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By Ihsan Berk Tulu, Deniz Tuncay, DYKE MARK ALEXANDER VAN, Ted M. Klemetti

Bleeder entries are critically important to longwall mining for the moving of supplies and miners as well as the dilution of mine air contaminants and must stay open for many years. In this study, standing supports in moderate cover bleeder entries were observed, numerically modeled and instrumented by researchers at the U.S. National Institute for Occupational Safety and Health (NIOSH). The measurements of the installed borehole pressure cells (BPCs), standing support load cells and convergence meters, and roof extensometers are presented in addition to the numerical modeling results and visual observations made by the NIOSH researchers in the bleeder entries. The results include the effects of multiple panels being extracted in close proximity to the instrumented site as well as over one and a half years of aging. As expected, standing supports closer to the longwall gob showed the greatest load and convergence. The roof sag appeared generally independent of the proximity to the longwall gob. The BPC readings were driven by both the proximity to the gob and the depth into the pillar. The results of this study demonstrated that the entry roof can respond independently of the pillar and standing support loading. In addition, the rear abutment stress experienced by this bleeder entry design was minimal. The closer the mine development, pillar or supports are to the gob, the greater the applied load due to rear abutment stress.

By W Schauenburg

The increasing problems associated with the disposal of waste and the potential for use of by-products as underground filling material is a subject which is relevant not only to the coal-mining industry. The progressive scarcity of surface disposal facilities for by-products and waste has now become a problem in all sectors - not only for the mining industry. The considerable capacity offered by underground cavities which exists in various mining branches present an extremely promising potential in this context. The backfill process for coal mining developed by DMT in co-operation with Ruhrkohle AG make use of the cavities which are offered by the extraction of coal. It consists of several stages: The fine-grained by-products, such as sludge, filter cakes, fine refuse, ash and flue-gas cleaning residues are processed on the basis of specified formulations in metering, blending and pump facilities on the surface to produce pumpable pastes with precisely defined flow characteristics. On Walsum Colliery of Ruhrkohle AG up to 200 m3/h stowing paste is conveyed into the mine in pipes with diameter of 200 mm (8"). The delivery pressure of the pump operating on surface in conjunction with the hydrostatic pressure of the shaft pipe - amounting in total to as much as 25 MPa - makes it possible to convey the stowing material for a distance 12000 m underground up to the workings without any need for additional booster pumps. Via a pipe installed in the face, the paste is pressurised into the cavities in the specially fragmented rock in the mined-out zone well behind the support. Consistent use of stowage of caved-in goafs makes it possible to reduce surface settlement above the workings. Fires in the stowed rock are either smothered or completely prevented thanks to the exceptional air-tightness in the caved goaf and the cooling effects of the slurry stowage. The reduced danger of fire, the preventation of air-leakage and the positive effects on gas emission from the coal improve safety in the workings.

Jan 1, 1998

By Oliver Bowles

The United States Bureau of Mines has within its ranks a group of engi- neers who are engaged in working out quarry problems, the solution of which will be of general benefit to the industries involved. The problems undertaken are approached in a systematic and thorough manner, all the evidence for and against any proposed change or new development being collected as carefully as an attor- ney would prepare his data on an important case. Unlike the attorney, however, the Bureau engineer does not take sides; his judgment is based entirely and in- partially on the array of facts presented. In order to gain the desired infor- mation he visits many plants, consults with the leaders in the industry, works out experiments in his laboratory, and supplements this information with a stu- dy of all available literature already published on the subject in any part of the world. As an engineer who has for eight years conducted such inquiries in the stone industry, I propose to discuss the Bureau of Mines viewpoint; and it may be of interest to consider with me in a brief and general way the engineer's method of looking at quarry problems, and some of the results attained through past and present labors. While the Bureau has conducted no investigation directly for the crushed- st one industries, two years of investigative work at cement-plant quarries, and work now being conducted at lire-plant quarries, has a very direct bearing on the problems of the crushed-stone industry, since stripping, drilling, blasting, loading, and transportation are similar in many respects in all stone quarries. The results of cement-plant quarry investigations are to be found in Bureau of Mines Bulletin #160. (b) Two short papers on lime-plant quarry problems have been issued in mimeographed form as Serial #01 (c) and Serial 3 (d).

