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By Robert E. Wood

The compressibility factors, Z, of helium, nitrogen, and helium-nitrogen mixtures in the three-dimensional space of temperature, pressure, and gas composition have been related to the Leiden form of the virial equation of state. The dependency of virial coefficients through the fifth on temperature and gas composition has been established for the temperature range 133.15° to 748.15° K. Compressibility factors, Z, have been computed from the equation of state and tabulated as functions of gas composition, pressure, and temperature. Tabular values of Z are presented for 30.00 through 100.00 percent helium for temperatures from 240° through 700° R for pressures from 14.696 through 3,050 psia and for temperatures from 720° through 1,300° R for pressures from 14.696 through 1,500 psia. Tabular values of Z are presented at increments of 5.00 percent helium and 20° R, and, for pressures greater than 50 psia, at increments of 50 psi.

Jan 1, 1967

By M. A. Mahtab

This report presents the geometric parameters (attitude, spacing, extent, and aperture) of fracture patterns in a selected portion (study area) of San Manuel copper mine, Arizona. The geometric parameters are quantified for input to structural analyses for studies of the influence of fractures on cavability of ores. Using an orientation analysis procedure developed earlier by the Bureau, three prominent and nearly orthogonal sets of fracture orientations were delineated in the study area. Sets 1 and 2 dip nearly vertically, and generally strike east-west and north-south, respectively, whereas set 3 is nearly horizontal. Both a horizontal rotation (of 14° to 26° for sets 1 and 2, respectively) and a tilt (of 20° for set 3) is shown to occur between the 1415 and 2015 levels of the mine. Gomparison of the three major rock types present in the study area (quartz monzonite, monzonite porphyry, and rhyolite) show that the rhyolite is characterized by short extent, small spacing, and tightness of fractures as well as the general absence of fracture set 3, which may account for its generally observed strong resistance to caving.

Jan 1, 1973

By C. Harry Benedict

This paper, describing the leaching practice at the Calumet and Hecla mills, Lake Linden, Mich., is one of a series on milling methods and costs being published by the United States Bureau of Mines. GENERAL DESCRIPTION The reclamation plant is located along the shores of Torch Lake at a slightly lower level than the concentrator itself. The entire location of the original concentrator, in connection with the present reclamation plant, has been ideal, lore particularly as the leaching and flotation departments are common to both units. After 15 years of operation and with the reclamation sands just a little more than half exhausted it would appear that the remaining life of the deposit could be worked by the present plan, without decided changes or renewals of plant or equipment.

Jan 1, 1930

By Lowell Stroud

Since 1929, the Helium Activity of the Bureau of Mines has operated a helium-extraction plant at Amarillo, Tex. The natural gas that supplies this plant is obtained from the Cliffside geologic structure 12 miles to the northwest and over the years, has become known simply as "Cliffside gas," There is need for published data on the low-temperature phase equilibria of helium-bearing natural gases. To date, little information has been published on the equilibrium phase compositions, solution of helium in condensed natural gas, condensation characteristics, or equilibrium vaporization coefficients for methane, nitrogen, and helium in helium-containing systems. A windowed phase equilibrium apparatus (8)6 was used to obtain 105 equilibrium samples, representing 35 experimental conditions of condensed Cliffside gas at pressures of 100, 200, 300, 400, and 500 p.s.i.a. and temperatures from 0° to -270° F. Data on equilibrium vapor-liquid composition for Cliffside gas are presented in both tabular and graphic form and are discussed in detail to show their relationship to certain criteria that must be met to effect an efficient separation of helium from natural gas by means of low-temperature processes. Facts about condensation characteristics and solution of helium in the liquid phases are included, The important relationship of these two factors in decreasing the percentage of total helium lost by solution in the liquid phase is discussed.

Jan 1, 1961

By M. Paczkowski

The use of inert gas systems to extinguish mine fires has been the subject of research for some time in the United States. In some European countries, it is an established practice. Tests were conducted with the CMI Inert Gas System (CMI), which is being used by the Polish mining industry. This system utilizes a modified jet aircraft engine and afterburner as a compact source of combustion products with a very low (less than one percent) oxygen content. Water injected into the combustion products stream provides evaporative cooling and forms a mist with a high cooling capacity. The CMI system was used under controlled conditions to extinguish coal pile fires at the U. S. Bureau of Mines Experimental Mine in Bruceton, Pennsylvania. The test results show that the CMI system can be used conveniently to extinguish fires quickly and to maintain an inert atmosphere in the fire zone to prevent re-ignition.

