Search Documents

By Ralph Husack

The Bureau of Mines investigated the effect of gamma radiation on reactions between Pennsylvania anthracite and fluorine and chlorine. In the tests with fluorine about 90 percent of the coal reacted at 350° C to form volatile products whether or not irradiation was employed. Up to 0.8 ml of liquid products per gram of anthracite was collected. Among the 25 com-pounds indicated by gas chromatography, fluoroform and l,l-difluoroethylene were tentatively identified from their relative retention times and perfluoro-cyclopentane from its infrared spectrum. In addition, a clear, hard, wax, probably a fluorocarbon, was formed at 45° C in both the presence and absence of radiation. With chlorine there was no significant difference due to radiation, and preliminary tests indicated that the chlorine reacted more with the organic matter of anthracite at 200° C than with inorganic matter. At 400° C the results were inconclusive because of excessive corrosion in the reaction vessel.

Jan 1, 1966

By R. R. Hornor, Geo. M. Hunt

The purpose of this paper is to point out some of the benefits and economies to be derived by the better selection , preparation, storage , preservation and utilization of mine timber , and to give some specific information on certain wood preservatives and processes suitable for mine timber preservation . The paper is based largely upon data obtained by actual experimentation and service tests conducted by the U. S. Forest Products Laboratory , Madison, Wisconsin, on wood preservation , covering a period of many years , and upon a field survey during the past summer by one of the mining engineers of the U. S. Bureau of Mines of some of the principal mining districts of Michigan , South Dakota , Montana , and Idaho , in which he made a general ' study of mine timber in metal mines , particular attention "being given to timber decay ; the conditions under which it takes place most actively ; the measures , if any , that are being used to combat it; and, finally, the advantages that might be anticipated in the use of chemically treated timber to prevent decay and thus prolong its life .

Feb 1, 1922

By Steven J. Knoll, Theodore J. Williams, Douglas F. Scott

Highly stressed rock in stopes continues to be a primary safety risk for miners in underground mines because it can result in failures of ground that lead to both injuries and death. Spokane Research Laboratory personnel investigated electromagnetic (EM) emissions in a deep underground mine in an effort to determine if these emissions could be used as indicators of impending catastrophic ground failure. Results suggest that (1) there is no increase in the number of EM emissions prior to recorded seismic activity, (2) some EM signals are generated during blasting, (3) interference from mine electrical sources mask seismic-generated EM signals, (4) EM emissions do not give enough warning (compared to seismic monitoring) to permit miners to leave a stope, (5) the distance an EM signal can travel in the rock is between 18 and 40 m, and (6) current data acquisition systems do not differentiate between EM signals generated from seismic activity and random mine electrical noise. These results preclude monitoring EM emissions as precursors of impending catastrophic ground failure.

By Richard A. Winters

There are no producing or developing mines or active mining claims in the Deschutes Canyon RARE II study area. Only two prospects were found; they have no identified potential for mineral resources. Thin diatomite deposits occur in the Pliocene Madras Formation. Development of sand and gravel deposits in the area could not favorably compete with similar deposits in the surrounding area which are closer to points of use. By mid-1982, active oil and gas lease applications covered about 25 percent of the area, a reduction from nearly 100 percent in early 1981. No holes were drilled for oil and gas exploration. INTRODUCTION Personnel of the Bureau of Mines, Western Field Operations Center conducted a mineral investigation of the Deschutes Canyon RARE II area during the summer of 1982. The area, about 10 mi (16 km) southwest of Madras, Oregon, covers 10,890 acres (4,407 ha) in the Crooked River National Grasslands (fig. 1). The Deschutes River has incised a deep canyon into the north sloping elevated lava plain near the transitional boundary of the High Lava Plains and the Deschutes-Umatilla Plateau geomorphic divisions (Baldwin, 1964, p. 20).

