Search Documents

By William J. Purdy

Successful design, operation and completion of a surface waste management facility for a diamond mine located in Canada?s northern environment requires careful planning to minimize short and long term environmental impacts. As part of the mine development application process, best practice standards were applied using conventional engineering to reduce the environmental effects of the mine waste facility at the Snap Lake Diamond Project. This paper presents the design criteria, site conditions, material characteristics and engineering management objectives considered for optimization of the development plan. Insight into the engineering analyses, development alternatives, monitoring program and reclamation strategy plan to be undertaken during mine operations to provide opportunity for adaptive management and to minimize environmental impacts is provided.

May 1, 2004

By H. J. McQueen

Before 1950, hot working was simply deforming above the recrystallization point and gave a soft product compared to cold working. From 1960 onwards, improved testing in compression and torsion (stress, strain rate, temperature, quenching) provided valid specimens for microstructural analysis by polarized optical and transmission electron microscopy (TEM). Indeed, TEM was essential to uncovering the hot working mechanisms because it could distinguish between cold and hot substructures (dynamic recovery) in either initial or new grains (dynamic recrystallization). Over the years, teams at Concordia, McGill and UBC obtained NSERC support for students and equipment. CANMET built up a hot forming group having capabilities from high-rate cam-plastometer compression to rolling of experimental alloy billets; this was combined with latest metallographic instruments for fundamental research. Al alloys of every class (2000, 3000, 5000, 7000, 8000) were studied to understand the effects of solutes, precipitates, dispersoids and composites. The complex flow patterns in extrusion were clarified and modeled by finite element methods. Physical simulations of rolling schedules (up to 20 passes and reductions of 98%) by torsion provided evidence of microstructure development during both the passes and the softening intervals, thus clarifying development of texture in different alloys. The results frequently appeared in proceedings of Light Metals symposia and Canadian Metallurgical Quarterly

Jan 1, 2011

By Paul Hosford, Tim Haldane

"The paper describes the fast-track development of the project from feasibility study through to detailed design and construction, highlighting the process adaptations for handling sticky ore and water management in a tropical environment, and subsequent commissioning and operating experience of the mine. The paper discusses the geological setting, the environmental and socioeconomic considerations in developing and operating a mining operation in an underdeveloped country and the logistical challenges involved in bringing a large capital investment into Central America.INTRODUCTIONGlamis Gold Ltd. acquired the San Martin project in Honduras as a result of its merger with Mar-West Resources in late 1998. Despite the prevailing low gold price environment at the time of acquisition, Glamis anticipated rapid development of the San Martin project due to the quality of the deposit and other positive factors.Following favorable exploration and permitting activities in the first half of 1999, Glamis prepared a Feasibility study. In October 1999, Glamis decided to proceed with the development of the project and selected Hatch to provide the engineering, procurement and construction management services for the project. The San Martin project was in full-scale commercial operation approximately 14 months after the receipt of Board approval, and by July 2001 the San Martin project was operating at approximately 150% of its feasibility design capacity."

Jan 1, 2002

By Stefan Wallner, Andreas Filzwieser, Stefan Konetschnik, Reinhard Preiss, Iris Filzwieser

"Process Safety Management for METTOP means avoiding risks as far as possible - but also dealing with the residual risk by using all existing management tools or external assistance, if required. The presented paper has two parts. The first one introduces a new and very safe cooling technology for metallurgical furnaces. The second part shows how to deal with the residual risk as well as minimize it by using the tapping area of an electric arc furnace as an example.Today more and more intense furnace operations require effective cooling in order to achieve low refractory wear and good furnace lifetime, making cooling technology an important aspect of furnace operation. However, the use of water - today’s standard cooling medium - has some disadvantages, as it can cause problems both during furnace start up and operation, namely hydration problems, corrosion, and explosion.To overcome the disadvantages of water, a new cooling technology using an alternative cooling medium, namely ISIS B (a special kind of ionic liquid) was developed. The main advantage of ISIS B is the fact that no explosion occurs when this liquid comes in contact with molten metal. The working temperature range of ISIS B of 50 to 200 °C results in other advantages as there are no corrosion problems and no risks of hydration.The fact that no explosion occurs when ISIS B contacts molten metal leads to a revolutionary solution for the metallurgical industry in terms of safety. Especially in critical areas - like tap-holes - new safety standards can be achieved.Together with the TÜV Austrian Holding AG a risk analysis was done for a water cooled tap-hole as well as for a tap-hole cooled with ionic liquids. It is shown that using the new technology the risk can be decreased dramatically and the importance of a best available technology is described."

