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By W. T. Abel

Laboratory tests were conducted with a closed, recycling system to evaluate the effectiveness of solid-in-gas suspensions as heat transport mediums. Micronized graphite in helium or nitrogen was circulated by a centrifugal compressor to determine the feasibility of the method and heat transfer capabilities of the mediums. Suspensions were circulated without plugging or eroding the compressor or piping. At low flowrates and light (0.1 to 0.2 volume-percent) graphite loadings, slightly less power was required to transport a given amount of heat with suspensions than with helium alone. Graphite deposition on the heat exchange surfaces of the cooler decreased the heat transfer effectiveness at higher solids concentration. Efforts to eliminate deposition are described.

Jan 1, 1963

By D. A. Reynolds, J. D. Davis

During early development of the blast furnace, Connellsville coke made entirely from Pittsburgh-bed coal proved to be an excellent fuel. The need for blending coking coals arose as the industry grew and it became necessary to carbonize coals having voking properties inferior to those of Pittsburgh coal Most coals carbonized today in continental Europe and this country are blonded: This practise has improved the quality of coke and permitted the utilization of coals that would yield inferior coke, if carbonized sepa- rately, The depletion of the world's better coking coals, which has been noted by leading coal technologists,2/4/wes accelerated during the recent war and. It is important, therefore, that reserves be evaluated and conserved. In the principal, steel-producing sections of this country, Pocahontas coals have been blended so extensively that the terms "low-volatile coking coal": and. "Pocahontas" have become virtually synonymous. Other low-volatile coals. have been used to manufacture metallurgical coke and will be used more extensively as, the supply of the better known and more accessible Pocahontas coals decreases. Recognizing the need for augmenting the supply of high-rank coking coals, the Bureau of Mines has included both low- and medium-volatile coals in its Survey of the Carbonizing Properties of American Coals, which was started with the cooperation of the American Gas Association in 1929. Twenty coals, 12 of low-volatile and 8 of medium-volatile rank, have been blended with high-volatile A Pittsburgh-bed coal, and five standard low- volatile coals have been blended with various high-volatile coals. Most of the results of carbonization tests of these coals and their blends have been

May 1, 1946

By Vern L. Kegler

This paper is one off a series dealing with mining methods and costs, sponsored and published by the United States bureau of Mines. ACKNOWLEDGMENTS The author acknowledges the, constructive and helpful suggestions and criticism of W. F. Lamoreaux, vice-president, and general manager of the Ducktown Chemical & Iron Co. United States Geological Survey Professional Paper- 139, by W. H. Emmons and F. B. Laney, has been drawn upon for some of the information contained in the paragraphs or history and geology.

Jan 1, 1931

By Donna lynne Anderson

This report documents the status of a laser-based underground guidance system for tracking and controlling the movements of underground mobile mining equipment. This research is part of a multiple project effort at the U.S. Bureau of Mines to increase mine safety and efficiency by developing technology for computer-assisted mining. Guidance systems, which can track and control the movements of underground mining equipment, are essential during computer-assisted mining operations. A continuous mining machine at the Bureau's surface test facility served as the test-bed for initial development and experimentation of this guidance system. Subsequently, a continuous mining machine in an underground mine served as the platform for in-mine experimentation. The first section of this report includes details of the laser sensors, communication network, and computer hardware. The next section includes experimental results, which show the system capable of accurately tracking and controlling the tram maneuvers of a continuous miner underground. The final section discusses conclusions and recommendations.

Jan 1, 2010

By G. S. Rice

This paper describes preliminary tests at the Bureau's Experimental Mine to determine, under conditions that may prevail in a bituminous coal-mine heading, how small a quantity of fire damp may bring coal-dust into suspension and ignite it. The results show that the explosion of as little as 150 cubic feet of an explosive mixture of gas and air containing 9 per cent natural gas may start a disastrous explosion of coal-dust. This is a very small volume, of gas, to cause such a result. Let us suppose that this amount of explosive mixture, as at the face of an entry which was 10 feet wide and the face was overcut to a depth of 6 feet and an upper layer of coal 2.5 feet thick had been removed, the recess so made would have a volume of 150 cubic feet. Furthermore, only 13 cubic feet of pure methane is needed in thin volume to produce this 9 per cent explosive mixture.

