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By C M. MacRae

The characterisation of high-P iron ores by field emission gun electron probe microanalyser (FEGEPMA) was carried out to determine elemental associations in iron oxides sensus lato and, using this knowledge, to speculate on possible P incorporation mechanisms in goethite. Quantitative data was collected from two goethite-rich bulk ores and results showed that in both samples goethite was the main repository for phosphorus. The P-rich goethite also contained elevated levels of both aluminium and silicon.To understand the mechanism of P incorporation in goethite, high-P grains were located by coarse mapping of polished blocks with the FEG-EPMA. Analysis of element distribution maps collected on the P-rich grains showed that low-P regions within grains were typically associated with low-Al and high-Si, whereas high-P regions were associated with high-Al and low-Si. Based on follow-up quantitative analyses, a coupled substitution mechanism for phosphorus incorporation within goethite was proposed: 2Si4+ = 1P5+ + 1Al3+. Additional quantitative analyses on further examples indicated the mechanism was only valid for Si contents in goethite of <1 wt per cent.Preliminary transmission electron microscope (TEM) studies confirmed the presence of P, Al and Si in goethite.

Jul 11, 2011

By R L. Brathwaite, R Carver

The REGCHEM (Regional Exploration Geochemistry) database of open file mining company data, managed by GNS Science, has recently been upgraded with the compilation of additional data, especially for the Otago region (see http://maps.gns.cri.nz/website/minmap). In June 2007, data compiled for the Otago region included more than 2000 stream sediment samples from 19 surveys, more than 800 BLEG (bulk leach extractible gold) samples from 12 surveys and a few pan concentrate samples. The stream sediment samples were typically analysed for Au and As, and in many cases for other elements including Cu, Pb, Zn, Sb, W and Mo. The BLEG samples were analysed for Au and in some cases also for As. The main exploration target was mesothermal gold deposits in the Otago Schist, although one survey of the Otago Peninsula targeted potential gold deposits associated with the Dunedin volcanic complex. Geochemically, the mesothermal gold deposits are characterised by anomalous As and Au, with some also characterised by anomalous W and Sb, and these four elements are the best pathfinders in stream sediment geochemical surveys. The introduction of lower detection limits in Au analyses in the more recent stream sediment surveys and in the BLEG surveys enables the use of this element as the primary pathfinder for mesothermal gold deposits.

Jan 1, 2007

By Iley J. D, Siviour N. g, Moffatt R. J

The process of desilverising by fractional crystallisation with reflux was investigated through laboratory batch tests and continuous laboratory bench scale tests at CSIRO Clayton, to a 300 kg/hr pilot plant at Port Pine. The pilot plant built at BHAS comprised a vertical cylindrical refining column with internal diameter 250 mm and height 3.2 m, attached at the top to an off-set cylindrical stirred crystalliser tank. Crystals were made in the crystalliser by intermittent immersion of steel cold fingers, which were water cooled between immersions. Gas heat was used for melting the crystals at the base of the column and for side compensation heating. A computerised in strumentation system was employed for data logging and for controlling some critical plant operations. A mechanical device was first employed to promote counter-current plug flow of crystals down the column against the rising stream of reflux liquid, but this was found to be unsatisfactory owing to excess noise, frequent mechanical failure, and excessive accumulation of dross. Plug flow was finally promoted by pulsing the column. Low silver levels, less than 1 gitonne, were achieved with both methods of crystal transport under total reflux conditions. The pulsed column gave results for silver and bismuth which agreed with the theoretical predictions of a computer model, but there was some selective drossing of antimony. In the mechanically agitated column, excessive drossing promoted selective removal of most of the antimony and some of the bismuth, and the results after extended operation were well removed from the theoretical predictions. Plant failures and operating problems prevented the achievement of satisfactory product quality with the necessary reliability under production conditions. Other priorities necessitated the termination of the project before the process could be optimised.

