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By G. Bonin, A. Jamal, G. Preciado, S. Gillis

"Accurate, easy to obtain, and reliable methods of measurement are the cornerstone of shaft and tunnel developments - during their sinking, operation and maintenance, or in some cases, remediation. This paper presents a new methodology to capture existing shaft conditions in such a manner that they can be transferred from the field to a digital copy, where they can be stored and used for engineering design purposes in a space not directly affected by the costs associated with schedule and equipment performance. The methodology utilizes basic principles of excavation alignment (plumb lines and survey instruments) while adding modern LiDAR, geolocation and survey control tools that can more completely capture the surrounding environment. The complete cycle of collection, processing, and delivery of pertinent information underground can take under an hour. During sinking, capturing data as a live stream measurement and being able to assess the alignment of the shaft liner can be critical to meeting rigid design tolerances. As sinking progresses, small changes in alignment or liner deviations can be captured and immediately corrected. Likewise, post-construction as-built conditions can be recorded and digitized, which will allow the mine personnel to compare the proper working condition to the actual condition years later. Observed changes can be identified and planned as future shaft repair works. This methodology has been developed and successfully deployed during the on-going sinking works of the two shafts at the Jansen Potash Project in south-central Saskatchewan and is described in greater detail in this paper.INTRODUCTION Light Detection and Ranging (or LiDAR) scans of the BHP Jansen Production and Service shafts during construction identified sections of both shafts where the internal radius of the temporary primary liner was insufficient to accommodate the tolerances of the permanent liner that was to be installed inside the temporary liner. These locations are referred to as “tights”. The “Tights Removal Program” was designed to collect high resolution point clouds of the shaft, using stringent survey control, that could be compared to the design profile to generate a heat map of locations for removal of up to 75 mm of steel-fiber-reinforced, 70 MPa concrete liner. This work was all on critical path, which made it valuable to save time on the schedule. Because concrete removal was a time-intensive task, it was essential to locate and remove only the concrete that would encroach on the planned permanent liner, while attempting to maximize the amount of cutting time. Removal was carried by a road header attached to a Brokk(R) 160, a small multi-attachment demolition machine."

Jan 1, 2019

By M. Ataee-pour, S. E. Jalali

So far, a large number of algorithms have been developed for the optimization of pit limits, most of which follow deterministic rules. In this paper, a new algorithm is introduced, which follows a probabilistic logic using the Markov chain process. The algorithm is implemented on a transition matrix that corresponds to the 2D conventional economic block model of the mining area. The probability of mining a block is proportional to the desirability it may provide. Applying this algorithm, the probability of mining each block is obtained, and finally, the optimum pit limits are defined as the pit, which provides the highest probability of mining. In order to validate the proposed model, a numerical example is given and the results of the algorithm are compared to those of a dynamic programming algorithm. A 2D analysis of the problem is discussed in this paper. Although dealing with 3D problems requires larger size matrices, the optimization method is the same and the algorithm does not need any smoothing.

Jan 1, 2006

By D. Ingram

"PRIMARY DUST COLLECTOR A. 42,000 CFM James Howden Fan Z-6 Size 3650 Fan Dia 40"" HP 75It was found that the fan was not large enough to remove the air that was displaced by the trucks dumping. So it was removed and an enclosure was installed to isolate the gyro from the rest of the building.B. FANSJames Howden Fans Model RPM 3500 Series 357 FW HP 10These fans were installed when the first dust system was put into operation. It was found that the high RPM and extreme fan wear caused a major maintenance problem. These fans were replaced with Chicage Blowers Model SWS1 RPM 1180 Dia 36"".DRY CYCLONE COLLECTORS A.,Three four foot rubber lined cyclones. Four six foot rubber lined cyclones.All under flow. Water is controlled manually and gravity flows to a central sump box. From there it flows to the grinding circuit in the Mill.Cyclone under flow product runs between 100 and 200 tons of dust per 24 hours with a screen analysis 30% + 400.The cyclone under flow product is diluted to about 3 to 4%. Solids total gallonage approximately 400.B.,Elbair Wet Scrubber125 HP RPM 56042,000 CFM,Model PX861The Elbair collects the total product from the discharge. Of the Cyclone fans the under flaw goes to the Mill - the Elbair discharges stack goes to atmosphere.The Elbair wet scrubber had to be redesigned in order to keep it in service."

