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By David Sanscartier, Elizaveta Petelina, Alexey Klyashtorin

This paper provides an overview of the radiological risk mitigation approach applied by the Saskatchewan Research Council (SRC) for the remediation of 35 legacy uranium mine sites in northern Saskatchewan where uranium exploration and extraction took place in the 1950–60s. Mining activities resulted in an irregular increase of the gamma radiation dose rate (up to 18 μSv/h). The radiological objectives for the sites include a gamma dose rate at a spot (<2.5 μSv/h above local background), and the dose rate averaged over a hectare (<1 μSv/h above local background). These objectives are generally achievable at the impacted sites through the installation of shielding soil cover. This method may be impractical for site areas with rough terrain (e.g., steep slopes) and/or difficult access. A risk assessment approach is applied to determine if these areas can be safely left uncovered or if additional mitigation measures should be implemented. The risk assessment approach is based on two factors: (i) the ambient radiation dose rates collected through gamma surveys, and (ii) actual land use data collected through various surveys of activities of local community members at the sites. Exposure scenarios based on four land uses are applied to estimate a potential annual dose load for members of the public. The estimated doses are compared with the criterion of 0.3 mSv/a recommended by the Canadian Guidelines for the Management of Naturally Occurring Radioactive Materials (NORM). If the criteria are not satisfied, a mitigation plan is developed, and post-remediation gamma levels are modelled using GIS tools to evaluate the performance of the proposed mitigations. The proposed approach allows the team to optimize resources for the site remediation so that public exposure to NORM are as low as reasonably achievable after remediation.

Jan 1, 2020

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

By G. R. Phare

Explosives formulation is dictated by desired field performance, which in turn is dependent on such physical properties as strength, velocity of detonation, sensitivity, and water resistance. The design of explosives to obtain these properties is discussed with some reference to detonation and rock mechanics theory.

Jan 1, 1958

By Z. D. Hora

Sand and gravel resources of the southern coastal region of British Columbia may be linked to various episodes of Wisconsin glaciation. During Wisconsin and probably earlier times, the Fraser Lowland and coastal areas were subjected to repeated glaciations separated by non-glacial intervals. Each major glaciation was accompanied by isostatic and eustatic changes in sea level up to 200 m or more. As a result, the Lowland was covered by the sea during much of Quaternary time. Because the Fraser Lowland is surrounded on two sides by high mountain ranges, glaciers terminated in the sea during their maximum advance. Therefore, meltwaters released during deglaciation, together wit h retreating glacier ice, could produce widespread and extensive sand and gravel deposits both along the coast and throughout the Fraser Lowland and adjacent areas.

Jan 1, 1984

By Xiaozhu Chen, Qi Ping, Pu Yuan, Qinyong Ma

"In order to investigate the fractal feature of coalmine deep rock fragments under impact loads, variable cross-section split Hopkinson pressure bar apparatus, 50 mm in diameter, was adopted to conduct impact compressive test for rock specimens from -962m deep coalmine. Various impact pressures, such as 0.3, 0.6, 0.9 and 1.2MPa, were selected to implement different loading rates. Sieving statistical analyses were conducted for rock fragments after being impacted, and the particle size distribution of broken rock in various loading rates were calculated with the fractal method and then the corresponding fractal dimension was obtained. Test results shows that there is a good self-similarity and fractal feature in fragments distribution of deep coalmine sandstone under impact loads. The fractal dimension of fragments is between 1.9 and 2.7. The research also indicates that there is an approximate power relationship between dynamic compressive strength and fractal dimension, and a strength power relationship between fractal dimension and average strain rate. Moreover, there is a linear relationship between fractal dimension and specimen absorbed energy. The rock fractured process can be quantitatively described through fractal dimension, which can reflect the deep rock broken degree and is an ideal index to evaluate the distribution of rock fragments.INTRODUCTIONBroken rock is one of the most basic processes in mining operations, rock fragmentation has always been an important index to evaluate rock breaking effect (Xu & Yu, 1984). Macroscopic fragmentation of rock material is the final results of continuous development, expansion, gathering and cutthrough of internal micro-cracks. This process, developing from microscopic damage to macroscopic fragmentation, is an energy dissipation process and shows fractal characteristics (Xie, 1993). Turcotte (1986) has conducted statistical analyses of fragmentation for different kinds of geological materials under various broken conditions, and arrived at the conclusion that fragmentation distribution is a fractal."

