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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 Lawrence S. Darken

STAFF: Editor, Gerhord Derge Cornegie Institute of Technology Schenley Pork Pittsburgh 13, Pa. Editorial Assistant, M. A. Redmerski Production Editor, Otto T. Johnson THE METALLURGICAL SOCIETY: J. S. Smart, Jr., President; C. C. Long, Past-President; K. L. Fetters, Vice President; T. D. Jones, Treasurer; R. W. Shearman, Secretary. PUBLICATIONS COMMITTEE OF THE METALLURGICAL SOCIETY: C. L. McCabe, Chairman; H. L. Bishop, K. L. Fetters, J. J. Harwood, W. A. Krivsky, F. C. Longenberg, R. E. Lund, W. 0. Philbrook, L. L. Seigle, R. L. Smith, and F. L. Vogal. Review and selection of manuscripts is under the supervision of the following Publications Committees: Extractive Metallurgy Division: C. L. McCabe, Chairman; R. E. Lund, Vice-chairman; D. H. Baker, Jr., W. A. Krivsky, R. A. Lewis, Paul Qusneau, A. S. Russell, R, E. Shinkoskey, W. W. Stephens, and M. E. Wadsworth. Institute of Metals Division: L. L.Seigle, Chair-man, P. A. Back, J. J. Backer, l.l. Bessen, J. 0. Betterton, Jr., J. 8. Clark, R. S. Davis, A. E. Dwight, R. W. Fountain, R. B. Gordon, C. D. Graham, Jr., R. W. Guard, J. C. Gurland, E. L. Harmon, J. J. Hager, A. A. Hendrickson, M. Harmon, J. N. Hobstatter, H. H. Johnson, Jr., H. 5. Kolish, R. R. Nash, T. N. Rhodin, R. H. Richman, W. Rostokar, P. G. Shawmon, C. W. Spencer, L. Slifkin, J. K. Stanley, C. D. Starr, R. Steinitz, and H. C. Stumpf. Iron and Steel Division: H. L. Bishop, Chairman; 2. E. Boni, F. C. Langenberg, J. B. Wagstaff, and T. V. Wainwright. Published bimonthly by the American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc., 29 West 39th Street, New York 18, N. Y. Telephone: PEnnsylvania 6-9220. Subscription PetroleumEngineers,$30 per year for non-AIME members in United States and North, South, and Central America; 332, foreign; $5 for AlME members. Single copies, $4.00, single copies foreign, $5.00. The AlME is not responsible for any statement mode or opinion expressed in its publications . . . Copyright 1%1 by the American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc. . . . Registered cable address; AIME New York ..Indexed in Engineering Index, Industrial Arts Index, and Chemical Abstracts.. .Second class postage paid at New York, N. Y., and Ann Arbor, Mich. Volume 221, Number 4.

Jan 1, 1962

By R. Barany

This report contains the results of experimental work conducted by the Bureau of Mines to obtain the heats of formation at 298.15° K. of analcite, dehydrated analcite, lawsonite, anorthite, hexagonal anorthite, and leonhardite. Thermodynamic data for these minerals have applications in ceramics, extractive metallurgy, and particularly in geochemistry. Except for data on anorthite, no previous similar data existed. The present results will be a substantial aid in deriving the temperature-pressure-equilibrium relationships among these minerals. The heats of formation were determined by solution calorimetry, with hydrofluoric acid as the reaction medium. The results were expressed both in terms of the constituent oxides and in terms of the constituent elements. The heat of formation data were combined with related entropy values to obtain the free energies of formation at 298.15° K.

Jan 1, 1962

By Oliver C. Fursman

These investigations were conducted to determine conditions for recovery of nickel and copper from Funter Bay, Alaska, sulfide ore and recovery of nickel from nickel-silicate ore, Nickel Mountain, Riddle, Oreg. Samples of Funter Bay cupriferous and nickeliferous pyrrhotite ore, were treated by beneficiation, roasting, electric smelting of roasted are for matte production, chlorination, leaching, and sulfatizing roasting with subsequent leaching. Funter Bay and Nickel Mountain ores were smelted together to produce matte. Total sulfide flotation, followed by magnetic separation of the tailings to recover entrained nickel-bearing pyrrhotite, resulted in the highest nickel recovery in beneficiation tests on Funter Bay are. Overall beneficiation resulted in recovery of 98.5 percent of the copper and 95.4 percent of the nickel in the concentrate that contained 3.5 percent copper and 1.7 percent nickel.

