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By Shinji Shirakawa

The gold wire bonding technology is widely used for electrically connecting aluminum pads on IC devices to external terminal of semiconductor. In 1960?s, the tensile strength of gold bonding wire was about 100 MPa only. However, recently the wire with 300 MPa in strength has been developed. Since the gold bonding wire was started to use for IC package in early 1960?, the many types of gold bonding wire has been developing continuously in order to meet market?s needs, such as high density, small size and thin type of IC packages. Moreover, electronic equipments were used in automobile applications and also demanded good reliability under severe temperature environment. Thus Au-Pd alloy wire has been introduced instead of the wire with 4N(99.99wt%) purity gold to provide excellent reliability in Au-Al bond interface. The phenomena at Au-Al interface in the high temperature storage have been already explained by several studies as follows. There are five phases of inter metallic compound (IMC) between gold and aluminum. Just after bond gold ball on aluminum pad, Au5Al2 phase was formed and occupied almost all of IMC area. During high temperature storage test, Au5Al2 phase transformed to Au4Al phase, then this phase was corroded by Bromide (Br) ion that was isolated from molding resin. Thus the reliability between Au and Al degraded. In case of Au-Pd alloy wire, the concentrated palladium phase (Au-Pd-Al) was formed at the interface between Au alloy ball and Al pad. The Au-Pd-Al phase prevented from transforming between Au and Al, therefore Au5Al2 phase was hard to transform to Au4Al phase. Consequently the reliability at the interface between Au alloy ball and Al pad was less degradation. However, in recent study using several advanced analysis technique, Au4Al phase was found at the interface between Au alloy ball and Al pad same as the case of conventional gold wire (4N purity gold bonding wire). It was suggested that the formation of concentrated palladium phase (Au-Pd-Al) related the excellent reliability at ball bonding process.

Oct 1, 2003

By Kenta Suzuki, Toshiya Anami, Daisuke Shimosaka

"In an Al-Mn alloy heat exchanger fin stock, the effect of annealing conditions for as-cast and 0.1%Zr addition on recrystallization behavior is investigated using metallurgical analysis. Refinement of post-brazed recrystallized grains in fin stocks with Zr addition are suppressed for long-time annealing. In 0.1%Zr fin stocks, there was a decrease in the number of fine a-Al(Mn,Fe)Si dispersoids for pinning of sub grain and grain boundary. In addition, relatively homogeneous distribution of Al3Zr dispersoids was observed with increasing annealing time in as-cast. Homogeneous distribution of Al3Zr dispersoids can have a major effect on pinning of sub grain and grain boundary during brazing heat treatment. The homogenous distribution of fine dispersoids prior to brazing heat treatment is effective in causing the suppression of refinement of post-brazed recrystallized grain structure in aluminum alloy fin stocks.INTRODUCTIONAl-Mn based alloys are widely used as fin stocks in automotive heat exchangers because of their superior mechanical properties, braze ability, sagging and so on. In particular, coarsening of recrystallized grain structure is beneficial to avoid erosion, and achieve excellent sagging resistance (Lee, Yoon, Kim & Jung, 2002). For resisting grain coarsening, the alloys should contain a dense and homogeneous distribution of fine dispersoids to retarder crystallization (Humphyreys& Hatherly, 2004). It has been demonstrated that addition of Zr to Al-Mn alloys can shift recrystallization to higher temperatures because of the distribution of fine Al3Zr dispersoids in matrix(Pokoba, Cieslar& Lacaze,2012). According to Tohma, Asanoand Takeuchi (1987), coarsely recrystallized grain structure was obtained in 3003alloy with Zr addition after heat treatment. However, fine Al3Zr dispersoids are usually heterogeneously distributed because of segregation during casting and low diffusion rate of Zr in aluminum. Therefore, a homogeneous distribution of Al3Zr dispersoids can be achieved through long-time precipitation annealing(Jia, Hu, Forbord& Solberg, 2008)."

