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By Herbert H. Einstein

Instability of rock slopes often occurs in the form of excessive movement of bodies that are bounded by discontinuities. The well known limit equilibrium analysis for wedges and blocks suffer, however, from procedural simplifications and from the basic deficiency of limit eguilibrium analysis--the rigid body assumption. Thus, stability analysis for 2-and 3-plane wedges with a wide range of additional features regarding failure modes and external forces have been developed. The deficiency, due to the rigid body assumption, was corrected by an approach that includes the effects or the in-situ stress field and of the stiffness of discontinuities. The final step in making limit equilibrium approaches more valid was achieved with the method of artificial supports which makes it possible to identify among all possible failure modes the critical one and to determine the corresponding factor of safety. The analytical development includes the creation of appropriate computer codes and routines for programmable pocket calculators.

Jan 1, 1979

By Irvin G. Burough

ANDROS INCORPORATED has designed, manufactured and delivered four handheld C02 DETECTORS and three handheld CH4 DETECTORS. These instruments are for in-mine safety use. The DETECTORS incorporated an NDIR optical/electronic analyzer design in which exceptional zero stability is achieved by pressure modulation of the sample gas. This eliminates the need for daily calibration. This stability and the miniature design (2.5" x 4.5" x 4.5"; 4.5 lbs) of the C02/CH4 DETECTORS provide practical instruments suitable for routine safety inspections. This report includes the theory and design of the instruments as well as studies of gas-pressure modulation by a piezoceramic-driven Helmholtz resonator.

Jan 1, 1979

This study assesses whether Narragansett Basin coal deposits could be developed commercially in the near future. To do this, we identify the potential market for the coal, assess the price these users would be willing to pay for Narragansett coal, and this price to the expected costs of producing Narragansett coal. The study concludes that the major market, New England utilities, could burn bituminous coal from Pennsylvania or West Virginia at a lower total cost than Narragansett Basin coal, assuming expected mining conditions and emission policies. Therefore, the study concludes that Narragansett Basin coal resources could not be developed economically in the next ten years.

Jan 1, 1979

By J. A. Kosek

Work has been conducted under Bureau of Mines Contract Number HO 357078 to develop instruments for detecting CO, NO and NO2 in a mine atmosphere, using fuel cell technology. The approach has been to optimize the fuel cell sensor configuration for the specific detection of CO, NO and NO2 in the presence of other mine gases utilizing recent advances in catalyst, electrode and solid polymer electrolyte membrane technology. Para-metric testing has been conducted on three electrode sensor cells to define performance and life characteristics as a function of temperature, feed flow and applied sensor voltage. Extended life testing has been performed on sensor cell configurations exhibiting favorable characteristics. Reliable, efficient gas sampling and electronic control circuitry has been fabricated for use with the sensor cells, and integrated into devices to meet the performance and design specifications for portable, battery-powered, hand held direct indicating gas detectors for use underground. Twenty of the production-type, direct indicating CO detectors have been tested and delivered to the Bureau of Mines under the present contract. Three prototype diffusion head CO monitors have also been delivered for evaluation under the pre-sent contract. The gas sampling pump and related parts have been replaced by a diffusion tube assembly in which CO reaches the sensing electrode surface by diffusion alone. In addition, delivery will be made of ten direct-indicating nitric oxide detectors and ten direct-indicating nitrogen dioxide detectors. These instruments are very similar in design to the direct indicating CO detector.

Jan 1, 1979

By Clifford B. Farris

The natural cementation strength of retorted oil shale is the focus of this investigation. The optimum retorting temperature and residence time to obtain natural cementation strength in retorted Green River oil shale from western Colorado were determined as follows: [Optimum Conditions for Natural Cementation Maximum Residence Obtained Retorting Time at Compressive Mode of Temperature Temperature Strength' Retorting °F °C hr psikg/cm-2 Direct 1,520 822 2.0 270 19.0 Indirect 1,530 832 2.9 325 22.8] 1 Scattered samples were tested at strengths as high as 463 psi (32.6 k /cm 2) (Run 8, indirect mode) and 406 psi (28.5 kg/cm2) (Run 48, direct mode), but these high strengths were not confirmed by nearby tests. Minus 0.5-inch (1.3-cm) Green River oil shale was heated in a differential retort under conditions simulating potential full-scale retorting processes. The variables investigated were retorting temperature, residence time, retorting mode, and shale grade. Samples of the retorted Green River oil shale were moistened to optimum plus 2% (25%) moisture, compacted to 95% Proctor density, sealed and cured at 100°F (38° C) for up to 40 days. Lower curing temperatures, which are likely in the field, would probably result in significantly slower development of cementation strength, and might lower the ultimate strength developed. However, these effects were not studied in this project. The cured samples were tested for compressive strength, and correlative equations were developed for the increase of compressive strength with curing time as a function of retorting temperatures and residence time. Petrographic analysis indicated that the cementing mechanisms may be the interlocking growth of acicular hydrated calcium aluminum sulfate crystals between the contacts of retorted shale fragments. Samples of the retorted shale were also tested for optimum Proctor density and moisture. Permeability and quality of the leachate of shale from typical runs were determined. The effect of use of retort rather than tap water on compressive strength and leachate after curing was determined. The retorted shale effectively filtered several mineral constituents from the retort water.

