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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 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 E. Busse, J. E. Burgener, J. G. Eacott, M. C. Robinson, P. E. Burgener

"This paper presents a preliminary assessment of the technical and economic feasibility of a caustic leach - electrowinning process for the recovery of zinc and lead from electric arc furnace baghouse dust at a mini-steelplant. Recent studies and literature are referenced briefly as they pertain to the formation and characterization of dust, toxicity considerations and alternative dust treatment and disposal options.Laboratory testwork results, published data, pilot plant experience and anticipated influences resulting from recycling residues are used for the purpose of developing a conceptual design for a caustic leach - electrowinning plant to treat 15,000 tonnes/year of dust at a one million tonnes /year capacity steelplant in Canada.Target economic studies, comprising preliminary estimates of capital and operating costs, revenues and rate of return are presented. Economic and commercial considerations concerning the relative merits of dust treatment at a centralized facility compared with an on-site plant are discussed.IntroductionThe treatment or disposal of mini-steelplant electric arc furnace (EAF) baghouse dust has been given increasing attention in recent years for two principal reasons. Firstly, the dust is now classed as a hazardous waste material under V.S. EPA regulations which prohibit its disposal in dumps other than controlled landfill sites. Secondly, the dust contains certain metal values, notably zinc and lead, which may be economically recoverable, depending on the costs associated with disposal resulting from enforcement of the EPA regulations. Other metallurgical dusts and waste materials, from both ferrous and non-ferrous operations, may require the same considerations as EAF baghouse dust.Several studies have been carried out to examine various aspects of dust treatment but few commercial plants are in operation. Technology employed uses pyrometallurgical techniques. Commercial-scale hydrometallurgical plants are not known to exist although small-scale plants are frequently more economically attractive than their pyrometallurgical counterparts which generally require economies of scale to be viable.The concentration of mini-steelplants in northeast V.S.A. and southeast Canada merits study to determine whether or not dust treatment for metals recovery is a commercially feasible alternative to disposal.This paper examines the technical and economic feasibility of a caustic leach - electrowinning process for the recovery of zinc and lead from EAF baghouse dust at an on-site ministeel plant processing carbon steel scrap and discusses economic and commercial considerations pertaining to dust treatment at a larger, centralized facility."

Jan 1, 1984

By N. E. Chaouai, M. Lavigne

"Indicator kriging is one of the non-parametric geostatistical techniques, ideal for estimating the reserves of irregular mineralizations (e.g. gold, uranium, platinum, diamonds, etc.). Such mineralizations are characterized by variograms which are very sensitive to extreme values (outliers) and very difficult to model.The classical approach to this problem in the industry is to trim off these high grades using arbitrary empirical upper limits established either from practice or subjectively. Contrary to this simplistic approach, indicator kriging discretizes the histogram of the grades (usually log normal) in several classes and carries out interpolation separately for each class. This paper gives an overview of the differences between ordinary and indicator kriging along with the steps required to carry out indicator kriging. The paper concludes with a case study involving a gold deposit estimation.IntroductionParametric geostatistics (ordinary kriging) has given us satisfactory results over the years in estimating the reserves of well behaved deposits with coefficients of variation close to 1 (e.g. sedimentary and porphyry type deposits). However, numerous problems have been encountered in estimating irregular mineralizations (e.g. small vein deposits of precious metals) with high coefficients of variation in the range of 2 to 5. Such deposits are characterized by a very small proportion of extreme values (outliers) which create distortions on the variograms (pure nugget effect) and render them useless(1,2).The solution often followed by the mining industry today is to trim off these values based on empirical limits. These limits are derived either by comparison with production results (or bulk samples) or by geological interpretations. Needless to say that such manipulations can lead to serious errors in estimating ore reserves (usually underestimation of total metal quantity), especially when production results or bulk samples are absent.On the other hand, the solution followed by the geostatisticians in the past was to smooth out the data using transforms (e.g. normal-score or natural logarithms). Such transforms are nonlinear and they required non-linear estimation techniques such as disjunctive kriging (DK) or multivariate gaussian kriging (MG) which require normal related hypotheses, not necessarily true in geology.Nonparametric geostatistics (indicator and probability kriging) have been -developed in order to handle these problems related to highly skewed distributions."

