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PURPOSE: Evaluate practical technological advances in hearing protective devices for use in different mining environments RESEARCH SUMMARY: Previous NIOSH research shows that miners develop hearing loss much more quickly than nonoccupationally noise-exposed individuals and that miners experience a greater severity of hearing loss than would be expected for nonoccupational noise-exposed persons of the same age and sex. As described in the National Occupation-al Research Agenda, problems created by occupational hearing loss include(1) reduced quality of life due to social isolation and unrelenting tinnitus,(2) impaired communication with family members, the public, and coworkers, (3) diminished ability to monitor the work environment (i.e., warning signals, equipment sounds, etc.), (4) lost productivity and increased accidents resulting from impaired communication and isolation, and (5) expenses for workers? compensation and hearing aids.

Jan 1, 2001

By Joan Weinberg

The real gross national product (GNP) expanded by 2.3% during the second quarter, down from the anomalous 4.4% growth rate in the previous 3 months. If the expansion continues through October, it will have lasted 5 yr and become the second longest in 40 yr.2 As in the first quarter, improvement in U.S. exports played a role in the continuing--albeit slow--growth. More than 2 yr of declines in the dollar relative to currencies of other industrial countries have contributed to a slight reduction in the trade deficit in real (volume) terms, as real net exports of goods and services rose $1.9 billion (table 1). Exports grew a strong 12.1% while imports, which had fallen the previous two quarters, rose 7.4%. Manufactured goods and petroleum products accounted for most of the second quarter import increase. The American Petroleum Institute estimates that the volume of crude oil and refined products imports in the first half of 1987 surpassed those in the same period last year by 7.5%, reflecting falling domestic production and higher than expected demand. Expenditure on durable goods--those that last at least 3 yr-by both consumers and producers also contributed to the second quarter expansion. Personal consumption of durable goods rose 9.0%, after having fallen the two previous quarters. Motor vehicle purchases accounted for most of the second quarter increase and the first quarter decrease. Sales of automobiles surged in the last quarter of 1986, as consumers rushed to capture the sales tax deduction that was eliminated on January 1. Sales fell in the first quarter of 1987, but have now moved closer to the trend line exhibited in the first three quarters of 1986. Automobiles accounted for half the 0.8% July gain in retail sales, and two-thirds of the 1.4% June gain. Producers durable equipment purchases also rose this quarter, accounting for the increase in nonresidential fixed investment.

Jan 1, 1987

By Catharine T. Fogg

The U.S. Bureau of Mines investigated the availability of platinum, palladium, and rhodium from 16 deposits in four market economy countries (MEC's). Major recoverable products include 164 Moz of platinum, 80 Moz of palladium, 13 Moz of rhodium, 24 Moz of ruthenium, 4 Moz of Iridium, 2 Moz of Osmium, and 10 Moz of gold. The 12 deposits in the Republic of South Africa are estimated to account for 96.7 pct of total recoverable platinum. The base-case scenario estimates the long-term cost of production including recovery of capital, but provides no return on the investment or O-pct discounted cash-flow rate of return (DCFROR). The total production costs in January 1990 U.S. dollars ranged from $325/oz to $1,288/oz of platinum compared to an average January 1990 price of $492/oz. Approximately 83 pct of total recoverable platinum was economic at a cost level of $4S0/oz or less. At the IS-pct DCFROR, only 26 pct of total recoverable platinum was economic. For platinum-group metals (PGM), attention has been focused on the ratios of the three primary metals: platinum, palladium, and rhodium. Sensitivity analyses were performed to determine the impact long-term rhodium price increases could have on the total cost of production for platinum and palladium.

