Search Documents

By J. Wong, M. G. Lipsett, L. K. Daneshmend

"Current trends of increased size, complexity, and automation of surface mining equipment necessitate more comprehensive and objective techniques for equipment comparison and selection. The field of reliability analysis provides tools to generate quantitative bases for maintenance and reliability aspects of such comparisons. Results from statistical analyses of failure and repair time data are used to perform the comparison. A case study is presented which analyzes five machines of two different technologies and three different designs.IntroductionThe surface mining industry is currently faced with a rapid evolution in production equipment. The more obvious trend in this evolution is the steady introduction of even larger machines. Parallel, and complementary, to this increase in size is the introduction or adaptation of new technologies. Together, these two trends result in new surface mining equipment designs; these designs are often more complex and may feature technologies that have yet to be proven for the application or at the scale they are now fielded.The prospect of significant automation of open pit equipment is also bound to add complexity to future equipment designs. Semi-automated features, such as drilling controllers (Aquila, 2000), have already been commercialized. Fully autonomous haul trucks have been demonstrated in open pit mines (Jackson and Zoschke, 2000). Design concepts for comprehensive teleoperation of open pit operations have been formulated (Lipsett, 1998).With this rapid availability and deployment of new technology and equipment, managers and maintainers are faced with a multitude of decisions regarding what equipment to acquire and what maintenance strategies to implement. In light of this evolution in mining equipment, it is necessary to develop better methods for making equipment management decisions (Dessureault et al., 1999; Paraszczak, 1999). The incentive for development of such techniques is that a large portion of an open pit mine’s operating cost is maintenance related, as shown in Table 1."

Jan 1, 2000

By S. Klingmann

ABSTRACT In this paper, we used data collected from the Gibraltar mine to analyze the effect of the TyreSense tire monitoring system on tire performance by reducing tire wear and preventing premature tire failure or damage. We analyzed the relationship between tire temperature, tire pressure, and tire failure or damage to help better understand the importance of controlling high tire temperature and pressure. The results enhance and expand the knowledge of the management of tire operational pressure and temperature.

Jan 1, 2014

By T. Ivankina, T. Lokajícek, H. Kern, T. Svitek

The knowledge of 3D velocity distribution of P- and S-waves in rocks is very important parameter for interpretation and understanding the nature of seismic anisotropy observed in the earth’s crust and upper mantle. A new high-pressure measuring head was designed and constructed to enable ultrasonic sounding of spherical rock samples in 132 independent directions under up to 60 MPa of acting hydrostatic pressure by means of simultaneous longitudinal and transversal sounding. New measuring system enables ultrasonic sounding of spherical rock samples by using a pair of P-wave sensors and two pairs of perpendicularly polarized S-wave sensors (TV and TH) see Fig.1. Shear wave sensors polarization is oriented according to rotation axis of the sample. Special shear wave gel was used to transfer shear waves between the sample and sensors under acting hydrostatic pressure. An isotropic glass sphere was used to check and calibrate the new measuring setup. A spherical sample of a biotite gneiss from the Outokumpu scientific drill hole was used for testing measurement. There is shown that both, P- and S-wave velocities, can be measured simultaneously up to 70 MPa, respectively. We report data of the 3D velocity distribution of P- and Swaves measured for the first time on a sample sphere of biotite gneiss. We rely, in particular, on the directional dependence of compressional and shear wave propagation and their relationship to the crystallographic (CPO) and shape preferred orientation (SPO) of major rock-forming minerals. The 3D seismic measurements revealed a strong foliation-related directional dependence (anisotropy) of P- and Swave velocities. Ultrasonic measurements were compared with 3D velocity calculations based on neutron diffraction measurements of crystallographic preferred orientation (CPO) of major minerals. Comparison of 3-D velocity distribution (P, S1, S2 and S1-S2) determined by two completely different methods ultrasonic sounding and neutron diffraction is presented. Measurements showed that the intrinsic bulk anisotropy is basically caused by the CPO of biotite constituting about 23 vol.% of the rock.

