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By K. Reipas

"Westmin Resources Ltd. operates the 3300 TPD H-W underground copper/zinc mine on Vancouver Island. Ore storage underground is handled in a 6000 tonne coarse ore bin and a 3000 tonne fine ore bin. Both of these bins have experienced significant wear since excavation and construction in 1985. Wear problems have included both deteriorating rock walls as well as worn out steel liners and concrete at the discharge points from the bins. Extensive rehabilitation work was completed in 1993.The basis o/this paper is the rehabilitation work done on the coarse ore bin. The design and installation of ground control measures are discussed. The bin access methods used to allow the work to proceed quickly and safely are also presented. This involved the use of a Tekfoam safety bulkhead to protect workers.IntroductionMine DescriptionThe H-W mine was commissioned in 1985. Mine access is by vertical shaft with most production areas at a depth of about 500 m. Host rocks are composed of andesite and rhyolite. Mine capacity of 3300 tonnes per day is achieved mainly by longhole open stoping methods, complemented by room and pillar mining. Metals recovered from the massive sulphide ore are copper, zinc, gold, and silver. Mineable reserves at January I, 1994 were 9.7 million tonnes."

Jan 1, 1995

By Marc C. Bétournay

A number of successful proof-of-concept projects have been carried out to replace conventional power application, such as diesel and rechargeable batteries, in underground mine vehicles. This has led to the development of the world?s first fuelcell production vehicle, a mine locomotive. A mine loader project has also started and several other projects are planned. These projects are providing the mining industry with the required information to make this technology shift possible. The application of fuelcell power will yield several important benefits such as the elimination of underground diesel emissions, significant reduction in the primary extraction?s sector greenhouse gas emissions and support for a more productive scenario. This article reviews these successes, discusses ongoing and potential projects and presents the technology application benefits that could be possible for mining operations.

May 1, 2003

By Yan Jie

A series of production technologies are described for gold recovery from complex gold concentrate blended with copper concentrate treated in the SKS smelting process comprising: 1) Feed preparation and proportionate feeding of complex gold concentrate and copper concentrate; 2) SKS smelting gold recovery operation and process control technology developed based on reaction mechanism, process simulation and slag formation optimization study; 3) a dry-process quenching arsenic collection technology developed during de-bottlenecking severe restriction of SO3 in the off-gas on As collection system by suppressing and eliminating SO3 in off-gas as a result of optimizing SKS smelting process conditions and spraying caustic soda absorbent so as to reduce off-gas dew point temperature; 4) electrorefining of impure anodes; 5) technology for recovering such precious metals as Au, Ag, Pt, Pd, etc. from high-Sb copper anode slime produced as a result of gold recovery from complex gold concentrate by using SKS smelting process. INTRODUCTION Gold concentrate resources in China are mainly found in Shandong province, Henan province and the Inner Mongolia Autonomous Region, etc. Currently, recovery of gold is based on pre-oxidation (roasting) cyanide leaching process. This process produces a large amount of cyanide-containing wastewater, cyanide leaching residue and relatively high SO2-bearing flue gas during production, which can cause increasingly more serious environmental pollution issues. Besides, this process route suffers from a relatively low precious metals recovery (70–80%) found when treating refractory gold concentrate and carbon-bearing gold concentrate. These issues have severely restricted the development of the precious metals processing industry in China.

