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By R. Blickensderfer

An impact wear testing machine was devised by the Bureau of Mines that simulates the repeated impact conditions encountered in large milling and grinding operations where breakage and spalling are problems. The apparatus provides data on materials that may help in the design of alloys with improved resistance to deformation, spalling, and breakage. The test blocks are 2 in thick by 6 in by 8 in. Impacts are produced by dropping 3-in-diam balls weighing 4 lb from a height of 10 ft. Tests were run until breakage occurred or to a total of 100,000 impacts. Four types of failures of the test block were observed: (1) cold flow of the bulk material by plastic deformation, (2) flaking of the surface in the impact region, (3) spalling of the block to form a crater in the region of impact, and (4) breakage of the test block into two or more major pieces. The effects of composition, heat treatment, microstructure, and hardness on types of failure are discussed.

Jan 1, 1983

By William A. Beck

Bauxite was discovered in the Springvale district in 1916. About 16, 000 tons was mined in the period 1916 to 1922, but no bauxite mining has been done since that time. The Bureau of Mines explored for bauxite in the district from September 5 to November 18, 1943. During the life of the project, the Bureau of Mines obtained mineral exploration agreements covering a total of 11,330 acres from 50 property owners. A total of 388 holes were drilled on five of these properties and 164 samples were taken and analyzed. The Springvale bauxite district includes an area of about 30 square miles in the northwestern part of Randolph County, Ga. The village of Springvale is in the west central part of the district, and Cuthbert is 8 miles southeast of it (fig. 1).

Jan 1, 1949

By M. C. Irani

The Bureau of Mines has designed and put into operation a fail-safe control system for use in underground coal mines equipped with methane drainage pipelines. This control system can detect certain unsafe conditions and respond by automatically shutting off the flow of methane from the degasification borehole to the drainage pipeline. Methane flow is shut off when the methane content in the return airways reaches a predetermined level (typically 1.5 pct), when the methane drainage pipeline is ruptured by roof fall, or when there is an electric power failure. The fail-safe control system was designed using commercially available components and a methane analyzer system previously developed by the Bureau. The fail-safe system consists of a unit that combines a shutoff valve and pneumatic valve actuator, and electronic and mechanical equipment designed to detect hazards and effect shutdown. The fail-safe control system was designed to meet regulatory requirements issued by the Mine Safety and Health Administration (MSHA), U.S. Department of Labor, and State regulatory bodies for the safe operation of underground methane pipelines used for mine degasification. MSHA has inspected and tested this system and permitted its use in two mines. The Bureau installed the fail-safe system in two working coal mines, where successful performance has been demonstrated.

Jan 1, 1979

By A. J. Kraemer

For a number of years the Bureau of Mines has been conducting an investigation of crude petroleum from producing fields in the United States and the Western Hemisphere and has published a series of reports on these fields. Analyses of crude-oil samples tom some oil fields of Louisiana are given in Bulletin 291.4/ Analyses of 26 representative crude oils from various producing formations of southern Louisiana are given in is report. These.samples are from 14 field's in 10 parishes in the southern part of the State, usually designated as the "Louisiana Gulf Coast area." ACKNOWLEDGMENTS Thanks are due the representatives of the various companies from whom samples were obtained for their cooperation and assistance in helping to secure representative samples. The samples were analyzed under the direction of E. C. Lane at the Bartlesville station of the Bureau of Mines.

Jan 1, 1934

By Gordon H. Dechman

This report presents the concept, design, and testing of a sonic velocity monitoring system for the early detection of slope failure in open pit mines. The heart of the system is a device for producing reproducible sonic signals in rock. Because changes in the velocity of sound through rock near the top of the pit wall are a measure of extent and rate of fracturing of the rock, velocity histories obtained from periodic, automatic sonic velocity surveys provide positive information about developing slope instability.

Jan 1, 1976

By D. G. Puglio

This Bureau of Mines study covers 25 underground mines that were active in the Upper and Lower Freeport and Lower Kittanning coalbeds in 1976. The coal ranges from low to medium volatile in rank; its primary use is for steam generation. Seven mines emit more than 100,000 cfd of methane gas; those mines are the deepest and largest producers. The methane gas content of three core samples of the Lower Kittanning coalbed was estimated by the direct method. A sample from a depth of 320 feet contained 0.5 cu cm of gas per gram, at 620 feet there was 0.8 cu cm of gas per gram, and at 1,060 feet there was 11 cu cm of gas per gram. These results suggest that methane control problems will be encountered in the future as deeper coal is mined.