Jan 1, 2015

By T. W. Bingay

The production of both lead and zinc in Canada has steadily increased during recent years until today Canada ranks among the world&apos;s leading producers of both of these metals. The high prices which they have commanded have led to an energetic search for new deposits and also to an investigation of abandoned properties which, under the present conditions of better prices and more efficient methods of treatment, offer chances of commercial success. It is confidently expected that during the next few years success in both these lines of activity will further increase Canada&apos;s lead and zinc output, giving her a still higher ranking among the world&apos;s producers. In 1926, approximately 140,000 tons of metallic lead was produced from ores mined in Canada, and of this, 125,000 tons was refined in Canada at Tadanac, B.C. During the same year the production of metallic zinc from Canadian ores amounted to 68,000 tons, of which 62,000 tons was refined at Tadanac. History Of Lead and Zinc in Canada The production of lead in Canada is much older than that of zinc. The chief source has always been the interior of British Columbia. As earl y as the &apos;eighteen twenties&apos;, Indians and Hudson&apos;s Bay Company&apos;s trappers had discovered an outcrop of lead ore on the site of the present Blue Bell mine on the east shore of Kootenay lake, but it was not until1865 that active prospecting for lode deposits began. In the early nineties the activity of the silver-lead-zinc region of the Slocan reached its culmination and a steady production has been maintained down to the present time. Up to the end of 1924 the Slocan area produced over 38 million ounces of silver, nearly 300 million pounds of lead, and almost 122 million pounds of zinc.

Jan 1, 1927

By P. D. S. St. Pierre

IN REGENT YEARS, blast furnace operators have found it necessary to improve their technology in order to handle increasingly low-grade feed and yet satisfy the demands for greater tonnages of metal. Studies have been made covering several aspects of the problem, and in this connection the slags produced in the iron-making process have been critically examined with a view to discovering the slag with the optimum properties for a given operation. A good slag should combine, as far as possible, the properties listed in Table I. Unfortunately, some of these desirable properties are incompatible. For example, the advantage of the small ?bulk of a low-flux slag is offset by its low desulphurization potential and high viscosity. Similarly, a very fluid slag increases refractory wear. It will be seen, then, that a balance must he struck between these conflicting requirements. In the .present paper only the melting relationships of blast furnace slag ?compositions will be considered in detail. In interpreting the data herein presented, the optimum property requirements listed in Table 1 must strictly be borne in mind. It should also be noted that the discussion presented here always relates to calcined fluxes, since this facilitates reference to the final slag composition. Thus, in making calculations pertaining to the ?burdening of the furnace, due allowance should ?be made for the fact that the fluxes are added as carbonates.

Jan 1, 1956

By E. Uzun

"In this study, H2SO4 and HCl leaching behaviour of an ore sample containing 1.87% of Ni, obtained from the Karaçam (Eskisehir-Turkey) lateritic deposit that started operation recently was investigated. Acid concentration, temperature and reaction time were investigated as variables by comparative leaching tests and the optimum leaching conditions were selected on teh basis of Ni, Fe, Co and Mg behaviour. For H2SO4 leaching, optimum leach parameters were 95°C, a 12 normal H2SO4 concentration and 90 minutes of reaction time, and under these conditions Ni and Fe dissolutions were 97.6% and 95.4% respectively. On the other hand, 70°C, an 8 normal HCl concentration and a reaction time of 90 minutes were found to be the optimum parameters for HCl leaching, and Ni and Fe dissolutions found were 97.1% and 97.8%, respectively.INTRODUCTION Today, nickel and various nickel compounds are obtained from sulphide and lateritic nickel ores (Moskalyk & Alfantazi, 2002). Even though about 72% of the world's nickel reserves constitute lateritic ores, only about 42% of nickel is produced from these ores. The decrease in production from sulphide deposits, on the other hand, and increases in the use of nickel in the iron and steel, and battery production sectors, and especially the production of nickel cast irons in recent years, have accelerated the importance of making use of lateritic deposits (Luo et. al., 2010; Chang et. al., 2010). In the beneficiation of sulphide nickel ores, mostly pyrometallurgical methods are used. On the other hand, about 39% of lateritic ores are beneficiated by pyrometallurgical, and 61% are beneficiated by hydrometallurgical methods (USGS, 2009). In laterite beneficiation, the ore properties are of significance; that is to say, limonitic ores are eneficiated by high pressure acid leaching or via the Caron process, nontronitic ores are beneficiated by high pressure acid leaching or heat treatment (smelting), and ores containing serpentine by pyrometallurgical methods (Berezowsky, 2004; McDonald & Whittington, 2008a; Dreisinger et. al., 2015)."

