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By James L. Elder, J. P. Capp, James J. Dowd

The Bureau of Mines and the Alabama Power Co., jointly, conducted the first experiment undertaken in the United States in underground gasification of coal in place, at Gorgas, Ala. Milton H. Fies, manager of coal operations, Alabama Power Co., proposed the cooperative investigation to Arno C. Fieldner, chief, Fuels and Explosives Branch, Bureau of Mines; and assisted in supervising the experiment. The objectives of the experiment were to determine whether coal in place could be burned successfully and whether the burning could be controlled; the effect of the fire on the coal bed and the overlying strata; and the yield and quality of gas that could be obtained.

Aug 1, 1947

In 1987 Wyoming became the largest coal producing state in the country. The state is known for its extensive coal resources and extremely thick coal seams. Wyoming's coal reserves total about 69.3 billion tons, or 14.2 percent of the U.S. coal reserve. Coal seams range generally from 10 to 80 feet in thickness, although one seam is 220 feet thick. The coal-bearing areas of Wyoming underlie approximately 41 percent of the state's total land area. Wyoming's coal ranges from lignite to high volatile bituminous. Most of the coal produced is subbituminous from the Powder River coal region near Gillette. The presence of coal in Wyoming was discovered before 1834 on the Belle Fourche River. The state's first mine opened in Carbon County in 1865, and with the completion of the trans- continental railroad, the demand for coal increased. Currently approximately 80 percent of Wyoming's coal production is shipped out-of-state to meet the growing demand for low- sulfur coal to fuel electric generating plants. Wyoming received conditional regulatory approval November 26, 1980. Its Abandoned Mine Land Program was approved February 14, 1983.

Jan 1, 1992

In This Chapter [Finding the dust source Ventilation and dust collector malfunctions Upgrading the dust controls Design stage ventilation planning ] This chapter explains how to reduce respirable dust76 in hard-rock tunnels during excavation by using tunnel boring machines (TBMs). The first steps in combating a dust problem are to take dust samples to pinpoint the source, check the ventilation system, and check the dust collector. If the ventilation system and dust collector are operating properly, then other dust controls such as water sprays and conveyor belt scrapers must be upgraded. For tunnels in the design stage, recommended air quantities are provided. FINDING THE DUST SOURCE AND LOOKING FOR VENTILATION MALFUNCTIONS [The first steps in fighting a dust problem are to take dust samples to pinpoint the source, check the ventilation system, and check the dust collector. Without knowing the exact source, efforts to reduce dust are hit-and-miss (mostly miss).] Taking samples to pinpoint the dust source. In tunnels with high levels of airborne dust, the first task is to pinpoint where the dust enters the airstream. Most dust originates from rock breakage at the tunnel face, but the location where this dust enters the airstream can vary. Dust can leak from behind the TBM face shield, from gaps in the ventilation duct, or from a mal-functioning dust collector. It can be entrained into the air from the muck on a moving conveyor belt. It can even be shaken loose from the underside of the belt as it passes over the idlers. As a start, to locate the dust source, dust samples and air quantity measurements should be taken at the following locations:

