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By R. W. Stahl

Burning coal-mine refuse banks were surveyed in 15 States. The following characteristics were tabulated for 495 hanks: County; name, population, and distance of nearest town; size and status of bank; status and stage of fire; and topography. Ways of controlling fires were reviewed, the compacting and sealing method proving most satisfactory. Means for preventing refuse-bank fires by proper construction of banks are described.

Jan 1, 1964

By David Bendersky

This report covers a technical and economic investigation of old electrical power systems, equipment and practices being used in the metal/non-metal raining industry. The principal sources of information were the MSHA District offices, visits to representa¬tive mines and mills, equipment manufacturers and the literature. A list of 85 mines and mills, submitted by the MSHA Districts as candidates for this study, is given and their characteristics are analysed. The electrical power systems and practices at the 10 mines and 9 mills which were visited are described. The principal areas which do not conform to standard electrical practices are discussed with emphasis on the safety aspects of these practices. The costs to update electrical power systems and practices in metal/non-metal mines and mills are given. The principal findings of the study are summarized and recommendations are submitted.

Jan 1, 1980

By C. Ogasawara

This document describes the direction and progress of the Bureau of Mines Oil Shale Mining Environmental Research Program as of January 31, 1979. It is aimed at focusing the Bureau's role in environmental research supporting oil shale development with respect to the activities of other involved government agencies and private industry. Environmental considerations in oil shale extraction, such as ecological disturbances, health and safety hazards, waste management, and socioeconomic impacts, are discussed along with the type of research known to be planned by organizations to ameliorate these problems.

Jan 1, 1979

By W. R. Crank

[Rock bursts are phenomena associated with mining operations, particularly with deep mining, although they occur throughout a wide rump, of depth, from 600 feel downward. The intensity is usually in direct proportion to the depth, varying from a loosening and sloughing off to a violent rupture, giving rise to the term, "explosive rock." The more or less violent breaking of rock in mine working, tins been variously designated as " flaking," "pressure hoists," "strain bursts," "bumps," "quakes," and "air blasts," which indicate opinions as to cause and effect. The term "air blast" lots probably beat most widely used, and naturally so, as a more or less rapid movement of air often accompanying the more violent phenomena of rock failure. Furthermore, there is an implied if not definitely expressed degree of magnitude in the action designited by a given term and in the cause and character of the action. For example. flaking, pressure bursts, and quakes are terms ranged to indicate action of increasing magnitude; and pressure bursts, strain bursts. bumps, and quakes are ranged according to the cause and character of the action.]

Jan 1, 1929

By A. T. Iannacchione

Underground limestone mines typically use the room-and-pillar method of mining in the generally flat-lying limestone formations. In some cases the dip may exceed 5° which can result in unique roof instability problems. Stability may be further exacerbated by the presence of horizontal tectonic stresses. Field studies and numerical model analyses are combined to assess the affect of the dip in various stress conditions. The results showed that where the horizontal tectonic stresses are sufficient to cause intact rock failure, increasing dip results in increased failure potential. The effect of the dip is greater when the maximum horizontal stress is parallel to the dip. Two case studies are presented and evaluated against the findings of stress analysis results. The study showed that the empirical rules of orienting headings parallel to the maximum stress are generally applicable to dipping excavations, except when mining in the up-dip direction. The importance of accurately determining the orientation of the maximum horizontal stress is emphasized because the window of favorable orientations relative to the stress is small.

By Mark I. Copeland

The Bureau of Mines investigated the effect of up to 1 wt-pct of copper and silicon on the heat treatment response and hardness, tensile, and impact properties of hot-rolled medium-carbon steels. The steels were prepared by induction melting and fabricated into plates by forging and rolling. The tensile strength of 0.2-wt-pct carbon steels containing 0.3 wt-pct silicon was affected significantly by copper in both the hot-rolled and heat-treated (600° C) conditions, whereas the tensile strength of the 0.3-wt-pct carbon steels was less affected. A 600° C treatment was considered optimum as a post-rolling treatment to strengthen the steels by copper precipitation. Strengthening of 0.2-wt-pct carbon steels by silicon was reduced by increasing copper contents.. Optimum impact strengths occurred at about 0.3 wt-pct silicon in 0.2-wt-pct carbon steels containing 0.6 and 0.8 wt-pct copper. The impact strengths were lowest for 0.2-wt-pct carbon steels containing over 0.8 wt-pct copper and greater than 0.3 wt-pct silicon, especially in the heat-treated condition. Copper and silicon solutes and copper precipitates strengthened the steels. This effect was augmented slightly by strengthening through grain refinement by these solutes.

