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By T Weldon

In the last 15 years, it has become increasingly popular to win gold and silver from carbon strip solutions with electrolytic æsludgeÆ cells. The precious metal sludges produced in the cells are washed to the cell bottom and pumped into filters. Most new operations are specifying sludging cells, and many older operations are being retrofitted with up-to-date electrolytic sludge cells and filters. The new sludging cells are generally more energy efficient than older cells, but more importantly, the cell operations to remove product are much less labour intensive, cleaner, and the operator need not have physical contact with the electrolytically produced metal. A case study of a major North American gold producer (50 000 kg/yr) that removed old style stainless steel wool cathode cells and installed new sludging cells and sludge filters is presented. The effect of various impurities is discussed.

Jan 1, 2005

According to the temporal and spatial distribution of regional metallogenesis, the Pacific Rim can be divided into four global metallogenetic systems. The Asia-Australia W-Sn metallogenetic belt is the typical representative of intracontinen- tal metallogenetic systems. This belt resulted from Mesozoic and partly pre-Mesozoic tectonic magmatism, mainly re- lated to S-type granite of crustal source, that was generated by collisional orogeny combined with oceanic subduction in intracontinental and continental margin settings. Based on the concept of metallogenetic series, there is a group of min- eralised ore types showing a definite spatial and temporal distribution from endogenetic to exogenetic. These metalloge- netic series are widely distributed in the Asia-Australia W-Sn metallogenetic belt, and are well developed in Southeast China. Five metallogenetic series and two petro-minerogenesis evolution models have been established according to their tectonic settings, various types of granitoids and metallogenetic evolution.

Jan 1, 1995

By White A, Price G

The main assets of a mining company are its orebodies; the second are the people who find and use them.The graphs in Figure 1 were derived from a paper by Rob Macdonald of Rothschild Australia presented to The AusIMM Centenary Conference in Adelaide earlier this year. They show that the value of the industry on the Australian Stock Exchange halved over the past decade, despite the re-investment of capital equivalent to its full market capitalisation. Why is this so? The average dividend yields for the ASX Mining Index was never above five per cent during that period and barely averaged 2.5 per cent. Why then is $Ai million capital re-investment per employee since 1960 not enough to generate a rate of return to investors better than lousy bank interest? Do the investing public no longer regard our industry's assets to be world class?

Jan 1, 1993

By Nickelsen J, Theisen KG, Hansen PH

The use of stationary calciners in the processing of aluminium hydroxide has emphas- ized the importance of Bayer hydrate properties with respect to particle breakdown during calcination and subsequent treatment. Test results from calcination of several Bayer hydrates to sandy alumina in the FLS Gas Suspension Calciner (GSC) were obtained in a 250 kg/h pilot plant unit. Particle breakdown during calcination was influenced by content of solid sodium oxalate, trapped in the hydrate particles and operating gas velocities. Owing to the design and operational principles of the GSC it is possible to reduce particle breakdown to at least the same as what is found in long rotary kilns. Other major advantages reviewed are obtained through simplifications in plant design and operation, pointing to low specific power and heat consumption, and generally low production costs, thereby providing an attractive alternative to fluid-bed calciners.

Jan 1, 1981

By E Forbes, G V. Franks

"This study investigates the dual function of a temperature responsive anionic co-polymer of poly (N-isopropyl acrylamide) (PNIPAM) as a selective flocculant/flotation collector. PNIPAM is used for separating hematite from 50:50 mixtures of hematite and quartz, at a variety of particle sizes. The performance of PNIPAM in this system is compared to that of conventional flotation collectors: sodium oleate and sodium dodecyl sulfate. The results of the study demonstrate that anionic PNIPAM used at 50¦C (above the lower critical solution temperature (LCST)) is the most effective flotation collector for hematite particles in the size range between 10 and 20 ¦m. This is attributed to the increased probability of both particle/bubble collision and particle/bubble attachment through the formation of hydrophobic hematite aggregates. Anionic PNIPAM used at 50¦C also produced the highest hematite recoveries for very fine hematite particles (circa 1 ¦m). However this recovery was completely unselective. This lack of selectivity is partially attributed to the activation of quartz particles by PNIPAM, but is thought to mainly occur as a result of entrapment of quartz particles within the matrix of hematite aggregates.CITATION:Forbes, E and Franks, G V, 2013. Selective separation of hematite from quartz by flotation using a temperature responsive polymer, in Proceedings Iron Ore 2013, pp 381-390 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Aug 12, 2013