Jan 1, 2017

By S. Makni, S. Koppalkar, A. Bouajila

ABSTRACT This paper briefly reviews the gravity recovery between conventional and centrifugal gravity separators. The advantages of semicontinuous gravity separators will be discussed, as will techniques for upgrading the gravity concentrates. The research efforts in optimizing semicontinuous gravity separators will be recalled. An innovative gravity circuit for eliminating or minimizing the use of complex processing schemes will be reviewed. Ongoing gold gravity research has revealed that gold particle shape transformation is one of the main factors explaining the lower recoveries of the plant units. Efforts to devise possible remedies for improving plant gravity recovery will be discussed.

Jan 1, 2013

By R. P. Townsend

It is a widely accepted "fact" that a Koepe friction hoist is generally the best solution for production hoisting when compared to a double drum hoists. This would appear to be true if one looks at the initial capital cost of just the hoist, and also if one compares the size of the motors selected for the duty. But is this the whole story? What are the longer term costs involved in the hoist&apos;s operation, and what are the relative efficiency&apos;s of the two designs? Perhaps the Koepe hoist design enjoys a better reputation than it deserves.

Jan 1, 2011

By M. J. Gole, R. E. T. Hill, S. J. Barnes

"The Agnew (also known as the Perseverance) nickel deposit and its northern extension, the Rocky&apos;s Reward deposit, form one of the world&apos;s largest accumulations of nickel sulphides hosted by komatiites. Agnew was previously classified as an ""intrusive dunite-associated"" deposit . It has now been shown that the sulphides are hosted by komatiite flows which underlie an adcumulate-textured dunite body that crystallized in a large lava channel.The rocks of the mine area have been subjected to a metamorphic temperature of550°C and pressure of up to 3 kb. The komatiites have mostly been reconstituted to olivine-amphibole chlorite assemblages. There is a zoned sequence of enstatite-, anthophylite-, talc- and antigorite-bearing assemblages inwards from the western margin of the ultramatic reflecting variations in the CO/HP ratio of metamorphic fluids.Facing directions are determined from variations in the proportions of metamorphic minerals and in rock compositions which reflect asymmetric layering in the flows . Olivine-sulphides matrix ore is hosted in a single 50 m thick, east-facing flow that is overlain by flows containing massive sulphides. Much of the massive sulphide has been physically remobilized into fold noses, faults and shear zones. Chemical diffusion of ore components has upgraded a sulphide-rich metasedimentary unit where it is in structural contact with massive ore.To the north, the mineralized flow sequence is separated from a stratigraphically higher komatiite sequence, the Perseverance ultramafic complex, by approximately 150 m of felsic meta volcanic and meta sedimentary rocks. Southward, the Perseverance ultramafic grades laterally into an olivine adcumulate body and its lower contact cuts progressively down stratigraphy until it lies directly on top of olivine-sulphide ore of the mineralized flow sequence. This discordant contact is interpreted as the base of a thermal erosion channel formed by a voluminous komatiite lava flow. This contact greatly influenced later deformation of the mineralized flow sequence."

Jan 1, 1989

By H. R. McCabe

"The study of a detailed series of structure and isopach maps of the Palaeozoic strata of southwestern Manitoba indicates that the principal Palaeozoic tectonic elements -the Williston Basin and Elk Point Basin -have been modified to a considerable extent by major tectonic features of the Precambrian basement. The principal basement feature is the break between the Churchill and Superior provinces, which coincides roughly with the Manitoba-Saskatchewan border. East-west-trending orogenic belts within the Superior crustal block may also be reflected to some extent in later Palaeozoic movements. In addition, the Superior crustal block, as a whole, appears to have had a slightly different response to the tectonic forces, giving rise to both basin subsidence and basin uplift. During periods of deposition, especially during Ordovician time, the Manitoba portion of the basin appears to have undergone a relatively higher rate of subsidence, whereas during periods of erosion relatively greater amounts of uplift and truncation have occurred. As a result, the depositional and erosional patterns for most of the Palaeozoic formations in southwestern Manitoba are somewhat anomalous relative to the regional basin framework.Some prominent Palaeozoic structures probably are the result of salt solution and differential compaction caused directly or indirectly by relatively minor tectonic movements related to Precambrian basement features. In particular, the prominent hinge line at the edge of the Devonian Prairie Evaporite salt basin may be due, in large part, to salt solution. Numerous other small structural lows, structural highs and isopach thicks, probably resulting from salt solution, occur along the salt edge and have been important in modifying and controlling Mississippian oil accumulation in the Daly-Virden producing area."

