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By D. T. Pritchard

"Introduction""No accounting system is very good, and all of them are infinitely variable*.”The purpose of this chapter is to discuss those facets of a typical accounting system which are most commonly encountered by operating managers in mineral processing plants. However, before concentrating in any detail on these it is important to understand the broad purposes and basic techniques of any accounting system in any major business.The three broad purposes of an Accounting System are:- Administering, controlling, and recording the flow of cash in and out of the business. Cash is, of course, converted into other assets (or stores of value) such as inventory, plant and equipment, etc. These assets also have to be administered, controlled and recorded.- Internal reporting to Management for information, for control, and for use in making business plans and decisions. - External reporting to stockholders, government, lenders and other outside parties.In this chapter we shall organize our discussion of accounting practice in mineral processing plants around these three purposes of accounting and focus in some detail on specific practices and techniques with which operating personnel will be routinely involved. This chapter is divided into the following: Accounting Basics; Administration, Control and Recording of Cash Flows; Internal Reporting; Planning and Budgeting; Cost Control; and External Reporting."

Jan 1, 1989

By R. C. Beard

"Heap leaching, currently being applied in the treatment of low-grade ores in the south western United States, is shown to have potential for use in north western Ontario. The history and operation of the process are described, and cost comparisons are given.IntroductionHeap leaching is a simple, low-cost method of recovering gold from low-grade ore. Although it is not currently being used in Canada on a production scale, it is being used extensively, and successfully, in the southwestern United States as well as elsewhere in the world. Especially suited for large deposits of very low -grade ore, it also appears to be practical for use on small, high-grade deposits because it avoids the high capital costs of mills. Eveleth (1980) and others suggest that the capital and operating costs required for heap leaching are approximately 20% and 40% respectively of conventional milling methods.Northwestern Ontario is noted for its large number of undeveloped, small, high-grade gold deposits. Although there are a number o f larger and higher-grade deposits in the area as well, it is the relatively small undeveloped deposits which would benefit most from heap leaching, if it could be demonstrated to be a viable extraction method.To assess the significance of these small deposits, the Ontario Ministry of Natural Resources recently commissioned a consultants' study of the gold reserves in certain parts of northwestern Ontario. This report, titled ""Feasibility of Small-Scale Gold Mining in Northwestern Ontario"", by J.N. Neilson and R.C.E. Bray (1981, OGS Open File Report 5332), documents 106 known gold deposits having sufficient information to calculate gold reserves. A total of over 7.8 million tons having a weighted average grade of 0.19 oz of gold per ton were compiled in the proven, probable and possible categories, with an additional 8.2 million tons in the speculative category. Many of these deposits could be mined by open-pit methods."

Jan 1, 1983

By J. Peck, F. Brackebusch, M. Scobie

"A number of alternative strategies exist to improve narrow orebody stope productivity and safety through mechanization. Particular attention is given to one of these: the development of an in-stope mining machine. This paper summarizes those characteristics of vein orebodies in Canadian mines which are considered to govern such mining machine design. It then reviews past and current attempts to develop hardrock mining machines which could potentially be applicable to narrow stope widths.IntroductionSerious interest is mounting to exploit new technology in the development of methods and machinery to stope narrow, hardrock, orebodies. The motives relate not only to the foreseen need to maintain or reduce production costs, but also to considerations of manpower availability, safety, ground control, ore recovery and dilution. This also follows the demonstrated success of technology application in larger metal orebody stoping, where machine development has been seen to lead to improved productivity as well as the future prospects of continuous mining systems and eventual automation, e.g. ITH blasthole drill development and bulk mining. This paper deals in particular with machine design for ore fragmentation in narrow, hardrock orebodies. It is considered that such machine design closely interacts with the over-all stoping method design and that both require consideration in parallel to ensure success in mechanization."

