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By J. P. Mogan, E. D. Dainty, A. Lawson

"The toxicity reduction of emissions from two diesel engines by the emulsification of water into fuel oil was investigated to determine the applicability of such systems to underground mining machinery. . The engines studied were: 1) the Deut; F6L7J4, four-stroke, air-cooled, 6-cylinder, V-configuration, indirect-injection (IDl) engine, and 2) the Detroit Deisel Allison Division 8V7JN, two-stroke, water-cooled, 8-cylinder, V-configuration, direct-injection (Dl) engine.The application of emulsified fuel treatment to the two-stroke engine did not prove to be practicable. In the case of the Deutz engine, however, substantial benefit resulted. For a modest J5 per cent water content in the fuel and an injection timing of24° BTDC, approximate reductions of40 per cent in the concentrations of both particulate matter and nitric oxide (NO) were produced. These reductions were accompanied by insignificant changes in other toxic constituents. The net result was an approximate 30 per cent reduction in the over-all exhaust toxicity for typical LHD operation as assessed by the Health Effects Index criterion. This toxicity reduction represents a significant advance from the points of view of an improved underground environment and/or reduced ventilation costs."

Jan 1, 1981

By Paul Laframboise, Nigel MacDonald, Mike Hallewell, Robert Thorpe

"Galmoy Mine, owned by Arcon Mines Limited, has operated since 1997, and is one of three operating lead/zinc mines in Ireland. Changes in ore type starting in mid 2002 created challenges to metallurgical operations at Galmoy. This resulted in unacceptable lead and zinc flotation performance, which prompted initiation of a formal plant review and a subsequent stabilization programme. This involved a structured review of operational practices, development of a new Standard Operating Procedure (SOP) which in turn led to significant changes in process control equipment needs in conjunction with extension of zinc flotation cell residence time.This paper will describe the metallurgy of the Galmoy operation. Reasons for the poor metallurgy experienced in 2002 will be described, as well as the solutions identified to overcome these problems. By the second quarter of 2003, these solutions had been implemented and recoveries had risen to record levels.INTRODUCTIONGeneralGalmoy Concentrator is located in County Kilkenny (Refer to Figure 1 below) and was constructed during 1996 and commissioned in 1997.The concentrator at Galmoy had been designed initially to treat 650,000 tonnes per annum of primarily CW ore type. The main mineral of economic significance was sphalerite (Typically 10 to 11% Zn) with some minor galena (0.7%Pb) in a dolomite (Magnesium Carbonate) host rock.The only other competing sulphide mineral was pyrite (Circa 3 to 5% Fe in Mill Feed. This CW ore type predominated the first 6 years of production, but in August 2002, the ore mineralogy changed due to significantly higher levels of pyrite rich G ore body being blended in with CW ore."

Jan 1, 2005

By T. Warren, R. Pender

"Significant strides have been made during the past decade to integrate the traditionally separate administrative functions of financial management, materials management and maintenance management.In 1983, Key Lake Mining Corporation (KLMC) brought on-stream one of the most technologically advanced mining operations in North America. There was a requirement to support this new facility with state-of-the-art management information systems.This paper will discuss the development and evolution of the corporation's computerized information systems with specific emphasis on the utilization of computer systems to assist maintenance personnel in performing their work activities:Note: In August of 1989, the administration and operation of the Key Lake Mine was assumed by CAMECO - A Canadian Mining and Energy Corporation.IntroductionThe Key Lake Mining Corporation was incorporated in 1979 and operates a $500 million uranium mining and milling complex located in northern Saskatchewan.The feasibility study and environmental impact statements for the Key Lake Mine were submitted in 1979and in August of 1981, following a public inquiry, approval to proceed with construction was granted. Ore processing commenced in October of 1983 and during 1984 a total of 10.4 million pounds of uranium oxide (U3O8) was produced. In 1987, an annual production of 13.5 million pounds was achieved clearly establishing Key Lake Mining Corporation as the world's leading producer of uranium oxide. Current ore resources are expected to extend production of the Key Lake facility into the year 2000."

