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By B Crompton, A Berghorst, G Knox

Laboratory-based dynamic testing provides an invaluable tool in the development of rock bolts for use in highly stressed, burst prone rock masses. While in most cases the laboratory-based test method is not a direct comparison to an in-situ installation due to the purely axial loading and variations in boundary conditions, it does provide an indication of the performance of the tendon system under dynamic loading. The aim of the research described in this paper is to provide an understanding of the effect of the impact velocity of the impact mass during a laboratory-based dynamic test. Understanding the effect of boundary conditions of laboratory testing will improve Geotechnical Engineers understanding of the performance in an in-situ installation. In addition, due to the limited number of dynamic test facilities, an understanding of the effects of the boundary conditions will aid in the comparison of test results for different products from different test facilities. The research was conducted using an impact tester, whereby a known mass is raised to a known height defining the kinetic energy and velocity of the mass at the point of impact with the test sample after release. The impact velocity was varied between 2.7 m/s and 5.4 m/s, while the kinetic energy of the mass was maintained at 11.5 kJ. While a correlation between the impact velocity and strain rate of the system tested was established, due to the properties of the system tested, the range of impact velocity on which dynamic tests were conducted was insufficient to result in a considerable change in the average impact load, the cumulative proximal displacement and the cumulative maximum energy absorbed over multiple impulse. However, due to the reduction in the momentum of the impact mass the impact duration and displacement during each impulse in the series of impulses reduced. CITATION:Knox, G, Berghorst, A and Crompton, B, 2018. The relationship between the magnitude of impact velocity per impulse and cumulative absorbed energy capacity of a rock bolt, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 160–169 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By A Tawadrous, D S. Preece

Cave mining is of interest to the mining community as it offers a chance to extract large, deep orebodies with low operating costs and high production rates. It allows for extracting large low-grade orebodies, which may not have previously been considered for mining. Cave mining is done either top down (ie sublevel caving) or bottom up (ie block/panel caving). Both approaches rely on gravity, stresses and weakness of the rock to fracture and achieve a controlled collapse.Block caving starts at the base of the orebody. It progresses upward and across through continuous collapse of the roof. To achieve this, a critical hydraulic radius must be exceeded. This is accomplished by blasting drawbells, through which the caved ore passes to the production level. An entire level above the drawbells (undercut level) is excavated to help initiate the cave. The undercut level ensures the connection between drawbells and achievement of the required hydraulic radius.Conventionally, drawbells are generated by drilling and blasting several times from the production level as well as the undercut level. Mucking between each shot is required to generate enough void space for the rock to swell. The need for several blasts necessitates some downtime between each blast. Also, the cost of developing and maintaining the undercut level can constitute up to 35 per cent of the cost of mining the panel.A new blasting technique was developed to create the drawbells in a single blast from the production level. The technique ensures the connection of the drawbell to the neighbouring ones, thus, the critical hydraulic radius is reached and propagation of the cave achieved without the need for the undercut level. The technique has the potential to reduce the capital cost of a block caving operation, increase its feasibility and reduce time to reach the ore and consequently the payback period. This paper presents the modelling of a traditional drawbell excavation process, the philosophy of the developed technique, the modelling of that new design and its implementation.CITATION:Tawadrous, A and Preece, D S, 2015. A novel blasting technique to create drawbells and eliminate the undercut level in block cave mining, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 617–624 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By I Gipps

Each of us has a vision of what the future mine will be and, generally, these visions have many similarities and some differences. One of the major discrepancies in visions of the future mine is not the ultimate goal but the path to achieve it. Many of the future concepts require a radical re-thinking of how things are and will be done yet. So how do we reach this visionary future mine? We need a path that satisfies both our future aspirations of a high tech gee-whiz operated from our iPads and the unfortunately mundane approach that says ‘we must know the method works, ie nothing new’.This paper explores how, within a research based organisation, we firstly set our ultimate goal and then divide the path into realistic technology development chunks that would appeal to mining companies to progress within their organisational constraints. Through examples, such as, automated LHDs, communications systems, surveying and localisation, rock cutting and geological sensing, we illustrate how this path will get us from the here and now to the out there future.This paper also demonstrates CSIRO’s short, medium and long-term research in many of the areas needed to create the Future Mine: mining methods, automation and remote control, mine communications, mapping and mission planning, geological sensing and, importantly, human-system integration, which examines how to effectively present data as information to operators and supervisors in an intelligent and useful manner.