Jan 1, 2014

By Robert Harris, Peter Pheeney

"The Murray Brook gold mine operated from September 1989 to March 1991. Approximately 1.2 million tonnes of gossan were mined from an open pit and treated at a rate of 900 tonnes per day. The facility applied an agglomeration vat-leaching cyanidation plant for gold and silver recovery. The leached ore or tailings were rinsed of residual gold and cyanide and placed on an adjacent clay lined pad for storage and containment. A 50,000 tonne heap-leach demonstration project was constructed at Murray Brook in 1992 to recover copper and zinc from ore located in a sulfide-rich zone occurring beneath the gossan. The operation proved unsuccessful because of poor recoveries and low metal prices. The project terminated in the same year.A corporate decision was made in September 1999 to undertake complete and final reclamation of the Murray Brook site. Jacques Whitford and Associates Limited were contracted to develop the final reclamation plan and to assist the company in presenting the plan to the New Brunswick government for approval. The government approved the plan in January 2000. Two important reclamation issues were the mobility of mercury from the gossan tailings and the potential of acid mine drainage from exposed sulfides. The mine site is situated upstream of a productive river system, and the issue or impact of chemistry changes to the environment over the long term became an overriding factor in the development of the reclamation plan.A resource assessment of the gossan tailings in 1999 indicated an average concentration of mercury of 40 ppm. The mercury occurred naturally as the mineral cinnabar, but the exposure to residual cyanide (less than 10 ppm) over several years in the pile has likely caused much of the cinnabar to decompose into more soluble mercury forms. The reclamation plan specified the replacement of all sulfides to the pit followed by approximately 600,000 tonnes of gossan. To ensure “fixing” of the mercury, the gossan was replaced in compacted lifts and both the remaining pile and that replaced to the pit covered with available till and compacted. The reclamation work was successfully completed in September 2000 and the chemistry of the receiving environment will be monitored over a three-year period, after which the company expects to achieve walk away conditions."

Jan 1, 2001

By Charles Knilans, Tassos Grammatikopoulos, Nicole Hoffmann

"Twin Metals Minnesota LLC, (TMM) has recently completed a prefeasibility study evaluating the development and operation of an underground copper (Cu), nickel (Ni), platinum (Pt), palladium (Pd), and gold (Au) mining project on the Maturi deposit in northeastern Minnesota.The Maturi deposit is a magmatic Cu-Ni-sulphide deposit occurring along the basal contact of the South Kawishiwi intrusion, comprised of heterogeneous troctolites to gabbros forming a tabular body designated the BMZ (basal mineralized zone). These rocks provide the major gangue mineralogy (plagioclase, olivine, and clinopyroxene) with local, minor rock-forming orthopyroxene, biotite, magnetite, and ilmenite. Altered silicates exist within local fracture and/or alteration zones, which are commonly associated with minor faults in the regional area. The Maturi deposit is comprised of four main mineralized zones within the BMZ, referred to as Stage 1, Stage 2 (S2), Stage 3 (S3), and Upper Heterogeneous. Chalcopyrite, cubanite, pentlandite, and pyrrhotite are mainly hosted within the S2 and S3 units, with talnakhite frequently occurring within the S3 unit.A cross-discipline approach combining geology, geochemistry, metallurgy, QEMSCAN™ mineralogy, and mine planning has been implemented to develop a preliminary geometallurgical model and life of mine metallurgical performance forecast. This paper provides an overview of the methods that were used to develop the model and forecast, and discusses the advantages of such a model in project development and evaluation.INTRODUCTIONThe TMM Project proposes mining a copper-nickel-palladium-platinum-gold-silver (Cu-Ni-PGM) magmatic sulphide deposit situated in the Duluth Complex of northeastern Minnesota, USA. The prefeasibility study proposes a 45,000 million tonnes per day mine and concentrator facility to produce two saleable concentrates. The mine will access two separate deposits, Maturi and Maturi Southwest. Saleable concentrates are the final products of the sequential flotation plant where a high grade Cu concentrate is produced followed by a Ni concentrate."

