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By P. Zhang, K. Liu, L. Ou

"The strength and mechanism of Portland cement prepared from stone coal vanadium slag were studied in this paper. Initially, the slag was used as silicon raw materials to prepare clinker. By blending the prepared clinker with gypsum, waste, and fly ash, a series of different grades cement got well prepared. All of performances of the cement were up to the requirements of China’s national standard. The hydration products and microstructure of cement were identified and analyzed by X-ray diffraction and scanning electron microscopy. With the comparison of cement hydration characteristics at different ages, the strength formation mechanism of cement was clarified. The experimental results suggested that adding the fine materials (mainly waste and fly ash) to replace part of clinker would accelerate cement hydration, as it provided additional surfaces for the nucleation and growth of hydration products. And the hydration products were similar to ordinary Portland cement, mainly containing the amorphous calcium silicate hydrates (C-S-H), acicular ettringite (AFt) and portlandite (CH). With hydration time increasing, the hydration products continuously covered the cement particles, resulting in a thicker surface layer. As a result, it gradually condensed into a dense structure block with small pores and smooth surfaces, which led to higher strength. In conclusion, using the vanadium slag to prepare Portland cement can realize the utilization of solid mineral wastes, which will bring huge ecological and economic benefits.INTRODUCTIONWith the development of China’s mining industry, more and more mineral waste residue is discharged every year. These solid wastes cause varieties of resources and environmental problems on people’s living area. While at the same time, the demands of cement are increasing with the remarkable development of the construction industry. Thus, in recent years, utilization of proper solid waste to prepare cement has become an efficient way to deal with the solid mineral wastes problems (Boncukcuoglu, Kocakeri?M, & Tosunoglu, 2002; Simatupang, Hanafi, Purwasasmita, Imran, & Pane, 2012; Tsakiridis, Papadimitriou, Tsivilis, & Koroneos, 2008; Yun, Yong, Choi, Lee, & Lachemi, 2009)."

Jan 1, 2016

By S. Usui, Y. Shinohara, C. Tokoro, K. Horiuchi, S. Owada

Process optimization of heating and physical separation for Cobalt (Co) recycling from spent lithium ion battery (LIB) was investigated. LiCoO2 in spent LIB was transformed to LixCoO2 which was more easily decomposed than LiCoO2 by heating. Coexisting materials of aluminum and carbon, and sealed atmosphere of the LIB promoted LixCoO2 decomposition. In an atmosphere of Argon, 95 % of LixCoO2 in the spent LIB was decomposed to 76 % of Co oxide and 19 % of Co metal in 10 min at 823 K; a lower temperature than the theoretical value for LiCoO2. The Co oxide and Co metal exhibited magnetic properties and could be recovered by wet magnetic separation. Furthermore, slow heating was effective for grain growth of Co oxide and Co metal. At 2 K/min rate of heating, average grain size of Co oxide and Co metal were 239 µm and 28 µm respectively, whereas at 30 K/min they were 190 µm and 15 µm respectively. Therefore, separation efficiency for Co recovery by wet magnetic separation was increased when spent LIB was slowly heated at 2 K/min.

Jan 1, 2015

Operating CIP/CIL gold recovery plants in the arid regions of Western Australia face unique challenges due to water and ore quality issues. The presence of cations of Mg, Fe and Cu metals in water supplies and leached sulphide ores can have considerable effect on plant consumption of lime and cyanide, due to pH buffering and complexation effects. Reagent costs are critical to many of these operations. In this paper, computational modelling is used to analyse a number of process options to mitigate such issues. This requires careful consideration of the chemistry of the process system, and the ability to predict accurately the response of speciation and precipitation reactions to changing process conditions. The Mg-Fe-Cu-CN-H20 system is specifically modelled in this application. The Gibbs Free Energy Minimisation thermodynamic framework has been selected to model equilibrium phenomena. Furthermore, this approach has been extended to the process flowsheet level, incorporating multiple unit operations and recycle streams in a steady-state mass balance model. The Gibbs equilibrium composition module of HSC Chemistry software has been successfully integrated into the commercial flowsheeting package SysCAD. Consideration of the Gibbs Energy Minimisation capabilities of other flowsheeting packages has also been given. This approach has been successful in simulating the aqueous process chemistry typical of such plants. It has resulted in a predictive capability where equilibrium states respond appropriately to process changes. Potential cost savings may be identified by examining alternative process conditions to minimise overall reagent consumption.This methodology may be extended to other hydrometallurgical plants where issues of solution ideality, temperature and other equilibrium processes are sufficiently understood.

