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Jan 6, 2007

By E. R. Maize

This report is the third of a series on convergence of roof and floor in coal mines and subsidence of surface that accompanies it. The first paper5/ dealt with extraction in a mechanized mine (Montour 10) having relatively short rib lines that retreat rapidly. The second dealt with extraction in a mine (Crucible) in which coal was loaded. by hand and in which the rib lines wore long and slow-moving. The present report deals with a mine (Gibson) in which conditions approximated those in the Crucible mine, except that the distance between room centers was considerably less and the pillars were narrower in consequence. Moreover, the average cover was less and the studies were made under the steep hillside of a stream valley compared with a gently rolling surface over the portions of the second mine studied. Gibson mine lies in the east-central hart of Washington County, Pa. , approximately midway between the Montour 10 end Crucible mines on a north-south line. A cooperative agreement covering the work was made with the Hillman Coal & Coke Co. through W. L. Affelder, vice president. This paper describes the methods used in the investigation, gives excerpts from the data obtained, and offers such generalizations as appear to be justified.

Jan 1, 1940

By G. L. Gates

The waters used to waterflood the Wilmington oilfield were studied by the Bureau of Mines, in cooperation with the city of Long Beach, Calif. Increases in the pressure of the injection wells indicated that they were being plugged by materials suspended in the waters. This study was made to identify the suspended materials, determine their origin, and find methods of preventing their formation. The suspended oil-coated materials were iron sulfide, barium sulfate, calcium carbonate, clay, and sand (or silica). Results indicated that the sulfide, which was as high as 90 milligrams per liter, was the product of sulfate-reducing bacteria. The injection of ocean water increased the sulfate content of the waters in the petroleum reservoirs from 3 to 250 milligrams per liter, thereby furnishing sulfate for growth of the bacteria. The waters were supersaturated with barium sulfate. Laboratory tests showed that sulfide could be removed from the waters by adding iron at a cost of 1 to 2 mills per barrel. The solubility of iron sulfide and calcium orthophosphate in the injection waters was also determined.

Jan 1, 1975

By Charles E. Whieldon

Data on the oilfields in Mahoning, Columbiana, Carroll, Jefferson, and Harrison Counties, Ohio, were collected from scattered sources and compiled to make the information readily available to operators who may be interested in conducting secondary-recovery operations in the area. General geology, oil production, oil-productive acreage, core data, reservoir calculations by townships, and miscellaneous data and reference material are presented.

Jan 1, 1965

By C. B. Manula

This report is volume 5 of an eleven-volume final report for a Grant completed by The Pennsylvania State University for the Bureau of Mines to develop a dynamic general purpose computer simulation model for underground coal mining. The simulator developed under the Grant has a wide range of possible applications in the design and evaluation of underground coal mining systems from the standpoints of health and safety, productivity, and mine environment. The Master Design Simulator consists of nine free-standing function-oriented subsystem models linked together into an integrated, comprehensive model of an entire mining system. The subsystems comprising the Master Design Simulator include geology and reserves, methane generation, roof support, subsidence, production, rail haulage, cost, water generation, and ventilation. This volume of the final report describes the Subsidence subsystem of the Master Design Simulator. This subsystem uses the finite element method to simulate ground movement caused by an advancing mining face in an underground coal mine. The model is structured around the concept that the ground mass is a layered media of different thicknesses and material properties. Gob areas are considered to be unfilled with broken rock at the beginning of mining. After mining starts, the gob areas are filled with broken material which provides resistance to the lowering of the overlying strata. The model is tied to the Geology and Reserves subsystem, but it can also operate as a free standing routine. A case study is presented illustrating the application of the model. A detailed user's manual, including a program listing, is included in the appendices.

Jan 1, 1974

By Robert L. Frantz

The performances of the three bituminous coal demonstration methane re¬covery boreholes, located in Greene County, Pennsylvania, are reviewed. Development of these vertical holes was largely underwritten by project funds. Reference is also made to an anthracite coal methane project in Luzerne County, Pennsylvania. This involved one vertical hole and was underwritten by a utility company. In addition, an exploratory drilling in the southern anthracite, which provided the project group with coal cores for methane gas analysis, is also cited. The technical and economical data that were gathered from the various methane projects are analyzed. Finally, the advantages and disadvantages of methane recovery by vertical boreholes are assessed.