Jan 1, 1962

By A. M. Gaudin

In the first place, let me thank you for inviting me to appear before you today to speak to you on "Mineral Industry Problems - Present and Future". It is a distinguished honor for me to have this opportunity, and I am highly appreciative of this distinction. The beautiful surroundings of Gatlinburg and the pleasantness of a summer occasion are a wonderful tonic for all of us, yet they should not blind us to the seriousness of our Industry's problems No doubt, because of my past appearances before members of the Society of Mining Engineers, at which I discussed wholly scientific topics, or research in the Applied Sciences, you may be expecting me to revert to these subjects. But I intend to venture in a field that is new to me, yet old to all of us, the field of Economics.

Jan 1, 1962

By E. C. Perkins

As part of a program for developing methods of using domestic titanium deposits, the Bureau of Mines investigated methods for chlorinating titanium slags prepared from titaniferous minerals by electrosmelting. Titaniferous slags were made from ilmenites in the following deposits: Valley County, Idaho; Trail Ridge, Fla.; Aiken, S. C.; and Maclntyre, N. Y.; titaniferous magnetite from Iron Mountain, Wyo., were also evaluated. The tests were made in two chlorinators, a 4-inch and a 36-inch unit. Preliminary testing was done in a 40-millimeter bench-type unit. Chlorine gas was contacted with a loose mixture of titaniferous slag and carbon at a high temperature to form titanium tetrachloride. The moving-bed system used in this work involved a downward movement of feed countercurrent to the chlorine flow, and residues continuously removed from the bottom of the reactor. The performance characteristics of these slags depended on their composition, which varied widely according to the geographic source of the ore. The results showed that all but two of the slags could be chlorinated as effectively as rutile, converting 70 to 80 percent of the titanium to the tetra-, chloride. The two slags that proved difficult were made from New York ilmenite and Wyoming titaniferous magnetite. These slags contained enough magnesium to cause clinkering, which necessitated that the bed be prematurely withdrawn before more than 70 percent of it could react. The iron content of the slags did not interfere with operating the chlorinators. The data from the 4-inch and the 36-inch units were in agreement on the relative amenability of the slags to chlorination.

Jan 1, 1962

By H. L. Burmeister

This is one of a series of publications by the Bureau of Mines dealing with mining methods and costs at representative operations in the United States. The report describes all phases of the mining methods for the open-pit operation and milling practices employed at the Vermont Asbestos Mines in Lamoille and Orleans counties, Vermont. A brief history of discovery and development of these asbestos deposits is given, and the ore deposits are described. Methods employed in exploration, sampling, and estimation of tonnage and grade are outlined. A breakdown of available cost figures is summarized in the last section. All asbestos ore produced in this area has been won by the use of surface-mining methods. Two quarries, the Lowell and the "C" Area, are in operation. The quarries combined are producing and the mill is processing approximately 3,500 tons of ore per 3-shift day The average 40,000 tons of crysotile asbestos fiber produced at this plant annually accounted for 96 to 98 percent of the total fiber produced in the United States in 1958. The mine is located (fig. 1) approximately 4 miles north of Eden Mills village on the southeastern flank of Belvidere Mountain (fig. 2).

Jan 1, 1962

By J. G. Donaldson

Nickel containing less than 0.01 percent of total metallic impurities was produced at the Rolla Metallurgy Research Center of the Bureau of Mines by electrodeposition from purified electrolytes. The first report on this research4 described purification of electrolytes by selective precipitation and by liquid-liquid extraction. This second report describes a procedure: or electrodepositing high-purity nickel from electrolytes purified by passing a nickel ammine solution through a column of an ion exchange resin. The nickel electroplated directly from the ammine solution without further treatment; a titanium cathode and two platinum anodes were used. The nickel deposit was dense, smooth, and adherent, and contained less than 0.001 percent each of cobalt, copper, and iron, and spectrographically detectable traces of aluminum, magnesium, and silicon. Nonmetallic impurities in the nickel metal were carbon and sulfur, each present in concentrations of less than 0.01 percent. The results of several experiments planned to purify solid nickel salts by zone refining are also reported. These salts, after purification, were intended for use in preparing electrolytes for deposition of high-purity nickel. Results were not encouraging so that the more promising ion exchange procedure was emphasized chiefly.

