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By J. L. Collins

"This paper deals with the quantitative analysis of mine maintenance records. Based on a case study of dozer engine records, the author suggests an easy method of deriving useful information for managerial decisions in a step-by-step manner.More specifically, the paper deals with the following topics:• determination of the most economical replacement time,• determination of reliability characteristics,• determination of the number of replacements, and• determination of the number of spares.IntroductionThe mining industry collects a lot of information about every aspect of its activities, an example of which appears in Table I. In Table I , the distribution describes the operating hours at failure of 56 different dozer engines used in severe applications. Besides calculating an average and possibly a standard derivation from the data, little else is derived, at least from a statistical point-of-view.More information can be obtained from these records that could help management in the decision-making process.To illustrate this point, the sample data appearing in Table I will be analyzed in detail by making use of well-known concepts in reliability engineering.Distribution of DataTable I represents a distribution obtained from the recorded hours cumulated from the operators' time cards. The operating hours have been divided into fourteen classes for each 1000 hours of engine running, e.g . all engines scoring an operating time of between 1001 and 2000 hours formed a class , those scoring between 2001 and 3000 hours another one, etc. Generally, the class interval should be a multiple of the equipment preventive maintenance check period.The minimum acceptable sample size should be large enough to ensure that the score in each class interval is at least one. Ideally, the score for each class interval should be at least five so that a chi-square test could be carried out if necessary.The average life of an engine can be found by adding the products of the frequency and the class mark (mid-point) values. Therefore:"

Jan 1, 1987

By B. Fang

Electrochemical behavior of an X-80 pipeline steel, including frequency-sweep electrochemical-impedance spectroscopy (EIS), time-sweep EIS at a constant frequency and open-circuit potential (OCP) monitor, was investigated using four-point bending specimens subjected to a stress-corrosion cracking (SCC) test in a near-neutral pH environment, The capacitive loop became smaller with test duration, revealing an increase in the corrosion rate, The resistance obtained in the constant-frequency EIS test showed two regions, of which the region with a remarkable decrease in resistance transformed into a region of slow decrease, whereas the capacitance increased with test time indicating that iron dissolution was fast at first, and then a corrosion product or film formed and covered the surface, leading to the pitting formation.

Jan 1, 2005

Automation Defined ?Using self-operating equipment to reduce human exposure to the mining environment and routine or repetitive work.?-Atlas Copco Terminology: ?Manual Operation ?A vehicle being operated by a person ?in the cab?. ?Radio Remote Control (RRC) ?A vehicle being physically operated by a person through a Line Of Sight (LOS) or Video-Remote equipment. ?Tele-Remote Control ?A vehicle being physically operated by a person at an operator station which is not necessarily located near the vehicle?s working area. ?Autonomous Operation ?A vehicle under self control with the possibility of human supervision and override.

Oct 1, 2010

By D. Laguitton

"Mathematics, process theory, process practice and computer applications are the main disciplines that contribute to developing useful techniques for computer simulation of mineral and coal processing plants. As in any multidisciplinary effort, communication or transfer mechanisms must be developed to facilitate the flow of experience between participants of different backgrounds. These mechanisms include written reports, verbal communications, workshops and transfer of computer programs. The SPOC project at CANMET is devoted to computer simulation and as such has addressed, or will address in the near future, problems inherent to methodology transfer. The first major output of the project was the material balance program, MATBAL2, which has been acquired by over 30 organizations. Program documentation, industrial workshops and summer student programs have been used to effect the transfer. This experience is discussed and the future outlined.IntroductionComputer simulation has become a common tool in many different fields of human activity during the past two decades, as illustrated in Figure 1. The total number of articles abstracted in Chemical Abstracts under the general subject entry of “Simulation"" has been following a pseudo-exponential growth since 1972 and was approaching 5000 in 1980, whereas no such entry was even used prior to 1967. This represents over a dozen papers published daily on the subject and should continue to grow to higher figures. Still, progress toward accepting modelling and simulation in mineral and coal processing has been very slow. It will be shown later that this slow acceptance is a cause rather than a consequence of the limited success of the various attempts made so far to draw unambiguous benefits from simulation applications. The real cause of the difficulties in fully accepting the new methodology lies in the multidisciplinary aspect of modelling and simulation, which does not suit the traditionally conservative approach that prevails in designing and operating large and costly processing plants."

