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By Normal Seidle

This report (rind related Appendices) provides a description of the functional design specifications and related rationale for development of a training system for dragline equipment operators. Phase I activities involved a delineation and detailed analysis of specific behavioral requirements for successful dragline operation. Following the field data collection effort, job/activity/task descriptions were formulated into training requirements which can be achieved by a trainee with training hardware having specific functional capabilities. The training system analysis integrated the training requirements and the trainer functional capabilities into recommendations which configure a total training system. The objective of the training system described in this report is to provide new operators of dragline equipment with the requisite skills and knowledge to assure cost-effective development and an adequate supply of our human resources.

Jan 1, 1975

By Mark P. Meyer

A mineral investigation of the Chugach National Forest, Alaska was conducted jointly by the U.S. Geological Survey and the U.S. Bureau of Mines from 1979 to 1983 as part of the RARE II program. The U. S. Geological Survey remapped the geology and distribution of mineral resources. The Bureau investigated mines, prospects, and mineral occurrences. Previously unreported mineralization in three areas, Long Bay, Wells Bay, and Miners River were discovered in the western portion of the SOUND study area. Copper, lead, zinc, gold, silver, nickel, cobalt, fluorite, and arsenic were found in north-northeast to north-northwest trending shear zones, veins, felsic dikes, and granitic intrusives in Tertiary Orca Group metasedimentary rocks.

Jan 1, 2011

By Oliver Bowles

Marble is one of tile most beautiful and enduring materials employed in the construction industries. Because of its diverse colors, decorative patterns, and varying textures, it has furnished material for artistic architectural design for many centuries. The marble industry is described in some detail in Bureau of Mines Bulletin 106, The Technology of Marble Quarrying, which, unfortunately, is now out of print but may be consul ted at most large libraries. Onyx marble and travertine are discussed in Bureau of Mines Information Circular 6751. The purpose of this paper is to describe the main features of a distinctive group of ornamental marbles known as the serpentine marbles or verde antiques.

Jan 1, 1938

By D. Harrington

The code of hoisting signals for use in mines hoisting from one level, as suggested in this publication, is submitted to induce consideration of this subject by representative groups of the coal-mining industry, such as the lithe Inspectors Institute of America, National Coal Association, American Mining Congress, and others, as well as to -furnish a code of signals for use in those mines operated in States that do not have regulatory hoisting codes in their mining laws, or regulations. The signal codes described in this publication apply only to mines hoisting from one level and to slope mines. Mines that hoist from more than one level are referred to Bureau of Mines Information Circular 7289 Suggested Hoisting-Signal Code For Metal Mine Shafts, which suggests signals for hoisting from various levels or stations.

Jan 1, 1944

By Daniel R. Walton

A study to explore the potential of utilizing the transport time required to move coal miners to and from the working sections. Consideration was given to all forms of training and presentation media, taking into account such environmental factors as noise, dynamic interferences, visibility, physical constraints, and contaminants. Indications of managements? and workers' attitudes toward man-trip training were also assessed. The final product was a proposed prototype training system for man-trip training. Includes Bibliography.

Jan 1, 1979

By T. A. Henrie

One objective of Project Gnome is to study the feasibility of a phase of the Plowshare program recovering thermal energy from an underground nuclear explosion. The test will be conducted in an underground salt deposit. It is anticipated that some of the energy thus released will be stored as thermal energy in molten salt. This report describes the pre-Gnome experiments conducted at the Federal Bureau of Mines Metallurgy Research Laboratory, Boulder City, Nev. The objectives of this study were to determine the problems involved in the recovery of thermal energy from molten salts to assist in planning the experimental program for the Gnome project.

Jan 1, 1961

By Sheridan J. Rodgers

Improved methods of dust control in the metal and nonmetal mining industries were studied. Preliminary dust surveys were made at selected mines and three mines were chosen for additional studies. Dust control effectiveness was evaluated using full shift gravimetric sampling and GCA Dust Monitor readings. Analyses for free silica content and particle size distribution were conducted. A belt washing system which was used to control dust at a transfer point was evaluated. The average reduction of respirable dust was 48% and the average reduction of total dust was 78%. The belt washing system not only maintained the work place within compliance but reduced maintenance problems along the beltway by 90%. Exhaust ventilation at a crusher was evaluated for control effectiveness. Ventilation along with operation of the crusher control room under slight positive pressure, maintained the work place within compliance. An exhaust ventilation system was designed for use at an underground rotary dump. Although the system was not installed or evaluated, details on the design are given. High expansion foam was used at an ore chute in an attempt to control dust at the draw point and loading point. Results indicated that foam did not effectively control dust.

Jan 1, 1978

By Robert W. Waytulonis

This publication contains 1,000 citations of technical and semi-technical literature treating diesel-powered equipment usage underground both generally and specifically. These citations were gathered by U.S. Bureau of Mines personnel over the period of 1978-1983. The citations concern diesel engines as powerplants for underground mining use; their design, emission characteristics and control, maintenance, usage; and health and safety aspects. All citations have been abstracted and arranged 1n a subject classification system with extensive cross-referencing.

