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By G. M. Kintz

The data in this circular were taken from publications of the United States Bureau of Mines and published annual reports of the Wyoming State Inspector of Coal Mines. The tables included are complete only' with regard to major disasters; the Bureau of Mines considers a major disaster one in which 5 or more men are killed. However, minor disasters and gas ignitions recorded in these publications are included. It is known that a number of gas ignitions have occurred of which no record is available. This is one of a series of papers by the Bureau of Mines giving by States available data regarding coal-mine explosions. This information is published in condensed form in the belief that it may be of vale to mine operators in preventing future coal-mine explosions.

Jan 1, 1934

By Robert J. Evans

Capital and operating costs were estimated using a wet suppression, fabric filter, and a combination system of the two for hypothetical hard rock stone crushing plants located in central Pennsylvania, operating at 300, 600, and 1,000 tons per hour. Fixed capital expenditure for the dust abatement systems ranged from $49,129 to $249,162. Annual operating costs for the dust abatement systems ranged from $8,394 to $46,606 (0.9 to 3.2 cents per ton). If these dust abatement systems are properly sized, installed, and maintained, efficiencies approaching 95 percent can be expected for reduction in weight of dust particles emitted before control.

Jan 1, 1975

By P. R. Moyer

"INTRODUCTION The Federal Explosives Act (55 Stat., 863), as amended, was passed by Congress on December 26, 1941, and became effective immediately; it amended the Act of October 6, 1917 (4o Stat., 385). The purpose of the Act was to regulate the manufacture, storage, use, and possession of explosives in order to prevent sabotage and to assure that explosives and ingredients would not fall into unauthorized hands. Under the provisions of the Act, the Director of the Bureau of Mines was authorized to administer its provisions under the supervisions of the Secretary of the Interior.EXPLOSIVES-CONTROL DIVISIONTo administer the Act, necessary personnel were employed in accordance with the appropriation made from a special presidential fund and later by Congress, and the Explosives Control Division was organized as a part of the Health and Safety Branch of the Bureau of Mines constituting the fourth division of that branch. A central office was established in Washington, D. C., and field offices were designated largely at the offices of the Health and Safety Branch throughout the country, and 50 explosives investigators were employed and assigned to work from these offices under the direction of the district engineers of the eight districts into which the United States is divided by the Health and Safety Branch. The territory assigned to each investigator was based on the approximate amount of explosives stored in that area; however, smaller territories were assigned to investigators stationed near the Pacific coast, which was indicated as critical by the armed forces."

Mar 1, 1947

By William C. Larson

A study was conducted by the Bureau of Mines to provide quarry operators with information regarding (1) the effects of jointing and bedding on rock fragmentation when bench blasting in two small-scale (2.5-ft) limestone benches, and (2) the successful use of inexpensive equipment and field techniques to determine the orientation and spacing of joints and bedding separations within the quarry. Using inexpensive equipment, such as a pocket transit and steel and paper tapes, joint and bedding separations were mapped and their frequencies measured. Results from two small-scale bench blasts in the Stewartville member of the Galena limestone formation showed that when the row of vertical blast-holes was oblique to the vertical joint orientations, the backface expression was outlined by two relatively large triangular protrusions (joint surfaces). In this blast, part of the rock burden was unbroken. When the line of vertical blastholes paralleled a predominant joint set, all of the rock burden was broken and displaced. The thickness of fragments that had been displaced by a blast correlated with the observed bedding thickness in the bench.

Jan 1, 1974

By R. O. Dannenberg

The Bureau of Mines investigations described in this report were undertaken to devise a process to economically recover precious metals and copper from low-grade, complex electronic scrap generated in large quantities by military and civilian electronic operations. Leaching with various media is applicable to certain selected items of electronic scrap but cannot be practically applied to complex mixtures of scrap. A process comprising incineration, caustic leaching to remove aluminum, smelting with a siliceous slag, and electrolysis recovered 99.9-percent-pure copper metal and anode slimes assaying more than 7,000 ounces per ton of combined precious metals. Silver, gold, and copper recoveries were 93, 95, and 87 percent, respectively. Cost analysis indicated that an alternative process using direct smelting of the scrap to make assayable products for sale to a custom smelter would provide better overall financial returns.

