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By D. E. Emerson, C. G. Kirkland, E. M. Frost

An apparatus has been developed for determining the helium content of gases containing 40 percent or more helium . It utilizes activated coconut charcoal at liquid nitrogen temperatures to adsorb constituents other than helium in the mixture . Series of analyses have been run where the mean deviation was less than 0.05 percent helium . Twenty or more analyses can be made in an 8- hour day .

Jan 1, 1964

By D. B. Dow

"Natural gas-gasoline is made by collecting in the liquid state the condensable hydrocarbon vapors that exist in different natural gases in varying amounts. In the richer type of natural gas the gasoline is generally recovered by compression and cooling. If exceedingly high pressure or low temperature is used, there is dissolved in the gasoline a large amount of very volatile material, which evaporates rapidly at atmospheric temperature and pressure.In the leaner type of natural gas, the gasoline vapors are selectively absorbed from the permanent gases by passing the natural gas through an absorbing oil. The gasoline is recovered by distilling the saturated oil, and as compared with ""compression"" gasoline is of high Baume' gravity and low vapor pressure. Before a volatile gasoline can be transported in tank cars, it is necessary to decrease its volatility in order to lessen the risk of fire or explosion, as well as to prevent excessive evaporation in transit. This can be accomplished either by weathering the gasoline, or by blending it with a more stable material, naphtha being commonly used in the weathering process the more volatile portions of the gasoline are allowed to evaporate and the losses in volume are very large, therefore, blending is preferable, wherever possible.It is very difficult, however, to produce by blending, in gasoline plants, a motor fuel which is equal to straight-run refinery gasoline. In order to make a blended motor fuel of a grade equal to straight-run gasoline, only a small percentage of natural gas-gasoline can be blended with the naphtha, consequently it is customary to blend the gasoline with only enough naphtha to enable It to be shipped to an oil refinery when the material is again blended to form a finished motor fuel."

Sep 1, 1921

By K. O. Bennington

The thermodynamic properties of synthetic acmite, NaFe3+Si206, were determined by the Bureau of Mines. The enthalpy of formation was determined by hydrofluoric acid solution calorimetry. The values of the standard enthalpy of formation at 298.15 K, ?Hf°298.15, from the elements and from the oxides, ?H°298.15, are ?Hf°298.15 = -615.87 ±0.71 kcal/mole, ?H°298.15 (from oxides) = -32.08 ±0.53 kcal/mole. Various experimental data were combined with other data from the literature to calculate all the related thermodynamic properties in the range of 298 to 1,263 K. The standard Gibbs energy of formation is ?Gf°298.15 = -575.8 kcal/mole.

Jan 1, 1981

By E. G. King

Difficulty has been encountered in making thermodynamic calculations of metallurgical reactions involving interoxidic compounds of the ferroalloy elements because of the serious lack of most thermodynamic data for these substances. This Bureau of Mines report (the first of a planned series dealing with entropies of vanadates, tungstates, and molybdates) presents low-temperature heat-capacity data and entropy values at 298.15° K. for three crystalline sodium vanadates--metavanadate (NaV03), orthovanadate (Na3VO4), and pyro-vanadate (Na4V2O7). The results are combined with data for the constituent oxides and elements to obtain entropies of formation of the vanadates. Previous to this report only one vanadate had been studied Similarly, ammonium metavanadate.4/

Jan 1, 1961

By J. L. Ambs

The U.S. Bureau of Mines (USBM) Diesel Research Program emphasizes the development and evaluation of emission control devices to reduce exposure of miners to diesel exhaust pollutants. Studies by the USBM have shown that diesel exhaust aerosol (DEA) contributes a substantial portion of the respirable aerosol in underground coal mines using diesel equipment not equipped with emission controls. The USBM and the Donaldson Co., Inc., Minneapolis, MN, have developed a low-temperature, disposable diesel exhaust filter (DDEF) for use on permissible diesel haulage vehicles equipped with waterbath exhaust conditioners. These were evaluated in three underground, mines, to determine their effectiveness in reducing DEA concentrations. The DDEF reduced DEA concentrations from 70 to 90 pct at these mines. The usable life of the filter ranged from 10 to 32 h, depending on factors that affect DEA output, such 'as mine altitude, engine type, and duty-cycle. Cost per filter is approximately $40.

