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By K. D. Hester

"1.0 INTRODUCTIONThe uranium industry started in Canada with the reopening of the gravity concentrator at Eldorado's Port Radium mine in the North West Territories in 1942. In 1948, uranium exploration and processing was opened to the private sector, and the Federal government offered special pricing incentives to the industry. Eldorado explored the Lake Athabaska deposits in northern Saskatchewan, and in 1953 opened the Beaverlodge mine. Other mines in the area soon followed. In 1953 also, the deposits in the Blind River - Elliot Lake area and in the Bancroft area of Ontario were discovered. Mines and mills were quickly developed in these areas.Canadian uranium production peaked at 15,900 short tons of U3O8 in 1959. In that year, uranium exports at $300,000,000 exceeded those of all other minerals in value. On October 1, 1959, Canadian uranium operations employed 13,900 people.Up to 1956, it was a seller's market. By 1958, world production of uranium was far ahead of requirements. Accordingly, in November of 1959, the USAEC announced it would not renew it's options for continued delivery of uranium from Canadian mines. This led to the ""stretchout"" of existing uranium contracts, and many mines were shut down (see Table 1) .In the early 1970's, a commercial uranium market seemed to be developing. In Ontario, at Elliot Lake and Bancroft, mines reopened. But competition was coming from the Athabaska basin of Saskatchewan. Currently it is these high grade, open pit deposits of northern Saskatchewan which are in the forefront of Canadian uranium developments. Canadian developments since 1942 reflect the political and market forces, as well as metallurgical progress and changes in environmental standards. This paper attempts to show these process changes in broad perspective."

Jan 1, 1987

By Chris Larsen, Carole Fortin, Dave Scott, Curtis Deredin, Ian Orford, Jean Guy Gauthier, Andy Trusiak, Lyne Côté, Mike Cooper

"Upon successful commissioning of the Stage Grinding Project (Cormier et. al., 2002), process improvements predicted through pilot plant testing were obtained in several flotation circuits, resulting in higher grades and recoveries for zinc and lead concentrates. Subsequent to establishing new baseline operating conditions from the Stage Grind Project implementation, additional opportunities were identified, and through the application of Six Sigma methodologies further gains were made. Six Sigma improvement projects were carried out in the copper-lead, zinc, lead upgrading and bulk flotation circuits. The overall performance increase resulting from incremental improvement projects has been substantial.Most remarkably, given the operational maturity up to the late 1980’s, the Brunswick concentrator team has continued to deliver a steady stream of major improvements over the past fifteen years. While senior managers and their programs have changed several times, there have been some critical constants over the long run. Common elements have been a commitment to team work, a commitment to recruit and maintain technical personnel, a structured business improvement framework supported organizationally by senior management, and focus on a few priority initiatives rather than trying to fix everything at once.The paper briefly discusses the longer term setting and then endeavors to illustrate, with examples, how improvements are presently achieved by applying the Six Sigma quality program.INTRODUCTIONThe Noranda Inc. Brunswick Mine, located near Bathurst, New Brunswick, is one of the world’s larger lead/zinc mines. Milling of ore began in 1964 from the No. 12 orebody, with an expansion in 1966 to accommodate ore from the No. 6 mine. In excess of 100 million tonnes have been milled to date. The concentrator employs differential flotation to produce lead, zinc, copper, and lead/zinc bulk concentrates. The ore is massive sulphide, with approximately 20% valuable minerals, 60% pyrite and 20% silicates."

Jan 1, 2005

By Sylvie Brassard

Available information ?? InfoMine: mineral properties ?? Metals Economics Group: budgeted exploration expenses ?? MineScan: Canadian and American Mining Companies ?? Statistics Canada: Canadian Direct Investment Abroad, by Sector in the world OR all sectors by Country

May 1, 2008

This paper describes the back analysis of the Pavoncelli tunnel, an hydraulic tunnel which was excavated between 1904 and 1915 in South of Italy and experienced severe damages during the 1980 Irpino-Lucano earthquake. A numerical simulation which is intended to study the behaviour of the tunnel during this seismic event is presented, also accounting for the swelling phenomenon that took place during and after construction.

