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By L. E. Djingheuzian

Introduction Cylindrical grinding mills have been used for a long time, but during many years of testing no methods were established that gave consistent results. The work by both scientific investigators and operators led very often to contradictory conclusions, and each millman was very much 'on his own' when trying to find the limits for working of his ball-mills. Fred C. Bond, in the introduction to his paper on Wear and Size Distribution of Grinding Balls, freely states that the mathematical immaturity of the grinding process "is the cause of many inefficient designs and installations as well as of much poorly oriented experimental work", and evidently he sees the solution of all our grinding problems in the discovery of the fundamental laws "which can change the empirical art into a mathematically exact science". While the writer is in complete agreement with Mr. Bond that grinding is governed by fundamental laws which can be expressed by mathematical formulae, there are so many variables in grinding, all interwoven with each other and mutually influencing each other, that the coalescing and merging of all these variables into a harmonious mathematical whole appears to be a homeric job. However, a light appeared on the horizon when it was proposed that power be used as an index of the grinding operation. It is pertinent to quote Gow, Guggenheim, Campbell, and Coghill from their paper on Ball Milling, in which they say: "Much of the past literature devoted to the subject has been concerned with the Kick-Rittinger dispute over evaluating grinding, or with dissertations on ball paths and the closely allied impact versus attrition hypotheses or with the exclusive consideration of certain specific variables, such as mill speed or circulating load, irrespectve of the other factors in operation. Such subjects may be dismissed with but little discussion in what may be called, by comparison a new philosophy in the stud of ball milling. Briefly this 'new philosophy' consists ' of using power as an index of the mill operation, and investigating grinding from the standpoint of set and induced variables with emphasis on the latter". But it is safe to assume that it was the work by E.W. Davis, H. E. T. Haultain, F. C. Dyer, A: M. Gaudin, J. Gross, S. R. Zimmerley, and others, that cleared the path for the authors of Ball Milling and induced them and A. W. Fahrenwald to look farther afield and thus to establish a far-reaching relationship between the power and capacity and the diameter of the ball-mills.

Jan 1, 1949

By M. Pearson, W. Bristowe, A. Hanson

"There's no such thing as quality assurance; only quality control ... by inspection. "(1) A common misunderstanding in the procurement and construction of custom designed, fabricated pressure vessels and piping systems is that quality assurance can be achieved by simply referencing codes, standards, ISO 9002, QMS or other such programs in the contract documents. In the authors' experience, nothing could be further from the truth, not detrimental to the performance of the equipment than the exclusion of inspection activities and reliance upon warranties and "fit-for-purpose" clauses. Likewise, the expectation that fabricators, suppliers, or third party inspectors can provide such assurances is also unrealistic where they have limited knowledge of the process, material selection criteria, or limited technical resources. The development and successful execution of a quality assurance program is a collaborative effort by engineers, designers, material suppliers, equipment fabricators, and field inspectors with the full understanding and support of the end user.This paper presents an outline of the quality control activities undertaken by the authors for several recently completed and on-going hydrometallurgical projects. The activities include: prequalification of fabricators and sub-vendors, shop audits, material validation testing, material source control and verification, positive material identification of weld metal overlay, specialised welding inspection, contamination control for titanium and titanium-clad fabrication, eddy current and mass spectrometer (helium) leak testing of shell-and-tube heat exchangers, hot cycle testing of titanium clad equipment, tolerance verification for refractory lined equipment, final inspection and cleaning.