Jan 1, 1982

By Michael J. Sapko, Ellsworth R. Spencer, Frank J. Perzak

"The fire resistance of several mine conveyor belts is evaluated using a new belt-flammability apparatus developed by the U.S. Bureau of Mines. The test apparatus, experimental details and a calculated flammability index (FI) are described.The FI values are useful for ranking the fir e resistance of mine conveyor belts. Values are determined using parameters readily measured with thermocouples, high-temperature flow probes and a methane-oxygen torch, all of which are components of the Bureau's new test apparatus. The FI varies directly with the flame-spread rate and the rate of heat release during burning and varies inversely with the critical (minimum) ignitor energy output.The fire-resistance ranking of nine different belt types using this moderately scaled apparatus is compared with available full-scale data on belt fires. This comparison shows that the ranking based on the FI is consistent with the full-scale data.IntroductionFull-scale fire hazard evaluations of mine conveyor belts are not easily related to the properties usually measured in small-scale flammability tests. The inadequacy of small-scale belt fire tests has been demonstrated in works by Mitchell, Warner and Reinke.Mitchell and Warner showed that certain neoprene (NP) and polyvinyl chloride (PVC) belts, which had been approved by the Code of Federal Regulations 30 CFR 18.65, were nevertheless capable of propagating flame over their entire length when full-scale fire conditions were simulated. Comparable results were also observed by Reinke at the Tremonia experimental mine in Dortmund, West Germany, where all belts burned in full-scale tests even though they passed the small-scale tests. Only by reducing the severity of the full-scale test could these fire-resistant belts be grouped on a pass-fail basis."

Jan 1, 1982

By N. Ogbonna, D. G. Dixon

Although heap bioleaching has been recognized as an economic alternative for treating low grade mineral ores, the underlying physical, chemical and biological processes involved are complex. A detailed investigation into the dynamics of heap bioleaching processes has provided much insight into the underlying complexities, and has led to the development of a sophisticated modelling tool - HeapSim. This tool can be of great help in the design and operation of heap bioleaching processes. In this paper, the mathematical model implemented in HeapSim is examined. The model takes into account mineral kinetics, particle level effects, bacterial growth, oxidation and adsorption, gas absorption, pore diffusion, bulk advection, gas balance and heat conservation. Three case studies where the model has been applied are briefly discussed. Computational Analysis in Hydrometallurgy 35th Annual Hydrometallurgy Meeting held in conjunction with the 44th Annual Conference of Metallurgists of CIM Calgary, Alberta, Canada Edited by

Jan 1, 2005

By Robert B. Parsons

"In this period of improved metal prices and reported profits, valuable lessons should be recalled from the 1970s when a similar cycle lured the federal and provincial governments into thinking that they could grab bigger pieces of the pie without harming the minerals industry. It took years for the industry to recover from the damage inflicted by that unprecedented scramble for higher tax revenues. It is hoped that the current policy makers will have learned from the lessons of the seventies, and will realize that mining companies need to keep a reasonable share of profits realized during the good years in order to prepare for the inevitable downturn in the cycle.INTRODUCTION"", «. We have made clear to industry that super profits... will no longer be tolerated "".With that assertion, the Honourable David Barrett , Premier and Minister of Finance of the Province of British Columbia, announced the introduction of a new mining tax regime in his February 17, 1974 bud get papers . British Columbia producers would face a basic royalty and a royalty on so-called ""super profits"", resulting in some instances in tax rates exceeding 100070 of pre-tax profits.The ball started to roll. Mining tax changes knew no political or geo graphical boundary. On April 9, 1974, Ontario's Treasurer John White stated in his budget speech:""Increased demand by major industrialized countries has resulted in sharply higher metals prices and substantial wind fall gains for the mining industry in Ontario. With the prospective demand for minerals likely to sustain current price trends into the future, it is only fair that we secure for the people a higher return from our natural resources""."

Jan 1, 1989

By John H. Fowler

"Barytes is one of the major components of drilling fluids used in oil and gas well-drilling. This mineral's close association with the petroleum industry bestows it with a commodity status not enjoyed by many other industrial minerals. Approximately 85% of world barytes production is used as a weighting agent in oil and gas well drilling while the remaining 15% is consumed mainly in the manufacture of barium chemicals, glass and as a pigment, filler or extender.Barytes mining began in Nova Scotia around 1865 and has continued until the present. Currently there are three barytes producers in the province one exporting pharmaceutical-grade barium sulphate and the other two supplying drilling mud-grade barytes to the offshore. Several barytes exploration and development programs are underway with excellent possibilities that Nova Scotia deposits will supply a significantly larger share of the drilling mud-grade barytes used in east coast drilling programs.Currently there is renewed interest in barytes activities in Nova Scotia because of its use as a weighting agent in drilling flu ids used in offshore oil and gas drilling programs.This paper reviews the use of barytes by the well drilling industry; outlines the history of barytes mining in the province, progressing to present-day exploration, development and production activities underway in Nova Scotia; and concludes with the market potential for Nova Scotia barytes."

