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By S. C. Tadolini, T. M. Barczark

Mines in the western United States have had limited choices for standing support. Wood cribs were often too soft and unstable. The introduction of the Can support in the earl v 1990s provided an effective alternative, (lilt/ it remains the dominant form of tail¬gate support. Water-filled prestressing cells are now used to cap the Can and preload it to provide an active roof load. The Cluster Prop, consisting of three timber wedge props bundled to¬gether; provides more capacity than (m equivalent sized Call support and improves transport efficiency. However the Cluster Prop is less stable and does not maintain a consistent load throughout its loading profile. Pumpable roof supports are another alternative support, but the \' have not been proven in high deformation en¬vironments. This paper compares the performance characteristics o f these various support systems.

By Eleanor Abshire

[THE INCREASING use of hafnium as a vital component in atomic power reactors has brought this metal into recent prominence. A literature survey was made and this bibliography was compiled to provide research and production groups with a ready source of reference to this important metal anti its compounds. This service is rendered by the Zirconium Information Center, which is sponsored by the Department of the Navy, Bureau of Ships, and the F .S. Department of the Interior, Bureau of Mines, tit the Bureau's Northwest Electrodevelopment Experiment Station, Albany, Oreg. The following reference sources have been reviewed for this compilation : Chemical Abstracts; Industrial Arts Index; Crerar Metals Abstracts; Nuclear Sciences Abstracts; Bureau of Mine; Information Cicular 7771, Bibliography of Zirconium; anal Bureau of Mint' Information Circular 7830, Bibliography of Zirconium, suppllement to Information Circular 7771.]

Jan 1, 1960

By J. D. Ramsdell

To obtain information on the effects of cobalt on microstructure and tensile properties of titanium-vanadium-cobalt alloys, the composition ranges of 4 to 16 percent vanadium with 1 to 4 percent cobalt have been studied. The beta phase was not completely retained with vanadium additions up to 16 weight-percent or in the same alloys containing up to 4 percent cobalt.

Jan 1, 1960

By R. V. Ramani, W. Miola

"A relationship exists between the quartz contents in the underground coal nine airborne dust samples and those in the coal and host rocks that are mined [17, 18, 19] The prescribed method for quartz analysis in respirable airborne coal dust samples is the MSHA P-7 method. Accurate quartz analysis procedures are needed for bulk samples in order to predict the potential quartz content in airborne nine dust, which in turn will aid the design of quartz dust control procedures during mining. thereby reducing the airborne quartz dust in underground atmospheres. The requirements of this method are that the amount of quartz is the sample be less than 250ug, and the total sample weight less than 2,500 ug. Unlike with airborne dust samples, there are no limitations to the available mass of bulk samples. However, these are no standard procedures for the preparation of bulk samples for scanning or prescribed methods for quartz analysis. The NIOSH and MSHA methods are certified for roped* dust and the acceptance of these methods for bulk samples assumes that the bulk samples will be reduced to the conditions specified for respirable dust samples. An alternative method is X-ray diffraction, which provides higher average quartz values than those obtained from P-7 method for the same samples.An investigation was carried out to determine the optimal procedure for preparing the bulk samples for the IR and XRD analyses. In this paper, the investigations on the effects of calibration, particle sizes, matrix composition, interferrous, and behavior of the filter substances on IR, XRD and FTIR results are presented. The error introduced by the presence of kaolinite and a new sample asking procedure to reduce it are discussed. The problems experienced with conventional sample holders for scanning were eliminated with the design and development of a new hollow sample holder. Quantitative comparison of quartz determinations by IR, XRD and MR methods on coal, roof and floor rocks, and airborne dust samples are presented. The important factors affecting the results of quartz analysis methods are: 1) bulk sample preparation for obtaining representative and homogeneous analysis samples: 2) particle size distributions of the analysis samples and calibration standards; 3) qualitative matrix composition of the analysis sample; 4) matching calibration standards to analysis sample; 5) substrates for sample deposition during analysis sample preparation; 6) procedures for analysis sample mounting; 7) selection of proper portions of she response profile for insanity measurement; and 8) interferences of spurious phases with the critical analyses. The recommendations of this study are important to enable comparisons and interpretations of analysis and research results."

