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By R. Wang, N. J. Grant, B. C. Giessen

By crystallographic and X-ray methods, the existence and isonzorphism of Ti3Rh5 and Hf3Rhs were confirmed. Both phases are of the orthorhombic Ge3Rh5 type; lattice parameters and refined positional parameters are given. The structure is related both to the filled-up NiAs-B8 and Cu-AI types. An analogous phase with zirconium does not exist; the effect of ternary substitutions for titanium ad hafnium suggests a size factor limit to be active. A recent survey of phase diagrams of the T4 metals titanium, zirconium, and hafnium with the T, noble metals rhodium and iridium indicated the existence of the A3B5 phases Ti3Rhs, ZrsRhs, and HfsRhs. Ti3Rhs and Hf3Rh5 were found to be isostructural, based on the line-rich powder patterns which had not been analyzed. Zr3Rh5 was considered to have a substructure of the NbRu type (orthorhombically distorted B2-CsCl type).&apos; Because, in combinations with other transition metals, hafnium and zirconium are generally more likely to form isostructural phases than hafnium and titanium (with the significant exception of the Ti2Ni-"E93" type phases based on T4 metals2), the reversal of this relation for the A3B5 phases was of interest. As shown in the following, the nonexistence of Zr3Rhs has been established, the structures of Ti3Rh5 and Hf3Rh5 have been worked out, and crystal chemical relationships and stability criteria are reported. EXPERIMENTAL METHODS AND RESULTS Alloy Preparation and Phase Diagram Work. Alloys were prepared from high-purity (99.99+ pct) elements by arc-meltin3,4.Heat-treated alloys were annealed in a vacuum of 3 x X torr for 24 hr at 1300DC. Metal-lographic samples were etched electrolytically in concentrated HCl with 5 v ac for 5 min.3 X-ray diffraction powder patterns were taken on a GE XRD-5 dif-fractometer with Cum radiation at low scanning rates (0.2 deg per min for 28). It was confirmed that Ti3Rhs and Hf3Rh5 have similar diffraction patterns, and that an alloy with the composition Zr3Rhs has a different pattern. Six Zr-Fh alloys with 59 to 69 at. pct Rh were therefore prepared and investigated in the as-cast state by X-ray diffraction and metallography. Alloys at 59 and 61 at. pct Rh were found to be a single phase, with the distorted B2-CsC1 type structure typical for the off-stoichio- metric region of the phase (Zr,-,Rh,)Rh. This phase forms a eutectic with ZrRhs at about 66 at. pct Rh: accordingly, alloys between 61 and 69 pct at. pct Rh consisted of two phases. There is no evidence for the existence of Zr3Rh5. Based on the results in Rafs. 1 and 5, on the present work on Zr-Rh, and on several additional alloys investigated, the portions between the AB and AB3 stoi-chiometry for Ti-Rh, Zr-Rh, and Hf-Rh are as follows: Further, several ternary alloys near Ti3Rhs and Hf,Rhs were prepared in which it was attempted to replace titanium and hafnium partly by zirconium, niobium, tantalum, and germanium. The results will be discussed in a later section. Structure Determination of Ti3Rh5. Since Ti3Rh5 and Hf3Rh5 are isostructural, the following discussion will largely deal with the former. Although the powder pattern of TisRhs is complex, as found previously,1 it could be indexed by comparison with other structures of A3Bs stoichiometry. Ti3Rh5 was found to be isostructural with Ge3Rh5, whose orthorhombic structure had been elucidated by Geller.9 As both the sizes and atomic numbers of germanium and titanium are comparable, the unit cell volume and the peak intensities could be expected to be similar; however, significant differences exist in the atomic positions, as will be shown. All lines in the powder patterns of Ti3Rh5 and Hf3Rhj could be indexed with primitive orthorhombic unit cells with the lattice constants: The fractional errors are 10 The low-angle portion of the indexed powder pattern of Ti3Rh with sin2 8 < 0.30 is listed in Table I. The extinction laws Okl only with k = 2n and hOl only with h - 2n are compatible with the space group Pbo2 and the more symmetrical space group Phnm of Ge3Rh5. Finally, the positional parameters of Ti3Rh5 and HfsRhs were refined under the assumption that titanium and hafnium occupy the germanium positions in Ge3Rh5. Integrated intensities were obtained from the diffraction patterns by planimetry. Intensities of overlapping reflections were separated by an iteration process incorporated into the least-squares positional refinement program according to a method described previously. The intensities of Ge3Rh5 were used in the first separation cycle, while the atomic parameters of Ge3Rh5 were used as starting values in the first refinement cycle. Absorption due to specimen