Jan 1, 2018

By M. S. Ünal

Creation of 3D model of coal seams is a tedious and time consuming operation. Computer aided 3D solid modelling of coal seams can be performed in a fast and detailed manner. However, in case of having tectonically disturbed coal seams where faults may be observed, expert opinion is necessary to decide the geometry of the coal seam. The aim of this study is detection of fault zones with computers by using drill hole data. Firstly, a digital database is generated by using the drill hole data. Surface models of the layers are produced by applying triangulation method on coal seam roof elevations. The generated surface is divided into small squares and consequently dip and dip direction values are calculated for each square. Variograms for dip and dip direction are determined and maps showing the variation of dip and dip direction are generated by using geostatistical methods such as kriging and co-kriging. Examination of disconformities observed on estimation maps created by kriging and co-kriging clearly reveals the extension of faults. The method used in this study is applied to detect fault lines of a known mine field. 3D solid modelling of the coal seam has also been performed by using conventional cross-section method. The results of both methods were in good agreement. Identification of major faults by using the method introduced in this study could certainly simplify 3D solid modelling of coal seams.

Aug 1, 2013

By Jeremy Breker

Cameco aligns its social and environmental responsibilities with its vision, mission and values. Environmental Leadership is established as a corporate objective that emphasizes the triple-bottom-line and a systematic approach to understanding environmental, social and economic issues, risks and opportunities. These are ingrained in the project culture, systems and processes and used to influence solutions derived by the project teams to achieve Cameco's objectives. This paper traces the organizational objectives from the early stages of a project through to implementation and turn over to Operations. A case study is used to demonstrate how an asset is influenced by Cameco?s strategy.

Aug 1, 2010

By A. Boucher, D. Marcotte

"Abstract- The accepted practice for the estimation of thin (2D) vein deposits recommends the use of the grade x thickness service variable (i.e., the accumulation). Grade estimates are obtained indirectly by the estimated accumulation/estimated thickness ratio. This practice stems from the varying support (thickness) problem and the resulting non-additive nature of the grade variable. We compare the actual performance of the direct grade estimation approach used by some practitioners to that of the indirect approach using accumulation. Our simulated and real data indicate that the direct approach is more accurate for point grade estimation where the grade-thickness correlation coefficient is positive (and vice-versa). Moreover, the relative gain of the direct method increases with the (positive) correlation coefficient. This finding contradicts common thinking that the indirect approach should be the preferred method where grade-thickness correlation is strongly positive. Also, for a given positive grade-thickness correlation, the relative gain of the direct method increases with the coefficient of variation of the grade and thickness. Résumé - L’estimation de veines minces (2D) minéralisées est normalement réalisée à l’aide de la variable auxiliaire épaisseur x teneur (i.e., accumulation). Les estimés des teneurs sont alors obtenus indirectement du rapport accumulation estimée/épaisseur estimée. Cette pratique découle du problème du support variable pour la teneur, l’épaisseur de la veine, qui fait que la teneur est alors une variable non-additive. Nous comparons les performances de l’estimation directe de la teneur, utilisée par certains praticiens, à celle de l’approche indirecte. Pour l’estimation ponctuelle des teneurs, nos données simulées et réelles indiquent une meilleure justesse de l’approche directe quand la corrélation teneur-épaisseur est positive (et vice-versa). De plus, le gain relatif de la méthode directe s’accroît avec la valeur de cette corrélation (positive). Ce résultat contredit l’opinion répandue que l’approche indirecte devrait être utilisée en présence de forte corrélation positive de la teneur et de l’épaisseur. Nous montrons également que pour une corrélation positive teneur-épaisseur donnée, le gain de l’approche directe augmente avec les coefficients de variation de l’épaisseur et de la teneur."

Jan 1, 2001

By Eric J. Grimsey, Don C. Ibana, David E. Grimsey

The segregation process as applied to nickel laterite ores involves the formation of gaseous nickel and iron chlorides which are subsequently reduced to form ferronickel on the surface of a solid carbon reductant. A fundamental study of the process has been carried out using limonite, nontronite and garnierite ores. The study highlighted the significant impacts that ore mineralogy and carbon addition have on the amount of nickel which is segregated rather than retained within the ore due to in-situ reduction. These important aspects affecting nickel recovery and the success of the process are discussed in this paper.

