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By Jack Kadlecik

This final technical report describes the concept feasibility study, testing, design and development effort which went into. The quick opening enclosure access cover and flame path tolerance checking system. A detailed definition of the explosion-proof multiple start threads is shown for two (2) sized electrical enclosures.

Jan 1, 1972

By R. V. Petrella

The flash induced combustion of Sewell and Pittsburgh coals was studied in air and in oxygen. The primary decomposition and combustion processes occur within the first 300 ~sec in oxygen and slightly later in air. Strong absorption spectra of CN and OH are indicative of the decomposition and combustion processes, respectively. Kinetic spectroscopy and combustion product analyses indicate that only about 35% of the coal dust is consumed in the explosive combustion which takes place in several (1-5) distinct but similar steps. The combustion-modifying effects of (NH4)2HP04, NH4H2P04, KHC03 and Rock Dust were studied in the 1-20 wt % range in coal dust flash com-busted in air and oxygen. The study reported herein shows Rock Dust to be the most efficient coal combustion inhibitor. KHC03 is the least effective agent, with the phosphate salts showing marginal effectiveness.

Jan 1, 1976

The contract objective was to evaluate sources of airborne quartz and research control methods that would assist underground mine operators in complying with respirable dust standards which have been reduced because of quartz in the dust exceeding five percent. The work involved: Phase I -evaluate sources of quartz dust at the roof bolter work location; Phase II -evaluate the relationship between the quartz content of the coal and adjoining rock strata and quartz exposure at the roof bolter and continuous miner locations Phase III -conduct laboratory tests to determine performance parameters for roof bolter dust collector systems. The underground surveys for Phases I and II determined: (1) the continuous miner typically is the greatest source of quartz exposure for the miner and roof bolter operators when single-split ventilation is utilized, (2) a statistically significant relationship be­tween quartz content in face material and operator exposure was not determined and data suggested mining equipment and procedures may be more critical. The Phase III lab tests indicated the use of dust hog-type bits, filter cartridges, maximized collector airflow, and reduced bit rpm should be utilized to minimize dust liberation at the roof bolter.

Jan 1, 1985

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 Z. Zborovszky

The feasibility of using the nucleation properties of combustion generated particulates for the identification of their sources was investigated, using the Cloud Condensation Nuclei (CCN) Spectrometer. The Investigated materials included coal, wood, belt materials, electrical insulation, brattice cloth, and diesel exhaust. The materials were heated In an oven using filtered air flow, and their time, temperature, and the critical supersaturation spectrum of condensation nuclei (also referred to as the CCN spectrum) produced by the combusting material were recorded. Some data was obtained on a typical metal-mine background containing blasting products. The data was processed and analyzed In an attempt to specify parameters and limits that would allow the identification of the combustion sources. It appears that under controlled test conditions It Is possible to Identify the source on the basis of data derived from the CCN spectrum. More general use of the Idea for fire detection under uncontrolled practical circumstances in an actual mining environment does have potential but would require further research.

Jan 1, 1978

By Lloyd H. Banning

Crucible-smelting tests at the Northwest. Electrodevelopment Laboratory and a pilot-plant test on electric smelting of western phosphate rock for the Westvaco Chlorine Products by the Tennessee Valley Authority indicated that the small vanadium content of the rock is concentrated in the ferrophosphorus by-product of Phosphorus smelting. This research is concerned' mainly with recovering vanadium and phosphorus froth the ferrophosphorus produced from western phosphate rock. Exploratory tests were made of several methods of treating vanadiferous ferrophosphorus. Attempts to separate vanadium as a carbide dross by saturating molten ferrophosphorus with carbon were unsuccessful. Volatilization of phosphorus from ferrophosphorus was accomplished to some extent, both with and without addition of sulfur in several forms, but elimination of phosphorus was not complete. Brief testing in a small experimental converter on oxidation of vanadium and phosphorus; into a slag by blowing with air showed promise. A method that comprised fusing vanadiferous ferrophosphorus mixed with soda ash under oxidizing conditions gave encouraging results and was tested beyond the preliminary stage. A slag product of the fusion contained most of the phosphorus and vanadium as water-soluble sodium phosphate and. virtually water-insoluble sodium vanadate. After leaching the sodium phosphate froth the slag, the leach residue was reroasted with soda ash and salt. This roasted product was leached again with water to extract the vanadium.

