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By K. Iturralde

The article discusses the possibility of automation in refurbishment processes of social dwelling built from 1950 to 1970. These massively produced buildings were mostly designed prior to the law enforcement regarding thermal insulation or accessibility. Nowadays, many of these buildings are being retrofitted. The article focuses on the works in the external envelope. The task of renewing the whole social building stock is big and it requires a systematic process that facilitates a rapid upgrading, without neglecting the specific situation of each case. How could an automatic refurbishment process of these buildings be defined? The process should start with the data collection of the building and the creation of a 3D model using software such as BIM. The project, drafted in 3D, should facilitate the manufacture of building elements by robotics. In turn, it should be noted that during the assembly at the site, the pieces must be fixed quickly and efficiently. Is it possible to implement an automated process for the refurbishment of apartments built in the second half of the twentieth century? To approach the answer, a virtual refurbishment project is performed. The article focuses on the rehabilitation of the building envelope. Furthermore, it gives special attention to the double skin facade. It is well known that a second skin in this type of building can be an element that integrates several functions. Finally, needless to say that refurbishment of residential buildings is a need in our society. By extending its life cycle, robotic refurbishment provides more favorable socioeconomic and environmental capabilities than the sole construction of new buildings.

Aug 1, 2013

By O. Moselhi

Material can be seen as the fuel needed to execute the project from inception to completion. Material installed provides good indicators of progress achieved onsite vis-a-vis project schedule performance. It correlates well with the role of the schedule performance index (SPI) of the earned value method (EVM). Material is recognized to have a significant impact on achieved progress for physical completion of project activities. This paper presents a study on the development of material status index (MSI) in support of the EVM. Unlike the SPI, the newly developed index account for the criticality of project activities. This is carried out considering the total float of each activity, percent float (i.e. the ratio of float to activity duration) and the total float of the path on which the activity is located. MSI, can independently and jointly with SPI provide root causes behind problems encountered during project execution. In turn MSI can reveal material related factors behind the performance detected by joint interpretation of the two indices. MSI serves to provide added value in alerting management to take corrective actions. While SPI and MSI may have different values, they can jointly augment and enrich the captured project status based on EVM. To demonstrate the capabilities of the developed MSI method, it is implemented on a case study. The case encompasses the construction schedule of a hydro power station constructed in northern Quebec. Different scenarios are adapted from the real case to demonstrate a set of practical aspects of the developed index. The results generated from the analysis of the case study illustrate the useful features of MSI beyond those of the traditional SPI on two fronts; causation and the considerations of criticalities of actives.

Aug 1, 2013

By Frank Martonhegyi

"The objective of this paper is to review the coal basins in the Canadian part of the Western Cordillera to aid their understanding, and to aid in finding and proving places of economic coal mining potential. Coal occurs in eugeosynclinal basins in the Western Cordillera which evolved through three stages: -from systems of volcanic arcs in the Late Jurassic to mid-Cretaceous; -through an intermediate stage with deposition in increasingly restricted successor basins in Jurassic to Early Tertiary; -to a continental stage by the Eocene. Minor coal seams occur usually in late volcanic arc stage sediments bur they can be locally thick as they are on Queen Charlotte Islands. Successor basins usually show a marine-paralic-limnic evolurion. Signijicanr coal deposits occur in the tarter two sequences in the Whirehorse (Tantalus) and Bowser (SkeenaSusrur) basins. Currenr activities are intensive in the more accessible Bowser Basin, for example at Telkwa, Susrut River and on the Groundhog coal field. On Vancouver Island major coal seams occur in cyclic sediments, but the more accessible deposits are mined our. Exploration renewed recently in the less accessible northern part of the Island, for example Quinsam, for surface mineable coal. The Western Cordillera is a mosaic of allochtonous tectonic blocks. They originated from the south and were displaced northward by several hundred kilometres. Many Tertiary coal basins are related to strikeslip transcurrent faults along which the later part of displacement took place, for example the Dawson coal area in the Tintina Trench. Tensional and dipslip normal faulting also created or enhanced sites for thick peat accumulation. For example at Hat Creek 280 m of coal occur in a 550 m section. Secondary structures are often better exploration targets than the main fault zones. Pluvial and alluvial fan environments away from the main drainage are usually the favourable sites for thicker and cleaner coal deposition."

