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By d&apos, Kathleen J. Amico

THIS SUMMARY appears in Minerals Yearbook volumes I and III, which cover mineral production in the United States, its island possessions, the Canal Zone, and the Commonwealth of Puerto Rico, as well as the principal minerals imported into and exported from the United States. The several commodity and area chapters contain further details on production. A summary table comparing world and U.S. mineral production also is included. Mineral production may be measured at any of several stages of extraction and processing. The stage of measurement used in the chapter is normally what is termed ?mine output." It usually refers to minerals in the form in which they are first extracted from the ground, but customarily includes for some minerals the product of auxiliary processing operations at or near mines.

Jan 1, 1965

By W. E. Robinson

Oil-shale samples selected from a core of the Green River Basin (Wyoming) were studied to ascertain differences in the composition and/or chemical structure of the organic material in the samples relative to stratigraphic position within the Green River Formation. This involved a systematic study of the soluble organic material and the insoluble kerogen present in the samples. Emphasis was placed upon the distribution of the alkanes (normal and isoprenoid compounds) in the soluble extract and upon the aromaticity of the kerogen. In general, it was concluded that significant differences exist in the chemical structure of the oil-shale organic material from various strata within the Green River Formation of Wyoming. Most of the compositional and structural changes were not related to burial depth but were related to source material variations, environmental differences, or other factors.

By F. Chase, D. Pappas

Pillar recovery has been associated with nearly one third of roof fall fatalities in underground coal mines during the past decade. Safe pillar recovery requires global stability and local stability. Global stability is addressed primarily through pillar design. The local stability risk factors include cut sequence, the final pillar stump, supplemental supports (timbers vs. Mobile Roof Supports (MRS)), roof bolting, and many others. The National Institute for Occupational Safety and Health (NIOSH) has evaluated each of these factors through field research and analysis of accident statistics. The paper discusses design methods and technologies that have been transferred to the mining community and implemented.

By D. Bienstock

A rig was constructed to burn 100 to 125 lb of coal per hour at 4,000° F in a cyclone burner with oxygen-enriched air preheated to 1,500° F to ascertain the problems in the coal-fired MHD generation of power. Potassium carbonate was added to the coal at several concentrations up to 1.23 g-moles/kg of coal (17 lb K2C03/100 lb coal). Boiler-tube materials maintained at wall temperatures of 800° to 1,500° F were exposed to the combustion effluent of 1,800° to 2,500° F. Practically complete removal of sulfur dioxide from the stack gas was achieved with the seed addition. Nitric oxide formation followed theoretical expectations at combustion temperatures with some decomposition of the NO occurring as the gas cooled flowing through the system. Nitrates in the fly ash were less than 1.7 percent of the total fixed nitrogen. With aqueous extraction of the fly ash a maximum recovery of 75 percent of the potassium was obtained. Haynes 25 was unattacked at a wall temperature of 1,500° F in combustion gas at 2,500° F; the stainless steels 310, 316, and 446 were resist-ant at a metal temperature of 1,100° F in gas at 2,100° F.

Jan 1, 1970

By T. E. Gray

This report describes the preparation characteristics of the significant coalbeds in Boone County, W. Va., as determined by the Bureau of Mines. It is one of a series describing the coals suitable for producing metallurgical coke, either as mined or after beneficiation. Over 6.3 million tons of coal was produced in Boone County, W. Va., in 1959, of which almost 5.5 million tons was mechanically cleaned in eight preparation plants. On December 31, 1959, it was estimated that almost 8 billion tons of coal remained in the county in beds 24 inches or more in thickness. Thirteen samples were collected from nine coalbeds and washability tests were made on these samples.

Jan 1, 1961

By d&apos, Kathleen J. Amico

THIS SUMMARY appears in Minerals Yearbook volumes I and III, which cover mineral production in the United States, its island possessions, the Canal Zone, and the Commonwealth of Puerto Rico, as well as the principal minerals imported into and exported from the United States. The several commodity and area chapters contain further details on production. A summary table comparing world and U .S. mineral production also is included. Mineral production may be measured at any of several stages of extraction and processing. The stage of measurement used in the chapter is normally what is termed ?mine output." It usually refers to minerals in the form in which they are first extracted from the ground, but customarily includes for some minerals the product of auxiliary processing operations at or near mines.

