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By J. G. Ross

IN the paper entitled Block Caving at the King Mine (1), which was presented at the Annual General Meeting held in April, 1934, at Quebec, it was pointed out that, owing to certain conditions and financial restrictions, it was advisable to provide a temporary shaft. This was raised from the )00-ft. level to the bottom of the pit, and a 45-degree incline track was constructed up the face of the pit to surface. The temporary shaft and incline were within the ore-body, but were to be used only until such time as the new shaft-the subject of this paper-could be sunk and made ready for operation. After a careful study had been made of all available information pertaining to the ore-body, including examination of diamond-drill core records and geological data, a shaft location was selected well outside the ore-body. Further, since the crusher and dryer buildings are located over part of the ore-body, it was necessary to plan the removal of these buildings and to construct a new crushing and drying plant. This, and the new shaft, must operate in conjunction with the present mill and rock storage bin, which would continue robe used as formerly. No part of this programme, with the exception of drifting toward the shaft site, was started prior to 1937. More than usual detail on technical features is given in this paper in the hope that some parts of it may be of assistance to other members of the Institute who have to undertake somewhat similar work. The engineering and operating staff designed and supervised the work, while at the same time carrying on regular production in four mines at the rate of 12,000 tons of rock mined per day, the output at the King mine being at the rate of 140 tons per hour. No additional engineers were required.

Jan 1, 1939

By A. M. Elmahdy, T. Hirajima, M. Farahat

"Separation of molybdenite from chalcopyrite is mainly achieved through flotation technique to raise their grades up to 25% to be extracted in smelters. However, molybdenite recovery and grade obtained from this process is not satisfactory in most cases due to the natural hydrophobicity of both minerals. The influence of conventional heat treatment on pure chalcopyrite and molybdenite minerals was investigated. X-ray diffraction, TG-DTA and XPS techniques were applied before and after heat treatment. The results showed phase changes for both minerals. Magnetic separation experiments of single and mixture of both minerals at several magnetic intensities were made. For single mineral experiments, 100% molybdenite recovery was obtained at all experimental conditions as non-magnetic fraction whereas ca. 100% chalcopyrite recovery was achieved under certain conditions. In case of 1:1 binary mixture, 87% and 83% molybdenum and copper recoveries, respectively, were obtained. The increase in chalcopyrite magnetic recovery is related to the formation of more magnetic phases as confirmed by characterization techniques.The objective of this study is to increase the magnetism of chalcopyrite to make its separation from molybdenite by magnetic separation possible and to understand the mechanism behind it. These results indicate that it may be possible to upgrade molybdenite ores using heat treatment followed by magnetic separation to the required grade by smelters which is difficult to attain by froth flotation and the other techniques."

Jan 1, 2016

By R. Baker

A novel electrochemical half-cell and corresponding working electrode were designed to evaluate the electro-catalytic activities of catalysts in an environment close to that of an operating proton exchange or polymer electrolyte fuel cell (PEMFC). Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques were employed using the novel cell to characterize various methanol electro-oxidation parameters that contribute to the overall reaction on a fuel cell anode. The effect of temperature on methanol oxidation kinetics was examined in the potential range of 0.31 to 0.65V (vs. NHE). The data was collected in the temperature range of 20 to 80°C. Based on the experimental analysis and literature data, an equivalent circuit model (ECM) for methanol oxidation was proposed and was used to fit the EIS experimental data. The experimental data and ECM electrochemical data was used to extract electrochemical kinetic parameters for methanol oxidation such as the exchange current density, Tafel slope, and energy of activation for the reaction. Kinetic data, especially at different temperatures, is very limited in the literature.

