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By J. Schmidt

The development of set of laboratory experiments, intended to help undergraduate students meet Canadian Engineering Accreditation Board requirements for Engineering Design outcomes, is described.The laboratory, which is part of a third year level course in hydrometallurgy, is aimed at advancing the ability of students to generate and use experimental results to design an industrial copper leach/SX/EW plant. Emphasis is placed on the students demonstrating the ability to use of their engineering knowledge in weighing the pros and cons of the various process options that they test in converging to a final flowsheet. INTRODUCTION Over the past number of years the Canadian Engineering Accreditation Board, CEAB, has dramatically shifted the way that they evaluate undergraduate programs. In the past, the focus was on measuring of the quantity and quality of material the students were intended to learn as well as the methods and resources used to deliver that material. Now, rather than principally evaluating the inputs of programs, the focus is more on measuring the quality of the outputs from the programs, i.e. the quality of graduating students. In this regard, the CEAB has developed a list of twelve attributes that learners must develop in the course of their studies. Engineering programs must, not only demonstrate that their curriculums provide opportunities to develop these attributes, but must measure student proficiency in each of these attributes as they progress toward graduation. One particular graduate attribute that Laurentian University’s Bharti School of Engineering has encouraged its faculty members to develop content for is “design”. Engineering Canada (2018) defines this attribute as “an ability to design solutions for complex, open-ended engineering problems and to design systems, components or processes that meet specified needs with appropriate attention to health and safety risks, applicable standards, and economic, environmental, cultural and societal considerations”. The previous laboratory component for the hydrometallurgy course was a collection of unconnected experiments covering leaching, solvent extraction, ion exchange, and electrowinning. Like in other undergraduate courses, students would perform stand-alone experiments, make the specified measurements, do the specified analyses of the results, and report the findings, all as strictly detailed in the lab manual. The vision for the new lab was to create an experience that would more closely mimic an industrial research program whereby students would start with a given feed material and would progress through a series of connected experiments. Emphasis is placed on the student demonstrating competency in, not only, generating and analyzing experimental data, but also in using the data along with their engineering knowledge to design and evaluate the pros and cons various plant configuration options. Principally, students are asked to weigh cost, safety, and environmental concerns in converging to their final flowsheet. In designed the leach circuit, students must weigh the costs/benefits of varying leach temperature. Higher leach temperatures will yield faster and more complete copper dissolution, which will allow for the specification of relatively smaller leaching circuits, saving capital costs. However, hotter acid solutions are more dangerous to handle and require increasing amounts of energy to heat the slurry, increasing operating costs. In solid/liquid separation, students must weigh the pros and cons of the addition of a flocculent to assist settling. The flocculant will allow for the design of a thickener circuit that employs units with a relatively smaller area, but will result in a thickener underflow with a lower pulp density, which may necessitate a larger number of thickeners. In addition, the environmental concerns of producing a tailings product that contains an organic contaminant should be addressed. In solvent extraction, students must specify the number of stages of loading and stripping, as well as organic and aqueous flowrates to produce suitable raffinate and rich electrolyte streams. Finally, in electrowinning, students will compare the costs/benefits and risks of the use of precious metal coated titanium dimensionally stable anodes (DSAs) versus conventional Pb based anodes.

