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By Frédéric Flament, Luc Lachance

"The important task of metallurgical accounting that used to be done manually is being more and more automated. Currently available solutions can generate accounting reports without human intervention or almost. However, the practical conditions for fully delivering the promised benefits of those solutions are sometimes overlooked either by end-users or by integrators. The mere fact of filling reports with values satisfying several constraints such as mass conservation constraints does not, by itself, ensure a high quality metallurgical balance. Since managers make decisions based on these reports, it is logical that the metallurgical balance performance be monitored and retrofits be made if necessary. Such retrofits may involve modifications to the measurement strategy or the reduction of the spatial resolution of the material balance model. This requires an estimability and redundancy analysis (ERA) tool to assess the feasibility of the modified model. Since determining by hand the estimability and redundancy of a set of non measured and measured variables is not trivial, even for a medium-sized mineral processing plant, a dedicated ERA tool brings valuable assistance to the metallurgist in charge. The present paper aims first at explaining how a state of the art metallurgical balance is a key enabler for the adoption of a smart process plants paradigm (SPPP) in mineral processing. Then, the fundamentals behind the building of an ERA algorithm are introduced and illustrated by two examples. Finally, the role of an ERA tool in achieving state of the art metallurgical accounting and how it contributes to delivering additional value are discussed.INTRODUCTIONThe Smart Process Plants Paradigm (SPPP)Mineral processors have seen an increase lately in external pressures toward operating performance improvements. Indeed, the globalization of the mining business is a key driver to becoming more productive, more responsive to market changes, to improving corporate governance and reporting standards. Furthermore, mineral processors are also expected by their neighbouring communities to continuously improve their sustainability score. These current pressures differ somewhat from the past ones in leading to a larger than ever number of conflicting constraints that plant managers must concurrently satisfy while maximizing plant profitability. It is in turn not surprising that this context requires actions involving more real-time collaborative actions between more people in more places than ever before."

Jan 1, 2011

Background Chronology 2008 Positions May 8, 2010 Summit Going Forward Say one thing and do another ??Genuine passion to see our customers succeed?, ?A passion for exceeding our customer?s expectations? Self serving actions to gain competitive advantage at the expense of the customer No single supplier or technology can manage the overall mine and its integrated operation - April 2005: Informal meeting at Toronto CIM 2004 -Unanimous interest - July 2005: Formal Calgary Meeting, developed: - Scope and vision statement , - OEM/OTM communication plan, - industry communication plan - Aug?Nov 2005: Aligned with SMART - Nov 2005?May 2006: Direct OEM, OTM communication - May ?Sept 2006: Developed baseline standards - Sept -April 2007: Developed SMART document - Sept 2007: Document distribution and request OEM OTM response - Jan ?May 2008: Acquired OEM OTM feedback and positions May 2008: Results presented to SMART and discussions on next steps

May 1, 2010

By S. Haggarty

"Wholly owned by Corona Corporation, the Nickel Plate Mine is an open pit, gold mining operation located near Hedley, 50 km west of Penticton, in Southern British Columbia.Milling capacity is 3,400 SDT /Day with an average feed grade of 0.080 Oz Au/Ton. Gold processing involves three stage grinding including tertiary pebble milling, two stage cyanide leaching and filtering and Merrill-Crowe zinc precipitation.A summary of process improvements required to increase milling capacity above the initial design tonnage of 2, 700 SDT /Day are described -Installation of a 42"" x 65"" Allis Chalmers Gyratory crusher replacing a 42"" x 48"" Traylor jaw crusher.Installation of polyurethane screen panels replacing woven wire cloths on an 8' x 20 ft triple deck screen.Installation of a hopper clarifier to reduce filtrate turbidity.Automated control of solution balancing and effluent treatment circuits.INTRODUCTIONThis paper describes mining and milling practices at the Nickel Plate Mine and details post start-up process modifications which were required to attain design tonnage.Wholly owned by Corona Corporation, the Nickel Plate Mine is an open pit, gold mining operation located near Hedley, 50 km west of Penticton, in Southern British Columbia.Mining capacity from the open pit is approximately 32,000 TPD with an average waste/ore ratio of 8.4:1.Milling capacity is 3,400 SOT/Day, above initial design tonnage of 2,700 SOT/Day. Feed grade averages 0.08 Oz Au per ton yielding 85,000 troy ounces of gold per year."