Nov 22, 2011

By M J. Noy

The automated measurement of rock fragmentation particle size distribution in the muck during muck excavation has been developing over the last 16 years. The introduction of stereo camera imaging of the muck has provided improved automated particle segmentation for image-based measurement algorithms. Recently, a new vision system processing algorithm has been developed. The inclusion of 2D texture in the analysis has provided a significant improvement in the definition of the finer size fractions, which has resulted in the automated analysis no longer requiring calibration.The previous stereo vision system algorithm required analysis calibration to account for poor ‘small particle’ definition in the 3D surface profile. This was because of the depth perception limitations of the stereo camera system at greater than 8 m. The new algorithm has been implemented on a number of shovel-installed vision systems, and the algorithm’s performance in automated analysis has been assessed against a diligent manual analysis of the same fragmentation images. The new algorithm provides improved distribution resolution and accuracy.CITATION:Noy, M J, 2015. Evaluation of a new vision system algorithm for automated fragmentation measurement from a shovel, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 721–726 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By Ciminelli VST

Thiourea leaching has been applied to a refractory gold concentrate previously treated by bacterial oxidation. Following the bio-oxidation, gold has been leached in acidic thiourea solutions, under different pH(1 - 2.4), thiourea concentrations (2 - 15 g/1), ferric ion concentrations (0.04 - 3 g/1) and temperatures (298 - 333 K). Through this procedure, it was possible to increase gold extraction from 40 to 77 per cent. The increase in temperature raised gold extraction and reduced reagent consumption. Sodium sulphite addition was also very effective in lowering thiourea consumption. Staged leaching operations with interstage acid washing and carbon-in-leach experiments were tested, in an attempt to increase gold extraction. The results of thiourea leaching were compared with those obtained with cyanidation.

Jan 1, 1993

Kidston Gold Mines Limited (70 per cent Placer Pacific and 30 per cent Public Shareholders) has been mining the Wises Hill Pit since late-1984. The Wises Hill Deposit is a large low grade gold deposit and as such is highly sensitive to economic parameters. The uniformity of the orebody has allowed a bulk mining method to be used, with minimal dilution. Total reserves defined to-date are 64 160 OOOT at a grade of 1.60 g/t gold. Mineable reserves remaining as of January 1992 are 36 357 OOOT at a grade of 1.28 g/t gold.Mining investigations to reduce the impact of lower gold prices, the effect of decreasing headgrade and increasing mining costs have focused on wall steepening.

Jan 1, 1992

By P McCarthy

The relatively new field of geo-metallurgy promises to improve the predictability of mill feed quality and enhance processing outcomes. However, it is subject to the same limitations as the prediction of grade using geostatistics and has additional limitations due to the spatial distribution of the variations being measured and the sample sizes required. Schedules based on geo-metallurgical models will, in turn, be subject to variations arising from geological control and practical mining constraints.This paper discusses the key drivers of variations in mill feed quality and quantity from a mining perspective. It concludes that geo-metallurgical modelling addresses only one aspect of the problem. A case study is provided to illustrate poor predictability of metallurgical performance even with very detailed geological data.

