Search Documents

By Rodrigo Toro, Mario Delisle, Claudio Zamora

"The mining market is researching innovative methods to train the workforce for mining which is normally extremely difficult to get. Thus, the dynamic simulation-based technologies become an essential pillar to educate and train the inexperienced staff at the pace required by this industry. Even if Operator Training Simulator (OTS) systems are commonly used in most of industries, knowledge transmitted to operators are unfortunately not ""capitalized"" in general. The OTS systems are usually delivered as a single hardware and software platform and very little as a full service long-term.In this article, an integrated solution to increase the efficiency of the operators is proposed. This solution is based on the combination of dynamic simulation, processes knowledge, virtual reality and the knowledge capitalization through the creation of simulation scenarios and e-learning. The Codelco Ministro Hales plant simulation project for a copper concentrator plant is presented as a real life example.IntroductionDynamic and real-time process simulation have proven to be a must in the development of greenfield projects, providing mechanisms to design and test controls design, interlocks, start-up, shut down sequences and operator training, among others (see (McMillan, 2006) for further details). Early adopters of this technology were utility power plants; in the petrochemical industry have become a standard, and in the mining industry the use of dynamic simulations is growing, especially in new projects and training of operations personnel for the adoption of best practices and new technologies, see (Nikkhah & Anderson, 2001) and (Toro, Ortiz, & Yutronic, 2012).This paper outlines a solution that utilizes dynamic simulations as the base of an integrated platform for operational effectiveness, which takes into account the current scenario of new mining projects and operations, where high turn over rates and needs of specialized workforce have given a special value to this kind of technologies."

Jan 1, 2015

By S. H. Miller

Biodegradable hydraulic fluids can save tens or hundreds of thousands of dollars in fines and clean up costs in the event of a hydraulic fluid leak or spill. When properly selected, applied, maintained and monitored, a biodegradable fluid will have a long useful life and will protect equipment as well as or better than conventional petroleum based hydraulic fluids.

Jan 1, 2000

In a previous paper of this series (1) ,t it was shown that during the creep of single crystals of lead, deformation proceeded to some extent by means of slip on the octahedral plane. This was demonstrated by the formation of slip lines on the surface of the specimens. At first, a few broad bands appeared after a small amount of extension had taken place; then, as extension proceeded, more and finer lines made their appearance until the whole of the specimen surface was covered.The present paper deals with the process of deformation of the creep specimens as revealed by X-ray examination..By the use of this method, the changes taking place in the crystal structure can be observed.EXPERIMENTAL METHODThe method of preparation of the specimens, their size and the purity of the lead employed have been reported elsewhere (1). At frequent intervals, the specimens were dismantled from the test rack and X-ray back reflection photographs were taken. The specimens were so marked and set up on the X-ray machine that the same spot on the specimen surface was always examined.Copper radiation was employed, the tube voltage and current being 45 kV. and 25 m.a. respectively and the exposure time 2 hrs. The slit diameter was 1 mm.

Jan 1, 1941

By S Mundell, A Atkins, S van de Water

Geoscientific information management enables the capture, management and delivery of the original geoscientific observations and measurements of the earth’s natural resources. However, original observations and measurements are worth nothing if the quality and integrity of the data can’t be guaranteed. Geoscientific information is one of the fundamental assets enabling miners to make confident and accurate business decisions, whether that is defining a resource model, performing reconciliation, delivering ore reserve reports or meeting environmental compliance requirements. Without access to reliable, validated or verified data it increases the risk of miners using incorrect information for reporting and compliance. Industry codes, such as JORC, or government regulations, such as environmental compliance requirements, must be adhered to and companies should be able to confidently report to these standards. Without having a robust information management framework in place, it becomes a challenge to make trustworthy decisions, report confidently and reduce the risk of non-compliance. As a key initiative, good data governance should form one part of a miner’s information management strategy. Within the mining industry it is common for companies to only consider technology tools as the key focus for compliance whereas a mature information management focus will additionally consider people and process. All three pillars are critical for a miner to have confidence in their data driven decisions. This paper discusses an industry framework for best-practice geoscientific information management based on the observations gathered from analysing data management practices within the mining industry. It focuses on how the three pillars of people, process and technology are crucial elements to improve operational decisions and ensure companies are compliant.

