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By J. C. Edwards

The National Institute for Occupational Safety and Health (NIOSH) implemented a real-time neural network system which can discriminate mine fires from nuisance diesel emissions as part of an atmospheric mine monitoring system in NIOSH?s Safety Research Coal Mine. The real-time response of a neural network to fire sensor outputs was demonstrated for coal and belt combustion in the presence of diesel emissions. The fire sensors consisted of an optical path smoke sensor, a carbon monoxide (CO) sensor, and two types of metal oxide semiconductor (MOS) sensors. The real time neural network was trained with coal, wood, and belt fire experiments with and without diesel emissions background. The trained neural network successfully predicted mine fires with these combustibles in the smoldering stage prior to the onset of flames.

Jan 1, 2005

By M. H. Kersten, G. A. Brady, Jerry W. Ramsey

Anthracite samples were oxidized with nitric acid to prepare products representing intermediate stages of oxidation . Similar oxidizing conditions affected different anthracites to varying degrees as characterized by peptization behavior with 0.1 N NaOH . Techniques used in attempts to separate and characterize the products included esterification , absorption spectrophotometry , sublimation , chromatography , electrophoresis , metal salt formation , and solvent extraction . Mellitic acid , either free or in the form of metallic salts , was identified in the acid- soluble products from 10 tests in which the anthracite was treated with nitric acid for periods varying from 24 to 1,000 hours . pentacarboxylic acid was also found in some products . Other benzene carboxylic acids were not present in amounts detectable by the methods used in this study . The acid- insoluble residue from nitric acid treatment varied significantly in solubility behavior toward different classes of solvents . The most effective ones tried included polar oxygenated solvents and pyridine . Infrared spectra of the extracted material indicated that similar compounds were extracted by the different solvents . Aliphatic amines and aniline peptized the residue and o- toluidine reacted with it . Organic material separated from the residue by peptization with dimethylformamide contained 1 percent ash , consisting of more than 50 percent zirconium .

Jan 1, 1964

By Robert Stefanko

This report, rather than attempting to replace previous annual reports, supplements, and more importantly, coordinates and summarizes the entire effort. Even with such restrictions, the report is voluminous and, therefore, a decision has been made to divide it into two parts. The first volume is basically narrative and includes tabular results and analyses. The second volume is in appendix form giving detailed information. Together, they permit a logical discussion of all aspects of the project (Volume I) without cumbersome distractions but, at the same time, provide all the details to permit others to evaluate and explain the results or develop similar research programs (Volume II). The aim of the original proposal was basically to develop instruments and techniques and then make measurements of suitable power parameters, ground fault currents and ground resistance beds. With such information available, it was possible to develop a meaningful simulator which would permit investigating electrical systems and components on paper without costly trial and error procedures in the third year, a cable splice testing program was added to the project. While there were the usual delays attendant in such original research, these objectives were achieved.

Jan 1, 1973

By J. A. Kosek

Work has been conducted under Bureau of Mines Contract Number HO 357078 to develop instruments for detecting CO, NO and NO2 in a mine atmosphere, using fuel cell technology. The approach has been to optimize the fuel cell sensor configuration for the specific detection of CO, NO and NO2 in the presence of other mine gases utilizing recent advances in catalyst, electrode and solid polymer electrolyte membrane technology. Para-metric testing has been conducted on three electrode sensor cells to define performance and life characteristics as a function of temperature, feed flow and applied sensor voltage. Extended life testing has been performed on sensor cell configurations exhibiting favorable characteristics. Reliable, efficient gas sampling and electronic control circuitry has been fabricated for use with the sensor cells, and integrated into devices to meet the performance and design specifications for portable, battery-powered, hand held direct indicating gas detectors for use underground. Twenty of the production-type, direct indicating CO detectors have been tested and delivered to the Bureau of Mines under the present contract. Three prototype diffusion head CO monitors have also been delivered for evaluation under the pre-sent contract. The gas sampling pump and related parts have been replaced by a diffusion tube assembly in which CO reaches the sensing electrode surface by diffusion alone. In addition, delivery will be made of ten direct-indicating nitric oxide detectors and ten direct-indicating nitrogen dioxide detectors. These instruments are very similar in design to the direct indicating CO detector.

