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By S. A. G. Poppen, J. Konopka

"Petro-Canada's project investigative and experimental underground work in the Galt coal seam at Kipp, Alberta included the construction of an emergency egress and ventilation raise from surface.The Galt coal seam is 206 m below the surface and covered by 8 m of shale, sandstone and clay beds of the Oldman Formation, 128 m of shale, bentonite beds and sandstone of the Bearpaw Formation, and 70 m of glacial till and basal gravel. Free water was encountered from sand lenses in the glacial till and the basal gravel.Excavation for the ventilation raise was a nominal 2 m diameter and it was lined with a welded, continuous, steel liner of 1.2 m 1.D.Excavation in the glacial till was carried out with a surface bucket drill rig combined with hand mining. Ground support in the glacial till consisted of liner plates and backfill grout. The Bearpaw and Oldman formations were excavated by employing standard raise boring techniques. The individual liner sections of the continuous steel liner were assembled on surface and the entire liner column was lowered into the raise by employing hydraulic lift climbers. The liner column was back-filled with concrete.IntroductionThe Lethbridge Coal Field comprises an area of approximately 1 165 square km in the vicinity of Lethbridge in southern Alberta. Pacific Petroleums Ltd. proposed in a Preliminary Disclosure in January 1979 ""to open an experimental mine prior to development of a producing underground mine with an initial rate of 540,000 tonnes per year"". A 2 900-hectare group of leases in the Kipp-Coalhurst area was selected as the primary target for the Kipp experimental mine. The scope of work for the experimental mine included the construction of an access shaft with production capabilities, the construction of a ventilation and emergency exit raise, drive-ages in coal to yield a bulk sample, gathering of geotechnical information and the testing of experimental mining methods."

Jan 1, 1983

By Jr. Carmichael

"THE MAYO AREA was prospected as early as 1887. The first major activity started in 1898, when the Stewart River and its tributaries were examined for placer deposits, and in succeeding years the district became a small producer of placer gold. The first discovery of the lead-zinc-silver mineralization which has become the main interest of the district occurred in 1906, when a vein was found in the canyon of Galena Creek on the northwest slope of Galena Hill. This deposit was later known as the Silver King mine. In 1919 further discoveries were made on Keno Hill, approximately 15 miles east of the Silver King, the most important being the No.9 vein. Directly or indirectly, these finds are attributable to the search for placer gold, as galena was frequently found in the stream gravels.The 1919 Keno Hill discoveries were acquired by Yukon Gold Co. and operated through a subsidiary, Keno Hill Ltd., from 1920 to 1923. Most of the production came from No.9 vein. In 1921 Treadwell Yukon Corporation entered the field and acquired the Ladue mine. This company continued to operate for 21 years. It acquired in succession the Ladue, Sadie, Friendship, Lucky Queen, Elsa, Silver King, and Calumet mines. Its record of successful operations is very largely the achievement of the late Livingston Wernecke. Under his direction, the Treadwell Yukon Corp. produced metals with a gross value in excess of $21,000,000, in the face of greater transportation problems than exist today and with considerably lower metal prices.Treadwell Yukon ceased operations in 1942. Its entire assets were acquired in 1946 by United Keno Hill Mines Ltd., which has substantially increased the original holdings. It has drawn the bulk of its production from the Hector mine, adjacent to the Calumet. The Hector was not developed by Treadwell Yukon because of legal disputes among the vendors. It has proven to be the largest deposit yet discovered in the district."

