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By L. E. Dalverny

This Bureau of Mines report describes the deployment, 5-month operation, and lessons gained from a continuous gas monitoring system using sampling-tube bundles at an underground mine fire in West Virginia. Research information gained indicates the utility of relating certain gas concentration ratios to events during fire development, mine reventilation, and mine recovery. In addition to monitoring the quality of remote fly ash seals, the system provided timely warning of dangerous gas concentrations which developed during surface and underground recovery activities. An evaluation of system components is supplemented by recommendations for improvements.

Jan 1, 1975

By A. R. Rule

This report describes preliminary studies by the Bureau of Mines to develop a procedure for extracting the fluorine from low-grade fluorspar ores in which the CaF2 particles are finely locked in the calcite matrix. A combination of flotation beneficiation and pyrohydrolysis is applied to recover and to liberate the fluorine. Flotation of a finely locked high-calcite fluorspar ore containing only 11.7 pct CaF2 recovered over 92 pct of the fluorspar at a grade of 51 to 52 pct CaF2. Pyrohydrolysis of the flotation concentrate liberated nearly 90 pct of the fluorine as aqueous HF. By this procedure over 80 pct of the fluorine contained in the original ore was extracted.

Jan 1, 1974

By Harry W. Campbell

In 1986, at the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines studied parts of the 19,747-acre Lower John Day (OR-005-006) and 7,538-acre Thirtymile (OR-005-001) Wilderness Study Areas in order to evaluate their identified mineral resources. The study areas are located in Gilliam and Sherman Counties, OR, about 13 mi west of Condon. The area is underlain by the Miocene-age Columbia River Basalt Group. The Thirtymile study area is inferred to have 790,000 yd3 of subeconomic gold resources averaging 93.8 mg/yd3 gold ($1.21 yd3 at a gold price of $400 per oz) in two river bars. The Lower John Day study area has five river bars with gold occurrences totaling 1.0 million yd3 and averaging 13.5 mg/yd3 ($0.17 yd3) gold. A preliminary mining feasibility estimate suggests gold could be profitably mined in the study areas from placer deposits containing at least $3.83 yd3 in gold content. Stone, sand, and gravel occur in the study areas, but more accessible deposits are closer to regional markets. No mines or prospects are in or near the study areas; however, one lode mining claim, now abandoned, was located in the Thirtymile study area. Oil and gas leases cover both study areas.

Jan 1, 1987

By T. T. Read, T. L. Joseph, F. H. Royster

In a preliminary study of the beneficiation of iron ores conducted by the Bureau of Mines, one of the authors (T. T. Read) found it necessary to ascertain, if possible, how much effect a decrease in the silica content of an iron ore has upon the cost of making pig iron from the ore. In the beneficiation of iron ores the most important impurity to be removed is usually silica, and the amount that can be expended on a beneficiation process to reduce the silica content of the ore is obviously determined by the amount of increase in the value of the ore after beneficiation. The price that can actually be obtained for a beneficiated ore is, of course, a matter of negotiation between the seller and the buyer, but since the relative value of different grades of iron ore must be chiefly based upon the cost of making pig iron from them, an approximation as to the effect which decrease in the silica content of ore has upon the cost of snaking pig iron is an important guide in estimating what probable average gain will result from subjecting an ore to a beneficiation process. A search of the literature failed to reveal any detailed statement on this important topic, but fortunately the data are at hand to permit making an approximate calculation of the probable effect. For the purpose of the calculation assume three iron ores with the following composition (natural):