Jan 1, 2004

By Jolanta Olkowska-Oetzel

Reactions of gold?phosphino complexes [(AuX)(PR3)] (X= Cl, Br, I; R = organic rest) with Se(SiMe3)2 lead to the formation of gold complexes with chalcogenide bridges. The reaction of the complex Ph3PAuCl and tBuSe(SiMe3) gives the cluster [Au5Se2(PPh3)4]Cl 1. The in situ preparation of the complex [(AuCl)2dpph] (dpph = Ph2P(CH2)6PPh2) by reaction of dpph with Me2SAuCl, and subsequent reaction with Se(SiMe3)2 leads to the formation of [(Au3Se)2(dpph)3]Cl2 2. Reactions of the gold(I) complex [(AuCl)2dpppe], (dpppe = Ph2P(CH2)5PPh2) with Se(SiMe3)2 and InCl3 in different molar ratios lead to the formation of [Au10Se4(dpppe)4]InCl5 3 and [Au4(SeInCl3)2(dpppe)2] 4. The reaction of [(AuCl)2dpph] with Te(SiMe3)2 and GaCl3 produces the isostructural cluster compound [Au4(TeGaCl3)2(dpph)2] 5. From the reaction of Se(SiMe3)2 with [(AuCl)2dppe] (dppe = Ph2P(CH2)2PPh2) and InCl3 [Au8Se4In(dppe)4](InCl4)3 6 can be isolated. The structures of 1 - 6 were determined by X?ray diffraction.

Oct 1, 2003

By Shuo Zhang, Wenying Liu

"In dump leaching, the efficiency of metal extraction from ores is strongly influenced by the mechanisms of fluid flow. Particle size distribution acts as a fundamental parameter in the determination of fluid flow properties in packed ore beds. In this study, we investigated the particle size distribution in dump leaching by using image analysis technique. The results showed that the particles in the dump varied from smaller than 2 cm to larger than 200 cm in diameter. P80 was calculated to be 200 cm, which was significantly higher than the historical data used by the operation. P25, P50 and P80 were found to increase non-linearly with increasing depth towards the toe of the dump, suggesting the segregation of fine and coarse particles. The image analysis results were verified by applying the rock fragmentation models. The model with the Swebrec function was found to be in better agreement with the image analysis results. Future research will investigate the effect of particle size distribution on the behaviour of fluid flow.INTRODUCTION Fluid flow plays an essential role in the extraction of valuable metals using heap/dump leaching (Amos et al., 2009). The rates of the chemical leaching reactions and microbial activities determine metal concentrations in the leachates and therefore the efficiency of the metal extraction. The reaction rates are influenced by two fundamental processes: transport phenomenon and reaction kinetics (Bouffard & Dixon, 2001). The transport phenomenon refers to the percolation of fluids through channels and pores in a packed ore bed, which carries lixiviants and reaction products to/from ore surfaces by convection and diffusion. The percolation rate of the leaching solution is determined by the hydraulic conductivity of the packed ore bed, which is a function of the permeability and the degree of saturation (Guzman et al., 2008). Permeability, an intrinsic property of a packed ore bed, is strongly influenced by the particle size distribution of the ore grains (Bouffard & Dixon, 2001). Hence, the objective of this study was to investigate the particle size distribution in dump leaching."

Jan 1, 2017

By L. Hutton, S. W. Colley

"The release of soluble salts of base metals from acid mine pits and in the waste water from metal refiners is an avoidable source local pollution and contamination. Tightening of the regulations controlling natural resource extraction and industrial wastewater discharge is mandating the removal and recovery of metals from waste streams, and the remediation of contaminated sites. There is an economic incentive in recovering the valuable copper and nickel, as the value of the recovered metal can offset remediation costs and for high flow waste streams can be a source of income. Extraction of metals from waste streams by conventional Ion Exchange and chelation resins is widely practised, but has limitations on applicability in complex and dilute feeds due to the structure and properties of polymeric resin beads. Composite Advanced Ion Exchange (AIX) materials have been developed for the recovery and purification of base metals from base metal mining and metal processing industries. A silica-composite based resin has been developed for the selective extraction of copper from high iron containing feeds. This resin can be eluted with sulfuric acid yielding a copper stream suitable for return to solvent extraction or to electrowinning. We describe the development and application of the resin and process to two acid mine drain feeds of varying copper and iron concentrations, and show that the copper concentration can be considerably upgraded even at small scale with a final metal content of >95% copper.INTRODUCTIONWaste water with high sulphate concentrations, low pH and containing complex and variable mixtures of metals is an inevitable product in the mining, extraction and metal refining industries. One problematical water source is Acid Mine Drainage (AMD) which in addition to the metals of interest also contains a wide range of contaminating elements. Purge streams from metal refining are less complex in composition but contain significant quantities of the value metals. The typical treatment of such waste streams is treatment with lime to increase the pH of the water, precipitating the dissolved metals and sulphate as a sludge of mixed metal oxides/hydroxides and sulphates. The process is effective in producing a water stream that can be safely discharged but if there are significant concentrations of value metals such as copper, nickel, zinc then there can be a considerable loss of metal value."

