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By Charles Will Wright

This paper has been written to aid the owner of a small gold mine or prospect in preparing a report on his property for the purpose of interesting capital. If an owner can afford to do so, he should employ a mining engineer of recognized standing and experience to examine and report on his property, but many owners of small -mines and particularly of prospects cannot make the expenditure required for this. Further, many of them do not know how to prepare a description which will cover those features of a deposit on which a potential investor promises his opinion as to its worth. If such an owner is convinced that he possesses an orebody of sufficient grade and size to warrant the required expenditure for a thorough investigation and wishes to present his property to prospective investors, then the following suggestions concerning the proper way to sample his deposit, estimate the tonnage of developed and probable ore, and prepare a report may be of assistance.

Jan 1, 1933

By J. L. Holman

The Bureau of Mines is conducting research to recover strategic and critical metals such as Ni, Co, and Cr from mixed contaminated super-alloy scrap. One approach being studied involves melt refining of superalloy scrap to produce anodes for electrolytic deposition of Ni-Co alloy. This melt refining of superalloy turnings is described based on melt-oxidation and oxidation-carburization experiments, using roasted superalloy grinding sludge to supply the 0 needed to oxidize Cr and other readily oxidized elements to the slag. Controlled melt-carburization subsequent to oxidation improved the metal phase recovery of Ni and Co to well over 90 pct and decreased electrolytic solubility of Cr, Mo, and W by carbide formation. Electrolytic refining experiments were conducted using a controlled-potential mode (preset cathode potential). Data show effects of Fe and Cr impurities, cation concentration, electrolyte pH, S04-Cl electrolyte ratio, temperature, cathode potential, and cation-selective membrane use on current efficiency, current density, and deposit composition. Disposition of Ni, Co, Cr, MO, W, and Fe is compared for melt-oxidized versus oxidized-plus-carburized anodes. Deposits containing >97 pct Ni + Co (major impurity Fe) have been routinely obtained from scrap anodes. Research is continuing to improve deposit quality in sustained deposition and to recover Cr and other metals from refining slags and anode sludges.

Jan 1, 1986

Provide mine personnel with a convenient means of determining the optimum installation geometry of roof trusses in bedded roof. Background Mine operators frequently ask the following questions concerning roof truss installations: 1. Where should the bearing plates or brackets be placed or where should the inclined holes be started? 2. At what angle should the holes for the inclined chords or angle holts be drilled? 3. What tension should be put into the inclined chords so as to achieve the most effective results for the effort and expense? Truss hardware manufacturers have responded to these questions with answers based on what seems to work best. While designs based on past experience are frequently reliable, there was a need for a rational approach that could accommodate a variety of conditions. The Bureau has developed a procedure that enables mine operators to optimize roof truss installations in bedded roof.

Jan 1, 1989

By D. E. Wolfson

This report presents 900° C BM-AGA carbonization and related data for coals from the principal beds of Nicholas, Randolph, and Webster Counties, W. Va. Thirty-three samples from nine coal beds in three counties were car-bonized at 900° C in the l8-inch-diameter BM-AGA retort, data from which have been correlated with industrial production. Host of the samples were chemically suitable for metallurgical use, and their coking properties were satisfactory. Except for four of the Lower Kit-tanning samples, the ranges of constituents in the coal seams were 1.8 to 9.0 percent ash and 0.4 to 1.1 percent sulfur, values within the range of accept-ability for metallurgical coals. Coke strength indexes were normal for Appalachian coals of similar rank, and the tumbler stability indexes of the coke ranged from 35 to 57.

Jan 1, 1969

By Jos. R. Guiteras

This paper is one of a series describing; mining and milling methods and costs being published by the Bureau of Mines. It deals with the mineral resources of western South Dakota and describes the mining and milling of tantalite and associated amblygonite by the Black Hills Tin Co. and the Fansteel Mining Corporation. ACKNOWLEDMENTS Acknowledgment is made to Earl C. Schultz and Arthur I. Johnson, respectively superintendent and engineer for both the Black Hills Tin Co. and the Fansteel Mining Corporation, who contributed the information on mining and milling operations.

