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By J. R. Hoskins

A recent survey of 23 vein-type metal mining operations in several western states discloses that some of the more serious deficiencies in ventilation technology are associated with inordinately high levels of mine resistance. This problem has progressively increased over many years of operation (without adequate remedial action) as mines have become extended in depth. Where two shafts form the downcast and upcast airways of a relatively deep mine, the whole of the mine air volume must pass through each shaft in turn. Since at least one of these shafts contains hoisting equipment, structural members are necessary to support the rigid guides and shaft walls. These offer high aerodynamic resistance. In some deep mines, a single shaft of this nature may represent upwards of one-half of the total mine resistance. The second shaft, depending upon its design, may represent an additional one-third of the mine resistance. Therefore, the various working levels throughout the mine contribute only the small remaining amount of the total mine resistance.

Jan 1, 1972

By F. F. Aplan

"The material known as coal has a highly variable composition. As a consequence, coals show a great variation in their physical and chemical properties as a function of coal rank. The situation is further complicated because the preparation engineer must deal with raw coal, as mined. This is an assemblage of coal, upwards of 30% mineral matter and, typically, several percent pyrite. The kind and amount of the mineral constituents is also highly variable from source to source. A knowledge of coal rank and source location, and the kind and amount of associated impurities, is the first step in evaluating the response of a raw coal to preparation procedures. The raw coal must first be characterized before information from one source can be extrapolated to that of another.INTRODUCTIONCoal is a black or brownish-black combustible solid, derived from a heterogeneous mixture of plant remains and associated mineral matter that have undergone chemical and physical metamorphic changes by biological and geological processes without free access to air. It is composed principally of carbon, hydrogen and oxygen with lesser amounts of nitrogen and sulfur. 'Its exact chemical and physical nature has remained poorly defined, because the term 'coal' refers to a broad range of coalified solids ranging in rank from anthracite to a variety of bituminous coals of differing volatile matter content, sub-bituminous coals, and ending with lignite and brown coals. The variation in chemical and physical properties through these ranks is massive. In summary, Luckie's (1988) assertion is apropos: ""There is no such thing as coal; there are coals"". The coal preparation engineer, and, most especially, those scientists and engineers from other disciplines wishing to work with coal, must constantly keep this admonition in mind because what is true for one coal seam is often not directly applicable to another."

Jan 1, 1989

By M. C. Malamphy

A general description of the activities and results of bauxite investigation by the Bureau of Mines at its bauxite project in Saline and Pulaski Counties, Ark., has been given in Report of Investigations 4251. The factual data obtained during the project are reported in a series of Reports of Investigations beginning with No. 4251, of which this is the third. The data are accompanied by maps showing the location of holes drilled and deposits developed. Each area upon which work was done is reported by half townships. Each bauxite deposit investigated was assigned a name and a number for ready reference and identification, and its location and name are shown on the appropriate half-township-map. The description of each half township is followed by a description of each deposit developed in that half township.

Jan 1, 1948

Between 1985-1986, the Bureau of Mines reviewed the mining history and minerals information for areas in and near the San Isabel National Forest to appraise the mineral resources present and determine the types of deposits, and their location in the Forest, that could be mined economically if sufficient demand and metal prices existed. The two major metallic deposit-types that are of national mineral resource significance within the Forest are stockwork- molybdenum (with tungsten and tin) and carbonate-replacement zinc-lead-silver deposits. Historically, small gold placers, gold-quartz veins, silver-quartz veins, skarn iron and copper deposits, volcanogenic copper-zinc-precious metal deposits, and base- and precious-metal veins have been mined. Barite, carbonate rocks, gypsum, other non-metallic deposits, and pegmatites, have also been mined. Sand and gravel, present in large volumes, occurs along and has been mined outside the Forest along the upper Arkansas River valley. Turquoise and gemstones are present in small amounts and are of interest to collectors and jewelers. Geologically, sediment-hosted uranium and copper are present in small occurrences but no resources have been identified. Geothermal resources are related to the Rio Grande rift which parallels the central part of the Forest. Four hot spring areas are present - two of these are within the Forest. Because of the low power requirements of the region, and the presence of other generating facilities, these geothermal resources have had only limited local use. Evaluation of mine models that may be found in the region show that base-metal deposits require a high precious-metal component to be economic. Although molybdenum can be produced at economically competitive prices, there is little demand for the product. Capital costs to start new molybdenum mines would be very high and it is not likely that new mines will be put into production in the near future.

