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By J. B. Gayle

The rate of oxidation of coals with nitric acid has been used by earlier investigators4 5 6/ for determining fusain and for studying petrographic composition. These workers accumulated considerable evidence indicating that, for coals ranging from lignite to low-volatile in rank, the method gives values for fusain that agree satisfactorily with those obtained by optical methods. One group5/even concluded that, when discrepancies are noted between results obtained by chemical and microscopic methods, the results based on the oxidation reaction are probably the more reliable. Unfortunately, after concluding that the method was valid, most of these workers apparently lost interest. As a result, no attempt to exploit or apply the method to problems of utilization has been reported. Recent studies of the influence of inert petrographic constituents on the properties of cokes made from various coals7/ have indicated a need for additional means of characterizing coals and blends used for carbonization.

Jan 1, 1960

By James A. Browning

Following an unsuccessful attempt earlier in the program to develop and market a drill channelling machine, we have designed and tested a new continuous channelling method which reduces operating sound levels to below 100 db. This new method relies on a small diameter oxygen-enriched burner to produce narrow channels. Sound intensities are reduced substantially compared to conventional channel widths. They are further reduced by a water spray directed immediately above the flame. Baffles placed along the top of the channel will reduce sound levels to below 90 db. Cutting rates are greater than those of existing channelling burners with costs per unit of channel area substantially reduced for those cases where oxygen costs are reasonable.

Jan 1, 1981

By Andrew K. C. Wong

Hydraulic transport has been considered as one of the most economical methods in transferring granular materials over relatively long distances. In the natural world, it is used to transport basic material required for the support of life; in industry, it is a method widely adopted for handling materials. But the phenomena of hydraulic transport has not yet been thoroughly understood. As most of them are conditioned by a number of hydraulic and mechanical parameters, of which the basic relationships are not fully known, the traditional approach in relating these parameters to the energy requirement is purely empirical in nature. Empirical formulas, such as that proposed by Durand, (1) only give satisfactory results over a selected range of (particle size)/(pipe diameter) ratios and slurry concentration. When the case is more complicated or when new situations arise, the empirical formulas fail to give good predictory results. In fact, most of these formulas are based upon dimensional analysis, where the underlying physical interaction is not explicitly considered. Apart from the loosely related, non-dimensional groups incorporated in the formulas, there is practically no analytical means for modifying the formula so as to enable it to cope with more complex real physical situations. Although it seems quite remote that a complete rigorous solution to this highly complex problem could be generated in the near future, it is generally recognized (2, 3) that research in this area should be directed to more comprehensive studies of the obscure phenomena. In fact, there are a good number of very basic problems such as the effects of gradation and concentration of particles upon

Jan 1, 1972

By L. R. Burdick

The Smokescope is an instrument recently developed for determining the density of smoke by shade comparison. The instrument is designed so that the smoke is seen adjacent to two shades of gray corresponding to Nos. 2 and 3 on the Ringelmann chart. Data on smoke density are important in the smoke-abatement field. The method that is specified and accepted as standard for smoke-density determination by the majority of city smoke regulations involves comparing the smoke shade with the four shades on the Ringelmann chart as published by the Bureau of Mines.2/ This investigation was made to determine the accuracy and convenience of the Smokescope. It was conducted as a part of the Bureau I s air-pollution work, which includes the study of techniques that will promote smoke abatement. The accuracy of the Smokescope was arbitrarily defined as the difference between the Smokescope determinations and the determinations by the accepted, standard method and was expressed as Smokescope correction. Although the corrections obtained were strictly correct only for the two observers and the Smokescope of the investigation, they indicate what might be expected from any observer who uses a Smokescope with reference shades that duplicate those of the test instrument. The report is devoted largely to the data on Smokescope correction, which were taken from a single stack under controlled smoke conditions. Field work, which was done at various locations with different stacks, is mentioned briefly in connection with the comparison of the convenience of the two methods. The data for estimating Smokescope correction were taken for the three variables that were expected to affect the results, namely, the density of the smoke, the amount of light, and the color of the sky behind the smoke.