Jan 1, 1979

By Michael Hamilton

Mineral resources have been identified at seven properties in the, Middle Fork Judith study area (fig. 1, and table 1). Commodities consist of silver, gold, copper, lead, zinc, and marble. Eleven properties (fig. 1 and table 2) have potential for discovery of silver, copper, lead, zinc, or sapphire resources. Of principle interest are the mineral deposits within contact zones between the Yogo intrusive complex and the surrounding Paleozoic sedimentary rocks. Contact alteration zones along the southern slopes of Yogo Peak have been prospected in a 2- to 3-mi (3.2-to 4.8 -km) long belt within the study area.

Jan 1, 1982

By H. G. Hammon

Uranium miners have been shown to develop lung cancer in direct proportion to the time of exposure in the mine and the concentration of radioactivity (cumulative working level).1 Radon gas is continually evolved from the uranium ore, but because of its shoe half-life, 3.82 days, it is soon decomposed into particulate daughter products, which along with the dust in the mine, become deposited in the miners' lungs. At present, massive ventilation is the only effective method of reducing the radioactivity concentration in the mines. However, the Bureau of Mines is evaluating the possibility of using coatings on the mine wall that will have sufficiently low permeability to radon that the gas will decompose into the particulate daughter products before it can permeate the coating. Permanently trapped in the coating, the daughter products would be prevented from dispersing in the mine atmosphere. Lawrence Livermore Laboratory was asked to aid in this investigation. The direct determination of radon permeability is more difficult than that of the other noble gases because of the short half-life of the gas and radioactive contamination of the apparatus. We felt that it should be possible to estimate radon permeation coefficients from other noble gas permeation coefficients. It was noted that the log of the diffusion constants for helium, neon, argon, and krypton, as reported by Meares2,3 plotted to a straight line-against the square of-the gas molecularddia meter. The log of the permeation coefficients also plotted to a straight line against the square of the gas molecular diameter. Thus, by determining the permeation coefficients of such gases as argon and krypton through various films and coatings, it appeared likely that radon permeation coefficients could be estimated. In addition we felt it should be possible to find some relationship between polymer structure and he noble gas permeation coefficient that would aid in the selection of coatings materials as radon barriers.

Jan 1, 1975

By John G. Parker

Important quantities of gold, silver, platinum-group metals, selenium, tellurium, and arsenic are recovered in the processing of copper concentrates. The objective of this Bureau of Mines study was to determine the occurrence of these elements in copper ores and to trace their distribution during subsequent processing steps. The study describes the important areas supplying concentrates, precipitates, and unrefined copper to the copper smelting and refining industry in a composite of the years 1971-74. The relative importance of these areas as a source of the respective byproducts is assessed. The lack of certain quantitative and assay data, recycling of dusts and slags, and the addition of scrap to the feed often complicates calculations and estimations of the byproducts in the smelter-refinery throughputs. Such volatile or low-boiling point elements as arsenic, selenium, and tellurium may be lost in gaseous and other emissions in various processing stages, or they may be concentrated in slags and residues for which samples were not available. The effects of antipollution legislation to improve control of sulfurous and other emissions that may affect recovery of certain byproducts was noted. A section on newer technology illustrating hydro-metallurgical techniques that may affect the recovery of minor metals is included.

Jan 1, 1978

By Loren R. Anderson

Traditionally, an evaluation of the safety of slopes has been based on computing a safety factor against failure. In computing the safety factor, the geometry of the slope, the soil parameters and the pore pressures are treated as deterministic quantities even though they are known to be random variables. A pseudo-three-dimensional probabilistic slope stability model has been developed that treats shear strength as a random variable. The model uses the probability of a slope failure as an assessment of slope reliability. The model can accommodate zoned embankments of soil in which the strength is described by the Mohr-Coulomb strength envelope. Autocorrelation functions are used to describe the spatial correlation of the strength parameters, c and tan ø. Model error can also be included in the analysis. The model has been applied to an existing tailings dam and to several hypothetical examples. These examples are presented to illustrate the influence of the choice of the soil strength variability parameters on the probability of failure. The results show that the critical failure surface based on the minimum safety factor is not necessarily the failure surface that will yield the maximum probability of failure. The analysis of the tailings dam shows that variance reduction can be large and that the model error is the dominant source of uncertainty for the embankment analyzed.