Jan 1, 2017

By Makhlouf Boubahziz

The HNIA field is part of the Tinrhert project which consists of developing 17 fields containing essentially gas with a few small rings of oil. It is considered as one of the main fields in this project in terms of its area and the number of geological structures that has formed it. It is a wide anticline of Cambro-Ordovician age, orientated NNE-SSW and located in the South-eastern part of Illizi basin. This structure extends from Alrar-center in the North, to the North of In Amenas in the South. The area is 1350 km2. The main reservoirs forming HNIA field are the Devonian (F2, F3 and F4), Siluro-Devonian (F6) and Cambro-Ordovician. These latest are formed by 4 sandy units alternated by layers of shale and shaly silt termed from the base to the top as follow: Unit II, Unit III-3U, Unit IV-2L and Unit IV3; these units are the subject of this study. The HNIA field is essentially gas, up to day this field is at the stage of appraisal and evaluation in order to establish a development plan; therefore the main target of this study is to contribute to this frame work. The following objectives are: ?To build a structural model of the study area. ?To integrate all the sedimentological, structural and petrophysical data in order to build a 3D geological model

Aug 1, 2013

By Zhan Zhang, Hiromi Nagaumi, Zhen Li

"Recently, the remarkable strengthening effect of ??-Al(Mn, Fe) Si dispersoids at both ambient temperature and elevated temperature were found by several researches. A large amount of dispersoids can be formed by applying special heat treatments and within a suitable range of chemical composition of AA3xxx alloys. In the present work, the influences of Cr addition on the mechanical properties and microstructures of the Al-Mn-Mg-Si alloys were investigated. The mechanical properties at ambient and elevated temperatures were evaluated by micro-hardness and yield strength. Moreover, the microstructures in as-cast and heat-treated conditions were quantitatively analyzed by optical and electron microscopes. Results revealed that Cr also had effect on the number density and volume fraction of dispersoids. Micro-hardness and yield strength at ambient temperature increased with the increasing content of Cr, and the Cr addition increased the yield strength at elevated temperature as well. Moreover, the creep resistance at 300°C improved dramatically with the increasing content of Cr.INTRODUCTION Traditionally, AA3xxx aluminum alloys were widely used in packaging, automobile and architecture industries, because of its good formability, excellent corrosion resistance and weldability. And AA3xxx alloys were considered as non-heat-treatable alloys. However, the strengthening effect of dispersoids in AA3xxx alloys was discovered recently (Li & Arnberg, 2003;Li, Muggerud, Olsen, & Furu, 2012; Li, Zhang, & Chen, 2016; Liu & Chen, 2015).Alarge amount of dispersoids could precipitate by a proper heat treatment.In order to further improve AA3xxxalloys, the composition of the alloys should be optimized. A few previous studies were reported to investigate the influence of compositions on AA3xxx alloys. Adding Mn element could enhance the precipitation of ??-Al(Mn, Fe)Si dispersoids and improve the yield strength(Muggerud, Mørtsell, Li, & Holmestad, 2013), as long as the concentration of Mn was under the solid solution limit. Fe decreased the solubility of Mn and accelerated the precipitation rate of ??-Al(Mn, Fe)Sidispersoids(Li & Arnberg, 2003), the yield strength and creep resistance at elevated temperature could increase with an optimized content of Fe(Liu & Chen, 2016). Mg element would affect the nucleation process of ??-Al(Mn, Fe)Sidispersoids by forming metastable Mg2Si(Hirasawa, 1975; Li, Zhang, & Chen, 2017a; Lodgaard & Ryum, 2000), metastable Mg2Si precipitated during heating process and promoted the precipitation of ??-Al(Mn, Fe)Sidispersoids, moreover, Mg provided solid solution strength for AA3004 alloys(Li et al., 2016). Si increased the volume fractionof ??-Al(Mn, Fe)Sidispersoids(Muggerud et al., 2013)and decreased the size of ??-Al(Mn, Fe)Sidispersoids(Li, Zhang, & Chen, 2017b). With the addition of Mo, the size of dispersoids became finer with a higher volume fraction, the volume percentage of dispersoid free zones was reduced. Elevated temperature yield strength and creep resistance improved due to Mo addition (Liu, Ma, & Chen, 2017).However, the effect of Crelements on microstructure and mechanical properties of AA3xxx alloys were rarely reported."

