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By Dodd SF

Valuation of mining companies and their underlying assets prepared by brokers' analysts are, by necessity, approximations. The reliability of the valuations is entirely proportional to the quality of available data, the reliability of forecasts and the nature of underlying commodity price assumptions. The latter is perhaps the greatest single cause of gross variations in company and asset earnings estimates and- valuations. Assumptions are often necessary regarding commodity price achievement based on commodity hedge positions. Public disclosure from listed companies provides a sound base from which to project earnings, cashflows and balance sheets. The uncommon disclosure of projected production and cost schedules often reduces the reliability of future estimates. The application of reserve and resource estimates is contentious with practitioners applying differing weightings to importance of resources in estimating mine lives (and therefore cashflow streams). Valuation methods applied in equity markets usually focus on relative value and the identification of pricing anomalies. The commonest ""rules of thumb"" applied in the valuation of mining companies (and therefore their underlying assets) is with the use of year specific price/earnings (P/E) and price/cashflow (P/CF) ratios, with low multiples suggesting undervalued assets, high multiples overvalued situations (but these rules can often be clouded by market expectations of underlying commodity price movements). Another simply applied valuation tool is to examine the examine the value placed on reserves and resources by the market. Inexpensive gold in the ground (expressed as $ of market capitalisation per ounce of reserves or resources) might indicate a buying opportunity, but the market does discount the value of gold in the ground prior to mine development and where development risk is perceived.

Jan 1, 1994

By K W. Mills, N R. P Baczynski, J Mylvaganam, D A. Prado, M F. Lee, I A. de Bruyn

"This paper presents the second part of a study of the assessment of rock stress inputs on the performance of various new mining designs at the Ok Tedi large open pit mine in Papua New Guinea. Over the years, four programs of rock stress measurement have been completed at Ok Tedi, each providing different interpretations of the in situ field stresses. Details of three of these programs and interpretations are provided in the precursor to this paper, entitled ‘Rock Stresses at Ok Tedi, Papua New Guinea’ (Lee et al, 2014).This paper explains how the various stress interpretations were utilised in the modelling of the proposed new open pit and underground mining excavations, comparing where possible their expected effects on stability. The modelled performance of three specific mine components have been discussed here as case studies, including: the below-pit drainage tunnel, as the floor of the open pit workings is mined down from 350?m above, to within just 75?m above the crown of the tunnel the stability of the 1000?m high slope of the proposed West Wall cutback the proposed sublevel open stoping extraction sequence in the Gold Coast orebody beneath the East Wall, for which only the likely ‘worst-case’ stress regime was used to assess sequencing and stability issues.The benefits of scheduling the collection of detailed rock stress measurements and other input data from a range of different sources at various stages of the projects are discussed.Alternative in situ stress models have less stability impact on open pit slopes than on underground mine excavations.CITATION:de Bruyn, I A, Baczynski, N R P, Lee, M F, Mills, K W, Mylvaganam, J, and Prado, D A, 2014. The application of rock stress inputs to stability assessments at Ok Tedi Mine, Papua New Guinea, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference, pp 43–54 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 5, 2014

By M F. Lee

Although the Mt Charlotte gold resource was discovered in 1893, it was only in 1954 that geologists correctly interpreted drill data and defined a large low-grade orebody. The mine has been a large, low-cost and profitable producer since 1962 when bulk mining commenced using cut and fill. From 1968 a combination of long hole open stoping with delayed mass blasting was used. This proved to be an excellent mining method for the large, separate subvertical orebodies. The structured but otherwise good quality rock allowed very large stopes to stand unsupported. Exceptionally large equipment, for its time, was used to efficiently mine, muck and move the ore at low-cost. The mine only just survived severe cost pressures in 1974-76, due to very low gold prices. Better gold prices in 1979 and a need to access deeper ore meant a bold commitment to sink the Cassidy Shaft and refurbish the mine to sustain future profitability. In 1997 the Sam Pearce Decline connected to the underground workings, making it profitable to mine upper level remnant ore. Mining-induced seismicity has been a feature of mining at Mt Charlotte. The main cause has been shearing on structures. A mine-wide seismic system was installed in 1994. Large seismic events have occasionally made management question whether a safe working environment can be maintained. Thorough investigations led to an understanding of the problem and development of procedures to minimise seismicity.