Jan 1, 1982

By T. T. Tomimatsu

[This Bureau of Mines paper investigates explores, and analyses the Corporate structure dynamics and Rancid role to evaluate the economic health of the U.S. copper producers. It highlights the Corporate policy options and measures of corporate profitability and suggests that a competitive domestic copper industry will exist in the future. The study highlights the activities of 14 selected major copper-producing companies, including their subsidiaries o affiliates, that were responsible for more than 95 percent of the total U.S. production in each of the years since 1969. The selected firms are hot all primarily in the business of producing copper. Several of the large producers are classified by the financial institutions as integrated oil and gas enterprises.]

Jan 1, 1980

By S. H. Lorain

Shortly after the Strategic Minerals Act of 1939 we passed by Congress, the Bureau of Mines was authorized to begin a program of investigation of domestic sources of strategic minerals. Since World War I, the Philipsburg district had been virtually the only one in the United States that was producing manganese on a commercial scale. Consequently, the district was among the first to he investigated. During the summer of 1939, the Geological Survey mapped the geology and ore deposits of the district. In late July 1939 the writer examined the district for the Bureau of Mines. On the basis of this examination and of the work performed by the Geological Survey, the Bureau of Mines diamond-drilled at several properties in the district during the summer of 1940. This report reviews the mining history and geology of the district, and presents the factual data obtained by diamond drilling.

Jan 1, 1950

By C. W. Owings

A few of the more progressive mining companies have taken precautions to safeguard employees or man-trips. Specially constructed men-cars -have been provided with special devices or mechanisms to stop the cars on slopes, if the hoisting cable should break. Cars have been equipped with safety chains to connect and hold them together if a coupling should break. Steel frames covered with heavy wire netting have been placed over cars to reduce injuries to the riders from roof fails on slopes. A safety cable passing from the front car to a point above the cable socket on the slope hoisting cable is used frequently as a precaution in case the socket loosens o the main cable breaks at the socket. Such devices are commendable, but the percentage of man-cars and man-trips protected is relatively small - entirely too small. Man-trips that travel level haulage roads are rarely protected safety devices, and haulage roads are seldom inspected by mine officials to determine the condition of roof and ribs.

Jan 1, 1935

By R. V. Thurston, Edmund S. Leaver

"During the development of the sulphur dioxide leaching process for the treatment of ""mixed"" copper ores at the Southwest experiment station of the Bureau of Mines*** the pulp from treatment of roasted cupriferous pyrite with sulphur dioxide gases and water showed an unexpected amount of sulphuric acid. After following out several false premises it was found that this was due to iron in the solution, and also that this iron tended to oxidize to the ferric state if the concentration of sulphur dioxide in the roaster gases used did not rise above a certain figure. While the percentage of iron present was email it was enough to cause an entirely different set of conditions from those of the original sulphur dioxide leaching process and to promise a much wider application of the general idea. Sulphurous acid dissolves only certain copper minerals, sulphuric acid solutions certain additional minerals and ferric sulphate solutions certain further additional copper minerals, so this observation was of importance in connection with possibilities in the hydrometallurgy of the so-called ""mixed"" or partly oxidized copper ores.The work has been carried along by a number of experimenters. L. R. Eckman, junior chemist of the Southwest station, contributed largely to the early developments. L. Roberts, W. D. Bonner and C. G. Maier each in turn physical chemists at the Pacific Experiment station, (Berkeley, Calif.) have studied the reactions involved. A complete report of all the work on this process will be prepared later under the direction of O. C. Rolston. The purpose of the present paper is to place a summary of the more practical phases of this seemingly important piece of work before those interested."

