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By Mark Sanders

This report describes an experiment which was conducted to compare the relative bumping hazard of a low and high profile hard hat (helmet) in a low seam mining environment. The study was specifically designed to assess the effect of lowering the helmet profile on frequency of head impacts in an underground low seam coal mine simulator. This involved subjects performing four common low coal mining tasks wearing the low and high profile helmets in the low seam simulator (36" and 48? heights). The results of the study indicated that a low profile helmet could reduce bumping frequency in underground low coal approximately 25%, and as much as 80% on selected tasks. It was beyond the scope of the study to measure the impact force, thus it was not possible to estimate the effect of the low profile helmet on severity of impacts underground. The research team recommended that a more extensive investigation be made of head injuries experienced in low seam mining (both underground and surface) with the objective being to assess the impact of a low profile helmet on total head accident exposure.

Jan 1, 1980

By R. B. Barlow, J. A. C. Fortescue

Originally developed for use in mineral exploration, regional geochemical mapping based on stream (and lake) sediment sampling is showing broader application in other areas of the earth sciences and in environmental science. The purpose of this paper is to focus attention on the role of regional geochemical mapping in relation to geological and environmental studies. This is achieved using a descriptive equation for the chemical composition of a stream-sediment sample and then relating it to the use of successive approximations in geochemical and environmental investigations. The procedure is further qualified with reference to time and process in the formation of regional geochemical patterns. Examples are included of studies based on stream sediments related to bedrock geology, surficial geology, ecology and man's effect on the geochemistry of the environment. The range of applications of regional geochemical mapping in earth and environmental studies is outlined and some conclusions drawn regarding the future development of geochemical mapping under Canadian conditions.

Jan 1, 1980

By M. F. Bucek

This report summarizes the activities performed and the results achieved during a two-phased investigation of the technical and economic feasibility of disposing of coal mine refuse underground in active mines, Three coal regions in the United States that are most severely affected by coal refuse disposal problems are identified: southwestern Pennsylvania, southern West Virginia, southwestern West Virginia and eastern Kentucky. For each region, a conceptual mine model is presented that describes the geologic conditions, mining methods, and environmental circumstances typical of that region. The model mine that was prepared for the Kanawha Region in Southwestern West Virginia and eastern Kentucky was selected as the basis for developing alternative conceptual designs of underground disposal systems in the second phase of this investigation. Procedures used in selecting the regions and in modeling typical mines are described in Part I of the report. Part II of the report describes existing methods for stowing refuse underground, presents three alternative conceptual designs of stowing system that would be appropriate for the model mine postulated in the first phase of the study, discusses technical characteristics and environmental effects relative to the various systems, and evaluates the technical and economic feasibility of the three alternative disposal system designs. Comparisons costs among systems and with costs or surface disposal are presented.

Jan 1, 1980

By Dipak Sengupta

This study analyzes the safety, technology, and economic impact of eliminating safety fuse from metal/nonmetal mines, based on operation and manufacturer experience over the past five to ten years. If safety fuse is eliminated, blasting accidents will decrease with no technical impact except for some limited, specific applications. The economic impact will be minor for large operations, but will be significant enough for small operations that some small operations will likely close rather than change. The majority of the mines would probably change over, with the extra cost absorbed by the market. Elimination of safety fuse would have obvious impact on the two manufacturers of safety fuse; one manufacturer already produces an alternative system, and will remain unaffected; the other will be affected if they do not change their production strategy. There will be a very minor effect on the mining industry as a whole due to abolishment of safety fuse from the standpoint of employment or production.

