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By E. G. Davis

The Bureau of Mines investigated gaseous direct reduction of low-grade iron ore concentrates in a continuous fluid-bed reactor. These studies were made in a 4-inch diameter fluid-bed reactor using hydrogen alone, and oxygen-or air-reformed natural gas as the reductants. The percent reduction is directly dependent on the mole ratio of hydrogen in the reducing gas to the oxygen associated with the iron oxide in the ore. Two-and three-stage fluid bed tests were simulated by repeated continuous tests. The results showed that percent reduction of the final product was dependent on the mole ratio of the quantity of hydrogen in the gas of each stage to oxygen in the iron oxide of the initial ore feed. Reduction as high as 87 percent in the single stages and as high as 94 percent in the multistages was obtained when either hydrogen or reformed natural gas was used as the reducing gas. Magnetic separation and concentration of the highly reduced fluid-bed product yielded a high metallic iron concentrate analyzing 85 percent total iron and 80 percent metallic iron with total iron recovery as great as 90 percent. Agglomeration of the high-grade metallized concentrate produced hard pellets analyzing 85 percent total iron and 78 percent metallic iron. Green pellets, with good strength, were made without any binder in a drum pelletizer. Direct melting of the high-metallic fluid-bed product in a basic lined arc furnace produced a nearly pure iron which contained 0.09 C and 0.01 P with 95 percent recovery of the metallic iron in the metal.

Jan 1, 1972

By Harry V. Makar

As part of a continuing research program for conserving domestic mineral resources, the Bureau of Mines is investigating new and improved scrap identification techniques to improve sorted mixed scrap purity. This report focuses on various classes of wrought and cast copper alloys produced with recycled scrap. Based on a survey of the literature, principal alloys, such as the brasses and bronzes, are examined with respect to impurity elements and their effects on metallurgical behavior. Effects of elements such as lead, antimony, iron, chromium, and aluminum are discussed. The metallurgical effects described include hot shortness, fire cracking, and undesirable phase transformations.

Jan 1, 1985

By Martin H. Rogoff

This publication combines a critical review of the literature on the microbiology of coal with an introduction to those areas of microbiology related to studies of coal as a biological material. The attack on coal by microorganisms as yet remains doubtful. Only the low-rank coals contain an indigenous microbial flora, and even these organisms are not peculiar to coal, but are common soil and water forms. No experimental data have as yet been presented, either in the literature or in the present work, which unequivocally demonstrate the oxidation of coal by microorganisms. Reasons for the resistance of coal to such attack, including insolubility, physicochemical structure, steric hindrance of enzyme action, and the presence of antibiotic materials in coal are discussed. Microorganisms do attack large aromatic molecules and the mode of oxidation of aromatic ring systems by bacteria is presented. Well-defined pathways are known for the oxidation of polycyclic compounds with one to three rings, and these paths with their key intermediates are described and related to the possible oxidation of coal.

Jan 1, 1962

By John C. Machisak

INJURY and employment figures for nonmetal mines and mills in 1959 are presented in this publication. Data for nonmetal mines are presented separately from those for nonmetal mills. The Bureau of Mines is authorized to send questionnaires to the nonmetal mining industry each year requesting their voluntary submission of injury experience and employment data. The voluntary response to these requests has contributed greatly toward the promotion of safety in the industry, and every effort has been made to make the information as complete as possible.

Jan 1, 1963

By John B. Knaebel

This paper is one of a series being prepared by the Bureau of Mines on mining methods and costs at various mines in the United States, Canada, and Mexico, and is a description of practice at the Edwards mine of the St. Joseph Lead Co. ACKNOWLEDGMENTS The cooperation and assistance of the officials of the St. Joseph Lead Co. in permitting publication of this paper and providing every facility for its preparation are gratefully acknowledged. Especial thanks are extended R. J. Mechin, manager, R. F. Mitchell, mine captain, and J. S. Brown, geologist, for their generous aid, and the assistance of W. H, Weijola, mine engineer in assembling some of the illustrations is deeply appreciated, The helpful suggestions of C. F. Jackson, principal mining engineer, U. S. Bureau of Mines, are gratefully acknowledged.