May 1, 2009

By Hossein Aminian, Daniel Hodouin, Claude Bazin, Claude Jacob

"Solvent extraction followed by electrowinning (SXEW) is an economical option for the processing of low grade and oxidized copper ore. Phenomenological models were developed to simulate the copper solvent extraction and the electrowinning processes. The two models were linked together to make a SX/EW simulator. The simulator is used to predict the operation of the mines Gaspe pilot plant put in operation in 1996. Results confirm the potential of the simulation that would subsequently be used for student training, process optimization and to assess the performances of control strategies.INTRODUCTIONSolvent extraction followed by electrowinning (SXEW) has become in the last two decades a key process for the recovery of copper from solution obtained by leaching low grade copper ore. Several operations have been commissioned in North and South Americas in the last decade (Arbiter, 1994). In Canada, Gibraltar Mine (Scott, 1991) operates a SX plant followed by electrowinning (EW) to produce copper cathode from leached low-grade ore dumps. From 1996 to 1997 Mines Gaspe operated a pilot plant to test the economical feasibility of leaching an oxidized copper ore, followed by solvent extraction and electrowinning of copper. Despite copper SX/EW processes have the reputation of being low cost operations, plant engineers should always look at way to make the plant more efficient. Process models provide an economic platform to learn, control and ultimately optimize the operation of a plant.Several models have been independently proposed to simulate the SX process (Cadman and Hsu, 1970; Medina Gomez, 1980; Wilkinson and Ingham, 1983; Garcia et al., 1988; Aminian et al., 1997) and the EW process (Bryson, 1981; Barton and Scott, 1992; Barton and Scott, 1993). However few papers, if any, deal with the integration of the two process models into a single simulator of a SX-EW plant. This paper describes the development of an integrated simulator for the SX-EW process and shows some steady-state simulation runs of an actual SX-EW pilot plant. The paper consists of four sections. The first section shows the general layout and principles of operation of a SX-EW plant.The second section describes the SX model while the third section deals with the process model used for the copper electrowinning process. The last section shows how the two process models are linked to simulate the operation of the Gaspe pilot plant."

Jan 1, 1999

By John G. Payne

The Pebble deposit contains three contiguous zones. In the Pebble West zone, granodiorite stocks intrude gently warped volcanosedimentary rocks that had been intruded by diorite sills and two felsic intrusion breccias. In the Central zone, volcanosedimentary rocks are cut by diorite and granodiorite sills; the latter are genetically associated with the granodiorite stocks. In these zones, widespread potassic alteration consists of brown biotite and K-feldspar, with abundant quartz-carbonate-sulphide vein stockworks. Chalcopyrite/pyrite ratios range from 2/1 to 1/20. Diorite hosts the highest-grade mineralization, with much of it being disseminated. Patchy, later phyllic alteration is moderate and commonly depleted in copper. The Pebble East zone occupies a granodiorite stock and intruded host rocks below an eastwardly thickening wedge of barren Tertiary volcanic and sedimentary rocks up to 600 m thick. Brown biotite alteration and copper mineralization are strong, with chalcopyrite/pyrite ratios commonly over 1/1. The zone extends to a depth of at least 1200 m below surface; some drill holes bottomed in strong mineralization. Later, weak to moderate sericitic alteration removed some chalcopyrite and locally remobilized gold. The Pebble deposit has a Measured/Indicated resource of 3 billion tonnes grading 0.28% Cu, 0.32 g/t Au and 0.015% Mo (= 0.5% copper-equivalent) and an Inferred resource of 1.13 billion tonnes grading 0.30 g/t Au, 0.27% Cu and 0.015% Mo (0.55% copper-equivalent). The Pebble East zone has an Inferred resource of 2.13 billion tonnes grading 0.55% Cu, 0.34 g/t Au, and 0.037% Mo (0.97% copper-equivalent). The Pebble East zone is open to the east and to a lesser extent to the north, south, and to depth.

