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By R. C. Bryce

"Accident prevention has been an on-going priorty for five years. In 1987, adherence to the ILCI five-star rating loss control program was started, and a first star was awarded. Extensive training programs have been undertaken to establish standard procedures and upgrade employee skills. Due to its location, Selbaie owns and rents housing in the town of Joutel and contracts a busing service to and from the mine. Employees from other areas are lodged in dormitories and fed in the site dining room. Accounting and warehousing services are carried out in efficient fashion. Employee relations are structured to provide prompt resolution of complaints and differences. No lost time due to industrial relations differences has been encountered during the history of the mine.Safety and Loss ControlAll mines are concerned and occupied with a wide range of activities to ensure the safety of its employees. Selbaie is no exception. Programs to achieve success in safety and loss control have been implanted since the start of construction and development at Selbaie and have followed three interesting stages of evolution."

Jan 1, 1990

By Xuanxue Mo, Zengqian Hou

"Abstract -Yidun Island Arc in Sanjiang Region is one of the important Kuroko-type volcano­ genic massive sulfide deposits (VMS) districts in southwestern China. Tectonically, the region is situated in the eastern portion of the Tethys orogenic belt, and is a late Triassic extensional island-arc. The island-arc underwent earlier arc construction, intra-arc rifting, later arc construction and back­ arc spreading during its evolution and formed a complete trench-arc-basin system, i.e., the Ganzi­ Litang suture zone, forearc basin, outer arc, intra-arc rifting zone, inner arc and back-arc basin from east to west across the island-arc.Kuroko-type VMS deposits and occurrences discovered so far are limited to within the intra-arc rifting zone of the Yidun Island Arc and tend to occur in groups or clusters distributed in separate fault­ bound basins; e.g., Zengke, Gacun and Xiangcheng basins, in which submarine volcanic rocks, especially bimodal volcanic suites, were extensively developed. The VMS deposits formed in the waning stages of volcanic eruption in the late Triassic and are hosted in the uppermost section of acidic volcanic rocks (rhyolitic-dacitic) within a bimodal suite. The orebodies are associated with these host rocks: rhyolitic-dacitic pyroclastic rocks and exhalites and chemical sedimentary rocks.Ali VMS deposits in Sanjiang are of the Zn-Pb-Cu type. The architecture of the deposits is two­fold, consisting of concordant lenses and layers of massive sulfides and an underlying discordant stockwork. Ali deposits show metal zoning. The hydrothermal alteration related to mineralization is strong and asyrnmetrical, and is found dominantly within the stockwork zone and host rocks surrounding the ores. There are two alteration patterns: (1) chloritization - sericitization - silicification from outer sides to core of the alteration pipe; and (2) silicification + sericitization - silicification + carbonate from the lower to upper part of the alteration pipe_The mineralization temperatures of ore-forming fluids vary in the range 200°C to 335°C. Thermal evolution of the fluids displays temperature profiles that first increase and then decrease with progression of mineralization processes. The majority of black-ore minerais (Groups I and II) formed during intensifying stages of hydrothermal activity, and the majority of serni-yellow-ore minerals (Group III) formed during a thermal maximum . There followed the formation of fine-grained black-ore minerals (Group IV), which interacted with barite layers during decreasing temperature phases.Oxygen and hydrogen isotope studies show that the sources of ore-forming fluids for the Kuroko­ type VMS deposits are two-fold: seawater and magmatic hydrothermal solutions, represented by the Kuroko deposits in Japan and Kuroko-type VMS deposits in Sanjiang, respectively. In the latter case the hydrothermal solutions reacted with host rocks and mixed with cold seawater percolating downward, and circulated through volcanic rocks resulting in development of alteration zones and formation of ore minerals in Kuroko-type VMS deposits."

Jan 1, 1993

By S. H. Schulz

100 YEARS AGO, on the first of August, 1877, the mining engineer Friedrich Koepe was granted the patent rights for a hoist driving ropes on the principle of friction. It was named after him: the Koepe hoist. On the occasion of this centenary, the main features of the Kcepe principle are described.

