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By J Samosir, L A. Snyman

Northparkes is located 27 km north of the township of Parkes in central New South Wales, Australia. The operations consist of underground block cave mines and an ore processing plant that produces high-grade copper and gold concentrate. Production is currently sourced from the E48 Lift 1 block cave mine and open cut stockpiles. Mining commenced at Northparkes in 1994 as an open cut operation. Underground block cave mining began in 1997. Northparkes was the first mine in Australia to use the highly efficient block cave mining method, which relies on gravity and natural rock stresses to fragment the ore.An issue affecting production in 2011 was the stability of the E48 mine. A small portion of the drives on the extraction level began to deteriorate as the ground support system failed. The problem was temporarily fixed by stopping production in three extraction drives and tight filling selected areas within these drives (and drawpoints) with low-strength concrete. This action provided immediate support and stability whilst allowing time to investigate potential ground support remedies. From these investigations it was decided to use resin injection technology and additional ground support to stabilise the rock in the aforementioned extraction drives as the concrete plug was excavated in a controlled advance and sequence. This made the area safe and ensured the ongoing safe operation of the E48 mine. The redevelopment of one of these drives began late in 2011, with the remainder being progressively redeveloped over the next two years in order to maintain the extraction level stability.This paper looks at the strategies employed to safely re-open previously converged drawpoints and associated extraction drives that were subject to high abutment loading that was possibly associated with premature cave breakthrough.CITATION:Samosir, J and Snyman, L A, 2014. Redevelopment at Northparkes following significant drive closure, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 87–92 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By G J. Halstead, R C. Steinhaus

The True Pipe® in-line sampler was developed in an attempt to address the need for a mechanically reliable and correctly designed sampler to suit one-dimensional pressurised slurry pipelines, often found in metallurgical process plants but for which no reliable and representative sampling solution as yet exists.The design, whose operation is based on the principle of symmetry, is described by Dominique François-Bongarçon (2005) with the synchronous opening and closing of relevant valves. It representatively isolates portions of the particulate material stream at predetermined intervals for effective extraction of primary increments for subsequent sample compositing.Theory of Sampling applicable solutions have proven elusive in flowing pressurised particulate material streams, with various attempts to date not having formulated a viable, mechanically reliable and acceptable design.Compliance to sampling theory is critical, and a number of tests were conducted where certain operating parameters were altered to determine their influence and sensitivity on sampling representativeness.The results of the initial series of tests performed on a carefully designed rig are presented, with additional work discussed for necessary investigation in the near future.Getting closer to a robust, economic and correct design for this challenging application in the minerals industry may now not be that far away. Plant management staff will see improved metallurgical mineral balances around their process plants and significantly reduced sampling discrepancies, particularly in tailings applications. Improved quality control is now possible where, due to plant head room constraints, classical cross stream sampling methods cannot be employed.CITATION:Steinhaus, R C and Halstead, G J, 2014. True pipe sampler – a correct design utilising the principle of symmetry in pressurised slurry particulate streams, in Proceedings Sampling 2014 , pp 127–134 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 29, 2014

