Search Documents

By Hung-wei Liu, Kevin Plucknett

Early attempts to manufacture titanium aluminides using blended elemental powders, through powder metallurgical processes, have been obstructed due to serious swelling during sintering. Although the use of pre-alloyed powder can avoid this undesired expansion problem, there are limited commercial powder sources available. Therefore, in the present research, fundamental studies on the synthesis of dual-phase (? plus a2) Ti48Al intermetallic materials is undertaken, in particular assessing powder manufacture. In order to produce pre-alloyed powders, highly porous Ti48Al pieces are initially sintered from elemental Ti and Al powder blends, and subsequently pulverised into powders. The powder size is then further reduced by use of either dry or wet milling processes (i.e. shatterbox grinding, attrition, or ball milling). Among these methods, shatterbox grinding has shown the highest efficiency, with a slight mechanical alloying effect observed. The manufactured powder morphologies and phases, as well the sintered material, will be discussed.

Jan 1, 2015

By M. B. Myers

The subject matter of this paper will be discussed under three main headings. 1.-Fire-Resistant Fluids: (a) the need for such materials, based on historical events; (b) a definition of fire -resistant fluids; (c) general description, characteristics, operational parameters, advantages and disadvantages of oil-in-water emulsions (HFB), water-polymer fluids (HFC) and anhydrous or synthetic fluids (HFD). 2.-A review of equipment associated with the use of fire-resistant hydraulic fluids; (a) performance testing of hydraulic equipment, i.e. gear pumps, vane pumps, axial and radial piston pumps, hydraulic motors, etc., pressure, speed, filtration limitations, etc., and effects on valves, elastomers, paints, etc.; (b) hydraulic system design features and selection of suitable units; (c) types of mining applications currently employing fire-resistant fluids. 3.-Test methods used to evaluate fire-resistant fluids: (a) fire testing methods, i.e. wick tests, spray ignition testing, hot manifold tests, factory mutual tests, all to establish fire-resistancy parameters and acceptance; (b) new developments in fire-resistancy evaluation; (c) the examination of other performance tests, e.g., effects of evaporation, sliding wear, life of rolling element bearings, etc.

Jan 1, 1979

By Yve Potvin, Fabien Miller, Deni Jacob

"The potential benefits of measuring the volume of excavated open stope are enormous. By comparing the actual excavation of the orebody contour, it is possible to determine the “real"" amount of mining dilution, as well as the ore left in place. Noranda Technology Centre (NTC) has developed a stope survey system that allows for rapid and efficency measurement of underground excavation volumes. The system comprises a commercial laser (EDM), a set of lightweight rigid rods, an automated scanning device, a hand-held data logger and Autocad-based software for volume calculation and drawing manipulations. This system is an invaluable tool for the optimization of mining practices and could also be used for the delineation of caving areas. IntroductionDilution is the most common and devastating mine disease. In some instance s it could systematically cripple the profitability of an operation, and in more extreme cases, it could become a terminal disease. The Northern Miner Journal (1988) reported that many operations have closed because of uncontrolled dilution, before they even completed their first year of production. Other studies (Pakalnis, 1986) have shown that approximately 40% of all underground operations have more than 20% dilution. Considering that every ton of dilution costs in the neighbourhood of $25, the total direct cost of dilution to the Canadian mining industry may easily exceed one hundred million dollars per year.The dilution problem has been a major concern to Noranda Minerals for some time and in 1984 a comprehensive geomechanics research program was created at the Noranda Technology Centre (NTC) in Pointe-Claire, Quebec. New empirical stope dimensioning techniques, improved cable bolting techniques and sophisticated ground control instrumentation projects (among others) contributed to improve the situation at Noranda.A new tool which can have a very significant impact on the ""war"" against dilution is being developed by the Noranda Technology Centre. The laser stope survey system allows for a rapid, precise and efficient measurement of underground excavation volumes. By comparing the excavation planned with the volume excavated, it becomes possible to determine the ""real"" amount of mining dilution as well as the amount of ore left in place. This system may also allow for early detection of a dilution problem. As with other diseases, early detection provides the best chance for a fast and total recovery."