Jan 1, 2018

By N. R. Thornton

This paper discusses the rapid growth in the application of instrumentation for metallurgical process control. It covers such methods as ultrasonics, pulp density measurements, on-stream X-ray analysis and reagent control, as well as the expanding use of computer control and data acquisition.

Jan 1, 1971

By A. Vien, A. J. Neale, B. C. Flintoff, R. P. Edwards

Froth flotation is one of the most widely used and effective processes for mineral beneficiation. First introduced in 1911, flotation technology has seen many developments over the past 80+ years. Innovations in reagent chemistry, equipment design, process analysis and process control have given design and plant engineers a powerful set of "tools" for process optimization. However, it does not follow that all flotation systems are optimized. As Klimpel observes: "The problem with the industrial flotation process is that it is relatively easy to get reasonable results, and relatively difficult to get excellent results" Klimpel (I 988). While reasonable was sufficient in the past, competitive forces will make excellent necessary in the future. Judging by the activities in many Canadian plants this transition is already underway. This paper examines the role of some of the optimization "tools" in effecting this change.

Jan 1, 1994

By M. M. Papic, G. M. Kimber

"Hat Creek coal was treated by the liquid solvent extraction process in a continuous plant at the U.K. National Coal Board Coal Research Establishment.Extraction levels of over 80 per cent dry-mineral-matter-free (dmmf) coal were achieved.Total light oil yield was around 47 per cent of the dmmf coal. The light oil was shown to be a good feedstock for secondary refining into gasoline, jet fuel and diesel fuel.In spite of the high mineral matter content of the coal the solid residue was successfully removed from the coal extract by filtration.IntroductionBritish Columbia Hydro (BCH) and the National Coal Board of Great Britain (NCB) undertook a joint project to test the Hat Creek coal from British Columbia in the NCB's coal liquefaction process designed to produce transport fuels and feedstocks for the chemical industry by the liquid solvent extraction of coal(1), In this process most of the coal is dissolved in an aromatic solvent and the residual solids consisting of mineral matter and undissolved coal are removed by filtration. The resultant coal extract solution is fed to a hydrocracker for conversion to light liquid products and a fraction suitable for recycling as solvent. The light liquid products can be converted to gasoline and diesel fuel in a secondary refining stage.The dissolution of the coal is effected by heat-treating a slurry at a temperature in the region of 400°C which causes some bonds in the coal to rupture with the formation of radicals(2,3). These radicals are stabilized by hydrogen transfer from the hydroaromatic groups in the solvent, resulting in a reduction in the molecular weight of the coal. In the absence of donor groups the radicals combine to form an insoluble high molecular weight product(4). From studies of the kinetics of these reactions it has been shown that the formation and stabilization of the radicals is rapid at temperatures around 400°C(2,3). The dissolution of the depolymerizing coal is, however, relatively slow and the need to ensure complete dissolution in order to achieve a high extraction restricts the selection of digestion time(5). Further, it is important that digests do not contain depolymerizing coal as it may re-form under the applied stress in the filter cake inhibiting flow through the bed and resulting in low filtration rates(6).Thus, in practice relatively long digestion times are generally required in order to ensure complete dissolution of the depolymerizing coal, while it is also important to avoid depletion of the hydrogen donor groups in the solvent which would lower the rate of hydrogen donation to the coal and thus reduce the extraction yield and adversely affect the filtration(7). Clearly it is desirable to optimize the digestion time and temperature with regard to the extraction yield and filtration properties.The precise control of the distribution of products from the hydro-cracker is important for the composition of the recycle process solvent. The principal functions of the solvent are to provide a source of donatable hydrogen and a vehicle for the dissolution of the depolymerizing coal. Hydrogen transfer from the solvent, achieved by the conversion of hydroaromatic to aromatic groups, stabilizes the radicals formed by thermal cleavage of some of the bonds in the coal resulting in a progressive reduction in the size of the coal molecules(8,9) and dissolution in the solvent. The combination of radicals would result in the formation of insoluble material and a reduced extraction yield of the coal(4). Thus to achieve a high extraction yield the solvent should contain sufficient hydrogen donor groups to prevent extensive radical combination. The composition of the solvent should also be controlled to allow dissolution of the depolymerizing coal and to prevent precipitation of this material during the subsequent processing of the coal digest and extract solution. The formation of a precipitate not only reduces the extraction yield of the coal and adve"