Jan 1, 2019

By J. Ouellet

"ABSTRACTA brief background on in-situ testing of mine backfill, as well as pressuremeter testing is briefly described, and results from an in-situ testing on paste backfill are presented. A series of self-boring pressuremeter tests were done from the top of a backfilled stope in an underground mine. The tests were conducted along a 20-metre vertical line in the centre of the stope. Some 14 tests were performed along this depth. The instrument used was a Camkometer built by Cam Insitu, Cambridge. The instrument proved to be efficient and reliable for underground testing in a cemented paste backfill. The testing program was conducted within the planned schedule with a high success rate. The test done in this study permitted the measurement of paste backfill strength, stiffness and in-situ horizontal stress within the backfill. RésuméUn bref historique des essais in situ dans le remblai minier est présenté. L’essai pressiométrique est décrit succinctement et des résultats d’une campagne d’essai dans un remblai en pâte sont présentés. Un programme d’essais au pressiomètre auto-foreur a été réalisé à partir du sommet d’un chantier remblayé sous terre. Les essais ont été réalisés le long d’un ligne vertical d’environ 20 mètres pour un total de 14 mesures. Le Camkometer de la firme Cam Insitu de Cambridge a été utilisé. Cet instrument s’est avéré efficace et fiable pour tester le remblai en pâte cimenté sous terre. Le programme d’essai s’est déroulé à l’intérieur de l’échéancier prévu avec un taux de réussite élevé. Ces essais ont permis de déterminer la résistance, la rigidité de ce remblai ainsi que les pressions in-situ prévalant dans le remblai."

Jan 1, 2000

By F. Chiesa, Jeremy Carignan, B. Duchesne, D. Levasseur

"Aluminium A206 (AlCu4) is one of the strongest aluminium casting alloys with tensile properties approaching those of ferritic ductile iron. If the specification on the silicon content (< 0.05%) is easy to achieve during alloy ingot production, it is not the case in a foundry, where returns are used which are not perfectly cleaned from the silicate containing molding sand (Olivine). In alloy A206, the Si content is controlled in order to avoid the formation of a low melting point intermetallic phase (such as phase Q Al5Cu2Si6Mg2); these phases will melt during the solutionizing heat treatment to which alloy A206 must be subjected to develop its outstanding mechanical properties. This incipient melting may deteriorate the mechanical properties of Alloy A206 if the solutionizing treatment is applied at the standard temperature of 530°C.In the present study, a lower temperature solutionizing (520°C) was applied to a high Si content 206 alloy in order to reduce or eliminate the possible incipient melting. This was carried out on a complex shape industrial casting weighing 14 kg (31 lb) and 560x410x250 mm (22x16x10”) in size poured in aluminum 206 with a high silicon content (0.22% vs 0.05% max for alloy A206). Twenty ASTM E8 subsize tensile specimens were excised from two locations in the casting in order to compare the tensile properties for the two solutionizing temperature used (530 and 520°C). Optical and SEM microscopy allowed to investigate the causes of the differences in the properties observed between the 2 zones of the casting studied for 3 different heat treatments. INTRODUCTIONIn spite of their “textbook” outstanding mechanical properties (Up to twice the strength and elongation of the widely used A356 alloy), aluminum-copper alloys of the 2xx series are seldom used because of their propensity for hot tearing [Li, 2011], the segregation of copper [Cho, 2003], and their sensitivity to stress corrosion cracking [Jean, 2009, p. 113)]. Also, because of their wide freezing range and high thermal conductivity, a wide mushy zone makes feeding difficult, unless strong temperature gradients are created by liberal use of chills and risers in the critical zones of the part. Because they are prone to hot tearing, grain refining of Al-Cu alloys is particularly important, titanium playing a major role in the process [Sigworth, 2003]; grain refining has also been shown to be beneficial to fatigue strength [Jean, 2009, p. 103]. The practical basis of foundry practices pertaining to these alloys is outlined in an AFS webinar [Weiss, 2014]."

