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By Alex Henderson

The underground hard rock mining industry has had little change since the mobile equipment era began in the 1970s. Equipment has become larger and faster but has not kept pace with the following challenges: ? Improvements in safe production, ? Increasing demand for metals, ? Environmental improvements, ? Decreasing grades, ? Increasing depth of mining, ? More metal from underground vs. surface mining, and ? Energy and green house gas awareness. We are on the cusp of a new mining era and must rethink how underground hard rock mining must change in order to meet these challenges. This paper will show historical changes and propose a set of guiding principles for the next era of mining. Mining has changed over the last century. Initially mining was primarily an endeavor carried on by private companies with minor environmental controls and few social expectations other than employment. In the mid to later part of the century the mining industry was facing new challenges: deeper mines, the London Metals Exchange markets for pricing, and environmental concerns related to acidic rock drainage coming to the forefront. In today?s context, mining has evolved in complexity with the social and environmental aspects equally or surpassing the technical complexities such as expanding from mining hard rock to laterites, and mining lower grades or at greater depths. Nowadays, communities must be considered as partners, both locally and globally and the increased international visibility pushes the mining sector to take a more balanced approach to the business of mining (Fig. 1).

May 1, 2011

By Jose A. Caceres

Mine planning and mineral processing optimization are usually treated as two unconnected problems, especially at open pit and panel caving mines where the cut-off grade is practically the only variable optimized and analyzed for in the planning proposes. Using existing planning tool, the output is a reserve consumption strategy privileging higher grades. With the earlier consumption of the highest grades, every year produces revenues which are closer to the cost and potentially even below cost. However, there are other ore characteristics that can also affect the profitability of the operation. A new methodology has been developed, incorporating the grinding and flotation relationship into the mining economic models for the simultaneous analysis and optimization of the throughput-work index-recovery relationship through changes in the mining limits, sequence and redefinition of the reserve consumption strategy. A mine-site that implements this new planning strategy, can expect to increase the NPV from 5 to 15% depending on the actual operational settings. Two case studies have been developed, showing how the inclusion of the work index in the economic model changes the phase and mining sequence in an open pit mine and the caving sequence and the optimum column height in a panel caving mine.

May 1, 2004

By K. B. Young

Possibly the most complex fatigue problem associated with the development of the axial-flow 'gas turbine is discussed in its broader aspects from the metallurgical viewpoint. Reference is made to nodal patterns, interference diagrams, etc. The use of such data in analysis of a turbine :blade failure is illustrated. Special attention is given to the influence of some metallurgical variables affecting fatigue strength and, in particular, heat treatment is shown to have a pronounced effect on .the relative fatigue and creep strength properties of a nickel-chromium-cobalt base alloy suitable for turbine blade applications.

Jan 1, 1958

By A. B. Szwilski

"The various elements of longwall mine design are reviewed, particularly as they apply to condition s in the coalfields of the Plains region of Alberta. The following recommendations are made: (1) optimum panel lengths of 1000 to 2000 metres; (2) face lengths of 100 to 150 metres; (3) the use of retreat methods; (4) the restriction of floor undulations to less than 15 degrees. IntroductionThis article considers the elements of longwall mine design and is part of a short study that has been made of the feasibility of longwall mining in the Plains region, Alberta, Canada. The Plains region, with about 20 million tonnes, accounts for more than 80% of the coal resources of Alberta. The coalbearing strata in the Plains region cover an area of about 95,000 square miles. The geological formations dip very gently toward the southwest and, from a mining point of view, may be considered horizontal. The depth of the coal seams varies from several metres to over 650 metres. However, it is not anticipated that underground mining will be extended beyond the depth range of 25 to 250 metre s.The coal seams in the Plains region have been subject to many small mining operations in the past. The majority of these small mines were limited to a depth of about 50 metres, working mainly by room-and-pillar methods, although hand-filled longwall mining was often used.The development of new underground mining operations in the Plains region will have to be on a 'start-from-scratch' basis, especially regarding the installation of equipment. Longwall mining is more mechanized than any other method of mining and requires careful attention for the selection of new and expensive equipment. There have been many proven longwall advance and retreat systems in Europe and North America; mining conditions in the Plains region are more similar to those in the United States. Therefore, it will be essential for new mining pro jects in the Plains region to commence with proven system s and equipment; in time, perhaps an experimentation process could be attempted as experience is gained.Generally, the coal face is the key factor in mine productivity, which depends a great deal on equipment reliability, training and experience of the operators. The original design of coal faces must be flexible enough to cater for potential improvements so that running time can be increased."

