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By T A. Helms, P Gottlieb, S E, R Bateman

In response to the ever-increasing challenges facing the modern gold mining industry and the need for improved gold recoveries within all processing streams, CSIRO has upgraded its latest automated mineralogical analysis system, QemSCAN (formerly QEM*SEM), with special purpose hardware that speeds up the location and measurement of precious metal-bearing phases. By rapidly scanning the surface of polished blocks, and accepting only fields that contain the minerals of interest, QemSCAN is able to find, map, and quantify target minerals in extreme detail. Phase identification and quantification is achieved by placing a grid of points over the target particle and collecting X-ray information at each analysis point. The resulting mineral maps provide the metallurgist with a complete textural description of all gold-bearing phases within the product measured, together with quantification of the gold phases in terms of their modal abundance, particle size, mineral associations, relative contributions to gold deportment and liberation characteristics. Examples are presented which illustrate how QemSCAN is able to find and quantify gold-bearing phases within low-grade ores from the Super Pit, Kalgoorlie. This work is the result of a collaborative project between Kalgoorlie Consolidated Gold Mines (KCGM), CSIRO Minerals, and the University of Queensland, and is on-going.

Jan 1, 2000

Folklore suggests that oxidation is detrimental to sulfide mineral flotation, and in many instances is the reason given for values reporting in the tailing. However, while a considerable body of work examining galena oxidation is available in the literature there are very few studies that investigate the consequences of galena oxidation on its subsequent flotation in base metal sulfide ores. This work clearly demonstrates that pyrite forms a galvanic couple with galena, due to the large difference in their rest potentials, and results in accelerated oxidation of galena, particularly as the pyrite content of the ore is increased. The most obvious effect of the galvanic oxidation of galena by pyrite is the release into the system of galena oxidation products, providing an ample supply of lead ions available to activate gangue minerals, most notably of which in lead/zinc ores is sphalerite. The inadvertent activation of sphalerite by lead ions inevitably leads to the recovery of liberated sphalerite into the lead concentrate, and as a consequence a reduction in the lead concentrate grade. That is, a loss of selectivity for galena against sphalerite. If galena oxidation is excessive not only is there a considerable loss in lead concentrate grade, but also a marked decreased in lead recovery as the flotation rates of the gangue minerals increase, until they rival that of galena.

Jan 1, 2005

By W Roy

When it comes to plan implementation and securing success in organisations in the 21st century, if there was such a thing as the secret to success it would be effective communication. Commoditisation brings financial, operational and cultural advantages to organisations that use effective communication. Effective communication tools turn æpeople problemsÆ into system control solutions, removing personality clashes that hide procedural malfunctions. By introducing communications frameworks available in the market place today, and case studies of their use, this paper provides insights into the successes available to organisations courageous enough to redefine their communications for the 21st century.

Jan 1, 2006

Excavator output rates given in Makers' catalogues are sometimes based on favourable operating conditions. Mine operators and planners are more interested in the Effective Hourly Output in normal operation (Qe) a plant system can give hour by hour and year after year in a particular application. The number of hours mining plant will be available for normal operation will be less than the annual total of 8760 h. The number of the available hours which can be utilised at Qe will depend largely on the number and types of units in the plant system, the manners in which they are applied and the nature of the deposit in which they work. The emphasis herein is on continuous systems for deep stripping with BWE's as the primary excavator. Examples and suggestions are given for the annual hours at Qe for some BWE systems.

Jan 1, 1981

By W Assibey-Bonsu

The paper provides a brief review of the multivariate uniform conditioning and the localised multivariate uniform conditioning techniques and presents a case study based on a porphyry copper gold deposit in Peru. Two other important scenarios have been investigated and will be particularly emphasised: The recovered selective mining unit (SMU)s depend on a combination of copper and gold content, which can be expressed by means of ænet smelter returnsÆ (NSR). Two approaches are compared. Firstly, the application of a composite cut-off on NSR on the joint distribution of each grade and the application of uniform conditioning to three variables is investigated, ie for the first approach NSR is used as the main variable. The second approach considers copper as the main variable. In the case of multiple domains the procedure used to apply the technique to process mixed panels is clarified and recommendations are made.