Jan 1, 1989

IN all wet concentration processes it is of primary importance to determine to what degree the crushing must be carried in order to obtain the maximum profit per ton of ore milled.To effect a clean separation, either by gravity or flotation treatment, between either one valuable sulphide from another, or a sUlphide from the gangue, the ore must have been subjected to grinding to such an extent that the particles to be separated are completely liberated from each other.Insufficient crushing will result in either an incomplete separation of the sulphides from each other, and thus a loss of the one sulphide in the other, or else a loss of the valuable sulphide in the gangue.This being so, the question arises whether the added cost of extra crushing would be economically warranted by the increased recovery consequent on such a step.

Jan 1, 1927

By M D. Goodz

MacPhersons Reward gold deposit is in a post-kinematic tonalite intrusion which is a setting different from many other deposits of the Coolgardie goldfield that are hosted in early Archaean tholeiitic sills or meta-sedimentary rocks. Gold mineralisation at MacPhersons Reward consists of auriferous quartz veins that are best developed in the tonalite but extend to the adjacent komatiitic rocks and along the lithological contact zones. The gold-related alteration halo is dominated by biotite-chlorite and pyrrhotite. Unlike many other Coolgardie deposits, the As concentrations are low.

Aug 22, 2011

By Carthew SJ

The early period of South Australia's mining history was dominated by Cornishmen as large numbers of miners and their families migrated to escape closure of the Cornish copper mines. Records show that Carthew families migrated from Kent and Cornwall to South Australia. Those from Redruth, Cornwall, were miners and their family history provides an insight into the condi- tions under which early miners lived and worked. Carthews are one of the oldest surviving mining families in South Australia and their movement pattern has been typical of many other early Cor- nish mining families.

Jan 1, 1987

By J Watt

The Hidden Valley Gold Project is located in a remote and mountainous area of the Morobe Province approximately 30 km south of the township of Bulolo and approximately 90 km south-southwest of the provincial capital, Lae. The Hidden Valley deposit was discovered in 1984 with the nearby Hamata and Kaveroi deposits discovered in 1987 and 1992 respectively. Reserves (Harmony, 2009) at these three deposits are 42.1 million tonnes of ore containing approximately 2.9 million ounces of gold and 45 million ounces of silver. A further 5.4 million ounces of gold and 84 million ounces of silver are in the resources category. The process plant is designed to treat 4.2 million tonnes per year of gold/silver ore extracted by open cut mining methods. Ore is classified into three ore types according to oxidation state: oxide, transition and primary. The silver to gold grade ratio is high for the Hidden Valley and Kaveroi ores, generally in the range 15 - 20:1, and much lower for Hamata, typically 1 - 2:1: Primary ore is the dominant ore type at Hidden Valley with sulfur grades up to about two per cent sulfur. Oxide and transition ores are more prevalent at the Hamata deposit, but its primary ore has up to five per cent sulfur grades. Variable ore types, particularly in the initial years of operation, high silver to gold ratios and limited plant site area, due to the challenging terrain, present the main processing challenges for this project. This paper describes the operating strategies and process development for the main areas of this circuit, highlighting selections of processes and equipment that achieve cost effective, yet flexible solutions to the treatment of ores from these deposits.

Jan 1, 2009

By H Zhou, T Honeyands, M Zhou

In iron ore sintering, packing the granules onto the sintering strand to form a porous bed with optimum permeability is a complex dynamic process. The packed bed voidage is the key factor determining the flame front speed and the final sinter productivity and quality. Previous studies have found that granules are soft quasi-particles with a typical structure of nuclei with an adhering fines layer. The deformation of the adhering layer greatly affects the bed voidage during packing, which is related to the strength of the adhering layer and the force exerted on the granules. In this study, tablets simulating the particle size distribution in the adhering layer of granules were made for four single ore blends. Both the tensile strength and shear strength properties of these tablets were investigated as a function of water content by the uniaxial compression test and direct shear test respectively. The results of compression tests show that the adhering layer becomes weaker and more compliant with the increase of moisture. The most porous ore has a more rigid adhering layer than the other three tested iron ores at any given moisture content. In direct shear tests, the internal friction angle of the adhering layer ranged from 31° to 37° and varied little with the moisture content or ore type. The cohesion constant is around 1 kPa and is quite small compared to the stress applied to the granules during packing. Combined with the results of granulation and packing experiments, the influence of the adhering fines layer deformation on the degree of voidage loss is specifically discussed.CITATION:Zhou, M, Zhou, H and Honeyands, T, 2017. Tensile strength and shear strength properties of the adhering layer of granules in iron ore sintering, in Proceedings Iron Ore 2017, pp 117–112 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By R Dimitrakopoulos, C Paduraru

