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By M. Rigaud, K. Sankaranarayanane, X. Zhou

The effect of varying fine alumina/ultra-fine alumina ratio on the Bingham to dilatancy transition in alumina based, self-flowing refractory castables has been studied in detail employing rheological tests and particle size distribution measurements. Analysis of flow resistance and torque viscosity values has shown that Bingham to dilatancy transition is strongly influenced by fine alumina/ultra-fine alumina ratio in the castable, as well as by the nature of ultra-fine alumina. The calculated values of rheological constants and the viscosity coefficient were found to increase at higher fine alumina/ultra-fine alumina ratios.

Jan 1, 2004

By L. Nutter, J. Clancy

"Barite is used extensively by the oil and gas well-drilling industry as a weighting agent. It is particularly well suited for drilling mud because of its qualities; it is non-abrasive, heavy, virtually inert chemically, easy to handle and inexpensive compared to other available heavy materials. Increased deep well drilling in Western Canada, and especially in the Arctic regions, could dramatically affect the demand for barite through this decade. Known deposits in northeast British Columbia are possible sources of incremental barite supplies, should the situation develop.IntroductionThe purpose of this report is to examine the opportunities for expanding barite production in British Columbia. Of primary interest will be the relationship between the projected future levels of production and consumption of barite in Western Canada and the extent to which increased domestic production could replace the need for imports in filling any expected supply shortages.After a brief overview of the nature and uses of barite and some of the relevant features of the barite supply industry, the discussion will turn to the supply gap in the Canadian market and the possibilities for import substitution.OverviewBarite is an industrial mineral which is used in large quantities by the oil and gas well-drilling industry. It is often an important component of drilling mud, a fluid circulated continuously in the well during the drilling process to lubricate and cool the drilling apparatus and to contain the high oil and gas pressures found at depth. Barite (BaSO4) is particularly well suited as a weighting agent for drilling mud because it is a heavy (specific gravity to 4.5) inert mineral which is inexpensive in relation to other materials having a high specific gravity. In the on-site use of drilling mud, ground barite is combined with numerous other solid ingredients and chemicals in the form of a slurry. Other advantages of barite include cleanliness, ease in handling and its non-abrasive character (hardness of 3-3.5)."

Jan 1, 1982

By G. R. Tostengard

"The paper identifies functional areas which frequently can yield significant productivity improvement. Emphasis is placed on the repair and maintenance, material supply and training functions. Successful approaches are discussed in some detail, and typical results which have been achieved are reviewed.IntroductionA challenge which at all times confronts the manager o f any mineral operation is the potential to improve his operation no matter how effective it might be a t the present time. The challenge has been present through my entire lifetime and I suspect a good many years prior to that and, I expect, will continue many year s and decades in the future. The competitive and economic situation in which we in the minerals industry find ourselves today makes the challenge eve n more important during the 1980s. In many cases it’s a question of survival, not simply pr of it improvement.There are, of course, many avenues to improving profitability; technological changes, new equipment and facilities, improved products, improved mine plans, etc. All of these are important and must be addressed by each manager. This paper focusses on just one avenue to improvement and that is ""improved management"", not so much of management at the boardroom level but of improved management o f the facilities and workforce as the y currently exist. Management implies control. There are three areas where control is often found lacking:1, Repair and maintenance of equipment and facilities;2. Material supply including procurement, inventory control and warehousing; and3. Training.These three areas are all complex and difficult to manage and they are all but ignored in the formal education which our industry's manager s normally receive. They are areas which can be improved with relatively small investments and therefore, they represent especially attractive improvement targets during the 80s when, for most of us, investment dollars are very difficult to come by."

