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By C. Samson, R. S. Smith, S. W. Hefford

"Abstract - Time-domain electromagnetic systems are most sensitive to highly conductive targets during the transmitter on-time. Data collected during the on-time is highly influenced by the geometric relationship between the transmitter and the receiver. Unless corrections can be applied for these geometric variations, the ability to correctly detect and identify highly conductive targets can not be fully realized. Variables affecting the relative position between the transmitter and receiver include changes in the position of the receiver with respect to the transmitter, variations in transmitter attitude, and transmitter loop deformation. The level of accuracy in the determination of the relative geometry required to permit complete removal of the effects due to geometric variations is different for each of the variables and is dependent on the depth of the target. The most influential geometric variation involves changes in the relative position of the receiver with respect to the transmitter along the direction of flight; this variable, therefore, requires the highest degree of accuracy. The accuracy required for receiver motions along the vertical direction is roughly one order of magnitude less, and in the lateral direction, several orders of magnitude less. The objective of this paper is to relate the sensitivity of the response to transmitter-receiver geometry to the ability of an airborne, time-domain electromagnetic system to resolve a highly conductive vertical target. This is achieved by a detailed analysis of the effect of the individual x, y, and z distances between the transmitter and the receiver, the transmitter attitude (roll, pitch, and yaw), and transmitter deformation.Sommaire - Les systèmes électromagnétiques en domaine temporel sont particulièrement sensibles aux cibles à forte conductivité durant le temps d’excitation. Les données collectées durant l’émission du transmetteur sont fortement affectées par les relations géométriques entre le transmetteur et le récepteur. Si un facteur de correction n’est pas introduit pour tenir compte de ces variations géométriques, la capacité de ces systèmes à détecter et identifier correctement les cibles fortement conductrices ne peut pas être pleinement réalisée. Les facteurs affectant les positions relatives du transmetteur et du récepteur comprennent les changements de position du récepteur relativement au transmetteur, les changements d’altitude du transmetteur et la déformation de la boucle du transmetteur. Le degré de précision requis pour déterminer la configuration nécesaire pour compenser complètement l‘effet des changements géométriques est différent pour chacune des variables et dépend de la profondeur de la cible. Les changements géométriques qui ont le plus d’influence sont ceux qui font varier la position du récepteur relativement au transmetteur dans l’axe de la ligne de vol; c’est donc cette variable qu’il faut contrôler avec le plus de précision. La précision requise pour le suivi des mouvements du récepteur le long de l’axe vertical est moindre d’environ un ordre de grandeur, tandis que selon l’axe latéral elle est diminuée de plusieurs ordres de grandeur. Le but du présent article est d’établir comment la susceptibilité de la réponse à la géométrie transmetteur-récepteur affecte la capacité d’un système électromagnétique en domaine temporel aéroporté à reconnaître une cible verticale fortement conductrice. Cet objectif est atteint par l’analyse détaillée de l’effet individuel des distances x, y, et z entre le transmetteur et le récepteur, l’attitude du transmetteur (lacet, roulis, tangage) et la déformation du transmetteur."

Jan 1, 2006

By M. A. Power

The diamondiferous Drybones Bay kimberlite pipe is the largest pipe (900 m by 400 m) discovered to date in the Northwest Territories. The pipe intrudes granodiorite of the Archean age Defeat Pluton and contains crater, reworked crater (epiclastic) and diatreme facies kimberlite. In-situ measurements of seismic p-wave velocity were recorded with in-line refraction arrays over representative areas. Refractions from fresh kimberlite were recorded over epiclastic facies kimberlite in the eastern portion of the pipe and returned an average velocity of 4300 m/s. Refractions from weathered kimberlite were recorded on all lines and returned velocities ranging from 1900 m/s to 2200 m/s. Granite surrounding the pipe returned an average velocity of 5400 m/s. The results indicate that there is a definite contrast in seismic velocities between kimberlite and country rocks at Drybones Bay and suggest that seismic refraction surveys may be an effective means of screening kimberlite targets in glaciated areas underlain by igneous or metamorphic rocks.

