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By Ning Zhang, Yan Chen, Qikang Yi, Linjian Ma, Guoan Wang

Laboratory tests were performed to explore the effects of frequency on the deformation property of rock salt subjected to cyclic loading under confining stress condition. A two-stage (transient and steady) evolution law of axial cumulative strain was obtained through cyclic stress-strain curves complied from the loci of minimum load of each cycle. The unloading modulus decreases with loading cycles/time as a negative exponential function. The damage of rock salt under cyclic loading is reflected by the degradation of elastic modulus. A unified damage evolution equation considering the effects of frequency and time was established based on the experimental results. A new creep damage model for rock salt was proposed by introducing the non-stationary modular components in Burgers creep equation according to the Lemaitre equivalent strain theory. Comparative study indicates that the new model can accurately describe the creep deformation and damage evolution of rock salt under different loading frequencies. This paper provides a more reasonable model and relevant mechanical parameters for the stability analysis of compressed-air storage cavern in the injection and withdrawal durations.

Jan 1, 2015

By Bunting S. Crocker

This paper reviews the trends in the past two years in autogenous grinding throughout the world. It covers rock grinding in South Africa, Sweden, Canada, the United States, Finland and Germany. To properly orient the discussion on this subject, the paper attempts to define and classify the scope of autogenous comminution. As this is a relatively new subject, there is often considerable confusion regarding the various practices, which sometimes differ widely. By clarifying the types and forms, we hope to help clear up this con-fusion. Autogenous grinding is being carried out, throughout the world, either in mills grinding in water or solution or in dry mills using air classification to remove the finished material. The wet grinding, particularly, can be divided into: (1) (2) (3) Primary autogenous grinding, or "run-of-mine" grinding. Secondary autogenous grinding or semi-autogenous grinding or rock pebble grinding. Combination processes. -This covers plants in which pebbles made in the primary mill are re-moved and used as grinding media for fine grinding in secondary mills.

Jan 1, 1963

By C. Chapman, M. G. Reading, M. P. Amsden

Ecstall Mining Limited, a subsidiary of Texasgulf Incorporated, operates the Kidd Creek mine, a 10,000- tpd base metal producer, near Timmins, Ontario. Two different ore types are mined and milled copper-zinc and silver-lead-zinc. At the highly automated Ecstall concentrator, the ores are processed by selective flotation in three individual circuits. One of the most important metallurgical tools for process control is a sample system incorporating continuous onstream X-ray analysis. Recently this system was further automated by adding computer control of reagents for two copper-zinc flotation circuits. The computer programs, utilizing optimum seeking methods and smelter contract terms, have increased copper recovery 0.8% and zinc recovery 1.6%, and reduced reagent costs by 12%. Although not anticipated, copper and zinc concentrate grades were improved modestly as well.

Jan 1, 1973

By W. G. Worcester

IN the presentation of this paper to the Institute, three objects are in the mind of the writer: first, to set forth the close relation which, of necessity, exists between ceramics and the industrial minerals; second, to clarify the apparently hazy understanding which many have of ceramics in general; and lastly, of equal or even more importance, to stimulate a greater interest in the industrial minerals, especially in those used and required by the ceramic industries. While Canada is now producing in large quantities a fairly wide variety of the ceramic industrial minerals, there are some which are not known to occur in the Dominion. Hence it is to be desired that our geologists, prospectors, and others, while on field work, should be on the look out for commercial deposits of such minerals as diaspore, bauxite, ucts of a value in excess of $600,000,000, a figure which places ceramics as kyanite, massive topaz, and sillimanite. A find of any of these in quantity would prove of very great importance and value to the country as a whole. At this point it seems desirable to introduce formally the word ceramic or the plural of it, ceramics. In doing so it may be stated that the origin of the word dates far back in history in that it was derived in part from the Greek word Keramos, 'a potter' or 'pottery', which in turn has been traced back to an older Sanskrit root meaning 'to burn' or 'burned stuff', having reference, no doubt, to burned pottery or other clay wares; and the word was so used until near the close of the last century, when the world's first schools of ceramic engineering were established in the United States. The use of the term ceramics was then expanded to cover a much larger field the entire field of the silicate industries and products. At one time it was suggested by a limited number of ceramists that the term 'ceramic engineering' be changed to 'silicate engineering'. This proposal, however, gained little support and was soon abandoned.

