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By Fred N. Kissell

Methane flows and pressures were measured in mines in the Pittsburgh, Hartshorne, and Pocahontas No. 3 coalbeds. From the data, the permeability of each of these coal beds was computed. It was found to depend strongly on the type of coal and on the amount of water in the coalbed, and it was found to increase with time. All of the coalbeds had a high-permeability zone adjacent to the face or rib, and the Pittsburgh bed exhibited directional anisotropy. Surprisingly, little or no overburden effect was observed.

Jan 1, 1972

By M. V. Potter

"In nearly all fields of investigation, research laboratories and routine testing laboratories encounter problems in which the primary determinations involved in the study require the measurement of mechanical vibrations or motions. These vibrations,may be of an oscillatory nature covering frequencies from a few cycles per second up to hundreds of Kilocycles per second, or they may be more or less uniform study nations occurring at rather slow rates. In electrical, or mechanical methods. In the optical case the to cause the deflection of a light beam such that the motion of the mechanican system of the beam can be determined, then by direct the by direct observation on a suitable scale or by recording it’s the electrical methods the motions can be made to changes in resistance, capacity or inductance proportion to the mechanical displacement or electromagnetic means can used to generate directly a voltage that will be porpertuial to the instantaneous vicinity of the vibrations. Other devices are used in a special instance, also but in any cause the electrical methods produce a current that is an electrical counterpart of the mechanical motion, and the motion can then be studied by direct measurements of the current or by recording the current on suitable recording meters or oscillography. Mechanical methods are used in some instance but are generally not as convenient nor as flexible as the optical and electrical methods."

Feb 1, 1943

By David Hoadley, Kenneth R. Maser, Ashok B. Boghani, James E. Billar, D. Randolph Berry, Mackenzie Burnett, Robert H. Trent

5. General Escapeway Requirements 5.1 Escape Routes Present escapeway regulations state "Every mine shall have two separate properly maintained escapeways to the surface which are so positioned that damage to one shall not lessen the effectiveness of the other, or a method of refuge shall be provided when only one opening to the surface is possible." "Escape routes shall be a. Inspected at regular intervals and maintained in safe, travellable condition, b. Marked with conspicuous and easily read direction signs that clearly indicate the ways of escape." "Application. "Regular" intervals means at intervals no greater than monthly where conditions are stable and oftener where conditions may change." "Designated escapeways inclined more than 30* from the horizontal shall be equipped with stairways, ladders, cleated walkways, or emergency hoisting facilities." As can be noted in present and proposed regulations there must be two separate properly maintained escapeways. In most operations, the escapeways will consist of one route that is the normal travelway used in day to day operations. The second route is usually a return airway through old work areas. Based on this generally accepted practice, we will designate the two types as primary and secondary.

Jan 1, 1976

By D. E. Shanks

The Bureau of Mines investigated the effects of HCI concentration and solution temperature on the solubility and crystal form of the chlorides of Co, Mn, and Ni when sparged with HCI gas at temperatures of 20°, 40°, and 60° C. Increasing HCI concentration in solution caused the chlo-rides of Co, Mn, and Ni to crystallize (salt out) because of the common ion effect. The salting-out crystallization was most effective for NiCI2, which had a solubility of 0.7 pct at 20° C and maximum HCI concentration. COCl2 salted out to a minimum solubility of 9.4 pct at 20° C and 22 pct HCI concentration and increased in solubility at greater HCI concentrations because of the formation of chloride complexes. MnCl2 was intermediate in behavior. The effect of temperature on solubility was greatest for CoCl2 and least for NiCI2, 15 and 7 pct change, respectively, over the temperature range of 20° to 60° C. The salted-out chlorides of cobalt and nickel formed the hexahydrates and those of manganese formed the tetrahydrate in saturated metal chlo-ride solutions at 20° C and low concentrations of HCI. Increasing the temperature or the HCI concentration caused a 108s in waters of hydra-tion. At 60° C, the salted-out crystals of NiCl2 formed the tetrahydrate in HCI concentrations up to 18 pct and the dihydrate at higher concentrations, while cobalt and manganese chlorides formed the dihydrates, even in water.

