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By A. C. Headon, K. W. Lam, D. P. Dautovich

"Microbiological activities affecting the performance of materials have been encountered in diverse situations within Ontario Hydro. Case histories of bacterial problems which are presented include ground rod corrosion at transformer stations, corrosion of a bare steel cooling water intake structure in Lake Huron and corrosion of steel components in a nuclear generation station vacuum building. Possible microbiological activities which may affect the corrosion behaviour of containers for the disposal of nuclear fuel waste in the future are discussed, as are bacterial actions suspected of causing an odour problem in residential water heaters.IntroductionBacteria are ubiquitous. Except by use of sterilization methods, bacteria -free environments are no t possible to find. Bacteria lie dormant in hostile environments, spread easily through air and water currents and reproduce rapidly under favourable conditions. Although different types of bacteria have different preferable conditions for growth, they are highly adaptive and in general, whenever there is a source of water and carbon (carbon dioxide or organic matter), there will be bacterial activities . These activities often induce or enhance costly metallic corrosion in industries and water odour problems in rural water supplies . Underground structures and systems in contact with natural water or water containing organic matter are most susceptible to bacterial attack.The types of metal-degrading bacteria , their characteristics and the conditions for growth have been reviewed extensively in the literature(1,2,3). There are several often encountered groups of bacteria which, through their metabolic processes, may lead to the degradation of metals. A large variety of bacteria produce corrosive in organic or organic acids as waste, such as the well known formation of sulphuric ac id by aerobic sulphur oxidizers . Anaerobic sulphate reducers produce hydrogen sulphide which is corrosive and has an obnoxious smell, slime-forming bacteria from slime which shelters sulphate reducers and iron bacteria oxidize ferrous to ferric ion which precipitates as hydrated oxides creating oxygen concentration cells . The following are bacterial problems encountered in Ontario Hydro. Although the number of recognized cases has been few, they show the diversity of location and environment where bacterial problems could arise. These include ground rod corrosion at transformer stations, corrosion of bare steel in a water intake structure, corrosion of steel in a nuclear generation station vacuum building and an odour problem in residential hot water tanks. In addition, possible bacterial- enhanced corrosion in containers for future disposal of nuclear fuel wastes are also discussed."

Jan 1, 1984

By Sukumar Bandopadhyay, Arunapuram Sundararajan

"For the last three decades, the application of network planning has provided a basis for a formal and general approach to the discipline of project management. For fixed activity duration, a very simple algorithm commonly known as critical path method (CPM), gives the length of time required for the total project as well as indicates the activities which are vital to the completion of a project. Project Evaluation Review Techniques (PER T) on the other hand, generalize the above approach to recognize uncertainty in the activity durations by allowing them to be random variables. One of the misleading aspects of current "" PER T"" solution method is, however, the implication that there is a unique critical path. In general, any number of paths could be critical, depending on the particular realization of the random activity durations that actually occur. In this case, simulation can be utilized to estimate completion time of a project.In this paper, the concept of criticality indexing is discussed, and a simulation model application which defines the critical path based on the criticality indexing concept, to a longwall development - extraction network, is presented. The model also provides suitable scheduling of resources based on the resource constraints and smooth s out period-t o-period assignments. IntroductionThe successful management of large-scale projects require careful planning, scheduling , and coordinating numerous interrelated activities. To aid in these task s, formal procedures based on the networks and network techniques (variously called PERT or CPM) were developed. In its original form the completion time for individual activities of a project was assumed fixed and known in advance: this in turn led to the familiar algorithms for computing the critical path, earliest start time, slack, and so forth. The unreality of such an assumption is, of course , apparent in many contexts. Consequently, attempts were made to introduce probalistic activity completion times, allowing representation of the stochastic nature of most projects."