Jan 1, 1955

By R. A. Isberg

This report describes the design and implementation of UHF radio and closed-circuit television systems in the Black River room and pillar limestone mine near Butler, Pendleton County, Kentucky. Prior to designing the radio system, measurements of signal attenuation on 812 and 466 mHz were made in the slope tunnel and in the straight and level crosscuts in the mine. Two distributed antenna systems fed by two sets of base stations provide approximately 75o coverage of the mine. Passive reflectors are used for extending signals into intersecting crosscuts and two-way signal boosters will be used to extend signals to the perimeter and obstructed areas of the mine. Fourteen mine vehicles were equipped with mobile radios equipped with digital identification, alarm and status encoders. Fifteen portable transceivers also were used. Six closed-circuit television cameras provide surveillance of critical transfer points of the belt conveyor system, and the loading dock at the base of the slope and an ash disposal area in the mine. Two-way radio communication and closed-circuit television have saved considerable man. hours, increased production, reduced maintenance costs and enhanced safety. Innovative developments were the use of passive reflectors and two-way signal boosters for extending signals into intersecting crosscuts, development of lightweight signal margin measuring equipment, modifications of mobile digital encoders to automatically send status information from mine vehicles such as numbers of loads of ore delivered, hot engine, etc., and the use of CATV technology for multiplexing audio, digital and video signals onto coaxial cables from the surface to the mine.

Jan 1, 1981

By W. K. Kleysteuber

This report covers the design and testing of a novel bulk materials conveying device by the Bureau of Mines. The transport concept of the device is to create a traveling wave with a steep front so that the bulk material slides and cascades down the front of the wave with some horizontal motion. Ideally, the front should act like a continuous chute. The concept of moving bulk materials along a belt without any forward movement of the belt itself was demonstrated. The conclusions reached were that the mechanism as designed could not overcome the inherent major disadvantages that would make the undulatory conveyor suitable for practical applications.

Jan 1, 1974

By R. H. Nielsen

A new, cheaper precipitation scheme has been developed to produce purified zirconium oxide, Technical-grade sulfuric acid is used to precipitate a basic zirconium sulfate from a hot dilute hydrochloric acid solution. With close control of temperature, pH, and zirconium - sulfate ratio, excellent purification and complete zirconium recovery can be attained. The process has been successfully applied for 3 months and has proved to be a more satisfactory procedure than the ammonium phthalate process used previously. INTRODUCTION The Northwest Electrodevelopment Laboratory of the Federal Bureau of Mines has developed and improved the Kroll process for the production of pure ductile zirconium and hafnium. metal. Since 1946 over 1 million pounds of zirconium sponge metal has been produced, mostly high-purity material for the Atomic Energy Commission

Jan 1, 1956

By F. W. Wood

The use of consumable.-electrode arc melting as a production technology is growing. One advantageous feature of this process is that it avoids ingot contamination by soluble crucible materials by employing a chilled metal crucible. Because the thermal balance under these conditions is rather delicate and does not necessarily provide a favorable environment for solidification, catastrophic imbalances can occur. The effectiveness and mechanistic roles of various factors are mostly unknown, and more intelligent insight regarding the distribution of temperature and heat is needed. Experience has provided several pertinent observations, some of which are quite superficial. The most meaningful data have resulted from studies of molten pool shapes and sizes and from measurements of heat flow through crucible walls. Overall experience, intuitively interpreted and supplemented, is sufficient nevertheless as a basis for a boundary-value treatment of the problem. A mathematical analysis based on a separation of variables, using conventional differential equation methods, provides a useful solution. For a cylindrical ingot, the temperature varies as a Bessel function of an argument proportional to the radius and as an exponential function of longitudinal position. Trial calculations using the problem solution seem to verify the general correctness of the result as compared with experience. The role and nature of solution parameters are also clarified, though not entirely resolved. It is revealed that the barrier to heat flow at the ingot-crucible surface has a prominent influence. Utility of the model embodied in the problem solution is readily demonstrated by considering a variety of contemporary questions about arc melting, and it is hoped that utility can be enhanced by improvement of the model.