Jan 1, 1983

By Desmond M. Connor

"The State of the EnvironmentRecent data from a State of the Environment report prepared in January 1991 and released in April (see references) , indicates that the physical and biological environment across Canada is deteriorating in some important ways. For example: • emissions and atmospheric levels of CO2 are rising at a rate more than 50% of the U.S. increase; global temperature continues to rise, especially during the last decade;• while S02 emissions have been falling since 1984, NOz has declined only slightly since that time; N02 in Canada rose 43% during 1970-87, compared with a 7% rise in the U.S.;• municipal discharges of phosphorus and BOD (biochemical oxygen demand) to fresh water have been rising steadily since 1983);• pulp and paper mill discharges to fresh and Pacific coastal waters have been rising, 1970-87;• migratory game bird populations (Prairie Mallard, Northern Pintail) have been declining for the last 20 years;• total per capita energy use continues to climb.The State of the PublicSimilarly, data from recent public opinion surveys shows that public concerns about the environment are either rising, or are remaining at a high level despite the competing claims of the economy and political events for attention.For example, Professor Reginald Bibby's national survey this year shows that Canadians rank our top three issues as theeconomy, the environment and government incompetence.An Angus Reid survey commissioned by the Mining Association of Canada and other mining organizations in 1989 showsthat, despite general support for its economic benefits:• 67% of the general public perceive the mining industry to be a major source of pollution and environmental contamination;• 68% believe that a new mine should not be developed if it will disturb local wildlife;• 52% would prohibit a new mine if it required a road through a national park;• 49% would disallow mine development if it took as much land as an average farm in an agricultural area or if it limited sports fishing in a local lake."

Jan 1, 1991

By G. Morin, S. Amira, F. Chiesa, B. Duchesne

"The effect of heat treatment on the stress corrosion cracking (SCC) resistance of A206 aluminum alloy was studied using the breaking load test according to ASTM G139 standard. This method uses the residual strength measurement from tensile test specimens previously stressed axially while exposed to the 3.5% NaCl alternate immersion test according to ASTM G44 standard. The residual strength after exposure is used as a measure of SCC degradation. The performed heat treatments were conventional natural aging T4 and artificial over-aging T7 tempers in addition to artificial aging T6 temper added for purpose of comparison. These tests showed that A206-T4 has a good resistance to SCC at pre-loads up to 100 MPa while A206-T7 was prone to SCC for pre-loads of 0 and 50 MPa, and showed total loss of ductility for pre-load of 100 MPa. Both A206-T4 and A206-T7 pre-loaded at 150 MPa showed poor resistance to SCC. A206-T6 showed the worst susceptibility to SCC as it lost all mechanical resistance at the end of the alternate exposure to 3.5% NaCl solution, even without any applied pre-load. Metallographic analyses showed that the resistance of A206 alloy to SCC is mainly affected by the transition from pitting to intergranular corrosion attack. The initiation and the propagation of intergranular corrosion attack might be assisted by high stress concentrations in the pits, particularly for pre-loads higher than 100 MPa. The transition from pitting to intergranular corrosion can also be promoted by hydrogen evolution from growing pits, which supports crack propagation by hydrogen embrittlement.INTRODUCTIONA206 aluminum-copper casting alloy offers ones of the best mechanical properties among the aluminum foundry alloys. This alloy belongs to the 206 alloy family developed in 1970s as an alternative to the highly resistant and ductile but more expensive Ag containing 201 alloy (Tiryakioglu, 2009). A206 showed also good low cycle fatigue strength (Sigworth, 2002). These properties made A206 alloy a strong candidate for some vehicles lightweighting applications. In spite of its interesting properties cited above, A206 alloy was rarely used in critical applications due to its tendency for hot tearing and stress corrosion cracking (SCC). Studies of A206 hot tearing behavior showed that this tendency can be reduced by improving castability and by grain refinement (Sigworth, 2002). The optimisation of the casting design can also prevent the tendency toward hot tearing. The SCC of aluminum-copper alloys arises from their susceptibility to localised corrosion, especially in chloride containing media. The localised corrosion in Al-Cu alloys is caused mainly by their heterogeneous microstructure, where the presence of many phases leads to the formation of micro-galvanic coupling with the matrix. However, most of the studies aimed at investigate the SCC of Al-Cu alloys concerned the wrought ones, especially the AA2024 alloy tempered in the T3 (or derivative) condition and few studies concerned the 206 and cast alloys in general (Alexopoulos, 2009 and 2016; Campestrini, 2000; Vogt, 1998; Talamantes-Silva, 2008; Zhang, 2003). Jean et al. (Jean, 2009) studied the effect of heat treatment on SCC behavior of B206 alloy using alternate immersion technique and grain boundary attack method and did not find direct correlation between the two methods. Another study showed that aging of 206 alloy may make a casting susceptible to SCC (Sigworth, 2002). However, these studies did not provide detailed information about the mechanisms of SCC of 206 alloy, as well as the effect of the stress intensity. The present work investigates the effect heat treatments and the stress intensity on the morphology of the corrosion attack and the SCC behavior A206 aluminum alloy. This study uses the breaking load test according to ASTM G139. This test utilizes direct tensile specimens and was developed to give a more quantitative measure of the SCC performance of resistant aluminum"

