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By T. P. Weldum, W. Conger

"These studies address the relationship between mill media sizing and its grinding efficiency. Starting with the results from a review of the literature, the issues of initial media sizing for a new ball milling circuit, and then optimal media sizing for an existing milling operation, were studied. The Functional Performance parameters “Mill Grinding Efficiency” and cumulative “Mill Grinding Rates” from both plant and test-scale equipment were used, and provide valuable new insight into this topic. A plant media sizing diagnostic tool is presented, as are newly developed testing equipment and evaluation methods, and recent case studies.REVIEW OF MEDIA SIZING LITERATURE For a plant metallurgist to answer the question “How can I maximize plant profit by manipulating this grinding circuit variable?” she must know what effect the variable has on grinding circuit efficiency. Despite the significant cost of grinding media and its potential effect on production capacity, the ‘best’ media sizing remains ill-defined for any given ball mill circuit in the industry today. The underlying reasons for this will be discussed. But the importance of this issue drove Metcom and its industrial partners to take on the challenge of how to engineer the ball charge for an existing grinding circuit. In the absence of any proven method, the first step was a review of the literature. Sponsored by Cleveland-Cliffs, Inc., a broad review of the literature was undertaken, producing “The Effect of Media Sizing on Ball Milling Efficiency” (McIvor, 1997). Among hundreds of publications that were reviewed that discuss the topics of media sizing or wear, forty-five were studied in detail. These were grouped into: plant experiences; laboratory and pilot plant investigations; media wear studies; population balance modeling studies; and general papers on ball milling which included the topic of media sizing. The reader is encouraged to refer to that review. The findings remain unchanged, although some relevant papers have been written since (e.g. Staples et al, 1997; Banasi et al, 1999; Orford et al, 2006; LaMarsh, 2015). The main findings of the review were as follows:"

Jan 1, 2018

By S. Mostaghel, Fariba Azgomi, Steven Goodman, M. Oliazadeh

"It is known that copper loss to the slag phase can be in the forms of chemical dissolution and mechanical entrainment. The contribution of each mechanism to the total Cu-loss depends on different parameters and may vary significantly. To reduce emissions to the atmosphere and to shorten the converting cycle, most industrial processes are aiming at production of high matte grades. Increased oxygen-to-sulfur potential, required by these processes, results in a highly oxidized slag, which in turn leads to an increased concentration of the chemically dissolved copper in the slag phase. Hence, slag cleaning processes are becoming increasingly important for economic viability of the smelting operations. Hydrometallurgical, pyrometallurgical, and mineral processing routes have been used for copper recovery from slag. The current article reviews a trade-off study evaluating two of the commonly used methods (namely flotation and electric slag cleaning furnace) by comparing the technical pros and cons, operability/maintenance requirements, and capital/operating costs of the operations.INTRODUCTIONLarge volumes of smelter and converter slags are produced by copper smelters around the world. It is estimated that for production of each ton of metal 2.2 tons of slag is produced (Gorai, Jana, & Premchand, 2003). Considering the current pressure on the mining and metals industry for “zero-waste, sustainable and environmentally friendly” extraction of metals, it is absolutely essential for metal producers to improve their efficiencies in order to remain competitive. To meet these objectives, almost all metal producers, from steelmaking plants, ferroalloys, base and precious metals producers, are trying to reduce their metal losses to the slag phase. In particular, copper producers are aiming to produce higher matte grades in their smelting furnaces to reduce the converting time and improve their overall throughput. Copper smelters need to minimize their copper/precious metal losses to the slag phase before final landfilling/use of slag. The current article, therefore, briefly reviews the copper loss to the slag phase, methods of metal recovery from the slag and then presents a trade-off study conducted for a green field flash smelter of the sulfide concentrates. A comparison was made between two of the major process routes for metal recovery from slag, namely slag cleaning furnace and flotation."