Jan 1, 1989

By William J. Campbell

This analytical method development and evaluation was undertaken by the Bureau of Mines to provide accurate determinations of eight minor elements in low-alloy steels prepared from ferrous scrap. Fluorescent X-ray spectrography was the principal method investigated. Confirming analyses were made by conventional instrumental and chemical methods. All X-ray data were processed by a timesharing computer. No corrections were found necessary for inter-element effects or overlapping spectral lines. Concentrations were calculated from the least-square fit of a linear calibration equation derived from measurements on three sets of standard steels. These studies show that X-ray spectrographic analysis of lathe-finished surfaces provides accurate determinations of aluminum, copper, chromium, manganese, nickel, phosphorus, silicon, and tin.

Jan 1, 1973

By D. H. Desy

The Bureau of Mines studied the properties of copper that had been oxide dispersion-strengthened with 2 vol pct of either yttria or alumina. Compounds of copper and aluminum or yttrium, coprecipitated from aqueous solution, were converted to oxides; the copper was reduced, compacted, sintered, and extruded. For the resulting copper-dispersoid composites, room temperature tensile properties after annealing in hydrogen, elevated temperature tensile and stress-rupture properties, and electrical conductivity were determined. Compared with oxygen-free copper, copper-2 vol pct alumina or yttria had improved strength after annealing between 400° and 1,000° C, and improved elevated temperature strength, with little loss in electrical conductivity.

Jan 1, 1969

By Ivan F. Avery

DOMEST1C production of carbon black in 1963, remained at about the same level as in 1962. Carbon black produced by the furnace process increased 2 percent to 1,880 million pounds in 1963 and accounted for 91 percent of the total output. Channel black production continued to decline and was 14 percent less than a year ago. Shipments during 1963 totaled 2,098 million pounds, a 1 percent increase for the year. An increase of 88 million pounds in domestic sales was partially offset by a decrease of 72 million pounds in carbon black exports. Total value of carbon black production in 1963 was $148 million. The average value per pound was 7.18 cents or 0.12 cent per pound more than in 1962.

Jan 1, 1964

By P. C. Van Natter

Numerous mine fires have resulted in high death tolls and considerable finan¬cial loss during the history of coal mining. In most instances the death toll and financial loss were greater because of inadequate fire-fighting facilities. The information in this report is presented in the hope it may serves as a guide in the selection, placement, and care of fire-protection systems in similar coal mines. The adequacy of fire protection varies according to size of operation, employment, and production. When fires occur on the surface or underground, measures must be applied quickly to prevent incipient fires from spreading. The record of coal-mine fires shows that, in many instances, facilities for combating fires were very meager or were absent. It would be virtually impossible to establish and maintain all the necessary facili¬ties that may be needed to extinguish widespread mine fires, but it is believed that the coal industry can ill afford less than the minimum required by other industries where the time element and avenues of escape are much more favorable.

Jan 1, 1958

By Alice M. Chieruzzi

This Country Documentation Report presents the development of economic indices for the Philippines for the period from 1970 through 1981. The work was done through the Bureau of Mines, Minerals Availability Program, under Contract number J01225001. This contract calls for the development of twelve index time series describing factor input costs in the mining sector of 95 countries. The twelve index time series describe the costs of: 1) mining wages, 2) construction wages, 3) equipment and repair parts, 4) bits and related steel, 5) eimber and lumber, 6) fuel, 7) powder and balsting agents, 8) tires, 9) construction materials, 10) industrial materials, 11) transportation, and 12) electrical power. These indices combined with weight factors being developed by the personnel of the Minerals Availability Field Office (MAFO) of the Bureau of Mines in Denver, Colorado, will be used to perform instantaneous updates of all costs relating to the mining industry. The indices were developed primarily for use in the Bureau's Minerals Availability Program in assessing the worldwide availability of nonfuel minerals.

