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By James A. Powell

The theory of electromagnetic fields indicates such fields could be used to detect and locate trapped miners. To be useful, the hardware of the system must meet a number of requirements, including small size, intrinsic safety, and rugged construction. Such hardware has been built, and the system has been tested by the Bureau of Mines and its contractors. These tests indicate that the electromagnetic method provides a practical means to locate miners in emergencies.

Jan 1, 1976

Roof screening for ground control originated with metal miners in the western United States. At first chain-link fence was used, but because it was so difficult to handle, the miners started installing a more rigid welded wire screen used in the concrete industry. Eventually coal mines in the west began to use screen, and now more and more coal operations, especially longwall mines, are installing roof screen on a regular basis. Screen use has recently increased in the Illinois basin and is now making its way to underground coal mines in the eastern U.S.

By F. R. McDonald

The compound ?-valerolactone has been identified in an acid fraction isolated from waste water collected from an in situ oil-shale retort. Infrared, nuclear magnetic resonance, and mass spectrometry were used by the Bureau of Mines to confirm the identification of a subfraction collected from a gas chromatograph.

Jan 1, 1974

By G. R. Hopkins, E. W. COCHRANE

According to reports received by the United States Bureau of Mines , Department of Commerce , as of January 1 , 1930 , there were 412 completed refineries in the United States with a daily crude oil capacity of 3,755,585 barrels . This compares with 413 refineries of 3,509,540 barrels capacity on January 1 , 1929 , which indicates that whereas the number of refineries was practically unchanged , the total capacity increased 8 per cent during the past year . Of the completed plants as of January 1 , 1930 , 358 plants , of 3,634,825 barrels total capacity , were operating and 54 , with a capacity of 130,760 barrels , were shut down . Compared with a year ago , this indicates a decline in the percentage of the total refinery capacity that is inoperative . There has been a decided decrease in the number of shut-down plants since 1924 and 1925 , when one plant in every three was inoperative . Many of the inoperative plants of 1924 and 1925 were constructed soon after the boom times of 1920. Some of these were operated for a time but were unable to show a profit during 1923 and 1924 , when an overproduction of crude petroleum was accompanied by demoralized markets for refined products . Prices for refined products improved in 1925 and 1926 , but only a comparatively few of the shut -down plants , then partly obsolete , were able to obtain or renew their crude connections and compete successfully with the larger , more firmly established refineries . After five years or more of continuous idleness , a refinery would be rendered practically useless through corrosion and obsolescence . Consequently , most plants now being carried as " shut -down " have operated intermittently since 1923 . struction . A material change occurred in 1929 in the matter of plants under con- On January 1 , 1929 , there were 14 plants under construction , with a potential capacity of 99,000 barrels per day , whereas on January 1 , 1930 , there were only eight plants of 37,200 barrels capacity being built . This decline was due to the fact that the construction program in west Texas , which was at or near its height on January 1 , 1929 , was completed prior to January 1 , 1930 .

Apr 1, 1930

By John Ward Smith

An analytical method developed by the Bureau of Mines to determine dawsonite, nahcolite, and nondawsonite alumina (called excess alumina) extractable from Green River Formation oil shales is presented. The method requires water extraction of nahcolite followed by HCI-extraction of dawsonite and an unidentified mineral yielding excess alumina from the water-leached residue. Instrumental determination of sodium in the water extract and sodium and aluminum in the HCI extract measures the sample's content of the minerals. Detailed evaluation shows the method to be adequately specific, precise, and reproducible and free from uncorrectable interferences. The method's results define precisely the production of sodium carbonates and alumina possible from a sample of oil shale and the interval it represents. Shale-oil yields, nahcolite contents, and yields of extractable alumina determined on 83 samples representing an 821-foot section of dawsonite-nahcolite-bearing shale from .Colorado Corehole No.3, drilled in the north part of Colorado's Piceance Creek Basin, are presented. These samples resulted in nahcolite contents to 53.3 percent, oil yields to 48.3 gallons per ton, and alumina yields to 5.80 percent. Use of these data to evaluate the production potential of a section of the formation are suggested.

