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By John B. Goodman

This report presents a study of a modification of the precision laboratory carbonization-assay apparatus that renders the unit capable of performance at low-, medium-, and high-temperature assay levels and permits, under controlled conditions, evaluation of the relationship between carbonization temperature and the yield of pyrolysis products. Second, the interest and value derived from the temperature study data directly apply to the particular semiplant carbonization processes and techniques currently being investigated in this laboratory. Data obtained with the assay apparatus enables the fuel technologist to predict the probable yields of carbonization products from pilot-plant operations under various carbonizing conditions. Data obtained with the assay apparatus has been used to predict the product yields of industrial carbonization plants at Kemmerer, Wyo., and Rockdale, Tex. The assay provides a useful tool in detecting, from the carbonized plant product, the degree of effectiveness of pilot-plant operation. Third, the residual volatile matter in some industrial carbons has broad significance. Evaluation of the volatile material remaining with or in the carbon may be assessed through the high-temperature-assay technique. The low-temperature carbonization assay devised by the writers has proved to be a versatile tool in predicting the probable product yields from pilot-scale carbonization processes. The apparatus described in previous publications has been modified to extend the range of testing above 500° C. without impairing the accuracy and reproducibility obtained in the low-temperature range. Results presented here include product yields from a typical Texas lignite and Wyoming subbituminous-B-rank coal over the temperature range 150° to 1,000° C.

Jan 1, 1958

To provide a means for rapidly evaluating proposed mine layouts in order to avoid potential hazards while minimizing loss of coal. The Approach: Development of a computer program that will compute many possible mine layouts by changing the mine plan until the arrangement giving minimal hazards with optimum extraction is found. How It Works: The Hazard Evasion Program for Mine Planning, developed by the Bureau's Denver (Colo.) Mining Research Center, tests hundreds of possible solutions to a mining layout, and by sorting out the 10 best (based on the criteria of maximum safety for workers with minimum abandoned coal), limits the number of choices that need to be considered and appraised for applicability to a given mine scheme. The program is applicable for room and pillar or longwall mining, for oil and gas well hazards, and for other hazards that can be described mathematically such as channel sands, potential bad roof areas, faulting, voids, or water pockets.

Jan 1, 1974

To reduce air be respirable dust generated from emptying dry dust collectors on small truck-mounted drills used at surface coal mines.

Jan 1, 1995

By Franklin P. Hall

U.S. supply and demand data for utility electricity by States and regions were tabulated for the years 1960 and 1965. Estimates are provided of State-by-State quantitative data for the utility electricity industry that can be integrated into State and regional energy balances by source, form, and major consuming sectors, and used to determine basic flow-patterns. The difficult problem of compiling interstate and interregional shipments of electricity was resolved by (a) assuming the negligibility of interregional shipments and (b) deriving a theoretical line loss percentage used for determining interstate shipments. The data developed were able to show an estimated total supply of utility electricity available for consumption. The tables also report the distribution of the supply among the major consuming sectors (household and commercial, industrial, and transportation). To compare the various energy sources of utility electricity, quantities were converted to their British thermal unit (Btu) equivalents. The Federal Power Commission, Edison Electric Institute, and Bureau of Mines are the sources of the data used in this study.

