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By Happ J. V

Factors affecting the rate of arsenic removal from lead bullion during softening processes were studied. Very high rates of removal could be obtained under conditions of intense agitation and ready availability of oxidant. Reaction mechanisms were proposed to explain the sequences observed. Selective removal of arsenic with minimal loss of antimony from bullion was favoured by a low temperature Harris process and oxidizing via a caustic soda medium.

Jan 1, 1987

ALTHOUGH the development of the various flotation processes during the last 8 years has been so revolutionary, this development has been, until recently, entirely confined to the separation of the gangue from the mixed metalliferous sulphides.The desirability of finding some method of separating the independent sulphides from such a miXture, by means of flotation, has long been recognized. ThIS need was emphasized when the slimes resulting from the grinding of Broken Hill sulphide ores were for the first time successfully dealt with by the Mineral Separation Company's process on the Central mine. This process proved the practicability of separating the sulphides of lead and zinc as a mixed concentrate from the gangue present in slime. Although this was a very notable achievement, the process has not been generally used, owing to the mixed lead and zinc concentrates resulting from the treatment being acceptable neither to the zinc nor the lead smelters.Although the introduction of eucalyptus oil in minute quantities as an emulsifying agent has simplified the work of the subsequent tabling of mixed sulphide concentrates, rendering unnecessary the burning off or removal of the oil, there will always be a considerable quantity of slimy product too fine to settle on the moving surface of the concentrating machines, and therefore requiring other means for its division into lead and zinc concentrates.

Jan 1, 1911

AustraliaÆs record-breaking drought, efforts towards environmental best practice and the current commodities boom is demanding water use and reuse as never before. Mining practices, processing, the remote communities and support industries require vast amounts of specific quality water. Sustainability of water use has been a key factor in mine development, expansion of existing operations and increasing profitability of processes involving water. Developments in water treatment technology have enabled the use of a range of processes to produce this water reliably at ever decreasing costs. This increasing acceptance of new technologies has seen seawater desalination, recycling of plant wastewater streams, municipal wastewater reuse and others to become commonplace. Processes including seawater and groundwater reverse osmosis (RO), low pH RO, thermal desalination, high rate clarification, brine water treatment, ion exchange and other advanced treatment technologies are now used as part of mining operations. This paper surveys the trends in water treatment for the mining industry both in Australia and internationally with a review of technologies and case studies of operating plants. The key technologies are explained with an emphasis on the specific requirements for mining operations û unusual raw water, process and operations limitations, environmental concerns, as well as harsh climate. Case study information from several mining operations is included.

Jan 1, 2006

By Wadsley MW

The Greenhouse Effect, with its potential for global warming, is strongly linked to industrial carbon dioxide emissions. Global carbon mass balances indicate that absorption in sea water is the major natural sink of carbon dioxide. However the surface waters of the oceans are close to chemical equilibrium with the atmosphere with respect to carbon dioxide, while the deep ocean waters are not. Consequently, the transfer of carbon dioxide from the surface limits the rate at which the oceans can absorb carbon dioxide. It is proposed that direct transfer of carbon dioxide from industrial installations to deep ocean waters be evaluated as an interim measure to slow the rate of increase of carbon dioxide concentration in the atmosphere and hence allow time for the development of sustainable industrial practices. As an aid to thinking on the development of suitable technology, equilibrium calculations are presented which demonstrate that sea water in equilibrium with flue gases will dissolve six times the quantity of carbon dioxide that is dissolved in equilibrium with the ambient atmosphere. Sea water saturated with calcium carbonate and in equilibrium with flue gases will dissolve 20 times the quantity of carbon dioxide that is dissolved in equilibrium with the ambient atmosphere. However the absolute concentrations of dissolved carbon dioxide are still very small.

