landholder groups. It was obvious that much of this anti-mining propaganda resulted from a lack of understanding of the legislation and the benefits that flow to the majority of landholders as well as the mining industry.It is essential that the contents of the Mineral Resources Act be thoroughly understood by all parties. Only then will all the State's resources be able to be developed in a multiple land use environment.This paper outlines the philosophy behind the new Act and the more important provisions contained therein.

Jan 1, 1990

By Allen RL, Clifford BA, Wright JV, Bull S

The Bunga Beds of the Late Devonian - Boyd Volcanic' Complex is a well exposed succession of rhyolite, sedimentary rocks and minor basalt outcropping along the south coast of New South Wales. The sedimentary rocks vary from shallow water basin margin facies, to deep-water basin centre facies, and the majority of .the volcanics are associated with the deep water facies association. The volcanics are dominated by rhyolite domes, lavas and cryptodomes, whose margins are extensively autobrecciated and quench fragmented. In situ pyroclastics represent a very minor volcanic component and are restricted to the remnants of two small doors- top tuff cone successions. Pyroclastic debris is common in the sedimentary succession enclosing the volcanics and was clearly derived from shallow to emergent basin margin areas through mass-flow redeposition. The succession has bearing on the origin of the fragmental component of, the volcanics that host Kuroko- type massive sulphide deposits. The characteristics of these fragmental volcanics are not well documented. We suggest that based on the Bunga Beds,'Kuroko-type volcanic successions are dominated by coherent rhyolite/ felsic lavas and intrusive domes, autobreccias and hyaloclastites, that in situ pyroclastics are rare or lacking, and that redeposited volcanic debris is abundant. Pyroclastic debris is most likely to have been derived from shallow areas marginal to the deep-water volcanic centre that produce the Kuroko-type volcanics and sulphides.

Jan 1, 1987

By J P. R de Villiers

The Vanderbijl Park sinter plant in South Africa was investigated to determine the reason for the production of very fine sinter not acceptable as feedstock for the blast furnace. A procedure was designed to generate representative samples and to prepare the samples for chemical and mineralogical analyses. Results from a mineral analyser showed that the samples are extremely heterogeneous and therefore the sampling and sample preparation methods had to be tested in order to produce representative samples. The high production capacity at the sinter plant could also give rise to sampling errors. The method designed involved sampling of the conveyor belt at the sinter plant every four hours for the duration of three days. The samples were then milled and split into smaller sections appropriate for analysis. X-Ray diffraction (XRD) and X-Ray fluorescence (XRF) analyses were conducted on the samples. The results showed a standard deviation of less then one per cent, which indicates that the samples were representative and that the method used was therefore adequate. Systematic differences in the phase proportions between normal and fine sinter samples were detected, with the fine sinter containing more haematite than the normal sinter. The sampling method employed gives added confidence that the differences are real.

Jan 1, 2008

By N R. Johnson

The overland conveyor at the Los Pelambres mine in Chile is designed to move 8700 t/h of material over 12 km at a speed of 6 m/s while descending 1400 m. The conveyor, which is divided into three segments, is equipped with a braking system that must bring it to rest without producing excessive stresses in the conveyor belt. Retardation and gently stopping a mass of 250 t requires retardation times in the order of 60 seconds. Brakes that can provide this performance require sophisticated controls as well as very high heat absorption capacity. This paper describes the thermal analysis of the braking system, which required the use of novel materials to meet the arduous duties imposed on the callipers and discs.

Jan 1, 2005

In presenting size analysis data, one has the choice of various graphical techniques; each no doubt has been developed to highlight a particular aspect of the data. A frequency size distribution plot is used quite extensively to illustrate the importance of the finer size particles in iron ore granulation. However, the basis for such a plot is often not appreciated. As a result, cases of incorrect use can be cited. The aim of this paper is to extend the work of Alien (1981) and to provide, using examples and figures, a basic understanding of the implications of the various size distributions. A simplified method of presenting sizing data on a linear scale graph paper is presented and recommended. This involves a simple construction of a histogram of mass fraction versus particle size (in geometric progression).

