Search Documents

By LefTvre Y

In May 1991, AZSA commissioned a new conventional Cell House. This paper focuses on the major improvements introduced in the design and the construction of the equipment, machinery and control. An effective control system together with good reporting and routine operation has resulted in quality control of the Cell House at the highest possible level. Consequently the monthly current efficiency consistently averages above 93 per cent with a total energy usage of 3000 AC kWh/t of cathode zinc. The new concept for the year 2000 and beyond is introduced.

Jan 1, 1993

By G Chitombo, G Lewis

The knowledge of the expected run of mine (ROM) fragmentation during the feasibility study of a green field site is essential for the design of downstream crushing and milling processes. However,the prediction of blast fragmentation can be a challenging process due to the uncertainty related to the blast design and rock mass parameters. In general,a number of possible blast designs are considered in a feasibility study,with factors such as bench height and blasthole diameter influencing the design. Rock mass parameters are normally derived from a limited number of geotechnical diamond drill cores. Although diamond drill core can provide detailed information concerning intact rock strength (unconfined compressive strength and point load),it provides limited structural information to predict the in situ block size distribution of the rock mass. The in situ block size is an essential input to the prediction of the fragmentation distribution, in particular the coarse end. This paper outlines the methodology of blast fragmentation modeling undertaken for a green field feasibility study at the Riska gold deposit in Indonesia. The favoured milling process for the feasibility study was dump leaching,with no crushing of the ore material extracted from the pit. For this reason,blast fragmentation was a critical issue to be addressed by the study. A range of blast designs were considered with bench heights and blasthole diameters ranging from 4 m to 7 m and 76 mm to 102 mm respectively. Rock mass data was obtained from 19 diamond drill cores across the deposit (total drill length approximately 2200 m). Intact rock strength was estimated from qualitative strength descriptors,while the in situ block size distribution of the rock mass was estimated from the Rock Quality Designation (RQD) of the core. The methodology of fragmentation prediction involved a number of steps including the estimation of rock mass parameters from diamond drillhole data including the estimation of the in situ block size, delineation of blast domains within the deposit,and the assessment of the impact of various blast design parameters and rock mass variation on the predicted fragmentation distribution. The modelling process for the Riska green field site highlighted the need for additional rock mass data to be collected post feasibility stage and once the development of the mine commenced.

Jan 1, 2004

By B G. Lottermoser

Phosphate induced stabilisation has been used to create passive iron phosphate coatings on pyrite and pyrrhotite. The formation of solid phosphate coatings on sulfide grains thereby inhibits sulfide oxidation. The aims of the study were to determine whether phosphate induced stabilisation could control sulfide oxidation and metal mobility in partly oxidised, polymineralic, sulfidic mine wastes. Waste materials were obtained from the acid mine drainage generating, abandoned Montalbion silver mine site, far north Queensland, Australia. The waste consists of quartz, kaolinite/illite, sulfide minerals (galena, chalcopyrite, tetrahedrite, sphalerite, pyrite, arsenopyrite), and pre- and post-mining oxidation products (hydrated Fe, Cu, Pb and alkali mineral salts). SEM observations of waste material treated with potassium orthophosphate showed that metal, metal-alkali and alkali phosphate coatings developed on all sulfides (with the exception of tetrahedrite). The abundance of phosphate phases was dependant on the availability of cations in solution for complexation with the phosphate anion. In turn, the release of cations was dependent on sulfide oxidation or the dissolution of efflorescent mineral salts. Experiments aiming to dissolve these phosphate coatings û using a strongly oxidising solution û showed that the phosphate coatings remained stable, preventing acid generation and metal release. The results of this study demonstrate that liquid phosphate stabilisers can suppress sulfide oxidation and immobilise metals in partly oxidised, polymineralic mine wastes.

Jan 1, 2003

By Cornwell P. J

The Pajingo ore bodies consist mainly of auriferous quartz veins hosted by a suite of hydrothermally altered andesitic pyroclastics, volcanics and epiclastic sediments. Scott lode, the main economic deposit in the area, lies in a zone of major structural disruption and contortion. High grade gold and silver mineralisation is selectively mined by open pit methods. Standard grade control techniques and extraction methods were adapted to minimise mining dilution and to maximise metal recovery. Basic blending of grade ranges at the crusher has produced an average 10 gram/tonne gold head grade. The estimation of ore reserves calculated by both standard polygonal and geostatistical methods proved acceptable. Mineable reserves when compared to in pit reserves defined by blast hole drilling, indicate a decrease in tonnes and an increase in the grade resulting in an acceptable comparison of the total ounces of contained gold. The ore reconciliation of mined against milled ounces indicates that both ore reserve and grade control models underestimate the metal content in the orebody. Sampling techniques are being examined in an attempt to reduce this discrepancy.

