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By C. A. Born

This paper describes the rejuvenation of a molybdenum mine mill complex at the head of Alice Arm, 500 miles north of Vancouver and 85 miles north of Prince Rupert, British Columbia. It includes a description of the property history of the deposits and of the previous operations, together with details of the project for re-opening the mine.

Jan 1, 1979

By Z. Bibak, S. Banisi, A. Ghasemi, E. Nematollahi

"The use of large AG/SAG mills in the mineral industry has been on the rise recently due to a significant reduction in the capital and operating costs for achieving significant increases in plant throughputs. The major reason for downtimes in these mills is the time taken for the replacement of broken or worn liners. This loss of “availability” of these units has a significant impact on the productivity of these plant operations. The ability to predict liner life time and its evolving shape could help to optimize these comminution operations. In the past decades, various models have been proposed to estimate liner wear rate, but because of their empirical nature they could only be used within certain limited operating conditions. In this research, a phenomenological model which could predict the liner wear rate was proposed and tested. This model considers parameters such as; operating conditions, liner hardness, pressure on the lifter, and, relative velocity of particles and mill shell. Data from industrially measured liner profiles were taken during the liner life time at the Sarcheshmeh and the Gol-E-Ghohar SAG mills to provide a solid base to calibrate and validate the model. The comparison of the model predictions with the actual measurements of the liner wear rate showed that the results were in a good agreement at both, the Sarcheshmeh (R2=0.94), and the Gol-E-Ghohar (R2=0.97) concentrators.INTRODUCTIONAG/SAG mills are one of the most important technologies in the mineral processing industry in the recent decades. The “Availability” of these units in a plant operation is one of the most important economic parameter for evaluating their performance. The major reason for the downtime of these mills affecting their “availability”, is the time required to change worn or broken liners (Yahyaei, Banisi, & Hadizadeh, 2009; Maleki-Moghaddam, Yahyaei, & Banisi, 2012). The knowledge about the magnitude and profile of liner wear not only enables more accurate liner life estimation to prevent unwanted interruptions of the SAG milling in mineral processing plants and more strategically plan the scheduled mill outages for liner changes. It also could provide key information needed to select an appropriate liner design (Yahyaei et al., 2009; Rezaeizadeh, Fooladi, Powell, & Weerasekara, 2010a)."

Jan 1, 2016

By W. F. Harkness, D. Hodgkinson

"A non-destructive testing program was established at Crows Nest Resources (C.N.R.), Line Creek mining operation following an in-service fatigue failure of a front wheel spindle on a large haulage truck.This failure identified a definite need for improvements in the ultrasonic techniques used during the mandatory spindle integrity examinations. Initial investigations using common mining industry ultrasonic examination techniques showed that the smallest detectable cracks were 75 mm in length for the spindle types in service at the C.N.R. site. The Initial findings indicated that inadequate inspection technique design was the cause of the poor performance. To improve inspection reliability it was identified that improved ultrasonic techniques were required. Results using designed ultrasonic techniques were encouraging, with the detection of simulated and natural cracks 12 mm long achieved. The cost benefits associated with the extended spindle life, following the removal of these small fatigue cracks, far exceeded those of the expertise and effort necessary to implement and conduct the N.D.T. program.Introduction During 50 years of evolution, non-destructive testing (N.D. T.) has progressed from a laboratory curiosity to a well accepted and invaluable tool used in the assessment of material integrity. Unlike destructive testing, N.D.T. does not deform or render the material useless. Non-destructive tests may involve many applications, from the determination of a corrosion prevention coating thickness to the examination of a raw material for internal and external deformities.Within the mining sector, highly-stressed components will normally have been subjected to some form of non-destructive test during their manufacturing cycle. These tests are used to ensure the component does not contain material flaws whichmay be detrimental to its service performance.While the component may have assured quality when produced, deterioration by fatigue may occur during an aggressive service life. Large dynamically-loaded components such as haulage truck front wheel spindles are , in particular, prone to this service related problem."