Jan 1, 1945

By T. V. Simpkinson

Abstract A brief history of the electric arc furnace process of steel-making is given. The greater relative importance of this method of steel manufacture to the Canadian steel industry, as compared with its importance in the steel industry of the United States, is shown. The scope of the process is outlined and brief mention is made of the difficulty of obtaining melting stock low in alloy content. The physical chemistry of steel-making is discussed at length in simple terms, with emphasis on oxidation, de-oxidation, and the role of hydrogen. Carbide-type and silicon-type slags are described and the particular usefulness of each is outlined. The importance of various factors in the melting practice is evaluated on the basis of practical experience. Introduction Although electric furnace steels constitute only a small portion of the total weight of steel used in industrial operations, their importance is relatively much greater than is indicated by comparative tonnage figures. Tool steels, which are vital to all industry, are made almost exclusively by the basic electric arc furnace process, as are stainless steels, valve steels, and the higher alloy types of the class usually referred to as "alloy steels'. For many applications where steel other than electric furnace quality is often used, and when first cost is secondary to performance in service, the extra steel cost of electric furnace quality material is usually returned with interest by consistently longer service life. The electric furnace is pre-eminent in the quality alloy steel field because of the control that may be exercised over conditions of oxidation, de-oxidation, and temperature, the fundamental operations in steel making.

Jan 1, 1948

By M. A. Clayton, D. Kinakin

The Mitchell Creek Landslide is a large, structurally controlled, complex bedrock instability located in northwestern British Columbia. Characterization of the landslide using aerial photograph, exploration geology, and geotechnical investigation data has been completed allowing the development of a three dimensional conceptual model of the landslide domains and slope behaviour. Three domains have been identified in the landslide, from top to bottom: the Sliding domain, a relatively intact slab slowly sliding into the valley; the Transition domain, located in the mid slope of the landslide and showing evidence of significant extension and continuing to subside and displace into the valley; and a Toppling domain, at the toe of the landslide in an area of overturned foliation. Movement is greatest in the Toppling domain, with long term estimated rates of movement up to 4 times that of the Sliding domain; the Transition domain exhibits the greatest range of displacement rates, with average long term values approximately double the slower Sliding domain. This paper documents the results of numerical modelling of the Mitchell Creek Landslide with variation in geomechanical properties, basal rupture surface configuration, structural fabric, and pore water pressure conditions. The locations of internal shear surfaces within the landslide have been estimated from surface scarps, structural fabric orientation, and borehole monitoring data. The performance of each numerical model was evaluated against observed behaviour of the landslide. The configuration and properties of the basal rupture surface were identified as critical to model behaviour, as was spacing and location of internal structures.

Jan 1, 2015

By G. M. Dunn

Pressure leach autoclave circuits are employed in the leaching of ores, concentrates, mattes, alloys and intermediates for the recovery of metals into solution. Once the metals are extracted into solution the value metals can be recovered by hydrometallurgical means such as by purification followed by electrowinning, hydrogen reduction, pyrohydrolysis, crystallisation and other unit operations. In many of these integrated flowsheets the pressure leach step is pivotal to the recovery of the value metals from the host material. In an expansion or a new project, a large component of the capital cost can be associated with the pressure leach step and process engineers frequently look for opportunities to mitigate costs. This paper examines a new route for increasing the capacity of an exothermic pressure oxidation leach for sulphide concentrates, sulphide and phosphide mattes and alloys.