Jan 1, 2015

By R. W. Boyle

"EDITOR'S NOTEPart 1 of this paper, published in the August issue, covered lithochemical surveys based on major, minor and trace elements in whole-rock samples from primary enveloping halos.Part 2, which follows, continues with discussions of surveys based on leakage halos, zonation of elements, stable and radioactive isotopic distributions, and geothermometric, geobarometric, thermoluminiscent, pedochemical, hydro-chemical, atmochemical and biogeochemical methods. It concludes with a selected bibliography.Surveys Utilizing Leakage HalosLeakage halos can be used as scalar or vector quantities in thesearch for deeply buried blind mineral deposits. In the first case, the occurrence of a leakage halo (e.g. a small pitchblende seam) may simply indicate the possible presence of pitchblende mineralization or orebodies; in the second case, the areal or three-dimensional distribution of leakage halos may, by their increasing frequency and I or increasing metallic or gangue element content, provide a means of vectoring in on loci of mineralization and orebodies. Examples of both cases are given in the following text.Leakage halos are of many types, as shown in Figure 2 (Part 1), and are best discussed with respect to their associated mineral deposits. Furthermore, it should be noted that leakage halos are frequently offshoots or extensions of enveloping halos. Where this occurs, careful tracing of the leakage halo(s) downward or upward respectively will often lead to the apex or nadir (bottom) of the enveloping halo(s) and ultimately to mineralization or ore."

Jan 1, 1982

The Mineral Industry of Canada in 1951 Continuance of the remarkable, successive increases in the value -of Canada's mineral production, chief basis of the nation's post-war expansion, was one of the highlights of Canadian development in 1951, when, according to the preliminary estimate is-sued by the Dominion Bureau of Statistics and reported in the BULLETIN for February, 1952, mineral output for the year reached a new high of $1,228 millions. This marked an increase of 17.5 percent over the previous year, which was the first in which the billion dollar mark had been reached, and an increase of 143.7 per cent over 1946, when production was valued at approximately $503 millions. While higher prices for the principal base metals accounted for a large part of the 1951 increase, quantity gains were made by copper, nickel, zinc, asbestos. lead, cement, and strikingly important. by petroleum, the value of which exceeded for the first time that of coal production. Gold was an exception to the general trend, being lower in both quantity and value than in 1950. For the first time nickel .came within $9 millions of surpassing-gold as the leading mineral product. Metals and Fuels The value of all metals, estimated at $733 millions, was 18.7 per cent more than in the previous year. Nickel advanced 11 per cent in volume and 34 per cent in value. Copper was up 2.4 per cent in quantity and 21 per cent in value, zinc rose 6.6 per cent in quantity and 35 per cent in value, and although the volume of lead produced was lower by 8 per cent, its value increased by 17 per cent. The tonnage of iron ore was 31 per cent higher than in 1950.

Jan 1, 1952

By Guy Archambault, Réal Daigneault

"Un trait marquant du cadre tectorwstratigraphique de la Sous-province de l'Abitibi est la présence de nombreux couloirs de déformation d’extension régionale et sub-concordants au grain stratigraphique. La présence de grandes masses granitoïdes qui perturbent l'allure du grain tectonique est typique de la partie nord de la Sous-province de l'Abitibi. Des rides E-W constituées de complexes plutoniques précoces forment des reliefs structuraux agissant comme des moles résistants qui interfèrent avec la déformation régionale.Deux types de couloirs de déformation sont distingués, les couloirs de bordure et les discontinuités structurales. Les couloirs de bordure représentent des auréoles de déformation élevée qui s’accompagnent généralement d’un métamorphisme au faciès amphibolite. lls suivent /'interface entre les roches granitoïdes et les assemblages supracrustaux. Ces couloirs sont de puissance kilométrique et sont confines, surtout au sein des roches vertes, a l’interface des complexes granitoïdes d’importance. La limite entre la Sous-province de l'Opatica et les roches supra crustales de l'Abitibi est caractérisée par un important couloir de bordure issu possiblement d'un chargement tectonique irrégulier et concentre lors du raccourcissement horizontal.Les discontinuités structurales sont des failles ductiles qui se propagent surtout en direction E-W mais avec des variantes de directions SE et NE. Les discontinuités E-W se caractérisent par la présence d'une linéation d'étirement à fort angle de chute. Les discontinuités SE sont caractérisées par des linéations d'étirement horizontales et directionnelles et les mouvements observes sont system attiquement dextres. Les discontinuités NE sont des failles à comportement beaucoup plus fragile et se distinguent par des composantes de mouvement senestre. Elles sont tar dives par rapport aux discontinuités E-W et SE et ne représentent pas la symétrique du système SE.La combinaison des systèmes E-W et SE décrit un motif anastomose a l' échelle régionale. Les failles ductiles se rejoignent defaçon asymptotique, isolant des blocs peu ou pas affectes par la déformation. L'anastomose est un phénomène qui se produit a toute échelle et est reliée principalement aux Mt érogénéités et aux anisotropies 1) des forces agissantes (champs de contraintes régionale et locale) et 2) de la réponse del' empilement supra crustal (compositions différentes, fabrique initiate, propriétés mécaniques variées, niveaux d'altération).Dans le but de respecter un raccourcissement horizontal N-S, différents modelés sont proposés; ils mettent en cause soit une transpression dextre, soit des failles inverses réactivées en failles décrochèrent dextres soit des failles de chevauchement redressées."

