Search Documents

By Jim Dodd, Jim Paynter

"We would like to acknowledge the efforts of the following key people who helped to make this project a success.Ron Jung, instrumentation supervisor for the Golden Giant Mine, spent many hours reviewing process and instrument drawings, selecting instruments and providing hands on support during commissioning.Andy Keough, underground production supervisor for the Golden Giant Mine, was responsible for readying the underground distribution network for paste backfill.H.A. Simons Ltd. personnel who did an excellent job providing sound conceptual and detailed engineering.Fred Brackebusch, of Mine System Design who designed the paste backfill delivery systemPierre Lacombe, mill superintendent of the Louvicourt Mine, generously shared information and operating experience of their paste backfill plant.AbstractThroughout the 11 year history of the Golden Giant Mine, the primary backfilling method made use of consolidated rock fill. New backfill technologies have developed over recent years which now make it possible to use large quantities of fine mill tailings as backfill.In January of 1996, construction began on a new paste backfill plant at the Golden Giant Mine. Six months following, the plant was commissioned. This paper describes the design, commissioning and operational experience to date of the paste backfill plant."

Jan 1, 1997

By M. Massinaei, M. R. Yarahmadi, S. Zeidabadi, M. Oliazadeh

"Although the majority of new flotation column installations continue to be for cleaning or recleaning, an increasing number of flotation projects are specifying columns for roughing or scavenging duties. NICICO has recently installed flotation columns operating in rougher, cleaner and re-cleaner circuits at three new copper concentrators; Miduk, Sungun and Sarcheshmeh. Miduk is probably one of the unique operations that use flotation columns in a rougher circuit. The Miduk rougher circuit comprises five CISA parallel columns. The rougher concentrate constitutes 88% of final concentrate and reports to concentrate thickener. The rougher tailings are scavenged with ten 50 m3 mechanical cells. The scavenger concentrate is then reground and cleaned in three 3.2 m columns in parallel. The cleaner tailings are scavenged in six 50 m37mechanical cells. The cleaner tailings along with the rougher scavenger constitute final tailings.In Sarcheshmeh, the cleaner concentrate is re-cleaned in a column. The column tailings are sent back to the cleaning circuit and the concentrate is reported to the concentrate thickener.This paper reviews performance details of the flotation columns utilized in rougher circuits at Miduk and compares their metallurgical performances in an industrial scale with columns at cleaning circuits for copper flotation. Practical limitations for applying the flotation columns in rougher circuits will be discussed in details.INTRODUCTIONThe use of flotation columns has grown rapidly since the first successful commercial application at Mines Gaspe, where columns were used in a cleaning circuit to float molybdenite. Early applications of columns were restricted to replacing or adding final cleaning stages in existing circuits. Columns can achieve superior cleaning as compared to conventional cells due to their ability to support a large froth depth and the use of water for washing froth. Wash water travels down through the froth and crosses the pulp/froth interface, replaces the entrained particles reporting to the froth from pulp and improve the concentrate grade."

Jan 1, 2011

By Daniel D. M. Adams

Over the last 100 years industry in general has been trying to advance the ability to maintain systems through management processes. Mining has looked to utilize onboard data systems in our mobile mining fleets to compliment these processes. Combining the two concepts build the concept that Rio Tinto refers to as asset health. These programs can generate a cost shift between $20,000 and $100,000 per piece of equipment annually. Even with the documented savings many operations struggle to justify the systems, why?

May 1, 2011

By Bill Almdal

Today?s presentation ? Role of the Regional Issues Working Group ? What does RIWG do? ? How can RIWG?s work benefit Stakeholders? ? Review of forecasts vs. reality ? How have past investment compared to the reality? ? Risks to future growth ? The growth potential is very high and so are the risks ? Examples of outputs ? Housing needs ? Growth in population ? Tires for large trucks The Regional Issues Working Group ? Our vision ? To provide a proactive process which promotes the responsible, sustainable development of resources within the Regional Municipality of Wood Buffalo for the benefit of all stakeholders ? What we do ? Facilitate planning for growth ? Facilitate effective and efficient resolution of issues ? Involve all of the resource developers and affected stakeholders in planning ? Develop plans for sharing benefits with Aboriginal stakeholders ? Benefits for Stakeholders ? Our forecasts include up-to-date information from all developers ? including information on employment and housing needs ? Our forecasts are the basis of planning for many stakeholders ? and can assist in their development planning

