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By John J. S. Sebastian

A laboratory-scale investigation was made of the basic problems involved in developing a ceramic heat exchanger to operate at high temperatures for using nuclear heat from gas-cooled process-heat reactors. Technical data were obtained on transferring heat by forced-convection from helium to air in a single-tube vitreous-alumina heat exchanger. Coolant air was passed through the annulus parallel with, and either concurrently or counter to, the flow of helium inside the tube. The data obtained pertain to removing heat from the helium. Average inside film coefficients were determined at mean surface temperatures of 200° to 1,570° F., inlet-gas temperatures of 1,450° to 2,665° F., and Reynolds numbers up to 560. The gas-to-surface temperature ratios were varied from 1.05 to 7.6. The tabulated results are shown in the appendix at the end of this report. The film coefficients of heat transfer were correlated by taking into account the physical properties of the helium at the average fluid temperature. With experimental conditions pointing to a laminar flow, the Nusselt number was found to decrease as the ratio of gas-to-wall temperature was increased to a value of 3. However, within the range tested, gas-to-wall temperature ratios above 3 did not affect the Nusselt number, regardless of the value of the Graetz number. Thus, beyond this point any increase in this ratio ceased to influence the heat-transfer relationship.

Jan 1, 1962

By Donald W. Mitchell

Research shows that water neutralizes the explosion hazard of coal dust when present in sufficient quantity and when intimately mixed with the dust. The quantity of water required to neutralize coal dust and coal-rock dust mixtures is about equal to the limiting moisture adsorptive capacity of the dust; the adsorptive capacity increases with increase in the fineness and volatile content of the coal. Pools of water or high atmospheric humidity do not reduce the explosion hazard. Although wetted dust is less dispersible than dry dust, poor dispersibility cannot be relied on as the sole safeguard against explosion. Dust mixtures that contain water in excess of their limiting adsorptive capacity are dispersed and ignited by severe initiation sources. Pure coal dust adsorbs water with difficulty and retains water poorly; adsorption and retention is increased by the addition of rock dust the coal; the rock dust agglutinates wetted coal and assures that incombustible is present should drying occur. Therefore, it is advantageous to rock-dust wet areas in bituminous coal and lignite mines. When coal-rock dust mixtures are wetted and subsequently dried, the explosion hazard is about the same as for dust which was not wetted.

Jan 1, 1962

By W. W. Agey

The Bureau of Mines examined and tested the rhodonite deposits of the Silverton lead-zinc district, San Juan County, Colo., as a possible source of domestic manganese. Exploration and development work by several mining companies and preliminary reconnaissance of the area by Bureau of Mines engineers indicated the presence of extensive manganese resources in the form of rhodonite. This report summarizes the results of laboratory beneficiation tests made on samples of different type and grade material obtained from surface and underground exposures of seven veins in the district. Surface and underground examinations revealed the presence of several prominent veins that could be traced up to 2 miles for a single vein along the surface. The principal veins average about 50 feet in width and apparently carry rhodonite to considerable depth. Underground samples were taken from the Sunnyside, Silver Queen, Washington, Independence, and Scotia veins. Samples also were taken from surface exposures of the Sunnyside Extension and Hidden Treasure veins.

Jan 1, 1962

By Clyde L. Brown

The ignition source of fires and explosions in coal mines is sometimes difficult to explain because resulting widespread destruction often erases valuable evidence that might reveal the cause. However, through years of experience, investigators have been able to piece together enough evidence to establish the reasons and, thereby, have been equipped to recommend corrective or preventative measures. The pattern of hazards is not constant. It changes with the development of new practices and new equipment. Important among the new hazards to coal mining are those introduced by electricity. In addition to the dangers of electric shock, fires and explosions from heat and arcs, and premature blasts, certain others have developed as a result of stray electric currents from direct-current traction systems. The conventional direct-current power-distribution system in coal mines is conducive to electrolysis damage to mine tracks, metallic pipelines, grounded power conductors, and structures in a position to become conductors of stray currents. The voltage drop resulting from power demand on intentionally grounded power conductors and accidental grounds on insulated conductors are common sources of stray currents in coal mines. Uncontrolled electric cur-rents flowing through the earth and metallic structures can be a menace, and these contribute to the estimated $6,000,000,000 annual loss caused by corrosion. The purpose of this publication is to discuss some of the electrolysis hazards in the coal-mining industry and to outline corrective measures to alleviate them.

