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By D. R. Lentz, J. A. Walker

"Abstract -The Flat Landing Brook Zn-Pb-Ag deposit of the Bathurst Mining Camp occurs within a narrow thrust-bound nappe containing felsic volcanic and volcaniclastic rocks of the Tetagouche Group. Within the host nappe, the Tetagouche Group is represented by the Nepisiguit Falls Formation and the overlying Flat Landing Brook Formation. The Nepisiguit Falls Formation is divided into two members: quartz- and quartz-feldspar-phyric volcaniclastic rocks ± minor lavas (Grand Falls member), and aphyric, fine-grained volcaniclastic rocks (Little Falls member). The Flat Landing Brook Formation consists of aphyric rhyolite flows and interbedded pyroclastic rocks. Several gabbroic intrusions occur in both the footwall and hanging-wall sequences. These gabbros locally cut out the mineralized horizon at shallow levels, and are considered to be feeders to tholeiitic basaltic flows (Forty Mile Brook member) of the Flat Landing Brook Formation. The Flat Landing Brook deposit has many of the characteristics typical of volcanogenic massive sulfide deposits occurring within the highly productive Nepisiguit Falls Formation in the eastern part of the Bathurst Mining Camp. Mineralization occurs within or at the top of the Grand Falls member and comprises four or more massive to semi-massive sulfide lenses that vary in thickness between 3 and 5 m. Massive lenses are laterally gradational to, or underlain by, zones of disseminated sulfides up to 38 m thick. The deposit contains an estimated resource of 1.7 Mt grading 4.9% Zn, 0.94% Pb, and 19.54 g/t Ag to a depth of approximately 150 m. From 150 to 300 m below surface, mineralization is low grade and mostly disseminated. However, below 300 m, ore-grade (>10% Pb+Zn) massive sulfide lenses have been intersected over mineable widths. Oxide facies iron formation overlies and (or) grades laterally into the sulfide lenses. The oxide facies has strong positive Eu anomalies and gently sloping rare earth element (REE) profiles suggesting that it was formed from relatively hot acidic fluids that had interacted with felsic volcanic rocks in the footwall. In contrast, the silicate facies iron formation that is more distal to sulfide accumulations has very weak positive Eu anomalies and gently sloping REE profiles, suggesting either cooler hydrothermal fluids or dilution of the hydrothermal component by detrital material. Hydrothermal alteration has affected most footwall rocks. Most notably, albite-destructive alteration has resulted in Na2O depletion, whereas mass addition of K2O is manifested in the formation of sericite (white mica). In more intensely altered quartz- and feldspar-phyric volcaniclastic rocks of the Grand Falls member, feldspar destruction is accompanied by chlorite alteration, producing quartz-phyric rocks similar to those in the footwall of many Bathurst Camp deposits."

Jan 1, 2006

By Philippe Ribagnac, Bruno Courtaud, Jean-Marie Lambert, Valérie Weigel

Mabounié is a polymetallic deposit in Gabon containing niobium (1.2 wt.%), tantalum (0.03 wt.%), rare earth elements (REE) (1.4 wt.%) and uranium (0.03 wt.%) that are mostly carried by pyrochlore minerals. The classical route for niobium recovery is a pyrometallurgical process that consists of pyrochlore flotation, dephosphorization of the niobium concentrate and aluminothermy to obtain ferro-niobium. Pyrochlore concentrates can also be treated by a hydrometallurgical process with a mixture of sulfuric and hydrofluoric acid leaching followed by solvent extraction to separate niobium and tantalum. However, the first process does not allow recovering REE and the second one is not environmentally friendly because of the use of HF. ERAMET is looking for new opportunities on strategic metals market and has recently developed a hydrometallurgical process for the recovery of all these metals based on a sulfuric acid treatment of the ore (Donati, Courtaud, & Weigel, 2014). As for most of the oxidized ore processes, the major impurity is iron (~30 wt.%). Thus, in this hydrometallurgical process, the question arises of the elimination and stabilization of the iron as residue. The iron in solution is ferrous; goethite precipitation seems the most adapted crystalline form. Lab and pilot tests have shown kinetics of precipitation of 6 g.L-1.h-1 at pH 4.5. To reduce the salt discharge, sodium-jarosite form is more adapted, but at pH 2, 95°C only 30% of iron is precipitated in 5 hours, compared to 100% in goethite form at the same time and pH 2, 80°C. Different ways of oxidation were tested, air, pure O2, activated carbon, without drastic effect. The more efficient was ozone use, at room temperature; the kinetics of oxidation is five time faster than the other ways with 30% of sodium removed from the solution.

