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By A. J. Barry

Five makes of expansion-type shells and two types of bolts (mild-steel and high-strength) were used in 30 tests made in sandstone and shale roof, The results show that the anchorage obtained in both the sandstone and shale were stronger than either type of bolt. That is, the yield loads of both bolt types were exceeded before excessive anchor slip occurred. A relationship for evaluating the anchorage effectiveness of 3/8-inch-diameter, expansion-type bolts is presented. A comparison of test results indicates that the anchorage effectiveness of 5/8-inch- and 3/4-inch-diameter expansion-type bolts did not differ appreciably.

Jan 1, 1957

By Clarence O. Babcock

ROCK BEHAVIOR has proved of national interest in a variety of fields. The behavior of rock consequent to a nuclear blast was used to detect such blasts, as criteria for the design of underground military defense installations that would resist nuclear blasts, and for judging the feasibility for peaceful uses of nuclear explosives. An obvious peaceful application of nuclear explosives would be for large-scale rock excavation, and plans were presented during the year to improve the present Panama Canal or create a new canal by this method. These plans were based largely on earlier crater tests that demonstrated rock behavior when subjected to a buried nuclear blast. A knowledge of rock behavior under impact was used to evaluate the materials of the moon by means of the geometric configurations visible in the close-up pictures of the moon surface taken by the U.S. rocket Ranger 7. The composition of the moon must be considered in devising methods for taking samples of the surface layers or in designing underground shelters as bases for future explorations of the moon.

Jan 1, 1965

By Robert P. Vinson

This report describes three coal mine ventilation studies by the Bureau of Mines in which sulfur hexafluoride (SF6) was used as a tracer gas. One of these studies was conducted to determine air movement and leakage in a sealed area. Another was run to determine the ventilation efficiency of a bleeder system. Finally, a study was made of air leakage across permanent stoppings of parallel intake airways. These studies proved sulfur hexafluoride to be a useful addition to the equipment commonly used in coal mine ventilation analysis.

Jan 1, 1976

By James E. Hill

The Bureau of Mines has been carrying on an extensive diamond- drilling program during the past 7 years on deposits of strategic and critical minerals . Often the project reports and the drill-hole logs describe the findings only in terms of the mineral being sought at the time . Then , too , results may not always be interpreted alike by several mining engineers , and the cores therefore provide a permanent tangible record to complement the project reports . The cores from projects in the eastern divisions are being stored at the Mount Weather Testing Adit . Core from a representative hole ( or skeletonized sections from several holes , if these are more representative ) is selected at each project and shipped to Mount Weather for permanent storage . At the Testing Adit an underground room was prepared and storage racks were installed . Wooden core trays designed to accommodate cores of various sizes were purchased .

Apr 1, 1947

By D. E. Seizinger

Analytical methods for oxygenates in exhaust gases were studied, and emissions of these compounds from automotive engines were measured with and without an oxidation catalyst in the exhaust system. Hydrocarbons, simple mixtures of hydrocarbons, and a single gasoline were used as fuels. With the more complex gasoline, successful analysis was possible only with exhaust from the catalytic system which preferentially converted and thus removed interfering hydrocarbon species. However, it was shown that an estimate of the oxygenate yield from gasoline used in a noncatalytic system can be synthesized from data obtained with simple fuels. Such synthesized data were used for comparison of noncatalytic with catalytic systems. Compared with those of previous studies, results of this work indicate that the action of the catalyst introduced no new oxygenates and reduced both the carbonyl and the total of oxygenates. It is concluded that the compositional character and class distribution of oxygenates in exhaust from catalytic systems may differ significantly from the composition and distribution for oxygenates not subjected to catalytic conversion. The findings also support previous estimates that noncarbonyls may constitute a significant fraction of exhaust oxygenates and may warrant attention in procedures for measurement of the oxygenates.

