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By John C. Draper

Little precise information is available on the effect of mining on the surface topography. It is often assumed that after mining the surface will simply sink. This is not an infallible conclusion as is well illustrated in two of the three examples herein. This paper describes the results of an attempt to precisely measure the surface movement in the area around coal pillars left in place for three oil wells in a completely mined and caved area at the Harwick Mine of the Duquesne Light Company. The dates when the various measurements were made are shown on the data sheets and indicate the rate of surface movement. These oil wells are identified as wells Nos. 2, 3, and 6. This mine property is located on the north side of the Allegheny River at Cheswick, Pennsylvania, and extends in a northerly and westerly direction about five miles. The three well pillars are situated on the westerly side of the Bessemer and Lake Erie Railroad some 2,000 feet from Rural Ridge, Pennsylvania (Fig, 1).

Jan 1, 1964

By Per Svedensten

One of the most significant behaviour of a crushing plant is the constant variation in the process. The variation is caused by two major effects. The first and constantly changing is the rock material properties. During operation rock material with different strength and particle size distribution is fed to the plant which makes the performance of the equipment to vary. The second and more slowly changing variation is caused by wear on the processing equipment. These effects must be predicted in order to be able to optimise a crushing plant. This paper demonstrates how Monte Carlo simulation can be utilised to study and operate crush-ing plants. By introducing Monte Carlo simulation the varying process can be study and also optimised. To maintain the optimised process performance supervision is needed. This paper demonstrates how results from the Monte Carlo simulation can be utilised for process supervision. Charts for process measurements can for example be derived. These can then be used to guide decision making and understand how the variation and performance of the plant changes over time.

Jan 1, 2014

By Robert F. Mehl

EXTENSION of physical and chemical methods of research in the study of metallic behavior continues rapidly, particularly in the correlation of behavior with crystal structure, and in the analysis of elastic and plastic properties. The growth of the science of metals during 1933 calls for special comment; the need for special reviews and for textbooks and monographs is now acute, as might he supposed from the number of references appended to this article, a list which is much abbreviated.

Jan 1, 1934

By Bjorn Olsson

"Heavy impact. High frequency hammering. Extreme abrasion. Building on the experience of owning and operating its own mines, Ovako has developed a deep knowledge of how vital the right steel properties are in withstanding the extreme loads encountered in every part of the drill string. That is why Ovako’s product development process is focused on understanding the specific load cases and manufacturing operations associated with rock tools.The punishing conditions of percussive drilling can push the limits of most materials. And heavy mechanical loads are only the beginning. Highimpact energies at high frequency are a major source of fatigue. High temperatures result from impact energy losses. And abrasive, erosive and adhesive wear are constant risks. Handling any of these varying demands at a single point along the drill string is difficult enough — which makes optimizing for the entire drilling system an extremely complex challenge. Engineering for specific loadsOvako has specialized over many decades in analyzing the dominant loads for each of the parts and components used in rock tools, and testing for individual applications in its laboratories. The most critical fatigue properties are controlled through the steel metallurgy, and supported by performance measurements through extensive rotating bending fatigue (RBF) testing, along with special methods that combine impact load with various wear loads. The result is a fit-for-purpose steel with tightly controlled performance properties, making it possible for customers to precalculate the expected life time of their components for highly automated and repetitive processes Tailoring steels for the processing route.The same levels of control and predictability must be carried through to the customer’s own manufacturing processes. By ensuring minimal variations in chemical composition, everything from heat treatment and welding to automated machining can be carried out with high consistency. With precisely controlled material properties based on an existing processing route and exact load case, customers are able to minimize their total tool production costs while ensuring optimal performance for their end products. Development of Hybrid SteelBuilding on this experience in the mining industry, Ovako has developed a new steel family, known as Hybrid Steel, designed to meet the demands of high-stress, elevatedtemperature applications where mechanical and fatigue strength are critical. Traditionally, steels for these applications are produced by expensive small-batch processes. Hybrid Steel, however, enables high volume production at a competitive cost.The world of steel has traditionally been divided into clearly separated categories of tool steel, stainless steel and lower alloy engineering steel. Hybrid Steel is now challenging that division, offering attractive properties from all three categories."

Jan 12, 2017

By R. L. Loofbourow

Most wet mines face unquantified water costs as well as the obvious wing costs. Both kinds of cost are multiplied by work at greater depth and by higher unit prices. This intensified challenge merits renewed or perhaps altogether new response. Any practicable way to reduce inflow tackles both obvious and unquantified costs. Ten groups of possible ways to do it are cited. Most have been demonstrated. Two are known from work other than mining. Surely new means can be found. Here are opportunities for operators of wet mines!

