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By Arnt Solbu, Jomar Thonstad

The reaction between CO, and aluminum in cryolite-alumina melts in contact with aluminum has been studied by passing CO2 over the melt. In unstirred melts a homogeneous reaction between dissolved metal and dissolved CO2 was observed. In stirred melts in which convection was induced by bubbling argon through the melt, the dissolved metal apparently reacted mainly with gaseous CO2. The rate of formation of CO increased slightly with increasing depth of the melt, and it did not depend on whether CO2 was passed over or bubbled through the melt. The rate of formation of CO increased with increasing area of the metal/melt interface and with the application of anodic current to the metal. It is concluded that the dissolution of metal into the melt is the rate-determining reaction. THE current efficiency in aluminum electrolysis is determined by the rate of the recombination reaction between the anode gas and the metal: 2A1 + 3CO2—A12O3 + 3CO [1] as originally stated by Pearson and waddington.1 The occurrence of this reaction in cryolite-alumina melts in contact with aluminum was first verified experimentally by Schadinger.2 Thonstad3 has shown that the reaction may proceed further to give free carbon: 2A1 + 3CO— A12O3 + 3C [2] Normally only a few percent of the CO formed undergoes such reduction. The mechanism of these reactions has not yet been clarified. Aluminum, as well as CO,, is soluble in the melt. The solubility of aluminum in cryolite-alumina melts at around 1000°C corresponds to 75 x 10- 6 mole A1 per cu cm,4 while that of CO2 is only 3 x 10-6 mole CO, per cu cm.5 Taking into account the stoichiometry of Reaction [I], the ratio between dissolved aluminum and dissolved CO2 available for the reaction in a saturated melt is about 40. Therefore, as will be shown in the following, the reaction probably mainly occurs between gaseous COa and dissolved aluminum. The dissolved aluminum presumably consists of subvalent ions of aluminum and sodium.4'6 Since the interpretation of the present results is not dependent upon the nature of this solution, the dissolved metal will be designated solely as Al+ in the following. The reaction can then be divided into four steps: A) dissolution of metal, e.g., 2A1 + Al3 — 3A1+ [3] B) diffusion of dissolved metal through a boundary layer; C) transport of dissolved metal through the bulk of the melt; D) Reaction [1]. If dissolved CO, takes part in the reaction, three additional steps embodying the dissolution and transport of CO2 must be added. schadinger2 observed, when bubbling CO2 through the melt, that the rate of formation of CO (in the following designated rfco) did not depend on the distance from the metal surface. The results also indicate that the rate of bubbling did not affect the rfco. When passing CO, over the melt, Revazyan7 found that the loss of metal did not depend on the depth of the melt above the metal or on the flow rate of CO2, and concluded that Step A is rate-determining. In an unstirred melt, however, Gjerstad and welch8 found that the rfCo decreased with increasing depth of the melt, indicating that step C was rate-determining. It thus appears that the rate control of the process depends on the experimental conditions, particularly on the convection. In the present measurements the reaction has been studied in unstirred as well as in stirred melts. EXPERIMENTAL AND RESULTS The experiments were carried out at 1000°C in a Kanthal furnace with a 10-cm uniform temperature zone (±0.l°C). The melts were made up of "super purity" aluminum (99.998 pct), hand-picked natural cryolite, and reagent-grade alumina. In experiments where alumina crucibles were used, the alumina content in the melt was close to saturation (13.5 wt pct9); otherwise it was 4 wt pct. Pure Co2 (99.85 pct) was passed over the melt, and the exit gas was analyzed for CO2 and CO by the conventional absorption method.3 From the weighed amount of CO (as CO2) the rfco was calculated as the number of moles of CO formed per min per sq cm of the surface area of the melt. The amount of carbon formed by Reaction [2] was not determined. As already indicated the rfco is much higher than the rfC, by Reaction [2]. Since the rfC probably is proportional to the rfco, the measured rfco should then the proportional to, but slightly lower than, the total rate of Reactions [I] and 121. In general the scatter of results obtained in duplicate measurements was ±5 to 10 pct, while within a given run a precision of ±3 to 5 pct was obtained. The various crucible assemblies that were used will be described below. Measurements in Unstirred Melts. When carrying out aluminum electrolysis in small alumina crucibles. Tuset10 observed that after solidification the lower part of the electrolyte was gray and contained free metal, while the upper part near the anode was white and contained no metal. One may test for the presence of free metal by treating with dilute hydrochlorid acid.