By B P. Banerjee, D Patra, S Raval

Roof bolts are an essential component of roof support systems in underground mines. They are used to provide structural support to the roof of the mine and prevent it from collapsing. Therefore, it is imperative to perform regular assessments of these roof bolts to avert any hazards. Manual investigations of roof bolts are done by surveyors in underground mines, which is extremely timeconsuming and challenging due to the low-light conditions in underground mines accompanied by stringent mine access rules. To this end, automated recognition of roof bolts in 3D point cloud data obtained through laser scanning in underground mines serves as a potential solution to aid roof bolt monitoring. With the continuous advancements in laser scanning-based 3D data acquisition systems, the feasibility of making such surface estimations from 3D point cloud data has increased severalfold.

Sep 1, 2024

By M Ma, W J. Bruckard, C Gontijo, R Holmes

Vale is the largest iron ore producer in the world. Since the 1970s, Vale has been using reverse cationic flotation to remove siliceous impurities from its iron ores. Whilst this flotation process has operated effectively for many years, it suffers from the problems of high reagent costs and high metal loss.In 2010, CSIRO investigated the use of a reverse anionic flotation process for Vale iron ore. Batch laboratory flotation studies conducted on Vale samples showed significantly reduced reagent costs and improved recovery of iron. In this work, the flotation behaviour of the different impurities in the Vale iron ore sample using reverse cationic and reverse anionic flotation processes is compared. Detailed flotation responses are presented and the merits of the two different flotation schemes are discussed.CITATION:Ma, M, Bruckard, W J, Holmes, R and Gontijo, C, 2013. Impurity removal in the reverse flotation of iron ore, in Proceedings Iron Ore 2013 , pp 427-430 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

Particle Mechanics and the Design of Cyclone Tribochargers Triboelectric separation is a dry electrostatic technique that has shown promise in several particle processing applications. A tribocharger uses contact or friction to differentially charge particles of different materials, which are then separated by an electric field. The initial tribocharging process is poorly understood, with tribocharger design and operation largely a matter of trial and error. A better physical understanding of tribocharger operation would therefore be of immense value in the optimisation of triboelectric separation processes. A combination of charge measurements, trajectory modelling and high-speed video has been used to relate charging to particle mechanics in a cylindrical pneumatic cyclone, one of the most effective tribochargers for mineral separation applications, and the preliminary results are presented here. The consequences of these observations for cyclone tribocharger design and operation, and for tribocharger design in general, are discussed.  

Sep 13, 2010

Bauxite Resources Limited is grade drilling in its Western Australian Darling Range tenements to firm up resource definition and to develop mine plans. The Darling Range bauxite is generally in shallow deposits with minimum overburden. In the northern tenements, the ore is characterised by a higher silica layer which may extend from 0.5 to 1.5 m below, which high grade bauxite is found to a depth of four to 7 m. When grade drilling samples are taken, every 0.5 m and the recovered sample is weighed, logged and bagged. To eliminate splitting errors, the whole sample over the short interval is pulverised. Twinning holes variations are observed when using various drill rigs. Diamond core has been shown to give close to 100 per cent recovery and grades have been verified by digging bulk samples. As such, diamond core is used as the reference. It is intended to include sonic drilling as an alternative to diamond cores. This presentation details and attempts to explain the reasons for the observed variations in the various drilling methods used by Bauxite Resources Limited. This is an ABSTRACT ONLY no paper was prepared for this presentation.

Mar 1, 2010

By S Karosiya, A Sharma, M Jain, N N. Viswanathan, M M. Pande, D Kumar, S Kumar

Desulfurisation of steel during ladle refining is governed by both thermodynamics and kinetics. For effective desulfurisation, thermodynamically, a low partial pressure of oxygen at the steel-slag interface and highly basic slag which possess a large sulfide capacity are desired. Kinetically, the mass transfer coefficient of sulfur in the liquid steel and in the slag determines the rate of desulfurisation. A fast desulfurisation rate is achieved by maintaining sufficiently strong argon stirring of the melt. In the present work, sulfur mass balance for steel and slag was performed after the desulfurisation treatment for several industrial heats. The decrease in the sulfur quantity of the liquid steel was more than the increase in the sulfur quantity of the slag. The discrepancy in the sulfur mass balance suggests that the sulfur could be transferred to: (a) the gas (via slag) phase; or to (b) the refractory (crucible) phase. The preliminary investigation of the refractory samples taken at slag-refractory and steel-refractory interface showed no interaction of sulfur with the refractory. Therefore, the possibility of sulfur transfer to the gas phase was verified by carrying out melting experiments of sulfur containing slag in an argon/air atmosphere. Sulfur containing slag was initially melted in an MgO-C crucible under an argon atmosphere followed by creating the air atmosphere just above the melt. Careful sampling and analysis from the cold spots of the crucible, much above the melt surface, revealed formation of a fibrous structure. Scanning electron microscopy energy dispersive X-ray spectroscopy (SEM-EDS) analysis of these fibrous deposits confirmed the presence of oxides and sulfides. Oxidation of sulfur containing slag under air atmosphere was also performed using a thermogravimetric analysis (TGA) set-up. It showed a constant sulfur loss in the range of 1300– 1500°C. Thermodynamic calculations carried out using FactSage™ ver 8.3 for these experimental conditions are in good agreement with the observed results.