Nov 8, 2021

By R W. Hutchinson

Cupreous pyrite deposits in Cyprus have many geologic similarities to Canadian massive sulphide copper-zinc ores as well as certain significant differences. A comparison of the Cyprus and Canadian deposits indicates a complex genetic history for the latter and suggests that their origin should be re-examined. The Cyprus ores occur in subaqueous extrusive rocks near and at the top of a Cretaceous volcanic pile or igneous complex. The rocks have not been deformed, nor have they been deeply buried or deeply eroded. Apparently the ores formed near or at surface in the top of the volcanic pile by a volcanic-exhalative process and from an ore-fluid of volcanic derivation. The Canadian deposits are of comparable composition and have similar geologic set-tings, but occur in the most ancient Precambrian rocks. Their enclosing Keewatin greenstones have, in most places, been deformed, regionally metamorphosed and invaded by granitic intrusions. Comparison suggests that the Canadian ores also formed initially near surface in ancient Keewatin volcanic complexes by a syngenetic, volcanic-exhalative process. Subsequently, during orogenesis, they were deformed, remobilized under conditions of elevated pressure-temperature and re-emplaced as epigenetic bodies into

Jan 1, 1965

The Zeehan field has yielded over 190 000 tons of lead and 26,000,000 oz of silver. Moh of the production took place between the initial discovery of silver-lead ore in 1882 and 1920, and the greatest part was extracted from fissure lodes in the Proterozoic to (?) lower Cambrian rocks. It is demonstrated that the prosperity of the mines relied upon the silver content, which is apparently highest in these beds, particularly where spilitic rocks are associated with them. In contrast, galena occurring in orebodies emplaced in the Gordon Limestone is low in silver.Most of the workings are relatively shallow due in some cases to enrichment related to erosion surfaces.Fault zones within a complex anticlinal structure exposing the Proterozoic to (?) lower Cambrian formations appear to have been major factors in the control of mineralization.

Jan 1, 1968

By D Craw, P Upton

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Southern Alps of New Zealand and the mountains of Taiwan are both young transpressive orogens characterised by rapid uplift and exhumation, high heat flow and vigorous surface processes. Comparing and contrasting the two provides an ideal framework through which to explore the structural and lithological controls on fluid and gold mobility during collisional deformation. Both have two fluid flow systems centred about their drainage divide with shallow topographically-driven meteoric water above a deeper flow system dominated by mineralising rock-exchanged fluids. Despite similar tectonic settings, the distribution of heat flow, hot springs and veins in the two orogens are different. Taiwan has higher heat flow, distributed hot springs and localised veining whereas the Southern Alps have a narrow heat flow anomaly, localised warm springs and widespread veining. We use three-dimensional numerical models to evaluate key parameters that affect fluid flow and gold mineralisation. Models show that differences in crustal strength and thickness affect the locus, scale and rate of crustal fluid flow and hence influence gold deposition at a variety of scales. We explore how surface topography can lead to localised changes in the stress state, facilitating the switching of principal stresses and hence vein orientations.CITATION:Upton, P and Craw, D, 2015. Modelling structural and lithological controls on the mobility of fluids and gold in orogenic belts – examples from New Zealand and Taiwan, in Proceedings PACRIM 2015 Congress, pp 189–192 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By C. R. Julian

