Search Documents

By T. T. Wang, T. H. Huang, Y. C. Chiu

Quantitatively analyzing deformation of a tunnel with lining anomalies for structural safety evaluation is essential for sustainable tunnel engineering. However, a complete theory and associated methodology accounted for displacement of a built tunnel is absent. This manuscript introduces a novel characteristic matrix method proposed by the authors which is an integrated procedure that analyzes displacement of rock tunnels in operation. First, establish a numerical model expressing a specific state of the tunnel in interest. Derive the characteristic displacement modes by a unit disturbances and check their independency. Once the characteristic displacement modes are proved to be orthogonal (independent), they are ready for use. Given a tunnel displacement, modal decomposition returns the magnitude of each characteristic displacement modes that together consist the given displacement. By realizing the definite value of horizontal and vertical translation, rotation, uniform compression/expansion, elliptic deformation, triangular deformation…etc. for a tunnel displacement, one can distinguish tunnel displacement and deformation types from their modal composition. A circular tunnel with elastic structure and surrounded by elastic rock mass is chosen to demonstrate the outcome of characteristic modes and how they work. The influences of tunnel shape, elastic modulus ratio between rock mass and tunnel structure, and numbers of monitoring points on a tunnel profile were also discussed. Identifying possible tunnel deformation causes is attainable if further connections between mode combination and force increments were built.

Jan 1, 2015

By H. L. Snyder

This paper outlines the approach to the underground construction work involved in the Churchill Falls Power Project. It is the first in a series of papers which CIM Bulletin plans to publish as the different 11hases of this large-scale operation evolve.

Jan 1, 1968

By A. G. Eccles

Western Mines' milling circuit produces three concentrates (copper, lead and zinc), with the tailings being disposed of at the bottom of Buttle Lake. In view of the mine's location and the method of tailing disposal, a comprehensive pollution control program has been in effect since start-up. Changes -in the ore over the past few years have required the use of increasing quantities of sodium cyanide in order to effect a good copper-lead separation. This led to the use of alkaline chlorination for destruction of ?residual cyanide and precipitation of dissolved copper contained in the tailing effluent. The development of Western Mines' alkaline chlorination plant is discussed in detail, including initial test work and the evolution of procedures leading to the present operation. The current monitoring program is also reviewed.

Jan 1, 1977

By G. Hamel

The LCL&L process (Low Caustic Leaching & Liming) is a patented hydrometallurgical route developed by Rio Tinto Alcan (RTA) to economically process spent pot lining (SPL) generated by aluminum cells. The three resulting end-products (carbonaceous, fluorinated and caustic liquor) are inert and have valorization possibilities. An industrial size pilot plant located in Saguenay (Quebec) was inaugurated in mid-2008 to demonstrate and optimize the technology. This paper describes characteristics of the LCL&L process and the experience acquired by RTA since the plant's start-up, including ramp-up capacity and technology challenges that were overcome. Possible end-products valorization methods are also presented. The carbonaceous end-product can be separated into carbon and brick rich fractions and used as either alternative fuel, reducing agents, or as raw material for third party processes. The development of a conversion process for the fluorinated end-product would allow its reuse as a substitute to fluorspar mineral for aluminum fluoride production. Finally concentrated caustic liquor is already valorized at the nearby RTA Vaudreuil alumina refinery.

Jan 1, 2011

By A. Zorkovská, S. Castro, P. Baláž, Z. Bujnáková

Enargite (Cu3AsS4) belongs among refractory copper minerals with very low hydrometallurgical extractability of copper. An application of enargite leaching in acid solutions leads to simultaneous dissolution of copper and arsenic and the final leach solutions have to be treated for the separation of both elements. However, the alkaline leaching of enargite is selective. Arsenic passes into leach while produced copper sulphide represents the raw material suitable for pyrometallurgy. The hydrometallurgical processing of mineral can be influenced positively by mechanochemical route. We have shown that more than 80 % of arsenic can be extracted from enargite concentrate by atmospheric alkaline leaching at 95 °C when mechanical activation in an attritor is applied. The produced Cu2S can be further treated with elemental iron where mechanochemical intervention is applied in the second stage of enargite processing. The final product forms Cu/FeS nanocomposite from which copper nanoparticles can be easily separated. The illustrated concept of copper obtaining from copper sulphide is an example of so-called “dry” processing, as reactions in gas and liquid phases are excluded. This concept of environmentally friendly metallurgical processing can be classified as an impetus for novel technology to produce copper from enargite concentrates.