Jan 1, 1980

By Fred Leonard

This report is principally concerned with the engineering and economic feasibility of area surface coal mining systems other than draglines. This analysis evaluates shovel/ trucks, shovel/crusher/conveyors, and shovel/rail excavation and haulage systems for an assortment of geologic environments and production rates in the Powder River Basin (PRB). Shovel/trucks, front-end loaders trucks, and shovel/crusher/conveyors were studied in a multi-seam, dipping geologic area of the Four Corners Region. The Texas lignite engineering and economic research involved bucket-wheel excavators (BWE), BWE/backhoes, and scraper/backhoe combinations for overburden and coal excavation. The PRB truck/shovel study utilized the most recent computer simulation available in both the design and cost analyses. Detailed engineering analysis, followed by in-depth operating costs (operating and depreciation), result in a complete evaluation of each mining system. Cost comparisons of the different mining systems under similar geologic and production constraints are presented in the report to illustrate the estimated capital investment and production costs per ton of coal and bank cubic yard of overburden.

Jan 1, 1980

By W. C. Morgan

The Federal Surface Mining Law enacted in 1978 is now being translated into regulations which must be followed in future coal mining. Substantial change to mining procedures is required to maintain stricter air and water control while mining and to return the mined out land to equal or better use than before. These changes do not come easy; and in most cases, they create a substantial additional cost. Based on field observations and mining studies, Caterpillar has been making suggestions on the use of their types of equipment to conform to the new standards at the least cost. This paper will be a brief review of some of the overburden stripping and reclamation methods suggested by Caterpillar. A production and cost comparison of dragline, scraper/dozer and truck, loader systems in 20 to 150 ft. Overburden conditions illustrates potential cost savings using mobile equipment.

Jan 1, 1980

By Kenneth C. Ko

An engineering investigation was carried out on the technical and economic feasibility of implementing flexible liner/backpacking support systems In an advancing tailgate longwall mine. The system for a model mine consists of a circular tube constructed of liner plates and flyash backpacking. Flyash is pneumatically stowed into the tailgate. Small amounts of cement may be mixed to improve the support capability of the fill In difficult local ground conditions. Water is added inside the nozzle immediately prior to spraying. Results of theoretical analyses and a field test show that the designed system is technically feasible, can be cost-competitive, provides more stable ground conditions, and can Increase productivity and coal recovery, when compared with existing retreat longwall systems. In certain mine layouts, the new system can reduce the direct mining costs by a significant amount. The system would be particularly applicable to deeper coal beds with bad ground conditions.

Jan 1, 1980

By Edward A. McClatchie

A novel nondispersive electro-optical gas analyzer has been designed, fabricated and tested. The instrument is based on a pressure modulated absorption technique. Key features of this new gas analyzer technique include long-term zero and calibration stability. The technique was investigated for the gases carbon dioxide (CO2), carbon monoxide (CO), methane (CH4) and nitrogen dioxide (NO2). The delivered analyzer was capable of measuring the three species CO, CO2 and NO2. It is a compact (300 cu in) package, is battery powered and weighs 15 lbs. Some thirty readings of each gas may be made on a single battery charge.

Jan 1, 1980

By W. I. Watson

The study considered all the institutional, resource reserve, technological, and economic factors relevant to the industry's present and future status, such as markets and marketing techniques, competition from other producers both domestic and foreign, federal and state regulations affecting the industry, quarrying and processing technologies, slate reserves and resources, and industry structure and economics. Constraints to the growth of the industry were assessed and scenarios proposed to solve some of the problems.

Jan 1, 1980

The Bureau of Mines is responsible for a broad spectrum of programs for meeting the diverse and changing mineral resource needs of the Nation. These programs are managed by the Director and two Deputy Directors, who formulate general policy and program direction from the Washington, D.C., headquarters. A senior advisory staff, consisting of the Chief Staff Officer, Chief Scientist, and Chief Mining Engineer, provides advice and consultation to the Director on a wide range of scientific and technical matters and acts on behalf of the Director to maintain liaisons with other government agencies, mineral industries, and professional societies. Bureau program activities are classified into two major functions: (1) Developing new and improved technology that will make the production and processing of minerals more efficient, safer and more healthful for mineral workers and the public, and more compatible with a quality environment.

