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By J Palise

As cities become more populated and the need for tunnelling increases, we continue to dig deeper urban tunnels in more challenging ground conditions. At the same time our expectations for durability and long-term performance are increasing.It has become increasingly apparent in recent years that repairing water leaks in tunnels can be very costly and unplanned infiltration can cause undesirable outcomes for long-term maintenance costs, structural durability and environmental impacts. For this reason, tunnel constructors are investing more time and effort upfront into drainage and waterproofing systems.Tunnel membrane systems are becoming accepted as a necessary part of tunnel construction, however the knowledge surrounding selection of appropriate systems, design detailing and installation methods has not increased at the same rate. Currently Australia relies heavily on International Standards from Europe and the United States with no immediate program in place to establish our own locally relevant industry standards.This paper gives an overview of where the industry in Australasia is heading in terms of adopting relevant standards. Current basic waterproof detailing options for drained and undrained tunnels with success and failure of various methods are also addressed. Finally we look at the Brisbane Airport Link as a case study for how tunnel waterproofing contract methods, design and installation issues are being addressed in context with recent projects including the Epping to Chatswood Rail Link in Sydney, Auckland Northern Gateway Tunnel, Eastlink Tunnel in Melbourne and Sydney City West Cable Tunnel.This paper’s primary objective is to propose guidelines for how tunnel waterproofing could be implemented on large infrastructure projects in the future and to map a path for preparing and introducing a ready to use document for selecting appropriate tunnel membrane and drainage systems whilst implementing detailing methods which are appropriate for local conditions.

Mar 8, 2011

By W Kendall

Ore sorting has the potential to reduce the feed to wet plants and in the case of complex orebodies that can significantly reduce the water, energy and reagent consumptions and resulting operating costs for the project. The application of ore sorters has sparked renewed interest and application in the precious and base metals mining industry in recent years as a result of the continuing development of new sensing technology and very fast information processing that is making ore sorters applicable to a much wider range of ores and larger scale operations. The application of ore sorters involves a range of trade-off decisions that have economic impact upon the benefits of ores sorting to the project under consideration. This paper will present some typical trade offs to be considered and their impact in a particular project setting. CITATION: Kendall, W, 2018. How economics drive the application of ore sorting, in Proceedings Complex Orebodies Conference 2018, pp 24–27 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

By E Nunes, R Mendes, D Jacobson, G Cota, T Machado, E Santos, J Almeida, E Pereira9, B Raso

Grinding circuits are known to be the highest consumer of energy used in the ore comminution process, with high operational costs and sensitivity to ore conditions. The mining industry is being encouraged to look for more energy efficient processes while increasing the mass and metallurgical recovery; a specific example is projects with lower iron ore grades, which demands a higher level of liberation and resulting higher energy consumption. This has led to increased usage of high-pressure grinding roll (HPGR) technology as an alternative design within the comminution circuit. A growing use of the HRC™ HPGR technology has been used to generate concentrate through a more sustainable process. In the Brazilian state of Minas Gerais, the readaptation of iron ore beneficiation circuits has been initiated, replacing the traditional crushing-to-grinding flow sheet with circuits using crushing-to-HPGR flow sheets, with the main driver being reduced energy consumption. Utilising results from sampling campaigns and analysis of experimental data collected in an industrial plant, the work herein presents a case study from the JMN Mineração operating plant, where the HRC™ HPGR was used as an alternative to traditional grinding using horizontal mills. The results show that the HRC™ HPGR performance in this iron ore processing plant showed benefits in terms of reduced energy consumption as compared to the projected performance with a traditional grinding circuit.

