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By Gary P. Sames

The Bureau of Mines recently initiated a study of geologic features that contribute to roof instability in western U.S. underground coal mines. The purpose of the study is to provide information for use in ground control planning and safety hazard reduction in that region, where mining activity has been increasing. Hazardous geologic conditions were surveyed in selected underground coal mines in Utah and Colorado, and both depositional and structural features were identified as potential ground hazards. Although the conditions found do not differ in kind from hazardous geologic conditions in the Eastern United States, they do differ in intensity of occurrence and relative importance. Three depositional features dominate where unstable roof occurs in western underground coal mines: paleochannel deposits, crevasse splay deposits, and flood basin deposits. Three structural features identified as hazardous, but not so widespread or common as the depositional hazards, are faulting, jointing, and igneous intrusions. This survey establishes a foundation for future studies aimed at reducing and preventing ground control accidents in western coal mines.

Jan 1, 1988

By Richard S. Fowkes

Advanced technology, including automation and computerized information systems, is being adopted in mining at an ever-increasing rate to improve safety and productivity and to decrease overall costs. This U.S. Bureau of Mines report focuses on the human factors issues related to advanced technology. Among the significant facts discovered were the following: Experts studying tile design adoption, and implementation of new technology have stated repeatedly that human factors specialists should be involved from the early planning stages, through design and fabrication, and up to and during production, since human factors has been consistently identified as the biggest obstacle to the efficient utilization of new technology. Also, middle management is generally the greatest obstacle to the adoption of advanced technology, this technology can give rise to worker alienation, boredom, stress, job insecurity, and a sense of isolation; training most of the present work force is more cost effective than hiring new workers; workers are willing to accept new technology if they are given a voice in its implementation; the social and the technical systems should be jointly optimized; and with the intro¬duction of advanced technology, the cognitive or mental, rather than the physical, aspects of human-machine interaction must be emphasized.

Jan 1, 1994

By H. F. Yancey

The development, manufacture, and sale of small coal stokers suitable for domestic use has provided a new industry in the United States at a time when badly needed. Sales of domestic stokers have doubled each year for the past 4 rears, until in 1936 probably more than 90,000 such units were put into use. According to reports of the Bureau of the Census 79,543 residential stokers were sold in the first 10 months of 1937 by 109 manufacturers. This rapid expansion has made itself felt in the coal-mining industry. The smaller sizes of coal, either in a sized or slack condition, are in greater demand; as a result, preparation practices at the mines have had to be revised so that, in many instances, lump coal is being crushed to meet the demand for stoker coal. This situation in turn has necessarily resulted in a realignment of price schedules for the different sizes. One of the first underfeed stokers small enough for domestic use was developed at Seattle, Wash., in 1912; in 1916, a small overfeed stoker was developed at Seattle. These two types are generally considered to represent the beginning of the present domestic stoker industry in the United States. A careful inquiry as to the number of domestic stokers now installed in the Seattle area, made by C. R. Pate, who was detailed to this duty by the Works Progress Administration, indicated that probably 7,000 domestic stokers are being used in this area for residential heating. Most of these stokers axe of the overfeed type, although in the past 2 years the underfeed type has made rapid gains.

Jan 1, 1938

By H. F. Yancey

The development, manufacture, and sale of small coal stokers suitable for domestic use has provided a new industry in the United States at a time when badly needed. Sales of domestic stokers have doubled each year for the past 4 years, until in 1936 probably more than 80,000 such units were put into use, According to reports of the Bureau of the Census 75,543 residential stokers mere sold in the first 10 months of 1937 by 108 manufacturers. This rapid expansion has made itself felt in the coal-mining, industry. The smaller sizes of coal, either in a sized or slack condition, are in greater demand; as a result, preparation practices at the mines have had to be revised so that, in many instances, lump coal is being crushed to meet the demand for stoker coal. This situation in turn has necessarily resulted in a realignment of price schedules for the different sizes. One of the first underfeed stokers small enough for domestic use was developed at Seattle, Wash., in 1912 in 1916, a small overfeed stoker was developed at Seattle. These two types are generally considered to represent the beginning of tie present domestic stoker industry in the United States. A careful inquiry as to the number of domestic stokers now installed in the Seattle area, made by C. R. Pate, who was detailed to this duty by the Works Progress Administration, indicated that probably 7,000 domestic stokers are being used in this area for residential heating. Most of these stokers axe of the overfeed type, although in the past 2 years the underfeed type has made rapid gains.

