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By M. Townsend, E. L. Petsonk, H. Abrons, E. Daniloff, K. Kinsley

Workers exposed to certain inhaled dusts may show increased levels of nonspecific airways responsiveness (AR). In some studies, cigarette smokers have also been reported to have increased levels of AR. As part of an ongoing study, we compared the results of preshift methacholine inhalation challenge, spirometry, and smoking and occupational histories, in 191 under-ground bituminous coal miners (M) and 215 non-mining control workers· (C) . All M and c were selected to have normal baseline% predicted FEVI (PPFEV). Mining tenure was recorded as years worked underground (YRUG) and at the coal face (YRFC). AR was assessed as the% decrease in FEVI from baseline divided by the dose of methacholine delivered. M reported similar years smoked (YRSM) but fewer pack-years* (PY) than c~ Overall, both increasing YRSM and PY were associated with more AR*. Smoking C* but not M showed increased AR with increasing PY. In smoking and nonsmoking M, baseline AR and PPFEV showed no association with YRUG. The level of AR was inversely related to YRFC*, possibly representing selection away from dustier jobs. AR was inversely correlated with PPFEV*. In this study, AR and baseline PPFEV were not significantly associated with mining tenure, but cigarette smoking was related to both baseline lung function and level of AR. * p < 0.05 (Supported in part by Grant Gll35142, us Bureau of Mines, Generic Mineral Technology Center for Respirable Dust.)

Jan 1, 1989

By Donald P. Tuchman

The U.S. Bureau of Mimes is investigating Fourier transform infrared (FTIR) spectroscopy for on- filter quartz analysis of respirable dust. A custom accessory is described for full-face examination of filters utilizing a large-diameter infrared (IR) beam. The accessory positions samples to match diameters with that of the diverging analytical beam. Sample absorbance is then measured. With nonuniform deposition of dust on collection filters being a major issue for such analyses, this approach is the most direct way to accomplish sample area averaging. The approach is unconventional since it utilizes large-beam geometries instead of the usually desired minimized beam dimensions. The issues and problems involved in the analysis of quartz on a filter matrix are discussed. Absorption bands chosen, light-scattering effects, curved baselines, random noise, interference fringes, and possible solutions to technical difficulties are the topics covered. The more significant findings include a 20-pg detection limit for quartz when the custom accessory is used and minimal occurrence of light-scattering effects at low wavenumbers. The custom accessory performance was satisfactory and merits further work. With continued research, an on-filter method for quartz analysis of respirable dusts seems achievable.

Jan 1, 1992

By Launa Mallett

This paper introduces a method for teaching workers to communicate necessary information when giving or receiving emergency warning messages. Research has shown that when an emergency occurs, people may not get the information they need to take appropriate action. Interviews conducted with 48 underground coal miners who had escaped mine fires revealed that the warning information provided was inadequate. In some cases, sufficient information was not provided to the endangered miners. At other times, miners failed to ask for information they needed to plan and execute effective escapes. Researchers from the NIOSH Pittsburgh Research Laboratory have been studying the content of emergency warning messages and have developed an emergency communication protocol. A training intervention that presents the protocol and related mental cues is being evaluated for effectiveness in improving the content of emergency messages. In this paper the protocol is presented and the training package described. The evaluation procedures and a summary of the analyses conducted to-date are also provided. The training package was developed for use with underground coal miners, but could easily be modified for emergency communications training in other settings.

Jan 1, 2000

By S. D. Hudock, C. M. Keran

A review of all upper extremity cumulative trauma disorder (UECTD) injuries was conducted by the U.S. Bureau of Mines for 1985 through 1989. This review was performed by analyzing each injury, as reported by law and maintained on the U.S. Mine Safety and Health Administration&apos;s accident data base. This analysis found that incidence rates in mining were lower than in private sector industry, although the number of reported UECTD injuries increased sevenfold and their percentage of all mining injuries increased fivefold from 1985 through 1989. Metal-nonmetal mines accounted for 80 pct of UECTD injuries, while coal mines accounted for 20 pct. Nearly 63 pct of UECTD injuries were accounted for by only four occupations-mechanics, laborers, boney (crusher) operators, and miners not elsewhere classified (NEC)-with an incidence rate well above the private sector industry rate.

