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By P. West-Sells, B. Wassink, N. Fisher

Gold leaching from a commercial cyanide-amenable gold ore was studied at 25°C using sodium bisulfide-hydrogen sulfide solutions containing elemental sulfur. Gold extraction from the ore using 0.55 M NaSH, 4.1 atm (60 PSI) H2S, 1 g/L S8 and 26% solids by weight was about as good as the best extraction obtained by cyanidation. Maximum extraction was achieved in roughly 48 hours. Sulfur dissolves in the bisulfide solutions to form a mixture of polysulfides. Simple speciation calculations indicate that gold solubility as bisulfide complexes should be roughly ten times higher than in the absence of added zerovalent sulfur. The principal bisulfide complex is believed to be [Au(HS)2]-. Gold dissolution is favoured by increasing HS- concentration and by increasing H25 pressure. Polysulfide complexes of gold are also likely to be formed, and may contribute substantially to gold leaching. Two experiments using pure gold were also performed. Up to 100 mg/L gold was dissolved in 140 hours using 0.55 M NaSH, 1 g/L added elemental sulfur and 6.2 atm H2S.

Jan 1, 2005

By T. A. Grammatikopoulos, B. Vasily, A. H. Clark

"The St. Lawrence deposit is a large wollastonite skarn (ca. 9 Mt @ 41.3% wollastonite) adjoining the gabbroic-to-syenitic Leo Lake pluton in the granulite facies Frontenac Terrane of the Grenvillian Central Metasedimentary Belt. It occurs within a horseshoeshaped horizon of quartzite, open to the east. The skarn extends over 1.2 km2, and comprises wollastonite-dominant, wollastonite-clinopyroxene, and diverse quartz-feldspar-sulphide (-titanite) layers, interbanded with, and strongly folded within, the quartzite. As in the world-class wollastonite deposits of the Willsboro district, New York, no carbonate protolith is preserved, and calcite is a negligible constituent of the mineralized zones. Wollastonite development is nonetheless ascribed to metasomatism of a metacarbonate unit by magmatogene, silica-rich, CO2-poor (XCO2 < 0.05) fluids, at P = 350 MPa and ca. 560°C, or, alternatively, 550 MPa and ca. 630°C.Several high-grade zones, averaging >40% but locally exceeding 80%, of translucent, white, tabular wollastonite grains, with lengths of 0.2 cm to 5 cm, have been delimited by drilling. Preliminary beneficiation studies yield high aspect-ratio and high-purity (low Fe and Mn) concentrates.St. Lawrence compares favourably to other known prospects and operating wollastonite deposits: having good chemical and physical properties, low iron content, and high aspect ratios (>20:1). In addition, the deposit has a favourable size and location, and will benefit from a low Canadian dollar. Canada currently has no wollastonite production."

Jan 1, 2003

By R.P. Edwards, B.C. Flintoff

Froth flotation is one of the most widely used and effective processes for mineral benefication. First introduced in 1911, flotation technology has seen many developments over the past 80-plus years. Innovations in reagent chemistry, equipment design, process analysis and process control have given design and plant engineers a powerful set of "tools" for process optimization. However, it does not follow that all flotation systems are optimized. As Klimpel observes: "The problem with the industrial flotation process is that it is relatively easy to get reasonable results, and relatively difficult to get excellent results." Klimpel [1988] While reasonable was sufficient in the past. competitive forces will make excellent necessary in the future. Judging by the activities in many Canadian plants this transition is already underway.