By King D, Dickinson S. B, Matheson R. S

Commencing in 1956, Rio TInto Australian Exploration Pty Limited in association with Electrolytic Zinc Co of Australasia, Limited, has been carrying out a mineral prospecting program in North-West Tasmania over an area of about 4000 square miles.The program has comprised extensive airborne geophysical surveys, detailed geological mapping, ground geophysical and geochemical investigations. Out of the wealth of new data, and the examination of previous records, has emerged a new structural concept of regional ore control and distribution in North-West Tasmania. This roncept stems from the discovery of an ancient 'fossil' rift valley (graben), named the Owen Rift Valley, along which are located the major mines of the area and numerous well-known prospects. The known mines and prospects from north to south include Mt Bischoff (tin); the Pinnacles (zinc, lead, ropper); the Chester (pyrites); Rosebery-Hercules (lead, zinc, ropper, silver, gold); Mt Tyndall (lead, ropper, zinc); Comstock and Tasman (copper, lead, zinc); Mt Lyell (copper, pyrites, gold); Mt Jukes and Mt Darwin (ropper). The identification of the West Coast (Owen Conglomerate) Range as a fossil rift valley is due to Or B Campana, who carried out extensive geological mapping and interpretation work, and who, with S B Dickinson, are the senior authors of this paper.S B Dickinson, who introduced B Campana to the geological problems of West Tasmania, had previously investigated the Mt Lyell and Rosebery mining fIeld, to which reference is made in this work.D King assisted in the regional mapping and in providing numerous data on the mineral distribution of the area.R S Matheson rontributed to the fmdings on ore emplacement and rontrol in the discussions held on this subject. They are accordingly included as joint authors of this paper.Credit is also due to E McCarthy, who interpreted the geophysical results, and to J H Rattigan, who compiled the preliminary geological maps from published documents and by photo-geological methods.G Hall and V H Cottle, of the Electrolytic Zinc Co in Rosebery, provided invaluable geological data and suggestions in the course of the survey, and made a constructive criticism of the manuscript of this work. The airborne geophysical survey carried out by the Adastra-Hunting Geophysics Ltd company, furnished useful data which substantiated many of the fIndings on the stratigraphic and structural relationship. The Mines Department of Tasmania and S W Carey, Professor of Geology at the University of Tasmania, were instrumental in initiating the regional survey and provided the published and unpublished geological literature on the area.The authors also wish to acknowledge the invaluable assistance received from the Mt Lyell Mining and Railway Co in Queenstown, which made available the more recent geological and mining documents rompiled by M L Wade and M Solomon.

Jan 1, 1994

By S M. Arndt, D Tyler, F Reusch

Although significant advances have been made in understanding the mechanics of pit slopes, numerical modelling hasnÆt significantly impacted on the reliability of the design process. It is well known that legacy modelling approaches donÆt simulate large slopes well. In recent times, the emergence of very large finite element (FE) models with more than ten million degrees of freedom and the ability to simulate a large number of discrete structures, has allowed a step change in the simulation precision for slopes. The model size allows global and local effects to be realistically simulated in one model for the first time and the process can be better integrated into normal open pit slope engineering processes. Some examples of simulation of very large open pits are shown that demonstrate the challenges and some recent advances in modelling large slope behaviour. Significant limitations in the current measurement and observation regimes of open pits have been identified.

Jan 1, 2007

By T Elkington, A Finch

The theory of constraints (TOC) is a business improvement method that focuses on exploiting a business’s bottleneck to deliver the highest possible profit. Early applications were mostly in the manufacturing industry; however, the theory in itself is completely generic and has now been applied widely in other industries such as services, retail, software and distribution, amongst others. The intent of the approach is attractive – it focuses on the ‘silver bullet’ rather than ‘death by a hundred projects’, and it focuses on growth rather than cost cutting. Application within the mining industry has been limited to date, although there are a few applications emerging. This paper discusses how TOC can be applied to maximise value during the project planning phase and how to maximise profits when the mine is operational. The paper uses two case studies to illustrate the approach. Case study 1 uses the approach to improve tactical mine planning, which delivers an increase in revenue of 58 per cent. The second case study is a strategic mine planning example that delivers an increase in value of 77 per cent.CITATION:Finch, A and Elkington, T, 2014. Application of the theory of constraints to strategic and tactical mine planning, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014 , pp 129–136 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