Jan 1, 1924

By R. V. Ramani, K. Bode

"IntroductionThe theory of particle dispersion and deposition in turbulent flow is important to many fields of science and engineering. Dispersion has been studied in some detail since the early fifties (Taylor, 1954; Fischer, 1967; Osipov and Grekov, 1968; Skobunov, 1970 and 1973; Klebanov and Martynyuk, 1974). A broad research effort has also been underway in studying the mechanics of dry particle deposition. Friedlander and Johnstone (1957) proposed a theory, according to which particle deposition from vertical pipe flow could be described by an eddy diffusion transport followed by a final flight to the surface. There have been numerous revisions and additions to this original theory (Owen, 1960; Liu and Agarwal, 1974; Liu and llori, 1974; El-Shobokshy and Ismael, 1980) The mining process essentially consists of breaking in situ materials and transporting them out of the mine. An inherent characteristic of this process is the generation of fine particles. Fine airborne particulates are associated with a number of threats to the health of the miners; fine coal dust can also result in mine-wide catastrophic incidents such as dust explosions. For these and other reasons, it is important to understand the behaviour of airborne dust particulates, particularly their generation, entrainment, transport, dispersion, and deposition in the mine environment for their control.Mine related studies on dispersion and deposition have been few. Yet, several studies of gas and dust dispersion, diesel exhaust contamination, and methane ingress into mine workings have recognized the need for developing reliable parameter values for fundamental understanding of the phenomena (Da""Yes and Slack, 1954; Hodkinson, 1957; Hodkinson and leach, 1958; Mass and Wildschut, 1966; Airey, 1969; Courtney et al., 1986; Stefanko, Ramani, and Thakur, 1974; Stefanko, Ramani and Kenzy, 1977; Bhaskar, 1987, Bhaskar and Ramani 1990; Qin and Ramani, 1989; Shankar and Ramani, 1990)."

Dec 1, 1995

By Russell R. Trengove

Core samples from an ore horizon 2,000 feet below the surface were successfully obtained by rotary drilling at the property of the Eureka Corp., Eureka, Nev. The ore was soft and friable; cores were not obtained previously with diamond drills. Whipstocking was used to get samples in a zone 200 feet from a vertical hole. A technique in shipstocking, by which the direction and deviation of the holes were controlled by means of nonfriction-type survey instruments, was successfully employed.

Jan 1, 1956

By Alan D. Hartman

The U.S. Bureau of Mines, under a Memorandum of Agreement with the American Society of Mechanical Engineers (ASME), established design criteria for a facility to melt residues from municipal waste combustion. This facility, which is available to potential users on a cost-sharing basis, is also applicable to a variety of inorganic waste materials from smelting or melting operations. The design consists of a mechanical feed handling system, electric arc melting furnace, fume-offgas handling system, and thermal oxidizer for final offgas treatment. Screw conveyors and a bucket elevator deliver up to 2,000 lb/h of minus I-in material to a three-phase electric arc melting furnace. This unique 800-kV?A furnace has a water-cooled shell and roof to minimize interaction of the melt with the refractory lining. The volume of the hearth below the slag taphole is approximately 1.2 st of steel. The furnace is sealed, allowing atmosphere control within the furnace and fume duct by nitrogen or inert gas injection. A jet-pulsed baghouse removes particulate from the offgas and serves as an acid gas scrubber. The clean offgas is heated to 1,800° F for 1 s in a propane-fired thermal oxidizer before being vented to the atmosphere.

Jan 1, 2010

By J. S. Miller

The Bureau of Mines developed methods for fragmenting oil shale formations with chemical explosives to prepare oil shale for in situ retorting and to evaluate the extent of fragmentation by various methods. A combination of three methods of explosive fracturing was used: (1) The displacement and detonation of a liquid chemical explosive in a natural fracture system; (2) the use of 60-pct dynamite to relieve stress conditions of the rock around the wellbore; and (3) the use of pelletized TNT in a series of wellbore shots to fragment the oil shale. An attempt was made to seal or grout around the fragmented oil shale by drilling 67 holes and displacing approximately 200 bbl of neat cement in the fracture system to aid in evaluating the fragmented zone, Seven methods were used to evaluate the fragmented zone. The primary evaluation method was the recording of seismic waves to delineate the fragmented zone with results based on arrival time, amplitude, and record quality. The data from the seismic measurements indicated the extensively fragmented zone was approximately 95 ft in diameter and 70 ft thick. Results of the remaining methods of evaluating fractures--including air-flow tests, coring of the expected fragmented zone, elevation measurements to indicate overburden crowning, and surveys with high-speed camera, impression packer, and down-hole camera--agreed with and supported the data from seismic measurements. Further field application of explosive fracturing and evaluation methods is needed to determine when a zone of oil shale is effectively fragmented for efficient in situ retorting.

Jan 1, 1973

By Mary A. Barrett

The Bureau of Mines conducted a laboratory-scale investigation of grouting mixtures containing iron or aluminum to determine the existence of health or explosion hazards, due respectively to oxygen depletion or hydrogen emission. Mixtures containing iron created an oxygen deficiency in less than 24 hours and released small amounts of hydrogen; a health hazard could occur but only under extremely unfavorable conditions. Mixtures containing aluminum released little hydrogen and consumed little oxygen; however, if improper on-site mixing yielded high local metallic aluminum concentrations, enough hydrogen might be released to produce an explosive atmosphere in a confined space.