Jan 1, 1969

By I. D. Shah

The copper-nickel ore of the Duluth Gabbro Complex in northeastern Minnesota is a large potential domestic resource of cobalt and platinum-group metals. However, because of the low grade of the primary metal values (0.5 pct Cu, 0.15 pct Ni), the private sector has assigned a relatively low priority to the development of technology for processing this ore, anticipating that mining probably would not begin until the mid-1990's. Furthermore, preliminary processing flowsheets considered by the mining companies centered on the primary metal values. As part of an effort to help provide the basis for technology to recover critical and strategic minerals from domestic resources the Bureau of Mines is investigating methods to recover all of the mineral values, in the Duluth Gabbro material, with particular attention to the byproduct critical minerals. A key step in this process is the removal of a relatively large amount of iron present in the bulk sulfide flotation concentrate to permit subsequent extraction of mineral values. This report describes a direct smelting method that removes most of the iron and produces a copper-nickel-cobalt matte, an intermediate product from which the metal values subsequently are separated. Copper, nickel, and cobalt grade and recovery data are presented for the direct smelting method. Test results showed that under certain conditions some of the mineral values reported to the slag, requiring slag cleaning to recover them.

Jan 1, 1983

By R. E. Green

The Bureau of Mines undertook a bench-scale study of three different types of oxidized taconites3 from the Lake Superior district to improve the dispersion-selective flocculation-desliming process for beneficiating these materials. The response-surface contours of the effects of dissolved ionic species in the water and of three dispersion systems on the selective flocculation process were studied. Results of metallurgical data and chemical analyses of the aqueous phase showed that the water quality affects the performance of the selective flocculation process.

Jan 1, 1984

By N. S. Dalal, X. Shi

"Electron spin resonance (ESR) spin trapping methodology has been used to study the reactions of manganese dusts with glutathione, employing a-{4-pyridyl-1-oxide)·N-tert-butyl-nitrone (PBN) and 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as spin traps. The results show evidence for the glutathionyl radical formation in the reactions of both MnO2 and manganese (Ill) acetate with glutathione. Based on these experimental observations, we hypothesise that the mechanism of neurotoxic effects of manganese might be due to the fact that the generation of glutathionyl radicals depletes the glutathione pool and reduces the glutathione shield against free radical products of dopamine metabolism and manganese induced reactive oxygenated species. IntroductionExposure to manganese compounds often occurs as the result of foundries and mining operations (1. 2). Other significant sources of environmental manganese include coal-fired power plants and burning of residual and crude oil (3, 4). Lately gasoline combustion has also started to contribute since manganese (methyl cyclopentadienyl manganese tricarbonyl. 0. 125 g/gallon) is being used instead of lead as an antiknock ingredient in automobile fuels (5. 6). Although manganese is an essential element in certain biological processes it is toxic in excessive amounts. The manganese toxicity is mainly associated with the nervous system (7-9). Symptoms frequently observed in manganese poisoning or manganism are disorientation, memory loss, anxiety, compulsive laughing and crying, mask-like faces, akincsia rigidity and tremor (10). In spite of numerous investigations to understand the mechanism of manganese induced injury. it has not been possible to localize the initial chemical lesion responsible for altered physiology and ultimate cell death. This may perhaps he the reason for failure in developing a successful therapy for manganese intoxication."

Jan 1, 1990

The Ringelmann Smoke Chart fulfills an important need in smoke abatement work and in certain problems in the combustion of fuels. A knowledge of its history and method of preparation is, therefore, of interest to many. Since instructions on its use are not shown on the recent edition of the chart, those included in this revision of the previous Bureau of Mines publication now are a necessary complement to the chart, More detail regarding the use of the chart is included than was given in the earlier version.

Jan 1, 1967

By J. Mutmansky, C. Lee

"The size distribution of coal mine dust is one of its most important characteristics because the particle size is known to govern the region of deposition of dust within the human respiratory tract. In addition, dust characteristics, particle settling rate, transportability of the dust and the efficiency of dust control measures are all affected by the particle size. As a result, particle size distribution of the airborne dust in a coal mine is a fundamental property that impacts on the health of underground workers.This paper deals with some basic findings on the size distribution of cool mine dust based upon the results of data collection in six underground coal mines using continuous miners. All airborne dust sampling was performed on development sections using eight stage cascade impactors and permissible 2. O l / min pumps. Samplers locations were fixed in the sections with respect to the continuous miner and roofbolter or with respect to the intake and return airways • Sampling times varied from 45 minutes to 6 hours , depending upon the dust concentration. The first topic of analysis was the test to determine whether the commonly used lognonnal distribution is valid when applied to airborne coal mine dust. Secondly, the conventional method of representing the· distribution using two parameters, the geometric mean and the geometric standard deviation, is questioned. Since almost all size data were found to show some degree of bimodality, the two parameter lognonnal distribution may not represent the total airborne coal mine dust size , quite adequately. Bimodal lognonnal distribution was tested to be a good approximation in the case with two modes in the size distribution.The final topic discussed in this paper is the 'locational variation of the airborne dust size distributions within the continuous mining section. The size distributions varied considerably at the different sampling locations with the continuous miner and roofbolter producing the coarser distributions. Fine size modes in the range of 2 to 4µ m including mostly respirable dust particles were present in almost all samples • Second dust generating sources such as the shuttle car movement were found to be major causes of high respirable dust concentrations in some cases ."

