Search Documents

By P Khalkho, M Singh

Rock masses when subjected to uniaxial or triaxial cyclic loading (eg in hydraulic running tunnels, during retrieval and injection of oil and gas from storage underground caverns and haulage roads), the material has a tendency to fail in fatigue. In order to design safe and reliable underground structures, the determination of brittleness under such loading conditions becomes a pre-requisite. Brittleness influences strongly the failure process and makes the rock mass behaviour complex under different tunnelling and mining activities. Brittleness Index is a term to quantify the brittleness feature of a specimen. In the present study, an attempt has been made to quantify the brittleness of jointed specimens using different brittleness criteria. The joints of the model jointed specimens were oriented at an angle of θ=15° normal to the loading direction, each having three different JRC’s=2–4, 12–14 and 14–16. The specimens were tested under triaxial conditions in incremental complete cyclic test scheme performed at displacement-controlled mode. Different brittleness criteria were used ie stress-strain dependent brittleness index, Young Modulus approach and energy-balance based mechanism. It was observed that energy-balance based mechanism which consider the post failure behaviour is more descriptive to reflect the whole variation of brittleness from sheer brittleness to ductility.

Nov 29, 2022

By Aziz NI, Bridgwood EW, Singh RN

One of the major impacts of using modern mechanised systems of mining is the production of large amounts of extraneous dirt intermixed with the Run of Mine output. The paper out- lines a proposed system of utilizing liquid tailings from coal mines to replace imported cementitious materials used in ground control and various other safety measures. A geotech- nical and cost assessment of the proposed system are also included. The paper concludes that it is possible to utilize processed tailings to cost effectively replace imported packing material for ground control.

Jan 1, 1986

By M I. Pownceby, S Hapugoda, H Han, V Nunna, L Lu

Charcoal produced from Syzygium Zeylanicum (local name: Yakada Maran = iron killer) trees were widely used in ancient Sri Lankan iron smelting practices. In this study, relict charcoal from Syzygium Zeylanicum tree trunks, branches and leaves were analysed for the first time. Unusually high concentrations of calcium oxalate (CaC2O4.H2O – CaOX) crystals were identified preserved in plant cell structures by optical mineralogy and SEM analysis. Thermogravimetric Analysis (TGA) of CaOX showed that it displayed three decomposition stages, releasing H2O at 177°C, CO at 493°C and CO2 at 750°C. Following the identification of CaOX in Sri Lankan charcoal, a series of reduction tests on a low-grade, high-P iron ore fine sample (high SiO2: 5 wt. per cent; Al2O3 4 wt. per cent; P: 0.135 wt. per cent) doped with CaOX were carried out at various temperatures. Samples were analysed by XRF, SEM and EPMA to determine the degree of reduction and the effect of reduction on the deportment of impurities, in particular P. Reduction tests at 800°C and 900°C with 5 wt. per cent CaOX showed that the reducibility increased to over 65 per cent. At temperatures above 900°C, P was located mainly within a fine, interstitial glass matrix suggesting that the CaOX flux enhanced removal of P from iron-rich pre-cursor phases to form glass. Preliminary magnetic separation tests to remove the P-rich interstitial glass were unsuccessful due to the fine grain size. Further complete reduction tests at temperatures above 1200°C with addition of coke to convert the iron oxides into Fem were conducted with samples doped with 10 wt. per cent CaOX, 10 wt. per cent CaCO3 and equivalent undoped samples. Results confirmed the preferential P-incorporation into a glassy matrix in the CaOX samples although some rare P incorporation into the metallic phase was noted. Experimental results, including comparisons with the CaCO3 fluxed and undoped samples, are discussed in view of the potential for CaOX flux for removing P (and potentially other impurities) from P-rich iron ores.

