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By K. Ogawa, T. Yokoyama

Hydraulic fracturing technique, an applied technique to cause tensile fractures to rock by injecting water pressure to a certain closed section of the borehole, is a measurement method of in-situ rock stress. This technique has the highest track record for techniques used in sub 1000 meter. A feature of this technique is comparatively simple and easy for in-situ stress measurement, because the measurement is applicable when a drilled borehole is available. The predominant advantage of this method is that elastic constants such as Young’s modulus and Poisson’s ratio are not required for determining the value and direction of initial stress. The factors to determine the stress state are the water pressures of re-opening and shut-in of fractures around the borehole wall and its directions. With conventional methods, however, the accuracy of the derived stress states from the observation equations was often adversely affected by the lack of consideration of the remaining water pressure in fractures and insufficient stiffness of the pressurization system. We have developed a new hydraulic fracturing system based on a new test method concept overcoming these defects, and applied to a 300 meter deep borehole in granite. The most important improvement of the new system is an employment of a syringe pump which enables an accurate flow control of fluid with less than 1ml/min in the pressure of 30MPa. Therefore the new test system has a quick response for pressurising in the interval zone, and the measured data was confirmed extremely accurate.

Jan 1, 2015

By R Zavadil, S Kuyucak, F Fazeli

Proton exchange membrane (PEM) fuel cells generate electricity by reacting hydrogen and oxygen. A thin, bipolar electrode material provides a medium for electron exchange with the electrolyte, alternately serving as anode at the hydrogen-rich side and cathode at the oxygen-rich side. Stainless steels have sufficient corrosion resistance to qualify as bipolar plate materials. However, the protective chromite layer increases the contact resistance, the battery’s internal resistance; and thus, decreases the electrical efficiency of the fuel cell. A heat-treatment is proposed and investigated via simulation by ThermoCalc / Dictra and experimentally, to generate a sufficient quantity of conducting surface carbides that breach the protective layer. Once carbide growth is arrested, a subsequent heat-treatment is also needed at a higher temperature to restore the corrosion resistance by filling-in the Cr-depleted layer (sensitization) around the carbide particles.

Jan 1, 2014

By F. P. Hassani, A. Hara, M. Momayez

To be competitive on the international market, the Canadian mining industry must reduce its costs, increase its productivity and maintain a high standard of safety. There is a great need today for improved methods that would allow the detection of geological structures in advance of mining to reduce dilution and the monitoring of underground structures to increase safety. This will facilitate planning for optimum exploitation of the mine and to increase production at lower costs. This paper discusses two examples of more efficient mine planning using new technologies such as Ground Probing Radar (GPR). In Kidd Creek mine, GPR technology was used at the 2500and 2600 levels to (1) monitor the stability of the sill pillar; (2) locate the presence of disseminated sulphide pockets in the sill pillar for extracting the mineral content; (3) monitor the stope backs and wall structures to evaluate the effect of on-time filling sequences; and (4)assess rockfill quality in terms of the presence of voids and fractures within the rockfilled areas. In the New Brunswick coal mine in Minto, GPR was used along with core log data to map and construct a 3D block of a section of the bench showing the relative position of different layers overlying the coal seam.

Jan 1, 1996

By K. A. Clark

A meeting between representatives of the Scientific and Industrial Research Council of Alberta and the Deputy Minister of Mines for Canada was held at Edmonton in May, 1929, for the purpose of formulating a co-operative plan for carrying forward studies in aid of the development of commercial methods for utilizing the bituminous sands of Alberta. It was agreed that to the Alberta Research Council should be allocated the general problem of investigation of the processes for the separating of bitumen from the sands, including studies of methods of emulsifying, dehydrating and otherwise preparing separated bitumen for industrial applications. It was further agreed that during the present year the work of the Alberta Research Council should be to continue its laboratory investigations of points of design of its separation plant; to further perfect its separation procedure; to recondition its existing separation plant at Dunvegan Yards, Edmonton, in the light of laboratory studies and to operate it for the purpose of demonstrating its efficiency; to carry on tests in emulsifying and dehydrating or otherwise preparing separated bitumen for industrial application; and on the basis of the experience gained in the operation of the preliminary plant at Dunvegan Yards to prepare and design and, as far as possible, to proceed with the erection of, a semi-commercial separation plant at a site to be chosen, probably at the bituminous sand deposits near McMurray, Alberta. This paper presents, in the main, a progress report of the carrying out of this programme.