Jan 1, 1980

By Lucien Eaton

The mining methods described in this paper are those used in a large mine producing hard specular ore on the Marquette Range in the Upper Peninsula of Michigan. Although the conditions of mining are unique in this district, they are similar to those in many other districts, and information in regard to the methods used and the results obtained should be of interest. The methods now used are an outgrowth of those of former years which have been adapted to conform with improvements in mechanical appliances, changes in the wage scale and labor supply, and the' selling price of the product. The mine is situated' at Ishpeming, in the Upper Peninsula of Michigan, 16 miles west of Marquette, its shipping port on Lake Superior.

Jan 1, 1929

By Theo Lehner

The Rönnskär smelter has wide experience in the field of recycling of non-ferrous metals. Today, smelting and refining from primary and secondary raw materials are integrated in a complex flow sheet. Boliden operates a lead flash smelter, a lead refinery, a copper smelter and refinery, a sulphuric acid and sulphur dioxide plant, a slag fuming plant and precious metal plant at its Rönnskär smelter in the North of Sweden. The Business Area Smelter Operations also incorporates Boliden Bergsöe, Sweden's lead-acid battery recycler, and Norzink, Norway, where recycled zinc accounts for more than 20% of it's production. Raw materials for the Rönnskär smelter include concentrates, ashes, slags, metallic scrap, electronic scrap and electric arc furnace (EAF) steel-making dust. This paper briefly describes current operations and illustrates current measures to improve productivity. Limits to recycling as experienced by a non-ferrous smelter are, illustrated. The deportment of critical elements contained in raw materials is also discussed.

Jan 1, 1998

By Miguel Aucapoma, Juan Mori, Pablo Zevallos

El sistema preventivo de desprendimiento de rocas es un prototipo de un equipamiento instrumentado digital cuya función es monitorear la condición de los techos de los socavones para evitar que se produzcan accidentes por desprendimiento de rocas producidos por debilitamiento de estructuras que sostienen los techos de los socavones debido al corrimiento de las estructuras del macizo rocoso, donde básicamente el sistema informa mediante la activación de alarmas preconfiguradas al interior de mina. El propósito de estas alarmas es prevenir y evacuar al personal de las zonas que detectan el desprendimiento de rocas. El prototipo fue diseñado como una propuesta de solución tecnológica al problema de accidentes por desprendimiento de rocas en las operaciones mineras en Perú, las cuales sumaron 297 víctimas, que representaron el 25% del total de accidentes mortales entre los años 2000 y 2018.

Sep 20, 2019

By F. H. Nehl

Ion elutriation was used to extract silver cyanide complexes and free cyanide from aqueous streams containing up to 10 ppm silver and 5 ppm free cyanide. Screening tests selected nine of 350 different surfactants for further, larger scale experiments. The screening procedure used 0.1 g of each of the surfactants in 300 mL of synthetic wastewater. Air was sparged into the test cell at 50 cc/min. The foam was refluxed during the tests and was not sampled. Samples of the solution were taken at specified intervals and analyzed by wet chemical methods for free cyanide and by atomic absorption for silver content. The most effective surfactants lowered the silver and free cyanide concentrations to less than 0.5 ppm in 1 h or less. These surfactants were quaternary amine salts with one long chain (C12-C18) organic group and three methyl groups. Experiments using 3 L batches of wastewater or an ion elutriation cell continuously fed with solution draining from an inactive heap leach operation confirmed the results from the screening tests.

Jan 1, 2010

By Enrique Lastres Berninson

La presente investigación refiere la problemática que ocurre en el incumplimiento de los roles del trabajador y el empresario minero. Para ello, se describe las normas dictadas en el último decenio, se analiza los defectos que ha producido la aplicación de normas en el sector minero, así como se visualiza las medidas de perfeccionamiento y la corrección del sistema imperante en la actividad de las empresas mineras.

