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By D. P. Ziegler

Formulas relating economic optimum busbar cross sectional areas to busbar cost, electric price and financial parameters are reviewed and revised. Application of the formulas is illustrated with discussion of the appropriate choice of parameter values and the sensitivity of the optimum to the parameters. The extension of the single busbar concept to optimization of more complicated arrangements of bus for smelting pots is complicated by the constraint of obtaining a specified current distribution. An example problem illustrates the optimization of a section of a bus network containing a fork, with the imposed limitation of achieving a specified uniformity in the current. In cases where the current in the individual conductors may vary, Kelvin's law does not apply. Further extension of the technique to a full pot set of conductors poses additional problems which are discussed, but whose solution has not yet been accomplished. Aluminium 2006 45th Annual Conference of Metallurgists ofCIM Montreal, Quebec, Canada Edited by

Jan 1, 2006

By Hans Lundberg

Introduction Today, geophysical exploration is recognized as a special science wedged between geology and mining. Universities and technical institutes have special professors teaching geophysics applied to oil and ore prospecting. The list of literature on geophysical exploration has grown from practically nothing at all some twenty-five years ago to ~ several thousands of books, some of them very imposing volumes. Most of the methods now used have been developed since the first World War, and very large systematic exploration campaigns have been carried out in many places, in many countries. It has been rather difficult to obtain enough information as to what is going on in Canada. However, since the Associate Committee on Geodesy and Geophysics of the National Research Council became more actively engaged in promoting geophysical research, it may be easier to obtain information and, in the future, the quarterly issued Canadian Geophysical Bulletin may throw considerable light on the current geophysical activities in Canada. Some twenty crews have been engaged the last few years in geophysical prospecting for ore. In the United States, between 500 and 600 crews are employed exclusively in geophysical prospecting. Most of these, however, are engaged in oil exploration. During the winter 1942-1943, the German Government employed some fifty crews on geophysical exploration, and some ten crews were working for private enterprises.

Jan 1, 1948

By D. B. Dreisinger, M. Mokmeli, B. Wassink

Dissemination of selenium and tellurium in sulphide minerals results in the contamination of pregnant leach solutions and electrolytes in the hydrometallurgical treatment of sulphide ores and residues. The selenium and tellurium content of the copper sulphate-sulfuric acid solution may be reduced into insoluble precipitates of copper selenides and tellurides using cuprous ion. This study presents the use of the thermodynamics and kinetics for the removal process of selenium and tellurium in real life application. Dominant species of selenium and tellurium in acidic copper sulfate solutions were identified and the reduction rates of species were compared. The findings were applied to industrial conditions by modeling the Vale’s CRED (Sudbury, Canada) plant’s selenium and tellurium purification circuit. Rate reducing factors on selenium and tellurium removal were identified and discussed.

Jan 1, 2014

By M. A. Kessick

Current treatment and disposal procedures are compared for clay slimes resulting from the extraction of Alberta oil sands, the extraction of Florida phosphate matrix, the recovery of diamonds from kimberlite deposits in South Africa, the recovery of kaolin from clay deposits in southwest England and the upgrading of bauxite ore. Published research in the area is reviewed, and common trends which are emerging in the disposal of clay slimes are discussed.

Jan 1, 1978

By Douglas A. Sloan

AN INCENTIVE or bonus system of payment is commonly used for mine labour. The incentive rates are usually based on the variable units of production, such as dollars per foot of drift advance or cents per ton of ore broken. Portions of the work that must be done to achieve the units of ?production are independent of the production unit and tend to be fixed work for the shift or for the job, irrespective of the production achieved. This fixed work has considerable influence on the equity of incentive rates. The effect of fixed work is to accelerate the loosening or tightening of rates if the production task is over-achieved or under-achieved, and of increasing the loosening of rates loosely set and the tightening of rates tightly set. This gearing of mine contract rates is the reason why changes in conditions, materials, equipment, or methods will change the incentive earnings to a greater degree than would normally be expected. Obviously, therefore, care should be taken in the setting of the task for incentive rates as the gearing makes an inequitable rate even more inequitable.

