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By H. Clare Horwood

"Three types of structures, the main shear zone, the north shear zone, and a series of hanging-wall fractures, contain all the orebodies so far discovered at the McKenzie Red Lake mine. Lenses and veins of quartz in these zones and fractures are the sources of the ore. The ore-bearing structures are unusual in that they are in a complex intrusive mass known as the McKenzie-Gold Eagle stock. They are believed to have been produced by compressive stresses from the south andsouthwest.The mine is on the northeast side of McKenzie island, in Dome township in the central part of the Red Lake area. The original discovery, the main shear zone, was made in 1928, about 3 years after the property was staked, by M. L. Bouzan who was in charge of prospecting and development work on the property. Subsequent diamond drilling and underground exploration led to the installation of a mill, which came into production early in 1935. The hanging-wall fractures were found branching out from the main shear zone during development work on the 350-foot level. The north shear zone was discovered in 1940.From 1935 when the mill began operation until the end of 1946 total production from the mine was approximately 269,349 oz. gold and 69,317 oz. silver, having a value of $9,679,739, recovered from 823,527 tons of ore.GENERAL GEOLOGYThe McKenzie-Gold Eagle stock has a total length of approximately 1 ½ miles and a width of about ½ mile. It was intruded into a complex synclinal fold in Timiskaming sediments. The sediments, which have been cut in only one place in the underground workings, are principally wellbedded greywackes. The stock is composed of large masses of diorite and granodiorite, a small mass of hornblende pyroxenite, and basic dykes of two ages. The diorite occurs as irregular masses in large measure surrounded by the granodiorite that it intrudes. It contains tabular crystals of andesine, having a maximum length of3/4 inch. The hornblende pyroxenite is an elongated lens or dyke in the diorite. The granodiorite masses occupy about two-thirds of the stock. Along its eastern side the main mass tends to become darker and more dioritic toward the diorite contact.Basic dykes of pre-vein and post-vein age are the youngest intrusive rocks at the mine."

Jan 1, 1954

By J. G. Peacey

"Canada has a special place in non-ferrous pyrometallurgy because it is the only country in the western world that is a significant producer of all the major non-ferrous metals; aluminum, copper, lead, magnesium, nickel and zinc. This large non-ferrous pyrometallurgy industry has developed because of Canada's abundant mineral wealth and energy resources. Table I summarizes the number of primary non-ferrous production facilities in Canada and their share of western world production.Production of non-ferrous metals is a mature, capital intensive business and its basic processes have been in use for many years. Nevertheless, these processes have continued to evolve in response to changing needs and external pressures; such as the energy crisis of the early seventies; historically low metal prices in the early eighties and the continuing pressure to reduce plant emissions and improve in-plant working conditions. Canada's major metallurgical companies: Alcan, Cominco, Falconbridge, Inco and Noranda have played a leading role in pioneering new process technology and continue to meet the difficult challenge of keeping their operations competitive in the global metals market. This paper will try to give an overview of the major developments in non-ferrous pyrometallurgy, largely from the Noranda and Canadian perspectives, highlighting the current status of process technology and possible future directions.AluminumCanada has the world's second largest aluminum smelting industry and its capacity has expanded rapidly in recent years with the completion of several large projects in Quebec. The location and capacity of the Canadian aluminum smelters are given in Table 2. All these plants use the Hall-Heroult process, that was invented over a century ago but over the last twenty years considerable improvements have been made to increase productivity, reduce power requirements and emissions.The developments in aluminum cell technology can be illustrated by the experience at Noranda Aluminum. In 1971, Noranda Aluminum started its first pot line using Kaiser's P69 prebake cell, which was considered, at that time, the best available technology. The P69 cell was designed primarily for high productivity, operating at 150 000 amps and high current density to produce just over tonne Al per cell-day. The P69 cell is a simple design, typically operating at about 88070 current efficiency and 15 800 kWh/tonne Al. When Noranda Aluminum decided to expand in 1980, the Alcoa 697 cell was selected as it then represented the most proven, stateof- the-art technology. This cell is similar to that installed at Alcan's new Grande Baie and Laterriere smelters and is designed to operate at 180000 amps and 93070 current efficiency, producing about 25070 more aluminum per pot-day than the P69 cell using about 15070 less power. The 697 cell has a much more sophisticated cell design, with very good balancing of the magnetic field giving a flat metal pad and allowing efficient operation at the higher amperage. Alumina is fed via point feeders that provide an almost continuous feed allowing close control of the alumina level in the bath and the use of low-ratio bath composition, giving much higher current efficiencies."