Jan 1, 2012

By J. H. Schloen

"One of the most important phases in Canada's relatively rapid development of its metal mining and refining industries was launched in 1928 when the directors of Noranda Mines Limited decided to establish an electrolytic copper refinery ""somewhere in Eastern Canada”. Noranda's president, J.Y. Murdoch, had already evolved the company's ""mine to market"" policy and was determined to prove the economic feasibility of refining Noranda copper in Canada. The time appeared to be ripe as buoyant business conditions continued into 1929. In addition, proven ore reserves at the Horne Mine in northwest Quebec had virtually tripled and the price of copper had reached a healthy 15 cents per pound. Letters Patent incorporating the company bearing the date February 6, 1929 had been granted by the Secretary of State in accordance with an application that specified a capital structure of $2 million divided into 20 000 shares with a value of $100 each. Noranda assumed 70% of the original investment in the proposed refinery, while the Nicholas Copper Company of New York (which later became Phelps Dodge Corporation) and British Metal Corporation Ltd. of London, England, each were responsible for 15%. Nicholas Copper Company agreed to supply the design and to supervise the construction of the refinery and British Metal Corporation would act as sales agent and market the refinery's products."

Jan 1, 1999

A direct comparison has been undertaken between laboratory wind tunnel experimentation and computational fluid dynamics simulation of a 3D manufactured analogue for a body of fractured broken rock, created with CAD/CAM techniques. Detailed descriptions of the ?design? of the analogue (using a discrete element analysis multi-body simulator), its manufacture (using computer aided design and 3D printing technology) and the laboratory experimentation (inserting the physical analogue into a laboratory scale wind tunnel) are presented. The agreement of the results of direct experimental observations on the manufactured analogue with the values from CFD simulations of those experiments justifies the utilization of a CFD environment for the practical investigation of geometric factors controlling air flow and heat exchange in complex assemblages of broken rock blocks. The ultimate goal is described, that of developing functional relations between bulk properties of such assemblages (such as their porosity and bulk density) and the low-level geometric factors that dictate the air flow behaviour, such as the equivalent perimeter length of the cross-sectional area available for flow, or average flow path tortuosity. A practical application area of the work in the mining context is also described; equivalent continuum air flow and heat transfer constitutive models developed on the CFD tool from such functional relations are useful in characterization of seasonal heat storage in large scale bodies (approximately 1 km3) of broken rock.

Aug 1, 2013

By D. M. Baird

"THE Island of Newfoundland lies on the extreme eastern edge of the continent of North America and at the extreme northeastern end of the Appalachian geological province. Its belonging to the Appalachian province is shown in the geological history of the region and in the rock types and structures.Geosynclinal sedimentation in early and middle Palaeozoic times was interrupted by Taconic and, more profoundly, by Acadian, mountain building activity. Mid-Palaeo-zoic intrusions range from masses of serpentinized ultrabasic rocks to granite batholiths. A Carboniferous overlay of continental and shallow, drying sea types covers the earlier developed complex. Local basins in these times were filled with products of the erosion of tl1e earlier rocks, and, locally, grew the right kind of vegetation to make thin, discontinuons seams and pockets of coal. Post-early Pennsylvanian history is one of erosion and pene-planation with renewal of movement along many of the older fault systems."

Jan 1, 1960

By Rhual L. Guerguerian

MINING has been practised by mankind for over sixty centuries (1). In 1876, the "ball mill" was patented, and during the century that followed rotary grinding developed to the state where individual machines are treating tens of thousands of tons of ore per day. This paper gives a brief description of design practices prior to the availability of advanced facilities, followed by modern analytical design development at Dominion over the past ten years.