Jan 1, 1990

By Sukumar Bandopadhyay, Arunapuram Sundararajan

"Unique production and environmental problems are associated with multiple seam mining where dragfines are used for overburden and interburden removal. On the production side, the problems are decreased dragfine efficiency in chopdown operations, the general need for spoil rehandle, complications in sequencing stripping and coal handling operations, and potential stability problems in highly stacked spoil. Many variations of dragline methods have been reported in the literature to encounter these problems. Because of the physical properties and peculiar hydrology of sub-arctic region mining of multiple seams in such areas probably could not be done with the methods used in temperate regions.The properties of thawed material would make spoil hard to place in a stable manner and thus would influence the mini sequence. For instance, multiple seam mining which requires some rehandling of spoil and prolonged exposure of overburden and interburden material might be precluded by the instability of thawed spoil and therefore mining techniques have to be modified. Since the deployment and operation of a dragline in modes different from conventional schemes will affect productivity, it will be necessary to study the effects on production of changing the dragfine operational schemes. This paper presents a heuristic simulation model of multi-seam dragline operation of a sub-arctic mine that can be used to analyze the handling of overburden and detailed study of the dragfine performance."

Jan 1, 1986

By R. E. Whitehead, G. J. Prior

"Abstract -Biotite from aplite that appears to have crystallized simultaneously with disseminated Cu-Mo mineralization at MacLeod Lake in northern Quebec yields K-Ar dates in the range 2032 ± 44 Ma to '2f1:)1 ± 47 Ma. The mean value, 2065 Ma, is some 400 Ma younger than the 2485 ± 64 Ma date obtained from a hornblende concentrate separated from a granodiorite sill that is spatially, but apparently not genetically, associated with the disseminated Cu-Mo deposit. The mean biotite date of 2065 Ma at MacLeod Lake, a K-Ar date of 2055 Ma reported from an area 50 km east of MacLeod Lake and published dates of about 2000 Ma for galenas from the Chibougamau Cu-Au ores, suggest a widespread thermal and mineralization event, in that part of the Superior Province east of James Bay, that differs from the common late Archean mineralization that is related to volcanism and metamorphic-intrusive activity.Sommaire - Les datations au K-Ar sur des biotites qui auraient cristallisé en même temps que la minéralisation disséminée en Cu et Mo dans une aplite mise en place au Lac MacLeod, au nord du Québec, s'échalonnent entre 2032 ± 44 Ma et '2f1:)1 ± 47 Ma. La datation moyenne, soit 2065 Ma, est d'environ 400 Ma plus récente que la datation obtenue pour un concentré de hornblende extrait d'un fùon-couche de granodiorite qui est spatialement mais ne serait pas génétiquement as­ sociée à la minéralisation disséminée en Cu et Mo. La datation moyenne de la minéralisation au Lac MacLeod, soit 2065 Ma, la dataion au K-Ar à 2055 Ma citée pour une région à 50 km à l'est du Lac MacLeod, de même que les datations d'environ 2000 Ma établies pour des galènes qui se trouvent dans le minerai aurifère et cuprifère à Chibougamau, suggèrent un phénomène thermique répandu qui aurait produit la minéralisation dans cette région à l'est de la Baie James, dans la province du lac Supérieur. Ce phénomene serait différent de celui qui aurait produit la minéralisation répan­ due d'âge archéen tardif qui elle serait associée à l'activité volcanique et à l'activité intrusive accompagnée de métamorphisme."