Aug 8, 2011

By J Taylor, A Dubowik

To increase the efficiency and improve the quality of diamond drilling at Olympic Dam, mine geologists have adapted and modified common practices in order to overcome the challenges imposed by such a unique environment. Mine geologists have to take into account both the complex geology during the diamond drill hole design phase, as well as incorporating diamond drilling into the larger-scale scheduling process already employed at Olympic Dam. This study seeks to explore how such modifications have evolved over time.The geology of Olympic Dam influences the design process of diamond drill holes, particularly due to the variation of lithology and alteration, as well as the presence of magnetite and major structures within the orebody. Exclusion zones are used to manage interactions with existing and planned mining activities, and their size is dependent upon the geology of the area. Specific deviation checks are used to monitor the deviation of diamond drill holes with respect to these?zones.The highly interactive environment of Olympic Dam requires unique planning for diamond drilling, resulting in the production and implementation of both long- and short-term schedules. Long-term schedules are targeted at determining drilling locations and ensuring drilling is completed prior to stope planning, while short-term schedules aid in enabling access to ensure timely set-up of drill sites. Estimated drilling rates, determined by expected lithologies and historical data, feed into the short-term schedule to assist in managing the operation and minimising the downtime of diamond drill rigs. A mine geologist is appointed as a diamond drill coordinator to organise and manage diamond drilling at a scheduling and operational level, streamlining the entire process.Analysis of historical data shows a strong correlation between implementation of the aforementioned practices and improved drilling rates. This study shows the importance of adapting universal tasks to particular environments and circumstances. Mine geologists at Olympic Dam continue to acquire knowledge to further improve the modified drilling practices as operational requirements, production pressures and economic factors change.CITATION:Taylor, J and Dubowik, A, 2014. The evolution of diamond drilling practices at Olympic Dam, in Proceedings Ninth International Mining Geology Conference 2014 , pp 271–280 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

By T Leidich, M Van Zyl, H Lacy

Mining ‘as usual’, until the most recent decades has resulted in limited landform planning and a general lack of mine waste landform design. Material characterisation, mine planning and dedicated professionals undertaking these tasks were rarely available or in place at the majority of mines. This has led to landform instability, erosion, sediment and poor quality water emanating from mine landforms. In many cases rehabilitation and reclamation failed and these sites have ‘landform features’ that are difficult to relinquish or leave and have little or no apparent land use. In many cases mined landscapes around the world have resulted in a less functional and degraded environment, with deleterious impacts on surrounding ecosystems.This situation is now slowly being addressed, as global companies, academics and practitioners and their organisations have started to exploit the ideas from an integration of earth sciences and mining through the application of planning software dedicated to the design of landforms.This development has had its genesis primarily in the United States. We suggest that process has been driven, in recent decades, by the application of resources in response to the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), (USA Congress 11 December 1980) and other mine reclamation legislation enacted by federal and states regulators in the USA. The combining impact has seen a huge transfer of capital back from the public purse and ‘potentially responsible parties’, into abandoned mines to affect control, remediation, and reclamation/rehabilitation of those mines.Given this investment in rehabilitation and reclamation, people engaging in the business of landform planning have had the opportunity to address landform reclamation of historic and active sites. The skills of engineers and scientists with improved technology, waste rock characterisation and modelling tools have been combined resulting in the evolution of landform design and in mine planning of active mines. This has delivered cost-effective, sustainable mine closure designs for over 30 years. Integration of mine design with an understanding of geomorphic principals and the natural landscape, coupled with waste and soil characterisation, yield a positive result. Recently work has been applied across large and small-scale projects by companies. As these processes develop, ideas and concepts are evolving that active mines, or mines in the early planning stages, could use to help reduce double handling, and in the long run reduce overall project and closure costs, more effectively attain the desired final land use, and enhance the industry’s reputation and licence to operate.CITATION:Leidich, T,?Lacy, H?and Van?Zyl,?M,?2014. Application of design concepts and engineering controls necessary to deliver well-designed and rehabilitated landforms, in Proceedings Life-of-Mine 2014 , pp 55–66 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

