Search Documents

By Henry M. Harris

The Bureau of Mines investigated a glass containing approximately 17 percent lithia and 83 percent silica to establish a method of devitrifying cast and rolled shapes. Glass shapes with high strength were made by melting, forming, and rapid cooling of the composition, and the shapes subsequently were converted to a crystalline condition by heat treatment. The best devitrification schedule included rapid cooling of the glass to below 300° C, followed by reheating at a rate of 50° to 400° C per hour, depending on the size of the shape, followed by a of 60 to 70 hours at 500° C and another period of 15 hours at 800° C. attempts to use faster heating rates or slow cooling to accomplish devitrification in deformation of the shapes. The crystalline shapes had flexural strengths that averaged over 33,000 psi, achieved with an annealing time of 60 to 70 hours at 500° C.

Jan 1, 1965

By Franklin D. Cooper

This chapter includes tables for 1979 that were not available in time for publication in the 1978-79 Minerals Yearbook, but it does not include corresponding tables for 1980. The value of raw nonfuel mineral output in 1980 was estimated at $24.8 billion, 8.5% above the 1979 value. Of the 21 metal commodities produced, quantitative output increased for 11 and decreased for 10. The values for 10 metals were up, 10 were down, and 1 was unchanged. Among the 47 non-metallic commodities produced, 14 showed quantitative increases, 32 declined, and 1 was unchanged. In terms of value, 32 nonmetallics increased, and 15 declined.

Jan 1, 1981

By W. D. Bryson

This paper is one of a series being prepared by the United States Bureau of Mines on tunnel-driving methods. The practices described are those used at No. 11 mine of the Colony Coal Co., Denver, Colo. No. 11 Mine is situated at Dines, some 14 miles north of Rook Springs, in Sweetwater County, Wyo. It is served by a spur off the Winton branch of the Union Pacific Railroad. The Colony Coal Co.'s mines were opened in 1918, and since that time have been among the largest producers of coal for the railroad and domestic markets in the Rock Springs coal district.

Jan 1, 1932

By E. Chin

Natural gas was the only economically significant mineral produced. A significant amount of the gas output was consumed in the production of nitrogen fertilizer and electric power. Proved reserves of natural gas were abundant and at least sufficient to supply most of the country's industrial and domestic needs for many decades to come. Other mineral production was of little importance to the Bangladesh economy, although there were prospects for developing some of the nonmetallic minerals. The flat river-delta terrain comprising nearly all of Bangladesh made the potential for discovering major, economically exploitable mineral deposits poor. The deep sediments, however, have good potential for crude oil or additional natural gas discoveries.

Jan 1, 1985

By C. W. Owings

When explosions have occurred in mines where rock dust has been used to some extent, generally to a very limited extent, the press has immediately characterized those mines as "rock-dusted." To persons familiar with the method of rock-dusting, it is apparent that if rock-dusting is done properly, if all mine surfaces are rock-dusted to within at least 40 feet of the faces of rooms and entries, and if the incombustible content of the dust is more than 65 per cent, there is little likelihood that an explosion of coal-dust will occur. The report that an explosion has occurred in a "rock-dusted" mine immediately conveys to the mind of the alert safety advocate the information that the mine is inadequately rock-dusted or that either dust sampling of the rock-dusted surfaces has not been done or, if done, the mine has not been redusted with sufficient promptness. Rules for Collection of Samples Collection of dust samples is by no means intricate, but a few simple rules must be kept in mind if the results are to be dependable. A sample must represent the true average conditions of the dust in the section or zone in which it is taken, and therefore 'the point at which the sample is to be collected must be selected with care. During an explosion much if not all of the dust on the ribs, roof, timber, and road in the affected region is blown into the air; the sample, therefore, should contain all loose dust and material on: the surfaces to a depth of about 1 inch, if that amount is present. If there is considerable sand locally along the track, care must be taken not to include enough of this material to vitiate the sale and distort the results; however, if the sand is distributed throughout the region being sampled it should be included. Dust should not be collected from recesses in the ribs, such as hitches cut for timber, as the character of the dust in such places is often different from that on the ribs proper. Samples should not be collected at points where the dusting machine has been loaded or at a point where the machine has stopped and discharged for a longer period than at other points on the entry or in the rooms. In short, the sample must represent AVERAGE CONDITIONS, and if there is any doubt as to the character of the dust it is far better to have too much combustible matter than too much incombustible matter in the sample, as it is best to err on the side of safety if it is necessary to err.