Jan 1, 1949

By Jef M. van der Zel

The idea of veneering rich yellow gold alloys with a low-melting, high expansion porcelain, has been a driving force for metal-ceramic research in dentistry. Since 1990, with the advent of the Carrara System (1), a low firing temperature veneering ceramic allowed the use of gold alloys with a lower content of platinum and palladium than the traditional gold-platinum ceramic alloys and thus a richer yellow color. The earlier high gold-platinum ceramic alloys contained at least 12 percent platinum group metals to allow for dimensional stability when firing the relatively high melting traditional ceramics. This amount of platinum group metals gave the alloys a greyish tinge which made them unattractively steel colored and difficult to present as ?high gold alloys?. In the 90?s the new generation universal low-melting, high expansion gold alloys gained market share at a steady rate, starting in Germany, and have now for a great part replaced the traditional gold-platinum alloys (Fig. 1). The first alloys contained 75 wt-% gold and up to 9 wt-% platinum or palladium. They provided a metal-ceramic system in which a gold alloy having an aesthetic yellow colour is fired on with a dental porcelain tailored thereto. The tailoring is meant in respect of compatible coefficients of thermal expansion, and compatible melting or softening points of metal and porcelain. The major concerns in the beginning were with thermal stability during firing, the thermal expansion coefficient of the alloy against the porcelain (compatibility) and the yellow color. In a later stage, alloys with gold contents in the range of 50-60 wt-% gold were developed in analogy with the pale yellow gold-reduced alloys that were formerly used for crown & bridge work and the white gold-reduced alloys used for metal veneering where gold was substituted in part by palladium.

Oct 1, 2003

By N. W. D. Davis

"As I have recently carried out some further research on the Navan lead-zinc deposit data while working in Michel David's research team, I should like to add a few comments on the paper- ""Universal Kriging for Ore-Reserve Estimation- Conceptual Background and Application to the Navan Deposit"", by M. Dagbert and M. David (CIM Bulletin, pp. 80-92, February 1976). The first comment is that since this research has been carried out, important new theoretical advances have been made which make for an easier application of geostatistics to the non-stationary case (see Matheron0l). This is the theory of intrinsic random functions of order k. With the aid of this theory, it has been possible to write computer programs which can carry out automatically universal kriging, although so far such applications have been largely confined to automatic contouring and not to mining problems. However, if approached with care there is no reason why these methods should not be applied to mining problems and, in this case, an automatic study has been done on this data."

Jan 1, 1976

By R. A. Triglavcanin

Delivering dilution water and mixing this water with incoming feed slurry, addition of flocculant, maximising flocculant-slurry interaction to build aggregate size, unabsorbed flocculant percentage, volume average of solids volume fraction, momentum dissipation ratio, dilution recycle ratio, volume average shear, maximum shear rate at exit, aggregate size on exit, uniform discharge profile and more ? all of these need to occur in the right order and in the right proportions within the thickener feedwell, the secret to thickener performance.

May 1, 2009

By P. Tolvanen, A. Jalili

"When hard times strike in the mining cycle, sites tighten their belts and focus on lowering their unit costs. Lower unit costs can be achieved by reducing expenditure, increasing production, or by a combination of both. Faced with these requirements, site personnel must turn to areas where they can focus their effort for maximum return. For many sites, both in Canada and overseas, focusing on improving flotation cell maintenance is one of the areas where gains can be made for minimum outlay. Due to resource limitations and/or lack of equipment understanding, maintenance on many sites is only conducted on a reactive basis, once equipment fails. This paper will promote the idea that mineral processors should become more familiar with their equipment so they can ensure that the plant’s ability to produce is not compromised. By better understanding the flotation equipment and ensuring the critical components are maintained, it should be possible to unlock value in an operation. Flotation equipment inspections will be discussed in detail, including key items to look for during these inspections. Potential approaches for predicting wear and change-out time for flotation equipment components will be also demonstrated. An example of one approach used at a South African nickel site will be given.INTRODUCTIONWith metal prices decreasing and operating costs rising, concentrator operators are looking for ways to improve their bottom line. Lower unit costs can be achieved by reducing expenditure, increasing production, or by a combination of both. To meet the expectation of shareholders, mineral processors must turn to areas where they can get the best return for their efforts. One area where there is a large opportunity for improvement is in the maintenance of flotation equipment.On many mine sites, both domestically and around the world, it is quite common to see the philosophy applied of repairing equipment only once it has failed. Though some sites have advanced enterprise management systems and monitoring programs, in the authors’ experience, the decision on flotation equipment maintenance is rarely made on a proactive basis. Two common trends that are evident in the mining industry are that operations are under pressure to keep the plant producing, and maintenance managers generally have very strict budget targets to meet. In addition to these factors, few sites have a good understanding of the financial implications of running with worn or broken flotation equipment. Knights, Jullian and Jofre (2006) summarize this situation well, stating that the lack of correlation between some commonly used maintenance performance measures and key business drivers can lead to maintenance being seen only as a cost center (that needs to be reduced) rather than a tool for productivity improvement."