Jan 1, 1993

By H. Tomlinson

Fatalities from falls of roof and coal are responsible for the death Of more than 1,000 miners annually in the bituminous coal mines of the United States, or practically one-half of the total fatalities In and about these mines. The men are killed by falls singly or in small groups and little or no publicity is given these accidents as they lack the spectacular features of gas and dust explosions. As a result, the public and even the miners have the impression that accidents from falls of roof and coal are just one of the unavoidable hazards of the coal-mining industry. This belief is not true. Accidents caused by falls can be avoided largely by the application of sound engineering principles, by education, and by proper leadership in the industry, just as gas and dust explosions and accidents caused by explosives have been reduced in recent years. The necessity for studying falls of roof and coal becomes apparent by referring to the following data from a table by Adams and Chenoweth:3

Jan 1, 1933

By H. Tomlinson

Fatalities from falls of roof and coal are responsible for the death of more than 1,000 miners annually in the bituminous coal mines of the United States, or practically one-half of the total fatalities in and about these mines. The men are killed by falls singly or in small groups and little or no publicity is given these accidents as they lack the spectacular features of gas and dust explosions. As a result, the public and even the miners have the impression that accidents from falls of roof and coal are just one of the unavoidable hazards of the coal-mining industry. This belief is not true. Accidents caused by falls can be avoided largely by the application of sound engineering principles, by education, and by proper leadership in the industry, just as gas and dust explosions and accidents caused by explosives have been reduced in recent years.

Jan 1, 1933

By Walter T. Lewieki

"INTRODUCTION Numerous deposits of iron ore are found in Cherokee, Bartow, Floyd, and Polk Counties in northwest Georgia. The deposits are generally small and irregular in shape. The ore is usually referred to as ""brown ore"" and is predominately limonite. The crude or ""bank ore"" has to be washed and concentrated before being shipped.The proximity of the deposits to the Birmingham furnaces and a favorable freight differential permit the operation of many deposits that otherwise would be uneconomical. The district produced 413,468 long tons of brown-ore concentrates, averaging 45.53 percent iron in 1943.The necessity of developing additional iron-ore reserves for the war energeucy to supplement the production of the Birmingham district, prompted the Bureau of Mines to initiate exploration of the more promising northwest Georgia deposits. Thirteen properties in the four counties were explored during the program (fig. 1).HISTORY AND PRODUCTIONSeveral furnaces were operated in the district until the early 1900's, ranging from charcoal furnaces to more modern plants with capacities up to 50 tons of pig iron. No furnaces have operated for about 40 years, the product being shipped to Alabama and Tennessee.Bartow County iron mining is declining, although formerly it was the principal producer of the district. Most of the known merchantable ore deposits have been exhausted. For the past 3 years the Mitchell-Hodge mine has annually produced about 225,000 long tons of concentrates containing 46 to 43 percent iron and at present is the only large producer in Bartow County."

Jan 1, 1946

By F. S. Boericke

"INTRODUCTION The mineral found in natural-chromite deposits is never pure Fe0.Cr203, but rather one in which the Fe0 and Cr203 are in part replaced by Mg0 and A1203, respectively. The purest gravity concentrates from many domestic de¬posits consist of a mineral referred to as ""picotite,"" in which this isomorphous replacement is such that the ratio of chromium to iron is low. The Bureau of Nines has investigated methods of chemically beneficiating ores that contain too much iron to be classed as ""high-grade"" chromite 3/ Early investigations 4/ demonstrated that high-iron chromite or picotite ores can be roasted with carbon to obtain selective reduction of the contained iron, and that most of this reduced iron can be removed by acid-leaching the roast products to produce residues of higher chromium-to-iron ratios. tests 5/ indicated that commercially acceptable reaction rates cannot be obtained at roasting temperatures below 1,3000 C., using solid carbon as reducing agent. By this high-temperature reduction and subse¬quent acid-leaching, however, all ores investigated, regardless of the original composition, readily yielded residues considerably better than the minimum specifications for high-grade chromite.In an effort to obtain satisfactory reduction of chromite at lower temperatures, liquid and gaseous seducing agents were tested with varying success. Of the several reducing agents used, methane appeared to be the most promising and was shown to be highly effective at temperatures between 1,000º and 1,100º C., roughly 300º below the roasting temperatures necessary in solid carbon reduction. Further experiments indicated that mixtures of methate with some diluent (hydrogen or other nonoxidizing gas) gave better reduction than did methane alone."