Jan 1, 1992

By W. G. Q. Johnston, J. S. Fox

"A semi-continuous belt of Aphebian magnesian extrusive and related sub volcanic rocks has been delineated by the authors over a distance of 150 kilometres in the central La Ronge lithostructural domain in Saskatchewan. They range in composition from peridotite to basalt and attain true thicknesses of up to 800 metres. For the most part, they are confined to a basal position in the La Ronge/Wasekwan metavolcanic sequence, and appear to have been extruded onto sialic crust. However, at Lynn Lake, Manitoba, in the eastern continuation of the domain, similar rocks seem to be found only at a relatively high stratigraphic level.Although metamorphism seems to have obliterated any quench textures that may have existed in these rocks, ultramafic pyroclastics, pillows and amygdules as well as intercalated, fine-grained clastic sediment attest to the volcanic nature of these rocks. Bulk chemical analyses indicate that these rocks are heterogeneous, with komatiites, tholeiitic picrites and even rocks with some of the characteristics of boninite all being present. The close temporal and spatial relationship of ""boninites"" and komatiites in the belt may suggest a high degree of Aphebian mantle inhomogeneity in the domain.Nickel-copper mineralization has been found in differentiated tholeiitic stocks within the La Range domain (e.g., at Lynn Lake), but none has yet been found in the ultramafic volcanics. However, the tholeiitic picrites do host one economic gold deposit - the Agassiz Mine at Lynn Lake .Because of the depleted nature of their mantle source, the ""boninites"" of the domain are not considered to be likely hosts for mantle-derived nickel sulphide mineralization. However, the opposite is true of the komatiites, and this points to the need for whole-rock geochemistry in setting priorities for nickel exploration in the belt. In contrast, all of the magnesian rocks of the domain probably have the same gold potential. Inasmuch as the geophysical response to gold mineralization in the domain is likely to be unpredictable, lake-sediment geochemistry, followed by base-of-till and/or alteration oriented lithogeochemistry, should be emphasized during gold exploration."

Jan 1, 1981

By Christopher Andreae

"Years before the present iron and steel works were established at Sydney, several thriving although short-lived iron work s operated in Nova Scotia. These furnaces reflected the general nineteenth-century North American experience with iron work s. At the beginning of the century, small furnaces struggled to supply local needs. Charcoal was the principle fuel and water powered most furnace equipment. By the end of the century, a few huge primary iron and steel work s dominated production for Nova Scotia and the rest of Canada.Two sites achieved prominence in the nineteenth-century Nova Scotia iron industry: Londonderry and Ferrona. Londonderry, the larger and longer-lasting of the two sites, is today a small village on the south flank of the Cobequid Mountains, about 30 km west of Truro. Prior to the establishment of an iron works in 1849, no community existed. At the peak of operation in the 1880s, however, over 2,600 people were located there. The second site, Ferrona, today is a mere crossroads on the map, about 10 km south of New Glasgow. Following the construction of a blast furnace there in 1892, a small village grew up around the furnace, but once the furnace was blown out in 1904, the population gradually drifted away.Early HistoryThe history of Nova Scotia's iron industry began in 1604 when Samuel Champlain became the first European to identify iron ore in the future province. Despite this early acknowledgment, iron was not smelted commercially in Nova Scotia for another two hundred years. Although primitive smelters of the period produced more iron than could be used locally, early settlers depended on imports of iron from Britain and the United States."

