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By Klaus Tietz, Hamish Adam, John Selby, Ian Glazier, Brian Sinfield

"Room-temperature tunable diode laser (TDL) analyzers are gaining in acceptance for highly critical safety monitoring applications in a variety of industries. This paper describes the testing, evaluation and deployment of a laser-based hydrogen cyanide monitoring system at the Campbell Complex of Goldcorp’s Red Lake Gold Mines in Balmertown, Ontario, Canada.A trial, single channel installation was followed by a staged multi-channel installation. Unexpected technical issues with the multi-channel installation were addressed and resolved.INTRODUCTIONLaser-based gas detection has several advantages over existing gas detection techniques (Ballangrud, 1993; Silver, 1992; Bomse, 1995; Table 1). For practical purposes, lasers generate light at a single wavelength. Room temperature tunable diode lasers (TDL) emit light in the near infrared (NIR) part of the electro-magnetic spectrum. Many gases of interest, including HCN, NH3 and others, absorb energy in the near infrared (NIR). Each gas has a unique absorption signature, or spectrum, made up of a large number of individual “absorption lines”. A TDL can be tuned to select a single absorption line of a target gas, which does not overlap with absorption lines from any other gases. Therefore, laser gas sensing is selective and does not suffer from interference from other gases. The single-wavelength nature of laser light also means that laser gas analysers have a linear response over a wide dynamic range.Tunable Diode Lasers (TDL) generate only a few mW of power. However, all this power is concentrated at one wavelength, the wavelength where gas absorption occurs, resulting in high signal-to-noise ratios and short response times, typically of about 1 or 2 seconds (Ballangrud, 1993). This also means that long path lengths can be used, enabling accurate measurements of very low concentrations, even with weakly absorbing gases. Tunable Diode Lasers provide all the advantages of other semiconductor devices: they are small, solid-state devices, operate at room temperature, and have long-term reliability (over 15 years). Currently, they can be obtained for any wavelength throughout the NIR (700nm to 2000nm). Because many gases absorb in the NIR, the technique is widely applicable."

Jan 1, 2011

By William J. Purdy

Successful design, operation and completion of a surface waste management facility for a diamond mine located in Canada?s northern environment requires careful planning to minimize short and long term environmental impacts. As part of the mine development application process, best practice standards were applied using conventional engineering to reduce the environmental effects of the mine waste facility at the Snap Lake Diamond Project. This paper presents the design criteria, site conditions, material characteristics and engineering management objectives considered for optimization of the development plan. Insight into the engineering analyses, development alternatives, monitoring program and reclamation strategy plan to be undertaken during mine operations to provide opportunity for adaptive management and to minimize environmental impacts is provided.

May 1, 2004

By J. A. Caceres

Mining planning and mineral processing are almost two unconnected areas. The mining area builds its economical models considering the plant like a constant parameter: a constant throughput, an average recovery and a unitary cost. On the other hand, the mineral processing area assumes a mine plan with grades, ore type, work index, estimating the performances in an independent way. Previous researches have evaluated the advantage for increasing throughput by increasing the liberation size, thus sacrificing recovery. These valuables approaches have left behind the work index factor, critical variable for Recovery-Throughput capacity estimation. This study describes a method combining mineral processing and mining planning. This method incorporates the grinding and flotation performances into the mining economic models optimizing simultaneously the Throughput- Wi(Work index)- Recovery relations with mining sequence, cut-off strategies, and reserve schedules. This method has been used at Andina Mine Chile, showing 18% net present value increasing with minimum investment associated.

