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Smarter Gravity Separation Using the Kelsey Centrifugal Jig With relatively coarse grained and easy-to-process ore sources rapidly dwindling, smarter techniques are becoming more necessary for the continued success of mineral processing operations, while increasing environmental pressures also require more environmentally friendly solutions. Gravity concentration has long been employed to pre-concentrate minerals using water, reducing or eliminating the need for less environmentally friendly processing techniques such as flotation. Conventional gravity recovery devices however, operate in a 1 g environment with limited efficiency in the separation of fine particles of heavy and gangue minerals. More recently developed centrifugal concentrators operate in a multi-g environment and enable finer heavy minerals to be recovered, but also exhibit limited separation efficiency due to the separations being based on solid particle mass differentials. Further enhancement of gravity separation has been achieved using the Kelsey Centrifugal Jig (KCJ), which also operates in a multi-g environment, but separates minerals on the basis of specific gravity differentials, using 'ragging' media and a pulsation mechanism, which maximises the effect of differential particle accelerations. This enables the efficient separation/recovery of minerals down to a particle size of ~6 ¦m and/or separation of minerals with a low specific gravity differential. This paper presents details on the principals of operation of the KCJ, recent improvements in the technology and recent developments in modular KCJ plants, as well as some KCJ application areas, which offer smarter, environmentally friendly processing opportunities for the mineral processing industry.

Sep 13, 2010

By D Brett

"Mine waste storages including tailings dams and waste rock dumps represent arguably the biggest risk on a mine site from both physical and geochemical viewpoints, related firstly to structural stability and the consequences of failure and secondly from potential on-going seepage or run-off of acid and metalliferous drainage (AMD). The risks are most likely to increase during operations and continue through the closure and post-closure phases, with the waste storages likely to be the most difficult features to resolve in the mine closure process. Contaminated water quality from tailings dams and waste rock dumps can require treatment "in perpetuity" at a cost of hundreds of millions of dollars. The problem is increasing with ever larger mine operations and waste generation volumes. This paper identifies leading practice methodologies in planning and operating mines and process plants to minimise the risks from tailings storages and how this might also affect waste rock management and even the design of mine excavations. These methodologies require a "big-picture" approach to develop an understanding of the overall issues and identify synergies between the different operational areas on a mine site that can reduce overall risk. With a conservative approach and realistic allowance for future costs it is possible to facilitate decisions at the mine planning stage that can reduce risk and save cost over the long term. This is in contrast to the common approach where each operational area is looking to minimise its own costs with a short-term view. Incorrect mine methodologies can be developed by allowing net present value (NPV) accounting methods to trivialise future closure issues.Methodologies discussed include: Integrated Waste Management - Significant structural improvements to tailings dams can be achieved if the structures can be incorporated into the waste rock dumps. Risk of AMD can also be reduced by utilising the tailings and waste rock effectively. This could go even further to consider the placement of wastes to limit mine void environmental issues; Process Optimisation - Water quality and the nature of potential tailings dam structures can be highly influenced by the geo-chemistry of the tailings. This can be modified by processing, where simple changes such as maintaining separate streams of geo-chemically different tailings rather than recombining them or by initiating further processing to remove problematic minerals such as sulphides; Enhancing Geophysical Properties - The geochemical performance of waste repositories can be greatly influenced by the geophysical properties of the stored materials, particularly the air-water characteristics, which are influenced by particle size, density and permeability. The geotechnical properties can be enhanced by strategic paddock dumping, blending and compaction.These methodologies are demonstrated by case histories.CITATION:Brett, D, 2013. Mine waste risk minimisation by integrated waste management and process optimisation, in Proceedings MetPlant 2013, pp 247-258 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 15, 2013

A general outline of the significant features in the quality and manufacture of the more common refractories is given. Where possible, linkage between quality development and control and service applicationhas been shown and explained. INTRODUCTIONThe refractory industry is no stranger to change. New processes and revision of old processes in other industries are the harbinger of new and revised products in refractories.Few of the changes are dramatic; generally they are evolutionary rather than revolutionary. New developments are additional to, and inclusive of, established practice.Therefore in this paper it is necessary to repeat much of what is already known in order to show the development taking place.FIRECLAY REFRACTORIESGeneral technology Fireclay refractories are the most common, the most varied and the most versatile of all refractories. Virtually any composition of silica and alumina up to the composition of kaolin is possible. For purposes of comparison they may be classified in the Continental fashion in accordance with chemical composition or in the American way according to "duty". That the two methods are equivalent is shown by an inspection of the alumina-silica diagram of Bbwen and Greig (1924). 'Fireclay refractories are composed of a glassy and a crystalline component derived from the chemical and physical nature of the raw materials used in their manufacture.

