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By J. E. Nesset, E. R. Bobicki, K. L. Bilaniuk

The introduction of froth flotation technology in Canada, and in particular, in British Columbia, began not long after it was successfully applied in the Broken Hill mining area of Australia which began around 1905. It proved to be a revolutionary and transformative technology that resulted in marginal operations in copper, lead and zinc becoming profitable in spectacular fashion. The paper presents the technology of both oil flotation and froth flotation in the context of the challenges of the time and its early application in British Columbia at the Le Roi No.2 mine (1903), the Britannia Copper mine (1912), and at the Allenby concentrator of the Copper Mountain mine (1918-19). New-found archival documents indicate the Britannia application to be the first production application of froth flotation for copper ore outside Australia, a claim that is currently made by the Braden mine (now El Teniente) in Chile. Flotation was initially an add-on process following gravity methods but was rapidly shown to be far superior method for the bulk and selective recovery of metal sulphides. Flotation proved particularly successful for the recovery of zinc sulphide (the so-called ‘zinc problem’) which was considered a contaminant at the time. The ‘copper problem’ related to the poor recovery of fine copper sulphide particles that were not amenable to gravity methods. The success of flotation led to changes in both the scale and methods of mining, concentration and smelting in a manner that allowed integrated mining companies to flourish. Many are still with us today. INTRODUCTION The advent of froth flotation in the early 20th century was truly a revolutionary technological development, not only for the mining and metallurgical industries, but arguably more so for business and society overall. The Canadian technology historian Jeremy Mouat stated (1996) “The development of flotation was the greatest single metallurgical improvement of the modern era...it is not overstating the case to claim that flotation was of central importance to the smooth functioning of the global economy”. It should, therefore, be a story of interest to us all. The aim of this paper is not to retell the full story, that has been well covered by others (Hoover, 1912; Rickard, 1916a; Hines & Vincent, 1961; Lynch et al., 2010) but rather to add some Canadian perspective and the key role played by companies and individuals in those early days, focusing on events in British Columbia’s copper industry. EARLY DEVELOPMENTS During the later half of the 19th century, a number of flotation-related patents were issued. These include the 1860 patent (Britain) granted to William Haynes for a process to separate sulphides from ground ore by mixing it with oil (1-10% wt) followed by a separation process in a water-filled vessel; the 1877 patent granted to Georg and Adolph Bessel (Germany) for a process involving the mixing of oil and graphite ore followed by boiling in water to produce a high grade graphite froth (>90% carbon); and the 1885 patent granted to Rebecca ‘Carrie’ Everson for the separation of sulphides by mixing sulphide ore with small quantities of oil, and adding water followed by sulphuric acid. These processes are more properly referred to as bulk oil flotation due to the relatively large quantity of hydrocarbon used.

Jan 1, 2019

By W. G. Hubler

History The Aldermac mine is situated on the Nipissing Central railway near the ' centre of the township of Boischatel, Quebec, and is about ten miles west of Noranda. Aldermac Mines, Limited, is a subsidiary company of Towagamac Exploration Company. The property was staked by Messrs. Alderson and MacKay and McMartin, during the winter of 1922-23. During October, 1925, a copper discovery was made by K. W. Fritzsche, who was in charge of exploration work at that time, the first trench on this discovery averaging 8 per cent copper over a width of ten feet. This led to the discovery of another body 200 feet to the north, with an average of 3 per cent copper over fifteen feet in width. A magnetic survey was then carried out which led to the location of the large pyrite ore-bodies which have been developed in the past few years. Development work was carried on to a depth of 1,125 feet, and approximately three million tons of massive pyrite ore was indicated. Extensive metallurgical tests were conducted in the laboratories of the Mines Branch of the Department of Mines at Ottawa to determine the proper metallurgical treatment and the economic possibilities of the ore. Owing to the comparatively low copper content, and the uncertainty of the copper market, it was doubtful if the mine could be profitably operated for the production of copper alone. Messrs. Alderson & MacKay, however, realized the possibility of utilizing the large tonnage of pyrite as a substitute for native sulphur, 'which in past years has been imported into .Canada for the manufacture of acid and sulphate pulp in paper mills. They therefore organized the Sulphite Research Corporation with the object of developing an economical process of utilizing the pyrite.