Jan 1, 1992

By Launa Mallett, Charles Vaught, Jr. Brnich

This paper introduces a technique for incorporating employee participation into the prevention component of a contingency plan. Companies sometimes focus so much energy on response that they forget to put resources into the basics of emergency prevention. The training program discussed here was designed to make employees part of the prevention system. Examples of training materials from the program are provided, a sample method for introducing risk assessment to employees is shown, and a strategy to address limited training time using short videos is explained. Methods for tailoring the training to any worksite and for specific risks are also included. The program is being designed and tested by the Pittsburgh Research Laboratory/NIOSH and employees of an underground coal mine. Examples are taken from the implementation of the program at the mine during the summer and fall of 1998. Results of the program evaluation and lessons learned during the implementation are discussed.

By Allen Q. Howard

An approximate solution to the electromagnetic boundary value problem consisting of a horizontal cylindrical conductor buried in a lossy half-space and excited by an arbitrarily oriented magnetic dipole is found using an iterative perturbation technique in a double Fourier transform space. This model is used to gain insight into the anomalous fields due to strong scatterers such as pipes or tracks which would be in close proximity to an EM mine rescue operation. The novel, three-dimensional aspect of the problem (i.e., the source) imposes the complexity that the current in the cylinder is not uniform. The field expressions are ideally suited to evaluation using FFT algorithm.

Jan 1, 1973

By Giorgio Franceschetti

Explicit expressions are presented for the input admittance and effective height of several buried metal antennas, namely: (i) prolate spheroidal; (ii) spherical; (iii) oblate spheroidal; (iv) parallel plate; (v) parallel plate with protruding dielectric in the same plane of the plates; (vi) parallel plate with protruding dielectric in a plane normal to that of the plates (H-shaped antenna). Explicit expressions are presented for the input admittance and effective height of several buried metal antennas, namely: (i) prolate spheroidal; (ii) spherical; (iii) oblate spheroidal; (iv) parallel plate; (v) parallel plate with protruding dielectric in the same plane of the plates; (vi) parallel plate with protruding dielectric in a plane normal to that of the plates (H-shaped antenna). It is concluded that in all practical situations of "small" antennas approximation 1 is almost always appropriate. Computations were carried out for bare antennas, the extension to insulated ones being, however, straightforward. Although a rigorous theory of the antenna performance in a realistic semi-infinite conductive medium has not been developed, the results quoted should also be applicable when antennas are a few skin depths below the earth&apos;s surface. In particular, for the evaluation of radio-links under up-over -and-down operating conditions, the antennas can be replaced by dipoles of length equal to the effective height. Since the antenna&apos;s parameters are given in analytical form, it is also possible, by using Laplace transform techniques, to compute the transient response of the antenna. The transient is described by pole (short-time behavior) and branch-cut contributions (large time behavior). For these last terms, an asymptotic evaluation is possible, so obtaining closed form expressions for the response at large observation times, which is closely related to the dispersion characteristic of the environment.

Jan 1, 1973

Tables

Jan 1, 1992

By W. C. Smith

The U.S. Bureau of Mines examined previous research on rib stability in an effort to develop a practical approach to understanding, characterizing, and controlling weak rib conditions in underground coal mines. Because success in stabilizing ribs depends on a basic knowledge of how weak ribs behave, the report reviews the mechanics of rib failure and the relationship of coal mine geology and pillar constraint to rib instability. Strategies for choosing an effective method of rib support are considered, and various rib support methods are discussed. Finally, the report documents techniques for monitoring ribs and use of models to assess rib stability; such monitoring and modeling can also help determine the most effective method for roof support.