Jan 1, 1979

By James J. Dowd

The investigation to evaluate the reserves of coking coal in the United States suitable for the manufacture of metallurgical coke is being made by the Bureau of Mines in three parts: (1) To estimate known (measured plus indicated) recoverable reserves of all coking coal; (2) to study the carbonizing properties of coals and coal blends not now widely used for metallurgical coke making; and (3) to upgrade marginal coals through effective preparation. This is the second7j of a series of reports giving the results of studies by counties under part (1) of the investigation. This report covers Indiana County, Pa., which comprises parts of the Smicksburg, Punxsutawney, Elders Ridge, Indiana, Barnesboro, Latrobe, New Florence, and Johnstown Quadrangles. (See fig. 1.) A base map for each bed in each Quadrangle was made to the scale 1 inch equals 1,200 feet. Maps of mines, locations of drill holes, bed and total coal thicknesses, and the outcrop of the bed were plotted on the maps. With all available data plotted, isopach lines were drawn to limit areas of known unmined reserves in beds 0 to 14 inches thick, 14 to 28 inches thick, 28 to 42 inches thick, and over 42 inches thick. These areas of coal reserves also were divided into "measured" and "indicated" categories. All areas in each thickness range and in each category, mined-out areas, areas excluded from the estimate, and areas outside of the outcrop were measured by planimeter on the base maps. Estimates of total reserves 14 inches and more thick and maps for individual beds were prepared from these data.

Jan 1, 1950

By Nicholas Kyriazi

A joint effort by the U.S. Bureau of Mines and the U.S. Mine Safety and Health Administration (MSHA) was undertaken to determine how well self-contained self-rescuers (SCSR's), deployed in accordance with Federal regulations (30 CFR 75.1714), survived the underground environment with regard to both impact damage and aging. This report presents findings regarding laboratory-tested SCSR's from 1982 through 1990. The SCSR's were tested on human subjects and on a breathing and metabolic simulator (BMS). These results indicate that most of the apparatus, if they pass their inspection criteria, perform as expected except for units with manufacturing defects or design deficiencies. However, when the apparatus are carried in and out of the mine daily and stored at the working section, they may suffer abuse. Physical signs of abuse, unless extremely obvious, are frequently not detected by the miners or mine operators. This poses a potential danger to a user in an emergency. Recommendations include improved training in inspection procedures.

Jan 1, 2010

By Charles Will Wright

The purpose of this paper is to present briefly certain preliminary results of the study of mining methods by the United States Bureau of Mines; to show the relative importance of each method in terms of tonnages mined and man-hours consumed; to give to the mining engineers and particularly to the young student of mining a better understanding of the principal mining methods; and to indicate changes now in progress and to present suggestions for improvements in the art of mining. Questions of mine development and details of underground practice such as drilling and blasting, loading, hauling, hoisting, ventilating, pay systems and mine management are omitted, as these have been or will be discussed in other bureau publications.

Jan 1, 1931

By M. P. Board

The U.S. Bureau of Mines, under a cooperative agreement with Hecla Mining Co., conducted a rock mechanics study at four widely spaced horizons in a deep mine shaft in northern Idaho. The objective of the project was to measure and analyze rock deformation and lining behavior during construction of a deep shaft in a high in situ stress field within an isotropic rock mass. Rock mass displacements were monitored with multiple-position borehole extensometers. Liner stress and strain were measured with concrete pressure cells and embedment strain gauges. This report discusses the general trends and magnitudes of data from the four test sites, and relates the data to a proposed anisotropic constitutive model for the rock mass. A design procedure is then outlined for specifications of liner thickness and support installation sequences for future shaft sinking.