May 1, 2002

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 Bern Klein

Motivation for Improved Energy Efficiency in Mining ? Canada potentially adopting Greenhouse Gas Emissions and Intensity Legislation in 2013 ? BC -Climate Action Plan and Energy Conservation Agreement in 2008 ? BC Energy Plan 2007 -BC Hydro is mandated to save 50% of new load growth ? TSM Initiative -Energy Management, Energy Reporting, Setting Energy Targets, GHG Management BC MOU for Energy Conservation Agreement -MEMPR, MABC, BC Hydro

May 1, 2010

By Randy Clarkson

"Free gold particles occur in many base metal and precious metal mines throughout the world. Occasionally mine operators are unaware of the presence of free gold particles in their ores because they have not seen free gold hand specimens or at the working face of the mine.Due to the high density and malleability of gold, large circulating loads of free gold particles can build up over time in grinding circuits. This gold is often deposited in unintended traps throughout the mineral processing system.These unidentified free gold deposits represent a serious security risk as well as inaccessible inventory of gold. Deposits of free gold particles often remain undetected by mine management until they are accidentally discovered while repairing mill equipment. The trapping and subsequent release of gold particles can frustrate attempts to calculate accurate metallurgical balances.Nuclear tracers have been used to determine the free gold recovery efficiency of gravity recovery equipment, drills, and sampling equipment (Clarkson, 1994, 1997, 1998, 1999 and Walsh, 1986, 1992). In 1995, the author used radiotracers to locate and eliminate gold traps at La Mine Doyon (Clarkson, 1997). In 1998 and 2001, the author also salted mineral processing circuits at Royal Oak's Pamour Mine in Timmins (Clarkson, 1999) and at Gold Corp’s Red Lake Mine in Ontario with radioactive gold particles.The gamma and X-ray radiation from gold's nuclear isotope (Au198) were detected through steel, in pipes, and in moving equipment with scintillometers. The radiotracers proved to be a safe, rapid and accurate method of identifying gold traps, improving security, determining the recovery efficiency of Knelson gold concentrators and estimating retention times of gold particles in various processes."

Jan 1, 2003

By P. H. Agson Gani, T. Sitorus, N. P. Widodo

"PT ANTAM UBPE Pongkor underground mine use blasting to develop its tunnels which will cause poisonous and dangerous gases trapped inside mine. To analyze this case, a study of mine ventilation, the dispersion of carbon monoxide (CO) gas concentration and diffusion coefficient is commenced. At the end, the re-entry time formula will be determined. Results indicate that this study is site specific and could only be applied in the place this study executed. The aim of this study is to be further developed by applying Principal Component Analysis (PCA) to find a universal re-entry formula. KEYWORDS Mine Ventilation, Re-Entry, Smoke Clearing, Diffusion Coefficient, Carbon Monoxide Gas, Gas Dispersion INTRODUCTION Pongkor underground mine is using cut and fill as its mining method. Thus, its development and production processes require blasting to develop its tunnel. This process caused poisonous and dangerous gases spread and trapped inside the mine, one of them is carbon monoxide (CO) gas. CO is formed in an unbalanced reaction of explosives detonation and could be the cause of headache, blackout and death to people who inhale CO at certain concentration (McPherson, 2011; Hartman, Mutmansky, Ramani, & Wang, 2012). Mine ventilation system is installed in the mine to resolve this problem. Mine ventilation play an important role to disperse CO gas by absorb the poisonous/dangerous gases and deliver clean air into mine. The important parameter is diffusion coefficient, because diffusion is affecting particulates or gasses spreading from its sources throughout the mine. Diffusion coefficient is the total diffusion in axial direction of turbulent flow mainly by convection of bulk motion, advection and eddy diffusion, while the effect of molecular diffusion is appreciably negligible (Widiatmojo et al, 2015). Taylor (1953, 1954) develops a theory about the dispersion by inducing a slow stream of solvent into a capillary tube. Taylor used Reynolds assumption of radial diffusivity to be analogous with the transfer of the matter in turbulent flow as well as the transfer of momentum and heat. Then, Taylor proposed the formula of diffusion coefficient, D (m2/s), against pipe diameter and turbulent shear velocity are as follow:"