Jan 1, 1969

By Sean Gallagher, Rhys Llewellyn, Jay Mattos

This paper contains the results of an examination of accident, injury, employment, and production information reported to the U.S. Department of Labor's Mine Safety and Health Administration (MSHA) and provides information on some of the measures longwall mine operators are using to prevent accidents In all industries, technological advances play a key role in determining those who will survive as competitive participants in an increasingly global marketplace. While mining is among the most basic of industries, technological change is neither unfamiliar nor unwelcome to miners. Historically, technological advances in mining, particularly coal mining, have tracked closely with fluctuations in demand. In the early 1900's, coal accounted for more than three quarters of all the fuel consumed in the U.S. To meet this tremendous demand, underground cuffing machines were introduced, resulting in faster, more efficient coal extraction. Transporting coal to the surface, however, remained labor intensive. In the 1920's, nearly all underground coal was still being hand loaded. Demand for coal then declined as the price of oil, natural gas, and electricity became competitive. In the late 1930's and throughout the duration of World War II, coal demand and production was high. By 1940, more than half the coal mined was being mechanically conveyed to the surface. In 1948, the continuous mining method was introduced in the U.S., further accelerating the extraction process. By the 1950's and 1960's, however, coal production again declined as railroads converted to diesel fuel and gas and oil provided a larger share of the home heating market. Underground coal mines required even more mechanization to remain competitive as an energy source. The first longwall system was introduced in 1960. By 1995, longwalls were producing more than 189 million tons of clean coal annually, surpassing continuous mining production for the second straight year. The mining of coal and other materials has not come without a huge loss of life and considerable human suffering. More than 103,000 workers died from injuries in U.S. mines in the last 85 years. Between two and three thousand miners died each year from the turn of the century until 1931, many from underground fires and explosions. The U.S. has witnessed a tremendous drop in fatalities in underground coal mines. Credit for that is due to safety inspections and enforcement activities, better safety awareness and practices among management and labor, improved ventilation, the use of safer equipment, and increased mechanization which removed many miners from the hazards at the face and also reduced the size of the mining work force. There is little doubt that longwall mining has greatly increased underground coal mine productivity. The degree to which longwall mining has contributed to a safer work environment for underground miners is more difficult to ascertain.

By J. B. Littlefield

This study is one of a number conducted to determine the concentration of dust in the air during the complete cycle of operation in wet drilling information as to various factors connected with drilling in mining operations is considered to be of definite value in the control and prevention of air dustiness, and it is particularly desirable to ascertain What features of present-day wet-drilling operations in mine work contribute to dust disease and to remedy deficiencies when they are found. ACKNOWLEDGMENTS A testing alit through rock strata is being developed by the Mining Division of the United States bureau of Mines at Mount Weather, Va., and the tests discussed in this report were conducted there. This experimental alit in rock, constitutes a typo of laboratory where mine conditions can be closely simulated and where many of the variables likely to occur in an actual mine can be eliminated or at least controlled with reasonable effort, thus affording maximum opportunities to secure fundamental data uncomplicated by extraneous conditions. The authors wish to acknowledge the valuable assistance and cooperation of several members of the Mining Division, particularly C. F. Jackson, chief engineer, McHenry Mosier, associate mining engineer, and G. E. McElroy, supervising engineer, mine ventilation.

Jan 1, 1938

By Daryl E. Radcliffe

The Bureau of Mines studied the displacement of the roof in a portion of the Bear coal mine near Somerset, Colo, Horizontal-and vertical-displacement gages were installed in a five-entry section during normal room-and-pillar mining procedures. Monitoring of the roof continued until this section was mined out. Displacement measurements in combination with known time lapses between mining and bolting operations indicate that once support is achieved, the length of unsupported time does not appear to affect long-term roof stability in the mine under investigation.

Jan 1, 1978

By Mark S. Sanders

The purpose of this work was to develop and field test improved knee protection for underground coal miners working in low seam mines. In a previous phase of this contract (Sanders, 1982), experimental knee pads were developed and field tested. The field test revealed several design deficiencies with the knee pads, and suggestions for improving the design were made. The work summarized in this report, therefore, consists of modifying the design and method of fabrication of the knee pads originally describes by Sanders (1982), and of field testing the improved design. The new prototype was shorter and wider than the original design, and used a neoprene pass-through strap design rather than a cloth strap molded into the pad itself. The new prototype was constructed by slush molding a hollow bladder that was then filled with foam. Initial reactions to the pads in the field test were very positive. However, after two months, the opinions about the new prototype became less positive. They were judged, generally, to be no better or worse than the pads usually worn by the field-test participants. Problems were encountered in the field with respect to durability. Water seeped into the inner cavity of many of the pads and caused the foam to deteriorate. It was concluded that it would not be cost-effective or feasible to significantly improve upon current commercially available knee pad designs.

Jan 1, 1986

By N. H. Coates

As part of a joint program of the U.S. Atomic Energy Commission and the Federal Bureau of Mines for using nuclear energy to supply process heat, the Bureau designed and constructed a pilot-scale simulated nuclear reactor system. Although workable components were developed,5 the simulated nuclear reactor could not be operated continuously at its design conditions of 2,500°F. and 250 p.s.i.g. because the refractory materials used for insulation deteriorated. Replacement of these materials with porous carbon permitted sustained operation at design conditions, and a 1,000-hour demonstration run was completed successfully. No serious operating difficulties developed during the test. Leakage of helium after 1,000 hours was only 3 to 4 std. c.f.h. Inspection after the run revealed no damage to any of the components. Including earlier runs during previous research5 the system has been operated about 4,000 hours, of which 1,120 hours have been at 2,500° F. or higher. The helium-recycle compressor performed satisfactorily with no main¬tenance whatever for 2,445 hours, with about 2,000 hours at 900° to 1,000° F.