THE large pyrites ore-bodies, the underground mining of which is to be described, are situated at Rio Tinto in the Province of Huelva in Southern Spain. The situation of the different ore-bodies with relation to one another is shown in Figure 1. It will be seen on the plan that the strike of the ore-bodies is approximately east and west. The geology of the district has been very fully described by Dr. D. Williams (1), so that for the purposes of this paper it will be sufficient to give briefly the salient features o each of the two larger ore-bodies which are being mined by underground methods at the present time. (a) San Dionisio.-This ore-body is the largest single deposit in Rio Tinto, having on its upper levels a length of 3,500 ft. On the upper levels the average width is approximately 200ft. but in places on the lower levels there is a width of 900ft. of un broken pyrites. Diamond-drill holes, without running out of ore, show the ore-body to persist to a depth of at least 1,600 ft. The ore-body in the upper part lies between slate and porphyry walls, but in depth is enclosed in porphyry walls. (b) South Lode.-Faulting is considered to be responsible for the break in the solid ore between South Lode and San Dionisio. On the upper levels, the South Lode ore-body has an unbroken length of 4,000 ft. The massive pyrites has a maximum width of 300ft. and an average of about 100 ft. Ore has been proved to a depth of 1,000 ft., at which depth the ore-body is much reduced both in length and breadth. This ore-body, to the depth at which it has been proved, lies entirely between slate and porphyry walls. The South Lode and the San Dionisio ore-bodies are mined both by open-cast and by underground methods. There is evidence that these mines have been exploited intermittently during the last 3,000 years; but, as is to be expected, no records are available of the tonnage mined prior to the time of purchase by the present company.

Jan 1, 1940

By Yunnen Chen

The test and use of natural materials as biosorbents for the removal of heavy metals from industrial wastewater is under constant development. In the present study, the biosorption capacity of waste microzyme was studied for cadmium The cadmium removal study has been carried out batchwise where the influence of physico-chemical key parameters such as pH value of solution, contacting time and initial cadmium ions concentration have been considered. The influence of metal ion concentration was evaluated and the results were fitted using adsorption isotherm models. The kinetic of cadmium biosorption was also investigated. The maximum percent removal was attained at the pH 7.0 after about 30 min. Waste microzyme was a potential biosorbent for the removal of Cd(II) from the effluent of electroplating industry.

Jan 1, 2009

By Francisco Alberto Marreiros da Rocha Filho

A corrosão é um fenômeno que está intimamente ligado à integridade dos metais e de suas ligas. Esta ocorre de diversas formas, uma das principais é a corrosão localizada na forma de pites, objeto de análise desse estudo, que visa estabelecer um comparativo entre as curvas de polarização cíclica de algumas ligas ferrosas e não ferrosas, ensaiadas em solução de NaCl 0,6 M, mostrando a agressividade que a solução exerce sob cada uma das ligas. Os materiais analisados nesse estudo foram os aços inoxidáveis AISI 304, AISI 444, super duplex ASTM A890/A890 M Grau 6A, o aço carbono AISI 1030, o alumínio comercialmente puro, o cobre eletrolítico e a liga zircaloy- 4. Inicialmente foram medidos os potenciais de corrosão (Ec) de cada liga através do monitoramento do potencial de circuito aberto. Foram realizados os ensaios de polarização potenciodinâmica cíclica em cada liga, comparando o aspecto superficial antes e depois do ensaio através de micrografias óticas, possibilitando que fossem observadas as diferenças entre cada material quanto à resistência à corrosão por pites. Observou-se que algumas ligas não apresentam passivação como o caso do alumínio comercialmente puro, e outras apresentaram regiões passivas e histereses bem definidas, ficando evidente que, dentre as ligas analisadas, o aço inoxidável super duplex ASTM A890/A890 M Grau 6A apresentou os melhores resultados frente aos efeitos agressivos dos íons Cl- presentes na solução, sendo o menos suscetível à corrosão por pites.