Jan 1, 1991

By A. Perucho, J. P. Harrison, A. Bedi, L. Alejano, L. Lamas, A. Sofianos, A. M. Ferrero, R. Migliazza, R. Olsson, J-F. Mathier

"In 2010, the Eurocode for Geotechnical Design, EN-1997-1:2004 (CEN, 2004), informally known as Eurocode 7 or EC7, became the Reference Design Code (RDC) for geotechnical design – including rock engineering design – within the European Union (EU). EC7 is one standard within the comprehensive Structural Eurocode suite, which as a whole has been also adopted by a number of other countries beyond the EU. EC7 is thus becoming a key design standard for geotechnical engineering worldwide.As part of the Structural Eurocode suite, EC7 requires designs to adhere to the principles of Limit State Design. However, it is not clear that current rock engineering design practice can satisfy this requirement. In addition, evidence is accumulating that EC7 is currently difficult to apply to, and may even be inappropriate for, rock engineering design. These issues may be due to the fact that the development of EC7 to date took place without any formal input from the international rock mechanics and rock engineering community.In early 2011 under the auspices of CEN (Comité Européen de Normalisation / European Committee for Standardisation), EC7 entered a formal period of maintenance which was aimed at improving the applicability and ease-of-use of the Code. This maintenance cycle will conclude in 2020 with the publication of a revised version of EC7.This paper describes a number of critical aspects for rock engineering in the context of EC7, inparticular the following:– the history of the Structural Eurocodes and the concepts they embody;– the nature of Limit State Design and the challenges and opportunities it poses for rock engineering design;– the formal means by which the Structural Eurocode maintenance cycle proceeds;– the plans currently being developed for improving EC7 with regard to rock engineering design and construction;– the unique and vital opportunity for the entire international rock mechanics and rock engineering community to comment on the Code and make suggestions for its improvement."

Jan 1, 2015

By A. Vervoort

The concepts of geostatistics are commonly difficult to understand for students, even for those with a strong mathematical background. A main problem is certainly the link between the variation of the parameter value in space or time, and the calculated experimental semivariogram as a function of the interdistance, but over the entire area. Another problem is to differentiate between directional and omnidirectional semivariograms and the way they have to be interpreted. Furthermore first time users of geostatistics often do not want to struggle through different books with the whole geostatistical background before using it. Too often this leads to using geostatistics as a black box with all the risks linked to it. That is the main reason that we developed some interactive tools based on the free public domain software R. We aim by developing three different modules to assist individual first time users, but also regular students and teachers to get a feeling of the importance of the various aspects in conducting a good geostatistical study. The modules show directly e.g. the impact of deleting, moving or adding data points, of changing parameters of the semivariogram model and of the geometrical parameters during kriging. The first module allows making the link between the variation of the parameter values in one direction and the calculated experimental semivariogram, and this for different given datasets. The second module covers two dimensional datasets and apart from calculating the semivariogram values, models can be fitted to the calculated data. A distinction can be made between omni-directional and directional semivariograms, including the effect of the tolerance on the angle and lag-distance. The third module focuses on ordinary kriging of point values in two dimensions. The aim of the interactive tools developed is limited to educational purposes only, i.e. to visualize some basic concepts for different pre-selected types of spatial variation. They do not intend to do a geostatistical study on a certain dataset (for this purpose there exists already a broad spectrum of good software packages). The original intention of developing the three modules was aimed at users with no or a limited amount of geostatistical experience. However, these modules seem also very useful to remain critical for experienced users. One should never forget that in a real application one does not have a complete view of the phenomenon studied. The geostatistical interactive modules can be accessed through: www.bwk.kuleuven.be/geostatistics . We compiled a manual to facilitate the use of the modules and to guide the user we formulated several questions to be solved for each module.

