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

"Coal and coal byproducts produced annually contain a sufficient amount of rare earth elements (REEs) to meet current U.S. demand. The REEs exist in the form of minerals, ion-adsorbed elements associated with clays, and chemically bonded elements within the organic coal matrix or host mineral. Researchers at three universities collaborated to evaluate the effectiveness of existing physical and chemical concentration processes for the recovery of the REEs. The efforts 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. Leaching followed by solvent extraction was found to be the most effective to recover the REEs from coarse middlings materials collected from multiple coal basins, as indicated by recovery values exceeding 80 percent. 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. IntroductionRecent studies initiated by the National Energy Technology Laboratory 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 (Ekmann, 2012). 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 consisting of areas within the states of West Virginia, Kentucky, Pennsylvania, Virginia, Alabama and Tennessee, with a total capacity of 166,495 t/h, or more than 1 Gt/y (Fiscor, 2014). If only a portion of these plants are retrofitted with advanced separation processes, the U.S. coal industry would become a significant producer of REE concentrates as byproducts. An inherent advantage of becoming a byproduct producer of REEs is that no mining cost needs to be part of the production cost."

Jan 1, 2017

By Eberhard Gock

The worldwide implementation of corrosion protection of low alloyed automotive metal sheets by zinc coating has led to supply shortages of zinc free non-alloyed steel scrap in the foundry industry. In a collaboration project, partly financed by the German government, with partners from the automotive industry, zinc metallurgy, scrap trading, foundry industry, and plant construction, a new acid-based pre-dezincification process has been developed, and a pilot plant with throughput of about 100 t/d has been put into operation at the Clausthal Umwelt-Institut GmbH (CUTEC) together with the Clausthal University of Technology in Germany. During the treatment process, acid from a zinc metallurgical plant will be supplied, which can be recycled to the primary zinc extraction process after raising the zinc concentration to more than 130 g/L zinc. This way, the separation of small amounts of iron by precipitation and the electrolytic zinc winning are outsourced and, as a result, the pre-dezincification process runs waste-free. In Germany, the amount of zinc coated ?new scrap? is approx. 3 million t per year with a zinc content of approximately 60,000 t per year. The possible additional incomes for the dezincified steel scrap are in the order of ?40 to ?50 per ton of scrap, the gained zinc content during the acid dezincification defrays the costs of the process, if the throughput is more than 700 t/d. In comparison to conventional dezincification during the electro arc furnace process followed by upgrading in a rotary kiln (Waelz process), the acid dezincification process running at a maximum of 50°C will cut the energy costs by up to 74% and the CO2 emission by up to 88%. In fact, a demonstration plant is being designed right now and will be installed for processing a part of the zinc coated metal scrap from the Volkswagen AG in Wolfsburg, Germany. Keywords: steel scrap, zinc-coated steel, dezincification methods, acid

Sep 1, 2012

By Clifford S. Gibson

THE Workmen's Compensation Ace defines Silicosis as "a fibrocic condition of the lungs caused by the inhalation of silica dust sufficient co produce a lessened capacity for work". This fibrocic condition muse exhibit a specific appearance in the X-ray picture of the chest-an appearance which is not characteristic of several lung conditions which can cause lessened capacity for work and which are not due co silicosis. The layman is sufficiently familiar with this subject co know chat, as far as our knowledge goes, quartz is one of the principal objectionable factors in the production of this condition. He should also know that silicosis respects neither geographical nor industrial boundaries. It is as much a factor in some industrial processes (e.g. foundry work, sandblasting) as it is in mines handling ores containing quartz. Its development co a recognizable stage is usually a matter of many years. As yet, its cure is unknown. Its prevention is possible in varying degrees. The layman should also know that the development of fibrosis may be accelerated by breathing in, or living in, any atmosphere containing dust. Few normal adults, particularly those above a certain age, have clear lungs, and fibrosis in varying degrees is noted in the farmer, the steel worker, the clerk, and many others in varied occupations. It is not restricted to miners. Medical and industrial journals, and at times the press, are crammed with data pertaining to this subject, much of which is misinformation. This is particularly true of certain !laces where the preventive and compensation measures for the good o those earning their livelihood in an industry in which silicosis may be contracted are not so far advanced as in our own Province. A great many of these publishings are alarming to the layman. They leave him with the impression that he is taking his life in his hands if he elects to work underground, particularly in a gold mine-that he has at once sold his heritage of health and chat sooner or later he will succumb to the ravages of this ailment. Nothing could be farther from the truth. Actually, under present conditions in Ontario mines, a very small percentage of the men employed ever become impaired by silicosis to the extent chat they must withdraw from the industry. I propose to tell you briefly something of this subject as it affects our mines.

