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By G Bournival, Y Pan, S Ata

A custom-made set-up that measures bubble coalescence time and the thin film balance (TFB) technique were used to explore the role of residual xanthate (potassium amyl xanthate, PAX) and salt (NaCl) on the adsorption of two frothers (methyl isobutyl carbinol-MIBC, and di-propylene glycolDPG) at the air-water interface. This paper is primarily focused on the comparison of these two techniques in studying the interaction between the flotation reagents and salt emphasizing their capabilities and limits. The results from the coalescence rig showed that the presence of PAX improved the stability of bubbles in both frother solutions and led to a bubble coalescence inhibition at 50–500 ppm DPG. These measures were compared with the results from the TFB. Findings from the TFB were overall in good agreement with the bubble coalescence time, but a higher stability level was observed in thin films under the same condition. The effect of salt on the frother and PAX mixture was also explored, and the results showed an adverse impact of the salt on the interaction of frother and PAX with both techniques. However, variations were found between them in some cases. The TFB is much more sensitive to the presence of dissolved gas and oil droplets.

Aug 24, 2022

By J Robertson, D Williams, H D. Plewes

The co-mixing of tailings and waste rock involves the intimate blending of tailings and waste rock to create a new material (Co-Mix) with superior physical and hydraulic properties. The new material has a low hydraulic conductivity, low compressibility, high water retaining capacity and high shear strength. Co-mixed tailings and waste rock restrict oxygen entry and water seepage to minimise acid generation and metal leaching. When compacted, Co-Mix materials have low volume change characteristics with respect to total stress and matric suction together with high shear strength. Co-mixed tailings and waste rock may be used to construct cover systems, internal barriers and seals, confinement structures or a full depth waste repository. The theoretical properties of Co-Mix blends are investigated. The results of a laboratory program to characterise the physical and hydraulic properties of co-mixed tailings and waste rock are presented. Various ratios of tailings were blended with different waste rock materials. Hydraulic conductivity tests were conducted at confining pressures ranging between 0 and 400 kPa. The saturated hydraulic conductivity for the Co-Mix materials was found to vary between 4 + 10-5 m/s and 5 + 10-9 m/s depending on blend ratio, waste rock type and confining pressure. These results together with other physical properties show excellent hydraulic and strength characteristics can be achieved for Co-Mix materials.

Jan 1, 2003

By N Udugampola, d A. Seneviratne, X Ai, B Li

With the evolution of mining technology, wireless mesh networks using low-power, long-range technologies such as LoRa are increasingly utilised in underground mining operations. Efficient deployment of wireless nodes in such mesh networks necessitates understanding radio wave propagation behaviour in underground mines. While existing propagation models either remain theoretical or apply only to basic geometric shapes, we propose a practical approach to analyse radio wave propagation behaviour in underground mines using ray tracing simulations with reconstructed 3D models of targeted environments. Our method validated using a set of corridors as a substitute for underground mine environments, involves constructing a 3D model using SolidWorks from LiDAR scans of the environment and performing wireless transmission simulations using the MATLAB ray tracing toolkit. Our simulation model is also fine-tuned by calibrating the raytracing parameters based on real-world LoRa transmission experiments in the actual environment corresponding to the 3D model. This method offers a practical solution for optimising wireless node placement in underground mines, facilitating efficient network deployment while reducing the need for extensive physical testing of radio wave transmissions.

Sep 1, 2024

By L Ventura, M Almond

The Pueblo Viejo project in the Dominican Republic installed an innovative sample system on its reverse circulation (RC) drilling rig during commissioning and subsequent commencement of operations. As knowledge of the orebody increased with mining and plant production, cost pressures became apparent that raised questions concerning the continued use of RC drilling versus blasthole sampling for ore control.To justify the continued use of RC drilling for grade control, an in-depth study was undertaken to determine the quality of the sample and prove its value-add to the operation.To investigate the differences in sample quality, a complete bench trial was initiated across both ore pits to compare RC drill results with blasthole assays on a side-by-side basis. The results indicated that based on ore block comparison between RC and blasthole sampling, RC identified an additional 20 per cent of high-grade (+ 4.5 g/t Au) ounces.Previous work indicated that Au, Ag and Cu were all elevated in the drill fines at Pueblo Viejo (Goers and Almond, 2012). This previous test work did not consider the quantity of fines in an RC sample therefore new test work was undertaken to include particle size distribution analyses. This study would determine if the inclusion of fines in the sample was occurring and compare the quantity of fines in the sample against other sample systems and blasthole samples.Comparisons between RC samples and blasthole samples indicate that for the RC samples a range of 30–35 per cent of the sample passed 300 mesh as compared to blastholes where the range of the sample passing 300 mesh was 15–30 per cent.This paper includes a case study on the importance of accurate samples and how they have impacted throughput through the pressure oxidation process plant at Pueblo Viejo. The accurate samples provided by RC allow for improved stockpile and blending strategies, showing the importance of accurate samples to manage risk and create value, against the perception that savings can be made at the risk of poor sampling performance.CITATION:Almond, M and Ventura, L, 2017. Adding value with reverse circulation drilling at Pueblo Viejo, in Proceedings Tenth International Mining Geology Conference 2017, pp 277–284 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