Sep 18, 2023

By E Mielczarski

Determination of the adsorbed layer composition and structure at molecular and atomic levels and understanding adsorption mechanisms and dynamics are vitally important for the preparation of surface layers with specific functions. Direct information, at a molecular level, about mineral surface composition, its structure and surface distribution is crucial to perform an efficient separation process for mineral beneficiation. This information is equally important for modifying surface properties of industrial minerals for specific applications such as: fillers, composites, weathering resistance, etc. An understanding of the mechanisms and kinetics of the interaction of first adsorbed organic molecules with mineral surfaces is a fundamental requirement for the prediction and control of the macroscopic surface properties governing the efficiency of separation technologies or new material formulations. The developed infrared external reflection technique has a unique ability to study interface phenomena, at a molecular level, on heterogeneous substrates. The variety, precision and reliability of information about the interface phenomena delivered by this technique is superior to any other single technique. The experiments are fast and non-destructive. High sensitivity (starting from 20 per cent of the monolayer) in situ collected information in a multiphase system, even in the region of strong absorption of the substrate, makes this technique a very valuable experimental tool. The complexity of the recorded reflection spectra, their sensitivity to variations of the optical properties of all bulk and surface components and their spatial distribution in the system under investigation, are in fact the major strengths of this technique. A few examples of the application of this multi-diagnostic technique, for monitoring surface modifications of semi-soluble minerals for selective flotation, will be discussed in detail in this paper.

Jan 1, 2005

By G Davison, C Rossimel, M Bouazza

Expanding rock bolts anchor within a rock mass more efficiently than non-expanding varieties. This is of great importance in weak ground conditions, where grouted friction bolts perform less efficiently than in good ground conditions. Filling a Split Set with demolition concrete has been shown to double the load-carrying capacity when compared to conventional use of Split Sets. This report details verification of these results by installing and pull-testing 14 Split Sets of varying grout conditions within in a fault zone. These Expanding Split Sets achieved loads double and triple that of ungrouted and normally grouted conventional Split Sets. A literature review and chemical analysis were conducted to understand the expansion process better. It was found that 20 per cent more calcium is included in expanding cement, which is responsible for its growth. Factors most affecting the expansion process were identified. Furthermore, the expansion rate of a bolt outside a borehole was measured and 6 mm of expansion across its diameter was found. The compressive properties of the cement were compared with other types, due to expanding cement becoming uncohesive after the expansion process is complete. When confined within a Split Set, compression testing demonstrated that this grout is just as strong and rigid as normal grout. Finally, the bolts were tested by shear and it was found that the Expanding Split Set (ESS) has a similar shear capacity to grouted Split Sets, which is 70 per cent higher than that of ungrouted Split Sets. These results enabled the mechanism for improved performance in weak ground conditions to be verified. Expanding grout will expand the Split Set into its borehole of varying diameter and lock it into place, creating increased friction and resistance to pull-out. This paper shows that ESSs can be a useful reinforcement technique in weak ground conditions.CITATION:Rossimel, C, Davison, G and Bouazza, M, 2014. An investigation of expanding split sets in weak ground, in Proceedings 12th AusIMM Underground Operators’ Conference 2014 , pp 159–170 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 24, 2014

By J Vann

The philosophical context of many activities in mine geology can be an important lever in adding value to operations. For mine geologists (including resource and grade control geologists) we argue that the tasks of problem formulation, observation and data collection, interpretation and modelling invoke various philosophical considerations whether the practitioner is aware of them or not.Constructing testable models to explain reality is the definitive aspect of any activity claiming to be ‘scientific’. A primary goal of mining geology is to build models that accurately predict reality to an acceptable degree and these include litho-structural, stratigraphic, grade control, resource or reconciliation models. What’s more, in mine geology we are often able collect additional drill samples or access new underground openings, for example, that can provide relatively rapid feedback on how predictive, and therefore useful, our models are. In this paper, we describe the key philosophical frameworks proposed for conducting scientific investigations, including falsification, the method of multiple working hypotheses and structural concepts of scientific theory. The strengths and weaknesses of these approaches are discussed and an attempt is made to relate them to activities undertaken by mine geologists. Common perceptions of what constitutes the scientific method have been dominated by how scientists do experimental physics and chemistry in particular. There are very important differences in the types of problem confronted in these experimental sciences compared to the ‘historical sciences’, such as geology, where the processes studied are unique and only evidential traces of past events are available. The philosophical implications of attempting to validate numerical geological models, such as resource estimates are also briefly considered.Some practical conclusions are drawn about how mine geology activities can be better implemented if practitioners are cognisant of the importance of philosophical considerations when attempting to gain new knowledge through a scientific investigation. We believe that the implications for creating additional value to a project or operation can be very significant when geology is applied by a practitioner with an understanding of the philosophical basis of the activities we think of as constituting a scientific investigation.Remember that all models are wrong; the practical question is how wrong do they have to be to not be useful? (Box and Draper, 1987, 74 p).The demand that theories be highly falsifiable has the attractive consequence that theories should be clearly stated and precise. If a theory is so vaguely stated that it is not exactly clear what it is claiming, then when tested by observation or experiment it can always be interpreted so as to be consistent with the results of the test. (Chalmers, 1999, 67 p).