Jan 1, 1970

By Oscar M. Kucus

In January and February of the current year, at the Tooele plant of the hternational Smelting Co., Tooele, Utah, a modification of the usual method of converting, for the treatment of copper-lead matte from lead blast furnaces, was developed and put into successful operation. In brief, the method consists in blowing molten matte direct from the blast furnaces in basic-lined converters, without the addition of siliceous fluxing ores, to the almost complete elimination of the lead contained, and to the production of copper bullion, the resulting lead fume being recovered by the filtration of the converter gases through woolen fume bags. The process is carried out in conjunction with the converting of rever-beratory copper matte, the heavy iron slag, together with the copper precipitated, being transferred to converters blowing copper matte. The purpose of this transfer is to reduce the copper oxide formed, due to the necessary overblowing of the lead-matte charge, and to utilize, as far as possible, the value of iron from the lead matte, for the fluxing of siliceous dry ores. The final slag from the copper converters is then skimmed off and transferred molten to a reverberatory smelting furnace treating copper ores. This variation from general converting practice was the outgrowth of results obtained during 1913 when it was endeavored to convert copper-lead matte in the usual manner, with the direct addition of siliceous fluxing ores. To make clear the reasons lying back of the process it is necessary to recount at some length the results of operations during that year. In the design of the lead plant it mas planned to treat the copper-lead matte from the furnaces by direct converting without reconcentration and thereby to recover the copper, silver, and gold as quickly as possible. A converter plant of ample capacity, treating copper matte, already being in operation, it was only necessary to install a bag house, a fan, and the necessary flues to complete the equipment. The bag house constructed has a bag-cloth filtering area of 136,000 sq. ft., provided by 960 fume bags, 18 in. in diameter by 30 ft. in length. A No. 20 Sirocco fan of 180,000 cu. ft. capacity delivers the gases from

Jan 1, 1915

By R. D. Longyear

[Some Problems Involved in the Interpretation of Diamond-drill-hole Sampling and Surve ing (paper by J. J. Collins, Mining Tech., Jan. 1946). ............... I Geologic Interpretation of Magnetic Exploration on the Mesabi Range, Minnesota (paper by R. H. B. Jones, Mining Tech., July 1946) ................... 2] DISCUSSION R. D. LONGYEAR.*-Mr. Collins is to be commended very highly for the brief summary he has made of the currently used methods of taking diamond-drill sludge samples and the principles involved in evaluating the results. This paper should stimulate further discussion and research on this vitally important problem. It is particularly imperative that geologists and engineers know when assay results on sludge recovery can be accepted quantitatively and when they must be considered only qualitatively. In most cases where the sludge recovery is less than 95 per cent or more than 125 per cent, it is safest to consider the assays as of qualitative value only. Certain cases, however, are known where a relatively small proportion of the sludge sampling will give a reasonably accurate measure of the value of the total sample. One such case is ore in which the valuable mineral is of approximately the same specific gravity as the waste mineral, such as chalcopyrite in a massive pyrite body. The essential point is to determine the degree of accuracy of sludge sampling in any given drilling project and to weigh the results accordingly. It should be emphasized, however, that sludge sampling can be made reliable in many localities where careless practice produces unreliable results. In many instances, it is desirable to empty the core barrel in the core shack instead of at the drill, so that the engineer can examine the core as it first comes from the core barrel. It should be pointed out, however, that the drill * E. J. Longyear Co., Minneapolis, Minnesota. runner should be permitted to study the core to guide his future drilling. It is hoped that with the return of more normal conditions after the war geologists, engineers, contractors, and manufacturers will be able to carry on more research along the lines of improved core-barrel design and drilling technique with the objective of increasing core recovery so as to eliminate as far as possible the necessity of relying upon sludge samples. H. M. ROBERTS.*-Whoever in the future will have to do with the search for ore bodies and their exploration will have frequent occasion to refer to the clear and comprehensive summary on diamond-drilling methods by John Collins. His review of the experience of the last 40 years in this technique is invaluable. As Dr. L. D. Ricketts wrote in 1932, "The principles on which an art is founded are usually few and necessarily basic in nature, but he who wishes to achieve the power to select his aides and give success to important undertakings that may be intrusted to him in the future must ordinarily undergo years of drudgery in order to gain the experience that will enable him to distinguish such fundamentals through the haze of reinforcing detail that clothes and tends to disguise them."[t] Ricketts went on to say that since the beginning of the century there has been much

Jan 1, 1946

By M. C. Fuerstenau, D. N. Collins, R. B. Bhappu, D. N. Moir

D. N. Moir (Senior Scientific Officer, Warren Spring Laboratory, D.S.I.R. Stevenage) and D. N. Collins (Scientific Officer, Warren Spring Laboratory, D.S.I.R., Stevenage, England) — During work on the petroleum sulphonate flotation of beryl in 1959 at Harwell, and subsequently at Warren Spring Laboratory, effects similar to those mentioned by the authors were noticed. Brief details of some of this work were given to the 6th International Mineral Processing Congress at Cannes.&apos; It is interesting to note that the authors experienced strong activation effects with Fe+++ ions on beryl when using petroleum sulphonate collectors. This phenomenon was of interest in our work when

