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By J. A. Kost

The contract objective was to evaluate the effectiveness of available dust-control technology for double-drum shearers. Eight underground surveys were conducted to evaluate drum design, drum spray nozzle locations, ranging-arm sprays, water quantity, wetting agents, and cutting techniques. The final report is made up of eight dust-control technique reports, each discussing, details of the individual mine surveys.

Jan 1, 1985

By T. Reed Scollon

Before we can attempt to answer the question of what can be expected from coal research, let us examine why research is done in other fields and what others expect for the money they spend on research and development. Up to 1900 almost all organized research was carried out at universities. Most of the support came from the university, and by present standards the amount of research was extremely small. The motivation for university research was basically discovery of new phenomena, with the objective of advancing knowledge. Side by, side with this organized effort was that of individual inventors who were primarily responsible for applying this new-found knowledge to useful purposes. During this period inventors were rarely supported by anyone, and experimentation was carried out either in their spare time or at the expense of earning a living. Men like Edison, I believe, were the first to demonstrate on a large scale that one could systematically apply newly discovered scientific principles to inventions that would serve useful purposes and would return a profit to those engaged in the effort. The tremendous expansion in research therefore began with the realization and demonstration that the scientific discovered could be applied in such a way as to return a' handsome profit to those who invested in it. The motivation of many of the research personnel however, remained the satisfaction associated with new discoveries, The money to support their efforts came from those interested in a return on their investments. Since the First World War and a rapidly accelerating rate since the Second World War another important motive for supporting research has appeared--the needs associated with national defense; this type of research has been supported almost exclusively by the Government.

Jan 1, 1959

By J. Herbst, J. Groppo, A. Noble, R. Q. Honaker

"Coal and coal byproducts produced annually contain enough rare earth elements (REEs) to meet current U.S. demand. The REEs exist in the form of minerals, ion-exchanged elements associated with clays and chemically bonded elements within the organic coal matrix. Researchers at three universities have collaborated to evaluate the effectiveness of existing physical and chemical concentration processes for the recovery of the REEs. The efforts have found that physical separation processes can increase the total REE content in the thickener underflow material collected from a Central Appalachian coal cleaning facility from around 300 ppm to values greater than 17,500 ppm on an ash basis. On the other hand, leaching was effective in recovering REEs from coarse middlings materials collected from multiple coal basins as indicated by recovery values exceeding 80%. Based on material characterization data and process evaluations conducted for several potential feed coal sources, economic recovery of the REEs will require byproduct production of both clean coal and REE concentrate using a process flowsheet that is unique for each source. INTRODUCTION Recent studies initiated by NETL showed that U.S. coals contain significant amounts of rare earth elements (REEs), suggesting that rare earth minerals (REMs) and/or REEs can be produced as byproducts [1]. According to the report, the richest source of REEs is the Central Appalachian coal. At present, there are 208 coal preparation plants located in the region (WV, KY, PA, VA, AL, TN) with a capacity of 166,495 tons/hr or more than 1 billion tons annually [2]. If only a portion of these plants are retrofitted with advanced separation processes, the U.S. coal industry can become a significant producer of RE minerals as byproducts. An inherent advantage of becoming a byproduct producer of REEs is that no mining cost needs to be part of the product cost. Other researchers have also shown that coal can be a significant source of REEs. The average sum of the rare earth plus yttrium (REY) concentration of the world coal is approximately 68.5 ppm, which is lower than the corresponding upper crustal concentration (UCC) (168.4 ppm). However, the average REY content of the mineral matter in the world (404 ppm) and U.S. coals (517 ppm) are 3 times higher than the average UCC. Some of the mineral matter in Russian and Chinese coals have REY concentrations in the range of 0.68 to 2.03% and contain a better source of higher value REYs than many primary rare earth deposits [3]."