Jan 1, 2019

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 B. S. Fee, R. R. Klimpel

"Froth flotation is the most widely used and economic means of concentrating metal sulfide ores such as those containing copper, lead, zinc, nickel, molybdenum, and pyrite. Also recoverable are other metal species that are often associated with sulfide ores such as cobalt, platinum, gold, silver, etc. Most of the initial developments made with the process of froth flotation in the early 20th century were based on the processing of metal sulfide ores. It is the relative technical and economic ease of floating metal sulfide minerals with small amounts of appropriate frothers and sulfur containing (thio) collectors that has been a major economic driving force behind the rapid expansion in the supply of metals such as copper, lead, zinc, and nickel that has occurred in the world's economy in the last 50 years. This author estimates that 1.6 billion tons of sulfide ores are processed each year (1980) in the free world based on the froth flotation process.While there has been a tendency for the quality of metal sulfide ores in any one geographic location to deteriorate over time due to mining intensity, the overall global supply of sulfide minerals is still very large. Thus, the physical supply side of sulfide ore concentrates has not been under strong technology improvement pressure with increasing metal demands. Part of this is due to the ability of capital to consistently move to new geographic locations having suitable grade sulfide ores. In these moves, the actual froth flotation technology used (including collector chemicals) has had to change little. As an illustration of this trend, of the approximately 80,000 metric tons of thio collectors used commercially (1980) in the free world, almost 98% were known and manufactured in some form 25 years ago (1). This is clearly not typical of reagent development in other process related industries. In addition, the industrial scale practice of froth flotation applied to sulfide ores has proceeded since the 1920 s with often little direct (predictive) scientific explanation due to the extreme complexity of the flotation process. Empirical testing has been a mainstay of industrial flotation reagent development and use. Even today there is often strong disagreement between researchers as to the mechanisms of chemical flotation practices that have been performed successfully at an industrial scale for many years."

Jan 1, 1987

By Jesse L. Duke

Outline ?Understanding the context ?The Business, political, social and legal environment ?Recipes for Success (three Ps) ?Develop effective Partnerships/relationships ?Plan carefully ?Actively Manage the ?Process? Business Environment ?Nunavut?Impressive mineral potential ?Emerging diamond industry ?Dominated by Juniors ?NWT ?Maturing Diamond industry ?Emerging oil and gas industry ?Yukon ?Alaska Highway Pipeline ?Junior-dominated exploration and development ?Growing acknowledgement in Canada of the importance of northern resources ?Shift of thinking: north-south infrastructure (vs. East-west)

May 1, 2006

By Catalin Florin Petre, Elahe Ghasemian Langeroudi, Abdelaaziz Azizi, Éric Proulx, Caroline Olsen, Paul Blatter, Faïçal Larachi, Claude Gagnon

"The recovery of gold from ores is often accompanied by the release of other species in the leach solution. This state of affairs leads to depleted free cyanide levels in the slurry. Therefore, separation and quantification of these cyanicides and free cyanide at different stages of the cyanidation process as well as in waste solutions is crucial to provide mitigation tools by preventing leaching of deleterious metals for environmental considerations.COREM and the research group of Prof. Larachi have been working together on the control of gold passivation and cyanicides during cyanidation for several years. Previously, a first capillary electrophoresis (CE) protocol for the speciation of sulfur and cyanicides (SCN-, Cu, Fe) during cyanidation of gold complex sulfide ores was developed and validated for assessing industrial process water.The separation of zinc cyanide complexes used to be confronted with a number of difficulties due to the weak and/or undetectable cyanocomplexes in formally available CE protocols. Moreover, according to our knowledge, no direct CE protocol exists to separate free cyanide. Therefore, a new study aimed at developing a second CE protocol for the detection and quantification of cyanide complexes of zinc and nickel as well as of free cyanide in the cyanidation process water.To achieve this goal, six common carrier electrolytes such as pyridine, trimellitic acid, 4-methylbenzylamine, sodium chromate, phthalic acid and tris base were studied, using an indirect UV detection method. The best results were obtained using sodium chromate for which all ions were successfully separated and quantified. In addition, the effect of electric field strength, injection volume, electro-osmotic flow (EOF) modifier and background electrolyte (BGE) concentration were examined, while peak height, peak area and noise were considered for optimization.As a result, the new protocol is expected to complete the initial CE protocol by detecting cyanide complexes of zinc and nickel as well as free cyanide. Moreover, analytical determination of free cyanide in the presence of weak cyanide complexes achieved by the new protocol was also compared to conventional titration using silver nitrate solution. This new CE protocol will contribute to applied research and help plants to better understand and eventually control the behaviour of cyanidation circuits."