Jan 1, 1963

By E. L. Anderson, J. R. Long, R. S. Dean, F. S. Wartman

Titanium has been estimated to comprise about 0.65 per cent of the earth&apos;s crust and ranks fourth in abundance among the metallic elements suitable for engineering uses. In spite of this, applications of titanium for structural purposes have not as yet been developed. Its commercial exploitation has been largely confined to the chemical industries and the production of paints and pigments; no doubt because of the difficulties that lie in the way of preparing the pure ductile metal. Published reports, however, indicate that ductile titanium can be prepared and possesses some unique properties. This, together with the occurrence in this country of several important titaniferous deposits, has led the Bureau of Mines to investigate processes for the production of metallic titanium, methods required for its fabrication, and the properties that may be produced in this interesting metal. Methods of Preparing Metallic Titanium Many early investigators claimed to have isolated metallic titanium; but in the light of present knowledge, it seems that they really had produced various mixtures of carbides and nitrides that have a metallic appearance but are brittle, hard, and unworkable. The first metallic titanium pure enough to be malleable when cold was produced by Hunter1 in the early part of the twentieth century. Kroll,~ van Arkel,~ and Fast,4 subsequently confirmed the facts that pure titanium is a. ductile metal and that small amounts of impurities were responsible for previous reports of brittleness. When heated, titanium reacts chemically with various gases, such as hydrogen, oxygen and nitrogen; if the volume of gas thus absorbed is too great, the metal becomes brittle and unworkable. The principal difficulty in making ductile titanium is prevention of such contamination, and the success of a given process may be judged by the completeness with which it solves this difficulty in a practical manner. Of the gases mentioned, hydrogen is the least objectionable, since its absorption by the metal is completely reversible and, although dimensional changes occur and absorption of hydrogen embrittles the metal, the gas may be removed readily by heating in a high vacuum for a short time. On the other hand, the absorption of oxygen or nitrogen results in the formation of permanent solid solutions of the oxide and nitride, which cannot be decomposed by the strongest reducing agentsz with sufticient completeness to restore the inherent ductility of the metal. Because of

Jan 1, 1946

By J. R. Long, E. L. Anderson, R. S. Dean, F. S. Wartman

Titanium has been estimated to comprise about 0.65 per cent of the earth&apos;s crust and ranks fourth in abundance among the metallic elements suitable for engineering uses. In spite of this, applications of titanium for structural purposes have not as yet been developed. Its commercial exploitation has been largely confined to the chemical industries and the production of paints and pigments; no doubt because of the difficulties that lie in the way of preparing the pure ductile metal. Published reports, however, indicate that ductile titanium can be prepared and possesses some unique properties. This, together with the occurrence in this country of several important titaniferous deposits, has led the Bureau of Mines to investigate processes for the production of metallic titanium, methods required for its fabrication, and the properties that may be produced in this interesting metal. Methods of Preparing Metallic Titanium Many early investigators claimed to have isolated metallic titanium; but in the light of present knowledge, it seems that they really had produced various mixtures of carbides and nitrides that have a metallic appearance but are brittle, hard, and unworkable. The first metallic titanium pure enough to be malleable when cold was produced by Hunter1 in the early part of the twentieth century. Kroll,~ van Arkel,~ and Fast,4 subsequently confirmed the facts that pure titanium is a. ductile metal and that small amounts of impurities were responsible for previous reports of brittleness. When heated, titanium reacts chemically with various gases, such as hydrogen, oxygen and nitrogen; if the volume of gas thus absorbed is too great, the metal becomes brittle and unworkable. The principal difficulty in making ductile titanium is prevention of such contamination, and the success of a given process may be judged by the completeness with which it solves this difficulty in a practical manner. Of the gases mentioned, hydrogen is the least objectionable, since its absorption by the metal is completely reversible and, although dimensional changes occur and absorption of hydrogen embrittles the metal, the gas may be removed readily by heating in a high vacuum for a short time. On the other hand, the absorption of oxygen or nitrogen results in the formation of permanent solid solutions of the oxide and nitride, which cannot be decomposed by the strongest reducing agentsz with sufticient completeness to restore the inherent ductility of the metal. Because of

Jan 1, 1946

By F. Pošepný

Part I.—General Facts and Theories. PAGE 1. Systems of Classification Employed Hitherto, . . 199 2. Standpoint and View of the Present Paper, . . . 206 3. The Xenogenites in General, ...207 4. The Subterranean Water-Oirculation, . . . 212 A. The Vadose Underground Circulation, . . . 213 Filling of Open Spaces Formed by Vadose Circulation, . . 217 B. The Deep Underground Circulation, . 220 Ascending Waters Encountered in Mines, , 222 Related Phenomena near the Surface, . 225 Mineral Springs at the Surface,. . 230 Chemical Constitution of Mineral Waters, . 232 Minute Metallic Admixtures in Mineral Waters, . . . 238 Alterations Produced by Mineral Springs, . 240 Structural Features of the Deposits of Mineral Springs, . . 244 5. Origin of Ore-Deposits in the Deep Region, . . . 247 Manner of Filling of Open Spaces in General, . . . 254 Part II.—Examples or Classes of Deposits. 1. Ore-Deposits in Spaces of Discission, .. 264 General Features and Illustrations, a. Ore-Veins in Stratified Rocks, .. 269 Clausthal, 269; Andreasberg, 270. b. Ore-veins in the Neighborhood of Eruptive Masses, 271 The Erzgebirge, 271; Przibram, 272. c. Ore-Veins Wholly Within Large Eruptive Formations, 274 Hungary, 274; Dacian Gold-field. 275; Verespatak, 276; Vulkoj, 276 ; Comstock lode, 278.