Jan 1, 2016

By Kazutoshi Haga, Batnasan Altansukh, Atsushi Shibayama, Ryuji Oinuma

"Recently, the arsenic grade in copper ores has been increasing year by year. Arsenic bearing minerals (enargite (Cu3AsS4) and tennantite (Cu12As4S13)) coexist with typical copper minerals such as chalcopyrite (CuFeS2). The removal of arsenic from copper ores that contain relatively high arsenic content is essential due to its adverse impact on the environment and the resulting economic consequences. In this study, arsenic removal and dissolution behaviour of Cu and As from enargite (Cu3AsS4) were investigated using ferric sulphate (Fe2(SO4)3) solutions containing sodium chloride under high pressure oxidation conditions. The effects of numerous parameters including the concentration of Fe2(SO4)3 and NaCl, temperature, total pressure, leaching time and particle size were studied while other variables such as pulp density and stirring speed were fixed at 100 g/L and 750 rpm. The results showed that more than 60% of the copper was dissolved in a 0.1 M ferric sulphate solution under the high pressure oxidative conditions, whereas the leaching rate of arsenic was less than 20%. SEM observation revealed that elemental sulphur was deposited on the surface of enargite forming a passivation layer and the residue was agglomerated. Those phenomena may cause a decrease in the copper leaching rate. It was found that more than 80% of copper was dissolved in the ferric sulphate solution in the presence of 0.34 M sodium chloride under the conditions optimized, whereas the dissolution of arsenic in the mixture did not exceed 2%. XRD analysis of the solid residues from the leaching experiments used ferric sulphate and mixtures of ferric sulphate and sodium chloride showed arsenic to be present as scorodite (FeAsO4).INTRODUCTION In recent years, there has been an increase of the arsenic (As) content of copper ores due to the gradual depletion of high grade copper ores. In some copper deposits, arsenic occurs in the form of minerals such as enargite and tennantite. The removal of arsenic in ores containing copper is critical to the production of pure copper and the management of the environmental challenges caused by the smelting process. Due to the environmental risk caused by arsenic emission and the deteriorated quality of the copper product, smelting of enargite concentrates is not an effective method for the extraction of copper (Padilla et al., 2010; Safarzadeh et al., 2014; Long et al., 2012). Therefore, a number of studies have been carried out to develop arsenic removal technologies from copper ores using various methods such as hydrometallurgy (Curreli et al., 2009; Tongamp et al. 2010), pyrometallurgy (Dalewski., 1999; Padilla. et al, 2012) and bio-oxidation (Ehrlich, 1964; Sasaki et al., 2010). Several hydrometallurgical leaching processes like sulphuric acid, alkaline sodium sulphide and sodium sulphate and ferric sulphate leaching have been developed to treat enargite ores and concentrates. The alkaline sodium sulphide leaching process has been developed for the removal of arsenic from enargite (Anderson, & Twidwell, 2008; Parada et al., 2014). The mechanism of the dissolution of arsenic from enargite in sodium sulphite solution is"

