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By John M. Gomes

A two-phase molten halide-silicate technique for extracting tungstic oxide (WO3) from scheelite (CaW04) and wolframite [(Fe, Mn)W04] was investigated. The halide phase extracted over 99 percent of the was, whereas the lower silicate phase retained about 90 percent of the calcium, iron, or manganese oxides. The most efficient extraction and separation of tungsten from scheelite was accomplished at 1,080° C in a molten system containing, in mole-percent, 9 calcium tungstate (CaW04), 42 sodium chloride (NaCl), 28 sodium fluoride (NaF), 17 sodium metasilicate (Na2SiO3), and 4 alumina (Al2O3). Wolframite was also treated at 1,0800°C; the molten system contained, in mole-percent, 11 (Fe, Mn)W04, 74 NaCl, and 15 Na2 SiO3.

Jan 1, 1968

By Scott W. Hazen

COMPREHENSIVE summary is presented of results of several years of research at the Bureau of Mines Mining Research Center at Denver on adapting and applying techniques of statistical analysis in mine and mineral-deposit sampling and in computing grade and tonnage of ore for a mineral deposit. In addition to elementary statistical theory the material presented in the bulletin includes: (1) Certain special statistical techniques that have been found useful in mining applications; (2) problems, implications, and limitations that may be encountered in applying these techniques in mine sampling and evaluation; and (3) numerous examples to demonstrate application of the theory and techniques.

Jan 1, 1967

By R. L. Beatty

IN INDUSTRIAL and domestic daily life carbon monoxide is the most frequently encountered toxic gas. hazardous concentrations of carbon monoxide may be present in the vicinity of many industrial operations, such as metallurgical processes, coke ovens, and fuel- and synthesis-gas producers, and may be encountered in confined spaces, such as dwellings, garages, workshops, vehicular tunnels, and mining operations, in connection with the use of heaters, boilers, internal-combustion engines, after blasting operations, and after fires and explosions. Evaluation and control of the health and safety hazard caused by carbon monoxide depend primarily on the analytical detection of the presence of carbon monoxide and determination of its concentration in air and in various gaseous mixtures. The choice of method of analysis in any particular situation depends on such factors as required accuracy, range of concentration involved, convenience, speed of analysis required, quantity of sample available, qualitative composition of sample or atmosphere to be analyzed, and possible effects of interfering gases. Some of the methods described require only adequate understanding of operational techniques, whereas others require thorough appreciation and skill in applying the principles involved. The instruments and analytical procedures commonly used for detecting and determining carbon monoxide are described in detail, and reference is made to more specialized methods:

Jan 1, 1955

By John F. Papp

The objective of this U.S. Bureau of Mines study is to calculate an accurate, reliable estimate of chromium and nickel content of stainless and heat-resisting steel produced in the United States. The columbium, manganese, molybdenum, titanium, tungsten, and vanadium contents of this steel are also calculated. Such contents are required for estimating the quantity of alloying element recovered from recycled stainless steel and consumed by market sectors. In this investigation, the elemental fraction of stainless and heat-resisting steel was calculated as the ratio of the weight of element contained in stainless steel to the weight of stainless steel produced. The elemental fraction has been calculated as a time-averaged, grade-averaged value. The elemental fraction was averaged from 1962 through 1983, and averaged over the grades for which production was reported by the American Iron and Steel Institute during that time period. The 1962-83 average elemental fraction of U.S.-produced stainless and heat-resisting steel was calculated for chromium to be about 0.17 ± 0.01; columbium, 0.00014 ± 0.00003; manganese, 0.015 ± 0.005; molybdenum, 0.004 ± 0.001; nickel, 0.07 ± 0.01; silicon, 0.009 ± 0.001; titanium, 0.0004 ± 0.0001; tungsten, 0.0001±0.00003; and vanadium, 0.00003±0.0000l.

Jan 1, 1991

By Kenneth R. Maser

This report describes a research and development program sponsored by the United State s Bureau of Mines. The purpose of the program was to develop reusable explosion-proof bulkheads for a cross-cut emergency shelter, and to study the implementation of such bulk-heads, and the resulting shelters, as part of an emergency escape plan in a normal coal mining environment. The first part of this report reveals a number of significant conclusions regarding the application of emergency shelters. A study of the cause s of, and the conditions prevailing during a mine emergency indicate s that ideal placement of the shelter s would be midway along developing entries, and at the inter section of butt and main entries. The proper spacing of shelters is based on the travel capability of trapped miners, which is in turn dependent on the height of coal. The life of a given emergency shelter, based on an analysis of the above information, will be anywhere from 6 months to 10 years. Consequently, some shelters are regarded as "temporary?, while others "permanent?.