Jan 1, 1932

This Bureau of Mines report and its companion report (Information Circular 9142) have been prepared to assist in the preparation of prefeasibility type estimates for capital and operating costs of beneficiation of various types of mineral occurrences using current technology. The handbook provides a convenient costing procedure based on the summation of the costs for the unit processes required in any particular mining or mineral processing operation. The costing handbook consists of a series of costing sections, each corresponding to a specific mineral processing unit process. Contained within each section is the methodology to estimate either the capital or operating cost for that unit process. The unit process sections may be used to generate, in January 1984 dollars, costs through the use of either costing curves or formulae representing the prevailing technology. The mineral processing handbook includes individual cost estimation sections for unit operations associated with comminution, beneficiation, solid-liquid separation, hydrometallurgy, and special applications as well as infrastructure and plant general and administrative costs. When using this system for estimating cost data for a mineral processing facility or for checking or verifying processing costs from an existing facility, a minimum amount of background information is necessary.

Jan 1, 1987

By M. J. Jackson

MIGRATOM is a third-generation PC-based computer program developed by the U.S. Bureau of Mines for geophysical tomography. Like its predecessors, BOMTOM and BOMCRATR, MIGRA TOM was developed to enable users to address a variety of mining-related problems by mathematically reconstructing the distribution of physical properties in a rock mass, using measurements of travel time or amplitude of wave energy propagated through the rock mass. Examples of applications include lithologic characterization, fracture detection, fluid monitoring, stress evaluation, and blast assessment. The resolution and accuracy of tomographic reconstructions generally depend very strongly on the geometry of source and receiver locations. In many practical applications, such as cross-borehole tomography, limited coverage results in nonunique reconstructions. MIGRATOM follows the precedent of BOMTOM and BOMCRATR in allowing the user to constrain the inversion, in order to reduce the nonuniqueness problem. A new approach to application of constraints implemented in MIGRATOM is based on fuzzy logic techniques. Refraction of wave energy is modeled in MIGRATOM using an approach based on Huygens' Principle. Propagation of a continuous wavefront is modeled as a constructive interference phenomenon, which obviates the shadow-zone problem that affects conventional ray-tracing calculations. MIGRATOM has been tested with both synthetic and field data sets.

Jan 1, 2010

By Kenneth Eilerts

The development and operation of "combination wells"5/ have created new and unusual problems, many of which can he solved only if information is available concerning the properties of the fluids produced. Data as to the characteristics of the fluids at the relatively high pressures that exist in the reservoirs are especially important, and there is growing economic concern to know what part, if any, of the liquid recovered at the surface was liquid in the reservoir, As an extension of this problem, it is important to know, whether liquid will be formed in the reservoir as a result of isothermal retrograde condensation when the reservoir pressure is reduced. The pressure range of such condensation, if it occurs, is significant in the design of gas-recycling plants for maintaining reservoir pressures. In connection with the operation of such plants, it is particularly important to know how pressure and temperature will affect the yield of the liquid phase and the composition of the gas to be returned to the reservoir. It has not been possible to predict the behavior of these fluids that have high ratios off gas to liquid by comparing them with the behavior of low gas-liquid ratio fluids at identical pressures and temperatures. Such comparison fails because the proportions in which a component will be distributed between the phases of a system at any given temperature and pressure depend increasingly on the composition of the mixture as the critical temperature and. pressure of the system are approached. Because many combination wells are producing from reservoirs that have temperatures near the critical point, experimental date on the properties of the Fluids under reservoir conditions are particularly important at this time, To meet the immediate requirements of the industry for such experimental information, an equilibrium cell has been constructed at the Petroleum Experiment Station of the Bureau of Mines, Bartlesville, Okla. When adequate experimental date have been accumulated, it may be possible to make dependable estimates of the phase relations for high gas-liquid ratio fluids at the pressures anti temperatures characteristic of "combination-well? reservoirs.