Jan 1, 2015

By David Whalen

Mobile equipment in oil sand mining operations experience more maintenance problems than similar equipment in other surface mines, due to soft underfoot conditions. Oil sand properties are known to vary with temperature, bitumen content and previous loading cycles. One of the challenges is the widely variable underfoot pressure which supports shovels and trucks. In the case of a heavy hauler driving on in-pit roads, each tire is supported by a different ground stiffness resulting in an apparent uneven surface. Driving over uneven ground causes twist in the truck frame, which is transmitted to the dump body. Through a finite element analysis of a haul truck dump body, it was shown that slight frame twists produce localized stresses in the intersections of the floor stiffeners. These stresses are at times greater than those resulting from the maximum ore weight and are primarily responsible for cracking in these intersections. Syncrude maintains high quality haul roads, which are constructed of gravel, and makes every effort to keep the shovel pit roads as smooth as possible. This problem cannot be avoided through operational practices only and must also be accounted for in the design of haul truck bodies.

May 1, 2003

By Ilpo O. Auranen

Background: Mines of today are moving ever increasing tonnages of rock. The new ore bodies tend be of lower grade and located deeper in the earth?s crust. The industry?s focus to overcome this ?deeper but poorer? ore problem has traditionally been to lower the costs by increasing the scale of mining. This has resulted in an ever increasing size of mining equipment like drills, loading shovels, dump trucks. The main focus has been in reducing the cost per ton of mining. This cost focus has often resulted in increased waste rock dilution and more ore losses. From costs to value: Waste rock dilution means waste rock in the concentrator feed. It?s value in open pit mining is equal to the value of ore it replaces. In underground mining, waste rock dilution?s value is equal to the value of ore it replaces added to the costs of mining it. It is commonly accepted that waste rock dilution in open pit mining ranges between 5 and 20% and in underground mining between 5 and 40 % . In a typical large open pit mine ore value is from 20 to 60 USD per ton and mining costs are 1 to 3 USD per ton. One percentage point reduction in waste rock dilution represents savings corresponding to about 20% of total mining operation costs. The difficulty of reducing waste rock dilution comes from the complicated nature of the ores. Accurate ore waste-border detection has not been possible due to excessive costs. Core drilling combined with geochemical lab analysis is the most accurate method for locating ore waste borders. However, it is also expensive and time consuming, which is why it is often combined with somewhat lower cost methods like sampling drill cuttings from blasting drill holes or from reverse circulation drills and analyzing them in a laboratory. The main drawback with these methods, in addition high costs, lies in the sampling accuracy and in the quality control of the whole process when a large number of samples have to be handled manually. In every mine it is possible to halve waste rock dilution by using new on-line analysis technology .

Oct 1, 2009

By A. Dave Mackintosh

In 2001, at the CIM AGM in Quebec, a paper discussing poor ground conditions in a newly opened area at Agrium?s Vanscoy Potash Operation?s, suggested load transfer around old workings as a possible reason for the early room failure. High closure rates are expected in deeper regions however the rapid failure of walls immediately behind the face resulted in protective guards being mounted on and behind the borer. The high closure and early rib failure continued well past any reasonable distance to be explained by load transfer around old workings and investigations continued into possible reasons other than simply depth. Detailed investigations into the mineralogy and crystal fabric of the ore zone provided one possibility, which combined with a changed borer cutting profile are now believed to have contributed greatly to the poor conditions.