Jan 1, 2000

By J Tiihonen, J OÆCallaghan, T Haakana

Outotec is today capable of providing technologies, process equipment and engineering for the construction of pressure oxidation leaching (POX) plants in any location in the world. Outotec works with customers from mine to pure metal, participating in plant design from the process development phase (including test work execution/supervision) to plant commissioning and operations. Either key equipment technology packages with basic engineering or entire POX plants can be supplied.The addition of pressure oxidation equipment to OutotecÆs product portfolio adds to and complements already existing significant experience in general hydrometallurgical process and proprietary equipment design and supply.In addition to providing key pressure vessels, piping and valves to a POX plant, Outotec can offer an enhanced and proven autoclave agitation system that maximises oxygen mass transfer and utilisation. Novel energy and water recovery technology can also be tailored to a customerÆs specific needs. Importantly Outotec owns and operates extensive test work facilities and can provide test work to ensure the optimum POX flow sheet and materials of construction. Outotec ensures that best available technology (BAT) concepts are used in POX design to improve the availability of the process and minimise unpredicted shutdowns.CITATION:Tiihonen, J, Haakana, T and OÆCallaghan, J, 2013. Outotec pressure oxidation - more out of sulfide ore, in Proceedings World Gold 2013 , pp 197-206 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

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

By B Flynn, P Knights

Low-loaders or 'floats' for relocating equipment in surface mines are limited to a capacity of approximately 350 t. In the iron ore industry it is desirable to be able to rapidly relocate excavators in order to maintain production rates within appropriate quality limits. In addition, the ability to rapidly relocate heavy equipment raises the possibility of improving the quality of repairs by performing maintenance in controlled shop conditions. However, many iron ore operations operate hydraulic excavators in the 600 to 800 t range, with newly released excavator models exceeding 800 t. These excavators are too large to float using conventional technology. This paper examines the potential for using multi-bogie transporters to relocate large hydraulic excavators in surface mines. Recent innovations have seen the development of modular transporters which can be coupled together to achieve larger platform areas. When separated, and with their drive bogies neutralised, these units are able to be towed behind prime movers and relocated between mines via public roads. The potential cost savings for relocating a Terex RH170 excavator in an open pit coal mine are examined. In the first six months of 2008, the analysis showed the potential for a 38 per cent reduction in total travel time with a corresponding revenue increase of approximately $350 k. The paper recommends that a feasibility study be conducted into offering a heavy equipment relocation service within the Pilbara region.

Jan 1, 2009

By J Channell, G Phillips

"The Chesney deposit, located 4 km south-east of Cobar consists of three copper-gold rich shoots that lie within a larger, copper dominant lode. A fourth gold rich shoot is located adjacent to the main deposit. The deposit exhibits a strong structural control on mineralisation, as brittle deformation during subvertical extension provided the requisite structural traps to precipitate sulfides from solution. It is postulated that the Great Chesney Fault acted as a fluid conduit, conveying fluids to the site of orebody formation. The continual supply of fluids resulted in cyclic brittle deformation when the fluid pressure exceeded the lithostatic pressure and the tensile strength of the Great Cobar Slate.Evidence supports the hypothesis that ore deposit formation was controlled by: a supply of mineralised fluids transported along the Great Chesney Faulta suitable location for the mineralised fluids to accumulate, accommodated by vertical extension and dilation in certain locationsthe creation of suitable structural traps to capture the sulfides. These traps formed as a result of fault-valve behaviour. Understanding the controls on mineralisation enables prediction of the location of other deposits with similar emplacement history, or extensions of current deposits.CITATION:Channell, J and Phillips, G, 2014. Understanding mineralisation controls – a case study of the Chesney deposit, in Proceedings Ninth International Mining Geology Conference 2014 , pp 301–312 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Aug 18, 2014