Jan 1, 2016

By A. de Ville d’Avray, G. Guezennec, P. Wavrer, E. Braak

The aim of the European CEReS project was to develop an innovative copper recycling route based on the coprocessing of coal production waste by bioleaching and printed circuit boards (PCBs) from Wastes of Electrical and Electronic Equipment (WEEE). Coal waste is processed by bioleaching in stirred tank reactors, and the resulting bio-lixiviant solution is used to extract copper from PCBs pre-treated by catalytic cracking. Copper is then extracted using solvent extraction, stripping and electrowinning. The whole process flowsheet combines thermal, biotechnological, physical and hydrometallurgical operations. Once the process concept has been validated at laboratory scale, a simulator of the whole process has been built in the USIM PAC software platform. The tool enables to improve the analysis of the results of the lab-scale experiments and to design industrial-scale scenarios by simulation. The results of such simulations allow to estimate the economical interest and to perform environmental impact assessment. After presentation of the CEReS project objectives and main results, the paper describes the methodology used to build the simulator and define the scenarios corresponding to feasible process routes. The main results of the simulations are then presented with technical, economic and environmental point of views. INTRODUCTION Because of rapid technological innovations in the electronics industry, electronic waste represents the fastest growing waste stream in the world, especially in developing countries (Işildar et al., 2018). Meanwhile, the global copper demand is expected to go on rising in the future. As significant amounts of copper are present in end-of-life printed circuit boards (PCBs), it becomes a necessity to develop efficient copper recycling routes. Metal refining from e-waste is traditionally performed by pyrometallurgical processes. However, the hydrometallurgical processing of PCBs, which has been shown to be technically feasible at laboratory scale with a wide range of leaching reagents, could be a less energy intensive and more flexible alternative (Tuncuk et al., 2012). However, a large amount of leaching reagent is required to leach the metals from PCBs.

Jan 1, 2019

By I. Jackman

"Gold is present in different forms and associations in different ores. Flotation is used to recover gold and minerals associated with gold, but the applicability and type of flotation vary. The purpose of flotation in a gold recovery plant is largely dependent on the mineralogical association of the gold, and environmental and economic considerations. In this paper, the role of flotation in the recovery of gold is reviewed. The paper will describe examples of gold recovery by flotation including flotation of native gold, gold associated with sulphides including specifically copper sulphides, gold associated with tellurides, gold ores containing carbonaceous material and gold contained in tailings.INTRODUCTIONFlotation is widely used in the recovery of gold. However, the objectives and the mode of application are quite variable dependent on the type of ore, the gold association(s), other metal values, marketing considerations and environmental requirements. In this paper, a range of different applications of flotation incorporated in the recovery of gold are discussed. The reasons for each particular application are outlined and metallurgical results are presented.The mineralogy of the ore and the gold associations are fundamental influences on gold recovery. The use of flotation to concentrate gold is dictated by the mineralogy of the ore and gold. The fundamental factors are mineral/gold size, liberation size, association of the gold and type of gangue minerals or other valuable minerals. Gold can exhibit a range of sizes in a host from relatively large size (+50 µ) to refractory size (1 µ and sub-micron size). Similarly, the gold can occur in a number of phases in the same host. For example, the gold was present as petzite (AgAu telluride), calaverite (AuTe2) and native gold in a gold telluride ore and each of these minerals was associated with the pyrite host.Understanding the gold mineralogy and association is important in establishing the correct process route. The gold mineralogy is established by good mineralogy, use of diagnostic tools such as diagnostic leaching and assay by size fraction analyses and basic metallurgical testwork."

Jan 1, 1995

By C. F. Harris

Following the initial development of the zinc-lead blast furnace, efforts have been directed both at increasing the scope of the process and increasing the cash return. The paper reviews the process developments which enable the process to smelt efficiently a range of material which encompasses high-grade zinc sulphide concentrates. mixed concentrates, Waelz oxide, zinc ashes and other materials blended to give a furnace feed ranging from 25 to 65% zinc and from 1 to 25% lead, with a copper-lead ratio exceeding 1 to 8. The paper also reviews the process developments which have enabled the capacity of a furnace and condenser system of standard size to be boosted from 30,000 to 80,000 tonnes/annum. The benefits achieved are used as a justification for continuation of the development of the zinc-lead blast furnace. Predictions are made of the benefits expected from further developments.