Jan 1, 1978

By Richard H. Bares

The general or macroclimate of the study sites in western North Dakota is characterized by rapid and sometimes extreme daily and day-to-day temperature fluctuations, rainfall patterns which are erratic in spatial and temporal distribution and intensity, generally low relative humidity, plentiful sunshine, nearly continuous air movement, and a relatively short frost-free period. Of particular relevance to plant growth and productivity is the mosaic of microclimates: these microclimates are affected by landform (convex and concave surfaces); exposure; slope angle, length and aspect; soil color, texture and surface cover (litter), and vegetation cover. The most critical plant growth governing factor in this region is available water. It is determined principally by water input (precipitation) and water loss (evapotranspiration) which is increased by high temperatures, wind, and poor litter and vegetation cover. While spring and fall precipitation is generally gentle and soil-soaking summer rains frequently come in the form of intensive, soil-washing, localized convective thunderstorms of short duration. Due to the convective nature of these storms, summer rainfall is particularly affected by regional topography; southwest slopes and crests often receive more rainfall since these storms usually move in a northeasterly direction. The water loss due to runoff and consequent soil erosion arc major problems resulting from such "cloudbursts". Previous fall precipitation (September - October) when added to current seasonal precipitation (March - August) was found to be significantly correlated (r-.93) with plant production. Winter precipitation (snowfall) is relatively light as the prevailing weather is dominated by dry polar air masses from the north. The nearly continuous wind is responsible for removing snow from open exposures and depositing it in depressions and windbreaks. Although the winter precipitation is not a large component of the total annual precipitation, conservation of that which does occur would contribute to plant production during the following growing season. Generally clear skies over the region facilitate receipt of abundant sunshine at the earth's surface. While good for early season soil warming and plant photosynthesis, this abundant sunshine coupled with long days and nearly continuous wind is responsible for evapotranspiration exceeding precipitation by an average of six inches between June' and September. On a local (micro) scale, the water deficit is most severe on the southern exposures which receive the most direct (most effective) solar radiation and therefore are warmer than other exposures. On a broader scale, it was found that ambient temperature extremes were slightly but significantly greater in the town of Beulah in the Knife River Valley than at the upland test sites, This may have been due to the difference in topography and/or the "urban heat island" effect. It is known that air temperatures in large cities may be 2° to 4°C higher than that of the surrounding countryside. It is also well known that basins, depressions or valleys are sinks for cold air masses and are often subject to frosts not occurring on adjacent upland sites.

Jan 1, 1982

By R. Barany

This report contains the results of experimental work conducted by the Bureau of Mines to obtain the heats of formation at 298.15° K. of analcite, dehydrated analcite, lawsonite, anorthite, hexagonal anorthite, and leonhardite. Thermodynamic data for these minerals have applications in ceramics, extractive metallurgy, and particularly in geochemistry. Except for data on anorthite, no previous similar data existed. The present results will be a substantial aid in deriving the temperature-pressure-equilibrium relationships among these minerals. The heats of formation were determined by solution calorimetry, with hydrofluoric acid as the reaction medium. The results were expressed both in terms of the constituent oxides and in terms of the constituent elements. The heat of formation data were combined with related entropy values to obtain the free energies of formation at 298.15° K.

Jan 1, 1962

By Charles L. Kimbell

The year 1979 was a period of increased activity for the world's mineral industry, distinctly in contrast with 1978 when estimated world crude mineral output value declined slightly and most phases of the industry's activity were somewhat curtailed. In 1979, most major mineral commodities recorded significant gains in output, with a substantial number achieving new record highs; details on trade levels for 1979 were not available, but increases over those of 1978 were expected on the basis of partial data. Consumption of most commodities edged higher; in some cases the higher demand levels were met largely through draw-downs of stocks accumulated in recent years, while in other cases notable output increases were required to meet demand. Actually, 1978 was not a bad year for all elements of the mineral industry if changes in output levels of the various commodities are considered as a measure of performance. There were far more individual commodities registering production increases between 1977 and 1978 than registered declines, but some of those reported as declining were relatively major commodities (bauxite, aluminum, copper and zinc were notable), Moreover, the upturn in productive activity in 1978 was not matched by increases in profits. However, 1979 was unquestionably a year of renewed expansion efforts, although some commodity areas, most notably the steel industry component, were still experiencing difficulties.