Jan 1, 1998

By Norman A. Jull

"IntroductionThe scope of this paper is intended to deal mainly with cyclones in grinding circuits. However, the section on Cyclone Equipment, contains more general descriptions, to cover most of the cyclones used in mineral separation plants.Cyclones as heavy media separation vessels are discussed by Mark Freberg (this volume). Their use in tailings deslirning is discussed by P.C. Lighthall, eta/. (this volume).Cyclone EquipmentCyclone TerminologyApexObviously, the apex of a cone is the smallest end. However, with cyclones the term is usually used for the fitting which is attached there to control discharge of the underflow stream.Note that the cyclone need not be so mounted that the apex is the lowest point, although that is the most common method. Keeping the apex below the rest of the cyclone helps avoid plugging when the underflow contains very large particles and the tonnage of underflow solids can fluctuate.Various devices for adjusting apex diameter or otherwise controlling the underflow are discussed later under ""Cyclone Construction"".BypassingThe transport of a portion of feed slurry directly to underflow so that classification is bypassed by that portion of feed.This action is fundamental in any hydraulic classification, whether gravity or centrifugal, because the large particles going to underflow have some void volume between them, which remains filled with feed slurry.D50By definition, D50 is that particle size which has an equal probability of going to overflow or to underflow.It is calculated by drawing a curve of recovery vs particle size and noting the size at which 500Jo recovery occurs.This may be done equally with corrected or with gross recovery (see below) and the resulting value should therefore be identified as d50c (corrected d50) or as d500 (gross d50).Note also that it is common in industry practice to plot size analysis data on the retained size rather than on the average of passing and retained (the middle of the size band). To portray sizing alone it makes no difference, but to read a D50 value off a curve of corrected or gross recoveries, it is essential to plot those values on the average size of each band."

Jan 1, 1989

By J. W. Meier

Introduction The great importance of air warfare during World War II and the introduction of large-scale air transportation and airborne operations created an immediate demand for large quantities of high quality light alloy products. Before this war, the use of magnesium, the lightest structural metal, was barely in the development stage, and considerable research work was needed to overcome difficulties in improving its properties and to attain uniform quality in mass production of magnesium alloy products. The Canadian Bureau of Mines was frequently called upon, by various agencies of the Armed Forces and of the newly established war industries, to examine magnesium alloys that had failed in fabrication or in actual service, and to advise on proper alloys and fabrication methods to be used. Failures in magnesium alloy castings were connected mainly with lack of knowledge of proper founding and surface-protecting techniques. Most of the defects were due to microporosity and faulty heat treatment. To aid the foundry industry, small-scale investigations were started on the effect of various factors in the casting technique in order to improve the quality of the products. These investigations were made in co-operation with representatives of the Armed Forces and the Canadian magnesium industry. This work was later co-ordinated into a broad research programme on magnesium alloys, comprising problems on melting, refining, various casting methods, heat treatment, and testing of properties of standard and special alloys. This research programme? is still in force, and the present paper contains some results of the first series of investigations on magnesium casting alloys carried out at the Experimental Foundry of the Bureau of Mines.

Jan 1, 1948

By J. C. Gathje

Newmont acquired the Phoenix Project through the acquisition of Battle Mountain Gold in 2000. Shortly after the acquisition, Newmont Metallurgical Services (NMS) and Nevada Operations began development work on a process to Pressure Oxidize (PDX) precious metal rich copper concentrates from Phoenix using the Lone Tree PDX facilities at Valmy, Nevada. The high precious metals content of the Phoenix concentrate - Au up to -300 g/t and especially Ag, up to -1700 g/t - led Newmont to the development of a High Temperature PDX process that achieves high cyanide leach recovery of Au and Ag, from the PDX solids, without the requirement for a messy and expensive "lime boil" or sulphate destruction process. Base metals content in Phoenix concentrates range from: 15-25 % for Cu, 1-10 % for Zn and 0-2 % for Pb. Excellent solution extraction of Cu and Zn is achieved while Pb is precipitated in the PDX residue. In addition to achieving high Au and Ag recovery this process produces very clean PDX discharge liquors that require minimum effort to remove contaminant metals and PDX solids that have superior settling and filtration characteristics. All of these factors contribute to lower capital and operating costs for the overall process. This paper describes the laboratory and PDX pilot plant developments for this process.

