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By H. E. Thomas

[The Bureau of Mines has conducted a field hydraulic fracturing experiment to determine the preferential orientation of induced fractures in oil shale at a depth of about 400 feet in the Green River Basin of Wyoming. The hydraulic fracturing treatment was performed by injecting extremely viscous water-base gel and 8- to 12-mesh sand into the oil shale through straddle packers set in an impermeable section of smooth-walled, 6-1/4-inch-diameter open hole. An impression packer proved that a horizontal fracture, which has an average width of about 1/2 inch at the borehole, was induced. A corehole drilled 100 feet from the fractured well intersected the fracture and confirmed its horizontal orientation. Because a horizontal fracture was successfully initi¬ated, it is inferred that the creation of multiple, closely spaced horizontal fractures may be feasible in Green River Basin oil shale.]

Jan 1, 1972

The Leuna Factory of the I. G. Farbenindustrie A. G., situated near Merseburg, is the biggest heavy-chemical plant in Germany and produces a very wide range of products, mainly based on hydrogen or hydrogen and carbon monoxide. Its principal products are ammonia, synthetic petrol derived from the hydrogenation of brown coal, and synthetic alcohols made from hydrogen and carbon monoxide. The plant was first, visited on April 21, 1945, by a team including E. Cotton, V. Haensel, E. B. Peck, P. K. Kuhne, H. M. Weir, L. L. Hirst, W. W. Odell, G. U. Hopton, H. Hollings, J. F. Ellis, and H. G. Simpson. It was again visited on May 8-24, 1945, by a combined British and American team consisting of R, Holroyd, M. A. G, Banks, D. A. Howes, A. J. V. Underwood, R. A. Taylor, W. F. Faragher, H. Schindler, and J. G. Allen. This team was later joined by J. F. Ellis and R. J. Morley. A third visit with particular reference to catalyst manufacture was made by W. F. Faragher and W. A. Horne, and the notes of these latest investigators have been taken into account in preparing the report. This report was edited by Dr. R. Holroyd.

Jan 1, 1946

By William G. Hedling

The operation of electric face equipment in underground coal mines has proven to be extremely hazardous to mining personnel, including equipment operators and others working in the vicinity of active equipment. Recent industrial engineering studies* of accidents and fatalities indicate that a major contributor to this hazardous situation is noncompliance with modern principles of human engineering, particularly lack of standardization of control configurations. Control configurations differ not only among different machine types, but also among the same machine types produced by different manufacturers. This lack of standardization can produce a high incidence of error in the operation of electric face equipment, thus creating a potential source of accidents. Other examples of non-compliance with human engineering principles are the widespread use of identical black, round control knobs (regardless of the function being performed), and the inappropriate location, spacing, and labeling of controls. Any or all of these factors may place the operator in a "negative transfer" situation, which means that control manipulations appropriate for one type of machine are different from (or even the reverse of) the control movements required to produce the same effect on other machine types. This situation increases the accident potential to the operator, as well as to others in the vicinity. Accident potential is further increased by circumstances which do not allow for large error tolerance-specifically, emergency procedures. Reports of accident statistics cite operator inexperience as a primary cause of most accidents involving underground electric face equipment. Several factors contribute to operator inexperience, including: 1. High personnel turnover 2. Employee absenteeism 3. Current union practice of bidding for jobs.

Jan 1, 1974

By Keith L. Harris

The performance of the world economy improved significantly in 1984. Real world output!/ grew 4.3% (compared with 2.6% in 19831, the highest since the 4.4% increase recorded in 1978 (table 1). The output of industrial nations rose 4.9%, while that of the developing nations rose 3.7%. The United States and Japan had the largest increases in output of the major industrial nations, with respective increases of 6.8% and 5.8% (table 2). The components of real output with the most significant growth in the industrial countries were gross fixed investment (9.2%), consumer expenditure (3.1%), and public consumption (2.5%) (table 1). Industrial output, as measured by industrial production indices, has returned to about the 1980 level for most of the major industrial nations (table 2). Exceptions to this were industrial production in Japan and the United States; Japan's industrial production rose steadily throughout the 5-yr period and is now more than 16% above the 1980 level, and the industrial production index for the United States reached 11 1.2 (1980=100.0). Real total domestic demand grew at 8.7% in the United States, more than double the rate of Japan, which, at 4.0%, had the second-largest growth. Average demand for all industrial countries was up 5.1%. During 1984 the U.S. dollar showed great strength on international markets, contributing to large current-dollar negative net exports of goods and services and even larger negative net exports of the merchandise sector. While growing U.S. imports helped spread the benefits of the recovery, they also led to a widening of current account imbalances and growing trade tensions throughout the world.3/, 4/

Jan 1, 1985

By James C. Patterson

Sintered fly ash was shown to have promise as a modifier for poorly drained soils. Turf grown in mixtures of sintered fly ash and soil benefited from increased water-infiltration rates, greater total pore space, and higher moisture availability, The result was an improved turf stand with increased grass yield and root density.