Jan 1, 1951

By Lloyd Williams

1. The investigation shows that the Poplar Creek and Big Mary beds contain the largest known recoverable reserves of coal in Morgan County, Tenn. The Poplar Creek bed has been the most productive. 2. Known measured and indicated reserves of coal, based on a minimum bed thickness of 14 inches and on 1,800 short tons per acre-foot of coal in place, are estimated to be 96 million tons, as of January 1, 1954. Of this total, 59 million tons is in beds 28 inches and more thick. Areas in each bed were omitted from the estimate because available data relative to the bed characteristics were too meager to make an estimate that conforms with the definitions of measured and indicated coal adopted for this study. Should future drilling or development prove reserves in these areas, such reserves should be added to the total estimated reserves.

Jan 1, 1956

By F. J. Prokoski

The COALSTAR Project, which operated from November 1981 to December 1982, was a research and development project aimed at providing a reliable and inexpensive means of monitoring various waste site conditions via the GOES satellite system. The GOES system provides data transfer from unattended isolated sites where neither power nor telephone lines exist. The reliability and resolution of the data received while using the satellite link were excellent; however, the site instrumentation gave considerable trouble. The disastrous failure of a large coal waste embankment in 1972 led the Bureau of Mines to undertake a comprehensive program to reduce the likelihood of such an occurence again. Part of this program involved the installation of instruments to monitor the stability of a specially-selected embankment operated by Armco Incorporated near Montcoal, West Virginia. Initially, the instruments were monitored by normal telephone lines and used normal commercial power from the local utility. The project described here was initiated to replace this monitoring system with an unmanned, solar-powered data collection system which transmitted data via satellite to a central computer facility. The satellite data network is the National Earth Satellite Service of the National Oceanic and Atmospheric Administration.

Jan 1, 1984

By Fred Leighton

The Bureau of Mines has developed rock noise source location techniques that may be used to obtain precise and practical source locations from micro-seismic field data. These techniques enable one to monitor all or any part of a rock structure and map progressive stress buildup or rock movement. Thus, the microseismic method of determining instability in rock structures is becoming an invaluable engineering tool for the mining or civil engineer engaged in rock excavation and construction.

Jan 1, 1970

By R. J. Gunderman

Redesigns of the operator compartments on a continuous miner and on a face haulage vehicle are described. The objective was to optimize the compartments within limitations of existing equipment and functional configurations. Both safety and production should be improved through more comfort for the operator and more natural placement of controls. Design guidelines supplied by the Bureau from a previous contract were used along with human factors analyses to determine requirements. Mock-ups were fabricated from layouts and used to refine design details. The new compartments were implemented and the machines evaluated underground. Comments and reactions to both machines were favorable.

Jan 1, 1978

By J. A. Kost

The objective of Contract J0295041 was to determine if the addition of a surfactant (wetting agent) to the water used for dust control in underground coal mines results in the reduction of airborne dust. Laboratory wettability tests, including the capillary rise test, a coal dust sinking test and zeta potential measurements, were used to select a coal seam/surfactant combination for in-mine testing. Four surfactants were selected for underground testing: Surfynol 465, Aerosol MA-80, DC-13, and Dustallay. The underground tests in the Lower Kittanning seam, Indiana County, PA, involved a Wilcox Mark 20 auger mining system, equipped with spray nozzles located on the cutting augers, Conflow venturi sprays, and a spray manifold. Respirable dust samples were provided by MSA Model G personal samplers and Simslin II instantaneous dust monitor; total airborne dust samples were provided by MSA Model G samplers with UNICO filter cassettes. Based on data obtained from 24 test periods surfactants, as compared to plain water, reduced the airborne respirable dust an average of 27 percent and total airborne dust an average of 36 percent.

