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By H. P. Greenwald

[For sarno years past the Safety in Minbr. Resaarch J30ard of Great Bri tr-dn ha:1 been making ar.. intensive Gearch for, traterials that \.'ould be 1!\ore ef-ficient than rock dust and th t 'could l1eplace it Jholly or in El:}rt as a muans of prevEll'ltine the propa 'tion' of 'c63.1~dust exnlosions in. mines21 In the course of this \o.'ork several rock c.ur--ts md numerous inorganic compounds I,/ere tested. The result w place incombus.ti ble substFlnces in two main groups~ (1) r.:ho se who sa effect' in suppre aeina Jlihe cor.lbustion of coal dUDt i 0 pro-]

Jan 1, 1940

By F. E. Walker, S. J. Aresco, J. B. Janus

The Bureau of Mines has been active in promoting the purchase of coal for Government use under specifications that define the requirements in terms of heating value of the coal , expressed in British thermal units , and the composition as shown by proximate analyses . To these , when required , are added the ash- softening temperature , the free - swelling index , and the Hardgrove grindability index . Under most of these specification contracts the bidders guarantee the quality of the coal , and that guaranteed by the successful bidder becomes the standard of his contract . The deliveries are sampled in accordance with instructions 4/ issued by the Bureau of Mines ; the samples are analyzed in the Bureau laboratory to determine whether the coal is of the quality guaranteed by the contractor and , if it is not , a price adjustment is made . Analyses of the delivered coal and tipple samples ( samples collected at mine tipples as coal is being loaded into railroad cars or trucks ) provide valuable data for use in evaluating future bids . In addition , the continuous sampling of coal as delivered is a check on the practical results obtained in burning the coal . The Government purchased approximately 5 million tons of coal in fiscal year 1962. In connection with these purchases , the Bureau analyzed 7,114 samples . These are published ( table 1 ) for the use of Government officials and the public . A series of publications has been completed on coal analyses by States or , where production is small in any one State , by groups of adjacent States . In addition to analytical data showing composition and quality of coals of the States , the publications contain brief descriptions

Jan 1, 1963

By Manuel Gomez

Published experimental coke data from a pilot plant slot-type oven were examined by statistical regression analysis. Quantitative relationships were found to exist between the coking rate, bulk density, and fine grinding of the coal, sole-oven expansion, volatile matter, moisture, ash, and carbon con-tent of the coal and coke parameters indicative of size and strength. Regression equations developed from coke data were shown to yield computed values that were in good agreement with experimental results for 11 coke properties. Prediction equations developed were evaluated with an independent set of data. Present results indicate that the variables cited undergo much interaction and the sum of these interactions determines coke size and strength.

Jan 1, 1967

By Paul M. Tyler

The colony of French Guiana ( or Cayenne ) is administered by a governor , assisted by a privy council of five members . A council - general of 16 members is elected by French citizens resident in Guiana, and the colony is represented 3 in the French parliament by one deputy . The area is about 34,740 square miles . French Guiana is the largest gold producer of the French colonies , producing nearly $ 1,000,000 worth annually . Considerable prospecting has been done on the bauxite deposits , which are extensive . Copper , iron , lead , and 4 mercury deposits are also reported . In 1931 , 10,000 prospectors for gold were reported as working . The French Government is taking an active interest and has sent a committee of mining experts to explore the region ; no permits are to be issued to individual prospectors while the committee is in the colony . Plans for development of mining industry include consideration of 4,500 convicts and 2,500 natives already in the colony and available for labor .

Apr 1, 1933

By Kenneth L. Rubow, Virgil A. Marple, Bruce K. Cantrell

"In a cooperative study by the University of Minnesota and the U.S. Bureau of Mines, diesel exhaust and mineral dust concentrations have been measured for aerosols generated in the laboratory and in five underground coal mines. Three mines utilized diesel-powered haulage equipment and two used all-electric equipment. Two source apportionment techniques have been applied to differentiate between the mineral dust and diesel exhaust aerosol concentrations measured. The first technique, using a micro-orifice, uniform deposit impactor (MOUDI) for size selective sampling, is based on modeling aerosol size and the premise that the diesel exhaust portion of the aerosol is predominantly submicron and the mineral dust portion is mostly greater that one micrometer in size. The second technique, Chemical Mass Balance (CMB) modeling, was used to referee the analysis of diesel exhaust and mineral dust aerosol concentrations from the size selective sampling results.The MOUDI size distribution data were modeled to obtain parameters describing the fine and course fractions of the sampled aerosol and to estimate the contributions to each mode from both mineral dust and diesel exhaust aerosol sources. The results showed the size distribution of the mixed aerosols exhibited two definite modes with the minimum between the modes occurring at 0.8 µm. Less than 5 pct of the coal mine diesel aerosol was found in the coarse size fraction. CMB analysis confirms the original premise for using aerosol size to separate diesel exhaust and mineral dust aerosol during sampling.Based on the results from the size selective sampling, a personal diesel aerosol sampler has been developed for measuring diesel aerosol mass concentrations. Th.is sampler uses an inertial impactor to size separate the respirable aerosol at 0.8 µm. All material less than 0.8 µm is collected on an after filter for subsequent gravimetric analysis."