Jan 1, 2016

By G. J. Heferen, A. Pranowo, N. J. Aslin, P. O. Eriksson

Glencore Technology (GT) has over four decades experience supplying stainless steel cathode plates (“cathode plates”) to the electro-refining and electro-winning industry. Cathode plates are typically the single biggest capital investment in a refinery. Refineries may view cathode plates as fixed asset or consumables depending on their operational characteristics. This paper examines the issue of cathode plate life and the strategies and philosophies used by different plants in the management of their cathode plate asset. Some plants operate with their original plates after more than 20 years. Others accept high turnover and regular maintenance as normal operating practice. Reference data are provided on plate life for various operating plants including benchmark plants achieving best-practice plate life and operating cost. The role of the electrode handling equipment on cathode plate longevity is also examined, including latest developments in Cathode Stripping Machine, robotic copper stripping, and full-automation production cranes. The ability to identify and manage the population of plates in service is also critical for maximising plate life and minimising its overall operating cost. This paper discusses a novel and unique RFID system for tracking and managing cathode plate inventory. INTRODUCTION Permanent cathode plates The adoption of permanent stainless steel cathode electrodes in the electro-refining of copper was the most significant process development since the first commercial electro-refineries were built in the late 19th century. It provided significant improvement over the labour intensive and complicated starter sheet system. Copper grows over the permanent cathode blade for a number of days before being stripped, and the permanent cathode can be returned straight back to cells for the next cathode cycle. Glencore Technology (formerly Mount Isa Mines (MIM), then Xstrata Technology) has been manufacturing permanent stainless steel cathode plates from the late 1970s with the birth of ISA PROCESS™, and the Kidd process that came one decade later. Invented and commercialised by Mount Isa Mines, the ISA PROCESS™ was first implemented into Copper Refineries Limited (CRL), Townsville, in 1978. The KIDD PROCESS by Falconbridge evolved in the 1980s and was first implemented into the Kidd Creek Tankhouse, both operations converting from traditional copper starter sheets.

Jan 1, 2019

By A. H. Lang

Introduction Tin continues to be as much a strategic metal as it was during the war. This situation is due to the fact that the tin mines in the major producing areas of Malaya and the Netherlands East Indies have not yet reached their pre-war production. Moreover, the world requirements for tin in certain fields, particularly in the food pack industries, are steadily increasing. At present, tin is still under International allocation by the Combined Tin Committee, of which Canada is a member nation. This Committee reviews periodically the availability of refined tin for export from the producing countries and makes allocations of tin to ensure equitable distribution to the consumer countries. In 1947, availability permitted an allocation of only 70 per cent of stated requirements. From 1935 to 1938 the price of tin in New York averaged 49 cents a pound and during the war the price in Canada was controlled under a subsidy programme at levels from 60 to 70 cents per pound. Just recently, this price has been raised to 96 cents. The value of the Canadian production amounts to about half a million dollars annually and the whole of this is obtained as a by-product of the lead-zinc-silver ores of the Sullivan mine in British Columbia. In 1947 Canada's imports of tin were 3,961 long tons valued at over $6,000,000. In addition, tin plate to a value of $8,000,000 was imported from the United States; the tin content of this is estimated to be from 650 to 700 long tons. An increase in domestic production would, therefore, be of great national importance, and the present high price may make the search for and development of tin deposits more attractive than it has been in the past. Although no one can foretell what future prices will be, there is reason to believe that, unless there is a drastic downward revision of production costs, the price will be maintained at present levels for some years. A number of tin occurrences are known in Canada, but none of these have been developed for their tin content alone.

Jan 1, 1948

A series of field and laboratory evaluations were conducted in order to characterize the effects of a Mann+Hummel SMF-AR® diesel particulate filter (DPF) system on the aerosols and criteria gases emitted by diesel engines. This system, with a durable sintered metal filter media and available active regeneration via an on-board electrical heater, has been considered for retrofitting diesel engines used in light- and medium-duty underground mining applications. Two DPF systems were installed on a forklift and locomotive from the underground mining fleet of the Vale?s Creighton Mine and evaluated over a 1,500-hour trial. This evaluation was complemented with field and laboratory emissions tests. The field tests were performed on the vehicles while at the Creighton Mine surface shop. During those tests, the emissions were assessed for the engines operated at hydraulic stall, high idle, and low idle conditions. The laboratory tests were executed at the diesel engine emissions laboratory at the National Institute for Occupational Safety and Health (NIOSH), here the DPF removed from the forklift was further evaluated at four steady-state engine operating conditions as well as at transient conditions using a custom-designed duty cycle. Very similar methodologies were used during field and laboratory tests to measure concentrations of aerosols and criteria gases in the diesel exhaust, both upstream and downstream of the DPF system. The concentrations and size distributions of aerosols were measured using a fast mobility particle sizer spectrometer, in exhaust diluted by a partial flow dilution system. The concentrations of CO2, CO, NO, and NO2 were measured in the raw exhaust using a Fourier transform infra-red spectrometer. Both field and laboratory emissions tests showed that the evaluated DPF systems were very effective in reducing aerosol emissions from all tested engines, and for all test conditions. The systems were found to have minor effects on gaseous emissions from those engines. The findings from this study should help the mining industry to better understand the benefits and challenges of using DPF systems to control the exposure of underground miners to diesel aerosols.