Jan 1, 2005

By Mark Sherman

"One of the main functions of a process technology and engineering services provider is to select grinding equipment that will meet the client’s throughput rate target. Prudent risk mitigation strategies would suggest that throughput rate estimates be cross-checked using a variety of techniques.Whilst some comminution circuit designers have estimated specific energy requirements via the manipulation of the Bond specific power equation e.g. Barratt’s Grindpower and OMC’s FSAG approach, other designers have opined that the Bond Indices have no role to play in the calculation of SAG mill specific power. As a result, they have developed their own specific energy estimating methodologies, e.g. SMCC’s Drop Weight based power methodology, SPI, SAGDesign, etc. Each method has its supporters and its critics.The challenge facing the engineering provider is how to nominate an SAG mill based circuit throughput rate estimate when faced with significantly disparate specific energies calculated by the different methodologies. This challenge is exacerbated via the continuing evolution of contemporary circuit configurations such as two stage pebble crushing some of which incorporate HPGR technology as the second stage of pebble crushing.The methodology presented in this paper shows that the Bond Indices are an excellent tool for estimating the specific energy requirements for SAG mills in SAB, SABC and SSS circuits. The method accommodates primary crushed feeds, partial and or fully secondary crushed SAG mill feeds, and emulates the impact of pebble crushing on SAG specific energy. As a result, the new Bond Index based method has provided an additional tool for increasing Fluor’s confidence when predicting SAG mill based circuit throughput rates. Based on this outcome, the author proposes that the decades old conundrum of using Bond Indices to calculate SAG specific energies for SAG mill based circuits has been solved."

Jan 1, 2012

By T. Scully

Since early days in coal mining, it has been known that some coals and the carbonaceous materials associated with them will heat and fire spontaneously. Many theories have been advanced to account for this phenomenon, but it is only within comparatively recent years that any scientific research has been carried out to determine the causes of this heating, the conditions which bring about its occurrence, and the reason why different coals heat with a varying degree of readiness. So far, this research has not cleared up these points entirely, but a great advance has been made in our knowledge of the matter. In general, any coal will fire spontaneously, although with a varying degree of readiness, provided conditions for its doing so are favourable enough. These conditions are that the coal must be in a fine state of division, that sufficient oxygen must be present for rapid oxidation, and that the air current passing must be so small that it is insufficient to carry off the heat produced by this oxidation. Many other minor factors, however, contribute to bring about spontaneous heating, either by producing initial heat themselves or by inducing the other major conditions.

Jan 1, 1931

"Acid resistant brick lined autoclaves and related vessels are utilized in pressure oxidation for the recovery of gold, copper, and other metals. The combination of the corrosion resistant membrane, acid resistant brick, mortar and steel shell is a composite system that requires a sophisticated stress analysis. In order to obtain meaningful results both the model and physical properties of the materials must be carefully selected. Evaluation of the calculated results requires an understanding of both the failure mechanisms of ceramics and experience with the performance of existing lining systems.INTRODUCTIONAcid brick lining systems are used in pressure oxidation autoclaves and related vessels to provide thermal and mechanical protection for corrosion resistant membranes that are applied directly to the interior of the vessel shell. The acid brick and mortar must be resistant to the process conditions and must provide a mechanically reliable structure.The construction of lined vessels incorporates a wide range of materials that can include the carbon steel vessel, austenitic weld overlay, lead lining, organic membrane, ceramic brick, mortars and other alloy components. The physical properties of the materials can vary by orders of magnitude and when combined in the construction of the lined vessel create a complex composite structure. The materials may be bonded together or act independently of each other. Stresses are induced into the lined vessel include pressure, thermal expansion, chemical expansion and mechanical loads.The complexity of these systems makes it is very difficult to account for all of the variables in the structural analysis of lined vessels. Historically calculations were simplified and designers primarily relied on experience with previous applications.The greatly improved tools for Finite Element Analysis (FEA) available today allow for detailed calculation of the stresses imposed on the vessel shell and lining. Koning & Lauzon (2004) presented a paper on design fundamentals including a discussion on the application of FEA methods at Pressure Hydrometallurgy 2004 in Banff. When a designer carefully constructs a model and selects the correct materials properties for the calculations, meaningful and useful results can be achieved."