By M Saghaeian, V Sheikhzadeh, R Hejazi

Mining dilution is one of the most important factors affecting the economy of mining projects. Instead of quantifying dilution in mining studies, it is common to assume a general dilution such as 5 per cent for massive deposits. Dilution increases the operating costs in the plant by increasing the tonnage of material to be milled. It prolongs the mine life by reducing plant’s effective capacity. It also reduces the feed grade. In most cases, lower feed grade means lower plant recovery. Dilution also increases the cut-off grade, which in turn reduces the overall ore utilisation of a mine. In this study has been investigated applying pre-concentration by dry magnetic separation for decreasing of dilution impact on reserve estimation and open pit design in low-grade iron ore mine. Based on the preliminary open pit design and assumption 3 per cent as dilution factor, the mineable ore in life-of-mine (measured + indicated) has been estimated with Fe = 25 per cent, SiO2 = 49.7 per cent. Based on the experimental test work on the ore, by dry low intensity magnetic separation of dry HPGR product grinding circuit, it is possible to remove diluted waste material and liberated gangue before concentrate plant, so that around 34 per cent rejected and Fe grade increase from 25 per cent to 33 per cent and by weight recovery 66 per cent. The results of the test work showed that this methodology could decrease largely the impact of dilution in the feed to the plant. It also slightly effect on the reducing of dilution factor impact for open pit design and optimisation and leads to increase the mineable tonnage in the low-grade magnetite iron ore mine.

Aug 24, 2022

By M Darvall

Magnetite ore blending has yielded signifi cant performance improvements in OneSteel’s magnetite concentrator. The magnetite concentrator beneficiates magnetite ore from the Iron Magnet Deposit and produces concentrate, which is pelletised, then fed to the OneSteel Whyalla blast furnace. Concentrator feed variability severely detracts from the concentrator’s performance, affecting both concentrate yield and grade, which impacts on all downstream processing costs.A coordinated approach has integrated mine planning, geological modelling and grade control, to minimise concentrator feed variability, through effective ore blending throughout the mining and stockpiling process.Mine planning personnel design shots that extend the full width of the orebody and hence across the stratigraphic profi le. Based on geological information contained in block-outs and in consultation with Geology, the Grade Control team allocates material to each primary stockpile, potentially from every stratigraphic domane in the orebody. This ensures primary stockpiles are designed with maximum practical homogeneity and consistency.Using only primary movement, the allocated ore is stockpiled in a layer-cake fashion. The ore is pimple dumped across the width of the stockpile footprint and on completion of a layer, it is dozed flat with an access ramp that allows dumping to commence on the next lift. The primary stockpiles are reclaimed normal to build direction and the magnetite is crushed, all in, to a concentrator feed stockpile.The ore is sampled at the crusher from a falling stream cut. These assay data, are used for benchmarking and control charting the grade and variability of concentrator feed stockpiles. The concentrator feed stockpiles have demonstrated a statistically signifi cant reduction of within pile variation, between pile variation and pile to pile variation, primarily attributable to the development of ore blending. The concentrator has seen sustained, improved performance as a direct result, which translates into lower concentrate cost per tonne and improved yield and quality.

Jul 11, 2011

By G Collecutt, T O’Beirne, D Humphreys, J Greenwood

Much of our knowledge of the behaviour of underground coal dust explosions has been derived from less than full-scale experimental explosions in facilities as small as 0.25 m diameter pipes. Although a substantial body of research has been undertaken in larger galleries approaching the size of full-scale modern mine roadways, there are still questions regarding the scaling of results to full-sized roadways in modern coalmines. Questions also surround the issue of comparing or scaling results between smooth and rough walled galleries, round and rectangular galleries and galleries with differing wall thermal properties due to different materials of construction.This paper will examine the influence of gallery size, cross-section area and wall roughness and thermal properties upon the characteristics of a coal dust explosion. Data from past explosion research will be examined and assessed for its application to the problem along with theoretical considerations for these factors.Recommendations on the design and minimum appropriate size of explosion galleries for assessing the performance of explosion inerting strategies, passive and active explosion barrier performance and determination of appropriate pressure ratings for ventilation structures will be made.CITATION:Humphreys, D, Collecutt, G, Greenwood, J and O’Beirne, T, 2015. The impact of facility construction and scale on the characteristics of experimental coal dust explosions, in Proceedings The Australian Mine Ventilation Conference, pp 301–308 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