Aug 1, 2013

By David Forrester

"At the 95th CIM Annual General Meeting in Calgary, 1993, a paper entitled “Progress on Futuristic Mining Technologies” was presented(Matthews and Sarin), in which they outlined the goal of continuous excavation of hard rock and some of the technologies being developed to achieve it. The subject continues to be featured in periodic reviews and articles in the literature, (Gertsch, 1994; E&MJ, 1995). Matthews and Sarin note the considerable success of the development and application of continuous mining technologies in the soft rock under-ground mining industry, especially those in coal and potash, with major benefit to overall production, productivity and economic viability. It is the belief that similar achievements can be realised in the underground hard rock mining which continues to drive the development of hardrock continuous mining technology.This overview has been prepared specifically for this issue of the CIM Bulletin. It attempts to tie together current advancements in continuous mining in soft rock (where remote control and automation are already well established) with the background and status of development in hard rock continuous mining. Following a brief review of key factors and machine types, soft rock aspects are discussed, then a more detailed review is given of hard rock technology, with particular reference to Canada’s HRDK Mining Research Ltd. and their key role.The mining industry has long been at the forefront of technology development, for example, the application of the early steam engine to reach reserves at greater depth for dewatering mines in the industrial revolution. By necessity, the individual characteristics of seams and orebodies dictate the mining method, continually presenting mining engineers with new challenges. One of these is the extraction process itself and the goal of replacement of the drill-blast-muck cycle by continuous excavation. Very soft rocks have always been mineable using some form of cutting, even with primative tools. However, as the challenge has been taken up, technologies have evolved to steadily increase the hardness of rock that can be mechanically excavated. It may surprise some readers that at least three machines have successfully cut and loaded rock with an unconfined compressive strength (UCS) of 250 Mpa to 300 MPa (36 000 to 43 500 psi) in field trials (Table 1)."

Jan 1, 1996

By J. E. Moran

A groupd of French capitalists, La Compagnie Française des Mines d'Or du Canada, has undertaken the considerable task of developing Otter creek, in the Atlin district, B.C., by hydraulic mining methods. It has long been known that the gravels of this stream carry sufficiently high values in gold to make it attractive as a mining venture, but it was impossible to ignore the existence of formidable natural obstacles to hydraulicing them, and these needed to be taken into serious account before embarking upon any costly programme of development. The tide to the Otter Creek leases was originally held by Mr. H. Maluin, a French engineer well known throughout the north, to whom was to fall the task of financing whatever programme might be decided upon. It was he, too, who would have to assume the responsibility of finally passing judgment upon the practicability of the various devises for overcoming the adverse natural conditions. With an infinite attention to detail, which I believe to be a characteristic of the French people generally, he studied his problem and was finally able to submit to his financial backers a programme which left the very minimum possible to the hazard of accident or chance. Dr. Mandy, on his visit to Otter creek this season, expressed the opinion that our method of opening this difficult creek presented certain features which might be successfully applied in placer operations elsewhere in British Columbia, and it is largely for this reason that the present paper has been prepared. I shall set forth, as well as I can, the practices which have enabled us to overcome rather easily some of the obstacles which nature had unkindly placed in the path which we must take. The natural flow of water in Otter creek is far too little to deal success-fully with the rather excessive amount of glacial drift overburden which lies directly over the gold-bearing gravels. For this natural defect, the only remedy was to procure more water. This we have clone through a system of flumes and ditches, totalling between ten and eleven miles in length, which bring to the mine a supply of water adequate for our needs.

Jan 1, 1932

By China University of Mining & Technology, Yuemin Zhao, Bo Zhang, Liang Dong, Zhenfu Luo, Chenlong Duan

"In China, approximately 65% of coal reserves are in the west region, where water shortage is a serious problem: high-efficiency dry coal beneficiation technology is desired. Using magnetic powder and fine coal as heavy medium, and using air as the fluidizing agent, a novel air dense medium fluidized bed separator is proposed for coal preparation. Coal can be efficiently separated according to density in the fluidized bed, where bed density is steady. The separator is highly reliable, the circulation quantity of heavy medium is low, and the gas distributor cannot be easily easily. The world’s first industrial modularized dry coal preparation plant was built by China University of Mining and Technology. Dry coal beneficiation technology was first used to produce low-ash coal. Results of industrial production show that the ash content of clean coal is 3.46%, the probable error E value is 0.055 g/cm3, and the organic efficiency is over 90%. The advantages of the modularized dry coal beneficiation system are the high separation accuracy, the simple process flow, the low operation cost, low energy consumption, and so on. This technology provides a new effective method for coal separation in acid region and coal tending to sliming.INTRODUCTIONCoal is the most important primary energy source in China, where coal output reached 3.68 billion tons in 2013 and represents approximately 68% of the primary energy consumption. Coal has made a great contribution to the development of the Chinese national economy, but it also brings serious environmental pollution. However, approximately 65% of coal reserves are in the arid west region in China where water shortages present a challenge for wet coal preparation technology. In addition, the abundant lignite resource, because it is easy to mud in the water, should not be treated with the wet separation method. Therefore, it is critical to develop highly efficient dry coal preparation technology to meet the demand in arid areas. Further, water resource shortages are a global problem, thus the development of efficient dry coal preparation technology in has potential application in other water-short countries like South Africa, Brazil, India and Turkey."