Jan 1, 2004

By S. Kelebek, U. Demir, T. C. H. Richards, E. Koss

"Laboratory-scale tests were carried out to investigate the response of a high-grade (~143 g/tonne) well-liberated gold ore to flotation using two collector types. Octyl and amyl xanthates, representing conventional types of collectors, were tested against an n-octanoic and hexanoic acids under moderate and high redox potential conditions. The latter was based upon a suggestion in literature that monocarboxylic acids are able to adsorb onto the surface of gold at redox potentials near 600 mV (SCE). This investigation did not demonstrate that these carboxylic acids could function as collectors for gold in real ores. In fact, they appear to have slightly depressed gold. However, the results demonstrated that octyl and amyl xanthates acted as highly effective gold collectors for this ore and that an increase in the collector dosage led to an increase in recovery for all mean particle sizes. In some tests, gold recoveries of around 95% were attainable in concentrates with grades around 6 kg/tonne, indicating that xanthate flotation remains a viable means of concentrating gold even at coarse grain sizes. Various aspects of the process such as grade-recovery performance and recovery by size are discussed.INTRODUCTION Three methods are used for the recovery of gold in mineral processing, either alone or in combination: gravity concentration, cyanidation and flotation. Gold occurs as a by-product in some ores together with platinum group metals and as the primary metal in other ores in the form of native gold and electrum, which are alloys of gold, silver and minor amounts of copper. Flotation is a viable method for recovering liberated gold where the gold is visible under an optical microscope (greater than 1 µm in size) and where the attachment of gold grains is not prevented due to bubble loading by competing minerals. It is generally known that grains finer than 150 µm in size will float with most collectors."

Jan 1, 2017

By G. Reuben Yourt

IN 1935, Wright-Hargreaves Mines, Limited, initiated an enlarged programme of ventilation. In the mine, surveys were made from time to time by the geological staff, and improvements in ventilation were effected to accord with progress in mining as greater depth was attained. In the summer of 1938 an engineer was trained in the technique of dust sampling. Instruments and equipment for this purpose, such as konimeter, microscope, furnace, etc., were purchased, and a suitable office, equipped with laboratory facilities, was provided. The full time of the engineer is devoted to ventilation and dust control. On surface, in the mill crushing-plant and in the assay office and sample crushing room, an elaborate arrangement of hoods and exhaust systems has been installed to eliminate the dust. These installations, however, are not described in the present paper, which deals only with an extensive programme of underground ventilation as a method of coping with high dust concentrations, increasing temperatures and high humilities.

Jan 1, 1940

By M. O. Pekguleryuz, D. S. Aydin

The high temperature oxidation and ignition resistance of Mg-(0-6) wt% Nd alloys have been investigated via isothermal and continuous heating experiments conducted in air atmosphere. Alloy composition is observed to be effective in low levels (~ 0.5 %) in the ignition temperature (Ti) of the alloys; the Ti of pure Mg increased from 630 °C to 770 °C with 0.5 wt% Nd addition. However, no noteworthy improvement was achieved with further additions up to 6 wt% Nd. The initial microstructure was observed to determine the oxide structure on the surface due to the differing oxidation behavior of the phases (a-Mg + Mg12Nd intermetallics). It has been found that the formation of a Nd-depleted region at the subsurface due to extensive Nd oxidation at the oxide/intermetallic interface lowers the protective ability of the oxide scale.