Jan 1, 2012

By W. G. Campbell

"The region discussed comprises approximately eight million acres spreading across the Arctic Circle in Yukon and North West Territories.Encouraged by four years of surface geological and geophysical work, which strongly suggested that suit-able conditions existed for the entrapment of oil and gas, a decision was reached to drill. In due course two holes were drilled; Eagle Plains No. 1 drilled to 9589 in 1957-8 and Western Minerals Chance No. 1 spudded in 1959 is being deepened this year.Thick sections of sedimentary rocks occur on both sides of the Richardson Mountains, however, most of our activities have been concentrated to date on the west side in the Eagle Plains basin. Here are found stratigraphic units ranging from Precambrian to Tertiary age. The drilling of the two exploratory wells proved the presence of these strata at depth and have confirmed the presence of promising structures. A geological cross-section across Eagle Plains presents an interpretation of these conditions.Physical and engineering aspects of exploration in the northern Yukon and North West Territories are de-pendent largely upon seasons and transportation. Reconnaissance gravity and surface geologic mapping by air presents no serious problems. However, seismic operations on the ground are greatly affected by the season, presence of permafrost and mobility of equipment.The actual drilling of the hole may well be the simple part of a wildcat undertaking once equipment and supplies are on location. Over-all planning, assembling supplies, transporting equipment and personnel seems to be the real job. Serious consideration must be given to per-ma-frost effect in the drilling pro-gram and on surface installations as well.Programming for -the various exploration activities should be under-taken well in advance of the actual doing. Considerable extra costs may be the results of crash programs. Costs are high, and the rewards uncertain. Economic evaluation is based •on the long term outlook."

Jan 1, 1960

By S. Fahland, P. Vogel

"The Gorleben salt dome has been investigated since 1979 for its suitability as a repository for the disposal of high-level radioactive wastes. The geoscientific surface exploration was followed by underground exploration of the site beginning in 1983: underground excavation work included the sinking of two shafts from 1986 to 1994, the excavation of the infrastructure area and of drifts located in the first exploration area EB1 within the following years. The exploration was interrupted for ten years from 2000 to 2010 as part of a moratorium. After the expiry of the moratorium in March 2010, the geoscientific underground exploration at the Gorleben site was resumed. The investigations were interrupted again in autumn 2012 due to a political decision. The exploration programme included extensive geoscientific investigations: geological exploration, geophysical investigations, mining exploration and mining observation, laboratory tests, in-situ geotechnical measurements, geological modelling and numerical model calculations. To analyse and interpret the results of the in-situ measurements and mining observation geomechanical, thermal and thermo-mechanical model calculations were carried out. One of the main elements of the in-situ geotechnical investigations were high-resolution geothermal measurements performed in boreholes used for geological exploration and geotechnical tests.The geothermal measurements are used to evaluate several geotechnical findings, e. g. drift closure, rock deformation, stress change, and are completed by thermal model calculations to analyse and interpret the results of in-situ measurements and mining observation. The model calculations have been carried out using the special purpose JIFE code. To consider the whole exploration mine with the adjoining host rock as well as the successive excavation of drifts and boreholes in detail a three-dimensional finite-element model was developed. The model calculations are used to analyse the cooling-off of the surrounding rock of the drifts caused by ventilation. The cooling-off of the surrounding rock is an ongoing process affecting the results of further geotechnical measurements in the near field of the drifts. To predict a realistic time and space dependent distribution of the temperature field of the host rock within the exploration area which is influenced by ventilation thermal model calculations are necessary. Comparing the calculated temperature field with the in-situ determined rock mass temperature field within the exploration area EB 1 the results show a sufficient agreement. Furthermore there is very good correspondence, both qualitatively and quantitatively, between the experimental and the calculated findings regarding the temperature profiles including the effects of excavation and ventilation of the drifts."

Jan 1, 2015

By John A. C. Fortescue

Details of the interactions between the environment and the growth of terrestrial plants may be complex and difficult to study. This paper focusses attention on some of these complexities by means of six examples, each of which provides information on an aspect of the interaction between the growth rate of plants and the chemistry of the environment. The relationships which exist between the information obtained from these examples and the concepts of "holism" and "transfer rate problems" are pointed out and the importance of long-term biog•eochemical studies in Canadian environments is stressed.

