Search Documents

By A. J. Lanza

IN view of the immense amount of attention that silicosis has received in this country in the past few years, it is timely to review the status of the silicosis problem at present. Who gets silicosis? The individual exposed to the inhalation of free silica dust. The effects upon the individual depend upon the amount of silica inhaled or, in other words, the severity of exposure, rather than upon any special variation or susceptibility among those exposed. A considerable amount of study has been given to determine what may be the role of predisposing causes in the development of silicosis. To mention one instance, at the Picher Clinic careful records were kept of all previous illnesses of the men examined as well as abnormalities present at the time of examination. Examinations of over 27,000 miners were made during the years the clinic was conducted under governmental auspices-a very fair sized sample. The general conclusions from all this work were that the incidence of silicosis is not appreciably influenced by racial, structural, or other inherent qualities; it is influenced by acquired defects-particularly as these affect the lungs. That is to say, the average run of human beings respond similarly to similar exposures to silica dust and those whose lungs are already impaired by tuberculosis or other pulmonary disease acquire silicosis more readily than those with healthy lungs. It may well be, and there is some clinical evidence in support, that negroes acquire silicosis more readily than do whites, but the infection factor has not been so carefully studied among negroes exposed to silica as it has among whites. We know that tubercle infection is more prevalent among negroes than among whites. There may be other factors concerned in the development of silicosis in negroes as compared to whites, but there is not available information upon which to base positive statements. INFECTION AND COMPENSATION Our first ideas about silicosis in this country were derived from early studies in the mining industry where the silica exposure was severe and

Jan 1, 1937

By Marcelo Jimenez Bustos

The Chagres Smelter was the first in Chile to follow environmental regulations to control sulfur dioxide emissions. Because of this, the operation and development plans have had to incorporate environmental planning as part of its policies for almost three decades. The present article shows the development of the environmental standards applied to its operations, investments and operational improvements carried out to meet the regulations and improve competitiveness. Results to-date and future plans are outlined, as well as their impact on operations and the environment.

Jan 1, 1993

By Gordon W. Hines

This paper, dealing with network planning in an industrial complex, discusses the type and size of project that can be handled on a manual basis. After a review of the fundamentals of network planning, and specifically of the Critical Path Method, the author analyses several different types of projects, each with its own characteristics. Some can be handled in conjunction with a computer, but others can be dealt with equally well without one. Among the projects discussed are a blast furnace reline, the installation of a billet mill flying shear, and routine maintenance-type operations.

Jan 1, 1967

By John W. Weeton, Max Quatinetz, Robert J. Schafer

Nickel powders of 1-, 0.4-, and 0.2- average particle size were combined with 0.05- p MgO powder. Oxide was added in quantities of 4, 12, and 20 vol pct. The mixtures were vacuum hot pressed and extruded at 2100°F. In spite of a general tendency to growth of oxide particles during processing, dispersions of fineness comparable to those of Sintered Aluminum Powder, SAP, were achieved. A small amount of oxide considerably improved 1800°F stress-rupture strength, but further oxide addition resulted in a decrease of strength. RECENTLY there has been much speculation concerning the requisites for strong and stable dispersion-strengthened alloys. The nature of the dispersed phase, the stability of the alloys, and variables influencing the mechanical properties of alloys have been given consideration. Such topics have been reviewed by Bunshah and Goetzel. Of the many parameters related to the mechanical properties of dispersion alloys, mean free path between dispersed particles (a measure of the fineness of the dispersion), particle size, and vol pct of the dispersed phase have been shown to be very important. Generally, strength increases with decreasing mean free path, and there is an optimum vol pct of dispersed phase. Just how fine a dispersion ought to be is somewhat open to debate, but Irmann, Lenel, Backensto, and Rose, Gregory and Grant,4 and others have shown in the original SAP-type alloys, aluminum plus aluminum oxide alloys, that better strength is generally obtained with finer dispersions and the best strengths were obtained when the mean free path was less than . Further, Cremens, and rant' showed that in nickel plus aluminum oxide alloys, stress-rupture strength at 1500°F was definitely increasing with decreasing mean free path. In their investigation, however, the finest dispersions that were produced were about 2.0 mean free path. To determine the potential of the nickel plus oxide type of product, it would be neces- sary to obtain dispersions analogous to those of SAP alloys; namely, ones where the mean free path between oxides is less than . Unfortunately, however, it is very difficult to produce extremely fine dispersions of oxides in metals other than those which naturally form refractory oxide skins. There are several approaches to this problem including such procedures as mechanical mixing, internal oxidation, reduction of mixed oxides, and metal deposition from solution. Work at the Lewis Research Center has shown that metal powders 0.1p or finer could be produced by ball milling, when selected grinding aids were utilized.' Because these unusually fine powders were available, it was an initial objective of this study to determine if by mixing of these fine Ni powders with various amounts of MgO (0.05) a fine dispersion of MgO in Ni comparable to those in Al-Al203 might be achieved. A second objective was then to attempt to relate the parameters of structure to 1800°F stress-rupture strength of the alloys. Nickel powders of 1-, 0.4-, and 0.2-p average particle size were combined with 0.05- average particle size MgO powder. This oxide was added in quantities of 4, 12, and 20 vol pct. The mixtures were hot pressed and extruded at 2100°F.