Jan 1, 1973

By Michael J. Sapko, Eugene M. Bazala, Eric S. Weiss, Kenneth L. Cashdollar

The data presented in this report are the results, to date, of an ongoing Pittsburgh Research Center Disaster5Prevention research program on the explosion hazards associated with blasting operations in noncoal mines. Laboratory and experimental mine tests have shown that oil shale and sulfide ore dusts can be ignited given the proper predispersed dust concentrations, particle size, and kerogen or sulfur content. Methane (CH) gas may also4be present in deep oil shale formations and can pose a significant added hazard to underground blasting operations. The most common explosive used for blasting in oil shale had been ANFO, a combination of ammonium nitrate and fuel oil; blasting in sulfide ore had used ANFO and/or dynamites. Tests conducted at the cannon gallery at Lake Lynn Laboratory near Fair chance, Fayette County, PA, provided a means of evaluating the relative incendivity characteristics of new and existing explosive products. Three explosives—a pumpable emulsion-ANFO blend, a packaged water gel, and an emulsion blasting agent—exhibited low-incendive qualities compared with other more highly incendive products such as ANFO and some dynamites. Based on the data collected during numerous full-scale blasts in oil shale and sulfide ore mines, the low-incendive products significantly reduced or eliminated the ignition hazards while at the same time providing effective fragmentation of the rock. Based on the positive results from the gallery and field testing, low-incendive explosives, coupled with good blasting procedures, show promise in reducing dust and/or gas ignitions associated with blasting operations in oil shale and sulfide ore mining applications.

By Kenneth M. Earl

In its program of investigation of deposits of strategic minerals, the Bureau of Mines did some development drilling at the Tapley deposit in an endeavor to find an additional source of copper. There are accounts that many years ago the property had some production; there are several old, inaccessible shafts apparently sunk on a vein in rhyolite or diabase. The waste dumps of these shafts contain considerable sulfides, chiefly pyrite and chalcopyrite. To cut the vein below the old mine workings, the Bureau of Mines? diamond-drilled five holes aggregating 1,204 feet. No significant copper mineralization was found.

Jan 1, 1950

By A. Wahab Khair

"This paper deals with the description of the capabilities of a unique rotary coal cutting simulator which has been designed and fabricated at West Virginia University. It operates under the simulated mining conditions with in-situ stresses (horizontal and vertical stresses) being applied to a coal block of 18 in. x 15 in . x 6 in located in a suitably designed confining chamber. Cutting drum rotation can be varied from 1 to 40 rpm with the capability of stopping the drum after a predetermined number of rotations. Tests can be performed with four different bit angles, 15, 30, 45 and 60 degrees . A maximum of seven bits could be used in seven different orbits. Various cutting depths up to a maximum of 4 in. is possible.Monitoring devices constitute, Linear Variable Differential Transformers (LVDTs), pressure transducers, cascade Impactors, flow meters, flow controls and drum cutting speed. LVDTs are used to monitor the displacement of the coal block as well as the depth of cut. Pressure transducers are used to monitor the changes in pressure, both due to the thrust and due, to the intermittent cutting nature of the rotary cutting. Flow controls will be used to run the drum at a set rpm between 1 and 40 and to provide a different rate of advance. All the above mentioned devices can be operated and monitored by a fully automated control system. Six-stage cascade impactors are used to determine the mass distribution of dust along the rotation path of the drum. The fracture size, shape and Intensity can be studied by optical microscopy and the dust entrainment by using high speed photography.This equipment will basically be used to study the fracture mechanism in coal, associated with operating and in-situ parameters and further relate It to dust generation and entrainment In underground coal mines."

Jan 1, 1988

By R. D. Currie

Many coal companies have a system for checking men into and out of the mine , and generally such systems appear to be perfectly sound and adequate . However , when the real test comes at the time of a mine disaster , too often the system is found to have failed , and hours and sometimes days pass before it is known how many men are in the mine and who they are . Most of the systems in use , when properly maintained , are adequate for the routine work of the mine , and some of them may prove adequate at the time of a mine disaster . All systems , however , depend upon proper supervision and strict adherence to the system .

Jun 1, 1930

By Irven A. Jacobson

The thermal reactions of l-methylindole were studied in the temperature range of 525° to 627° C in a flow reactor. The major products consisted of 2-methylindole, 3-methylindole, indole, quinoline, hydrogen, and methane. 2-Methylindole is formed from 1-methylindole by an irreversible isomerization reaction. The 2-methylindole isomerizes in a reversible manner to 3-methyl-indole, the equilibrium favoring the 3-methyl isomer. Indole is formed directly from 1-methylindole. Quinoline is formed from l-methylindole, 2-methylindole, and 3-methylindole.

