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By Kathy S. Kalenchuk

Damages have been observed in shafts, backfill infrastructure and the slick line at the Leeville Mine. Shaft damage (shearing and spalling of the concrete liner) is attributed to mine-induced rock mass deformations concentrated where regional faults intersect the shafts. Aggregate bin, mixer station and conveyor drive damage (shotcrete shearing, heave of concrete floor slabs and bending of a vertical steel beams) is attributed to rock mass squeezing induced by elevated magnitudes of the vertically orientated major principal stresses. Separation of the slick line has occurred do to extension of the stressshadowed rock mass immediately above the mined out areas. Three-dimensional numerical models have been developed and calibrated to simulated rock mass deformations with magnitudes similar to those believed to have produced the observed damages. By stepping through the mine sequence, models reproduce deformations at the same mining stage as when damage has occurred. Calibrated models have been used to forward project further damage over the remaining mine life.

Jun 1, 2012

By T. Imgrund, A. Bischoff, S. Spürk

"Specific conditions of underground coal mines at great depth, such as high temperatures, high rates of methane inflow and natural ventilation pressure provide considerable challenges for the reliable design of appropriate mine ventilation systems. For decades coal mining in Germany has coped with these extreme circumstances. Based on these experiences appropriate software tools for simulating mine ventilation networks have been developed and continuously enhanced. This paper examines differences in the simulation results and underlying calculation methods of two software solutions. The analysis is based on the comparison of FlowNetTM and VentSim DesignTM (Version 5.1) regarding the accurate prediction of fluid mechanical quantities and their validation with real measurements. A special focus lies on exceptional ventilation scenarios typical for deep coal mines, like gas inflows, fire events and buoyancy effects. The purpose of the comparison is the future utilization of the experiences gained during mining at up to 1,500 m depth for state of the art ventilation design. INTRODUCTION Ventilation is an essential component of mine operations—as providing fresh air to workplaces, diluting and removing explosive, toxic or asphyxiating pollutants and assuring sufficient climate conditions. On the other hand, the costs of ventilation contribute to a large extend to the overall operating costs of a mine, as the share in the energy consumption of a mine may be in the range of 25–50% (Belle, 2008). Accordingly, proper design of ventilation systems has been a task since early times. Consequently software for modelling of ventilation networks has been developed in order to improve efficiency and accuracy of calculations (Maleki, 2018). Compressible flow has not been considered by initial ventilation modelling software tools. In Germany, the consideration of changes in airflow density—depending on pressure and temperature—in the algorithms of ventilation simulation software has been started in 1974 by Duepre & Hofbauer. This development had been continued by the Pruefstelle fuer Grubenbewetterung (Test Centre for Mine Ventilation) and resulted in the release of a computer ventilation software named “Wetter”. The mine inspectorate of the German state of North Rhine-Westphalia, which supervises the major coal mining district in Germany, declared ventilation simulation based on compressible flow being “state of the art” in 1985 (Pollak, 1985). This pronouncement made allowance for assessing the consequences of underground fires and downtimes of main fans based on advanced software solutions."

Jan 1, 2019

By M. O. Pekguleryuz, D. S. Aydin

The high temperature oxidation and ignition resistance of Mg-(0-6) wt% Nd alloys have been investigated via isothermal and continuous heating experiments conducted in air atmosphere. Alloy composition is observed to be effective in low levels (~ 0.5 %) in the ignition temperature (Ti) of the alloys; the Ti of pure Mg increased from 630 °C to 770 °C with 0.5 wt% Nd addition. However, no noteworthy improvement was achieved with further additions up to 6 wt% Nd. The initial microstructure was observed to determine the oxide structure on the surface due to the differing oxidation behavior of the phases (a-Mg + Mg12Nd intermetallics). It has been found that the formation of a Nd-depleted region at the subsurface due to extensive Nd oxidation at the oxide/intermetallic interface lowers the protective ability of the oxide scale.