Jan 1, 1991

By Gabka T., R. E. Gregorczyk

Work to improve employees' behavior in Głogów Copper Smelter began in 2009. It has been noted that over 90% of accidents at work are attributable to human reasons. At that time, a series of external workshops was contracted based on exercises conducted by a psychologist trainer with supervisors. Having trained about 300 employees, an observation of employee behavior at workstations was started as part of the control of risk reduction measures. As a result of the above actions, the number of accidents was reduced by half between 2009 and 2017. Currently, internal workshops for communication improvement for behavioral auditors are conducted by the employees of the Smelter. Named: "I observe, react and communicate" and aimed at further mastering the elements of the safety culture in Głogów Copper Smelter. INTRODUCTION KGHM Polska Miedz is an integrated mining and smelting copper producer based in Poland and operates on the international metal market. KGHM, with annual production of over 500 thousand tonnes of copper, holds a middle position in the world ranking of copper producers. At the same time, in Europe it is the largest producer of copper from its own ore deposits, possessing its own integrated production structure, from underground mining operations to final, top-quality product. It is also worth mentioning that KGHM Polska Miedź is one of the largest Polish exporters and, apart from copper, is a significant primary silver producer in the world. The mission of our company, consistent with its strategy, is to produce copper and silver in a safe mode for workers and the environment, with reduced environmental impact. Therefore, "Głogów" Copper Smelter operations are continuously focused on the creation of safe working conditions, and minimizing the negative effects on the environment. The company meets the requirements of an Integrated Management System comprised of the following: Quality Management System ISO 9001:2008 Environment Management System ISO 14001:2004 OHS Management System according to the requirements of BS OHSAS 18001:2007 Being a proud socially responsible company, we are aware that part of an efficient OHS system is to recognize, monitor, prevent, educate and motivate, thus continuously improve working conditions for 2500 employees of Głogów Copper Smelter &Refinery. We clearly communicate that a low accident rate is beneficial for both, staff and the company, and is of utmost importance as a part of our health policy.

Jan 1, 2019

By Michel Robert

"In 1974, Copperfields Mining Corporation and Soquem formed a new company, Niobec Inc, to bring the niobium deposit of the St-Honore carbonatite into production.St-Honore is located in the Saguenay area, near the cities of Chicoutimi and Arvida, and about one hundred and forty (140) miles north of Quebec. The discovery of the carbonatite complex was made in the fall of 1967 as a result of an airborne radiometric survey in search of uranium. The detailed exploration of the carbonatite indicated two niobium-bearing formations besides the original discovery of a rare earths zone. During the following years, the niobium formations were defined by diamond drilling and a decline was driven down to obtain adequate samples for metallurgical evaluation. In 1974, after seven hundred (700) bench scale tests, eleven (11) months of pilot plant 2nd a worldwide market research, a joint decision was made to initiate the development of a fifteen hundred (1500) T.P.D. mine and mill, under the management of Teck Corporation. The construction of the facilities were completed in early 1976 both on time and within budget. Niobec is now the only north american and the world second largest producer of Niobium concentrate.The process used at Niobec was developed from the pilot plant programs and later modified by the mill personnel. A simplified flowsheet for this process is shown on the slide. Briefly, run of mine ore is crushed to minus 5/8"" and fed to a rod mill, ball mill, and screens circuit where the ore is ground to 92% passing 65 mesh. The ore is deslimed in two stages of cycloning, and the final cyclone overflow at 85% minus 11 microns goes to waste. The cyclone underflow is conditioned prior to flotation of a carbonate-apatite concentrate. This concentrate is cleaned twice and then pumped to tails. The carbonate rougher and cleaner tails are cycloned in two stages to change the process; water and then sent to the pyrochlore rougher flotation. The rougher concentrate is cleaned five times. This is followed by pyrite flotation to remove sulfur, leaching with hydrochloric acid to remove phosphorus and dyed to less than 0.1% moisture before being sent to packaging."