Jan 1, 1983

By F. N. Kissell

The machine-mounted continuous respirable dust monitor (MMCRDM) is a fixed-location area sampling device developed for possible use at the working face of an underground coal mine. This device, based on proprietary technology known as the tapered element oscillating microbalance, has evolved over the past eight years through a cooperative effort of the former Bureau of Mines, MSHA, and the Rupprecht & Patashnick Company in Albany, NY. The capability to measure respirable coal mine dust levels on a continuous basis, rather than depending solely on periodic samples obtained from the traditional coal mine dust samplers, has been a goal in the mining industry for nearly two decades. Recently, an extensive series of laboratory and underground tests was conducted by NIOSH with the cooperation of MSHA and coal operators to test the performance of the MMCRDM In preliminary laboratory testing, the MMCRDM seemed to work well. However, in every underground test, when compared to reference samplers placed close to the inlet, the MMCRDM failed to meet the 25% accuracy criterion specified in the contract under which it was developed. Two reasons explain this failure: First, in most tests the bias (the relative discrepancy between the average MMCRDM concentration and the average reference sampler concentration) was too great. Second, the variability of the samplers used for reference comparison was too large. Finally, the underground testing of the MMCRDMs showed that they are quite unreliable at this stage of development. In the majority of mine tests, no more than 10 shifts of data were taken before the MMCRDM failed to function properly. Major breakdowns, requiring the return of the MMCRDM to the factory for repairs, occurred on average every 28 days. To be considered mine-worthy, MMCRDM reliability must be substantially improved. KEYWORDS Dust, coal dust, dust instrumentation, dust sampling, dust monitoring, black lung, pneumoconiosis

By Stephen C. Tadolini, Raymond A. Mazzoni

The International Ground Control Conference in Mining has always provided an open forum for the publication, presentation, discussion, and often heated debate on roof bolting systems mostly with attention to how, when, and why they work. During the last 24 Conferences at least 170 papers have been presented by International Experts on these “simple” devices that range in length from 30-inches to 20 ft and from 5/8 to 2 inches in diameter. Roof bolts are primarily mechanically anchored, glued, cemented, or driven. Bolts are placed vertically, angled, or tied together with special fixtures (trusses and slings). They have been termed active, passive, stick-slip, and several other descriptive acronyms or mining slang expressions. This retrospective paper will present the changes in bolt types and usage, point out some of the biggest myths and hail the most significant advances (according to the authors’ opinions of course).

By D. Harrington

"Coal—mine explosions are accidents that can and should be prevented. In former years hundreds of lives were lost each year in the United States as a result of such explosions, but after 1932 the numerous precautionary measures adopted had reduced their frequency and severity 75 percent or more until in 1940 several very disastrous explosions marred the good record. Unfortunately, both the number and severity of explosions seem to be tending to increase compared with the relatively good achievement from 1933 to 1940. The requisites for an explosion are ever present in all soft-coal and many hard-coal mines. A certain combination of circumstances, such as a flame or an arc in a cloud of dust or in a body of gas or both may start an explosion at any time. The fact that the frequency and severity of explosions were lowered for 6 or 7 years is no guarantee that such freedom from explosions will continue, as the bad record of 1940 has shown, and underground workers should feel honor bound to exercise the utmost care so that they will not help to bring about the circumstances that will cause an explosion.Although mine operators bear the main responsibility for preventing explosions, miners can do many things to help. As about 9 out of 10 explosions begin at a working face, it is largely within the power of workers to prevent them. All miners should do their part willingly and should not defend a fellow workman from punishment, even from discharge, for disobeying necessary rules, whose disregard may cause the death not only of the safety-rule breaker but also of many of his coworkers.When a miner is careless and is injured some other way than by an explosion he may be the only one to suffer, but if his carelessness causes an explosion he not only endangers his own life but also that of every other man in the mine and possibly the lives of persons outside the mine.Experiments have shown that ignition of as small a quantity as 150 cubic feet of an explosive mixture of methane and air under certain circumstances can start an explosion that will traverse an entire mine. Thus, ignition of an explosive mixture of gas 1 foot down from the roof and 13 feet back from the face of a 12-foot entry might cause a widespread explosion if the right quantity and kind of dust were present. Many persons have ignited much larger quantities of gas without being killed, but they survived only because dust, confinement, and other conditions were not exactly ""right."""

Nov 1, 1940

By R. L. Merek

There were 63 fatalities in the California petroleum industry in 1929, the largest number in any year since 1923 and an increase of 34.0 per cent over 1928, when 47 men lost their lives in the drilling, producing, manufacturing, and marketing divisions of the industry. It will be observed from the accompanying chart that after following a consistent decline for 4 years, the fatality curve turned upward in 1923 and advanced sharply in 1929. Although this increase in fatalities coincided with a period of intensive development it tends to indicate some laxness in the industry during a period of increased hazards. Intensive drilling campaigns are usually started hurriedly and conducted with a great demand for speed, and the result is that accident-prevention work is too often relegated to a position of minor importance.

