Search Documents

By John A. Johnson

[Tests were conducted at the Mount Weather testing adit of the Bureau of Mines4/ on the effectiveness of spraying water along the outside of the drill steel as compared with standard wet-drilling practice. The spray equipment used in the tests was designed primarily for the control, in quarries, of dust from dry drilling with solid type drill steel. EQUIPMENT Spray equipment is made in sizes to fit different drill steel but is alike in design, the only difference being in the diameter of the ring and the number of spray holes. The device is made of cast steel and has a coating of Stellite on the inside edge that comes in contact with the drill steel. It looks like a garden spray, except that the spray holes point in only one direction.]

Jan 1, 1939

By C. E. Coleman, Joseph D. Davis

During some distillation experiments conducted by the Bureau of Mines in cooperation with the Trent Process Corporation it was observed that amalgams of heavy petroleum oils and finely pulverized coal tended to produce a denser coke than that obtainable from the coal when retorted alone . Even anthracite coal when retorted with oil yielded a coke . This led the writers to believe that by mixing a lowrank coal ( sub-bituminous or even lignite ) - with asphaltic oil and retorting it, a coke suitable for domestic fuel could be made . Thus there was contemplated the production of domestic coke and the utilization of a low- grade oil in one operation . - In order to decide on the practicability of this process , it was necessary to know the value of products obtainable by such a method , as compared with those obtained by separate distillation . A laboratory method was therefore devised , and while it was realized that no small - scale testing apparatus for destructive distillation gives results that are directly applicable to commercial - scale operations , by keeping distillation conditions uniform for comparative tests , results were obtained valuable for purposes of comparison . The plan was to distill mixtures of coal and oil in a laboratory retort , and then distill the constituents separately under the same conditions . The comparative quantities of products yielded were thus directly obtained , and their quality was determined by analysis . The following are the main points investigated : ( 1 ) Quantity and quality of coke ; ( 2 ) Quantity of oils boiling below 221 °C . ( gasoline stock) and oils boiling at 221 to 300° C . ( kerosene stock) ; and ( 3) Quantity and quality of gases .

Jan 1, 1922

By C. A. Herbert

The mine of the Alpha Portland Cement ..Co., Iroaton, Ohio, ..working in. a. bed of limestone 96 feet thick at a depth of approximately 510 feet below the surface, has established a won¬ derful safety record, having operated 6 years—frcra September 21, 1926,. to September 21, 1932 - without a lost-time accident. This mine, with 61 to 86 employees (average 68) and daily output of 1,000 to 1,200 tons of limestone, operated 1,041 days during the 6-year period, or the equivalent of 578,894 man-hours of exposure. ...... ... . Immediately above the limestone is a 20-foot .bed of hard..sandstone.. At present about 10 feet of limestone is left up as. a roof and.about. 42 feet is being extracted. Of the lower portion of the bed it is believed that about. 25 feet. ..immediately below . the .present workings is suitable for cement and will be extracted later. The mine workings are reached by two rectangular concrete shafts, one a 2-compartment hoisting shaft and the other a 2-compartment air and escape shaft- In the latter shaft one compartment is used as an airway and the other, as a cage compartment fo.r a man and material cage. .. . - . The tipples at both the air shaft: and. hoisting shaft are-of steel. The.ground landings at both shafts are fenced in with hand-operated gates in front of the cage compartments.- The two shafts and the crushing plant, which .is.a part of the hoisting shaft-tipple structure, are adjacent to the mill buildings. The rock is hoisted on self-dumping cages in 4 ton capacity, end-gate, steel cars. An electric hoist with automatic overwind device is used at both the main shaft and air shaft. The controls for the main hoist are in the tipple where the engineman is stationed and from which point he has an unobstructed view of both the ground, landing and the cage coming into the dump.

Jan 1, 1933

By Paul M. Tyler

The alkali metals , sodium and potassium , and more particularly sodium , occur abundantly in chemical combination with other elements . The elements themselves are available in metallic form but are so active chemically that they oxidize rapidly in contact merely with the air . Potassium will even catch fire spontaneously in air , and both the metals will decompose water with explosive violence . Inasmuch as they are almost as soft as wax they are not suitable for the structural or other mechanical uses characteristic of ordinary metals , and consequently the uses of these elements even in the metallic condition are based upon chemical rather than physical qualities . Sodium metal is used largely as a commercial reducing agent , but potassium metal is rarely found outside of chemical laboratories . Numerous salts and other compounds of these elements enter largely into world trade and are commercially very important , but none of these compounds except sodium peroxide and sodium cyanide are made economically from the metals . Sodium is generally considered as rather an uncommon metal , but in point of annual tonnage produced it is far more important than mercury , magnesium , molybdenum , bismuth, cadmium, cobalt , gold , silver , or the various rarer metals .

