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By Richard Stewart

There are highly competitive world markets in most of the minerals being mined today. The high standard of living we enjoy in North America results in ever increasing productivity through mechanization and automation. Conventional underground and open-pit mining practices throughout the world are constantly changing to reflect the engineering advances of our technology. New records in tunneling, shaft sinking and excavating are being established. Larger and faster equipment is in production. Mining operations are being studied in detail to improve materials, methods and machines. Standards and controls are being established to measure the performance of people and equipment. These steps all tend to improve our present performance. In addition to these short-range improvements, however, there are the basic research and applied research studies which are aimed at developing entirely new approaches to our mining problems. Basic research in rock mechanics is coupled with applied research in rock penetration, fragmentation and stabilization.

Jan 1, 1963

By L. Jones, S. R. Lawrence, A. R. Holloway

Whilst dense medium separation is best known for its ability to concentrate diamond and coal deposits, the process is now being employed in southern Africa as a pre-concentration step to improve the economics of platinum group metal and nickel ores. DMS plants built for these industries (such as the 1600tph unit at Tati Nickel, Botswana), are spearheading an expansion in this area by reducing mine and process operating costs yet maintaining economic metal recoveries. This paper provides an overview of DMS technology and examines the economic benefits available to North American operators and projects, with recent case studies as reference.

Jan 1, 2009

By F. N. Smith

The carbon steel casings of Heat Recovery Steam Generators (HRSGs) in a co¬generation plant were found to have developed cracks that originated on the inside surfaces. The HRSGs receive hot exhaust gases from the primary Gas Turbines (GTs), which are fuelled with pipeline natural gas. The GTs was initially operating without any suppression of nitrogen oxides (NOx). After being in service for about two years, some of the cracks were found to have penetrated right through the 1/4 in. thick casings. The casings are fitted with insulation on the inside (hot gas side). Examination of steel samples cut from the casing walls revealed (i) fine cracks propagating through the steel from the inside surfaces, and (ii) the presence of relatively large amounts of nitrate ion on the inside surfaces. It was concluded that the nitrate ions originated from nitric acid that was condensing on the relatively cool walls of the casings behind the insulation. Nitric acid was formed in the GT exhaust gases by the combination of water vapour (formed from combustion of the hydrocarbon fuel and from moisture in the combustion air) and nitrogen oxides (formed from nitrogen and oxygen in the combustion air).

Jan 1, 2005

By Antonius Prayoga

PT Smelting adopted the Mitsubishi Continuous Technology for its copper smelter plant which has been operating since 1998. Through a series of expansion projects, the plant annual production capacity increased gradually from 200,000 to 300,000 tons of copper. There were no significant modifications for the smelter to reach the 50% additional capacity. It was mostly achieved by intensifying the operation of the furnaces by increasing the oxygen content in the furnaces blowing air. Intensive smelting furnace operation caused shorter campaign life of some furnace refractory, especially the melt zone wall on furnace outlet. During each furnace relining, which is done once every two years, severe wall erosion was found. The worst condition occurred in 2007 when the smelting furnace experienced a melt leak through the eroded wall beneath the bath-line coolers. During the 2008 furnace relining, a modification was performed by installing vertical coolers behind the melt zone wall. Additional vertical coolers were installed during the 2012 furnace relining to extend the coverage area. The modification improved melt zone wall integrity significantly by keeping them safely within the two year campaign life. Recently a modeling study was done to estimate the influences of molten waves on furnace wall erosion. The aim of the study was to predict the impact of blowing parameters, such as blowing air velocity, on the melt wave character and wall erosion.

Jan 1, 2015

By D. A. Beattie

Three novel dextrin polymers of varying functional group chemistry but similar molecular weight have been used to depress talc in single and mixed mineral studies. The mixed mineral system was a model sulphide ore consisting of talc, pentlandite, and chalcopyrite. Adsorption isotherms for the three polymers on both valuable and gangue mineral phases were determined to give initial clues as to the ability of the polymers to depress talc. Flotation testing revealed a distinct hierarchy of effectiveness of the polymers in the depression of talc in the single mineral system (MP Dextrin > CM Dextrin > Dextrin TYM), reflecting the observed adsorption affinity and adsorbed amount of the polymers on talc. However, a different order of effectiveness was observed for talc depression in the mixed mineral system (CM Dextrin > MP Dextrin > Dextrin TYM). Competition between the valuable and gangue mineral phases for uptake of MP Dextrin is responsible for its observed decrease in efficiency in mixed mineral flotation. All three polymers were found to be reasonably selective in their action, although at high dosages the polymers began to affect the flotation of the valuable minerals.