Jan 1, 1980

By G. Itoh, S. Fukasawa

The Al-Zn-Mg alloys have been known to be susceptible to stress corrosion cracking (SCC), which is based on intergranular cracking arisen from hydrogen embrittlement (HE). The mechanism of HE has not been fully understood yet. In order to elucidate the mechanism of HE, we need to investigate the behavior of hydrogen in the alloys. In this paper, behavior of hydrogen in an Al-5.8%Zn-2.4Mg alloy was investigated by means of hydrogen microprint technique, a method to visualize location of hydrogen emission from specimen surface as silver particles. One side of the tensile test pieces was electrolytically polished and then covered with photographic emulsion. Hydrogen was pre-introduced into the test pieces from opposite side by cathodic electrolytic charging for 30min. Then, the test pieces were stretched with continuing the charging. After that, the specimen was fixed, rinsed, dried and observed with a scanning electron microscope. As a result, silver particles were observed on some grain boundaries.

Jan 1, 2015

By W. F. Moore

"In January 1981, Quintette Coal Limited (QCL) signed a 2a-year coking coal sales agreement with the Japanese Steel Industry which was followed by the commencement of mining operations in October 1982 and preparation plant operation in November 1983. During the mine 's startup, the town of Tumbler Ridge, the Anzac rail spur line, coal port facilities at Ridley Island plus numerous related elements of infrastructure were completed to support QCL and the neighbouring Bullmose operation in northeastern British Columbia. QCL's annual product coking coal levels have accelerated from 2.9 to 5.2 Mt between 1984 and 1986 with related increases in total mined volume from 14.8 to 41.0 M BCM between 1983 and 1986. This paper presents an overview of QCL 's current operation and related infrastructure. Development BackgroundDuring the 1970s, the Japanese Steel Industry (JSI) was forecasting a steady and significant growth in its steel production. By 1980 they were expecting crude steel production to increase from about 105 Mt in 1980 to 125 Mt by 1985 and almost 140 Mt by 1990.Discussions between Quintette Coal Limited (QCL) and the JSI for the development of the QCL project began in the 1970s and continued over a period of several years. During that time detailed and regular meetings took place, at which technical and commercial presentations were made to the JSI. The geology of the project area and the alternative mining methods and sequences were studied in detail. The new rail line which would connect the mine to tidewater was a critical factor and received particular attention. Alternate routes for the rail line from Tumbler Ridge to Prince George were the subject of much detailed study and discussions. The Anzac route was chosen in the best long-term interest of the northeast area development, after careful consideration and advice from the Japanese side.The new bulk coal terminal on Ridley Island at Prince Rupert was also a key factor and completed the development of an independent and new major coal field to supply the JSI. The QCL project and the development of the northeast area of British Columbia was a major strategical initiative of the JSI. It provided Japan with an important new coal field which was both self-sufficient and distinct from the traditional Japanese coal field resources in southern Canada, Australia, and the United States."

Jan 1, 1988

By M. Nakai, G. Itoh, R. Yamada, A. Kurumada

In order elucidate the mechanism for poorer fatigue properties of 7000 series aluminum alloys than those of 2000 series alloys, the effect of the test environment on the fatigue crack growth of the two series alloys was investigated, considering the relationship to hydrogen embrittlement. Two 7075-type and four 2024-type alloys were T6-tempered and T4-tempered respectively, and subjected to fatigue crack growth tests in moist and dry environments. When tested in moist air, fraction of intergranular crack path was higher in the 7075-type alloy with coarse equi-axed grains than in the 2024-type alloy with similar microstructure. This was in accord with the larger crack growth rate in the 7075-type alloy. Both the intergranular crack path fraction and the crack growth rate were decreased by changing the environment to the flow of nitrogen gas. Thus, the large fatigue crack growth rate of the 7075-type alloy is attributable to hydrogen embrittlement.

