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By E. Yalçin, A. Ünal

In transitional mineralization, the sill of the underlying variogram is relatively easily estimated, but the estimation of the nugget effect may be more difficult. This study aims to determine for massive copper deposits just how sensitive the estimations of ore reserve, economic copper content, total net value, and ultimate pit limits are to the errors of estimation in the nugget effect of the spherical variogram model. A massive copper deposit which has a log-normal distribution and a spherical variogram was simulated on a rectangular grid using the turning bands method. By using the three dimensional random kriging method, the mean block grades were estimated at four different sampling densities. The ultimate pit-limits were determined by using the two-dimensional dynamic programming algorithm. To calculate the estimation errors, the values obtained by using the actual nugget effect and structured component values were deducted from the estimations obtained using the incorrect nugget effect and structured component values. For isotropic massive copper deposits, it was found that the ratio of the nugget effect to the structured component of the spherical variogram has no significant effect on either the block grades estimated by the kriging method or on the ultimate pit limits.

Jan 1, 1992

By D. Moffat

Rio Algom Limited has mined uranium at Elliot Lake, Ontario for 20 years. The production of this energy-generating element results in the need to dispose of low-level radioactive solid wastes and liquid effluents. Because of the wet-temperate climate at Elliot Lake, the liquid effluents are of particular importance. Radium-226 is the isotope which requires most attention, and the current practice for its control is by addition of barium chloride and retention of the resultant precipitates in large settling ponds. Analyses of typical effluents and waste streams are discussed and typical levels of radium-226, thorium-230, thorium-232, thorium-228, lead-2iO, polonium-2iO, and uranium isotopes are presented.

Jan 1, 1979

By R. K. Singhal

"On the mining side the Canadian oil sands industry has become proficient in excavation and disposal of ore and overburden. Nearly twenty years of mining experience is now behind this industry. While local improvements to existing mining systems and practices will continue, it is believed that some further gains in productivity can be achieved by selectively introducing new ideas from other mining and non-mining industries. This type of technology transfer is vital for over-all cost-effective technology enhancement of oil sands mining operations.Discussed in this paper are the issues of mining equipment, equipment sizing, microprocessor and computer based technol¬ogy as applied to mine-wide data management, automation and remote control and a projection of likely mining systems in the year 2000!This paper reviews the ""state-of-the-art"" in selected surface mining systems and attempts to evaluate the forthcoming technology and its application."

Jan 1, 1989

By B. Das

"Computers have been used extensively in the mineral industry in exploration, reserves calculation, mining technology, mineral processing, etc. With respect to coal mining, there are also various applications for evaluating rock slope stability of open pits, design of open pits, underground operations, mine ventilation, ground control, data processing and management information, operations control and certain technological applications. Mine ventilation appears to be the field in underground coal mining touched on most; on the other hand, underground coal mining methods evaluation is represented only sparingly.It is therefore essential to review the status of the computer in underground coal mining methods evaluation in order to define its scope for further application. The paper discusses the roles of the mining engineer, programmer, computer operator and analyst as well as that of the computer. The important parameters will be identified and discussed along with their application for different underground coal mining methods, with their individual unit processes. Mainly, longwall face operations have been covered. Although many models have been of academic interest, they can be considered as important steps in a transition stage which will be followed by more practical applications for computers for underground coal mining method evaluations in the future. This calls for a coordinated effort from all concerned."

