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By R. Dahlke, J. A. Finch

"A campaign was undertaken during the greater part of 2001 at Noranda’s Brunswick Mine Concentrator to investigate the role of gas (air) superficial rate distribution (Jg profile) to the cells in the final Zn cleaning stage (bank of seven cells). Three profiles were tested: Balanced (each cell with same Jg), Increasing (from cell 1 to 7), and Decreasing, along with an “as found” profile in a parallel control bank. The experimental design allowed for two confounding factors, changes in ore type and circulating load. The Increasing profile consistently gave the best metallurgy (down-the-bank grade / recovery). The reason for improved performance was traced to the response of the first few cells. The Increasing profile gave the highest selectivity of sphalerite against non-sulphide gangue (NSG) in these cells with relatively even recovery per cell down the bank (10-15% based on feed to each cell). The other profiles gave lower selectivity and higher zinc recovery in the first cells (up to 25% in cell 1), which combined to reduce overall bank performance. The increased selectivity with the Increasing profile is attributed to the low gas rate in the first cells reducing water recovery and hence limiting entrainment of NSG gangue. The Increasing profile was subsequently configured for all four stages in the zinc cleaner circuit.INTRODUCTIONThe performance of a flotation circuit is largely the result of the operator’s response to visual clues. This includes manipulation of the gas (air) input and how it is distributed to cells in a bank. A lack of sensors prescribes this approach. Over the past ten years the Mineral Processing Group at McGill University have developed a set of gas dispersion sensors including one to measure gas superficial rate (or simply “gas rate”), i.e., volumetric gas rate per unit cell crosssectional area, Jg (Gomez and Finch, 2002). The device collects bubbles in a tube immersed in the pulp and infers Jg from the pressure-time curve generated after a valve is closed and air starts to accumulate. The usual units are cm/s. It is robust, reliable and suited for plant use.A version of the Jg sensor was tested extensively during 2000 at Noranda’s Brunswick Mine Concentrator (Dahlke et al., 2001). The results were sufficiently encouraging that a sensor was fabricated to suit local requirements (Insta-Jg). The sensor detected malfunctioning field instruments and flotation mechanisms, and demonstrated that gas distribution to cells in a bank “as found” had no particular pattern, or profile. Preliminary testing suggested that a balanced profile (i.e., all cells with the same gas rate) gave superior metallurgy (grade / recovery down the bank) than the “as found” profile. This observation prompted a focused campaign to explore the impact of the gas rate (Jg) profile, introducing the notion of “gas distribution management”."

Jan 1, 2004

By Edgar A. Manker

"Today's market for columbium has only developed in the last two decades, and in this sense it is ""newer"" than molybdenum, vanadium and most other steel alloying elements. In this short period, it has assumed a very important role in steel alloying and in superalloys. From a few hundred thousand pounds of columbium in 1960, consumption has grown to nearly 30 million pounds per year, with a market value approaching two hundred million dollars.To assess the outlook for columbium, we will first consider the historical development of consumption and supply, particularly noting that all of today's major mines were developed during the last two decades. From current production, we will attempt to reasonably project the future. This future may well include new producers, particularly some producing columbium as a co-product with tantalum.The growth of current applications, and emerging new applications, will be considered with regard to future consumption and in relation to future trends in pricing.IntroductionThe nineteenth century was a busy time for the discovery and naming of new elements. Among those discovered were columbium in 1801 and niobium in 1844. Although it was later shown that columbium and niobium are the same element, the two names are still used today. Niobium has been pronounced the ""official"" name by the International Union of Pure and Applied Chemistry, but columbium is still widely used in commercial practice, and we have chosen to use columbium in this paper."

Jan 1, 1981

Taking Up the AFN Corporate Challenge ?? About MAC ?? ?Towards Sustainable Mining? ??Mining and Aboriginal Peoples Framework ?? AFN-MAC Relationship ?? A New MAC Northern Initiative ??Social and Economic Progress ?? A View to the Future?