Jan 1, 1979

By J. O. Marsden

Over the past decade, the copper industry has been through an extended downturn followed by several years of sustained high copper price. A number of new technologies have been developed over the past 10 years aimed at reducing costs by decreasing energy, labor, and materials requirements, or by increasing metal recovery. The energy intensity of different copper extraction routes and different technologies varies considerably and this has a significant impact on the economics of extraction. Based on average ore grade materials, the total energy for the extraction of copper typically varies from about 24-26 MJ/lb (6.7-7.2 kWh/lb) for the mining, crushing, milling, flotation, smelting and refining route to about 14¬16 MJ/lb (3.9-4.5 kWh/lb) for the mining, crushing, heap leaching, solution extraction and electrowinning route. New technology developments are providing opportunities for significant reductions in energy consumption for copper extraction, representing energy savings up to 20-25% in some cases. In addition, in many cases, these new technologies have introduced environmental, safety and health benefits over the incumbent technology. Some of these technology developments have been more successful than others, and many hold great promise for application in the coming decade. This paper provides an overview of the technology developments that have occurred, and explores the underlying reasons behind successful implementation.

Jan 1, 2007

By Baisheng Nie

The process of gas diffusion through coal particles and the mathematical physical model under the third kind boundary condition was determined to obtain the rules of gas diffusion through coal particles of different sizes. The analytical solution of the equation was obtained by the Method of Mathematical Physics. The parameters of analytical solutions and the implications of parameters were analyzed. The Biot criterion (Bi) and the Fourier criterion (F0) of mass transfer can represent and reflect the features of gas diffusion field of coal particles. Moreover, the measurement method of gas diffusion coefficient and surface mass transfer coefficient is introduced and an example of measurement is given. The achievement can provide the support to prevent disasters related to methane in coal mines.

Aug 1, 2013

By E. Dernedde

A few studies have suggested that the rate of adsorption of hydrogen fluoride on smelter grade alumina is determined by kinetic factors. However, no performance equation for dry scrubbers has appeared in the literature so far. Experimental data from a pilot dry scrubber with co-current flow were compared with results of kinetic models of adsorption, film diffusion and pore diffusion. The pore diffusion model was deemed the most appropriate. It was transformed into a performance equation for steady-state operations of dry scrubbers by the inclusion of the alumina recirculation. Operating results of industrial dry scrubbers with co-current flow were successfully evaluated by means of the performance equation. The average fluoride content of the alumina was also estimated by using the pore diffusion model.

Jan 1, 2011

By Garth D. Kirkham, James P. Siddorn, Hendri Falck

"Abstract - As an integral part of the Geological Survey of Canada’s EXTECH III Project, a threedimensional computer model has been created of the Con and Giant gold mines in the Yellowknife Greenstone Belt. The Yellowknife Mining Camp has produced a great deal of gold (over 15 million ounces, or 400 000 kg) in the past sixty years and the prevailing assumption is that the mines are at the end of their lives. However, the potential for discovering additional resources using new ideas and technology, and maximizing use of existing data, offers an opportunity to sustain the old mining operations and maintain their contribution to the community.The objectives of this study included the compilation and creation of a three-dimensional Geographic Information System model (combining 3D subsurface data with surface information) to provide a framework for concurrent structural and alteration studies, and to encourage new exploration in the area. A secondary objective was to retain the data in digital format as a historical reference for future remediation efforts, and to document a portion of Canada’s rich mining history.The end result is a database and set of models that have been instrumental in facilitating further exploration in the area, as well as in developing targets for future exploration and mining activities. In addition, the EXTECH III 3D GIS model has made a valuable contribution toward the understanding of the arsenic remediation issues at the Giant mine, and has served as a tool in support of a variety of highly technical engineering studies and for communicating information and problems to the layman and community as a whole."