Jan 1, 1990

By M. Ataee-pour, S. E. Jalali

So far, a large number of algorithms have been developed for the optimization of pit limits, most of which follow deterministic rules. In this paper, a new algorithm is introduced, which follows a probabilistic logic using the Markov chain process. The algorithm is implemented on a transition matrix that corresponds to the 2D conventional economic block model of the mining area. The probability of mining a block is proportional to the desirability it may provide. Applying this algorithm, the probability of mining each block is obtained, and finally, the optimum pit limits are defined as the pit, which provides the highest probability of mining. In order to validate the proposed model, a numerical example is given and the results of the algorithm are compared to those of a dynamic programming algorithm. A 2D analysis of the problem is discussed in this paper. Although dealing with 3D problems requires larger size matrices, the optimization method is the same and the algorithm does not need any smoothing.

Jan 1, 2006

By P. J. Gron

"The Samatosum Project is a base and precious metal deposit located in south central British Columbia. A dilute ore reserve of 766, 682 tonnes grading an average 1.1% copper, 3.0% zinc, 1.4% lead, 833 gram per tonne silver and 1.6 gram per tonne gold is available. The base metals occur as tetrahedrite, chalcopyrite, sphalerite and galena. Virtually all of the silver and gold are associated with the tetrahedrite.The mill is operated at a rate of 21 tonnes per hour. Sulphur dioxide is used as a zinc depressant in the grinding circuit. Production of a Cu/Pb/Ag concentrate is accomplished by conventional flotation. This concentrate is then separated into Cu-Ag and Pb concentrates through a reverse flotation circuit utilizing sulphur dioxide, starch and sulphuric acid as lead depressants.The tailings from the Cu/Pb/Ag circuit are treated with copper sulphate to activate the zinc. Production of a zinc concentrate is accomplished by conventional flotation. Dewatering of the concentrates to 6% moisture is done with a LAROX filter press.Tailings effluent is treated with lime and sodium sulphide to precipitate out the heavy metals. The resulting sludge is treated in OYNASAND sand filtration units to produce a quality effluent."

Jan 1, 1990

By D. B. Felsher

"Lakeshore Gold’s Bell Creek Mill is located in Timmins, Ontario. The mill has been in operation since 2009 and has undergone several small expansions since then. In 2012 - 2013 the first major mill expansion was commissioned raising the mill capacity from 2,000tpd to 3,150tpd. This was done through the installation of a new ROM ore truck dumping facility, jaw crusher, ore storage dome, SAG mill, leach tank, CIL tank, and electrowinning cell. This paper will cover the equipment installed to raise the tonnage as well as the commissioning of the new equipment including problems encountered and how these problems were solved.IntroductionLake Shore Gold acquired the Bell Creek Mill, along with the Bell Creek Mine, from the Porcupine Gold Mines Joint Venture, a joint venture between Goldcorp Canada Ltd. and Kinross Gold Corporation, in December 2007.The Bell Creek mill, which processed ore from the Bell Creek Mine has consistently achieved recoveries of over 95%, is a conventional gold mill circuit, involving crushing and two stage ball mill grinding, gravity and leaching, followed by Carbon-In-Pulp (CIP) process for gold recovery. The facility had been placed on care and maintenance in 2002. At the beginning of 2009, the mill had been refurbished with an initial capacity of 800 tonnes per day and was subsequently refurbished to a capacity of 1,500 tonnes per day near the end of the third quarter of that year. The Mill was then expanded in 2010 to a capacity of 2,000 tonnes per day.In late 2011, the Company commenced a 50% expansion of its milling facility, from a processing capacity of 2,000 tonnes per day to 3,150 tonnes per day. Phase 1 of the expansion, which mainly involved enhancements to the solution circuit (“back end”) and increased the mill’s capacity to 2,500 tonnes per day, was completed at the end of 2012. Commissioning of Phase 2 of the expansion, to a capacity of 3,150 tonnes per day, commenced at the end of July 2013."