Jan 1, 1965

By H. K. Kutter

The pressure pulse generated by an underwater spark \vas investigated in relation to its potential use for rock fragmentation. The study established (1) the relation between the peak discharge current and the peak wave pressure; (2) the relationships among the peak wave pressure, the discharge voltage, and the spark gap width; (3) the type and pulse duration of the generated wave; (4) the percentage of energy transmitted in the spark as a function of spark gap width and discharge voltage; and (5) the percentage of energy converted into the pressure wave as a function of gap width and discharge voltage. Spark-generated fractures were studied in two-and three-dimensional rock and plastic specimens. The laboratory results indicated that the pressure pulse generated by an underwater spark is a potential practical tool for rock fragmentation. The paper contains an appendix describing the capacitive pressure gage specially developed for the laboratory tests.

Jan 1, 1969

By G. E. Rennick, F. E. Armstrong, J. Pasini, J. R. Abrams

An oil well penetrating the Pittsburgh bituminous coalbed in northern West Virginia was plugged and safely mined through 3 months later. A sensitive chemical tracer, introduced into the oil reservoir before the test, was not detected in the mine air following the plugging and during mining of the pillar and penetration of the well. Effectiveness of the plugging in preventing reservoir gas from entering the mine through the well hole was verified by continuous monitoring of the mine air for indications of sulfur hexafluoride, an inert gas detectable in amounts as minute as 112 part per billion. Expand- able cement and fly ash-gel-water slurry were utilized to seal the well above and below the coal seam. Three other wells were also plugged using various techniques.

Jul 1, 1972

By Thomas J. Peters

In 1988, at the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines studied the 5,640-acre Soda Mountain Wilderness Study Area (OR-011-017), in order to evaluate its identified mineral resources. The study area is located in Jackson County, OR, about 30 miles south-east of Medford. The study area covers most of the south-facing slope of 6,071-ft Soda Mountain. Geologically, the area is underlain by Oligocene to Pliocene basaltic andesite flows and less extensive intrusive rocks of the western Cascade Mountains. In addition, there is a 3/4-mile-diameter area of kaolinized and silicified rhyolite tuff, which appears to have intruded the andesite, and is host to epithermal gold mineralization.

Jan 1, 1989

By Terry J. Close

The highly-mineralized 43,700-ha Rapid River study area, on the southeast side of Hells Canyon Wilderness and west of the village of Cuprum, in Adams County, western-Idaho, was investigated in 1992 by the USBM (U.S. Bureau of Mines) in conjunction with its Idaho Land Assessment Program. The 1992 study updated data gathered during the USBM's 1974-76 Wilderness investigation. The studies consisted of the evaluation of 61 mineralized sites and the estimations of tonnages, grades, and minability of these sites. Most of the sites studied are in two mineralized locales--Windy Ridge and Jackley Mountain. A few isolated sites, peripheral to the two locales, were also examined. The 61 sites contained more than 340 mine and prospect workings, including about 10,300 meters (34,000 feet) of underground workings, plus 134 drill holes.

Jan 1, 1993

By C. A. Wilson

The Bureau of Mines started a continuing program to investigate and evaluate analytical techniques to assist governmental agencies to select simple, rapid, reliable methods for crude oil spill identification. Six crude oil samples were analyzed to evaluate gas-liquid chromatography, atomic absorption spectrophotometry, infrared spectoscopy, sulfur and nitrogren determinations, mass spectrometry, nuclear magnetic resonance spectroscopy, and ultraviolet spectrophotometry. Samples were studied from the following selected fields: El Morgan, Egypt; Duri, Indonesia; Minagish, Kuwait; Bachaquero, Venezuela; Gach Saran, Iran; and Prudhoe Bay, Alaska. These samples were chosen to represent high-production fields that are likely to be involved in oceanic transport. Over 50 years of Bureau of Mines analytical research on petroleum served as the basis for evaluation of the experimental results to determine which of the methods are effective techniques to identify crude oil spills. Gas-liquid chromatographic analysis, atomic absorption spectrophotometric analysis, and sulfur-nitrogen determinations are recommended as the most useful of the techniques investigated.