Jan 1, 2015

Infrared spectroscopic data collected using HyloggerTM technology is being used to assess the mineral composition of Archean iron ore bedrock and Cenozoic detrital units in Western Australia’s Pilbara region. Analysis of infrared spectra enables quantification of: (1) composite iron mineralogy, (2) composite clay mineralogy, (3) hydrous silicates and (4) carbonate mineral abundances. Stratigraphic and rock mass unit logging of core has identified several detrital and bedrock units recognisable across the Pilbara. However, due to alteration related to mineralisation, weathering and later stage precipitate overprinting, it can often be difficult to assess the detrital-bedrock boundary and the occurrences of specific geotechnical units in the detritals and bedrock, particularly when using non-core drilling techniques and traditional geochemical assays. Infrared spectroscopic data collected concurrently on core from several sites has shown distinct correlation against existing unit subdivisions and associated geochemical parameters. Where infrared spectroscopic data have also been collected on rock chips recovered from reverse circulation infill drilling, these correlations allow robust geological and geotechnical models to be developed based on the typical mineralogical-geochemical signatures. The geotechnical sub-units identified in core can be readily distinguished using the various iron and clay minerals captured by the HyloggerTM technology as opposed to total iron, potassium, and alumina captured by geochemical assays. Further, some of the minerals targeted by infrared spectroscopic analysis (eg gibbsite, white mica, vitreous goethite) and their ubiquitous presence as the products of weathering, assist in recognition of various ancient weathering surfaces and help to define the origin of the material, whether bedrock or detrital. Overall, HyLogging of core and chips allows important mineralogy focussed data to be captured at minimal additional financial outlay. Correlations against geochemical unit identifiers are robust both within deposits and between deposits. Significant improvements in the confidence of geological and geotechnical models are attained.

Jan 1, 2015

By Fred W. Snow

THE mines of the Consolidated Copper and Sulphur Company, consisting of the Eust1s, the Albert, and the Capel mines, are situated w Ascot township, Quebec, about ten miles southeast of Sherbrooke, on the main line of the Quebec Central railway. Of these mines, only the Eustis is now producing, and it has been operated almost continuously for the past seventy years. Mining methods have been improved in recent years but are still old fashioned when compared with those employed in more modern and up-to-date mines. The ore is of milling grade and is mined for its copper and sulphur con-tent. Silver is present in small quantity, together with a trace of gold. The ore is mined by the shrinkage stope method. Pillars are frequently left as supports for the hanging-wall to prevent serious dilution of the ore and are sometimes recovered after the ore is drawn from the stope. Occasionally, small blacks of ore in close proximity to the shaft are mined by a cut-and-fill method. HISTORY ALBERT AND CAPEL MINES: The Albert and the Capel mines, originally known as the Capelton mine, were discovered in 1863 by George Capel (1). By the end of 1866 the Albert shaft had been sunk to a depth of 121 feet on an incline of about 30 degrees where a vein five feet thick was encountered. In 1879, these mines passed into the hands of G. H. Nichols and Company, by whom they were operated practically continuously until 1907. When mining operations ceased in that year, the shafts had reached depths on the incline of approximately 2,300 feet and 1,000 feet, respectively. These mines have been allowed to cave and fill with water and have been inaccessible for many years.

Jan 1, 1936

By A. L. Mackie

Arsenic is a highly toxic element and a known human carcinogen. It is often a contaminant in mine water discharges, particularly from gold mining and roasting operations, and has been found at concentrations as high as 4 g/L. Increasingly stringent controls on the concentration of arsenic allowed to be discharged into the environment cannot always be met by current treatment processes and thus enhanced technologies are required to achieve low treated effluent concentrations at reasonable costs. A novel two-step physicochemical treatment process was developed and tested at the bench-scale using synthetic mine water solutions (SMWs) in order to reduce arsenic concentrations in treated effluent to exceed current discharge regulations. The process includes chemical coagulation with ferric sulphate and ballasted flocculation for enhanced solid-liquid separation. The SMW contained 59 ± 2 mg/L arsenic with a slightly alkaline pH. The effect of arsenic speciation on the process was tested by using either arsenite, As(III), or arsenate, As(V), in the SMW solutions. Tests were performed at cold temperature (3 ± 1 °C) to ensure the process? efficacy year-round in northern climates. Arsenic in As(V) SMW solutions was removed to a final total concentration of 0.0054 ± 0.002 mg/L, almost half the current recommended allowable drinking water concentration of 0.010 mg/L. As(III) was removed to a concentration below the Metal Mining Effluent Regulations? (MMER) current limit of 0.50 mg/L, to 0.32 ± 0.06 mg/L, with double the coagulant dose used in Stage 1 for As(V) removal. Oxidant addition at a concentration of 5 mg KMnO4/L in Stage 2 resulted in final total arsenic concentrations of 0.017 ± 0.002 mg/L and pH adjustment with lime in Stage 2 resulted in 0.0415 ± 0.0007 mg As/L in treated As(III) SMW. Both of these modifications to the process reduced arsenic concentrations to below proposed new MMER limits (i.e., 0.10 mg/L). This two-stage treatment process was shown to reduce arsenic concentrations to well below current treatment guidelines while reducing or eliminating chemical oxidant demand.

