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By D. O. Hamiltion

The ISMS program provided for the development and demonstration of equipment modifications in both conventional and continuous coal mining systems. This report describes activities during the demonstration of the conventional equipment and includes machine performance, results of data gathering, system evaluation, and recommendations for implementing improvements.

Jan 1, 1976

By Michael J. Beus

This Bureau of Mines report describes field investigations conducted in the Coeur d'Alene mining district of Idaho to obtain data on rock stress and physical properties. The resulting information has been utilized as input to detailed finite-element analyses to establish structural design criteria for deep-vein mine shafts. Measurement techniques include the Council for Scientific and Industrial Research biaxial and triaxial strain cells, the U.S. Geological Survey solid-inclusion probe, and the Colorado School of Mines dilatometer. Physical property testing was conducted in the laboratory on core obtained from each test site. Limited in situ physical property tests were also conducted. Reason-able success was obtained with the CSIR equipment, which was considered the most suitable for stress measurement in the study area. Test sites ranged in depth from 1,200 to 7,700 feet and are described in detail. The stress data were reduced by least-squares linear regression techniques to enable prediction of vertical and horizontal stresses to 7,500 feet. Ratios between the horizontal stresses as utilized for shaft design varied considerably, and a hydrostatic condition is the exception, based on Bureau measurements. Physical properties also varied widely, due to the complex geologic structure. Analyses of the data in terms of the tectonic history of the area show reasonable correlation. Data from previous rock mechanics investigations from the Coeur d'Alene district were also compiled and presented as part of this report to justify any generalizations regarding stress conditions and physical properties of the district as a whole.

Jan 1, 1980

The XVIth International Conference on Coal Mine Safety Research was divided into eight half-day technical sessions. In accord with the established practice of these conferences, at each session, presentation of the papers was followed by a discussion period. Questions and comments submitted in writing to the session chairman were answered or discussed by the authors of the relevant papers or by their representatives. These discussions were tape-recorded in the original language of the speaker and subsequently translated into English when necessary. Questions to which no answer was available at the time and a few comments that exceeded the scope of the session have been omitted.

Jan 1, 1975

[CONTENTS COUNTY NO. OF MINES MINE INDEX PAGE]

Jan 1, 1980

By Jon K. Ahlness

The Bureau of Mines conducted laboratory and field experiments to determine tne amount of permeability reduction in uranium sandstone after its exposure to different drilling fluids. Seven polymer and two bentonite fluids were laboratory-tested in their clean condition, and six polymer fluids were tested with simulated drill cuttings added. Sandstone cores cut from samples collected at an open pit uranium mine were the test medium. The clean fluid that resulted in the least permeability reduction was an hydroxyethyl cellulose polymer fluid. The greatest permeability reduction of the clean polymers came from a shale-inhibiting synthetic polymer. Six polymer fluids were tested with simu-lated drill cuttings added to represent field use. The least permeability reduction was obtained from a multipolymer blend fluid. A field experiment was performed to compare how two polymer fluids affect formation permeability when used for drilling in situ uranium leaching wells. For this test, the polymer fluid with the best laboratory results (multipolymer blend) was compared with a commonly used polymer fluid (guar gum) that gave poorer laboratory results. When fluid injection rates for the four wells drilled with the guar gum were compared with those for the four drilled with the multipolymer blend, no statistically significant difference was found.

Jan 1, 1984

By George A. Morgan

The 53 countries that constituted Africa in 1989 accounted for a significant portion of total world output of a number of mineral commodities. Among the most significant minerals to be produced in Africa were andalusite, antimony, asbestos, bauxite, chromite, coal, cobalt, copper, diamond, fluorspar, gold, lithium minerals, manganese, phosphate, platinum-group metals, and the titanium minerals-ilmenite and rutile, vanadium, vermiculite, and zircon. Despite the underdevelopment of much of Africa, mineral raw materials played a very important part of the national economies of many of its countries. In terms of percent-age of export earnings, minerals accounted for more than 90% in some cases. In several countries with agrarian economies and little economic diversification such as Angola and Guinea, a single mining operation could represent an important source of foreign exchange. These latter operations tended to be the more easily mined surface deposits of diamond, gem stones, and precious metals. Mineral commodities for which Africa had a high percentage of world output were bauxite, 16%; chromite, 44.5%; cobalt, 76.5%; copper, 13.9%; diamond, 50.7%; gold, 32.9%; manganese, 27.1 %; phosphate, 22.1 %; platinum-group metals, 48%; uranium, 29.2%; vanadium, 54%; and vermiculite, 41 %. Several of these, chromite, cobalt, diamond, and manganese, were not produced in the United States.