Jan 1, 1980

By David A. Hill, James R. Wait

This report contains a summary of analytical research on electromagnetic methods of nondestructive testing of cylindrical conductors. The principal objective is to provide theoretical insight to the operation of electromagnetic sensing of the internal properties of wire ropes that are used extensively in mine hoists. An overall review of past work is also included.

By Terry J. Close

The Welcome Creek Wilderness has small, dispersed gold placers. Pockets in the 25.5 million yd3 (19.5 million m3) of alluvium along Welcome and Rock Creeks have as much as $5.61 gold/yd3 ($7.34/m3) at $500/troy oz ($16.08/g). All the alluvium averages 20.1 cents gold/yd3 (26.3 cents/m3). Because of the low average gold content large-scale placer mining would not be economically feasible. Small-scale selective pocket mining, however, may be profitable. The alluvium along the streams in the Wilderness has little apparent potential for production of sand, gravel, or stone because alternate sources are closer to markets. The four lode prospects known within the Wilderness appear to have low mineral potential. No oil, gas, uranium, or geothermal energy sources are known to be present.

Jan 1, 1982

By A. Monomakhoff

If a conductor traversed by an electric current is broken, a conduction forms in the air between the two broken ends of the wire. This conduction manifests itself in an initial phase by an electric spark and, in a second phase, by an arc if the the circuit continues to supply sufficient power. This arc goes out when the distance between the two ends of the conductor becomes sufficiently large. If the break occurs in an explosive atmosphere, the energy contributed by the arc can cause an explosion. To avoid such accidents, electric circuits that may be utilized in hazardous atmospheres can be made "intrinsically safe". The investigation which we conducted is part of a research project on the intrinsic safety of arcs of high intensity but short duration, in the case of resistive circuits. We developed an electronic system which makes it possible to limit the duration of an arc at the level of the break of a conductor traversed by a current with a possible maximum intensity of 80 amperes. This experimental device for monitoring and measuring the parameters of the arc has shown that arcs of high intensity but with a duration limited to a few microseconds do not ignite an explosive methane-air mixture.

Jan 1, 1975

By J. H. Jones

The original term of grant No. 1115174 was September 1980 through December 1983. An extended progress report, covering this time period, was forwarded to the Bureau of Hines in January 1984. The principal investigators were given a no-cost extension of their grant to cover the period January through December 1984. The report which follows covers this latter time period only.

Jan 1, 1985

By George A. Savanick

The objective of this research is to develop a method for measuring the tensile strength at the interface between minerals in rock. These measurements reflect the strength of the attractive forces operating at crystalline interfaces in rock. Since these forces act in opposition to the forces set up in various rock fragmentation processes, measuring their strength may help in designing more efficient methods of rock fragmentation. The method developed for measuring the strength of intergranular adhesion in rock involves separating a bicrystal from the rock and determining the tensile strength at its solid-solid interface. This technique has been successfully applied to the study of quartz-feldspar interfaces separated from massive pegmatites, graphic granite, and the Rockville granite, yielding average tensile strengths of 5.86, 8.62, and 10.65 meganewtons per meter squared (MN/m2) (850, 1,250, and 1,524 psi, respectively). The data this technique provides indicate that the members of these bicrystals are strongly adherent. Examirtation of bicrystals broken at the crystalline interfaces indicates that the bonds responsible for this adhesion operate over only a portion of the interfacial area. This work conclusively demonstrates that tensile strength tests can be conducted on small selected areas; for example, grain boundaries in rock. The small-scale zones of strength or weakness determined in this way can be related to the overall strength of the rock.