Jan 1, 2015

"9.1. IntroductionThe application of the electron microprobe for in-situ analysis of platinum-group minerals (PGM), first reported by Borovskii et at. (1959) and Genkin (1959), has resulted in a large and growing number of analyses of unidentified PGM. Figure 9.1 charts the increase in the number of reported unnamed PGM from 3 in 1959 to a total of 140 by 1979. All these minerals, with the exception of UN1968-5 and UN1976-1, were analyzed with the electron microprobe.There has been no recognised or consistent manner for reporting these unidentified PGM. The term ""unnamed"" has been used for PGM that are considered to be new species without a name as well as for PGM which have not been exhaustively compared to named and unnamed PGM in order to determine whether they are unique. Many of the so-called unnamed PGM are only unnamed because of poor microprobe analyses or because larger than usual elemental substitutions (e.g. Bi for As) made it difficult to calculate the true stoichiometry. Some of these unnamed minerals have been unnecessarily reported with non-stoichiometric formulae, as discussed by Cabri (1980). Better analytical data should reduce the number of such proposals.Another unfortunate practice, possibly used to by-pass the scrutiny of the Commission for New Minerals and Mineral Names, I.M.A., is to report a ""new"" mineral by referring to it by a name made up of its constituent elements. This has been deplored on a number of occasions (cf. discussion in Fleischer et at., 1976, p. 179), but some journals continue to publish such material. The Commission on New Minerals and Mineral Names has not recognised such ""names"" and these PGM are therefore included in this chapter with other unnamed minerals.A further example of inconsistency in reporting unnamed minerals is the report of a specific ideal stoichiometry with no further details (not even an analysis!); sometimes with a note that this will be reported in greater detail in due course. I have also been guilty of similar optimistic statements and, unfortunately, it is not always possible to follow through. Some authors give data on unnamed minerals in such a discrete manner that their reports are sometimes missed in literature searches."

Jan 1, 1979

By K. Aziz

The solutions to unsteady-state gas flow in a radial system have been reviewed in order to aid in the interpretation of drawdown data. It has been the practice to evaluate the time and rate conversion constants, directly or indirectly, by using reservoir data. This paper presents a method of determining these constants from drawdown data. A simplified approach to the de-termination for the various boundary conditions is presented. An example of a problem which illustrates the use of this theory appears in the appendix. UNSTEADY-STATE FLOW EQUATION The solution of any unsteady-state flow problem involves (1) the continuity equation, (2) the equation of state of the fluid, (3) the equation of fluid motion and (4) the boundary conditions. For the Darcy flow of a gas in the horizontal radial plane, the equation is when the viscosity, compressibility and permeability to gas flow may be assumed constant and the medium