Jan 1, 1937

By W. M. Husslage

The permeability in the blast furnace shaft is adversely affected by low temperature reduction degradation of sinters. The fundamental cause is an expansion of the iron oxide phase resulting from reduction of hematite to magnetite. The present study showed that expansion behavior during the hematite / magnetite reduction step and the resulting microstructure are strongly influenced by the reduction temperature (viz. partial oxygen pressure), the reducing agent and the nature of the hematite. The reduction rate is of minor importance. A reduction mechanism is proposed, explaining the dilation behavior and the magnetite microstructure. The results can provide better insight into reduction degradation behavior.

Jan 1, 1998

By E. A. Sobering

Hydraulic filling or sand filling is a system used to fill underground excavations with a dense pulp. Milltailings are commonly used. The resultant fill, after being placed and de-watered, is known as hydraulic fill. These fills have been effectively used to (a) provide immediate support of the workings place during stoping; (b) .facilitate the recovery of pillars; (c) limit surface damage by subsidence; (d) permit the mining of parallel hanging-wall orebodies; (e) stabilize the ground in mines, thereby reducing the rock burst hazard; (f) control and prevent mine fires; and (g) solve tailings disposal .problems. The various uses of hydraulic filling have been developed during the last ninety years. In 1864 it was employed only to control surface subsidence. Since then, this system has been successfully applied to meet specific ground support problems. Methods of handling mine-fill derived from a source outside the stope include transportation ?Of the material by hand, mechanical, pneumatic, and hydraulic means, or a combination of these methods. The hydraulic method has many advantages not found in the others; a significant advantage is the low compressibility of the material when compared to other mine-fill material. The hydraulic filling operation includes the .preparation and transportation of the pulp. The underground practices in .placing the fill vary from mine to mine. The chief reason, formerly, for using hydraulic fill was the exceptional support it provided, but recently it has proven an important means of reducing mining costs. This is especially true where labour is a large part of an alternative method, or where timber consumption is greatly reduced. The indirect benefits of hydraulic filling are probably as important as the direct benefits, and few important disadvantages exist.

Jan 1, 1956

By M. Moinpour, E. Liao, C. Y. Aw, D. J. Brown, P. W. Cheung

"Currently, silicon-based insulated-gate field-effect devices are being widely developed as the basic structural elements in a new generation of chemical microsensors. In this paper, we discuss some of the process considerations related to the fabrication of the Chemically Sensitive Field-Effect Transistor (CHEMFET). This ion-sensitive CHEMFET (or ISFET as it is often called) can be used for pH measurements (i.e., as a pH sensor) when the gate insulator of the electrolyte/insulator interface is made of Si3N4 obtained by the LPCVD method. Effects of processing parameters such as the Si3N4 deposition rate, gas composition, total flow rate, annealing treatment, etc. on Si/Si02, Si/Si3N4 and Si/Si02/Si3N4 structures are discussed in relation to the CHEMFET fabrication. Their effects on the electrical characteristics and chemical response of the sensor are also examined. Capacitance-Voltage (C-V) measurements and ESCA analysis have been used to interpret the results. The Si3N4/Si02 double dialectric layer provides improved ion blocking for the gate insulator in electrolyte solutions with enhanced pH sensitivity over time. The stability and performance of the fabricated CHEMFET sensors were tested by measuring the pH sensitivity in various storage conditions. The SEM analysis was used to evaluate the hydration effect at the ISFET's gate insulator with respect to different storage conditions.IntroductionThere has been a continuous interest in the development and fabrication of various chemical microsensors for chemical and biomedical applications over the last fifteen years. The application of semiconductor (particularly silicon) technology to the area of sensor fabrication has led to an emergence of a new generation of miniaturized, microelectronic, solid-state chemical sensors. There are numerous clinical situations where continuous monitoring of body electrolytes concentrations such as Na+, K+, Ca+2 , etc. and blood gases (pH, Po2 , and PC02) would be essential for the effective diagnosis and management of patients under critical conditions. Solid- state microsensors can be used for direct and continuous in vivo measurement of the above parameters in most instances."