Jan 1, 1990

By H. W. Kasaini, E. Bourricaudy, T. Larochelle

Rare Element Resources Inc., a U.S. based company, has developed a three-stage process for producing a +98% mixed REO powder from hard rock feedstock (-48 mesh, 2.9-4.8% REO) consisting of bastnaesite and ancylite minerals. Firstly, the whole ore is digested in chloride media at low temperature in counter-current flow mode. Secondly, the rare earths (REEs) are selectively precipitated as oxalates directly from an impure pregnant leach solution (PLS). Finally, significant amounts of free acid and water are recovered from the REE-depleted filtrate and subsequently recycled within the process. Excess heat from the oxalate calcination process is captured and reused in the plant. Due to the low leach temperature (45 ºC) and moderate acid dosage (240-297 kg/t, HCl), rare earth oxides (REOs) are preferentially leached out of fine solids leaving most of the base metals (Ba, Fe, and Al ) in the residue. Selective recovery of REEs from the PLS is achieved by mixing dilute oxalic acid (33% H2C2O4) and PLS at elevated temperature (85-95 ºC). The REEs plus thorium are precipitated as oxalates (REE2 (C2O4).xH2O) while the base metals are left behind in the barren filtrate. Multiple batch and pilot test results have confirmed that 50-80% of the oxalic acid can be recovered from the REE-depleted PLS through low-temperature crystallization (10-15 ºC). Typical leach efficiencies of critical rare earths at 45 ºC range from 85-99% (average 93%) while oxalate precipitation at high temperature increases the crystal size of RE oxalates (>450 microns, d80) thereby improving filtration. The economic benefits of this process include elimination of flotation and magnetic separation Capex and driving hydrometallurgical Opex down to $6- 7/kg, REO produced. As part of a comprehensive risk mitigation strategy, Rare Element Resources Inc has operated multiple pilot plants at SGS in Lakefield, Ontario, Canada to optimize counter-current leaching (CCL), REE oxalate precipitation (OXP), and thorium removal circuits. This paper presents pilot testing data from CCL and REE OXP circuits.

Jan 1, 2016

By R. N. Chakravorty

Early detection of spontaneous combustion is of utmost importance in underground coal mining to prevent major disruptions of production and to ensure a safer working environment. This paper presents the work done in developing a suitable system for the early detection of heating in a hydraulic coal mine. Laboratory studies on the products of oxidation for Balmer 10 seam coal showed that a significant amount of carbon monoxide is produced during the early stages of heating and that detection methods based on the analysis of other gases, such as hydrogen, ethane or ethylene, are not a better alternative for this coal. The four-point carbon monoxide monitoring system recently installed at the hydraulic mine is discussed in this paper. It is believed that by studying the trend of carbon monoxide concentration in the mine air, it will be possible to detect heating at an early stage. Field tests carried out so far have indicated that infra-red technology will prove to be a powerful tool in the hydraulic mine, particularly for locating hidden oxidation or fire in cracks, fissures, underground workings and coal outcrop areas before it spreads extensively. The project is jointly sponsored by EMR, CANMET, Mining Research Laboratories and Kaiser Resources Ltd.

Jan 1, 1978

By Jr. Watts, B. K. Cantrell, K. L. Bickel, J. F. McDonald

"A field trial was conducted at an underground gold mine to evaluate diesel fuel derived from soybean oil (soy-methyl-esters or “biodiesel”) as an alternative to commercial, low-sulphur, number 2 diesel fuel (D2). A 2.7 m3, 18-ton load-haul-dump (LHD) unit, powered by a naturally aspirated, indirect injection (pre-chamber), 100 kW diesel engine was used as the test vehicle. The LHD was equipped with a diesel oxidation catalyst. The LHD operated satisfactorily on the biodiesel fuel. Operators observed a slight decrease in power and an absence of black smoke.Diesel particulate matter (DPM) concentrations were monitored for a six-week period while the LHD was operated with either the biodiesel fuel or the D2 fuel. DPM concentrations were measured in the mining section’s clean air intake, exhaust and on the LHD. Reduction in DPM emissions was determined from the measured difference in DPM concentrations between the clean air intake and the exhaust. The biodiesel fuel reduced energyspecific DPM emissions approximately 75%, from 3.6 ± 1.8 g/kW-hr to 0.86 ± 0.27 g/kWhr. Time-weighted average DPM exposure, measured near the LHD operator, was reduced from 0.67 ± 0.13 mg/sm3 to 0.28 ± 0.12 mg/sm3, or approximately 58%, when the biodiesel fuel was used. IntroductionDiesel exhaust consists of noxious gases and diesel particulate matter (DPM). Recent attention has focussed on the potential carcinogenicity of DPM and the potential health impact on miners. The National Institute for Occupational Safety and Health (NIOSH) recommended that whole diesel exhaust be regarded as a “potential occupational carcinogen”, and that reductions in workplace exposure would reduce cancer risks (NIOSH, 1988). The International Agency for Research on Cancer (IARC) declared that “diesel engine exhaust is probably carcinogenic to humans” (IARC, 1989)."