Jan 1, 1981

By Y. H. Hatzor, D. Bakun Mazor

"A new model for thermally-induced block displacement in discontinuous rock slopes is being explored inside a Controlled Climate Laboratory (CCL). The model is based on a hypothesized wedging mechanism that takes place inside the filled tension crack of a discrete block that rests on an inclined plane. Irreversible block sliding is assumed to develop in response to climatic thermal fluctuations and consequent contraction and expansion of the sliding block material. While an analytical expression for this model is already available, we are exploring the possibility of obtaining such a permanent, thermallyinduced, rock block displacement, under fully controlled conditions in the laboratory, to enable effective analysis of the sensitivity of the mechanism to geometry, mechanical properties, and temperature fluctuations.A large scale (approximately 0.5 m3 in volume) model consisting of four blocks has been installed in the CCL. The CCL permits accurate control of atmospheric temperature (?0.5 °C) from 6 °C to 45 °C. Harmonic temperature function is planned in advance and is controlled by a computer program throughout the experiment process. The minimum length of the temperature cyclic period for thermally-induced block displacement is calculated here based on the existing analytical model.Due to the fact that this experiment is still in progress, preliminary results will be available in the next few months. The obtained results may explain sudden triggering of rock slope failures that are not correlated with common failure triggers such as seismic activities, pore pressure build-up, or freezing and thawing of water inside rock joints."

Jan 1, 2015

By Susan W. Campbell, Bruce Regensburg

"The CIM Careers Task Force has addressed industry's concern of a perceived shortage of skilled personnel over the coming decade. The industry is faced with a fundamental shift by young Canadians away from scientific and engineering careers, coupled with the fact that today 's students know little about the minerals industry and have a poor image of it.The responses to two questionnaires which were distributed to CIM members, government, professional associations, and educational institutions, formed the backbone of the Task Force position paper, which presents a shopping list of ideas and initiatives for consideration and to facilitation by the various organizations concerned.Tackling the image of the minerals industry is part of the answer to the careers crisis. On the positive side, the minerals industry provides the allure of a treasure hunt for young people and is seen as a significant contributor to the economy. It is understood to be well paying, provide good opportunities for advancement, individualism, and travel, and to be rich in esprit de corps. Enhancement of these positive aspects of the image can take place at all student age levels.Numerous initiatives tackle the negative aspects of the image. Young people perceive the industry to be environmentally damaging, which is the most crucial aspect that needs to be addressed. The industry is seen as still in the pick-and-shovel days and as a sunset industry that is running out of ore. Work in the minerals industry is perceived as dangerous and lacking glamour. And finally, the perceived remoteness of operations and exploration is seen as a drawback to a largely urbanized student group.Tackling young peoples' curiosity and interest in the minerals industry throughout grade school and encouraging postsecondary science and engineering students to enter the minerals industry by ensuring summer employment is the second part of the equation.The CIM Careers Task Force position paper develops strategy to attract and maintain interest of students in grade school, junior high, senior high school, and in post-secondary levels. The strategy outlines initiatives targetted at each of the educational levels and action plans to accomplish the objectives."

Jan 1, 1993

By I. A. Cameron

In 1979, John Peacey and William (Bill) Davenport published The Iron Blast Furnace Theory and Practice billed as "An up to date and comprehensive treatment of blast furnaces from fundamental principles to modern operations" (back cover). As a 1979 graduate of McGill University’s Metallurgical Engineering program, I belonged to the last "beta" student group which completed the prescribed blast furnace course work before The Iron Blast Furnace Theory and Practice was published. As my career developed, I become an international blast furnace consultant and have worked with blast furnace operators and raw material suppliers on 5 continents. The blast furnace is the dominate iron making process responsible for 70% of global steel production. Blast furnace engineers have implemented many improvements by manipulating the blast furnace process metallurgy using the principles presented by Peacey and Davenport to reduce coke consumption and increase oxygen usage and blast furnace productivity. This paper briefly summarizes some key principles presented by Peacey and Davenport (1979), describes process improvements made by blast furnace operators over the 35 years since The Iron Blast Furnace Theory and Practice was published and outlines important future developments in blast furnace technology.

