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By J. P. McGee

As part of a joint U.S. Atomic Energy Commission-Federal Bureau of Mines program for using nuclear energy to supply process heat, a simulated nuclear loop has been constructed to test components. This loop has been operated for more than 1,800 hours at 100 p.s.i.g. Of this period, 23 hours were at 2,500° F. and higher; 540 at 2,000° to 2,500° F.; 840 at 1,500° to 2,000° F.; 200 at 1,000° to 1,500° F.; and 260 below 1,000° F. Leakage at flanges and welds was not a serious problem. A helium-recycle system with gas temperatures of 2,300° to 2,500° F. and a static pressure of 250 p.s.i.g. appears feasible. Difficulties were encountered with the recycle compressor due to thermal distortion of the impeller and shaft. The use of sealed bearings limits compressor operation to the life of the bearings.

Jan 1, 1960

By Louis Schaffer

This report characterizes several coal Dine mobile equipment operator populations with respect to age, mine experience, machine operator experience, and training. The information is used to demonstrate a method of normalizing the injury data collected by the Mining Enforcement and Safety Administration-Health and Safety Analysis Center.

Jan 1, 1977

By BUREAU OF MINES

LIST OF PUBLICATIONS ON CERAMIC INVESTIGATIONS U.S. BUREAT OF MINES .

Jan 1, 1923

By W. W. Cutler

An oil-field drilling campaign is used in this paper to signify the spacing of the wells to be drilled as well as the drilling program, which is interpreted as the number of wells drilled in a unit of time, This has an important bearing upon the time of receiving income, as well as upon the amount of revenue obtained In periods of low prices for oil, such as the present, the margin of profit is at the best very small, and the correct determination of the drilling campaign may be the deciding factor between incurring financial loss or gain during the depressed period. General policy of the operator. Drilling should be planned by the field engineer to conform with the general policy of the operator. This policy may be one of conservation daring the early life of the property, but as mentioned later, this may result in a smaller ultimate recovery it often occurs that the market price of oil does not warrant rapid development, or it may be desirable to hold in reserve a supply of oil for a refinery. The policy may be to recover all of the oil as quickly as possible, or it may be to maintain a constant and sustained production. In any case, the operator should, outline as far as possible a definite policy, and should understand the principles underlying the recovery of oil, the influence of rapidity of drilling and effects of spacing, in order that he may obtain the oil as required with the least expenditure.

Jan 1, 1921

By Robert J. Timko, Edward D. Thimons

Sulfur hexafluoride (SF6) is an odorless, colorless, nontoxic gas that has found acceptance as a tracer gas in research on ventilation pat- terns, measurement of air leak rates, respirable dust reductions due to bagging hood modifications, and the study of airflows relating to gob boreholes. Following a short review of the SF6 sampling technique, this report describes recent Bureau of Mines projects in which SF6 was used successfully as a tracer gas, enabling researchers to acquire representative data quickly and inexpensively.

Jan 1, 1982

The objective is to provide effective training on refuge chambers for underground coal miners. This training will increase knowledge about how to teach miners to operate, transport, and inspect a refuge chamber; what to expect psychologically and physiologically inside a refuge chamber; and how to decide when to use a refuge chamber. Background During 2006?2007, several disasters occurred at U.S. underground coal mines, resulting in 28 fatalities. These disasters led to new approaches to mine safety and health, as well as new federal regulations. One new technology mandated by federal legislation is the refuge chamber. Refuge chambers are movable shelters that are either made of steel or inflate from a steel skid as a tent. They can potentially save the lives of miners during an underground mine emergency by providing breathable air, food, water, and a safe environment for up to 96 hours. Because the refuge chamber is a new technology, recommendations, information, and training products are greatly needed.