Aug 22, 2011

The basic make-up of the majority of currently produced bulk explosives has changed little in the last 20 years. These explosives would be described as mature in a life cycle analysis. Therefore these explosive products and the practical rules for their use are well understood and well established. In recent years there has been interest in low density explosives, predominantly due to ammonium nitrate shortages and the associated increase in the cost of explosives. In the use of low density explosives some of the practical rules for the more commonly used bulk explosives do not apply. Therefore a shift in the thinking among users is required. At a number of mines low density explosives have been trialled or are being used, utilising the practical rules that apply to bulk explosive products. This has led to poor blast results in many situations. These poor blast results have often then led to a reduction in the use of low density explosives at the mine. This reduction does not acknowledge the advantages that can be gained from this product in the area of reduced cost of mining. This paper looks at low density explosives and discusses how and why these products work. Included in the paper are some practical ideas and examples of how low density explosives can be effectively used at the mine site.

Jan 1, 2007

By L Boczek

The term Engineer of Record (EoR) is commonly used in North America and South Africa to define the responsible person for the design, construction and operational phases of a tailings storage facility (TSF). Recently, this role has been elevated in prominence within Australia, but what does it really mean? Recent updates to international TSF guidelines suggests appointing an EoR is good practice, but where does the responsibilities of the EoR start and finish. Interestingly, both Samarco and Mount Polley failures had active EoR’s in place. This suggests that nominating an EoR alone, is not the full answer to mitigating the potential for a TSF failure. Appropriate construction and operational practices are key to the success of the design of TSFs, where all too often, operators ignore the operating plans developed by the designer. To be successful, a key consideration of the EoR role, is involvement in the operational phase of the TSF. This requires ‘buy-in’ from the mine managers and a change in the way TSFs are perceived by site. This paper explores how the roles and responsibilities of the EoR can assist in improving governance of TSFs if implemented effectively and what role the client has to ensure the success of the EoR.

Jul 1, 2021

It is very rare in the underground hard rock environment to find a deposit that is ideally suited to a specific mining method. Usually the irregular shape of the orebody will allow the deposit to be extracted by more than one mining method. During the prefeasibility stage, a number of conceptual mine designs are generally evaluated to see which offers the best method of extraction for the deposit. The selected method is usually based on key decision criteria such as the overall extraction of the orebody, the amount of metal produced annually and the unit cost of production. Often the prefeasibility study document will state that the project has an NPV of æxÆ million dollars. This statement can be made without any quantitative consideration of the likely risks of the mining methods reviewed or the level of confidence in the estimation of the NPV. By assigning a probability of failure to each component of the mining cycle a measure of the risk for each method can be determined. One mining method may provide the highest NPV when it is performing well, however, there may be a higher risk of a major failure impacting on the performance of that method, eg the failure of a mass blast of a crown or rib pillar. This paper will present a flowsheet approach to the use of risk analysis for determining the likely production rates of different mining methods. This framework allows the annual metal output to be estimated and from this the NPV for each method. A level of confidence can be applied to the estimated NPV for each option. An example will be presented on how this technique has been used within the Normandy Group.