Jan 1, 2016

"5.1. IntroductionThe sample preparation requirements for bulk analyses of platinum-group elements (PGE) are different from the requirements for ore microscopy and in-situ analyses. It is necessary that the initial sample collection results in as representative a sample as possible for both types of analyses. Ingamells (1980) believes, however, that sampling is always imperfect and that there is no such thing as a truly representative sample. Once collected, the usual low content and irregularly dispersed nature of the PGE require that samples for bulk analyses be made as uniform as possible, whereas in samples for ore microscopy and in-situ analyses the PGE must be concentrated. Because of the generally high specific gravity of platinum-group minerals (PGM), certain precautions must be taken, such as mixing the sample material in the bags prior to opening.5.2. Preparation forBulk Analytical MethodsThe principal factors that determine the size of the sample required for a bulk analysis are grade, heterogeneity and grainsize. Initially, the grade and sample heterogeneity can only be estimated and a sampling methodology is developed with experience. It is essential at all times, however, that the assayers have information about the source of the sample and the purpose for the analysis. Information on the grain-size, which can only be obtained through mineralogical analysis, is also very important for PGE analyses, but, unfortunately, is often ignored.5.2.1. Samples fromUnconsolidated DepositsConcentrations of PGE may occur in eluvial deposits as well as in a large variety of alluvial deposits, including those of fluvial and glaciofluvial origin. These deposits are often difficult to map and sampling is further complicated by the wide range, from sand-size to boulders, of the non-POE-bearing constituents, and by the irregular distribution and shape of the ""pay streaks"". PGE concentrations in unconsolidated deposits are largely composed of resistant Pt-Fe and Os-Ir-Ru alloys (cf. Cabri and Harris, 1975 and Raicevic and Cabri, 1976), thus making comminution to the usual-150 to -200 mesh somewhat unreliable, due to the malleability of these alloys."

Jan 1, 1979

By W. L. Stuewe

The Dominion Steel and Coal Corporation requires enormous quantities of bricks each year for its Sydney steel plant operations. Clay brick of all types are purchased, while silica brick is made in the Company's plant at Sydney. A description of this plant was given in a paper presented by H. B. Gillis and F. C. Morrison at the 1938 Annual General Meeting of the Institute. The rock used to make silica brick was for years obtained from a quarry at Leitches Creek, about eighteen miles from Sydney. Due to the gradual deterioration of this deposit, the Corporation was forced to look for other sources of supply. In 1945, the problem was presented to the Nova Scotia Department of Mines and, through the efforts of Dr. A. E. Cameron and Mr. J. P. Messervey, an examination was made of a silica-rock deposit some six miles northwest of Yarmouth, N.S. Preliminary samples proved satisfactory, and arrangements were made with the Department of Mines to ship to the steel plant at Sydney a fifty-ton car load for the purpose of further testing. Brick made from this sample shipment stood up very well in the furnaces. At the same time, two hundred and fifty tons of silica rock from a deposit at Lac Bouchette, Que., were purchased from the Industrial Silica Corporation, and brick made from this rock also was found suitable for our requirements. Comparative transportation costs, however, led to a decision to open the Yarmouth deposit. The silica rock, or quartzite, of this deposit outcrops at Chegoggin point along what is known as the 'Pembroke shore', a northerly trending section of the coast-line at the extreme southwest of the Province, in Yarmouth county. The country here is fairly flat, with elevation averaging about twenty feet above high tide, and is for the most part mantled by a growth of brush and some scrub trees, chiefly small fir. Bed-rock is generally concealed beneath three to four feet of clayey soil, but scattered outcrops of the quartzite indicated that a band of this rock, some 260 feet wide, extended inland in a northeasterly direction from Chegoggin point at least to Utleys lake, a distance of about three miles.

