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By H. F. Weaver

The 18th National First-Aid and Mine Rescue Contest was held in the Memorial Auditorium, Buffalo, New Vork, October 5, 6, and 7, 1959. The meet was sponsored by the Federal Bureau of Mines and the Joseph A. Holmes Safety Association, in cooperation with State mine inspection agencies, management and labor of the mineral extractive industries, and other safety minded groups. The Arrangements Committee, as authorized by the General Committee, made a11 the necessary arrangements for conducting the 1959 contest. Members of the Arrangements Committee were: Harry Gandy, Jr. (chairman), National Coal Association; James B. Benson, Southern Coal Producers' Association; Charles Ferguson, United Mine Workers of America; George C. Trevorrow, Bituminous Coal Operators' Association; and James Westfield, Federal Bureau of Mines.

Jan 1, 1960

The Bureau of Mines has conducted considerable research to improve life support technology for underground mining applications. This proceedings volume presents several new developments that may help increase the chances of mine workers in surviving underground disasters. Several papers address the performance of present self-contained self-rescuers (SCSR's) and provide proposed guidelines for the design and testing of a second-generation SCSR. Improvements In the safety and effectiveness of mine rescue and recovery operations are described, including the design of a low-profile rescue breathing apparatus and a rescue team helmet.

Jan 1, 1987

Determine the effectiveness of remining operations in reducing contaminant load (acidity, iron, and sulfate) of discharges emanating from abandoned surface and underground coal mines. Background Until the implementation of remining initiatives, most States had regulations that held the operator remining an abandoned site responsible for preexisting acid mine drainage (AMD) discharges. For example, if a mining. company wanted to remine an area hydrologically connected to an existing AMD discharge, the company became responsible, as soon as the site was activated, for treating that discharge to meet effluent standards. If the mining operation improved the quality of the discharge, but the discharge failed to meet effluent standards, the company was held accountable for perpetual treatment. Because of this regulation, most mine operators avoided abandoned sites with minable coal reserves and AMD discharges. However, changes in remining legislation allow coal companies to be released from treatment liability as long as the post-remining pollution load does not exceed the pre-remining level. If remining can improve water quality through improved mining and abatement techniques, abandoned mine land (AML) areas that previously were liabilities could become

Jan 1, 1994

By William C. Larson

This Bureau of Mines report discusses uranium in situ leach mining in the United States to acquaint the public with an overview of this emerging mining technology. This report is not intended to be a technical discussion of the subject matter, but rather should be used as a reference source for information on in situ leaching. A list of in situ leaching publications is included as well as engineering data tables for almost all of the active pilot-scale and commercial uranium in situ leaching operators. These tables represent a first attempt at consolidating operational data in one source, on a regional basis. Additional information is given that discusses the current Bureau of Mines uranium in situ leaching research program. Also included is a listing of various State and Federal permitting agencies, and a summary of the current uranium in situ leaching operators. Finally, a glossary of terms has been added, listing some of the more common terms used in uranium in situ leach mining.

Jan 1, 1978

By P. Coleman, J. C. Kerkering, S. Iverson

Fault tree analysis is a systematic safety analysis tool that proceeds deductively from the occurrence of an undesired event (accident) to the identification of the root causes of that event. One recurring mine safety problem—a dozer falling into a void over a drawpoint on a coal surge pile—was analyzed using available, inexpensive fault tree programs on a personal computer. The analysis identified basic and intermediate events that led to the burial of the dozer and graphically depicted the interrelationship between these various subordinate events as well as the various chain of events leading up to the primary event. A sensitivity analysis on these probabilities showed which events had the greatest influence on dozer burial in a coal surge pile.

By F. E. Block

This investigation was made as part of a larger program to develop basically new methods for preparing yttrium metal in high-purity form. It was performed under a cooperative agreement between the U.S. Atomic Energy Commission (AEC) and the Federal Bureau of Mines. Laboratory-scale tests were made to devise methods for preparing high-purity, anhydrous yttrium trichloride, for reducing the yttrium trichloride with sodium or lithium, and for consolidating the resulting yttrium sponge into ingots.

