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By F. D. Osgood, H. M. Cooper, A. C. Fieldner

The analyses in the tables are arranged geographically with respect to county and towns, and are grouped as follows: l The proximate analysis--moisture, volatile matter, fixed car bon, and ash; 2 The ultimate analysis-carbon, hydrogen, nitrogen, oxygen, sulphur, and ash; 3 The calorific value of heat of combustion; 4 The softening temperature of ash, when such determinations were made. Ultimate analyses are given in three conditions-namely, (1) as received, (2) moisture free, and (3) moisture and ash free Proximate analyses and heating values are given generally in one condition -namely, as received, some are in two conditions, as received and moisture free.

Jan 1, 1928

By J. K. Whyatt, B. G. White

Various methods of monitoring slip movements on bedding planes, as well as examination of rock burst damage in stopes, suggests that rock bursts in the Lucky Friday Mine are closely associated with these movements. Slip displacements along bedding simultaneously reduce the physical dimensions of stopes and increase compressive stress along stope margins. Such changes, in turn, contribute directly to rock bursts and the sudden failure of volumes of rock and cemented sandfill surrounding stopes. The distribution of seismicity and several mining-induced and premining structures resemble those described in South African gold mines. These suggest fundamental similarities in seismic sources and mechanisms of rock burst damage.

To improve the efficiency and speed of under-ground post-disaster rescue operations. The Approach: Develop a battery-powered mine-rescue vehicle designed to carry rescue crews, rescued miners, and their support equipment. How It Works: The experimental vehicle, shown below, was designed and constructed by the Mine Safety Appliances Company under contract to the Bureau of Mines. ATV Manufacturing Company and Delco Electronics were subcontractors. A rechargeable, silver-zinc battery provides power to a 3-horsepower permissible motor, the speed of which is regulated by a solid-state controller. Three wheels on each side are independently driven by a chain and mechanical trans-mission.

Jan 1, 1974

Rapidly identify unstable mine waste embankments and similar dam structures. Approach Aerial photography, geotechnical instrumentation, and telephone or satellite data transmission are used to supplement walk-around inspect ions. How It Works Embankment stability and other indicators of structural integrity are evaluated using aerial photography, and on-site unattended instruments and data transmitting systems. Evidence of external movement and water seepage is obtained from aerial photography and photogrammetric evaluation techniques. Surface points marked by stake- mounted targets are monitored photographically at time intervals of several weeks or months. Photographic measurements of x, y, and z coordinates of these points are obtained from flying a series of photo-runs over the dam.

Jan 1, 1979

By B. E. Davis

As part of its program to increase the domestic availability of critical minerals, the Bureau of Mines conducted characterization and beneficiation studies on a St. Johns County, Fla., phosphate ore that was mined by borehole mining. Results revealed that the ore from this test mine was mostly sand-size carbonate-fluorapatite and quartz and contained 24.6 percent P205. Concentration by various flotation techniques produced phosphate concentrates that ranged, in percent, from 30.0 to 31.4 P205, 0.73 to 0.80 MgO, and 2.8 to 7.2 acid insoluble. Recovery of the phosphate from the ore ranged from 89.4 to 96.3 percent.

Jan 1, 1982

By C. E. Jordan

The Bureau of Mines conducted tests on seven samples of Florida phosphate operations.slimes to develop a method to recover phosphate presently being discarded because of its small grain size. A system of hydrocyclones and hydroseparators was used to recover up to 96 pct of the plus 400-mesh material from the slimes. This plus 400-mesh material was subjected to fatty acid flotation, and concentrates containing up to 33.4 pct P205 were produced. As much as 88 pct of the phosphate (P205) was recovered from the plus 400-mesh material, and up to 29.6 pct was recovered from the total slimes.

Jan 1, 1982

By Harold F. Unger

The Bureau of Mines conducted drilling experiments in the laboratory with a commercially available percussive drill that has an independent rotational system. Eight rock types with a wide range of physical properties were drilled under several combinations of rotational speed, drilling thrust, and operating pressure. Penetration rates and energy per unit volume correlated well with the coefficient of rock strength as shown graphically. Size-distribution analyses of some of the drill cuttings show how particle size varies with rotation speed and rock hardness. In general, changing the rotational speed has a greater influence on the penetration rate in softer rocks, with penetration rate increasing with increasing rotational speed.