Jan 1, 1969

By H. T. Shore, J. M. Schultz

A number of experimental rnethods—X-ray powder diffractometry, Laue photography, X-ray small-angle scattering, and transmission electron microscopy and dijfraction—have been utilized to examine the morphology associated with precipitation from the terminal, g, solid solution of a Zn-1 pct Cu alloy. A significant age hardening was observed in a 1 pct Cu alloy. X-ray and electron diffraction results showed that the structural inhomogeneities associated with the hardening were isotructural with the matrix. The average size and shape of the inhomogeneities were deduced from the electron microscopy and X-ray small-angle scattering. The preprecipitates are hexagonal platelets some 300? in diam. and some twelve unit cells thick. The orientation of the platelets was deduced from Laue photographs and electron diffraction. The platelet plane is (0001). When a large amount of pre-precipitation is present in a localized volume the new lattice is often disoriented by a rotation about (0001) of of the matrix. WhILE dilute Zn-Cu alloys have been commercially important for some 50 years, relatively very little is known metallographically about this material. The "Zilloys", zinc with about 1 wt pct Cu and sometimes a small addition of magnesium, are used to produce rolled zinc which is harder and stronger than that produced by other rollable zinc alloys.' According to the phase diagrams of the zinc-rich side of the Cu-Zn system, such dilute Zn-Cu alloys should age-harden;2-5 the solubility of copper in zinc, g-phase, at 424°C is 2.68 pct, while at 0°C it is only to 0.3 pct. However, the published literature on the aging of this system appears to be limited to a documentation of the contraction of 1, 2, and 3 pct Cu alloys aging at 95°c,6 and an attempt to measure changes in lattice parameters during aging.' In the latter work, no lattice parameter changes were detected, although a broadening of the highest-angle lines was detected and considerable diffuse scattering was observed. Micro-structural investigations have been limited to the latest stage of aging, wherein Widmanstatten precipitates are formed.3,47 These alloys are of interest for still another reason. The two most zinc-rich phases in the Cu-Zn system, 77 and E, are both hcp. Moreover, the change in a, between 17 and t for a 1 wt pct Cu alloy is onlv 3.64 -,~ct: the change in Co is 12.0 ict. It would be anticipated that precipitation in such a material might occur through metastable phases or G.P. zones with epitaxy along mutual 0001 planes. The goals of the present work are aimed at partially filling the void of knowledge concerning the early stages of precipitation from the g phase. In particular, we have attempted to document the magnitude of the age hardening of this system and to determine the size, shape, and orientation within the matrix of the elements of precipitation in an early stage of condensation. EXPERIMENTAL A) Specimen Preparation. Specimens were prepared In two somewhat different ways, one method being used for X-ray Laue and diffractometer measurements, optical microscopy, and Rockwell hardness measurements and the other used for electron microscopy and X-ray small-angle scattering. In the first case zinc and copper in the proper proportions to yield a 1 wt pct Cu alloy were melted together in a closed graphite crucible. Castings so made were free of apparent segregation or oxidation. The castings were then solution-annealed at 400°C for several days and then quenched in water to room temperature. Filings of portions of the specimens were made for use as X-ray powder diffractometry specimens. The electron microscope material was made as follows. Castings were made under vacuum with copper powder placed inside a hollow zinc cylinder to insure good contact of the materials. These 1 wt pct Cu pieces were then rolled to 0.1 mm with an intermediate anneal in vacuo. The rolled sheets so formed were then annealed for about 6 hr at 225°C. Finally the specimens were electropolished slowly until thin enough for transmission electron microscopy. The polishing is discussed in greater detail in the Results section. B) Measurements. X-ray measurements of three types were performed. A G.E. XRD-5 diffractometer was used to examine powders of the alloy for identification of second-phase material. A Kratky small-angle camera, also operating from a G.E. tube, was used to investigate the sizes of small precipitate particles. In both cases, nickel-filtered copper radiation was utilized. Finally, individual grains of the large-grained castings were examined in the back-reflection Laue geometry. Electron microscope studies were carried out with a J.E.O.L. Model 6A instrument. RESULTS A) Hardness Measurements. Hardness measurements performed at room temperature on the large-grained polycrystalline specimens showed a hardening which was essentially complete in 3 hr. Fig. 1 shows a typical plot of hardness vs aging time. The relative magnitude of the ultimate hardening varied from run to run between 150 and 200 pct of the value for the material immediately after quenching from the solution anneal. Most probably the variations reflect small changes in the time taken to remove the specimen from the vacuum furnace after the solution anneal.