Jan 1, 1968

By R. S. Rosso

A program to investigate the effects of hardened washers on the uniformity of roof bolt tension and the resulting ground control in an underground mine was carried out. The complete roof bolt installation and roof bolt loads, mine convergence, and bed separation were monitored for a period of five months. The results show no evidence to support or refute the theory that mechanical roof bolts offer better support when they are installed with a high uniformity of tension. Also shown is the fact that if the bolts are installed with a maximum deviation from the mean torque of ±15% the addition of hardened washers significantly improved the uniformity of the installed tensions in the roof bolts.

Jan 1, 1977

By G. S. Rice

The recommendations of the Bureau of Mines on rock-dusting practices are embodied, except in a few details, in the Recommended American Practice for Rock-Dusting Coal Mines to Prevent Coal-Dust Explosions,5 approved by the. American Engineering Standards Committee,6 December 30, 1925 It is specified that the dust to be used is of a size that all will pass through a sieve having 20 meshes per linear inch and that 50 per cent or more will pass through a sieve having 200 meshes per linear inch.

Jan 1, 1930

By S. H. Ash

The United States Bureau of Mines has published relatively little on the flooding and unwatering of coal and metal mines. Bulletin 229, Fifty-Nine Coal-Mine Fires, published in 1927, contains several instances of the flooding of mines or sections thereof to extinguish fires but does not describe their unwatering. Report of Investigations 2649, Explosion Hazards Incidental to Unwatering Coal Mines, published in 1924, warned against the possibility of gas accumulations in flooded mines and indicated the precautions to be taken. Report of Investigations 2255, An Unusual Hazard in Reopening Long-Flooded Timbered Metal Mines, published in 1921, told of methane being pocketed and the danger thereof. The flooding of mines originates in many ways. At some mines flooding followed reopening after what was thought to be permanent abandonment; also, explosions have caused some mines to be flooded. Extinguishing fires, accidental encountering of underground streams or flooded old workings, and caves of strata admitting water from underground workings, water-bearing strata, or surface accumulations have also flooded all or parts of mines. Unfortunately, un watering often necessitates much study and causes apprehension largely because experiences in similar situations are not generally known, as few descriptions of successful or unsuccessful methods are available. The job has sometimes been contracted for outside the local management involved and has become a matter of record for the contractor only. As the cost-plus contract system often employed in the past is now known to be expensive, careful managements elect to handle the problem themselves, in line with the general policy of cutting expense where possible. This report describes specific in-stances of successful unwatering by operators.

Jan 1, 1933

By D. Harrington

Fire is always a serious-menace, whether in a residential or in an industrial region; in wartime it is particularly damaging in an industrial plant. The mining industry is especially vulnerable, as its plants are generally more or less isolated front centers of population and do not have access to modern fire-fighting equipment; moreover, owing to the transitory rapture of most mines, their surface structures; are often relatively flimsy and flammable.. Trained firemen seldom are available at or near mining plants to teach the fundamentals of fire-fighting to local fire brigades, with the result that efficiency in combating actual fires is lacking. Often the attitude "it can't happen here" is held by the management of a mining property, unless the plant has suffered a serious fire; even then lapse of time is very likely to induce forgetfulness as to the possible hazards. The necessity for producing metals for the prosecution of this war has increased management's responsibility. Whereas heretofore the loss of a plant or mill by fire meant merely monetary less to the stockholder of the company, now the national interest is affected, in that the nation suffers from loss of production of minerals indispensable for war purposes.