Aug 17, 2017

By Herbert A. Franke

ANY analysis of the aluminum situation, particularly of the factors involved in the current shortage of the metal, must consider the rapid march of events since the Munich fiasco of September 1938. At the end of 1938, the sole domestic producer of aluminum had more than a year's supply of metal on hand, having added 50,500 tons of output to stocks during the year. Not until war had been declared between the United Kingdom and Germany in September 1939 did the United States begin to make serious preparations for defense and a limited national emergency was proclaimed. Congress reflecting popular opinion, was not disposed to spend huge sums for armaments in 1939, and although 31,413 tons of aluminum was withdrawn from stocks. 107,500 tons was still on hand at the end of the year. When the President initiated a 50,000-airplane program in May 1940 the country was astounded, as previous Congressional authorizations of approximately 6000 planes for the Army by July 1911 and 3000 for the Navy by 1914 had been considered adequate.

Jan 1, 1941

By N. Hiroyoshi, R. D. Corpuz, M. Ito, Hokkaido University, C. B. Tabelin, S. Veerawattananun

"Acid mine drainage (AMD), the very acidic and heavy metal-contaminated leachate generated when pyrite-bearing rocks are exposed to surface oxidizing conditions, is a serious environmental problem encountered after the closure of mines and mineral processing operations. In this study, we investigated the effects of soluble phases and metallic oxides, which are commonly found in strongly weathered pyritic wastes, on pyrite oxidation. Strongly weathered pyrite containing melanterite (FeSO4·7H2O) as the main soluble phase was obtained from Furikusa mine, Japan. The sample was washed using two methods to vary the relative amounts of melanterite in the sample. The effect of metallic oxides on pyrite oxidation was evaluated using ultrapure hematite suspensions. Our results showed that under acidic conditions, the effect of soluble salts on the oxidation of pyrite was stronger than hematite. More thorough washing of the sample resulted in the formation of an arsenic-bearing iron-oxyhydroxysulfate coating that minimized pyrite dissolution. This oxidized layer became relatively thicker and mechanically stronger when hematite was introduced after the more thorough removal of soluble salts. Characterization of this “coating” coupled with geochemical modeling suggest that it is most probably composed of two materials: schwertmannite and scorodite. Based on these results, a new approach to suppress pyrite oxidation by directly using iron-oxyhydroxysulfate as coating material is introduced.INTRODUCTION Acid mine drainage (AMD), the very acidic and heavy metals-contaminated leachate produced in closed/abandoned mine sites (Evangelou, 1995), mineral processing and coal cleaning tailings (Evangelou, 1995), and tunnel construction waste rocks (Tabelin and Igarashi, 2009, Tabelin et al., 2012), is one of the oldest and probably the most serious environmental problem of anthropogenic origin. When released to the environment, it rapidly pollutes river, soil and groundwater systems leading to the destruction of affected ecosystems. AMD is produced when pyrite (FeS2), one of the primary gangue minerals in sulfide ores and coals, is exposed to oxidizing conditions as illustrated by the following reactions:"

Jan 1, 2016

Up to 19 chemical parameters were studied in flotation pulps in six Australian lead-zinc concentrators with the aim of obtaining a better understanding of the nature of, and changes in, the chemical environment. This paperdiscusses collector residuals, metal concentrations in solution, and other parameters.Collectors used in the plants studied were various xanthates, Z-200, and Aerofloats. Xanthate residuals varied in different ways in most plants. However the general trend was for residuals to be at the O· 5-2 p.p.m. level in lead flotation and O· 5 p.p.m. or less in zinc flotation.Aerofloat residuals were also variable but in the plant concerned were at a much higher level (8-10 p.p.m.) than xanthate residuals. Z-200 residuals were in the 10-20 p.p.m. range and it was found that the Z-200 added to zinc flotation was reporting in dam return water and entering lead flotation.Copper concentrations in solution were negligibly low in those plants where cyanide was not used. When cyanide was used, copper was at the 5-20 p.p.m. level and appeared to be present as Cu(CN)-2. However the hiocyanatepresent may be important. Xanthate was also present in these solutions.Zinc concentrations ranged from 0·1 to 800 p.p.m. in different plants. The general trend was for the zinc level to be highest in the grinding circuit and to drop during flotation. However there was always an increase in zinc concentration when copper sulphate was added, even tho.ugh this incre.ase was not permanent, and the increase was greater with higher copper sulphate additions.The manganese concentration also increased appreciably during copper-activation of marmatite. In some plants lead concentrations increased from 0·1 to 1 p.p.m. during activation of marmatite.Calcium concentrations (20-1200 p.p.m.) and magnesium concentrations (10-600 p.p.m.) tended to be fairly stable in each circuit.