Jan 1, 1998

By M Haest, O Dominguez, D Mittrup

With the current focus in the mining industry on reducing costs, while simultaneously improving ore quality, infrared spectroscopy is a tool that can potentially assist companies to meet both challenges. Changes in the nature of infrared spectra are strongly influenced by changes in mineralogy, which is a key input variable for exploration (geology and orebody modelling and ore characterisation) and mining (pit design, mine scheduling and processing plant design/management).Infrared spectroscopic logging of drill holes has been embedded as a standard tool in BHP Billiton Iron Ore exploration, with a process set up to automatically deliver mineralogy and associated imagery to the end users (typically exploration geologists). The availability of consistent and automated mineralogy drill hole logs across a project is improving the output quality and reducing re-work.BHP Billiton Iron Ore is now looking into using the same infrared spectroscopic data for other applications, including improving predictions of geometallurgical and geotechnical parameters. Trials show that addition of infrared spectroscopic data to conventional data sets (element analysis and depth information) is significantly improving the accuracy of regression models to predict the lump-fine ratio.Further initiatives around infrared spectroscopic data in BHP Billiton Iron Ore include the installation of infrared spectroscopic sensors over conveyor belts, infrared spectroscopic mine face scanning and infrared spectroscopic blasthole logging. The ultimate vision is to have consistent, seamless mineralogical data from infrared spectroscopic sensing available throughout the mineral value chain (exploration/mining/processing). This seamless infrared spectroscopic data ‘bridge’ will allow the transfer of knowledge between the different sections of the value chain (exploration, mining and processing). For example, ore handle-ability could be predicted on exploration samples using regression models built from processing plant observations. In the opposite direction, information gathered about the buried stratigraphy by infrared spectroscopy utilised during exploration, could be used to predict the stratigraphy encountered during mining. This collaboration across BHP Billiton Iron Ore is expected to deliver significant savings, while improving the quality of the final product, thus helping to drive efficiency over the next decade.CITATION:Haest, M, Mittrup, D and Dominguez, O, 2015. Reaping the first fruits – infrared spectroscopy: the new standard tool in BHP Billiton Iron Ore Exploration, in Proceedings Iron Ore 2015, pp 277–284 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

In todayÆs evolving and globalised world, mining companies are being pressured to move beyond compliance towards long-term sustainability and sustainable development. Companies are expected to æengageÆ communities and measure the success of these engagements without a clear understanding of æhowÆ to do this. This move, away from compliance, develops more of a focus on sustainability and æcommunityÆ social responsibility rather than corporate social responsibility. This shift leads to the development of world-class projects that provide sustainable development for people, reduce the incidence of costly delays, and promote good global citizenship for companies. The process of æengagingÆ communities in mining project design and development leads to sustainable development, a stronger license to operate, and a reduction in social and political risk. To create this mutually beneficial relationship between communities and companies, communities must be æengagedÆ in the project development and risk assessment processes as early as possible, preferably during the exploration or the concept phases. How to create this æengagementÆ and manage this risk will be discussed.

Jan 1, 2007

New Celebration Gold Mine is located 35 km SE of Kalgoorlie, Western Australia, in the Archaean Kalgoorlie-St Ives Greenstone belt. The leases total 119 sq kms and arepart of a joint venture between Newmont Australia Ltd (as manager) and Mt Martin Gold Mines N.L. Mining commenced in August, 1986 and is now producing over 115,000 ounces of gold per annum. A variety of gold mineralisation styles with a total resource of 23.5 million tonnes at 2.19g/t are associated with shear zones at New Celebration. Gold production is co-ordinated from 7 open pits with others planned to com- mence soon. A large scale underground trial mining operation has com- menced with a decline on the hanging wall of the main producing orebody, Hampton Boulder. Millfeed produced is classified on the stockpile according to grade and metallurgical performance and blended tomaximise throughput while main- taining grade through a CIL treatment plant currently operating at 1.7 million tonnes per year.