Jan 1, 1929

By David R. Hanson

Experimental work performed by the Bureau of Mines in a laboratory environment has shown that the formation of failure zones within certain rock types is accompanied by the emission of significant amounts of radiofrequency (RF) electromagnetic (EM) energy. This radiation was detected using nonresonant, "electrically short," broad-band antennas. Rock types for which emission was observed include granite, quartzite, and taconite; sandstone and marble did not emit measurable radiation. Amplitude spectra of the radiation showed the energy to be concentrated between 10 and 40 kilohertz. These data indicate that emission is directional, but this has not yet been proven. In addition, amplitude of RF emission increases with increasing crack size. Since emission was observed only for brittle quartz-bearing rocks, it appears the formation of piezoelectric fields is a necessary condition for RF radiation. Plausible mechanisms for emission include rapid decay of piezoelectric fields accompanying the sudden stress release at failure and/or the acceleration of an "exoelectron plasma" through the intense local piezoelectric fields. Since emission appears to increase with the scale of failure, and since antennas do not need to be coupled directly to rock surfaces as with conventional geophones, the possibility of developing a portable system to monitor seismically active areas exists.

Jan 1, 1981

By J. W. Walkiewicz

One of the objectives of the Bureau of Mines is to develop substitution technology for scarce materials. In accordance with this goal, alloys containing lanthanum, cobalt, copper, and magnesium were investigated for fabrication of rare-earth-cobalt (RE-Co) permanent magnets. A complete substitution of lanthanum for samarium and a partial substitution of copper for cobalt was accomplished. Magnets of La-Co and La-Co-Cu-Mg alloys were fabricated by powder metallurgy techniques and evaluated. A maximum intrinsic coercivity of 23.2 kOe was obtained with a La-Co-Cu-Mg alloy. In comparison, maximum values of 9.3 kOe and 11.6 kOe were obtained with La-Co and La-Co-Cu alloys, respectively. The substitution of copper and magnesium for part of the cobalt resulted in a large increase of intrinsic coercivity, similar to the results of Bureau research with mischmetal-Co-Cu-Mg alloys. Unlike the mischmetal-Co-Cu-Mg magnets, the La-Co-Cu-Mg magnets showed signs of physical deterioration on exposure to air. The effects of fabrication parameters on the magnetic properties of the La-Co-Cu-Mg alloys were also determined.

Jan 1, 1982

By F. L. Klinger

CRUDE OIL refining continued to be the foremost industry of Bahrain in 1963. This island, the largest of a group 30 kilometers off the Saudi Arabian coast, is the site of the first petroleum discovery in the Persian Gulf and in the Arabian peninsular region. The island's only oilfield was discovered in 1932; exports of crude began in 1934 and the refinery was built in 1936. Although its crude oil has been less than 1 percent of annual Middle East output in recent years, Bahrain has been an important refining center for many years, processing a substantial portion of Saudi Arabian petroleum as well as all local production. The Bahrain refinery annually accounts for 17 percent 0 the petroleum products produced in the Middle East and 25 percent of the exports. Bahrain's mineral resources consist of oil, gas, and basic construction materials. Petroleum production and refining are the important mineral industries and contribute most of the national income by payments for taxes, wages, and local services including construction and material supply. The petroleum industry has supported a large share of local business and extensive indirect employment, and its early establishment also helped Bahrain to strengthen its position as a trading center in the Persian Gulf. The country's entrepôt trade produces about 20 percent of Government revenue, and Bahrain is somewhat less dependent on the petroleum industry than are the neighboring States to the west.

