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By John R. Hoskins

Uniaxial compressive strength of rock is usually determined in the laboratory from cylindrical samples that vary in diameter from 5/8 to 8 inches, using a spherically seated compression head of unspecified size. The Bureau of Mines conducted a series of tests on limestone, marble, sand-stone, granite, and plaster of paris to determine the influence of the spherical head sizes and the specimen diameters themselves on the uniaxial compressive strength. Cylindrical samples of several different diameters of each rock type, all having a length of twice their diameter, were prepared and broken using at least three different diameter spherical heads. Analysis of the data shows that spherical head size does not significantly affect the uniaxial compressive strength of cylindrical rock samples. However, the diameter of the rock specimens does significantly affect the uniaxial compressive strength. Within the range of specimen diameters tested, a coefficient of variation of 6.4 percent for plaster of paris can be attributed to the selection of specimen diameter alone. Similarly, a maximum coefficient of variation of 4.7 percent for the rock types tested can be attributed to the specimen diameter alone.

Jan 1, 1969

By R. J. Leary

The natural gas-air burner described in this report was designed and constructed to meet the thermal requirements of a convective process for heating steel scrap. This process involved downward combustion of natural gas with air, blending the combustion products with diluent air, and then passing this tempered stream of gases downward through a porous bed of steel scrap contained in the furnace chamber. The scrap would be heated to a temperature limited by the adiabatic flame temperature of the gas stream in a period that depended on the rate at which heat was supplied per unit of bed cross section. The temperature of the gas stream would be limited to that beyond which an objectionable degree of oxidation would occur; for carbon steel this limit had been found to vary from 1,900° to 2,100° F. with the superficial velocity of the gas stream. The productivity of the process was dependent on the rate of heat input per unit of furnace cross section; for the 3-foot-diameter experimental furnace an input of 680,000 B.t.u. per hour was desired. The burner described was designed to meet these conditions of temperature and heat input. It provided for three streams of entering gases: (1) A primary air-fuel mixture too rich to be combustible, that is, above the upper flammable limit; (2) secondary air for combustion of the primary mixture; and (3) tertiary air, principally for cooling the combustion products to the temperatures desired for process operation. Downward combustion of the primary and secondary streams occurred in a flame stabilized on an annular port, while tertiary air flowed in an annular path surrounding the port and also through an axial channel whose wall formed the inner ring of the annular port. This burner performed beyond the designed heat-input rates while producing stable flames, which were adjusted readily to the temperatures desired. Gas-stream temperatures were easily controlled to within 15° F. of the desired value by simple manual adjustment of the flow valves.

Jan 1, 1959

By H. W. St. Clair

This study of the rate of evaporation of zinc was undertaken as a part, of a general investigation on refining mixtures of metals resulting from melting reclaimed scrap. One of the methods by which the more volatile metals, such as zinc, magnesium, and cadmium, may be separated is by distillation. Distillation may be carried out at lower temperatures if it is done in an evacuated enclosure. The immediate purpose of the present investigation was to determine accurately the effect of temperature, pressure, and other factors on the rate of evaporation of zinc.

Jan 1, 1950

By Israel Liebman

The Bureau of Mines developed three types of passive water barriers for suppressing slow-moving coal dust explosions. One type is a modification of a conventional tub barrier and depends on the dynamic pressure generated ahead of an explosion to tilt the tub to release its water and suppress the explosion. The other two barriers operate in response to an increase in static pressure developed ahead of the explosion. Tests indicate the first barrier begins to release its water at air speeds as low as 50 ft/sec, and the second and third barriers will operate at a rise in static pressure as little as 0.5 psi. All three barriers were found to be effective in suppressing coal dust explosions propagating at speeds as low as 100 ft/sec. A plan is described for installing a water barrier in a working mine on a trial basis.