Jan 1, 1967

By Robert Macdonald, William Coombe, John F. Lewry

Gold occurrences have been known in the La Ronge Domain for many year . Mineable reserves have more recently been outlined and there is every prospect of a major gold camp being established in the domain within this decade. The La Ronge Domain lies in the Lower Proterozoic 'Trans-Hudson Orogen' and is part of a collage of Early Proterozoic crust comprising volcanoplutonic arcs, batholiths, associated volcaniclastics and volcanogenic sediments lying between the Superior Craton to the outheast and the reworked Archean basement/Aphebian cover terrain to the northwest. The domain has several lithostructural subdivisions, the most important of whjch , from a gold exploration point of view, is the Central Metavolcanic Belt. This belt is composed dominantly of a range of metavolcanic rocks and gabbroic to granitic intrusives, which geochemically resemble younger subduction-generated 'primitive' arcs developed on oceanic crust. U-Pb zircon geochronology indicates that the arc volcarusm and pre- to late-kjnematic plutonism occurred about 1890 Ma to 1850 Ma ago. The belt has an attained grade of upper greenschist to amphibolite facies and is relatively undeformed , though high strain zones occur locally. Most gold occurrences in the La Ronge Domain have been found in the Star-Waddy Lakes area of the Central Metavolcanic Belt, and in the Sulprude-MacKay Lakes area to the south which is interpreted as a tectonically dismembered part of the main belt. Both tratiformand vein-type gold occurrences are present in the domain; vein-type predominate and form nearly 90 per cent of the occurrences. The stratiform-type occurrences show a regional lithological a sociation with iron-rich sediments within proximal felsic volcanjc sequences. Some vein-type occurrences appear related to brittle fracturing associated with intrusive emplacement (the magmatic-hydrothermal "syn:' and "subvolcanic" veins) and faulting. However, most of the vein-type occurrences exhibit a spatial association with regionalscale ductile shear and other high strain zones, and were probably formed by metamorphichydrothermal processes.

Jan 1, 1986

By D. Verhulst

The Altair process digests ilmenite concentrate in high-chloride HC1 solution, with complete dissolution of titanium and iron. The Fe(III) ions are reduced to the ferrous form, and the solution is cooled to produce crystalline ferrous chloride. Titanium is transferred by solvent extraction into a purified, concentrated Ti stream, which is spray-hydrolyzed to produce TiO2 hydrate. The hydrate is further calcined with additives to generate a high-quality pigment. All the chloride streams are recycled. In the original flowsheet, the iron chloride is pyrohydrolyzed by spray roasting to regenerate 18% HCl, which is subsequently converted to HC1 gas and water by pressure-swing distillation. A modified flowsheet includes an alternative to iron chloride spray roasting, producing more concentrated HCl and decreasing the amount of solution to be distilled. Improvements in digestion, solvent extraction and final pigment production are also introduced. A 100 t/y pilot plant is being built and will test the new concepts and confirm the overall water, acid and impurity balances of the process.

Jan 1, 2006

By P. M. May, V. Gella

The deportment and speciation of trace elements during mining and minerals processing is becoming an area of increasing concern with regards to potential health and environment risks. The use of chemical modelling can enhance our basic understanding of the deportment and speciation of trace metals under conditions present in gold processing solutions, and assist in laboratory and field investigations. In this paper, we report the results of chemical speciation modelling using the JESS software package for the trace toxic elements Pb, Cd, Hg, Se and Te in cyanidation solutions of varying salinity and relate the models to experimental data. The speciation of mercury is examined in detail.

Jan 1, 2011

By H. Wotruba, L. von Ketelhodt, M. Kowalzcyk, M. Robben

ABSTRACT Decreasing reserves, water shortages, increasing energy costs, and environmental and social constraints are challenges to the gold mining industry that must be met with innovative machines and methods. This paper introduces the principles of sensor-based sorting and installations that demonstrate the technical and financial viability of the method. The scenarios discussed highlight the potential and advantages of this dry processing technology that requires little infrastructure. Case studies are presented for different ore types using optical- and X-ray transmission–based sorting. Current research is discussed in terms of the potential of near-infrared spectroscopy and X-ray fluorescence sorting for gold applications.