Jan 1, 1983

By J. C. O'Rourke

"Gibraltar Mines Ltd. has been operating its open pit copper mine for fifteen years. In that time, over 140 million tons of waste and low-grade material has been placed on the mine waste dumps. Laboratory and in situ testing indicated that enough leachable copper was recoverable from the dumps to justify a leaching operation which would include the construction of a solvent extraction-electro winning plant. The plant, which was commissioned in October 1986, was designed to process 3000 USGPM of dilute copper solution to produce 5000 tons per year of high-quality cathode copper.This paper deals with the start-up and initial year of operation of this plant. The three areas: leaching, solvent extraction, and electrowinning are presented with emphasis on the innovations which were made to help overcome the problems unique to the Gibraltar operation.The Leaching CircuitThe mine waste dumps are leached to produce a pregnant copper solution as feed to the SX-EW plant. To achieve this the dumps are sprinkled with a mildly acidic solution which percolates through the dumps. In travelling through the dumps the solution contacts the surfaces of the liberated copper minerals and dissolves the soluble copper into the form of copper sulphate. The leaching reaction is achieved by a combination of bacterial action to oxidize the sulphides and solubilization of the copper into the acid solution.For the bacterial action to occur the dumps must be near the ideal pH of 1.9 to 2.1 and the necessary elements of the reaction must be present. Because a bacterial reaction is involved there is a lag time between the time when the conditions for bacterial growth are achieved and when the bacteria are in their active growth phase. Laboratory leaching tests with Gibraltar ore indicated that bacterial action takes two to three months to reach its maximum rate (Fig. I).The expected lag time for the planned rate of bacterial leaching prompted Gibraltar to start irrigating the dumps in late June 1986 for a plant start in early fall. The lag time proved to be longer than expected and the dumps took until November to start producing copper at the expected rate (Fig. 2)."

Jan 1, 1988

By David E. Pearson

"Western Canadian coking coals are located in the Rocky Mountains arid foothills of British Columbia and Alberta. They are typical of non-marine coals, characterized by total sulphur contents of less than one per cent and with ash contents of 10-30 weight per cent. This mineral matter is composed principally of kaolinite and quartz.The petrographic compositions of most of the coking coals which constitute the 2.065 billion tonnes of British Columbia's measured reserves, and the compositions of the metallurgical coal currently exported from Alberta, show them to be rich in the inertinite macerals, macrinite, fusinite and semifusinite. When the mean maximum reflectance of vitrinite in oil/Romax) is used as the coal rank parameter, this high inertinite content is reflected in the lower volatile-matter yields, but the relatively inert character is also displayed by lower free swelling indices (PSI), lower maximum dilatations, lower maximum fluidities and lower coke strengths than other coals of the same rank, but richer in the reactive macerals, vitrinite, exinite and semifusinite. Despite these reduced values in the so-called caking tests, inertinite-rich coals produce strong coke.A system of classification of coking coals is introduced which is based on rank, as indicated by Ro max, and either petrographic composition, maximum dilatation, maximum fluidity or, to a lesser extent, PSI and volatile-matter yield. Six principal coal groups can be distinguished among coking coals using this versatile classification. Inertinite-rich coals are assigned to the Keystone Group (GI), Balmer Group (G3) or Moura Group (G4), each group being named for a coal typical of that population ofcoals. Reactive-rich coals are assigned to the Pittston Group (G2), Kellerman Group (G5) or Big Ben Group (G6). A multiple-regression analysis of coal quality versus price shows how the value of coking coal in the Japanese market appears to be related to reflectance and the free swelling index, and confirms the economic viability of the classification.British Columbia's measured reserves of coking coal contain representatives of four of these groups; Balmer Group (73%), Moura Group (/6%), Pittston Group (3.4%) and Kellerman Group (7.6%).This analysis of the quality of Western Canadian coking coal indicates that despite the need for large proportions of inertinite-rich coking coal in blends produced in the Japanese steel industry, there is nevertheless a demonstrated overabundance of Balmer Group and Moura Group coals available to the international coking coal market."