Jan 1, 1992

By A. G. Mattes

This paper presents an overview of passive, engineered, biologically-based anaerobic bioreactor (ABR) treatment systems of the sort that can be used to remove dissolved copper from mine wastewaters. The paper begins with a brief history of the origins of this treatment technology and continues with a discussion of principles of engineered wetlands (EWs, advanced kinds of constructed wetlands, CWs) and the use of vertical sub-surface flow (VSSF) varieties that contain pulp & paper biosolids as the reactive medium for EW cells. A brief outline of a procedural methodology used in evaluating the potential for biological treatment on a site-specific basis is also included. An introduction to the microbiology of passive biologically-based treatment systems is followed by some recent research results in the general area of wetlands and ABR research. The paper concludes with a brief discussion of several sites known by the authors to have successfully (or not) demonstrated the potential of this treatment option.

Jan 1, 2007

By Philip Thwaites

"Automatic flotation control in varying degrees of sophistication is practiced at a number of concentrators throughout the world. Practically, the variable conditions in the flotation circuit and the difficulty in maintaining accurate instrumentation information all add to the complexity of automatic control.Further development at the Kidd Creek concentrator has resulted in a 3075 mtpd copper flotation circuit capable of running twenty-four hours a day under the direct control of an optimizing supervisory computer.Three main streams, continuously monitored by an XRF analyzer, supply circuit information to the optimizing computer. Circuit efficiency calculations (from smelter contract terms) and target setpoints allow the computer to determine the economic optimum direction to move the circuit based on the grade/recovery relationship. Circuit manipulation is accomplished by precise pumping of collector and frother reagents together with accurate control of flotation bank pulp levels. The former uses computer controlled diaphragm pumps and the latter is achieved by control loops utilizing a float type level transmitter, variable position dart plugs and a process computer working to setpoints determined by the optimizing computer.The development of a fully automated flotation circuit is by no means complete, but increased knowledge and major hardware improvements have allowed its progression to a higher level of sophistication.IntroductionThe Kidd Creek concentrator is located twenty-six kilometers east of Timmins, Ontario, within a metallurgical complex including a 109,000 mtpy zinc plant and a 59,000 mtpy copper smelter and refinery. The concentrator treats two ore types, a copper-zinc ore and a copper-silver-Iead-zinc ore, at a combined rate of 4,500,000 mtpy. Flotation of the crushed and ground ore yields copper and zinc concentrates from the copper-zinc ore and copper, lead and zinc concentrates from the copper-silver-lead-zinc ore."

Jan 1, 1983

By Unkown

To the Membership of the Institute Gentlemen: The Mineral Industry of Canada in 1948 The preliminary estimate issued by the Dominion Bureau of Statistics and tabulated in the Bulletin of January, 1949, indicated that the value of Canada's mineral production in 1948 reached an all-time high of $808,180,216, showing an increase of 25 per cent over the previous record of $644,696,007 established in the preceding year. The output value of metallics was increased by 22.4 per cent; of fuels, by 43.7 percent of other non-metallics, by 19 per 'cent; and of structural materials, by 16.8 per cent. The value of metals produced in 1948 at $483,770,759, was about $87,000,000 more than in the previous year. There were substantial increases in the tonnages of copper, lead zinc nickel, and other base metals produced, but the rises in market prices for such metals accounted for most of the gains in output values. Production of gold at 3,495,403 ounces valued at $122,339,105 indicated an increase in volume of approximately 500,000 ounces and an increase in value of 14 per cent. Despite the benefits provided under the Emergency Gold Mining Assistance Act 1948 the volume of gold produced in the year was still nearly 2,000,000 ounces less than the record of 5,300,000 ounces established in 1941. The value of mineral fuels produced in 1948, at $158,787,255, was 44 per cent above the 1947 total. Coal production at 18,431,250 tons valued at $107,298,757, while substantially higher than in the preceding year was still half a million tons below the record reached in 1942. Striking developments in the Leduc field in Alberta were responsible for bringing the output of crude petroleum in the year to a new high of 12,098,166 barrels, valued at $36,858,959.