Jan 1, 1995

By Robert B. Parsons

"Once all the hullabaloo about Finance Minister Wilson&apos;s April 27 budget died down (or was it an April 26 budget?), the pain of the budget papers began to sink in. Individuals and corporations will have to dig deeper and pay more taxes - and government will continue to dig deeper and spend more. The irony of the situation is that higher tax rates actually make flow-through shares more attractive as a tax-deferral investment - a bittersweet ""bravo"" for the mining industry.INTRODUCTIONFor the first time in Canadian history, a major budget address has taken two days to deliver. Of course, it&apos;s not a case of long-windedness, but rather a case of a hastily called press announcement on April 26 in response to a budget leak, followed by a formal budget speech on April 27.The general reaction of the business community to the budget was to the effect that the tax hikes are acceptable, but the government&apos;s failure to curb spending is less than acceptable. Mr. Wilson&apos;s reported response indicated that the government had never promised to cut spending, and that increased government spending would actually benefit the country. That age-old debate will doubtlessly continue for generations.In any event, three noteworthy components of the budget papers are:• Personal income tax rates increase effective July I, 1989;• A ""large corporations tax"" (in effect &apos;a corporate ""minimum tax"") is effective July I, 1989; and• Federal sales tax increases are effective from June 30, 1989, to be replaced by a national sales tax in 1991.A brief overview of these and other budget proposals follows."

Jan 1, 1989

By Guy Chevalier

The QCM Mount-Wright mine and concentrator complex produces about 14 M tonnes of iron concentrate annually. Approximately 9.5 M tonnes of this concentrate are used to produce iron ore pellets at four different silica grades: Three for blast furnace operations and one for direct reduction furnaces. The paper presents the scientific approach that led to the realization of two projects where the acquisition of new process equipment led to an improved pellet plant iron recovery, a better flexibility and to lower operating costs as well as to the production of fine iron ore concentrate from the Port-Cartier tailings pond. Typical 4.8 % SiO2 concentrate is processed to achieve required pellet silica content. This is obtained with the aid of hindered settlers or hydraulic classifiers, screens, whims and, lately, spirals. The increasing demand for low silica iron ore products resulted in a greater need for upgrading. The Pellet Plant upgrading capacity being limited, more and more iron units were lost. Base on test works results and economic evaluations, QCM engineers figured out a way to increase efficiently their upgrading plant capacity and go back in the pond gather what has been lost in recent years of operation.

May 1, 2007

By Pierre Gauthier

Is the hydrogen economy of the future just another fish story? Absolutely not! There have been many changes affecting the energy equation over the last 10 years and conditions have changed. In this presentation, we will examine the reasons why, in the very near future, hydrogen production and distribution will be increasingly visible on many industries? radar screens.

May 1, 2007

By B. Samanta

Abstract - Ore reserve estimation, based on sparse drill hole data, was conducted for a placer gold property in Nome, Alaska. A problem with sparse data is that random subdivision of the data into modelling and evaluation subsets (as is commonly done) becomes a problem, as random selection may result in biased/skewed subsets. Therefore, a technique that combined data segmentation with genetic algorithms (GA) was applied to divide the samples into three equivalent subsets: training, validation and testing. Data segmentation was done on the basis of the distribution of gold values. Neural network and a variety of kriging techniques were used to estimate gold grades. A multi-layer feed forward neural network along with "early/quick stop" training was used for neural network modelling. A comparative evaluation of kriging and neural network methods was then performed. The results revealed that neural network was generally superior to the kriging techniques for gold grade estimation in the Nome deposit.

Jan 1, 2002

By A. R. Miller, M. C. Bétournay, D. L. Barnes

"A number of successful proof-of-concept projects have been carried out to replace conventional power application, such as diesel and rechargeable batteries, in underground mine vehicles. This has led to the development and testing of the world’s first fuel cell production vehicle, a mine locomotive. A fuel cell loader is being built and tested.This paper provides an insight into other projects that are being carried out. Some are related to further underground applications, and some to further research, such as refueling options, power plant durability, and vehicle automation.Also outlined is an evaluation of the overall mining applications and advantages this technology can bring to underground mining, including the facilitation of automation and tele-remote operation."