The revival of the mining industry at Captain's Flat after a long period of years of inactivity has attracted attention to the importance of the ore-deposits of that field as potential sources of supply of lead and zinc. Mindful of the necessity for taking stock of the State's mineral resources, the Department of Mines of New South Wales as part of its programme of geological investigation, carried out a survey of the oredeposits and associated country rocks during 1938 and 1940.Surface geology was mapped in detail and all available exposures were examined and logged. Unfortunately, and this condition militates against the formulation of conclusions because of insufficiem.t data, some of the older workings, notably in Keating's Section, were inaccessible and the logging of levels and stopes is by no means as complete as could be desired. However, with the progress of development and exploration, further information of geological value will come to hand for incorporation in supplementary reports. It may be expected that, under such circumstances, modification of certain statements herein expressed may be necessary but it is not anticipated that any vital alteration will be occasioned.Within the State of, New South Wales, Captain's Flat ranks second to Broken Hill as a pqtem.tial producer of lead and zinc. In addition, large quantities of iron pyrites are available for the manufacture of sulphuric acid which finds application in the superphosphate industry.The mines are now controlled by an operating company known as Lake George Mines, Ltd., incorporated in New South Wales, the parent organisation being the Lake George Mining Gorporation Ltd., registered in London.Over £600,000 has been spent by the Company in exploration, mine development, surface plant, housing and water 'conservation, while the State' Government constructed a branch railway from Bungendore at a cost of £200,000. The various activities consequent upon these development and construction programmes and the prospect of employment in the industry has led to a rapid increase in the population of the township.The State, generally, has benefited to the extent of a substantial contribution to the relief of the unemployment problem, and it is hoped that reasonable permanency will be assured to some hundreds of workers for many years.

Jan 1, 1941

By I R. F MacCulloch, K Jones

Pintail Systems, Inc, a Colorado USA based company has developed and commercially applied bioremediation processes for biological detoxification of cyanide compounds in mine waste. Site-specific microorganisms are isolated from spent ore, tailings or process solutions and augmented in the laboratory for cyanide oxidation, denitrification and metal biomineralisation. Biological processes typically treat complex contaminants (cyanide compounds, soluble metals and nitrates) in a fraction of the time of conventional remediation processes. Cyanide is used in microbial metabolic processes as a carbon or a nitrogen source. Biological detoxification processes applied at the end of mine life can end long-term liability and perpetual monitoring and containment. Case studies from commercial application and demonstration programs for the US Environmental Protection Agency will be presented in this paper.

Jan 1, 2004

By J P. van Dijk, M Munro

Discrete vein modelling presents an innovative geology driven 3D modelling method for quantification of vein hosted mineral deposits, with far reaching potential for critical mineral supply and low impact resource extraction. By integrating key geological drivers with advanced discrete fracture network modelling, the DMX protocol (launched in 2019) converges to a more realistic representation of complex vein systems in three-dimensional space. The approach insights greater geologic reasoning in distributing mineral grades where vein boundaries are already defined. This presents a viable alternative to existing modelling and estimation methods and has important implications for mineral resource estimation and reporting. Further implications are discussed, where the enhanced understanding of complex orebody characteristics can potentially be used in optimising mining and mineral processing, supporting more sustainable and efficient mining practices.

