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By Patrick D. McMaster

"INTRODUCTION According to the Roane Iron Co. of Rockwood, Tenn., the Chamberlain. Barnardville iron deposit produced approximately three million tons of iron ore previous to 1928. The deposit is divided into two synclinal bodies termed the north and south synclines. Production has come from the northern extremities of both bodies.The need for developing additional iron-ore reserves during the war prompted the Bureau of Mines to initiate an exploratory program on the Chamberlain-Barnardville deposit in February 1944, which continued until December 1944.ACKNOWLEDGMENTSIn its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, R. G. Knickerbocker, chief, analyzes samples and performs beneficiation tests. Both these branches are under the supervision of Dr. R. S. Dean, assistant director."

Oct 1, 1946

By John P. Hager

One possible approach for the recovery of mercury from acid plant blow-down sludge in smelters is the use of a vacuum retort reactor for the vaporization of the mercury with subsequent collection of metallic mercury in an attached condenser. An experimental study was undertaken to investigate the vaporization of mercury when present as a compound in the Hg-S-O and Hg-Se systems. A transpiration reactor was modified to operate under reduced pressure and with a continuous flow of inert sweep gas. A water-cooled cold finger was inserted into the exit end of the reactor to provide for the rapid quenching of the exit gases and the collection of the mercury. Rates of vaporization were measured at several temperatures for each compound and were generally found to be constant at a given temperature and reactor pressure. The results were used to determine the minimum operating temperature for 100% vaporization of the compound in 60 minutes. For Hg2SO4, HgSO4, and HgSO/2HgO the required temperatures. for a reactor pressure of 50 Torr. were determined to be 634°, 622°. and 603°C. respectively. For HgO, HgSe, and HgS the required temperatures were 557°. 451°. And 382°C. respectively. For HgS the rate of vaporization was also measured at a reactor pressure of 1 00 Torr. The rate of vaporization was found to be slower resulting in an increased vaporization temperature of 423°C. It was also determined that the mercury vapor present in the exit gas stream can back-react with the other gas species to a significant extent and can result in very little condensed metallic mercury. For the vaporization of both HgS and HgSe. the mercury vapor was found to have back-reacted to the extent that virtually none of the vaporized mercury was collected in metallic form. For the vaporization of Hg2S04? HgS04, and HgSO4*2HgO the amount of metallic mercury recovered varied from approximately 50% for HgS04*2HgO to approximately 10% for Hg2S04 and HgS04. Only for HgO was the recovered mercury in primarily elemental form. The application of the results to the operation of a vacuum retort and condenser system is discussed.

Jan 1, 2001

By E. J. Gleim

A list of permissible mine equipment, tested and approved by the Bureau of Mines previous to January 1, 1942, was published in Bureau of Mines Information Circular 7207.3/ The list of that date was complete as to equipment then available and in current use. Information Circular 7240,4/ published as a supplement thereto, listed equipment approved curing the calendar year 1943. The present list is another supplement covering approvals issued during the calendar year 1943. The items are numbered to indicate the consecutive order in which each type of machine or device was approved in its particular classification. Thus, Information Circular 7207 gave 19 drills and drilling machines on the Bureau's active list. No additional approvals were given in 1942, but the three issued in 1943 bring the total to 22. Item 102, under Loading Machines and Conveyors, also appeared in Information Circular 7207, and items 120 and 124 appeared in Information Circular 7240. These numbers are repeated here to show that approvals were granted during 1943 for additional voltages on machines previously listed for one voltage only. Equipment listed in these circulars is approved by the Bureau of Mines only when found upon inspection and test to comply with minimum standards of safety as outlined in schedules prepared on the basis of many years of experience in dealing with safety problems of the coal-mining industry. The use of such equipment in mines known to be gassy, as well as in those that may become so, is earnestly recommended in the interests of safety. This circular is published so that the industry may be kept