Jan 1, 1943

By William G. Pariseau

The research reported here concerns a four year study of the rock mechanics aspects of two underground hardrock mine study stopes. The first study was conducted at Anaconda Minerals Company's Carr Fork Mine near Tooele, Utah. The second study was conducted at the Homestake Mining Company's Homestake Mine In Lead, South Dakota. Both case studies were cooperative efforts of mining company personnel, the Spokane Research Center of the Bureau of Mines and the Department of Mining Engineering, University of Utah. Large diameter (6 1/2 In.) blastholes were an integral part of the stoplng method at each mine. A true vertical crater retreat (VCR) method was used at the Homestake Mine, while a vertical bench mining method (VBM) was used at the Carr Fork Mine. VCR and VBM methods were developed In the 1970's; they offer significant productivity gain and are now used throughout the world. The new technology, however, brings with It a requirement for more sophisticated engineering design and control. Since there are no personnel in a VCR or VBM stope, all ground control Including dimensioning of stopes and pillars and the layout of cable bolt assays or other artificial support must be done in advance of production blasting. Accordingly, the objective of the research study was the establishment of a procedure for optimizing stops and pillar sizes. The approach taken was In each case a combination of mine measurements of the study stope response to mining, laboratory testing for rock properties and In situ stress measurements of the premining stress field, and theoretical calculations of the study stope response to mining. All calculations were done with the UTAH-II finite element computer program. Simulation of the blasting sequence gave a correlation of 0.88 between measured and calculated extensometer readings (Incremental relative displacements) at the Carr Fork Mine where other 30 Instrumentation boreholes were used to monitor the test stope response. A correlation of 0.84 was obtained at the Homestake Mine where 19 instrumented boreholes were used for monitoring purposes. These high correlations validated the computer mode and calibrated It for rock mass properties. The calibrated model was then used In parametric studies of alternative design layouts.

Jan 1, 1985

By H. L. Gibbs

Many factors contributed to the decision to build a radiochemical laboratory at the Salt Lake City Metallurgy Research Center to investigate the application of radioactive isotopes and chemical compounds in extractive metallurgy. These reasons included the notable success achieved in biological sciences with radioisotopes, the development of reliable instruments and methods for identifying the isotopes and measuring their activities, and the commercial availability of radioisotopes in a variety of forms and known activities. The paramount reason, however, was the realization that better methods were needed for guiding and quantifying research to resolve the complex extractive metallurgy problems under study at the Research Center. This is the first of a series of reports describing the application of radioisotopes and radioactivity techniques in extractive metallurgy. The report includes a discussion of licensing and safety requirements, a general description of the laboratory and the methods used, a definition of the nature and scope of the research program, and a synopsis of the more important problems studied. Subsequent reports will concern radioactive techniques for solving specific problems in mineral dressing, hydrometallurgy, and pyrometallurgy.

Jan 1, 1960

By Paul Hughes

This paper describes a focus of work presently being conducted at the Rock Mechanics Research Group at the University of British Columbia. The underhand method under consolidated fill ensures a high recovery under an engineered back that is comprised of cemented rock fill and/or cemented paste fill. This method of mining has been employed successfully in mines throughout North America as a method of mitigating exposure to the operator having to work under a seismically active ?back?. This paper reviews design methodology in the placement and analysis of sill mats with reference to site observation coupled with on going numerical and analytically derived solutions.

Jan 1, 2006

By E. M. Frost

"Helium has great value to the oil and as industry as a tracer gas, according to tests just completed in the Elk Hills Field, Naval Petroleum Reserve No. 1, Kearn County, California. When used as .a tracer gas, small percentages of helium are mixed with natural gas pumped into a reservoir for conservation, repressuring, or cycling purposes. Because minute quantities of helium added to natural gases can be detected by analytical methods and accurately determined, the variations of the helium content of gas withdrawn from various parts of a field when helium has been added to the injected gas give interesting and long-sought data on the movement of injected gas through reservoirs.The Bureau of Mines engineers began their studies of the use of helium as a tracer material in gas-injection operations in the Elk Hills, California, oil field, Naval Petroleum Reserve No. 1, in response to a request by the Navy Department for assistance in connection with an expanded oil-production program instituted in that field. This report discusses the Bureau's work on the problem of determining the direction and extent of migration of injected gas in the Elk Hills reservoir by the use of helium as a tracer gas,The Bureau appreciates the cooperation and assistance of Commodore W. G. Greenman, U.S.N., director, and Commander R. Walling, U.S.N.R., Assistant director, Naval Petroleum .and Oil Shale Reserves, Washington, D. C., Captain H. P. Stolz, U.S.N.R., commanding officer, and Commander F. G. Taves, U.S.N.R.., of the Navy's Elk Hills staff. The Bureau also appreciates the cooperation and assistance given by V. O. Wankowski, F. C. Tratt, Marray Putnam, Dana Champion, and other personnel of the Standard Oil Co., of California, operators of the Elk Hills field.R. A, Cattell, chief, and C. C. Anderson, assistant chief, Petroleum and Natural Gas Division; C. W. Seibel, supervising engineer, Bureau of Mines Helium Plants; and H. H. Hinson, petroleum engineer - all of the Bureau's staff - furnished valuable advice and assistance during the course of the work. H. C. Miller and G. B. Shea of the Bureau's San Francisco Office contributed valuable liaison work. The writer wishes to express appreciation to all these people for their cooperation and assistance."