Jan 1, 1962

DOME MINES, Limited, is a gold producer situated in the Porcupine area of Ontario, 500 miles north of Toronto. During the year 1960, '71 4,600 tons of ore were milled, yielding gold bullion valued at $6,025,370. Prior to conversion to natural gas, an average of 3,200 tons of coal was consumed annually, one third of which was obtained from Canadian sources with the remainder coming from the United States. Due to the distances involved, the freight charges increased the pithead cost by as much as ISO per cent. Steam is generated at a central boiler plant and used for timber treatment, plant heating and process steam. Until August, 1960, steam was supplied during the winter months by two water tube coal-fired boilers, each rated at 200 boiler horsepower at 100 per cent output. Steam requirement was as high as 150 per cent of boiler rating in the colder periods. The summer load was

Jan 1, 1962

By Richard F. Hewlett

The purpose of this Bureau of Mines paper is to provide the mineral industry with current information on high-speed data processing and to illustrate how some of these techniques can be applied to the industry. The need for applying these techniques is generally recognized, but not much information is readily available on specific applications. This paper briefly describes high-speed data processing and reduction equipment in an effort to familiarize the reader with the functions of the equipment. A list and explanation of some of the possible applications of high-speed data processing for the mineral industry are included. A few of these applications are illustrated by the use of specific examples of existing computer programs or processing methods, including their calculation times and costs. Some of the programs cited herein were developed by the author at the University of Arizona for a Masters thesis in mining engineering. When a reference is made to a specific computer, the reference is given to make the information that is being presented as factual as possible; most of the manufacturer's equipment that is mentioned in the references was available at the University of Arizona, and no specific endorsement of that manufacturer is intended.

Jan 1, 1962

By Michael G. Zabetakis

The spillage of liquid diethyl ether in rooms at floor level and 3 feet above the floor resulted in flammable vapor-air mixtures in the immediate vicinity of the exposed liquido The liquid temperature was found to decrease by as much as 35° C., with a resultant decrease in vaporization rate. A search of the literature yielded numerous references to unstable peroxide (residue) formed by the autoxidation of ether. Such residues appear to constitute an explosion hazard in the condensed state.

Jan 1, 1962

By Sara Jane Boles

In recent years the demand for products of greater refractoriness has placed an ever-increasing emphasis on ceramic materials, including the metallic oxides. Magnesia (MgO) is one of the most important of these oxides, exhibiting, as it does, high electrical resistivity, high slag resistance, and a melting point of 2,800° C. However, magnesia has a tendency to hydrate in the presence of water and to volatilize above 1,500° C. in certain kiln atmospheres and has a comparatively low resistance to thermal shock. Because of these disadvantages, the previously listed advantages inherent in this material have been largely overlooked, and research on magnesia has lagged behind that on oxides such as alumina and zirconia. This bibliography has been prepared in an effort to present to Government and industry a comprehensive picture of the prospects for greater utilization of magnesia as a refractory material in future research. To provide as selective and accurate a collection as possible, the references included cover magnesia in a pure state, not as an additive or in combination with other materials. However, several references discuss the effect of minor impurities (less than 5 percent of the total) on the properties of magnesia, as these papers are considered to be of special importance. A few references to articles on forming techniques are also included, as they are valuable additions to the overall treatment of the subject. The processes used in obtaining and refining the raw materials are adequately covered in earlier publications and are excluded. A number of references are omitted as being of questionable value in enhancing the cumulative study of pure magnesia as an ultra-high-temperature refractory material.

Jan 1, 1962

By Robert F. Stewart

The oxidation of structural materials at high temperatures in gas-cooled systems can be greatly retarded by the addition of small amounts of hydrogen to the inert coolant. In experimental equipment for gasifying coal with heat transferred by helium, the oxidation of graphite and metals (molybdenum, tungsten, and certain stainless steels) by trace impurities in the coolant helium was virtually eliminated by adding 0.1 to 1.0 percent hydrogen. The reaction of hydrogen with praphite does not preclude its use to retard oxidation; at 2,400° F. only 0.2 pound of graphite per square foot per year is lost for each percent of hydrogen in the helium. The addition of hydrogen appeared to prevent the mass transfer of carbon often associated with oxidation of graphite, without causing noticeable embrittlement of stainless steels and molybdenum or other damaging effects. This method has been tested in precision gas-recycle systems and applied successfully for more than a year in a pilot-scale unit operating at 250 pounds per square inch gage and 2,400° F. It is now used routinely and can be applied to many gas-cooled systems operating at high temperatures.