Jan 1, 1894

By C. Edward Capes

Fine particles in liquid suspension can be agglomerated by a number of mechanisms. Well-known methods include the addition of electrolyte to reduce the zeta potential and allow mutual adhesion arid the use of polymeric flocculants to bridge between the particles. A more recent technique, "spherical Agglomeration", is the subject of this paper. The process involves the addition of a second liquid which is immiscible with the suspending liquid and preferentially wets the particles to cause particle adhesion by capillary liquid bridges. Progress in the application of spherical agglomeration to a number of distinct technological fields is reviewed in this paper. The areas of interest include the formation of dense, highly spherical agglomerates, the separation of solids from suspension and the fractionation of complex, multi-component solids mixtures, such as ores. Some of the more interesting recent applications in the energy and environmental fields, such as the beneficiation of&apos; coal and tar sands, are highlighted.

Jan 1, 1977

By E. T. Hunter

Surrounded by the 13,000-ft high peaks of the San Juan Mountains in southwestern Colo., the town of Silverton is the site of the extensive development operations initiated 20 months ago by Standard Metals Corp. Appropriately termed the Silverton Project, Standard&apos;s operation has now passed the half-way point in its program to reopen two mines that were once sizeable producers of copper, lead, and zinc ores.

Jan 1, 1961

By Larry D. Patts

Section 317(e) of the Federal Coal Mine Health & Safety Act of 1969 directed the Secretary of the Interior to prepare standards under which all working places in a mine shall be illuminated by permissible lighting while persons are working in such places. Section 317(e) further provides that such working places shall be illuminated within 18 months after such standards are promulgated. In accordance with this section of the Act, there was published in the Federal Register for December 91, 1970, a notice of proposed rulemaking which prescribed the illumination to be provided in the working places of underground coal mines. In light of written comments, suggestions, and objections to this proposed rulemaking, the proposedstandards were withdrawn and reproposed in the Federal Register for Wednesday, October 27,-19h. In light of further comments, suggestions, and objections, a public hearing was held on April 4, 1974, and standards were again reproposed and published in the Federal Register for April 1, 1976. Promulgation of the final lighting standards took place on October 1, 1976, which means that the underground coal mining industry must comply with face illumination requirements by April 1, 1978. As mentioned previously, the first proposed rulemaking for illumination of underground coal mines was published in the Federal Register on October 27. 1971. In early 1972, Consolidation Coal Company (Consol) and the United States Bureau of Mines agreed to a cooperative study of underground face illumination: Consol felt that expertise is this field would become increasingly important. Consol&apos;s initial efforts in illumination were aimed at investigating practical lighting systems for underground face equipment. We were concerned with installing unobtrusive lights which provided sufficient face illumination for safety, but at the same time were readily maintainable, electrically reliable, and physically sheltered from damage. We believe that our initial lighting systems did provide sufficient face lighting for safety, but because only prototype components were available for field testing, the resultant poor system reliability and maintainability necessitated drastic improvement before face lighting could become practical. Final Lighting Standards Deem Early Lighting Installations Out Of Compliance On April 1, 1976, the Federal Register contained the final version of the illumination standards (as they were later promulgated in October). When these illumination regulations and measurement techniques were defined and measuring instruments were available, Consol checked their lighting systems underground and determined that the systems were not in compliance with these final illumination standards. More Lighting Hardware Added In An Attempt To Achieve Compliance. After determining that all of our face lighting systems were not in compliance, we began adding additional lighting hardware in order to meet compliance with published regulations. Unfortunately, to date, we have not been able to meet compliance with practical lighting systems. We have determined from our field installations that the required additional lighting hardware, (to meet compliance) with its increased vulnerability and decreased reliability, renders the lighting systems impractical, if not impossible, to reasonably maintain. Our attempts to provide 0.06 footlamberts have also produced adverse operator reaction to the glare and to illumination systems in general. BCOA Members Ask MESA To Demonstrate Practicability Of Compliance With Regulations Industry concern about meeting the impending lighting regulations was mounting, and in May of 1976 a meeting between MESA and BCOA members was held to discuss lighting compliance problems. At this meeting, BCOA offered to work cooperatively with MESA in testing the practicability of various lighting systems mounted on underground mining equipment. Field tests were to be conducted by United States Steel Corporation, American Electric Power Service Corporation, and Consolidation Coal Company. The purpose of this underground field testing was to develop capability to provide adequate face illumination in a safe, workable manner which would not detract from efficiency of operation. BCOA members involved in this cooperative study were to submit necessary machine drawings, sketches, etc. to MESA in order that MESA could perform a "black-box" study and specify the type and location of luminaires to be installed on the test machines. MESA was confident that they could specify lighting systems that would be in compliance and would be practical so as not to detract from efficiency of operation. Consol was first to install lighting hardware under the BCOA/MESA cooperative agreement. As per MESA specifications, Control Products HgV luminaires were installed on a Joy 2BT-2H boring machine at the Williams Mine of Northern West Virginia Region. As of mid-October, 1976, Consol had approximately eight weeks operating experience with the lighting system on this boring machine underground and had drawn the following conclusions: The lighting system installed at Williams Mine (1) does not meet compliance with lighting standards as originally proposed by MESA, (2) does not provide illumination in a safe workable manner, and (3) will detract from efficiency of the mining operation due to operational delays. Although Consol has rearranged lights on this boring machine in an attempt to reduce operator objections, a practical lighting system which is "in compliance" has not been arrived at as of this writing.