Jan 1, 1987

By E. Topuz, C. Duan

"INTRODUCTIONOperations research (OR) applications have experienced a substantial growth within the mining industry during the last three decades. The purpose of this paper is to present a summary of the results of a comprehensive survey of the application of various OR techniques to the major mining activities. It is hoped. through this sur vey , that the most widely used OR approaches, the important areas of application, and future trends have been identified.This survey included more than 500 articles published in this field in English since the late 1950s. Most of the relevant literature was found in mining publications, but, in terms of quality and originality, important applications were also found in literature not related to the mining industry. The sources constituted periodicals, proceedings research reports, and a few books. A listing of selected publications from which three or more articles reviewed in this survey appear is given at the end. Operations Research MethodologiesOperations research is concerned with optimal decision making in, and modeling of, deterministic and probabilistic systems that originate in real-life situation s. One basic feature of the OR methodologies is the attempt to optimize certain design parameters, subject to a set of constraints. This distinction has been employed in the survey as a guideline for selection of the techniques covered under the title "" OR methodologies"". The methodologies thus encountered in the literature are listed below. In a few cases, simulation has not been considered because it is not an optimization method per se."

Jan 1, 1989

By D. H. Wilton, C. I. Godwin, A. J. Sinclair

"A computer-based drill core logging system used to examine computer-based drill core logging system used to examine copper mineralization hosted in volcaniclastic rocks at the Sustut deposit, in north-central British Columbia, has many advantages over conventional logging. A relatively simple format for recording geological information allows complex, but significant, geologic parameters to be recorded consistently, accurately and quickly. This allows graphical presentations and statistical interpretation of the data that lead to rapid and detailed analyses of the control and distribution of copper mineralization at the Sustut deposit.Ore mineralization is concentrated in lens-shaped bodies and is zoned from native copper cores through chalcocite, bornite and chalcopyrite to a margin containing pyrite. Chalcocite, the principal mineral, occurs mainly in volcaniclastic agglomerate characterized by a specific grain size, a narrow range of matrix and fragment proportions, and a specific sorting.IntroductionWe report here a case history of the practical application of a detailed computer-based drill core logging system applied to the Sustut copper deposit of Falconbridge Nickel Mines Ltd. The Sustut deposit, containing a few tens of millions of tons of ore grading slightly more than one per cent copper (Church, 1975), is in north-central British Columbia about 875 km north of Vancouver. The deposit is contained in volcaniclastic sedimentary rocks of the Upper Triassic Moosevale Formation, which is within the upper part of the Takla Group (Monger and Church, 1977) of basic volcanic and associated sedimentary rocks. Takla rocks occur along the eastern fringe of the Intermontane Belt in the Canadian Cordillera (Sutherland Brown et al., 1971). The deposit consists of concentrations of copper sulphides, native copper and pyrite within pods and lenses parallel to bedding in the host sedimentary rocks. These sheet-like deposits exhibit a mineral zoning from pyrite at the fringes successively through chalcopyrite, bornite and chalcocite to native copper at the core (Wilton, 1978; Wilton and Sinclair, 1979)."

Jan 1, 1980

By Jacque Turgeon, Gontran Foy

"The Mineral Research Centre of the Quebec Department of Energy and Resources has worked extensively on the development of a dry process to extract pure mica flakes from a phlogopite ore. The liberation of mica from the gangue is effected basically by impact crushing, and the ground ore is screened into several fractions, each having a fairly narrow range of grain size. Each sized fraction is then fed to an air separator where heavy grains are separated from light flaky grains. Heavy fractions are returned to hammer mills where gangue minerals are ground finer and blocky mica particles are exfoliated. A second stage of screening is performed and each fraction is sent to an air separator. This sequence is repeated until mica products are virtually free of gangue. These different fractions are then treated in a cage mill in which mica flakes undergo a more orderly exfoliation along cleavage planes. The ground mica is again submitted to a final screening stage, after which each fraction constitutes a final commercial product.This process permits the recovery of about 70% of the mica contained in the ore. The over-all process will be described along with technical details of each unit operation. Recent work on a wet grinding method to produce very fine mica will also be discussed.IntroductionRecords of production of mica in Quebec date back to 1886. Production has been more or less continuous since that time, with peak activity during the war years. Production was interrupted in 1966, but started again in 1972 when Marietta Resources and Laviolette Mining and Metallurgical Corporation started their joint operation in Canton Suzor, northwestern Quebec. Mica deposits of more or less importance exist in different parts of Quebec, of which three have attracted attention in recent years: the Canton Suzor deposit, the Canton Lamy deposit and the Canton Chasseur deposit. The Suzor orebody was first identified by Carl Faesler in 1936, who described the rock as ""brown biotite in flakes half an inch in diameter, with interstitial augite, apatite and feldspar""."