Jan 1, 1992

By Charles L. Kimbell

Virtually every available measure of total world mineral industry activity demonstrated that 1982 was little, if any, better for the industry than 1981 had been. Levels of production, trade, and consumption for virtually every major commodity declined; unit prices for most commodities fell, particularly in terms of constant dollars, and as a result of cutbacks in output and lower prices, capital available for investment within the industry was reduced. These conditions, coupled with the existence of considerable idle capacity, tended to retard investment, although there was an upturn in U.S. oil industry investment overseas. Despite the overall depressed situation of the world's mineral industry, there were indications of possible improvements in market economy countries near yearend, as output of some materials increased marginally and as prices for some mineral commodities reversed their downward trends. The downturns in total world mineral industry activity were not universal from the viewpoint of individual countries. Indeed, output of a number of commodities increased in centrally planned economy countries, and these gains were insufficient to offset declines in market economy countries, thereby sharply altering the proportion of total world output accounted for by each of these two groups of countries. There was a similar shift in consumption on a percentage basis.

Jan 1, 1984

By G. Stecklein

This report summarizes the results of research into the areas of the fragmentation and entrainment of Airborne Respirable Dust (ARD). The objectives of this program were four-fold: first, to review the present state of knowledge regarding ARD; second, to expand this state of knowledge through the identification of hypothetical microscopic mechanisms by which the coal is fragmented and the dust becomes entrained; third, to specify the informational requirements to verify or nullify these hypotheses; and fourth, to relate experimental techniques that will produce that required information. Additionally, insights are provided regarding potential methods of extraction and/or treatment which may reduce the concentration of ARD.

Jan 1, 1982

By H. W. Kilau

The U.S. Bureau of Mines is evaluating water spray additives for the purpose of improving respirable dust control during coal mining operations, with particular emphasis on the longwall shearer. Recent field tests of surfactant-polymer reagents at two production longwall operations have shown favorable respirable dust reductions compared with water sprays containing no additive. Gravimetric dust samples obtained by a technician downwind of the shearer while following or preceding the machine showed dust reductions in the range of about 40% to 60% for some of the reagent formulations compared with using water alone. Three polymers were tested: two polyethylene oxide compounds of different molecular weight and hydroxypropyl methylcellulose (HPMC). All were effective for dust reduction, and two were cost effective when used in combination with sodium di(2-ethylhexyl) sulfosuccinate surfactant. How-ever, the use of these reagents requires the longwall operator to be more aware of headgate dust control. Experimental evidence indicates that dust captured by reagent-treated sprays at the shearer can be reemitted in the headgate area if stagcloader-crusher sprays and other dust controls are inadequate.

Jan 1, 2010

By Frederick C. Trutt

Research performed on arcing faults and their interactions with electrical insulating materials within coal-mine power system enclosures are described. This work was performed at The Pennsylvania State University from December 1, 1976 through August 31, 1978. The thrust of this research has been divided into several primary areas. These include the development of a theoretical procedure for computation of three-phase and line-to-line arcing fault currents as a function of time, formulation of arc and tracking models so that arc voltages and energies may be computed, development of a simulation for pressure and temperature rises when a fault interacts with an electrical insulating material within an enclosure, experimental evaluation of electrical insulating materials in terms of their tendency to support and maintain an arc as well as their potential contribution to enclosure pressure rises, and integration of the above research areas to form overall procedures for theoretical and experimental evaluation. During the course of this research, consideration has been given to the possible effects? of an internal methane-air explosion within an enclosure as well as the potential influence of utilization-voltage-level, conductor spacings, and enclosure venting. Conclusions and recommendations address potential means for protection against enclosure failure, internal design considerations, and low-power testing procedures which might be used to evaluate insulating materials to be utilized within an enclosure.