Jan 1, 1980

By Peter A. Bevan

"In massive and semi-massive deposits, it is essential to take samples continuously for specific gravity determination as well as for assays of the various metals of interest. Failure to use specific gravity in mixed deposits of high density contrast will result in incorrect determinations of the average grade.Graphs and linear equations of specific gravity against the grade of one metal are not considered accurate enough in a multi-mineral deposit, but appear to be very satisfactory in a theoretical one-sulphide/gangue mix. Specific gravities based on base-metal values only in massive sulphide deposits will result in underestimating the effect of low grade areas on the average grade and also cause a reduction in the calculated tonnage.IntroductionBy definition, a base-metal assay is the percentage of metal by weight contained in a sample, whether it be a soil or silt sample, a grab, chip or channel sample, or a section of diamond drill core.In those cases where there is a series of contiguous samples, say in diamond-drill core, the average grade may be required of the various assays that are above a desired or required cutoff grade.Internal low grade or waste can be included if the assays one side or the other are used to ""carry"" the lower grade material and the resulting average grade is above the cut-off grade. To determine the average grade, the individual assays are ""weighted"" by multiplying these values by their respective lengths, adding up the cumulative assay times length and dividing by the total length. This method is essentially a weighting by volume, because the core diameter is constant and is common to all the samples being considered for estimating the average grade . If some of the core samples have much higher specific gravities than others, and the specific gravities are not used in the weighting process, the resultant average grade will be over-estimated or underestimated, depending on the grade of the heavier sections. When core assays of approximately the same specific gravity or weight are averaged by length, the error in the weighted estimation of the average grade is negligible."

Jan 1, 1993

By H. Warren Newcomen, Dennis C. Martin

"This paper describes the investigation of a large, progressive slope failure on the southeast wall of the east pit at Highmont Mine, British Columbia Geotechnical investigation s consisted of geological and structural mapping, assessment of blasthole drilling records, review of rock core information, slope movement monitoring and back analysis of various possible failure modes. Climate records and mining history were also assessed to determine their relationship to slope movement.Analysis of movement monitoring records and geotechnical information indicates that the failure is deep seated. The upper portion of the failure surf ace occurs along clay filled discontinuities. The lower portion of the failure surf ace appears to occur through the highly altered rock mass. High groundwater pressures and mining at the toe of the slope are documented to have had a major influence on stability at various times during the failure. Stability analyses results are presented and possible remedial measures are discussed.IntroductionHighmont Mine is located near Logan Lake in the Highland Valley approximately 50 km southwest of Karnloops, British Columbia (Fig. I). Mining of the porphyry copper and molydenum ore bodies began in 1980. In May, 1983, when mining in the east pit had progressed to a depth of about 60 m (200 feet) , a failure (designated the Southeast Failure) began to develop in the southeast corner of the east pit. Subsequent mining to a depth of 110m (360 feet) was accompanied by frequent and substantial slope movements involving between 500000 and I 000 000 m3 of rock . The slope was monitored extensively to assess short-term movement trends for operational safety. Geological mapping, core logging and rock mechanics testing were used in conjunction with the long-term monitoring information to determine the failure mechanism, conduct stability analyses, assess the effects of instability on pit design and enable design and installation of remedial measures."

Jan 1, 1988

By L. Chunpongtong

ABSTRACT The mining limit in oil sands is regulated by the ratio of total mining volume (ore, interburden, and overburden) one has to mine per volume of bitumen in place (TV/BIP). This paper presents a mathematical solution for creating the most economical pit outline where the TV/BIP ratio upper limit is 12, by combining mining economic theory and the Lerchs-Grossmann (LG) algorithm.

Jan 1, 2014

By L. W. Krahenbil

The programmable Logic Controller (PLC), at its present stage of evolution, is now considered as a mature control system. The PLC combines the solid-state reliability of hardwired logic and computer control systems with the simplicity of a relay ladder logic. Relay symbolic programming through a function-oriented keyboard provides a means which plant personnel can easily become accustomed to work with. In a large coal facility, it is shown that the control engineer can provide improved control flexibility with the advanced capabilities of the PLC.