Jan 1, 1997

By W. Torres Pino, L. Mariscal Samaniego

The Ilo Smelter has been continuously operating since 1960 with Reverberatory furnaces and Pierce Smith converters producing blister copper. The original installed capacity of 1.134 tons per day of concentrated was expanded in 1976. A process of modernization started in 1995 and 1998 with the installation of an El Teniente Converter, a sulfuric acid plant and an oxygen plant to reduce the gaseous emissions to the atmosphere. With the official approval of the Environmental Compliance and Management Program (Programa de Adecuaci6n y Manejo Ambiental - PAMA) in January 1997, Southern Peru Copper Corporation made a commitment to capture 91. 7% of the S02 generated at the smelter by January 2007. After an evaluation of six different technologies, the ISASMEL T process was selected because it can be easily adapted to the present operation, has a lower capital cost and it is a simple process. The fast learning curve to reach the total capacity will allow to fulfill the PAMA commitment in time. The project construction is in process and SPCC is prepared for a successful start-up and transition of the current operations at the end of year 2006. This paper outlines the factors considered by SPCC in its choice of ISASMEL T technology and describes the construction and the start-up activities of the new facilities.

Jan 1, 2007

By CH. Liu, H. X. Jiang, X. Xiao

"A study has been conducted to characterize the fatigue life in 7050-T7451 thick plate by the comparison between an experimental alloy and commercial alloy. The fracture origins were specified and their sizes were measured by scanning electron microscope (SEM). Additionally, the size, number density and spatial distribution of porosity in the experimental material and commercial material were characterized and compared, using X-ray Computed Tomography(XCT). The results showed that microporosity was the predominant site for crack nucleation and subsequent failure of the experimental alloy. However, as for the commercial alloy, fatigue cracks were found to originate from constituent particles. The presence of microporosity in 7050-T7451 thick plate reduced fatigue life of an order of magnitude or more compared to the commercial alloy. The relationships between size of origin and fatigue life were proposed. It was showed that the fatigue endurance was reduced when the size of porosity increased.INTRODUCTION 7xxx series aluminum alloys, due to their combination of high strength, high resistance to stress corrosion cracking, and good fracture toughness, are widely used in structural engineering applications where high-strength and low-density characteristics are fundamental design requirements (Williams& Starke, 2003). Every designer is striving to find an optimal combination of properties including strength, corrosion resistance and fatigue resistance (Wanget al., 2016). Based on the design principles of aircraft, a higher fatigue resistance of aluminum alloys are required. Thus, many investigations have been carried out on the microstructures and its effect on fatigue properties of the 7xxx series aluminum alloy (Robson, 2004; Schubbe, 2009).Microporosity, which is a common defect in casting materials, can lead to a significant deterioration of mechanical performance and fatigue resistance, especially in the high alloyed 7xxx aluminum alloys. The actual valid loading area decreases due to microporosity, which results in detrimental effect on the mechanical properties. Many experimental studies have been conducted in this research field. Mayer et al.(2003) investigated the fatigue properties of magnesium alloys produced by high-pressure die-casting. The results show that porosity in magnesium alloys greater than0.18mm diameter may be considered as the most important material defect for high cycle fatigue and fully reversed loading conditions. Nadot et al.(2004) found that the near surface defects are much more dangerous than the internal defects. Wang et al.(2001a) used the Weibull statistics method to analysis the influence of the microporosity, oxides and particles on the A356-T6 alloy fatigue life. The results show that, the porosity is more detrimental to fatigue life than oxide films and particles. With regard to fatigue resistance, although the deleterious effect of microporosity has been generally acknowledged, a quantitative understanding between casting microporosity and fatigue life in 7050-T7451 plate is not well established."

