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By L. Douglas Smoot

This research program was a theoretical and experimental study to improve understanding of the mechanisms of flame extinguishment in methane-coal dust-air-suppressant mixtures. This final report is a summary of work conducted during this grant, sponsored by the Bureau of Mines. Work under this new grant closely followed a recently completed contract for the Bureau of Mines that was conducted at this laboratory, and results of the earlier contract are also summarized in this report, as required in the grant work statement. The experimental effort was concentrated on supplementing the limited data available to describe laminar flames in methane-coal-air-suppressant mixtures. The theoretical effort was devoted to developing a comprehensive model that could be used to explain and extrapolate the experimental data. Selected for study were the following flames: Methane-air; methane-air plus KHCO , KNO3, K C204, KBr, Al203 or Monnex; methane-coal dust-air; coal dust-air with size, volatiles content, and concentration as variables, and coal dust-air plus KHCO3, KN03, KBr, NaCl or CaC03.

Jan 1, 1978

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

Under contract from U. S. Bureau of Mines, Harza Engineering Company in cooperation with Eastern Associated Coal Corporation, conducted a ground control study of two mechanized longwall panels at the Federal Number 2 Mine. The mine is located in Northern West Virginia, and the coal is mined from the Pittsburgh Coal Seam. The prime objective of the study was to collect data which will aid in the proper selection of the longwall supports system and to control the entry caving problem. Instruments installed in the mine were borehole pressure cells, convergence recorders, roof sag recorders, horizontal roof strain indicators, differential floor movement systems, and lateral roof and floor movement systems. Instruments installed on the surface, above the instrumented longwall panels, consisted of slope indicator system, vertical bed settlement probe system and shear displacement detecting system. A comprehensive surface subsidence study was conducted in conjunction with the instrumentation. In addition to the instrumentation and monitoring, special tests were conducted to determine the bearing capacity of the roof and floor rocks, in situ modulus of coal, roof and floor rocks, and response of borehole pressure cells to ground stress. Cores of coal measure rocks were collected for the physical property tests. Face observations were made to detect various roof behavior parameters under the different jack setting pressures. This report essentially describes the instrumentation work, special tests and presents the data collected.

Jan 1, 1976

By Mulligan John J.

The Bureau of Mines investigated lode tin deposits on Potato Mountain, Seward Peninsula, Alaska. Tin was found to occur as cassiterite associated with quartz, tourmaline, pyrite, arsenopyrite, and earthy clays, but the deposits lack the varied accessory minerals commonly found in tin districts. The tin-bearing deposits are in metasediments along minor breaks and bedding planes but not in the crushed earthy filling of major faults. Cassiterite and sulfides occur with quartz in veins, both with and without earthy clays, and disseminated through tourmalinized wall rocks. The deposits are characterized by irregular segregations containing 1 to 10 percent tin within zones averaging not over 0.25 percent tin. The largest segregation exposed is on the summit of a low hill on the east-central slopes of Little Potato Mountain; most of the outcroppings are in an area trending east to west, roughly 10 to 30 feet wide and 300 feet long. Sample values ranged as high as 12 percent tin, but the average grade may be about 1 percent tin. The extreme irregularity of both grade and composition precludes a more exact determination. Similar concentrations are scattered for over 1,000 feet to the west and north, but these are smaller and lower in grade. Elsewhere on Potato Mountain, generally similar deposits occur as clusters of veinlets at widely separated points in the metasedimentary walls of major faults.

Jan 1, 1965

By O. C. Blade

Sales of diesel fuel in the United States during the post year and a half have increased greatly. In 1955 over 174 million barrels were sold of which 80 million (or 46 percent), were used by the railroads, and over 44 million barrels (25 ½ percent) of the fuel were used in trucks, busses, tractors, and heavy moving equipment. Vessels (12 percent), industry (9 ½ ), the military forces (4 ½ ), power plants (2), and oil companies (1/2 percent) account for the remainder. 2/ Dally deliveries of diesel type fuel from refineries averaged over 16,750 barrels during the first six months of 1956 in comparison with 15, 250 barrels during the corresponding period of 1955. 3/ Information on the properties of diesel fuel is very important to the petroleum industry, engine manufacturers, and consumers. To supply such information the American Petroleum Institute and the Bureau of Mines, United States Department of the Interior, under cooperative agreement, are conducting annual surveys of diesel fuel oil produced in refineries in this country.