Jan 1, 2006

By R. J. Traill

Introduction Following the discovery of high-grade deposits of pitchblende in the Great Bear Lake area of the Northwest Territories by Mr. Gilbert LaBine in May, 1930, samples were submitted to the Mines Branch for examination and investigation as to suitable methods of treatment (1). The purpose of this paper is to present, briefly, the results of the investigative work conducted on the ores and an outline of the methods developed for the extraction of the radium content and recovery of the by-products. The paper is presented in two parts. Part I gives a review of the history of radium production and of the principal processes used in other countries. Part II describes the work and gives the results of the Mines Branch investigation. Part 1-Radium Production In Other Countries Historical Outline Uranium was discovered in 1789, and more than a century later Madame Curie, while studying the physical properties of this element, observed that the ore of uranium exhibited greater activity than the pure uranium com-pounds she had prepared and traced the cause to the presence of a new element which she named radium. Eventually, research proved radium to be a disintegration product of uranium, and always present in uranium ores.

Jan 1, 1933

"The content of production reports has its origins in raw measurements taken in harsh production environments. The ensuing measurement/estimation errors always affect reproducibility such that, regardless of the fact that they are balanced through statistical data reconciliation, reported numbers are simply the most probable values of inferred probability distributions. This has important implications for how metal recoveries should be monitored and reported. Indeed, in a context where many process optimisation activities are based on small improvements in recovery, there should be no doubt that inadequate handling of measurement/estimation errors can easily exaggerate or mask actual changes in process performance. However, estimates of the reproducibility of reported metal recoveries are rarely reported to plant management. This situation persists despite the fact that a code compliant metal accounting system must inform management about business risks related to metal accounting. To this extent, this paper focuses on the continuous management of reproducibility level of metal recoveries in compliance with the best practices. Sensitivity analysis of primary and secondary metal accounting models is performed to show the resulting probability distributions for metal recoveries. Some guidelines are given for designing and managing metal accounting systems capable of achieving and sustaining predefined levels for the reproducibility of metal recoveries.INTRODUCTIONEach and every mineral processing plant produces daily, weekly and monthly production reports in which metal balances for payable and penalty elements are presented. While such production reports are usually consulted in offices, underlying raw measurements are taken in harsh production environments where mechanical vibrations, humidity, corrosion and dust, to name a few, disturb measurement procedures. It is thus no surprise that several authors (Francois-Bongarcon & Gy, 2002; Gaylard, Randolph, & Wortley, 2014; Holmes, 2010; Spangenberg & Minnitt, 2014) have reported pervasive issues related to mass/sampling measurements in the context of mineral processing."

Jan 1, 2016

By P. S. Arthur, G. R. F. Alvear

Development of a new smelting process is risky. Many novel processes in the metals industry failed to fulfil the initial expectations of their inventors. Large sums of capital have been invested in technologies that either didn't provide a satisfactory return on investment, or didn't perform at all, and had to be replaced. One of the keys to success in process development is incremental scale up of the technology, with potential problems being identified and rectified as early as possible. In this way the cost of any rectification that is required can be minimized. The ISASMELTTM process was developed to maturity by Mount Isa Mines through the 1980's and 1990's using incremental scale up. Commercialization only occurred once the process had been proven on laboratory, pilot and demonstration scale over many years. As a result ISASMELTTM technology now operates successfully at numerous plants around the world. The methodical approach to development of the technology has allowed owners to modernise their existing operations or create new businesses with significantly reduced technical risk.

