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By M. Soderstrom

In a solvent extraction (SX) plant, stage efficiency calculations are used to determine mixer efficiency. With modern extractants and mixing equipment, it is generally taken for granted that stage efficiencies will be above 95%, but this is not always the case. Dependant on mixer/solution conditions, stage efficiencies can occasionally be low, therefore leading to higher reagent usage. Proper methods to identify when stage efficiency performance is below expectations, and ways to identify if it is an equipment or chemical issue are valuable tools for a plant metallurgist. With these tools and skills an on-site metallurgist can more quickly return their SX plant to proper operation. This paper will discuss methods for analyzing stage efficiency, evaluating factors that may affect stage efficiency, and evaluating the impact of stage efficiency on the overall operation.

Jan 1, 2010

By Antti Roine

HSC Chemistry is a widely-used therniochemical tool in the chemical and metallurgical industries and in universities. The main reasons for it's popularity is the easy user interface and the large integrated thermochemical database. This paper summarizes the main properties of the new HSC Chemistry version 3.0, and gives a short review of the new features: Some metallurgical applications with the new features are also presented. HSC Chemistry 3:0 contains seven calculation modules and a thermochemical database with more than 11 ,000 chemical compounds. The new spreadsheet type table editor gives more control to the user, the new graphics routines have fewer limitations and more formatting properties. The capability and speed of calculation routines have also been improved.

Jan 1, 1998

By Q. Dai

In order to float coarse sylvite particles, Potash Corporation of Saskatchewan Inc. (PCS) uses amines and extender oil (Esso 904 oil). Since the content of polycyclic aromatic (PCA) compounds in Esso 904 oil is high, PCS has sought a suitable replacement. Various types of physicochemical tests, including measurements of the electrokinetic potential of emulsified oil droplets, oil/water interfacial tension and wetting of KCl plates by oil, did not provide conclusive results. However, captive bubble contact angle measurements on KCl plates in brine in the presence of flotation agents correlated reasonably with the flotation response. A few non-toxic oils were found to provide good results in the flotation experiments and are now tested under industrial conditions.

Jan 1, 1992

By J. D. Aitken

"DEFINITION OF THE REGIONTHE REGION considered in this paper is bounded on the south by the 60th parallel, on the north by the Beau-fort Sea and Amundsen Gulf, on the east by Archean rocks or by highly deformed Proterozoic rocks of the Canadian Shield (certain weakly deformed Proterozoic strata being regarded as belonging to the Great Plains), and on the west mainly by the Mackenzie and Richardson Mountains.Only the unmetamorphosed strata of the region are considered; that is, the geology of the crystalline basement is ignored.SIGNIFICANCE OF THE REGIONThe region is significant from three points of view -namely, the economic, the scientific and the social. It constitutes 46 per cent of the area of the Western Canada Sedimentary Basin."

Jan 1, 1970

By Hitch M.

Many mining wastes, especially those from the metal mining industry, have traditionally been treated as a matter of little or no value and in practice a cost burden. Some wastes, due to their reactivity characteristics, have emergent values that go beyond purely economic and into the environmentally beneficial realm. This paper discusses the changing paradigm of mine waste management. Such fundamental parameters such as cut off grade, and strip ratio, are positively impacted by the revaluation of waste rock material. Mine rock waste can now be seen as a commodity of value, similar to the underlying ore being mined and influences the economic performance of suitable projects. This valuable material can be used for industrial purposes including acid neutralization as well as the capture and long-term disposal of anthropogenic carbon dioxide. The Turnagain Nickel project, located in northern British Columbia serves as an example of how waste rock material can become an important matrix for carbon capture and sequestration and can benefit economically from it. By producing material that has emergent economic value as well as carbon capture and sequestration capabilities, the sequestration matrix producer is a beneficiary of new carbon credits that have a market value and is looked upon favourably by regulatory authorities and affected stakeholders.