Jan 1, 2016

By George R. White

"The Phalen Colliery, the Cape Breton Development Corporation's flagship, is now producing thermal and metallurgical grade coal in Eastern Canada's Sydney Coal Field. The colliery is a drift mine operating under the waters of the Atlantic Ocean. Improved mechanization, including a 2200 tonne per hour cable conveyor, and the introduction of modern retreat longwall mining methods as part of the Phalen concept are now paying off in better productivity and low operating costs. Geological conditions within the coal field are consistent with plans for ever greater outputs in the 1990s. Although much of the current production improvement is related to uprated machine capacity and simplified mines planning there is potential for even further development in the areas of maintenance, process control and engineering. Human resource development will also be a key factor. These programs are now well under way and Phalen Colliery is poised for top results in the 1990s. Comparison of the CBDC's top producer with similar operations elsewhere in the world, quantifies that potential.IntroductionAn exciting new mining project which has recently started production on Canada's East Coast has been conceived and designed to be one of the most modern and productive coal mining operations in North America.As with all mining operations, the business is basically that of material transportation. Daily, the product is transported many kilometres from the underground face to the surface and then to washing facilities. Men, materials and equipment are transported to and from the surface and the operating faces and services, such as electrical power, ventilating air, fresh water, discharge water, communications and compressed air are supplied throughout the operation to cover operating requirements. On all accounts the operation has been designed to take advantage of the latest proven technology."

Jan 1, 1990

By C. A. Petch

Abstract - The High Lake polymetallic deposit is located in the northern Slave province, 40 km south of Coronation Gulf, Nunavut. The main zone, the AB zone, hosts an estimated resource of 3.56 Mt grading 5.0% copper, 1.1% zinc, 0.06% lead, 1.7 g/t gold, and 18.2 g/t silver. Archean felsic metavolcanic and metavolcaniclastic rocks are the dominant rock type and are associated with lesser mafic metavolcanic and carbonate-rich metasedimentary rocks. The sequence strikes north-northeast, dips steeply to the west, and is truncated to the west by a large granodioritic intrusion. The mineralization at the AB zone is comprised of massive and stringer chalcopyrite-sphalerite-pyrrhotitepyrite± galena. At the core of the mineralized zone, intensely chlorite-altered rocks are locally metamorphosed to form distinctive zones of anthophyllite-magnetite-cordierite-altered rock. Peripheral to the mineralized core, alteration consists of sericitization, silicification, and weaker chloritization. Primary morphology and facing direction of the zone are difficult to interpret in part due to poor primary metal zonation of the deposit. However, the irregular shape of the mineralized zone and the erratic zones of zinc enrichment at the fringes are consistent with the interpretation that the zone was formed by the replacement of a porous volcaniclastic pile.

Jan 1, 2004

By J. P. Sims

Abstract - Ultramafic to mafic igneous intrusions of the Las Aguilas district form part of a belt of generally mafic plutonic bodies within medium- and high-grade early Paleozoic metamorphic rocks in the southern Sierras Pampeanas region, Province of San Luis. The intrusions host the largest known nickel sulfide resource in Argentina and contain significant Cu, Co and PGE mineralization (2.2 Mt at 0.5% Ni, 0.5% Cu, 0.035% Co). Sulfides at Las Aguilas Este, one of two principal mineralized zones, are hosted by a body comprising subvertically dipping units of predominantly orthopyroxenite and melanorite cumulate, with lesser dunite, harzburgite, norite, leuconorite, and amphibolite. The units are zoned horizontally from ultramafic to mafic compositions, representing primary magmatic zonation away from an original base or side of the intrusion. Intercumulus nettextured and disseminated aggregates of pyrrhotite-chalcopyrite-pentlandite are concentrated in the peridotitic zones and extend into melanorite. Whole rock major and trace element compositions, and olivine chemistry, indicate that the parent magma was gabbroic/basaltic with 100 (Mg/Mg+Fe) near 59, and resembles tholeiitic magmas generated in subduction-related arc, or back-arc settings. Unusually aluminous Cr-bearing spinel is compositionally similar to those in some synorogenic mafic/ultramafic plutons in magmatic arc settings. Relatively Ni-depleted olivines and low Cu/Pd ratios are indicative of magmatic sulfide segregation early in the crystallization of the magma. Early orthopyroxene saturation and virtual lack of clinopyroxene, in conjunction with sulfur isotope values up to +6.6 ‰, spinel compositions, and presence of graphite, phlogopite and magmatic hornblende, all attest to probable crustal contamination of the parent magma. Assimilation of crustal sulfur may have been crucial in the early attainment of sulfide saturation and resultant formation of magmatic Ni-Cu sulfide mineralization. Fabrics, textures and mineralogy of the intrusions and country rocks and U-Pb zircon dating indicate syntectonic-synmetamorphic emplacement at 478±6 Ma during the Famatinian (Ordovician) orogeny. Minor to locally significant recrystallization and deformation of mafic-ultramafic rocks and redistribution of sulfides and PGE occurred during and following the Famatinian orogeny. The Las Aguilas intrusion is one of several tholeiitic mafic-ultramafic intrusive complexes within an Ordovician arc - back-arc system in the Sierras Pampeanas. Aeromagnetic datasets and regional mapping suggest there is further potential for intrusion-hosted Ni-Cu mineralization along this eroded magmatic arc.

