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By Harry J. Cain

Introduction The property of Pioneer Gold Mines of B. C., Limited, is located in the Lillooet mining district of British Columbia, on Cadwallader creek, 54 miles distant by motor road from Shalalth, a station on the Pacific Great Eastern railway. Milling by the present Company was commenced in 1924, a small amalgamation plant, consisting of a crusher, Bryan mill, and plates being operated until 1928. Tailing from this plant was impounded and later treated in the 100-ton continuous counter-current decantation cyanide plant which was erected during 1927-28 and placed in operation during May of 1928. A second cyanide plant, employing continuous counter-current decantation, having a nominal capacity of 200 tons, has been erected during the past few months and was put into operation during September of the present year. The ultimate capacity of the combined units of the present mill has not been determined, but it is expected to be much in excess of the rated capacity. The Ore The ore, as received at the mill, consists chiefly of quartz carrying free gold, with small amounts of pyrite, arsenopyrite, and pyrrhotite in evidence, though probably amounting to less than one per cent of the total. Some gold is very closely associated with the sulphides. The country rock is a basic igneous rock, probably an augite diorite. Near the vein it is highly altered to sericite, which slimes readily on grinding, and does not settle very well. The quartz is of two types, clear and ribbon. In the latter, the ribbons, which are not much thicker than paper, consist of shattered sulphides. In crushing this ribbon quartz, breakage is often along the streaks, exposing these shattered faces to advantage in subsequent treatment. While gold is the metal for which the ore is mined, some silver is also present and is paid for by the mint. It is, however, unimportant from a commercial viewpoint. From the standpoint of crushing and grinding, the ore might be termed 'medium 'hard'.

Jan 1, 1932

By C. R. Whittemore

PROGRESSIVE industrial organizations have recognized the importance of maintaining an adequate reference library of volumes covering all phases of their particular branch of industry, but it has been the experience of the writer that few engineers know how to use to the best advantage this store of extremely -valuable information which has been accumulated for their service. Nor does the average engineer appreciate the fact that it is only through the current technical literature that he can keep abreast of the rapidly developing fields of engineering. The present-day ramifications of the engineering field are of such wide scope that the human mind is not capable of storing away more than a small fraction of the information available on any particular topie; yet, from time ? to time, such information would prove invaluable. An engineer can know intimately only a small part of his own branch of engineering; but he cannot afford to neglect to take the fullest possible advantage of all that is already known in his own particular field. Technical information may be obtained by one or more of the following methods: (1) by enquiring of the individual who knows; (2) by performing the experimental investigations necessary to ascertain the facts; (3) by consulting the technical literature, where a record may be found of the work of others. This last method is the one we wish to examine. Our main consideration is the question of how to use the library, but first it is necessary to give some attention to the kind of enquiries one takes to the library, and to the nature of the sources of information available.

Jan 1, 1938

By Charles Amoah

Abosso Goldfields Limited has been optimizing the comminution circuit at the Damang Mine Operation for the treatment of 100% primary ore. The optimization process started at a base rate of 343 tph when treating primary crushed primary ore, and was increased to above 600 tph with partially crushed primary ore. Abosso Goldfields engaged Orway Mineral Consultants (OMC) to assist with the optimization process in 2009 and the two companies have been working together since, to further refine the process. Continuous improvement was achieved through crushing circuit modifications, changes in operating processes and grinding control system utilization. This paper discusses the improvements developed for the increase in milling capacity and improvements in final product size.

Jan 1, 2012

By A. Bowles

The process of accumulative roll bonding (ARB) has been applied to wrought magnesium alloy AZ31. Accumulative roll bonding results in severe plastic deformation of sheet material. In AZ31, this process leads to the refinement of the microstructure by dynamic recrystallization. The refinement of the microstructure results in an improvement in mechanical properties with potential for producing materials for superplastic forming. In this work AZ31 was bonded with up to 64 layers and the potential of roll cladding with aluminium was also investigated. The development of microstructure and the mechanical properties are reported here.