Jan 1, 1987

By V. W. Shtenko, B. J. Ennis, P. H. Bridge

"The northeastern region of British Columbia contains large quantities of high-quality metallurgical coal. To market the coal, it was necessary to provide the required infrastructure which included rail access. This paper presents the role of the British Columbia Railway in the northeast coal development.In 1976, B.C. Railway undertook to study two main routes, one originating at Chetwynd and the other at Anzac, both located on the main line, north of Prince George. The routes studied are briefly described, detailing the methodology and engineering analysis carried out to permit the selection of a single route that would be the most cost effective, taking into consideration the construction, maintenance and operating costs. The operating parameters, track and grade standards, anticipated tonnage, construction costs and the final route selected are also presented.Pre-engineering analysis and studies of the route selected originating at Anzac, known as Tumbler Ridge Branch Line, and which commenced in 1977, were concluded in 1978. New mapping was developed to a scale of 1:2000 with good vertical and horizontal control. Based on the mapping data, terrain analysis, and designs developed, an estimate of construction costs and schedule of work was developed.Authority to proceed with the final design and construction was provided in December 1980, with the first shipment scheduled for December I, 1983. Final designs of all structures are discussed, including schedules, cost to completion, and control systems utilized. The decision to electrify the Tumbler Ridge Branch Line and related topics are discussed, with a brief description of train operations. The present status of the project is also presented."

Jan 1, 1983

By James Logan

BC Alkaline CuBC Cu--Au PorphyriesAu Porphyries ?Formed over narrow time interval ~205 Ma ?from silica deficientvsalkali-enriched magmas ?At shallowdepths ?Structuralcontrol ?Cu-Au-Ag, trace Mo ?Oxidized system anhydrite, magnetite ?Multipleintrusions & multiplemineralized centres

May 1, 2006

By Malcolm Scoble

Process Technologies Suitable for Application Underground Design Criteria - coarse particle technologies - compact, robust, flexible - waste products suitable for use as backfill Process technologies identified: - Optical/conductivity sorting - Dense media separation - Coarse-particle flotation Process technologies supported by compact & efficient comminution stages Mineralogical evaluation to select process & estimate Performance Further Work U/G Plant Layout & Excavation Modelling Evaluate scenario at increasing depth Establish properties of waste as backfill Model impact of improved backfill quality Evaluate further case studies Evaluate further Environmental Health and Safety Issues Model impact of system development on inventory of national mineral reserves Conclusions Technologies exist for integrated underground mining and processing systems These technologies to be successfully integrated into underground mining system Positive economic and environmental benefits Technical issues to be resolved at depth System Development path identified

May 1, 2004

By Lar Liljeblad

"As demands upon the earth's natural resources continue to grow, exploration companies, mining organizations and others face the problem of the need to tackle increasingly more difficult strata to open up new reserves. Innovations in materials technology and tool design have steadily improved this capability, but none perhaps so drastically as a recently introduced cemented carbide in which tool wear resistance and/or toughness can be tailored precisely to the user's drilling needs.Introduction Until about forty years ago, the bulk of rock-drilling operations had to be carried out with hardened steels. Short life between re-grinds was common especially in abrasive rock formations. Shortly after World War II, Sandvik, Sweden, pioneered the development of sintered (cemented) carbide-tipped steel tools as a means of improving drill tool life. The new material was a composite of tungsten carbide and cobalt, the latter acting as a 'cement' to bind the wear-resistant carbide grains together, and the composite, in turn, was brazed to the steel. The immediate effect was a 100-fold increase in the service life of the tool.Intractable ProblemsWhile the carbide-tipped tools served the mining and quarrying industries admirably there were, nonetheless, some seemingly intractable limitations. The greater the wear resistance of the material - the quality for which it is selected - the more brittle it is. Also, rocks vary widely in hardness and abrasiveness and no single tool, either in terms of material or shape, meets every need. Specifically, for fast penetration of non-abrasive rock, toughness must be combined with a relatively sharp tool prome. Highly abrasive rock, on the other hand, demands a substantially broad area of extremely wear-resistant material on the tool if long bit life is to be assured. Between these extremes there are innumerable variations in rock"