Jan 1, 2005

By Ernest A. Hodgson

A SERIOUS hazard which must be faced in some mines, though quite absent in others, is that of rockbursts. Bursts cannot be wholly avoided in such mines, but the hazard would largely disappear if they could be predicted. The problem of prediction resolves itself into that of measuring pressure in the mine and determining when that pressure nears a critical value. The geophysical approach to the problem lies in discovering some physical property of the rock, which varies with pressure, which can be measured for rock in place, and for which the indication of critical conditions is sufficiently definite and open scale. A physical property, suggested first in connection with earthquake pre-diction, is that of sub-audible snapping. It was argued that, as the pressure grows, the rock probably yields microscopically and that minute snapping occurs which is so faint as to be inaudible to the unaided ear. Experience has proved this to be the case. Following other earlier work begun early in 1939, experiments with this method were initiated at Lake Shore Mines in 1941, and equipment was slowly being developed in practice when, fortunately, it was found possible to by-pass this tedious development programme. Experiments with sub-audible snapping in mine rocks had been carried out by Dr. L. A. Obert of the U.S. Bureau of Mines and his associates over a period of about four years. An amplifier and a recorder were developed, each reasonably satisfactory in practice. Lake Shore Mines offers a tempting field for rockburst research. Dr. Obert was invited to test his equipment in this and other mines in Ontario and did so. As a result, he and the administrative personnel of the Bureau became interested in the Lake Shore experiments co the extent of most generously arranging for the manufacture of sets of their own designed equipment for use in this programme. The first three sets of recorders were ordered at once and were delivered in May, 1942. A second group of three sets, incorporating various improvements indicated by experience both in the United States and in Canada, reached Kirkland Lake in April, 1943. The pick-up devices, known as geophones, were made in the electronics laboratory at Lake Shore by Mr. Zack Gibbs, who has had charge of all the instrument development in this re-search.

Jan 1, 1943

By Ralph L. Rutherford

Introduction During the past twenty-five years we have seen considerable exploration for oil on the plains of southern and east-central Alberta. This exploration has to some extent gone on in cycles, with periodic starts, stops, and occasionally some reversals. Each major attempt is usually supplemented by the application of some new method of exploration and, following each period of exploration, drilling tests are made. Whereas oil-bearing horizons are the ultimate objective of these explorations, the preliminary investigation frequently aims at a discovery of structure based on the long accepted belief that accumulations of oil and gas are to a marked degree structurally controlled. At the inception of this general exploration for oil, it was natural that attention should be directed to areas where there was surface evidence of deformation of the underlying strata, but, as the programme progressed, it was found that these surface manifestations of structure were often deceptive when attempts were made to project them to depth, to involve the deeper strata. Drilling of test wells was the only satisfactory method of obtaining exact information.

