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By F. Fournier Dit Chabert, F. Tancret, J. François Castagné, R. Le Gall

During the repair of turbine blades by a laser cladding process, it is observed that interdendritic cracking occurs in the heat affected zone (HAZ). Auger electron spectroscopy, performed on sample broken at high temperature, reveals interfacial sulfur segregation, which is known to be one of the main causes of microcraking in the HAZ during welding processes. Moreover, thermal gradients generated by the process are responsible for important thermomechanical stresses. In the present work, the finite element code Comsol Multiphysics is used to simulate the laser cladding process in order to determine both the thermal field and, using an elastoplastic law, the stress field inside the component. The originality is that the temperature history calculated in the thermomechanical model is extracted then injected in a segregation model in order to calculate the local segregation behavior. This model can be eventually used to predict the risk of cracking as a function of process parameters and alloy chemistry.

Jan 1, 2006

By Luis R. Fonseca, C. Raimat, C. Wendeler, A. Sanz

"Rockfall barriers are widely known as proven efficiency element to protect infrastructure by catching the rock blocks in the falling direction and absorbing the energy generated by them.It’s common in the project design phase and during installation, fix rockfall barriers for catch a high percentage of the falling blocks and in many cases consider as valid the solution when the barrier can capture all of them. However, in many cases it’s possible to consider the use of these protections, simply to guarantee a secure shed for the traffic and intercept simply the blocks that theoretically hit the road surface.The results of the high-energy rockfall protection barriers type GBE which protect GC-200 road in Las Palmas de Gran Canaria are shown in this paper.The topographic data should be especially detailed observed and even more if you want to apply the technique of ""shadow zone"" with a flexible gallery system. It should be drawn from detailed topographic maps and drawings (photogrammetric restitution) to the scales 1/1000, 1/500, or 1/200; and it is important not to ignore the presence of vertical cuts, tracks, small slopes that modify the trajectories (trampoline effect, hard points that favor the rebounds) and which are not always presented in the drawings.The ""shadow zone"" is defined as the protected area, located at a lower elevation to the line created by the rockfall barrier to except of trajectories of rocks and free from the influence of the deflection of the system under the maximum energy level for which it was designed (MEL)."

Jan 1, 2015

By A. Anderko, R. D. Springer, R. D. Young

A thermodynamic model has been developed for calculating phase equilibria and other properties of multicomponent electrolyte systems. The model has been designed to reproduce the properties of both aqueous and mixed-solvent electrolyte systems ranging from infinite dilution to solid saturation or pure solute limit. The model incorporates formulations for the excess Gibbs energy and standard-state properties coupled with an algorithm for detailed speciation calculations. The excess Gibbs energy model consists of a long-range interaction contribution represented by the Pitzer-Debye-Hiickel expression, a second virial coefficient-type term for specific ionic interactions and a short-range interaction term expressed by the UNIQUAC equation. The accuracy of the model has been demonstrated for common acids and bases and for multicomponent systems containing aluminum species in various environments.

Jan 1, 2005

By C. M. Bartley

Fluorspar, in addition to its familiar uses as a metallurgical flux and as a source of the electrolyte for aluminum production, has become important as an essential raw material in the rapidly growing fluorine chemical industry. The unique ability of fluorine to react and form compounds with al-most all other chemicals has made it one of the important elements in modern chemistry. Research and development over the past thirty years have resulted in a current annual production of fluorine chemicals that is both technically and economically important to industry. Because many of these chemicals and products are relatively new, and most have properties that are not duplicated by other materials, the present uses are expanding rapidly and new applications are being reported continually. Fluorspar, the only immediate and practical source of fluorine, is therefore an important mineral. This fact has been recognized in major industrial areas such as the United States and Western Europe, but has received little attention in Canada.

Jan 1, 1962

By John Galbraith, Dwayne D. Tannant, Chris C. Langille

"Development of underground openings in a deep mining environment requires a support system that is able to absorb energy as a result of dynamic loading due to rockbursting and blasting and static loading due to convergence as the development face advances. The support system must be resistant to corrosion and be effective over the life of the excavation, upward of ten years, yet simple and cost effective to install. Over the past two years, research has been conducted at INCO’s Creighton Mine to try and identify a one-pass grouted support system that will meet these needs.The main problem faced, with simply using grouted rebar at depth, is the effect of tunnel convergence on the stiff grouted bolts. Typically, if fully grouted, stiff rebar are installed to the face of an advancing development heading, the amount of convergence that occurs can result in failure of the bolts at the face plates used to attach the mine screen to the back. An initial support is required to enable crews to continue the bolting cycle in the immediate term, yet allow for this convergence over the longer term as the drift advances. The ideal support system will allow both to occur, giving effective immediate support while providing long-term effectiveness in allowing convergence to occur while maintaining the capacity of the bolt.This paper will investigate the expected convergence in deep development headings at +2200 m (+7200 ft) through the use of direct measurements using both flex rod extensometers grouted into the back of a development heading and five-point tape extensometer stations. Measured results will be compared with simple2-D numerical analysis to evaluate the anticipated convergence expected to be absorbed by the bolting system. The required convergence will then be compared with load deformation response of several support configurations."