Feb 1, 1946

By Jennifer Riefenberg

A family of personal computer programs that calculate the Coal Mine Roof Rating (CMRR) has been developed by the U.S. Bureau of Mines. The CMRR rock mass classification system provides a link between the qualitative geologists' description of coal mine roof and the quantitive mine engineers' needs for mine design roof support selection, and hazard detection. The program CMRR is a user-friendly, interactive program into which raw field data are input. A CMRR is calculated and output along with two graphic displays. The first graphic display is a plan view trap with the CMRR's displayed on a color-coded scale. The second display shows a stratigraphic section of the bolted roof interval and its resultant CMRR. In addition, a Lotus 1-2-3 worksheet, computer file BOM-CMRR.WK3, has been developed for easy storage of field data. The worksheet includes four macros that automatically calculate CMRR's, store field test data in a database format, and print a two-page report of the field data and CMRR parameters. Production of summary port; for analysis of site-specific information are readily generated using Lotus 1-2-3 software. These programs help to facilitate the engineer in utilizing the CMRR in ground control studies.

Jan 1, 1994

By D. D. Hamilton

The ISMS program provided for the development and demonstration of equipment modifications for improved safety in both conventional and continuous coal mining systems. This report documents the success of the program in identifying accident hazards in underground coal mines with 4-to 8-foot seam heights, in designing modifications to reduce the hazards, and in demonstrating improved safety through extended underground use of the ISMS equipment.

Jan 1, 1977

By David C. Byrne

PURPOSE: Evaluate practical technological advances in hearing protective devices for use in different mining environments. RESEARCH SUMMARY: Previous NIOSH research shows that miners develop hearing loss much more quickly than nonoccupationally noise-exposed individuals and that miners experience a greater severity of hearing loss than would be expected for nonoccupational noise-exposed persons of the same age and sex. As described in the National Occupation-al Research Agenda, problems created by occupational hearing loss include(1) reduced quality of life due to social isolation and unrelenting tinnitus,(2) impaired communication with family members, the public, and coworkers, (3) diminished ability to monitor the work environment (i.e., warning signals, equipment sounds, etc.), (4) lost productivity and increased accidents resulting from impaired communication and isolation, and (5) expenses for workers’ compensation and hearing aids. Although eliminating hazardous noise is the long-term solution to the noise problem, miners will likely need to rely on personal hearing protection in certain situations for quite some time. However, it is well known that noise attenuation provided by hearing protectors as they are worn during everyday use is usually quite different (i.e., worse) than when tested under lab conditions. In addition, workers may refuse to wear their hearing protection for any number of reasons. This project was initiated to evaluate practical technological advances in hearing protectors, with an emphasis on optimizing the balance between effectiveness, comfort, over protection, and communication ability. The recently completed auditory research facility is now under-going the accreditation process conducted by the National Institute of Standards and Technology under the National Voluntary Laboratory Accreditation Program. Experiments are planned to investigate the factors that affect a miner’s ability to hear hazard and warning sounds (e.g., roof working, alarm signals, spoken communications, etc.). A service contract has been initiated to record and digitally store samples of typical warning sounds heard in an underground coal mine. This information will be analyzed in the lab to develop recommendations that can be offered to the mining community regarding correct earplug/earmuff usage to maximize there cognition of hazard and warning sounds while adequately protecting the miners’ hearing.

Jan 12, 2001

By William L. Crentz

This study of the preparation characteristics of the coals in Indiana County, Pa., is the second in a series of Bureau publications appraising the Nation's coking-coal reserves by counties and the practicability of upgrading marginal deposits to metallurgical standards. The first publication dealt with the preparation characteristics of the principal coal beds in Cambria County, Pa. Over 95 percent of the coal remaining in Indiana County is in the Upper Freeport, Lower Freeport, and Lower Kittanning beds. Isolated patches of Pittsburgh-bed coal are present, and the Upper Kittanning bed is found in minable thickness at some locations, but production from these sources is not large. The greatest production is from the Freeport beds, which account for nearly 70 percent of the Indiana County coal output. These beds usually contain two or more shale or hone partings and in many places are high in sulfur. The large proportion of bony coal in the Freeport beds 'produces a relatively high-ash product. Mining practices vary from place to place, but it is frequently necessary to leave certain bony portions of the bed in place in order to load a satisfactory product. Table 1 shows the county's coal production, by beds, during 1948.