Jan 1, 1977

By S. Kelebek, U. Demir, T. C. H. Richards, E. Koss

"Laboratory-scale tests were carried out to investigate the response of a high-grade (~143 g/tonne) well-liberated gold ore to flotation using two collector types. Octyl and amyl xanthates, representing conventional types of collectors, were tested against an n-octanoic and hexanoic acids under moderate and high redox potential conditions. The latter was based upon a suggestion in literature that monocarboxylic acids are able to adsorb onto the surface of gold at redox potentials near 600 mV (SCE). This investigation did not demonstrate that these carboxylic acids could function as collectors for gold in real ores. In fact, they appear to have slightly depressed gold. However, the results demonstrated that octyl and amyl xanthates acted as highly effective gold collectors for this ore and that an increase in the collector dosage led to an increase in recovery for all mean particle sizes. In some tests, gold recoveries of around 95% were attainable in concentrates with grades around 6 kg/tonne, indicating that xanthate flotation remains a viable means of concentrating gold even at coarse grain sizes. Various aspects of the process such as grade-recovery performance and recovery by size are discussed.INTRODUCTION Three methods are used for the recovery of gold in mineral processing, either alone or in combination: gravity concentration, cyanidation and flotation. Gold occurs as a by-product in some ores together with platinum group metals and as the primary metal in other ores in the form of native gold and electrum, which are alloys of gold, silver and minor amounts of copper. Flotation is a viable method for recovering liberated gold where the gold is visible under an optical microscope (greater than 1 µm in size) and where the attachment of gold grains is not prevented due to bubble loading by competing minerals. It is generally known that grains finer than 150 µm in size will float with most collectors."

Jan 1, 2017

By Paul G. Dunn

The planning of underground mines is a complicated process involving geological, engineering and operational constraints. MIRARCO is in the process of developing a 5D Mining Exploratorium where 3D mining models are combined with time (4th dimension) and costs (5th dimension). The mining exploratorium is a collection of external and inhouse software packages specifically geared to help underground mining companies arrive at better mine plans. This paper discusses the progress made in the development of the 5D Mining Exploratorium and a change in mine planning philosophy by conducting frequent audits in a Virtual Reality Laboratory. The development of genetic algorithms for optimising stope sequences is also presented.

May 1, 2003

By T. Kerr, C. Mattich, J. Wilson

"In refractory gold concentrates, gold is occluded in sulphide minerals preventing efficient cyanide leaching. Hence, roasting is used to oxidize sulphur and organic carbon, the latter being necessary to minimize recovery loss through the preg-robbing effect. In 2009, Outotec commissioned the circulating fluidized bed roaster at Syama gold mine in Mali. Since 2013 Resolute and Outotec have been implementing improvements to the roaster performance with the capacity increasing from 8000 t/month in 2013 to above 13,000 t/month in 2016, while achieving a residual sulphide sulphur and organic carbon contents of below 0.1 wt.% and 0.4 wt.%, respectively. Thus a gold recovery in the CIL of above 90% is attained. In 2016, Outotec audited the Syama roaster. The analysis resulted in the Low Carbon Roaster (LCR) upgrade concept which (i) allows re-processing of calcine dust from the spray cooler and ESP after pelletization and (ii) allows the roasting of a further fine-organic carbon rich feed, i.e. de-slime circuit tailings. The LCR upgrade aims to reduce organic carbon to <0.2 wt.% and increase roaster-leaching gold recovery by >3%. Project development included extensive testwork. The LCR process is expected to become operational during FY 2019.INTRODUCTION Double refractory sulphide ores exhibit the characteristics of gold locked within pyrite grains, in the presence of preg-robbing natural (organic) carbon. Hence, to achieve high recovery during subsequent processing steps, i.e. cyanide leaching, oxidation of sulphide sulphur is required, producing a porous calcine by way of a roasting step. This allows for the gold contained within the pyrite grains to be accessible during cyanide leaching. Furthermore, it is necessary to oxidize the organic carbon. Oxidizing the organic carbon is essential as gold recovery loss occurs as a result of gold-cyanide complexes being adsorbed on organic carbon, this phenomenon is termed as preg-robbing (Miller et al., 2016). The gold absorbed on the organic carbon is lost, reporting to the tailings stream. Hence, the aforementioned oxidation of sulphide sulphur and organic carbon is the process goal. Nonetheless, the latter must occur at a controlled temperature which is concentrate/ ore specific, since the pores of the produced calcine should not sinter, as this makes the gold contained in the calcine less accessible during leaching, leading to gold recovery loss. The tight temperature control requirement is a decisive factor in the choice of a Circulating Fluidized Bed (CFB) as the roasting reactor, due to the excellent mixing characteristics of the CFB which results in temperature homogeneity of (+/-10°C). Roasting of double refractory ores, as described above, can be included in the flowsheet after comminution and grinding, a process termed as whole ore roasting, or by including a flotation circuit termed as concentrate roasting. Roasting the flotation concentrate results in less solid flow, increased sulphide sulphur grade and organic carbon content resulting in a higher heating value and higher gold content. A typical composition of the Syama ore and concentrate is given in Table 1. Ore average values presented correspond to the period 2015, while concentrate values are typical for the flotation performance throughout the period 2012–2015."