Jan 1, 1999

By Mauricio Olivares

About Largest combined Phosphate and Potash company in the world Corporate headquarters in Plymouth, Minnesota Publicly traded on NYSE under MOS

Aug 1, 2013

By Raj Thamburaj, Li. Ping, Prakash C. Patnaik

"An effective prognosis system for aircraft engines may involve the application of a wide range of technologies and methodologies, which may include: - On-line, real-time and in-situ non-destructive inspection/detection/sensoring - Aircraft/engine instrumentation - Airborne data recording system - Advanced signal filtration - Data compression technologies - On-line engine health monitoring technologies - On-line engine component life usage monitoring technologies - Mission severity analysis algorithm based on life prediction and damage tolerance analysis models - Life assessment methodologies - Optimized repair/overhaul/maintenance planning - Optimization of mission assignment and homogeneous life usage - Web-enabled information delivery and sharing system - Decision making logistics This paper will demonstrate some efforts that Orenda has accomplished over the last decade in collaboration with the Institute for Aerospace Research of National Research Council Canada and the Department of National Defense. The presentation will focus on the following projects:"

Jan 1, 2004

By Greg Johnson

Maintenance needs information about assets to optimize availability and production needs information about performance and consumption to maximize output. In considering both these needs together as, ?Asset Optimization?, the information systems that support them are critical. The theory of Asset Optimization derives from the Lean Manufacturing concepts developed by Toyota, but some changes are required to apply this to mining operations. In particular, mining operations require automated systems due to their geographic spread and they need a strong emphasis on capturing under-performance losses as well as delays and stoppages in production. Leading metal miners and coal miners alike have applied these systems to good effect in the last 10 years. The concepts developed initially in minerals processing plants are now being applied to the mines themsleves as well as the mining logistics chain. Production increases of 5?10% are achievable with the right implementation and consideration of the some key lessons learnt in the last 10 years. Putting these lessons into action is one key step in the goal of optimizing asset performance and thus utilizing the resource at lowest cost.

Aug 1, 2013

By Gabriel Zarate

"Los Bronces had two ROM dump leach operations designated Leach I and Leach II. Leach I was commissioned in 1998 and stopped in 2014 due to the mine requirements. Leach II plant, commissioned in early 2002, was built to treat around 700 million tons of marginal ROM ore averaging 0.45 % total copper. The mineralogy of this material was estimated to be 70% chalcopyrite, 20% chalcocite/covellite and the balance oxides.The original electrowinning plant design capacity for copper production was nominal 19,500 tonnes per year at a current density of 276 A/m2 and a current efficiency of 92%. Presently, Los Bronces San Francisco plant typically operates at current densities between 390 and 440 A/m2, much higher than the average in the industry, with current efficiencies around 93% and a maximum copper cathodes production of 37,200 tonnes per year.In order to accomplish these achievements, a number of modifications in the process conditions, in the cell hardware and in the operational procedures have been implemented. In the first case, the specific flowrate, copper concentration and temperature of the electrolyte were modified to accommodate the operational requirements facilitating the increased current density. Associated with the cell hardware, a six cells expansion was added, upgraded equipotential inner cell busbars were installed and the cross section of the cathode hanger bars was enlarged for increased current carrying capacity. Documented operational procedures like short circuit detection and cathode weight control were improved.The modifications implemented and the results obtained are discussed in this paper.INTRODUCTIONLos Bronces Division of Anglo American Chile is located up in the Andes Mountains, northeast of Santiago. It had two cathode plants, Los Bronces at an altitude of 3500 meters above sea level (m.a.s.l.) commissioned in 1998 and closed in 2014 and San Francisco at an altitude of 2800 m.a.s.l. and in operation since 2002.The process is leaching run off mine (ROM) low grade copper sulphide ore in dumps. The mineralogy of this material was estimated to be 70% chalcopyrite, 20% chalcocite/covellite and the balance oxides. The average grade is 0.45% total copper (Cut).At Los Bronces dump, Leach I plant, the pregnant leach solution (PLS) was collected and stored in an underground reservoir. From there, it was fed to a solvent extraction plant with a series-parallel configuration in two extraction stages and one stripping stage. The electrolyte produced was fed to the electrowinning plant having 30 cells and 60 cathodes per cell. Maximum capacity of this plant was 12,000 tonnes per year (tpy)."