Jan 1, 1963

By H. R. Bullis

"A 2003 paper discussed the idea that as gold mining companies grow larger it becomes more difficult for them to discover or acquire new gold deposits large enough to replace extracted reserves on an annual basis. Deposits of the size required to replace annual production of very large gold producers (VLGPs) are statistically few. An update in 2005 reviewed VLGPs with respect to production, reserves, and reserve life and observed recent changes in the gold mining industry. Now, more than 12 years later, this paper explores how those VLGPs have fared and how the gold mining industry has changed. KEYWORDS Gold, Gold price, Production, Reserves, Very large gold producer (VLGP) RÉSUMÉ Un article de 2003 examinait le concept selon lequel, à mesure que les sociétés d’exploitation aurifère se développent, il leur devient de plus en plus difficile de découvrir ou d’acquérir de nouveaux gisements aurifères suffisamment grands pour remplacer les réserves qu’elles extraient annuellement. Statistiquement, il existe très peu de gisements de la taille requise pour remplacer la production annuelle des très gros producteurs d’or. Une mise à jour de l’article en 2005 se penchait sur la production, les réserves et la durée de vie des réserves des très gros producteurs d’or ; elle portait sur les récents chan¬gements au sein de l’industrie de l’exploitation aurifère. Aujourd’hui, plus de 12 années plus tard, cet article explore l’évolution et les résultats de ces très gros producteurs d’or, ainsi que les changements qu’a connu l’industrie de l’exploitation aurifère. MOTS CLÉS or, prix de l’or, production, réserves, très gros producteurs d’orINTRODUCTION In 2005, the world’s top five gold producing companies were Barrick (after purchasing Placer Dome; 9.1 million ounces; Barrick Gold Corporation, 2005; Placer Dome, 2005), Newmont (8.2 million ounces; Newmont Mining Corporation, 2005), AngloGold Ashanti (6.2 million ounces; AngloGold Ashanti Limited, 2005), Gold Fields (4.2 million ounces; Gold Fields Limited, 2005), and Harmony Gold (3.0 million ounces; Harmony Gold Mining Company Limited, 2005). During the years leading up to that point, there had been a flurry of activity in the gold sector directed at consolidating production and reserves to create very large gold producers (VLGPs). As defined in Bullis (2005), a VLGP is a mining company whose primary busi¬ness is gold production and that has annual gold production more than 5 million ounces. A stated corporate goal of several of the VLGPs at the time was to become the largest gold producing company in the world."

Jan 1, 2019

By Robert B. Parsons

"Ontario and Quebec taxpayers will have to dig deeper into their pockets to pay more tax, according to budget papers tabled in these provinces in May 1993. Individuals will be hardest hit, but corporations will also have to ante up in the face of higher rates, reduced deductions, and new taxes.Up, up, and away...Somewhere in the bleak picture of the 1993 Quebec and Ontario budgets, there is a bit of good news for the mining industry.Careful scrutiny reveals:• Ontario will correct a capital tax provision which inadvertently penalizes flow through share issuers;• Quebec's flow-through incentives will be extended to December 31, 1995; and • both Quebec and Ontario will allow deductions for mine site reclamation payments.The industry may also find some comfort in the fact that Ontario's new corporate minimum tax will be profit-based (unlike the federal minimum tax), so that non-producers should not face a liability for this tax. There is some concern though, about Quebec's announcement that the refundable credit mechanism in the Mining Duties Act will be reviewed."

Jan 1, 1993

By Janice Zinck, Maziar E. Sauber

"To counter the recent uncertainty in the rare earths market, diversify the supply source, and help meet the future demand in this sector Canada initiated development of several new rare earth deposits. In the past few years, a number of various studies on rare earths plant design have taken place mainly covering process development, process selection, and flowsheet design. The purpose of this paper is to provide an overview of known domestic and potential resources and reserves of rare earths and their status quo with a focus on the metallurgical processes using the information available in the public domain. Plant designs currently under consideration in Canada are reviewed and evaluated. An outline of the areas of opportunity for selective innovation and technology development in the rare earths flowsheet development and the associated risks and rewards is provided.INTRODUCTIONThe rare earth elements (REE) have a very small annual market, but they are categorized as very strategic metals vital to global economic growth due to their indispensability to the development of modern defence system, green technologies and electronic applications. The International Union of Applied and Pure Chemistry (IUPAC) defines the REE as the 15 elements on the lanthanide series on periodic table of elements, plus yttrium and scandium. REE are classified as light rare earth elements (LREE; La to Gd), and heavy rare earth elements (HREE; Tb to Lu). Physical properties and chemical reactivity of yttrium is similar to those of HREE, thus it is categorized as such. Properties of scandium are not similar enough to classify it as either a LREE or HREE (Weng et al., 2015; Sappin & Beaudoin, 2015). However, the mining industry does not always abide to this definitive classification of the split between LREE and HREE. Therefore, in a comparative study of projects, there is a need to pay attention to how the elements are classified."