Nov 8, 2021

Thank you and good morning. I am delighted to be here and to see so many of my colleagues and competitors. The general topic of this week's conference - World's Best Practice in Mining and Processing - suggests a focus on mining and processing. I am somewhat of a `jack of all trades and a master of none'. But I'm not even a jack when it comes to mining and processing technology and practices, and so I will leave those topics to speakers better 'qualified than I. Instead, what I would like to do is give you my thoughts on the best management practices of mining. You see, the times are changing for the mining business. There is great uncertainty in our industry. Anyone who received their education in an English-speaking school probably remembers the famous poem `Invictus' by William Ernest Henley. The two most famous lines from that poem are, if you remember, `I am the master of my fate; I am the captain of my soul'. The fact of the matter is that the metals industry, including the copper industry, is not the master of its fate. To a great extent we're at the mercy of forces over which we have little control, such as the world economy or political situations in individual countries. The copper industry is like a surfer at Manly - we can't influence where the wave is going; all we can do is stay in front of the curl and on our board. Historically, discovering, developing and processing ore reserves were the primary facets of our capital intensive business. To stay competitive today, we must invest equally in intellectual capital - our employees - in order to succeed in the face of economic, regulatory and political challenges and global competition (Schonberger, 1986). Everyone seems to have a different theory about being competitive. A lot of people use sports analogies when talking about competition. Others, like American businessman and former US presidential wanna-be Ross Perot, take a more interesting approach. In Mr Perot's hypothetical corporation, competition is a lot like having a snake in a factory. If someone sees a snake, the first thing they do is create a committee on snakes. Then, the committee on snakes meets and discusses the problem for a couple of years. The most likely course of action is nothing. Everyone figures that the snake hasn't bitten anyone yet, so they just let him crawl around the factory floor. Perhaps a vice president of serpentine affairs is appointed to continue watching the snake - making sure it doesn't grow. Ross Perot sees it a little differently. In his corporate world, business needs to build an environment where the first guy who sees the snake kills it. Of course in our industry, we better make sure the snake isn't on an Endangered Species List before we go after it! I am not going to talk about competition and competitive forces in terms of sports or snakes, but I would like to share some thoughts with you about how the mining industry can better utilise competitive thinking to get ahead and stay there. You may be wondering how an executive from a 160-year-old company could know much about competitive spirit, but the founding ancestors of Phelps Dodge were wizards at identifying

Jan 1, 1995

By Bragg R, McMahon B, Lenton R

In 1992 environmental audits were carried out at seven coal mines operated by Oakbridge Limited in the Hunter Valley and Lithgow areas of NSW. The audit reports recommended a course of action designed to improve the environmental management system already in operation at the mines. This program started with training in environmental awareness for the Board of Directors, and the development and authorisation of an environmental policy. On-going programs at each mine were expanded to include environmental awareness training for all 2000 employees at the mines, and the development of a 20-module environmental training program which included air, water, soil and noise management, oil and chemical handling, sampling and monitoring, rehabilitation techniques and many more. Environmental incident reporting was introduced, and a system of reporting from the coal face through individual mine site environmental committees, to a Corporate Environmental Committee and up to the Board Environmental Committee became an effective part of a due diligence program. The Board resolved to undertake external independent environmental audits every two years, with internal reviews in the alternate years. An Environmental Management Group was formed, consisting of four internal environmental personnel and Oakbridge's appointed environmental consultant, to effectively resolve many of the environmental issues facing the Group. This program is continuing to evolve as an industry leader in environmental management Practice.

Jan 1, 1995

By Sturgul J. R

The South Middleback Ranges (SMR) operation involves the develop- ment of iron ore resources at the Iron Duke mine in the South Middle- back Ranges to replace the Iron Baron mine whose reserves are nearing depletion. The Iron Duke mine will be developed by contract to the stage where it can continue operation at full production when Iron Baron is closed. As part of the mine planning of the operation a GPSS computer simulation model was written to determine equipment requirements. The model simulated the operation of the mine with trucks transporting ore and waste to the appropriate destinations and producing a blended product in the stockpiles. A loader and two trucks would transport ore from the stockpiles to the crusher for one shift per day. The simulation shut the operation down at crib, morning tea, shift change and weekends, and also on the third shift each day. It also modelled operating delays. The results gave equipment operating hours and total output of each material type. The model was modified to produce different outputs from the mine and could be used to determine the most productive shift arrangement.