Jan 1, 1940

By Oliver Bowles

Granites are classed as igneous rooks; they have been formed by the solidification of rook magmas or Solutions from deep within the earth. It is an almost invariable law of nature that mamas which cool quickly form fine-brained or glassy rocks, while those that cool slowly are completely crystallized and are coarser-grained. Granites, being of the latter class, are regarded as having attained their solid form at considerable depth below the surface under conditions of high temperature and pressure. The constituent minerals crystallized out slowly, the crystals interlocking with one another. The great depth of overlying rocks that must have been present when crystallization took place has been removed by erosion over large areas on the surface of the earth in consequence of which granites appear at or near the surface in many localities.

Jan 1, 1930

By Forrest T. Moyer

INJURY experience in the metal and nonmetal mineral industries during 1964 was better in rates of occurrence but worse in severity rates than in 1963. The frequency rate of injuries per million man-hours was improved at metal mills, nonmetal mines, and sand and gravel operations, and was virtually unchanged at metal mines; however" the rate of occurrence of work injuries at nonmetal mills, stone operations, nonferrous reduction and refining plants, and slag plants was higher than in 1963. The severity rate of injuries during 1964, data for which are presented for the first time in this chapter, was better at metal mills, nonmetal mines, stone operations, and slag plants. However, the severity rate was worse at metal mines, nonmetal mills, sand and gravel plants, and nonferrous smelters.

Jan 1, 1965

By W. T. Reid

A shortage of anthracite for home heating indicates the necessity of using other fuels for this purpose; low-volatile bituminous, or "soft" coal is the most feasible supplementary fuel, either burned alone or when mixed with anthracite. Comparison of Bituminous Coal and Anthracite Whereas anthracite is clean, burns without smoke, and requires little attention, bituminous coal is dusty, tends to burn with a smoky flame, and forms coke in the fire pot that must be broken up to maintain a continuous high output of heat. When properly fired, however, bituminous coal responds more quickly than anthracite to changes in damper settings and consequently can supply more heat in a short time. It is generally less expensive and usually contains less ash than anthracite.

Jan 1, 1943

By Wilbert J. Huff

The organization of the Explosives Division has been outlined in two preceding publications., The activities of the various units for the fiscal year 1939 are described hereafter: I. INFLAMMABILITY OF GASES AND VAPORS DETERMINATION OF EXPLOSION HAZARDS OF COMBUSTIBLE GASES AND VAPORS IN MINES AND INDUSTRIES (a) Determination of Limits of Inflammability of Gases and Vapors The following hitherto unpublished limits of inflammability were determined during the past fiscal year.

Jan 1, 1939

By Wilbert J. Huff

The organization of the Explosives Division has been outlined in two preceding publications.3/ The activities of the various units for the fiscal year 1939 are described hereafter: I. INFLAMMABILITY OF GASES AND VAPORS DETERMINATION OF EXPLOSION HAZARDS OF COMBUSTIBLE GASES AND VAPORS IN MINES AND INDUSTRIES (a) Determination of Limits of Inflammability of Gases and Vapors The following hitherto unpublished limits of inflammability were determined during the past fiscal year.

Jan 1, 1939

By I. D. Schleicher, L. H. Rorden, F. B. Curry, T. C. Moore

The purpose of this program is to extend electromagnetic (EM) techniques for use in locating miners trapped in mines as deep as 1000 m. A previously developed EM system is considered adequate for use at mines less than 300 m deep where it has a probability of detection of 54%. A system for deep mines must keep underground equipment simple, and use extremely low frequencies (ELF), sensitive receivers, and noise cancellation. The proposed location method, developed by Develco for other applications, is based on vector field measurements from two or more static sensors and computation of source location by iterative techniques. During Phase II, very sensitive search coil sensors were built and used in a separate test to verify the feasibility of atmospheric noise cancellation. A "Breadboard" location system version without cancellation, which is a fieldable test bed to evaluate receiving and location functions, was tested and supplied. Very good results were achieved from the first in-mine test with the transmitter at a depth of 380 m. It is expected the results of this work, and additional evaluation tests in the future, will be used to define the requirements for a prototype operational system.