By B Vietnieks, N Widmer, L White, E Tata, J Natukunda, D C. Ilouga, J P. Tyler

The Republic of Uganda aims to exploit its’ significant, un-developed iron ore resources to supply the required raw material for developing its’ iron and steel industry across all the stages of the supply chain. Large prospects of iron ore exists in Uganda in the eastern (Tororo) regions and southwestern (Kisoro-Kabale) regions of the country. The Kisoro-Kabale iron ore projects covers mineralisation in hematitic banded iron formation (itabirite) in the north-eastern Congo-Tanzania Craton; covering ten Iron ore prospects. The prospects include Kamena, Karukara, Nyamiringa, Kyanyamuzinda, Rugando, Katagata, Rwengongo, Kijuguta, Kihumuro and Katuna. High-grade hematite ore prospects in south-western Uganda have known grades ranging from 55 per cent to 68 per cent iron ore content with an exploration target estimated at over 500 million tonne (Mt). Small scale production of iron ore from the south-western regions provide raw material to existing steelmaking and direct reduction iron ore plants located in the Jinja and Iganga districts of eastern Uganda. Large quantities of iron ore and other steelmaking raw material, however, are required to be imported into Uganda due to the limited exploration and development of their own iron ore mining operations. A joint collaboration between the European Union (EU), the Department of the Geological Survey and Mines (DGSM), Ugandan Ministry of Mines in partnership with Australian drilling and mining consultancies, ADT Africa and Kalem Group as a EU funded project was undertaken during November 2022 and September 2023. Exploration and evaluation of the ten iron ore prospects in south-western Uganda was undertaken through geological mapping, drilling, assaying, and technical studies with the view to attract investment for the development of Uganda iron ore mining and steelmaking industry. The collaboration developed mineral exploration policy, guidelines and standards, an iron ore exploration manual, a geological data management policy, and to support the sustainable development of iron ore mining in Uganda through building the capacity of local Ugandan geology and mining personnel through the transfer of knowledge and expertise from experienced iron ore experts. The quantification of these resources is an important first step in assessing their economic potential and attracting mining investors. This paper presents an overview of the investigation program and the preliminary results as an important first step in attracting mining investors to this exciting new iron ore province.

Sep 18, 2023

By Q Yang

This paper describes the design and construction of three 7.2 m span access ramp-tunnels to the three level underground car park of the newly redeveloped Top Ryde City Shopping Centre in northern Sydney. The tunnels were to be excavated without significant impact on the overlying Devlin Street, one of the busiest arterial roads in the Sydney metropolitan area and a major link in the Sydney road network. The interpretation of the geological conditions indicated that the tunnels would be driven in a formation of heavily jointed, extremely weathered to fresh Triassic Ashfield shale with some structural features such as dyke, fault and shear zones identified in the available boreholes logs. Both empirical and numerical methods were used to design the tunnels and to predict the ground surface settlements. The design solution, which was influenced by the relatively small scale nature of the work and the current demands on the tunnel construction market, included presupport, initial support and permanent steel fibre reinforced shotcrete (SFRS) lining. The interactions of the driven portals with cut and cover sections and the proposed deep excavation of the new shopping centre were considered at the design development stage and in the construction phase to ensure the safety of the live road. The tunnels have been successfully constructed and are now operational.