Jan 1, 1976

By W. Miola, R. V. Ramaoi

"The MSHA prescribed method for the determination of quartz in airborne respirable-dust samples from underground coal mines is the P-7 method, a combination of /ow-temperature, radio-frequency ashing (LTA) and infra7 red analysis (IR). There is no prescribed procedure for quartz analysis in bulk samples of coal and host rock. Dispersive infrared (IR), Fourier-transform infrared (FTIR) and X-ray diffraction (XRD) methods are most commonly used for the analysis of quartz in powders. Several aspects of the experimental procedures, such as the preparation of the analysis sample from bulk samples, ashing techniques, scanning procedures, peak measurement location, calibration techniques, sample amounts, size consist and data interpretation, affect the results from each of the methods differently. Significant differences in analytical results obtained from X-ray diffraction (XRD) and infrared spectroscopy (IR) on the same samples are reported. All studies point to the need for reliable quartz analysis methods.In a recent research program, a procedure for preparing bulk-coal and host-rock samples for quantitative quartz analysis was developed. Further, the results from X-ray diffractometry and infrared spectroscopy for quartz content on identical samples were compared. Calibrations with pure and mixed standards were used to assess the influence of particle-size distribution, matrix and calibration on the analytical results. In this paper, several issues concerning the measurement of quartz in the samples of coal, host-rock and airborne respirable dust from mines are outlined and quantified. IntroductionThe literature on coal-mine airborne-dust control has identified a need for a better understanding of the sources, mechanisms and amounts of quartz in mine airborne respirable dust (Althouse, 1984; Jankowski, Nesbit and Kissel, 1985; Ramani 1988; Qin, 1988; Bhaskar and Xu, 1990; Bhaskar and Li, 1992; Ramani, Qin and Miola, 1991 ). To understand the quartz content in the source materials, bulk samples of coal and host rock must be analyzed. Establishing an analysis procedure for determining the quartz content in bulk-coal and host-rock samples is necessary for identifying the sources of quartz in mines; for establishing the relationships between the quartz contained in the source and in the airborne dust; and for controlling the content of quartz in the mined product and in the airborne respirable dust."

Dec 1, 1996

By D. A. Reynolds

Yields of ammonium sulfate obtained in the carbonization of coal frequently vary from plant to plant, because ammonia is an unstable compound at high temperatures and therefore sensitive, to changes in carbonizing conditions. Differences in byproduct yields of ammonium sulfate obtained at different plants generally are accounted for by variations in plant procedure, either in preparing the coal or in its carbonization. However, technicians of one large corporation,- which frequently obtained higher yields of ammonium sulfate in its Alabama plants than ever were attained in its Ohio plants, "could not reconcile the differences in yields with their plant operations. These investigators suspected that the Alabama, coal used in their southern plant yielded more ammonia because its composition differed inherently from that of the Pennsylvania and West Virginia coals fused in their Ohio plants, although this concept could not be proved readily in their large-scale operations. Their view is supported by experimental data obtained A Beau of Mines-American Gas Association (BM-AGA) carbonization tests) -21 of a large number of coals including those carbonized commercially in Alabama and Ohio.

Jan 1, 1949

By Sumner M. Anderson

THE importance of the mineral industries of the Latin American area in 1964 may be evaluated in respect to a number of points of reference, a few of which are measurable and appropriate for examination. With regard to the region's contribution to total world production, it accounted for total 1964 world output of natural nitrates (from Chile), and about 97 percent of the optical and electrical grades of quartz crystal (from Brazil). The region supplied over 20 percent of world output of 7 other mineral commodities and accounted for 4 percent or more of world output of 19 other mineral products. Among major commodities, the area, occupying 15 percent of the earth's land surface, supplied within 3 percent of that proportion of the world's output of copper, lead, tin, zinc, barite, and crude petroleum. Incomplete compilation of production data, particularly that of nonmetallic minerals, precludes production estimates on some items for the area ass whole, and therefore the importance of Latin America as a world producer of some additional commodities may not be clearly assessed. For example, most of the countries of the area collect only incomplete data or no data at all on the production of clays and other ceramic materials, sand and gravel, dimension and crushed stone, lime, ornamental and precious stones, perlite, vermiculite, carbon black, coal tar products, and petrochemicals. In the case of many countries of the area, the value of production of one or more of these commodities greatly exceeded that of other mineral industry products that are carefully reported.

Jan 1, 1966

Early in 1936 the Interstate Oil Compact Commission and other groups interested in forecasts of demand for petroleum requested the Bureau of Mines to make a physical inventory of crude-oil stocks in the United States. Accordingly, the 74th Congress -appropriated funds for conducting such a survey during the fiscal year ended June 30, 1937. In the discussions end hearings2/ relative to the need for the survey, the opinion was expressed that crude oil held is storage for long periods had lost so much of its gasoline content that the economic significance of total stocks should be discounted materially. Therefore, a primary objective of the survey was to