Jan 1, 1962

By Sidney Katell

Philippine laterite and serpentine ores can be utilized in an electric furnace operation to produce both a steel ingot and a ferronickel product. Figure 1 is a schematic interpretation of a plant in which laterite and serpentine ores are processed separately to obtain both ferronickel and steel as products. A relationship of estimated capital requirements and probable returns has been established in this study for a plant of this type. No attempt has been made to evaluate the risks involved in commercial operations. At such time that the project might be constructed and placed in operation, changes in the costs of material, labor, and power may materially affect the profitability aspects of this study. One of the uncertainties involved in the economic evaluation is the cost of mining, handling, and shipping the ores. It is on this basis that the cost of ore delivered at the plant is assumed to be variable at $3, $5, and $7 per net ton (dry basis). For all other costs a plant site at Iligan City, Philip-pine Islands, has been assumed in preparing the economic characteristics for a plant that will process 2,000 tons4/ of ore per day. Results of the study, for the 2,000-ton plant, with all monetary values expressed in terms of United States currency (Philippine peso valued at $0.50), are summarized as follows:

Jan 1, 1962

By Howard P. Hamlin

This Bureau of Mines report is concerned with the testing procedures for evaluating clays, shales, and slates for lightweight aggregates using the rotary-kiln method of production. To meet the increasing demand for light-weight concrete, rapid, accurate methods for appraising raw materials for light-weight aggregate are needed. Preliminary tests were made on samples of clay, shale, and slate, using laboratory equipment, and the data were used to establish operating conditions for pilot-plant-size rotary-kiln tests. Lightweight concrete was made from the processed aggregates and the properties determined. The results show that the laboratory data can be used to guide rotary-kiln testing, and, with the exception of sampling, a complete appraisal of a raw material for lightweight aggregate concrete can be made in 3 days by the methods described in this report.

Jan 1, 1962

By Clarence Karr

THE BUREAU OF MINES is investigating methods for upgrading tar produced by the low-temperature carbonization of bituminous coal. This survey was undertaken to compile information needed for identifying the ether constituents of low-temperature tar. Physical properties are listed for 1,024 aromatic ethers. The compounds include cyclic and noncyclic, polyfunctional and monofunctional ethers with oxygen joined directly to either one or two aromatic rings. Alkyl groups up through butyl are included. The compounds are divided into 37 groups ranging in complexity from alkoxybenzenes to dibenzopyrans. Compounds containing aromatic ether groups are important constituents of the neutral oxygen components of low-temperature tar. For example, at Morgantown, W. Va., the Bureau of Mines has identified and determined the amounts of benzofuran, 2-, 3-, 5-, 6-, and 7 -methylbenzofuran, diphenyl ether, dibenzofuran, 2,3-dimethyldibenzofuran, and two other dimethyl-dibenzofurans in the neutral oil from a low-temperature bituminous coal tar (103, 104).3

Jan 1, 1962

By Paul Meadows

This Bureau of Mines report presents operating practices and results of pressure maintenance and secondary recovery by water injection or by water injection supplemented by gas injection. Particular emphasis is placed on the results of water injection, which is the principal oil-recovery method employed in projects covered by this report. No attempt is made to study gas-injection projects or operations that are considered water-disposal projects. Also, this report does not include water-injection projects that have not been in operation long enough to evaluate results. Figure 1 is a map of north Louisiana showing the geographical locations of the projects included in this report. Most of the data used in this study were supplied by unit operators, operating companies, and the Louisiana Department of Conservation. Reservoir information and recovery data are generally those supplied by the operators, but include revisions where deemed necessary.

Jan 1, 1962

By W. H. Tomlinson

This publication presents the basic text for a 20-hour accident-prevention training course developed for supervisors by the Federal Bureau of Mines. During the past 2 years, the course has been used by the Bureau in teaching more than 300 groups of coal-mine supervisors-men whose responsibility is twofold: To manage in production and maintenance phases of coal mining and to guide their men along paths of safety. This is a handbook for teaching teachers. In this handbook will be found references to safety practices followed by companies that consistently have low accident records. These companies credit their outstanding performance to the adoption and faithful observance of accident prevention by supervisors and workers alike on a wholesome, cooperative basis. Teaching safety to workers involves both on-the-job and classroom-type instruction. If such training is to be permanently effective, it must be reinforced consistently on the job by the immediate supervisor of the worker. This publication is intended to provide such a supervisor with the motivation to provide such follow-up and shows how he can accomplish it effectively.

Jan 1, 1962

By George C. Branner

This circular is concerned with eight nonferrous scrap metals as they generated, collected, prepared, and consumed in California. Brief reference also is included with respect to Nevada and Hawaii. Four of these scrap metals - copper, lead, aluminum, and zinc - are of major importance and make up about 95 percent of the total value, whereas the remaining four - antimony, magnesium, nickel, and tin - make up the remaining 5 percent. For convenience, the subject matter is divided into three parts, (1) Data with respect to the collection, preparation, and marketing practices that are common activities to all the nonferrous scrap metals; (2) separate discussions and statistical data with respect to each of the eight nonferrous scrap metals in California; and (3) data with respect to Nevada and Hawaii.