Jan 1, 1972

By W. S. Sanner

A High Splint coal was carbonized in a low-temperature, fluidized-bed sys-tem to study the effects of thermal cracking on the products of decomposition. The coal was fluidized in recycle gas at 485° to 600° C, and the products were cracked at 600°, 700°, and 800° C in a bed of fluidized coke. Yields of tar, pitch, paraffins, and olefins decreased as carbonization temperature increased. Thermal cracking of the tar vapors produced the highest tar yields at 600° C, and light oil yield increased at cracking temperatures up to 700° C. At an 800° C cracking temperature, the yield of light oil decreased.

Jan 1, 1969

By George H. Johnson

An evaluation of the diamond-bit-performance data accumulated from core-drilling cherty limestone and cherty dolomite reveals that the percentage of core recovered and the physical characteristics of the bits and diamonds used are economically significant. One of the established trends, of particular interest to those engaged in diamond drilling, is that bits set with small, low-quality, West African drill bort are the most economical. Detailed analysis of the factors that affect diamond-bit performances, such as diamond size and quality, bit size and type, percentage of core recovered, and the physical characteristics of the bit matrices are assessed in the tables, charts, and discussion.

Jan 1, 1958

By James P. Rider

This U.S. Bureau of Mines report describes a viewing transformation algorithm that generates a perspective view of a three-dimensional scene. This tool may be used by researchers to improve mine safety by assessing the visual capabilities of a mobile equipment operator. Three-dimensional transformations used to build the viewing transformation and techniques used to project the image onto a two-dimensional display screen are defined. The algorithm is written in the C-programming language and designed to stress portability, allowing it to work without significant modifications on numerous computers. A listing of the computer routines along with sample output is included in the report.

Jan 1, 1992

By Michael J. Gallagher

Diamond-bit performance data accumulated by the Bureau of Mines in core-drilling limestone and dolomite show that the physical characteristics of the diamonds and the sizes and types of bits used are economically significant. An analysis of the data establishes one trend of particular significance to those engaged in core drilling: Bits set with small, low-quality drill bort are the most economical. Detailed analysis of the factors that affect diamond-bit performance, such as size and quality of diamonds, sizes and types of bits, percentage of core recovered, and physical characteristics of bit matrices are assessed in the tables, bar charts, and discussion.

Jan 1, 1958

By W. L. Hunter

Eleven steelmaking heats are described in this Bureau of Mines report in which acid practice was used to produce carbon steel from pre reduced iron ore pellets. Furnace slags obtained with no flux addition to the charge became quite viscous as they cooled, which precluded pressure casting from a ladle. Lime was added to the furnace charge at two levels to eight of the heats to modify slag characteristics in the furnace, and to the ladle in two heats to further modify the ladle slag cover. Selected ingots from nine heats were successfully rolled on a commercial mill to produce No. 10 reinforcing bar.

Jan 1, 1974

By C. W. Dwiggins

The Bureau of Mines characterized the chemical and physical properties of metallo-organic materials in petroleum to determine their effect on petroleum production and refining. The structures and physical properties of porphyrins and materials that normally contain metalloporphyrins such as crude oils and asphaltenes were investigated using elemental analysis, NMR analysis, absorption spectrometry, and small-angle X-ray scattering. Petroleum fractions greatly enriched in metalloporphyrins were obtained using asphaltene precipitation, liquid extraction, and large-scale liquid-solid chromatography. Selected fractions containing porphyrins were further purified by chromatographic methods, crystallization, and demetalation followed by chromatography. Nonporphyrin metals could not be appreciably concentrated from the bulk of the asphaltene.

Jan 1, 1969

By Owen W. Terry

During the summer of 1943 the Bureau of Mines conducted an investigation and program of churn drilling on the McIlhon and adjoining Pearson land in the Mineral Point district of Iowa County, Wis. Sixteen holes, aggregating 1,570 feet .of bore, were completed. The work was undertaken as part of a general investigation of the zinc-and lead-producing area of southwestern Wisconsin at a time when great effort was being made to increase the production of Metals important to the war program. The Bureau's drilling program supplemented a previous drilling pro-gram conducted by the Vinegar Hill Zinc Co., and demonstrated the presence of a strongly mineralized zone at relatively shallow depths.