May 1, 2003

By Fidelis T. Suorineni

Rapid drifting enables quicker access to orebodies, higher production rates and a resultant reduction in production cost. The Mining Innovation, Rehabilitation and Applied Research Corporation (MIRARCO) funded by the Canadian Mining Industry Research Organization (CAMIRO) has developed a methodology for safe rapid drift development within the underground metalliferrous mining industry in Canada According to industry survey, about 36% of drift development cycle time is spent on support installation. MIRARCO has developed a methodology for safe rapid drift development based on minimizing time spent on support installation. The methodology includes a critical review of the rockmass classification systems, examination of current support practices in the mining industry and civil tunneling, review of rapid drift development practice in South Africa, introduction of risk hazard procedures to account for material property variability and the development of a WIZARD as a quick decision-making tool for the implementation of the procedures. A comprehensive field data collection procedure was put in place and data collected from various mines to verify and calibrate the support selection rationale. The findings of the research programme resulted in the development of an improved rockmass classification system and showed that construction effects have drastic influence on support levels but is often not accounted for in assessing support levels. Stress effects and structurally controlled failures are the other important factors to take into account in rapid drift development. Three support classes were established for safe rapid drift development as No Systematic Support, Light Support and Strong Support. The support levels took into account cost, rate of installation and safety based on compatibility with ground characteristics. This paper describes the methodology for safe rapid drifting within the underground metalliferrous mining industry in Canada and highlights the key issues and major drivers behind their continued development at the Geomechanics Research Centre within MIRARCO.

May 1, 2004

Experimental Mine, Val d'Or, Quebec, Experiments on the ignition of sulphide dust clouds by explosives have been conducted in a 1 m3 explosion chamber. The explosives tested are ANFO, emulsion, aluminized emulsion and Detasheet. By controlling the composition of the ANFO and the emulsion explosive the oxygen balance could be changed in order to identify the dominant factors in the ignition of sulphide dust clouds by explosives. Experimental results, combined with theoretical calculations, show that the temperature of the detonation products is the most important parameter in the ignition of the dust cloud while the combustible detonation products are of secondary importance in the case of non-aluminized mining explosives. In the case of aluminized explosives and explosives having very negative oxygen balance the ignition of the dust cloud is assisted by the large amount of combustible detonation products.

Jan 1, 1993

By Takahiro Kubo, Katsunori Yamaguchi, Hidehiro Sekimoto

Equilibrium relation between B2O3 slag, RExOy-B2O3 (RE = rare earths) slag and Fe-C alloy formed by melting treatment of neodymium magnet and B2O3 was investigated. When neodymium magnet was melted together with B2O3 and Fe-C alloy in carbon crucible, 3 liquid phases of B2O3 slag, RExOy-B2O3 slag and molten Fe-C alloy formed and clearly separated by the difference of the specific gravities. In the case that excess amount of Cu was also introduced in that system, molten Cu phase additionally formed. Almost all amount of RE were concentrated in RExOy-B2O3 slag. The concentration of RE in RExOy-B2O3 slag increased with the decrease of the melting temperature. While chromium, phosphorous, nickel, cobalt, and copper were concentrated in molten Fe-C alloy, silicon and aluminum were distributed in B2O3 slag and RE2O3-B2O3 slag.

Jan 1, 2014

By S. R. Gilbert, C. O. Bounds, R. R. Ice

"Many ores are upgraded to produce auriferous sulphide concentrates (principally pyrite) which are not amenable to direct cyanidation. Often these refractory gold-bearing concentrates contain undesirable elements such as arsenic, antimony, etc., which present environmental and/or processing problems. The pretreatment techniques most often considered for processing these concentrates prior to cyanidation include roasting, pressure oxidation, chemical oxidation, pre-aeration, and recently, bacterial oxidation. In this paper, the technical performance and economics of bacterial pre-oxidation vs the classical roasting approach for treating a specific auriferous pyrite concentrate are compared. The results provide flow sheets, preliminary operating and capital cost estimates, and rates of return for the two processes and demonstrate the potential advantages of bacterial pre-oxidation. IntroductionThe increased attention that gold has received in the last ten years has prompted mining companies to look for lower grade orebodies. Many of these low-grade ores do not respond well to conventional direct cyanidation recovery techniques. As free-milling ores decline, gold is sought in refractory environments which, ultimately, drive up the treatment costs.There are a number of reasons for a gold ore to be termed refractory, most of which can be identified by thorough mineralogical examination. The mineralogical occurrence of gold can, to a great extent, impact the method by which the ore is treated and, consequently, the capital and operating costs. Gold in a refractory ore can often occur as discrete particles locked in a host of silicate or carbonate gangue, or associated with sulphides or sulphosalts. Depending on its particle size, gold can be liberated and recovered by mechanical size reduction such as regrinding. This approach is most effective for gold in the 10 - 50 micron range. Gold can also be associated with clay, iron hydroxides, or other minerals which tend to coat the gold surface and inhibit the penetration of the cyanide solution, resulting in poor plant recovery. Because of their resistance to cyanide dissolution, gold tellurides and other refractory gold minerals are also responsible for losses to the tailings. For these reasons, it is paramount that the mineralogical occurrence of the gold be thoroughly and accurately determined before selecting a final process flowsheet."