Jan 1, 1971

By M. Elmadagli

Wear mechanisms of two commercial aluminum alloys, namely a spray formed and extruded Al-25%Si alloy, and a sand cast A390 alloy (18.5 %Si) that are known to be successful in cylinder bore technology were studied to have a better understanding of the requirements for wear resistant aluminum alloy design. From durability point of view these alloys are known to be successful for engine bore applications. It is interesting to compare the wear mechanisms in these alloys because they have significantly different silicon content and microstructures, and were produced using different techniques. The wear tests were done using a block-on-ring configuration, in controlled air atmospheres (5 % relative humidity). In spite of the differences in silicon content and microstructure, the wear mechanisms were similar and consisted of formation and destruction of hard tribolayers that are either formed by either mechanical or chemical interactions on contact surfaces. The differences in the wear rates between the two alloys arose from the differences in the hardness of the worn surfaces, and the alloy's ability to sustain the tribolayers on the worn surfaces.

Jan 1, 2004

By A. Scheltema Beduin, H. Oterdoom, A. Haaks, C. Kempe, A. Liedtke

"For the Kazchrome DC Ferrochrome plant, SMS-group specifically designed an electrode column that would minimize downtime. Special features include the possibility for on load electrode jointing, on load slipping, and back-slipping. Electrode consumption is strongly related to furnace load and impedance, and is very low at high loads, which makes the graphite electrode an alternative to consider even in AC applications. The electrode could also be applied in other DC applications, as for example TiO2 slag, the novel Conroast process, or (twin) DC FeNi furnaces, and could possibly be installed during bigger shut downs. This paper will describe some of the design considerations and operational performance data on this novel column in the FeCr industry that could also be of interest for the FeNi or PGM industry if these would continue to develop towards DC technology.INTRODUCTION Every DC furnace has a cathode and an anode. The anode applied is commonly known as the Concast design, though the original design was by ABB who handed it over to Concast, subsidiary of the SMS-group. Some well-known DC furnaces outside the steel industry where the Concast bottom has been installed are listed in Table 1 as well as a few other key design features.Sidewall cooling and some other data have been left out for reasons of space, and being a lesser relevant design feature to this paper. HES stands for Hollow Electrode System, in which feed is charged through an electrode. Table 1 is built up chronologically according to first start-up date. Below comments are given to briefly explain some of the columns in Table 1: •,“Arm” in the “Cathode” column means that the design of the cathode holding and regulating mechanism consists of an electrode arm as depicted in Figure 1. •,Charging is relevant as some operations started with HES charging, whereas recently most new operations have started without HES but only charging chutes, of which at least some are close to the electrode and possibly others installed closer to the sidewall. •,“Dome” in the “Roof” column means that the design of the roof involves a center piece that can be exchanged if worn. •,The optimal roof design still seems to be a topic of debate, where no design is without problems."

Jan 1, 2017

By L. Price, R. Hortie

Movement of ore and waste from the Hilton Mines pit is accomplished by truck haulage. With the aim of reducing costs, a study of truck fleet replacement was initiated. The study included on-site short-term tests and longer-term rental purchase agreements for haulage trucks. The operation and maintenance characteristics of different trucks, along with projected haulage conditions, were used to prepare cash flows, from which the most advantageous trucks were selected. The results of the study and implementation of the recommendations gave a cost saving greater than had been estimated. The study also indicated areas where improvements could be made, and resulted in much more attention being paid to road conditions, the training of operators and mechanics, and the development of a practical preventative maintenance scheme.

Jan 1, 1971

By K. G. Baxter, D. G. Dixon

The Sepon process plant utilises an autoclave to oxidize a flotation concentrate containing pyrite, residual copper minerals, and sulphur. The concentrate is produced from the residue of a preceding atmospheric copper leaching circuit. The function of the autoclave is to provide iron and acid for that atmospheric copper leaching circuit. The key issues in the operation of the autoclave are to maximise the production of acid and ferric ions and to avoid scaling issues related to sulphur balling in the autoclave. Scale control in the autoclave was examined using various dispersants and residue recycle without success. Operation of the autoclave at high temperature and high acidity addressed the scale issue through rapid oxidation of the sulphur and produced a ferric sulphate precipitate in the residue that could be re-leached to provide ferric iron. This paper presents the development steps followed, through batch and continuous piloting that resulted in an autoclave circuit design that addressed the above process requirements. Following definition of the process design basis, modelling of the autoclave operation was carried out to assist with engineering design. The model included thermodynamics and kinetics of oxidation of pyrite, elemental sulphur and covellite and also considered gas/liquid mixing, oxygen solubility as a function of temperature and solution composition, ferrous to ferric oxidation, gangue reactions with acid and precipitation/re-dissolution of basic ferric sulphate and alunite.