Jan 1, 2019

By J. C. Keenan

Company-community agreements are widely considered to be a practical mechanism for recognising the rights, needs and priorities of peoples impacted by mining, for managing impacts and ensuring that miningderived benefits are shared. The use and application of company?community agreements is increasing globally. Notwithstanding the utility of agreements, the gender dimensions of agreement processes in mining have rarely been studied. Prior research on women and mining, however, does show that women are often more adversely impacted by mining than men, and face greater challenges in accessing development opportunities that mining can bring, however there is currently little to no guidance for companies, government or communities in terms of bringing a gender perspective to the fore in mining and agreement processes. While it is undisputed in human development literature that investment in women and sensitivity to gender delivers long-term health, education and local development outcomes, a number of key factors remain unexplored in debates about mining and development. These include: women?s participation in agreement processes, the gendered distribution of agreement benefits, and the extent to which impacts and benefits influence (either positively or negatively) women?s development and economic inclusion. This paper presents the results of an applied research project undertaken by the Centre for Social Responsibility in Mining (CSRM) at The University of Queensland and funded by a partnership between the Minerals Council of Australia (MCA) and the Australian Agency for International Development (AusAID). The project sought to connect with practitioners who had been directly involved in agreement processes to hear grounded perspectives on the interaction of gender dynamics and agreements, and connect those experiences with the broader literature. Findings from this study have implications for the role of companies and governments in promoting gender equality and empowerment as part of their commitments to sustainable development. A key challenge for companies will be navigating the territory of cultural norms and gender equality. The authors argue that without consideration of the gender perspective, and appropriate responses, mining agreements may not be inclusive or representative and may exacerbate gender inequalities and fail to contribute to long-term sustainable development.

Aug 1, 2013

By P. Sauriol

This work addresses the design challenges and demonstrates the capabilities of a novel water transfer factor measurement apparatus. Several measurement concepts were screened on the basis of their water transfer factor accuracy using Monte-Carlo generated virtual experiments. The most promising measurement concept was assembled and tested to assess its actual measurement accuracy. For these concept validation experiments, the polymer electrolyte membrane fuel cell was simulated by adjusting the water injection rate to corresponding levels. Combining the anode and cathode measurements, the water transfer factor accuracy was typically better than 0.01. Real-time measurements of the water transfer factor on both anode and cathode sides of a polymer electrolyte membrane fuel cell were achieved. The anode and cathode side measurements were in good agreement with each other; however the anode side measurements were generally more reproducible. A parametric study showed that stream humidification plays an important part in the water transfer across the membrane electrode assembly. Finally the water transfer factor along the channel of a 300cm2 co-current fuel cell was obtained by using a series of six 50cm2 sub cells. The results were in good agreement with predictions from a recently proposed model.

Jan 1, 2005

By T. J. Langan, M. Ramajayam, T. Dorin

"6xxx-series Al alloys are the most commonly used alloys in the automotive industry as they have an appropriate balance of strength, corrosion resistance and formability. The main strengthening phase in these alloys is the ß’-Mg2Si precipitates. One opportunity to achieve stronger 6xxx-series Al alloys, without affecting corrosion and formability, is the use of Sc. The main challenge of using Sc in 6xxx-series lies in the heat treatment, which must be designed to allow for a fine precipitation of both Al3Sc and ß’-Mg2Si. In this work, two model alloys are used, an Al-Sc-Zr and an Al-Mg-Si-Cu-Sc-Zr, to explore the impact of the 6xxx-series key elements (Mg, Si and Cu) on the Al3Sc precipitates. Transmission electron microscopy and atom probe tomography are used to investigate the precipitates present in the microstructure after casting. We find that higher Si content results in the formation of dispersoids upon casting. The average composition of these dispersoids is (Al0.8,Si0.2)3 (Sc0.888,Zr0.024,Mg0.08,Cu0.008). A closer look at the solid solution reveals that most of the Sc and Zr is supersaturated after casting even in the presence of Mg, Si and Cu. We discuss the impact of these results on the design of a suitable heat treatment for 6xxx-series alloys with Sc.INTRODUCTION The most common strategy to strengthen aluminum (Al) alloys is by micro-alloying to form a fine distribution of precipitates (Gladman, 1999). Whilst precipitates enhance the strength, this is often done to the detriment of ductility and corrosion performance (Davis, 1999). The 6xxx-series Al alloys are heavily used in the automotive industry as they offer an appropriate balance of strength, ductility and corrosion resistance (W. S. Miller et al., 2000). The strength increment in these alloys comes from the formation of the ß’–Mg2Si and the quaternary Q’ phase (Chakrabarti & Laughlin, 2004; Polmear, St. John, Nie, & Qian, 2017). One opportunity to achieve stronger 6xxx-series alloys, whilst keeping good balance of corrosion resistance and formability, is the use of small additions of scandium (Sc). Sc is one of the most potent strengtheners in Al alloys (Dorin, Ramajayam, Vahid, & Langan, 2018; Røyset & Ryum, 2005). Most of the strengthening benefits from Sc come from the formation of fine Al3Sc dispersoids. The following strengthening mechanisms apply to Sc: 1) Solid solution strengthening, 2) precipitation hardening, 3) inhibiting recrystallization, 4) assisting nucleation of other strengthening phases (Dorin, Ramajayam, Lamb, & Langan, 2017). As compared to other dispersoid phases, Al3Sc dispersoids have good electrochemical compatibility with Al alloys and hence do not affect their corrosion resistance (Cavanaugh, Birbilis, Buchheit, & Bovard, 2007). The coarsening resistance of Al3Sc is often improved by adding zirconium (Zr), as it forms a Zr rich shell around Al3Sc which prevents Sc from moving across the interface."