Jan 1, 1961

With a price slowly rising above US$35 per ounce gold became a mineral worthy of prospecting and mining endeavour in the early to mid 1970s. Fortune therefore appeared to smile onNew Zealand with its favourable geological environment for gold and past record of major gold production from both hard rock and placer deposits. This was a particularly welcome development as the post war years, including both the base metal exploration boom of 1967/1971 (which produced major nickel, iron and bauxite mines in Australia) and the earlier period of uranium exploration failed to produce any mines in New Zealand with the exception of the small Tui Mine and iron sand mining. Whilst hard rock mining now appears imminent it is 15 years further along the track since the 1967/1971 exploration boom and eight years since the upsurge in prospecting for gold in 1978. New Zealand still has no hard rock base or precious metal mining. This is not for want of proven or potential gold mining situations for these clearly exist at Waihi, Monowai Reef, Golden Cross, MacRaes Flat and elsewhere.

Jan 1, 1986

To finalise the arrangement and details of the headframe to be erected over the new No. 3 Shaft, the haulage and winding equipment requirements were first determined, then tentative designs were prepared to cover the needs of general shaft servicing work for men and materials, mullock and ore handling, and the probable requirements of a breaker station to be built adjacent to the headframe, which would provide for the crushing of the run-of-mine ore down to a size which would be suitable for feeding on to the concentrating mill.

Jan 1, 1957

The following observations on the mineral composition of the lead-zinc ores at Captain's Flat, New South Wales, are based upon the examination of a collection of specimens made during a brief visit to the mine in January, 1942, in conjunction with earlier studies of specimens and mill products, which have 'been the subject of various Mineragraphic Reports, Captain's Flat is about 35 miles south of Canberra, and is connected with the main line from Goulburn to Bombala by a branch line to Bungendore, 23 miles away from the mine.The geology of the mine has been described by Kenny and Mulholland2 and by Harper.3 The country consists of Silurian sediments, which have been invaded by a composite sill of quartz-felspar-porphyry. Both sediments and sill have been folded gently, the axial lines of the folds trending north and south. In the vicinity of the orebodies the folds are steeper, and thru,st faults are associated with the anticlines. The intense compression and shearing that accompanied the faulting has converted the adjacent porphyry to schist. The Captain's Flat orebodies occur along such a zone of shearing and faulting, on the eastern limb of a steep, north-pitching anticline. At their southern end the orebodies are enclosed in the slates underlying the porphyry, but the northerly pitch of the fold carries the slate to greater depth in the northern part of the mine, where the orebody lies beween schistose porphyry on the hanging wall and massive porphyry in the footwall.THE OREBODIESThe orebodies occur along a N.-S. strike length of 4,200 ft., and from the point of view of mining, fall into three sections: the Elliot's Section to the north, the Central Section, and the Keating's Section to the south. The Keating's Section is separated from the Central Section by 500-600 ft. of mineralised ground of so low a grade as' to be called barren, and is offset about 125 ft. to the 'east of the Central body by an oblique fault striking N.300E. Elliot's Section and the Central Section are connected by persistent veins and stringers of lead-zinc ore, but although these are...

Jan 1, 1943

The term slag has been used to define a wide variety of material including mine spoil and slag produced at steel plants. The present paper is concerned only with the non-metallic alumino-silicates developed simultaneously with iron in blast furnaces.The control of iron quality by slag has long been appreciated but here aspects of slag control based on concurrent iron production are indicated. Consideration is given to the basic composition of slags relative to the type of allotrope required. Up to a point, the plant conditions, under which a particular slag type is processed, have some effect, but these conditions only widen the range of a given allotrope.They do not convert one slag type into another. The nature of the slag types and experiments with additives to convert one slag type into another are discussed.The various uses for allotropes of blast furnace slag are considered.Their use in air cooled slag, foamed slag, slag wool, cements, soil stabilization, glass bottles, and building bricks and blocks, is explored in some detail.INTRODUCTIONWithin recent memory, blast furnace practice has been solely concerned with the production of iron. The slag make at this time had not reached embarrassing proportions. In Britain, unlike Germany, no legislation existed to prevent the growth of unsightly slag banks. Generally slag found limited use as fill and road material in the immediate plant vicinity. This is broadly the case in Australia today. In Europe and America, where the slag make is of the order of several million tons annually, the room problem and the cost of dumping slag has stimulated commercial and scientific research on the disposal problem. Currently, most iron plants in Europe can profitably dispose of at least 95 per cent of their slag make.

