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By T. G. Joseph

Mines must manage variability from within their operations as well as those imposed upon them by external forces. This paper provides a framework to manage both internal and external variability through the review and adjustment of the mine plan where applicable to minimize lost production and maintain operational safety.

Nov 1, 2011

By Stephen Hammond

?Our own prejudices form the greatest barrier to creating an inclusive working environment.? Have you witnessed? Racism or Negative Comments about an Aboriginal Person? ?You are free to compete with all the others?, and still justly believe that you have been completely fair.? Lyndon B. Johnson

May 1, 2008

By Dave Bulled, Jim Thompson, Tim Leriche, Mark Blake, Troy Wilkie

"A commitment to a core testing, plant modeling and reconciling technique has shown substantial economic benefits to IOC in terms of accurate production forecasting, smoother operation of the mill, improved expectations of throughput and co-operation across production departments from geology, planning, mining, and processing, to shipping of concentrate to market.This paper describes a successful seven year program of forecasting throughput of the autogenous milling circuit at the Carol Lake concentrator of IOC. Work started with audits of the grinding circuit in 2001 and benchmarking of the data collected from samples of mill feed and plant operation to the CEET mill design and throughput forecasting model.Initially 390 drill core samples were tested for SAG Power Index (SPI) to measure the energy required in milling, and the data distributed using a geostatistical technique across the two operating pits, so that hardness was estimated in each of the 40,000 blocks (or 1500 million tons) of potential ore. In 2004 a forecast of energy requirement, i.e. forecast of throughput for a given power availability at the mill, was produced for each ore block using the CEET model and used for mine planning to smooth plant throughput. The forecast for blocks mined on a monthly basis was reconciled with plant results over the next 2 years and minor changes made to the CEET model. The forecasting exercise was repeated in 2006 and in 2008 with the latest model based on the testing of almost 1300 samples of drill core at closer spacing.INTRODUCTIONThe contracting of sales to clients and the timely supply of products to meet those contracts is a cornerstone of good business practice. Ensuring the correct scheduling of production is a major concern of mining companies where the supply and qualities of the raw material is uncertain and production facilities are not flexible. This is particularly challenging when the product is of high volume and produced far from the customer, such as iron ore.Apart from the metal content of the ore being mined, the greatest impact on production scheduling is the throughput of the comminution section of the extraction plant; most notably when size reduction is achieved by autogenous grinding. The response of the mills to variability in the hardness of the ore can change throughput by as much as 50% from day to day at some plants."

Jan 1, 2009

By Gordon E. Agar, Brian Lyons, Gregory H. Styles, William B. Kipkie

"Rock rejection during the flotation of a copper-nickel ore was improved by adding carboxymethyl cellulose to both a rougher and cleaner flotation stage. The selection of the rock depressant was based on laboratory rates studies. Plant operating results are presented which confirm the laboratory selection of two particular brands of carboxymethyl cellulose.The rock assay of the concentrate was reduced from more than 40% to less than 15%.IntroductionThe traditional method of selecting flotation reagents relied upon batch bench scale tests, conducted under arbitrary conditions, to identify the effect of the reagent under examination. Too often these were ""one-off"" tests with little or no regard paid to the reproducibility of the results. Sophisticated researchers used statistical methods to design and evaluate the experiments but they were still obliged to rely on the arbitrary and often unreliable batch tests to generate the numbers that were analyzed statistically. An interesting side-effect of the enhanced sophistication of the statistical analysis was often that no significant effects would be uncovered in a series of experiments that would have generated many positive conclusions and much further experimentation if the same results had been evaluated by the traditional method.In the recent past, at least two groups of researchers a have directed their attention to the reliability of the batch experiments with a view toward improving the reproducibility of the test data. In this work the best of the improvements advocated by both of these groups have been adopted in order to generate kinetic data from batch tests that are as reproducible as possible.The objective of the work was to reduce the rock content of a bulk sulphide concentrate produced at Inco's Shebandowan mill. During 1982 the Shebandowan concentrate analyzed 3.5% Cu, 7.4010 Ni, 25% pyrrhotite and more than 40% rock, which resulted in an MgO content of 10.4%. Besides the expense of shipping all of this rock to Sudbury, the rock also contributed to the poor filterability of the concentrate. On favourable occasions the moisture content of the filter cake was slightly over 20% by weight. The magnesia content of the concentrate was deleterious to the reverberatory furnaces used by Inco for smelting nickel concentrate because the slag viscosity increased as the magnesia content increased, and the nickel lost in the slag went up."

