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By Raj Thamburaj

"Over the last few decades, the emphasis on affordability and reduced cost of ownership has necessitated the development of innovative processes to carry out repairs in aero engine components. Conventional weld and braze repairs have evolved into advanced, sophisticated processes using state of the art knowledge in lasers, robotics and materials technology. This paper illustrates past and present scenarios in an attempt to illustrate progress that has been made in this area. The problems encountered in the past have been detailed along with the solutions that have been developed and commercially implemented to address these issues. Apart from technical progress, this presentation also addresses the progress made in business approaches and in Certification/Regulatory issues surrounding aero engine repair. Progress in Technology Repair technologies have also been the embryo from which new and revolutionary manufacturing technologies have evolved as well. Electron Beam Free Forming and LENS are examples of how a completely new manufacturing concept can evolve what was originally only a process to join metals. The current and future potential of these spin offs is discussed providing examples of application. While several problems have been solved over time with the implementation of advanced repair technologies, the demands of the industry have created new challenges. The paper describes these issues, outlines potential solutions and discusses the future of repair technologies in terms of the far reaching influence it is sure to have in design, manufacturing, maintenance management and life extension. Progress in Business Trends.Business approaches to repair and maintenance have also gone through considerable change with the introduction of ""Power by the Hour"" and other similar arrangements between the companies responsible for engine overhaul and the end-users. Program Based Logistics (PBL) is yet another innovation to provide a win-win situation for the repair service provider and the end user. This paper traces the development of these business initiatives and highlights successful applications. Progress in Repair Certification, Regulatory Issues.Understanding of the issues surrounding certification of repairs has also evolved with time and regulatory issues have been clarified considerably. Procedures for analysis and testing are much clearer and ""Check Lists"" are being drafted for certifying repairs on various engine components. The PMA phenomenon has added yet another dimension to the issues regarding certification and these are discussed as well."

Jan 1, 2010

By R. D. Brown

Ever since British Columbia started the ball rolling in 1974 with the introduction of its now-defunct Mineral Royalties Act, all Canada's resource-based provinces have significantly altered their mining tax systems. The last resource-based province to abandon its pre -1974 mining tax structure is New Brunswick, which introduced a new mining tax regime in the summer of 1977 to take effect from April 1 1977. The new structure, which represents the outcome of considerable study and discussions with industry representatives, contains some intriguing concepts which make Nero Brunswick's new mining tax system unique among the Canadian provinces.

Jan 1, 1977

By BARRY BANNATYNE

Ombrotrophic Sphagnum peat bogs have a characteristic signature on both colour injrared film (750 nm to 3,000 nm response) and Daedalus injrared line-scanner images (thermal infrared 3 to 5 microns and 8 to 14 microns response). This remote sensing method was used to survey bogs in southeast Manitoba to delineate targets for surface exploration. Target bogs all have a surface growth of Sphagnum; underlying dead Sphagnum ranges from 1 to 6 m thick. Large Sphagnum reserves exist in the Caribou cluster of bogs, and in /979 a bog first identified by infrared sensing was brought into production.

Jan 1, 1984

By F. A. Charalambous

Brannerite is commonly referred to as a refractory uranium mineral as it is usually highly resistant to acid leaching. There is however widely varying literature data on brannerite leaching, with some studies reporting that brannerite leaching can be achieved under relatively mild conditions. The differences observed for brannerite leaching are most likely due to the high degree of variation in the composition and structure observed in natural brannerites. These aspects of brannerite chemistry however are not very well understood due to a lack of fundamental research. The aims of this study were to investigate and develop methods for synthesising brannerites of varying composition and to investigate the effects of composition on brannerite leaching in acidic conditions.

Aug 1, 2010

By A. Tohn, L. May, Adham. K.

The path from process conception to commercial implementation poses significant technical, economic, and sometimes political challenges for every project team. Solving the technical challenges typically distinguishes successful projects from those that fail. Here, the authors provide an outline for technical success based on lessons learned from years of experience in process design and R&D. Challenges faced by new technology developers, with regard to design and definition, are described. Experience-based methods to avoid missteps are shared. Special emphasis is placed on the selection of viable unit operations, definition of known and unknown parameters, experimental screening of options, and piloting for scalable design information. Use of computational models to define, assist, and interpret the pilot operations and results are described. Furthermore, the value of active collaboration amongst the design, research, and owner team is demonstrated.