May 1, 2009

By Claude Bazin

"Laboratory semi-batch flotation tests were conducted using two different sulphide ore samples. The size reduction was adjusted to cover a wide range of flotation feed size distributions. Results show that similar recoveries can be achieved independently of the fineness of grind. This result suggests that possible energy savings could be achieved by a redistribution of the power between the grinding and regrinding mills. The behaviour of the selectivity curves shows that some gangue minerals are more sensitive to particle size than other ones, implying the existence of preferential associations between minerals in the ore.INTRODUCTIONInteractions between grinding and flotation have been studied for many years, and still a robust model to link the two processes lacks to be developed (Girard et al., 2005; Bazin et al., 2001). The ore size reduction liberates mineral grains, while flotation separates them into valuable minerals and gangue. The more size reduction that is applied to the ore the more important is the mineral liberation but also the production of fine particles that can pose problems during flotation (Trahar and Warren, 1976). The definition of the grinding requirement for flotation is a complex problem (Rickelton and Dell, 1977; Sosa Blanca et al., 2000; Morrison, 1993; Wei and Gay, 1999).This paper analyzes the effect of the fineness of grind using semi-batch flotation test results. The first two sections describe the test procedure and the results. The third section analyzes the results in terms of liberation and selectivity, and proposes a possible redistribution of power between grinding and regrinding mills."

Jan 1, 2006

By G. M. Ross, J. A. Scott, C. A. Laamanen, H. Shang

"Indirect recovery and use of waste heat contained in smelter off-gas is proposed to expand regions available for year-round, on-site production of micro-algae–sourced biodiesel, a fuel that could be used in underground machinery. A dynamic model of an off-gas heat exchanger describes capture and distribution of heat into open, external, rectangular micro-algae ponds. Smelter off-gas contains sufficient energy to maintain large-scale micro-algae cultivation pond temperatures above 15°C, even with winter ambient temperatures below –15°C. Results highlight opportunities that could lie in tapping these heat resources to produce renewable biofuels on-site and sequester CO2 while leaving the industrial process unaffected.RÉSUMÉ On propose la récupération et l’utilisation indirectes de la chaleur résiduelle contenue dans les dégagements gazeux des fonderies pour développer les régions se prêtant à une production toute l’année durant et sur place de biodiesel à partir de micro-algues, carburant dont on pourrait se servir pour le matériel d’exploitation souterraine. Un modèle dynamique d’échangeur de chaleur contenue dans les dégagements gazeux décrit le captage et la distribution de la chaleur dans des bassins rectangulaires ouverts de micro-algues en extérieur. Les dégagements gazeux des fonderies contiennent suffisamment d’énergie pour maintenir les températures des grands bassins de culture de micro-algues au-delà de 15°C, même avec des températures ambiantes en hiver inférieures à –15°C. Ces résultats soulignent les possibilités que pourrait offrir l’exploitation de ces sources de chaleur pour la production de biocarburants renouvelables sur place et pour la séquestration de CO2 sans que cela n’ait d’incidence sur le procédé industriel.INTRODUCTIONMicro-algae that grow in water can efficiently convertsolar energy and carbon dioxide into biomass. This biomass can be up to 50% oils (lipids), which can be extracted and converted into biodiesel through transesterification (Demirbas, 2008). Compared to terrestrial plants that produce similar oils (e.g., jatropha, soybean, and rapeseed), micro-algae represent an order of magnitude increase in areal productivity, do not require arable land, and can be continuously harvested (Rawat, Ranjith Kumar, Mutanda, & Bux, 2013). The potential advantages through the production of biodiesel from micro-algae also include sequestration of carbon dioxide, reduced reliance on fossil fuels, and the co-production of other value-added bioproducts."

Jan 1, 2017

By I. R. Ward

"The need for energy conservation has been of increasing concern since the early 1970's, when the cost of petroleum based energy began to escalate rapidly and security of supply became uncertain. The cost of energy from alternative sources has also increased due to development costs and environmental restrictions.These developments have had a serious impact on the mining industry, which is energy intensive. The impact is magnified as lower grade ores are treated, and more energy is consumed per unit of product. In many cases increased operating cost is not compensated by the rise in product selling price.The magnitude of energy consumption in the mining industry is indicated by recent studies conducted in the U.S.A. and Canada. Based on 1970 figures, it was reported that the production of 1 ton of copper in the U.S.A. required 111. 8 x 106 BTU of energy, of which 60. 7 x 106 BTU (54.3%) was consumed in mining and processing (l)The survey of Canadian mills, conducted by CANMET and reported to the CMP meeting of 1978 (2), showed the following milling energy consumption figures (approximate averages):"

Jan 1, 1981

By D. J. Kemp

The 20th century saw changes in the mining and metallurgical industry not only technically but also in social and environmental expectations. As projects continue to become larger their visibility raises concerns among many groups. For mining companies, transparency, openness, and early engagement of all parties are fundamental to assure success. An equally important task is to anticipate the standards that will be required to meet society’s expectations in the 21st century.