Nov 1, 2009

By W. P. Diamond, F. Garcia, J. K. Marshall

Many longwall mines rely on methane drainage to supplement traditional fan-based ventilation systems. However, the surface production facilities for methane drainage systems, including gob gas ventholes, are commonly located in remote locations, sometimes without convenient access to electrical power, and they may be monitored infrequently. The first evidence that a methane drainage system may not be operating efficiently, or not operating at all, can be an increase in methane concentrations at a return air shaft or underground where the workforce is exposed to the risk of a methane explosion. A solar powered, remote gob gas venthole monitoring and cellular telephone-based real-time data transmission system has been developed and successfully field tested by the National Institute for Occupational Safety and Health (NIOSH) to address this problem. With this system, individual methane drainage boreholes can be monitored from the mine office to determine current operational performance parameters, as well as review past data to anticipate maintenance needs and troubleshoot operational problems.

By N. F. LeJeune

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Jan 1, 1924

Synthetic dawsonite [NaAl(OH)2C03] has been prepared with crystallinity similar to that of dawsonite found in oil shale deposits of the Piceance Creek area of Colorado. Optimum experimental conditions were as follows: Na/Al atomic ratio, 43; temperature, 175° to 200° C; pCO2, 15 psig; and reaction time 5 hr. Chemical and spectrographic analysis revealed that the synthetic dawsonite was of high purity and Has essentially stoichwmetric. Similarity of the synthetic to natural dawsonite, demonstrated by X-ray diffraction, infrared spectrophotometry, and electron microscopy, suggests its suitability as a standard.

Jan 1, 1972

By Howard M. Stainer

Jan 1, 1963

By Howard M. Stainer

[Cover Page]

Jan 1, 1963

This report summarizes the results of several field tests conducted by Collins for the Bureau of Mines under contract S0122076 and contract H0232056. The field projects represent a part of Collins continuing effort on a broad study of coal mine communications. These experiments analyze the propagation characteristics of radio signals in a working coal mine environment. The intent of the program is to provide basic propagation loss characteristics by which we may evaluate various approaches to an integrated mine communications system. The goal of such a system is to satisfy both operational and emergency communications needs in the mine.

Jan 1, 1974

By Nikolaos Polysos, Holger Witthaus

INTRODUCTION The classification system for German coal mining is the result of approximately 100 years of experience in roadway development and longwall mining. It is also based on different research projects covered by national and European research programs. Over the past 30 years, more then 600,000 m of road-ways have been driven and employed for mining activities. To properly describe the German rock mass classification system, therefore, it is useful to take a look at the main geomechanical preferences and common support systems. The decision about the most effective development technique and support system is based on a synthesis of rock mass classification and geomechanical analysis. The properties of surrounding rock, the in situ stress, and the influence of mining activities in several seams at each German mine must be considered for the evaluation of the expected deformation of the roadway. The mine layout, the requirements of ventilation and fire prevention, as well as the need to maintain emergency escape routes for the miners, require that the gate roads remain usable after the passage of the longwall face in most cases. Moreover, the gate roads must be maintained despite the high stresses that are applied during longwall retreat mining. Therefore, gate road design must address a broad spectrum of potential deformation environments. In the past, when gate roads were supported solely with yielding steel arches, lithologic descriptions of the surrounding strata conditions were adequate for the dimensioning of support and the prediction of the roadway deformation. The current conditions of multiple-seam mining at depths of up to 1,700 m require combined support systems, including pattern bolting and backfilled steel arches. Rock bolt support is used for development, after which (typically 50–100 m outby the face) the steel arches are installed and backfilled with building material (concrete) in order to achieve an optimized development rate. The rock mass classification system described below was developed especially for the conditions of German hard-coal mining. It includes the stress distribution caused by multiseam workings (including crossing goaf edges of former longwalls), as well as in situ stresses due to greatdepth and the presence of tectonic faults. It is based on the evaluation of four parameters: • Geotechnical analysis of drill cores • Geotechnical observation of the development face • Geotechnical classification of tectonic structures (faults) • Standard classification derived from geotechnical assessment and evaluation of stress conditions (using numerical modeling for stress calculation) ROCK STRENGTH One of the most important input parameters for describing strata conditions is the strength of the rock. The German classification system is based on a description of lithotypes. This method has been used successfully since the 1950s and is based mainly on the uniaxial compressive strength (UCS) of the material. An evaluation of the rock strength observed in a survey of approximately 82,500 samples of rock core yielded the results shown in Figure 1. The three most common coal measure rock types are mudstone, siltstone, and sandstone. Each shows a specific mean UCS level and a different spread between the minimum and maximum values. Sandstones, in particular, have a wide spectrum of compressive strength, ranging from approximately 40 MPa to greater than 130 MPa, with an average of 85 MPa. The causes of this wide range include different sedimento-logical preconditions, facies, and digenetic processes. [ ]