Aug 1, 2013

By J. D. Stewart

One of the first important questions that should be settled on the opening of a mine or the development of a new deep is the system of haulage to be used, since the layout of the haulage-ways at the pit bottom, or, in case of a slope mine, the arrangement of the surface works, depends largely upon the type selected. Should it later become desirable to install a system of haulage of a type other than that for which the mine roadways were originally laid out, considerable difficulty would likely be encountered in its installation and with the result that it would in all probability be most unsatisfactory and expensive in its operations. It therefore becomes very necessary that full consideration be given the haulage problem at an early date in order that the type best suited to the mine conditions and the required outputs can be intelligently planned for. It is sometimes found, however, that no matter how well the mining engineer explores the seam to be developed, or how accurately he anticipates its eccentricities, there will still remain some unrevealed or unsuspected conditions, or shall we say obstacles, placed by Nature to prevent the too easy winning of her treasures and incidentally to frustrate or modify the application of the plan so painstakingly laid down on paper, and to adversely affect the cost estimate.

Jan 1, 1928

By Patty Simpson, Sarah Benson

In an effort to improve consistency across the nuclear industry, over the past 10 years the Canadian Standards Association has developed a series of standards related to environmental management at Class 1 nuclear facilities and uranium mines and mills. Canadian uranium mines have been required by the Canadian Nuclear Safety Commission to align their existing monitoring programs with these standards. Orano’s McClean Lake Operation’s monitoring program, which was originally presented in the Environmental Impact Statement in 1991, has evolved through regulatory change, new scientific understanding, additional projects, and experience into a comprehensive set of monitoring requirements for effluent, groundwater, air emissions, and the receiving environment. The exercise of aligning the existing practices with the standards provided an opportunity to review and rationalize the entire program. To document the process the original “Environmental Monitoring Program Design Document” was restructured and developed as both a repository for historical information and monitoring rationalization, and also to be a living document describing on-going studies and supplementary work that are outside of the regular environmental monitoring program and may justify future changes to the program.

Jan 1, 2020

Inco Limited has been evaluating options for streamlining the overall flowsheet at its Sudbury, Ontario operations to improve productivity and to minimize the cost of at¬mospheric emissions reduction. Some of the flowsheets being considered include vari¬ous levels of copper/nickel separation at the Clarabelle Mill where all Inco's Sudbury Basin ores are processed. This paper reports on the laboratory and miniplant studies car¬ried out during the flowsheet development for a commercial Cu/Ni separation plant. There are two potential feed streams for Cu/Ni separation. It was determined that Cu/Ni separation from the rougher concentrate requires no regrind, and a very clean copper concentrate is produced, but the recovery of copper is limited to about 70% from ore. Cu/Ni separation is more difficult from the bulk concentrate because of the presence of excess flotation reagents in the slurry and due to locked particles. By replacing the slurry water with clean process water, and by addition of some hydrogen peroxide, entrainment is minimized and excess reagents are removed from the surface, providing a satisfactory separation of copper from nickel. Fine regrinding is required to increase liberation of the locked particles and to obtain 85% copper recovery with minimal nickel contamination of the concentrate.

Jan 1, 2005

By N. T. Avard

THE Joggins coal field, Cumberland county, Nova Scotia, is on the easterly side of Chignecto bay, at the head of the bay of Fundy. In area, so far as proven, the field extends easterly from the town of Joggins about fifteen miles to Chignecto. The distance across the outcrops of the several seams exposed is approximately one mile. HISTORY Early records of coal mining in this locality are somewhat obscure, but it is known that prior to 1750 the French settlers were mining coal for their own use from the seams which outcrop in the floor of the bay adjacent to the shore, where, at low tide, the reefs are bared for a mile or more. Coal was also mined from the seams outcropping in the cliffs. It is known, too, that at Joggins coal has been mined commercially for over one hundred years. At first, all shipments were made by water, but in 1882 a railway connecting with the Intercolonial railway at Maccan was built to serve this field. GEOLOGY Due to the abundance of fossils in the strata forming the Joggins cliffs, this area was for many years a mecca for geological students from all over this continent. A 'sunken fcrest' in the shoreline was of particular interest but, due to constant erosion by the sea, this has apparently been all washed away. On the Joggins shore, the cliffs stand sixty to one hundred feet high, and six workable coal seams, with numerous smaller ones, are there exposed. Others outcrop in the reefs extending from the shore toward the bed of the bay. In working underground, fossilized trees are often found immediately overlying a coal seam, and standing at right angles to the pitch of the seam. This is said to be an unusual condition. In most cases, the bark of the tree is a fine-quality coal, with high carbon content, whereas the pulp has turned to 'stone'. There is a definite tendency for the coal to run out, or turn to shale. One seam, workable two miles from the shore, has almost completely disappeared in the outcrop at the shoreline. ? It was thought that a large area could be mined under the bay from an opening near the shore, but the first submarine level had to be abandoned at a distance of 4,000 feet, where the coal became very dirty and shaly, and the mine able area to the westward became more restricted as the mine was developed to the deep. This tendency is common to all seams.