Jan 1, 2016

By C. Cornejo, C. Schuffeneger, J. Rosas

"At the end of 2010 the AMSA Esperanza Concentrator started commissioning. Located in the Atacama Desert this project is the first of several large size concentrators developed recently to operate in Northern Chile. In addition to the new operations to be implemented in the short term, many existing installations are planning expansions. The use of large size equipment is one of the common characteristics of the new concentrators, but also new technologies are being considered and innovation is present in most cases. Sea water or desalinated water will be required to process large tonnages of sulphide copper ores as well as gold bearing ores, since process water supply from the Andes will no longer be available. The high cost of sea water or desalinated water supply and the high cost of energy are not a limitation as the current metal market scenario allows obtaining an attractive NPV even from installations designed to process relatively low grade ores. A review of the current concentrators being developed in Chile is presented, including a description of the main design issues related to technology and innovation. An analysis of the Chilean mining industry is also presented, detailing mine and plant capacities as well as expected final products.INTRODUCTION The mining sector in Chile has become a reference when analysing the large concentrator plants projected or currently in operation all over the world. At present and as a consequence of the high price of metal commodities, most South American countries have an active mining sector. Chile is known as a major producer of metals. First records of copper production exported to Spain are dated to the early XVII century. Since then Chile has produced over 13% of the total copper ever produced in the world. After 1990 Chilean mining and the associated cluster of activities has substantially grown to levels never reached before, especially in the production of copper, gold and other non-metallic minerals. This dramatic increase is the result of an economic policy based on delivering comparative advantages and incentives for the admission of foreign capital to offset the weak domestic investment in previous decades. Massive mining of its huge mineral resources has allowed Chile to be a world leader in the production of copper and other base metals and mineral products."

Jan 1, 2012

By Andrea M. Ouchi

A major focus of ground control research presently being conducted by the Geomechanics Group in the University of British Columbia Mining Engineering Department is to incorporate weak rock masses (RMR76 less than 50) into existing empirical design relationships. An emphasis is being placed upon the updated span design curve/critical span graph originally developed at UBC. The original database has been augmented by mapping of one mine in Montana and of several mines within the Carlin and Getchell Trends of Nevada. In addition, a neural network analysis has been performed and modifications of the span design curves at the lower RMR76 range have been made. The common factor in all the above mentioned mines is a weak back and/or walls. In most cases, the ore zone is the weakest rock unit and must be dealt with to safely extract the mineral bearing rock. This work attempts to provide rock mechanic tools that will enable a mine operator to make economic decisions that will also ensure a safe working environment.

May 1, 2004

By J. Chenier, M. Boissoneault, D. Ducharme, R. Schonewille

The operation of Falconbridge's Sudbury nickel smelter has undergone significant change since the production was consolidated to a single electric furnace in 1994. In the late 1990's a capital program of about $100 MM (Cdn) was undertaken to expand and modernize the smelter. This project, known as Smelter 2000, was mainly driven by the need to process the new concentrate produced at Falconbridge's Raglan operation in northern Quebec. Included in the scope of the project was the installation of dry concentrate handling facilities, modifications to the roaster feed preparation system, installation of a matte granulation system and modification of one of the converters. Improvements to in-plant hygiene were also an important part of the Smelter 2000 project. Over the past 5 years much has been learned about the challenges in treating two significantly different concentrates. More recently, the introduction of a third concentrate from Falconbridge's new Montcalm operation near Timmins, Ontario has added another dimension to the operation. This paper will describe how the main challenges from the past 7 years have been overcome and discuss the path forward for the Sudbury Smelter Business Unit.