Jan 1, 2015

By G. M. Card, K. D. Card, B. V. Sanford

Abstract-The Canadian Shield and its extensions are traversed by an orthogonal system of northwest and northeast trending arch-style uplifts. These basement arches were formed by repeated vertical movements along pre-existing structures during compressional and extensional tectonism connected with events in surrounding Proterozoic and Phanerozoic orogens and ocean basins. The arches influenced patterns of sedimentation and tectonism in the intervening epicratonic basins and marginal platforms throughout the Proterozoic and Phanerozoic. Movements on the arch structures also triggered minor magmatism and controlled the location and timing of alkalic rock-carbonatite, kimberlite, and related intrusions in the Canadian Shield, the Western Canada Sedimentary Basin, and West Greenland.

Jan 1, 1997

By G. M. Card, K. D. Card, B. V. Sanford

The Canadian Shield and its extensions are traversed by an orthogonal system of north-west and northeast trending arch-style uplifts. These basement arches were formed by repeated vertical movements along pre-existing structures during compressional and extensional tectonism connected with events in surrounding Proterozoic and Phanerozoic orogens and ocean basins. The arches in?uenced patterns of sedimentation and tectonism in the intervening epicratonic basins andmarginal platforms throughout the Proterozoic and Phanerozoic. Movements on the arch structuresalso triggered minor magmatism and controlled the location and timing of alkalic rock-carbonatite, kimberlite, and related intrusions in the Canadian Shield, the Western Canada Sedimentary Basin, and West Greenland.

Jan 1, 1997

By Kamran Esmaieli

This paper investigates the behavior of ore pass walls under impact loads caused by material transiting through an ore pass. In particular it considers the influence of foliation in the rock mass surrounding an ore pass as both a triggering and accentuating cause of degradation. Based on empirical observations in several underground mines a numerical experiment was designed to understand the influence of rock mass foliation on impact-induced damage on ore pass walls. The distinct element method, and in particular the Particle Flow Code (PFC2D) was used to simulate three different rock masses surrounding an ore pass. Each simulated rock mass has similar properties but was defined by distinct dominant foliation (70o, 80o, 90o) along the foot wall. The numerical experiments investigated different scenarios whereby the walls were loaded by a projected rock fragment striking the foliated walls at a constant impact angle and velocity. The damage inflicted by the projectile rock fragment, on the foliated rock mass, was quantified using the number of impact-induced micro-cracks initiated on the ore pass wall. The results of the numerical analysis indicated that the presence of foliation resulted in greater damage zones in the surrounding rock mass. In addition, the extent of impact-induced damage to the ore pass wall increased as the angle of interception between the ore pass wall and the rock mass foliations decreases. This is in agreement with qualitative field observations.

Jun 1, 2012

By Masahiro Eguchi, Giuseppe Granata, Chiharu Tokoro, Hiroki Fukuda, Yuichiro Toba, Shungo Hobo

"Currently, large amounts of wastewater containing boron are discharged from industries like coal-fired power plants. Although coagulation-sedimentation is widely employed for their treatment, only a little consideration has been given to its mechanism. An additional problem is that the produced sludge has poor solid-liquid separation. This study is focusing on coagulation-sedimentation using magnesium, examining the mechanism and improving the solid-liquid separation. First, the co-precipitation with magnesium hydroxide was conducted against high-concentration boron wastewater with 500 mg/dm3as B. Second, in order to improve the solid-liquid separation by maintaining high reactivity, low-crystalline magnesium oxide was synthesized from magnesium carbonate by calcination at 400–700°C. It was tested as an adsorbent of boron and compared to co-precipitation with magnesium hydroxide. Co-precipitation showed high removal capacity. X-ray diffraction (XRD) of the sludge revealed the presence of other compounds besides magnesium hydroxide. This result suggests that other processes play a role other than simple adsorption on to magnesium hydroxide, and provides a plausible explanation for the observed high separability. As for the adsorption, the synthesized magnesium oxide immobilized as much or more amount of boron than co-precipitation. Furthermore, the results of fourier transform infrared spectroscopy (FT-IR) suggested the residual magnesium carbonate improved solid-liquid separability due to its poor solubility.INTRODUCTIONBoron is used in various industrial applications. In glass industry, the addition of a little amount of boron into glass products can enhance heat-resistance and chemical-resistance. Semi-conductor industry also employs boron as dopant for silicon. From these industries, large amounts of wastewater containing boron have been discharged. Additionally, coal-fired power plants have been recently discharging highly concentrated boron wastewater because the amount of boron contained in coal has been increasing due to a gradual decrease of the quality of coal. Since boron is partially proved to be toxic for animals, plants, and human beings (WHO, 1998),the guideline of the World Health Organization limit the boron concentration in drinking water to 2.4 mg/dm3(WHO, 2009).Because boron does not precipitate from solutions by simply changing the pH, the removal could be carried by operations such as adsorption or ion exchange. However, since ion exchange is an expensive operation with relatively low capacity, it is not suitable to treat the large amounts of wastewater produced by heavy industries like the coal-fired power plants. Therefore, coagulation-sedimentation method is still widely used as a suitable alternative way."