Jan 1, 1990

By C. A. Herbert

This paper sets forth the hazards of accumulations of explosive mixtures of methane and air due to inadequate ventilation, the causes of which are discussed as follows: 1. Lack of well-maintained air courses. 2. Air losses due to leaky stoppings, trap doors, and overcasts. 3. Faulty mining methods. 4. Poor supervision. A modified plan of room-and-pillar panel mine development is suggested, which, it is believed, will eliminate many off the hazards of gas accumulations inherent in the present method of mine development. It is also suggested that some water-proofing agent be used on the roof of permanent air-course entries in conjunction with roof bolting to eliminate the detrimental effect of the moisture-laden atmosphere during summer and thus prevent serious roof falls.

Jan 1, 1953

By J. W. Miller

From 1889, when the first railroad shipments of coal were made from McDowell County, W. Va., until today, the coals produced from the New River and Pocahontas groups have had a good reputation as premium low-volatile coals. Although there has been a large production from the Pocahontas No. 3 and. Pocahontas No. 4 beds, considerable reserves remain. This Bureau of Mines publication is one of a series appraising the Nation's coking-coal reserves by presenting data on the basis of which the practicability of upgrading marginal deposits to metallurgical standards can be determined. This study of the preparation characteristics of McDowell County coals is the second of the series to be undertaken in West Virginia. The Pocahontas No. 3 and No, 4 beds have not been included because their washing characteristics are well known.

Jan 1, 1954

By A. T. Coumbe

During 1953-55, 31,105 miles of pipe for transporting crude petroleum and refined products was laid in the United States, a total slightly below that of the prior 3-year period, according to data compiled by the Bureau of Mines, United States Department of the Interior. The added mileage consisted of 22,571 miles of new pipe, representing about 2,163,807 tons of steel, plus 8,534 miles of secondhand pipe, equivalent to about 419,849 additional tons of steel. During the 3-year period, 13,069 miles of pipe was taken up. By January 1, 1956, the Nation had 188,540 miles of pipeline, an 11-percent gain over the 1952 total of 170,504 miles. The greater use of larger diameter pipelines indicated in recent surveys has continued, as the mileage for sizes 12 inches and over increased from 13 percent of the total mileage at the close of 1952 to 16 percent 3 years later. Crude-oil trunklines 12 inches and over in diameter gained 24 percent during 1953-55, and these larger lines represented 30 percent of the total mileage compared with 25 percent at the close of 1952. Furthermore, the mileage for crude-oil lines less than 12 inches in diameter declined 2 percent and made up only 70 percent of the 1955 total against 75 percent n the previous survey. Product Lines 8 inches and over increased 43 percent from 1952 through 1955 and composed 70 percent of the total mileage compared with 66 percent in 1952.

Jan 1, 1956

By J. E. Chilton

The U.S. Bureau of Mines has developed an intrinsically safe carbon monoxide (CO) monitoring system for mines by coupling a fiber-optic data telemetry (FODT) system with a prototype electro-chemical CO monitor. The CO monitoring system can be used in a coal mine as one component of an early fire warning system. This system may be used in belt haulage entries when the entries are used for supplying ventilation air to working places. The FODT accepts a 0.1-to 1.1-V analog signal from the monitor and converts it to pulses (0 to 5 V) at frequencies from 1.1 to 11 kHz that drive a light-emitting diode (LED). An electrically nonconducting fiber-optic cable carries the LED signal to a remote receiver. The receiver analyzes the incoming light signal and displays the measured CO concentration in parts per million. This report discusses the performance of the FODT system and characteristics of the CO monitor such as response times, linearity, and temperature and pressure effects.