The optimisation of mine complexes and related value chains is a challenging problem due to the simultaneous presence of a highly-dimensional decision space, integer decision variables, non-linear constraints and recovery functions, as well as geological and market uncertainty. In addition, if the uncertainty is revealed progressively, then decisions need to continuously adapt to new information, which poses additional challenges. Stochastic dynamic programming is a well-known class of methods for addressing problems where a decision-maker reacts to new information. While simplistic applications of dynamic programming using exact representations would be intractable for any realistic mine planning problem, new dynamic programming methods using approximate value function representations have been successfully implemented in the past to address problems of similar complexity. This work formulates the problem of mine complex optimisation as an approximate dynamic program and presents an application of the resulting method to a gold-copper deposit.CITATION:Paduraru, C and Dimitrakopoulos, R, 2014. Mineral supply chain optimisation under uncertainty using approximate dynamic programming, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014 , pp 415–422 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

The Martha deposit is an economic giant epithermal gold deposit, with mined and unmined resources of more than 218 000 kg (7 Moz) Au. The Au-Ag, base metal sulphide-bearing quartz lodes in the Martha deposit form an extensive braided pattern within hydrothermally altered andesite wall rock. There are five main quartz lodes: 1.      Martha, 2.      Welcome, 3.      Edward, 4.      Empire, and 5.      Royal.   Information from historic mine plans and reports has been used to determine the depth distribution of economic ore within the Martha deposit. Economic ore (average of 10 g/t Au) in the Martha underground mine was at a maximum width and strike length between a vertical depth of 160 and 350 m. Below this depth the quartz-sulphide lodes continue, but the grade declined to sub-economic grades (< 4g/t Au) at about 575 m depth and economic ore shoots were localised, mainly on the hangingwall side of the lodes. Samples from exploration drill holes indicate that this decrease is associated with a depth zonation from electrum-bearing Zn-Pb-Cu-Ag sulphide ore (average 10 g/t Au) to sub-economic (< 2 g/t Au) electrum-poor Zn-Pb sulphide mineralisation.

Jan 1, 2006

During recent years there has been a marked increase in the use of explosives in Queensland coal mines. Delay detonators have been introduced and their use has extended with the wider application of mechanised methods of mining.The need for careful study of the characteristics of delay detonators is stressed so that the advantages of simultaneous firing, from the points of view of safety and efficiency, may be obtained. With their use new potential hazards are introduced. These hazardsare considered and means whereby the overall safety may be improved are discussed.The increase in the number of misfires since the introduction of delay detonators is shown and the examination of misfired detonators is described. Lessons to be learned! from these misfires are noted and details are given of the essential requirements for safe and efficient blasting using delay detonators.INTRonUCTIONOne of the aims of mechanization in coal mines is to reduce the physical effort applied to the winning of coal. Explosives play an important part in achieving this and, following the introduction of power borers for the drilling of shot-holes in Queensland coal mines, much of the arduous work associated with coal getting has been eased. During recent years there has been a marked increase in the consumption of explosives, as shown in Table 1, and it must be the aim of all to use these explosives safely and efficiently. That there are dangers associated with the use Of explosives cannot be denied. The shotfiring operation is fully covered by legislation and, being under the control of one man, shQuld be capable of being carried out with a high degree of safety. The main source of accident appears to be the failure to take proper cover and this has resulted in...