Jan 1, 1939

By Marting J. Gavin

The twentieth century has often been spoken of as the age of petroleum, and from many viewpoints it can be justly considered so. Certainly the petroleum industry is one of enormous importance to this country, industrially, financially, and economically. The United States, however, at present producing over 60 per cent of the world's total output of petroleum, is not producing petroleum at a sufficient rate to provide for its own domestic, consumption. For several years this country has been importing increasing quantities of crude and partly refined oils from Mexico, and has been drawing heavily on domestic stocks of petroleum. Production in the United States is increasing, but it is not increasing at the same average rate as domestic consumption, nor is it probable that in the future domestic production will increase sufficiently to satisfy the demands of domestic consumption, but on the contrary, in the opinion of those best qualified to know, the peak in the curve of domestic production of crude petroleum will be reached in a comparatively few years, whereas the consumption of petroleum and its product will increase at a continually growing rate. This country, then, must turn, and as the increasing imports from Mexico indicate, is turning to other sources than the crude petroleum, produced in this country to make up the deficit between domestic production and domestic consumption of petroleum and its products,

Jun 1, 1920

By K. E. Stanfield

One of the initial projects under the oil-shale research and development phase of the Synthetic Liquid Fuels Act, Public- Law 290, 78th Congress, approved April 5, 1944, was a survey of oil shales of the United States for the selection of a site for an oil-shale demonstration plant. The oil shales were assayed by the conventional Bureau of Mines retort method proposed by Karrick and described by Guthrie in a more recent publication. From previous experience and that had in making these assays, it became evident that the assay method should be modified or replaced by a more satisfactory one. There are several outstanding objections to the Bureau of Mines oil-shale assay method: (1) the oil yields are frequently smaller than those obtained by other types of assay equipment and by commercial retorts; (2) the assayed oil yield represents only a portion of the organic matter in the shale, which under more favorable conditions, may, Jae converted, more completely into oil; (3) the retorting procedure is controlled mainly by trial-and-error methods; and (4) the assay requires approximately 6 hours for completion.

Jan 1, 1949

By Ralph Husack

The Bureau of Mines investigated the effect of gamma radiation on reactions between Pennsylvania anthracite and fluorine and chlorine. In the tests with fluorine about 90 percent of the coal reacted at 350° C to form volatile products whether or not irradiation was employed. Up to 0.8 ml of liquid products per gram of anthracite was collected. Among the 25 com-pounds indicated by gas chromatography, fluoroform and l,l-difluoroethylene were tentatively identified from their relative retention times and perfluoro-cyclopentane from its infrared spectrum. In addition, a clear, hard, wax, probably a fluorocarbon, was formed at 45° C in both the presence and absence of radiation. With chlorine there was no significant difference due to radiation, and preliminary tests indicated that the chlorine reacted more with the organic matter of anthracite at 200° C than with inorganic matter. At 400° C the results were inconclusive because of excessive corrosion in the reaction vessel.

