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By H. E. Rowen

As high grade iron ore deposits dwindle and costs rise, sintering becomes more and more important. The steel industry is now faced with beneficiation problems once peculiar to nonferrous work. Succeeding articles describe recent advances in this field. Here is presented the first chapter of a history still being written. SINTERING, for the purpose of this discussion, is defined as the art of burning a solid fuel with 90 to 95 pct ash content. Considering problems of combustion involved in keeping a home furnace burning properly with 12 to 20 pct ash in the fuel, it is evident that combustion represented by the definition has to be right or nothing is going to happen. Our forefathers discovered that many ores containing metals essential to the steadily rising standards of living were associated with elements such as sulfur and arsenic, which had to be removed before refining. This they did by utilizing the solid fuels they had available-the sulfur or other readily combustible components-to create roasting heat. One of the early methods is demonstrated in an old woodcut of the roast heap, Fig. 2. Ore was broken into chunks, piled on an ignition layer of solid fuel-logs in this case-and then. ignited. The sulfide ores roasted as the sulfur burned out. As shown in the background, the countryside was rapidly denuded of all vegetation by the great quantities of SO2 and other liberated gases.

Jan 1, 1961

By M. D. Attfield

During 1992 a number of papers were published on aspects of respiratory disease in US underground coal miners. These included reports on trends in prevalence of coal workers' pneumoconiosis, the risks of developing coal workers' pneumoconiosis in relation to dust exposure, and the relationship between lung disease other than pneumoconiosis and dust exposure. The intent of this paper is to provide a summary of the essential findings from these investigations. PREVALENCE AND INCIDENCE OF COAL WORKERS' PNEUMOCONIOSIS Coal workers' pneumoconiosis (CWP) is usually detected in living miners through use of the chest x-ray. Deposits of dust in the lung, and the fibrotic tissue reactions to the dust, are manifested on the x-ray as small and large opacities. These abnormalities are quantified into degrees of severity using a standardized classification scheme (the International Classification of Radiographs of the Pneumoconioses of the International Labour Office). For small opacities, the scheme provides for a four-point scale of abnormality (0, 1, 2, 3), reflecting increasing profusion of the opacities on the x-ray. In this report, category 1 or greater small rounded opacities (CWP 1+) represents the earlier radiographic stages of pneumoconiosis. Large opacities, indicate the later and often disabling stage of pneumoconiosis, usually referred to as progressive massive fibrosis (PMF). Information collected in a national surveillance program for underground coal miners (the Coalworkers' X-ray Surveillance Program (CWXSP)) and a large epidemiologic study (National Study of Coalworkers' Pneumoconiosis (NSCWP)) provide a means to assess trends in CWP prevalence over the years following the reduction in dust levels mandated by the 1969 Federal Coal Mine Health and Safety Act (FCMHSA). These programs are operated by the National Institute for Occupational Safety and Health (NIOSH), and are described in detail in Attfield and Althouse (1992) and Attfield and Castellan (1992). Both studies were divided administratively into distinct time periods, and the results shown here reflect that division. Figure 1 shows the prevalence of CWP 1+ as determined from data from the CWXSP, plotted by time period and years in mining. There is evidence of a temporal reduction in prevalence. (The lack of an obvious decline in the early 1970s may be an artifact arising from use of different versions of the standard classification.) Figure 2 provides information in the same format for PMF, and shows a similar trend [ ]