Jan 1, 1944

By W. P. Nash, T. E. Mccandless

"Abstract - Detrital minerals of upper mantle origin occur in Holocene conglomerates, pediments and antmounds, and in Oligocene conglomerates in the Green River Basin of southwestern Wyoming. The minerals are derived from disaggregated eclogite and peridotite, and are similar to minerals found in mantle- derived igneous rocks such as kimberlite and lamproite, the primary host rocks for diamond. The Green River Basin bisects the lamproite fields of the Leucite Hills (Wyoming) and Kamas (Utah) and overlies the Archean Wyoming craton, which makes the region favorable for diamond occurrence. Lamproite is the favored host for the indicator minerals because unusual high-Fe salitic diopside macrocrysts from the antmounds and from the ~1 Ma old Leucite Hills lamproites to the northeast are compositionally identical. The salitic diopside is uncommon in other igneous rocks and could be a new indicator mineral for use in lamproite exploration. The Green River Basin indicator minerals are eroded from the ~29 Ma old Bishop Conglomerate, whose source area is the Uinta Mountains to the south. No continuous mineral train exists between the Uinta occurrences and those in the Green River Basin. Assessment of the minerals using established and new geochemical criteria indicate that they formed in an oxidizing upper mantle and were transported to the surface by either kimberlite or lamproite. The existence of cogenetic diamond is unlikely based on the mineral chemistry, but selective removal of diamond indicator minerals through weathering and fluvial transport cannot be excluded. Diamonds and mantle garnets are present in the northeastern Uinta Mountains, but they originated as part of the Diamond Hoax of 1872. A representative mineral assemblage from the true igneous host of the indicator minerals is required to fully establish their economic potential. Post-Oligocene erosion and Pleistocene glaciation have hindered efforts to locate a bona fide igneous source for the indicator minerals. Résumé - Des minéraux détritiques provenant du manteau supérieur ont été trouvés dans des conglomérats, des pédiments et des monticules de fourmis de l’Holocéne, et dans des conglomérats de l’Oligocène du Green River Basin, au sud-ouest du Wyoming. Ces minéraux sont issus du démantellement d’éclogites et de péridotites, et sont semblables aux minéraux trouvés dans des roches ignées provenant du manteau, comme les kimberlites et les lamproïtes. Ces dernières sont les roches hôtes du diamant. Le Green River Basin recoupe les champs à lamproïte de Leucite Hills, au Wyoming et de Kamas en Utah, et il surmonte le craton archéen du Wyoming, connu pour la présence de ses diamants. La lamproïte est l’encaissant privilégié pour les minéraux «indicateurs» parce que des macrocristaux exceptionnels de diopsides salitiques riches en Fer, provenant des monticules de fourmis et des lamproïtes de Leucite Hill (~1 Ma), au nord-est, ont des compositions identiques. Le diopside salitique est rare dans les autres roches ignées et peut être un nouvel indicateur dans la recherche de lamproïte. Les minéraux «indicateurs» du Green River Basin proviennent de l’érosion du Conglomérat de Bishop, daté de ~29 Ma, dont la zone source est représentée par les Uinta Mountains, au sud. Aucune continuité des gisements minéraux n’existe entre les affleurements de Uinta et ceux du Green River Basin. La détermination des minéraux, utilisant des critères géochimiques anciens et récents, indique qu’ils se sont formés dans un manteau supérieur oxydant et qu’ils ont été remontés à la surface soit dans des kimberlites, soit dans des lamproïtes. La genèse du diamant n’est que peu liée à la chimie minérale, mais le lessivage d’indicateurs minéraux du diamant par altération météorique et par transport fluviatile ne peut être exclu. Des diamants et des grenats mantelliques sont présents dans le nord-est des Uinta Mountains, mais sont associés avec le Diamant Hoax de 1872. Un assemblage minéral représentati"