Jan 1, 1996

By Bennett McLaughlin

AGNICO-EAGLE started sinking the Penna Shaft in 1995 with a hoisting plant capable of hoisting 1,800 tonnes per day from a 2,240 metre deep shaft. Exploration success lead to the installation of a hoisting plant capable of extracting 4,500 tonnes of ore and 1,800 tonnes of waste per day from a depth of 2,210 metres. The introduction of a new rope selection factor, permitting a safety factor of 4.0, represented the breakthrough required for a cost-effective project. This paper describes the process taken to introduce the new rope selection factor and its impact on the original plant.

May 1, 2001

By J. R. MacDonald

MINING literature contains very few descriptions of operations producing as little as 25 to 30 tons of ore per day. The purpose of this paper is to discuss the gradual development of a mining method for such a small-scale operation at the No. 2 mine of Central Patricia Gold Mines, Limited, and in doing so to review several systems of stoping applicable to narrow ve1ns. MAIN ECONOMIC FACTORS TO BE CONSIDERED (1) Overhead.-The outstanding feature of most mines operating on a single narrow vein is chat of small daily tonnage. The reason for this low output can be readily understood. The strictly limited ore-reserves present a condition unfavourable for a policy of large initial expenditures, with the result that the capacity of the plant provided must be governed by the? amount of ore in sight at the time when mill construction is planned. This is immediately reflected in the cost per ton, there being relatively few tons over which to distributed the more or less static charges, such as hoisting, heating, supervision, administration, pre-production expenses, and other write-offs. (2) Development.-In mining this type of orebody, the main factor contributing to high costs is unquestionably the small tonnage of ore made available by a given amount of development. Thus, for example, from the data tabulated below it can be seen chat, assuming a 12-in. vein and a drifting cost of $9.00 per foot, the development charge for this item alone would be 71 cents per ton. Add to this the charges for raising, cross-cutting, shaft-sinking, and pumping, besides charges arising from development in waste, and the figure will be very considerably higher than 71 cents.

Jan 1, 1941

By R. A. Campbell, R. R. Rogers

"AbstractThe experiments described show that crude bismuth metal containing up to 5 per •cent lead, 0.14 per cent silver, 0.015 per cent copper, 0.02 per cent iron, .and small amounts of antimony, nickel, and tin may be refined to a bismuth content of 99.98 per cent by distillation followed by chlorination. It also is shown that bismuth trichloride of high ,purity may be produced by passing chlorine over hot •crude bismuth metal and allowing the resulting vapours to •condense in a cooler .part of the system.IntroductionBISMUTH is used in the production of alloys and pharmaceuticals. During 1952, the New York price for the refined metal was $2.25 per pound in ton lots.Some months-ago a Canadian producer requested the Mines Branch to investigate methods of refining the bismuth which they had been producing. Their crude product had been selling for $1.50 to $1.70 per pound and it was desired to increase its purity to at least 99.98 per cent so that it could be sold for $2.25 per pound."

Jan 1, 1955

By P. Patnaik, F. Cuneo, D. M. Wang

Microwave (MW) energy has been used widely for several decades for communications, food processing, wood drying, vulcanization of rubber and medical therapy. Recently, this technology was found to be capable of successfully sintering ceramic and metallic powder materials, with the advantages of reducing soaking times and sintering temperatures. Unlike conventional heating, MW radiation works through the absorption of the microwave energy by a material placed in an electromagnetic field within the microwave cavity. A far more efficient heating process is produced due to the unique ability of microwaves in selectively heating a pecific part of the material with desirable dielectrical properties. This exploratory research was initiated with the objective of locally sintering the thermal barrier coating of gas turbine components using MW radiation. This novel technique may allow repairing of the component without subjecting the entire piece to unnecessary elevated temperatures and reduction of process time and cost. Y ttria stabilized zirconia was used in this study and sintering was conducted using a multimodal 1.2 kW microwave facility. Three configurations of heating setup were experimented and the preliminary results will be discussed in this paper.