Jan 1, 1978

By Wei Sun, Jaewon Choung, Zhenghe Xu, Zhangming Cui

"High intensity conditioning has been demonstrated in a number of cases to enhance fine particle flotation. The improvement could be attributed to the enhanced formation of particle aggregates. However, the understanding of aggregation mechanisms remains rather limited. Recently, an enhanced particle aggregation was observed by the formation of small air bubbles resulting from high intensity agitations (HIA). In this study, a novel visualization system is designed and constructed for characterizing the fine bubbles formed in an HIA cell. The new design allows determination of gas evolution and bubble size distribution. With this system, the effect of dissolved air on fine bubble generation by HIA is investigated. The results show that HIA creates a favorable environment for the formation of gas nuclei and small size bubbles due to hydrodynamic cavitation.INTRODUCTIONFlotation is a dominant separation technique employed by mineral industry to recover the valuable mineral particles. However, in general, particles finer than approximately 10 µm are not effectively recovered by conventional froth flotation technique due to their low inertia and high specific surface area (Fuerstenau, 1988). Therefore, the fine particle flotation has been considered as the central challenge of flotation research. Substantial advances have been made for fine particle flotation from both a theoretical and technological point of view (Fuerstenau et al., 1979; Song and Lu, 1990; Subrahmanyam and Forssberg, 1990; Sivamohan, 1990; Sedat and Barry, 1991; Matis, 1995). High intensity agitation (HIA), for example, has found some success to improve fine particle flotation kinetics in laboratory tests (Chen et al., 1999a and 1999b; Valderrama and Rubio, 1998; Rubio and De Brum, 1994).The effect of mechanical agitation on flotation kinetics has been recognized for many years. In mid-1970s, Warren (1975) reported that increasing the shear rate of the pulp could improve the efficiency of ultra fine particle flotation. He attributed this improvement in flotation to the formation of aggregates. This concept of aggregation has been extended by Rubio (1978), and Bulatovic and Salter (1989), who employed high intensity agitation (HIA) method to promote aggregation. They found that HIA with the addition of collectors, frothers and suitable modifiers significantly improved both the flotation recovery and selectivity of ultra fine sulphide minerals. The improvement was explained by warren’s shear flocculation theory. Till now, many studies (Chen et al., 1999a and 1999b; Valderrama and Rubio, 1998) have been undertaken to improve fine particle flotation by HIA. However, most of these studies were focused on the relation between energy input and flotation efficiency. Less information was available for describing how the aggregate formed during HIA process."

Jan 1, 2006

By Tony Moore, Peter Riccio

"MMG (Minerals and Metals Group) operates the LXML Sepon’s mineral processing facility located 40 kilometers north of the town of Sepon, in the Savannakhet Province, Lao PDR. The Sepon copper plant produces 70,000 tons/year of LME grade A copper cathode using leachautoclave- SX/EW-flotation technology (Baxter et al., 2003). Pyrite recovery in the flotation circuit is critical to the operation, as it is used to generate acid and soluble ferric ion for the leach circuit. Low pyrite recovery has been an on-going challenge in the flotation circuit. Final tailings characterization work done by Ian Wark Research Institute (Bassell et al., 2006) showed that the pyrite losses to the tailings are made up of a combination of coarse liberated particles and finer particles that have been coated by clay fines.In December of 2005, a joint Cytec-MMG technical program was initiated to address the pyrite recovery issue. A series of diagnostic tests were performed in the Cytec Stamford Research Facility using synthetic plant water showing that the collector was precipitating as a metal salt and was unavailable for mineral attachment. The tests also identified several collector chemistries that would likely be robust in the low pH (< 1), high dissolved metal ion environment and will not complex with metal ions in solution. With the support of the Sepon on-site engineers, an extensive, successful laboratory program was completed, which was subsequently followed by on-plant testing that showed a step wise improvement in pyrite recovery.INTRODUCTIONLow pyrite recovery has been an ongoing problem in the flotation circuit at Sepon. Sulfur recovery (indirect measure of pyrite) was improved from 40% to 65%-75% in mid-2005 when on site laboratory work confirmed that AERO® 8045 Promoter was a more effective collector then AERO® 407 Promoter. However, sulfur recoveries above 65% could never be achieved. Sepon requested the Ian Wark Research Institute to complete a surface analysis study using Scanning Electron Microscopy, X-ray Photoelectron Spectroscopy, and Time-of-Flight Secondary Ion Mass Spectroscopy to determine if clay coated pyrite played a role. It was concluded that the pyrite losses to the tailings are made up of a combination of coarse (+ 100µm) liberated particles and finer (-74µm) particles that have been coated by clay fines. The majority of the losses appear to be due to the former. In December of 2005, a series of diagnostic tests were performed in Stamford using synthetic plant water in order to identify what chemistries would likely be robust in the slimy low pH and high dissolved metal ion solution environment. Results showed that several chemistries would not complex with ferric, ferrous or copper in solution and therefore should perform well in the Sepon flotation. The incumbent collector, AERO® 8045 Promoter was complexing with metal ions in solution. This resulted in the collector not being available for adsorption onto pyrite."

