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By G M. Volkmann

Pipe umbrella systems have effectively been used as an additional support system in the working area in weak ground conditions during the last decades. Thus, a considerable number of applications accounts in urban tunnelling with shallow overburden. However, this support system is also successfully used when a tunnel alignment crosses fault zones, sediments, moraines or talus with overburdens from shallow to deep. The pipe umbrella support system itself is termed differently worldwide – synonyms are canopy tube umbrella method, umbrella arch method, or long fore-poling method.One main reason for the increase in application is that this support system closes cost-effectively the gap between reasonable, normal supported tunnels and tunnels supported with more expensive special techniques like horizontal jet-grouting or ground freezing. By using this system, many projects can be built more cost effective without decreasing the common level of safety.The pipe umbrella construction method is pretty young, so the knowledge about this system has been intensely researched in the last decade. This led to an enormous increase in understanding the interaction between support system and surrounding ground, the mode of action, and the important details for construction.Pipe umbrella support systems are applied in difficult ground conditions, so a special developed measurement arrangement was used to observe deformations ahead of the working face during tunnelling. The evaluation of collected data sets identifi ed that cased-drilling systems have clear advantages compared to predrilling systems during the installation process in weak ground conditions. This may become important depending on project requirements, so this difference must be considered in design as well as in the tender document specifications.

Mar 8, 2011

By P D. Erskine, A Hine

The current Queensland Government’s rehabilitation guidelines for post-mining landforms present a hierarchy of preferred outcomes for different areas within the mine site (see Figure 1). Within all areas, restoration of a ‘natural’ ecosystem is clearly prioritised as the preferred end land use, although it is not a mandatory practice. Beyond the official guidelines, there is also an implied preference for renaturalisation echoed in most environmental impact assessments and closure plans (Lamb, Erskine and Fletcher, 2015). In practice, however, ecosystem restoration does not extend to construction of a realistic topographic form, largely rejecting the ‘natural’ aesthetic implied by ecosystem restoration in favour of adopting a functional aesthetic in deference to standard engineering criteria.This presentation argues that the established disconnection between actual and implied landform aesthetics is indicative of a wider problem around end landform planning. It contends that such disconnects are the result of the impact of competing ‘ways of seeing’ (Bradley and Kearney, 2007) the same landscape, and reflect the struggle between, and inclusion of, these differing perspectives within the planning process itself. We propose that recognition of the complexity of landscape perceptions is key to improving post-mining landscape outcomes, and the misalignment between land use values and landscape aesthetics can be addressed by establishing an overarching framework for landscape preferences. As such, we outline the reality of stakeholder landscape preferences, and present a critical response to current planning practices within the life-of-mine (LOM).CITATION:Hine, A and Erskine, P, 2016. Recognising and integrating stakeholder landform expectations into life-of-mine planning, in Proceedings Life-of-Mine 2016 Conference, pp 154–157 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By E Ben-Dor, D Bakun-Mazor, Y Ben-Ari

Determining the mechanical properties of rocks is important for various civil engineering fields, including the mining of raw materials for aggregates used in the construction and paving industries. Traditionally, the mechanical properties of rocks are obtained through in situ and laboratory tests during geotechnical surveys. However, these time-consuming surveys involve many resources. In contrast, hyperspectral remote sensing methods make it possible to identify the mineralogical composition and crystallographic structure of the rock; properties that control the mechanical properties of the rocks. In this work, we characterise the mechanical properties of carbonate rocks by using a hyperspectral sensor in laboratory conditions. We collected about 150 cylindrical samples of carbonate rock, with a wide range of strength values from several rock outcrops in Israel. We used a point spectrometer in the range of 0.4–2.5 μm and a spectral image sensor in the range of 3.0–12.0 μm, scanning the samples to obtain the signature of their light reflections and spectral emissivity. We then measured the samples’ density, porosity, water absorption, and uniaxial compressive strength (UCS). We used sophisticated data mining to find statistical relationships between the hyperspectral signatures of the samples and their mechanical properties. We used this data to identify the most dominant wavelengths for predicting mechanical properties. We found that the density, porosity, and water absorption of carbonate rocks could be confidently predicted based on spectroscopy data, while the UCS of the rock could also be predicted, but less significantly. The results of the study pave the way for the development of measuring tools for the mechanical properties of rock, based on non-destructive tests of quarrying materials.