Jan 1, 2015

By O. A. Ojo, E. Anisimov, A. K. Khan

Electro-spark deposition (ESD) has recently generated a great deal of interest in processing aerospace materials. This is due to its potential for joining and repairing difficult-to-weld precipitation strengthened nickel-based superalloys without having problems of welding cracking that often plaque these materials. The short duration of current pulses involved in the process combined with the intermittent contact results in extremely rapid thermal cycle that produces nearly no heat affected zone in the substrate material. The microstructure of electro-spark deposited superalloy was meticulously studied in this work by scanning electron microscopy (SEM) and analytical transmission electron microscopy (TEM). The results show that in contrast to general assumption, the extreme rapid cooling rates involved in the ESD process did not produce partition-less solidification that is devoid of second phase microconstituents in the material. The secondary microconstituents were found formed along the intercellular regions of the solidification microstructure. The nature of these particles and the possible implication of their formation on mechanical properties of ESD processed material are reported and discussed.

Jan 1, 2015

By T. C. WEBB

In New Brunswick, significant potash deposits are intimately associated with rocks of the Lower Carboniferous Windsor Group. To date, two deposits high in sylvinite, up to 20 m thick, have been confirmed at depths between 490 and 1,035 m below surface near Plumweseep and Salt Springs. These areas are currently under development by the Potash Company of America and the Denison-Potacan Potash Company respectively. A third area, near Lower Millstream, is also known to contain potash-bearing evaporites and is now being explored by BP Exploration Canada Ltd. All three areas are situated in the western half of the Moncion Subbasin and are within 25 km of Sussex. Numerous similarities in stratigraphy, thickness, mineralogy and structure suggest that deposition of evaporites throughout much of southern New Brunswick was contemporaneous and extended over a considerable area. Future opportunities for potash exploration in the province thus seem excellent. A number of large unexplored areas remain in the Moncion and Cumberland Subbasins and in parts

Jan 1, 1984

By R. Abel

During the last eight years, the Ventanas electrolytic refinery has been improving its results by applying a series of new operational practices, such as the reduction of electrode spacing from 115 mm to 105 mm., raising the current density to 305 A/m2, modification in the operators shifts to about 70% of the workers, reducing the pulling cycles by two hours, and the erection of a new anode preparation machine. These improvements allowed an increase in the refinery capacity from 323,000 to 382,000 metric tons of electrolytic copper per year. In the same period it has obtained certification under the ISO 9001:2000 and ISO 14001:2004 standards. All of these developments have been achieved using conventional technology with copper starting sheets. The continuous improvement that is covered in this paper has allowed Ventanas to optimize its production, costs, and operational results. For the next years, it is planned to follow the same tendency, bringing the productivity of the plant to higher levels.

Jan 1, 2007

By E. J. Burrough

MR. J. J. McIntyre (International Coal & Coke Company, Ltd., and McGi1livray Creek Coal & Coke Company, Ltd., Coleman, Alta): Mr. Burrough's excellent paper, Metallurgical Coals of the Crowsnest Area, seems especially timely now, when the need for developing iron industries in the west, as well as in the east, is receiving so much attention. His -thorough review of the 'coking' industry is an especially valuable contribution, along with which the following brief remarks on coking in the Crowsnest Pass area of British Columbia and Alberta may be in order. When the Crowsnest Pass line of the Canadian Pacific railway was built there were great expectations for the non-ferrous metal industry; quite a number of smelter's were al-ready in operation in British Columbia and the northwestern United States, and further expansion was confidently expected. The suitability of the medium-volatile coking coals of the Pass for making metallurgical coke had been recognized from the time the fields were first explored. By the time the mines were fairly well developed there was already a market to war-rant the building of coking plants, and a common belief that expansion of the market would require a large coking industry. The first coke production was from plants built by the Crowsnest Pass Coal Company, Ltd., at Fernie, B.C. in 1903, and the International Coal and Coke Company, Ltd., at Coleman, Alberta. These plants were followed by others built by the Crowsnest Pass Coal Company, at Michel, B.C., by West Canadian Collieries, Ltd., at Lille, Alberta, and by Leitch Collieries, Ltd., at Passburg Alberta, and by a plant at Hosmer, B.C.