Apr 1, 2005

By M. W. Lewis, J. Werner

Fluctuating metal prices, declining head grade, and increased operational costs are forcing many open pit mining companies to look to their balance sheets for significant cost reductions in order to remain competitive. Maintenance continues to represent a significant proportion of the total operating costs in the mining industry. Compared with the other major cost components of the mining process, very little effort has gone into maintenance optimization. The potential payoff from maintenance optimization on the cash cost of the commodity is enormous. A large percentage of these costs are incurred in unscheduled maintenance events, which typically cause serious disruptions to the production process. These maintenance-induced production losses can be a significant contributor to the overall operating costs. A structured proactive maintenance approach using the latest advances in technology can achieve dramatic cost reductions and productivity improvements. Remote condition monitoring systems are becoming increasingly commonplace and have the potential to identify problems prior to failure. Detection of equipment degradation prior to failure will enable repairs to be scheduled thereby reducing costs and interruptions to production. Remote condition monitoring technology has evolved rapidly in recent years, with a host of new tools becoming available to assist mine operators in improving their maintenance operations. These tools have capabilities such as remote real-time vital signs and performance monitoring, alarm/event handling, trend analysis, and maintenance workflow management. When these monitoring tools are used in conjunction with a mine management system, the vital signs data can be integrated and associated with maintenance history, predictive maintenance data, operational information, and geographical information. This integrated approach to the management of vital maintenance data will help shift the mobile equipment maintenance paradigm from reactive to proactive. This paper will introduce a proactive approach to the management of the maintenance process and the tools required to facilitate this process.

Jan 1, 2005

By Michel Robert

"In 1974, Copperfields Mining Corporation and Soquem formed a new company, Niobec Inc, to bring the niobium deposit of the St-Honore carbonatite into production.St-Honore is located in the Saguenay area, near the cities of Chicoutimi and Arvida, and about one hundred and forty (140) miles north of Quebec. The discovery of the carbonatite complex was made in the fall of 1967 as a result of an airborne radiometric survey in search of uranium. The detailed exploration of the carbonatite indicated two niobium-bearing formations besides the original discovery of a rare earths zone. During the following years, the niobium formations were defined by diamond drilling and a decline was driven down to obtain adequate samples for metallurgical evaluation. In 1974, after seven hundred (700) bench scale tests, eleven (11) months of pilot plant 2nd a worldwide market research, a joint decision was made to initiate the development of a fifteen hundred (1500) T.P.D. mine and mill, under the management of Teck Corporation. The construction of the facilities were completed in early 1976 both on time and within budget. Niobec is now the only north american and the world second largest producer of Niobium concentrate.The process used at Niobec was developed from the pilot plant programs and later modified by the mill personnel. A simplified flowsheet for this process is shown on the slide. Briefly, run of mine ore is crushed to minus 5/8"" and fed to a rod mill, ball mill, and screens circuit where the ore is ground to 92% passing 65 mesh. The ore is deslimed in two stages of cycloning, and the final cyclone overflow at 85% minus 11 microns goes to waste. The cyclone underflow is conditioned prior to flotation of a carbonate-apatite concentrate. This concentrate is cleaned twice and then pumped to tails. The carbonate rougher and cleaner tails are cycloned in two stages to change the process; water and then sent to the pyrochlore rougher flotation. The rougher concentrate is cleaned five times. This is followed by pyrite flotation to remove sulfur, leaching with hydrochloric acid to remove phosphorus and dyed to less than 0.1% moisture before being sent to packaging."

Jan 1, 1978

By M. -C. Noël, G. P. Demopoulos

In this work the formation and environmental stabilization potential of arsenate-containing fluoroapatites is considered. In particular in this research various compounds were precipitated from synthetic solutions containing fluoride, arsenate/phosphate and calcium by varying different parameters-temperature, Ca:As ratio, pH, and P:As ratio, and aging time. The results obtained helped determine the operating window that should be used for the formation of highly crystalline fluoroapatites, in particular svabite (Ca5(AsO4)3F). It was found that svabite has a specific pH range of precipitation, with lower pH yielding CaF2 and calcium arsenate compounds such as CaHAsO4•H2O. At higher pH, a mixture of svabite and johnbaumite (Ca5(AsO4)3OH) precipitated, yielding a less stable material. This range of precipitation varied with the concentration of arsenic in the starting solution, and widened with higher initial concentrations of Ca2+, AsO4 3- and F-. Furthermore, svabite/fluoroapatite solid solutions were formed by using the same procedure as svabite but replacing some of the arsenate in solution by phosphate. The increase in phosphate content yielded a gradual change in morphology and crystallinity. Work on stability evaluation is currently under way.

Jan 1, 2014

By M. K. Mishra, U. M. R. Karanam

Relative to slender pillars, larger size pillars exhibit improved strata control. Fly ash, though traditionally treated as a waste product, is emerging as an alternate engineering material. This paper deals with the development of a strong fly ash composite material with additives. The geotechnical properties of this fly ash composite were determined and used to trap model core pillars, which resemble squat pillars. The trapped samples were tested under uni-axial loading in the laboratory and the results showed higher load-bearing capacity of the model core pillars. The reinforced fly ash composites provide lateral confinement and exhibit improved post- failure behaviour of the model cores.