Jan 1, 2016

By F. J. Munn

"Since 1976, Cardinal River Coal s Ltd. has completed mining in eight pits. In each of these pits, at least one wall has failed, none by design, although not totally unexpected, yet there was no loss of production nor risk to personnel or equipment. Cardinal River Coals Ltd. has been successful in implementing a program to cope with failures and now feels justified in adopting more optimistic design parameters.The wall control program at Cardinal River Coals Ltd. is based on the premise that the walls are going to fail, monitoring is to confirm when. The program consists of monitoring slope movements and piezometric levels as well as structural mapping and visual inspections. In case of excessive movement, the frequency and intensity of the monitoring is increased. If a failure is impending, suitable remedial action is undertaken such as cutting down the crest, building up the toe, depressurization of the wall, artificial support, or a combination of the above. If remedial action is not possible, monitoring permits operations to continue up to near the time of failure.At the design stage, the emphasis is on identifying the potential failure mechanisms and the con sequences of failure. Once the potential failure mechanisms are identified, a monitoring system can usually be employed to give sufficient response time, and providing the consequence of failure is not severe and/ or remedial action can be taken to arrest the movements, then it is practical to mine pit slope s which have a higher probability of failure."

Jan 1, 1985

By M. R. Babcock

"The Rabbit Lake story began in the late sixties and will continue well into the twenty-first century. It is a story of success, of multiple ore body discoveries, of unique systems, and new methods made possible through innovative and state-of-the-art design. Two quite different geological systems host the five ore bodies mined, or slated to be mined. These two systems have yielded two distinct ore types, each with characteristic mineralogical properties and each requiring its own specific mill circuit.Emphasis on communications and our unique systems have led to a satisfactory and fulfilling work environment resulting in the historically low employee turnover which has contributed to the operation success.A comprehensive environmental study after twelve years of operation has given the Rabbit Lake Operation a completely clean bill of health. INTRODUCTIONRabbit Lake can be described as Saskatchewan's first highgrade uranium mining operation, which set the stage for the province's current role as the leader in uranium mining throughout the western world. The importance of the Rabbit Lake operations - past, present and future.LocationThe Rabbit Lake operation is located in northeastern Saskatchewan (Fig. 1)- 805 km north of Saskatoon, Saskatchewan, and 814 km northeast of Edmonton, Alberta. OwnershipGulf Minerals Canada Limited discovered the Rabbit Lake deposit in 1968. Mining operations began in 1975and were operated by Gulf until purchased by Eldorado Nuclear Limited in 1982. In 1988, Eldorado merged with Saskatchewan Mining Development Corporation (SMDC) to form Cameco-A Canadian Mining &. Energy Corporation. The new corporation is one of the world 's largest uranium companies.Cameco's $1.5 billion in assets include the Rabbit Lake uranium mine (Cameco 100010); the Key Lake uranium mine (Cameco 66.67%; Uranerz Exploration and Mining Limited 33.33%); the Cluff Lake uranium mine (Cameco 20%; Amok Ltd. 80%); the Fuel Services Division at Blind River and Port Hope, Ontario (Cameco 100%); and a 100%); and a 48.75% interest in the Cigar Lake uranium deposit which is now at the test mining stage (Cogema Canada Ltd . 32.625% ; Idemitsu Uranium Exploration Canada Limited 12.875%; Corono Grande 3.75%; Korea Electric Power Corporation 2%). In addition, Cameco is involved in a number of base and precious metal explor ation projects."