Jan 1, 2003

By L. K. Daneshmend

"Competitive pressures dictate that the mining industry moves to larger mobile underground haulage equipment with more advanced equipment mechanization, higher levels of autonomous operation of machines, and longer periods between access by maintenance personnel. Since such new machines will of necessity be more complex than existing designs, machine reliability has become a key issue in progressing toward advanced mobile underground haulage equipment. Reliability and maintainability models of such equipment are practically non-existent in the literature. This paper addresses the issue of reliability and maintainability of mobile underground haulage equipment on two fronts: reliability modelling to enhance decision making for maintenance planning; and reliability simulation to enable evaluation of more rigorous production planning scenarios. A case study from a gold mine in the Chilean Andes is presented, for which reliability models of mobile underground haulage equipment, specifically load-hauldump vehicles and underground haul trucks, are developed, and a reliability-based simulation implemented. IntroductionMaintenance accounts for 20% to 35% of the overall operating budget for a typical underground operation, and hence represents the largest portion of the mine’s controllable operating costs (Cutifani et al., 1996; Campbell, 1997; Goddard, 1998). This, coupled with the fact that industry today is faced with an ever more complex and demanding marketplace, has led to an increasing interest in methods to reduce maintenance costs.Although significant effort has gone into developing effective maintenance strategies for industry in general, application of these to the"

Jan 1, 2003

By S. D. Botts, F. Cantuarias

"The Antamina project, owned by BHP Billiton Plc, Mitsubishi Corporation, Noranda Inc., and Teck Cominco Ltd., is a $2.3 billion copper/ zinc project, located in the Ancash Department of Peru. The project consists of an open pit mine, a 70 000 ton per day concentrator, a 302 km long concentrate pipeline, port facilities, a new access road, power line, and town site. The project is designed to produce up to 1.5 Mtpy of copper and zinc concentrates over a 23 year project life, and will be the third largest producer of zinc and the seventh largest producer of copper in the world.This mega project is the largest mining investment in the country and, during its construction stage, was the most important construction project worldwide. On May 28, 2001, Antamina commenced testing operations and four months later, it reached commercial production. Antamina was officially inaugurated on November 14, 2001 by Peruvian president Alejandro Toledo.The construction stage of the project generated 8000 direct jobs, with a peak of 10 000 employees, and 30 000 indirect jobs. The permanent workforce consists of approximately 1650 employees, the vast majority of which are Peruvian Nationals, around 30% of whom came from the region where the deposit is located. Approximately 5600 indirect jobs were generated from the project. Independent sources state that Antamina increased the Peruvian mining exports by 30% (mining exports constitute 50% of Peru’s total exports) and Peruvian GDP by 1% in its first year of full operation in 2002.Since winning the privatization bid for the project in 1996, the company has implemented an approach to community development and environmental protection based on sustainable development principals. Throughout the development of the project, a number of initiatives have been undertaken to ensure full involvement of the local populations in community development activities and the company’s environmental program.Due to its size, difficult logistics, cultural considerations and financial aspects, the project has faced a number of unique challenges in the area of environmental protection and management of community interaction. Antamina has been innovative in its approach to these issues and, as a result, has set new standards in Peru for environmental and community management and sustainable development."

Jan 1, 2003

By Arthur D. FitzGerald

EDC established an Environmental Review Framework in 1999. Throughout the early fall of 2001, the Corporation held public consultations across Canada to strengthen that framework, leading to a public release on November 15, 2001 of a report summarising the results of these consultations. Following this, the Corporation implemented strengthened environmental review requirements in the form of its Environmental Review Directive, in compliance with legislated amendments to Canada?s Export Development Act that went into effect on December 21, 2001. Over the past few years, there has been a global trend towards an increase in the social and environmental requirements of multilateral/bilateral financial institutions and export credit agencies. More recently, this activity has focussed on capturing institutions that have not yet adopted similar requirements and, more specifically, on developing a convergence of the requirements from institution to institution. This paper describes EDC?s new ERD and some of the initiatives that have taken place or are in process that are moving international financial institutions toward converging their environmental and social requirements for projects in the private sector.