Jan 1, 1960

By C. S. ROBINSON, T. M. Romslo

This investigation was conducted jointly by the Bureau of Mines and the Geological Survey to obtain further information on the source and economic possibilities of the copper mineralization exposed on the Copper Giant group of claims, Ajo mining district, Pima County, Ariz. The Copper Giant group of claims was first brought to the attention of the Bureau of Mines by Joseph Hunter (deceased), Phoenix, Ariz., part owner of the claims. In December 1942 these claims, and an adjoining group, were investigated by T. C. Denton, mining engineer, formerly with the Bureau of Mines, and Nels P. Peterson, geologist, Federal Geological Survey. It was concluded the area could not be considered as a source of copper for immed- iate emergency needs and that further investigation of the area, at the time, was not warranted. In the spring of 1948 the lessee, J. H. Greenway Albert, requested Bureau of Mines assistance in developing the property. J. H. Hedges, former chief, Tucson Branch, Mining Division, and Lincoln A. Stewart, mining engineer, Bureau of Mines, made a cursory examination of the property and noted that at numerous places, low-grade copper mineralization appeared on fractures and bedding of the Locomotive fanglomerate and Ajo volcanics, which are thought to be of Tertiary age. During the period of May 11 through 14, 1949, Bureau of Mines engineers3 mapped and sampled two areas of mineral- ization. On June 2 and 3, 1949, the areas selected by the Bureau and three other nearby mineralized areas were investigated by C. A. Anderson and R. S. Cannon, Jr., of the Federal Geological Survey. As a result of these examina- tions, further investigation of certain areas was believed to be merited. The Copper Giant area was selected as the most favorable in which to carry out exploratory and development work. The field work on the project was started in October 1949 and completed in December 1949. It consisted of road building, trenching, sampling, topo- graphic and geologic mapping, diamond drilling, and logging of core. Samples taken on the project and during preliminary examinations totaled 64, of which 63 were surface samples. Diamond drilling, started October 10 and completed December 7, consisted of two holes for a total depth of 1,542 feet.

Mar 1, 1952

To suppress the natural bacterial action in acid mine drainage (AMD), the major contributor to acid formation. Approach Recycle partially-treated affluent back to the source of AMD within a mine, or to the coal or coal-waste stockpile. This effectively eliminates any further biologically-promoted AMD by inhibiting catalyzed weathering or oxidation by acid-forming bacteria. How it Works AMO-type effluents can be largely reduced by "recycling" the acidic outflow back to the source of AMD within a mine or to the Input side of a waste pile to percolate through the reactive pyrite and bacteria mixture. The bacteria in the cell thrive on the oxidation of ferrous to ferric iron through the electron transfer, Fe2 +[=]Fe3 + + e. Its reaction product [s, therefore, essentially ferric iron. While small quantities of Fe3 + will not interfere with the exponential multiplication of the bacteria