Jan 1, 1946

By J. G. Pearson, F. H. MacDougall, A. G. Galley

The difference in age, host rock lithology, alteration and style of mineralization indicates a fundamental difference in the format ion of gold deposits in the Flin Flon and Amisk Lake areas. The Flin Flon area contains early quartz-sulfide-gold veins fo rmed within intermittently active fractures and later plutonic hosted deposits thought to be generated in a porphyry system. In the Amisk Lake area two types of gold occurrences are recognized: I) gold-quartzcarbonate- sulfide veins within or flanking fault zones and 2) structurally and stratigraphical ly controlled zones of dissem inated and vein type sulfide-gold mineralization within extrusive and intrusive rhyolite and dacite porphyries. Both types of deposits are set within supracrustal rocks. are accompanied by intense alteration haloes and were formed prior to the major deformation event suggesting an early, epigenetic hydrothermal origin.

Jan 1, 1986

By J. B. Yianatos, F. A. Contreras

Mineral carrying rates across the pulp-froth interface in the range of 1.4-3.2 tph/m2 and bubble surface coverages between 7 and 22 %, have been determined in large rougher flotation cells operated under normal conditions. To evaluate these variables, measurements of bubble size distribution, bubble load and size distribution of particles collected by true flotation, were performed at different concentrators. A model for estimating the bubble surface coverage at the pulp-froth interface level as a function of bubble load, Sauter mean bubble diameter and particle size distribution of the mineral collected by true flotation, was developed. Bubble loadings in the range 24-70 kg/m3, bubble sizes between 1.5 and 3.2 mm and superficial gas rates between 1.2 and 2.0 emfs, were measured in copper rougher flotation cells under normal operating conditions. Estimated bubble surface area fluxes were in the range 31 to 62 cm2/s/cm2- Results of carrying rates and bubble surface coverage, at the pulp-froth interface, were significantly lower than the maximum carrying rate for the collection zone, indicating that in this case is difficult to achieve maximum carrying rate at the pulp-froth interface level. The main constraints regarding carrying capacity limitations are then related to the froth transport characteristics (i.e. cell design, froth residence time, froth stability, froth recovery). Advances in Mineral Processing Science and Technology Proceedings of the 48th Annual Conference of Metallurgists ofCIM Sudbury, Ontario, Canada Edited by

Jan 1, 2009

By T. Abu Leil

A new class of ternary Mg-Sn-Ca alloys is being developed to address the dual demands of corrosion and creep resistance at service temperatures. While tin has proven to enhance the corrosion resistance, calcium is expected to significantly increase their creep resistance of binary magnesium alloys. Their effects in ternary magnesium alloys are not yet known. The series of alloys studied has Sn and Ca in the ranges 3-6% and 1¬2%, respectively. The results indicate that these alloys have two-phase structures with CaMgSn phase dispersed in a matrix that is predominantly a solid solution of magnesium. The corrosion behavior of these alloys has been investigated by means of salt spray tests and potentio-dynamic measurements. Creep behavior of these alloys was measured at a temperature of 135 C under an applied compressive stress of 85 MPa. Scanning Electron Microscopy with Energy Dispersive X-ray facility and X-ray Diffraction techniques were used to characterize the microstructures. The results indicate the prospect of designing alloys that can provide optimum combinations of corrosion and creep resistance by adjusting the relative compositions of Sn and Ca in the system.

Jan 1, 2006

By Marcel Vallee, D. C. Gagnon, C. CARBONNEAU, P. ST-JULIEN

The Magdalen Islands archipelago, a cluster of fifteen islands, is located near the centre of the Gulf of St. Lawrence on the thickest portion of the Carboniferous Fundy Basin of the Maritime Pro vinces. The bedrock of the Magdalen Platform includes a thick succession of evaporites of Visean Age, occurring as a series of thickenings, ridges, domes and diapirs reaching a probable vertical thickness of close to 6000 m. The emplacement of 1hese salt structures by flowage has much dislurbed 1he SlrOligraphic sequence of the rocks of the Windsor Group, particularly 1he Havre-aux-Maisons Formation. Subsequent tectonic movemenl has broken the overlying Cap-auxMeules Forma1ion info an assemblage of panels and blocks now slightly tilted. Following detailed gravimetric surveys and more than 30,000 m of diamond drilling, SOQUEM has discovered, at various dep1hs, seven salt domes on four of 1he main islands of the archipelago. These evaporite bodies generally are localized near the cemre of complex anticlinal struclUres where diapiric movements and faulting have disturbed the original stratigraphic succession. At Rocher du Dauphin near Grosse 1/e, in 1he northern part of the archipelago, Seleine a SOQUEM subsidiary is developing a mining complex with an annual capaci1y of 1,250,000 1onnes of deicing salt for 1he Canadian and Eas1ern United Swtes marke1s. The stan of operations is scheduled for April 1982.