Jan 1, 1978

By H. J. White

Haynes International, a world leader in the manufacture and production of nickel, and cobalt base alloys has invented and developed a low cost high temperature material, with a unique combination of superior oxidation resistance and weldability/ fabricability. HAYNES® HR-224TM (Ni ? 27.5Fe ? 20Cr ?3.8A1 ? 0.3Si ? 0.3Ti) forms a planar/ continuous/ adherent aluminum oxide film at high temperatures which has been shown to effectively limit chromium poisoning in solid oxide fuel, cell, systems. A 20,000 pound vacuum induction melted (VIM) + electroslag remelted (ESR) heat has been melted and converted into various product forms: sheet, plate, bar, welded tubing, wire, etc. The alloy was designed for service in severely oxidizing environments recuperators, automotive catalytic converters, wire strand annealing furnace tubes, etc. and has been of great interest to solid oxide fuel, cell, manufacturers as a materials of construction in balance of plant (BOP) design. This manuscript presents the physical, properties, mechanica, properties, and oxidation resistance of the alloy compared to other materials being considered for solid oxide fuel, cell, design

Jan 1, 2010

By Vladislava A. Ignatkina, Fillip O. Milovich, Vladimir A. Bocharov

"Complex research of flotation concentrates of monomineral fractions of chalcopyrite, sphalerite, galena, pyrite, pyrrhotite included methods of adsorption of collectors, surface compounds by IR ATR, and surface films of flotoreagents by TEM. They revealed that the proportion of the parts of thionocarbamate (TC) and dithiophosphate had an effect on the adsorption rate of the components of minerals, on the presence of characteristic bands, and, what is an important, visualized surface film of organic flotation reagents on the particles of concentrates by TEM. The predominance of thionocarbamate in a composition selectively increases the adsorption rate constant of the components and recovery of chalcopyrite compared with sphalerite and galena. The highest flotation rate using TC is characteristic for chalcopyrite (0.62 min- 1) in case of individual use, and it's in combination with butyl xanthate (25% butyl xanthate or 3:1) 0.89 min-1 too. We studied the ternary blend - dithiophosphate: thionocarbamates: butyl xanthate. The increase of the proportion of butyl xanthate in combination reduces the contrast of the flotation rate among all sulfides.Practice flotation of refractory sulfide copper-zinc ores of the Urals (content sulfide iron - 75- 95%) confirmed that the use of a combination of selective collectors increases selective recovery of copper sulfide minerals up to 50% at the first fraction that is the conditioned copper concentrate. New selective sulfhydryl collectors resulted in high levels of recovery of copper into a concentrate - more than 90% - against 70-72% (butyl xanthate) from copper-pyrite ore. Low floatability of iron sulfides has been obtained by selective sulfhydryl collectors. Using weak selective sulfhydryl collectors can reduce pH into collective or selective flotation from pH 10-10.5 to pH = 7.2-7.5, which improves the quality of individual concentrates of nonferrous metals and their recovery. The same is true for polymetalic sulfide ore. The volume of gold recovery also increased."

Jan 1, 2016

By C. H. B. Leitch

"The Bralorne-Pioneer deposit produced more gold than any other deposit in British Columbia over its 70 years of operation (130 kg or 4 million oz of Au, from 7 million tonnes of 18 glt ore). Mineralization is related to a suite of late Cretaceous albitite dykes of 85 to 90 Ma age. It thus occurred long after and is genetically unrelated to the Early Permian (275 Ma) Bralorne diorite and soda granite.The major veins strike about 110 degrees and dip north at 70 degrees, with slickensides plunging 45 degrees east that indicate last movement was reverse. Major ore shoots in the veins occupy somewhat less than 20% of the vein and plunge steeply west, roughly perpendicular to the slickensides. The structures that contain the veins probably formed at around 95 to 90 Ma during a strike-slip episode with easterly directed maximum compression.Disseminated pyrite, pyrrhotite, and minor chalcopyrite occur within envelopes up to several metres from the veins. Arsenopyrite is confined to vein selvages. Local sphalerite and galena appear to correlate with gold-rich portions of the veins. Traces of tetrahedrite and stibnite have been observed but tellurides have not. Gold is found principally as thin smeared flakes of the native metal in the black sulphidic septae of the strongly ribboned veins. Hydrothermal alteration envelopes around the veins grade outwards from intensely foliated quartz - ankerite - sercite (±fuchsite) to less sheared calcite - chlorite - albite to unsheared epidote -calcite.Open-space vein filling textures found in the deep (mesothermal) environment at Bralorne can be explained by a fault- valve model. High-angle reverse faults may have acted as fluid-pressure activated valves on geopressured reservoirs, causing large cyclic fluctuations in fluid pressure that promoted mineral deposition in an episodic fashion . The faults that were mineralized were reactivated sub-vertical former strike slip faults, oriented at a high angle to the northeast-directed stress in a compressive regime."

