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Jan 1, 2004

By D E. Gadd

Since October 1972, New Zealand Steel Mining Ltd has loaded around ten million tonnes of ironsand concentrate from single-point mooring buoys located off-shore at Taharoa on the west coast of the North Island of New Zealand. Before the first off-shore loading system was installed a considerable research effort was applied to proving the slurry loading technique. Subsequently the system has been expanded and a new buoy, pipelines and pumping system were installed in early 1978. Since then 110 000 DWT class ore carriers have been loaded at rates of around 2600 tonnes per hour through twin submarine pipelines. This paper reviews the operation of the ship loading system and attempts to answer the question: 'If the Taharoa operation were to be planned in 1980, would the same research spending be necessary or have published research results since, made such practical tests unnecessary?'

Jan 1, 1980

Bioleaching Metals from Waste Printed Circuit Boards and the Shapes of Microorganisms

Sep 13, 2010

By D Lautier, A A. Ndiaye, A Galli

Traditionally gold producers had built up hedge books to protect themselves against adverse changes in the commodity price, but diversified mining groups were staunchly opposed to hedging in any shape or form. The situation has evolved over the past few years. Gold miners have been reducing the size of their hedge books in line with the rising gold price. Commentators have talked about ædouble-digit dehedgingÆ and have suggested that this is the final countdown for gold hedge books. It sounded as if the era of hedging by mining companies was drawing to a close. But as appearances can sometimes be misleading, we decided to find out what mining companies were actually doing. Companies listed on stock exchanges are now obliged to give details of their derivatives holdings in their annual reports. Two or three years ago there was no such obligation. Our reality check was based on the latest annual report issued by three multinational mining groups; two with diametrically opposed views on hedging (Rio Tinto and Barrick) and the third (BHP Billiton) with an intermediate position. This snapshot of their derivative positions at a point in time revealed that Barrick and BHP Billiton have substantial derivatives positions (worth billions of dollars) to protect against adverse changes in foreign exchange rates and interest rates. Moreover Barrick has recently started hedging against increases in fuel prices. Despite its opposition to hedging, Rio Tinto has derivative positions worth several hundred million dollars, but these are primarily a legacy from various mergers and acquisitions over recent years or were entered into as a condition of project financing. Lastly we were surprised to discover that Barrick was holding asset-backed commercial paper (ABCP). So the idea that mining companies donÆt hedge their risks is just another urban myth.

Jan 1, 2009

By D Chalmers

After the sustained use of the GAG (Górniczy Agregat Gaśniczy) engine at a Queensland coalmine, it has raised questions as to its effectiveness as a remote firefighting tool. All firefighting apparatus have advantages and limitations, however the deployment of any apparatus must be based on its likelihood to succeed and effectively extinguish the fire or bring it under control. A recent study conducted for ACARP by researchers at UNSW has highlighted that there is more to be learned about the GAG. As coalmines are mining at greater depths and fan pressures are much greater than they were when the GAG was introduced, deploying the GAG may be a total waste ofresources and may place operators at greater risk. When the GAG unit is positioned on the surface of the mine, the pressure it generates has to overcome buoyancy of the exhaust gases and the frictional resistance of the borehole and part of the mine circuit. Buoyancy in deeper holes can lead to the GAG pressure relief system opening, venting out the products to the atmosphere without delivering any product to the mine workings. Additionally, frictional resistance is a function of distance. Deeper holes will have a greater frictional resistance than shallow holes. Delivering sufficient products from the unit will be limited by the available pressure that has to overcome the buoyancy, and increased mine resistance thatconsumes any residual pressure. By documenting the limitations of this unit it will enable better decisions to combat a fire or spontaneous combustion event.