Jan 1, 1985

By Eric D. Marks

Fatalities resulting from ground workers colliding with objects and construction equipment accounted for approximately 18% of the total construction fatalities experienced in 2010. Current injury and fatality measuring methods have proven to be inadequate due to their use of passive measures of safety rather than a more active approach, such as the use of leading indicator data (also called near misses) of hazardous proximity situations between ground workers and heavy equipment on construction sites. The objectives are to create and evaluate the effectiveness of a reliable algorithm for collecting and analyzing the resulting leading indicator data from hazardous proximity situations. Numerous experiments emulating typical interactions between workers-on-foot and heavy equipment are used to evaluate the proximity sensing and detection technology. Safety leading indicator data (also called near misses) generated by the proximity sensing and detection technology during the experimental trials are used to create and assess the resulting algorithm. Results from the experiments indicate that leading indicator data generated from these systems can be processed and analyzed to identify hazardous proximity situations and incidents on construction sites.

Aug 1, 2013

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 Troy Boisjoli

Since its discovery in February 2014, the Arrow Uranium Deposit has undergone rapid development through aggressive and systematic drilling programs and is now being progressed through advanced engineering and permitting. Based on the 2018 NI 43-101 Technical Report, the Probable Mineral Reserve estimate totals 234.1 million (“M”) pounds (“lbs”) triuranium octoxide (“U3O8”), contained in 3.43 M tonnes at an average grade of 3.09% U3O8. The proposed processing plant at the Rook I Project (the “Project”) will be capable of producing up to 31 M lbs of U3O8 per year, with a projected mine life of nine years based on the Probable Mineral Reserve estimate, although NexGen is permitting a 24-year operating life at the Project assuming the majority of Inferred Mineral Resources are upgraded to Indicated Mineral Resources with continued mineral resource development drilling. The Project will be developed through transverse and longitudinal longhole mining methods, pairing primary and secondary stoping techniques with a high degree of equipment mechanization which will provide a combination of good productivity, high extraction, and stable back support. This next generation of uranium operations combines the use of advanced tele-remote equipment and instrumentation with a low-cost bulk mining method and a best-in-class tailings management practice, effectively reducing operating costs and setting a new standard for elite environmental and social practices.

Jan 1, 2020

By K. Iturralde

Dense transport infrastructure areas lack green facilities, they produce annoying noise and they are big energy consumers. As far as there is no free land or space, adding a vegetal covering to existing infrastructures has become a choice in order to get a more pleasant and comfortable environment. Noise barriers are getting spread all over the highways and sometimes they install photovoltaic panels. Is this just a hype or are there real causes? A green acoustic barrier with an energy generator could be interesting for covering the existing urban transport infrastructures. The specific geometry of the infrastructures requires a personalized product. If we measure the infrastructure environment's characteristics, which are humidity, temperature, sunlight and size, we can create an accurate 3D model. This model would be used for various purposes. For instance, it could be a useful tool to design and fabricate the customized prefab acoustic barriers and plant containers. And it would be helpful for adjusting efficiently the future performance of the vegetation and photovoltaic panels. But the insertion of vegetal elements in infrastructure surroundings can be a tough operation. It requires special skills and techniques. Nowadays, those tasks are performed almost manually and they require a big effort. The prefab containers for vegetal elements would ease the robotic assembly on site.

Aug 1, 2013

By Ali Hashemi, Anna P. Perry

The PQ Deeps (PQD) is a production zone located at Newmont’s Musselwhite Mine in northern Ontario. Development started for the PQD in late 2017, and the first stopes were mined starting in early 2021. Unlike most historic longitudinal stoping of narrower orebodies at Musselwhite, the PQD is a wider orebody following the plunge of a fold hinge and is extracted primarily by transverse stoping. Some geotechnical challenges were experienced during early stoping efforts, necessitating design changes throughout late 2021 and early 2022 to optimize the stope design. This work describes the mining methods and design changes to transverse PQD stoping based on geotechnical lessons learned during early stoping efforts.