Mar 8, 2011

By C Dowding, C Aimone-Martin, P Abeel

This paper presents measurement and analysis of the dynamic response of a five-storey building to very high frequency excitation (>100 Hz) from blasting vibrations originating from a contiguous excavation of rock. Velocity response measurements in the rock and on the structure were employed to calculate the time-correlated dynamic displacement response of the building to blasting. Time-correlated structure response measurements are needed to advance the understanding of the response of urban structures to high-frequency excitation. Current regulations and understanding are based upon measurements of the response of one- to two-storey residential structures by 10 to 40 Hz excitation. The extension of these observations to taller structures when excited by high-frequency excitation needs to be investigated further.Measurements show that the amplification patterns at the ground level and top of the structure match or are lower than that observed by the US Bureau of Mines (Siskind et al, 1980) for the shorter residential structures. They decrease with increasing peak particle velocity. From the measurements, the global transverse shear strains found by differentiating ground floor and top displacements were calculated to be 12 µstrains. Time-correlated bottom and top of structure displacements show that building response may be more reflective of wave propagation up the structure than whole-structure inter-storey drift.In addition, a 3D model was used to compare computed displacements and strains to measured results. Modelled responses varied considerably, both in magnitude and location of the maximum strain. No conclusion can be made regarding the best 3D model to employ to simulate building response. More data such as motions measured at many points in the structure are needed. Maximum inter-storey transverse shear strains calculated with the model were found through the acceleration excitation and were less than 12 µstrains for 37 mm/s rock motion excitation. The inter-storey transverse shear strains calculated with rock displacement input were less than that found with the acceleration excitation.CITATION:Dowding, C, Aimone-Martin, C and Abeel, P, 2015. Measured and modelled response of a multistory, urban structure to high-frequency blasting excitation, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 211–220 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By K Higuchi, K Saito, O Ishiyama

Iron ore in Australia is predicted to increase in its phosphorus content in the near future, which is detrimental to properties of steel product. Steelmakers are concerned by the content of phosphorus in iron ore will exceed limits for steelmaking and increase the converter slag ratio to molten steel, which will finally lead to a decline in competitiveness in high-grade steel production. In this paper, fundamental development of a dephosphorisation technique by reduction gasification is considered. Basic reduction examination was carried out using Australian and a synthetic model iron ore sample with phosphorus compound reagent, varying reaction time and composition of substances to find out suitable process condition for dephosphorisation. With successful lowering of phosphorus concentrations by gasification reduction of the iron ores, dephosphorisation was assumed and further elucidation works were carried out. More than 10 mass per cent of dephosphorisation ratio is obtained from Australian iron ore through batch-type 25 g furnace experiment using hydrogen as a part of reducible mixed gas. Lowering of phosphorus content occurred preferentially either in wustite or in another reducing zones, suggesting a relationship between reducing conditions to efficient dephosphorisation of iron ores. Another result of the fundamental experiment using a model sample with reagent is different dephosphorisation occurred with different reagents contributing to with unified reduction model for phosphorus, providing positive possibility for comparative evaluation, even if new morphologies of phosphorus in iron ore are clarified in future. According to these approaches, it is important to reduce iron ore efficiently and to avoid gasified phosphorus retaining and reattaching to adjacent iron ore particle at the same time. A kiln-type furnace is suggested to overcome previous technical issue, and additional experiments using larger rotating furnace were carried out for verification.

Sep 18, 2023

By G M. Mudd

The growing popularity of platinum and platinum group metals (or PGMs, including palladium, rhodium and others) for a wide range of applications leads to some interesting issues for mining and sustainability. The uses for PGMs includes catalytic converters for air pollution control in vehicles, growing jewellery use, catalysts for various purposes (especially petroleum and chemicals processing), hydrogen fuel cells and many others. Given the growing importance of most of these PGM uses in more sustainable technologies or in making industrial processes more efficient, it is critical to understand the complex sustainability issues which surround platinum and PGMs. At present, South Africa is the dominant PGMs producer and holds about 88 per cent of estimated global resources, with important but relatively minor production and resources in Zimbabwe, Russia, Canada and the United States. Given the concentrated location of PGM resources, what are the likely trends in PGM mining with respect to environmental sustainability? That is, what are the costs in terms of energy, pollution, greenhouse gas emissions, water, land use impacts, social impacts, economic aspects associated with this globally important industry? This paper compiles and analyses a range of data on platinum-PGM mining, focusing primarily on South Africa. It synthesises a unique combination of data which relates typical production aspects such as ore grade and scale with sustainability aspects such as greenhouse, energy and water costs. The findings are critical in understanding the debate about the increasing environmental and social costs of some materials and technologies which are considered crucial for sustainable industries based on PGMs. Overall, the paper represents a valuable insight into the platinum-PGM sector, providing a range of useful data for understanding the environmental sustainability of this particular group of precious metals.