Jan 1, 1989

The necessity for good management and economic working in our mines and ore-dressing sheds is impressed upon us by the present low prices of all our metals. Silver, lead, copper, and tin have all suffered a heavy decline during the last six or twelve months, and many mines have been shut down simply on account of the low market value of the ore produced. After fully considering the position of the mining industry. I am convinced that considerable improvements will have to be made to make it as prosperous as it ought to be. The most obvious of these improvements are good management, good machinery, and as little interference by directors as possible. If these conditions are insisted upon and carried out efficielltly a poor mine may have a chance to weather the storm.There is no doubt that the present depression is the refilult of over-speculation and general loss of confidence by which the whole commercial system has been affected, and every branch has suffered more or less, mining not excepted. It has suffered heavy losses in the past, and the future is not over bright we are, therefore, compelled to be careful in everything by which mining is affected and savings can be secured.

By A Cooper

The current financial climate has given rise to fears that falling mineral prices and tight credit will force mining companies to cut back on production and new project development in a bid to cut costs and conserve cash. However, a prolonged squeeze on global supply can have only one result: a massive and potentially explosive demand for metals in the not-too-distant future. A resurgent global economy will also generate dramatic new demand for oil and energy, with a return to higher oil prices likely. How then should the mining industry plan for the future? In-pit crushing and conveying (IPCC) could lead the way as a partial or complete substitute for trucks. In 13 of 15 studies undertaken by Sandvik and Snowden, comparing IPCC with truck-optimised pit designs, IPCC generated operating savings ranging from US$0.18 to US$0.82 per tonne moved, compared to trucks. Trucks have higher operating, maintenance and energy costs than conveyors. New emission standards on diesel engines may make them more emission friendly but less efficient in terms of energy usage. With far more efficient energy use and cheaper operating costs per tonne moved than trucks, conveying offers an attractive alternative for the bad times ahead and into the apparent energy depleted future. When evaluating alternatives, a reasonable first step would be to conduct a scoping level study which analyses the differences in capital and operating costs between a truck and shovel operation and an IPCC solution. The study can also determine what type of IPCC is best suited to the particular mining application. The results can then be used to decide whether a more detailed study is justifiable. IPCC is a proven process that, with a fresh mindset, can make a significant improvement to mining operations. Sandvik (as an OEM with a full suite of IPCC equipment) can undertake these studies in ten working days in conjunction with Snowden or any other independent mine planner who knows how to schedule for IPCC. Because most mining industry personnel have been æborn and bredÆ on trucks and shovels û this paper focuses on some of the practical considerations necessary to make IPCC systems work that the Sandvik Technical Services Group has encountered during these studies.

Jan 1, 2009

It is difficult with inadvertent explosions to establish fundamental data, especially of original dust, of pressure, temperature etc. and of ventilation oscillations, as exposed personnel rarely survive. Retrospective data from explosions must be derived from damage, from fatalities, from ventilation analyses, from analyses of dusts and other indications of temp- erature and duration of temperature. The five disastrous explosions selected for analysis provide examples of what data can be established as to the cause and extent of explosions. Such information is required for legal etc., inquiries subsequent to explosions, but most importantly to give the best guidance for avoidance of possibility of further Disasters.

Jan 1, 1981

By T Higuchi, T Yamamoto, K Takehara

Iron ore fines are used as raw materials for sintered ore for blast furnaces in the world. Since the production and quality of sintered ore have a great influence on the stable operation of a blast furnace, many technologies were developed for controlling the heat profile in the sintering machine, which largely affect the sintered ore properties. In particular, the influence of oxygen in the suction gas, which plays an important role in combustion, was investigated over the years. It is known that increasing the oxygen ratio by about 30 per cent not only significantly improves the combustion rate, but it also increases the strength and yield of sintered ore. However, the details of the mechanism for improving these qualities are unknown. In this study, we investigated the influence of oxygen enrichment at higher ratios (O2: 21–40 per cent) and tried to understand the sintering behaviour enhanced by oxygen. The effect of oxygen enrichment on sintered ore quality and the heat profile were evaluated by sintering tests using a quartz glass pot. From the results, sintered ore yield had a maximum value for O2 = 30 per cent, but strength was increased for O2 = 40 per cent. From heat pattern analysis, it is clear that the high temperature holding time also reached a maximum at O2 = 30 per cent. Furthermore, we found that with increased oxygen ratio, the combustion speed (flame front speed) was increased, but the area of combustion was enlarged. It is considered that there could be a maximum oxygen ratio value for the yield from the balance of these positive and negative effects on high temperature holding time. To clarify the reason for strength improvement, thermodynamic calculations were performed and it was found that melting behaviour could be improved by changing the oxygen ratio.