Jan 1, 1991

By V. J. Hucka, J. H. Tu

"A computer model has been developed for evaluating the performance of truck and shovel operations in an open-pit mine. The data required for describing the haulage network are simplified and shift startup and ending procedures specific to any given mine can be incorporated into the model readily . The model uses a FORTRAN-based simulation language SLAM and can be tailored to the conditions and practices of a particular mine.The model is used to analyze truck and shovel operations, evaluate different haulage layouts in the planning stage, or compare the expected performance of alternative truck dispatching systems.Stochastic simulation is used to model the random variation in time required f or the individual activities. This gives a more realistic representation of the processes under study. Simulation runs show good agreement with actual performance. The model is especially useful for examining alternatives in equipment acquisition , haulroad design, truck-shovel allocation and dispatching methods. The results of such simulations provide a sound basis f or making major management decisions.IntroductionTruck haul age is widely used in open-pit mining operations. It is also the largest cost item in the operating costs of an openpit mine, in some cases accounting for an estimated 50% of operating costs(1) , Truck replacements, which are necessary from time to time, involve large amounts of cap ital. Increasing depth of mining and consequent increase in stripping ratios require additional capital investment in the truck-shovel fleet. The sharp rise in energy costs over the last decade has also contibuted significantly to an increase in truck fleet operating costs . All these factors have led mine operators to search for ways to improve the effectiveness of the truck-shovel fleet, in order to lower costs and maintain a profitable operation in the face of declining markets and increasing world wide competition.Control of truck haulage in an open-pit mine is usually done in one of two ways."

Jan 1, 1985

By D. A. Nelson, Wedding. R. E.

"A planned production increase of 1.25 million tonnes per year at Domtar's salt mine in Goderich, Ontario required an increase in the underground mine ventilation system from 320,000 to 700,000 scfm, The design of the expanded facility included the addition of a 22-foot-diameter shaft to augment the existing production and service shafts.A preliminary review of the ventilation requirement s indicated that in order to pr ovide good economic design for the expanded system, a comprehensive ventilation survey of the existing system was required. The survey was completed in the latter part of 1980, and subsequent engineering design and equipment selection proceeded throughout 1981.This paper presents the methods used to carry out the survey. Particular attention is given to the numerous challenges presented in determining air flows in the large 45-ftwide by 43-ft-high airways. Emphasis is placed on practical field survey techniques.A mathematical model of the ventilation system using a computer program is described, and the application of this program to provide design data and assist in equipment selection is discussed. Economic sizing of airways and fan selection are analyzed considering horsepower and operating costs.IntroductionThe Goderich Mine of Sifto Salt Division, Domtar Inc., is located on the eastern shore of Lake Huron in the town of Goderich, Ontario, and has been operating since November 1959. The salt is extracted by a modified room-and-pillar method, and the workings advance at a rate of 1.5 miles per year by undercutting, drilling and blasting. The surface mine area consists of a 12-acre site in the Goderich harbour, at the mouth of the Maitland River, and the underground property consists of approximately 2,700 acres lying mainly under Lake Huron."

Jan 1, 1983

By P. K. Kaiser, S. M. Maloney, S. P. Singh

"Corrosion of underground support measures constitutes a concern to industry in both safety and economic terms. It also represents a potential market for corrosion resistant materials such as stainless steel.In order to assess the market potential for a stainless steel friction rock bolt, a review of current corrosion processes and remedial or preventative measures in the underground environment was undertaken. This was supplemented by distribution to industry of a detailed questionnaire, concerning the magnitude and extent of support corrosion and the costs of current support measures, and by visits to selected sites. Following data synthesis, support costs were established and the economic benefit of stainless steel rock bolts evaluated.Stainless steel rock bolts can be an effective cost reducing measure in unscreened areas requiring frequent reconditioning. Their benefit is rapidly diminished, however, if only partial reconditioning is required, the reconditioning interval is long or if screening is required.While most industry personnel are receptive to the application of stainless steel support measures, the localization of corrosion problems and the potential high cost of this type of support are barriers to its widespread implementation. They have potential for use in extreme environments. However, this relatively small market may not be economically viable.IntroductionFriction rock bolts are the simplest of all interior rock fixtures. The friction resistance to sliding of the rock on the bolt is generated by a radial pressure against the borehole wall over the length of the bolt. Two types of friction rock bolts are currently marketed, the Split Set and the Swellex.Unlike conventional point anchor bolts, friction rock stabilizers may move relative to the rock strata and maintain their capacity even if rock shifts, a condition that sometimes loosens or breaks conventional bolts. Ease of installation, effectiveness in jointed as well as weaker rock, and the possibility of having relatively long bolts are a few of the many advantages which generate considerable interest in the application of friction rock bolts (Wijk and Skogberg, 1982). However, due to their thin-walled construction and large surface area, frictional rock stabilizers are more susceptible than conventional bolts to damage by corrosion. For this reason, they are normally not recommended for long-term use (Jolly and Neumeier, 1987).In light of the above discussion; the Nickel Development Institute commissioned a study by the Geomechanics Research Centre with the objective of generating a credible database for the assessment of the feasibility of a stainless steel friction bolt system in corrosive ground and mine environments."

