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By Ernest W. Hilton

The purpose of this investigation was to assess the environmental impact of the surface mining methods currently used in the steep-sloped areas of Central Appalachia: southern West Virginia, eastern Kentucky, southwestern Virginia and northeastern Tennessee. Comparisons are made between mountaintop/cross ridge mining, contour strip, augering and an innovative method surface shortwall mining which was attempted at Julian, West Virginia. Included in this final report are a discussion and analysis of current Appalachian production, reserves, and the extent of land affected on a county- by-county basis. Additionally, the seams within the steep sloped region have been assessed according to minimal standards of thickness, surrounding lithology, and areal extent to determine their amenability to surface shortwall mining. These seams have been tabulated with their ash, sulfur, and BTU content on a county-by county basis. Only minimal statements are made concerning quantity because of the narrow set of conditions required by the shortwall method. Other sections deal with the possible technical failings of an operational surface shortwall system based on field studies at shortwall operations, discussions with people experienced with shortwalls and research into ground control problems at sites where short- and longwall operations have been monitored. A final section details proposed additional research directions which the Bureau might take in the future.

Jan 1, 1979

By Dennis McLaughin

This report contains a description of the contract activities performed by ENSCO, Inc. under contract No. H0178069. The purpose of this project was to enhance the Bureau of Mine?s Cableless Electronic Survey System use to aid in the drilling of long (approx. 2000 feet) boreholes in coal. This drilling is performed as part of the methane drainage program. The system that was ultimately developed was field tested 2nd demonstrated in actual in-mine drilling activities. The significance of this system as compared to previous drill survey systems is the fact that it surveys without having to be inserted and removed for each survey point. It is so designed that it can withstand the shock and vibration experience by the drill string during drilling. This means an increased productivity is now possible in that drill operators can determine drill bit positioning in a near real-time environment.

Jan 1, 1981

By Gerald V. Gibbs

Quadratic functions, Q(hkl), are given to six places in increments of 0.01° for 2? from 0° to 90° for CuKa and from 25° to 180° for CuKa1. The wavelengths used for Cu in the computation are those agreed upon by the Editorial Commission of the International Tables for X-ray Crystallography (1950): CuKal 1.54051 A.; CuKa2 1.54433 A. INTRODUCTION At the Federal Bureau of Mines laboratory, Norris, Tenn., X-ray diffraction crystallography using tubes with copper targets revealed a need for a handy reference for the quadratic functions of copper radiation. The tables presented here were prepared to satisfy that need. The quadratic form Q(hkl) may be expressed in terms of the Bragg diffraction angle 2? and of the wavelength ? as

Jan 1, 1961

By R. A. Meister

The study on improving surface coat refuse disposal site inspections included surface inspections of 15 refuse disposal sites. Monthly aerial photos were taken of the sites and computer methods were used to determine elevation changes. Photogrammetric techniques that were used are described in detail. A comparison of the results of each of these inspection techniques is included. A detailed evaluation of the photogrammetric techniques was made and conclusions were drawn concerning the advantages and disadvantages of using aerial photography and photogrammetry as part of the inspection procedure. Operators' opinions of the aerial photography methods are included.

Jan 1, 1980

By J. D. Davis

THIS REPORT gives results of an investi¬gation of the carbonizing properties of coals from Pittsburgh bed, Jamison No. 9 mine, Marion County, W. Va., and from Upper Freeport bed, Bull Run No. 1 mine, Preston County, W. Va. The study included Bureau of Mines-American Gas Association tests at 800° and 900° C. and various chemical and physical tests designed to evaluate the plastic, expanding, and agglutinating properties of coal. A blend of each coal was carbonized in the 500-pound slot oven. The carbonization sample of Pittsburgh coal contained 2.7 percent moisture, 35.8 percent volatile matter, 54.4 percent fixed carbon, 7.1 percent ash, and 0.9 percent sulfur. It contained 60.9 percent fixed carbon on the dry, mineral-matter-free basis and had a heating value of 14,780 B. t. u. per pound on the moist, mineral-matter-free basis. It therefore ranks as high-volatile A bituminous and was blended with low-volatile Pocahontas No. 3 coal. Upper Freeport coal contained 2.8 percent moisture, 27.7 percent volatile matter, 60.9 percent fixed carbon, 8.6 percent ash, and 1.0 percent sulfur, as carbonized. It contained 69.5 percent fixed carbon on the dry, mineral-matter-free basis and therefore ranks as medium-volatile bituminous. It was blended with high-volatile A Pittsburgh coal from Allegheny County Pa.