May 1, 2006

By Ronald L. Bruening

IBC has developed a cost effective MRT process for the selective extraction and recovery of gold, copper, and a mixture of other base metals from mine leach cyanide solutions. This is a two-stage system in which the gold is first recovered selectively as a high purity salt. The copper is then recovered separately as a sulfate salt. The other base metals are then collected as a cyano anion concentrate. Three different SuperLig® materials are used. The first stage can be used alone on gold leach solutions where copper and other base metals are not a problem. The two or three stage system is used when the base metals build up in the leach solution, resulting in increased costs. The cyanide or cyanide/cyano anion concentrate can be recycled back to the leach solution until the build-up of other salts, etc. becomes too high, or this too can be controlled with a percentage bleed stream.

Oct 1, 2003

By W. J. Young, K. B. Macneill, C. N. Smith

"A BRIEF HISTORY OF THE MURRAY BROOK MINERAL DEPOSITDuring the mid-1950's intensive exploration activity in northern New Brunswick followed the discovery of the world class Brunswick base metal deposit. Using the prototypes of modern airborne geophysical and geochemical exploration techniques many mineralized areas in the Bathurst-Newcastle area were quickly identified. This base metal - silver camp is situated within the metavolcanic - metasidementary rocks of the Tetagouche Group which forms a roughly circular caldera-chaped voloanio complex of Ordivician age.One of the early results in the exploration history in the camp was the discovery of the Murray Brook Deposit by Kennco Explorations, (Canada) Limited. During routine ground checking of geophysical anomalies, most of which turned out to be graphitic schist, the discovery of some copper bearing float was made by the exploration team. This encouraged the company sufficiently to carry out a regional stream sampling program which lead to a large anomaly associated with a hematitic gossan. Diamond drilling of a weak Slingram anomaly over the gossan zone resulted in the discovery of massive sulphide lenses. This was followed in 1956-7 with an intensive drilling program. The result was the delineation of a potential ore body containing an estimated 23 million tons with an overall grade of 0.44% copper, 0.86% lead, 1.95% zinc, 25.73 g/tonne (0.91 oz/ton) silver, 0.28 g/tonne (0.01 oz/ton) gold. Within this package were higher grade zones of copper and lead-zinc mineralization approaching ore grades.A thick blanket of gossan was present and is reported to have caused the drillers considerable trouble as they attempted to penetrate it to get to the underlying sulphides. The gossan, consisting of iron oxides and silica fragments sits on top of the massive sulphides and attains a remarkable thickness of 45.5 meters (150'). Early work had suggested that the gossan was enriched in gold and silver. If this were the case and if the precious metal could be leached out with cyanide, then mining and recovering those values might be economic.With this in mind Northumberland Mines Limited optioned the property from Kennco in 1985. Preliminary leach tests indicated that indeed the gold in particular leached readily. Subsequent drilling of the gossan (using triple core barrel technology for better recovery of the easily ground core) indicated 1,536,363 tonnes (1,690,000 tons) with an average grade of 1.05 g/tonne (0.037 oz/ton) gold and 42.13 g/tonne"

Jan 1, 1993

By Ted J. Williams

Underhand cut and fill mining methods are used at the Lucky Friday, Stillwater, and Galena mines in the western US in an effort to safely mine in difficult ground conditions and as a primary mining method where access below the ore is limited. The method has evolved at each mine to meet the unique situations associated with their milling procedure and mine layout. Details of the operational aspects of the backfilling and mining cycles at each mine are presented in this paper, accompanied by a summary of the mechanical properties of the backfill and its in-situ geomechanical behavior.