Jan 1, 1990

By M. E. Holter

"Five main lignite seams occur in the Tertiary Ravenscrag Formation in the Eastevan area, at depths of 100 feet or less. They are named, in ascending order: the Boundary, Estevan, Souris, Roche Percee and Short Creek seams. A total sequence of approximately 250 feet is represented by the coal beds and interstratified clays, silts and sands. Strata dip to the southeast at 25 feet per mile or less and trike northeast. Large areas underlain by coal seams at shallow depths are delineated. Reserve calculations are dependent on detailed information on seam thicknesses and feasible stripmining depths. The stratigraphically higher seams are thinner on the average than lower seams and this, together with the increase in elastic size fractions in higher strata, suggests a retreat of a Tertiary marine margin to the south during the closing depositional history of coal seams and associated strata."

Jan 1, 1972

By W J. Riva

This paper reviews the circumstances that led to the development and construction of a commercial-scale vertical shaft carbonizer at Conmore, Alberta. This form coking process may be regarded as having potential application in other areas. Coal pelletizing offers a promising method of decreasing coal agglomeration costs under certain circumstances. Pellets can be rolled easily from -35-mesh coal, provided that a minimum of -200-mesh coal is present. Bentonite was found to be the best binder and was most effective when added in amounts of about 2 per cent. The water content of the coal pellets was observed to vary from 18 to 23 per cent. As a by-product of this investigation, it seems possible that fine coal could be converted into stoker feed by this process. A short investigation of the effect of heating rate on the carbonization of pellets was conducted. The low maximum heating rates in certain temperature ranges, necessary to avoid crack formation in the pellets as reported by other

Jan 1, 1964

By Robin Sheremeta

Fording Greenhills first acquired GPS (Global Positioning System) technology with the commissioning of a GPS-based dispatch system in December 1994. The second exposure to satellite technology came with the conversion of the conventional optical survey system to a high-resolution GPS system in June 1995. In September 1995,a GPS-based grade control system was tested on the largest shovel (Marion 301 — 58 cubic yard).In January 1996, the system was added to all of the cable shovels (2 P&H 2800s). All three applications of GPS at Greenhills are fully operational and producing positive results. This paper will focus on the practical application of GPS in a mining environment and the effect that GPS technology has had on the Greenhills Mine.

Jan 1, 1996

By Katsutoshi Saibara

Network communication note is a cloud system for an earthwork project. It enables backhoe operators and dump truck drivers to monitor their own works in progress currently and performed up to the present, and to have opportunity to reflect on their own bearings in the earthwork operations, and then could increase their situational awareness to the actual work conditions. First, this paper presents problems and purpose. Secondly, the configuration of the network communication note is reported. Thirdly, examples of communications enhanced by the network communication note are shown. Finally, remarks are described.

Aug 1, 2013

By B. K. Mishra, Avijit Biswal, B. C. Tripathy, Abhijeet Singh, K. Sanjay, T. Subbaiah

We studied theeffect of anode substrates such as pure lead (Pb), lead antimony (Pb-Sb), and lead-silver (Pb-Ag) on the structural and electrochemical properties of electrolytic manganese dioxide (EMD). X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and chemical analyses were used to determine the structural and chemical characteristics of the EMD samples. The charge-discharge profile was studied in 9 M KOH using a galvanostatic charge-discharge unit. In all the substrates the current efficiencies were more than 99% except with Pb-Sb where it was 90%. Results revealed the nature of the substrate strongly affected the morphology of the deposited material which in turn affected the electrochemical properties of the EMD samples. XRD analyses revealed that the nature of the anode did not affect the crystal structure of the deposited EMD and all the samples were predominantly ?-MnO2, which is electrochemically active for energy storage applications. The EMD deposited on lead substrate showed superior discharge capacity of 245 mAhg-1 when compared with other substrates.