Jan 1, 1996

By Szilvia Szabo, Jozsef Paulovics, Ljudmilla Bokanyi

"Waste recycling is one of the most important challenges of the XXI century. The recycling of wastes is closely related to and bases on the mineral processing. Many mineral processing techniques and equipment are applied in this field. The principles of the characterisation of wastes and design of technologies is rather similar to the classic mineral processing. Nevertheless, the diversity of the wastes and their complex composition and properties, as well as their environmental impact requires a special approach.Solar elements have sandwich structure of glass substrate and cover, as well as a very thin semiconductor layer. CdTe semi-conductor can be recycled by flotation. Within the RESOLVED (LIFE European Framework) R&D project on the recycling of solar elements the surface properties of pure CdTe semiconductor and pure glass were investigated by the measurements of zeta-potential using Zeta PALS Brookhaven instrument at University of Miskolc. Applied surfactants were: potassium ethyl xanthate; the anionic oxhydryl Aero Promoter 825 or Flotinor SM 35; the cationic Armoflote 43 or Armoflote 64, as well as Hostaflot LET (dithiophosphoric acid diethyl ester) and Hostaflot M91 (mercaptobenothiazole). The tested electrolyte was sodium-silicate. Zeta-measurements were carried out in full pH-range. Interfacial interactions were detected and interpreted. The basic results were verified by the flotation kinetic tests.Finally, the flotation technological experiments were carried out at a semi-technical scale using the real obsolete solar elements. The particle size at the liberation degree of 98% was as fine as below 5 µm. A special flotation cell providing the generation and distribution of very fine air bubbles was built. The pre-concentrate for the manufacturing of the test solar module was performed and transported to the BAM Institute (Berlin), the principal co-ordinator of the Project, and then further to the First Solar (USA) where a new panel was manufactured using recycled semi-conductor."

Jan 1, 2016

By K. G. Wheeland, K. G. Byberg

The occurrence of a secondary, dust-fuelled explosion following blasting of sulphide ores has been reported in mines in many countries, including canada, the USA, Australia and South Africa. However there has been little effort to document the events and develop effective control technology. Following a detailed investigation of an incident at the Geco Di vision of Noranda Minerals Inc. , the company held a conference of interested parties in October 1986 to review the state-of-the-art and to agree on action. '!his paper outlines the causes and effects of such explosions, the key conference points and conclusions, and subsequent information-exchange and teclmology-developrnent activities.

May 11, 1988

By Martha Gellner, Lutz Wuschke, Hans-Georg Jackel, Urs A. Peuker

"Electric vehicles are an alternative to the existing combustion engine driven cars. According to the EU Battery Directive a substantial recycling rate of at least 50 wt.-% has to be met for aged batteries since 2006. Existing recycling techniques are based on energy intensive pyro- and hydrometallurgical process, which are not able to recover all components. Aluminum and lithium for instance are slagged. The EU-Project “ABattReLife” investigated possibilities for a mechanical processing in order to create a sustainable process and a closed material loop from grave to cradle. After a sufficient liberation of the Li-ion batteries, components like the doped carbon black fraction (mainly lamination of electrode foils), the separator foil and the housing material can comparatively easily be separated from the other components by screening and air sifting. The remaining mixture consists of anode and cathode foils which have a similar free-settling ratio and are more difficult to separate from each other. A second comminution and compaction step modifies the particle size and shape as well as the degree of delamination. These changes influence the density of the electrode foils in order to improve the separation efficiency. Yield and purity of the generated metal concentrates were parameters to show if the separation was successful. The specific energy consumption for the different methods of processing was estimated in order to benchmark the cost-benefit ratio for each one.The studies have been accomplished with a zig zag sifter (model TUBAF), a hammer mill (model HM 340 Jehmlich) and with a Petkus-Sifter. Finally a process flow sheet was developed for a Li-ion battery recycling plant in pilot scale."

Jan 1, 2016

By Waldbillig. D.