Jan 1, 2014

By Andrew J. Neale, Brian C. Flintoff

"In most mineral processing operations the term ""audit"" is usually reserved for the exercise of checking financial records and/or safety practices. While these activities are time-consuming, no one disputes their necessity or value. If these areas are subjected to such careful scrutiny, why is it that the same principles are not normally applied to critically examine process operation. After all, the operating efficiency of the plant impacts directly on the measures of profitability.A mineral processing plant is a complex system that has a number of distinct, but mutually dependent elements: process equipment, instrumentation, operating policies, maintenance policies, control strategies and people. To ensure maximum economic performance in the dynamic environment that characterizes a concentrator, requires a periodic review of each of these areas. However, to be useful, the study must be based on sound metallurgical principles and be conducted in a highly focussed manner. Experience has shown that the exercise is very revealing and rewarding.This paper will discuss the plant audit process and illustrate its potential value through examples taken from plant studies."

Jan 1, 1992

By Nigel J. Cook

"Detailed mineralogical examination of gold-bearing rocks, ores, concentrates and other samples should be considered an integral part of any study of a deposit for which exploitation is being planned. Adequate mineralogical study, although time consuming and often costly, can significantly improve understanding of the mineralization, can help to optimize the results of any metallurgical testing and can be of great value in case of potential trouble-shooting. The advantages and disadvantages of various examination techniques are discussed with reference to a number oj mineralogical studies oj Canadian gold-bearing samples.IntroductionVarious authors, notably Gasparrini (1983), Harris (1989) and Henley (1990), have stressed that mineralogical study of gold ores is critical to successful and efficient beneficiation. Only in cases where diagnostic cyanide leach testing is successful can detailed mineralogical examination be disregarded. Such examination of gold-bearing rocks and metallurgical products is all too often neglected because the methods involved are believed to be time-consuming, costly, and may carry a considerable degree of inaccuracy. Commonly, bulk metallurgical testing is, carried out without prior or concurrent mineralogical examination, causing the results of the testwork to be difficult to interpret, or in some cases, misleading. This, in turn, may lead to> significant delays to the project at the feasibility stage or mean that understanding of the sample is limited, preventing the introduction of prudent modifications at a later stage if problems arise. Mineralogical studies may guide the successful implementation of a metallurgical test program."

Jan 1, 1990

By C. J. Kerr

"A recent information sheet from the Mining Health and Safety Branch of the Ontario Ministry of Labour was sent to all Ministry inspectors and engineers. The subject title was' 'Two Brakes on a Hoist Carrying Persons"" and it quotes mining regulation 699, sub-section 206(i):No hoist shall be used for the transporting of persons unless it has a braking system consisting of at least two sets of mechanical brakes to stop and hold the drum for the shaft conveyance transporting the persons.The intent of the regulation is that each of these brakes is to be set so that, individually, they can safely stop the drum carrying persons and also hold the drum without movement with the maximum manload.This can be achieved in the following ways: Single Drum Hoist-one brake on each side of the drum, one brake on the drum, one brake on the pinion shaft, where disc brakes are used two separate disc brake assemblies on the disc. Double Drum Hoist, brakes on companion drum can serve as backup brake only pinion brake with one drum unclutched.Friction Hoist, one brake on each side of drum As new hoists can be manufactured easily with a two-brake system, attention will be focused on retrofitting pinion brakes to older hoists.A brake mounted on a pinion shaft is designed purely as an emergency brake in the event of main brake failure , controls malfunction, and power loss."

Jan 1, 1989

By J. L. Luo, D. G. Ivey, A. H. Adeleke

Double-edge-notched flat tensile samples of X70 steel were used for both slow strain-rate testing (SSRT) and cyclic loading testing with the notch located in the zone of interest, i.e., the weld metal (WM), base metal (BM) and heat affected zone (HAZ). By using both optical and scanning electron microscopy, the stress corrosion cracking (SCC) behaviour with respect to crack morphology and various forms of microstructure was investigated. In all the samples considered, the mode of failure was predominantly transgranular with cleavage facets around the edges of the fracture surface. The BM, with a bainitic microstructure, had the highest resistance to SCC when compared with the mixed microstructures of acicular ferrite-primary ferrite and acicular ferrite-grain boundary ferrite observed in the WM and HAZ, respectively. The effect of microstructure on stress corrosion cracking behaviour is discussed based on experimental observations.

