Search Documents

By E. J. Gleim

For many years mining men have sought for a portable device that would be direct reading and permit more positive detection of methane than was possible with flame safety lamps, which depended so largely on the training, skill, and personal ability of the user. Through the years, after the discovery that methane contributed to many mine explosions, considerable effort and large sums of money have been expended in searching for and developing instruments that would be practical, and, at the same time, reliable and safe to use. Very early in the history of the Bureau of Mines, some of its engineers were unsuccessful, after many trials, in attempts to develop such an instrument. Commercial firms, however, persisted in research until today a number of instruments are on the market that have proved to be practical in coal-mine service. It is hoped, however, that further research will bring about improvements in accuracy and other desirable features. BUREAU OF MINES STANDARD FOR METHANE DETECTORS The Bureau of Mines recognized the need for establishing minimum requirements on which to base official approval of suitable Instruments. This standard was prepared as Schedule 8. It was revised before being issued in printed form. The revision was published as Schedule 8A in 1920 and was revised on two other occasions. The present edition, known as Schedule BC, was issued October 31, 1935.

Jan 1, 1954

By W. H. Eddy

The Bureau of Mines conducted laboratory batch flotation tests and continuous pilot plant flotation tests on a complex calcareous fluorspar ore from Cave-in-Rock, Ill., to determine the technical feasibility of producing commercial-grade concentrates by the sodium fluoride-calcium lignin sulfonate-fatty acid method of concentrating fluorspar previously developed by the Bureau. The continuous flotation tests, treating about 150 pounds of ore per hour, produced fluorspar concentrates assaying 96.4 percent CaF2; 90 percent of the fluorspar was recovered.

Jan 1, 1967

By J. E. Tiffany, Gaigler. Z. C.

"PREFACEIn presenting this list of permissible explosives and blasting devices, the Bureau of Mines desires to call attention to pages 16 and 21 outlining the conditions in use under which, and only under which, the explosive or blasting device is permissible.In view of a recent publication recounting trade practice favoring the use of a blasting device without stemming, particular emphasis is placed upon condition 4 on page 16 and condition 2 on page 21. An explosive or a blasting device enumerated in the permissible lists of this Bureau is not permissible in use unless it is properly confined with clay or other incombustible stemming.PERMISSIBLE EXPLOSIVES TESTED UNDER SCHEDULE 17CAn active list of permissible explosives was published in December 1937 as part of Bureau of Mines Report of Investigations 3361, under the title ""Active List of Permissible Explosives and Blasting Devices Approved Prior to June 30, 1937.n This list included 196 brand names.Changes in the list that have been authorized to June 30, 1938, placed 7 additional brands of permissible explosives on the active permissible list as a result of tests, changes in brand names, or transfer from the inactive list. Twelve permissible explosives were transferred from the active to the inactive list. The present list contains 191 brand names. The brand names of the permissible explosives placed on the active list are as follows:"

Oct 1, 1938

By A. H. Warner

Sphalerite crystals occur sparingly in minor faults and pockets in a coarsely crystalline dolomite on the Brown-Tipton farm near Greenville in Greene County, Tenn. After several visits by U. S. Bureau of Mines engineers and U.S. Geological Survey geologists, a survey was r: the in the fall of 1944. Upon their recommendations, trenches on the Brown farm under Bureau of Mines supervision. In each case, the bed most favorable for zinc deposition was exposed. In the finished trench bottoms no zinc minerals are visible.

Jan 1, 1950

By Alla D. Mah

The heat of combustion of aluminum carbide (Al, C3 ) , obtained directly by combustion calorimetry , was AH298.15 -1,029.6 ± 1.9 kcal / mole . == The heat of formation of aluminum carbide corresponding to this value was AH298.15 = -53.4 ± 2.0 kcal /mole .

Jan 1, 1964

By Perry G. Cotter

The borides of the transition metals in Groups IV and VI exhibit, in addition to a certain degree of hardness, considerable resistance to heat and oxidation. They have high melting points (1,850°-3,060° C.) and low coefftcients of thermal expansion and can be bonded with other materials and hot-pressed to desired shape (cermets). Suggested uses for the borides include use in rockets and jet engines, as thermocouple protection tubes, as containers for molten metals in die casting, as flame-plated coatings on less refractory compositions to prevent erosion by hot gases, and as control rods and neutron shielding material in nuclear engineering, The Federal Bureau of Mines investigation of zirconium diboride started in 1950 at the Boulder City Nev,, Metallurgy Research Laboratory, Its purpose was to reduce the cost of raw materials for the production of zirconium diboride.