Nov 1, 1995

By Edmond Chin

The area encompassed by the political entities included in this study com-prises 11 million square miles or about 15 percent of the total Earth's land area. The bulk of the region is contained on the Asian continental land mass. Australia, the world's largest is-land or the world's smallest continent, alone is almost as large as the continental United States. The islands of New Zealand, New Guinea, Borneo, Sumatra, and Honshu are among the largest in the world. Collectively, they constitute a land area of 1.1 million square miles or an area about one-fourth the size of the United States. The region is noted for its great rivers. The Chang, Huang, Amur, and Mekong are respectively the fifth, sixth, eighth, and eleventh longest rivers in the world. The Ganges-Brahmaputra has created the world's largest delta, which covers 30,000 square miles. Abutting East Asia are the Sea of Japan, Dong Hai, Nan Hai, Bay of Ben-gal, and Arabian Sea. In the Southern Hemisphere, there is the Indian Ocean and the South Pacific Ocean. The Continental Shelf adjacent to the region constitutes a large proportion of the world's readily accessible shelf area. On the other hand, the Philippine and Java trenches and, further out, the Mariana Trench reach to formidable, abyssal depths, downward to 6,000 fathoms. Contrasting to this is Mount Everest, which reaches a lofty height of 29,028 feet. And then there is Xizang, whose high plateaus have been called the roof of the world.

Jan 1, 1992

By J. L. Holman

The Federal Bureau of Mines has conducted research to delineate factors affecting relative fabricability of electrowon and electrorefined copper. The Bureau's Rolla Metallurgy Research Center coordinated and participated in a statistical round-robin chemical analysis and performed impact tests on lead-doped copper specimens. In a series of round-robin analyses, cathode, bar, or rod from a domestic lot of electrorefined copper and electrowon copper from a domestic and a Peruvian source were analyzed for Pb, Fe, Bi, Se, Ag, O, S, Sb, and seven other elements. The electrowon cathode from both sources surpassed requirements for electrolytic cathode, although lead in the Peruvian lot exceeded specification for oxygen-free electronic grade. The least interlaboratory agreement was for oxygen analysis, Copper specimens, doped with up to ~300 ppm Pb and consisting of as-cast material (fine-grained or coarse-grained) and hot-rolled material, were impact-tested at temperatures to 871° C (1,600° F). Impact energy of fine-grained material dropped 26 pct with increased Pb up to 20 ppm and more gradually thereafter. Coarse-grained specimens fractured at lower energy with little dependence on lead. Hot rolling raised impact energy substantially. Grain structure is evidently as significant as lead in influencing workability. Some discussion is given of possible effects of oxygen, sulfur, and porosity.

Jan 1, 1978

Maintain good blowing face ventilation while taking deeper cuts with a radio-remote, scrubber-equipped miner. Approach A six week in-mine study of face ventilation effectiveness was made by comparing the existing MSHA-approved blowing curtain setback distance of 25 ft with brattice set back distances of up to 50 ft. Effectiveness was determined by measuring methane levels at the face and in the immediate return. How It Works Blowing ventilation systems are commonly used in mines because the high velocity air stream created by these systems rapidly mixes with and dissipates methane generated during the cutting of coal. A drawback to blowing ventilation is that the work area is placed in return air and this may create dust compliance problems for the shuttle car and mining machine operator. To clean dust from the return a number of mining machine manufacturers supply dust scrubbers built into the machine. Dust-laden air is drawn into ducting at the front of the mining machine's boom and is ducted to a scrubbing unit located on the machine's main frame. The clean air from the scrubber is discharged as a high velocity jet toward the return, generally from the left fender of the mining machine. When taking cuts deeper than 20 to 25 ft with a scrubber-equipped machine, the machine's discharge is in by the mouth of the blowing curtain, creating a concern by mine workers that a loss of air to the face could result. However, Bureau of Mines research found that the push or throw of air toward the return by the scrubber discharge jet allows good face ventilation to be maintained with extended curtain setbacks.