Jan 1, 1969

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Jan 1, 1925

By A. Totani, S. Nakajima, H. Okazaki

The phase diagram for the SnTe-SnSe system has been studied in the temperature range from 300° to 900°C by differential thermal and quenching techniques. The X-ray measurements were made on quenched specimens. High-temperature diffraction was also made to study the phase transition in SnSe. The system is proved to be of a eutectic type in which no intermetallic compound exists. The eutectic point is at the composition SnTeo.55 Seo.45. the eutectic temperature being 755°C. Solid solubility limits are SnTeo.6Seo.r and SnT eo. 3s Seo.6s at the eutectic temperature, and change almost linearly to SnTeo.aaSeo.lz and SnTeo.18 Seo.az as temperature decreases to 300°C. It was shown that the SnSe phase has a phase transition of the second order at about 540°C and that the transition temperature decreases with increase of the SnTe content. THERMOELECTRIC properties of tin telluride (SnTe) and tin selenide (SnSe) have been studied extensively in recent years. The variation of physical properties with composition could be of interest if these compounds form an appreciable crystalline solution. The purpose of present investigation is to confirm the formation of crystalline solution or intermetallic compound, if any, and to establish the phase diagram for this system. The crystal structure of SnTe is NaCl type with a cubic unit cell1 (a = 6.313A). The crystal of SnSe having an orthorh2mbic unit cellz (a = 11.496, b = 4.1510, and c = 4.4437A) is isomorphous with tin sulfide (SnS) which has a distorted sodium chloride structure. It has been known that SnSe has a phase at at 540°C; the transition has been assumed to be of the second order. As far as we know, only two studies on the SnTe-SnSe pseudobinary system have been reported. The conclusion obtained in these papers is that, in the composition regions near SnTe and SnSe, the system forms a crystalline solution of the SnTe structure and the SnSe structure, respectively, and that, in the intermediate region, both phases coexist. However, neither the variation of the solid solubility vs the temperature nor the liquidus and solidus were investigated. Hence present writers have attempted to determine the phase diagram of the system by differential thermal analysis (D.T.A.) and X-ray diffraction. EXPERIMENTAL Sample Preparation. Starting materials, SnTe and SnSe, were prepared by the direct fusion of commercially available high-purity (99.999 pct) elements. Stoichiometric amounts of each couple Sn-Te or Sn-Se were weighed into a clear fused silica ampule. After evacuation to a pressure below 10-3 mm Hg, the am- pule was sealed, and annealed at 900°C for 5 hr. The melt was quenched in water. X-ray analysis confirmed the formation of a single phase of SnTe or SnSe. The other samples, SnTel-,Sex were synthesized from these SnTe and SnSe by mixing them in the required ratio, followed by annealing at 900°C and quenching. These samples were used directly for D.T.A. For X-ray measurements, samples were annealed at 700°, 600°, or 500°C for 100 hr or at 300°C for 150 hr, and then quenched in water. It was found that the lattice constants of the SnTe phase annealed for 150 hr at temperatures above 500°C did not differ from those annealed for 100 hr at the same temperatures. However the X-ray phase analysis showed that at 300°C the annealing for 150 hr was necessary to attain a true equilibrium state. D.T.A. The solid-liquid equilibrium temperature was determined from D.T.A. measurements. The sample was sealed in an evacuated silica tube and molybdenum powders sealed in an another tube were used as a reference material. The sample and the reference tube were placed in a nickel block and were heated from room temperature to 900°C at a rate of 3°C per min and then cooled down at the same rate to 600°C. Thermocouples for these measurements were Pt-Pt. Rh (10 pct) and the error of temperature measurements was within + l0C. D.T.A. curves were obtained on a two-pen recorder and an automatic controller (PID type) was used for the program of heating and cooling. When temperature reaches the solidus from the low-temperature side, there appears an endothermic peak. The solidus temperature was determined by extrapolation of the straight portion of the starting flank of this peak to the base line. In a similar way, the liquidus temperature was determined from an exothermic peak on D.T.A. cooling curve. In the case of supercooling, if any, its degree can be estimated from the magnitude of the abrupt temperature rise. X-Ray . X-ray powder patterns were taken by a diffractometer using CuK, radiation. Since the SnSe crystal is cleaved easily, the powders become flaky when SnSe-rich samples are ground in an agate

Jan 1, 1969

The curve of Fig. 3 for pyrite requires modification. There 11% a range of pH values from 6.2 to 7.8 for which no cyanide is required to prevent contact. From 7.8 to 11.3 a small amount of cyanide is required, with a sharp maximum of 20 mg. per liter at pH=9.6. The mistake arose from considering too few solution compositions (17 were considered) in constructing the curve. Subsequent work with other collectors indicates that the corrected curve is typical for such systems; it illustrates the further development of the dip in the pyrite curve of Fig. 5.