Jan 1, 1979

This document is Volume II of a two-volume report on underground and surface coal mine fires occurring between 1950 and 1977. Volume I discusses the methods of data acquisition, data analysis procedures, results and conclusions. This volume contains (1) a master list of all fire incidents obtained from MSHA reports, (2) an annotated bibliography of all MSHA reports, journal articles on selected incidents, and non-reportable fires (appendix), and (3) indexes to be used in accessing incidents in the master list and annotated bibliography. These three types of information provide the reader with a complete summary of coal mine fires during the period from 1950 through 1977 and a convenient means to locate incidents of specific interest. The body of this volume is organized around two tables and a series of indexes. The two tables are master lists of underground and surface fire incidents. They are followed by 14 indexes keyed to the master list and annotated bibliography. The appendix contains three different parts: o The annotated bibliography of MSHA fire reports (one section each for underground and surface mine fires) o The annotated bibliography of journal articles about selected fires from the MSHA bibliography o A listing of non-reportable fires (one section each for underground and surface mine fires) Descriptions of the contents and use of each of the three major components of this volume (i.e., master list, indexes, and appendix) are presented in Section 2.0.

Jan 1, 1979

By G. B. Clark

One portion of this project was to test a blast shield and to design some features for a novel tunneling method termed the Automated Drill and Blast System (ADBS). The ADBS tunneling concept was developed for the design of an excavation system of greater efficiency than conventional drill, blast, and muck (DBM) systems by minimizing the down time and approaching the non-cyclic efficiency of continuous tunneling by means of small charge blasting. Small charge blasting uses simultaneously detonated, small light charges (less than 200 grams per hole) in four to eight shallow (24 to 36 in. deep) holes usually in a line. Limitation of the total explosive per blast reduced air blast overpressure, fly rock velocity, vibration, and noise. Thus, shielded equipment can remain at the face and a tunnel shield permits support personnel to work outby the shield at all times. The ADBS equipment will be composed of five components: (1) a chassis, upon which is mounted automated mucking equipment, and a frame which carries (2) the hydraulic drill(s), (3) load/blast system(s), and (4) control cab(s). The blast shield may have its own mounting. Ventilation, horizontal, and vertical alignment controls are incorporated in the system. The blast sheild, which protects personnel outby the advance equipment from air blast overpressure, fly rock, and gases, was tested with full scale small charge blasting. A blast shield was designed, fabricated, and tested under conditions anticipated for a working model. The shield was designed to expand to fit the tunnel shape, to seal itself to the tunnel periphery, and to contain air blast, fly rock, and gaseous explosion products. In addition, the shield, which was lined on the inby side with rubber belting, reduced the blast noise level outby the shield to 113 dBA or less, which is very near permissible levels. The test results show conclusively that the shield concept is viable. Based partially on the shield tests, a blast resistant control cab was designed to be located on the equipment chassis inby the blast shield to protect operators during blasting, and to contain all the controls necessary for system operation and safety. The economics of tunnel driving using the ADBS were compared with those of DBM. Four rock types, which determine advance rate, and four cost categories were examined. The results of this analysis are as follows: 1. ADBS advance rate is faster because equipment remains at the face and operation procedes semi-continuously. 2. ADBS bit and explosive cost (which accounts for 4%o of the total advance cost) is higher than for DBM. 3. ADBS equipment cost, on a per foot basis, is lower than for DBM. 4. Due to a reduced labor force, ADBS labor cost is lower than for DBM. 5. Because of the overbreak reduction due to controlled blasting, ADBS tunnel support cost is lower than for DBM. 6. On a per foot basis, total ADBS advance cost is from 17% to 20% lower than for DBM, depending on tunnel diameter and rock type. The small charge method greatly reduces ground vibration, increases personnel safety by limiting excessive fracture, and decreases tunnel support requirements by reducing overbreak. The overall analysis, tests, and results to date show that the Automated Drill and Blast System may be developed into a viable tunnel excavation method. The method also may be adapted to use in the mining of ore. For some types of mining operations, the cyclic nature of conventional drill and blast methods may not be a disadvantage, either where the drilling and mucking may proceed simultaneously or where the operations are carried out in adjacent working faces. The proposed method would find application where continuous methods of excavation are desirable.