Jan 1, 1990

By H. Sahay

"DISCLAIMER NOTICEThe views and conclusions contained in this presentation are those of the author and should not be interpreted as necessarily representing the official policies or recommendations of the Department of Mines and Energy, Government of Newfoundland and Labrador. ABSTRACTThis paper describes the main testing procedures that should be carried out to evaluate the capacity and capability of the service brakes on the large-size diesel-electric trucks now in common use at open-pit mining operations. Brake testing programs in general are described, and then consideration is given to different techniques of service brake testing, brake performance evaluation, braking energy and typical performance characteristics.IntroductionThe first diesel-electric truck with a capacity of about 85 tons was introduced in 1963 by Unit Rig and Equipment Company of Tulsa in cooperation with General Electric Company, who successfully developed and supplied the most important component- motorized wheels. Since then, its popularity and numbers have continued to grow, and now more than 3700 such units are in operation in mines around the world. In Canada alone, their number is more than 700, including about 150 in the Province of Newfoundland and Labrador. Similarly, their size has also grown from that initial capacity of 85 tons to 350 tons.Although the introduction of the electric trucks proved to be invariably economical, their indiscriminate use was not without severe consequences. Many runaways and even fatalities occurred when the dynamic retarder failed while the truck was travelling loaded down severe grades. The service brakes in such cases proved incapable of stopping runaway trucks, mainly due to their limited capability and the fading caused by excessive heat produced during the act of braking itself. This eventually led the various governments, the open-pit operators and the manufacturers to seriously question the braking capability as well as function of both service brakes and dynamic retarders. Extensive testing"

Jan 1, 1980

By O. Neves, C. G. González Beca, M. C. Sol Pereira, H. Sousa Vale, R. A. Guedes de Carvalho, M. N. Sampaio

"As sulphide ores are usually concentrated by flotation , the material is very finely ground <37um), wet and impregnated with the chemicals used in flotation. These conditions are favourable to the development ofchemical reactions which are largely influenced by atmospheric conditions (temperature, humidity, wind, etc.) as well as by the geometry of the piles.Physical and chemical properties of a chalcopyrite concentrate were determined by laboratory tests. The knowledge of these properties was considered necessary in order to establish a correct design of the storage and handling operations of the sulphide ore concentrates obtained by flotation.The properties studied in this work were: transportable moisture limit, flowability, effects of vibration, hygroscopicity, ""caking"", chemical alterations by humidity, oxidation and self-heating (auto-ignition, dry and wet oxidation, self-heating by humidification and its prevention).INTRODUCTIONIn order that the handling and the transport of a powdered material may be carried out correctly, it is necessary to know certain physico-chemical characteristics. Transportable moisture limit (TML), apparent density (both aerated and compacted), compressibility, angle of repose, angle of spatula, cohesion and angle of slide(l-4) are characteristics (among the flowability parameters) worth knowing.Moisture content of the powdered material is fundamental, because if this is too low heavy losses will occur when the product&apos;s particle size is very small, if it is too high, separations between solid and liquid phases may occur. In the latter case, the centre of gravity of the system may change suddenly and cause accidents, mainly if transport is by sea or by river."

Jan 1, 1989

By G. M. Ritcey, A. W. Ashbrook

"This paper summarizes the optimum leach conditions for each Of several cobalt-containing arsenical feed materials, describes the solution treatment prior to purification of cobalt recovery, and discusses the plant operation on one feed as well as the treatment of effluents.IntroductionDuring the period 1962-1964, when the demand for uranium was low, Eldorado Mining and Refining Limited (Eldorado Nuclear Limited) made a decision to undertake a three-year diversification program. One area chosen in this program was that concerned with the processing of cobalt-nickel materials. Many such materials were evaluated over the three-year period, ranging from tailings, residues, ores, concentrates and speiss to metal scrap. Cobalt feed materials, on which much of the effort was concentrated, were those containing arsenic together with other metals such as silver, copper, nickel and iron. This paper describes the treatment of arsenic-bearing feed materials (ranging from 0.3 to 570/0 As) and the subsequent purification stages required before the separation and recovery of high-purity cobalt. Because of the current interest in treating cobalt ores, it seemed appropriate that the information on the treatment of various cobalt feeds should now be made available . Although a large amount of data were generated during the research and process development program, a complete scientific correlation and understanding could not be achieved. Nevertheless, the data may provide a guide to others involved in processing not only cobalt, but other arsenical ores."