Jan 1, 1930

By R. L. Marek

There were 63 fatalities in the California petroleum industry in 1929, the largest number in any year since 1923 and an increase of 34.0 per cent over 1928, when 47 men lost their lives in the drilling, producing, manufacturing, and marketing divisions of the industry. It will be observed from the accompanying chart that after following a consistent decline for 4 years, the fatality curve turned upward in 1923 and advanced sharply in 1929. Although this increase in fatalitics coincided with a period of intensive development it tends to indicate some laxness in the industry during a period of increased hazards. Intensive drilling campaigns are usually started hurriedly and conducted with a great demand for speed, and the result is that accident-prevention work is too often relegated to a position of minor importance. [ ]

Jan 1, 1930

By L. McWilliams, L. D. Patts, J. D. Noll, S. E. Mischler

Elemental carbon (EC) is currently used as a surrogate for diesel particulate matter (DPM) in underground mines since it can be accurately measured at low concentrations and diesels are the only source of submicrometer EC in underground mines. A disadvantage of using EC as a surrogate for DPM is that the fraction of EC in DPM is a function of various engine parameters and fuel formulations, etc. In order to evaluate how EC predicts DPM in the underground mining atmosphere, measurements of total carbon (TC; representing over 80% of the DPM) and EC were taken away from potential interferences in four underground metal/non-metal mines during actual production. In a controlled atmosphere, DPM mass, TC, and EC measurements were also collected while several different types of vehicles simulated production with and without different types of control technologies. When diesel particulate filters (DPFs) were not used, both studies showed that EC could be used to predict DPM mass or TC. The variability of the data started to increase at TC concentrations below 230, µg/m3 and was high (>+20%) at TC concentrations below 160 µg/m3, probably due to the problem with sampling organic carbon (OC) at these concentrations. It was also discovered that when certain DPFs were used, the relationship between DPM and EC changed at lower DPM concentrations.

By Paul W. Johnson

A computer program for calculating capital and operating costs from material and energy requirements and equipment costs for use in preparing cost estimates for metallurgical process evaluations has been written by the Bureau of Mines' College Park process evaluation group. The program permits rapid recalculation of processing costs when changes of data or equipment are desired, and produces tables of capital and operating costs suitable for publication. Equipment cost summary tables for each process section end supplemental information for input-data checking is included in the computer printout. The program is written in Fortran IV except for several subroutines which are written in machine assembly language for the IBM 7094.3 With a few modifications, the program can be used on other computers.

Jan 1, 1969

By Larry A. Haas

The chemistry of current or potential SO2 removal processes can be placed into four categories: (1) reduction, (2) Liquefaction, (3) direct dissolution, and (4) oxidation. Methods that involve reducing SO2 to elemental sulfur appear promising since this product can be easily handled, shipped, and stock- piled. Unfortunately, SO2 cannot always be reduced directly when other oxidizing agents are present. Thermodynamic data indicate that some oxidizing reagents will also consume reductant at the reduction temperature. A two- stage process can be applied to waste gases that contain excessive quantities of oxygen, nitrogen oxides, and water vapor. The best sorbent for the first stage appears to be a nonalkali or nonalkaline earth medium since this medium more readily releases the SO2 for reduction in the second stage.

Jan 1, 1973

By H. F. Yancey

The investigations described in this bulletin are confined to a study of the washing characteristics of bituminous coals. The major part of the work was conducted by the Bureau of Mines in cooperation with the Engineering Experiment Station of the University of Illinois and the State of Illinois Geological Survey Division between 1918 and 1924, in accordance with the provisions of an agreement between these agencies. The washing characteristics of coals from many of the important coal-producing fields of the Eastern and Central States were examined. The coals of the Pacific Northwest States and Alaska have been studied separately by McMillan and Bird of the Northwest Experiment Station of the Bureau of Mines at Seattle in cooperation with the College of Mines of the University of Washington.2 OBJECT OF INVESTIGATION The object of the investigation of coal preparation by the Bureau of Mines has been to promote the production of better prepared coal and to facilitate the correct selection and design of coal-preparation plants by obtaining as complete information as possible regarding the washability of the various types of American coals and the treatment best suited to each. In addition, some attention has been given to the development of new methods of washing coal. The work naturally divides itself into three rather distinct steps: (1) Development of a systematic method of examining and testing a coal; (2) classification of the American coals on a basis of the occurrence of the impurities associated with the coal in the beds; (3) examination of one or more representative coals of each type.