Jan 1, 1992

By Boyce WH

Earthquakes are the most frightening and devastating natural phenomena known to mankind. They strike without warning and their consequences can be disastrous in terms of the toll of human life, financial crises related to the damage or destruction of man-made structures and the social and economic effects on a wide spectrum of the affected communities in the aftermath of the event. Such situations can be widely attested to by most areas around the Pacific Rim. Indeed, the threat of earthquakes is always imminent because of the geological-tectonic nature of the region as manifested by past experiences. It is patently obvious that earthquake occurrences are not only a geological hazard but also pose a serious social danger. When one considers the 19 September 1985 Mexico (Michoacan) earthquake (Mitchell at al., 1986), the necessity of continuing research is of paramount importance. An estimation . of earthquake risk encompasses both qualitative and quantitative aspects and demands a multidisciplinary research effort integrating seismology, tectonics, geology, enginering, sociology, economics, insurance and governmental policies (Bolt, 1978; Booth, 1984). These roles in mitigating such a hazard have been aptly discussed by Press (1985). A series of discussion papers based on an intergovernmental conference covering the whole scenario were published by UNESCO (1978). A comprehensive case history was provided through a workshop on the 1886

Jan 1, 1987

A review of publicly available coronial inquiries into fatalities that have occurred within the resources sector since the year 2000 reveals that a loss of corporate memory has been a contributing factor in 40 per cent of these accidents (National Coroners Information Service, 2010, Appendix B). With the highest levels of employee turnover within the Australian economy, increasingly complex operations and an ageing workforce, the management of corporate memory within the Australian resources industry poses a significant and often unrecognised safety risk.    The North Parks airblast of 1999 is used as a case study to highlight how corporate memory loss poses a significant hazard to resources projects and how such incidents will continue to occur if corporate memory is not effectively managed. Best practice from other industries is discussed to demonstrate how knowledge management systems can effectively work. This paper discusses how systems can be put in place within the geographically diverse resources sector, and how at the heart of any knowledge management system a culture of knowledge management needs to exist within an organisation.   The paper then discusses the importance of retaining key personnel and utilises findings from primary survey data collated in 2009 to show the size of the retention problem within the industry. From the data possible solutions to retaining key staff are proposed.   Finally the large and increasing role of contractors and consultants within the industry is discussed and methods of managing their knowledge are proposed.

Jun 1, 2010

The resistance of lead to chemical attack and the ease of its fabrication has made it one of the most useful of the metals available to the chemical engineer and the electrometallurgist. It has proved to be of particular value in the manufacture of sulphuric acid, and since the conversion of the sulphur of pyritic ores into sulphuric acid is becoming the duty of the metallurgist, the corrosion resistance of this metal will be a matter of considerable interest to him from the standpoints of both producer and user. He realises that there is little to be gained in carrying the process of purification past the ordinary economic limit if little or nothing is to be added to its corrosion resistance, and he as user would not be willing to pay a premium for such purification if it can be shown that its reputed value has no scientific foundation.The metallurgist is well acquainted with the trouble and expense of meeting demands which have nothing torecommend them but prejudice and fancy. The valuable anti-corrosive properties of lead are very commonly ascribed to its forming insoluble compounds with the acids sulphuric, hydrochloric, carbonic, etc. If we trusted superficial visual evidence alone, such a view would receive strong support, but in the light of what we know of the mechanism of corrosion we must attribute its resistance to other factors much less obvious to casual inspection. Certainly there may be some mechanical obstruction set up to diffusion of the liquids towards the surface of the metal.