Jan 1, 2018

By Yoshimasa Funakawa, Kazuhiro Seto, Akio Kobayashi

A new hot rolled high strength steel consisting of ferrite matrix and nanometer¬sized precipitates was developed. The ultra fine precipitates were identified as TiMoC2, and the strengthening by the precipitates was evaluated more than 300MPa in case of TS/800MPa grade steel. Due to the strengthening effect of the ultra fine precipitates, alloy elements for solid solution hardening can be reduced. It is notable that the steel shows very high yield strength (730MPa in case of TS/800MPa) and very high local elongation leading to excellent stretch flange formability at the same time. The mechanical properties of the steel are attractive for chassis parts and structural parts of auto body. The steel has been produced commercially, and applied to the parts successfully.

Jan 1, 2004

By Su-Ping Peng

Three dimensional (3D) seismic exploration has been carried out since the 1980s in the mining district of China, where it has been playing an indispensable role in the high yield and efficiency of coal mining. Unlike oil exploration, this technique uses high density seismic acquisition technology. In recent years, it has focused on wide azimuth 3D seismic acquisition. Evaluation of geometry moved away from depending on folds, azimuth and offset, toward being based upon a focus-ray beam. Conventionally, coalfield 3D seismic interpretation focused on time domain and was based on kinematics information, which is only suitable for less complex geological conditions. To achieve high-resolution processing for the complex topography and structure in coalfields, data processing shifted from poststack to prestack. The means to improve the accuracy of interpretation for complex geological conditions are 1) integration of multiple attributes and multiple disciplines, 2) combination of seismic and geological data, and 3) comprehensive combination of time domain and depth domain data. With the demand for lithological exploration, high-resolution data processing must also take into account the requirements of preserving amplitude in seismic data. Seismic attributes technology, seismic inversion technology, and dynamic tracking interpretation are key techniques in 3D seismic exploration. They greatly improve interpretation accuracy, produce better results in the goaf space description of the coal-bearing strata and coal seam structure, and effectively reduce exploration costs under complicated geological conditions. Therefore, these techniques will be the primary means employed in the future to deal with coalfield complex structure and lithological exploration.