Sep 1, 2024

By G Booth

Whilst communications systems in the mining industry have evolved over the years, the premise remains consistent that reliable communication is vital for safety and operational efficiency. TodayÆs open pit mines are benefiting from advanced developmental efforts based on mesh networking hardware and software technology. This paper highlights Rajant CorporationÆs adaptation of technology, originally developed for the defence and first responder industries, to provide wireless network connectivity in open pit mining applications. Featured is the large-scale deployment of over 300 mobile, meshing access points in the Bingham Canyon Copper mine near Salt Lake City, Utah, the worldÆs largest open pit copper mine. Many companies have positioned themselves, their technology and their product line in the arena of rugged outdoor wireless broadband mesh networking infrastructure. However, Rajant Corporation has combined specialised command and control software and portable networks which offer network extensibility and redundancy that are not available in any other networking solution. Rajant CorporationÆs BreadCrumb« offers unique traits in portability and non-line-of-site networking nodes which intelligently route and broadcast in standard 802.11 protocol. The advantage of RajantÆs solution is especially valuable for users needing equipment moved easily and rapidly into and out of the theatre of operations with uninterrupted network availability. The main differentiators that set the BreadCrumb« network apart from the competitors are mobility (continuous availability), simplicity, ability to properly load balance and power options. In 2007, RajantÆs BreadCrumb« wireless mesh system was selected by the Kennecott Utah Copper Corporation (KUCC), a wholly owned subsidiary of Rio Tinto, as its primary communications platform for operations within the Bingham Canyon Copper mine, the worldÆs largest open pit copper mine. The Rajant BreadCrumb« technology enables KUCC to gain additional operational efficiencies by tracking, monitoring and managing its copper mining operations. The primary goal of using the BreadCrumb« wireless mesh system Kennecott was to streamline its complex mining operations. KUCC required a high number of moving wireless nodes for improving mine monitoring and control. The Rajant InstaMesh« software running on the wireless BreadCrumb« units connects hundreds of devices to each other while rapidly transporting critical operational data. Kennecott has successfully implemented a large number of BreadCrumb« radios in an interconnected network that allows loader trucks, shovels, pumps, laptops and other production equipment to communicate with each other in real-time. These systems are a mix of secure access nodes that enable data and voice communications across a meshed, self-healing network for fleet dispatch, health monitoring and other critical mining applications. Many of the devices that require wireless communications are moving at all times throughout the wireless mining infrastructure. The BreadCrumb« nodes rapidly adapt to any changes in the network topology, assuring that IP traffic uptime and bandwidth are maximised. The installation layout and data network specifics, as well as maps and data network efficiencies will be detailed in the paper.

Jan 1, 2008

By A Murphy

Mining plants and infrastructure, and the decisions made by their designers, can have large impacts on their environmental and social context, commonly referred to as the site or plant footprint. They can also be the source of constructive contributions to sustainable development when designers are enabled via the information, systems and tools to incorporate sustainability in engineering processes. A facility’s footprint and the project’s contribution to sustainability – economic, environmental and social aspects – are now key considerations in regulatory approval processes and are the fundamental drivers of support, or opposition, from the project’s stakeholders.Historically, plant and infrastructure designers have not been well integrated with the environmental and social professionals who are engaged to pursue regulatory approvals. Despite this, many objectives central to technical and process engineering have in fact contributed positively to a facility’s footprint and indeed its contribution to sustainable development. Examples of these objectives include increasing process and energy efficiency, and minimising the quantities of waste requiring disposal. With the framework of sustainability, mining plant and infrastructure designers are indeed at the forefront of incorporating sustainability into resource industry projects and are central to the process of obtaining regulatory approvals and ongoing stakeholder support. The process of incorporation starts with a shared understanding of sustainability and sustainable development, and continues with project processes that facilitate information and knowledge exchange throughout the project life cycle.CITATION:Murphy, A, 2014. Incorporating sustainability into mining plant and infrastructure design, in Proceedings Life-of-Mine 2014 , pp 637–646 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By N Guresin, M Rohde

