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To date, improved thickening of clay mineral dispersions presents major technological and environmental challenge to mining and mineral processing industry worldwide. Flocculant-assisted dewatering processes currently employed during thickening are far from being efficient, requiring further development and process optimisation for dramatic improvement. In this paper, recent studies carried out to modify (i) pulp chemistry, (ii) flocculation performance and (iii) particle interactions to significantly improve the dewatering behaviour of flocculated, model and plant smectite and kaolinite clay dispersions are presented. It is shown that pulp pH-mediated hydrolyzable metal ion hydrolysis and specific adsorption in tandem with high molecular weight flocculant and shear may synergistically act to significantly enhance the dewaterability of both clay mineral pulps. Furthermore, polymeric flocculant structure type is demonstrated to show clear links with floc shear sensitivity, and hence, flocculation performance and pulp dewaterability. The implications and relevance of the findings plant clay mineral waste tailings thickening operations are drawn.

Jan 1, 2006

By B. Arlyuk

The complex system has been developed for long-term assessment of world prices and sale volume of primary aluminium when using the analytical model of the market and market supply forecasts as well as economy development in the Western countries characterized by the industrial production indices as correct data of Western World aluminium consumption are absent, The important part of this system is the model developed for forecasting the degree of capacities utilization of smelters and refineries depending on the price level, The model contains a statistic part corresponding to the capacities distribution by the production cost, and a dynamic part determining the deviation from the static depending on the price variation dynamics, The developed complex system has been identified by the actual data of the world prices of smelter grade alumina and primary aluminium, conservation and reactivation of refineries and smelters in the Western countries within the period from 1992 to 2003. The system was used for primary aluminium and alumina price forecasts till 2020.

Jan 1, 2004

By W. L. Ennis

Introduction This paper outlines the causes of underground fires at Noranda Mines and the precautionary measures taken to guard against such fi res. Shafts There are six shafts (Figures and lA) on the property, of which N os. 1 and 2 are abandoned. Nos. 3, 4, and 5 are the present working openings from surface and No 6 is an internal shaft. No. 3 is used primarily as a service shaft, while Nos.?1 and 5 are the main hoisting shafts. Orebodies The orebodies are of two distinct types. There are the massive sulphide bodies, and the areas of mineralized rhyolite containing gold values and a silica content high enough for fluxing purposes. The massive sulphide bodies contain chalcopyl'ite, pyrite, pyrrhotite, and minor amounts of sphalerite and magnetite. The concentration of particular sulphides varies even within the same body. It is the areas high in pyrite, and to a lesser degree those, high in pyrrhotite, that are of particular interest.

Jan 1, 1950

The dissolution of chalcopyrite has received a significant amount of attention. The predominant paradigm of investigation is that its rate of dissolution is limited or passivated by a surface coating or film of material. The common candidates for such a passivating coating are numerous: polysulfide coating, metal deficient layers, copper sulfide coating, bornite layers, jarosite precipitates, and elemental sulfur films. While this line of explanation, that is, the explanation based on passivation, seems to have won some form of consensus with researchers, there is another explanation for the results that can account for all the results observed. Crundwell (1988) proposed that the solid state properties of chalcopyrite, in particular, the semiconducting properties, are responsible for the observed behaviour of chalcopyrite. The purpose of this paper is to outline the semiconductor mechanism of dissolution, and to show how this mechanism accounts for all the observed phenomena recently reported in the literature. The paper outlines the semiconductor mechanism of dissolution, shows how this mechanism accounts for the dissolution

Jan 1, 2014

By C. Samuelsson, G. Carlsson

Characterization of dust from Boliden Mineral AB’s copper-plant in Sweden was carried out using chemical analysis, X-ray diffraction analysis, energy dispersive analysis and wave length analysis using electron microprobe equipment. Dust from four different locations was characterized: the electrostatic precipitator (ESP) after the roasting furnace; the ESP after the copper smelting furnace; from the copper converter ventilation bag house filter; and from the bag house filter collecting dust from the settling furnace and tap gas ventilation. The results showed that the dust is composed of small solid and/or liquid particles from the furnace reactor which have been transported with the process gas to the dust collecting devices. This portion of the dust is mechanically formed. It also contains compounds that have been vaporized in the process and then condensed from the process gas at lower temperature, chemically formed dust. The proportion of mechanical and chemical dust varies with the process generating the dust.