Jan 1, 1982

By B. R. Mohal, F. F. Aplan, S. Chander

"ABSTRACTThe wetting behavior of coal has been determined in the presence of nonyl and octyl series of nonionic surfactants containing polyethoxy groups of different sizes. The wetting behavior was determined by a modified Walker technique and contact angle measurements. The results show that the wetting rate of coal varies with coal rank, structure of the hydrocarbon chain and number of ethoxy groups in the hydrophilic group of the surfactant. A close relationship has been observed between the wetting rates and the short-time advancing contact angles.INTRODUCTIONNonionic surfactants are used in many applications to improve wettability of solids. They can be used as dispersing agents [ 1 ] or dust suppressants [ 2-5 ] and to control the flotation, flocculation, filtration and flowability of particulates. This study was undertaken to study the effect of a series of nonionic surfactants on the wetting behavior of coal. Two series of surfactants, namely, ethoxylated nonyl and octyl phenols were used. The nonyl phenol series contains a linear hydrocarbon chain containing nine carbon atoms ( CH3( CH2 )8-C6H4,- ( OC2H, ) n, where n is the number of ethoxy groups) . The octyl phenol series contains a branched hydrocarbon chain containing eight carbon atoms ( ( CH3 ) 3CCH2C ( CH3)2-C6H4- ( OC2H4) n ).Initial wetting rates — modified Walker techniqueWalker et al. [ 6 ] developed a sink test to determine the wettability of coal particles. In this technique, coal particles are dropped individually onto the surface of surfactant solutions of different concentrations, and the most dilute concentration in which coal would sink ""instantaneously"" is determined. This technique is a variation of a procedure initially developed by Draves and Clarkson [ 7 to determine the effect of surfactants on wettability of cotton fibers. In this procedure commonly known as the Draves test, the concentration of a surfactant required to give a 'sink time' of 25 s is determined.Other investigators have used slight variations of the Walker method to study the wetting of fine particles [ 8-12 ] , by measuring the time for wetting a given amount of powder. There are differences in the manner in which the time of wetting is measured, however. Some investigators measure the time for the last trace of coal to disappear [ 8,11 ] whereas others determine the time for the vast majority of particles to sink [ 10 ] . Some investigators report a wetting rate [ 11 ] which is a value calculated on the basis of the time for the 'last traces of particles to sink'. The differences in choice of criterion for wetting can result in different values for wetting rates as illustrated in Fig. 1 which is based upon our measurements of the amount of powder wetted as a function of time. The procedure for wetting rate measurements is described in the next section. The technique in which time for disappearance of the 'last traces of particles' is determined gives the smallest value for the wetting rate, while the technique in which the time for wetting of the 'vast majority' of particles is determined will give intermediate rates. The terms 'last traces of particles' and 'vast majority of particles' are usually not defined explicitly and can lead to large differences in wetting rates measured by different investigators. Since our measurements show that the wetting rates for an assembly of powder decreases with time, we have used the initial wetting rates to compare the wetting behavior of coal in solutions of different surfactants."

Mar 1, 1989

By A. Wahab Khair, N. P. Reddy

"Abstract. This paper attempts to characterize coal breakage due to the action of a continuous miner. Coal blocks with an approximate dimension of 45.7 cm x 38.1 cm x 15.2 cm (18 in. x 15 in. x 6 in.) were first subjected to confining pressures equivalent to in-situ conditions. Then the blocks were cut along the face/butt cleat direction by the cutting head of a specially designed unique automated rotary coal cutting simulator (ARCCS), simulating the action of the continuous miner in underground coal mining. During the tests under a particular set of in-sit and operating parameters a number of other para¬meters such as 1) penetration of bit into coal, 2) penetration resistance (thrust and cutting pressures), 3) rotating velocity of cutting head, and 4) acoustic emission activity in the coal block were monitored. After each cutting cycle the fractured surfaces were photographed and a velocity survey was conducted by using a sonic technique. At the end of each experiment, the coal fragments were collected in bags using a vacuum cleaner. These fragments were then sieved for size distribution analysis.INTRODUCTIONThe Federal Coal Mine Health and Safety Act of 1969 was enacted to emphasize to coal operators that the airborne respirable dust should not exceed 2 mg/m3, thus reducing the incidence of coal workers pneumoconiosis.Dust control techniques such as conventional water sprays and dust collectors are only partially effective and require additional equipment expenditures. A more authentic approach would be to reduce respirable dust at the source the continuous mining machine cutting head, where the fragmentation process occurs. Improving the fragmentation process by characterizing the coal breakage will not only reduce respirable dust at the face, but it will also decrease the amount of respirable dust that is liberated during the secondary handling.Fragmentation of coal can be expressed as a function of three major groups of parameters; namely, 1) coal properties, 2) in-situ conditions and 3) operating parameters. This paper deals with the characterization of coal breakage along both face/butt cleat direction as a function of machine operating parameters such as rate of advance, angle of attack, bit configuration, bit lacing (spacing and pattern) and bit speed at various equivalent in-situ pressures."