Nov 29, 2022

I began my interest in sample preparation when I joined the Institute of Nuclear Sciences in 1962. I worked in the fields of rock dating and stable isotope geochemistry. Preparing a sample could take several days and the analysis took another day or more, so great care was taken with each sample. In 1968 I changed to mineral exploration analysis and was surprised to find that there was much less care in how a sample was taken and prepared. Virtually every sample was processed in the same way. In the use of ring and puck mills, Australia and New Zealand were among the world leaders. It took another ten years before labs in North America changed over from disc mills. In 1975, my partner and I divided our business into two parts. He took the laboratory into his consulting laboratory business and I took the small business that we had started, making ring and puck mills. For the next six years I was RocklabsÆs only employee. In the 1980s and 1990s, sampling specialists like Francis Pitard and Dominique Francois-Bongarcon began to make a difference in the understanding of what constitutes good sampling and preparation practice. They and others took courses on the new concepts of Sampling Theory, as developed by Pierre Gy. The desire for better procedures lead to the development of new machines, including the big bowl pulverisers from Australia, jaw crushers that could crush finely like our Boyd Crusher, rotating dividers of new designs and flow-through ring and puck mills. Other machines did not fare so well, including rolls crushers, cone crushers and hammer mills.

Jan 1, 2008

The first difficulty encount.ered in preparing this paper was to find a definition of the word "special" as applied to steel. The first thought is "obviously any grade not mild steel" but this is an over-simplification, because the term "mild steel" covers a series of carbon ranges, each found from experience to be especially suited to the production of a particular rolled section.Even if the Australian structural mild steels are excluded it is found that no part of the plant here is independent of special steel.The face-man on Iron Monarch makes his bench safe by barring down with a 0.6% carbon steel bar. He bores a hole into the ironstone with a 0.75-0.8% carbon steel drill, driven by a jackhammer which is built of a variety of special steels. After it is shot down, the stone is lifted by an electric shovel, very few of whose steel components fall into the general category of structural grades of mild steel.Further special steels are met with in the truck into which the stone is loaded, the hauling electric locomotive, and the rails on which these .run. Even the permanent way uses more than one grade, e.g., the crossings experiencing heavy service have their frogs built with austenitic manganese steel inserts.Special steels play their part in the overhead crane which tips these trucks, and in the crushers into which they discharge, and so they can be followed right through the production line, and they are still there at the seaward end of the ship loading boom at the head of the WhyalIa ore jetty.

Jan 1, 1951

By Manlapig EV, Lawson F, Clarkson CJ

A low grade middling sample from Mount Isa, Australia, assaying 31.7 per cent zinc, 12.9 per cent lead and 14.5 per cent iron was leached under atmospheric pressure in sulphate and sulphate-chloride solutions with ferric ions as oxidants. About 96 per cent of the contained zinc was dissolved into a 0.5 M H2SO4 - 0.5 M Fe2(SO4)3 solution at 90¦C within three hours from a five per cent by weight slurry density mixture. The leaching process is very temperature-dependent, suggesting a surface chemical control. In the latter stage, the leaching rates levelled off and the leaching was most probably controlled by both surface chemical reaction and diffusion processes. The addition of chloride ions in the leach solution resulted in an increase in the leaching rate. About 95 per cent of the lead sulphide contained was converted to lead sulphate which precipitated and remained in the residue. Essentially no lead remained in solution and the low chloride concentration did not affect the precipitation of lead sulphate. Half of the iron orginally present remained in the residue as pyrite although essentially all the cadmium and 90 per cent of the copper initially present were dissolved. Some three per cent of sulphide sulphur was oxidised through to sulphate, about 67 per cent was converted to elemental sulphur which can be recovered by solvent extraction, the rest remained in the residue mainly as pyrite. Ferric sulphate and sulphate-chloride solutions can be used to effectively leach finely ground lead-zinc middlings and other bulk sulphide concentrates. A complete separation of zinc from lead and silver has been demonstrated.