Jan 1, 1957

By S. H. Ash

For several years considerable activity has been devoted to economic and social factors affecting California metal-mining operations as they relate to accidents and their cost. The reason for this intense interest is that accidents cost this industry annually over $1100,000 in industrial insurance premiums for mines insured by insurance carriers only; during 1924-32, inclusive, they amounted to $3,616,9115. There are several reasons for this high cost, the most important of w rich are the consistently .high frequency and severity rates of injuries occurring in the industry. Coordination of effort, appreciation of a mutual problem, and widespread education are essential if accidents and their cost are to be reduced.

Jan 1, 1935

By Wilbert J. Huff

This is the sixth of a series of annual reports describing the work of the? Explosives Division, Bureau of Mines, United States Department of the Interior.3/ It deals particularly with the activities of the division from July 1, 1940, to June 30, 1941. The studies outlined in this and preceding reports of the series have been conducted under the direction of the author and the respective unit leaders, to whom specific credit is given.

Jan 1, 1942

By Thomas E. Finch

This report is a continuation and expansion of a previous USBM grant (No. G0254004) which examined alternative methods of handling the parting between two coal seams in a surface mining operation. The alternative methods consist of equipment implementation in either a stowing or haulback technique. Following a typical strip mine conformation, the parting is directly stowed or hauled back and placed in the pit bottom after second seam removal. The objectives are to produce an environmentally sound material placement technique and to increase prime stripping machine utilization. This report contains the engineering philosophy behind two computer programs created to evaluate parting handling methods over d wide range of coal and parting thickness ratios. The nature of the computer approach allows cost sensitivity analysis and quick updating of costs. The two programs are clearly presented with documentation and examples such that consumers may apply then to their own operations.

Jan 1, 1977

By Wilbert J. Huff

This is the sixth of a series of annual reports describing the work of the Explosives Division, Bureau of Mines, United States Department of the Interior.3/ It deals particularly with the activities of the division from July 1, 1940 to June 30, 1941. The studies outlined in this and preceding reports of the series have been conducted under the direction of the author and the respective unit leaders, to whom specific credit is given.

Jan 1, 1942

By F. A. Penning

Improved skips, with lightweight cylindrical bodies, have made a significant contribution to advancing mine hoisting technology. New concept skips of aluminum bodies with rubber lining; fiberglas bodies with polyurethane liners have been designed and fabricated for field testing at an operating mine. New design, adjustable guide rollers have shown improved ride characteristics with noticeably less wear. Major reductions have been made in stress levels and stress concentrations. Field experience has shown the practicality of the approach. Guide alignment has been measured using the Guide Alignment Measuring System (GAMS). Analysis has been applied to interpret the data. Field measurements in an operating shaft and a test tower have shown the agreement in data from GAMS and plumb wires. Reproducibility has been demonstrated. The data are useful to realign shafts, to use as s maintenance tool, and to evaluate the maximum safe hoisting speeds. The surveys are made at several hundred feet per minute and the system is self-contained. Dynamics of skip-guide interaction has been analyzed using the computer program SKIP II. The effects of speed, weight, type of guides, kind of misalignment have been studied. Resonance has been demonstrated and factors that eliminate resonance have been identified. Data from the GAMS surveys are applicable to the SKIP II program. Interaction between the hoist rope and the mine conveyance has also been studied. Computer programs and closed-form solutions are presented. Economic impact of lightweight skips is presented for an existing mine and for a new mine. Reduction in rope size has a profound effect when using a lightweight skip for the same capacity. Increased productivity can be realized by keeping maximum rope pull the same while increasing skip capacity. Examples and charts project the significant savings in capital expenditure for new installations.