Sep 26, 2011

By D Yan, D Connelly

Beneficiation of magnetite is an integral part of the future of iron ore processing. Historically, the focus of Western Australian producers has been on exporting direct shipping ore (DSO) namely haematite. The future for new DSO resources is limited so companies are changing their emphasis into processing the very large, undeveloped magnetite ores in Western Australia (WA), using beneficiation to produce shippable magnetite concentrates. These magnetite resources require higher cost processing techniques such as fine grinding and beneficiation to produce saleable concentrates. This distinct difference, from the DSO ores, has led to the development of a number of new technologies. This paper reviews: the different techniques used for magnetite beneficiation and provides some case studies in the WA industry; the use of mineral liberation analysis (MLA) to describe the nature, grain size, occurrence and associations of the mineralisation;the consideration of coarse cobbing as a critical upgrading; the application of high pressure grinding rolls (HPGR) to save energy; how the field of magnetic separation has resulted in new machines with higher field strength (SLon Separators); ultra fine grinding requirements of magnetite concentrates; andthe application of reverse flotation to reduce silica in the concentrates.

Jan 1, 2009

By Kepplinger W

The KR Process is a joint development by VOEST-ALPINE, Austria and its subsidiary company KORF ENGINEERING, Germany. This new technology allows production of hot metal on the basis of non-coking coal. The KR Process is based on the idea of separating the process steps realized in the blast furnace (generation of reduction gas, reduction of iron oxide and melting of the reduced iron) and including coking of coal. These reactions are carried out in two reactors: - the melter gasifier, where non- coking coal is coked and gasified into a high quality reduction gas and hot prereduced iron is melted. - the reduction furnace, where iron oxide is reduced by the reduction gas generated in the melter gasifier and discharged in a hot state. In order to prove the process a pilot plant has been set up in Kehl/ Rhine in 1981 with a nominal capacity of 60.000 tpy.

Jan 1, 1986

By Thompson M

The humble gabion basket is to mine development what the light bulb and safety pin are to eir-ryday life. Gabions provide a flexible, easy to assemble and cost efficient solution for "101" mine and civil engineering development applications.In some instances gabion baskets are still efficiently in use after many years of faithful, maintenance-free service. In other situations, the baskets have been demolished or made redundant within days, either having served their temporary usefulness or negligently destroyed by the operator of heavy equipment. Either way, the gabion basket must surely rate among the top 10 cost efficient engineering construction materials.

Jan 1, 1994

By D Henderson, M Germain

The beneficiation of iron ore deposits to yield haematite and magnetite concentrates for steel making processes typically require the use of one or a combination of wet processing techniques based on gravity, magnetic or froth flotation processes. With the need for more cost-effective technologies with a lower water demand, a re-examination of dry processing techniques has been initiated. For example, a dry processing capability may offer an advantage where suitable quality and quantity of process water hinders the development of a particular resource. This paper describes recent laboratory test work for the production of high grade concentrates using dry electrostatic techniques for -300 ¦m haematite and magnetite ores and compares them with magnetic separation techniques.

Jan 1, 2009

By P Kirsch, P Jagals, D Viswanathan, J Shandro, R LaBouchardiere

The planning, design and operation of mines must include the development of positive environmental, community and land-use benefits if it is to achieve good corporate social responsibility and minimise detrimental impacts throughout the life of the mine. Life-of-mine (LOM) planning should, therefore, consider conducting mining activities in the best socially, environmentally and economically acceptable manner, from the commencement of exploration to post-closure of the mine. Current knowledge of LOM activities in relation to public health (life-of-community, or LOC) impacts neither fully captures the full suite of human health and well-being impacts, nor comprehensively informs society on these issues. This knowledge gap is becoming more apparent as public antipathy is increasing towards mining activities within Australia, Canada and globally. The purpose of this paper is to present preliminary and informative results of a literature review to gain insight into the extent of available public health and well-being knowledge associated with mining development. LOM development must also benefit the LOC, in that it must aim to minimise detrimental impacts, and maximise beneficial (including health) impacts on all associated communities. Health planning and programing for mitigation of potential adverse health impacts of mining should extend beyond the scope of work-related injury and illness (resulting from chronic exposure to harmful substances, infectious and lifestyle illnesses), to the health and well-being of workersÆ families and extended associated communities. By mapping the available but rather scarce literature on LOC areas to recognised LOM stages, this review found shortcomings and imbalances regarding research reporting on mining and its health-related impacts in the worker-to-community continuum.CITATION:Kirsch, P, Viswanathan, D, LaBouchardiere, R, Shandro, J and Jagals, P, 2012. Health impacts extend from the life of a mine to the life of a community - Knowledge gaps, in Proceedings Life-of-Mine 2012 , pp 161-168 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012