Jan 1, 1930

By Frank C. Andreuzzi

The Federal Bureau of Mines conducted a demonstration project to reclaim 125 acres of abandoned strip-mined land in Lackawanna County, Pa., for public recreational, historical, and educational use as a park. The Bureau was involved in the development of the general site plan, and engineered and supervised the basic land rehabilitation. The park's Facilities include outdoor recreational activities, picnic grounds, children's play areas, primitive overnight camping, and winter sports. A major attraction is the Anthracite Museum constructed by the Pennsylvania Historical and Museum Commission The project may serve as a prototype for reclaiming existing and future surface-mined lands.

Jan 1, 1976

By Oliver Bowles

The exingencies of a world war have brought home to the American public, especially the people of the. Eastern States, the urgent need for conserving fuel. Transportation problems in the East have created an unprecedented situation wherein fuel-oil supplies are greatly restricted, and the consequent increase in demand for coal further complicates the problem of transporting and storing that commodity. People should awaken to the need for utilizing every possibly means of conserving to fuel, even to the extent of reducing the temperature in their homes.

Jan 1, 1942

By J. E. Hamak

This publication contains analyses and related source data for 266 natural gas samples from 20 States and 2 foreign countries. None of the analyses have been previously published in annual reports. All samples were obtained and analyzed as part of the U.S. Bureau of Mines investigations of the occurrences of helium in natural gases of countries with free market economies. This survey has been conducted since 1917. The analyses published herein were made by mass spectrometer and chromatograph.

Jan 1, 1992

By Albert W. Deurbrouck

The performance of four sand cones was evaluated by the Bureau of Mines in three preparation plants that utilized cones in various flow schemes. The cone at plant A was a simple two-product one that provided clean coal and refuse. Plant B had two cones; one cone made a primary separation and the other a secondary separation. The primary cone separated salable coal from heavy rejects. The secondary cone separated a low-ash metallurgical coal and an intermediate-ash product suitable for plant fuel or steam markets. In plant C the sand cone was equipped with a middlings draw Which continually removed an intermediate specific-gravity product below the surface of the cone. The three primary separations of raw coal effected between floats and sinks were excellent. The recovery efficiencies for the plus 1/4-inch material ranged from 99.8 to 97.6 percent, the error areas ranged from 19 to 23 square centimeters, and the probable errors in specific gravity ranged from 0.033 to 0.024. The performance data of the two secondary separations varied from excellent in plant B, where the separation was on a par with the primary separations, to somewhat inferior in plant C, where the secondary separation was effected at the middlings draw.

Jan 1, 1965

By L. J. E. Hofer

The Bureau of Mines determined rates of adsorption and desorption of methane as a function of particle size and temperature, using coals from the Pocahontas No.3 seam (lvb) from the Bishop mine of western Virginia, and the Pittsburgh seam (hvab) from the Pursglove No. 15 mine of northern West Virginia. For a given coal sample and temperature, the rate curves for adsorption and desorption are essentially the same when expressed on a fractional approach to equilibrium basis. The rates of adsorption and desorption increased eightfold as the particle size was decreased from 6-8 to 270-325 mesh per inch. The adsorption process appears to be diffusion controlled. Rate of sorption processes increased with increasing temperature; however, the amount adsorbed at equilibrium decreased.

Jan 1, 1966

By D. E. Sullivan

The Minerals Availability Program of the Bureau of Mines conducts cost evaluations of current and potential mineral operations in the United States and foreign countries. The International Mining Cost Indexation System (IMCI) allows data of different time periods within a country to be updated to a common base year for analytical purposes. The IMCI comprises 12 factor cost indexes and an exchange rate series for 96 market economy countries, denominated in both local and U.S. currency. The IMCI for each country contains 12 time series indexes that measure the average annual rate of change in the cost of factor inputs to the mining industry within that country. Mining industry factor cost indexes include wages, plant and equipment, construction and mining materials, power and transportation, and other measures considered to comprise the majority of capital and operating costs. Cost data or proxies are collected in local currency. Index series within each country are constructed separately and indexed on a 1975 base year. The local currency index is converted to a U.S.-dollar-based currency index using an exchange ratio.