Jan 1, 1979

By Walter W. Kaufman

This report summarizes a study conducted to determine the state of the art of various rock removal systems and their capabilities. The objective of the study was to determine if currently manufactured equipment can adequately accomplish rock removal in surface mine reclamation applications. Evaluations of state reclamation regulations, with regard to topsoil rock content, were made to determine the rock removal requirements. The major categories of equipment studied are rock pickers and rock rakes. The impact of rock removal implementation on the reclamation operations is discussed in detail.

Jan 1, 1979

1. Domestic Production and Use: In 1978, 12 companies operated 31 primary aluminum reduction plants, with 3 firms accounting for 65% of production capacity. Washington, Oregon, and Montana accounted for 31% of the total capacity; Gulf Coast States 23%; Northern States 26%; and other Southern States 20%. Based on published producer prices, output of primary metal in 1978 was valued at $5 billion. Aluminum consumption by 25,000 firms was centered in the East Central United States. Of aluminum consuming industries in 1978, building accounted for about 25%; packaging 22%; transportation 23%; electrical 11%; consumer durables 8%; and other uses 11%.

Jan 1, 1979

By John Kosek

The electrochemistry of carbon monoxide, nitric oxide and nitrogen dioxide was investigated at a variety of electrode materials in different supporting electrolytes. A portable detector for carbon monoxide was developed using a porous gold anode in perchloric acid supporting electrolyte. This detector has two full scale ranges, 0-100 ppm and 0-500 ppm. A portable detector for mixtures of nitric oxide and nitrogen dioxide was developed using a porous silver cathode in sulfuric acid supporting electrolyte. Nitrogen dioxide was determined in the gas stream by electroreduction. The nitric oxide in the gas stream was oxidized to nitrogen dioxide by passing it over Cr(VI) on firebrick. Electroreduction gave the sum of NO + N02. Analog circuitry was used to display the amounts of NO and N02 separately. Two ranges were available for each gas. They were 0-10 and 0-50 ppm for NO and 0-2 and 0-10 ppm for N02.

Jan 1, 1979

By Glenn Adkins

This report characterizes pivoting joints in the structures of mining machinery and how the wear on the various components, i.e., pins, lugs, yokes and bushings, may affect the safety of mine personnel where these components are allowed to wear excessively before repair or replacement.

Jan 1, 1979

By Dennis E. Jensen

Field studies were performed during blasting operations for strip coal mining above the room and pillar workings at Jenny mine in eastern Kentucky. The study is part of the Bureau of Mines program to develop criteria for the proximity of surface blasting to underground mines. Measurements and observations were made to identify physical changes in the mine. No change in the frequency of roof falls or any other indication of apparent damage was noted. Recordings of blast induced vibrations were made using sensors on the roof and floor of the underground mine and at the ground surface. A maximum particle velocity of 17.5 in/sec was recorded on the mine roof. The vibration data were analyzed and comparisons were made between roof vibration levels and those recorded on the mine floor and at the ground surface. Results are compared with previous blast vibration studies. Recommendations are made for further study toward developing criteria.

Jan 1, 1979

By Robert P. Bruno

This report covers the study of the feasibility of using a hand-held infrared viewer as a methane indicator to observe methane gas at the face of an underground coal mine. The objective of this program was the development of a hand-held device to remotely detect the presence of concentrations of methane gas in underground coal mines. Convenient "mapping" of methane from a remote location would allow rapid and safe corrective procedures for working personnel. Modified commercially available equipment was evaluated both in the laboratory and in a working mine. Although readings were obtained and the general principle of operation demonstrated, the power levels necessary, and protective enclosures required, would raise the weight of the instrument beyond practical limits of portability. Based on currently available technology, it is the conclusion of the investigations that a practical, portable, hand-held visual methane indicator is beyond the state-of-the-art. The recommendation was, therefore, made that work be suspended, and the results and data compiled and presented in a final program report.