Dec 1, 1923

The investigation summarized in this report addressed two primary issues: the determination and use of correction factors, and the development of guidelines for velocity measurement site selection. Other ancillary issues which were addressed include a comparison of measurement methods and devices, aircourse cross-sectional area measurement, and characteristics of mine airways. An exhaustive literature search and analysis was performed; extensive in-mine experiments were conducted; a quantitative analysis of the data was used to develop correction factor tables and site selection guidelines. The reported results of other researchers who have examined the correction factors and site selection criteria, were analyzed in light of the results of this study. The measurement devices included in the experimental phase were: vane anemometer, vortex shedding anemometer, a prototype thermoanemometer, smoke tube, and, oil of wintergreen. The measurement methods include single-point centerline, timed¬-point traverse, continuous traverse for the anemometers, and various distances and cloud positions for the smoke tube and oil of wintergreen devices.

Jan 1, 1983

By P. T. Brooks

Mineral nodules from the ocean floor represent a vast potential source of manganese, nickel, cobalt, and copper. Process development studies to devise methods for recovering these metals were conducted by the Bureau of Mines using two types of nodules--relatively low-grade calcareous nodules from the Atlantic Ocean and higher grade siliceous nodules from the Pacific Ocean. Ammoniacal carbonate leaching of reduced nodules appeared to have the best potential for processing the calcareous nodules, but the method proved to be impractical for recovering manganese. Extraction of 90 percent or better of the nickel, cobalt, and copper showed the technique to be attractive for recovery of these metals. The siliceous nodules appeared amenable to a process that starts with either a sulfur dioxide leach or a sulfation roast followed by a water leach to dissolve the soluble sulfates.

Jan 1, 1971

By Philip K. Hopke

A systematic study of the mechanism of interaction of 218Po(RaA) armed by the decay of 222Rn with airborne particulate matter has been made. The rate of attachment of RaA to particles in the diameter range of 0.1 µm to 10.0 µm has been measured as a function of particle size, concentration, and composition, radon concentration, time of interaction, relative humidity and temperature. It was found that under the conditions in these experiments the attachment rate was proportional to the square of the particle diameter and varied with temperature and relative humidity. The composition of the particles apparently has no effect on the attachment. The variation in attachment rate was related to a sticking probability coefficient of approximately 0.02 that varies systematically with temperature and humidity. In addition, the rate of deposition of RaA on the wall of the attachment kinetics system was measured and also found to change with temperature and relative humidity.

Jan 1, 1980

By Edward L. Burwell

The Bureau of Mines investigated the use of dilute polymer in brine solutions to increase the efficiency of air in gas flooding model oil reservoirs. Slugs (0.23 pore volume) of 500 ppm polyacrylamide were injected into a model, consisting of a high- and a low-permeability core, that had been previously gas flooded to residual oil. Gas flooding was then resumed. Of the total gas volume injected, the percentage entering the high-permeability zone was greatly reduced after polymer injection but remained unchanged when slugs of water without polymer were used.

Jan 1, 1970

By J. Mitchell Linne

In 1985, at the request of Bureau of Land Management, the U.S. Bureau of Mines studied a 54,480-acre portion of the 93,205-acre Dry Valley Rim Wilderness Study Area (CA-020-615), in order to evaluate its identified resources. The area studied is in Washoe County, NV, and Lassen County, CA, about 35 miles east of Susanville, CA. No metallic resources were identified. The Red Rock and Willow Springs areas contain 85 million tons of altered basalt with zeolite amygdules. This material, averaging more than 50 percent chabazite, constitutes a subeconomic zeolite resource. This zeolite-bearing material would require beneficiation to upgrade it for higher value uses. Natural zeolites have a small market in the United States, which is presently supplied by other higher grade material. There is low probability that these resources will be mined in the foreseeable future. The Capricorn claims, adjacent to the study area, are on alluvial sediments containing more than 30 percent montmorillonoid clays. The material is not usable as pozzolan and was not tested for other uses such as absorbency, oil clarification, or insecticide carrier. The term pozzolan refers to a number of siliceous materials which are combined with portland cement to enhance the physical properties of the resultant concrete. The area is remote from market and contains low value material. It is improbable that this occurrence will be mined in the foreseeable future.