Jan 1, 2004

By G. Ellie, D. F. Coates

"The mining of coal in thick and inclined seams is difficult, and there are only a few countries in the world that are really interested in the problems associated with their exploitation. In France a considerable amount of investment has been made in the mechanization of systems appropriate for such conditions.For seams inclined up to 50 degrees, of normal thickness, a new system was introduced in 1967. It consists of a longwall advancing to the rise with walking props, a shearer and hydraulic backfill. During the first two years the panel productivity was an average of 25 TN/MS, and they foresee the possibility of reaching an average of 30 TN/MS.A system for thick beds, both horizontal and inclined, is in p•rocess of being mechanized. In 1969 they started with a method consisting of a longwall in a footwall slice, or sub-level drifts with walking props, and caving and drawing up to a height of 20 m of coal. Recent experiments with a shearer have produced panel productivities between 9 and 11 TN /MS, and there is hope that with experience an average of 16 TN/MS will be obtained.In 1964 a method was initiated for beds inclined from 60 to 90 degrees, based on a mechanical cutter designed by the collieries in Lorraine. An overhand slice of 4.2 m in height is taken with a drum cutter mounted on the end of a boom. Hydraulic fill is placed at the completion of a slice. The face productivity, which has been from 13-20 TN /MS, can be perhaps increased to an average of 22 TN/MS. For those companies with important reserves in inclined and thick seams, these French systems may be worth the trouble of examining in some detail."

Jan 1, 1972

By T. Loos

The Norddeutsche Affinerie operates an Outokumpu-Flash-Furnace as a smelting unit. The pyrometallurgical slag cleaning process is based on the slag reduction and settling in the electric furnace. Since 1972 when the slag cleaning furnace was built the throughput could be increased fourfold. However, an extensive optimisation effort is required in order to keep the copper loss low. A parameter study with a neuronal network model based on real process data was conducted to identify parameters impacting on the copper loss in the slag. It could be demonstrated that the main parameters responsible for copper loss in the final slag are fixed parameters of the flash furnace. For a better understanding of the copper loss in the electric furnace microscopic analyses of the slag structure and viscosity measurements were performed. Based on these results the reduction and settling of the copper containing droplets could be increased in both pilot plant studies and industrial scale. 4

Jan 1, 2007

By Christina Graf

A synthesis of colloidal gold shell particles with a silica core is described. Small gold nanoclusters were attached to the functionalized surface of colloidal silica particles. Reductive growth and coalescence of these clusters lead to the formation of a closed gold layer. By variation of the thickness of this gold layer and the radius of the shell it is possible to adjust the plasmon resonance of the gold shell particles over the whole visible and infrared region of the spectrum. The optical properties of the particles made are in good agreement with theoretical calculations for coreshell particles. Due to their low polydispersity these gold shell particles form in solution large crystals with submicron lattice constants. It is also possible to produce hollow gold shells by dissolution of the silica core. A new method to coat the silica core gold shell particles with an additional outer silica shell is also presented. This allows due to a reduction in the Van-der-Waals forces to make more permanent dried crystals and facilitates functionalization of the particles for use in various photonic applications.

Oct 1, 2003

By Raymond B. Hryciuk

Environmental auditing has evolved rapidly over the last decade — first in North America, then Europe, and most recently in Asia — into a widely practiced discipline designed to provide senior management with assurance that operations are being managed in compliance with established governmental standards, internal company policies, and good industry practices. This paper first examines the evolution of environmental auditing, focusing in particular on three interlocking driving forces: company initiatives, collaborative industry initiatives, and government initiatives. Characteristics of effective audit programs, those that have emerged among the leaders, are discussed, including: objectives, scope, coverage, approach, staffing, and organizational considerations. The author then addresses important future trends and developments for environmental audit program design, content, and coverage.

