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By H. Zhu, Q. Jiang

The leaching kinetics of iron during the atmospheric direct leaching (ADL) of marmatite concentrate was studied under the following conditions: reaction temperature of 343-383 K, slurry pressure of 0.3-0.7 MPa, particle size of (-74 ?m, +63 ?m), (-63 ?m, +44 ?m), (100%-44 ?m). The statistical effects of reaction temperature, total pressure and particle size of concentrate on the extraction and the leaching rate of iron were analyzed. The results show that reaction temperature is a significant factor while slurry pressure and particle size are not statistically meaningful with respect to the extraction or the leaching rate. The extraction of iron fits better to the mixed-controlled shrinking core model and the apparent activation energy was calculated to be 37.66 kJ/mol. The leaching of iron is mixed controlled by the interfacial chemical reaction and diffusion across the product layer.

Jan 1, 2014

By J. A. Abols, P. M. Grady

Recovery via gravity is one of the oldest mineral processing methods available. Unfortunately, the use of gravity techniques for gold recovery has been in decline for the past century as more effective chemical processes such as flotation and leach/CIP have been developed. Recently, with the push towards more sustainable environmental outcomes, the benefits of gravity separation have become more apparent. While gravity as a unit process is not usually capable of achieving as high a recovery as flotation or whole ore cyanidation, a combination of gravity devices alone or in conjunction with these processes can offer significant advantages to the operator. This paper reviews the range of gravity devices available, their application and the results that can be achieved by maximizing gravity through the use of a combination of gravity recovery devices. Three case studies are provided.

Jan 1, 2005

By H. D. B. Wilson

"IntroductionRECENT ADVANCES in geo-chemistry and in •our knowledge •of crystal structure provide a key which enables us to create a systematic picture of the genesis of many ore deposits. This genetic scheme may be used with confidence in assessing certain types of orebodies and may be of some aid in actual exploration, since it affords a rational explanation of the dependence of the composition •of the ore minerals on that of the rock type in which they occur with which they -are •associated. For purposes of the present paper, .the elements chosen are •chromium, vanadium, iron, and titanium. The oxides of all these metals occur in deposits of similar or related type, and it is proposed to show that, for each, the composition of the •ore mineral is related to •the composition of the enclosing :rock, and that one of the principal factors controlling the composition of the ore is the ionic size of its constituent elements.Geochemical PrinciplesThe crystals of the rock-forming silicates and of the magmatic oxide minerals are essentially ionic types. This means that they are composed •of oppositely charged ions such as Mg²+ and 0²-, which are held together by electrostatic attraction. The ions of each element are spherical, with characteristic size known as the ionic radius. Crystals are built up by the packing of these spheres in the most stable arrangement compatible with the size and the size and valence of the ions• involved.Many of the principles governing the formation of ionic crystals are •simple ,and logical."

Jan 1, 1953

By J. P. Harrison, R. Roostaei

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

Jan 1, 2015

By Claude A. Jr. Seger

Introduction This paper presents in detailed form the results of settling tests that were published in a few preliminary notes in the April 1949 issue of the Bulletin (p. 166). Carborel is the trade name for sodium carboxymethyl-cellulose and aluminium carboxymethyl-cellulose produced by the reaction of monochloroacetic acid on the alkali cellulose to form an ether. The water-soluble sodium carboxymethyl-cellulose has been known in Europe for several years as sodium cellulose glycolate and has been marketed under several trade names. These cellulose ethers, however, are relatively new in North America, where the name carboxymethyl-cellulose is often abbreviated to C.M.C., or they are referred to as cellulose gum. The particular grade of Carboxel used in the settling tests in the mill of Chesterville Mines, Limited, is the high-viscosity sodium carboxymethyl- cellulose known as Carboxel H.V. It is a white, fluffy powder and is hygroscopic, although not deliquescent. Carboxel solutions in water are colourless, odourless, and resistant to beat and light. They are stable to alkalies, but are precipitated by acids when the pH is reduced below 4.0, and also by solutions of soluble lead, iron, copper, aluminium, and chromium salts. Solutions of Carboxel exhibit the properties of hydrophilic colloids.