Jan 1, 1985

By S. J. Pearce

The need for a simple, very sensitive, and accurate method for the determination of benzene in blood and urine vas evident throughout a recent study of chronic benzene (C6H6) poisoning conducted cooperatively by the United States Bureau of Mines, The Barrett Company, and the producers of benzene. A combustion method which will be described in a later publication, and a previously described/ adaptation of Smyth's method were developed and used during that investigation. The adaptation of Smyth's method gave satisfactory results when dealing with exposure conditions that produced chronic poisoning in a comparatively few days, but it was time-consuming; and lacked the accuracy necessary for a study of the absorption, distribution, and fate of benzene in the body during exposure to threshold concentrations of benzene vapor in air. The combustion procedure was satisfactory from the standpoint of sensitivity but was cumbersome, intricate, time-consuming, and required the use of special and somewhat expensive Physical and chemical apparatus. Following the termination of this study of chronic poisoning, possibilities ides for developing better methods occurred, and these have been investigated by the Bureau of Mines with the aid of Relief Works Division personnel microcolorimetric method for the determination of benzene in air has been described recently.6/ The present report deals rich the adaptation of this new colorimetric method to the determination

Jan 1, 1936

By J. C. Nigro

Hematite-to-magnetite reduction kinetics were investigated mainly in CO-CO2 atmospheres at temperatures ranging from 500° to 1,000° C. Reduction rates were measured with a thermobalance, which recorded the weight loss as the specimen was reduced. Reduction data on both synthetic and natural hematite spheres showed good linearity of ro [1-(1-R)1/3] with time, t, up to over 85 pct conversion to magnetite; the rate coefficient (k[L], cm/min) obtained from the linear portion of the plot was used to characterize the penetration rate of the hematite-magnetite interface. Gas composition, porosity, and silica content were major factors affecting the rate. Temperature dependency of the reaction rate was small, yielding a mean activation energy of about 3 kcal/mole. Silica additions increased the reaction rate, probably through an increase in the effective surface area and diffusion; however, above 900° C, silica can react to form fayalite. Experimental data showed that the linear thickening rate of the magnetite layer, normally evidence of a chemically controlled reaction, can also be indicative of a reaction controlled by both mass transfer and diffusion. Evidence from this study indicates that the dominant rate-controlling factor in the reduction of hematite to magnetite at high temperatures is transport in the gas phase.

Jan 1, 1973

By C. J. H. Brest van Kempen

The objective of this contract was to provide thrust and torque control and visual output torque readout systems to an existing mine roof bolting machine and to test the consistency of torques obtained under actual field conditions. A Lee Norse TD1 roof bolter was modified by adding a simple torque sensing device to the drill rotation mechanism and a pneumatic logic control circuit that measures torque and controls the hydraulic circuit to the rotation motor. The modification controls and indicates the final installation torque of mine roof bolts. A total of over 5,000 mechanical roof bolts were installed in an operating coal mine. The installed torque of these bolts were within an error band (standard deviation) of 8%.

Jan 1, 1978

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Jan 1, 2011

By Robert H. Bedford

The Rogan-Mallery tin property is in the foothills on the south slope of the Tehachapi Mountains, Kern County, Calif. It was first visited by the senior author in August 1942, and exploration by means of trenching and diamond drilling began in May 1944 and was concluded in August of the same year. Cassiterite, associated with iron-rich gossan, occurs in a limestone roof pendant at places near or at its contact with the underlying granitic rocks. The cassiterite grain sizes range from 20 mesh to 150 mesh. Surface and diamond-drill samples showed tin ranging from traces up to 122.6 pounds per ton. Exploration by the Bureau of Mines included 2,100 cubic yards of trenching and the drilling of 11 diamond drill holes totaling 1,000 feet. Dana Hogan, president of the Rogan Petroleum Co. of Los Angeles, Calif.) brought these projects to the attention of the Bureau of Mines in July 1942, and the following month a Bureau engineer made a preliminary examination in company with Hillard Mallery, of 408 Ruby Street, Redondo Beach, Calif., the man who discovered them.

Jan 1, 1949

By Joseph Cervik

Gas occurs in coalbeds in an adsorbed and a free gas state. Adsorbed gas is stored in the micropore structure and its transport is governed by Fick's law. The free gas occurs in the fracture system and flows according to Darcy's law. These two modes of mass transport are interdependent. Production decline curves of coal-gas wells are of the constant percentage decline type and, thus, show no indications of flow characteristics peculiar to coal-gas reservoirs. The effectiveness of surface boreholes as a degasification scheme depends upon both good fracture permeability and a high fracture density. Conventional methods of reservoir engineering analysis are not applicable to coalbeds