Jan 1, 1987

By B. J. Moore

This publication contains analyses and related source data for 310 natural gas samples from wells and pipelines in 16 States. All of the samples were obtained and analyzed during calendar year 1978 as a part of Bureau of Mines investigations of the occurrences of helium in natural gases of countries with free market economies. This survey has been conducted in the United States by the Bureau of Mines since 1917. In late 1965, the survey was expanded to include foreign gasfields. The analyses published herein were made by mass spectrometer and a special helium analysis appara¬tus, which are described in Bureau of Mines Bulletins 4862/ and 576.3/ The results of the investigation of the occurrences of helium are published annually to make the information available as soon as possible to the gas industry and the public in general. Twenty previous publications have presented the results of 11,573 gas analyses made prior to 197R. The first three, Bulletins 486,4/ 576,5/ and 617,6/ contain analyses and related source data on 5,218 gas samples collected from 1917 through 1960. The other 17

Jan 1, 1979

By B. R. Mohal, F. F. Aplan, S. Chander

"Dust abatement by water sprays involves the subprocesses of 1) collision between dust particles and water droplets, 2) adhesion of particles to droplets, and 3) engulfment of particles by the droplets. A review of the fundamental aspects of these subprocesses shows that collisions between particles and droplets are determined by aerodynamics and the size and surface charge of the particles and of the droplets. However, the adhesion and engulfment subprocesses depend upon the wetting characteristics of the particles. Although wetting agents (also known as surfactants) have been used as dust suppressants in several investigations, conflicting results are available regarding their effectiveness. In this paper, we show that these results can be explained if the effects of coal rank on surfactant adsorption and wetting characteristics are taken into account.The influence of several nonionic surfactants containing polyethoxy adducts on the wetting behavior of coal is presented. The wetting was determined by a modified Walker Test method, and contact angle measurements. The results show that the wettability of coal depends upon coal rank, structure of the hydrocarbon chain of the surfactant, and the number of ethoxy groups in the molecule.IntroductionDue to the inherent nature of the mining process, a large number of particles are generated, a portion of which becomes airborne to create dust. Dust can be aesthetically and environmentally unacceptable and it can also be explosive. Fine particles in the respirable size range ( < 5 urn) are con-sidered to cause lung diseases, namely, silicosis, pneumoconiosis, etc.(1) Several approaches to reduce dust in mine environments are practiced throughout the mining industry. These include decrease in generation of dust through improvements in mine machinery, ventilation (in which lower dust levels are achieved by dilution of contaminated air with clean air), and dust removal methods. Water sprays are most commonly used to remove dust par-ticles. Recently, scrubbers are reported to have been installed on mining machines to remove dust,(2,3) which also make use of water sprays to reduce dust."

Mar 1, 1989

By Mandeep Singh

The smelting of lead ores has been carried out in southeast Missouri for centuries, and modern smelting practices have generated a variety of waste products. Lead blast furnace slag is one such product, which typically contains 10% zinc, 25% iron and 2% lead. This slag has often been stockpiled on the producing smelter site and accumulations have now reached several million tonnes. It is possible that in the near future these slags will be classified by the federal Environmental Protection Agency as hazardous, and therefore there is considerable interest in possible treatment processes to render the slags non-hazardous by removing the offending metallic elements. To ensure that the overall slag processing costs are kept to a minimum, it is imperative that lead and zinc be recovered in a form suitable for sale or further processing. There are two generic routes for processing blast furnace slags and they involve hydro-metallurgical or pyrometallurgical techniques. With hydrometallurgy, the slags would be leached directly and the metal values recovered from purified leach solution(s) by electrowinning. One problem with processes of this type is that the zinc and lead grades of the slags are low and the iron content is high, and thus the economics of metal production are often not favorable. For pyrometallurgical processing (1), it has been shown that the slags can be fumed to produce an oxide dust containing all the lead and zinc, and representing only a fraction of the weight of the initial slag. The oxide dust may then be processed hydrometallurgical to recover zinc and lead.

Jan 1, 1992