Jan 1, 2023

By D. B. Johnson

Acidic, metal-rich waters generated at working metal mines and abandoned mine sites are generally considered to be major pollutants of the environment. However, the metals they contain often have significant value of their own, or as sources of useful mineral products. We have developed novel bioreactor systems that facilitate the selective recovery of various transition metals (e.g. copper, zinc and iron) as defined minerals that can be recovered and recycled. The bioreactors use novel species of acidophilic bacteria. Ferrous iron is oxidised by Ferrovum myxofaciens, a specialist bacterium that forms large amounts of exopolymers and grows as filamentous streamers in flowing mine waters, and the ferric iron generated is precipitated as the mineral schwertmannite, a small proportion of which is used to remove any arsenic present in mine water. Copper and zinc are precipitated as sulphides using H2S generated by consortia of acidophilic and acid-tolerant sulphate-reducing bacteria in a continuous flow, on-line low pH bioreactor. Transition metal sulfides can be segregated by precipitating them, either on-line or off-line, at different pH values. The modular units that have been developed can be configured to treat mine waters of different chemistries. A hypothetical acidic (pH 2.5) mine water stream containing 500 mg/L iron, 100 mg/L of copper and zinc, 50 mg/L of aluminum and manganese, 2 mg/L of arsenate, and discharged at a rate of 10 L/s, is used as an example of the potential application of the mineral-generating bioreactors. The environmental benefits and economic implications of considering mine waters as resources rather than wastes are discussed.

Aug 1, 2013

By Carmen M. Neculita

Optimizing the long-term efficiency of passive systems for the treatment of highly contaminated acid mine drainage (AMD) is still a challenging issue. The optimization lies, among others, on improving the understanding and quantification of metal removal mechanisms in order to predict and enhance the stability of neo-formed minerals in secondary phases. Sorption, and precipitation as oxides-hydroxides, carbonates and bio-sulfides are likely the most important metal removal mechanisms involved in passive biotreatment of both slightly and highly contaminated AMD. In the same time, the preferred mechanism is precipitation of metal sulfides that are more stable and less pH dependent than carbonates and oxides-hydroxides. However, results of relatively recent research studies performed at laboratory scale showed that sulfides accounted only for up to 15% of total metals removed in passive bioreactors treating highly contaminated AMD dominated by iron (around 500 mg/L). Several approaches were used in the aforementioned studies to understand and quantify metal removal mechanisms in spent reactive mixtures collected from long-term (12-15 months) operating column bioreactors. These included: thermodynamic equilibrium modeling and various chemical extractions and mineralogical analyses (such as single and sequential extractions, acid volatile sulfides-simultaneously extracted metals determination, scanning electron microscopy, X-ray diffraction, and thermo-gravimetric analysis). The large proportion of metals (85%) removed by sorption and precipitation as oxides-hydroxides and carbonates suggests a relatively high mobility of the neoformed minerals, especially in low pH conditions. However, no data is available on the long-term stability of spent reactive mixtures and, on the implications for the sustainable management of this type of solid waste. Lately there is almost a consensus that the efficiency of highly contaminated AMD treatment is warranted by the use of multi-step passive systems, including both chemical and biological units, installed sequentially. However, very few well-documented studies are available on the design, construction, operation and long-term efficiency of these multi-step systems. A leading example is the tri-unit passive system installed on the abandoned Lorraine mine site (Québec) to treat a highly contaminated AMD dominated by iron (about 2,500 mg/L). This tri-step system (160 m3), consisting in two bioreactors separated by a unit filled with wood ashes, achieves to date a satisfactory removal of iron (up to 99%). Moreover, based on the data collected during laboratory testing, iron was mainly removed in the wood ashes unit (from around 3,200 mg/L to 10 mg/L) by precipitation of oxides-hydroxides as predominant mechanism and only partially by sorption. However, no data is available on the actual metal removal mechanisms in the field. Overall, theses multi-step systems are more complex and their long-term performance is even less predictable than the single unit systems. This paper presents the current knowledge and the research needs on metal removal mechanisms in passive bioreactors and multi-step systems for the long-term treatment of highly contaminated AMD. KEYWORDS