Jan 1, 1984

By K. L. Ford, D. R. Lentz, J. H. Rickard, R. P. Taylor

Abstract - Coupled gamma-ray spectrometric and lithogeochemical studies throughout the Heath Steele Mines area, Bathurst Camp, New Brunswick, indicate that primary and secondary geochemical differences exist between the stratigraphic footwall and hangingwall crystal tuff units which host the massive sulfide deposits. Of particular interest is Th, and to a lesser extent, Zr and Y, which are more concentrated in the hangingwall than the footwall crystal tuffs, whereas the opposite is true for TiO2. This expands on earlier lithogeochemical-chemostratigraphic results concentrated in the eastern part of the Heath Steele belt that led to revision of the local stratigraphy, and necessitated a structural re-interpretation of the area with implications for exploration. Although K depletion (decreased K and K/Th) is typical of chloritized footwall zones of chloritization, these features were not fully apparent here due to the recessive nature of these altered zones. In situ radiometric analysis using a portable gamma-ray spectrometer is a rapid, inexpensive analytical technique for chemostratigraphic characterization of rock units within volcanogenic massive sulfide deposit settings, provided there is a contrast in the distribution of natural radioelements, particularly Th and K.

Jan 1, 1998

By R. Frank Chiappetta, E. B. Wilson

"The maintenance records for AL-60 airlegs at Falconbridge Ltd. are used to demonstrate some of the procedures for the analysis of such data.The data are not representative of pure failure s of one type or another. In fact, the records are for the undefined pseudo-failures which are usually found in industrial operations. However, because the machines are brought to the shop only when inoperative, the individual recorded components are treated as failures. Manual calculations are conducted to show the analysis of variance (ANO VA) approach to determine whether certain data can be combined; only a limited number of the 206 machines being considered. The manual procedures continue with the weighting of the suspensions; i.e. terminations f or reasons other than the failure of the given component. After the data are sequenced in the proper order, the nature or pattern of the data is determined using the Kolmogorov-Smirnov (KS) test.It is recognized that these manual examples must be replaced by compute r methods 10 process voluminous data of this nature. Such programs are developed and available. However, a program called RELCODE is used in this case to correspond to the manual examples and to take into account the suspensions. These analytical procedures form the basis for those studies required for good maintenance management."