Jan 1, 1976

By K. G. Thorne, D. R. Lentz, A. F. Park

"The Main zone of the Clarence Stream gold deposit is hosted by a shear zone adjacent to the Saint George batholith in southwestern New Brunswick. The mineralization history relates to progressive deformation in the shear zone and the intrusion of the Magaguadavic granodiorite.Of three phases of deformation that have affected the area (D1-D3), D1 is not observed in the Clarence Stream shear zone. Two suites of igneous rocks intrude the shear zone: post-D2, pre-D3 gabbro; and granitic dikes, which crosscut the gabbros. Granitic dikes show a diverse range of relationships to D3 features, from pre-syn-D3 mylonitic fabrics in transposed and highly deformed enclaves, to nondeformed and entirely discordant dikes (post-D3).A variety of veins occur within this shear zone. Zoisite-bearing and later, crosscutting epidote-bearing veins are preserved as relics in quartz-mylonites, and predate quartz veins that host gold mineralization. The epidote-bearing veins are associated with pseudotachylitic cataclasite dikes, consistent with transient brittle failure during ductile deformation.Deformation relates to right-lateral strike-slip motion across the shear zone, and subhorizontal and near-vertical stretching lineations imply transpression. A late (late- or post-D3) dip-slip phase of motion is also apparent, and cooling followed a metamorphic peak early in D2-D3 history. Deformation of the shear zone, and more localized transient brittle failure, provided the permeability for fluid movement and vein emplacement. This scenario is similar to the findings of other studies, in which geochemical, tracer isotopic, and age-dating (U/Pb, 40Ar/39Ar) results suggest that the adjacent Magaguadavic granodiorite provided heat and metals. La zone principale (Main zone) du gisement d’or de Clarence Stream est encaissée par une zone de cisaillement qui longe le batholite de Saint George dans le sud-ouest du Nouveau Brunswick. L’historique de la mise en place de la minéralisation accorde un rôle important à la déformation progressive dans la zone de cisaillement et à la mise en place de la granodiorite de Magaguadavic.Des trois phases de déformation à avoir affecté la région (D1-D3), les effets de D1 ne sont pas observés dans la zone de cisaillement de Clarence Stream. Deux suites de roches ignées se sont mises en place dans cette zone de cisaillement : un gabbro post D2, pré-D3 et des dykes granitiques qui recoupent le gabbro. Les dykes granitiques montrent une grande diversité de relations avec les structures D3, allant de précoces à synchrones aux fabriques mylonitiques D3 dans des enclaves transportées et fortement déformées à des dykes complètement discordants et non déformés (post-D3).On note diverses veines dans cette zone de cisaillement. Des veines contenant de la zoisite ainsi que des veines d’épidote sécantes plus tardives, lesquelles sont préservées comme reliquats dans les mylonites à quartz et sont plus vieilles que les veines de quartz contenant la minéralisation aurifère. Les veines d’épidote sont associées à des dykes de catacalasite à texture de pseudotachylite, compatibles avec une rupture cassante épisodique durant la déformation ductile.La déformation résulte d’un mouvement décrochant dextre le long de la zone de cisaillement et les linéations d’étirement subhorizontales et quasi-verticales impliquent de la transpression. Une phase tardive (tardi- ou post-D3) de mouvement selon le pendage est aussi apparente, et le refroidissement succède à un pic métamorphique tôt dans l’histoire D2-D3. La déformation de la zone de cisaillement et la rupture cassante épisodique ont fourni la perméabilité nécessaire au mouvement des fluides et à la mise en place des veines. Ce scénario est similaire à celui proposé par d’autres études, dans lesquelles les résultats de géochimie, de traceurs isotopiques et de géochronologie (U/Pb, 40Ar/39Ar) suggèrent que la granodiorite de Magaguadavic avoisinante a fourni la chaleur et les métaux."