Jan 1, 1981

By E. E. Harton

Bureau of Mines Information Circular 16, Bibliography of Investment and Operating Costs for Chemical and Petroleum Plants, was published in October 1949 as an aid in making estimates of investment and operating costs of processes for manufacturing synthetic liquid fuels. Development of such processes by the Bureau of Mines was authorized by Public Law 290, 78th Congress. This bibliography included refer¬ences to and abstracts of publications appearing from 1930 to September 1948 on all processes in general use in the petroleum refining and chemical industries. Publications in this field have been numerous since compilation of the above bibliography, and the present report was prepared to cover the field from September 1948 through June 1952.3/

Jan 1, 1955

By John J. Sammarco

The U.S. Bureau of Mines has developed a regulated, intrinsically safe, rechargeable power supply for portable electronic equipment for underground use. The regulated output is ideal for microprocessor power requirements and is suited for operation in hazardous environments. Two rechargeable, sealed batteries are contained within the power supply. Provisions are made to use an external source of power if these batteries fail. Provisions are also made to charge these internal batteries when needed. The circuit is composed of three main circuits: the main regulator circuit, the input protection circuit, and the output protection circuit. The main regulator circuit provides remote voltage sensing, current sensing, fault monitoring, and internal thermal protection. The input protection circuit checks for excessive input current and low battery conditions. The output protection circuit contains two overvoltage detection devices. Schematics, a parts list, and a calibration procedure are provided in this report to enable readers to fabricate the power supply.

Jan 1, 1989

By Max J. Spendlove

The secondary copper industry is comprised of numerous enterprises which collectively employ many of the recovery and refining processes now used in primary plants as well as many other processes that are unique to the industry. Effective methods are used for identifying and segregating all types of scrap according to widely accepted standard classifications. Segregated scrap and waste materials usually require some preliminary processing to remove both valuable and deleterious associated constituents. Smelting, melting, alloying, and pyrorefining are common methods used for producing secondary metal, but operating techniques usually differ from primary metal operations because of the difference in physical and chemical properties of the respective raw materials. Some copper scrap is converted to copper chemicals rather than to refined metals or alloys. Recovery efficiencies of all processes are reasonably high, and the quality of products meets rigid specifications.

Jan 1, 1961

By S. J. Aresco

The Bureau of Mines has been active in promoting the purchase of coal for Government use under specificetiona that define the requirements in terms of heating value of the coal, expressed in British thermal units, and the composition as shown by proximate analyses. To these, when required, are added the fusing temperature of ash and the free-swelling index. Under most of these specification contracts the bidders guarantee the quality of the coal, end that guaranteed by the successful bidder becomes the standard of his contract. The deliveries are sampled in accordance with instructions3/ issued by the Bureau; the samples are analyzed in the Bureau's laboratory to determine whether the coal is of the quality guaranteed by the contractor and, if it is not, a price adjustment is made. Analyses of the delivered coal and "tipple" samples (samples collected at mine tipples as coal is being loaded into railroad cars or trucks) provide valuable data for use in evaluating future bids. In addition, the continuous sampling of coal as delivered 1s a check on the practical results obtained in burning the coal.

Jan 1, 1953

By George W. Huseman, W. D. Mcmillan

"INTRODUCTION Feldspars represent one of the most abundant groups of minerals and constitute nearly Go percent of the material contained in the igneous rocks. They are grouped in a series of related aluminum silicates with varying amounts of potash, soda, and lime. .Approximately 85 percent of the feldspar produced in the United States is used as a flux in the production of glass, pottery, enamel and sanitary ware, brick, and tile. Notwithstanding the abundance of feldspar in the earth's crust, the only deposits that are worked to any extent are the pegmatites or coarsely crystalline dikes where natural segregation of the constituents facilitates recovery of the feldspar with a minimum of free quartz, mica, tourmaline, garnet, and other iron-bearing minerals that are detrimental in most ceramic industries.Although there are three glassplants and numerous other ceramic industries in Texas, all of the feldspar used in these plants is from other States. In the Llano region of central Texas, however, there are numerous coarse pegmatite dikes consisting primarily of feldspar and quartz in ratios up to 3 to 1. One of the more important of these dikes is the Badu Hill deposit in Llano County, Tex., which was first described by Carl Chelf 4/ in 1942. Following an examination of the deposit by W. D. McMillan, engineer in charge of the Texas field office of the Bureau of Mines, in January 1946, a proposal was made to investigate the deposit by core drilling in cooperation with the Department of Ceramic Engineering, University of Texas. This report presents the results of the cooperative investigation, which was begun April 24, 1946, and completed May 17, 1946."