Jan 1, 1938

By Frank C. Morris

It is generally recognized that the productivity and ultimate recovery of an oil well may be reduced as a result of reduction in permeability of the sand at the well bore by invasion of filtrates and clay particles from drilling fluids. As a means of determining whether a sand has been "damaged" from these sources, several investigators2 3 4 5/ have developed methods of analysis based on the rate of increase in bottom-hole pressure while a well is shut in. Because of growing recognition of the importance of completion practices as related to the quantity of oil that may be recovered from wells, the Bureau of Mines has studied completion practices in California and the Midcontinent area. Well-interference and pressure-buildup tests were completed Ear seven wells in the Scurry Reef field to determine the effective permeability in the reservoir.6/ Also, a study was made of the pressure-decline curves obtained from 35 water-input wells in 5 different production areas of northeastern Oklahoma and eastern Kansas.7/

Jan 1, 1957

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 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 B. H. Eccleston

The effect upon automobile emissions in changing from leaded to lead-free gasolines was studied in experiments by the Bureau of Mines in cooperation with the American Petroleum Institute. Typical U.S. leaded gasolines and prototype lead-free gasolines of comparable octane quality were used in eight vehicles operated to simulate city driving. The experiments were run at 70° and 95° F. Exhaust and evaporative emissions were measured and the photochemical effect of the emissions was experimentally observed in an artificial smog chamber. Results of the study reveal the manner and degree in which the changes in fuel composition alter the amount and characteristics of both exhaust and evaporative emissions. Briefly, it is shown that the compositional differences between leaded and prototype lead-free fuels resulted in higher photo-chemical pollution potential of the emissions from the lead-free fuels. The effect is attributed to the photochemical characteristics of high-octane fuel components that are used in greater quantity in the lead-free fuels.

Jan 1, 1970

By G. V. Sullivan

The Bureau of Mines conducted preliminary beneficiation studies of a gold-bearing graphitic schist from Blue Hill, Tallapoosa County, Ala. The average analysis of the material was 0.08 oz/ton gold. Tabling of minus 35-mesh material recovered 83 to 94 percent of the gold at grades of 6.925 to 2.165 oz/ton, respectively. A combination of jigging and tabling resulted in a concentrate assaying 24.3 oz/ton gold and contained 87 percent of the total gold. Treatment of the material by jigging, tabling, and amalgamation recovered 86.5 percent of the gold.

Jan 1, 1969

By H. E. Blake

An evaluation was made to determine the economics of utilizing waste fluosilicic acid for production of (1) calcium fluoride, and (2) anhydrous hydro-gen fluoride. Two versions of each process were considered and compared. The evaluation showed that both products could be produced and marketed competitively. Lowest estimated product sales prices required to yield a 25-percent return on investment before taxes (discounted cash flow basis) was $339.34 per ton of hydrogen fluoride and $48.64 per ton of calcium fluoride.

Jan 1, 1971

By Phillip Allender, Wolf Karo, Knox Van Dyke, Lixin Wu, Ali Ardekani, Jorge Garcia, Jaime Gutierrez

"We report that two different micropolystyrene round beads linked to either luminol or lucigenin have been developed. The 1-µ.m-diameter beads arc useful reagents that allow one to perform chemiluminescent (light producing) phagoeytic reactions without opsonization. It is known that luminol reacts with peroxidases (e.g., myeloperoxidase) while lucigenin reacts mainly with superoxide anion. Luminol and lucigenin beads produce cellular chemiluminescence (CL) with neutrophils, macrophages, monocytes, and differentiated human promyelocytic leukemic cells (HL60). When myeloperoxidase (MPO) is present luminol beads evoke higher CL from neutrophils, but when little or no MPO is present, lucigenin beads produce higher amounts of light. Lucigenin beads appear to be active inside these cells where unbound lucigenin does not enter freely.INTRODUCTIONA variety of cells, e.g., neutrophils (Ns) and macrophages (Ms), can engulf foreign particles (1). This engulfing or phagocytic activity is used by the body to kill bacteria and to eliminate foreign particles such as respirable dusts, e.g., coal, silica, or cotton. The neutrophil engulfs or phagocytizes bacteria which are coated with plasma antibodies and/or complement proteins (Fig. 1). The coating or opsonization allows the neutrophil to recognize foreign substances. Usually the absence of opsonization prevents the cell's recognition of a foreign particle and the particle is not phagocytized. Macrophages, particularly the alveolar Oung) cells, do not require opsonization for phagocytosis. Ms should not be selective toward individual dusts because they serve a major role in eliminating a variety of these.Particle size can also be a factor. Usually a particle with a diameter of 0.5-5 µ.m is considered in the respirable range. Larger particles are trapped before they reach the alveoli Oung spaces where oxygen exchange with blood occurs), ·and smaller particles do not generally settle, and are not engulfed by macrophages (2). Tabato and Ikada (3) found that maximal phagocytosis of microspheres takes place when their diameter is in the range of 1.0 to 2.0 µ.m. In addition, they found that beads with hydrophobic surfaces were more readily phagocytized than hydrophilic surfaces."