Jan 1, 2013

By G. Morin, F. Chiesa, B. Duchesne

The Quality index is a useful tool allowing to assess the metallurgical quality of aluminium AlSiMg foundry alloys (A356/357). Its value is calculated from the ultimate tensile strength and elongation; it increases with the metallurgical quality of the casting, i.e. with finer dendrites, lower microporosity and inclusion count and lower iron content. This Quality index does not depend on the degree of temper applied during the heat treatment (aging time and temperature). After defining the Quality index, it will be explained how it can be predicted from the knowledge of the local solidification conditions obtained from modelling. The paper will then present four case studies of castings for which the prediction of the Quality index by modelling was made. These case studies from different authors will involve the three most common casting processes used for producing high integrity aluminium castings, namely: sand casting, permanent mould casting and investment casting (lost wax). In all cases, the accuracy of the prediction will be assessed by comparing the predicted Quality index distributions to the experimental values based on the published measured values of the local tensile properties.

Jan 1, 2006

By Steven Hart

In September 2009, Newmont began the commissioning of a 3 stage crushing and milling circuit at its Boddington Gold Operation in Western Australia. The Boddington ore has been recognized as one of the hardest and most abrasive ores treated to date and this played a pivotal role in the selection of crushing and HPGR technology for this operation as opposed to the more conventional SABC circuit. This paper will examine the scale up from laboratory to pilot plant and full scale operation of the crushing circuit. There have been many challenges to overcome in the first 18 months of operation; however, the HPGRs have in general met design expectations and performance is expected to improve further with ongoing design changes

Jan 1, 2012

By P. E. Cavanagh

Introduction A comprehensive study of the economics of processes for smelting iron ores has been made by the Ontario Research Foundation on behalf of the Ontario Research Commission. This survey has included investigations of all processes in commercial use, and proposed processes which are still in the experimental stage. The two main objects of this work were to discover (l) whether any known processes would be particularly suited to present and future Canadian conditions, and (2) whether any new process would be of assistance in solving the present scrap shortage in Canada. The future prospects of the Canadian iron smelting industry have changed radically in the past ten years. For nearly twenty years before 1939 no iron ore was mined in Canada. The ore used was imported, mainly from the United States and Newfoundland. The economics of iron blast-furnace smelting always force the location of blast furnaces near the source of coal for making high-grade metallurgical coke, and near the market for iron and steel, rather than near the iron ore. Blast-furnace installations in Canada are confined to the north shores of the Great Lakes with ready access to United States coal and ore and the major Canadian markets, and to Nova Scotia near the coalfields of that Province. This distribution of primary smelting capacity naturally results in relatively high prices for iron and steel in the West, the North, and in Quebec.

Jan 1, 1948

By G. J. Kipouros, W. Judge

"The prevalent metal extraction processes for most reactive metals are fused salt electrolysis and metallothermic reduction. The feed material for both of these processes is the anhydrous chloride of the metal under consideration. Dehydration of the feed material is then a critical step in the production of most reactive metals and requires rigorous thermodynamic analysis. Thermodynamic data for most of the reactive metal chloride hydrates have not been measured. Improper dehydration of the metal chloride may lead to a prohibitive amount of hydroxychloride, oxychloride, and oxide. To prevent hydrolysis a certain pressure of hydrogen chloride is required. An estimation and prediction model is presented for the vapour pressures of reactive metal chloride hydrates in an attempt to deduce the conditions necessary for dehydration to proceed without hydrolysis. Thermodynamic data including heat capacities, standard entropies, and standard enthalpies are estimated/predicted for all conceivable intermediate hydrate compounds. Estimations are based on published data as well as trends proven in similar systems. The thermodynamic estimations and predictions are presented for the magnesium, neodymium, praseodymium, and dysprosium chloride hydrates. INTRODUCTIONThe high reactivity of metals such as the alkalis, alkaline earths, and lanthanides prevents their reduction by traditional pyro- or hydrometallurgy. In their elemental form, these metals are raw materials in the manufacture of intermediate products such as alloys and electronic components. Currently the only two viable metal production methods are fused salt electrolysis and metallothermic reduction. Various feed materials have been proposed for these processes. Using the chloride of the metal as a feed material offers advantages in separation and purity of the final product, as well as lower energy input. Chlorides, however, are hygroscopic and must be dehydrated before use. Improper dehydration will lead to a prohibitive amount of oxychloride which will lower efficiencies and contaminate the final product.Optimum conditions for proper dehydration of MgCl2•6H2O to produce pure MgCl2 without hydrolysis have been calculated from existent thermodynamic data and have been reported previously (Kipouros, 1987; 2001). Calculations were also performed for the case of production of pure anhydrous NdCl3 from NdCl3•6H2O (Roy, 1997)] and the mechanism of dehydration was elucidated. Some thermodynamic studies on the dehydration of chlorides of the rare earths have also been conducted (Sundstrom, 1997; Hong, 1997; Aschcroft, 1968; Haeseler, 1965; Ukraintseya, 1989)."

Jan 1, 2012