Jan 1, 2005

By Alex Cormode, Carlos Perucca

"Sylvinite ore from the Saskatoon area typically contains about 5% insolubles, occurring as clays and carbonates. These insoluble slimes must be removed sufficiently well to permit an efficient subsequent potassium chloride flotation, due to their high adsorptive capacity for amines used as potash collectors. The insolubles are liberated from sylvinite by high attrition scrubbing in a slurry. The liberated slimes are separated by multistage cycloning or by a selective flocculation-flotation process.An outline of the potash processing operations at Agrium Vanscoy Potash Operations is given, emphasizing the insoluble slimes froth flotation separation process. This process was originally implemented at the Agrium plant in the mid- 1970's and replaced a hydrocyclone system.IntroductionAgrium Vanscoy Potash Operations is located 40 Km southwest of Saskatoon, almost midway between the communities of Vanscoy and Delisle. Processing operations started in 1969, and the annual production capability was subsequently increased to the current 1.8 MM tonnes per year of muriate of potash.The mining operation at Agrium Potash which was described in a paper by Jones and Pruggerl , is done underground using four large continuous double rotor boring machines for the main production with development done by heliminers. Annual ore production is 5.5 MM tonnedannum. Ore is hoisted 1,100 m to surface for processing."

Jan 1, 1999

By H. Q. Fan

Construction equipment is an important type of resources of heavy construction contractors. Since equipment breakdowns can cause project delays and significant financial losses, the contractors are eager to know those factors causing equipment failures directly or indirectly, related to equipment design, maintenance, and operations. Although Bayesian network can be used for diagnostic analysis of failure events or making predictive analysis, building a Bayesian network for such purpose can be difficult as the cause-effect relations can be subjective and their conditional probabilities change with a wide variety of causal factors. A hybrid approach is proposed in this paper to update the Bayesian diagnostic network structures and parameters using real life data, the conditional probabilities and cause-effect relationships can be dynamically updated with observed failure records to reflect the real life situations of a complex equipment system. A case study is conducted to show the benefits of the hybrid approach in construction equipment diagnostic analysis.

Aug 1, 2013

By Dale Dean, Bill Hancock, Raul Mondragon, Carlos Aguilar, Chris Martin

"In 1942, commercial mining operations began in what is now the Lucky Friday Ag/Pb/Zn mine in Idaho’s Silver Valley. Wholly owned since 1962 by Hecla Mining Company, the mine has produced more than 145 million ounces of silver and has been a mainstay producer in Idaho’s Silver Valley for over 70 years.However, by the early 21st century, the mill had fallen, technologically, seriously behind the rest of the industry. Accordingly, starting in 2005, the current mill management team set to revitalizing the milling operation. This paper will describe how the mill was systematically evaluated and the aging infrastructure replaced with more current technology. Driven by internal mill review studies supported by QEMSCAN mineralogical balancing, the mill has in recent years been through waves of upgrading – from the installation of new mechanical and column flotation equipment to the introduction of on-stream analysis, a technology well-accepted around most of the industry but alien to this technologically conservative mining district.The experience at Lucky Friday is a testament to the need for ongoing structured mill optimisation and technology upgrading in established mining operations. This paper will describe engineering experiences associated with upgrading equipment in an operating mill, contained in a confined building. Experiences in teaching the team new ways of operating a mill, and finally the metallurgical rewards that have been reaped will be described.INTRODUCTIONMining in Idaho’s Silver ValleyIdaho’s Silver Valley is a 64-km long valley flanked by the US Northern Rocky mountains, seldom more the 3-km wide, and stretching across much of Idaho’s northern panhandle, roughly 150 km south of the Canadian border. Mining has been continuously active in the area for more than 140 years, during which time, the Silver Valley has become one of the richest silver producing districts in the world, and as of 1985 had out-produced the 500 years of production from the famed Potosi district in Bolivia. Since 1885, almost 100 deposits have been discovered and worked in the district (Chapman, 2000)."