Jan 1, 1973

By P. M. Daling

This report, sponsored by the U.S. Bureau of mines, presents the results of an examination of available safety assessment methods and their applicability to the mining industry. Standard safety analysis procedures were evaluated for relevance to the mining industry and mire operators' needs. The major safety concerns and needs of mine operators were identified through telephone contacts and a visit to a mine site. Safety assessment methods recommended for use by the mining Industry were also investigated for potential adaptability to a user-interactive computer system. Several methods were determined to be Immediately transferrable to the mining industry; these techniques are described in a user's handbook produced as part of this project. The handbook gives detailed instructions on appropriate application and utilization of these methods. Other techniques will require further development before they can be effectively transferred to the mining Industry. These methods, their advantages, disadvantages and resource requirements are described in the final project report. Recommended system safety analysis techniques facilitate an evaluation of total mine system safety and a determination of safety-related interactions among systems within a mine. The application of these methods to the mining industry could result In reductions in both the frequency and the consequences of mine accidents.

Jan 1, 1983

By Robert Stefanko

In the context of the following report, an hazardous location can be described as any industrial area in which flammable or explosive gases, vapors, and dusts can be encountered. When electrical apparatus is used in such hazardous atmospheres, the chance of a dust or gas ignition is ever present. Consequently, in an effort to reduce the ignition hazard, several protection systems have been devised. Such systems are termed electrical hazard reduction techniques. The most widely accepted and used of these, the explosion-proof enclosure, is the principal subject of this report. However, other techniques are briefly mentioned. Hazard reduction techniques used in coal mine atmospheres (which can contain methane, coal dust, and air mixtures) are classified as Group I. The explosion-proof enclosure commonly used in mines is defined by the USBM Schedule 2G as a device that can contain internal explosions of methane-air mixtures without undergoing damage or excessive distortion and without an ignition of a surrounding methane-air mixture or discharge of flame. (100) Internationally, the definition remains the same except the words "discharge of flame" are not present. (4,5,31,42,52,76,102) The latter description often refers to flame-proof enclosure construction, but the terms "flameproof: and "explosion-proof" commonly have the same connotation. These enclosures which may not be vapor tight, are distinguished by heavy-wall cast or welded construction and bolted or threaded close fitting flanges.

Jan 1, 1974

By Donald R. Johnson

Apparatus providing simultaneous differential thermal analysis, thermo-gravimetry, and evolved gas analysis, has been developed by the Bureau of Mines specifically for thermal study of oil shale and other solid, natural fuels. The apparatus is described in detail, and simultaneous analyses on a single sample of an oil shale mineral, nahcolite, and a thermal analysis demonstration compound, calcium oxalate monohydrate, are presented to demonstrate the instrument's capabilities.

Jan 1, 1970

This report presents the results of a study of Kennecott Copper Corporation?s Chino leaching dump at Santa Rita, N. Mex. The stability studies described herein were performed on only one cross section of the leach dump, utilizing data obtained from drilling, sampling, and testing, which was limited in nature. The first part of the report contains a discussion of site geology and seismicity, pertinent information on the waste material disposal system and leaching method, a discussion of the waste embankment characteristics, a summary of the engineering analyses, and a bibliography. The second part (appendices) contains basic geologic and engineering data supporting the discussions in the first part.

Jan 1, 1974

By David E. Fogelson

One model each of three different makes of portable displacement seismographs was calibrated on a shaking table capable of 5,000 pounds of force, Calibration tests were conducted in the frequency range of 5 to 200 c.p,s, and in the amplitude range of 0,002 to 0.05 inch peak-to-peak, The seismographs were tested under two mounting conditions: (1) The feet of the instrument were bolted to the shaking table, and (2) the feet were resting on emery cloth affixed to the table, The results of these tests show that, in the frequency range of 5 to 40 c.p,s, and for vibration levels less than 0.2 g, the magnification for all three instruments is constant with input level but varies slightly with frequency. For vibration levels greater than 0.4 g. and for frequencies greater than 40 c.p.s., the magnification of all three instruments shows large variations with frequency and amplitude of table motion.