Jan 1, 1996

By H. J. Conolly

The area around Osisko lake, the Horne mine, and the town of Rouyn, in northwestern Quebec, presents a most interesting structural problem. The present discussion is confined to an area around Osisko lake, about six miles long and three miles wide, shown in Figure 1. The writers are particularly indebted to Mr. Thayer Lindsley, of Ventures Limited, who sponsored the investigation and gave permission to publish this paper. Mr. H. L. Roscoe and Mr. Oliver Hall, of Noranda Mines, Limited, gave every possible assistance; and the Noranda geologists, Mr. H. M. Butterfield, Dr. Peter Priee, and Dr. G. G. Suffel, contributed many data and ideas. It is a pleasure to acknowledge also the fuidance of Dr. W. F. James and Dr. B. S. Buffam and the full use made o their maps and criticism. Dr. M. E. Wilson and Dr. A. Lang, of the Geological Survey of Canada, kindly furnished data on the geology in neighbouring fields. Mr. E. Bailey assisted ably in the field, and Mr. H. F. King kindly reviewed the text. Memoir 166 of the Geological Survey of Canada, The Geology and Ore Deposits of the Roztyn-Harricanaw Region, Quebec, by Cooke, James, and Mawdsley, proved an invaluable source of information. STRATIGRAPHY The following stratigraphie sequence is based in part upon the interpretation of the structure as outlined in this paper:

Jan 1, 1936

By C. E. Rodgers

WHEN I was asked to prepare, for presentation at the 1938 Annual Meeting of the Institute, some data concerning low-discharge grinding at the Sylvanite mill, it seemed entirely reasonable to expect to have at my disposal the results of at least four full months' operation after the last unit, as then proposed, was installed. Delays in delivery of equipment, nevertheless, shortened the interval, as will be shown herein. In submitting the data contained in this discussion, I wish distinctly to state that the intention is not to claim that final conclusions can be reached at this time concerning our operation. Test periods, in certain instances at least, have been too short for this purpose, although some, where so stated, have been extended through March and April. It is hoped, however, that an advantageous trend in practice can be shown and that the experience related may be of interest to others who are now operating, or who are considering the operation of, low-discharge grinding mills. In the plant under review, four mills are in use: one primary and three secondary. Present mill capacity (grinding, as shown by screen test, about 99 per cent through-200-mesh and approximately 88 to 89 per cent minus-325-mesh with infrasizer giving about 90 per cent of the latter) averages about 525 tons per day. A brief description of each unit will be given and comments will also be made relating to operation. This will be followed by certain test data from which, in conclusion, operating results are summarized.

Jan 1, 1938

By K. S. Fraser, H. J. H. Pieterse

"A pressure oxidation plant to pretreat refractory sulphide ore at the Goldstrike plant in Nevada, was commissioned in early February 1990. The plant, with a nominal capacity of 1363 t/d, was commissioned over a one-week period and achieved design capacity and availability within ten weeks an unusually short period for a plant of this complexity.The pressure oxidation process is conducted under elevated temperature and pressure conditions, and in a corrosive environment. These conditions demand that the process and engineering design of the plant be carried out in a much more sophisticated and detailed manner than is normally required in a conventional gold plant.This paper provides an account of the process and engineering design of the Goldstrike pressure oxidation plant with special emphasis on the design of the vessels, slurry pumps, piping, valves, and control systems.BackgroundLocationThe Goldstrike property is located in Eureka County in northcentral Nevada on the Carlin geological trend. The mine is approximately 40 km northwest of the town of Carlin which is situated on Interstate Highway 80. The minesite is located 1700 m above sea level in the Tuscarora Mountains.Initial Goldstrike OperationsShallow, low-grade mineralization was discovered by diamond drilling in the Goldstrike area in the 1960s. A heap leach operation was established in the mid-I970s by the previous owners. The Post deposit was discovered in 1982. Gold production by mining and heap leaching reached I t/a (40 000 oz/a). American Barrick purchased the property in 1987 and started an aggressive program of deep drilling. This led to the discovery of the Betze and Deep Post deposits and established sufficient reserves to justify an initial 4100 t/d mill and a 5 500 000 t/a heap leach operation"