Jan 1, 1952

By A. George Stern

[In the examination of bentonitic clay suspensions used for oil-well drilling fluids3/ (and for other purposes, such as a core binder for foundry sand) it is important to have comparative tests for evaluating them. A satisfactory clay for these and other purposes should have the property of forming what is commonly called a "gel," but the measurement of this property has been a real problem. To date the solution has not been satisfactory, and some of the difficulties are considered in, this, paper, which describes a simple form of instrument (identified as an eykometer) for measuring the yield point under hydrostatic conditions of non-Newtonian clay suspensions, including those muds that are thixotropic. An oil-well drilling mud serves several functions, many of which depend on the "gel" characteristics of the mud. Among the more important functions are: (a) To plaster the sides of the hole to prevent caving of the walls; (b) to prevent the loss of the circulating fluid out of the hole by seepage; (c) to carry sand and cuttings out of the hole to the surface as they are formed by the rotary drill; and (d) when circulation of the fluid stops for shut-down or other unavoidable cause, to hold the cuttings in suspension by the setting up of the gel, thereby avoiding the difficulties that result when these cuttings are allowed to fall through the fluid and pack at the bottom of the hole.]

Jan 1, 1940

By David Oyler, Craig Compton

The The National Institute for Occupational Safety and Health (NIOSH) Pittsburgh Research Laboratory (PRL) is continuing to investigate the behavior of fully grouted roof bolts in the weak roof rock of the Safety Research Coal Mine (SRCM). This paper describes the results of three studies: • A series of 24 pull tests of bolts installed fully grouted and overcored to leave 12 inches of grouted bolt. The tests compared the pull-out performance of offset-head roof bolts with that of standard 5/8-inch bolts; • A second series of 24 tests that compared the pull-out loads obtained by bolts installed with 1 ft of resin (a Short Encapsulation Pull Test or SEPT) to that of fully grouted bolts overcored to leave only 12 inches of grouted bolt, and; • An investigation into the pressures generated during the installation of fully grouted resin bolts. All of the bolts installed and pulled were overcored and removed from the roof after the pull tests to allow inspection of the resin. The first study found that there was no significant difference in pullout load between the offset-head bolts and the standard bolts. The second study, comparing the SEPT bolts and the partially-overcored fully grouted bolts, indicated that SEPT can significantly underestimate bolt anchorage grip factor, suggesting that the SEPT is a conservative measure of actual bolt performance. Significant loss of resin to cracks in the roof was observed in the bolts overcored in the SRCM. The third study explored one possible explanation for the resin loss, high pressures generated during bolt installation. These tests employed bolts installed in strain gauged steel tubes. The results confirmed that significant pressures (greater than 4,000 psi) can be generated during bolt installation. The results of the pressure tests, combined with the observations of resin loss in bolts installed in the SRCM, suggest that under some circumstances resin loss and under-encapsulation could take place and lead to degraded bolt performance. Glove fingering was observed in all recovered bolts to various degrees. The limited comparative data suggested that the effect of glove fingering ranged from slight to moderate. Complete mixing of the resin was observed on all of the 40 bolts recovered (28 fully grouted and 12 SEPT). Australian and U.S. resins were compared and the Australian resins were observed to have much smaller catalyst compartment areas and lower resin viscosities. These differences are suggested as potential explanations for occasional resin mixing problems noted in Australian resin bolt installations.