Jan 1, 2015

By P. J. Mehrfert

"Recovery of mineralized coarse particles is notoriously low in conventional concentrators that treat copper porphyry ores. The application of coarse particle flotation techniques has the potential to achieve comparable metallurgical performance at significantly coarser primary grind sizings. ALS Metallurgy has been conducting both internal research and commercial test programs to investigate the potential of Eriez HydroFloatTM technology on copper sulphide ores. Test data indicates that significant improvements in the recovery of copper sulphide bearing particles between 200µm to 850µm can be achieved using Hydrofloat technology compared to conventional flotation techniques. This paper summarizes the results from a selection of test programs that includes recovery by size data from both conventional flotation and HydroFloatTM tests. An explanation of the apparatus and test procedure will be given. Mineralogical analyses of the test products and characteristics that limit metallurgical performance will be discussed.Description of Apparatus and Test ProtocolThe HydroFloatTM laboratory cell is a clear plastic column with an internal diameter of 14 cm. Water and air are introduced to the cell through a circular manifold located in the lower portion of the cell. The cell has a conical bottom which directs slurry to a pinch valve that controls the discharge of tailings. Feed solids are introduced to the upper portion of the cell in slurry form. The cell is operated in a manner such that the manifold water creates a teeter bed zone of suspended solids in the middle portion of the cell. Tailings exit the bottom of the cell at a high pulp density, and most of the introduced water overflows the top of the column and is collected in a launder. Particles with a hydrophobic surface may attach to air bubbles that percolate through the teeter bed, rendering them sufficiently buoyant to be transported to the overflow launder.Three significant features of this arrangement enhance the potential to recover coarse, low grade particles by flotation techniques. Firstly, the hindered settling conditions created by the rising column of water allow coarse particles to become buoyant once attached to a modest sized air bubble. Secondly, the flow conditions within the cell are relatively quiescent compared to a conventional flotation cell that utilizes an agitator. This allows particles that have limited hydrophobic portions of their surface, due to a low content of exposed sulphide mineral, to maintain a somewhat fragile attachment to air bubbles long enough for successful recovery to the overflow. Finally, the absence of a froth phase at the top of the cell allows particles attached to air bubbles to immediately exit the vessel, reducing the potential to drop back into the pulp phase as bubbles burst or coalesce."

Jan 1, 2017

By N. Coli

The exhausted Santa Barbara open pit mine (Tuscany, Italy), owned by the main electric power company in Italy (ENEL S.p.A,) extracted lignite as a fuel for the Santa Barbara thermoelectric power plant. The mining activity led to the excavation of a wide slope (with maximum height of 200 m and a planar extension of about 1300 m x 500 m) in the Shale Limestone Chaotic Complex (SLCC) (Figure 1). Since the beginning of its excavation the slope underwent rotational landslides and diffuse instability phenomena. From a geotechnical point of view the SLCC represents a typical bimrock (block-in-matrix rock) (Medley 1994, Medley 2002, Medley 2007) characterized by a mixture of a highly sheared, scaly-fabric, clayey matrix and calcareous blocks ranging from a few millimetres to tens of metres in size. Since the geometrical properties of blocks (grain-size distribution, shape, orientation and volumetric proportion) have been proved to influence the mechanical behaviour of bimrocks (Lindquist & Goodman 1994, Goodman & Ahlgren 2000, Kim et al. 2004, Sonmez et al. 2006), the aim of the present study is to investigate the geometrical properties of calcareous blocks in order to properly characterize the mechanical behaviour of the SLCC bimrock and to further assess the stability of the slope. Block size-distribution and shape were investigated by means of advanced image analysis techniques of SLCC pictures taken in the field. Geostatistical semivariograms and variographic maps were also used in order to investigate the anisotropy of block spatial distribution. Finally, in-situ large sized sieving tests were carried out to investigate the volumetric block proportion within the clayey matrix.

May 1, 2009

Scope / Agenda ? What is Situation Awareness (SA)? ? Background on SA theory ? SA is critical in a wide variety of domains ? SA and human performance ? Consequences of poor SA ? Significant challenges for SA in mining operations ? Technology centric design ? SA-oriented design methodology ? Goal-Directed Task Analysis ? Design ? SA Measurement and Evaluation ? Applications of SA-oriented design