Jan 1, 1989

By A. R. Elliott

"In addition to the usual interpretation that is placed on the words ""thief"" and ""thieves"", the petroleum industry also uses these words when referring to an instrument that is used for taking samples of oil from a tank or reservoir. It is an abbreviation of the term ""thief-tube"". It is desirable in sampling volumes of oil in tanks or reservoirs to obtain samples at different intervals below the surface of the fluid, because of the variation in the character of the oil at different depths. It is for this purpose that the ""thief"" is used.The subject of oil thieves is probably as old as the oil industry itself. Opinions as to which is the most practical instrument for thieving oil in tanks, to obtain a true average sample, differ wherever oil is produced and is analyzed. Every district, and even many of the companies within the district, will have different appliances for ""grabbing"" oil samples. It is interesting to note in passing that though the thief has an apparently insignificant part in the handling of oil, yet the results depending on it are of paramount importance practically every branch of the transportation, refining, and marketing of petroleum. Determinations, particularly dependent on a representative sample, are made by the centrifuge, laboratory distillation tests, and the hydrometer.The purpose of this article is to discuss conditions found in the California fields. Only a general description of types of thieves and the methods of using them will be given. However, it is believed sufficient data are given to enable the reader to form his own opinion as to which of the devices is most practicable under the prevailing conditions. Thieves of all types have their good points, speaking broadly, and it is possible to get good results with any of them, provided they are operated according to instructions and with due care. In work of this kind the advantages or disadvantages reside in the person operating the instrument rather than in the instrument used."

Apr 1, 1920

By Maria I. De Rosa

The U.S. Bureau of Mines performed experiments to determine if primary gas toxicities that evolve during the early (~300° C) and later (~.400° C) combustion stages of polyvinyl chloride and chlorinated brattices could be predicted by a smoke particle characteristic, which could be used as a simple and inexpensive test parameter. The experiments were conducted in an approximately 20-L furnace at set furnace temperatures of 2500 and 1,0000 C, for 14 min duration, with an airflow through the furnace of 10 L/min. The variables studied, as a function of time, were the hydrogen chloride (HCl) and carbon monoxide (CO) concentrations, sample and furnace temperatures, the sample mass weight loss, the average smoke particle diameter (dg and number concentration (no), and the product of the average smoke particle diameter and concentration (dgno)' Results show that the inverse of the smoke particle diameter-concentration (l/dgno) correlates directly with the primary gas toxicities evolved during both stages of combustion.

Jan 1, 1989

By R. G. Nelson

This report covers investigations of the Bureau of Mines for the period of June 15, 1952, to June 15, 1953, on a research project for the Materials Laboratory, Wright Patterson Air Force Base, Dayton, Ohio. The primary purpose of this investigation was to make high-purity chromium-base alloys having room-temperature ductility and high-temperature strength. The Nonferrous Metals Branch of the Bureau of Mines, Albany, Oreg., has, during the past 7 years, developed on a laboratory scale a hydrogen treatment method for making high-purity chromium that can be fabricated into thin sheet and wire. This material can be bent at room temperature. The object of this investigation was to use this material to develop improved chromium-rich alloys for high-temperature uses.

Jan 1, 1955

The use of highwall mining systems (Figure 1) has increased substantially in open-pit coal mines. It is used where overburden depth exceeds economical recovery. Highwall stability remains the major safety concern during highwall mining. The Mine Safety and Health Administration requires highwall mining operators to follow ground control plans that specify the pillar sizes necessary to prevent a pillar collapse that would threaten highwall stability.

Mar 1, 2006

By Donald E. Redmon

This Bureau of Mines report reviews injury experience in the nonmetallic mineral industries (except stone and coal) for 1966-67. For each of the years, 23 tables summarize disabling work injuries by department, source of injury, extent of disability, part of body injured, and nature of injury. Correlative information on employment, worktime, and operating activity is also presented.

Jan 1, 1973

By P. C. Good

To meet a growing need for thorium metal of high purity and amenability to fabrication, the Bureau of Mines devised a method for preparing thorium metal by the reduction of thorium tetrachloride. Thorium tetrachloride was prepared by chlorinating calcined thorium oxalate with carbon tetrachloride. The crude thorium tetrachloride, containing oxygen-bearing compounds, was purified by a double vacuum distillation at 800 to 900° C., and thorium metal was made in the form of a dense sponge by the reaction of metallic sodium or magnesium with thorium tetrachloride at 800° C. Vacuum arc melting was used to consolidate the sponge metal to ingot form for evaluation of its physical and chemical properties.