A baseline of the poisoning effect of hydrogen sulfide (H2S) fuel impurities on solid oxide fuel cell (SOFC) anodes was developed using polarization testing. After the baseline behaviour was characterized, tests to study the effect of various H2S concentrations on the rate and amount of cell voltage degradation and recovery were performed. Attempts were made to improve the rate and amount of recovery by various methods. Testing was very reproducible, but significant electrochemical performance degradation was seen after all H2S poisoning tests even at an H2S concentration of 0.1 ppm. Degradation is initially quite rapid, but after a period of time the rate of degradation levels off. After poisoning was complete, the H2S flow was stopped and the cells were allowed to recover. Some recovery was seen after poisoning, but cell performance was never fully recovered.

Jan 1, 2005

By R. J. Brailey

"A USER'S VIEW OF CONVEYOR WEIGH SCALESThe Sudbury Operations of Falconbridge Nickel Mines Limited includes seven mines, three concentrators and a smelter. The flow of ore, concentrates, fuel and fluxes between and within these plants requires measurement for accounting and control. The design, installation and maintenance .of weighing systems falls within the responsibility of the Instrumentation Department of Falconbridge Nickel Mines thus al lowing a common approach to conveyor weighing problems and the benefit of a common spares supply. This paper gives a brief overview of the recent experience with conveyor scales within the Sudbury Operations and discusses the problem areas.GeneralThe best way to establish the total amount of material going to or from a process is with a bucket and a stop watch. Unfortunately the flowrates involved in mining plants make the buckets very large, but wherever it is feasible static weighing is the preferred method of determining total quantity. This applies particularly to batch systems, where the material can be brought to rest long enough to allow a very accurate weight determination. Any form of weighing in motion is susceptible to variations in the forces of the transporting system. A belt scale is affected by its position on the belt, idler alignment, support stiffness, variations in belt tension, material spills and build-up, and a host of other factors all of which require careful consideration in any installation.As with instrumentation applied to any system the plant should be designed to ensure that the best results can be obtained from the equipment. This means getting the scale supplier together with the conveyor supplier as early as possible in the designing of a new plant. Any corners cut in scale installation will be paid for later in poor results and/or increased maintenance."

Jan 1, 1975

By S. N. Kalyakin, D. S. Flett, M. A. Mulagaleeva, N. V. Gudkova, S. S. Serdyuk, V. I. Kuzmin, Institute of Chemistry and Chemical Technology SB RAS, O. A. Logutenko, V. N. Kuzmina, V. G. Lomayev

"The Chuktukon niobium-rare earth elements ore deposit is located in Siberia (Russia). Weathered carbonatite crusts are the basis of the ore deposit. The deposit itself is 3.5 km in length, about 800 to 1400 m in width and up to 200–300 m in thickness. The ores are composed of iron-manganese oxides (hydrogoethite, hematite, psilomelane, pyrolusite) and contain 3–7% of rare-earth phosphates (florencite, monazite) and 0.5–1% of niobium oxide (pyrochlore). The ore is completely finely dispersed and consists of oxide particles formed of compact, dense aggregates which makes ore dressing as well as leaching of the rare and radioactive elements very difficult. Several options for processing of these ores have been considered: 1) reduction of the iron oxides to magnetite followed by beneficiation with magnetic separation to produce a rare metal concentrate; 2) processing of the rare earth elements (REE) containing minerals by direct alkaline-acid treatment; 3) processing of the ores using nitric acid leaching in an autoclave.INTRODUCTIONThe Chuktukon niobium-rare earth metal ore deposit is located in Siberia, in the Krasnoyarsk region, 110 km from the Boguchan hydroelectric power station which has recently been commissioned. This mineral raw materials is capable of providing impetus for the modernization of the Russian rare metal industry because of its qualitative and quantitative characteristics. The deposit is located in a region of promising industrial development and is a part of the territoriy where the Russian Federation’s Program “Complex Development of the Lower Angara Region” is currenly being realized. The main program directions are creation and development of industrial activities in sectors such as power, metallurgy, oil and gas, gold, rare-metals, and timber. The program will aid the development of the niobium and rare-metal resources of the Lower Angara and neighbouring regions as well as increase the national production of REE and therefore import substitution (Lapin, 1997; Lomaev & Kuzmin, 2003; Lomaev & Serdyuk, 2011; Serdyuk, Lomaev, & Kontorovich, 2000)."