Aug 1, 2013

By F. D. Ford, Z. Dai, A. Byers

Manitoba Mining and Milling operations consist of three underground mines (Thompson T1, T3 and Birchtree), feeding the Thompson Mill. Three years ago, a collaborative effort involving Mines Exploration, Mines Project Development Group, Mill Technical Services and Vale Base Metals Technical Excellence Center was initiated to establish and verify the cause of high variability in concentrate quality and Ni recovery at the Thompson Mill. One outcome of this work was a program to systematically characterize the mineralogy and metallurgical performance of current and future orebodies feeding the mill. Mineralogy results show that high value enabling ores typically have a high pentlandite to pyrrhotite ratio and benign silicate mineralogy (mostly quartz and feldspar from sedimentary host rocks), while metallurgically challenging ores contain some combination of pyrite and/or hexagonal (non-magnetic) pyrrhotite and/or elevated quantities of talc (with associated carbonates) derived from altered ultramafic host rocks. The metallurgical performance of these two ore types has been simulated by an Excel particle flotation model, which calculates the relative floatability of particles based on the particle’s mineral composition and mineral locking determined from MLA images. The relationship between these mineral properties measured by MLA and metallurgical performance was established using 13 monthly composite samples from Thompson Mill. The model was then validated with results of laboratory flotation experiments on individual orebodies submitted for evaluation. The validated model can be used to predict plant metallurgical performance based on individual ore bodies feeding the mill. Individual orebody’s grade-recovery curves are assumed to be additive, and can be weighted in proportion to the mill feed to predict mill recovery over the same time period. The ore mixing can be done with a simple Excel spreadsheet and comes with a graphical output for easy visualization of the resulting grade-recovery curve.

Jan 1, 2015

By Paul J. Sylvester, Yeonuk Choi, Mike Nelson, Louis J. Cabri, Mike Tubrett

"The development and characterization of sulphide standards containing as many as seven precious metals has increased the efficiency and comprehensiveness of micro-analyses for deportment studies using laser ablation microprobe inductively coupled plasma mass spectrometry (LAM-ICPMS). Because trace precious metals occurring in solid solution or as sub-micron inclusions in sulphides, arsenides, and sulpharsenides are often heterogeneously distributed, a significantly large number of analyses are required. Using well-prepared samples it is possible for up to 120 analyses per day, far more than by other comparable methods. Examples will be discussed from projects focused on the deportment of Au and the platinum group elements (PGE).INTRODUCTIONBecause gold and the platinum-group elements (PGE) occur as both discrete minerals and in trace quantities in a variety of minerals (mostly sulphide, arsenide, and sulpharsenide minerals), specialized trace analytical methods were developed and applied to determine the deportment of precious metals in ore deposits, requiring sensitivities ranging originally from about hundreds to presently tens of ppb for individual precious metal or less.In mineralogical studies, micro-analytical techniques such as the electron microprobe were first applied to obtain analyses for major elements in about 1959-60, but as the instrumentation improved early attempts for PGE in potential carrier minerals indicated that reasonable levels of detection (LOD) were of the order of 300-400 ppm, depending on analytical conditions, X-ray spectral lines, and mineral matrix (e.g., Cabri and Laflamme, 1976). Eventually, the lowest detection levels by electron probe micro-analyses (EPMA) obtained for some PGE were of the order of 10s of ppm using high accelerating voltage and current for extended measuring time on peak and background (Gervilla, Cabri, Kojonen, Oberthür, Weiser, Johanson, Sie, Campbell, Teesdale and Laflamme, 2004)."

Jan 1, 2010

By David R. Skuse, Jacek A. Kostuch, Steven M. Fortier

"Particulate ground calcium carbonate (GCC) is used as a filler and coating pigment in a wide range of applications including papers, paints, plastics and films. In this paper we will overview the requirements for GCC used in both filling and coating applications in the paper industry and highlight the processes used in the production of these materials.INTRODUCTIONCalcium carbonate is both abundant and very widely distributed occurring most commonly as limestone, marble and chalk (Harben 2002). Given, the high purity, whiteness and relative inertness of these materials it is not surprising that they are heavily utilised in a range of industrial applications. Worldwide ground calcium carbonate (GCC) capacity is estimated at 50.5 million tonnes per year (Roskill, 2002). This usage is divided between relatively coarse materials that are used in applications such as landscaping, cultured marble and carpet backing and finer grades that find application in plastics, rubbers, inks, paints and paper. Given the usage of calcium carbonate products across a very wide range of consumer products, the outlook for GCC is very promising with growth expected in many markets. Growth is anticipated across many applications in the emerging nations and more specifically in paper applications on a global basis.Over the last several decades the GCC processing industry has evolved to be well adapted to both the cost effective production and delivery of standard products and the production of high performance speciality products. Many of the standard unit operations found in the metaliferous raw material processing industry are also used, albeit in some cases in modified form, in the processing of GCC. Coarse products (diameter > 3 - 10 µm) are typically produced by dry processing routes. Whereas, the finer products are typically produced by a combination of wet and dry processing."