Jan 1, 1923

By J Meinhart, J Rodler, I Katolicky

The ever increasing number of vehicles is leading to slow-moving and even stationary traffic sitting longer in traffic jams over extensive city areas. This traffic situation causes a sharp increase in pollutant emissions from vehicles, and high levels of pollution usually result throughout the built-up area. Reducing the pollution level by using traffic routing measures to speed up the flow of traffic in the existing street network is only possible in exceptional cases.In many cases the only option for achieving a significant improvement in traffic conditions is to shift the traffic underground using a road tunnel or underpass. Such tunnel routes suck off the traffic from large sections of the city, thereby easing the overall traffic flow. Thus on the one hand it produces a sharp reduction in pollution levels in the area of the tunnel route, but on the other hand it can result in locally increased exhaust pollution levels from longer tunnel systems that require mechanical ventilation. The air extracted by the ventilation system is blown out into the atmosphere either directly through the tunnel portal, or via a venting tower. Pollution can therefore occur in the area surrounding such exhaust air outlets.Thus if a tunnel is planned in a city, then closer investigation is required of both aspects: the reduction in pollution in the area of the tunnel route thanks to relocating the traffic and easing congestion, and the increased short-range pollution around the tunnel portals (shafts).

Jan 1, 1999

By Frances Badelow

This paper describes a design process for piled raft foundations supporting high-rise buildings. The design process comprises an initial stage of geotechnical site characterization using the results of investigation boreholes to prepare a subsurface model and derive geotechnical parameters for raft and pile design from empirical correlations. Following this a preliminary analysis is undertaken using a combination of elastic theory and allowances for non linear behaviour of the piled raft system to assess the viability of such a foundation system and any potential advantages of a piled raft over conventional fully piled foundation systems. Finally, a detailed analysis is undertaken using the GARP8 computer program. Case studies where this design process has been successfully used to design a more efficient piled raft system that has resulted in significant cost and time savings compared to conventional bored pile foundation options are also described.

Jan 1, 2006

By Guilliaem Aertsen

THE derivation of the word tire (or tyre, as it is spelled in England) is obscure. Some dictionaries suggest that it is the aphetic form for "attire, covering," so called as being the outside covering or band of a wheel; also as a corruption of "tier," the band which holds, or "ties," the rest of the wheel together. One dictionary states: "The supposed derivation of the word is that bands were first used on wheels in the City of Tyre, Syria. " In the infancy of railroads, the tracks consisted of flat baits of iron, spiked or bolted to the upper surfaces of longitudinal timbers, which; in turn, rested upon masonry foundations. Stone blocks installed for this purpose on the old Germantown & Norristown Railroad, now the Chestnut Hill branch of the Philadelphia & Reading Railway, were to be seen for many years on the right-of-way, north of what is now. Wayne Junc-tion, Philadelphia, Pa. The "cornerstone" of the Baltimore & Ohio Railroad was laid Apr. 4, 1828, and the first locomotive in America was built by Peter Cooper at the St. Clair Works, Baltimore, Md., in 1829 "to demonstrate its adaptability to a curved road." It is believed that the first successful locomotive was built in Philadelphia by Tyler & Baldwin in 1832 for the Germantown & Norristown Railroad. Rufus Tyler-and Matthias Baldwin were brothers-in-law; the latter's name will he identified with American locomotives until locomotives are forgotten. The Wheels on these first locomotives, designed to run on this primitive rail, were shod with plain iron bands, bent and welded. The flanges consisted. of separate iron bands, bent sidewise, welded, and, bolted to the sides of the wooden follies, or rings. Before many years had elapsed the tires were fabricated of iron bands, rolled in one, piece with the flange projection on the side. The tire for each wheel was bent and welded and subsequently attached to the wheel center by shrinkage, bolts, rivets and various mechanical devices.