Jan 1, 1944

By H. S. Geismer

INTRODUCTION. THERE are three general methods available for obtaining commercial brown iron-ore : hand-screening; washing; and washing and concentrating. Hand-screening has produced a large tonnage of ore in the past, but is rapidly falling into disuse, except as a preliminary step, largely because modern furnace-practice requires all foreign material to be separated from ores before they are delivered to the furnace, and hand-screened ores can rarely be made to fulfill that requirement. Another argument against hand-screening is, that the waste-pile often contains as much ore as the screen recovers. The operation known as hand-screening consists of throwing the ore-bearing material against a stationary inclined screen of 0.5- to 0.75-in. mesh, similar in construction to the screens employed in sand-pits. The recently-prospected brown-ore deposits of Cuba seem to offer possibilities for hand-screening not possessed by the average American deposit, since these ores are not associated with worthless clays. Washing, and washing and concentrating, may be discussed together, since concentrating is never practical on brown iron-ore, except to treat ores that have already been washed. (Strictly speaking, washing might be classed as concentrating, but it is never so designated by brown-ore men.) The various steps of removing ore-bearing material and converting it into ore suitable for blast-furnace use, may be grouped under five heads: loading for transportation ; transporting ; feeding into the washer; washing; and concentrating. These five subjects will be considered in consecutive order. Each of these successive steps may be accomplished in a number of different ways, the choice depending entirely upon the character of the ore-bearing material to be treated.

Aug 1, 1911

By J. Petersen, T. Moyo

Waste Printed Circuit Boards (PCBs) are a metals-rich fraction of electronic waste (e-waste) streams, and globally it has been demonstrated that they can be recycled gainfully to recover the metals. Reported successful cases of PCB recycling are carried out in large volumes, using high-level technology and high capital investment smelter house operations. This presents entry barriers for recyclers in developing economies where capital may not be accessible, and the waste volumes are not sufficient to warrant large scale operations. Hydrometallurgical processes have the potential to provide an option for the scalable processing of smaller volumes of PCBs and can be set up at relatively lower capital costs. However, to date, the hydrometallurgical treatment options available rely on precursor communition and classification processes that also require high capital and energy costs. This paper presents an overview of the work done under the Minerals to Metals signature theme towards understanding e-waste recycling processes and developing pre-processing and characterisation of PCBs in order to unlock potential for local end processing in developing economies, using South Africa as a case study. The structure of PCBs is reviewed, and the current size reduction techniques and the subsequent leaching processes are discussed. Keywords: Printed circuit boards (PCBs), PCB structure, pre-treatment, liberation, ammoniacal leaching

Jan 1, 2020

By Wilhelm Wendt

About five years ago we showed that it is possible to use the spectral in- formation in the light emitted by the off-gas flame of a PS converter for on-line production control. Very recently measurements have been performed using improved optical equipment and data evaluation software, resulting in both improved accuracy and the establishment of new optical process parameters. Using the optical signals the slag heats could be stopped at a predetermined Cu content of the white metal with an accuracy of +0.2% Cu m the range 74-78% Cu. A good correlation was found between the slag composition and optical data, providing a possibility for on-line monitoring of the SiO2 content of the slag. The measurements indicate the possibility of predicting the optimum end-point of the copper-making stage and having real time information on the impurity removal. Factors influencing the optical parameters, such as blowrate, Pb content, temperature etc. will be discussed.

Jan 1, 1993

By Marcia Harris, Richard Mainiero, Michael Sapko

Since 1988, there have been 17 documented incidents in the United States and Canada in which carbon monoxide (CO) is suspected to have migrated through ground strata into occupied enclosed spaces as a result of proximate trench blasting or surface mine blasting. These incidents resulted in 39 suspected or medically verified carbon monoxide poisonings and one fatality. To better understand the factors contributing to this hazard, the National Institute for Occupational Safety and Health (NIOSH) carried out studies in a 12-foot diameter sphere to identify key factors that may enhance the levels of CO associated with the detonation of several commercial trenching explosives. The gaseous detonation products from emulsions, a watergel, and ANFO blasting agents as well as gelatin dynamite, TNT, and Pentolite boosters were measured in an argon atmosphere and compared with those for the same explosives detonated in air. Test variables included explosive formulation, wrapper, aluminum addition, oxygen balance, and density. Major contributing factors to CO production, under these laboratory test conditions, are presented. The main finding is the high CO production associated with the lack of afterburning in an oxygen poor atmosphere. Fumes measurements are compared with the manufacturer’s reported IME fume class and with the Federal Relative Toxicity Standard 30 CFR Part 15 in order to gain an understanding of the relative toxicity of some explosives used in trench blasting.