Jan 1, 1961

"The town of Monson in Piscutaquis County, Maine is the, center of an important site industry. Monson slate has a nation-wide reputation, particularly for electrical switch boards, and the deposits have been worked for the manufacture of such products for many years. Open-pit quarrying is the method most commonly employed in obtaining slate. Underground methods have been used in the Peaon Bottom district near Delta, Pennsylvania, but the quarries that were thus operated are now abandoned. Underground methods have been used more extensively in foreign countries, the most famous example being the slate mines at Angers in France, where an over-head stoping method has been employed successfully for many. It is only under special conditions that underground methods can be successfully used. If the deposit is wide and relatively thin, or if the material is too unsound to constitute a safe roof, open-pit methods must be used, for slate is too low-priced a commodity to justify the heavy expense of any timbering methods. It is only where the deposit is relatively narrow, of great depth, and sufficiently sound to afford a strong roof that ordinary mining may be employed.The best slate beds in two of the three quarries operated at Monson are no worked by underground methods. The chief bed worked by the PortlandMonson Slate Co. is 10 feet thick, stands vertical and strikes N. 63º F. The slaty cleavage is vertical and crosses the strike of the beds at an angle of 5 to 10°. The grain or second direction of splitting is vertical and perpendicular to the cleavage. In addition to the 10-foot bed, to 2-foot beds and one 5-foot bed are available but are not now utilized. In theMonson Maine Slate Co. quarry (the old Pond quarry) a greater number of beds available, but at present quarrying is confined to a single bed about 9 feet thick which dips 30º S.E. and strikes N. 47ºF. The slaty cleavage is vertical and strides N. 45º F., while the grain strikes N. 45-50º W. and is also vertical."

Nov 1, 1920

By E. W. Dean

In the early winter of 1919 the Pittsburgh petroleum laboratory of the Bureau of Mines undertook the work of testing fuel oil samples representing purchases of the United State Shipping Board for ships sailing from the port of New York. fuel oil was, at this time, being bought on a contract which involved specifications issued by the United States Navy under dace of October 2, 1920 (See Bulletin 1, Oil Division, U. S. Fuel Administration.)The object of the Bureau of Mines in undertaking this inspection work was twofold. (1) The Bureau was in position to give, and the Shipping Board needed, reliable laboratory service for checking the quality of the fuel oil purchased, the value of which ran into millions of dollars for,year's supply. (2) It was believed, and later demonstrated, that the existing specifications did not insure the obtaining of a reliably satisfactory quality of oil.The objection to the specifications concerned the employment of a clause limiting the gravity of the oil. The inadequacy of gravity specifications for several types of petroleum products has long been recognized, and there was every reason to reason to believe that they were no more desirable for fuel oil than for gasoline, kerosene, or lubricating oil. A first and obvious objection was the fact that it is somewhat difficult to make accurate gravity tests on ""heavy"" residuum fuel oils. (The Bureau found it necessary to employ or such tests a rather tedious procedure involving the use of a picnometer and an accurate balance, as the simpler methods, employing hydrometer or displacement balance, proved unreliable in a large proportion of cases.) A second and more important objection was that gravity tests, even when accurately made, do not provide a reliable index of the actual quality of the oil.

Feb 1, 1921

By N. T. Lowe, R. E. Miller

When two pieces of heavy equipment interact, jolting and jarring can occur. During haulage truck loading for example, there is a chance that the operator of one or both pieces of the equipment will experience jolting and jarring. Additionally, a jolt can occur when an off highway equipment operator drives over a road defect or inadvertently strikes a berm. Aside from the operators, there is seldom anyone else that witnesses the interaction and can accurately describe the extent of the jolting. This makes it difficult for health and safety managers to address jolting and jarring. The devices and software described in this paper constitute a method for installing “black boxes” called Shox Boxes onboard equipment that already have a GPS system onboard. The resulting configuration provides an objective assessment of jolting and a chance to determine the root causes of it. The Shox Box system reviews data in real time, onboard the vehicles, 24 hrs a day, and sends pertinent information via radio to a central database. The data generated shows whether jolts are above or below a supervisor defined target value for the equipment and the tasks being performed. This allows health and safety personnel to demonstrate safe operation of heavy equipment and recommend proactive actions to maintain jolting within a reasonable range.