Jan 1, 2003

By Aalbert Zwijnenburg

One of problems connected with the use of gold/titania-based catalyst systems is the low yield in propene oxide (up to 2 wt %). It is shown that the low propene oxide yield is due to product inhibition. New options for propene epoxidation with hydrogen and oxygen are discussed. INTRODUCTION The direct gas-phase synthesis of propene oxide (PO), by the use of molecular oxygen, is still aimed for. Agbased catalysis is in principle possible, but selectivity at present is not promising. Highly dispersed gold on titanium containing catalysts show an extraordinary selectivity in the oxidation of propene to the corresponding epoxide (> 99 %), using a combination of H2 and O2 as oxidation mixture [1]. Additional studies of the epoxidation reaction have indicated several drawbacks of the Au/TiO2 catalyst. Firstly, the low conversion (1- 2 %) obtained under typical reaction conditions (atmospheric pressure, 323 - 423 K) cannot be increased by increasing the reaction temperature, because this leads to extensive by-product formation. Secondly, the low efficiency of hydrogen (relatively large amounts of water are formed) is hard to prevent. Finally, significant deactivation of Au/TiO2 catalysts within several hours on stream has been observed. Deactivation can be almost completely prevented by using dispersed TiO2 supports, such as TiO2/SiO2 and Titanium-Silicalite-1 (TS-1) [2]. In recent literature [2,3] a hydroperoxide-like intermediate has been proposed to be responsible for the selective epoxidation. This oxidising species is said to be formed over gold and subsequently used for epoxidation over the Ti-containing support. The support is responsible for the slow desorption of PO. One of the problems for future industrial application might be the low yield in propene oxide. Furthermore, the presence of minor amounts of by-products, not detected on lab-scale catalyst testing, might complicate the separation unit in an industrial process. The reason for the low PO yield over Au/TiO2-based catalysts will be discussed in this paper. Temperature Programmed Desorption (TPD) and micro-flow experiments have been carried out to study PO desorption and catalyst performance, respectively. A catalytic cycle is proposed together with its consequences for the maximum yield in PO. Finally, several process and catalyst options are discussed in view of potential future industrial application.

Oct 1, 2003

By S. E. El-Alfy, John Starkey

"The Iron Ore Company of Canada treats up to 125,000 t/d of iron ore at its Carol Concentrator in Labrador City, NF.A complete water balance study in the concentrator was done to show how to reduce the consumption of fresh water, to improve metallurgy in the magnetic separation (mag) plant, and to help reduce maintenance costs for the reclaim water and tailing pumping systems.The study showed that more than 60% of the water used in the mill was internally recycled dirty water from dewatering cyclone overflows, and that water reduction was closely tied to the effective use of these internal reclaim pumping systems. In addition, new operating parameters were set for the 4 -15,000 USGPM reclaim water pumps which should save over $100,000 per year in maintenance costs.IntroductionThe study described in this paper was set up for the purpose of lowering water usage in the concentrator, and to reduce tailing and process water pumping costs (operating and maintenance). Another benefit was also expected, namely, to improve magnetic separation efficiency through better water and density management of magnetic separator feed streams.The procedures selected to perform this work were: ( 1) to prepare accurate, as built flowsheets of the entire iron recovery process, including fresh and process water systems, (2) to calculate normal material balances in all circuits at full production, (3) to use the computer spreadsheet model so generated, to evaluate specific ways to reduce water consumption and (4) to re-evaluate metallurgical performance and operating parameters in the light of this information.Overall control of the 28 spiral iron recovery lines was found to be excellent because automated start up and shut down of the individual lines had been incorporated in the design from the start. Because production rates can vary due to sales requirements, mine and mill maintenance delays and hardness variance, the mag plant (which treats spiral tailings) must deal with a wide variety of operating conditions. Good water management therefore is a key item in achieving high recovery of the fine free magnetite which is too fine for recovery in the spirals.In order to make the study as accurate as possible, process data for major flows was reviewed by metallurgical staff and then by mill supervisors. The operating picture of the concentrator so generated was judged to be a good estimate of the mill at full production. By changing key inputs, the variance of process water demand and tailing slurry produced for several other operating conditions were studied.The usefulness of this exercise has prompted this present presentation to be made. Older plants by nature have undergone many revisions as operators have worked through ore changes, market changes, labour cost increases and the availability of new equipment, to improve their operation. Sometimes therefore it is necessary to stop and reassess what is happening in a plant in order to continue the never ending work of process optimization. The techniques used here were ideally suited to the gravity/magnetic concentration flowsheets used, but there is no reason why similar studies could not be done in other process plants.The authors of this paper hope that this experience at IOC will be helpful to others who face similar challenges in the pursuit of excellence in their processing plants."