Jan 1, 1985

By Antonio Segatori, Bjørn Holmedal, Kai Zhang, Trond Aukrust, Knut Marthinsen

"The visual appearance and mechanical properties of aluminium alloy extrusions are strongly dependent on the microstructure and texture of the extruded profiles, where the desired microstructure and texture may depend on the specific applications. In the present work, the evolution of deformation, as well as recrystallization textures during extrusion of AA6xxx aluminium alloys, have been experimentally and numerically investigated. Extrusion trials were performed in a laboratory extrusion set-up, which enabled immediate water-quenching of the profiles at the exit of the die, and thus the possibility to capture the deformation texture prior to post-extrusion recrystallization. The textures and their through-thickness variations were experimentally measured by the electron back-scatter diffraction technique (EBSD, and the deformation textures numerically modelled by coupling FEM flow simulations and crystal plasticity (CP) simulations. Different CP models as well as different choices of model parameters were employed and evaluated for texture predictions. With an appropriate choice of crystal plasticity model and model parameters, the deformation texture can mainly be predicted, although the accurate intensities are hard to reproduce. The corresponding recrystallization textures, either generated through spontaneous recrystallization of the extruded profiles or through post-extrusion annealing, are far more challenging to reproduce with available recrystallization models.INTRODUCTION Extrusion is a widely applied thermal-mechanical process to produce aluminium profiles. The properties of the profiles, for example mechanical, fatigue, fracture, corrosion as well surface appearance, are strongly dependent on the underlying microstructure and texture, and the requirements with respect to these aspects may vary with applications (Ralston et al., 2010; Dumoulin et al., 2012; Donati et al., 2013). Moreover, it is often a challenge to produce extrusions with a consistent and homogenous grain structure and texture along as well as through the cross section of the profiles. It is thus vital to understand and be able to predict (model) how different microstructures and textures are formed and how they evolve during and after extrusion, as basis for controlling the final appearance and properties of extruded profiles."

Jan 1, 2018

By D. Bois, P. Keating, J. Lemieux, M. A. Vallée, M. Allard, R. S. Smith, L. Z. Cheng, M. Chouteau, D. K. Fountain

"Abstract - MEGATEMII airborne electromagnetic data collected over the Iso and New Insco massive sulfide deposits have been modeled using three modeling packages. The EMQ package is a quick inversion tool which indicates that the Iso body is a dipping, plate-like body. The New Insco body is inferred to have a geometry somewhere between a dipping plate and a sphere. The Maxwell package was used to refine the properties of the plate-like body at Iso. The EMIGMA package was able to identify which parts of the New Insco orebody were more conductive. It was observed that the most conductive parts correspond to copper-rich zones and the next most conductive to pyrite-rich zones. The EMIGMA package was also used to show that a thick-prism model might be more appropriate for the New Insco orebody. Gravity modeling constrained by the known geology was successful in identifying the denser sulfide zones. The densest zones appear to be pyrite rich. Magnetic modeling identified diabase dikes. Over New Insco, a small magnetic anomaly was attributed to pyrrhotite-rich sulfides. There was only a weak magnetic anomaly over the Iso body, consistent with the nonmagnetic sulfides logged in the holes drilled at that location. Sommaire - Les données MEGATEMII recueillies au-dessus des dépôts d’Iso et de New Insco ont été interprétées en utilisant trois outils de modélisation différents. L’outil EMQ a été utilisé comme un outil d’inversion rapide suggérant que le dépôt Iso peut être considéré comme une plaque inclinée, et que le dépôt de New Insco se situe quelque part entre une plaque et une sphère. L’outil Maxwell a été utilisé pour raffiner les propriétés du dépôt Iso. L’outil EMIGMA nous a permis d’identifier les différences de conductivité à l’intérieur du dépôt Iso. Il a été observé que la partie la plus conductrice correspond à la zone riche en cuivre, suivie par la zone riche en pyrite. L’outil EMIGMA a aussi permis de montrer qu’un modèle de prisme épais pourrait être plus approprié pour décrire le dépôt New Insco. La modélisation des données gravimétriques, contrainte par la géologie connue, définit bien la zone de sulfures massifs. La zone de pyrite semble être la plus dense. La modélisation des données magnétiques identifie bien les dykes de diabase. Au-dessus du dépôt New Insco, on observe une faible anomalie magnétique correspondant aux sulfures non magnétiques observés dans les carottes de forages à cet endroit."