Jan 1, 1975

By J. D. Davis

The Bureau of Mines Coal Carbonization Laboratory has been interested for the past 20 years in the quality of coke in connection with the selection of coals for the manufacture of coke. The principal experimental. method of carbonization, whereby 100- to 200-pound charges are carbonized in sheet-steel cylindrical retorts with recovery and determination of the properties of coke, gas, and products, was developed in cooperation with the American Gas Association,4 5 and it is known as the BM-AGA method. Results of the investigations of 90 coals included in the BM-AGA Survey of the Carbonizing Prop¬erties of American Coals have been published; 6 and, in addition to these, about 200 coals have been carbonized over limited temperature ranges. Because coke from cylindrical retorts differs in shape from that made in rectangular ovens, the BM-AGA method has been criticized, although those who developed it have always believed that it served well as a means of measuring the relative strengths of cokes from different coals. It is recognized that no laboratory-method carbonization, even on a large twit, can yield results that exactly duplicate those obtained in commercial ovens and retorts. However, with the completion and satisfactory performance of an experimental vertical slot oven of 500-pound capacity at the University of Illinois Geological Survey Laboratory,' the opportunity to directly compare BM-AGA coke with coke made by two-sided heating became available and the necessary test apparatus was installed. The Bureau of Mines slot oven, which is similar to that designed by the University of Illinois Geological Survey, has been used to carbonize 11 coals (or blends) tested by the BM-AGA method. This report compares the results obtained by the two methods.

Jan 1, 1950

By Thomas P. Mucho

Cable bolts are emerging as the newest ?twist? for roof support in U.S. underground coal mines. For decades cable bolts installed in underground metal mines in the United States and Canada used cement-based grouts for anchoring. The cement anchoring process, because of the time and expense for installation, made cable bolts impractical for use in coal mines. Today, the introduction of resin-anchored cable bolts provides a system more consistent with tradi­tional U.S. coal mine roof bolting practices and requirements. Expecta­tions are that the utilization of cable bolts for a number of U.S. mining applications will expand, particularly in coal mining.

Jan 1, 1998

By Robert E. Barieau

In the design of plants to separate helium from natural gas, it is necessary to estimate the enthalpies of the various streams at various positions in the process. This Bureau of Mines report surveys the various methods that have been used to determine enthalpies and gives information on the organizations with such capabilities. The minimum information required for developing an enthalpy diagram is presented, and the relative merits of the various methods are discussed. It is concluded that methods that require no mass flow rate or energy measurements are to be preferred.

Jan 1, 1965

By R. R. Wells

An important activity of the Bureau of Mines is the continual search for new sources of minerals. As a part of the investigation of strategic mineral deposits in the United States, samples of mercury ores were submitted to the Ore Dressing sections of the Salt Lake City and Albany stations for metallurgical testing. This paper gives data summarizing the results obtained from laboratory beneficiation studies of mercury ore samples submitted during the period 1941 to 1947. Ores tested included three from Jackson County, Oreg., one from Valley County, Idaho, one from Storey County, Nev., and one from Sonoma County, Calif. In general, the ores from Oregon were not amenable to concentration by flotation because of intimate association of cinnabar with other minerals or because of extremely low grade. One Oregon ore was amenable to direct distillation provided lime was added to reduce corrosion of the retort.

Jan 1, 1950

By Barry Beith

This report details a study which was designed to assess the effect of retroreflective material on detection and form recognition of workers in the mining environment. Further, the study attempted to determine an optimal configuration of retroreflective material with respect to amount and placement on the body to facilitate detection and form recognition. The study involved a one-fifth scale simulation of the perceptual task found in the underground low seam coal mine. Four different configurations of reflective material were presented in various body positions, common to low coal miners, at three different locations in the visual field, i.e., 10, 25, and 45 degrees from focal line-of-sight. All reflective configurations significantly improve detection and form recognition over configuration (cap only) worn by miners. As the amount of reflective material increased, accuracy also tended to increase. Based on the configurations investigated by this study, the Armband configuration (i.e., refectorized armbands, belt, self-rescuer and battery pack) was determined to be optimum. It is recommended that an actual field evaluation be made using the Armband configuration to establish if simulator results are generalizable to the underground mining environment.

