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By R C. A Minnitt

This paper illustrates the use of variography and moving average plots as an aid to analysing variations in the process that can be used to direct the improvement efforts. The hydrometallurgical processes used in manganese metal production consist of sequential unit operations that include milling and reduction of manganese ores. Leaching of the reduced ore, is followed by solid-liquid separation, residue disposal, solution purification and electrowinning of manganese metal completes the process. The nearly 250 integrated process control loops rely on reports of pH, flow pressure, level, temperature and chemical analyses. Metallurgical accounting, reconciliation and process control is achieved through monitoring of the chemical and mass balances within the manganese reduction plant, requiring approximately 50 000 analyses of solids, powders and liquids each month. The largest numbers of samples are taken in the cell house. Changes and variations monitored by sample statistics ensure that the manganese products comply with predetermined specification limits. Optimising the information-value of the approximately 50 000 samples in the manganese plant is carried out in tandem with ongoing process optimisation. Variographic analysis of daily sampling data suggests that the cyclical behaviour evident in the moving average plots is only a reflection of random residual variability and not a reflection of true underlying variability related to cyclical phenomena. Low resolution in the variogram of daily sampling data masks the short-range variability that emerges when hourly data are analysed. Hourly samples collected over a 39-day period (giving 941 sample data), helped identify short-range cycles in the process. The relative distribution of variability for daily sample intervals, indicate that 57 per cent arises from V[0], 18 per cent from V[process] and 16 per cent from random residual variation. V[0] includes all the uncontrolled sampling error arising from a poor sampling protocol, the fundamental error (FE), the grouping and segregation errors (GSE), the delimitation error (DE), the extraction error (EE), etc. This confirms the suspicions regarding the suboptimality of the sampling protocol and the way it is implemented. The absence of long-term trends in the leach suggests that short-term variation (less than one day) dominates the process. While the control charts indicate that the overall processes are maintained above the lower specification limits and the target values, there is nevertheless a considerable amount of variability in the system that overhangs the processes and threatens to impact them negatively. Although the variability in the leach is above the prescribed limits, the volatility is a matter of concern because it seems to be uncontrolled. The comparison of the various sources of variability in data collected on an hourly basis suggests that the short-term random variability (V[0]) accounts for almost 50 per cent of the variability in the process. The main source of this variability is due to errors in the sampling protocol and is probably related to the size of the fundamental error (FE), the grouping and segregation errors (GSE), the delimitation error (DE), the extraction error (EE), etc. Remediation of FE and GSE will probably lead to a reduction in V[0], whereas V[process] could be mitigated by reducing the biases associated with DE and EE in particular.

Jan 1, 2008

By G F. Brent, R D. Hart, C Carr, F Felipe

In underground operations, where copper, gold and other metals are mined, the open stopes can be backfilled to stabilise surrounding workings. This fill may consist of tailings from the processing plant, usually mixed in slurry with a binder such as ordinary Portland cement (OPC). Extensive use is made of tailings in OPC-based paste fill, cemented hydraulic fill or cemented aggregate fill applications. A large underground operation such as the Mount Isa Copper Operations utilises over three million tonnes of backfill per annum. Geopolymers offer an alternative binder system with significant environmental advantages over OPC. Geopolymers are formed by polymerisation of aluminosilicate precursors in an alkali medium. They generally form products with superior strength characteristics as well as increased resistance to degradation, particularly under acidic conditions. Geopolymers have lower carbon dioxide emissions associated with their manufacture than OPC and offer further potential advantages, such as the use of less water and more waste materials. The application of geopolymers to weak material systems such as mine backfill has not been widely studied. The aims of this investigation were to assess a range of Australian mine process wastes for suitability as feedstocks in fill applications and to construct a range of these cemented minefills using a geopolymer binder. The physicochemical characteristics of each of the wastes are discussed as well as how they ultimately contribute to the geopolymer cement through direct replacement of OPC. Results from various tests on the candidate geopolymer fill formulations are presented and the potential of such fill formulations to replace OPC in mine backfilling operations is highlighted. The significant potential contribution to reducing greenhouse gas emissions from the use of geopolymer-based mine backfill across the industry is noted. Conversion of a single mine, such as the Mount Isa Copper Operations, is shown to match the reductions in greenhouse gas emissions due to the current total installed photovoltaic electricity generation capacity of Australia. A similar examination of wastes available to a gold mine could potentially yield new binders for use in established or new fill systems.