Jan 1, 2010

By I. Gombköto

To sustain the growth of industrial production necessitates the increasing of the amount of processed mined raw and secondary materials. As a side effect of raw material production, the amount of tailings material, - coming from mineral processing operations ? increases as well. Using wet technology, these tailing materials are generally transported and stored with the water used for previous operations. This habit could lead to dangerous situations. Enough to remember the disasters had happened to the last decade, safe tailings operations need to remove as much water from the solid as possible. Environmental, technical and economical needs should meet, therefore using a technology combining these specific needs could be necessary. Paste technology was introduced generally into tailings operations at the last ten years, as an answer to the call of the above mentioned challenges, however there are still many questions to answer within the frame of using it. The Institute of Raw Materials Processing and Environmental Process Engineering of the University of Miskolc has been dealing with mechanical process engineering, especially by the support of the EU project TAILSAFE Contract nº EVG1-CT-2002-0066 and the NKFP 3A/068/2004 Hungarian fund extensive research has been carried out about paste technology. Different test methods and materials were applied. Tested tailings materials were as follows: different fly ashes from coal power plants from Pécs ? Hungary, Gyöngyös ? Hungary, Neyvil ? India, different Croatian ashes, hazardous waste incineration plant ashes from Dorog ? Hungary, different kind of sands from Hungary, fine glass sand from Fehérvárcsúrgó ? Hungary, flotation ore processing tailing from Gyöngyösoroszi ? Hungary. Different additives, as gypsum, bentonite and cement were tested as well. The applied test methods were as follows: physical material testing (laser sizer, piknometer, different microscopes), X-ray diffraction analysis, settling columns, the three measuring pipes tube viscometer (16~27 mm pipe diameter), a hydraulic test loop with different pumps (40~53 mm pipe diameter, 0.2~4 m/s average slurry velocity range, 0%~52 % volumetric concentration range), rotational viscometer, Cassagrande yield locus tester and the slump cone test. This paper summarizes and systematizes the results of the aforementioned research as well as reports about the developed paste pipe transport design method based on the fine suspension ? coarse mixture model. The paper also reports about a systematic experimental series with different materials to establish criteria when high concentration suspensions behave like paste.

Jan 1, 2014

By E. R. Mitchell

When we grow up in an urban environment and choose to become a part of a way of life, it is sometimes difficult to appreciate the cost of this decision in terms of pollution. Explained in this article is our dependence on technology and the amount of pollution that technology produces. Inventories of air pollution on both a personal and a national basis are given so that the reader may judge the magnitude of the problem. In doing so, it is hoped that the reader will understand the need for a responsible attitude toward pollution by everyone and how he can make a personal contribution.

Jan 1, 1971

By W. W. Adams

"A recent paper prepared by the writer summarized the results of an analysis of the accident records of 34 metal mines for the calendar year 1925. The present paper summarizes the results of a similar analysis of the accident records of 59 coal mines for the same year. This summary is based upon reports furnished to the Bureau of Mines, Department of Commerce, by operating companies that par¬ticipated in the National Safety Competition of 1925.The purpose of the Competition was to establish the lowest accident-severity rate, thus showing the smallest loss of time from accidents in proportion to total number of man-hours worked. The reports covered all lost-time accidents that occurred during the year, that is, all accidents that disabled an employee beyond the day or shift on which the accident occurred. Detailed information for each of the 59 coal mines is given in the appended table. Each mine employed at least fifty men underground; over half of than employed more than 200 men underground. Hence the accident records should be typical of those of large-scale mining operations in general where the company is devoting special attention to accident-prevention work. The mines covered by the reports are situated in eleven States: Alabama, Illinois, Indiana, Kentucky, Maryland, Ohio, Pennsylvania, Tennessee, Utah, Washington, and West Virginia.A tabulation of the reports covering the 59 mines showed an accident-frequency rate of 123 per million hours of ""exposure* and an accident-severity rate of 10.214 per thousand hours of exposure3. The total volume of exposure or employment was 29,117,561 hours, representing the equivalent of work of 12,000 men for three hundred 8-hour shifts. The records covered employment and accident above ground as well as underground, although they did not include stripping or open-pit mining. Accidents during the year resulted in 33 deaths, 1 permanent total disability, 28 permanent partial disabilities, and 3,510 temporary injuries. These accidents represented a loss of tine equal to 297,417 man days. In arriving at this lost-time equivalent, each fatality and permanent total disability was weighted at 6,000 lost days (see footnote 3), as specified in the scale adopted by the International Association of Industrial Accident Boards and Commissions; permanent partial disabilities were weighted according to nature of injury, in accordance with the scale adopted by the :Board; temporary injuries were weighted according to the actual number of calendar days during which the employee was incapacitated as a result of the injury."