Jan 1, 1987

By Jr. Karr

The Bureau of Mines studied the influence of carbonization method, temperature, and carrier gas on the composition of eight different low-temperature tars produced from a Colorado subbituminous coal. A fluidized bed was compared with an entrained bed, temperature was varied from 500° C to 650° C, and external heating using recycle gas as the carrier gas was compared with internal heating using oxygen-containing gas. The entrained bed yielded significantly more m-cresol and m-ethylphenol, indicating that thermodynamic equilibrium was more nearly approached in the system. Increasing the temperature greatly increased the yield of benzenes and naphthalenes, while paraffins, olefins, and total tar acids were reduced. Using oxygen in the carrier gas decreased the yield of low-boiling phenols and increased that of paraffins and olefins at 650° C.

Jan 1, 1966

By L. Y. Sadler

The Bureau of Mines conducted a study Lo determine the loss in weight of silica (Si02) volatilization from low-alumina (A1203) refractories used as hot face liner materials in such process equipment as coal gasifiers, synthesis gas transfer lines, and ammonia plant secondary re-formers. Small specimens of 80-and 40-pct-A1203 brick and 95-pct-SiO2 brick were exposed to steam in high-pressure furnaces at pressures of up to 1,000 psig and temperatures up to 1,400° C for periods ranging up to 120 h. Weight losses from the 40-pct-A1203 brick after 40 h of exposure were highest, 2.75 pet at 1,400° C and 1,000 psig. The rate of weight loss had dropped to near zero after 80 h of exposure at all temperatures. No relationship between total silica content of the specimen and weight loss could be established nor did scanning electron microscopic examination of the specimens before and after exposure identify specific regions (e.g., surface) suffering a disproportionate share of the silica loss. It was concluded that minor silica volatilization is likely to occur, if at all, at temperatures of less than 1,000° C and pressures below 1,000 psig, and that low-alumina refractories should be used as dry-ash coal gasifier hot face linings.

Jan 1, 1986

By D. J. Parker

The oft-repeated expression that the taproot of safety lies in the attitude of the management toward accident-prevention work is indisputable and has become almost an axiom. Trite and somewhat timeworn though the statement may be, it is nevertheless true that the supervisory force must earnestly support a policy of safety and maintain at all times a con¬ siderate regard for the welfare of the employee if that high degree of cooperation of the employee, so vital to the successful prosecution of any safety program, is to be expected. The responsibility for preventing accidents rests upon the management, and in the case of the Spring Canyon Coal Co. such responsibility is recognized and accepted with little or no reservation. This company, aside from the humanitarian aspects involved, believes that safety is good business and not a matter to be treated passively or in a perfunctory manner. The problems with respect to safety that have been met and wholly or partly solved can best be appreciated when some of the natural conditions, adverse and otherwise, existing at this operation are taken into consideration. Mine 1 is about 1 mile north of the town of Spring Canyon, Carbon County, Utah, and is served by both the Denver & Rio Grande Western and Utah Coal Route railways. During the year 1931 the mine produced 312,397 tons, approximately 10 per cent being derived from pillar workings. The normal daily output during the summer months is about 2,000 tons, and during the peak of production in the winter season the daily production varies from 2,500 to 3,000 tons. The number of miners varies from 87 in summer to 220 in winter, and the day men vary in number from 66 in the winter to 45 in the summer; 12 company men are employed the year around. The officers of the company are J. B. Smith, president, San Francisco, California; T. R. Stockett, general manager, Salt Lake City; and G. A. Murphy, superintendent, David Brown, assistant superintendent, and John Sullivan, mine foreman, all of Spring Canyon, Utah.

