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

4. Guidelines for Implementing the Emergency Escapeway Standards for Metal and Nonmetal Mines The technical discussion of each escapeway component precedes the specific guidelines for the component. Generally, the technical discussion provides the background and reasoning behind the guidelines. Section 5 is a discussion of general escapeway requirements, including the escape route, fire retardants, warning systems, ventilation systems, escapeway signs and signals, auxiliary transportation and fuel storage. The discussion is followed by a list of guidelines pertaining to the escapeways. Section 6 is a summary of the computer simulation of an escapeway system for Mine "C". A complete documentation of the simulation is included in Appendix A and B. Section 7 covers emergency hoisting requirements and concludes with the guideline, for emergency hoists, their inspection and use. Section 8 is a discussion of refuge chambers and life support and is concluded with guidelines for the application o f this equipment.

Jan 1, 1976

Provide minx operators with means for evaluating dust generation and bit wear effects on Production without costly and extensive underground testing. Approach Develop personal-computer-based cutting system models that will simultaneously evaluate machine, Coal seam, and mine-operator-controlled parameters for their interactive effects on dust generation, bit wear, and Production by either a longwall shearer or a continuous miner. How It Works CSM Programs have been developed to analyze relative dust generated by a double-drum, ranging arm, longwall shearer and a continuous miner. These interactive programs Provide relative dust, culling forces, and production values for any given set of mining machine parameters, specific seam conditions, and operator-controllable parameters. Expanded versions of each program provide a dynamic evaluation of the effects of bit wear, over time, on production.

Jan 1, 1989

By C. M. Mason

A method for evaluating the relative incendivity of detonating cord in natural gas-air mixtures was developed. The method consisted of firing short lengths of cord in bundles to determine the number of strands per bundle which would ignite natural gas-air mixtures 50 percent of the time in the 45-cubic-foot gallery of the Bureau of Mines. The relative efficiency of a flame quenching agent, potassium acid tartrate (KHT), when incorporated in both the pentaerythritol tetranitrate (PETN) core and the polyethylene sheath, was explored. The effects of sheath thickness, sheath composition, core weight, and core composition were evaluated. The bundle method established a quantitative scale for evaluating the relative incendivity of cords. The relative incendivity determined by the bundle method was then compared with the incendivity of 100-foot lengths of detonating cord when initiated in 8 percent natural gas in the 640-cubic-foot gallery of the Bureau of Mines.

Jan 1, 1968

Develop new technolgies and techniques which enable recovery of strategic and critical minerals such as cobalt from domestic resources, thereby easing the U.S. dependence upon foreign producers for these valuable commodities. Approach The Bureau of Mines, through research, developed a process which uses mineral beneficiation techniques to recover cobalt-rich products from Missouri lead ores. Before development of this process, cobalt was lost as an impurity in the copper, lead, and zinc concentrates and in the mill tailings because the technology to recover it with minimum impact on present production did not exist.

Jan 1, 1989

By Fred N. Kissell, J. E. Matta, J. C. LaScola

The Bureau of Mines made laboratory absorption measurements on oil shale samples, which showed that the amount of methane absorbed is proportional to pressure and oil yield, and can be much larger than would be predicted based solely on porosity. Oil shale cores collected in the field were also measured for their gas content using the Bureau of Mines direct method, Cores taken from deep locations and far from outcrops yielded more gas than cores from shallower locations or at outcrops, when taking into account variations in oil yield, and all data indicate that oil shale mines that are both deep and far from an out- crop will emit low levels of methane gas.

Jan 1, 1977

By Thomas V. Falkie, R. Venkataramani

Hand portable truck axle scales were purchased from the Martin¬Decker Company, Santa Ana, California, for weighing the rubber-tired mine shuttle cars. The scales consisted of two hydraulic load-pads, measuring 4" thick, and 21" long by 13" wide at the pad surface and one totallizer-dial indicator unit. The development of a technique to install the scales effectively for shuttle car-weighing followed an evolutionary process. The setup which finally proved to be effective entailed countersinking and level¬ling the load pads in the floor on the shuttle car trackway such that the tops of the pads were three inches below the floor level. A plat¬form consisting of two braced side-by-side 3" x 8" lumber planks was made. The platform was placed across the load pads with six inches of overlap on each side to provide room for imperfect tracking of the shuttle car. Additionally, 3" x 8" lumber planks were imbedded across the runway immediately behind and ahead of the platform. These auxili¬ary planks were firmly braced into the floor by vertical posts or jacks set against the roof; the planks constituted a stable approach platform to enable the shuttle car to roll unimpeded onto the scale platform in either direction of travel. Figure 22 shows this arrangement in detail. The setup of the scales was done during non-production hours prior to the first working shift of the week. This task took seven to twelve hours with two men. During the actual weighing experiment, the following limitations were realized. 1. Delays will be introduced into the cycle of operations because the shuttle cars must be stopped and positioned on the platform. However, these delays can be held to a minimum, time wise, as the