Jan 1, 2009

By J T. Sharp, M A. Styler, D McGowan, P W. Mayne

Static liquefaction is a geotechnical hazard in mine tailings facilities. Soils that are contractive in shear are susceptible to static liquefaction. Tailings facilities are dynamic structures, typically growing in height each year. Dilative tailings may become contractive under increased effective stress. In this paper we show that Cone Penetration Test (CPT) data can be used to estimate the future state of in-place tailings under changes in effective stress. Susceptibility to static liquefaction is typically evaluated with the CPT by using a clean-sand equivalent normalized cone tip resistance (Qtn,cs) or by estimating the state parameter (?). An alternative approach is to evaluate the soil-state using the yield-stress-ratio (YSR = ?’y/?’v0). If the YSR equals one it is on the normal consolidation line and the soil-state is contractive. YSR values greater than three are typically dense of the critical state line (CSL) and the soil-state is dilative. In this paper we review how to calculate Qtn,cs, ?, and ?’y; and how the YSR can be used to screen for contractive soil behaviour. Unlike Qtn,cs and ?, it is very simple to estimate how the YSR will change due to an increase in overburden stress. This YSR approach was evaluated at three locations that saw increases in overburden of 10 m, 20 m, and 25 m. We show that the ?’y calculations are consistent and the increase in effective stress moves the soil state towards looser soil states. CITATION:Styler, M A, Mayne, P W, McGowan, D and Sharp, J T, 2018. Predicting changes in static liquefaction susceptibility using cone penetration test results, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 317–332 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

By Y Zhu, W Liang, P Knights

In recent years, Chinese companies have invested billions in Australian mineral exploration, development and processing. In 2008 - 2009 alone, the Foreign Investment Review Board approved $26.4 B of investment. Much of this investment has been by merger and acquisition (M&A) of Australian resources companies. This paper sets out to investigate how Australian CEOs perceive the cultural and institutional challenges in operating Australia mining companies recently acquired by Chinese interests. HofstedeÆs cultural dimensions and institutional theory from management science were used to develop a structured questionnaire, which was subsequently used to conduct telephone interview of the CEOs of six recently acquired mining companies. Analysis of the survey results indicated that, in all cases, few changes were made to the operational management of the Australian companies post-M&A. The three major benefits for Australian companies as a result of the M&A are the ability to; access long-term debt at lower cost; secure finance for growth plans in financially volatile times; and maintain existing management structures. Some perceived negatives involved longer and more convoluted decision-making as a result of Chinese state approval required for investment decisions. The study identified building æGuanxiÆ and an aversion to losing æfaceÆ as important cultural learnings for Australian CEOs. Maintaining effective communications is regarded as key for successful cultural integration.CITATION:Liang, W, Zhu, Y and Knights, P, 2012. Cultural challenges in Chinese/Australian mining mergers and acquisitions - A CEOÆs perspective, in Proceedings International Mine Management 2012, pp 251-260 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 20, 2012

