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By William C. Laubengayer, Robert R. Godard, Harry Dobroski

A whole mine, computer-controlled communication and monitoring system for both normal and emergency use is installed and operating in the U.S. Steel Robena Mine complex near Uniontown, Pa. Portions of the system, including the coaxial cable and the key underground and surf ace phones, have been operating for over a year and a half. During this time the basic concept has been modified and new line amplifiers with directional switches have been developed to eliminate some problems in implementing the loopback feature. The quality of the audio and the availability of the system have been outstanding. Since early summer almost all subsystems have been completed. The experience with the telephone system itself, the pocket-pager call alert, section wireless radio, hoistphone, television, environmental monitoring, control and monitoring of equipment, voicedownlink/code uplink post disaster communications, post disaster through-the-earth monitoring, and the system center failure diagnostic routines are reviewed.

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 John L. Hill

"The Bureau of Mines is conducting research on the causes and methods for control of cutter roof failure in underground coal mines. This hazardous ground control problem exposes miners to the danger of falling roof rock and frequently results in massive roof failure. This report outlines the probable causes of cutter roof failure, which are proposed based on field investigations, numerical model analysis, and in-mine observations. Traditional methods of control are presented, as well as innovative methods based on mining concepts developed during earlier years of coal mining history. The report can be useful to a mine operator for assessing the causes of cutter roof failure on a site-by-site basis and for predicting the probability of its occurrence. A process is presented for selecting an optimum control method that includes both traditional and innovative control techniques for each of the various causes of cutter roof failure. INTRODUCTIONGround control research conducted by the Bureau of Mines is designed to develop technology that will aid in reducing the frequency of accidents associated with poor ground control conditions. Cutter roof failure often poses a safety hazard to miners and causes delays in production while massive roof falls are cleaned up and unstable roof is resupported. Implementation of control measures reduces the threat of injury to miners and prevents production delays.The definition of cutter roof failure used in this report separates this unique type of failure from other ground control problems, to aid in the analysis of the causes and in the development of control methods. The definition is as follows:Cutter roof failure in mine roof rock is a failure process that initially begins as a fracture plane in the roof rock parallel to, and located at, the roof-rib intersection. The fracture propagates upward into the roof over the mine opening at an angle usually steeper than 60° from the horizontal.The mappable extent of cutter failure may range in length from only a few feet to several hundred feet and may traverse entry-crosscut intersections without change in direction. Once initiated along the roof-rib line, a cutter may propagate away from the roof-rib line of one side of a room, cross the roof span, and continue along the other side of the room. It is important to note that this definition excludes a similar type of failure (sometimes referred to as ""kink roof') that has comparable characteristics but occurs in the center of the entry. (The reasons for this distinction are discussed in the ""Background"" section.) Researchers refer to the cutter failure discussed in this report as ""classic"" cutter roof failure; except for short deviations across intersections and entries, initial failure is confined to the roof-rib intersection."

Jan 1, 1986

By Bryan F. Ulrich

If resin-grouted roof bolts are not installed correctly, mine roof reinforcement can be affected, and roof falls can result. A bolt installation variable that is readily controlled by the mine operator is annulus thickness. The objective of this U. S. Bureau of Mines investigation was to study the effect of annulus thickness variations on the integrity of 3/4-in-diam resin-grouted bolts. Forged-head test bolts, 2 and 1 ft long, were installed in concrete blocks that had been drilled with 1-, 1-1/8-, 1-1/4-, 1-3/8-, and 1-1/2-in-diam bits. Standard pull tests were performed; then the concrete was broken away from the bolts so that grout mix quality could be inspected. It was found that the optimum annulus thickness is 1/8-in (l-in-diam drill hole), and as annulus thickness increases from the optimum, there is a corresponding decrease in grout mix quality, effective grout ratio, and axial stiffness.

Jan 1, 1989

Design a model health and safety program which, when implemented, can improve mine safety by reducing occupational injuries and accidents. Approach The Bureau of Mines developed a model program which identifies the elements essential to the effectiveness of health and safety programs designed for mining operations, and is readily adaptable to all types of sizes of mines. The model program primarily provides training on loss control and accident investigation and technical assistance with health and safety problems. In order to assess the effectiveness of the program, it was tested at both a coal and gold mining operation. Monthly statistics were generated to reflect the number of occupational injuries and accidents, and the severity of injuries (as measured by the number of work days lost during recovery). Observations were made of employees performing a large number of randomly selected jobs in order to estimate. the proportion of the workforce that was working in the presence of one or more of three types of safety deficiencies: Type A-individual job performance deficiencies which could be corrected by the employee alone I e.g., an employee is seen not wearing a seatbelt.

