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By A. C. Smith

The U.S. Bureau of Mines developed an experimental method to evaluate the relative effectiveness of water additives on the extinguishment of coal fires. The experiments were conducted in the fire zone of the multiple-entry section of the Bureau's Bruceton Experimental Mine. Four-hundred-pound Pittsburgh Seam coalbeds were ignited and allowed to burn until well-developed fires were achieved. Extinguishing agent-water solutions were then applied to the fires, and the quantity required to extinguish the fires was compared with the quantity of water alone required to extinguish similar fires. A 20% diammonium phosphate-water solution required an average of 5.8 gal to extinguish the coal fires, while two commercially available additive-water solutions required an average of 8.1 and 8.0 gal, respectively. The average amount of water required to extinguish the fires was 7.4 gal. An analysis of covariance, using the thermal energy of the coalbed to quantify the fire at the time of extinguishment, showed that the diammonium phosphate-water solution was slightly more effective at extinguishing these coal fires than water alone, and the two commercially available additive-water solutions were statistically equivalent to water alone.

Jan 1, 2010

By Deno M. Pappas

The purpose of this Bureau of Mines study of U.S. roof and rib (roof- rib) accident statistics and related accident costs is to define current accident trends (1980-84) associated with fatal and nonfatal roof-rib fall accidents. Data were retrieved from a data base containing all recorded U.S. mining accidents, then sorted and normalized utilizing a computer software program. The statistics indicate that roof-rib accidents have significantly declined in the 5-yr study period. Moreover, they indicate that there have been increases and/or patterns of roof-rib accidents associated with specific mine characteristics, such as seam height, mine size, geographic location, and seasonal variations. Also, roof-rib injury characteristics produced pattern changes involving worker activity, lost workdays, types of injury, and severity of injury. A conservative estimate indicates that there has been a 30% adjusted increase in the cost of a roof-rib accident over the 5-yr study period.

Jan 1, 1987

By D. Harrington

The mining industry of the United States has for many years possessed the dubious aistinction of having the poorest accident rate of all of the major lines of industrial endeavor in this country, and until recently there ras little or nothing to show that any material improvement might be expected. However, there are now numerous trends indicating that the corner has ceen turned at last, and it is strongly hoped that the mining industry is likely to follow the railroads, the cement and other industries in operating with occurrence of only a reasonable amount of loss of life and limb through accidents. The complete accident figures for metal and nonmetallic mineral mining for 1931 are not yet available, but fragmentary data shor that 1831 vill un- questionably have very low accident rates, probably the lowest in the history of our metal mines. One underground metal mine has produced over 14,000,000 tons of copper ore rithout a fatality; another metal mining company with an electric slovel operation has handled upwards of 75,000,000 tons of material, copper ore and waste, without the occurrence of a fatality; an iron-ore compan, which orns six mines (three underground, three open pit), has operated every one for a year or more without a lost-time accident with a con- siderable number of employees and a large production; and alot.er iron-ore producer with 30 mines and about 3,000 employees as an average of nearly 10 months of operation in 1931 without a lost-time accident. umerous other wonderful safety records of metal mines in 1931 indicate unmistaimbly tat the record of the noncoal mining industry of the United States as a role in 1931 will undoubtedly be found to be excellent. According to the latest relatively complete figures (those of 1930) available for the coal industry, fewer than 650,000 persons are employed in and around the coal mines of the United States, the figures indicating at a little over 493,000 people are engaged in bituminous mining and a little under 151,CCO in anthracite mining. Bureau of Mines complete figures suc that 2,053 persons were killed and 103,821 non-fatally injured in our coal