By S Padekar, C Tapia, D Likhachev, S Harlikar, D Sapkale

In the quest to access valuable critical minerals, humankind is expanding the frontier into extreme environments like space and deep-sea mining. These ambitious enterprises involve considerable costs and lengthy development cycles to ensure the robustness of mining systems in the face of the harshest conditions and unforeseen challenges. Unfortunately, obtaining information from these unexplored territories is complicated. Data is often scarce, incomplete or impossible to obtain until equipment is deployed, leaving engineers facing many uncertainties throughout the design, testing, production and preparation of such missions. Despite these challenges, these extreme environments operate under consistent physical and chemical principles that can be faithfully digitally replicated. However, unexplored areas and dynamic systems like weather and geology continue to carry uncertainties. While eliminating uncertainties remains elusive, Digital Twins offers a means of robust risk management tool. These virtual replicas can excel in simulating extreme conditions and unexpected events, helping optimise and validate mining system designs tailored for such hostile environments. This study takes inspiration from the Mars Science Laboratory (MSL) Curiosity Rover’s wheel damage rate to develop a Multiphysics Modelling and Virtual Motion Simulation (MMVMS) system. Using advanced Generative Design, this MMVMS system refines the MSL’s design, simulates component and system performance, and assesses the risk of premature damage while operating on Mars. Additionally, MMVMS integrates cutting-edge CAD design technologies from aerospace and manufacturing to realistically recreate the Martian environment and a detailed representation of MSL, allowing mobility verification and validation simulation to test different components in terms of materials, design, weight, power and, therefore, cost. The research highlights the precision of MMVMS in replicating extreme conditions, simulating and evaluating internal and external variables influencing the entire system (Rover) in real-time, and predicting movements, failures, and premature damage. This sophisticated Digital Twin technology, showcased in this research, holds promise not only for space missions but also to be adapted for terrestrial and deep-sea mining operations.

Sep 1, 2024

By R Moreby, J Kok, L van den Berg

The high production rates achieved from mass mining methods such as block caving, sublevel caving and longwall mining require large conveyor belts, trucking loops (diesel/electrical) and rail systems for ore handling. However, the ore handling systems used in mass mines introduce a significant amount of heat into the overall ventilation system, which may be problematic at depth or in mines located in hot climates.In particular, the heat load from a conveyor system is not always well understood and consists of various components, including frictional heat from idlers, heat from electrical motors, heat from the drive train and heat from broken rock transported on the conveyor system. This paper presents results from a study that investigated the heat introduced to the ventilation air from a large conveyor system. The conveyor system transports ore with a maximum virgin rock temperature of 41°C from a depth of over 1 km. Air, belt and rock temperatures were measured in the conveyor system to evaluate the distribution of heat loads.CITATION:van den Berg, L, Moreby, R and Kok, J, 2015. Heat load estimation from conveyor systems in mass mines, in Proceedings The Australian Mine Ventilation Conference, pp 63–70 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

By Allnutt S. L, Radojkovic A. M

Century, a major shale hosted zinc deposit in the Riversleigh Fold Zone of northwest Queensland's Mount Isa Basin, was discovered by CRA Exploration in 1989. A total of 322 drill holes, completed by the end of 1992, define a resource of 118 Mt of mineralisation averaging 10.2 per cent zinc, 1.5 per cent lead and 36 grams per tonne silver. Mineralisation is developed in the upper portion of Lawn Hill Formation Unit 4 (Pmh4). The intersection of the Termite Range and Little Range Faults, major regional structures, may have been important in controlling mineralisation development. Three listric normal faults, and an unconformity between Proterozoic rocks hosting mineralisation and overlying Cambrian carbonates, divide the deposit into three distinct blocks. The deposit is essentially blind, outcropping in only two places. The deposit is characterised by an extremely simple sulphide mineral assemblage, sphalerite being the most common sulphide phase. Pyrite, the most common phase in many other shale-hosted zinc-lead deposits, accounts for only five per cent of all sulphides present. Siderite is the principal non-sulphide phase present. Both sphalerite and galena have near stoichiometric compositions. Sulphides are confined to carbonaceous shale horizons. Intervening siltstones are essentially barren. Shale and siltstone beds forming the mineralised sequence can be correlated across the entire deposit area. Systematic grade variation occurs within each mineralised shale bed. Although sulphide laminae parallel primary lithologic layering, the point of most intense mineralisation development transgresses stratigraphy. Bituminous material is intimately associated with sulphide mineralisation.