Jan 6, 2003

By G. Roger Miller, Kristine M. Krajnak, Stephen S. Leonard, Stacey Waugh

Repeated exposure to hand-arm vibration through the use of vibrating hand tools can result in the development of the disorder known as hand-arm vibration syndrome (HAVS; (1,3)). One of the hallmark symptoms of HAVS is cold-induced peripheral vasospasms that result in finger blanching (4). Although the vascular and neural pathology associated with vasospasms has been described, little is known about cellular mechanisms leading to this damage (4). To understand how vibration may alter vascular and neural physiology and anatomy, rats were exposed to a single bout of tail vibration and the molecular responses of neural and vascular tissues were measured to determine if there are immediate or sustained affects of vibration that may underlie longer term changes in physiology. Methods Experiment 1. Male Sprague Dawley rats (n = 32, 6 weeks of age) were housed in AAALAC accredited facilities. All procedures were approved by the NIOSH Animal Care and Use Committee and were in compliance with the CDC guidelines for care and use of laboratory animals. Vibration exposures were performed by restraining rats in Broome-style restrainers, and securing their tails to a vibration platform using 6 mm wide straps that were placed over the tail every 3 cm. Restraint control rats were treated in the same manner, except that the tail platform was mounted on isolation blocks and not on a shaker. The vibration exposure was 125 Hz, 49 m/s2, for 4 h. Rats were euthanized with an overdose of pentobarbital (100 mg/kg) 1 h or 24 hours after the exposure. RTqPCR was used to measure transcript levels for endothelin 1 (ET-1), the 3 forms of nitric oxide synthetase (NOS) NOS-1, NOS-2, NOS-3 and norepinephrine receptor subtypes 1D, 2A, 2C, in artery tissue, and to measure calcitonin gene-related peptide (CGRP) and nitric oxide synthase-1 (NOS-1) in ventral nerves. Data were analyzed using 2-way ANOVAs. Experiment 2. Male Sprague Dawley rats (n =24, 6 weeks of age) were maintained as described above. Animals were exposed to a single bout of restraint or vibration. Another group of animals served as cage controls. All animals were euthanized 24 h after the exposure, and tail arteries were isolated and frozen. Reactive oxygen species ROS) were measured using electron spin resonance spectroscopy (ESR). Arteries were homogenized over ice in 1 ml of PBS with protease inhibitor cocktail, using a tissue tearer (Biospecs Products Inc. Racine, WI USA). The sample was split into two 0.5 ml samples. One set had PBS and the spin label hydroxyl-TEMPO [0.1 mM] added while the other set had hydroxyl-TEMPO [1.0 mM] plus the specific hydroxyl radical scavenger, dimethylthiourea (DMTU), added to confirm the presence of the hydroxyl radical. Samples were vortexed and then placed in a flat cell for ESR analysis. The ESR spectrometer settings were: receiver gain, 6.32 x 102; time constant, 0.02 s; modulation amplitude, 1.0 G; scan time, 20 sec; magnetic field, 3490 ± 100 G (2). Data were analyzed using 1-way ANOVAs.

Jan 6, 2006

By John P. Wagner

The details of a three-phase study (total time period of 12 months) entitled ?Fire Alert Systems for Metal and Non-Metal Mines,? are presented. Phase 1 consists of a state of the art survey on fire detection devices and gas sensing techniques. Phases 2 and 3 include laboratory screening and systems concepts testing on various detectors classified as products of combustion, optical view-field and contact (or thermal) types under incipient and flaming combustion conditions. Recommendations for a mine fire detection system to protect shaft, sealed off or mined out (from spontaneous combustion of sulfide containing ores and cellulosic materials), and fuel storage areas are also included. me principal problem area noted during Phase 1 study is the high expected occurrence of false alarming of products of combustion detectors (POC") subjected to normal mining operations---diesel vehicles and equipment and shot firing or blasting operations. Simultaneous gas sensing of either the ratio of CO/NOx or CO2/NOx with detection of one or more fire signatures (smoke, radiant energy, or heat sensing) is the recommended approach to discriminate against these operations.

Jan 1, 1975

By J. R. Thoenen

In Progress Report 1,4/ a number of facto mere demonstrated and conclusions drawn from experimental tests and records made during commercial blasting operations at a number of quarries. For example, the tests showed (1) that vibrations received on outcrops were of comparatively

Jan 1, 1938

By P. S. Haury, Thomas C. Denton

"INTRODUCTION AND RESUMEThe Reward zinc property was one of the first selected for exploration by the Bureau of Mines at time when zinc supplies for war production were very short. Preliminary examination indicated that an appreciable tonnage of zinc that could be developed for early production might be found by diamond drilling. The geology was mapped by the Federal Geological Survey, and 14 holes were diamond drilled by the Bureau of Mines. This work was started in September 1942 and completed in September 1943.The Reward is an old property in southwestern Pinal County, 26 miles from Casa Grande on the Southern Pacific Railroad. Mining was begun in the early 1880's and was continued intermittently by several operators to about 1917. About 400,0oo pounds of copper was produced from the north¬eastern part of the property, mainly from a 600-foot incline in oxidized copper ore that replaced a bed of limestone. This ore was mined out. A 400-foot vertical shaft in the copper area was inaccessible. A 325-foot vertical shaft had been sunk near the southwest end of the zinc-bearing area, and a 600-foot crosscut tunnel had been driven near the northeast end of the zinc area, but little zinc ore was produced. There were several shallow inclines and numerous surface pits between the main workings.The ores were deposited in Paleozaic limestones that strike northeast and dip about 40 degrees northwest. These are capped by Cretaceous clastic and volcanic rocks in the zinc area. The outcrops show mineralization in a segment of the limestone 4,500 feet long, which is limited by large cross faults at each end. Another large fault, which strikes north, separates the northeast third of the mineralized belt from the remainder. Copper predominates northeast of this fault and zinc southwest of it. The ore beds are cut by numerous small cross faults. Ore was deposited for short distances along some of these, but more of it made out from the fissures along certain replaceable limestone beds."