Jan 1, 2005

By J. T. Furey

"A pilot plant study was conducted to evaluate the performance of column flotation in the recovery of gold from a gold/tellurides bearing sulphide ore, and to compare the performance of column flotation to conventional ""mechanically agitated"" flotation.Tests were conducted in a 60 liter glass column with ground flotation feed split from a concurrently operating conventional pilot plant, thus permitting direct comparison between the two processes. During the test program, the effects of wash water rate, gas holdup, froth depth, residence time and flow bias were examined in detail.The ore had an average ""as tested"" feed grade of about 5 g/t gold and 1 % sulphur, with the gold occurring primarily as inclusions of montbragite (Au2Te3) in pyrite, with minor amounts of native gold. Conventional flotation using 60 minutes residence time across four roughing stages recovered about 97% of the gold into concentrates grading about 50 g/t Au. A single stage of column flotation roughing using 25 minutes residence time matched the conventional circuit recovery of 97%, but produced grades of+ 150 g/t Au. INTRODUCTIONColumn flotation is the most significant innovation that has occurred in the mineral processing industry in recent years and has become an important alternative to mechanical flotation. Column flotation has been most widely accepted and applied in cleaning service where it has frequently proven to be superior to mechanically agitated flotation. Roughing in columns has not been ignored, but early testing indicated that columns may not be capable of achieving adequate recovery and, to date, columns have not been seen as serious competitors for mechanical roughers."

Jan 1, 1990

By Bjarne Ekberg

"The most economical way of dewatering mineral concentrates is to reduce the moisture content in the material mechanically using thickeners and filtration avoiding thermal drying whenever possible. In addition to this, the dewatering process should produce low moisture cake, high quality liquid, consume little energy. As a part of the dewatering process The CERAMEC® capillary filter has been proven to meet these requirements in over 150 installations. The filtration is done by using ceramic filter plates with small pore size. The capillary action in the filter medium secures gas free filtration at good vacuum, and due to the small pore size, filtrate is crystal clean and particle free. The energy consumption is minimal. This paper will discuss results from filters installed at Pyhäsalmi Mine Oy in Finland where the technology was has been used since the late eighties. Results from more recent installations like Los Pelambres in Chile and LKAB in Sweden will also be discussed.INTRODUCTIONThe idea of using capillary action to make dewatering more efficient was invented two decades ago. Ten years later whole filter plants utilizing the new method were delivered to mine concentrators for dewatering of mineral concentrates. Further development of ceramic membrane plates made it possible to meet the requirements in iron ore dewatering. In addition to low cake moisture, high capacity and low energy consumption, there are a lot of environmental advantages in using capillary filtration. One of them is clear filtrate.CAPILLARY FILTRATIONA micro-porous filter material behaves like a large number of narrow capillaries forming a network. When a pressure difference ?P is applied over the wetted, hydrophilic pore with the radius r, the force striving to push the water out of the pore will be ?Ppr2. The force striving to hold the water in the pore will be the vector force 2pr? cosa of the surface tension ? and the cosine contact angle a. Equalling those forces and solving the equation for ?P we get"

Jan 1, 2003

By Euler De Souza

Backfilling in Canadian mines has been practised for close to 100 years and evidence anticipates the application of mine fill technology at an increasing rate during the foreseeable future. The evolution of backfill technology is closely related to the advancement of modern mining methods and the development of new backfill technology continues to evolve. The authors, after conducting extensive surveys of backfill practices in underground mines across Canada, have concluded that, because backfill operations employ large quantities of cement and experience large costs associated both with backfilling practice and cement use, opportunities exist for reducing backfill energy costs and enhancing the application of alternative cementing agents in backfill. Consequently, the authors have developed an alternate, equally effective and lower cost binder agent replacement for cement, and incorporated waste glass into the development of a lower cost backfill (glassfill). This paper presents the results of two design stages associated with the development of glassfill: strength development and flow performance. The advancement of this technology has reached a stage that should promote industrial implementation within the Canadian mining industry. A number of Canadian mining operations exhibit potential for plant optimization through possible binder source replacement, and might thus realize associated reductions in backfill and energy costs.