Dec 1, 1932

By J. H. Holden, G. R. Strimbeck, L. F. Willmott, W. R. Huff

A pilot - scale fluidized feeder was developed for continuously feeding up to 1 ton of pulverized coal per hour to a pressure gasifier . Fluidization in the 3 - foot - diameter by 34-1 / 2 - foot - high feeder is effected by two streams of inert gas , a technique called zone fluidization . A stream of inert gas through a drilled plate in the base of a central column near the bottom of the feeder fluidizes the coal . Another stream through a drilled plate in the annulus between the central column and feeder wall provides a source of semifluidized coal for the central column . Fluidized coal from the central column discharges through an extraction funnel and discharge line . Zone fluidization provided good fluidization with moderate requirement for fluidizing gas . Instruments were developed for metering and recording the flow rate of fluidized coal . A system was developed for storing , and weighing pulverized coal , and then delivering it in fluidized form at about 1 to 8 tons per hour .

Jan 1, 1964

By J. F. McIlwain

As part of its goal to minimize the requirements for critical materials, the Federal Bureau of Mines has investigated the consolidation of an iron-base superalloy (20 pct Cr, 5 pct each Ni and Mn, 1 pct each C, W, Mo, and Cb, and the balance Fe) and its modifications by powder metallurgy (P/M) techniques. Vacuum-atomized, prealloyed powder was used. Consolidation was by sintering of cold-pressed alloy powder, or by forging plus rolling or extrusion of canned powder. Several commercial lubricants were evaluated in the pressing operation. At 50-tsi compacting pressure with up to 3 wt-pct lubricant, green strengths did not exceed 1,000 psi. Powder sintered just below the solidus temperature attained a tensile strength of 69,000 psi and 4 pct elongation. Liquid-phase sintering produced higher densities, lower tensile strengths, and nil ductility. Canned powder was forged and rolled at 1,200° C, yielding a 100-hr rup¬ture strength of 9,800 psi at 815° C and a room-temperature tensile strength of >130,000 psi at 6 pct elongation. Heat treatment of modified P/M iron-base alloy containing 0.63 pct C resulted in a 100-hr rupture strength of 17,000 psi. Oxidation resistance at 805° to 815° C of the forged and rolled P/M iron-base alloy was similar to that of the cast iron-base alloy and supe¬rior to conventional stainless steels.

Jan 1, 1981

By Oliver Bowles

This paper is the fourth of the current series issued by the Bureau of Mines on lime- plant problems . It is hoped that the information presented in these reports will develop sufficient interest among lime- plant operators to prompt them to discuss with the Bureau their own experiences , for it is believed by such an interchange of ideas conclusions will be reached that will be of practical benefit to the entire industry . Much valuable information has been obtained from replies to the papers already issued , but a more general response is greatly desired . It is hoped that many operators will contribute additions to the information on transportation systems now at hand by answering the questions on the final page .

Mar 1, 1923

By Charles Vaught, Richard S. Fowkes, Ronald S. Conti, Barbara Fotta, William J. Wiehagen

The purpose of this study was to determine mine workers' state of fire-fighting preparedness and the technology being used to detect and respond to underground coal mine fires. To investigate this problem, 214 underground coal miners were interviewed by U.S. Bureau of Mines researchers. Frequency distributions of workers ' responses are presented in this report, along with segments of narrative accounts, to profile miners' fire-fighting capabilities. The data indicated that much variability exists from mine to mine and that there are several important changes operators may undertake in order to make miners better prepared to deal with fire underground: select appropriate sensors, establish and test a warning and communication protocol, construct a system capable of delivering hundreds of gallons of water per minute for sustained periods, institute formal fire preparedness audits, develop case studies of events that occur at an operation to use as teaching and assessment tools, and provide structured practice that can be incorporated into fire drills.