Jan 1, 1993

By Lin-fang Shen, Shao-jun Li, Zhi-liang Wang

"The meso-structure of real soil consists of numerous particles with different sizes, while the traditional reconstruction method of quartet structure generation set (QSGS) produce relatively uniform soil particles resulting in significant discrepancy between the actual structure and reconfiguration model. In order to remedy the deficiency, the QSGS is improved by considering the influence of porosity and autocorrelative function of soil, which make the models closer to the real soil. Based on the reconfiguration model, Lattice Boltzmann method is combined in the algorithm to conduct further simulation of fluid flow in soil pores. The D2Q9 model is applied to construct the two dimensional model for simulating mesoscopic seepage field of saturated soil by setting the non-equilibrium extrapolation scheme at the inlet and outlet boundary, and the bounce-back scheme at the soil particles boundary as well as the left and right boundary. According to the case study, the proposed program is realized to simulate mesoscopic seepage field of reconstructed soil with constant inlet seepage velocity. The results show that the seepage direction of soil is along the passage with good connectivity, therefore the permeability is controlled by these passages. The seepage velocity in such channels is faster than in bad connectivity channels. Even if the channel has larger pores, the seepage velocity is still small. INTRODUCTIONUnderstanding the seepage mechanism in porous materials is significant in both theoretical and engineering problems. As a typical porous media, soil consists of solid particles and voids, which form connected channels allowing water to flow through. Such seepage in soil exists widely among geotechnical project of slope, foundation pit, and tunnel, etc. Meanwhile, a number of engineering accidents are caused by limited knowledge of seepage characters in soil (Huang, 2006; Liu, 2013). The conventional method in describing seepage features mostly based on the parameter of permeability, which is a macro statistic mean evaluating the whole connectivity of soil. Obviously, this parameter cannot exactly reflect the details of how water flows through the inner soil structure, especially the flow velocity in local mesoscopic area, hence is unable to represent the actual seepage properties. Therefore, it is necessary to develop mesoscopic approaches to fully study the seepage mechanisms."

Jan 1, 2015

By Mario Samamé Boggio

El presente texto señala los progresos recientes respecto de la siderurgia y la ferrominería en algunos países de América Latina. En el caso de Argentina, la vanguardia tecnológica radica en el aumento de la capacidad productiva y la tendencia hacia una aminoración en la tasa de crecimiento del consumo interno, crecimiento de la producción, exportaciones y en los problemas de abastecimiento interno y externo de chatarra y semiproductos. En el caso de Brasil, el sector de aceros tiene relevancia con la inauguración de la plan a de la empresa Acos Finos Piratini, en Río Grande do Sul. Esta cuenta con instalaciones de reducción directa, donde se utiliza carbones pobres de la misma zona y con capacidad para 65.000 t por año de fierro esponja. La industria siderúrgica de Colombia mostró en J 972 nuevos avances en sus cifras globales de producción de acero y en sus niveles de productividad. En Chile, la Compañía de Acero del Pacífico se dispone a construir una planta de peletización, que utilizará finos provenientes de sus minas de Algarrobo y Boquerón Chañar. En Ecuador, la empresa ANDEC, que está operando a un nivel de 30,000 t. anuales de laminados, definirá su programa para encarar la producción de barras en rollos y alambrón. Finalmente Perú, definió su programa de desarrollo siderúrgico, el cual contiene inversiones que para 1990 sumarán unos mil millones de dólares.

Mar 1, 1975

The reliable estimation of ore reserves in mineral sand deposits depends on drilling methods and assay techniques that have been specially developed within the industry. Improvement of these techniques is a continuing process, as variations within and between deposits are highlighted during the actual mining operation. Constant monitoring of metallurgical losses along with mineral production allows comparison of mineral tonnages accounted for by mining, with original calculated reserves. A review of ore reserves in the Jerusalem Creek field from scout drilling in the sixties, through mining in the seventies, shows the progression from understatement prior to mining, to the present when more than two thirds of the reserves have been depleted.

Jan 1, 1979

By E. Yalçin

The data set often contains one or more secondary variables. These secondary variables are usually spatially cross correlated with the primary variable. The addition of the cross-correlated information reduces the variance of the estimation error by using the cokriging method. The grade estimation results of ordinary kriging and cokriging methods are evaluated and it was found that the estimation variance of cokriging method is slightly lower than ordinary kriging. The effect of variation of block dimension on the estimation results is also investigated and it was seen that the cokriging estimation variance values also decrease as the block dimension increases.