Oct 12, 2022

By P Cooper

Continuous improvement using six sigma methodologies commonly follows the DMAIC methodology of define, measure, analyse, improve and control. A key requirement in the use of this approach is to ensure that data is trusted, validated and contextual. In today’s production environments it is common to find disparate technology comprising the system architecture and highly customised interfaces between the various technology layers. This complexity often leads to inaccurate data presented at the operations management layer or worse, data that is not trusted. Identifying defects and making corrective actions cannot be efficiently carried out unless trusteddata can be easily obtained with a production context. It is also common to find that disparate systems of this nature present information in multiple ways and through multiple presentation systems. This paper discusses how the use of web-based technologies in an integrated technology stack can aid the accessibility, accuracy and trust of data used in decision-making and also how a unified visualisation environment can lead to greater operator efficiency.

Jul 11, 2011

Declining metal prices over the last few years have reduced the number of new metallurgical plants being built and limited opportunities for introducing new processes. However, technological advances are still being made. With increasing economic pressures, the emphasis is now on reducing unit costs by making equipment larger and through use of technologies with lower operating costs. This trend can be seen in the increasing size of grinding mills and flotation cells used in recent plant designs and in the adoption of HPGR crushing as an alternative to SAG milling. Few new technologies achieve widespread introduction until there are clear economic or operational drivers. These might currently include: ò          increasingly stringent environmental standards; ò          availability of exotic materials for equipment construction; ò          increasingly sophisticated instrumentation and control systems; ò          the need to treat increasingly refractory oretypes; and ò          the length of supply routes to many new plants. As a result of these drivers, a number of new and revitalised technologies will get increasing prominence in the design of new operations, such as: ò          use of ultrafine milling equipment such as MIM's Isamill for treatment of refractory gold ore concentrates; ò          use of thiourea as an alternative for cyanide in sensitive locations; ò          novel hydrometallurgical routes for treating base metal ores in remote locations; ò          paste thickening for tailings deposition; and intensive cyanidation of gravity concentrate

Jan 1, 2000

By B Ganesia, H Sahupala

PT Freeport Indonesia is a copper-gold mine operation located in West Papua, Indonesia about 3500 km east of Jakarta. Current ore production is about 270 000 tpd, of which 30 000 tpd comes from underground. In the future, the production from underground will be gradually increased to reach a maximum of 115 000 tpd, as the Grasberg open pit production decreases. The current and future challenge for PT Freeport Indonesia is to fill the quota of underground miners, as Indonesia does not have a long culture of underground work. At present, there are only three active underground mines in Indonesia. The lack of underground skilled labour incited the company to develop its own skilled workforce. In the mean time, to overcome the shortage of personnel, the underground management had to find a way to improve the productivity. Since 21 May 1998, PT Freeport Indonesia Underground Mine has operated with the new roster of two rotating shifts a day, 11 hours per shift. The previous schedule consisted of three nine-hour shifts per day, six days a week, for a total of 26 working days in a month. This change was intended to increase the productivity of the miners. With the previous roster, studies determined that the effective working time was only seven hours per shift. The new roster produces an improvement of effective working hours to about nine hours per shift. As a result, total production has increased by 33 per cent and the utilisation of production equipment has increased by 16.5 per cent. This paper describes the background of the decision to change the work schedule, the study carried out to evaluate the benefits and drawbacks of the new shift roster, the challenges, and then compares the results for various parameters between the old schedule and the new one.

Jan 1, 2002

By X Li, J Wang, D Liu, Y Liu, K Hu

"Since the adoption of open-door policy 30 years ago, rapid economic growth has resulted in serious resource depletion and environmental destruction, especially in mining areas. As an urgent response to this situation, the central government and the Ministry of Land and Resources (MLR) have adjusted policies with concrete and realistic actions for halting this trend of non-sustainable mining activities in China. æGreen Mine CampaignÆ is one of the actions implemented. In 2010, MLR announced the æGreen Mine CampaignÆ, in which existing and new mines will be evaluated against the æGreen Mine Construction StandardsÆ and certified as æGreen MineÆ if complying with these standards. The standards cover five key aspects: the considerations of science-supported resource exploitation efficient resource utilisation standardised management environmental friendliness harmonious community relationship.Every year, MLR reviews ægreen minesÆ from all provinces. Thirty seven mines, including coal, metal, non-metal, gold, chemical industry and building materials mines, passed the review and were certified as green mines in 2010. In 2011, 187 out of 194 mines that participated in the review were certified as ægreen minesÆ. These mines are viewed as good examples of sustainable mining development in China.CITATION:Liu, Y, Hu, K, Li, X, Liu, Y, Liu, D and Wang, J, 2012. The green mine campaign and sustainable mining in China, in Proceedings Life-of-Mine 2012, pp 339-342 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 10, 2012