Jan 1, 1949

By M. A. Bérubé, M. Choquette, P. W. Godbehere

"RESUMELa scorie produite par le procédé pyrométallurgique d'extraction Noranda contient environ5% de cuivre. Elle est traitée comme un minerai conventionnel de cuivre au concentrateur de Mines Noranda et les rejets de flottation présentent encore des teneurs souvent supérieures à 0.3% en cuivre. La scorie est principalement constituée de magnétite, de fayalite et d'un verre siliceux. Bien sûr, Ie cuivre y est majoritairement sous forme de sulfures et d'un peu de cuivre métallique. Le verre contient toutefois un peu de cuivre en solution, de 0.14 à 0.33% en moyenne, selon l’echantillon examine, ce qui représente à peine 1% de tout Ie cuivre de la scorie. Dans les rejets de flottation, cela justifie par contre de 15 à 25% des pertes totales en cuivre, Ie reste se retrouvant sous forme de tres petits globules de sulfures de cuivre ou de cuivre métallique, en moyenne de 2 à 3 micromètres de diamètre et bien emprisonnes dans Ie verre.SUMMARYThe slag produced by the Noranda continuous smelting process usually contains about 5% copper. It is processed as a conventional copper ore at the concentrator of Noranda Mines. The flotation tailings still often contain more than 0.3% Cu. The slag is mainly constituted by magnetite, fayalite and a siliceous glass. Evidently, the copper occurs mostly as sulphides and, to a lesser extent, as metallic copper. However the glass contains a small amount of this metal in solution, between 0.14 and 0.33% on an average, depending upon the investigated sample. This represents scarcely 1% of the total copper in the crude slag, but as much as 15 to 25% of this metal in the flotation tailings, in which the major part of the copper occurs as very small globules of copper sulphides or metallic copper with an average diameter of about 2 to 3 um and well-locked in the glass."

Jan 1, 1987

"Ore deposits containing rare earth elements normally contain small amounts of the radioactive elements thorium (Th) and/or uranium (U). These are the naturally-occurring isotopes U238, U235, and Th232 (and associated decay-series daughter products) that are ubiquitous in nature, and that contribute a small percentage of the natural background radiation exposure encountered by humans. The presence of these radioactive materials in the ore deposit creates potential hazards to human health and the environment that must be dealt with properly in the mining, processing, and refining of the ores, as well as management of waste streams and residues. This paper presents an overview of the environmental and safety issues associated with U and Th, with particular emphasis on rare earth mining, processing, and refining projects; the regulatory approaches followed to ensure that rare earth deposits are developed, operated, closed, and decommissioned safely; and the development of information during the project predevelopment work and permitting processes that feed into the design, operation, and closure of tailings impoundments and milling/separation/refining facilities. Case studies will be presented subject to the availability of relevant public information. INTRODUCTIONNearly all ore deposits containing economically-recoverable rare earth minerals also contain small amounts of the radioactive isotopes for the elements thorium (Th) and/or uranium (U) and their associated radioactive decay products. Therefore, the handling and management of these materials in mining and mineral processing operations must be performed so that workers and the environment are protected from harm from Th and/or U (and their radioactive decay products), just as they must be protected from any other potentially harmful constituents present in the ore or introduced in processing. Examples of these might include ores with high sulfide content, which may pose a risk of acid rock drainage, or chemicals used in ore processing and metals production.The purpose of this paper is to present information on how rare earth mining and processing projects with ores containing Th and/or U can be developed, operated, and decommissioned safely according to applicable regulations intended to protect worker health & safety and the environment.It should be noted that some countries are considering developing Th as a feedstock for producing nuclear energy, which could have some effect on future development of rare earth ore deposits. To avoid confusion, that issue is not discussed in this paper."

Jan 1, 2012

By Earl Gebhardt

"The planning and design of mining panels in the Potash Corporation of Saskatchewan Inc., Lanigan Division mine Block B involved a number of investigative techniques. The techniques utilized to gain insight into the viability of mining included2-D and 3-D seismic surveys, longhole drilling, exploration wells, photo lineament, magnetic and gravity surveys, and actual room excavation.IntroductionPotash Corporation of Saskatchewan Inc. (PCS) owns and operates four potash mines in the province of Saskatchewan. The Lanigan Division mine is located 110 Ian east of Saskatoon, Saskatchewan, near the town of Lanigan.The Lanigan Mine commenced production in August 1968under the ownership or Alwinsal Potash of Canada Limited. The mine was purchased by PCS in 1977.Lanigan Division's productive capacity is 3.4 million tonnes of product per year. Ore is extracted from the "" B"" zone or Layer III or the Patience Lake member of the Prairie Evaporite, more than 1000m below surface . The Patience Lake member (approximately 20 m thick) consists of potash interbedded with salt. The average run-of-mine ore grade is 21070 K20 (Fig. I).The mine was initially developed using the room-and-pillar technique. Improvements in mining resulted in the use or extensible conveyors in long panel rooms."