Jan 1, 1986

By Richard S. Allen

"The casual visitor is not apt to think of the Adirondacks as a one-time hive of mining and manufacturing activity. However, where there are mountains there are usually minerals and northern New York State is no exception.The Adirondacks are a rocky shield, a great stone cap pulled down over what is now northern New York. The bedrock consists of layered metamorphic rocks which were once sandstones or limestones on the bottom of a shallow sea that covered the region 1000 million years ago. The highlands are composed for the most part of the igneous rock anorthosite. Ancient earth upheavals at temperatures of at least 750°C mixed molten masses of anorthosite and the minerals it contained with the older metamorphic rock, resulting in deposits of iron-titanium oxide s, red garnet and other valuable minerals. Of these, the most readily recognizable was iron.The first hint of the existence of iron ore in the Adirondack Lake Champlain region of upper New York State seems to have come from a Swedish naturalist, Peter Kalm (1716-1769), who travelled through French Canada and visited the military outpost of Fort St. Frederic in 1749. In July of that year, Kalm wrote:""Among the kinds of sand which are found on the shores of Lake Champlain; one is black and the other garnet-colored... and they sparkle when the sun shines. All the grains of this sand without exception are attracted to the magnet, the uppermost or black sand being about a quarter inch deep...""Concerned primarily with the fur trade, the officers and men who occupied this remote bastion of La Belle France were apparently unaware of the industrial and commercial possibilities beneath their feet. No deposit of iron was then known to exist any closer than the Three River s area in Lower Canada."

Jan 1, 1983

By P. R. A. Andrews

"A sample of flotation feed from Bakertalc Inc., High water, Quebec was subjected to flotation evaluation to improve the recovery of talc. A number of alternative frother/collectors and depressants as well as flotation parameters including pH, conditioning time, frother/collector concentration and pulp density were assessed. In addition, the possibility of using a size coarser than that currently employed for flotation (95% minus 50 um) was investigated.As far as possible, a laboratory duplication of the present circuit arrangement was folio wed so as to minimize the cost of any changes. The best results obtained were a concentrate analyzing 95.96% acid insol for a recovery of 65.98% after four stages of cleaning. With recirculation of cleaner tailings, the recovery would be higher.The possibility of using an alternative method, based on the natural ability of talc to float unaided by a frother/collector, was briefly explored with encouraging results.IntroductionBakertalc lnc ., located in the eastern townships at Highwater, Quebec, Is approximately 140 km east of Montreal near the Vermont, U.S. border. Originally called Baker Mining and Milling Co. Ltd., it has produced pulverized talc products since 1938(1 ), although records show that talc was mined in the area as early as 1871(2). Feed to the mill originally was obtained from local deposits, but since 1952 the van Reet mine near south Bolton, approximately 25 km from Highwater, has been the source of ore .In 1957 a Raymond high -side roller mill was installed which enabled production of a greater range of talc products and, in 1960, new crushing equipment and a dryer were added. Other additions to the mill were the introduction of wet magnetic separation, although this was later discontinued, and flotation to produce high-grade talc concentrates."

Jan 1, 1985

By E. Lee Cameron

The old mine workings on four barite-fluorite veins of the Lake Ainslie district, Nova Scotia, were opened recently and channel sampled. The samples were then forwarded to the Ore Dressing Laboratories, Bureau of Mines, Ottawa, for chemical analyses. Following the analyses, the sample rejects were combined to form bulk samples, representing ore from each vein, for small-scale batch test work. Tonnage samples from the veins, for pilot mill testing, were submitted when requested by the Bureau. The results of the analyses on the channel samples showed that there are two grades of ore in the di strict, represented, for test purposes, by the Trout River vein and Johnson vein ores. Small-scale and pilot-plant test work was undertaken on both these ores. The Trout River ore is amenable co concentration but, because of the high-barite-co-fluorite-co-calcite ratio, a fluorite concentrate was not obtainable from the Johnson vein ore as received. However, Johnson ore blended in a 1 :1 ratio with Trout River ore gave a mill feed that was readily concentrated. The test work on these ores showed that the following concentrates are obtainable : (a) A barite concentrate, with a recovery of 85 to 95 per cent of the available barite, analysing 93 co 96 per cent BaS04, 4 co 6 per cent CaF,, and 0.5 co 2 per cent CaCO3. (b) A fluorite concentrate, with a recovery of 80 co 85 per cent of the available fluorite, analysing 94 to 97 per cent CaF, , 1 to 3 per cent BaSO., and 1 to 3 per cent CaCO3