Jan 1, 2017

By J. G. Kelly, C. P. Brown

"In June 1983 a new borehole hoisting system was commissioned at Sherritt Gordon&apos;s Fox Mine. Twelve hundred tons-per-day of ore from the 2600 and 2800 levels are being hoisted to the 2000 level through an 8-jt diameter bored winze. This new method replaces the diesel truck haulage system which had been in operation at the mine since 1975.A study was initiated in 1980to determine the most effective method of achieving the required production. The study examined several hoisting alternatives including: expanding the existing trucking system; converting to electrically -powered truck haulage; and deepening the skip compartments of the existing main shaft. The alternative selected as the hoisting method most suited to the requirements was borehole hoisting.Development of the new system commenced in April 1982. Underground excavations included 700 feet of 8-ft diameter borehole, a hoistroom and headframe, storage bins, and a grizzly and rockbreaker station. Equipment installations included: a 5-ft diameter double-drum Nordberg hoist; a counterweighted Kimberley-type skip; two rockbreakers; and the steel sets in the winze. These installations were completed in June 1983. Some problems were encountered after the initial commissioning but these were solved, and since August 1983, the system has proven that the designed capacity is achievable within expected costs."

Jan 1, 1985

By J. Paturaud, A. G. Villemiane, J. Y. Buffiere, D. Fabregue, M. Perrier

In this work, a detailed characterization of the cyclic damage mechanisms on duty in car heat exchangers has been carried out in order to improve their reliability. The material which consists in very thin (<0.3 mm thick) sheets formed of 3 co-rolled aluminum alloys (4045 /3916/ 4045) has been brazed in order to obtain metallurgical and surface conditions representative of those of the real components. Fatigue tests at constant stress amplitude have been performed at room temperature and 120°C in order i) to characterize the cyclic resistance of the studied materials and ii) to study the effect of temperature on the fatigue damage mechanism. The mechanisms leading to failure have been identified from post mortem fractographic analysis. The Wohler curves obtained show that, contrary to common structural Al alloys, this type of thin sheet brazed multi material can be cycled for several hundred thousand cycles at very high stress level (> ~ 80 % of the tensile strength). This behaviour is analysed with respect to the microstructure resulting from the brazing process and the low number of grains present in the sample thickness (around 5 grains).

Jan 1, 2015

Discovery of an economic diamond deposit produces considerable wealth in terms of jobs, royalties, mining investment, and economic spinoffs for residents, including Aboriginal peoples. Diamond mines contribute to the GDP, increased personal income per person and reduced unemployment rates. Is it possible in Alberta?

May 1, 2008

By K. Chattopadhyay

Fluid flows in metallurgical reactors play a vital role on liquid metal cleanliness for both ferrous and non-ferrous metallurgy. Thus, it is absolutely critical to understand different fluid flow mechanisms, and the use of computational methods to model the complex non-isothermal, turbulent, single- and multiphase-flows, has to be appreciated. The present case study emphasizes on controlling the flow of liquid steel in a tundish and enhancing liquid metal cleanliness. CFD modeling was used to build a robust mathematical model, and effects of flow control furniture and non-isothermal conditions were analyzed. The mathematical model was validated against water model experiments. Parameters that were conducive for inclusion removal were identified and implemented in the plant. Some flow control devices could increase inclusion removal to a great extent compared to the existing configurations. In cases, where a hot ladle was poured into a relatively cooler tundish, inclusion removal was better, whereas results were catastrophic in cases where colder liquid was poured from ladle to the tundish. Similar techniques can be applied for other liquid metals including light metals and non-ferrous metals.