Jan 1, 1993

By Y Peng, D J. Bradshaw, X Chen

At NewcrestÆs Telfer gold mine, a strategy of regrinding pyrite rougher flotation concentrates has been proposed to increase gold recovery and reduce cyanide consumption in the CIL circuit. The regrinding will be followed by an additional copper/gold flotation stage, where copper minerals need to be separated from pyrite. However, although the minerals are well liberated, the separation of chalcopyrite from pyrite in the cleaner stage is not always straightforward. The surfaces of the fine particles, produced during regrinding, are more easily oxidised and contaminated than coarse particles, directly influencing the particle floatability. The depression of pyrite is difficult in the cleaner stage as well due to copper activation, a process which is also highly dependent on the grinding environment. In this study, different grinding media, including mild steel and stainless steel, was used in the regrinding to produce different regrinding chemistry, such as, pH, Eh, and iron hydroxide contamination. The effects of regrinding conditions on chalcopyrite flotation and its separation from pyrite were studied. It was found that the stainless steel grinding media, which produced an oxidising environment, was more beneficial for the separation of chalcopyrite from pyrite after regrinding. The mild steel grinding media had a detrimental effect on both chalcopyrite and pyrite flotation. This study addresses the importance of choosing suitable regrinding conditions in the pyrite and copper flotation circuit.CITATION:Chen, X, Peng, Y and Bradshaw, D J, 2012. Effect of regrinding conditions on the flotation of chalcopyrite and its separation from pyrite in the cleaner stage, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 279-286 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

By M A. Gontalves, A F. D C Varajpo, S A. Stachissini

Clays from the Santa Elena Peninsula, south-east of the Ecuador coast, were investigated with a view to identifying their main mineralogical, physical, chemical and textural characteristics as well as their potential for industrial use as adsorbents. Identified as calcic bentonites, two representative samples from the Tosagua Formation (Oligocene to Lower Miocene) were selected for acid activation trials. The selection criterion was based on the greatest amount of clay fraction (<2 ¦m fraction) associated with the greatest content of montmorillonite. For the activation treatments, HCl and H2SO4 solutions of 4, 6 and 8 N were used in a stirred glass reaction vessel with the clay sample under reflux during four hours at temperatures of 70¦C for HCl and 85¦C for H2SO4. Mineralogical analysis by X-ray diffraction (XRD), chemical analysis by X-ray fluorescence (XRF), differential and gravimetric thermal analysis and measures of density, surface area and porosity indicated the changes occurred in the crystal structure of the montmorillonite. The acid treated clays were utilised in trials of purification and decolourisation of soybean vegetable oil in a ratio of 2:100 (clay/oil) at 90¦C for 30 min, under constant stirring. After centrifugation of the suspension, the wavelength of the bleached oil was measured by UV-visible spectrophotometer and the bleaching capacity of the clays was determined. The best bleaching capacity of the samples was obtained with 6 N H2SO4 acid-activated clays. The bleaching capacity was compared to Tonsil, a commercial acid-activated clay and similar results between them evidenced the potential industrial application of the Ecuadorian clays to bleaching of vegetable oil.

Jan 1, 2008

By Kohra A, Shoji S

The amount of copper production by flash smelting process occupies about 17% (equivalent to 1.4 million t/year) of total free world production. In Japan, 650,000 tons of copper is produced annually by flash smelting. This is 65% of the gross copper production of Japan. To reinforce pollution control, promote energy saving, and enhance production efficiency by increasing the size of furnaces, conventional blast furnaces and reverberatory furnaces are being replaced with the flash smelters worldwide. The Ashio Smelter started copper production in 1884 and developed in association with the Ashio mine. In those days, the Ashio smelter produced copper by using the blast furnace process designed for the high-grade ore from the copper mine. At that time, this process was specialized in Japan. In 1956, for the first time in Japan, the Ashio Smelter introduced the flash smelting process developed by Outokumpu Oy of Finland (it is suitable for treating the copper concentrate, producing sulfuric acid and improving production efficiency). The flash furnace in Ashio, the first ever in Japan, had a capacity of 230 t/day for copper concentrate and was operated up to 1962. During this period, various operational troubles were solved, and further improvements were made; and, in 1962, a Furukawa-type flash smelting furnace was completed in Ashio. This improved version of a flash furnace had a capacity of 450 t/day. There was one flash furnace and one waste heat boiler, which were arranged in a unique pattern for that time. This furnace may be said to be the prototype of the present flash smelting process in the world.

