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The past decade hap seen revolutionary advances in com-munications and information-handling techniques which have been stiriulated by "cold war" military requirements and by, current programmes for probing into outer space: The tools used in exploration for petroleum and minerals have been improved significantly as a result of this new space age technology and even greater improvements are on the way.Two areas of technical activity have been particularly fruitful in enhancing the effectiveness of exploration, methods. These are (1) The development of new approaches, based on information theory, for extracting signal from noise more efficiently than before, and (2) The use of high-speed digital computers for storing and processing all kinds of exploration information, not only geophysical but geological as well.In seismic prospecting, use of information theory has led to new techniques such as time-domain filtering, wave-number filtering and correlation methods which have made it possible to obtain usable reflection data from areas which were previously considered NR. Complex playback and other data processing facilities have been developed to apply these approaches.

Jan 1, 1963

An on-stream iron ore analyser has been developed in collaboration with Hamersley Iron Pty. Limited for determining the iron content of both lump (- 30 + 6 mm particle size) and fines (- 6 mm particle size) on conveyor belts. The analyser, which is called IRONSCAN, is based on pair production, and is now commercially available from Mineral Con- trol Instrumentation Limited (MCI) in Adelaide. It can be mounted under existing conveyor belts with minimal modifications to the conveyor struc- ture, and the presence of steel cables in the belt does not interfere once the analyser has been correctly calibrated. The analyser has been exten- sively tested on both lump and fines on the shiploading conveyor at Damp- ier, and typically the root mean square (r.m.s.) deviation between single IRONSCAN measurements and conventional chemical analyses is better than 0.5% Fe. It is currently being evaluated on - 150 mm ore from the primary crusher at Mount Tom Price, and initial results are encourag- ing. The principal advantage of IRONSCAN is that it provides rapid infor- mation on ore grades. But perhaps its greatest potential is at the primary crusher where conventional sampling and analysis is very expensive to Implement. at the University of Melbourne, and those of us who were his students had learnt of the application of physical chemistry to pyrometallurgical processing, pioneered by Chipman in the USA, Wagner in Germany, and Richardson in the UK. It was possible, by applying this theoretical insight to the equilibria between metal, speiss or Legierung, matte and slag phases, to find a practical and effective way to recover metal values in some residues which had been accumulating for many years at the NA, but which had defied all attempts to treat them to that date. There was also an opportunity to study the batch lead refining methods still in use at all lead refineries apart from Port Pirie, and to devise optimis- ing techniques which greatly improved the operations and effected considerable savings. Next the writer spent some six years alternating between the BHAS, Port Pirie, and Imperial Smelting at Avonmouth in the UK, concerned with lead or lead-zinc smelting, and the develop- ment of several further continuous lead refining processes, before returning to Australia as Section Leader, Process Development in the CSIRO Division of Chemical Engineering, Fisherman's Bend, Victoria. Metallurgical opportunities which arose during this last period included the problem of tin smelting which had developed over about a decade: the world's tin smelters had been accustomed to treating fairly high grade tin concentrates, con- sisting of almost pure cassiterite, with very little impurity-mostly quartz, limestone, iron oxides, and sundry other silicates. Most such concentrates had been produced from alluvial deposits, where nature had already done some of difficult part of the mineral processor's work-at who knows what recovery-so that he could now produce high grade concentrates at high recovery. The smelters were not really set up for the treatment of lower grade concentrates, such as could be made with reasonably high recoveries from rock mining. Thus they imposed such penalties on impurities and lower than desired tin grades, that whenever a mineral processor improved tin recovery at the expense of lower- ing grade, such an improvement entailed a lower financial return to the miner. There was clearly a need for improved understand- ing of tin smelting, (at that time shrouded in secrecy) and develop- ment of techniques better suited to the treatment of lower grade concentrates. As well as the practical development, a start was made with the computer modelling of the smelting process, with the obiect of optimising the process parameters.