Jan 1, 2008

By P. Diehl, M. David

"As shortage in the supply of mineral commodities become more probable, there is an increasing need for reliable and comparable reserve/resource data. It is therefore necessary to standardize the traditional classification procedure by quantifying the three basic criteria in resource evaluation: economic feasibility, geologic assurance and recovery. For the portion of fairly well documented deposits and as far as their geologic parameters are concerned, geostatistical methods can considerably improve the quality of ore classification. In respect of economic feasibility and recovery, approved geostatistical methods can be introduced directly into the classification procedure. The concept of geologic assurance, however, requires a new interpretation in terms of geostatistical error spread. As the ""risk"" in estimating an ore parameter is also a function of the respective block size, it is reasonable to define not only upper limits for the risk intervals for each class of uncertainty, but also block dimensions which reflect the typical stage of planning associated with the different ore categories. An algorithm has been developed to block out areas inside a mine or a large panel which satisfies the constraints of an ore category in respect of the risk intervals of a parameter and in respect of their size. The method has been computerized and is demonstrated on a massive copper-nickel deposit.IntroductionFacing an uncertain future with respect to the demand and supply of mineral commodities, both governmental authorities and the mining industries show an increasing interest in a useful framework for the assessment and classification of the remaining mineral resources"". This is reflected by the recently published appraisal and classification scheme of the United Nations as well as by the new or revised classification systems of the USA; Canada or Australia. Moreover there are various classification schemes which are currently discussed in major mining companies."

Jan 1, 1982

By A. D. Akerman, D. D. Young, G. R. Baiden

The development and maintenance of underground roadways are increasingly important aspects of the modern mining process. With the trend toward automation and track-less mining, roadbeds capable of with standing increased wheel loading have proven necessary to maintain high vehicle speed and reduced maintenance costs. Concrete has been used successfully on some roadways in order to obtain the required characteristics. However, this solution usually involves unacceptable expense. The objective of the Road Router project was to create a drift floor profiling machine capable of cutting a smooth surface out of the existing rock floor of development drifts and ramps. This surface would provide a durable, high strength, low rolling resistance roadbed that would allow for reduced operating cycle times and lower maintenance costs of scoops and haulage trucks. The Road Router has the potential to offer an alternative to concrete with substantial cost savings.

Jan 1, 1997

By X Dai

This paper investigated the loss of cyanide via oxidation in CIP or CIL processes by relating the cyanide oxidation to its major oxidation product, cyanate. The results showed that the oxidation of both free cyanide and copper cyanide complexes are substantially enhanced by the presence of carbon. The rate of cyanide oxidation was found to occur in the order: Cu(CN)32- > CN- > Cu(CN)2-. The cyanide oxidation rate in the presence of copper and carbon increased significantly with increasing dissolved oxygen concentration, typical of CIL vs. CIP conditions. Cyanide oxidation rate of iron, zinc or nickel cyanide complexes was minimal.

Jan 1, 2011

By C. Hudson, D. Tremblay, A. Frey

"A discussion of the design, challenges and successes associated with the commissioning of the gravity recovery circuit at Canada’s newest open pit gold mine - Atlantic Gold’s Moose River Consolidated Project in Nova Scotia, Canada is presented. An overview of the project, its historical significance and overall flowsheet is provided with special focus given to the design and selection of the gravity circuit equipment including the scalping screen, gravity concentrators and the novel intensive leaching technology selected for the project. The performance of the gravity circuit is benchmarked against the feasibility study process design specifications and the outcomes are discussed. Challenges encountered during commissioning are also presented, including the use of third-party automation and the effects of screen sizing on overall gravity circuit performance. Mechanical modifications made to the Sepro Leach Reactor for the Moose River project are also discussed. A detailed technical review of the mechanical and operational aspects of the Sepro Leach Reactor is provided with key operational data on leach times, recoveries, reagent usage, solid-liquid separation, pregnant solution quality and its influence on bullion purity.INTRODUCTION Atlantic Gold Corporation’s Moose River Touquoy Mill in Nova Scotia, Canada was commissioned in the fourth quarter of 2017 with commercial production declared in March of 2018. The 2 Mtpa process plant uses a conventional, gravity-CIL process. This site was previously mined in the 1870s. Interest waned in the early 1900s but resumed in the 1930s and the mine was brought back into production in 1935 until an underground mine collapse in 1936. This mining district became famous after CRBC radio commenced a ground breaking, around the clock, broadcast of the rescue operations. Over 100 million people listened to the broadcast from Canada, the United States and the United Kingdom. These broadcasts changed radio, transforming it from a medium for music to on the spot, breaking news reporting. The mill was constructed by Ausenco on a fixed price EPC contract in the historic Moose River gold mining district, 95 km north-east of Halifax by road. The mill will process ore from the adjacent Touquoy pit for the first 5+ years of operation; after the Touquoy reserves are exhausted, the mill will process ore trucked 37 km from the Beaver Dam deposit for an additional 5 years."