Jan 1, 1990

By E. Henderson

"This paper outlines the upgrading of a double-drum 2000 hp cage hoist to provide fully-automatic operation from shaft station control panels. The application utilizes programmable controller technology to provide all necessary functions for movement of personnel and material to 22 locations in a 4000 ft shaft.Various functions involving special design considerations such as ""chairing"", ""jogging"", and three modes of ""multi-level calling service"", are outlined. The use of higher level PLC functions to optimize memory utilization and simulate ""elevator service"" required the addition of a comprehensive fault finding software section to aid in troubleshooting.This paper will deal primarily with the automation portion of the project with references made to other pertinent aspects which were prerequisite to automatic operation. It is not intended to deal with every design detail, but rather to provide an overview of what can be done in the area of automation for those considering such an application. INTRODUCTIONEarly hoisting control systems provided only the essential elements of control, leaving many responsibilities with the operator. With advancements in various areas of technology, electromechanical devices were incorporated to enforce slow-down in end zones, control acceleration rates, monitor safety devices, etc. Brake control systems were supplied to allow for ""single-stick"" operator control, regulated deceleration during emergency brake applications, etc.These additions enhanced the over-all performance but were generally confined to speed and current regulation. Some mechanical devices, such as travelling nut limits, etc.; were used to provide ""position"" control to multiple locations within the shaft. These devices, in conjunction with rather extensive relay control panels, did allow for the establislunent of some automatic cage hoists . The hoists were often limited to service from point ""A"" to point ""B""', involving a limited number of levels due to the complexities of the mechanical interfaces employed. Only limited systematic work sequences were possible . .Programmable Logic Controllers (PLCs) were introduced into industry in the mid-70s and have since gained acceptance in mining applications such as pumping, ventilation, ore handling, etc. This technology, being ""software"" based, allows complexities to reside in the program rather than increasing the number of physical control elements. This has opened the door into hoisting systems for automatic loading and hoisting of ore as well as a means to achieve a comprehensive package of automated cage hoisting functions."

Jan 1, 1989

By Hajime Miki, Gde Pandhe Wisnu Suyantara, Ahmed Mohamed Elmahdy, Hidekazu Matsuoka, Kyushu University, Tsuyoshi Hirajima

"Selective flotation of chalcopyrite and molybdenite was studied using various surface treatment methods such as electrolysis, ozone treatment, and plasma. Oxidation via electrolysis method indicated that only chalcopyrite surface is affected by electrolysis due to conductivity difference with molybdenite. Oxidation treatments and XPS analyses indicated that chalcopyrite became hydrophilic due to deposition of oxidized iron on its surface. Various oxidizing methods also showed that chalcopyrite was selectively oxidized and this can apply selective flotation of chalcopyrite and molybdenite. The possible mechanisms are proposed in this work based on surface analyses and thermodynamic calculations.INTRODUCTIONCopper sulphide minerals often associate molybdenite (MoS2) which is one of the most important by-products (Wills, 2006). It is important to recover molybdenite perfectly not only since molybdenite is valuable mineral, but also contamination of molybdenite into copper concentrate or contamination of copper mineral into molybdenite concentrate indicates penalty for both concentrate values (Wills, 2006). Conventional separation of copper sulphide and molybdenite has been achieved with sulphide bulk flotation followed by selective molybdenite flotation with NaHS addition since NaHS works as a depressant for copper sulphide. However, this current process shows imperfect molybdenite recovery and depressant such as NaHS needs to be used under specific flotation plant since it might be environmental contaminant. Hirajima et al., (2014) have been studied selective flotation of molybdenite and chalcopyrite (CuFeS2), which is the most important copper mineral, with plasma pre-treatment. They reported that plasma pre-treatment process followed by washing treatment can improve molybdenite floatability and depress chalcopyrite. This result is attributed to surface oxidation and selective conversion of chalcopyrite and molybdenite wettability. It may be hypothesized that another surface oxidation methods could give a similar result as plasma treatment process. To test this hypothesis, in this study, as comprehensive study of oxidation effect, various oxidation methods such as electrolysis, ozone, and plasma were investigated. Electrochemical measurements, thermodynamic calculations to predict the chemical reactions happened during the process, various surface analyses, and flotation experiments were carried out."

