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By M. H. Leite, R. Corthésy, D. E. Gill

"La connaissance des contraintes naturelles qui prévalent dans les massifs rocheux est un prérequis indispensable pour la conception sécuritaire et économique des excavations comme on en retrouve dans les exploitations minières souterraines. Certains chercheurs se sont attardés à colliger les résultats de mesures de ces contraintes et les ont utilisés pour produire des modèles de prédiction basés sur leur traitement statistique. Ces modèles de prédiction sont très populaires auprès des exploitants miniers puisqu’ils permettent, du moins dans les étapes préliminaires de design, d’obtenir de façon s’apéconomique mais approximative, une partie des paramètres dont ils ont besoin. Dans le cadre d’un projet initié en 1994 avec la collaboration de l’IRSST, il a été décidé de produire un modèle de prédiction englobant une partie de la zone périphérique de la faille de Cadillac, soit une zone plus restreinte que le Bouclier Canadien utilisé jusqu’ici comme région pour l’élaboration de tels modèles. Pour produire ce modèle de nouvelles données obtenues avec une technique permettant d’exercer un excellent contrôle de qualité ont été ajoutées à celles déjà disponibles. Une telle régionalisation des données de base permet d’obtenir un modèle où les intensités et les orientations des contraintes principales sont beaucoup moins dispersées que ce que rapportent les modèles publiés jusqu’à ce jour. Enfin, il est démontré que le modèle proposé pour la région étudiée est en toute probabilité plus sécuritaire que les modèles plus généraux publiés à ce jour. Knowledge of the in situ state of stress existing in a rock mass is essential to the safe and economical design of underground mining excavations. Prediction models have been published, based on the statistical treatment of stress measurement results. Such prediction models are very popular among mine operators because they allow them, at least at a preliminary design stage, to economically obtain part of the information needed, even if this information is approximative. In 1994, a research project financed by IRSST was initiated aiming to produce a prediction model that would comprise a peripheral zone around the Cadillac fault. This region is more confined than the Canadian Shield on which the existing prediction models have been based up to now. In order to produce such a model, existing stress measurement results have been used in conjunction with new stress measurements that have been performed based on a technique which allows full control of the quality of the measurements. Restricting the data upon which the model is based to a more specific region gives a model in which the intensities and the orientations of principal stresses are far less scattered than the results published to date. Finally, it is shown that the proposed model is probably safer for the studied region than the models previously published."