Jan 1, 1962

By R. P. Maloney

Since mining operations began in 1900, Government geologists and mining men have periodically recorded the presence of the minerals of mercury and antimony in the extensive gold placer deposits near Flat in the Iditarod district of the Yukon River region, Alaska. No serious effort was made to recover the cinnabar contained in the gold placer gravels, and there is no evidence that veins of cinnabar and stibnite exposed in the placer operations (as reported by the Geological Survey) were ever explored or developed. A large monzonitic intrusive, which is the dominant geologic feature of the immediate area, is believed to be the lode source of the valuable minerals in the placer deposits. In contact with the monzonite are argillite and quartzite, metamorphic products from the Cretaceous shales and sandstones.

Jan 1, 1962

By J. V. Batty

Radioisotopes of selenium (se78) and tellurium (Te123) were successfully employed by the Bureau of Mines as tracers in metallurgical research directed to developing improved methods for volatilizing these elements from low-tenor raw materials. Prior research, guided and controlled by conventional analytical methods, was seriously hampered by inconsistent selenium and tellurium analyses, by the slowness of the conventional chemical methods, and by the poor accountability of these volatile elements in test products. Methods were devised and evaluated for admixing the radioactive tracer with typical raw materials and then following the deportment of the selenium and tellurium by radiometric methods with occasional chemical analysis checks. These techniques were found unusually effective in (1) quantifying the completeness and the rate of volatilization of selenium and tellurium while heating the raw materials at different rates to different temperatures and (2) accurately tracing and quantifying the distribution of minute amounts of these volatile elements in the several products made by high-temperature treatment and in the several units comprising the experimental equipment.

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 Murray Jacobson

Facts obtained by the Bureau of Mines on the dust-explosion hazard in air of materials used in the plastics industry are presented for 313 samples studied in the laboratory. Information is given on ignition temperature of dust clouds and layers, minimum explosive concentration, minimum energy required for ignition, explosion pressure and rates of pressure rise, amount of inert dust required to prevent ignition and flame propagation, and, in some instances, on the limiting oxygen concentration in an atmosphere to prevent ignition by spark and by heated surface. The effects of particle shape, additives, and resin structure on explosibility are discussed. Relative explosibility of the materials is related to the ignition sensitivity and explosion severity and is denoted by an empirical index. Recognition of the degree of hazard will facilitate adoption of adequate measures for preventing ignition and explosion during manufacturing or processing.

Jan 1, 1962

By W. J. Boone

The Bureau of Mines has programmed for publication a series of Reports of Investigations of studies it has undertaken on low-temperature phase equilibria of several helium-bearing natural gases. This report is the second of a series of papers of the same general title; it is anticipated that additional reports of this series will be published. The advent of a helium conservation program and the prospect of production of helium by private industry, make it especially desirable to publish these data. This report describes phase equilibria related to a natural gas that is processed for helium at the Bureau's Exell Helium Plant (located about 35 miles north of Amarillo, Tex.). Carbon dioxide and water in the gas were removed before making the study; hence the data obtained are representative of the gas stream immediately after similar preliminary treatment in the plant process. Phase equilibrium data were obtained for conditions from -50° to -275° F. and from 100 to 500 p.s.i.a. Analyses of samples were made as follows: For a given run at a selected temperature and pressure, samples of the vapor and liquid phases were analyzed by mass spectrometer, and an additional sample of the liquid phase was analyzed for helium by means of special apparatus (7). 4

Jan 1, 1962

By Frank B. Fulkerson

Of the about 60 million pounds of aluminum used in the Pacific Northwest in 1960, 40 million pounds or two-thirds was used by 10 companies. One of these companies made airplanes and missiles; one manufactured roofing, siding, and tubing; three produced truck tractors, truck bodies, or truck trailers; two made architectural metal products; one made irrigation and industrial products; one was a general foundry; and one was a shipyard. These companies contributed to regional growth by developing markets outside the area; some have worldwide sales. Aluminum consumption increased at an average rate of 7 percent annually from 1954 to 1960. Airplane manufacture, formerly preeminent in aluminum use, no longer was in first place in 1960. By industrial group, the leading users were manufacturers of building products, 30 percent; airplanes and missiles, 22 percent; truck tractors, truck bodies, and truck trailers; 17 percent; general foundries, 5 percent; ships and boats, 4 percent; mobile homes, 4 percent; other transportation equipment, 3 percent; and irrigation equipment and all other products, 15 percent.