Jan 1, 1992

By Dorsey A. Lyon, Robert M. Keeney

This bulletin is one of a series dealing with the application of the electric furnace to the smelting of ores and the manufacture of alloys, and is published by the Bureau of Mines in the endeavor to increase efficiency in metallurgical processes. The bulletin presents, first, a critical discussion of the possibility of smelting copper ores in the electric furnace; second, the results of the experimental work of other investigators on the electric smelting of copper; third, the results of experiments by the authors on the electric smelting of native copper concentrates and sulphide copper ores; and, fourth, a comparison of the electric furnace with the blast furnace and reverberatory furnace for copper smelting. Before considering the electric smelting of copper ores the reader should understand that the electric furnace was not developed as a competitor of the combustion furnace, but for the purpose of doing high-temperature work that can not be done in the combustion furnace, and for the treatment of ores from deposits that are in regions where fuel is scarce and costly but hydroelectric power is comparatively cheap, as in Chile, and in certain parts of Canada, the United States, and Mexico. Furthermore, it is not the object of this report to try to prove that the electric furnace should replace the reverberatory or the blast furnace, as used at present in smelting copper ores, but to show that the electric furnace may be used with advantage in localities where conditions are not favorable to the use of the reverberatory or the blast furnace. For example, otherwise valuable ore deposits may be situated in a district so remote from, or inaccessible by, railway that the cost of get- ting coke for smelting, or of transporting the ore to a smelter, is pro- hibitive. If there is sufficient water power at hand, from which electric power can be developed at a reasonable cost, and this electric power is used for smelting the ore in an electric furnace, with subse- quent bessemerizing, if necessary, the concentrated product may be

Jan 1, 1915

By Fred N. Kissell

The U.S. Bureau of Mines was established in1910 to reduce .the high accident rate in the nation&apos;s coalmines. For 85 years, it conducted a wide variety of tasks related to mining before it was abolished in 1995. The BOM had many technology transfer successes in its lifetime, including more than a dozen "R&D100" awards. This essay identifies and discusses five "transfer factors" that can explain the success (or failure) of many Bureau of Mines projects. These five factors are termed "pressure, pitfalls, path, price, and profit."

By W. E. Caspar, W. L. Eaton, W. M. Rohmiser, James Westfield, E. J. Podobrski, L. H. Johnson, S. H. Ash

A flood in mine workings is a crisis even if no lives are lost, and when the crisis is past and the excitement wanes there is usually a rapid return to unwarranted complacency in those regions where floods occur, even though the danger of imminent recurrence is known. Experience in flood control, regardless of its nature, has taught that in a flood the work does not cease when the emergency passes; rather, it increases as the water recedes. To do nothing, when it is known that a hazard exists, is inexcusable for those that should do something. To prevent floods in mines, data should be collected and something constructive done with those data, not alone for present conditions but for the future.

Aug 1, 1947

By Frank J.

The increased demand for aluminum for military purposes during World War II necessitated the development of domestic deposits of alumina-bearing ores. Kaolin, siliceous bauxites, anorthosite, and diaspore-containing clays have been investigated and studied in the laboratory and pilot plant. The Bureau of Mines is preparing a series of reports covering investigations of these ores. The tests contained in this report are restricted to sintering and leaching tests on kaolin from South Carolina, where extensive deposits were proved to exist. The leach liquors were found to have substantially the same composition as those produced from the diaspore-containing clays, and therefore it would be expected that no difficulty would be experienced in producing calcined alumina of relatively coarse particle size and with other properties conforming to the specifications for metallurgical-grade alumina.

May 1, 1947

By David Ingram

The results from the sound level measurements, the dosimeter recordings and the time-activity studies on four different air-rotary rigs indicate a wide variation of operator noise exposure during hole development. These variations appear to be dependent on the cab design and the operator?s drilling behavior. Studies have documented that exposure to high sound levels for long periods of time can cause hearing loss. The results of this study help identify the loudest parts of the drilling cycle. Sound level measurements on the four rigs show that all the rigs generate sound levels that are 90 A-weighted decibels (dB(A)) and above within 6 feet around the rigs during drilling. It is easy to conclude that some type of noise protection, such as a cab, is needed to protect the operator from overexposure to noise for an eight-hour shift of uninterrupted drilling. However, even when rigs are outfitted with cabs, operators observed in this study are being exposed to sound levels above 90 dB(A) during some activities required to complete a drilling cycle. An evaluation and comparison of the four dosimeter recordings and time-activity studies during one drilling cycle may explain why variations in operator exposure occur. Table 1 summarizes the time-weighted average (TWA) and accumulated dose percentages for each of the four operators during the time needed to complete one typical hole cycle.