May 1, 2002

By M. G. Lipsett

"The Mining Information Technology User Group considers information to be a strategic enabler to improved business performance in mining. This ad hoc group has been meeting since 2000 to share knowledge and leverage their efforts in effectively using IT in mining. In this paper, core issues to mining IT are reviewed, along with initiatives to engage industry professionals and decision-makers in the potential for improved use of information in their operations. Relevance of IT to Canadian MiningMining operations always drive to improve their performance, and so far they have succeeded by using different technologies. While economies of scale have come in fragmentation and material handling, and energy usage has improved through conservation and design of integrated mineral processing plants, these systems have the net result of tightening operational constraints, through reduced excess capacity. There are higher opportunity costs of lost production when integrated, large-scale systems are operating in a sub-optimal way.The problem is that it is profoundly difficult to run a mine in an optimal way. Optimization requires a defined objective function (e.g., profit), which is hard to pose, let alone solve, because so many inter-related aspects of an operation affect the bottom line. Even for a small, well-defined process state, it is difficult to measure all the pertinent information with sufficient accuracy to ensure that the system is performing well in real time.The art of mining remains making good decisions with uncertainty: in the orebody delineation; in the allocation of resources; in the efficiency of the operation; in the reliability of components and systems; and in responding to the downstream market. As well, individual decision-makers need to know how their decisions affect other processes and systems, so that improvements in one part of an operation do not result in such degraded performance in the rest of the plant that overall profitability goes down."

Jan 1, 2003

By P. L. Richard

An open pit a mine can be thought of as a business unit, with capital, operating and maintenance costs that exceed those of many large business enterprises. Truck-and-shovel operations have an inherent ?looseness? to them, unlike manufacturing or processing operations where production components are tightly coupled (through conveyors, material flow in pipes, assembly lines, and so on). Effective monitoring and control of truck-and-shovel operations requires a combination of both information systems and performance management. Production monitoring systems can impact operations at three levels: minute-by-minute decisions during the shift, procedures, and policies. The technology of production monitoring ranges from real-time data collection to manual entry of time card data into a computer. Time card information is too coarse to effectively manage a multi-million dollar fleet of mobile equipment, so a higher level of production monitoring is required. People issues affect whether the implementation will be a success or a disappointment. Considerations that affect the people issues are discussed, including common obstacles, and key success factors. A balanced scorecard approach must be used, since uni-dimensional measures of performance like tons produced give no indication of whether the production was achieved at the expense of another factor.

May 1, 2004

By P. L. Richard

An open pit a mine can be thought of as a business unit, with capital, operating and maintenance costs that exceed those of many large business enterprises. Truck-and-shovel operations have an inherent “looseness” to them, unlike manufacturing or processing operations where production components are tightly coupled (through conveyors, material flow in pipes, assembly lines, and so on). Effective monitoring and control of truck-and-shovel operations requires a combination of both information systems and performance management. Production monitoring systems can impact operations at three levels: minute-byminute decisions during the shift, procedures, and policies. The technology of production monitoring ranges from real-time data collection to manual entry of time card data into a computer. Time card information is too coarse to effectively manage a multi-million dollar fleet of mobile equipment, so a higher level of production monitoring is required. People issues affect whether the implementation will be a success or a disappointment. Considerations that affect the people issues are discussed, including common obstacles, and key success factors. A balanced scorecard approach must be used, since uni-dimensional measures of performance like tons produced give no indication of whether the production was achieved at the expense of another factor.