Jan 1, 1972

By Launa G. Mallett, Charles Vaught, Michael J. Brnich

Beginning in 1991, scientists at the Pittsburgh Research Laboratory recorded interviews with individuals who are recognized as experts in mine emergency response. These 30 veterans related stories and observations from events experienced during as many as 47 years of response activities. Overall, the response veterans averaged 29 years of mine emergency response experience and 35 years of mining experience. Interviewees included representatives from mining companies, the United Mine Workers of America, and State and Federal agencies. Most of their comments dealt not so much with technical aspects of particular mine emergency responses, but rather the human side of more general topics, including preparedness, experience, people on-site, mine rescue teams, and decision-making. An analysis of their interviews provides an overview of lessons learned on-site at some of the largest mine disasters since the mid-1940s. This knowledge was gathered so that it could be provided to today's miners and to tomorrow's emergency response personnel. It is expected that the collective wisdom obtained can be used to help train new responders and guide those decisions that will have to be made on the scenes of future events.

Jan 4, 2004

By C. B. Manula, R. L. Sanford, R. A. Rivell

Data input is divided into three divisions for discussion purposes below. These divisions are: a) Information Retrieval and Control Options; b) Gaming Options; and c) Descriptive Parameters. The data input for model application, which is listed in Appendix B, is segmented to show the location of these divisions. In actuality, however, these divisions form a continuous data file. Each 80 character record of data input is edited by an alpha¬numeric editing routine which permits the format free numerical speci¬fication in most data divisions. The editing routine searches each record for numeric types and when found, converts these numbers into computational forms. The Fortran convention of decimal and integer numbers is not used by the editor so that a number may appear on the data record in either form desired by the user. Since the editor seeks only numeric types, the input records may be freely commented and identified with alphabetic letters (A - Z). One or more input records may contain only commentary information or be entirely blank. On the other extreme, any data record may contain up to 40 numeric elements, each separated by a blank space. The application of this capability can be seen by reference to the data. Information Retrieval and Control Options The information retrieval options specify the detail of infor¬mation required to be printed. These have been placed in a separate data division, identified on the data record by option name for use

Jan 1, 1974

By Robert P. Vinson, John C. LaScola, Fred N. Kissell, Edward D. Thimon

The face ventilation measurement method developed by the Bureau of Mines involves releasing a small volume of tracer gas (SF6) on the off-curtain side of the working face at the start of the mining cycle. At the same time, gas bottle samples are taken in the immediate return airway. The gas samples are analyzed, and a curve is drawn of SF6 concentration versus time. From this curve, the percentage of gas removed per time is calculated. A curve showing a high percentage of the tracer gas removed in a short period would represent a well-ventilated face. The face ventilation measurement method was tested in a full-scale mine entry model. Subsequently it was used underground to evaluate the spray-fan ventilation system and in an MSHA test facility to test machine-mounted scrubbers. The method was shown to be a simple and effective way of evaluating face ventilation systems.

Jan 1, 1980

By Kathleen M. Kowalski, Audrey Podlesny

The Maslach Burnout Inventory (MBI) was administered and scored for 154 Mine Safety and Health Administration (MSHA), U.S. Department of Labor, employees who serve as accident investigators for serious accidents and fatalities as part of their job duties. The subjects responded anonymously during a workshop on stress. The subjects consisted of randomly selected individuals, representative of locations across the country and representative of all mining commodities: coal, metal, nonmetal, stone, and sand and gravel. The Maslach Burnout Inventory assesses three aspects of experienced burnout: emotional exhaustion, depersonalization, and reduced personal accomplishments. The average results of the scores for each of the three subscales fell in the moderate range for the study group of MSHA accident investigators. The scores within the moderate range show that the subject population was at the lower end of the range for emotional exhaustion and depersonalization, tending toward a lower burnout risk, while the group evidenced a lower sense of personal accomplishment in their jobs, indicating a higher risk for burnout. It is concluded that overall this group is at moderate risk for burnout, and the authors recommend follow-up with this population.