Jan 1, 1984

By Deno Pappas, Gregory Molinda, Eric Bauer, Christopher Mark, Daniel Babich

Groundfalls are much more likely to occur in coal mine intersections than in entries. NIOSH is using the experience of U.S. coal mines to determine the factors which influence intersection instability and provide guidelines for the safe excavation and support of intersections. Detailed field investigations have resulted in a database of U.S. coal mines containing 12 mines and 639 roof falls so far. By using the roof fall rate as the outcome variable, correlations between roof geology (CMRR), intersection span, and roof support have been established. Case studies have indicated that replacing 3- way intersections with 4-way intersections may not reduce the total number of roof falls. Additionally, the size of intersection spans tend to decrease with lower (weaker) CMRR. Protocols have been established for the collections of roof bolt parameters. The performance of individual roof bolts can now be tracked with roof fall rate.

By G. W. Groove, E. E. Quenon

"INTRODUCTION Uncontrolled mine fires originating in exposed coal beds through the acts of careless or irresponsible persons present a serious threat to buildings, surface property, and the life and health of persons near the affected area. Apparently, the seriousness of such fires is not fully understood by property owners or those residing in the vicinity, as practically nothing has been done to alleviate conditions. In many instances, such fires have been active for several years before property owners or civic organizations have shown any interest toward having the fire extinguished. Recommendations by Bureau of Mines investigators in the interest of controlling such fires are seldom followed, as the Bureau cannot provide the funds for doing the work.Several uncontrolled and widespread fires are burning along the outcrop of coal beds and in underground abandoned mine workings within a 25-mile radius of Pittsburgh, Allegheny County, Pa. If these fires are permitted to continue to burn unabated, the ultimate results may be far-reaching. Most of the outcrop fires investigated are believed to have originated from burning rubbish, forest fires, or workmen, hunters, or others building fires near the outcrop of ,the coal beds. In other instances, smoke and fumes have suddenly appeared in the vicinity of abandoned coal-mine openings, indicating that a fire has either burned its way along the outcrop of the coal bed or has traveled through the abandoned mine from another location. An underground or outcrop coal-mine fire will be very likely to continue to burn as long as an oxygen supply is present.; and, so far as is known, such fires do not stop burning automatically until virtually all combustible matter is consumed."

Feb 1, 1948

By Allan E. Martin, George Glocker, C. E. Wood

"INTRODUCTION As part of a comprehensive investigation of the mechanism of defurization of iron and steel by slags, the Blast Furnace Studies Section, Metallurgical Division, Bureau of Mines, in cooperation with the Institute of Technology, University of Minnesota, has made a study of the forms in which sulfur occurs in blast-furnace slag. This report presents data on the three sulfides most important in iron smelting, namely, ferrous sulfide, manganous sulfide, and calcium sulfide. The tendency of these sulfides to form colloids in the molten slag was determined by an examination of quenched samples with an ultramicroscope.Vogt/ conducted experiments on sulfide silicate melts and examined synthetic blast-furnace slags in a partly crystallized condition. His conclusions were that FeS, CaS, and MnS, or isomorphous compounds, such as (FexCay)S and (MnxCaa)S, were precipitated from the melt, depending on the composition of the slag. In all specimens sulfides were visible and were spherical.Coloration of glass by sulfur also provides indirect information on the nature of sulfur in blast-furnace slags./ There seems to be a general agreement at present among the workers in the field of colored glasses that ferrous sulfide is a strong color producer. Colors that have been attributed to this compound include yellow, orange, brown, blue, and black. Apparently the ferrous sulfide is considered to be dissolved in these glasses. There is no indication that any of them have been examined for a colloidal phase.Lorenz 7/ investigated a single manganese slag in the glassy state and observed a Tyndall beam in an ultramicroscope. His conclusion was that either a manganese compound had precipitated in a finely divided condition or that metallic manganese had volatilized and penetrated into the slag as a vapor and thus formed colloidal particles."