Jan 1, 2011

By P. Plante

Contaminated neutral drainage (CND) is characterized by the presence of metal concentrations above regulatory requirements at circumneutral pH in mine drainage. The generation of CND by tailings and waste rocks is a growing concern for the mining industry due to increasingly restrictive regulatory requirements. Difficulties in CND prediction arise from the low oxidation rates of sulfide minerals and from the metal retention potential within the wastes. In fact, sorption phenomena may induce an important delay in the development of CND. For now, it is not possible to adequately consider this delay using the prediction tools developed for acid-mine drainage, such as humidity cells, columns and lysimeters. This work aims to present the new approaches currently under study for CND prediction, particularly the use of a chelating agent in kinetic tests. The main challenge of CND prediction is to quantify the metal retention potential of mine wastes, especially when sorption phenomena are involved in metal retention. Three approaches are currently used to overcome this difficulty. Firstly, the sorption potential is estimated using batch sorption studies. The second approach consists of artificially saturating the sorption potential of the mine waste by contact with a contaminated leachate in sorption-enabling conditions until saturation of the retention potential. These approaches both require that the possible metals involved in CND are known (as well as their chemical speciation) prior to the tests, which require an exhaustive material characterization. Although the two methods enable a qualitative estimation of the retention potential of mine wastes, their results are difficult to scale up from the laboratory to the field since some important parameters are not taken into account. A third proposed approach consists of inhibiting metal sorption at the source using chelating agents. The hypothesis is that chelating the metals immediately upon their release from the oxidation of sulfide minerals will inhibit all geochemical interactions (sorption, complexation, secondary mineral precipitation, ion exchange, etc.) between the metal and its environment. The ideal chelating agent will inhibit geochemical interactions after metal release in the drainage waters without having any impact on the sulfide oxidation and acid neutralisation rates. These approaches were tested over a waste rock sample that is known to naturally generate CND after a few decades of weathering. Results show that kinetic testing (weathering cell, ± 70 g samples) using a chelating agent (EDTA) in the leaching water renders higher metal concentrations in the leachates than a control sample without EDTA, suggesting that sorption (and possibly other geochemical interactions) is inhibited. These results suggest that the combination of these approaches can be efficiently used for more precise CND prediction from mine wastes. Future work will be done using the chelating agent approach over larger scale tests such as columns (± 80 kg samples) and field cells (± 100 tons) in order to propose an integrated approach for CND prediction.

Aug 1, 2013

By K. E. Haque

"Radium is selectively leachable from uranium ores with various types of lixiviants. Among a number of lixiviants tried on Midwest Lake uranium ore, KCl provided the highest per cent of radium extraction (60%-65%). Leach results further confirmed that a certain portion of Ra is not amenable to KCl leaching. More than 99% of the dissolved radium could be removed by treating the KCl leach liquor with barite or with radium selective complex resin (XFS-43230 resin of Dow Chemical Inc.) or by precipitating as RaBaSO4. Uranium leachings from the Ra-preleached uranium ores indicate that radium leaching prior to uranium may be applied as an extension to the conventional or alternative (i.e. acid chloride) leaching process of uranium ores in order to yield environmentally acceptable tailings (in terms of radium in the solids).IntroductionAt present, radium is considered as an environmental issue, particularly for uranium ore mine mill operations, rather than a commercial commodity. Radium was once a highly priced commodity ($180/mg during the first great war) but now it hardly has any commercial value. Its principal applications were in the field of cancer treatment and in the manufacturing of lwninous dials for watches. Nowadays readily-available synthetic radioisotopes are finding applications in place of radium.Because of scarcity and high toxicity, further commercial applications have never been explored.Radium was first discovered and extracted from uranium ore by P. Curie, M. Curie and G. Bement in 1898. Radium is widely distributed in nature but in exceedingly minute quantities. It is one of the daughter products of uranium or thorium and its maximum concentration is 3.3 x 10-7 part/part of U(21). Because of its short half-life (approximately 1620 years) in a geological time scale, its occurrence in nature as a distinct mineral is most unlikely.The details of the original radium leaching process developed by the Curies and Bernont are in the literature. This process essentially involved the roasting of uranium ore with caustic. carbonate followed by sulphuric acid leaching. The precipitated RaSO4 and BaS04 were treated with boiling Na2CO3 to convert them into the corresponding carbonates which later were dissolved in HCI. RaCI2 and Ba02 were separated and concentrated from the chloride liquor by fractional crystallization. But, in the course of time several modifications were made or proposed to the original process. Regardless of the process employed 226Ra extraction from the uranium ore was seldom better than 90%, and further as much as 20% 2URa loss took place during the concentration and purification process."