Jan 1, 1988

By S Bright, M J. Masamvu, E K. Chiwandika, S Dandi, S M. Masuka

The depletion of high-grade hard and lumpy chrome ores has forced Zimbabwean ferrochrome producers to resort to low-grade friable ores that have an average of 28 per cent fines against a set limit of 12 per cent. Submerged open arc furnaces currently in use are associated with eruptions within the furnace because of the high amounts of fines, high energy consumption, as well as high SO2 and CO2 emissions. Traditionally employed agglomeration methods such as pelletising and the use of coke in the furnace have been discarded because of the pressure to lower operational costs and to achieve higher profit margins. This research aims to develop a method to incorporate lowgrade friable ore fines and unprocessed coal into production while lowering CO2 and SO2 emissions through a closed direct current (DC) arc furnace. The closed DC arc furnace could incorporate the friable ores and coal while maintaining above 90 per cent reduction rates. Preliminary findings also show that energy consumption could be reduced by up to 35 per cent by incorporating a pre-heating and pre-reduction system using the flue gases from the furnace. In the proposed circuit, the cost of production per ton of ferrochrome might be potentially lowered by an average of 30 per cent.

Jun 19, 2024

By D Espinoza, I Rees, J Pocoe, P Collier

P Collier, I Rees, J Pocoe and D Espinoza

Mar 22, 2022

By G J. Sparrow, M J. Fisher-White

A mineral and chemical characterisation study was conducted on ilmenite-rich heavy mineral concentrates sourced from the western sector of the Eucla Basin in southern Australia. Test work involved using X-ray diffraction (XRD), scanning electron microscope (SEM) and electron microprobe-based characterisation methods. Results showed considerable variability in the degree of ilmenite alteration between deposits with TiO2 contents varying from 53 - 63 wt per cent TiO2. Notwithstanding variability between individual deposits, the samples all had [Ti]/[Ti+Fe] ratios >0.5 consistent with a mineral assemblage of hydrated ilmenite or the hydrated, Ti-rich alteration phase pseudorutile (Fe3+2-x Ti3O9-3x (OH)3x). Accessory phases consisted of rutile (primary and secondary), zircon, aluminosilicates, quartz, Fe oxyhydroxides and spinels. Results for the most altered material are broadly comparable with data for ilmenite concentrates from the eastern margin of the basin. The mineralogy of the western Eucla Basin concentrates and the minor element composition of the ilmenite grains suggest they could be upgraded to synthetic rutile by a modified Becher process.

Jan 1, 2008

By J Hudson

Autogenous (AG) and Semi Autogenous (SAG) grinding mills are the conventional selection for large-scale grinding circuits. It is accepted that these forms of comminution are not the most energy efficient available. This efficiency combined with escalating energy prices, steel prices and the requirement to process larger, lower grade deposits has necessitated that better comminution techniques are found to challenge the dominant position of AG/SAG mills in the grinding circuit. Recent advances in high pressure grinding rolls (HPGR), particularly in terms of roll surface protection have meant that, depending on the application, an economic alternative is available to the large diameter AG/SAG mills. Mining companies now recognise the potential benefits of HPGR and so they need proper assessment in the design of new or upgrade of existing grinding processes. Of course, the answer to the question AG/SAG or HPGR is not straightforward and the impact of the grinding process on the whole metallurgical process needs to be evaluated. Clearly this is a complex decision to make and requires substantial metallurgical knowledge, test work, and objective analysis. The perceived downstream processing benefits will differ between different plants depending on the ore type and processing conditions. The optimal design of the comminution circuit requires that a robust methodology is followed to objectively characterise the ore, size the equipment and determine the downstream processing benefits. The paper gives a brief comparison of the capital and operating costs for both grinding systems, and then outlines the appropriate test work that is required to make an informed decision.