Jan 1, 1917

By C. Newman, R. C. Ray

Originated and developed in the civil tunneling industry, the Ground Reaction Curve (GRC) has provided a robust methodology for evaluating and designing ground support in both tunnels and underground mining scenarios. This paper presents a preliminary assessment in the utilization of the GRC concept for the evaluation and design of the pillar-support system with respect to overburden stress and displacement. This initial assessment will be based on and backed by past research on this topic. Underground mine instrumentation is planned for a longwall mine in the Appalachian coal field based on the research and findings in this paper to support the postulated hypothesis. INTRODUCTION Since the early 1970’s, the mining industry has evaluated the structural stability of a pillar by dividing an approximated pillar load by an approximated pillar strength. While this design methodology has served the industry well in the past, as modern mining operations continue to develop in more complex geological and geometric conditions coupled with market economics, industry professionals are in dire need of a modified stability assessment approach which considers both the stress condition and material displacements. Within the civil tunneling industry, the GRC approach has been successfully utilized in designing underground support measures that enhance the stability of an underground excavation. Through the incorporation of current industry knowledge and understanding of ground and support behaviors this paper looks to investigate into preliminary assessment for the development of a Modified Support Response Method (MSRM) to further improve the analysis of local and global underground stability. CURRENT PILLAR DESIGN METHODS AND THEIR LIMITATIONS Globally, multiple pillar design methods have been utilized in the design of underground excavations. Each of these methods approaches the calculation of pillar stability a little differently with respect to material properties, underground geometries and stress conditions. Analytical solutions can be used to determine the strength of homogeneous materials like concrete, but not in case of non-homogeneous and non-isotropic mineral deposits in a mine. These equations are often derived using empirical methods. Pillar strength is defined as the maximum resistance of a pillar to axial loading (Brady & Brown, 1985). The strength of mine pillars is typically estimated through indirect methods. In the past, researchers have correlated the strength of a given size and width of a rock specimen to the strength of a mine pillar. The first study on the effect of geometry on rock strength was done by (Bauschiger, 1876) on Swiss sandstone samples. Since then several empirical equations to determine pillar strength had been published by many researchers like (Bunting, 1911), (Griffith & Conner, 1912), (Greenwald, Howarth, & Hartmann, 1939), (Holland & Gaddy, 1957), (Evana, Pomeroy, & Berenbaum, 1961) and (Holland C. , 1964).

Jan 1, 2019

By R. Laucournet, E. Billy, M. Joulié

Today Li-ion batteries are considered as one of the most attractive available energy storage solutions. However in order to overcome environmental, legislative and economic issues, the management of used batteries has to be considered and mainly the recycling. The present paper deals with the recycling of used Li-ion batteries and the recovery of high value metals from active materials of electrodes. Lithium nickel cobalt aluminum oxide (NCA) and lithium manganese nickel magnesium oxide (LMNM) cathodes, which contain most of valuable elements typically used in the composition of active materials for Li-ion batteries are investigated by a hydrometallurgy route. The process is divided into two steps: the materials leaching and the elements recovery by a selective chemical separation. Some experimental parameters (acid nature, concentration, time and temperature) are studied to determine the most efficient conditions of dissolution. Then, the valuable elements such as nickel, cobalt and manganese are selectively recovered with a high efficiency close to 100 % and with a high purity by precipitation. By this study, an adaptable hydrometallurgy process can be defined according to the composition of Li-ion batteries to recycle.

Jan 1, 2014

By E. J. Gleim

A list of permissible mine equipment, tested and approved previous to January 1, 1942, was published In Bureau of Mines Information Circular 7207.3/ The present list covers additional equipment approved during the calendar year 1942. The items have been numbered to indicate the order in which each type of machine or device was approved in its particular classification. Thus, Information Circular 7207 gives four air compressors on the Bureau's active list, and the present circular gives the fifth to be approved. Items 90 and 94 under Loading; Machines land Conveyors also appear in Information Circular 7207. These numbers are repeated hero to show that approval was granted during 1942 for additional voltages on machines previously listed 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 which may become so, is earnestly recommended in the interests of safety. This circular is published so that the industry may be kept informed as to the many types of machines, devices, and lamps that arc available for reducing explosion and other hazards incidental to coal mining. The present paper and Information Circular 7207 together give the complete list of all available permissible .Mine equipment.