Jan 1, 1989

By J. C. Thornley, H. L. J. Drummond

"Fifty years of wear on the original carbon steel shaft of this hydro turbine necessitated repair operations in 1980. Both austenitic and martensitic stainless steels have been used individually as journal materials in separate trials on an80-inch long and 22-inch diameter radial bearing but neither one nor the other has been successful.The wear and cracking problems of the stainless steels leading to the present abandonment of both classes of stainless steel are described. In particular the dependence of the toughness of type 410 stainless steel on its tempering temperature and the susceptibility of that steel to quench cracking are highlighted because problems have been caused by both of these metallurgical factors.IntroductionAs part of a desire to improve the efficiency of a fifty-year old hydro-electric generating station on the Saint John River, the decision was made to change the journal and bearing material for the shaft bearings, which are stave-type bearings. For the initial fifty years of operation the bearings had been wooden (lignum vitae) and had run on the carbon steel shaft directly. For one of the four unit s at this station the performance of this combination has been truly excellent, and the remaining three sets of bearings had performed well. However there had been shaft wear on the units and the wear had made the shafts somewhat elliptical when a decision was made to install some sort of new journal on to three of the old shafts. [In addition to the wear on the carbon steel journals it was found that one shaft was significantly softer in the bearing area than it was immediately above the bearings (180 Vickers in comparison with 230 to 250 Vickers)] ."

Jan 1, 1985

By P. R. A. Andrews

"A sample of flotation feed from Bakertalc Inc., High water, Quebec was subjected to flotation evaluation to improve the recovery of talc. A number of alternative frother/collectors and depressants as well as flotation parameters including pH, conditioning time, frother/collector concentration and pulp density were assessed. In addition, the possibility of using a size coarser than that currently employed for flotation (95% minus 50 um) was investigated.As far as possible, a laboratory duplication of the present circuit arrangement was folio wed so as to minimize the cost of any changes. The best results obtained were a concentrate analyzing 95.96% acid insol for a recovery of 65.98% after four stages of cleaning. With recirculation of cleaner tailings, the recovery would be higher.The possibility of using an alternative method, based on the natural ability of talc to float unaided by a frother/collector, was briefly explored with encouraging results.IntroductionBakertalc lnc ., located in the eastern townships at Highwater, Quebec, Is approximately 140 km east of Montreal near the Vermont, U.S. border. Originally called Baker Mining and Milling Co. Ltd., it has produced pulverized talc products since 1938(1 ), although records show that talc was mined in the area as early as 1871(2). Feed to the mill originally was obtained from local deposits, but since 1952 the van Reet mine near south Bolton, approximately 25 km from Highwater, has been the source of ore .In 1957 a Raymond high -side roller mill was installed which enabled production of a greater range of talc products and, in 1960, new crushing equipment and a dryer were added. Other additions to the mill were the introduction of wet magnetic separation, although this was later discontinued, and flotation to produce high-grade talc concentrates."

Jan 1, 1985

By Craig H. B. Leitch

"In describing the alteration of porphyry systems, the term ""secondary K-feldspar"" appears to be an oversimplification. A better term would be ""alkali feldspar"" alteration, because in actual fact the replacement feldspars show gradational changes from an albite, which is important in some systems, to an alkali feldspar containing minor orthoclase molecule, to true orthoclase.There are several textural varieties of secondary alkali feldspar present in the porphyry systems studied from British Columbia, Australia and New Zealand. These include, in apparent increasing order of alteration intensity: clear albite (An10); patchwork albite (An5-10); chessboard albite (An0-10); ""irregular albite "" (An0Ab100 to Ab90Or10); untwinned ""anoralbite"" (Ab90Or10 – Ab70Or30); and orthoclase (Ab40Or60 - Or100)·The exploration significance of these varieties of alkali feldspar is that their gradation in composition, from sodic to potassic, may be linked to a corresponding increase in intensity of alteration. Thus, there is a tendency for more sodic alteration feldspars to characterize weak, sub-economic deposits, or the fringe zones of stronger deposits; the more potassic alteration feldspars may provide an exploration vector toward more highly mineralized zones."