Jan 1, 1993

By J Savage, A Crawford, M Doyle, N McNaughton, T G. Blenkinsop

Area selection criteria for gold exploration have historically highlighted the low prospectivity of high-metamorphic grade terranes relative to regions with lower metamorphic grades. The Tropicana gold project, Western Australia, is a rare example of a major greenfields gold discovery in Archean mid-amphibolite to granulite-facies gneissic rocks that have experienced widespread recrystallisation and partial melting.The project, located on the tectonically reworked eastern margin of the Yilgarn Craton, is part of the Tropicana Joint Venture, which is 70 per cent owned by AngloGold Ashanti Australia (manager) and 30 per cent by Independence Group NL. Construction of the mine commenced in the June quarter of 2011 and first gold pour from open pit mining is anticipated in the December quarter of 2013. The approved project will have a ten-year mine life and in the first three years of operation, gold production will be between 470 000 - 490 000 oz/a at a cash cost of A$590 - A$630/oz.Reserves as at 31 December 2011 total 56.4 Mt grading 2.16 g/t for 3.91 Moz of gold. The mineral resource, as of 30 December 2012, has grown to 7.89 Moz of contained gold, including Inferred Resources of 11.9 Mt at 2.83 g/t for 1.08 Moz.Economic gold mineralisation post-dates peak metamorphism and is interpreted as younger in age (ca. 2500 Ma) than other gold deposits in the Yilgarn Craton on the basis of structural and geochronological constraints. Mineralisation is genetically related to an imbricate thrust stack that records a prolonged history of reactivation during the Proterozoic era. Gold mineralisation formed from higher temperature (>350¦C) silica-undersaturated fluids that preferentially migrated though a favourable intensely potassium metasomatised zone. Permeability created during brittle fragmentation was accompanied by replacement of mafic metamorphic minerals, and synchronous partitioning of strain into pervasively biotite-sericite-pyrite-altered stylolites and shear planes that bound more competent lithons.CITATION:Doyle, M, Savage, J, Blenkinsop, T G, Crawford, A and McNaughton, N, 2013. Tropicana - unravelling the complexity of a +6 million ounce gold deposit hosted in granulite facies metamorphic rocks, in Proceedings World Gold 2013 , pp 87-94 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By A Rantala, C Cruickshank, I Muzinda, O Haavisto, J Timperi

The production at First Quantum Minerals’ (FQM) Kevitsa Mine, located in northern Finland, commenced during the second quarter of 2012. Presently, the mine processes approximately five and half million tonnes of ore annually, producing nickel, copper and platinum group metal (PGM) concentrates. In order to support fast production ramp-up and optimise the performance of flotation thereafter, an extensive advanced flotation control solution was implemented by Outotec in collaboration with FQM Kevitsa.In addition to basic process instrumentation and process control, each of the 14 Outotec 300 m3 and another 26 cells, ranging from 20–160 m3, have been equipped with state-of-the-art systems providing froth image analysis and automatic froth speed control. Also, the flotation cell levels are stabilised with advanced feed-forward level control.The online analyser provides key feedback information of the process performance for the advanced process control (APC) system. Based on this information, APC system defines grades and recoveries according to rules defined by Kevitsa process metallurgists. This system executes the control strategies for optimising the production of concentrates.Throughout the implementation and support phases, specific and intensive attention was paid to ensure plant personnel gained full understanding of interacting with the system and how to incorporate their process experience and skills to optimise the APC strategy. This level of expertise is also a valuable asset in understanding the APC system’s contribution to the overall performance of the plant as well as providing the ability and confidence to define key performance indicators used for continuous assessment. The experiences and results from site achieved so far are discussed in this paper.CITATION:Rantala, A, Muzinda, I, Timperi, J, Cruickshank, C and Haavisto, O, 2014. Implementation of advanced flotation control at First Quantum Minerals’ Kevitsa mine, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 369–378 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014