Jan 1, 2011

By F. D. Ford, Z. Dai

"Vale’s Ontario Operations re-introduced Cu/Ni separation at Clarabelle Mill in 2006. The mill processes ores from a number of mines in the Sudbury basin. A saleable Cu concentrate is produced at 30-60% Cu recovery from mill feed, which has to meet the quality specification. In particular, Ni content in Cu concentrate must be less than 0.6%, otherwise, penalties will apply and diminish the value of Cu concentrate, in addition to the lost Ni value. Generally, a Ni grade of less than 0.4% is obtained in Cu concentrate. More recently, while processing Cu-rich ore, Cu concentrate contained more than 0.6% Ni which is abnormally high. Detailed mineralogical investigation shows that Cu-rich ore contains more millerite in comparison to typical Sudbury Ni sulphide ore. Millerite is found to be more floatable than pentlandite and is much more difficult to depress using high-lime aeration conditioning, which is the standard practice in Cu/Ni separation to float chalcopyrite while depressing pentlandite. The current operation uses sodium cyanide at 20 g/t to depress pentlandite and pyrrhotite. However, it is found that a high dosage is required to depress millerite. It is also shown that starch and dextrin are promising in millerite depression.INTRODUCTIONPrior to bulk smelting in 1991, Cu/Ni separation was carried out at Vale’s Copper Cliff Mill, Ontario Operation. The typical Cu concentrate grade was around 30% Cu and 1% Ni. This is very high in comparison to today’s value of 0.4% Ni and would not be acceptable for external processing. However, the Cu concentrate was processed internally at the Copper Cliff smelter/refinery, so the Ni contained in Cu concentrate was not lost and no actual penalties applied. During the SO2 abatement initiative, bulk smelting was chosen because of the perceived simplicity and consequently, Cu/Ni separation was eliminated (Agar, 1991) and the Copper Cliff mill was subsequently demolished. In 2005 and after more than one decade of bulk smelting, business changes required the removal of some Cu concentrate from Clarabelle Mill bulk concentrate to provide smelter capacity for Voisey’s Bay concentrate in the Copper Cliff smelter. In essence, this strategy calls for Cu removal at Clarabelle Mill (Lawson, 2006). In this case, Cu concentrate is sold externally and it must meet the quality requirement of less than 0.6% Ni."

Jan 1, 2011

By M. Rantapaa

Measurable improvements in throughput have been documented at Barrick Goldstrike due to increased ore fragmentation through efficient drilling and blasting techniques. A decrease in throughput at the autoclave, due to increasingly hard ore, was identified in early 2002. A team of individuals from the open pit and process areas worked closely on the Drill-to-Mill (D2M) Continuous Improvement initiative to ensure that it would address the needs of both groups, with the target of actually improving throughput in future years, despite the projected harder ores. A series of tests were conducted to determine if adjustments to drilling and blasting could positively influence throughput. Better fragmentation and a subsequent increase in mill throughput were achieved through the use of electronic caps for more precision and flexibility, as well as for allowing extremely fast shots; explosives with a higher velocity of detonation (VOD) to provide for improved shock energy; and improved distribution of the explosives by decreasing pattern spacing. Early tests indicated a significant increase in throughput when processing identified harder ore. It is anticipated that the total process throughput (hard and soft ore) will increase by 6 tph in 2003 due to the improved fragmentation of the hard ore. Barrick Goldstrike?s D2M initiative includes roaster hard ore (BWI>17), as well as autoclave hard ore (BWI>15). Approximately 6 million tons of D2M material were shot in 2003, a relatively small amount compared to the 150 million tons to be mined. The benefit of additional ounces produced should far outweigh the additional drilling and blasting costs.