Jan 1, 1929

This summary of State laws on explosives was compiled primarily to ascertain what subjects relating to their control have been acted upon by each State legislature and, in general, how they have been treated. It does not include any legislation passed after 1942, or any proclamations, regulations, or administrative orders. It does not purport or attempt to be authoritative. If any problem arises involving interpretation of the statutes of any particular State, the original source must be consulted for the exact words used by the legislature. This summary, however, will be useful in determining whether relevant statutes exist and in locating them quickly, with a minimum of effort. It will be of value also in comparing statutes in one State with similar statutes in other States to determine what construction has been placed upon them by the courts of those jurisdictions or to contrast the varying provisions of many States upon a single subject. To make these comparisons easier, the statutory provisions for each State have been grouped under several major topics in outline form. Although

Jan 1, 1943

By J. E. Chilton

The National Institute for Occupational Safety and Health (NIOSH) has conducted research to determine the influence of mining machine-mounted scrubbers on airflows and methane concentrations at the face when blowing ventilation systems are used. Tests were conducted in a full-scale ventilation gallery with a model mining machine that simulated airflow created by a dust scrubber. During the tests, ultrasonic anemometers were used to measure airflow speed and direction at several locations near the face. For the same test conditions, methane was released from the face and gas concentrations were measured at 21 locations above the machine using fixed point methanometers. Changes in airflow speed and direction are correlated with scrubber airflow and the measured methane distribution above the mining machine. The research results showed that operation of machine-mounted scrubbers improved face ventilation when blowing ventilation is used by increasing both the intake flow and the quantity of air reaching the face.

By C. E. Julihn, Lowell B. Moon

"INTRODUCTION To increase the supply of ore needed to produce steel the Bureau of Mines has explored 187 mineral deposits containing chromium, iron, manganese, cobalt, nickel, fluorspar, tungsten, vanadium, or coal during the fiscal years. 1940-44, the deposits thus explored were selected from several thousand that were first examined to appraise their possibilities. The objective of the exploration was to determine the tonnage and grade of ores upon which mining, operations might be based, and the metallurgical processing that was most suitable for their utilization.Most of these deposits were sub-marginal by pre-war standards; hence there had been no incentive for their exploration, yet many such deposits were known to exist that probably contained ore sufficient in grade and amount to be utilized as war reserves.Some of the Bureau's exploration projects have disclosed substantial or even very large amounts of ore, much of which is fairly high in grade. In a few of them bodies of high-grade ore have been found, though in others the tonnage has proved to be too small or too low-grade for utilization."

Mar 1, 1945

By Erik Sherer

Indonesia is poised to become a major player in the Pacific Rim thermal coal markets. Although the colonial Dutch developed numerous coal mines in the late 1800's for steamship bunkers and domestic fuel, Indonesia's coal industry has only recently begun to actively participate in the growing global marketplace. This export coal is primarily the result of the commercial development of coal mines in eastern Kalimantan by foreign contractors. From virtually no coal exports in the late 1980?s, Indonesia's coal industry has increased its exports to approximately 15 million metric tons (Mmt) in 1992. In 1992, Indonesia was the world?s sixth largest exporter of steam coal, By the year 2000, Indonesia projects that it will supply approximately 25 percent of the seaborne thermal coal requirements of the Pacific Rim countries. Although limited quantities of this coal may enter the European and U.S. markets, high qualities, low production casts, and favorable transportation rates will make Indonesian coals very competitive in the rapidly growing Pacific Rim markets. This study examines the Indonesian coal mining industry and compares it to the U.S. coal mining industry. This report is the sixth in a series of coal exporting country studies requested by the House Appropriations Committee. Previous studies examined the Colombian, Canadian, Australian, South African, Polish, and Venezuelan coal industries.

Jan 1, 1994

By Robert F. Randolph, Christa L. Themann, Efrem R. Reeves, Thais C. Morata, Babette L. Verbsky, David C. Byrne