Jan 1, 1962

1. BOYD, JAMES. Statement on the Investigation of Natural Resources. Hearings before National Re-sources Economic Subcommittee, Committee on Public Lands, U.S. Senate, 80th Cong., 1st sess., on Investigation of the Factors Affecting Minerals, Fuels, Forestry, and Reclamation Projects, May 15, 16, and 20, 1947, pp. 125-131. 2. BUCH, J. W., HENDRICKS, T. A., AND TOENGES, A. L. Statement on the Investigation of Natural Resources. Hearings before National Resources Economic Sub-committee, Committee on Public Lands, U.S. Senate, 80th Cong., 1st sess., on Investigation of the Factors Affecting Minerals, Fuels, Forestry, and Reclamation Projects, May 15, 16, and 20, 1947, pp. 231-235. 3. CONGRESS, U.S. An Act to Provide for the Establishment and Operation of a Research Laboratory in the Pennsylvania Anthracite Region for Investigation of the Mining, Preparation, and Utilization of Anthracite, for the Development of New Uses and Markets, for Improvement of Health and Safety in Mining, and for a Comprehensive Study of the Region to Aid in the Solution of Its Economic Problems and to Make Its Natural and Human Resources of Maxi-mum Usefulness in the War Effort. Public, No. 812, 77th Cong., 2d sess. (S-357), ch. 764, approved Dec. IS, 1942, 2 pp.

Jan 1, 1962

The Tenth International Conference of Directors of Safety in Mines Research was held in the United States from September 28 through October 2, 1959, at Hotel Webster Hall, Pittsburgh, Pa. The Conference was organized by the Federal Bureau of Mines. In accord with the program outlined at the Ninth Conference (1956, Heerlen, Holland), the papers submitted dealt with the following three subjects: 1. Safety of coal mine explosives 2. Explosion hazards in mines 3. Ignition and fires in mines Seventy papers were presented. There were eight technical sessions followed by an extended tour of the Bruceton facility of the Bureau of Mines on October 2. Simultaneous translation was provided in the three official languages of the Conference--English, French, and German.

Jan 1, 1962

By Gailen T. Vandel

El presente texto describe la historia, geología, exploración, actividades de explotación como parte de la construcción de la planta de beneficio en la Bahía de San Nicolás, Marcona. Dicho proyecto contempla una ampliación del la planta de chancado y almacenamiento de la mina, así como la faja transportadora de bajada a San Nicolás y red de carreteras. Asimismo se incluye la planta eléctrica Diessel y transmisión, el muelle y zona abycente, la expansión de esta planta para el tratamiento del chancado, la planta de la peletización y la planta térmica. Con la implementación de estos elementos a la planta de Marcona, se convertirá a la región en uno de los centros industriales de mayor importancia en Sudamérica.

Jul 20, 1961

By Paul L. Campbell

Investigations by the Federal Bureau of Mines of methods of upgrading tar obtained by low-temperature carbonization of lignite showed that ß,ß?-oxydipropionitrile, ß,ß?-iminodipropionitrile, and ß,ß'-thiodipropionitrile were effective solvents for extracting aromatics (aromatic hydrocarbons plus polar compounds) from coal-tar neutral distillate fractions. Batch extraction showed that these solvents extracted approximately the same percentage of aromatics from various neutral oil fractions boiling between approximately 170° and 350° C. In continuous countercurrent extractions using oxydipropionitrile and iminodipropionitrile, approximately 30 to 35 vol.-pct, and 65 to 70 vol.-pct, of the aromatics in 170° to 350° C. neutral distillate oil were extracted at room temperature when solvent-to-oil ratios were 2:1 and 12:1, respectively. As the concentration of aromatics in the neutral distillate oil fraction decreased, the capacities and, to some extent, the selectivities of these solvents for the remaining aromatics decreased. Aromatics were isolated from the extracts and the solvents recovered by washing the extract fractions with a low-boiling paraffinic hydrocarbon such as heptane, using hydrocarbon-to-extract ratios of at least 2:1. The heptane wash removed most of the aromatics but only part of the polar compounds (compounds containing oxygen, sulfur, and nitrogen) from the extracts. The recovered oxydipropionitrile and iminodipropionitrile, containing polar compounds, were effective in extracting aromatics from neutral distillate oils. The contaminated solvents showed essentially the same capacities and selectivities as the pure solvents.

Jan 1, 1961

By Miles B. Royert

Crude Minnesota taconite was charged in the Bureau of Mines experimental blast furnace so that smelting characteristics of such highly siliceous raw materials could be studied and smelting costs compared with those of a standard Mesabi ore. The Bureau recognized that the highly siliceous nature of the crude ore and its relatively low metallic content would be serious economic deterrents to commercial use of the raw taconite, but compensating factors would be low capital investment in production facilities, large tonnage available on short notice, high recoveries of iron, and low delivered cost. Crude taconite smelted readily in the experimental blast furnace. Coke consumption per ton of metallic product was very high, compared with the average established requirements for smelting normal grades of metalliferous raw materials. Slag rates were also inordinately high. Metal quality was erratic as to silicon, and sulfur contents were objectionably high.

Jan 1, 1961