Jan 1, 1970

By Fredrick M. Ryan

Present indications are that in about 2-3 years phosphor tags will be required in commercial explosives. A permissible 254 run ultraviolet lamp assembly has been developed to permit mine inspectors to detect such phosphor tags and therefore to establish if non-permissible explosives were used. This new lamp is powered by a Miner's cap battery without interference with the normal lighting requirements of the cap lamp battery. It is compact, light, and rugged with very high ultraviolet output.

Jan 1, 1977

By Fred S. Karn

Inhibitors are used in coal mines as a precaution against accidental dust explosions. Although rock dust is the usual inhibitor many others have been tested. To facilitate testing a screening process using laser irradiation was proposed. The procedure includes irradiation of a coal-dust mixture followed by mass-spectrometric analysis of the evolved gases and an evaluation of the flammability characteristics of the gases. Carbonate-type inhibitors decreased the percentage of combustibles in the gases generated and inhibitors like NaCI (thermally stable salts) decreased the total gas generated. A suitable test procedure did not result from the investigation, demonstrating the inadequacy of fast heating, non-combustive techniques in rating inhibitors of coal dust explosions.

Jan 1, 1973

By J. E. Rourke, O&apos

This report incorporates a review of available dewatering technology and an evaluation of its relevance to surface coal mines in the Interior Province of the United States. Guidelines for the selection, design and construction of dewatering systems are included. On the basis of documented experience, candidate dewatering systems were selected and evaluated with respect to their anticipated impact on the environment and mine operations. Included in the discussion is a summary of laws and regulations which can impact on dewatering operations. Following this discussion, geologic and hydrogeologic conditions within the Interior Province are described and potential dewatering problems at surface coal mines are identified. Model mines are developed which exhibit the most difficult dewatering problems identified, and it is demonstrated how available technology can be utilized to deal with these problems. Dewatering of coarse-grained, high permeability terrace deposits might be economically feasible today. Low permeability, saturated glacial tills or lake deposits appear to be significantly outside present economic feasibility for dewatering.

Jan 1, 1979

By Frank E. Cash

As a part of its safety program the United States Bureau of Mines has fostered the development, use, and improvement of portable electric mine lamps. Although there is still need for better illumination in mines and the replacement of open lights has been slow, improvement in electric cap lamps and increase in their use indicate one phase of recent progress toward safer and more efficient mining This report is the result of a recent survey of electric-lamp installations in the Alabama mining; district; it shows the misuse, increase in use, and relation to certain classes of accidents of these installations.

Jan 1, 1935

By Linneas W. Laage

The purpose of this report is to document the fire experiments conducted at the Waldo Mine, NM during March 1990. The U.S. Bureau of Mines is concerned with improving and validating the predictive capability of the mine ventilation and fire simulator, MFJRE. To accomplish this, fire experiments were conducted at the Waldo Mine and temperature profiles were developed as functions of time and distance from the fire. These tests then provided data for verifying the heat transfer model in the MFIRE mine ventilation and fire simulator. An initial analysis of this data indicates that it will serve this purpose well. This report summarizes the data obtained during six fire tests at the Waldo Mine.

Jan 1, 1994

By Thomas M. Barczak

The 1990s brought an unprecedented increase in the development of innovative technologies to provide more effective and easier-to-install roof support in underground mines. To facilitate the application of these technologies in improving mine safety, the National Institute for Occupational Safety and Health (NIOSH) developed the Support Technology Optimization Program (STOP). STOP is a Windows-based software program that provides mine operators with a simple and practical tool to make engineering decisions about the selection and placement of these various roof support technologies. The program includes a complete database of the support characteristics and loading profiles obtained through safety performance testing of these supports at the NIOSH Safety Structures Testing Laboratory. A support design criterion in the form of the required support load density at a specified convergence can be established from four options: (1) a database of measured ground reaction obtained from various mines or ground behavior information input by the user,(2) load requirements based on a detached roof block or rock failure height, (3) criteria based on the current roof support system, and/or (4) arbitrary criteria set by the user. Using these design criteria, the program will determine the installation requirements for a particular support technology that will provide the necessary support load density and convergence control. Optimization routines are also available to determine the most efficient support design for a user-specified support installation. In addition to these performance measures, STOP can be used to compare material handling requirements and installation costs. Comparisons among the various support technologies are easily made, including a graphical analysis of relevant support parameters. This paper describes STOP and its application to optimizing standing secondary roof support systems.