Nov 20, 1978

By José de Camargo

Em janeiro de 2016 a Russula foi contratada pela Dojran Steel (Sidenor) para a reformulação de sua planta de Nikolic / Macedônia. O fornecimento incluiu um novo laminador de barras e perfis com capacidade para atingir 350.000 toneladas por ano, composto de equipamento mecânico, sistema de automação, bem como todo o suporte técnico necessário para a Dojran Steel expandir sua antiga gama de produtos e melhorar sua qualidade de produto acabado. Ao final da reformulação, executada em várias fases, o novo laminador adquiriu capacidade para produzir toda gama de produtos desejada: - Redondos de 8 a 40 mm, - Barras chatas de 16 x 4 a 140 x 20mm, - Quadrados de 8 a 40 mm, - Cantoneiras de abas iguais de 20 x 20 x 2,5 a 120 x 120 x 12mm,- Cantoneiras de abas desiguais de 30 x 20 x 3 a 120 x 80 x 10,- Perfil U (UPN) com altura de 30 a 140 mm,- Perfil I (IPE) de 80 a 120 mm e - Perfil T de 20 a 50 mm.

Oct 30, 2017

By E. G. Davis

The Bureau of Mines studied tailings samples from 11 large-scale western copper operations to determine the potential for recovery of rutile and other critical and strategic minerals. Up to 15 pounds per short ton (lb/st) Ti02 was found ion these samples; however, only 9 to 44 pct of the Ti02 was liberated rutile. For one sample, gravity preconcentra-tion, grinding, and flotation recovered 34 pct of the Ti02 in a 54.8-pct-Ti02 concentrate. Over 0.38 Ib/st W was found in some of the tailings sampleso Scheelite was identified as the major W mineral. Nine of the eleven samples contained about 0.02 to 0.18 Ib/st Co. Pyrite was the principal Co-bearing sulfide mineral, with Co contained in about one-fifth of the pyrite grains. Up to 30 pct of the Co was concentrated in a bulk sulfide flotation concentrate.

Jan 1, 1988

By Zhanjun Wang, Mei Zhang, Zuotai Zhang, Min Guo

In this study, the viscous flow and crystallization behavior of CaO–SiO2–MgO–Al2O3–FetO–P2O5–TiO2 steelmaking slags have been investigated over a wide range of temperatures. The results indicated that the viscosity of the slags slightly decreased with increasing TiO2 content. The constructed non-isothermal continuous cooling transformation (CCT) diagrams revealed that the addition of TiO2 lowered the crystallization temperatures. This can mainly be ascribed that the addition of TiO2 promotes the formation of [TiO6]-octahedra units, thereby MgFe2O4–Mg2TiO4 solid solution is formed. Moreover, the decreasing viscosity has a significant effect on the diffusion of ion units, such as Ca2+ and [TiO4]-tetrahedra, from bulk melts to crystal-melt interface. The crystallization of CaTiO3 and CaSiTiO5 was therefore accelerated, which can improve the phosphorus content in P-enriched phase.

Mar 1, 2017

By John Garcia

THE presence of carbon de terre along the banks of the Illinois river was noted by the members of the Joliet and Marquette expeditions in 1673, and that may be referred to as the birthday of coal in the Middle West. The march of progress in the majority of indus-tries radiating from Chicago-one of the phenomena of history-is due in no small measure to this same carbon de terre and to the development and exploita-tion of the vast coal resources, which nature in a generous mood spread so lavishly over almost the en-tire state. The geological records indicate that coal-bearing rocks underlie three-quarters of Illinois, in-cluding 85 of the 102 counties and the entire area is estimated at from 36,000 to 42,000 square miles. Not all of the coal in this great area may be mined under the conditions existing today; producers are now taking the "cream" since industry demands the best quality and the lowest cost, thereby forcing competition among operators, which, in turn, com-pels the development of mines in those areas where the coal may be most readily .won, leaving the coal that is more difficult and expensive to mine to pos-terity. This is not such a bad arrangement, since the engineers of succeeding generations will enjoy the advantage of the experience of their ancestors, where-by they should profit and know how to mine a 2-ft. seam with as much economy and dispatch as we today work coal of thrice that thickness. During the period between 1830 and 1850, Illinois coal-mining progressed from the art of scratching along the outcrop to the development of small mines, mostly slopes, drifts and shallow shafts, but the real progress in the industry was coincident with the con-struction of railroads.

