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By M. J. Ackerman, C. R. Waine, W. M. Merritts, L. P. Mokwa

Tests were conducted in the Pocahontas No. 4 coalbed in southern West Virginia to determine if successful degasification techniques, developed during an earlier study in the Pittsburgh coalbed, would be effective in removing methane from those usually more gaseous coals. Specially designed long-hole drilling equipment and Bureau of Mines continuous recording devices were used to measure the quantity and methane content of the ventilating air during the investigation. Infusions were made with water at normal waterline pressures ranging from 200 to 220 psi or at pump pressures ranging from 400 to 650 psi. Results of the tests showed that methane emissions from free-flow bleeder holes were as much as 131 cfm. Infusions of some of the holes increased the methane emission from other holes and from the exposed coal surfaces near the working areas as much as 1,540 cfm. The methane content in the main return-air currents after infusion was reduced more than 86 percent of the amount recorded before tests were made.

Jan 1, 1963

By Donald P. Blasko

The Bureau of Mines investigated two areas of the Alaska Peninsula (Iniskin Peninsula and Becharof Lake) where oil and gas seeps were known to occur in an attempt to determine (1) whether the seeps are still active and (2) the amount of bitumen contained in the drainage leaving the seeps. The oil, water, oil-water, and gas were sampled and analyzed. Five oil samples were taken at four separate oil seeps. The API gravity of the oil ranged from 8.90 to 21.4° and the sulfur content was from 0.12 percent to 0.59 percent. Four of the seven gas samples obtained revealed fair high caloric values, ranging from 746 to 924 Btu/cu ft, and averaging 844 Btu/cu ft. A total of 44 water samples were obtained. Bitumen content of the water was as high as 9,773 mg/l at one seep, but averaged less than I mg/l where the seep-drainage water entered the Gulf of Alaska.

Jan 1, 1976

By M. M. Fine

This report describes a Bureau of Mines technical feasibility study of simultaneous reduction and induration of pelletized iron ore to make a product with superior qualities as blast-furnace feed. Highly reduced, physically competent pellets can be made from magnetite and specularite concentrates that contain small additions of bentonite as binder. In batch tests, pellets were dried, surrounded with solid fuel in crucibles, and heated to the reducing temperature. Total iron content of the best products was higher than 80 percent and crushing strength of 1/2-inch metallized pellets ranged up to 600 pounds or more. Comparative tests of several commercial oxide pellets showed a wide range in crushing strengths, but most values were less than 350 pounds. Continuous tests in a rotary kiln resulted in the same degree of reduction, but the pellets had lower crushing strengths because of the limitations in the maximum operating temperature of the small kiln.

Jan 1, 1962

Develop a training program to help mine workers effectively fight small fires in underground Goal mines. Training would enable miners to make rapid judgments on whether to attempt extinguishment, and how best to use the firefighting equipment on hand. Approach Fire reports were analyzed to define and delineate physical and behavioral variables which affect firefighting activities, and to determine effective procedures for extinguishing small fires. A course was then designed to train miners in such procedures. Finally, the course was reviewed by industry experts and administered to a group of miners to determine needed revisions and to validate the course. How It Works Analysis of fire data showed that six items should be emphasized in teaching proper fire response: 1. Alertness to fire potential. 2. Immediate power cutoff. 3. Internal, external communication. 4. Teamwork in fighting fires. 5. Role of ventilation and position of men inby the fresh air side. 6. Effective use of fire suppressant materials.

Jan 1, 1983

By Richard J. Mainiero, Harry C. Verakis

The Bureau of Mines has conducted research to determine whether the total elapsed delay time for blasting bituminous coal in underground mines could be safely expanded beyond the present 500-ms limitation without igniting a methane or methane-coal dust atmosphere. The results indicated that the increase of total delay from 500 to 1,000 ms had no detectable effect on safety relative to incendivity as long as permissible practices were observed in all other aspects. Research was also conducted to evaluate the safety of 18-in hole spacing for delay blasting in coal relative to misfires. For a variety of permissible explosives, misfires were observed for about 50 pct of the holes at 18-in spacing. Based on this observation, the Bureau has recommended that the new regulations prohibit hole spacings of less than 24 inches in underground coal mines. Misfires were also observed for 24-in spacing, but the number of misfires and test shots was too small to sup- port any firm conclusions.