Jan 1, 1988

By R. L. Grant

The conventional gallery test used by the Bureau of Mines Explosives Testing Station and corresponding establishments in other countries to establish the permissibility of explosives serves principally to differentiate the relatively safe explosive from the positively unsafe one. It has been recognized for many years that a more definitive test is needed to measure the relative incendivity to firedamp of explosives and explosive devices. A new method - the oxygen-value test - for measuring this incendivlty quantitatively has been devised and is being tested at Bruceton, Pa. To date, this testing bas been limited mainly to straight nitroglycerin dynamites. It is planned to study application of the method to permissible explosives in the near future. These results will be reported later. In the present report, permissible explosives will not be considered specifically.

Jan 1, 1954

Until man was able to produce light, his working day was pretty much limited to daylight hours. Underground miners have a special problem because in a mine it is just as dark during daytime as it is at night. The first devices used for mine lighting were torches and open flame 011 lamps. Torches made from twisted grass and dipped in tallow or pine pitch would burn for a while, but they made a lot of smoke and probably went out when they were needed most. During the 15001s, miners lamps consisted of a small metal dish with a hook attached to hang it up. The saucer-shaped dish was filled with animal or fish oil and a wick made of twisted fibers was laid In the 011 and hung over one edge where it would burn. This lamp would burn longer than a torch, but the amount of light cast by the pale, flickering flame was probably only a little better than no light at all.

Jan 1, 1976

By Liane L. M. Kadnuck

This report summarizes the results of a hydrologic research study conducted by the U.S. Bureau of Mines (USBM) in cooperation with Energy West Mining Co. at the Deer Creek and Cottonwood Mines, near Orangeville, UT. The USBM evaluated hydrologic and overburden failure data to assess the response of local ground water to underground coal mining in single-and multiple-seam conditions. Fourteen springs located over the two mines were investigated in the study along with overburden failure response caused by longwall panel extraction. Spring discharge was compared to climatic variation and time of undermining to quantify response to undermining. Spring discharge had been reduced owing to below-normal precipitation during the period evaluated. The response of springs to mining in the vicinity was influenced in part by the thick overburden present at the study site the presence of hydrophilic clays and mudstones in the overburden stratigraphy, and elevation of the springs above mine level, which buffered the effects of undermining.

Jan 1, 1994

By D. J. Parker

State governments are increasing their efforts each year toward promoting the safety of miners .. Accidents underground are being avoided and mines made safer by means of revising and adding to their mining laws , by enforcing them through mine inspection departments , and by hearty co - operation with other agencies working miners ' safety . The U. S. Bureau of Mines is glad to testify to the co -operation that it receives from State mining departments in its safety work ; reports of the field mining engineers of the Bureau bear witness almost daily to the efforts of the States toward safety in mining . * This Through the courtesy of Mr. William Ogilvie , District State Wine Inspector of District No. 2 , with headquarters at "cAlester , Oklahoma, the Bureau has been furnished with a copy of a letter sent to various mining companies of Mr. Ogilvie's district in Oklahoma, relative to safety in Oklahoma mines . letter shows both the vigorous efforts which the State of Oklahoma is making toward increased safety in mines , and the recognized value of the types of electric cap lamps approved by the U. S. Bureau of Mines as " permissible " for use in gaseous mines ; it is accordingly reproduced in part : "hen during my first inspections of several coal mines in the district I found gas , or fire- darp being given off more or less constantly from the freshly cut coal at numerous points throughout the mines , I became uneasy relative to safety conditions , and am still considering your safety from many angles , but I am more concerned about the gas given off and the coal dust produced daily, than any other factor at the present time .

Jun 1, 1922

Provide reasonably priced, reliable fire protection for front-end loaders. Approach Automatic fire sensing and suppression systems were developed and ruggedized for use on front-end loaders operating in harsh mine environments. How It Works Temperature sensors mounted in the loader's engine, transmission, and articulation areas detect the heat from a fire while it is still small and controllable. This triggers the release of the ABC class dry chemical extinguishing agent through a fixed piping system onto the fire. The system can also be manually activated from either the cab or ground level. Locations of the principal components of the system are shown in the drawing. Two control subsystems were designed to respond to varying fire protection needs and mine conditions. One subsystem only initiates discharge of the extinguishing agent. The other subsystem initiates visual and audible operator alarms if there is a fire sensed or if there is a fault in the control circuit.