Jan 2, 1927

By Stephen J. Swan

Feed-forward control (i.e. the forward flow of information in a control system ) is a simple and flexible approach to over-all control of a ball mill-rake classifier grinding circuit. The system described here uses mill power, feed rate, mill dilution water flow rate, and classifier dilution water flow rate only, to control mill load, throughput, mill solids, and classifier solids as well as classifier overflow grind. The mill load is controlled by a simple feed-back control loop, while mill solids and overflow grind are controlled within close limits by a unique non-linear feed-forward water control system. In effect the control follows a limited mathematical model of the grinding circuit. The configuration minimizes deviations in overflow grind due to changing ore conditions, but since it is open-loop, and the model is not complete, it is affected by changes in total ball charge and liner wear. These effects are fortunately gradual, and changes in the grind can usually be kept to within ± 1% of a target continuously for several days without adjustment. Control adjustments are made with feed-back from laboratory composites. This control system has won enthusiastic operator acceptance; it is easily started up and shut down; grind-outs have been eliminated along with flotation machine flooding and mill spills. Standard measurements and components are used throughout providing a trouble-free system design at a moderate cost.

Jan 1, 1970

By Kendall Y. Onstott

The paper presents the results of a plant test using WEMCO 1 + 1 enclosed flotation machines for inert gas (nitrogen) flotation of by-product molybdenite from copper sulfide concentrate. Copper depressant consumption in the rougher flotation stage was reduced by 68% as reagent consuming oxygen was removed from the flotation air. Unlike other nitrogen flotation systems used in the industry, nitrogen is recovered above the flotation cells and from froth in tails and concentrate streams and recycled, resulting in minimal nitrogen makeup requirement.

Jan 1, 1984

By H. Leitch

In laboratory experiments, the Bureau of Mines investigated melting, quenching, and sulfuric acid leaching of alumina from mixtures of albite and anorthite, and from anorthosites containing 26 to 32 percent alumina. Variations in pouring temperature, quenching and leaching conditions, were studied with respect to the extraction of alumina and impurities. Virtually all of the alumina was dissolved by leaching melted and quenched California anorthosite in boiling 16-percent sulfuric acid solutions for 15 to 30 minutes. The leach solutions were readily separable from the solid residue by conventional thickening and filtration techniques. Only 2 to 5 grams of SiO2, Fe2O3, or CaO dissolved per 100 grams of alumina. The quantity of SiOz in solution varied inversely with the duration of the leach and with the concentration of the H2SO4 solution used. Melted and quenched Wyoming and Minnesota anorthosites with SiO2:CaO weight ratios of 4.3 and 3.2, respectively, were less amenable to sulfuric acid leaching than California anorthosite with an SiO2:CaO weight ratio of 5.3. However, excellent results were obtained on the Wyoming and Minnesota anorthosites by the addition of SiO2 to these materials before melting, in quantities sufficient to adjust the SiO2:CaO weight ratios of the furnace charges to between 4 and 6.