Jan 1, 1979

By Euler De Souza

"The uninterrupted operation of a ventilation system is critical to ensure the mine meets its scheduled production and, as important, is vital to the health and safety of all personnel working underground. Those operating the mine ventilation system must have fundamental engineering training in the art of fluid dynamics and have a good comprehension and control of the mine ventilation network. Ventilation management by untrained and inexperienced personnel may result in serious consequences when the system becomes ineffective. This paper shares observations and experiences pertinent to the occurrence of upset conditions as a result of the improper design and operation of mine ventilation systems. A series of real life case studies are presented to describe disruptions to mine ventilation systems and the gradual deterioration of system operational efficiencies leading to eventual failure. Special focus is given to mistakes made and on the resulting serious consequences. The case studies also demonstrate how each upset condition was resolved, permitting the mines to safely resume production activities.INTRODUCTIONThe ventilation of operating mines is a continuously changing and evolving system; upset conditions will occasionally occur, but should be promptly resolved in order for the system to function properly, according to design, and in compliance.Those designing, managing or operating the mine ventilation system must have pertinent training and have a good understanding of fundamental ventilation concepts to be able to devise and implement engineering solutions to day-to-day challenges. Realistically, the operator must also have extensive practical experience and be able to effectively apply operating procedures, design criteria and ‘best practices’. They must be able to, on a daily basis, evaluate the mine ventilation system, determine and locate any problems, understand the causes of each problem, find a solution, and promptly and efficiently correct those problems.Ten case studies are presented to demonstrate how fundamental design or operational mistakes can lead to adverse conditions or to catastrophic consequences, how detailed on-site engineering assessments can be employed and how simple, low cost, engineering solutions can be implemented to successfully resolve the issues and return the ventilation system to compliance, permitting the mines to safely resume production activities."

Jan 1, 2019

By Arnold R. Pasieka, George V. Sotirow

"The object of this paper is to outline a computerized net cash flow approach for practical cutoff grade determinations. A cutoff grade carries not only geological but also economic value, in which costs are balanced against revenues. For different situations, cutoff grades are a 'standard of value' that are determined for the purpose of classifying economic or uneconomic mineral reserves in a specified time frame. In a constantly changing technical and economic environment, the decision to develop or maintain a mining operation at its best economic potential, requires an appropriate cutoff grade strategy, a strategy consistent with short- and long-term operational and corporate objectives and one based on realistic marketing and metal prices forecasts. The use of a project evaluation computer program, in combination with specific corporate net cash flow requirements, shows the most promising and flexible team approach for cutoff grade optimization.IntroductionThe recent recession has had a devastating effect on the Canadian mining industry. Exploration and mining R&D expenditures have been critically reduced and now are believed to be below healthy levels. Ore reserves, mine life and cutoff grades are careening in several directions because of low base metal prices, relatively high costs and sensitive precious metal prices.These conditions demand an improved understanding of the terms ""ore"" and ""cutoff grades"" as they are applied to the planning process and day-to-day operations. ""Ore"" or 'ore reserves"" is a dynamic concept, reflecting a cumulative effect of changes in geological, technical and economic conditions in terms of material which can be mined at a potential profit. By contrast, if economics are not the primary consideration, the term ""mineral reserve"" or ""mineral inventory"" should be used to describe the mineral deposit. For different situations, cutoff grade is ""a standard of value"" determined for the purpose of classifying mineral reserves as economic or uneconomic in a specified time frame. The question of mining at average reserve grade or low-grade material during high metal prices is of paramount importance for cutoff grade strategy."