Jan 1, 1951

By Vic Briccardi

Energy Management Challenges The Holistic Standard to Energy Management Energy Management Information System (EMIS) "Best Practices?: Energy Management Maturity Curve De Beers Canada Profile & Mine Locations Significant ROI Driven by Real-Time Energy Visibility Mining Energy KPI?s Summary: What Does EMIS Deliver? Q&A Session

May 1, 2013

By Adriana Ramirez, Bradford C. Wesstrom, Blanca Olave

The Freeport McMoRan El Paso Copper Refinery optimizes electrolyte quality using a number of systems. The facility controls copper, arsenic, antimony and bismuth using electro-winning cells within the Tank House and Nickel Carbonate Plant Liberator Circuit (NCP). The NCP manages sulfuric acid content utilizing recycled electrolyte in the slimes autoclave as well as operation of the Acid Purification Unit, APU. The El Paso Refinery removes common sulfates using metal hydrolysis with sodium carbonate. Finally, a Mechanical Vapor Recompression, (MVR), at the water recovery plant removes sodium sulfate generated by the NCP. This paper will provide a summary of these operations. INTRODUCTION In the mid 1920’s Nichols Copper Company, in Laurel Hill, New York, recognized the need for a modern copper refining facility in the southwest. Because of the many railroad heads, affordable power and abundant labor supply, and the close proximity to regional copper smelters in Mexico, Arizona, and New Mexico, El Paso became the ideal location. In December 1928, ground was broken for the joint venture refinery between the Nichols Copper Company, Phelps Dodge, and the Calumet and Arizona Mining Company. In September 1930, Nichols Copper Company became a part of Phelps Dodge Corporation after a stock exchange. In July 1938, Nichols Division officially became Phelps Dodge Refining Corporation. In March 2007, Freeport McMoRan Copper & Gold acquired Phelps Dodge. Water is a precious commodity in the desert southwest, making conservation of this natural resource an important goal for the El Paso Operations. In the 1980’s, work on the treatment of slimes was improved through the use of pressure leaching of the refinery slimes using an autoclave. Due to the high tellurium content in the leached slimes solution, it was crucial to implement a method for its removal before the solution returns to the tank house electrolyte. A copper telluride cementation operation was installed for tellurium recovery and the ability for the recycle of the leachate and wash water to the refinery electrolyte. In October of 1997, ground was broken for the construction of the water recovery plant using an MVR to reuse process water, reducing water consumption by 25%. In 2002, electrolyte purification was further improved with the installation of an Acid Purification Unit, (APU) (Sheedy, Pajunen, & Wesstrom, 2007). The APU recycles 90% of the acids (both sulfuric and arsenic acids) back to the tank house electrolyte. The solution that passes through the APU is treated with soda ash to precipitate metals out of solution as carbonates and generates a sodium sulfate solution. This sodium sulfate solution is easily processed in the new water recovery plant, where the majority of the water recycles back into the plant as pure condensate. In 2012, the power plant at the refinery upgraded its Reverse Osmosis System to provide RO water to the tankhouse. This insured that the refinery would not have to bleed electrolyte for metals contained in well water such as: calcium, magnesium, iron and sodium chloride.

Jan 1, 2019

By G. W. Govier

The origin and limitations of the conventional and empirical equation for the interpretation of the results of back pressure tests on gas wells are discussed. Difficulties in data interpretation arise from many causes, including Jack of flow stabilization, uncertainties in connection with the friction calculation, and the effect of turbulence near the sand face in the reservoir. A procedure is developed to ac-count for the turbulence effect. This is based upon the theoretical equation for laminar steady state flow and current knowledge of turbulent steady state flow. The procedure involves the expression of the equation for combined laminar-turbulent steady state flow in terms of a turbulence contribution factor. This factor. is shown to be dependent mainly upon the flow rate per unit of pay thickness and the reservoir permeability. The method of interpretation permits the use of judgment based upon the theory and present day under-standing of laminar-turbulent flow and is considered an improved method