Jan 1, 1966

By G. R. Leverant, C. P. Sullivan

Re crystallized TD-nickel mi-2Th0,) in both coated und uncoated conditions was fatigued at 1800°F at total strain ranges varying .from 0.2 to 0.75 pct. The fatigue life of uncoated inaferal, Nf, was related to the total strain range, ?eT, by (2Nf/021AeT = 0.014. A duplex Al-Cr pack coating increased the fatigue life by about a factor of two. The cracks that led to failure in both coated and uncoated material were initiated at the outer surface, indicating that the mechanical properties of the surface layers were important in determining fatigue life. Crack propagation and subsurface crack initiation in the TD-nickel occurred preferentially at grain boundaries with cavitation at thoria particle-matrix interfaces an integral part of the grain boundary fracture process. The importance of both the grain morphology developed during thermome chanical processing of TD-nickel and the distribution of thoria particle sizes to fatigue resistance are discussed. THE fatigue properties of only a few dispersion-strengthened metals have been studied at temperatures 0.5 Tm;1,2 among these have been lead and aluminum containing oxide dispersions. TD-nickel is a material of interest for application in aircraft gas turbine engines, but little fundamental information is available on its behavior under cyclic loading conditions. In this study, the low-cycle fatigue properties of TD-nickel were determined at 1800°F with emphasis on the 101-lowing; 1) the relation of the grain morphology produced during thermomechanical processing to crack initiation and propagation; 2) the role of thoria parti-cles in the fracture process; and 3) the effect of an oxidation resistant coating on fatigue life. I) MATERIAL AND EXPERIMENTAL PROCEDURE The TD-nickel was supplied by DuPont as a 5/8-in. thick plate which had been subjected to a proprietary series of thermomechanical treatments with a final anneal at 2000°F for 1 hr in hydrogen. The composition of the material is given in Table I. At the test temperature of 1800°F, the 0.2 pct offset yield stress was 15,000 psi, and the elongation and reduction in area were 4.6 and 3.0 pct, respectively. The microstructure of this material has been previously described.&apos; Briefly, it consists of an array of lath-shaped grains, about 0.15 mm in thickness, with the long dimension of each grain parallel to the primary working direction, Fig. 1(a). The presence of very small annealing twirls, Fig. l(b ), together with the absence of extensive dislocation networks, Fig. L/C), indicated that the material was in the recrystal- Table I. Composition of TD-Nickel ThO2 2.3 vol pct C 0.0073 wt pct lex 0.01 wt pct Cr 0.01 wt pct Cu 0.004 wt pct S 0.001 wt pct Ti <0.001 wt pct Co <0.01 wt pct Ni bal lized condition. Commercial TD-nickel sheet has a similar grain size and shape, but unlike the present material is not recrystallized as evidenced by the absence of annealing twins and the presence of a well-developed dislocation substructure.4 The plate material had Young&apos;s moduli in the rolling direction of 22 x 106 psi and 13 x 106 psi at room temperature and 1800°F, respectively, indicating a texture with a strong {100}<001> component in agreement with previous observations on recrystallized TD-nickel sheet.596 The 2.3 vol pct of thoria particles were uniformly distributed although some clustering and stringering of larger particles was occasionally seen. The average diameter of the particles was 450 and the calculated mean planar center-to-center spacing was 2100Å. Two specimens were coated with a duplex A1-Cr pack coating. The coating was somewhat nonuniform from one position to another along the gage length. An area of the coating after testing is shown in Fig. 2. Electron microprobe analysis revealed the following zones in the various lettered regions indicated in Fig. 2: A) a bcc matrix of B-NiA1 with some chromium in solid solution along with a fine dispersion of a chromium-rich second phase which was probably precipitated during cooling from the test temperature to room temperature; B) fcc y&apos;-Ni,Al with some chromium in solid solution; C) porosity; D) a two-phase mixture of a chromium-rich solid solution containing nickel and aluminum and a small volume fraction of a nickel-rich solid solution having approximately the same composition as the immediately adjacent portion of region E, E) the TD-nickel substrate containing chromium in solid solution to a depth of 5 to 10 mils. As expected from the nature of the diffusion processes involved,7 the thoria particles were present only up to the layer of porosity, region C, Fig. 2. The measured thickness of the coating proper, zones A to D, after testing was 1 to 2 mils. The specimen design and testing techniques have been previously discussed.&apos; Stressing was axial and parallel to the lath-shaped grains (i.e., parallel to the rolling direction). The total strain range was controlled between zero and a maximum tensile strain varying from 0.2 to 0.75 pct. (The test at 0.2 pct total strain range was switched to load control at 1030 cycles at which point the peak tensile and compres-

Jan 1, 1970

By Marcos Danilo Monteiro

O final do século XX foi marcado por um grande avanço tecnológico em sistemas automatizados com variadas aplicações, dando destaque ao campo da robótica que desde então busca otimizar cada vez mais os processos industriais, eliminado a mão-de-obra humana em segmentos onde sua presença antes era indispensável. O aumento na qualidade do produto, a relação custo-benefício e dentre outras melhorias que a robótica trouxe a uma linha de produção industrial, justificam a procura por parte das grandes empresas em procurar investir na inserção desta tecnologia ou no melhoramento dela em sua cadeia produtiva. Este trabalho teve como principal objetivo demonstrar a aplicação da tecnologia robótica na indústria, em proporções reduzidas e fins didáticos, com a integração de um sistema de controle e automação representado pela plataforma Arduino que atua no controle de coordenadas de um braço robótico em atividades de carregamento e paletização de cargas.

Jul 30, 2018

By Jorge L. Dellepiane

"El texto describe el funcionamiento del sistema operacional de las empresas a partir de cuatro elementos del mercado: calidad, cantidad, precio y oportunidad. De acuerdo a estos requisitos, se evalúa los aspectos económicos, temporales, la calidad y habilidad para dirigir y controlar personas. Asimismo, es importante que la administración de una empresa designe funciones que establezcan una formación de políticas y control expresadaen Directivas o Instrucciones (Directorio), como de funciones ejecutivas (Gerente y Jefes) en los deberes de las políticas establecidas. En este proceso administrativo, es necesario que las actividades específicas sean combinadas dentro de un sistema integral en el que el funcionamiento de las partes se determine por la necesidad de conjunto. Es decir, que la suma de ""las partes por el todo"" se convierte en la característica principal de este sistema operacional. "

Jul 20, 1961