Jan 1, 1982

By R. M. Clowes

"As part of LITHOPROBE's multidisciplinary earth science research program to understand the evolution of the North American continent, studies have been undertaken in a number of key areas in Canada. In the Trans-Hudson Orogen of Manitoba and Saskatchewan, LITHOPROBE results require re-evaluation of tectonic models related to its origin. In the Abitibi greenstone belt of Quebec and Ontario, results indicate a more complex evolution for the southern Superior province, one that links with the development of gold and massive sulphide deposits. As part of the program, the seismic reflection profiling method is being adapted for the mining industry. Three examples demonstrate the subsurface information that can be obtained. In Noranda, the base of the volcanic Blake River group is imaged and reflectivity is tied to geology through well logs; in Matagami, the zone of mineralization is shown to be downdropped along a majorfault; in Sudbury, a new structural model is developed, one that shows marked asymmetry at depth and indicates that some ore-bearing units on the margins of the igneous complex may be repeated at depth. IntroductionLITHOPROBE is Canada's national, collaborative earth science research project, established to develop a comprehensive understanding of how the North American continent has evolved. Ten transects, or study areas, were chosen to investigate pivotal geological features to their deep lithospheric roots. They span the country from the Pacific to the Atlantic Oceans and from the U.S. border to the Yukon and Northwest Territories, and geological time from four billion years ago to the present. A multidisciplinary approach, which is spearheaded by seismic reflection techniques, is essential to developing complete interpretations and outstanding scientific results. LITHOPROBE also has pioneered the use and demonstrated the value of using reflection technology to determine subsurface geology in mining camps.This paper provides an overview of the transects and their significance for the tectonic evolution of North America. Two specific examples demonstrate how we detennine present three-dimensional lithospheric structure and past geotectonic processes which formed it. The application of the reflection method to imaging complex structures in ""shallow"" crystalline rocks has been developed with funding and other support from the mining industry and provincial geological surveys. Sustaining funds, however, are derived from the Natural Sciences and Engineering Research Council and Geological Survey of Canada. Emphasis has been placed on developing deeper penetrating tools for exploration of deeply buried, but economically retrievable, mineral resources near existing mines, where an expensive infrastructure already is in place. Three examples, Rouyn-Noranda in western Quebec, Matagami in northwestern Quebec and Sudbury in northeastern Ontario, illustrate these developments."

Jan 1, 1994

By L. C. Kitchener, K. Vollenwyoer

"This paper describes the development of an automated, 70-ton capacity, underground electric trolley truck at Inco Ltd. The purpose of the project is to provide a high capacity and high productivity haulage system to suit continuous loader applications in existing mining horizons where conveyor belt application is not immediately practical. IntroductionWith the start o f a program by Inco in mid-1983 to develop a continuous loader for bulk mining of our hardrock orebodies, the need for a rapid ore transportation system was recognized to match the increased extraction rates planned. Two methods were investigated, truck haulage and conveyor belt. As a result, a conveyor belt system has since been designed and installed with a continuous loader at Stobie Mine and an electric truck has been designed, fabricated and assembled, with shop testing underway. This paper deal s with the latter project. BackgroundMany existing mining horizons which could utilize continuous loaders do not have the straight runs required for conveyor belts. In these situations, truck haulage would be the only alternative of the other transportation methods that would be practical. In order to match the high productivity potential of the continuous loader, however, a more efficient trucking system is required than would be available with conventional diesel powered trucks or with electric truck designs commercially available, or under development. A higher capacity truck and an automated operation is necessary so that the application of additional units to suit increasing haulage distances matches loader output without reducing over-all productivity because of the need for additional operators.A first effort to work with a major electrical manufacturer was unsuccessful and resulted in a project delay of almost one year. In November 1984, an investigation into the concept was reinstigated with UTDC, and an agreement to start design was reached in April 1985."