Jan 1, 1983

By H. L. Riley

Cleaning and handling of fine coal are generally conceded to be more difficult problems than preparation of the coarser sizes. Increased mechanization in the coal-mining industry has, in general, resulted in an increased percentage of the fine sizes in the total coal mined. If the coal fines are cleaned by wet methods, the minus-1/16-inch square-mesh particles cause most of the sludge and slurry problems encountered in preparing wet coal. Equipment that separates coal from refuse on the basis of specific gravity is not efficient on sizes that, because of their fineness, do not follow the same laws of hindered settling as the larger particles. Probably the best solution of fine-coal cleaning problems is to use other methods, such as flotation, that utilize other physical characteristics than those determining hindered-settling ratios. Regarding the type of flotation known as the Elmore vacuum-flotation process there has been a scarcity of data and information available in this country. An investigation has therefore been made to obtain additional date and information on this process under laboratory conditions. During this investigation an effort has been made to evaluate the relative efficiencies of vacuum and mechanical laboratory froth flotation cells. The investigation included float-and-sink, screen-sizing, and flotation tests on 2 different samples of 14-mesh to 0 raw coal and an a sample of slurry from the settling-tank overflow of a typical washer. One raw-coal sample was obtained from the American bed and represented a type of coal that is relatively easy to clean. The other raw-coal sample was from the Mary lee bed and represented a type considered difficult to clean.

Jan 1, 1954

This Bureau of Mines publication contains five papers pertaining to the effective grounding of mine power systems, as follows: Ground-check monitor types and safety characteristics; ground wire monitors for surface coal mines; ground bed design and measurement; electrical ground rod corrosion; and a continuous ground bed resistance monitor.

Jan 1, 1979

By Arthur M. Hartstein

The Federal Bureau of Mines, under a contract with Ultrasystems, Inc., investigated the thermal oxidative degradation characteristics of conveyor belts used in underground mines. This included the determination of smoke evolution, glow characteristics, char yields, and the identification and quantification of all volatile decomposition products in the form of gram of specific product formed per gram of belt sample tested. In addition to these investigations, degradation studies were conducted on some pure ingredients used in conveyor-belt formulations. Three basic classes of belts were investigated: neoprene, polyvinyl chloride, and styrene-butadiene rubber compositions. The studies indicate that styrene-butadiene-based belts exhibit good flame resistance and are the least hazardous in regard to overall formation of toxic decomposition products. Under this program, thermogravimetric analysis was definitely established as a method of material differentiation.

Jan 1, 1976

By Maria I. De Rosa

High temperatures encountered by mine rescue teams during emergency situations may cause severe physiological strain, hindering the men from carrying out rescue and recovery missions. A prototype ice-cooling garment (ICG) was developed by the Bureau of Mines to alleviate physiological strain due to heat stress. The effectiveness of the garment was tested with acclimatized and unacclimatized subjects at a typical work rate (1,200 Btu/hr) expected during rescue operations and at various hot environments (97° to 113° F dry bulb and 80° to 89° F wet bulb). During exposures with the ice cooling garment, the subjects were able to maintain a safe deep body temperature of 100.4° F or below Without the garment, the deep body temperature rose beyond values of 100.4° F, a condition considered unsafe for continuous work in hot conditions. Both heart rate and skin temperature values were lower while wearing the ICG. Subjective observation also indicated a marked benefit by wearing the ICG.

Jan 1, 1976

By H. G. Wolfhard

The propagation of explosions through short cylindrical channels has been investigated by the Bureau of Mines. In the experimental apparatus set up by the Bureau, a single such channel formed a connection between a small explosion vessel in which a gaseous explosion was initiated and a larger, partly enclosing, explosion vessel filled with suitable gaseous mixtures; the larger vessel permitted observation to determine if an explosion was induced therein by mass, energy, and species transfer through the channel, as a result of tie initial explosion, It has been found that transmission of flame through to channel is not an essential to induce the second explosion, for hot gases from an extinguished explosion are able to ignite cold combustible mixtures in the larger vessel. The schlieren patterns of flames or hot burned gases emerging from a channel into the explosion chamber were photographed. These show, in most instances, that vortexes of hot gas ejected from the jet into the cold explosive mixture are responsible for ignition. The study has practical significance in problems of rendering electrical equipment safe for use in potentially flammable atmospheres, INTRODUCTION The propagation of flames through cylindrical or annular channels has practical importance in flameproofing electrical equipment and for flame traps. Much practical work has been done to determine the minimum safe breadth of flanges and the maximum safe gap between the flanges that will permit venting an electric motor without allowing flames to pass.

Jan 1, 1959

By James R. Aggson

This Bureau of Mines report describes floor heave ground control problems that have been encountered in a new underground coal mine in West Virginia. Previous experience in the coal seam, the results of physical property investigations, and in situ rock stress determinations are discussed. The apparent cause of the ground control problems is the existence of a high, biaxial, horizontal stress field coupled with a floor member that has time-dependent deformation characteristics, A theoretical analysis of the failure process is developed. The analysis is assisted by finite element techniques. Mine design recommendations based on this analysis are presented.