Jan 1, 2003

By Bruce A. Kennedy

The 1960's were an apparent turning point in the technological and social attitudes and awareness of the mining industry. From the late 19th century through to the early 20th century, one has always been presented with the picture of the rough and ready leaders of the mining industry who screamed for production and damned anything that got in the way of it. This attitude led to a certain alienation of the mining industry in the eyes of the general public. They saw an industry which was archaic in many of its practices and often heartless in its attitudes towards mankind. However, a gradual change spread through the industry and cracks began to appear in the hard facades of the mining companies. Resistance to change had almost become a standard operating procedure for many and consequently changes in technology had been slow in coming. The late 1950's and the 1960's saw a new awareness come into existence. As the mining company managements changed, there developed a realization that considerable efforts had to be made to bring the technology and social standing of the industry out of the dark ages and into the modern world. New advances were made in both metallurgical and mining technology. The 20th century technology of computers was accepted and became a standard tool of the industry.

Jan 1, 1971

By A F. D C Varajpo, R C. Weba, C Volkmer-Ribeiro, C A. C Varajpo, N S. Gomes

This study relates to the spongillite deposits from the region of Jopo Pinheiro, in the north-west of the State of Minas Gerais, south-eastern Brazil. The deposits occur in shallow ponds (with a maximum depth of 3.5 m) on a karstic planation surface developed on rocks of the Spo Francisco Neoproterozoic Supergroup. Cenozoic detritic covers are associated with this surface. The field study of spongillite deposits from the Preguita and Avipo deposits revealed sedimentological and pedological similarities between the different deposits. They have a lenticular shape and contain different layers of sedimentary spicules intercalated with layers of quartz sand and clay minerals. Representative samples from the different layers investigated by X-ray diffraction, differential and gravimetric thermal analysis and infrared spectroscopy showed a range from three to 80 per cent of amorphous silica (opal) corresponding mostly to the sponge spicules in the sediments. Optical microscopic investigation determined that the spicules predominantly belong to the sponge Metania spinata. This species is represented by smooth megascleres (alpha type), prickly megascleres (beta type) measuring 240 to 450 mm in length, as well as the spiny microscleres; whereby the smooth megascleres are larger and thinner. The morphological variation of the spicules as well as the presence of more fragmented spicules towards the base of the deposits, portray a variation in texture and in the state of their preservation along the profile, suggesting environmental variations at the time of their formation and deposition.