Jan 1, 2005

By R. S. Archer

THE name molybdena was employed by Pliny to denote various substances resembling lead. Later this name was applied to galena-the naturally occurring sulfide of lead-or substances of similar appearance. By the middle of the eighteenth century, it was applied to graphite and to the mineral sulfide of molybdenum (MoS2) now called molybdenite. This confusion is quite understand- able inasmuch as these substances look and feel very much alike. In 1778, the Swedish chemist Scheele published a treatise in which he pointed out essential differences between graphite and molybdenite. On treatment with nitric acid, molybdenite, unlike graphite, produced a peculiar white earth with acidic properties which he called molybdic acid. Since the same mineral gave off sulfurous fumes on heating, he concluded that it was a sulfide of molybdenum. In 1790, there appeared an account of the isolation by P. J. Hjelm of the new element molybdenum, as a metallic powder, by heating the oxide with carbon. It was not until Bertelius conducted the necessary experiments, about 1818 to 1825, that the foundation of the chemistry of molybdenum was laid. The only recorded use of molybdenum during the first century after its isolation was as a chemical reagent, primarily for the determination of phosphorus. It was not until the last decade of the nineteenth century that the use of molybdenum in steel appears to have been investigated. A

Jan 1, 1953

By J. F. Kemp

Introduction The Bulletin of the Institute for March, 1911, is chiefly devoted to papers upon the iron ores of northeastern Cuba. At that time information about the new developments in the peculiar brown hematites of the region was becoming widely circulated and interest was especially keen. For some years exploration had been conducted with pits and trenches and so great an area had been shown to contain ore in the Mayari, Moa, and Cubitas or San Felipe districts, that the reserves conveniently situated for the consumption of American furnaces were estimated as quite two billions of tons. In the subjoined footnote will be found a list of the principal papers of special interest which have already been published.1 The further remark may, however, be made that the

Jan 2, 1915

By Robert E. McIvor

"Use of the Bond Work Index to size industrial grinding equipment was widely known. Bond also described its application for measuring grinding circuit efficiency. Bond Work Index efficiency also has been used extensively by industry, but until now without concise standard methods, or a formal guideline, for doing so. The Bond Efficiency Sub-Committee of the Industrial Comminution Efficiency work group of GMSG has produced such a guideline, which is appended hereto. It covers the methods and provides examples of how to calculate the Bond Work Index Efficiency of most industrial grinding circuits. Bond Work Index testing equipment and methods are also provided.Comminution is responsible for a major portion of mineral processing plant energy consumption and operating costs. Bond Work Index efficiency provides valuable means, first, for benchmarking one’s plant performance against others in the broad industry, and hence defining the extent of the opportunity for improvement. Secondly, improvements in circuit efficiency with implemented changes can be quantified and monitored as part of continuous improvement efforts. These two important business activities are thus facilitated, and, in the absence of any other accepted method, otherwise would be lacking without the existence and application of this standard for comparison. While often loosely applied in the past by plant metallurgical staffs, the increased precision offered by this guideline provides much clearer definition of both the conceptual and statistical meaning of these measurements. Even a small improvement can be enormously financially important, but only if differentiated by measurement. This guideline was thus intended to provide industry improved means to differentiate comminution circuit efficiencies. Carbon footprint reduction is coincidental, but nevertheless can be substantial.The next steps are: (1) to establish standard reference testing materials and one or more laboratories to serve as bases for reference testing; (2) to establish the accuracy of relative circuit Work Index Efficiency determinations; and (3), to develop and provide a public data base of industrial comminution circuit Bond Work Index Efficiencies."