Apr 1, 1932

By L. C. IlsLey

The work of the electrical section of the Bureau of Mines may be considered to have had its beginning in April , 1909 , when H. H. Clark was , appointed electrical engineer in the U. S. Geological Survey. The first manuscript prepared by members of this section was Miners Circular 5, which was issued in October , 1911. During each succeeding year additional papers have been published dealing with questions relating to electrical safety. Since 1916 the electrical section has also conducted laboratory investigations on flame safety lamps and gas- detecting devices and has published reports relating thereto . The following selected list of publications covering safety studies and activities of the electrical section has been prepared for the convenience of those who wish to keep themselves advised concerning electrical safety matters . The list includes only such publications as are applicable to present-day prac tices .

Jul 1, 1930

By S. H. Katz

In the Bureau of Mines investigations of respiratory apparatus, a laboratory study of dust respirators has been conducted, and the results will be published in detail as a technical paper. Many industrial dust respirators, and many fabrics and filtering materials were tested. The principal results of these tests, and the conclusions drawn from them, are presented below. Reference to the patent literature discloses numerous types of dust respirators, mostly based on the filter principle. The present study included only representative filter-type respirators, purchased on the market.

Jan 1, 1926

By Edward D. Thimons

Because of the high number of accidental methane gas ignitions in metal and nonmetal mines, the Bureau of Mines searched for a simple guideline that would allow mine personnel to evaluate the methane hazard in a given mine. Air samples were collected by the Bureau in 53 metal and nonmetal mines and analyzed for trace evidence of methane gas. Samples were collected in the returns and at the working faces. Those mines classified as gassy by the Mine Safety and Health Administration had a significantly higher average methane concentration than those classified as nongassy. Of the 9 gassy mines sampled, 7 had methane concentrations above 100 ppm, whereas only 1 of the 44 nongassy mines had a concentration above 100 ppm. The 100-ppm concentration may be used as a simple and convenient guideline for forecasting the methane hazard in a mine, whether or not the mine is classified as gassy. There was no consistent correlation between commodity mined and methane concentration, nor was there a correlation between mine depth and methane concentration. Neither of these factors can be considered a guideline for predicting methane hazards.

Jan 1, 1979

By William H. Schiffbauer, Ph. D. Mowrey

Proximity warning devices can improve workplace safety by alerting workers when they are in a hazardous area near moving equipment. Industrial work sites often present extreme challenges to safety-based proximity warning devices. Many commercially available types of proximity warning sensors and systems can be rendered useless when covered with mud, ice, snow, ore, rock, and other material. The list includes radar, ultrasonic, capacitive, and visual types of sensors and systems. Addressing these shortcomings, NIOSH personnel have developed a patented active proximity warning system called HASARD (Hazardous Area Signaling and Ranging Device) which employs lowfrequency, low-power magnetic fields which are quite impervious to severe environmental conditions. A shapeable wire loop antenna which provides the marker of dangerous work areas, has been mounted on a continuous mining machine and was mounted inside 1.3-cm thick angle iron. This loop antenna was exposed to more than six months of active underground coal production, which included being covered by and scraped over with tons of rock, sprayed by a continuous stream of water, and immersed in thick mud. After six months the loop antenna showed signs of wear, but was still capable of performing its intended function. The HASARD system is now being applied to other industrial applications and is showing much promise, especially in harsh environments. This paper details the system, describes the tests that have been done, and mentions other areas where it can benefit the safety of industrial workers.

By Martin S. Oudenhoven

This Bureau of Mines report presents the results of a microseismic study conducted in the Climax block cave mine at Climax, Colo. Rock noises created by caving were monitored and their sources located during a 3-month period. A planar array of seven accelerometers, located above the block of ore being caved, detected the rock noise. A computer was used to calculate the location of the microseismic activity, using a traveltime difference method. The accuracy of these locations was estimated to be ±20 feet. An analysis of the data taken during the recording period showed a concentration of microseismic events located in the wall of the cave panel. This concentration of events was found to occur in a "high-silica" geologic forma-tion that cut across the caving panel approximately 200 feet behind the undercut.