Jan 1, 1938

By Charles E. Lundin

Pressure-temperature-composition data were obtainedfor the Er-H system. Measurements werecar-ried out in the temperature range of 473° to 1223°K, the composition range of erbium to ErH,, and the pressure range of 10-5 to 760 Torr. Solubility relationships were established from these data throughout the system. Three solid-solution phases were delineated: metal solid solution, dihydride phase, and trihydride phase. The trihydride Phase decomposes at about 656°K and 1 atm pressure. The dihydride phase is stable to about 1023°K, but becomes more deficient in hydrogen above this temperature. The equilibrium decomposition pressure-temperature relationships in the two-phase regions, erbium solid solution plus dihydride and dihydride plus trihydride, were deter- The differential heats of reaction in these two regions are AH = - 52.6 * 0.3 and - 19.8 i 0.2 kcal per mole of Hz, respectively. The differential entropies of reaction are AS = - 35.2 * 0.3 and - 30.1 * 0.4 cal per mole HZ.deg, respectively. Relative partial molal and integral thermodynamic quuntities were calculated in the system to the dihydride phase. RARE earth metal-hydrogen systems have been the subject of general survey,1"4 and all have been found to form hydride phases. The heavy rare earths, of which erbium is a member, form dihydride and trihydride phases with different crystal structures, whereas the light rare earths form only a single-phase dihydride which expands without structure change, as hydrogen is added, to the trihydride composition. These materials are of interest primarily because of their theoretical properties, such as bonding, defect structure, and thermodynamic and electronic characteristics. Erbium has been studied in several previous investigations.5, 6 It was deemed desirable to more thoroughly and accurately define the system, both for the phase equilibria and the thermodynamic properties. I) EXPERIMENTAL PROCEDURE A Sieverts&apos; apparatus was employed to conduct the experimental measurements. Briefly, it consisted of a source of pure hydrogen, a precision gas-measuring buret, a heated reaction chamber, a mercury manometer, and two McLeod gages (a CVC, GM 100A and CVC, GM 110). Pure hydrogen was obtained by passing hydrogen through a heated Pd-Ag thimble. The hydrogen was analyzed and found to have only a trace of oxygen and nitrogen. A 100-ml precision gas buret graduated to 0.1-ml divisions was used to measure and admit hydrogen to the reaction chamber. The reaction unit consisted of a quartz tube surrounded by a nichrome-wound furnace. The furnace temperature was controlled by a recorder-controller to ±1°K. An independent measurement of the sample temperature in the quartz tube was made by means of a chromel-alumel thermocouple situated outside, but adjacent to, the quartz tube near the specimen. Pressure in the manometer range was measured to ±0.5 Torr and in the McLeod range (10-4 to 10 Torr) to ±3 pct. The hydrogen compositions in erbium were calculated in terms of hydrogen-to-erbium atomic ratio. These compositions were estimated to be ±0.01 H/Er. The erbium metal was obtained from the Lunex Co. in the form of sponge. The metal was nuclear grade with a purity of 99.9 pct +. The oxygen content was reported to be 340 ppm and the nitrogen not detectable. Metallographically the structure was almost free of second phase (<1 vol pct). A quantity of sponge was arc-melted for use as charge material. The solid material was compared with the sponge in the pressure-temperature-composition relationships. They were found to be identical. Therefore, sponge material was used henceforth, so that equilibrium could be attained more rapidly. The specimen size was about 0.2 grain for each loading of the reaction chamber. The procedure employed to obtain the pressure-temperature-composition data was to develop experimentally a family of isothermal curves of composition vs pressure. First, a specimen of erbium was wrapped in a tungsten foil capsule to prevent contact with the quartz tube. After loading the specimen, the system was evacuated to less than l0-6 Torr, flushed several times with high-purity hydrogen, and evacuated again ready for the start of the experiment. The furnace was then brought to the desired temperature. A measured amount of hydrogen was admitted into the chamber. Equilibrium was allowed to be attained, the pressure read, and the process then repeated many times until 1 atm of gas pressure was finally reached. Other isotherms were then developed in the same manner. The partial pressure plateaus were determined by another manner. In the solid solution-dihydride region a composition of approximately 1.0 H/Er was selected on the plateau. The temperature was varied throughout the range of interest. At each temperature level, equilibrium was achieved, the pressure read, and the next temperature attained. The temperature was cycled both up and down. In the dihydride-trihy-dride region, the plateaus were determined in the 473" to 651°K range only by heating to the desired temperature and not by both heating and cooling. The data were much more reproducible in this manner. Equilibrium required long periods of time. Specimens were initially hydrided to 2.8 H/Er, so that at the higher

Jan 1, 1969

By Rudolf Gahl

THE history of flotation in America is very short, at least as far as the large-scale application of the process is concerned. It is remarkable how many important developments have taken place inn the last few years and are already being extensively utilized. What was new a year ago, seems almost commonplace now. For this reason it is with hesitation that I follow the suggestion: of Dr. Ricketts, President of the Institute, to describe the experiences of the Inspiration Consolidated Copper Co. with the flotation process. TESTS CONDUCTED IN SMALL TEST-MILL When the Inspiration company first decided to build a concentrating plant, nothing was known about flotation, and the process was to be gravity concentration pure and simple. Demonstration Tests Conducted by Minerals Separation Co. While plans were being prepared by H. Kenyon Burch (who had been intrusted with the design and construction of the concentrator) the Minerals Separation Co., a concern at that time little known in America, asked and obtained permission to demonstrate the value of its flotation process for Inspiration ore. As. a consequence, a small 50-ton flotation machine of standard design was added to the company&apos;s test plant and started to operate in the beginning of 1913. This marks the beginning of flotation at Inspiration. The results obtained with this machine, which was operated by members of the Minerals Separation staff, so far surpassed what this company anticipated that it was decided to continue flotation tests for this purpose, and two of the flotation experts of the Minerals Separation Co., I. L. Greninger and G. A. Chapman, were retained. L. R. Wallace, now superintendent of the Miami works of the International Smelting Co., was at that time metallurgist of the Inspiration company and in that capacity took an active part&apos; in these tests. Great credit is due to him for his quick recognition of the possibilities of flotation.

Jan 9, 1916

By John B. Baker, Bernard B. Betty, H. F. Moore

For several years there has been in progress in the Materials Testing Laboratory of the University of Illinois an investigation of creep and fracture of lead and lead alloys. In the course of this investigation it has been shown that the phenomenon of creep occurs in part at the grain boundaries of lead and lead alloys. To study the occurrence of creep and the development of fracture within crystalline grains, two series of tests of single crystals of lead have been carried out. The first of these, a preliminary series, by Mr. Betty, has been described.l,2 The second, pursued by Mr. Baker for his doctoral dissertation, was carried out under the direction of Professor Moore, with the assistance of Prof. G. L. Clark in the X-ray work, and the cooperation and advice of Mr. Betty. This paper is based on the test data obtained in this second series. Single crystals of a very pure commercial lead have been prepared, some of them tested to measure creep, others tested to fracture under long-continued steady load, and still others tested under cycles of repeated tension. An interpretation of the test data of these single-crystal tests is offered, which is a combination of parts of several well-known theories. Specimens The single-crystal specimens were made from a piece of very pure commercial lead sheathing. A spectroscopic analysis of one of the single crystals showed the presence of 0.005 per cent Bi, 0.0001 per cent Cu and 0.0003 per cent Ag. Preparation.—The Bridgman method of casting single-crystal specimens was used.3 The specimens were cast to the shape and size shown in Fig. 1 (dimensions in Fig. 4c) in a duralumin mold. Molten lead does not stick to duralumin. Fig. 1 shows the mold and the blast flames for heating. After the mold had been heated to the temperature of molten

