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By Charles Seitz

The Bureau of Mines has modified its parts-per-billion helium-4 analyzer to improve the analytical capabilities of the instrument. The modifications resulted in the following improvements: (1) The analytical precision of the instrument for 10 consecutive analyses was improved to ±1 ppb at the 5,000-ppb helium-4 level, (2) the helium-4 sensitivity was increased almost tenfold, and (3) the minimum detectable limit for helium-4 was improved to 0.5 ppb. The modifications made to improve the instrument included replacing the ion-source control circuit with a direct-current solid-state design, controlling the temperature of the ion source, stabilizing and reducing the pumping rate of the vacuum system, and optimizing peak integration.

Jan 1, 1986

By W. W. Culter

"This paper is the outcome of thorough investigation into the value of the previous methods used for deriving production decline curves. It is highly important that methods be employed that are fundamentally sound and also practicably applicable. Six methods commonly used were studied. Some of these were found to be fundamentally in error; some save reliable curves but involved much work and time in the preparation; others gave reliable curves with less time and effort.It was found that of the methods previously employed the ""family curve"" method described in Bull. 134 Amer. Inst. Feb. 1918, pp. 499-500 by Lewis and Beal, was probably the most satisfactory. The now method given in this paper ploys the same principles as the ""family curve"" method, but is mathematical instead of graphical,The engineer and the oil man should carefully boar in mind both the use and the limitations of the average production curve such as is derived by the ""family curve"" method or other methods mentioned. Estimations of future productions or of underground oil reserves of a particular tract or well should be made from the production records of the tract or the well itself wherever such records are satisfactory. The use of the average curve of a district or field should be applied only to those properties or wells where there are not sufficient data to construct individual or tract production records, or where the productive life so short that a satisfactory individual record can not be obtained."

Jul 1, 1920

By Allen D. Look, Norman King

For many years, much thought and effort have been devoted to the achievement of safety in the use of explosives by those interested in the preservation of human life and the protection of property. As a result, we now have adequate rules pertaining to the safe use of explosives , which, if observed, would prevent many, perhaps ail , of the explosives accidents that yet occur . Although the rules respecting the use of explosives are believed to be well - known, many accidents occur because they are disregarded . The mental awareness aroused by a tragic accident usually will cause safety precautions to be taken for a while ; however , this awareness gradually disappears unless a sincere effort is made permanently to prevent similar accidents . Frequently, because safe methods are more irksome than unsafe methods , the lessons taught by accident experience are forgotten in a short time , vigilance is relaxed , and there is a gradual return to unsafe , easy methods of performing work. If the preservation of human life is important , the unfortunate experiences of others and the lessons taught by them should be applied to reduce unnecessary loss of life . The value of a life lost as the resuit of accident should be calculated not only from the monetary and humanitarian standpoint but also according to what the accident could contribute in the way of saving other lives and suffering . This saving of other lives can and will , if the lessons from unfortunate accidents are applied , convert a loss to a gain a gain of such magnitude that the accident victim could be considered

May 1, 1944

By J. B. Gayle

This investigation was conducted by the Federal Bureau of Mines to compare the selectivities of diverse flotation reagents and also of flotation and float-sink methods of separation. Flotation tests, using sodium chloride, an alcohol-type frothing agent, and a kerosine-pine oil mixture as reagents, were made on seven coking-coal samples representing four different beds. The results indicated equivalent selectivities relative to sulfur rejection when entrapment effects were minimized by recleaning the various products. Selectivities relative to ash rejection were also equivalent for some coals; for others, the selectivities of the reagents tended to increase in the order sodium chloride, alcohol-type frother, and kerosine-pine oil. Float-sink tests on these same coals generally gave results indicating better selectivities than those obtained in flotation tests at comparable levels of recovery.