Jan 1, 1970

By D Brooks, S Gunn, T Perkins, J Siliezar

Ernest Henry Mining (EHM) is a copper, gold and magnetite mining and processing operation located 38km north east of Cloncurry. The EHM ore body has an average grade of 0.9% copper (chalcopyrite), 0.5g/t gold and 22% magnetite.Open pit mining commenced in March 1998, but EHM transitioned to underground mining in December 2012, extending the life of operations beyond 2024. The underground mine currently produces up to 3Mt/year of ore, hauled up a decline by truck. This figure shall double in 2014 with the completion of a 1000m shaft. The EHM Concentrator has a nameplate capacity of 10Mt/year. In June 2011, Xstrata Copper acquired the Mount Margaret resource to supplement underground production and utilise the full capacity of the Concentrator. The Mount Margaret Mining (MMM) operation was established to develop the five deposits making up the resource by way of open pit mining.Copper concentrate is produced by the EHM Concentrator via grinding, flotation and dewatering circuits. The grinding circuit comprises a SAG and ball mill in a closed AB configuration. Flotation consists of a rougher train, regrind and three stages of cleaning, with the tail from the first stage reporting to the tailings thickener.The mineralogy of the MMM ores is complex, comprising fine textures of active pyrite, copper oxides, native copper, clay and secondary copper sulphides. This paper provides an overview of the metallurgical test work completed to forecast the performance of the MMM ores through the EHM Concentrator and identify flow sheet modifications for maximising copper recovery and producing a saleable concentrate. A discussion of the challenges experienced in the plant to date follows.CITATION:Gunn, S, Siliezar, J, Brooks, D and Perkins, T, 2013. Adapting the Ernest Henry Mining concentrator to process the Mount Margaret ores, in Proceedings MetPlant 2013 , pp 347-370 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

By T. G. Carter

Support system design for tunnels and underground excavations has for many years relied heavily on the use of rock mass classification systems and the Hoek-Brown failure criterion as a means for characterizing rock mass behaviour. Because of their development, both the GSI system and the Hoek-Brown criterion admirably characterize most ?normal? rockmasses from the viewpoint of their behaviour for rock excavations. They, however, run into difficulties when applied at the two ends of the rock competence scale. This is largely because block size and incipient strength are such that rockmass behaviour in these domains tends not to be controlled by interblock shear strength but rather by material strength. At the low end of the rock competence scale (UCSi <<15 MPa and GSI generally <30) discontinuities play less of a role and rock mass strength tends to matrix strength. Similarly, at the high end of the scale (GSI >>65, mi>>15), because discontinuities are now widely spaced, block size becomes so significant that again, intact material behaviour rather than the fracturing becomes the dominant factor controlling rock mass strength. In this paper several case examples are presented to illustrate the application of the high-end (spalling) and low-end (weak ground) transition Hoek-Brown relationships proposed by Carter, Diederichs and Carvalho (2007) as a basis for better defining rockmass behaviour at the extreme ends of the rock competence scale.

Jan 1, 2008

Smart defense: that?s what the industry needs to play for the next four years, according to panelists at the 118th Annual Meeting of the Northwest Mining Association (NWMA), which met December 2-7 in Spokane, WA. The conference was well attended, with approximately 2,200 attendees, 244 booths in the two packed exhibition halls, and a rich offering of short courses, field trips, social events and technical sessions. Speakers at the packed legislative session articulated many of the frustrations felt by members of the mining community after the U.S. elections in November, and offered words of advice. Matthew Ellsworth, the new Government Affairs hire at NWMA, stated it best: ?Elections are like Christmas: you find out who?s naughty and nice ? and it?s always going to come again.?