Jan 1, 1958

By M Saghaeian, A H. Baladastian, A Dehghani Ahmadabadi, V Sheikhzadeh, R Hejazi

This research was done to reduce silica from mixed hematite concentrate of Barfkar Iron Ore Sample and increase Fe grade using reverse flotation method (Depressing Hematite and floating Silica). The used sample in the reverse flotation tests was a mixture containing two types of hematite concentrates (Spiral cleaner concentrate and Slon-VPHGMS cleaner concentrate) with the percentage of 16 per cent and 84 per cent, respectively. Fe grade of two samples was 59.31 per cent and 57.52 per cent and SiO2 grade was 5.83 per cent and 6.71 per cent, respectively. After mixing, the Fe and SiO2 grade of the mixed sample was measured at 58.10 per cent and 6.20 per cent. For flotation tests, effect of variable operational parameters including feed size distribution (d80 = 130 microns and d80 = 53 microns), pulp solidity (25 per cent and 30 per cent w/w), pH (9.70, 10.20 and 11), Sodium silicate as a dispersant (500, 1000 and 2000 g/ton), Starch as a depressant (500, 1000, 2000 and 3000 g/ton) and EDA as a collector (180, 300, 400 and 500 g/ton) were investigated. For evaluating the influence of Sodium silicate and Starch dosage, initial flotation tests were performed on the main sample (d80 = 130 microns). These two parameters had no significant effects on the yield, Fe, and SiO2 grade of flotation concentrate based on test results. In the next step, screen analysis was carried out on the main sample for mineralogical studies. Accordingly, the suitable size distribution for releasing Fe and SiO2 particles was smaller than 53 microns. Therefore, the sample was crushed until d80 = 53 microns. Then, supplementary tests were performed on the crushed sample for studying the pH range, pulp solidity, and EDA collector dosage. After doing silica removal flotation tests based on the designed pattern and comparison of the results, the conditions consisting of size distribution d80 = 53 microns, pulp solidity 25 per cent, pH 10.20, Sodium silicate 1000 g/ton, Starch 1000 g/ton, and EDA 500 g/ton was selected as optimum values. In the last test, Fe and SiO2 grade was measured at 60.00 per cent and 3.93 per cent, respectively, and Fe recovery was obtained at 74.93 per cent.

Aug 24, 2022

By N Power, R Hassell, E Jones

Wiluna Mining Corporation are progressively re-entering the old Wiluna underground mining complex. The existing underground was abandoned in 2013 by previous owners and left to flood with water levels reaching above the East Pit portal and Happy Jack Pit portal and up to 300 m below surface in the Bulletin underground. Re-entering the mine commenced in 2017 with dewatering of the Bulletin decline. The underground development had been previously supported with friction bolts, with weld mesh in places. Until mid-2021 rehabilitation requirements were based on an external visual inspection of the installed ground support scheme. However, several incidents involving falls of ground due to corroded bolts have occurred during this time, showing that this approach was inadequate. The challenge the operation faced was should the entire decline be rehabilitated, the implication being not only a large rehabilitation cost but also the impact of severe delays to the mining schedule. The question was asked can the operation better understand the level of corrosion damage and potentially optimise rehabilitation requirements. A proposal to use a systematic approach to assess corrosion by environmental condition mapping, visual external corrosion assessment, and internal corrosion assessment via borehole camera inspections was provided and accepted by Wiluna Mining Corporation. The objective of this work was to produce a three-dimensional map showing the degree of corrosion on the reinforcement systems in the capital infrastructure, this would then be used to risk assess and prioritise rehabilitation requirements. This paper summarises the approach, methodology and results that provided the Wiluna mine planning team with information to enable planning of resources and budget to justify priorities of rehabilitation.

Nov 29, 2022

The mining industry provides employment opportunities for individuals from a wide variety of disciplines. Solid Energy New Zealand Limited (Solid Energy) is New ZealandÆs largest coal mining company and the career opportunities for school leaver trainees and university graduates are numerous. Solid Energy also provides fixed term opportunities for consultants and contracting companies, who complement the wealth of knowledge already within the company.   Focussing on Stockton Mine and my involvement there as an Engineering Geologist, this paper looks at Stockton Mine and the Stockton Water Management Project and outlines the career paths of other young professionals also working at Stockton.