Jan 1, 2001

By J R. O Walli

Large production shafts can be successfully sunk through the ubiquitous Blairmore formation of southern Saskatchewan by employing the freezing process and by the installation of a cast iron tubbing lining. Although the freezing technique for shaft sinking and the use of cast iron tubbing to preserve the shaft are new to the North American continent, these procedures have been employed in Europe for the past eighty years. More than 200 shafts, covering a wide variety of ground conditions, have been sunk by the freezing process, and most of these have been lined with cast iron tubbing. The No. 1 shaft of International Minerals and Chemical Corporation, near Esterhazy, Saskatchewan, comprises the first major example in Canada of the employment of European methods to overcome extremely difficult ground conditions. The Blairmore formation was solidified by the deep freezing process, employing a lithium chloride solution as the refrigerant, with input temperatures ranging to -55°F

Jan 1, 1964

Lonmin RoM ball mills are treating two types of feed ore produced by conventional mining and mechanised mining methods. It was reported that reduction in mill throughput was observed when treating the mechanised mining ore. Detailed grinding surveys were conducted for troubleshooting. Ore samples were collected for breakage characterisation using a JKRBT based on different particle density components. XRD analysis was conducted to investigate the association of minerals with density components. The plant surveys and the breakage characterisation tests all suggested that the two mining methods did not significantly affect either the ore breakage properties or the RoM mill performance. Instead, the mill discharge open area exerted a remarkable influence on mill throughput. The RoM ball mill operated at Lonmin K4 Concentrator has been proven to be a versatile mill that performed stably with variations in feed size distribution and feed ore changes by different mining techniques. The reasons are elucidated by the multi-component breakage characterisation and the plant surveys data.

Jan 1, 2012

By B. J. Walsh

ABSTRACT Segregation of sphalerite minerals in zinc concentrates into christophite, marmatite and ordinary sphalerite by means of magnetic fractionation is investigated. A Frantz ferromagnetic filter, 1.2 amp., and a Dings magnet, 0.3 amp., is used to fractionate seven zinc concentrates produced in the Province of Quebec. The Dings magnetic product contains the pyrrhotite, and the sphalerite as christophite. The Frantz magnetic product contains sphalerite as marmatite, while the Frantz nonmagnetic product contains ordinary sphalerite. The results indicate that the magnetic susceptibility of sphalerite increases with increasing isomorphous iron content and that a satisfactory separation into christophite, marmaite, and ordinary sphalerite may be accomplished by magnetic fractionation. INTRODUCTION SPHALERITE, the chief ore of zinc, is almost never pure zinc sulphide. Iron is almost always present isomorphously replacing an ?equivalent amount of zinc. What may be referred to as 'ordinary' sphalerite contains up to 10 per cent iron. More highly ferriferous varieties, with 10 to 26 per cent or more iron, have been named marmatite .and christophite.

Jan 1, 1951

By G. J. Govett

THE RESERVES of industrial minerals of the Western Plains are probably several times more valunable than all the known deposits of metallic minerals of the Canadian Shield, though sharing little of the latter's popular appeal. Because of comparatively low value per unit weight or volume, an adequate and accessible supply of industrial minerals is essential for the full development of any territory; assessment of the value of deposits should consider fully the proximity to cheap transportation, and existing and potential markets. Production statistics of industrial minerals are probably a more reliable guide to economic development than, for example, those of petroleum, and the relative importance of industrial minerals increases with growth of the population. The development of a high-volume natural deposit such as petroleum naturally favours an increase in population, and thus industrial minerals form an integral part of an expanding industrial economy. This situation is clearly demonstrated by the relationsl1ips of industrial minerals production, petroleum production, and population growth, in Alberta (Figure 1).

Jan 1, 1959

By E. C. W. Perryman

BEFORE describing the methods used for fabricating uranium into various shapes and sizes it is necessary to illustrate briefly the unusual conditions under which uranium has to operate when used as a fuel element in a reactor. During reactor operation, for every fission that occurs two atoms of intensely radioactive fission products are produced together with two or three neutrons. The neutrons that are ejected possess several m.e.v. of energy and when one of them strikes an atomic nucleus, that atom acquires up to 105 e.v. of kinetic energy. This is large enough to displace the atom from its lattice position and send it shooting through the crystal, displacing other atoms out of their lattice positions. The net result is that a large number of vacancies and interstitial atoms are formed within the crystal lattice which sometimes have profound effects on the physical and mechanical properties of the material in question.