Jan 1, 1958

By Güney

"An investigation carried out to determine the tendency of coals to heat spontaneously in terms of time-temperature curves coupled with the resulting oxidation products in an adiabatically controlled laboratory setup is described. Tests were made at differing moisture conditions, including oxidation and also oxidation with either adsorption or desorption of water vapour on coal.From the experimental evidence, there is reason to believe that the oxidation of coal, although an important factor, is not the predominant one in the development of spontaneous heating. In addition to the temperature increase in coal and the gaseous products evolved due to auto-oxidation, the process is accelerated by adsorption and retarded by desorption of water vapour on coal."

Jan 1, 1971

By S. Devereaux, P. Gover, S. Everett

Having real-time data of blast furnace burden profile with respect to burden height and temperature is critical to making informed decisions on blast furnace operation. Given the high temperature and gaseous environment within the blast furnace shaft, traditional instrumentation has been limited at providing the level of real-time feedback information needed to optimize blast furnace operations. Infrared thermal imagery technology provides non-contact temperature measurement across the entire burden profile, allowing for better understanding of the dynamic movement of the burden within the blast furnace shaft. This technology increases blast furnace performance by improving the decision-making process for hour by hour operations. This paper will discuss the development of incorporating infrared thermal imagery technology into the operating strategy of a lead blast furnace.

Jan 1, 2015

By Ralph L. Rutherford

Geologists or mining engineers familiar with geology are frequently requested by mine operators to give correlation in-formation regarding some mining property with respect to an adjacent area on one at some greater distance. It is the object of this article to mention a few of the difficulties involved in securing this information and to point out some of the salient factors upon which correlation is dependent. In view of the nature of the following discussion, a brief statement of the general character of coal formations .. seems appropriate. Coal formations, by reason of their environment of deposition which is in fresh or brackish water, exhibit the features common to continental deposits, in contrast to those of marine deposits. Such deposits are characterized by rapid variation in thickness and in lithological character both later-ally and vertically. (Plate 1 A). They consist essentially of sandstones and clay shales with all gradations between them, and also a few beds of coal and frequently some conglomerates.

Jan 1, 1924

By J. Scrimgeour

"The word ""instrumentation"" has expanded from its original meaning, which in engineering perhaps referred to measuring apparatus alone. In its broadest form, it now includes sensors, display instrumentation, standard pack-aged controllers and, most recently, the use of stored program computers for on-line process control. The paper traces the evolution, in tutorial form, of the successive application of mechanization, measurement instrumentation, automatic control, central operating systems, programmed control, process computer control, direct digital control and, finally, hierarchies of computers used for process control and corporate management as a fully integrated business system. In the field of industrial minerals, the cement industry has seen the most widespread acceptance of these techniques. Computer control has been accepted as the way of life for the blending of chemical materials and for on-line control of the cement kiln. Accordingly, the cement application is selected for further presentation in the paper. This illustrates the trend progressing from control of single loops on process variables toward the objective of total control of the product quality. The economic justification for instrumentation, centralized control, automatic control and computer control is .discussed with reference to savings in fuel, maintenance, operating labour, depreciation, power and product quality improvements."

Jan 1, 1967

By T. Patching

"A GLANCE BACK AT what has happened in the past is often a useful guide to the future, although it should be used mainly to provide a sense of direction rather than a map that must be followed. As a preamble to discussing some of the questions posed by the organizing committee it may be appropriate to briefly review the distribution and careers of the graduates of our Department since the first degree in mining engineering was awarded in 1916. An attempt has been made to keep a record of the locations and careers of the Department's 540 graduates in mining and metallurgical engineering. Almost all of those who graduated before 1930 have now retired, but a very large proportion held positions as senior executives prior to retirement. A major proportion of those who graduated before 1950 are now in what might be considered senior management positions. Those who have 10 to 20 years of experience are generally in work of senior engineering responsibility or in supervisory or junior management ranks, while those who graduated in the last ten years appear to be generally in staff engineering or junior supervisory positions. This classification is admittedly imprecise because it is difficult to determine from a job description whether duties should be considered of an engineering or management nature - a distinction between the two terms is often over-emphasized. Nevertheless, the trend from technical engineering to management responsibilities with seniority and years of experience is clear in the careers that we have been able to follow."