May 1, 1969

By G. E. Bobeck

The first year's work of a proposed three-year study of the effects of the exposure of coal mine roof rocks to the mine atmosphere has been completed. The project has been terminated. The goal of the project was to determine if possible the mechanism or mechanisms by which coal mine roof rocks interact with the mine atmosphere and weaken, and coupled with mechanical stresses, ultimately fail. The scope of the study was limited to the effects of environmental factors on the deterioration of the rocks. While mechanical stresses may play an important role in the interaction of environmental factors, stress effects were excluded from the study. In order to study the effects of environment on coal mine roof rocks, samples were obtained from several coal mines in the western states. The rocks forming the roofs of most of the mines visited were shales of varying composition. These shales were subjected to numerous tests to determine how the rocks changed with time after exposure. In addition, the identity of the minerals present in the shales was determined by x-ray diffraction analysis and by thermal analysis as well as by optical microscopy

Jan 1, 1973

By Janet Torma-Krajewski, Pauline Lewis, Paul Gust, Lisa Steiner, Kean Johnson

Since 1990 and the publication of the Ergonomics Program Management Guidelines for Meatpacking Plants by the US Occupational Safety and Health Administration, numerous reports of companies implementing ergonomics program have been published. However, despite these numerous reports, no examples of implementing an ergonomics program in the mining industry have been reported. In 2000, NIOSH initiated a long-term project to demonstrate the implementation of an ergonomics process designed to identify and reduce exposures to ergonomic risk factors found in mining. The mine selected for this project was the Jim Bridger Mine, a surface coal mine located 35 miles northeast of Rock Springs, Sweetwater County, WY. This paper discusses how a large, surface coal mine implemented an ergonomics program and the lessons learned while doing so.

By John B. Goodman

This report presents a study of a modification of the precision laboratory carbonization-assay apparatus that renders the unit capable of performance at low-, medium-, and high-temperature assay levels and permits, under controlled conditions, evaluation of the relationship between carbonization temperature and the yield of pyrolysis products. Second, the interest and value derived from the temperature study data directly apply to the particular semiplant carbonization processes and techniques currently being investigated in this laboratory. Data obtained with the assay apparatus enables the fuel technologist to predict the probable yields of carbonization products from pilot-plant operations under various carbonizing conditions. Data obtained with the assay apparatus has been used to predict the product yields of industrial carbonization plants at Kemmerer, Wyo., and Rockdale, Tex. The assay provides a useful tool in detecting, from the carbonized plant product, the degree of effectiveness of pilot-plant operation. Third, the residual volatile matter in some industrial carbons has broad significance. Evaluation of the volatile material remaining with or in the carbon may be assessed through the high-temperature-assay technique. The low-temperature carbonization assay devised by the writers has proved to be a versatile tool in predicting the probable product yields from pilot-scale carbonization processes. The apparatus described in previous publications has been modified to extend the range of testing above 500° C. without impairing the accuracy and reproducibility obtained in the low-temperature range. Results presented here include product yields from a typical Texas lignite and Wyoming subbituminous-B-rank coal over the temperature range 150° to 1,000° C.

Jan 1, 1958

By J. Baicker

A two-inch diameter probe containing an intrinsic germanium detector, a canister-type solid cryogen cooling system, cooled FET preamplifier, linear amplifier, high voltage supply, analog-digital converter, microprocessor, buffer memory, bidirectional cable link, and all power supplies has been designed, assembled and tested. A surface support vehicle was designed, built and outfitted. A mini-computer system was constructed and preliminary software developed and tested. A special handling system for a Cf-252 neutron source was designed and has been ordered. The entire system (less the neutron source) is ready for its first field tests. Lab description of the system is presented.

Jan 1, 1978

By John P. Capp

Addition of sintered fly-ash/bottom-ash mixtures to rubber formulations failed to increase the skid resistance of the resulting products. Wear, tensile and hot-tear strengths, and resilience of the ash-rubber material, as determined in laboratory tests, were significantly less than that of comparable rubber. The material appeared unsatisfactory for automobile and truck tire manufacture, but might prove suitable as a filler in other rubber goods. Raw fly ash could not be satisfactorily compounded with rubber.