Jan 1, 2007

Your Excellency, on behalf of the Council of the Australasian Institute of Mining and Metallurgy, and, indeed, on behalf of everyone present, I extend to you a welcome, and our thanks for your gracious acceptance of the invitation to be here to-day and, later on, to present Honorary Membership Certificates. I also welcome the several official representatives of our Allies, of Great Britain and our sister Dominions.To Messrs. E. C. Driffield and E. J. Rigby, two of the original Foundation Members, who are with us to-day, I extend greetings.The present occasion is opportune to express, on behalf of a representative body of professional men, deep appreciation of the sacrifice which His Majesty the King has made, and will continue to make, by appointing His Royal Highness the Duke of Gloucester as Governor General of Australia and, therefore, His Majesty's senior personal representative in this country.I suppose, that as the primary reason for our assembly to-day is to celebrate the Fiftieth Year of the Institute's existence, I should properly on this occasion, give an account of its history and development. However, as this subject was ably covered by Mr. L. V. Waterhouse, in his Presidential Address in 1938, I trust I may be excused for selecting some other subject. I shall, therefore, exercise my privilege as President and give you a short history of the Mining and Metallurgical Industry of this country with special reference to its effect on the development of the Commonwealth and on the national economy. I apologize in advance for any statistics which I inflict upon you; some of these will be three or four years out of date, because of censorship restrictions. I shall as far as possible refer firstly to the industry prior to and including 1893, the Institute's foundation year, and then to subsequent development.Australia, is pre-eminently a pastoral and agricultural country and it leads the world in the production of wool. Nevertheless, it has an international reputation as a producer of gold and various metals and of minetal products.The development of gold mining in the decade 1840-50 was an epoch-making event in Australia's history, because, to quote one writer's apt phrase, "it precipitated Australia into nationhood." It was certainly responsible for a rapid increase in population. Thus, during the period 1841-1861 the population of Australia increased fourfold, from 221,000 to 1,170,000.The effect of the discovery of gold in Western Australia was even more striking. In 1890 the population of that State was 49,000 and in 1900 it was 180,000.Statistics in respect of gold are reasonably complete, even for the years prior to Federation, and it is interesting to note that the gold declared as...

Jan 1, 1944

The development of a noise attenuated compressed air driven fan is described. The fan, which employs the jet reaction principle, possesses blade extension pieces which penetrate into an acoustically treated annular chamber. The dominant noise source, namely the air jets, is thereby partially suppressed. In addition, the increased moment arm of the jets leads to an improved propulsion effect which contributes to the improved aerodynamic performance of the unit.A typical measure of the improvement of this type of auxiliary mine ventilation unit is a 4 per cent increase in efficiency and a 10 dB (A) drop in sound level for a fan duty of 0·5 kPa and 1600 litre/s. This degree ofattenuation corresponds to at least halving the loudness level, a subjective noise measure.

Jan 1, 1973

By Matters C. W

THE following paper embodies the present practice and the results of past experience in the survey departments of two of the leading Broken Hill mines, the Central (Sulphide Corporation Ltd.) and the Broken Hill South S. M. Co. N. L.The authors intend to limit the scope of this paper to a consideration of office methods, as much has recently appeared in technical literature concerning field work, both surface and underground. Special reference may here be made to a valuable paper on 'Mine Surveying' by H W Gartrell, in Vol XIII of Transactions, in which the author gives considerable attention to field work. Moreover, much of the office work described in current literature is American, and sometimes not suited to local conditions, being ·often exceedingly elaborate and demanding a large staff of assistants. It is believed that the methods of recording information described in this paper are sufficiently simple and flexible to be adapted to most Australian mines. Brief acknowledgement must be made to the work done by Americans, who have raised mine surveying to the position of a separate profession, instead of being merely an unimportant branch of land surveying.