Jan 1, 2011

By Harry J. Cain

Introduction The property of Pioneer Gold Mines of B. C., Limited, is located in the Lillooet mining district of British Columbia, on Cadwallader creek, 54 miles distant by motor road from Shalalth, a station on the Pacific Great Eastern railway. Milling by the present Company was commenced in 1924, a small amalgamation plant, consisting of a crusher, Bryan mill, and plates being operated until 1928. Tailing from this plant was impounded and later treated in the 100-ton continuous counter-current decantation cyanide plant which was erected during 1927-28 and placed in operation during May of 1928. A second cyanide plant, employing continuous counter-current decantation, having a nominal capacity of 200 tons, has been erected during the past few months and was put into operation during September of the present year. The ultimate capacity of the combined units of the present mill has not been determined, but it is expected to be much in excess of the rated capacity. The Ore The ore, as received at the mill, consists chiefly of quartz carrying free gold, with small amounts of pyrite, arsenopyrite, and pyrrhotite in evidence, though probably amounting to less than one per cent of the total. Some gold is very closely associated with the sulphides. The country rock is a basic igneous rock, probably an augite diorite. Near the vein it is highly altered to sericite, which slimes readily on grinding, and does not settle very well. The quartz is of two types, clear and ribbon. In the latter, the ribbons, which are not much thicker than paper, consist of shattered sulphides. In crushing this ribbon quartz, breakage is often along the streaks, exposing these shattered faces to advantage in subsequent treatment. While gold is the metal for which the ore is mined, some silver is also present and is paid for by the mint. It is, however, unimportant from a commercial viewpoint. From the standpoint of crushing and grinding, the ore might be termed 'medium 'hard'.

Jan 1, 1932

By A. Ignatow

"A review is made of some of the principal factors and conditions that are, and will be, important to the over-all market climate for asbestos fibre and for the future of Canada's asbestos industry: - health hazard associated with asbestos exposure;- uncertain international regulatory environment for continued asbestos use;- adverse public reaction to asbestos;- product liability/litigation costs (U.S.A. primarily);- promotion of substitution by governments and asbestos user industries; and- minimal product and market development efforts by asbestos producing and consuming industries.In addition, Canadian producers, who export some 95 per cent of their production, face additional constraints:- dramatically reduced integration with asbestos-consuming industries;- 60 per cent of exports to most rapidly declining markets (U.S.A., Europe);- increased competition from offshore producers favourably located to growth markets in developing countries;- increasing production costs;- a strong dollar;- disadvantageous freight rates; and- loss of price leadership and price erosion.Future market trends, as well as prospects for Canada's asbestos industry, will be projected in this paper.Economic FactorsTable 1 presents asbestos fibre production in all countries for the period 1980-82. In certain instances, e.g. U.S.S.R. and China, these are capacity estimates as production statistics are not officially published. The U.S.S.R, by far, is the world's largest producer accounting for some 50 per cent of world production, though most production is consumed internally or by COMECON countries. It is estimated that some 700 plants produce asbestos-containing products within the U.S.S.R.Canada accounts for some 25 per cent of world production though it ranks first in world trade. Other important producers are South Africa Zimbabwe, Brazil and Italy. Since 1979, Canada's asbestos mining industry has experienced a dramatic drop in production and exports of asbestos fibre, as demonstrated in Table 2."

Jan 1, 1985

By P. Leo

Al-Mg-Si alloys are widely used as medium-strength structural materials; extrusion is the most common processing route. In the present hot deformation investigation of a 6060 alloy, the microstructure of the alloy has been analyzed in the as-cast state, after homogenization heat treatment and after hot deformation by tensile tests in the range 400-490°C and 10-4 to 10-2s-1 on both as cast and homogenized alloys. After deformation the microstructure of the as-cast alloy exhibited cavitation. The flow curves at the lowest test temperature T show a gradual softening after a stress peak, being more evident for the alloy deformed in the homogenized state in association with a high yield stress; at higher T a plateau is attained which is lower as T rises and strain rates decrease. For each fixed T, the ductility decreases as strain rate increases for the homogenized alloy whereas, for the as cast alloy, it rises with strain rate. Constitutive analysis gives Q = 240kJ1mol for the homogenized alloy in agreement with published values; this indicates a more rapid strength decline with rising T than Al, suitable for good hot workability along with the lack of cavitation.