Jan 1, 1989

By S McKnight, S Hall

Much of the research regarding the use of bacteria for the oxidation of sulfide minerals has been conducted using pure bacterial strains or synthetic minerals, often under ideal conditions, which does not reflect the conditions commonly encountered in commercially operating plants. This has also led to much conjecture as to the exact mechanism by which bacteria are able to enhance sulfide oxidation and as to which species of bacterial microflora are the most dominant. Recent advances in 16S rNA sequencing has confirmed that many of the bacterial species once thought to dominate commercial oxidation circuits were simply more willing to grow under the culturing conditions used and may only play a minor role in the oxidation process (Rawlings, 2002). Consequently this research will look at bacterial oxidation under conditions more reflective of commercial operations, focusing on the presence of organic carbonaceous material within a refractory sulfide orebody to be sourced from the Fosterville deposit of Perseverance Corporation Limited.

Jan 1, 2004

Chief Geologist, Groundwater and Engineering Geology Branch South Australian Department of Mines and Energy The six papers submitted for consideration during this session include two dealing with techniques for measing rock mass behaviour, including permeability, in boreholes, one describing the use of surface geophysical methods to delineate pollution plumes in groundwater together with analytical modelling of the plume, and one presenting a biological tracer technique applied to the determination of the origin of water entering underground mine workings. A paper describing dewatering at a base metal mine in Queensland includes an account of the investigation techniques employed to establish a conceptual model as a basis for the evaluation of various dewatering strategies. Of considerable interest is the use of a field gravity survey to delineate a zone of highly weathered rock which forms the major aquifer at the site.

Jan 1, 1988

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 A Weeks an, R Bertinshaw, S Khosrowshahi

Good mining is central to any approach to value tracking. Good mining occurs where the ore is correctly delineated, measured and fed to the mill. This process is usually referred to as grade control, ore control or quality control. There are now ways to measure the efficiency of this process, such as by using conditional simulation, and a brief synopsis is presented. Resource estimation is the foundation of ore reserve estimation, which should enable useful prediction of the expected metal to be recovered from mining and milling. Significant improvements have resulted from applying new techniques such as the Chain of Mining (CoM) method, which models the mining process. Again, a brief synopsis is presented. Tracking value from the mine through the mill implies a linear sequence of processes that can be modelled. Reality is more complex and there are error components, feedback loops and breaks in the Chain of Value. Modelling the total production process in a number of operations is considered, including the various impacts on producing reconciliations. Procedures are also discussed for handling a number of difficult issues such as: different data supports, stockpiling strategies, blending from multiple ore sources, blast movement and underground ore extraction.

Jan 1, 2002

The Committee for Mineral Reserves International Reporting Standards (CRIRSCO) was formed in 1994 to promote development and adoption of international standards for estimation and reporting of exploration results, mineral resources and mineral reserves. The CRIRSCO standards have been accepted by most mining companies and professional societies worldwide. Market regulators from Australia, South Africa and Canada require that these standards be followed when releasing public information. Among these requirements is the use of specific definitions for what constitutes exploration results, mineral resources and mineral reserves. If such information is publicly disclosed in must be estimated by a Competent or Qualified Person. In the United States of America, public disclosures are regulated by the US Securities and Exchange Commission. The SEC does not recognise the CRIRSCO guidelines, and some of the SEC requirements for public release of information are materially different from those applicable in other countries. The CRIRSCO definitions and the Competent Person requirements are reviewed and compared with those of the SEC. The organisation of the SEC and its rule making process are briefly discussed. Ongoing efforts to bring the US regulatory requirements closer to those applicable in other countries are presented, as well as other activities that CRIRSCO is entertaining with the United Nations, the International Accounting Standard Board and other international organisations to reach the objective of worldwide standardisation of reporting procedures.