Jan 1, 1987

By F. Parada L

Two copper concentrate with medium and high enargite content were leached in a 3 L autoclave reactor under conditions based on the CESL process. Copper, arsenic, sulfur and iron were checked in all the experiments and antimony, zinc and molybdenum were evaluated in selected tests. The 98% of the obtained copper extraction is agree with others authors, but the behavior of arsenic, iron an sulfur have some differences. The solid residue was characterized by chemical analysis, DRX and QEMSCAN®. Finally a comparative analysis with neutral roasting as an option for the treatment of this concentrate is done.

Jan 1, 2014

By R. Thierbach, W. Kahnt, Oberthür. T., D. Eisenburger, V. Gundelach

ABSTRACT: The ground penetrating radar (GPR) method was used in a platinum mine in Zimbabwe by members of the Federal Institute for Geosciences and Mineral Resources (BGR). The measurements were carried out in boreholes and drifts. Electromagnetic re?ections from a fault that consistently trends parallel to the mineralization zone permitted the mapping of the economically minable parts of the deposit. An introduction is given to the geology of the studied area and the application of the GPR method. The electrical parametres of the rocks are measured in situ, the GPR measurements are displayed with radargrams, and the visible structures are explained in illustrations.

Jan 1, 2010

By R. J. Bowell

Mineralogical controls exert significant control over the extraction of uranium from its ores. Uranium speciation, associated mineralogy, deportment and uranium mineral availability are all factors of consideration when assessing leachibility. This study presents data from laboratory uranium extractions undertaken on several contrasting uranium ores from a wide range of orebodies. The results provide insight into the mineralogical factors of importance when considering uranium extraction. These results are presented within the wider context of geometallurgy and demonstrate how geometallurgical assessment, even at an early stage of mine development, can greatly assist in the design of a suitable extraction scheme.

Aug 1, 2010

"The South African Mineral Resource Committee (SAMREC), a Working Group of the SAMREC/SAMVAL Committee (SSC), under the joint auspices of the Southern African Institute of Mining and Metallurgy (SAIMM) and the Geological Society of South Africa (GSSA) developed the SAMREC Code. The Code sets out minimum standards, recommendations and guidelines for public reporting of exploration results, mineral resources and mineral reserves in South Africa. It is applicable to the reporting of all styles of solid mineralization or economic deposit. However, certain commodities, namely coal and diamonds, have specific additional reporting requirements. The Code does not apply to oil, gas or water."

Jan 1, 2003

By P. W. Waggitt

ABSTRACT From approximately 1986 until 2000, uranium production was at a historic low. In 2003, uranium mineral exploration surged, despite the global financial crisis; however, the shortage and aging of qualified and experienced operators and regulators might soon become a constraint to this upsurge. This is true for all types of engineers, geologists, other scientists, tradespeople, and technicians. The situation raises questions about how the global mining industry in general and the uranium sector in particular will cope with future staffing needs. In this paper, the author examines the current situation and describes how some organizations are seeking possible solutions.

Jan 1, 2014

By David G. Dixon, Ahmad Ghahremaninezhad, Edouard Asselin

"Atmospheric leaching of chalcopyrite in sulfuric acid solutions is a slow process due to the mineral’s passivation. We have investigated the nature of the passive film in this work. Electrochemical reduction and oxidation of chalcopyrite over the potential range of -0.5 to 1.2 VSHE were investigated in 0.5 M sulfuric acid solution (pH 0.3) at 25 ºC by multicyclic voltammetry and open circuit potential measurement. The influence of scan limits on the evolution of current peaks was studied with both stationary and rotating electrodes. It was observed that the anodic oxidation of chalcopyrite begins at potentials above 0.6 VSHE, most likely by preferential dissolution of iron atoms over copper atoms. The selective electro-dissolution process results in formation of a metal-deficient sulfide passive film (i.e. Cu1- xFe1-yS2, y > x). The passive film dissolves at 0.9 VSHE. Elemental sulfur is one of the products of chalcopyrite dissolution above 1.0 VSHE. Cathodic reactions within the potential region of 0.1 to 0.6 VSHE and anodic reactions at potentials lower that 0.5 VSHE are associated with at least one soluble species from solution. The soluble species involved in the cathodic reactions are likely ferric and cupric, while the soluble species involved in the anodic reactions is likely H2Saq."