Jan 1, 2011

By G. Naud, J. Robitaille, M. Buonvino, A. Veltmeyer, A. R. Laplante

"A B6 Falcon concentrator was tested on several systems: a synthetic magnetite-silica ore, a massive sulphide gold-copper ore, a fine gold-pyrite-silica flotation tail, and a high grade gold ore in a low sulphide gangue (cyclone overflow).The Falcon demonstrated its ability to achieve separation in all cases, but with varying degrees of success. For the magnetite-silica system, separation proceeds until the concentrate bed overloads, at a mass of 300 to 400 g of magnetite. Recovery increased with decreasing particle size, down to the 25-37 µm and in some cases even the -25 µm class. Bowl geometry (angle) and gangue size distribution were the most significant operating variables. Results with the massive sulphide ore were the poorest, with gold recoveries typically around 10 to 20% at very low upgrading ratios, 1: 1 to 5: I. Gold recovery from the fine flotation tail ranged from 30 to 70% at upgrading ratios of 5 to 15; actual plant application would require a continuous unit (Falcon C20). The high grade gold cyclone overflow yielded a wide range of gold recoveries, but a very consistent relationship between recovery and mass processed. A concentrate of 0.5% Au could be processed at a recovery of 50%.The paper also presents results of a C20 application to recover fine iron from a magnetic tail. The unit is capable of recovering approximately 70% of the fine liberated iron in a high density product, with modest upgrading below 105 µm, and virtually complete rejection of the + 300 µ m product."

Jan 1, 1993

By T. Backers

In fracture mechanics modeling the rock mass is seen as the combination of rock material and fractures, which are evident on different scales. The activation and propagation of fractures dominates the stability and performance issues as well as fluid flow potential. Once fractures have started to grow into each other and create through going separations, stability of rock engineering constructions may be violated. Further, as fracture mechanics inherently incorporated a scaling law in the form of the participating fracture length, scaling issues can be more accurately mirrored. This contribution highlights some examples of application of a fracture mechanics based code on some rock mechanics issues such as numerical laboratory experiments, borehole stability or the creation of fluid pathways due to underground constructions. The results show explicitly the creation of fractures and connection of existing ones, and hence the safety and performance issues. It has to be concluded that the basis for frequent application of fracture mechanics on specialized challenges in Geomechanics is laid, and the needs for future developments are defined.

May 1, 2009

By Mike Turner

The Otter-Juan mine was closed by WMC Resources? Kambalda Nickel Operations (WMC-KNO) in 1999 due to the combined effects of low Nickel prices and high mining costs. GBF Mining Pty Ltd purchased Otter-Juan Mine from WMC in early 2001 as part of WMC?s disinvestment from the nickel mines in the Kambalda area. Goldfields Mine Management (GMM), (a wholly owned subsidiary of GBF Pty Ltd) re-opened Otter-Juan in May 2001. The Otter-Juan mine is one of the oldest mines in the Kambalda region and is now mining at depths below 1160mbs. Stresses are very high, rock mass deformation considerable, and the mine has a history of serious seismic activity. Orebody widths in the current mining area range from 2 to 2.5m, with dips from 25° to 40°. On taking over the operation, GMM converted the mining method from the previous mechanised drift and fill method to a slot-rise and strip method using hand held airlegs. During the latter years of production under the control of WMC, production averaged around 12000 tonnes per month, with grades of 2.7% and orebody extraction of only 55 to 60%. In the last three years of operation under the control of GMM the mine has produced an average of 12000 tonnes per month of ore at an average grade of 4.2% and with an orebody extraction of 70 to 75%. The mine is now highly profitable with at least another 3 years of reserves remaining at depth. The main benefits of the current method include reduced dilution and increased extraction. In the relatively poor ground conditions experienced this has only been possible using airleg mining, with excavations designed to suit conditions, support to suit rockmass deformations, and with improved extraction sequencing. Other benefits have included improved operating conditions, reduced falls of ground incidents and a dramatic reduction in seismic activity. These achievements have only been possible by stepping back in time and using traditional airleg stoping methods to extract the maximum amount of the orebody with minimum dilution. This paper includes details of the mine history, geology, mining method, seismicity, and support.