Jan 1, 2008

By A. D. Garman

This paper presents one of a series of digests of foreign mining legislation and court decisions which is being prepared in advance of a general report relative to the right of American citizens to explore for minerals and to own and operate mines in various foreign countries . This interpretation of the laws of Haiti has been prepared from the best available information in Washington, but is released subject to correction and amplification , if necessary , by the proper American diplomatic and consular officers to whom it is being referred through the courtesy of the Department of State .

Sep 1, 1930

By E. A. Barrett, L. L. Rethi, B. Fotta

Employment and accident trends of independent contractors working at coal and noncoal mines in the United States are reported. Data include employee hours and accidents, both fatal and nonfatal, from 1985 through 1994. Also noted are increases or decreases in certain accident classifications and accident rates, particularly those which have shown significant change during the ten-year period.

By Robert H. Peters, George R. Bockosh, Barbara Fotta

This paper was commissioned by the Japan Technical Cooperation Center for Coal Resources Development. It is to be published in a proceedings following a series of presentations to Japanese coal officials in February 1997. The paper focuses primarily on summarizing the past 20 years of U.S. research on promising techniques for ensuring that underground coal miners work safely. These techniques can be grouped into three major categories: management, workplace design, and training. Each technique is described, and the results of efforts to apply the technique at underground coal mines are summarized. Recent statistics on accidents and productivity in U.S. underground coal mining operations are presented before the overview of research findings is given. Because Japanese coal mines are using the longwall method of coal extraction, separate statistics are given for U.S. longwall versus room-and-pillar coal mining operations.

By Peter. PH. D. Cain

Smoky River Coal Ltd. mines low-volatile metallurgical coal by surface and underground methods in the foothills of the Rocky Mountains of Alberta, Canada. Current underground operations are confined to the 5B-4 Mine. Development of 5B-4 began in January 1998; production from depillaring sections commenced in July 1998. This paper describes the history of underground mining on the Smoky River property in terms of extraction methods and pillar design. The development of the present pillar design guidelines is discussed in this context. Recent work to prepare a number of case histories for back-analysis using the Analysis of Retreat Mining Pillar Stability (ARMPS) method is described, along with the modifications developed for calculating the ARMPS stability factor for retreat extraction of thick seams. The design criteria are described, as well as the geotechnical program implemented in order to verify its applicability.

Jan 5, 1999

By R. V. Ramani, A. S. C. Owili-eger

The Methane Generator program is a part of the Internal Environ¬mental Sub-system of the Master Design Simulator (MDS). All the sub¬systems of the MDS are controlled and activated by the main program as required. The data requirements for the Methane Generator are supplied by the Geology and Reserves sub-system through common storage. Figure 6 shows the information flow between the Methane Generator and other systems of the MDS. It should be noted that the Methane Generator can also function independently as was described under model application. AREAS OF MISSING INFORMATION In any numerical analysis, the accuracy of the solution depends entirely upon the data available. In gas flow problems, parameters that constitute basic model input data are rock porosity, medium permeability, reservoir pressure and initial reservoir pressure dis¬tribution. Unfortunately, however, most of these characteristics are not available for a lot of coal seams. The need for actual field data cannot, therefore, be adequately emphasized here.

Jan 1, 1974

By L. C. IlsLey, M. W. Means

The United States Bureau of Mines under provisions of Schedule 20 issues approvals covering complete operating units such as loading machines, room hoists, and storage-battery locomotives. Certain manufacturers design and build entire machines. Other manufacturers purchase a part or all of the electrical accessories from manufacturers of electrical equip- ment and assemble them, thereby making up a permissible unit. Before the assembler purchases electrical accessories for use in such contempla.ed units he may require certain information from the accessory manufacturer as to whether these par- ticular accessories are suitable for assembly in his proposed permissible outfit. In order to aid accessory manufacturers in marketing their product, a provision was incorporated in Schedule 20 whereby tests might be made on individual accessories and reports rendered as to the suitability of a given accessory for use in permissible assemblies. The section of Schedule 20 which permits this special work reads as follows:

Jan 1, 1932