Jan 1, 1988

By G. Girard, A. Larouche, J. Colbert, G. Doyer

"The Direct Chill (DC) casting process uses water to extract heat from molten aluminium and helps to control the solidification process. Many factors such as the water flowrate, water distribution around the mould and water impingement angle have significant impacts on the solidification process. It has been noted that the chemistry variation of the cooling water is also an important factor that has a major impact on the presence of defects on the ingot. A significant change in the water quality can produce defects on the ingots such as cracks, bleedouts, or runouts. Understanding the impact of water quality variation on ingots is therefore essential to ensure good ingot production and reduce defects. This paper aims at describing a new approach to follow the variations of process water quality over time. It is an original and innovative method, which is still under progress. A water quality and stability index (WQSI) is under development to evaluate changes in the water composition based on water physico-chemical parameters. The index is calculated by comparing each of the actual parameters with historical values previously modeled by a statistical law. It is a dimensionless number having an adjustable weight factor for each parameter. The positive or negative contribution of each parameter, with respect to the water cooling capacity, is taken into account to calculate the WQSI. The current selection of parameters is based on knowledge from the literature as well as on empirical experience. When the developed tool will be mature, it could be used to track water variations upon time and anticipate problems, enabling proactive actions to ensure good ingot production.INTRODUCTIONFor many years, the impact of water chemistry on heat transfer, during DC casting, has been of great interest in the aluminum industry. Several papers have been published to demonstrate the correlation between water chemistry and heat transfer (Yu, 1985), (Gildemeister, 2014). Although numerous studies do present the effects of water parameters (i. e. hardness, conductivity, oil, and grease…) on cooling capacity under controlled experimental conditions, they do not reflect the strong interactions between the parameters and variations present in a casting center. Wells and Cockcroft also demonstrated that laboratory based studies are not fully representative of real heat transfer in an industrial casthouse, there are too many factors involved (Wells, Li, & Cockcroft, 2001). In this context, it becomes very difficult to obtain a quantifiable relationship between the capacity of water to cool the ingot and ultimately the performance of the cast."

Jan 1, 2016

By John Clancy, Andrew J. Freyman

"Trends in world coal markets indicate that the next twenty years could be a period of intensive development for British Columbia's coal resource. This paper examines demand projections for metallurgical, thermal and chemical feedstock coals, with particular reference to domestic and Pacific Rim markets. Supply possibilities, from the point of view of British Columbia's competitive position, are explored, with emphasis on the interaction of such factors as capital, labour, port and transportation requirements.The paper concludes with an examination of British Columbia's strategies in light of the foregoing, and comments on the government's role in ensuring that development of the coal resource be attained in a manner consistent with over-all provincial goals and objectives.IntroductionFor the purposes of this paper the Pacific Rim is defined as including, in addition to Canada, the following: Japan, Korea, the People 's Republic of China, Hong Kong, Taiwan, the countries of the Indonesian Archipelago, Australia, New Zealand and the Pacific-bordering countries of South America and Mexico. The United States has been excluded in this definition in order to better illustrate the economic growth potential for British Columbia coal in the Pacific Rim economies.In the past decade, the Pacific Rim economies have grown faster than most other economies in the rest of the world; economic growth rates of 10 per cent were common in the region prior to the 1974 slowdown and the average rate of economic expansion in the mid-1970s has exceeded 6 per cent. Rapid expansion of international trade in the region has been a major stimulus in this process. By 1979, Pacific Rim two-way trade has reached an estimated $550 billion-about 20 per cent of world trade."

Jan 1, 1982

By Liu Yulin, Zhao Yi, Tan Qi, Liu Lei

"Hydrotalcite is one kind of layered double hydroxides, and has special crystal chemical characteristics. Due to its good thermal stability, hydrotalcite used as the PVC heat stablier has attracted scientists’ attention. In this study, nano-hydrotalcite was synthesized by the method of mechanochemistry/crystallization, using brucite, Al(OH)3 and Na2CO3 as raw materials, and added into PVC to investigate the effect of hydrotalcite on thermal stability of composites. The synthesis mechanism was suggested by virtue of XRD, FE-SEM, FT-IR. It has been indicated that at the first of dry milling process, the parical sizes of brucite and Al(OH)3 decrease, while specific surface areas of them increase by the action of mechanical force, until produced amorphous particles. In the process of wet milling, metal ions in the amorphous body, which has high surface energy, can easily react with H2O, and produce the precursor of Mg6Al2(OH)18•4.5H2O, which has the same crystal structure as hydrotalcite. Under the hydrothermal condition, anions of OH- in the interlamination of precursor are exchanged by CO32- in the solution and nano-hydrotalcite is generated at last. The thermal stability was characterized by Congo red method. The results have revealed that hydrotalcite is one kind of long-term heat stabilizer, and residual stability time increase with the rise of added hydrotalcite amounts.INTRODUCTIONHydrotalcite, one kind of anionic clays, has been attracted a great interest for researchers because of their unexpected physical and chemical properties. The general formula is Mg6Al2(OH)16CO3·4H2O, where Mg2+ and Al3+ occupy octahedral positions in the brucite-like layers, and CO32- is an interlayer anion (Hoyo, 2007). Hydrotalcite is widely used in the fields of chemical engineering, materials engineering, environmental protection, medicine, and so forth, owing to its unique capability of adsorbability, ion exchange and thermal stability (Rozov, Berner, & Taviot-Gueho, 2010; Iwasaki, Yoshii, & Nakamura, 2012; Ay, Zümreoglu-Karan, & Temel, 2011; Cavani, Trifiro, & Vaccari, 1991; Li & Duan, 2005; Lin, Wang, & Evans, 2006). As a result, the study on synthesis and application of hydrotalcite has received considerable attentions."