Jan 1, 1983

By K. J. Miller

A laboratory electrophoresis column was designed to separate pyrite from fine coal by utilizing an observed difference in the electrophoretic mobilities of the two materials in water. The apparatus worked well when tested with synthetic mixtures of coal and pyrite, but some modifications in design and procedure were necessary to provide a sharper separation. After these changes were made, the column was tested with a high-pyritic-sulfur raw coal sample. The column successfully fractionated the sample, removing not only the pyritic refuse, but a siliceous refuse as well. The invest ion demonstrated on a laboratory scale that pyrite and other impurities can be separated from fine coal by electrophoresis.

Jan 1, 1970

By R. W. Stahl

Increasing use of continuous miners, especially the boring type, has focused attention on the inadequacy of face ventilation in coal mines. The bulk of the machine, the rapid advance of working faces, and the increased liberation of methane from the larger expanse of freshly exposed coal surfaces have created ventilation problems that were unknown with conventional mining equipment. Ignition of gas, especially that caused by machine bits striking hard rock or pyritic inclusions, have increased at an alarming rate. As the mines penetrate beds under thicker cover at an ever-increasing rate of face advance, this problem will probably increase unless face ventilation is improved. A previous survey, described in Bureau of Mines Report of Investigations 5414, Auxiliary Ventilation of Continuous Miner Places, disclosed that auxiliary fans with tubing generally improved circulation of air and removal of gas at the face. The study here reported attempts to examine, face ventilation at various mines and to note any plan or innovation of. air coursing that industry might adopt to reduce the danger of gas ignition. ACKNOWLEDGMENT The mines visited were very cooperative in the study-and-generously supplied any data requested.

Jan 1, 1960

By Arnold B. Hubbard

Automatic control instruments were utilized by the Bureau of Mines for routine assays of large numbers of oil shale samples and other bituminous materials. The standard Fischer assay method was automated by automatically controlling the heating cycles of a battery of 12 electric heaters with electronic controllers and programmers. The condensers were cooled with a modified automatically controlled refrigeration bath. The complete assembly consisted of 12 retort units, necessary control instruments, and the refrigeration bath. This equipment was capable of producing more consistent results than those previously obtained with the gas-heated retorts and of increasing the output of assays substantially with no increase in operating personnel.

Jan 1, 1965

By J. T. Dunham

The Bureau of Mines studied by dilatometry the effect of titanium on the thermal expansivity of hot-rolled zinc and Zn-l percent Cu alloy. The titanium content of the alloys was varied up to 0.3 percent. Expansion coefficients were determined from measurements made both parallel and perpendicular to the plane of the rolled sheet. Titanium reduced expansion parallel to the plane of the sheet, especially in the rolling direction, but increased expansion perpendicular to the sheet. Basal-plane pole figures showed that the degree of preferred orientation increased with the titanium content in the alloy, and that anisotropic expansion can be correlated to sheet texture.

Jan 1, 1965

By Ruth F. Brinkley

Principle activities of the Bureau of Mines Explosives Research Laboratory from July 1, 1960 to June 30, 1961 are reviewed briefly in Part 1. Part 1 also includes data obtained in connect ion with several minor investigations which are not sufficient to warrant separate publications. Part 2 gives brief abstracts of publications that appeared during fiscal year 1961; in general, the research reported in these publications antedates this period.