Jan 1, 1980

By G. J. Colaizzi

The Bureau of Mines, at the request of local authorities in Rock Springs, Wyo., investigated and conducted through contracts a multistage program of exploratory drilling and pumped-slurry backfilling of 15 areas of potential subsidence in abandoned mine workings underneath that community. Initially, the Bureau in 1969 had recommended a program of gravity blind flushing of some of the inaccessible mine voids, and in 1970 a new technique, the pumped-slurry injection process, was tested for the first time in a site adjacent to the city's area of severe surface subsidence. Success of this initial testing program, and of a large-scale project in Scranton, Pa., led to further large- scale projects, funded by Congress, that resulted in the successful back- filling not only of all 15 target areas of potential subsidence in Rock Springs, but also of several areas in other States. Total cost of the projects in Rock Springs, including the original pumped-slurry test, was $3,243,993. A total of about 923,000 tons of sand was injected hydraulically into mine voids, rendering 178 acres of residential and central-downtown areas of Rock Springs less susceptible to subsidence damage. The pumped-slurry method was proved to be much superior to the gravity blind flushing method in term of the amount of solids that could be injected underground through a single borehole. However, there are special conditions that make this technique more or less applicable in different areas or underground configurations, as noted in the report's conclusions.

Jan 1, 1980

By Frank C. Townsend

Centrifugal model embankments with varying geometries and materials were constructed of- coal waste material, accelerated From 100 to 120 times earth's gravity, and subjected to various throughflow rates until failure occurred. Complementary laboratory tests were performed on the waste materials to obtain strength and permeability parameters for analytical calculations to predict observed centrifugal model behavior. Failures in the form of deep.-seated failure, or erosion and sediment transport or a combination of both, occurred in model embankments with 1V:1-1/2H and 1V:2H slopes when the phreatic surface due to seepage exited on the downstream slope: Positive seepage control, i.e., a toe drain successfully prevented sloughing and failures. Slope stability analyses agreed well, albeit conservatively, with observed model performance. Factors of safety ranged from 0.7 to 1.02 at the instant of failure for models with retrogressing slips as compared with 1.05 to 1.7 for stable embankments, These models verified existing criteria of a minimum safety factor of 1 3 and the necessity of positive seepage control.

Jan 1, 1980

By Zsuzsanna Zborovszky

[Certain chapters of the tentative document entitled, "Test Requirements for instruments & Apparatus to be Considered for MESA Intrinsically Safe Certification" are evaluated and supporting data are presented on certain key issues with the purpose of helping the regulatory agency in improving the above document. The subjects discussed in detail are: hot wire ignition with W and BeCu wires; the most sensitive methane-air :and propane air ratio; the ignition limits for inductive-resistive circuits in 8.3°; methane-air mixtures in the 24-OV, 100 mH-2 [ ]H range, the resistive ignition limit as a special case when L ? 0; the capacitive-resistive ignition limit representing a four ,dimensional problem is analyzed and discussed in general and the variation of the ignition limit using Vo and/or r2 as a parameter are determined experimentally. The ignition limit is also determined for the [r1 ,~ r2] = 0 case ("capacitor alone") and for the most dangerous capacitive resistive circuit combination. The ignition limits are below the limits proposed in the document. A survey of the different factors influencing the ignition is made as to their suitability to provide a constant safety factor. It is shown that a constant safety factor cannot be achieved. The best method for applying a safety factor appears to be the increase of initial pressure or use of other gas mixture. The revision of the safety factor concept and ignition limit curves is recommended.]

Jan 1, 1980

By William N. Patterson

Drive systems for mining machines are usually sized to accommodate anticipated peak loads. Usually, the average power requirements are considerably less. Energy storage and power averaging are attractive concepts for mining machinery and could have far-reaching implications. The purpose of this program was to: ? Identify truly feasible concepts, ? Identify advantages/disadvantages, limitations, and constraints, ? Evaluate feasibility based on today?s technology, ? Identify anticipated safety problems, and ? Provide the designer with a comprehensive literature base. Concepts evaluated include flywheels, high energy batteries, gas charged accumulators, inductive storage, capacitive storage, springs and counterweights, thermal, closed cycles, internal combustion engines, trolley systems, and hybrid systems. A comprehensive reference index is provided. Included is an appendix containing abstracts of the pertinent literature.

