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By M Sebbag, T Taimre

Barrick Gold Corporation is proceeding with development of the Buzwagi Mine in the Lake Victoria Greenstone Belt District of Tanzania. The Buzwagi orebody occurs in the Nzega Shear zone within the Greenstone Belt and is hosted in a K-Feldspar rich granite in contact with mafic volcanic. The orebody presents 2.6 M ounces in 41 Mt of reserves, at 2.0 g/t. Over the ten year mine life, total material movement will be 261 Mt. The feasibility study was completed in 2006 and presented several technical challenges. Two principle challenges are grade control and the impact of dilution on the economic viability of the project. The principle challenges for grade control will be quality control and quality assurance in the sampling of the massive coarse grained granite, which comprises 70 per cent of the deposit. The principle challenge with dilution will be with the selective mining of the narrower mineralised zones contained within the mafic volcanics. This paper will focus on the mine planning methodology which has been applied including selective mine unit (SMU) and dilution estimation, net smelter revenue (NSR) calculation and the effects of cut-off grades to the project economics and mine schedule.

Jan 1, 2007

Role of Bubbles in the Action of Flotation Agents

Sep 13, 2010

By A Rojc, J Ronaszeki, C Smith

Nuclear logging was tested for the in situ determination of Fe, Si, and Al in iron ore blastholes with field tests at the BHP Billiton Iron Ore, Mount Waleback Mine. Prompt gamma neutron activation analysis (PGNAA) was used to determine percentages of Fe and Si while natural gamma logging was employed for the determination of Al. The accuracy given by nuclear logging is comparable to the accuracy provided by the laboratory analysis which was determined by taking the average of four samples collected from the cuttings deposited on the surface around the perimeter of a drill hole. The work also indicated that there is a chance of determining Al by PGNAA.

Jan 1, 2002

By S M. Aminossadati, R Bagherpour, F Hasheminasab

Mine ventilation is an essential part of underground mining operations used to provide fresh and cool air, as well as to dilute and remove contaminants from the work environment. This paper presents an overview of the ventilation and gas management systems in one of the underground coalmines in Iran: Parvadeh_1 mine. The mine is located in the Tabas coalfield in the South Khorasan province. It is the only fully mechanised mine in Iran utilising the longwall retreat technique. The mine produces 1.1 to 1.3 Mt of coking coal annually. The mine ventilation system currently utilises two 630 kW exhaust surface fans. The gas management system includes surface to in seam (SIS) predrainage boreholes. The underground mine is equipped with an underground gas reticulation pipeline that is connected to a surface plant for the production of methane gas. This study shows that the ventilation and gas management systems of the Parvadeh_1 mine are in line with the standards of Australian underground mines.CITATION:Hasheminasab, F, Aminossadati, S M and Bagherpour, R, 2017. An overview of ventilation and gas management systems in an underground coalmine in Iran, in Proceedings Australian Mine Vent Conference 2017, pp 41–46 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

By A Hekmat, M Fuentes, F Armijo, R Castro, F Rodriguez

Interpreting the behaviour of granular material and simulating the gravity flow are complex processes in cave mining methods. In this paper, a new Cellular Automata based code – FlowSim – is used as a flexible tool to simulate the gravity flow and subsidence zone in block caving mines. The simulation results of the gravity flow model in a real scaled mine as well as a scaled physical model are presented in this study. In this research, FlowSim was first calibrated at a mine, based on the information obtained from smart markers. These markers were located in five points of the second block of the Esmeralda sector, at the El Teniente copper mine, Codelco, Chile. The calibration was performed with the objective of reducing the discrepancy between the extraction zone defined by markers in the mine and FlowSim outputs. Regarding the mine data, FlowSim was calibrated with the minimum error of ten per cent between real and simulated results. Then, the calibrated FlowSim model was used to simulate the flow behaviour of a scaled physical model. This model was constructed in the Block Caving Laboratory of the University of Chile to scale down the same block of the Esmeralda sector with the scale of 1:200. The FlowSim outputs show that this software enables the simulation of the gravity flow of the scaled model with less than five per cent discrepancy in grade and dilution entry to the drawpoints. According to the obtained results, this paper recommends FlowSim as an appropriate tool which can improve the design of production level in block caving and can enhance the prediction of the subsidence zone and dilution entry.CITATION:Castro, R, Hekmat, A, Fuentes, M, Armijo, F and Rodriguez, F, 2016. FlowSim – a versatile flow simulation tool to quantify extraction and design alternatives for block caving, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 645–652 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