Jan 1, 1971

By C. Özgen Karacan

Methane emissions from a longwall ventilation system are an important indicator of how much methane a particular mine is producing and how much air should be provided to keep the methane levels under statutory limits. Knowing the amount of ventilation methane emission is also important for environmental considerations and for identifying opportunities to capture and utilize the methane for energy production. Prediction of methane emissions before mining is difficult since it depends on a number of geological, geographical, and operational factors. This study proposes a principle component analysis (PCA) and artificial neural network (ANN)-based approach to predict the ventilation methane emission rates of U.S. longwall mines. Ventilation emission data obtained from 63 longwall mines in 10 states for the years between 1985 and 2005 were combined with corresponding coalbed properties, geographical information, and longwall operation parameters. The compiled database resulted in 17 parameters that potentially impacted emissions. PCA was used to determine those variables that most influenced ventilation emissions and were considered for further predictive modeling using ANN. Different combinations of variables in the data set and network structures were used for network training and testing to achieve minimum mean square errors and high correlations between measurements and predictions. The resultant ANN model using nine main input variables was superior to multilinear and second-order non-linear models for predicting the new data. The ANN model predicted methane emissions with high accuracy. It is concluded that the model can be used as a predictive tool since it includes those factors that influence longwall ventilation emission rates.

Active and abandoned mine sites can be an irresistible- - and sometimes deadly - - draw for outdoor enthusiasts, particularly children and young adults. Despite repeated warnings, posted signs, and fencing, tragedies involving accidents on active and abandoned mine property continue to make headlines, especially with the arrival of warmer weather and the summer months ahead. Over the last few years, there have been dozens of tragic incidents involving children and adults ventur­ing onto active and abandoned mine property. They include: A 16-year-old youth suffered fatal injuries after his all-terrain vehicle became airborne in an accident at a gravel mine near Albany, New York. A young boy was electrocuted when he contacted a high-voltage power line while sliding down a stockpile at a sand and gravel mine in Grand Island, Nebraska during its off-shift hours.

Jan 1, 1999

By Joseph Cervik

Gas occurs in coalbeds in an adsorbed and a free gas state, Adsorbed gas is stored in the micropore structure and its transport is governed by Fick's law. The free gas occurs in the. fracture system and flows according to Darcy's law. These two modes of mass transport are interdependent. Production decline curves of coal-gas wells are of the constant percentage decline type and, thus, show no indications of flow characteristics peculiar to coal-gas reservoirs. The effectiveness of surface boreholes as a degasification scheme depends upon both good fracture permeability and a high fracture density. Conventional methods of reservoir engineering analysis are not applicable to coalbeds.

Jan 1, 1969

By Larry G. Stolarczyk

1.0 FRAMEWORK FOR COMPARISON This document describes the decision factors that bear on the selection of the modulation process for the wireless underground medium frequency (MF) communication system. The selected modulation process must satisfy the Bureau of Mines stated objective of improving general communications within an underground mine. The improvement being sought includes the development of a wireless communication technology of measurable benefit to both mine safety and mine productivity. The improvement will allow wireless communications paths to exist between roving miners. The wireless communication paths will also be made compatible with the existing underground telephone system to extend paging and voice communication throughout the underground mine. The new wireless equipment will include man-pack, vehicular, repeater, and base station transceivers. Repeaters and base stations will feature coupling networks for interfacing with the existing telephone circuits. Frequency modulation (FM) and single sideband (SSB) modulation processes are analyzed in view of the special conditions associated with underground mining. Of primary importance is the tremendous electrical noise generated in an operating mine that could adversely affect communications quality. High noise coupled with high attenuation rate of near field signals forces the communication system to be inherently short range. Fortunately, near field signals can propagate over great distances on underground wires and cables. The framework for comparison is generated by presenting all factors that

By T. M. Barczak

Many of the support concepts currently used in the United States originated in South Africa. These products include the Hercules Crib1, Propsetter, MX Prop, Rocprop, and Spider Prop. Another recent development has been the introduction of hydraulic prestressing units, such as the Jackpot system, to various U.S. standing support systems. Several other prop-type supports with similarities to systems used in South Africa are in use in U.S. coal mines. Some exciting new developments that improve the installation and yield performance of props are also underway. In addition to prop-type supports, crib-type supports and single-unit systems such as the Can support are also frequently utilized in longwall tailgates in the U.S. The goal in U.S. support development is to enhance roof support capability while alleviating material handling barriers to reduce injuries associated with support handling and installation. Support products are generally full-scale tested at the National Institute for Occupational Safety and Health (NIOSH) in the unique Mine Roof Simulator load frame. The performance testing protocol is designed to simulate the full range of load conditions that occur in underground mining to identify the performance deficiencies and limitations of the support products. Once the products complete the performance evaluation, they are implemented into the NIOSH Support Technology Optimization Program (STOP). STOP is a window’s based software program that was developed by NIOSH for facilitating the design of standing roof support systems. STOP has become an industry standard to compare the performance capabilities and facilitate the application of these support products into various mining conditions. The purpose of this paper is to provide an overview of the support design and application philosophy in the United States.