By B D. Saffron

In 1983, open cut coal mining operations were suspended at the Tent Mountain coalmine, located in Alberta, Canada in an area called Crowsnest Pass. Montem Resources (‘Montem’), an Australian mining company, purchased the asset in 2016. They conducted several drilling campaigns and undertook environmental monitoring with the intent to restart operations. In 2020, Montem completed a Definitive Feasibility Study, which indicated a mine life of more than 14 years.

Aug 2, 2023

By M Recabarren, A Echeverria, J Ronda, J I. Guzman, R Dodds, G Juarez, E Vila-Echague

A strategic mine plan is a fundamental part of any mining operation. It must provide a realistic and operative extraction and processing schedule, and yield the highest value for the business. For open pit mines, the problem can be modelled as a set of blocks representing the deposit, for each of which we need to decide if it is going to be mined, if so, when and where it will be sent (process, stock or dump).This problem can be proven to be of NP-Hard complexity. The traditional approach used by mining engineers to tackle this complexity is to separate the problem into more tractable components, solving each separately. The first step is to use the Lerchs-Grossman (LG) algorithm to obtain the final pit limit, as well as a set of optimised pit shells (nested pits), using different input prices. Then, using this input, operational phases are designed. Third, the set of phases can be used as an input for a phase-bench style optimisation, usually using a mathematical programming-based algorithm.There are, however, several problems with this approach. First, dividing the problem into simpler parts has the consequence that any compromises made at early stages limit the potential value left for the following steps. Second, LG is a static algorithm, with no concept of the time-value of money, capacity limits, opportunity costs, etc. Phase design is essentially a manual step, for which nested pits provide insufficient information in practice, and therefore the quality of the result in terms of potential net present value (NPV) depends strongly on the experience and expertise of the designer. This means that key input data such as commodity prices, different processes capacities and mine movement limits, are considered only at scheduling, when there is little room for optimisation. This sequential approach limits the potential value in each step, where a simplified problem is addressed, instead of addressing the real, and more complex problem, which is dynamic and should be solved as a whole.We present in this paper an algorithm, and its commercial software implementation, that addresses the dynamic problem as a whole, simultaneously and automatically creating a high-value strategic mine plan that adheres to basic operational constraints, determining dynamic cut-off grades and delivering a set of phases which can serve as a much stronger guide than nested pits for the final design. We discuss some of the key elements of the algorithm and propose a new methodology for strategic mine planning, where phase design dynamically responds to mining strategy definition. Results using different mining and operational parameters on a fictitious copper deposit are used as a demonstrative example.CITATION:Juarez, G, Dodds, R, Echeverria, A, Guzman, J I, Recabarren, M, Ronda, J and Vila-Echague, E, 2014. Open pit strategic mine planning with automatic phase generation, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014 , pp 147–154 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