Jan 1, 2008

By T. Banerjee, D. Felsher, G. Leavoy

"Lake Shore Gold is engaged in commercial gold production at both the Timmins West and Bell Creek mines, located in Timmins, Ontario. Run of mine ore is processed at the Bell Creek mill which consists of a conventional gold mill flow sheet involving crushing, grinding, gravity concentration and carbon-in-leach (CIL) for gold recovery. Since 2009, the operating capacity of the mill has been upgraded from 2000 tpd tonnes per day (tpd) to over 3,000 tpd. The most recent expansion involved the installation of a low aspect ratio SAG mill to replace the secondary crusher. Without operational data on the low aspect mill, combined with a site team that was new to SAG milling, there were many challenges in achieving the target throughput from the circuit. Through the implementation of AwaRE advanced controllers, running in closed loop with PRC fragmentation cameras as well as embedded PARC modules within the Allen Bradley PLC, the site was able to rapidly develop a best operating practise and has been successful in creating a stable and consistent operational environment. The process, lessons learned and eventual solution will be reviewed in this paper.INTRODUCTIONLake Shore Gold is engaged in commercial gold production at both the Timmins West and Bell Creek mines, located in Timmins, Ontario. Run of mine ore is processed at the Bell Creek mill which consists of a conventional gold mill flow sheet involving crushing, grinding, gravity concentration and carbon-in-leach (CIL) for gold recovery. Since 2009, the operating capacity of the mill has been upgraded from 2,000 tpd tonnes per day (tpd) to 3,150 tpd. The most recent expansion involved the installation of a low aspect ratio SAG mill to replace the secondary crusher. This endeavor was split into two phases: the expansion of the back-end (Phase 1) and the front-end (Phase 2) of the mill. Phase 1 of the expansion was completed at the end of 2012 and involved enhancements and capacity addition to the leaching and adsorption circuits, which increased the mill’s capacity to 2,500 tpd. Phase 2 of the expansion commenced at the end of July 2013 and involved the expansion of the crushing and grinding circuits. The expanded front-end of the mill now has a capacity of 5,500 tpd, and processes ore from both Bell Creek and Timmins West mines. The updated flow-sheet, as shown in Figure 1, illustrates the replacement of the two-stage crushing and ball milling circuit with a single stage crusher and a low aspect ratio SAG mill."

Jan 1, 2015

By Hua-Zhong Yu

Gold is one of the most widely used substrate materials for self-assembly. Self-assembled monolayers (SAMs) prepared from alkanethiols and their derivatives on gold are the most reliable and well-studied systems to date, which have attracted much attention because of interest in two-dimensional molecular assemblies, and of their potential applications in molecular devices, sensors, and functionalized interfaces. Gold electrodes are also very important in microelectronics and electroanalytical chemistry. This work reports the characterization of a new type of gold substrates for self-assembly. The gold substrates are constructed from recordable compact disks (R-CDs) with simple and straightforward wet-chemical treatment, and can be made at desired sizes and shapes that satisfy different experimental needs. In particular, an easy, inexpensive, and reproducible method to prepare self-assembled monolayers (SAMs) on CD-R gold substrates after removing the protective polymer films with concentrated nitric acid was described.

Oct 1, 2003

By Zhuofei Yang, Jidong Kang, David S. Wilkinson

The fatigue behavior of AM60 high pressure die casting magnesium alloys was studied in a straincontrolled manner. The fatigue test was interrupted every 2,000 cycles for X-ray tomography scanning. The specimen was removed to be scanned on a desktop micro-CT system. The value of using X-ray tomography in a fatigue properties study was assessed with respect to porosity, cracks and fracture surfaces. The 3D analysis and model results showed porosity could be well measured and modelled in 3D. Defects bands are made of pores under 50 µm in volume-equivalent sphere diameter. Larger pores are randomly distributed in the region between two defect bands. Observation of cracks by X-ray tomography occurs in three ways such that the 3D model gives the best illustration of crack-porosity interaction while the other two methods have better detectability on crack initiation and crack tip observation. X-ray tomography is also of value in failure analysis on fracture surfaces. By summarizing X-ray tomography data during fatigue testing and observing fracture surfaces on a 3D model, a better understanding on the crack initiation, crack-porosity interaction and the morphology of fracture surface is achieved.