Jan 1, 1932

By R. Lovat, J. A. Hunter

"The design, development, and verification of the Lovat 7.6metre diameter full-face tunnel-boring machine is reviewed. Programmatic and technical challenges are outlined with a review of the specifications and the design to meet these requirements. Subsystem designs are presented for the waste material removal, ventilation, cutter head, structural support, advance technique, water removal, and interfaces with the Donkin-Morien Mine. The techniques used to verify that the design meets the requirements is by testing in the Lovat factory and in the field. Certification of the machine for use in a methane environment is discussed.IntroductionStudies have concluded that the average annual worldwide tunnel construction is 500 kilometres at an estimated average co st of $3,400 U.S . per linear metre. The total market value of the tunnelling industry is estimated as approximately $1.7 billion U.S. per annum. Of this, the current market for tunnelboring machine excavation is approximately $270 million U.S. per annum worldwide with a further potential of $250 million if more contractors are convinced that Tunnel-Boring Machines (TBM) are more suitable than conventional techniques. The worldwide civil tunnelling market has the potential to double each year in the next 5 to 15 years. Growth has been identified in the energy and mineral resources sectors of the economies of many nations and a significant volume of machine tunnelling studies and trials are presently underway for the extraction of coal, uranium , heavy oil or oil sand fuels, metallic and non-metallic industrial minerals and base metal or rare earth ores. Further tunnel projects for regional transportation, waterpower, irrigation , high density urban transportation, storm water sewers and water supply purposes are continually being implemented with new concepts like military security facilities and underground storage schemes being considered.Lo vat Tunnel Equipment of Rexdale, Ontario, the only Canadian manufacturer of TBMs was incorporated in 1973 to manufacture so ft ground tunnel-boring machines to satisfy this growing market demand. Lovat has produced an average of 5 machines per annum during the period 1972 - 1982 and has established an international reputation for competitive costs, quality of construction, after-sales service, and reliability. As of June 1982 Lovat TBM's have been used to tunnel over 240 km in projects throughout the world."

Jan 1, 1984

By W. W. Cummings

Canada's only current tungsten producer started up in 1962 with a small open-pit mine on the Flat River , 180 air miles north of Watson Lake, Yukon Territory. The orebody was in a contact-metamorphic skarn zone and contained about 1.5 million tons of ore grading an estimated 2.47% W03 and 0.5% copper. Near the end of the open pit , a new zone was discovered on the lower limb of the same structure, and the decision to go underground was made in 1972. The new "E Zone" contains over 4 million tons of ore grading an estimated 1.6% W03 and 0.28% Cu , and has been supplying the concentrator at about 175,0 00 tons/ year since late 1974. A continuing program of change and up-grading is necessary in the conversion from a seasonal open-pit mine with limited life to an underground operation with twenty years of reserves. Changes are necessary in plant and services as well as the mine. Also, environmental protection requirements have changed from rudimentary to rigorous over the life of the operation. This paper sums up the changes in the operation since 1971 and outlines the changes yet to come.

Jan 1, 1977

By R A. Burwash

In the Yellowknife geologic province, 2,600-million-year-old granites are cut by three sets of diabase or gabbro dyke : (1) large dykes striking 70°E to E-W, (2) rare dykes striking N-S to 30°E and (3) an abundant swarm striking N 10°-300W. Preliminary potassium-argon dating has been carried out on whole-rock samples of the chilled margins and coarse centers of the dykes, and on mineral separates from the dykes and contact aureoles. Data from seventeen dated samples suggest that the dyke sets were intruded during three periods of basaltic magmatism -2,200, 1,500 and 1000 million years ago. The two earlier periods closely follow the time of emplacement of granites in the Yellowknife and Churchill geologic provinces. The latest diabase dykes occurring in the Yellowknife province are temporally related to a widespread basaltic magmatism, for which the term Keweenawan is not appropriate. D DRING the past ten years, methods of physical age determination have been widely applied to date the time of intrusion or metamorphism of Precambrian rock

Jan 1, 1963

By A. J. Stapleton

"This paper gives a brief description of the occurrence and development of the Needle Mountain mine at Gaspe Copper Mines, Limited and describes the trackless mining equipment used in this highly mechanized underground operation.Maintenance of the trackless equipment is considered in detail, with particular emphasis on scheduling and control, examination and inspection. All maintenance is carried out in an underground garage, and the facilities for maintenance and field repairs are also described. Maintenance costs are given for various units and the figures for different types of loading and haulage units are compared to support the trend toward larger units and the increasing use of rubber-tired loaders."