Sep 18, 2023

By E Vargas, A Egana, M Alarcon, X Emery, A Barberan, A Lopez, N Morales, C Friedrich

"As the cost in time and money of data from sensors and small-scale tests has reduced, additional challenges have arisen. Although many mine data sets are not big relative to those in other disciplines, they are complex in other ways, and becoming too large to manage efficiently on personal computers. In order to take advantage of the opportunity offered by increased data, a diverse team from Universidad de Chile and CSIRO Mineral Resources has developed a virtual geometallurgical laboratory to support the computational requirements linking data acquisition with data-driven business decisions. A particular focus to date has been the development of user-guided workflow ensembles to enable comparison between plausible geometallurgical hypotheses.A case study has been undertaken using publicly available data from the Rocklea Dome iron deposit in Western Australia. A hypothetical mining schedule was produced from geochemical and hyperspectral drill core/chips data via the following steps: data preprocessing, exploratory data analysis, geochemical interpolation, block modelling, ultimate open pit design and scheduling. The key outcome of this study was the integration of workflow stages through new plug-in methods or modification of existing software. Outcomes from this study will be described in the paper in terms of geological and metallurgical data quality, analytical software support and ongoing computing infrastructure requirements.CITATION:Lopez, A, Barberan, A, Alarcon, M, Vargas, E, Ortiz, J, Morales, N, Emery, X, Egana, A, McFarlane, A and Friedrich, C, 2016. Progress towards Data-driven Mine Planning via a Virtual Geometallurgical Laboratory, in Proceedings The Third AusIMM International Geometallurgy Conference (GeoMet) 2016, pp 287–294 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 15, 2016

One of the responsibilities of the Melbourne and Metropolitan Board of Works is to provide a sewerage system for the metropolis of Melbourne which now contains over 2.5 million people. In providing this sewerage system it was necessary for the Board to embark on a large tunnelling programme some 20 years ago. As a result of this extensive tunnel construction programme, tunnel boring machines and shaft sinking methods have been developed to cope with the soft ground and soft to medium rock found in the southern and eastern areas of Melbourne where the majority of the recent tunnelling has been carried out. While in the last few years radical changes in construction methods have not been made, development has continued and improvements have been made, which have enabled the Board to extend the limits of the ground conditions in which it can efficiently construct shafts and also tunnels with boring Machines.

Jan 1, 1976

By Lockhart D. A, Gleeson P, Lang S. C

The Glenrock Group forms the uppermost part of the Early Devonian to Early Carboniferous Burdekin Basin sequence in the Townsville hinterland, north Queensland. As redefined, three formations make up the Glenrock Group. The Percy Creek Volcanics (base), the dominantly epiclastic Mount Douglas Formation, and the Horse Pocket Volcanics (top). The Ellenvale beds unconformably overlie the Mount Douglas Formation and Percy Creek Volcanics and have been excluded from the Glenrock Group as defined by Wyatt and Jell (1980). Three facies associations are recognised in the Mount Douglas Formation: Alluvial Plain facies, Alluvial Fan facies and Lacustrine facies.Deposition of the Glenrock Group, began with the eruption of massive basalt and basaltic andesite lavas, probably in a volcanic arc setting. With time, the volcanism evolved to become more dacitic to rhyolitic in composition. Waning of the volcanic activity appeared to coincide with uplift of source areas (probably to the west). Deposition on an alluvial plain during this waning volcanic cycle, gave way to alluvial fans at the margins of the uplifted terrain. As the uplift ceased and the system became more mature, the alluvial fans gave way to widespread lakes. Rhyolitic ignimbrite and airfall tuff, interbedded with the alluvial plain, alluvial fan and lacustrine facies, indicate that some volcanism continued, probably vented in the uplifted terrain to the west.

Jan 1, 1990

The Beaconsfield Gold Mine within the township of Beaconsfield in northern Tasmania has been established in recent years to exploit a known resource in the Tasmania Reef which was mined to a depth of 450 m below surface between 1877 and 1914 yielding 850 000 ounces of gold. Activity at Beaconsfield over the past 30 years has involved drilling to assess the resource and rehabilitation of the top 100 m of the Hart Shaft that had collapsed since the original closure. More recently the mine has been dewatered to the 375 m Level and work is well advanced establishing infrastructure aimed at recommencing production during 1998 - 99. This paper reviews geotechnical studies undertaken to-date and provides a brief overview of some practical methods of analysing ground conditions. It pursues simple observation and analysis as a tool for assessing mine design and ground support options without recourse to extensive monitoring and measurement and avoids the use of elaborate models before the basics are understood.

