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By L. Cheng, Y. W. Pan, Y. R. Liu

"Impounding deformation of slope and foundation is significant during and post dam construction. Reservoir impoundment is accompanied with various phenomena, including material degradation, effective stress decreasing and buoyancy in rock masses. These phenomena are related with some engineering concerns like reservoir-induced earthquake, landslide and dam stability. The Malpasset dam and Vajont dam are typical hydraulic projects suffering from seepage in dam foundation and slope, which finally led to failure and landslide. Pore pressure in jointed rock masses is considered in constitutive relation. The expression of effective stress for porous rock with fluids is incorporated into the Drucker-Prager criterion. Based on monitoring data of valley width and dam deformation, the effective stress law is applied to analyse the impounding influence of slope and foundation to Jinping-I high arch dam. The dam is accompanied with complicated topographical and geological conditions. The results show that calculated and monitored values agree well, and the application of effective stress law provides an approach to evaluate dam deformation, stress and stability with impounding effect considered.INTRODUCTIONImpounding deformation of slope and foundation is a common and significant problem during dam construction and operation. This phenomenon exists in a lot of reservoirs in China, like Laxiwa, Ertan, Xiluodu and Jinping-I arch dams, and some dams in Europe. It is related with some engineering concerns like reservoir-induced earthquake, landslide and dam stability. The Malpasset dam and Vajont dam are typical hydraulic projects suffering from seepage in dam foundation and slope. Monitored data indicates that the valley width tends to shrink in hydraulic engineering during the impounding process, which will change the stress and deformation of dam and abutment. Therefore, global stability of dam and foundation should be evaluated with impounding process taken into consideration."

Jan 1, 2015

By Mengmeng Gai

This paper introduces a model-based automatic object recognition and registration framework to assist heavy equipment operators in rapidly perceiving 3D working environment at dynamic construction sites. A video camera and a laser scanner were utilized in this study to rapidly recognize and register dynamic target objects in a 3D space by dynamically separating target object?s point cloud data from a background scene for a quick computing process. A smart scan data updating method has been developed which only updates the dynamic target object?s point cloud data while keeping the previously scanned static work environments. Extracted target areas containing 3D point clouds were orthographically projected into a series of 2D planes with a rotation center located in the target?s vertical-middle line. Prepared 2D templates were compared to these 2D planes by extracting SURF features. Point cloud bundles of the target were recognized, and followed by the prepared CAD model?s registration to the templates. The field experimental results show that the proposed rapid workspace modeling method can significantly improve heavy construction equipment operations and automated equipment control by rapidly modeling dynamic target objects in a 3D view.

Aug 1, 2013

By A. Lam

The use of a liquid fed direct methanol fuel cell (DMFC) as a power source for micro and small portable applications is attractive due to its system simplicity, low temperature, etc. The aqueous methanol is directly oxidized and does not require additional fuel processing steps as in reformate based PEM fuel cells. In addition, the use of a liquid fuel is advantageous with respect to humidification, stack cooling and system energy density. The DMFC however, has technological issues that must be addressed before it can be widely adopted, particularly in larger applications such as small utility and transportation. At present, the crossover of methanol from the anode to the cathode is a major limitation on DMFC performance and fuel utilization efficiency. In this paper we discuss the influence of fuel modification on the control of crossover. This involves the use of different fuel additives and concentrations to minimize crossover. This appears to be the first reported case of the use of fuel modification (additives) to reduce methanol crossover. The rate of methanol permeation under passive conditions is discussed with respect to the different conditions.

Jan 1, 2005

By Pier-Olivier Devin, Daniel Hodouin, Maryam Sadeghi, COREM, Claude Bazin, François Lavoie