Jan 1, 2015

The Santa Rita mine is located in north eastern part of Bahia in Brazil and is owned and operated by Mirabela Mineração do Brasil Ltda. Typical SABC circuit was designed as the preferred option for the 4.0 mtpa (500tph) to produce a P80 of 125um for flotation. Although the SAG was originally designed to operate with conventional radial pulp lifters, later it was fitted with Outotec?s Turbo Pulp Lifters ? TPL (Latchireddi, 2005). The milling circuit commenced commissioning on the 24th of October 2009 and the milling circuit achieved the nameplate capacity within days. with small and relatively simple measures to rectify. Since commissioning, the SAG mill has been working in fully autogenous grinding (FAG) mode with no balls (in contrast to the estimated 10% ball charge) and has been consistently treated up to 650tph. This paper examines the comminution design process, the operating philosophies, start-up experiences, post commissioning optimization and future development works. An evaluation of mill performance relative to the design criteria for the project life to date is also included.

Jan 1, 2012

"In response to mine head grades declining and orebodies becoming more complex, Glencore Technology has developed an alternative method for recovering economic minerals once leached into solution, rather than relying on conventional flowsheet options. The method involves the precipitation and separation of base metals from solution with limestone or lime. The final grade of these precipitate is not usually high enough to attract favourable terms of sale due to dilution from gypsum and sulphate salts. A set of operating conditions have been developed to allow the separation of the base metal precipitate from gypsum by exploiting the difference in particle size. A high-grade oxide product can be easily separated from the gypsum stream at very low cost. This process was originally developed by Glencore for zinc and copper systems. This paper reports on the successful application to nickel and cobalt, and this process has significant advantages over the incumbent precipitation process utilising magnesia.INTRODUCTION During evaluation of transitional and oxide zinc ore deposits during the 1990’s, Noranda Inc. (now Glencore) developed a sulphate based ore leach process to extract zinc into solution. For flowsheet development, conventional schemes dictated that once the zinc was dissolved in an acidified solution it was recovered by means of purification or solvent extraction followed by electrowinning and casting to produce zinc ingots. The deposits Noranda evaluated were high grade but had a relatively short mine life (10 years) and economic analysis showed that the projects couldn’t sustain the investment of a full zinc refinery. Compounding this problem was the lack of power supply infrastructure and the high power cost in the region. Noranda then evaluated alternative means of recovering zinc from solution. Laboratory testwork showed that a high-grade zinc precipitate (+50 wt% Zn) could be produced as an oxide, carbonate or sulphide by contacting acidified zinc sulphate solution with a number of reagents including soda ash, sodium hydroxide, and sodium hydrogen sulphide. Economic evaluation showed that the cost of the reagents are prohibitive, especially when the final product is still a metal intermediate (ZnO, ZnCO3 or ZnS). Noranda then continued to focus on fine zinc oxide precipitation for supply into the automotive tyre industry as this product would attract favourable terms of sale as a premium on Special High Grade (SHG) zinc."

Jan 1, 2017

By T. Crivits

"Freeze lining technologies are used industrially to protect the integrity of furnace walls in pyrometallurgical reactors. This is achieved by solidifying a protective layer of slag on the inner furnace wall. In the current study, laboratory experiments have been undertaken to produce freeze linings in ‘Cu2232 O’-‘FeO’-MgO-SiO slags under controlled conditions using an air-cooled probe technique. Whilst most thermal models of freeze linings have assumed the freeze lining-bath interface to be at the liquidus temperature of the bulk bath and to be planar in geometry, the current research has demonstrated that this is not the case. Experiments undertaken using this high-temperature slag system have shown the interface at steady state conditions to be at subliquidus temperatures. The solid phases present at the interface do not include the primary phase and the interface is non-planar. The study indicates the need for improved understanding of the fundamentals of freeze lining formation, and of the influence of system properties and process parameters"