A lead-zinc flotation tailings sample containing silver from BHP Billiton’s Cannington Mine has been characterised to understand occurrences of silver in the tailings by conventional elemental, X-ray diffraction (XRD) and size analyses followed by mineralogical analysis with a scanning electron microscope (SEM) equipped with mineral liberation analysis (MLA) software and the use of an adapted diagnostic leach process originally developed for gold containing materials.The tailings sample contained 67 g/t Ag, 1.8 per cent Pb and 0.52 per cent Zn. The XRD analysis showed that the sample consisted of 74 per cent silicates, nine per cent sulfides, 11 per cent magnetite and small amounts of other minerals such as fluorite, fluorapatite and rutile. The p80 and p50 of the sample were determined to be 106 µm and 38 µm, respectively. The silver distribution was high in the small size fraction with 52.1 per cent of the silver being in the -8 µm fraction. The silver minerals freibergite, acanthite, jamesonite, pyrargyrite and native silver were observed in the mineralogical analysis of the sample by SEM/MLA. The associations of the minerals were intricate and the occurrences of silver were complex. There were finely disseminated silver minerals and also coarser grains of silver minerals in composites with the host minerals. It was estimated that almost 50 per cent of the silver was contained in pyrargyrite, around 14 per cent as native silver and contained in acanthite, 12.5 per cent in galena and around ten per cent in freibergite and jamesonite.These composite particles and the type of the silver minerals present were expected to limit leaching efficiencies of the silver in hydrometallurgical processing. The diagnostic leach tests showed that around 50 per cent of the silver could be recovered by direct cyanidation and higher extractions could be achieved by more aggressive acidic systems.Cyanidation tests were conducted to confirm the findings of the diagnostic leach studies. The investigated cyanidation parameters were time (up to 48 hours), solid to liquid ratio (1:1 and 1:2), cyanide concentration (0.025 M, 0.5 M and 0.1 M) and particle size (p80 of 106 µm, 63 µm and 7.5 µm). The effects of oxygen and lead nitrate were also studied. The tests were conducted at atmospheric temperatures. The maximum silver recovery obtained was about 50 per cent for all the parameter ranges trialled except particle size. The decrease in particle size from 106 µm to 7.5 µm by fine grinding resulted in an increase in silver recoveries from 50 per cent up to approximately 82 per cent indicating that the liberation of the silver grains/minerals is one of the factors affecting the cyanidation recovery of silver in addition to the presence of refractory silver minerals not amenable to cyanidation.Low head grades of silver in the tailings and relatively low cyanidation recoveries of silver (without fine grinding) necessitate a thorough cost analysis for the cyanidation of the Cannington lead and zinc tailings to assess if cyanidation would be a suitable process option for the extraction of silver. It is clear that one of the most important factors in determining the cost feasibility will be the price of silver in the world metal market.CITATION:Rohde, M, Guresin, N and Johnson, N W, 2014. Characterisation of silver minerals in lead-zinc flotation tailings and their response to cyanidation, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 163–172 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

By S A. McManus

With the advances in software speed and capability, many of us now are running multiple scenarios on entire models rather than just testing small areas or a few blocks. In the authors experience both the geological and geostatistical academic theory and our rules of thumb, often prove un-useable or incorrect in the real world we work in. The only way to truly validate and tune our models is to complete the entire model and ‘see if it works’. If it lacks some property we were expecting, then we need to find out why and/or run different scenarios to see what changes. This is not always possible with tight project timelines but we find ourselves doing more and more of this sort of thing, and in so doing, understand that every deposit is different and requires its own ‘rules’ to get valid and useful results. For the purposes of this paper, this process is termed Empirical Geostatistics. Take Clayton Deutsch’s ‘all realisations all of the time’ concept a step back. Before you even think of simulating, test the alternate realisations generated by alternate parameters such as different domaining, varying search neighbourhood parameters etc.

Mar 22, 2022

By S D. Fox, P B. Swart

Statistics showing that mine rehabilitation is falling behind rates of disturbance continue to be reported in the media. Unfortunately, most reported statistics do not account for the large growth-cycle that mining in Australia experiences, where there are typically significant new disturbances with large portions of these areas not being available for rehabilitation for a number of years. Many commentators assert that better planning is required to ensure that rehabilitation will be able to achieve a safe, stable, non-polluting landform that meets the agreed post-mining landuse.This paper focusses on the revegetation aspects of mine rehabilitation and in particular the matters that need to be addressed in the planning stage so that revegetation success is ultimately able to be demonstrated to regulators and other stakeholders.CITATION:Fox, S D and Swart, P B, 2018. Planning revegetation for relinquishment, in Proceedings Life-of-Mine 2018, pp 113–115 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By M Fritz, B Ziegelaar