Jan 1, 1929

By C. H. van Eendenburg

"Installation of a 3.6 km long raw coal conveyor in the Balmer open pit was undertaken to improve over-all haulage efficiency. This paper covers the rationale behind this project, system design and construction aspects and initial operating experiences. The majority of the construction work was performed by our own personnel. Where feasible, used equipment was installed to reduce capital cost and facilitate a tight construction schedule.BackgroundWestar Mining Ltd's Balmer Mine is located in the British Columbia Rockies, just outside of the town of Sparwood in the southeastern corner of British Columbia. The open pit mine, which has been in operation since 1969, currently produces about 6 million clean tonnes of coal per year, mostly for the metallurgical coal export market. Run-of-mine coal tonnages total between 9 and 9.5 million annually and waste removal volumes exceed 30 million bank cubic metres.The mine is a truck/shovel operation; loading equipment includes nine electric shovels, five front-end loaders and a hydraulic backhoe. The truck fleet consists of 40 units of 154-tonne, 181-tonne and 315-tonne capacity. The newer 154-tonne trucks are used for coal haulage for which they have been equipped , with tailgates to maximize their coal carrying capacity."

Jan 1, 1990

By M. K. Jain, Z. T. Xu, M. Bruhis, V. Hegedekatte

"Strain rate and temperature dependent deformation conditions are present during elevated temperature forming of aluminum and other metallic materials. While many constitutive laws have been proposed to represent such deformation conditions, a closer investigation often reveals their limited applicability in terms of fit to the experimental data, and interpolation within and extrapolation outside of the range of experimental stress-strain curves. This is often because material-specific primary deformation mechanisms of temperature-dependent strain and strain rate hardening are poorly captured. In the present work, the Voce-Kocks constitutive model based on mechanics of dislocations storage and annihilation has been found to be suitable for many metallic materials. The model was modified to include the effect of temperature dependent shear modulus. The modified model is then employed to represent the experimental data obtained from uniaxial tensile tests on AA7075-O sheet at elevated temperatures and strain rates. Also, hot gas bulging tests were conducted to verify the applicability of this model. Further, finite element simulation of the hot gas bulge test was performed by incorporating the model as a user material subroutine. Good general agreement was observed between the experimental and FE model predicted results. Some sources of discrepancy in the prediction are also discussed.INTRODUCTION There has been much interest in light-weighting of automobiles from automotive related industries to reduce overall carbon footprint and increase energy efficiency of the vehicles. Aluminum alloys, and especially the medium-strength 5xxx and 6xxx series alloys, have been the primary focus in the last 3 decades to reach the above environmental goals (Huo, Hou, Zhang, & Zhang, 2016) whereas aerospace industry has traditionally focused on high strength 7xxx series aluminum (Al-Zn-Mg-Cu) alloys for structural components (Deng, Yin, & Huang, 2011). Recently, there has been much interest in high strength 7xxx series aluminum as a replacement for heavier steel automotive structural parts such as A-pillar, B-pillar, side impact beams etc. (Harrison & Luckey, 2014). This is both interesting and challenging since the above aluminum structural parts will need to not only meet impact safety standards but also possess sufficient formability for manufacturing such complex parts. Since the formability of high strength 7xxx series materials is quite poor at room temperature, much interest has focused on improving both formability and final part strength via high rate hot stamping, in-die quenching, and subsequent artificial ageing process steps (Kumar & Ross, 2016)."

Jan 1, 2018

By Jun Wang, Bo Zhang, Wenqing Qin, Guanzhou Qiu, Xiaozhen Ma, Key Lab of Biohydrometallurgy of Ministry of Education, Fen Jiao, Central South University, Yansheng Zhang

