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By J. B. Mitchell

Using digital image correlation the evolution of strain and strain at the onset of localisation resulting in a hot tear has been determined for alloys AA6111 and Al¬0.5wt% Cu during solidification. High resolution images of hot tear formation and growth were captured during a constrained bar test that incorporated a glass window above a central hot spot region. The images were analysed using digital image correlation software to measure the evolution of displacement and strain based on tracking the motion of discrete features on the as-cast surface of the sample. Temperature data was also acquired with a thermocouple cast into the sample in close proximity to the hot tear. The interval starting from the point immediately after solidification shrinkage ends (the metal pulls away from the glass) and finishing when the first sign of a crack or hot tear is visible to the eye was used to determine strain data. The minimum strain at which strain localisation occurs was found to be 0.0069 in AA6111 and 0.0021 for A1-0.5%Cu.

Jan 1, 2007

By E. J. Burrough

Coal Reserves The Crowsnest Pass coal fields form part of a greater area which comprises the Inner Foothills belt of the Alberta coal fields and the southeastern coal fields of British Columbia. The most valuable and most extensive reserves of the bituminous coals of Canada are concentrated in this?area, of which the Crowsnest Pass fields form an important part. The extent of these coal reserves together with those of the rest of Canada were recently studied by the Geological Survey of Canada for the Royal Commission on Coal of 1946 (1). Quotin from the report, it is of interest to note that, prior to this work, the most widely known, and in fact the only Canadian-wide estimates of, coal reserves of Canada available to the Commission were those prepared by Dr. Dowling in 1913 (2). At that time it was estimated that Canada's reserves of coal were over twelve hundred billion tons. The more recent estimates of mineable coal for the whole of Canada are of the order of 10 per cent of that figure and are reported. as 99 billion tons, which is further reduced to 40 billion tons on the basis of the estimation of recoverable coal. This considerable divergence in estimated reserves is explained in part by the big difference in the bases of measurements. For example, in the original report, seams of one foot occurring at a depth of 4,000 feet were included in the estimates.

Jan 1, 1951

By Maciej Wrobel, Joerg Hammerschmidt, Dana Nurgaliyeva, Alexandros Charitos, Jochen Guentner

"Smelting of copper concentrates in the flash smelter generates a flue dust stream that contains a substantial amount of copper and accumulates more than half of the arsenic input to the smelter. In view of its high copper content flue dust recirculation to the flash smelter is common practice. Globally traded copper concentrates are affected by ever increasing arsenic contents and cause an increasing circulating arsenic load in flash smelter operation. Control of the arsenic level in the smelter slag becomes a challenge. This interaction of arsenic loaded copper feedstock, need for flue dust recirculation and slag quality control call for possibilities to reduce the arsenic load of the recirculated flue dust stream.The technology of partial roasting is known from pre-treatment of copper concentrates before smelting, and gold concentrates before cyanide leaching, to remove the harmful element arsenic. The partial roasting technology can be adapted for use in the purification of the flue dust. A major challenge for flue dust treatment is its extremely fine particle size compared to usual concentrates. For this reason Outotec developed a new process, which allows handling of such fine flue dust. This process solution provides an efficient possibility to reduce the arsenic burden in copper smelter operations.The suggested process aims at reducing the arsenic load to the smelter by treating the flue dust prior to recirculation to the smelter. The presented results are based on test work in the Outotec R&D-centre in Frankfurt. It is possible to remove 80-85% of the contained arsenic and to collect it in an arsenic trioxide residue with a concentration above 90%. The final off gas contains SO2 from decomposition of sulphates that are contained in the flue dust. The off gas stream is relatively small. We assume that it is possible to combine the off gas stream with other smelter process gas streams and to treat it in an existing sulphuric acid plant. Coal is used as fuel and as reductant to reduce pentavalent arsenate to trivalent arsenite. Arsenite can be kept in gas form at temperatures above 450°C. This permits separation of a calcine stream with arsenic levels of 0.2 – 0.3%, which is recirculated to the furnace.Outotec has a wide range of roasting testing facilities from lab-scale to pilot-scale. Outotec has both capability to modify and adapt technology to specific ore or concentrate requirements, but also the necessary infrastructure in its research centers in Frankfurt and Pori to do appropriate validation tests in lab and pilot scale size plants."