Jan 1, 2016

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 Tomoya Kawasaki, Tatsuya Motomura, Yutaka Yasuda

Saganoseki Smelter, one of the largest copper producers in Japan, currently operates a single flash smelting furnace to produce 450,000 tons of new copper annually. The smelter used to employ two flash furnaces, and integrated the two into one in 1996. Since then, various improvements to its facilities and technologies have been made to increase productivity. To upgrade the operation efficiency, "stability" was considered a key issue, and the measures were taken to increase the operation and facility reliability. Currently, the furnace is running at a feed rate of 215 DMT/h, while the furnace utilization has been maintained at 97%. This paper outlines recent improvements that have made to increase furnace productivity and efficiency.

Jan 1, 2014

By Claudia Gasparrini

"The ore microscope and electron microprobe, two common instruments for academic research, have not been used to full advantage in the Canadian mining industry, perhaps because they are not readily available to most mining companies.The present paper gives a description of the two instruments and of the manner in which, when used together, they contribute to the identification and description of mineralogical and metallurgical samples, and reviews the applications, to . date, in the mineral industry.The metallurgical applications can assist in determining the best separation technique for a particular metal or other economically important element, can provide explanations for poor recovery and/or liberation, can be used to determine theoptimum concentrate grade and can indicate environmental problems that may arise from the extraction process.In certain cases, the use of the two instruments may assist in the evaluation of new mineral deposits and in the determination of the origin of mineralization.IntroductionThe ore microscope and electron microprobe, two widely used instruments in universities and other research institutions, have not been exploited to their full potential by the Canadian mining industry.High-magnification, high-resolution ore microscopes, owned by most Canadian universities and government mining branches, are not widely used by mining organizations. The situation is very much the same with the microprobe. The geology departments of several major Canadian universities have easy access to this instrument. Fifteen of them, to the author's knowledge, own one and a few have already acquired or are planning on acquiring a second and later model. The mining branches of the Canadian Government have similar easy access to microprobes, as at least four of these instruments are available to them in Ottawa alone. The mining companies, on the other hand, except for the few larger ones which have their own research laboratories, have not been able to take advantage of electron microprobes in the past.This failure to exploit good ore microscopes and electron microprobes has been mainly due to a lack of expertise in the use of the two instruments for the study of metallurgical problems related to ore mineralogy. Government institutions providing research and test work to the industry are few in number, and are not always equipped with these instruments or are not geologically-oriented. Information provided on a consulting basis by universities and by government mining branches is normally limited, and frequently is not oriented to the needs of the mining company."

Jan 1, 1980

By Giles St. Pierre

"The purpose of this paper is to report in a general way on the use of the Portaspec X Ray Spectrograph.At Manitou Barvue, we are milling two types of ores, copper and zinc. The control assay practice was to take grab samples at 4 hour intervals. These samples were dried in the mill, then taken over to the Assay Office where two operators would process them. Three hours later results were available at almost the same time as the operator was ready to take his set of grabs again, leaving no time for adjustments, if any were needed.After a reduction of personnel, there were no assays available on night shift. This practice was slow and inadequate, and a new way of doing control assays was investigated.After investigation the Portaspec was found suitable for the type of operation that we had in mind. The Portaspec is a conventional dispersive type of X Ray spectrograph. The instrument consists of three parts:The Power Supply The Spectrographic Head The Digital ScalerIn our case, where dried powder samples are analyzed, the instrument was provided with a two sample holder using one for the standard and the other for the sample. The operation of the instrment does not require any degree of skill or knowledge of chemistry or spectrography.Previous to buying the instrument, six sets of six to ten samples were sent to the supplier along with the assay for each sample. These samples were Cu. HDS., Cu. Conc., Cu. tls, - Zn. HDS., Zn. Conc., Zn. tls. A definite pattern was observed. For example - six Cu. HDS. samples ranging from .40 to .90 gave 10400 counts for the lowest to 16.040 counts for the highest. The number of counts were then plotted to give percentages."