Jan 1, 2016

By N. Chow, W. McCombe, G. Remple, J. Nikkari, L. Nightingale-Mercer

Orano Canada Inc. (Orano) operates the McClean Lake mill in northern Saskatchewan, processing high concentration uranium ore, delivered in slurry form, from the Cameco operated Cigar Lake mine. This slurry is ultimately processed into the purified uranium oxide product known as calcined yellowcake. During the calcining process, sulphate (SO42-) entrained in the yellowcake undergoes thermal decomposition into sulphur dioxide (SO2). SO2 is a colourless gas that poses health and safety risks. Since 2016, an anhydrous ammonia dosing system was successfully added to the existing Venturi particulate scrubber system to provide efficient removal of SO2 from the calciner off-gas. Within the pH controlled scrubber solution, SO2 exists in a pH dependent equilibrium with sulphite/bisulphite (SO32-/ HSO3-). The presence of a significant fraction of reduced sulphite and bisulphite in mill solutions presents a hazard in downstream circuits. Should these solutions drop in pH, either through natural oxidation or inadvertent mixing with low pH solutions, the solution equilibrium will shift from SO32-/HSO3- in favour of SO2, resulting in the evolution of SO2 gas from any liquid surfaces. In 2018, Hatch Ltd. (Hatch) and Orano implemented a design change in the calciner scrubber system. Blowdown from this system is now treated in an oxidation pre-step utilizing hydrogen peroxide (H2O2) and anhydrous ammonia (NH3) for pH control, in order to convert the residual sulphite/bisulphite present in solution to stable ammonium sulphate product. This paper will detail some of the challenges and actions undertaken to minimize SO2 risk, culminating in the recent introduction of a novel system designed to oxidize sulphite/bisulphite and prevent mobilization from the calciner scrubber solution into other mill areas where there is the potential for acidification and SO2 release.

Jan 1, 2020

By Charles Tkaczuk

In order to remain competitive the mining industry must keep up with changes in technology. Many innovative technologies from the mining perspective are commonplace in other industries. A ?Global? review of technologies will often reveal existing technologies that can be innovatively applied in the mining industry. Industries, which are rife with proven solutions include, medicine, biotechnology, security, manufacturing, telecommunications, etc. This paper addresses the communications aspect of mining where greater productivity, lower costs and the ability to quickly react to mining related events is obtained through an increase in remote monitoring and operating control. A review of the communications systems in place globally reveals technologies that, with minimal modification, can be immediately applied to the mining environment. We discuss the concept, advantages and implementation of existing communications technology from an industry that is not usually associated with the mining industry. This technology will form the basis of a solid platform on which can be built a state-of-the-art process monitoring, control, and communication system. This lays the groundwork for providing one solution to the underground mining industry?s most difficult problem, establishing a reliable, maintainable and cost-effective underground bi-directional wired/wireless data, video and analog communications system. We need look no further than our own doorsteps to find such a solution. The cable that you see coming from the simple green or brown box on the boulevard into your home contains hundreds of television broadcast channels, FM radio channels and data channels. And if you have a set-top box, you are in control of it all. The Cable Television Broadcast Distribution System suppliers of today are at the leading edge of converging all the different methods of communications onto a common carrier, coaxial cable or fibre optic cable. There is no fundamental difference between providing a reliable communications network to a city/neighbourhood/home/personal computer than there is to a mining operation/underground level/equipment or person. The principle is the same. Only the application is different. Realizing this, we can capitalize on the efforts of other industrial sectors, to solve our communications problem. Where else can you find a solution to a problem that is mature, having been developed with the input of thousands of engineers, and having hundreds of millions of dollars spent on research and development, manufacturing, distribution, global presence and engineering support?

May 1, 2003

By The Staff

"A general description of the equipment, personnel and work sequence •being used in the sinking of a circular, concrete lined, 14 foot diameter shaft which at present is at a depth of 2,484 feet. Equipping, lining and sinking of the shaft is being carried out concurrently and waste is re-moved using a mechanical mucker.INTRODUCTIONTHE BUCHANS UNIT of the American Smelting and Refining Company operates a group of mines at Buchans, Newfoundland. Buchans is in the centre of the Province (Lat. 48°47'N.; Long. 56°50'W.), five miles north of Red Indian lake at an elevation of 900 feet and is accessible by 37 miles <Jf private railway which connects with the Canadian National railway at Millertown Junction, and by 47 miles of gravel highway, which connects with the Trans-'Canada Highway at Badger."