Aug 21, 2024

Most mining dredges are adapted from canal/harbour dredges. Their automation and control systems are generally not designed for integrated mining operations. Consequently they have a number of limitations. This paper describes a new dredge control concept which paves the way for improved efficiency and increased production.

Jan 1, 2001

By P Gardner

The Kanowna Belle gold mine in Western Australia has reached a depth of 1000 m on the way to 1300 m. A feasibility study undertaken in 2006 identified the mining of E-Block as both technically and commercially feasible. One of the major risks identified in the study was the ventilation capacity, as the existing primary ventilation system would not support the production schedule for mining and a major system upgrade would be required. Failure to provide the necessary airflow would put the project at risk. A review of the airflow requirements and infrastructure options detailed in the feasibility study was undertaken to ensure that the assumptions and design were optimised. This review recommended a minimum airflow of 206 m3/s, but by acknowledging the necessary constraints imposed by mining at depth and re-engineering the mine layout to optimise the primary ventilation circuit, this requirement was reduced to 160 m3/s. This represents a 22 per cent reduction in airflow and a reduction in capital cost that will see mining at depth become economically feasible at Kanowna Belle. This paper discusses the processes that led to a redesign of the mining layout and highlights the importance of including the ventilation network in the optimisation process.

Jan 1, 2008

By Kendall W. T C

This paper provides a brief overview of the history of the Chaffers Dewatering Project which was successfully commissioned in August 1993. Until the end of 1992 the `Superpit' and the deep mines of the Golden Mile had all been dewatered by a staged pumping system from the 28 level in the Lake View Shaft, which was removed at that time when the Lake View Mine was absorbed into the Superpit. Feasibility analysis had indicated that adaptation of oil industry technology offered the greatest potential for a low cost solution to the problem of dewatering the open pit and deep mines. A KCGM engineer and one of the authors visited the Jackson oilfields to look at the deep well pumping technology in use there in early-1991. In the final analysis a new dewatering station was established in the 23 level crushing station of the Chaffers Shaft using conventional plunger pumps, but the rising main was screwed 178 mm OD (7 inch) casing the suspended from the surface to a depth of 686 metres, and was installed using oilfield personnel and methods. Only the second installation of its kind in Australia, the project achieved the dewatering objective at about half of the capital cost of the more conventional approach and at lower operating costs as well.

Jan 1, 1995

By B Yang, L Wang, C Y. Ng

Flotation process intensification is often achieved through changing chemical reagent scheme or flotation machine or both, which likely brings a hefty burden to the flotation plants in terms of capital or operating expenditure. A novel approach to flotation process intensification is the use of acoustic sound, which has been demonstrated to be effective in improving the flotation of various mineral systems with different type of flotation cells. This approach was based on the dynamic stabilisation effect of acoustic sound on the flotation froth. The present work aims to understand the influence of various experimental conditions on the effectiveness of the approach. First, the effects of sound frequency and amplitude were studied with column flotation of silica particles. Results showed that the flotation performance was improved only within a certain range of frequencies and above certain amplitude. The study was then extended to the mechanical flotation of quartz particles with various size ranges and at two solids concentrations. With sound, the recoveries of different size fractions within the range of 20–212 μm were all increased. In particular, the recovery of 150–212 µm particles was increased from 0 per cent to approximately 25 per cent, demonstrating the potential for extending the upper limit of particle size in flotation by using acoustic sound. Furthermore, mechanical flotation of chalcopyrite particles at various collector dosages (50–150 g/t) was carried out with and without sound. Results showed that the increment of the final flotation recovery was increased with sound at different collector dosages. Overall, acoustic sound has the potential to be used as an effective and versatile method for flotation process intensification.