Jan 1, 1979

By J. R. Long, E. L. Anderson, R. S. Dean, F. S. Wartman

TITANIUM has been estimated to comprise about 0.65 per cent of the earth&apos;s crust and ranks fourth in abundance among the metallic elements suitable for engineering uses. In spite of this, applications of titanium for structural purposes have not as yet been developed. Its commercial exploitation has been largely confined to the chemical industries and the production of paints and pigments; no doubt because of the difficulties that lie in the way of preparing the pure ductile metal. Published reports, however, indicate that ductile titanium can be prepared and possesses some unique properties. This, together with the occurrence in this country of several important titaniferous deposits, has led the Bureau of Mines to investigate processes for the production of metallic titanium, &apos;methods required for its fabrication, and the properties that may be produced in this interesting metal. METHODS OF PREPARING METALLIC TITANIUM Many early investigators claimed to have isolated metallic titanium; but in the light of present knowledge, it seems that they really had produced various mixtures of carbides and nitrides that have a metallic appearance but are brittle, hard, and unworkable. The first metallic titanium pure enough to be malleable when cold was produced by Hunter1 in the early part of the twentieth century. Kroll,2 van Arkel,3 and Fast,4 subsequently confirmed the facts that pure titanium is a ductile metal and that small amounts of impurities were responsible for previous reports of brittleness. When heated, titanium reacts chemically with various gases, such as hydrogen, oxygen and nitrogen; if the volume of gas thus absorbed is too great, the metal becomes brittle and unworkable. The principal difficulty in making ductile titanium is prevention of such contamination, and the success of a given process may be judged by the completeness with which it solves this difficulty in a practical manner. Of the gases mentioned, hydrogen is the least objectionable, since its absorption by the metal is completely reversible and, although dimensional changes occur and absorption of hydrogen embrittles the metal, the gas may be removed readily by heating in a high vacuum for a short time. On the other hand, the absorption of oxygen or nitrogen results in the formation of permanent &apos;solid solutions of the oxide and nitride, which cannot be decomposed by the strongest reducing agents2 with sufficient completeness to restore the inherent ductility of the metal. Because of

Jan 1, 1946

By L. Burris, C. H. Stockman, I. G. Dillion

Zone melting is a purification process in which separation of impurities is effected by slowly moving a narrow melted zone through a bar of solid material. Equations are presented which 1—predict the concentration profiles after successive passes of the zone and 2—give the limiting distribution of solute along the bar after an infinite number of passes of the molten zone. These equations take into account the effect of normal freezing in the last zone length. These equations were solved numerically using an electronic computer, and the concentration profiles are presented as a function of the solute distribution coefficient and the ratio of molten zone to total bar length. ZONE MELTING is a purification process in which separation of impurities is effected by slowly moving a narrow melted zone through a bar of solid material. Separation occurs if the solid freezing from a solution at any moment has a composition different from that of the liquid from which it is freezing. Solutes which lower the freezing point will tend to remain in solution and will be moved in the direction of zone travel. Solutes which raise the freezing point will preferentially freeze out, and they will be moved in a direction opposite to that of zone travel. After repeated unidirectional passage of a molten zone through a bar of material, impurities will be concentrated in the ends of the bar. A limiting concentration gradient will be reached in the bar after a large number of passes of the molten zone. Both the magnitude of this limiting concentration gradient and the rate of movement of solute in any pass depend on the zone length and on the equilibrium concentrations of solute in the liquid and solid phases. The basic theory of zone melting was thoroughly covered by Pfann.1 The purpose of this paper is to extend the theory of zone melting by presenting 1—equations which relate the concentration profiles in successive passes of the zone and 2—equations which give the limiting distribution of solute along the bar after an infinite number of passes of the molten zone. These equations take into account the effect of normal freezing* in the last zone length concentration of a given solute in the solid to the concentration of the same solute in the liquid. Analytical methods for determining the concentration profiles after any pass have been developed by Lord2 and Reiss. The method developed by Lord does not take into account normal freezing in the last zone and also becomes very complicated when the number of passes becomes large. The method developed by Reiss enables the direct calculation of the complete concentration profiles (including that in the last zone) after any pass for values of k close to unity (0.9 < k < 1.1). Both methods are useful and provide valuable insight into the zone melting process. The equations given in this article are based on the same assumptions used by Pfann. These are: 1—uniform composition in the liquid, 2—negligible diffusion in the solid, 3—constant distribution coefficient, 4—constant length of the liquid zone (except at the ends), and 5—solubility of the solute in the melt is not exceeded at any point. Equations for Concentrations in Successive Passes For a melted zone of length 1 at the left-hand end of a bar of uniform unit cross-section, the amount of solute in the liquid is J0Cn-1(x) dx [1] where the subscript is the number of the pass. Cn-1(x) represents the concentration (expressed as weight per unit volume) obtained in the previous