Aug 1, 2013

"Line Creek Resources Ltd. produces three million clean tonnes per year of metallurgical and thermal coals for the international market. The mining operation, which is located in the mountains of southeastern British Columbia, produces coal from four pits by conventional truck and shovel methods.The South Pit, which has been in operation since J982, has a benched highwall 490 m in height. Shallow dipping coal seams at the base of the syncline formation will be exposed in the highwall over the next four years of pit life. The first of these seams, which will measure 500 m in final highwall length, was exposed in J994. An auger, powered by a 1250 hp engine capable of cutting 2.2 m diameter holes, was brought on site in J994 and has proven to be a successful means of recovering coal from the J3 m thick seam.This paper covers the background to the selection of an auger mining method to recover highwall reserves together with the geotechnical and methane considerations for this approach.IntroductionLine Creek Resources Ltd., a wholly owned subsidiary of Manalta Coal Ltd., owns and operates the Line Creek mine. The operation which consists of four active pits, a processing plant, and rail loadout is located in the southeastern coal fields of British Columbia. Figure 1 shows the general area.The coal bearing sequence at the mine is preserved on the east and west limbs of a major syncline. Up to twelve mineable coal seams, ranging in thickness from 2 m to 15 m are contained in the formation. Within the pits the seams are stratigraphically consistent and structurally undisturbed, except for small-scale thrust faults that create multiple repeats of the seams."

Jan 1, 1995

By Samuel Frimpong

Green house gases have become a major concern within the international community over the last two decades due to their potential link to global warming. Carbon dioxide (CO2) is the principal greenhouse gas. In the Kyoto Agreement, Canada has committed to reduce emissions by 6 % below 1990 levels by 2012. This presents a serious economic challenge to Canada and Alberta. Over the next decade, oil sands production expansion, population and industry growth and energy demand will increase CO2 emissions. Current and future CO2 emissions and their economic implications in Alberta will be critical in formulating a comprehensive and balanced policy for dealing with concerns in this area. Disposal of carbon dioxide (CO2) in land aquifers is a potentially viable option for Alberta in dealing with long-term CO2 emissions. Studies have confirmed the existence of appropriate aquifers in the Alberta Basin for CO2 storage over a long geological period. Carbon dioxide is an ideal candidate for aquifer disposal because of its high density and solubility in water at relatively high pressures. In this study, the authors develop a computer simulation model of a scaled aquifer disposal system. The scaled model consists of an injector well, aquifer environment with dominant Ca++ and Mg++ cations. Liquefied CO2 is injected at an appropriate pressure and concentration through an injector well model. The injected CO2 migrates from the point of contact between the injector well and the aquifer domain to the main regime of the latter. The rate of migration is a function of porosity, permeability, cations, aquifer fluid flow regime and CO2 injected pressure. These models are validated using flue gas data from the 546 MW Wabamum Power Plant in Alberta. The total energy requirements for aquifer CO2 disposal system are distributed between a minimum of 105 MW and a maximum of 172 MW, with a mean of 132 MW and a coefficient of variation of 10%. The results show that there is significant variability in all the energy requirements for the CO2 disposal system. The total energy requirements for the disposal system as a fraction of the total power generated by the Wabamum plant of 546 MW could be between 0.19 and 0.32. This is a very significant energy requirement and thorough analysis must be carried out to reduce this variability and energy requirements.