Aug 1, 2013

By José L. Carvalho

"Time-dependent swelling deformation of several shaley rock formations in Ontario is a wellknown phenomenon. In shales and mudstones with a higher salt concentration in the pore fluid than the ambient fluid, the outward gradient generates an osmotic pressure which acts as the driving force for swelling. The swelling phenomenon appears to be related to ion exchange between the rock porewater and the surrounding water.The swelling potential is expressed as the percent swelling strain that occurs per log cycle of time, in either the vertical (perpendicular to bedding) or horizontal (parallel to bedding) directions. In addition, the swelling potential is also noted to be stress dependent. In practice, therefore, the conditions required for swelling are (i) the accessibility to water, and (ii) an outward salt concentration gradient from pore fluid of the rock to the ambient fluid. The relief of in-situ rock stress during excavation serves an initiating mechanism (Lo and Micic, 2010).INTRODUCTIONTime-dependent swelling deformation of several shaley rock formations in Ontario is a well-known phenomenon. In shales and mudstones with a higher salt concentration in the pore fluid than the ambient fluid, the outward gradient generates an osmotic pressure which acts as the driving force for swelling. Swelling is also controlled by the inter-particle bonding; if the bond strength exceeds the osmotic pressure, swelling will not occur, and vice-versa. The bond strength can be reflected by the calcite content which forms cementation bond between rock particles."

Jan 1, 2015

By D. G. Klaren, E. F. de Boer

Self-cleaning fluidized bed heat exchangers have demonstrated unparalleled performance internationally for the implementation of indirect heat transfer in severely fouling fluid environments. The ingenious configuration of recirculated cleaning particles through the tubes of vertical shell and tube heat exchangers provides the ability to solve any problems that arise as a consequence of tube-side fouling during indirect heat transfer to process fluids or slurries. In most cases, the cleaning particles consist of chopped metal wire, however other process-specific materials have been used. In addition to the mitigation of fouling effects, a number of other significant benefits for slurry heating are afforded by the mode of operation of the self-cleaning fluidized bed heat exchangers. Increased turbulence at the slurry/tube interface is imparted by the action of the fluidised particles, resulting in very high heat transfers at relatively low liquid velocities. Furthermore, given the thixotropic nature of most process slurries, the action of the fluidised particles imparts additional shear to the process slurry, resulting in shear thinning effects with a consequent reduction in pressure drop and enhancement of heat transfer across the heat exchanger. The benefits provided by the self-cleaning fluidized bed heat exchanger make it the ideal option for the indirect heating of laterite nickel slurry for High-Pressure-Acid-Leach (HPAL) plants. This article explains the principle and application of the self-cleaning fluidized bed heat exchanger technology for the processing of laterite nickel and cobalt slurries in HPAL plants. It also presents an elegant method to revamp existing direct heated laterite nickel and cobalt processing plants into an indirect heated configuration employing self-cleaning fluidized bed heat exchangers.