Jan 1, 1961

By S. Z. R. Pinkney

Positron Emission Tomography (PET) is a medical technique that produces three dimensional images of the body, commonly to aid diagnosis and treatment of tumours. PET has been developed by the University of Birmingham in order to track particles in an opaque system which is known as Positron Emission Particle Tracking (PEPT). The object to be tracked is irradiated. As the radionuclide decays positrons are produced; when these collide with electrons a pair of concurrent parallel back-to-back gamma waves are emitted and detected, from which the position of the object can be calculated. Stirred media mills are used for particle size reduction. The mill is usually operated at high solids loading with grinding media and has a polyurethane or polyurethane-lined steel pot and is thus opaque. For this study grinding media has been directly irradiated and tracked using the PET camera during the grind. The stirred media mill can be divided into cells of equal volume known as voxels. The fraction of the total time the irradiated media spend in each voxel can be shown in an occupancy diagram. The mean velocity and kinetic energy of the media for each voxel are calculated and also plotted. In occupancy and kinetic energy plots colour indicates the value of the voxel, in dimensionless time and Joules respectively. The arrow in velocity plots shows direction and length of arrow indicates magnitude of the mean velocity for the voxel. From these diagrams and further data analysis a detailed understanding of the flow patterns, media behaviour and high energy areas of the mill can be developed. Variables considered were the tip speed of the impeller and density of the grinding media. It was found that the grinder has three distinct regions: above, at and below the impeller with each region having its own flow patterns and velocity and kinetic energy profiles. These are different for each variable and so are used to characterise the grind. Tip speed and density of the grinding media were shown to both affect the velocity of the media and the proportion of time spent in the each region of the grinder.

Aug 1, 2013

By B. K. Choi, G. E. Kim, S. Noh, T. K. Kim

Oxide dispersion strengthened (ODS) steel has been developed as the most prospective core structural material for next-generation nuclear systems because of its excellent high strength and irradiation resistance. In ODS steel, finely dispersed nano-oxide particles with a high number density in the homogeneous grains can be very attractive to achieve superior mechanical properties at high temperatures, and these favorable microstructures can be significantly changed using process parameters during the mechanical alloying procedures. In this study, the effects of mechanical alloying times on the microstructure of 10Cr-1Mo ODS martensitic steel were investigated. Pre-alloyed powders with Y2O3 powder were mechanically alloyed for various milling times using a high energy horizontal ball-mill apparatus (model: symoloyer CM20). Powder properties such as the mean particle size, size distribution, and crystallite size were evaluated. Uniaxial hot pressing was employed to consolidate the milled powders. The results of a microstructural observation after the MA and UHP processes indicated that the homogeneity of the martensitic structures was considerably increased with the longer milling time. It is thus concluded that the mechanical properties of the ODS martensitic steel are greatly dependent on the mechanical alloying times.

Jan 1, 2015

By W. A. Green

Introduction While pilot-mill operations were being carried on at Flin Flon, as described by R. E. Phelan (1), a detailed topographic map was being made of the area in the vicinity of the ore-body for later use in laying out plans for the final plant. The area covered by this survey was 6,600 feet by 6,600 feet, with contours on 2-foot intervals. As mentioned by Mr. Phelan, it was definitely decided at the end of November, 1927, to take up the option on the Flin Flon property and to proceed immediately with the plans for construction of a metallurgical plant at Flin Flon to treat 3,000 tons of ore per day, and of a hydro-electric power plant at Island Falls, Saskatchewan, to supply power for the future operations at Flin Flon. Railway Built From The Pas to Flin Flon Just as soon as the decision was made to go ahead with the construction work and opening-up of the property, it was of course essential to give immediate attention to the building of a railway to the mine. Many years previously, a preliminary survey had been made for a railway to branch off the Hudson Bay railway at a point 4.7 miles northeast of The Pas, and, during certain negotiations in 1925, the Provincial Government of Manitoba had agreed to guarantee the railway bonds necessary to finance the building of the line, so that it was possible to organize for this work immediately. A contract was let by the newly organized Manitoba Northern Railway Company to the Dominion Construction Company, Ltd., and Tomlinson, for the building of the railway to the mine, a distance of approximately 87 miles (see Figure 1). The Manitoba Northern railway is a subsidiary to the Canadian National railway, and all engineering and supervision of the contractors was done by the Canadian National engineers. Actual construction work was started in January, 1928. The first 52 miles of the railway from The Pas to Cranberry Portage is over fairly level, although slightly rolling, country, and a considerable portion of the route is over muskeg area. Rails were laid on top of the frozen muskegs. Gravel deposits were opened-up along the line and, before warm weather; sufficient ballast .was distributed in the muskeg areas to prevent thawing under the track, and thus give the necessary support to allow uninterrupted transportation over the line.