Jan 1, 2016

About Barrick Paste Backfill at Barrick Goldstrike Rodeo Paste Plant Cyclone Lab Testing Challenges and Lessons Learned Future Barrick Projects

May 1, 2013

By J. C. White

This paper, after a brief introduction giving the history and geology of the area, deals with mining operations at the Copper Mountain mine of Gaspe Copper Mines, Limited. It discusses development operations, and then goes into the mining methods employed, covering drilling, grade control, blasting practice, loading and hauling, and the road and service machines used.

Jan 1, 1969

By A. G. Roach

HISTORY AND LOCATION SEAL HARBOR GOLD MINES, LIMITED, was incorporated in January, 1934, to take over 116 acres of mining lands in the Stormont gold district, Guysboro county, Nova Scotia. The nearby ten-stamp Mulgrave mill was also purchased, and since that time 974 acres of adjoining properties have been secured from the Government by direct lease. The property is served by a motor road and is about two miles from the village of Goldboro, situated on the shore of Isaac's harbour. The bulk of ?the supplies are brought in by coastal steamer from Halifax, a distance of about 100 miles, since the nearest railway connections are at Antigonish, some 40 miles distant. EARLYY WORK The Seal Harbor properties include the old Partington and Beaver Hat mines. A small tonnage of ore was mined from each and treated on the properties in stamp mills, which were later torn. down . A survey of old records shows that this ore averaged about $8.00 gold per ton. Development work by the present Company was confined to the 100-foot level until February, 1935, but after that rime the incline shaft was deepened to 425 feet and the 300-foot level was explored east and west of the shaft. Six belts of ore were intersected to the west of the shaft. The ore from these belts was hand sorted and the ore portion was put through the 10-stamp Mulgrave mill to defray operating expenses and to serve as a sample of the deposits. The average recovery per ton from this sorted ore was $6.10. Samples of the ore were sent to the testing laboratories of the Mines Branch, at Ottawa, and of Canadian Industries, Limited, at Toronto. Recommendations from both of these authorities were for removal of the coarse gold by concentration and barrel amalgamation, followed by cyanidation of the residue.

Jan 1, 1937

By M. Jorgensen, I. Markland, D. Shuck

"The McLaughlin Mine owned by Homestake Mining Company is located 70 miles northeast of San Francisco in California's coastal range. The mine began operations in February of 1985. The mill currently processes 3,000 short-ton per day of sulfide ore that has an average grade of 0.15 ounces of gold per ton, plus another 3,000 tons per day in a newly completed oxide circuit. Annual production from the mine totals over 200,000 ounces.The sulfide ore extraction process involves three basic steps, grinding, oxidation of sulfide minerals in an autoclave, and cyanide leaching for recovery of gold in a carbon-in-pulp circuit. This process, which incorporates a new technology where oxidation of sulfide minerals is conducted prior to cyanide leaching to facilitate gold recovery, was successful from start-up. However, limitation in the grinding mills initially limited sulfide tonnage throughput.This paper discusses modifications made in the grinding circuit, both mechanical and operational, to resolve it deficiency. The SAG mill, in particular, was unable to achieve design tonnage initially and proved to be most troublesome. Complications occurred due to the hardness and variability of ore being processed, short component life, and a lifter /liner arrangement that had to be tailored to the particular circumstances at McLaughlin. IntroductionHomestake Mining Company's McLaughlin Mill, located in northern California, was designed to process a refractory gold ore at a rate of 3,000 tpd to render the ore amenable to cyanidation. Seven years transpired between discovery of the near-surface ore body in 1978 and the February, 1985 plant start-up. Development of the McLaughlin mill and open pit gold mine hinged on the use of autoclave technology to achieve design recoveries."