Jan 1, 2004

By Raj Thamburaj

"Over the last few decades, the emphasis on affordability and reduced cost of ownership has necessitated the development of innovative processes to carry out repairs in aero engine components. Conventional weld and braze repairs have evolved into advanced, sophisticated processes using state of the art knowledge in lasers, robotics and materials technology. This paper illustrates past and present scenarios in an attempt to illustrate progress that has been made in this area. The problems encountered in the past have been detailed along with the solutions that have been developed and commercially implemented to address these issues. Apart from technical progress, this presentation also addresses the progress made in business approaches and in Certification/Regulatory issues surrounding aero engine repair. Progress in Technology Repair technologies have also been the embryo from which new and revolutionary manufacturing technologies have evolved as well. Electron Beam Free Forming and LENS are examples of how a completely new manufacturing concept can evolve what was originally only a process to join metals. The current and future potential of these spin offs is discussed providing examples of application. While several problems have been solved over time with the implementation of advanced repair technologies, the demands of the industry have created new challenges. The paper describes these issues, outlines potential solutions and discusses the future of repair technologies in terms of the far reaching influence it is sure to have in design, manufacturing, maintenance management and life extension. Progress in Business Trends.Business approaches to repair and maintenance have also gone through considerable change with the introduction of ""Power by the Hour"" and other similar arrangements between the companies responsible for engine overhaul and the end-users. Program Based Logistics (PBL) is yet another innovation to provide a win-win situation for the repair service provider and the end user. This paper traces the development of these business initiatives and highlights successful applications. Progress in Repair Certification, Regulatory Issues.Understanding of the issues surrounding certification of repairs has also evolved with time and regulatory issues have been clarified considerably. Procedures for analysis and testing are much clearer and ""Check Lists"" are being drafted for certifying repairs on various engine components. The PMA phenomenon has added yet another dimension to the issues regarding certification and these are discussed as well."

Jan 1, 2010

By Douglas H. Brown

Cadmium and other 'minor' metals in Canada tend to remain inconspicuous given the prominence of the country's massive production of other minerals. This same reality is reflected in the accuracy and deficiency of quantitative data concerning the sources of supply and demand for these metals. It is the intent of this paper to identify the nature of some of these difficulties and to reconstruct a more accurate description of Canada's production and consumption of cadmium, based on the results of recent surveys undertaken by the Mineral Policy Sector of Energy, Mines and Resources Canada and Noranda Sales Corporation Ltd.

Jan 1, 1978

By R. Krentz, P. D. Cordingley

The nickel-cobalt sulphides produced from limonitic laterite ores by Moa Nickel S.A. in Cuba are refined at the Corefco nickel-cobalt refinery in Canada. Major changes to the refining process were required when the Moa sulphide feed, with its unusually high cobalt content, was introduced in the early 1990's. In the period 1994 to 2005 the production capacity of the refinery has increased dramatically to match increases at Moa, and significant process improvements incorporated. The process flowsheet consists of the original ammonia leach process, optimized for cobalt chemistry and overall leaching capacity. Extraction of metal values is followed by the unique nickel-cobalt separation technology, in which most of the cobalt is separated from the ammoniacal nickel sulphate leach solution by precipitation as a nickel-cobalt hexammine salt. This salt is refined from a Co:Ni ratio of 1:1 to over 10,000:1 by selectively leaching nickel, redissolution and recrystallization in ammonium sulphate solution. Nickel and cobalt are recovered using the well-known Sherritt hydrogen reduction technology. This paper reviews the chemistry described above, examines some of the changes in operating conditions made over the years and highlights some of the recent physical changes made to the refinery.