By J. F. McIlwain

The Bureau of Mines has investigated fumes generated by selected welding electrodes used in mines in order to help determine their relative health hazard potential. Fumes were generated and collected in an enclosed chamber for subsequent generation rate and chemical constituent determination. Shielded metal arc electrodes from the following groups were tested: AWS types E308-16 and E310-16 stainless steel, ECoCr-A Co-Cr hardfacing alloy, ENiCr Ni, an Mn-Cr buildup alloy, E7018 carbon steel, and EII018-M low-alloy steel. Flux-cored wire electrodes of this last group also were tested. Fume generation rates and the chemical composition of the fumes were measured. From these data, exposure in-dices were determined, which give a relative measure of the health hazard potential of using the electrodes. The effect of welding onto build-up alloy layers on the fume composition also was examined for five of the higher alloy groups.

Jan 1, 1987

By Ernest A. Curth

The Bureau of Mines and Old Ben Coal Co. concluded a cost-sharing contract in 1975, the objective of which was to demonstrate the Herrin No. 6 coalbed in southern Illinois can be mined safely by longwall methods. Under the agreement, three longwall panels are to be mined at Old Ben No. 24 mine. A premining investigation laid the groundwork for specifying a roof-support system designed to control hazardous ground. Old Ben Coal Co. and Bureau engineers selected lemiscate-type roof shields. A rock mechanics program and geological mapping provide early warning capability and criteria for future equipment design. The effect of mining on the surface was monitored by a surface survey to develop subsidence-prediction criteria for the Illinois coal basin. The first of the three longwall panels started up in September 1976 and was completed in May 1977. The major adverse condition was the occurrence of limestone concretions, called coal balls, in massive pods. The shields provided adequate roof control even in faulty ground. Operation of the second panel started on August 1, 1977, following panel-to-panel transfer of the equipment. The accident rate was low.

Jan 1, 1978

By Peter Grandone

Bureau of Mines engineers engaged in studying stimulative methods of recovering oil have been making a series of tests on the effectiveness' of methods that may be applied in water flooding oil-bearing sandstones. The report gives the test procedures and results of a study of the rates and pressures used for injecting water into several sandstone formations in the Mid-Continent fields for the purpose of learning more about the mechanics and efficiency of the flooding process and to provide useful information for operators of water floods in this area.

Jan 1, 1949

By Oliver Bowles

Sandstone, a widely distributed siliceous sedimentary rock, is the third most popular building stone in the United States. It is formed by the breaking down of preexisting rocks by weathering, subsequent segregation of the detrital quartz grains into discrete deposits by the sorting action of water or wind, and finally cementation of the quartz sand into a coherent rock. The homogeneity and resistance to weathering of the resultant sandstone make it suitable for exterior construction. Its excellent wearing properties explain its popularity for flagging and stair treads. However, quarrying and dressing methods and costs are adversely affected by the abrasiveness and hardness of sandstone especially as compared to limestone.

Jan 1, 1963

By John C. Holtz

Interest in the possibility of using Diesel6/ engines for haulage power in mining and tunneling is increasing in the United States, owing largely to the reported successful use of Diesel locomotives in European coal mines and to the comparatively recent development of automotive Diesel engines in this country. The extent of this interest has been evidenced to the Bureau of Mines by numerous requsts for information as to the factors that must be considered if Diesel engines are to be used safely underground.

Jan 1, 1940

By John C. Holtz

Interest in the possibility of using Diesel6/ engines for haulage power in mining and tunneling is increasing in the United States, owning largely to the reported successful use of Diesel locomotives in European coal mines and to the comparatively recent development of automotive Diesel engines in this country. The extent of this interest has been evidenced to the Bureau of Mines by numerous requests for information as to the factors that must be considered if Diesel engines are to be used safely underground.

Jan 1, 1940