Jan 1, 1938

By David Burgess

Natural gas is a general term applied to the gas obtained from oil or gas wells. It is the most widely used of all gaseous fuels. The principal disadvantage in the use of this and other gaseous fuels is the difficulty encountered in the storage and transportation of large quantities in the gas state. Handling in the liquid state is possible, but reduced temperatures are required since methane (table 1) is the principal component of most natural gases that are used as fuels. Actually, liquid storage has been utilized both here and abroad;3 however, the Cleveland disaster4 has pointed out the need for a critical evaluation of the hazards involved in the storage of this cryogenic fuel. Accordingly, a program was undertaken to obtain basic data that could be used to assess these hazards. In this report, the factors to be considered in an evaluation of the fire and explosion hazards associated with any fuel are each discussed briefly. These factors are then used to assist in the design of experiments for the evaluation of the hazards associated with liquefied natural gas (LNG) relative to those associated with other common fuels. Experiments have been conducted on the vaporization of LNG, the mixing of LNG vapors with air, the effect of temperature and nitrogen dilution on the limits of flammability of methane in air, the burning rates of LNG and other fuels, flame radiation, and extinguishment of fires above liquid pools. Based on the results of these experiments, LNG can be stored safely in suitably designed above-ground tanks surrounded by earthen dikes in much the same manner as gasoline.

Jan 1, 1962

By W. P. Yant

Canister-type gas masks Pave become an essential part of the equipment of many industries, not only for use in .emergencies, but also in performing normal operations of industrial processes and procedures, particularly where ventilation is not practically or economically feasible. They are also used widely for enhancing safety of operations which previous to the development of gas masks had been performed in harmful atmospheres. Since the inception of industrial gas masks the Bureau of Mines has been actively engaged in endeavoring to increase the efficiency and safety of these devices, and this bureau bas become a source of advice to manufacturers in producing devices of good quality and to industry in the proper selection and use of these devices. In order to give first-hand information and keep current with the demands and needs of industry it is necessary to perform investigations from time to time. This report deals with tests of certain types of commercial gas-mask canisters for protection against mercury vapor.

Jan 1, 1932

By Dale William Avery

Thirty mines and prospects were studied; 22 are within the Dolus Lakes RARE II area. Three properties within the area and one adjacent to it were determined to have indicated or inferred gold, silver, or molybdenum resources (fig. 1 and table 1) associated with quartz veins and shear zones or quartz-pyrite stockworks in granodiorite. Five other properties in the area and three just outside have potential for the discovery of gold and silver resources. Minor amounts of very fine-grained placer gold are in glacial outwash in and near the area. The John G. Carlisle Mine (fig. 1, no. 9) produced 120 oz (3.7 kg) of gold between 1897-1899. The Independence Mine produced 481 oz (15 kg) gold, 197 oz (6.1 kg) silver, and 189 lb (86 kg) of copper between 1926 and 1935. These mines are adjacent to the study area's northern boundary.

Jan 1, 1983

By M. D. Schlesinger

As part of the development of processes for producing synthetic fuels from coal, the Bureau of Mines prepared a special jet fuel in a pilot plant for evaluation by the Air Force. This jet fuel had all the required physical properties, including the important specifications of high heating value and high density. However, the finished fuel did not pass the stability test specified by the Air Force and conducted by the Southwest Research Institute in a high-temperature research coker. The cause for this instability is being investigated because pure compounds of the type identified in this fuel are known to be stable. The tar acid oil used was a 230° to 300° C. fraction of low-temperature tar obtained by carbonization of a West Virginia bituminous coal in the pilot plant of the Consolidation Coal Co. Both the desulfurization at 400° C. and saturation at 300" C. were done in the vapor phase at 2,500 p.s.i.g. After catalytic treatment and distillation the final jet fuel had a boiling range of 194° to 247° C., a net heating value of 18,420 B.t.u./lb. and a specific gravity of 0.8463 60° F./60° F. It also had u pour point below -62° C., and at 0° C. its viscosity was 4.5 cs. The oil was virtually all bicyclic, 41 pct. noncondensed and 56 pct. condensed.

Jan 1, 1961

By F. X. Tartaron

This report describes work done by the Bureau of Mines to simplify the design and operation of the vortex cone, a new device for prerefining blast furnace iron. Three new apparatus arrangements were tested. Results with one of these arrangements average 74.2 pct silicon removal and 61 pet oxygen efficiency (disregarding removal of carbon and manganese).