Jan 1, 2004

By J. S. Phipps, D. R. Skuse

"Aqueous slurries of fine particle size calcium carbonate are used in a diverse range of end-use products. In many cases, the end-use performance is governed by the fineness of the particle size distribution. In turn, the maximum fineness of the particle size distribution is primarily determined by the efficiency of the dispersants used during the production process. Here, we report the sodium polyacrylate mediated dispersion of calcite and kaolin. Firstly, we report a colloid chemical description of the dispersant behaviour and attribute the stabilization to both steric and electrostatic mechanisms. Secondly, we describe how the understanding developed in the first part of the study can be utilized to produce more effective dispersant systems which allow the preparation of added value, higher solids and finer particle size calcium carbonate slurry products. IntroductionConcentrated aqueous dispersions of fine particulate kaolin and calcium carbonate are used extensively in the coating of paper. Currently, more than 10 Mt of such dispersions are used annually in North America and Europe alone, and worldwide consumption is growing at around 3% per year.Generally, paper is coated to enhance its visual appearance. Firstly, coatings improve the optical properties of the blank sheet, i.e., its brightness (or whiteness), opacity and gloss. Secondly, they improve the physical properties of the sheet that will influence the quality of the final printed image, such as surface smoothness, porosity, and ink absorption. In order to achieve these aims economically, paper coatings must be applied at high speeds and with minimal drying costs.Kaolin and calcium carbonate pigments are the major components of most paper coating formulations. Particle size distributions are chosen to maximize the optical benefits that they confer, and to allow the production of formulations that can be easily pumped, handled and coated. Coating pigments are generally produced and transported as slurries, and so it is important to obtain dispersions with the highest possible solids content, both to minimize drying costs and the quantity of water transported. This paper examines the dispersant technology that is currently used in the industry and the mechanisms by which it functions, and illustrates ways in which this technology has developed and could be further improved in the future."

Jan 1, 2003

By Matthew P. Wickham

The use of existing mine records in conjunction with an appropriate classification scheme can be used successfully to identify and characterize the composition of existing waste rock facilities where traditional approaches based on sampling may be impractical or costly. This paper describes an alternative approach used in an acid rock drainage investigation at a porphyry copper mine with numerous waste rock dumps of varying ages and composition. The approach integrated detailed lithologic and mineralogic information about the ore body and overburden materials with records of pit development and dispatch. A waste rock characterization matrix was developed for the site to meaningfully classify lithology and mineralogic composition of the waste rock. The approach resulted in a focused geochemical testing program and facilitated interpretation and application of the test results.

May 1, 2002

By Kevin J. Palmer

The introduction of the National Instrument (?NI?) 43-101 Standards of Disclosure for Mineral Projects has led to some very specific requirements to reporting a Mineral Resource estimate for mineral projects to the public. There are elements of the Mineral Resource estimate that are based on the qualified person (?QP?) completing the work to accepted industry practices and applying their relevant experience. There is no document that defines what is considered the accepted industry practices. There are guidelines provided by the Canadian Institute of Mining, Metallurgy and Petroleum (?CIM?) but, in general, the industry practices are dynamic and often different QPs will estimate the same mineral project in different ways. This sometime happens on exploration projects as they proceed from one study to the next. The focus of this paper is to provide a review of some of the current practices that are published in Technical Reports (Preliminary Assessment to Feasibility studies) with respect to classifying a Mineral Resource as Inferred, Indicated and Measured and the grade interpolation and modeling methods, data support (i.e. geological drill hole spacing) and validation methods employed.

Oct 1, 2010

By X. S. Yuan

With the production increase of Oil Sand in Fort McMurray Alberta, more efficient tailings disposal has become a priority for Syncrude Canada Ltd. A lot of work on tailings research and development has been compiled to determine the most effective deposition to increase reclamation options, water re-use and thermal energy recovery. Efficient flocculation of fine oil sand tailings is the key technology for thickening. It was identified that flocculation of fine transition/marine ore tailings using a single flocculant was not effective. The thickener overflow contains 1-4% solids content compared with the target solids content of <0.5% obtained with Estuarine ore. As a result, novel processes for treatment of fine transition/marine ore tailings have been developed at Syncrude Bitumen Production Development since June 2004. While the conventional processes using a single flocculant, a single coagulation, or a coagulant-flocculant combination was ineffective for transition and marine ore tailings, the new processes including Coagulation-Flocculation-Coagulation (CFC), Flocculation-Coagulation (FC) and Flocculation-Coagulation-Flocculation (FCF) were acceptable options. The key components of these technologies consist of the recipe of chemicals and their adding sequence. With these technologies, almost all sub-micron clay minerals are aggregated together and settle as a whole, resulting in a clear supernatant of less than 0.1% solids.