Jan 1, 1951

By Grant R. Brown

The report provides guidance for determining those environmental impacts associated with the surface mining of steeply pitching coal seams. In addition to the environmental impacts, four additional issues are addressed, namely (1) Time and motion studies of those coal mining systems employed in mining seams which pitch in excess of 250, (2) Assessment of those mining techniques, (3) Development of rationale for the mining methods employed, (4) Identification of the reclamation practices and determine whether these practices were in compliance with appropriate Federal and State regulations. Five surface mines located in three geologically distinct basins of the United States were analyzed during the period of August through November 1979. The three basins include the Hanna Basin of Wyoming, the North Park Basin of Colorado and the Southern Anthracite Field of Pennsylvania.

Jan 1, 1980

By M. Zaki El-Sabban

Tables of chemical thermodynamic properties for the ideal gas state from 0° to 1,000° K are reported for eight alkanethiols, three cycloalkanethiols and arylthiols, six thiaalkanes, two dithiaalkanes, three thiacycloalkanes, and three thiophenes. They are based on current physical and thermochemical constants and definitions, reliable vibrational assignments, and the latest insights into molecular structure and energetics.

Jan 1, 1970

Volume 2 presents the results of studies of Phelps Dodge Corporation's tailings embankments numbers 1West and 2 West, at Morenci, Ariz. The work involved compilation and description of pertinent factors relating to the physical features and operational characteristics of the facility, including information on embankment construction practices; investigation and research of the general geologic and seismicity characteristics of the site and vicinity; limited field exploration and materials sampling and testing at the site; installation and limited monitoring of piezometers, surface movement markers, and slope indicator casing; limited laboratory testing of materials to evaluate the basic index and engineering properties of the embankment and tailings materials; selected engineering analyses of the embankment for various types of potential "failure" conditions; and includes appendices.

Jan 1, 1974

By W. F. Wyman, S. F. Ravitz

"INTRODUCTION By far the greater part of the high-grade manganese ore used in the United States is imported from overseas. During the early part of the recent World War importations of manganese ore were seriously threated, and it appeared that it would be necessary to utilize low-grade domestic ores to the fullest possible extent. Among the processes that appeared to offer the best possibilities for beneficating low-grade domestic oxide manganese ores, which ordinarily are net readily amenable concentration by ore-dressing methods, were those involving leaching with sulfur dioxide. The Bureau of Mines therefore investigated the amenability of a large number of such ores to sulfur dioxide leaching.Several sulfur dioxide processes for beneficiating low-grade oxide manganese ores have been proposed. 3/ One of these, based on a patent by Van Arsdale and Maier, 4/ was used recently in a plant constructed to treat 1,000 tons per day of 20-percent manganese ore from the Three Kids deposit near Las Vegas, Nev. 5/ In this process the ore slurry is leached with sulfur dioxide gas, the resulting solution is evaporated to crystallize the manganese sulfate, the crystals are decomposed thermally to produce high-grade manganese oxide and regenerate sulfur dioxide, and the manganese oxide product is nodulized. The Bureau of Mines has recently developed a process 6/ in which a suspension of the ore in calcium dithionate solution is leached with dilute S02 gas, the manganese is recovered from the resulting solution by a simple lime precipitation, and the precipitate is nodulized or sintered to form a high-grade manga¬nese oxide product."

Jun 1, 1947

By Millard M. Gilkey

This Bureau of Mines report presents results of a detailed study of water usage in the Wyoming mineral industry along with projections for the future In 1964, the mineral industries of Wyoming used 20 billion gallons of new water, nearly all self-supplied, and reused 72 billion gallons, a total usage of 92 billion gallons. Consumption amounted to 2.8 billion gallons. About one-half of the 20 billion gallons of new water was obtained from [srface] sources and the rest from ground water. Reported costs, covering power and maintenance, for the self-supplied new water at mineral industry operations ranged from less than 1 cent to 20 cents per thousand gallons and aver-aged 8 cents. At one mineral-related operation, water was hauled by truck to supplement a well supply. The cost was $2.00 per thousand gallons delivered. However, the supplemental requirement was only 10 gpm. Cost figures for the recirculation of water, covering power and maintenance, averaged 2 cents. In terms of water usage, the value of product for the entire industry was $25 per thousand gallons of new water intake and about $180 per thousand gallons consumed. The study revealed that Wyoming has a water deficiency but that the shortage is less severe than in the arid Southwest. Projection of the water needs of the Wyoming mineral industries indicates that the demand for new water will increase from the 20 billion gallons used in 1964 to 25 billion gallons in 1980, a 25-percent increase. The projected new-water requirement for the year 2000 is 40 billion gallons, a 100-percent increase compared with the 1964 figure.