Jan 1, 2006

By Mohammadreza Jalali

Alberta contains over 400 billion barrels of viscous crude oil in fractured carbonates but there is no viable extraction technology as yet. Petroleum geomechanics has become a vital part of the assessment of such hydrocarbon reserves, especially for naturally fractured cases, which are particularly challenging in terms of accurate recovery prediction because of joint fabric complexity and lithological heterogeneity. As a result of interconnected fractures, transport properties of fractures (mostly permeability issues rather than thermal effects) are affected by production and injection activities that change the pore pressures, temperatures, saturations, and effective stresses. Enhanced oil recovery methods involving massive amounts of fluid injection (hot or cold) at high pressure (pinj) may be used to mobilize and produce the oil; therefore, deeper understanding of the fractured systems is desirable. Pressure and temperature variations in a fractured reservoir change the in situ stresses in the reservoir and surrounding rocks; this affects fracture apertures, radically changing the bulk flow properties because flux rate is highly sensitive to aperture. Hence, coupled pressure, temperature and effective stress changes must be considered for fractured reservoirs under a thermo-hydro-mechanical (THM) coupling approach.A hybrid FDM/DDM coupled method is presented to couple pore pressure and stress around a fracture in an impermeable matrix block. Deformation and stresses are calculated in each time step and then fracture permeability, which is the most sensitive petrophysical parameter in fractured reservoirs, is updated based on the fracture aperture variation. This model is then verified with UDEC (Universal Distinct Element Code) which uses a discrete approach to cope with fractured rock mass behavior.

Jun 1, 2012

By W. H. Hodgson, A. R. Preston

"Improved rail production techniques provide new options for the rail user. Steelmaking improvements offer tighter composition control, lower oxide and sulphide counts, greater control of segregates and freedom from hydrogen problem s. New ultrasonic, laser and eddy current equipment gives printout information on surf ace flatness, straightness and internal condition. These have come along at a time when dramatic changes have occurred on the rail heat treatment scene. Rails can now be deep hardened on or offline in ways which should eventually result in a complete rewrite of the world's specifications. Rails of simple composition can be produced in the hardness range 2801400 BHN as required. The rail user can choose the hardness within this range according to requirement without the necessity for any step changes in the process routes.It is suggested that this is the pattern f or the next decade.IntroductionRails have been the subject of very slow improvement over many years but developments gathered momentum in the early seventies. Recent improvements in quality and properties have provided dramatic increases in rail life under the more severe service situations. Rail profile grinding, lubrication and other track improvements have greatly added to expectations of even longer life. All of this, coupled to even newer mill heat treatment developments, tilt both technical and economic advantages away from tradition to the point where specifications will need to be rewritten so that railroads can take full advantage of these new products."

Jan 1, 1988

By Mohamad Kharseh

There is general acceptance that climate change, which is the most important challenge facing humanity, is anthropogenic and attributed to fossil fuel consumption. Therefore, improving the performance of our existing energy systems and deploy more renewable energy resources is an urgent issue to be addressed. Geothermal refers to existing of heat energy in deep rock and sedimentary basins. This energy can be used to drive a power turbine to generate electricity. Traditionally, geothermal has been exploited in places with the plentiful hot water at relatively shallow depth. In the light of fact that ground temperature increases with the depth everywhere on the Earth, engineered geothermal systems (EGS) can be installed in any place to exploit the geothermal in generating energy. Unfortunately, the high exploration and drilling costs of boreholes is the main barrier to commerciality of EGS worldwide. In addition, there are technical problems associated with drilling big depth. In oil producing countries such problems can be addressed by utilizing whether active or abandoned oil or gas wells and, consequently, EGS can produce power at profit. The current study presents an analysis of a binary geothermal power generation system for commercial electricity generation in Qatar. For this purpose, two binary cycles are assumed the main difference between them is that the first one is air cooled while the other will be water cooled. The performance of the two cycles and the possibility of improvement has been shown. Economic analysis the power plant shows that the levelized costs of electricity is 3.6US¢/kWh and the pay-back time is less than 8 years.