A Process for the Flotation of Chrysocolla

Sep 13, 2010

By J Vann

Geometallurgy is inherently multidisciplinary and it gains its power to deliver improved outcomes for the minerals industry by bridging silos between disciplines. This cross-disciplinary approach unlocks value, identifies (and avoids) value destruction and provides a pathway to better implementation of an energy efficient and sustainable minerals industry. Despite this promise, we argue that the cross disciplinary approach also represents the greatest threat to the success of geometallurgy. Some key cross disciplinary issues identified are:Geometallurgy has so far evolved in the technical sphere, mainly by collaborations of geologists and metallurgists. Consequently, in many cases the business dimensions and value have not been incorporated. Financial and risk evaluation viewpoints need to be assimilated into the geometallurgical paradigm. In fact, until such measures are integrated into practices, the value cannot be fully demonstrated.The historical and current efforts on geometallurgy have been highly focused on improved sampling and measurement of geometallurgical properties or appropriate proxies. This work has been driven by professional and academic geologists and metallurgical engineers. It is notable that mining engineers (who are critical in the value delivery of geometallurgy through changed planning approaches) have so far been at the margins, or absent. The construction of valid three dimensional (3D) geometallurgical models raises some important organisational, mathematical and geostatistical considerations. The enhancement of resource models to account for geometallurgical aspects must be managed carefully if the full value of geometallurgical thinking is to be realised.The use of 3D geometallurgical models to change business decision making and practices is the real nub of the problem. We believe sophisticated scenario based evaluation methods are required if the potential impacts of spatial rock properties on processes further down the mining value chain are to be realistically evaluated. Such changed practices require ‘whole of value chain thinking’ to embed this change into the business in an ongoing way.Because profitable geometallurgy demands changed approaches to business decision-making and also organisation of the firm (radically changed in some cases), the senior executive viewpoint must be incorporated into the language and thinking of geometallurgy. This is unavoidable if the establishment of a geometallurgical approach to project evaluation, development and operation is to be successful and sustained.A powerful analogy for the problem faced by geometallurgy is the transformation of safety culture in the mining industry in the past 20 years. We argue that, as in the safety revolution, explicit models, cultural change and management of the ‘soft’ dimensions of the problem are pivotal to success of geometallurgy. In light of this, we propose a model (‘the Geomet Curve’) that gives a framework and pathway for geometallurgy in seven steps. The implications of this model for technical and organisational steps required at different stages are discussed.

Sep 5, 2011

By G R. Ballantyne, V Souto, K Bartram

Particle sorting allows partially liberated minerals to be separated prior to energy intensive fine grinding. Sensors select particles for separation and air, water or mechanical ejectors are used to physically deflect those selected. To achieve effective separation there has to be sufficient liberation, accurate detection and presentation of a separated monolayer of particles. These three physical constraints determine the particle size limits, the sorting technology utilised, the separation efficiency, and the throughput that can be achieved. The combination of all these factors controls the effective limits on the degree to which sorting can reduce the specific comminution requirements and increasing energy efficiency. This paper will explore two case studies: the application of sorting in base metal mining and precious metal mining.CITATION:Ballantyne, G R, Hilden, M, Bartram, K and Souto, V, 2018. Characterising energy efficiency of particle sorting, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 531–540 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By S Girard, L Rowland, V Lawson, Y Shields