Jan 1, 1967

By Grant R. Brown

The report provides guidance for determining those environmental impacts associated with the surface mining of steeply pitching coal seams. In addition to the environmental impacts, four additional issues are addressed, namely (1) Time and motion studies of those coal mining systems employed in mining seams which pitch in excess of 25°, (2) Assessment of those mining techniques, (3) Development of rationale for the mining methods employed, (4) Identification of the reclamation practices and determine whether these practices were in compliance with appropriate Federal and State regulations. Five surface mines located in three geologically distinct basins of the United States were analyzed during the period of August through November 1979. The three basins include the Hanna Basin of Wyoming, the North Park Basin of Colorado and the Southern Anthracite Field of Pennsylvania.

Jan 1, 1980

By Zsuzsanna Zborovszky

A circuit is considered intrinsically safe when any spark or thermal effect produced normally (that is, by operating the equipment in its correct operational manner to fulfill its purpose) or accidentally (caused by short circuit, earth fault, defective components, breaking the wiring, etc.) is incapable under prescribed test conditions of causing ignition of a prescribed gas mixture. The test conditions and gas mixture should be at least as hazardous as the true parameters of the environment where the circuit will be operated. According to present practices, the question of whether or not a circuit is intrinsically safe is decided upon experimentally. The circuit is inspected first for mechanical soundness and a survey is made to determine what faults should be considered as probable. Then the individual branches are connected, in sequence, to a test apparatus called 'breakflash" which acts as an opening, closing contact and thus draws sparks from the circuit. This test is repeated a given number of times in the presence of the prescribed gas mixture under specified conditions (electrode configurations, gas parameters, etc.). The equipment will be regarded as intrinsically safe if during testing no ignition has occurred.

Jan 1, 1972

By Donald J. Keefe

The Remote Working Level Monitor (RWLM) is an instrument used to remotely monitor the Rn-daughter concentrations and the Working Level (WL). It is an ac powered, microprocessor based instrument which multiplexes two independent detector units to a single central processor unit (CPU). The CPU controls the actuation of the detector units and processes and outputs the data received from these remote detector units. The remote detector units are fully automated and require no manual operation once they are set up. They detect and separate the alpha emitters of RaA and RaC' as well as detecting the beta emitters of RaB and RaC. The resultant pulses from these detected radioisotope; are transmitted to the CPU for processing. The programmed microprocessor performs the mathematical manipulations necessary to output accurate Rn-daughter concentrations and the WL. A special subroutine within the program enables the RWLM to run and output a calibration procedure on command. The data resulting from this request can then be processed in a separate program on most computers capable of BASIC programming. The calibration program results in the derivation of coefficients and beta efficiencies which provides calibrated coefficients and beta efficiencies.

Jan 1, 1977

By R. R. Sayers

The increasing use of hydrogen fluoride (annual consumption now exceeds 500,000 pounds (1)4/) directly and its occurrence as a byproduct of the utilization of fluorine compounds in the mineral industries, especially in metallurgical processes and in the refining of petroleum products, has aroused interest in its toxicity, and a brief review of the literature, with special reference to the hazard of poisoning in the mineral industries, seems to be opportune. Recently, residents in the vicinity of aluminum plants have been complaining of injury to livestock and vegetation as well as to their own health from the gases discharged into the air during operation of the plants, hydrofluoric acid gas apparently being the offender. The comparatively recent utilization of hydrofluoric acid in the alkylation process for the production of high-octane gasoline has raised the question of the hazard of poisoning in the petroleum Industry. In addition, the use of fluorine-containing refrigerants has extended the potential al exposure outside of industry (2).

Jan 1, 1945