May 1, 2007

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 Michael Young, Peter Allum, Mingwei Gao

"Tough economical conditions and high grade but fine-grained ore processing have forced the mining industry to look for more efficient processes. Isa Mill Technology for ultra-fine and fine grinding is one such process employed at several mining operations in Australia including Mount Isa Mines Limited in Australia. Mount Isa Mines is a business unit of MIM Holdings Limited. MIM is an Australian-based international mining and mineral processing company with around 8000 employees worldwide. Major products include copper, gold, zinc-lead-silver, coal and technology sales.The Isa Mill is a horizontal stirred mill with sizes up to 3 m3 chamber net volume and 1 120 kW installed motor. It was jointly invented by Mount Isa Mines of Australia and Netzsch Feinmahltecknik GmbH of Germany for ultra-fine and fine grinding duties in the minerals industry. Isa Mill operations started in 1994 at the Mount Isa Mines Leadzinc Concentrator and then at MIM’s McArthur River Mine in 1995. These Isa Mills have been used to liberate sphalerite and galena at Mount Isa and silica at McArthur River by grinding to less than 7 micron.This paper discusses the Isa Mill Technology and reports on the metallurgical performance of the Isa Mills at Mount Isa Mines, including work done over the last 9 years to improve mill design, process efficiency and maintenance, which has resulted in the current state-of-the-art Isa Mill Technology.INTRODUCTIONThe current leadzinc deposits at Mount Isa Mines (George Fisher, Hilton and Isa) have an average grade of 10.5% zinc, 7.2% lead and 165g/t silver. Fine grinding, in particular in the zinc retreatment circuit requiring a milled product P80 of 7 micron, is essential to treat the ores from the Mount Isa Mines deposits. Every one micron size reduction in the zinc retreatment circuit below a P80 of 10 micron improves the overall plant zinc recovery by 1%, resulting in an increase in revenue of about 1 million dollars per annum."

Jan 1, 2002

By K. Leung, J. E. Udd, L. B. Geller, F. Kitzinger

"Sixteen miners died tragically at the Paymaster gold mine in Timmins, Ontario, in February 1945 when a badly corroded hoist rope broke. The investigation of the Royal Commission that followed arrived at a number of recommendations (The Legislative Assembly of Ontario, 1947) aimed at avoiding future disasters of this kind. One consequence was the development and legislated use in Canada, several decades ago, of powerful electromagnetic (EM) instruments for the non-destructive testing of mine shaft wire ropes. The authors have been involved for many years in the design, production, and testing of EM instruments (Geller and Udd, 1990, 1992; Geller and Kitzinger, 1991; Geller et al., 1992). Since the mid-1990s, particular attention was paid to the design and operational results obtained from the computer controlled portable MagnographTM II wire rope tester (Geller et al., 1995, 1998).In the present paper, the authors summarize further hardware- and software-related developments of this instrument. Further, an account is given of the results obtained from the most recent design known as the Perma- ScanTM testing system. This is also a computerized dual-function system. In it, however, the sensor head is designed primarily, if not solely, for permanent installation and for remotely controlled operation. This represents a basic departure from traditional designs, which were intended for ad hoc temporary installations. The remote-controlled instrument described in this paper has now been in operational use for more than four years."