Jan 1, 2013

By Bruce Vandenberg, R. Frank Chiappetta, John Foley

Recent advances in solid-state, field portable, fast framing compact video camera systems and PC based frame capture hardware now allow blast imaging up to 1000 frames per second. Up to 4.1 seconds of data can be captured directly into the unit, downloaded to a PC or archived to a standard VCR without data compression. Since no film processing is involved, motion analysis can be performed instantly and on-site within a few minutes. This paper will describe the design features and applications of the MotionMeter system and compare these with the analogous aspects of film-based cameras and other systems. Of all blast monitoring systems and techniques available today, high-speed motion picture photography and videography still remain as the most valuable, stand alone, diagnostic techniques for troubleshooting and evaluating full scale blasts in the mining and explosives industries. High-speed image data, coupled with information obtained from other instrumentation systems, such as continuous velocity of detonation recorders, laser surveying systems, refraction and ground vibration recording seismographs, etc., can eliminate many assumptions about what actually took place in a blast. Thus, diagnostic confidence in evaluating both excellent and poorly designed blasts is increased, and optimum blast results, (which are application dependent), are achieved considerably faster when compared to the trial and error approach of relying on strictly the experience factor. Applications include developing site-specific blast designs, decay equations relating burden, burden velocity and explosive energy, determining ground response times, reducing coal damage, quantifying backbreak, evaluating the effectiveness of sternming, checking delay detonator firing times, evaluating air decks and for studying general dynamics. Motion analysis is performed with a 2D and 3D software package developed specifically for video analysis, but is also directly applicable to film analysis when using a digitizer. Dimensional controls, lens aberration, field set-ups and camera orientation are all automatically corrected for with matrix analysis.

Jan 1, 2000

By B. W. J. van Rensburg, M. J. Schmidt

Bulk materials handling systems are extensively used in the mining and minerals industry, where a fairly high incidence of structural failure is experienced, notwithstanding design compliance with appropriate standards. A number of case studies are explored to demonstrate how insufficient controls or protection systems have contributed to structural failures on mobile bulk handling equipment. The importance of design integration across engineering disciplines is highlighted. The revision of ISO 5049-1 (1994) is proposed to provide specific rules and guidelines pertaining to machine protection systems. It is further recommended that the structural design engineer of the original equipment manufacturer(OEM) fulfils a more prominent role during the final acceptance and handover of mobile bulk handling equipment, with specific reference to protection systems.

Jan 1, 2015

By Ralillie Lopes Carvalho

O presente trabalho apresenta um estudo da influência do tratamento de nitretação a plasma sobre a dureza de lâminas utilizadas em prensa-facas de um picador de toras industrial. Tais peças são fabricadas em ligas com alto teor de Cromo e Carbono, assemelhando-se quimicamente aos aços para trabalho a frio AISI da série D. Para o estudo em questão, pequenas amostras das lâminas receberam tratamento térmico de têmpera e duplo revenido,e posteriormente foram nitretadas a plasma por 30, 90, 180, 360 minutos, em temperatura de 450°C, com pressão fixada em 2 Torr e mistura gasosa de 20%N2 e 80%H2. Logo após foram realizadas análises metalográficas com auxílio de microscópio óptico, ensaio de dureza superficial e perfil de dureza com microdurômetro em escala Vickers. Os resultados mostraram que para todos os tempos de tratamento houve endurecimento superficial em relação ao material não tratado, onde o tempo de 180 minutos propiciou a formação de camada com maior valor médio de dureza superficial “1171,20 HV”.

Aug 16, 2017

By B. M. Larsen

Jan 1, 1948