Jan 1, 1972

By C. H. Tiernon

"This paper was' prepared to emphasize the part that coal washing tables can play in the development of many of the reserves of coking coals in Western Canada_ It covers a brief history of the development of the coal washing table through the present third-generation unit, which suspends from overhead steel beams and is driven by a counter-rotating gear mechanism. The design and operation of this unique table are covered in detail.An analysis of actual operating data is included, with explicit statistical breakdowns of the table products. The data used were actually produced by operating coal companies, and also produced by the United States Bureau of Mines while gathering data for a research investigation. Table feed capacity is discussed, as well as performance criteria and the parameters of relative table performance. Several typical table flowsheets are described, emphasizing the specific reasons for their use. The paper covers the past and present value of the table to the United States coal industry, and makes mention of the newest addition to the family of suspended, multiple-deck, counter-rotating, gear-driven, coal washing tables, the CONCENCO ""88"" Deister table."

Jan 1, 1973

By Alan E. Renshaw

"This paper is a practical overview of ways to reduce cost in the design and operation of an Arctic mine. The economically important issues of the Arctic mine that will be addressed include: permafrost and the active zone in general terms; road building in and over permafrost; Arctic geotechnical mine design considerations; pit dewatering techniques in sub-zero temperatures; and blasting frozen materials with techniques to obtain optimal results. A final section on a few special topics conclude this paper.Although this paper primarily refers to near surface conditions more closely associated to an Arctic surface mine, many of the ideas and techniques contained in the paper also apply to the surface construction of an Arctic underground mine."

Jan 1, 1996

By A. J. Miller

Estimates of interstitial water saturation derived from capillary pres-sure data are compared with residual water saturations found by the analysis of cores out in oil-base drilling fluid. A theoretical explanation for the high-rate of water production from the Bellshill Lake Field is proposed, based on the interpretation of the capillary pressure data.

Jan 1, 1960

By M. E. Charles

The use of water flowing as a lower layer to reduce pressure gradients in petroleum pipelines was investigated using 17.5 deg. A.P.I. Lloydminster crude oil in a 1-inch laboratory pipe-line and a 21h-inch field pipeline. The method was found to be very effective in reducing the pressure gradient below that for the oil flowing alone. The factor by which the pres-sure gradient was reduced varied with the percentage of water added, and in general exceeded 10 for water contents ranging from 40 to 60 per cent. Within this range of water content the pressure gradient reduction factor was independent of the oil flow rate.

Jan 1, 1960

By H. M. Woodrooffe

IT IS WELL KNOWN that chrysotile asbestos from various occurrences exhibits varied physical properties and certain differences in chemical corn position, both of which conditions may have an important bearing on the industrial utilization of the fibre. The usefulness of a harsh fibre in the manufacture of asbestos cement products and of low-iron fibre for certain electrical uses are examples. It is also .possible to obtain a fibre with a texture too harsh and brittle to be of economic value. Much research into the structure of the mineral and to a lesser degree observations relating the water of combination to certain physical properties have ?been reported. This paper is an attempt to show that the pyrolysis of ?chrysotile takes place in three stages and that the conditions of pyrolysis are peculiar to the fibre and may afford some clue to the variations in physical properties of asbestos fibres which affect their utilization.

Jan 1, 1956

By Thomas. Lisa, Mark Coleman

Schenck Process is an established customer-driven solutions provider, utilising its knowledge, expertise and technologies to transform production processes. Operating across several industries Schenck Process have developed quality solutions from their range of equipment to solve problems and fill holes in other people’s processes. In the non-ferrous metals industries Schenck Process have been using their Clyde Brand solutions in Pneumatic Transport to solve problems on smelter sites for a number of years, handling of concentrates, additives and metallurgical dusts. Working alongside clients around the world they have developed a number of dust handling systems for flash furnaces from New Boliden, through Codelco to PASAR. Solving handling issues in dust collection has proved to suit Schenck Process range of equipment well and now a series of solutions are available. Solutions have been developed to handle materials up to 600°C and can convey over 1 km. Conveying to remote location for disposal, injecting directly into a furnace through lances, return to furnace burner feed, or deliver and dose into leaching reactors, Schenck Process are ready to ‘make processes work’. Historic solutions at New Boliden and Codelco demonstrate a range of material application and the long term performance of the equipment. Recent installations at Pasar utilise the Schenck new ProPhaseTM equipment and handle the Waste Heat Boiler and ESP dusts directly and simplify the dust train. The paper will seek to show how this equipment can bring benefit in handling high temperature materials directly and eliminate several traditional steps that are often unreliable. The systems can be paired with Schenck Process new PHASiQTM and STREAMiQTM control systems which are complete PC, HMI, PLC, Interface system with full SCADA, Data Storage and IoT ready remote interrogation and support available. Installed in this challenging environment the systems are ready for smelter use. The systems can be also joined to our new E-nizingTM web portal. A perfect partnership to deliver the trend in ‘Big Data’ while providing visibility and off site support. The paper will show how these systems can deliver reliable equipment and remote support for these often isolated sites as well as delivering rapid return on investment. This paper discusses a step change in simplifying Flash Furnace Dust handling which Schenck believes shows the truth of Schenck Process Solutions claim that ‘we make processes work’.