Jan 1, 1966

By A. Wahib Khair

"This article first describes the impact of respirable dust on the health of miners in underground coal mines in the United States of America. Second, it identifies the major sources of dust generation, namely cutting tools in the road headings. Two surveys associated with cutting tools were made to determine the useful life of these cutting tools, and to determine the effect of cutting tool wear on productivity of the continuous miners. Third, this article presents the results of a series of experiments carried out in the Rock Mechanics Laboratories at West Virginia University in order to study: 3.1 the effect of cutting tool rate of wear on respirable dust generation, 3.1.1 the effects of rock materials on tool wear and respirable dust generation, 3.1.2 the effect of cutting tool geometric parameters on respirable dust generation, and 3.1.3 the effect of tip materials used in the cutting tool on respirable dust generation. Recommendations in regard to cutting tool design are also presented in this paper.Silica and coal dust are the two major elements affecting the health of underground miners. According to Lemen [1] approximately 1,500 men died due to breathing in silica dust in 1936 while tunneling through a mountain of mostly silica, near the town of Gauley Bridge, West Virginia. Coal dust resulting in lung diseases in one of the major health hazards in underground coal mines. The impact of black lung on miners, coal workers' pneumoconioisis (CWP), has ranged from 16,000 to 23,000 each year since 1982 [1].The trend for conventional mining to continuous machine cutting of coal, using more productive machinery, is inexorable. Intolerable level of dust generated at the face is an indication of inefficient coal/rock cutting by these machines. The federal goverment of the United States paid about 11.7 billion dollars in workmen's compensation to more than 470,000 miners with CWP [2]. Bieniawski and Zipf [3] reported that annual benefit payments were about 2 billion dollars. The enactment of the Health and Safety Act in 1969 in the United States triggered the initial investigation into coal cutting mechanisms and cutting tool designs.The surveys concerning the utilization of cutting bits and performance of continuous miners in underground coal mines were made in order to have first hand information about bit consumption and coal produ¬ction.Three types of used bits, commonly utilized cutting tools on continuous miners, were collected from different coal mines. The used bits were grouped into symmetrically and asymmetrically worn bits. Distribution analysis for weight loss and conical height loss was done. Details of the results are presented elsewhere [4], here the results are summarized briefly. The analysis shows that approximately 50% of the collected bits have worn asymmetrically, which shows that many bits do not rotate properly during cutting. Analysis of the distribution of bit wear showed that the degree of bit wear varied from one type to another and with mining conditions. On average, the weight loss of the used bits was 4% to 7% with a maximum of 31%. Correspondingly, the loss of the conical height was observed to vary between 11% and 23% with a maximum of 71%. Figure 1 shows typical data associated with some of the used bits."

Jan 1, 1998

Southeast Alaska's mining industry has come to life after nearly 50 years of relative dormancy. Commencement of operations of the Greens Creek Mine in 1989 marked a turning point in the industry as the first large scale mining operation in the region since closure of the Alaska-Juneau Mine in 1944. The Greens Creek Mine is now the nation's largest silver producer. Other large scale mining projects are now on the drawing board, including development of the Kensington Mine and reopening the Alaska-Juneau Mine, which could become North America's largest underground gold mine. The region's mining industry includes more than these large scale projects, however. For example, a significant level of mineral exploration occurs each summer in Southeast Alaska. In addition, mining operations in British Columbia and Yukon Territory are generating jobs and income in Southeast Alaska.

Jan 1, 1992

By S. J. Hussey

Since the discovery in 1935 by Adams and Holmes that certain synthetic resins exhibit ion-exchange properties, many applications of the ion-exchange process have been made. There are two general types of ion-exchange resins. Cation exchange resins adsorb cations from solution, and these in turn may be replaced by other cations adsorbed under certain conditions. 'Anion exchange resins adsorb acids from solution, and the anion of the acid may then be replaced by other anions. It is reported, however, that certain anion exchange resins have a low capacity for anions of weak acids without the necessity of acid adsorption either directly or as an intermediate step. The adsorbed ions may then be removed from the resins by elution with an appropriate solution, and the resin is prepared for the next adsorption cycle by regeneration with another solution. Sometimes one solution, is used to simultaneously perform the functions of elution and regeneration. The first and probably the largest application is in the field of water purification. Other applications have been made in the production of high-quality foods for human consumption, in the recovery of valuable substances from solutions, in the separation or fractionation of electrolytes, and in several other fields, each of which has its specific applications, variations, and possibilities. Ion exchange resins also have been highly useful in perfecting techniques of laboratory analysis and research.4/, 5/, 6/

Jan 1, 1948

On July 1, the Bonneville Power Administration announced a 25% power cutback because of lower than normal stream flow. In September, the Aluminum Company of America (Alcoa) announced plans to shut down one 23,000-ton-per-year potline at its Vancouver, Wash., primary aluminum smelter. Alcoa also announced that the last of four potlines at its Point Comfort, Tex., primary aluminum smelter would be restarted in October. A new 3-year contract was signed and workers at three Alcan Aluminum Ltd. primary aluminum smelters in Canada returned to work. It was estimated that it would take about 3 months before the smelters were operating at full capacity.