Jan 1, 2011

By J. R. Kish, J. Dabrowski

"The susceptibility to intergranular corrosion modes is a major technical issue preventing widespread utilization of higher strength welded AA7xxx extruded beam profiles, in the peak-aged T6 condition, in automotive bumper assemblies. A study was undertaken to evaluate the relative exfoliation corrosion resistance (ASTM G85-A2) as a function of joint design parameters, namely the base alloy composition, heat-treated condition and beam orientation after exposure to a cyclic acidified salt spray test. This paper documents the major findings extracted from this study.INTRODUCTIONBumper systems play a predominant role in the passive safety of an automobile, since they are one of the main structures for absorbing the collision energy in the event of an automobile crash. Heattreatable AA6xxx-series (Al-Mg-Si) and AA7xxx-series (Al-Zn-Mg) Al alloys, with relatively high strength, toughness, energy absorption, weldability and formability, make it possible to design costcompetitive bumper systems to crush in a controlled fashion. In this context, Cu-lean AA7xxx extrusions, such as AA7003 and AA7108, which exhibit higher strength than AA6xxx extrusion, such as AA6082, represent an attractive light weight material from which to fabricate bumper assemblies (Clausen et al., 2000; Pedersen et al., 2008; Chen et al., 2009).Arc welding is a key joining process for AA7xxx alloys within the transportation industry. A major technological issue preventing widespread utilization of arc-welded AA7xxx joints is the susceptibility to severe localized corrosion (Kent, 1970, Reboul et al., 1985; Holroyd et al., 1987). It generally occurs as exfoliation corrosion within a heat affected zone (HAZ) a few millimeters from the weld bead, or a type of stress corrosion cracking (weld-toe cracking), which initiates at the weld toe and propagates into the interfacial region between the weld bead and the HAZ (so called “white zone”). In addition to the micro-galvanic cell activity induced by the intermetallic compound constituent and strengthening particles present, there is strong evidence that macro-galvanic cell activity between the weld bead and base AA7xxx alloy may be playing a controlling role. Electrochemical profiles taken across fusion welded joints, in cross-section, during exposure to saline solutions suggest that a significant potential difference exists across the AA7xxx arc-welded joint (Shumaker et al., 1967; Grauer and Wiedmer, 1980; Tuck, 1985, Onoro and Ranninger, 1993). These studies consistently show that the HAZ and base alloy are more electronegative with respect to the weld bead (arc-welded with AA5xxx filler wire). Despite this initial important work, the majority of the recent corrosion research effort on welded AA7xxx alloys has focused on the performance of friction stir welds (Lumsden et al., 1999; Wadeson et al., 2006; Hatamleh et al., 2009)."

Jan 1, 2012

By K. A. Natarajan, M. N. Chandraprabha

Selective separation of minerals from complex sulphide ores is a challenging task and it is often difficult to get commercially acceptable individual concentrates by conventional selective flotation using inorganic collector reagents. Microbially-induced mineral beneficiation has proved to be more effective, economically viable and an environmentally benign process for the effective separation of various minerals. Applications of microbially-induced mineral beneficiation are demonstrated in this paper with respect to beneficiation of complex multimetal sulfides. The role of adapted microorganisms and bioreagents in the beneficiation of complex sulphide minerals are also illustrated.

Jan 1, 2009

By M. S. King

"A simple method is proposed for determining the long-term deformation behaviour of evaporites. The theory developed can be tested by measuring the change in diameter as a function of time of a vertical mine shaft opposite evaporite strata. Ultimate shaft closures predicted by the theory agree well with those calculated with the very much more complex theory of Serata (1968), provided that sufficiently high octahedral shear strengths are used in the former.An analysis of measurements made in an isolated opening in a Saskatchewan potash mine shows that the octahedral shear strength of the surrounding potash and halite was approximately 500 psi several years after the opening was mined. This value is less than that deter-mined experimentally for halite by Serata. The same data indicate, furthermore, that the in-situ octahedral shear strength is decreasing slowly with time.The current controversy regarding the actual deformation of evaporites will only be resolved by the cooperation of potash producing companies in releasing data on the long-term deformation of their mine shafts."