Jan 1, 1991

By G. Wilson

"Satisfactory hydraulic performance of a centrifugal slurry pump is not the only design criterion. If abrasive wear exists the severity of any damage can be reduced and the life of the wearing parts prolonged by selecting the correct pump to suit the conditions of service. This paper is concerned with the design and construction of centrifugal pumps for handling abrasive solids. The wear phenomena due to the slurry being pumped and the materials used to combat abrasive, wear are outlined. The hydraulic design of the impeller and casing and their relationship to wear and the hydraulic radial and axial unbalance are discussed. The prediction of abrasive wear in pumps can not be precise, as many factors are involved - and this is the object of current research."

Jan 1, 1973

By M. Massinaei, M. R. Yarahmadi, S. Zeidabadi, M. Oliazadeh

"Although the majority of new flotation column installations continue to be for cleaning or recleaning, an increasing number of flotation projects are specifying columns for roughing or scavenging duties. NICICO has recently installed flotation columns operating in rougher, cleaner and re-cleaner circuits at three new copper concentrators; Miduk, Sungun and Sarcheshmeh. Miduk is probably one of the unique operations that use flotation columns in a rougher circuit. The Miduk rougher circuit comprises five CISA parallel columns. The rougher concentrate constitutes 88% of final concentrate and reports to concentrate thickener. The rougher tailings are scavenged with ten 50 m3 mechanical cells. The scavenger concentrate is then reground and cleaned in three 3.2 m columns in parallel. The cleaner tailings are scavenged in six 50 m37mechanical cells. The cleaner tailings along with the rougher scavenger constitute final tailings.In Sarcheshmeh, the cleaner concentrate is re-cleaned in a column. The column tailings are sent back to the cleaning circuit and the concentrate is reported to the concentrate thickener.This paper reviews performance details of the flotation columns utilized in rougher circuits at Miduk and compares their metallurgical performances in an industrial scale with columns at cleaning circuits for copper flotation. Practical limitations for applying the flotation columns in rougher circuits will be discussed in details.INTRODUCTIONThe use of flotation columns has grown rapidly since the first successful commercial application at Mines Gaspe, where columns were used in a cleaning circuit to float molybdenite. Early applications of columns were restricted to replacing or adding final cleaning stages in existing circuits. Columns can achieve superior cleaning as compared to conventional cells due to their ability to support a large froth depth and the use of water for washing froth. Wash water travels down through the froth and crosses the pulp/froth interface, replaces the entrained particles reporting to the froth from pulp and improve the concentrate grade."

Jan 1, 2011

The Anglo Platinum Mogalakwena North concentrator was one of the first three hard rock mineral processing applications to utilise a HPGR circuit in preference to a SAG milling circuit. This was driven by the extreme competence of the ore that had given rise to throughput issues on the original South Plant. Despite more than adequate capacity and performance of the individual comminution units, the circuit has struggled to obtain full design capacity. A thorough review of the integrated performance of the circuit revealed a wide range of bottlenecks and underutilised parts of the circuit arising from design issues. Interestingly, the major opportunities lie in materials handling issues and mismatch of loads about the circuit. This paper presents the high-level outcomes and the associated opportunities, and is pertinent to all HPGR circuit designs.

Jan 1, 2012

By Brock Morrison, Bernt Ling

"The Kiruna Electric System is an all electric ramp haulage system developed for underground mining. This electric truck haulage system is currently operating on three continents. This paper will review the technology of the system, existing installations as well as the economical benefits to the mining industry. The system was designed and developed to extend and exploit the economical advantages of ramp haulage. Performance information is provided. IntroductionThe Kiruna Electric System has been the subject of a number of technical papers over the past sever al years. During that period, the content of the presentations has changed from concept and theory to prototype testing to description of installed and operating systems.The intent of this paper is threefold:1. to present a brief review of the technical features of the Kiruna Electric Systems;2. to review the existing installations with performance data; and3. to provide a description of on-going developments within the Kiruna Electric Program during 1991.The Kiruna Electric is a high capacity ramp haulage system for underground mining operations due to an All-Electric Drive System, including two heavy duty electric traction motors. The high capacity of the K1050E results from three factors:• payload - 50 tonne• speed - 18 km/hr to 20 km/hr up a IS0J0 ramp (total resistance)• availability - over 90010 during a 12-month period"