Jan 1, 1956

Nationalization of the coal mining industry in Great Britain was one of the first pieces of major legislation enacted by the post-war Labor Government in 1964. It followed a long period of economic depression with high unemployment and bad industrial relations in the coal mining industry during the 1930&apos;s, and shortages of coal during the last war. Upon nationalization, the National Coal Board took over control of the industry in 1947 and so became the biggest single employer of labor in the western world. As well as the coal mines themselves, it assumed responsibility for a great variety of other assets including coke ovens, byproduct plants, land, houses, railways and shipping wharves.

Jan 6, 1964

By M. T. Martinson, I. W. Nicholson, C. J. Chindgren, F. P. Williams, L. C. Bauerle, S. F. Ravitz

THE vanadiferous shales of southeastern Idaho and southwestern Wyoming constitute the largest known reserve of vanadium in the United States.1 These deposits have never been exploited except for the relatively small amounts of vanadium recovered by the Anaconda Copper Mining Co. in the treatment of phosphate rock from southeastern Idaho. The major domestic source of vanadium has been the sandstone ores of southeastern Utah and southwestern Colorado. Early in World War II, it appeared that these ores could not meet the greatly increased demand for vanadium, so the investigation described in this report was undertaken to develop processes for the recovery of vanadium from the Idaho-Wyoming deposits. The utilization of these deposits became unnecessary, however, because of greatly expanded production from the Utah-Colorado sandstone ores and the continued availability of vanadium from other sources, chiefly Peru. The major use of vanadium is as an alloying agent in the manufacture of high-quality steels. Vanadium constructional steels usually contain 0.05 to 0.20 pct vanadium, which refines the grain and increases the strength, elastic limit, and resistance to shock and fatigue. Vanadium tool steels not used in high-speed work contain 0.10 to 0.60 pct whereas high-speed tool steels contain 1.0 to 4.0 pct. Vanadium compounds are used as catalysts (principally for the oxidation of SO2 to sulphuric acid and of naphthalene to phthalic acid) and in the paint, chemical, ceramic, dye, and printing industries. The selection of the particular ore deposit to be exploited would involve consideration of many factors besides the metallurgical results that might be obtained. Chief among these would be the reserves of ore available, the grade of the ore, and the mining costs. As very little was known about any of these factors, it was necessary to investigate methods of treatment of all the ores under consideration, working with samples obtained in the course of the exploration work, even though they were not positively representative of the whole deposit from which they were taken. Because of wartime conditions prevailing when this investigation was started, first consideration was given to processes that could be put into operation most quickly and would involve minimum use of strategic materials, even though these processes might not be the most economical.

Jan 1, 1947

By U. C. Tainton

THE world-wide continuation of low prices for zinc in 1934 has militated against any striking changes in the position of the metal. The price of zinc in London at the end of the year, about £11 5/8 per long ton, or 2.5c per pound at the existing rate of exchange, is more than 25 per cent below the average price for last year. In these circumstances probably the most significant event of the year was the putting into operation of the new electrolytic plant of the Giesches company at Magdeburg, Germany. This plant is designed to have an initial capacity of 20,000 long tons per year, and it is planned to increase this to 40,000 tons annually. This development is significant not only as indicating a continued swing of zinc metallurgy towards electrolytic methods, but also because it will make Germany virtually independent of foreign sources of zinc. This will mean that the zinc tonnage normally exported to Germany from Belgium and Poland will. become available for other markets, and it is feared may lead to lower prices unless the production of Bel-