Aug 24, 2022

By J Williamson, M Griessmann

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Watershed tungsten deposit is located in the Hodgkinson Province of north Queensland, Australia. The deposit is hosted by Siluro-Devonian flysch-type meta-sediments of the Hodgkinson Formation, which were subjected to four major deformation events. Mineralisation has occurred syn- to post-D4 and is related to the intrusion of S-type granitoids of the Permian Whypalla Supersuite.Watershed is located within a regional NW–SE-striking melange zone composed of brecciated and intermixed arenites and shales. The major NW–SE-striking Tullah fault zone is situated in close proximity to the east of the deposit.The Watershed deposit occurs within a tightly folded upright anticline with NW-plunging fold axis. The anticline contains a major package of coarse-grained to conglomeratic arenite, which harbours the Watershed mineralisation. Several alteration styles occur within the arenites, of which Fe-poor calc-silicate alteration dominated by clinozoisite/epidote is the most significant. Less widespread but locally important alteration styles comprise garnet-dominated calc-silicate alteration, albitisation and sericitisation. The arenites are enveloped by unmineralised carbonaceous shales and shale breccias.Tungsten mineralisation occurs solely as molybdenum-poor scheelite and can be found as three styles: disseminated mineralisation in calc-silicate altered arenites, vein-style mineralisation with quartz-albite-scheelite veins and minor but high-grade mineralisation in albitised felsic dykes.Contact metamorphic rocks and geophysical data indicate the proximity of an underlying granitic body. It is believed that this granitic body was the main driver of the hydrothermal system generating the Watershed deposit. An early mineralisation stage caused the selective calc-silicate alteration of the arenites, while a second stage caused the vein-style high-grade mineralisation. The folded shales enveloping the arenites worked as an effective barrier that kept the mineralising fluids in a confined rock volume.The scheelite mineralisation at Watershed is open to depth, with a granite-hosted porphyry or greisen-style mineralisation anticipated below the current resource.CITATION:Griessmann, M and Williamson, J, 2015. The calc-silicate-hosted Watershed tungsten deposit, far north Queensland, Australia , in Proceedings PACRIM 2015 Congress, pp 545–550 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By L MacDonald, D Molver, D Pepper

Increasing contamination/impurity levels (including arsenic, antimony, mercury etc.) of concentrates is an issue of global commercial and health / environmental significance. With increasing environmental pressures at smelters, penalties for contaminants in concentrates continue to rise, accompanied by lower reject limits. There is a strong incentive for miners to investigate alternative means to remove contaminants in order to increase the value of complex ores and concentrates. This paper discusses the global problem of contamination in complex ores and concentrates, how the Toowong Process technology is a potential solution to this problem, and the opportunities this technology brings to the business of dealing with deleterious elements. CITATION: MacDonald, L, Molver, D and Pepper, D, 2018. The Toowong process for treatment of complex ores, in Proceedings Complex Orebodies Conference 2018, pp 119–121 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

By D Brown, K Markovic

The world is becoming an increasingly complex environment to operate within. Adoption and evolution of technology is occurring at a rapid pace and operating spaces are growing in interconnectedness and interdependency. In mining this is evidenced by the large-scale adoption of autonomous machinery, intelligent systems, Internet of Things (IoT) devices, and robotics to realise benefits in optimisation, productivity, and safety. To enable continual delivery and growth in operational performance, and to realise the aforementioned benefits, a new approach for managing mining and metals is required (Mining Review Africa, 2023). This means that an already talent constrained workforce must learn to manage the complexity inherent, evolving, and growing in the environment (Abenov et al, 2023). A key skill that needs to be further developed and deployed to combat these challenges and to enable robust problem solving is that of systems thinking, which is already practiced in pockets within the mining industry. Experience and learning can be leveraged from other industries and their application of systems thinking to ensure that focus is maintained on areas where the benefits from which will be optimised. With targeted application, a workforce capable of effective systems thinking can be the catalyst to optimisation across mining organisations.

Sep 1, 2024

By C K. Suzuki, J A. Yanaguizawa, D M. F de Santana, L R. P Leite, A H. Shinohara

In the present work, the microstructure and mechanical properties of structural mortar from glass insulators were studied by X-ray fluorescence, X-ray diffraction, infrared spectroscopy, microhardness and compression testings. The investigated glass insulators were manufactured between the 1960 and 1990 years and had been used in 230 kV transmission lines. The results evidenced that the structural mortar of glass insulator was replaced from Portland to aluminous cement along the years. The crystalline phases of the mortar were identified and mechanical properties were correlated.