Jan 1, 2010

By James P. Bennett

In this Bureau of Mines study, portions of four acidproof bricks (two red shale and two fireclay) were exposed to 20 wt pct RCI at 900 C for periods of 30 days. Three different techniques were selected to deter-mine volume expansion of these materials after exposure. Linear expansions ranging from about 0.02 to 0.12 pct were noted from Ta pin and dilatometer measurements. The use of strain gages to measure expansions was not successful. The red shale and fireclay brick with the lowest apparent porosities had the lowest expansions. Expansion data obtained by direct measurement of samples exposed for 30-day periods or by dilatometric measurement of autoclaved samples ex-posed for 2 h were comparable. This suggests the use of an accelerated autoclave exposure procedure for determining volume expansion effects of ceramic materials in acid environments.

Jan 1, 1985

By G. R. Hopkins

The petroleum-refining industry established a new record in fuel efficiency at refineries in 1936, when 597,000 B. t. u. of heat were required to refine a barrel of crude oil, compared with an average of 615,000 B. t. u. in 1935 (see fig. 1). The principal factor in the "indicated gain in fuel efficiency at refineries in 1936 was an increase in crude runs of 11 percent over 1935. A large part of the heat utilized at refineries is consumed elsewhere than under stills, or in ways quite independent of crude-oil distillation. In other words, as the operating ratio (crude runs divided by capacity) for refineries increases toward the maximum of 100 percent, the fuel requirements show progressively smaller increases and the average E. t. u. consumption per barrel of crude refined declines.

Jan 1, 1938

By Vernon F. Swanson

Several laboratory flotation tests were conducted by the Bureau of Mines on a sample of unweathered diorite from the B. F. Camden property, Amherst County, Va. Results showed that an ilmenite concentrate analyzing 45.5 percent Ti02 (titania), 0.07 percent P205 (phosphorus pentoxide), and 2.21 percent Si02 (silicon dioxide) could be produced from a feed containing 7.72 percent Ti02 and 3.94 percent P205. Ti02 recovery in the concentrate was 47.6 percent in a batch test. The weathered saprolite material overlying the diorite required scrubbing and desliming to remove argillaceous material and preliminary flotation of apatite followed by flotation of ilmenite. The resulting concentrate analyzed 47.3 percent Ti02, 0.19 percent P205, and 0.99 percent Si02 from a starting feed of 8.99 percent Ti02 and 3.37 percent P205; TiO2 recovery was 54.5 percent.

Jan 1, 1963

By E. P. Youngman

A new mining law for the Recublic of Polend was promulgated by presiden- tial decree dated November 29, 1930, published in the Journal of Lews (Dzienni stex) No. E, text 654, December E, 1530, and wes to become effective January 1, 1932, in all Polend except Silesie. Its adoption in Silesia wes dependent pon the action of the Silesian Diet. As the new law is considered an im- provement over the old Austrian Mining Lew, which is operative in the Silesian districts of Bielsk and Cieszyn, and the Prussian Kining Law, which is opera- tive in Upper Silesia, no delay in its adoption for Silesin was looked for. This new law codifies the various juridical regulations pertaining to ines existing in different parts of the Polish Republic but does not include legislation with respect to the extraction of minerel oil, especially crude oil. Petroleum legislation was postponed to a later date in order to facili- tate codification in other fields. Koreover, as the oil industry exists in Galicia elone, deley will not be detrimental.

May 1, 1932

By A. L. Engel

A representative sample of gold-silver ore from the Keystone Mine, Manhattan, Nye County, Nev., was submitted for these tests. The ore was an altered diorite rock with very small amounts of sulfide minerals of copper, lead, zinc, antimony, and arsenic disseminated in fine grains throughout. As indicated by test results, much of the silver content of the ore apparently was associated with these sulfide minerals. The gold probably occurred with iron oxides in the ore. Assays showed 0.16 ounce of gold and 2.8 ounces of silver per ton of ore. This investigation was made to study application of activated carbon in the cyanidation treatment of the ore. The treatment proposed for u.se at the mill is as follows: The ore is crushed to minus-10-mesh size and separated into plus -and minus-65-mesh portions. The minus-10, plus 65-mesh sands are cyanided by leaching and the minus -65-mesh slimes by agitating. After 48 hours of agitation the slime pulp is thickened to about 1:1 water:solid ratio, and part of the pregnant solution is recovered. The pulp is then diluted to a 2:1 ratio, and the remaining dissolved values are extracted with the activated carbon. The barren pulp then can be discarded. This procedure eliminates the necessity for further washing the slime pulp and also recovers most of the excess sodium cyanide required for extracting the optimum amount of silver from this portion of the ore.