Jan 1, 1972

By John B. Umhau

[' is ann.tal surve:' gives sta.tistical data regC:ll~dirg rims.ry and feCOA-dUTY or ~cra:p tin used in thL United States by industries anc. includcc dc..ta l' is ann.tal surve:' gives sta.tistical data regC:ll~dirg rims.ry and feCOA-dUTY or ~cra:p tin used in thL United States by industries anc. includcc dc..ta ]

Jan 1, 1938

By F. A. Rutledge

The Bureau of Mines Investigated the Copper Bullion claims at Rua Cove on the east coast of knight Island in Prince William Sound, Alaska, during November-December 1948 and March-April 1949. This project was part of the Bureau of Mines program for developing critical and strategic minerals in Alaska, Mineralization at the copper deposit on the Copper Bullion group of claims is mainly pyrrhotate and chalcopyrite, confined to a northeast-trending shear zone in the greenstone 2,000 feet northwest of Rua Cove. The property has been partly developed by two adits, by a number of crosscuts from the upper adit, and by several diamond-drill holes.

Jan 1, 1953

By Launa G. Mallett, Kathleen M. Kowalski, Michael J. Brnich

The characteristics of leaders under the duress of an emergency are important in the development of emergency planning, training, and in the management of an actual emergency. Knowledge of human behavior is an important component in the formation of emergency strategies. The U.S. Bureau of Mines analyzed the leadership behavior in three underground mine fire escapes. The subjects described their escapes during open-ended interviews. Data were coded according to: (1) evidence of leadership behavior, (2) evidence of lack of leadership behavior, and (3) characteristics of the individual in each group who led the subjects out of the mines. This paper discusses the profile of six individual leadership characteristics which emerged from the data.

By R. V. Ramani, S. Shankar

"The phenomenon of re-entrainment is seen in environments such as sand dune formation, soil erosion, fugitive dust emission and the spread of radionuclides from accidents involving nuclear weapons. A thorough review of existing literature reveals that work on re-entrainment of dust in mine atmospheres is scant. The present study was undertaken as a part of ongoing research at the Generic Mineral Technology Center on Respirable Dust at the Pennsylvania State University on the development of methods to predict ambient dust concentrations in mine atmospheres (Ramani, 1983). The contribution of re-entrainment to the spatial and temporal concentration of dust in mine airways is being studied. The research has included wind tunnel and in-mine studies.A set of seven experiments was performed under controlled conditions in the US Bureau of Mines' Lake Lynn Laboratory mine. Two types of source coal dust, anthracite and bituminous, were subjected to various airflow rates and were subjected to walking by two different individuals. Six sets of instruments were used along the test section for sampling airborne particles. The average air velocity just above the coal dust bed varied between 2.1 to 3.2 m/sec.Due to re-entrainment as a result of the airflow conditions, the average respirable dust concentration in the center of the mine airway increased to 0.09 mg!m3 (standard deviation= 0.03 mg/m3)from an initial value of 0.02 mg/m3. The concentration of all (total) airborne dust increased to 0.17 mg/m3 (standard deviation = 0.10 mg/m3) from an initial value of 0. 02 mg/m3. The action of people walking, however, caused higher amounts of re-entrainment. The average concentration of respirable and total dust at the center of the mine airway increased to values of 0. 28 mg/m3 (standard deviation of 0.12 mg/m3) and 1.53 mg/m3 (standard deviation of 1.0 mg/m3), from initial values of 0.03 and 0.05 mg/m3, respectively. Jr was observed that the dust concentrations were much higher near the floor, immediately at the end of the coal-dust bed.Depending on the level of activity and the amount of dust deposited in the mine airways, re-entrainment may become an important source of airborne dust in areas away from the point of actual mining."

Dec 1, 1996

By Gregory M. Molinda

The Bureau of Mines conducted an investigation into the occurrence of outbursts of salt known to be responsible for explosions, fatalities, and damage in domal salt mines. The purpose of the investigation was to develop a basis for predicting these outbursts based on geologic and associated physical properties of salt. The investigation was conducted at the Cote Blanche salt mine in southern Louisiana. Because outbursts are the primary mode of methane emission into the mine, more than 80 outbursts, ranging in size from 1 to 50 ft in diameter have been mapped. These outbursts generally are aligned and elongate parallel to the direction of salt layering. More than 200 salt samples, both random and selected, were tested for methane content. It was found that outburst zones are well correlated with high methane content. Detailed mapping also revealed that the zones are well defined, with salt crystal size abruptly increasing upon entry into the zone. The intensity of folding and kinking of the salt layering within the outburst zone also appears to increase. An interbedded sand layer occurring throughout the mine does not appear to be a significant source of methane. However, fine-grained salt may be related to outburst occurrence.

Jan 1, 1988