Jan 1, 2018

By Bai-ru Xia, Cang-qin Jia, Qi-wu Huang

Limit Analysis Theorems has revealed to be a powerful tool for the development of numerical models aiming the determination of the load bearing capacity of structures reached by plastic collapse. This work presents a numerical formulation for the computation of strict upper bounds of the collapse loads of rigid-perfectly plastic mechanical systems, derived within the kinematical theorem framework. A key advance of this present method is that the problem is described only in terms of nodes and discontinuities connecting those nodes rather than element or bodies. The alternative approximation procedure to the traditional finite element method might involve discretization of a given body using a suitably large number of nodes laid out on a grid, with the failure mechanism comprising the most critical subset of potential discontinuities interconnecting these nodes. Potential discontinuities which interlink nodes laid out across the problem domain are permitted to crossover one another, giving a much wider search space than when such discontinuities are located only at the edges of finite elements of fixed topology. Highly efficient interior point method solvers can be employed when certain popular failure criteria are specified (e.g. Mohr-Coulomb). By adopting this processing approach it is possible to solve very large problems which normally exceed the memory capacities of a single computer. The developed numerical tool reveals to be robust and versatile, able to solve a wide range of 2D problems. Velocity singularities are automatically identified and visual interpretation of the output is straightforward. Several numerical examples including rock slope are studied by the new method, and the results are very close to those calculated by using analytical method and FEM.

Jan 1, 2015

By George Delorme

"AbstractThe basic intention of this paper is to present, from a practical viewpoint, a thorough outline of all the sound and accepted principles connected with attaining satisfactory rope performance from multi-rope friction winders.In order to emphasize the importance of some aspects of rope maintenance, a limited amount of hoist rope theory has been included, a s it is felt that without this, some of the more critical, but nevertheless practical, aspects would perhaps pass without full appreciation of their individual merit.It is very much appreciated that many of the maintenance topics and practices discussed herein are already being observed with a high degree of skill among those already involved in modern friction winding. The hope is expressed, however, that the paper will be of additional assistance, and of particular help in introducing sound maintenance principles to those who are moving into this field of operation for the first time.Hoist RopesWITH a multi-rope friction winder system, structural upset within the hoist rope's cross section can occur if the ropes slip in the drum treads. This upset will usually appear at either end of the rope at the tangent point of the drum or deflection sheave with the respective conveyance in the normal uppermost position. This slipping action on the drum causes the outer cover of a Full Locked Coil or the strands of a stranded rope to shift, leading to structural upset. The result very often means that the ropes have to be withdrawn from service before completing their maximum service potential.The cause of any rope slipping in its tread can be associated with a discrepancy in tension of that rope between one side of the drum and the other."

Jan 1, 1977

By Sylvie Lévesque, Frederic Couët, Laura Pérez-Barnuevo, Cory Hennessey

Determining mineralogical characteristics of samples throughout the iron ore concentration process – from drill core samples up to the concentrate – is critical to process improvement and remediation. However, assessment of mineral proportions, liberation, and texture, although essential, can be time-consuming and costly. Thus, a mineralogical study is often not performed or only restricted to a limited number of samples. New iron ore deposits or new ore zones in active mines will bring new challenges as they are known to be problematic due to their lower grades, complex textures and presence of mineral impurities. In those cases, applied process mineralogy will be necessary to understand and to diagnose potential processing issues. To take full advantage of mineralogical information along the iron ore concentration process, new tools are being developed to provide mineralogical data based on texture, composition and liberation. In an early stage at the mine, the automated identification of drill core textures could provide essential information for the prediction of ore concentrability and grindability. In a later stage, the automated modal tool, combining the knowledge of the iron ore mineralogy of a specific deposit and the results of chemical analyses, can quantify the mineral proportions of the ore; results show good agreement between mineral estimation via chemical analysis and modal analysis using a Mineral Liberation Analyser. A bulk mineralogical analyser allowing semi-quantitative evaluation of the liberation of iron oxides is being validated. The results from the bulk mineralogical analyser will eventually be linked with the mineral proportions issued by the automated modal tool to provide complete mineralogical characteristics of iron ore samples. Ultimately, these mineralogical tools could provide valuable and timely insight for predicting concentrators’ performances or troubleshooting gravity separation processes.