Jan 1, 1975

By R. V. Lundquist

Past reports by the Bureau of Mines have described the extraction of alumina from numerous aluminum silicate materials by the lime-soda sinter process. The results from pilot-plant investigations of six materials, with alumina-to-silica mole ratios from 0.3 to 8.7, indicated a relationship between the alumina-silica ratios and the processing characteristics of the sinter. A series of laboratory tests was conducted to define this relationship. Sinter and leach tests determined that an alumina-to-silica mole ratio of 0.90 or greater resulted in the best alumina and soda recoveries while leaving the leach slurries practically free from any tendency toward gelation. The widely different chemical and mineralogic properties of the various aluminous materials used in compounding the mixes had no perceptible effect on the leaching characteristics of the sinter. The blending of low-cost, high-alumina materials with aluminum silicate materials to give an alumina-to-silica mole ratio of 0.90 or greater would improve alumina and soda extraction and minimize operating problems in the lime-soda sinter process.

Jan 1, 1970

By J. E. Zeilinger

This Bureau of Mines report describes the preparation characteristics of the significant coalbeds of the Ohio coalfield. Washability analyses were made on 39 coalbed samples collected from a 14-county area. None of the samples were of metallurgical quality as received. Nine of the samples could be sufficiently upgraded to produce metallurgical-grade products, and the remaining 30 samples could not be upgraded to this quality because their sulfur contents could not be lowered to meet the standard. For steam or power generation, 10 of the samples were of medium sulfur content as received and one could be upgraded to a low sulfur content. Of the 29 samples having a high sulfur content as received, 18 could be upgraded to a medium sulfur content. The original sulfur content of the other 11 samples having a high sulfur content as received can be appreciably reduced by removal of the sink 1.58 specific gravity material; however, these coals would be classified as high sulfur coals both before and after removal of the sink 1.58 specific gravity material.

Jan 1, 1972

By Doris M. Hyde

Mineral industry activity in many of the smaller Caribbean Island countries has remained minimal. For this reason, specific references to Bermuda, Guadeloupe, Martinique, and the Netherlands Antilles have been removed from textual and trade table presentations. Any significant future developments will be reported as they occur. Readers are referred to earlier Minerals Yearbook editions for previous information. Table 1 production statistics have been modified in some instances. References to certain nonmetal commodities were eliminated because information has often been unreliable. Their inclusion in table 1 was not considered important to either an overview of the area or to compatibility with volume I of the Minerals Yearbook.

Jan 1, 1984

From the National institute for Occupational Safety and Health Disasters take many forms and demand quick response from emergency workers. They may include natural disasters such as earthquakes or hurricanes, or they may involve manmade disasters such as technological failures or terrorist attacks. As a member of an emergency response team, you and your team members are at risk of experiencing what psychologists refer to as a traumatic incident—an incident that may Involve exposure to catastrophic events, severely injured children or adults, dead bodies or body parts, or the loss of colleagues, for instance. Traumatic incidents can produce unusually strong emotional reactions that may interfere with your ability to function at the scene or later: You may experience any of the physical, cognitive, emotional, or behavioral symptoms listed below in Table 1. Some people experience emotional aftershocks weeks or months after they have passed through a traumatic event. Others may experience these reactions while still at the scene, where they must stay clearly focused on constantly changing hazards to maintain their own safety and to rescue injured victims.

This chapter presents data on occupational exposures from several sources. Data from compliance samples obtained by MSHA inspectors are presented in table 6-1 for coal mine dust and silica dust, and in tables 6-2 through 6-6 for metal fumes. Since these samples were taken for compliance monitoring rather than as part of a survey of the industry, it is difficult to predict how well they indicate actual exposures for all mining operations. In the coal industry, 7.8% of all respirable dust samples during 1986-1995 were above the permissible exposure limit (PEL). Of silica dust samples obtained during the 10-year period, 23.7% were above the PEL in coal, 16% in metal, 10.8% in nonmetal, 9.1% in stone, and 7.6% in sand and gravel. Of metal fume samples, silver samples showed the largest percentage above the PEL-approximately 48% of samples in both metal and nonmetal. Tables 6-7 and 6-8 present data on noise exposures from the MSHA "dual threshold" survey, which was published in the Federal Register [61 Fed. Reg. 66347 (1996)] as part of a proposed rule change for occupational noise exposure in mining. This study examined a group of samples obtained during 1991-1995 and compared the percent of samples that were above two separate specified limits. The first limit was the current noise standard, a time-weighted average of 90 dBA, calculated to include only exposures at 90 dBA and above. The second limit was a time-weighted average of 85 dBA, calculated to include exposures at 80 dBA and above. Tables 6-8 and 6-9 refer to musculoskeletal overload conditions examined in the National Occupational Health Survey of Mining (NOHSM) [NIOSH 1996]. Table 6-8 shows the operational definitions for each condition; table 6-9 shows the percentage of the workforce potentially exposed, by commodity. Across all commodities, a large proportion of workers were exposed to musculoskeletal overloads due to positioning of the neck and back; positioning and motion of the forearms, arms, and shoulders; heavy lifting; and positioning and movement of the lower limbs. The recorded overloads were defined in the survey and did not exceed any NIOSH, MSHA, or OSHA guidelines for musculoskeletal overloads. Further information on this survey appears in appendix A.