Jan 1, 1932

Scientific drilling and blasting techniques are currently being presented to the mining industry as an aid in the overall optimisation process. The degree of success in the development of these techniques over the last ten years has prompted statements that generally relate to blasting becoming a science rather than an art. Many of the techniques are currently operated or at least analysed by scientists. As such, their use has been restricted to project type activities while the more routine activities associated with day to day mining has continued to be carried out by engineering rather than scientific staff. Some of the scientific techniques will remain legitimately as a project or an occasional use facility. Generally speaking a cost/benefit analysis at a particular mine will decide the level of use. This should logically highlight a number of techniques with potential of regular mine site use. Regular mine site use implies mine site analysis and hence the gulf between the scientist and mine operator/engineer must be addressed. There are all sorts of solutions and they are not mutually exclusive. One alternative could be to increase specialisation at the mines. With "career paths" becoming more formalised the trend would seem to be away from mine site specialists unless, for instance, this specialisation was provided by term secondment from research establishments. Another alternative could be the scientists themselves applying their developmental skills to "humanise" and "package" the projects in such a manner that they can be routinely used at mines.

Jan 1, 1990

Citigold Corporation operates the Warrior gold mine at Charters Towers, northern Queensland, mining narrow quartz veins (0.1 to 2 m wide) in granodiorite by long hole open stoping on levels 15 m apart. Access is by decline and cross-cuts with on-ore development drives. The mineralisation comprises Palaeozoic mesothermal quartz veins containing gold, pyrite, sphalerite and galena, hosted by the Ordovician age Towers Hill Granite. The gold grain size is variable from 1 to 500 ¦m with 1 m face samples up to 800 ppm Au, and average run-of-mine grades of 10 to 14 ppm. Despite the spectacular gold tenor, little visible gold is present. Gold grades are highly variable presenting challenges in ore reserve estimation. Tonnages are discounted by 70 per cent to allow for the low payabilities (30 to 50 per cent) of the veins. Estimation techniques allow high confidence in overall global grade estimates but poor reliability on a local scale (25 m). Kriging ranges as low as 5 - 8 m means that obtaining a Proved Ore Reserve by diamond drilling is not economically feasible, and broad-scale mine planning decisions are made at the Inferred Mineral Resource stage and mine design work at the Probable Ore Reserve stage. Proved Ore Reserves can only be estimated after underground development has proceeded through the mineralised body with levels at 15 m vertical spacing sampled at 2 - 3 m intervals along the level. However, reconciliations between actual gold produced and earlier resource estimates produce workable results. A further three mines are scheduled to be developed underneath the city of Charters Towers.

Jan 1, 2008

By M Noppe, I Glacken

There are many critical nodes along the mine value chain, from orebody to mineral product, and inter-disciplinary input is required to analyse the variability and uncertainty at each node in order to identify and mitigate areas of risk. Mining differs from many other industries in that the variability in the product is dictated largely by the inherent nature of the input material (the orebody). The true characteristics, including the variability of the orebody, are never known exactly and are instead based on estimates derived from sample data. A further difference is that bottom-line gains are largely controlled by world commodity prices, which can vary with time, rather than by local supply and demand issues. Methods for identifying, reporting and responding to this inherently variable raw material are discussed. These include analytical and reporting methods, equipment and software, risk analysis and reality checks (eg reconciliation). Sampling results, mineral resource and ore reserve estimates and economic assumptions are a function of the variability of the orebody. Risk quantification should be expressed as a level of confidence, which takes into account the scale or period over which the risk is being assessed (life-of-mine, annual or shorter production periods) and should convey the likelihood, severity and consequence of occurrence of a given event. The future generation of mining specialists needs to understand the entire mine value chain to better manage risks and maximise mine dollar-value.