Jan 1, 1972

By James A. Whelan

The Bureau of Mines sponsored research studies of variables in rotary drilling, done in the Department of Mineral Engineering, University of Minnesota. By studying carefully controlled drilling with good instrumentation, it was hoped to obtain a better understanding of rock failure during drilling and of the stresses in drill bits during drilling. Experimental procedures and equipment are described. From these studies it was concluded that 1. Thrust requirements, other things being equal, are proportional to the total length of cutting edge in the bit. 2. Data from penetrating a wedge into rock under thrust only are not directly applicable to rotary drilling. 3, In rotary drilling the initial wear on a bit greatly decreases penetration rate under any given set of conditions; however, after initial wear the effect of wear on penetration rate is reduced. 4. An increase in rotary speed increases the overall penetration rate but decreases the penetration per revolution. 5. An increase in thrust increases the overall penetration rate and the penetration per revolution. 6, Torque on a drill bit is proportional to both penetration rate and bit diameter. 7. For small-diameter holes full-hole drilling will save both drilling time and energy compared with pilot drilling followed by reaming; for large-diameter holes pilot drilling-reaming is advantageous in both respects,

Jan 1, 1962

By T. T. Read, F. C. Houghten

"The bad effects upon the health and output of miners that result when the ventilating current in a mine lacks sufficient cooling power have been described by Harrington and Sayers in a previous report (1)*** The normal temperature of the human body is about 98.5°F. and whenever work is done by the muscles, indeed even when sitting still, the normal bodily processes generate heat which must be given off, otherwise the body will become overheated and a number of bad effects will be produced. If it were possible to so enclose a man that he could continue to breathe and no heat could escape from his body he would die within a short time. In a series of experiments made at the Pittsburgh Station of the Bureau of McConnell and Houghton (2) found that a dry-bulb and a wet-bulb temperature of 112.5°F could he borne for only 35 minutes, even when the subject was at rest. A wet-bulb temperature of 100.4°F (dry-bulb 157°F) could only be tolerated for 45°F minute. Under such conditions the bodily temperature rises as much as 45°F above normal and the pulse is accelerated. Very uncomfortable sensations are felt when the pulse rate exceeds 135. The human body, like any other internal combustion engine, must be cooled in order to function properly.Under ordinary circumstances the air surroundings people is enough coder than themselves to permit this heat generated within the boiy to be river off with¬out difficulty. At higher temperatures, or when the rate of work, with its corresponding generation of heat is high, the body can not throw off heat fast enough, so it begins to sweat and the evaporation of the sweat cools the body. But the results of the experiments cited above indicate that in still air, even with the body at rent, it can not adjust its temperature when the air is above 90° wet- bulb. J. S. Haldane (4) says ""at a wet-bulb temperature of 60°F the actual amount of work done by the miner begins to fall off; as the wet bulb temperature rinse farther the work Bona gradually diminishes to the vanishing point. Then the temperatures indicated by the wet-bulb exceeds 85°F hard work in a mine seems hardly or the commercial working of a mine the wet-bulb thermometer should not in generaI, be allowed to rise above 80°F, unless perhaps where there it a good current."

Dec 1, 1923

By Lloyd A. Morley

Two methods are presented to determine the mechanical shaft torque as a function of time for an induction motor. The methods are based on the motor equivalent circuit and use as input variables of the motor terminal voltage, line current, input power, and power factor. One method uses all four variables and the other uses only voltage and current. The test data deals specifically with continuous miners, but the theory could be applied to other mining machines driven by multiple induction motors. Results are given for the tramming, maneuvering, cutting, and cutting with loading operations and are in the form of a minimum, a maximum, and an average of the shaft-torque time function. The theoretical development and computer implementation are discussed for both methods.

Jan 1, 1978

By Steven J. Page, John A. Organiscak

Prolonged exposure to airborne respirable coal mine dust is responsible for coal workers' pneumoconi¬osis (CWP): Furthermore, miners who show evidence of higher radiographic categories of simple CWP are at increased risk of developing progressive massive fibro¬sis (PMF). As of 1990, there were nearly 130,000 coal miners in the United States. "' This excludes mines that produce less than 10,000 tons annually and the anthracite coal mines. Estimates indicate that at age 58, an average of 7/1000 U.S. workers and 89/1000 U.K workers will have developed PMF(2-1) Health research studies have iden¬tified that the risk of developing and the severity of CWP arc directly related to (1) the amount of respirable dust exposure and (2) the coal rank.,'- The rank of coal is its stage of formation in the series peat, lignite, sub-bituminous, bituminous, and anthra¬cite (in order of increasing rank). The rank of coal can also be represented by the com¬mercially important characteristics specified by its proximate analysis: fixed carbon, vol¬atile matter, mineral matter, and moisture content.