Jan 1, 1982

By John Nagy

A study was made in the Bureau of Mines experimental coal mine of factors affecting gas ignition by a cutoff explosive charge. Experiments showed that, although gas could be ignited under some circumstances, the probability under normal mining conditions would be low. The use of permissible explosives, relatively short-delay intervals in firing adjacent holes, blasting to a 6-inch kerf, and reasonable care in the placement of the holes favor safe blasting and are current practice in mining. The experiments also showed that the weight of the charge is not a primary factor in the ignition of gas by a cutoff charge. The quenching action of a first charge on the igniting action of a second was verified in a supplementary study. Related experiments have shown that gas at the face may be ignited by a single charge of explosive when fired with a light coal burden. Permissible explosives were less hazardous under these conditions than nonpermissible explosives. The frequency of gas ignition in cutoff and single-charge experiments increased as the linear distance between the sheared face and the opposing mine rib increased.

Jan 1, 1960

By E. D. Gardner

The mine of the Eureka Standard Consolidated dining Co. is at Dividend, Utah, in the Tintic mining district. It is operated under the same management and controlled by the Antic Standard Mining Co.; the two properties adjoin each other. The Eureka Standard is worked through a vertical shaft; the ore is mined by a stringer-set-and-fill method. One hundred and thirty men were employed in April 1933. The normal daily tonnage is 100 tons; the ore is shipped to the smelter at Garfield, Utah.

Jan 1, 1935

By W. A. Selvig

"The purpose of the investigation described herein was to determine how closely different laboratories can check one another in making determinations of fusibility of coal ash with the De Graaf electric coal-ash fusion furnace: how well duplicate determinations by the same laboratory will check, and how the results with the De Graaf furnace compare with those of the standard gas-furnace method of the American Society for Testing Materials.4Thanks are due the following laboratories who cooperated in this study by making fusibility tests with the Do Graaf electric coal-ash fusion apparatus: J. J. Brennan, testing engineer, Northern States Power Co.; R. E. Gilmore, superintendent, Fuel Research Laboratories, Canadian Department of Mines A. T. Leavitt, president, and W. Mueller, chief chemist, Hamilton By-product Coke Ovens. Ltd.; Edgar Stansfield, chief chemical engineer, Scientific and Industrial Research Council of Alberta. Canada; and H. S. Vassar, laboratory engineer, Public Service Electric and Gas Co.The ash-fusibility determinations by the standard gas-furnace method were made in the Coal Analysis Laboratory of the Bureau of Mines at Pittsburgh under the direction of H. M. Cooper, associate chemist. The investigation was made at the suggestion of A. C. Fieldner, chief engineer, Experiment Stations Division of the Bureau of Mines.Routine determinations of the fusibility of coal ash are made in the laboratories of the United States Bureau of Mines by the gas-furnace method. This method was standardized after considerable experimentation5 on the nature of the fusion of coal ash and the various factors which affect its determination. The method was subsequently adopted by the American Society for Testing Materials as one of its standard tests."

Jun 1, 1930

By D. R. Brooks

The Bureau of Mines has tested a dewatering technique for phosphatic clay waste. The technique utilizes a flocculant, polyethylene oxide (PEO), that forms strong, stable flocs that can be dewatered on a static screen followed by further dewatering on a rotary screen or trommel. In field tests conducted in central Florida, clay wastes containing approximately 4 pct solids have been consolidated to greater than 20 pct solids. The rate at which PEO-treated material continues to dewater in a mine cut also was monitored. Preliminary results indicate that PEO-treated material will dewater to 30 pct solids in 80 days. Pretreatment of phosphatic clay waste with lime lowers the PEO dosage required for dewatering.

Jan 1, 1986

By Raymond B. Ladoo

Garnets are usually found well crystallized in the cubic system , the principal forms being rhombic dodecahedrons , tetragonal trisoctahedrons or combinations of the two , and hexoctahedrons . They also occur as rounded disseminated glassy grains and in compact massive , laminated or gramlar aggregates . They vary greatly in color , but the most common garnets , almandite and andradite , are most often found of a dark red or reddish brown color .

Apr 1, 1922

By H. R. Babitzke

To develop alloys suitable for use at elevated temperatures, columbium and tantalum were combined with tungsten, hafnium, vanadium, zirconium, and titanium, and the resulting alloys were evaluated with respect to fabricability, hardness, Electrical resistivity, strength at elevated temperatures, oxidation resistance, and bend transition. Of the 23 compositions tested, Cb-2OHf-5W-10Ti exhibited superior high-temperature properties. A recrystallized sample of this alloy was fabricable at room temperature, had a strength of 44,000 psi at 1,200° C, and had an oxidation rate of only 7.7 mg/cm2/hr at 1,000° C.