By S. P. Howell

The Bureau of lines as repeatedly called attention to dangerous practices in the transportation and opening of kogs of black blasting powder. In 1914 Diwin Higgins (Prevention of Accidents from Explosives in Metal inos, Miners' Circular 19, Bureau of Mines, p. 15) stated "canisters should always be opened by removing the bung. To use a pick or other sharp tool for cutting a hole in the canister is dangerous. After the necessary amount of powder has boon taken out, the canister should be kept closed. The powdor should always be handled at a safe distance from an open light." In 1919, Geo. S. Rice (onthly Statement of Coal line Fatalities for June, 1919, Bureau of Mines, pp. 16 to 18) calls attention to the dangers that arise in underground transportation and handling of explosives, and calls special attmtion to the danger of hauling explosives in motor trips; the unnecessary risk involved in hauling men on the trip at the same time, and the necessity of keeping open lights away from black blasting powder. In 1919 the writer (Sensitiveness of Explosives to Frictional Impact, Tech. Paper 234, Bureau of Mines, pp. 13, 15) called attention to the fact that black blasting powder is not as sensitive to frictional impact as the nitro-glycerin dynamites and the gelatin dynamites. Black powder may be ignited by direct impact and the writer believes that this may occur without presupposing a preliminary spark. It is well known, however, that black blasting powder is very sensitive to ignition by spark flame, or heated materials, and these may be produced by an electric current, by an open light, by incandescent particles from a pipe, cigar, or cigarette, by the tearing of metal sheets or scraping of metal against metal, and possibly, by other means. -- The above discussion will serve to introduce a newly recognized hazard the ignition of black blasting powder by the forcible opening of kegs with wodden tools. The details of three accidents in which kegs of black blasting powder ex- ploded instantly when a wooden tool was driven forcibly through the top of the kegs are as follows: 1. In 1915, a powder man employed by a coal mining company stated that he was opening a 25-pound log of black blasting powder by driving a hole in the top with a wooden sprag when the powder in the leg ho was opening ignitod. This caused the ignition of fifty-two additional 25-pound logs of the powder, and the fatal burning of this and another powder man. The ono making this statement lived five hours after the explosion.

Sep 1, 1920

By E. O. Binyon

The Blue Metal corundum-andalusite deposit, in the Buckskin Mining district, Douglas County, Nev., was explored by the Bureau of Mines in 1945. The results of that work were presented in Report of Investigations 3895, exploration of the Blue Metal Corundum Property, Douglas County, Nev. published in August 1946. That report also describes the property in detail, giving location, ownership, history, geology, and data on beneficiation tests. Further exploration was carried on in April and Way 1947, the results of which are presented in this report. The work consisted of 175 feet of drift and crosscut, bringing the total to 398 feet of underground working, as shown in figures 1 and 2. The 23-foot drift, which was the last work of the initial project, was extended 99 feet northward along the shear zone, and three crosscuts, spaced at approximately equal intervals along the drift, were driven to country rock on the hanging and foot walls of the zone.

Jan 1, 1948

By Robert J. Timko

The objective of this Bureau of Mines research work was (1) to determine how well the E. I. Du Pont de Nemours and Company P-2500 personal dust sampling pump controls the flow rate at 2 L/min and (2) to compare respirable dust mea-surements made using the P-2500 with those made using a nonpulsating sampling flow system, both using the Dorr-Oliver 10-mm nylon cyclone dust size classifier. The calibrator and the operation manual for the P-2500, supplied by the manufacturer, were also evaluated. Flow tests consisted of long-term (6-to 8-hour) flow stability tests at various backpressures, a low-flow indicator examination, flow controller response time tests and pulsation tests. Dust tests were performed using coal, silica, and Arizona road dust. No tests were performed to examine effects of temperature, barometric pressure, vibration, or mechanical shock. These pumps performed well within manufacturer specifications in all tests.