Jan 1, 1938

By John B. Baker, Bernard B. Betty, H. F. Moore

For several years there has been in progress in the Materials Testing Laboratory of the University of Illinois an investigation of creep and fracture of lead and lead alloys. In the course of this investigation it has been shown that the phenomenon of creep occurs in part at the grain boundaries of lead and lead alloys. To study the occurrence of creep and the development of fracture within crystalline grains, two series of tests of single crystals of lead have been carried out. The first of these, a preliminary series, by Mr. Betty, has been described.l,2 The second, pursued by Mr. Baker for his doctoral dissertation, was carried out under the direction of Professor Moore, with the assistance of Prof. G. L. Clark in the X-ray work, and the cooperation and advice of Mr. Betty. This paper is based on the test data obtained in this second series. Single crystals of a very pure commercial lead have been prepared, some of them tested to measure creep, others tested to fracture under long-continued steady load, and still others tested under cycles of repeated tension. An interpretation of the test data of these single-crystal tests is offered, which is a combination of parts of several well-known theories. Specimens The single-crystal specimens were made from a piece of very pure commercial lead sheathing. A spectroscopic analysis of one of the single crystals showed the presence of 0.005 per cent Bi, 0.0001 per cent Cu and 0.0003 per cent Ag. Preparation.—The Bridgman method of casting single-crystal specimens was used.3 The specimens were cast to the shape and size shown in Fig. 1 (dimensions in Fig. 4c) in a duralumin mold. Molten lead does not stick to duralumin. Fig. 1 shows the mold and the blast flames for heating. After the mold had been heated to the temperature of molten

Jan 1, 1938

By W. G. Matteson

The Oklahoma legislature recently passed a bill providing for "the creation of an oil and gas department under the jurisdiction of the Corporation Commission, authorizing the Corporation Commission to appoint a chief oil and gas conservation agent, and conferring exclusive jurisdiction on the Corporation Commission in reference to the conservation of oil and gas, and the inspection of gasoline and oil, the product of crude petroleum, and repealing all acts or parts of acts in conflict therewith and declaring an emergency." Some of the functions of the new bureau include the receiving and filing of all well logs, and the direction and supervision of plugging all abandoned oil and gas wells, under rules prescribed by the Corporation Commission. The two leading petroleum-producing States of the country, Oklahoma and California, have now established oil and gas bureaus with a staff of inspectors to see that the important rules relating to the conservation of oil and gas are thoroughly enforced. The economic significance and the value of well logs in the conservation work has been recognized, and the necessary legal action taken to insure and procure them. William B. Heroy, of the Government Land Classification Board, in a personal communication to the writer, says that the drilling of wells is also regulated by public authority in the Roswell artesian basin in southeastern New Mexico, where a permit must be obtained for the drilling of any well and a certified log of the well recorded with a county official. The method is said to give fairly satisfactory results. In a recent article1 a National instead of a State Bureau was suggested for collecting and filing well logs. In discussing the paper, L. L. Hutchison characterized such a plan as impractical because the average driller or contractor will often juggle or guess at the log and will not keep the record sufficiently close or accurate, making it necessary to maintain a special man at each well for the sole purpose of obtaining