By K Myers

Since the mid-1990s, the Chino Mine Facility (Chino) located near Silver City, New Mexico has been developing a closure plan with financial assurance to protect water quality, as required by State regulations. In February 2002, Chino and the New Mexico Environment Department (NMED) reached agreement on a closure plan; a closure cost amount of approximately $US 394 million ($A 591 million) was finalised in April 2003. Both the New Mexico Water Quality Act Regulations (1977) and the New Mexico Mining Act Regulations (1993) guided development of the closure plan and financial assurance amount. The process incorporated many years of correspondence, studies, negotiations and administrative hearings. The major technical issues focused on regrading slopes of the leach ore stockpiles and waste rock piles; cover systems; water treatment systems; and abatement of ground water contamination. The proposed financial assurance amount covers all closure costs and provides for perpetual water treatment.

Jan 1, 2003

The AusIMM is concerned about the longer tem sustainability of the minerals sector in Australasia. Our contention is that the sustainability of the sector is at risk if we do not:   ò encourage more exploration in Australasia by removing impediments and         increasing incentives; ò fund our university and research centres appropriately to increase both our   prospectivity, and our processing efficiencies; and ò manage our human resources better.   This paper will focus on how we can better manage our human resources to assist in ensuring sustainability of the sector in Australasia .   From a production point of view:   Economic output = f (Land, Labour, Capital, Environment) where Land refers to all of the natural resources used in production. As well as land itself it includes water, forest, fisheries, oil, gas and mineral deposits. Labour refers to the skills and capabilities used by humans in the production process. Capital describes all of the manufactured aids used in the process of production1. The challenge for management is to ensure maximum efficiency and effectiveness of labour in the production process whilst maintaining sustainable development.   The 1992 Rio Summit defined sustainable development as maintaining and enhancing:   ò natural capital û defined as all natural resources, both environmental and   those of traditional economic value; ò manufactured capital û made by human kind, including produced goods,     infrastructure and built environment; ò human capital û defined as the health, well being, intellectual capabilities and   spiritual welfare of individuals; and ò social capital û defined as social relations and consultations within and   between societies, their norms and functionality2.   The minerals sector in Australasia has successfully focused on the technical aspects of each of these components of sustainable development with primary attention applied to natural capital and efficient utilisation of manufactured capital. The technical aspects of human capital and social have also been addressed through an emphasis on occupational health and safety and interaction with local communities however I suggest that, to date, insufficient emphasis has been placed on labour (human capital) to maximise economic output1.   It has become increasingly common practice to identify land as natural capital, labour as human capital and capital as physical capital. That is labour has been treated as a commodity rather than an opportunity to create a comparative advantage and this will be the greatest challenge for mine management to show leadership over the next decade of the 21st Century.   This paper will outline characteristics of the sector which are relevant to the management and utilisation of labour, outline the outcomes of recent AusIMM surveys, review the reasons for the current and future anticipated skills shortages, some innovative responses to the challenges and finally, suggestions on how mine management can show leadership.

Jan 1, 2006

The Division of Minerals and Geochemistry in collaboration with three mineral exploration companies, Mawson Pacific Ltd, Ramsgate Resources Ltd and Tectonic Systems Pty Ltd commenced a two year research project to investigate the application of remote sensing techniques to exploration for mineral deposits in access of the Yilgarn Block in Western Australia. The project utilizes satellite data such as day and night imagery from the NOAA-AVHRR (National Oceanic and Atmospheric Administration - Advanced Very High Resolution Radiometer) satellite. The recent research with the imagery in the Kalgoorlie, Southern Cross and Mt Magnet regions has highlighted the advantages of the mid infra-red and the two thermal response channels of NOAA-AVHRR for geological investigations. These three channels have the spectral resolution to distinguish stratigraphic units and younger intrusive bodies, and to delineate fracture zones and shear zones associated with Proterozoic dykes. But most important is the capacity to distinguish thermal signatures from geological structure, near-surface outcrop and palaeochannels which have been covered by unconsolidated sediments. The research project applies remote sensing methods including enhanced satellite imagery optimised to the Western Australian environment. It encompasses data from both space and airborne monitoring platforms that have obsreved a significant spectral response for the classification of alteration zone lithologies. It includes the collection of multiseasonal data from areas of interest which is essential both for the understanding of thermal characteristics of important lithologies and for the extrapolation from field work investigation to potential exploration areas. No comprehensive investigation of this type has been carried out within the Yilgarn goldfields.