Jan 5, 2000

By C. Stephan, E. Weiss, J. Trackemas, M. Sapko

The National Institute for Occupational Safety and Health (NIOSH), Pittsburgh Research Laboratory (PRL), in collaboration with the Mine Safety and Health Administration (MSHA), the mining industry, and seal manufacturers recently conducted a series of full-scale experiments within the underground experimental mine at PRL’s Lake Lynn Laboratory. The purpose of the experiments was toe valuate the explosion-resistant characteristics of several new seal designs for rapid deployment during mine emergencies. These seals can be deployed in 6 to 10 hr and are capable of with standing explosion overpressures in excess of 140 kPa (20 psi). These novel seal designs use available mine materials, do not require conventional rib hitching, and, most importantly, can substantially reduce exposure time for coal miners during sealing and mine recovery operations.

By Dennis R. Dolinar, Eric R. Bauer

Skin failures of roof and rib in underground coal mines continue to be a significant safety hazard for mineworkers. Skin failures do not usually involve failure of the support systems, but result from rock or coal spalling from between the support elements. For instance, in 1997 more than 800 miners were injured by roof and rib falls, of which 98% were the result of skin failures [Bauer et al. 1999]. Also, nearly 80% of the roof and rib failure injuries occurred at or near the working faces in development sections. The face area is a zone where the potential for skin failure accidents and injuries and for roof and rib failures is high because of mining activity, ground readjustment due to changing stress conditions, and the higher exposure of mine workers. In addition, failures occur where the roof and rib are unsupported. This paper reviews the roof and rib accident statistics resulting from skin failure, and highlights the incidences by type, numbers and percentage, in-mine location, supported and unsupported roof, and worker activity at the time of injury. Also discussed are the causes of roof and rib skin failures, current and improved support methods and materials for skin surface control, and machine design modifications for improved roof bolter operator protection. It also reviews the historical literature on skin failures and control methods.

Jan 10, 2000

By Charles E. Whieldon

This report presents the results of a study on part of the Smithfield oilfield, Wetzel County, W. Va. The primary purpose of the investigation was to determine the original and the present volume of stock-tank oil in the formations and to investigate the feasibility of waterflooding the Gordon Stray, Gordon, and Fourth sands underlying the I. D. Morgan lease. The study was based on laboratory core analyses, geophysical well logs, geologic considerations, and various field prediction data from the I. D. Morgan lease. The Bureau found that, of the three sands cored, the Gordon Sand was the best prospect for waterflooding, and that a properly engineered water flood should recover 136 to 230 barrels of oil per acre-foot from this formation.

Jan 1, 1967

By Oliver C. Fursman

The Bureau of Mines undertook this investigation to study methods of utilizing red mud residues from production of alumina from bauxite. Pilot-plant tests were conducted using Jamaican and Surinam red muds. Both the carbon-lime-soda sinter process and electric-arc smelting with coke and limestone were employed to recover iron and alumina. Alumina recoveries of 85 to 90 percent were obtained by the sinter process; although iron recovery was about 80 percent, the magnetic product was finely divided and difficult to separate from the gangue. Smelting red muds in the electric-arc furnace produced a pig iron with 98-percent recovery of iron; up to 84 percent of the A1203 was recovered by leaching the calcium aluminate slag with Na2C03 solution. A titania product assaying 96 percent TiO2 was recovered from the nonmagnetic portion of Surinam red mud sinter by extraction with H2SO4. Leached calcium aluminate slags and brown mud (from the combination Bayer process) are possible raw materials in the manufacture of portland cement.

Jan 1, 1970