Jan 1, 1971

Over five decades ago Kitchener et al. in England and La Mer and Healy in the US were advancing our understanding and application of flocculants, primarily related to water treatment and filtration of sludge. This paper identifies the beneficial uses of flocculants in the mining industry and revisits some less common applications. Flocculants are used in unique ways in the mining industry: (a) to increase the effectiveness of sediment ponds to achieve discharge compliance; (b) to eliminate air emissions and costs associated with concentrate drying; (c) to reduce soil loss by applying a flocculant to erodible soils, and reducing wind and water erosion; (d) to remove/thicken metal precipitates in acid rock drainage treatment; and (e) to enhance clarification and thickening in mineral processing. The mechanism of how flocculants, coagulations and potentially-determining ions function is described and how their use can be controlled and optimized. The potential toxic effects of flocculants and coagulants when used to achieve effluent permit discharge compliance for suspended solids is discussed. A review of numerous best management practice (BMP) guidelines for the design and operation of sediment ponds treating mine site runoff to remove total suspended solids (TSS) and turbidity revealed an absence of a predictive methodology to address regulatory discharge compliance for TSS concentration, turbidity and flocculant-induced toxicity. An essential component of pond design is the need to determine whether flocculants and/or other settling aids are required based on the site-specific soil particle size distributions upslope of the pond. Procedures are provided to predict the need for settling aids and estimate pond discharge quality and downstream impact for TSS, turbidity, toxicity and sub-lethal toxicity. The need to develop BMP guidelines are discussed for (a) the application of flocculant to surface soils to reduce erosion, (b) the application of flocblocks to increase the ?sediment control? aspects of erosion and sediment control, as part of the mine site erosion control plan strategy and (c) the application of flocculant to silt socks to treat mine site runoff.

Aug 1, 2013

By P. Mottahed, E. De Souza

One of the major unsolved problems of safe, economical roof support in the evaporite industry has been that of obtaining and maintaining anchorages in relatively soft rock. This is due to the viscoelastic and viscoplastic behaviour of salt rock and associated deposits. This paper introduces a low-cost, yieldable support mechanism, consisting of a system of buckling disks, which provides viable solutions to dynamic support. The yieldable support system offers a number of advantages in comparison with existing dynamic support systems. It is characterized by its simplicity in design and installation, repeatability in behaviour and cost effectiveness. It also has the added advantage of providing the operator with a means of assessing support behaviour and ground performance by direct visual observation of changes in disk shape. Thus, the system can be utilized as a warning mechanism of ground stress and support load conditions. Such system not only provides a feasible and more effective rock mass stabilization strategy but improves mine safety.

Jan 1, 1999

By T. D. Traubert, J. T. Dietz, D. Catena

"Canadian process industry experts have often observed the strong trend for U.S. industrial safety and environmental laws to creep across the border. These experts will be interested in new United States (OSHA) regulations (29 CFR 1910.119), and anticipated new U.S. Environmental Protection Agency (EPA) regulations that will require over 28 000 U.S. refineries and chemical plants employing more than three million workers, to begin a comprehensive Process Hazard Analysis (PHA) of these complex plants immediately. Impending EPA regulations are expected to expand these efforts and add process Hazard Frequency and process Hazard Consequence reviews for many additional industrial locations.These regulations were created to reduce catastrophic industrial accidents, and emergency releases of hazardous chemicals which endanger employees, the public, and the environment.Accurate, and field verified Piping and Instrument Diagrams (P&IDs) are essential to permit a meaningful Process Hazard Analysis or emission release to be done. Today accurate P&IDs often do not exist. Many companies that have started to update their old P&IDs have found the process to be far more difficult, time-consuming,and expensive than they ever thought.This paper describes a new technique of computer drawn ""Intelligent"" P&IDs that can make a Process Hazard Analysis less expensive, more accurate, easier to perform, and provides lasting benefits to the plant owner long after the PHA has been completed."