Jan 1, 1987

In November 1986 the Australian Minerals and Energy Council (AMEC) endorsed an "Australian Code for Reporting Identified Coal Resources and Reserves" for use by the Federal and all State Governments. Before this endorsement there were six different coal codes in use in Australia. The code is broad in nature to accommodate the wide range of coal deposits in terms of rank, quality and geological environment, that are present in Australia. In the code, Resources refer to all of the coal in situ which may have potential for use and the various categories indicate the level of confidence of the assessment. Reserves are those Resources which are planned to be mined and for which such planning has been undertaken. Only minimum guidelines are set by the code and the onus is on the estimator to state clearly the criteria used in any Assessment.

Jan 1, 1987

By M F. Gazley

The amphibolite-facies metabasaltic rocks of the Mine Mafic Package at Plutonic Gold Mine, Marymia Inlier, Western Australia, contain an estimated total endowment of 12.2 Moz of Au, which includes 4.71 Moz of past production and 2.77 Moz of reserves and resources; the remainder comprises lower-grade inventory. Over 65?000 multi-element analyses of whole-rock core and face channel samples from the underground workings of the deposit have been collected by portable X-ray fluorescence (pXRF) using a handheld Innov-X Omega pXRF unit. The analyses were performed on pulverised samples through paper bags, and were corrected using a pulverised, matrix-matched, reference standard. This method of data correction compares favourably with conventional XRF analyses performed on the same samples.A preliminary study based on pXRF analyses from a small number of drill holes found that a geochemical stratigraphy was evident in the pXRF data, and that this stratigraphy strongly controlled the location of Au mineralisation. The present study incorporates a much larger pXRF data set that samples a greater volume of diamond drill core and face channel samples and presents the data in a three-dimensional (3D) framework.This data set allows an investigation of the mineralogy of Au mineralisation with varying geochemical associations across the deposit. Historically, there has been a strong relationship identified between As and Au, which has caused issues with metallurgical performance, rendering some areas of the deposit only marginally economic. Utilising seamless data integration of the pXRF data set allows for recognition of the different styles of Au mineralisation using elemental concentrations and ratios from the multi-element analyses (Au:As, Au:As:Cu, As:Cu vs. K:V), and to visualise the distribution of these different mineralogical associations in 3D. The results of the 3D modelling and geochemical characterisation of the different styles of Au mineralisation are currently the focus of an extensive metallurgical testing program, the preliminary results of which are presented here.