Jan 1, 1965

By D. Harrington, W. J. Fene

That fatalities from mine explosions can be very much reduced from the experience of past years if not wholly eliminated was fairly well demonstrated during the fiscal year ended June 30 , 1934 , there being only 28 deaths in the United States from explosions during this period . This is by far the lowest number of fatalities from explosions in the history of coal mining in the United States insofar as records are available . Although the frequency of occurrence of explosions has not decreased greatly during the past 6 years , there has been a marked decrease in severity , indicating that our coal -mining people are taking more effective precautions to prevent the spread of explosions . Pennsylvania is a good example of what may be done in reducing both the frequency and the severity of explosions ; by the adoption of up- to - date safety measures , Pennsylvania bituminous mines now have the enviable record of only one major explosion disaster in more than 5 years , and the one major explosion which did occur cost but 7 lives although 277 persons were exposed ; their lives were saved because rock- dusting prevented the spread of the flame and violence . Many of our other mining States are making definite progress in working mines without disastrous explosions and fires ; some of these , like Alabama , West Virginia , Indiana , Wyoming, and others now operating with few , if any , explosions , have had anything but a favorable record in the past .

Jan 1, 1935

By Bruce I. Thomas

Reconnaissance studies of beach sands along the eastern part of the Gulf of Alaska were conducted by the Bureau of Mines to determine if any of these coastal areas warranted investigations as possible sources of valuable minerals. Because of difficult access and limited transportation facilities only a minimum of sampling, surveying, and camping equipment is utilized to obtain spot samples from key areas as well as information indicating the location, size, and character of the deposits. Such data were obtained from beaches located along approximately 247 miles of the Gulf of Alaska coastline during parts of the 1957 and 1958 field seasons. A total of 201 3-inch-diameter auger holes, spaced roughly at 1 mile intervals, were bored by hand methods to depths ranging from 3 feet to 27 feet; also 33 shovel samples were collected from selected localities. Samples were reduced to a rough concentrate in the field by panning; the rough concentrates were shipped to the Bureau of Mines laboratory at Juneau for further concentration and for petrographic and chemical analyses. Particular attention was given to the heavy-mineral content of the concentrates, although the types and relative amounts of rock-forming minerals were also determined. The reconnaissance indicated that, generally, the valuable mineral content of the beach deposits was too low to be of further interest except in the vicinity of Yakutat and Lituya Bays where erratic but possibly significant concentrations of magnetite and/or ilmenite were found. At Yakutat, about 20 miles of beachline extending southeasterly from Ocean Cape, yielded samplas containing from 1 pound to over 300 pounds of iron and from a trace to over 100 pounds of titanium dioxide (TiO2) per cubic yard of beach material. However, the higher grade samples represented local concentrations of minor importance. The general tenor of the Yakutat beach, as indicated by the airthmetical average of 27 auger-hole samples, is about 35 pounds of iron and 20.5 pounds of titanium dioxide per cubic yard of beach material. Ilmenite is the predominant heavy mineral of the beach deposits in the vicinity of Lituya Bay, but it was found in concentrations only in limited areas near the

Jan 1, 1962

By John P. Powell

The increasing demands for petroleum and its products and the steadily increasing cost of discovering and developing new oil fields are factors that emphasize the importance of increasing the recovery of oil from known petroleum reserves. Water flooding is a valuable conservation measure, not only preventing premature abandonment of stripper leases but also reviving interest in many areas previously abandoned. The use of water flooding as a means for recovering additional oil from partly depleted oil-bearing formations was first tried in Oklahoma in 1931. Early water-flooding operations were confined to the area of shallow Bartlesville-sand formations in Nowata and Rogers Counties, where many of the projects were outstandingly successful. The results of these operations stimulated activities in other pools in Oklahoma, and by the end of 1949 water flooding had been tried in 25 of the 49 oil-producing counties in the State (fig. 1). Approximately 33 million barrels of oil, or 1,806 barrels per acre, had been recovered by December 31, 1949, from 18,221 productive acres included in the 162 active and abandoned projects in Oklahoma by injection of approximately 449 million barrels of water.