Jan 1, 1971

By K. D. Eng, W. T. Tierney

"During the past century, the development of vehicular transportation has benefitted tremendously from the performance improvement in engines in a situation where low-cost, plentiful fuel supplies were the order of the day. Engine advances were enhanced by and also dictated fuel modification to better adapt the energy source to the power plant.In discussing the several aspects of the change in approach from ""an engine and its fuel to a fuel and its engine"", the authors touch on the following areas:1. Description of an engine concept that provides the needed flexibility in fuel appetite at good efficiency to cope with future requirement s.2. The constraints placed on liquid fuel resource energy utilization efficiency by special engine-required fuel properties and the fuel efficiency of the various engine types available.3. Future vehicle engine fuel sources. This review will put into perspective the problem associated with the net energy available from future fuel sources under extensive research and development at present.4. A brief review of test data to show that fuel-tolerant and fuel-efficient engines are viable and that, in a fuel-resource-limited future, they can be a ""light at the end of the tunnel.""The Texaco Controlled Combustion System (TCCS)The TCCS is a unique means for stratified charge operation of an internal combustion engine in such a manner as to eliminate the requirement for octane or cetane number specification for the fuel. Octane rating is an empirical engine test method that evaluates a gasoline's resistance to spontaneous ignition or ""knock."" Cetane is based on a different engine test, which determines a diesel fuel's ease of spontaneous ignition . High cetane number enhances cold starting and permits high-speed diesel engine operation. As one would expect, the fuels in current use cover a band when the two values, octane and cetane, are plotted against each other."

Jan 1, 1982

By Y. Lizotte

"This paper examines the application of blasthole sloping to narrow vein mining in Canada, for ore deposits where widths are less than two metres. While the technique has now been utilized for more than ten years, it remains in the experimental stage and on-site testing is necessary for its adoption at new mining operations or in differ¬ent geological settings. It is intrinsically a safer method than other narrow vein methods in current use.The investigation describes the main operating parameters for mines recently surveyed. The criteria for method applicability are defined and the problems encountered are studied. It is concluded that blasthole sloping for narrow vein mining is a viable modern method which promises to gain popularity and that emerging fragmentation technology and blasting research can be used to further increase applicability of the stoping method."

Jan 1, 1991

By L. K. Sinclair

In situ leaching of copper has the potential to deliver low-cost recovery for soluble copper deposits of sufficient permeability. In order to provide key inputs for modeling of the in situ leaching process, bench scale test work can be used in conjunction with geochemical software to identify key leaching and precipitation reactions. A case study is presented in which a series of flow-through acid leaching tests were conducted on drill core sections from a porphyry copper deposit without crushing or grinding. Concentrations of copper and other key elements were monitored in the recirculating leach solution over several months. A geochemical model of each leaching test was prepared using Geochemist's Workbench using a combination of diffusion-controlled and reaction-controlled rate mechanisms. Key reactions included leaching of chrysocolla, iron oxides, and plagioclase. The model was able to simultaneously satisfy the evolving chemistry of the recirculating leach solution, mineralogy of the head and leach residue, measured acid consumption, and leaching rates for key minerals reported from previous laboratory studies. Opportunities and limitations for scaling up the model to simulate the commercial wellfield are discussed.