Jan 1, 1988

By Walter R. Storms

This paper, which describes the mining methods of the Potash Co. of America in Eddy County, N. Mex., is one of a series being prepared by the Mining Branch, of the Bureau of Mines on mining practices and methods in various mining districts of the United States. 4, T. The mine and plant of Potash Co. of America are situated in sec. 20 S., R.. 30, E.,. N. M. P. M., about 22 miles by paved road northeast of Carlsbad (fig. 1). A spur line of the Atchison, Topeka & Santa Fe Railroad also connects the mine with Carlsbad.

Apr 1, 1948

By H. Herbert Hughes

Iceland spar is a variety of calcite ( calcium carbonate ) characterized by its purity , transparency , and perfection of crystalline structure . It takes its name from the country in which it was discovered . The actual demand for it is small , but the supplies of high - grade optical spar are so meager that the search for it has become international in its scope . Iceland spar is a scientific necessity , for without it research precision and technology would be hampered considerably . The earliest students of mineralogy were familiar with calcite , but the transparent variety was not discovered until early in the seventeenth century , when crystals of it were found in the bed of a stream in Iceland . It received little attention until 1669 , when Erasmus Bartholinus first recognized its powers of double refraction . The results of his investigation were published in a book , " Experimenta Crystalli Islandici , " which appeared in 1670. The law governing the action of the rerracted rays was discovered by Christian Huygens eight years later . The polarization of light rays in passing through Iceland spar was discovered in 1809 by Etienne Louis Malus , a French physicist , who published a paper describing the phenomenon . His work was closely followed by that of William Nicol , who in 1828 designed the Nicol prism which is still used as the source of polarized light in most optical instruments .

Jul 1, 1931

By Walter E. Lewis

This circular presents the method of making tests and apparent results of comparing performance of tungsten carbide insert bits and steel detachable bits by the Cleveland-Cliffs Iron Co. at the company's mines on the Marquette iron range of Michigan. The mines are at Ishpeming and Negaunee, Mich., and include the Cliffs Chaft, Mather "A", Cambria-Jackson, and Mather "B". There are four general characteristic types of high-grade iron ore on the Marquette range. B. H. Boyum2/ classifies the Cliffs Shaft as "hard-ore" and the Cambria-Jackson and Mather "A" as "soft-ore" types of deposit. Shaft sinking through Jasper, slate, and graywacke was in progress at this writing at the Mather "B", with completion at 3,100-foot depth in August 1949. The many different kinds of rock and ore at the mines of the Cleveland- Cliffs Iron Co. and the experimental work being carried on with carbide in- sert bits make it possible to compare, generally, the carbide insert and steel detachable bit. The type of "hard ore" at the Cliffs Shaft mine re- quired close study of the possible use of the insert tit, and their records are more complete than those of the "soft-ore" mines. History and development of tungsten carbide tips inserted in rock drill bits have been covered by R. W. Adamson, C. H. Vivian, R. C. Sullivan,5/ and others. Tungsten carbide insert rock bits have only recently been introduced to the domestic mining industry. Although unusual performance records are being reported at operations employing the insert bits, the general adaptability of the tool to all rock types and the advantages to be gained by using carbide insert tits remains to be demonstrated. Insert-bit performance is being observed at numerous mines and quarries throughout the United States The several mining operations at the Cleveland-Cliffs Iron Co. at Ishpeming, Mich., is one site where exhaustive comparative tests of insert and conventional steel detachable bits are currently in progress. Results to date are sufficiently impressive to be of general interest to the mining