Jan 1, 1991

By D Cooke

In 2010, Kalgoorlie Consolidated Gold Mines (KCGM) was Australia’s largest gold producer, with total annual production of 788 000 ounces. Of the gold produced by KCGM in 2010, 95 per cent was extracted from the Fimiston open pit, also known as the Superpit. The Fimiston operation encompasses the historic Golden Mile, from which more than 55 million ounces of gold have been extracted from the world-class Fimiston lode style mineralisation.The operational performance of the KCGM Fimiston open pit was reviewed for the period between 2005 and 2010. Key performance metrics reviewed included mined tonnes and grade, cost per ounce of gold produced and the mine to mill reconciliation trends. The years 2007 and 2008 were characterised by a decline in performance against key performance metrics. The ore zones were diluted, with the excess tonnes mined resulting in lower grade and an increase in the cost per ounce. Poor reconciliation between ore mined, the ore reserve model and the grade control polygons was also observed.A series of improvement initiatives were implemented in late 2008. As a result of changes made to the grade control and mining practices, the site performance recovered. Unplanned dilution was reduced, which had a positive impact on mined grade. The lower tonnes combined with higher grade reduced the cost per ounce to below budgeted levels in 2009 and 2010, enhancing the profitability of the operation. The operational performance between 2005 and 2010 was compared to the turnover statistics for the KCGM geology department over the same period. Turnover accelerated between 2005 and 2007, peaking at an annualised rate of 43 per cent. With the onset of the Global Financial Crisis and the implementation of retention initiatives, turnover reduced significantly between 2008 and 2010. A strong consistent correlation was observed between the turnover trends in geology and the performance of the grade control function and resultant site metrics.The cost of turnover is known intuitively, however, rarely quantified. To evaluate the benefit of the improved performance, a detailed financial model was used to quantify the impact of the grade control function. In 2010, the headgrade exceeding budget by just four per cent contributed an additional A$24 M of value to KCGM. In contrast, if the 2008 performance had been replicated in 2010 (-9 per cent on headgrade), the result would have removed A$61 M in value from the business. The KCGM experience between 2005 and 2010 demonstrates the value of human capital in a mining operation and the importance of a high performing geology grade control team to the profitability of a mining operation.

Aug 22, 2011

By G R. Hancock, S Grant, T Whiteside, J B. C Lowry, J Boyden, T J. Coulthard

Physically-based landform evolution models (LEM) provide a spatial framework to forecast the long-term geomorphic stability of post-mining landscapes. When used to test the relative stability of different landform designs, LEMs may assist with the development of optimal closure designs for rehabilitated mines. However, in order to reduce prediction error, factors controlling landscape evolution must also be accurately represented by models. This requires that the correct sets of processes are represented and that driving parameters used in LEMs are, if necessary, calibrated to the landscape of interest.Vegetation exerts strong controls on the hydrologic and geomorphic processes that drive landscape evolution. Hence, the spatial and temporal scales over which typical patterns in vegetation are represented in different landscapes are important considerations in LEM calibration. However, vegetation is rarely accounted for in LEMs and even when integrated is often represented simply, without representing spatial dynamics of vegetation cover that may impact landform development.This study focuses on characterising vegetation patterns to calibrate a new vegetation module of the The Cellular Automaton Evolutionary Slope and River (CAESAR)-Lisflood LEM to be applied to a conceptual rehabilitated landform of the Ranger uranium mine located in the Alligator Rivers Region (ARR) of northern Australia. In the ARR the spatial dynamics of vegetation over time are largely driven by monsoonal rains and topography. Extensive dry season fires are also common in the region, temporarily reducing vegetation cover where they occur. Hence, hydrology, topography and fire disturbance interact to shape a distinct, yet dynamic, mosaic of different vegetation types of varying cover density. As a basis for calibrating the new vegetation function, the distribution and dynamics of vegetation are characterised for this savannah landscape by remote sensing, in conjunction with ground data.CITATION:Boyden, J, Lowry, J, Coulthard, T, Whiteside, T, Hancock, G and Grant, S, 2016. Accounting for vegetation dynamics in landform evolution modelling, in Proceedings Life-of-Mine 2016 Conference , pp 63–66 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By W D. Erskine, M J. Saynor