Jan 1, 1998

By François Robert

"The Eastern Abitibi Sub province (Quebec segment), contains two main types of gold deposits: the common quartz-vein type and the rare pyritic type. Both occur in areas dominated by volcanic rocks and are spatially associated with major fault zones.Quartz-vein gold deposits consist of simple to complex networks of quartz-carbonate-pyrite veins in reverse shear zones and extensional fractures. They occur in areas dominated by mafic volcanic rocks and are commonly associated with small syn- to late-tectonic porphyritic felsic intrusions. Associated alteration, which postdates peak metamorphism, is dominated by carbonatization, sericitization and pyritization of the wallrocks. These deposits formed late in the geologicalevolution of the Abitibi.Pyritic gold deposits range from deformed massive sulphide lenses to zones of syntectonic pyrite-rich veinlets and associated pyrite disseminations. These deposits occur in environments dominated by felsic volcanic rocks that are typically converted to sericite schists near the deposits. The associated pre-metamorphic aluminous alteration is now characterized by metamorphic sericite, andalusite, kyanite and chloritoid, overprinted by a late retrogression of alumino- silicates. These deposits probably represent deformed volcanogenic massive sulphide deposits, but the timing of gold introduction in these is not fully understood.The differences in geological attributes reflect significant differences in the genesis these deposits: the pyritic deposits probably have a multistage genesis, including a pre-tectonic stage, in contrast to a single stage late-tectonic genesis for the quartz-vein deposits.RESUMELa partie Est de la Sous-Province de l’Abitibi( segment québécois) renferme deux types de gites d' or: ceux de type ""veine de quartz"" et ceux, plus rares, de type ""pyriteux"". Ces deux types se trouvent dans des secteurs particulièrement riches en roches volcaniques et mantrent une association spatiale avec des zones de failles majeures.Les gites de type ""veine de quartz"" correspondent à des réseaux de complexité variable de veines de quartz-carbonate-pyrite se développant dans des zones de cisaillement inverse et des fractures de tension. Ils se concentrent dans les régions dominées par des roches volcaniques mafiques et s’associent fréquemment à de petites intrusions porphyriques felsiques syn- a tardi-tectoniques. L’altération associée ace type de glte est postérieure à la phase majeure du métamorphisme et consiste en une carbonatisation, une sericitisation et une pyritisation des épontes. La mise en place de ces gites est tardive par rapport à l'évolution géologique de l'Abitibi.Les gites d' or de type pyriteux consistent en des lentilles de sulfures massifs déformes, des zones d' abondantes veinules pyrite uses syntectoniques, et des zones de pyrite disséminée. Ces gites se retrouvent dans des empilements contenant surtout des roches volcaniques felsiques qui sont transformées en schiste à séricine pres des gisements. L’altération a l’umineuse pre-metamorphique associée a ce type de glte a donné naissance, lors du metamorphisme regional, a la sericite, a 'andal ousite, a Ia lcyanite et au chloritoi""de; par la suite, les alumino-silicates ont été affectes par une alteration retrograde tardive. Ces gites representent probablement des depOts de sulfures massifs volcan gènes déformes, mais la chronologie de la mise en place de l'or dans ceux-ci est encore mal comprise.Les caractéristiques géologiques propres à chacun de ces types de gites reflètent des conditions de formation différentes: le type ""pyriteux"" montre une histoire génétique polyphasée, incluant une étape pre-tectonique alors que le type ""veine de quartz"" s’est développe au cours d’une seule phase tardi-tectonique."

Jan 1, 1990

By J R. O Walli

Large production shafts can be successfully sunk through the ubiquitous Blairmore formation of southern Saskatchewan by employing the freezing process and by the installation of a cast iron tubbing lining. Although the freezing technique for shaft sinking and the use of cast iron tubbing to preserve the shaft are new to the North American continent, these procedures have been employed in Europe for the past eighty years. More than 200 shafts, covering a wide variety of ground conditions, have been sunk by the freezing process, and most of these have been lined with cast iron tubbing. The No. 1 shaft of International Minerals and Chemical Corporation, near Esterhazy, Saskatchewan, comprises the first major example in Canada of the employment of European methods to overcome extremely difficult ground conditions. The Blairmore formation was solidified by the deep freezing process, employing a lithium chloride solution as the refrigerant, with input temperatures ranging to -55°F