Jan 1, 2014

By Yongfeng Jia, Shaofeng Wang, Danni Zhang

Arsenic in mineral processing solutions and effluents is commonly removed and immobilized via iron(III)-arsenatecoprecipitation. The effect of re-crystallization of 2-line ferrihydrite on the long-term stability of iron(III)-arsenate coprecipitate is still not fully understood. This work investigated the redistribution of arsenic and iron during 2-line ferrihydrite transformation at different pHs and temperatures over time. X-ray diffraction (XRD), transmission electron microscopy (TEM) and chemical extraction were employed to characterize the crystallinity of the iron oxyhydroxides. Results showed that the amount of arsenic released into solution during aging increased significantly with increasing media pH.

Jan 1, 2014

By D. Sammut, F. Houllis, J-L. Huens, J. Moyes

The Intec Gold Process has been developed as a halide-based alternative for the recovery of gold from refractory sulphide deposits. The halide medium allows sulphide oxidation and gold extraction to be performed concurrently at moderate temperature and atmospheric pressure sourcing oxygen from direct air injection. The dissolved gold is loaded onto activated carbon and stripped in a conventional Zadra circuit. High gold extractions have been achieved from a range of refractory gold concentrates at laboratory scale, which has led to a continuous locked-cycle pilot plant program. The pilot plant operated at >99% availability, with a maximum of 96.5% gold extraction from a concentrate containing 58.6 g/t gold. >99% of the dissolved gold was loaded onto carbon at up to 1% w/w, with no loss of carbon activity detected over five loading/washing/elution cycles. This paper describes the process and presents both laboratory and pilot plant results as well as economic data from two costing studies.

Jan 1, 2005

By Peter A. Witt

Highland Valley Copper is a conventional truck-shovel mining and flotation concentrator operation located some 75 kilometres southwest of Kamloops, B.C. (Figure 1). The ore is within a porphyry deposit and is mined at a rate of 135,000 metric tonnes per day from two separate open pits. The nearby mill produces concentrates containing 375 million pounds of copper and 5 million pounds of molybdenum metal yearly. Head grades are roughly 0.40% Cu at a 0.23% Cu equivalent cut-off. The strip ratio currently sits at 0.55:1 with waste quantities made up of separate rock and unconsolidated overburden units. From the mill, concentrates are trucked to nearby Ashcroft and then hauled by rail to ocean port facilities in Vancouver. The mine employs 950 persons and is planned to operate until 2009. The operation is a partnership between three owners: TeckCominco (61.4%), BHP Billiton (33.6%), and Highmont Mining (5%). Management is shared by the two principal owners and directed by an appointed committee.

May 1, 2002

By R. Therrien, L. Gosselin, J. Raymond

ABSTRACT: The ground-source heat pump is a low-carbon technology that uses the earth’s renewable geothermal energy to heat and cool buildings, with an ef?ciency 3 to 4.5 times that of conventional systems. These high performances are achieved by exchanging heat with the earth using a ?uid that is groundwater, surface water or closed loop water. Expensive installations, such as water wells or buriedcoils, are however necessary to transport the ?uid in and out of the earth, making ground-source heat pumps more costly than conventional systems. Installation costs can be reduced in mining environments due to the abundance and the accessibility of resources to be used with heat pumps. Examples of system design calculations using data from the Mouska and Doyon mines in Abitibi show signi?cant installation cost savings using dewatering mine water or ground heat exchangers installed below oxidizing waste rocks. Ground-source heat pump technology is reviewed and scoping calculations are presented to illustrate how such systems can be installed in mining environments.