Jan 1, 1947

By K. Peake, A. Dalvi, V. Hernandez, S. Chang, M. Oliazadeh

"Ironstone Resources Ltd. is developing the Clear Hills oolitic iron ore deposit in northwest Alberta, Canada. Sources of oolitic iron ore worldwide are abundant and ubiquitous, but there is currently no commercial technology to extract iron from oolitic iron ores. Mineral processing of the ore to generate a commercial iron ore concentrate is very challenging due to the nature of these ores. Accordingly, Hatch and Ironstone are developing a new pyrometallurgical process (Hatch Ironstone Chloride Segregation) to produce metallic iron from high silica and high phosphorus oolitic iron ores. Following the chloride segregation process, the treated ore is subjected to fine grinding. The iron is then separated by magnetic separation. The iron grade and phosphorus content of the final product shows a strong dependence on the separation methodology and the grind size. The pyrometallurgical process has been developed and tested at a lab-scale pilot plant. The commercialization of this technology could provide an opportunity for the development of a new alternate iron making technology. This paper presents the results of test work done on the raw iron ore to create a concentrate and also on the products of the pyrometallurgical process for the production of a high grade 90% metallic iron product.INTRODUCTION Oolite is a sedimentary rock formed from ooids – spherical particles with concentric layers. There are a number of large oolitic iron deposits where the mineralogical form features a low iron content and high concentration of impurities making them presently impossible to exploit on either a technical or economic basis. The fifteen largest oolitic iron ore deposits in the world are estimated to contain approximately 337 billion tonnes of iron ore, which would be a significant source of supply for worldwide steel production. A viable process that can economically recover iron from these oolitic iron ore deposits could become an important new technology to meet future demand in the steel industry. Hatch and Ironstone have demonstrated that oolitic iron ores can be exploited to produce direct reduced iron (DRI). Direct reduction ironmaking is a method for producing solid metallic iron using different techniques compared to the blast furnace process, which is the more conventional ironmaking route. The demand for the construction of direct reduction ironmaking plants has increased in response to the increasing demand for crude steel. It is viewed as a method of providing low-residual iron sources to scrap-based steelmaking in electric arc furnaces."

Jan 1, 2014

By G. S. Dobby, J. A. Finch

"I. INTRODUCTIONA significant development in flotation over the past few years has been the increasing industrial use of flotation columns, primarily in Canada. The column differs dramatically from conventional mechanical flotation machines, both in design end operating philosophy, which has been a principal reason for its slow acceptance by the mineral industry. Boutin, Tremblay and Wheeler (1. 2) developed the concept in the early 1960's and since then plant and laboratory columns have been marketed commercially by Column Flotation Company of Canada Ltd. In 1980-81 at Mines Gaspe, Quebec, three columns replaced 13 conventional cleaners in a molybdenum upgrading circuit, with superior results (3). Since then many of the copper producers in British Columbia have installed columns for copper and molybdenum cleaning, including Gibraltar, Lornex, Highmont and Island Copper. There now appears to be widespread interest in flotation columns.The column is particularly attractive for applications involving multiple cleaning stages and can upgrade In a single stage compared with several stages of mechanical cells. This results in simpler, more controllable circuits. Importantly, the column itself is well suited to computer control. A significant problem, however, has been that of translating laboratory data to plant performance. The purposes of this communication are to address the problem of column scale-up and to describe some of the transport mechanisms of a flotation column, leading to a kinetics based model.A schematic of a flotation column is shown in Figure]. Industrial columns are up to 13 m high and 0.3 to 1.8 m in cross section (either square or circular). Three zones can be identified:a collection zone, with feed entering 2 to 3 m below the top of the column and descending against rising bubbles generated at a gas sparger; a washing zone, where a packed bubble bed is generated by a downward flow of wash water; and a conventional froth (2 - 5 cm thick), the sole purpose of which is particle transport to the launder. The tailings withdrawal at the bottom of the column is controlled at a rate slightly greater than the feed flowrate (called a positive bias).An important element is the washwater, added just below the froth zone. The component of the washwater that flows downward (to make up the bias) is sufficient to prevent coalescence of rising gas bubbles. The packed bubble beg so generated is very efficient at suppressing gangue entrainment to the concentrate."

Jan 1, 1985

By R. Grant, C. Bazin

"Brunswick Mining has investigated grinding media optimization for the purpose of improving the flotation feed and regrind product size distributions to enhance metal recoveries. This paper presents the findings of on-going testing of various sizes and shapes of grinding media. Plant observations combined with estimated breakage rates demonstrate the importance of appropriate selection of media sizes on the milling operation.IntroductionBrunswick Mining and Smelting is located near Bathurst, New Brunswick, and operates one of the world's largest lead and zinc mines. The ore mineralogy and processing flowsheet have been described elsewhere (Petruk and Schnarr, 1981; Shannon et 01., 1993). Despite the 25 years' milling experience, there has been considerable disagreement as to the required grind size (Grant et 01., 1991). Since 1964, fineness of the flotation feed ranged from 60% to 80% passing 400 mesh (37 um) and averaged slightly above 71% in 1992. Results from mineralogical analysis (Petruk and Schnarr, 1981), laboratory and pilot plant experiments, as well as plant sampling (Grant et al., 1991; Hendriks and Ounpuu, 1985; Shannon et al., 1993) indicate that improved metal recoveries can be achieved by an increase in the fineness of grind, and more specifically by maximizing the amount of material in the 15 urn to 25 um range.This paper shows the results obtained so far from the evaluation of the effect of grinding media size and shape on grinding mill efficiency. The problem of finding optimum grinding media size, shape and composition has been recogrtized since the early 19405. The main criterion for the selection of media size is the size of the material to be ground (Bond, 1958). Although several relationships have been proposed to assist in the selection of grinding media size, none of them are entirely satisfactory (Wills, 1988). Other approaches using the breakage rates and process simulators were developed to help in the selection of grinding media size (Austin et al., 1976; Lo and Herbst, 1986; Concha et 01., 1992; Samskog et al., 1990; Martinovic et al., 1990). Although considerable effort was put into the analysis of grinding media size, very little information is available on the effect of grinding media shape (Norman and Decker, 1985, p. 3C-4). Norris (1952), Kelsall et al. (1973) and Herbst and Lo (1989) have shown that balls are more efficient than other shapes of grinding media including truncated cones and cubes."