"Arsenic contained in minerals sulphides such as enargite and tennantite can represent not only a significant penalty element in base metals production, but also a disadvantage to the environment through producing the toxic emissions to the atmosphere. The achieving separation of arsenic bearing minerals either at an early stage in floatation or from the floatation concentration is significantly beneficial to the economic. However, there was no feasible commercial method of separation at the flotation stage because of its similar flotation properties with many other copper sulphides. In this work, the selective floatation of enargite from copper sulphide concentrate containing maily covllite, chalcoctie, bornite and enargite was investigated. A low arsenic concentrate with As 0.2%, Cu 22% and a high arsenic bulk concentrate with As 7.65%,Cu 33.65% were obtained. It was indicated that Ca(ClO)2 is the effective depressor and the optimum floatation condition was obtained. Most enargite could be floated at pH 11 and controlling the pulp potential at 290 mV SHE. Furthermore, the arsenic removal from the high arsenic bulk concentrate by hydrometallurgy methods was study. The results showed that the reaction temperature and the concentrations of NaOH were the most important variables affecting the rate of arsenic removal. A low arsenic concentrate with As 0.24%, Cu 37.80% was obtained in the optimum leaching condition.INTRODUCTIONArsenic is mainly produced as a by-product of base metals smelting, in particular copper concentrate. China has imposed an upper limit of 0.50% arsenic for concentrates entering (Long et al., 2012). Arsenic amount of copper concentrate within 0.40% has also been imposed in China, and above which will be introduced about 50 RMB penalties per ton for each 0.10% increasing by smelters now. Therefore, it is necessary to remove arsenic from the copper concentrate.In copper concentrate, arsenic is mainly in the form of arsenopyrite (FeAsS), enargite (Cu3AsS4) or tennantite (Cu12As4S13). There are two types of arsenic in the separation of copper and arsenic: arsenopyrite and arsenic bearing copper mineral. It is easier to separate arsenopyrite from the copper sulphide by flotation in comparsion with the separation of enargite or tennantite from non-arsenic copper minerals (Pineda et al., 2015). The main difficulty in the separation of arsenic copper mineral from non-arsenic copper sulphides is their extremely similar floatability, which depends on the fact that tennantite and enargite contain high copper content (Pineda et al., 2015)."

Jan 1, 2016

By Arthur Dubé

An account is given of the developments brought about in the last fifteen years by metallurgical research in the field of heat treatment of steels. The practical aspects of these developments are especially emphasized. Methods of representation of the phase-change during austenitizing and sub-critical transformation of austenite are described and the importance of time-temperature-transformation charts for the planning of heat treatment cycles is shown. Special copies such as retained austenite and internal stresses developed on quenching are also discussed in some detail. Due to the interest shown currently in these problems, it has been thought advisable to describe briefly the underlying principles and present some of the results already available.

Jan 1, 1945

Thermal barrier coating (TBC) systems provide thermal insulation to high temperature for aero¬propulsion. A fracture mechanical model developed earlier for multilayer systems is applied on TBC to realize superior performance by enhancement of fracture resistance. Functionally gradient materials (FGM) solution concept is the basis of approach followed here. A few realistic FGM TBCs are considered in the analysis in addition to a conventional TBC as the base case and a hypothetical worst case with YSZ-YSZ interface. Parameters like number, composition and thickness of graded layers and elastic modulus are considered for the analysis and quantitative improvement of fracture resistance of TBCs. The analysis is confined to deep crack with crack size to width ratio as 0.5.

Jan 1, 2010

By W. M. Silva, Bittencourt. L. R. M.

Three newly developed alumino-silicate refractory bricks for use in safety lining of aluminum electrolysis cells were compared to one commonly used bricks for the same application. It was shown that the increase in silica content and decrease in permeability led to a sensitive decrease in cryolite attack. Both parameters are of utmost importance in selecting bricks for these cells. The reasons for this observation were the formation of a more viscous liquid after the reaction between molten cryolite and the brick, and the reduction of the rate of penetration. Moreover, a novel mortar with high silica content was tested and has shown improved resistance to molten cryolite. The use of oxidizing atmosphere led to increased attack rate in the brick when compared to reducing condition. The opposite effect was observed in the mortars.

Jan 1, 2004

By J M. Gibbs

Craigmont Mines Limited mine 50,000 tons of ore and waste per day from the open pit at Merritt, British Columbia. An electric-powered "down-the-hole" drill, a diesel-powered rotary drill and two electric-powered rotary drills have been used. All primary drilling, as a result of cost and operating experience, is now performed with two electric-powered rotary drills. Trials with various loading techniques have increased the amount of AN-FO and decreased the amount of commercially prepared slurries used for primary blasting. Approximately 95 per cent of the primary blasting is accomplished with AN -FO, mixed at the hole. Introduction THE Craigmont mine is located near the village of Merritt, B.C., 240 miles northeast of Vancouver. The concentrator has been in production since September of 1961. Craigmont is a combined open-pit and underground operation. To date, slightly more than 95 per cent of the mill feed has been mined from the open pit. As underground development proceeds, the ore requirements from the open pit will decrease. The average milling rate from September, 1961, to April, 1964, was approximately 4,900 tons per day.