"Spiral concentrators are used for processing coal and heavy minerals such as it is the case for the concentration of iron oxide from light silica gangue. The concentration process for iron ore usually consists of a rougher bank of spirals followed by two stages of spiral cleaning. The process control applied to the concentration circuit aims at maintaining a target iron content of the final concentrate and is mainly conducted by adjusting the wash water addition and the position of the splitter gates at the discharge of the spiral. This paper describes the use of a simulator to study control strategies for a gravity concentration circuit using spirals.INTRODUCTION The Canadian iron ore mines are located in the Northern part of Quebec and in Labrador (Neal, 2000). These iron ores consist mainly of hematite with some ore bodies rich in magnetite and ilmenite. The processing of the coarse hematite iron ore consists of the extraction from an open pit mine, followed by the conventional crushing and autogeneous grinding of the ore to obtain a particle size smaller than 1.2 mm. The ground ore assaying 40% hematite (Fe2O3) with quartz (SiO2) as the main gangue is processed by spirals to produce an iron oxide concentrate assaying 90 to 95% hematite.Spirals separate the particles according to their specific gravity and size (Burt, 1984; Bazin et al., 2014). These environment friendly devices have been used for decades and are still used for the preparation of coal and for the concentration of heavy minerals such as iron oxide (Staff, 1977; Wills, 1992). However very little information is available concerning the control of gravity concentration circuits. This paper analyzes the control practice of a gravity concentration circuit using a simulator. The paper consists of 3 sections. The first section describes the operation of spirals and spiral concentration circuits. The second section briefly describes the simulator and shows some simulation results for a gravity concentration circuit. The third section shows the application of the simulator for the study of control strategies for a spiral concentration circuit."

Jan 1, 2016

By V. Songmene, A. Tahan, J. P. Michaud

The machining of thin wall parts, often used in the aeronautical industry still creates a number of problems, including panel deformation. Quality and productivity are often affected. This study seeks to determine the optimal conditions for cutting in order to guarantee a competitive fabrication of parts while still maintaining quality and delivery deadlines. The studied model (Spar) is a typical structural part used in the assembly of airplane wings. The main objective of this study was to improve two performance aspects: surface quality finish (quality criteria) and the rate of cutting by stock removal (economic criteria). To achieve this objective, we used an evaluation process of the geometrical error issuing from the machine-tool. We also determined the stability zones of the machine-tool's dynamic system. Finally, a series of high-speed machining tests (finishing cuts) were conducted using an experimental structured approach (16 000 - 24 000 rpm). Profile measures of surface roughness and cycle times registered during trials allowed us to establish optimal cutting conditions. Surface roughness improved as well as cutting by stock removal. Four parameters were taken into consideration: axial depth of cut, chip load, spindle speed, and cutting fluid. Finally, the influence of the type of cutting fluid was evaluated to show that it did not significantly affect machining results.

Jan 1, 2006

The SART (sulfidisation, acidification, recycle, and thickening) process is an effective way to separate copper and cyanide from each other in the waste stream of gold processing plants using cyanidation. Factorial experimentation has been conducted to create models of copper recovery, cyanide recovery, acid addition, and oxidation I reduction potential during SART. Economic analysis of the resultant models showed that SART is best operated with a sulfide to copper molar ratio of around 0.56, a pH of 4, and a minimised cyanide to copper molar ratio. The experiments also showed that thickening time may have drastic impacts on SART performance.

Jan 1, 2011

By C. Morlot, C. Auvray, E. Fourreau, J. Talandier

"During the excavation of underground galleries in a rock mass, reorganisation of the stress field around the site results in damage to the surrounding material. In the framework of research undertaken at the ANDRA underground laboratory in France, galleries have been excavated in a Callovo-Oxfordian argillite formation. The damage has manifest as a number of fracture systems in the adjacent rock. Observations have shown that fractures generated during excavation and storage exploitation are able to self-seal during re-saturation of the site in the post-closure stage. Although indirect evidence for argillite self-sealing has previously been reported, from experiments performed both in situ and on samples, no direct observations of self-sealing have yet been made.For the present study, we performed a range of self-sealing experiments using a newly-developed triaxial compression cell placed within a nano-CT scanner with a 10 µm resolution. The body of the compression cell is X-ray transparent, allowing sample healing to be monitored directly. The samples contained an artificial fracture that had been generated in the laboratory, into which a fluid was injected. The fractures were orientated either perpendicular or parallel to the plane of anisotropy of the material. Our initial results demonstrate that when fluid is injected perpendicular to the plane of anisotropy, the flow-rate has no apparent influence on the kinetics of fracture closure. Permeability varies significantly, from 2.10-14 to 2.10-18 m2 over 116 hours. Post-test observations of the fracture lips show swelling that appears to be orientated perpendicular to the fracture plane and therefore parallel to the plane of anisotropy. Initial results for an injection parallel to the plane of anisotropy suggest that, in this case, the rate of flow affects the kinetics of fracture closure. For a flow-rate of 0.25 ml/min, closure begins after around one minute. In contrast, for a rate of 0.05 ml/min, it is necessary to wait several minutes before partial sealing of the zone is observed. The reduction in permeability is again significant, from 2.10-15 to 4.10-18 m2 over 96 hours. After completion of the test, swelling was observed in elongated zones that lie parallel to the fracture plane and therefore to the plane of anisotropy."