Aug 1, 2013

By P. Chryssanthakis

"The aim of this study is to give a better understanding for the behaviour of the composite material RRS and the synergy effect of its components while an excavation face advances during tunneling. The lower part of the Q-system scale (i.e. Q-values of 0.4 or less for a tunnel span of 10 m) is commonly used for tunnel applications in softer rock formations. This is implied in the updated Q-chart, where the dimensioning of rock support by using Reinforced Ribs of Shotcrete (RRS) comprises the use of fiber reinforced shotcrete, S(fr), rock bolts and shotcreted beams reinforced with steel rebars. The newest part of the lower part of the Q-chart gives more information on required support compared to older Q-system versions. The RRS can be described as a three part composite material with the 3rd component being the reinforced concrete beam (with no fibers) and with steel rebars that are placed in groups and sprayed with pneumatically applied shotcrete in layers. The RRS usually have a total thickness varying between 0.20 and 0.50 m and a width between 0.25 and 0.60 m respectively. They are placed at different distances along the tunnel axis depending on the rock mass quality.In this study, an effort has been made to simulate RRS in a numerical code and to study its behaviour in a real case study. A double tube, triple lane tunnel in weathered tuff has been chosen as reference material for testing RRS under changing load. This was done by writing a FISH subroutine which is implemented in the discontinuous numerical code Universal Distinct Element Code (UDEC) that takes into account the characteristics of the reinforced beam (height, width, number of steel rebars, and spacing) in the calculation process. A rather extensive parametric study has been run by using the same key input rock mass parameters and in situ stresses (?H/?v = 0.5), and changing only the RRS key input parameters in order to simulate the changing loads during the face excavation process in tunneling. The critical part of this numerical modelling work that is under investigation in this study, is the period just after the excavation: i.e 4 hours; 16 hours after excavation; and finally after the complete curing (28 days) of the cement based components. The RRS are installed in three consecutive steps as follows: a) the application of S(fr) on the rock surface in order to even it up for the RRS application; b) radial bolting; and c) installation of the reinforcing steel rebars, that form the reinforced beam.The results show that: a) the S(fr) is almost overloaded in the first 4 hours after application in both tunnels; b) on the S(fr) and steel rebars, the stresses, axial and shear loads, as well as moments are decreasing after 16 hours and 28 days; and c) the bolts loads are increasing with time. The observed reduction in stresses and loads in both the S(fr) and reinforced beam is surprising. A possible explanation is that tunnel arches are self-supported to a lesser extent as time progresses due to redistribution of stresses in the nearby rock mass through the radial bolts. The loads in radial bolts are increasing by almost 25%. This can be seen from the overall results as we observe an increase in maximum principal stresses, displacements, shear displacements along joints and hydraulic apertures compared to tunnel baseline that has no support of any kind."

Jan 1, 2015

By D. S. Salonine

Aluminum alloys are widely used in modern industry. Tubes and hollow shapes give great opportunities for structural purposes as well as fluid transport due to their stiffness and lightness, Extrusions on a mandrel or through a bridge die, that requires splitting of the billet with re-welding, produce hollow shapes with varied contours, fins and multiple cavities. Moving and stationary mandrels, mandrel lubrication, tooling for ribbed-tube heat exchangers, and for drilling pipes are considered. Bridge dies can be classified by the bridge position relative to the die face, by mandrel support structure, and by assembly type, The main parameters influencing the quality of the die-welded seams are considered, The difficulties of extruding various alloys through bridge dies are discussed in terms of metallurgical factors, Some approaches to the calculation of the stresses in a bridge are presented.

Jan 1, 2005

When selecting a method for monitoring crack growth in pipeline steel, the sensitivity or crack-size resolution plays a dominant role. Even though there are several visual and non-visual methods, the direct current potential drop (DCPD) method is very effective for monitoring crack growth because of its resolution. This method has been used for the past few decades and has gained increasingly wide acceptance in fracture research as one of the most accurate and efficient methods for monitoring the propagation of cracks. Furthermore, most R&D experience has proven that the electrical potential method can be used in most "aggressive" environments. For these reasons, the DCPD method was selected to design a testing machine to monitor corrosion fatigue crack growth. The use of finite-element modelling is shown to facilitate the application of the DCPD method for monitoring crack growth in steels. The 2D model calibration provided a good description of the test data and proved more accurate than the analytic Johnson's formula.

Jan 1, 2005

By D. Bois, P. Keating, J. Lemieux, M. A. Vallée, M. Allard, R. S. Smith, L. Z. Cheng, M. Chouteau, D. K. Fountain