Jan 1, 1935

By F. E. Patton

"IntroductionAT NORANDA, the strength of the ore and wall-rocks per-mitted mining in large open stopes. While some of the orebodies were small and could be mined out in one stope, in most cases their size was such that it was essential that ore pillars be left during the first stage of mining. In these cases, backfilling has been necessary for ground control and to facilitate the later recovery of the ore in these pillars.This paper discusses the development of the •backfill and •its use in pillar recovery.GeologyThe ore bodies at Noranda occur as replacement deposits in a block of rhyolite flows and breccias, bounded on the north by the Horne Creek fault and on the south by the Noranda Andesite fault. Mineralization consists of pyrite, pyrrhotite, magnetite, chalcopyrite, sphalerite, gold, and various tellurides.The main orebody is a massive sulphide deposit designated the 'H' orebody. It is elliptical in plan, measuring roughly 400 feet by 800 feet, and is divided into two zones -Upper H, extending from surface to the 1,500-foot level, and Lower H, from the 1 ,500-foot level to just below the 3,000-foot level.Mining MethodsOpen stope mining in both Upper H and Lower H zones has been fully described in previous publications (1). A brief review only of the mining methods will be given here."

Jan 1, 1952

By Bahri Öteyaka, Ali Uçar, Oktay Sahbaz

"A Jet Diffuser Flotation Column (JDFC) is a newcomer flotation device whose operation principles similar with Jameson cell but it has an essential change in downcomer. By taking into account the hydrodynamic and fluid mechanic principles (Sahbaz et al. 2013) downcomer was changed as a diffuser, therefore turbulence at the end of the downcomer was reduced to provide better aggregate stability and homogenous dissipation of the bubbles in the separation tank. Thus the performance increase has been aimed for the coarse particles.According to theoretical results, obtained by the formula of Oteyaka (1993) showing the relationship between velocity gradient and maximum floatable size for the various contact angles, the d50 of quartz flotation of JFDC is about 240 µm and 310 µm for the contact angle of 50° and 60°, respectively. This result was verified by the experiments. According to the experimental results; d50 which was accepted the maximum floatable particle size of quartz flotation of JFDC was about 256 µm and 300 µm for the contact angle of 50° and 60°, respectively.INTRODUCTIONFlotation is a kinetic process used for separation of hydrophobic particles from hydrophilic particles. There are many different parameters affects the success of the flotation and particle size is one of them. While the flotation is very efficient for intermediate size, the efficiency of the process starts to decrease for both fine and coarse sizes (Trahar, 1981; Muganda et al., 2011). Therefore; researchers have tried to find a solution for the efficiency decrease in fine and coarse sizes by modifying the chemical condition and designing the new devices. For example, Jameson cell is a unique device for the fine particle flotation due to the suitable design and fine bubble producing (Jameson, 1988; Evans et al., 1995; Sahbaz, 2010). Because of this success operation the Jameson cell is applied more than 200 flotation plants in worldwide. On the contrary, the efficiency of the cell decreases for coarse particle flotation due to the turbulence occurred in the separation tank (Sahbaz, 2010; Cowburn et al., 2007). That’s why, new flotation device was designed in loboratory scale by Sahbaz, Oteyaka and Ucar in 2010s and it has been called as Jet Diffuser Flotation Column (JDFC) recently."

Jan 1, 2016

By Les Philips

National Institute for Safety and Health?s (NIOSH, USA) Office of Mine Safety and Mine Safety and Health (OMSHR) has definitions for: -Proximity Detection as detection of personnel, vehicles and other objects near a machine using some type of sensor technology -Proximity Warning (aka Collision Warning) as detection of personnel, vehicles and other objects near a machine resulting in alarms that ?Warn the operator only ?Warn the operator and nearby personnel (two-way) -Collision Avoidance as the processing of sensor information resulting in control signals or actions that alter machine status/movement to avoid a collision by ?Computer control ?Human control

May 1, 2013