Jan 1, 2015

By Zhen Lei

In Alberta, Canada, heavy industrial projects are constructed using a prefabrication approach: spools and pipes are produced in the factory, and are assembled into modules that are transported to the industrial plants for installation by mobile cranes. Planning the onsite mobile crane operations is critical to the project budget and schedule. However, due to the large magnitude of industrial projects, manual heavy lift planning is tedious, and the results are not particularly responsive to site changes. This paper introduces an integrated mobile crane management system developed by PCL Industrial Management Inc., in collaboration with the University of Alberta, which investigates crane location selection and path checking for field module assembly. The project information is stored in a database, and the proposed system retrieves data, performs the calculations, and records the results back to the database; the calculations involve automatically selecting locations for the mobile crane, considering the crane capacity, lifting range and utilization. Lift paths for modules are checked for feasibility based on selected locations, satisfying the site and crane configuration constraints, and crane walking paths are planned if needed. The designed system is tested in an industrial project to validate the effectiveness of the system.

Aug 1, 2013

By Alfred E. Pugsley

PAYMASTER CONSOLIDATED MINES, LIMITED, began an investigation into the economy and use of detachable bit drill-steel in June, 1937. This investigation has continued to the present time, and was made necessary by transportation and distribution difficulties that had arisen through the use of standard steel in three widely separated mine areas serviced by a central steel-sharpening shop. Detachable bit drill-steel performance was first studied in the workings of No. 2 mine, where the rock being drilled was composed mainly of porphyry or tourmaline, and where standard drill-steel transportation costs had been excessive. The results obtained in this early work definitely established the economy of detachable bit drill-steel at No. 2 mine. This conclusion was reached when the 're-grind' system of re-sharpening dulled detachable bits was 1n use. Preliminary observations on the performance of detachable bit drill-steel in the quartz-carbonate veins of No. S and No. 6 mines gave encouraging results, and warranted a large-scale investigation under practical mining conditions. All drilling operations were gradually changed over to use of detachable bit drill-steel. This change was completed by February, 1938.

Jan 1, 1939

By S. K. Sharma, Sanket Bacchuwar, Prabal Kumar Agrwal, G. V. Rao

"Iron ore processing industries play a vital role in the Indian economy. At present Iron ore of around +64% Fe is used for production of Iron through blast furnace. To produce +64% Fe from low/medium grade ores, crushing & beneficiation is compulsory. But during these processes, large amount of slime is generated. It is estimated that 18% -25% of tailing is generated during the processing of iron ore. The iron ore slime is discarded because of its particle size and chemical composition not being suitable as feed to the blast furnace. Although the fines/slimes can be agglomerated to larger particle, the alumina to silica ratio which is normally more than one pose serious problem during sintering process and subsequent smelting in blast furnace. The alumina content in the slime needs to be reduced for it to be used as the feed for blast furnace. The sample assayed 61.40% Fe, 7.68% SiO2, and 1.52% Al2O3, LOI 2.63% and all other elements were found in critical limit. A series of 27 tests were conducted by using a spiral for optimisation of process parameters to produce a pellet grade concentrate from the stacked slimes obtained from Kirandul. This paper deals with the optimisation studies of various parameters of a spiral concentrator and helps to utilize the fines from tailing ponds.INTRODUCTIONReserves of high-grade iron ores are diminishing all over the world at an alarming rate. As a result, alternative ways of augmenting and conserving precious and non - renewable natural resources are being seriously considered. One such attractive option is the recovery of metal values from slimes / tailings. Iron ore tailings containing around 48 - 60% Fe are generated from the iron ore washing plants and are disposed into tailing ponds without any further utility. These tailings in the form of slimes are not suitable in iron and steel making due to the presence of higher amount of gangue constituents. Several beneficiation techniques have been tried from time to time to reduce the gangue so that the beneficiated products could be effectively used."