Jan 1, 2005

By R. Mckinstry, M. Rantapaa, T. Bolles

"Measurable improvements in throughput have been documented at Barrick Goldstrike due to increased ore fragmentation through efficient drilling and blasting techniques. A decrease in throughput at the autoclave, due to increasingly hard ore, was identified in early 2002. A team of individuals from the open pit and process areas worked closely on the Drill-to-Mill (D2M) Continuous Improvement initiative to ensure that it would address the needs of both groups, with the target of actually improving throughput in future years, despite the projected harder ores. A series of tests were conducted to determine if adjustments to drilling and blasting could positively influence throughput.Better fragmentation and a subsequent increase in mill throughput were achieved through the use of electronic caps for more precision and flexibility, as well as for allowing extremely fast shots; explosives with a higher velocity of detonation (VOD) to provide for improved shock energy; and improved distribution of the explosives by decreasing pattern spacing. Early tests indicated a significant increase in throughput when processing identified harder ore. It is anticipated that the total process throughput (hard and soft ore) will increase by 6 tph in 2003 due to the improved fragmentation of the hard ore.Barrick Goldstrike’s D2M initiative includes roaster hard ore (BWI>17), as well as autoclave hard ore (BWI>15). Approximately 6 million tons of D2M material were shot in 2003, a relatively small amount compared to the 150 million tons to be mined. The benefit of additional ounces produced should far outweigh the additional drilling and blasting costs."

Jan 1, 2005

By Dave Bulled

"This paper describes the design of a molybdenite flotation circuit using FLEET technology applied to kinetics data produced from laboratory flotation testing and distributed across the blocks of a mine plan using a geostatistical approach. The geostatistics assigned the statistical error that arises from having a limited amount of sample testing data to the kinetics estimates of each block of ore in the mine plan. The final design then included a quantification of risk based on the accuracy of the block flotation kinetics and model fitting. The design made reference to the extensive technical reports describing earlier metallurgical test work including some pilot plant work over thirty years ago.The testing involved conducting MinnovEX Flotation Tests (MFT) to determine the rougher flotation kinetics at the specified reagent conditions and rougher-cleaner tests to determine the change in kinetics resulting from regrind. These flotation kinetics were used within FLEET simulations to create a full-scale flowsheet and plant design including recommended equipment sizes and the forecast of operating results. Measurement of detailed flotation kinetics for a wide range of samples allowed the effect of size of grind and efficiency of classification (i.e. width of size distribution) to be predicted for the whole ore body.INTRODUCTIONAdanac Moly Corp. proposed to develop a 20,000 ton per day mill to produce high quality molybdenite concentrate from its Ruby Creek resource in north-western British Columbia. It is a relatively clean low grade porphyry-monzonite occurrence containing minimal quantities of other sulphides such as chalcopyrite, pyrite, sphalerite and galena. Molybdenite occurs mainly as coarse flakes with lesser amounts of finer sized values. An optimum plant design was required to can achieve the predicted operating results, at a known level of risk, while treating the variability inherent in the ore body."

Jan 1, 2007

By Todd Smith, Brigitte Lacouture, Greg Anderson, David Lin

"The lead and zinc flotation circuits at Red Dog Mine are preceded by a preflotation circuit which recovers naturally-floating organic carbon contained in the ore. Organic carbon is a potential contaminant in the lead concentrate and is detrimental to lead-zinc selectivity. Prior to 2007, the Red Dog preflotation circuit consisted of a single stage bank of tank cells which floated the organic carbon. The preflotation concentrate was discarded directly to tailings, however, this stream contained significant amounts of lead and zinc. Zinc loss to preflotation ranged from 2% to 6%, relative to the zinc in the mill feed and was proportional to the amount of organic carbon in the ore. The main mechanism of the zinc loss was entrainment.Pilot plant and modeling testwork were conducted to examine the use of a Jameson Cell to clean the preflotation concentrate. Results indicated that up to 90% of the zinc deporting to preflotation concentrate could be returned to the flotation circuit for recovery. The installation of a 5.4 m Ø Jameson Cell with 18 downcomers was initiated in June 2006. The new preflotation cleaning circuit was commissioned in March 2007. Conservatively, preflotation cleaning has resulted in zinc and lead absolute recovery gains of 1.0% and 1.5%, respectively. The $9.1M project has a payback period of approximately 1 year at current metal prices.INTRODUCTIONRed Dog Preflotation CircuitRed Dog Mine is located above the Arctic Circle in northwest Alaska. It is the world’s largest zinc concentrate producer with a production rate of more than 1.0M t/yr. Red Dog is operated by Teck Cominco Alaska Incorporated under an operating agreement with the Northwest Alaska Native Association (NANA). Due to the remote location of the mine, it is accessible only by air, or seasonally, by ocean-going barges.The Red Dog deposit is a rich sedimentary exhalative (sedex) zinc-lead-silver deposit. The major sulphides, in decreasing order of abundance, are sphalerite, pyrite, galena and marcasite. Due to the complex nature of the ore body, run-of-mine ore is blended in stockpiles before being crushed and processed through the concentrator. The average mill feed grade for 2006 was 6.1% lead, 20.6% zinc, 8.0% iron and 0.67 % organic carbon."