Jan 1, 2017

By Cornelius F. Kelley

DURING the war, events moved with unprecedented rapidity. Situations, industrial, economic and financial, arose over night that stressed to the uttermost the ingenuity and ability of those who dealt with them. It was essentially a time demanding action rapid and concentrated, and not one for discussion, either academic or polemic. As a result, matters of importance were necessarily transacted without the desirable opportunity being afforded of enabling a general understanding to be gained as to the relative merit or demerit involved, and in some instances, legislation essential to enable the consummation of an important matter was passed without attracting the public attention then deeply engrossed in the larger aspects of the situation. The result was that so long as the public mind was occupied, little or no concern was given to questions that ordinarily would have invited immediate attention; and in some instances, only when as an aftermath of war a particular subject has become a matter of discussion, criticism not altogether fair is made without first obtaining accurate knowledge as to the conditions that prevailed, the purpose sought to be accomplished, or the results obtained by the action taken.

Jan 1, 1921

By S. A. Bradford

The twenty years before World War I was the Golden Age of copper smelting in British Columbia. In this short time, the smelters developed from small, primitive units to large, efficient operations. The first copper claims had been staked on Howe Sound and Knight Inlet in 1864, and there was extensive copper mining in the interior by the mid-1880s, but before 1895, all ore was shipped out of the country for smelting, converting and refining. The first interest in smelter construction was undoubtedly inspired by a Provincial bonus and Dominion land grants offered to smelter builders. The early smelters made use of small blast furnaces which were designed to smelt any kind of ore, but usually far too little ore was available. The first smelter seems to have been the McRae furnace on the Spillimacheen River (1883), followed by Vancouver (1889), Revelstoke (1891), and Golden (1891) (1). They each smelted a few tons of galena and then quickly closed down permanently for lack of ore. Only smelters that actually produced some copper matte are described in the following sections.

Jan 1, 1999

By S. L. May

Tantalum and columbium can be extracted from several of their ores or concentrates by chlorination procedures. Direct chlorination of high-grade minerals in the presence of carbon at temperatures between 500° and 800° C will extract up to 99 percent of the tantalum and columbium. Metallurgical beneficiation of low-grade source materials by carbothermic reduction produces a ferroalloy that is amenable to chlorination at a temperature of 500° C. Over 90 percent of the tantalum and columbium can be recovered.

Jan 1, 1965

By C. Hazotte, M. -O. Simonnot, V. Houzelot, B. Laubie, M. Guilpain, B. Jally

"More than 400 plants in the world are able to accumulate nickel (Ni) in their aerial parts at concentrations higher than 10 g per kg of dry biomass. Then, Ni can be recovered from the biomass of these hyperaccumulator plants. Agromining is a chain consisting in growing such plants and producing metal. It has been developed thanks to the combined know-how of agronomy and hydrometallurgy. Hydrometallurgical processes have been designed; two different pathways were developed: i) acid leaching of ashes after biomass combustion and ii) direct Ni water extraction after biomass grinding. Experiments with 2 species of Ni hyperaccumulators (A. murale from the Balkans and R. bengalensis from Malaysia) have shown that the first process is very robust and transposable. For the second one, the way Ni is stored in the plant has a strong influence on extraction. A. murale transformation was explored in more details from the lab scale to the pilot scale. Results proved that Ni is totally transferred into the aqueous phase after 2 hours at 90 °C. A life cycle assessment has clearly shown the environmental interest of this approach (especially by detoxifying agricultural soils). INTRODUCTION Agromining is an emerging phytotechnology aiming at recovering metals thanks to hyperaccumulating plants (van der Ent et al., 2018). These plants are able to accumulate very high concentrations of metal in their aerial parts. For example, for nickel, the hyperaccumulation threshold is 0.1%, i.e. 10 grams of metal per kilogram of dry biomass. There are some advantages to use this technology instead of conventional mining techniques: •,Treating unconventional metal resources: they can be (i) natural soils with low concentrations but also low fertility because of the metal presence (like serpentine soils for Ni) (Bani et al., 2015), (ii) mine tailings or (iii) industrial wastes (like surface treatment sludge) after soil construction (Rue, 2017);"