Jan 1, 2008

By F Gervilla, J Laukkanen

The Kevitsa Ni-Cu-PGE deposit in northern Finland contains disseminated Ni-Cu-Fe sulfides, and platinum-group minerals (PGM). The 2.05 Ga-old ultramafic-mafic, funnel-shaped intrusion is intruded into a volcanosedimentary sequence. The major ore minerals are pentlandite, hexagonal pyrrhotite and troilite, chalcopyrite, cubanite and magnetite. Pyrrhotite and pentlandite are replaced by pyrite, millerite and heazelwoodite near the surface. Nickeline, maucherite and gersdorffite are locally abundant. A pilot feed sample of 575 t of the main orebody at Kevitsa had average grades 0.45 per cent Cu, 0.36 per cent Ni, 1.85 per cent S, 0.33 g/t Pt, 0.34 g/t Pd and 0.19 g/t Au, with 0.06 per cent Ni contained in silicates. Higher PGE contents (2 - 27 ppm) occur in a vertical N-S bearing fault zone. The PGM (n = 6022) mapped in specimens of four drill holes, consist of sperrylite 34.7 vol per cent, braggite and cooperite 18.5 vol per cent, geversite 17.2 vol per cent, moncheite 14.7 vol per cent, merenskyite 6.7 vol per cent, stibiopalladinite 4.3 vol per cent, sobolevskite 1.9 vol per cent, kotulskite 0.7 vol per cent, michenerite 0.6 vol per cent, keithconnite 0.3 vol per cent, rustenburgite 0.1 vol per cent, melonite, froodite, laurite together 0.1 vol per cent and only a few grains of sudburyite, irarsite, vysotskite, erlichmanite, hongishiite, Pt-Cu-alloys, three undefined Pd and Pt bismuthinides and antimonides and a Pd-Cu-bearing Pt-Ni-Fe sulfide. Most of the PGM, 62 per cent, are enclosed in silicates, 29 per cent are intergrown with sulfides, nine per cent are within sulfides. A portion of the PGE occurs in solid solution in sulfides and arsenides. Ni flotation yielded smelter-grade concentrates averaging 12.2 per cent nickel. The average sulfide Ni recovery is 78.8 per cent and total Ni recovery is 65.3 per cent. The average Pt is 10 g/t at 55 per cent recovery, Pd 7.7 g/t at 38 per cent recovery and Au 1.6 g/t at ten per cent recovery. Cu concentrates averaged 28.6 per cent Cu with an average recovery of 78 per cent and further 11 per cent in the nickel concentrate. The copper concentrate contains 4 g/t Au at 24 per cent recovery. The average Fe to MgO ratio 17.9 is well above the targeted minimum of 4.5. The pilot results show that the previously used TETA (triethylene tetramine) can be avoided and good quality, smelter-grade concentrates can be produced from the Kevitsa ore at economical levels of recovery by conventional flotation methods.

Jan 1, 2008

By Urie R. W

Fluidized bed roasting of copper concentrates from Mt. Morgan, Mt. Lyell, Mt. Isa, and Peko was performed in a 3 ft 6 in diameter, slurry fed, pilot plant roaster operated under autogenous conditions to produce calcines with desirable leaching properties. A 12 in. diameter, externally heated roaster, provided with a dry feed system, was also used.An account is given of important factors which influence roaster behaviour and performance, and the effects of operating variables on calcine composition and leaching properties are described. Due to copper ferrite formation, a maximum of approximately 50 per cent of the copper in the calcines may be in the form of CuO before the copper leach efficiency falls significantly below lOO' per cent. Recovery of gold by cyanidation of leach residues was consistently high and independent of roasting conditions.INTRODUCTIONIn traditional practice copper is produced by pyrometallurgical techniques when the ,copper minerals in the ore or concentrate are predominantly sulphides, and by hydrometallurgy when the minerals are oxidized. Copper smelting is most suited to large scale operations, and for many years small to medium size mines with sulphide orebodies have been interested ill; alternative processes.Since hydrometallurgical plants (ie. leaching and electrowinning plants) are essentially unitized, they may be scaled down in output without much loss in efficiency or increase in processing cost, and many proposals have been made for the application of this type of process following roasting of the sulphides to render the copper soluble. However, until the advent of fluidized roasting, it was not possible to control the roasting operations sufficiently precisely to produce calcines consistently of the required leaching characteristics.

Jan 1, 1961