Jan 1, 1962

By A. U. Miller

"Ventilation is one of the meet important factors in mining, although until recent years less thought has probably been given to effective ventilation than to any other one phase of mining. In the past, very little, if any, attention was given air courses until they became so constricted by falls that the volume of air was greatly reduced; and, in addition, the stoppings and doors were so poorly constructed that only a very small percentage of air reached the face workings.As a matter of fact, mines have been visited where the volume of air being circulated in certain sections was much larger than in others, and where the management was striving to increase the flow of air in those sections with the least air current, believing the ventilation to be deficient. After sampling and analyzing the return air from the various sections in such mines it has been found that the quality of the air in certain places with the largest flow was more impure than in some of those with the least flow.In past years, practically all mine fans were operated by steam-driven engines supplied with steam from the mire boiler plant. No check was made on the steam consumption or the power cost of operating the fan, therefore the management had very little if any definite information as to cost of ventilating the mine.With the increased use of electrically-driven equipment in mines electricity is being used more and more to drive mine ventilating fans, and since in many instances the current is purchased from central power plants operators have come to realize that in many cases the cost of operating the fans is very high. Some engineers estimate that it ranges from 20 to 50 per cent of the total power cost of the mine. This information, together with the fact that mines are now being developed on a larger scale, requiring larger quantities of air for the men to dilute the gases liberated, has caused the large progressive companies to make, a more comprehensive study of mine ventilation, resulting in a decided improvement in the quality and quantity of air at the face workings, as well as reducing materially the ventilating costs."

Oct 1, 1930

By Walter E. Pittman

In its role of providing technical assistance to the mining industry, the Bureau of Mines' Tuscaloosa Research Center has conducted research to develop trapped miner location systems which would aid in locating miners trapped by underground mining disasters. Efforts to produce electromagnetic systems for the location of trapped miners underground and to communicate with them were surveyed, from the 1920's to 1981. Theoretical studies of through-the-earth electromagnetic transmissions are described as well as studies of the electrical characteristics of various rocks, minerals, and soil. Several trapped miner location systems are reviewed including the Westinghouse systems, the DEVELCO system, and an automated three-dimensional location system, and the phase difference of arrival technique. Tangential research, relevant to trapped miner location systems is described. A comprehensive bibliography covering all aspects of trapped miner, through-the-earth electromagnetic location and communications systems is appended.

Jan 1, 1982

By John C. Machisak

The National Safety Competition is sponsored and conducted annually by the Bureau of Mines, U.S. Department of the Interior, to give greater impetus to the building of programs safeguarding the employees of the mineral industries from disabling work injuries. The results of the 1960 National Safety Competition are presented in this publication. Mines and quarries that were awarded the Sentinels of Safety trophy for the best safety record in their competitive group and those mineral operations that ranked second, third, fourth, and fifth in the competition are listed with a summary of their achievements in preventing disabling work injuries. In addition, this publication presents statistical data on disabling work-injury experience in all other mines and quarries participating in the annual competitions.

Jan 1, 1962

By J. R. Ross

Recovery of uranium from slightly alkaline mine water, available in the Ambrosia Lake district of New Mexico, was studied using countercurrent ion exchange columns developed by the Bureau of Mines. Approximately 5 million gallons of mine water containing 9 to 12 ppm U308 was treated by ion exchange using a 14-inch-diameter absorption column composed of five or six compartments each 4 feet deep. Uranium recoveries averaged in excess of 98 percent at solution flows ranging from 15 to 25 gallons per square foot per minute and resin loadings up to 3.6 pounds of U.08 per cubic foot. In subsequent tests, loaded resin was continuously eluted in a countercurrent elution column with a diameter of 4 inches and containing a bed of resin 9 feet deep. The resin was eluted to a residual loading of less than 0.06 pound of U305 per cubic foot, at a resin-retention time of 224 minutes, using only 1.9 volumes of 1.1 M NaCl-0.05 M NaHCO3 solution per volume of resin. Compared with existing ion exchange practices for recovering uranium from mine waters in the Ambrosia Lake district of New Mexico, use of these improved ion exchange contactors would reduce ion exchange resin requirements at least 70 percent and allow further substantial reductions in capital and operating costs.

Jan 1, 1971

By Karl R. Becker

A variety of commercial detonators (fuse type and electric instantaneous and delay types) were subjected to impact and thermal stimuli to determine initiation stimulus levels and the dominant parameters in resistance to initiation. In the impact trials the detonators were impacted along their length to find the most sensitive region; threshold initiation limits obtained for these regions ranged from 3.47 to 20.82 joules (2.6 to 15.4 ft-lb). The friction sensitivity of the explosive component was an important parameter in determining sensitivity; various construction features of nonexplosive components played a role as well. In the thermal sensitivity trials, the detonators were heated from ambient to 100° C at an average rate of about 1.0° C/min, and thereafter at 0.5° C/min until they exploded; the explosion temperatures observed ranged from 121° to 188° C. These temperatures correlated quite well with the reaction temperatures of certain characteristic explosive components used by different manufacturers. The data also indicated an effect of confinement on explosion temperatures of detonators.