Jan 1, 1986

By Robert C. Gabler

The extraction of metals from coal ash was investigated by the Bureau of Mines in an effort to produce a more environmentally acceptable waste and offset waste disposal costs with recovered metal values. The research was conducted in two steps: determination of the parameters that affect extraction of metals from coal ash and development of extraction-recovery procedures. Data obtained indicate that the major parameter affecting the extraction of metals from coal ash is the calcium content of the ash. Other parameters such as furnace type and operating temperature had much smaller effects on metal extraction. Two procedures were studied for metal extraction: an acid leach procedure for high-calcium ashes and a lime sinter-acid leach procedure for low-calcium ashes. An alumina product was recovered that, with sufficient washing, meets Hall cell specifications. The leach residues pass the EPA EP Toxicity Test and are thus nonhazardous wastes available for a variety of uses.

Jan 1, 1983

By I. D. Shah

Thermal decomposition of copper (II) sulfate (CUS04) and copper (II) oxy-sulfate (CuO?CUS04) are important steps in the overall oxidative roasting of covellite (CuS) and chalcocite (Cu2S). Nonisothermal thermogravimetric techniques were used to investigate the decomposition reactions in flowing Na and air. Thermal decomposition of CUS04 and CuO?CUS04 followed "linear" kinetics with an apparent activation energy of 55±2 and 66±3 kcal per mole decomposed, respectively. These apparent activation energies comply with those previously reported when isothermal kinetic techniques were used. The addition of oxygen decreased the rate of decomposition, while small amounts of iron which were admixed with CuO?CUS04 did not have a significant effect. Neither oxygen nor iron had any appreciable effect on the apparent activation energy of the decomposition reaction.

Jan 1, 1972

By L. B. Pankratz

Heat contents were measured for Na2CaSi04 and Na2Ca2S02 between 298° and 1,300° K, for Na2Ca2Si309 between 298° and 1,500° K, and for Na4CaSi3O9 between 298° and 1,350° K. Copper-block drop calorimetry was employed. Reversible, first-order transitions were found for Na2CaSi04 and Na2Ca2Si309. The transition for Na2CaSi04 is at 830° K with a heat absorption of 160 cal/mole; that for Na2CagSi309 occurs at 750° K with a heat absorption of 1,550 cal/mole. Results for the other two silicates showed no irregularities. A table of heat content and entropy increments above 298.15° K and heat con-tent equations are included for use in thermodynamic calculations.

Jan 1, 1968

To determine the effectiveness of multiple types of fire sensors for early and reliable mine fire detection. Background The National Institute for Occupational Safety and Health (NIOSH) has evaluated the effectiveness of multiple types of fire sensors for early mine fire detection and nuisance signal discrimination. Reliable early fire detection in underground mine can be hindered by false fire alarms produced by carbon monoxide (CO) and smoke particulate emissions from diesel equipment, welding, and metal-burning activities. Another false fire alarm source is the cross-interference of hydrogen (H2) produced by battery-charging operations with a CO sensor's chemical cell. Workers can learn to ignore repetitious "false" alarms associated with these emissions. This jeopardizes their safety in the event of a mine fire.

Sep 1, 2002

By James W. Vogh

The report covers initial findings in an experimental program to identify diesel exhaust odorants and determine their contributions to diesel odor. The approach was to isolate selected component groups from exhaust and to evaluate the contribution of each group to exhaust odor. Results were obtained for those carbonyls and phenols that could be isolated from exhaust through inter-mediate conversion to oxime derivatives. Unsaturated aliphatic aldehydes and sterically hindered carbonyls were not included. Hydrocarbons intermediate in the diesel range were "also evaluated and an odor contribution was found from those of the aromatic group. The evaluated carbonyls, phenols, and hydrocarbons were found to account for about 20 pct of the total odor in exhaust from an indirect-injection engine during idle. For exhaust from the indirect-injection engine operating under load and from a direct-injection engine at no load, these compounds were found to have no significant levels of odor.