Jan 1, 1988

By J. P. Sancho, L. F. Verdeja, J. I. Verdeja

"This paper analyzes the present state of the different processes competing to keep their market shares within the future iron and steel business sector.The continuous transformations in the steel making process are also studied here. These transformations have happened especially during the two last decades obviously favouring steel price, properties, quality and environmental compatibility in the new millennium. IntroductionIn the early 1980s, world steel production reached a historic figure; specifically in 1982, the amount was 645 Mt (Verdeja et al., 1993). This might have been one of the reasons why the United States, Japan and the European Community drew up a declaration of principles after which the leading industries and sectors in the following century’s development would be: advanced materials, also known by the very diffuse term of new materials; information technologies; and biotechnology (Eager, 1998).On the threshold of the 21st century, it can be inferred that information technologies (computers and telecommunications) have progressed spectacularly. Nevertheless, there have been downsides too; technology develops so quickly that after a few months the products are obsolete. Environmental problems may also appear in a few years due to storing so many useless devices. At the same time, the achievements of biotechnology did not meet the optimistic forecasts made in the early 1980s.On the other hand, it is also curious that some solutions for the environmental problems generated by star technologies of the new millennium, such as computers and biotechnology, are closely linked to the iron and steel industry. For example, blast furnaces in Germany and Japan are prepared for burning residua by introducing polymer materials from computers and other electronic prepared devices through their tuyeres, while cement tube furnaces can destroy any organic residua from different origins."

Jan 1, 2002

By M. P. Amsden

"Ecstall Mining Limited, a subsidiary of Texas Gulf Incorporated operates the Kidd Creek Mine, a 10,000 tons per day base metal producer, near Timmins, Ontario. Two different ore types are mined and milled: copper-zinc and silver-lead-zinc. At the highly automated Ecstall Concentrator the ores are processed by selective flotation in threes individual circuits. One of the most important metallurgical tools for process control is a sample system incorporating continuous on-stream x-ray analysis. Recently this system was further automated by adding computer control of reagents for two copper-zinc flotation circuits. The computer programs, utilizing optimum seeking methods and smelter contract terms, have increased copper recovery 0.8%, zinc recovery 1.6%, and reduced reagent costs by 12%. Although not anticipated, copper and zinc concentrate grades were improved modestly as well.INTRODUCTIONSEcstall Mining Limited, a wholly owned subsidiary of the Texas Gulf Incorporated operates the Kidd Creek Mine, one of the world's major base metal producers, near the old gold mining centre of Timmins, Ontario. Discovered in 1964, the property was brought into production in November, 1966. Originally designed for 9,000 tons per day, the operation now treats 10,000 tons per day of two different ore types mined from a single open pit. In the near future, open pit ore will be supplemented by ore from an underground operation now being readied for productionAt the Ecstall Concentrator the ores are processed by selective flotation in three individual circuits. The whole plant is highly automated and control is coordinated from a central control room. The treatment process follows conventional practices although fine grinding is required for optimum flotation recoveries. Normally, two circuits treat copper-zinc ore at a combined rate of 6,500 tons per day while the third circuit treats 3,500 tons per day of silver-lead-zinc ore. Special production averages 2,400 tons per day."