May 1, 2004

By C. O?Connor

With ever-increasing global demand for mineral resources, numerous mines are moving towards developing and mining deeper, more complex and lower grade ore bodies. In many cases, mass mining methods (e.g. block caving) are being considered to deal with deeper, lower grade deposits. The body of practical knowledge, however, related to the impacts mass mining methods have on the surface environment in terms of rock mass response, subsidence, etc., is limited, imposing both economic risks to the mine and safety risks to mine personnel. This paper presents the framework for and preliminary results from a large collaborative research initiative between Diavik Diamond Mines, Rio Tinto, the University of British Columbia (UBC) and Simon Fraser University (SFU). The project involves the integration of available subsidence, rock mass, mine operation and monitoring data, together with the advanced application of combined finite/discrete-element modelling codes capable of simulating fracture behaviour, cave propagation and surface subsidence above block cave mines. The main objective of this work is to develop advanced numerical modelling methods to characterize complex rock mass behaviour above block cave mines. The research will also include the study of rock deformation mechanisms associated with the transition from surface to underground mining and the potential interaction between simultaneous open-pit and underground mining operations.

May 1, 2007

By P. T. O'Kane

"INTRODUCTION Wright Engineers Limited is active and has extensive experience in the design of pressure oxidation plants for the treatment of refractory gold ore and concentrate. In addition to the Mercur oxidation facility, similar projects undertaken during the last few years include the 3000 ton per day acid oxidation plant for the Getchell Mine, Nevada, a concentrate treatment autoclave for Asamera in 1984 and a feasibility study of a 50-tons per day autoclave plant for Consolidated Professor's Duport property in Ontario. The Equity Silver antimony and arsenic precipitation autoclaves, and the low pressure autoclaves at Key Lake Uranium in Northern Saskatchewan were also engineered by Wright in recent years.In August 1986, Wright was retained by Barrick Resources (U.S.A.) Inc. to add a 750 tpd pressure oxidation circuit to the existing mill at their Mercur Gold Mine, Utah. This paper describes this facility and outlines the start up in the spring of 1988 and subsequent successful operation. MERCUR OPERATION The Barrick Mercur Gold Mine is located at the south end of the Oquirrh Mountains in Tooele County, Utah. The carbon-in-leach (CIL) process plant camnenced operation in 1983 with a design throughput of 3000 tpd and has since been expanded to handle rrore than 5000 tpd. 'IWo ore types are mined, an oxide ore and a refractory ore, which is by Barrick's definition ""an ore from which less than 60% gold extraction is achieved by a standard CIL amenability test."" Typical of many sulphidic/carbonaceous ores, the refractory gold does not respond well to the cyanidation process. As a result, refractory ore has been stockpiled since the start of mining. As of June 1987, Mercur had about 570,000 tons of refractory ore stockpiled and 5.7 million tons of proven and probable reserves, grading 0.06 oz/t including approximately 3.5 million tons of tailings from the previous operation grading 0.55 oz/t. In 1986, Barrick decided to build a 750 ton per day pressure oxidation plant to process these ores. The process, for which a patent was granted, comprises pressure oxidation of the sulphides in an alkaline environment. It was developed in 1981 but was set aside in preference of a CIL plant treating only oxide ores by the previous owner of the property, Getty Oil. This process is capable of increasing gold recovery from the refractory ore from as low as 35% by conventional CIL processing to more than 85%. In 1986 Wright Engineers was engaged to undertake a feasibility study based on batch testing. This lead to a decision by Barrick Mercur later that year to build the commercial pressure oxidation plant. Wright was awarded the contract for engineering, procurement, construction managernent and commissioning in March 1987. The plant was mechanically complete in January 28, 1988, and was in operation by February 1988."