Jan 1, 2015

By George S. Martin, Michael D. Winship

"Placer Dome Inc. is the operator of the Musselwhite project located 100km north of Pickle Lake, Ontario. J.S. Redpath Limited was contracted to conduct an underground exploration program using shaft access.During the winter of1988, the shaft collar was established in 16 metres of water bearing sand and till overburden. This paper will illustrates the engineering techniques used to overcome the obstacles to installing a shaft collar in deep overburden. Specialized dewatering and piling procedures were employed.INTRODUCTIONHarold and Allan Musselwhite discovered gold in the Opapimiskan Lake area, north of Pickle Lake, in 1962. The prospectors were grubstaked by ten companies in 1973.A diamond drill program was initiated shortly thereafter.In 1983an underground ramp exploration program was carried out on the West Anticline portion of the property. The program was unsuccessful in establishing an ore reserve so surface exploration continued. In 1986the ""T"" zone was discovered. Further surface drilling was done and an over-all drill-indicated reserve of 6 million tonnes at 7 grams per tonne was outlined. The gold mineralization occurs in several vertical tabular deposits within the iron formation. In late 1987the joint venture partnership, now consisting of Placer Dome Inc., Inco Gold Co., Corona Corporation and Esso Minerals Canada, contracted J.S. Redpath Limited to conduct an underground exploration program on the ""T"" Zone.The scope of work for the project was to: 1. establish a 45 km winter road in 1988 and 1989;"

Jan 1, 1989

By E. Engelbrecht

"A pressure non-oxidative leach is employed at Anglo American Platinum Base Metal Refiners to extract nickel from a slow cooled matte. The design base requires two 80 m3 autoclaves in parallel to achieve a nickel extraction of 60% at the nameplate capacity of 32.4 ktpa nickel plated. Isothermal modelling of mineralogical and chemical concentration profiles, through a reactive mass balance, permitted rate constant parameter estimation and selection of the most probable reaction pathway. The model was validated with plant data up to a capacity of 26 ktpa Ni plated and suggested by extrapolation that nameplate capacity may be viable through one 80 m3 autoclave.INTRODUCTION Anglo American Platinum Base Metal Refiners is situated on the outskirts of Rustenburg in the North-West province of South-Africa. The refinery produces nickel cathode, copper cathode, cobalt sulphate powder, covellite rich copper pressure leach residue and bulk sodium sulphate through an integrated circuit that refines slow cooled converter matte. The converter matte is milled, non-magnetics are separated as solid nickel copper matte (NCM), and the magnetics are leached yielding a pressure vessel liquor (PVL). The remaining solid platinum group metals (PGM) concentrate after leaching is sent for downstream processing in the Precious Metals Refinery (Hofirek & Kerfoot, 1992). The work presented here is applicable to the base metals refinery which receives the two base metals feed stocks NCM and PVL. In 2009 the capacity of the refinery was upgraded from 21 ktpa nickel cathode plated to 32.4 ktpa. This paper deals with evaluating the capacity of the pressurised non-oxidative nickel leach (NOX) process which accounts for at least 28% of the nickel leached from NCM by design. The NOX design base requires two 80 m3 autoclaves divided into four compartments operated in parallel at 155°C and 600kPa(g). Elevated temperature is required to speed up the leach kinetics of particularly nickel and iron which are trapped in slow leaching mineralogical phases namely millerite and bornite, (Dinham, 2006). The stated equivalent capacity for the NOX configuration was 32.9 ktpa nickel plated at first pass nickel and iron leach efficiencies of 60% and above 80% respectively and is a key step for the selective removal of iron (Bryson, Hofirek, Collins, Stiksma, & Bereaowsky, 2008)."

Jan 1, 2017

By B. W. Clyburn

"Coals from the Corporation's Lingan and No. 26 mines are classified as high-volatile A bituminous, with a very low inherent ash and containing a/l essential properties to provide metallurgical coal, with the exception of a high sulphur content. Only through proper cleaning at low specific gravity can the pyritic sulphur fraction of the coal be liberated to an extent where final sulphur meets coking standards. This first section of the paper deals with the operation of a Dutch State Mines heavy-media cyclone circuit to achieve an actual separation in the region of 1.30 specific gravity. A discussion of the parameter of control which must be applied along with an appraisal of the results obtained is included in the paper.IntroductionVery high fluidity and unusually low ash are the outstanding characteristics of coal from Devco's mines in the Harbour seam of the Sydney coal field.However, sulphur content, mainly pyritic, ranges from 1 to 2.5070. To obtain the low and consistent sulphur level required in metallurgical coking coals, preparation at low specific gravity is required .Metallurgical coke is used as the fuel in an iron blast furnace. Its sulphur content largely determines the quantity of slag required to remove it and therefore influences furnace productivity and unit costs.Typical data on the various coal properties of importance in the production of coke are included in Table I. Necessity of Low-Gravity SeparationThe design of any coal preparation plant requires the study of washability properties of the coal to be treated to determine the quantity and quality of coal produced at a given specific gravity along with the difficulty in accomplishing that separation.Their low ash content allows the important washability aspects of Harbour seam coals to be represented by sulphur! specific gravity curves (Fig. I). This particular example indicates that a yield of 54.5% is attained, at a sulphur content of 1.20%, for a perfect separating device operating with a 1.29 S.G. cut point.Material rejected from this separation still contains usable coal, which is recovered as middlings by separating at a higher gravity."