Jan 1, 1962

By J. L. Holman

In conjunction with its research program on separation, recovery, and recycling of metal, mineral, and energy-based materials in urban refuse, the U.S. Bureau of Mines is developing means to reuse and recycle plastics discarded in raw municipal waste. Experimental work on plastic waste from a community collection has produced some guidelines for systematic methods of processing, including air classification, cleaning, separation, and use or disposal. Sink-float methods are a practical means of separation into types. Methods for final disposition of the plastic waste include refabrication, thermal decomposition, and incineration.

Jan 1, 1972

By H. F. Weaver

The 19th National First-Aid and Mine Rescue Contest was held in the Civic Center, Charleston, w. Va., on October 2, 3, and 4, 1961. The meet was sponsored by the Bureau of Mines and the Joseph A. Holmes Safety Association, in cooperation with State mine inspection agencies, management and labor of the mineral extractive industries, and other groups interested in safety. The Arrangements Committee, as authorized by the General Committee, made the necessary arrangements for conducting the 1961 contest. Members of the Arrangements Committee were: George Trevorrow (chairman), Bituminous Coal Operators' Association; James B. Benson, Southern Coal Producers' Association; Charles Ferguson, United Mine Workers of America; Harry Gandy, Jr., National Coal Association; and James Westfield, Bureau of Mines.

Jan 1, 1962

By E. A. Morris

It has been shown that Alberta oil-sands fluid coke can be effectively used to reduce SO2 to elemental sulphur while simultaneously producing sulphur-impregnated activated carbon (SlAC). In the capture of mercury from industrial flue gases, SIAC has proven to be a highly effective adsorbent material. The current research aims at developing an existing SlAC technology to meet the needs of copper smelters for mitigating both mercury and SO2 emissions, while making elemental sulphur as a co-product. The challenge behind this undertaking is that these flue gases generally contain percent levels of 02 and H20 vapour (2-12%). The focus of this study is therefore on the feasibility of reducing SO2 using fluid coke under copper smelter flue gas conditions, as well as the optimisation of SIAC properties for capturing vapour phase mercury. It is hypothesised that mercury capacity is strongly affected by the 02 potential of the activation gas due to changes in surface sulphur types arising from different reduced sulphur species. To verify this, gas chromatography is used to analyse the reaction products while XPS and XANES will be used to describe the nature of sulphur on the SlAC surface. CVAFS analysis of mercury capacity will finalise the hypothesis assessment. Preliminary results indicate that 02 at 5% does not play a significant role in SSA or pore development. As expected, increased residence time contributes to SO2 reduction and elemental S yield.

Jan 1, 2007

By D. Ng

A facility to evaluate the fire endurance of mine stoppings was constructed by the Bureau of Mines in the multiple entry section of the Bruceton (PA) Experimental Mine. Stoppings up to 6 by 18 ft can be tested in a manner simulating mine conditions. The stopping is subjected to a 70-min liquid fuel tray fire with an energy output of 75,000 Btu/min. The stopping and adjacent areas are instrumented with thermocouples and heat flux gauges. Data acquisition is by an automatic data logger capable of continuously recording over 100 channels of information. Two 8-in-thick concrete block stoppings and a galvanized steel stopping were tested. A crack developed on the fire side surface of the block stoppings where the flames were most intense. However, the temperatures of the unexposed surfaces of the stoppings never exceeded 800 C and the surfaces were undamaged. The steel stopping retained its structural integrity during the test. The temperature of the unexposed steel surface reached 5000 C, but combustible materials located 1 ft from the surface did not ignite. A 3/4-in-thick coating of construction plaster was applied to the fire side of the previously tested uncoated steel stopping. The quantity of heat energy transmitted across this coated metal stopping was reduced approximately 50%. All stoppings prevented the passage of flame and smoke.