Jan 1, 1982

By Edmond Chin

Mineral production was of minor importance to the country's economy, and Bangladesh was not a ranking world producer of any mineral commodity in 1980. Natural gas was the most important mineral exploited, and reserves were sufficient to allow a significant increase in its use. A greater proportion of the domestic heat and electrical energy needs could be filled by increased production and distribution of natural gas. Also, the export of natural gas was feasible either by pipeline to India or in the form of liquefied natural gas (LNG). Some nonmetallic minerals could be developed, as well as coal and peat, given sufficient capital investment. Bangladesh's strongly agricultural economy made fair progress in 1979.80.1 The major harvest of November-December 1979 turned out to be better than had been anticipated after an early drought left poor planting conditions. Secondary crops (harvested in February-March 1980 and June- July 1980) were excellent. There were prospects for a record harvest in fiscal year

Jan 1, 1982

By M. M. Tilman

The Federal Bureau of Mines developed a rolling method that improves creep resistance and yield strengths of lead alloys containing up to 5 wt-pct Sb. The 0.69-inch-thick slab-cast alloys were breakdown-rolled to 0.226 inch and finish-rolled to 0.063 inch at 5-or 20-pct reduction per pass. Rolling was at room temperature to simulate conventional cold rolling, and at 75°, 125°, and 175° C. Two alternative methods evaluated consisted of (1) a single cold final pass followed by annealing and (2) a single hot final pass. Two additional processing methods involving percipitation strengthening were included for comparison. Compared with conventional cold rolling, hot rolling at 125° and 175° C with multiple light passes vastly improves creep resistance and raises yield strengths. Tensile strengths are less affected. The other treatments also improve creep resistance significantly and generally improve tensile properties; magnitudes vary with treatment and composition.

Jan 1, 1975

By R. L. Montgomery

The heats of solution of erbium chloride in water and in hydrochloric acid and of erbium oxide in hydrochloric acid were determined. The results reveal a discrepancy of 10.5 kcal. per gram-atom between the heats of combustion and solution of erbium reported in the literature, the heat of combustion being more negative. The heat of combustion of erbium t4)4 and its heat of solution in hydrochloric acid (1, 18) have been reported in the literature. The heat of solution of erbium chloride was determined in two studies (2, 19). The present work was undertaken to check the reported heats of solution of erbium chloride and to determine the heat of solution of erbium oxide in hydrochloric acid. The latter quantity permits the heats of combustion and solution of erbium to be compared for mutual consistency. It was also desired to determine the degree of similarity between the thermochemistry of yttrium and erbium.

Jan 1, 1961

By W. A. Cole

The sulfur shortage that existed during the Korean conflict stimulated interest in coal measures as possible sources of sulfur. One of the areas brought to the attention of the Bureau of Mines was in Marion County, Iowa, where comparatively high-sulfur coals and other marcasite-bearing strata were known to occur. A Bureau of Mines engineer inspected the marcasite occurrence on December 4, 1954; this prompted further work on the Iowa coals and associated formations as a source of iron sulfides. An investigation of the Iowa high-sulfur coals was undertaken including core drilling, field reconnaissance, and compilation of data pertinent to consideration of the following: 1. Upgrading Iowa coal by mechanical cleaning and the feasibility of recovering sulfur from coal brasses. 2. Possibility of processing the high-sulfur coals by adaptation of methods employed in processing industrial gases to produce sulfur and sulfur products. 3. Possibility of finding concentrations of iron sulfides in associated rock formations in sufficient quantity for economical recovery.

Jan 1, 1957

By Maria I. De Rosa

The U.S. Bureau of Mines performed experiments to determine if the primary gas toxicities evolved during the early (-300° C) and later (>400° C) combustion stages of mine conveyor belts could be predicted by a smoke particle characteristic. The experiments were conducted in an approximately 20-L furnace at set furnace temperatures of 150°, 250°, and 1,000° C, with a furnace airflow of 10 L/min. The variables studied, as a function of time, included hydrogen chloride and carbon monoxide concentrations, the average smoke particle diameter (d8 and number concentration (no), and the product of the average smoke particle diameter and concentration (dgn0) Other variables included the sample and furnace temperatures and the sample mass weight loss. Results show that the inverse of the smoke particle diameter-concentration product (ldgn0), correlates directly with the hydrogen chloride and carbon monoxide toxicities released in large quantities during the early and later stages of combustion.