Dec 1, 1932

By D. F. Scott

The purpose of this study was to determine if miners were at risk from exposures to chemicals used in the mining industry and determine the nature and sources of the illnesses and injuries. The U.S. Mine Safety and Health Administration?s (MSHA) employment and accident, injury and illness database was reviewed. There were 2,705 cases of chemical-related injuries and illnesses reported from 1999 through 2006, involving 66 different chemicals. The main source (cause) of chemical-related cases was acids/alkalis (about 39%). The primary nature (effect) of chemical-related cases was chemical burns (about 57%). The job classification where workers incurred the most chemical-related injuries and illnesses was cleaning plant operator/media operator/boney preparation plant operator/crusher worker (cleaning plant operators are responsible for maintenance of plants, media operators are responsible for handling reagents, boney preparation plant operators oversee removal of ?bone? from coal, and crusher workers use large crushers to break mined material). From 1999 through 2006, the rate of ?nonfatal days lost? and ?no days lost? (resulting from injuries) did not change significantly; however, the rate of illnesses decreased significantly. Chemical burns accounted for a large number of injuries; mining companies should carefully examine their personal protective equipment (PPE) requirements, training methods and safety culture to ensure that their workers are protected.

Jan 1, 2009

By Leonard F. Heising

Domestic production of Metallurgical-grade manganese has contributed such a small percentage of the United States industrial demands that areas known to contain large tonnages of low-grade manganese ore have been investigated by the Bureau of Mines to reduce this country's dependence on foreign ores. A major source of low-grade manganese is the Cuyuna iron range in Minnesota. The entire Cuyuna iron range is covered by an overburden of glacial drift that, in some places, reaches depths of 200 feet or more. Prospecting and exploration must be guided by geophysical methods, drilling results, or projections of exposures found in operating mines because there are no outcrops near the productive parts of the range. Past drilling for the purpose of outlining iron ore generally was confined to the highly oxidized zones. Much of the manganese with which the Bureau of Mines is concerned occurs in thin-bedded unoxidized iron formations, too low in iron content to have been of interest to those seeking commercial iron ore. The primary objective of the core-drilling reported here was to obtain cores of different classes of manganiferous rocks and to determine whether or not the samples were amenable to beneficiation.

Jan 1, 1959

By L. C. IlsLey

"The maintenance of permissible equipment which is tested and inspected at the Pittsburgh Experiment Station of the United States Bureau of Mines is dependent to a surprisng degree upon the voltage at which the equipment is operated. The difficulty of maintaining 500-volt equipment is frequently brought to the bureau's attention, and it is quite possible that if the bureau had appreciated at the beginning the full hazard involved, it would never have undertaken the approval of equipment operating at voltages greater than 250 volts.In this connection, the following statement from State mine inspection departments and other sources are of interest as showing the general feeling in safety organizations with respect to voltages higher than 250. These statements, although obtained as a result of a questionnaire sent cut several years ago, still apply very well to present conditions.A. I have not had time to consider seriously the proposed change from every angle, but looking at it from a standpoint of hazard, feel that the danger would be greatly increased. I have always occupied the position that underground voltage on portable equipment should never exceed 250 volts.High voltage of course would mean smaller transmission lines, which would be more economical and no doubt would require in several instances smaller equipment; notwithstanding, if this statement is true, the writer is still favorable to low voltage on underground portable equipment.B. I believe 500 volts should be the limit on the best equipment ender the best conditions and that the U. S. Bureau of Mines should do all in its power to limit the voltage to 500 volts on permissible equipment, as any increase in voltage means increased hazard.C. I will refer you to a section of our mining law, entitled ""An Act to Regulate the Tine of Electricity in the Mines of the State of ----"" which reads in part, as follows: Trolley wires, or other exposed electrical wires, shall not carry a voltage above 275 volts.You may readily see by this that we are not permitted to operate mining machines under ground in -----, with more than 275 volts at the terminals, except that we are permitted to install transforming stations throughout the mines, after complying with certain regulations at the mine.However, as we have had to date, within the calendar year of 1925, six men electrocuted in the mines of the State, using a voltage of 275 volts, I am of the opinion that if this voltage was increased, the hazard would also be increased in proportion.D. I do not care to make a statement for publication: however, I am referring you to our mining laws. On page 27 and 28 you will find what the laws of -----¬require relative to the installation of electricity in the mines.""Hereafter where electricity is installed no higher than two hundred seventy-five (275) volts shall be used underground, except for transmission, or for application to transformers or other apparata, where the high-voltage circuit is stationary. High-voltage motors, and transformers, shall be installed in suitable chambers, built of fire-proof construction, and well ventilated, and shall not be placed on intake, or between intake and return air courses. All high-voltage lines lines and apparata must be clearly marked, to indicate their danger. Main and distribution switchboards for high voltage shall be made of insulating and incombustible material, such as marble or slate, and to be free of all metallic veins, or of material equivalent thereto. Same shall be installed in a dry place. All switches or other instruments used in connection with high voltage shall be installed on suitable switchboards, with at least a three-foot passageway in front and rear properly floored, and kept looked by a door at each end that can be opened from the inside without a key. With higher than medium voltage, there shall not be any live metal work on the front of switchboard, and the entry circuit must be protected by an oil breaker s"