"Abstract -A test survey using the MEGATEMII airborne electromagnetic system was flown over the Iso and New Insco massive sulfide orebodies in the Rouyn-Noranda mining camp, Canada. The results were compared with data from historical systems (INPUT, DIGHEM) used to discover the deposits. The historical data show that the two deposits have comparable conductances. However, the modern MEGATEMII system reveals that the New Insco deposit has a much slower decay than the Iso deposit, and it is, therefore, interpreted to be more conductive. The MEGATEMII anomaly maps provide estimates of the location, depth, dip, and strike of the two deposits, information that was not available from the historical anomaly maps. The signal-to-noise ratio of the MEGATEMII data is greater than the historical data, yielding more sharply defined anomalies. The investigations also included a comparison between 90 Hz and 30 Hz MEGATEMII data. The 90 Hz data were found to be useful for mapping the less conductive parts of the Iso body, whereas the 30 Hz data demonstrated that the New Insco body is more conductive. Analysis of height attenuation data over the Iso body indicates that the body could be seen by the MEGATEMII system if it were buried an additional 230 m deeper (in highly resistive material). On the other hand, the INPUT system would detect the Iso body only if it were buried no deeper than an additional 60 m. Tests with the transmitter turned off showed that, for this flight, the MEGATEMII system noise levels on the processed data are about 300 pT/s. Sommaire - Dans le cadre d’un projet de recherche, un ensemble de levés d’essais électromagnétiques aéroportés employant le système de MEGATEMII a été effectué au dessus des dépôts d’Iso et de New Insco, Rouyn-Noranda, Canada. Les données ont été comparées avec les réponses des systèmes qui ont découvert ces deux dépôts (INPUT et DIGHEM). Les données antérieures montrent que le dépôt d’Iso a une conductance comparable à celle de New Insco. Cependant, les données de MEGATEMII démontrent que le dépôt de New Insco a une haute valeur de la constante de décroissance, ce qui reflète une plus forte conductivité. La carte d’anomalies de MEGATEMII indique la localisation, la profondeur, le pendage et l’orientation des deux dépôts, ce que la carte d’anomalies antérieure ne montrait pas. Le rapport de signal à bruit de MEGATEMII est plus grand que celui des données de INPUT et de DIGHEM; de plus, les pics sont mieux définis. Les tests ont également permis une comparaison entre les fréquences de base de 90 Hz et de 30 Hz. Les données de 90 Hz se sont montrées utiles pour cartographier la partie du dépôt Iso dont la conductivité est la plus faible, tandis que les données de 30 Hz montrent clairement que le dépôt de New Insco est plus conducteur. Les analyses de l’atténuation du signal avec la hauteur ont indiqué que le dépôt d’Iso pourrait être détecté par le système MEGATEMII s’il était enfoui à 230 m sous la surface (dans un milieu hautement résistant). D’autre part, le système INPUT pourrait seulement détecter le dépôt d’Iso s’l était situé à 60 m de profondeur. Les tests avec l’émetteur fermé démontrent que le niveau de bruit est des l’ordre de ±300 pT/s."

Jan 1, 2006

By J. Duby

"A description is given of a series of tests performed to determine the comparative effects which dynamic and static straining, in compression, have on the physical strength properties of mild steel and an aluminum alloy. The dynamic deformation was imposed during the passage of single stress pulses of about 100 micro-second duration. These pulses were recorded with strain gauges mounted near both ends of the specimen. The resulting records were analysed using a simple wave theory; there from the dynamic stress-strain curves for the respective metals were deter-mined and were then compared with the static stress-strain relation. The respective hardnesses of the metals after deformation are evaluates by means of static stress-strain curves in compression. The micro-structures of the metals before and after deformation are also shown. It is observed that dynamic de-formation considerably modifies the rate of strain hardening. This modified hardening appears to be persistent. The observed differences in physical strength properties and micro-structures are discussed in the light of the accepted dislocation theory for metals."