Mar 1, 1950

By Thomas J. Peters

The Danskin/South Fork Boise River study area is 40 air km southeast of Boise, Idaho. The 16,000-hectare, two-segment area is mainly underlain by Cretaceous-age granodiorite and an aplitic and pegmatitic complex of the Idaho batholith, Miocene-age rhyolitic tuffs and lavas, and late Tertiary-age basalt flows. No mineral resources were identified in the study area. One mine, The Flat Creek mine, which produced several ounces of gold and silver, was found in the study area. It is geologically similar to deposits in the Neal mining district, adjacent to the northwest corner of the area; gold mineralization occurs along east-northeast-trending faults and associated quartz veins, which dip moderately to steeply southeast, and within adjacent Cretaceous granitic rock. Samples indicate the Flat Creek deposit is not rich enough to mine underground, and near surface, open-pit-mineable deposit areas could not be identified. However, exploration is warranted there and also in the 7-km interval to mines in the Neal district, and for extensions of those mines. No evidence of geothermal activity was observed, although there are hot springs in the vicinity. Some alluvial (placer) samples from the interior of the study area contained free gold, but no substantial gravel deposits were seen.

Jan 1, 1993

By Curt D. Edgerton

This study was made to determine trends in fresh water usage by California petroleum refineries, to forecast fresh water requirements to 1975, and to evaluate water conservation practices. Statistical data used in the study were obtained largely from published sources and from records of selected companies. An adequate sampling of the State's refining capacity was obtained, and the data were extrapolated to the total California refining capacity. A breakdown of the data was then made on the basis of the following refining regions: (1) the Los Angeles Basin and Southern Coastal region, (2) the Southern San Joaquin Valley, and (3) the San Francisco Bay area. An unpublished forecast of crude oil input to refineries by a major oil company operating on the West Coast was used as a basis for predicting fresh-water usage. The 1963 fresh water intake by California petroleum refineries was 84 million gallons per day. This is expected to increase to 128 million gallons per day by 1975. The fresh-water to crude-oil ratio is increasing in all regions except the Southern San Joaquin Valley. At present, the supply of fresh water available to almost all of the State's petroleum refineries, mostly from surface sources and company-owned wells, is adequate, although shortages may develop within the foreseeable future. Present conservation methods are centered around the following four objectives: (1) minimum intake of fresh water of the lowest possible quality commensurate with sound technologic practice; (2) optimum recirculation; (3) proper treatment before discharge; and (4) substitution of air cooling for water cooling.

Jan 1, 1965

By Walter Estrada, Fernando Valencia, Jaime Luyo

La gasificación por plasma es un proceso térmico a alta temperatura en el que los desechos se descomponen en elementos fundamentales y compuestos simples en un entorno anaeróbico. El sistema presentado en este artículo actúa como un digestor al transformar las moléculas de carbono y otras sustancias en compuestos menos contaminantes. Se utilizó una mezcla de cianuro disuelto en agua como muestra de ensayo —procedente de aguas de una mina—, que se sometió al componente radiante de plasma, y se estudió la energía generada actuando sobre la purificación y transformación de las muestras.

Sep 30, 2019

By G. L. Oldright, Virgil Miller

"This paper is the eighth; of a series on smelting in the lead blast furnace, and the third' of a group on the modifications brought about by the introduction of rich charges.ACKN0WLEDGMENTSThe data that appear in these articles were obtained through the courtesy of the operators of the Bunker Hill smelter at Kellogg, Idaho. The authors take this opportunity to express their appreciation to Stanley A. Easton, the vice-president and general manager, Frank M. Smith, smelter director, and to A. F. Beasley, the smelter superintendent, and his staff.INTR0DUCTI0NIt has been noted that the gases issuing from the top6 of the charges in the International Smelting Co.'s furnaces at Tooele, Utah, were very similar in composition to the gases from the top of the iron blast furnace, as they contained about 26 per cent of CO and 12 per cent of C02, the rest of the constituents being mainly nitrogen with a very little hydrogen and oxygen. It has been seen that where the column of coke was sufficiently high, the production of C0 gas to carry out the reduction of lead ores was accomplished in about the same manner as in a gas producer. In some cases, there was a little oxygen in the ""top gas"" -- usually not over a few tenths of a per cent, but at times amounting to several per cent. The presence of this gas was attributed to irregularities in operation that permitted air to come up through the tuybres to the surface without meeting any coke that was incandescent. Only a hundredth of a per cent or so of sulphurous oxides was present in the gases issuing from the top of the furnace."