Jan 1, 1912

Notwithstanding full concurrence with the dictum of a famous scientist that "definitions are the most accursed of all things on the face of the earth," in view of the considerable confusion which exists in jigging nomenclature, it is considered advisable to commence this paper with the following explanations of the terms which will be used throughout the text.Jig Bed. The whole layer of material lying on top of the jig screen.Ragging. The layer of denser material lying immediately above the jig screen, which is too coarse to pass through this screen and is confined horizontally by the cells of the top grid.Ore Column. The layer of ore pulp between the ragging and the top-water.Top Water. The water, carrying fine material in suspension, which flOiWS over the surface of the jig bed.Hutch Water. The water added to the jig below the screen. (Except for the water discharged with the hutch concentrate, the "hutch-water" eventually becomes "top-water.")Feed Water. The water in the ore pulp fed to the jig.(This water becomes part of the "top-water.")Pulsion. The period of the jigging cycle during which the water is moving upwards relative to the particles in the jig bed.

Jan 1, 1937

Plant for the production of sulphuric acid from pyrites flotation concentrates was commissioned at Cockle Creek during 1956, to meet increasing demands for commercial acid and superphosphate. Pyrite was chosen as raw material because of the uncertain supplyposition of imported brimstone and the desirability of utilising domestic sulphur.Desulphurisation of the pyrite is performed by two 40-ton per day roasters of the Turbulent Layer type operated under licence from the Badische Analin and Soda Fabrik (B.A.S.F.) organisation. These units are the first of their kind commissioned in the southernhemisphere. Pyrite is fed to the roasters in the as-received un-dried condition. Waste heat steam production is coupled with electricity generation within the plant. Sulphur dioxide is produced at comparatively high strengths and cleaned by conventional cyclone and hot electro-filter equipment.The acid unit has a capacity of 100 mono tons of sulphuric acid per day and includes cooling and wash towers, mist precipitators, a single stage drying tower, 4-pass oxidation section and absorption system.INTRODUCTIONSulphuric acid has been manufactured at Cockle Creek Works since 1913, when the first chamber nitration plant was commissioned. The raw material was brimstone roasted in Herreschoff furnaces. Since that time three additional chamber units have been constructed and have produced acid from brimstone, zinc concentrates, pyrites and -spent oxide, according to changing economic and supply factors.Three chamber units are still in operation. Contact processes have become increasingly important since the first Schroder-Grillo unit was commissioned in 1923. Six of these 5-ton per day units were operating in the mid-thirties, but have since been demolished. Two 15 ton Chemico hot gas contact units commenced operation in 1937 and 1938, and although modified, are still in service.The increasing demand over recent years for sulphuric...

Jan 1, 1957

A computerised cataloguing system for geological specimens is described. The catalogue is designed for use with a compactus-type storage system. The information stored in the catalogue for each specimen includes the type of specimen, locality information in terms of standard ~ap sheets and descriptive location, geological age, stratIgraphy, and specimen descriptions. The catalogue can be interrogated at any level of detail on the basis of any combination of these specimen parameters.Other information stored for each specimen 'is the compactus address, collection date, reference information and the type of analyses performed on that specimen:Any mterrogatlon produces a listing of those specimens which satisfy the search criteria.

Jan 1, 1974

By Lyon R. J P

The quartz-cassiterite-wolfram veins at the Aberfoyle Tin Mine, north-eastern Tasmania, form a sheeted zone about 200 ft. wide and 1,600 ft. long in slightly contact metamorphosed shales, slates and greywackes, and are associated with a cupola of aplitic granite whose top is about 1,050 ft. below the present surface. Economic mineralization persists from the surface down to a vertical depth of 1,050 ft. to 1,100 ft., dying away in the vicinity of the cupola. Down to the 9-level there is a progressive increase in wolfram content of the veins, and a decline in cassiterite content, with increasing depth.The veins are banded or zoned, with a seivedge of muscovite on the wall. Cassiterite, wolfram and sphalerite occur inside the selvedges, projecting into a core of quartz of varying width. Other sulphides form the central part of some narrow veins, or occur as clots in the quartz. The general sequence of deposition of the ore minerals was: (1) cassiterite, wolfram; (2) arsenopyrite, pyrite, molybdenite; (3) pyrrhotite (in part); (4) blende-group minerals-chalcopyrite, sphalerite, stannite, pyrrhotite (in part)-as solid solutions; (5) galena, tetrahedrite, matildite, native bismuth, scheelite; (6) marcasite and secondary pyrite, magnetite and hematite. The sequence of deposition of the gangue minerals was: (1) fluorine-bearing minerals-muscovite topaz, apatite, triplite, fluorite-more or less contemporaneous with the cassiterite and wolfram;' (2) quartz-contemporaneous with the earlier sulphides; (3) carbonates--contemporaneous with the later sulphides. The stages overlapped somewhat.The composition of the sphalerite and heat treatment experiments with the solid solutions indicate that the blende-group sulphides were deposited at about 6000 C., and cooled rapidly, so that unmixing of the solid solutions was arrested. This accords with the likelihood that the country rock temperature was not above 2000 C. Annealing experiments at between 3500 C. and 6000 C. led to further precipitation from solid solution at the lower temperatures, and to significant segregation by solid diffusion within, a week, indicating that both deposition and cooling of the ore were rapid processes-completed in a matter of days. Since the mineralizing solutions must have lost some heat during...