Jan 1, 2002

By P Cepuritis, G Chitombo a, I Brunton

There is a significant amount of past evidence that links blasting and occurrences of slope failure. Particularly of great concern at Telfer Gold Mine is the effect of open pit blasting on the stability of the footwall slope above the underground portal and the stability of underground structures. For this reason, Newcrest Mining Ltd invited JKMRC to conduct necessary field measurements and numerical modelling with the following objectives:assess the dynamic stability of the footwall slope above the portal; assess the characteristics of current and future blasts in the open pit; and prepare open pit blasting guidelines that will minimise the detrimental effect of blasting on slope stability. To achieve these tasks it was necessary to develop a scaled distance attenuation curve for blast vibrations. In order to validate the developed vibration attenuation curves it was necessary to monitor vibrations from a production blast. Using JKMRC blast design software tools, the vibration of the production blast was also modelled from the blast design and vibration results from single hole blasts. The intention was, assuming that the observed and modelled vibrations were close in terms of frequency and amplitude, to use the software tools to model the vibrations of future blasts and assess their likely effect on slope stability. Numerical modelling of the dynamic stability of the footwall slope was done using the FLAC finite difference code and the UDEC distinct element code. The results of the numerical modelling and of the field measurements of the blast induced ground vibrations were combined into the blast design rules that relate distance between the slope and the blast, charge weight per delay and number of blasts necessary to cause failure of the slope.

Jan 1, 1999

During 1995 a catastrophic accident took place at the No 2 Vaal Reefs shaft in South Africa, when a locomotive fell onto a cage, causing the death of 104 people. The subsequent Commission of Enquiry found that the safety detaching hook had opened when hit by parts of the falling locomotive, detaching the cage from the rope and allowing the cage to drop 400 m down the shaft. It was believed that had the hook not detached, the rope would have been sufficiently elastic not to have failed, implying that many fatalities may have been avoided. In addition, the risk of accidental opening of hooks due to impact with smaller falling objects in shafts became a concern. This paper deals with a comprehensive statistical investigation that was performed to quantify this risk, establish acceptable levels of such risks and to derive criteria for the resistance of detachment hooks against accidental opening caused by impacts. The investigation involved a survey, dynamic finite element analyses and Monte Carlo simulations.

Jan 1, 2005

By S Paciornik

The traditional trading of iron ores is based on chemical specifications and particle size distribution. However, recent characterisation studies, that bring additional information like mineralogical composition and microstructural (textural) aspects, have become important. They contribute to determination of the iron ores downstream beneficiation operations and subsequent steelmaking processing, allowing improvements on both new and existing processes. Despite progress in commercial scanning electron microscope/energy dispersive spectrometer (SEM/EDS) automatic instruments in the last decade, these systems are not capable of performing the identification and discrimination of major iron ore minerals (haematite and magnetite) and the consequent description of its microstructure. On the other hand, reflected light microscopy (RLM) can easily distinguish the iron oxides by their reflectancies, but it cannot discriminate quartz and epoxy resin, which present similar colour on images. The present work proposes an innovative method to perform a quantitative mineralogy characterisation of iron ore based on RLM-SEM co-site microscopy. This technique combines images obtained by RLM and SEM through an automatic registration procedure that accurately aligns the two kinds of images of each field. In fact, it creates multi-dimensional images, which are then analysed using image processing and pattern recognition techniques. The case study is an itabiritic iron ore from Quadrilßtero Ferrffero (Brazil) which contains mainly quartz, goethite, magnetite and haematite. The discrimination of phases that are not distinguishable with either RLM (epoxy resin and quartz) or SEM (haematite and magnetite) can be performed through this multimodal approach, allowing the subsequent mineralogical quantification. The mineralogical quantification computed by image analysis was consistent with independently obtained results based on the Rietveld technique.

Jan 1, 2008

By Skinner J, Brackenbury K

The AuPlus" Systems have been applied in the gold mining industry to achieve improved gold recoveries, faster leach kinetics and reduced cyanide consumptions. Calcium or hydrogen peroxide, collectively known as peroxygens, can be used. The choice depending on plant design and the nature of the ore. Laboratory test work and plant trials are included in this paper to illustrate the benefits of peroxygen usage in extractive gold metal- lurgy.