Jan 1, 2004

By Y. Huang

Corrosion of GaAs in aqueous electrolytes is a major limitation in implementing GaAs-based photoelectrochemical solar energy conversion systems, In this work, the corrosion behavior was investigated by electrochemical methods and surface analysis approaches, in both H2SO4 and NH3?H2O solutions, Open-circuit measurements showed that the cleaned GaAs surface was very sensitive to water/air, Impedance measurements for n-GaAs showed that an inductive loop only appeared at a high corrosion rate because a reaction intermediate is the oxidant for a further decomposition step in combination with chemical reaction with water, The results suggest that the same corrosion/decomposition mechanism occurred on n-GaAs in the two solutions, When the surface-hole concentration was low, the hole injection or generation process was the rate-determining step, At large reverse bias on n-GaAs, with high-hole concentration, the corrosion rate was limited by a Faradaic adsorption process, involving an adsorbed intermediate, The different surface compositions after corrosion in the two solutions can be explained by the dissolution of As(0), Further oxidation of As(0) to As(III) in NH3?H2O solution is still slow, as suggested from X-ray photoelectron spectroscopy (XPS) analysis,

Jan 1, 2005

By R. H. Knudsen

"In view of the chronic overcapacity problem in the world potash industry and Saskatchewan's recent emergence as a major producer, the long-term outlook for potash productive capacity and consumption is of importance and interest to both the Saskatchewan Government and the potash industry. This paper is based on a report recently published by the Saskatchewan Department of Mineral Resources on projected world potash productive capacity and consumption for the ten-year period 1970 to 1980. Potash productive capacity and consumption are estimated on a country and regional basis and projected annually to 1980. Tables and graphs are included which summarize projected capacity and consumption for the period and illustrate the impact of Saskatchewan's capacity upon the North American and world potash industries."

Jan 1, 1973

By E. Brzychczy

Artificial intelligence techniques are ever more frequently implemented in the modern world. One of their numerous uses is supporting enterprise management. Intelligent techniques and intelligent information technology (IT) systems can be implemented in mining-related issues as well. The author of this article concentrates on supporting the process of planning mining operations by intelligent systems and techniques. The author also underlines the importance of knowledge accumulation in a mining enterprise (especially tacit knowledge) as well as its efficient storing and using. Additionally, the author provides a short description of characteristics of intelligent IT systems and indicates their capabilities in planning mining operations. She presents two solutions, namely: an advisory system which supports the process of planning preliminary works and exploitation works in hard coal mines, and a method of modeling and optimizing mining operations. Finally, the author indicates a few possible future development trends of intelligent systems - the intelligent systems of decision support.

Aug 1, 2013

By Ju-hyung Ha

New automated curing system for mass concrete has been developed to improve the quality of concrete structure and to save construction time and cost. The principle of this system is the automated water circulation system of heated curing water. Applied curing water on the surface of mass concrete keeps the temperature difference between center and surface of the structure below the threshold of specification. Mock-up test and field application have been conducted to investigate the performance of this system. In the results, new automated curing system reduced the chance of thermal crack occurrence and improved quality of the concrete structure as well.

Aug 1, 2013

"Syncrude Canada Ltd. operates one of the largest surface mines in the world. The mining operation has two distinct phases: (1) the removal of the overburden, utilizing trucks and shovels; and (2) the mining of oilsand with drag lines and bucketwheels. Both phases combined move approximately 330 000 BCM per day.In support of current production demands and to provide a contingent oi/sand source, Syncrude has developed an Auxiliary Production System (APS) supported by the truck and shovel operation. This system utilizes oilsand sources within the existing mine area on an as-needed basis.The recent increased capabilities of the processing plant to handle a larger volume of oilsand has increased the reliance of the APS system. To facilitate the increased capacity, an auxiliary mine was developed external to the Base Mine operation with a production capacity of4.7 MBCM of oilsand per year.Development of the Northwest Auxiliary Pit began in January 1990, with the first cubic metre of oilsand taken to the plant in June, 1990. The Auxiliary Pit, as designed, has a total ore reserve of 68 MBCM of oi/sand."

Jan 1, 1993