Jun 1, 1946

By W. T. Abel

Laboratory tests were conducted with a closed, recycling system to evaluate the effectiveness of solid-in-gas suspensions as heat transport mediums. Micronized graphite in helium or nitrogen was circulated by a centrifugal compressor to determine the feasibility of the method and heat transfer capabilities of the mediums. Suspensions were circulated without plugging or eroding the compressor or piping. At low flowrates and light (0.1 to 0.2 volume-percent) graphite loadings, slightly less power was required to transport a given amount of heat with suspensions than with helium alone. Graphite deposition on the heat exchange surfaces of the cooler decreased the heat transfer effectiveness at higher solids concentration. Efforts to eliminate deposition are described.

Jan 1, 1963

By Wilson Blake

The Bureau of Mines used a mathematical model based on the finite element method of stress analysis to calculate stresses and displacements surrounding an open pit mine in a gravity-loaded rock mass. Comparison of the finite element solution for a semicircular notch in a gravity-loaded plate with the theoretical solution for a semicircular notch in a plate under uniform compression parallel to the free boundary demonstrates the inapplicability of the latter method to openings at the free surface of a gravity-loaded medium. High stress concentrations are formed at irregularities along the boundary of an open pit in a gravity-loaded continuous competent rock; however, for this type of rock the magnitudes of the stresses are too low to be considered a major factor in open pit slope stability. High stress magnitudes will occur if, in addition to the gravity stress field, a large horizontal stress field exists.

Jan 1, 1967

By Curtis D. Edgerton

Miami Oölite limestone is the only significant construction mineral in southeastern Florida. Its source area coincides with that of rapid urban expansion. Two-thirds of the existing resource is already unavailable because of development. Land-use conflicts place future availability of limestone in jeopardy. However, a sufficient limestone resource to meet demand for many years is present if its extraction is not restricted. Adverse environmental effects of quarrying Miami Oölite are not severe; land values often increase following quarrying. Future availability depends upon--(l) achieving uniformity of Federal, State, county, and municipality statutory requirements governing quarry operations; (2) setting aside specific land areas for future quarrying; and (3) cooperative planning to provide for land utilization upon completion of quarrying.

Jan 1, 1974

By George C. Price

The Bureau of Mines conducted this study in the Roslyn No.5 coalbed in the State of Washington to determine the feasibility of mining hydraulically the portion of the coalbed that was steeply pitching. All of the experimental mining was done while advancing raises and rooms. A Bureau-developed hydraulic mining machine was used successfully in the pitching coalbed. It consisted of a remotely controlled monitor mounted on a self-advancing roof support unit of the type commonly used for roof support in longwall mining systems. The coal cutting rates averaged 0.73 and 0.54 ton per minute in raise and room mining, respectively, while using water volumes up to 230 gpm at a pressure of 4,000 psig. Productivity averaged 4.7 and 5.2 tons per man-shift for raise and room mining, respectively, compared with 7.5 and 8.5 tons per man-shift, respectively, by conventional hand mining methods.

Jan 1, 1965