Jan 1, 1965

By C. Yoo

"Geosynthetics engineering has made phenomenal advances during the last decade in areas of manufacturing as well as practical applications. As a result, geosynthetics are now being recognized as essential construction materials that can be used to facilitate construction, ensure better performance of the structures and reduce the long-term maintenance in routine civil engineering works. The creative use of geosynthetics in geo-engineering practice is expected to continuously expand as innovative materials and products are becoming available. In this paper, a wide variety of geosynthetic products available to geoengineers to solve a wide range of problems are briefly presented along with their functions and possible applications. Fundamentals of geotextile filter design principles are then introduced for use in the tunnel drainage system. Practical applications of geosynthetics relevant for tunnel engineering are also highlighted with emphasis on the issues associated with the geotextile filter application for use in the tunnel drainage system.INTRODUCTIONGeosynthetics have emerged as essential engineering materials in a wide range of civil engineering applications, e.g., transportation, geotechnical, geoenvironmental, hydraulics, and private development since the first geosynthetic conference in Paris, 1977 (Koerner 2012). Due to their costeffectiveness, ease of installation, and well established mechanical and hydraulic properties, geosynthetics are now playing important roles in the field of geo-engineering.As indicated in the 9th Bucahanan Lecture paper by Holtz (2001), major developments in civil engineering have only been possible with the parallel developments in the technology of construction materials. For example, larger scale structures became possible with the help of developments in concrete, reinforced concrete, and prestressed reinforced concrete technology which replaced wood and building stone as construction materials. The best example of a parallel development in geo-engineering between the material and the geotechnical application may perhaps be the soil reinforcement technology which has a direct analogy with reinforced concrete as a polymeric reinforcement material provides added level of tensile resistance and stability to soils that have little to no tensile strength, thus giving additional margin of safety."

Jan 1, 2015

By D. C. McDonald

"IntroductionTHE GIANT YELLOWKNIFE property is on the west side of Yellowknife bay, Great Slave lake, N.W.T., some 600 air miles north of Edmonton. This paper deals with the underground development and mining of the complex system of orebodies which have produced, in the first fifty-six months of operation (May, 1948, to December, 1952), 652,464 tons of ore with an average grade of 0.80 ounces of •gold per ton (1).The mine has been developed from three vertical shafts designated A, B, and C. Figure l shows the positions of these openings with respect to the known ore-bearing zones and the surface plant.A shaft was sunk to a depth of 522 feet in 1945-46, primarily as a prospect shaft for investigation and development of the East Zone orebody. Drifting was carried out on the 200-and 325-foot levels. Before this development had been completed it was clear that the funds immediately available made it imperative to get revenue from production as soon as possible. By the beginning of 1946, the remarkably high-grade character of the ore in the present B Shaft area had been established by surface drilling, and the decision was made to obtain initial production from this source. Since known orebodies at shallow horizons were to be developed quickly, the choice of a suitable rock outcrop for the shaft was something of a problem."