Jan 5, 2007

By Leonard J. Prosser, Dennis R. Dolinar, John L. Ellenberger, Gabriel S. Esterhuizen, Anthony T. Iannacchione

The room-and-pillar mining method is used extensively in underground limestone mines in the Eastern and Midwestern U.S. The rock mass is typically a near-horizontal, bedded deposit at relatively shallow depth. A survey of 34 mines was conducted in which data on roof spans, rock mass properties and support practices were collected as part of a National Institute for Occupational Safety and Health research project into ground control in limestone mines. The average room width is 13.5 m (44 ft), accommodating large mechanized equipment. The results show that the immediate roof beam can consist of many individual layers and can contain several near-vertical joints. In spite of the room widths, the roof is naturally stable in many mines. Observed roof instabilities can generally be related to excessive horizontal stresses or unfavorable geological structures that cause block fallout or beam failure of the bedded roof rocks. The survey showed that the rock mass quality of the limestone does not vary significantly throughout the Eastern and Midwestern U.S. Roof conditions and the need for support were found to be closely related to the thickness and competence of the first layer of limestone in the roof. The findings highlight the need to identify local geological structures and the roof beam characteristics so that support alternatives can be evaluated. Monitoring and observational technologies that are available for identifying potentially unstable roof are presented, which include: roof characterization using the Rock Fall Risk Index, automated logging of roofbolt hole drilling, microseismic monitoring and displacement monitoring.

Four catalytic converters for diesel exhaust systems were tested to determine their effectiveness in reducing the amount of harmful substances discharged into the air. Tests were conducted with four different catalytic converter designs, using two diesel engines as exhaust gas generators. (Of the four noble metal catalytic converters, three are commercially available.) Testing showed that the catalysts varied widely in oxidation efficiency at light to intermediate engine loads, but that all were very effective in reducing emissions of CO, HC, aldehydes, and odor intensity at heavy loads (engine operating modes resulting in high exhaust temperatures). Particulate loading, particulate size, and NOx emissions were generally unaffected by any of the catalysts. The catalysts had one ad-verse effect on exhaust quality--increased sulfate emissions. Because of the potential problem of sulfate emissions, the exclusive use of catalytic reactors for emissions reduction does not appear to be satisfactory. However, when used with a means for subsequent removal of sulfates, a catalyst can function as a key component in an emissions control system for diesel engines operated in underground mines.

Jan 1, 1978

By Howard W. Wainwright

The Bureau of Mines is engaged in a research program on the characterization of tars produced by low-temperature carbonization of coal and their economical upgrading to more valuable materials, Throughout the years, hydrogenation has played an important role in the treatment of these tars, mainly as a means of converting the whole crude tar or selected fractions to motor fuels; diesel oil, lubricating oil, or various solvents. In some instances, production of specialty chemicals has been the objective. The purpose of this report is to summarize, without critical review, the information of the past 25 years on the hydrogenation of low-temperature tars and related substances as presented in the literature or its English translation. Published articles and patents not abstracted in the main body of this report are included in a bibliography at the end. HYDROGENATION REACTIONS The hydrogenation of tar follows three general types of reactions; 1. The removal of oxygen, sulfur, and nitrogen in the tar to form water, hydrogen sulfide, and ammonia, respectively: [ ]