By W. G. Diamond

Lightweight aggregates have become increasingly important to the construction industry. From 1953 to 1960, the quantity of the aggregates used in concrete block, precast and prestressed concrete, and monolithic structures increased about 92 percent. The present study was conducted in Bureau of Mines Area IV which encompasses the South-Central States of Arkansas, Kansas, Louisiana, Mississippi, Missouri, Oklahoma, and Texas. This is an administrative area and does not delimit a market area or imply an economic unit. Because of the increasing importance of metropolitan areas in evaluating economic growth, significant data showing relationships between growth of the metropolitan areas and the lightweight aggregate industry are included.

Jan 1, 1964

This appendix contains the list of equipment selected for the capitol cost estimate, with the respective quotations from their vendors/manufacturers. A vendor response report along with a separate equipment and motor list has been included in the first part of this appendix.

Jan 1, 1979

By J. B. Carman

This paper, describing the concentrator of the Molybdenum Corporation of America in Taos County, northern New Mexico. 7 miles east of Questa, is one of a series on milling methods being prepared for and published by the United States Bureau of Mines. The mine from which the ore comes is 1 1/4 miles from the mill, and produces about 40 tons of ore per day by the cut-and-fill method.3 The ore contains about 5 per cent of MoS2. The mill has a capacity of 50 tons of ore per day and utilizes flotation methods. Water is taken from Red River. Power is generated by a water wheel, or by a Diesel engine in times of water shortage during the winter. The mill is located close to the bottom of a canyon, in order to obtain maximum head or, the water wheel, and the flow of ore is therefore maintained partly by gravity and partly by an elevator and pumps. ORE TREATED The MoS2 content of the concentrator feed ranges from 4.5 to 7.5 biotite, fluorite, small amounts of rhodochrosite and calcite, and the minerals of the granodiorite country rock.

Jan 1, 1932

By G. S. Beaumont

This report presents a programme of work to demonstrate the use of a surface-based centralised computer control system for the remote monitoring and control of underground conveyors in a US coal mine. The system selected for demonstration was the 'Dynalink' Micro MINOS system which is manufactured by Hawker Siddeley Dynamics Engineering Limited. The site selected was Barnes S Tucker Lancashire No. 20 Mine located near Carrolltown, Cambria County, Pennsylvania. The system concept, operating and application software was designed and developed by the. British National Coal Board. The report describes the selection of the site, specification of the system requirements, commissioning, operation and evaluation of the system under typical US mine operating conditions. Experience with the system, based primarily on the system reliability and performance of conveyor control, was favourable. Mine management personnel felt that the system had successfully achieved its objectives and were keen to expand monitoring and control to other activities.

Jan 1, 1986

By Paul L. Michael

This report presents a discussion of perforance parameters for electronic or active hearing protectors that will meet the needs of underground coal miners. This information is incorporated into a proposed set of specifications that can be used to judge the suitability of a particular electronic hearing protector for the coal mine application. Acoustic and electrical tests were performed on a developmental model of an electronic hearing protector built by the U. S. Bureau of Mines. This model showed only a slight reduction in speech intelligibility which was traced to poorly matched components and in particular to the transducers. Tests of alternative components showed the Knowles BL-1671 microphone to be suitable for this application because of its performance and extremely small size. The Roan-well H-143/AIC earphone was found to have a good frequency response but has the disadvantage of being rather bulky which causes a slight degradation of a low frequency attenuation of the hearing protector. A satisfactory installation of these components in a hearing protector muff was demonstrated and tested. Results of tests of several methods of controlling the sound level under the hearing protector muff showed that a simple diode clipper circuit can be used with only a negligible loss in speech intelligibility for normal-hearing listeners. A commercially available active hearing protector, the British-built ACOS A-9000/2 was examined. This hearing protector provides sound level limiting through a saturating amplifier. Preliminary tests have shown that the performance characteristics of this commercial unit meet many of the proposed specifications so further testing and evaluation should be performed to determine its suitability for use 1n underground coal mines. The recommended test of intelligibility for electronic hearing protectors and other communication systems as used in a coal mine setting is the Modified Rhyme Test (MRT) developed by House et al. in 1965. The suitability and method of administering this test are discussed.