Jan 1, 1953

The effect of superficial gas rate distribution (Jg profile) on down-the-bank metallurgical response was tested in the rougher-scavenger bank (eight 10-m3 tank cells, 4 roughers and 4 scavengers) at Highland Valley Copper Mine's Cu/Mo separation circuit. Three Jg profiles were tested: (a) as found (i.e., typical practice), (b) increasing decreasing (i.e., increasing from cell 1 to 4 and decreasing from cell 5 to 8), and (c) decreasing-increasing (i.e., decreasing from cell 1 to 4 and increasing from cell 5 to 8). The Jg profile approach proved to be of considerable value. Profile (b) gave the best metallurgical results, i.e., the highest down-the-bank grade/recovery (increase in grade at constant recovery was approx. 3-4% compared to the as found case) and the most efficient Cu/Mo separation (cumulative Cu recovery was reduced by almost half - approx. from 20% to 12%, at 99% Mo recovery). The success of the evaluation prompted the implementation of profile (b). Detailed gas dispersion characterization tests (Jg and Db (bubble size)) showed significant discrepancies between the Jg measured directly (using the McGill University sensor) and the Jg calculated from field instrument readings (volumetric gas flowmeter) and machine dimensions (cell cross-sectional area). Tests were designed to reveal the source of disagreement. It was observed that a significant number of bubbles were not able to float (i.e., they were entrained with the tailings), the evidence appearing to be a significant number of very small bubbles (approx. 200-300 µm) which did not have sufficient buoyancy to rise. Consequently, rather than relying on the field instrument, the evaluation depended on the McGill University Jg sensor, which collects bubbles in a tube near the pulp-froth interface, thus providing significance to the data as the measurements were obtained from bubbles that almost certainly floated.

Jan 1, 2007

By Shuji Owada

Scrap electrical and electronic appliances, so called "E-waste", are not a present target to be collected and recycled under Japanese regulations. This material, however, contains considerable amounts of base, precious, and rare metals and it is necessary to recover these elements for maintaining stable supply and establishing "the society of environmentally-sound material-cycle". This paper describes recent trends of rare metals recycling in Japan and technological approaches to achieve the above objective. Also a research work to concentrate rare metals from the printed wiring boards by combining brand new comminution and physical separation methods is discussed.

Jan 1, 2011

By L. K. Daneshmend

Key issues in managing information systems in the minerals industry will likely continue to be those relating to the integration and interoperability of disparate systems. This paper argues that, in order to harness the promised benefits of information technologies, the mining industry should adopt a set of open systems standards to define data formats and protocols for seamless data exchange. This is in direct contrast to the present situation where mining equipment, software and instrument suppliers rigidly adhere to proprietary standards for fear of losing competitive advantage. Benefits to the mining sector resulting from the adoption of such standards would be: the provision of near-time data for executive decision support, and the freedom to choose best technologies. The principal benefits to the leading mining software suppliers will be increased market share as a result of “captive sites” converting to open systems standards. Examples are given of open systems standards developed for related industries such as the Petroleum Open Systems Corporation (POSC) and the Machinery Information Management Open Systems Alliance (MIMOSA).

Jan 1, 2000

By A. Yaghini, Y. Pourrahimian

"Human factors (HFs) play an important role in the mining and mineral industry, affecting operational and maintenance efficiency and safety. Despite the introduction of new technologies and automation in this sector, it is well known that a significantly large proportion of total human errors occur during the operation and maintenance phase. A comprehensive literature review of HFs across several industries is provided. From this review, the impact of HFs on operation and maintenance is summarized, with a focus on what the mining industry is currently doing and what opportunities exist for additional improvements. Future research directions and themes are also identified.RÉSUMÉ Les facteurs humains (FH) jouent un rôle important dans l’industrie des mines et des minéraux, en ce qu’ils affectent l’efficacité et la sécurité de l’exploitation et de l’entretien. Malgré l’apparition de nouvelles technologies et de l’automatisation dans ce secteur, il est bien connu qu’une grande partie des erreurs humaines (EH) se produisent durant une phase d’exploitation et d’entretien. Cet article propose une analyse documentaire approfondie des FH dans plusieurs secteurs. L’impact des FH sur l’exploitation et l’entretien est résumé à partir de cette analyse, une attention particulière étant accordée à l’évolution de l’industrie minière et aux possibilités d’améliorer davantage ses activités. Sont également identifiés les futurs thèmes et voies de recherche.INTRODUCTIONDuring the past several decades, the mining industry has focused on improving equipment, machinery, and methods that have led to more advanced hardware and software, equipment with higher reliability and productivity, and other technological advancements. These actions have improved safety and productivity and have reduced casualties and maintenance workload. Although today’s mining equipment and machinery are technologically advanced and highly reliable, the risk of accidents is still relatively high and key performance indicators have not improved significantly compared to other industries (Sorensen, 2012). A prominent reason could be due to insignificant integration of human factors (HFs) as part of planning, operation, and maintenance activities. The current mining system is a people system, and inevitably HFs and human error (HE) figure prominently in all aspects of this industry. Even the most advanced technologies and innovations require operators and maintainers with significant knowledge and skill, which could increase the potential for HE."