Feb 1, 1941

By Andrew B. Cecala, Edward D. Thimons

The Bureau of Mines has successfully tested a method to simulate methane (CH~) flows from face areas through the returns of noncoal mines. This technique' involves releasing a small quantity of tracer gas at a working area and sampling for that gas downstream in the re- turn airways. By measuring the dilution of the tracer gas, the dilution of any volume of CH4 released at the face can be calculated. This information is useful in selecting locations for CH4 monitors and in deciding the necessity for permissible equipment in the returns.

Jan 1, 1984

By George A. Morgan

The production and processing of crude petroleum and natural gas are the dominant economic sectors of the Middle East. The IS countries that constitute the region accounted for 26% of world crude petroleum output, 17% of world natural gas plant liquid production, and almost S% of world dry natural gas production. About 66% of total world crude petroleum reserves and 31 % of total world natural gas reserves are in the Middle East. Transportation and port facilities in the region are geared to expediting efficient and rapid shipment of these materials. U.S.-dollar-denominated export sales of these fuels, estimated at $120 billion in 1989, provide funding for further diversification of the mineral industry. This is usually through development of downstream facilities for producing energy intensive metals such as aluminum and byproducts of the fuels such as petro-chemicals and fertilizers. Earnings from the industry are also channeled by sever-al Governments in the region to mineral industry projects in Africa and elsewhere. A fairly wide range of nonfuel minerals is produced in the region. However, the variety of minerals produced, output levels, and the size of the overall nonfuel mineral economy is dominated by Iran and Turkey. Turkey, with a diverse mineral production and strategically situated between Europe and the Middle East, ranked among the top three world producers of boron, chromite, pumice, and strontium. It was also a significant world producer of magnesium com-pounds, mercury, and sodium sulfate. Iran had generally lower output owing to 9 years of neglect to the mining sector between 1979 and 1988. It was a significant producer of gypsum and fifth in world production of strontium. Despite a very small domestic mineral industry, Israel was second in world production of bro-mine and a significant producer of phosphate rock and potash. Jordan ranked fifth in world production of phosphate rock. Iraq ranked about eighth in world production of sulfur, a commodity of major importance in the metallurgical, petrochemical, and fertilizer industries.

Jan 1, 1992

By J. Douglas Causey

In 1984, at the request of the Bureau of Land Management, the Bureau of Mines studied 9,600 acres of the 12,350-acre Antelope Creek Wilderness Study Area (MT-065-266) in order to evaluate its mineral resources. Within this report, these 9,600 acres are referred to as the study area. The Antelope Creek Wilderness Study Area, Phillips County, MT, adjoins the north end of the Charles M. Russell Wildlife Refuge. Considered part of the Missouri River Breaks, the area straddles the edge of a thrust fault zone that has deformed the Mesozoic strata in the west half of the area. Shale, siltstone, and sandstone of Cretaceous Age are exposed in the area. Coal beds averaging 3.0 ft thick occur in the Judith River Formation. About 0.20 million short tons of coal were mined from the Judith River Formation adjacent to the west boundary of the area; no production is known in the study area.

Jan 1, 1986

By M. J. Sapko

A moderately scaled apparatus was developed by the Bureau of Mines to determine the fire resistance characteristics of mine conveyor belts and similar type materials. The design of the apparatus was based upon data obtained in full-scale fire tests and features a radiant panel to preheat the belt and a methane-oxygen ribbon burner to ignite the sample under ventilating condi¬tions in a rectangular duct. The test method overcomes the limitations of existing laboratory-scale methods and provides a measure of both ignitability and flammability in quantitative terms. Flame propagation depended upon such variables as air velocity, ignitor heat flux, and belt width and height in the test chamber. Data are presented for nine belt materials and fire resistance ratings are proposed in terms of the flame spread rate, heat release rate, and the critical ignitor heat flux. The ratings discriminate between the fire hazard posed by different fire-resistant belts and tend to be in reasonable agreement with those obtained in full-scale fire tests.