Jan 1, 1969

By C. P. Lazzara, Y. Miron, A. C. Smith

This report presents a U.S. Bureau of Mines study to identify the causes of self-heating events beneath the floor of a deep underground coal mine. Mine samples from both heated and unheated areas were examined by various techniques, including visual, microscopic, thermal, chemical, and instrumental tests. The combined results led to the conclusion that pyrite (FeS2) oxidation was the prime cause of the beatings. However, adiabatic oven tests of selected samples did not indicate the effect of the pyrite on the self-heating process, probably because of the experimental conditions. A fast, simple procedure to assess the concentration of pyrite in the mine samples was developed, utilizing the reactivity of the sample with an aqueous solution of hydrogen peroxide (H2O2)

Jan 1, 1992

By M. J. Ferrante

Relative enthalpies of V20S from 298.15 to 1,101.0 K were measured at the Bureau of Mines to provide data needed for the advancement of min-eral technology. Enthalpies were measured with a copper-block calorimeter. A sharp melting point was found at 951 K, with [~~ = 15.690 kcal/ mol ] for the standard enthalpy of melting. Tabulated values are given at selected temperature increments between 298.15 and 1,500 K for the standard relative enthalpy [(HO -H~98),] heat capacity (CpO), entropy (SO), and Gibbs energy function [-(Go -H298)/T]. Standard relative enthal-pies are also given in equation form and combined with data from the literature to derive values of standard enthalpies of formation and Gibbs energies of formation.

Jan 1, 1986

By Leslie H. Sharp, Martin J. Gavin

Those of the oil-shale operators in this country who are sincerely attempting to make a real industry out of oil-shale developments, are anxious to obtain fundamental data on the retorting of oil-shale; particularly as regards the effect of certain variable factors in the process of retorting on the quantity and quality of products yielded from oil shales when they are subjected to destructive distillation. From careful examination of a con siderable number of suggested processes for treating oil shales and the con flicting ideas on which they are designed, it seems probable that accurate information of a fundamental nature is highly essential to the successful establishment of an oil-shale industry in this country. . Accordingly, the United States Bureau of Mines, in cooperation with the State of Colorado, is undertaking to furnish some definite and impartial information of this type through investigations now under way at the University of Colorado, Boulder, Colo. A retort for the distillation of oil from oil shale has been designed and installed, together with the necessary auxiliary equipment for controlling and determining variable factors of distillation, and for recovering and de termining the quantity and quality of the products yielded from the shales. The retort is of such a nature that conditions of retorting can be accurately . and completely controlled, and varied at will. It is not designed as a com mercial retort, but only for research purposes. A testing laboratory with equipment necessary for the examination of the shales, physically and chemic ally, and the products yielded by them, has also been fitted up . The material used in the investigations is oil shale obtained from the DeBeque, Colorado, shale field. It yields on distillation in the Bureau of Mines testing apparatus, about 42 gallons of oil to the ton, and is there fore a fairly representative sample of the shales that probably will be first worked in Colorado. The shale used will be as uniform as possible in character and oil yield and will all be obtained from the same seam at the same point, in order to avoid the introduction of unnecessary variable factors in the tests and to render results strictly comparable •

Jul 1, 1920

The principal activities of the Bureau of Mines Pittsburgh Mining and Safety Research Center during fiscal year 1971 (July 1, 1970, to June 30, 1971) are reviewed in part 1 of this paper. Part 2 summarizes publications during fiscal year 1971.

Jan 1, 1974

By Joanne L. Johnston

Researchers at the U.S. Bureau of Mines have developed a new technique for bonding strain gauges to rock bolts. These instrumented bolts are used to determine load at intervals along the length of the bolt so that reliable, consistent measurements for the design of support systems can be obtained. In this Information Circular, this technique is described in detail and should result in improved miner safety in underground mines.

Jan 1, 1993

By W. G. Bradley

THIS PAPER describing the quarrying, mining, and crushing of gypsum at the Blue Diamond mine, 11 miles from Arden, Nev., on the Union Pacific Railway, is one of a series on gypsum mining being prepared for and published by the Bureau of Mines. These papers are designed to disseminate technical information regarding the methods used. The cost tabulations represent operating expenditures only and not total costs. It is recognized that publication of total production costs might in some instances cause embarrassment to individual producers as well as to the industry as a whole. On the other hand, operating costs are essential to the technical discussion and study of the methods employed. The attention of the reader is specifically called to this differentiation in order that no misunderstanding of the scope of the cost tabulations shall ensue.