Jan 1, 2004

By J. R. Kadambi, E. Kucukal, J. Furlan

"Hydrocyclone separators are used in various industrial applications, including mining milling and tailings systems, in order to separate or classify solid particles and liquid droplets from multiphase systems. The flow within a hydrocyclone commonly used in the mineral processing industry was investigated numerically and experimentally using Particle Image Velocimetry (PIV) and refractive index matching techniques. The computational simulations were performed using a commercially available CFD package, STAR CCM+. Two turbulence models were used in the numerical calculations: the k-? model and the Reynolds Stress Model (RSM). In both cases, the first order discretization scheme was unable to resolve the flow characteristics accurately due to the high levels of numerical dissipation. PIV measurements were taken at various spatial locations along the cyclone. Both the numerical simulations and PIV data demonstrate that tangential velocities tend to increase when going radially inward from the cyclone wall towards the vortex finder, and reach a maximum value before they begin to decline rapidly and eventually become zero at the wall. The results also demonstrate the utility of non-axisymmetric approaches in cyclone flow simulations for a greater understanding of the fluid mechanics. The computational results were validated globally using pressure and flow rate readings at the boundaries and locally by comparison to the PIV velocity vector maps and profiles. The comparisons demonstrated good agreement between the two models.IntroductionHydrocyclones are devices used to separate and classify solid particles or liquid droplets from liquid-solid or liquid-liquid systems. Versatile in application, they have been widely used in many industrial applications including the food, oil, power generation, chemical and mineral processing industries since 1891, when the first hydrocyclone was introduced by Bretney (Park, 2003). Hydrocyclones have a relatively simple design with no moving parts, which leads to an efficient separation process."

Jan 1, 2016

By John Kazakoff, Andrew Mortimore

"Production at the remote Kumtor Gold Mine in Kyrgyzstan commenced on schedule in December 1996.The ore mined during the first few months of 1997 from the upper benches of the pit did not produce the results predicted by the feasibility study. Low metallurgical recoveries experienced at the time were cause for great concern.It soon became clear the recovery difficulties centred around the preg robbing nature of the ore.Procedures were developed to selectively stockpile highly carbonaceous low recovery ore types. Testing methods were developed in the mill to quante the preg robbing activity of the ore. Preg robbing masking agents were added to the process to reduce the preg robbing activity of the ore.The importance of coconut carbon activity relative to the preg robbing activity of the ore was realized. Every aspect of the performance of coconut carbon in circuit was evaluated and optimized to improve carbon activity.Mineralogical analyses were completed defining the deportment of gold in ore and process tailingsBy year end the recovery difficulties had been overcome and plant design production had been achieved. Process improvements continue through 1998."

Jan 1, 1999

By K. Ananthanarayanan, R. I. L. Guthrie, S. A. Argyropoulos

"The low cost and availability of micro-computers and their peripherals provides the metallurgical engineer with the opportunity to use such computers in a wide variety of applications. In this paper, the authors describe the development of a low cost data acquisition system capable of measuring up to 8 analogue channels at a sampling rate of up to 5000 measure mentsper second. This system is equipped with proper hardware and software so that the micro-computer can be linked to a central computer facility such as the McGill System for Interactive Computing (MUSIC). This central computer facility is supported by an AMDAHL V7 computer. Using the present interface, communication rates between the microcomputer and the central computing facility can be as high as 9600 (baud).The above mentioned data acquisition system is currently used for monitoring dissolution kinetics of ferro-alloy additions in liquid steel. In addition to this, special software has been developed which enables the user of this system to monitor solidification rates of ingots, etc. As economic considerations are always important, comparisons have been made with existing recorders which show that the cost Of the present system is only 30 per cent more than a two-pen strip chart recorder.RESUMELa disponibilité et le bas prix des micro-ordinateurs et de leurs périphériques permet à l'ingénieur métallurgiste d'utiliser de tels ordinateurs pour diverses applications. Dans ce rapport, les auteurs décrivent le développement d'un système d bas prix pour l'acquisition des données, capable de mesurer jusqu'à huit canaux analogues jusqu’à une vitesse de 5000 mesures par seconde. Ce système est équipe avec son propre ""hardware"" et ""Software"" qui relient le micro-ordinateur d’un ordinateur central, comme le système de McGill pour computations réciproques (MUSIC). Ce central d'ordinateurs est soutenu par l'ordinateur AMDAHL V7. Utilisant cet "" interface"", la vitesse de communication entre Ie micro-ordinateur et l'ordinateur central peut atteindre jusqu'd 9600 (baud)."