Jan 1, 2016

By A. J. Burger, F. L. D. Cloete

Tests indicated that effective recovery of pyrite from a coarse Witwatersrand quartzitic ore can be accomplished by intensified flotation in an air-sparged hydrocyclone. Air is fed through the porous cylindrical wall of the hydrocyclone into a swirling layer of slury. Hydrophobic particles are attached selectively to small air bubbles, which form a froth and are recovered through the overflow. Hydrophilic particles pass out in the underflow. A spigot in which flow is restricted by an orifice was found to be more successful in preventing blockage by wood chips than an annular opening between a pedestal and the cylinder wall. Pyrite recoveries of 85 to 93 per cent at grades of 35 to 40 per cent sulphur were obtained in the air-sparged hydroclone with residence times of about 1 second. Comparative tests in a batch flotation cell after 320 seconds yielded average recoveries of up to 96 per cent, but with a mean grade of 32,5 per cent sulphur. A high colector dosage of 120 g/t was required in the cyclone, compared with the 40 gft used in conventional operations. An air flowrate of about 150 I/min was adequate at a slury feed rate of 35l/min. Particle sizes between 38 and 106µm yielded the best flotation results.

Jan 1, 1988

By F. W. Jessen, H. Kazemi

A washing technique has been developed to form a spherical cavity in massive salt. The technique is, basically, a process of controlling the fluid motion in the cavity, the concentration distribution of brine, the rate of dissolution at the walls of the cavity, and the particular settings of the wash pipe, or pipes (inlet and outlet pipe) employed. For a particular arrangement of tubing and casing, fresh water enters from the casing annulus at a position above the bottom of the tubing, and the dissolved material leaves the cavity through the tubing near the bottom of the projected hole. The initial configuration of the cavity is cylindrical, representing the drilled hole situated at the axis of the projected cavity. As washing progresses the original hole is enlarged radially (any direction perpendicular to the axis of the hole). An inert fluid (generally a hydrocarbon, natural gas, or air) which serves as a blanket is injected through the annular space between the original hole and the casing. The controlled downward motion of this blanket maintains the upper edge of the brine region that is expanding on the surface of the projected sphere. A large spherical glass container and a radial model were used to investigate the flow patterns and the concentration distribution of brine occurring during the progress of solution of the salt. Aluminum flakes and dye were injected and flow patterns were observed and recorded on motion picture film. Based on the results of these model studies and other work carried out in this laboratory, the controlled washing technique was formulated. INTRODUCTION Underground cavities leached in salt beds and salt domes have been used extensively for storing hydrocarbons. Little attention has been focused on the shape of the cavities as long as large volumes were obtained and the cavities were structurally stable. The general process involves circulating fresh water and removing brine. Two distinctly different circulating systems can be employed, each of which yields characteristically different shapes. By far the most generally accepted method of washing storage caverns in salt domes is the direct circulation system. Water is introduced through the innermost pipe of a concentric pipe system, and brine is withdrawn through the annulus. In the reverse-circulation method, water enters through the annulus and is discharged through the smallesc tubing string. The size of the operation, and hence the size of tubing and casing used, depends on such factors as cavity volume, length of hole, availability of water, disposal of brine and power requirements. Underground caverns are from 100 to 1,000 ft or more in length, and when completed vary from 40 to 100 ft in diameter, providing storage of 100,000 bbl or more. The volumes of water required per volume of salt removed vary from 6 to 7 for the reverse circulation method to 10 to 11 for the direct circulation method. Up to 80,000 BWPD are often circulated. In the direct circulation method, because water enters near the bottom of the projected cavity, solution of salt is greatest at this point, particularly in view of the fact that when the washing is begun turbulent flow undoubtedly exists in the immediate vicinity of the discharge of the inlet water. As the diameter of the hole increases, flow rates also are increased, so perhaps the condition of fluid turbulence is maintained for some time. During the later stages of leaching, when capacity of equipment may be the limiting factor in maintaining flow rates, there may still exist some turbulence adjacent to the point of influx; however, for the most part laminar flow conditions prevail. There appears, therefore, rather good evidence to indicate that the state of fluid motion is responsible for the typically shaped cavity which results from such washing — namely a cylindrical form, generally somewhat larger at the bottom than at the top. Depending on the number of so-called stages which might be employed, the walls or surfaces of the salt diminish rather uniformly from bottom to