Jan 1, 1992

By J. W. Merkley, K. B. Hustwick

"The authors describe the use of a computer system for the control oj warehouse inventory at Cominco's Canadian operations. The challenge presented by the company's diverse products and various locations necessitated a practical approach to operational and manpower requirements. The utilization of modern forecasting techniques, manual intervention and exception reporting provides system flexibility. The system also provides both operational and management control to set required service goals at the lowest inventory levels for inventory management.IntroductionCominco Ltd. is a Canadian company, with international operations, the principal business of which is zinc, lead and chemical fertilizer s. Its involvement is fully integrated and range s from mineral exploration through mining, smelting, refining and by-product production to international marketing. It also embraces related services, including trade, wharfarge and power. With head office in Vancouver, it is involved, directly or through subsidiary or associated companies, in Canada and in the United States, Greenland, Europe, Australia, India and Japan.Cominco has over 12,000 employees and 26,000 shareholders, with 91% of all shares held in Canada.Cominco's Inventory Control System is one of the most extensively used computer systems employed by the company. Also, inventory control is regarded as one of the most economically successful computer applications to be undertaken by the Data Processing Services (D.P.S) Group that was responsible for the development of the Inventory Control System.The main use of automatic inventory control has been at operating plants in Western Canada and the Northwest Territories, which are separated by large distances. Each location has equipment-intensive mining and processing operations and it is essential to maintain control of parts and supplies inventories. Some of these locations are remote from urban and industrial centres and it is important to avoid the adverse effects of high personnel costs and re-training due to turnover."

Jan 1, 1982

By Dawei Yu, Kinnor Chattopadhyay

In the nickel industry, molten slags produced from a Pierce-Smith converter contain significant amounts of valuable metals in the forms of oxides and physically entrained matte droplets. A slag cleaning step, which takes places in an electrical slag-cleaning furnace, is therefore required to recover the valuable metals as a common practice. Utilization of a waste material from aluminum industry (i.e. spent potlining) as a flux to improve the slag cleaning in terms of both the metal recovery and the operation efficiency was studied by simulation with FactSage program. Results show that the addition of SPL could substantially reduce the slag viscosity due to its fluoride values, thus accelerating the settling of matte droplets. The carbon value in the SPL could also help increase the metal recovery by reducing the valuable metal oxides followed by settling.

Jan 1, 2015

By C. Doucet

Since 2001, CANMET Mining and Mineral Sciences Laboratories (MMSL) have worked with Falconbridge Ltd. (now Xstrata Nickel) to evaluate trends in the strength development and water retention properties of a novel backfill material for underground mining, called gelfill. Between 2004 and 2006, extensive laboratory tests were undertaken under the leadership of the Deep Mining Research Consortium (DMRC). This paper compares results obtained from samples circulated through a mini-flow loop and a simple mixer. Although many parameters were studied over the last five (5) years, this paper focuses on the investigation of the effect of the mixing method, sequence and time, and the curing environment on strength development and water retention of gelfill. It was found that binder should be added as a powder to the mix in the mini-flow loop, and that mixing slurry in the mini-flow loop as opposed to the mixer generally yielded higher strengths. The practical implications of these observations are the subject of an on-going underground trial that will compare laboratory and in situ properties of regular slurry fill with gelfill.

May 1, 2007

By Leon J. Perrier

The paper describes the equipment in use, haulage grades, road conditions, tire sizes, tire performance and related problems. Various types of failures and causes, corrective action taken, tire records and reporting for control are also discussed.