Jan 1, 1957

Up to 19 chemical parameters were studied in flotation pulps in six Australian lead-zinc concentrators with the aim of obtaining a better understanding of the nature of, and changes in, the chemical environment. This paperdiscusses pH, redox potential, and oxygen concentrations, which were all measured continuously.Two plants operated at natural pH in slightly acid circuit and one at natural pH in alkaline circuit, and pH was stable at all these plants. In two plants varying amounts of cement fill were present in mill feed and pHwas variable. At the other plant pH was controlled with soda ash and lime.Redox potentials became more positive as the pulp passed through the plant. The minimum change was 20 mV and the maximum about 250 mV. Potentials tended to be variable at any point early in the circuit, but were more stable later on. In some plants reagent additions had no noticeable effect on redox potentials. However in the two plants operating in acid circuit the redox potential of .zinc rougher feed was markedly affected by changes in copper sulphate addition rate. Sodium sulphite additions had an effect at other plants.Oxygen concentrations in grinding circuits tended to be low (30 per cent of saturation) and very variable. Flotation was usually conducted in pulps at least 90 per cent saturated with oxygen. Addition of sodium sulphite had a marked effect on oxygen content in one plant, but less effect in two others.Statistically significant relationships were found in some plants between pH and redox potential, redox potential and oxygen saturation, and oxygen saturation and pH.Improved control of copper sulphate and sodium sulphite additions could result from applications of this work.

Jan 1, 1970

An Ammonia Leaching-Solvent Extraction-Electrowinning-Flotation Process for Copper Oxidised Ore Treatment

Sep 13, 2010

By B S. Utting, W J. Cowie

The alluvial gold industry of New Zealand is based on the placer deposits in Otago and on the West Coast. Production from these since discovery in the 1850s has been an estimated 480 t (15 Moz) of gold. Annual output has expanded continuously since 1980 and is expected to be over 2 t of gold for 1989. Following a historical review, the characteristics of typical operations, which use hydraulic excavators and mobile trommel units are discussed. Descriptions are then given of alluvial activities in Otago and on the West Coast.

Jan 1, 1990

By Ware AR, Doyle BJ, Hoogvliet H

The Ladolam deposit lies within the altered volcanic rocks of the caldera floor, part of which now forms Luise Harbour. It was discovered in 1982 in the course of a reconnaissance drainage sediment sampling programme. This was designed to follow up indications of surface hydrothermal activity noted by Government geologists during an earlier survey of the Tabar-Feni island chain. Diamond drilling began in September 1983 and by the end of 1989 a payable and proved mineable reserve containing 19 million ounces of gold had been established. Rock types and structures are masked at the surface by intense alteration and weathering. An extensive drilling programme has enabled the identification of these features and the relationships between them necessary for an understanding of the factors controlling gold mineralisation. It has also led to the recognition of two distinct phases of alteration. The first phase of porphyry-style potassic alteration was followed by violent caldera formation, producing extensive brecciation and veining. The second alteration phase partly over- printed the first phase and was an epithermal one, evidenced by argillic, advanced argillic and phyllic assemblages. During this event, a large volume of fluids circulated under the favourable structural conditions; these fluids included a sulphur- rich, neutral chloride brine believed to have transported the gold. Boiling and mixing of circulating fluids in the open breccias is thought to have resulted in deposition of the gold. There is evidence that this process is continuing at the present day.