Jan 1, 1993

By H. Sahay

"DISCLAIMER NOTICEThe views and conclusions contained in this presentation are those of the author and should not be interpreted as necessarily representing the official policies or recommendations of the Department of Mines and Energy, Government of Newfoundland and Labrador. ABSTRACTThis paper describes the main testing procedures that should be carried out to evaluate the capacity and capability of the service brakes on the large-size diesel-electric trucks now in common use at open-pit mining operations. Brake testing programs in general are described, and then consideration is given to different techniques of service brake testing, brake performance evaluation, braking energy and typical performance characteristics.IntroductionThe first diesel-electric truck with a capacity of about 85 tons was introduced in 1963 by Unit Rig and Equipment Company of Tulsa in cooperation with General Electric Company, who successfully developed and supplied the most important component- motorized wheels. Since then, its popularity and numbers have continued to grow, and now more than 3700 such units are in operation in mines around the world. In Canada alone, their number is more than 700, including about 150 in the Province of Newfoundland and Labrador. Similarly, their size has also grown from that initial capacity of 85 tons to 350 tons.Although the introduction of the electric trucks proved to be invariably economical, their indiscriminate use was not without severe consequences. Many runaways and even fatalities occurred when the dynamic retarder failed while the truck was travelling loaded down severe grades. The service brakes in such cases proved incapable of stopping runaway trucks, mainly due to their limited capability and the fading caused by excessive heat produced during the act of braking itself. This eventually led the various governments, the open-pit operators and the manufacturers to seriously question the braking capability as well as function of both service brakes and dynamic retarders. Extensive testing"

Jan 1, 1980

By James Logan

BC Alkaline CuBC Cu--Au PorphyriesAu Porphyries ?Formed over narrow time interval ~205 Ma ?from silica deficientvsalkali-enriched magmas ?At shallowdepths ?Structuralcontrol ?Cu-Au-Ag, trace Mo ?Oxidized system anhydrite, magnetite ?Multipleintrusions & multiplemineralized centres

May 1, 2006

By A. L. Craven, J. P. L. Bacharach, D. B. Stewart

"Inert gas use for underground mine fir e control is a well-established mature technology in some parts of the world. This paper reviews three candidate inert gases and describes three case histories where inert gas fire-fighting technology was used in actual underground fires.IntroductionInerting is the introduction of an inert gas into an atmosphere in contact with a fire to reduce the level of oxygen and hence the intensity of the fire 10 the point of extinction. The benefits of inerting include:a. Reduced Explosion HazardBy displacing oxygen from the atmosphere surrounding the fire the risk of secondary gas explosions is reduced. For example, simple methane-air mixtures at standard temperature and pressure are non-explosive below 12% oxygen. In actual mine fires, combustible gases may include hydrogen and carbon monoxide as well as methane. Such gases are also rendered non-explosive with oxygen removal to below 40/0. Fuel-rich oxygen-deficient mixtures can however be made explosive through dilution with air. Such dilution can occur downwind of the fire. It is also important to remember that the atmosphere in a sealed-off fire zone is rarely homogenous.b. Reduced Fire Intensity and SpreadIn a fire zone the initial combustion may well set alight materials surrounding the fire. Inerting can reduce the intensity and spread of secondary combustion and can cool the area surrounding the fire zone after the fire itself has been extinguished.c. Reduced Air LeakageLeakage of air into sealed areas in excess of the natural leakage may be reduced either by introducing inert gas into the leakage paths to replace air or by pressure balancing seals and providing a chamber of nitrogen on the outbye side of the seals. Both methods assist in the reduction of the intensity of combustion and hasten oxygen starvation."

Jan 1, 1986

By R. A. May, P. J. Brooks, W. M. Smith

"Neill and Gunter Limited (NGL) has prepared a preliminary design and a cost estimate for a ferric chloride leach plant to recover copper, lead, zinc, and silver from a typical complex sulphide ore. This plant design is specifically intended to treat unconcentrated ground ore (flotation feed), but can be readily adapted to treat bulk concentrates. Samples of ground ore and bulk concentrate were obtained from Heath Steele Mines, Miramichi, New Brunswick, laboratory testing, and preliminary process flow sheet preparation was carried out by the Research and Productivity Council in Fredericton, New Brunswick. Approximately thirty drawings have been produced, including process and equipment flowsheets, process piping and instrumentation drawings, and preliminary general arrangements. Preliminary capital and operating cost estimates were prepared for a plant that would treat 1000 t/d of crushed and ground ore to produce about 30 000 tpy of zinc. Capital and operating cost estimates were also projected for plants up to 4000 t/d of processed ore. Recoveries of 99% for zinc, 98% for lead, and 96% for copper were achieved in laboratory tests on unconcentrated ore. These recoveries were higher than the overall recoveries obtained from bulk concentrate, yielding approximately 10% more revenue.A 1000 tonne per day plant was determined to have a low return on investment, however, depending on the size and type of mining operations employed and the FCL plant throughput. DCF-ROI projections of 20% to over 30% were calculated for 100% equity financed “green field” mine, mill and FCL plant operations of 2000 t/d and higher"