Jan 1, 1977

By E. Gaucher, D. C. Gagnon

"The paper refers to methods and concepts used in the computer treatment of banks of geophysical, geochemical and geological data, relating to the exploration of massive sulphides. In particular, a data bank of 400 drill holes on independent conductors can be used to calculate probability levels of intersecting a certain quantity of sulphides according to the characteristics of the conductor. Inversely one can, using the data bank and some cost assumptions, simulate and optimize the cost of intersecting a certain quantity of sulphides by selecting drill targets among conductors according to conductivity, magnetism or gravity. Problems of noise, inherent in any simulation, are illustrated in this paper by the results of a study of the nomenclature of volcanic rocks of 27 drill holes by forty geologists. Compilations of data banks are long and timeconsuming, and it would help to standardize to allow exchange of data. We believe that such efforts may result in the discovery of more mineral deposits and at a lower cost. The present study is supported jointly by SOQUEM The New Jersey Zinc Co. and Cominco Ltd."

Jan 1, 1973

By J. Lammers, D. Adams

Most pressure oxidation operations introduce oxygen through a large multi-use nozzle in the vapour space of the autoclave. Sparge pipes extend inside the vessel to the point of discharge below the compartment agitator. However, two zinc pressure leach operations have successfully used a bottom entry oxygen sparge system for a number of years. Recently, the concept has been used in a whole ore gold pressure oxidation operation as well as a copper pressure leach plant. Both of the latter operations also introduce cooling water for temperature control through the same sparge pipe. This paper addresses the benefits of the bottom entry system with regards to autoclave performance and the positive effects on agitator performance.

Jan 1, 2004

By D. Campbell Mackenzie

THIS paper is submitted primarily to put on record the results of a number of experiments carried out at the Wingdam mine of Consolidated Gold Alluvials of B.C., Ltd., with the object of establishing a reliable method of concentration of 'wash' and a maximum recovery of gold from the concentrate. It will be generally admitted that, during the last two decades, a tremendous amount of research work has been carried out, both by private companies and Government departments, with a view to improving the technique of the recovery of gold .from quartz veins or lodes. So thorough have been these investigations that milling practice at a modern quartz gold mine is almost an exact science, carried out with meticulous accuracy. In placer mining, on the other hand, very little departure from old traditional methods can be noted, with the exception perhaps of the more modern gold dredges. This may be due to the fact that the concentration of placer gravels, up to a certain point, is comparatively easy. Only a simple equipment of sluice box and riffies seems necessary where the gold is coarse and the gravel free from clay. In the early days of placer mining, when claims were rich and fairly 5hallow, nobody worried very much about fine gold; and, if clay was present, an enlarged dump box was constructed in which the gravel was subjected to a rather desultory puddling. That large quantities of gold are lost in normal placer practice is generally admitted. Some 26 years ago, I had inspectorial charge of many bucket dredges on the Ovens river, in Australia. Occasionally it was necessary for a dredge to work through its own tailing to reach a new section, and almost without exception enough gold was recovered from these tailings to defray the total cost of moving the dredge. Since those days, the technique of gold recovery in dredging has been considerably improved and it is still receiving close attention. Outside of dredge mining, most placer operations, deep or otherwise, are as they were-notorious gold losers, paying little attention to the recovery of fine gold and taking an absurd amount of time over each clean-up. In the Cariboo district of British Columbia, the alluvial gold is usual y associated with varying quantities of black sand (magnetic) and grey sand (non-magnetic); and it can be taken as axiomatic that, if you save all the black sand and grey sand, you save practically all the gold. It is on this hypothesis that we have carried out our research work and brought our recovery system up to its present highly satisfactory standard.

Jan 1, 1937

By W. H. White, A. J. Sinclair

"Unaltered biotites from three samples of monzonite and gabbro from the Copper Mountain stock and a single sample from a pegmatic biotite-chalcopyrite vein cutting the Triassic Wolf Creek formation have a mean K-A age of 193±7 m.y. These data support a suggestion based on geological evidence that Copper Mountain ore deposits are related genetically to the Copper Mountain stock.A cogenetic mineral pair (biotite and clinopyroxene) from a sample of sericitized and chloritized monzonite of the Copper Mountain stock have identical K-A ages of 150 m.y., which probably represents a time of wide-spread, post-ore, hydrothermal alteration. This alteration is believed to be related genetically to a group of post-ore intrusions known as the ""mine dykes,"" suggesting that they also have an age of 150 m.y."

Jan 1, 1968