Apr 1, 2005

OVERVIEW OF PRESENTATION ? What is LMI ? Who uses LMI and how? ? Value of LMI to the Mining Industry ? Mining Industry Workforce Information Network (MIWIN) ? The Challenge: Forecasting the future in uncertain times ? Results: Hiring requirements in the next decade ? Results: Occupational information ? Next steps

May 1, 2009

By R. Venugopal, Saxena. V. K., U. Sankrityayan

"There is a dire need of a technology which can break the mineral interfaces to enhance liberation with minimum energy consumption in mineral beneficiation processes. Understanding of mineral crystal system and interfaces is essential to develop such methodology. So, this study is carried out to find out the role of mineral crystallography in milling and liberation. Data related of mineral crystallography, Vickers Hardness Number, Bond Work Index and beneficiation processes were collected from literature and detailed statistical analysis has been carried out to establish a correlation among these parameters. It was found that atomic weight and cell parameters shown statistically significant relationship with Vickers Hardness Number of minerals, which controls the milling characteristics of ores. Liberation characteristics of five different kinds of ores were analyzed considering the types of interfaces between valuable and gangue minerals. It was found that phase interfaces play vita role in liberation and coarser liberation can be achieved in the minerals of incoherent crystal systems like manganese and zinc ores. Study of this subject can help us to understand the effect of stress wave propagation in solids and its effect on crystal interfaces. It can also help us to design a technology of future to break the mineral interfaces.INTRODUCTIONCommunition is energy intensive mineral processing operation and consumes up to 2% of the total electric power generated in the world. Energy consumption due to comminution is increasing every year as there is growing needs to exploit lower grade ore bodies and process rejects (Blazy et al., 1994; DOE, 2005). Low grade ores require crushing and grinding to liberate the valuable minerals which are further separated from gangues by various beneficiation methods like gravity separation, floatation, leaching etc. Currently, comminution methods are selected based on the reduction ratio and energy consumption but effect of grinding methods on subsequent processing methods specially on liberation also need to be studied to optimize the entire beneficiation process. Most of the attempts made in past to minimize the energy consumption in milling to enhance the mineral liberation were focused on compression mechanism, chemical additives, thermal treatment, microwave treatment and electric disintegration (Kilpelm and Austin, 1982; Norgate and Weller et al, 1994; Bearman et al., 1997; Kumar et al., 2010; Wang el al., 2011; Singh et al., 2012). But the role of mineral crystallography on milling and liberation behavior of minerals not fully explored yet."

Jan 1, 2013

By Craig Naudé

"An enhanced gravity concentrator was installed in conjunction with an Intensive Leach Reactor at the Sadiola plant in Mali last year and commissioned in Dec 2007.There has been much debate over the years as to the effect of gravity concentration on overall plant performance. The late Dr Laplante suggested that for every 10% of gold recovered by gravity, there was a corresponding 0.1% to 1% additional overall plant recovery. The results at Sadiola are consistent with this hypothesis with an overall 4% gain in plant recovery.With total gold recovery of 12% in the gravity section, grades are increased from 3.54g/t in the gravity feed to an average of 2 600g/t in the concentrator feed to the in-line reactor. The recovery of gold in the in-line reactor is in excess of 98.5%.This paper discusses the background to the project, the laboratory testwork prior to the equipment selection, the operational results of the system, as well as the benefits of the future application of high mass yield centrifugal concentrators in base metals, sulphides and industrial minerals. Bench scale, pilot scale and plant practice examples are also presented.INTRODUCTIONBesides picking nuggets off the ground or out of riverbeds, gravity concentration is arguably one of the oldest methods of recovering gold. In circa 6000BC people discovered that gold can be found behind the rocks and in depressions of creek beds. By placing rocks in a stretch of channel with the proper slope the first sluice is built, probably around 4,000 BC, and this method is still practiced today."

Jan 1, 2009

By C. H. Dionne, J. A. Holmes, B. J. Huls

"Falconbridge Limited is presently developing flowsheet alternatives for implementation at the Strathcona Mill. The main thrust for change arises from the need to reject more pyrrhotite from the concentrate. To maintain appropriate levels of sulphur in the smelter concentrate, however, enhanced removal of non-sulphide gangue minerals must be realized. This could best be done in the Non-magnetics flotation circuit.Laboratory investigations were followed by an on-stream pilot test at Strathcona. The application of a column cleaner on the Non-magnetics concentrate resulted in significantly lower levels of fine gangue at equivalent sulphides recovery.This paper discusses the laboratory and pilot testing and results, with a focus on piloting. Also included is a discussion of the Strathcona Mill Flowsheet and the role of the Nonmagnetics flotation circuit.INTRODUCTIONFalconbridge Ltd. is currently developing means to reduce atmospheric sulphur dioxide emissions. One alternative is a reduction in the amount of pyrrhotite in Strathcona Mill concentrate, which reports to the smelter. Pyrrhotite in the Falconbridge ores contains an average of 39 percent sulphur and 0.64 percent nickel. By comparison, pentlandite contains an average of 33 percent sulphur and 34 percent nickel.A consequence of the rejection of pyrrhotite is a decrease in the sulphur assay in the remaining concentrate. This decrease causes downstream difficulties in the roasting process. Therefore, the content of non-sulphide gangue in the mill concentrate must also be reduced in order to maintain sulphur grades adequate for roasting. The resulting concentrate will have lower sulphur dioxide emissions while maintaining nickel production."