Jan 1, 1969

By W. E. Armstrong

Gypsum was first exploited as ?a commercial proposition in this province by the Union Mining Company which, in 1900 opened quarries on the east shore of Lake Manitoba, near the present site of Gypsumville. This company established a mill at the head of Portage Bay on the lake, and the manufactured plaster was carried by the companies boats to McArthur's siding on the Whitemouth river near Westbourne, Man., from which point it was distributed. In 1904 a reorganization took place and the Manitoba Gypsum Company Limited bought out the original company, and operated the original mill for about one year when it was destroyed by fire. There were many factors which rendered the operation of a mill at the quarries very difficult; lack of rail transportation for bringing in supplies, and the impossibility of local power development made manufacturing costs very high. Satisfactory distribution could not be affected because of water transportation and poor terminal facilities at McArthur's siding. For these reasons the new mill was built at Winnipeg, where cheaper power and better distributing facilities permitted the industry being placed in a better position. The company continued to bring the gypsum rock by steamer to Totogan, from which point it was transported by rail to Winnipeg. This period was one of steady expansion as the product became better known and more universally accepted as a wall finishing material. Unfortunately, in 1909, this new mill was destroyed by fire, causing a serious set-back to the company, at a time when the steady growth of the western market gave every promise of the industry being placed on a profitable basis.

Jan 1, 1925

By M. Kunst

The creep behavior of three AJ62 alloys was investigated in a wide range of stresses and temperatures. Multi-level tensile creep tests revealed a distinct primary creep stage and a high stress exponent up to a value of 10. The threshold stress concept which is commonly used in combination with high stress exponents was utilized in the analysis of creep behaviour. This resulted in an effective stress exponent for the AJ alloys indi¬cating dislocation climb as the dominating creep mechanism. In addition, microstructural observations of the lamellar eutectic and of the a-Mg-matrix were carried out using opti¬cal microscopy, SEM and TEM. The creep properties of the alloys are discussed in the context of microstructural parameters such as phase volume-fraction, stability and solute supersaturation.

Jan 1, 2006

By W. G. McBride

INTRODUCTION Preparation of this article, at the request of the Committee on papers, has been undertaken in the hope that it may stir up helpful discussion and constructive criticism. The Canadian mining industry is in the dumps and there is no use trying to deny the fact; nor does it help to say that other industries are in as bad or a worse condition. Let us face the situation honestly and see just how serious it is. The entire financial and industrial world is in a state of depression. The gravity of the case is no doubt exaggerated by contrast with the wave of optimism and false prosperity which pre-ceded it. The prevailing gloom and pessimism are just as irrational as was the former super-optimism. As far as we mining engineers are concerned, the causes are quite beyond our control, and it is the effect upon our own industry which interests us most. This effect is an accumulation of mineral products with consequent depression in price to a point where profits have almost, if not quite, disappeared. Whether this accumulation of stocks is the result of over-production or under-consumption is difficult to say, but it would seem likely that there is a combination of the two. The introduction of selective flotation has brought about a large increase in the production of zinc, a moderate increase in the production of lead, and a comparatively small increase in copper. It has turned relatively small mines into great producers, as in the case of the Sullivan, revived expiring mines like La Cananea, and brought-in new ones like Flin Flon

Jan 1, 1931

By L H. Warren

The types of equipment available for generating a plasma have been reviewed. The efficiency and potential of the plasma generating equipment used in performing extractive metallurgical reactions have been determined. A general classification of the reactions that might be per-formed in a plasma has been proposed. Experimental work done on extractive metallurgical plasma reactions, heat transfer between the plasma and solids, and the quench of the products of plasma reaction has been summarized. From the preliminary results it appears that the high-intensity are or the transpiration-cooled anode plasma torch offer the most promising areas for further research. C ONSIDERABLE world-wide research effort is currently being devoted to the development of processing technologies which employ the new high-temperature generating devices that have appeared over the past few years. The plasma flames produced by these devices offer the potential for subjecting materials to any single gas or mixture of gases at temperatures up to 20,000°K. With these conditions available, many reactions in extractive metallurgy,