Jan 1, 2016

By John C. Loretto

"The paper identifies two of the main problems encountered in recent hydrometallurgical plants for the recovery of gold and silver: firstly, the plant recovery is lower than anticipated from the testwork; secondly, the metallurgical accounting figures cannot be reconciled.The principal reasons for the plant recovery being lower than the testwork are discussed, together with solutions that can minimize these problems both during the design stage and during the plant operation after the problems have manifest themselves.The reasons for the difficulties in metallurgical accounting are analyzed by reviewing the various components of the plant figures. Recommended solutions are given for minimizing this problem and the realities of obtaining accurate figures are discussed.IntroductionThe start-up over the last few years of new hydrometallurgical plants for the recovery of gold and silver has brought to the surface again a number of problems. Most of the problems have existed for some time and they manifest themselves mainly in two ways. Firstly, the plant results do not agree with the metallurgical testwork figures; secondly, the metallurgical accounting figures do not balance.Metallurgical TestworkThe plant results not agreeing with testwork figures are mainly due to:a) testwork samples not representative of the eventual plant feed;b) misinterpretation or misunderstanding of testwork ;c) plant losses;d) plant design not allowing testwork results to be achieved;e) operating deficiencies."

Jan 1, 1982

"A 3-dimensional finite element model for stress/stability analysis of rock excavations in underground mines is presented. Developed for use on personal computer under OS/2 operating system, the model employs the 8-node isoparametric brick element and accounts for such loading conditions as in situ stresses and gravity loading of the rock mass. In addition, modelling of backfill in mine stopes as in situ stress-free material is incorporated. Material failure is assessed by Mohr-Coulomb or Hoek-Brown failure criterion. A mine design example is presented to illustrate the potential use of the model as a tool for stope design.IntroductionNumerical modelling of mine structures has become a vital tool for mine design in recent years. The need to maximize ore extraction ratio and to reach deeper mineral deposits underground has led the mining industry to employ numerical methods of analysis to undertake complex ground control studies in order to better understand the ground response to mining excavations and to evaluate the ground support requirements. Thanks to the rapid developments in computer technology, it is now possible to perform very comprehensive analyses including, but not limited to, 3-dimensional, elasto-plastic, or large deformation or time dependent nonlinear analyses on personal computer.During the past ten years or so, many researchers undertook 3-D finite element analyses of rock mechanics problems in mining engineering. The following is only a sample review. For example, Chan'!' used three-dimensional finite elements to study the mechanical response of jointed granite during shaft sinking at the Canadian Underground Research Laboratory. Wang et al.(2) performed 2-D and 3-D finite element analyses of room-and-pillar mining system with flat and rolling coal seams. Thatejatu used three-dimensional finite element method to examine the problem of branching tunnels. Dolezalovaw used three-dimensional finite elements for the analysis of tunnel-face advance with partial excavation as well as full-face excavation in combination with rein for cement of the face by long anchors. Peili (5) used three-dimensional finite elements for the simulation of rock-liner interaction near the tunnel face."

Jan 1, 1992

By J. L. Barton, R. A. Murray

"This paper looks at how Syncrude Canada Ltd. is utilizing the Conveyor Belt Monitoring technology developed and patented by the Australian CSIRO and licensed to Syncrude by Conveyor Belt Monitoring of North America, Inc. The technology involves magnetizing the steel cables in the conveyor belts and detecting the fields produced by breaks, gaps or cable ends using special sensors which feed the signals into a multi- channel recorder to provide permanent traces of the various events taking place in the steel cable belts.The data is analyzed and combined with existing belt audit programs, to assist in predicting belt life, change-out criteria and belt design, belt loading and construction. All of these applications of the CBM technology leads to better utilization of resources and forms an integral part of the conveying system reliability program."