By S. Benedict Levin

In the spring of 1944, during the emergency In the supply of strategic mica, the Bureau core-drilled six aggregating 913 feet, at the Blister mica Trim. Cheshire County, N.H. These holes indicated a downward extension or the mica shoot which was being mined at that time and developed information essential for economic mining of the deposit.

Jan 1, 1949

By Ann G. Kim, Thomas R. Justin, John F. Miller

The U.S. Bureau of Mines applied its mine fire diagnostic method to an abandoned anthracite mine fire site in Carbondale, Lackawanna County, PA. The technique to locate fires in abandoned coal mines and coal refuse piles includes the determination of hydrocarbon concentrations in mine gases, the imposition of an underground gas flow direction, and use of a surface mapping method, to define heated and cold zones in underground coal strata. The heated zones at Carbondale were characterized by elevated methane concentrations. The results of 25 communication tests were analyzed to define 2 large (approximately 100 by 250 ft) and 5 small, isolated heated zones. An approximate correlation existed between the location of the heated zones and areas of anomalous snow melt. The correlation between the results of the diagnostic test and subsurface temperatures was not significant.

Jan 1, 1992

By Vernon F. Swanson

Several laboratory flotation tests were conducted by the Bureau of Mines on a sample of unweathered diorite from the B. F. Camden property, Amherst County, Va. Results showed that an ilmenite concentrate analyzing 45.5 percent Ti02 (titania), 0.07 percent P205 (phosphorus pentoxide), and 2.21 percent Si02 (silicon dioxide) could be produced from a feed containing 7.72 percent Ti02 and 3.94 percent P205. Ti02 recovery in the concentrate was 47.6 percent in a batch test. The weathered saprolite material overlying the diorite required scrubbing and desliming to remove argillaceous material and preliminary flotation of apatite followed by flotation of ilmenite. The resulting concentrate analyzed 47.3 percent Ti02, 0.19 percent P205, and 0.99 percent Si02 from a starting feed of 8.99 percent Ti02 and 3.37 percent P205; TiO2 recovery was 54.5 percent.

Jan 1, 1963

By J. B. Janus

This report, the 22d in a series, gives analytical data showing composition and quality of tipple and delivered samples of coal collected during fiscal year 1972. This coverage lists mines located in 20 States. Ultimate analyses are given for most of the coalbeds listed. Tipple samples were collected by Bureau of Mines engineers at tipples as coal was being loaded into railroad cars or trucks. The deliveries were sampled in accordance with instructions issued by the Bureau of Mines, and the samples were analyzed in the Bureau laboratory at Pittsburgh.

Jan 1, 1973

By J. H. Adkins

The purpose of this research is to identify hazards associated with roof bolting and to make recommendations for procedural and equipment design changes to reduce those hazards. To that end, the project reviewed Literature on related research, collected and analyzed roof bolting injury data, normalized the injury data be exposure time to each activity and identified problem areas within the root bolting tasks. In addition, field data collection forms were prepared and mines selected for field work. In the field, observations were made of eighty (80) different roof bolting crews bolting one hundred fifty-five (155) place;, on forty (40) sections spread among nine (9) mines. Task analysis forms were used to record unsafe behavior or conditions for each crew and each place. Informal discussions were held with the mine's safety and training officer, the maintenance officer, one section foremen and, when possible, the observed crew, concerning the training and experience of the miners. Unsafe acts were categorized and related to the "Activity While Injured" categories developed during the accident analysis. For each of these categories one or more recommendations for corrective measure, machine modification, procedural change or job training were developed. The study produced over fifty (50) specific recommendations involving machine design, procedural, safety training and supervisional issues that would lead to reduced roof bolter injuries in the near term. The authors concluded, however, that only the development of truly hands off/remote bolting can eliminate or reduce to an absolute minimum the hazards to which the roof bolter is subjected.