Jan 1, 1981

By Song Mao, Local Joint Engineering Lab of Efficient Util of Dominant Mineral Resources from Karst Regions, Guizhou Key Lab of Comprehensive Utilization of Non-metallic Mineral Resource, Xianhai Li, Qin Zhang, unjian Ye, Guizhou University, Wei Cheng, Zhihong Liu

"Phosphate tailing is a kind of industrial waste that emitted from separation processing of phosphate ores, which is usually discarged to the tailing pond without treatment. Recovery of phosphorus from tailings is of great significance for comprehensive utilization of phosphorus resource. Chemical composition of a micro-fine cryptocrystalline phosphate tailing was investigated by X Ray Fluorescence (XRF) and Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES), and mineral composition and occurrence of harmful elements were analyzed by optical microscope and Scanning Electron Microscope (SEM), X ray Energy Dispersive Spectrometer (X-ray EDS) and Mineral liberation Analyzer (MLA). On the basis of above, effects of those on mineral processing for phosphate tailing was analyzed. Chemical analysis results in combination with microscopy indicated that there is a certain amount of iron and aluminum and it should focus on the removal of them in separation processing. The cryptocrystalline structure, especially the micro banding structure and micro porphyritic structure indicated that there is quite amount of phosphate in fine particles and it should recovery the phosphorus as much as possible when designing the flotation technology for this difficult separation fine phosphate tailing. This study can provide theoretical guide for efficient phosphorus recovery of from fine phosphate tailing by flotation.INTRODUCTIONPhosphate rocks are vital nonrenewable resources and are essential components in agricultural fertilizers and phosphorous-based chemicals (Gharabaghi et al., 2009). About 95% of the phosphate produced around the world is consumed in the fertilizer industry (page 60 Abdel-Zaher, 2008; Jasinski, 2007). Froth flotation, a solid wettability based separation process is widely used in separation of phosphate rock and shown to be effective (Yehia et al., 1990; Singh et al., 1992; Elgillani and Abouzeid, 1993; Al-Fariss et al., 2013) .Poor selectivity and low recovery for micro-fine particles are hard issues in flotation of middle-low grade phosphate ore because Phosphate resources is becoming poor, fine and complex as the rich ores run out since the 1970s. The rapid depletion of high grade ores forces minerals industry to process low grade ores where finer grinding is required to achieve required liberation of the values, making the fine particle flotation inevitable. the performance of conventional flotation deteriorates rapidly as particle size decreases to below 10-20 µm, depending on the density of the particles (Feng and Aldrich, 1999). To date, fine particle flotation is still considered to be a challenge in mineral processing (Li et al., 2015) ."

Jan 1, 2016

By P. R. A. Andrews

"Graphite is one of the most versatile of non-metallic minerals because of its diversified properties, for example: it is unctuous; it marks readily; burns slowly; is almost chemically inert; is flexible over a large temperature range; is a good conductor of heat and electricity; is hydrophobic; has a negative temperature coefficient of resistivity; has excellent weathering properties; tends to emulsify with water-in-oil; is readily soluble in iron; and after oxidative treatment, can exfoliate like vermiculite. These properties give rise to its major uses in lubrication, refractories, marking instruments, electrical products and paints.Flake graphite is the variety which commonly occurs in Canada; the provinces of Ontario and Quebec contain the deposits of economic significance, although graphite occurs in other provinces. The beneficiation of graphite has been the subject of many investigations at CANMET, thus reflecting graphite &apos;s importance as an industrial mineral. Thirty-eight studies relating to various aspects of beneficiation were conducted between 1918and 1989anda review of some of the more important studies is presented. The information includes mineralogy, beneficiation methods and results; flotation parameters and reagent concentration data are presented in tabular form. By so arranging the principal data, the research worker and production metallurgist will be assisted in the evaluation of graphite ores from a variety of origins."