Jan 1, 2005

By David Scott, Denis V. Lachance, Daniel Marcotie

"LocationThe Heath Steele mine is located 50 km northwest of Miramichi, New Brunswick.Brief DescriptionHeath Steele is a 2700 t/d, copper-lead-zinc operation which employs conventional crushing, grinding, and differential flotation.HistoryThe Heath Steele mine is located in northeastern New Brunswick approximately 50 km northwest of the city of Miramichi and 65 km southwest of Bathurst. The massive sulphides containing ore values in zinc, lead, copper and silver were discovered in 1953 as a result of a joint venture between the American Metal Company and the International Nickel Company of Canada. The discovery was named after Mr. Heath Steele, manager of exploration for Amco at the time of the discovery.Mill production began in February 1957; however, the mine was forced to shutdown in 1958 due to depressed metal prices and metallurgical problems. It was re-opened in 1962 and milling operations resumed at 725 t/d until 1968 when the milling capacity was boosted to 1450 t/d and then to 2700 t/d in 1969.OreThe main ore zones are massive sulphides with very fine mineral grain. The chalcopyrite, galena and marmatitesphalerite occurrences are finely disseminated.Liberation is accomplished by grinding to 68% to 72% <400 mesh. Average mill feed assays are 0.8% to 1.2% copper, 1.8% to 2.5% lead, and 5.5% to 6.5% zinc, with 60 to 75 g/t silver."

Jan 1, 2000

Up to thirty years ago, coal preparation in western Canada, except at four plants, had not included actual coal washing. The exceptions were at Nanaimo and Royston, B.C., where tub washers and wet tables were in use; at Hosmer, B.C., using. Robinson cones; and at Leitch Collieries, Passburg, Alta., using a feldspar jig. The two last named collieries had a short life and were not operating in 1920. The industry was divided, as at the present day, into two sections, steam (bituminous) coal and domestic (largely sub-bituminous) coal, the first generally supplying industrial needs and the second householcl and other heating requirements. The two sections overlap to some small degree today as prepared sizes, chiefly stoker, and briquettes, from steam coal are shipped for house-hold use, and domestic slacks are used in certain industrial plants. The .domestic operator, for reasons shown later, was not primarily concerned with actual coal washing as a phase of coal preparation, and bent his efforts to improvement of screening and loading plants, with hand-picking of coarse sizes. The bituminous operator, on the other hand, felt it necessary by 1920 to consider coal washing. When the mines were comparatively young, coal quality could be controlled to a considerable degree by selective mining, by leaving behind some of the seam or by-passing districts in a mine where the coal was of inferior quality to that in other districts. This obviously had its limitations, and so the next step was coal washing.

Jan 1, 1952

By H. Wotruba, L. von Ketelhodt, M. Kowalzcyk, M. Robben

ABSTRACT Decreasing reserves, water shortages, increasing energy costs, and environmental and social constraints are challenges to the gold mining industry that must be met with innovative machines and methods. This paper introduces the principles of sensor-based sorting and installations that demonstrate the technical and financial viability of the method. The scenarios discussed highlight the potential and advantages of this dry processing technology that requires little infrastructure. Case studies are presented for different ore types using optical- and X-ray transmission–based sorting. Current research is discussed in terms of the potential of near-infrared spectroscopy and X-ray fluorescence sorting for gold applications.

Jan 1, 2013

A study was made to determine the effect of increasing concentrations of dissolved oxygen on the floatability of galena pyrite and chalcopyrite. Adsorption, flotation and contact-angle tests were done in deoxygenated, in air-saturated and in oxygen-saturated solutions. The results showed that the adsorption of collector increased as the concentration of oxygen increased. Adsorption followed the exponential law r = kC'/"• Discontinuities in the curves were observed after the adsorption of several monolayers of collector. Although adsorption increased with increasing oxygen concentration, the floatability of the pyrite minerals did not increase, because oxidation had adverse effects on the floatability of these minerals. The floatability of galena was maximum in oxygen-saturated solutions, pyrite was depressed and chalcopyrite was also slightly depressed. Contact-angle tests proved that a bubble could not be attached to large flat surfaces in deoxygenated solutions, because sufficient surface free energy was not available for adhesion after the deformation of the bubble. In the presene of air, all the minerals yielded the same maximum angle of 72 degrees, characteristic of isopropyl xanthate.

Jan 1, 1970