Since 1948, ValeÆs Matte Separation Plant has been successfully using magnetic separation and froth flotation to separate the copper sulfide, nickel sulfide and Ni-Cu metallic alloy contained in Bessemer matte for downstream processing. Though some equipment upgrades have been performed over the years, the flow sheet has generally remained unchanged since the early 1970s. The need to improve metallurgical performance led to the trial of a scalping flotation column to produce a final copper concentrate ahead of the cleaner circuit feed to take advantage of a high degree of copper mineral liberation, reduce cleaner-recleaner circulating loads and decrease the associated loss of selectivity. Plant results indicated that 50 per cent of copper contained in the rougher concentrate could be recovered at final grade target. Results indicate that up to a 1.5 per cent increase in copper recovery to copper concentrate was achieved during the scalper trial due to a reduction in the generation of fine chalcocite which has historically been observed to report to flotation tailings due to surface contamination. Deficiencies are currently being addressed and a long-term trial is scheduled to confirm the benefits of copper scalping.CITATION:Girard, S, Rowland, L, Shields, Y and Lawson, V, 2012. Copper scalping at ValeÆs matte separation plant, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 299-308 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

The Kwademen Au deposit was discovered in 1977- 1978 following a regional geochemical survey carried out as part of a UNDP (United Nations Development Programme) and BUMIGEB (Bureau des Mines et de la Geologie du Burkina) mineral exploration programme. The climate in Burkina Faso is rather dry, with markedly seasonal rainfall averaging 800 mm pa in the Kwademen project area. The relief is low and the drainage poorly developed, so that soil sampling was preferred to stream sediment sampling. Rocks have been subjected to deep lateritic weathering, so that they are transformed into a mixture of Fe-oxides and kaolinite over depths varying between 30 and 40 m. At the regional stage, soil samples (30-40 cm depth) were collected a a 300 x 500 m grid. The Kwademen deposit was indicated by Cu, Zn, Mo and Au anomalies. Subsequently, an area of 9.2 km2 was covered by a detailed geochemical survey by soil (100 x 50 m) and auger sampling. The regional anomaly was fully confirmed, and subsequent drilling intersected mineralized ore shoots, justifying the establishment of an evaluation project led by the U.N.R.F. (United Nations Revolving Fund) in 1983- 1985.

Jan 1, 1988

By D Hunter

A production information management system (PIMS) was recently implemented at Queensland NickelÆs Yabulu Refinery. Although a strong business case was developed to justify the significant investment in PIMS some potential beneficiaries remained sceptical of the anticipated benefits. The decision to install PIMS was justified as the on-line availability of continuous production data enabled the optimisation of some crucial operations resulting in significant cost savings, improved throughput and final product quality. Furthermore the rapid access to extended historical data has allowed the cause of repeated failure of equipment to be determined. The investment is expected to pay for itself within two years and has already contributed towards significant savings. This paper focuses on some of the diverse production improvements gained and compares the anticipated benefits in the business case to those achieved. A brief outline of the phased implementation of the OSIsoft PI data historian and complementary client software at Yabulu is included, along with details of the lessons learned.

Jan 1, 2003

By C A. Fleming

Gold extraction is largely driven by mineralogical factors, which often cause gold losses to various tailings. Mineralogical factors affecting gold recovery include grain size and shape, surface coating or rimming on gold particles, the presence of cyanide or oxygen-consuming minerals or preg-robbers, the presence of slow-dissolving gold minerals and the refractory nature of submicroscopic gold. Among these factors, locking of fine gold particles in sulfide, silicate and other minerals, either as visible, fine-grained gold inclusions and/or as invisible submicroscopic gold, is by far the most common factor leading to poor gold recovery in gold ore processing. This paper discusses the mineralogical characterisation of gold lost in tailings and its metallurgical implications. The techniques used in characterising the un-recovered gold are also briefly introduced.

Jan 1, 2007

The epizonal Ag-Pb-Zn vein deposit at San Bartolome is characterised by a base-metal sulphide assemblage containing the spectacular development of interpenetrating, bladed networks of pyrrhotite which have been replaced by marcasite and pyrite. A similar assemblage displaying the same crystal habits and textures are also a diagnostic feature of the Sn and SnAg deposits ofBolivia. On this basis, it is reasonable to conclude that both deposits were formed from fluids of similar nature and origin. Although no economic accumulation of Sn is known in San Bartolome, further comparison of the geologic setting, age, mineralogy, fluid inclusion data and magmatic association of this deposit with the Bolivian systems has highlighted additional similarities consistent with a hypothesis that more extensive Sn mineralisation might exist in the San Bartolome area.