Jan 1, 1972

By Edward Cogan

Equilibrium phase diagram studies of zirconium- rare earth metal alloys by the Bureau of Mines at its Albany Metallurgy Research Center prompted the development of a rapid gravimetric method for determining rare earths in zirconium in which the rare earths are absorbed from sulfuric acid solution of the alloy on a cation exchange resin . The sample in 10 percent H2SO4 is introduced into the column , the zirconium is eluted with 10 percent H2SO4 , and the rare earths are eluted with (NH4 )2SO4 solution and precipitated with NH4OH . A tracer technique was employed to determine the efficiency of the procedure . Y203 and europium 154 - 152 (Oak Ridge ) were added to 10 g of zirconium and taken through the entire procedure . Recovery averaged 97.6 percent on 0.002 μg europium in the rare earth fraction . Rare earths were determined in the range 0.10 to 90 percent .

Jan 1, 1964

Determine the extent of upper extremity cumulative trauma disorders (UECTD's) in the U.S. mining industry. Background UECTD's are injuries that develop gradually over a period of time as a result of repeated stress to a particular body part without adequate time between stresses for full recovery to occur. The stresses that contribute to UECTD's may occur because of the following work components: awkward position of wrist or arm, excessive manual force, high repetitions of manual movement and effort, cold environment, and vibration. Cumulative trauma injuries to the arm and hand have become an ever growing concern among safety and health professionals in a number of different industries and work settings, such as meatpacking operations, assembly-line work, and keyboarding. Mine workers arc also exposed to a combination of stressors and work design deficiencies that result in arm and hand injuries. For example, certain job tasks and environments, such as that of an underground jackleg driller, expose miners to segmental (hand-arm) vibration and cold temperatures. Operators of underground mobile equipment, such as scoops and trams, regularly have their hands in direct contact with vibrating levers and controls.

Jan 1, 1992

By W. H. Engelmann

The electrokinetic (zeta) potentials of a charcoal granite in an aluminum chloride (AlCl3) solution and in an oleylanunonium acetate (C18H35NH3+ -OCOCH3) solution have been correlated with the specific damping values as measured by the pendulum sclerometer. This investigation shows that the pendulum specific damping attains a minimum at the isoelectric point for the charcoal granite-aluminum chloride and charcoal granite-oleylammonium acetate systems, and thus indicates that the penetration of the diamond points is a maximum at the isoelectric point.

Jan 1, 1967

By W. K. Overbey

Knowledge of fracture systems in oil or gas reservoirs is essential to the efficiency of both primary and secondary production operations. A relationship was established between structural features of the surface and both natural and induced fractures in oil and gas reservoirs, thus providing a method of predicting the direction of rock fracture prior to field development and well completion. Correlations between the surface features and under-ground fractures resulted from analysis of joint strike measurements, bottom-hole impression packer surveys, photographs of hydraulically fractured wells, fracture data from oriented cores, in situ strain measurements from formation outcrops, and lineament analyses from aerial photographs. The mean orientation of surface fractures, lineaments, and stress field directions ranged from N 53° E to N 73° E, compared with an average orientation of N 63° E for the hydraulically induced fractures. Tectonic stress field was shown to influence the direction of hydraulically induced fractures. This report presents the details and application of techniques to obtain the orientation of the principal horizontal compressive stress field component and thus the direction of induced fractures.

Jan 1, 1971

By J. C. Edwards

The Bureau of Mines developed a mathematical model that decribes the interaction of an automated breathing and metabolic simulator, or lung, with a self-contained· self-rescuer that is supplied compressed oxygen. The model can be used to predict the gas partial volumes of 0z, Nz, and COz in the lung and in the self-rescuer breathing bag for a prescribed metabolic state that characterizes the lung. Nonlinear rate equations are used to describe the temporal evolution of the gas partial volumes. A numerical procedure was established with a FORTRAN computer program to solve these equations, which correspond to a given metabolic state. Examples are presented of applications of the model to predict bag volume and bag oxygen concentration changes with time when the bag is controlled by an automated breathing simulator. Under certain restrictive conditions, the model equations can also be used to analytically pre-dict the time required for the bag to reach a maximum or minimum volume. The model equation in this latter case was extended to transi-tions between metabolic states, with transitions described as exponential growth or decay processes.