Jan 1, 1989

By M Logsdon, T R. Clark, T I. Mudder

Oxidation of pyrite and other metal sulfides is accelerated by the activity of acidophilic iron- and sulfur-oxidising microorganisms. The ideal biocide for controlling biocatalysed acid rock drainage (ARD) would be inexpensive, inhibitory toward sulfide-oxidising bacteria at low concentrations, relatively non-toxic toward non-target organisms, degradable in the environment outside the zone of application, stable and long-lived in the impacted environment, sufficiently mobile to penetrate into piles of waste rock or tailings, and effective regardless of the metal sulfides present. A potent agent for combating ARD that fits these criteria is the thiocyanate anion (SCN-). The objective of this study was to determine the effectiveness of thiocyanate in controlling or preventing ARD within several types of sulfidic waste rock and tailings. Results were evaluated within a context encompassing process water and solids management strategies employed at different precious and base metal mines. Sulfidic rock was treated with solutions of potassium thiocyanate and subjected to accelerated weathering tests in lab-scale humidity cells, trays, and columns. Certain tests also utilised solid phase copper thiocyanate (CuSCN) to evaluate a ærelease on demandÆ strategy. Leach solutions were analysed for parameters indicative of ARD including pH, redox potential, conductivity, acidity, sulfate, iron, and certain heavy metals. Two larger scale field tests were also initiated by personnel at separate mines using, in the first case, ore containing a pyritic component in large columns and, in the second case, waste rock containing base metal sulfides in lined pits. Humidity cell tests showed low concentrations of thiocyanate solution applied to pyritic waste rock could reduce ARD formation by 90 per cent or more compared to untreated controls, with the residual release of ARD components (eg sulfate, Fe, acidity) probably reflective of strictly chemical oxidation of the sulfides by molecular oxygen. Thiocyanate applied at a concentration of 22 mg/kg to waste rock from a base metal mining operation in large laboratory scale columns reduced acidity and sulfate release by 75 per cent to 80 per cent compared to untreated controls. This extent of reduction in ARD may not meet discharge water quality criteria, but has the potential to significantly reduce lime consumption and sludge production in a conventional neutralisation facility. The use of a solid-phase metal thiocyanate compound (CuSCN) at a dosage of 194 mg/kg pyritic ore resulted in the following per cent reductions in leach solution parameters in comparison to controls: sulfate (78 per cent), acidity (93 per cent), dissolved Fe (99.4 per cent), and dissolved arsenic (99.9 per cent). This compound has the further advantage of being relatively stable until needed, dissolving only in the presence of an acidic and oxidising ARD solution. If this line of investigation progresses favorably, it offers the possibility of an ARD prevention technique that may be applicable in some settings. Mine-site pilot scale tests with pyritic ore resulted in reductions in sulfate (56 per cent) and Fe, As (66 - 68 per cent). In sum, thiocyanate at relatively low concentrations dramatically reduced ARD from sulfidic rock in a simulated heap. The pilot test using waste rock containing base metal sulfides has begun only recently. A preliminary process design and cost estimate was made for fullscale application of thiocyanate to waste rock at a hypothetical gold mining operation producing 5000 tpd of ore and 10 000 tpd of sulfide containing waste rock. The combined capital and operating costs for the full-scale thiocyanate application facility were about $US 0.25/tonne of waste rock and $US 0.50/tonne of ore. Although thiocyanate is readily available commercially, it also occurs in process solutions associated with certain types of mining processes. Such solutions after selective treatment might be recycled to sulfidic waste rock or tailings, rather than being treated for thiocyanate degradation.

Jan 1, 2003

By White A, Price G

The main assets of a mining company are its orebodies; the second are the people who find and use them.The graphs in Figure 1 were derived from a paper by Rob Macdonald of Rothschild Australia presented to The AusIMM Centenary Conference in Adelaide earlier this year. They show that the value of the industry on the Australian Stock Exchange halved over the past decade, despite the re-investment of capital equivalent to its full market capitalisation. Why is this so? The average dividend yields for the ASX Mining Index was never above five per cent during that period and barely averaged 2.5 per cent. Why then is $Ai million capital re-investment per employee since 1960 not enough to generate a rate of return to investors better than lousy bank interest? Do the investing public no longer regard our industry's assets to be world class?