Jan 1, 1960

By Arnold Blaisonneau, Théophile Guillon, Xavier Rachez, Sylvie Gentier

"L’étude présentée ici vise à étudier l’influence, lors de stimulation hydraulique de puits dans les réservoirs géothermiques de type Enhanced Geothermal System (EGS), du comportement mécanique des zones de failles recoupant le puits sur la réponse hydraulique du réseau de fractures 3D. Dans ce but, un modèle 3D, basé sur la méthode des éléments distincts et dans lequel les zones de failles recoupant le puits sont modélisées par des fractures numériques 2D, est mis en oeuvre. Les modélisations présentées ici visent à caractériser l’influence du comportement mécanique (type de comportement, hétérogénéité) sur la cinétique de la stimulation hydraulique, ainsi que sur son effet spatial autour du puits. INTRODUCTIONPour le développement de l’exploitation géothermique de type Enhanced Geothermal System (EGS), la phase de stimulation conditionne grandement le succés du projet ; en effet, elle a pour objectif d’augmenter l’injectivité et la productivité des puits et doit permettre d’assurer la connexion entre les puits d’injection et de production garantissant ainsi la viabilité technique et économique de l’échangeur. Pour le site EGS de Soultz-sous-Forêts (France), parmi différentes techniques de stimulation, la stimulation hydraulique a été utilisée à cette fin en provoquant une augmentation irréversible de la perméabilité autour des puits. Dans ce type de réservoirs fracturés, le but des stimulations hydrauliques est de réactiver, plus spécifiquement en cisaillement, des structures hydrauliques pré-existantes (fractures, zones de failles etc.) dans le socle cristallin. La compréhension des phénomènes physiques durant la stimulation hydraulique est cruciale pour optimiser cette technologie et pour contrôler/limiter les risques associés (viabilité technique et économique des puits, sismicité induite etc.). C’est notamment le cas pour la relation entre le comportement mécanique des structures stimulées et les conséquences sur le comportement hydraulique dans un contexte tectonique spécifique."

Jan 1, 2015

By K. Forsberg, A. Rasmuson, R. Rodriguez Varela, J. Martinez De La Cruz

"This study analyzes the separation of rare earth elements by means of a supported liquid membrane (SLM) with the final objective of recovering REE from an apatite concentrate (Alemrajabi, Forsberg, & Rasmuson, 2015; Mohammadi, Forsberg, Martinez de la Cruz, & Rasmuson, 2015). In this study, the feed phase consists of an aqueous phase containing REE, the membrane phase contains the organic solvent and carrier (D2EHPA and EHEHPA), and the stripping phase is a hydrochloric acid solution. An evaluation of mass fluxes, separation efficiency, and membrane performance is conducted. In order to analyze the suitability of liquid membranes in the extraction of REE, a deeper insight into the mechanisms causing instability is needed. In this study, surface tension is considered as the key factor of Marangoni instabilities and spontaneous emulsification.INTRODUCTIONThe demand of REE and their compounds has increased considerably due to their special physicochemical features that make them crucial elements for numerous high-tech applications, including wind turbines, hybrid cars, mobile phones, and defense technologies. They are also extensively utilized in traditional industries such as nuclear energy, petroleum, metallurgy, agriculture, and textiles (Xie, Zhang, Dreisinger, & Dyole, 2014; Zhang, Wu, Bian, & Zeng, 2014).Solvent extraction is widely used for the separation of REE (Xie et al., 2014; Zhao, Huo, Pan, Li, & Liu, 2014). Di-(2-ethylhexyl)-phosphoric acid (D2EHPA) and 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (EHEHPA) are two of the most effective extractants for the separation of rare earth elements among organophosphorus extractants (Gupta & Krishnamurthy, 2005). However, the difficulty in stripping loaded D2EHPA extractant, especially for heavy REE, has limited its utilization. Yttrium can be stripped at lower acidities in EHEHPA systems compared to D2EHPA systems (Gupta et al., 2005), but the extraction efficiency is lower. Conventional solvent extraction by mixer-settlers is restricted by its large solvent inventory and loading limits, and suffers from phase disengagement, emulsification, loss of solvent, and flooding problems (Swain, Jeong, Lee, & Lee, 2007). In this context, supported liquid membranes (SLMs) present a potential alternative due to their advantages, being low solvent inventory, process simplicity, low energy and operational costs, great enrichment ratio, and combination of extraction and stripping into one single step. A SLM is a system in which two aqueous phases are separated by an organic liquid membrane suspended in the pores of a porous support by capillary forces. One of the aqueous phases is the feed solution with the solute and the other is the stripping or receiving solution. The solute diffuses through the liquid membrane and then is extracted into the stripping solution (Kislik, 2010)."