Jan 1, 1960

By Michael J. Magyar

The Federal Bureau of Mines has developed a hydrametallurgical method to recover aluminum, aluminum oxide, and fluxing salts from aluminum salt slags. The slag is leached with water at room temperature to produce a saturated brine slurry. Screening of the slurry yields an aluminum-rich fraction that can be returned to the dross furnace. The remaining slurry is vacuum filtered, yielding a clear brine solution and an aluminum oxide filter cake. Evaporation of the clear filtrate produces a high-purity fluxing salt for reuse in the dross furnace. Over 80 pct of the metallic aluminum is recovered in the aluminum-rich oversize fraction, while essentially all the fluxing salts are recovered by evaporation. This report contains the final results of an investigation on a process research unit scale, an economic evaluation of the method, and recommendations to further improve the process.

Jan 1, 1979

Exposure to airborne respirable crystalline silica dust can lead to silicosis, a debilitating lung disease. On surface coal mining and construction sites, blast hole drills are notorious sources of airborne respirable dust that may contain significant amounts of silica. The drill operator and drill helper usually receive the greatest silica exposure compared with other occupations. As a result, many drilling operations have been, and still are, on more stringent dust standards. Drilling through various rock formations naturally presents a strong potential for silica dust generation for several reasons. First, drilling is a pulverizing process that generates large amounts of very small dust particles. Second, the bailing air used to flush cuttings from the hole leaves the hole at a very high velocity and can be difficult to contain. Third, many fixed shrouds used to enclose the area beneath the drill deck have a significant amount of leakage due to 1) gaps between the shroud and ground created by raising/leveling the drill, 2) gaps in the corner seams, and 3) tom deck shrouds. CONTROLS A dry dust collection system is typically connected to the drill deck to collect dust as the bailing airflow transports the cuttings (and significant amounts of airborne respirable dust) out of the drill hole. Deck shrouds are installed in an attempt to enclose the volume around the drill steel and prevent dust escaping. However, most deck shrouds are rectangular and constructed of four separate pieces of rubber belting attached to the deck. Because of this design, there is usually a significant amount of dust escaping from the open seams as well as the open area between the shroud and the ground. This dust can be a significant source of silica exposure to drill operators as well as other personnel downwind of the drill.

By Margaret R. Egan

The Bureau of Mines subjected three commercially available brands of transformer fluid to a series of combustion studies. The experiments were conducted in the intermediate-scale fire tunnel, which was designed to simulate environmental conditions in underground mines. The work was divided into three phases. In phase one, the brands were compared for gas production, smoke characteristics, and combustion yields. In phase two, the production constants of transformer fluids and other fuels were compared for the rate of formation of gas and smoke as a function of fire size. In phase three, several diameters of liquid-pool fires were compared in terms of fire size and burning rate. These transformer fluid measurements will be added to the existing coal and wood data that can be used as a basis of comparison for future studies of other mine combustibles. Further research into the combustion product emissions from combustible materials found in underground mines will lead to improved and realistic fire detection and suppression systems,

Jan 1, 1986

By Nicholas Kyriazi, John P. Shubilla

A joint effort by the U.S. Bureau of Mines (USBM) and the US. Mine Safety and Health Administration (MSHA) was undertaken to determine how well self-contained self-rescuers (SCSR's), deployed in accordance with Federal regulations (30 CFR 75.1714), held up in the underground environment with regard to both physical damage and aging. This report presents findings regarding laboratory-tested SCSR's in the fourth phase of testing from 1989 to 1993. The SCSRYs were tested on human subjects and on a breathing and metabolic simulator (BMS). These results indicate that most of the apparatus, if they pass their inspection criteria, perform as expected except units with manufacturing defects. However, when the apparatus are carried in and out of the mine daily and stored at the working section, they may suffer abuse. Physical signs of abuse, unless extremely obvious, are frequently not detected by the miners or mine operators. In addition, some apparatus collected for this study had not been returned to the manufacturer in a recall effort for correction of a manufacturing defect. In both cases, the apparatus would have presented problems in emergency use. Recommendations include improved training in inspection procedures and better enforcement of recall notices.

Jan 1, 1994