Aug 22, 2011

By R Mann, R Prasad, S Vink, V Nanjappa

The level of salinity that various aquatic organisms can tolerate without incurring any adverse effects is dependent on several environmental and evolutionary factors. These factors include the relative concentrations of different types of dissolved salts in the water that makes up their habitat, the regimes to which organisms are exposed to waters of differing salinity levels (including naturally derived variations), the degree to which an organismÆs life history stages have adapted to salinity, an organismÆs ability or behaviour to avoid adverse levels of salinity and an organismÆs capacity for osmoregulation.Release of saline water into rivers of the Fitzroy catchment has created concern about the impact on aquatic organisms. Not only is salinity itself a stressor on organisms but different ionic compositions will moderate the effects. Ecotoxicology experiments were conducted using artificial saline water based on mine water chemistry using sensitive macroinvertebrates collected from the catchment, as well as a range of laboratory organisms in accordance with the ANZECC and ARMCANZ (2000) guidelines. The 95 per cent ecosystem protection value calculated from species sensitivity distribution derived from the commercial tests was estimated to be ~2.0 mS/cm. For the protection of 99 per cent of the species the salinity has to be reduced by more than 50 per cent to 0.91 mS/cm. The electrical conductivity (EC) values, derived by commercial testing and species sensitivity distribution in this study suggests that salinity contaminant trigger values previously developed using a referential approach for protection of aquatic ecosystems from saline mine water releases in the Fitzroy may be conservative.CITATION:Vink, S, Mann, R, Nanjappa, V and Prasad, R, 2013. Determining the impacts of salinity on freshwater organisms, in Proceedings Water in Mining 2013 , pp 149-154 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

By A Trench, S Ulrich, S Hagemann

A synthesis of reported All-In Sustaining Costs (AISC) for 57 Australian gold mines in the period 2014–2016 reveals for the first time the clear influence of grade upon cost performance, most evident in gold-only underground mines. Past syntheses of costs on a single quarter basis have viewed grade as potentially subordinate to other factors such as production scale, mine geometry, mineralisation style and a combination of other mining-related costs. Better understanding of the grade to cost relationship on both an individual mine and whole-of-portfolio portfolio basis is needed. Insight into the roles and trade-offs between other cost-determining factors will aid the future sustainability of the gold mining sector in Australia and assist in targeting prospects for future resource growth and development. While the overall trend is toward higher-grade mines displaying lower costs and vice versa, the grade to cost functions appear radically different between mines based on time-series data. The median cost of Australian gold production in the final quarter of 2016 was A$1081/oz. The threshold for lowest cost quartile production was A$965/oz. Underground production now dominates Australian gold output – with 71 per cent of ounces originating from operations that are either entirely underground or hybrid pit/underground mines. Scale economies are evident, with smaller mines predominately among the higher cost producers. For mines of equal grade, open pit mines are lower cost than underground operations. Reserves are modest, with a median mine life for underground operations of 4.7 years based on current production rates. Reserve additions at mines are likely constrained not only by the finite nature of mineralisation at each mine but also by the geometrical difficulty of accessing suitable drilling locations to test for reserve extensions.CITATION:Ulrich, S, Trench, A and Hagemann, S, 2017. Towards an understanding of production costs at Australia’s underground gold mines, in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 241–250 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 16, 2017

Coal mining legislation makes frequent reference to æSafety Management SystemsÆ but there is a chronic shortage of useful guidance material as to how these might be applied to hazardous exposures. Several studies have indicated that for each death that is reported as a result of an industrial æaccidentÆ, there are five deaths that caused by occupational exposures. Because the deaths from occupational exposures do not occur on site and often well after employment has ceased, they are generally unreported. Improved access to mortality data from coroners, the Australian Institute of Health and Welfare and superannuation service providers (early claims from death and total permanent disability), has given rise to some analysis of death and disability data that provides evidence that there are emerging opportunities to develop and improve safety management systems for hazardous occupational exposures. Issues explored include how safety management systems might be developed in relation to dusts and chemicals and other hazardous exposures to ensure the risk of disorders with long latency periods are reliably assessed and the exposures effectively managed. The current standards and guidelines which refer to safety management systems in general or to management of exposure related hazards are examined. Many standards are based on dose-response studies that provide for an acceptable percentage of workers to suffer adverse health outcomes. An alternative management system might be to apply dose-response relations to health surveillance to identify æat riskÆ individuals and effectively manage health and related safety risk at an early stage.