Jan 1, 1964

By N Coplin

Australian Coal Association Research Program (ACARP) project C25073 was proposed by industry stakeholders seeking a potential solution that improves underground air quality and reduces operational costs associated with technology used to control diesel particulate emissions in the underground coal mining environment.The need to protect workers from diesel particulate matter (DPM) has lead the underground coal mining industry to install disposable filter systems on their vehicles. While the disposable filters are efficient at removing significant amounts of DPM, the following major issues have arisen:- high cost of operations; disposable filters cost $A250–300 each and need to be changed at least once per shift resulting in an estimated cost of up to $A164 M/a, in filters alone, to the NSW underground coal mining industry- improper installation, damaged seals and lack of installing a new filter when the old filter is removed; workers are still being exposed to excessive amounts of DPM.The ACARP project successfully demonstrated significant DPM emissions reduction comparable to the incumbent disposable technology on a proof-of-concept wall-flow diesel particulate filter (DPF) system, as well as satisfactory system robustness when assessed using an industry representative test cycle representing operations of a load haul dump (LHD) vehicle typical of that used by the Australian underground coal industry. It was noted in testing that the technology increased modal NO2 formation, but was compliant over typical operational duty cycles.One of the key benefits with the use of a wall-flow DPF system is its tamper-proof design, mitigating the risk of operating unfiltered diesel plant in poorly ventilated areas. Elimination of the need for continual replacement of disposable filters provides significant operational savings estimated to be up to 80 per cent of the incumbent technology.In addition to the above, the project also delivered a number of significant contributions to the knowledgebase of the Australian and international coal industry with regard to the characterisation of operations and control of emissions.CITATION:Coplin, N, 2017. Wall-flow type diesel particulate filter system to replace existing wet element filter systems used in typical LHDs in underground coal operations, in Proceedings Australian Mine Vent Conference 2017, pp 119–128 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

By Delahant A. B, Dworski M

From the Saranac Laboratory for the Study of Tuberculosis of the Edward L., Trudeau Foundation, Saranac Lake, New York:We are assembled to honor the memory of our friend and colleague, Donald Cummings, one of the founders and a past president of the American Industrial Hygiene Association. I deem it an Unusual privilege to have been asked to give this first memorial lecture and hope that what shall have to say may be worthy of the occasion. It is fitting that we should discuss here the subject of Silicosis to which he devoted such a large part of his life and it is doubly fitting, I think, that I should report to you an extended series of investigations carried on by his associates at the Saranac Laboratory.The subject of silicosis may seem hackneyed to this audience which is so familiar with the tried and accepted methods of prevention and control.But in spite of our efforts, the condition is still with us and unfortunately is still being produced in many places. In industries that now maintain good control of dust, fresh cases are appearing on annual re-examination, whose major exposure date back to the days before the hazard was recognized.A few new employees, with apparently ineffective upper respiratory protection against inhaled dust, develop silicosis precociously in environments that are comparatively harmless to their fellows. In plants that have relaxed their vigilance under the urgency of war production schedules, conditions again prevail that will produce, disease in the future.Silicosis acquired new interest with the announcement by Denny, Robson and Irwin(1) in 1937 that it could be prevented by the inhalation of powdered metallic aluminium. It so happened that without knowledge of their work, we at the Saranac Laboratory had for some months been conducting similar experiments with one of the hydroxides of aluminium.Quite independently we discovered that hydrated alumina would also protect animals against quartz. Our approach to the problem had been empirical; we were trying to neutralize quartz particles by coating their surfaces with an insoluble material following the lead of Kettle who in 1932 had shown that this could be accomplished with iron. He neglected to describe his method and the chemist who prepared his coated...