Ranger Uranium Mine, surrounded by Kakadu National Park is located in the Alligator Rivers Region (ARR) in the wet-dry monsoonal tropics, 250 km east of Darwin, Northern Territory. A trial landform (TLF), measuring approximately 200 m by 400 m (8 ha) was constructed during late 2008 and early 2009 by Energy Resources of Australia (ERA), adjacent to the northwestern wall of the tailings storage facility at the Ranger Mine. A collaborative research program involving the Environmental Research Institute of the Supervising Scientist (eriss) and ERA, has been underway to measure long-term (five to ten year) rainfall, run-off, sediment and solute losses, seepage and vegetation establishment on the TLF (Saynor et al, 2012; Lowry et al, 2014). This paper reports on bed load losses from four erosion plots built on the TLF. These were achieved by physically isolating approximately 30 × 30 m areas from the surrounding landform on three sides with sidewalls along with an open polyvinyl chloride (PVC) pipe on the downslope side. Each plot was instrumented with a range of sensors. Two plots, 1 and 2 were constructed on waste rock material, while plots 3 and 4 were constructed on waste rock mixed with approximately 30 per cent lateritic material. Plots 1 and 4 had tube stock planted in early 2009, and plots 2 and 3 were initially planted by direct seeding in July 2009 and were infill planted with tube stock in January 2011.CITATION:Saynor, M J and Erskine, W D, 2016. Bed load losses from experimental plots on a rehabilitated uranium mine in northern Australia, in Proceedings Life-of-Mine 2016 Conference , pp 168–171 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By S Graskoski

The allocation of boggers and trucks at Telfer’s sublevel cave mine is currently assigned by manual techniques, with decision-making primarily dependant on the judgement of the operators and mine control. Field observations indicate that allocation decisions could be improved by establishing a systematic approach to dispatch. An investigation into the current state of technology determined that no currently available solution would provide a tool to make optimal decisions for the Telfer dispatch challenge.In an underground sublevel cave (SLC) environment, the destination decision is fixed and the source is variable, so open pit and block cave solutions are not relevant. Newcrest underwent a development venture with an external vendor to develop a novel production dispatch algorithm and user-friendly software program to make allocation decisions in a systematic way with consideration given for the true complexity of the operation.This new production software, nicknamed Dingo (for Dispatch ‘n’ Go), is a smart way to assist forepersons and mine control operators in their day-to-day roles of planning shifts and allocating trucks and loaders to optimal locations during shifts.CITATION:S Graskoski, 2017. Dingo – an optimisation tool to solve complex short interval control at Telfer underground mine, in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 261–266 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 16, 2017

By F D Durao, Muge F. H, Rogado J. Q

In the scope of the project named CAPUME II (EEC BRITE/EURAM contract - project MA2M-CT90,-0042(SMA)) for the development of an integrated mine planning system for underground mines, two of the main tasks were the development of a short-term mining planning procedure (module) and a numerical simulator of the mineral processing plant of Pirites Alentejanas - PA. The short-term mining planning module defines the mining sequences by solving a constrained minimisation problem. The ore grade variability is the objective function subject to the geometrical constraints of the mining method and to the maximum of `internal blending'. The optimisation problem is solved by applying a dynamic programming algorithm. The plant simulator is an essential tool of the planning system allowing the preview of metal grades/recoveries of copper, lead and zinc of concentrates streams, given the corresponding metal assays of the run-of-mine ore, defined by the short-term mine planning module. This way, the management can plan the short-term mining operations (the weekly sequence of exploration blocks and the internal planning) in order to fulfill given required conditions, based on a shipment schedule and on a purchaser's formula. In this paper, after a short description of the short-term mining planning module and of the simulation package named SIMUL, a synthesis of the main model development steps and the results of some simulation runs are presented and discussed.

Jan 1, 1995

Minerals and Metals Group (MMG) Century mine (Century) is a large open-cut mine in northwest Queensland approximately 2.5 km long, 1.5 km wide and 240 m deep, with an ultimate pit depth of 320 m. In 2009, the mine experienced three failures which began as small failures, and progressively developed into significant multi-batter failures. The incidents were managed by a combination of analysis, redesign and practical management to achieve positive outcomes for the mine. On the south wall of the mine, a series of batter-scale wedge failures occurred in December 2007. Analysis of structure orientations and design changes aimed to minimise the risk of failure extending over multiple batters, while accepting a risk of further small-scale failures. Design changes were constrained by a culturally sensitive area (CSA) located south of the wall. As mining progressed, shallow wedge failures developed over multiple batters and cracks were observed 60m back from the pit crest, indicating that a large-scale wedge failure was developing. Movement increased in January 2009 as a result of significant rainfall. After considering several design options, the area was stabilised by a cut-back of the wall. Two multi-batter failures also occurred on the north wall as mining progressed through a structurally complex area. Both north wall failures began as small failures that progressively developed, and required a redesign of the wall below as well as practical management of safety aspects. The complex structural geology was difficult to predict ahead of mining, and required geotechnical input into design changes as mining progressed. All three failures potentially had significant impact for ore recovery, and were managed by a combination of analysis, redesign and operational management have resulted to achieve positive outcomes in a challenging mining environment.