Jan 1, 1935

By J. Weijdema, D. N. Dietz

In the conventional underground combustion process (dry combustion) much heat is left behind in the swept formation and goes to rva.rte. Econonmy can be improved by heat recuperation through water injection. This is most advantageous if done at the earliest opportunity before much heat is dissiputed to cap and base rock. Water injected simultaneously with the air will flash to superheated steam, which passes through the combustion front together with the nitrogen from the air. A condensation front traveling up to three times as fast as the combustion front drives out the oil. In this type of wet combustion, the water evaporates before it reaches the combustion zone. The evaporation front travels more slowly than the combustion zone. If so much water is injected that the evaporation front overrun the combustion front, combustion in that spot will be quenched and some unburned fuel will be left behind. Air reacts with the oil farther down-stream where steam temperatures occur; at steam temperature, the air reacts rapidly with the oil. Velocity of the combustion front is increased thereby and is governed essentially by the water-injection rate. In the extreme case of high water-injection rate, a short heat wave of constant length is driven through the formation by water injection. Once this wave has been established, no more heat need be generated than that required to make up the heat losses from the short heat wave; a relatively low rate of air injection will suffice. The feasibility of partially quenched combustion has been confirmed in tube experiments. A heat wave at steam temperature is observed. Chemical analyses of flue gas indicate preferential burning of hydrogen while a carbonaceous residue is left in the formation. Introduction A disadvantage of so-called dry in situ combustion is that air-compression costs are rather high. An air consumption of about 400 std cu m/cu m (400 scf/cu ft) of formation swept is an accepted figure. This high consumption is mostly wasted since much heat is left behind in the depleted oil sand. Methods were investigated for recuperating as much as possible of the heat left behind. This paper deals only with basic principles and is confined mainly to one-dimen- sional flow without lateral heat losses; experiments were conducted in relatively narrow, well insulated tubes. If some water is injected with the air, it will turn to superheated steam in an evaporation front, which should travel behind the combustion front. The steam having passed the combustion front causes a steam drive by a condensation front that can travel faster than the combustion front. The latter needs to travel only part of the distance covered by the oil-displacing condensation front, and thus consumes less air. The water-air ratio would seem limited to that at which cold water overruns the combustion. This limitation was deliberately exceeded considerably in theory and experiments. It was found that combustion is then indeed quenched, but only locally. Farther downstream, the oxygen finds residual oil at steam temperature, which is suficiently high to ensure rapid oxidation. Thus, the combustion front uses only part of the available fuel because it is chased through the formation faster than its normal velocity. No heat is left behind. This new process is called "partially quenched combustion". At the upper limit of the water-air ratio, a small heat slug is moved through the formation by the flow of water and steam. Only a small flow of air is needed since it has only to generate sufficient heat to make up for the lateral heat losses of the short heat slug. Theory Although many factors complicate underground combustion, the processes will be presented in their simplest form. For this reason, one-dimensional flow without lateral heat losses is assumed. Heat conduction in the direction of flow also is disregarded. Under these conditions, dry combustion causes very high temperatures. The heat-carrying capacity of the gas stream is small. Heat generated by oxidation of a residual oil saturation is retained in the sand. The available fuel determines the air requirement and the temperature obtained. Accepting the often-mentioned air consumption of 400 std cu m/cu m (400 scf/cu ft) formation, we calculate a temperature of the swept sand of 1,200C (2,192F) (Fig, I). If water is injected at a modest rate with the air, it will flash to superheated steam upon contact with the heated sand. One cu m (35.31 cu ft) of hot formation will evaporate about 0.5 cu m (17.66 cu ft) of water, and thereafter will accommodate (at an estimated 0.80 saturation and an assumed 0.40 porosity) another 0.3 cu m (10.59 cu ft) of water in cold condition. As long as less than 0.5 + 0.3 = 0.8 cu m (28.25 cu ft) of water is injected for every 400 std cu m (14,125 scf) of air (water-

Jan 1, 1969

By R. A. Wood, R. I. Jaffee, H. R. Ogden, D. N. Williams

Dispersion-containing titanium-copper alloys were prepared having mean free paths varying from 1.0 to 9.7 P. Tensile studies at room temperature and at 1000°F showed that little or no strengthening occurred when the mean free path exceeded 3 p. However, at lower values of mean free path appreczable strengthening was observed. A considerable amount of strengthening also resulted from copper in solid solution. DURING the past several years, an increasing amount of study has been devoted to dispersion hardening, an alloying process in which increased strength is obtained through the addition of a ran-

Jan 1, 1961

By Colin MacDonald

The choices of an uranium mill flowsheet are pri- marily determined by economic feasibility with plant location and regulatory bodies playing a lesser but still important role in this determination. The host ore bodies will determine the leach pro- cess to be used for basic uranium extraction. Im- mediately following this decision, the method of leaching has to be determined. These can be: - Atmospheric leaching - Pressure leaching - In-situ leaching - Heap leaching The three previously stated criteria lay important parts in this decision. In the case of atmospheric or pressure leach and once the soluabilized uranium has been liberated from the host gang material, liquid solids separation becomes the major criteria. Three process flowsheets are available; they being: -Countercurrent decantation - Countercurrent or co-current filtration - Resin in pulp Following liquid solids separation, concentration and precipitation become the next variable choice. They being: -Solvent extraction - Fixed bed ion exchange - Fluid bed ion exchange Lastly, washing and drying of the precipitated product to remove impurities can be carried out by either filtration or centrifugation. With the exclusion of milling circuits, grinding circuits, flotation circuits, and calcining processes, we have 240 variations of the flowsheet between leaching and a dry washed precipitate. Of this total, filtration in one form or another and in single or multiple applied forms has application in 144 streams. This paper intends to discuss four (4) facets of the total flowsheet in which filtration is applied, following grinding and prior to calcining. They are: - Leached pulp liquid solid separation - Tailings dewatering - Pregnant solution clarification - Yellow cake washing and dewatering

Jan 1, 1980

By E. H. GRAFF

PREPARATION of mechanically loaded coal in mines where seams contain considerable impurities is a subject that requires careful consideration before machines are installed, unless provision is made at the tipple for its preparation. Conditions vary a great deal in the different seams, so much so that a mechanical loader may be unsuccessful in one seam and yet the same machine may make good in another where conditions are different. The effect of impurities in the coal seam on mechanical loading will also vary according to the thickness of the seam. In thin seams impurities will be more difficult to remove than from thick seams, as will appear later. For the past several years the New River Co. has done considerable experimenting with loading equipment and during this process has changed from one machine to another.