Jan 1, 2015

By C Carbonneau

In order to successfully produce columbium pyrochlore concentrates, St. Lawrence Columbium and Metals Corporation had to face two principal problems met in several new operations but possibly made more acute than usual owing to the newness of the project. 1.-The ore is particularly complex, as it is made up of an elaborate intermingling of carbonates and discontinuous ultra-alkaline rock bodies of various ages and types in which no less than seventy mineral have been re-ported. Obvious petrographic or structural controls are lacking. Ore boundaries have to be defined on the basis of assay results and the determination of several minerals which occur in trace amounts. 2.-The pyrochlore concentrates produced had to com-ply with a set of stringent specifications. This fact, combined with the low Cb205 content of the ore, necessitated the use of a beneficiation process that would have to operate at a concentration ratio greater than 100:1. A brief description of the mill circuit is given. Mill stability was obtained through extensive mineralogical study of the mill feed coupled with close geological and engineering control of the mining operations.

Jan 1, 1965

By Seshadri Seetharaman, Nurni N. Viswanathan, Haijuan Wang

The present work aims at some process modifications in specified metallurgical processes, wherein CO2 can be used successfully as an oxidant for decarburization in steelmaking and applied in some non-ferrous metals production processes. During the decarburization of Cr-containing high alloyed steels, the present researchers investigated the possible use of CO2 instead of Ar-O2 mixture and could successfully decarburize the steel melt without significant loss of alloyed Cr to the slag phase. A mathematical model was developed based on the bubble formation accompanying the chemical reaction: C(molten steel)+ CO2(gas)= 2 CO(gas). The model predictions were tested by laboratory scale (1 kg) experiments carried out in an induction furnace and very good agreement between the model predictions and experimental results were observed. A national project has been sanctioned in China for the implementation of CO2 in decarburization of ferroalloys as well enable the addition of pig iron in the electric arc furnace process when the scrap supply is limited. New processes have been developed for the utilization of CO2 in the case of non-ferrous processes. A novel method of treatment of Al dross by leaching with water and capturing the evolved NH3(formed by the hydrolysis of AlN) has shown very promising results.

Jan 1, 2015

By D. W. McDonald, N. A. Duke, R. L. Hauser

"Abstract- The NERCO Con Mine is situated in the amphibolite facies aureole of the Western Plutonic Complex overprinting the Yellowknife Greenstone Belt. Metamorphic grade of the upright monoclinal basaltic succession decreases from hornblende-amphibolite facies along the border of the batholith to greenschist facies. Metamorphic isograds, subparalleling the faulted margin of the batholith, transect volcanic stratigraphy and coincide with major gold­ bearing shears.Gold mineralization is confined to north-striking, west-dipping shear zones where hanging­ wall amphibolite facies mineral assemblages retrogress to chlorite-carbonate-sericite-sulfide bearing schists hosting multiple generations of quartz-ankerite veins. The gold-producing portions of the Con and Campbell Shears occur where these structures transect an east trending thermal corridor. The corridor is defined by granitic plugs and a number of related breccia bodies, that can be traced outwards from the batholith across the greenstone belt.Prograde reactions of greenstone during amphibolitization effectively liberate fluids that partition metals. With retrograde reactions at shear zones, gold is precipitated with quartz due to the destabilization of sulfide and arsenic complexes. The coupling of regional prograde metamorphic and restricted retrograde metasomatic overprints suggest mineralization is temporally related to emplacement of the Western Plutonic Complex. Economic gold concentrations within the intrusive corridor indicates enhanced metamorphic overprint of hornfelsed greenstones enveloping satellite intru sives peripheral to the main batholith."