May 1, 2010

By D Maldonado

BlueScope Steel’s Port Kembla sinter machine underwent a major upgrade during mid-2009. The mixing and rolling drum (MRD) was thoroughly cleaned during the upgrade. Space factor measurements taken in October 2009 showed that the drum was operating in the cataract regime in the dry mixing section and the cascading regime in the rolling section, which is optimal for granulation. Sampling carried out during an entry into the MRD showed that both the Sauter mean diameter and the predicted bed voidage increase rapidly during wetting, and then decrease in the wet mixing section. In the rolling section, the granule properties remained constant untilthe drum discharge. Frozen particle analysis, using liquid nitrogen as the quenching agent, were carried out on material collected from the MRD discharge. The results, expressed as a Granulation Index, showed there had been a significant improvement in the granulating performance of the MRD following the upgrade. The plant studies were also complemented with laboratory scale experiments which aimed to optimise the granulation process. The effect of burnt lime on green feed permeability was quantifi ed using the laboratory scale drum at different moisture contents. A significant increase in permeability was apparent once the burnt lime dosing rates doubled from 1.1 - 2.2 per cent w/w (feed basis). The capacity of the burnt lime system at the sinter machine will be increased in order to benefi t from the expected higher permeability, permeability, which will enable the machine to sinter at deeper bed heights.

Jul 11, 2011

By J Herrmann, J Richards, B Hutchison

An extensive trial of laser-based survey and monitoring systems at Hillgrove Resources Kanmantoo Copper Mine in the Adelaide Hills, South Australia, has proved the capabilities of the system in monitoring rock movements on open pit walls. Initially, the trial involved deploying a Maptek I-Site 8820 laser scanner and the proof-of-concept Maptek Sentry software in the Nugent Pit to monitor ductile rock movements located up to 260 m away. The system was proven to be capable of monitoring various rock movements from 1.5 tonne rockfalls up to a 40 m high toppling wall failure. Data collected from smaller rockfalls was used to help build a database for Hillgrove’s rockfall management program. As part of the trial, the laser scanner was deployed to monitor a ramp movement event, as well as the toppling failure, adjacent to an IBIS slope stability radar. Both devices monitored the slump and the slowly developing toppling movements, with similar results. Although the radar was used as the successful ‘critical alarm’ device for the toppling failure, post-failure analysis showed the laser-based system to be capable of performing a similar role in the ductile rock regime; albeit over much shorter distances than the radar capability. A second laser scanner was deployed to monitor Kanmantoo’s Emily Pit in early December 2014, where it successfully provided critical alarm warnings for a block topple event. Sentry software, which takes advantage of Maptek I-Site 3D spatial imaging technology, was first released in November 2014 to meet industry demand for a cost effective, flexible system to detect movement. Sentry has now been re-launched as a fully transportable monitoring system. Deployed in a custom trailer, the system offers a power and communications module, cellular and Wi-Fi networking and a stable bollard for the I-Site laser scanner and Sentry software. This paper will present rock wall movement data from the Sentry trial and a subsequent two years of monitoring of the open pit walls at the Kanmantoo Copper Mine, at distances out to 750m. In addition, examples of remote geological mapping and small rockfall detection, using the laser scans, will be described. The Sentry system has proven to be beneficial for the continual improvement of slope monitoring and risk management at hard rock mines. CITATION:Hutchison, B, Richards, J, Richards, J and Herrmann, J, 2018. Mine rockfall and rock wall failures – proven digital laser-based approach for monitoring slopes at the Kanmantoo Copper Mine, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 463–472 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018