Jan 1, 1991

Mineral resource classification is essential because it is required for public disclosure. The resources must be binned by a qualified person into measured, indicated and inferred categories using an appropriate methodology. The classification methodologies used have long been a topic of research and discussion. There are various traditional and geostatistical methods used in practice. Some are more popular than others. Because of the uniqueness of each ore deposit, it seems almost impossible to have a single industry-accepted norm for mineral resource classification. Therefore, some experts have adapted the methodologies tailored for the deposits they are working on, but many simply use the methods they and their clients understand and are comfortable with. In this paper, a new approach is presented to classify the mineral resources using a data geometry index. This index combines both traditional and geostatistical aspects of resource classification based on the data configuration around the block interpolated. It is a function of several variables such as kriging variance calculated for a block, distance from the block to the nearest sample and the average distance of all samples used to interpolate the block. Thus the approach using this index takes into account the spatial data configuration around the block being estimated, as well as the traditional distance criteria. The data geometry index and how it is calculated is explained. A case study for a gold deposit is presented to see how the classification based on this index compares to the existing methodology used in this deposit for mineral resource classification.

Sep 26, 2011

By J Galvin

This paper addresses the actions of the Australian mining industry, its regulators and educational providers towards ensuring that a pool of competent mine managers is maintained in Australia and that mine management remains a desirable career path for future mining professionals. The Australian and global mining industries are experiencing an acute skills shortage. Mine managers, traditionally drawn from the ranks of mining engineers, are at the sharp end of this shortage. Exacerbating the shortage is a perception that a professional mine manager is not an attractive career option. This perception is influenced by the following forces which combine to make the role of a modern mine manager very demanding:legislative requirements for owners and managers to ensure (guarantee) the safety and health of employees; an increasing trend towards prosecution over exposure to risks to health and safety a need to be more aware and responsive to community and environment; financial, technical and æpeopleÆ pressures traditionally associated with the job of managing a mine; and mine management roles being filled by younger and less experienced professionals. Universities and other educational providers have the challenge of both ensuring that undergraduates are exposed to these issues during their study and continuing to promote mine management as a desirable career option. Anecdotal and statistical evidence indicates that young graduates are choosing and remaining in technical roles rather than taking on the challenge of mine management. Furthermore, it is suspected that the issues referred to above are contributing to the low retention rate of young professionals at mine sites. The challenges are not insurmountable, however. This paper reviews the initiatives of industry, the regulators and educational institutions in addressing these challenges. It includes a focus on:prosecution policies and their impacts, tertiary education program content and delivery modes, CPD initiatives of the Mine Managers Association of Australia, and alternative pathways for obtaining mine management qualifications.

Jan 1, 2006

By Polthier K

A short discussion of the salient aspects of a dispersed flow model in relation to the gas flow in blast furnaces is given. The use of the theory in assessing vessel performance is mentioned. Tracer results of a blast furnace (688 m3) from three furnace levels and different radial positions are analysed and results presented as D/ud values. The significance of the shapes of experimental tracer curves are included and comparison is made with results obtained on other furnaces.

Jan 1, 1975

By A E. Waltho, W J. Shaw

Predicting the physical characteristics of various ore types has for long been a difficult problem during mining. Grade control practices tend to concentrate on the chemical grade of the ore. Estimation of physical characteristics such as beneficiation behaviour is commonly limited to the simplistic application of historical averages. Large amounts of geochemical data are often gathered during the exploration and mining stages of a project, especially in ferrous and base metal deposits. In addition to the elements of principal economic interest, samples are often analysed for suites of gangue constituents to determine whether the mineralisation lies within target specifications. This multi-element data is often put to no other use than this simple chemical classification, yet it may present the geologist or metallurgist with valuable insights into the mineral content and physical characteristics of the deposit. Normative mineral estimates have been used as a method for characterising igneous rocks for almost 100 years. The method establishes and applies a set of sequential rules, by which the chemical components of a sample are assigned to mineral components. Provided that it is possible to make some realistic assumptions about the mineral species likely to be present in a rock unit or deposit and their paragenesis, this approach can be extended to a variety of mineral deposits. The geochemical data that are routinely collected when, for example, drilling iron ore and base metal deposits, can be used to derive estimates of normative mineral content. These estimates can be used to characterise physical or metallurgical aspects of the ore, such as density, beneficiation behaviour and metal recovery. This paper examines the application of normative mineral estimates to a variety of practical resource characterisation problems. The potential for predicting the lump and fines proportions of iron and manganese ores is also discussed.

Jan 1, 1999