Jan 1, 2019

By Minghao Hu, Hongbo Zhao, Jun Wang, Wenqing Qin, Rui Liao, Central South University

"In the present work, X-ray diffraction (XRD) analysis, X-ray photoelectron spectroscopy (XPS) analysis and electrochemical analysis were carried out to investigate the intermediate species and electrochemical dissolution process of chalcopyrite in the presence of sulfur and iron oxidizing microorganisms. For bioleaching of chalcopyrite by the sulfur oxidizing microorganism Acidithiobacillus caldus, the redox potential was always lower than the appropriate value and chalcopyrite was mainly directly oxidized to polysulfide (Sn 2-), thus resulting in low copper extraction. As for bioleaching of chalcopyrite by the iron oxidizing microorganism Leptospirillum ferriphilum, chalcopyrite was mainly directly oxidized to polysulfide at the initial stage where redox potential was lower than the appropriate value and resulted in low dissolution rate. At the middle stage where redox potential was appropriate (about 350–480 mV vs. Ag/AgCl), chalcopyrite was mainly transformed to intermediate species of Cu2S rather than polysulfide, thus resulting in high dissolution rate. At the later stage where redox potential was higher than the appropriate value, chalcopyrite was mainly directly oxidized to polysulfide which caused the later passivation of chalcopyrite. Finally, a model of electrochemical dissolution process of chalcopyrite in the presence of sulfur and iron oxidizing microorganisms was provided.INTRODUCTIONBiohydrometallurgy is considered as one promising mineral processing technique in processing low grade ores due to the advantages of simplicity, low cost and eco-friendly. Chalcopyrite (CuFeS2) is the most abundant copper-bearing resource, accounting for appropriately 70% of the known reserves in the world, while is recalcitrant to bio-hydrometallurgy mainly due to the coated passivation layer (Klauber, 2008; Li, Kawashima, Li, Chandra, & Gerson, 2013). However, the detailed dissolution and passivation mechanisms of chalcopyrite bioleaching are still uncertain. The microorganisms assisting chalcopyrite dissolution can be mainly classified into three types, including mesophilic microorganisms (e.g., Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans and Leptospirillum ferrooxidans), moderately thermophilic microorganisms (e.g., Acidithiobacillus caldus, Sulfobacillus thermosulfidooxidans and Leptospirillum ferriphilum), and extremely thermophilic microorganisms (e.g., Metallosphaera sedula, Sulfolobus sp., Acidianus sp., and Sulfurcoccus mirabilis). Moderately thermophilic microorganisms have a better prospect in the future industrial application of chalcopyrite bio-hydrometallurgy (Olson, Brierley, & Brierley, 2003; Rohwerder, Gehrke, Kinzler, & Sand, 2003). Hence, investigating the detailed dissolution and passivation mechanisms of chalcopyrite bioleaching by moderately thermophilic microorganisms is of important significance, which will provide essential information for promoting chalcopyrite bioleaching by moderately thermophilic microorganisms in laboratory or industrial plant."

Jan 1, 2016

By William Pitman

Ground instability and subsequent rock falls are a major concern in underground mines. As a result, several mining companies are conducting risk assessments of the ground support installed in their mines. Risk assessment is now commonly used to provide mine operators with a systematic process to assess the strategic risks that could lead to injury to personnel or loss of production, and evaluate possible risk control measures. Risk assessments can be carried out to identify major hazards, assess the likelihood of occurrence and consequences of each hazard and estimate the level of risk. This process allows assessment of possible remediation actions to minimize the risk and likelihood of occurrence or mitigation of the consequences to a level that is reasonable and practical. This paper presents two practical mine applications of qualitative risk assessment of ground support to highlight the benefits of this process. Yearly or bi-yearly risk assessment of mine excavations can assist mine operators in prioritizing resources and areas that require support remediation. In addition, it provides a mechanism for proactive response to reduce potential risks associated with personnel safety, equipment safety and environmental impact. It also provides a baseline against which changes in ground condition can be compared and quantified.