Mar 1, 1989

By R. Hogg, T. F. Dumm, L. G. Austin, M. Yekeler

"Dedicated to Professor Kurt Leschonski on the occasion of his 60th birthdayAbstractThe kinetics of batch grinding quartz from a feed of 600 by 425 Jim to a product of 80% less than 10 µm have been determined using screening and laser diffractometer sizing for size analysis. The specific rates of breakage decreased by a factor of about three when the material became less than about 100 µm in size, but the primary breakage distribution function also changed to give proponionately more fine material, so that the grinding efficiency expressed as the development of surface area (B.E:T.) per unit of energy input did not decrease. Analysis of the shape of the particles in the 2S x 38 µm size range showed that particles of this size produced by roll crushing or by 8 minutes of grinding of a 42S x 600 µm feed were not different but at long grinding times the particles were rounded. This suggests that the breakage mechanism changes to give more chipping and abrasion and less disintegrative fracture. As the material approached the ultrafine size range it adhered to the mill case and there was no further size reduction. However, a technique for striking the mill case to dislodge the particles was successful in allowing further grinding to 400Jo by weight less than 2 µm.1 IntroductionIt has long been known that it is difficult to accomplish ultrafme grinding in a tumbling ball mill. It has been reported [12, 13] that there is no further size reduction after some hours of grinding cement clinker in laboratory ball mills. Austin and Bagga (1] and Shah and Austin [16] have given an analysis of the kinetics of dry grinding in a laboratory ball mill, introducing the concept of a slowing-down factor K, which is the ratio of the specific rates of breakage at some long time of grinding to the normal specific rates of breakage. They showed that this factor decreased as fine material accumulated in the mill charge. Cottaar and co-workers [8-10] showed that the movement of solid in a dry laboratory ball mill was influenced by the fineness of the solid and by the presence of air, and that evacuation of air from the mill caused particle sedimentation and low rates of breakage.The concept of the slowing-down factor has also been used in wet grinding [17, 18]. At very .high slurry concentrations it appears to be correlated with a steady decrease of mill power caused by the build up of a layer of deposit sticking to the mill case. This reduces the effective mill diameter and, eventually, the balls start to adhere in the layer and centrifuge. A decrease of mill power always indicates less lifting and tumbling of the media and, hence, less breakage. However, slowing-down of breakage rates was also observed at lower slurry concentrations where there was no change in mill power."

Jan 1, 1990

By R. V. Ramani, J. M. Mutmansky, J. Qin, J. Organiscak, R. Bhaskar

"The results of a two—year research study into the relationship between quartz dust levels in host material and in respirable dust in continuous mining sections are presented in this paper. The experimental design and sampling procedures for underground data collection are outlined. The sample analysis procedures for quartz determination, the ¬analysis results and conclusions of the study are discussed.The results of the study indicate that the quartz contents of the airborne dusts are generally higher than those in the host material and bulk samples; and the quartz content increases with decreasing size of the airborne dust. The source for quartz appears to be the roof and the floor materials rather than the coal seam itself. It also appears that the material containing quartz may be breaking into a different size distribution than coal.INTRODUCTION Without doubt, the potential for permanent and severe health damage exists due to respirable dust in the work environment. The attention directed at the reduction of respirable airborne dust to levels below those specified in the law and the achievements to date in meeting these standards are but a reflection of the recognition by many parties government, industry, and labor - of this potential and the need to reduce it.The ambient dust standard in underground U.S. coal mines (2 mg/s3) has a qualifier (Code of Federal Regulations, Title 30, Part 71.101) to determine an applicable dust standard when a respirable dust sample contains more than 5% quartz. This standard is frequently referred to as the ""reduced standard."" The reasoning behind the reduced standard is the relative toxicity of the quartz dust compared to that of pure coal dust. As the quartz levels in samples increase, the applicable standards become more stringent and maintaining the workings in compliance becomes increasingly difficult.The number of underground work locations operating under the reduced standards has shown a dramatic increase since 1980 (Figure 1). For comparison purposes, there were no mining entities operating on reduced standards prior to 1977. The emergence of this problem, which affects the health and safety standards on one hand and creates severe compliance problems on the other, has been rapid."