Jan 1, 1993

By F. A. Forward

"NINETEEN sixty-six is a year of unusual significance in our Institute and in our country. It marks two-thirds of a century of service by the Institute to the people of the mineral industry and two-thirds of the century that Sir Wilfred Laurier said ""belongs to Canada."" As we meet here today within the historic walls of Canada's oldest city, a city that looks back on three hundred and fifty years of progress, I am reminded that it is almost a third of a century ago -in April, 1934 -that here in Quebec I first attended an Annual General Meeting of the Institute. It occurred to me that it might be appropriate to examine briefly the change that the middle third of this century has brought in the affairs of the mineral industry and, with some trepidation, to consider the prospect for the third that lies ahead.Opinions differ as to the relative importance of factors that have been responsible for the expansion and growth of Canada in its first hundred years. Some will say that it has been due to the abundance and fertility of agricultural land, others to the early enterprise of the railroads, and financiers believe that the banking system has been a major factor; -the fisherman -the forester -the teacher -each has his own view. I suspect, however, that most of us here would subscribe to the thesis of T. A. Rickard -miner, author, imperialist -who wrote, a gene-ration ago, ""Trade follows the flag, but the flag follows the pick,"" and thus agree that the finest contribution to progress, to wealth, to extension of frontiers and to inter-national trade has been provided by the mineral industry."

Jan 1, 1966

By T. H. Wilson

In 1901, the Crow's Nest Pass Coal Company, Limited, began producing industrial coke in 212 beehive ovens at Michel colliery. By 1908, 486 ovens had been installed and in that year 147,623 tons of coke were produced. Coke manufacture has been continuous from 1901 until the present time (1946), with total production of 2,795,402 tons. At present writing, only 100 beehive ovens are operating and production is reduced to 1,800 tons per month, due to the shortage of suitable labour. These ovens are drawn by hand, on contract, and the workmen are exposed to considerable heat. A man draws three ovens in eight hours, thereby producing approximately 1072 tons of coke per day. In addition to the inefficient and costly method of drawing coke in beehive ovens, tremendous losses are experienced in the wastage of gas and tar, which are driven off into the atmosphere. Also, the yield of coke per ton of coal fed to the ovens is low as part 9f the carbon is utilized in producing heat to carbonize the remainder of the coal. A recovery of only 55 per cent of the carbon, as coke, is obtained. The coking process takes place from the top of the charge, which is 21/2 feet deep, downward to the floor. Six and a half tons of coal are charged and 3.6 tons of coke are drawn from the oven after 72 hours' carbonization. The beehive ovens using Michel coal produce a very hard and tough coke, large in size and of silvery appearance, which has served the requirements of both foundry and smelter for many years. In 1938, the Company made a careful study of coking processes with a view to introducing a more economical method than beehive ovens and one that would be less dependent on skilled labour, the supply of which was rapidly diminishing at that time. Various methods of by-product coking were investigated, and it was decided that the Curran-Knowles process offered the greatest possibilities because of the low capital investment in relation to output and also because the horizontal oven design was suitable for an expanding coal. Consequently, a test on Michel B seam coal, supervised by Mr. E. Burrough, of the Fuel Research Department, Ottawa, was run in the Curran-Knowles plant at West Frankfurt, III. The results of this test led to the construction of a ten-oven battery of 32 ft. 6 in. by 8 ft. 3 in. Curran-Knowles ovens at Michel, which were completed in November, 1939. This battery was built as an experimental unit, with provision for an additional ten ovens if the coke proved satisfactory for the market. In 1942, an expanding coke market led to the construction of a second battery of ten ovens, which were completed in April, 1943.

Jan 1, 1947

By H. Arima, Y. Kudo

In general, the iron content of zinc leach residue produced by sulphuric acid leaching from calcine is disposed as jarosite or goethite into a tailing dam. More recently, these iron residues have been treated pyrometallurgically to avoid waste disposal. The Iijima refinery selected a different zinc leach residue treatment process for iron control when it was established in 1971. The Iijima refinery is the only plant in the world that has processed a zinc leach residue by the combination of SO2 pressure leaching and O2 pressure hematite precipitation. The process enhances zinc recovery and recovers gold, silver, copper, lead and rare metals in saleable by-products. This paper focuses on the two stages of autoclave application in the zinc leach residue treatment process. The detailed flowsheet and recent advancements to improve the quality of by-products are discussed.

Jan 1, 2004