Jan 1, 2016

By Rita Michael

"The Marmara Ironworks was not the earliest ironworks in Ontario, but it was distinguished from other early works in a number of ways. It was established on an ambitious scale as a self-sufficient and, for the time, sophisticated community. In effect it was an iron plantation on the scale and scope of those at Hopewell, Pennsylvania and Saugus, Massachusetts(1). It was, besides, the only one of the few early ironworks in Upper Canada which operated almost to the end of the nineteenth century, albeit in fits and starts, and which used magnetic ores rather than bog iron ores (limonite). Furthermore it is the only works which has produced archaeological interest over a number of years. The ironworks is on the east bank of the Crowe River near Highway 7, on Lots 7 and 8, Concession 4, Marmara Township, Hastings County, Ontario. It is the property of the Village of Marmara, and the extant remains encompass about 2. 5 acres of the original 2000 or so which made up the original grant. The mineral riches of the Canadian Shield had been known since the days of the Jesuit missionary-explorers. A consortium headed by Alexander Henry and the Duke of Gloucester planned to exploit the copper near Sault Ste. Marie during the last part of the eighteenth century, but nothing came of the venture(2). This attempt may have grown out of Lord Dorchester's suggestion that private enterprise be encouraged in order that the iron ore which ""abounds"" in Canada might be exploited(3). John Graves Simcoe, the first Lieutenant Governor of Upper Canada was also anxious to see iron working develop. Simcoe was eager to encourage many enterprises, among which ""the development of iron mines""(4) - Governor Gore had been approached by John Mason for help with his ironworks in Norfolk County (5). Three Americans had applied for permission and support to erect an ironworks on the Gananoque River at the falls to become known as Furnace Falls. They were granted 1000 acres of land in fee simple to encourage their endeavor(6). Sir Peregrine Maitland, only a few months after taking up his duties as Lieutenant Governor in 1818, intended to visit the ""bed of iron ore on the Crow River"" (7) - Maitland was to provide a good deal of support, both moral and substantive, to Charles Hayes when he came to Canada in 1820."

Jan 1, 1999

By J. E. Nesset, W. Zhang, J. A. Finch

Frother influences water recovery through control of bubble size and a chemical effect. De-coupling the two is necessary to establish the extent of the chemistry effect. A setup is described to give steady state water overflow rate (Jwo) along with measurements of bubble size into and on top of the froth. Arguing neither bubble size correlates directly with water overflow, a frother mass balance is solved to estimate the bubble surface area flux in the overflow (Sb0 ). The solution required measurement of frother concentration using TOC analysis and frother adsorption density using surface tension data. The relationship between Jwo and Sbo reveals the frother chemistry effect, quantified for discussion purposes by an equivalent water layer thickness.

Jan 1, 2009

By G. Deschênes

"In 2013, as the prices of precious metals dropped, investors moved their positions to equity markets for higher returns. As a result, the price of gold dropped further to below US$1200 per ounce, prompting additional substantial outflows from gold investments. In response to lagging gold prices, major gold producers initiated large asset write-downs and cost-cutting programmes. In 2015, this trend continues and gold mining stocks are close to lows not seen since the global financial crisis (GFC) of 2008. In the current economic climate many projects have marginal economics, and the number of projects that have competitive development and production costs is declining. A competitive edge is particularly important with the decreasing grades of orebodies, increasing complexity of the mineralogy, and increasingly demanding environmental constraints. In addition, higher cost producers seek to optimize their process t o reduce operating costs.This paper presents some highlights of three case studies on optimization of gold leaching strategies that improved the economics of brownfield projects. Processing of sulphide-bearing ores was optimized by using the synergy between cyanide, lead nitrate, and oxygen. The outcomes were significant reduction of retention times while maintaining or increasing gold extraction and reducing cyanide addition and effluent treatment costs. A stirred tank reactor experimental programme led to direct implementation of reliable leaching strategies from laboratory scale to production. This approach resulted in savings of $2.2 million to $15.2 million on the three brownfield projects discussed in this paper."