Jan 1, 1973

By W. A. Haley

This is the second of a series of publications that describes the progress of mechanical longwall coal mining in the United States in which a German coal planer was employed.3/ Details of the equipment, a description of its operation, and the results obtained in mining the experimental panel were published in the preceding report. Experimental mining with the planer in the first panel showed an improvement in performance over conventional mining methods at the coal company's Stotesbury 11 mine. The work, which was begun on an experimental basis, soon proved successful, and the coal company purchased the equipment for continued use. Two panels, adjacent to the first, were developed and mined with the planer. Each of these panels was shorter than the preceding one because water seepage from a surface creek limited development. On completion of mining in the third panel, the planer equipment was moved by the cooperating company to a nearby mine operated in the same coal bed where a large area of coal suitable for planer mining is available.

Jan 1, 1954

By Richard J. Mainiero

Traditional techniques for the experimental determination of toxic fumes produced by the detonation of high explosives are not applicable to blasting agents. To detonate properly, blasting agents require confinement, a significant booster, charge diameters of 3 inches (7.5 cm) or greater, and charge lengths greater than two-times the charge diameter. Without these conditions, blasting agents will not detonate at full order, leading to a misrepresentation of the gaseous products. A facility for detonating large, confined charges in a controlled volume has been constructed at the Pittsburgh Research Center’s Experimental Mine. The facility consists of a portion of mine entry (once used for full-scale mine explosion research and demonstrations) enclosed between two explosion proof bulkheads. Total volume of the chamber is 9,666 ft (274 m). The chamber is equipped with an air circulating system and is3 3vented using the mine's airflow. Up to 10-pound (4.5-kg) charges can be detonated in the chamber using a variety of confinements. For a typical test, the blasting agent is confined in a 4-inch (10-cm) schedule 80 steel pipe and initiated by a 3-inch (7.5-cm) diameter, 1-inch (2.5-cm) thick Pentolite booster. This combination of confinement and initiation yields a detonation velocity of about 4,000 m/sec for ANFO. This velocity is in line with that measured for blasting in the field. Twenty four 2-inch thick steel plates are suspended around the pipe bomb to stop shrapnel that would otherwise seriously damage the chamber. Following detonation of an explosive in the chamber, a circulating fan is run for about 10 minutes to uniformly mix the chamber atmosphere. Fumes samples are taken out of the chamber through 1/4-inch (0.6-cm) Teflon or polyethylene2tubes for analysis. The fumes are analyzed using bubblers or Vacutainers to collect samples for analysis by the analytical chemistry lab. The technique described here has been employed to determine the fumes produced by the detonation of a variety of ANFO formulations and commercial explosives. This technique may be developed as a standard test to measure fumes produced by blasting agents or may be used to provide data with which to develop a computer model that will reliably predict the expected fumes production based on chemical composition.

By Hugo E. Camargo

In an effort to reduce Noise Induced Hearing Loss (NIHL) in the mining industry, the National Institute for Occupational Safety and Health (NIOSH) is conducting research to develop noise controls for mining equipment whose operators exceed the Permissible Exposure Level (PEL). The process involves three steps: 1) Noise source identification (NSI), 2) development of noise controls, and 3) evaluation of the developed noise controls. For the first and third steps, microphone phased array measurements are typically conducted and data are processed using the conventional beamforming (CB) algorithm. However, due to the size and complexity of the machines, this task is not straight forward. Furthermore, because of the low frequency range of interest, i.e., 200 Hz to 1000 Hz, results obtained using CB may show poor resolution issues which result in inaccuracy in the noise source location. To overcome this resolution issue, two alternative approaches are explored in this paper, namely the CLEAN-SC algorithm and a variarion of an adaptive beamforming algorithm known as Robust Capon Beamformer (RCB). These algorithms were used along with the CB algorithm to process data collected from a horizontal Vibrating Screen (VS) machine used in coal preparation plants. Results with the array in the overhead position showed that despite the use of a large array, i.e., 3.5-meter diameter, the acoustic maps obtained using CB showed "hot spots" that covered various components, i.e., the screen deck, the side walls, the I-beam, the eccentric mechanisms, and the electric motor. Thus, it was not possible to identify which component was the dominant contributor to the sound radiated by the machine. The acoustic maps obtained using the RCB algorithm showed smaller "hot" spots that in general covered only one or two components. Nevertheless, the most dramatic reduction in "hot" spot size was obtained using the CLEAN-SC algorithm. This algorithm yielded acoustic maps with small and well localized "hot" spots that pinpointed dominant noise sources. However, because the CLEAN-SC algorithm yields small and localized "hot" spots, extra care needs to be used when aligning the acoustic maps with the actual pictures of the machine. In conclusion, use of the RCB and the CLEAN-SC algorithms in the low frequency range of interest helped pinpoint dominant noise sources which otherwise would be very hard to identify.