Jan 1, 1979

This report summarizes the results of the Narragansett Win Projec't's activities during the U.S. Bureau of Mines (BOM) Phase 1, which was transitional from and which followed the National Science Foundation (NSF) Phase which initiated the investigation of New England's potential roil resource. The 960 sq. mile basin is structural and topographic lowland containing 12,000 to 20,000 ft. of terrigenous clastic sediments of late Pennsylvanian age, and which rests on an upper Precambrian and Cambrian basement. The Rhode Island Formation, which is the coal-bearing unit, comprising the bulk of the Pennsylvanian rocks consists, in order of decreasing abundance, of sandstone, conglomerate, silts tone, shale, and coal. In the NSF Phase, 24 drill-holes yielded 17,900 ft, of core; in the BOM Phase I study, 4 drillholes yielded 2,100 ft. of core. Anthracite and semi-anthracite was encountered in beds Up to 30 ft. thick in widely spaced parts of the Basin. The coal, typically very low in sulfur, and a high ash anthracite, won mined in substantial volumes from 1808 to 1959 from shaft and open lit in Portsmouth and Cranston, R.I., and in lesser volumes in Mansfield, Mass. Currently coal is now being mined in Plainville, Mass. as a fuel in the manufacturing of light-weight aggregate from the same quarry that serves as the source of the rock being processed. The structurally complex Narragansett Basin is now known to have a greater extent than earlier since recent drilling by others (Chapter 2) has confirmed our interpretation that the Basin extended offshore south A Boston. The, Basin also extends into Rhode Island Sound to the south. The geological structure is more complex in the southern part of the Basin than in the northern part. Three episodes of folding have been documented on Aquidneck Island and four episodes of faulting have been demonstrated for the Basin as a whole. Relatively less well exposed rock in the northern part of the Basin, increases the difficulty of recognizing and correlating structural episodes in the northern part of the Basin. The Basin his hewn subdivided into six structural domains which appear to have distinctive structural, metamorphic, paleontological and sedimentological differences that mw assist in isolating important events in the evolution of the Basin and its component parts. The tentative structural model recently developed in POP Phase I has important implications for exploration and mining. In the first and second folding stages the coal is mobilized and thickened in the crests and troughs of folds whose axes are horizontal to subhorizontal. While conventional coal exploration and mining methods are not applicable, great thickening in the crests and troughs of large scale structures, which can he defined by geology, geophysics and drilling, may provide compensating advantages. Bedrock over most of the Basin is 0-50 ft., but thicknesses of glacial deposits up to 150 ft. are present locally. Pro-Pleistocene topographic trends are controlled by structure and rock hardness; Pleistocene deposits aligned to the S. F. are superimposed on earlier trends. The southern part of the Basin is mainly dominated by high grade Barrovian metamorphism and plutonism of Permian age, related to the Alleghanian Orogeny. About 300 sq. miles of the 960 sq. mile Basin has been affected. The remaining 660 sq. miles, in the chlorite and subchlorite zones of metamorphism are compatible with the presence of high quality anthracite and semi-anthracite. Illite crystallinity studies begun in the NSF Phase, have been carried out in the BOM Phase l with important results. About ME of the northern Basin is now known to be in the diagenetic (unmetamorphosed) or subchlorite zone and the remainder in the chlorite zone of metamorphism. Mite studies, probably best recording temperature effects, show a generally progressive increase from the NW corner of the Basin near Plainville, Mass. toward the south and southeast. Reflectivity and coal petrography studies, probably best recording pressure and effects related to shearing, indicate a generally opposite pattern. Thus these methods provide powerful tools for the ultimate solution of problems important to coal exploration for coals of higher combustible volatile content and exploitation of these. Due to the complex nature of the coal, chemical data may not he easily used to determine rank. The coals have been tectonically deformed and mineralized. This deformation plus thermal metamorphism have altered the coals, in some cases by producing natural coke. Brecciated coal is often coated with a secondary depositional carbon. The coals' hydroscopic nature and high ash contents are due to the deformed nature of the coal and the presence of this secondary carbon. The stratigraphy and sedimentology of the coal-bearing Rhode Island Formation is similar to described alluvial fan deposits. The non-geological studies al-low three conclusions to be made: 1. A substantial number of areas have been identified in the Narragansett Basin in which mining could be carried out without undue difficulty from a land use point of view. 2. Substantially more than two hundred instances of past or current- mining activities have been identified in the Basin. Many of those are in areas defined as geologically interesting, and may be advantageous From the point of view of future exploration. 3. The map synthesis technique developed for this contract is successful and may easily be adapted to future exploration in its current form and also in its expandable form dealing with unit measurements of one-tenth mile. We recommend that BOM Phase 2 exploration should accomplish the intent of the Congressional language in House Report No. 95-1251, to continue a substantial drilling and geophysics program: "The Committee expects the Bureau to continue studies involved in ascertaining the extent and quality of low sulfur coal reserves in the Narragansett Basin in New England including necessary drilling and geophysical studies. The knowledge of the extent of such deposits is of great importance to this 'energy pour' area".