Jan 1, 1965

By O. K. Mahabadi, A. Lisjak, B. S. A. Tatone, N. Vlachopoulos

"Numerical simulations are widely adopted in the design of several types of rock structures, including tunnels, caverns, rock cuts, and open pit and underground mines. In recent years, analyses based on the hybrid finite-discrete element method (FDEM) have been shown to provide a realistic representation of rock mass deformation and fracturing processes. To date, the FDEM approach has successfully yielded qualitative and quantitative results for several practical rock engineering applications, yet it has lacked the ability to consider the implementation of rock-reinforcement measures. Since rock reinforcement is often used in civil and mining applications to improve the strength and deformational behaviour of a rock mass, the ability to incorporate such features into FDEM analyses is essential to extend its applicability to a broader range of problems. The work presented in this paper represents an important first step towards developing a simulation tool that can be used for practical rock engineering applications, including the design of underground excavations and rock slopes.INTRODUCTIONRock support and reinforcement measures are often employed in civil and mining rock engineering projects in order to maintain or improve the strength and deformational behaviour of rock masses. The preferred type of reinforcement or support elements along with the preferred layout and timing of installation depend on the in-situ ground conditions, the nature of the rock mass and excavation method. Over the last two decades, numerical modelling has been increasingly used to design and attempt to optimize rock reinforcement and support systems. As such, most rock engineering-specific modelling software now offers various approaches for modelling different rock reinforcement and support elements."

Jan 1, 2015

By Jorge Vargas Fernández

El presente texto describe el diseño de una política minera como parte de una estrategia de difusión. Para tal efecto, esta se divide en dos parámetros: internacionales y parámetros nacionales. En ese sentido, el marco y referencia internacional es analizado con ayudas de gráficos estadísticos y cuadros que comprende: las fuerzas que actúan en la industria minera, crecimiento de producción minera mundial, relación del crecimiento industrial con el consumo, la comparación entre la producción y consumo de las principales sustancias por zonas, etc. Asimismo, con la finalidad de promover las inversiones en minería, es importante revisar la legislación laboral, de modo que la ley de estabiidad no rija para las empresas mineras que tienen alto riesgo

May 1, 1987

By M. R. Geer

American and European practices in cleaning fine coal are strikingly different. The tables, launders, classifiers, and pneumatic devices used in America are seldom employed in Continental Europe, where much of the fine coal is cleaned in feldspar jigs, often supplemented by froth flotation of the extreme fines. This difference in choice of cleaning equipment may be fortuitous, but in large measure can be attributed to a difference in economic factors. Coal being more costly in Europe, there is greater emphasis on efficient cleaning of all sizes, including the extreme fines, and it is common to produce a high-ash middling for "on-site" consumption to avoid any waste of fuel value. The feldspar jig has been found advantageous under these conditions. In the United States fuel coal must be prepared as cheaply as possible, and metallurgical coal must be prepared as efficiently as possible; thus in both branches of preparation practice, any cleaning device that promises greater economy or higher efficiency warrants consideration. The feldspar jig, as employed in Europe, has a much higher unit capacity than the wet table used so extensively here and therefore offers economy in the capital costs of a washery through saving in space. As pointed out by Vissac,4/ the jig operates under automatic control, and therefore can cope with fluctuations in quality of feed. Maintenance costs for a single, large-capacity unit, such as the feldspar jig, would be expected to be lower than those for a battery of low-capacity cleaners. These considerations led the Bureau of Mines to undertake an investigation of the feldspar jig to determine its possible usefulness in this country.