Jan 1, 1960

By Daryl E. Radcliffe

The Bureau of Mines, as part of an agreement with the Bear Coal Co., Somerset, Col o., evaluated the response of a coal mine roof to time lapse. Time lapse, the interval between exposure and support of the roof, was studied using both instrumentation and statistics. Instrumentation studies were designed to equate displacement and rates of displacement with areas of roof left unsupported from 15 minutes to more than 4 days. A statistical study was completed to compare roof fall occurrence with time lapse intervals encountered during normal room-and-pillar mining. Results from this investigation show time lapse, in the Bear mine, to he insignificant with respect to roof stability after installation of permanent support.

Jan 1, 1980

By Larry R. Wilson

The development effort described herein was directed toward the design and development of a flexible communication system to provide two-way section communications between any telephone on an MCM-101 telephone FDM exchange and a miner provided with a uhf walkie-talkie transceiver. The system also provides normal communication between miners within a working section through the uhf coupler interface repeater.

Jan 1, 1976

By J. D. McLenegan

The purpose of this investigation was to prepare a market survey of the refractories industry in California and Nevada (referred to in subsequent paragraphs as the region), and to determine the degree of self-sufficiency and the potential capacity for anticipated growth. The report includes estimates of the total annual refractories consumption, the quantity of refractories imported into the region, the tonnage of raw materials required for their manufacture, and the resources of fire clay and high-alumina minerals in the region.

Jan 1, 1956

By Arnold B. Hubbard

This report describes a method of concentrating the insoluble organic material (kerogen) in a rich Colorado oil shale without any apparent alteration of its original chemical form. The method involved treating finely pulverized shale with dilute acetic acid at room temperature to remove the carbonates, which act as a cementing agent for the shale, and cause the shale particles to partly disintegrate into the organic and inorganic components. The acid-treated shale then was centrifuged in different liquid mediums ranging from 1.4 to 1.15 gravity to effect a mechanical separation. From a Colorado oil shale containing 48.0 percent ash, kerogen concentrates containing 43.3 to 8.7 percent ash were obtained. The carbon:hydrogen ratios of the kerogen in the original shale and the different concentrates were essentially the same. The oil:kerogen ratios calculated from Fischer assays of the above samples were essentially the same, regardless of the organic or inorganic contents. This was also true of the assay water:kerogen ratios of the same samples. These data indicate that no significant change occurred in the kerogen during the concentration process.

Jan 1, 1952

By Bruce D. Sartwell

A program was written which utilizes a remote teletype input to a time- sharing computer to plot charged particle or X-ray energy spectra which are stored in the memory of multichannel analyzers. The program, written in FORTRAN V, accepts the data printed out by the pulse height analyzer on paper tape and then, after reading these data tapes into the computer, plots on the teletype the desired energy spectra on a scale automatically adjusted for the maximum number occurring in the data. The program is flexible enough so that the researcher can subsequently expand or contract the vertical (intensity) or horizontal (energy) scales. With a slight modification, the program will accept data printouts from scalers or analog to digital converters. The program also includes a feature for integrating the energy peaks obtained by pulse height analysis.

Jan 1, 1970

By N. E. Hanna

An important goal in the development of coal mining explosives has been to improve their safety characteristics through suitable formulation. In the United States no systematic effort to establish factors influencing the incendivity to firedamp and to coal dust of explosives through research was made until the last decade. In consequence, American permissible explosives underwent only very slight modifications and many remained substantially the same as in the early years. As part of a long range program for increasing the safety of permissible explosives, the Bureau of Mines undertook to determine how the amounts and particle sizes of the principal constituents of these explosives affect their incendivity. It was found that an increase in the relative amount of sodium chloride and a decrease in its particle size significantly decreased the incendivity of our permissible explosives to firedamp (7-9).6 This is in agreement with findings reported by Dolan (4) for compositions of nitroglycerin and salt. One important result of the work at the Bruceton station has been the recent introduction of salt-formulated permissibles by several explosives manufacturers. This paper describes a statistically designed experiment for studying the effects of the particle size of ammonium nitrate and the type of carbonaceous materials used on the incendivity of permissible explosives. Interest in these particular effects goes back as far as the first formulations of coal mine explosives, around 1910 in the United States and even earlier in Great Britain and other countries. Although it is well established that fine