Aug 1, 2013

By S. W. Marcuson

In the late 1960's concerns about the natural environment reached high levels within North America and provided activists with suitable platforms for exerting influence over the general public and politicians. In response a host of regulatory mechanisms were developed, statutes, voluntary measures, land grants, codes of practices etc. Emerging environmental awareness from the era provided impetus for rapid technological change that encompassed all industries, especially the base metal business. The resulting clean up impacted all aspects of copper production, dealing with issues such as waste disposal, water and air quality with specific impact on emissions of sulfur dioxide and particulate. This paper provides a perspective of these changes reviewing the macro-economic impact of environmental movement in mining with its specific implications to the copper smelting industry. The fundamental challenges that were faced by the old, but capital-intensive North American plants and the approaches taken to deal with the changing times are reviewed with special emphasis on the conceptual approach to smelter S02 abatement and different paths taken in the USA and Canada. The role of economics, sustainable R&D and presence of technical infrastructure that facilitated the change process is elucidated, and speculations are made about the future state of pyrometallurgy and the natural environment. Cu2007 -

Jan 1, 2007

"An innovative concept is proposed whereby the operating power for haul trucks in certain areas of an underground mine are reduced in order to lower ventilation costs. Airflow that must be provided for diesel-powered equipment in most jurisdictions are regulated based on engine peak power capability and engine emissions, both of which can be lowered by artificially reducing the capacity of the engine through the engine control unit. Advances in asset tracking and ventilation on demand enable this methodology and this study demonstrates that it could represent significant value for mine operators. An examination of haul truck duty cycle indicates that de-rating of engine operating power based on the truck’s location in the mine can enable a step change in ventilation rates, often with no material impact on working conditions. Methods for implementation and estimate of cost savings will be defined.INTRODUCTION Ventilation of underground workings remains a significant operating cost burden for modern mine operators. In particular, ventilation rates for underground diesel mining equipment are often defined by local regulatory bodies and are assumed to present minimal opportunity for optimization or savings, at least until battery propulsion systems can be adopted. Commonly, the quantity of air flow required is defined by the peak rated engine output power of diesel equipment. For example, Ontario Regulation 854 SS 183.1 (3) states that “The flow of air must be at least 0.06 cubic metres per second for each kilowatt of power of the diesel-powered equipment operating in the workplace”. Jurisdictions that define air flow using the prescribed CANMET or MSHA ratings use peak engine emissions to calculate air flow required for dilution ventilation. These approaches are similar in that the maximum power capability of a vehicle’s engine is used to define the ventilation rate in all areas where it travels, regardless of what power output is actually used in any of those areas. Examination of the duty cycle of a typical underground haul truck identifies a large variance in the power output of the vehicle depending on its location in the mine and the activities undertaken at these locations. For example, travel on a mining sub-level requires a fraction of the truck’s peak power due to the minimal grade and significantly reduced travel speed. So if we can reliably reduce the peak engine power capacity and engine emissions in areas where peak power is not required, we can logically cut the ventilation rates for those areas."

Jan 1, 2017

By A. L. Mackie

Mine water from base metal mines is generally characterized as having high concentrations of heavy metals and low pH, resulting in the need for treatment prior to discharge to receiving waters. In this study, two high-rate clarification processes were evaluated at bench-scale: the high density sludge (HDS) process and sand-ballasted flocculation. High-rate clarification processes generate larger, denser flocs which settle more quickly than those formed in conventional flocculation processes. The HDS process uses recirculated sludge in order to seed floc formation, whereas ballasted flocculation uses microsand. Both of these high-rate processes require the addition of quicklime or hydrated lime to increase pH and allow for the formation of insoluble metal hydroxides, which can then be removed in the clarification stage. Previous research has shown that cement kiln dust (CKD) can effectively replace quicklime in conventional sedimentation processes for metals and acidity reduction to meet discharge guidelines (Mackie & Walsh 2012). CKD is an alkaline by-product of cement manufacture that has fine particle sizes and varying free lime concentrations depending on the manufacturing process. The lower solubility (i.e., free lime content) of CKD requires larger doses of material to be added to reach treatment pH targets for metals precipitation. The purpose of this study was to evaluate the treatment efficacy of high-rate clarification processes for mine water treatment, compared with conventional sedimentation, at bench-scale with conventional (i.e., lime) and novel (i.e., CKD) pH adjustment additives. Results of the study showed that all treatment processes (i.e., HDS, ballasted flocculation, and conventional sedimentation) were able to reduce target metal concentrations to well below Canadian guidelines (i.e., total zinc and total nickel < 0.5 mg/L, total copper < 0.3 mg/L) using either CKD or lime. Additionally, mine water samples treated with CKD generated lower sludge volumes than those treated with lime (i.e., 50 versus 100 mL for conventional sedimentation and 100 versus 200 mL for HDS) even with increased concentrations of solids introduced during treatment. This is most likely due to slower neutralization rates when using CKD, due to its lower solubility, as well as finer particle size. The sand-ballasted flocculation process was able to reduce final turbidity in CKD-treated samples while the HDS process did not when compared to conventional sedimentation, making the ballasted flocculation process preferable for reducing final solids concentrations in CKD-treated mine water.