Jan 1, 2008

By M. Gershon

Four computerized approaches for coal blending are described and their strengths and weaknesses are explored. Spreadsheet analysis Other than word processing, spreadsheet software is the most commonly used software. Its wide availability and ease of use are two desirable features that have led many to try to adapt it to the purpose of coal blending. These are the two main advantages of this approach. To use a spreadsheet for coal blending, each row of data represents one source of coal. Each column represents a quality of the coal, with the last column specifying the tonnage of that coal in the blend. The calculated figures are the blended qualities, which can be programmed to appear in the bottom row. A trial-and-error approach is then used to develop the best blend. Inserting any blend in the last column provides the blend characteristics at the bottom of the page. If any specifications are not met, the blend can be changed, all calculations being immediately updated. This process is repeated until all specifications are satisfied. A third advantage of this method is that it is exactly the procedure that one would go through if doing this by hand. With a spreadsheet, many more blends can be evaluated in much less time, allowing the designer to try to improve over satisfactory blends to find the best of them. The resulting improved blends or cost savings are a fourth advantage of this approach. There is only one major disadvantage of using the spread-sheet. This is that most probably the best blend is not found. As an inexpensive introduction to computer-assisted blending, which can be easily understood and cost just a few hundred dollars, this is a recommended place to begin. Computerized search Computerized search approaches represent crude first attempts at letting the computer design the blend. Unfortunately, the blends found by these programs are very often less satisfactory than those developed manually. The way these techniques work is that they design, according to some predesigned pattern, a number of different blends and then quickly evaluate them. It is then straightforward to select the best from this sample set. The quality of the results depends on the number of blends designed, the way they differ from each other (the search procedure), the number of sources available, the number of quality specifications, and the severity of the specification limits. Good results are usually obtained for small, simple problems. At best, the results obtained are inconsistent from one blend to the next. Programs of this type are advertised in the mining literature. They usually mention how many different blends are evaluated, making it clear that this is more than can be tried manually. Expert systems Expert systems use a source of information known as a knowledge base. The knowledge base, usually a set of if-then rules, attempts to reconstruct the deductive reasoning process of an expert in some job capacity. For coal blending, the usual trial-and-error process has an easily recognized pattern of rules that are followed to try to find a better blend. By following these rules, it is possible to home in on the best blend without the exhaustive search required by the previous method and without the manual manipulation of the spreadsheet approach. The use of an expert system accomplishes this. One of the rules may say something like "if BTU is out of spec, then add more in the blend from a source having a high BTU and subtract some from a source having low BTU." In other words, it goes through the trial-and-error process. The process continues until all specifications are achieved and can continue further to try to optimize the cost. Of course, less simplistic rules are also needed. One set of rules would determine maximum changes in the tonnage added or deleted to the blend or from any one source. Other rules would be needed to determine which quality to improve if two or more are out of spec. At this level, the process of building the knowledge base provides the engineer with a deeper understanding of his or her own thought processes. The advantage of obtaining better blends is clear for this approach. Two more advantages should also be apparent. One is that it follows the same common sense logic that is used when doing the blends by hand or by spreadsheet, making it easy to understand. The other is that, like the search procedure, it designs the blend rather than just analyzing manually designed blends. Thus, it has all the good features of both approaches discussed thus far while providing improved results over each. A final advantage is the ease of use and ease of development. The expert system shells that are on the market are very easy to use and can be run on microcomputers. Linear programming Linear programming is an algebraic tool that solves a set of linear equations to yield an optimal solution to a problem. The optimal solution is based on the linear model so the results are only as good as the ability of the linear model to accurately portray the reality of the problem situation. It is fortunate for the coal blending problem that a linear model can be devel¬oped that reflects exactly the problem that is required. Unfortunately, the mining industry has been slow to use this tool. Coal blending applications available that use linear programming take one of three forms. The first, requiring exper-

Jan 12, 1988

By Bruce K. McKnight

"The new H-W orebody was evaluated by considering its production at three technically feasible rates. Capital and operating costs were estimated f or each rate and production sequences were established using mining cutoff limits generated by an ore value algorithm. The viability of the project was then examined by conducting economic and financial analyses of each of the three production cases under various world economic scenarios. These analyses employing standard profitability measures demonstrated all three cases would be economically viable; the production case which maximized the Net Present Value of the project was the one selected for development and production.IntroductionWestmin Resources Limited and its predecessor company, Western Mines Ltd., has been continuously carrying out mining operations near Myra Falls in Central Vancouver Island since December 1966. The mining operation, whose current production rate is approximately 830 tonnes / day (t/d), based on ore derived from the Myra and Lynx Mines, produces copper, lead and zinc concentrates which contain significant quantities of gold and silver in addition to the base metals.In the late 1970s, with Lynx and Myra ore reserves slipping to unacceptably low levels, a major increase in mine-site exploration was initiated, with outside geological staff brought in to complement the efforts of the mine's geological staff. By the end of 1979, this program had resulted in the discovery of a significant new orebody on a deeper horizon some 300 metres below the one which hosts the Lynx and Myra deposits. Throughout the period 1980-1982, major drilling was carried out to evaluate the new H-W deposit and by the end of 1982, drill-indicated mineral inventory for the deposit compared with Myra, Lynx and Price ore reserves was as shown in Table I. During this same three-year period, a major development and evaluation program was underway comprising environmental monitoring and control programs, shaft sinking test mining, bulk sampling and mill testing, rock mechanics studies and preparation of the Stage I and II reports for the multidisciplinary Environmental Land Use Committee (ELUC).As a result of the preliminary engineering work and exploration drilling, it became rapidly apparent that the H-W deposit could support a considerably higher production rate than the current one. Accordingly, engineering studies including scheduling of development and production as well as capital and operating cost estimates, were focused on three possible production rates: 1350, 1800 and 2700 t/d. Our task was to select the optimum one of these three rates."