Apr 1, 1931

By Curt D. Jr. Edgerton

This study was made to determine trends in fresh water usage by California petroleum refineries, to Forecast fresh water requirements to 1975, and to evaluate water conservation practices. Statistical data used in the study were obtained largely from published sources and from records of selected companies. An adequate sampling of the State's refining capacity was obtained, and the data were extrapolated to the total California refining capacity. A breakdown of the data was then made on the basis of the following refining regions: (1) the Los Angeles Basin and Southern Coastal region, (2) the Southern San Joaquin Valley, and (3) the San Francisco Bay area. An unpublished forecast of crude oil input to refineries by a major oil company operating on the West Coast was used as a basis for predicting fresh-water usage. The 1963 fresh water intake by California petroleum refineries was 84 million gallons per day. This is expected to increase to 128 million gallons per day by 1975. The fresh-water to crude-oil ratio is increasing in all regions except the Southern San Joaquin Valley. At present, the supply of fresh water available to almost all of the State's petroleum refineries, mostly from surface sources and company-owned wells, is adequate, although shortages may develop within the foreseeable future. Present conservation methods are centered around the following four objectives: (1) minimum intake of fresh water of the lowest possible quality commensurate with sound technologic practice; (2) optimum recirculation (3) proper treatment before discharge; and (4) substitution of air cooling for water cooling.

Jan 1, 1965

By AIME AIME

CERTAINLY in point of attendance, and doubtless in several other ways as well, the 147th meeting of the A.I.M.E. was the best ever held. In times of depression, mining engineers and metallurgists have plenty of time to come to the Annual Meeting but money is scarce; at the height of industrial activity they have plenty of money but no time. "The current period of transition seemed to provide ideal conditions for' both the preparation of papers and attendance at their presentation. The weather made even the Californians present envious though the weather man gets no credit, for rain and snow was what he willed. Among the elevator men, the miners have the reputation of being the toughest crowd to handle, though the best natured, withal, of all the engineering groups that meet in the Engineering Societies Building. This year Your inquiring reporter was told, "it was the damnedest meeting I ever saw; they

Jan 1, 1937

By Irving Hartmann

At the 9th International Conference of Directors of Safety in Mines Research a paper6/ was presented describing the initial phases of research by the Safety in Mines Research Establishment at Buxton, England, on the remote control of timber fires with high-expansion foam plugs in a rock tunnel. The work received extensive publicity, and great interest was aroused by the implied possibility that the method might be used successfully to control coal-mine fires, which for various reasons cannot be approached and attacked by standard fire fighting measures and frequently require sealing extensive, valuable coal properties and lead to loss of production and coal reserves and occasionally loss of lives. To investigate the practicability of the foam-plug technique under American min¬ing conditions, with room-and-pillar-type extraction and multiple entries, the Bureau of Mines in 1957 began an investigation at its Experimental Coal Mine, Bruceton, Pa, In preparation for this work it was necessary to rehabilitate and reinforce an elliptical tunnel in the mine where studies had been made, many years ago, leading to development of a ventilation system used in the Holland Tunnels between New York and New Jersey, and in many other vehicular tunnels.

Jan 1, 1958

By T. Shariff

Titanium alloys have found increasingly wide range of applications in aerospace, chemical, medical, sporting, power generation, oil and gas extraction industries mainly due to the low density, high mechanical property characteristics, biocompatibility, and excellent corrosion resistance. In the manufacturing routes of their finished products, welding has been a key technique used and always been a main concern requiring the stringent compliance to the well defined process. Conventionally, gas tungstenarc (TIG), gas metal-arc (MG), plasma arc, and electron beam welding processes have been used to weld titanium alloys. Nowadays, laser beam welding has provided great challenging applications for titanium alloys due to the low and precise heat input, deep and narrow fusion zone, small heataffected zone, low thermal distortion and high productivity. At the NRC Institute for Aerospace Research, some R&D work has been undertaken for titanium alloys using laser beam welding process. These investigations have mainly concentrated on optimizing the welding process as well as understanding the fundamental process-structure-property relationships. In this invited keynote presentation, the research progresses obtained and the main issues encountered in laser welding of titanium alloys will be briefly summarized.