Jan 1, 1995

By Lung Cheng

The Bureau of Mines conducted laboratory tests to investigate the ease of frictional ingition with frozen (nonrotating) conical bits cutting into sandstone. The number of strikes with a new bit to obtain ignition of a combustible methane-air environment was measured. Tests were made with bits tipped with both tungsten carbide and steel at several bit attack angles (angle between bit axis and sandstone surface) and initial tip angles (included angle at the tip of the new bit). Carbide-tipped bits required more strikes for ingition than steel-tipped bits, by a factor of 7 to 10. With a carbide-tipped bit, the number of strikes for ingition increased by a factor of about 3 if the bit attack angle increased by 10° or if the initial tip angle decreased by 10°. During use, abrasive wear of the frozen bit caused a flat surface to form at the tip of the bit, thereby decreasing the tip angle. As the attack angle increased, however, the new bit involved a smaller wear-flat area whereby, abrasive wear was decreased.

Jan 1, 1987

By Eugene Frey

"INTRODUCTION The Blue Bell fluorite deposits were examined in August and November 1944 by an engineer 3/ of the Bureau of Mines, and an underground project was set up. The Bureau of Mines began development of fluorite here February 10, 1945, and completed its survey on June 21, 1946.ACKNOWLEDGMENTSIn its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepared the final report. The Metallurgical Branch, C. C. Ralston, chief, analyzes samples and perform beneficiaticn tests. The exploratory project was under the direction of Paul T. Allsman, chief, Salt Lake City Division, Mining Branch. Acknow¬ledgment is due R. Thurston of the Federal Geological Survey for mapping the topography of the area, and to F. H. Gunnell and W. A. Young of the divisional office for detailed mapping of the surface and underground development and interpretation of the results.The chemical analyses included in this report was performed under the direction of H. E. Peterson, analytical chemist; the petrographic studies on the ore were written by LaMar Evans, petrographer; and the beneficiaticn section was written by C. H. Schack, metallurgist, under the direction of S. R. Zimmerley, chief, Salt Lake City Division, Metallurgical Branch."

Jul 1, 1947

By Andrew Allan

[Research conducted by the Bureau of Mines hrinq the last 5 years on the uce of machines for 7!naer:rolmrl ?.eve loym~nt in pi.t,c hlng anthracite beds l~a~ provide? data ?howin? that ?:;panrt of thc roof an9 str?eg of thes? oTen - jnqs requires almst half of' the PRS? workin? time. The possibilitie~ of i!rinz a mvable,. te1.ee*co@. c tpr? 3f ?tee1 ~h-!.oltl at the face in~tetcrl of conventional wood a*ti~yorts w?r? si:~q~eteil by engineers engaqad on the~ work If ~uch a shi~l8 COLI.~,~. be ~sve~.~yad, it tnillil man that face workera w~uld be provi8ed with mulrnu.m prot?ct+on from falls of' roof and ribs mi! the en- tire ehift could he I~W? Lo ~lro,J.~:ce cocl. Fermanent tim3er coald be p'l.acnA behind the shielR independently of the 'face work as the face advanced.]

Jan 1, 1953

This summary of State laws on explosives was compiled primarily to ascertain what subjects relating to their control have been acted upon by each State legislature and, in general, how they have been treated. It does not include any legislation passed after 1942, or any proclamations, regulations, or administrative orders. It does not purport or attempt to be authoritative. If any problem arises involving interpretation of the statutes of any particular State, the original source must be consulted for the exact words used by the legislature. This summary, however, will be useful in determining whether relevant statutes exist, and in locating them quickly with a minimum of effort. It will be of value also in comparing statutes in one State with similar statutes in other States to determine what construction has been placed upon them by the courts of these jurisdictions or to contrast the varying provisions of many States upon a similar subject. To make these comparisons easier, the statutory provisions for each State have been grouped under several major topics in outline form. Although this sometimes has resulted in disruption of the continuity of individual acts, the increased general clarity and availability of comparable sections have more than justified the procedure followed.