Jan 1, 2010

By B. C. Parks

This is the first of a series of reports on the relation between microscopic composition and chemical and physical properties of banded bituminous coals. It describes the relation between microscopic composition and behavior during thermal decomposition of a heterogeneous, high-volatile A bituminous coal from the Chilton bed in West Virginia. The standard free-swelling test was used as a simple means of studying the effect of heat on the coal. Although swelling indexes are not precise indicators of coal behavior in the coke oven and have limited value in caking investigations, they are reliable for predicting expansion of coal in a fuel bed and have practical value in the study of fuels. The swelling test also supplements other useful laboratory tests for determining the plastic and expansion properties of coal.

Jan 1, 1957

By O. C. Blade

This report on the properties of motor fuels sold through service stations in the United states was made in accordance with a cooperative agreement between the American Petroleum Institute and the Bureau of Mines of the United states Department of the Interior. This paper is a continuation of a series made in cooperation with the Coordinating Fuel Research (CFR) Committee of the Coordinating Research Council (CRC), Inc. The first of this series of reports presented data on motor gaso1ines sold during the winter of 1935-36, and succeeding reports described motor gasolines sold during the summers and winters to and including the summer of 1941.3/ No reports were made on motor gasolines sold during the winter of 1941-42 and during the summer of 1942. However, starting with the winter of 1942-43, the semiannual reports were resumed

Jan 1, 1948

By D. R. Dolinar, J. Pablic, D. C. Oyler, T. P. Mucho

At a mine in central PA, high horizontal stresses have caused long running roof falls resulting in hazardous conditions for the miners and the premature abandonment of panels. Because of these conditions, the mine requested assistance of the National Institute for Occupational Safety and Health (NIOSH) in utilizing the 'advance and relieve method to mitigate the affects of horizontal stress on the mine roof. "Advance and relieve" mining involves the removal of a pillar or a portion of a pillar during development, thereby creating a cave along one side of the panel. Following cave development, the horizontal stress is relieved over the workings adjacent to the cave in the active panel. The mine has used this system in three panels with a significant reduction in stress damage and no large roof falls.

By T. F. Tomb

Past experience has shown that the penetration characteristics of the 10-mm nylon cyclone used on approved personal sampling equipment are significantly different from those determined in the laboratory using a nonpulsating flow source. The Bureau of Mines has developed and recommended a modification to presently approved equipment that will alleviate this difference. However, as a result of this modification, a new relationship for converting respirable dust concentrations measured with approved personal sampling equipment to equivalent concentrations as measured with an MRE instrument will have to be established. This Bureau of Mines report describes the underground sampling program conducted to establish a new factor for converting respirable dust concentrations measured with personal sampling equipment, modified with a recommended pulsation damping device, to an equivalent concentration as measured with an MRE gravimetric dust sampler.

Jan 1, 1973

By Anthony T. Iannacchione

The Bureau of Mines developed data on the methane content of the Hartshorne coalbed, Haskell and Le Flore Counties, Okla. The methane content is calculated to be between 1.1 and 1.5 trillion cubic feet, based on an estimate of total coal in place of 2.4 to 3.2 billion short tons. Methane increases with depth, but the rate of increase decreases with greater depths. Degasification in advance of mining is recommended for all mines operating at depths greater than 500 feet to reduce hazards and methane explosions, decrease mine ventilation costs, and conserve the natural gas that would be otherwise wasted.

Jan 1, 1979

By Foster Fraas

Almost all minerals show irreversible changes in electrical conductivity after heating in the temperature range 100° to 800° C. This effect can be detected with only a limited number of minerals with the standard ionizing-electrode-type separator, which differentiates between nonconductors and conductors in the single-particle resistivity range of 1011 to 1013 ohms. Tests outside this range with other type separators, such as the static field type, increase the number of minerals with which the effect can be detected to almost all that were tested. Irreversibility may be the result of an alteration of adsorption layers, volatilization of surface cations or anions, or an oxidation or reduction. One example is limonite, which decomposes to hematite and passes through two minima and two maxima in conductivity in the temperature range 100° to 900° C.