Jan 1, 2007

By G Solly, P J. Leevers

Day-to-day operating practices at existing operations need provide high quality data for decisions that will impact directly on the potential value of the available resource, in addition to meeting standards of quality expected of data used in feasibility studies that will be completed to obtain additional capital required to finance operational improvements. Drill hole location, down hole survey and assay data standards of accuracy and precision have received considerable attention in recent years. The authors propose that geological descriptions of both cored and non-cored drilling warrant at least equal attention, considering their fundamental role in establishing the framework used for geological modeling and resource estimation. The iron ore deposits of the Middleback Ranges have been a major source of iron ore for almost a century. High-grade hematite-dominant ore is currently mined by OneSteel from three open pit operations supplying ore to the companyÆs integrated steelworks at Whyalla. A review of OneSteelÆs future iron ore resources, commenced in 2002, highlighted the need for more flexible and comprehensive management of all forms of geological data used in resource evaluation. Driving this program was the information needs of feasibility studies of the Iron Magnet deposit, located beneath the existing Iron Duke and Iron Duchess mines. Prior to the beginning of 2003, resource evaluation drilling data collected by OneSteel was managed using an in-house system based on industry standard relational database software. The system was demonstrably effective in ensuring the fundamental integrity of basic drilling data, but lacked necessary capabilities for the acquisition and management of geological descriptions, geotechnical and geophysical data obtained by down-hole logging. OneSteelÆs existing system for the management and interpretation of geological descriptions was restricted to storage of a single three digit code for each lithological description interval. The original logs for a large number of older drill holes could not be located, having been either poorly archived or culled from the database in the belief that they did not contribute to the understanding of the resources currently being mined. The three digit codes represented a combination of lithological and stratigraphic descriptions, including many subtle variations in iron ore colour and texture believed to be associated with variations in geochemistry, but subsequently demonstrated to be either incorrect or inconsistently applied. This resulted in the establishment of a plethora of codes for a relatively small number of distinct lithologies. Improvements implemented by OneSteel geologists addressed these shortcomings by ensuring the new data management system: facilitated the objective description of lithological characteristics; distinguished between obsevations and interpretations (eg lithology versus stratigraphy); promoted consistency between descriptions provided by different geologists; and helped to ensure data integrity by developing an audit trail for alterations made to data subsequent to its acquisition. The data used to develop interpretations of mineralisation distribution and characteristics are fundamental to the effective utilisation of a mineral resource: any mineÆs most important asset. Resource related risk is widely recognised as the principal source of technical risks affecting resource development projects, whether they are new mines or expansions of existing operations. A key lesson from this work is that most commercial or æin-houseÆ developed geological data management systems are able to handle basic data validation tasks effectively. Geologists, however, need to ensure that the data management system is appropriately structured to help promote the acquisition of objective and consistent data for interpretation.

Jan 1, 2003

By T Kojovic

"The index A*b, determined from the Julius Kruttschnitt Mineral Research Centre (JKMRC) drop weight tester (DWT) results, has become well-known in the mining industry as a reliable measure of ore hardness in impact or crushing, having the inferred units of t/kWh. This index evolved from a long history of comminution studies at the JKMRC, including the development of the now superseded JKTech twin-pendulum, the industry standard JK Drop Weight Tester (JKDWT) and the faster alterative JKMRC rotary breakage tester (JKRBT). A reduced version of the DWT, the semi-autogenous grinding mill comminution test (SMC test®), also provides estimates of the A*b though the testing of only one particle size at five specific energies. Experimental determination of A*b using the above devices/tests requires samples, with sufficient mass, to be sent to designated laboratories, registered to conduct such tests. This protocol is fine for bankable and commercial testing, where material characterisation data is used in conjunction with machine specific data in modelling and simulation, and power based calculations. However, for comparative testing, where results are required at the time of sampling (eg for plant troubleshooting or spot-surveys), or for rapid ranking of geometallurgical samples, these existing tests simply do not provide a timely, viable and cost-effective solution. In order to address this critical void in the realm of comparative testing, a new device has been developed, exploiting a central feature of single particle impact testing – that the A*b can be reliably estimated using one precise low energy test. This device, for which a patent is currently pending, called the HIT (Hardness Index Tester), has been precision engineered to allow users to break narrowly sized fragments at a set specific energy, in a safe and easy manner. The manufacturing materials have been chosen carefully to ensure compatibility with the intended use and portability to any site, whilst minimising cost. The device is supplied with a novel quality assurance / quality control (QA/QC) feature, to ensure that the targeted potential energy is consistently delivered. The product from the HIT breakage test can be quickly sized using a single screen to determine the mass per cent undersize, from which the A*b index is calculated directly at site – eliminating the need to send the raw data off-site for analysis. On presized fragments, a single test using 20 fragments takes less than five minutes to complete, and the results are immediately available. The HIT is currently being tested at a major mining laboratory in the US and the results to date have proved it can deliver on all fronts. This paper describes the new prototype device, which offers users a low cost in-house mechanism for estimating the A*b at any mine site, with potential applications on fragments up to 25 mm from drill core, blast chip rejects or the grinding circuit feed. It also outlines the results of field tests carried out by an objective third party mining group and compares the results with those from current industry standard tests conducted on the same material.Citation:Kojovic, T, 2016. HIT - a Portable Field Device for Rapid Testing at Site, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 9–16 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