Jan 1, 1985

By C. W. Owings

Two problems perplex many coal-mine operators and employees. Is coal-mine dust harmful to breathe; and, if so, is it possible to keep the concentration below the danger point? The medical profession is not unanimous in its opinion of the danger of breathing bituminous-coal dust, but there appears to be ample and increasing evidence that coal-mine dust can be harmful if breathed in large enough doses for long periods. The question of controlling the dust at the point of formation is still unanswered in the minds of many in the mining industry. However, results of limited studies conducted by the Bureau of Mines in 9 bituminous-coal mines indicate that a full-shift average exposure of workers should not exceed about 20 million dust particles per cubic foot of air (m.p.p.c.f.) and that concentrations can be held within this limit without too much difficulty. Furthermore, these studies indicated that an exposure in the neighborhood of 40 m.p.p.c.f. should not be exceeded for an individual operation and that it is possible to hold within this ceiling.

Jan 1, 1957

By W. N. Marchant

The Bureau of Mines improved removal of selenium from zinc smelter acidic gas scrubber effluent by using zinc dust to precipitate soluble selenium prior to lime neutralization. Lime neutralization alone decreased selenium in the waste water from, typically, 6 parts per million to 2 parts per million, whereas the use of zinc dust precipitant gave an effluent containing less than 0.1 part per million of selenium. The waste treatment operation first was developed on a laboratory scale and later was successfully tested at a smelter site on a 1-gallon-per-minute basis. During the research a simple and rapid means was developed for determining selenium in waste water; the technique enabled visual semiquantitative selenium determinations that later were confirmed quantitatively by X-ray fluorescence.

Jan 1, 1978

By John D. Sullivan, Edward P. Barrett

The experimental work on the utilization of tin-plate scrap at the North- west experiment station of the U. S. Pireau of Mines in cooperation with College of Mines, University of Washington, necessitated the selection of a simple method for the determination of tin in the iron produced. Some of the standard methods for the determination of tin which were tried are given below: 1. Dissolving in acids and precipitating the tin as sulphide, igniting and weighing as Sn02. 2. Dissolving in aciis, reducing with nickel, cooling in an atmosphere of carbon dioxide, end titrating with standari iodine solution. 3. Dissolving in acids, precipitating the tin as sulphide, dissolving this sulphide in H3 and H2S04, heating until fumes of 503 are evolved, reducing with nickel or sheet lead, cooling in an atmosphere of carbon dioxide, ani titrating with a standard iodine solution.

Mar 1, 1923

By M. D. Schlesinger

Experimental data for coal hydrogenation are presented to show that when a vehicle oil produced from coal is present, coal is hydrogenated to the same high conversion whether molybdenum catalyst is impregnated on the coal or intimately mixed with the slurry. Differences in product distribution could be related to the severity of operating conditions. No minimum mixing time was established, but 2 hours was sufficient. Longer periods of mixing, to 14.75 hours, had no effect on the results. The hydrogenation conditions were in the pressure range of 8,500 to 10,000 p,s,i. at 400° to 500° C. Most of the experiments were made in duplicate. The results were obtained with molybdenum concentrations of 0.01, 0.1, and 1 percent. Al the mentioned pressure range and a time at temperature of 15 to 60 minutes, coal conversions higher than 98 percent were obtained.

Jan 1, 1962

By C. A. Komar

Hardness, tensile strength, and impact toughness of dry and brine-saturated sandstone specimens were measured at ambient, cryogenic, and elevated temperatures as a measure of the relative stability of reservoir rocks for subsurface disposal of liquid wastes. Hardness measurements were inconclusive. Tensile strength and impact toughness were significantly higher at -320° F than at ambient temperature, but were relatively unaffected at 700° F. Impact toughness was reduced by subjecting the specimens to three cycles of rapid temperature changes (thermal shock) over a 1,000° F range. Tensile strength of brine-saturated sandstone was less than that of dry sandstone. Based on results of the tests, reservoir sandstone likely would be stable if exposed to extreme temperatures of liquid wastes, although rapid changes in waste temperatures should be avoided.

Jan 1, 1971