Python Underground Processing Plant Critical Design The use of continuous gravity recovery in combination with a controlled breakage fine crushing and screening system followed by flash flotation has been incorporated into the Python processing plant. This provides miners with a flexible, robust, low cost, low energy pre-concentration process for the recovery of gold and/or heavy minerals. The Python plant incorporates fine crushing utilizing either High Pressure Grinding Rolls or Vertical Shaft Impactors in combination with the InLine Pressure Jig and Flash Flotation to continuously liberate and recover the valuable minerals. The use of these technologies has enabled a narrow, transportable pre-concentration plant to be produced which can easily be installed and operated in underground drifts and tunnels.

Sep 13, 2010

By H Han, L Lu

Due to the international depletion of reserves of traditional high-grade iron ore, the ore resources available throughout the world, especially in steel mills in East Asia, have changed drastically from hard hematitic to more goethitic ore types, such as pisolitic and Marra Mamba ores. The level of impurities and loss on ignition in iron ore has also been slowly increasing. Finally, the proportion of fine material in the available products has increased considerably for most iron ore fines. This has been found to have significant impacts on sinter quality and sintering performance. Magnetite concentrate is typically high in Fe grade and releases extra heat when oxidised to hematite. The amount of magnetite concentrates is expected to increase due to the recent development of a number of magnetite projects. Some of these magnetite concentrates will end in sinter blends. This will not only improve the sinter quality and but also have a beneficial impact on the fuel consumption of the sintering process. However, most of the concentrates available are very fine, which will negatively impact the green bed permeability and consequently the productivity of the sintering process. This paper reviews and comments on the recent technological advances in sintering with high proportions of magnetite concentrates.CITATION:Han, H and Lu, L, 2017. Sintering technologies of sinter mixtures containing high proportions of magnetite concentrates, in Proceedings Iron Ore 2017, pp 31–38 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

Some crystal chemical properties of several apatites from Brazilian deposits and occurrences were determined; the samples had different origins (igneous, metamorphic and sedimentary). The aim was to establish relationships to their froth flotabilities behaviour. Detailed X-ray diffraction studies were carried out, to determine precisely the unit cell parameters and the degrees of crystallinity of the apatite samples. A thorough chemical analysis of these minerals was also conducted. Microflotation studies were carried out, using sodium oleate and dodecylammonium chloride as collectors. The crystallinity levels were determined for all samples studied, with the establishment of a crystallinity index, which varied from 10.0 to 4.5, on a normalised scale. A marked dependence was observed between this crystallinity sequence and flotability; for both collectors, flotability dropped drastically for crystallinity indices lower than 8.0. Also, the low crystallinity apatites showed a decrease in floatability, for longer conditioning times.

Jan 1, 1993

Effect of Anionic Surfactant on Silica Particle Attachment at the Oil-Water Interface Controlling particle attachment is crucial where powdered solids come into contact with oil and water. Particles are trapped in a deep energy well at the oil-water interface, stabilising emulsions. Here it is shown that adding anionic surfactant causes dramatic changes to the bulk and interfacial structure of silica particle-stabilised oil-in-water emulsions. Exposing particle-stabilised drops to surfactant concentrations above the critical micelle concentration enhances the rate and extent of creaming and flocculation. Mixing particle-stabilised emulsions with surfactant solutions causes drop fragmentation. As the surfactant concentration increases, the average drop size decreases and particles are displaced from the interface during the mixing process.

Sep 13, 2010

Beneficiation of Iron Ore - Washing with Surface-Active Agent The stability of the dispersed phase in 10 wt per cent slurry of iron ore slime and fines was studied at pH 5 and different concentrations of surface-active agents. The behaviour of the dispersed phase of iron ore slime and fines is different for different surface-active agents. The improvement of iron value of slime and fines in the presence of surface-active agent is best realized at pH 8, where the Al2O3/Fe and Al2O3/SiO2 ratios in the concentrates are appreciably reduced. The polar functional group like -COO- interacts with hematite surfaces and forms outer- and inner-sphere surface complexes depending on the suspension pH and adsorbate.