Jan 1, 1980

Numerical models play a significant role in the design of safe underground mining excavations and support systems. Advances in the capabilities of numerical modeling software, together with ever increasing computational speeds, have made it possible to investigate the very nature of the large-scale rock mass and its response to mining excavations. The improved understanding of the rock response obtained from modeling enhances our designs, resulting in greater stability and safety of the mining excavations. To help advance the state of the art in this field, the National Institute for Occupational Safety and Health organized the International Workshop on Numerical Modeling for Underground Mine Excavation Design. The workshop was held in Asheville, NC, on June 28, 2009, in association with the 43rd U.S. Rock Mechanics Symposium. The proceedings include 10 papers from leading rock mechanics and numerical modeling experts in the United States, Canada, Australia, and Germany. The papers address a wide range of issues, including various numerical modeling approaches, rock mass modeling, and applications in coal and metal mines.

Jun 1, 2009

By Larry A. Haas

The U.S. Bureau of Mines, in cooperation with Cleveland-Cliffs, Inc. (Hibbing, MN), investigated ways of enhancing the quality (compressive strength, after-tumble and reducibility) of domestic acid and fluxed magnetite pellets by modifying the oxygen content during the preheat and induration periods of the firing operation . Oxidation of magnetite was best accomplished when sufficient oxygen and time were available before the peak induration temperature was reached. The rate of magnetite oxidation increased directly with the gas oxygen content during the preheat period at 7000 C and above. With 30 pct ( or more) O2 and a preheat rate of 2000 C/min, most of the magnetite was oxidized during the preheat period. With laboratory tube and mini-pot furnace tests, oxygen enrichment during the preheat period improved the pellet properties more in the simulated grate-kiln tests than in the simulated straight-grate tests. The longer induration period with the grate-kiln test resulted in more sintering of the residual magnetite and its reaction with the silicon compounds. When flux was present in the pellets, calcium silicates and calcium and magnesium ferrites were formed. More calcium ferrite was formed when the magnetite was oxidized early and less iron was present in the fayalitic calcium silicate slag.

Jan 1, 1993

By Clyde L. Brown

Recent developments in portable communication equipment for use in emergency recovery work following mine fires and explosions have wade possible a convenient and dependable means of directing rescue teams working under hazardous conditions. INTRODUCTION Mine rescue and recovery operations following; fires and explosions are frequently conducted under adverse conditions that require the use of oxygen breathing apparatus by members of a 5- or 6-man team. Conventional apparatus used for this purpose for many years was equipped with an oxygen supply adequate for at least 2 hours. The design of the apparatus is such that the nose passages are closed with a clamp, and breathing is accomplished through a mouthpiece connected to the apparatus by tubes and arranged to prevent inhaling air or gases from outside sources. The use of the mouthpiece has presented difficulties in the development of telephone communication because of the wearer's inability to speak while wearing the mouthpiece. The method of conducting operations of rescue teams requires a person to direct operations at a fresh-air base as close to the rescue team as possible. At least one standby rescue team and 2 or 3 other persons assigned to various tasks are stationed at the fresh-air base. An efficient and reliable means of communication between the director of operations and the rescue team is necessary for reasonably safe and efficient work in hazardous areas.

Jan 1, 1957

By H. W. Wainwright

One phase of the research and development work on synthetic liquid fuels conducted by the Bureau of Mines at Morgantown, W. Va. in cooperation with West Virginia University deals with the purification of synthesis gas.2/ Most of the experimental studies on gas purification have been directed toward the removal of organic sulfur from gas, either catalytically or by adsorption with activated carbon. An important part of the purification program has been the development of suitable analytical methods for determining organic sulfur compounds. As the total sulfur content, organic and inorganic, of purified synthesis gas should not exceed 0.1 grain per 100 cubic feet, the need for accurate analytical methods is apparent. It is also apparent that such methods must be rapid if one wishes to evaluate various processes for removing sulfur from gas. The organic sulfur found in most gas produced from coal is usually present as carbon disulfide, carbon oxysulfide, methyl and ethyl mercaptans, and thiophene, with the exception of thiophene, the remaining organic sulfur compounds respond similarly to catalytic treatment and can be removed effectively. Not only does thiophene resist most catalytic treatment, but it poisons some catalysts, rendering them ineffective in removing the other forms of organic sulfur.