Jan 1, 1943

By Stephen Mansfield

In metalliferous mining operations, subdrill is that portion of the blast hole that is drilled below the target grade elevation, and in most cases loaded with explosives. Its primary aim is to enable efficient excavation down to the target floor level. Subdrill is often described as being expensive and that excessive subdrill should be avoided, as it can result in damage to the subsequent floor, lead to difficult drilling conditions and higher vibration levels. As a result, many operations aim to apply the bare minimum amount of subdrill in order to excavate to the target floor. At a large open cut copper operation, challenging geological structure resulted in slabby and blocky fragmentation in the stemming region, resulting in poor crusher throughput due to bridging. To overcome the poor fragmentation in the top of the bench, longer than conventional subdrill was used to precondition the top third of the bench. The technique significantly improved the run of mine fragmentation and resulted in feed to the in-pit crushers that is more consistent, which produced less crusher downtime due to bridging. A new method of quantifying the energy in a blast has been created. Termed the linear powder factor, or energy factor, the calculation considers the energy contributed by the subdrill of the upper bench and its impact on the energy in the lower bench. The technique enables blast designs to be optimised to deliver finer fragmentation and more consistent blast outcomes. To support the layer of preconditioned rock at the top of the bench, an innovative new device was developed. The device is inserted into the drill collar immediately after drilling and remains in position throughout the subsequent steps of hole depth measurement, priming, loading and removed prior to stemming. The device not only supports the broken rock at the top of the bench, but also minimises the amount of drill cuttings that fall back into the hole. Furthermore, the device helps protect the hole from damage by external factors such as weather events, drill tracks, vehicle tyres and movement around the collar during measurement and loading of the blast hole.

By John Meuth, Brandon Fryman, P. E. Hoffman, Joshua Ph. D., P. E. Calnan, Josh Ph. D.

Quantitative Risk Assessment (QRA) can be specifically tailored for use by the commercial explosives industry to calculate risk to employees and the public from commercial explosives facilities and operations. This methodology has several advantages over the American Table of Distances (ATD) which is solely a Quantity Distance (Q/D) analysis. While the ATD has remained essentially the same for 100 years, the safety of commercial explosives in storage has increased immensely. However, the concepts behind QRA calculations are not as intuitive and even at the end of the calculations the values of risk must be compared to something. A few regimes for assessing an acceptable level of risk are discussed in this paper. Risk levels for various United States Federal entities and international agencies are highlighted and suggestions for acceptable risk criteria for individuals and groups are provided. Referencing risk levels from normal daily activities is also done in this paper to make relative the accepted risk criteria. This paper presents some relevant individual risks for everyday activities and some scenarios for group risk for comparison. Individual risk is a straightforward concept however group risk is more complicated. This paper aims to clarify these concepts and provide means to communicate them to the public.

Jan 1, 2019

By Marcos de Oliveira Fonseca

O crescente volume de dados gerados pelos sistemas computacionais tem estimulado o uso cada vez maior das técnicas de Data Analytics. Tais técnicas suportam a transformação dos dados em informações úteis para tomada de decisão nas diversas áreas de negócio. Na indústria em geral essa situação não é diferente, graças também ao uso cada vez maior de sistemas de automação e informática industrial. Esses sistemas coletam e disponibilizam milhares de dados do processo numa alta taxa de aquisição, o que normalmente representa um altíssimo volume de dados, muitas vezes chamado de Big Data. O presente trabalho mostra como essas técnicas podem ser aplicadas para maior conhecimento do comportamento e melhoria do desempenho de processos industriais, usando uma abordagem prática de inteligência de negócio que explora as características dos sistemas de automação e informação industrial.

Jul 30, 2018

By Julián Pérez Falcón

El mineral que se procesa en la planta concentradora de Mesapata-Cátac de la Compañía Minera Toma la mano S.A. presenta comportamientos complejos puesto que el mineral es oxidado y polimetálico. En ese sentido, el presente texto busca recuperar los minerales oxidados polimetálicos complejos a través de la tecnología limpia de dicha empresa que consiste en eliminar reactivos nocivos al medio ambiente y sustituir o reducir a otros por reactivos orgánicos.