Jan 1, 1988

By Hiroyuki Matsuura

Treatment of electric arc furnace (EAF) dusts has become an important issue from the viewpoint of the environmental protection and recycling of variable resources because these dusts contain considerable amount of zinc and lead. A new recovery process of these metals has been proposed, in which the metals in the dusts react with waste polyvinyl chloride to form metal chlorides. Therefore, it is important to clarify the physicochemical properties and behaviors of zinc, lead and those chlorides and oxychlorides. In the present study, the kinetics of chlorination of ZnO, PbO and ZnFe2O4 mainly contained in the EAF dusts were investigated at 1023 K to 1273 K with Ar-O2-Cl2 gas. Based on these results, the selective chlorination and evaporation process of zinc and lead from the mixture of Fe2O3-ZnFe2O4-ZnO-PbO was examined and the high efficiency of selectivity has been demonstrated.

Jan 1, 2006

By W. R. McDonald

The Bureau of Mines, U.S. Department of the Interior, conducted small-scale field tests on acidic copper tailings as part of its effort to develop, improve, and demonstrate technology for stabilizing mining and mineral-processing wastes. Two successful demonstration revegetation plots were established on an abandoned copper-tailings pond located on public land adjacent to Holden Village, Wash. The tailings were neutralized with treatments of either dolomitic lime or limerock and fertilized with processed sewage sludge and/or commercial fertilizer. Excellent plant growths covering 70 and 24 percent of the surface were achieved on 1/8-and 1-1/2-acre test plots planted in 1973 and 1974, respectively. Regar brame, Tegmar intermediate wheatgrass, and tall wheatgrass provided the best plant growth and surface coverage. The target pH of tailings neutralization was 6.8; however, good plant growth occurred in areas where the soil pH ranged from 2.9 to 5.8.

Jan 1, 1978

By Wei Huang, Anh V. Nguyen

"Potash flotation is an industrially proven success of flotation of soluble salts, but its collector adsorption mechanism remains elusive. In this paper, specific ion effects in NaCl-KCl flotation with carboxylate collectors were investigated. Flotation recovery and contact angle were determined as a function of brine composition of NaCl and KCl. The experimental results have shown that wettability of KCl and flotation of the soluble salts with laurate collectors were dependent on brine ion composition. Specifically, adding Na+ to brines decreased hydrophobicity of KCl crystals and their flotation recovery. Both KCl and NaCl could be floated with laurate collectors. However, flotation of NaCl was greatly enhanced by adding K+ to brine whereas flotation of KCl was significantly suppressed by the presence of Na ions. The decrease in KCl recovery upon adding Na+ is attributed to the counter-ion binding in the pulp. The flotation recovery enhancement of NaCl in the presence of K+ is explained by two effects: 1) increasing K+ concentration leads to a better dispersion of collector colloids in the pulp and 2) K+ enhances the collector adsorption at NaCl crystal surfaces. The water affinity matching rule can explain the specific ion binding behaviors and supported by the SFG spectroscopic results.INTRODUCTIONPotassium is an important fertilizer. Its primary source comes from potash ores, which are a mixture of sylvite (KCl), halite (NaCl) and many other complex double salts such as carnallite (KCl·MgCl·6H2O), alkali nitrates such as KNO3 and NaNO3, and sulfates-langbeinite (2MgSO4·K2SO4) with water-insoluble minerals such as clay and carbonate minerals. Previously, these salts were recovered with a lengthy hot leaching method, with further crystallization of potassium salts from saturated saline solutions. Selective flotation has been preferred since 1940s. Various collector adsorption mechanisms have been proposed soon after the industrial introduction of potash flotation. These include the formation of the insoluble compound model (Halbich, 1933; Singewald, 1961), an ion exchange model (Fuerstenau and Fuerstenau, 1956), a heat of solution model (Rogers, 1957), the surface hydration model (Schubert, 1988), the surface charge model (Roman, 1966; Miller et al., 1992), the interfacial water structure model (Hancer and Miller, 2000) and the colloid adsorption model (Leja, 1983; Burdukova and Laskowski, 2009). Most of the early exercises attempting to propose a unified rule on collector adsorption mechanisms can be seen as heroic endeavors due to the consideration of a vast number of salts in the pulp including alkali halides, nitrates, and sulfates, even the practically insoluble heavy earth metals. Additionally, several types of surfactants with different polarization features and alkyl chain length have been employed. As for the recent models, due probably to the preferential application of long chain amines as collectors in industrial potash flotation, most researchers are only devoted to collectors with low polarization features like amines and sulfonates (Hancer and Miller, 2000; Du et al., 2014). Collector adsorption mechanisms are therefore proposed based largely on a neglect of carboxylates as collectors. However, carboxylates remain an important collector type in soluble salt flotation systems where both salt minerals can be floated using anionic collectors and cationic collectors. Fatty acid type collectors are still one of the widely used collectors for soluble salt flotation and also one of the first to be applied on an industrial scale for the separation of potash ore (Hernáinz et al., 2003; Titkov, 2004). Here we examine some recent models that are relevant to our study to reveal a long neglected specific ion binding effects in potash flotation."