May 1, 2004

By Colin Lindsay

"The Collahuasi copper mine, located at an altitude of 4300 meters above sea level in northern Chile, commenced operations late in 1998. The mine is currently the 4‘h largest copper producer in the world and comprises an open pit, a 60,000 tpd sulphide concentrator, a 15,000 tpd oxide heap leach and SWEW plant and a 200 km concentrate pipeline to a port facility.Constructing, commissioning and operating a mine at high altitude presents unique challenges in terms of the performance of both equipment and people. It is important that these be recognized and carefully considered during the feasibility study and the detailed design stages and the success of the Collahuasi project is largely due to this. The plant design incorporates a number of features aimed at mitigating the problems of altitude and the construction methodology also took into account the particular site conditions.This paper discusses the Collahuasi project team’s approach to planning for the remote location and also some of the problems experienced during construction, commissioning and operation.INTRODUCTIONThe Collahuasi mine is located in northern Chile, some 250 km to the south-east of the port of Iquique and 15 km from the Bolivian border. The mine facilities lie between 3800-4300 m above sea level on the Altiplano, the central plateau of the Andes mountains, and cover a total of approximately 95,000 hectares. Although the area is arid, it experiences an average of 150 mm of precipitation annually and weather conditions can be extreme. Temperatures during the day range between -3 to +11 º C and are generally below 0ºC at night, sometimes as low as -20°C. High energy winds are common and humidity is low. Much of the precipitation occurs during the winter as snow but there also occurs a period during the Chilean summer known as the “Invierno Boliviano’’ (or Bolivian Winter) which is characterized by severe electrical storms and rain."

Jan 1, 2001

By H. B. Merlin

"The past demands for energy and the contributions by the major sources are shown for the world and regions, and for Canada. Three forecasts of future demand are presented. By the year 2000, the world will be consuming energy at a rate of 670-700 x 1015 Btu/year. Canada's rate is estimated at 20 x 1015 Btu/year. Electricity will increase its portion of energy from 7.5 per cent to 15 per cent, and more than 40 per cent of the primary energy w1ll. be required to generate 1t. World, regional and Canad1an forecasts are g1ven for total electricity generated and for electricity generated in nuclear stations. The integral world requirement for energy by the year 2000 will be over 12 x 10 18 Btu. Current recoverable fossil and hydro reserves are about 18 x 1018 Btu. The total reserves are estimated to be seven times greater.World production of electricity in nuclear stations by the year 2000 will be almost three times the electricity produced in the world today. The amount of fuel consumed in generating this electricity will depend upon the types and mix of reactors installed. The heavy water reactors, alone or in conjunction with fast breeders and liquid fuel reactors, are the most efficient users of uranium and thorium resources. The heavy water reactors are also the most efficient producers of plutonium which will be required as fuel for fast breeders."

Jan 1, 1969

By V. Vorontsov

Catalysts Mo-Ni-S were prepared by combining MoS2 and NiS in weight ratios 1:1, 1:2, 1:4 and 2:1, each of which was admixed with 5%wt Ag and 5%wt YSZ to increase three-phase boundary surface area of the electrode. For comparison catalysts comprising Co-Mo-S in weight ratio of 1:1 of CoS to MoS2 admixed with 5%wt Ag and YSZ and pre-sulfided NiMoO4 were made. The catalysts were examined for electrochemical oxidation of hydrogen sulfide in solid oxide fuel cells (SOFC) at 850°C temperature. The catalyst prepared from 1:1 (wt. %) NiS:MoS2 demonstrated highest performance. Current density up to 1,330 mA/cm2 and power density up to 300 mW/cm2 were achieved using pure H25 gas, which are the highest among the reported H2S-powered fuel cells ever published in the literature. Anode materials of different NiS:MoS2 ratios have been characterized by means of X-ray diffraction (XRD), simultaneous TG/DSC analysis and Neutron Activation Analysis (NAA). TG/DSC and NAA results show that addition of NiS and Ag increases fuel cell performance due to improved structure/integrity of the anode. It has also been demonstrated that MoS2 is a suitable anode material in H2S-powered SOFC, with high activity towards H25 oxidation and thermally and chemically stable up to 850°C.