Jan 1, 1992

By W. F. Giuvlore, E. Mcroberts, T. S. Golosinski

"The rising demand for Canadian coal and depletion of shallow deposits, most suitable for surface mining, result in rapidly increasing volume of waste materials which have to be moved by the coal mining industry. While at present this challenge is being successfully met using conventional mining methods, in the future, innovative methods must be considered if Canadian coal is to remain competitive.The need for more efficient mining methods is also faced by the oil sands industry to assure competitiveness of the synthetic oil price.A look at the world mining practice indicates that large volumes of material can be economically mined and moved by the continuous mining systems comprising bucket-wheel excavators, belt conveyors and stackers. To assess the state of art and applicability of this mining method to Canadian conditions, the field trip was organized by the Department of Mining Engineering o f the University of Alberta, to several typical mining operations in Europe. It is in Europe where the continuous mining methods were developed and are almost exclusively used in large-scale surface mining."

Jan 1, 1984

By Barry James

"This paper discusses past and current energy use patterns in the mining and manufacturing sectors of the industrial minerals industry. Information is presented on the primary energy input types as purchased by the industry, the quality and form of the energy actually required by the various production processes, and the residual form of this energy, either embodied in the product or rejected in gaseous and liquid waste heat streams. With the continuing concerns about the availability of energy combined with the rapidly increasing cost of energy as a production input, the reduction of energy usage through improved efficiency will undoubtedly be an increasing priority for the industry during the 1980s. Reduced energy consumption through investment to improve energy efficiency appears to be advantageous from both the corporate and national perspectives.IntroductionEnergy, like labour and materials, is one of the basic production input s to the various mining, processing and manufacturing production stages in the industrial minerals industry. Energy costs, as a percentage of total production costs, have been well above the average for industry in Canada, accounting for more than 50 cents out of every dollar in the most extreme cases. Consequently, energy has always been a relatively important management concern in the industrial minerals industry.The energy supply and price situation in Canada and internationally has been changing rapidly since 1973, following a long period characterized by declining real energy prices and an abundance and wide choice of energy supplies. It is generally accepted that energy prices will continue to increase rapidly, and that there will be uncertainties about the long-term continuity of supply of some energy types. In essence, a period of relative stability has been replaced by a period of relative uncertainty. In such a changing situation, a reassessment of the role of energy as a production input is appropriate.The following sections outline some of the effects of the changing energy scene on the industrial minerals industry. These effects are dealt with primarily in terms of energy costs, because, in most circumstances, a change in the cost of energy as a production input is the end result of both energy price and energy supply changes."

Jan 1, 1981

By Yve Potvin, Fabien Miller, Deni Jacob

"The potential benefits of measuring the volume of excavated open stope are enormous. By comparing the actual excavation of the orebody contour, it is possible to determine the “real"" amount of mining dilution, as well as the ore left in place. Noranda Technology Centre (NTC) has developed a stope survey system that allows for rapid and efficency measurement of underground excavation volumes. The system comprises a commercial laser (EDM), a set of lightweight rigid rods, an automated scanning device, a hand-held data logger and Autocad-based software for volume calculation and drawing manipulations. This system is an invaluable tool for the optimization of mining practices and could also be used for the delineation of caving areas. IntroductionDilution is the most common and devastating mine disease. In some instance s it could systematically cripple the profitability of an operation, and in more extreme cases, it could become a terminal disease. The Northern Miner Journal (1988) reported that many operations have closed because of uncontrolled dilution, before they even completed their first year of production. Other studies (Pakalnis, 1986) have shown that approximately 40% of all underground operations have more than 20% dilution. Considering that every ton of dilution costs in the neighbourhood of $25, the total direct cost of dilution to the Canadian mining industry may easily exceed one hundred million dollars per year.The dilution problem has been a major concern to Noranda Minerals for some time and in 1984 a comprehensive geomechanics research program was created at the Noranda Technology Centre (NTC) in Pointe-Claire, Quebec. New empirical stope dimensioning techniques, improved cable bolting techniques and sophisticated ground control instrumentation projects (among others) contributed to improve the situation at Noranda.A new tool which can have a very significant impact on the ""war"" against dilution is being developed by the Noranda Technology Centre. The laser stope survey system allows for a rapid, precise and efficient measurement of underground excavation volumes. By comparing the excavation planned with the volume excavated, it becomes possible to determine the ""real"" amount of mining dilution as well as the amount of ore left in place. This system may also allow for early detection of a dilution problem. As with other diseases, early detection provides the best chance for a fast and total recovery."