Jan 1, 2006

By John Redstone, André R. Laplante

"Le rebroyage des concentrés d'hématite en usine (Sidbec-Normines, Port-Cartier) et en laboratoire a été modélisé selon le modèle de Reid (1965).L'effet du pourcentage solide sur la cinétique de broyage a été étudié en usine. La fonction de sélection corrigée (pour tenir compte de l'effet du pourcentage solide sur le temps de rétention) augmente lorsque le pourcentage solide augmente de 80 à 84 pourcent. Cette amélioration est contrebalancée par une augmentation de la quantité de pulpe court-circuitée, à des pourcentages solides supérieurs a 81%. La densité optimum de broyage se situe à 84 pourcent.Comme alternative au mode d'opération actuel, l'assemblage des broyeurs en série plutôt qu'en parallèle a également été simulée. Le moins 44 µm passe alors de 68.1 à 72.5 pourcent, ce qui correspond à une capacité supplémentaire de 32 tonnes à l'heure par broyeur. Ces résultats doivent toutefois être interprétés avec prudence, car la cinétique de broyage n'est généralement pas linéaire lorsque le taux d'alimentation est plus que doublé.IntroductionL'usine de bouletage de Sidbec-Normines Inc. a été décrite par Morimoto (1977), Lévesque et al. (1979) et Pabst (1979). La section de broyage des concentrés contient six broyeurs à boulets en parallèle et en circuit ouvert, d'un diamètre de 5. 18 mètres et de 10.36 mètres de longueur. Ils contiennent chacun environ 350 tonnes de boulets d'acier forgé de 3.8 cm de diamètre. Le concentré est broyé de 10 pourcent moins 150 µm (100 mailles) à 65-68 pourcent moins 44 µm (325 mailles), à un pourcentage solide de 78 à 80 pourcent. Cette fragmentation poussée exige une consommation d'énergie de 32 kWh/tonne. Cette énergie est surtout libérée sous forme de chaleur, la pulpe étant déchargée a une température de 68-72° C. II en résulte un milieu de broyage corrosif, et une consommation de boulets élevée, de 3.4 à 4.0 kg / tonne broyée."

Jan 1, 1983

By L. C. S. Dharmasiri, S. M. Shin, A. Senaputra, J. S. Sohn, K. H. Park, J. Avraamides

Reducing agents can be applied to leach metal values from natural and secondary resources such as laterite ores and deep sea manganese nodules and recycled materials such as spent batteries / catalysts which contain high-valent metal oxides of manganese, cobalt and iron. Selective leaching of some metals can be achieved by selecting conditions to control the saturated solubility and dissolution rates of metals from oxides or mixed metal/oxide matrices. The leaching results are rationalized on the basis of chemical species, Eh-pH diagrams and heterogeneous kinetic models. The role of reducing agents such as hydrogen peroxide, sulfur dioxide and iron(II) sulphate, in acid, alkali and in the presence of complexing ligands such as ammonia for the improvement of the leaching of metal oxides and metals is discussed. Previous studies on acid leaching of metals from nickel laterites, manganese nodules and spent catalysts/batteries in the absence or presence of reducing agents show that the rate controlling step involves the diffusion of protons through a thickening product layer on the particle being leached. It is shown that the leaching of nickel and cobalt from manganese nodules and zinc-carbon batteries in ammoniacal sulphur dioxide solutions also obey shrinking core kinetics.

Jan 1, 2014

By F. Parada, R. Parra

"The neutralization process of SO2 from coal burning plants is a well-defined technology using limestone to form CaSO4 according to the following reaction: CaCO3 + SO2(g) + 1/2O2(g) = CaSO4 This paper presents the results of a study carried out to validate the option of capturing SO2 using gases from a non-ferrous smelter; SO2 content was up to 12% using a three-stage fluidized bed reactor. The difference in SO2 content affects equilibrium conditions and kinetics, rendering a direct extrapolation of the high efficiency achieved for low SO2 content impossible. The R&D program consisted of a laboratory study using a semi-pilot operation of a one-stage fluidized bed reactor and the construction and operation of a three-step reactor prototype. Results show that the reaction proceeds according to the unreacted core model that imposes a compromise between CaCO3 conversion and SO2 capture. For high SO2 capture, the calcine from the reactor contained CaSO4 and CaO. A complete capture of SO2 from gases with 8 vol.% can be achieved with a mean reaction time of two hours at 800°C."

Jan 1, 2007

By Therese Schneck

The presence of xenon isotopes from in-situ spontaneous fission of short-lived Pu244 has been confirmed in Hadean detrital zircons from Western Australia. Hadean and meteoritic zircons can retain secondary overgrowths developed after primary cristalization at 3.97-3.94 Gyr. On the moon, the metal grain in sample 66095,78 is mantled by troilite, schreibersite and cohenite. High chlorine content FeCl2 is deposited around metallic FeNi. The magnitude of Pollonium-210 to Radon-222 on the Aristarchus plateau spectrum indicates a past greater activity. The Earth Moon system from Nb/Ta systematics is consistent with a Moon iron core delayed to 3,9 Gyr.