Jan 1, 2005

By K. Purazrang, P. Musavi Garavi, P. Sh. Naseri, P. Abachi

The fracture behavior of high strength Al7050 alloy was investigated at room and elevated temperatures using small size, V-notched tear (called Kahn specimen) and compact tension, CT, specimens, respectively.To study the elastic-plastic behavior of the alloy, the tensile test was also performed on the sub-sized cylindrical tension test specimen. The microstructure of the alloy was examined using optical- and scanning electron- microscopy. The rupture mechanisms and crack path were also studied by examination of specimens' fracture surfaces using SEM. The microstructure examination revealed equiaxed grains and some elongated grains in rolling direction, with the areas of partial re-crystallized grains where coarse intermetallic particles are mostly found.In general, fracture surfaces were indicative of dimpled ductile type. Considering the fractographs of tensile specimens, the void growth mechanism is also dominant in fracture of these specimens. Nevertheless, in some regions, smooth areas can be observed due to the friction during rupture process. The results of mechanical tests at RT made the evaluation of tear strength to 0.2 % tensile yield strength ratio, as a measure of notch toughness, available. According to elevated temperature, 150°C, test results and plots of log da/dt vs. log KI , the crack propagation behavior over discrete ranges of crack growth rates could be assumed linear and then be obeyed as a power law equation in the form of da/dt = A (KI)n .

Jan 1, 2015

By Greg M. Hollyer

The search for minerals in the future will be dominated by deeper exploration and the need to accurately target ?blind? deposits as more and more of the ?easy? near surface targets are exhausted. In this context, key technologies are emerging for deep exploration both in grassroots and minesite exploration, including the Titan 24 Deep Penetrating geophysical technology. Introduced in 2001, this technology has grown rapidly into an accepted approach for exploration in a variety of geologic environments, including brownfield environments where discovering additional reserves would most quickly benefit companies. Titan 24 belongs to a new class of sophisticated Distributed Acquisition Systems (DAS) which record high-volume, high-quality data simultaneously at multiple receiver stations. This data is then processed digitally, modeled using specialized inverse modeling software, and interpreted according to geologic and other parameters. The result is a robust, high-quality, high-volume data sets which provide a basis for improved imaging to depth. In this paper, the Titan 24 distributed technology is discussed. Illustrations of the vast improvement to overall exploration are showcased through results in several case studies. These include examples from two gold deposits, a porphyry deposit and a minesite. These examples show the range of applicability of the technology and the ability to effectively image mineralization, lithology, structure and alteration to depth as an aid to understanding prospective mineral deposits and targeting drills more accurately.

May 1, 2008

By V. J. Sopuck, O. P. Lavin, Ian Nichol

"A major challenge of contemporary exploration geochemistry is the development of procedures that can locate blind mineralization or mineralization that sub-crops below a cover of transported overburden, the composition of which bears no relation to the underlying mineralization. Over the past few years, the possible existence of diagnostic geochemical features in the country rock associated with volcanogenic massive sulphide deposits has attracted increasing attention both on the local mine scale and on the regional scale. In the present investigation, the nature of the geochemistry of a number of Archean greenstone belts of the Canadian Shield is examined to determine the feasibility of distinguishing productive from non-productive areas of copper-zinc mineralization. The results indicate that productive areas are distinguishable from non-productive areas providing consideration is given to the effects of igneous differentiation on rock compositionIntroductionArchean massive sulphide deposits are an important source of copper and zinc, and to a lesser extent silver and gold, particularly in Canada. As in the case of most other forms of mineralization, there is a continual need to develop new techniques that will improve the chances of success in the search for these deposits. The majority of Archean areas in the northern latitudes are overlain by a variable cover of glacial overburden. Considerable progress has been made in the development of new geochemical exploration techniques for use in glaciated terrain, based on the detection of anomalous dispersion in the glacial overburden. In certain situations, however, as in the search for blind deposits or in areas covered by glaciolacustrine deposits, overburden geochemistry offers little hope for success. In the case of massive sulphide deposits, one possible solution may lie in the detection of anomalous geochemical signatures in the bedrock. Recognizing this possibility, attention has been directed to the investigation of the nature of lithogeochemical dispersion associated with massive sulphide deposits on both regional and local scales, to establish the potential of lithogeochemistry as an aid in the search for these deposits."