Jan 1, 1978

By D. A. Larson

The Bureau of Mines conducted research to develop preliminary engineering data necessary if the cobalt-rich manganese crusts that occur in the Exclusive Economic Zone (EEZ) of the Hawaiian Archipelago are to be mined. The research was divided into the following sections: (1) physical, mineralogical, and chemical descriptions; (2) mechanical property testing, such as compressive strength, tensile strength, and a rippability index; and (3) mechanical cutting characteristics, including average and peak cutter forces, the specific energy, and cuttings size distribution. Section 1 utilized microscope, X-ray powder diffractometer, and electron microprobe analyses. Section 2 utilized standard mechanical property testing techniques. Section 3 utilized a converted planer mill with full-size coal cutters to fragment the crust and substrate samples. The manganese crust samples were mainly manganese and iron oxides and hydroxides with an average cobalt content of 1 pct and had a nucleus or substrate of rock or sediment. The significant results shown by the mechanical property and cutting tests are that the crust and all but two types of substrates (basalt and trachyte) are weak materials and easily cut with standard drag cutters. The crusts are generally comparable to medium hard coal in strength and in their resistance to cutting.

Jan 1, 1987

By Richard C. Barth

Fourteen field plots were established at active coal mines in the Northern Great Plains. A wedge was cut into spoil and backfilled with soil; soil depth ranged from 0 to 152 cm over a linear distance of 15 m. Perennial grasses were planted in each plot, and production was measured from 1978 to 1981. Based on spoil traits and biomass response patterns, plots were grouped into four types. Spoil for Type I plots was near neutral, slightly saline, nonsodic, and clay loam in texture. Perennial grasses reached maximum production with approximately 50 cm of soil depth. Spoil for Type II plots was characterized as sodic and fine textured; soil-depth requirements averaged 83 cm for maximum production. Spoil for Type III plots was characterized as strongly acid, and production increased throughout the soil depth range tested. Spoil for Type IV plots was similar to soil in chemical and physical traits; there was no production response to soil depth. Soil depth requirements were also dependent upon precipitation and species. In general, soil-depth requirements decreased in dry years and with use of introduced species. An appendix contains data evaluations on an individual plot basis.

Jan 1, 1982

The original work statement of this contract was entitles: 'A Accident Analysis Model for Use in Underground Coal Mines.' The contract was scheduled for a duration of 26 months and was to be in three phases: Phase I - Model Development, Phase II - Application of the Model, and Phase III - Installation, Monitoring and Evaluation of the Model. Alter three months in Phase I, it became apparent that much of the needed data for the model was nut available and could not be made available within the original study schedule. Proceeding as plumed would have resulted in a model of limited utility. Personnel from Theodore Barry and Associates and the Bureau discussed the problem in detail and mutually decided to utilize the majority of remaining funds to assist the Bureau in solving these data problems and develop a stronger ongoing capability for safety analysis within the Bureau. Both tie contractor and the bureau officials involved believed that this decision greatly enhanced the Bureau's ability to develop future accident prediction models, whose rigor would greatly exceed what was currently possible.

Jan 1, 1972

By Oliver C. Ralston, and others

"INTRODUCTION Investigations of the Nonmetals Division are now conducted at College Park, Md.; Tuscaloosa. Ala.; Seattle, Wash.; and. Norris, Tenn. The last of these was acquired, this year by arrangement with the Tennessee Valley Authority and is engaged in electrothermel research, using power generated by the T.V.A. and. raw materials from that region. In general, the work of the division is concerned with dressing nonmetallic minerals end utilizing the products there-from. Coal, salts, and waters are investigated, and the suitability of apparatus and equipment is studied.As the Metallurgical. Division of the Bureau of Mines makes routine tests of certain nonmetallic ores under prescribed conditions for the public if they are of general interest, the published reports of that division should be read and thus, with the reports of tile Nonmetals Division, the whole field may be covered."

Oct 1, 1939

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 James R. Boyle

The value of mineral production increased 6.2% in 1976. With the exception of coal, practically all commodities registered an increase in production and value; most had an increase in unit value. Total value exceeded $1 billion for the first time. The increase in nearly all nonmetallic mineral production was a complete reversal of the 1975 experience. Alabama led the Nation in the production of crushed marble and was second in bauxite and scrap mica, third in oystershell, third in kaolin, and fifth in dimension limes-tone and dimension marble. International Trade.-The international trade passing through the Mobile customs district was valued at $2,524 minion in fiscal year 1976, up 20% from that of the previous year. Of the total value of trade passing through the district, 52% of the value of experts and 89% of the value of imports were handled through the port at Mobile. The major export Commodity was coal through McDuffie Coal Terminal which amounted to nearly 2.9 million tons, up from 2.4 million tons in 1975. Coal exports were to Japan, Italy, Turkey, the United Kingdom, and Brazil. Other exports were cement (114,000 tons) and [ ]