Jan 1, 1949

By R. Gatzweiler

The Key Lake nickel-uranium deposits are situated within the Wollaston domain of the Churchill structural province. The host rocks of the two orebodies are of Aphebian and Helikian age. The orebodies occur mainly within a 5.2-km-Iong, northeast-trending zone which coincides with the intersection of the sub-Athabasca unconformity and a reverse fault striking east-northeast. The principal controls of mineralization are structural and lithostratigraphic (i.e., post-Athabasca faults, the sub-Athabasca unconformity and graphitic metapelites in the lower Aphebian, close to the Aphebian/Archean unconformity). Grades of up to 35% U3O8 and 20% Ni are recorded over intervals of up to 2 m. Some hypogene zonation exists and the nickel mineralization tends to underlie the high-grade uranium ore. The ore minerals include pitchblende, a-U307, coffinite, gersdorffite, millerite, niccolite, bravoite, zoisite, sericite, chlorite and kaolinite. The kaolinite is a post-ore, supergene alteration product. Chemical studies of the sub-Athabasca paleo weathering profile sho w that regolithization is characterized by depletion in Si02 and K20 and concomitant enrichment in Al203 and perhaps MgO. In the paleoweathering profile the ferromagnes ian minerals are chloritized, the Ksfeldspars sericitized and the plagioclase saussuritized. Preliminary geochronologic data from the ores reveal U/Pb ages of -1228 my, - 960 my and 89 my, and Rb /Sr data indicate basement ages of -1850 my and - 1372 my. Aphebian pelitic protoliths, carrying U and Ni, may have released some metals during post-Hudsonian weathering, and minor concentration in structural and geochemical traps may have taken place prior to the deposition of the Athabasca strata. However, it is felt that the bulk ofthe ore-grade mineralization wasgenerated after the deposition of the Athabasca formation and after faulting, probably during a major regional thermal/ intrusive episode of Grenvillian age. Several episodes of remobilization took place between 1228and 89 my ago.

Jan 1, 1979

By Michel Dagbert, Mohammed Harfi

"Abstract - The Draa Sfar polymetallic deposit, at about 16 km NW of Marrakech in Morocco, is a massive sulfide zone at the contact between an underlying volcanic and an overlying clastics sequence. The mineralized body is a flat lens with schistosity and "boudinage," tilted to the west and with a strong dip to the east. The lens extends over a strike length of about 2 km and from surface to a depth of about 1 km, with thickness varying from 1 m to almost 30 m. It has been intersected by about one hundred surface drill holes and, in its south part, by about thirty underground fan holes from two exploration levels at depths of 300 m and 400 m. On these two levels, the massive sulfide zone has been channel sampled over a cumulative length of about 0.7 km. Results from drill and channel samples are used to estimate the resources of the orebody according to several methods: sections, polygons around intercepts on a longitudinal plan, grids on the same longitudinal plan with various distance weighting methods including kriging and, finally, a 3D grid with the same range of interpolators. A comparison of the various estimates delineates the important factors in deriving resources for this type of deposit. Those factors are mostly geological and related to the interpretation of the geometry of the two limiting surfaces of the zone. For the 3D gridding, the authors have devised a new and original method that constrains the interpolation of blocks from samples to a geometry of limiting surfaces. The resulting model shows internal grade variations that parallel fluctuations of zone thickness and orientation without having to re-orientate the search window in each block. Résumé - Le gisement polymétallique de Draa Sfar, situé à environ 16 km au NW de Marrakech est un horizon de sulfure massif au contact d’une formation volcano-sédimentaire de base et d’une formation détritique sur-jacente. Le corps minéralisé se présente sous forme d’une méga-lentille aplatie, schistosée, boudinée et déversée vers l’ouest avec un fort pendage vers l’est s’étendant sur une longueur de 2 km et une profondeur de près de 1 km avec une épaisseur variant de moins d’un mètre à près de 30 m. Il a été reconnu par plus d’une centaine de sondages de surface et, dans sa partie sud, par une trentaine de trous souterrains en éventail à partir de deux niveaux à des profondeurs respectives de 300 m et 400 m. Sur ces mêmes niveaux, des traçages ont permis de rainurer le minerai sur une longueur cumulée de 0.7 km. Les données de sondage et de rainurage ont servi à estimer les ressources du gisement selon plusieurs méthodes : sections, polygones sur longitudinale, grille sur longitudinale avec différentes pondérations en fonction des distances incluant le krigeage et enfin grille tridimensionnelle avec le même éventail de pondérateurs. La comparaison des estimés obtenus permet de mettre en évidence les facteurs importants dans l’estimation des ressources de ce type de gisement. Ces facteurs sont essentiellement géologiques et relatifs à l’interprétation de la géométrie des limites des corps minéralisés. Pour l’estimation sur grille tridimensionnelle, on a mis au point une technique originale qui calque l’interpolation des blocs à partir des échantillons sur cette géométrie des surfaces de contact. Le modèle résultant montre des variations internes de teneurs qui épousent les fluctuations d’épaisseur et d’orientation de la zone sans qu’il soit nécessaire de ré-orienter les fenêtres de recherche dans chaque bloc."