Jan 1, 1976

Underground coal mining continues to evolve in the U.S., and more reserves are being mined under deeper cover, with worse roof, or with interactions from previous workings. At the same time, the mining community is responding to higher safety standards and intense competitive pressures. The need for effective ground control design has never been greater. Ground control safety issues that have been addressed by recent the National Institute for Occupational Safety and Health (NIOSH) research include: Improving roof support performance; Maintaining safe tailgate escapeways from longwalls; Optimizing pillar design for retreat mining; Controlling multiple seam interactions; Predicting roof conditions during extended cuts, and; Preventing massive pillar collapses. As funding from both government and the private sector has diminished, the emphasis in research has focused on providing the mining community with practical techniques for improved ground control design. Many projects have successfully employed empirical methods that emphasize the statistical analysis of case histories from underground mines. Other projects have employed numerical models and large-scale laboratory testing of roof support elements. Using these data, NIOSH has developed an entire toolbox of computer programs that have been effectively transferred to the mining community.

By R. L. Grant

[p(,ton~to'rs 'ar-IV uscG.. to explode 9crnli .... sible c}:plosivcs, dynamites, or other hiGh uxplosives. This ?,...!xplosion or detr)nation is brought about by th\.:J energy which i liberated as a cOl":"Lb' nation of concusBion and heat wl1en the ? detonator is fired. 'm Ot:18t? I'l(jrds~ liThe detonator is the key VI: ich unlocks the enerGY of a llgh? explosIve""? (8) :1/. Being sensitive nd latently dangerous, detonators ITl.ust lTIeet t\V0 primary requirerDentr: They must be ..;.afe to handle and IT. list? detonate' when (l,esired, the ... eby iIr.parting deton:l.tion to the explo8ivc cJ.1Cire-e.]

Jan 1, 1941

By K. M. Connor, O&apos

Variations in overburden geology must be considered in applying subsidence prediction methodologies developed by the U.S. Bureau of Mines (USBM). To characterize rock mass overlying high-extraction coal mines, the USBM utilizes a computer spreadsheet program and modified Rock Mass Rating (RMR) system. The spreadsheet calculates an RMR based on a bed's engineering properties determined from core logs and laboratory tests. An in situ deformation modulus and a bending stiffness are computed for each bed. Stiffness-versus-depth plots identify groups of beds with similar stiffness. Large variations in stiffness between adjacent beds are considered significant horizontal discontinuities where slip is likely. Time domain reflectometry (TDR) is used to verify this hypothesis by measuring shear displacement along such discontinuities. A model of the overburden is built by assuming that a near-surface laminated beam exists above a transition zone in which large plastic slip occurs along horizontal discontinuities. Increasingly thicker groups of beds are modeled to determine the most probable beam thickness based on a comparison with measured deflection profiles. The inverse of maximum beam deflection is an index parameter known as "bridging potential," a single value that incorporates both overburden geology and mine geometry.

Jan 1, 2010

By Robert L. Lagace

The objective of this task was to perform theoretical analyses related to identifying and increasing the understanding of wireless propagation mechanisms in mines, and for predicting the performance ranges and limitations of proposed systems. This was to be achieved by building on and extending previous ADL work* and utilizing experimental data as they became available in the radio frequency bands of interest. B. TASKS Theoretical radio wave propagation investigations undertaken on this task centered on three areas. The first area dealt with extending previous UHF wireless propagation results*: to estimate the losses caused by the presence of haulage vehicles such as trains in coal mine tunnels; to estimate the propagation losses and wireless communication ranges expected along a longwall coal face tunnel; and to assess the applicability of previous analytical approximations to tunnels having reduced crossectional dimensions, such as those found in low coal and in the presence of haulage vehicles. The second area dealt with the development of a suitable propagation model to adequately explain the unexpected, highly favorable LF to MF band wireless radio wave propagation behavior experimentally observed in Consolidation Coal Co.'s Ireland mine. The third area dealt with the formulation of a model for evaluating the overall system transfer function and transmitter requirements for a hoist shaft LF communications system, taking into account the hoist rope/shaft transmission line characteristics, the cage and sheave wheel line terminations, the signal inductive couplers, and hoist shaft signal and noise data.