Jan 1, 1961

By R. R. May

A preliminary examination of the Houston strip-coal mine, situated on the Alaska Railroad at milepost 175 (61 rail miles north of Anchorage, Alaska) and a review of all available information resulting from early coal exploration activities in the area resulted in plans to investigate the coal-bearing formations at depth by means of diamond core drilling to indicate the existence of additional reserves of coal in close proximity to railroad transportation, where it would be quickly available to meet rapidly expanding military and civilian fuel requirements. From the date of mobilization of equipment, August 28, 1951, until date of suspension, August 18, 1952, 2,010 feet of diamond drilling was completed. Ten definable coal beds were cut, of which 2 appear to be persistent and minable over an area of approximately 1/2 square mile. Within this area the 2 minable beds contain approximately 5,000,000 tons of coal in place. Of the remaining beds, at least two others may be minable to the eastward near their projected outcrops; however, these and deeper beds (at least in the vicinity of the drill holes) lie beneath a zone of pressurized gas and brackish water. From a practical standpoint, continued development and utilization of the coal in this vicinity will depend on the operators' ingenuity in developing cheap mining methods and on diligent prospecting for strippable coal under the comparatively light glacial cover.

Jan 1, 1957

By L. P. Kleinmann

To control the formation of acid drainage at its source, the Bureau of Mines has investigated the role of iron-oxidizing bacteria in the oxidation of pyrite. In laboratory tests, it was determined that Thio-bacillus ferrooxidans could be controlled in coal refuse using anionic surfactants, with an associated decrease in acid production of about 75 pet. Based on these results, large-scale tests were conducted at an 8-acre active coal refuse area in northern West Virginia and an 11-acre inactive refuse pile in southern West Virginia. Acid production was decreased 60 to 95 pet for 4 to 5 months after application of 55 gal/ acre of 30-pct sodium lauryl sulfate solution. To date, effluent surfactant concentrations have been extremely low. Either a hydroseeder or a road-watering truck can be used to apply the surfactant. Since the surfactant solution must reach the pyritic material to be effective, sites that have been reclaimed are generally not amenable to these procedures. A simple laboratory test is described that provides an estimate of adsorption potential; this can be used to calculate a safe application rate.

Jan 1, 1983

By G. S. Baur, J. W. Montoya, S. R. Wilson

Beryllium occurs in the Honeycomb Hills area in volcanic tuff similar to the more extensive berylliferous tuff occurring 20 miles east at Spor Mountain , Juab County , Utah . Samples from the two areas have been mineralogically examined to ascertain whether they have similar characteristics . The Honeycomb Hills samples showed the presence of beta- Be ( OH ) 2 , as well as an amorphous berylliferous substance , whereas in the Spor Mountain tuff the beryllium- bearing minerals are hydrated bertrandite and berylliferous saponite .

Jan 1, 1964

By Marcia L. Harris

The National Institute for Occupational Safety and Health (NIOSH), as part of its continuing research program for evaluating coal dust explosion hazards, has investigated several areas in which current practices may need to be updated in order to adequately protect mines against coal dust propagated explosions. In the United States, current rock dusting requirements remained largely unchanged since 1969. US Title 30 Code of Federal Regulations Section 75.403 is based on a coal dust particle size survey performed in the 1920s and later was supplemented by full-scale testing of the rock dust ability to inert a coal dust explosion. NIOSH recently conducted a comprehensive survey of US underground coal mines to determine the range of coal particle sizes found in dust samples collected from the mine entries. Due to advancements in technology and modern coal mining techniques, the current coal dust particles in intake airways are significantly finer than those found in the mines in the 1920s. According to past full-scale dust explosion test results, the current rock dusting practices used in today?s mines to inert a coal dust explosion may not be adequate. Other closely related issues such as rock dust testing methods and sampling procedures are discussed.