Jan 1, 1994

By I. Paredes, R. Díaz, H. Henao

Smelting of copper concentrate generates a significant amount of dusts which are collected in electrostatic precipitators. This material, which is a complex oxide of Cu, Fe, S, As, Sb, Bi and others, is difficult to recirculate into the smelting process due to the reported high concentration of arsenic. However, the dust also has concentration of copper above 10wt %, aside from reported contents of silver corresponding as much as 25wt% of the total inventories of this element in the smelters. Thus, it is of economic and environmental interest the development of a process able to reduce the concentration of arsenic in the dust and produce a material suitable to be recirculated into the smelting process. The present experimental work shows the results of a process of dust sulfidization-oxidition able to remove more than 65wt% of the arsenic present. INTRODUCTION Copper sulfide deposits worldwide exhibit increasing concentrations of arsenic. One case of interest would be the copper ores from the northern zone of Chile, which report high concentrations of enargite (Cu3AsS4) (Revista química, 2015) (Latinominería, 2014). The obtained concentrate from this ore is treated in a Fluidized Bed Roaster, producing calcines with low concentration of arsenic (<0.5 wt% As). This material is suitable to be treated in a Flash Furnace. At the roasting process, the arsenic is volatilized and then precipitated as fine particles of complex oxides. Most of this particulate material is removed from the gas stream through a device called Electrostatic Precipitator (Minería chilena, 2014). The experimental results reported in the literature indicate that arsenic present in these particulate materials (or dusts) cannot be eliminated in oxidizing atmospheres (air) or with inert gases (N2) in a Fluidized Bed Roaster even at temperatures as high as 700°C. There is also information that even the recovery of valuable metals from the dust is difficult through hydrometallurgical processes (private communication). This is how in some foundries these dusts are considered environmental liabilities. Regarding the decomposition of enargite (Cu3AsS4) in neutral atmosphere, it is reported in the literature (Padilla, 2001) that the main chemical reactions are:

Jan 1, 2019

By J. Bruce See

INTRODUCTION This symposium at Cu 2019 has been organised to honour and celebrate the career and achievements of Dr Phillip John Mackey, an internationally recognised expert in the production of non-ferrous metals, especially copper and nickel smelting and refining. Phillip was born in Epping, a suburb of Sydney, New South Wales, Australia on 19 April 1941 and is one of 4 children of Gilbert and Philomena (nee Bartlett) Mackey. After completing Primary School in Epping, he attended Marist Brothers High School in Eastwood, Sydney and graduated in 1957 as the Dux of the School. Phillip’s father, being on the staff of the Sydney Technical College, in Ultimo, Sydney had the opportunity in the early 1950s to meet the late Professor Sir Rupert Myers, Foundation Professor of the School of Metallurgy at the New South Wales University of Technology (later called the University of New South Wales or UNSW). Gilbert Mackey was impressed by the new young Professor of Metallurgy and encouraged his son to study metallurgy - at the time an expanding industry in post-war Australia. EDUCATION AT THE UNIVERSITY OF NEW SOUTH WALES Phillip commenced at UNSW in 1958, graduating with honours in 1963. His undergraduate education and training included a few years of part-time study while working at British Motor Corporation on sheet metal forming of car bodies. At University Phillip developed his talent for teamwork. He was a contributing writer to the University newspaper, Secretary of the UNSW Students’ Union and was active in the UNSW Metallurgical Society and co-editor in 1963 of “Metallurgical Review,” the annual journal of the UNSW Metallurgical Society. His diverse interests and curiosity about the world around him were likely nourished while at University. Upon completing his Bachelor’s degree, Phillip was awarded a Commonwealth of Australia Postgraduate Research Scholarship. He began his PhD in 1964 on the thesis topic “Studies in Heat Transfer between Dispersed Liquid Metals and Gaseous Atmospheres” working under the supervision of then Associate Professor Noel Warner, an outstanding Professor at the University. Professor Warner is now an Emeritus Professor at the University of Birmingham and is internationally respected for his pioneering theoretical and practical work on established and innovative smelting processes.