Jan 1, 2011

By Túlio Magno Fuzessy de Melo, Luciano Santos Marques, Vicente Tadeu Lopes Buono

The influence of the coiling temperature after hot strip rolling on the microstructure and on the tensile and hole expansion properties of a 800 MPa multiphase steel was investigated. For the temperatures between 150°C and 600°C the microstructure consisted of a ferritic matrix with a dispersion of fine martensite-austenite (MA) and regions of degenerated upper bainite. In all cases the ferrite presented a heterogeneous mixture of polygonal, quasi-polygonal and acicular grains. The yield and tensile strengths showed a tendency of decreasing with the increasing coiling temperature, probably because of the larger fraction of MA particles at lower temperatures and higher fraction of quasi-polygonal ferrite at higher temperatures. The elongation was not significantly affected by the variation of coiling temperature. The average hole expansion ratio showed a maximum of 80% for the material coiled at 400°C and fell below 50% only for the coiling temperature of 150°C, probably due to the larger hardness difference between the ferrite matrix and the MA particles.

Oct 1, 2019

By Suzana Souza da Silva Scardua

O desenvolvimento dos aços microligados representa um grande avanço tecnológico e oferece grandes vantagens econômicas para diversas áreas da engenharia. Nas últimas décadas houve um aumento expressivo na demanda mundial por tubos utilizados na construção de dutos para transporte de petróleo e gás. Neste caso são utilizados os aços ARBL (Alta Resistência e Baixa Liga) que combinam alta resistência e tenacidade necessárias para operar em altas pressões. Os tubos são produzidos a partir de placas laminadas e posteriormente soldadas atendendo a norma API 5L. Em componentes de geometria complexa, tais como juntas, acoplamentos e conexões, a laminação não é a técnica mais adequada. Para este fim, o processo de forjamento é uma alternativa, pois permite uma ampla faixa de dimensões e formas complexas com controle da microestrutura e propriedades mecânicas após tratamentos térmicos adequados. Para avaliar novas técnicas de processamento, foram fabricadas barras forjadas de um aço microligado com composição química similar à de um API 5L X70 comercial. O aço foi lingotado e forjado em barras quadradas de 35 mm de aresta. Em seguida foram retiradas amostras para tratamentos térmicos de têmpera a 920°C e 1.050°C e revenimento de 150°C a 650°C. Após analisar as microestruturas foi escolhida a similar à de um tubo comercial API 5L X70 para preparação de corpos de prova para ensaios de tração. Resultados preliminares mostram a possibilidade de obter aços com qualidade API através do forjamento.

Aug 7, 2018

By A. R. Chambers

At the 1924 Annual Meeting of the Institute, held in Toronto, the writer presented some notes on the occurrence of salt at Malagash, Nova Scotia, together with a few remarks on the uses of salt. The development of these salt mines has attracted considerable attention to the district, and it may be of interest at this time to call attention to some of the newer uses of salt, and to give a brief account of the genesis of the Maritime salines, As it is not proposed to treat the subject in technical detail, and the paper is written in a lighter vein than is usual in contributions to your Transactions, you will please overlook any variations from a strictly technical method of presentation. The world's supply of salt is obtained in three principal ways: (1) By flooding shallow areas, or pans, with sea water, allowing the water to evaporate naturally by the heat of the sun's rays, and collecting the residue of solid salt. This method is employed, for example, at Turks Island, B.W.I. (2) By mining the rock salt in its natural state, and preparing it for market by a grinding process. This is the method adopted at Malagash, which is the only place in Canada where salt is actually mined. (3) By drilling a hole into an underground salt deposit, forcing fresh water clown the hole, and, after it has become saturated with salt, pumping the brine to the surface and recovering the salt by evaporation. This is the method pursued by the Canadian Salt Company, the Dominion Salt Company, and other producers in Ontario.

Jan 1, 1929