Jan 1, 1980

By R P. Callaghan

Underground production from the low grade copper orebodies at Mount Lyell in recent years has involved surface subsidence of open cut areas. Relevant structural and lithological features of the geological environment are described. The highly mechanised underground mining system involves sublevel caving and sublevel open stoping with associated hanging wall cave. Monitoring of subsidence and caving has been made by regular visual inspection and measurement of crack development, and by surface profile surveys. These simple techniques have proved adequate in assuring management that ground movement is proceeding normally and safely.

Jan 1, 1980

By Dana T. Updyke

The objective of this project was to develop technical data and evaluate performance and utility of leaky feeder communications systems currently used in North American underground mines. The desired information was obtained principally through on-site surveys. Altogether, six of the seven mining companies known to be using leafy feeder communications were visited. This report covers the findings of these surveys. In addition, the report provides a brief background summary of mine communications, a technical discussion of leaky feeder systems, and conclusions and recommendations based on the results of the survey.

Jan 1, 1980

This appendix is composed of five sections, each of which is tabbed for ease of access. The sections are as follows: ? Fire incident report forms for underground mine fires. There is one form for each incident listed in Table II-1a. They are ordered chronologically with incident numbers corresponding to those in Table II-la. ? Fire incident report forms for surface mine fires. There is one form for each incident listed in Table II-lb. They are ordered chronologically with incident numbers corresponding to those in Table II-lb. ? Journal article report forms. There is one form for each article reviewed. They provide supplemental information to that contained in the fire incident report forms for selected fires. Index 11-14 keys the journal article report forms to the appropriate fire incident report forms. ? Non-reportable incident descriptions for underground mine fires. This is a listing of underground fires for which MSHA regulations do not require formal reports. ? Non-reportable incident descriptions for surface mines. This is a listing of surface fires for which MSHA regulations do not require formal reports. This appendix is intended to be used in conjunction with the tables and indexes contained in Volume II of this report and, as such, should be considered an integral part of Volume II. The indexes in the body of Volume II provide a means of ready reference to the underground and surface mine incident report forms. For those readers with interests other than those indexed, Tables II-la and II-1b can be used to locate specific incidents of interest. Complete incident information can then be obtained from the corresponding report forms in the first two sections of this appendix.

Jan 1, 1980

By Robert L. Lappi

Eight interburden handling concepts are developed for multiple seam area mine stripping operations in central and western United States. They are based on data gathered and analyzed during field surveys, literature reviews and visits to state requlatory agencies in five states. It is concluded that improvement of reclamation practices through selective interburden handling techniques is possible at lower operating costs than currently incurred. Specific multiple seam mining systems are discussed in this report.

Jan 1, 1980

By J. A. Kost

A survey of 80 coal producers was conducted to determine the extent and scope of respirable dust control research for underground coal mines and the current methods employed to control respirable dust. Results of the survey showed that proper face ventilation and an adequate water spray system are sufficient to comply with mandatory standards in room and pillar mining. Difficulties still exist with longwall equipment, auger miners and buring machines. In these cases, known dust control techniques are not sufficient to obtain compliance. Present state-of-the-art face ventilation and water systems were discussed in addition to the sampling program.

Jan 1, 1980

By Philip K. Hopke

A systematic study of the mechanism of interaction of 218Po(RaA) armed by the decay of 222Rn with airborne particulate matter has been made. The rate of attachment of RaA to particles in the diameter range of 0.1 µm to 10.0 µm has been measured as a function of particle size, concentration, and composition, radon concentration, time of interaction, relative humidity and temperature. It was found that under the conditions in these experiments the attachment rate was proportional to the square of the particle diameter and varied with temperature and relative humidity. The composition of the particles apparently has no effect on the attachment. The variation in attachment rate was related to a sticking probability coefficient of approximately 0.02 that varies systematically with temperature and humidity. In addition, the rate of deposition of RaA on the wall of the attachment kinetics system was measured and also found to change with temperature and relative humidity.

Jan 1, 1980