Jan 1, 1980

By P. J. Williams, A. R. Foster

Petrographic studies, assay records, and laser ablation-inductively coupled plasma-mass spectrometer (LA-ICP-MS) analyses of major sulfides suggest nearly all of the gold at the Ernest Henry Cu-Au deposit occurs in the form of native gold or electrum (95-65 wt.% Au); sylvanite and dissolved gold in cobaltite, chalcopyrite, and pyrite make only minor contributions. LA-ICP-MS analyses of the gold contents of chalcopyrite gave from 8 to 139 ppb (mean = 56 ppb), more than an order of magnitude lower than those experimentally determined in chalcopyrite in equilibrium with native gold at the estimated mineralization temperatures (350°-450°C). Gold content is more variable in pyrite (1-400 ppb, mean = 77 ppb) and highest in narrow growth zones of a subordinate type of complexly zoned pyrite wherein it is associated with elevated As, Ag, Sn, Sb, Te, and Bi. Deposition of gold-electrum was closely associated with, but preceded some of the chalcopyrite deposition, as indicated by microtextures and lower bulk Au:Cu ratios in late-stage chalcopyrite-rich veins. Gold grains have maximum dimensions from <1 to 50 micrometers, and are heterogeneously distributed with most occurring in microscale clusters. Fifty-five out of 76 grains recorded in polished sections are in contact with both chalcopyrite and pyrite, and many of the rest are in sites where such a relationship could exist in the third dimension. The dominant textural sites are intergrowths with chalcopyrite in microveinlets cutting pyrite, and on faces of pyrite grains in contact with chalcopyrite. Scanning electron microscopy, electron microprobe analysis, and proton induced X-ray emission studies show that pyrite associated with gold includes complexly zoned, weakly zoned, arsenian, and arsenic-poor types. The textures are compatible with the possibility that most gold was deposited electrochemically as native metal on pyrite surfaces. The textural distribution of gold has important metallurgical implications given that the ore processing circuits at Ernest Henry and most other sulfide copper mines are designed to exclude pyrite (and arsenic) from concentrates.

Jan 1, 2007

By L. D. Smith

Net Present Value Impact of Discount Rate The Discounted Cash Flow (DCF) method of valuations is universally used and accepted. The main criticism of the method is that it does not recognize the value of projects long life projects. This can be seen in the preceding graph where the present value of cash flows in later years are small for discount rates over about 10%. This graph covers a project that has a 25 year operating life. It is clear from the low height of the NPV bars at 10% and 15% in the last years of the project that an additional 25 years would add almost no value to total project NPV. As an example of this effect, an colleague undertook the evaluation of a pulp and paper project. The plant could be justified, but it was not possible to justify planting the trees as they took too long to grow and so had not appreciable NPV. The plant had to purchase wood to feed the plant.