Jan 1, 1993

By G. F. Liu, S. Owada

Platinum Group Metals (PGMs), Pt, Pd, Rh, have been widely used as a three-way catalyst to clean discharged gas from automobiles and therefore a considerable amount of the spent catalysts is generated annually. This paper proposes a novel concentration technology of PGMs by utilizing the double-deck structure of PGM bearing alumina-ceria and cordierite phases. The applied technologies are a combination of heating-quenching, selective grinding and screening for separating alumina-ceria phase from cordierite. Temperature change as a function of quenching time and the thermal stresses applied to both phases were simulated and calculated by FEM, and it was clarified the mechanism of micro-cracks generation at the phase boundary and micro-cracks in alumina-ceria phase, which indicated that separation of alumina-ceria phase from cordierite and selective breakage of alumina-ceria phase could be achieved in the subsequent selective grinding with an attritor. This process could concentrate 46 wt% of alumina-ceria phase into fine fractions with 86 % recovery efficiency. The remaining alumina-ceria phase can be further recovered by applying flotation and so on.

Jan 1, 2015

By G. K. Herzog

THE problems relating to the construction and use o{ mining equipment are basically the same as those pertaining to equipment in other industries. It is true that much mining equipment is subjected to an unusually severe combination of shock, high stresses, abrasive wear, and corrosive ? conditions, but in other industries, also, equipment must operate under similar adverse conditions, so that their experiences may readily be applied to the problems of the mining industry. Steel and iron are for obvious reasons the most suitable materials for the construction of the greater part of the equipment used in the mining industry. For a large percentage of uses, the ordinary plain carbon-steels and ordinary or unalloyed cast-iron are, and probably will continue to be for a long rime, entirely satisfactory materials. There are, however, many. conditions which cannot be satisfactorily taken care of by these materials, and alloy steels and irons must be used where the greatest possible economy is desired. In general, alloy steels and irons are used where it is necessary or economically desirable to use materials possessing properties superior to plain carbon-steel or ordinary cast-irons, such as: (a) better strength (b) better wear resistance (c) better corrosion resistance (d) better resistance to high temperatures (e) better resistance to low temperatures or combinations of two or more of these advantages. There are also conditions where materials having other special properties are required, such as, for example, certain magnetic or electrical properties for electrical machinery; but in the great majority of cases, one or more of the five advantages listed are the most desired.

Jan 1, 1938

By Jaeheon Lee, Junmo Ahn, Doyun Shin

"Many alternative leaching systems including bacterial leaching have been introduced to avoid passivation on the surface of chalcopyrite and to increase the leaching efficiency of copper from chalcopyrite. Recently, glycine, one of the simplest amino acids, has been emerging as an efficient and environmental-friendly lixiviant to recover copper. In the present study, an alkaline glycine–peroxide lixiviant system was used to leach copper from chalcopyrite concentrate and the leaching mechanisms were also investigated by a suite of kinetic studies under different conditions. The chalcopyrite concentrate contains 28.8% copper with 30.8% sulfide sulfur. The effect of concentration of glycine and hydrogen peroxide of the leaching solution was investigated. Glycine concentration was varied from 0.5 to 1.0 M and the hydrogen peroxide concentration was changed between 3 to 5%. Leaching time and pulp density were also varied. Hydrogen peroxide is an oxidant of the system and the leaching efficiency with periodic additions of the peroxide was also studied. A mineralogical study was performed using XRD and SEM. To investigate the surface of the residue materials, XPS was used to see if any passivating layer was formed during the leaching. Detailed results from mineralogical, chemical, and metallurgical studies will be presented and discussed.INTRODUCTION The greatest global resource of copper is low-grade chalcopyrite and heap bioleaching may be the only economic option for its processing. However, formation of a passivating layer on the surface of chalcopyrite slows down the oxidation reaction and reduces the efficiency of the process."

Jan 1, 2017

By V. C. Pandolfelli, L. Paulino, C. E. Zangiacomi

The continuous improvement in aluminum industry over the last years has increased metal output at lower cost. The potlining plays an important role in this regard due to high cost involved and more recently in its environmental aspects. In order to increase potlife and thus minimize the aluminum cash cost, a systemic approach is needed, through investigating the main cathode failure mechanisms by using a pot autopsy as a powerful tool, and then making the necessary chances to achieve extended potlife. In addition, preheating and pot start-up may also damage the cathode if not performed with an appropriate technique or even if the lining materials are not specified correctly, among other factors. All these aspects will be presented and discussed in this paper. Increased potlife, especially now that the current is reaching values up to 300kA, will allow aluminum plants to match their goals more efficiently at lower costs.

Jan 1, 2006