Objective: Workers with hearing loss face special problems, especially when working in noise. How­ever, conventional hearing conservation practices do not distinguish between workers with normal hearing versus impaired hearing. This study col­lected information from workers with self-reported noise exposure and hearing loss, supervisors of such workers, and hearing conservation program managers through focus groups and in-depth inter­views to evaluate their perspectives on the impact of hearing loss on safety and job performance, the use of hearing protection, and information needed to appropriately manage hearing-impaired workers who work in noisy environments. Results: Concerns about working in noise with a hearing loss could be grouped into the following 10 categories: impact on job performance, impact on job safety, impaired ability to hear warning signals, impaired ability to monitor equipment, interfer­ence with communication, stress and/or fatigue, impaired communication caused by hearing protec­tor use, reduced ability to monitor the environment as the result of hearing protector use, concerns about future quality of life, and concerns about future employability. Mostly, there was an agree­ment between the perceptions of workers, supervi­sors, and hearing conservation program managers regarding difficulties associated with hearing loss and consequent needs. These findings suggest that noise-exposed workers with hearing loss face many of the same problems reported in the literature by noise-exposed workers with normal hearing, with additional concerns primarily about job safety as the result of a reduced ability to hear environmental sounds, warning signals, and so forth. Conclusions: The study outlines potential chal­lenges regarding job safety and hearing conserva­tion practices for noise-exposed, hearing-impaired workers. Awareness of these issues is a necessary first step toward providing appropriate protective measures for noise-exposed, hearing-impaired workers. Of the 19 million adults in the United States with some degree of hearing trouble, nearly half are currently employed in the workforce (NCHS, 1994). More than 30 million US workers are exposed to hazardous noise levels, and noise-induced hearing loss is the most common occupational disease in the United States (NIOSH, 1996). Many workers incur their hearing losses during the first 5 to 10 yrs of employment (Rosler, 1994; Ward et al., 2000) and subsequently work the rest of their careers in an environment where noise and hearing loss interact to impair their ability to hear communication and other important signals. Workers with hearing loss who are exposed to hazardous noise levels present a dilemma to hearing loss preventionists. On the one hand, it is of great importance to ensure that their residual hearing is protected from the damaging effects of the noise to which they are exposed. On the other hand, how­ever, traditional hearing protectors serve to further “deafen” such workers, making communication more difficult and impairing the detection of environmen­tal sounds and warning signals. These workers have special needs that must be addressed. However, conventional hearing conservation practices do not distinguish between workers with normal versus impaired hearing; and, to date, no governmental or professional organization has developed specific guidelines or policies concerning the accommodation of noise-exposed, hearing-impaired workers. Some research regarding noise-exposed, hearing-impaired workers has been completed. These studies have primarily focused on three areas: (a) speech intelligibility in noise versus quiet, with and without various types of hearing protection devices (Abel et al., 1982; Abel et al., 1993; Abel & Spencer, 1997; Rink, 1979; Suter, 1989); (b) signal detection and localization under similar conditions (Abel et al., 1993; Abel et al., 1985; Abel & Hay, 1996); and (c) the use of hearing aids as hearing protectors (Berger, 1986; Dolan & Maurer, 1996; Hétu et al., 1992; Hétu et al., 1993). Research in these three areas has provided an initial framework for development of a management para­digm for these workers. However, each of these studies addressed a very specific research question, examining

By D. J. Bauer

Oxidation of mixed lanthanide solutions with ozone at pH 4.5 and at ambient temperature resulted in precipitation of 98 percent of the original cerium present. Corresponding cerium purity was increased from 50 to 98 percent. A second ozone oxidation-precipitation step produced cerium of 99.9 percent purity in high yield from the 98-percent-pure material. Alternately, ozonation at pH 6.5 and 85° C differentially precipitated cerium and rare-earth elements heavier than cerium and left 89 percent of the original lanthanum in solution at a purity of 95 percent. Subsequent recovery of cerium from the heavier rare-earth elements in the precipitate was accomplished by dissolving the precipitate in dilute mineral acid and reoxidizing the cerium with ozone at pH 4.5 and at ambient temperature. The filtrate contained an enriched praseodymium-neodymium-samarium-europium mixture that is amenable to separation by ion exchange or solvent extraction.

Jan 1, 1968

By John J. Sammarco

Miners depend most heavily on visual cues to recognize underground mining hazards; consequently, illumination plays a critical role in miners? safety. Some hazards are located in the miners? peripheral field-of-view (10 degrees to about 60 degrees off-axis) or on-axis (0 degrees). The objective of this research was to determine if there were visual performance improvements when using solid-state cap lamps with light-emitting diodes (LEDs) as compared to incandescent light bulbs commonly used in miner cap lamps. Recent research has indicated that an increased short-wavelength content of the spectral power distribution of LEDs relative to incandescent lamps improves peripheral visual performance for low-light (mesopic) conditions. The visual performances of nine subjects were quantified by measuring the subjects? speed and accuracy in detecting floor objects located on axis and at ±20 degrees off axis. The objects were located near field (1.83 meters) and far field (3.66 meters). Upon presentation of the objects, subjects would count and point to each object using a red-laser pointer. The object detection response time and number of missed objects were recorded. The results of the visual performance comparison for an LED, a prototype LED, and an incandescent cap lamp are presented. There we no missed objects when subjects used the LED-based cap lamps but, there were three missed object occurrences when subjects used the incandescent cap lamp. The mean detection time when using the incandescent cap lamp was 55.3% greater than the prototype LED cap lamp and 43.5% greater than the LED cap lamp. It can be inferred from this data that the spectral distribution of LED-based cap lamps could enable significant visual performance improvements as compared to incandescent cap lamps1.

Jan 1, 2007