Jan 1, 1951

By K. E. Tame

As part of a Bureau of Mines survey of radioactive waste disposal , a laboratory investigation was made to study such problems in carbonate leaching mills . Because uranium concentrators employing carbonate leaching with caustic precipitation normally recycle barren solutions to the washing circuit , the disposal of liquid radioactive wastes is automatically controlled . However , it was deemed important to determine the actual radium 226 concentrations occurring in this type of milling so that the survey of the entire industry would be complete . The laboratory procedure consisted of leaching the ground ore at 85 ° to 90 ° C and 50 pct solids for 6 hours in a sodium carbonate - sodium bicarbonate solution . The pulp was filtered to obtain a pregnant solution that was reacted with sodium hydroxide to precipitate the uranium as sodium diuranate . Regeneration of the barren solution was accomplished by gassing with carbon dioxide . The solution then was reused by advancing the solution through the washing to the leaching operations . The radioactivity in the pregnant solution was unusually high , averaging 6,500 disintegrations per minute ( dpm ) of radium 226 per liter . However , over 95 pct of the radium was precipitated with the uranium . Consequently , no buildup of radium occurred upon reuse of the barren solutions for washing .

Jan 1, 1964

By K. K. Kelley, W. W. Weller

Heat capacity measurements of akermanite ( Ca,MgSiO ) , cordierite (Mg2A14 Sig018 ) , gehlenite ( Ca₂Al₂ SiO ) , and merwinite ( Ca ,MgSiO ) were conducted over the temperature range from 50 ° to 298.15 ° K. The entropies at 298.15 K ( expressed in cal / deg mole ) were evaluated as follows : Akermanite , 50.0 ± 0.5 ; cordierite , 97.3 ± 0.9 ; gehlenite , 47.4 ± 0.4 ; and merwinite , 60.5 ± 0.5 . All four compounds have positive entropies of formation from their constituent oxides at 298.15 ° K ; the values range from 4.6 cal /deg mole for akermanite to 10.1 cal / deg mole for cordierite .

Jan 1, 1963

By H. B. Humphrey, F. E. Cash

The Birmingham coal-mining district of Alabama has many local physical conditions that contribute largely to the proble of preventing coalmine fatalities . Coal : nes of Alabama have been under the supervision of the State mine inspector since 1892 , and reports have been made with increasing completeness since that time . The U. S. Bureau of Mines has maintained a station of the safety division in the district since 1912 to cooperate with operators and the State in the advancement of safety in mining . A description of conditions in regard to fatal accidents as they have been and as they now are in Alabama , compared with the entire United States , will indicate the progress that has been made and that should still be made in reducing fatal mine accidents .

Sep 1, 1930

By Guy E. Dent, Robert S. Sandford, W. T. Millar, Hugo E. Kuehn

"INTRODUCTION AND SUMMARYDuring the latter part of 1943 a magnetometric survey was conducted by the Geophysical Division of the Bureau of Mines at the mine, Putnam County, N. Y., in an endeavor to locate a segment of the body that reports state was cut off by a fault. The Mahepac mine was abandoned about 1895 after producing nearly 1,000,000 tons of high-grade magetite iron ore. The results of the investigation indicate the termination of the ore body by ""pinching"" or a displacement of such magnitude as to place any extension at a considerable distance the original ore body. This report describes the work done on the project and presents the data obtained. ACKNOWLEDGMENTSThe Bureau of Mines has been investigating deposits of critical and essential minerals in the United States and Alaska since 1939. The Mahopac mine was visited by W.T. Millar, an engineer of the Bureau of Mines, on June 5, 1943, accompanied by Dr. William Agar of the Federal Survey, and again on July 29, 1943, accompanied by Dr. A. F. Buddington and H.F. Hawkes, both of the Geological Survey.The mineral investigation was under the general supervision of Paul M. Tyler, formerly regional engineer, Eastern Region; J. D. Bardill, formerly district engineer; and Dr. F.W. Lee, formerly chief. Division, Geophysical Exploration. The work was done under the immediate supervision of W. T. Millar, project engineer. The Geophysical Survey was made by Hugo Kuehn and Guy E. Dent."