Jan 1, 2005

By J. Thiriar

The electrolytic tan/chouse at CCR was recognized by management as lagging behind modem refineries in terms of productivity, energy efficiency and controls. The operation was also burdened by high maintenance costs of cells, floors and electrolyte recirculation systems. A bench marking program was started in 1986 to evaluate processes and other technology by visiting major copper refineries in North America, Europe and Japan. The basic principles necessary to optimize the operation were defined, and a program called CCR 2000 was prepared for approval of the necessary capital investments. This paper describes the results obtained to date and outlines the remaining work to complete the modernization program, in particular, the control of electrolytes, the elimination of the Baltimore groove and studies to modernize the stripping operation or adopt permanent cathode technology.

Jun 1, 1993

By J. E. Danoczi

Shore Gold Inc. (Shore) is presently designing a diamond processing plant for the Star and the Orion South kimberlite deposits in the Fort à la Corne area kimberlite field in central Saskatchewan. The first step in the plant is diamond liberation and occurs in the comminution section. Diamond liberation is the process of breaking up the kimberlite rock, as ?gently? as possible since essential to the diamond liberation process is the minimization of diamond damage, particularly for the larger, high value diamonds. The Southern African diamond mines traditionally use Jaw and Gyratory crushers as their primary comminution method. However, these diamond mines generally process the harder, competent kimberlite that is located in the diatreme zone as well as the root zone of the volcanic pipe. Softer kimberlite is typically located in and around the crater area of a volcanic pipe and it is this source of kimberlite that makes up the majority of kimberlite for both the Star and Orion South deposits. These softer kimberlites can be readily broken up using abrasion and attrition imparted by AG mills, this being the preferred method of comminution for minimizing diamond damage.

Nov 1, 2011

By Ferri P. Hassani, Riadh Bouzaïene

"Selected methods of pressure loss predictions in horizontal slurry flow in pipelines are presented. For a given combination of flow velocity, solids concentration and particle size, the slurry and its flow conditions are described, and an appropriate method of pressure loss prediction is outlined. The wide range of conditions treated in this paper may be found in practice in areas varying from the hydraulic transport of low concentration slurries to dense-phase conveying of paste backfill in underground mines.IntroductionThe hydraulic conveying of solid particles in pipelines is a major component of the mining and mineral processing industry. Whether the objective is to transport ore to the processing plant or to make use of mill tailing as backfill material; the need for well designed, economical hydraulic conveying systems is recognized.The contribution of this paper is part of an on-going research program at McGill University involved in optimizing and developing techniques for total mine waste disposal. One of the main concerns in the conveying of solid-liquid mixtures is the prior knowledge of the pumping power input required. This energy requirement is directly proportional to the pressure losses incurred in the pipeline system. Understanding the sources of such pressure losses and predicting their magnitudes should enable the system designer to make informed decisions regarding the optimum mode of hydraulic transportation commensurate with the over-all requirements of the operation.This paper is an attempt to classify pressure loss prediction methods encountered in the literature for solid-liquid mixtures. In spite of the large number of publications spanning thirty years of research in the field of slurry transportation, it is sometimes difficult to correctly identify the appropriate methods applicable to a given situation. This is partly due to the inherent complexity of the mechanics of slurry flow and the ensuing uncertainty about the nature of the flow regime under investigation.Our approach is to use three fundamental parameters, namely: flow velocity, solids concentration and particle size (for solid particles with a given density) to characterize the slurry and the flow conditions, and to match them with an adequate pressure loss prediction method. For each combination of flow velocity, solids concentration and particle size, a description of the most likely prevalent flow conditions and some known methods of dealing with them will be presented. Qualitative definitions of ""high"" and ""low"" magnitudes of the aforementioned parameters will be given as a general guide to the classification scheme presented in this paper."