Jan 1, 2016

By Doug Barnstable

"Quinsam Coal Ltd. is assessing the potential of developing a thermal coal deposit near Middle Quinsam Lake on Vancouver Island. The coal reserve outlined is classified as a high-volatile, bituminous ""A” steam coal and is composed off our separate seams of varying quality within the Late Cretaceous Comox Formation.Open-pit mining methods will utilize a walking dragline and a truck / shovel module as the primary stripping tools. Following washing and mechanical drying in a Baum jig preparation plant, the coal will be transported to the proposed dock at Campbell River for shipment via 55, OOO-DWT vessels to world markets. The paper will outline the development and status of the project to date. IntroductionQuinsam Coal Ltd. is a joint venture of Weld wood of Canada Ltd. and Luscar Ltd . The participants propose to develop a thermal coal mine in the Middle Quinsam Lake area, 17 miles inland from Campbell River on Vancouver Island (Fig. I). By acquiring all the assets of Canadian Collieries in 1962, Weldwood also came to own the coal rights of the area proposed for development. Luscar Ltd . ha s been designated as project manager until completion of construction and thereafter will act as operator of the mine.Surface mining methods will be used to produce approximately 1.0 million short tons of coal annually from the Quinsam property. Seven separate mining pit s will be developed along with the supporting minesite facilities, including a proper paration plant. Transportation routing to Campbell River and the establishment of docking facilities will be required. The initial economic life of the mine is 12 years, with the provision to extend this in the future by developing higher-ratio, auger or underground reserves."

Jan 1, 1980

"Since the publication of a literature review on this topic (McIvor and Finch. 1986), the author has been involved in more than thirty rod milling efficiency tests at seven different milling operations. There have also been several interesting additional articles on rod milling found in the literature. This update describes the most important findings from investigations carried out since the previous review, as well as developments in the techniques used to evaluate the grinding efficiency of rod mills.Rod Mill Power DrawA series of power draw versus charge level measurements were taken on the rod mills at Leg Mines Selbaie and Kidd Creek Mines Limited (McIvor. 1989). These revealed a significant (about 10070) loss in power draw with the installation of new liners, a common observation among rod mill operators. This loss in power draw depends on the liner design, particularly the average thickness and lifting face profile of the new liner. The theoretical power usage of both mills was approximately 5070 lower than that given by the Allis-Chalmers power draw formula (Rowland. 1982).The shape of the power draw versus charge level curve suggested an opportunity for reducing media consumption. By increasing mill speed, power draw could be maintained with a smaller mill load, most significantly for mills operating with high charge levels. Analysis of data from 62 installations confirmed this (McIvor, 1989). On average, a 10 percentage point increase in critical speed results in a 15070 in specific media consumption (Le. kg of steel consumed per kWh of energy consumed). Table 1 lists a number of relatively high speed rod milling installations. No negative effects on the drive train, liner life, or the tendency for rods to tangle have been reported. A reduced lifting angle of the new liner leading face (e.g. 45 versus 90 degrees from the mill perimeter) is recommended for higher speed rod mills (Leclerq, 1990)."

Jan 1, 1995

By Rory S. McLaren

"Cost per ton as it relates to mobile underground vehicle maintenance and repair is invariably astronomical. The reason: the mechanic replaced a ten micron filter with a 250 micron filter because it appeared to be physically identical; the purchasing agent bought ""Brand X's"" filter because it was 25% cheaper- the result, a filter life 30% less; the hydraulic pump was sent for repair at a cost of $2000.00 and failed shortly after installation; pumps are failing because there is no testing equipment available in the workshop.This paper will identify a number of the common pitfalls resulting in high costs, and offer solutions to bring these costs to within acceptable limits.The following key issues will be discussed:A. Genuine parts replacement versus ""Brand X""B. Evaluating outside repair shopsC. The influence of environmental conditions on optional equipmentD. Personnel trainingE. Servicing and testing equipmentIntroductionThere is an old English aphorism, ""Look after the pennies, the pounds will look after themselves"".This paper is aimed at the pennies.Genuine Parts Replacement versus ""Brand X""High interest rates and floundering mineral prices are forcing many equipment owners and operators to purchase ""Brand X"" or ""Pirate"" parts in order to survive. ""Pirate"" part manufacturers invariably offer lucrative discounts which are most appealing to the average purchasing agent whose responsibility it is to save money. Unfortunately, in most cases, there is a tradeoff involved; when the price drops so does the quality, which can adversely affect owning and operating costs. Unless totally obvious, ""original"" or ""pirate"" part metamorphosis requires scrupulous analysis by competent individuals.Hydrostatic transmissions have been used successfully for many year s in various industries. They found their way into mobile underground loaders in the early seventies and have since become very unpopular in mining circles due to their apparent ""inherent unreliability"" and near ""prohibitive"" repair costs. The big benefit of the hydrostatic transmission is compact component packaging which enables the machine to work in very small headings."