Jan 1, 1987

By A. S. C. Owili-eger

An efficient state-of-the-art dynamic model to simulate and predict the rate of water production in longwall coal mining operations was developed as a tool for mine planning purposes. The model can also provide an estimate of any potential resultant hydrogeological impacts of an operation via an array of element-specific single-valued parameters referred to as the field rating indices. The computational procedure was designed to fully exploit the benefits of hydrogeotechnology and utilize a combination of conceptual, physical, empirical, and numerical approaches to define, characterize, analyze, and evaluate flow con- trolling properties of fractured rock systems. The model presented here provides a dynamic prediction method for highly fractured flow; a practical tool in mine and water control planning; and a cost-effective means of assessing, based on the best available technology, the impacts of mining on the water resources within a mining environment to satisfy local and federal regulatory requirements. Unique features include consideration of laminar and non-darcian flow domains in double-porosity-pressure hydrogeological media.

Jan 1, 1987

By Mosquera. J.

Tailings Storage Facilities (TSFs) are vast structures that respond to site-specific characteristics, rate of production, placement techniques, and the physical and mechanical properties of tailings. As a common denominator, TSFs are in some degree vulnerable to failure due to liquefaction, poor management, slope instability and/or unusual climatic events. In practice, stability of TSFS is determined by calculating a minimum Factor of Safety (FOS) using the Limit Equilibrium Method (LEM). However, it has been proven that relying exclusively on the limit equilibrium approach is not accurate because it is basically a static method that does not take into account the stress-strain distribution and displacement experienced by the constitutive materials of a TSF. In order to overcome these limitations of the LEM, the finite element method - Shear Reduction Technique (SRT) has been used as a more reliable tool for TSFs stability assessment. This paper presents a comparative stability analysis between an upstream tailings storage facility (UTSF), and a water retention tailings dam (WRTD) under static and pseudo-static states using simplified and rigorous LEMs and the SRT. Additionally, and taking into consideration the intrinsic uncertainty of tailings properties, sensitivity and probabilistic analyses in the form of Monte Carlo Simulation (MCS) and the Point Estimate Method (PEM) are applied to determine the Probability of Failure (Pf) and Reliability Index (ß) of each TSF. It is shown that the friction angle of UTSF?s foundation and the core?s cohesion of the WRTD are the main variables that govern stability. Further analysis shows that the WRTD has a higher reliability index and a lower probability of failure than the UTSF.

Aug 1, 2013

By L. D. Frink

Those actively interested in mining are fully aware of the ever-increasing difficulty of making conditions such that efficient work can be done in underground openings, especially as higher rock temperatures are encountered in depth. This is also true where an effort is being made to cut down the burden of overhead expense by working headings 24 hr. in a day if blasting is done as often as is possible in that time. That the conditions resulting from both these causes have driven the native-born Americans from the mines and that their places have been taken by less efficient foreigners is a fact that we must all admit. The great war now being fought in Europe and the educational qualification clause written into our immigration law by the last Congress will probably limit very materially the supply of labor, such as we are now using in our mines, and will force upon mine operators the necessity of making this work appeal again to Americans. Metal tubing, with blower or exhaust fans, has long been used in supplying air to dead ends where natural ventilation is impossible, or in driving the smoke from such places, or in doing both, as the need might be. Here in Butte we have now come to use canvas tubing very extensively and find that it has many advantages not possessed by the metal. The use of flexible tubing is not new, but it has not been generally used in mining operations. Recent improvements, however, in the canvas itself and in the jointing of sections and manner of suspension have so increased its usefulness that it promises to add much to the efficiency of mining. There is now on the market a product that is impervious to air, is fireproof, and has a system of jointing which permits it to be put up or taken down in a few seconds. In this article an effort will be made to explain the manner in which canvas tubing is being used in the North Butte company's operations at Butte, Mont. The accompanying photographs will, I hope, help make clear what may be done with this material.