Jan 1, 2016

By E. G. Joe

"The continuing increase in costs for power and fuel are affecting significantly the cost for milling of Canadian ores. In order to ascertain the scope and source of energy consumption in Canadian mills for further energy conservation opportunities, CANMET, in cooperation with the Canadian Mineral Processors carried out a detailed survey on the metallic mineral processing plants. Sixty-seven mills representing almost 300 million tons of annual capacity participated in the survey. The results indicated that in general, copper and iron ore mills, representing the bulk of the tonnage, consumed relatively low levels of energy per ton. Nickel-copper, zinc-copper and lead-zinc ore mills were moderate in energy consumption, while uranium and some copper-lead-zinc mills reported much higher energy consumptions due primarily to the increased heat requirements of the ore pulp. While the plant heating costs varied somewhat with the location in Canada, it was apparent that the lowest heating costs were achieved by those built with proper insulation and energy conservation design. If the cost per million British Thermal Units is taken as $2.00, the mill energy costs generally ranged from 40¢/ton up to $1.20/ton.IntroductionEnergy consumption in milling has always been of significant interest to Canadian mineral processors who traditionally calculate their milling costs down to pennies per ton. Even the measure of an ore's grindability is expressed empirically by Bond in kilowatts hours per ton milled. Some of the mills located in isolated areas were obliged to generate their own electrical energy from fossil or petroleum-based fuel at a cost substantially higher than that obtainable from captive or public hydro-electric installations. These mills practiced energy conservation long before the advent of O.P.E.C. energy cost inflation. One example of this was the use of electric boilers to produce process and heating steam during off-peak electrical load periods."

Jan 1, 1978

By H. B. Lumsden

This paper is intended to deal merely with the commercial development of some of the principal non-metallic mineral resources in the three prairie provinces- Manitoba, Saskatchewan, and Alberta. Coal is not included in this summary. Building Stone First and foremost, mention may be made of the building stone now being produced at Tyndall, Manitoba. This is a mottled limestone and is declared by experts to be one of the finest building stones in America, both as regards durability and appearance. It has been used very extensively both for exterior and interior work, not only in western Canada, but also in the principal cities as far east as Montreal. The stone is the "&apos;Upper Mottled Limestone", which forms the summit of the Trenton (Ordovician) strata in the Lake Winnipeg basin. Quarries are at present being operated at Garson and Tyndall . The area where this stone is known to be available extends in a north and south direction for a distance of three miles, and the main productive ridge is probably about one half mile wide. The outlook for the future of the industry is extremely promising, as the stone is becoming increasingly popular in Eastern Canada, more particularly for interior work.

Jan 1, 1928

By P. J. Adams

Environmental regulations require means for controlling emissions of SO2 NOx and particulate when burning coal. The combustion of coal in limestone fluidized beds is one of the most promising techniques for the necessary reduction in emissions. Fluidized-bed firing, furthermore, offers potential economies in capital equipment. The world&apos;s largest steam generator applying fluidized-bed techniques was built under the sponsorship of ERDA and installed in Rivesville, West Virginia. This paper describes the design and discusses the start-up and development difficulties which were experienced during the period from initial operation to current readiness for commercial operation. Other developments leading to utility and industrial fluidized-bed steam generating equipment are reviewed. The future potential of this promising technique is discussed.

Jan 1, 1979

"Dry crushing trials at pilot scale have shown that the IMPTEC Super-fine Crusher has the capacity to generate ultra-fine products from hard mineral assemblages presenting at either coarse or fine feed sizes. The super-fine crusher was introduced at the 27th International Mineral Processing Congress in Santiago Chile, with results from a range of duties, which demonstrated the crusher’s potentially expansive operating scope. This paper focuses on current preparations to progress the technology from pilot scale to commercial scale within a concrete production plant, where lead blast furnace slag will be crushed to ultrafine sizes to generate an active silica product for use as a supplementary cementitious material, which can replace Ordinary Portland Cement. A key objective of the operation is to demonstrate an economical route to reducing the cost of concrete production, improving concrete quality and reducing greenhouse gas emissions. The paper also highlights the potentially key contribution super-fine crushing can make to the long-term viability of iron ore beneficiation by simplifying comminution flow-sheets and reducing operating costs. There is every indication that the technology has the potential to feature universally in metalliferous and industrial mineral flow-sheets. INTRODUCTIONToday’s IMPTEC super-fine crusher is the successful end product of development work over 19 years and is the third particle size reduction device conceived, built and tested over that time. The concept evolved as engineering design progressively developed a mechanism capable of harnessing a highly efficient combination of fundamental particle breakage mechanisms. Early development trials at pilot scale indicated that super-fine crushing had the potential to establish a wet or dry, media free, low energy route to ultra- fine products from hard mineral assemblages. Having achieved some impressive results from open circuit pilot tests on fly ash and granulated blast furnace slag it became clear that the cement industry may well provide opportunities to apply the technology commercially. Following expressions of interest from local cement and concrete plant operators, IMPTEC negotiated an agreement to undertake commercial trials with a SFC 350 super-fine crusher installed on site at a concrete supply plant in South Australia. Super-fine crushing scope was recently expanded following further expressions of interest from research groups involved in the processing of iron ores. Pilot trials are progressing in these areas."