Jan 1, 1992

By H. Soltanzadeh

This paper summarizes semi-analytical and closed-form solutions that can be used to assess the poroelastic stress changes induced within a porous formation (reservoir) during a pore pressure change. Further, solutions are presented for the stress discontinuities at the interfaces between reservoirs and the rocks that surround them. When used in combination with rock failure criteria, these solutions enable relatively simple analyses of the potential for induced fracturing or fault reactivation within a reservoir or the rock immediately adjacent to it. The latter, in particular, is useful for assessing if the hydraulic integrity of the surrounding rock (i.e., the bounding seal) will be affected by a pore pressure change. The use of the approach presented in this paper is illustrated with an analysis of a pinnacle reef with dimensions and properties representative of reefs in the Zama oil field, northwestern Alberta, Canada. Scenarios of pore pressure decrease (during historical production operations) and pore pressure increase (during several years of acid gas injection operations) are analyzed, for three different idealizations of reservoir properties and geometry (two plane strain and one axisymmetric). These results suggest that that the potential for induced fracturing is not significant at any point within the reservoir or the surrounding rock for both the production and injection scenarios that were simulated. Similarly, fault reactivation was not predicted for the reservoir or any of the points that were analyzed in the surrounding rock. However, fault orientations having the greatest potential for reactivating during historical production operations were identified; thus, illustrating a means of using geomechanical models to focus geological characterization efforts on the features that are most critical to acid gas containment.

May 1, 2009

By L. A. Mells

"A laboratory test program was initiated by the Department of Energy, Mines and Resources as part of the National Uranium Tailings Program to investigate the applicability of a radium selective ion exchange complexer for removing radium from Canadian uranium mining effluents. The test program was carried out by Melis Consulting Engineers Ltd. under contract to the Department of Supply and Services using the Saskatchewan Research Council facilities located in Saskatoon, Saskatchewan.The results of this work showed the ion exchange complexer, Dowex XFS 43230.00, to be efficient in removing radium from contaminated water of uranium mining operations with the ultimate loading capacity of the resin on one type of water treated being determined as approximately 1,600 Bq/cm3 of new resin. Although this resin has potential application for treatment of effluent streams in uranium operations it has been identified that the resin efficiency and capacity is directly related to the chemistry of the water being treated and site-specific testwork is required in order to establish reliable design data for full-scale operations.IntroductionThe possible applicability of a radium-selective ion exchange complexer for removing radium from Canadian uranium mining effluents had been identified and discussed as a possible alternative to present radium removal methods during a review of disposal technology options for the National Uranium Tailings Program of the Department of Energy, Mines and Resources(1). Work by other workers(2.3) had shown the complexer to be very efficient in removing radium from contaminated water. Also, plant trials on contaminated minewater at the Mt. Taylor uranium mine in New Mexico is reported to have shown the resin complexer to be efficient under plant operating conditions.As a result, a laboratory test program was initiated by the Department of Energy, Mines and Resources as part of the National Uranium Tailings Program to investigate the suitability of this resin for Canadian uranium mining effluents. The test program was carried out by Melis Consulting Engineers Ltd. (MCEL) under contract to the Department of Supply and Services using the Saskatchewan Research Council (SRC) facilities located in Saskatoon, Saskatchewan."

Jan 1, 1985

By C. J. Edmonds

Of the gold mined in Canada over 90 percent is extracted from the ore by the process of "cyanidation". In this process crushed ore is treated with lime to provide "protective alkalinity" and cyanide, usually in the form of sodium cyanide. The gold is dissolved in the cyanide solution, which after further treatments for clarification, is precipitated by the addition of zinc dust. Wastes from the process consist of tailings which will contain cyanides. Water consumption, mill size, effluent quantity and quality are depicted in transparency (1). It should be noted that as far as the wastes are concerned it has been impossible to postulate a typical situation. Variation from the above data will occur. A summary of data from tailings pond effluents is presented in transparency (2). The figures in parentheses indicate the usual range of values for the parameter.