Jan 1, 1918

By C. R. Barker, D. A. Summers, H. D. Keith

Introduction Historically, the presence of methane has been a problem, mainly in and around the working areas of active coal mines, and only in these areas has drainage been considered. Drainage, where practical, has been achieved through the drilling of holes forward into the coal and the surrounding strata from the working area. These holes generaly have been short in length, although where methane drainage operations around a longwall face have been undertaken, the holes have had to be longer in order to adequately drain from the center of the face into the access gate roads. In recent years, attempts have been made to degasify the coal seams in advance of mining, without disruption of the mining cycle. This is done by drilling much longer horizontal holes through the coal in advance of the working area. Under the aegis of the federal government, methods have also been developed for draining coal seams of their methane content in advance of mining, but from shafts sunk from the surface, without using the active area of the mine as the location for the drill holes. Development of methane drainage has recently been encouraged by the potential use of the drained methane as a commercial energy source, with a need, therefore, to adequately organize a collection system, separate from mining the seam for coal. This has already been successfully accomplished, for example, in the Federal No. 2 mine of Eastern Associated Coal Corp. starting in 1975 (Johns). However, whether the system gains access to the coal through horizontal drilling from a pre- existing mine or via access through a separate shaft from the surface, long horizontal holes are required to adequately tap the methane reserve. It is to this regard-the actual drilling of the horizontal holes-that this paper is directed. It will examine potential benefits that may accrue, both in conventional horizontal hole drilling from a mine site underground, and also in drilling from the surface if a high pressure water jet drill is used to drill the degasification holes. Long Hole Drilling from an Underground Site Personnel from the Bureau of Mines have recently examined methods for conventional drilling of long horizontal holes to gain access for methane drainage. They have shown that it is possible (Cervik, Fields, and Aul) to drill out some 610 m using a conventional drilling system. Three types of bit were used in the program and by alternating between a drag bit, tricone bit, and plug bit, advance rates of between 0.6-3.6 m/min were achieved. Hole diameters varied from 7.6-9.2 cm in surface tests at bit thrusts of 1360 kg. A hole was then drilled and maintained in relative alignment within the coal seam for a distance of 640 m. Thrust levels had to be lowered to between 363-680 kg across the bit. Because the loads were smaller than those used in the surface trial, advance rates in the hole were of the order of 10-38 cm/min. The thrust level was lowered since it was found that the level of the thrust controlled the inclination of the drill so that, for example, a thrust of 363 kg caused the hole to incline downward, while at greater than 544 kg the hole inclined upward with the 9-cm-diam bit. Thrust levels increased 227 kg when the hole diameter was raised to 9.2 cm, although in such a case penetration rates in excess of 56 cm/min could be achieved. Horizontal Water Jet Drilling of Coal The University of Missouri-Rolla has recently undertaken research for Sandia Laboratories on the use of high pressure water jets as a means of drilling through coal. The initial experiment in this program called for drilling a hole horizontally into a coal seam from the side of a strip pit using water jets as the cutting mechanism. A very simple setup [(Fig. 1)] was used in this program and a 15-m hole was drilled at an approximate drilling speed of 1.2 m/min. The nozzle was designed so that the hole dimension was approximately 15 cm across [(Fig 2)] and the thrust was maintained at levels below 91 kg in moving the drill into the coal face. The system used was very crude and comprised a high pressure water jet drill enclosed within a 5.7-cm outer diameter galvanized water pipe to provide rigidity to the drilling system. This pipe sufficed to maintain hole alignment over the 15-m increment. While it is premature to make long-term predictions on ultimate applicability of this sytem to long hole drilling, certain inherent advantages of water jets can be delineated from research results and suggest considerable advantage to further research in development of this application. High pressure water was supplied at approximately 62 046 kPa from a 112-kW high pressure pump, with a 83 L/m flow through the supply line to the nozzle. The drilling system consisted of a nozzle rigidly attached to the front end of the galvanized piping. High pressure fluid was supplied to this nozzle through a flexible high pressure hose that fed from the nozzle back through the galvanized pipe to a rotary coupling attached

Jan 1, 1981

Page Bronze Bearing Metals. By G. H. Clamer............... 162 Pennsylvania Railroad Anti-friction and Bell Metals. By F. M. Waring .. 166 The Tin-plate Industry. By D. M. BUck. Discussed by G. H. ClameR, J. W. RICHARDS............................ 168 The Aluminum Bronze Industry. By W. M. Corse............ 171 Bronzes, Bearing Metals, and Solders. By G. K. BURgess and R. W. Woodward. Discussed by G. H. Clamer, R. T. Roberts......... 175 Babbitts and Solder. By G. W. Thompson................ 184 The Cadmium Supply of the United States. By C. E. Siebenthal. Discussed by M. L. Lissberger, C. W. Hill, F. F. ColcoRd.......... 185 Solder, Its Use and Abuse. By M. L. LissbergeR............ 192 Bronze Bearing Metals G. H. ClameR,* Philadelphia, Pa.—Unfortunately, prior to the war no serious attention was given to the conservation of tin, notwithstanding that this country is practically dependent upon outside sources for its entire tin supply. Tin is of vital importance in many industries, but it is surprising how many and how excellent are its substitutes when we become acquainted with them. Tin has always been a relatively high-priced metal, and it is part of the human attitude to associate high prices with high standards; it is not until the price of a commodity becomes well-nigh prohibitive that we hunt for substitutes, because the idea of substitution seems always to involve an assumption that the substitute must necessarily be inferior. The history of the development of bearing bronzes is a striking example of this policy. In the early days, copper-tin alloys were almost universally used, the idea then being prevalent, which is still held by many, that a bearing to resist wear must be hard, and the harder the better. The favorite bronze bearing contained 90 per cent. copper and 10 per cent. tin; frequently, in service which was considered severe, even higher proportions of tin were used. Such hard alloys have great resistance to compression, but as a rule they had a very wide factor of safety in this

Jan 1, 1919

By O. A. Knight, Helmut Muller-Stock

The suppression of the austenite-martensite transformation that can be brought about by the addition of certain alloying elements, such as manganese or nickel, to plain carbon steel has been known for a long time, especially since Guillet&apos;s investigation at the beginning of this century. The extent to which the critical range is lowered depends upon the percentage and nature of the special element added. First the Arl point is lowered gradually, then at a certain percentage a sudden lowering to about 300" C. occurs. The addition of still larger percentages of the alloy may result in lowering the Ar, point to room temperature or below, in which case the steel remains austenitic at room temperature, especially after rapid cooling. The effect of alloying elements of this general type on the lowering of the transformation temperature is well illustrated by Sauveur(lJ$ in his Fig. 281a, reproduced here as Fig. 1. This type of curve is characteristic of both manganese and nickel though it requires about 21/2 times as much nickel as of manganese to produce the same result. The influence of nickel in retarding the transformation of austenite into the lower transition constituents is due to its lowering of the critical range of the steel, which is also well illustrated by Sauveur&apos;l) (after Osmond) in his Fig. 284, reproduced here as Fig. 2. Scott(&apos;" presents a diagram illustrating the effect of manganese on the Ac3 and Ara points which is strikingly similar to the diagram above referred to in Fig. 2 concerning the effect of nickel. Lowering the critical range has the effect of increasing the viscosity, or, rigidity, of the alloy at the time when it is undergoing its transformation, which greatly slows down the transformation reaction velocity, and this, in turn, makes it easier to suppress, wholly or in part, the transformational changes. Reaction rates are normally much slower at low