Jan 1, 1943

By Charles Vaught

The purpose of this study was to determine mine workers' state of fie-fighting preparedness and the technology being used to detect and respond to underground coal mine fires. To investigate this problem, 214 underground coal miners were interviewed by U.S. Bureau of Mines researchers. Frequency distributions of workers' responses are presented in this report, along with segments of narrative accounts, to profile miners' fire-fighting capabilities. The data indicated that much variability exists from mine to mine and that there are several important changes operators may undertake in order to make miners better prepared to deal with fire underground: select appropriate sensors, establish and test a warning and communication protocol, construct a system capable of delivering hundreds of gallons of water per minute for sustained periods, institute formal fire preparedness audits, develop case studies of events that occur at an operation to use as teaching and assessment tools, and provide structured practice that can be incorporated into fire drills.

Jan 1, 2010

By F. D. Everett

Thermoelectric and metal alloying applications have changed the status of tellurium from oversupply to under supply . In a search for new sources of this element in Arizona , Colorado , New Mexico , Utah , and neighboring states , the Bureau of Mines analyzed more than 200 samples and obtained the results of tellurium determinations by private companies on more than 500 samples from a wide variety of mineral - bearing deposits . The About 40 minerals containing tellurium have been reported , mainly tellu- rides of gold , silver , bismuth , mercury , lead , copper , iron , and nickel . minerals usually occur in small quantities and identification in ores is extremely difficult . Samples containing more than 0.1 percent tellurium were taken from the Hilltop and Memphis properties in Dona Ana County , N. Mex . , and the Silver King property in White Pine County , Nev . , where development was chiefly for base metals . The Lone Pine mine in Catron County , N. Mex . , and the Bambolla mine near Moctezuma , Sonora , Mexico are potential sources of native tellurium occurring in small but high- grade pods . Much of the production of tellurium has come as a byproduct of electro- lytic refining of copper and lead- zinc ores in Arizona , Colorado , New Mexico , and Utah . Base -metal ore deposits will continue to be the most important pri- mary source of tellurium , although the concentration in ores is nearly always less than 10 parts per million . Any significant increase in output of tellu- rium probably will be related to production and improved efficiency in smelt- ing and refining base - metal ores .

Jan 1, 1964

By Thomas M. Barczak

This U.S. Bureau of Mines (USBM) report evaluates the load supporting characteristics of grout columns used as point supports for mine subsidence abatement. The cone-shaped columns were constructed with sodium silicate and cementitious grout in both wet and dry environments. The scope of work included the testing of seven full-scale grout columns in the USBM's Mine Roof Simulator from which the load-deformation and failure characteristics were determined. The performances of grout columns are analyzed with respect to (1) the amount of roof contact established during column construction, (2) shape effects produced by the truncated cone geometry, (3) size effects in reference to grout strength and full-scale column capacity, (4) the effect of wet environments on grout strength, (5) the effect of the sodium silicate on the grout strength and full-scale column behavior, and (6) the stiffness of the grout column. Limited tests were also conducted on cylindrical columns constructed in fabric bags. Recommendations for point support construction using sodium silicate technology and the need for additional research to develop improved containment devices for column construction are addressed in the report.

Jan 1, 2010

By H. Winkelmann

The author, who himself has worked inn the field with various types of torsion balances, expresses in the article his experience with the recently marketed Haff-Torsion-Balance. The advantages of practical work with Haff?s s torsion balance as compared with other types are mentioned. In spite of low weight and corresponding small dimensions (Model M = 23.5 kg., Model Al = 11.5 kg.) the sensitiveness is not less than that in the largest instruments. It is at 1.10-9, which is proved by calculations. A comparison with the corresponding values of other types of torsion balances (Eötvös, Askania, Gepege) is given. The mechanical features of the instrument are briefly described, and the balance is illustrated by a, cross section of it. -- W. Ayvazoglou. DETERMINATION OF THE ELEMENTS OF THE MAGNETIC AND GRAVITATIONAL FIELDS INDUCED BY AN INFINITELY LONG HOMOGENEOUS CYLINDER By G. A. Gamburzeff Gerlands Beiträge zur Geophysik, Band 19, Heft 2/3 Leipzig, 1928, pp. 210-230. The present work is a. contribution to the quastion of the reason for the magnetic and gravitational anomalies in the government of Kursk (Russia).