Jan 1, 1991

By R. B. Nourse, S. F. Gwynn-Jones, S. Nikolic, M. L. Bakker, I. McDougall, H. Joubert

"Tenova Pyromet’s core furnace knowhow and expertise has been built within the ferroalloy and nickel/platinum group metal (PGM) industries with the supply of electric furnaces for a number of nickel/PGM operators, including Eastplats, Lonmin, and Anglo-Platinum in South Africa, Mineraçào Serra Da Fortaleza in Brazil, and Norilsk Nickel in Russia. Tenova Pyromet has also supplied the electrode columns and associated electrode equipment – the heart of the electric furnace technology – for cobalt recovery in furnaces in Zambia and the Democratic Republic of the Congo. The quantity and size of projects undertaken by Tenova Pyromet has provided the opportunity to continuously improve furnace designs and the scope of supply, culminating in the most recent nickel/PGM project currently under construction at Northam Platinum. Through this innovative culture, the Tenova Pyromet Base Metals Initiative was formed in 2015 to develop the Novasmelt™ Furnace; a next generation optimised Top Submerged Lance (TSL) furnace design. The combination of Tenova Pyromet’s advanced Novasmelt™ product with our industry leading electric furnace technology are discussed with reference to applications for nickel and cobalt production. Flowsheet arrangements are compared summarising potential capital savings, operating requirements and achievement of downstream product quality.INTRODUCTION Tenova Pyromet is a leading player in the field of smelting technology development and equipment supply. Tenova Pyromet is the result of the union of three furnace suppliers under the Tenova banner: Techint Technologies (Tagliaferri), Core Furnace Systems Corp (Lectromelt) and Pyromet Technologies. The furnace experience of the combined groups dates back over a century with the earliest Lectromelt going into production in the early 1900s. Throughout the modern era, Tenova Pyromet has developed a reputation for providing dependable innovative smelting technology, high quality equipment and sound project execution to a worldwide client base with customer plants operating in Europe, Southern Africa, North America, South America, Russia, Kazakhstan, the Middle East, South Korea, and India. Tenova Pyromet’s core knowledge and expertise was developed in the South African ferroalloy, base metals, and platinum group metals (PGM) smelting industries. Tenova Pyromet has spent considerable effort on development and has contributed significantly to improve the state of the smelting industry. Tenova Pyromet’s electrode columns have become widely renowned and are now providing significant benefits, especially in increased furnace availability, to many smelting furnace operators. The electrode column is the heart of the furnace as it delivers a controlled amount of electrical energy, at an optimum depth in the burden/bath, to the smelting process. Every furnace is custom designed to the specific operating range and optimal operating point of that furnace and process"

Jan 1, 2017

By W. A. Toohey

Introduction From the earliest times it has been an inherent trait of man to build or create something for his own use or convenience. The need of some form of shelter other than that of the caves led him to bind together stones and other materials to form walls for his abode. Moistened clay which hardened upon drying was no doubt first employed. The Assyrians and Babylonians appear to have employed it or the bitumen found in their country. The early Egyptians and Greeks used some form of lime in their construction work. In addition to these shelters, other structures received attention, and, long before the Roman Empire was established, the Carthaginians made use of a natural cement as binding material. Portions of an aqueduct, seventy miles long, in Northern Africa, built in those early days, are still in use. The Etruscans were the first people in Italy to employ a mortar in their buildings. The Romans, learning the art from the Etruscans, improved the mortar by using a mixture of lime and volcanic ash, called 'puzzolan', and built not only roads but those famous structures, the ruins of many of which exist to this day. The Pantheon at Rome, built by Hadrian about 120 A.D., is perhaps the finest example of the early use of cement in building construction. With the decline of the Roman Empire, the art of making cement seems to have been lost, and for centuries the builders of Europe used only lime mortar. Pure limestones were selected for making the lime and great care was taken in the preparation of the mortar, the supply for one year being made the previous season and left to thoroughly slake or 'ripen' in pits covered with earth. The mortar thus produced gave excellent service above ground or where it was exposed to the hardening action of the air, but would not harden under water.