Aug 1, 2012

By V Novoselov, R Sabirov

Flotation processing technology of water-soluble minerals has made it possible to realise, since the 1960s, the wide scale industrial processing of potash and potassium-magnesium ores (about 200 million tonnes per year) as well as to create the multi-tonnage worldwide production of sylvite (KCl) for industrial and agricultural application. In this paper the particularities of the effect of reagents (blinders, collectors and frothers) during cation flotation in saturated saline solutions are outlined. New reagent modes for activating the effects of alkylamines during the flotation of KCl and the perfecting of technological flow sheets for processing potassium ore have been developed. The results of research on the reverse flotation of carnallite ore, with the help of alkylmorpholine û a new developing technology for benefication carnallite as raw material for the production of metal magnesium and fertilisers are listed. Examples are given of the industrial applications of processed reagent modes at potash flotation factories in Russia.

Jan 1, 2005

By R. Heikkilä

In this paper the utilisation of building information models (BIM) and construction automation on building sites is discussed. A lot of research has been carried out to develop new applications for using BIM to assist construction site planning, different operations and logistics. The methods of production control and management on site utilize BIM together with machine control and navigation systems. In Finland machine control systems and the automation of construction equipment is widely used in infrastructure construction. Recently similar methods have been introduced also in building construction. This paper describes some latest Finnish examples where BIM-software is used for the planning, execution and control of building construction operations. University of Oulu has studied methods and technologies to capitalize BIM-models. The research has been mainly in infrastructure construction but the activities have recently been extended to building construction. In this paper a BIM-based tower crane operation and control system is discussed as a case study. The aim of this study was to highlight the potential areas were automation can increase the crane productivity and improve site operations and logistics. The construction site managers and tower crane operators interviewed in this study were experienced in using BIM-models on site.

Aug 1, 2013

By Christodoulos Xiouris, Ali Reza, James Karnesky

A rocket parachute signal flare is often used to signal a maritime emergency. In the general operation of these devices, a solid rocket motor propels a metal body to an altitude of approximately 1000 ft(305m).At the end of the rocket motor, a propelling charge drives a signal flare and parachute out of the metal body and ignites the flare, which then burns for approximately 40 seconds as it falls to earth. In this paper, we describe an engineering investigation of an accidental ignition of a rocket parachute signal flare, which caused injury to the user. The components of the flare involved in the accident were inspected via x-ray and microscopic imaging techniques, and compared with those of unfired flares recovered from the same vessel. Chemical analysis of residue on recovered components from the accident flare was also performed. These comparisons were used to determine the likelihood that the actuation mechanism had been deliberately manipulated. In the subject model of the flare, ignition of the rocket motor is accomplished through a percussion cap which is struck by a firing pin. Prior to activation, the firing pin holds down a pre-compressed spring. We present a comparison of the ignition system of the incident flare with those of other rocket parachute flares, which do not incorporate any stored mechanical energy.

By D. M. Ramsey

HIGH-INTENSITY magnetic separation as now practised in the commercial treatment of a large variety of industrial minerals is a com-paratively recent development, having had its practical beginning about ten years ago when it became necessary to devise more effective methods for the purification of the electric furnace abrasives and refractories-silicon carbide and fused aluminium oxide. The fundamentals of magnetic separation are, of course, very well under-stood; bur while very, very old in principle, the process has, in recent years, been developed to a point of far greater usefulness than heretofore. In fact, until the development of the high-intensity process,. magnetic separation was limited largely to the removal of tramp iron? with magnetic pulleys and the removal of the very highly magnetic portions of industrial minerals by means of horizontal conveyor-belt-type separators. All magnetic separation processes depend for their success on the fact that various materials are kinetically influenced to a greater or lesser degree by the force that we speak of as 'magnetism'. We have now come to regard 'magnetic separation' and 'high-intensity magnetic separation' as two different and distinct methods. However, both depend upon the reaction of a particle when placed in a magnetic field. The common types of magnetic separators quite generally operate on the principle that a magnetic particle can be lifted by a powerful magnetic force from a stream of material moving on a belt or other type of conveyor. The application of the force removing magnetic material by this scheme is directly opposed to the force of gravity and is, therefore, limited to sub-stances of a relatively high order of magnetic susceptibility, such as metallic iron and magnetite. Until a few years ago, one very important principle was almost entirely overlooked. Practically every substance is susceptible to some extent, at least, to magnetic attraction, and by the application of a magnetic force great enough, and properly applied, separations of materials heretofore considered 'non-magnetic' can be accomplished.