Jan 1, 2016

By L Mariani, G. Mendoza-Suarez

In this investigation, TiH2 powders were coated with copper and nickel by electroless plating to delay hydrogen evolution. Copper-coated samples were found to have a mixed acicular (2D growth) and cauliflower (3D growth) morphology whereas the nickel-coated samples had a cauliflower morphology. Examinations of the coated powder cross-sections revealed that the coating thickness ranges from 0.2 µm to 4 µm. Uncoated areas on the powder surface and coating flakes unattached to TiH2 particles suggest poor adhesion between the coating and the substrate. The phase transformation undergone by the TiH2 during dehydrogenation was studied in samples taken at intermediary points in the heating cycles and examined by XRD. The findings reveal that as the powder is heated from room temperature to 800°C, it changes from TiH1.971 to Tiu and to aTi. Differential Thermal Analysis (DTA) was performed to study the effects of the coatings on the temperature of hydrogen release. It was found that increasing the number of plating iterations, and therefore the thickness of the coating, creates a significant shift in the temperature of gas release.

Jan 1, 2006

By D. Marcotte

The Rock Quality Designation (RQD) is a standard scalar measure of rock quality used in common rock mass classification systems (e.g. RMR, Q system). RQD is measured along diamond drill holes. RQD interpolation between holes is nontrivial. Despite the inherent limitations of drill hole data and the local complexities of structural geology, it is often the only information available for mining and major civil engineering projects. Therefore, maximizing the usefulness of this data is warranted. We derive a correction for directional effects that help reduce the bias and improve the accuracy of the estimations. The correction is derived with the aid of numerous simulations. It relies on simple information, the angle between the joint normals and the borehole axis (JO). A reference direction is identified as the borehole direction with smallest JO. A multiple linear regression model based on JO statistics in the various boreholes defines the correction model. The corrected RQD values are then interpolated. It is shown the method enables reducing the bias on RQD estimation by 50% and improves the accuracy of the estimates by 30%. The corrected RQD values show stronger spatial continuity than the raw values. The benefits of estimating the RQD indirectly by using joint frequency measures are also assessed.

May 1, 2003

By Yve Fourmanoit

"This paper discusses the exploitation of shallow underground deposits in a very altered geological environment. The methods, their adaptation to local conditions, their evolution, dilution control and recovery of mineral reserves will all be dealt with.The recovery of the B zone crown pillar under 40 m of till that was originally saturated with water, is of particular interest.Future underground development and production start-up of the A-2 zone, organization of mining operations, mechanical services, group incentives and safety practices will also be given.IntroductionThe underground deposit of B zone is not very deep. A 300 m shaft provides access to the mine. In addition , exploitation sublevels are developed every 20 m and are linked by a service ramp. The overburden located on top of the deposit is 40 m thick and is composed of a very dense till.A detailed work plan was initiated to permit mining under the overburden. To do so, it was imperative that efficient methods be developed. At a time when an accident at the Belmoral Mine shook the mining world , it was a task to convince provincial authorities that it was safe.While B zone was being mined , development began in the A-2 zone deposit which has recently been put into production (Figs. 1 and 2).The intention of this paper is to provide an outline of the mining method s and their particular aspects. To do so, some of the mine services are described and a brief outline of the under ground department is provided."