Jan 1, 1975

The principal activities of the Bureau of Mines Explosives Research Center during fiscal year 1969 (July 1: 1968, to June 30, 1969) are reviewed in part 1. Part 2 presents short abstracts of the publications issued during this period in the Bureau series and in the outside press. These publications are referenced in part 1 by underlined numbers in parentheses. Other publications, which are not abstracted, are cited in footnotes throughout the paper. ACKNOWLEDGEMENTS The Bureau acknowledges the support received through cooperative agreement in fiscal year 1969 from the Manufacturing Chemists Association. It also acknowledges the sponsorship by the following Government agencies of research conducted during that period: Department of the Air Force, Department of the Army, Department of Health, Education, and Welfare, Department of the Navy, Federal Aviation Administration, National Aeronautics and Space Administration, Space Nuclear Propulsion Office, and United States Coast Guard.

Jan 1, 1970

By G. E. McElroy

[The ventilation of development faces in mines for diluting gas or dust concentrations aid in hot mines for providing air-motion cooling affect, by fan-pipe units discharging high-velocity streams of air close to the face, is an important phase of mitre ventilation. The effectiveness of such units depends largely on the air-flow distribution between-the pipe discharge said the face, a subject on which little definite information is available. A study of the air, flow from grills into rooms3/ has provided sore basic data, but under conditions so different from mine fan-pipe installations in development ends that tae data to are of doubtful application to mine installa¬tions, owing to differences in air-flow conditions. The purposes of this report is to present and discuss the results of an initial series of tests of a general investigation designed to yield definite laws and design data for the discharge of fan-pine lines in nines. The s series was planned to yield preliminary data on the effects of velocity of discharge, size and shape of tripe, and adjacent calls on the air-flow distribution. Tents were made on 10-inch pine with seven different end conditions and one change of wall condition. Changes in size and shape of discharge wore made b y short transformation pieces directly at the discharge end, with the result that effects due to contraction and expansion of the flow, which proved to be of much greater importance than was expected, totally obscured any normal effects cue to size anti shape. The results of this series of tests, therefore, relate to 10-inch pipe with various discharge designs is and ago se reported.]

Jan 1, 1940

By Oliver Bowles

Sandstone, a widely distributed siliceous sedimentary rock, is the third most popular building stone in the United States. It is formed by the breaking down of preexisting rocks by weathering, subsequent segregation of the detrital quartz grains into discrete deposits by the sorting action of water or wind, and finally cementation of the quartz sand into a coherent rock. The homogeneity and resistance to weathering of the resultant sandstone make it suitable for exterior construction. Its excellent wearing properties explain its popularity for flagging and stair treads. However, quarrying and dressing methods and costs are adversely affected by the abrasiveness and hardness of sandstone especially as compared to limestone.

Jan 1, 1963

By Paul L. Campbell

Investigations by the Federal Bureau of Mines of methods of upgrading tar obtained by low-temperature carbonization of lignite showed that ß,ß?-oxydipropionitrile, ß,ß?-iminodipropionitrile, and ß,ß'-thiodipropionitrile were effective solvents for extracting aromatics (aromatic hydrocarbons plus polar compounds) from coal-tar neutral distillate fractions. Batch extraction showed that these solvents extracted approximately the same percentage of aromatics from various neutral oil fractions boiling between approximately 170° and 350° C. In continuous countercurrent extractions using oxydipropionitrile and iminodipropionitrile, approximately 30 to 35 vol.-pct, and 65 to 70 vol.-pct, of the aromatics in 170° to 350° C. neutral distillate oil were extracted at room temperature when solvent-to-oil ratios were 2:1 and 12:1, respectively. As the concentration of aromatics in the neutral distillate oil fraction decreased, the capacities and, to some extent, the selectivities of these solvents for the remaining aromatics decreased. Aromatics were isolated from the extracts and the solvents recovered by washing the extract fractions with a low-boiling paraffinic hydrocarbon such as heptane, using hydrocarbon-to-extract ratios of at least 2:1. The heptane wash removed most of the aromatics but only part of the polar compounds (compounds containing oxygen, sulfur, and nitrogen) from the extracts. The recovered oxydipropionitrile and iminodipropionitrile, containing polar compounds, were effective in extracting aromatics from neutral distillate oils. The contaminated solvents showed essentially the same capacities and selectivities as the pure solvents.

Jan 1, 1961