Jan 1, 1992

By G. J. Desroches

"In order to improve zinc plant productivity, areas of low efficiency were identified. As a result, solution purification was improved, additional dust precipitator capacity was made available and a new zinc casting plant was installed. The effects of these and other changes are discussed and the expenditure and benefits reviewed. HistoryThe operation of the Flin Flon metallurgical complex including an electrolytic zinc plant commenced in October 1930. The design of the zinc plant was based on that of the Commonwealth Mining and Smelting Company at Trail, British Columbia, the Anaconda Great Falls Montana Plant and the Electrolytic Zinc Company plant at Risdon, Tasmania.The plant began with a design capacity of 60 tons per day and currently produces 255 tons per day. Since plant start-up, approximately 3.5 million ton s of zinc metal have been produced, most of it exceeding special high-grade specifications.IntroductionThe facility incorporates the basic process steps of roasting, leaching, purification, electrowinning and casting. Figure I details the flowsheet. During the late 1970s, management recognized that in order for the zinc plant to continue operating, it was necessary to introduce cost-effective practices.Study groups, consisting of design engineers and operations personnel, were formed to investigate the details of plant revisions.The objectives were to improve productivity by reducing manual labour, reducing energy usage, increasing zinc recovery, increasing metal output and reducing costs.This paper details the changes made during the period 1979to 1986 and shows how these changes have affected the productivity and economics of the zinc plant operation."

Jan 1, 1988

By K. C. Corin, M. S. Manono, J. G. Wiese

Depressants play a crucial role in the flotation of PGM bearing ores as they prevent naturally floatable gangue (NFG) from reporting to the concentrate. This action is regarded as critically important because less dilution of the concentrate means lower costs for downstream processes. However, abnormal water conditions (such as high concentrations of ions) in the flotation system can modify the selectivity of these depressants. It is well known that the existence of selected electrolytes in water can alter the behaviour of some polysaccharide depressants by enhancing their adsorption onto gangue minerals and thereby prevent naturally floatable gangue from moving into the froth phase. Concurrently these same electrolytes may enhance frothability, owing to their stabilising effect on the bubbles within the system. Plant water at various ionic strengths was investigated against depressant type and dosage in order to understand electrolyte-depressant interactive effects during the flotation of a Merensky ore, using entrainment, rate of NFG recovery, and total gangue recovery as proxies. The study showed that the rate of NFG recovery per unit mass of water decreased with increasing ionic strength at all dosages, however the total amount of gangue reporting to the concentrate increased with increasing ionic strength at all depressant dosages. Thus, this paper attempts to consider the effects of both ionic strength and depressant dosage as individual factors within flotation. It further looks to investigate whether any interactive effects exists between these two factors when considered simultaneously.

Jan 1, 2016

By D. F. Hambley

"In designing are passes f or underground mines specific consideration should be given to unimpaired flow of broken rock, the dump point, and typical practices f or overcoming operational difficulties. Design features such as branches, bends, and knuckles should also be considered. This paper pro vides engineering information and various criteria for designing are passes, draw points. feeders, and support systems, together with several illustrative examples.IntroductionOre passes are the primary mean s o f vertical transfer of mined ore to the ore bins and loading pocket from which the o re is hoisted to the surface (Fig. 1) . While the words "" ore"" and ""ore pass"" are used here, such transfer systems ca n be used for any broken rock.The most extensive ore pass systems are found in caving and sublevel stoping mines. Extensive ore pass systems are also found in multilevel mines having steeply dipping orebodies. In more flat-lying orebodies , ore pass systems are sometimes used in conjunction with conveyor systems .Two decades have passed since the principles of the flow of bulk solids were formulated (Jenike, 1961, 1964; Johanson and Colijn, 1964; Kvapil , 1965). However, few published papers are available that discuss the design criteria for ore pass systems. Therefore, the aim of this paper is to provide the information necessary for good o re pass design .Rock Flow in Ore Pass SystemsIf an ore pass system is to fulfill its function, the transfer o f material must occur in an orderly fashion and in such a way that the full size of the opening is employed effectively. Apart from un controlled flow at the drawpoint, or outlet , whose design will be considered later in this paper, two occurrences may impede flow in an ore pass, namely:• Hangups due to interlocking arches.• Hangups due to cohesive arches.Prevention of each of these problems will be discussed in succeeding sections of this paper. A third problem piping, is related to the ratio of the drawpoint size to the o re pass size and will be discussed under drawpoint de sign."