Jan 1, 1980

By J. B. Hinzer, J. D. Harvey

"Noranda's Lyon Lake property in the Sturgeon Lake area of Northwestern Ontario was staked by Mattagami Lake Mines Limited in May 1969 to cover airborne Input anomalies. Subsequent ground geophysical and diamond drilling programs resulted in the disco very of the Boundary Extension, Lake and Creek ore zones. As of December 31, 1978, ore reserves were estimated at 3,945,000 tons assaying 6.53 per cent Zn, 1.24 per cent Cu, 0.63 per cent Pb, 3.42 oz/ton Ag and 0.010 oz/ton Au.These deposits are hosted within the South Sturgeon Lake volcanic pile of Archean age, which consists of several cycles of basic intermediate and felsic volcanic materials overlain by a sedimentary iron formation and built upon a plutonic base (Franklin , ' 1975). The top 50 m of the second felsic cycle, according to mine terminolo gy, contains the mineralization within Quartzphenocryst- bearing felsic lapilli tuff and underlying thin discontinuous graphitic sediments and altered coarse pyroclastics. The basal andesitic member of the overlying cycle forms the hanging wall to the ore deposits.Although there is no alteration pipe below the deposits, the coarse footwall rocks are permeated by chlorite, garnet, carbonate, iron sulphide and magnetitie-bearing veins intensifying from west to east.Immediate host rocks are alkali depleted and MnO, FeO, Zn and Cu enriched compared to Goodwin's (1972) average Archean rhyolites. Bedded pyrite-pyrrhotite-chalcopyrite lenses with sphalerite-rich tops are underlain by weakly developed stringer mineralization.Traversing eastward from the Lake Zone to the Creek Zone and toward the Sturgeon Lake Mine deposit, more rapid facies changes, more pronounced chloritic and carbonate alteration, the presence ofgarnets, greater MnO, FeO, CaO and Ag abundances, and increasing Zn/Cu and MnO/FeO ratios are apparent."

Jan 1, 1981

By Derrick Hunter, Pat Feighan, Keith Chrystall, David Wells

"Equipment which may be remotely operated, has some degree of on-board intelligence, and which for periods of time may operate autonomously, is referred to as telerobotic. Recent advances in electronics, computers and hydraulic equipment have dramatically reduced the cost and simplified the process of converting standard industrial equipment to telerobotic control. The benefits of telerobotic equipment include improved safety by removing the operator from dangerous situations, reduced maintenance costs and increased productivity. This technology has been proven in various military, nuclear, and police applications.The surface mining industry has expressed an interest in automation and is characterized by a willingness to use remotely operated equipment, however, the majority of telerobotic equipment currently in use is experimental or prototypical. Potential applications of telerobotic equipment for surface mining include remote operation of equipment near dangerous high walls and other unsafe areas, utilization of robotic trucks for routine hauling operations, and control of jointed equipment. In addition, component technologies of telerobotic systems are relevant to various forms of condition monitoring, operator feedback systems, and vehicle positioning.Attention must now be directed toward resolving more complex problems associated with enhancing feedback to the operator, improving the man/machine interface, and ultimately, improving efficiency. Removal of the human operator from the work site introduces significant complications in replacing the sensory inputs that an operator normally uses to efficiently run his machinery. These can be difficult to define and even more difficult to replicate remotely and may include restrictions pertaining to vision, hearing, and touch.In cooperation with Defence Research Establishment Suffield and the Alberta Research Council, Robotech Industries Ltd. is pursuing the development of additional technologies to further enhance an operator’s ability to control remote telerobotic equipment. These developments include a head-mounted display, additional control station displays and improvements to coordinated motion control software. Prototypes of these developments are expected to be completed and tested by the fourth quarter of 1997."