Apr 1, 1932

By J. A. Cavallaro

This Bureau of Mines report describes the preparation characteristics of 10 coal samples collected from the significant coal-producing mines of Lucas, Mahaska, Marion, Monroe, and Wapello Counties in Iowa, with special emphasis on physical desulfurization. All 10 samples were of high sulfur content as received, ranging from 4.2 to 10.4 percent; the organic sulfur content ranged from 0.8 to 3.8 percent. The pyritic sulfur content of the samples could be appreciably reduced by crushing and washing and provided pyritic sulfur reductions ranging from 36 to 75 percent. Crushing to 3/8-inch top size and removing the sink 1.60 specific gravity material would provide float coal products containing 3.5 to 6.0 percent sulfur. However, these coals could be burned at utility plants utilizing SO2 removal processes with efficiencies ranging from 70 to 88 percent and still be in compliance with the current Federal SO2 emission regulations for stationary sources.

Jan 1, 1973

By J. J. Forbes

"The central rescue station maintained jointly by several mining com¬panies in a district, is gaining in popularity in a large number of mining districts throughout the country. A very efficient first-aid and mine rescue association, with rescue station, is in operation in 'the Globe-Miami, Arizona, district. This association, known as the ""Globe-Miami District Mine Rescue and First-Aid Association""; was organized on January 1, 1918. Due to the effective work of this organization, several incipient mine fires have been extinguished before the fire got under headway and before any severe damage was done.The mine rescue station, which is situated on the highway between the towns of Globe and Miami, Arizona, is centrally located with respect to the various mines in the district. The station was completed, and a full craw em-ployed for conducting it work on January 1, 1920.The directors and other officers of the association are selected from the mine officials whose properties are served by it. It includes seven large metal mining and metallurgical companies in the Globe-Miami district. The names of the companies, together with the number of men employed by each follows.A director is in charge of the station; he performs the executive work, and, is the managing head of all training in first aid and mine rescue. The director is assisted by three station attendants, one of whom takes the morning shift, another, the evening shift, and the third, the night shift. They exchange shifts every two weeks. As three shifts are maintained, an attendant is on duty at all times. He answers emergency calls in case of fires or accidents, assists with the first-aid and mine rescue training, the inspection of the first-aid boxes and supply bases that are located at the various mines, and attends to miscellaneous duties in connection with the operation and maintenance of the station."

Dec 1, 1920

By K. E. Hjelmstad

During an underground mine fire, air can be rapidly depleted of oxygen and contaminated with smoke and toxic fire gases. Any delay in warning miners could have disastrous consequences. Unfortunately, present mine fire alarm systems, such as stench, audible or visual alarms, telephones, and messengers, are often slow, unreliable, and limited in mine area coverage. Recent research by the U.S. Bureau of Mines has demonstrated that ultra low frequency electromagnetic signaling can be used for an underground mine fire alarm. In field tests of prototype equipment at five mines, electromagnetic signals from 630 to 2,000 Hz were transmitted through mine rock for distances as great as 1,645 m to an intrinsically safe receiver. The prototype system uses off-the-shelf components and state-of-the-art technology to insure high reliability and low cost. When utilized, this. technology would enable simultaneous and instantaneous warning of all underground personnel, regardless of their location or work activity, thereby increasing the likelihood of their successfully escaping a mine disaster. This report presents the theoretical basis for through-the-rock ultra low frequency electromagnetic transmission, design of the prototype transmitter and receiver, and the results of in-mine tests of the prototype system.

Jan 1, 2010