Jan 1, 1990

By Floyd R. Hertweck

The helium resources of the United States were estimated by the Bureau of Mines to be 1,037 Bcf as of January 1, 1981. These resources are divided into four categories, in decreasing degree of assurance of their existence: (1) helium in storage and in measured natural gas reserves, which totals 211 Bcf, (2) helium in indicated natural gas resources, which is estimated at 207 Bcf, (3) helium in hypothetical natural gas resources, which is estimated to be 318 Bcf, and (4) helium in speculative natural gas resources, which makes up the remaining 301 Bcf. These helium resources are further divided into depleting, nondepleting, and stored classifications, The depleting resources are those associated with natural gasfields that are, or will be, produced for the natural gas they contain. All of the helium in undiscovered (hypothetical and speculative) natural gas resources is included in this classification. These depleting resources are estimated to contain 897 Bcf of the total helium resource base. Nondepleting resources are those in shut-in, abandoned, or otherwise nonproducing natural gasfields. Helium resources contained in nondepleting natural gas resources are estimated to total 100 Bcf. There is 40 Bcf of helium in storage in the Federal Government-owned Cliffside Gas Field near Amarillo, Tex.

Jan 1, 1983

By Joseph J. Wallace

1. The investigation shows that there are two coal beds of major importance in Perry County from the standpoint of present production -Flag and Fire Clay -and two beds of minor importance -Haddix and Hindman. The Flag and Fire Clay beds contain the largest remaining known reserves. 2. Known measured and indicated reserves in all beds, based on a minimum thickness of 14 inches and 1,800 tons per acre-foot of coal in place, are estimated at 840 million short tons as of January 1, 1954. Of this total, 720 million short tons is in beds 28 inches and more thick. Areas in each bed were omitted from the estimate because available data relative to the bed characteristics are too meager for making an estimate that conforms with the definitions of measured and indicated coal adopted for this study. Should future drilling or development prove reserves in these areas, these should be added to the total estimated reserves.

Jan 1, 1954

By H. D. Hess

This report presents the results of laboratory mineral evaluations conducted by the federal Bureau of Mines under the joint sponsorship of the U.S. Atomic Energy Commission (AEC) and the Bureau a! Ships, U. S. Department of the Navy. The major purpose of this investigation was to examine and evaluate zirconium minerals representing sizeable deposits in an effort to locate com¬mercial sources of high-hafnium ores. Although determination of the hafnium content was the principal objective, each of the zirconium minerals also was analyzed for combined zirconium-hafnium oxide, silica, uranium, thorium, yttrium, and cerium. The general laboratory procedure involved microscopic examination of the test samples, concentration of the hafnium-bearing zirconium mineral by standard laboratory techniques, and analysis of the derived concentrate by quantitative microscopic, chemical, and X-ray spectrographic methods. Of the several hundred samples tested under this program, 147 are discussed in this report, including 94 from domestic occurrences and 53 from widespread foreign sources.

Jan 1, 1962

By Kenneth L. Cashdollar

This report describes three types of optical dust probes that have been designed, built, and tested by the Bureau of Mines. Each of the probes measures dust cloud concentrations by the attentuation of light. The first is a single-path-length probe, the second is a double-path-length probe, and the third is a single-path-length probe that employs jets of air to keep the windows of the light source and detector free from dust coating. The theory of operation and the calibration procedures for each of the probes are described. The results of the Bureaus laboratory, mine, and field tests of the probes are also reported.

Jan 1, 1981

By Margaret R. Egan

A study of the combustion emission products of rigid ventilation ducting was completed by the U.S. Bureau of Mines. The ducting was composed of fiberglass-reinforced polyester resin. Four properties of the ducting were evaluated: (1) propensity to ignite, (2) smoke characteristics, (3) gas emissions, and (4) heat release. Particle sizes, obscuration, optical densities, and production constants for gas and smoke were also calculated. These results provide comprehensive data about the emission products, detectability, and relative hazards of fiberglass-reinforced plastic ducting and other mine combustibles under realistic fire conditions.