Jan 1, 1972

The objective of this condensed handbook is to provide the inspector with guidance for recognizing hazards from inhalation contaminants in above ground work areas of underground and surface coal mining and processing facilities and evaluating these hazards by collecting samples or making field determinations and interpreting the analytical results. It will be carried with the inspectors during their surveys. The complete handbook should be left in their offices except for Appendix II which lists the compositions of products found in previous surveys. There are several portions of the condensed handbook which should prove most useful to the inspectors. The names and locations of these portions are listed below: Procedure for an Industrial Hygiene Survey (Page 2-1) Survey Check List (Page 2-3) Rules for Determining if Sampling is Required (Page 2-2) List of Most Frequently Encountered Contaminants (Page 2-5) List of Candidate Contaminants and their Sampling Conditions (Page 2-A) Interpretation of Results (Page 3-8) For obtaining information not available from the above mentioned portions of the handbook, the inspector is directed to the Table of Contents, and the Glossary of Terms (Appendix I).

Jan 1, 1975

By Fredrick L. Johnson

The Bureau of Mines, under Congressional mandate, conducted a mineral survey on the Park Range WSA (Wilderness Study Area) in 1984 and 1985. The WSA, located about midway between Tonopah and Ely, encompasses 47,268 acres. No mineral resources were delineated, nor were workings found, during the investigation. There has been, however, exploration in and near the north end of the study area. ASARCO is actively exploring a block of 41 claims for hot-spring type, low-grade, large-tonnage gold deposits. Their claim block is almost entirely in the study area. The Morey mining district, 7 miles southwest of the study area, produced silver and lesser amounts of gold and lead sporadically from the mid-1860's through the mid-1960's. The WSA is underlain by Tertiary rhyolitic and latitic volcanic rocks and by Paleozoic sedimentary rocks. The Paleozoic rocks have been faulted, silicified, brecciated, and hydrothermally altered, and have anomalous concentrations of precious metals and pathfinder elements. Additional exploration in the north part of the Park Range WSA may lead to delineation of gold resources.

Jan 1, 1986

By Clayton M. Rumsey

The U.S. Bureau of Mines conducted a mineral resource survey of the Cinder Cones Wilderness Study Area (WSA) (CDCA-239), 10 miles east of Baker, CA, in 1983. The 44,299-acre WSA is underlain by Precambrian granite gneiss, Upper Cretaceous or lower Tertiary Teutonia quartz monzonite, and Quaternary basalt flows and alluvium. This mineral survey included an examination of two volcanic cinder mines, five lode prospects, two volcanic cinder prospects, and reconnaissance sampling in and near the WSA. The seven prospects are in the WSA; the two volcanic cinder mines are adjacent. No mines are in the WSA. In 1981, there were 61 placer and 3 lode mining claims in the WSA. Sample results from two prospects within the WSA contained significant gold and silver values; however, the mineralized rock is of limited extent and no resources were apparent. Alluvial samples taken throughout the WSA contained only traces of gold. Two volcanic cinder cones within the WSA contain an estimated 30 million tons of cinders. There are sufficient cinders outside the WSA to satisfy demand in the foreseeable future. Stone, sand, and gravel deposits are not resources because similar material is closer to markets. No evidence of energy minerals or geothermal resources was found.

Jan 1, 1985

By William C. Hood

A leaching column technique that produces effluent similar in quality to coal mine drainage in the Eastern Interior Basin has been developed. The columns are charged with 1000 grams of crushed overburden and cycled through the leaching process once a week for twelve weeks. Inter-relationships among the important chemical constituents are very similar to those present in actual mine drainage waters, but the overall concentrations of ion are more dilute in the leachates. Multiplying the leachate concentrations by a factor of 4.5 gives values similar to mine waters. Available data suggests that each of the leaching cycles represents about three years of natural weathering, so that the leaching technique can predict the evolution of the mire drainage water over a time span of nearly 40 years. Use of the leaching technique with drill core samples should provide a method of approximating mine drainage quality in advance of mining and should be quite useful in identifying potentially toxic units in the overburden. However, the results should he considered to be a 'worst case' situation because the technique' does not consider the effects of reclamation.

Jan 1, 1984