Jan 1, 1958

By W. Dziurzynski

Transient states of the air parameters in mine workings occur as the effects of natural and technological disturbances, and in particular as a result of changes in ventilation conditions, caused by alteration of the mine workings geometry, state of fans performance or emission of gases. Particularly significant are those transient states caused by disturbances resulted from catastrophes, since they are frequently associated with violent phenomena that may be a danger for life and health of the staff working underground. The paper presents a number of examples of transient states of the air parameters in mine workings after a catastrophe, like the bump in the ZABRZE-BIELSZOWICE coal mine. Registration of air disturbances by the monitoring systems of ventilation in mine workings in the area of disaster both at the moment of a catastrophe occurrence and later during the rescue operation, enabled to track out the incident and identify the circumstances and reasons of those tragic events which caused death of 18 miners during last two years. Furthermore, computer simulations of processes occurring in mine ventilation network make effective research tools to be applied in practice, among others for the study of accidents and disasters.

Jan 1, 2003

By Al Campoli

One of the critical variables affecting resin bolt performance is the size of the resin annulus, defined as the difference between the hole and bolt radius. The vast majority of the millions of resin roof bolts installed each year in the United States employ an annulus between 0.125 and 0.188 inch. As the annulus size decreases the resin flow around the bolt becomes more difficult, increasing the resin pressure induced by bolt insertion. As the resin pressure increases the loss of resin into bedding planes and vertical fractures in the rock increases. As the annulus size increases the mixing of the resin paste and mastic becomes less efficient. Thus, the lower and upper limits of the optimum annulus size is determined by insertion pressure and mixing considerations, respectively. Previous U.S. Bureau of Mines researchers have concluded that a 0 125 inch annulus is optimal. However, others have recently reported that a 0.095 inch annulus with special rolled deformation (SRO) bolts provide superior anchorage to standard rebar with a very large 0.250 inch annulus, attributing SRD resin loss in weak ground to oversized holes. The effect of annulus size on unit length pull strength and resin loss to fractured rock was investigated. Short encapsulation pull tests with resin annuluses of 0.125 and 0.095 inch resisted an average of 2.25 tons per grouted inch, with no significant variation. However, annulus size has shown a dramatic effect on the magnitude of resin lost to simulated rock fractures. No. 5 standard . No. 6 standard, and No 7 J-Bar rebar were inserted into two different viscosity resin cartridges designed for 4 foot boll encapsulation into a one inch inside diameter metal tube, To simulate a rock fracture, a 0.250 inch diameter orifice was located near the capped end of the tube Resin loses increased as annulus size decreased, with a minimum loss of 35% and a maximum loss of 60% associated with 0.125 and 0.095 inch annuluses, respectively.

Jan 1, 1999

By J. -F. Lagueux

Goldex Mine is an underground mine located near the town of Val-d?Or. Multiple innovations were required to work the mine. Due to its low grade, it was important to develop a bulk mining method to economically extract the ore. The method used is a combination between shrinkage stope and long hole stope methods. This modified method is more than adequate; however, all of the ore body must be liberated in a very short period of time. Therefore, to bring down 23 Mt of ore, large blasts up to 1.8 Mt are required. The situation is also complicated by the fact that the mine is located in a residential area. No less that 40 homes are built within a 1 km radius of the mine site. In addition to managing mass blasts, means must also be found to mitigate the vibrations produced by the blast to diminish the disturbance to the neighbourhood. Therefore, the mine used numerous tools to properly plan the blasts and reduce the impacts. A program to control vibrations was one of the first tools put in place. The program?s aim was to draw up an action plan to ensure a follow-up of the homes by inspecting them. The second tool was to develop a methodology to plot a reliable attenuation curve and to adequately determine the maximum charge weight for each blast. Finally, effective communication tools were developed to inform the neighbourhood. There was a huge amount of work to be done in relation to the bench. Reliable and fast loading techniques had to be found to load large blasts in a very short period of time. Adequate logistics had to be developed to send underground more than 20,000 kg of emulsion per day while performing the daily underground operations. Technology had to be developed to adapt the i-kon electronic blasting system to large blasts. Since the control of the charges was the major factor to reduce surface vibrations, it was important to employ loading techniques that would permit decking of the long holes to reduce the charge weight per delays without adversely affecting the loading. All of this work requires an enormous amount of energy but also close collaboration between the different stakeholders (various departments, suppliers and consultants).