Jan 1, 1997

By Andrews JRG

Chrysotile asbestos is a valuable resource. Used as a reinforcement in asbestos cement, products are obtained which are cheap, are not attacked by vermin, do not rot or support growth of fungi and are unaffected by water or humid conditions. Such products are of great value in the developing countries where inexpensive and durable building materials and pressure pipe are very important to development, housing and water supplies. Concern over the adverse effects of inhaling asbestos has led to the introduction of increasingly stringent controls world wide on the quantities of airborne asbestos per- missible in the occupational situation. Wet processing has the potential for virtually eliminating the environmental concerns with asbestos dust both in fibre production and in the materials handling section of the manufac- ture of asbestos cement products. In addition, high efficiencies associated with wet process- ing mean that better yields are obtained and that the tailings which are dumped have a lower residual asbestos content. Since early 1977, ICI Australia and Woodsreef Mines have been engaged in a programme of research to develop and evaluate a wet mill- ingprocess to produce, from ore and existing tailings, high grade fibre suitable for use in asbestos cement products. The process has been developed through microscopic studies, labora- tory bench scale experiments, work in a small scale semi-continuous plant and product evalua- tion on experimental size Hatschek asbestos cement machines. A prototype mill with a normal feed rate of 1z tonnes per hour and capable of producing pipe grade asbestos from Woodsreef ore has been constructed and was operational from January, 1982 to July, 1983. A range of asbestos cement products have been made successfully on full scale Hatschek machines using fibre from ore and tailings milled in the prototype mill. Economic evaluations indicate that a wet process mill would be cheaper to build, operate and maintain than an equivalent dry process plant. A commercial plant has been designed 1. Manager New Process Development, Woodsreef Mines Limited, Barraba, Australia. 2. Senior Lecturer, Department of Chemical Engineering, Monash University, Vic, Australia. formerly Senior Research Officer, Research Department, ICI Australia Limited

Jan 1, 1986

By Andersson PO

Boliden Mineral AB Boliden Mineral AB operates nine mines in Northern and Central Sweden, producing zinc, lead and silver concentrates and copper and gold. Seven of these mines use cut and fill (C&F) mining with a total production of 2 Mtonnes of ore per year.

Jan 1, 1998

By E Rubio, N Morales

Currently, mine plans are optimised by using several criteria as objective functions, like profit, life-of-mine, concentration of some pollutants, mining costs, confidence level or ore resources, with consideration of constraints related to production rates, plant capacities and grades. Whilst this approach is successful in terms of producing high value production schedules, it uses a static opening sequence of the drawpoints and therefore the optimisation is made within the level of freedom left by the original opening schedule, and as a result it is far from the true optimal value of the project. This paper presents a model to optimise the sequence of drawpoint opening over a given time horizon. The emphasis is in the precedence constraints that are required to produce meaningful operational sequences considering the exploitation method (panel or block caving), physics considerations and logical rules. Further on, while it applies the standard approach of maximising net present value (NPV), it considers other targets for optimisation, like the robustness and constructability of the plans. Finally, it applies the model to real data to obtain feasible plans by means of this model. The first tests were done varying the production capacity of the mine.

Sep 26, 2011

By P Ireland, S Mitra, G Evans, A Wang, M M. Hoque

This work presents an experimental study of flow dynamics in a bubble column system (crosssection: 100 mm × 100 mm) using a non-intrusive optical technique with targeted application in a novel REFLUX™ Flotation Cell. The study had two aims – measurement of the bubble size distribution (BSD) and local energy dissipation rate in the system due to bubble motions over a low range of gas flux varied from 0.02 to 0.08 cm/s without impairing the visibility of the system. A central bubble plume was generated by injecting compressed air through a sintered glass distributor in quiescent liquid. Highspeed shadowgraphy imaging was performed to determine the BSD in the presence of surfactant (Sodium Dodecyl Sulfate (SDS) concentration ~ 10 ppm). The BSD exhibited a unimodal shape at different locations of the column for all gas flux cases. A non-intrusive particle image velocimetry (PIV) technique was used to quantify the flow field generated by the bubble motions, which was used to estimate the local energy dissipation rate. The local energy dissipation rate exhibited an increasing power-law dependency on the gas flux.