Jan 1, 2017

By J. W. Craig

THERE are, broadly speaking, three classes of refractories: acid, basic, and neutral. Fireclay, diaspore, silica, and the sillimanite group of minerals are included in the acid class, which for the most part are not very resistant to basic slags. The neutra! class includes chrome, graphite, and silicon carbide, while most important in the basic class are magnesite and dolomite. Although chrome is a neutral refractory, it has no sharp distinction from magnesitic refractoriness. The two are mineralogically (1) and chemically related, and there is available on the market a complete range of brick from straight chrome to straight magnesite. In many indus trial applications, one. type may be replaced by another. The present paper is confined entirely to such refractories. The following types of basic and neutra! brick, each sold under sorne special trade name, are available for use in Canada: (1) Burned chrome from crude ores (2) Burned chrome from treated ores (3) Chemically bonded (unburned) chrome-magnesite ( 4) Burned chrome-magnesite (5) Chemically bonded ( unburned) magnesite-chrome (6) Chemically bonded (unburned) high-iron magnesite (7) Burned high-iron magnesite (Regular) (8) Burned low-iron magnesite (9) Burned olivine-magnesite (10) Burned magnesitic dolomite-chrome (Magnecon) (11) Chemically bonded magnesitic dolomite-chrome (Magmecom) (12) Dolomitic brick

Jan 1, 1936

By J. -F. Blais, M. -O. Simonnot, J. Mocellin, G. Mercier, J. -L. Morel

Large quantities of ferromanganese sludge are generated as waste material by blast furnace during the manufacturing of ferromanganese. These slags are very rich in manganese, zinc and lead (5 to 40 %). These residues have been deposited in a pond in periphery of the steel industry. Considering the market value of the metals, these brownfield sites can now be considered as secondary resources. We have developed a hydrometallurgical process for selectively leaching Zn, Mn and Pb in order to produce compounds of Mn and Zn pure enough to be economically recoverable and a residue rich in Pb. Batch laboratory experiments were carried out to determine appropriate leaching conditions to maximize zinc extraction (100 %) and manganese extraction (90.0 %) with sulfuric acid and to generate a residue containing 15 to 30% of lead. This Pb residue is recyclable by another process.

Jan 1, 2015

By M. Massinaei

Recently constructed circuits have included multiple stages of columns in a variety of applications, from roughing to cleaning. The Miduk copper concentrator (in south-eastern Iran) is one of the unique mineral processing plants which use column flotation cells as rougher. As the bulk of final concentrate is produced by rougher columns, optimized metallurgical performance of these cells is crucial. This paper will present the study and optimization of, a froth washing system of columns. For this purpose, the cross-sectional area of orifices was increased and their orientation altered. Concentrate assay for copper and silica, in addition to bias rate were found to be the assessment criteria. Modification of the wash water system resulted in increasing the purity of rougher and final concentrate. Negative bias and short-circuiting of wash water into the concentrate launder were the main causes of improper froth zone washing in the former system.