Jan 1, 1961

By E. L. Litchfield

Spark ignition of combustible-gas mixtures is a relatively old subject of investigation and has been treated both experimentally and analytically by many people. Elements of static and current electricity are almost always present in mining and industrial operations, and the spark can be an extremely efficient source of ignition. Thus the practical interest of such problems as the "intrinsic safety" of electrical apparatus is obvious. Ignition and quenching phenomena are the primary laboratory representatives of combustion phenomena that are dynamically nonsteady, and such nonsteady phenomena playa considerable part both in industrial processes and in safety matters, although they are of less immediate practical interest. Considerable effort has been expended by the Federal Bureau of Mines in investigations of spark ignition.5 6 7 8/ Primarily, this work has established the significance of several of the parameters involved. Although the

Jan 1, 1959

By H. B. Brunot

One of the many difficult problems that confront the present day coal-mine operator is the safeguarding of his employees and property from disasters such as fires, explosions, squeezes, and inundations. Those operators having gaseous or ev en dusty mines have a double responsibility resting upon them in this respect. The introduction of electrical machinery and appera tus in mining operations has been very rapid, and at the present time it is difficult to mention any kind of mining work in which electrical machinery is not used. This extended introduc- tion of electrical equipment has added not a little to the mine operators' safety problem, and it is the desire of the United States Bureau of Mines to aid the mine operator, and the inspection departments having jurisdiction, in solving their electrical safety problems. With this idea in mind, the Bureau has prepared and published schedules setting forth the qualities it considers essential to the safety of various classes of mining equipment, and the conditions under which it will test and give the stamp of its approval to satisfactory designs. Portable electric lamps of the permissible* type are almost universally used in gaseous mines, but the use of permissible electrical machinery has not been so widespread. Until recently the Bureau had issued approvals for only one class. of machinery involving the use of electric motors that is, permissible coal- cutting machines. However, the day is undoubtedly not far distant when the operator, who so desires, will be able to obtain a permissible room hoist, pump, or coal- loading outfit. During the year 1921 the first of a growing list of storage-battery locomotive approvals was granted by the Bureau, and it is with considerable satis- faction that the Bureau how announces the approval of a third class of motor equip- "merit- namely, slectric drills.

Jan 1, 1923

By R. V. Ramani, K. Bode

"IntroductionIn part 1 of this paper, the results of the experimental work in a wind tunnel under controlled conditions were presented. To understand the spatial and temporal behaviour of airborne dust under mine conditions, experiments were performed in the Lake Lynn Experimental Mine of the US Bureau of Mines. The mine airway experiments were designed to study the variations of ambient concentrations along the length of an airway, and the deposition rates and deposition velocities in an airway cross section. Other objectives of the study were to investigate the spatial and temporal behaviour of airborne dust with regard to air velocity and particle density, the size distribution of the airborne dust cloud as it travels in the airway, and the size distribution of the dust particles deposited along the airway. Other objectives of the study were to compare wind tunnel results with In-Mine results, whenever appropriate.Experimental ProcedureLocationA complete description of the Lake Lynn Laboratory Mine of the US Bureau of Mines (USBM) can be found in the US Bureau of Mines Information Circular 8911 (Mattes et al., 1983). This mine provides excellent facilities for dust experiments. The airway dimensions are similar to those of a coal mine airway. The mine has a drift (D Drift, see Figure 1) that extends almost 500 meters without interconnecting airways, stoppings, or bends. The D drift measures approximately 6m in width and 2,25m in height.The Lake Lynn Laboratory Mine· is ventilated by a variable speed, 75 kW (100 hp), 28,3 m3/s (60 000 cfm) blower fan installed on the top of the ventilation shaft. Air velocities of 1, 1,3 and 1,8 m/s, respectively, could be obtained in the D Drift. However, the temperature changes at the surface can cause small variations in air quantities and velocities underground. The low background dust level in the mine reduces the problem of sample contamination from other sources of dust. Extended periods of uninterrupted data collection can also be scheduled. Mine airway parameters which are important for the analysis include the dimensions of the airway and the ventilation data such as the air velocity, and the pressure loss in the drift. All these data were acquired during altimeter surveys which were conducted prior to each of the experiments."

