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By C. H. Elder, Maurice Deul

Coal degasification boreholes drilled from the surface have been success - fully hydraulically stimulated to increase the flow of gas from the coal. This Bureau of Mines report describes the hydraulic stimulation procedure for a coalbed, the equipment required, and design criteria for the treatment. Three examples of stimulation treatment show from fivefold to twentyfold increases in gas production. The tests were conducted in the Pocahontas No. 3coalbed, Buchanan County, Va., the Pittsburgh coalbed, Washington County, Pa., and the Mary Lee coalbed, Jefferson County, Ala. Two sites where the coal was hydraulically stimulated and exposed by subsequent mining show no adverse effect on mining operations through the treated zones. The induced vertical partings were confined to the coalbed and did not in any way affect either roof or floor rock.

Jan 1, 1975

By Tony Keller, Setsuo Maeda

Hand-Arm Vibration Syndrome (HAVS) was identified as early as 1918 in Bedford, Indiana in the U.S. Since then much research work has been done around the world in the areas of medical, epidemiological, engineering and legal aspects of HAVS. In Japan, much of the pioneering work in this field has been performed by Dr. Setsuo Maeda and his staff at the National Institute of Industrial Health (NIIH) in Kawasaki. Most recently, reports of work done by this group and by Dr. Ren Dong1 of NIOSH in the U.S., as well as many other suppliers and Japanese practitioners were presented at the 13th Japan Group Meeting on Human Response to Vibration held in Osaka2 during August 3-5, 2005. [ ]

Jan 6, 2006

By Bowles Oliver

"Modification of Quarry Process.Limestone beds are formed by processes of nature, processes that have been in operation for thousands and perhaps millions of years. Therefore, their com- position and physical properties are long-established and unalterable features over which man has no control. He must take them as he fields them.It is undoubtedly true that the character of lime depends largely on the nature of the parent limestone. A high-calcium lime cannot be manufactured from a dolomite, nor can a pure lime result from the calcination of an impure raw material. However, in the process of turning limestone into lime man is not entirely helpless in his control of quality. Even though a deposit is variable in character a single lime product of uniform quality may be produced by judicious quarrying. A single grade of product may not always be desired, the producer may wish to supply the needs of a variety of users each demanding U different grade or quality of lime such a series of graded products may be produced in part at least by modifying the quarry method. Thus, by changes in quarry practice a single product or a variety of products may be made. The latter problem will be considered at a later time, and the present paper devoted to the first named question' that of producing a single grade of lime from a deposit of variable rock,It is realized of course that uniformity in the product is influenced greatly by manufacturing processes such as calcining' hydrating' grinding or storage, but the present discussion is confined to the influence of raw materials only. In considering the various devices that may be employed it is realized that much remains to be learned, and it is hoped that many operators will contribute to the discussion as they have already done in connection with previous papers of this series."

May 1, 1923

By F. R. McDonald

This report presents a discussion of the spectra of 39 condensed thiophenes in which the structure includes at least 1 benzene ring. The vibrational bands present in three regions of the infrared spectra of these thiophenes were interpreted by comparing the similarities of the spectra of condensed thiophenes with the spectra of substituted benzenes. In the overtone-combination region 23 of the 39 condensed thiophenes had spectra which contained sufficient detail to be usable for correlating this region of the spectrum with the appropriate benzene spectrum. In the in-plane deformation region it was possible to make correlations for the vibrations of 18 of the 39 condensed thiophenes whose infrared spectra were studied. In the out-of-plane deformation region the C-H out-of-plane vibrations for hydrogen on benzene rings in the condensed thiophenes can be correlated using known data from substituted benzenes.

Jan 1, 1967

By T. G. Carnahan

The Federal Bureau of Mines investigated, on a laboratory scale, a technique for recovery of silver from pregnant solutions generated in the hydro-metallurgical treatment of complex base-metal sulfide concentrates with oxidizing chloride media. This technique provides a means for recovery and simplified reduction of accessory silver to metal from chloride solutions. The method consists of adding NaI or KI to the solution to precipitate AgI, which is then contacted with Na2S to produce Ag2S and to regenerate the iodide salt solution. Silver recoveries range from 99 pct with 20 pct excess iodide precipitant, to 92 pct when the theoretical stoichiometric amount of precipitant is employed. The Ag2S product can be reduced to silver metal by contact with aluminum chips in NaOH solution followed by purification with conventional fire refining techniques.