Jan 1, 1957

By Wm. D. Jr. Sheldon

THIS paper presents practical data to aid in the selection of a mine ventilating fan, and outlines considerations to be made to ensure satisfactory operation and optimum efficiency of the fan. Much has been published on the general subject of mine ventilation, but the writer has found few specific data on factors and considerations which govern the selection of a fan-data which should be available to the operator if his fan is to give satisfactory service within the range of the high-efficiency portion of its performance curve and deliver the specified air capacity when operating against the anticipated range of resistance of the mine. The total quantity of fresh air furnished by the ventilation system must be adequate to provide, and to ensure at all times, safe and healthful working conditions in the mine. It is assumed that the mine operator is able to determine the air quantities required for the various parts of the mine.

Jan 1, 1941

By S. Southall, F. McCaffrey, F. Stober, M. Darini

Electrode Columns are commonly used in electric furnaces to deliver current and regulate furnace power to the smelting or melting process. Hatch has developed an innovative patent-pending system for lowering ("slipping") and/or raising ("back-slipping") the electrodes through an electrode column, without requiring the release of any clamping devices. All clamping forces are applied by springs. Unlike systems employing hydraulically applied clamping forces, (e.g., water bladders) the spring system is failsafe. Its inherent simplicity virtually eliminates the need for maintenance. The Hatch system is particularly applicable to Soderberg electrodes, and comprises two axially movable slipping clamps and a stationary power clamp, each of which apply a distributed, radial clamping force to the electrode. The magnitudes of the slipping sleeves' clamping forces and sequencing of their axial movements are selected such that the slipping clamps, in conjunction with the weight of the electrode, provide slipping or back slipping without release of any clamping force.

Jan 1, 2005

By X. Q. Jiang, D. L. Chen, A. Macwan

Magnesium alloy, being the lightest structural material, is a key candidate for the weight reduction of vehicles in automotive and aerospace industries; however, its poor corrosion resistance and difficulty in deformation are limiting factors. Recently, Al/Mg/Al tri-layered clad sheets have been considered as a promising alternative to improve corrosion resistance and formability of magnesium alloys. The aim of this study was to evaluate the tensile properties and deformation behavior of Al/Mg/Al tri-layer clad sheets at different temperatures and strain rates. Yield strength (YS), ultimate tensile strength (UTS), and elongation were observed to increase with increasing strain rate. With increasing temperature from -40°C to 180°C, YS and UTS decreased and ductility increased. The strain hardening exponent evaluated via three equations of Hollomon, Swift, and Afrin et al. showed a similar increase with increasing strain rate and decreasing temperature. The fractographic analysis showed partial debonding of clad interface especially at higher strain rates and lower temperatures.

Jan 1, 2015

By W. J. Stickney

"Over-all recovery of cadmium has been increased at the plants of the Hudson Bay Mining and Smelting Co., Limited, since the construction of a slag fuming plant and baghouse where smelter flue dust is recovered. This pa-per outlines the distribution of the cadmium in plant products from the concentrator to the refining department.The leaching of cadmium-bearing precipitates from the zinc plant is also discussed. This consists of a two-stage leach; first with sulphuric acid and then with copper sulphate. Details of the leaches are outlined along with the safety measures practised in handling the hydrogen and arsine evolved.The paper describes the final preparation of electrolyte for the refining cells by purification for copper and thallium. Deposition of cadmium, using a polyacrylamide as an addition agent, is discussed.An outline is given of the melting procedures, under either sodium hydroxide or zinc chloride, and of the sub-sequent treatment of the dross to recover entrained cadmium and thallium."

Jan 1, 1966

By R. A. L. Drew, F. Jalilian, M. Jahazi

Joining of superalloy Inconel 61 7 with a foil interlayer using transient liquid phase bonding (TLP) technique was studied. Inconel 617 is a solid solution, Ni - Cr - Co- Mo alloy with an exceptional composition of high temperature strength, oxidation, carburization resistance and thermal stability. In this investigation, two bonding temperatures, 1065°C and 1150°C, and two interlayer thicknesses with joining times varying from 5 minutes to 24 hours were employed. Experiments were carried out using nickel base interlayer (A WS BNi-3) with boron as the melting point depressant (MPD) element. Joints were characterized using optical microscopy, SEM, FEG-SEM, EBSD, XRD and microhardness. The results indicated that the rate of elimination of the liquid phase with increasing the bonding temperature, holding time and decreasing the thickness of the interlayer increased. The main precipitates in the diffusion layer had platelike and blocky morphologies for both bonding temperatures and all holding times.