Jan 1, 1950

By Arthur L. Murray

"Oil-shale camps are peculiarly favored, in that before they are establishes it can be ascertained with a degree of certainty, that the life of the project is not limited. Unlike camps at metal mines, where the metal content of a given area is frequently an unknown quantity until after years of development, oil-shale camps should, from the outset, be planned and. built as permanent types of camps. Where this procedure is followed camps will be established which better serve the needs of the industry and the cost of their general care and upkeep will be less.Selection of camp or townsite.The site of the camp or town' whether on company property or not, should be selected with care. It should be separate if possible from the location of the plants of the company so as to be free from noise and fumes and so as to provide a change of environment for employees in going from their work to their homes.The principal features governing the site to be selected are as follows:Drainage. The general contour of the surrounding country should be such that drainage is away from the site. The camp or town should, if practical, be situated on higher ground than that in its immediate vicinity.Soil. The nature of the soil on which the camp or town is located may bear a decided relation to health. A porous, well underdrained top soil of at least four feet in depth insures dryness and facilities the placing of foundations and the laying of water mains and sewer pipes. Such a soil also is an advantage in growing trees, shrubs and grass plots, which are a decided adjunct to making the community attractive.Enviroment. The contiguous territory should afford no unwholesome sur¬roundings such as swamps Or accumulations of stagnant water.General Considerations. The water supply to be provided and the method of disposal of wastes influence to a certain extent the location of the camp or town-site. The means of supplying water, whether by gravity or by pupping, and the disposal of sewage, whether by outfall, system, sewage disposal system through septic tanks, broad irrigation or filter beds, or cesspools will govern the location of the site topographically in relation to source of water and point of disposal of sewage.* This article was prepared as part of the paper ""Use and Supply of Water for the Oil-Shale Industry"" by J. J. Jakowsky, to be published by the Department of Metallurgical Research, University of Utah, in cooperation with the United States Bureau of Mines."

Jul 1, 1921

By J. P. Hansen

Reducibility tests were run by the Bureau of Mines on an open hearth lump ore and four groups of pellets whose smelting characteristics had been deter-mined previously in the Bureau's experimental blast furnace. When reduction data from various tests were plotted on specially prepared paper l-(l-percent reduction/100)1/3 against time, the plots were linear. The iron-wustite inter-face therefore advances at a constant rate. The rate of the interface advance in mm/min was used as a reducibility index. The reducibility index measured at 900° C, using 0.45 cu ft hydrogen per minute varied inversely with the surface area of the sample. Even with carefully controlled surface areas, how-ever, duplicate reducibility indices varied considerably. When enough tests were run to give a stable mean, the mean reducibility index did correlate with blast furnace production for the four pellet groups. Results indicated that if the interface speed itself were to be used for correlation with blast furnace production, a sample size of about 180 grams of minus 0.742-plus 0.525-inch particles should be used with a test temperature of 900° C and a flow of 0.45 cu ft hydrogen per minute.

Jan 1, 1966

By R. E. Chaney

This report summarizes the research on the Strategic and Critical Materials Program tasks conducted at the Idaho National Engineering Laboratory (INEL) between May 1984 and April 1985. The work is divided into two areas: 1. Production Technologies - Tasks directed at developing advanced extraction technologies ? Biologically-Assisted Minerals Processing ? Metal/Gas Reactions and Thermal Plasmas ? Dehydration of Aluminum Chloride Hexahydrate (completed). 2. Conservation/Substitution Technologies - Tasks directed toward establishing the technical processing base which will permit the use of advanced materials ? Joining of Rapidly Solidified Alloys (RSA) ? Joining of Silicon Nitride-Based Ceramics ? Nondestructive Evaluation of Ceramic and RSA Joints and Materials ? Substitute Catalytic Materials for Platinum.