Jan 1, 1987

By M McLean

This paper deals with change strategies on brownfield and greenfield sites in extractive industries. It draws upon contemporary experiences across Australian, Indonesia and Papua New Guinea (PNG). Change strategies can be used when owners of an extractive industry operation want to optimise their resource. This paper draws upon many tried and proven theories and practices, including the findings of the Tavistock Institute (Trist, Emmery, Bamford, Jaques), as well as the concepts of Adult Learning espoused by Malcolm Knowles and is supported by learnings of Australian based management consultants. This paper reviews a range of approaches that have succeeded in the integration of systems, machines and people, with the key corporate objectives of: increasing productivity; decreasing cost; improving on-time delivery performance and achieving long-term survival. Such integration needs to be measured to show the outcomes from the change strategies and the authors have worked within many measurement regimes and metrics but for the most part, found that JaquesÆ set of metrics being æquality, quantity, resources and timeÆ has gained currency across many Australian operations. This paper contends that investing money in machines alone without a commensurate investment into the people side is counter-productive. Further, if there is not an understanding of processes, ie stable and capable, core and support processes, then all that new technologies will do, is to make what is done badly, only quicker. Recent interventions for the most part, have been cognisant of this balanced approach towards change management. The change strategies described are across extractive industry implementations, using a number of tools and techniques drawn from Continuous Improvement and Six SigmaÖ (registered trade and service mark of Motorola Corporation, USA).

Jan 1, 2006

The Quioma Mine is located along the axis of the Cordillera Oriental, 130 km southeast of Cochabamba, South Central Bolivia. Silver, lead, zinc, antimony, and gold have been intermittently produced from veins in the Quioma area since Colonial times. Mineralization occurs within steeply dipping fissure veins transecting moderately folded Lower Ordovician sediments. Tectonic activity is early to mid-Tertiary and the vein system parallels the fold axis of a major northwest-southeast striking, doubly plunging anticline. Vein sets occur within a 2 km wide band over a strike distance of 13 km along the northeast limb of the anticline. Economic mineralization occupies syntectonic pre-mineral fault zones developed in more competent stratigraphis units of Lower Ordovician clastic sediments. Veins average 55 cm in width, although mineralized structures up to 3 m wide with a known strike length of several hundred meters have been mined. Mineralization consists of siderite, argentifferous galena, sphalerite, and quartz, with minor amounts of chalcopyrite, barite, and bournonite. Pyrite is rare except at the Boston vein where it occurs with stibnite that contains trace amounts of gold. A marked characteristic of veins in the district is evidence of repeated stages of movement during mineralization. Intrusive rocks are rare in the Quioma area. Narrow porphyritic dikes of Andesitic composition averaging 1 m in thickness have been observed. These dikes occasionally show a close spatial relationship to the veins and are often kaolinized and carbonitized. Vein and dike contacts are sharp and alteration does not appear to extend into the wall rock. Mineral zoning is suggested by antimony mineralization observed in peripheral areas of the anticline.

Jan 1, 1987

By R-H Yoon

Increasing the upper particle size limit of flotation would allow operators to increase mill throughput, save operating costs, simplify flow sheets, and increase rate of return. However, coarse particle flotation is difficult for various reasons, of which bubble-particle detachment has been identified as the major limiting factor. In the present work, the process of bubble-particle detachment has been studied by directly measuring the forces required to detach air bubbles from hydrophobic solids. The measurements were conducted using a hanging balance apparatus. The measured forces were converted to detachment energies that can be compared with the work of adhesion, which in turn is a function of hydrophobicity, surface tension and contact area. The results were converted to detachment energies using the Young-Laplace equation for capillarity. In the present work, the solid surfaces were hydrophobised by coating them with octadecyltrichlorosilane and cetyltrimethylammonium bromide. The results show that bubble-particle detachment occurs in two steps. In the first step, air bubbles are deformed, while the three-phase contact (TPC) line is pinned, until contact angle reaches advancing angle. In the second step, the TPC line moves along the surface until solid/air interface is replaced by solid-liquid interface. In general, the energies of detachment measured in the second step are in good agreement with calculated work of adhesion. Thus, the energy required during the first step effectively represents an energy barrier for bubble-particle detachment. It has been found that the energy barrier varies with surface roughness and surface tension. The results of the present investigation suggest, therefore, that coarse particle flotation can be improved by control of particle hydrophobicity, surface roughness, and surface tension.

Jan 1, 2005

Models of the genesis of existing ore oodles and targetting of exploration for new mines are greatly enhanced by an-understanding of the plate tectonic environment existing at the time of mineral emplacement. In areas of recent or active tectonism, a study of the present-day crustal and upper mantle structure is an obvious starting point in unravelling the evolution of the accessible upper crust. Bougainville is the northern-most island in the Solomon Islands arc. A 7km deep trench almost 100km off its western coast marks the commencement of subduction of the Solomon Sea plate beneath the Pacific plate. As outlined by the seismicity, the subducted crustal slab under the southern half of Bougainville reaches the axis of the island at about 100km depth, from which point it dips near vertically another 300km into the upper mantle. Large surface blasts at the Bougainville Copper Mine at Panguna, Bougainville, Papua New Guinea were used to derive an unreversed upper crustal profile of the island. The crust appears to be relatively simple, being comprised of a 5km deep layer with a P-wave velocity of 4.5km/sec, overlying a l0km thick layer with a P-wave velocity of 7.2km/sec. Constraints on the 15km mantle depth were provided by the identification of both P to and S to P phase conversions of seismic waves from local shallow earthquakes at the Moho boundary. An upper mantle velocity of 7.95(¦ 0.15) km/sec was measured from travel times of selected shallow earthquakes along the strike of the island arc.