Nov 1, 1926

By J. B. De Hart

In the September issue of the Bulletin, 1923, there is a paper by J. A. H. Church on "The Spontaneous Combustion of Coal in Mines", which is more or less a general discussion of the subject. Mr. Church gives a list of mine fires which have occurred in Alberta. Of the total of thirteen fires, six are attributed to spontaneous combustion. Of these six fires, it will be noted that five are in thick pitching seams. These fires occurred in the following mines during the years shown, at Frank in 1909; at Lovett in 1916; at Cadomin in 1920; at Yellowhead in 1922, and at Cadomin in 1923. Every one of these fires has occurred, as Mr. Church points out, in a seam of over 12 feet in thickness, and furthermore not one of these fires has been extinguished, although in every case large sums of money were expended and considerable risks . taken in fire fighting. Now it is quite evident from these facts that mines working seams of this nature are faced with a very grave danger and it behooves us to study the matter and endeavor to arrive at some practical method of preventing the loss of our coal mines from this cause.

Jan 1, 1924

By T. J. Ballard

The Tallapoosa Copper mine in Haralson County, Ga., has been operated, or under development at various times since before the Civil War. The geology of the deposit is similar to that of many of the pyrite deposits occurring in the belt of ancient crystalline and metamorphic rocks that extends diagonally northeast-southwest across the State. The Bureau of Mines, in its program of investigation of, strategic mineral deposits, diamond-drilled four holes totaling 1,570.3 feet at the deposit during the period June to September 1947 to verify the old drill records and the continuation of the deposit at depth.

Jan 1, 1948

By S. A. Bunk, E. C. Eccleston, J. J. Amsden

Fluidized bed technology has been widely applied to mineral and metallurgical processes. Over the years, modeling of fluidization technology has progressed to a level at which basic design parameters can usually be defined based on empirical correlations. In addition, scale-up considerations have become better understood, and significant advances have been made in the area of computer simulation. Despite these advances, fluidization is a complex phenomenon, and modeling tools remain limited in their ability to simultaneously model both fluidization and chemical process parameters. As a result, almost all mineral and metallurgical applications of fluidized bed technology require pilot testing prior commercial scale design. This paper outlines pilot plant testing requirements and process development considerations for development of low technical risk commercial designs.

Jan 1, 2011

By W. Hardtke, B. Perry

Model reconciliation problems at the low-grade, high-nugget Phoenix gold-copper deposit led to an examination of the influence of production decisions on ore-waste classification. A conditional simulation study of the deposit was used as the basis for: 1) quantification of dilution at different bench heights, 2) quantification of ore-waste misclassification relative to bench heights and cut-off wades, and 3) determination of an appropriate number of samples to optimize ore-control polygon definition. Actual reconciliation data were empirically used to support conclusions. Simulations of both gold and copper were combined through net revenue modelling. These simulations increased understanding of the nature of the deposit and provided insight for resource modeling and mine planning.

Jan 1, 2011

By Thomas Glück

Established and emerging mining companies face significant challenges in managing their operations and projects. Outcomes often do not meet the expectations of all the stakeholders of particular developments. This paper reviews typical management practises used by mining companies to undertake mining projects and improve their operations. A simple application of the House of Quality (HOQ) tool used in the Quality Functional Deployment (QFD) management approach is presented. It is shown that a QFDMMPtg approach could lead to innovation in mining processing plant development practice.