Jan 1, 1961

By Wesley A. Grosh

The Valzinco mine, Spotsylvania County, Va., is a lead-zinc deposit with minor quantities of copper. The property was reopened n 1942 by Panaminas, Inc. The Bureau of. Mines, in an effort to increase the reserves of the deposit to justify greater production, diamond-drilled nine holes totaling 4,213 feet during 1943. Drilling by the Bureau delimited the original ore body and discovered another ore body on the hanging-wall side, which was being developed by the company at the close of the project.

Jan 1, 1949

By George A. Morgan

There was little change in the mineral industry of Benin in 1986, as the economy remained in the grip of a regional recession exacerbated by failing oil prices, which nullified much of the income from Benin's oil production. Benin's industrial sector accounted for less than 10% of the gross domestic product (GDP), with the mineral industry providing about one-half of that total. Several major projects initiated over the last several years continued to perform and/or progress below Government expectations. These included the Save sugar refinery, the Dassa-Parakou section of the Dassa-Cotonou highway, the Benin-Togo Nangbeto hydroelectric plant, the Onigbolo cement plant, and the Semé Oilfield. Funding for these projects is the major source of the Beninese external debt, which was estimated to be over $800 million.2

Jan 1, 1988

By R. Ward Stahl

Fire has been one of man's most useful tools through the ages and certainly is a "must" for industrial progress but when uncontrolled is one of the most destructive agencies. This fact is even more important in a coal mine, where many persons and much expensive equipment are confined in a relatively small area. Means of escape from a burning area, as well as from the products of combustion, are often limited; and in many instances the entire surroundings are combustible. Numerous mine fires, which resulted in a high death toll and great financial loss through the years, have caused mine owners to search for the best fire-fighting equipment; much of this has been installed, the quantity depending largely upon the experience of the individual companies or neighboring mines in certain coalfields. A mine owner or operator has meager published information on the actual fire protection afforded and systems of fire-fighting inaugurated in the coalfields, by which he could compare his efforts and get some idea of the adequacy of his own protection. To further general knowledge of the subject, it was decided to survey a representative number of mines in the field and show what has been accomplished. Representative mines were selected in various coal beds; some had similar tonnage, so comparison could be made if desired.

Jan 1, 1957

By R. M. Santmayers

[This paper presents one of a series of digests of foreign mining legislation that is being prepared in advance of a general report relative to the rights of American citizens to explore for minerals and to own and operate mines in various foreign countries. This interpretation of the mining legislation of Bulgaria was prepared from a copy (in French) of the Mining Laws of Bulgaria, promulgated by Royal Decree No. 33 of I. arch. 31, 1910, and published in the "Journal Official," No. 83, April 14, 1910, and checked against a digest prepared by Maynard B. Barnes, First Secretary, American Legation, Sofia, Bulgaria, dated June 10, 1932, which was transmitted through the courtesy of the Department of State. CLASSIFICATION OF MINERAL SUBSTANCES Mineral deposits are classed either as mines or quarries. (Art. l.) Tunes are deposits, the products from which must be processed. Under this class specific mention is made of the metals (gold, silver, copper, lead, zinc, iron, chrome, titanium manganese, tungsten, tin, mercury, platinum, cobalt, nickel, cadmium, aluminum, molybdenum, bismith, uranium, antimony, arsenic), sulphur and other "analogous" mineral substances, phosphate rock, iron pyrites, sulphates, saltpeter, alum, boracic acid and its compounds, talc, asbestos, amber, graphite, merschaum and precious stories of all kinds, reek salt and other salt, peat, coal, petroleum, ozocerite, asphalt and all other bituminous substances. (Art. 2.)]

Jan 1, 1933