Jan 1, 1983

By Leroy G. Hagenbuch

"IntroductionAn integrated Truck Management Information System (Truck MIS) evolves as seemingly separate functions combined to yield a single homogeneous result / product. The concept of a computer integrated Truck MIS includes truck dispatch, truck maintenance management and truck weighing.A truck management system is only as good as the information / data bases input to it. The concept of an integrated system works best with automated data gathering. Automated data gathering provides timely and normally, the most accurate historical information/data bases. Data bases are, however, historical, which is a problem to be overcome in a computerized truck management information system, especially in regards to a truck dispatch system as loading sites / loading conditions and some dump site conditions continually change. As these changes occur, data base s must change as well, and thus the need for the continual update of data bases that the computer uses for a Truck MIS.For a truck dispatch system to achieve reliability / viability, dispatch decisions need to revolve around real time data gathered in an automated way. Integration of all truck management function s through automated data gathering lead s to the best over-all system.An integrated system is a combination of many different factors and is only as good as each factor / building block put in the system. With the proper building blocks, an integrated Truck MIS is very feasible - an MIS System that includes weighing, time and motion study, truck maintenance and maintenance management, as well as truck dispatch.Truck MISAn integrated Truck MIS provides for truck dispatch as the ultimate end result, a truly automated /integrated truck dispatch system (to function non-operator-dependent). The following comprises its central building blocks:-Time.- Haul Cycle Segments.Truck Status, i.e. Load on truck,- being loaded,- loaded,- unloaded,- in service,- out of service.- Vehicle Location.Loading Equipment Status.- in service,- out of service.Optional- distance travelled in each haul segment.With this data provided on a non-operator dependent basis, it is possible to build good data bases so a computer can make truck dispatch decisions. Knowing what information is needed as the central core to a good Truck MIS, how can this information be automatically gathered and fed into a central control computer?"

Jan 1, 1986

By J. G. Mieczaniec

"A key element for a successful mining operation is the grinding circuit. It must be reliable, maintainable and must perform to or above design capacities for 95% of the time. Once chosen and installed major modifications are either prohibitive or very expensive. The selection of mills and drive system is probably the single most important decision made within the concentrator complex.Economic studies revealed that the optimum expansion for Lornex was a 68070 increase in plant throughput. This indicated that the new mill would have to be larger than the existing 32-foot mills.The Lornex ore has a wide range of hardness which has a great influence on mill throughput (Table 1). To smooth out the fluctuations, a blending program ha s always been in effect at the mine, coupled with ball charge control for the primary mills. As can be appreciated, an optimum balance is difficult to achieve. A sudden change to so ft ore with a high ball charge puts the mill into jeopardy with a constant speed drive.The blending philosophy would continue after the expansion, but with the addition o f a second primary crusher, it was envisaged to have the new mill process harder ore to maintain production targets. In theory, the new mill would have a proportionally larger ball charge than the existing mills.This scheme makes the new mill vulnerable for processing so ft ore for a fixed speed mill. Thus, variable speed seemed an attractive option.In early 1979 prominent mill manufacturers were invited to submit proposals for the new mill. Fixed and variable speed mills were to be considered with mill size ranging from 32-foot to 36-foot diameter. The proposals were to include the drive, ball charge, % critical speed, couplings, gears, etc. - the complete package. The recommendations were variable with most manufacturers submitting several alternatives. Recommended mill speed varied from 68% to 78% critical. The concept of variable speed was becoming more attractive, Lornex ultimately decided on a twin DC motor drive system for a 34-foot diameter mill.After start-up it was discovered that best throughput occurred at 78% mill critical speed or top speed of the drive motors. The motor speed range was adjusted upward from 186 to 200 rpm. Today the mills operate at 79% critical or a motor speed o f 193.5 rpm.Clearly the selection of the variable speed mill allowed the flexibility to optimize throughput."