Jan 1, 1964

By C. M. McKinney

Sulfur content data from Bureau of Mines routine analyses of 1,060 United States crude oils were used with crude oil production data for the years 1956-66 to prepare tables and charts that illustrate the volume and percentage distribution according to sulfur content of crude oil produced in 10 geographical areas of the United States. Similar relationships for foreign crude oils based on analyses of 201 crude oils and production during 1966 are illustrated for Africa, Canada, Middle East, and South America. Tables are included giving field name, sulfur content, geologic name and age of producing formation, depth of producing formation, and production during 1966 for 882 United States crude oils and 201 .foreign crude oils. Between 1955 and 1966 the average sulfur content of crude oils produced in the United States decreased from 0.73 to 0.67 percent.

Jan 1, 1967

The head loss data for coal slurries over a range of concentrations and velocities and the laboratory screen analysis were selected as areas for investigation in the data analysis performed. The analysis resulted in the following: (1) Size distributions for the coal used in the horizontal pipeline tests were fitted to the Rosin - Rammler distribution function. Each of the fits was significant. Corresponding Rosin - Rammler parameters were obtained which were introduced into the regression analysis. (2) A regression equation was obtained which predicts the slurry head loss of 1-inch by 0 coal slurries ranging in volumetric concentration from 20 to 40 percent and line velocities from 1 to 14 feet per second as a function of the square of velocity. The addition of the term for concentration in the regression equation did not contribute significantly c head loss.

Jan 1, 1972

By Basil Dimitriades

The association of automotive fuel composition with exhaust reactivity was studied in an experimental program that involved testing with different automotive engines and with gasolines of varied composition. Results showed clearly the exhaust reactivity to increase with increasing levels of polyalkylbenzenes in the fuel. No other systematic patterns of high significance were detected in the association of exhaust reactivity with several broadly defined groups of fuel components. For the purposes of this study, had it been possible, fuel composition should have been defined and expressed in terms of component groups such that the potential for exhaust reactivity would be the same within each group and different from group to group. Classification of fuel components in terms of the paraffins-olefins-aromatics groups does not meet the latter requirements. For appropriate classification of fuel components more information is needed on the combustion .of hydrocarbons in the multicylinder internal combustion engine. Statistical analysis of the mass emissions data showed significant car and fuel effects on hydrocarbon, carbon monoxide, nitric oxide, total aldehydes, and formaldehyde emission levels and on total photochemical reactivity. Car-fuel interactions were not significant at the 90-pct level. Correlations were found between mass emission parameters and fuel composition.

Jan 1, 1973

By Francis Crowley

Elementary concepts of seismic wave properties are reviewed to establish a framework for discussing seismic noise and its suppression. A liberal number of references is included for those who wish to pursue the topic in detail. A base motion noise level is established for a single surface seismometer. It is argued that simple array processing and seismometer burial should regularly permit us to approach this base noise level which is found in areas free of conspicuous man-made seismic noise sources. The sensitivity of the base seismic level to a number of common disturbances is presented. Solutions that promise to hold the "effective" seismic noise at a site near the base level are given for acoustic, meteorological and fixed local surface sources. Guidelines are suggested for controlling other local man-made sources, e.g. vehicular traffic, by keeping them at sufficiently large distances away from the seismometers to keep noise at permissible levels. These guidelines are speculative and conservative. They should be the subject of future study. The ability to process against general local activity, drilling, and intra- mine sources is limited. Certainly no dramatic gain is to be expected. When strong man-made and/or intramine noise sources are not controllable, detection may well be impossible to achieve, unless the seismometer can be moved close enough to the suspected miner position, i.e. via very deep holes, to compensate for the likely vast differences in strength of the miner signal and the uncontrollable man-made noise sources. However, many intramine sources, e.g., falling water, rock bursts, explosions, etc., may well preclude the existence of a hale miner in their vicinity, and therefore any need to attempt detection of a miner at such locations. The following recommendations are made to enhance the detection and location of a miner signaling seismically. They are: 1. Seismometer burial in slim holes. 2. Narrow band detection, using multiple narrow band filters to cover the likely signal band. 3. Broadband recording and analysis for time-of-arrival estimation.