Jan 1, 1926

By S. G. Cupschalk, F. A. Dahlman, J. J. Wert

Studies have been undertaken to determine the indicidual effects of particle size, degree of long-range ovder, antiphase domain size, and root mean square stran on the microhardness and yield strength of ordered alloys. Dnta have been analyzed for Cu3Pt initzally ordered to a value of 0.82 and after deformations of 1 and 6 pct. It was observed that deformation fleatly reduced the degree of long-range order. Furtherrnore, wztkin this range of relatively small deforntntlons, the average particle size changed very little while the antiphase domain size was greatly reduced. Smultaneosly, the mcrohardness changed by a factor of two durzng the deforrtation process. PREVIOUS studies have reported some of the effects of cold work on the broadening of X-ray diffraction peaks. These investigations were performed on powder and wire samples representing both ordered and disordered states; i.e., the specimens were initially studied in a severly cold-worked condition. By comparing the difference in line shape between the annealed and cold-worked peaks, fundamental information was obtained concerning particle size, strain distribution in different crystallographic directions, degree of long-range order, and change in antiphase domain size. Considerable theoretical work has been done concerning the analysis of diffraction data obtained from cold-worked metals. Stokes&apos; expressed the change in diffraction profiles in terms of Fourier coefficients. Much of the work in this area has been summarized by warren2 in an extensive review article concerning the analysis of plastic deformation by X-ray diffraction. Cohen and Bever3 applied these techniques in studying the effects of cold work on alloy systems exhibiting long-range order. They utilized the Fourier coefficients of fundamental peaks in conjunction with those of the superlattice peaks to determine the change in antiphase domain size. Little work of this nature has been reported for ordered systems that have undergone small degrees of plastic deformation. The purpose of this investiga-tion was to determine the effects of small deformations in such a material with respect to particle size, strain distribution in various crystallographic directions, antiphase domain size, degree of long-range order, and hardness. EXPERIMENTAL PROCEDURE CusPt was used for the initial investigation since the order-disorder transformation takes place with- out a change in crystal structure. The transformation is readily detectable via X-ray diffraction techniques due to the large difference in the scattering factors of copper and platinum. Additionally, the alloy is relatively low melting (approximately 1300°C) and is easily deformable in both the ordered and disordered states. 1) Specimen Preparation and Cold Working. A 100-g, 12-in. diam., cylindrical specimen of Cu3Pt was prepared by melting and casting 99.99 pct pure Cu and Pt i.n vacuo. Prior to any mechanical working, the material was homogenized in a vacuum for 60 hr at 100O0C, and surface defects were removed by machining to a depth of approximately 116 of an in. The material was then cold-rolled, with an intermediate anneal, into a strip approximately 12 in. wide by 14 in. thick. Straightening and flattening removed another 0.025 in. from the thickness. After a recrystallization treatment at 750°C for 30 min, the specimen was slow-cooled from 55OoC, at the rate of 6°C per hr, down to 150°C to induce superlattice formation. This treatment yielded an ASTM grain size of 7 and a degree of long-range order equal to 0.83 0.06. After obtaining X-ray and Knoop hardness data, the sample was cold-rolled approximately 0.75 pct in one pass through a hand-operated jewelers&apos; mill. X-ray and hardness data were again obtained and the specimen was reduced an additional 5.41 pct in a single pass through the mill. 2) X-Ray Measurements. The specimen was examined in the ordered condition and after the two degrees of cold working previously mentioned using a General Electric XRD-5 unit equipped with a spectrometer and scintillation counter. Using Mo-Ka radiation with a zirconium filter, six orders of the 100 reflection were obtained. It was anticipated that point counting would be necessary for an accurate determination of the low-intensity peaks and tails: however, it was demonstrated that, by using a scanning speed of 0.2 deg per min and the appropriate time constant, the recorded data were sufficiently accurate. Thus, for ease of experimental procedure, all peaks were recorded on chart paper. Specimen position in the holder was considered to be insignificant after making a series of measurements of the same peak area in different positions with respect to the beam. Since peak overlapping did occur at high values of 20, it was necessary to separate the peaks graphically prior to analyzing the data in order to minimize this source of error. The peak tails were also carefully drawn to obtain the best possible data. Fourier coefficients of the line profiles were calculated on an IBM 7072 computer, and graphical meth-ods2j3 were employed in analyzing the results. For this type of calculation, in which the line profile is represented by intensities taken at set intervals, the intervals selected must be sufficiently small to give an accurate representation of the line profile. It was decided that for 20 = 0.02 deg the line profiles were

Jan 1, 1967