Jan 1, 1977

By G. R. Fitterer, C. H. Herty

"INTRODUCTION Manufacturers and consumers of steel have come to realize during the past few years that cleanliness is of great importance in steels which must meet rigid specifications for various physical properties. Of equal importance is the consistent production of steel which is uniform in these properties. For maximum utility steels should be uniform not only from heat to heat, but also from ingot to ingot and within each ingot. In the manufacture of killed steels such as the higher carbon forging grades, uniformity as indicated by the usual chemical analysis in easy to obtain, provided that a normal top discard is taken, as is always the case in steels poured with hot—top practice. No such uniformity, however, holds true for the nonmetallic matter, which consists for the most part of the products of deoxidation of the steel.For a large tonnage of steels which go into articles manufactured by deep—drawing processes, killed steel has never been successfully applied because with the present deoxidation practice, low—carbon killed steel is almost invariably extremely dirty. To obtain the desired qualities for deep drawing, the steel is rimmed, — that is to say, deoxidized with manganese and perhaps a small amount of aluminum, — the resultant product being of high purity in the skin of the ingot, but very badly segregated at the center of the ingot, particularly in the upper—central section. This segregation necessitates a very heavy top discard, and one of the major segregates is carbon which renders the steel too hard to draw properly. If clean, low—carbon killed steel could be made successfully, much better ingot yields would be obtained than by the present rimming steel practice. Furthermore, banded structures and outside and inside seams, which are undoubtedly due in a large measure to blowholes in the ingot, are defects which are very difficult to control in rimmed steel. These defects would be minimized by clean killed steel."

Feb 1, 1931

By E. D. Eastman

The basic character of the free energy r data relating to water and the oxides of carbon makes it desirable that the most representative values that can be obtained should be constantly available. The calculations of Lewis and Randall3 retain much of their of original value, but appear to require some modification in the light of more recent work. This paper has been written to incorporate the newer information and to present some estimate of the reliability of the resulting figures. The data upon which the calculations are mainly based are, for these substances, the equilibrium constants of the various reactions involved. The original work relating to these equilibria has, been reviewed and, where possible, weighted to correspond with its probable reliability. The differences in the results of the present from the earlier calculations are partly the consequence of this appraisal and partly of the inclusion of more extensive data, as will be indicated in detail in the succeeding sections.

Jan 1, 1929

By N. S. Dalal, X. Shi

"Electron spin resonance (ESR) measurements on solutions and isolated powders provide direct evidence for the involvement of Cr(V) species in the reduction of Cr(VI) by NAD(P)H. ESR analysis of an isolated Cr(V)NAD( P)H solid yields 6 11 = 1.9831 and 6.i. = 1.9772, indicating that the unpaired electron occupies the d22 orbital of the Cr(V) ion, with square-pyramidal geometry. Addition of hydrogen peroxide (H2 0 2 ) to the N AD(P)HCr( VI) reaction mixtures suppresses the Cr(V) species and generates hydroxyl (""OH) radicals. The ""OH radicals were detected via ESR spin trapping, employing 5,5-dimethyl-1-pyrroline-N-oxide and a-(4-pyridyl-1- oxide)-N-tert-butylnitrone as spin traps. The dependence of Cr(V) and ""OH radical formation on the H20 2 and Cr(VI) concentrations indicates that the Cr(V) species react with H20 2 to generate the ""OH radicals. Similar results were obtained by using various diols (arabinose, cellobiose, FAD, fructose, glyceraldehyde, ribose, and tartaric acid), a-hydroxycarboxylic acids, and glutathione. Investigations with superoxide dismutase showed no significant participation of 02 in the generation of OH radicals. These results thus indicate that the Cr(V) complexes, produced in the reduction of Cr(VI) by cellular reductants, react with H20 2 to generate ""OH radicals, which might be the initiators of the primary events in the Cr(VI) cytotoxicity.In this paper we report an electron spin resonance (ESR)3 spectroscopic detection of Cr(V) species in the reduction of potassium dichromate, henceforth called Cr(VI), by NAD(P)H and other diols. Also reported here is the detection of the hydroxyl (""OH) radical in the reaction between hydrogen peroxide (H2O 2) and a variety of Cr(V) complexes. This work was undertaken because while the reduction of Cr(VI) to lower oxidation states has been suggested as a key step m the mechanism of Cr(VI) toxicity, mutagenicity, and DNA alteration, the details are not yet clear (1-5).Earlier studies on the mechanism of Cr(VI) reduction in cellular systems include those on the reduction of chromate by microsomes (6-8), rat liver DT-diaphorase (9), and aldehyde oxidase (10). All these studies imply that Cr(VI) can be reduced to Cr(Ill) by cellular constituents. Regarding the mechanism of Cr(Vl) carcinogenicity, Jennette postulated that Cr(V) is the ultimate carcinogenic form of chromium compounds (8). This conclusion has led to many further investigations of the formation of Cr(V) in the reduction of Cr(VI) under biologically relevant conditions (11-33). More recently, however, Kawanishi and co-workers (34) have investigated the mechanism of DNA cleavage induced by Cr(VI) in the presence of H20 2 and have argued that it is not Cr(V) itself that is carcinogenic, but it is the reactive oxygenated species (02, 10 2 , ""OH) (produced by the decomposition of the Crv(02) ¾ - ion) that cause the DNA alteration."