Jan 1, 2019

By Raymond S. Suglo

Increasing depths of mining coupled with the mechanization of most underground mining operations have led to growing complexities in the mine environments with the production of large amounts of gaseous and particulate contaminants. Over 100,000 lives have been lost due methane gas and dust explosions in coal mine workings in both the US and Canada since 1900 when the methane concentrations exceeded stipulated levels in some workings. There is therefore the need to constantly assess and evaluate the performance of the existing mine ventilation systems to maintain safe and acceptable mine environmental conditions in workings to meet the requirements of federal, state or provincial laws. This paper uses the results of continuous monitoring of methane concentrations conducted in selected development headings in coal mines in North America to assess the effectiveness of existing auxiliary ventilation systems in the control of methane gas concentrations in the headings. The results show that the average quantities of fresh air required to dilute, disperse and remove methane concentrations within set levels of one minute varied from 5.43 m3/s in Heading #11 (Condition 2) to 27.97 m3/s in Heading #10 (Condition 1) and this represented about 12 to 26% of the quantities required to dilute methane concentrations to safe levels within one minute under Condition 1 and 32 to 139% under Condition 2. The average dilution times in the headings studied were less than 8 minutes. The forcing efficiencies of the auxiliary systems in the headings studied ranged from poor to excellent implying that the auxiliary ventilation systems were capable of controlling the methane concentrations below statutory levels but may not be able to cope with large and unusual methane concentrations in the headings. This study is important to prevent methane gas and coal dust explosions in coal mines and thus avoid any loss of lives and property.

May 1, 2001

By P. -Q. Wu

A modified electrochemical noise (EN) technique has been applied to monitor corrosion wear of TiN-coated ASP23 steel and TiN-coated AISI 316 stainless steel sliding against corundum in 0.5 M H2SO4. Experimental results show that the EN technique can sensitively detect potential and current variations during a corrosion-wear process. Corrosion-wear mechanisms of TiN coatings depend on their substrate properties. If the substrate is passive, such as AISI 316 stainless steel, the potential and current variations reflect the properties of the coating. Depassivation and repassivation alternately take place on the tribo-activated wear area during the steady-state phase. If the substrate is active, such as ASP23 tool steel, the electrochemical noise is dominated by dissolution of the substrate at the pinholes and the hydrogen evolution all over the exposed surface.

Jan 1, 2005

By W. Tse, D. Wong

Dense medium separation (DMS) is one of several preconcentration methods used for early waste rejection from run of mine ores at relatively coarse particle sizes prior to additional milling and beneficiation. DMS has been used extensively in the coal, diamond and iron ore industries but lab scale and pilot test work has demonstrated successful separation and upgrading of other minerals such as lead, zinc, copper and lithium based ores using DMS. This paper reviews historical dense media systems, results from the pilot scale Condor DMS system as well as associated laboratory heavy liquid separation (HLS) test work.

Jan 1, 2014

By E. V. Manlapig, M. A. Hampton, M. E. Holuszko

Methanol treatment of ZnS particles has been found to remove slimes and facilitate flotation. The removal of slimes renders the ZnS surface more hydrophobic, resulting in an increase in the hydrophobic attractive force between the particle and bubble. Hallimond tube flotation, induction time measurement and particle-bubble force analysis with the atomic force microscope (AFM) was undertaken to link the beneficial effect of methanol treatment of ZnS particles to their increased floatability.

Jan 1, 2009