Jan 1, 1997

By B. Szpunar

Structural and mechanical changes of urania are investigated when oxidized to U3O8. The CASTEP ab-initio quantum mechanical program, employing density functional theory is used. The total energy technique is implemented to investigate changes in the lattice constants. The ab-initio calculations predict a 36% increase in the volume per uranium atom when transforming from UO2 to U3O8, which agrees very well with experimental data. The implication of this prediction on the linear expansion and fuel fragmentation is discussed. The calculated elastic constants of urania are in good agreement with experiment. The predicted mechanical properties of UO2 and U3O8 are compared.

Aug 1, 2010

By J. G. Conaway, P. G. Killeen

"Gamma-ray spectral logging, a useful technique for uranium exploration and evaluation, has generally been underutilized by the Canadian mining industry. Provided that the technique is properly applied, it is capable of yielding reliable quantitative information regarding the distribution of uranium and other radioelements along the borehole under most conditions.In practice. there are numerous factors which potentially can degrade the quality of the log and thus any quantitative interpretation based on it. Fortunately, the appropriate choice of logging equipment and technique can avoid many such problems, and corrections can be applied to the data to compensate for most of the others."

Jan 1, 1980

The integration of mining and mineral processing technologies into new advanced mining systems is considered to offer several benefits, including selective mining, reduction in waste, increased productivity, flexibility, and improved resource utilization. This paper focuses on underground hardrock mining and the integration of pre-concentration technologies into future mining systems as representing realistic, shorter-term integration options. Control of fragmentation to optimize grinding, pre-concentration of ores, in situ leaching, and modular mining/mineral processing systems are possible with existing technology. Current research is directed toward development of integrated underground systems that minimize surface activity and minimize or eliminate surface waste disposal. Results from a simulation model of an integrated underground pre-concentration system are presented.

Jan 1, 2002

By G. K. Livingstone

"This paper describes mining conditions in the Kaiser surface and underground coal mines in the Sparwood area of southeastern British Columbia. Mining methods are explained, major mining equipment is listed and production rates are given. Reclamation methods and results are described. Data are given on safety organization, safety practices, accident statistics, safety inspections and absenteeism. IntroductionThe coal mines of Kaiser Resources Ltd. are located in the southeast corner of British Columbia. All present mining is in the Sparwood area, where operations began in 1900 with the opening of the Michel underground mines. Production increased rapidly at first, then went through successive periods of depression and prosperity. Following are the highlights. Quantities are in clean, short tons. 1900 1910-Rapid rise in production to a peak of 512,000 tons in 1910.1911-1924-Reduced rate of production, averaging 238,000 tons per year, due to strikes, manpower shortage during World War 1 and post-war depression.1925-1929-Second prosperous era, with production climbing to 383,000 in 1929.1930-1933-Second depression-production falling to 231,000 in 1933.1934-1942-Third era of prosperity-production recovered and new production peak of 908,000 tons reached in 1942 during World War II.1943-1956-Corttinued prosperity, with production averaging 720,000 tons per year.1957-1959-Loss of markets to oil and gas; production dropping to 517,000 tons in 1959.1959-1969-Recovery due to new coal market in Japan; production climbing back to the 900,000-ton level.197D-Present-Jump in production reaching 6.6 million tons in 1975. This was the result of the purchase of the property by Kaiser Steel, who negotiated a large-volume, long-term contract with Japan, built the coal port of Westshore, reduced shipping costs by instituting unit trains, and reduced production costs by investing in large-scale mining machinery and a new preparation plant."