Jan 1, 2006

By Clifford S. Gibson

THESE troubled times suggest three reasons for maximum effort to control silicosis: (1) To keep to a minimum the ever-increasing burden occasioned by past deficiencies in this respect. (2) To effect the greatest production with maximum efficiency, which means at the least cost. (3) To preserve man-power in every way. Good control of the silicosis problem aids these aims. Inadequate control hampers all three. Insofar as our knowledge goes, silicosis in Ontario mines is caused by the inhalation of finely particulate quartz. It follows, therefore, that removal of dust containing this mineral automatically erases the cause. The achievement of this ideal is the aim of the mine operator. His best tool to this end is ventilation. This paper discusses mine ventilation from the viewpoint of dust control and it is hoped that in so doing there may result a better understanding of the part played by air in silicosis prevention. No attempt will be made to treat the subject fully. Instead, there will be presented certain salient aspects culled from field observations, the data in all cases referring to gold mines, unless mention to the contrary is made.

Jan 1, 1942

By Oyku Selimoglu

The key to successful mine production plan and subsequent operation is efficient mine layout design and optimization. Pit layout design and optimization allow the delineation and extraction of mineable reserves and the minimum waste subject to slope stability, economic, quality and quantity constraints. Many design and optimization software packages have been developed to aid this intensive and challenging process. These packages include VULCAN, SURPAC, DATAMINE, GEMCOM, MICROLYNX, MEDSYSTEM and MINESIGHT. These software packages are developed as integrated computer-aided systems used for database creation, survey, geological and geostatistical modeling, mine planning and production optimization and environmental modeling. In Turkey, many mining companies still plan and design mine layouts with traditional hand methods. In this study, VULCAN has been used to design and optimize the Eti-Bor A.S. Kestelek Boran Open Pit Mine in Western Turkey. The main objective is to show the company the superior advantages of mine planning software for designing and optimizing mine layouts over the traditional hand methods. Drill hole data used by the company to estimate the reserves for planning are used in this study. The ore grade varies between %1,04 B2O3 to %47,33 B2O3. The pit toe and crest strings are projected using variable batter angles and berm distances. On the north side, batter angle is 180 and berm distance is 25 meters, on the south side, batter angle is 320 and berm distance is 15 meters. In addition to that open pit bench height is 10 meter. The concepts of block modeling are applied to the Kestelek open pit mine with detailed ore grade modeling for each block. The Lerchs-Grossmann?s algorithm is used to optimize this mine based on the block model, the economic block values for each block and the underlying field constraints. The results from VULCAN were similar to the estimates by hand. The reserve estimates from VULCAN is 13,192,870 tons compared with the hand estimate of 13,200,000 tons, overburden estimates of 15,622,889 m3 compared with 15,000,000m3 obtained by hand with a stripping ratio 1.18:1 (m3:ton) from VULCAN versus 1.14:1 (m3:ton) from hand estimate. Vulcan improves the efficiency, speed and reproducibility of the planning results. It provides mining engineers, geologists and surveyors with a cost-effective modular system for assessing and planning the mine layouts. Furthermore, Vulcan?s specific modules allow efficient access and manipulation of databases, open pit mine design, block models, optimized 3D mine layouts, and more. However, for competitive business in Eastern Europe, VULCAN should improve its software support. Effective training, help desk support systems and nearby distributors with just-in-time solutions to company problems will generate competitive business for VULCAN.

May 1, 2007