Jan 1, 1993

By S Prakash, M Danish, D Kumar

The green energy transition is speculated to cause an increase in the demand for raw materials while recycling rates are improving; discoveries are required to maintain supply. Geological remote sensing offers a cost-effective way of exploring mineral resources. While satellite and airborne imaging are routinely used for exploration targeting, a gap remains at the outcrop scale. Hyperspectral imaging (HSI) is advantageous for large-scale regional mapping, typically performed from satellite or airborne platforms. Accurately mapping geological lithologies remains challenging in inaccessible areas, such as rough terrain or mine sites. Proximal sensing techniques can boost geological activities’ reliability, safety, and efficiency in exploration or during mining activities. It also generates objective, reproducible results and valuable raw data that can be archived, further processed, and re-interpreted. Ground-based hyperspectral imaging of outcrops has steadily increased during the last decade due to sensor development and better processing routines. There is often a big technology gap related to mineral mapping, integration of images and spectra (reduction in manual identification of minerals and types) and hyperspectral data visualisation through remote sensing. TEXMiN Foundation, in collaboration with its industry partner Dassault Systemes Foundation, carried out the project, ‘Developing Hyperspectral Image Processing and Analysis, build a rich library of Hyperspectral images of a vast range of minerals from India which will help in increasing prediction accuracy of mineral deposit for mining exploration’.

Sep 1, 2024

Since 1969, a substantial number of geophysical methods have been applied in the search for porphyry copper and mesothermal type -sulpha-de deposits. These have assisted with geological mapping as well as the definition of various sulphide depos-its. The application of these methods at the Frieda-Nena deposits, Papua New Guinea, can be used as a case study for exploration in other parts of New Guinea.In 1993, Highlands Gold Limited carried out an intensive geophysical program over the Nena deposit. The methods employed included, CSAMT (controlled-source audio magneto-tellurics), airborne and ground elect-romagnetics, IP/resistivity and ground magnetics. The magnetic method was used as a regional mapping tool as well as a way of mapping alteration zones over both the Nena and Frieda River copper deposits. Electromagnetics, in part-icular FLAIRTEM, is a rapid reconn-aissance tool as well as a detailed mapping tool for the location of Nena-style massive sulphide deposits. IP/ resistivity is an expensive but most useful tool for mapping out Frieda porphyry copper style disseminated sulphides as well as Nena style deposits. It can be used to define drill targets in areas of difficult Access.a

Jan 1, 1994

By R Valenta

Most developing projects face a range of technical and non-technical challenges, and examination of development histories can potentially provide insights into improved approaches to project development. The Kestanelik project in the Canakkale region of Western Turkey was acquired by Chesser Resources Ltd in 2008. Turkey is a significant and growing source of gold production, with sector participation by both domestic and international companies. While the broad ranges of challenges faced by developing projects is well known, there are relatively few case studies in which the range of technical, environmental, social and governance challenges are presented in a single contribution. Recent studies of undeveloped complex orebodies have particularly shown the extent to which environment, social and governance (ESG) complexities contribute to project delays and failures. The Kestanelik project faced a full range of technical and ESG complexities, and provides an illustrative example of the associated challenges. CITATION: Valenta, R, 2018. A case study of technical, social and environmental challenges for a gold project development in Western Turkey, in Proceedings Complex Orebodies Conference 2018, pp 73–74 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

Many volcanoes in western Melanesia have tectonic settings and rock compositions that do not conform to conventional models of arc- trench systems. Part of the reason for this may be that in an environment of rapid tectonic change mantle source regions bear the imprint of former subduction even though subduction has now ceased. Results bearing on this concept and on other important aspects of Plelit nesian v ican ism and tectonics, were obtained in 1982-1986 from >e,:eral marine - geoscience studies in the re,,ii n

Jan 1, 1987

Maximising margins in today's competitive international commodity markets demands superior productivity. This requires more than selecting the best equipment. It requires continually improving the efficiency of production, commercial, marketing and administrative processes under the control of solid modern management systems.This paper introduces an integrated way of working that includes proven management systems for successfully changing work practices and attitudes, developing managers and increasing accountability. It introduces a proven methodology for systematically involving people in sustained true continuous improvement of processes for maximising productivity, safety and revenue while minimising costs.

Jan 1, 1998

After four or so long years at university, where life revolves around lectures, assignments, and drinking coffee strong enough to keep you awake for five nights in a row to finish your thesis, preparing yourself for employment is not an ea

Jan 1, 1994

By X Li, H Alehossein

The oscillating disc cutter (ODC) is an innovative technology for the continuous excavation of hard rock. This paper will discuss:the reasons for its development;its method of operation;current experimental results and mathematical modelling undertaken at the CMTE; andapplications in the mining and rock excavation industry.