Jan 1, 1927

By W. Basuki, B. Setyotomo, L. Hakim, R. Hendrajaya

Due to high crack sensitivity of slab product of gas and oil line pipe application, its steel making process and alloy composition were evaluated and then improved to overcome its critical solidification process and reduced surface defects. The study was conducted at Slab Steel Plant Krakatau Steel. The purpose was to improve slab surface quality by reducing surface defects so that the slab surface doesn't need to be totally repaired. The method applied was by performing plant trial process, which the secondary process parameters such as alloying method and the casting parameters such as casting powder selection, metallurgical cooling, mould level control, and superheat were continuously monitored and then adjusted to the surface quality of the product. Based on the calculation of Ferrite potential of the steel, the chemical composition was designed to achieve optimum casting parameters in order to avoid high shrinkage during solidification. The results of the study are decreased surface defect quantity, and smooth casting process. The quantity of crack decreased by almost 90%. The slab surface repairing was significantly reduced from 85. % to less than 10%. These new casting parameters and developed alloy composition are then used and standardized for the mass production of the steel.

Jan 1, 2005

By M. Buarzaiga

High-pressure acid leaching (HPAL) of nickel laterite ores typically extracts 95% of the nickel and 91% of the cobalt. Impurity elements in the feed, such as iron, aluminium and chromium, also dissolve and can be detrimental to downstream processes. Rejection of impurities within the autoclave is highly desirable. Aluminium and iron hydrolyze, and then precipitate in the autoclave leaving only small amounts that are subsequently removed by precipitation in a neutralization step. The concentration of dissolved chromium can range from 200 to 2000 ppm, depending on the feed composition. Chromium in the liquid phase, usually in the hexavalent state, introduces many problems and can limit refining options. For example, chromium poisons the organics in solvent extraction making SX an expensive option. Also, hexavalent chromium must be converted to the trivalent state before it can be precipitated along with iron and aluminium. Bench-scale work confirmed that mixing small amounts of carbon-base additives, such as coke, with the autoclave feed significantly reduced chromium concentration in the autoclave discharge without any detrimental effects on paymetals recoveries and selectivity.

Jan 1, 2004

By W. D. Breil, C. B. Ison

A collection of general performance data relating to the G.H.H. - Gutehoffnungshiitte multi-rope friction hoist will be discussed together with some aspects of the following: overspeed supervision by a pantam device as opposed to the lilly type of fly ball control, automatic control systems, multi-disc braking, generator and motor winding, constant temperature monitoring, the development of an automatic hoist-rope lubrication system, and the control of rope tensions by the installation of G.H.H. - Gutehoffnungshiitte hoist rope fine tensioning units.

Jan 1, 1972

By M. Fall

The progressive depletion of ore available at shallow depths in several underground mines around the world means that underground mining operations would increasingly be carried out at greater depths and therefore at higher temperatures. However, our understanding of the effect of hot temperatures on the response (mechanical, economical, environmental) of cemented paste backfill (CPB) is still limited. Hence, an extensive laboratory investigation was conducted to study the performance of young and aged CPB, in response to deep mine temperatures. Several CPB samples with different compositions, cured at different temperatures (20 to 50°C) and different times (7 to 160 days) were tested regarding their mechanical properties, economical performance (binder consumption) and microstructural properties. The results show that hot temperatures significantly affect the performance properties of CPB at young and advanced ages. An increase in the curing temperature leads to a considerable improvement of the rate of gain of CPB strength and also to a significant increase of the strength of CPBs studied. CBP samples cured at hot temperatures show lower binder consumption and finer pore structure. Results of this study could serve as background information for the development of optimal mine backfill design procedures.