Jan 1, 1990

Objective As mines become safer and disasters fewer, a time may come when no employees in the mining industry have any practical experience in managing a mine emergency. To fill an emerging gap in mine emergency response training, a multidisciplinary team of researchers and computer programmers from the NIOSH Pittsburgh Research Laboratory has developed an intervention for mining personnel who would be in leadership positions in the command center during emergencies. It is called MERITS, a computer-based emergency simulation exercise. MERITS is short for "Mine Emergency Response Interactive Training Simulation." It provides trainees an opportunity to gain command center experience during a simulated underground coal mine emergency. MERITS allows trainees to practice information gathering, situation assessment, decision-making, and coordination skills without risk to personnel or property. Individuals representing mine emergency response personnel, various State safety officials, and private mine management from three States have participated in MERITS training. What Is MERITS? MERITS is an extension of previous work that compiled a knowledge base relevant to mine disaster management via interviews, analysis of literature, reviews of past events, and observations of mock mine disasters. Findings from prior research found a need for an alternative method of command center training. This new computer simulation is being used to train emergency command center personnel to effectively manage an underground mine fire. Modeled after training simulations developed for other industries (e.g., to address nuclear accidents, chemical spills, evacuations, etc.), MERITS simulates underground and surface events related to the disaster. It exposes the user to events that typically occur during a mine emergency, such as lack of information and miscommunication. It also presents trainees with issues that must be addressed, such as making provisions for briefing news media and victims' families, ordering needed supplies, interfacing with Government enforcement agencies, and housing mine rescue teams. The outcome of the scenario is determined by the users' decisions and their emergency response plans. Field Results Field testing of MERITS was conducted with eight full-day training sessions at four different locations in Colorado, Pennsylvania, and West Virginia. These field tests benefited from the knowledge and experience of State of Pennsylvania inspection officials, representatives of the United Mine Workers of America(UMWA), and private mine management who served as trainees for the MERITS training sessions. Trainees self-reported an average of20 years of work experience in the mining industry. All trainees had participated in Mine Emergency Response Development (MERD) training exercises, and many had been involved in real mine emergencies. Trainee evaluation of the MERITS program is summarized below: •Twenty-six of the 27 trainees believed that the MERITS simulation helped them know how to prepare for a real emergency. •Twenty-five of the 27 trainees believed that the storyline for the MERITS simulation was either "very realistic" or "realistic." •All 27 trainees believed that the MERITS simulation helped them learn how to better handle a real emergency. •None of the 27 trainees stated that they were bored during the simulation. After the initial field tests, MERITS was refined and retested during training sessions for individuals from State agencies, the UMWA, and private industry. Mining personnel from underground coal and underground stone mines participated and responded positively to the learning experience. Technology Transfer Industry introduction to the MERITS program will occur throughout 2002. MERITS presentations at the Joseph A. Holmes Safety Association National Meeting in Virginia Beach, VA, in June.

Jun 1, 2002

By Barry Beith

This report details a study which was designed to assess the effect of retroreflective material on detection and form recognition of workers in the mining environment. Further, the study attempted to determine an optimal configuration of retroreflective material with respect to amount and placement on the body to facilitate detection and form recognition. The study involved a one-fifth scale simulation of the perceptual task found in the underground low seam coal mine. Four different configurations of reflective material were presented in various body positions, common to low coal miners, at three different locations in the visual field, i.e., 10, 25, and 45 degrees from focal line-of-sight. All reflective configurations significantly improve detection and form recognition over configuration (cap only) worn by miners. As the amount of reflective material increased, accuracy also tended to increase. Based on the configurations investigated by this study, the Armband configuration (i.e., refectorized armbands, belt, self-rescuer and battery pack) was determined to be optimum. It is recommended that an actual field evaluation be made using the Armband configuration to establish if simulator results are generalizable to the underground mining environment.

Jan 1, 1980

By W. J. Long

The gradual depletion of high-grade mineral deposits and the necessity for development of lower-grade deposits together with the increased demand for nonmetallic minerals has increased the importance of the ore-dressing field during recent years. There is strong need for development of new ore-concentration methods and-machines to keep pace with the constant changing of marketing specifications and requirements resulting owing to the many new uses made of mineral products by the metallurgical industry.