Jan 1, 2018

By Matthias Merzkirch, Volker Schulze, Kay Andre Weidenmann

"Unidirectionally reinforced light weight compounds based on light metals such as the aluminium alloy EN A W-6082 are adequate materials for the future use in transportation means like automobiles and airplanes. Due to the occurring cyclic loads knowledge about the crack growth behaviour of such composites is needed. The investigations at a load ratio of R = 0.18 show that the crack growth rate of the aluminium matrix is reduced if reinforced by spring steel wire with a reinforcing ratio of only about 1 Vol.-%. Additionally, the acoustic emission analysis allows detecting crack growth within the matrix material, crack propagation along the interface wire/matrix and crack closure which could also be determined with the help of a self designed capacitive displacement measuring gauge. The damage behaviour could be verified by metallographic and SEM investigations.IntroductionIn the field of lightweight structures for transportation means the need for light, strong and stiff materials, in particular composite materials, is increasing in order to save resources and costs. Lightweight materials such as aluminium and magnesium alloys are highly efficient candidates to be used in the composite extrusion process [1] which allows for a simple production of unidirectionally reinforced profiles with a large diversity of geometries at low costs. Figure 1 depicts the principle of the composite extrusion process; within the first part of the tool the billet material is split into several strands whereas the middle part of the tool allows the supply of the reinforcing elements. The third part of the tool rejoins the matrix material and the reinforcing elements and defines the final shape of the profile."

Jan 1, 2011

By J. B. Rubenstein

This work demonstrates the feasibility of using confocal surface profilometry to measure and characterize wear of graphite anode surfaces. This method was tested using anode samples that were electrolyzed for 24 hours in a laboratory-scale magnesium cell with a high oxide molten salt electrolyte. The oxide produced accelerated wear on anodes designed for low oxide electrolytes. Contour maps, which are effective at displaying non-uniform wear, and total graphite consumption values were generated from the collected surface coordinates. Along with both qualitative and quantitative analysis capabilities, this measurement system was shown to have a fine resolution and a low detection limit.

Jan 1, 2004

By Joseph E. Pogue

THERE are two methods employed in the development of oil pools. The older and dominant method is one in which the primary object is the protection of the underground deposit from drainage through competing wells, and considerations of efficiency of extraction and cost of production are subordinated thereto. The newer and less prevalent method is one in which maximum efficiency and minimum cost are the first objectives and developments to these ends may proceed undisturbed by the exigencies of competitive drainage. The second method has developed mainly in pools under single ownership and the term "unit operation" has come to be applied to this procedure. A single ownership, however, is not essential to the method, for unity of operation may be achieved by agreement under split ownership, or even by a concert of enlightened purpose. There are examples of unit operation where neither the ownership nor the management is a unit, but merely where unity of procedure has been attained, as is the case of the Yates pool. .Throughout this paper unit operation is used in its broad sense without implying sole ownership or single management, although unit operation is more conveniently attained where these conditions are present.

Jan 1, 1930

By Gabriel Grasselli Lorençon

Com a crescente utilização de aços inoxidáveis duplex na indústria petroquímica, química, de celulose e entre outras, motivada em grande parte pelas propriedades mecânicas e de resistência à corrosão apresentadas por estes materiais. Por se tratar de um material com altos teores de elementos de liga e ser composto por duas fases, ferrita e austenita, se faz necessário grandes cuidados na sua soldagem e um aprimoramento dos conhecimentos deste material quando submetido a este processo. Para tal, o presente trabalho denota um estudo da microestrutura de um aço inoxidável duplex após a sua soldagem pelo processo MIG pulsado, sendo aplicada uma energia durante a soldagem de 1,0kJ e adotada uma temperatura entre os passes de soldagem de 150oC. Também foram analisados os percentuais de ferrita e austenita, foi efetuada a contagem de fases do metal base e também da zona afetada pelo calor (ZAC). Foram encontrados na ZAC além da fase austenita secundária, uma fase intermetálica que possivelmente se trata de nitretos de cromo. Apesar do metal base estar com uma proporção ferrita/austenita aproximadamente igual, na ZAC houve um desbalanceamento entre as fases, onde a predominância foi de grãos de ferrita.