By K Zunica, A R. Penney

The principles of three-dimensional geological modelling are well understood and routinely used. Sample data is collated and geostatistical tools used to ensure that sample data is suitable for its end use, which is typically a block model that is appropriate for mine planning. What has become increasingly apparent is that physical rock properties and geotechnical parameters need to be incorporated into the three-dimensional geological model to create an integrated mine model.The approach to the collection of geotechnical information is not as highly prescribed and controlled as collection of geological data. Commonly, the geotechnical data set is incomplete and inconsistent, with little consideration of what the end use will be by those collecting the data, or how the geotechnical data might relate to the geological data. In some cases, specific geotechnical investigation programs are completed, yet correlation between those programs and previously collected data is rarely undertaken to the same level of diligence as found in the geology field.There are some obstacles that need to be considered when attempting to incorporate geological parameters, such as grade, lithology, and geological domains with geotechnical information such as rock quality designation (RQD), rock mass rating (RMR), rock strength, and geotechnical domains into the same three-dimensional block model. Interpolation or geostatistical estimation methods used for grade estimates might not be appropriate for many components in rock characterisation, particularly search geometries. A number of examples are provided to illustrate issues underlying some of the data collection procedures, and their effects on three-dimensional geotechnical modelling.The example presented attempts to highlight generally observed shortcomings in the collection of geotechnical information, parameters which need to be considered when combining geological and geotechnical data into the same model, and the benefits of having a combined block model from the beginning of a project.CITATION:Zunica, K and Penney, A R, 2014. Integration of geological and geotechnical data for three-dimensional modelling, in Proceedings Ninth International Mining Geology Conference 2014 , pp 291–298 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

By A Asadov, D Nair

This paper discusses the determination of the percentage of crystalline material in a natural silica deposit which would be considered harmful to health (<10 ¦m). A sample of the natural silica material was recovered and split into a number of subsamples. Samples were sieved using a conventional dry sieve to remove material >300 ¦m before testing. Particle size analyses of the fine fraction showed 75 per cent of the material was below 10 ¦m. Initially XRD and XPS were run on the samples to determine the minerals and composition of the sample. The XRD revealed strong quartz peaks and smaller tridymite peaks with a high amorphous background. The XPS indicated traces of iron, titanium and carbon with dominant silicon and oxygen peaks. The structure of the sample was investigated using the SEM. It was apparent that there were a number of larger quartz crystals (>30 ¦m) with a mix of amorphous and crystalline in the finer fraction. It was also observed that amorphous material was attached to the surface of the crystals. In order to determine the percentage of crystalline quartz a known amount of quartz was added to the sample incrementally. On each addition an XRD scan was performed and the area under the peaks recorded. Back analysis of these peaks with an assumed percentage of crystalline material in the original sample gave a crystalline content of 30 per cent. The quantity at the respirable fraction was estimated to be 18.7 per cent.

Jan 1, 2003

By P Edmondson, S Narendranathan, S Setchell

The complexities of mining in current economic conditions, where ore extraction schedules are varied on a weekly basis so as to ensure constant supply to the process plant, can result in a number of scenarios that pose geotechnical challenges. This paper presents a case study where alterations in the mining schedule of a particular mine resulted in the necessity to mine under a large uncompacted embankment, ie integrated tailings and mine waste landform. To effectively ensure that ore recovery was maximised, a well-designed slope monitoring system to evaluate design performance and to provide timely warning of impending failures was imperative. In order for an appropriate slope monitoring strategy to be developed, a thorough understanding of the potential slope failure mechanisms, capabilities and limitations of available monitoring techniques is required. Communication of the monitoring results and response strategy to alarms generated by monitoring systems must also be carefully considered to maximise effectiveness. The results of preliminary stability modelling can be used to guide the design of a monitoring system, which in turn can then generate data which can be used to iteratively refine the geotechnical model. This paper illustrates the development and implementation of a slope monitoring system and associated communication system, using a case study developed at a large iron ore open pit mine in the Pilbara region of Western Australia.CITATION:Narendranathan, S, Lee, E C, Setchell, S and Edmondson, P, 2015. Modelling of an integrated waste storage facility, in Proceedings Tailings and Mine Waste Management for the 21st Century , pp 183–190 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 27, 2015