Jan 1, 2016

By Grazyna Zakrzewska-Trznadel

The paper outlines the main objectives of the project that concern the evaluation of the possibility of uranium production from indigenous resources since Poland enters the nuclear program. The best available technologies are considered for uranium extraction and obtaining the yellow cake - U3O8. Liquid-liquid extraction with novel extracting agents, as well as membrane processes for separation of by-products will be tested in course of the project. The technological part will be completed with techno-economical analysis. Acknowledgement The studies were supported by the POIG project, No 01.01.02-14-094-09-00 ?Analysis of the possibility of uranium supply from domestic resources?.

Aug 1, 2010

By E. C. De Matos

The Uranium Province of Lagoa Real is located in the mid-south region of Bahia State, Brazil. Uranium is the only mineral wealth, occurring mainly in the form of uraninite. The region has been searched for uranium since 1971 and 35 anomalies were detected, distributed over 1200 km2. Seven are now taken as deposits, accounting for reasonably assured resources of 100.000 tons of U3O8. This paper describes the geological aspects of the area, the exploration and mining activities done so far by the state company INB and the perspectives for the near future, when a raise in the country?s uranium demand is expected.

Aug 1, 2010

By S. C. Tadolini

"Roof bolts are the primary means of roof support in underground mines in the United States. Presently, post installation loads are measured on about 10% of the expansion anchor and combination bolts by using standard torque wrenches that Unit the accuracy of the measurements to about ±30%. No system has been available for measuring the loads generated on full-column resin grouted bolts. Mine roof bolts are long, slender, non-uniformly sized, roughly forged, and placed in a corrosive environment, creating obstacles for researchers trying to utilize ultrasonic reflection techniques to measure strain. A complete measurement system has now been developed by the U.S. Bureau of Mines, Denver Research Center. This system is being used successfully in determining loads measured on expansion anchor and combination bolting systems, examining the transfer mechanics of full-column, resin-grouted bolts, and measuring loads generated on bolts in an underground roadway support system.IntroductionMillions of roof bolts are used each year to provide structural support in underground U.S. metal, non-metal, and coal mines. Approximately 45% of the bolts used are expansion anchor, 45% are resin-assisted combination or full-column resin-grouted, and 10% are friction anchored. The effectiveness of these bolting types is dependent on a number of factors including rock density, bolt length, in situ stresses, rock properties, bolt pattern, installation tension, etc. When implementing expansion anchor and resin assisted combination bolts , installation and post-installation tension, or load, is a major determinant of support quality and subsequent behaviour of the reinforced roof. The method by which these systems carry roof loads is well understood and documented(1,2).The importance of these installation and long-term bolt tension measurements is well recognized and are required in the federal government regulations(3). A statistical sample of the bolts, lout of 4 during installation and lout of 10 inby the last open crosscut, is required to be measured using current torque wrench technology. The disadvantages of this system are the disturbance and weakening of the anchorage and limitations of accuracy to approximately ± 30%. The method by which resin-grouted bolting systems carry roof loads is much less understood, mainly because testing procedures used to evaluate point-anchor systems are not effective on resin-grouted bolts.Due to these problems, the U.S. Bureau of Mines designed a measurement technique that provided a highly accurate, low cost-per- bolt system that led to the development of ultrasonic pulse echo instrumentation. The original system was designed to measure the tension only on expansion anchor bolts. Recent developments and system modifications have permitted measurements on resin-assisted and full-column resin-grouted bolts. The use of these types of support systems has been increasing steadily in underground coal mines.The development of this instrumentation has provided laboratory and field results that help to explain the mechanics and relationships between the applied loads and the interaction between the grouted bolt system consisting of the bolt tendon, grout, and rock."