Aug 17, 2017

By Alessandra Vieira Guimarães

A liga de Níquel 718 é bastante requisitada para aplicações na indústria aeroespacial devido as suas excelentes propriedades. Endurecida por precipitação, a liga apresenta alta resistência mecânica sob condições extremas e ambientes severos, representando um avanço tecnológico significativo na produção de motores aeroespaciais. Os reparos realizados nos motores são feitos por diferentes processos, porém muitas vezes são realizados até que as especificações estruturais deixem de ser atendidas. Após os reparos, a liga é solubilizada em temperatura inferior a temperatura solvus da fase d, o que pode levar a precipitação crescente desta fase, podendo impactar nas propriedades da liga. O intuito do presente trabalho é avaliar o efeito de múltiplos ciclos de tratamentos térmicos de solubilização e envelhecimento na microestrutura e propriedades mecânicas da liga. Foi possível observar que os múltiplos ciclos induzem uma crescente formação de fase d, reduzindo a resistência mecânica da liga.

Oct 30, 2017

By Shenghui Guo, Jianbo Lan, Hongying Xia, Jinhui Peng, Lihua Zhang, Libo Zhang

Spent Hawaii nut shell was converted into a high-quality activated carbon via steam physical activation. Analysis of the experiment including activation temperature, activation duration, steam flow rate on the adsorption capability and yield of activated carbon were identified. Response surface methodology showed that the activation temperature was identified as 866 , an activation duration of 36 min and a steam flow rate of 2.5mL/min with the methylene blue adsorption number of 195 mg/g and yield of 77.75%. The key parameters that characterize quality of the activated carbon such as the BET surface area, total pore volume and average pore diameter were estimated to be 1125m2 /g, 0.94mL/g and 5.21 nm, respectively. Additionally, by the SEM analyses of char and activated carbon, the surface of activated carbon has large number of pores of irregular and heterogeneous morphology.

Jan 1, 2016

By Richard A. Hawkins

O the American coal man, Australian coal mining most appear to have little, if any, influence on American coal-mining practice and to bear little relation to it. Actually, the relationship has been close, for Australian operators have carefully studied American practice by reading American technical publications, by consulting American engineers, and by visits to Ameriean operations. They have leaned heavily on America for their supply of mechanization equipment and many American mining-machinery manufacturers are active in that country, supplying its needs and furnishing technical assistance. Australia's influence on American coal mining has been obscure and probably negligible. However, it seems reasonable to assume that this influence will increase. The wartime development of air transportation will inevitably bring these two countries into much more intimate contact than existed in recent years. American servicemen. many of them former miners and coal-mining technicians, have visited Australian operation, while stationed in that country, have talked with operators and men over there, and undoubt-

Jan 1, 1945

By Duclerc Fernandes Parra, Vijaya Kumar Rangari, Washington Luiz Oliani, Danilo Marin Fermino, Ademar Benevolo Lugao, Nilton Lincopan, Luiz Gustavo Hiroki Komatsu

Polyethylene is widely used for packing applications. Different grades of polyethylene, LLDPE and LDPE play a major role in the film blowing industry. The use of nanoclay in polymer matrices (non-polar) requires the use of a compatibilizer agent, ethylene graft maleic anhydride copolymer (PE-g-MA), which acts as a bridge for nanoclay-matrix-interaction. In our study, blown films of LLDPE, LDPE, and their blends were produced using a twin screw extruder. The combination of PEs as matrix, montmorillonite (MMT) and silver nanoparticles (AgNPs) intended to improve mechanical and thermal properties. Nanocomposites films with 1 wt% of montmorillonite and 0.5–1.0 wt% silver nanoparticles were prepared by blow extrusion and evaluated. Nanoclay intercalation/exfoliation degree was investigated by X-ray diffraction spectroscopy (XRD) and scanning electron microscopy (SEM). Mechanical and thermal properties were evaluated. The results showed optimum dispersion at intercalation/exfoliation levels for polyethylene nanocomposite (PENC), slight increasing in mechanical and especially improvement in thermal properties.

Mar 1, 2017

By Jian Pan, Deqing Zhu, Benjing Shi, Yuxiao Xue

COREX smelting reduction process which is freed of metallurgical coke provides a sustainable developing way for ironmaking industry. However, the shortage and high cost of pellets limit its development in China. Meanwhile, iron ore sinter has a great output in China. This work studied the reduction behaviors of sinter made from magnetite concentrates during the reducing process of COREX shaft furnace and compared the RI and RDI of sinter with BF process. The results showed that the reduction degree of sinter increased obviously during the temperature zone from 600 to 850 °C, while the reduction degradation presented rapidly aggravate in the temperature zone from 425 to 550 °C in COREX shaft furnace, and the increase of metallic iron content leads to the degradation of sinter got decreased slightly during the stage of temperature above 650 °C. Sinter got higher RI than BFprocess but also got higher RDI in low reduction temperature of 550 °C, which means sinter would have heavier disintegration in COREX shaft furnace.