Mining projects have long since presented challenges for the protection of the water environment. Lessons learnt from historical pollution incidents and increasingly stringent environmental controls have significantly improved the environmental performance of mines in developed countries. In contrast, water protection legislation and guidance in the Former Soviet Union (FSU) countries, based on the æpolluter paysÆ principle, has not promoted the prevention of water pollution, and examples of poor environmental performance in mining still exist. However, there is now evidence of emerging legislation encouraging the protection of the water environment. This paper provides an overview of water protection legislation in the Russian Federation and Armenia and highlights some of the challenges facing international mining companies developing projects. A mining case study is described, which highlights how communities in Armenia increasingly value their water environment. Here, greater public participation in development projects is playing a vital role in influencing water protection legislation. It is considered that public opinion and emerging legislation will increasingly present challenges for the development of mining projects.

Jan 1, 2006

By G J. Zhang

The shape and particle size distribution of caved ore mass in sublevel caving were investigated in this study. The paper first reviews the main factors affecting the shape and characteristic of caved ore mass in sublevel caving and then through the experimental blast testing with cement-sand concrete models, the shape and particle size distribution of caved ore mass were found out. The experimental results indicated that the shape and particle size distribution of caved ore mass was similar to that of the drawn loose body. This finding presented a new perspective for the future study on the ore drawing theory and on the optimisation of structural parameters of sublevel caving. The structural parameters must meet the principle that the shape of the drawn body is in consistency to the shape of caved ore mass.

Jul 11, 2011

By P J. Terbrugge

Many ore deposits have considerable vertical extent which is not always known at the time of commencement of mining. In many of these cases, initial mining is by opencast methods, and as ore reserves are proved to greater depths, the pits are often planned to go deeper than had been originally envisaged. In such cases, surface plants and critical underground facilities such as conveyer tunnels, access ramps, ore passes, hoisting shafts and ventilation shafts are often located much closer to the pit rim and the orebody than is desirable for the deeper mining situation. This usually raises the question of the stability of such underground excavations, which may be critical for the viable longer-term mass underground operation of the mine. In this paper the key considerations in the evaluation of the stability of the overall mining environment for ædeepened minesÆ are defined. Aspects which are dealt with are: open pit stability, shaft stability, dilution, mudrushes and airblasts, and selection of mining method. The necessary stability evaluations are put into the appropriate context by considering two case histories. Critical parameters and considerations which need to be addressed during the evaluation of excavation interaction are also discussed.

Jan 1, 2000

BlIP Minerals is a large, diversified, international mineral producer. This paper describes the company's operating strategy, and identifies the role of mineral processing in this strategy through three examples: the column flotation installation at Escondida in Chile, the leach-SX-electrowinning plant, proposed for Escondida, and the whole-ore roasting process being constructed for the Syama gold operation in Mali. It is concluded that the application of appropriate and sometimes novel mineral processing technologies can achieve significant benefits in reduced operating cost, improved product quality, and in some cases the exploitation of previously uneconomic deposits, thereby providing strategic advantages to the company.

Jan 1, 1993