Jan 1, 2006

By C. Carrasco

Caletones Smelter, Division El Teniente of Codelco Chile, has used Teniente Converter (TC) as the only smelting unit since November 2000. The modernization project considered the shutdown of the last reverberatory furnace, the installation of the fourth Teniente Slag Cleaning Furnace, the installation of a new fluidized bed dryer and the modification of the concentrate injection system into TC. The modernization project and related investments allowed for the increase of the smelting capacity up to 1.25 million t of concentrate annually.Next stage of the smelter expansion in the year 2004 considered the increase of the smelting capacity up to 1.44 million t/year. The expansion required technology modernization and the installation of the new equipment, such as concentrate injection system, oxygen plant, fluidized bed dryer and storage bin. Currently the annual smelting capacity is about 1.35 million t of copper concentrate, being limited by sulphuric acid plant treatment capacity. This paper presents the technology and production evolution in the Caletones Smelter in the years 2000 - 2006, demonstrating the potential of development and competitiveness of Teniente Converter as world-wide recognized smelting/converting reactor.

Jan 1, 2007

By M. M. Williams

ALBERTA has been generously endowed with oil, natural gas, coal and water power, thus giving power producers a wide choice in the type of plant and fuel which can be used. Therefore, with such a variety of energy sources to choose from, why was coal selected as the primary fuel at Calgary Power's Wabamun steam plant? This part of the paper will cover the circumstances that led the Company to decide in favour of coal. The second part, to be presented by C. F. Doerr, will describe how the Wabamun coal mine has been developed to supply the large fuel requirements of the power plant. Before considering the Wabamun plant, we require a general under-standing of? the Company's electric system and load. Power is fed into a 5,100-mile high-voltage transmission grid from eleven hydroelectric plants and from the Wabamun steam electric plant. These plants have a combined generating capacity of 820,000 horse-power. Of this total, the hydro

Jan 1, 1963

By J. P. Harrison, R. Roostaei

"In this paper we investigate the consequences of using conventional triaxial peak strength criteria in the polyaxial stress conditions that occur around the end of a long circular underground opening. A series of 3d boundary element analyses were performed using Examine3D to determine the stresses induced around the tunnel in different in-situ stress conditions. To discuss the applicability of a triaxial strength criterion in failure prediction, strength factors were computed for both the Ottosen polyaxial strength criterion and the triaxial Hoek-Brown criterion. Assuming that the Ottosen criterion is an accurate indicator of strength factor, the discrepancy from this value due to the Hoek-Brown criterion is the error in prediction.In order to simultaneously show the error in prediction and actual strength factor, a quantitative bivariate colour scheme is used to visualize the results. This allows rapid identification of regions with large error, and where either unsafe or overly conservative conditions occur. We show how the inappropriate use of triaxial criteria rather than polyaxial criteria leads to an under- or over-estimation of strength factor, and can result in uneconomic or unsafe design. Extending the analysis to different in situ stress regimes shows how the in situ stress conditions affect the assessment."

Jan 1, 2015

By M MacMillan

THE following is a brief description of the method of hoisting ore automatically at the No. 14 shaft of Mcintyre Porcupine Mines, Limited, Schumacher, Ontario. All ore and waste below the 3875-ft. level is hoisted up No. 14 shaft from the 7000-ft. level to the 3000-ft. level. Seventy to seventy-five per cent of the mining is done in this area. The shaft consists of four compartments: a man way, a ventilation compartment and two skip compartments. The hoist, located on the 3500-ft. level (see Figure l), is an 80-in.-diameter, 4-rope friction winder, utilizing two 6-ton front-dump skips in balance. The hoist is powered by a 1,100-h.p. A.C. motor, the maxi-mum speed being 2,400 ft. per minute. The operation can be either manual, push-button automatic from the pocket, or fully automatic. Men can be raised or lowered in the skips, using a collapsible aluminum platform placed inside the skip box.