Nov 1, 1946

By John R. Benham

The Windigo Theilson RARE II area has a low mineral potential. There are no mines or claims in the area. The only observed results of mining activities were five prospect pits near Tolo Mountain. Samples from these pits contained no significant assays. The study area contains more than 190 million cu yds (145 million m3) of cinders in 17 cones. Development of these cinders is unlikely because their locations are remote, and other sources supply area needs. The Geological Survey has classified the area as prospectively valuable for geothermal resources. However, there has been no geothermal exploration activity.

Jan 1, 1982

By A. J. Fejes

The purpose of this Bureau of Mines report is to provide mining industry personnel and regulatory authorities with a subsidence-reference list and annotated bibliography that will aid them in locating subsidence information and in developing their own subsidence information sources. Over 700 references are listed in the Bureau's subsidence information center bibliography; approximately 600 of these references were obtained for assessment. Of these 600 references, 167 were selected to be rated, categorized, and annotated. All literature referenced in this report was published prior to 1984. Table 1 is a cross - referenced index that classifies and rates selected references with respect to specific keywords. References are rated not on quality of content but rather on applicability to given subject areas. Appendix A is an annotated bibliography of the references listed in table 1 and provides further information of each article to aid the user in selecting articles for specific areas of subsidence technology. Appendix B is a copy of the subsidence information center bibliography.

Jan 1, 1985

By William M. Knuth

This study involved a review of bonding and bond release practices in the states of the Eastern and Midwestern Coal Provinces. Data was collected from regulatory authorities and site visits to document the bonding and release procedures in the states related to achieving successful reclamation. The regulations related to PL95-87 were reviewed. The analysis included suggested modified or new bond release criteria, a review of applicable bond release inspection techniques was prepared, a conceptual graduated bonding system and incentive procedures for reclamation of surface mine sites to alternative or higher land uses. A number of conclusions and recommendations for further research were included. A detailed bibliography and a glossary are included in the report.

Jan 1, 1978

A computer system for calculating the illumination on coal mine surfaces due to machine-mounted lights is described. Utilizing numerical models of mining machinery and measured data on luminaire output characteristics, the program computes the ft-candle levels incident on the mine entry surfaces for any desired machine/luminaire/ entry configuration. Shadowing effects of the machine are taken into account. Results are provided at 2 ft. intervals on the face, left and right walls, floor and roof. The system operates, interactively from a Tektronix 4014 graphics terminal which handles all input/output functions. The software is installed on a Cyber 74 computer that communicates with the terminal via telephone line.

Jan 1, 1978

By A. D. Hahn

This report describes and gives the results of an examination by the Federal Bureau of Mines of ilmenite-bearing placer sand deposits in the 24-mile long valley of Otter Creek, Kiowa and Tillman Counties, Okla. Drilling and sampling was completed in three periods between October 1956 and September 1957. Mineralogic studies and mineral-dressing tests on recovery of ilmenite and other heavy minerals from composited samples of the sands were made in Bureau of Mines laboratories at Rolla, Mo., in 1957 and early 1958. Otter Creek rises in and drains the southwestern extremity of the Wichita Mountains, which are represented locally by knolls and ridges of gabbro and granite surrounded by plains floored with flat-lying Permian red beds. The valley fill consists of a basal sand-clay component, derived from weathering of the igneous rocks, and an overlying silt-clay alluvium. Ilmenite is present in significant quantity and recoverable grain size only in the basal sand-clay.

Jan 1, 1960

"These tentative coal mine inspection standards have been prepared as a guide for the Federal inspection of coal mines of the United States. Much time and thought have been spent by various members of the Safety Division in the preparation of thses standards, and it is believed that compliance with them eventually will be possible in most mines. In many instances objections will be raised to them owing to long-established mining customs and practices that are inherently of dubious safety and to a natural inclination to oppose change. In other instances there will be valid objections due to conditions not foreseen at the time these standards were prepared. Or there may be substandard conditions and practices due to original mine layouts that it is not practicable to change during the lifetime of the mine; in such instances it is likely that some effective measures are or can be taken toward lessening hazards.With the rapid change in mining methods some of the standards may become inapplicable and it may be advisable to revise them to meet the new conditions. Therefore, questions regarding these standards and suggestions regarding new standards should be brought to the attention of the supervising engineer of the Coal Mine Inspection Division so that modifications of and additions to these standards may be made from time to time.In many respects these standards exceed the provisions of the various State mining laws, and some may conflict with the laws of some States. In cases of conflict, the intent is not to advocate noncompliance with State laws but to suggest that it may be desirable for the State to reconsider such laws or safety orders.Although an effort has been made to word these standards so that they may be readily understood, nevertheless, a reasonable interpretation should be placed upon them. In fact, in numerous instances the words reasonable"", ""suitable"", and ""properly"" are used in recognition of the fact that reason- and sound judgment enter into the carrying out of the safety endeavor.The policy of the Bureau on some vitally important safety matters in mines is set forth in its published Safety Decisions. These decisions have been consulted and used in the preparation of these standards. These decisions also are now being reexamined by its Mine Safety Board."