Jan 1, 1974

By Stephen D. Cramer

The Bureau of Mines conducted a series of in situ linear polarization measurements in high-temperature, high-pressure hypersaline geothermal brines at the Bureau of Mines Geothermal Test Facility in the Imperial Valley of California. The measurements represented an evaluation of the linear polarization technique for obtaining instantaneous corrosion rates of materials of construction in flowing hypersaline hydrothermal fluids that rapidly form scales on exposed surfaces. A special method was devised for use with the linear polarization technique that resulted in obtaining corrosion rates for 1020 carbon steel, 316 and 430 stainless steel, titanium, various nickel-based alloys, and aluminum 6061 under strong scale-forming conditions. The measurements also provided information on scale-deposition rates in various geothermal environments. Exploratory in situ potentiostatic polarization measurements were made in the flowing brines to qualitatively determine scale-deposition effects on the electrochemical measurements.

Jan 1, 1978

By A. L. Murray, C. A. Allen

"In the Spring of 1919, the Industrial Commission of Utah undertook the assembling of safety orders covering metal mining operations Just at that time there appeared several articles in the mining papers advocating the licensing of hoisting engineers, so this subject was given careful consideration,The licensing of hoisting engineers means that they must pass an examination covering the mechanical features of hoists and boilers, and must have a certain amount of experience. This undoubtedly serves to get a class of hoisting engineers that are better informed about the mechanical operation and theoretical considerations in hoisting and the only room for argument against it is that it is difficult to give an examination that will determine whether or not a man is a competent hoisting engineer.A man might pass an excellent examination yet be absolutely unqualified to operate a hoist and the judgment of the mine super- intelligent would have to be depended upon to choose the right man from among those who were licensed. This difficulty of properly determining, by ordinary examination, a man's qualifications to run a hoist caused the idea of licensing' in the ordinary sense of the word to be abandoned; but, as there was no question that a hoisting engineer should be physically fit, it was decided to require a medical examination, and at the same time to require the hoist engineer to state his experience, so the State would better knowledge of his general qualifications.The orders covering the question were therefore issued as follows;"

Jan 1, 1920

By Mark I. Copeland

The Bureau of Mines discovered that silicon and nickel additions can prevent the formation of copper alloys of Sn, Sb, and As on the surface of steel during reheating to hot-working temperatures. When molten, these copper alloys cause surface hot shortness during hot working. Wrought steels were reheated isothermally and by simulated industrial practice; the resulting surfaces were metallographically evaluated. The steels contained, In weight-percent, 0.20 C, 0.45 Mn, and up to 1.00 Si, 1.00 Cu, and 0.15 Ni, and up to 0.30 Sn, Sb, or As. The larger the Cu, Sn, Sb and As content of the steels, the greater the amount of silicon necessary to prevent copper alloy formation. A content of 0.10 Ni considerably decreased the amount of silicon necessary for copper steels containing tin and antimony, but not for those containing arsenic. Theories for the beneficial effect of silicon and nickel additions are presented.

Jan 1, 1975

By Manuel Gomez

Areal distributions for ash, total sulfur, and sulfur forms were developed for the top 12 inches, the middle section, the bottom 8 inches, and the total seam of Pittsburgh coal in southwestern Pennsylvania. The sulfur and ash exhibit an apparent high local variability. As a general rule, both the sulfur and ash show high concentrations in the top 12 inches and in the bottom 8 inches of the seam relative to the concentrations observed in the middle section of the seam. The high-low sulfur and ash concentrations in the top 12 inches of the seam are not coincident with the high-low sulfur and ash concentrations in either the middle section or the bottom 8 inches of the seam. With respect to sulfur and ash, it is suggested that the top and bottom sections of the Pittsburgh coal may reflect both a syngenetic and epigenetic origin. Present data support the belief that paleotopography controlled Pittsburgh seam deposition. Evidence is presented to show that channels were cut at various times into the semilithified sediments that buried the Pittsburgh seam. In this channeling process, portions of the Pittsburgh coal may have been eroded away. Following channel development, the lower part of the Pittsburgh sandstone filled the complex system of braided channels to produce the "want areas" encountered in present mining operations. In localized areas of the Pittsburgh seam, impingement of Pittsburgh sandstone may be responsible for the lateral displacement of the coal. Information of this type becomes important in the assessment of exploration data, in the development of a quality control system for mine output, and in mine life planning.