Jan 10, 2000

By Robert L. Lagace

An investigation is made of the feasibility of developing compact transmit antennas and/or other means to efficiently couple VLF to MF band radio energy between portable wireless communication units in coal minus. The completely wireless communication ranges between two portable radios equipped with practically-sized reference loop antennas in representative coal mine environments are estimated. Antenna technology is assessed with respect to transmit moment, range, intrinsic safety, battery and wearability requirements to determine the most suitable antenna types for use by miners. It is concluded that air-core bandolier loop antennas, and perhaps ferrite-loaded loop antennas, having peak transmit moments of about 2.5 ampere-m2 will be the most effective antenna choices for portable units. This choice, however, will not allow the range goal of 1350 feet to he attained in mines having unfavorable signal attenuation and noise environments. Rectangular air-core loops are compared with grounded horizontal-wire and vertical-wire mode exciters for fixed station applications. The potential for significantly increasing the wireless communication range by inductively coupling to communications and power lines in a mine is evaluated and found to be considerable based on theoretical coupling equations. Lastly, the theoretical performance of a hybrid noise cancelling diversity receiving technique that utilizes both the electric and magnetic field components of the ambient noise to improve the receiver output signal-to-noise ratio under certain adverse conditions is estimated and shown to be favorable when the magnetic and electric field noise components are highly correlated.

Jan 1, 1977

By James P. Ulery

In This Chapter [Geologic features associated with anomalous methane emissions Gas outbursts and blowers Methane drainage strategies for mitigating anomalous methane emissions and General considerations for a methane drainage program] This chapter summarizes how certain geologic features may be associated with unexpected increases in gas emissions during coal mining. These unexpected emissions have the potential to create explosive conditions in the underground workplace. Also discussed are the generally used practices to alleviate potential hazards caused by gas emissions associated with these geologic features. INTRODUCTION Unforeseen mine gas emissions in quantities sufficient to create hazardous conditions have been attributed to sources outside the mined coalbed since the first documentation of methane explosions in coal mines [Payman and Statham 1930]. Geologic features such as faults have long been recognized as conduits for gas flow from strata adjacent to mined coalbeds [Moss 1927; Payman and Statham 1930]. Other features such as sandstone paleochannels, clay veins, and localized folding have also been recognized for their impact on gas emissions into mine work-ings [Darton 1915; Price and Headlee 1943; McCulloch et al. 1975; Ulery and Molinda 1984]. The fact that strata adjacent to mined coalbeds can emit large quantities of methane gas into mine workings is not surprising from a theoretical perspective. Many researchers have recognized that during the burial and diagenesis of the organic matter forming today’s minable coalbeds, similar dispersed organic matter in adjacent strata has produced methane in quantities far exceeding the storage capacity of the coal and surrounding rock [Juntgen and Klein 1975]. It is not surprising then that large quantities of methane can remain trapped in these strata. A potential hazard occurs when mining of a nearby coalbed causes pressure differentials and mining-induced fractures conducive to gas flow into the mine workings from these strata. This gas flow may be facilitated or temporarily impeded by the presence of geologic structures or anomalies.

Jan 6, 2006

By C. B. Davison

One goal of the Bureau of Mines is to conserve the Nation's mineral resources by developing improved performance materials. Consistent with this goal, the Bureau conducted studies on the formation of undesirable cristobalite in seven different fire clays used as refractories. The studies employed scanning electron micrography, chemical and X-ray analyses, and pyrometric cone equivalent determinations to examine the sample clays and determine the effect of thermal history and stablilizing additives on the amount of cristobalite in various calcines. This research has indicated that as fire clay calcining temperatures increased from 1390° to 1,490° C there was a gradual decrease in the percent of cristobalite present in the calcines and a progressive development of mullite crystallization. No cristobalite was found in fire clays calcined above 1,550° C, but cristobalite reappeared when the calcines were reheated to temperatures between 1,400° and 1,500° C. The research also revealed that additions of lithium fluoride (LiF) prevented formation of cristobalite in fire clay calcines.

Jan 1, 1979

By Loren R. Anderson

This is an Appendix of Volume I. In contains the results of the electric cone penetrometer soundings from the second phase of the testing program.

Jan 1, 1982

By Thomas W. Camm

This study was done to evaluate the costs of various dumping operations at waste and spoil piles. It has been theorized that accidents associated with dumping operations might be reduced by short-dumping rather than edge-dumping, but many operators have been reluctant to use short-dumping because they believe it is not as cost effective as edge-dumping. To evaluate this perception, researchers at the Spokane Research Laboratory of the National Institute for Occupational Safety and Health reviewed the costs of various dumping methods at waste and spoil piles. The study found that overall cost differences between the two methods were not significant in most cases. However, while overall cost differences between the two methods appear small, capital costs could be more significant when short-dumping if numerous dump sites are used concurrently. The choice of which method to use should be based on considerations of the safety of dozer and truck operators.