Jan 1, 2007

By H. R. Huffman

"This paper reviews the history of iron powder production, and outlines the varions production methods. The uses of iron powder and the reasons for its use are also covered. The paper concludes with a look at future trends in powder metallurgy.INTRODUCTION TO POWDERSTHE IRON POWDER INDUSTRY is enjoying a very rapid growth. The annual consumption of iron powder is now at the 100,000-ton level, twenty times higher than it was at the end of World War II, and the yearly in-crease bas been almost consistent at 20 per cent. This is expected to increase, bringing the tonnage to 200,-000, or even (according to some experts) to 270,000, in 1970. In any event, powder metallurgy is expanding at high speed and making an important impact on the production of iron and steel products. Some indication of the faith in the future market may be indicated by the commencement of three new powder production plants in Canada with a total capacity of 136,000 tons annually."

Jan 1, 1969

By W. Petruk

"D. Doyle How large is the beam to which you referred? Are we considering Watts, Griffis the probe of a 1 micron sized particle?& McOuatReply Yes. The beam would be about 1 micron. We could enlarge or reduce it depending on the current in-put.D. Doyle Then chemically bound material we might not see. If you are restricted to 1 micron then you would not be able to separate things smaller than this. Is this not so?Reply We won't be able to analyse it but we will see it as the scanning electron microscope has a resolution down to about 0.1 microns. We should be able to get the general composition of such a grain plus its surrounding grains. We feel we can then make a reasonable estimate if it were as small as 0.1 microns. An accurate analysis would be achieved with grains of 3 and 4 microns.D. Doyle Would this have an application in the hydrocarbon field?Reply The lowest atomic number would be sodium. We wouldn't be able to go below that atomic number. Anything with sodiumor a larger atomic number would enable us to analyse the carbon.M. Fairwether Do you have any policy relating to priorities. For instance areCominco companies going to be limited in the amout of samples permitted to give everyone a chance because quite frankly our company, and I'm sure all base metals companies can hardly wait for the installation of this equipment. I can forsee two years back-log of work in the first month.Reply Quite frankly, I haven't looked at this. At the present time the work is under the START program but I suppose we will have to look at possible changes. Anything under the START program has first line priority.B. Thorndycraft Will the briquetting of samples be automated as well? Pinson MiningReply No, not at this point. Our polish section laboratory is first-class and can turn out 18 polish sections a day which is more thar we can handle.B. Thorndycraft With the capability of this machine to operate in a hands-off manner perhaps it could start to look for the 5 micron gold particle in tailings?Reply I have such a program using a wave-length spectrometer rather than the energy dispersive. The wave-length spectometer is about 10 times as sensitive and would scan the section much faster. A one inch diameter polished section would be scanned in about 7 hours for anything 1 micron or larger."

Jan 1, 1984

By A. Warczok, T. A. Utigard

"Slags from smelting of copper concentrates contains from 1 to 15% of copper. Copper is present in the form of copper or copper matte inclusions of size from 2 to 1000 micro, and as dissolved cuprous oxide. Removal of the copper requires the slag reduction, primarily reduction of magnetite and co-reduction of cuprous oxide. Thus, the kinetics of the slag reduction play an important role in copper recovery. Instantaneously, at the contact of carbon and a slag the gaseous film is formed. The magnetite and cuprous oxide reduction is going through a gaseous film, separating the slag and carbon of a coke or electrodes. The thickness of a gaseous film grows to a critical value and gas bubbles, containing CO and CO2, are created and rise up in the slag. Results of measurements of kinetic of the slag reduction with graphite showed high value of activation energy, close to the value of activation energy of Boudouard reaction. Strong temperature dependence of the reaction rate points out the thermal instability of the reacting system. It was found that the slowest process in the reduction stages determines the loop of CO and CO2 transfer and magnetite diffusion to the slag/gas film boundary. Strongly endothermic Boudouard reaction seems to cause thermal instability on the reaction surface. So, heat transfer to the reaction surface is very important. Due to low thermal conductivity of a slag the convection dominates in the heat transfer. So, any slag stirring accelerates the rate of reduction and coalescence of metallic copper or copper matte inclusions."