By I Canbulat, A Mcquillan

This paper presents a parametric analysis showing the impact of virgin in situ stresses on a shallow (less than 100 to 150 m) high slope in a jointed sedimentary rock environment. Slope stability is assessed at varying ratios of slope orientation and horizontal stresses. The results of this study indicate stress conditions should be included in stability assessments of excavated slopes, particularly where structure is orientated perpendicular to the direction of horizontal stress. Some consideration of stress state is applied in deep open cut pits (eg those with planned excavations of 400–1200 m) (Myrvang et al, 1993; Stacey et al, 2003; de Bruyn et al, 2014; Kozyrev et al, 2015). Dodd and Anderson (1972), Kalkani and Piteau (1976), Lee (1978), Coulthard et al (1992), Noorani et al (2011) have studied the effect or horizontal stress and its impact on slope stability, showing that tensile stresses tend to develop at the crest of the slope, with larger tensile zones for higher horizonal stresses and steeper slope angles (Stacey, 1970, 1973; Sjoberg, 2013). However, the consideration of virgin stresses on shallow slope stability is less frequent (Lynch et al, 2005; Dight, 2006; Lucas, 2006; Sjoberg, 2013). This has led many geotechnical engineers to believe the impact of virgin in situ stresses on open cut slope stability is minimal and not worth time or consideration in modelling, or their effects on slope stability are still poorly understood (Stacey et al, 2003; Sjoberg, 2013).

Nov 29, 2022

By H Chalcraft, T D. Mullen

Conditions encountered at a recently completed brownfields mining project provided valuable insight into, and development of, techniques for working in and around known underground mining voids in an open cut environment. The careful application of underground blasting principles to a pit environment and successful excavation whilst maintaining appropriate stand-off distances were two primary areas of innovation enabling the success of the project.Mary Mac Hill is a gold deposit situated less than 2 km south-west of the town of Laverton, Western Australia. It is owned and mined by Crescent Gold Limited. Previous underground mining by various other mining companies has left an extensive network of underground horizontal development, subvertical stopes and shafts, some of which daylighted at surface. This was identified as potentially posing substantial risks, which would prevent the application of conventional mining methods. Two major stopes were located under a hard banded iron ridge topped by a peak of cap, connected variously by narrow drives and vertical development. Due to the proximity of the first of these stopes to the surface, its dimensions and governed by procedures and advice provided by externally engaged engineers, Crescent Gold could not access the area of the ridge immediately overlying the stope using conventional open cut mining methods. This was the first of many hurdles surmounted in mining this deposit.The following report outlines how the challenges this geometrically complex deposit presented. Solving these problems enabled the team to mine the contained gold ore to a completed design, without subjecting personnel or mining equipment to harm due to a void breach incident. This paper outlines the numerous complications and difficulties Mary Mac Hill posed and explains the strategies developed to overcome them. The report also presents technical mass blasting details explaining two of the critical crown pillar blasts.CITATION:Mullen, T D and Chalcraft, H, 2012. Mary Mac Hill - The challenges and strategies of successful open cut mining: A complex underground gold deposit riddled with a network of complicated voids, in Proceedings Eighth Open Pit OperatorsÆ Conference , pp 89-96 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 18, 2012

Professional engineers of today require a wide array of experience and knowledge. It is true that commonly engineering degrees do teach the technical requirements well, but do fall short in the way of teaching other non-technical issues of professionalism to the student. Today calls for an engineer who does not only have a high standard of the technical knowledge required for their degree, but also has a broad range of experience in areas that are becoming increasingly important in engineering. The importance of social responsibility, liability and interpersonal relations is high. Through the face of the changing world, it has become clear that there is a need for a new type of engineer, who has a broad range of expertise, as well as the typical technical abilities required. This paper will outline these non-technical issues and propose ways of combining these ideas into the mainstream engineering degree.