May 1, 2007

By J. L. Bowlby

Introduction In the following discussion, boiler-feed and mine waters will be considered from the point of view of the problems arising from the chemical nature of the mineral and gaseous impurities they contain. The theories underlying some of these problems will be reviewed for the purpose of getting a clearer concept of the problems themselves. Certain terms of a chemical nature, necessary to the discussion, will be explained on the assumption that they are not generally familiar to mining engineers. Finally, an attempt will be made to correlate theory and practice, with the abject of establishing certain limits to factors relevant to the problems, and to show that these limits are justified by practical experience. The general problems occasioned by the presence of mineral and gaseous impurities in boiler-feed and mine waters are: (1) Scale formation and corrosion in boiler systems. (2) Corrosion of mine pumps and pump fittings. These will be discussed separately. Boiler Scale Typical analyses of waters available for use in steam power-plants are given in the accompanying Table (Table I). All analytical data are expressed in grains per Imperial gallon. The bicarbonates of calcium and magnesium in the raw waters are shown as normal carbonates in the Table. Substances in the first five rows constitute the encrusting solids. All the waters listed in Table I would be classified as 'very good' in the schedule of classification for boiler waters adopted by the American Association of Railway Chemists in 1887. In spite of this classification, however, the waters contain sufficient encrusting solids to cause serious scale trouble after prolonged evaporation.

Jan 1, 1934

By W. M. Williams

"Although manganese is a metal virtually unknown to the layman, it is hardly necessary to point out to the engineer the importance of manganese in modern metallurgy, an importance intimately linked with iron (and steel), the basic materials of engineering construction for hundreds of years and certain to remain so for long into the future. World steel production will approach and perhaps reach 1 billion tons/year in the 1980s; with a manganese content between 0.5% and 1 % in ordinary steels, and more in specialty steels, manganese use worldwide will soon approach 15 million tons annually. Manganese was discovered and isolated in Sweden in 1774 by Karl Wilhelm Scheele (who also discovered molybdenum), but the element was only of scientific interest for several decades. By the early part of the nineteenth century, however, manganese oxide had become commercially available and was in use for colouring glass and for the production of chlorine. Commercial application in metallurgy appears to have been limited to the manufacture of crucible (or ""cast"") steel, a highquality product made by carburizing wrought iron, and melting it in small batches to make ingots which could be rolled and used for special applications, e.g. for the manufacture of fine tools or for ""steeling"" the cutting edges of implements such as wrought iron axes and chisels.* However, it was not until Bessemer's epoch-making invention of cheap steel in 1856, and the dramatic expansion of the steel industry thereafter, that manganese assumed the importance that it holds in modern steelmaking."

Jan 1, 1999

By The Staff

THE gold mining industry in Canada is today the most important stabilizing influence in the country. This factor was brought out particularly during the 'depression' years, when steady employment was given to men in that industry and the monies spent in supplies and power in turn benefited the country to a great extent. At the same time, a commodity was produced which was saleable in any market of the world, thus maintaining Canada's credit in foreign markets and keeping her trade balances equalized. We have a vast area known as the Precambrian Shield. The agricultural possibilities of this area are practically negligible and it will depend entirely upon the mineral and forest resources to make this district an economic factor in the life of Canada. To date, from the mineral point of view, we have been highly successful. There are, however, still vast areas to be explored. It is tedious and laborious work, entailing great individual hard-ships and the expenditure of much energy and money. During my thirty years' experience in the search for, and operating of, gold mines, I have come to the conclusion that although individuals may give all their time, energy, and money, Governmental assistance is absolutely necessary in the development of hydro-electric power sites and roads. The Governments, to date, have given splendid co-operation along these lines, but in order that this great industry may go ahead they should continue their good work and, if possible, give greater relief from taxation to mines situated at a considerable distance from the railway.

Jan 1, 1938