Jan 1, 1918

By W. D. Maier, H. V. Eales

Paper presented at the IAGOD international symposium on mineralization related to mafic and ultramafic rocks held in Orleans, France, 1-3 September 1993. A lithological and geochemical study revealed significant lateral variation of the interval over 170 km of strike, from about 30 m at the Union Section to 220 m near Brits. The cumulates also become more evolved and leucocratic with distance from the Union Section both towards the NE (Amandelbult) and SE (Impala, Rustenburg and Brits). It is inferred that the persistent heat flux from a putative major feeder zone near the Union Section impaired deposition of felsic cumulates in the vicinity, delaying crystallisation of successive phases in parts of the chamber near the feeder. New influxes were therefore deposited on a footwall of varying thickness and lithology in response to different degrees of crystallisation and accumulation along strike. The development of cyclic units of chromitite, harzburgite, pyroxenite, norite and anorthosite was interrupted at different stages in different parts of the chamber

Apr 1, 1994

By T. Fraszczak, U. A. Peuker, T. Mütze, O. Ortlepp

Dolomite is a calcium carbonate sedimentary rock that can be found all over the world. In its calcined form it is employed for water treatment or as an additive in iron production. Calcined dolomite is produced at the Wünschendorfer Dolomitwerk GmbH in shaft furnaces (kilns). Because of an expansion of the mined deposit, significantly higher extraction costs were expected. Therefore, the existing upgrading processes for the kiln stone fraction had to be adapted and improved. This paper presents a process optimisation which allows for an increase of the yield of calcined dolomite by 10 % due to a redesign of the crusher circuit and by an additional 5 % due to a comprehensive characterisation of the kiln stone fraction itself. Here the interdependency between the pressure drop in the furnace during calcination and the size distribution of furnace stones was used to increase the amount of fine size fractions in the furnace feed without deterioration of the calcination process. Keywords: Dolomite, crushing circuits, kiln stone production, flowability, calcination

Jan 1, 2020

By Syd Peng, Gamal Rashed

"Bumps in coal mines have been recognized as a major hazard for many years. These sudden violent failures around mine openings have compromised safety, ventilation and access to mine workings. Previous studies showed that the violence of coal specimen failure depends on both the interface friction and width-to-height (W/H) ratio of a coal specimen. The mode of failure for a uniaxially loaded coal specimen or a coal pillar is a combination of both shear failure along the interface and compressive failure in the coal. Unstable interface failures provide a sudden de-confinement to coal rib, thus triggering uns and compressive failure in the sidewalls. The compressive failure of a coal specimen or a coal pillar can be controlled by changing its W/H ratio. As the W/H ratio increases, the ultimate strength increases. With a proper combination of interface friction and the width-to-height (W/H) ratio of pillar or coal specimen, the mode of failure will change from sudden violent failure, which is brittle failure to non-violent failure, which is ductile failure. The main objective of this paper is to determine at what W/H ratio and interface friction the mode of failure changes from violent to non-violent. In this research, coal specimens of width-to-height ratio ranging from 1 to 10 were uniaxially tested under two interface frictions of 0.10 and 0.25. The results are presented and discussed.INTRODUCTIONCoal mine bumps are sudden, violent bursts of coal from a pillar or pillars or a block of coal, resulting in a section, the whole pillar, or the solid block of coal being thrown into an open entry. These bursts are accompanied by very loud noises (Peng, 2008). Several case histories in mining have long described coal pillars or coal faces failing violently with an accompanying ejection of debris and broken material into the working areas of the mines (Campoli et al., 1987; Osterwald, 1962; Peperakis, 1958; Garvey et al., 2013). Because of the catastrophic nature of these sudden failures, understanding the causes of coal mine bumps is essential to create a safe underground working environment. This phenomenon has motivated many ground control researchers to conduct extensive field investigations throughout the past century. Rashed and Peng (2014) compared the mechanical properties of two kinds of coal, one from bump and the other from non-bump-prone mines. They found that coal itself does not play any significant role in coal bumps and recommended that future research should focus more on the local variation of geological conditions such as the interface friction between pillar and roof and between pillar and floor."