Jan 1, 1989

By John A. Organiscak

The Bureau of Mines has recently completed a program to identify and evaluate various methods that address control of dust generated outby the longwall mining face. Dust generated by the stageloader-crusher, the panel belt, and the intake roadway can be long-term throughout the shift, contributing significantly to the dust exposure of all face workers. Dust control techniques were identified and tested at a number of longwall mining sections located in diverse geological conditions across the United States, Dust controls investigated include (1) methods that eliminate the sources of intake dust contamination--homotropal ventilation; (2) methods to limit the amount of respirable dust released into the intake airstream--improved water application and the use of curtains and enclosures; and (3) methods to clean the contaminated air prior to delivery to the mining face--scrubber systems. Usually they can be implemented at a low cost and can be very effective. This report describes each technique and its application and presents the resulting conclusions.

Jan 1, 1986

By P. D. Laverty

The U.S. Bureau of Mines treated mixed and contaminated super alloy scrap by pyrometallurgical and hydrometallurgical methods to separate and recover metal values. Best results were obtained by leaching Zn-treated or atomized scrap with HCI-02 at 9SO C and 50 psig 02' This resulted in dissolving approxi-mately 98 pet of the AI, Co, Cr, Cu, Fe, Mn, Ni, and Zn while rejecting over 98 pct of the Mo, Nb, Ta, Ti, W, and Zr as an insoluble refractory residue. Chlorine was successfully substituted for HCI to leach Zn-treated scrap but was unsuccessful for leaching atomized scrap. The leaching solution was treated by pH adjustment and hydrothermal precipitation at 2000 C for 4 h to remove AI, Cr, Fe, and other contaminants as a filterable precipitate. Recovery of Co and Ni would be accomplished by solvent extraction and e1ectrowinning. Chromium recovery as a ferroalloy was demonstrated.

Jan 1, 1989

Improve the effectiveness of face ventilation systems in coal mines by minimizing leakage around line and check curtains. Approach In-mine surveys were conducted to determine current curtain construction techniques, their effectiveness and associated costs. In addition, performance characteristics of extensible curtains were evaluated. A total of 77 conventional curtains in 10 mines was examined for 12 important characteristics. Extensible curtains were erected in a full-scale model and examined for operational difficulties, effects of leakage, and air pressure. Survey Results The underground mine study identified four categories of face brattice construction ranging from simple to complex: 1. Simple suspension of the curtain from roof bolts with the bottom edge lying on floor. 2. Spadding of the curtain to the roof on about 12-inch centers and stabilization of the bottom edge with wood or rock. 3. Use of vertical props and spads with a base board for support on the bottom. 4. Use of vertical props with caps and bottom boards plus horizontal brattice support boards.

Jan 1, 1984

To produce industrial-grade titanium castings by processes that are nonpolluting and lower cost than the currently used rammed-graphite process. Approach Foundry-grade zircon and olivine sands, bonded by waterglass or bentonite, are used to make shell or rammed molds which require relatively low-drying temperatures and do not generate noxious fumes during drying or casting. Procedures Three separate processes have been developed which meet the stated pollution and cost goals. These are: 1. Waterglass-bonded rammed zircon or olivine sand molds are dried at 480°F, zirconia washed, redried, and used in an inductoslag or skull-casting furnace. 2. Waterglass-bonded zircon or olivine sand shell molds are formed at 560°F, cured at 620°F, zirconia washed, dried at 480°F. and used in an inductoslag furnace. 3. Rammed zircon and olivine sand molds are bonded with western bentonite, zirconia washed, dried at 980°F, and used in an inductoslag or skull-casting furnace.

Jan 1, 1981

By Richard J. Mainiero

The Bureau of Mines investigated coal-mine-type short-delay electric detonators marketed by three domestic manufacturers to determine the accuracy of delays and the probability of overlap between adjacent de- lay periods. The Winzer index was computed and compared with the probability of overlap. A close agreement between the Winzer criterion and overlap probability was demonstrated. A permissible blasting unit capable of delivering a maximum firing energy of 4.0 J and a digital oscilloscope were used to measure the delay time with an accuracy of 20.25 ms. Another oscilloscope and a pulse transformer were used to record firing current. Experimental data indicated negligible overlap probability in detonators of shorter delay periods: periods 1 to 4, which correspond to 25 to 250 ms. However, a significant probability of overlap was detected in some detonators of longer delay periods: periods 5 to 9, which cor- respond to 300 to 500 ms.