Jan 1, 1987

By Robert B. Parsons

"The Canadian mining industry is not off to a good start in the 1993/94 budget season. Of the five provinces and territories to table budgets as of March 31, 1993, the industry's scorecard shows: one win, one tie, and three losses.IntroductionBy the end of March, five of Canada's twelve provincial and territorial governments had tabled their 1993/94 budgets. The mining industry is off to a bad start. The industry's scorecard shows one win, one tie, and three losses. Only Newfoundland appears to be paying any attention to the industry's concerns about the impact of taxation on competitiveness. It is particularly disconcerting to see that non-profit based taxes continue to increase, at a time when these taxes are the focus of a united attack by the entire industry.NewfoundlandFirst, the good news. On March 18, 1993, Finance Minister Winston Baker announced the following changes to the province's mining tax regime:"

Jan 1, 1993

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 Paul Gauthier

Aujourd?hui, avec un faible prix de l?or sur le marché, les opérateurs miniers doivent revoir leur façon de faire. La méthode de minage «Eureka» permet de réduire les coûts de production et d?accélérer la mise en production des chantiers. Les principales étapes du cycle de minage et les problématiques associées à l?utilisation de cette méthode à la Mine Bousquet y sont décrites.

Oct 1, 2001

By Rob Sloan, Simon Yu, Rob Robison, Mark Schmidt

"In 2000-2009, Highland Valley Copper (HVC) tested new generation 660 mm cyclones supplied by various manufacturers in an aim to replace existing first generation 762 mm cyclones without success. Due to plant infrastructure limitations, new generation larger (838 and 800 mm) cyclones were not feasible. In 2010, an approach of testing hybrid 800 mm diameter cyclones was initiated by HVC. The hybrid cyclone consists of an 800 mm cyclone upper head section and the use of existing 762 mm cyclone conical sections. Three hybrid 800 mm cyclones were engineered and fabricated, targeting a throughput of 850-950 mtph and were installed in the E line cyclone cluster. Since starting operation on September 20, 2011, three hybrid 800 mm cyclones have been running at combined throughput ranges of 750 to 1050 mtph. Based on plant Daily Met Reports, the test hybrid cyclones demonstrated a decrease in misplacement of coarse copper bearing material to the cyclone overflow and better cyclone efficiency when compared to the existing 762 mm cyclones at the same throughput. The hybrid 800 mm cyclones also demonstrated significantly higher capacity per unit when compared to the existing cyclones. Based on the improvement demonstrated in the full plant trials, HVC decided to install the new hybrid 800 mm cyclones in all five grinding lines starting in July, 2012. A more detailed discussion of the full plant trials and initial results of the first complete retrofit of E line will be presented. INTRODUCTIONHighland Valley Copper Partnership (HVC) is Canada’s largest base metals mine and one of the world’s largest producers of Cu-in-concentrate. The mine, located in the central interior of British Columbia, is owned (97.5% interest) and operated by Teck Resources Ltd. In 2011, HVC produced about 210 million lbs. of Cu and 8 million lbs. of Mo. HVC’s Mill Modernization Project (MOP), which was budgeted for $475 M, is currently under intensive construction and is scheduled for commissioning in Q1 2014. The following description was valid at the time of writing this paper.The operation has been expanded a number of times since the startup of the original Lornex mill in 1972. The plant started up with two 9.75 m (32 foot) diameter primary SAG mills. It was expanded in 1981 with the addition of a 10.36 m (34 foot) diameter SAG mill. In 1988, the Highmont concentrator grinding mills and flotation section were moved and attached to the Lornex mill site. This added two10.36 m (34 foot) diameter AG primary mills to the Highland mill. This brought the total number of primary mills to five referred to as Line A, B, C, D and E: three SAG mills (A, B and C) each with two ball mills in parallel and two AG mills (D and E) each with one ball mill. Each AG mill line is equipped with one short head pebble crusher. Ball mill circuits are classified using 8 clusters of ten Linatex 762 mm cyclones to reach a target P80 330 micron (equivalent 43% +100 mesh), before the cyclone overflow product advances to the bulk flotation circuit."