Jan 1, 2003

By P. G. Semple

"In January 1985, Equity Silver Mines Limited began operation of a cyanidation circuit to scavenge precious metals from the flotation tailings. At present, this process is treating 270,000 tonnes of tailings per month and is recovering in excess of 0.20 grams of gold per tonne. To obtain these results Equity is operating a carbon-in-leach circuit that utilizes pressure stripping, zinc precipitation acid washing and thermal reactivation. A cyanide destruction circuit is also required to minimize the deleterious effects on reclaim water in the flotation stage. This paper describes the existing scavenger plant, and details the start-up problems encountered and the modifications made to correct these problems.INTRODUCTIONEquity Silver Mines Limited , a 68% owned subsidiary of Placer Development Limited , is located 38 km southeast of Houston in north central British Columbia. The geographic location of Equity Silver Mines is shown in figure #1. In September 1980, production first began with the ore being supplied from the Southern Tail open pit. In March 1984, the Southern Tail deposit had reached its economic pit depth, and since then ore has been supplied by the Main Zone pit the gold mineralization in the Main Zone is less refractory than the Southern Tail and cyanidation of the flotation tailing appeared to be a viable alternative.An extensive test program was undertaken and the results confirmed that considerable gold and silver values were amenable to cyanide leaching. A feasibility study showed that these values could be economically recovered and the detailed engineering work began."

Jan 1, 1987

By Jack Zhang, Yunguo Tang, Baodong Zhao

"Rare earth elements (REEs) have numerous key applications in both traditional and advanced technologies. A shortage of some critical REEs is expected due to the discrepancy between the REE abundance in REE deposits and the REE demand from the market. For example, Neodymium, Europium, Terbium, Dysprosium, Erbium and Yttrium are expected to be in short supply. REE recovery and separation from secondary resources such as uranium wastes, heavy mineral sands, and recycled materials can balance the shortfall in a cost effective way.The Saskatchewan Research Council (SRC) is engaged in the development and commercialization of complete REE recovery and separation technologies in Canada. One of SRC’s newest developments is the design and commissioning of a heavy rare earth (HREE) separation pilot plant. The pilot plant uses hundreds of stages of solvent extraction (SX) to produce high purity individual HREEs from both primary and secondary resources.This paper presents the design of an HREE recovery process for the particular case of uranium processing wastes. The separation results of a group separation are reported and discussed, as well as the issues and the challenges of the development, commissioning and operation of the continuous SX pilot plant.IntroductionSignificant amounts of strategic specialty heavy rare earth elements (HREEs) are found in uranium wastes in Saskatchewan. It estimated that about 47 tonne/a of heavy rare earth element oxides (HREO) including 27 tonne/a of Y2O3, plus 6 tonne/a of Sc2O3 are in the raffinate of every uranium mill for potential recovery. Since the HREEs are already in the raffinate, cost effective HREE production is promising in Saskatchewan.Selective precipitation including nutraulization, oxalate and double-salts precipitation, as well as sulfide precipitation, ion exchange (IX) and SX are commonly used technologies for the recovery and purification of REE solution. REE oxalate precipitation is an effective technology to remove Fe, Al, Ca, Si and other impurities by taking the advantages of the solubility difference between oxalates of REEs and impurities in acidic solution (Xu, 2005)."

Jan 1, 2017

By Neri Roux, Chris Budgell, Allan Cramm, Leo Cheung

"Anaconda Mining Inc. is investigating potential improvements and expansions to their operating plant located on the Baie Verte Peninsula in Newfoundland. An extensive batch and continuous bench scale testing program was launched to investigate the efficiency of cyanide destruction under different conditions in order to improve tailings handling. The primary objective of the cyanide destruction study was to apply new technologies to develop a novel cyanide destruction system.Effluent and slurry from Anaconda Mining Inc.’s Point Rousse Project was received at RPC where test work was conducted. Various sodium metabisulfite (MBS) dosages were evaluated and the use of utilizing ozone and ultra violet (UV) light to oxidize cyanide was investigated. All the data was evaluated and mass balances were compiled to develop several flowsheets. Overall encouraging results were found using a combination of ozone and MBS.IntroductionAnaconda Mining Inc.’s Point Rousse project includes an operating gold processing plant located on the Baie Verte Peninsula in Newfoundland which is in the process of improving and expanding. This plant comprises of milling and flotation followed by cyanide leaching in order to extract the gold. The residue from cyanide leaching is filtered by drum filters prior to being clarified for the Merrill-Crowe process. Once the gold has been recovered by the Merrill-Crowe process the effluent is filtered by filter presses and the resulting filtrate as well as the solids from the drum filters are detoxified prior to being pumped to the tailings pond along with the flotation tailings.The entire process is very dependent upon the efficient destruction of cyanide in the effluents and successful tailings handling. Substantial amounts of effluent are delivered to tailings ponds after gold extraction which could create environmental problems if the regulations are not met. Environmental regulations stipulate that final effluents contain no more than 1 mg/L Total CN.The detoxified tailings of the Point Rousse project are produced by the INCO SO2-Air circuit depicted in Figure 1. These detox tailings contain 10 mg/L Total CN at that point of the circuit and this was selected as the target to be matched while reducing overall MBS consumption rates from 3.2 g/L per minute. Prior to detoxification, the filter press tailings contain 520 mg/L Total CN while the drum tailings contain 29 mg/L Total CN."