Aug 24, 2022

By D Matthews

With a brownfield project comes control integration challenges. The Khumani Iron Ore Mine’s second phase expansion posed a number of challenges as there was substantial brownfields work conducted. The fi rst phase was the compilation of the modifi ed process functional specifications for the project. The second phase was an audit on all of the operational sequences; this included a comparison between the SCADA sequences, sequential starts analysed from the historian data (with the potential for improvements made by the plant operators in manual start-ups) and what was proposed in the process functional specification. Differences, inclusions and missing equipment were highlighted. The third phase was the comparison of interlocking and control in the PLC with the updated process functional specification; this was done during the coding process. Running parallel to the three phases was the SCADA integration; tie-ins to the existing SCADA were conducted on maintenance days and shutdowns, in many instances with ‘dummy’ equipment to get the operational staff accustomed to the new interface. This paper details each of the phases, the success of this methodology as well as the pitfalls experienced.

Jul 11, 2011

By J Q. Shi, M Karakus, Y Liu

Predicting the spatial distribution of rock mass properties in cave mining is a critical challenge. In this study, we introduce a novel machine learning-based model to advance our comprehension of rock behaviour. This model specifically focuses on the spatial distribution of rock mass and mechanical properties, a crucial aspect of our understanding of rock mechanics. Our model is inspired by the recognition that neighbouring information serves as crucial prior knowledge for predicting the spatial distribution of these properties, wherein closer neighbours are likely to exhibit similar characteristics. To effectively capture and model these neighbour relationships, we design a neural network-based model to map the spatial locations within the data set into a new highdimensional space. Within this transformed space, we utilise Euclidean distance to identify N neighbours. Leveraging these neighbours, we introduce a straightforward yet highly effective approach—label propagation—to construct a graph that illustrates neighbour relationships. This graph not only facilitates the prediction of the spatial distribution of rock mass properties but also offers a measure of uncertainty for these predictions. We validate the proposed method using a real rock data set and showcase its efficacy in capturing intricate relationships and distributions within rock properties, enabling precise predictions across diverse spatial scales. Our results underscore the potential of machine learning-based approaches to revolutionise the field of rock mechanics, providing valuable insights applicable to geotechnical engineering, mining, and other sectors where an accurate understanding of rock properties is paramount. This model has direct practical implications, offering a new tool for geotechnical engineers and mining professionals to enhance their understanding and prediction of rock properties, thereby improving safety and efficiency in their operations.

Sep 1, 2024

By Mernagh T, Large R. R, Ryan C. G, Huston D. L

The Tennant Creek goldfield is one of the largest gold producing districts in Australia, and major deposits, including Gecko, Juno, Orlando, Peko, Warrego, Nobles Nob, Golden Forty, Argo, TC 8 and White Devil have produced more than four million ounces of gold over the past two decades. Gold-copper-bismuth mineralisation at Tennant Creek occurs in lenticular, ellipsoidal or pipe-like bodies of magnetite-hematite ironstones which are hosted in turbiditic sedimentary rocks of Proterozoic age (Large, 1975; Wedekind, Large and Williams, 1989; Le Messurier, Williams and Blake, 1990; Morrison, Donnellan and Hussey, 1992).

Jan 1, 1994

By I Mason, G Turner, J Hargreaves

One of the key objectives in production from any mine is the minimisation of ore loss and dilution. This can only be achieved when the distribution of ore within the mine is known. The distribution of ore is usually evaluated from a combination of drill hole information and underground mapping data. Three-dimensional models of the ore distribution are then constructed by interpolating grades, contact locations and confirming these estimates through mapping. While the interpolation procedure can incorporate an understanding of the local geological conditions, it is an approximation and thus susceptible to some degree of ore loss or dilution. Naturally, such problems increase in areas of sparse geologic information or greater geologic complexity. Borehole radar offers an approach to decrease the interpolative aspects of modelling by providing a continuous image of some ore contacts. Borehole radar works by building a two-dimensional image of an ore contact from radio waves bounced off the contact from closely spaced positions along a borehole. This image can be imported into Datamine (or a similar design package) and incorporated into geological models of a given ore block. The results of a trial survey from the Mariners nickel mine at Kambalda are presented to illustrate the improved level of detail and accuracy that can be achieved through the incorporation of borehole radar into orebody delineation practice. Once implemented on a large-scale this technique has the potential to greatly increase the cost-effectiveness of long hole stoping at Kambalda, through increased ore recovery and reduced dilution.

Jan 1, 2000