Jan 1, 1974

By E. J. Matson

"SUMMARYThe Bureau of Mines has been investigating deposits of critical and essential minerals in the United States since 1939. Projects were set up on only the most promising properties. A preliminary examination of the Rio Grande property was made by Bureau of Mines engineers in July 1942 and the property was examined again in July 1943.The Geophysical Branch of the Bureau undertook a Geophysical survey of the area in November 1943 and was intermittently active in the district until June 1946. The major portion of their work was done from June 191 to November 1945. Favorable areas for exploration were recommended by the Geophysical Branch of the Geological Survey, 3/ and all holes were drilled in them.Two projects were set up by the mining branch in an endeavor to find ore bodies on the strength of the geophysical information."

Sep 1, 1947

By R. P. Beyer

[The Bureau of Mines has measured the low-temperature heat capacities and high-temperature enthalpies of crystalline K2Si2O5 as part of a program for advancing mineral resources technology with energy economy. High-temperature enthalpies of glassy and liquid K2Si2O5 and crystalline K2SiO3 were also mea¬sured. An adiabatic calorimeter operating over the range 5 to 308 K was used for the heat capacity measurements for K2Si2O5 from which the standard entropy at 298.15 K, S°298 = 45.55 ±0.05 cal/deg-mole, was calculated. Tabulated values of Cp°, S°, -(G° -HO°)/T, and H°-HO° from 5 to 300 K are given for K2Si2O5. A copper-block drop calorimeter was used in the enthalpy measurements, operating from 298.15 to 1,198 K for K2SiO3 and from 298.15 to 1,453.8 K for K2Si2O5. No transitions were found for K2SiO3. The KI2Si2O5 showed two reversible first order transitions, one at 510 K with a heat of transition of 0.29 kcal/mole and one at 867 K with a heat of transition of 0.38 kcal/mole. The heat of fusion for K2Si2O5 20 5 was calculated to be 8.42 kcal/mole. Relative enthalpies are given in equation form, and high-temperature values are tabulated for Cp°, S°, - (G°-H°298 )/T, and H°-H°298 . Also tabulated are ?H°, ?G°, and log K for formation of K2SiO3 and K2Si2O5 from both the elements and the oxides.]

Jan 1, 1979

By Thomas C. Miller, Charles E. Mongan

"This publication is a progress report on Bureau of Mines studies in applying sonar techniques to roof-control problems in coal mines. Preliminary tests in the laboratory were made on layers of roof rock. To apply the experience thus obtained, a unit was designed and constructed and was used underground.The term ""sonar technique"" refers to the system of generating a beam of sound waves, shaping and directing the beam, introducing the beam into a medium to be studied, and examining any returning waves with a view of inferring the nature of the material traversed by the waves and the presence of interfaces or obstacles in the medium.The theory and actual underground experiments indicate that the sonic method is feasible. Information from physical tests made in the Bureau's Experimental mine confirmed the validity and potential usefulness of the sonar method. Lighter and more compact apparatus is desirable, and permissible equipment suitable for use in gassy or dusty mines must be developed. However, no particular difficulties are anticipated; consequently, this scientific approach to the exploration of roof strata shows definite promise. INTRODUCTIONThe problem of roof control in the coal-mining industry is of major importance. More than 50 percent of all coal-mine fatalities and 25 percent of all nonfatal serious injuries are caused by falls of roof, face, or ribs. The Bureau estimates that more than $128 million was spent by the coal-mining industry in 1958 for supporting roof."

Feb 1, 1960

By J. W. Faul

[The Bureau of Mines initiated an extensive research on coal-mine ventilation factors in 1922, large- scale tests being conducted in its experimental nine near Bruceton, Pa., over a period of two years. A comprehensive report an this work is in course of preparation, but in order to place the practical results before the mining fraternity immediately and in condenses form, the more important features will be presented in a number of short papers. The present report is the first of a series dealing with the resistance of coal-mine entries to the flow of air and considers only entries in which there are no obstructions other than the natural roughness of the ribs, roof, and floor.]

Jan 1, 1924