Jan 1, 2013

By Jan E. Nesset, James A. Finch, Wei Zhang

"Bubbles are unquestionably the heart of the flotation process. Their size and combined surface area are largely what drive the recovery process. This suggests that plant engineers should be aware of where their plants are operating with respect to what is achievable for these key parameters. The paper presents a model of how the key operating variables of frother type and concentration, gas rate, altitude (above sea level) and viscosity affect the Sauter mean bubble size (D32) and bubble surface area flux (Sb). The results are compared to a set of plant measurements that demonstrate the benchmarking capability of the approach. A case study is used to link hydrodynamic change to improved metallurgical performance.INTRODUCTION At the beginning of the 20th Century the early practitioners of flotation were aware of the importance of understanding bubble behaviour (Rickard, 1916) but measurement of individual bubble and gas behaviour in the industrial environment was not possible due to a lack of adequate sensors. This situation was not rectified until three quarters of a century later with the advent of industrially-robust sensors developed, notably, at the University of Queensland’s Julius Kruttschnitt Mineral Research Centre (JKMRC) (Schwarz & Alexander, 2006) and McGill University (Gomez & Finch, 2002). What emerged was not the chaotic environment perhaps expected, but defined relationships between gas rate, gas holdup, bubble size and the total surface area of bubbles. These relationships could be defined by mathematical expressions and predicted from an understanding of the key process variables (Gorain, Franzidis & Manlapig, 1997; 1999) (Hernandez-Aguilar, Gomez & Finch, 2002) (Gomez, Cortes-Lopez & Finch, 2003) (Nesset, Gomez & Finch, 2007). The early JKMRC work focused on a large pilot cell (3 m3) installed in plant environments, while the McGill work was initiated on flotation columns (Finch & Dobby, 1990) (Xu, Finch & Uribe-Sales, 1991) and later adapted to industrial mechanical cells (Cooper, Scott, Dahlke, Finch & Gomez, 2004) (Dahlke, Gomez & Finch, 2005) (Nesset, Gomez, Finch, Hernandez-Aguilar & Difeo, 2005). Yianatos of Santa Maria University (Chile), a graduate of the McGill research team, carried the work to industrial settings in South and Central America (Yianatos, Bergh, Condori & Aguilera, 2001). The methods of gas dispersion measurement are now well accepted and most major research centres and flotation cell manufacturers have adopted the technology (Pyecha, Sim, Lacouture, Hope & Stradling, 2006) (Yañez et al., 2009) (Collins, Schwarz & Alexander, 2009)."

Jan 1, 2012

A rough simulated borehole has been developed for the installation and dynamic testing of rock bolts a the WASM Dynamic Test Facility. The rough simulated borehole is used for rock bolts that are sensitive to equipment installation technique or borehole geometry (particularly friction rock stabilisers and resin encapsulated bolts). An extensive axial test program has quantified a difference between the static and dynamic capacity (kN/m of embedment) for friction rock stabilisers once sliding starts. The 47mm split tube bolt has a 50% reduction in embedment capacity (but with significant variation) dissipating 2.7kJ/100mm of sliding per meter of embedment, and the Omega (inflatable) bolt had a 70% reduction in embedment capacity dissipating 6.2kJ/100mm of sliding per meter of embedment. The Omega bolt dynamic capacity remainder at least equivalent to the split tube bolt static capacity.

May 1, 2009

"A simple approach to optimizing the performance of an operating carbon in pulp (CIP) or carbon in leach (CIL) plant is presented. It is possible to reproduce the performance of an operating CIP or CIL plant in the laboratory, in small scale batch tests in which the rates of gold leaching and carbon adsorption are determined, coupled with mathematical models that translate the batch kinetic data into predicted steady state profiles of gold in solution and on the carbon across multi-stage adsorption circuits.Once the performance of the commercial plant has been mimicked by the model, the plant operating parameters can be varied systematically in the model, and the likely response of the plant to the stepwise change can be determined. In this way it is possible to inexpensively optimize the design of both greenfields CIP or CIL circuits and plant expansions, or optimize the operating parameters of an existing plant, with no disruption to plant operations and no economic risk to the mining company.This approach has been adopted by IAMGOLD Corporation, to the immediate benefit of two of their existing gold operations. The methodology adopted and the results achieved are presented.INTRODUCTIONThe carbon in pulp (CIP) and carbon in leach (CIL) processes became firmly established in the gold mining industry in the 1980s, initially in South Africa and Australia, from where they spread rapidly to all the gold producing regions of the world. The percentage of annual global gold production by activated carbon-based processes grew from zero in the 1970s to almost 70% by the turn of the century, which represented a phenomenal rate of acceptance of a new technology by a traditionally conservative industry. The main reason for this rapid acceptance of the new technology was the fact that the first few large plants built in South Africa convincingly demonstrated better gold recoveries than the traditional filtration/Merrill Crowe process, with lower capital and operating costs. And as the plants developed an operating track record over their first few years of life, they proved to be remarkably robust mechanically, and highly tolerant of plant upsets, changes in feed composition and solution phase contaminants that had caused problems in Merrill Crowe plants."