Jan 1, 1990

By Robert L. Marovelli

The thermal conductivities of six rocks were measured by the transient line source method over the temperature range of -850 to 1,500° F. Close-fitting ceramic probes were used in 0.065-inch-diameter holes drilled through 5-to 6-inch-thick rock specimens. Taconite, granite, quartzite, and basalt were used in the tests. The method yields absolute data and is applicable to both laboratory and in situ measurements.

Jan 1, 1965

By L. R. Willmott

An ethanolamine purification unit for removing carbon dioxide and hydrogen sulfide from Firscher-Tropsch synthesis gas was installed at the Bureau of Mines synthetic liquid fuels demonstration plant at Louisiana, Mo. The unit was a surplus Radford Girbotol unit from the Missouri Ordnance Works modified for a capacity of 90,000 std. cu. ft per hour of synthesis gas at 450 p.s.i.g., operating pressure. The hydrogen sulfide loading of the feed gas was specified at 500 grains per 100 cu. Ft. The unit was designed by the Girdler Corp. and installed by the Koppers Co. Initial operations were conducted far 11 days in May 1951. Thereafter 7 additional runs were made, varying lo duration from 8 to 54 days. The last run was terminated on May 29, 1953, the total time the Plant wars in operation being 219 days.

Jan 1, 1956

By Phillip Allender, Wolf Karo, Knox Van Dyke, Lixin Wu, Ali Ardekani, Jorge Garcia, Jaime Gutierrez

"We report that two different micropolystyrene round beads linked to either luminol or lucigenin have been developed. The 1-µ.m-diameter beads arc useful reagents that allow one to perform chemiluminescent (light producing) phagoeytic reactions without opsonization. It is known that luminol reacts with peroxidases (e.g., myeloperoxidase) while lucigenin reacts mainly with superoxide anion. Luminol and lucigenin beads produce cellular chemiluminescence (CL) with neutrophils, macrophages, monocytes, and differentiated human promyelocytic leukemic cells (HL60). When myeloperoxidase (MPO) is present luminol beads evoke higher CL from neutrophils, but when little or no MPO is present, lucigenin beads produce higher amounts of light. Lucigenin beads appear to be active inside these cells where unbound lucigenin does not enter freely.INTRODUCTIONA variety of cells, e.g., neutrophils (Ns) and macrophages (Ms), can engulf foreign particles (1). This engulfing or phagocytic activity is used by the body to kill bacteria and to eliminate foreign particles such as respirable dusts, e.g., coal, silica, or cotton. The neutrophil engulfs or phagocytizes bacteria which are coated with plasma antibodies and/or complement proteins (Fig. 1). The coating or opsonization allows the neutrophil to recognize foreign substances. Usually the absence of opsonization prevents the cell's recognition of a foreign particle and the particle is not phagocytized. Macrophages, particularly the alveolar Oung) cells, do not require opsonization for phagocytosis. Ms should not be selective toward individual dusts because they serve a major role in eliminating a variety of these.Particle size can also be a factor. Usually a particle with a diameter of 0.5-5 µ.m is considered in the respirable range. Larger particles are trapped before they reach the alveoli Oung spaces where oxygen exchange with blood occurs), ·and smaller particles do not generally settle, and are not engulfed by macrophages (2). Tabato and Ikada (3) found that maximal phagocytosis of microspheres takes place when their diameter is in the range of 1.0 to 2.0 µ.m. In addition, they found that beads with hydrophobic surfaces were more readily phagocytized than hydrophilic surfaces."

Jan 1, 1990