Jan 1, 1985

By J. G. Whellock, J. W. Matousek

"In spite of their importance to the economics of many metallurgical projects, the values and technical aspects of precious metals losses in smelting operations are relatively undeveloped subjects. This paper attempts to provide a condensed overview of precious metals losses in pyrometallurgy, using some of the limited production and experimental data available. It is intended for three general groups of metallurgists - operators attempting to improve recoveries, cost-accounting engineers making estimates of metal losses in new or modified smelting plants, and research engineers and students.Distribution coefficients of precious metals, the ratios of metal or matte assays to slag assays, are convenient means of comparing smelting processes and the tendencies of the different metals to enter the slag. For silver in lead blast furnaces this ratio is approximately 250;for gold and the platinum group metals in submerged-arc, electric furnaces it is 900. The ratio for gold and PGMs in converters varies with the degree of oxidation of the charge. The over-all cycle-average for industrial installations is tentatively estimated to be 35.IntroductionThe magnitude of precious metal s losses in pyrometallurgical operation s is difficult to assess. The primary producers are generally reluctant to discuss the subject. The by-product producers (the large sulphide smelters o f copper , nickel, and lead) might be more willing to disclose information, but these have precious metals in their feeds in such dilute quantities that accurate accounting is extremely difficult. It is not until numerous processing steps have been taken t hat the precious metals become sufficiently concentrated to permit acceptably accurate sampling and analytical procedures to be followed. Thus, knowledge of the precious metals contents o f the intermediate mattes and slags may simply be unavailable."

Jan 1, 1990

By Peter N. Calder, Louise H. Michaud

"An interactive mine planning package has been developed to aid with the tasks involved in generating dragline mine plans. This package employs recent advances in PC-based,3D computer graphics and 3D geologic modelling. A Gridded Seam Model (GSM), capable of modelling rugged topography and multiple coal seams, including folding and faulting, is used to generate the geologic database This model is then integrated with an interactive graphics mine planning system in order to develop one model and one database for the generation of the mine design, the depletion of the coal reserves and the removal of waste material.As well as offering large potential saving in the time required to carry out the planning tasks, the system offers immediate visual feedback to the planning engineer. This can greatly aid in the conceptual understanding of complex geology and mine plans and can allow for the evaluation of a number of mining options within a reasonable time frame.IntroductionThere are a large number of variables that must be taken into account during the development of a dragline mine plan. This is especially true when developing a mine in mountainous terrain, where there is a lack of continuity of the geology and topography over the mine site. Until recently, the complexity of dragline mine plans has prohibited the development of a universal mine planning package that is applicable to all geologic and topographic situations. The majority of the commercial programs that are presently available to facilitate dragline mine planning have been developed for specific mine properties or are limited in the coal geology and mining methods that they can simulate (Brown and Clifford, 1983; White 1983; White and Jones, 1984; Sadri and Lee, 1982; Dagdelen, 1979)."

Jan 1, 1993

By R. Harrisson, K. Esmaieli

Brunswick mine employs an ore and waste pass system for material transfer. This paper reviews the evolution and performance of ore pass systems at the mine. It presents the range of selected configurations, inclination, dimensions, etc. Select case studies are used to address the influence of structure, stress and materials handling on the longevity of the employed ore passes.