Jan 1, 1980

By P. Clinton Milne

Uranium mines in Washington State include the producing Midnite and Sherwood mines and several mined-out deposits, the most productive of which was the Daybreak mine. The Midnite mine is generally classified as a hydrothermal deposit consisting of tabular orebodies in Precambrian pelitic and calcareous metasedimentary host rocks. The host rocks occur as roof pendants in a Cretaceous porphyritic quartz monzonite intrusive; the quartz monzonite averages 12 ppm U308 The uranium deposit appears to have undergone a complex genesis, involving a series of depositional and enrichment stages. The Sherwood uranium deposit, approximately 4 miles south of the Midnite mine, occurs near the bottom of a basal Late Cretaceous to Paleocene arkosic conglomerate. The conglomerate lies nonconformably on the porphyritic quartz monzonite that is associated with the Midnite deposit. The Sherwood and Midnite uranium deposits may have had a similar genetic history linked by a common uraniferous pluton source, ground-water action, and/or leaching of uranium-rich ash flows from now-eroded, overlying, Eocene volcanics. The Daybreak deposit, in northeastern Spokane County, consists entirely of secondary uranium mineralization (metaautunite) in a quartz monzonite pluton. Mineralization is confined to a low-angle fault zone and is most highly concentrated at the intersection of primary and secondary shears. Both hydrothermal and ground-water origins are feasible. Besides the Midnite-Sherwood area, 14 other areas in the western Okanogan Highlands physiographic province and Cascades region have favourable characteristics for uranium potential. Criteria include the existence of uranium occurrences, Tertiary basin sediments with intercalated volcanic and volcaniclastic rocks, favourable geochemical data, alkaline plutons associated with uranium occurrences or borders of Tertiary basins, and structural controls.

Jan 1, 1979

By R. Q. Honaker

A significant problem in ultrafine particle classification is the significant amount of submicron particle by-pass to the coarse particle stream. In classifying cyclones, submicron particle by-pass to the underflow stream can be reduced by decreasing water recovery. Past studies have shown that a reduction can be realized when the feed solids concentration is increased or the apex diameter is reduced. However, both adjustments tend to increase the particle size cut point and negatively affect classification efficiency due to the impact on slurry rheology. The addition of a viscosity modifier to the feed stream of a classifying cyclone improved the classification performance and decreased the particle size cut point over a range of feed solids concentrations. The detailed test program investigated the use of the modifier in conjunction with varying apex diameters to identify conditions that minimize ultrafine by-pass. With small apex sizes, roping conditions were readily eliminated by the addition of viscosity modifiers. The addition of the modifier had no deleterious effect on froth flotation performance, which commonly serves as a downstream separation process. The fundamental and practical benefits of viscosity modifiers in classification processes are discussed in this publication.

Jan 1, 2006

By C. Klinkenberg, G. Zhu, K. Hulka, S. V. Subramanian

A quantitative model based on strain accumulation in multi-pass rolling is developed to overcome a large critical strain for dynamic recrystallisation in a Nb microalloyed steel with high Mn content (HTP steel). The larger the critical strain for dynamic recrystallisation, the finer is the dynamically recrystallised grain size. The initial mill trial showed that it is feasible to achieve ultra-fine grain size by dynamic recrystallisation but the prevention of static recrystallisation in between passes is identified as an essential condition to suppress mixed grain size. The data-base on static softening kinetics at short interpass time was experimentally determined on WUMSI and incorporated in the model. The model is used to optimise the strip rolling schedule to prevent static recrystallisation in the interpass time. The rolling simulation of strip rolling schedule has validated the model prediction that it is possible to obtain a uniform ultra-fine ferrite grain size of about 1-2 micrometer diameter in final ferrite microstructure for industrial rolling parameters. A user friendly software package has been developed to apply the model for off-line control of mill processing parameters, i.e., time-temperature-deformation schedule of finish rolling in order to accumulate large strain to overcome a large critical strain for dynamic recrystallisation. The model is a powerful predictive tool for grain size control in multi-pass rolling.

Jan 1, 2004

By D. Weston

"IntroductionIn preserving this paper, the author would like to acknowledge the basic development work carried out by the Consolidated Mining & Smelting Company of Canada, without whose initiative the development of the Aerofoll mill would not have been possible. In particular, he would like to pay tribute to the late Mr. C. T. Oughtred, Superintendent of Concentration for Cominco, whose vision and research-mindedness was the chief contributing factor in the carrying alo.ng of the original development.He would like also to acknowledge the help and co-operation of the staff of the Mines Branch, Department of Mines and Technical Surveys, Ottawa, without which the finalization of the un.it and its application would have been many additional years in coming to industry; and the assistance and encouragement given so freely by Mr. C. W. Dowsett, Consulting Metallurgical Engineer, Ventures Limited, and Professor A. M. Gaudin, Massachusetts Institute of Technology."

Jan 1, 1950