Jan 1, 1965

By S. Mao

Total station has been predominantly applied in stationary survey scenarios in construction. With the moving target tracking and point survey automation functions, a robotic total station (RTS) lends itself well to more dynamic applications. Nevertheless, a RTS unit is still unable to track multiple targets simultaneously or to survey a target point when the line-of-sight is temporarily unavailable. In this paper, we propose a methodology to synchronize and automate multiple RTS units intended to address dynamic tracking and surveying applications in the construction field. By using the application programming interface (API) from the manufacturer, we implement the proposed methodology and the prototype system integrates two RTS units in regard to space and time and communicates survey command instructions among RTS units through wireless networks. The two RTS units can be operated to survey the two ends of one swinging sling concurrently in order to retrieve the actual length of the sling within several millimeters accuracy. Besides, in applications where line-of-sight between a target object and one RTS unit cannot be guaranteed all the time, continuous surveying can be materialized by automatically delegating the task to another synchronized RTS unit with clear view of the target object. A field test was conducted to demonstrate the application of the proposed automation approach in which sling length was measured of a rigging framework used for lifting industrial modules. The testing results are presented and achievable accuracy and reliability are discussed. The proposed solution overcomes the limitations of global positioning system (GPS) and laser scanning and holds high potential to provide cost effective solutions to many dynamic field applications.

Aug 1, 2013

By M. K. Gangal, M. A. Stoakes, A. E. Hall

"The major features of the CANMET thermodynamic mine ventilation network program, developed by the Mining and Mineral Process Engineering Department of the University of British Columbia for the Canada Centre for Mineral and Energy Technology (CANMET), are described.The program is designed for use by deep Canadian mines in planning ventilation flows where the effects of auto-compression of air, moisture lift work and natural ventilation are significant. Routines to simulate stalled fans and give an optional cost printout have been included in the program.A supplementary plotting program used to simplify data interpretation is also described.The program is described with a test data example of a deep mine. It is a valuable analytical tool which can assist ventilation engineers to simulate many alternative ventilation strategies at a low cost in a very short time.IntroductionCanadian underground mines are becoming deeper and more extensive. The use of more and larger diesel-powered equipment increases the amount of air required to be circulated in these complex systems. These effects, coupled with the increasing unit cost of the energy required for mine ventilation, require that the air is used with maximum efficiency.Optimum airflow distribution can be obtained by using network computer programs enabling engineers to plan future ventilation systems based on quantitative assessments. The programs used for deep mines must make allowance for the change of air density with depth, as the assumption of incompressible flow leads to serious errors. Natural ventilation effects may vary with depth and from part to part of the mine; this must be catered for by the program. The air moisture content changes throughout the circuit and a significant portion of the fan work may be used in removing moisture from the mine; as this work varies directly with the flow, a suitable relationship must be utilized in the program."

Jan 1, 1982

By K. Svens, M. Lahtinen, L. Lehtinen

"Outotec's direct leaching process is an atmospheric leaching process for sulphidiczinc concentrates. The direct leaching process, based on special leaching reactors developed by Outokumpu and leaching know-how, is the most economical way to produce electrolytic zinc. The newest industrial-scale application of Outotec's direct leaching process will be started up in 2008 in China at Zhuzhou smelter. The process isintegrated to the existing production plant, replacing part of the old production facilities by modern technology and increasing the production capacity significantly. The process equipment supplied by Outotec includes also tailor-made reactors designed on the basisof the work and experience of Outotec Research Centre."

Jan 1, 2008

By W. G. Hubler

It has been within only the last two or three years that enough progress has been made in preferential flotation to warrant metallurgists in recommending the installation of commercial-sized plants for the treatment of copper-zinc-iron ores. Until the new processes had been worked out successfully, the treatment of this type of ore had proved a stumbling block in the path of metallurgical progress. Separation of lead-zinc ore is comparatively simple. A lead-zinc ore low in iron may be separated and concentrated by gravity con-centration, provided it is not necessary to grind too fine. Owing to the specific gravity of chalcopyrite and sphalerite being so nearly the same, however, their separation by gravity concentration is out of the question. Complex lead-zinc-iron ores in which the several minerals are intimately associated, requiring fine grinding to free them, have been successfully treated by flotation for the past fifteen years. Galena is easily floated, and its flotation, unlike that of chal¬copyrite, is not affected by the reagents used to inhibit the flotation of sphalerite and iron sulphides. When an attempt was made to use the methods of lead-zinc se-paration on copper-zinc ores, it was found that the depressant re-agents added to inhibit the flotation of the iron and zinc minerals would, under certain conditions, depress a large part of the copper. It was also recognized that, in the grinding of copper-zinc ore, soluble salts were generated which were detrimental to flotation unless properly controlled. The main part of this paper will be a discussion of solutions in the grinding circuit in relation to the pro¬duction of soluble salts and their effect on flotation.