Aug 1, 2010

By Pier-Olivier Devin, Daniel Hodouin, Maryam Sadeghi, COREM, Claude Bazin, François Lavoie

"Spiral concentrators are used for processing coal and heavy minerals such as it is the case for the concentration of iron oxide from light silica gangue. The concentration process for iron ore usually consists of a rougher bank of spirals followed by two stages of spiral cleaning. The process control applied to the concentration circuit aims at maintaining a target iron content of the final concentrate and is mainly conducted by adjusting the wash water addition and the position of the splitter gates at the discharge of the spiral. This paper describes the use of a simulator to study control strategies for a gravity concentration circuit using spirals.INTRODUCTION The Canadian iron ore mines are located in the Northern part of Quebec and in Labrador (Neal, 2000). These iron ores consist mainly of hematite with some ore bodies rich in magnetite and ilmenite. The processing of the coarse hematite iron ore consists of the extraction from an open pit mine, followed by the conventional crushing and autogeneous grinding of the ore to obtain a particle size smaller than 1.2 mm. The ground ore assaying 40% hematite (Fe2O3) with quartz (SiO2) as the main gangue is processed by spirals to produce an iron oxide concentrate assaying 90 to 95% hematite.Spirals separate the particles according to their specific gravity and size (Burt, 1984; Bazin et al., 2014). These environment friendly devices have been used for decades and are still used for the preparation of coal and for the concentration of heavy minerals such as iron oxide (Staff, 1977; Wills, 1992). However very little information is available concerning the control of gravity concentration circuits. This paper analyzes the control practice of a gravity concentration circuit using a simulator. The paper consists of 3 sections. The first section describes the operation of spirals and spiral concentration circuits. The second section briefly describes the simulator and shows some simulation results for a gravity concentration circuit. The third section shows the application of the simulator for the study of control strategies for a spiral concentration circuit."

Jan 1, 2016

By Louis Frost

"1N 1951, the Dominion Steel and Coal Corporation, as part of a programme of modernization in their coal mining operations at Sydney Mines and Glace Bay, Nova Scotia, undertook the development of two large cross-measure tunnels, which were to be used for the purpose of raising the coal from the underground workings by conveyor belts direct to wash plants located on the surface.These tunnels were to reach from the surface to central loading points underground located at a depth of 600 and 900 feet, respectively. They were to be driven on a pitching gradient of 11 degrees to the horizontal, and they were to reach a length of 3,600 feet in the Sydney Mines area and 10,000 feet in the Glace Bay area.The longer tunnel, 19 feet in diameter, was driven a distance of 1,500 feet and, for domestic reasons, bas not yet been •completed. The other tunnel, in the Sydney Mines area, 18 feet in diameter, is steel supported and concreted throughout its entire length. This tunnel has been completed and will be in operation at an early date.The development of this particutar tunnel posed an additional problem, as the rock through which it had to pass was considered to be water-bearing. In the sinking of Princess Colliery shafts in 1866, a great deal of water had been encountered, and it had been necessary, while sinking, to line the shaft with cast-iron tubbing through the water-bearing strata. The shaft had to be lined for a depth of 300 feet at the upper end. It was anticipated that we would meet with difficulty in driving the tunnel through this strata."

Jan 1, 1955

By M. Abdellatif

Successful demonstration of The Mintek Thermal Magnesium Process (MTMP) was achieved in November 2004 at the pilot-scale, About 30 tons of magnesium producing recipe was smelted in the DC arc furnace over a continuous operation of 8-days, Twenty-two furnace batching-tapping operations were carried out at a feed rate of 525kg/h and a smelting temperature of 1600-1700°C, The MgO content in the produced slag was as low as 6,7%, and averaged 9,2% MgO, resulting in an overall magnesium extraction of 77%, which reached 87% during good operating periods, Magnesium vapour was extracted at a rate of 70-85kg/h and was delivered to the condenser that was operated at 680-720°C, The magnesium was captured in the condenser crucible in a liquid state, allowing its prompt tapping, More than 3500kg of crude metal were produced over 15 on-line metal tapping operations, On average, a condensation efficiency of 85% was achieved during the entire testwork, which peaked at 87% during steady operations, The quality of the crude metal was similar to, if not better than, that of the Magnetherm's crude magnesium, A pre-feasibility study has indicated that the MTMP has the potential for lower capital and operating costs as compared to the electrolytic process, and therefore Mintek and its consortium partners are exploring opportunities for a commercial production facility.