Jan 1, 2011

By Paul H. Johnson

Resource Engineering and Development, Inc. is designing and building a portable 150 to 225 TPD, flotation-cyanide leach plant with unitized, skid-mounted components. This plant design, with its portability, low capital investment, and high recovery of silver and gold from many partially oxidized ores, is well suited to treat many small, high-grade deposits, old waste dumps, and old mill tailing piles. A description is given of flotation and/or cyanide leach tests run on about 17 partially oxidized, newly mined ores; waste dump materials; placer slimes; and old mill tailings.

Jan 1, 1981

By John E. Udd

"Mining research at CANMET is delivered by the Mining Research Laboratories Division (MRL), with facilities in Sydney, Nova Scotia; Bells Comers, Elliot Lake, and Sudbury, Ontario; and Val d'Or, Quebec. This paper gives an overview of the work of the Division as of early 1993. An addendum, at the end of this paper, describes the organizational changes that will take place in April 1994. IntroductionCANMET, the acronym for the Canada Centre for Mineral and Energy Technology, is the name by which the organization founded in 1907 as the federal Mines Branch is presently known. The name was changed in 1974, in order to give recognition to the importance of both minerals and energy technologies in the activities of the Branch. Further reorganizations have taken place since 1987. As a result of these, CANMET has assumed the status of a Sector (equivalent to the Geological Survey of Canada) and has been organized into four branches.The organization as a whole functions in an environment of semi-matrix management. Some of the ""line"" Divisions report to Directors-General for the appropriate branches while other, larger divisions, report directly to the Assistant Deputy Minister.The second dimension of the organizational matrix is composed of a number of ""staff' divisions which report to the DirectorGeneral for Policy and Planning. Each of these Divisions performs a function which is common to all of the ""line"" divisions. For example, the Research Projects Office is responsible for monitoring the range of research activities of CANMET and for recommending allocations of funds for both research contracts and operating budgets. The Library and Documentation Services Division is responsible for CANMET publications and information services. Likewise, the Engineering and Technical Services Division provides support through, among other services, the construction of specialized laboratory equipment."

Jan 1, 1994

By Miller JD, Ye Y

The Air-Sparged Hydrocyclone (ASH) has been developed for the fast and efficient flotation of fine mineral particles in a centrifugal field during the past decade at the University of Utah. Over the years, the air-sparged hydrocyclone unit has shown promising potential for the flotation of copper porphyry ore, low-grade placer gold and auriferous pyrite ores, various industrial minerals, and fine coal cleaning. Many fundamental studies including the X-ray computed tomography (CT) analysis have been carried out in order to understand the multiphase fluid flow phenomena associated with ASH flotation. With data available from these studies, it is now possible to construct more accurate ASH flotation models for different applications in order to analyse the behaviour of the system and to optimise design and operating variables. The ASH flotation model developed in this paper is based on the data given in `Air-Sparged Hydrocyclone/Advanced Froth Flotation Fine Coal Cleaning', Final Report, DOE Contract No DE-AC-88PC88853, submitted by Pennsylvania Electric Company (PENELEC), December 1989. Data from several hundred experiments with the two-inch ASH-2C air-sparged hydrocyclone (capacity 0.1 - 0.3 tph dry coal) are available from the report and have been used for this analysis. In the past, a preliminary model based on limited data had been developed. The current study, however, emphasises the global behaviour of the ASH system by utilising almost all the data from the report for the purpose of scale-up and industrial application. There are two parts in the current modeling and analysis effort for ASH flotation of fine coal. The first part is the modeling/analysis of dimensionless ratio of overflow opening area to underflow opening area, A*, and the dimensionless ratio of air flowrate to slurry flowrate, Q . The second part involves the modelling/analysis of all other variables in the system and an expert system for operation and control is introduced.

Jan 1, 1993