Jan 1, 1990

By E. P. Carman

This report is the 20th in a series summarizing Bureau of Mines research and technologic work on coal and related investigations; it is the second4/ to be issued on a calendar-year basis. Previous reports related largely to publications by Bureau authors during the reporting period. This one discusses the publications issued during 1955 and in addition describes briefly the work in progress during the year. Further details on the published work may be found by referring to the publications cited in the footnotes. The Bureau continues to direct its research and technologic work on coal toward safer and more efficient mining, improved preparation, and more effective utilization, with the ultimate twin goals of promoting conservation and insuring that coal will make its maximum contribution to the Nation's industrial capacity. Significant advances toward these goals were made in 1955.

Jan 1, 1957

By B. W. Naugle

The Bureau of Mines investigated the changes that occur in decomposition products when coal is carbonized in a fluidized bed with steam as the fluidizing medium and the vapors are subsequently cracked without condensation in a fluidized bed of high-temperature coke. The coal used was from the High Splint bed, High Splint mine, Harlan County, Ky. Since this coal is agglomerating, it was blended with char. The integrated unit used in this investigation consisted of a 3-inch-diameter fluidized coal carbonizer, a 3.5-inch-diameter cracker containing a bed of high-temperature coke fluidized by the tar vapors and steam from the carbonizer, and gas-cleaning and product-recovery systems. The carbonizer was operated at 485° C and the cracker at 600°, 700°, and 800° C. The process variables investigated were temperature, residence time, and concentration (pound of tar vapors per pound of steam to the cracker) of tar vapors in the cracker. The total tar yields decreased as the temperature of the cracker increased, and at a constant cracker temperature of 600° C the yield of paraffins, acids, aromatics, and olefins in the distillate increased directly with the tar vapor concentration in the cracker. At 700° and 800° C only the acids and aromatics increased with increased concentration. Bases remained essentially constant regardless of the temperature and concentration. Similar results were obtained when the tar from the carbonizer was condensed prior to feeding to the cracker.

Jan 1, 1965

By D. J. MacDonald

The Bureau of Mines has conducted bench-scale investigations leading to the design of an integrated process for producing reactor-grade zir-conium oxide (Zr02) from zircon sand, which avoids the air pollution, water pollution, fire hazard, and odor problems associated with the hexone-thiocyanate process. The integrated process consists of three steps: production of crude zirconyl sulfate solution, solvent extraction, and production of Zr02 from strip liquor. This report describes the solvent extraction step. Multistage, countercurrent liquid-liquid extraction with a tertiary amine in kerosine was used to separate zirconium from a dilute H2S04 solution containing hafnium and other impurities. Process steps de-scribed include extraction from an aqueous feed solution to form a hafnium-contaminated, zirconium-bearing organic-phase solution, scrubbing to separate zirconium from coextracted hafnium, stripping to transfer hafnium-free zirconium into an aqueous strip liquor, chloride-loading to produce a chloride-bearing organic solution, scrubbing with the chloride-loaded organic solution to remove traces of uranium impur-ity from the zirconium-bearing strip liquor, and regeneration to pre-pare the organic solution for reuse. These steps were performed simul-taneously in steady-state, bench-scale experiments. Zirconium recovery of up to 93 pct was achieved. Results of an economic evaluation are included.

Jan 1, 1984

By R. V. Lundquist

This report describes results of tests on the desilication of solutions resulting from the leaching of lime-soda sinters. Desilication was accomplished by heating the solutions in an autoclave. A liquor relatively free of silica was obtained after 30 minutes of heating at 200 p.s.i.g. in the presence of lime. The addition of lime improved desilication, but the rate and efficiency of desilication was effected by the quality of lime used. The optimum quantity of lime for effective desilication was about 6 grams per liter. A lesser quantity gave poorer desilication, and a greater quantity increased the alumina loss without improving desilication. The alumina loss was approximately proportional to the lime added. A complex structure, called artificial noselite in this report, was the only silica bearing compound detected in the desilication precipitate. Other compounds present were Ca(OH)2 (calcium hydroxide), CaCO3 (calcium carbonate), and Ca [A1(OH)6]2 (hydrated tricalcium aluminate). Sodium carbonate in the leach liquor retarded the formation of the calcium aluminate; hence it decreased the alumina lost to the precipitate. The extraction of alumina from aluminum silicate materials by the limestone soda-sinter process has been investigated by the Bureau of Mines for many years. The process consists of the following major operations: Blending the aluminum silicate with limestone and soda ash in such proportions that dicalcium silicate and sodium aluminate are formed on sintering; leaching the sinter in a carbonated caustic solution to extract the soluble alumina; purifying the leach liquor by the precipitation of soluble silica (this precipitate is designated desilication precipitate in this paper); precipitating alumina trihydrate from the purified liquors by carbonating with carbon dioxide gas; and calcining the trihydrate to alumina. Commercial grades of

Jan 1, 1962