Jan 1, 1980

By Thomas P. Mucho, Dennis Dolinar, Christopher Mark

During the 1990s, the former U.S. Bureau of Mines conducted a number of field studies in which the performance of different types of roof bolts were evaluated in different geologic environments. The studies used a standard suite of measurements, including multipoint extensometers, strain-gauged roof bolts, and roof bolt load cells. The sites were chosen to investigate the effect of a variety of parameters, including installed tension, bolt capacity, grout annulus, and horizontal stress orientation. Although not fully successful, the measurements provided valuable insights into each of these issues. They also showed that instrumentation and monitoring have important advantages over observational methods for comparing the performance of different roof bolting systems.

Jan 10, 2000

By W. A. Selvig

The experiments described herein were made at the request of Committee D-5, on Coal and Coke, American is n Society for Testing Materials, in order to obtain data as to the probable contamination of laboratory samples of coke Then pulverized to pass a No. 63 sieve of tine U. S. Standard Sieve Series2 by methods other than by ball-mills or hard-steel diamond mortars, which methods are specified-in the standard methods of that Society.3 After pulverizing, representative samples were analyzed by the Bureau of Mines at Pittsburgh for ash content to detect any contamination of the samples by the pulverizing apparatus. Preparation of Core Samples for Tests. Two samples of 48-hour beehive coke (Continental and Leisenring) made from Pittsburgh coal were selected for the tests. These cokes were crushed approximately to No. 10 sieve size, by first passing through a jaw crusher and then through a, roll crusher. The crushed coke was then carefully mixed and riffled into portions of about 800 grams each, and sent to three cooperating laboratories for grinding, through a No. 60 sieve. Size tests on these samples shoved the fineness to be as follows: [ ]

Jan 1, 1925

By A. T. Coumbe

The Bureau of Mines has compiled pipeline mileage every 5 years since 1926, with the exception of the war period 1941 to 1949. The present survey has been made to reflect the progress under mobilization of the petroleum pipeline industry where efforts have been made by the government to stimulate construction of those facilities that would best equip the nation for a possible major emergency. This report summarizes the total mileage change 1n petroleum pipelines for 1950 through 1952. In order to increase the value of the information gathered the reporting companies were requested for the first time to report not only the net change in mileage as formerly, but also all new and used pipe laid and the total taken up. This new information permits effective appraisal of the construction effort of the industry and relates it to steel requirements.

Jan 1, 1953

By L. C. IlsLey

A n'Ulllber or operators have installed f'lBJ!le-proot or so-called exploaion­ proot electrical outfits, under the impression that such equipments met· all of the reqiirements of the Bureau of Mines as regards safety, There a.re todq in gaseous mines a large nwnber of euipments that have not been approved by the Bureau ot Mines, and unless mod1f'iecl could not receive sucl1 approval.. These e qu.ipments represent in pa.rt the product of manufacturers whil ha.ve never submitted. equipments for insri?ction or tests. and iri pat types developed. previous to the safety work or the bureau. Sometiu.es saleimen advocate the use of unapproved. types in gaseous mines in place of Bureau of Mines approved outfits, the purchase price beini slightly less than approved types,

Sep 1, 1922

By Perry G. Cotter

As a portion of a general program for the synthesis of hard materials, a method was sought by which the hardness and density of tungsten carbide (WC)-cobalt compacts could be increased. It was demonstrated by Cotter that these improvements in quality could be made by employing an electric-resistance sintering process in which heat and pressure are applied simultaneously to presintered compacts composed of powdered tungsten carbide and cobalt. This conclusion was based on tests of material prepared by Cotter on welding equipment in use at the U. S. Naval Engineering Experiment Station, Annapolis, Md., and at Rensselaer Polytechnic Institute, Troy, N. Y. Rockwell-hardness tests made at Norris and core-drilling tests made at the Mount Weather Station of the Bureau of Mines indicated that, for some purposes, carbide material made by this process might be superior to the chemically analogous commercial products prepared by ordinary sintering methods. A program to develop optimum conditions for the electric-resistance sintering of tungsten carbide-cobalt compacts was initiated. The program was followed by a systematic evaluation of the hardness and density of compacts prepared by this method along with a series of carbide compacts furnished by various manufacturers. This paper presents a description of the electric-resistance sintering of tungsten carbide-cobalt compacts and the results of comparative physical tests.