Jan 1, 2009

By R. F. Abernethy

A modified Unterzaucher method was applied to the direct determination of oxygen in coal. Coal samples were pyrolyzed in a nitrogen atmosphere, and the gaseous oxygen compounds liberated were converted to carbon monoxide by a platinized-carbon catalyst at 9000 C. After passing over heated copper and through a tube containing soda-asbestos and magnesium perchlorate, the purified carbon monoxide was oxidized to carbon dioxide by iodine pentoxide--liberating an equivalent amount of iodine. The iodine was titrated with 0.02 ~ sodium thiosulfate; in a few tests the weight of carbon dioxide produced was determined. Direct oxygen determinations of coal included organic oxygen from the coal substance, plus a small quantity of inorganic oxygen derived principally from carbonate minerals and from combined water of silicates in the mineral matter. The influence of mineral matter on the direct oxygen determination was investigated by testing (1) untreated coal, (2) demineralized coal from which most of the mineral matter except pyrite was removed by treatment with hydrofluoric and hydrochloric acids, and (3) coal samples treated with dilute hydrochloric acid.

Jan 1, 1966

By Timothy A. Clancy

In support of research on forming ceramics from mining and processing wastes, the Bureau of Mines tested various commercial refractories to evaluate their resistance to melts of these wastes. Sixteen refractories of various types were exposed in slag erosion tests to two siliceous waste melts with Si02/CaO ratios of 4.0 and 2.2, The extent and nature of slag attack were then determined for each refractory. The nature of slag attack was investigated through scanning electron micrographs and microprobe elemental distributions. The refractories that performed best in resisting attack by the melts were high-alumina types, and of the refractories tested, the most resistant was a 90-pct-Al203, 10-pct-Cr203 refractory.

Jan 1, 1983

By R. H. Lien

The Bureau of Mines investigated nitrous oxide (N20) stability when used as a solvent for organic removal from metal powder surfaces. Both supercritical and subcritical conditions were studied. This investigation was prompted by the occurrence of a violent reaction when supercritical N20 was being used to deoil a metal powder grinding waste sample that contained 20 to 25 wt pct cutting oil. Tests were conducted to determine the cause of the reaction and to define stability limits. Test data showed that the waste's oil fraction reacted violently with N20 acting as an oxidizer; the metal powder acted as a promoter to reduce the ignition temperature. Although the data were scattered, this temperature appeared to reach a minimum at a certain pressure (dependent on vessel and sample size). The minimum ignition temperature for a 0.64-g sample in a 72-cm3 vessel was 360° C at 200 psig. As the sample size increased, the ignition temperature decreased. For example, when the sample size was increased to 10 g, a reaction occurred at 240° C and 600 psig. Because of the variability of ignition temperature with pressure and sample size, safe operating conditions were not established. Overall, this research showed that extreme caution should be exercised when using N20 in an organic or organic-metal system.

Jan 1, 2011

By C. M. McCulloch

The methane content of virgin bituminous coalbed can now be measured accurately in the field with exploration core samples from vertical boreholes. The gas content of the coal per unit weight can be used either to design a mine ventilation system or to determine if degasification of the coalbed will be necessary before mining, and to determine the gas resources in the coalbed. The equipment necessary to conduct the test costs less than $50. The gas con-tent of the coal in place in the ground is determined by summing the gas lost from coring, gas measured during desorption, and the residual gas in the coal. Upon removal from the borehole, the core sample is placed in an airtight container and des orbed for several weeks until the desorption rate is below 0.05 cm3/g for 5 consecutive days. The gas lost from the core while it was being cored and the residual gas are estimated by a new graphical method. The amount of gas remaining depends upon whether the coal is friable or blocky. Friability appears to relate to the depth of the sample below the surface, fixed carbon percentage, Hardgrove grindability index, and proximity to tectonic disturbance. Friable coals emit nearly 96 pct of the total gas during desorption whereas a blocky coal emits only 60 pct of its total gas. Coalbeds that are ill defined as to their blocky or friable nature must be tested in the laboratory for unambiguous analysis.

Jan 1, 1975

By K. K. Kershner

The purpose of this research by the Federal Bureau of Mines was to investigate the recovery of tin from mine-run ores and low-grade concentrates. Over 95 percent of the total tin in such materials was volatilized to tin chlorides at temperatures ranging from 520° to 565° C. Gaseous mixtures of hydrogen and hydrogen chloride were used for reducing cassiterite to stannous oxide and for converting this compound to tin chlorides. The chlorides were swept from the reaction zone of an oscillating kiln by a rapid flow of reactant gases and collected in a condensing system. Losses of tin that occur in current metallurgical processing were prevented. Approximately the same time of treatment was required for minus 35-mesh mine-run ores and low-grade concentrates. In a continuous process, the circulating gases would require some enrichment.