Jan 1, 1952

By M. D. Carver

The purpose of this investigation was to determine the effects of variations in content (near the residual level) of the impurities aluminum, nitrogen, manganese, and copper on the corrosion rate in pressurized hot water and in pressurized steam of zircaloy-3, a zirconium-base alloy of 0.25 percent tin and 0.25 percent iron. Thirty-five 10-pound ingots were cast with the appropriate additions of impurity elements, and these were converted to wrought sheets. These specimens were then tested both in water and in steam. The analysis of the resulting data showed that in environments of either pressurized hot water or superheated steam, corrosion rates increased with increasing content of aluminum, nitrogen, or manganese, but were not affected by variations of copper. The effects of aluminum and nitrogen were found to be greater than the effect of manganese. INTRODUCTION At the request of the Atomic Energy Commission (AEC) in August 1956, the Federal Bureau of Mines, in cooperation with Bettis Plant of Westinghouse Electric Corp., began investigating the effects of certain impurity elements on the corrosion rates of zircaloy-3 in pressurized hot water and in pressurized steam. It was necessary to know these effects in order to set control limits on residual impurity levels in zirnaloy-3, intended for heat transfer service in the nuclear reactor of the pressurized water type. A factorial expert it was designed by Westinghouse statisticians. The Atomic Energy Commission provided raw zirconium sponge purchased from Wah Chang Corp. The Bureau's laboratory at Albany, Oreg., made material of different combinations of impurity levels and subjected the material to corrosion tests. This report will describe the work done at the Bureau laboratory and will show, quantitatively the effects of different residual levels of aluminum or nitrogen, or manganese or copper on corrosion rates.

Jan 1, 1961

By G. R. Hopkins

A recently completed survey , made by the Bureau of Mines to determine the trend of fuel consumption at refineries in the United States , showed the following outstanding points : A decrease in the use of oil for fuel in 1927 of over 5,000,000 barrels as compared with 1926 ; a decrease in the use of coal of over : 1,000,000 short tons ; small increases in the use of both natural gas and refinery gas ; an increase in the use of petroleum coke . The decrease in fuel - oil consumption was approximately 2,000,000 barrels each in the Atlantic Coast , Texas , and Louisiana- Arkansas districts , with an increase of 1,000,000 barrels in the Indiana - Illinois district , or a net decrease of 5,000,000 barrels . The decrease in fuel- oil consumption by refineries in the Texas and Louisiana- Arkansas areas was offset largely by increased consumption of natural gas and refinery gas , whereas the increased consumption in the Indiana- Illinois region was more than offset by the decrease in coal consumption . The use of coal for fuel declined from 6,052,000 short tons in 1926 to 5,031,000 short tons in 1927. Practically all of this decrease was recorded in the Appalachian and Indiana- Illinois districts , which at the same time showed the largest percentage increase in the use of oil for fuel . It is probable , therefore , that although coal prices also fell off , a considerable quantity of oil replaced coal in this area in 1927. In addition , the group of refineries , which are by location more or less definitely committed to the use of coal for fuel , undoubtedly succeeded in saving a material amount of coal through the use of more efficient fueling methods . A total of 130,815,000,000 cubic feet of natural gas was consumed for fuel at refineries in 1927. This represents an increase of 8 per cent over the 1926 total . Nearly all of this increase resulted from the opening of a line from the Monroe field to Baton Rouge , La . Had this line not been opened , there would have been a decrease in the use of natural gas , as a number of districts , particularly the Rocky Mountain , reported decreases in its use . The use of refinery or still gases for fuel did not change materially during 1927 , there being a total of 52,807,000,000 cubic feet burned as compared with 52,077,000,000 cubic feet in 1926. Refinery gases are largely a product of cracking and , it was probably more than a coincidence that a few districts in which cracking slowed down in 1927 also reported less refinery gas used as fuel .

Jun 1, 1924

By William D. Monaghan

The U.S. Bureau of Mines evaluated a teleoperated continuous mining machine for deep mining in thin-seam applications as low as 1 m. Teleoperation increases the safety of mining machine operators because it removes the operator from the face, an area of immediate hazards to safer outby locations. By using teleoperation, the miner can avoid many including unexpected roof falls that can maim or kill miners instantly, methane and coal dust explosions that can be ignited with just a small spark or flame, adverse health effects from miners breathing coal and silica dust, adverse long-term inner ear damage from loud noise pollution, and other hazards related to heavy mining equipment moving about in confined underground roadways. This report presents the surface evaluation results of a teleoperated control system.

Jan 1, 1994

By D. R. Tesarik

The factor of safety, the traditional measure of stability for earth embankments, is graphically presented in factor of safety charts in this Bureau of Mines report. Factor of safety contours are drawn for homogeneous earth embankments for two contrasting situations: (1) no phreatic surface and (2) a phreatic surface that assumes 10-pct freeboard. The factor of safety can be read directly from the charts if the physical properties of the soil and the geometry of the embankment are known. The curves provide a quick first approximation of the "most stable" and "least stable" condition of the embankment. The Simplified Bishop Method was used for the safety factor calculations, and a sequence of least squares curve fitting steps was used to present the factor of safety in final chart form.

Jan 1, 1981