Jan 1, 2006

By Zieg GA

The Sheep Creek Project lies 30 km north of White Sulphur Springs in the Little Belt Mountains of central Montana. Homestake Mining Co. discovered base metal anomalous pyrite beds downdip from gossans in 1974. Cominco American began exploration in 1976, consolidated adjacent properties, and joint ventured with BHP-Utah International in 1985. High . grade Cu and Cu/Co mineralization intersected in a 1985 drill hole led to discovery of two separate deposits. The project area now covers over 175 km2 and is being actively explored for Cu, Co and Zn in a shale hosted bedded sulphide system.Proterozoic Belt Supergroup sediments host the Sullivan Pb/Zn deposit, stratabound Ag/Cu ores of the Revett Formation at Troy and Rock Creek, and base metal rich pyrite beds at Sheep Creek.

Jan 1, 1990

By K Vallo, T Haimi, J Pihlasalo, J Hamuyuni, M Lindgren, F Tesfaye

Decarbonisation of the steel industry has recently attracted a lot of research and technological development. Most of the technological developments are centred around the replacement of blast furnace (BF), which has been the main primary smelting furnace in the ironmaking step of steel production. Replacement of the BF is not an easy task because of BF’s many established capabilities over the years, especially its ability to use low-grade iron feed. In this regard, Metso has developed its own technology, Metso’s Outotec direct reduced iron (DRI) smelting furnace, to tackle this problem. The recently developed six-in line electric furnace for DRI smelting can be used for primary smelting of DRI from blast furnace grade iron ore. Unlike the electric arc furnace (EAF), the DRI smelting furnace can handle larger slag volumes that emanate from the high gangue in BF grade DRI. Therefore, fluxing plays an important role in operating the DRI smelting furnace. This paper presents fluxing options and proposes slag quality and operating windows for the DRI smelting furnace. Also, the effect of slag on refractory durability will be discussed.

Jun 19, 2024

By B J. van Loggerenberg

The capital cost of major items of mining equipment is very high. The operating cost of such equipment is also high. It is therefore important that such expensive equipment is used productively. To this end mine management uses production data systems and management accounting systems to monitor events and provide data for analysis to enable management to make operating and business optimisation decisions. This could be done better if there was an understanding of productivity in terms of its utilisation and efficiency components. What has been missing has been a methodology to properly account for the productivity of equipment in terms of its contribution in dollars to the costs and profit of the mine. An explanation of the Productivity Accounting methodology will be given. It will then be shown that productivity has two components, that of capacity utilisation and efficiency. These are defined and the dollar contribution of each to costs and profit shown. The efficiency component tracks the effect of proportional changes in input cost quantities used in the mining process as mining production changes. The capacity utilisation component tracks the effect of step changes in the input cost quantities used in the mining process as mining production changes.

Jan 1, 2003

By Baguley PJ, Napier-Munn TJ

This paper presents preliminary resu]ts from field studies which were conducted to establish, among other things. the influence of medium viscosity on the partitioning behaviour of dense medium cyclones and drums in mineral applications, using frrrosilicon- ba_sed media. The medium vicoosit.y- was measured on-line, and partitioning behaviour was determined using ore sampling and density t r acers . The results demonstrate that viscosity is an important. operating variable, influencing ,eparat.ing density and efficiency under certain conditions. The implication is that metallurgical performance can be optimised by manipulating viscosity, either by appropriate selection of medium' characteristics or by automatic alarming and/or "ontroi using signals from the on- 1. i ne viscometer.

Jan 1, 1987

Chemicals derived from petroleum raw materials satisfy so much of our industrial needs today that it is good to pause and realise two things -ò the petroleum chemical industry is so new, and the use of chemicals is a very old one.Petroleum is such an'abundant and convenient source of raw material that in little more than 30 years it has become the major source of supplyfor chemical rdanuf ctiree This paperw~l'l 'disc'uss t1.e main 'r`easons' for this rapid development by considering the : sub jest -under tkzree headings ea. Source of Raw Materials.b. The Impact of Petroleum Chemicals on Plant Design and Processes. ce Scme of the Major Chemicals Used Today.