Jan 1, 1999

For various reasons, the maintenance of shaft structures is becoming an increasingly important factor in the operation of underground mines. Deterioration mechanisms related to operation of the shaft are identified as corrosion, mechanical damage, fatigue damage and wear. Deterioration mechanisms related to rock movements are identified as vertical strain, ride vertical closure and squeezing. Analytical procedures for assessing this deterioration are discussed, and it is shown how acceptance criteria are developed and implemented. In order to track the deterioration of shaft structures, shaft inspections are undertaken, but the information is often not well documented. Formalised procedures for capturing and recording information, and then processing the information are presented. Finally, two case studies are briefly described to illustrate how these procedures have been implemented in practice, and what benefit has accrued to the mines concerned.

Jan 1, 2005

The Ausmelt Catalytic Waste Converter (CWC) has been developed for use in the treatment of industrial wastes and for the recycling of secondary materials. Ausmelt Technology uses a top submerged lance system within a versatile and efficient slag bath reactor. High temperature pyrometallurgical reactions are carefully controlled within an oxidised molten siliceous slag such that metals can be extracted from waste feedstock for recycling, with non-volatile elements reporting to the slag, usually as oxides. Modification of the slag chemistry results in a final slag product that is stable, vitrified and is able to pass standard leach tests such that it is safe to discard or be used in civil engineering applications. Toxic components in the wastes such as organohalides can be completely destroyed and are prevented from reforming. Waste to energy conversion is practiced by the addition of a heat exchanger/steam generator in the converter offgas system. The Ausmelt CWC has been used for recovering zinc from residues and slags, treating spent potliner (SPL) from the aluminium industry and a wide range of electronic and other potentially valuable waste materials. Methods of monitoring the exhaust gases at different stages in the CWC gas handling system are discussed. The assay of these gases prior to emission is used to assist in the control of the converter chemistry to ensure the complete oxidative breakdown of the feedstock.

Jan 1, 2002

By Merritt RR

The equilibrium phase relations in the Fe- Mn-Ti-0-S system were established at 1380 and 1485 K. The elemental distributions between the equilibrium phases were obtained by chemical- ly analysing selected samples from the phase study. The results are considered in relation to the coal reduction process for upgrading ilmenite. The beneficial effect of adding sulfur to a kiln that uses a manganese-rich feed is ex- plained by the formation of a metal-sulfide solid-solution phase that removes part of the manganese from the oxide system. The optimum conditions for operating the reduction kiln are determined, and the practical need to operate the kiln at other than optimum conditions is explained. It is shown how the experimental data can be used to predict the best compromise conditions for reduction and the resultant purity of the product.

Jan 1, 1980

By Coxhead B. A, Brandt B. A

The geological exploration and evaluation of coal reserves involves the appraisal of very large amounts of data. Computers afford an ideal means of handling and manipulating the data, thereby avoiding the laborious and expensive method of manually compiling the logs in full descriptive language. The Minad system of computer storage and retrieval of geological and analytical data is particularly suited to the description of cores and cuttings from exploration drill-holes. The encoded data is arranged in a 120-column computer output sheet format; descriptive geological information in a 54-column geolog and analytical information in a 64-column assaylog. The acquired data is quantitative, uniform and relatively complete and can be selectively retrieved for processing by a wide range of specialized computer programs developed for the coal mining industry. Visual retrieval of data for manual processing is facilitated by the use of simple codes and logical word abbreviations.

Jan 1, 1977

There are significant Mineral Resource and Reserve reporting challenges facing a mining company operating in the global arena. This paper specifically examines the Mineral Resource and Reserve reporting challenge facing BHP Billiton. The changing regulatory environment creates a significant challenge for global mining companies when reporting Mineral Resources and Reserves. The development and implementation of internal policies and standards for collecting and collating resource and reserve information is required for corporate governance, however the challenge is then to report this information publicly in such a way as to comply with the various codes and requirements in the many jurisdictions in which the company is required to report. The move to an International Code is not only desirable but is an essential requirement in todayÆs global market. The agreement to report using a single code internationally is however only the first step. A truly practical international reporting system must have common definitions and guidelines for interpretation as well as an international approach to the definition of a Competent Person, and even more importantly a common acceptance of that code by the relevant investment regulatory bodies. Without the universal acceptance of the concept of an international reporting code by the major regulatory bodies, implementation of such a code will be limited. With the major global mining companies seeking to raise capital in the USA, the worldÆs largest capital market, the Securities and Exchange Commission (SEC) and its approach to reserve reporting is becoming increasingly important. The development and implementation of an International Code must gain the support and acceptance of the SEC if it is to be successful.

Jan 1, 2002