Jan 1, 1966

By Charles H. Fulton

One of the first matters to receive attention from the Bureau of Mines when it was authorized to undertake investigations relating to wastes in the mineral industries was the smoke problem at smelting and ore-roasting plants. This bulletin is published by the bureau primarily for persons who seek information on the subject of metallurgical smoke but are unacqllainted with the technical language of metallurgy. It is, of course, not possible to free a techniCal subject entirely from teclmicalities, but, 80 far as possible, statements are made in plain and simple English. Metallurgical smoke causes considerable friction between the metallurgical industry and agriculture in certain parts of the country. Owners of smelting plants are making every effort to devise ways and means to do away with possible damage and annoyance from smoke and are meeting with success. The problem is peculiarly difficult in this country because of the large tonnages of material that must be handled. The solution of the problem is not yet at hand and much work still remains to be done. As the mineral industry is one of the great basic industries of the country and of necessity is entitled to full consideration, it should be accorded freedom to work out the smoke problem to the benefit of all concerned. The effort is made in this paper to present the problem of metallurgical smoke as it actually exists, without bias of any kind. The writer takes this opportunity to express his indebtedness to the sources of information on which he drew, many of which are enumerated in the selected bibliography at the end of this paper. In connection with the author's use of the present tense in describing plants and methods, the reader should note that none of the references in that bibliography is of later date than 1913. Much information was obtained by personal visits and by correspondence, and thanks are hereby tendered to all persons who kindly furnished data. The writer desires to thank particularly F. G. Cottrell, chief chemist of the Bureau of Mines, for criticism and comment.

Jan 1, 1915

By H. R. Shell, Robert C. Johnson, Wilbur H. Warwick

Alpha silicon nitride fibers , Si3N4 , were successfully grown in graphite crucibles by a new method utilizing silicates and silicon ( S in equations below) as sources of silicon and using carbon , aluminum , and silicon as reducing agents (R in equations below ) . The basic reaction mechanism is believed to be generally as follows : 1,300 - 1,500 ° C S + R + N₂ SiO + RO + N₂ › 3Si0 + R + 2N₂ _1,300 - 1,500° C 3RO + Si¸N • ( 1 ) ( 2 ) A build - up of coatings on the solid raw- material particles hindered the evolution of silicon or silicon monoxide vapor and thereby slowed down further formation of silicon nitride fibers . Free oxygen in the crucible caused the formation of amorphous silicon dioxide ( SiO2 ) fibers . This problem was solved by passing , entering , and exiting gases through layers of lump graphite inside the reaction vessel . The silicon nitride fibers grew best around 1,400 ° C. Nitrogen flow rates from 4 to 6 liters per minute were adequate . The fiber widths were generally only a few microns whereas their lengths sometimes reached one - quarter inch or more . Chemical and X- ray analyses indicated that bulk fiber samples were usually 80 to 90 percent Si3N4 . The fibers had good oxidation resistance to about 1,260 ° C. Thermal shock resistance was excellent . Electrical resistance was determined .

Jan 1, 1964

By D. W. Butner

The blast -hole method for drilling and breaking ground is not new to the mining industry . For several years it has been used rather extensively in Canada , particularly in the gold mines , where it was first developed and where the major advances in the technique as applied to present - day mining problems have been made . At present , 40 mines in Canada and the United States are using the method in one form or another , and from all indications its use will increase in the future . In two California mines , blast -hole diamond drilling is now used for a part of or for all stoping operations , and in one of these it is used to some extent in development work . At the Mountain Copper Co.'s Hornet mine in Shasta County, about 50 percent of the pyritic sulfide ore produced is mined by the blast - hole method , and the U. S. Vanadium Corp. mines 80 percent of the ore produced at its Pine Creek tungsten mine in Inyo County by this method . At Pine Creek , long -hole drilling and blasting is used for mining pillars also , and in pre - stoping development . The blast -hole diamond - drilling method is not applicable to all types of ore bodies . A third property in California , the El Dorado Limestone Company , El Dorado County, tried the method for several months in 1943 and 1944 , but , owing to certain factors that greatly increased mining cost , the company soon returned to conventional mining methods .

Feb 1, 1948

By T. M. Barczak

This U.S. Bureau of Mines report investigates shield mechanics and component stress development in a two-legged longwall shield for unsymmetric canopy and base contact configurations. Previous studies analyzed shield behavior for symmetric contact configurations. The goals of these efforts are to improve longwall support selection and design. This study provides vital information that will help develop improved procedures for performance testing of longwall supports and will benefit future research to improve support design through stress optimization and evaluation of failure mechanisms. Combinations of six canopy (three symmetric and three unsymmetric) and six base (four symmetric and two unsymmetric) contacts provided a total of 36 configurations for evaluation. Of these 36 configurations, 10 were eliminated because of fixture limitations or shield instability. Controlled vertical and horizontal displacements were applied by the Bureau's mine roof simulator to the remaining 26 configurations. Component responses were determined from pressure transducer and strain gage instrumentation in order to identify contact configurations and boundary displacements that produced maximum loading in each of the support components. This report describes these test results and provides conclusions relevant to critical contact configurations for performance testing of longwall supports.