Jan 1, 1987

By M Schmid

German hard coal mining operations have decreased for more than 40 years. Current political decisions are leading to a discontinuation of subsidised black coal mining by the year 2018. This decision will, however, be reviewed once again in the year 2012. The enormous increases in productivity, which were achieved in previous years, have so far not led to an achievement of market requirements. Coal mining at depth of more than 1200 m in multiple seam environments is not yet competitive in global comparison. In 2008 the 24 faces left in eight mines produced about 20 million tonnes of usable steam coal. Management and the workforce will be reduced in parallel; from today until 2012 by more than half. The average age of personnel is increasing dramatically and nearly no new personnel are recruited. With this background in mind, increasing continuously coal mining productivity becomes more and more difficult. Above all, this goal was reached by mechanisation, then by increasing the mining machine power and then by enhanced machine control systems. The first attempts to automatically operate full face equipment from above ground were in the early 1980s. After successful automation of the face equipment, the emphasis is now on mine logistics. Autonomous monorail transport was introduced and tested in 2007. Since the development rate of machine improvements has its limits, the focus is on the full interaction of the total production system. Here information technology (IT) becomes important; the driver for more productivity. Actual developments aim for the complete and general homogeneous IT infrastructure both above ground as well as underground. The explosive environment needs high level investments in safe technology, eg access points for WLAN and fibre optics for underground use (ATEX certification). New technology availability also drives the enhancements of management and process control systems. Innovations in the mining industry often comprise technology advances through the adoption of well-known technologies. With virtual reality (VR) teaching and training systems advanced computational instruments, both in software and hardware development, were applied in the German coal mining industry for ten years. Widening lists of applications as well as the encouraging achievements show the economical benefits of investing in virtual reality technology both for teaching and training and for knowledge management. The paper discusses the actual technical achievements as well as in IT infrastructure utilisation and also in employment of virtual reality based systems. Special focus and deeper insight will be given to the fibre optics and WLAN hardware integration as well as software developments. The pocket personal computer (PC) is used to enhance underground material transport and data acquisition. The knowledge-based maintenance system (KBMS) integrates real-time virtual reality knowledge elements, such as repair process descriptions. It gives access to expert documentation by intelligent search algorithms and 3D representations of major mining machinery.

Jan 1, 2008

By Fullagar P. K

In resource definition and mine development, major capital expenditures are committed on the basis of sparse information and even in production surprises such as bad ground are not uncommon. Drill holes constitute the principal source of information about the orebody and its environment and optimisation of drilling implies maximising the yield of useful information per dollar expended. Geophysical borehole logging provides new flexibility for optimising the drilling budget. Economic benefits can flow from geophysical logging at all stages of the mining cycle. The most commonly cited benefit is substitution of diamond delineation drilling with cheaper percussion or reverse circulation drilling in cases where geophysical logs can substitute for core. This approach can deliver an attractive direct saving in drilling costs (and time) if drill meterage is unchanged, or a potentially greater indirect benefit from better ore control if more holes are drilled within the original drilling budget. More ore contact intercepts per dollar can translate into lower dilution and enhanced ore recovery, thereby increasing revenue as well as reducing mining costs. Substitution of diamond drilling with percussion drilling is not always feasible. However, geophysical logging of diamond holes is often highly advantageous in its own right, both for geotechnical characterisation as well as ore delineation. Operational advantages of logging include data objectivity, speed of interpretation and reduced core handling and analysis costs. Geophysical logging assists mining engineers by providing a continuous measure of in situ rock strength, even over intervals with poor core recovery. The additional expense of geophysical logging in blast holes can be justified in terms of more accurate ore boundary delineation and rock strength evaluation. Precise ore boundary delineation permits refinement of charge placement, to minimise dilution and maximise recovery. Detailed knowledge of rock strength can enable optimisation of blast design. Rock strength can be evaluated in real-time via analysis of drill performance data recorded with measurement-while-drilling (MWD) technology. To successfully apply geophysical logging in mines, its technical, operational and economic viability must all be established. This entails verification of the existence of appropriate physical property contrasts, investigation of the best way to integrate the geophysical results with the mining method and an objective assessment of the value of the resulting mine performance benefit. Geophysical logging is already well established in many mining operations. The greatest impediments to its wider utilisation at mines are: lack of appreciation of geophysics by most mine geologists, engineers and managers; limited interpretational aids; and the necessity to re-enter completed drill holes. In this paper we endeavour to address these issues by informing mine geologists about potential applications of geophysics, by illustrating automated interpretation of geophysical logs and by highlighting the importance of emerging MWD and logging- while-drilling (LWD) technology.