Jan 1, 1945

By W. Gan

The interactions between bitumen and quartz sands in aqueous solutions were studied with the objective of recovering residual bitumen from Athabasca oil sands froth treatment tailings. It was observed that the presence of various multivalent metal cation (Fe3-, Fe2+, Mg2+,Ca2+, etc.) increased the mutual coagulation between quartz particles and oil or bitumen droplets within certain pH ranges. While the increased coagulation was detrimental to the recovery of the bitumen since it lowered the degree of bitumen liberation from sands, this effect could be reduced or eliminated by the addition of organic chemicals such as citric acid, oxalic acid and EDTA. Among these organic chemicals, citric acid was found particularly effective even at very low concentration.

Jan 1, 2006

By A. B. Szwilski

The paper outlines the factors taken into account for the selection of steel arch supports. The results are based on experience using the long wall system of coal mining where roadway closure can be extreme. Results of tests on scale-model steel arches and full-scale yield elements are also presented.

Jan 1, 1979

By John C. Loretto

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

Jan 1, 1982

By M. Fiset, D. Belley

"To better understand the wear process of various materials that may be used as blades on snow removal equipment, the first step is to evaluate the influence of the load applied and the moving speed on road wear rates of one type of steel and three types of polymers. While the behavior of steel conforms to Archard's law, wear rates of polymers increase to a power of ex of the load applied according to a model implying that the wear of these materials is due to fatigue. The wear rate of some of the polymers varies considerably in terms of speed, unlike the steel. The wear resistance of some of these polymers outclasses the steel tested as long as the speed is not too great. They, therefore, present interesting alternatives for snow removal on more fragile surfaces such as sidewalks and zone made of inter-block slabs.IntroductionSince the dawn of the Industrial Revolution, the massive use of machines has brought with it a number of different problems regarding wear. Snowplowing roads, parking lots and sidewalks is an activity that generates enormous expense in a country such as Canada. To better understand these wear processes and in the hope of stimulating new approaches designed to reduce the costs related to this sector of activity, this paper presents the behaviour of several materials (steel, polymer and rubber) as they wear on an asphalt-fines matrix surface lubricated with water. Also discussed is the effect of various parameters such as the load applied and speed."

Jan 1, 1990

By Burden of Occupational Cancer in Canada Project Team, Demers P. A., Kim J., Arrandale V. H., Jardine K.

"In 2012 diesel engine exhaust (DEE) was classified as a human carcinogen by the International Agency for Research on Cancer (IARC) and is one of the most common workplace carcinogens internationally. We estimate that approximately 2.4% of lung cancers (n=560) and a suspected 2.7% of bladder cancers (n=200) are attributable to occupational exposure to DEE annually in Canada. High levels of exposure to DEE in mining results in a disproportionate number of cancers in this sector (approximately 220 lung and 20 suspected bladder cancers annually). These could be prevented by reducing the number of workers exposed and level of exposure. KEYWORDS Bladder cancer, Diesel engine exhaust, Economic burden, Lung cancer, Mining, Occupational cancer, Prevention, Regulation INTRODUCTION Diesel engine exhaust is a complex mixture of gases and particulates containing known and suspected carcinogens such as benzene, polycyclic aromatic hydrocarbons (PAHs), and metals. Approximately 900,000 Canadians are exposed to diesel engine exhaust at work, making it the most prevalent occupational lung carcinogen in Canada (CAREX Canada). Diesel engine exhaust is recognized as one of the most common workplace carcinogens in the world, but its classification as a human carcinogen by the International Agency for Research on Cancer (IARC) was relatively recent. In 2012, after decades of mounting evidence, diesel engine exhaust was upgraded from a probable (IARC Group 2A) to a definite human carcinogen (IARC Group 1) (IARC, 2014). The IARC evaluation was based on strong evidence in humans for an increased risk of lung cancer, as well as strong evidence in animal studies. The key human evidence considered by IARC was from epidemiologic studies of workers in truck transportation, rail transportation, and mining industries, where the use of diesel engines is widespread. These studies provided strong sufficient evidence for an increased risk of lung cancer, as well as limited evidence for bladder cancer. The human studies used particulate matter, generally measured as elemental carbon (EC) or total carbon, as a surrogate for diesel engine exhaust to assess the risk associated with level of exposure. The animal studies reviewed by IARC showed sufficient evidence for cancer with exposure to whole diesel exhaust and the particulate matter fraction of diesel exhaust, but not for the gas phase components."