By Raymond B. Ladoo

The Bureau of Mines frequently receives requests for information on the mining , preparation and marketing of epsomite or Epsom salt , and in order to answer such inquiries the following information has been compiled . While it is probable that few people have considered epsonate as a mineral product , it will be noted that it should be so regarded and its production forms an important industry .

Mar 1, 1922

By Rudolf Kudlich

"During the coming winter, it is probable that many householders who have habitually been users of anthracite coal will be obliged to turn to some other fuel for heating purposes, because of the limited supply of anthracite. The next best fuel, from a standpoint of cleanliness and ease of operation, is coke, but here again the supply is inadequate and the householder will have to fall back on bituminous coal. Though bituminous coal has the dis¬advantage of being dirty to handle, requiring more care in firing, and of giving off considerable smoke, it will be more generally available, costs less, and in the better grades which will naturally find their way to the domestic market, is higher in heat value, and contains less ash than anthracite.Choice of CoalThere a variety of bituminous coals are available, the householder should choose a low volatile coal, such as New River, Pocahontas, or some other ""smokeless"" coal, or the British coal now being offered in the markets along the Atlantic seaboard. Though not necessary to have the coal sized, as is the case with anthracite, it will be found cleaner to use coal from which the fine dirt has been screened. If it is found that excessive dust is caused when firing the coal, this can be reduced by slightly wetting the coal at the front of the bin, as it is being used.Method of Firingusing bituminous coal instead of anthracite in the domestic furnace, it will be necessary to use an entirely different method of fir Instead of leveling the fuel bed and putting on fresh coal in an even layer over the entire fire box, the coked and partly burned coal remaining from the previous firing should be pushed as much as possible to one side of the box, and the fresh coal thrown into the empty side so as to leave some burning coal exposed. In this way the green coal is heated slowly, the volatile gases are given off gradually, and are ignited by the burninggoing to waste up the chimney unburned."

Oct 1, 1922

GLOSSARY TERM DEFINITION ACCOMODATION The process by-which the eye changes focus from one distance to another. ADAPTATION The process by which the retina adjusts-to more or less light then it was exposed to during an immediately preceding period. Also involved, to a lesser degress, is the change in the size of the pupil which regulates the amount of light entering the eye. Adaptation results in a change in the sensitivity of the eye to light. CENTRAL VISION (FOVEAL) The seeing of objects in the central or foveal part of the visual field. It is approximately two degrees in diameter and permits seeing much finer detail than does peripheral vision. DIRECT GLARE The effect of brightness or brightness differences within the visual field sufficiently high to cause annoyance, discomfort, or loss in visual performance. FOOT CANDLE A measure of the amount of light falling onto a surface. FOOT LAMBERT A measure of the amount of light that is being reflected by a surface. GLARE The effect of brightness or differences in brightness within the visual field sufficiently high to cause annoyance, discomfort, or loss in visual performance. LAMP A generic term for a man-made source of light. By extension, the term is also used to denote sources that radiate in regions of spectrom adjacent to the visible.

Jan 1, 1976

By Marc T. Filigenzi

Two of the major ground control safety issues confronting underground mine operations today are shaft pillar stability and the failure of rock around active mine openings. Failure of a mine shaft can lead to the entrapment of workers. Failure of rock around active underground mine openings can lead to roof falls, which in turn can result in worker injuries and fatalities. Finite-element analysis has proven to be a reliable method for predicting stresses and displacements around underground mine openings. However, this is a complex and time-consuming technique and is not used as often as it could be in mine planning. The purpose of this paper is to demonstrate one technique developed at the Spokane Research Center that allows the user to create a finite-element model of a two-dimensional section of an underground mine in a relatively straightforward manner. This model is then used to calculate stresses, displacements, and safety factors around mine openings. With this information, mine planers can evaluate the stability of mine openings as well as the stability of pillars and mine shafts. This analysis will help develop mining sequences and layouts that minimize stresses in that section of the mine. This, in turn, should minimize the occurrence of shaft failure, roof falls, and other hazards associated with underground mining.