Jan 1, 2015

By J. W. Rogers, S. K. Schwartz

"The Cape Breton Development Corporation (CBDC) is a federal Crown corporation which operates two coal mines (Phalen and Prince Collieries), a coal preparation plant, a railway, a central workshop and a deep water shipping facility.The Sydney coal field consists of 11 major seams, which range from 0.8 m to over 3.7 m in thickness. Of the 2.4 billion tonnes of known coal resources in the field, approximately 550 million tonnes can be mined with present mining technology. These parameters define reserves which extend more than 8 km beneath the ocean to a depth of 1200 m. With today’s design and present high production faces, the colliery life is projected at approximately 20 years."

Jan 1, 1996

By A. L. Mular

"This paper summarizes the present-day usage of computers in the mining-metallurgical industry. The industry appears to be following a path taken by other industries in improving the operation of processing plants, production schedules, grade control and haulage performance. A reduction in the cost of computers and computing has been a significant factor.An attempt is made to forecast the future of computers in our industry. Such developments as time-sharing, mini-computers, and easy-to-understand process-oriented languages will lead to wider usage. Considerable strides have been made in the use of computers for laboratory data acquisition. In general, the implementation of new methods, new techniques and new equipment will require plant personnel to develop new skills. The universities are meeting this challenge by re-structuring curricula and offering special courses. Most vendors of computers already offer special courses within their own facilities at a customer's plant."

Jan 1, 1970

By Alessandro Navarra, Roberto Parra, Boyd Davis, Frank Mucciardi

A smelter scheduling algorithm has been developed, which allocates the oxygen production between the smelting furnace and the converter aisle, so as to maximize copper throughput. The algorithm is intended for daily operation planning, controlling the sequencing of the converter cycles, and the oxygen drawn by these cycles. In some cases, it may be worthwhile to decrease converter oxygen allocation in favour of the smelting furnaces. Thus, a better utilization of the oxygen plant can increase primary copper throughput by several percentage points. This principle is demonstrated through sample computations. The approach presented in this paper can be incorporated into smelter management software.

Jan 1, 2015

By Rene Cane, V. I. Lakshmanan, John Starkey, Richard May

"The Agrium Kapuskasing Phosphate Operation mines and processes up to 6,000 t/d of phosphate ore. Run-of-mine crushing to minus 6 inches is done in a toothed roll-crusher, while grinding is done in a SAG/ball mill circuit with no coarse recycle classification of the SAG mill discharge. The primary grinding mill is an 18 ft. diameter x 9 ft. EGL, 1500 HP variable speed SAG mill and the secondary mill is a 13 ft. diameter x 21 ft. long, 2000 HP fixed speed, ball mill. When hard ore was treated, the SAG mill restricted the tonnage that could be ground. When soft ore was treated, the ball mill and spiral classifier overloaded and restricted throughput.Recommendations from a plant benchmark and an ore hardness testing program, on how to better utilize installed energy in the Agrium SAG mill when treating soft ore, and how to obtain best results when treating hard ore, were checked in a pilot plant investigation in the 3 ft. diameter Starkey-PRO Pilot SAG Mill. Correlation between the ore hardness testing and the results from the 3’ Pilot SAG mill was very good. In addition, the work indicated the results that could be expected for the different ore types when using either smaller SAG discharge grates and/or a vibrating screen with 10 mesh square opening cloth.INTRODUCTIONAgrium Kapuskasing Phosphate Operation consists of a 6800 t/d open pit mine and a concentrator, near the Town of Kapuskasing in Northern Ontario. The two major ore types are sandy ore and cemented ore. Sandy ore is fine, soft and easy to grind in the SAG mill while cemented ore is harder, more blocky and difficult to grind in the SAG mill. The ratio of sandy to cemented ore in the deposit is thought to be in the order of 80:20 but can range as high as 5050, so it was important for the grinding circuit to have the ability to treat sandy ore alone."