Jan 1, 1962

By W Stange, N Hanson

An important aspect of the project evaluation process is the achievement of a clear and quantitative understanding of the primary drivers influencing project value and risk. A business scenario-based approach is required to ensure that the project meets value and risk hurdles over the short, medium and longer term. Adopting an optimising approach can aid significantly in the development of a project concept into a business that is optimal and sustainable in the longer term. Through the application of case studies, based on work performed with various mining organisations during the last five years, this paper will demonstrate how project value and robustness can be optimised. Experience has demonstrated that applying this approach results in significant value improvements and risk reduction û primarily by application of a rigorous, fact-based analysis and optimisation process that rapidly increases management team understanding and insight of key driver of value and risk.

Jan 1, 2007

By Thompson J

A programme of testing and evaluation has been in progress at Isa Mine for the last four years with the objectives of rationalising ground support practices, improving installation quality and increasing productivity of ground support functions.Numerous innovations have been successfully implemented. These include the introduction of swellex rockbolts as the major form of temporary support, the use of splitset rockbolts as the primary means of support for the hangingwalls of cut and fill stopes and the introduction of dowels with pumped cement for general long term support.The installation of swellex bolts has been successfully mechanised throughout the mine using Tamrock automatic rockbolters and Atlas Copco BUK 11R drilling rigs modified for this purpose.

Jan 1, 1985

By A Rantala, J Timperi and J Kaartinen, T Maksimainen, O Haavisto

"X-ray fluorescence (XRF) is the most common technique used for online slurry assaying in base metal flotation applications. Typically, assays from feed, concentrate and tailings slurries are used to monitor and control the flotation circuit, with possible additional sampling locations in other main slurry flows inside the circuit. The elemental content detection from the XRF spectrum is relatively straightforward as the spectrum contains element-specific peaks whose height corresponds to the element concentration in the sample. However, centralised XRF analysers measure the elemental concentrations line-by-line, which may increase the sampling interval for an individual line and cause unnecessary response delays, especially in large flotation plants. Reflectance spectroscopy is an emerging technique that can be used to obtain more frequent measurements from slurries. The measurement is based on the mineral-specific absorbance of light in the visible and near-infrared (VNIR) wavelength range. Due to this relatively inexpensive and simple measurement system, it is possible to conduct the measurement simultaneously in several slurry lines. However, the information contained in the VNIR spectra is more difficult to interpret as concentrations of all the minerals in the sample contribute to the measured spectrum and changes in solids content, particle size and mineralogy disturb the elemental content estimation. Therefore, frequent calibration of the measurement is required. This study presents the application of combined reflectance spectrum and XRF measurements for rapid online slurry assaying in a copper-nickel flotation plant. The XRF assays are utilised as calibration samples for the reflectance spectrum measurement, keeping the calibration model up-to-date. The rapid reflectance spectrum analysis is then used to provide an almost continuous estimate of the slurry contents, enabling further improved process monitoring and control.Citation:Haavisto, O, Maksimainen, T, Rantala, A, Timperi, J and Kaartinen, J, 2016. Reflectance Spectroscopy with X-ray Fluorescence for Rapid Online Assaying in a Copper-nickel Flotation Plant, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 85–92 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By M Campbell, A Jeffcoate, J-C Vannay, B Perriaux

Phyllite waste rock at the Simandou Pic de Fon and Oueleba Iron Ore deposits (Guinea, West Africa) variably weather to form clay-rich rocks. This weathering modifies the mineralogical, geochemical and mechanical properties of the phyllites. Final pit walls will largely be formed in phyllite, so it is critical that the slope design takes account of the distribution and variability of weathering within this material. Phyllite intact material strength has been correlated with geochemistry (ie mineralogy) facilitating the establishment of domains of intact rock strength (IRS). In order to calibrate this geochemically-based strength model, core from diamond drilling (DD), comprising a variety of phyllite material types (from soft clay to moderate strength rock), was geotechnically logged to assess intact strength; further validation was achieved by uniaxial compression (UCS) testing and point load tests (PLT). The correlation between geochemistry and strength offers a potentially powerful tool for differentiating basic mechanical properties of the rock mass, especially at Simandou where a significant proportion of the resource drilling is done by reverse circulation (RC). Unlike DD, reliable measurements of material strength from RC samples can prove difficult, especially in clay-rich material. Therefore, gaining information from routine geochemical assay results, independent of the sampleÆs physical integrity, is a valuable and cost-effective source of reliable empirical data. Data acquired using this approach provides an opportunity to develop strength domains, which are integrated into mine planning block models. In combination with other geotechnical characteristics, this can be a valuable input to the development of geotechnical models. This technique has allowed spatially representative rock strength data to be derived and offers the potential for optimising pit slope angles in areas where hitherto conservative design criteria had been assumed.CITATION:Jeffcoate, A, Campbell, M, Vannay, J-C and Perriaux, B, 2013. Modelling intact rock strength of clay-rich rocks with geochemistry at the Simandou iron ore deposit, Guinea, West Africa, in Proceedings Iron Ore 2013 , pp 193-202 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