Jan 1, 1985

By Herbert Haas

The Bureau of Mines is endeavoring to reduce waste and increase efficiency in the production, refining, and utilization of petroleum . During the last few years the demand for petroleum and its products has increased so much more rapidly than the production that greater efficiency in utilization is now a matter of most serious importance . The Diesel engine, a comparatively new type of internal-combus- ' tion engine, is an important device for insuring more efficient utilization of petroleum and coal-tar products, for it consumes heavy liquid fuels such as can not be utilized in other types. Like the gas or the gasoline engine, it is revolutionary within its province. For some uses this engine is replacing gas and gasoline engines , but its most important duty will be to replace the wasteful consumption of fuel oil in steam engines. Not only will a wider use of the Diesel engine relieve the demand, but it will result in more power being obtained from the same consumption of fuel oils . In spite of these advantages, comparatively few Diesel engines are in use in the United States . In this report the author discusses recent developments in the design and construction of the Diesel engine, the fuels suitable for burning in it, and the uses to which it is particularly adapted .

Jan 1, 1918

By G. W. Jones

As part of its program for the promotion of safety, the Bureau of Mines has investigated various means of mitigating or eliminating the explosion hazards of combustible gases and vapors found in the mining and other industries. Knowledge as to the explosive characteristics of cyclopropane in air, oxygen, and other gaseous mixtures is of both theoretical and practical importance because cyclopropane is now used extensively in anesthesia. As such an agent it has many desirable characteristics, and increased consumption of this gas may be expected if the explosion hazards now attending its use can be minimized or eliminated. The present practice of using mixtures of approximately 20 percent cyclopropane and 80 percent oxygen should be discouraged because such mixtures are violently explosive and have led ,to fatal accidents.

Jan 1, 1940

By G. W. Jones

As part of its program for the promotion of safety, the Bureau of Mines has investigated various means of mitigating or eliminating the explosion hazards of combustible gases and vapors found in the mining and other industries. Knowledge as to the explosive characteristics of cyclopropane in air, oxygen, and other gaseous mixtures is of both theoretical and practical importance because cyclopropane is now used extensively in anesthesia. As such an agent it has many desirable characteristics, and increased consumption of this gas may be expected if the explosion hazards now attending its use can be minimized or eliminated. The present practice of using mixtures of approximately 20 percent cyclopropane and SO percent oxygen should be discouraged because such mixtures are violently explosive and have led to fatal accidents.

Jan 1, 1940

By Robert A. Harrow

This report documents the results of the development and installation of an illumination system for an underground coal mine Shortwall Mining Section. Also presented are the techniques used for the above ground test and evaluation of the lighting system prior to installation underground which resulted in the issuance of a Statement of Test and Evaluation (STE) from the Mine Safety and Health Administration, Technical Support, Beckley, West Virginia.

Jan 1, 1979

By M. I. Copeland

The investigation of the iron-gadolinium phase diagram is part of a project undertaken by the Bureau of Mines and sponsored by the Atomic Energy Commission to investigate rare-earth alloys. Data from the investigation of the iron-gadolinium phase diagram revealed a single eutectic system with very limited terminal solubility and three intermediate phases. The eutectic point occurs at about 85 percent gadolinium, and the eutectic isotherm, which occurs at 850° C., extends from the compound Fe2Gd to 99-plus percent gadolinium. Very little solubility of the solid phases in each other was observed. The three intermediate phases, FegGd, Fe3Gd, and FeaGd, melt incongruently at peritectic isotherms at 1,320°, 1,150°, and 1,080° C., respectively. The crystalline systems of the three phases were determined as follows: FegGd, hexagonal; Fe3Gd, hexagonal or rhombohedral; and FeaGd, face-centered cubic. No lowering or raising of the alpha-gamma iron transformation at 910° C., the gamma-delta iron transformation at 1,388° C., or the gadolinium transformation at 1,262° C. was observed. The principal methods used in determining the iron-gadolinium phase diagram were melting-point determinations, thermal analyses, metallographic examination, and X-ray diffraction analyses. Melting, heat treating, and thermal analyses were conducted in a vacuum or under a helium atmosphere because of the avidity with which oxygen combines with gadolinium at elevated temperatures. A few hardness values were determined, but they had no part in the derivation of the phase diagram. No other mechanical properties were determined.