Jan 1, 2002

By E. Rezazadeh Azar

Dump trucks are the main mean for hauling earth material within and outside of the construction and open-pit mining jobsites. The real-time monitoring of the material transportation trips is beneficial for proactive equipment management, volume estimation, and productivity measurement. The traditional manual observation is tedious, non-real-time, and expensive; therefore remote sensing technologies, namely GPS and RFID, have been employed for this reason. Ordinary construction videos are another costeffective alternative to monitor dirt loading and hauling operations in real-time. A vision-based system has been developed to recognize and count hauling trips. This system has three modules including object detection, tracking, and action recognition. This system processes videos taken from access roads in which it recognizes dump trucks and then tracks them throughout the viewfinder. The action recognition module is designed to reject false alarms and also terminate tracking. This way, the system is able to count the number of hauling trips and also record the time between each trip. Several state of the art computer vision algorithms were employed to develop this system. Some of these algorithms were modified using spatiotemporal information to minimize the inherent errors of the vision-based methods. The experimental results showed considerable performance of the system for practical application in the construction and mining sectors.

Aug 1, 2013

By L. J. Cunningham

Introduction The property of Rouyn Merger Gold Mines, Limited, is in Rouyn and Joannès townships, Western Quebec, seven miles east of the town of Rouyn. Traversing it is the east-west trending Cadillac-Bouzan fault. Diamond drilling in 1944 and 1945 along a shear zone south of the fault indicated an ore deposit lying at the contact between sedimentary and volcanic rocks and dipping approximately 60° to the northwest. In the summer of 1945 it was decided to sink a shaft to investigate the indicated ore zone. In the immediate vicinity of the deposit, bed-rock is overlain by clay beds, in some places as much as 70 feet thick. Consequently, possible shaft sites were limited to those locations where overburden would not be excessive. The most favourable site was about 125 feet to the south of the ore zone as projected vertically from bed-rock to the surface. Accordingly, it was decided to sink the shaft at this point, with an inclination of 60° N. W., paralleling the dip of the ore zone.

Jan 1, 1948

By K. S. Raja, B. Pesic, S. Kshetri

"We investigated the electrochemical corrosion behavior of commercial permanent magnetic material (NdFeB alloy) in 0.1 M NaH2PO4 solution (pH:4.75) containing 0 – 1000 ppm of chloride at room temperature (298 K). The material was evaluated in magnetized and demagnetized condition with different surface preparations such as: Ni-Cu-Ni coated, uncoated (bare), and anodized (in fluoride containing ethylene glycol at 60 V for 15 minutes to form a thick nanoporous oxide surface). The nickel coated magnetic sample showed reasonable pitting corrosion resistance up to 100 ppm chloride addition. The uncoated samples showed passivity in chloride free phosphate solution. Chloride additions caused pitting and the pitting protection potential was equal to the corrosion potential with 100 ppm chloride addition. Demagnetization did not alter the electrochemical polarization. However, the passive film formed on the magnetic sample showed higher charge carrier density than the film formed on the demagnetized sample. INTRODUCTIONSintered NdFeB permanent magnets exhibit excellent magnetic properties such as large energy product [(BH)max > 450 kJ/m3], high saturation magnetization (1.6 Tesla), and high coercivity (1.2 – 2.08 x 106 A/m) (Sugimoto, 2011). However, the NdFeB magnets are prone to corrosion attack because of the presence of Nd-rich intermetallic phases, such as Nd4Fe (Jurczyk & Jakubowicz, 2000). Nd-rich and B-rich intermetallic phases are distributed in a matrix of Nd2Fe14B tetragonal ferromagnetic compound in a permanent magnet. Generally, several types of Nd-rich phases are present in the magnet with Fe:Nd ratios ranging from 1:1.2 to 1:7. The volume fractions of Nd-rich and B-rich (Nd1+xFe4B4 type) phases are about 10% and 7% respectively (Li, Ma, Li, & Wang, 2011) . Among these intermetallic phases, Nd-rich phase has the most active electrochemical potential. Therefore, dissolution of this phase occurs in preference to other phases by galvanic corrosion when exposed to moisture. Since Nd-rich phases are present at the grain boundaries of the Nd2Fe14B matrix, corrosion leads to disintegration of the magnet."

Jan 1, 2012