Jul 1, 1947

By C. E. Rork

This paper discusses various mechanical improvements that have been gradually incorporated in the copper-willing plants of the Southwest daring the past 14 years, power plants for concentrators, use of large-size units of equipment, and the effect of plant capacities on costs. The improvements in mechanical equipment and plant design have contributed in the reduction of operating costs; in some instances a saving in the capital cost per ton of daily capacity milled has resulted.

Jan 1, 1935

Two coal seams were selected and the conceptual designs were based on the geological and physical conditions typical of these seams. As a result of the screening process presented below, the two coal seams selected were the Lower Kittanning Seam in central Cambria County, Pennsylvania and the Pittsburgh Seam in northwestern West Virginia and southwestern Pennsylvania. SELECTION PROCESS FIRST SCREENING OF LONGWALL OPERATIONS The list of longwall operations prepared in Phase I and included in the Phase I report, was used as the basis for a first screening. From this list it was determined which longwall operations were not in the Appalachian coal fields and not in a coal seam of the thickness range of 42 to 72 inches. The first screening eliminated 30 of the listed operations, leaving 48.

Jan 1, 1976

By Thomas Fraser

WHEN the Bureau of Mines initiated the program of large-scale research and development in the field of synthetic liquid fuels authorized in the Synthetic Liquid Fuels Act of April 5, 1044, the Coal Preparation Section was assigned the task of obtaining data on the preparation characteristics of the coal in large reserves that might be adaptable to use in this new industry. It is natural that, as the rapidly developing general research program brought about new concepts of raw-material quality, preferred geographical location, and the like, the orientation of coal-preparation investigations should have undergone some change. The first major assignment was the sampling and testing of a series of typical American coals deemed to he suitable for hydrogenation based on early research work conducted by the Bureau of Mines. This first series of tests has been completed and is reported in this paper.

Jan 1, 1950

By R. H. Grau, R. Krog

The National Institute for Occupational Safety and Health (NIOSH) has conducted research to improve the ventilation of large-opening mines. The research has demonstrated that the ventilation of large-opening mines improves significantly by including ventilation requirements in the mine planning process and implementing somepractical techniques during mining. Planning the location of long pillars to reduce the number of crosscuts between intake airways and return airways, positioning auxiliary fans in their proper locations, and establishing ventilation stoppings with minimal leakage all significantly improve the ventilation of large-opening mines. Mine operators that adopt these techniques in the mine ventilation plan will reduce mineworkers’ exposure to airborne contaminants.

By Leonard Obert

Between 1927 and 1957, sodium borate minerals were mined by underground methods in the Kramer District, Kern County, Calif. In 1957, surface mining methods were initiated, and during the next two or more decades it is probable that most of the production from the district will be obtained from open pits. However, part of this borate deposit is sufficiently deep that surface mining may not be economical and, hence, at some future date underground methods may again be employed. This report was prepared to document the underground mining methods employed in the district before 1957. The general geology of the district and the detailed geology of each of four mine sites are presented, together with a mineral and mechanical description of the ore and enveloping rock. The report also describes the stoping, extraction, pillar support, methods of artificial support, and other factors that affect the structural characteristics of these mines.

Jan 1, 1962

By Thomas J. Peters

In 1984, at the request of the Bureau of Land Management, the Bureau of Mines studied 7,000 acres of the 9,240-acre Little Blitzen Gorge Wilderness Study Area in Harney County, OR, to evaluate its mineral resources. The study area is dominated by a 1,500-ft-deep canyon that was carved by Pleistocene glaciers in gently westward-dipping homoclinal flows of Miocene Steens Basalt. The Bureau reviewed pertinent literature and county mining records During the field investigations, 18 rock samples were collected from basalt dikes, breccia, fractured or porphyritic flows, and 20 alluvial samples from gravel accumulations. Mercury anomalies from sampling by the Oregon Department of Geology and Mineral Industries could not be verified. The mercury might have originated -From the Pike Creek Formation, a known mercury-producing unit that may extend into the study area beneath the Steens Basalt. Any epithermal deposit at depth would be expensive to explore and develop.

Jan 1, 1986