Jan 1, 1929

By Oliver Bowles

Limestone is the most widely used of all racks and is essential to a great many industries, including tae building trades, highway construction, metallurgy, agriculture, end many chemical and manufacturing enterprises. It occurs in some form in every State and is produced in thousands of quarries. Production in 1930 exceeded 134,000,000 tons. It has more numerous and more diversified uses than any other rock. This paper is designed to furnish general information on the various branches of limestone quarrying and their economic importance. Brief reference is made to dimension stone, and a more complete discussion follows of the uses, requisite qualities, quarry methods, grid processes of preparation of crushed and broken limestone. Footnote references serve to guide the reader to more detailed information.

Jan 1, 1933

By Deborah A. Kramer

This Bureau of Mines report presents a cost estimate of the Bayer process, which is used for virtually all cell-grade alumina production. The report will serve as a reference point to determine the economic merits of processes that have evolved from Bureau of Mines investigations on technology for producing alumina from domestic nonbauxitic raw materials. The Bayer process involves dissolving the alumina present in bauxite in a caustic solution at high temperature and pressure. After the un- dissolved impurities are removed, the solution is seeded to produce an alumina trihydrate precipitate. This precipitate is filtered, washed, and calcined to produce the cell-grade alumina product. This cost estimate is for a plant producing 1 million tons of alumina per year. The estimated operating cost is approximately $250 per ton of alumina.

Jan 1, 1983

By Robert W. Ageton

The Bureau of Mines investigated the in situ vertical component of the rock stress in the rib of the haulage drift on the 6100-level of the Star mine, Burke, Idaho, using the flatjack and borehole deformation methods. The estimate of the vertical component of stress about 2 feet into the rib at a station along the haulage drift on the 6100-level of the Star mine by the flatjack method is approximately 5,875 psi, whereas the borehole deformation procedure at this station yielded a value of 5,500 psi for the same depth into the rib. The test zone is approximately 5,625 feet below the surface.No attempt was made to extrapolate stress estimates beyond the depth of the flatjack installation.

Jan 1, 1967

By James W. Ballard

The facts are generally accepted that an atmosphere containing large quantities of any dust is objectionable to breathe and that some dusts are more dangerous than others. Therefore, knowledge of the com-position of dusts is important in evaluating the hazard entailed on exposure. At present, free silica, of which quartz is the most abundant form, is considered one of the most significant dusts, from the standpoint of pneumoconiosis, and one State5/ has established permissible limits of air dustiness on the basis of the free-silica content of rock. The amount 06 free silica in materials used for rock dusting also has been limited.6/ Determination of free silica or quartz, therefore, is important.

Jan 1, 1940

By Fred D. Wright

Some new equipment for drilling vertical holes, cleaning blast holes, hauling explosives, and conditioning Diesel exhaust gas has been developed. at the Bureau's Experimental Oil-Shale mine near Rifle, Colo, The equipment has application, not only in oil-shale mining, but in many of the country's underground mines in which room-and-pillar methods of mining are employed. This report presents the Bureau's experience in testing the following equipment in the Experimental Oil-Shale mine: 1. A four-drill benching jumbo for drilling 23-foot vertical blast holes 2. A jet borehole blower for efficient cleaning of deep, vertical blast holes. 3. An explosives truck equipped with two compartments to provide safe conveyance for dynamite and detonators. 4. A mobile, electric substation to provide switching equipment, low-voltage and overload protection, and transformer facilities to remote locations in the mine. 5. A chemical conditioner for scrubbing the exhaust gases from Diesel-powered equipment used in underground operations. 6. Other units of equipment which have been tested at the Experimental mine.

Jan 1, 1951