Jan 1, 1985

"A coordinated, integrated research effort aimed at studying the scientific, engineering and medical aspects of the respirable dust problem is underway in the areas of dust generation, dust dispersion and dilution, dust characterization, interaction of dust and lungs, and relationship of seam characteristics to dust generation and mobility. (FIGURE 24) The Center's research program explores these concerns with the objective of refining existing strategies and developing new respirable dust control techniques that are consistent with the dust-lung interaction processes that lead to mine worker disability. The fundamental aspects of this work are applicable to the control of respirable dust problems in both hard rock mines and coal mines and to other dusts such as diesel-generated.Research projects in the Generic Mineral Technology Center for Respirable Dust have effected several improved methods for the preparation and characterization of the dusts needed by these projects. Superior procedures for generating ""standard"" dust samples have been developed and are in regular use in the laboratory. Questions raised during the course of some projects regarding ""stale"" versus ""fresh"" dust have led to the development of sampling techniques where the dust is directly collected in a surfactant. MSHA and CANMET have requested and received information on Center generated software. An equipment manufacturer, TSI, Inc., requesting input on modifying the inlet of an aerosol sampler has been assisted as a result of research that was conducted at the University of Minnesota.The objectives, scope and progress of all the research projects in the Center, in the form of abstracts and reports, have been detailed in Volume 1 of this series. Research papers written by the principle investigators and resulting from the findings of projects (FIGURE 25) and which are funded by U.S. Bureau of Mines grant number G1135142 have been published in Volumes 3 through 6 and Volume 8 of this series. Volume 2 relates the cooperation and interaction of the U.S. Bureau of Mines and the Generic Mineral Technology Center for Respirable Dust in research on the problem of respirable dust in the mineral industries."

Aug 31, 1989

By John J. Sammarco

Computer-related accidents have caused injuries and fatalities in numerous applications. Normal Accident Theory (NAT) explains that these accidents are inevitable because of system complexity. Complex systems, such as computer-based systems, are highly interconnected, highly interactive, and tightly coupled. We do not have a scientific methodology to identify and quantify these complexities; specifically, NAT has not been operationalized for computer-based systems. Our research addressed this by operationalizing NAT for the system requirements of safety-related computer systems. It was theorized that there are two types of system complexity: external and internal. External complexity was characterized by three variables: system predictability, observability, and usability -the dependent variables; internal complexity was characterized by modeling system requirements with Software Cost Reduction dependency graphs, then quantifying model attributes using 15 graphtheoretical metrics the independent variables. Dependent variable data were obtained by having 32 subjects run simulations of our research test vehicle: the light control system (LCS). The LCS simulation tests used a cross-over design. Subject perceptions of these simulations were obtained by using a questionnaire. Canonical correlation analysis and structure correlations were used to test hypotheses 1 to 3 - the dependent variables predictability, observability, and usability do not correlate with the NAT complexity metrics. Five of 15 metrics proposed for NAT complexity correlated with the dependent data. These 5 metrics had structure correlations exceeding 0.25, standard errors < 0.10, and a 95% confidence interval. Therefore, the null hypotheses were rejected. A Wilcoxon signed ranks test was used to test hypotheses 4 to 6 - increasing NAT complexity increases system predictability, observability, and usability. The results showed that the dependent variables decreased as complexity increased. Therefore, null hypotheses 4 to 6 were rejected. Lastly, this work is a step forward to operationalize NAT for safety-related computer systems; however, limitations exist. Opportunities addressing these limitations and advancing NAT were identified. Lastly, the major contribution of this work is fundamental to scientific research - to gain knowledge through the discovery of relationship between the variables of interest. Specifically, NAT has been advanced by defining and quantifying complexity measures, and showing their inverse relationship to system predictability, observability, and usability.