Jan 1, 1987

By Patrick J. Williams

Outline -An Australian View On: ?IOCG defining features and occurrence ?Variable exploration characteristics ?Extracting value (gold metallurgy) ?Recent exploration experience(case study)

Apr 1, 2005

By J. A. Finch, G. Labonté

"A long-standing objective has been to obtain interpretable measurements of the oxidation-reduction potential in mineral slurries. For this purpose several sensing electrodes (black platinum wire, platinum foil and spiral, gold foil and spiral, and sulphide minerals such as chalcopyrite and galena) were investigated to determine their response to the presence of sulphide minerals in the pulp, and to the addition of reagents commonly used in flotation. The observed discrepancies between the electrodes may be explained using a combination of the classical mixed potential model for complex solutions and the probability of contact between the mineral particles and the sensing electrode. It is shown from laboratory testwork that gold spirals are preferred over platinum electrodes. Finally, some of the practical aspects of using the electrochemical measurements in a plant environment are discussed.IntroductonThe interpretation of flotation of sulphide minerals in terms of electrochemical (electron transfer) processes has brought new possibilities for process control of selective flotation. Investigations on massive and compacted particulate bed electrodes have shown that the flotation of a given mineral in the presence of a collector can be controlled by the potential induced on the mineral surface. Also, phenomena such as collector less (self-induced) flotation, activation by heavy metal ions, and natural selectivity sustained by galvanic coupling during flotation might also be controlled by electrochemical means.The technique for measuring electrochemical potential in slurries is an adaptation of that used for solutions. The measurement of the oxidation-reduction potential of a solution (ORP , Redox, Eh) is usually carried out by immersing a noble metal electrode (platinum, gold or silver) and a non-polarizable reference electrode: Standard Hydrogen Electrode (SHE), Standard Calomel Electrode (SCE), or silver/silver chloride (Ag/AgCl) in the solution. (The abbreviation Eh implies the SHE is the reference electrode.) The potential difference between the two electrodes is measured using a high impedance electrometer. ASTM standard D 1498-76 (revised 1981)(1) covers the practical details of such measurements; however, it does not deal with their meaning either in complex solutions or in mineral slurries ."

Jan 1, 1988

By J. M. Beeckmans, S. G. Butcher, M. Goransson

"The counter-current fluidized cascade is a novel and potentially efficient pneumatic gravity separation device. Data are presented on over 150 runs of cleaning Alberta thermal coals, covering several size ranges. The coarser sizes of coal were processed in admixture with a fluidizing medium consisting of 0.5-by 0.1-mm hematite (or magnetite) and limestone particles. The partition curves for coal particles larger than about 3 mm, mixed with fluidizing medium, showed that the sharpness of separation achievable with the cascade approaches that of wet heavy medium processes, whereas with particles in the size range of 3 by 0.6 mm the sharpness of separation was comparable to that of a Baum jig. Useful cleaning was also achieved with particles smaller than 0.6 mm , Throughput rates of up to 11 tonnes per metre width of cascade per hour were achieved, with no indication of a deterioration in performance.IntroductionPneumatic coal beneficiation has steadily lost ground vis-a-vis hydraulic beneficiation during the past quarter century, primarily because of the sharper separations achievable with the latter methods. Nevertheless, there are certain inherent advantages of pneumatic separation methods which would give them an advantage in the market place were it possible to increase their efficiency to be technically competitive with those of hydraulic processes. These advantages are a dry product, resulting in a higher calorific value per ton, and avoidance of the problems associated with treatment and storage of process waste waters. Also, although it may be necessary to dry the raw coal prior to pneumatic processing, the dry rejects produced constitute an ideal fuel for a fluidized-bed combustor, which could provide heat both for drying the coal and for other purposes."

Jan 1, 1982