Jan 1, 1978

The investigation summarized in this report addressed two primary issues: the determination and use of correction factors, and the development of guidelines for velocity measurement site selection. Other ancillary issues which were addressed include a comparison of measurement methods and devices, aircourse cross-sectional area measurement, and characteristics of mine airways. An exhaustive literature search and analysis was performed; extensive in-mine experiments were conducted; a quantitative analysis of the data was used to develop correction factor tables and site selection guidelines. The reported results of other researchers who have examined the correction factors and site selection criteria, were analyzed in light of the results of this study. The measurement devices included in the experimental phase were: vane anemometer, vortex shedding anemometer, a prototype thermoanemometer, smoke tube, and, oil of wintergreen. The measurement methods include single-point centerline, timed¬-point traverse, continuous traverse for the anemometers, and various distances and cloud positions for the smoke tube and oil of wintergreen devices.

Jan 1, 1983

By P. M. Daling

This report, sponsored by the U.S. Bureau of Mines, presents the results of an examination of the safety of the impactor shaft sinking system in comparison to conventional shaft sinking technology. Detailed study of the impactor system was also performed to identify and recommend design changes for optimum safety conditions. A comparison of the impactor machine and its support systems with conventional shaft sinking was made on the basis of relative risk levels. Risk incorporates measures of both the frequency and the potential consequence of accidents. A safety evaluation of the component operations of the impactor shaft sinking system was performed using a Failure Modes and Effects Analysis (FMEA) methodology. The results of this analysis show generally that the impactor shaft sinking system is safer than conventional shaft sinking. The potential risk of conventional shaft sinking operations could be reduced by an average of over 35 percent with use of the impactor shaft sinking system. Design change recommendations to further improve the safety of the impactor system include a revised fire suppression system, improved access to and from the operator cabs, reliable noise attenuation measures, and improved communication systems. An operational safety manual was also developed for the impactor shaft sinking system.

Jan 1, 1982

By D. R. Tesarik

To ensure the stability ofa tailings pond embankment, the height of the phreatic surface must be kept at or below a safe level. In this investigation, the Bureau of Mines analyzed various horizontal drain designs for tailings embankments to determine their effects on location of the phreatic surface. This report describes the investigation, and it includes 21 dimensionless graphs that can be used to estimate the drain spacing and length dimensions necessary to ensure the stability of embankments of various configurations. Analyses were based on the use of two computer codes, a three-dimensional finite-element code and a two-dimensional finite-difference code. The computer-generated results were compared with results obtained from a laboratory embankment model, other laboratory test results, and piezomet-ric data from two actual tailings embankments. Nearly the same phreatic surface locations were predicted using either of the computer codes. For one of the actual embankments studied, the predicted phreatic surface location was slightly higher than the measured location; for the other, the predicted location closely followed the actual surface trend. Phreatic surfaces of the laboratory model were slightly higher than the code-gener-ated locations, and the differences grew larger as drain length increased or drain spacing decreased.

Jan 1, 1984

By M. R. Geer

Efforts to evaluate washery performance are nearly as old as the art of coal cleaning, and in former years there was no uniformity in either the methods used or the basic terminology employed. This situation, and the con- fusion it bred, prevailed until about the time of the First International Coal Preparation Conference in 1950, Largely because of the interest of the French coal research organization Cerchar, the subject of evaluating performance was given prime importance at this conference. As a result, there is now a much greater degree of uniformity in terminology and methods of expressing cleaning results. The International Standards Organization currently is working toward international standards of terminology and methods that should improve the situation even more. The various criteria that are used to evaluate the performance of coal- cleaning equipment fall into three categories, depending upon the extent to which they are dependent on the density composition of the raw coal; some are directly dependent, others are only indirectly dependent, and still others are substantially indenpendent.

Jan 1, 1962

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 A. E. Raddatz

In an attempt to develop technology to use domestic resources in place of imported bauxita, the Bureau of Mines investigated sulfurous acid leaching to extract alumina from kaolin. The process consists of leaching the calcined kaolin with a 30 wt-pct S02 solution at 60° C and 160 psig for 17 hours, fil¬tering the leach slurry, precipitating monobasic aluminum sulfite from the filtrate at 110° C and 60 psig, a& decomposing the sulfite in the spent liq¬uor at 150° C and 55 psig to produce crude alumina. Purification of the crude alumina was accomplished using a modified Bayer process. Results from closed-circuit tests employing the sulfurous acid process showed that overall extraction of alumina from kaolin was 67 pct. Production of 1 ton of alumina would require 3.6 tons of calcined kaolin, 0.7 ton of sul¬fur dioxide, and 8.4 tons of water. After purification by a modified Bayer process, the alumina product contained the following; impurities, expressed in weight-percent: Fa203, 0.009; S, 3.6; Si02, 0.07; Ti02, 0.002; K20, 0.017; and P205, 0.03.

Jan 1, 1981