Jan 1, 2014

By M. M. Holgate

"Porosity neutron deflection scales can be derived more easily by cumulative correlation than by the conventional method of plotting corresponding points on a graph. The micro-log can be used as a porosity datum for the neutron log by transforming the permeability cut-off it shows to a porosity cut-off by a permeability-porosity function obtained from core analysis. Porosity footage values calculated in this manner from the neutron log are within 20 per cent of core analysis values."

Jan 1, 1960

By D. Purdie

"This paper aims to remind researchers, designers, operators, and managers about the benefits of seeding in the design of precipitation stages in their flowsheet. Including a high density solids (HDS™) process encourages the precipitating solids to form on the surface of existing precipitated particles. This paper discusses the application of the HDS technology at Kennecott Smelter, where the authors have witnessed significant improvements in settling and filtration rates. The authors have also applied this technology at various smelter bleed treatment plants worldwide with similar improvements in precipitation and filtration rates. HDS is a registered trademark of De Nora Water Technologies. RÉSUMÉ Cet article a pour objectif de rappeler aux chercheurs, aux concepteurs, aux exploitants et aux administrateurs les avantages de l’ensemencement dans la conception des étapes de précipitation de leur schéma de traitement. L’introduction d’un procédé des boues haute densité (procédé HDS™, de l’anglais high density sludge) encourage la formation de substances solides précipitantes à la surface des particules précipitées existantes. Cet article porte sur l’application de la technologie HDS à la fonderie Kennecott, où les auteurs ont observé des améliorations importantes au niveau de la vitesse de sédimentation et de filtration. Ils ont également appliqué cette technologie à diverses usines de traitement des rejets liquides des fonderies dans le monde entier, et ont constaté des améliorations similaires en termes de vitesse de précipitation et de filtration. Le procédé HDS est une marque de commerce déposée du fabricant De Nora Water Technologies.INTRODUCTION In 1966, the lead author worked as an assistant smelting metallurgist for the Tsumeb Corporation Limited copper and lead smelter in Tsumeb, Namibia. The smelter produced copper and lead, as well as cadmium and arsenic trioxide as byproducts. The cadmium was concentrated in the lead blast furnace off gas dust, and was collected by a baghouse. The baghouse dust was leached with dilute sulfuric acid (H2SO4) in a batch process. The iron and arsenic in the solution were oxidized with potassium permanganate (KMnO4) and basic ferric arsenate (BFAS; Fe(AsO4)x(SO4)y(OH)z·wH2O) was precipitated using milk of lime. The cadmium was cemented from the purified solution using zinc dust."

Jan 1, 2018

By L. Tejeda, J. R. Donald, R. Parra, J. Duran, P. H. Lauzon

"Crucible slag tests were employed to evaluate different refractory brick classes for the Cerro Matoso electric furnace. Comprehensive analysis was conducted to evaluate the crucible erosion and characterize any slag/refractory reaction products.The classes of refractories investigated were:•,tar-impregnated magnesia;•,rebonded fused grain magnesia-chrome;•,direct bonded magnesia-chrome;•,alumina-chrome;•,picrochromite; and•,magnesia-alumina (spinel).It was concluded that tar-impregnated MgO bricks were the most suitable for the slag chemistry and furnace environment according to corrosion and infiltration resistance. A picrochromite (MgCr2O4) brick performed exceptionally well with regards to erosion resistance, however, the slag infiltrated extensively through the brick pores. Alumina-chrome, direct bonded magnesia-chromite, and spinel (magnesia-alumina) bricks were evaluated as not suitable for use in the furnace."

Jan 1, 1999