Jan 1, 2006

By Moorrees C

Carbonic acid leaching of crude iron-containing magnesia derived from Savage River magnesite yields a magnesium bicarbonate leachate with a substantial soluble iron concentration. The iron concentration depends upon the leaching conditions (particularly time, temperature and pulp density) but is generally in the range 0.005-0.5 g/litre. If this soluble iron is not removed prior to the precipitation of the magnesium as a hydrated carbonate, then this product will be contaminated by the iron, and will not yield a final product (high-purity magnesia) that meets specifications.The soluble iron content of the magnesium bicarbonate leachate can be reduced to an acceptable level by addition of solid aluminium sulphate either during carbonic acid, leaching of the crude calcine or to the clarified leachate. Chemical analysis and X-ray diffraction revealed that the iron is precipitated as an iron-containing hydrotalcite-type compound, [Mg6(Al,Fe)2(OH)16]CO3.4H2O. The actual composition of the precipitate depends on the amount of aluminium sulphate added and the precipitation technique used. Because precipitation of iron in this manner also results in reduced magnesium recovery from the leachates, It WIll be necessary to develop methods for recovering the magnesium component of the precipitates.

Jan 1, 1984

By S C. Goel

The Obuasi Mine in Ghana, West Africa is the largest producing gold mine in Africa, outside South Africa. The mine has changed from a mine producing from narrow vein, high grade quartz orebodies to a mine producing from wide, lower grade sulphide rebodies. Traditionally mining methods were cut and fill and sublevel caving. Now the preferred stoping methodologyis long hole open stoping. Transverse or longitudinal methods are both used, dependent on the orebody characteristics. The change has been technically, socially, economically and politicallychallenging and at times has tested the abilities of those responsible for the operation of the mine. However, the benefits have been many. Safety has improved significantly, ounces from underground have doubled. Productivityhas doubled and underground unit costs have reduced bya third. These achievements have allowed the Obuasi mine to staycompetiti ve in this time of falling gold price. During 1999 and 2000 a full review of the mining and processing operations was undertaken, and as a result, the mine is now in a phase of restructure. Efforts are being made across the mine to improve efficiencies and to reduce costs. The future for the Obuasi Mine is an exciting one.

Jan 1, 2000

The problems of the as-built water supply system are discussed. Recent modifications to the collection dams and the water cleaning station using wedge wire screens to resolve these problems are outlined.

Jan 1, 1978

By Sneyd R. J, Walton M. C

In early 1987 Minproc acquired a license from the inventor to engineer and construct acid plants incorporating the Fattinger technology. The process offers a simple and reliable method of producing sulphuric acid from metallurgical off gases at significantly lower capital and operating costs than the more familiar contact process. The process also offers the simultaneous production of nitric acid, if the NOx content of the off gases is high enough. A development of this latter process has other applications within the minerals industry, particularly in conjunction with refractory gold ore preoxidation.

Jan 1, 1989

The latent conditions clause in various general conditions of contract have traditionally proved to be a source of significant disputes in tunnelling contracts, even when extensive geotechnical investigations have been carried out at the tunnel site and a report of these investigations provided with the tender documents, informing the contractor of the nature and extent of subsurface conditions likely to be met with during execution of the works. This paper discusses the contractual aspects of the new latent conditions clause in the recent Australian Standard AS 2124-1986, General Conditions of Contract, in relation to tunnelling contracts. A comparison of this new clause is made with other latent conditions clauses in general conditions of contract in use in Australia and other commonwealth countries. It is seen that the new latent conditions clause in the recent Australian Standard 2124-1986 has, by providing for a reasonable apportionment of risks, attempted to minimize contractual disputes relating to latent conditions in tunnelling contracts and to provide a satisfactory basis for quick and efficient settlement of such disputes should they arise during execution of these contracts.