By H Mischo, M Ferber, M Donner, B Jung, S Grehl, A Dietze

Mobile robots have been making impressive inroads in a variety of domains. Within the Mining-RoX project, Technical University Bergakademie Freiberg is exploring a further frontier for mobile and autonomous robots: underground mines. The potential benefits of mobile robots in underground mining are plentiful as underground mines are strenuous and potentially dangerous working environments for humans. A higher degree of automation, with robots either acting as helpers for human miners or even replacing all human personnel deployed underground, could help to significantly reduce mining costs. In disaster cases, rescue robots could help to find missing personnel. Unmanned mines operated by robots alone would not endanger human lives at all. Further use cases, and a particular focus of the Mining-RoX project, are mobile robots that gather sensory information of the underground mine (eg for the purpose of creating detailed 2D and 3D maps) as well as monitoring environmental conditions such as air and water quality. This paper presents the design of a prototypical mobile robot for mapping and monitoring underground mines. A generic robotic platform was extended with various 2D and 3D imaging devices as well as other sensors. First results from test runs in an underground mine are reported. Maps of two sections of the mine enhanced with localised sensor measurements were successfully created.CITATION:Grehl, S, Donner, M, Ferber, M, Dietze, A, Mischo, H and Jung, B, 2015. Mining-RoX – mobile robots in underground mining, in Proceedings Third International Future Mining Conference, pp 57–64 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 4, 2015

By S Slouka

Airborne rock dust poses serious long-term health complications to workers in the underground mining and civil environment where rock excavation is utilised. During drilling, airborne rock particles are immediately released into the breathable environment where additionally, the settled dust can be reintroduced into the air further down in production. The purpose of this study is to build a characterisation suite of dust particles such that underground operations can implement more appropriate dust suppression and mitigation techniques in accordance to pick wear. Therefore, concrete is cut to create a preliminary dust characterisation baseline, where future cutting tests will be performed on limestone and sandstone rocks.In this study, three conical pick wears (new, moderately worn, and fully worn picks) are used to generate dust from a concrete block and characteristics are statistically compared between the dusts. Airborne respirable particles are collected during cutting and deposited fine material, orparticles left on the surface of the block, are collected after cutting. The dusts are then analysed through standardised methods, field emission scanning electron microscope image capture with image analyses, and laser diffraction methods. Findings reveal that the worn pick generated thehighest concentration of respirable dust, all picks generated dust containing quartz, the three picks generally generated respirable dusts with similar particle shapes (in terms of roundness, roughness, and aspect ratio), and the worn pick generated the largest deposited fine material particles.

Oct 12, 2022

Mine planning typically involves designing an operation to uncover coal with the minimum initial costs with reclamation planning and earthworks being done as an "add on" task. The landform is too steep to remain stable, has no drainage and frequently has areas of excessive acidity or alkalinity. Extensive earthworks are required to reduce grades to an acceptable level and create a drainage system. The flexibility available to the mining engineer to alter the post mining landscape clearly depends on the mining methods. Straight dragline stripping provides virtually no flexibility. However most mining operations over the term of current ten year plans have a substantial pre-strip component. It is this pre-strip material which has the potential to reduce the final reshaping earthworks. The reshaping operation itself is subject to some flexibility with various options being available to re-grade and provide drainage. The full utilisation of this flexibility to minimise earthworks cost should be the aim of reclamation design. ACIRL's current thrust in reclamation is aimed at the integration of mine planning and reclamation earthworks. This involves gathering all environment and agricultural criteria and designing the earth works necessary to produce an acceptable final landform. A key component of our work is the use of computer aided design (CADD) for the design of spoil piles, pre-strip dumps and spoil re-shaping. This approach has been applied to a number of mine sites with earthworks operations covering hundreds of hectares and hundreds of millions of cubic metres volume. We are continuing to provide that consultancy service and at the same time are involved in the development of more sophisticated software tools to apply to reclamation design.