Jan 1, 2002

By B. Tonn, F. Kröger

"The continued development in engine technology is leading to an augmentation in power density which steadily elevates the requirements for thermally and thermo-mechanically highly loaded components such as cylinder heads and pistons. Due to these high performance requirements conventionally applied Al-Si alloys have reached their application limits, since their mechanical properties deteriorate quickly under the influence of heat. Improved applicability is given by Al-Cu-based casting alloys which have a superior high-temperature strength than Al-Si alloys. Since Al-Cu alloys exhibit insufficient casting characteristics, especially regarding hot tearing susceptibility and increased tendency for porosity, it is currently not possible to cast geometrically complex components in robust permanent mold casting processes. The further development of Al-Cu alloys is aimed at finding an optimum between improved castability while high-temperature strength and thermal conductivity are not deteriorated. It is known that a high amount of eutectic reduces the hot tearing susceptibility of an alloy, but it reduces thermal conductivity at the same time. In this paper it will be presented how the conflicting objectives – improved high-temperature strength, good thermal conductivity and reduced hot tearing susceptibility – can be brought together to develop an optimized Al-Cu alloy for application in permanent mold casting.INTRODUCTION At the beginning of the 21st century car, engine blocks were primarily made of gray cast iron (GJL). Less than half a decade later, the choice of material had shifted towards lightweight materials. Ever since, the car engine manufacturing is dominated by aluminum-based alloys. The weight of car engine blocks could thus be reduced by around 50% due to the lower specific weight of aluminum alloys compared to gray cast iron. Furthermore, the high thermal conductivity of aluminum alloys allowed a reduction of complex cooling channel systems and thereby promoted the advancement of this material group. The further development in engine technology leads to an augmentation in power density which elevates the requirements for thermally and thermo-mechanically highly loaded components. For example, in diesel-powered car engines the upper required limits can reach an ignition pressure as high as 230 bar and gas temperatures of up to 1000°C. Thereby, thermal loads can cause high alternating thermal stresses (Grzincic, 2003) which can effectively be reduced by providing high thermal conductivity."

Jan 1, 2017

By Marcondes Lima Costa

The Amazon region is characterized by the development of deep chemical weathering represented by widespread lateritic covers and soils. Two distinct periods of laterite formation can be distinguished: mature laterites from the Eocene-Oligocene (and locally from the end of the Cretaceous), and immature laterites from the Pleistocene. The older laterites occur on plateau landscapes,and the younger ones on widespread hilly to ?at lowlands. Both types show complete or truncated pro?les, generally covered by deep yellow to brown topsoils. The mature laterite pro?les contain high concentrations of gibbsite and/or aluminum phosphate, whereas the immature ones are poor in these minerals. The Amazon region is rich in mineral deposits related to lateritic pro?les. Some mineral deposits are of primary origin but were concentrated to economic grades by lateritic processes. The most important ore deposits are of iron, aluminum (bauxite), kaolin, manganese, gold, nickel, copper and phosphate. These are mainly related to mature pro?les. The wide spectrum of ore deposits and mineralogical and geochemical complexity of the Amazon laterites has been promoted by: (1) the prevalence of ideal conditions for laterite formation throughout much of the Tertiary; (2) the presence of varied basement lithologies due to contrasting geological environments; and (3) a variety of epi-genetic alteration types. The lateritic pro?les show a well-developed ore zonation which is related to speci?c lateritic horizons. Iron and gold deposits occur in the ferruginous horizon, which is nearest the surface; the central aluminous horizon hosts bauxites, aluminum phosphate, strontium and gold;and the lower clayey horizon contains deposits of manganese, nickel, copper and kaolin. Resistate phases which residually accumulate throughout entire pro?les include titanium (as ilmenite andanatase), chromium (as chromite), tin (as cassiterite), yttrium (as xenotime), and niobium (mainly asilmenorutile). Epigenetic alteration, caused by swamp environments developed above truncated lateritic pro?les, has led to the formation of high-grade kaolin and refractory bauxites. The laterites inthe Amazon region contain most of all known kinds of ore mineralization related to laterite processes.