The general principles of technical due diligence best practice that are involved in assessing a mineral property in the early stages of its development are described and a bibliography of relevant papers is attached. The issues specific to the evaluation of gold deposits are highlighted. The Australasian Institute of Mining and Metallurgy's (The AusIMM) initiatives in this area, dealing with the proper public reporting of Reserve/Resource information (JORC Code) and property assessment/valuation (VALMIN Code), will be used as a framework against which the illegal tampering with drilling samples to artificially boost their gold content (salting) from the Busang gold deposit (Kalimantan, Indonesia), owned by Bre-X Minerals Limited (Calgary, Canada), will be reviewed. While the Busang saga was based upon fraud, through salting the samples, the general lessons to learn from such a scam are worth documenting. In Australia, most of those working in the mineral industry belong to long established professional institutes and consultant associations (eg The AusIMM or Mineral Industry Consultants Association [MICA]) that require their members to work within their technical limits and to comply with best practice guidelines, or risk being judged and found wanting by their peers in the context of strong Ethics Codes. There is also a strong interface between such representative professional bodies and the corporate and financial market regulators (ASC/ASX), which closes the monitoring loop. Canada has only now seen the wisdom of having this type of early warning system in place. Fraud and deliberate deception will be always possible, but deception on the enormous scale that occurred at Busang is most unlikely with proper surveillance systems in place and the use of accredited technical professionals. There should have been more hard data available about so big and rich a deposit owned by a C$6Bn company.

Jan 1, 1997

By A Jewbali, R Perry, R Inglis, L Allen

"The use of conditional simulation to characterise mine plan uncertainty is increasing for the assessment of risk in mining projects. While the development of grade uncertainty profiles is relatively straightforward and can be validated using standard geostatistical techniques, the addition of geological uncertainty to evaluate total risk remains problematic. Some of the problems associated with geological uncertainty methods include the clustering of data in favourable geologic units, difficulty in training image definition and the inability to address change of support issues for categorical variables. Despite these obstacles, the importance of geological uncertainty as a contributor to total uncertainty has prompted Newmont to explore and evaluate the use of various techniques (and combinations of techniques) on different deposit types.Two orogenic deposits of different geological complexity were selected for the study: Subika, a shear zone-hosted deposit, and Merian, a deposit containing gold mineralisation associated with quartz vein zones and stockwork within which are found higher-grade quartz breccia zones. Newmont trialled various categorical simulation approaches to determine the applicability of these methods for each deposit type and the effect of parameter choice on the width of the uncertainty interval. Some of the techniques that were trialled include multiple point statistics methods, sequential indicator simulation using local probabilities as well as variations of these methodologies.The goals of this study included: gaining an understanding of which techniques may work best in which deposit types gaining an understanding of the intricacies of each method gaining an understanding of the effect that each method has on total uncertainty analysis.This paper presents a comparison of the various techniques and makes recommendations for their use in uncertainty analysis.CITATION:Jewbali, A, Perry, R, Allen, L and Inglis, R, 2014. Applicability of categorical simulation methods for assessment of mine plan risk, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014, pp 85–98 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 24, 2014