Jan 1, 1979

By H. W. Clair, E. V. Potter, M. J. Speedlove

"INTRODUCTION The behavior of particles in a sound field has long been of scientific interest since Kundt (1) 5/ made his classic experiments on some of the interesting effects of standing waves in cylindrical tubes. With the development of the electronic tube and its application to continuous generation of sound, experimental investigation of the Kundt tube was renewed (2). The more intense vibrations set up by a continuously vibrating diaphragm or rod produce even more striking effects than those observed by Kundt. Instead of the striations at the antinode produced by the stroked rod, then, wafer like barriers are formed at the antinodes, sometimes extending over the entire cross-section of the tube. Furthermore, it was observed independently by Andrade (3), Brandt, Freund and Hiedemann (4); and by investigators in the Bureau of Mines laboratories (5) that aerosols, such as ammonium chloride or tobacco smoke, could be flocculated quickly if passed through an intense sound field, particularly when a standing wave field was set up by a resonant enclosure. Because of its possibilities as a new means for removing suspended particles from dust-laden gaseous furance or smoke, the phenomena attending the behavior of suspended particles in a und field have been studied intermittently by the Bureau of Mines over the past decade.The first experimental work was done with a magnetostriction vibrator and a Hartmann air-jet generator as sound sources. It soon became evident that neither type was entirely satisfactory. Low mechanical efficiency is an inherent characteristic of magnetostriction generators, and the air-jet generator is difficult to control and does not permit accurate measurement of the acoustic output. The search for a suitable sound source led to the development of an electromagnetic generator, which is by far the most suitable for study of the effects of intensive high-frequency sound fields in gases (6)."

Mar 1, 1948

By C. H. Johnson

The Big Jim mine of the United Eastern Mining Co. is at Oatman, Mohave County, Ariz. Oatman is in the foothills on the western side of the Black Mountains, at an elevation of about 3,000 feet. It is on a paved highway about 30 miles west of Kingman, the principal distributing; center for mining supplies in the district, and 25 miles from Topock, en the Colorado River. Both latter towns are stations on the Santa Fe Railroad; Oatman has no roil connection. Mining conditions are typical of western Arizona; water is scarce, no mine timber is available locally, and the winters arc mild and the summers hot. The supply of a killed labor is usually adequate, but in 1933-34 it w not more than sufficient for the restricted operations. Wages have been $4.00 to $4.50 for miners. Electric power was supplied from Kingman and cost about 2.6 cents per kilowatt-hour.

Jan 1, 1935

By H. D. Jacobs

A process for recovering both iron and manganese from four manganiferous ores of the Cuyuna Range was evaluated. It comprised: (1) Low-temperature gaseous reduction to convert nonmagnetic iron minerals to magnetite and manganic minerals to manganous oxide, (2) acid leaching to extract manganese, and (3) magnetic separation to reclaim iron from the leach residue. Iron recoveries from the magnetic products ranged from 70 percent to 90 percent; manganese recoveries from leach filtrates ranged from 75 percent to 95 percent. Two ores, from the Hillcrest and South Alstead properties, yielded magnetic products considered adequate for use as blast furnace feed. Although good yields of manganese were attained on all ores, appreciable iron accompanied the manganese into solution. Previous work, however, has shown that this iron can be precipitated almost quantitatively under autoclave oxygen pressure with very little loss of manganese.

Jan 1, 1970

By Dale E. Wittmer

Nonoxide ceramic materials could substitute for high-temperature alloy steels containing imported critical and strategic materials such as cobalt, chromium, and nickel if their high-temperature properties can be improved. An important result of this substitution would be a reduction of the Nation&apos;s need for imports of critical and strategic materials. In this Bureau of Mines investigation, the primary objective was to produce high-purity u1trafine (particles <5 ~m equivalent spherical diameter (ESD)) alpha-silicon carbide (a-SiC) powders with improved high-temperature properties using the Bureau&apos;s patented turbo-milling process. A secondary objective was to determine the feasibility of using polymer mill construction materials as a means of eliminating metal contamination from the turbomill. U1trafine a-SiC powders with BET (Brunauer-Emmett-Te11er) surface areas from 30 to 35 m2/g (~0.06 ~m particle ESD) were produced in an all-polymer turbomi11. These high-purity powders (with I-pct Band I-pct C additions) hot-pressed to greater than 99 pct of their optimal density and exhibited properties commensurate with those of commercially available a-SiC. The most promising of the construction materials tested for the major wear surfaces of the turbomi11 was u1trahigh-mo1ecu1ar-weight (UHMW) polyethylene, a polymer thermoplastic.