Jan 1, 1945

Epithermal deposits have been defined as the lower temperature end of a spectrum of hydrothermal mineral deposits and are inferred to have formed near the EarthÆs surface. The preservation of an epithermal gold deposit in an Archaean craton is rather problematic, especially when such deposits form clusters or groups as reported for the Pilbara and Yilgarn cratons. For two of the better studied examples of epithermal gold deposits in these cratons, Becher and Wiluna, the evidence that they formed near the Earth surface is non-diagnostic, and the epithermal origin appears uncertain. Despite the simplicity of the original definition, there have been numerous errors in classifying epithermal gold deposits. It is suggested that these errors are primarily due to poor criteria defining the group as there is limited evidence of poor observational science being the cause. The criteria being used to recognise epithermal gold deposits include tectonic setting, ore element suite and quartz vein textures. None of these are diagnostic of epithermal deposits and their link back to the original low pressure-temperature definition of the class is tenuous. There has been definition creep over time as new observations on potential epithermal gold deposits become accommodated within a flexible definition. There is some urgency establishing and then using criteria to reliably identify epithermal deposits. Distinction of epithermal gold from weathered gold deposits is an important step. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By E Hollinger, J L. Mauk

Gold-silver mineralised veins at Favona, represent a new low-sulfidation epithermal vein discovery that occurs less than 1 km southeast of the world-class Waihi deposit. The Favona vein is hosted in Late Miocene andesitic lava flows and local dacitic tuffs that are intensely altered to quartz, adularia, chlorite, illite or interstratified illite-smectite (with ten to 70 per cent smectite) and pyrite. Adularia is widespread and envelops the veins, whereas chlorite and illite are mostly restricted to the footwall, and illite-smectite is confined to the hanging wall of the Favona vein. At shallow levels, kaolinite, cristobalite and rare alunite overprint the above minerals. A polymict hydrothermal breccia also occurs above and in the hanging wall of the Favona vein and contains clasts of altered andesite and various quartz vein fragments. Fluid inclusions in quartz veins sampled over a 300 m vertical interval have a homogenisation temperature range of 175¦ to 266¦C and dilute apparent salinities of 220¦C and grading into illite-smectite and local smectite which formed at 2. In contrast, late kaolinite, cristobalite and alunite formed from descending steam-heated acid-sulfate waters. Overall, the Favona and Waihi deposits are interpreted to have formed at similar levels in a single low relief hydrothermal system, with each deposit representing a distinct zone of fluid upflow.

Jan 1, 2002

How to Evaluate Crushed Rocks for Concrete Production

Sep 13, 2010

I report results of over 850 microprobe analyses of sulfides, sulfosalts and electrum from the Favona adularia-sericite epithermal deposit of the Waihi district in the southern Hauraki Goldfield of New Zealand. Pyrite and marcasite from altered wall rocks that enclose the veins are stoichiometric, with compositions of FeS2, and no significant trace elements. In contrast, pyrite in veins commonly contains appreciable As (up to 3.2 wt per cent), and locally contains several tenths of a percent of Cu, Zn, Co, Ag and Sb. Vein pyrite may contain up to 0.22 per cent Au, but Au contents do not show a positive correlation with As. Limited electrum data indicate that it ranges from Ag0.47 Au0.53 to Ag0.54Au0.41Cu0.01Zn0.04. Chalcopyrite is stoichiometric CuFeS2, and most galena is PbS, but some galena contains up to 4.4 wt per cent Se, which substitutes for S in its lattice. The galena is not argentiferous; the highest Ag content is 0.45 wt per cent Ag. Sphalerite averages 4 mol per cent FeS, but ranges up to 15 mol per cent. Tetrahedrites [(Cu,Ag)10(Zn,Fe)2(As,Sb)4S13] show variable substitution, but most are Cu- Zn- and Sb-rich. Veins also contain aguilarite (Ag4SeS), stromeyerite (CuAgS), naumannite (Ag2Se), and mckinstryite [(Ag,Cu)2S].

Jan 1, 2004

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

By Goldney L. H

The authors review the literature and discuss the application of methods to the design of thickeners for ilocculated metallurgical pulps. The use and evaluation of flocculents is described. Experimental data show that design based upon laboratory settlingdata is acceptable. The economic aspect of design is also discussed.INTRODUCTIONFor many years there has been little change in the methods for the design of thickener installations. While modifications have been made in the method of applying the data all methods have been based on the observee settling rate of the solids. The development of a theoretical approach based on physical data would involve so many variables which affect the settling rate that the more practical approach of direct observation seems unlikely to be replaced as the basis of design.The advent of synthetic fiocculents has introduced a modification in operation which affects design and should be considered. The authors review the subject and attempt to bring it up to date with present day procedure. Until recently the original work of Coe and Clevenger (1916) remained the basis of thickener design. They described their observation of the different zones encountered in settling, namely clarification, feed, transition, and compression or thickening- zones. The solids pass through the transition zone in settling from feed density to some higher density where settling ceases and ·some compression or compaction effect controls. the density obtained. The point at which the settling zone ceases to exist is known as the critical point.