Jan 1, 1980

By Luke Keeney, Stephen Walters

"The start up of a new mining and metallurgical facility is a crucial step in the life of any mining project. The mining industries record is poor when evaluating processing plant operation relative to design capacity predictions made during feasibility studies. Multivariate geometallurgical orebody characterisation, using principle component analysis, is a method developed for improving predictive processing performance models during feasibility stages of mine development. This paper outlines the application of multivariate geometallurgical characterisation to the Cadia East deposit located in New South Wales, Australia. Cadia East is a low grade high tonnage copper-gold porphyry system in advanced stages of feasibility analysis. A dataset of ~32000 measurements and 150 comminution parameters (A*b and BMWI) has been used to develop class-based characterisation and modelling methodologies. The results of this study outline the development of class-based ore characterisation and provide a technique for analysing and interpreting large and complex geometallurgical datasets for prediction and optimisation of processing performance. The results enable sophisticated population modelling to be conducted which displays deposit scale processing variability, aiding circuit design specifications and predictions during feasibility studies.INTRODUCTIONA feasibility study is the major technical report on which the decision to proceed to production and on which financing is based (Shillabeer & Gypton, 2003). The mining industry’s record is not very good when actual construction time, costs, and operating performance are compared to the projections made in feasibility studies (Ballard, 1983; Gypton & Ward, 2000; Gypton 2002). A study by McNulty (1998) found that of 41 mineral processing and chemical plants built between 1965 and 1995, only 56% achieved design capacity within two years of commissioning and three were closed after failing to achieve design capacity within 36 months of start up (Shillabeer & Gypton, 2003). McNulty (1998) related this underachievement and failure of start up performance to the use of innovative process technology without appreciating and managing technical risk. Factors contributing to technical risk include inadequate pilot plant testing, scaled up prototype equipment without backup, design flaws and poorly understood complex process chemistry."

Jan 1, 2009

By J. Paturaud, A. G. Villemiane, J. Y. Buffiere, D. Fabregue, M. Perrier

In this work, a detailed characterization of the cyclic damage mechanisms on duty in car heat exchangers has been carried out in order to improve their reliability. The material which consists in very thin (<0.3 mm thick) sheets formed of 3 co-rolled aluminum alloys (4045 /3916/ 4045) has been brazed in order to obtain metallurgical and surface conditions representative of those of the real components. Fatigue tests at constant stress amplitude have been performed at room temperature and 120°C in order i) to characterize the cyclic resistance of the studied materials and ii) to study the effect of temperature on the fatigue damage mechanism. The mechanisms leading to failure have been identified from post mortem fractographic analysis. The Wohler curves obtained show that, contrary to common structural Al alloys, this type of thin sheet brazed multi material can be cycled for several hundred thousand cycles at very high stress level (> ~ 80 % of the tensile strength). This behaviour is analysed with respect to the microstructure resulting from the brazing process and the low number of grains present in the sample thickness (around 5 grains).

Jan 1, 2015

This paper presents the results of research aimed at proposing new solutions in the area of belt conveyor elements. Many factors, such as energy consumption costs, and operating costs of belt conveyor elements, including belts, idlers and drives have an impact on the operational costs of conveyors. The paper presents special tests of new materials for the bottom cover of an energy-saving belt conveyor, which decrease rolling resistance. It also presents large-scale in-situ tests of a high-output belt conveyor for the purpose of simultaneous measurements of various types of conveyor belts (standard vs several energysaving types) under typical operating conditions of a lignite surface mine. Improvements in materials used for the bottom belt covers, supported by specially developed comprehensive tests of the new types of belts have provided valuable results of various proposed solutions. Since the tests of belts were done at exactly the same time and in the same operating conditions, direct comparison of the results is valid and should lead to a substantial decrease in the conveyors? drives? energy consumption, which will improve the effectiveness of belt transport and minimize its negative influence on the environment.

Aug 1, 2013

By Shahram Tafazoli

This article presents a novel technology for sensing the size of rocks after blasting in hard rock mines. Blast engineers require rock size statistics to carefully adjust the blasting parameters. The rock fragmentation requirements vary depending on the ore type and crusher specifications. The most popular statistical parameters in the industry are the so-called P numbers (e.g., P80 and P100). A machine vision based system is introduced here for automatic image collection and fragmentation analysis of the material right inside the bucket or dipper of mining shovels. A heavy-duty camera provides the required imaging data to an embedded computer mounted inside the cab. A custom machine vision software continuously analyzes the captured bucket images and stores the suitable ones in local storage which are then fed to a Desktop software for automatic fragmentation analysis. This technology has been developed by Motion Metrics International and is commercially available as FragMetrics?.

May 1, 2009