Jan 1, 2017

By Mostafa Benzaazoua

Les remblais en pâte cimentés sont de plus en plus utilisés dans les exploitations minières souterraines. Une autre alternative d?utilisation du remblai en pâte consiste à le pomper et à le stocker dans des empilements de surface. En plus d?avoir des avantages d?un point de vue de stabilité physique des ouvrages, le remblai en pâte cimenté en surface permettrait également de stabiliser les contaminants dans la matrice du remblai à l?aide du processus de solidification et de stabilisation. Dans cette étude, des remblais en pâte constitués d?un résidu minier sulfuré renfermant beaucoup d?arsenic et de différents liants ont été testés afin d?évaluer la stabilisation des contaminants dans la matrice de remblai. La méthode utilisée pour évaluer la stabilisation et la solidification des contaminants est le test de lixiviation en extracteur de Soxhlet. Les résultats géochimiques issus de ces essais ainsi que la caractérisation chimico-minéralogique des remblais lixiviés ont été analysés pour comprendre les phénomènes chimiques présents dans les remblais durant le temps de cure. Les résultats obtenus montrent que les sulfures présents dans les remblais étudiés (pyrite FeS2 et arsénopyrite FeAsS) s?oxydent et provoquent la dissolution des hydrates les plus vulnérables (dissolution de la portlandite Ca(OH)2 et/ou décalcification des gels CSH). Le calcium produit permet de précipiter les sulfates (essentiellement sous forme de gypse plus ou moins hydraté) et l?arsenic sous forme d?arséniates de calcium plus stables. Les différents liants utilisés donnent des résultats différents en termes de stabilisation et de solidification qui seront discutés dans cet article.

Nov 1, 2002

By J. Chlopas, D. J. Barratt, M. V. Sharp

"This paper describes the modifications made to the Fox Mine copper concentrate bin in order to obtain a continuous flow condition. The design of these modifications is based on test results obtained on Fox Mine concentrate using the flow factor testing machine in the research facilities of Cominco at Trail, B.C.The original design consisted of a cylindrical steel bin on a concrete slab with two slot-discharge openings. Based on predictions of the maximum mass flow hopper angle for conical and wedge shaped hoppers for the concentrate on various potential bin lining materials, Ultra-High Molecular Weight (UHMW) Polymer was selected as a liner.Using the recommended angles for conical and wedge shaped hoppers, the profile of the bin base was changed to suit the existing slot openings.The initial method of fastening the liner resulted in failure of the connections. Subsequent modification to the zinc concentrate bin fastener system proved satisfactory and it has now been in operation for over one year without any separation of the lining material.Utilization of flow testing procedures on concentrate samples has demonstrated that proper design of storage bins or hoppers to achieve continuous flow can be incorporated into the design of new plants."