Jan 1, 1992

By E. O. Reinbold, J. H. Johnson, D. E. Keski-Hynnila

A field laboratory for use in monitoring underground mine air quality has been developed and proven in underground service. The laboratory includes two separate monitoring systems and data analysis computer programs. One is the Mine Air Monitoring Laboratory (MAML). This is an enclosed trailer-mounted laboratory capable of monitoring CO2, CO, NO, NO2 particulate matter, S02, NH3, temperature and air velocity in the mine drift. The MAML can be up to 1000 feet away from the area being monitored. The second system is the vehicle data system, mounted on the load-haul-dump (LHD) vehicle, which monitors engine speed, engine fuel rack position, exhaust gas temperature, ambient temperature, vehicle speed, CO2 concentration near the operators&apos; breathing zone and the mode of operation of the vehicle. The two computer data analysis programs and the two field instrument systems comprise a complete Mine Air Quality Laboratory (MAQL) for underground pollutant studies. Data from the systems have been used for studying vehicle duty cycles, ventilation systems, exhaust after-treatment devices, vehicle exhaust system design and portable instrumentation. Descriptions of the laboratory are presented along with a summary of some of the experiments performed. The capabilities of the lab are discussed, along with future potential uses.

Jan 1, 1981

By Robert B. Parsons

"The Department of Finance introduced draft amendments to the resource allowance regulations on July 23, 1992 that effectively nullify the decision in the Gulf Canada Limited case. Prior to the amendments it appeared that only ""directly"" related general and administrative, capital cost allowance and scientific research expenditures had to be deducted from resource profits. Now ancillary expenditures are required to be deducted. Consequently, the ability of taxpayers to claim the resource allowance is curtailed.IntroductionOn October 25, 1990 it was almost certain that taxable mines were going to get a break. The Federal Court-Trial Division had just decided in Gulf Canada Limited&apos;s favour to allow it to claim resource related tax benefits larger than what Revenue Canada evidently wished. Revenue Canada appealed first to the Federal Court of Appeal and then to the Supreme Court of Canada. On January 10, 1992 the Federal Court of Appeal agreed with the Federal Court decision and on July 2, 1992the Supreme Court declined to hear any further appeal. A mere three weeks later, on July 23, 1992, the Department of Finance issued draft ""clarifying"" measures to amend the calculation of the resource allowance. These measures effectively nullify the benefits that arose under the decisions of the Federal Court."

Jan 1, 1992

By Randolph A. Pax, Brian Cornish

The operation of grinding mills in an ore processing circuit is supported by monitoring the input and output variables. These can include the feed ore size distributions, ore feed and water addition rates. The outputs can include the discharge undersize density, oversize tonnage rate and the P80 of the discharge. The grinding mill performance is judged by the power draw, recycle rates and discharge grind size. Conditions inside the mill are inferred from loads cells or bearing pressures and past histories. An overall noise value is sometimes used to evaluate the load as well as the occurrence of excessive impacting of steel balls onto the liners/lifters of the mill. This paper presents results of the internal behaviour of a mill using non-contact stationary microphones located close to the mill outer shell (Pax, 2012). The noise generated by a mill can be attributed to a number of events that occur inside these mills and suitably analysed can provide real-time determinations of in-mill behaviour and can provide powerful insights into the operation of the primary comminution tumbling mills. The acoustically determined signals including a specific 'steel' signal, water hold-up, integrated area together with a classification of impact events. Specific results from case studies will show information of the trajectories inside a mill, steel to rock ratio as well as rheology effects. By incorporating a self-consistent understanding methodology for the in-mill processes from an array of microphones, the information can be used to diagnose the dynamic conditions inside a mill.

Jan 1, 2016