Jan 1, 1937

G. SHERBURNE ROGERS,* Washington, D. C. (written discussion?).- We are indebted to Captain Lucas for an interesting contribution to the literature of the salt-dome oil fields, and especially for his suggestion that a more aggressive method -of prospecting be adopted. The occasional discovery of new fields on, the Gulf Coast is in itself sufficient to show that the oil possibilities of the region are by no means exhausted, and those who have studied the area most thoroughly are the most optimistic regarding its future. Nevertheless, the search for new fields, according to present methods, involves the expenditure of great sums of money annually, for the proportion of dry holes to producing wells drilled yearly in the Gulf Coast region is much' greater than in most areas, even if all the wells drilled in what is commonly regarded as proved territory are included. Not only are the present methods of locating new domes very uncertain, but when a dome is discovered there is no assurance that it will be oil-bearing; or, if so, whether the oil occurs in the cap-rock, in the sands above it, or in some small isolated lens of sand far down on the flanks of the salt mass. As Captain Lucas points out, about all we positively know is that the domes are there and that some of them are oil-bearing; their origin is a matter of controversy and the original source of the oil is conjectural. Under these conditions, it is not surprising that the search for oil is conducted more or less blindly and that dry holes are common. Many wells are drilled each year in an endeavor to find oil at depths of 2000 or 3000 ft. (609 to 914 m.) or less, in locations which most geologists would condemn without hesitation. As Captain Lucas suggests, the money spent in this way might be used to far better advantage in, drilling one deep well in a carefully selected locality. Opinions may differ as to whether such a, well would find oil, and many geologists will probably believe that the chances are against it, yet all will agree that the boring, whether it finds oil or not, will probably throw light on the origin of the domes and on the source and mode of accumulation of the oil, and will therefore be of great interest, not only to the scientist, but to the oil operator.

Jan 10, 1918

By Ralph W. Barbaro

In many parts of the country, electric utilities use spot market coal to make up the difference between the amount of contract coal and the total amount burned. The utilities involved will normally have a structured contract for those companies supplying that spot coal. These contracts will often involve a pricing schedule with bonuses or penalties for coal above or below the specified coal quality goals. Normally, penalties will be assessed on the sulfur, ash, and other coal quality variables. This paper deals with some aspects of the pricing schedule of one of the eastern utilities that buys coal on the spot market. This utility has a number of plants that a supplier can attempt to supply through bidding procedures. The existence of the pricing schedule gives the supplier a number of different options. To the single-mine producer, options are available to send the coal to any demand site and to clean all, part, or none of the coal. In other words, he can ship to a number of different sites and can send different coal qualities to each site depending upon the level of preparation. In addition, the options to deliver blended coal to any given site will provide an additional level of complexity to the problem.

Jan 1, 1983

By Maycon Athayde

A Samarco Mineração utiliza combustível gasoso para geração de energia térmica para o endurecimento pelotas de minério de ferro. O balanceamento térmico do forno ocorre através do controle das malhas de instrumentação que são compostas por válvulas de controle, sensores de temperatura, queimadores e sistema de suprimento de Gás Natural Industrial (GNI) para a combustão. A combustão é realizada por meio de queimadores, que são alimentados por uma mistura gasosa de GNI e Ar Atmosférico, ambos a temperatura ambiente. A função do GNI é fornecer a sua máxima capacidade energética para a produção de calor. Já o Ar atmosférico é resfriar o queimador, e estabilizar a chama dentro da câmara e ar primário de combustão. No entanto excesso de ar é fator determinante para eficiência de combustão, pois controla os produtos da queima, entre eles a temperatura. Um grande excesso de ar é indesejável, pois reduz a temperatura da chama, e aumenta as perdas de calor devido à entalpia dos gases.

Aug 1, 2018