Jan 1, 1975

By Kevin Connor

During 1986, the Government continued with efforts to ease the country's almost total reliance on coffee exports for trade revenues by allocating 45% of the Government's budget to commerce and industrial projects. The collapse in coffee prices in 1985 continued to exacerbate the country's growing trade deficit, weakened currency, and dwindling reserves of foreign exchange in 1986. Amoco Burundi Petroleum Corp., a subsidiary of Amoco International Oil Co., continued with plans to drill at least two exploration wells in Lake Tanganyika in 1987. Both offshore and onshore drilling exploration was planned by Amoco Burundi. Any oil or gas finds were expected to have substantial impact on the Burundian economy, as a major portion of the country's trade deficit was directly attributable to petroleum and gas imports.

Jan 1, 1988

VOLUME I Volume I of this three-volume report is the result of development of a comprehensive, coordinated approach to site data-acquisition activities to produce key plans and reports during the evaluation and development of a surface coal mine. A logic diagram illustrates activities in the planning and decision-making process from exploration through post-mining monitoring. The report briefly discusses major elements, other than the site environment, which influence development of mining and reclamation plans and refers to other readily available literature for details outside the scope of this study. The essence of the rationale is shown to be the 1 employment of necessary skills at the proper time to evaluate specific data ' requirements and integrate them into a cost-effective program to produce initial and major feasibility reports, mining, and reclamation plans, and the environmental impact assessment.

Jan 1, 1976

By John B. Gayle

The Bureau of Mines has designed and constructed an experimental coke oven, using a commercial oven as a model where practicable. Because the rate of carbonization is important in determining the quality of the coke produced and may affect the "mount of pressure developed during carbonization, particular attention was given to those elements of the design that govern the heat transfer to the charge. The new oven deviates in design from most existing test ovens in that the charge is full width (17 inches), the heating walls ore constructed of 4-1/2-inch silica brick, and zoned, heat-input arrangements compensate for heat losses at the ends, top, and bottom of the charge. This report describes the oven, which was designed by H. S. Auvil and installed under his direction, at the Southern Experiment Station, Tuscaloosa, Ala., while he was supervising, engineer, Coke Section. It gives the results of a limited number of carbonizing tests. These results indicate that the main objective in designing and building this oven, that off duplicating commerical, slot-oven carbonizing conditions, has been accomplished; if coke-discharge conditions simulate commercial-oven conditions, the cokes from the experimental oven arc very similar to oven coke, in soma tests being fully as close is duplicate tests from a Angle batch of coke.

Jan 1, 1952

By S. H. Ash

THE INVESTIGATION of barrier pillars in the Western Middle field is part of the comprehensive study of the mine-water problem in the anthra¬cite region of Pennsylvania by the Federal Bureau of Mines (1, 2, 5, 6, 7, 8,9,10,11,1,2,15,16).8 The Western Middle field is in Schuylkill, Columbia, and Northumberland Counties in eastern Pennsylvania. It has an area of 120 square miles, is 42 miles long from Delano on the east to Trevorton on the west, and is 2 to 5 miles wide. In the Western Middle field are 58 underground water pools containing 38 billion gallons of water (5). Some of the pools overflow to the surface, and the water from others seeps into adjacent mines through permeable barrier pillars separating them from abandoned mines. Several active mines are interconnected to workings in abandoned mines, which are partly filled with water. These mines are separated by barrier pillars that are considered effective only below the altitude of the connections. In some abandoned mines, pumping stations maintain the water at altitudes where the hydrostatic pressure against the barrier pillars is not excessive and does not endanger adjacent active mines. If water in these abandoned mines is allowed to rise to where it can overflow into the active mines, it must be pumped from the active mines at lower altitudes; this materially increases the cost of pumping. It is estimated that from 1944 to 1948 approximately 30 percent of the water pumped to the surface was from abandoned mines.

Jan 1, 1953