Jan 1, 1948

By N. F. LeJeune, Earl C. Lane

This is the third of a series of reports on a survey of petroleum prod- ucts manufactured on the Pacific Coast from California crude oils. California crudes differ in many characteristics from the petroleum produced in the other parts of the United States, and the claim has been made that some of the present Federal Specifications for petroleum products tend to discriminate against Cali- fomia products. The purposes of the present survey are to determine what par- ticular specification requirements Califomia petroleum products characteristical ly fail to meet, how widely the products deviate from these requirements, and if possible to show whether the fault lies with the specifications or the products, or along what lines investigation to determine this question should proceed. The first report of the series gave the physical and chemical properties of the samples of gasoline and mineral spirits. A second report**, gave the physical and chemical properties of samples of lubricating oils. The present report deals entirely with burning and fuel oils. The refin ing companies have continued their very cordial and helpful cooperation. Seven samples of kerosene, four samples of Diesel fuel and eight samples of fuel oil were obtained. The methods of analysis used are those adopted by the Interdepartmental Petroleum Specifications Committee, published by the Bureau of Mines in Technical Paper No. 323. The specifications used for corparison are those officially adopted by the Federal Specifications Board for the use of the various Depart- ments and Independent Establishments of the Government, effective February 3, 1923, and published by the Bureau of Mines in Technical Paper No. 323, Part 1. Specific gravity, degrees A.P.I., viscosity and other special tests al- though not required by the specifications have been given for comparison. All temperatures are recorded in degrees Fahrenheit. Tables have been prepared giving data on physical and chemical propertios of the individual samples. Before each table the classification and specifica- tions for the particular class of oil considered in the table are given. Follow- ing each table, brief notes show wherein samples deviate from specification re- quirements.

Aug 1, 1923

Improve the safety of mine workers by developing a sensitive ground-fault relay system capable of detecting and isolating low level ground faults and thereby minimize the danger of electrocution. Approach Inadvertent, direct contact with energized conductors in underground coal mines is a major cause of electrocutions. Although relay systems designed to protect workers against such fatal accidents do exist in some industries, there are no effective ground-fault-sensing relay systems that address the special problems presented by power systems designed for U.S. mines. The Bureau of Mines conducted research to design and construct a sensitive ground-fault relay for use with low-voltage, alternating current (ac) mine electrical systems. Such a relay, sensing current leakage or faults in an electrical system, would send a trip signal to a circuit interrupting device which would then shut down power.

Jan 1, 1986

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 J. A. Kost

Contract H0242013 was originally to evaluate through underground tests, water spray systems for controlling respirable dust at the face of a longwall plow. A number of difficulties were encountered which made such an evaluation impractical. The contract was modified to evaluate, in the BCR dust tunnel facility, the live factors believed to affect respirable dust levels. A 60-foot long; plow face mock-up was constructed in the dust tunnel, a facility with controlled airflow and dust concentration. Six types of nozzles were tested with the following parameters: two nozzle orientations, two levels of water pressure, two levels of airflow, and with and without simulated airflow through the gob. Of these factors, the most significant in reducing respirable dust levels was nozzle orientation, where the nozzle directed 45 degrees downstream resulted in 27 percent lower dust levels than those directed 45 degrees upstream (against the airflow). Following in order of effectiveness were the higher water pressure and the lower airflow. All nozzles tested resulted in similar dust reduction, i.e., the type of nozzle was the least significant factor.

Jan 1, 1979

By M. O. Magnuson

As part of an experiment in the restoration of lands strip-mined for coal, revegetation studies were conducted at three backfilled strip-mine sites in north-central Pennsylvania. The sites were subdivided into plots that were given varying amounts of lime and fertilizer. In tests conducted cooperatively with State and Federal agronomy experts, the plots were then planted with a variety of trees, shrubs, and grass-legume mixtures. Initial tree and shrub survival was not appreciably affected by lime and fertilizer applications where the spoil pH was above 4.5. Of 14 species of trees and shrubs tested, Norway spruce, black locust, Japanese larch, pitch pine, and white pine were the hardiest. The ground-cover percentage of grass-legume mixtures in the second growing season was substantially increased by using lime and fertilizer. Mixtures comprised partly of fescue were the most satisfactory.

Jan 1, 1968