Jan 1, 1990

By D. W. Boydell

The response of reclaimed gold tailings to acid leaching was investigated in the laboratory, followed by a pilot-plant program in which the operations of CCD, CIX and SX were tested with plant feed material. These results formed the basis for the design of the extension to the existing uranium plant at Blyvooruitzicht Gold Mine, commissioned in July 1977. This circuit consists of slimes-dam reclamation by bucket-wheel excavator at a rate of 100,000 t solids per month, acid leaching in pachucas, a five-stage CCD washing section, two parallel C1X absorption columns and two elution columns, SX and an ADU precipitation section. Barren solution is recycled to the CCD section as wash and to the repulper at the slimes dam. The performance of the plant during the first year of operation is compared with the predictions on which the plant design was based. Rated capacity was achieved within three weeks of start-up at a nominal dissolved uranium recovery in the ion-exchange section of around 98%. Owing to recycle, the over-all recovery in the ion-exchange and solvent extraction sections is somewhat higher than this figure.

Jan 1, 1979

By L. Garrigues, M. Jarvis, M. Halhead, O. A. Bascur

"Large variability of ore types, escalating variables operating costs and increased throughput require large investment in sensors and systems in mineral processing operations. Mining and mineral processing plants collect and manage more data than a small city with much in real-time. The data is changing rapidly as internal and external conditions evolve. As corporations buy and sell assets, and reengineer their staff, the structure and tools that were used to understand this data is lost. This results in significant deterioration in the ability to maintain a smart operation. When data is recognized as a critical asset and managed as part of an infrastructure, it become a key enabler to help transform the entire operations. In many situations, all partners in business collaboration—such as join ventures, contract manufacturer, expert service providers, and operations and maintenance companies—need access to production and asset data. The emergence and maturation of Cloud technologies make it possible to easily connect the plants to external equipment suppliers and operational support service.This paper will share examples of how mineral processors have adopted new data strategies such as self-service business intelligence, cloud computing and internal/external collaboration.INTRODUCTIONOne of the main challenges in mineral and metallurgical processing plants is effective energy and water management. The lowering of ore grades requires higher throughputs while the ores are getting more complex with variable mineralogical compositions. Electrical energy supply is becoming a restriction in many countries. Rising water management costs has a direct impact on the profitability of the operations. Grade recovery versus energy consumption in copper production for both open pit and underground mines has been described by Fuerstenau (2001). Comminution uses over 55% of the energy to produce nonferrous metals while other operations require much less energy (Nelson, Richins, & Lelinski, 2013)."

Jan 1, 2016

By A. I. A. Salama, M. W. Mikhail

"The existing methods of block diagram manipulation and vanishing variable for flowsheet simplification used in coal and mineral processing circuit evaluation and optimization cannot be easily implemented on digital computer.The signal flowgraph technique is proposed to represent and simplify determination of the relationship between intermediate or end variable and the feed in the flowsheet. Typical and existing circuits are used to demonstrate the application of the proposed technique which can easily be implemented on digital computers.IntroductionRecently there has been much interest in the analysis and optimization of coal and mineral processing circuits to assist in the pre diction of coal and mineral processing plant performance. The block diagram and the vanishing variable were introduced and utilized in the analysis of plant flowsheet. Although the block diagram approach is useful, it requires manual manipulation of the circuit block diagram which may present difficulties in the situation of complex circuits. Moreover, it may not be easy to implement on a digital computer.In this paper, the signal flowgraph technique is proposed to represent the circuit flowsheet and to simplify the determination of relationships between intermediate or end variables (fractional mass) and the feed for any coal and for any mineral processing circuit comprising size and density separators. These relationships are utilized in the analysis and/or optimization of the circuit. The proposed technique is illustrated by considering typical and existing circuits."