Jan 1, 1978

By Bern Klein, Malcolm Scoble, Justin Widdifield, Andrew Bamber

"It has been suggested that the pre-concentration of ore underground can bring positive economic and environmental benefits to underground mining, particularly at extreme depth. The integration of mineral processing systems for coarse waste rejection and disposal into the underground mining environment has a substantial impact on the economics and operation of the mine. A case study for the integration of underground pre-concentration at Falconbridge’s Thayer Lindsley and Fraser Copper operations in Sudbury, Ontario is discussed, with particular focus on ore evaluation, system design, integration, and impacts on the operation. Conclusions as to the overall feasibility and potential impacts of underground pre-concentration are presented.INTRODUCTIONObjectivesA scoping investigation has been conducted for Falconbridge Ltd on the Fraser Copper Zone and Thayer Lindsley mines in order to develop a better understanding of the operations, and to do a preliminary evaluation of the potential for pre-concentration of the ore underground. The objective was to develop a conceptual design and evaluation of a pre-concentration system for each site. The results are to be used as the basis for a more detailed future study.Underground Pre-ConcentrationThe pre-concentration of ore to reduce the quantity and improve the quality of material transported to the processing plant is not a new concept and has been in practise at several mines including the American Zinc Company in Mascot Tennessee (Munro et al, 1982), the Sullivan Mine in British Columbia and presently at Xstrata’s Mt Isa lead-zinc mine in Australia, as well as at several PGM mines operating in the South African Bushveld. For each of these mines, a high degree of waste rejection was achieved at a coarse particle size with good metallurgical recoveries. The benefits arising from the surface pre-concentration of ore are well documented in the literature (McCullough et al, 1999; Miller et al, 1978; Munro et al, 1982; Schena et al, 1990; Sivamohan & Forssberg, 1991)."

Jan 1, 2006

By Ning Shi

This paper suggests an alternative design approach for an innovative shovel dipper, for use in ground conditions where cutting of virgin ground rather than scooping of blasted material is required. Not only does the new design have an optimized dimension ratio (width:height:depth) and attachment arrangement (angle, position), but also a non-linear pro¯le in 2D and 3D. The approach is based on the simulation of a shovel's duty cycle to verify a pilot dipper model. In order to achieve a realistic simulation that could be used to evaluate a dipper design, the model is e®ectively a descriptor of actual shovel activity under soft ground conditions. The shovel geometry, motion and operation, with an emphasis on digging and dumping kinematics and dynamics are the principal elements of the simulation. The simulation considers a fresh face location, repeating tucking, digging and dumping swing motions within the geometric range of the machine, ending when no more face material remaining within reach without re- positioning. The simulation yields digging force, friction force, trajectory, ¯ll time, ¯ll factor, etc, which may be integrated into two basic considerations: power draw (output) and volume delivered (production), as indicators of dipper performance. The simulation has been used as a tool to modify an existing dipper design, prior to looping further simulation cycles. Ultimately, an optimized or totally-new-concept shape is realized. A prototype dipper as a fractional scale model will be built to verity the performance under actual mining conditions.

May 1, 2004

By W. Bullen

A hypothetical economic model has been developed for diamond projects in the Canadian Arctic using data from recent exploration and mining projects. The model reflects economic conditions applicable to the diamond mining industry in the Canadian Arctic at the present time. The economic model captures pre-production expenditures, production data, and post-production costs. Before- and after-tax cash flows are derived from the data along with the relevant economic criteria. From the corporate perspective, the model provides guidance concerning the minimum size and/or in situ value per tonne requirements of targets being sought in order to ensure economic success and predict exploration and development expenditures. From the government perspective, the model provides an indication of income and mining tax revenues that can be expected from a particular diamond project. The model shows, on average, diamond projects in the Canadian Arctic are expensive to explore for and develop, but are economically robust under the present conditions. They generate great economic return for mining companies and significant amounts of tax revenue for governments. The fact that diamonds can be transported directly from the minesite by air makes them particularly attractive targets for mining companies that operate in the Canadian Arctic.

Jan 1, 2006