Jan 1, 1991

By S M. Iveson, K P. Galvin, D Kumar

Dry separation of iron ore fines and other heavy minerals has previously been achieved using one of two main approaches. The first is an inclined table with an upward airflow via small holes to help form an autogenous dense medium. The second is based on fluidised beds comprising a dense medium formed by fine particles suspended in an upward flow of air. In either case, vibration can be introduced. This paper describes recent findings using a novel system referred to as the Sink-Hole Fluidiser, which utilises elements of both these two former approaches. This device consists of a conventional gas-fluidised bed of fine medium with a 1 mm aperture mesh located at the surface. This mesh contains relatively large holes that act as sink-holes. The fluidised media flows upwards through the sink-holes and then falls back into the fluidised bed via the fine apertures in the mesh. The particles being separated, which are much larger than the fine media, pass over these sink-holes, where they either sink or float. The sink-holes offer a more precise balance of forces, applied on a single particle basis, resulting in robust density separation.Experiments have been performed using 2.0–4.0 mm tracer particles of density varying from 2.4 to 4.8 relative densities (RD) separated in a 200 mm diameter Sink-Hole Fluidiser with a single 13 mm diameter centrally-located sink-hole. In this preliminary semi-batch work, it was found that the Sink-Hole Fluidiser was able to achieve sharp separations (Ep as low as 0.20). This work underpins the development of a new continuous steady-state Sink-Hole Fluidiser, applicable to the dry separation of iron ore fines.CITATION:Kumar, D, Iveson, S M and Galvin, K P, 2017. A novel sink-hole fluidisation method for dry separation of iron ore fines, in Proceedings Iron Ore 2017, pp 221–226 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By Blanchard R

In stopes of the 2000- and 2150-ft. levels in the North mine section of North Broken Hill Limited, whence a substantial proportion of the company's production is being drawn, and especially in stopes which involve the portion known as the Northern orebody, occurs it light-coloured friable porous material which represents average grade ore from which the lead and zinc minerals, and certain gangue constituents, have been largely or wholly removed by leaching. The 2000- and 2150-ft. levels lie, respectively, 1550 and 1700 ft. below extreme base of the pre-mine oxidized zone. Composition of the cellular product shows it to be supergene. The oxidation and leaching, therefore, must be assumed to have taken place since drainage of the affected areas was accomplished by mining operations.The matter is of more than passing interest, because the post-mine...

Jan 1, 1942

Hot briquetting is a reliable, fully developed industrial concept for the passivation of direct reduced iron produced with the various processes of direct reduction. During hot briquetting, the large specific surface area of direct reduced iron is drastically reduced, and therefore the well-known problems caused by reoxidation and overheating are avoided. Even the shipping instructions published by the International Maritime Organisation (IMO) confirm that Hot Briquetted Iron (HBI) can be handled and shipped without special precautions. From the mid-1970s until today, after extensive pilot testing of the technology, a number of industrial plants for the hot briquetting of direct reduced iron have gone into operation. Additional hot briquetting plants for already established but also for new direct reduction processes are tinder construction or in different stages of planning. This paper describes the characteristics of HBI and its current industrial application for various Direct Reduction Processes.

Jan 1, 1999

In a previous paper of this series (1) ,t it was shown that during the creep of single crystals of lead, deformation proceeded to some extent by means of slip on the octahedral plane. This was demonstrated by the formation of slip lines on the surface of the specimens. At first, a few broad bands appeared after a small amount of extension had taken place; then, as extension proceeded, more and finer lines made their appearance until the whole of the specimen surface was covered.The present paper deals with the process of deformation of the creep specimens as revealed by X-ray examination..By the use of this method, the changes taking place in the crystal structure can be observed.EXPERIMENTAL METHODThe method of preparation of the specimens, their size and the purity of the lead employed have been reported elsewhere (1). At frequent intervals, the specimens were dismantled from the test rack and X-ray back reflection photographs were taken. The specimens were so marked and set up on the X-ray machine that the same spot on the specimen surface was always examined.Copper radiation was employed, the tube voltage and current being 45 kV. and 25 m.a. respectively and the exposure time 2 hrs. The slit diameter was 1 mm.