Jan 1, 1987

An efficient filtration plant can be designed only from an adequate knowledge of the filtration characteristics of the material to be handled; if these characteristics can be expressed in the form of an equation the work of design is simplified immensely. The literature of the subject contains numerous equations which have been developed by various workers to express their results, usually obtained from a 'Very limited class of material, and from moderately thick pulps. Such expressions have been found quite unsuited for use in the case of thin, very free filtering pulps.In 1926, Underwood put forward an equation having a general for m, and which, he was able to show, provided a satisfactory expression of the data obtained and published by a large number of earlier workers. This equation has been found a very satisfactory and useful tool for the study of a variety of filtration problems. As thel basis of the equation is of assistance to the understanding of subsequent discussion, a brief account of Underwood's derivation is given here.UNDERWOOD's FILTRATION FORMULAEThe following symbols are used:

Jan 1, 1932

As I drove in from the airport on Sunday somebody said `On the right you will see Dun- troon, which is the military training school of Australia.' So I asked the driver, where did they get that name? `Oh,' he said, `from some people who built a house there. That was it's name- Duntroon.' It strikes a note with me because, that's the name of a 12th century castle on the west coast of Scotland where I spend what leisure hours I have and, therefore, it establishes the long connection between Australia and my native land. There is also a story I should tell you about the oil industry and its upsurge in Scotland recently which has resulted in great prosperity. And in Edinburgh, the walls of the banks are bulging-because of the incursion of foreign exchange and other resources.

Jan 1, 1978

By M Yahyaei, M S. Powell

Mineral processing plants have become large and complex, generally through progressive expansions. Addition of a pre-crushing stage to conventional Semi-Autogenous-Grinding (SAG) and ball mill - crushing (SABC) circuits has introduced a complex materials handling system coping with +200 mm particles. Application of High Pressure Grinding Rolls (HPGRs) and implementing hybrid comminution circuits (ie, HPGR-SAG mill) requires proactive control of the feed size distribution to each unit. Application of Vertical Tower Mills (VTMs) and other fine grinding equipment to achieve a finer grind size, while maintaining the throughput, requires splitting the feed evenly between parallel units. Many of the conventional comminution circuits (ie, staged crushing and screening followed by staged ball milling) must deal with the transition from open pit ore, which is generally altered and soft, to underground ore, which is intact and hard, requiring existing crushers to produce a finer product to unload the ball mills.This paper presents common process improvement opportunities which have been identified during a number plant process reviews conducted by the authors in Australian and international operations. The operation of comminution circuits to known and accepted standards, which is explained in this paper, could improve the performance of circuits by between 5 and 10 per cent, generally at no capital cost and often at a lower operating cost. The performance improvement can be realised as throughput increase, a finer product size, or reduced operating costs (ie, energy saving, low maintenance, less consumables).Process optimisation opportunities presented in this paper include: enhancing materials handling and storage to avoid segregation; standard operation of screens to reduce misplaced materials; proper feeding arrangement and control of crushers to increase their utilisation; preparing proper feed for SAG mills to reduce grind size; splitting the feed evenly between parallel equipment to improve utilisation, and controlling operation of classification units to improve energy utilisation.CITATION:Yahyaei, M and Powell, M S, 2018. Production improvement opportunities in comminution circuits, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 233–248 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By B Olsson, R Norman, M Volz

Australia has seen unprecedented demand for coal exports in the last ten years and this demand is set to expand further still according to many analysts. This rapid increase in demand has placed pressure on multi-user coal chains to guarantee the capability to meet the required demand, in terms of both current operations and capacity expansion.The projects required to deliver these forecast tonnages take place in an increasingly complex commercial and technical environment. These challenges include brownfield and greenfield projects, multiple rail and terminal service providers as well as a myriad of mine operators, all needing to operate in an increasingly integrated manner to get the most out of expensive shared assets.Increasing complexity and integration drives the need for more holistic and sophisticated analysis tools. The capacity of coal chain subsystems, such as mine, rail and port, can no longer be determined effectively in isolation. Understanding the nature of the interactions between these subsystems and the resultant capacity of the integrated system is the key to maximising value. TSG advocates the use of a total integrated system approach to understand the behaviour and performance of complex coal chains.Recently, TSG has worked in conjunction with the Integrated Logistics Company and a number of stakeholders in the Dalrymple Bay Coal Chain to deliver the first independent system master plan. This master plan has provided a quantitative and rational assessment of coal chain capacity in its current state and a prediction of its capacity once a pipeline of committed capacity improvements is in place. It is underpinned by a highly detailed discrete-event simulation model of the complete coal chain as an integrated system, including mine load-outs, rail, terminal and port operations.This paper provides an overview of the study and describes the differences between subsystem and total integrated system model performance.