Jan 1, 2008

By A. Vien, B. C. Flintoff, R. P. Edwards

"This paper provides a critical review of the development and application of advanced controls in mineral processing at the industrial level. These algorithms can be sub-divided into four broad categories: Kalman filter, self-tuning, extended horizon, and knowledge based or expert systems. Applications from each category are described outlining the benefits derived, the relative advantages of that particular controller, and potential limitations of the controller which may inhibit their more widespread application. The paper will conclude with a description of control algorithms which are currently in the rudimentary design stage, but may hold tremendous potential for mineral processing control systems in the next decade. INTRODUCTIONThe Canadian mining industry has a large installed milling base and many plants are run with manual or low level automatic process control. The competitive pressures imposed by the market will not allow these operations to ignore the significant increase in efficiency that can be achieved through the effective application of advanced process control. These improvements will come in the form of better quality, higher productivity and reduced costs.There have been quite a number of reports of successful applications of advanced control in mineral processing applications. As this trend continues, and more of the work is documented, the technology will be more effectively transferred to process and control engineers. It is the authors' opinion that the most difficult problems facing process control are not really technical in nature. Rather, they lie more in process control education. This extends from management, through engineering to the operators.The purpose of this paper is to provide a tutorial type overview of some of the more frequently encountered advanced control algorithms. The assumption is that the reader has a superficial knowledge of this technology. In the discussions which follow, several techniques are explored within the framework of simple process examples. Industrial examples are cited for each and an evaluation of the expected longer term potential is given."

Jan 1, 1992

By Steven Townend

Mining-related activities have been known to create a challenging operating environment for mining companies located in close proximity to communities. Issues such as noise, vibrations from mining operations, land use and emissions are often a concern for community residents. In order to develop good community relationships it is necessary to take a proactive approach. This paper documents this approach and also deals with the social implications for Vale associated with mining activities in the heart of the community of Copper Cliff, Ontario, Canada.

May 1, 2011

By A. F. Banks

"The last time I spoke to you the potash industry was at a low point. Markets were bad and the industry depressed. Many people had left and there was very little being done in terms of development. The current situation is very much changed. The oversupply conditions have given way to a very tight supply capability. All of the firms in the business are expanding in one way or another. These expansions will run from simple debottlenecking through to complete new projects.In New Brunswick, the Potash Corporation of America is proceeding with a new project and the Dennison - Potacan Project is in progress. In Saskatchewan, the Potash Corporation of Saskatchewan has an ambitious 2.5 billion dollar expansion program underway while those in the private sector are taking a somewhat less ambitious but equally significant approach to obtain further tonnage out of existing facilities.The significance of these expansions to mineral processors is that we can expect to see expanded employment opportunities and through necessity a surge in innovation and development in an industry that has been traditionally very conservative. This presentation will review potash processing with a view towards highlighting some of the more recent developments."