Jan 1, 2015

By Kenneth L. Rubow, Virgil A. Marple, Zhigun Zhang

"A theoretical technique has been developed and verified experimentally for determining the aerodynamic diameter of irregular shaped particles. The aerodynamic diameter of a particle is a very important parameter for determining where that particle deposits in the respiratory tract. Many instruments, such as impactors and cyclones, will determine the aerodynamic size distributions of aerosol particles but few analyze the particles individually. The theoretical approach of our technique is to solve, by use of high speed computers, the three-dimensional Navier-Stokes equations to obtain the flow field around an irregular shaped particle of any contour. The computer program will then determine the drag on the particle, and thus the aerodynamic diameter of the particle can be calculated. The experimental approach has been to pass the particles through a centrifuge and collect the particles upon a collection foil. The position of a particle on the foil is an indication of its aerodynamic diameter. These particles were then shadowed in two orthogonal directions and inspected under an scanning electron microscope (SEM). The top view of the particle in the SEM plus the views of the two orthogonal shadows allows one to determine the three-dimensional shape of the particle. Studies have been performed on silica, coal and talc particles with aerodynamic diameters in the 1 to 4 µm size range. The three-dimensional shape, as is determined from SEM analysis, was used in the theoretical computer program and the results compared. It was found that in most cases the agreement between the experimentally and theoretically determined aerodynamic diameters was within 5%. INTRODCJCTIONThe equivalent aerodynamic diameter (EAD) of a particle, defined as the diameter of a unit density sphere with the same falling speed as the particle in question, is an important size measurement of the particle. This is especially true when attempting to predict where particles may deposit in the respirator tract. Therefore, EAD is an important parameter when considering respiratory diseases caused by particles, such as coal workers pneumoconiosis (CWP).Many instruments will measure the EAD size distribution of the aerosol particles, but few analyze the particles individually. Impactors, cyclones and virtual impactors normally collect particles upon substrates or filters which are · then analyzed gravimetrically to determine the mass concentration of the particles in that size classification. The EAD of particles can be measured on an individual basis with centrifuges, inertial spectrometers and the TSI Aerodynamic Particle Sizer (APS). Centrifuges are most ideally applicable for studying individual particles as the particles are deposited, on long removable foils, at locations dependent upon their EAD."

Jan 1, 1990

By C. A. Komar

Renewed interest in the underground gasification of coal evolves from comprehensive studies of earth fracture systems that indicate that the movement of fluids can be controlled in the coalbed. In particular, directional property studies of natural microfissure occurrence, permeability, ultrasonic velocity, tensile strength, and orientation of intervals of inherent rock weakness, together with geologic structure setting and fracture trace analysis, can predict the gaseous flow paths in the coalbed. Having this information, the dominant direction in which gases generated and/or liberated by heat would move can be determined so that appropriate well patterns can be developed. Together with advances made in drilling technology that permit long horizontal holes to be drilled through the coal seams, tests can be conducted to determine whether directional control will permit devolatilization of the coalbed and gasification of the remaining hot coke in a systematic manner to produce a low-Btu gas suited for the generation of electricity.

Jan 1, 1973

By J. T. McGrath, R C. A Thruston

The structural changes which take place in polycrystalline copper under the action of alternating cycles of torsion stress were studied, using the optical microscope and the X-ray dif-fraction camera, and an attempt was made to correlate them with changes in the shape of the cyclic stress-strain curve. It was found that the period of work-hardening was less than one per cent of the fatigue life, and that persistent surface marking, which are assumed to be incipient or actual microcracks, occur upon completion of work-hardening. X-ray diffraction patterns revealed considerable grain distortion at the completion of work-hardening in specimens cycled at a high strain amplitude. This distortion became progressively less as the strain amplitude de-creased. Mechanisms for the completion of work-hardening and the formation of microcracks are discussed.

Jan 1, 1962

By J. E. Gill

Discovered in 1952, the deposits have been explored by diamond drilling on and near a group of islands in lake Nipissing and from under-ground workings. The ore mineral is a uranian pyrochlore. It occurs in breccia zones in association with calcite, apatite, a?cmite, feldsiiars, biotite, magnetite, sulphides, and fluorite in varying amounts. The pyrochlore concentrations occur in a steeply-dipping gneiss series with some crystalline limestone. Trends indicate a ring structure 114 miles in diameter. The main ore zone shows evidence of repeated brecciation and a succession of replacements .giving rise to a complex of rock types. Pegmatite and lamprophyre dykes cut the ore as do calcite-fluorite veins and later faults with small displacements. Columbium and uranium occur al-most exclusively in pyrochlore, but the proportions vary. There is no tantalum and only small amounts of titanium.