Jan 1, 1934

By Morris Cohen

Within the past two years, a number of publications have called attention to the double peaks, or stages, that appear in the hardness and strength curves of certain aging alloys. The author has shown the existence of double hardness peaks during the aging of a high-purity silver-copper alloy;&apos; and on the basis of electrical resistance, microscopic, dilation and lattice-parameter measurements, hc concluded that the initial hardness peak occurs prior to precipitation while the secondary hardening is due to precipitation. It was suggested that the general mechanism of age-hardening involves two consecutive processes, the first consisting of nucleus or knot2 formation, and the second consisting of actual precipitation and particle growth. It was further held that the two stages are interdependent, but because of nonuniform precipitation they may overlap each other to an extent that increases as the aging temperature is raised. At high aging temperatures, the effect of the first stage cannot be detected because of the rapid occurrernce of precipitation. The general theory of age-hardening recently presented by Dr. M. L. V. Gayler3 is in close agreement with the picture outlined above. With reference to work done on duralumin, copper-beryllium and copper-silver alloys, Dr. Gayler also concluded that age-hardening takes place in two consecutive steps: first, diffusion (in which the solute atoms migrate to certain crystallographic planes), and then precipitation. However, W. L. Fink and D. W. Smith4 have shown that the double aging peaks that appear in the strength curves of high-purity aluminum-copper alloys may be explained without recourse to pre-precipitation phenomena. By means of very careful metallographic technique, Fink and Smith demonstrated that during aging the precipitation takes place at an accelerated rate along the grain boundaries and slip planes as a result of the plastic deformation caused by the drastic quench from the solution heat-treatment temperature. The general precipitation occurs at a

Jan 1, 1939

By Morris Cohen

Within the past two years, a number of publications have called attention to the double peaks, or stages, that appear in the hardness and strength curves of certain aging alloys. The author has shown the existence of double hardness peaks during the aging of a high-purity silver-copper alloy;&apos; and on the basis of electrical resistance, microscopic, dilation and lattice-parameter measurements, hc concluded that the initial hardness peak occurs prior to precipitation while the secondary hardening is due to precipitation. It was suggested that the general mechanism of age-hardening involves two consecutive processes, the first consisting of nucleus or knot2 formation, and the second consisting of actual precipitation and particle growth. It was further held that the two stages are interdependent, but because of nonuniform precipitation they may overlap each other to an extent that increases as the aging temperature is raised. At high aging temperatures, the effect of the first stage cannot be detected because of the rapid occurrernce of precipitation. The general theory of age-hardening recently presented by Dr. M. L. V. Gayler3 is in close agreement with the picture outlined above. With reference to work done on duralumin, copper-beryllium and copper-silver alloys, Dr. Gayler also concluded that age-hardening takes place in two consecutive steps: first, diffusion (in which the solute atoms migrate to certain crystallographic planes), and then precipitation. However, W. L. Fink and D. W. Smith4 have shown that the double aging peaks that appear in the strength curves of high-purity aluminum-copper alloys may be explained without recourse to pre-precipitation phenomena. By means of very careful metallographic technique, Fink and Smith demonstrated that during aging the precipitation takes place at an accelerated rate along the grain boundaries and slip planes as a result of the plastic deformation caused by the drastic quench from the solution heat-treatment temperature. The general precipitation occurs at a

Jan 1, 1939

By W. H. Triplett

THE purpose of this paper is to record a few field observations and accumulated office data concerning outcrops, relation of ore occurrences to intrusive and host rock, and mineral zoning. Reasons for some of the phenomena are not clear to the author so the facts are given with the hope that other investigators may be able to furnish the explanations. The Avalos unit of the Compania Minera de Penoles, S. A., operates the Alicante, Bonanza, Providencia, Albarradon, San Eligio, Nazareno, Leona, Salaverna, and Santiago mines situated between Avalos railroad station and Concepcion del Oro on the Coahuila and Zacatecas railroad in the State of Zacatecas, Mexico. Some of these mines are within Penoles property while others are on mining claims leased from the Compania Nazareno, y Catasillas, S. A., Mazapil Copper Co., and the American Smelting and Refining Co. The main office and camp are at Providencia, about 170 km southwest of Monterrey, N. L., so the silver-lead-zinc mines of the district are usually referred to as the Providencia mines. The Aranzazu, Catarroyo, and Cabrestante copper-gold. mines are situated a few kilometers to the southeast on the same mountain range near Concepcion del Oro, the name by which the camp is known. It is operated by the Mazapil Copper Co. The main theme in the following pages is a description of the silver-lead-zinc ore occurrences of the district. Rock Formations Sedimentary Rocks: Many competent geologists have contributed generously to an ample fund of information concerning the sedimentary columns of northern Mexico. Among them are Carlos Burckhardt, E. Böse, L. B. Kellum, .and R. W. Imlay. Carlos Burckhardt who covered a number of extensive areas in many parts of the Mexican Republic, devoted years to mapping the geology of the Caja, Zuloaga, and Santa Rosa mountain ranges around Mazapil, Concepcion del Oro, and San Pedro de Ocampo, Zacatecas. He did most of the original mapping which has been used as a basis and amplified by others. C. E. Burbridge and, more recently, John