Jan 1, 1964

By A. Christoffersson, T. Nillson-Wullf, H. R. Manouchehri

"Mining industry has been the building blocks for human development through millennia and will continue to play its role in sustainability and meeting society’s needs for raw material. In the way towards sustainability, the next generation of efficient and heavy duty of Sandvik’s crushers, CH860 and CH865, are introduced for efficient crushing. As the secondary, tertiary and/or pebble crusher, these new crushers are designed to over perform in tough mining environment. Featuring higher crushing forces relative to the mantel diameter and 500 kW motor, combined with advanced automation system, i.e., sophisticated HydrosetTM and Automated Setting Regulation (ASRTM), combined with overpressure system with dedicated air supply in dust collar, etc., the new crushers provide higher safety, productivity, and reliability with the same foot-print of conventional cone crushers.Since crushers are more energy efficient than mills it makes sense to effort in fine crushing to save energy and protect environment. That has been the logic behind development and introducing stronger and more efficient crushers by Sandvik. The results on crushing hard iron and gold ores by CH865 have proven its efficiency in fine crushing at a higher productivity, availability and reliability rates through increasing throughput for defined size fraction and extended crushing chamber liner life.Within this paper the performance of the CH865 to deal with two different ores are presented discussed with a glance at how the downstream milling process can be benefited by saving energy and reducing the operation cost. In plant practice, the implementation of the new CH865 provides between 25 and 30% of the crushed ore in the size range of first step milling, i.e., < 2 mm, that offers opportunity for reduction in energy consumption in milling and even changing the process plant configuration by directly forwarded that part to gravity separation. Furthermore, potential of converting the rod mill to ball mill to improve productivity has been considered by plant engineers. Furthermore, some potential applications for such efficient crushers are brought into considerations and discussed. The new developments provide about 30% higher crushing force to efficiently deal with competent ores and pebbles. The CH860 and CH865 crushers are well suited to replace conventional secondary and tertiary crushers respectively; nevertheless, CH865 is virtual option for pebble crushing in SAG and AG milling circuits."

Jan 1, 2016

By S. Foged

Umicore and MWH jointly demonstrated that mechanical dewatering of goethite and neutralised tailings significantly increased the life of a 30 ha tailings pond and improved the operation of the pond. Umicore operates one of its zinc production plants in Balen, Belgium. As part of its production process, an excess of neutralised and goethite¬containing tailings is generated. These have historically been stored inside large lined ponds. As the storage area of the current goethite pond was nearing its capacity, Umicore studied the potential for an extension to the existing embankment. However, this extension would face intense regulatory scrutiny, because the environmental and safety impacts were considered important. Together with Umicore, MWH suggested and investigated an alternative treatment approach consisting of mechanical dewatering prior to storage. A feasibility study was prepared where wet storage was compared to dry storage. Differences in safety risks, environmental impacts and economic costs were outlined. The study demonstrated that the life of the tailings pond could be increased from 6 to 22 years, seriously reducing the environmental impacts and safety risks at no significantly higher cost than would have been incurred with the continued operation of the existing pond. The results of the study are presented in this paper.

Jan 1, 2006

By M D. Winning

The historical development of the elemental sulphur recovery industry in Western Canada is reviewed for the period 1952 to 1965. A brief technical description of a typical modified Claus sulphur recovery unit is presented. Some predictions are made concerning the future of the elemental sulphur recovery industry in Western Canada. THERE are evidences of sulphur or its compounds having been used for religious and medicinal purposes as far back as we have a recorded knowledge of history. As typical examples, sulphur was burned as a sort of inverse incense to drive away evil spirits at religious festivals, sulphur ointments were used by the early Egyptians to cure eye ailments, and hot sulphur-spring water was used as a cure for a variety of ailments. Thermopyle was called "Hot Gates" be-cause of its fame as a spa as well as a mountain pass. The Romans discovered the sulphur deposits in Sicily and mixed sulphur with bitumen for incendiaries; and, of course, anyone familiar with the travels of Marco Polo knows about the Chinese development of gunpowder, which contains sulphur. In some aspects things haven&apos;t changed much today. We still use sulphur-bearing ointments, and we still use the hot sulphur springs such as the one at Banff in Western