Jan 1, 1957

By William E. Wallace, S. J. Page, B. L. Razzaboni, C. A. Hill, Pamela Mike, P. Bolsaitis, M. J. Keane, Val Vallyathan

"Respirable quartz cytotoxicity, as measured by erythrocyte hemolysis and pulmonary macrophage release of lactate dehydrogenase in vitro, is neutralized by boiling in water in glass test tubes for 10 to 40 minutes. The cytotoxicity is reduced to near zero by boiling l to IO mg quartz per milliliter water. For greater concentrations of quartz in water the hemolytic potential after 40 minutes of boiling approaches that of native quartz. Replacing the medium with fresh water midway through boiling results in full detoxification through 20 mg quartz per milliliter water. Pre-boiling the medium with silica reduces the detoxification effect. Detoxification persists after mild drying at l 10°C for 8 hours, and persists after three days of resuspension in water at room temperature.INTRODCJCTIONResearch underway to determine interactions of quartz and other mineral dust surfaces with pulmonary fluids and alveolar macrophages in culture led to the observation that when dusts were autoclaved in aqueous suspension, their cytotoxic effects on macrophages were suppressed, in some cases fully and even after several days incubation with the cells. This finding was in direct contradiction to earlier results from both short term macrophage lysosmal enzyme release assays, as well as longer term cytotoxicity assays from macrophages in culture; in those studies, dusts were steam autoclaved at 121°C with no liquid water but with steam present. 1.2 However detoxification under boiling conditions has been reported in other research. 3 It was decided to use the hemolysis assay to further investigate these findings, because of its sensitivity simplicity and cost.RESCULTS AND DISCCISSIONRespirable quartz dust used in this study was taken from a stock of crystalline silica, Min-U-Sil; obtained from Pennsylvania Sand Glass Corporation, fractionated in air with a particle classifier. The small size fraction retained for use was 80% less than S micrometer particle diameter, with an area equivalent median diameter of 1.24 micrometers as estimated by automated image analysis. The silica was at least 98.S mass percent silica as determined by X-ray energy spectrometric analysis; and the crystalline form was alpha-quartz as determined by X-ray diffraction. It's specific surface area was 3.97 square meters per gram as determined by nitrogen adsorption isotherm methods. I"

Jan 1, 1990

By J. K. Atherton

If the metals sector is to contribute successfully to sustainable consumption we must adopt principles and practices which address the entire life cycle of the materials we produce. Progress must be founded on a sense of shared responsibility for the resources we utilize and the materials we create - it is this integrated approach which lies at the heart of materials stewardship. Materials stewardship means mining and metals companies producing materials in a responsible manner and then working with others, beyond their site, to ensure that the downstream material flows and applications are managed properly to create maximum societal value. In September 2006 ICMM published 'Maximizing Value: Guidance on implementing materials stewardship in the minerals and metals value chain'. This document takes a practical view presenting structured guidance as well as good practice case studies. In the publication, materials stewardship is described in terms of the range of activities that can be undertaken to ensure that all parties work collectively toward the responsible use of metal and mineral resources. This paper introduces the materials stewardship concept as set out in `Maximizing Value' and describes the business case for implementation as well as the ICMM framework for promoting materials stewardship.

Jan 1, 2007

By W. A. Bell

The Carboniferous system of rocks in the Maritime Provinces include as workable mineral and organic substances, gypsum, anhydrite, salt, coal, building stones, grindstones, limestones, brick-clay shales, fire-clay shales, oil shales, etc. The system is, therefore, pre-eminently of economic value to the provinces in which it occurs, and the more knowledge we may gain concerning it, the more we may be prepared to aid in the development of these useful substances. For this purpose it is not sufficient to state that the ground upon which we stand is underlain by Carboniferous rocks. In-discriminate digging or drilling will not open many new mines of wealth, however difficult it may be to dampen the optimism of gamblers. For mineral wealth has not been scattered in the rocks haphazard, now here, now there, but its distribution has been the result of natural earth forces acting at intervals throughout the countless millions of years that have elapsed since our planet was born. As regards the majority of metalliferous deposits, the earth forces involved have resulted in the penetration of surface or sub-surface rocks by molten rock-matter and associated mineral solutions from deep-seated sources. But the economic Carboniferous deposits that have been mentioned are themselves types of bedded surface rocks rather than immigrant deposits, and their formation and geological history is closely related to that of the rocks with which they are interbedded.

Jan 1, 1924