Jan 1, 1955

By Ann G. Kim

Samples of gas were obtained directly from the coalbed during drilling of horizontal and vertical boreholes in six different formations. The samples were analyzed by gas chromatography for C1 to C5 hydrocarbons and for O2, N2, H2, He, and Co2. Methane in the gas varied from 63 to 99 percent; carbon dioxide from 0.1 to 15 percent. The CH4/CO2 ratio varied and showed no apparent correlation with age, rank, or bed. The majority of samples contained ethane, propane, and butane; hydrogen and helium were found in some samples. Oxygen and nitrogen were usually present, possibly as a result of air contamination. A more extensive sampling program would be necessary to establish relationship between the amount and composition of the gas in the coalbed and other factors.

Jan 1, 1973

By C. J. Mains

The gas -flow oil-shale retort is a continuous, crass flow, gas -to -broken solid heat-exchange system in which heat is transferred by convection from the gas to the solide.2/ This type of heat transfer presents a problem of analysis that cannot be solved by methods in common use. Solution of this problem is necessary for design, operation analysis, and predict ion wherever that type of heat exchanger is used. This report embodies a method for calculation of heat transfer coefficient and temperature histories of gas and solid in the gas- flow retort operating at equilibrium conditions. Detailed calculations are presented to show the application of the method explained in this report to conditions of an actual run made in the gas-flow retort. Although used here for a specific case, the method is applicable to all heat exchangers that are characterized by continuous, crossflow, gas -to-broken solid heat transfer. INTRODUCTION In any direct, gas -to -broken solid heat -transfer system, it is difficult to measure the temperatures of the gas and solid inside the heat exchanger. The driving force for heat transfer between the two media in the bed there- fore usually is unknown. The major resistance to heat transfer is in the gas film surrounding the solid particles, and the thickness of this gas film is neither uniform nor can it be determined readily. It is well to point out also that determination of the surface area of the particles is of poor accuracy. Since the driving force, the major resistance, and the surface area in the heat-transfer system are such uncertain quantities, It is not feasible to calculate the heat transfer by usual methods. All of the fore- going statements are true of the gas-flow retort; as a result, efforts were made to determine apparent heat-transfer coefficients and temperature histories of gas and solid in the heat -exchange bed by calculation using those data that were available. The heat -transfer coefficient calculated has the following dimensions: B .t .u. per second, °F., cubic foot of bed volume, where heat - transfer coefficients normally have the units; B .t .u . per hour, square foot, °F. Only the Schumann-Furnas formulas may be used to determine the heat- transfer coefficient and temperature histories in this type of heat exchanger.

Jan 1, 1953

By F. W. Davis

For some years this subject has been of interest to metallurgists. Previous to the War some work was done in :Belgium. on the enrich.ntSnt of the blast with oxygen i.."'l. connection with the smelting of iron orei.; in the blast furnace. In the United States, the late .J. E. ,Joh."lson, .Jr., \ve.s :interested in the possible use of 0J1.:ygen for metallurgical operations ar.:i cerried on some experic:.ental work along these lines pre..,,-ious to his de.e.hft Dr. F. G. Cottrell, formerly Director of the :Bureau of Mines, De7?,H''(;:,-of,,:a:t: of the Interior, and now Direc'cor of the Fixed lifi trogen Itesearc:l-1 La -:c r;a.-o='Y, Depart­ment of .Agriculture, first directed. the Eurec:ru 1 s attention to this subject. When it first began this work, the Director of the Burea.t1. of Mines, beca11se of his interest in this investigatio:::i, asked :Mr. M. H. Roberts: Vice-President of the FraU:din Railway Supply Company to select an Advisory Corr:nittee to work with the BJ::eau on tl1is subject; it also asked Mx-. Robez·ts to act as Cha.irman of this C<)1.,_1l!lHtce. T!le personneJ. of the Comrnitee which was selected. by r. Roberts is as follows:

Jul 1, 1923

By P. L. Loyselle, B. D. Comilsen, D. H. Carlson, J. H. Johnson

"In-mine airborne particulate samples have been successfully collected and the relative amounts of diesel and coal determined using the Laser Raman Quantitative Analysis (LRQA) method. This method allows analysis of filters which have been collected by a method similar to that used to determine the airborne respirable dust concentration in us underground coal mines. Samples were taken near the feeder-breaker, on haulage vehicles, and in the returns. Sampling methodologies were developed for coal-only and diesel-only particulate reference samples with sufficient filter loading for the LRQA method. A statistical analysis of reproducibility has been carried out. Samples have been collected simultaneously at two locations using the LRQA and the size-selective sampling methods. Good agreement between the two methods has been found.INTRODUCTIONThe goal of this research has been to develop the Laser Raman Quantitative Analysis (LRQA) method to measure the composition of respirable particulate, i.e. the fractions of coal and of diesel particulate, in the mine ambient air. In earlier Bureau of Mines sponsored research, we successfully demonstrated that the LRQA method could be used to measure the fraction of Diesel Particulate Matter (DPM) in coal/diesel particulate mixtures which were prepared in the laboratory.(I) 'The immediate objective was to test and refine this LRQA method on samples collected in a diesel underground coal mine.Specific objectives required to meet this goal include:I) Develop in-mine sample collection methods which will insure sufficient particulate loading on filters for LRQA. ,2) Develop methodology for in-mine collection of reference samples (""coal-only"" and ""diesel-only"" filters) which arc required for quantitative LRQA. 3) Analyze precision and accuracy of the LRQA method. 4) Compare composition measurements with another analytical method, i.e. the University of Minnesota/Bureau of Mines size selective sampling Micro-Orifice Uniform Deposit Impactor (MOUDI) method.An advantage of the LRQA method is that it allows analysis of filters which have been collected by a method similar to that used to determine the respirable dust concentration in US underground coal mines. No new sampling instruments and techniques are required. Transfer of sample from collection substrate to analysis substrate is not necessary. Furthermore, other analyses can be made on the same sample since the technique is nondestructive."

Jan 1, 1988

By W. E. Miller, G. S. Scott, G. W. Jones

"INTRODUCTION One of the major activities of the Bureau of Mines is the promotion of safety in mining and the mineral industries. Research is undertaken in connection with these problems to determine the explosion and ignition hazards of combustible gases, liquids, and solids and to investigate means of reducing them.Occasionally the Bureau is asked to determine inflammability or ignition temperatures to enhance safety in nonrnineral industries. From time to time it has complied with such requests when no other agency was available to do the work and the investigation could be conducted with a minimum of time and expense. The present investigation is one of this class.Nicotine (C10H14N2), a colorless combustible liquid having a boiling point of 246°C, is usually obtained from tobacco and its products by extraction processes. When heated to its boiling point it decomposes; the purified product is obtained from tobacco extractions by distillation at reduced pressures or is distilled in a current of inert gas.It has an unpleasant odor, a burning taste, and in the undiluted state is highly toxic. Under certain conditions it can be oxidised to nicotinic acid and in the near future may therefore become of considerable economic importance. Nicotinic acid is a component of the vitamin B complex now commonly used to fortify white flour and other foods that normally are deficient in these vitamins."

May 1, 1942

By Thaddeus B. Evans

This information circular is one of a series describing mining methods and costs, being published by the Bureau of Mines. The Sunbright mine of the Foote Mineral Co. at Sunbright, Va., is the southernmost underground limestone mine in the State. It is a comparatively recent operation, and a description of its rapid development to production stage may have particular interest for the limestone-mining industry. ACKNOWLEDGMENTS Acknowledgment is made to the executives of the Foote Mineral Company including F. B. Shay, vice president in charge of production, W. B. Towner, general production manager; and to the members of the company staff at Sunbright for their assistance in preparing this paper.