Jan 1, 1931

By Jose R. Hernandez-Aguilar

"This paper revisits data from previous studies (Hernandez-Aguilar, 2010, 2011) to better understand the link between metallurgical performance and bubble size (Db) in the collection (pulp) zone of full-scale flotation systems. To obtain conclusive evidence exclusively related to the collection zone, the experiments were designed in those studies to control both the bubble generation method and the influence of the froth zone on the overall metallurgical performance in industrial and pilot-scale flotation columns. The results showed that generating small (1 mm) bubbles had a significantly higher beneficial effect on the recovery of coarse (> 75 µm) particles compared to the effect on fine (< 16 µm) particles. It was observed that, under certain practical conditions, the recovery of liberated coarse particles was close to zero, but could be recovered almost completely by reducing bubble size. The evidence revealed an apparent inconsistency of the so-called “k–PSb” model: at constant froth recovery, increasing Sb did not always result in higher recovery, as the model predicts. Overall, the evidence showed that it was not the Sb but the bubble size that proved to be a more reliable link to metallurgical performance. Only under highly suboptimal bubble size conditions (Db = 3 mm) did the froth zone seem to play a role, possibly reflecting an effect of pulp-zone bubble size on froth stability. However, for the most part, both the bubble generation method and the froth zone played inconsequential roles. An empirical model that better describes the kinetics of particle collection is proposed.INTRODUCTIONStudies showing the link between metallurgical performance and the interactions of bubbles and particles in the collection (pulp) zone of industrial flotation systems are scarce. A common belief among a number of mineral processing practitioners considers that “small” bubbles are favourable to recover “small” particles and that, conversely, “larger” bubbles are more efficient at floating “coarse” particles. However, perceptions like this are often substantiated by anecdotal evidence rather than by rigorous data analysis. What is the optimum bubble size for a particular case, how operating conditions can be adjusted to control a target bubble size, and whether the bubble size needs to be changed in the first place to optimize the operation of a flotation plant are questions that usually remain without solid answers.The studies reported by Hernandez-Aguilar (2010, 2011) were, in part, performed to test the effect of bubble size on flotation response and, thus, help address some of the above questions. The focus of the studies was to optimize the metallurgical grade-recovery performance of the Cu-Mo separation plant at Teck’s Highland Valley Copper mine (HVC). The outcome was compelling and significantly valuable: consolidated production data showed that in 2008 – the year when the recommendations from the studies started to be implemented – the Mo plant recovery was 89%, and gradually increased to 92% and 94% in 2009 and 2010, respectively, along with an increase in Mo concentrate grade. (Note: these production figures were not included in the publications quoted above; however, they were shown during an oral presentation at the 43rd Annual Meeting of the Canadian Mineral Processors in 2011.)"

Jan 1, 2016

By William C. Martin

"Consolidated Sudbury Basin Mines Limited owns two mines, 4 miles apart, near the southwest end of Sudbury Basin. The Errington mine lies close to the north boundary of Creighton Township and about 18 miles by car from Sudbury. The Vermilion Lake mine is in Fairbank Township, on the south side of Vermilion Lake.The first discovery of base-metal mineralization within Sudbury basin was made by James Stobie in 1897 at Stobie Falls on the Vermilion River, half a mile west of the Errington mine. A few years later Alphonse Oilier made a discovery of massive pyrite with base-metal sulphides near the west end of the present Errington workings.No work of consequence was done on these discoveries until 1924, when Joseph Errington acquired options on a large acreage of ground which was later taken over by the Treadwell Yukon Company Limited. After considerable diamond drilling this company sank No. 1 shaft in 1926. In the next three years, a large amount of underground development was done, a pilot mill was constructed and operated for two years. All operations ceased in 1931 with the fall in metal prices. While in operation the pilot mill treated 186,172 tons of ore the average grade of which was 1·07 per cent copper; 1 10 per cent lead; 4·60 per cent zinc; 0·03 ounces gold; and 1 70 ounces silver.Up to the time of closing in 193 l there had been completed at the mine 26, 790 feet of lateral work and 75,500 feet of surface and underground diamond drilling. The company records, however, showed no figures on ore reserves, except broken ore in stopes amounting to about 60,000 tons. A study of the plans, prior to reopening the mine in 1952, showed 1,450 lineal feet of ore (at 1952 prices) opened up by drifting on the 300-foot and 500- foot levels. It is clear that no comprehensive picture of the structure was had at this time. The orebodies were considered to be very irregular pods scattered through masses of quartzite-carbonate in a sheared zone about 800 feet wide. In some way the ore was believed to be related to the tuff-slate contact zone. With this picture it was impossible to make a reasonable ore estimate or even gauge the tonnage potentialities with any feeling of reliability."