Jan 1, 1990

By James W. Myers

The Bureau of Mines studied factors affecting ignition of coal mine refuse and on methods for control of burning. Laboratory experiments showed that air permeates more readily through segregated than through nonsegregated refuse and that air permeability is greater through coarse than through fine particle refuse. Minus 3-1/4-inch refuse ignites spontaneously more readily than minus 1/4-inch refuse. The burning of a 1,000-pound conical coal pile was con-trolled by capping with an 18-inch-thick layer of minus 1/4-inch refuse containing 37 percent combustible. In field trials, the burning of refuse at operating mines was controlled by capping with a layer of fine refuse. Water, applied as a spray or by injection, quenched surface flames and cooled the burning waste. Inspection of refuse piles at operating mines showed that the spontaneous ignition tendency is affected by the exposed surface relative to the total volume and the segregation of particles during dumping.

Jan 1, 1966

By Richard D. Miller

This publication contains routine analyses and related source data for 350 natural gas samples from 19 States collected during calendar year 1362 as part of a continuous survey of the United States for occurrences of helium in natural gas. This survey has been conducted by the Helium Activity of the Bureau of Mines since 1917. The analyses published herein were made by mass spectrometer and a special helium analysis apparatus. Four previous publications have been made to present the results of 5,648 gas analyses made by the Bureau of Mines, Helium Activity, prior to 1962. The first, Bulletin 486, 3/ contains analyses and data on 2,195 gas samples collected during the period 1917-47. Bulletin 576, 4/ the second publication, includes data and analyses for 1,575 samples collected from 1947 through May 1956. The third bulletin contains 1,444 analyses and source data of samples obtained from May 1956 to January 1, 1961.

Jan 1, 1964

By W. F. Hazen

This paper describing the mining practices at a 100 per cent mechanized mine working the Pittsburgh or No. 8 coal bed in eastern Ohio is one of a series being prepared by the U. S. Bureau of Mines on mining practices, methods, and costs in the various mining districts of the United States. The purpose of assembling this data is to place before those interested in the mining industry the methods employed and the cost data on the items involved in the winning of the coal and its removal to the railroad car at the tipple. Mining costs are governed by the mining method used, which is selected for its adaptability to local natural physical conditions such as the nature and thickness of the coal, its dip, the character of the roof and floor, and the thickness of the overlying strata.

Jan 1, 1929

By W. G. Pariseau

A U.S. Bureau of Mines case study of pillar recovery in high-grade ore near the Ross shaft at the Homestake Mine, Lead, SD, has demonstrated the usefulness of the finite-element method for evaluating shaft pillar mining plans and shaft stability. This report focuses on mine measurements and calibration of the two-dimensional computer model and is the second in a series of three Reports of Investigations describing the Ross shaft study. In this study, borehole extensometers and other instruments were installed to provide data for model verification and to monitor the shaft. Results of the recalibrated two-dimensional model (UTAH2) confirmed the premining stability evaluation. However, after mining began, concern was expressed because cracks and other signs of ground motion appeared at considerable distances from the area of active pillar mining. In part 3 of the study, an intensive three-dimensional modeling effort using UTAH3 was initiated. The results again showed that the observed effects were within expectations and that the shaft would remain safe. Three-dimensional analyses of alternative pillar mining scenarios indicated that more of the shaft pillar ore reserve could be recovered than previously thought.

Jan 1, 2010

By Richard D. Miller

This publication contains routine analyses and related source data for 350 natural gas samples from 19 States collected during calendar year 1962 as part of a continuous survey of the United States for occurrences of helium in natural gas. This survey has been conducted by the Helium Activity of the Bureau of Mines since 1917. The analyses published herein were made by mass spectrometer and a special helium analysis apparatus. Four previous publications have been made to present the results of 5,648 gas analyses made by the Bureau of Mines, Helium Activity, prior to 1962. The first, Bulletin 486, 3/ contains analyses and data on 2,195 gas samples collected during the period 1917-47. Bulletin 576, 4/ the second publication, includes data and analyses for 1,575 samples collected from 1947 through May 1956. The third bulletin 5/ contains 1,444 analyses and source data of samples obtained from May 1956 to January 1, 1961.

Jan 1, 1964