Sep 13, 2010

Population growth, social inequality, pollution, global warming, poverty, overexploitation of natural resources and biodiversity loss, are a few examples of the many challenges facing the world today. Sustainable development is about meeting these challenges and improving the standard of living for the benefit of the maximum number of people. These issues concern governments, communities, environmental and social action groups and individuals all over the world. Business too, has a fundamental role to play in delivering sustainable development. In particular, sustainable development is becoming increasingly recognised as a critical issue for the oil and gas industry to address and act upon. BP is committed to positively respond to the challenges posed by the objective of sustainable development.

Jan 1, 2002

Slime Flotation Using Ethoxylated Surfactants in Solutions of the Electrolytes

Sep 13, 2010

Disasters are often tragic outcomes of high-risk technologies such as mines. In Australia, more mines are being developed every day, and the risk of disasters is ever increasing. No matter how effective our conventional safety devices are, there is a form of accident that is inevitable. These relate to accidents that result from æinteracting failuresÆ in a way that could not be foreseen by the designers. In so-called ætightly coupled production systemsÆ (processes that happen very fast, such as on a high producing mine) the risk is even higher and our risk controls mostly introduce some sort of a technological fix. While we are at the one hand attempting to control the risk, we are also introducing another level of complexity. Are we really controlling the risk? This is one of the fundamental questions that will be addressed in this paper: Do we have the ability within the mining industry and other industries to effectively prevent these catastrophes, or are we, on the contrary, faced with an increasing risk as a result of increasing complexities of our technology, management systems and practices. This paper will contend that perceived improvement in risk control is an illusion of activity, and that the likelihood of mining catastrophes may be exponentially increasing. Although the paper focuses on the mining sector many aspects may be applicable across a range of industries. This paper will further contend that we are applying the right solutions to the wrong problems. Our focus is technological and procedural, while our problem is one of production cultures ripe for error and failure.

Jan 1, 1999

By W J. Rankin

A study was carried out to compare the environmental impacts of a number of process routes for lead and zinc metal production from sulphide ores using Life Cycle Assessment methodology and based on average industry data derived from the literature. The processes investigated were:blast furnace production of lead; Imperial Smelting Process for lead and zinc production; and electrowinning of zinc with the mining and mineral processing stages common to all three routes. The effect of a number of process variables, namely ore grade, fuel source for electricity generation and efficiency of generation, on the environmental impacts was also examined. The environmental impact categories considered in the study were:total (or full cycle) energy consumption; Global Warming Potential (GWP); and Acidification Potential (AP). The results of the study show that when produced separately, zinc production is more than twice as energy intensive as lead production (viz 48 and 20 MJ/kg respectively), however when produced jointly by the Imperial Smelting process, the energy intensity of the two metals is not all that dissimilar (viz 36 and 32 MJ/kg respectively). The metal production and refining stage was found to make the greatest contribution to the overall environmental impacts for all three processes. The study also highlighted the importance of taking a life cycle approach when comparing the environmental impacts of different processes.

Jan 1, 2002

By G C. Sen

All mining and quarrying operations that employ blasting to fragment and move broken ground have a price to pay for æby-productsÆ such as vibration and noise. These æby-productsÆ cannot be eliminated but they can be controlled and modern blasting techniques have improved to the point that excessive environmental restrictions can be adhered to whilst maintaining acceptable production rates and quality. Accurate measurement is the key to control, and as the environmental limits are becoming tighter, the proper way to measure vibrations from blasting operations becomes an integral part of the mining or quarrying operations. The basic vibration monitoring system consists of a primary sensor connected to a data logger and computer software for the analysis of the signal received and recorded. Currently, as with all fields of measurement, much improvement has occurred over the past decade, and electronic devices are much more accurate and reliable. Data analysis has also improved considerably with the computing power that is available to field operatives today. Mounting the primary sensor has been often overlooked in supposed æstandardsÆ with procedures such as double sided tape, resting on a flat surface provided the vibration level is less than a given amount. But if it is worth going to the expense of the monitoring equipment and manpower, surely it is worth a little extra effort to ensure the primary sensor is coupled to the ground effectively. The primary sensor must move with the ground and measure this movement; so if the primary sensor is allowed to move without respect to the ground (ie poor coupling to the ground) then a false record of the physical event will be measured. This scenario can easily be a practical reality if the primary sensor coupling method to the ground is not effective. In this study a number of mounting methods were fabricated and connected to similar data monitors and a series of ænormalÆ production blasts were used as the vibration source. These mounting devices were measured against an in-house procedure (the æstandardÆ) and the relative merits compared. A laboratory investigation was also carried out to look at the physical parameters of the æsoil and their effect on vibration attenuation of the in-house standard method.