Jan 1, 2000

By Terry R. Neumann

The Olallie RARE II study area has volcanic cinder deposits with a sow potential for development. No mining claims or prospects are known within the study area, and except for common construction materials such as volcanic cinders and stone, no mineral deposits were identified. An evaluation of the geology indicates that metallic mineral deposits are unlikely to exist. No significant metallic concentrations were reported in samples from the area. The only resources in the study area are about 30 million cu yds (23 million cu m) of cinders in three cones. The cinder deposits in the study area cannot compete economically with enormous deposits of similar material in more accesible areas closer to markets. At the present rate of consumption, resources outside the area are adequate far into the future. The geothermal potential of the study area is being evaluated by the U.S. Geological Survey.

Jan 1, 1983

By Rimas Pakalnis, Doug Milne, Marc Ruest, Lewis Martin

Whereas many researchers and mine engineers have conducted tests on cable bolts using various grouts, water: cement ratios, and physical modifications of the cable to determine the load-carrying characteristics ofa bolt, few studies have been conducted on cable bolts fitted with internal instruments. Those studies that have been done have concentrated on cable response averaged over significant (6.1 m) cable lengths. Researchers at the Spokane Research Laboratory (SRL) of the National Institute for Occupational Safety and Health in Spokane, WA, are investigating the physical properties of cable bolts by replacing the conventional king wire with a modified king wire on which strain gauges have been installed. A numerical analysis was performed to match laboratory results. Loads calculated by the model were then compared to loads measured in the laboratory on 1.83-m-long cables grouted into two 0.91-m-long pull-tube assemblies. Load along the cable was monitored with 20 strain gauges installed along the length of the cable. This paper documents test results on these modified cable bolts. The instrumented cable bolt provided reproducible point measurements of cable load as opposed to load measurements averaged over long cable lengths. Such point measurements can assist in interpreting the influence of cable confinement, grout quality, rock mass stiffness, and other factors. The instrumented cable bolt is a practical field and research tool because it can predict point loading along the cable. The instrument has been successfully field tested at FMC's Granger Mine, Granger, WY; the Meikle Mine, Carlin, NV; the Stillwater Mine, Nye, MT; and the Getchell Mine, Golconda, NV. By monitoring load and displacement of the rock mass using these instrumented bolts, more-effective ground support can be selected and installed, which will lead to safer working conditions for miners.

Jan 4, 2004

By D. Harrington

"Up to the last 10 or 15 years, responsibility for accidents in mines was generally, though not universally, placed upon the person or persons immediately involved. Present-day thought is rapidly veering toward holding the industry responsible for accidents, with ultimate payment of the bill by the consumer, if financial expenditure should be necessary. While it is undoubtedly correct in principle that responsibility for accidents in and around mines should be shouldered by the employer and while it is probable that as time passes the burden will become even more definitely than now that of the mining companies, on the other hand it is an undeniable fact that large numbers of accidents occur through acts of omission or of commission of some person, very frequently the victim of the accident being the offender.Out of about 3,000 persons killed every rear in our -mines and quarries, nearly half or approximately 1,500 of the fatalities are due to falls of overlying material or of persons, about 500 to haulage, about 350 to fires and explosions, about 125 to explosives, approximately the same number to electricity, and about 300 to various miscellaneous accidents.Generally the accidents from falls involve but one or two persons at a time, and the tendency is now as it always has been to charge the victim or possibly a coworker with the responsibility. Usually this sort of accident occurs at or near a working face (statistics indicate that about 80 per cent of fatalities from falls of roof or rib occur near the face), and as it is Generally agreed that it is the duty of the worker to keep his working place safe, the worker and especially the face worker is given the blame in case of accident."

Apr 1, 1930

By George D. Dub

The Bureau of Mines, in connection with the investigations of war minerals it conducted, examined the graphite deposits of this country, studied the methods of mining and preparation used, and sought to devise more efficient methods for the preparation of domestic graphite, and to standardize the quality of the product. The graphite investigations covered three general phases, as follows: 1. An examination of the deposits in Alabama and other States, and a survey of the methods of mining and preparation used. In this connection methods of sampling and analysis were noted and experiments made to determine a standard method of sampling and a, rapid but accurate method of analysis. 2. Experimental work on the concentration and refining of domestic crucible graphite to improve the quality of the product and to lessen waste. 3. Experimental work in crucible manufacture to determine the properties of domestic flake and the maximum proportions that might be used without impairing the quality of the crucibles. This work was accompanied by photomicrographic study of crucible structure.

Jan 1, 1920