Jan 1, 1981

By J. R. Thoenen

In the summer of 1937 the authors began a series of time studies of the various processes employed in' the production of crushed stone. These studies, made at quarries situated in the eastern and southeastern parts of the United States, have not been completed, but to make results available to the industry as early as possible, it was decided to publish summaries of the studies made to January 1, 1939, as a series of progress reports. The first of these dealt with power-shovel loading and was issued as Report of Investigations 3461 in September 1939. The second, issued in September 1939 as Report of Investigations 3467, dealt with quarry haulage. The present report discusses analyses of time studies of primary drilling at the same group of quarries. OBJECT Or STUDY Pressure of business problems frequently requires the entire attention of quarry management, and in consequence internal plant economies often are neglected. Also, operating officials absorbed in their local problems are prone to overlook possible economies that would attract attention immediately were they critically examining another plant. The authors felt that technical studies at a number of plants, made by impartial engineers, might disclose opportunities to reduce costs or improve efficiency in internal plant processes.

Jan 1, 1940

To be able to continuously monitor the noise to which underground workers are exposed as a better way to help prevent hearing damage. The Approach: The Bureau of Mines has developed a Time-Resolved Audio Dosimeter which can be worn by miners to record noise level every 30 seconds and store It in a miniature solid state memory. Figure 1 is a photo of the dosimeter. [ ] How It Works: Acoustical noise is picked up by a micro-phone and fed to a sound level meter which produces a d-c voltage proportional to the A-weighted sound pressure level. (As specified by federal regulations, the A-weighted sound pres-sure level approximates the response of the ear by discounting the higher and lower frequency components of the noise.) This d-c voltage controls an oscillator which, together with related circuitry, produces a pulse train having a frequency that's proportional to the noise level.

Jan 1, 1975

By E. D. Gradner

During 1924 a number of lives were lost and other men incapacitated by the toxic effects of gases produced in blasting in massive sulphides. In one mine, three men working in a raise were caught by gases from blasting a drift round in massive sulphide on the level. The round in the drift was shot ahead of time and it was necessary for the three men to travel through the gases to the intake air course. Two of the men lost their lives, and the third was injured, apparently for life. Other men at this same mine have been caught in the gases at blasting time and seriously injured. At a second mine, the gases from blasting in sulphides appear to be very dangerous, and it was necessary to send a number of men who were caught in such gases to the hospital. One man who was seriously gassed has not recovered in over a year is time. Another man similarly gassed soon died of influenza.

Jan 1, 1926

By Terry S. Cory

This report covers magnetic field strength measurements vs range and frequency in low-medium coal mines. Both quasi-conductor-free and conductor-proximity areas were investigated. The program covered 5 mines, 4 seams, 6 measurement sets, and 3 geographic areas. The results have been summarized in terms of maximum communication range expected per seam and noise condition. Scatter gain is further explored as a simple measure of energy coupled to conductors.

Jan 6, 1978

By Harry R. Nicholls

Six different chemical explosives were detonated in a test series to com-pare their relative performance in granite. From 5 to 255 feet from the detonation point, strain, acceleration, and particle velocity were recorded and analyzed for amplitude and pulse shape. Strain energy was calculated from strain data, and displacement data were obtained from particle velocity data by integration. The results show that explosives which have a characteristic impedance more closely matching that of the rock generate larger peak amplitudes than explosives with a lower characteristic impedance. The results also show that as the ratio of characteristic impedance of exp1osive-to-rock approaches unity, more rock is crushed and a larger percentage of the avail-able explosive energy is transferred to the rock as seismic energy. The effect of characteristic impedance is shown to be greater than the effect predicted from acoustic theory and is believed to be indicative of shock wave effects at the explosive-rock boundary.

Jan 1, 1965

By Richard A. Watson, James A. Powell

A seismic system which utilizes in-mine geophones to detect trapped miners has been developed. Tests at the Bureau of Mines Safety Research Mine at Bruceton, Pa., and at two operating mines indicate such a system has a maximum detection range in excess of 1,000 feet. The system is field worthy and portable and requires less than 30 minutes to set up and check. Real-time detection is possible.

Jan 1, 1976