Jan 1, 2019

By T. H. North, A. G. Glover, R. J. Pick

"Girth welding operations represent the rate-limiting step in pipeline construction. A joint industry-university program was set up to establish the field welding characteristics of large-diameter, high-strength line pipe.Theoretical work carried out at the University of Waterloo showed that pipe wall thickness and joint misalignment prior to welding has a marked influence on the lifting stresses acting on the root pass of girth welds. Pipe diameter and pipe ovality had negligible effects. Super-position of lifting and residual stress (caused by the fusion welding operation) highlighted regions of the weld bead most susceptible to hydrogen-induced cracking.The field welding characteristics of 1219-mm-diameter, 13.72-mm-wt Grade 483 line pipe were evaluated using a specially designed test rig. The principal test variables were lift height, delay time after root pass deposition, preheat temperature, pipe composition and joint misalignment prior to welding. For any given life, preheat and joint misalignment prior to welding had the most significant effect on cracking tendency.The output of this program has industrial significance and illustrates the beneficial features of university-industry collaboration.IntroductionField welding operations comprise the rate-limiting step during pipeline construction. Crack-free girth welds must be made in a wide range of weather conditions and consequently the field weldability of line pipe compositions directly affects pipeline integrity and construction economics.Pipe-laying practice comprises root bead deposition followed by a skidding operation involving lifting (or lowering) the pipe length onto skid s so that the next pipe length can be aligned prior to welding. Consider pipeline construction using 24.4-m lengths of 1219-mm-diameter , 13.72-mm-wt Grade 483 pipe weighing approximately 10,000 kg. Skidding involves loading a 3-mm-thick root bead by moving the free end of the pipe through vertical distances of up to 700 mm . The likelihood of cracking in these circumstances depends on the inherent crack susceptibility of the pipe composition employed, on the hydrogen content of the deposited weld metal and on how well the joint handles the external stressing caused byskidding."

Jan 1, 1981

By R. M. Giegerich

"This paper begins with a brief history of Madawaska Mines, a brief description of the geology, mining methods and equipment, and the historical development of 7/8-in. tapered drilling equipment. It then outlines the performance characteristics and inherent problems of the traditional 12-degree, tapered connection, blade-type insert bits. Service-free (Unipass) button-type insert bits are presented as a possible solution to these problems. The paper concludes with an analysis of button bit performance to date.Brief History of Madawaska MinesMadawaska Mines Limited, near Bancroft, Ontario, is in Faraday Township, Hastings County, approximately 100 miles northeast of Toronto and 100 miles west of Ottawa.The mine re-opened in 1976committed to 1,500 tons per day to provide approximately 600,000 pounds of yellowcake (U3O8) per year to A.G.I.P. (an Italian government agency) under the joint ownership of Federal Resources Corporation, Salt Lake City (51%), and Consolidated Canadian Faraday Limited (49%). At present, the mine is producing approximately 2 pounds per ton (.1% U3O8) at the rate of 60,000 pounds per month. The mine employs about 400 employees.Brief Description of Geology, Mining Methods and EquipmentGeologyThe Grenville metasediments of the mine area are chiefly paragneiss, amphobolite and some carbonate (marble) rocks, which were intruded by a basic rock, altered to a metagabbrometadiorite. These formations are generally concordant, striking east to northeast and dipping 45 to 60 degrees to the south. Locally, the metagabbro is often discordant. The above group of rocks (mixed hybrid gneisses) forms the hanging wall of the south-dipping Faraday granite sheet and was intruded by nepheline syenite, syenite and granite. The ore occurs in the granite-syenite-pegmatite dykes that are probably genetically related to the Faraday granite. The ore shoots are erratically distributed within the pegmatite bodies, mainly on the hanging or footwalls but also medially. Their size varies from 50 to 350 feet in length, 5 to 40 feet in width and 50 to 200 feet in height. The ore occurs most frequently in a medium-grained granite or syenite, well hematized with 10 to 30% mafic crystals of pyroxene, amphibole and/or relics of the host rock."