Jan 1, 2011

By A. Suzue, T. H. Okabe, Y. Taninouchi

Methods for the physical separation and enrichment of platinum group metals (PGMs) from autocatalyst scrap were studied in order to develop an environmentally friendly and efficient recycling process. In general, an autocatalyst has a honeycomb-structured ceramic substrate that is coated with a catalyst layer containing platinum (Pt), palladium (Pd), and rhodium (Rh). Therefore, physical separation of the PGM-containing catalyst layer directly from the ceramic substrate is favorable for upgrading the autocatalyst scrap. In this paper, the authors present a scrap-upgrade process consisting of electroless iron plating and magnetic separation techniques. Iron was plated on the surface of a catalyst sample used to represent an autocatalyst, which was then crushed and magnetically separated. The Pd in the catalyst sample was successfully extracted and concentrated in the magnetic powder. Under certain conditions, the process increased the Pd concentration by a factor of 4 and recovered 89% of the Pd in the autocatalyst sample.

Jan 1, 2014

By K Byrne, W. Hawker

The average grade of copper concentrate is steadily declining, forcing the industry to turn to lower grade and metallurgically challenging orebodies. When faced with a low grade, challenging ore, mining companies are often forced to choose between high recovery at low grade or low recovery at high grade. Hydrometallurgical processing of copper concentrates using metathesis reactions, which replace iron with copper in copper-iron sulphide minerals and increase the copper to sulphur ratio in copper sulphide minerals, provide an opportunity to upgrade copper concentrates and potentially allow high copper recovery for a high grade concentrate. Factors such as concentrate mineralogy, reaction time and temperature, and the concentrations of copper, chloride and acid in solution are reported to affect the reaction extent and mineral phases formed by metathesis. In this paper, a copper concentrate has been studied over a wide range of conditions to investigate the influence of these key parameters on the extent of copper metathesis reactions and product phases formed. Solution and solid phases are assayed with the main mineral phases identified by Quantitative X-Ray Diffraction. INTRODUCTION The minerals present in copper deposits determine the prospective processing options either: pyrometallurgical or hydrometallurgical. For copper oxide ores, copper is typically present as oxides, carbonate, chlorides, silicates and sulphates. These minerals are readily solubilised in acid and are usually treated through hydrometallurgical processes. The typical process route for copper oxides is to leach copper into aqueous solution, purify and upgrade the solution phase through solvent extraction and then recover copper as metal by electrowinning (Davenport, King, Schlesinger, & Biswas, 2002). Copper sulphide deposits may contain a multitude of copper bearing minerals, including chalcopyrite, bornite, enargite, covellite, digenite and chalcocite. The copper ore grade and treatment options are affected by the mineral type and distribution. Sulphide ores are typically treated through comminution and mineral flotation to form concentrates, followed by pyrometallurgical smelting. Hydrometallurgy can also be used to process sulphides depending on the mineralogy and impurity levels (Davenport et al., 2002). The trend of decreasing copper grade with increasing impurity levels are common across the mining industry and pose future challenges to copper processing. This trend has prompted research into hydrometallurgical options for upgrading copper concentrates. One promising hydrometallurgical option is using metathesis reactions. Metathesis reactions, sometimes also called double replacement or displacement reactions, are chemical processes involving the exchange of bonds between two chemical compounds or species. In this case, the metathesis reactions involve copper in solution exchanging with cations in the solid sulphide concentrate. The driving force for copper sulphide metathesis is the relative affinity of the exchanging cation elements for sulphide. Based on sulphide precipitation diagrams, the expected order of affinity for sulphide should be Hg2+ > Ag+ > Cu+ > Cu2+ > Bi3+ > Cd2+ > Pb2+ > Sn2+ > Zn2+ > Co2+ > Ni2+ > Fe2+ > Mn2+ (Monhemius, 1977). Hence, copper metathesis reactions are capable of increasing copper content and removing impurities such as iron, nickel, zinc and lead from copper concentrates.

Jan 1, 2019

By C. O. Staples, J. G. Morrow

The application of cationic flotation to the upgrading of magnetic concentrates was investigated in the laboratory by both batch and continuous test procedures. It was found that the collection of coarse gangue particles with amine, heretofore considered a serious obstacle to this particular application of cationic flotation, is greatly enhanced by a drastic reduction in what might otherwise be considered normal impeller speed. Gangue flotation is in-dependent of variations in the rate of aeration. The collector and Crother additions and the impeller speed which favour the formation of a matte froth yield optimum results.

Jan 1, 1966