Jan 1, 1963

By Raja V. Ramani, Wilson Miola

"The potential health effects of quartz-bearing airborne dust in mine and mill atmospheres point to the need for the quantification of quartz content in the source material for determining the source-sink relationships and for choosing applicable control measures. While a standard method exists from a regulatory point of view for the sampling of coal mine atmospheres for determining (i) respirable dust concentrations and (ii) the amount of quartz in the samples, there is no generally accepted standard method for quartz analysis in bulk samples of coal and host rocks. Generally, the bulk sample is reduced to a powder for producing quartz analysis samples. Extensive controls arc necessary to ensure representativeness of the analysis samples when these are very minute fractions of the bulk samples. Since the amount of analysis sample is not limited, alternative methods for quartz analysis may also be tried. It is, however, necessary to adopt a procedure which will satisfy several statistical requirements to guarantee representativeness of the quartz analysis samples.In this paper, the important factors in the preparation of quartz analysis samples from the host rocks and bulk samples are discussed. The method developed to prepare the analysis samples is outlined. The results of application of the procedures are presented. The procedure developed for quartz analysis sample preparation is based on sound statistical foundations. The procedure has been validated for reproducibility and homogeneity.The current methods used for quartz analysis in powders are the P-7 infrared spectrometry and quantitative X-Ray Diffraction (XRD). Both have similar restrictions concerning the sample characteristics and operational problems, which arc intrinsic to radiation beams, device geometry, mechanics and controls of the radiation behavior. Although improvements can be made in the spectrometers and diffractometers, some of the most important steps are the procedures for analysis sample preparation from bulk samples and for calibration of the instruments. The sample preparation process is often referred to as one of grinding and sizing the bulk sample to generate the powder for the scanning devices. The particle sizes are referred to and their influence emphasized but the representativeness of the sample is assumed. Assuring sample representativeness during the sample preparation procedures is critical.For the sampling of airborne respirable dust in coal mines, the collection devices, the collection procedures and the analysis procedures are defined. This is not true for bulk samples where weights must be reduced thousands of times to generate the analysis samples for the scanning devices. The specifications to be developed may include bulk sample amount, sample reduction procedures, sample particle size distribution and sample amounts. However, the common problem of insufficient sample amount which is often encountered with mine airborne dust samples need not exist for bulk samples. Further, the same bulk sample can yield analysis samples for several experiments. The latter, of course, requires sample homogeneity.Three concepts are important in the selection of any procedure for sample preparation and analysis. These arc accuracy, reproducibility and representativeness. The adopted procedure has to guarantee a homogeneous sample representative of the population, a defined level of accuracy and reproducibility. Important statistical concepts are embedded in these requirements, particularly with respect to estimation and dispersion errors. Accuracy and reproducibility are totally different though not independent concepts. Estimation is related to accuracy and the true value. Dispersion is related to reproducibility and is measured by the classical statistical standard deviation of the distribution of a series of measurements or analysis performed over the same lot or analysis sample. The dispersion variance (or dispersion error) does not tell a"

Mar 1, 1992

By Patrick D. Plumb

The Bureau of Mines (BOM) has begun a project to increase the understanding of the relationships between ecosystem health and its functions, and minerals development. The BOM, Juneau Branch, Alaska Field Operations Center, is providing support for ecosystem based land-management decision-making and the development of ecosystem based regulations by documenting the effects of mining on ecosystems and demonstrating the tools used to assess and analyze those effects. This is done by reviewing the data available on ecosystems and the environment at a mining site, the Greens Creek Mine near Juneau, Alaska, and applying available Geographic Information System modeling tools to assess the impacts of the mine on components of the pristine ecosystem. Habitat Capability Models for wildlife indicator species are used in this examination. Wildlife indicator species are used as indicators of ecosystem health by the U.S. Forest Service and the Alaska Department of Fish and Game, who developed these models for southeast Alaska. Analysis techniques from the U.S. Fish and Wildlife Service's Habitat Evaluation Procedures (HEP) are also used in this report. By applying available models and analytical techniques to the Greens Creek area, the benefits gained through mitigation of potential impacts become apparent. These or similar techniques are useful for cost/benefit analysis of mitigation alternatives. Also apparent from this analysis is that the degree to which potential impacts are observable will depend upon the ecosystem scale considered. This demonstrates the importance of defining the ecosystem and scale before performing impact and cost/benefit analysis. The watershed scale is found to be useful for assessing impacts to ecosystem components at the Greens Creek Mine. Much progress remains to be made in the modeling and prediction of impacts to ecosystems from mining activity.