Jan 1, 1973

By F. Hassani

This Paper describes a sudden spill of rock waste used for backfilling from a waste pass at one of the underground mine in Canada thus causing a major failure/accident. The mine operator immediately launched a detailed investigation to understand the causes of this accident and develop procedures to prevent any recurrence of such events in future. The investigators from McGill University were invited to collaborate with the engineers at the mine to examine this accident. The events leading to the accident were studied and appropriate measurements were taken and samples of the waste material was collected for further test and analysis. The field visit and the interview of the witnesses allowed a detail documentation of the events. The sequences of events related to the incident together with the experimental results obtained in the course of the investigation is detailed. The waste material was characterised in the laboratory with regard to its behaviour in the presence of water. This information is then discussed and the failure mechanism involved in this accident is identified. The full recommendation as well as the immediate operational measures implemented by the mine to prevent future occurrence of such events are discussed and presented.

May 1, 2003

By Graham Davey

"Ultrafine grinding of minerals has been in wide spread use in the industrial mineral field for over 30 years. Within the last 10 years the metalliferous industry has shown interest in the ability to produce ultrafine particles, as chemical, physio-chemical and physical separation processes have advanced to be able to treat ultrafine metalliferous particles. Also as the primary mineral deposits are depleted, new more difficult deposits must be mined. Existing operations are also looking to maximize economic return from existing deposits, requiring new thinking and technologies.The recent development of industrially proven and cost efficient technologies for ultrafine grinding has opened up another processing option for the treatment of finegrained metalliferous and refractory gold ores. The current commercial designs are variations of stirred mills used in the industrial minerals sector for the past 30 years. For the purposes of this paper ultrafine grinding is considered to be P80 of less than 15 microns.Attrition milling to fine grind sizes presents some challenging issues relating to scale-up including the dearth of information on the quantitative impact of feed and operating conditions, as well as the precise and accurate measurement of particle size distributions. Two examples from recent installations will be analyzed including Thalanga Copper and Century Zinc Mines. Both have diverse grind size targets for the SMD, yet both have realized significant metallurgical gains."

Jan 1, 2002

By G. I. Mathieu, R. W. Bruce

Flotation schemes for the separation of molybdenite from other minerals are based on utilizing the Inherent hydrophobicity of molygdenite (Fuerstenau1). This natural floatability was attributed to the crystalline structure of molybdenite by Gaudin et al.2 who suggested that any surface formed by the rupture of van der Wall's bonds should be hydrophobic and, therefore, naturally floatable. Other authors argued that "natural floatability" is dependent of adsorption of hydrocarbon ions and/or molecu1es on the surface of the minerals. This theory, albeit-c questioned 1,2 has long been recognized in actual practice of molybdenite flotation as the latter in carried out with hydrocarbons, such as fuel oil, kerosene and stove oil. Although conferring ready floatability to molybdenite, these presents generally have little effect on other sulphides and silicates. However, talc is a noteworthy exception because of its innate floatability4. Not withstanding the reason for this behavior which has also been attributed to crystal structure2 its end results as in the case of molybdenite is an immediate flotation response to frothing oils arid kerosene, as was observed by Baranovski5, Sutherland and Wark6.

Jan 1, 1974

By M. W. Lewis

A mine's inherent capacity is dictated by factors such as equipment, design, people, processes, and environment. Actual production may approach, but never surpass, the inherent capacity limit. The inherent capacity ceiling can only be increased through re-engineering. Autonomous haulage systems have the potential to significantly increase a mine ’s inherent and realized capacity. Realized capacity may be maximized through the optimization of soft factors such as the processes, behaviours, and organizational systems, controlling asset utilization, availability, and performance. Truck shovel dispatching systems revolutionized the utilization of mobile assets. High-precision global positioning systems (HP-GPS) are increasingly being adopted to optimize equipment performance. Real-time maintenance management systems have the potential to revolutionize equipment availability and significantly reduce cash costs. This paper explores some of the solutions available to mines to increase their inherent capacity and maximize their realized capacity.