Jan 1, 2006

By L. I. Kiss, A. Larouche, V. Dassylva-Raymond

Control of the quenching capacity of the cooling water is of primary importance for maintaining the quality and recovery rate of ingots produced by direct chill casting. Industrially, this can be done using a cylindrical metallic probe undergoing rapid quenching by direct immersion in a reservoir filled with casting water. Such a test rig originally developed at Alcan Arvida Research and development Centre was modified and used to assess the role of key parameters affecting the boiling heat transfer. During the tests, the probe of the instrument undergoes the effects of different heat transfer mechanisms. An experimental study was performed in order to clarify the details of the probe-water heat transfer during rapid quenching. The heat flux along the surface was determined by mathematical modeling using the measured temperature signals, while the corresponding heat transfer regimes like stable and unstable film boiling, nucleate boiling and natural convection were identified by the analysis of high-speed video recordings. Aluminium

Jan 1, 2006

By Young Hyun Paik, Hyung Sup Choi, Yeun Sik Kim

The basic studies on the surface properties and flotation characteristics of ilmenite were made by electrophoretic, adsorption, contact-angle and floatability measurements. The isoelectric point of ilmenite is found to be at pH 5.6. By combining the results of electrokinetic studies and adsorption measurements, a clearer picture of the ilmenite-solution interface was observed. These findings were correlated with the floatability of ilmenite obtained by Hallimond tube tests. The general flotation characteristics of ilmenite are compared with those obtained for magnetite and rutile. It is indicated that the above three minerals, namely, ilmenite, magnetite and rutile, have very similar surface properties and flotation characteristics. Therefore, it is difficult to make an effective separation of these minerals by flotation. However, it is found that sodium orthophosphate acts as a selective depressant for magnetite in anionic flotation. Therefore, close pH control of the pulp in the presence of the phosphate ion enhances the possibility for a successful separation of these minerals.

Jan 1, 1967

There are many inherent risks in creating a mine plan for a new ore zone in an underground mine; one of such risks is the redistribution of stresses that could be a cause of instability. Using numerical modelling tools, it is possible to model the planned stope extraction sequence and evaluate the influence of mining induced stresses on the stability of remnant pillars, and use this information to remedy potential setbacks. This paper demonstrates this approach through a case study of the short-term mine plan of the Lapa mine of Agnico Eagle Mines Ltd., an underground gold mining operation near Val d?Or. Three-dimensional boundary element modelling is used to compute the stresses induced by the stope extraction sequence as planned with a longitudinal retreat mining method. The proposed methodology can be generalized to other mines that require an understanding of the stress concentrations at the pre-feasibility stage of mine design.

May 1, 2009

By S. Khoshkhooei

In this research, the effects of rare earth elements addition on thermal fatigue behaviors of AZ91 alloy were studied. Repeated heating and cooling cycles were applied on the samples at 170°C and 210 °C to develop thermal fatigue cracks, Crack growth mechanisms and microstructural influences were investigated by optical and scanning electron microscopy (SEM) as well as energy dispersive X-ray spectroscopy (EDS), Thermal fatigue behaviors were improved successively by addition of up to 2-wt% RE, This improvement is attributed to consummation of the aluminum of the melt by precipitation of the needle shape Al 11 RE3 phases, This process reduces the volume of Mg17Al12 phases and consequently decreases the brittle Mg/Mg17Al12 interfaces which are the main reason of weak thermal properties of the alloy at rather high temperatures, Further additions of RE, however, reduced the thermal shock resistance of samples by increasing in the mean length of the brittle needle shape phases.

Jan 1, 2005

By S. Kashani-Nejad

The formation of oxides during the dehydration of MgC12,6H20, Bischofite, was studied by heating the bischofite over a range of time and temperatures in ambient atmosphere. Using a methanol-leaching technique developed by authors, the oxides that formed were isolated, identified and assayed. Three distinct regions of oxide stability were identified. The oxide produced at dehydration temperatures less than 300 °C was Mg2(OH)3C1,2H2O; at 300 °C, mixtures of MgOHC1 and Mg2(OH)3C1.2H2O were formed and at 400 °C, MgOHC1 was the only oxide produced. The presence of MgO observed in the products of the dehydration of bischofite at temperatures above 400 °C was due to the thermal decomposition of the MgOHC1 that was formed while the sample was heating to over 400 °C.

Jan 1, 2006