Sep 26, 2011

By F Minz, P Lamberg, A Mwanga, C Lund, C Wanhainen, M Amiri Parian, J Rosenkranz

A geometallurgical model is currently built in two different ways. The first and the most common way relies on geometallurgical testing, where a large number of samples are analysed for metallurgical response using small-scale laboratory tests, eg Davis tube testing. The second, mineralogical approach focuses on collecting mineralogical information over the orebody and building the metallurgical model based on mineralogy. At Lules University of Technology, Sweden, the latter method has been adopted and taken further in four ongoing PhD studies. The geological model gives modal composition by the help of element-to-mineral conversion and Rietveld X-ray diffraction. Texturally, the orebody is divided into different archetypes, and liberation measurements for each of them are carried out in processing fineness using IncaMineral, a SEM-based technique. The grindability and liberation spectrum of any given geological unit (sample, ore block, domain) are extrapolated from the archetypes. The process model is taken into a liberation level by mass balancing selected metallurgical tests using the particle tracking technique. The approach is general and can be applied to any type of ores. Examples of ongoing studies on iron and massive sulfide ores are given.CITATION:Lamberg, P, Rosenkranz, J, Wanhainen, C, Lund, C, Minz, F, Mwanga, A and Amiri Parian, M, 2013. Building a geometallurgical model in iron ores using a mineralogical approach with liberation data, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013 , pp 317-324 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 29, 2013

By M Haest

This study demonstrates the application of HyLogging™ technologies for mineralogical characterisation of different iron ore types throughout the Hamersley Province (Western Australia), including a channel iron deposit (Murchison Metals Ltd) and bedded iron deposits in the Brockman and Marra Mamba Iron Formations (BHP Billiton Ltd).Drill core from these deposits was analysed using CSIRO’s hyperspectral drill core logging systems (HyLogging systems), which are commercially available at the AMDEL and AMMTEC laboratories in Perth (Western Australia), through a leasing agreement. These HyLogging systems provide high resolution photographs at 0.1 mm pixel resolution as well as visible and infrared spectroscopic refl ectance data at 1 cm spatial resolution. The minerals identified include haematite, goethite and its subtypes (ie vitreous and ochreous goethite), AlOH-clays (kaolinite, Al-smectite and white mica), carbonates, gibbsite, chlorite, amphibole and hydrated silica as well as water content. The abundance and composition of these minerals was established from the spectral data and was validated against XRF analyses.The full potential of HyLogging systems in the iron ore industry is only starting to be unveiled, but some major benefits have already been demonstrated:• HyLogging systems can delineate different ore zones by mapping the vitreous and ochreous goethites. This has a potentially large impact in mine planning and operations, as hard, vitreous goethite and soft, powdery, ochreous goethite have different processing characteristics that can affect plant throughput if not carefully managed.• HyLogging mineralogy can also be used to support stratigraphic interpretations of the host, for example in subdividing the Dales Gorge 1 - 4 submembers of the Brockman Iron Formation.• HyLogging can have a potentially signifi cant impact on waste rock characterisation, as many of the waste materials can be identifi ed and quantifi ed with hyperspectral data (eg clay-type,• hydration state).• HyLogging can provide accurate three-dimensional (3D) mineralogy to iron ore companies that will empower them to improve future exploration and resource planning.• Application of high resolution photography to further improve ore deposit domaining is also to be considered.

Jul 11, 2011