Jan 1, 1995

By A Holmgren, W Forsling

In the present study infrared attenuated total reflection (IR-ATR) was used to monitor the rate of in situ adsorption of heptyl xanthate on a layer of zinc sulfide synthesised on a germanium ATR crystal. The zinc sulfide surface was characterised using x-ray photoelectron spectroscopy (XPS). The absorbance of heptyl xanthate measured increased with increasing bulk concentration of the adsorbate up to an equilibrium plateau value corresponding to a fractional coverage of the surface sites of the substrate. For the adsorption from solutions of concentrations between 10-3 and 10-5 M, the rate of adsorption increased with increasing bulk concentration. At higher concentrations the measured absorbance should be corrected for the absorbance due to the concentration of xanthate in bulk solution. The present work provides a discussion of this correction. Assuming the adsorption stage to be rate-controlling and proportional both to the concentration of the adsorbing species in solution and unreacted surface area, a rate law governing this type of transient adsorption kinetics was derived. By means of absorbance data for the concentrations 0.1 and 0.01 mM, the rate constant of adsorption was calculated. From the initial part of a Langmuir adsorption isotherm, the absorbance at monolayer coverage and the equilibrium constant of adsorption could be estimated.

Jan 1, 2005

By C M. Côte, S Worden, K Svobodova

Mines in Queensland are transitioning to the progressive rehabilitation and closure plan (PRCP) framework. Mine operators are required to select and justify appropriate and viable post-mining land uses (PMLUs) following consideration of the surrounding landscape, community views and the objectives of local and regional planning strategies. The new approach offers opportunities for considering innovative PMLU options and collaborative use of post-closure mine assets, such as infrastructure (power, road/rail, buildings), dams and residual voids. Consideration of regional planning strategies will require a shift in thinking as mine closure is regulated and planned on an individual site basis and selection of PMLUs are commonly considered from this perspective. Planning at regional rather than site-specific scale offers strategic advantages, including the ability to align PMLU selection with the regional context and stakeholder aspirations (which could foster sustainable outcomes); address cumulative environmental and socio-economic impacts; consider options that are only viable at scale (ie across larger geographic areas); establish more extensive and connected ecological habitat corridors; reinstate larger expanses of functional agricultural land; and optimise regional resources (Hattingh, Williams and Corder, 2019). This paper presents the findings from a multidisciplinary project that identified PMLU options within Queensland’s four mining regions: the North-west Minerals Province, North Queensland, Bowen Basin and Clarence-Moreton and Surat Basin (Figure 1). To enable spatial analysis at the appropriate scale and to accommodate geographic diversity, North Queensland was divided into three geographical ‘focus areas’ – Weipa, Charters Towers and Tablelands. Delineation of the areas captured most of the mines within the wider region as well as regional characteristics and features.

Aug 2, 2023

An Evaluation of Froth Recovery Measurement Techniques

Sep 13, 2010

By K C. Runge, E Tabosa, A Jankovic

Flotation recovery in geometallurgical modelling is usually predicted based on relationships developed from batch flotation testing of different ore types. These batch flotation tests are usually performed at a constant set of operating conditions and at a fixed feed grind size P80. Usually the laboratory feed grind P80 is that which is expected to be produced in the full-scale flotation circuit for that particular ore type.Flotation recovery will be a strong function of the valuable mineral particle size distribution, with lower recovery of ultra-fines due to poor flotation kinetics, optimum recovery for the intermediate sized particles and lower recovery for the coarser particles due to poorer liberation of this fraction. This valuable mineral particle size distribution is not characterised by the solids P80 parameter alone. The proportion of material in each class will also be a function of the slope of the size distribution and the degree of preferential grinding of the valuable mineral in comparison to the total mass of the ore.This paper will demonstrate (through example) how these other size distribution parameters can change with a change in grinding technology, the size and operating conditions used in a grinding unit and the characteristics of the classification technology used in conjunction with the grinding unit. Case studies will be presented that demonstrate how this can result in these parameters being very different in laboratory testing to that produced in the full-scale comminution circuit. A rule of thumb that laboratory rod milling rather than ball milling produces a size distribution most similar to that of the full-scale grinding circuit will be challenged. These differences can result in a significant change in flotation recovery. It is therefore important to consider these parameters when developing a laboratory geometallurgical program, to enable more accurate prediction of the flotation recoveries that will be achieved in the full-scale process.CITATION:Runge, K C, Tabosa, E and Jankovic, A, 2013. Particle size distribution effects that should be considered when performing flotation geometallurgical testing, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013 , pp 335-344 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 29, 2013

In the context of sustainable development, the Minerals Council of Australia (2010) states that 'investments in minerals projects should be financially profitable, technically appropriate, environmentally sound and socially responsible'. In other words, the business of mining can only be sustained if these criteria are met.   Science and technology plays a major role in all four of these criteria. This paper will present the technology and innovation emerging from the Minerals Down Under National Research Flagship which brings together CSIRO and more than ten of Australia's leading universities to work with industry to drive efficiency, productivity and environmental performance. This work is required if the Australian minerals sector is to thrive and continue to deliver national benefit in the face of increased global competition, declining ore grades, depleting ore deposits, increasingly constrained national resources (land, energy, water and people) and changing societal expectations.   Science and technology to reduce emissions and water use, discover greenfields resources, enable deeper mining operations and transform mineral processing are described. Technology is presented as an enabler of sustainability: a means to this end but not as an end in its own right.