Jan 1, 2016

By T. A. Rickard

The mountains of the picturesque Dauphine, in southeastern France, have long been known to collectors as the source of many minerals of rare occurrence; but. they contain also several mines, which, though less known, date from the time of the Saracens, many centuries back, to that of the graduate from the Ecole des Mines. In the department of the Isere, upon the cliffs of Villard Ey-

Jan 1, 1893

Forecasting, particularly when applied to meaningful issues, is known irreverently as 'futurology'. There is quite a range of opinion ext.ant in the world when mineral resources are looked at. The opinions range from the doomsday view that there will be acute shortages of all essential commodities, to the optimistic outlook that new 'discoveries will prevent any possibility of shortages. The environment is, as yet, only studied locally and quite parochially; surprisingly there is little integration when considering the spatial atmosphere, the seas in depth and the earth's crust.

Jan 1, 1981

By Eugenio Thiers

El presente trabajo señala la utilización de carbones andinos en la industria metalúrgica. Los países de la región andina como Perú, Bolivia y Ecuador contienen carbones coquizontes de buenas características, pero con bajo poder aglutinante. Por ello, se busca ampliar las posibilidades de su uso a través de la producción de metales. La producción se distingue en dos alternativas: primaria y secundaria. La primera incluye extracción minera, procesos de concentración mecánica, fundición y refinación, mientras que la segunda, se basa en la recuperación de materias primas a partir de la chatarra. Así también su uso principal de extiende a la siderurgia y afines.

Sep 1, 1985

By James J. Snodgrass

The Bureau of Mines has investigated vibration levels produced by blasting at four underground sites to establish how such factors as type of explosive, delay blasting, charge weight, and geology affect amplitudes of ground motion. A summary of the work is presented and the results of further analysis of the data are discussed. Square root scaling was found applicable to two of the underground sites and could be applied with minor error to all the sites. Comparison of empirical propagation equations in the different rock types indicates that although the site effect is apparent, the combined data may be used as a basis for engineering estimates of vibration amplitudes from subsurface blasting in many different rock types. Recommendations for predicting and minimizing vibration amplitudes from underground blasts are given.

Jan 1, 1974

By R. R. Falier, W. E. Rice

"PURPOSE OF REPORTThis paper presents the results of a series of tests made by the U. S. Bureau of Mines in cooperation with The Ohio State University Engineering Experiment Station as part of an investigation on the use of fuel in kilns.This report is preliminary and gives only enough of the test data to illustrate results and show the reasons for the successes and failures of the method of firing investigated; fuller details will be included in the final report.PERSONNEL FOR TESTSThe investigation is conducted under supervision of P. Nicholls, supervising fuel engineer, of the United States Bureau of Mines, and G. A. Bole, research professor, of The Ohio State University. These tests were made under direction of W. E. Rice, associate fuel engineer, assisted by R. R. Faller, assistant fuel engineer, of the United States Bureau of Mines; H. C. Harrison, senior research engineer (until October 1, 1930), C. R. Austin, senior research engineer (since October 1, 1930), and H. K. Van Sohoick, junior research engineer, of The Ohio State University. M. J. Rice, field engineer, represented the manufacturer of the stoker.PURPOSE OF INVESTIGATIONThe general aim of the investigation is to develop more economical methods of using fuel in kilns and to improve the over—all efficiency of the process of firing by methods that will produce ware of better quality. One phase of this investigation is the burning of coal on an automatic stoker to gain the advantages of control, constant rate of application of heat, and ability to burn cheaper coal than can be used in the hand—fired furnaces of kilns. It a stoker in to be used it is desirable that the coot of the installation should be low, the control of operation simple, and the distribution of heat in the kiln as good or better than with hand firing. These desiderata were sought in the stoker and furnaces that were used for the tests described herein. The tests were made to determine whether it is feasible to fire a large kiln with a single stoker, whether the use of a single furnace simplifies control, and whether the admission of all the hot gam at the center of the kiln will give symmetrical distribution of heat."