Jan 1, 1965

By Jos. Kalbhenn

MR. G. G. BOWSER: Mr. Kalbhenn&apos;s paper is an excellent one and is a concise description of a very interesting piece of work. It is well known that a great deal of preliminary study was given to this job before the final plans were made. It is due to this thorough preparation .chat the work progressed so satisfactorily, smoothly, and safely. The ideas carried out in the construction of the hardwood pack, timbered compartment, inclined raise, loading chute, and steel-boomed room, all contributed to a successful conclusion of the work. The extra care in being certain that the compartment shafts were well timbered was especially necessary on account of the difficult blasting conditions. In other words, the foundations .of this job were well and truly laid. The blasting in this work was very difficult due to the nature of the Strata. Working under an ever precarious roof condition and completing .this job with only two lost-time accidents is a record of which to be proud. The shaft men engaged on this work are also due for praise. I regret I did not visit this work while it was in progress. It was not in lack of interest. This, however, more or less proves that the blasting end .of this job went along with practically no trouble. I have seen the nature of the rock, as I made several visits to the tunnels while they were being put through from the Phalen to the Harbour seam. According to figures in Mr. Kalbhenn&apos;s paper, the explosives consumption works out to 1.61 pounds per cubic yard of rock in the solid, or 0.8 pounds per ton. The explosives consumption in the tunnels ran from 2.86 to 3.46 pounds per cubic yard or an average of 1.58 pounds per ton of rock. Of course, the rock in the shaft was blasted in the most economical way possible, as far as powder costs are concerned, as the face advanced at close -wright angles to the strata and gravity was acting with the explosive. The tunnels were driven nearly &apos;end on&apos; the strata and bottom holes had to be lifted, and I believe there was some re-drilling of ribs left in the floor. I would like to congratulate Mr. Kalbhenn on his very fine paper.

Jan 1, 1944

By A. Holland, T. Krumins, E. Olin, J. F. M. Castilleja, J. Geldart, C. Fleming, I. Jackman

A flowsheet has been developed to treat the flotation tailings from a copper mine in Mexico to recover gold and silver by cyanidation and carbon-in-pulp (CIP). The plant will treat ~15,000 t/day of a 60:40 blend of current flotation tailings and the mine’s historic tailings. The tailings also contain a significant amount of cyanide-soluble copper, and the economic viability of the project is strengthened by recovering most of the copper and cyanide associated with this process. The solution and solid phases in the CIP tailings will be separated in a counter current decantation (CCD) circuit and the CCD solution overflow will be treated by a SART Process. Copper precipitates as a salable copper sulphide product in the SART Process and the cyanide that is associated with the copper complex is regenerated as free cyanide. After SART, a portion of the SART product solution will be recycled to leach to reuse the free cyanide, while the remaining solution will be used as wash water in the CCD circuit. Incorporation of the SART Process in the flowsheet allows the CIP circuit to be operated aggressively as a gold plant, which means most of the silver in solution passes through CIP to SART. Silver co-precipitates with copper in SART and is recovered very efficiently with the copper sulphide by-product. Incorporation of SART also allows the leach and CIP circuits to be operated with relatively high levels of free cyanide, which enhances silver leach kinetics and helps keep copper from loading onto the carbon in CIP. The flowsheet was developed in the laboratory and successfully demonstrated in a fully-integrated pilot plant in 2018.

Jan 1, 2019

By Scott A. Trebilcock

Nautilus Minerals Inc the world?s leader in exploration and development of deep ocean mineral resources is today focused on the recovery of high grade copper-gold from in seafloor massive sulphide mineralization. These mineralized belts, analogous to land based volcanogenic massive sulphides (VMS) deposits are located near tectonic plate boundaries of the Western Pacific and around the world. Nautilus; first development project is Solwara 1 located in benign waters in Papua New Guinea. Since 2006 the company has completed detailed environmental and geological studies at Solwara 1, culminating in a number of world firsts, including the first Environmental Permit for a deep ocean mineral project and the first NI 43-101 compliant seafloor massive sulphide resource statement. Nautilus has relied heavily on proven deepwater technologies from the oil and gas industry in the design of the first mineral extraction system. Pipeline trenching units, workclass ROVs, deepwater production risers and drill cutting removal systems will all be adapted at Solwara 1. Key contractors to the project have all been selected for their deepwater experience, creativity and determination to launch this new industry. Innovation is at the forefront of Nautilus? success to date. This paper gives an overview of the Solwara 1 development and describes the exploration and production technologies adapted for seafloor mineral extraction.