Jan 1, 1961

By Harry Perry, Mary S. Esfandiary

This is a revision of a directory of coal research organizations throughout the world that was first published in 1961 as Bureau of Mines Information Circular 8008. Because of the wide acceptance of the first edition , a revision which would supply up- to - date information on coal research and which would facilitate communication among organizations of similar interest seemed important . This compilation includes the names and activities of organizations of various types -government , university , private , and industry . The areas of investigation that each organization is engaged in are indicated in broad terms : Analysis and constitution , mining and geology , preparation , briquetting , combustion , high- and low-temperature carbonization , gasification , conversion to solid and liquid fuels , and health and safety . Publications issued by and describing the work of each organization are cited ; almost all of the organizations also publish results of their investigations in the technical press . Selected technical and trade publications that publish information on the science and technology of coal and are not published directly by any of the organizations listed are cited in the pages following the list of organizations in each country . Information that would improve coverage and accuracy of the next revision of the publication will be welcomed by the Bureau of Mines .

Jan 1, 1966

By Franklin D. Cooper

The value of nonfuel mineral raw materials produced in the United States in 1978 was $20 billion. In 1979, total value increased to an estimated $24 billion, up 20% from 1978. Of the principal metallic ores produced in 1979, about half showed increased quantitative output and all showed increased value per ton compared with that of 1978. Most nonmetallic commodities showed increases in quantitative output and in average value per ton. Because of its decreasing share of the world market, the domestic mineral industry's concerns were the increasing costs of capital, labor, and energy; withdrawals of public lands from mining; and the increasing cost of environmental regulations that tended to deter or delay investment in the Nation's capacity for producing essential minerals.

Jan 1, 1980

By S. J. Pearce

The Bureau of Mines has prepared, as circumstances have dictated, a series of Schedules setting forth the minimum requirements that various types of equipment should meet to be considered safe and satisfactory for use in certain hazardous or unhealthful conditions. These Schedules cover a wide variety of devices ranging from explosives to electrically operated mine locomotives. This paper deals with those Bureau of Mines Schedules under which respiratory protective devices are tested and approved, and its purpose is to explain the function and operation of these Schedules. Provisions have been made for testing and approval of the following types of respiratory protective devices: Self-contained breathing apparatus,2/ supplied-air respirators,3/ gas masks,4/ dispersoid respirators,5/ and chemical cartridge respirators.6 These devices are tested at the Central Experiment Station of the Bureau of Mines in Pittsburgh, Pa. Self-contained breathing apparatus is tested by the Safety Branch, and the other types of respirators are tested by the Health Branch.

Jan 1, 1951

By J. C. Meeks, C. L. Klingman

An instrument that is sensitive , portable , safe , and low in cost was developed by the Bureau of Mines for detecting helium leaks by comparing the thermal conductivity and flow rate of the atmosphere around the suspected leak against a reference of helium- free air . A vacuum pump pulls the sample gas through a restriction and over thermistor elements , the combined electrical output of which is affected by thermal conductivity and flow rate of the sample gas . Tests showed that the battery - operated Helium Leak Detector was effective and rugged instrument that could be operated safely in explosive atmospheres . The instrument could also detect , but not identify , other gases such as methane , hydrogen , argon , carbon dioxide , and Freon 12 .

Jan 1, 1964

By Fred N. Kissell

Air recirculation caused by dust scrubbers at coal mine working faces was examined by the Federal Bureau of Mines with regard to the potential hazards caused by a possible buildup of methane gas. A theoretical analysis indicated that there was no apriori way to predict the effect of scrubber recirculation on methane concentration levels. Experiments conducted in a full-scale model of a working face area indicated that methane levels were dependent to a great extent on the location of the scrubber exhaust, but that the scrubber recirculation did not substantially increase the methane concentration above those levels that would have prevailed were the scrubber not in operation. An analysis of two underground scrubber trials showed that the scrubbers had no significant effect on methane levels, and a review of explosions attributed to recirculation showed that these were characterized by a lack of fresh air as well as recirculation. It was concluded that high methane levels are due more to a lack of fresh air than to recirculation.

Jan 1, 1975