Jan 1, 1987

By Pierre Antoine Dhaiti, Gilbert Sergerie, Michel Dagbert, Jean-Maurice Brodeur

"Quality of iron ore is generally determined by several factors which can be correlated or independent. Among these f actors, we generally find per cent iron, silica, magnetite or hardness. Forecasting the short- and long-term fluctuations of these f actors in the future pit is an important feature of mine planning in these deposits. Computer simulation provides a realistic answer to these questions. It allows to generate values for the most important quality features of each shovel load with the proper correlations between them as well as between one load and the next being fully reproduced. Then different sampling schemes f or grade control or blending facilities can be examined on the simulated data. The mechanics of the simulation procedure and its potential applications are described in an example.IntroductionThe purpose of this paper is to illustrate the use of in-situ grade simulation in the planning o f the grade control in an iron ore min e. More precisely, given a production unit of given size, we need to know how many samples have to be collected in that unit so that we ca n recognize its grade with a reasonable precision. Conclusions that we would like to arrive at are of the type: with 4 blasthole samples we ca n get the iron grade of a 10,000 ton bloc k with less than a ± 2% Fe error 95% of the time.The approach t hat we take to solve this problem is simulation. We simulate the grade of samples and the grade of the block that contains these samples. We repeat the simulation for hundred s o f blocks. By comparing the sample grade with the block grade in each case, we determine the actual number o f blocks where the difference sample-bloc k is less than a given limit."

Jan 1, 1983

By Hagen B. Schultes

"Refratechnik, a leading German refractory company, acquired a majority shareholding in Baymag in 1979. This acquisition included the mining rights for a magnesite deposit of exceptionally high purity in the Canadian Rocky Mountains.The deposit, situated in the Kootenay region of southeastern British Columbia, is of Cambrian age and has ore reserves of 50 million m. t. of magnesite. The Baymag magnesite deposit is one of the purest in the world. The deposit was opened up and mining commenced in early 1982. Production of various caustic calcined magnesia products in a rotary kiln operation in Exshaw, Alberta, was started in mid-1982. The product application ranges from pulp and paper production, to the chemical industry, and to animal feed supplements. Since the end of 1983, Baymag has produced high-quality refractory grade fused magnesium oxide f or specialty applications in the steel industry.IntroductionAlthough magnesium is the eighth most abundant element in the earth and forms about 2.06% of the earth&apos;s crust, common knowledge about magnesium and especially magnesium oxide (MgO) as an industrial mineral is not widespread. The reason might be that, with the exception of magnesium metal as the element, magnesia products are not generally sold as final products to end-users, but rather are needed for the production of final products such as steel, cement, paper, etc. Therefore, some general comments are given about the different sources of MgO, the different products, world production and consumption , before Baymag specifics are addressed. Magnesium metal will not be discussed in this paper."

Jan 1, 1986

By E. Yan, M. Mankosa, E. B. Wasmund

Mechanical cells are the dominant unit operation in base metal rougher flotation applications worldwide. As economic demand for metals increase, and as the feasible ore grades decrease, the installed capacity of mechanical flotation units worldwide has greatly increased, adding significant capital and operating cost. One opportunity to improve this situation is to use fundamental knowledge to make the industrial flotation process more efficient. A key insight is that the flotation process can be optimized by dividing the processing of the pulp into two distinct fluidic environments; a collection cell where air and pulp mix in a highly energetic compartment, and a low energy gravity separation cell. This is the basis of the “2-stage flotation device” that has been patented by Eriez and marketed under the tradename StackCell™. Two industrial case studies will be presented to highlight the potential metallurgical and commercial advantages of the StackCell. In the first, a train consisting of three pilot scale StackCells (each 0.6 metre diameter) was run in parallel with a train of conventional mechanical cells in a major copper concentrator and benchmarked against a batch Denver test. In the second, the performance of a 3 metre diameter StackCell in a nickel sulfide cleaning application was benchmarked against a batch Denver test. The flotation kinetics observed in the StackCells were 2.4 to 2.9 times faster when compared with the lab Denver test. In the first case study, the kinetics of the StackCell was about six times faster than conventional mechanical cells. It is hypothesized that the efficiency improvement in kinetics is because of reduced “drop-back” during the froth recovery phase, which is reduced because of the reduction in the shear that is present in a conventional mechanical tank cell. This result suggests that a 2-stage flotation system can be used to reduce the working volume of flotation units by five to six times. This would allow operators to significantly reduce the size of their flotation lines for a comparable flotation objective. Some discussion will follow about the scale-up criteria, maintenance and operability issues, comparisons of layout, and possible cost savings. INTRODUCTION The solution that most equipment suppliers have offered to reduce the cost of mechanical flotation equipment over the last 30 years has been to increase the size of the flotation unit cell (Mankosa, 2017). For example, three 100 m3 machines with three smaller motors, mechanisms and control valves could be replaced with a geometrically similar 300 m3 with a larger version of each ancillary component. While there are some efficiencies and cost improvements to be gained by this approach, it does not take advantage of fundamental insights into the flotation process, and it does not represent a step-change in terms of process design or economic benefit for the customer. The advantage of the “bigger is better” approach is that there is past experience of incremental improvements by making cells larger and there is a well-established scale-up method, which allows practitioners to estimate equipment capital costs based on very simple laboratory test- work. A different paradigm, which is gaining interest rapidly is to use a unit operation in which it is easier to optimize the flotation process, which will be described in this paper. This approach is often referred to “2- stage flotation”. Because this approach is new, it is important to benchmark it against existing conventional technology and to demonstrate a robust methodology for sizing equipment and flowsheets. This paper aims to address these issues with two case studies.