Jan 1, 1959

By Parker A. J, Giles D. E

Solutions of copper(II) sulphate in acidified aqueous acetonitrile leach copper from copper-lead matte derived from the drossing of lead with sulphur to produce solutions of copper(I) sulphate. The reactivity of the matte constituents towards copper(II) sulphate is Cu2S> PbS > CuS > > Pb. According to the leach conditions, part or ,all of the copper may be leached 'leaving a residue of CuS/PbS, or S/CuS/PbS04, or S/PbS04, to be recycled to the lead smelter. Complete extraction of the copper requires leaching with oxygen which occurs under mild conditions in the presence of acetonitrile and sulphuric acid in water. Copper is selectively recovered as a pure product by electrochemical or thermal disproportionation of copper(I) sulphate solutions. A notional process is proposed.

Jan 1, 1979

By M Zhu, G Tranell, J You, K Tang, X Ma

The thermal conductivity of slag is critical for the efficiency of high temperature metallurgical processes such as the smelting reduction of ferroalloys, the ladle refining and the continuous casting mold flux in steelmaking. Experimental determination of slag’s thermal conductivity is fraught with challenges, as seen in yielding data for the SiO2-Al2O3-CaO system that are often inconsistent and widely dispersed. In molten slags of this system, thermal transport occurs via phonons within the network structure. To quantitatively describe thermal conductivity based on the microstructure, hightemperature Raman spectroscopy was employed to measure the silicate tetrahedra Qi (i = 0, 1, 2, 3), with Q4 species inferred from mass balance. This study also integrated molecular dynamics simulations to provide a fundamental understanding of the microstructure units distributions. Machine learning algorithms, especially deep neural networks, were applied to establish the relationship between slag composition and the configuration of tetrahedra. The thermal conductivities were then connected with silicate tetrahedra Qi using an Arrhenius-type formalism. This study sets the stage for extending our findings to more complex, multicomponent slags, enhancing their practical application in industrial processes.

Aug 21, 2024

By D Lichti

This paper presents recent advancements in the MillMapper software technology, developed and used for thickness gauging of liners of cylindrical grinding mills used for mineral comminution. MillMapper uses calibrated laser scanner data captured inside a mill to determine thickness at several million points on all liner surfaces with millimetre accuracy. The paper is structured as follows. First, a review of the technology and its numerous advantages over existing techniques and the value it adds to operations are presented. These are followed by discussion of recently-implemented innovations, including improved visualisation and inspection tools, automatic ball charge volume measurement and automatic mill liner volume/weight measurement. Results from its application at several sites in Australia are presented throughout.

Jan 1, 2007

By Noller B. N, McGill R. A

The Alligator Rivers Region has been the scene of one of Australia's most intensive environmental monitoring efforts since the current generation of uranium mining was mooted in the 1970s. Prior to mining, the local environment and the nature of potential impacts were not well known. The initial monitoring programs therefore included large baseline characterisation and research components. After some 15 years, water, soil and sediment monitoring programs have been reduced to a fraction of their early size, as the mining and natural systems became better known and characterised, and the actual nature of the environmental impacts were established. Modem techniques allow much more rapid and thorough identification of chemical species and elements of concern, allowing much more focused monitoring programs to be designed. In the 1980s data collection was emphasised at the expense of interpretation, and monitoring programs were maintained at much higher levels than were in fact required. It is now clear that investigations are important and should be distinguished from monitoring programs, and that the timely interpretation of investigations and implementation of recommendations can greatly reduce the effort and expense that can be involved in a monitoring program. Monitoring programs based on a sound understanding of potential environmental impact may then be efficient and cost-effective, yet provide sufficient information to assess the environmental impact of mining, guide further environmental protection measures when problems are detected, and demonstrate compliance with regulatory requirements.

Jan 1, 1994

By Grace NC, Lightfoot BW

Small scale trials of the smelting of a copper concentrate in the Sirosmelt submerged lance reactor are described. Pellets of concentrate were dropped into the reactor while injecting air-rich mixtures of oil and air through a lance into a bath of matte overlain by slag. This produced a discardable slag and a matte which was converted in sequential stages in the same reactor to white metal and blister copper. Difficulties were encountered in determining the end points of the converting stages but control techniques were developed to allow successful operations producing blister copper. Deportments of minor constituents of the concentrate to slag, matte,metal and fume for the three stages are reported and possible applications are Discussed.

Jan 1, 1980