By E. C. Bennett

"INRTODUCTIONVarious methods of making leakage tests have been tried during a study of losses in the transmission of natural gas. This work has been carried on by the Bureau of Mines in cooperation with the Natural Gas Association of America. Results of torts show that the ""shut-in -pressure-drop"" method described by Rawlins is the most accurate and reliable; therefore its use is recommended. This paper describes a graphic method for computing the rote of leakage from the fall in pressure and change in temperature determined by the ""shut -in pressure-drop"" method of testing.METHOD OF MEASURING PRESSURE DROPThe gas is ""shut in"" line to be tested and is not allowed to escape except through existing leaks. The leakage causes the pressure in the line to fall. The charge in pressure is obtained with a dead weight gage. Approximate results may also be obtained from readings on a good spring test gage. Numerous tests show that the dead weight gage is more sensitive to small changes in pressure than spring gages.The temperature of the gas in the line is observed simultaneously with each pressure reading. Temperature changes affect the pressure exerted by a given quality of gas ""shut in a line, end since the rate of leakage from a closed system is directly proportional to the rate of pressure drop, fluctuations in temperature must be considered."

May 1, 1926

By Mark A. Ackerson, Kenneth E. Hjelmstad

An ideal fire warning alarm system for underground mines would be low cost, convenient, fast, reliable, and able to warn all underground workers. Present warning systems, such as phones, messengers, and stench, fail one or more of these criteria. The U.S. Bureau of Mines may have devised the ideal system. The one way communication system employs a large loop antenna and transmitter to create a 630 hertz (Hz) electromagnetic field to send information through-the-earth to cap lamp battery mounted micro- receivers worn by underground miners. Field tests of prototype equipment in 1986 resulted in through-the- rock signal transmission of over 762 m (2500 ft). Subsequent hardware upgrades for more recent tests resulted in transmissions of over one mile. Recently developed receiver circuitry employs phase- locked-loop detection circuitry responsive only to a specific series of pulses of given time duration, that eliminates false alarms from electromagnetic noise emitted by mine equipment, power lines, or lightning. A multichannel system can relay standard messages to miners

By Edward A. Mihok

Laboratory batch-flow tests conducted on a highly ferruginous acid mine water with an activated carbon showed that ferrous iron is rapidly oxidized. This indicates that air oxidation of ferruginous acid in mine waters is catalyzed by activated carbon. The ferrous iron content of an acid mine water flowing through an aspirated activated carbon column was reduced from about 700 to about 10 parts per million in less than 1 minute. Highly efficient ferrous iron oxidation was achieved by conditioning the activated carbon by repeated treatment with acid mine water and air. The reaction proceeds rapidly in the acid environment (pH about 2.5) engendered by ferrous iron oxidation. The activated carbon was used repeatedly with little loss in efficiency, no discoloration, or solids deposition. In these batch tests, about one-third of the iron was adsorbed by the carbon, but with continuous flow, little iron adsorption is expected. Incorporating a catalytic oxidation step in the treatment of acid mine waters containing ferrous iron would greatly facilitate neutralization--precise control of pH, lower reagent costs, elimination of aeration equipment, and smaller holding ponds.

Jan 1, 1969

By Wing G. Agnew, John A. Johnson

"INTRODUCTION This paper is one of a series being published by the Bureau of Mines pertaining to an investigation on the use of stemming in metal mines now being conducted at the Mount Weather Testing Adit. Its purpose is to compare the amount of dust and gases produced as a result of blasting charges of dynamite (1) in drill holes, (2) in bombs, and (3) in mud-cap or adobe shots.ACKNOWLEDGMENTSValuable assistance and advice on stemming were given by members of the staff at the Bureau of Mines, as acknowledged in previous publications. 4/TEST PROCEDUREThe results used for comparison in this report are from dust and gas samples taken after blasting (1) four regular test rounds with no stemming, (2) five bomb shots, and (3) two mud-cap or adobe shots."