Jan 1, 1991

By J. R. Gordon

I-Introduction The possibility of adapting low-temperature reduction methods to the treatment of iron ores has been suggested on numerous occasions. Papers published on the subject include, notably, Bulletin 270 of the United States Bureau of Mines on The Production of Sponge Iron, the Symposium of the American Electrochemical Society (1927) on The Gaseous Reduction of Ores and Other Metallic Compounds, and Les Procédés Actuels de Traitement Direct du Minerai de Fer, by A. Mayer (Revue de l'Industrie Minerale, Nov. 15th, 1932) (1). The present paper contains the results of an investigation of the reducibility of some Ontario ores. The concentration of these ores and of the products of reduction has also been investigated.

Jan 1, 1933

By G. Winkel

"Safety conditions in industry have greatly improved over time. However, around the world, in Canada, and in each province or territory, people are still the victims of serious industrial accidents. The increasing safety of people at work then continues to be an imperative in industry today. In addition to protecting people, safety has been shown to make good business sense in any industry.The road to safety improvement is built on establishing a culture of safety that forms the basis for how work gets done in a company. Most importantly, an effective safety culture is built on the full engagement and participation of workers and leaders alike, who share in a vision for safe work performance where “no one gets hurt” and “everyone is a leader in safety.”Let’s learn together on how we can make a safety culture happen. The resulting bias for safety will ultimately save lives, and fulfills our moral objective to strive for safety excellence. IntroductionWe have the good fortune of living in democratic countries where freedom and the value of human life are key beliefs. These beliefs translate into the moral obligations and laws that we value and uphold in our society and life today.A minesite or workplace is simply a necessary part of our society where people earn a living. It is a place where our moral obligations and laws equally apply, a place where human life is of ultimate importance and value. In the early years of industry, this value has not always been evident. Take this description of a tragic accident reported in a coal mine on December 8, 1879:“Oliver Thompson, shaftman, aged 35— While taking wooden partitions out of a ventilation shaft, he fell off the work platform a distance of 100 yards, there did not appear to be anything unusual to account for this accident.”"

Jan 1, 2004

By Tom Olsen, Tom Ohrling, Peter Taggart, Chris Martin

"North American Palladium commissioned the new concentrator at the Lac des Iles mine in the summer of 2001. The 15,000 tonnes per day mill replaced the existing 2,400 tonnes per day facility, as part of a major mine expansion.At Lac des Iles, the grain size distribution of the platinum group minerals (PGM) is bi-modal. Roughly two-thirds of the PGM are relatively coarse-grained, and often associated with fast floating copper and nickel sulphides. The remainder is ultra-fine, and locked in silicates, which poses a special challenge to the metallurgist. The previous mill typically recovered just the fast-floating mineralisation, but to achieve target recoveries, the new mill has to recover a substantial amount of the ultra-fine PGM. The metallurgical challenges associated with the recovery of fine-grained PGM in the talcous Lac des Iles ores, are described.The paper describes the approach used in circuit optimisation, and how metallurgical and operational optimisation raised palladium recoveries by more than 6% in six months, by tuning the circuit to recover some of the ultra-fine PGM mineralisation.BACKGROUNDThe Lac des Iles mine, owned and operated by North American Palladium Limited, is located about 115 kilometres north of Thunder Bay, Ontario. The mine originally opened in December 1993, and prior to 2001 included a mill capable of handling 2,400 tonnes per day of ore delivered from the nearby Roby pit.Following an intensive exploration programme conducted in 1999, and a detailed feasibility study, conducted in 2000, North American Palladium initiated a mine expansion project, the objective being to expand milling throughput from 2,400 tonnes per day to 15,000 tonnes per day. This required construction of an entirely new mill, which was commissioned in May 2001."