Jan 1, 1982

By G. A. Kosick, G. S. Dobby, O. Matwijenko

"A 100 kg/hr portable flotation pilot plant has been operated at Kidd Creek Mines with the objectives of:(a) determining performance expected by column flotation circuits on primary zinc and copper cleaning, and (b) evaluating column flotation circuit configurations.The self-supporting pilot plant, owned by Minnovex Technologies Inc. and operated by Minnovex and the University of Toronto, consisted of three 16 cm diameter by 6.5 m high columns and a bank of four Denver No. 7 cells. It was configurable to any arrangement using these four (or fewer) units. The columns were controlled through the use of multiple pressure transducer measurements. This paper presents the approach to testing and the results of more than 70 circuit tests. INTRODUCTIONThe integration and retrofitting of flotation columns within existing mechanical cell flotation circuits is becoming a common occurrence. The correct approach to this integration, however, is often difficult to define, due to a scarcity of previous experience and the difficulty in predicting column circuit performance. In most cases, the effect of column implementation has been experimentally assessed using a single pilot column, with the consequence that selection of an appropriate circuit to implement is difficult. Important considerations are the impact that column water addition will have on the existing operations, and the differences between mechanical cell and column performance in integrated cleaning circuits.To address the problem of circuit selection a portable flotation pilot plant, consisting of both columns and mechanical cells, was designed and constructed by Minnovex Technologies. The pilot plant was structured for complete flexibility of circuit configuration, with the intent to provide a means by which both research and plant personnel could determine the best possible column circuit configuration for a given application."

Jan 1, 1990

By John G. Peacey, Leoncio Sevilla G., Ford. Kevan J. R., Erling Villalobos C.

"Kinross Gold Corporation’s Mantos de Oro (MDO) gold/silver mine in northern Chile currently processes 15,000 tpd of oxide ores through a mill, whole ore cyanide leach plant followed by a Merrill-Crowe refinery. With the expected depletion of these oxide ores in a few years a new sulphide mineral deposit, Ladera-Farellón has been identified to potentially replace existing ore reserves. The deposit contains approximately 0.5g/t Au, 6g/t Ag and 0.5% Cu. The principal sulphide mineral in the deposit is enargite (Cu3AsS4) which hosts the majority of gold and silver and the copper. Direct cyanidation testwork has shown the sulphide mineral is refractory with a low gold recovery of 36% and silver recovery of 45%. Oxidation of the sulphides is required to liberate gold and silver and allow recovery of copper as an important pay-metal. Therefore, at MDO a new metallurgical process route with oxidation as a pretreatment step is required for viable treatment of such new sulphide mineralized material with acceptable recoveries of pay-metals.Analysis of flowsheet options was completed based on bench-scale and pilot scale metallurgical testwork as well as with reference to existing studies and operations. The process options investigated assume concentration of sulphides by flotation, followed by either pressure oxidation, bacteriological oxidation or roasting. Preliminary evaluation of flowsheet options focused on process risk, operability, technology availability and the economics of the project with emphasis on use of the existing metallurgical plant to reduce capital cost. Operating costs for each process option were also included in the relative analysis.The challenges of treatment of MDO sulphides, principally enargite and pyrite for recovery of gold, silver and copper center on fixation of arsenic and sulphur capture with environmentally acceptable disposal of residue tailings. This environmental focus was included in the process option selection and comparative analysis.This paper presents a review of the process options considered and highlights comparative advantages/disadvantages of each process with associated environmental issues. Preliminary conclusions are drawn on roasting as a potentially favorable process option for the treatment of MDO sulphides."

Jan 1, 2009

By C. D. Shackelford, J. F. Muñoz, M. Vauclin, P. Rengifo, A. Suazo

The results of a field-scale study involving in situ leaching of copper ore tailings using sulphuric acid as the leaching agent, injection wells to introduce the leaching solution and extraction wells to recover the copper-enriched pregnant leaching solution are presented. The study was performed at an abandoned tailings disposal site using a battery of injection and extraction wells. The medium was characterized through the determinations of physical, chemical, mineralogical, and hydro-dispersive properties based on laboratory and field tests, including a tritium tracer test, a pumping test, particle size analyses, and hydraulic conductivity tests. Numerous horizontal strata with different hydraulic conductivities were identified. A previously developed model was used to simulate the leaching of copper ore tailings. Although the study confirms the feasibility of using in situ leaching for recovery of residual copper from tailings deposits, the efficiency of the technology depends significantly on the medium stratigraphy and hydraulic conductivity.