Jan 1, 2005

By J Rutter, E Amini, D La Rosa, N Beaton, M Scott, F Faramarz, L Keeney

Anglo American’s Los Bronces copper mine in Chile has been conducting detailed assessments investigating value adding options for their asset. The mine has conducted several detailed Mine-to- Mill and Grade Engineering studies to investigate increased throughput and head grade and to quantifying the impact of these approaches across the life of mine. CRC ORE has two key technologies namely Grade Engineering and the Integrated Extraction Simulator. These two technology suites have been combined to understand the technological landscape and associated value drivers suitable for application at Los Bronces. Detailed ore characterisation test work was conducted to:  measure and spatially model the propensity of ores to naturally deport and  develop customised blast models for Mine-to-Mill and Grade Engineering evaluation The outputs of this work were utilised to develop a block model populated with a range on new Grade Engineering and blasting parameters suitable for scenario analysis. To facilitate scenario analysis a high-fidelity value chain model of the Los Bronces operation from blasting to concentrate production was built in IES. IES was combined with sophisticated analytical tools such as Neural Networks to develop and reconcile a fully integrated value chain. The value chain model made it possible to simulate in IES all available blocks in the block model to predict throughput and grade changes for different strategic scenarios. The scenario analysis was run across 24 strategic combinations of Mine-to-Mill and Grade Engineering and comprised several million simulations. The scenarios investigated each technology independently and jointly to provide an attributed block model that can feed forward into technoeconomic modelling to determine optimal execution strategies for the mine. This paper presents the first published study combining Grade Engineering and IES to provide mass simulation capability to investigate strategic options for a mining asset.

Nov 10, 2020

By T Baumgartl, D Mulligan, R Haymont

Mining at the Mt Leyshon Gold Mine in semi-arid north Queensland stopped in 2002. Newmont Australia has recently initiated a thorough post-closure water management study of the site by revisiting the existing information and conducting new water-related investigations. The focus of this paper, which is the first publication on post-closure environmental management of the site, is an overview of the site water quality in view of the sources and spatial distribution of polluted mine water, and also the performance of cover systems in controlling water flux though mine wastes. Since the mine closed the rehabilitation of waste rock dumps and tailings dams have significantly improved water quality in the surface receiving waters. However, the Scats Stockpile, the Heap Leach and Old Plant areas, which can potentially produce acidic waters, enriched with heavy metals and arsenic, are the top management priority. Modelling of the potential transport of contaminants in groundwater needs further investigations. A detailed examination of the waters in seepage sumps showed high concentrations of manganese, cobalt, nickel and selenium, which were previously overlooked. The study also showed distinctive chemical signatures for waters at different locations: the waters draining from scats, supergene materials and waste rocks have distinctly lower pH and higher concentrations of dissolved iron, sulfate, heavy metals, Mg, Mn, U, Se and As. While, the tailings sumps are more alkaline, and are enriched in Na and Cl. The southern tailing sump is characteristically As rich. The waters draining from the supergene materials have higher Cu concentrations. Assessment of the cover monitoring systems showed that although covers pass the design criteria, automated recording of data may ignore any failure of the monitoring system. Recalibration of the moisture sensors not only showed realistic moisture values compared to rainfall data but also showed that the permanently installed system records values that are higher than those of the mobile system. Event-driven recording of data overlooks infiltration events. Besides, with a higher time resolution (daily measurements) the breakthroughs could be clearly detected. Modelling of the water balance in covers is underway and an example is given here. Newmont is currently reviewing water management options and is willing to share the lessons learned.