Jan 1, 2006

By Q. H. Bui

The elastoplastic self-consistent model is one of the effective models to study the initial microstructure effect on the mechanical behavior of bulk materials. However, the use of this micromechanics-based model which takes into account only the Hall-Petch relationship at grain level for predicting the grain sized effects on the strength of the deformed materials is not accurate yet because of the fact that the dislocation density contributes also to the strengthening of this kind of materials. In this study, a modification made to the Hill-Hutchinson elastoplastic self-consistent model was proposed for investigating the microstructure dependence of the mechanical behavior of cold-drawn 6063 aluminium tubes. Because of the novel modification, an estimation procedure with two steps was required to identify the parameters of this micromechanical model. An acceptable agreement between experimental and theoretical stress-strain curves was achieved.

Jan 1, 2011

By Jing Chai

The Cenozoic unconsolidated strata with the thickness of 100 to 240m in the east area of China are composed of clay, sandy clay and hardpan, etc. Numerous shafts of the coal mines in these areas have been damaged to various degrees since 1987, with the main reason for this being the subsidence of the super-thick unconsolidated strata. To prevent the continuing settlement deformation of unconsolidated strata caused by groundwater removal, long-term water injection through multiple boreholes controlled the settlement deformation of unconsolidated strata. A new type of fiber Bragg grating (FBG) sensing system was successfully used for real-time strain monitoring of the unconsolidated strata during water injection at a coal mine in China. A mathematical model for the compression settlement induced strain calculation is proposed which can assist understanding of the effect of water injection on the ground. With the increase in water injection, the unconsolidated strata compressed state was improved by the transition of the stress state from compressive to tensile stress. The wavelength change of fiber Bragg grating sensors corresponded with the trend of the water level in the same strata. Engineering practice indicates that these sensors can normally, safely and reliably survive conditions associated with hydrous unconsolidated strata. The FBG sensing can be used for continuous lifetime monitoring of the system, starting with real-time monitoring during low-pressure water injection process of multi-borehole. The results will give important guidance for water injection and mastering stratum subsidence.

Aug 1, 2013

By D. G. Eskin

"It is well known that it takes some time for the solid phase to completely dissolve upon melting, especially inside the defects of insoluble particles, e.g. oxides. Until then the oxides remain active solidification substrates in the case of subsequent solidification. It is also known that ultrasonic melt treatment causes grain refinement through activation and dispersion of solidification substrates (one of the mechanisms) and also accelerates the dissolution of solid metal in the melt. In this study we combine these effects and demonstrate that the introduction of an alloy rod into the matrix melt of the same composition results in significant grain refinement, this effect being increased by the ultrasonic vibration of the rod. The achieved grain size is comparable to that obtained by a standard Al–Ti–B grain refiner. All samples were cast using a standard TP-1 mould to enable correct comparison. The effect of the temperature range of the rod introduction, as well as the effect of ultrasonic vibrations are discussed.INTRODUCTION The fact that by introducing solid metal into the melt one can achieve structure refinement is rather well known. As early as in the 1930s–1950s a series of papers and patents have been published, showing the benefits for grain refinement when dissolving solid metal in the melt before solidification (Danilov and Neimark, 1938; Scheil, 1956). Later on this way of structure refinement was developed further and dubbed “suspension casting” or introduction of “internal chills” (Madyanov, 1969; Zatulovsky, 1981). The solid metal was added in a form of cut wire, cut sheet, or powder, with the resulting grain refining, elimination of columnar grain structure in ingots and castings of steel, copper and aluminium alloys. The underlying mechanisms have been suggested as (1) rapid cooling of the melt due to the latent heat consumption upon melting of the solid metal with the resultant melt undercooling and (2) introduction of many solidification substrates in the form of crystal fragments and active non-metallic inclusions (Danilov & Neimark, 1938; Balandin, 1973). A number of patents have been filed where either the same solid alloy or a master alloy with additions (e.g. Ti for Al alloy) is introduced in the amounts up to 50% (typically less than 10%) into the melt close to the liquidus temperature (Schmidt, 1966; Talbot & Soller, 1973, Krupp, 1974; Bondarev, 1979). The main reason that this technique is not widely used in industry is the possible incomplete dissolution of the solid parts introduced into the melt with ensuing inhomogeneous as-cast structure and potential defects. Also the selection of the temperature range where the technology works the best is not clear."