Jan 1, 1997

By Marcondes Lima Costa

Abstract-The Amazon region is characterized by the development of deep chemical weathering represented by widespread lateritic covers and soils. Two distinct periods of laterite formation can be distinguished: mature laterites from the Eocene-Oligocene (and locally from the end of the Cretaceous), and immature laterites from the Pleistocene. The older laterites occur on plateau landscapes, and the younger ones on widespread hilly to flat lowlands. Both types show complete or truncated profiles, generally covered by deep yellow to brown topsoils. The mature laterite profiles contain high concentrations of gibbsite and/or aluminum phosphate, whereas the immature ones are poor in these minerals. The Amazon region is rich in mineral deposits related to lateritic profiles. Some mineral deposits are of primary origin but were concentrated to economic grades by lateritic processes. The most important ore deposits are of iron, aluminum (bauxite), kaolin, manganese, gold, nickel, copper and phosphate. These are mainly related to mature profiles. The wide spectrum of ore deposits and mineralogical and geochemical complexity of the Amazon laterites has been promoted by: (1) the prevalence of ideal conditions for laterite formation throughout much of the Tertiary; (2) the presence of varied basement lithologies due to contrasting geological environments; and (3) a variety of epigenetic alteration types. The lateritic profiles show a well-developed ore zonation which is related to specific lateritic horizons. Iron and gold deposits occur in the ferruginous horizon, which is nearest the surface; the central aluminous horizon hosts bauxites, aluminum phosphate, strontium and gold; and the lower clayey horizon contains deposits of manganese, nickel, copper and kaolin. Resistate phases which residually accumulate throughout entire profiles include titanium (as ilmenite and anatase), chromium (as chromite), tin (as cassiterite), yttrium (as xenotime), and niobium (mainly as ilmenorutile). Epigenetic alteration, caused by swamp environments developed above truncated lateritic profiles, has led to the formation of high-grade kaolin and refractory bauxites. The laterites in the Amazon region contain most of all known kinds of ore mineralization related to laterite processes.

Jan 1, 1997

By L. V. Chugaev, Y. M. Shneerson, P. V. Zaytsev, I. V. Fomenko, M. A. Pleshkov

"Pressure oxidation (POX) is one of the most common and reliable methods of processing gold-bearing sulfide concentrates. However, when processing concentrates that contain natural carbonaceous matter, substantial gold losses occur due to autoclave preg-robbing. The latter involves formation of gold chloride complexes under typical POX conditions (high temperatures, high acidity and high ORP) and subsequent sorption of these complexes by carbonaceous matter. Naturally, chloride ion plays a significant role in the process of autoclave preg-robbing; its concentration in POX solution has a well-marked effect on subsequent gold recovery during cyanidation of POX residue. The previous research done by SRC Hydrometallurgy showed that autoclave preg-robbing of gold could be significantly inhibited by the addition of mercury(II) compounds to POX slurry. The positive effect of mercury(II) was well pronounced both at high (>20 mg/L) and low (<5 mg/L) Cl concentrations in POX solution. The successful bench-scale laboratory testing was followed by pilot plant trials at Ore Test Facility in Blagoveshchensk, Russia. The present paper provides the results of these trials. The bench-scale testing results were verified; the optimum oxidizing parameters and reagent dosage were specified. The behavior of mercury (II) at POX pilot plant was found to be in good consistency with industrial practice described in the literature.INTRODUCTION Pressure oxidation (POX) is one of the most common, reliable, and commercially proven methods of processing gold-bearing sulfide ores and concentrates. However, when processing double refractory materials that contain natural carbonaceous matter, POX technology advantages are compromised by autoclave preg-robbing of gold. The latter occurs when natural organic carbon and soluble halides are both present in autoclave feed. Strongly oxidizing conditions of POX (high temperature, oxidation-reduction potential or ORP, and acidity) favor formation of gold-halide (mostly, gold-chloride) complexes, which tend to bond with carbonaceous matter. The exact nature and mechanism of this bonding is unknown, but as the result of this, cyanide is unable to leach gold from POX residue and the precious metal is lost to the tails (Axenov et al., 2014; Dimov, Chryssoulis, & Sodhi, 2003; Fomenko, Zaytsev, Pleshkov, Chugaev, & Shneerson, 2013)."