Jan 1, 1989

By Jean-Sébastien Kroll-Rabotin, Éric Climent, Florent Bourgeois

"Falcon concentrators are enhanced gravity separators designed for concentrating fine and ultrafine slurries. The Falcon UF model is unique in that it is dedicated to beneficiation of ultrafines, one key feature being that it does not make use of any fluidisation water. In a former study, we investigated the physical mechanisms that govern the transport of ultrafine particles (in the range 10 to 80 µm) inside Falcon UF concentrators, and concluded that separation efficiency is governed by differential settling. Initially, we derived and published a predictive model of the partition function under dilute conditions. The present paper proposes an extension of the initial model to concentrated ultrafine suspensions for application to industrial scenarios. The paper discusses how hindered settling has been added into the initial model to account for solid concentration effects. The modified model is tested against experiments carried out with a laboratory scale UF Falcon concentrator from dilute conditions up to 30 vol%. A good agreement between measurements and model predictions is obtained, which confirms that our hypotheses about the physics of separation inside a UF Falcon separator remain valid even at high concentrations.INTRODUCTIONThe Falcon concentrator is a fast spinning bowl that is fed at its centre of rotation. It uses centrifugal force to separate particles that are transported inside a thin liquid film that flows upward along the inclined wall of the bowl (McAlister and Armstrong, 1998). Due to differential settling, dense and coarse particles are concentrated inside the bowl whereas light and fine particles are rejected with the overflow stream. The fast rotation speed of the bowl yields high centrifugal force several hundred times the attraction of Earth. Despite the thinness of the liquid film (between 100 µm and 1 mm with a Falcon L40) where separation takes place, the Falcon concentrator can treat high flowrates (up to 30 L/min). At the bottom of the bowl, an impeller transmits the bowl rotation to the feed, which drains upward by centrifugal force as soon as it hits the base of the spinning bowl (Figure 1)."

Jan 1, 2011

Ontario Operaations Mining Garson Stobie Copper Cliff North Copper Cliff South Creighton Mcreedy East Milling Clarabelle Mill Smelting Smelter Matte Processing Anode Casting Refining Copper Cliff Nickel Refinery Port Colborne Cobalt Refinery

May 1, 2007

By Pierre Lacombe

"The operation of the Louvicourt Mine will have to rely on stringent grade control and on the optimization of the amount of blocked ore made available per given development effort. All of the above being necessary to obtain the highest throughput at the lowest mining cost.To assist in achieving these objectives, the need for production of a competent fill with short curing time was recognized early by the project partners. As well, operating costs associated with the selected method should be as low as possible while meeting the technical criteria.A feasibility study comparing filling methods showed potential benefits in all aspects of the paste fill use, except for its higher capital costs and increased operational complexity. This last consideration was tackled by the conservative design approach adopted in the flowsheet development of the paste fill plant.Since commissioning of the plant has just been completed at this time, the paper will focus on the feasibility study and its background, the design of the plant and testwork results at pilot plant and plant scale.RésuméLe succès de l 'opération de Louvicourt Mine dépendra d' un contrôle serré des teneurs du minerai et de la maximisation de la quantité de minerai développée par effort uni ta ire. Ces critères devant etre respectés afin d'obtenir le taux de production le plus élevé au coût le plus bas.De façon à satisfaire ces contraintes, les partenaires du projet ont reconnu tôt la nécessité de produire un remblai de qualité tout en maintenant un temps de curage court. De plus, les coût d'opération associés a cette opération se devaient d'être des plus avantageux sans sacrifier l'atteinte des objectifs techniques.Une étude de faisabilité comparant différentes méthodes de remblayage a démontré que le remblai en pâte offre des aspects positifs sous taus les angles, si ce n'est de son coût en capital initial élevé et de sa complexité relative d'opération. Ce dernier point fut considéré de près par l'adoption d' une approche conservatrice lors de la conception de l'usine de rernblai.Puisque la mise en service de l'usine n'a été faite que les détails de l 'étude de faisabilité et ses fondements, 1 'usine et des résultats d' essais obtenus a l'échelle de l'usine seront discutés."

Jan 1, 1995