Mar 1, 2017

By M. Krishna, Jayagopal Uchi1, Shanta Sastry, B. M. Satish

"A well-considered composite of ZA-27 reinforced with weight percentage 0, 2, 4, and 6% of alwninite particulate has been made by compocasting technique. The elastic properties of ZA- 27 /alwniniute particulate composite were determined by using U1M. The results showed that the modulus of elasticity and UTS of the composite gradually increases with increase in the wt.% of reinforcement. However, the overall ductility decreased monotonically with an increase in reinforcement. The results of these tests· as well as the predictions of several model~ for composite strengthening available in the literature were compared with experimental results. The data observed from Young's modulus by measurements studies were compared with theoretical results predicted by Eshelby model.IntroductionMetal matrix composites (MMCs) have received increasing attention in _the recent decades as engineering materials. The introduction of a ceramic reinforcement into a metal matrix produces a composite material resulting in an attractive combination of physical and mechanical properties that cannot be obtained with monolithic alloys. Particulate reinf9rced MMCs among the discontinuously reinforced MMCs have attracted quite a lot of attention both in the industrial sectors and the academic communities. There is an increasing need for knowledge about the processing techniques and mechanical behavior of particulate MMCs in view of their production getting enhanced and their commercial applications becoming wider [I]. Interest in particulate reinforced MMCs is mainly due to easy availability of particles and economical processing techniqu"

Jan 1, 2000

By H. Colijn

Belt conveyors have proven themselves for many years as a dependable and low cost method of handling bulk materials at high flow rates. The success of a belt conveyor system greatly depends on the initial loading of the material on the belt. If the material is loaded on the belt at the center, at approximately the same speed and with minimum impact, then most of all belt conveyor problems disappear. Proper belt loading is primarily determined by the engineering and design of the conveyor transfer point. This paper will establish and discuss some general design criteria required for proper loading and transfer of materials from one conveyor to another. Specific attention is given to loading points, chutes, skirt board length and general design of transfer structures.

Jan 1, 1971

By Yoji Imai, Akio Watanabe, Masakazu Mukaida

"To clarify the feasibility of alkoxides and acetylacetonates as precursors for laser CVD of metal oxides, vapors of tantalum or titanium alkoxides and zirconium acetylacetonate were irradiated by KrF excimer laser and deposits were characterized by XRD and XPS measurements. As for tantalum and titanium, non-stoichiometric crystalline oxides grew nearly phototropically, however, zirconium oxides deposited showed only halo-pattern by XRD measurements. Electric conductivity measurements of tantalum oxides implied the improvement of the insulating properties by the addition of activated oxygen to the ambient.IntroductionThere has been renewed increasing attention to the metallic oxide thin films because ofits promising usefulness in many applications, such as high-Tc superconductors and ferroelectric devices. A variety of thin film preparation techniques have been studied such as sputtering, chemical liquid deposition (sol-gel and metalorganic decomposition), pulsed laser deposition and chemical vapor deposition (CVD). Among them, we think CVD is the most promising method because it offers a high controllability of morphology and good step coverage at relatively high growth rate. Preparation of oxide films by CVD can be achieved using a precursor containing metallic element and oxygen containing gas such as N20 at the same time. However, metalorganic (MO) compounds which contain both metallic element and oxygen, directly bonded to metallic element, seems to be more favorable because some of MO has a good properties for CVD such as a rather high vapor pressure, stability in ambient and low toxicity."

Jan 1, 1998

By G. Ergin

The interactions taking place between Al-Mg alloys and the bed media during aluminum filtration are not yet well understood. These interactions were studied using the infiltration technique. The reaction interface was analyzed using different techniques such as SEM and TEM. Only spinel formation was observed at the interface regardless of the type of alumina and contact time. This paper discusses the results of the study.

Jan 1, 2004