Jan 1, 1962

By Edwin E. Maust

In response to the ever- increasing demand for high temperature materials, the Bureau of Mines instituted a program for the study and development of superrefractories, One of the major tools obtained for use in this research was an image furnace of the double-paraboloidal mirror type. Although extensive theoretical analyses of solar furnace performance may be found in the literature, comparable detailed information on the double-paraboloidal-mirror image furnace has been nonexistent. This report presents an analysis based on an investigation undertaken to ascertain the limitations and characteristics of the furnace so that it can be used most effectively. The quantitative determination of the energy available at the image, the control of this energy by mans of a 60-inch iris diaphragm, and its variation with position and time relative to the heat source used have all been dealt with in detail. The quantitative results were obtained using a specially designed waterflow calorimeter and these measurements, in conjunction with the theoretical analysis, are used to present a fairly complete description of the furnace and its capabilities.

Jan 1, 1962

By Richard F. Hewlett

Engineers at the Bureau of Mines Denver Mining Research Center have been a research program investigating the theory and application of mine sampling. Part of this program is an investigation of the efficiency of sampling methods that involves development of sampling-method theory through simulating ore-deposit samples and assays, using - electronic digital computer. Theoretical developments are checked against actual ore-deposit sampling, assay, and production data by the commonly used polygonal and triangular methods of computing grade and tonnage of ore reserves. To speed the computing procedures, a program has been developed utilizing a medium-size digital computer for computing ore reserves by the polygonal method. This program calculates nine prismoids per minute at a total cost of $0.21 per prismoid. The complete program, written for an augmented IBM 650 computer, is described in detail; it can be used without change for computing ore reserves for a low-grade deposit. Modifications necessary to convert the program to compute ore reserves for virtually any other type of deposit or grouping of ore horizons also are given; however, the program is limited to using only vertical drill-hole data.

Jan 1, 1962

By R. Ward Stahl

Fire is still a scourge of the mining industry, although many precautionary measures have been and are being taken to reduce the incidence of fires and to combat them. Generally, the success of fire extinguishment is directly proportional to the speed of attack, and the speed of attack in turn is dependent upon the availability of materials and trained personnel. Preparations for firefighting are frequently neglected because they are considered emergency needs and do not contribute directly to coal production. Fire incites panic--a fact often overlooked--but such chaos can be minimized by training people in the use of equipment and procedures. Heat, smoke, and fumes hamper the approach to a fire; however, a relatively new technique of attacking fires with high-expansion foam may well contribute greatly to firefighting. The foam is transported to a fire and used at a considerable distance, thus permitting the firefighters to work more safely.

Jan 1, 1962

By K. E. Tame

The Bureau of Mines is studying possible modifications in conventional uranium ore-processing steps to confine and permit controlled disposal of radioactive wastes. A potential method of minimizing pollution from radio-active nuclides, principally radium 226, in uranium mill waste streams is to reuse the waste solutions within the mill. Such reuse of waste solution in the Kerr-McGee Shiprock-type process was investigated in the laboratory. The Shiprock mill employs a two-stage acid-leaching process for dissolution of the uranium, countercurrent decantation for liquid-solid separation and washing, and organophosphorus solvent extraction for recovery of the uranium and vanadium from solution. The simulated use of barren raffinate instead of fresh water in the mill circuit was carried through a laboratory campaign of 28 interlocked leaching, washing, and solvent extraction cycles. About 99 percent of the uranium and 91 percent of the vanadium were dissolved from the are, Washing efficiency in the thickener circuit averaged about 99.5 percent when the pulp was washed with enough barren raffinate and makeup water to recover 2.5 tons of pregnant solution per ton of ore. The only solution discarded was that contained in the washed and thickened leach residue. A buildup of salts due to recycling of solutions did not adversely affect operation of the washing circuit.

Jan 1, 1962

By H. P. LeVan

The aced for reliable reserves of the essential element, manganese, has been a continuing concern of the Federal Government for more than three decades. Because of the increasing vulnerability of outside sources of supply efforts have been intensified to find a means for beneficiating United States domestic deposits. The deposits of most interest would of necessity be near, or have access to, suitable transportation to processing plants. The Georgia manganiferous iron deposits represent some 10 million tons4 of ore readily available to southern iron and steel industries, if a manganese recovery process capable of functioning in the presence of large quantities of iron can be developed. In addition, a successful method for beneficiating the Georgia ore could produce a significant quantity of high-grade iron concentrate. The Differential sulfatization process developed 47 the Bureau of Mines5 seemed to be well suited for this application, particularly because it results in low concentrations of iron in the leach liquors with relatively complete extractions of manganese. In this process, manganese in the presence of iron is preferentially reacted with sulfur dioxide at elevated temperatures and subsequently extracted with water.

Jan 1, 1962