Feb 1, 1942

By W. P. Diamond

The direct method test was developed for general mine safety applications by the U.S. Bureau of Mines in the early 1970's to measure the gas content of coal samples obtained from the relatively shallow depths of eastern U.S. coal mines. Over time, applications for gas content data evolved which required increasingly accurate desorption values. It became evident that some of the inherent weaknesses in the original direct method test could best be addressed by abandoning the water displacement based desorbed gas volume measurements. The ideal gas law based modified direct method (MDM) and associated desorbed gas volume measurement apparatus was developed to provide the most accurate desorption values possible for rock samples obtained from any gas-bearing strata. The MDM has a number of significant advantages, including: (1) increased accuracy, especially for low gas content samples, (2) a test apparatus with an integral sampling port to facilitate the collection of uncontaminated gas samples, (3) an inherent head space effect correction in the periodic MDM desorbed gas volume calculations, (4) measurement of positive and negative desorbed gas volumes, (5) elimination of differential gas solubility effects as a source of error inherent in the water displacement methods, and (6) a compact and rugged test apparatus that along with the elimination of the ?glassware? required for the water displacement methods, facilitates its use in the field.

Jan 1, 2008

By D. A. Elkins

Design plans and detailed cost estimates of mining and treating ore from Maggie Canyon deposit by two alternative methods which can be used in the event of a sudden need to exploit this resource are given . Lower costs are estimated for the operation employing oil - emulsion flotation . The total capital investment required for this operation is estimated at $ 11,750,000 . Assuming an 85 percent recovery in mining , 55.6 pct of the manganese in the ore reserve would report in 153,333 tons of ferromanganese containing 75 pct manganese . The production cost for the 5 - year operation would be about $ 245 per ton of ferromanganese . The total annual operating cost would be approximately $ 7.5 million , distributed , in pct , as follows : Mining 11.9 , milling 24.4 , sintering 9.9 , smelting 47.2 , hauling ore and sinter 2.8 , and general offices 3.8 . Recovery and costs are both higher for the operation employing dithionate leaching . In this operation the required investment is about $ 17,220,000 . Manganese recovery would be 67.6 pct in 186,160 tons of ferromanganese . Production cost would be about $ 284 per ton of ferromanganese . The total annual operating cost would be about $ 10,575,000 , distributed , in pct , as follows : Mining 8.4 , milling 44.4 , sintering 7.4 , smelting 34.7 , hauling ore and sinter 1.3 , and general offices 3.8 . Potential process modifications might reduce the operating cost of the first operation by as much as 7 pct and that of the second operation by as much as 9.5 pct , but exploitation of the deposit by the techniques studied is not economical today .

Jan 1, 1964

To provide an engineering solution to wood crib design and deployment strategies that will ensure safety for underground coal mine workers. This is accomplished by preserving necessary ground control requirements while minimizing support costs or by developing new support strategies to enhance ground support in difficult conditions. A secondary objective is to be able to quantify wood crib support performance to define support requirements for alternative support systems. These objectives have been achieved through a simple-to-use computer program called the wood crib performance model (wcpm).

Jan 1, 1997

By Martin Hertzberg

This Bureau of Mines report analyzes diverse observations of the rates and mechanisms for the pyrolysis and devolatilization of coal and polymethylmethacrylate (PMMA). New data are presented for PMMA, together with new morphological evidence for the microscopic structure of the pyrolysis and devolatilization wave front in coals. It is concluded that there is no substantive evidence to support the traditional viewpoint that the pyrolysis and devolatilization rate process occurs isothermally, under chemical rate control; or is described realistically by a classical, unimolecular Arrhenius function of temperature. Instead, the reaction process occurs as a highly nonisothermal, heat-flux-driven, pyrolysis and devolatilization wave front, whose speed of propagation is predictable by internal heat transport constraints. Except for the complication of its charlayer residue, whose increasing thickness insulates the pyrolysis wave front from the heat source flux that drives it, both coal and PMMA behave similarly during pyrolysis and devolatilization. For PMMA, decomposition occurs at a temperature of 3500 to 5500 C; for coal it occurs at 4500 to 6000 C. There is no evidence that the reactant temperature ever exceeds those values regardless of the source temperature to which the samples are exposed.