Jan 1, 1985

By J. G. Pearson, F. H. MacDougall, A. G. Galley

The difference in age, host rock lithology, alteration and style of mineralization indicates a fundamental difference in the format ion of gold deposits in the Flin Flon and Amisk Lake areas. The Flin Flon area contains early quartz-sulfide-gold veins fo rmed within intermittently active fractures and later plutonic hosted deposits thought to be generated in a porphyry system. In the Amisk Lake area two types of gold occurrences are recognized: I) gold-quartzcarbonate- sulfide veins within or flanking fault zones and 2) structurally and stratigraphical ly controlled zones of dissem inated and vein type sulfide-gold mineralization within extrusive and intrusive rhyolite and dacite porphyries. Both types of deposits are set within supracrustal rocks. are accompanied by intense alteration haloes and were formed prior to the major deformation event suggesting an early, epigenetic hydrothermal origin.

Jan 1, 1986

By Z. Y. Liu

A local additional potential model (LAPM) was developed to illustrate the role of strain rate in stress corrosion cracking (SCC) of pipelines. According to LAPM, both density and mobility of the local active spots on the steel surface, i.e., dislocation emergence points, increase linearly with strain rate. Generation of such active spots introduces an additional negative potential locally, affecting the electrochemical reaction and, consequently, the susceptibility of the steel to SCC. Electrochemical corrosion measurements, slow strain rate tests and electrochemical hydrogen permeation test were combined to demonstrate the validity of LAPM to illustrate pipeline SCC in an acidic soil solution. It is found that a maximum of the SCC susceptibility occurs at strain rate of 10-6 s1, which is associated with an enhanced hydrogen evolution due to the local additional potential (LAP) effect.

Jan 1, 2010

By J. D. Corbett

The spatial coincidence of the seven anomalies is obvious, even though the self-potential is offset northward. Because the ratio, as an indicator of conductivity, is a relative estimate at best, concise interpretation is limited in almost every instance to the location of a conductor or conductor axis. When related to the initial phase of an exploration program, magnitudes and ratios similar to those obtained from any one of the methods described, would be sufficiently attractive to warrant further investigation. The compilation shown is an empirical comparison of actual field results and no emphasis has intentionally been placed on the relative merits of one method in respect to another. Too many additional factors, i.e., size, depth and conductivity of overburden, etc., that cannot unequivocally be answered, enter into such a comparison before a relative evaluation can be made.

Jan 1, 1961

By Nur Hossain

Analysis of Linear Elastic Fracture Mechanics (LEFM) parameters via the Virtual Crack Closure Technique (VCCT) has been obtained for SENT specimens of AM6OB magnesium alloy. It is found that the ratio of initial crack length to initial monotonic plastic zone size is one of the critical factors in establishing the limit of using LEFM concepts. If this ratio is below a certain limit (i.e. when crack lengths are small in comparison to the plastic zone size), loss of similitude stress intensity factor range would occur. This ratio, therefore describes the limit below which the use of LEFM would no longer be admissible. In this study, the above limit was established for AM6OB magnesium alloy. In addition, fatigue crack propagation tests were conducted to ascertain the fatigue response of the alloy and determination of the coefficients of Paris model.