Jan 1, 1932

By Fred C. Turin, Lisa J. Steiner, Kim M. Cornelius

Like many experienced workers, remote control continuous miner operators perform their everyday jobs making choices and decisions that they may not consciously think about. While performing tasks, they are continuously processing feedback and cues which guide them for the next move. Initial training teaches the operators the tasks necessary to operate the equipment and perform the job. However, with experience they are better able to deal with hazardous conditions and non routine situations. To better understand what potential cues and feedback help to guide the operators, a questionnaire was developed to learn what factors affect decisions. Operator responses address issues related to specific tasks, equipment operation, visibility, lighting, and communication issues. The information collected is useful to understand what cues experienced operators use to make task performance decisions. Results will be used to develop interventions and training for safe and effective operator performance.

By Thomas M. Kohler, Gerald L. Finfinger, Gregory M. Molinda

The Bureau of Mines has completed an investigation of the effectiveness of methane drainage in the Lower Sunnyside Coalbed at Kaiser Steel Corp.'s Sunnyside No. 1 Mine in Utah. Most of the previous at- tempts to drain methane gas using long horizontal holes were conducted in the Eastern Coal Province. From the high degree of success realized in these efforts and the large body of knowledge gained from associated research, it seemed natural to extend the technology to western coalfields. Previous work had indicated that properties affecting gas drainage were variable in the Sunnyside Coalbed. In an attempt to characterize these properties, four degasification holes were drilled from the out- side entries of an advancing section. The holes were drilled to lengths of 780, 1,680, 1,315, and 1,047 ft and produced initial flow rates of 50,000, 180,000, 340,000, and 240,000 f t3/d, respectively. A total of over 300 million f t3 of commercial-quality gas has been removed from the Sunnyside Coalbed. The four holes have reduced face emissions by 78 pct.

Jan 1, 1986

By David M. Hopstock

To help assure an adequate supply of minerals to meet the Nation's economic and strategic needs, the Bureau of Mines is conducting bench-and pilot-scale research using wet high-intensity magnetic (WHIM) separation to recover iron from oxidized taconites of the. Lake Superior region. The advantages and disadvantages of WHIM separation in relation to other separation methods, the most recent innovations in WHIM flowsheet design, and the role of mathematical models in process optimization are discussed.

Jan 1, 1979

By T. J. McDonald

The methods used and the results obtained in the application of high-expansion foam on a recent fire in an operating mine in western Pennsylvania were reviewed. This is the first instance where foam has been applied extensively to a fire under actual mining conditions although considerable research has been conducted and experimental fires have been controlled. The Bureau of Mines began investigating the foam-plug technique in 1957 in its experimental coal mine, following reports of successful trials in Eng-land, where the basic methods, using the normal ventilating current, were developed. Early in the research it was apparent that the normal ventilating current in mines in the United States would not provide adequate air pressure to drive a foam plug the distance that might be required. Subsequently, the Bureau of Mines developed a portable high-expansion foam generating unit consisting of a fan having relatively high pressure potential, net, sprays, and metering equipment. To date, foam generators have been constructed by the Bureau, by at least one operating coal company, and by one manufacturer of safety equipment. A number of units from the latter supplier have been adopted by coal-mining companies as an integral part in their firefighting installations.

Jan 1, 1961

By H. E. Peterson

A study was undertaken by the Bureau of Mines to develop a simple, reliable test for field detection of selenium in rocks and soils. Two methods are described for qualitative detection of selenium, dependent upon its form of occurrence and the presence of interfering constituents in the sample. Both methods involve fusion of the sample in a test tube to form elemental selenium that will volatilize and condense as a red deposit on the cooler upper portion of the test tube. The methods are sensitive to 10 parts per million, (p.p.m.) equivalent to 0.001 percent, and can be made semiquantitative by using suitable standard samples. INTRODUCTION Although selenium is widely distributed in the United States, the known deposits are either so small or so low grade that they cannot be processed economically for selenium alone-4/ At present, commercial production is a byproduct of the smelting and refining of base-metal ores, particularly copper.5/ About 0.75 pound of selenium is recovered per ton of electrolytic copper, and small amounts are recovered by special treatment of assorted smelter dusts and fume products. Since selenium is a strategic metal in short supply, new sources are being sought by both Government and private interests.

Jan 1, 1957