Dec 1, 1942

By George S. Koch

In preparing diamond-drill core samples for assay at the Homestake mine, Lead, S. Dak., 5-foot intervals of core are processed through three stages, crushing, grinding, and pulverizing, and portions of the core material are discarded after splitting at each stage of preparation. Then two 1-assay-ton fractions are taken from the pulverized material and assayed. This report investigates alternative methods of sample preparation. The consequences of crushing, grinding, and pulverizing all rather than part of the core are appraised through the statistical analysis of assay results from 118 5-foot intervals of core. Evidently, a substantial improvement in precision at small additional expense is obtained by grinding most or all of the core before splitting. Pulverizing all of the core would be desirable only if doing-so would cost less than assaying five random splits from each interval. Graphs and tables detail appropriate procedures to obtain specified precisions. The experimental design and methods can be applied to similar problems in preparing core and other geological samples.

Jan 1, 1972

By A. W. Hall

A neutron meter was developed for monitoring the sulfur content of coal streams. Neutrons from 80 micrograms of californium-252 penetrate the coal, producing thermal neutrons that are captured by atoms of elements present in the coal. The excited atoms emit prompt gamma rays with energies characteristic of the capturing element. These gamma rays are detected with a 6-by 7-inch sodium iodide detector and processed by electronic equipment to produce a gamma ray energy spectrum of the elements. Tests of the meter at a commercial coal preparation plant showed that sulfur in moving coal can be determined to a precision of 0.05 percent sulfur within 2 minutes. Based on this report by the Bureau of Mines, reliability of the coal-handling system proved inadequate for long-term operation, however, and improvements are planned.

Jan 1, 1975

By Ben A. Kornhauser

Petroleum production was the principal component of the mineral industry, followed by cement production and some salt output. The French Central Fund for Economics Cooperation loaned $9.15 million2 to the Communauté Electrique du Benin (CEB), which served Benin and Togo, toward financing the construction of a dam on the Mono River at Nangbeto, Togo. The dam was to supply hydroelectric power to reduce the energy dependence of the two countries and to irrigate crops. Nine other international financial organizations, including the International Bank for Reconstruction and Development (World Bank). the African Development Bank, the Arab Bank for African Economic Development, and the French Aid and Cooperation Fund, contributed to the estimated $140 million cost of the dam. The CEB also was to contribute to the financing. Contracts amounting to $60 million already had been awarded to West German and Canadian firms. The dam was expected to be completed in 1987.

Jan 1, 1986

Reduce respirable dust in coal preparation plants. Approach Survey a representative sample of coal preparation plants to (1) determine the dust problem extent, and (2) evaluate practical dust control techniques. Coal Preparation Plant Survey Results Of the approximately 500 coal preparation plants in the United States, 18 plants in six States were randomly selected for survey. The raw hourly capacities ranged from 250 to 1,250 tons, plant construction dates ranged from 1037 to 1982, and usually 3 to 10 workers were required per shift. Respirable dust concentrations within the plants surveyed ranged from very good (less than 1 mg/m') to very poor (14 mg/m3). No relationship was found between dust concentration and age or capacity of the plant. Six of the plants had long-term respirable dust concentrations between 7 and 14 mg/m' in specific areas; six had concentrations between 2.2 and 6.2 mg/m'. Except fur ventilation, only 4 of the 18 plants used operating dust control devices with mixed effectiveness.

Jan 1, 1989

Predict the cumulative hydrologic impact of mining on the environment. Approach A comprehensive set of computer models has been developed to predict the impact of mining on ground water. Mine inflows, drawdowns in aquifers, and ground water quality can be predicted. How It Works The Prickett-Lonnquist finite-difference groundwater model was specially modified for the hydrologic problems of mining. This model, developed at the Illinois Water Survey in the 1960's,

Jan 1, 1982

By Sathit Tandanand

Geological differences among various coalfields restrain the applicability of subsidence prediction using empirical approaches previously developed. The Bureau of Mines assessed data collected from 16 longwall panels in the Northern Appalachian basin. Attention was focused on the effects of rock lithology, excavation width, and panel depth on the subsidence factor. The results show that the subsidence factor can be expressed in terms of the width-to-depth ratio by a simple exponential equation, which has a coefficient tentatively considered as the subsidence index. This index varies with the lithology of a particular site, and can be expressed in terms of percent distribution of weak and strong rocks in the overburden.

Jan 1, 1982