Jan 1, 2008

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 K. G. (Ken) Thomas

"This paper gives an insight into the various processes available to treat gold ores. A brief overview is given of the various types of refractory gold ores. Particular emphasis is given /0 comparing the costs of oxide vs refractory gold ore processes, inclusive of grinding through to dore bar.HistoryThro ugh time gold has been recovered from the earth's crust by various mean s. Five major historical steps can be identified for metallurgical processing as shown in Table I .Gravity concent ration started with, for example, river bed panning and developed to more sophisticated processes such as the Johnson concentrator, belt concentrator and jigs. The South African gold fields were a major developer of gravity concentration processes during the first half of the twentieth century.As coarse free gold became depleted, stamp milling, in conjunction with amalgamat ion , was developed. Basically, rock was crushed under large mechanical hammers an d the gold collected in mercury . The mercury was then evaporated in a retort to leave sponge gold for further fire refining.As deposits became deeper and gold finer, the gold became more difficult to recover ; fine grinding was required to liberate the gold. In the 18905, MacArthur and the Forrest Brothers of Glasgow, Scotland, introduced the cyanide pro cess for dissolution of gold and its subsequent precipitaiton by means of zinc. This process, in vogue until the early 1970s, was commonly referred to as the Merrill-Crowe process for recovering fine gold .Activated charcoal was used as a means of recovering gold from solution in the 1880s, especially in chlorination plants in Australia( l). Two factors probably retarded the development of carbon instead of zinc-based processes during those year s. First , there was no satisfactory procedure for the elution of carbon to allow its recycling and, second, the development of the Merrill-Crewe process for gold recovery by zinc cementation probably discouraged any further work on the use of carbon"

Jan 1, 1991

By P. W. A. Mayer

"As the push toward the northern regions of Canada steadily increases to exploit the rich mineral reserves, interest is steadily rising in respect to accessibility and climatic conditions and the problems posed thereby. In twelve years of operation, the Iron Ore Company of Canada, and associated companies, have found, through advanced technology, ingenuity and, most of all. need, some of the answers to the running of a profitable year-round open-pit mining operation."

Jan 1, 1966

By Amir Asadi

Various damage modes that evolve with time in polymer composite laminates, such as transverse cracking, vertical cracking, delamination, and fiber fracture, as well as the interaction among them, influence the time-dependent degradation in modulus (creep) and strength (creep rupture) of polymer composite laminates. This study is focused on modeling the time-dependent evolution of transverse cracking in [90] plies of a multidirectional polymer composite laminate [0m/190n]. This model uses a two-dimensional variational analysis to determine the stress state at any given creep time. The elastic stored energy, determined using this stress state, is compared with a critical energy for fracture to determine the crack evolution with creep time. Model predictions are compared with experimental results to validate the model.

Jan 1, 2010

By G. A. Buckland

"The development, in Ontario, of a common industry-wide program for the development of skills for employees in underground hard-rock mining is described. This program is designed to increase the productivity of individual workers by improving their skill levels, while at the same time ensuring that employees are instructed in the requisite safety and health aspects of performing various underground tasks. The program's development through a management-labour-government tripartite approach is described. How this program was coordinated with new Government Regulations on Occupational Health and Safety dealing with mandatory training of underground employees is also outlined. IntroductionThis paper will describe briefly what modular training is all about and outline why, and how, it was developed in Ontario on an industry-wide basis. Simply stated, what's been accomplished to date is an industry-wide program for developing the mining skills of underground production employees.The basic objective of this program is to improve the productivity of underground workers. It involves developing an employee's skills to improve his productivity and, because working productively involves knowing how to do a job safely, the program includes instructing an employee in the various safety and health aspects of underground work. An important and, I believe, distinguishing point about the development of this program is that it has been done with the full participation, cooperation and commitment of management, labour and government.It's of considerable interest to note that companies in Ontario who are now using this program are finding that new employees are approximately six months further advanced in productivity than was the case before its use, and in some cases the frequency of accidents has shown a reduction among those employees who have taken this program as compared to those who haven't"

Jan 1, 1980

By Norman J. Tienkaivip, Christopher J. Preston

"This paper describes the use of electronics for physical measurement and computer analysis in both open-pit and underground mining operations for the ultimate purpose of optimizing production blasts. Techniques in monitoring single borehole blasts using both pressure and vibration sensors to establish in-situ dynamic rock properties are outlined, including characterization of multiple borehole production blasts with regard to stress generation.Once field derived measurements are computer analyzed, they are channelled as input parallel to other data, such as the explosives thermochemical performance properties generated by a sophisticated computer program called ""HT-65"" into BLASPA . BLASPA, a blast simulation computer program, then couples these input with a mathematical model which defines the blasting processes. Aspects such as the blast geometry, explosive loads and distribution, hook-up, and costs are studied. The final output table gives specific blast performance or quality factors for each blast procedure. These results are then easily compared and rapidly optimized to achieve maximum performance at lowest blasting and drilling cost."

Jan 1, 1984