Jan 1, 1973

By Luis R. Fonseca, C. Raimat, C. Wendeler, A. Sanz

"Rockfall barriers are widely known as proven efficiency element to protect infrastructure by catching the rock blocks in the falling direction and absorbing the energy generated by them.It’s common in the project design phase and during installation, fix rockfall barriers for catch a high percentage of the falling blocks and in many cases consider as valid the solution when the barrier can capture all of them. However, in many cases it’s possible to consider the use of these protections, simply to guarantee a secure shed for the traffic and intercept simply the blocks that theoretically hit the road surface.The results of the high-energy rockfall protection barriers type GBE which protect GC-200 road in Las Palmas de Gran Canaria are shown in this paper.The topographic data should be especially detailed observed and even more if you want to apply the technique of ""shadow zone"" with a flexible gallery system. It should be drawn from detailed topographic maps and drawings (photogrammetric restitution) to the scales 1/1000, 1/500, or 1/200; and it is important not to ignore the presence of vertical cuts, tracks, small slopes that modify the trajectories (trampoline effect, hard points that favor the rebounds) and which are not always presented in the drawings.The ""shadow zone"" is defined as the protected area, located at a lower elevation to the line created by the rockfall barrier to except of trajectories of rocks and free from the influence of the deflection of the system under the maximum energy level for which it was designed (MEL)."

Jan 1, 2015

By M. Pierce

Empirical relations exist for the estimation of rock block strength at scales larger than standard core sizes. Two recently published relations account for the significant impact that microflaws (pores, open cracks, veins) and weathering/alteration can have on scale effect. These relations were used to estimate the rock block strength of heavily microfractured quartzite from the Bingham Canyon Mine. Predictions were compared to the results of Uniaxial Compressive Strength (UCS) tests conducted on cylindrical core samples of varying microfracture intensity and diameter. The comparison confirms the sensitivity to microfracturing suggested by existing relations and suggests that they would benefit from more detailed consideration of microfracture strength, density and persistence over a range of scales. The results of a numerical study illustrate how Synthetic Rock Mass (SRM) modeling techniques could be used to complement empirical data in the development of such relations.

May 1, 2009

By G. H. Hope, A. R. Maycock

"La Mine Doyon is a gold mining operation located in northwestern Quebec, approximately 35 km east of Rouyn-Noranda and 85 km west of Val d'Or. The mine is jointly owned by Lac Minerals Ltd. and Cambior Inc. with Lac Minerals as the manager. Production statistics as of February 1987 are 6.4 million tonnes milled at an average grade of5.8 g/t Au. Current reserves of9.9 million tonnes at 5. 7 g/ t Au to a depth of400m have been outlined. Indicated reserves below this horizon could considerably increase this reserve.The mine currently consists of two open pit and two underground mine operations, producing approximately 3600 tonnes per day of ore at an average grade of6 g/t. The ore is currently processed at the La Mine Doyon mill at a rate of1400tid and at Lac's East Malartic mill at 1950 t/d. Ore is also processed intermittently at Lac's Les Terrains Auriferes mill and at Noranda's Horne Division.La Mine Doyon is currently in the midst of a program to expand and upgrade the mill at La Mine Doyon. The expansion to 3000 t/day includes the conversion of the existing crushing and grinding circuits to a SAG (semi-autogenous grinding) mill circuit and the existing filter wash plant to a CIP (carbon-in-pulp) recovery plant. The economics of this project are based on reduced operating costs (milling and trucking) and improved recovery due to updated technology. HistoryThe area between Noranda and Val d'Or has a long history of mining activity in both base metals and gold, dating back to the early 1930s. More recently, several new orebodies have been discovered and exploited in the area including La Mine Doyon, Lac's Mine de Bousquet, Dumagami, and the Kiena operation.La Mine Doyon was discovered in the early 1970s, and brought into limited production in late 1979. The mine was started on are reserves of 2.75 million tonnes at 6.2 g/t and was, thus, considered a small, short-term operation. Mining started at an initial rate of 550 tI d with all the ore being shipped to Noranda's Horne smelter as flux. When Lac's East Malartic mill became available for custom milling, Doyon commenced shipping to that facility at a rate of 650 t/d. As a result of some equipment additions and an improved understanding of the ore, the East Malartic mill throughput was gradually increased from 650 t/d to the current rate of 1950 t/d."

Jan 1, 1988