Jan 1, 2011

By S. Kelebek, C. Gibson, M. Aghamirian

"Global niobium production is currently dominated by three operating mines, Araxá and Catalão in Brazil, and Niobec in Canada. Although over 90% of the world’s niobium is mined and processed in Brazil, a number of high grade niobium deposits exist worldwide. The advancement of these deposits depends largely on the development of operable beneficiation flowsheets. Pyrochlore, the primary niobium bearing mineral, is typically upgraded by flotation with amine collectors at acidic pH, and often includes a reverse gangue flotation stage prior to pyrochlore flotation. Challenges related to the flotation of niobium ores include complicated flowsheets which require pulp pH adjustment from alkaline to highly acidic conditions, difficulty recovering fine grained pyrochlore, producing concentrates that meet specifications, and minimizing the losses to reverse pre-flotation gangue concentrates, slimes, and tailings. The specific flotation challenges associated with different niobium ores are discussed. In some cases, the use of alternate flotation reagents and flowsheets are required to achieve reasonable gangue rejection and maximize recovery, particularly of very fine pyrochlore grains.INTRODUCTIONNiobium is a transition metal primarily found in the oxide minerals pyrochlore (Ca,Na)2Nb2O6(OH,F) and columbite (Fe,Mn)Nb2O6. After physical upgrading, pyrochlore is converted into a ferroniobium product which is largely used in the production of high strength low-alloy steel. Today’s niobium market is dominated by the Companhia Brasileira de Metalurgia e Mineração, whose Araxá operation produces over 80% of the world’s niobium. There are two smaller operations, Niobec in Canada, and Catalão in Brazil, which account for the remaining production (U.S. Geological Survey, 2013).A number of niobium deposits exist globally, their advancement dependent on the development of operable beneficiation flowsheets. Pyrochlore, the predominant niobium bearing mineral, is commonly upgraded by flotation with cationic amine collectors in acidic pulp conditions. However, many niobium ores do not respond to this typical flowsheet because they are either highly refractory or niobium deports to other minerals such as columbite, ilmenite and rutile, which are not as responsive to this reagent scheme (Bulatovic, 2010). Other reagents, such as alkyl hydroxamic acid, have been studied extensively and while promising, are not without their own inherent issues including lack of selectivity over iron oxide minerals, and high addition rates (Ni & Liu, 2012; Gorlovskii, Eropkiny, Koval, Strelstin, Khobotova, & Shtchukina, 1968; Gorlovskii, Khobatova, & Shtchukina, 1966).It is the aim of this report to highlight the challenges associated with the physical upgrading of niobium minerals through examination of the flotation behavior of two different ore systems. In order to overcome these challenges it is important to thoroughly understand the limitations of typical flowsheets/reagent schemes currently employed in operation."

Jan 1, 2015

By Ernest Baafi

A simulation model RoadSIM using the ARENA modelling system has been developed to evaluate roadway development options for a given development panel configuration. The RoadSIM simulation system has provisions for variability/randomness in operations including cutting and loading at the face, tramming and discharge of coal to the boot end and availability of equipment. The modelling system provides a means for assessing the operational limitations of roadway development practices at a particular coalmine. It is a ?what if? tool that allows a range of equipment, configurations and operating practices to be assessed in terms of achievable advance rates and equipment utilisation. Output from the system is in the form of a dynamic visualisation as well as summary reports and detailed logs of operations over time.

Oct 1, 2009

By R. S. Simkus, J. R. Egan

"Changes have recently been applied to the Sullivan Concentrator lead and zinc circuits to treat fine-grained ores which make-up the majority of ore reserves in the mine. Pilot plant test work conducted in 1990-91 indicated that concentrate grades would be substantially improved by reducing the particle size (P,0) of the lead from 38 to 15 µm and the zinc from 45 to 24 µm.Circuit revisions involved installation of major new equipment including: two GUO kilowatt Vertimills for regrinding, a 4 metre diameter column flotation cell and a 4 metre diameter hyperbaric pressure filter for dewatering. Duties of the existing regrind mills were reassigned.IntroductionThe Sullivan ore body is a massive sulphide deposit consisting of fine grained mixtures of sulphides, sometimes inter-banded with country rock and varying widely in their content of lead, zinc, iron and silicates. Principal economic minerals are marmatite and galena. Iron is mainly present as pyrrhotite (85%), and to a lesser extent as pyrite (15%) .The orebody has been actively mined since 1923, with 1992 ore reserves estimated at 15,800,000 tonnes with an average grade of 4. 7% lead and 7. 9% zinc. Current plans call for treatment of 1,600,000 tonnes/year, (7,000 tonnes per operating day), with flotation feed grades of 5.9% lead, 10.1% zinc, and 22.0% iron."