Jan 1, 2010

By H. Bannach

"This paper focusses on what seem to be the leading indicators of prosperity in the minerals industry during this decade: the geographical distribution of deposits, environmental impact, capital allocation and acid consumption. There is a potential for meeting environmental criteria at a reasonable profit margin, but those with limited acid demand within economic range will face hard times to meet growing environmental concerns, resulting in additional mine closures. At the other end, those with old waste dumps who are thinking about smelting capacity additions will need capital influx at a much larger rate than ever before. All things considered, a change should be made in the way the world's copper reserves are computed, because there is a growing need to internalize these effects back to the ore blocks before a meaningful estimate of reserves becomes available.IntroductionThe copper industry has undergone several changes during the past decade, many of which were expected to take place because they rel1ect the economics of ageing mines. However, many others took place that shocked the industry because they were not completely under control. The focus of this paper is to rel1ect on those changes, and on market expectations for this decade that somehow depend on their impact.To review the prospects for new mine developments and expansions from an industry perspective to a full extent, it would be necessary to consider not only the deposits themselves, but also geographical constraints, environmental constraints, labour composition, technology development and use, the availability of capital, ownership issues, and integration within the industry. This paper, however, will concentrate on only some of the key elements that are believed to playa major role in shaping the market in the decade that has just begun. These elements, all interconnected, are:"

Jan 1, 1992

By S. K. Paul

"This paper briefly describes the underground crushing and conveying system at Sherritt Gordon Mines' Ruttan Mine. A series of three steel-cord belted conveyors, with a total length of 2J55 metres and a total vertical lift of 407 metres, convey the muck from the underground crushing station to the mill at the surface. The maximum size of the crushed rock is 6 in. All the conveyors are provided with numerous safety and fire suppression devices. IntroductionThe Ruttan Mine of Sherritt Gordon Mines Limited is located 20 km east of the town of Leaf Rapids, 760 km north of Winnipeg. The orebody is multilensed, with lens width varying from 6 to 45 m. Ore production started in 1973 with the opening of a 10,000-tpd open-pit mine. Initial development of the underground mine was started in 1972 with the driving of parallel conveyor and access declines at minus-2507o gradient to the I 220-m level, and then the access ramp was further extended to the 1160-m level. Exploration drifting was done on the 1280-m and 1160-m levels from the access ramp. The final development plan for the underground project was approved in January 1977, and full-scale development and constructionwere resumed.At present, Ruttan Mine is in a period of transition from open-pit to underground mining. Ore production is now coming from both operations. By mid-1980, open-pit production will cease and all production will come from the undergroundmine.The underground mining method at the Ruttan Mine is sublevel open stoping with delayed backfilling. The orebody is divided along strike into a series of 27-m-long stopes and 15-m pillars, both 60 m high."

Jan 1, 1980

By Michael J. Sapko, Ellsworth R. Spencer, Frank J. Perzak

"The fire resistance of several mine conveyor belts is evaluated using a new belt-flammability apparatus developed by the U.S. Bureau of Mines. The test apparatus, experimental details and a calculated flammability index (FI) are described.The FI values are useful for ranking the fir e resistance of mine conveyor belts. Values are determined using parameters readily measured with thermocouples, high-temperature flow probes and a methane-oxygen torch, all of which are components of the Bureau's new test apparatus. The FI varies directly with the flame-spread rate and the rate of heat release during burning and varies inversely with the critical (minimum) ignitor energy output.The fire-resistance ranking of nine different belt types using this moderately scaled apparatus is compared with available full-scale data on belt fires. This comparison shows that the ranking based on the FI is consistent with the full-scale data.IntroductionFull-scale fire hazard evaluations of mine conveyor belts are not easily related to the properties usually measured in small-scale flammability tests. The inadequacy of small-scale belt fire tests has been demonstrated in works by Mitchell, Warner and Reinke.Mitchell and Warner showed that certain neoprene (NP) and polyvinyl chloride (PVC) belts, which had been approved by the Code of Federal Regulations 30 CFR 18.65, were nevertheless capable of propagating flame over their entire length when full-scale fire conditions were simulated. Comparable results were also observed by Reinke at the Tremonia experimental mine in Dortmund, West Germany, where all belts burned in full-scale tests even though they passed the small-scale tests. Only by reducing the severity of the full-scale test could these fire-resistant belts be grouped on a pass-fail basis."

Jan 1, 1982