Jan 1, 1957

By T. E. Purcell

(a) Moisture. - Moisture, "as fired," is specifically significant in pulverized-coal firing because of its effect upon the continuity of raw-coal feed to the pulverizer, pulverizer capacity, flame stability, and speed of ignition. The extraneous moisture content is a rough index of potential difficulties in unloading and maintaining the flow of raw coal to the pulverizer and of pulverized coal to the furnace, with the troubles increasing geometrically as the percentage increases. Sticking or other stoppage of coal flow at any point between the bunker and the furnace is especially serious with pulverized-coal firing because there is danger of immediate loss of output. Where moisture is a problem, the designer must exercise great care in the design of coal-handling and preparation apparatus.

Jan 1, 1951

By George S. Rice, J. W. Paull, R. R. Sayers

"Standard rock dust for use in the rock dusting of coal mines might be defined tentatively as powdered mineral, light colored and free of carbonaceous matter and free silica, all of which will pass a 20-mesh screen while 50% of it will pass-through a 200-mesh screen.Such dust may be prepared from limestone, gypsum, anhydrite, or shale free of sand and flint. For the initial rock dusting of the average nongaseous bituminous mines enough standard rock dust should be applied so that the combustible content of the resulting mixture of rook dust with mine dust shall not exceed 45%, a range somewhere between 35% end 45% being the practical objective sought.All entries, slopes or passageways and room necks should be rock dusted.Additional safeguards are:a.,Rockdusting roomsb.,Scattering of dust in vicinity of shots before firing.c.,Placing of barriers in the mouths of panels, cross-entries and other key positions.Redusting becomes necessary whenever the combustible content of the mine dust exceeds the permissible maximum. This should be determined by regular, systematic sampling, followed by a simple analysis of the samples for combustible content. A Bureau of Mines volumeter for measuring the density can be used for the determination of combustible content."

May 1, 1924

By A. B. Hooker, L. C. IlsLey

"Field inspections and data relative to the use of rubber—sheathed trailing cables in mines show that much cable is ruined or its probable life shortened by being overheated in service.The length of cable required to make connection from a source of supply to a machine at the face workings may be 100 to 500 feet. As a rule, the cable is carried on a reel and unreeled as required; and thus in most cases some of the cable is not removed from the reel. The overheating generally occurs in that part of the cable which is left on the reel.Factors that determine the heating of trailing cables are:1. The size of the conductors in the cable.2. The maximum energy to be supplied through the cable, based upon the horsepower of the motor and the degree to which the motor is loaded.3. The voltage of the supply and the variation of the voltage at the receiving4. The time length of current flow and whether continuous or intermittent.5. The kind of current (direct or alternating).6. The amount of cable left on the reel.7. The type of cable used.8. The kind of reel used.In connection with an investigation of the general performance of rubber—sheathed trailing cables, the Bureau of Mines has made a limited study of some of these factors, including the following points:"

Jul 1, 1931

By D. W. Frommer, M. M. Fine

"INTRODUCTION Laboratory mineral-dressing investigations covered by this report show that ores from Montgomery County, Ark., and Morgan County, Mo., are potential sources of barite and zinc. Fine grinding and froth flotation yielded drilling-grade barite from the former and chemical-grade barite and zinc concentrates from the latter.Samples from these deposits were subjected to a laboratory investigation to develop an economic and feasible treatment. The Arkansas ore, submitted by the Husky Refining Co., consisted of an intimate mixture of the economic mineral and quartz. Fine grinding and fatty acid flotation were utilized to effect a good recovery of a drilling-grade product. The other was a zinc-barite ore submitted by the Rocky Ford Mining Co., Stover, Mo. There was no problem in the recovery of zinc (most of which occurred as sphalerite), but the recovery of barite by flotation was complicated by the presence of gangue carbonates. Ultimately, an excellent recovery of barite was achieved with a relatively new type of flotation promoter, petroleum sulfonate.In recent years, barite has become one of the major industrial minerals as an essential ingredient in heavy drilling fluids, pigments, and chemicals. New sources of this important commodity are always interesting; thus, it is the purpose of this report to present information that may permit commercial exploitation of two deposits not in production."

May 1, 1952