May 1, 2010

By D. M. Baird

"Enormous deposits of gypsum of exceptionally high grade are readily accessible in southwestern Newfoundland. Coming large-scale production from one of these is resulting in renewed interest in deposits which have been known for more than a hundred and twenty years. General stratigraphy and structure of the Carboniferous rocks in which the gypsum occurs are de-scribed. The stratigraphic position of the basal gypsum-anhydrite zone is described. This massive evaporite horizon, which reaches a thickness of about 1,0001 feet, appears at Fishels-Heatherton, where it is largely undeveloped, and again on the nose of an anticline east of Flat bay, where a present production of 20,000 to 40,000 tons per annum is soon to be expanded to make it one of Canada's major producers. Detailed descriptions are given of the several types of gypsum, the relation of the gypsum and anhydrite, and the distribution of sodium chloride in the evaporite beds, and the bearing of all these on the origin of the gypsum are discussed. Brief reference is made to relation to world markets, mining and transportation, grade, and reserves."

Jan 1, 1959

By V. Gangrade

Recirculation is the major concern associated with the utilization of booster fans. In controlled recirculation, a portion of the return air is purposely mixed with the intake air and the mixture is directed towards a working district, while the air quantity and gas concentrations in the air are closely monitored and managed. The objectives of this study were to determine the gas concentration in intake and return airways during controlled recirculation, and to determine the recirculation fraction for multiple headings. Experiments were conducted in a laboratory model to determine the effect of controlled recirculation on the quality of air circulated through the working faces. Preliminary results showed that recirculation is beneficial to ventilation planning because it reduces the build-up of air contaminants at the working faces and reduces the overall power consumptions. The experimental results were used to quantify the recirculation fraction and to calibrate ventilation models of the laboratory model. These models are used to simulate the controlled recirculation and to predict the gas concentrations in multiple headings.

Aug 1, 2013

By Marcelle A. Hauseux

"The Turgeon Lake granite lies 5 miles north of Baie Johan Beetz, Quebec, at the eastern margin of the Grenville Province. The rocks are classed as granites, granulites, quartzites, biotite schists and gneisses, and amphibolites. The granite's uraniferous character is manifested by phosphuranylite, uraninite, and metamict .zircons associated with magnetite. Field anomalies occur in irregular pods, conformable with the tectonic foliation, in bands roughly paralleling sedimentary bedding. Associated features diagnostic of uraniferous granite are smoky quartz, brick-red feldspar, magnetite and a coarse to pegmatitic grain size. The granite is chemically and physically heterogeneous. Metasediment-granite contacts are diffuse or sharp, and usually conformable to bedding. The regional foliations within all rock types are coherent, and sedimentary structures are often preserved within both metasediments and granite. Autometasomatism probably was a strong granitization agent.A uranium reconcentration into fold-axial zones from original sediments which have been highly granitized during at least two phases of folding is suggested from the available data."

Jan 1, 1977

By A. Desbiens, A. Pomerleau

During the summer of 1994, a new PID-based control strategy was installed on line B of the grinding circuit at the Kidd Creek Division of Falconbridge Ltd. Part I of this paper described the methodology used to select the appropriate control strategy using a phenomenological dynamic simulator. Part II presents the implementation of the control strategy. Prior to the controller installation, it was necessary to solve various problems related to the process, such as a cyclic behaviour of the rod mill feed tonnage, a problem related to the mill water source and the calibration of the flowmeters. Once these problems were solved, the control strategy was accomplished in two steps. Step 1 corresponds to the installation of control loops to regulate the pump box level and the cyclone overflow density. Step 2 describes the implementation of a loop to control the cyclone feed density. According to Part I, a loop to control the circulating load is also part of the original design. However, reasons are given to explain the rejection of this loop. For both steps, technical procedures such as filtering, process identification and controller tuning are detailed. Finally, the operator’s interface is briefly described.