Sep 1, 1948

By Jeffery L. Kohler, Eric R. Bauer

Prolonged exposure to noise over a period of years generally causes permanent damage to the auditory nerve and/or its sensory components. This irreversible damage, known as noise-induced hearing loss (NIHL), is the most common occupational disease in the United States today. Workers suffering from NIHL have difficulty understanding human speech and hearing other workplace cues. Despite the use of regulations and efforts by government and industry to reduce NIHL, the problem today is as prevalent as it was more - than two decades ago. Recently, the Mine Safety and Health Administration (MSHA) promulgated a new regulation that is designed to reduce NIHL in the mining industry. One of the more significant provisions is the elimination of MSHA's past practice of giving "credit" for the use of personal hearing protection, thereby reestablishing the primacy of engineering and administrative controls. However, there is a knowledge gap that is impeding the development and implementation of engineering and administrative controls. Although significant data exist on the exposure to noise by occupational code, little is known about the noise sources that contribute the most to the worker's dose. This is problematic in a workplace with multiple noise sources and workers who travel among noise sources. Yet without this knowledge, it is difficult to focus control efforts in any practical manner. Thus, it is important to characterize noise sources sufficiently well so that the sources most hazardous to hearing are identified and those conditions of exposure that are most amenable to engineering controls are pinpointed as well. The Pittsburgh Research Laboratory (PRL) of the National Institute for Occupational Safety and Health (NIOSH) is conducting a cross-sectional survey of noise sources and worker noise exposures in the mining industry to address this deficiency. The initial effort, conducted at a coal preparation plant and results are described in this paper. Preliminary analyses indicate that the noise levels on all floors exceeds 90 dBA in most areas, and that levels as high as 115 dBA were recorded. In addition, the one worker whose responsibility is to monitor the equipment and "house clean" the plant is slightly overexposed, even though he spends only half the shift in the plant. General information on the hearing loss problem in mining, a review of hearing protection use and noise regulations in mining, and other background materials are also presented.

By R. T. DeWoody, W. C. Miller, W. Chester

Studies were made to determine the effect of the shape of a pneumaticrock- drill exhaust muffler on its efficiency, and the origin and reduction of exit noise from the mufflers. Tests of mufflers of three different shapes proved that the shape is not critical and that a muffler could be incorporated into the shell of the drill. Petal diffusers are beneficial in reducing exit noise but add another projection to the machine. Increasing the number of exit openings while maintaining the same area of exit opening has a markedly beneficial effect on the exit noise and appears to be the most satisfactory treatment.

Jan 1, 1964

By John A. Breslin

Size distributions and concentrations of particulates emitted from diesel engine exhausts were measured with cascade impactors. Samples were taken from the exhaust of two types of engines using three types of fuel and operating under five different engine speed and load conditions. The measured mass median diameters of the diesel particulates were typically about 0.3 um. There was no significant difference in mass median diameter between engines or fuels and only a slight dependence on operating mode. Concentration measurements ranged from 14.2 to 250.9 mg/cu m, and calculated mass outputs, from 64 to 10,000 mg/min. Significant differences in mass output were found between engines, fuels, and especially between different operating modes. The quantity of clean dilution air that would be required to reduce the particulate mass concentration below the 2.0 mg/cu m respirable dust standard for coal mines was greater than the dilution air required to meet the standards for noxious gases for both engines tested.

Jan 1, 1976

By W. W. Weller

Heat capacities of ferrous molybdate (FeMoO4) and ferrous tungstate (FeWO4) were measured over the temperature range 51° to 298.15° K. Ferrous tungstate has a lambda type heat capacity anomaly at 74° K. The 298.15° K entropies are FeMoO4) 30.9 cal/deg mole and FeW04) 31.5 cal/deg mole.

Jan 1, 1966

By E. S. Leaver

The mineral value in the ores from the Mother Lode mining districts of California is almost entirely gold, Although many mines have produced extremely high-grade ore the usual mill grade averages approximately $7.00 gold per ton. Fully 80 per cent of the gold has been and is now being recovered by amalgamation. Various methods have been introduced to recover the gold that was not obtained by the amalgamation processes. They include vari¬ous kinds of gravity concentration which in some cases were followed by chlorination or cyanidation. The usual practice includes only stamp battery, plate-amalgamation, and vanner concentration. In the very early practice the tails were run to waste through the main drainage streams of the different mining districts. During later years very large storage dumps have been impounded. These old tails, together with those being saved from present mills, furnish the problem discussed in this article. The clean sand portion of these mill tails is amenable to the usual cyanidation. The slime portion contains the major amount of the gold lost, but it also contains 1-1/2 to 3 per cent carbon, which precludes direct cyanidation of this part of these low-grade waste tails. The black carbonaceous slime portion is the particular problem considered in this report.

Jan 1, 1930

By K. K. Kelley, W. W. Weller

This report contains experimentally determined heat capacity data for four crystalline sulfides -- AsS , GeS , NiS , and Ni3 S₂ -- over the temperature range from 50 ° to 298.15 ° K. The heat capacity data were used to evaluate the entropies of the sulfides at 298.15 ° K. Entropies of formation from the metals and rhombic sulfur and from the metals and diatomic sulfur gas are also included .

Jan 1, 1964