By R Atmuri, W Liang, R Prasad, Y Liu, E Wingate

Yellow phosphorus (YP) has been commercially produced since the 1920s. First in the USA by the Tennessee Valley Authority (TVA), next in Russian (Kazakhstan) in the 1950s, and finally in China in the late 1970s and early 1980s. There are operations in Vietnam and Sarawak on a smaller scale. YP has become very in vogue due to its use in the production of lithium iron phosphate battery cathode precursor materials by the Chinese and other western battery manufacturers. The YP is also used to produce purified phosphoric acid and higher grades of acid using a thermal oxidation process after smelting. This paper will look at the basics of the smelting including slag chemistry, alloy chemistry and offgas chemistry. The paper will look at the design of the furnaces used in the YP production process as well as the downstream recovery of phosphorus from the smelter off-gas stream to YP. The next part of the discussion will focus on the operations of a YP smelter with regards to control of the furnace to optimise phosphorus recovery to YP. Will discuss tapping cycles for alloy and slag with a view to optimal phosphorus recovery. The discussion will close out with a review of operational challenges in the smelter and a brief description of the downstream conversion of YP to high purity phosphoric acid.

Aug 21, 2024

By Davies S. G, Jayaweera A

The oxidation of nickel sulphide and copper sulphide concentrates, and coal, has been studied under non-ignition and ignition conditions using Differential Thermal Analysis (DTA) and Thermogravimetry (TG). The non-ignition reaction was favoured by slow heating rates < 10°C min-1), low masses < 10 mg) and an air atmosphere. Under these conditions, the typical stepwise oxidations of the various sulphide minerals present in the concentrate were observed as resolved exothermic peaks in the DTA curves and weight losses in the TG curves. Above a heating rate of 10°C min-1 , sample masses in excess of 10 mg and an oxygen atmosphere, an ignition reaction was induced, as indicated by a major high energy exotherm in the DTA curve and a major rapid weight loss in the TG curve. The ignition temperatures of the minerals under ignition conditions, found for 15 mg samples heated at 20°C min-1, were 434°C for the nickel sulphide concentrate, 372°C for the copper sulphide concentrate, and 230°C for the coal. By plotting a curve for mass against ignition temperature at constant heating rate and extrapolationto zero mass, a value of 470°C was obtained for the mass independent ignition temperature of the nickel sulphide concentrate. Ignition temperatures and extents of reaction at various temperatures were obtained using the TG technique in a novel manner which produced heating rates of 4500°C min-1. Under ignition conditions, the oxidations approximate to flash smelting conditions.

Jan 1, 1985

By A Karrech, C Schrank, O Gaede, I Canbulat

Strain-based failure criteria have several advantages over stress-based failure criteria: they can account for elastic and inelastic strains; they utilise direct, observable effects instead of inferred effects (strain gauges versus stress estimates) and they model complete stress-strain curves, including prepeak, non-linear elasticity and post-peak strain weakening. In this study, a strain-based failure criterion derived from thermodynamic first principles utilising the concepts of continuum damage mechanics is presented. Furthermore, implementation of this failure criterion into a finite element simulation is demonstrated and applied to the stability of underground mining coal pillars.In numerical studies, pillar strength is usually expressed in terms of critical stresses or stress-based failure criteria where scaling with pillar width and height is common. Previous publications have employed the finite element method for pillar stability analysis using stress-based failure criterion, such as Mohr-Coulomb and Hoek-Brown, or stress-based scalar damage models.A novel constitutive material model, which takes into consideration anisotropy as well as elastic strain and damage as state variables, has been developed and is presented in this paper. The damage threshold and its evolution are strain-controlled, and coupling of the state variables is achieved through the damage-induced degradation of the elasticity tensor. This material model is implemented into the finite element software Abaqus and can be applied to 3D problems.Initial results show that this new material model is capable of describing the non-linear behaviour of geomaterials commonly observed before peak strength is reached as well as post-peak strain softening. Furthermore, it is demonstrated that the model can account for directional dependency of failure behaviour (ie anisotropy) and has the potential to be expanded to environmental controls such as temperature or moisture.CITATION:Gaede, O, Schrank, C, Canbulat, I and Karrech, A, 2014. A strain-based failure criterion for pillar stability analysis, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 393–398 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014