Jan 1, 2004

By M. W. Lewis, B. Sambirsky, J. Werner

A mine’s inherent capacity is dictated by factors such as equipment, design, people, processes, and environment. Actual production may approach, but never surpass, the inherent capacity limit. The inherent capacity ceiling can only be increased through re-engineering. Autonomous haulage systems have the potential to significantly increase a mine’s inherent and realized capacity. Realized capacity may be maximized through the optimization of soft factors such as the processes, behaviours, and organizational systems, controlling asset utilization, availability, and performance. Truck shovel dispatching systems revolutionized the utilization of mobile assets. High-precision global positioning systems (HP-GPS) are increasingly being adopted to optimize equipment performance. Real-time maintenance management systems have the potential to revolutionize equipment availability and significantly reduce cash costs. This paper explores some of the solutions available to mines to increase their inherent capacity and maximize their realized capacity.

Jan 1, 2004

By Ray Walton, Ron Colquhoun, Ken Thomas, Dwayne Fentie, Barney Burke

"The new Roasting Facility at Barrick’s Goldstrike Mine in Nevada, U.S.A. was developed to process 12,000 tons per day of refractory gold ore. The process consists of crushing, dry grinding, roasting, extensive gas purification, calcine quenching and leaching in the presence of activated carbon. The new plant is integrated into the existing Goldstrike facility, treating ore from both open pit and underground sources.The process design, procurement, construction and commissioning of the Roaster facility was performed successfully over a 3% year period with peaks of 400 engineering personnel and 950 construction personnel supporting the project. The US$330,000,000 project was completed ahead of schedule and under budget. The commissioning was well planned and proceeded smoothly through a rapid start-up to achieve all primary goals within three months of the start of processing of ore.BACKGROUNDAs early as 1992, Barrick’s Goldstrike Mine, located north of Carlin, Nevada had indications of the ore becoming ever increasingly carbonaceous in nature. As the open pit and underground exploration programs proceeded to step out over the years that followed, the accumulative amount of carbonaceous refractory ore and tons had become significant. By 1997, 29 million tons of double refractory carbonaceous ore containing an estimated 11.6 million ounces of gold had been identified. By 2000 the resource had increased to 14.3 million ounces."

Jan 1, 2001

By Zhuo Chen, Jun Zhou, Jiemin Zhou

Samples of the reacting suspension particles were taken from the reaction shaft of a commercial flash furnace at different heights. The processes of matte and slag formation and morphology of the samples in the shaft were observed and analyzed. Variations of matte and slag composition in the shaft were investigated. By analyzing the samples taken from the settler at different locations, settler processes were studied such as slag formation, agglomeration and separation of matte-slag phases, Fe3O4 reduction, copper-in-slag reduction etc. In accordance with the characteristic of matte and slag formation the flash furnace can be divided into 6 functional regions, and a mechanism model called as “Micro bath process” is proposed for matte and slag formation in a commercial flash furnace. INTRODUCTION During flash smelting, concentrate particles scattered in the reaction shaft complete their oxidation reactions in suspension. The droplets produced fall into the settler beneath with a small amount of un-melted solid particles, agglomerate and separate into matte and slag layers which are tapped out from their tap holes separately. With respect to the extent of slagging reaction in the reaction shaft, there isn’t any commonly accepted understanding in literature (Kimura, Ojima, Mori & Ishii, 1986; Kemori & Kondo et al.,1988; Kemori, Denholm & Kurokawa, 1989; Fagerlund &Jalkanen, 2000). Some assume that the slagging reaction in the shaft can be ignored and some propose that all slag is produced in the shaft. With regards to the characteristics of the physical-chemical changes of concentrate particle in the reaction shaft, although there are some research results reported from pilot scale and commercial scale experiments (Kemori, Ojima & Kondo, 1988; Hagni, Vierrether & Sohn, 1988; Jorgensen, Taylor, Dickinson & Stevenson, 1992; Swinbourne, Simak & Yazawa, 2002; Kivinen & Tuominen, 2005), they are generally limited themselves to theoretical analysis and calculations. No studies are published concerned with the processes of matte and slag generation in the shaft, quantitative analysis of the processes, variations of matte and slag composition and morphologies of the melts along the axis of the shaft, etc.