Jan 1, 1994

By M. Kalin

"Ecological Engineering, a biotechnological approach to the decommissioning of base metal mining wastes, is being tested on two pits (Gloryholes) in Newfoundland, Canada. Pit #2 has an average pH of 3.5 and flows into Pit #1 where, through additional ground water contribution, the pH is circumneutral, ranging between 5.5 to 7.The AMD in Pit #2 originates from underground workings and exposed massive sulphide on the pit walls. The overflow from Pit #1 averages about 10 L/s with less than 0.2 mg/L of Cu and 40 mg/L of Zn.Ecological Engineering utilizes organic substrate as a source of carbon and nutrients for microbial populations which can generate alkalinity and reduce metals. In 1989, limnocorrals (enclosures of 4 m diameter and approx 3 m depth) were placed in both pits to test the most suitable organic amendment (peat and sawdust). Microbial alkalinitygeneration was evident 95 days after placement of the amendment on July 4, 1989. The pH had increased after 120 days from 3.5 to 4.5 and by day 480 the pH was 7 in limnocorrals in Pit #2. Zinc concentrations in the limnocorrals in Pit #2, dropped from an average of 35 mg/L to about 2 mg/L or less, by day 480.A scaled-up experiment has been under way since August 25, 1990, where 390 m3 are treated in pit #2 and 750 m3 in Pit #1. One hundred eighty days after placement of the amendment, zinc was reduced in the acid Pit #2 from 40 mg/L to 15 mg/L. Research is underway to determine those factors which limit microbial activity."

Jan 1, 1992

By S. W. Stogran

"Chemical and limited biological monitoring of mine and mill effluents are being used by regulatory agencies to monitor and control discharges to the environment. Amendments to the Federal Fisheries Act may make it mandatory for mines to conduct Environmental Effects Monitoring (EEM) which will change the emphasis from monitoring effluents to monitoring impacts on receiving waters. The EEM amendments may expand the scope of present environmental studies to include: effluent mixing zone delineation; inventory and classification of resource, habitat, and historical receiving environment; effluent quality determination; chronic and acute bioassay testing; tissue analysis; benthic invertebrate monitoring; fish population surveying; fish tainting evaluation; and the evaluation of impacts on fish habitat, invertebrate communities and fisheries resources. The requirements for EEM have not yet been worked out by the mining industry and the government committee. Experience at Lakefield Research in conducting biological monitoring studies for the mining industry has shown that biological monitoring may be useful for assessing environmental impacts only if programs are planned and executed to collect relevant data, thus minimizing costs and maximizing effectiveness.IntroductionThe chemical monitoring of effluents and water bodies receiving effluents is common practice in the Canadian mining industry and has been used routinely by regulatory agencies to control discharges to the environment. Biological monitoring has also been used on a limited basis, primarily to augment chemical data collected. A number of regulatory bodies, primarily in Canada and the United States, have been incorporating biological monitoring into environmental regulations.Various forms of biological monitoring techniques have been used in Canada and the United States to help assess the impact of mining operations and effluents on the environment. Biological monitoring includes a wide range of activities, from monitoring metal uptake in individual organisms to examining the population dynamics in ecosystems. The most commonly employed biological monitoring techniques are the chronic lethality toxicity tests. Also becoming widely used are in situ and chronic toxicity tests."

Jan 1, 1994

By Rees J. Llewellyn

Improved product development, assessment methods and evaluation studies of materials for oil sands applications have traditionally focused on low and high stress abrasion and slurry erosion resistance mechanisms, because they were considered to be the predominant wear modes prevailing in oil sands mining, transportation and bitumen recovery. More recently with the very successful introduction of oil sands hydraulic transportation systems, there has been increasing use of crusher systems in which materials of construction are also required to have good toughness and gouging abrasion properties to withstand impact and the severe indentation and ploughing forces that are involved. To assess material property requirements for mitigating this additional wear mechanism, jaw crusher gouging abrasion tests using a modified ASTM G81 procedure, have been carried out on a range of wear materials of interest for oil sands mining service. The method involves a comparison of the wear losses that occur for reference and selected test plates when a controlled amount of standard feed rock is comminuted in a laboratory jaw crusher. Among the classes of material evaluated have been Q&T plate steels, austenitic manganese steel, chromium and chromium molybdenum white irons as plain castings and in laminated forms and also chromium carbide and tungsten carbide overlaid wear plates.