Jan 1, 1997

By K. Svens, M. Lahtinen, L. Lehtinen

"Outotec&apos;s direct leaching process is an atmospheric leaching process for sulphidiczinc concentrates. The direct leaching process, based on special leaching reactors developed by Outokumpu and leaching know-how, is the most economical way to produce electrolytic zinc. The newest industrial-scale application of Outotec&apos;s direct leaching process will be started up in 2008 in China at Zhuzhou smelter. The process isintegrated to the existing production plant, replacing part of the old production facilities by modern technology and increasing the production capacity significantly. The process equipment supplied by Outotec includes also tailor-made reactors designed on the basisof the work and experience of Outotec Research Centre."

Jan 1, 2008

By M. M. Holgate

"Porosity neutron deflection scales can be derived more easily by cumulative correlation than by the conventional method of plotting corresponding points on a graph. The micro-log can be used as a porosity datum for the neutron log by transforming the permeability cut-off it shows to a porosity cut-off by a permeability-porosity function obtained from core analysis. Porosity footage values calculated in this manner from the neutron log are within 20 per cent of core analysis values."

Jan 1, 1960

By Jr. Fackler

The ionization potentials of gaseous Group 11elements are similar, with Au(0) being 1.5 eV greater than the next highest member of the group, Cu(0). The ionization potentials are all very much greater than the alkali metals, making these ?coinage? elements rather unreactive to chemical oxidation. Ionization from the first oxidation state shows a different pattern, with Ag(I) being the most difficult of the Group 11 ions to lose an electron. Gold(I) is noble and only normally oxidized in the presence of strongly coordinating ligands such as thiols or cyanide. Gold(I) compounds are 2-, 3- and 4- coordinate, with 3-coordinate species generally showing visible photoluminescence under UV excitation. Dinuclear Au(I) compounds with strongly coordinating S or C ligands can be oxidized to form isolable metal-metal bonded Au(II) compounds which are often readily isolable. Many have been structurally characterized. T he ease with which electrons are lost from closed shell dinuclear sp ecies (with anti-bonding M-M interactions) increases when metalmetal bonded compounds are formed. T his observation was made by our group with oxidative-addition studies of dinuclear gold(I) ylide complexes. It was superbly demonstrated recently by Cotton?s group who reported the isolation and characterization of a dinuclear closed shell transition metal species which is more readily oxidized than cesium. Trinuclear Au(I) pyrazolates, TR(pz), carb eniates, TR(carb), and benzylimidazolates, TR(bz), are well known and undergo electron loss through oxidative addition forming Au(I,III) mixed valence species and ultimately trinuclear Au(III) species. Au(II) species are absent from isolation in these oxidations. These carbeniates and benzylimidazolates also are excellent bases for metals ions such as Tl(I) and Ag(I). The acidic, neutral trinuclear compound [Hg(C6F4)3]3 also interacts with these bases. We have also shown that the neutral organic pi acids C6F6 and TCNQ form stacked pi-acid pi-base products with the trinuclear Au(I) compounds. In this paper, the structure of the octafluoronaphthalene acid-base product will be described. It displays a feature not observed previously in that the product is photoluminescent with a bright yellow emission. The 3.5 ms lifetime is very long and reminiscent of the long lifetimes observed by Balch for the stacked methyl,methoxy Au(carb). The electrochemical oxidation of tetragold(I) clusters, [Au4(form)4] have been studied in 0.1 M Bu4NPF6/CH2Cl2 at Pt working electrode at different scan rates. Three waves are obtained at 0.75, 0.95, and 1.09 V vs Ag/AgCl at scan rate 500 mV/s. The potential of the three reversible waves is independent of the scan rate in the range 50 mV/s to 3 V/s. The current at the third wave is larger than those at the first two waves. These tetranuclear species app ear to be effec tive catalyst precursors for the oxidation in air of CO. Introduction. The electronic structural relationships of the coinage elements and the alkali metals are similar in the sense that each have a [closed shell]ns1 configuration, yet their ionization energies (Table) and chemistries are clearly vastly different. The Group 11coinage elements have an underlying nd10 level immediately below the ns1 level. Unlike the alkali elements, ionization leaves the filled d electron shell the next accessible for further ionization. The coinage elements are all relatively ?noble?, much less reactive to environm ental conditions than the alkali metals. With the coinage elements, oxidation becomes very much dependent upon the types of ligand s availab le to bo nd to the ionized state.