Jan 1, 2016

By Brian W. Mackenkzie, Jozef Lajzerowicz

This paper is intended to familiarize planners in the noncommunist world with the district planning approach used in eastern Europe for mining development. It deals generally with the basic nature of the district planning problem, the planning process for mining development and the state organization for the planning of mining districts. A number of applications of district planning techniques to both established and new eastern European mining districts are described.

Jan 1, 1971

By Henrik Saxén, Mikko Helle, Hamid Ghanbari

In this study, a process integration approach in a primary steelmaking is investigated to evaluate future operation concepts of a steelmaking site considering sustainability issues. Mathematical programming is used to study the integration of the steel plant with chemical units for utilization of available off-gases in the system, and carbon capturing and sequestration unit. Different industrial carbon utilization options are considered to find the best route of development. A multi-period optimization model is developed based on site-wide mass and energy balances by considering the availability of the fuels and by-product gases and their consumption in the production system and a conceptual polygeneration system. The objective is to reach maximum economic profit while environmental aspects of integrated system are considered for different fuel systems, alternative blast furnace reductants and implementation of new process technologies. The model can provide useful information concerning techno-environmental and economic aspects for decision-making and can estimate optimal operational condition of current and future primary steelmaking under alternative scenarios. The results of the work illustrate the potential to develop steelmaking towards more sustainable operation in the future.

Jan 1, 2015

By J. W. Reynolds

Introduction The Sullivan mine, at Kimberley, B.C., is the principal source of ore for the Consolidated Mining and Smelting Company of Canada, Limited. Current production amounts to about 2,500,000 tons of lead-zinc ore a year. With approximately 1,600,000 feet of percussion drilling and 700,000 feet of diamond drilling being carried on each year, any improvements in drilling practice are important. Testing of new equipment and drill bits is a major function of the Testing Department at the mine. Tungsten carbide bits have been the subject of many tests since 1947 and have been used in operations since 1948. This paper details with the methods of testing and gives comparative data on performance and costs for tungsten carbide bits as compared to steel bits. Operational use of tungsten carbide bits started in April, 1948, and the extent of application has increased considerably since that time. The scale of employment is illustrated in Table I, which also shows other statistics on the use of carbide bits. Up to the present time eighteen types of carbide bits or tipped steel, as made by six different manufacturers, have been tested. In general, one supplier's bits have been used in operations, but some large-scale operational tests have been carried out with other types. The types tried are shown in Table II. To date they have been, the subject of 33 tests, covering the destruction of 804 bits over an observed footage of 42,586 feet.

Jan 1, 1951

Building off the enthusiasm generated by Credit Suisse First Boston on the potential benefits of an industry-wide effort to market gold jewellery, a group of gold producers, led by Randall Oliphant, CEO of Barrick Gold, decides to investigate the long -term impact of launching a significant marketing initiative to stimulate demand for gold jewellery. The group establishes an international Steering Committee representing producers of differing sizes, members and non-members of the World Gold Council. This Committee comprises representatives from AngloGold, Barrick, Gympie Gold, Kinross, Randgold, and Sons of Gwalia and is supported by the Australian Gold Council, the Gold and Silver Institute, and CSFB. The Steering Committee hires McKinsey to assist it by conducting an independent review of whether investment in a large-scale marketing initiative for gold jewellery would be effective in increasing demand for gold, and ultimately of significant economic benefit of the gold industry. Based on McKinsey?s review* and its own discussions with key stakeholders across the industry, the Steering Committee strongly believes the case for marketing is compelling and sufficiently proven to persuade the industry to undertake a major initiative over the next few years. The Steering Committee, supported by McKinsey, conducts briefings with a range of gold producers to share its findings and to understand producers? perspectives on an industry-funded marketing campaign. The Steering Committee is asking for your support to bring this industry-funded marketing campaign to life.