Jan 1, 2010

By Roger J. Berdusco

Kaiser Resources Ltd. owns and operates a 5-million-tonper- year open-pit and hydraulic coal mine near Sparwood in southeastern British Columbia. Since 1969, Kaiser has maintained a field-scale reclamation program dedicated to the reclamation of disturbances associated with past and present mining and exploration activities . Since that time, over 1400 acres have been treated using modified forestry and agricultural techniques with encouraging results.

Jan 1, 1978

By J. D. Bateman

DURING the summer of 1942 several chromite deposits were discovered in the Lac du Bonnet district about eighty miles northeast of Winnipeg. The deposits are confined to the Bird River complex, a folded composite sill of basic and ultrabasic igneous rocks of early Precambrian age that lies to the north of Bird river (1). The outcrop of the sill represents the trace of an easterly plunging anticline, the south limb extending from the northeast bay of Lac du Bonnet eastward to Bird lake, and the other limb, 6 to 12 miles north, lying between Maskwa river and Euclid lake. The south limb of the sill is 20 miles long, and the northern counterpart 15 miles; but its continuity is interrupted by faulting and by the intrusion of younger granite, so that the total length of outcrop of both limbs does not likely exceed 25 miles. The sill is intrusive into early Precambrian greenstones and associated sedimentary rocks. The chromite discoveries have been made at several localities on both limbs of the sill, and in each case at the same geological horizon. The sill comprises an upper layer of hornblende gabbro and a lower layer of serpentinized peridotite, and altogether is from 500 to 3,500 feet thick. The chromite zone is within and near the top of the peridotite layer, and thus about midway of the sill, both of the limbs of which stand nearly vertical. This geological relationship was established early in the exploration of the initial discoveries and served as the basis for successful predictions of later discoveries. The chromite zone probably persists throughout the length of the sill, but its width and chromite content are not everywhere the same. The initial exploration along both limbs of the sill has shown a combined total length of about 12,000 feet of chromite ore varying in width from 6 to 12 feet. In many places the overburden is thick and obscures the continuity of the chromite zone; but as investigation proceeds the known deposits will be extended and new ones will be found. Thus, although a total length of 12,000 feet of ore has been investigated up to the present time, there is an indicated length of approximately 31,000 feet along which the ore is more than 4 to 5 feet wide. This estimate is based on geological considerations and represents a total tonnage in the order of 15,000 tons per vertical foot of depth.

Jan 1, 1943

By F. W. Wellmer

"This paper discusses the changing nature of reserve/consumption ratios, using data from Canadian operations and focussing particularly on copper.IntroductionStudies in world metal consumption and world metal reserves are done regularly by the U.S. Bureau of Mines, the German Federal Institute of Geosciences and Raw Materials, and other institutions. Formerly, on the basis of these data, the following figures were calculated:• a static lifetime of reserves-reserves at year end divided by the consumption of the previous year;• a semidynamic lifetime of reserves-reserves at year assumed constant growth rate.These figures were severely criticized because they were purely theoretical and did not consider the availability of the raw materials.Recent practice is to calculate reserve/consumption ratios (R/C ratios) for periods(1) or for different years(2,3) and to interpret the trend. For base metals, these R/C ratios are increasing (Table 1). This had led to the conclusion that today the relative availability of base metal reserves has increased as compared to 10 or 15 years ago(4,5) As there are normally numerous deposits for each commodity, the anticipated production rates of deposits are irrelevant to this conclusion as long as the statistical distribution of possible production rates does not change significantly.The above conclusion is only justified if the quality and the nature of the data base remain the same. This is certainly the case for the consumption data. It is also assumed for the quality of the reserve figures, which usually take into account only proven and probable reserves. For the nature of the reserve figures, however, this does not seem to be true.Undoubtedly, the reserves increased in absolute terms between 1966 and 1978. To put the absolute reserve figures into perspective, it is common, as said above, to compare them with the mine production, which increased in the free world between 1966 and 1978; e.g. for copper by 40%, for Pb by 17% and for zinc by 36%. However, the reserves are also influenced by other factors, such as average size of the mines, changes in the grade of the mined ore, price-to-cost relationships and the like.The purpose of this paper is to examine the nature of the reserve figures in more detail. Because the completeness of mining data published in Canada is rather exceptional, Canadian .data serve as an example and it is assumed that the conclusions can be extrapolated to other mining countries or at least to those with free market systems."