Jan 1, 1984

By R. C. Buehl

An experimental iron blast furnace of 3-foot-diameter hearth, producing about 12 tons of metal per day, was operated for 2 weeks with various proportions of anthracite replacing a corresponding amount of coke. The furnace operated well with anthracite in amounts up to 40 percent of the total fuel and produced metal of uniformly low sulfur and normal silicon contents. An increase to 50 percent anthracite during two attempts resulted in poor operation and the charge hung in the s haft of the furnace. INTRODUCTION Anthracite production in Pennsylvania decreased from 84,400,000 net tons in 1926 to 40,600,000 net tons in 1952, and there was a further decline in 1953 to 30,900,000 net tons. Employment in the anthracite industry dropped from 165,000 men working an average of 244 days per year in 1926 to 57,900 working an average of 163 days per year in 1953,3/ which has naturally resulted in considerable unemployment in the region. The industry is actively engaged in promoting new uses for anthracite to increase the demand and thus improve economic conditions in the region. One possibility is the use of anthracite to replace part of the coke for smelting iron ore in blast furnaces. The tests in this report were made to determine whether this use of anthracite would be feasible.

Jan 1, 1955

By Kathleen M. Kowalski

This research explores the emergence of leadership in a crisis situation. The study by the U.S. Bureau of Mines focuses on three underground mine fires and the resulting evacuations. The subjects for this study are 48 coal miners, who evacuated the mines as part of eight escape groups, The subjects described their escape during an open-ended interview. Data were coded according to: (a) evidence of leadership behavior, (b) evidence of lack of leadership behavior, and (c) characteristics of the individual in each group who led the subjects out of the mine. During analyses, attributes of the leaders, who facilitated the escapes, were noted and compared as were instances of lack of leadership. The structure of the group leadership before the crisis was compared with the reality of the leadership during the crisis. Some groups experienced an apparent breakdown of leadership during their escape, while others witnessed the emergence of leadership. Consensus characteristics of the leaders, who emerged during these crises, are discussed and generalizations drawn. Research into leadership during emergency escapes is needed to provide information for training in prevention, escape, and rescue. The authors suggest questions for further investigation and topics for further inquiry into the area of leadership evolvement during crisis.

Jan 1, 1994

By Anil Mahyera

Towards the goal of achieving uniform-high-tensions in roofbolts to provide superior roof support[1-7] for extended periods, Terra Tek installed mechanical-anchor bolts in a mine in eight different ways -- under torque/thrust control with and without hardened washers, belleville washers and tension equalization; in a conventional manner with and without a hardened washer. The various bolt groups were analyzed in terms of their tension uniformity and mean tension levels. Installing the bolts accurately with ? a hardened washer under the bolthead, and ? proper torque/thrust control resulted in the mast uniformly tensioned bolts -- with a coefficient of variation of only 14%, an improvement of 3 times over a conventional installation. Also, these bolts maintained a high tension level -- 80% of the installation tension, compared to 50% achieved conventionally.

Jan 1, 1982

By S. S. M. Chan

The Bureau of Mines has investigated the structural aspects of shafts and support systems using the finite-element technique. In situ field measurements in deep, vein-type metal mines show that rock stresses are often higher in the horizontal direction than the vertical, and unequal in the horizontal plane. These data and laboratory and field-determined physical properties were used as input to analytical studies. Various design and construction parameters were investigated to deter-mine the effect on shaft stability. Rectangular shafts were studied in detail to determine the effects of applied stress ratio, shaft orientation and dimension, influence of interbedded quartzite and argillite, and rock fracturing. Various support systems were analyzed, including concrete lining, timber, and steel sets. Circular configurations were investigated to evaluate yield zones and liner thickness. Elliptical shafts and time effects were briefly evaluated to illustrate shape and time effects and demonstrate the methodology. It is shown that the magnitude, direction, and ratio of applied stress and rock mass anisotropy are keys to determining shaft stability. A realistic conceptual framework was developed with which to examine the rock and support interaction in deep mine shafts. Structural analysis techniques overcome some of the historical difficulties with shaft de-sign by defining the field data requirements and structural sensitivity of various design and construction parameters.

Jan 1, 1985