Jan 1, 1979

The head loss data for coal slurries over a range of concentrations and velocities and the laboratory screen analysis were selected as areas for investigation in the data analysis performed. The analysis resulted in the following: (1) Size distributions for the coal used in the horizontal pipeline tests were fitted to the Rosin - Rammler distribution function. Each of the fits was significant. Corresponding Rosin - Rammler parameters were obtained which were introduced into the regression analysis. (2) A regression equation was obtained which predicts the slurry head loss of 1-inch by 0 coal slurries ranging in volumetric concentration from 20 to 40 percent and line velocities from 1 to 14 feet per second as a function of the square of velocity. The addition of the term for concentration in the regression equation did not contribute significantly c head loss.

Jan 1, 1972

By Hugo E. Camargo

In an effort to reduce Noise Induced Hearing Loss (NIHL) in the mining industry, the National Institute for Occupational Safety and Health (NIOSH) is conducting research to develop noise controls for mining equipment whose operators exceed the Permissible Exposure Level (PEL). The process involves three steps: 1) Noise source identification (NSI), 2) development of noise controls, and 3) evaluation of the developed noise controls. For the first and third steps, microphone phased array measurements are typically conducted and data are processed using the conventional beamforming (CB) algorithm. However, due to the size and complexity of the machines, this task is not straight forward. Furthermore, because of the low frequency range of interest, i.e., 200 Hz to 1000 Hz, results obtained using CB may show poor resolution issues which result in inaccuracy in the noise source location. To overcome this resolution issue, two alternative approaches are explored in this paper, namely the CLEAN-SC algorithm and a variarion of an adaptive beamforming algorithm known as Robust Capon Beamformer (RCB). These algorithms were used along with the CB algorithm to process data collected from a horizontal Vibrating Screen (VS) machine used in coal preparation plants. Results with the array in the overhead position showed that despite the use of a large array, i.e., 3.5-meter diameter, the acoustic maps obtained using CB showed "hot spots" that covered various components, i.e., the screen deck, the side walls, the I-beam, the eccentric mechanisms, and the electric motor. Thus, it was not possible to identify which component was the dominant contributor to the sound radiated by the machine. The acoustic maps obtained using the RCB algorithm showed smaller "hot" spots that in general covered only one or two components. Nevertheless, the most dramatic reduction in "hot" spot size was obtained using the CLEAN-SC algorithm. This algorithm yielded acoustic maps with small and well localized "hot" spots that pinpointed dominant noise sources. However, because the CLEAN-SC algorithm yields small and localized "hot" spots, extra care needs to be used when aligning the acoustic maps with the actual pictures of the machine. In conclusion, use of the RCB and the CLEAN-SC algorithms in the low frequency range of interest helped pinpoint dominant noise sources which otherwise would be very hard to identify.

Jan 1, 2009

By Thomas V. Falkie, R. Venkataramani

Table

Jan 1, 1972

By M. D. Schlesinger

Experimental data for coal hydrogenation are presented to show that when a vehicle oil produced from coal is present, coal is hydrogenated to the same high conversion whether molybdenum catalyst is impregnated on the coal or intimately mixed with the slurry. Differences in product distribution could be related to the severity of operating conditions. No minimum mixing time was established, but 2 hours was sufficient. Longer periods of mixing, to 14.75 hours, had no effect on the results. The hydrogenation conditions were in the pressure range of 8,500 to 10,000 p,s,i. at 400° to 500° C. Most of the experiments were made in duplicate. The results were obtained with molybdenum concentrations of 0.01, 0.1, and 1 percent. Al the mentioned pressure range and a time at temperature of 15 to 60 minutes, coal conversions higher than 98 percent were obtained.

Jan 1, 1962

By S. J. Schatzel, P. W. Jeran, W. P. Diamond, F. E. McCall, F. Garcia, J. C. LaScola, T. P. Mucho

The National Institute for Occupational Safety and Health, Office for Mine Safety and Health Research, is investigating the geologic and mining factors influencing the migration of longwall gob gas. One goal of these studies is to optimize methane drainage strategies to reduce the volume of gob gas that reaches the underground workplace. As part of this research effort, longwall gob gas flow paths in a mine operating in the Pittsburgh Coalbed, PA, were investigated using SF6 tracer gas. Tracer gas released into the ventilation airflow underground generally stayed in the bleeder system and was vented at the associated bleeder fan shafts. Tracer gas injected into an inactive (intaking) gob gas venthole migrated to the two inby producing ventholes on the study panel, indicating that all three ventholes were in communication. The tracer gas that was injected into the gob generally stayed in the gob and only migrated to the ventilation system in response to the venthole on the study panel closest to the injection hole going off production. Tracer gas flow velocities in the longwall gob reservoir and factors influencing the production performance of gob gas ventholes in the study area are also discussed.