Jan 1, 2006

By G Zhao, S Hapugoda, E R. Ramanaidou, P Hapugoda, Y Jin, G O’Brien

In 2021 the ports of Port Hedland and Dampier in the Pilbara Region of Western Australia handled 900 Mt of iron ore. This ore was produced in the Hamersley’s mines and transported by trains to the ports for subsequent export. Dust, which is generally considered to be particles less than 100 μm in diameter, is generated at all steps in the supply chain. Whilst all dust may have potential impacts on human health and mangroves and buildings a proportion of the dust is classed as respirable (PM10) dust, which consists of particles <10 μm in diameter. In 2021, in response to the community concern with iron ore dust, CSIRO commissioned an internal study to characterise and benchmark the dustiness of the different ores and to develop targeted strategies to minimise dust impacts, without affecting other iron properties, such as stickiness during transportation. A specific concern is that that the dust in the PM10 fraction may contain significant amounts of particulates, such as free silicates which may have health implications for the workers and residents. This study provided detailed mineral and chemical characterisation of the dust generated from the railed fine ore products for five generic Australian ore types: Australian Channel iron Deposit (ACID), Australian Brockman (AB), Australian Marra Mamba (AMM), Australian Pilbara (AP) and Australian magnetite (AM). The dust from these fine ore products were compared to that generated from a sample of Brazilian Hematite (BH) type ore fines. The ores were evaluated for their physical, chemical and mineralogy properties, dust generating potential and understandings of the relationship between the dustiness of iron ores and their physiochemical properties. The size distributions of the railed fine ore products were determined and a suite of analyses were conducted on subsamples of total (-106 μm) and fine (-38 μm) dust. For all the ores, the total dust fraction contains less Fe and more contaminants (SiO2 and Al2O3) than did the bulk ore. The fine dust fraction contained even less Fe and more contaminants (SiO2 and Al2O3) than the total dust fraction. This suggests that the iron ore dust contains more clay and potentially free silica than does the bulk ore. These findings were supported by optical and Scanning electron microscopy analyses of the samples. Dustiness measurements were made for each of the different ores (-106 μm) to investigate the relationship of dustiness of various iron ores with their physiochemical properties and assess their responses to dust suppression by the application of water sprays.

Sep 18, 2023

By P Minkkinen, J Lohilahti, T Korpela, B McPherson

Concentrator plants intake the ore from the mine and produce concentrates by extracting valuable minerals in a succession of process steps. Controlling the extraction process and detecting changes in the process requires updated information on a minute basis. Moreover, due to economical reasons, one must also collect metallurgical samples on a daily basis for monthly reporting.In this paper, we present how slurry samplers were installed in a Cu-Ni flotation plant to accomplish the aforementioned tasks. An on-stream elemental analyser at the plant is used for flotation process control by taking samples from selected process streams. Two process streams, the flotation feed and tail, are also equipped with metallurgical samplers. The metallurgical samplers were designed to have low head loss, be robust and easy to maintain and to collect slurry samples in a reliable way for the metallurgical accounting.Samples were collected by different sampler types and we discuss the uncertainty arising from sampling in the assays. Variographic analysis was carried out on the process data in order to find periodic components in the process, and estimate the correct number of shift sample increments and measurement error components. The metallurgical samplers were proven to be reliable devices with zero downtime and no sanding issues in the main process flows. In addition, we show that the tail measurement is the most important one for the plant recovery calculation, which emphasises the importance of the sampling accuracy in the tail stream.CITATION:Lohilahti, J, Korpela, T, Minkkinen, P and McPherson, B, 2014. Analysis of slurry sampling arrangements at a froth flotation plant, in Proceedings Sampling 2014 , pp 91–98 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 29, 2014

By M Foster

The new environmental legislation of 1986 was left incomplete and to date remains so. The &apos;missing&apos; process by which environmental consideration should be applied was never embodied in law and has predisposition to a wide interpretation. The Resource Statutes which govern land use and development place demands on the environmental process without that definition. The Resource Statutes are themselves under review by Government. There is a new Government Department of Conservation. It is still in its early days and facing a challenge to compose its role as a steward over large tracts of land holding significant marketable resources, animal, vegetable, mineral, and abstract. It has also taken over numerous consent and advocacy roles in legislation beyond its own empowering Act. Enter the mining company, anxious if not able to get an easy passage for consents to prospect and mine, then at least to have a clear path to tread to get there, within a fixed time period. Whichever options appear available to process environmental approvals, public participation is that being favoured most by the regulatory bodies. Where a public notification of consent applications is mandatory, public participation should lead to the fastest track available.

Jan 1, 1988