Jan 1, 2014

By J. F. Archibald

This paper reviews the formation of the Canadian Mining Education Council (CMEC) and its terms of reference. CMEC considers that Canada?s mining schools represent a distinct competitive advantage to the Canadian Mining Industry. The core objective of CMEC is to reinforce the links between the constituent schools and their individual Industry Advisory Committees. The latter traditionally provide the schools with a great deal of guidance on a range of planning issues, including recruitment, curriculum, research and infrastructure. Beyond those bounds CMEC intends to improve its ability to network with the industry and government. It is concerned overall with the objective to raise the quality and level of its educational and research contributions to meet the needs of industry and society.

May 1, 2002

By K. C. Viveros, R. R. Ambriz, C. García, F. De Villèle, A. Talha, D. Jaramillo

Cold hole expansion on base metal, weld metal and heat affected zone of 6061-T6 aluminum alloy welds was simulated by means of finite element method. Three dimensional compact test models with a previous fatigue crack length with a relation of ??= a/W = 0.3, were used to analyze the hole expansion process. Considering the local mechanical properties for each zone of the welded joint, the optimal expansion degree (1.64 to 2.46 %) was determined. The residual stress field, through thickness, after the expansion process in all welding zones, were correlated with the crack opening displacement obtained by finite element analysis. It was observed, that compressive residual stress fields for a post-expansion, in different crack lengths, provided a crack closure mechanism for base metal, weld metal and heat affected zone. Contrary, the crack remained open when residual stresses are positive. The results are given as tangential stresses versus distance from the edge of the cold expansion and crack opening displacement as a function of applied load.

Jan 1, 2014

By K. V. Phani Prabhakar, G. Padmanabham1, L. Subashini

Laser-arc Hybrid Welding (LAHW) is a relatively recent concept which effectively combines the advantages of laser welding such as the high depth of penetration, low heat input, high welding speed and the positive aspects of arc welding such as better edge bridging and possibility to add filler. For example, steel sections upto 12 mm thickness have been successfully welded in a single pass at a welding speed of 1 m/minute using a 3.5 kW CO2 laser in combination with a MIG arc. Maraging steel of grade M250 is widely used in the aerospace industry in thicknesses upto 10 mm. Conventionally, it is possible to MIG weld such thicknesses in 3-5 passes employing V-Groove joint preparation. However, this multi-pass welding results in formation of reverted austenite in the weld zone after post weld aging; and the high heat input widens the reverted austenite containing heat affected zone which is popularly known as the dark zone/eyebrow zone. Both these zones are detrimental to strength of the welded joint, specifically the fracture toughness. The width of the dark band is an important factor because, thinner the band, it is supported more effectively by the surrounding material. Therefore, in order to avoid multi-pass welding and reduce the overall heat input, single-pass laser-MIG hybrid welding was attempted on 10 mm thick maraging steel M 250 plates using a hybrid laser arc welding system comprising a 3.5 kW CO2 slab laser and a MIG welding system. Simultaneously, multi-pass MIG welds also are produced. Both the laser-MIG hybrid and MIG welds are characterized microstructurally and subjected to mechanical tests such as tensile and fracture toughness in as-welded and post weld aged condition. The amount and distribution of reverted austenite in the fusion zone and width of the dark band was found to be different. Hybrid welds showed a narrow dark band zone and improved mechanical properties. Laser-hybrid and MIG welding investigations carried out on thick section maraging steel M 250 will be presented in detail, including microstructure, tensile properties and fracture toughness of the welds. To the best of the knowledge of the authors there are no reports on laser-MIG hybrid welding of maraging steels.

Jan 1, 2014

By Son Hye Jin

Abstract ? KHNP is participating in the construction of Nuclear Power Plant both in Korea and UAE. ? We want to improve our construction project management process. ? So we are now developing the process model on nuclear power plant construction management. ? For the effective adoption of this process, we are planning to develop IT system. ? For the first step, we were established the Information Strategy Plan

Aug 1, 2013