Jan 1, 1985

By J. Donovan

Underhand cut and fill mining is being planned for selected areas at the David Bell Mine where high ground stresses have resulted in particularly challenging mining conditions. In order to test the placement and performance of a variety of underhand cut and fill paste mats three different designs have been installed and extensively instrumented along the A-Zone 9C ore sill. The sill is approximately 87m long, 4.0m high, and 5.0m average width. The sill was broken into 3 sections each of which will contain one of the sill mat designs. The underhand sill will be mined 3.75mW x 4.0mH, allowing for some overbreak while minimizing the risk of the back span exceeding the design limit of 4.0mW. Each test sill mat includes pre and post-support and includes 0.5m (18?) broken muck mat placed along the sill floor. Upon developing beneath these mats quantitative and qualitative measures will be used to determine which design is the most suitable for application in underhand mining at David Bell.

May 1, 2007

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 Ralph Harris, Javier Jara

"Oxygen is essential in gold cyanidation. It is supplied to the leaching media by sparging oxygen or compressed air into the cyanidation tank. The rate of oxygen transfer is critical to achieve the desired oxygen concentration in solution.The performance of a novel device for gas sparging recently developed at McGill University is compared to the mass transfer characteristics of the two spargers most used in the gold industry: the four lance configuration and the inverted cone. The distribution of gas and the kinetics of oxygen desorption of the three types of spargers was studied in a 140 litre tank. The oxygen dissolution of the new device is three to five times faster than the other spargers. This could increase the leaching rate and/or decrease the cyanide and oxygen consumption.IntroductionIn hydrometallurgical processing, it is often necessary to bubble gas through a pulp to carry out the wanted reactions. The gas can act to agitate the pulp and it can also supply reactant. The rates of the reactions which require a reactant supplied by the gas are often dependent on the rates of mass transfer from the gas to the solution.A common example of this is gold cyanidation which requires oxygen for gold dissolution. Since the gold containing slurry is rich in other oxygen consuming substances (sulphide like pyrrhotite), it is important to provide enough oxygen to allow complete gold dissolution within the residence time of the cyanidation reactors. It has been demonstrated that the rate of gold dissolution is directly proportional to the dissolved oxygen concentration of the pulp which in turn is proportional to the oxygen partial pressure in the bubble 1 2 3. Improving the rate of mass transfer of oxygen increases the dissolved oxygen concentration of the slurry and therefore improves the rate of the reaction.The rate of mass transfer from a bubble to its surrounding solution increases with decreasing bubble size and increasing gas bubble residence time which in turn increases with decreasing bubble size. The generation and dispersion of small bubbles is thus critical to achieving high rates of mass transfer. Different configurations and devices used to inject gas have different effects on the bubble size and the residence time, influencing the overall rate of mass transfer. Therefore better mass transfer can be achieved by adopting a more efficient method.The methods tested in this report are the four lance configuration (wall spargers), the inverted cone and a new device, designated HCD. The wall spargers and the inverted cone are used widely in the industry today."

Jan 1, 1994

By A. Himsley, E. Byleveld

"With reference to the chemical constraints underlying the ion exchange process for uranium recovery, a generalized view is presented on the actual and the achievable efficiency of the process. The area considered is restricted to acid leach circuits in combination with nitrate, chloride or sulphuric acid elution.A comparison between actual plant results and the chemical requirements shows that:(a) Unless new and better ion exchange resins are developed, no dramatic change in equipment size and resin inventory is""anticipated. (b) Elution efficiency, especially for sulphuric acid, may be improved considerably. More concentrated eluates may beproduced at lower chemical consumption. A possibility of achieving additional purification solely by ion exchange is discussed.IntroductionThis paper presents a generalized view of the actual and the achievable efficiency of the ion exchange processes for urannium recovery. The study is restricted to acid leach circuits in combination with nitrate, chloride or sulphuric acid elution. The ultimate efficiency attainable with ion exchange is dietacted by the chemical reactions underlying the process. The most sophisticated technology cannot change the diffusion rates in the ion exchange resin nor make the uranium loading exceed its equilibrium valueThe design of an ion exchange plant for uranium recovery involves a considerable number of parameters as a result of the wide variety of pregnant solutions produced from different orebodies. Therefore, a generalized approach of the ion exchange process inevitably neglects some parameters which maylead to significant variations in apparently identical situations.The uranium concentration in the pregnant solution, together with its pH, are the principal variables which determine resin loading and residence rime in the ion exchange system. On the elution side, the type of eluant and its concentration will determine the contact time required and the amount of eluant needed to strip the resin. The temperature, the properties of the ion exchange resin, the total dissolved solids in the feed solution and the competing ions are other variables that affect the chemical performance; these, however, may be considered as a correction of the principal parameters if one is interested only in general trends."