Jan 1, 1979

By R. L. Thorne

The Snettisham Peninsula, 30 miles southeast of Juneau, Alaska, was studied by the Bureau of Hines to obtain basic information about the size, grade, and metallurgical characteristics of a large basic intrusive containing titaniferous magnetite. The investigation, which was part of a continuing program to determine the potential reserves of iron and titanium ores in Alaska, included transit and magnetometer surveys, followed by diamond core drilling and metallurgical testing. The magnetic attraction of a part of the Snettisharn Peninsula is noted on early navigational charts prepared by the Coast and Geodetic Survey. Reconnaissance examinations by the Geological Survey and a preliminary dip needle survey by the Territorial Department of Mines indicated the general nature of the basic intrusive, but little was known as to the grade and extent of the magnetite mineralization. The detailed survey by the Bureau of Mines proved an area of approximately 390 acres in which generally high magnetic anomalies with exceptionally high localized anomalies occur. Subsequent drilling across B representative section of the deposit yielded core samples, which assayed from 11 percent to over 45 percent total iron. A large sample of core composited to represent the drilled portion of the de-posit assayed 18.9 percent Fe, 2.6 percent Ti02, and 0.29 percent S, 0.32 percent P, and 0.05 percent v.

Jan 1, 1956

By A. H. WHITE, PERRY BARKER

In a consideration of the various means whereby more economical and more efficient use may be made of the fuels in the United States, the possibility of obtaining for the production of illuminating gas other and cheaper fuels than the Pennsylvania coals demands attention. For the Government, as well as for private corporations and the householder, there can be no more economical and efficient way of using some coals than through the medium of illuminating gas. In the stove, gas reduces the labor cost of heat production and lessens the drudgery of the kitchen; burned in the Welsbach mantle, it is an excellent and cheap illuminant. In addition, the coke that remains after the gas has been recovered furnishes a smokeless fuel that has about the same heating value as anthracite. Hence any investigations that will indicate how local coals through proper treatment may be substituted for the higher priced and rapidly vanishing Pennsylvania gas coals will bring about lower prices for both gas and coke and will also aid to conserve for use in metallurgical processes the coking coals of Pennsylvania and of ot,her States. The annual drain on the gas-coal resources of this country and the importance of the gas and coke industries are indicated by the fact that 8,390,129 tons of coal were carbonized in retorts in the United States in 1909. The resulting salable products from by-product ovens were 15,791,220,000 cubic feet of coal gas, 6,254,644 tons of coke, and 60,126,000 gallons of tar. The total value of all by-products was about $28,508,637.

Jan 1, 1911

By Lon A. Williams

This report, authorized under Contract Number H0220065, Amendment Number Six, documents the results of an investigation of lighting system modifications and designs for working place illumination in high and low coal entries of underground coal mines. The portable and machine mounted system designs, both modified and prototype, represent a continuation of work performed under Contract Number H0111403, Amendment Number One. See the Final Technical Report dated May 26, 1972 for detailed information concerning this prior Contract. All modified and prototype systems met the performance requirements of Bureau of Mines Specification 2G, as proved by test. In addition, the systems met the requirement for illumination, as specified in the Contract and in the proposed standards which were generated in response to Public Law 91-173.

Jan 1, 1976

By J. P. Connell

The U.S. Bureau of Mines awarded a contract to Morrison-Knudsen, Inc., to evaluate the use of roadheaders in underground mining operations. Road-headers were found to be widely used in mines as construction support units, as development miners, and as stoping machines. However, road-headers were found to have mechanical and electrical problems, to suffer reduced productivity when integrated into the mining cycle, and to create dust problems. Also high capital costs and low utilization and avail-ability cause high amortization costs per ton. This report identifies the roadheader operating problems and offers suggestions for improved mechanical and electrical design as well as manufacturer and owner responsibilities for improved availability. The development of a complex integrated excavation and ground support sys tern is no t warranted until the roadheader itself is made much more reliable.

Jan 1, 1980