May 1, 2001

By E. Essadiqi, P. Poruks, D. Boyd, D. Emadi, I. Yakubtsov, T. Turi

This paper reviews the results of an extensive study of microstructures and mechanical properties in bainitic linepipe steels. The research was carried out as a collaborative project between Queen's, Stelco and CANMET. Basic studies of phase transformations and mechanical properties in these steels established important relationships between processing schedule and microstructure evolution, and between final microstructure and mechanical properties. The best combination of strength and toughness properties is obtained with a microstructure comprising a matrix of intragranularly-nucleated bainite (`acicular ferrite - AF') and small (~ 0.5 µm) dispersed particles of martensite (`M/A'). We describe this as a dual-phase AF+M/A microstructure. An experimental study on 15-mm thick plate determined the window of steel composition and processing parameters which gives the dual phase AF+M/A microstructure. The minimum strength and toughness properties for Grade 621 (X90) linepipe steel can be achieved by either a lean steel composition (0.04C-1.77Mn-0.04Cr¬0.32Mo-0.31Ni-0.29Cu-0.08Nb) with extreme processing parameters, or by a higher alloy composition (0.04C-2.07Mn-0.50Cr-0.51Mo-0.04Nb) with a more industrially realistic processing schedule. It is proposed how this approach could be extended to obtain higher strength linepipe grades.

Jan 1, 2005

By Richard Wells

Peabody Energy is the largest pure-play publicly traded coal company in the world. We have been in business 129 years and like most of the coal mining companies in the United States, since 1969 the majority of our safety improvement efforts had been driven by compliance with the various versions of the Federal Mine Safety and Health Act and the supporting federal regulations. In 2004 Peabody Energy management came to the understanding that in order to achieve our goal of zero incidents, that focus must change. This paper will describe the elements of the journey we began at that point to make the transition to a behavior and systems-based approach to safety management and our efforts to win the minds and hearts of our employees. This journey is undertaken with the goal of making safety truly a way of life for all Peabody Energy employees.

Aug 1, 2013

By J. Qi

Based on the commercial steel 42CrMo (4140, SCM440), a new generation of CrMo steel was developed by increasing the content of Mo, adding the alloy element of V and Nb, and decreasing the content of P and S. This new CrMo steel has higher strength of 1500MPa and better delayed failure property. TEM and EDS were used to study the distribution and function of the alloying elements in this steel. A new EELS technique was developed to study the bonding strength of the grain boundary in the steel. The mechanism of strengthening of the new steel has been studied.

Jan 1, 2004

By Jean-François Lagueux

Goldex Mine is an underground mine located near the town of Val-d?Or. Multiple innovations were required to work the mine. Due to its low grade, it was important to develop a bulk mining method to economically extract the ore. The method used is a combination between shrinkage stope and long hole stope methods. This modified method is more than adequate; however, all of the ore body must be liberated in a very short period of time. Therefore, to bring down 23 Mt of ore, large blasts up to 1.8 Mt are required. The situation is also complicated by the fact that the mine is located in a residential area. No less that 40 homes are built within a 1 km radius of the mine site. In addition to managing mass blasts, means must also be found to mitigate the vibrations produced by the blast to diminish the disturbance to the neighbourhood. Therefore, the mine used numerous tools to properly plan the blasts and reduce the impacts. A program to control vibrations was one of the first tools put in place. The program?s aim was to draw up an action plan to ensure a follow-up of the homes by inspecting them. The second tool was to develop a methodology to plot a reliable attenuation curve and to adequately determine the maximum charge weight for each blast. Finally, effective communication tools were developed to inform the neighbourhood. There was a huge amount of work to be done in relation to the bench. Reliable and fast loading techniques had to be found to load large blasts in a very short period of time. Adequate logistics had to be developed to send underground more than 20,000 kg of emulsion per day while performing the daily underground operations. Technology had to be developed to adapt the i-kon electronic blasting system to large blasts. Since the control of the charges was the major factor to reduce surface vibrations, it was important to employ loading techniques that would permit decking of the long holes to reduce the charge weight per delays without adversely affecting the loading. All of this work requires an enormous amount of energy but also close collaboration between the different stakeholders (various departments, suppliers and consultants).