Jan 1, 1999

By S Sandover, D Glenister

Alcoa World Alumina Australia is committed to sustainability principles as a basis of business success into the future. In March 2001, Alcoa Inc chairman Alain Belda announced a set of far-reaching environmental goals for the corporation, with the challenge that they should be achieved in ways that enhance economic and social performance, while substantially reducing environmental impact. Application of Cleaner Production methods is seen as the key to achieving these joint objectives. In Australia Alcoa has launched a co-ordinated effort to accelerate our application of Cleaner Production principles to delivering cost-effective in-process solutions to environmental issues. Our Western Australian Operations are a signatory to the WA Cleaner Production Statement, through which we provide a Cleaner Production Plan to the State Government on a voluntary basis. This paper describes in general terms AlcoaÆs goals, achievements and directions in applying Cleaner Production to enhance business performance in the economic, environmental and social dimensions. Quantification of the benefits and tracking of progress in quantitative terms is a key challenge for the future

Jan 1, 2002

Fine Gravity Separation in the Reflux Classifier, Exploiting a High Shear Rate, Laminar Flow Mechanism The Reflux Classifier is used in the gravity separation of particles over a broad range of particle sizes. The device consists of a fluidised bed zone, with a system of parallel inclined channels above. The inclined channels provide a significant hydraulic advantage over conventional fluidised beds via the so-called Boycott Effect (Boycott, 1920). This paper describes a new advance in fine gravity separation based on the high shear rate and laminar flow profile that arises when closely spaced inclined channels are deployed. As reported recently (Galvin et al, 2009a), a powerful density based separation mechanism develops from this arrangement, suppressing the effects of particle size. In this paper we focus on two areas, firstly the application of the separator in the laboratory for batch fractionation of particles of varying size and density to determine the grade recovery curve and hence the liberation, and secondly the step change in separation performance achieved on a continuous steady state basis when closely spaced inclined channels are used. The variation in the separation density with particle size decreases significantly, and the Ecarte Probable Error (Ep) remains at low levels over a broad size range.

Sep 13, 2010

Grade control is a real challenge, and better sampling and modelling practices are among the tools that have proven efficient in improving it. Although based on rather trivial examples, this paper addresses the following important issues: How much of a challenge is it? How and to which degree can it be improved? And what kind of economic benefits should be expected in return for the corresponding efforts?

Jan 1, 1999

By R Kerrich

Early-Archaean (3.26 Ga) volcanogenic massive sulphide (VMS) deposits located within the low strain and sub-prehnite-pumpellyite metamorphic-grade Strelley greenstone belt, East Pilbara, Western Australia, contain exceptionally well preserved sulphide textures which are directly analogous to those of sulphide chimneys formed by black smokers at present day submarine hydrothermal vents. The VMS deposits are associated with seafloor alteration zones in and below silica-carbonate laminites, at the top of tholeiitic to calc-alkaline intermediate and felsic rocks. VMS mineralisation comprises stratabound Zn-rich sulphide lenses with significant Cu and barite, and variable Pb and Ag, above Cu-rich stringer zones, all of which are similar to Phanerozoic polymetallic or Kuroko VMS deposits. Sulphide-sulphate mineralisation implicates hydrothermal discharge into sulphate-bearing ocean waters, ruling out a globally anoxic Archaean hydrosphere. The volcanic rocks and co-magmatic sub-volcanic intrusion hosting the VMS deposits are characterised by the conjunction of LILE>LREE>HREE, and Phanerozoic La/Yb with negative normalised anomalies of Nb, P and Ti, consistent with derivation via subduction zone hydrous metasomatism fusing the mantle lithosphere.

Jan 1, 1995

Bubble Load Measurements in Flotation - A Critical Review of Current Practice

Sep 13, 2010