Aug 1, 2013

By G. Frithum

In the present paper a new and highly economic route for Fe-separation from HCl leaching processes in hydrometallurgical applications is described. In most ore leaching processes, Fe is involved and needs to be separated; HCl has become an interesting leaching agent, because it can be recycled. Usually a mix of Fe2+ and Fe3+ is obtained which can be hydrolyzed directly (in case only Fe3+) or roasted via pyrohydrolysis (in case of Fe2+) to ferric oxide. Economic oxidation of Fe2+ to Fe3+ is described, and potential technologies for regeneration of HCl with separation of Fe are shown and compared.

Jan 1, 2014

By E. A. Morris

It has been shown that Alberta oil-sands fluid coke can be effectively used to reduce SO2 to elemental sulphur while simultaneously producing sulphur-impregnated activated carbon (SlAC). In the capture of mercury from industrial flue gases, SIAC has proven to be a highly effective adsorbent material. The current research aims at developing an existing SlAC technology to meet the needs of copper smelters for mitigating both mercury and SO2 emissions, while making elemental sulphur as a co-product. The challenge behind this undertaking is that these flue gases generally contain percent levels of 02 and H20 vapour (2-12%). The focus of this study is therefore on the feasibility of reducing SO2 using fluid coke under copper smelter flue gas conditions, as well as the optimisation of SIAC properties for capturing vapour phase mercury. It is hypothesised that mercury capacity is strongly affected by the 02 potential of the activation gas due to changes in surface sulphur types arising from different reduced sulphur species. To verify this, gas chromatography is used to analyse the reaction products while XPS and XANES will be used to describe the nature of sulphur on the SlAC surface. CVAFS analysis of mercury capacity will finalise the hypothesis assessment. Preliminary results indicate that 02 at 5% does not play a significant role in SSA or pore development. As expected, increased residence time contributes to SO2 reduction and elemental S yield.

Jan 1, 2007

By L. Becze, B. Pierre, S. Di Carlo, G. P. Demopoulos

From January to June 2007, the autoclave production at the Kidd Metallurgical Site was severely affected as a result of plugged discharge lines and extensive precipitation/crystallization of sulphates that caused massive scaling in different autoclave compartments. Work was performed at McGill University to understand the root causes. The crystallization of zinc and ferrous sulphate salts was investigated in terms of solubility measurements. Scale samples were characterized using chemical and mineralogical-spectroscopic analysis. In this paper, following a description of the Kidd zinc pressure leach operation, highlights from this investigation are presented and solutions used to overcome the problem are outlined.

Jan 1, 2008

By Fabio Mielli

In these times of increasing costs and diminished returns, energy consumption is one source of savings that remains relatively untapped in the mining sector. Typically, 15% to 40% of operational costs can be attributed to energy in mining operations. This ?process variable? is a complex, multi-faceted variable that involves government regulations, societal pressures, cost and competitiveness. A mining company able to successfully embrace an energy efficiency program is more often than not a successful mining company. Production optimization programs, relatively common today, provide increased production, increased availability of assets and, in many cases, improved quality. They generally ignore the energy question altogether. Production Energy Optimization combines reductions in energy consumption with production improvements to reduce the cost per unit of production while improving emissions reporting. An energy strategy in mining and mineral processing operations is a critical component of Production Energy Optimization. This strategy must support the financial and operational integrity of the business. Developing a successful energy strategy requires a well structured approach such as following: ??Understanding where energy is being used and why, ??Recommending and implementing energy conservation measures, ??Driving visibility to targets and results, ??Re-evaluating continuously. The objective of this paper is to help you better understand the process, tools and technologies that enable mining organizations today to address energy and sustainability issues more tactically and proactively.

Aug 1, 2013

By R. M. Kleine

In the fall of 1968, Sheridan Geophysics leased the Renzy Mine property 50 miles northwest of the town of Maniwaki, Quebec. A 500-tpd flotation mill was dismantled at Belleterre, Quebec, trucked into the mine over a winter road and re-erected during extreme winter conditions. Approximately one billion gallons of water were removed from Renzy lake to expose the orebody. A 3,000-hp diesel generating plant and a self-supporting community were set up during the early part of 1969. This was a remark-able achievement considering that most of the work, including the pouring of foundations and the draining of the lake, had to be done during the winter months. Despite this, the project was completed ahead of schedule and one million dollars below budget. The mill is now treating an average of 800 tpd.

Jan 1, 1970