Jan 1, 1996

By P. Hanniala, S. Harkki, B. Andersson

"The Outokumpu Flash Smelting Process was put into commercial operation in 1949. The original process was based on the use of preheated air. The adoption of oxygen enrichment of the flash smelting process air in 1971 was a crucial improvement, especially for smelter capacity. Oxygen use according to the Outokumpu method means selection of the most suitable oxygen content for the process air on the basis of the concentrate composition, capacity and matte grade. The furnace is not bound to only one fixed degree of process air oxygen enrichment; the oxygen content may vary from 21% to 100%.The degree of oxygen enrichment and the matte grade are the most important process parameters in reducing the operating costs of the whole system, including smelting, converting and acid production. Raising the matte grade allows more efficient use of the reaction heat in the smelting stage. Sulphur is recovered in a high-strength, constant-flow gas stream. The blowing time in the converters is reduced considerably.Oxygen enrichment and high matte grade improve the energy efficiency of the plant complex as long as the surplus heat from the system is not wasted. When the operating costs and investment expenditure of the total plant complex are taken into account, a reasonably high degree of oxygen enrichment (35-80°/0) is the best alternative in practice. Existing operating smelters have achieved single-stream thoughputs of over one million t/yr of concentrates.HistoryLocal capital and operating costs as well as lower energy consumption per unit of metal produced are now the crucial factors in determining the choice of process. In the late I940s, the same reasons prompted Outokumpu to develop the original flash smelting process in Finland. Between 1900 and 1940, very few technical changes in pyrometallurgical copper production took place. However, the commercial use of the flash smelting technique began a new era in metal extraction from sulphide concentrates. The characteristic feature of the method is that the concentrate is smelted in suspension: this offers the most favourable conditions for heat and mass transfer, and thus high reaction velocities. Outokumpu was the first to exploit the known advantages of flash smelting in a commercial installation at Harjavalta in 1949."

Jan 1, 1982

By T. C. Holmes

Introduction The Dome mine, in the Porcupine mining camp of northern Ontario, is one of the important gold mines of the country, having produced over 139 million dollars worth of gold from the commencement of production in '1910 to the end of 1944. The geology of the mine is complex and a number of types of ore are known, each occurring under particular conditions. The mine workings are very extensive and by far the greater part of them have been geologically mapped only in reconnaissance fashion. By 1940, when the writer joined the mine staff, the orebodies in the sedimentary trough and the 'nose' orebodies, the first types to be developed, were almost worked out and many workings were inaccessible, so the descriptions of these types are based largely on study of the plans and records. The same applies to a lesser extent to some other types. At various places in this paper, statements are made as to the mineralogical or chemical composition of the rocks. Most of these determinations are based on examinations made with a hand lens and cannot, therefore, be regarded as very reliable. General Geology As there are several types of ore in the mine, occurring under quite diverse conditions, a brief outline of the geology is given here, sufficient to provide a general picture into which the fuller descriptions given with each type of ore can be fitted.

Jan 1, 1947

Proper water and thermal management is essential for obtaining high performance of Proton Exchange Membrane Fuel Cells (PEMFCs). A steady, two-dimensional water and thermal management model was developed, aiming at considering pressure drop, open circuit voltage variation with stack temperature, water vapor effects on membrane conductivity, which made the model physically more reasonable and more suitable for various operating conditions. The model could predict the distributions of a series of important parameters along the flow channel, and thus the effects of various operating and design parameters on the fuel cell performance could be investigated easily by numerical trial-and-error method. The modeling results compared well with the available experimental results from the literatures. The results also showed that the humidification is crucial for the performance of PEMFCs. The model could be a very useful engineering tool for the optimization of PEMFCs.

Jan 1, 2005