May 1, 2002

By G. Clarkson, M. Hitch, R. Clarkson

"A novel reagent-free method of extracting gold from gravity middling concentrates in the Yukon placer fields is presented in this paper. This method exploits the malleability of gold by submitting concentrates to grinding in a rod mill. Brittle waste minerals are effectively reduced, whereas malleable gold particles are flattened and are then extracted by classification through sieves. Recoveries in the field using a laboratory-sized rod mill regularly exceeded 90%, whereas correlation laboratory tests indicated recovery to be most sensitive to the mill charge size. This method has broad potential, including application to the gravity circuits of large hard-rock processing circuits.RÉSUMÉ Cet article présente une nouvelle méthode sans agents réactifs d’extraction de l’or dans les concentrés gravimétriques mixtes que l’on trouve dans les districts placériens du Yukon. Cette méthode exploite la malléabilité de l’or en broyant des concentrés dans un broyeur à barres. Les déchets miniers cassants sont bien réduits, alors que les particules d’or malléables sont écrasées puis extraites par classification au travers de cribles. Si les récupérations sur le site à l’aide d’un broyeur à barres de laboratoire excèdent 90 %, les essais de concordance en laboratoire indiquent que la récupération est très sensible à la taille de la charge du broyeur. Cette méthode présente un grand potentiel, notamment une application possible aux circuits gravimétriques des grands circuits de traitement des roches dures.INTRODUCTIONExploiting the high density of gold to separate it from waste materials is the oldest known mineral processing technique. This basic technique is still widely used in gravity concentration circuits today; however, gravity processing invariably results in high-value middlings, especially in the Yukon placer gold fields. In addition to having a uniquely high density, gold is also the most malleable metal. This unique malleability can be exploited to extract gold from otherwise inaccessible gravity middlings.The Yukon placer gold industry has been continuously ongoing since the 1860s, and today produces approximately 60,000 oz t (1.87 million grams) of crude gold annually, most of which is from the Klondike region near Dawson City (Van Loon & Bond, 2014). It is important to note that Yukon placer miners do not use any chemical extraction methods; rather, gravity upgrading methods are the sole processing techniques used. Placer deposits are typically coarse, well liberated, and naturally gravity concentrated and recoverable, thus making more expensive chemical extraction unnecessary (Mitchell, Evans, & Styles, 1997). Furthermore, a strict permitting regime, environmental concerns, lack of expertise, and fear of repercussions from regulators prevent miners from attempting more advanced processing methods, such as flotation or cyanidation. Even simple chemical extractions like mercury amalgamation have not been implemented for decades, with one observer noting that, as many as 30 years ago, “the art of mercury for amalgamating appear[ed] to be dying [in the Yukon]” (Osler, 1983)."

Jan 1, 2017

By E. E. Mason

THE Myrtle group of mining claims is situated on Barkerville mountain in the Cariboo mining district of British Columbia, west of the old mining town of Barkerville. An 1,800-foot adit, known as the Shamrock tunnel, was driven in 1935-36 from the Barkerville road and in the general direction of the Myrtle group. It was proposed to enlarge this adit to more convenient section, extend it 2,500 feet int0 Myrtle ground, and from there drive a main entry 3,000 feet along the length of the group. Several laterals were also to be driven off this main entry as part of the tunnel schedule. It was thus originally proposed to drive 5,500 feet of new adit and 1,800 feet of laterals, a total of 7,300 feet of new work. Work was commenced with a bulldozer on April 21st, 1941, cutting a bench on the hillside for a plant site. The power plant was ready for operation on August 8th. Slashing and re-timbering of the old adit rook longer than was expected. It was found that 57 per cent of the length required timbering, chiefly by fore-poling, and there was also trouble in several sections with swelling ground. First round in the new face was taken on September 17th, when a 2-shift daily schedule was commenced. Due to delays in delivery of electrical equipment, it was not possible to add the third shift until November 14th. From then on, a 3-shift daily schedule was maintained with the exception of holidays and fortnightly change Sundays until August 1st, 1942, when shortage of labour caused the dropping of a shift. All work was suspended on August 14th. The ground through which the tunnel passed was such that the driving was often interrupted by the need of protective timber at the face. Further, crews were continuously employed timbering behind the face, and in maintenance of timbered sections in swelling ground. Roughly 980 feet of the new workings are now timbered, about 21 per cent of the total.