Jan 1, 2018

By Vladislava A. Ignatkina, Fillip O. Milovich, Vladimir A. Bocharov

"Complex research of flotation concentrates of monomineral fractions of chalcopyrite, sphalerite, galena, pyrite, pyrrhotite included methods of adsorption of collectors, surface compounds by IR ATR, and surface films of flotoreagents by TEM. They revealed that the proportion of the parts of thionocarbamate (TC) and dithiophosphate had an effect on the adsorption rate of the components of minerals, on the presence of characteristic bands, and, what is an important, visualized surface film of organic flotation reagents on the particles of concentrates by TEM. The predominance of thionocarbamate in a composition selectively increases the adsorption rate constant of the components and recovery of chalcopyrite compared with sphalerite and galena. The highest flotation rate using TC is characteristic for chalcopyrite (0.62 min- 1) in case of individual use, and it's in combination with butyl xanthate (25% butyl xanthate or 3:1) 0.89 min-1 too. We studied the ternary blend - dithiophosphate: thionocarbamates: butyl xanthate. The increase of the proportion of butyl xanthate in combination reduces the contrast of the flotation rate among all sulfides.Practice flotation of refractory sulfide copper-zinc ores of the Urals (content sulfide iron - 75- 95%) confirmed that the use of a combination of selective collectors increases selective recovery of copper sulfide minerals up to 50% at the first fraction that is the conditioned copper concentrate. New selective sulfhydryl collectors resulted in high levels of recovery of copper into a concentrate - more than 90% - against 70-72% (butyl xanthate) from copper-pyrite ore. Low floatability of iron sulfides has been obtained by selective sulfhydryl collectors. Using weak selective sulfhydryl collectors can reduce pH into collective or selective flotation from pH 10-10.5 to pH = 7.2-7.5, which improves the quality of individual concentrates of nonferrous metals and their recovery. The same is true for polymetalic sulfide ore. The volume of gold recovery also increased."

Jan 1, 2016

By K. Purazrang, P. Sh. Naseri, P. Abachi

In present work, the comparative measurement of aluminum alloys' resistance to the unstable fracture was provided. Besides, the rupture mechanisms of high strength 7075 and 7050 aluminum alloys were investigated. The specimens were used as solution treated, quenched and aged condition. The elastic-plastic behavior of specimens was determined by carrying out tensile test on cylindrical specimens. The small sized specimen with 6.35 mm thickness and V-notched radius less than 60 µm was used for evaluation of damage properties, in accordance with ASTM B871-96 standard test method. All tear specimens were machined in L-T orientation. The mechanical tests were conducted at RT on an universal Instron machine under cross head speed of 0.1 mm/min. The results of mechanical tests made the evaluation of tear strength to 0.2 % tensile yield strength ratio, as a measure of notch toughness, available. The comparison of specimens' resistance to crack propagation and unstable fracture due to the presence of crack-like strain concentrator was provided using tear test data. The microstructure of specimens was studied under optical microscopy. The rupture micro-mechanisms were analyzed by examination of specimens fracture surfaces using SEM. The microstructure examination indicated almost equiaxed grains on the transverse directions and elongated grains on rolling direction. Moreover, intermetallic particles were evident at microstructure. Considering the SEM fractographs, it seems that the intermetallic particles act as void nucleation and damage initiation sites. However, the damage mechanism of tensile specimens and severely notched specimens, especially near the notched root differs due to stress and strain states.

Jan 1, 2006

By M. Kuyumcu

After German reunification the mining industry in former East Germany was profoundly restructured. Beside privatization of profitable companies the public sector took over responsibility for the mining operations to be shut down. Therefore state-owned companies cope with technical, ecological, and social challenges. The rehabilitation and reclamation has to rededicate former mining areas to new use and provided new jobs as well. In the lignite mining districts there are around 100,000 ha of mining area, a mining caused disturbance to the groundwater balance and to the system of surface water bodies of approx. 390,000 ha. They are called the largest landscape construction site in Europe. In addition to the results and diverse experience achieved over the past 23 years, a description will follow of our new challenges and of an outlook on remaining tasks. This article will describe the financing, as well as aspects of the jobcreation policy arising from lignite industry remediation.

Aug 1, 2013