Jan 1, 1959

By Eugene T. Sheridan

This circular presents data on individual plants of the fuel-briquet and packaged-fuel industries that responded to the Bureau of Mines annual economic survey and reported production for 1959. The companies named herein represent virtually all producers of processed fuels of mineral origin. A few small companies may not have been canvassed or failed to respond, however, as some plants operate intermittently, and the survey is voluntary. No consideration was given to size of the plant and all plants that reported commercial production were included. Specifically excluded were plants that manufactured briquets from wood charcoal. Fuel briquets and packaged fuel are manufactured solid fuels, fabricated from fine-sized mineral fuels by mixing with binders and compressing into small individual shapes. Briquets usually are produced as small, pillow-shaped pieces, 2 to 4 inches long, weighing 2 to 4 ounces. Packaged fuel consists of 3- to 4-inch cubes, 6 or 8 of which are wrapped in heavy kraft paper to form a package weighing 10 to 15 pounds. The overall size of a popular package is 10-112 x 7 x 3-1/2 inches. Briquets are durable, may be stored outdoors, and shipped and used as bulk fuel. Packaged fuel is fragile, and must be stored indoors to keep it from deteriorating. Whereas briquets are consumed in many areas as a general residential fuel, packaged fuel is more of a specialty item, used at times as a supplement to other fuels. Package fuel is burned without removing the paper and referred to as the "white-glove" fuel.

Jan 1, 1960

By O. C. Blade

This report on the properties of motor fuels sold through service stations In the United States was made In accordance with a cooperative agreement between the American Petroleum Institute and the Bureau of Mines of the United States Department of the Interior. By agreement with the American Petroleum Institute, identification of the items Is confidential. 1t presents analytical data for 4, 802 samples, representing the products of 117 companies. The samples were collected during December 1954 and January and February 1955. As in previous surveys, the gasolines covered 6y this survey Include those from both large and small suppliers. The data were obtained by laboratories of various refiners, motor manufacturers, and chemical companies and submitted to the Bureau of Mines for compilation, A list of the National Motor-Gasoline Survey reports published during the past 10 years is given on page 5.

Jan 1, 1955

By J. E. Hamak

This publication contains analyses and related source data for 162 natural gas samples from 15 states and 4 foreign countries. Of the total samples, 154 were collected during calendar year 1992. The remainder were collected earlier, but releases granting permission to publish were not received until 1992. None of the analyses have been previously published in annual reports. All samples were obtained and analyzed as part of U.S. Department of the Interior, 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, 1993

By Carlton E. Brown

Impinger dust-counting methods are used by industrial hygienists for determining the number concentration of unhygienic siliceous dusts in industrial atmospheres. Various statements have been made regarding the size of the smallest particles revealed by the microscopic employed in such determinations. Published data on the subject are quite limited. This report presents information on the size of the smallest particles revealed by light-field and dark-field techniques applied to impinger and electric precipitator samples collected from experimentally established aerosols of silica dust and bituminous-coal dust. Size distribution and number concentration of particles of the various sizes in the aerosols were determined from samples collected by thermal precipitation simultaneously with the impinger and electric precipitator samples. The size of the smallest silica and bituminous-coal dust particles determined in the light-field counting method used was about 1./1, . There was relatively little variation in the values from 8 impinger and 33 A.-C. precipitator samples of silica dust and 13 impinger and 13 A.-C. precipitator samples of coal dust. The coefficients of variation of the values from the four sets of determinations were low, ranging from ± 7.7 to t 10 percent. This size of 1,14 is close to the limit of resolution of the microscopic method used and to various previously suggested values. The size of the particles determined in the dark-field counting method used was smaller than the size (about 0.28A ) of the smallest particles determined in the light-field, oil-immersion method used for the thermal precipitator samples.

Jan 1, 1951

By William O. Vanderburg

Some mines after passing through the prospecting stage and becoming sizable enterprises still adhere to the development program of the prospect, extending their workings without definite plans. In mining operations where definite structural conditions do not exist, a prearranged layout of mine development is not feasible; but where exploration and preliminary development have indicated the extent and probable limits within which the ore is expected, careful planning of development will result in a lowering of mining costs and a consequent increase is profits. A lack of definite plane for laying out mine workings is one of the contributory factors to unnecessarily high costs. Although this paper deals primarily with the influence of level spacing on mining costs, still other phases of mine development, such as the proper spacing of ore chutes and raises, can be analyzed on a cost basis in a similar manner, as shown herein. LEVEL SPACING The problem of establishing a new level or levels in order to exploit steeply dioping ore deposits and prospect the ground at depth recurs at intervals during the active life of mines. Driving levels is largely "dead work" and therefore costly. By the judicious selection of the proper level interval after balancing the opposing factors involved in the problem, a considerable saving in mining costs can be effected. Although much has been written in regard to the various methods employed in ore extraction, mining literature is still incomplete in regard to the factors-influencing level spacing at various mines. Level spacing involves procedures not lending themselves readily to description, and, moreover, it is a phase of mining operations that is apt to escape criticism, because only those in close contact with the operations are equipped with the necessary familiarity with the conditions to pass judgment.

Jan 1, 1932