May 1, 2004

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 James A. Brown, Marius Botha, Christopher A. Fleming

"The technical and economic feasibility or re-processing hundreds of millions of tons of tailings in a number of historic gold tailings dams in the Witwatersrand area of South Africa is being investigated. The objective is to recover uranium and residual gold from the tailings, as well as to oxidize the sulphides to eliminate long term environmental liabilities associated with acid mine drainage. The tailings from the re-processing plant will be re-deposited in a new area far from urbanization, allowing for the rehabilitation of the real estate currently occupied by these historic tailings.The first step in the process involves a mild-regrind and mild acid leach of the tailings (pH 2.5 to 3.0) to dissolve up to 40% of the uranium. This uranium is recovered directly from the pulp by resin in pulp (RIP) with a strong base resin. The RIP tails are then treated by flotation to recover a rougher pyrite concentrate, and flotation tailings that are discarded. The rougher concentrate is cleaned to produce a final pyrite concentrate and cleaner scavenger tailings, and the pyrite concentrate is oxidized in an autoclave to leach uranium and generate acid. The autoclave discharge is combined with the cleaner scavenger tails, and the acid and ferric ions generated in the autoclave are used to leach more uranium and oxidize more sulphide in the cleaner tails. The product from the concentrate leach circuit is processed by resin in pulp for uranium recovery, followed by neutralization, cyanidation and carbon in pulp for gold recovery.The rougher float tails may be further treated to recover gold that was not recovered in flotation, but which had been liberated from the old dumps by natural oxidation of some of the pyrite over many decades. The float tails would be neutralized and treated by cyanidation and CIL to recover this liberated gold.All parts of the flowsheet have been extensively tested in the laboratory, and the critical elements of flotation, pressure oxidation and resin in pulp have been demonstrated in pilot plants. The results of the hydrometallurgical investigations are presented here."

Jan 1, 2010

By Juan Anes, Dominic Fragomeni, Tim Edwards, Dave Scott, Simon Yu

"The Montcalm concentrator operation was successfully commissioned in fall of 2004 at the Xstrata Copper’s Kidd Creek Metallurgical Site, Timmins. The start-up met or exceeded the Type 1 profile as defined by McNulty. Since the life-of-mine was estimated at seven years, concentrator optimisation endeavours had to be fast-tracked. These joint endeavours between the Kidd Creek Metallurgical Site staff and Xstrata Process Support were focussed on increasing ore treatment capacity and metallurgical performance. This paper reviews these endeavours. A flotation circuit survey, together with appropriate Process Mineralogy measurements, identified recovery opportunities in both locked and overground pentlandite in final tailings. The bypassing of first rougher concentrate directly to final concentrate was also recommended, given the composition of that stream. A subsequent grinding circuit survey identified a low circulating load due to poor classification performance. Modelling of these data suggested a change to the cyclone nest and pumping arrangements in the grinding circuit. Implementation of these recommendations has led to a 25% gain in milling circuit capacity as well as improved flotation circuit performance. These improvements amount to nickel and copper recovery gains of 2.57 and 1.83% respectively.INTRODUCTIONHistoryThe Montcalm Ni/Cu Ore is processed in a spare division of the Xstrata Copper’s Kidd Creek concentrator, located near Timmins in Northern Ontario. The flowsheet had been specified by earlier work, and the project fast-tracked so as to commission production operations into a time of rising nickel and copper prices. The Montcalm flow sheet starts with on-site ore crushing to - 19 mm. The crushed ore is trucked to the concentrator. This off-site crushing minimizes contamination with the Kidd Creek Cu/Zn ore. In the concentrator, rod and ball mill grinding to a target p80 of 39 µm produces the Rougher Flotation Feed. Flotation to Bulk Concentrate follows as Cu/Ni roughing and two stages of cleaning. Bulk concentrate is subjected to Cu/Ni separation using conventional column cells. Xanthate is the collector and MIBC is used as frother. Depramin C, a CMC (Carboxy Methyl Cellulose) is added to depress ferromagnesian silicates in the flotation process."

Jan 1, 2009