Jan 1, 1959

By Zhibao Li, Lanmu Zeng

The behavior of dicalcium silicate in NaOH-NaAl(OH)4-Na2CO3 solution is of significance for controlling the silica level in the production of alumina via the sintering process. Dicalcium silicate samples were obtained through a twostep approach: coprecipitation of calcium and silicate from CaCl2-Na2SiO3-NaOH solutions; and calcination of the hydrated precursor at 1200°C for 4 hours. The optimization of the synthesis parameters including temperature, solution concentrations and aging time was also investigated. Xray diffraction (XRD) and chemical analysis show that the calcined solids include dicalcium silicate with trace amounts of wollastonite. The solubility of the synthesized dicalcium silicate in HCl, NaOH, mixed NaOH-NaAl(OH)4 and NaOH-NaAl(OH)4-Na2CO3 solutions was determined. It was found that the solubility increases with increasing HCl and NaOH concentration. The effect of temperature on the solubility in HCl solutions is limited, but the solubility decreases with increasing temperature in NaOH solutions. The solubility of dicalcium silicate in NaOH-NaAl(OH)4 and NaOH-NaAl(OH)4-Na2CO3 solutions was shown to increase with increased temperature, Al(OH)3 and Na2CO3 concentration. The BromleyZemaitis model for the aqueous electrolyte system was selected to predict the solubility of dicalcium silicate. The model’s predictions yielded certain success compared with experimental solubility data.

Jan 1, 2014

By S. Kobayashi, N. Ohara, T. Aoki, S. Sakurai, M. Iwano, M. Shimo, I. Otsuka

"This project is the upgrading of a commuter line of approximately 76 km to improve the railway system in Istanbul metropolitan area. Railway tracks have been connected between Asia and Europe through a tunnel under the Bosphorus Strait. The length of these underground structures sums up 13.6 km. In this paper, the observational construction management based on field measurement performed at large scale underground railway station (Sirkeci station) constructed by means of New Austrian Tunneling Method (NATM) is described and the mechanism for generation of ground surface settlement above this station is discussed.Buildings above Sirkeci station are overcrowded. About 60% of the buildings are made of reinforced-concrete (RC) and others are of brick. Based on the investigation into the predicted settlement and inclination, necessary actions such as structural reinforcement and soil improvement have been conducted for dilapidated buildings.Rock mass around Sirkeci station consists of alternative strata of sandstone and mudstone. It is overall soft rock with an elastic modulus of 150 MPa, partly including fractured zones. Overburden is about 30 to 40 m. The thickness of unconsolidated sand layer distributed on the bedrock is about 10 m. As a result of in-situ permeability tests, the coefficient of permeability of the sand layer is about 1.0x10-3 cm/s. Fill layer of about 10 to 25 m in thickness covers the sand layer at the ground surface. The fill layer contains a lot of artificial waste like splinters of wood, brick chips and mortar chips, etc. in addition to gravel, sand, silt and shells. The coefficient of permeability of fill layer is estimated to be 1.0 x10-2 cm/s, which is one-order greater than that of the sand layer. Fill layer consists of ancient city ruins of ages respectively from the Eastern Roman Empire, the Byzantine Empire and the Ottoman Empire and has a lot of gaps.The underground part of the Sirkeci station was excavated through a ventilation shaft. Ground surface settlement occurred more than predicted. Therefore, back analyses were performed in order to precisely predict the next-step settlement. However, back analyses with elasto-plastic models could not simulate the actual phenomena and hence, an anisotropic-damage-parameter model developed by Sakurai (1999) was adopted for the back analysis. Furthermore, as the excavation of tunnel proceeded, the ground surface settlement exceeded the predicted value again. Based on the monitoring results, it seemed that pore water pressure decreased by the tunnel excavation resulted in the soft rock and soil to be contracted due to the increase in the effective confining pressure. A coupled hydraulic-mechanical analysis was applied to explain the relationship between decreased pore water pressure and ground surface settlement. The settlement due to drainage from tunnel wall was well-estimated in the coupled hydraulic-mechanical analysis.However, further settlement occurred more than predicted again and again. Though it was very difficult to clarify the reason of the large settlement, it was recognized that the unexpected ground surface settlement resulted from the existence of the large gaps in the fill layer that was greatly compressed. The final settlement reached up to 327 mm."

Jan 1, 2015