Dec 1, 1995

By Oliver Bowles

Slate possesses many admirable qualities, not only as a roofing material, but for blackboards, electrical switch boards, and for various structural uses such as stair trends, floor tile, baseboards, and sanitary enclosures. The American slate industry was established manor years ago, and has made remarkable progress, particularly during the past five years. One of the chief drawbacks to more rapid expansion is the high percentage of waste which reaches 75 to 94 per cent of gross production. Much of this waste is duo to rock imperfections over which man has no control, but a careful study of tae industry by the Bureau of Mines over a period of years indicates that an undesirably large percentage of the marketable slate is wasted in the processes of quarrying and manufacture. The initial step in quarrying slate is to separate from the solid ledge masses of a size that ray be conveniently removed from the quarry. This first step entails a greater waste of material than any subsequent process, and, therefore, invites the most earnest effort toward waste reduction. Attention has consequently been directed toward possible improvements in methods of making primary cuts in the quarry floor. A study of European practice with the wire saw, together with theoretical consideration of its advantages, convinced the writer that it possessed sufficient merit to justify its use as a primary slate cutter in American quarries. No practical conclusion in this matter could be reached except by experiment. Therefore, the desirability of obtaining equipment and trying it out under actual conditions of operation was urged upon operators. While no doubt the equipment could be readily manufactured in America, it had already been developed to the point of practical use in Europe; therefore the writer urged the desirability of purchasing one completely equipped wire saw in Europe, and determining through tests whether it gave sufficient promise of success to warrant its manufacture in America.

Jan 1, 1927

By C. J. Walker

The Bureau of Mines undertook a theoretical and laboratory study to determine the feasibility of using ethylene as a tracer for natural gas in underground gas-storage reservoirs. The study indicated that ethylene was a useful gas tracer in underground gas storages. Tracer losses were not excessive. Laboratory tests were conducted at pressures as high as 500 psia in both wet and dry consolidated-sandstone cores, evaluating tracer loss with gas blends containing natural gas with different concentrations of ethylene tracer. Under certain conditions losses were less than 17 percent.

Jan 1, 1966

By H. Kenworthy

The objective of this research was to develop methods and determine conditions under which metallic sulfides with lower boiling points than sphalerite may be removed from zinc sulfide concentrates by volatilization. A higher percentage of extraction of lead, cadmium, and germanium than is common in current practice was sought. The investigation, conducted by the Metallurgical Branch of the Minerals Technology Division, Region VI, showed that, under proper conditions, it is possible to remove over 90 percent of the lead, cadmium and germanium as an enriched sublimate. The uses of lead, and cadmium to a lesser extent, are well-known. Although germanium was discovered in 1886 by C. Winkler, commercial use has been achieved only in recent years. The amount consumed per manufacturer unit is so small that the price of germanium may still be quoted by the gram. The electronic industries have been the chief consumer of this semiconductor. Germanium is sold largely to the fabricator as a dioxide for reduction to metal and subsequent processing into wafers for use in diode and triode electronic tubes. Extensive research at Purdue University during World War II led to the first practical use of germanium.