Jan 1, 2009

By Charles A. Kumke

In June 1942 , ' the Bureau of Mines selected the Zonia copper mine , near Kirkland , Yavapai County , Arizona , as a property meriting investigation in connection with its search for supplies of strategic minerals for use in the war . The following month , representatives of the War Production . Board conferred with Bureau officials and requested that the property be explored with the object of determining the tonnage and grade of ore that could be brought into production quickly and mined cheaply by open-pit methods . The work wa's designed to verify information submitted by the owners in support of an application for a Government loan. It was essential that the investigations be completed promptly , so that operations might be planned and copper produced for war needs . The investigations called for surface trenching , diamond drilling , and check sampling of underground workings . Unable to purchase equipment for trenching without considerable delay , the Bureau saved time by borrowing most of the necessary items from the Golden Queen mine of the Gold Fields Development Co. at Mohave , Calif. This company , whose engineers had sampled some of the old trenches , had a tentative agreement with the owners to operate and manage the Zonia mine in event the loan was granted . Additional equipment was borrowed from two Governmental agencies . The exploratory work , completed in 16 weeks , was carried on 7 days a week .

Mar 1, 1947

By Robert T. Beckman

The results of a preliminary investigation of compressive strength versus length-diameter (L/D) ratios of potash specimens and the statistical treatment of the data are summarized in this report. The purpose of the study was to evaluate a laboratory method for obtaining estimates of the strength of potash pillars during robbing operations. The specific objectives of this preliminary investigation were to test the method and the reliability (confidence limits) of the data, and to determine the number of additional specimens necessary for given confidence limits. The specimens were taken from three sites at two mines in New Mexico. The statistical analyses included the determination of the confidence limits for the data and the number of additional specimens necessary to obtain confidence limits of ±500 and 100 psi. The testing method was found acceptable, and estimates of the comprehensive strength, within 1500 psi, could be obtained by testing about 110 additional specimens from the three sites. The compressive strength of the specimens tested fits an empirical equation of the type

Dec 1, 1963

By R. M. Santmyers

This paper represents one of a series of digests of foreign mining legislation that is being prepared in advance of a general report relative to the rights of American citizens to explore for minerals and to own and operate mines in various foreign countries . This interpretation of the mining legislation of Tunisia was prepared from a copy ( in French ) of the Mining Decree of Tunisia promulgated December 29 , 1913 , by the Resident General of France in Tunisia and effective January 1 , 1914. It is released subject to correction and amplification , if necessary , by the proper American diplomatic and consular officers , to whom it will be referred through the courtesy of the Department of State .

Mar 1, 1933

By E. B. Swanson

Atlantic seaboard refining and marketing companies , dependent largely upon other producing and refining areas for the crude and refined petroleum needed to meet the demand for petroleum products within the Atlantic Coast States , reported an increase in 1929 receipts of 2,542,000 barrels of crude petroleum and 13,479,000 barrels of gasoline over the quantities received during the preceding year . The relatively large expansion in gasoline receipts undoubtedly resulted from the unexpected increase in gasoline consumption which characterized the petroleum industry during 1929. Gasoline receipts from California increased 6,354,000 barrels and shipments from foreign countries were 5,381,000 barrels in excess of the 1928 figures , while receipts from Gulf Coast ports , the major source of outside supply, declined 811,000 barrels . Shipments of domestic crude oil by tanker from Gulf Coast ports during 1929 continued the average annual increase of approximately 7,000,000 barrels which has been recorded during the five years of this annual survey . These shipments have increased from 72,556,000 barrels during 1925 to 99,828,000 barrels during 1929. Shioments of Mid- Continent crude by pipe- line to Atlantic Coast refineries have , on the other hand , dropped from 11,903,000 barrels in 1925 to 1,409,000 barrels during 1929. Receipts of foreign crude oil declined 1,461,000 barrels from the preceding year . : Gasoline demand within the Atlantic Coast area reached a total of 123,345,000 barrels , an increase of 15.7 per cent over 1928. Gasoline production increased 4,157,000 barrels , while tanker receipts were nearly 11,000,000 barrels larger than in 1928. Indicated shioments from Appalachian refineries were somewhat larger than in the preceding year . Gasoline production showed an average of 33.5 per cent of the crude throughout , as compared with 31.5 per cent in 1928 and 32.7 per cent in 1927. Cracking operations accounted for 44.6 per cent of the gasoline produced , as compared with 40.6 per cent in 1928 and 35.3 per cent in 1927. Gas oil and fuel oil production averaged 52.8 per cent of the crude throughput , as compared with 55.1 per cent in 1928 and 49.5 per cent in 1927 , the decline reflecting the smaller quantities of foreign crude refined during the year .