Aug 1, 1931

By Thomas Kovalchuk, Kenneth Eltschlager, William Shuss

In April of 2000, two adults and their newborn infant, were poisoned by carbon monoxide in their home and received medical treatment at a Pennsylvania hospital. Carboxyhemoglobin levels were; child - 3 1%, father - 28Oh, and mother - 17%. Initially the furnace was blamed but after further review, blasting at a nearby coal mine was determined to be the source. All other sources of carbon monoxide were ruled out. The blasting was about 400 feet from the house. The conditions that led to the migration of gas include: the blasts were highly confined, the geologic structure contained fractures that served as conduits for the carbon monoxide to reach a hand-dug well outside the house, and the well was atmospherically connected to the basement floor drains.

Jan 1, 2001

By Norihiro Murayama

Syntheses of zeolitic materials were carried out from coal fly ash by alkali hydrothermal treatment as part of the reuse and recycle technologies of coal ash, For the obtained zeolites, the cation exchange capacity and acid resistance, which are very important in the practical use of cation exchanger in aqueous solution, are investigated during this stufY, The cation exchange amounts of the NaP, CaP and K-CHA zeolites are measured for various cations such as K+, Na +, NH4+ Ca2+, Mg2+, Pb2+, Cd2+ and so on. The change in crystallization degree are researched as a function of pH. The simultaneous removal ability of NH4+ and PO43- in solution is examined for an example of the water purification with CaP zeolite. From these results, the characteristic and its mechanism of cation exchange are clarified for the various zeolitic materials obtained from coal fly ash.

Jan 1, 2003

By James R. Boyle

The Bureau of Mines initiated a program to address short-and long-term objectives of wetlands restoration as a option for reclamation of lands mined for phosphate. The short-term objectives were to identify a suitable wetland test site, initiate an extensive premining monitoring plan, develop an acceptable mining plan, and recontour and revegetate the test site. These goals were accomplished using a unique combination of expertise provided by Federal and State agencies and private industry. A 6.5-ha forested wetland with an associated streambed was offered by private industry as the test site. A premining monitoring program was established and carried out from May 1982 to October 1983. A control site was established to determine ecological changes unrelated to mining. Clearing and mining began in October 1983 and was completed in April 1984. Grading and streambed restoration was completed in February 1986. Revegetation of the site was completed in February 1987. The program to meet the long-term objective of postmining monitoring is described.

Jan 1, 1988

By V. Bari?ic

The scheduled power cuts of early 2008 were a disturbing reminder that South Africa needs to expand its power-generating capacity. Low-grade and discard coals, of which South Africa has much, are a source of energy and amenable to combustion in circulating fluidized beds (CFBs). Foster Wheeler (FW) has a long record in developing this technology in boilers. The technology is flexible in burning a variety of fuels; low-grade, high-ash coals, good quality bituminous and anthracite coals, and biomass and waste fuels have all been used. CFB boilers are efficient, reliable and can be designed to meet tight emission standards. In recent years once-through supercritical (OTSC) CFB technology has been developed. It enables the next stage in CFB development to proceed to a medium-scale (500 MWe) utility in such projects as Lagisza, which runs at a net efficiency of nearly 44%. Scaling the technology up to 800 MWe with a net efficiency of>45% is planned to be commercial during 2009. CFB technology can reduce CO2 emissions in the repowering of coal-fired and greenfield power plants. It does so through greater efficiencies and by co-combusting coal with biomass. FW has also developed CFB technology for the gasification of biomass, as, for example, in a pressurized gasifier to produce syngas, which can be used for the production of biodiesel, thereby reducing CO2 emissions from vehicles. Carbon capture and storage (CCS) can potentially cut CO2 emissions in the generation of power from fossil fuels in the short term, provided that it gains public acceptance, that the required regulatory framework is created, and that emission-trading mechanisms or other incentives provide a solid return on the major investments required. Oxyfuel combustion is an option in CCS; Foster Wheeler is adapting its CFB combustion technology for oxy-fuel combustion to meet this challenge. It is developing Flexi-burn?, which enables a plant to be operated either with or without carbon capture. This paper describes the status of CFB technology in terms of boiler efficiency and fuel flexibility. It highlights the advantages of CFB technology for oxyfuel combustion, presents a development plan for Flexi-burn?, and discusses a pressurized gasifier for biodiesel applications.

Jan 1, 2009