Jan 1, 1979

1.0 Control House (DWG. NO. 56-401-G) - 1.1 Physical Description The Control House is a single story, 2728 square foot building with an adjacent transformer yard. A four foot overhang provides shade protection for the walls. The building is heated and air conditioned. The HVAC System has an elevated outside air intake and provides a positive pressure environment within the structure in order to prevent the infiltration of heavier-than-air, noxious gases. The materials of construction are as follows: Structure : Light-Gage Metal Framing Exterior Walls :Outside - Preformed, Metal Siding :Inside - Insulated Metal Liner Panels Interior Partitions :Gypsum Board over Light-Gage Metal Framing Roof :Insulated, Preformed Metal Panels Ceilings :Mechanical & Electrical Rooms - Exposed underside of Roof Panels Control Room, Lunch Room, Toilets, Entry - Suspended Acoustical Lay-In Tile Floors :Mechanical & Electrical Rooms - Concrete Slab on Grade Control Room, Lunch Room, Toilets, Entry - Resilient Tile Exterior Doorsand Windows :Preformed Metal Panel Manufacturer's Standard Units

Jan 1, 1979

By Dennis R. Kasper

This study evaluates selective environmental impacts of two distinct in situ mining techniques. In situ leaching of uranium, porphyry copper and native copper and in situ borehole (slurry) mining of uranium, sandstone, and pebble phosphate ores are the techniques and minerals investigated. The potential impacts onsite in the desert southwest (porphyry copper), Michigan (native copper), Texas and Wyoming (uranium), and Florida and North Carolina (phosphate) are addressed and discussed. The study emphasizes those impacts which are unique to in situ solution leaching and borehole slurry mining. Impacts which are characteristic of all construction projects in the general geographical areas investigated, such as socioeconomic effects on surrounding communities and site-specific impacts, such as rare and endangered species, are beyond the scope of this study. For each of the in situ processes and associated ores investigated, the physical and chemical characteristics of the systems are described, the toxicity of the leaching solutions are presented, and the potential impacts on the environment are developed.

Jan 1, 1979

By Frederick C. Kohout

An advanced water-in-oil emulsion hydraulic fluid has been developed which meets defined laboratory performance criteria and which has given fully satisfactory results in a one-year underground mine test in two continuous miners. A novel method of monitoring fluid water content was demonstrated and incorporated into a test kit for use at or near the mine site. Test fluid fire resistance integrity as measured by the MSHA Schedule 30 procedure was maintained during the test and important fire resistance test variables identified.

Jan 1, 1979

By Philip B. Grote

The deep ocean mining industry is in a pre-commercialization stage of development. In the context of a proper legal/regulatory regime, deep ocean mining system design, site survey, and operation technologies are capable of rapid evolution. The report recommends that the regulatory framework develop in parallel with the industry and presents a rationale for implementing this approach. The Government has several interests in deep ocean mining technology: (1) as a potential regulator, sound regulations should be based on an understanding of the technology; (2) as a potential monitor, survey technologies are relevant; and (3) as an estimator of strategic minerals supplies, it is important to understand the technology which allows economic access to deep ocean minerals. Thus, the major portion of the report presents an in-depth review of systems design, operations, and survey equipment and techniques.

Jan 1, 1979

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 F. S. Kendorski

This report presents the results of a search for viable-self-drilling roof bolt concepts, detailed development, design, and manufacture of such bolts that drill their own holes, and testing in the laboratory and in the field in two different coal mines of three self-drilling roof bolts. Three new types of bolts were designed and tested, which drill their own holes and then anchor in continuous operation. These were a spring-actuated mechanical expansion shell, a slot and wedge, and a self-contained resin anchor bolt. Such bolts when fully developed for mine use would allow safer and remote installation of ground support and increase productivity. Recommendations are given for further work to improve drilling and anchorage performance.

Jan 1, 1979