Jan 1, 2017

By A. J. Stapleton

"The Copper Mountain mine of Gaspe Copper Mines, Limited was brought into production in January, 1968.This paper describes the organization, scheduling and control of maintenance of large open-pit equipment, including 8-cu.yd shovels and 85-ton electric-wheel haulage units. The facilities for repair as well as maintenance are also described, including repair shops and field repair equipment. Maintenance costs are discussed and particular reference is made to tire inspection, records and costs."

Jan 1, 1969

By B. Hohenstein, B. McBain, B. de Jong

"The automated fire assay system (Fast In-line Fire Assay or FIFA) has not found acceptance in the Au mining industry as the lower measurable limit of 0.20 ppm did not allow Au tailings to be measured with confidence. The development of arrested cupellation has overcome this hurdle which was a limiting factor in the FIFA 1 process. In the new automated fire assay process, automated sample preparation, fluxing, fusion and separation of a Pb button are essentially similar to the FIFA 1 process, albeit with some improvements. However, the game-changer is the development and incorporation of arrested cupellation into the automated system, now called FIFA 2. The purpose of arrested cupellation is to reduce the 50 g Pb button to a 5 g Pb button by partial cupellation in a specially developed arrested cupellation system thereby concentrating the Au in the Pb by a factor of 10 and in so doing moving them into higher concentration ranges in the mini-button where they can be read on the spark spectrometer. Results show that concentrations down to 0.02 ppm Au in geological materials can now be determined using arrested cupellation in the FIFA 2 process, an order of magnitude improvement over FIFA 1.INTRODUCTION Traditional fire assay for Au has remained virtually unchanged for 3000 years. It has survived for so long because it is accurate, has relatively low detection limits and is relatively inexpensive. However, it is labour intensive, has a long turn-around time (typically at least 7 hours), is environmentally unfriendly and exposes assay operators to potentially unsafe conditions (toxic fumes, toxic dust and extreme heat from furnaces). The NiS collection method is not as effective for the assay of Au as it is for the PGEs. A rapid, accurate, cost-effective method for the determination of Au and the Platinum Group Elements (PGEs) in geological materials would be a tremendous benefit to mining companies. Many of these objectives have been met by the FIFA 1 (Fast In-line Fire Assay) developed some 15 years ago in which automated methods have replaced the manual procedures which are part and parcel of conventional fire assay. However, concentrations below 0.2 ppm have been very difficult to achieve with sufficient reliability."

Jan 1, 2017

By J. O. Pitts

"Background The preponderance of Canada's coal resources is located in areas remote from high demand domestic users and at some significant distances from deepsea ports. This places great demands on the transportation system and has forced the coal and the transportation industries to adopt highly efficient methods of handling the product and hauling it to market position. Most of the coal not consumed in minemouth thermal power stations is carried by rail over lines operated by the two transcontinental railway systems, Canadian National and Canadian Pacific. These rail networks are extensive and have the advantage (as compared to most other North American railways) of being able to handle coal movements from origin through to destination without interchange to other rail carriers. Coal SourcesWith exception of the coal produced in Cape Breton, Nova iScotia, all the significant shipping volumes in Canada emanate ifrom mines located in the three most westerly provinces. Figure I ishows the geographic distribution of the major mining operaitions shipping coal to domestic and export markets. The prinicipal routes and the tonnages carried (1980 calendar year) are ialso indicated. iThe 1980 shipping data are summarized in Table I. Saskatchewan lignite began moving from Bienfait to Thunder Bay by CP Rail unit trains in mid-1981 at the rate of one million tonnes per year. The product is handled through Thunder Bay Terminals and delivered directly to a nearby Ontario Hydro electrical generating station."

Jan 1, 1985