Oct 1, 2003

By M. Marchese

It is no secret that scarcity of fresh water is an issue that at a global level in the years to come will have a major impact on the business landscape. A number of projects, beyond the mining sector, could remain on paper only due to this. At the same time, this situation is seeing the rise of new business opportunities, such as development of technologies for more efficient usage of water, water recycling, and desalinization of sea water. Despite that most of Chilean mining facilities are located in the driest area of the world, business has developed strongly and actively for more than a century. However, the negative effect on the water reservoirs and the environment is, lately, resulting in the reduction of the authorized water rights. Holding Water Rights for any given volume does not guarantee that the resource will be available when needed. A recent report from the United Nations on global climate change indicates that global warming can be directly related to changes in the natural and human environment. Chile would not be an exception. The reduction in snow levels in the high Andes and reduced rainfall during the so called "Bolivian winter", have directly affected the replenishing of the underground water reservoirs in the lower parts of the valleys, where most of the extraction of the resource takes place. Mining facilities shall be designed to reduce potential environmental effects, using proven technologies, and considering the best practices available. These measures shall constitute a complete structural framework for the environmental impact assessment (EIA) of the Project. The measures to prevent and mitigate the impacts on the water resources shall be considered during the design stage of a mining project. Current and future mining projects in Chile are conscious that the increasing pressure on the limited water resources is becoming unsustainable, and are already facing the water scarcity and social pressure by implementing sea water desalination plants, including long pressurized pipelines to the mine sites (e.g. Escondida, Candelaria, El Morro, Regalito). This paper presents, in summary, an analysis of the present and potential future scenarios.

Jan 1, 2007

By A. G. Mattes

This paper presents an overview of passive, engineered, biologically-based anaerobic bioreactor (ABR) treatment systems of the sort that can be used to remove dissolved copper from mine wastewaters. The paper begins with a brief history of the origins of this treatment technology and continues with a discussion of principles of engineered wetlands (EWs, advanced kinds of constructed wetlands, CWs) and the use of vertical sub-surface flow (VSSF) varieties that contain pulp & paper biosolids as the reactive medium for EW cells. A brief outline of a procedural methodology used in evaluating the potential for biological treatment on a site-specific basis is also included. An introduction to the microbiology of passive biologically-based treatment systems is followed by some recent research results in the general area of wetlands and ABR research. The paper concludes with a brief discussion of several sites known by the authors to have successfully (or not) demonstrated the potential of this treatment option.

Jan 1, 2007

By Bahaa Hussein

Considerable number of methods and procedures has been introduced for trending and progress reporting of engineering, procurement and construction projects. This paper introduces a novel method, designed to augment the set of indices for measuring schedule performance. The concept behind the developed method is to provide early warning by dynamically evaluating the schedule cumulative impact of construction projects. The proposed method is designed to highlight the gradual deterioration in schedule status resulting in a cumulative impact due to the aggregation of small delays encountered during the execution of non-critical activities, and can be used as an add-on utility to existing software systems that perform CPM scheduling. The proposed method is based on a developed formulation for quantification of the Schedule Compression Index, which takes into consideration the remaining project activities durations. The index is developed based on periodic comparisons of ?Current Schedules? and the project ?Baseline Schedule? using the summation of the remaining activities durations. A numerical example is presented to demonstrate the application and capabilities of the developed method. It is expected that the developed index together with other schedule performance indices would be of value to decision makers and members of project teams.

Aug 1, 2013

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