Jan 1, 1985

By Michael P. Moore, Christopher J. Rise

"Over the past twenty years, there have been numerous studies which have attempted to correlate the prevalence of Coal Workers' Pneumoconiosis (CWP) with different characteristics of the coal seam. Some investigators have tried to find a relationship, or the lack of a relationship, between the rank of coal seams and the incidence of CWP. Others have attempted to show that there is a positive correlation between the mean mass of respirable dust in the mine atmosphere and the prevalence of CWP. Still others have tried to determine the influence of the quartz content of respirable dust on the incidence of CWP. Unfortunately, many of these different investigations have conflicting conclusions.One area of research with conflicting conclusions deals with the relationship between the rank of the coal and the incidence of CWP. For example, an inves¬tigation conducted in Pennsylvania and West Virginia coal mines concluded that the prevalence of CWP increases with an increase in coal rank (1). A study in Great Britain also observed a close relationship between the rank of coal and the prevalence of CWP (2). However, another study involving 312 Appalachian coal miners concluded that the association between coal rank and CWP might be fortuitous and that other factors may be more important (3). In addition, an investigation involving 2,600 miners during a period of twenty years in Great Britain established that there is only a weak correlation between the prevalence of CWP and the rank of the coal (4). Consequently, it appears that there is still uncertainty as to whether or not the rank of the coal seam has an influence on the development of CWP.Another area of investigation concerns the relationship between the mean mass of respirable dust present in the mine atmosphere and the prevalence of CWP. A study involving 4,122 miners over a period of ten years in Great Britain noted a high correlation between the mean mass of respirable dust and the incidence of CWP (5). Another investigation involving 3,154 British face workers con¬cluded that the overall mass of respirable dust is the factor most closely related to the ten-year attack rate of CWP (6). However, a study conducted in thirty-one mines in the United States concluded that it is doubtful that the quantity of respirable dust alone is responsible for the difference in the prevalence of CWP (7). Even though there are conflicting conclusions, there are many more investigators who confirm, rather than deny, the relationship between the mean mass of respirable dust and the development of CWP.The third subject of investigation is the role of quartz in the incidence of CWP. For example, two studies in Great Britain concluded that the quartz content in coal mine dust has no relationship to the prevalence of CWP (8,9). But a study involving 312 Appalachian coal miners revealed that the level of exposure to free silica plays an important role in the development of CWP (10). Once again, the conclusions reached by different researchers are conflicting.Probably the most important factor in the discrepancy among the studies is the variability among different coal mines. A mine operating in an inherently ""dusty"" seam may have a low concentration of respirable dust while a mine operating in a less dusty seam may have a high concentration of respirable dust. This discrepancy is a result of variables such as the effectiveness of ventilation or the efficiency of the water sprays. Consequently, it is very difficult to compare the dustiness of different coal seams by in-mine measurements of the respirable dust concentration. A laboratory test would more accurately characterize a coal seam according to its respirable dust production."

Jan 1, 1988

By J. C. Duchon

The use of extended workdays or compressed workweeks (regular shift lengths exceeding 8 h) is attracting growing interest in many industries using continuous operations. While extended workdays promise increased worker satisfaction due to more days off, including weekends and holidays, there are legitimate concerns about the potential effects on the health and safety of such a schedule. The U.S. Bureau of Mines (USBM) conducted a study at a Canadian underground copper, lead, and zinc mining operation that was designed to study the safety and performance implications of extended workdays. Measures were taken before and after a change from the old 8-h continuous schedule to the new 12-h continuous schedule, including behavioral performance measures to analyze perceptual-motor changes, continuous heart-rate monitoring and aerobic capacity to measure physical fatigue, a variety of self-report questionnaires to measure perceived adaption and satisfaction with the new schedule, and pulmonary-respiratory measures to examine air contaminant exposure. Based upon the overall acceptance of the new schedule by the workers and lack of change in fatigue-sensitive behavioral and physiological performance measures, this study recommends that the mine retain the 12-h schedule. However, certain precautionary measures are suggested to insure the safety of the workers.

Jan 1, 2010

By J. H. Johnson

The report references reports and publications from 1975 to the present related to diesel underground mine air quality research undertaken by Michigan Technological University. Research results obtained on this contract are summarized in 5 different sections as follows: Section 1 - Development of a Systematic Approach to Monitoring, Data Analysis, and Interpretation for Diesel Mine Air Quality Control, Section 2 - Experimental Evaluation of LHD On-Board Air Quality Control Systems, Section 3 - Development of a Portable Self-Contained LHD Tailpipe Emissions Measurement Apparatus for NO , N0, CO, CO , and Particulate Matter, Section 4 Quantitative Analysis of Diesel and Coal particulate Matter by Laser Raman Spectro¬scopy and Section 5 - Development and Application to Detector Tubes of a Laboratory Method to Assess Accuracy of Occupational Diesel Pollutant Concentration Measurements.

Jan 1, 1985