Jan 1, 2019

By D. Racicot, T. Hanel, E. H. Chown

Over thirty plutons in the Chibougamau-Desmaraisville belt were examined briefly in the field and sampled, in addition to the few masses that have been studied in detail. The survey indicates that the intrusions may be conveniently grouped in four main categories, based on their time of intrusion. These are; remobilized basement domes, pre-kinematic intrusions, syn-kinematic intrusions and postkinematic intrusions. Basement domes, as exemplified by the Lappa rent Massif, are composed of migmatized tonalite-diorite gneiss that has undergone at least two periods of mafic dyke intrusion and at least three major deformational periods. The rise of the basement domes was accompanied by extensive mylonitization and the intrusion of syn-tectonic plutons. Pre-kinematic plutons, such the Chibougamau pluton, are diori te-tonalite in composition, and were intruded into the supracrustal pile and partly eroded before the main deformation of the belt. Syn-kinematic plutons occur principally as marginal intrusions bordering the belt (Barlow), or as discrete intrusions along structural highs (La Dauversiere), and are either hornblende monzodiorite or tonalite in composition. Post-kinematic plutons, such as Muscocho, are principally granodiorite and often porphyritic intrusions locally deforming the enclosing rocks. The close relationship between mineralization and high-level intrusions such as the pre-kinematic and some of the post-kinematic plutons is discussed.

Jan 1, 1984

By Jozef S. Stachula

"INCO Limited operates eleven under-ground mines in the Sudbury area. The mines are located on the rim of the Sudbury Basin, an oval with the axis in the range of 27 km and 60 km. The ore dips to at least 3000 m below surface. The ores are mined primarily for nickel and copper. Total ore production from underground is in excess of 55 000tonnes per day.Over 40 surface fans have been installed since the late 1960s. All of the fans are adjustable pitch, axial flow units. A major factor influencing ventilation design in the last 30years has been the introduction of diesel equipment underground. Volumes per fan have ranged from 60 m3/sec. to 330 m3/sec., with motors from 100 hp to 2500 hp.Fans of the axial flow type have been commonly used for main fan installations at Canadian mines for many years. The standard arrangement has been to mount these fans horizontally, i.e. with the fan shaft and the long axis of the housing horizontal. This is a natural arrangement for an underground fan, but for a surface installation, a vertically mounted fan has definite advantages.The surface area taken up by a typical vertical fan installation is generally about one quarter that of a horizontal fan of the same capacity (Rutherford, 1957). This is not a problem with isolated fans and fat surface out crop sites, but where the installation is to be near existing buildings, or where there are poor surface soil conditions, space and cost considerations greatly flavour vertical fans."

Jan 1, 1996