"For moisture samples, the International Standard for iron ore sampling states the following: Moisture samples shall be processed as soon as possible and test portions weighed immediately. If this is not possible, samples shall be stored in non-absorbent airtight containers with a minimum of free air space to minimise any change in moisture content, but should be prepared without delay. ISO 3082 (2009)Prescribing what to do is of course easy. Putting it in practice is, however, a little more problematic.The iron ore industry has seen quite some changes in the last ten to 15 years, such as: a large increase in the volume of seaborne trade new ore types and blends coming onto the market new mines, processing plants and port facilities producing more and loading faster an increase in wet processed ore products a dramatic rise and then equally dramatic fall in the iron ore price followed by a recent recovery.All of the above have had an effect on sampling facilities. The large increase in volume coupled with ambitions such as labour efficiency, safer operations and higher precision has driven the installation and retrofitting of automated sampling and robotic sampling preparation plants in order to keep up with increased quality control.Designers of sampling facilities are invariably instructed to build plants that comply with ISO 3082. In general this means that the plants are compliant in respect of the number of primary increments, gross sample masses and sample division rules. The clause at the beginning of this abstract is mostly overlooked as it only appears in a section (4.1) describing the basic requirements of a sampling system.An error of 0.1 per cent in moisture changes the value of 1 Mt of iron ore at US$50/t by US$50 000. At 700 Mt/a of Australian iron ore exports, this is US$35 M. Frequently, errors from 0.5 to 1 per cent in moisture measurements are encountered.In comparison an error of 0.1 per cent Fe is US$0.081 (US$50/t and 62 per cent Fe base) per tonne, that is US$81 000 per Mt or about US$51 M for the same Australian annual iron ore exports.It is somewhat mystifying that we in the ISO Technical committees spend extraordinary energy (= money and time) on improving measurement techniques, whilst the big costs are in sampling errors. This is particularly true for moisture measurement. Our paper quantifies some of the sources of moisture measurements errors and suggests mitigating actions.CITATION:Ziegelaar, B and Fritz, M, 2017. Sampling for the percentage moisture in the iron ore industry, in Proceedings Eighth World Conference on Sampling and Blending, pp 271–274 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

May 9, 2017

By S J. Clarke, G Sieders

Double corrosion protection (DCP) rock bolts have evolved to become complicated assemblies comprising numerous components. This complexity is mainly associated with durability considerations including potential exposure to adverse groundwater conditions and ensuring separation of dissimilar metals within the bolt assembly itself.Recent progress in the construction of glass-fibre reinforced polymer (GRP) rock bolts have the potential to provide a viable alternative to conventional steel rock bolts in civil tunnelling applications. The durability of the material results in a much simpler bolt detail and permits the use of resin rather than solely cement based grouts.This paper presents the findings of the comparative structural testing of GRP bolts with conventional DCP steel bolts. The axial load performance, including stiffness, ultimate capacity and ductility of bolts are compared. Shear behaviour of bolts is considered, including durability issues associated with damage to the plastic sleeve used in DCP bolts.The paper also considers other issues which are relevant to the design of temporary and permanent rock bolts used in tunnel support, such as initial tensioning and grouting. Long-term performance, including durability and creep are also reviewed.CITATION:Clarke, S J and Sieders, G, 2014. Comparison of glass-fibre reinforced polymer rock bolts with double corrosion protection steel rock bolts for use in tunnel applications, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 237–246 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By S Mitra, D O’Dea, N Barrett, T Honeyands, P Zulli

The steel industry continues to explore and demonstrate technologies that decrease its greenhouse gas emissions, especially in blast furnace ironmaking where alternate operating conditions will be required. As the furnace has been optimised over many years, it is approaching the minimum fuel rate possible with coke and Pulverised Coal Injection (PCI). Alternative operating conditions are therefore required to further decrease greenhouse gas emissions. Because of this, hydrogen has been proposed as a reducing agent in the blast furnace. Injection of hydrogen through the tuyeres was assessed using a comprehensive 2D blast furnace global model. The model was calibrated to a blast furnace operating with PCI as a base case and various approaches to hydrogen injection assessed, with a particular focus on displacing PCI. The maximum hydrogen injection rate of 19.5 kg H2 per tonne of hot metal was predicted, limited by decreases in the raceway adiabatic flame temperature and top gas temperature. Internal blast furnace conditions, such as gas composition and reduction degree were also predicted. Holistic analysis was performed to estimate the effectiveness of hydrogen injection on reduction of greenhouse gas emissions. Based on these results, the changes in blast furnace operation and emissions under hydrogen injection are discussed.

Nov 8, 2021