By J. B. Littlefield

This study is one of at number conducted to determine the concentration of dust in the air during the complete cycle of operation in wet drilling; information as to various factors connected with, drilling in mining operations is considered to be of definite value in the control and prevention of air dustiness, and it in particularly desirable to ascertain whet features of present-day wet-drilling operations in mine work contribute to dust disease and to remedy deficiencies when they are found.

Jan 1, 1938

By Dean H. Ambrose

This paper presents an approach for representing and analyzing random motions and hazardous events in a simulated three-dimensional workplace, providing designers and analysts with a new technique for evaluating operator-machine interaction hazards in virtual environments. Technical data in this paper is based upon a project striving to reduce workers' risks from being hit by underground mining machinery in a confined space. The project's methodology includes human factors design considerations, ergonomic modeling and simulation tools, laboratory validation, and collaboration with a mining equipment manufacturer. Hazardous conditions can be analyzed in virtual environments using collision detection. By simulating an operator's random behavior and machine's appendage velocity, researchers can accurately identify hazards, and use that information to form safe design parameters for mining equipment. Analysts must be discerning with the model and not read more from the databases than what the simulation model was designed to deliver. Simulations provided an interesting approach to data gathering in that there was no need for live subjects and logistics - test sites and costs associated with experiments-became insignificant. Collisions versus speed, operators' size, and risk behaviors proved the versatility found in the data obtained from the model. Preliminary results show that response time significantly affects the number of collisions experienced by the virtual subject. Also simulation data suggests that more mishaps occur with hand-on-boom-arm risk behavior.

Provide the mining industry with a wireless surveying system for increasing efficiency in the drilling of methane drainage or exploration boreholes. Approach The Bureau of Mines has pioneered the technique of methane control by drilling long, horizontal drainage holes from within the mine complex. It was recognized during the early drainage projects that a major portion of the drilling operation was dedicated to hole surveying. In some cases more time was actually being spent on the surveying operation than on drilling. The large amount of time required for hole surveying was the result of having to pump an instrument to the bottom of the hole, then retrieve it with an attached wire line. Naturally as hole depth increased, so did the amount of time needed to perform the survey operation. If the survey operation could be improved it was obvious that overall efficiency in drilling of long, horizontal methane drainage holes would be greatly increased. The Bureau of Mines, therefore, developed, fabricated and tested in an operating coal mine a permissible wireless survey system specifically designed for small diameter methane drainage drilling. The prototype survey system was completed in 1982 and was given the IR-100 Award by Industrial Research and Development Magazine. A second generation survey system is currently being constructed using updated state-of-the-art electronic technology. The second generation system will be more portable, more reliable, easier to maintain, and less costly.

Jan 1, 1984

By Fred N. Kissell, Jon C. Volkwein

In This Chapter [How inert gas works to prevent methane explosions How inert gas is generated and delivered at highwall mines Volume and quality requirements for inert gas at highwall mines How an inert gas system is operated and Precautions to take during mining to prevent methane explosions] This chapter discusses a method, originally developed by Volkwein and Ulery [1993], to prevent methane explosions during highwall mining. In highwall mining, a horizontal auger or a mining machine enters the coal seam from a surface mine pit at the bottom of a highwall, and the coal is mined out from a series of parallel holes. Explosions can be prevented by injecting inert gas into each hole as it is mined. Coal near the surface has lost most of its methane gas over time. However, in recent years, surface mining has been used for deeper reserves of coal. This trend toward mining deeper reserves has increased the chance of encountering methane, and methane explosions at highwall mining operations have resulted in injuries. HOW INERT GAS WORKS TO PREVENT METHANE EXPLOSIONS A methane explosion requires the presence of sufficient amounts of both methane and oxygen, as well as an ignition source. If the methane cannot be reduced and the ignition source cannot be eliminated, then explosions may be prevented by adding an inert gas, which contains little to no oxygen, to the mixture [FWQA 1970]. Just how much inert gas must be added depends on the mining rate, as well as the composition of the inert gas. An explosibility diagram can be used to show whether a methane mixture is explosive after inert gas is added [Zabetakis et al. 1959] (Figure 10–1). This diagram indicates that gas mixtures fall into one of three range categories—explosive, explosive when mixed with air, and nonexplosive—depending on the percentage of methane and percentage of “effective inert.” Effective inert is calculated from the percentage of “excess nitrogen”3 and percentage of carbon dioxide in the mixture.

Jan 6, 2006