Nov 1, 1930

By B. J. Scheiner

As part of the goal to maximize minerals and metals recovery from primary domestic resources, design factors associated with minimizing current leakage in bipolar cell configurations were studied by the Bureau of Mines as a means of improving the efficiency of bipolar e1ectrooxidation cells. Initial studies that were conducted in a small bipolar cell operating at 140 to 145 volts and 15.4 amp indicated how design factors could be employed to minimize cur-rent leakage around adjacent electrodes during cell operation. Based on these results, a 40-electrode, 108-kva prototype of an industrial-sized cell was constructed and tested for extracting metal values from offgrade molybdenite concentrates. The feasibility of recovering molybdenum and rhenium from the oxidized pulp also was determined. Feed to the process sequence consisted of flotation concentrates containing 16 to 35 pet Mo as molybdenite and 6 to 15 pct Cu. E1ectrooxidation in the prototype cell resulted in 84 to 97 pct Mo and Re extraction with a corresponding energy consumption of 9 to 13 kwhr/1b Mo extracted.

Jan 1, 1979

The method of using large-diameter augers to recover coal was introduced to the mining industry about the end of World War II, and production of bituminous coal with augers has increased steadily to an estimated 7 million tons, or approximately 1.4 percent of the total mined in 1956. Although auger mining has proved to be a reliable and economical method of mining coal, a number of unfortunate fatal accidents have been experienced; consequently the need for these recommended safety standards is indicated for this comparatively new method of coal mining. As mining methods and equipment change from time to time and new hazards are introduced, these standards will be revised; therefore, questions or suggestions from the coal-mining industry will be welcomed and carefully considered.

Jan 1, 1958

By Gerald L. Finfinger

The Bureau of Mines conducted an experimental degasification project in Island Creek Coal Co.'s Virginia Pocahontas No. S mine. Methane from the overlying Pocahontas No. 4 coalbed was entering mine workings in the Pocahontas No. 3 coalbed through fractures in the roof rock. Small-diameter (l-S/B-inch) holes were drilled into the overlying coalbed to reduce the gas pressure and intercept methane flows, which were piped to the surface through an underground 6-inch-diam steel pipeline. The total methane flow rate from the vertical holes averaged 150,000 ft3/day for the first month. Methane flows into the mine were reduced by 47 pet, thereby demonstrating the effectiveness of this form of degasification in reducing ventilation requirements and providing a safer working environment.

Jan 1, 1979

By D. Harrington, F. E. Cash

For a number of years the efforts of the coal -mining industry , as well as of the Bureau of Mines , have been directed largely towards the limitation and prevention of explosions in coal mines . The origin of most explosions is ignition of methane or marsh gas , but the extent and violence of these explosions depend chiefly on the combustible dust present . The Bureau of Mines has conducted a large number of tests on the use of incombustible materials in limiting or preventing widespread explosions . The result of these tests , published in Bulletins 167 and 268 and Technical Paper 386 , proves that incombustible dust can be so applied and maintained in coal mines that the ignition of the mixture of incombustible and combustible dusts , or the propagation of flame by the dust mixture , is impossible ; on the other hand , experience and experiment indicate that watering methods are not reliable as a preventive of general or widespread coal-mine explosions . This report describes the use of " mudite , " a mixture of water and finely divided incombustible soil or dirt applied in some coal mines as a means of attempting to limit or prevent widespread explosions .

Jan 1, 1929