Jan 1, 1948

By F. W. Cox

Exhaust emissions were measured from 25 aircraft turbine engines using Jet A fuel. Analytical apparatus, procedures, and results are described. Carbon monoxide, carbon dioxide, nitric oxide, nitrogen dioxide, and aldehydes were measured at engine operating modes representing power levels used in airline operation. Carbon monoxide, hydrocarbon, and aldehyde emissions were highest at idle and lowest at takeoff; oxides of nitrogen were lowest at idle and highest at takeoff. Of the total oxides of nitrogen emitted, nitrogen dioxide constituted from 10 to 100 pct, depending on the exhaust gas temperature. Engines retrofitted with smoke-reducing burner cans produced less carbon monoxide, hydrocarbon, and aldehyde emissions, and slightly more oxides of nitrogen then engines with standard burner cans.

Jan 1, 1972

By M. K. Larson, J. K. Whyatt, F. M. Jenkins

The U.S. Bureau of Mines conducted an overcore stress measurement on the 5300 level of the Lucky Friday Mine, Mullan, ID, to investigate the stress regime around an experimental stope in a rock-burst-prone mine. The result indicated a stress field with unexpected magnitude and orientation [F . 135 MPa (19,600 psi) oriented S 80E1W]. An unusual amount of rock-burst activity was encountered during subsequent excavation. A careful review of the overcore data suggested the overcore strain measurements were valid. Moreover, concentrated rock-burst activity suggested that the measured stress field did exist, but was localized and therefore did not represent the far-field in situ stress field.

Jan 1, 1995

By J. R. Allsup

The Bureau of Mines studied the characteristics of simulated coal gas as an automotive fuel in two multicylinder vehicles in a standard and high-compression-ratio engine configuration. While using simulated coal gas fuel, increasing the engine compression ratio improved the fuel economy and vehicle performance but increased hydrocarbon emissions by 40 pct. photochemical reactivity of exhaust hydrocarbons was found to be extremely low using the coal gas fuel. An oxidizing catalyst used with the simulated coal gas fuel eliminated all but trace amounts of carbon monoxide and reactive hydrocarbons in the exhaust. Spark gap geometry and firing voltage were varied and, within the range tested, had little effect on vehicle performance and emissions using simulated coal gas fuel.

Jan 1, 1975

By C. P. Lazzara, Y. Miron, A. C. Smith

This report presents a U.S. Bureau of Mines study to identify the causes of self-heating events beneath the floor of a deep underground coal mine. Mine samples from both heated and unheated areas were examined by various techniques, including visual, microscopic, thermal, chemical, and instrumental tests. The combined results led to the conclusion that pyrite (FeS2) oxidation was the prime cause of the beatings. However, adiabatic oven tests of selected samples did not indicate the effect of the pyrite on the self-heating process, probably because of the experimental conditions. A fast, simple procedure to assess the concentration of pyrite in the mine samples was developed, utilizing the reactivity of the sample with an aqueous solution of hydrogen peroxide (H2O2)

Jan 1, 1992

By Fred N. Kissell, Maurice Deul, T. D. Moore

Methane emission from two surface gob-degasification boreholes was measured by the Bureau of Mines. The investigation took place during mining of a 3,200-foot longwall panel in the Lower Kittanning coalbed in central Pennsylvania. The first hole was 500 feet from the start of mining, and the second hole was 2,200 feet. The first hole went on natural draft as soon as the longwall face passed it. This caused the methane flow in the return entries to drop 75 pct. In the 6 months required to complete the panel, the two holes emitted 69 MMcf of methane in varying percentages of concentration in air. In 3 years, the holes emitted a total of 150 MMcf of methane.

Jan 1, 1976

By Arthur M. Hartstein

The Bureau of Mines through contract with Ultrasystems, Inc., obtained gram per gram data of products formed on thermal oxidative degradation of selected compositions, both under dynamic and static conditions. Four broad classes of materials were studied! Polyvinyl chloride compositions, neoprene compositions, rigid urethane foams, and variously treated woods. Whenever possible, comparisons between pure components and composites were attempted. Thermogravimetric and differential thermal analyses were performed to gain understanding of the processes occurring and to explore the feasibility of using these analyses as a method of material identification. The toxic products detected and quantitated included HC1, H2S, CO, S02, CS2,COS, HCOOH, CH3COOH, formaldehyde, acrolein, C 6H6, chloroprene, chloroethanol, benzyl chloride, aniline, and furfural.

Jan 1, 1974