Jan 1, 1981

"In the first half of 1990, Cambior earned $1104 million, or $0.37 per share, on revenues of$66.4 million. The company's strong cash position, attained late in 1989 and in the beginning of1990 through the exercise of warrants, put working capital at $83.8 million as of June 30, 1990. Long-term debt was reduced by over $10 million during the weak gold market, leaving the company with a debt to equity ratio of only 0.03. Production for the six first months of 1990 was 107 720 oz. Au, an increaseof24% over the corresponding period in 1989.Financial Profile/Results and Corporate Financial StrategiesTotal revenue for the 1989 fiscal year was $116,883,000 compared to $109,848,000 for 1988. The 1989 results achieved despite a lower average gold price, resulted from a higher level of commercial gold production and a 115% increase in investment income over 1988. Investment income rose to $3,568,000 in 1989 due to higher levels of cash assets.Cambior's mine operating costs increased 19% to $68,561,000 in 1989 from $57,472,000 in 1988. This increase resulted from rising operating costs at the Doyon Mine ($250/oz to $274/oz) due to the shift from open pit to underground operations, as well as from the start -up of three new mines with relatively higher costs. These costs have reached a stable level that should be maintained for the next few years.In 1989, net exploration expenses were $6,838,000, down 31070 from 1988, partially due to the Canadian tax reforms introduced since 1987. Depreciation and depletion grew by $1,432,000 in 1989, reflecting a higher volume of commercial production from the Pierre Beauchemin, Lucien C. Beliveau and Chimo mines.Net earnings for 1989 amounted to $17,661,000 or $0.73 per share compared to $17,438,000 or $0.74 per share in 1988.Cambior has an exceptionally liquid and strong balance sheet. As at December 31, 1989, net working capital stood at $85.6 million, with a total assets base of $338.6 million. With a long-term debt (including gold loans) of $21.5 million and shareholders' equity of $277.2 million, Cambior has a debt to equity ratio of 8%. All but about $100,000 of long-term debt is in the form of gold loans.The total market value for Cambior's stock as at September 10, 1990, stands at $420million, based on recent stock market prices. Cambior's stock and warrants are traded on the Montreal and Toronto Stock Exchange."

Jan 1, 1990

By M. J. Medd, G. A. Speirs

"This paper describes the simultaneous sinking and equipping of a 4.9 m diameter concrete-lined shaft to a projected depth of 1660 m. The shaft blast design utilizes the full face method using a parallel hole burn cut. Hydraulic drilling and a totally redesigned Cryderman-type mucking unit were integrated into the four deck sinking stage to provide for drilling, mucking, concreting and shaft steel equipping operations. A safety program was tailored and implemented specifically for this shaft sinking project.IntroductionIn July 1988, Falconbridge Limited commenced development of its Thayer Lindsley exploration site located some four km north of Sudbury on Regional Road 80.The first phase of this project was awarded to J .S. Redpath Mining Consultants Limited and the scope of work included the engineering and project management to construct a surface plant capable of supporting a shaft sinking and exploration program for potential future mine development. This initial phase of the project was completed on schedule and under budget on December 23, 1988, and is the subject of an independent paper.In November 1988, J.S. Redpath Limited was awarded the shaft sinking and exploration phase of this project. The scope of work consisted of sinking and equipping a 4.9 m diameter shaft to a depth of 1660 m and carrying out the development and diamond drilling on two levels. This work was scheduled to be completed by November 1991.The T .L. Exploration Project is located toward the eastern end of the south range of the Sudbury basin, north of Sudbury. Figure 1 details the projected mining area and the shaft location on the geological complex. Figure 2 is a section showing the exploration shaft that is located in the Norite. Two levels will be developed from this shaft, on the 1310m and 1588 m levels, to provide access for further geological examination of the ore bodies."

Jan 1, 1991