Jan 1, 2003

By Derek J. Cyr

Climate has an immense impact on the properties of Athabasca oil sands and the ease or difficulty with which it is excavated and extracted. During the winter months, exposed oil sands surfaces freeze. When hydraulic and electric shovels used in the various operations in the Fort McMurray area excavate the benches, large frozen lumps are created. These lumps are either destined for a lump dump where increased costs are incurred due to rehandle, or they are sent to the primary crushers where they can cause significant downtimes by jamming the crusher. The crusher down time can sometimes be in the order of hours of lost production. Studies on data from two consecutive winters at Syncrude Canada?s North Mine show a high correlation between climate and the generation of frozen oil sands lumps. Temperature, ground cover, traffic, bench exposure time, oil sands grade and moisture content all contribute to this problem. A 1D frost penetration model was used to predict the depth of frost expected in oil sands and the corresponding likelihood of frozen oil sands lumps. To combat the challenge of frozen lump generation, a number of proactive and reactive measures can be taken: artificial snow, shallow ponds, scheduling, blasting or ripping.

May 1, 2004

By Carolyn Kenney, Jianjun Liu, Zhenghe Xu

"The flotation of fine particles has been a challenge to scientists and engineers in mineral processing. A novel concept of reactive oily-bubbles as carrier to float fine particles is described in this paper. The reactive oily bubble flotation is considered attractive for fine particle flotation. In addition to the role of fine particle agglomeration by oily films, the surface properties of air bubbles coated with a thin oil film can be better controlled for the desired selectivity by adding certain types and concentrations of water insoluble collectors into the oil phase. This approach can eliminate the addition of collector to the aqueous phase, avoid undesired synergetic interactions among collectors, activators, depressants and dispersants present in slurry, minimize undesired activation of gangue particles and significantly reduce the amount of collectors needed.The concept of using reactive oily-bubble to achieve selective flotation was demonstrated in contact angle measurement and by microflotation tests with fine sulphide minerals: sphalerite and galena in this paper. The flotation behavior of sulfide minerals can be radically modified with adjustment of solution pH, addition of depressant and activator as in conventional flotation. The successful separation between PbS/SiO2, ZnS/SiO2 and PbS/ZnS was demonstrated using mixed mineral systems. Compared with conventional flotation, the reactive oily-bubble flotation showed a stronger collecting power.INTRODUCTIONThe challenge for fine particle flotation has long been recognized and well documented (Fuerstenau, 1980). Because of drastic changes in surface properties of fine particles and associated physicochemical and hydrodynamic conditions of flotation systems, fine particles responded poorly to the conventional flotation processes. For instance, the small mass and hence low inertia of fine particles would result in a low efficiency of collision and attachment of fine particles with flotation bubbles. Large specific surface area of fine particles, on the other hand, would cause an increased reagent consumption. Dominating colloidal forces of fines may cause slime-coating, accompanying a low selectivity (Somasundaran & Arbiter, 1979; Fuerstenau, 1980; Sivamohan, 1990)."

Jan 1, 2003

By I. Jackman

"Gold is present in different forms and associations in different ores. Flotation is used to recover gold and minerals associated with gold, but the applicability and type of flotation vary. The purpose of flotation in a gold recovery plant is largely dependent on the mineralogical association of the gold, and environmental and economic considerations. In this paper, the role of flotation in the recovery of gold is reviewed. The paper will describe examples of gold recovery by flotation including flotation of native gold, gold associated with sulphides including specifically copper sulphides, gold associated with tellurides, gold ores containing carbonaceous material and gold contained in tailings.INTRODUCTIONFlotation is widely used in the recovery of gold. However, the objectives and the mode of application are quite variable dependent on the type of ore, the gold association(s), other metal values, marketing considerations and environmental requirements. In this paper, a range of different applications of flotation incorporated in the recovery of gold are discussed. The reasons for each particular application are outlined and metallurgical results are presented.The mineralogy of the ore and the gold associations are fundamental influences on gold recovery. The use of flotation to concentrate gold is dictated by the mineralogy of the ore and gold. The fundamental factors are mineral/gold size, liberation size, association of the gold and type of gangue minerals or other valuable minerals. Gold can exhibit a range of sizes in a host from relatively large size (+50 µ) to refractory size (1 µ and sub-micron size). Similarly, the gold can occur in a number of phases in the same host. For example, the gold was present as petzite (AgAu telluride), calaverite (AuTe2) and native gold in a gold telluride ore and each of these minerals was associated with the pyrite host.Understanding the gold mineralogy and association is important in establishing the correct process route. The gold mineralogy is established by good mineralogy, use of diagnostic tools such as diagnostic leaching and assay by size fraction analyses and basic metallurgical testwork."

Jan 1, 1995