Jan 1, 1980

By Ed McConaghy, P. LaRochelle

The Ambatovy Nickel Project comprises the development of mine, hydrometallurgical processing facilities and necessary infrastructure in Madagascar, positioning Ambatovy as one of the world’s largest producers of nickel and cobalt from lateritic ore. SNC-Lavalin successfully provided comprehensive Engineering, Procurement, Construction Management (EPCM) services for this major capital project which, apart from its sheer size, scope, and engineering design, represented significant location, infrastructure, labour, environmental and climatic challenges. Today, the project has reached 90% of its nameplate capacity and is in its final performance optimization stage. This paper will discuss the significant project management effort that was required to successfully address the complexity of this major project. It will cover the main project management control systems and the engineering tools and processes used during the detail engineering, procurement, and construction phases to achieve optimum project execution.

Jan 1, 2015

By S. Jeon, T. H. Kim

"Understanding the frictional properties of discontinuities is crucial to ensure the stability of underground structures. In particular, the frictional behavior at depth depends on the complex interaction among mechanical, hydrological, thermal and chemical characteristics and their coupled effects. In this study, a series of triaxial compression tests were carried out to investigate the behavior of rough shear surface of synthetic rocks. The frictional behavior showed little variation at different confining and water pressures. The test results were analyzed using Coulomb’s failure criterion. In addition, numerical analysis was carried out using PFC2D to simulate the test.INTRODUCTIONUnderstanding coupled behavior of rock at depth is of great importance in design, construction and operation of underground structures such as a disposal facility of radioactive waste, hot dry rock geothermal system and oil reservoir. In particular, many uncertainties are involved in characterizing deep rock mass deformation in the designing process and interactions among fluid flow of groundwater, high temperature and stress disturbance should be considered. Many independent studies have been carried out to investigate the thermal, hydro, mechanical and chemical coupled effects in numerical and experimental methods. They include the researches by Lockner, Summers, Moore and Byerlee (1982), Jafari, Amini Hosseini, Pellet, Boulon and Buzzi (2003), Tembe, Lockner and Wong (2010), Lee, Lee and Jeon (2012), Indraratna, Premadasa, Brown, Gens and Heitor (2014)."

Jan 1, 2015

By WENDY MARTIN

The Eastern Townships and Asbestos Hill areas are the current asbestos-producing districts of Quebec. Mining in the two areas began in the /are 1870s and 1972 respectively. Production from the Eastern Townships is derived from rhe Serpentine Zone of ulrramafic rocks, specifically from basal serpentinized peridotite members of what are now considered to be allochrhonous ophiolitic material that was abducted onto the Early Ordovician continental margin. From south west to northeast, the rhree allochthonous asbestos-producing sections of the Serpentine Zone are designated the Asbestos Ophiolite Complex, the Thetford Mines Ophiolite Complex and the Pennington Dyke; the Pennington Dyke is considered to represent a segment of serpentinized Alpine peridotire that was fragmenred from a larger, more complete ophiolire complex. The Asbesros Hill deposir on the Ungava Peninsula lies in what apparenrly is an inrrusive sill found wirhin rhe Chukorar Group, the uppermosr group of Precambrian-aged Cape SmithWakeham Bay Belr of volcanic-sedimentary rocks.

Jan 1, 1984