Jan 1, 1997

By L. Gilbert

Recent changes to environmental legislation and trends in the environmental regulation of mining in the Northern Territory are being driven by (among other factors) Federal Government policies and international agreements on the environment. These trends are discussed and the expected application of the NT Water Quality Management Strategy (based on the National Water Quality Objectives) over the next few years is examined with respect to mine environmental management practices. Some of the potential conflicts and changes in approach which may develop are identified and examples discussed. Proactive means of integrating trends in environmental legislation with mine planning and waste management are discussed.

Jan 1, 1994

By G Varley

This paper describes the mining methods and strategy used to extract the 5 Orebody crown pillar at the Isa Lead Mine over the past five years. The bulk of the crown pillar was extracted by the use of sublevel open stope method. An uphole bench stope was mined to scavenge the remaining ore. Geomechanical issues associated with the crown pillar extraction are described. Stope sizes were gradually increased on a stope by stope basis. This has allowed the maximising of ore recovery while relevant risks were managed. The principles in designing ore rib pillars against various types of fill materials are also described.

Jan 1, 2002

By H S. Shin, H Jin, B H. Ryu, J Lee

Prospecting ice on the Moon necessitates drilling systems to obtain subsurface samples and measure the composition of ice deposits. Landers and rovers equipped with drilling equipment are essential for analysing ice and subsurface resources located at the Moon’s poles. These devices must be small, lightweight, low-power, highly efficient, and high-performance units to function properly in the extreme conditions of the lunar environment. Researchers have developed a prototype drilling apparatus capable of operating in atmospheric and cold environments. A newly developed drilling system in Korea, capable of performing not only sampling but also subsurface investigation, is introduced.

Sep 1, 2024

By R R. J McAllister, K Moffat, S Heyenga

This paper examines the statistical relationship between quality of life indicators and the gross value of mineral production from Australian regions. We used quality of life indicators, aggregated for 673 local government areas, of household income, housing affordability, access to communication services, educational attainment, life expectancy and unemployment. We find no evidence of systematic negative associations between quality of life and the gross value of minerals production. Instead, mining activity has a positive impact on incomes, housing affordability and communication access across regional and remote Australia. Whilst we do not establish causality between mining activity and quality of life, our analysis prompts a rethink of the æresource curseÆ as it applies within a single country. Nevertheless, our findings are tempered by extensive anecdotal and empirical evidence of the negative social impacts of mining on specific demographic sectors, localities, families of fly-in, fly-out mining operations and individuals. This contrast may be a scale issue, with the regional benefits of mineral wealth masking highly-localised inequalities and disadvantage. We suggest that there is a need to better understand these impacts and, more importantly, the types of policy mechanisms government and industry can adopt to mitigate or avoid them.

Jan 1, 2009

By K Koskinen, S Ronkainen

The flow field induced in an Outokumpu TankCell and by an OK rotor-stator mixing device in a laboratory and a process size flotation cell was modelled numerically using computational fluid dynamics (CFD). The primary target was to discover and reproduce the various interactions between the flow field and the flotation cell by numerical means. As power consumption depends sensitively on flow field, it can be regarded as a top-level derived quantity (or measure/metric) indicating the validity of the numerically obtained flow field. Having properly validated numerical means to produce the flow field the influence of various design parameters can be captured with certain accuracy. In addition, separate gas and solid phase models for bubbles and solids, respectively, were implemented. The comparisons between velocities and turbulence quantities measured using the laser doppler velocimetry (LDV) technique and CFD modelling were performed. The grid generation was performed with the commercial Gambit 1.3 and the subsequent integration and solving of the resulting algebraic equations with the commercial CFD-code Fluent 6.22. The computationally economic multiple reference frame method was included to model the moving rotor blades. Gas and solid phase models were modified mixture models.

Jan 1, 2005