Jan 1, 1952

By C. L. Klingman

In extracting helium from natural gas at Bureau of Mines helium plants, a continuous analysis of the helium content of inlet and outlet gas streams is required to determine extraction efficiency. An analyzer, using established principles of gas chromatography to effect the analysis, has been developed by the Bureau of Mines to meet this need. It will record the helium content of inlet or discharge gases from helium-extraction plants every five minutes, continuously, without the attendance of an operator. A 25-inch column of activated charcoal is used as a partitioning agent; nitrogen is the carrier gas; and a hot-wire, thermal-conductivity cell is the detector. A 1.0 mv, strip chart indicates the unbalance of the detector cell, Sample size is 0.37 cc, and carrier gas flow rate is 75 cc, per minute. Significant improvements in helium extraction have been demonstrated by using the chromatograph in three helium-extraction plants.

Jan 1, 1961

By Deno M. Pappas

The objective of this Bureau of Mines investigation was to identlfy and evaluate alternative binder materials for use in stabilizing and consolidating highly fractured roof along longwall faces and gate roads. The desirable characteristics of a stabilization material were defined, and an extensive search was conducted to find materials satisfying these characteristics. Of 20 materials originally scrutinized, 9 were chosen for laboratory analyses. The laboratory tests evaluated bond strength and tensile strength under both dry and wet conditions. An optimum material was not found. The laboratory analyses indicated two possible candidate materials for longwall stabilization: high-aluminous cement and two-component epoxy; however, the tensile strength of the high-aluminous cement was mediocre, and the epoxy cement is toxic, flammable, and fairly expensive. The potential market demand for an effective and economical stabilization macerial is discussed in the appendix.

Jan 1, 1988

By Byron M. Bird

"The prevailing practice of washing unsized coal, 1/2-inch and finer, to 1/8-inch and finer, on a table is subject to certain limitations which are commonly overlooked. In some instances good results are obtained by this method, but often the opposite is true and the efficiency of the washing operation is low. Although the separation taking place on a concentrating table is not fully understood, the actual distribution of particles of various sizes and specific gravities was determined a number of years ago by ore-dressing investigators. Hence this paper consists of an analysis of an old problem by new methods. The experimental data on which the discussion is based were obtained in the course of coal-washing investigations conducted by the U. S. Bureau of Mines at the Northwest Experiment Station in cooperation with the University of Washington and with certain coal operator: of that State.Experimental WorkThe general method of study has been to take a large number of zonal products from the table, and separate them according to specific gravity and size into their component parts. The table used is one of the standard commercial sizes with a diagonal deck. The coal to be washed is split into representative portions, which are stored in separate bins. One portion is used for ""timing as"" the table; the products are collected continuously in the same turned to the feed bin, and thus a closed circuit is completed. When the despite conditions on the table are obtained, coal is fed from one of the re. After the table is operating smoothly the entire product is minute; such a sample is sufficiently large to represent accurately the work of the table and at the same time to minimize the effect of beginning at the end next to the head motion, separate samples are made for each foot along the edge of the deck."

Jun 1, 1926

By Martin H. Stanezyk

The Bureau of Mines investigated leaching of selected copper sulfide minerals and a composite of impure flotation concentrates at elevated temperatures and pressures with ammoniacal solutions. Copper 1 (tractions of 96 percent were obtained by leaching chalcopyrite at 75° C under oxidizing conditions for 60 minutes. An extraction of 99 percent of the copper contained in the composite concentrate was obtained by leaching the product for 90 minutes at 75° C. In tests of bornite, chalcocite, and covellite, 90 to 97 percent of the copper was extracted at 20° C provided an 8-hour reaction period was used. At 75° C essentially complete dissolution of the copper from these three minerals was accomplished in 60 minutes. Additions of ammonium sulfate to the leach solutions were required to obtain high-percentage extractions of the copper from bornite, chalcocite, and covellite. Although ammonium sulfate was not required when digesting chalcopyrite, copper extraction was enhanced and less free ammonia was required when ammonium sulfate was added to the leach pulps. The chemistry of leaching copper minerals was studied. It was C, termined that chalcocite altered to covellite as one step in the dissolution When leaching iron-bearing copper sulfides, hydrated iron oxide formed on the mineral surfaces, indicating that a diffusion process prevailed. No evidence of covellite was detected.

Jan 1, 1966