Jan 1, 2004

By P A. Grossman, J H. Rubinstein, M Brazil, K G. Sirinanda

To date, the scheduling and access design of an underground mine have only been considered as two separate optimisation problems. First, access to the mine is designed and then the scheduling is completed. One drawback of this approach is that the costs of access construction fail to be reflected in the net present value (NPV) calculation. In this paper, designing the access and scheduling its construction are formulated as a single optimisation problem.The underground mine access construction process can be classified according to the number of faces being developed concurrently. An underground mine with a single decline branching at a junction point into two declines is considered. After construction reaches the junction, the two faces of the decline can be constructed sequentially or concurrently.This paper proposes an efficient algorithm for optimally locating a junction point to maximise the NPV where two faces are being developed concurrently. The NPV is defined by taking the locations of orebodies and their values, decline construction costs, decline development rate and discount rate into account. The variation of the NPV and the optimal locations of the junction point for one and two concurrent development faces for a range of discount rates are discussed and compared. The proposed algorithm is applied in a simulated case study based on hypothetical values for an underground mine.CITATION:Sirinanda, K G, Brazil, M, Grossman, P A, Rubinstein, J H and Thomas, D A, 2014. Strategic underground mine access design to maximise the net present value, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014 , pp 235–242 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

By H Khoshrou, A Siamaki

Blast designs can have productive and non-productive impacts on downstream stages, mine productivity and operating costs. On the other hand, ground vibration, fragmentation, and back break caused by blasting impose damage and financial penalties and which must be controlled by blast design. One of the significant variables in blast design is the burden. In this study, the potentials of artificial neural network are investigated in prediction of burden in the Sungun copper open-pit mine. Input data were assembled through 18 blasting blocks according to different levels and experimental geomechanical investigation. To construct the model blastability index, uniaxial compression strength, hole diameter, specific weight of rock, rock quality designation and cohesion strength are taken as input parameters, whereas, burden is considered as an output parameter. Mean square error was used as the performance function and back propagation algorithm as the training function, containing four hidden layers and 14 data sets. Four sets of data were used to make sure that correct training had been carried out. This produced the coefficient correlation of 0.662.

Sep 26, 2011

By A T. Spathis, K E. Leslie, K R. Blay

Many open pit mining operations seek to control blasting-related movement of ore and waste to minimise loss and dilution. Tracking the movement of ore boundaries can result in the maximisation of ore recovery and minimisation of waste sent to the mill, thereby optimising the economic performance of the operation.A novel solution for tracking the ore–waste boundary location before and after a blast uses subsurface markers placed along the boundary with all measurements and scans conducted remotely from the blast block. Upon system activation, user-operated equipment on the surface determines the three-dimensional (3D) location of the subsurface markers.The patented system concept combines two electromagnetic mechanisms, magnetic positioning and radio frequency through-rock communications to enable remote battery-powered markers, buried within the rock to be accurately located in 3D space.Field trials at a quarry have demonstrated the system can comfortably handle over 100 subsurface markers with a complete scan, including set-up, taking less than an hour. Location accuracy for each marker in 3D space is better than 0.5 m at a range up to 50 m from the magnetic source, and the system has an overall operational range in excess of 75 m.CITATION:Blay, K R, Spathis, A T and Leslie, K E, 2015. A remote, rapid and accurate three-dimensional ore waste boundary tracking system, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 297–306 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By A Chadwick, J de Ross, C Adams

Imagine a æshinyÆ new mine, $1 B in the bank and record commodity prices. So how does a company and its management team create enough tension to maximise profit and to establish a culture that can weather the good and bad times?That was exactly the situation the team at OZ MineralsÆ world class Prominent Hill mine in South Australia faced in 2009.Three years later, the harder times have come - lower though still healthy commodity prices, rising industry costs, fierce competition for talent, geological and technical issues (common to developing mines). However, the company was able to maximise profit during the good times and equip the culture to deal with the tougher times with minimal turnover.Through the combination of simple systems and processes, people development, application of commercial technical acumen and a combination of yin and yang leadership, OZ Minerals has achieved something quite rare - sustainable continuous improvement.The journey started with a vision. The EGM Operations created the æsparkÆ. The dream was to create a æfranchise mineÆ that could be rolled out to new mines and acquisitions as the company grew. However, the real leadership came from his lieutenants who provided the important yin and yang. The GM commercial provided the tools, processes, systems and the bottom line focus. The GM operations focused on culture, leadership, training and sustainability. This powerful combination (along with some good old persistence) was able to create the critical mass required to make continuous improvement go æviralÆ.This paper explores this unique case to uncover the essential ingredients that were created and mixed together. It will touch on the key human, technical and system elements that helped achieve significant improvements in plant recoveries, mine throughput and operational efficiencies, while overcoming human capacity, geotechnical and contractual challenges.CITATION:de Ross, J, Chadwick, A and Adams, C, 2012. How to create a perfect storm, in Proceedings International Mine Management 2012, pp 239-250 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 20, 2012