Jan 1, 1988

By John D. Spencer

Air and water pollution and land reclamation relating to coal mining and utilization continued to be featured in research and technologic work on coal by the Bureau of Mines in 1967. Details of the environmental studies are given in this report, along with accounts of other research relating to the mining and utilization of coal. Other studies that were continued during 1967 included health and safety, mine explosives, coal preparation and transportation, coal utilization processes, chemistry and properties of coal, inspection and analysis, and inter-national activities. Publications issued in 1967 are cited throughout the report and in appendix C. Bureau of Mines research centers and laboratories are listed in appendix A, and organizations contributing to or cooperating in the work, in appendix B.

Jan 1, 1968

By A. M. Dale, J. Standeven, B. Evanoff

We encountered several areas of methodologic uncertainty during development of a data collection method for use with vibrating hand tools in metal assembly. A local manufacturer sought our assistance designing a data collection method for evaluating and predicting risks of upper extremity disorders associated with use of vibrating hand tools. Current methods of vibration measurement are described in ISO 5349 [2]. However, the complexity of measuring vibration along with other exposures such as force and posture has limited the number of workplace-based studies of upper extremity disorders that have included direct measurements of vibration. Data from this preliminary study was used to look at two issues: a comparison of vibration values between production and non-production workers when performing the same task, and a comparison of worker ratings of vibration comfort to direct measurement of tool vibration. Methods Eight experienced production workers used each of six metal fastening tools to install fasteners. Vibration was collected by 3 tri-axial accelerometers, one attached to the tool handle following ISO 5349 recommended locations, one attached to the hand dorsum on the 3rd knuckle and one to the thumb side of the wrist. Data sampling rate was 10,000 samples/second. Hand grip and feed forces were obtained using a Novel pressure sensing mat on the palm. Each trial consisted of installing 10 fasteners per tool for each of the 6 tools. The test set-up placed the wrist in the position typically used by the operator during production. Each worker documented subjective comfort and effort ratings on a seven point scale following each series of fastener installations. One series of testing was completed by three non-production workers inexperienced in fastener installation to simulate use of alternative employees for data gathering. Vibration data for each trial were acquired, digitized, and stored using Lab View. The X, Y, & Z axes were used to calculate the vector sum response for each tri-axial accelerometer. The tool data were digitally filtered following ISO recommendations. Calculated data consisted of the mean RMS over the tool’s on- time, the starting and breaking peak impulses, and the peak of the frequency response. Results Production workers (n=8) were right hand dominant males with a mean age of 55 years and normal hand strength (mean right grip = 106 lbs). Non-production workers (n=3) had similar characteristics. We found large and statistically meaningful differences in hand force during tool use between production and non-production workers (mean production workers = 9.77 lbs, mean non-production workers = 43.30 lbs, p = 0.0001). Vibration values obtained from the hand also showed a statistically meaningful difference (mean in production workers = 0.67 Gs, mean in non-production workers = 1.48Gs, p = 0.0014, figure 1). Experienced worker ratings of comfort during tool use demonstrated a moderate correlation with measured vibration (r=0.63). Worker ratings trended with direct recordings from the tool handle as shown in figure 2.

Jan 6, 2006

By B. W. Moore

The U.S. Bureau of Mines investigated the separation of heavy rare-earth elements (REE) in an ion-exchange process. An ion-exchange column consisting of two sections, a loading section and a separation section, provides high levels of REE loading and good REE separation with an expected processing cycle of less than a month, while current ion-exchange technology requires more than 5 months. A different resin is used in each section: sulfonic resin in the loading section and iminodiacetic resin in the separation section. The separation section is further divided into two segments: the first conditioned with NH4 and the second with acid. Erbium is loaded onto both segments of the separation column as a retaining ion. Bands of mixed REB eluting between separated bands of pure REB were recycled directly to the column. Without mixed-band recycle, over 80% of the REE eluted from the column was separated into fractions with 99% purity of each element; with such recycle, the percentage of separated elements can be increased to around 90%.

Jan 1, 2010