Jan 1, 1982

By M. Fiset, D. Belley

"In a country with a cold climate like Canada, the cost of replacing worn parts of snowplow equipment such as blades, is enormous. A great number of these blades, with different mechanical properties, are available, but few studies have been made to facilitate their selection according to the optimum ratio of wear resistance to cost. To attain this objective, laboratory tests have been developed to correlate test results with those obtained from various road service conditions. The test materials, 1080steel in different states, 1090steel and D2 tool steel were chosen to cover a large range of hardness as well as different microstructures. Comparison of the wear resistance of the test materials relative to a standard revealed, in general, a good correlation between the results of laboratory cement wheel tests and those from the road tests. Scanning electron microscope wear scars of laboratory and road test specimens were compared to determine if similar removal material mechanisms were active. IntroductionThe correlation between wear tests in service and those performed with the aid of laboratory equipment is of considerable interest. As a matter of fact, when correlation exists, it allows one to evaluate the performance of a material more easily and at a lesser cost.Several authors have been interested in simulating various wear circumstances, especially abrasive wear. In particular, the simulation of wear on implements working the soil, has been tried by several researchers. The test using the rubber wheel seems to be the one giving the best correlation if the soil is rather sandy and its moisture content is low.However, little work has been done concerning wear on the plates, skids and blades attached to trucks used for levelling and snowplowing; such equipment being used to keep roads clear in northern countries. Now each year, companies introduce new steels by claiming that the y are superior in performance to their predecessor s and invariably they demand a higher cost. The study presented here was undertaken with the goal of making a more judicious choice of these steels by simulating their behaviour in the laboratory. Moreover, the examination of abraded surfaces in situ and in the laboratory have also allowed us to compare the respective wear mechanisms."

Jan 1, 1988

By J. A. Meech, C. A. Harris

"The application of control theory in mineral processing is more difficult than in other industries because of the complex nature of the unit processes involved and because of problems with accurate on stream measurement of process variables. Conventional control is based on proportional, integral and derivative functions of a continuously measured error term. Computer control can enhance these actions by incorporating logical routines to switch from one relationship to another. The success of this logical approach depends on our understanding of the process dynamics and the stability of the process and model under all conditions. Typically the model does not apply at all times in mineral processing because of frequent and unmeasurable changes in the ore parameters.Recent advances in the theory of fuzzy sets have led to the application of this science to process control. Fuzzy Logic can be used to develop heuristic or rule-of-thumb controllers with the strategy based on the actual operating practice of experienced plant operators. Control action has increased flexibility through the adaptation of human reasoning. Acceptance of the control system by operating personnel is significantly higher because of their participation in its formulation. The requirement of an exact model is not essential.A heuristic controller has been designed and tested with a computer simulation model of a secondary crushing plant. The results of this study are discussed and future applications of this control technique to other mineral processes are suggested. IntroductionThe application of control theory in mineral processing is more difficult than in other industries because of the complex nature of the unit processes involved. Mineral processes typically are characterized by non-linear relationships between input and output variables. Many of these variables cannot be monitored accurately on-stream and so long time lags on the measurement loop are features of the system. The processes, themselves, often have long time-varying responses while the process loads fluctuate significantly on a short-term basis.Attempts to control these processes have led to the formulation of mathematical models to describe each unit activity. Adaptive techniques have also been tried to compensate and account for process changes and vageries. These approaches are mathematically rigorous so that their complexity and precision limit their usefulness when applied to ""vague"" processes."

Jan 1, 1987

By L. A. Mells

"A laboratory test program was initiated by the Department of Energy, Mines and Resources as part of the National Uranium Tailings Program to investigate the applicability of a radium selective ion exchange complexer for removing radium from Canadian uranium mining effluents. The test program was carried out by Melis Consulting Engineers Ltd. under contract to the Department of Supply and Services using the Saskatchewan Research Council facilities located in Saskatoon, Saskatchewan.The results of this work showed the ion exchange complexer, Dowex XFS 43230.00, to be efficient in removing radium from contaminated water of uranium mining operations with the ultimate loading capacity of the resin on one type of water treated being determined as approximately 1,600 Bq/cm3 of new resin. Although this resin has potential application for treatment of effluent streams in uranium operations it has been identified that the resin efficiency and capacity is directly related to the chemistry of the water being treated and site-specific testwork is required in order to establish reliable design data for full-scale operations.IntroductionThe possible applicability of a radium-selective ion exchange complexer for removing radium from Canadian uranium mining effluents had been identified and discussed as a possible alternative to present radium removal methods during a review of disposal technology options for the National Uranium Tailings Program of the Department of Energy, Mines and Resources(1). Work by other workers(2.3) had shown the complexer to be very efficient in removing radium from contaminated water. Also, plant trials on contaminated minewater at the Mt. Taylor uranium mine in New Mexico is reported to have shown the resin complexer to be efficient under plant operating conditions.As a result, a laboratory test program was initiated by the Department of Energy, Mines and Resources as part of the National Uranium Tailings Program to investigate the suitability of this resin for Canadian uranium mining effluents. The test program was carried out by Melis Consulting Engineers Ltd. (MCEL) under contract to the Department of Supply and Services using the Saskatchewan Research Council (SRC) facilities located in Saskatoon, Saskatchewan."

Jan 1, 1985