By V Louchnikov

Ever increasing depth of mineral extraction presents a challenging environment for hard rock underground mines. High in situ stresses and associated seismicity with potential rock burst hazards are the major decisive factors contributing to the choice of a ground support regime. Conventional ground support systems, designed primarily for static loads, are not always capable of providing safe working conditions for underground personnel in seismically active mines. Systems specifically developed to resist dynamic loading and allowing for larger deformations are therefore preferred alternatives. High-tensile chain-link mesh has a proven record of successful use in open cut operations in various rockfall barrier installations due to its high energy absorption capacity. It has also been used in underground operations in various parts of the world. Its application in Australian underground mining, however, is limited due to the high labour intensity. This paper describes a method of mechanised installation of a chain-link mesh as trialled at Golden Grove, a base metals underground mine in Western Australia. A purpose-built mechanised roll mesh handler, developed in Australia, was used in this trial. The handler is compatible with all standard multi-boom underground drill rigs and is operated utilising the hydraulic circuit normally used for the feed arrangement.A number of operational benefits have been identified during the trial, the main two being:•improved safety of underground personnel due to the reduced amount of manual handling, and•increased productivity due to the decreased cycle time (the trial suggests a 40 - 50 per cent reduction in time over the weld mesh installation method).Although the energy-absorbing mesh combined with yielding rock bolts is a ground support system of choice for rock burst prone conditions, the operational upsides recognised during the trial imply that this product can also be competitively used in less demanding ground conditions where customarily weld mesh or shotcrete are used as a primary surface support.

Mar 21, 2011

By Hein K. A A

The Mt Todd Gold Project is located 42 km northwest of the township of Katherine within the Northern Territory of Australia. It is situated in the southeastern portion of the Pine Creek Geosyncline. The Batman gold deposit, the largest of several deposits at Mt Todd, hosts an identified mineral resource of 92.9 million tonnes (Mt) grading 1.4 grams/tonne (g/t) as at 31 December 1993. Host rocks at Batman are assigned to the Early Proterozoic Burrell Creek Formation, comprising greywacke and siltstone interbedded with shale. Gold mineralisation is associated with a very broad zone of sheeted and stockwork quartz-sulphide veins that occupy a corridor of intense brittle fracture and faulting. A conceptual model of formation involves the dilation of joints and micro-faults within overlying sediments during sinistral movement along a basement shear zone. Synchronous granite intrusion generated convective circulation of crustal fluids through the sedimentary pile resulting in the formation of auriferous quartz veins within favourable structures. The Batman zone of mineralisation is not directly related to fold structures which typify several other major gold deposits within the Pine Creek Geosyncline.

Jan 1, 1994

By J Battista, J Grace, I Brunton

The need to better understand and develop strategies to improve instantaneous shovel productivity at the Cadia Hill Open Pit Mine (CHM) instigated the development of the æShot to ShovelÆ project. This project has involved the implementation of a drill and blast (D&B) information management system to capture current and future experience. Equally important has been the manual monitoring of shovel productivity and direct use and analysis of high precision GPS and productivity data logged by ModularÆs Dispatch System. The analysis of this type of data was facilitated with the application of GIS based software (ie MapInfo). This has shown to be a powerful medium to display, interpret and assess this type of spatial information on a blast-by-blast basis. Cadia HillÆs well-defined D&B processes supplemented with the application of the above systems are providing a unique capability to assess and better understand the impact of both muckpile conditions and operator proficiency on instantaneous loading productivity. This is facilitating the definition of appropriate optimisation strategies in both drilling and blasting and operator proficiency training. This paper gives a summary of the work conducted in the æShot to ShovelÆ project, describes the engineering tools being implemented and discusses preliminary findings and their practical implications.

Jan 1, 2004