Jan 1, 1991

By G J. Lyman

Sampling of grain for mycotoxins is challenging in that some mycotoxins, such as Ochratoxin A (OTA), have very low permitted levels and the kernels carrying the mycotoxin may be highly localised within the bulk of the grain as ‘hot spots’. Sampling for genetically modified organisms (GMOs) can be fraught with similar problems, especially if the contamination is adventitious and random. Incremental sampling under these circumstances can be shown to lead to a high variance in the sampling result.A new design of sampler for grain and other free-flowing particulates has been developed that is effective in practically eliminating the sampling variance due to distributional heterogeneity (DH).This paper introduces the design and argues that the sampler should be free of sampling variance due to DH.CITATION:Lyman, G J, 2017. A new sampler for grain and other free-flowing particulates, in Proceedings Eighth World Conference on Sampling and Blending , pp 277–280 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By K Prendergast, P Dale, I Taylor, A J. Vigar, B Lueck

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Kainantu Project is located within the New Guinea Thrust Belt in northern Papua New Guinea. The area has a long history of exploration and production, with the discovery of alluvial gold in 1928 followed by the discovery of vein deposits of gold and copper at Kora in the 1950s and the current Irumafimpa vein gold mine. Current resources on the Kora-Irumafimpa Vein System (KIVS) stand at 1.5 Moz Au, 5 Moz Ag and 217 Mlb Cu.Mineralisation in the region includes gold, silver and copper associated with mid-Miocene age mafic to felsic intrusions. The KIVS occupies a broad north-west-trending mineralised zone more than 2.5 km long and 200 m wide, with the Kora, Eutompi and Irumafimpa veins on the western side and the Judd and Upper Kora veins on the eastern side. Economic mineralisation occurs in two closely related events occupying the same strongly structurally controlled shearing (quartz-Au-telluride veins and sulfide Au-Cu-Ag veins with free Au) and is best described as a significant intrusion-related event with both epithermal and mesothermal facets that does not appear directly related to known porphyry Cu-Au systems as seen at the surface. Significant wolframite is associated with vein quartz of a slightly older age but also occupies the same shear system.The KIVS occurs within a larger mineralised area of approximately 5 × 5 km. It has complex multiphase intrusions, breccias and diatremes that are only partly delineated by drilling and comprises multiple occurrences of Au-bearing veins and porphyry Cu-Au mineralisation. The area is considered to have high potential for extending the current resources and is being actively explored. The proposed recommencement of mining activities recognises the complexity of the KIVS and later disruptive faulting and will require tighter grade control systems, targeted mining techniques and a gravity circuit to maximise free Au recovery.CITATION:Vigar, A J, Lueck, B, Taylor, I, Prendergast, K and Dale, P, 2015. Kainantu gold-copper system, Papua New Guinea, in Proceedings PACRIM 2015 Congress, pp 601–606 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By T Wang, D Wang

Photogrammetry-based techniques supported by traditional mapping tools are more frequently used for open pit geotechnical mapping. It fundamentally involves the collection of geological, structural and rock mass data from pit batters when safe to do so. These are essential components for refining and implementing continuous improvements to geotechnical models. The geotechnical model is used to review bench performance, optimise geotechnical design parameters, interpretation and analysis of pit slope stability. This paper is a case study of implementing different pit mapping methods at Mount Carlton gold mine, North Queensland. It critically reviews the tools required, including the Brunton compass, mobile application Clino, geotechnical data mapping software CloudCompare (2015) and Sirovision software. The review compares the image precision, structural measurements and data analysis. The review also underlines mine site management philosophy for safe geotechnical data collection to identify in-pit geotechnical hazards and the mitigation of potential slope instability. Sirovision is a remote sensing system for site geology mapping and interpreting geotechnical characteristics of exposed mining faces. The system utilises off-the-shelf digital SLR cameras to capture stereo photographs of the rock face and uses the latest image processing technology to generate accurate 3D models. These 3D models are digitally analysed using computational geometry to extract unbiased and accurate geological and geotechnical data. CloudCompare processes high accuracy 3D dense cloud rock surfaces reconstructed with photogrammetry software to extract the geological planes using the FACET or Compass plugins. The major discontinuity sets can be observed and the orientation (dip/dip direction) obtained from the algorithm is accurate and reliable for geotechnical assessment, including kinematic and rock slope stability analysis.

Nov 29, 2022