Jan 1, 2019

By Edgar Dernedde

Cryolitic melts at a temperature of about 960 °C are used in reduction cells to dissolve alumina and to produce primary aluminium. At these temperatures cryolitic melts with an acidic composition have a significant vapour pressure, which contributes substantially to the evolution of fluorides from these cells, The Antoine equation is commonly used for relating vapour pressure data of liquids at different temperatures, It is also applicable to cryolitic melts, Published equations have at least 20 numerical constants, in order to allow for the effects of melt composition. In the present work a simplified equation with only 12 numerical constants was developed and is applicable for multiple additions to molten cryolite up to 30 wt %, The simplified equation was compared with the published equations of Haupin & Kvande and Gustaysen & Ostvold using 472 vapour pressure data of cryolitic melts. Results showed that the simplified equation has the same accuracy as the published equations in the composition range of interest to industry.

Jan 1, 2004

By Unknown

With the present-day trend of rising labour costs and a lowering of production efficiency of workmen, it has become imperative that every effort be made to use manpower to the greatest advantage and to mechanize mining as much as possible. During the past few years this trend has gained much prominence in the Porcupine camp. In view of this, the executive of the Porcupine Branch considered that the Mechanical Movement of Muck would be a very timely subject for a Symposium. Accordingly a Committee was formed, with A. K. Douglass, Mine Superintendent for Delnite Mines, Ltd., as Chairman, and the Symposium was held in the Auditorium of the McIntyre Community Building, Schumacher, on March 25th last. Papers dealing with shovel loader and mechanical scraper operation at six of the larger mines of the camp were presented and discussed, and a tabulation was prepared giving data on the machines in operation at a total of eleven mines. The papers and tabulation, reproduced below, will doubtless be of considerable interest to operators of mines in all parts of Canada.

Jan 1, 1948

By J. W. Matousek

"More copper concentrates are treated in flash smelting furnaces than by any other process, and such furnaces are located in most of the world's major copper producing areas. Except for perhaps two furnaces treating chalcocite-type materials, little difference is seen between the grades of the concentrates being smelted. Within individual smelters, even less variation in feed grades is found. This is both accidental and intended. Many furnaces treat concentrates from captive ores, and these tend to be of relatively constant composition over long periods. Toll smelting operations blend concentrates to ensure delivery of feeds of fixed compositions to their furnaces to avoid upset conditions. Matte grades vary between flash smelting furnaces, but most commonly, these are the result of differences in operating practices rather than because of differences in concentrate grades. This paper reviews an industrial flash smelting test in which the copper content of the furnace feed was intentionally altered over a wide range. IntroductionExcept in a few copper mining regions of the world, the principal copper mineral is chalcopyrite (CuFeSz). This results in the almost universal production of concentrates containing 25070 to 30% copper (and similar amounts of iron and sulphur). Many operators of copper flash furnaces spend their entire metallurgical careers smelting concentrates of essentially fixed grades. This is true both of smelters treating concentrates from captive mines and those processing concentrates on a toll basis. From the production staff's point-of-view, the less variation in grades seen by the furnace, the better. Fixed analyses of concentrates and constant feed rates produce consistent quantities of matte at a consistent grade for processing by the converters. The result is, even in smelters treating a variety of concentrates, efforts are expended in sampling and blending to ensure feeds of relatively uniform compositions being sent to the furnaces."

Jan 1, 1993

By S. Qian

Galvanic corrosion is a potentially major concern associated with the application of stainless steel reinforcement which is in direct (electrical) contact with carbon steel reinforcement in concrete structures. Judicious use of stainless steel rebar in both new construction and rehabilitation of older structures is a viable, cost-effective option for extending service life and reducing maintenance costs. Questions, however, had arisen about the possibility of increased corrosion due to galvanic effects. This paper investigates the galvanic-coupling behaviours of three different types of stainless steel and carbon steel. Tests were performed both in electrochemical cells and with specimens in concrete inside an environmental chamber. The results show that oxygen reduction on stainless steel is the rate-determining factor for galvanic coupling of these two metals. It is much lower than that of passive carbon steel. As a result, the galvanic coupling of stainless steel with carbon steel will not increase the risk of corrosion of carbon steel reinforcement.

Jan 1, 2005