May 1, 2013

By B. Tanda

A process has been developed at Curtin University whereby glycine is used in an alkaline environment to leach gold, silver and copper from their ores, concentrates, process intermediates and wastes. Copper mineralisation investigated includes various oxides, sulfides and native copper. The leach process utilises an oxidising environment such as oxygen. Glycine is a non-toxic, non-volatile, edible, low cost reagent which is produced in large industrial quantities for use in several industries. Glycine and its copper and precious metals complexes are stable over wide pH, Eh and temperature ranges. Other than losses in leach residues, the glycine is recovered and recycled for leaching. Iron dissolution is insignificant in the pregnant leach solution. Iron in pyrite remains unaffected, whereas iron associated with base metal sulfides (e.g. chalcopyrite and bornite) is converted to a readily filterable iron hydroxide. Efficient separation of copper by solvent extraction and conventional electrowinning has been shown to be feasible for a number of organic extractants, whereas gold and silver glycinates adsorb very well onto carbon allowing CIP/CIL/CIC (carbon-in-column) based processes. The process is ideal for ores containing acid-consuming gangue, concentrates with high arsenic or halide contents and for copper-gold ores with significant sulfide mineralisation. The process eliminates many of the problems associated with the processing of copper-gold-silver ores, such as elemental sulfur formation, silica gels, unwanted metal co-dissolution, and jarosite precipitation. The reagents used and process residues are much safer and environmentally benign than conventional process options. The processing technology can be applied to in-situ, heap and vat, or agitated tank leaching at temperatures ranging from ambient to below 100?C at atmospheric pressure and is currently being commercialised. This paper will focus on copper leaching and recovery and iron rejection from a chalcopyrite flotation concentrate.

Jan 1, 2016

By Gregg S. Hill, Bert J. Huls

"This paper on coarse particle recovery (CPR) summarizes a process to capture coarse particles that are not recoverable by regular flotation. Several porphyry copper operations in the world operate analogous circuits that recover non-floated copper from tailings; however, the case presented here is unique in that extensive underlying test work has allowed us to elucidate some fundamental principles behind recovery enhancement. This paper discusses an overview of the flow sheet that is proposed to Minera Escondida Ltda., the nature of copper in the feed to the CPR circuit, and the various unit operations within the recovery circuit. Details of the technology behind each unit operation will be presented in later publications.INTRODUCTIONSince 1996 BHPBilliton and MEL (Minera Escondida Ltda.) have developed a process to recover copper from coarse particles in the rougher tailings. Copper recovery from fresh tailings is not new. Several operations in Chile, such as Chuquicamata, El Teniente (AMEC, 2003), Mantos Blancos and others have operated various forms of tailings circuits. Both Chuquicamata and El Teniente practice cascade flotation scalping off froth containing fine copper particles after allowing sufficient retention time, air inducement and, sometimes, additional reagent addition. Chuquicamata tailings are not segregated but floated in sequential cascade and conventional large cell arrangements. At the Valle Central operation of El Teniente a coarse fraction of mill tailings is ground and floated, with the rejects recombined with fine tailings and subjected to cascade flotation through a sequence of concrete launders as the tailings flow towards their final deposition area. Mantos Blancos cyclone the rougher tailings and blend the underflow with scavenger concentrate from elsewhere in the principal circuit prior to flotation in Wemco Cells. Kemess in BC, Canada operates a 160 m3 Outokumpu cell to reduce the tailings sulfur content (Rasmussen, et.al, 2004)."

Jan 1, 2005

By K. Norris

"The Campbell mill has undergone numerous changes over the past 43 years. However the rate of change has increased significantly in the last 4 years. A new grinding circuit, carbon-in- pulp circuit, pressure oxidation plant, and column flotation circuit are all new additions. Other changes have occurred in the last 2 years including a large reduction in sodium cyanide consumption, and the introduction of a computer controlled grinding circuit. More improvements are planned in the next 2 years. Some of these improvements include the construction of an effluent treatment plant, and the replacement of filtering and Merrill-Crowe precipitation with carbon-in-leach and electrowinning.Recent changes and improvements to the Campbell mill are a commitment by Campbell mill personnel and Placer Dome Inc. to decrease operating costs, increase gold recovery and gold production, improve industrial hygiene and safety, and meet environmental compliance with current government legislation.INTRODUCTIONThe Campbell Mine has been and continues to be one of Canada's premier gold mines. Campbell Mine is 100% owned and operated by Placer Dome Incorporated. Milling of ore commenced in 1949 at a rate of 300 tons/day producing 58,000 ounces per year of gold. In 1992 Campbell Mine will mill 1340 tons/day of ore at a grade of 0.6 ounces/ton, producing 275,000 ounces of gold at a cash cost of $205.00 Cdn./ounce.This paper discusses some of the changes that have been made to the Campbell mill in the past 4 years. The flowsheet has undergone extensive changes and will continue to change rapidly in the next 2 to 3 years. A simplified flowsheet of the Campbell mill is shown in figure 1."

Jan 1, 1992