Jan 1, 1949

By H. D. Goodfellow, R. A. Elliott

"This paper covers the evolution of large mills and autogenous grinding and compares grinding practice in the iron ore industry with that in the base metal industries. Comments on novel methods of grinding are presented for discussion. Recent developments in the field of classification are briefly reviewed. A systems analysis approach to grinding circuits is discussed. Finally, a point is made for establishing a group within the industry with the purpose of developing a comprehensive evaluation of grinding research and development."

Jan 1, 1971

By C. Edwards

ABSTRACT The versatility and specificity of rare earth elements (REEs) have led to their use in an everincreasing variety of applications in new technologies; consequently, demand for REEs has increased significantly. However, separating REEs safely and effectively is a complex and expensive process. This paper presents a review of REE mineral processing technologies, providing an update on current capabilities in REE mineral processing and REE extraction from the major commercially valuable REEbearing minerals such as bastnaesite, monazite, and xenotime, as well as the ion-absorption type of REE deposits.

Jan 1, 2013

By John H. Walsh

"ForewordThis paper is to be published in two parts in succeeding issues of the CIM Bulletin. In Part I, the problem of global climate change is explored together with a summary of the government&apos;s present policy in this field. Implications for the steel industry are examined as are possible strategic responses. Part II of the paper will present a new possibility - the joint production of iron and liquid fuels useful for transportation purposes. In the joint production case, the objective is to use carbon for more than one purpose in what might be termed a &apos;carbon cascading&apos; technique. ABSTRACTIt is becoming increasingly probable that emissions of carbon dioxide from the fossil fuels will have to be reduced to deal with the threat of global warming. This issue is likely to be resolved one way or the other in the period 1995 to 2000 which does not leave much time to develop responsive options. In the intervening period, the policy of the Government of Canada is to stabilize emissions of greenhouse gases at their 1990 level by 2000, by encouraging greater efficiency in the use of energy. Should further reductions prove necessary, economic instruments would probably be employed but these would not be applied before a comprehensive international agreement is reached.There are three main themes in this paper: it is assumed that measures to control carbon dioxide emissions will in fact be necessary by the tum of the century; that there will be a rising need for liquid fuels to supply the world&apos;s steadily growing fleet of motor vehicles for many years to come, and that the future niche for Canada &apos;s industry in such a carbon-constrained world will be the operation of the energy-intensive industries with efficiency and environmental sensitivity.The steel industry, as a large user of both coal and energy in other forms, would be significantly affected by a need to reduce carbon dioxide emissions. This paper first examines what might be called the conventional responses open to the industry in such a situation and then explores a new possibility for making better use of carbon by the co-production of iron and liquid fuels."

Jan 1, 1992

By B. K. Gorain

"The Air-Metabisulfite (AMBS) process has been developed to treat complex copper, molybdenum and precious metals (gold, silver) bearing ores using brackish and sea water. This process was able to produce significantly better copper concentrate grades and higher recovery than possible using conventional lime and/or cyanide based processes for certain complex ores with high sulphide gangue minerals. The AMBS technology in now used commercially following a rigorous evaluation process emanating from laboratory curiosity to plant applications. In addition, many projects have embraced this technology at a feasibility level involving various complex ore bodies.This paper presents a summary of the findings from testing the AMBS technology on various ores types. Experiences gained from this successful development from bench to piloting and then to plant applications are also presented in this paper.INTRODUCTIONProcessing of sulphide copper, molybdenum and precious metal ores typically involves flotation of copper bearing minerals while depressing non-sulphide and other non-copper sulphide minerals such as pyrite, pyrrhotite and sometimes arsenopyrite. Though in many precious metal ores, the values are in these sulphide minerals as well. The conventional method employed in the industry to produce a saleable copper concentrate requires depression of these non-copper sulphide minerals using an alkaline pH above 9.5, though 10.5 to 11.5 is more common. Alkalinity is controlled by the addition of a pH modifier. Lime is normally employed as a pH modifier due to its relatively low cost; however, the costs associated with adding lime can be significant and the effectiveness of lime as a depressant could be drastically reduced when the process water supplied to the flotation circuit contains high level of dissolved salts. In some cases, a small amount of cyanide is used along with lime to depress non-copper sulphide minerals especially when its proportion to copper sulphide minerals in the ore is higher than three."

Jan 1, 2016