Jan 1, 2001

By Xing Jin, Dan Graffi, Glenn MacPherson, Dan Rioux

"The complexity of a modern flotation circuit makes it susceptible to disturbances such as changes in feed, ore mineralogy, equipment degradation, poor measurements and faulty instruments. Good measurements and a robust control system are critical to create and maintain a stable and optimum flotation process.This paper focuses on the development and implementation of process control applications in the flotation circuits at Xstrata Nickel’s Strathcona Mill ( referred to as the mill hereafter ) in Sudbury, Ontario. Following the path of ‘stabilize-improve-optimize’, basic controls to stabilize process variables such as flotation cell pulp level, air and reagent addition rates, cleaning-column feed and wash-water rates have been established. Factors such as best practice in pulp level and valve position measurement, feedforward control and the application of an appropriate control philosophy, have contributed to the significant reduction in process variability. For instance, standard deviation reduction of 79% for the Ni impurity in the column Cu concentrate grade was experienced and is shown. The variability reduction of the flotation circuits’ key process-variables paves the way to further improve and optimize flotation performance. A grams-per-metal unit reagent addition control scheme has been improved upon, particularly for different operating scenarios and better robustness. In addition, following significant stabilization of the primary controls and columns feedrates, Cu/Ni separation cleaning-column bias-control (cascaded to the wash-water rate) and hold-up control (cascaded to air flowrate) have been developed and tested. This strategy – from stabilization to optimization - is expected to achieve a more consistent control of final concentrate grades and improve recoveries.INTRODUCTIONFlotation is considered the most important and value-added process in the milling metallurgical plant and is still undergoing continuous evolution to treat greater tonnage and different ores (Wills, 2006). Starting over three decades ago, with the advent of on-line slurry content analysis devices, flotation automatic control has received persistent interest and a large number of applications have been reported (Thwaites, 1983, 1986 ; Mckee, 1991). Bergh and Yianatos (2011) reviewed different aspects of process control in flotation circuits and have evaluated the applicability of model predictive control to the process. Mckee (1991) analyzed the difficulty in developing lasting/robust process control applications for flotation circuits and stated that the path of stabilization-refinement-optimization would more likely lead to successful flotation circuit process control. Best practice on column process control was discussed by Bouchard, etc. where a multi-layered approach was proposed, provided that the measurement of column process variables ( i.e. bias, froth depth, hold-up, etc. ) are measured reliably (Bouchard & Thwaites, 2008). Wills (2006) stated that the best practice for flotation automatic control starts with fulfilling basic control objectives, such as stabilized flotation cell level, air flow, pH, reagent flow etc., before considering more advanced, or even optimal, control of metallurgical targets, which are more closely linked to economic performance."

Jan 1, 2013

By Gilles Landry, Mohamed Ourriban, Pierre Pelletier, Ahmed Bouajila, Claude Gagnon

"This paper summarizes the work carried out to develop and implement the gold cyanidation by size class (CSC) process, a novel concept aiming to reduce cyanide consumption.First, the authors will present the methodology and results of laboratory tests conducted to evaluate the response and the expected gains for the selected ore when submitted to the CSC processing. In the second part, focus will be on the methodology behind the CSC scheme development prior to its implementation at Sleeping Giant Mine concentrator. Finally, the evaluation of the modified circuit performance (operating since July 2007) will be addressed as a reduction of cyanide consumption by more than 30% and of free NaCN in the tailings by more than 50% is confirmed.INTRODUCTIONCyanidation is the most widely used technique to extract gold from hard rock ore. Its use of oxygen as an oxidant still makes it the cheapest process available after more than a hundred years. Unfortunately, gold cyanidation is known to be a slow process that requires high consumption of cyanide. In fact, cyanidation plants are designed with very long residence times (Habashi, F., 1967). Drawbacks of long cyanidation times are, among others, loss of gold in tailings, high reagent consumption and high capital investment and maintenance costs.Responding to their members expectations for the improvement of cyanidation process, COREM undertook a challenging R&D program covering the development of alternative concepts (processes) and the understanding and solving of mass transfer, gold passivation and process water chemistry problems. One of the interesting findings of the R&D program is a patent pending process technology based on the cyanidation by size class (CSC) concept (Côté and Ourriban, 2004; Gagnon and Ourriban, 2007; Gagnon and Ourriban, 2004).The new technology was tested at the Sleeping Giant concentrator, a plant member of COREM. The existing flowsheet was modified in order to implement the CSC process in the full-scale plant. The plant has been operated using the modified CSC based process since August 2007. Laboratory testwork was conducted prior to the industrial application in order to properly design the new process scheme. The modifications included:1) Reclassification of the grinding circuit product through an hydrocyclone2) Leaching of the coarse size fraction3) Addition of the fine fraction to the coarse leaching circuit tails."

Jan 1, 2009