Jan 1, 1995

By V. I. Lakshmanan

Rare earth elements and yttrium (REEs+Y) are being used in the making of hybrid electric cars, catalytic converters, wind power generators, LEDs, hard disc drives, flat panel displays, and portable electronics. Currently China produces more than 95% of REEs+Y, which has made REEs+Y a critical strategic resource. Process Research ORTECH Inc. (PRO) has developed the innovative mixed-chloride (HCl+MgCl2) solvent extraction processes for recovery of REEs+Y from their ores. The HCl leaching system provides the opportunity to regenerate the acid, while the presence of MgCl2 in the lixiviant enhances the activity of the hydrogen ion by orders of magnitude, making the lixiviant very aggressive and resulting in high recoveries of REEs+Y. Solvent extraction steps are used for separation and purification of REEs+Y from other value metals or impurities including iron, zirconium, hafnium, uranium, thorium, niobium, tantalum and titanium. Direct individual separation of REEs+Y in a mixed chloride system allows avoiding the additional process steps of precipitation and dissolution in HCl. The resulting process has a simplified flow sheet that is closed-loop and environmentally friendly.

Jan 1, 2014

By H. Nakano

The codeposition behavior of impurities such as Ag, Bi, Fe, Ni, Pb and Sb with Cu was investigated galvanostatically at 5-3000 A/m2 using a Pt cathode at 60 °C in acidic copper (I) chloride (cuprous chloride) solution at pH1-2 containing 1.0 mol/L of Cu+ and 4.9 mol/L of Cl-. The impurities were classified into two groups: Group I (Ag, Bi) which codeposits with Cu as a metal, and Group II (Fe, Ni, Pb, Sb) which is slightly involved in the deposited Cu in nonmetal form from the electrolyte. Silver and Bi in Group I behaved as more noble metals than Cu, and significantly codeposited with Cu, showing typical features of regular-type codeposition. When Cu was deposited dendritically, the Ag and Bi content in the deposit increased with increased duration of electrolysis as a result of decreased net current density caused by increased cathode area. The current efficiency for Cu deposition in impurity-free solution was 95-100% over 100-1000 A/m2, but it abruptly decreased at above 1000 A/m2 when the limiting current density of Cu was attained. Although Fe, Ni, Pb and Sb in Group II were involved to 0.01-0.02 mass% in the deposit, they had no influence on the current efficiency or morphology of Cu.

Jan 1, 2007

By Yan Jie

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

Jan 1, 2019

Mining Association of Canada ! Represent base and precious metal, diamond and oil sands producers as well as nonferrous metal smelting and refining ! Member companies account for the vast majority of Canada?s mineral and metal production ! Mining is a major economic sector in Canada ! 13% of total exports ($47 billion) ! Employment near 400,000 ! 4% of GDP The Kyoto Protocol ! November 18, 2004 -- Russia deposited its instrument of ratification with the United Nations ! The Kyoto Protocol entered into force on February 16, 2005 ! The Kyoto Protocol is now an international and legally binding agreement to reduce GHG emissions world wide ! Canadian GHG target = 6 percent below 1990 ! First Commitment period 2008-2012

Apr 1, 2005

By M. K. Kim

This study presents a framework for quality inspection of precast concrete components using the 3D laser scanning technique. As precast concrete-based rapid bridge construction is getting standardized, quality assessment of the precast concrete becomes critical for preventing any failures during the construction process. Moreover, as Building Information Modeling (BIM) gains popularity in the construction industry, autonomous and intelligent inspection systems are needed. Current method for quality control of precast concrete components, however, heavily relies on visual inspection and contacttype measurements, which are time and labor demanding. Also, storage and delivery systems of inspection information such as the procedures and results of quality inspection are lacking. To overcome these limitations of the current quality assessment technique for precast concrete, this study aims to develop a BIM-based framework for efficient quality inspection of precast concrete with the use of a 3D laser scanner. First, we formulate practical guidelines including detailed inspection procedure, selection of optimized scanner and scan location, inspection criteria, and data storage and delivery system. Second, to investigate the applicability of 3D laser scanning to precast concrete quality inspection based on the proposed framework, a case study inspecting quality of a lab-scale object assumed as precast concrete component is presented for detecting defects.