Jan 1, 1994

By K. O. Bennington

The thermodynamic properties of hedenbergite, of composition [(Ca0,9516) (Mg0,0583Fe2+0.7134 Fe3+0.0934 Mn0,1366) (Si206)], were experimentally determined at the Bureau of Mines. The standard enthalpy of formation determined by hydrofluoric acid solution calorimetry is AHf298 = -680.96±0.855 kcal/mol. The standard enthalpy of formation from the oxides is AR-96 = -24.55±0.485 kcal/mol. Low-temperature heat capacities were determined by adiabatic calorimetry from 12.3 to 300.1 K. The derived standard entropy is S-98 - 41.218±0.148 cal/mol-K. High-temperature heat capacities were measured with a differential scanning calorim¬eter from 397 to 1,147 K. These experimentally determined data were combined with data from the literature to calculate the Gibbs energies of formation and equilibrium constants of formation over the temperature range of measurements. Standard enthalpies of formation are given as a function of temperature. The standard Gibbs energy of formation at 298.15 K is AGf298 = -641.90±0.86 kcal/mol.

Jan 1, 1984

By J. Ribovich

The current Bureau of Mines active list of permissible explosives includes 71 brands. Eleven are gelatinous, 56 are the granular type, and four are water-gel explosives, an entirely new type of ammonium nitrate-based explosive for use in coal mines. The list of permissible blasting devices comprises five Cardox models.

Jan 1, 1973

By G. R. Hopkins, A. B. Coons

A survey of the petroleum pipe lines by the Bureau of Mines as of May 1, 1923, shows that on that date there was a total of slightly more than 90,000 miles of pipe lines in the United States, having a capacity of approximately 15,750,000 barrels, which is equivalent to one-fourth of the nation's average production for one month. These lines varied in diameter from 2 to 16 inches, the weighted average being 6 inches. The total pipe-line milenge was about equally divided between trunk lines and gathering lines, though the capacity of the former was about four times that of the latter. This was due, of course, to the difference in average diameter, that for the former being 7.4 inches as compared with 3.7 inches for the latter. The common size for trunk lines was 8 inches, and for gathering lines 2 inches. Oklahora, with 19,180 miles of pipe lines, is the leading State in total mileage, with Texas second and Pennsylvania third. From point of trunk lines alone Texas is considerably ahead of any of the other States, a position which it owes to its size and to the growth in the rovement to its Gulf ports. Cali- fornia, though the leading State from point of production, ranks only seventh in pipe-line mileage. This is due to the fortunate location of the Los Angeles Basin fields, some of which are within sight of the refineries to which their oil is delivered or of the port of San Pedro through which their oil is shipped. The last survey of this nature, made in the spring of 1924 by the U. S. Geological Survey, recorded a total mileage of nearly 83,000 with a capacity of approximately 14,450,000 barrels. This indicates an increase of 9 per cent in both mileage and capacity during the two years.

Jan 1, 1927

By H. O. McDonald

The Bureau of Mines reviewed the chemical vapor deposition (CVD) literature on the nonmetal binary and ternary compounds of the group IVB, VB, and VIB elements, with emphasis directed to the following nonmetals: B, C, N, O, and Si. This review examines each of these binary and selected ternary compounds of the group IVB, VB, and VIB elements as coatings and gives some of their preparative methods, uses, and properties. A total of 259 references were found for these compounds of the nine elements. This review was utilized in the Bureau's research to provide abrasion-, erosion-, and corrosion-resistant coatings in order to conserve critical metals and protect various metallic surfaces in metallurgical, mining, and energy conversion systems.

Jan 1, 1983