Jan 1, 2016

By K. Hanumantha Rao, A. Javadi

Our recent studies revealed that the sulfide minerals in contact with water during grinding produced hydrogen peroxide (H2O2) where the amount of H2O2 production by the minerals found to be in the order of pyrite > chalcopyrite > sphalerite > galena. The H2O2 effect on the oxidation of pulp components and its influence on the concentrate grade and recovery in flotation have been studied and the results have been presented and discussed in this paper. Studies have also been carried out to build correlation between percentage of pyrite in the concentrate, grinding conditions and concentration of OH•/H2O2 in the pulp and as well of controlling the formation of these species through known chemical means for depressing the generation of the oxidant. Flotation tests using a complex sulfide ore with the same reagent scheme that is being used at Boliden concentrator in Sweden but with the addition of i) collector and depressant, ii) Na2S reductant and iii) inorganic (EDTA) and organic (TETA) surface modifiers, during grinding stage have been performed to judge the beneficial or detrimental role of H2O2 on the selective flotation of sulfides. The results demonstrate that the selectivity of metal sulfides against pyrite increases with increasing generation of H2O2 in the pulp liquid. H2O2 is also found to be a better oxidant in chalcopyrite-galena flotation separation than the commonly used K2Cr2O7.

Jan 1, 2016

By K. D. Peaslee

Slag splashing is an important development that has dramatically improved BOF vessel campaign life and reduced operating costs. This paper highlights research from physical modeling work using a 1/8-scale room temperature model BOF and slag characterization studies from several plants in North America and China. In the model studies, gas flow rate during blow and viscosity of the liquid were found to be two of the most important factors to changing the overall rate of liquid splashed onto the vessel sidewalls. When the flow rate was increased or viscosity decreased, the lower regions of the walls were splashed at a much greater rate. It was also shown that by changing the lance height, more liquid was deposited in the upper regions of the vessel at the expense of lower regions. Reducing the number of nozzles was found to be the most effective method of selectively coating a particular vertical section of the wall. Studies of BOF's using slag splashing in North America and China showed a difference in the melting characteristics of the final slag. Generally, slag splashing is successful when the melting point of the slag is 220-270°C below the tap temperature to maintain a balance between fluidity and refractoriness.

Jan 1, 2004

By Timothy W. Ellis, Abbas H. Mirza, R. David Prengaman

Recycled lead, i.e. material produced by the recycling of lead-acid batteries, has become the primary source of lead in much of the world. This has been important to the recycled lead industry as other uses have dwindled, e.g. lead based pigments, chemicals, fuel additives, solders and CRT glasses. Presently, battery manufacturing accounts for greater than 85% of lead consumption worldwide while recycled lead accounts for approximately the same market share of lead supply. Battery manufacturing and production of recycled lead are intimately coupled. In 2007, of all the industrial base metals, lead from lead-acid batteries had the highest recycling rate in North America at greater than 95%. In this paper we will review some of the processes and technologies used in a modern lead acid battery recycling facility, and how recycled lead has become the material of choice for battery construction through the development of a recovery and refining process that exceeds the industry requirements. We will also briefly review an advanced air emissions treatment system in a modern lead recycling plant that demonstrates the feasibility of a new maximum available control technology (MACT) for secondary lead smelters.

Jan 1, 2011

By \/eena Sahajwalla, Alexander Blagus

This paper reports the effect of using High Density Poly-Ethylene (HDPE)/coke blends on the reduction behaviour of Mn3O4 to MnO at 1000°C. The results suggest that CH4 release increases with increasing HDPE addition. The results show that the rapid release of methane, over only the initial five minutes, limited the interaction of Mn3O4/MnO with CH4. With the devolatilisation of HDPE there was increased porosity in samples containing HDPE, assumed to be the major factor in differences of reduction rates.

Jan 1, 2011

By H. Hamza

Efficient and effective management of extraction process tailings is an essential ingredient for the continued success and development of Alberta's vast oil sands resources. Open-pit oil sands operations north of Fort McMurray recover bitumen from flotation circuits. Process tailings are managed in carefully engineered and monitored external tailings management facilities and in below-grade mine pits. In order to support reduction of production costs and improve upon established tailings management practices, CANMET has been working with the oil sands industry in a collaborative framework to assess the potential to integrate thickened tailings into oil sands extraction process flowsheets. Albian Sands has commercialized the process while others, including Syncrude Canada Ltd., continue to evaluate the suitability of the process for their operations. This paper provides an update on R&D work undertaken in recent years to assess and develop the potential of thickened tailings technology for the open-pit oil sands operators of northern Alberta. The aim of this work was to explore opportunities to optimize process efficiency and environmental sustainability by improving water and energy conservation and develop more alternatives for tailings management and reclamation.