Jan 1, 1941

In referring to two subjects of interest to the Members of this Australasian Institute of Mining Engineers, I would at the outset desire to express our gratification that to-day we are able to welcome as now united with ourselves, those members who until recently constituted the New Zealand Institute. It is hoped that the amalgamation so amicably arranged may be productive of the best results to all concerned, incorporated as this combination has been at the moment of the fulfilment of that greater political union, the Australian Commonwealth.Since last Annual Meeting held in Brisbane, we have come under the same roof as the Chamber of Mines of Victoria, and we entertain the hope that as that Chamber and this Institute possess so many interests in common in the encouragement and advancement of mining and metallurgical progress in these colonies, that much mutual benefit will ensue. There are many directions in which each body can assist the other, and I trust that a friendly co-operation will be maintained.It is gratifying to feel that in all the colonies a distinct movement is being made to increase the facilities for education in Mining and Metallurgy but if I may refer to our colony of Victoria in particular, we have to express the profound regret that in the means of education in the higher branches, we occupy an inferior position, and it is quite certain that we will continue to do so unless the Government is prepared to subordinate provincial considerations to the weightier.

Jan 1, 1901

By B Chi, A Mahanta, R A. M Maddever, O Dominguez

BHP Billiton, in collaboration with Sodern and CSIRO, has developed a downhole logging tool for measuring geochemistry in situ. The FastGradeTM 100 (alternatively, FG100), exploits pulsed fast and thermal neutron analysis (PFTNA) to analyse the rock. This method is based on the detection and measurement of characteristic gamma rays emitted from isotopes in the material that become briefly radioactive when they are bombarded with neutrons. The tool outputs raw spectra arising from three types of neutron interaction, namely, inelastic scattering, neutron capture and neutron activation, which occur in successive time-windows (Smith et al, 2015). The spectra contain peaks at specific energies that are characteristic of the different elements interacting with the neutrons, the gamma count of which is related to elemental concentration. BHP Billiton uses in-house data processing software to convert the measured spectra to elemental concentrations.Much work has been done to understand the tool response under a wide variety of environmental and operating conditions, including logging speed, borehole rugosity, the presence of cavities, water etc. Effort has also been directed at understanding and quantifying the current sources of error in our conventional assays due to sample collection, preparation, and laboratory instrumentation in order to use this information as a baseline to compare against the FastGradeTM 100 results.To date, the FastGradeTM 100 primary use has been as a verification tool (JORC, 2012). However, beyond this, it has considerable potential to improve productivity in both exploration and production environments due to its ability to provide geologists with assay results soon after a hole is drilled.This paper presents initial test work and tool performance, including accuracy and precision under various conditions. Results are illustrated by comparing tool measurements to assays from laboratory samples collected from both reverse circulation and diamond-drilled holes.CITATION:Chi, B, Maddever, R A M, Mahanta, A and Dominguez, O, 2017. Near real-time assay with downhole assay tool (FastGrade™ 100), in Proceedings Eighth World Conference on Sampling and Blending , pp 137–144 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By T Do, J Siliezar, M Larson

With the expansion of magnetite projects in Australia has come the opportunity to take advantage of newer technologies that were not necessarily available when the magnetite industries of North America and Europe were maturing. One of these technologies is the IsaMill, originally developed for the economic treatment of ultra-fine grind (UFG) duties of Mount Isa Mines. As understanding of the IsaMill has increased, so too has the ability to process coarser feeds while maintaining the same energy efficiency advantage and tight product size distribution that originally made the IsaMill so attractive. In the case of magnetite the hard non-elastic ceramic grinding media is ideally suited to the grinding duty when compared to steel grinding media. The centripetal separator and naturally steep product size distribution curve provide a mill discharge that maximises the critical concentrate grade. This paper analyses the effect of the IsaMill grinding technology on the full-scale Ernest Henry Mine (EHM) magnetite operation along with pilot and lab scale demonstrations of optimisation. Issues encountered and the solutions to maximise the mill throughput and quality are examined in an effort to promote better understanding across the industry. CITATION:Larson, M, Do, T and Siliezar, J, 2013. Enhancing magnetite returns - the benefits of IsaMilling, in Proceedings Iron Ore 2013 , pp 411-416 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013