Jan 1, 1962

By Zsuzsanna Zborovszky

Study of different parameters (minimum discharge voltage, minimum discharge current, wire electrode diameter, speed of separation, electrode materials, overlap of the electrodes, etc.), their direct effect on the power going into the discharge, and their indirect effect on the possibility of obtaining ignition with an 8.31% methane-air mixture from a resistive circuit. Critical evaluation of the Cadmium disc breakflash (the presently internationally recommended test apparatus). Description of experimental setup and apparatus.

Jan 1, 1974

By P. M. Johnson

A design for a laser-powered optical interferometer, using a specimen whose thermal expansion is to be measured as part of the optical system, was conceived and applied in a prototype dilatometer. The object of thin work was the development of an absolute dilatometer capable of use at elevated temperature, particularly above 1,000° C. The prototype has been operated at temperatures exceeding 1,510° C. Results obtained with this device agree within 2.5 percent with the published data for the coefficient of expansion of columbium.

Jan 1, 1968

By Julius Roth

Flyrock is the source of most of the injuries and property damage in a majority of blasting accidents in surface mines. A quantitative correlation between shot conditions and maximum flyrock range can be used to define a "blasting area" in which no personnel or equipment should be present during a shot. The approach used was to develop a model that correlates shot conditions and initial flyrock velocities and permits computation of flyrock range from ballistic trajectories. The Gurney formula for velocity of explosively-propelled plates or fragments was adapted to explosively-propelled flyrock from vertical rock faces or from bench tops. The modified Gurney formula was then "calibrated" with measured flyrock velocities from mining and explosives literature. Charts were then developed for possible field use which give maximum flyrock range as function of shot conditions. The model indicates that for flyrock from vertical faces, borehole diameter, minimum burden and height of explosive column define maximum flyrock range for a given explosive, shot in a given rock. For flyrock originating from bench tops, flyrock range appears to be controlled by the distance of the top of the explosive column to the borehole collar, by total explosive load per borehole and, to a lesser extent, by borehole diameter.

Jan 1, 1979

By Richard E. Thill

Elastic wave velocities and moduli were determined by both the pulse and resonance methods in a large number of specimens of St. Cloud Gray Granodiorite and Tennessee marble under the same moisture, temperature, and stress environment. Long cylinders were first tested by the resonance method to obtain longitudinal bar and torsional wave velocity. The cylinders were then sectioned in half and tested by the pulse method to obtain the transient pulse velocity. These velocities were later used to obtain various moduli for comparison. Statistical comparisons between the Young's, shear, and bulk moduli and Poisson's ratios obtained independently by the pulse and resonance methods indicate that the methods do not give equivalent results in nearly isotropic rock. The amount of difference varies for each modulus, with the least difference (less than 5 pct) occurring in the shear modulus and the greatest difference (as high as 34 pct) in the bulk modulus. Moduli determinations in aluminum show much closer agreement between the pulse and resonance methods than in rock. The discrepancy in pulse and resonance results probably is caused by frequency dispersion effects and by differences in error sensitivity in the various formulas used to calculate the moduli.

Jan 1, 1974

By Ronald Branstetter

Gaseous and particulate exhaust emissions from 20 diesel engines in service at five underground mines were measured with high accuracy instrumentation. The engines that were tested were checked for faults or maladjustments. The vehicle and engine maintenance organization was studied at each mine and an idealized maintenance program was devised. Faults were induced in a new diesel engine to determine their effect on the characteristics of the exhaust emissions. The results, conclusions and recommendations from this investigation are presented in this final report.

Jan 1, 1983