May 1, 2011

By Les F. Sawatsky

Surface drainage, particularly mine closure drainage, must be properly considered during all stages of mine planning because it presents constraints that are critical to economic mine operation, minimizing environmental impacts and ensuring compliance with government regulations. Deficient mine site drainage increases costs of operation, causes unnecessary environmental impacts and may result in regulatory violations. The scope of this paper includes stream diversions around mine areas, drainage systems within the mine disturbed footprint, and closure drainage works to control surface water, ground water, erosion, sedimentation, and seepage discharges following mine operations. Developing selfsustaining drainage facilities upon mine closure, requires a mine plan that develops appropriate topography and constructed drainage courses that replace the function of pre-disturbance drainage systems without aggravated erosion and deterioration. Drainage criteria, particularly closure drainage criteria, represent important constraints on mine planning and are best considered by integrating drainage features into the mine plan well in advance of mining activities. Integrated mine planning by a multi-disciplinary team is recommended to achieve closure objectives at minimum cost and maximum effectiveness The geomorphic approach to channel design is an effective means of providing a drainage system that has the appearance, function and longevity of natural systems. By incorporating this technique into closure drainage planning, mine operators can construct sustainable (walk-away) drainage systems that require little or no maintenance in the long-term. This paper presents a process by which drainage criteria and associated mine plan constraints can be integrated into the mine planning process. This paper outlines the process for detailed design of drainage facilities, particularly closure drainage systems that are designed by the geomorphic approach.

May 1, 2009

By D. Pérez Escobar

Multiphase steels are quite sensitive to hydrogen embrittlement. Laboratory tests to evaluate this often use electrochemical, charging to introduce hydrogen into the sample, but damage purely caused by hydrogen charging has to be avoided. A ferrite-bainite steel, was charged using various conditions to identify when surface blisters occurred. Samples were also checked for internal, damage by electron microscopy. This study was repeated for three other multiphase steels and pure iron. An HSLA steel, was found to be more resistant whereas pure iron was quite susceptible to internal, hydrogen damage. For al, industrial, steels, cracks concentrated in the middle of the sample were attributed to inclusions and segregations, inherent to production.

Jan 1, 2010

By C. Groccia

As the search for new ore bodies drives mines to be developed at greater depths, the associated high stress environments present challenges for rock support design. Excavations in highly stressed brittle rock are often subject to large volume increases due to rock failure, a phenomenon known as rock mass bulking, which can result in significant wall convergence. Support systems need to be designed to minimize the amount of bulking and to accommodate large wall convergences. In order to design such a support system, empirical guidelines are often used to predict the amount of bulking. However, the empirical guidelines that are currently available are based on a limited number of case studies and consider few input parameters, which may result in an inaccurate bulking assessment. This paper describes methods of collecting quantitative field data at Creighton mine in Canada to better understand rock mass bulking and to further develop the empirical guidelines for bulking assessment for tunnels in highly stressed grounds. Measuring

Aug 1, 2013

By P. J. Mackey, Elsie Kossatz

The small town of Bruce Mines lies a few miles east of Sault Ste. Marie, Ontario on the north shore of Lake Huron. This was the site of the first copper mine. This copper smelter used a reverberatory furnace, based on the Welsh process, and operated in the period of 1849 to 1850, when the plant was destroyed by fire. During the period of 1850 to about 1869, crushed and sorted ore was shipped to England and later to the United States. In 1869, a roastleach plant, based on the Henderson Process, was constructed at Bruce Mines and was operated until about 1872. This short article describes the early development of this historic operation. Although the rich copper ore found in the vicinity of Bruce Mines was known to the Indians, its discovery in or about 184 7 was credited to Mr. Keating, who named the area Bruce in honour of Lord Elgin (James Bruce), Canada's Governor General. In 1848, the property was acquired by the Montreal Mining Company for 40 000 pounds sterling and the company immediately sent a small party to investigate the deposit. The party sank a shaft on a lode within a hundred yards of the lake and also reported two adjacent lodes farther inland, which were left undeveloped until the turn of the century. Initially, the foundation of the headframe and hoist was built above the frost line and when the machinery was set in motion it collapsed. Eventually, the shaft was to reach a depth of 300 feet. By 1849, the property was well established and the small settlement consisted of 77 miners, 65 labourers, 4 boys, 11 tradesmen, including blacksmiths and carpenters, 2 mining captains, 1 engineer, 2 clerks and 1 superintendent. The community, including the workers' families, numbered about 250.

Jan 1, 1999