Jan 1, 2015

By M P. Schwarz

A major issue presently faced by companies producing and processing iron ore is the need to maximise throughput while minimising capital expenditure. While present high demand means this is of prime importance, the perennial issues of maintenance, operating costs, reliability, quality and environmental sustainability are also critical to profi tability. Attempts to address these issues generally require modifi cations to existing equipment, or trials of new equipment when designing plant for new projects.The risk involved can be substantially minimised by testing equipment improvements using advanced computational models prior to implementation. Examples of application of Computational Fluid Dynamics (CFD) and Discrete Element Method (DEM) modelling to sampling, cyclones, conveyor transfers, classifiers, dust control, banana screens, comminution and smelt-reduction will be given to illustrate the benefi ts of such an approach. *This is an abstract only. No paper was provided for this abstract.*

Jul 11, 2011

By P. Tapp, T. Evans, N. A. Molloy, J. Lucas

"Consideration of the protoype tuyere geometry for injection of inert gas through the bottom in a basic oxygen steel furnace and a requirement to specify an optimal flow for bottom wear and metal penetration led to experimental investigations[l,2] to apply the results of previous workers to this specific case, Flow velocity profile development within the tuyere was proposed as significant and the experimental scheme was designed to test this. It is proposed that the design criterion for the conditions of optimal flow of the prototype geometry be based on the non-dimensional mass velocity.INTRODUCTIONSharma[3] tested small diameter tuyeres in a laboratory hot model using molten iron to define a flow criterion for prevention of penetration of the bath liquid into the tuyere. Using argon, nitrogen and helium through a range of tuyeres (1 to 3 mm ill ) he proposed the jet Froude number C Fr' ) with the critical value being 2400 - 2500 or higher. Sonic or supersonic velocity was not a sufficient criterion. The tuyere design was a parallel tubular duct of moderate aspect ratio CAR) i.e. the ratio of length to diameter ranging from about 22 to 36 in the experimental furnace.Farmer et al[4] stated their their aim ""to develop a unifying explanation and procedure for the proper design of tuyeres"" but disagreed with Sharma's jet Froude number criterion. Recalculating Sharma's data they proposed instead a fully expanded Mach number of 1.75 with an initial expansion angle of ten degrees as the lower bounds of flow to meet the design requirement. They experimented with tuyeres in a water model using tubular, annular and convergent-divergent nozzles. The aspect ratio of the parallel duct tuyeres was from 533 to 762 using diameters of 1.4, 1.7 and 2.0 mm C the diameters being of tubes to be used full scale). Subsequently these results were applied to a prototype tuyere using a diameter of 1.7 mm with beneficial results in practice. This tuyere had an aspect ratio of 1067."

Jan 1, 1996

By J. C. Emerick

Preliminary investigations have shown that wetland-based treatment systems can be an effective and relatively inexpensive control strategy for mine drainage pollution in eastern coal mining regions. This strategy also has potential for western mining regions, although too few systems have been installed in the west to permit general evaluation of the concept for western climates. The construction of prototype systems is encouraged for some situations. Wet-land environments have the capability of removing metals by natural geochemical and biological processes, including precipitation, filtration, ion absorption, and biological uptake and accumulation. Data presented for natural wetlands receiving mine drainage show removal of iron and other metals, and high accumulation of metals in soils and plants.

Jan 1, 1988