Jan 1, 1990

By C. P. Moore, G. W. Taylor

Vertically dipping lenses of nickel-copper ore at Dumbarton Mines Limited are being mined by a modified blasthole stoping method. The principal access to the mine is provided by a 15-degree decline, which, in conjunction with the use of ramps and declines for secondary access, maximizes the accessibility and mobility of trackless mining equipment. Sublevels are driven in ore on 80-foot vertical intervals and subsequently the ore, ranging in thickness from 15 to 30 feet, is slashed to its limits by a procedure of face sampling and test holing. Two longhole drill jumbos are used to drill off 40-foot vertical slices above and below these levels. Following blasting, the ore falls by gravity to the 500-foot horizon, where it is removed from drawpoints by load-haul-dump units and transported by truck to the main orepass. The rock is crushed to minus 3-4 inches and conveyed to surface by a 30-inch-wide wire rope suspended conveyor. This is achieved in two flights, a lower one of 290 feet and a main flight of 2260 feet. All aspects of the mining operation are discussed in the paper, including ventilation, services and safety.

Jan 1, 1973

By T. D. Chatwin

Acid rock drainage (ARD) is one of the most serious and potentially enduring environmental problems of the mining industry. High liability costs carried by many mining companies to cover potential obligations of ARD are a clear indication of the gravity of the problem. Unchecked, ARD can result in water quality impacts that could well be the industry's most significant financial and credibility risk. Effectively preventing acid drainage is a formidable challenge that requires the total commitment of the mining industry throughout the entire life-cycle of a mine. To achieve this commitment a strong business case for ARD prevention must be developed. This paper will address the elements of acid prevention and discuss their importance not only to the company but the entire industry as well. The International Network for Acid Prevention (INAP) is an industry-led group created to help meet this challenge. In 2009, INAP published the GARD Guide (www.gardguide.com), a web-base best practices guide for the prevention of ARD [1]. In this paper, the GARD Guide will be used to identify preventative actions for all mining industry stakeholders. It will, in turn, be used to estimate ARD management and mitigation value accrued to the company from ARD prevention, which will be used in developing a business case for acid prevention.

Jan 1, 2011

By Fred A. Webber

STEEL ROPE WIRE is one of the more specialized commodities among the many grades of highcarbon steel wires. In its production there are many metallurgical aspects of interest from the steelmaking on through the final stages of wire drawing. We produce rope wire in an integrated mill com prising all the operations from the blast furnaces to finished wire drawing in the wire mills. Steelmaking is carried out with close control on hot metal, selection of scrap, and fluxing materials. The basic open hearths are of 170 tons capacity. Steel is teemed into 19 1/2 in by 19 1/2 in big-end-down molds and is hot-topped with the use of clay refractory hot-tops. The weight of this ingot is 6,900 pounds. All high -carbon steel ingots are charged hot into the soaking pits and are then rolled through the blooming mill in 16 p asses to a bloom ax~ in. by 41/2 in. and approximately 65 feet long. Necessary bottom and top crops are taken on the bloom as it passes from the blooming? mill to the billet mill. The still hot bloom is continuously rolled through the billet mill in . 5 passes to a 2 3/8 in. square. Billets are cut to 32 feet in length by a flying shear and then allowed to cool on the hot bed.

Jan 1, 1957

By J. W. McCammon

WHEN times are booming and metal prices are high, most mining men pay little attention to the industrial mineral industry. However, when metal prices drop and mines close down, many mining eyes begin to scan the less glamorous non-metallic field. For some this proves a temporary diversion, but others find this branch of mining, with its generally more stable conditions, to their liking and enter it permanently. The resulting gradual influx of trained mining men into the industrial mineral industry ?has been one of several factors responsible for the rise in production of non-metallic materials in our Province. Another and ?perhaps the most important factor influencing the production of industrial minerals has been the growth in the population of British Columbia. Because most industrial minerals .are low priced and either heavy or bulky commodities they are normally sold on relatively local markets. Thus the extent of the development of the industrial mineral industry of a region is largely governed by the size of the population and the level of industrialization of that region. This point is well shown by com-paring population and industrial mineral production statistics for 1936, 1946, and 1956 (see Figure 1)9. Note that not only has the overall production rate grown with the population increase, but that the per capita production has risen greatly.

Jan 1, 1958