Jun 1, 2010

Review on Some Research Methods of Mineral Crystal Chemistry and Computer Simulation on Flotation

Sep 13, 2010

By M R. Stevens, W Mori, G B. Boswell

The Onemana prospect is located on the eastern Coromandel Peninsula, North Island, New Zealand. Systematic exploration involving surface geological mapping, geophysics, rock and soil geochemistry, reverse-circulation and diamond drilling has identified a number of important features of a fossil hydrothermal system at Onemana. This relatively intact gold mineralised system is hosted within a sequence of rhyolitic volcanics and volcaniclastics, overlain by lake sediments, sinters and hydrothermal eruption breccia. The system lies within a graben/half graben bounded by major NE-trending faults which form the approximate boundaries to hydrothermal alteration. Rock and soil geochemistry indicate a broad zone of anomalous gold, silver, arsenic, mercury and antimony. Overlapping elevated rock and soil gold anomalies indicate strongest mineralisation occurs over two zones of hydrothermal brecciation named 'Breccia Knob' and 'Western Ridge'. Geophysical data obtained from Gradient Array Resistivity and Ground Magnetics have been used to produce anomaly maps. The terrain corrected resistivity plot shows a number of well defined linear resistivity anomalies which are believed to represent large silicified and quartz veined bodies at relatively shallow depths. The strongest of these anomalies correspond with 'Breccia Knob' and 'Western Ridge'. Reverse-circulation and diamond drilling targeting these resistivity and geochemical anomalies has confirmed wide intervals of quartz veining, silicification and gold mineralisation. Petrologic data based on drill samples indicates the existence of a laterally extensive gold bearing epithermal system. Hydrothermal alteration is thought to have been caused by strongly convecting, two-phase (boiling), near-neutral chloride fluids which persisted at high temperatures (170 - 220¦C) to the paleosurface. A geological model is postulated of a large, complex, hydrothermal system developed in a shallow lake or marginal lake environment created by rifting and graben development within a recently extinct rhyolitic volcanic centre. Geothermal activity alternated between relatively quiescent periods of unrestricted fluid upflow and sinter development interspersed with violent hydrothermal eruptions caused by near surface silica capping and overpressuring above a major fluid conduit centred under 'Breccia Knob'.  Opportunities for precious metal mineralisation are evident from drilling to date. Upflow of near-neutral chloride fluids to shallow depths favours the presence of strongly mineralised stockworks at relatively shallow depths. Periodic hydrothermal eruptions would have caused fracturing and rapid depressurisation of the hydrothermal system, strongly favouring the precipitation of gold from solution both near surface and within feeder-vein systems at depth.

Jan 1, 1995

By R Wolff

One critical factor in open pit mining projects is the estimation of the recoverable reserves. The reason for this is that at the valuation stage there is a lack of information about future metal prices and production costs. Consequently, the estimation of the recoverable reserves needs to be done based on a fixed break-even cut-off grade (BECG), in which fixed expected metal prices and production costs are assumed throughout the operating life of the mine (OLM). In this paper, an alternative technique for estimating the recoverable reserves of an open pit mining project is presented and explained in detail. The main characteristic of this technique is that it estimates the recoverable reserves of the project using mining costs as reference: this is done due to the fact that mining costs are easier to model than metal prices. Another important characteristic of this technique is that it uses the uncertainty of the geology of the orebody, given by simulations of the deposit, to make final strategic decisions, such as the selection of the operating life of the mine and the optimal production rate, which minimise the risk of not achieving future production targets while maximising the upside potential of future rewards. As it will be shown, the final outcome of the proposed technique is the generation of a robust open pit design, that include cutbacks and ultimate pit limits, called the marginal open pit mine design (MOPMD). One characteristic of the MOPMD is that, at each production period, it will be characterised by their respective geological uncertainty, given as probability distributions of ore, waste and metal quantities, and by marginal economical project indicators, such as cut-off grades and metal prices, among others. The details follow in the paper.

Jan 1, 2006