Jan 1, 1981

By Wenbin Zhang, George W. Poling

"Prior or simultaneous addition of ammonium sulphate can, not only enhance the activating effect of hydrosulphide ions on xanthate flotation of malachite but it can also eliminate possible detrimental or depressing effects of excess residual hydrosulphide . Use of relatively inexpensive ammonium sulphate appears to reduce the consumption of the much more expensive sulphidizing agent for optimal flotation recovery INTRODUCTIONOxidized copper minerals float poorly with conventional thiol-type collectors. This is believed to be due to the nonadherent character of the collector coating, which is readily re- moved by particle abrasion. Rosas and Polingr reported emulsion flotation seemed capable of resisting abrasion during the flotation of non-sulphide copper ores. It appears that the most common flotation technique for oxidized copper minerals comprises sulphidization with Na .S and subsequent treatment by sulphydryl collector. The principles of this method are available . Malghan recently reviewed the studies on the role of sodium sulphide in the flotation of oxidized copper, lead and zinc minerals.It is well known that in the sulphidized flotation of malachite, the activation process depends strongly on the concentration of the sulphidizing agent, i.e., insufficient sulphide gives poor recoveries because of inadequate sulphidization; excessive sulphide also causes poor recoveries due to the depressive effect of the residual hydro-sulphide ions in solution. A major difficulty in sulphidization, especially with a varying feed nature, is to establish and maintain the optimum sulphide concentration in solution. In plant practice, vigorous control of sodium sulphide is required and stepwise addition of the reagent is recommended to improve the efficiency of the process. Soto and Laskowskim have found that malachite, depressed by an excess of sulphide ions, can restore its floatability if air or oxygen is introduced to the pulp. They attributed this to the oxidation of the HS - ions on the surface of the mineral. Jones and Woodcockuvi showed that a sulphide ion selective electrode could be used to optimize the conditions (e.g . amount of hydrosulphide, sulphidization time, flotation time) more readily and precisely than existing methods in the flotation of oxidized copper ores."

Jan 1, 1989

By G. Kachaniwsky, M. Bédard

"The Noranda Continuous Smelting Process at the Home smelter was commissioned in March 1973. The ability of the process to handle a wide variety of feed materials and a steady stream of technical innovations in recent decades has served to maintain the Home as an efficient and versatile custom smelter. This paper reviews recent technological development and capabilities in areas such as sampling and preparation of secondary and complex materials, as well as the smelting and related environmental control issues. Future trends and improvements are also addressed.IntroductionThe Noranda Home smelter commenced operations in 1927. It was originally designed to treat 910 tonnes per day of copper concentrates and ores coming from the new Home mine site. In the 19305, the company opened its doors to other mines in northwestern Quebec. Treatment of feed materials on a custom basis has, therefore, always been an important factor in the operation of the Home smelter. Throughout the years, the Home gradually increased its custom smelting capacity, while maintaining its production from the Home mine. By the early 1950s, 65% of the materials processed was from outside customers, and by 1974, this figure had increased to more than 85% . With the closure of the Home mine in 1976, the company extended its smelting operations beyond ore and concentrate, and began to treat more scrap metals and residues rich in copper and precious metal content.Corresponding with the ever-changing pattern of feed sources, the Home smelter has adopted technological improvements to meet new and challenging business conditions. The technology of the original smelter of 1927has been completely replaced over the years in the quest for improvement. One of these major changes occurred in 1973 with the start-up of the Noranda Process Reactor. This extremely efficient smelting system has been exploited to treat a wide variety of copper and precious metal (PM) containing custom materials. This paper reviews recent developments and improvements achieved at the Home smelter, in the receiving, sampling and treatments of copper and PM scrap and secondaries, with particular emphasis on the development of new technology and equipment in complex feed materials treatment."

Jan 1, 1991

By Ahmad Ghahremaninezhad, Noelene Ahern, Yeonuk Choi

Arsenic (As) is a toxic element and is a major contaminant in the extraction processes of some metals (e.g. gold and copper). Due to the toxicity of arsenic species, its removal from As-containing streams from extractive metallurgy processes and safe disposal is absolutely necessary. For nearly complete removal of waste arsenic species from metallurgical process streams, it is required to have arsenic in its pentavalent state (As5+ species). This study presents an oxidation process for arsenic species with air or oxygen gas as oxidant. Activated carbon (AC) or other carbon based materials are used to catalyse the oxidation reaction. Air or oxygen gas is the only consumed reagent which makes the economy of the process very attractive. The oxidation reaction can be carried out at ambient conditions (room temperature and atmospheric pressure) in less than 24 hours.

Jan 1, 2014