Jan 1, 2019

By Tatiana Ravani von Ow, Leandro Bomvisinho

"The size of mills driven by ring-gear or by a gearless solution has significantly increased in the last years. This has created additional challenges for the driven equipment. The requirements for the mechanical devices and the power grid have become more demanding. Controlled soft starting and operation, especially in dual pinion mills, as well as the protection of the equipment has gained importance. The selection of the drive solution for the mill therefore becomes more critical. Besides the classical criteria such as performance, efficiency and capital costs other factors come in the evaluation of the system such as flexibility and optimization of operation, reliability and the ageing of the grinding equipment.Variable speed solutions offer significant advantages over conventional fixed speed drives due to their application specific features and process optimization capabilities, even for ball mills where these are not seen yet as a must.The initial capital costs are higher than some of the direct on-line solutions however the benefits for the operation during the lifetime of the mill generated by the use of converter solutions justify the additional higher investment.INTRODUCTIONThe method of powering mills such as AG, SAG and Ball has a long and technically interesting history. It can be said; almost every decade in the last half century had its own trend. The trend was dominated by the market demand, by the process development and requirement of the mechanical and the electrical technology but mostly by the price of the applied technology.All has started about 50 years ago with mill diameters less than 20 feet driven by fix speed synchronous or wound rotor motors with the power of about 2 MW. Around 10 years later, the mill sizes increased, but the necessary torque could not be transmitted by one pinion therefore dual pinion solutions were developed to power the mills. However, realization of the dual pinion solution was only possible when load could be evenly shared between the two pinions."

Jan 1, 2010

By Rick Wilkins

The stability of steep embankments is a major safety issue in open pit mining, highway passes, and earth filled dams. A failure in any one of these situations could mean a loss of very expensive equipment, a long term inconvenience, and more importantly, a loss of life. These possible catastrophes could be avoided by installing a reliable real time monitoring system. Robotic total stations (RTSs) give one possible cost effective solution to creating a near real time monitoring system. Repeated surveys at predetermined time intervals can automatically generate warnings if slope movements exceed a preset tolerance level. The variation in atmospheric refraction, combined with possible instabilities in reference targets, can make a monitoring system based on RTSs produce false alarms. A methodology has been developed at the Canadian Centre for Geodetic Engineering (CCGE) for reducing these systematic error effects. The methodology has been realized in the creation of a software package that has been successfully implemented at large earthen dams in California and at an open pit mine operation in British Columbia.

May 1, 2002

By D. Ouellet, G. Gagnon, B. Simser, V. Falmagne

The mining sequence at Noranda’s Bell- Allard mine calls for two mining fronts retreating toward a central pillar known as the Retreat Zone between pyramids A and C. It is clear from numerical modelling and rock mass characterization that the induced stress level in the pillar will exceed the rock mass capacity. A mining plan was developed including the redimensioning of stopes in the Retreat Zone, additional ground support and instrumentation in order to ensure the safety of the workforce and to maximize ore recovery while minimizing production delays. The mining strategy consists in allowing the rock mass to fracture and fail progressively while maintaining control of the existing openings with the appropriate support. A systematic analysis of rockbursting and caving hazards was conducted for all accesses and stopes in order to plan ground support and instrumentation needs.

Jan 1, 2004

By A. S. Moghaddam

The transportation of cemented and non-cemented mine tailings in the form of paste through pipelines is one of the main stages of paste backfill operations. For the purpose of pipeline design, the rheological properties of the materials, such as yield stress and viscosity must be determined. In this study, the yield stress of two Canadian mine tailings, for gold and copper mineralization, were studied using the vane method and slump tests. The comparison between the vane method and the slump tests indicates that the slump tests generally overestimate the yield stress values for both cemented and non-cemented paste backfills. In addition, the effects of 5% Portland cement (type 10) and mixing time on the yield stress of paste backfills were investigated. The percentage of cement as a binder agent has a direct effect on the increase of the yield stress of paste backfills. Yield stress measurements show that mixing times of 4 minutes and 12 minutes have the same effect on the yield stress values.

May 1, 2007