Jan 1, 1942

By I. Masters, K. Buban, M. Faris, M. Antonio, M. Collins

"AngloGold Ashanti Brasil, with assistance from Sherritt International Corporation, has recently commissioned a new autoclave for the pressure oxidation of refractory gold feeds at their Corrego do Sítio operation in Brazil. Design of the new plant, including feed acidulation, pressure oxidation, oxidized solids washing and solution neutralization circuits, was based on the results of test work conducted by Sherritt at their pilot plant in Fort Saskatchewan, Alberta. This paper describes the results of the pilot plant study as well as highlights of the design exercise.INTRODUCTIONAngloGold Ashanti Brasil (AGA Brasil) has recently commissioned a refractory gold pressure oxidation plant at the site of the original São Bento operation in Brazil. The design of the São Bento pressure oxidation facility was based on Sherritt technology; Sherritt carried out the original process development test work in the mid-1980s, provided a process design package and detailed specifications for critical pressure oxidation equipment and participated in the training of operators and commissioning of the plant. The São Bento plant was operated between 1986 and 2007, when the original ore body was exhausted (Silva et al., 2004). AGA Brasil purchased the facility from Eldorado Gold in 2008, with the intent of refurbishing the plant to process refractory gold concentrates produced from the nearby Córrego do Sítio mining area.Sherritt International Corporation has a long history in the development and application of commercial pressure oxidation and pressure leaching processes. Sherritt’s development of technology for the pressure oxidation of refractory gold ores and concentrates commenced in the 1980s in collaboration with Homestake for application at the McLaughlin project in California. This was followed by several commercial applications in Canada, Papua New Guinea and Brazil (Berezowsky et al., 1991). More than thirty pilot plant campaigns investigating the pressure oxidation of refractory gold ores or concentrates have been conducted by Sherritt since the 1980s, and projects with Sherritt contributions to the process development studies and/or engineering design account for about half of the commercial plants that have operated to date with this type of process (Collins et al., 2011a; 2011b)."

Jan 1, 2012

By Chris Twigge-Molecey, John Peacey

To meet the business objectives of a metallurgical project, there is often a need for new and untried technology or equipment, whose very novelty can present serious risks to meeting those objectives. The key risk management approach is a rigorous stepwise progression from theoretical evaluations and laboratory tests to pilot plant trials. These must be followed by demonstration-scale trials before final construction of a commercial scale plant, paying particular attention to the magnitude of the scale-up between phases. Success depends on following a well-defined program, not eliminating any steps, and ensuring adequate resources are available to the development team. Chapter 6 discusses the nature of technology risks to metallurgical plant projects, and the rigorous management practices needed to identify, analyze, evaluate, and avoid or mitigate them.

Jan 1, 2015

By M. R. Campbell

"IntroductionON THE LAST DAY of December, 1951, a half-century of steel production was completed in the open hearth department of Dominion Iron & Steel, Limited, in Sydney, Nova Scotia.During that period, almost every known variation of basic steel making practice was used in working out a steel making process which would overcome the difficult metallurgical problems imposed by the use of Cape Breton coal and Wabana ore.This paper is presented as a brief review of these steel making practices, setting forth the fundamental metallurgical factors involved in their success or failure.Establishing the IndustryThe story of steel production at Sydney is closely interwoven with that of coal. The steel industry owes its inception to a desire on the part of the Dominion Coal Company, which was incorporated in 1893, to improve its marketing position by increasing sales of slack coal and providing a year-round demand for its product. Accordingly, the Dominion Iron and Steel Company, Limited, was incorporated on March 30th, 1899, with Mr. H. M. Whitney -who was President of the Dominion Coal Company -as its first President. The new Company was given powers to manufacture and process iron and steel, and to mine all minerals, including coal.A strong inducement to the industry was the bounty offered by the Dominion Government for the production of both iron and steel."

Jan 1, 1952