Jan 1, 2004

By W. S. Dyer

Introduction In northern Ontario, refractory clay is found on four rivers of the James Bay watershed: the Abitibi, the Mattagami, the Missinaibi, and the Moose. The clay all belongs to the same geological formation ( the Mattagami of Lower Cretaceous age) , and occurs within a structural depression or 'basin', the boundaries of which have never been defined but which appears to cover at least 1,500 square miles of territory. The recently constructed James Bay extension of the Temiskaming and Northern Ontario railway crosses the northeast end of the basin at the Onakawana lignite field, which by rail is 126 miles north of Cochrane, 605 miles north of Toronto, and 60 miles southwest of Moose Factory. Smoky Falls, the northern terminus of the railway owned by the Spruce Falls Power & Paper Company, Limited, is 7 miles south of one other point in the basin, i.e., the outcrops of refractory clay, sand, and kaolin at the foot of Long rapids on the Mattagami river. Smoky Falls is 50 miles north of Kapuskasing. In a very early report(l) , Dr. Robert Bell, of the Geological Survey of Canada, described '"light coloured marl in horizontal beds" from the Missinaibi river, and noted that the lignite also occurring in the river was probably :associated with the marls. This was undoubtedly the Cretaceous refractory day. Other early writers noted the occurrence of fire-clays, but it was not until Joseph Keele(2), of the Geological Survey, visited thee region in 1919 and studied the clays that their real significance was known.

Jan 1, 1933

By Hong Zhong, Shuai Wang, Fangxu Li, Guangyi Liu

"The flotation performances and adsorption mechanisms of a-hydroxyoctyl phosphinic acid (HPA) to malachite, cassiterite and wolframite were investigated by micro-flotation tests and X-ray photoelectron spectroscopy (XPS) analyses. The micro-flotation results indicated that compared with styrene phosphonic acid (SPA), diphosphonic acid (DPA), benzohydroxamic acid (BHA) and salicylhydroxamic acid (SHA), HPA exhibited excellent collecting power to the three oxide ores. In addition, HPA showed superior selectivity against hematite, tourmaline, feldspar and quartz. The results of XPS analysis demonstrated that HPA reacts with active species (M) on metal oxide by formation of P-O-M or P-M bonds.INTRODUCTIONIn mineral processing, flotation has been the main process for separation and recovery of valuable minerals from complex ores (Mei, 2013; Zhou, 2014). One of the key requirements in flotation process is to increase selectively the surface hydrophobicity of the targeted minerals by surfactant (known as collector in flotation) adsorption so that these mineral particles can preferably attach air bubbles in a slurry or pulp (Bai, 2004; Hankins, 2004). To anchor a solid surface selectively, special functional group are designed to adjust the interaction between the surfactant and the active sites of solid surfaces (Wu, 2006; Huang, 2014).Organic phosphorous compounds have strong affinity toward metals or metal oxides because they form more stable metal complexes than metal carboxylates (Pazik, 2001; Zheng, 1998). In mineral engineering, phosphorous compounds have been exploited as metal extractants and flotation collectors (Alguacil, 2002; Sun, 2008). Ni (2012) and Zhang (1998) introduced diphosphonic acid (DPA) as an effective collector for flotation of fersmite and niobite. Liu (1999) found styryl phosphonic acid (SPA) was a superior collector for flotation recovery of finely disseminated rutile ores. Gruner and Bilsing (1992) thought SPA was one of the best collectors for flotation recovery of cassiterite which could obtain a high-grade concentrates of more than 40% with high recovery values. Bulatovic (1999) investigated the flotation performances of phosphoric acid ester (PAE) to perovskite, ilmenite and rutile and found that PAE was an impactful collector for selective flotation of titanium minerals from complex ores in the presence of petroleum sulfate. However, a-hydroxyoctyl phosphinic acid (HPA) as a flotation collector for recovery of titanium ores were hardly reported in the previous literatures."

Jan 1, 2016