Jan 1, 2018

By Minerals Refining Company, Gerald Luttrell, Biao Li, Robert Bratton, Roe-Hoan Yoon, Stan Suboleski, Nikhil Gupta

Flotation is regarded as the best available method of upgrading coal and mineral fines in the mining industry. However, its efficiency deteriorates rapidly with decreasing particle size. Furthermore, ultrafine concentrates are difficult to be dewatered economically. Due to these technological problems, some operators are forced to discard at least part of the ultrafine materials to tailings (or refuse) ponds, causing significant losses of valuable resources and creating environmental concerns. To address these technological issues, a new separation process named hydrophobic-hydrophilic separation has been developed on the basis of the recent advances in the science of hydrophobic interactions. The results obtained to date show that the process can recover and dewater ultrafine particles simultaneously with high separation efficiencies. Following a series of extensive laboratory tests, the process has been scaled up to proof-of-concept and pilot-scale continuous tests. The results obtained with desliming cyclone overflows, screenbowl effluents, and by-zero coal flotation feeds can be cleaned to less than 4% ash and moisture with over 97% organic matter (or coal) recoveries. The results obtained with mineral fines also showed encouraging results.

Jan 1, 2016

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 H. Salamanca

Recently, the mining industry has become one of the leading target markets for the technology industry as they need to innovate in their productive processes in order to boost productivity, reduce operation costs, increase operation safety, and improve the quality of life of their workers. This work presents the technological developments that HighService has done in different stages of the mining productive processes to include robotic manipulators in their automation solutions as well as the development of new equipment and sensors. The robotic technology integration is presented in different applications such as handling and selection of cathodes in E-W machines, automation of base plate maintenance, automation of cathode stripping machine, and multi-tools handler for liner bolt replacement in SAG mill liner maintenance activities. The proposed solutions show technical and economical viability with low initial investment and short implementation period of six (6) to ten (10) months. The results have been validated in plant, obtaining higher production rates and availability.

Jan 1, 2007

By P. Tracy

An advanced real-time monitoring system, called a "Tapblock Diagnostic System" is under development to help furnace operators manage the operation and maintenance of their tapblocks. The life of a water-cooled tap block in a smelting furnace ranges from several months to several years, depending on the operating conditions. Tapblocks are typically replaced at regular maintenance intervals; a strategy based largely on historical records and not on the actual condition of a particular tapblock. The Tapblock Diagnostic System monitors the tapblock throughout its life and accumulates probable wear events to help the operator assess the residual integrity of the tapblock. Benefits of this system include the ability to provide early warnings of tap block wear to provide improved safety and maintenance planning. Using cooling-water flow together with copper and water temperature measurements, the system performs calculations that compare the present tapblock performance with the expected operating envelope using a multivariate statistical method (Principle Component Analysis). The operating envelope is pre-calculated for a wide range of operating conditions using transient thermal modeling (Computational Fluid Dynamics). A state indicator in the form of a green, yellow and red light is used to inform operators of the tapblock performance and health status.

Jan 1, 2007

By Marc C. Bétournay

A number of successful proof-of-concept projects have been carried out to replace conventional power application, such as diesel and rechargeable batteries, in underground mine vehicles. This has led to the development of the world?s first fuelcell production vehicle, a mine locomotive. A mine loader project has also started and several other projects are planned. These projects are providing the mining industry with the required information to make this technology shift possible. The application of fuelcell power will yield several important benefits such as the elimination of underground diesel emissions, significant reduction in the primary extraction?s sector greenhouse gas emissions and support for a more productive scenario. This article reviews these successes, discusses ongoing and potential projects and presents the technology application benefits that could be possible for mining operations.

May 1, 2003

The control of AG mills fed by ores with harder and softer components can be challenging due to the sensitivity of the mill to the ratio of hard to soft components. The mills at LKAB?s iron ore operations are generally well controlled, but there are periods when the throughput falls off dramatically, due to a loss of mill filling. As the ore is upgraded in the sorting plant through magnetic separation prior to milling, this presents an opportunity to manipulate the feed blend in advance. In order to assess this opportunity, a fullscale mill charge was dumped and assayed by size to quantify the build-up of competent waste in the mills. This was supplemented by pilot and locked-cycle laboratory tests at a wide range of feed blends in order to facilitate the development of an appropriate multi-component AG mill model. This paper reports the experimental campaign requirements and methodologies, as well as the major outcomes from analysis and modelling exercises using the industrial, pilot and laboratory multi-component data.

Jan 1, 2012