By A. Visnapuu

High-grade synthetic rutile has been produced in the laboratory from domestic ilmenite concentrates by a new carbonyl process. The ilmenite was first reduced to convert the iron oxides to metal and then treated at temper-atures over 1000 C in high-pressure carbon monoxide (CO) to convert the iron to the pentacarbonyl. Rapid carbonylation was achieved in the presence of small quantities of selected promoters. Maximum iron removal occurred at temperatures between 110° and 130° C at CO pressures from 1,000 to 1,400 psig. Iron pentacarbonyl appeared as liquid and vapor in the reactor and could be removed by gravity flow and vapor transport. More than 90 pct of the iron was extracted in 2-hr experiments at pressures of 1,000 psig and above. The Ti02 product is porous owing to the removal of the iron, has the rutile crystal structure, and is suitable for chlorination. Waste disposal problems associated with the process would be minimal because the iron pentacarbonyl can be decomposed to produce iron powder or pellets for sale and CO for recycling.

Jan 1, 1973

By A. B. Cecala

A cooperative research effort was established between the Tilden Mining Company LC, the United Steelworkers of America, and the National Institute for Occupational Safety and Health to lower respirable dust levels in an iron ore grinding and concentrator plant. This cooperative effort involved three field studies to evaluate different techniques to lower respirable dust levels. The greatest impact on lowering respirable dust concentrations throughout this facility was achieved through ventilation changes. The most significant improvement was realized by changing the ventilation profile throughout the entire facility. The ventilation to this grinding and concentrator facility was provided by approximately 40 roof fans operating in either the intake or exhaust mode. The operation of these fans was significantly changed in an attempt to pro-vide more of a directional flow pattern throughout the facility, as well as to more closely balance the intake and exhaust air volume. This change accounted for a 31 pct reduction in respirable dust levels in the primary grinding area of the mill. Another successful modification was to improve the sealing of a reclaim tunnel to the outside and by barricading the access point from the reclaim tunnel to the concentrator plant. This minimized the dust liberated in the conveyor tunnels from traveling through the reclaim tunnel and into the plant. These two modifications illustrate the impact that improvements in ventilation can have on lowering respirable dust concentrations in iron ore processing facilities.

By A. A. Giardini

This report represents the results of a literature study on boron nitride and related substances. The purpose of the study was to find Information that might be of value for production of a new, hard modification of boron nitride preferably in single crystal form. The report consists of a review of the major developments in boron nitride research, a discussion of the results, tabulations of physical and chemical properties;, conclusions drawn from the study, and a bibliography.

Jan 1, 1953

By E. J. Kloos

The Bureau of Mines developed a test for evaluating gas masks designed to protect against phosphine gas; phosphonium iodide is used as a source of phosphine. Gas masks approved by the Bureau for respiratory protection against phosphine include the GMC-SS-1, Mine Safety Appliances Co.; the LG-10 and LG-10G, Willson Products Division, The Electric Storage Battery Co.; and the 084-PHOV-R, Acme Protection Equipment Co.

Jan 1, 1966

By Rose L. Ballard

This chapter summarizes data on crude nonfuel mineral production for the United States, its island possessions, and the Commonwealth of Puerto Rico. Included also are tables that show the principal nonfuel mineral commodities exported from and imported into the United States, and that compare world and U.S. mineral production. The detailed data from which these tables were derived are contained in the individual commodity chapters of volume I and in the State chapters of volume II of this edition of the Minerals Yearbook. Although crude mineral production may be measured at any of several stages of extraction and processing, the stage of measurement used in this chapter is what is normally termed "mine output." It usually refers to minerals or ores in the form in which they are first extracted from the ground, but customarily includes the output from auxiliary processing at or near the mines. Because of inadequacies in the statistics available, some series deviate from the foregoing definition. For gold, silver, copper, lead, zinc, and tin, the quantities are recorded on a mine basis (as the recoverable content of ore sold or treated). However, the values assigned to these quantities are based on the average selling price of refined metal, not the mine value. Mercury is measured as recovered metal and valued at the average New York price for the metal.

Jan 1, 1981