Jan 1, 1963

By H. Kolcz, G. S. Dobby, R. Stratton-Crawley, S. W. Wilson

"The Matte Separation plant at Inco's Copper Cliff Smelter Complex is described. The continuing implementation of flotation column technology in the flowsheet in various applications is reviewed. Comparative studies on 0.038, 0.10, 1.1 and 1.8 m diameter columns have been carried out. It was demonstrated that consistent metallurgical performance was obtained with both pilot- and plant-scale units. Grade-recovery relationships for plant columns can be predicted with confidence from data obtained from test equipment. The work indicates further areas of the flowsheet in which columns present an attractive alternative to conventional cells. INCO’s MATTE SEPARATION PROCESSNickel concentrate from Inco’s Sudbury area mills has been processed in the Copper Cliff smelter for sixty years. Prior to that, Sudbury ores had been smelted directly. Historically, copper-nickel separation from smelter converter matte was achieved by the classical Orford process. In the mid-1940s Inco developed an improved separation scheme based on mineral processing methods, the Matte Separation Process. A generalized Copper Cliff Smelter Complex flowsheet is shown in Figure 1.Iron sulfide and gangue contained in the nickel concentrate are rejected in the smelting-converting process. The molten product, typically containing 50% Ni, 25% CU and 22% s, is cast at about 1000 ºC, into floor moulds and allowed to slowly cool for four days. During this period nickel sulfide (heazlewoodite, Ni,S,), copper sulfide (chalcocite, cu,S) and a copper-nickel metallic alloy precipitate and form a coarse grain structure that is amenable to separation by physical means. The phase chemistry of this system has been described previously by Sproule et al (1). This matte then becomes the feed to the Matte Separation Process.A simplified block flowsheet of the Matte Separation Process is shown in Figure 2. Matte ingots, typically weighing 20 tonnes each, are broken and crushed in a three stage crushing plant to approximately minus 0.01 m and conveyed to the Matte Separation building. Grinding is carried out in two parallel circuits each consisting of a rod and ball mill in series producing a flotation feed which is 65% minus 44 microns. Typical throughput of each grinding circuit is 650 tonnes/day. The metallic fraction of the feed is recovered by magnetic separation. This product, containing about 66% Ni and 15% CU, is a major component of the feed to the Copper Cliff Nickel Refinery."

Jan 1, 1990

This paper describes results of an investigation of fracture during tube expansion of 5052 and 5754 aluminum seam-welded tubes to optimize the forming of aluminum tubes during hydroforming. The tubes were produced in laboratory by press forming of tubular blanks and pilot-scale high frequency induction welding. The effect of property mismatch between the weld and base metal has been investigated. The material work-hardening was obtained by roll forming of sheet blanks in the 0-temper and H32 temper condition. The results showed that a significant work-hardening can be present in aluminum tube without causing weld fracture during tube expansion. The work-hardening increases the yield-strength mismatch between base metal and weld. Annealing reduces the hardness of base metal leading to more uniform deformation during tube expansion. As a result the occurrence of weld fracture is reduced. The study showed significant deformation of the welds during tube expansion. Weld thinning can be as large as parent-material thinning before fracture. To avoid fracture at the weld joint, good formability and high yield strength of the weld is needed. FEM simulation showed that minimizing the width of the weld joint can reduce thinning of the weld.

Jan 1, 2004

By J. M. Wetherill

"This paper presents the results of an investigation into the level of radon, as against the natural background, at the Vicary Creek coal mine in Alberta. The concentrations of radon and daughter products detected in the mine were considered to be insignificantly higher than the concentrations of naturally occurring radon and thus do not constitute a health hazard to the miners.INTRODUCTIONTHE HIGH INCIDENCE OF LUNG CANCER among miners exposed to radon was established some thirty years ago. The presence of this gas in mines is primarily associated with pitchblende extraction operations, al-though coal contains detectab`e quantities of U30s. A previous study bas shown that coal from southwestern Alberta (Exshaw and Banff) contains lower than average concentrations of this element (1).As part of a general investigation into the occupational health environment of coal miners in Alberta, field measurements were made to establish the level of radon and to investigate the natural background radiation in the Vicary Creek coal mine, located some 16 miles north of Coleman, Alberta, on the easternmost slopes of the Rocky Mountains."

Jan 1, 1968