Aug 1, 2013

By J. N. Cram

"The comments given are to help allay generally accepted ideas that the handling of arsenic as arsenic-trioxide (As2o3J in and from off gas pyrometallurgical operation fumes is difficult, hazardous and expensive. It need not be any of these things if the basic and rather unique chemic3l and physical properties are understood and taken care and advantage of through present day technologies. These particular characteristics are:-(1) As2o3 sublimes and re-condenses, at a relatively low temperature;(2) As2o3 is, for practical in-plant purposes, insoluble in water at ambient temperatures and quite soluble in water just below the boiling point;(3) residual suspended and dissolved As 2o3 can be removed from water by complete dissolution with very little sulfuric acid, followed by the addition of small amounts of ferrous sulfate and calcium chlorate, with oxidation to the ferric and arsenite state and precipitation of an insoluble ferric calcium arsenate, thereby lowering the As2o3 content of solutions to acceptable levels. Even lower levels of non-toxic forms of arsenic solids and residual As2o3 in the water solutions can be attained by also using phosphate, and lime, along with the above.A background re past arsenic processing methods, present day operations, plus predictions re future trends, and hazards, are outlined."

Jan 1, 1979

By Scott Hean

"Environment and the economy are interwoven irrevocably. They need to be publicly discussed, and discussed often so that new approaches can be understood and developed - approaches which are complimentary, not confrontational.Discussion on the environment is timely, from the perspective of mining engineers and developers, from that of bankers and from their shared perspective as people concerned with enhancing the quality of life, the environment and the economy.This paper will touch on how what is called the ""environmental economy "" that has evolved has become entangled with regulatory and financial issues in a way that is dangerous for all of us. It will also look at some of the promising possibilities that a world-wide and continuing concern for the environment holds out for us.For many decades, British Columbia has provided some of the key examples of the intertwining of environmental and economic issues, and, very importantly, providing the people prepared to do something about them.Canada's first environment minister, the late Jack Davis, came from British Columbia. He led this country's delegation to the Stockholm Environment Conference in 1972, a conference that laid the groundwork of principles necessary to establish some international certainty as to the legal liability for causing trans-national environmental damage.Another British Columbian who was also a national environment minister, John Fraser - now the Speaker of the House of Commons - was one of the first to dramatize the importance of acid rain and force it into the international public arena.Some 20 years ago, British Columbians made Vancouver and their province one of the major centres of opposition to the Alaska Pipeline and Tanker System - with some justification, it now seems.That a British Columbian , then MP David Anderson, was given legal recognition to sue in a United States' court against a system that was either in U.S. territory or international waters was an important precedent in, and of, itself in terms of environmental law. That old controversy is now a very current case study - in terms of dealing with the question of liability.-"

Jan 1, 1991

By Desmond M. Connor

"The State of the EnvironmentRecent data from a State of the Environment report prepared in January 1991 and released in April (see references) , indicates that the physical and biological environment across Canada is deteriorating in some important ways. For example: • emissions and atmospheric levels of CO2 are rising at a rate more than 50% of the U.S. increase; global temperature continues to rise, especially during the last decade;• while S02 emissions have been falling since 1984, NOz has declined only slightly since that time; N02 in Canada rose 43% during 1970-87, compared with a 7% rise in the U.S.;• municipal discharges of phosphorus and BOD (biochemical oxygen demand) to fresh water have been rising steadily since 1983);• pulp and paper mill discharges to fresh and Pacific coastal waters have been rising, 1970-87;• migratory game bird populations (Prairie Mallard, Northern Pintail) have been declining for the last 20 years;• total per capita energy use continues to climb.The State of the PublicSimilarly, data from recent public opinion surveys shows that public concerns about the environment are either rising, or are remaining at a high level despite the competing claims of the economy and political events for attention.For example, Professor Reginald Bibby's national survey this year shows that Canadians rank our top three issues as theeconomy, the environment and government incompetence.An Angus Reid survey commissioned by the Mining Association of Canada and other mining organizations in 1989 showsthat, despite general support for its economic benefits:• 67% of the general public perceive the mining industry to be a major source of pollution and environmental contamination;• 68% believe that a new mine should not be developed if it will disturb local wildlife;• 52% would prohibit a new mine if it required a road through a national park;• 49% would disallow mine development if it took as much land as an average farm in an agricultural area or if it limited sports fishing in a local lake."

Jan 1, 1991