Jan 1, 1952

By C. E. Beecher

The application of gas or air under pressure to obtain more oil from a sand which has been practically exhausted by ordinary production methods has been practiced to a limited extent for many years. Until recently such methods were confined to the Eastern fields, principally those of Ohio and West Virginia, where in many cases the production obtained after applying pressure for a few years was nearly equal to the total production prior to that time which had been obtained by the usual production methods. As early as 1917, J. 0. LewisL called attention to this method of increasing the recovery of oil and cited the phenomenal results obtained by H. E. Smith, I. L. Dunn and 0. C. Dunn, who pioneered the application of air or gas pressure recovery methods. With this information available it would appear that other oil-producing sections of the country have been extremely slow to realize the advantages of repressuring. However, after a few successful projects in the Mid-Continent area, the oil producers appreciated t&apos; e value of this method for obtaining further and profitable production from their practically exhausted leases and are now making extensive use of it. In general, it has been the practice to apply pressure to the sands when production has declined to a small yield per well. The purpose of this paper is to discuss some of the advantages which may be expected from returning gas under pressure to the oil sands during the early stages of development, before the rock pressure has been dissipated and the gas exhausted, and to stimulate discussion of this subject on which comparatively little actual field data are available. The Function of Gas Gas associated with or dissolved in the oil is the source of energy causing movement of the oil to the well. When this energy is dissipated production ceases. The exception to this general statement is found in fields where hydrostatic water pressure may supply energy after the gas

Jan 1, 1929

By Morris Cohen

WITHIN the past two years, a number of publications have called attention to the double peaks, or stages, that appear in the hardness and strength curves of certain aging alloys. The author has shown the existence of double hardness peaks during the aging of a high-purity silver-copper alloy;1 and on the basis of electrical resistance, microscopic, dilation and lattice-parameter measurements, he concluded that the initial hardness peak occurs prior to precipitation while the secondary hardening is due to precipitation. It was suggested that the general mechanism of age-hardening involves two consecutive processes, the first consisting of nucleus or knot2 formation, and the second consisting of actual precipitation and particle growth. It was further held that the two stages are interdependent, but because of nonuniform precipitation they may overlap each other to an extent that increases as the aging temperature is raised. At high aging temperatures, the effect of the first stage cannot be detected because of the rapid occurrence of precipitation. The general theory of age-hardening recently presented by Dr. M. L. V. Gayler3 is in close agreement with the picture outlined above. With reference to work done on duralumin, copper-beryllium and copper-silver alloys, Dr. Gayler also concluded that age-hardening takes place in two consecutive steps: first, diffusion (in which the solute atoms migrate to certain crystallographic planes), and then precipitation. However, W. L. Fink and D. W. Smith4 have shown that the double aging peaks that appear in the strength curves of high-purity aluminum-copper alloys may be explained without recourse to pre-precipitation phenomena. By means of very careful metallographic technique, Fink and Smith demonstrated that during aging the precipitation takes place at an accelerated rate along the grain boundaries and slip planes as a result of the plastic deformation caused by the drastic quench from the solution heat-treatment temperature. ? The general precipitation occurs at a

Jan 1, 1938

By Galen H., Clevenger

THE first and most important thing that affects the majority of lead producers in the Rocky Mountains and the western mining regions is that zinc in an ever-increasing degree is inseparably associated with the lead. The Sullivan mine in British Columbia is not only a great lead mine, but also a great zinc producer. This mine could not reach its full measure of productiveness, nor was its great value established, until a reasonably good physical method was developed for separating the lead from the zinc prior to the recovery of each metal by an appropriate process. The western metallurgists and also metallurgists in other parts of the world have long faced the lead-zinc problem. This for many years stimulated a great deal of experimental work looking toward the development of a physical or chemical method of separating lead and zinc in concentrated form from complex ores. Space will not permit of going into this work in detail, but it is sufficient to say that with but few exceptions the western lead smelter continued smelting charges many times too high in zinc for the most efficient operation of lead furnaces. The zinc was not only lost, as the zinc content of many a western slag dump bears mute testimony, but the cost of lead smelting was increased by reason of the presence of the zinc. The owner of the ore under these circumstances could be paid nothing for the zinc and, indeed, he was penalized for it

Jan 1, 1926

Discussion of the paper of Frank H. Kneeland, Safeguarding the Use of Mining Machinery. By B. F. Tillson and Arthur Williams. 1073 Discussion of the paper of Howard N. Eavenson, Safety Methods and Organization of United States Coal & Coke Co. By William H. Grady, Thomas W. Dawson, C. W. Goodale, J. Parke Charming, B. F. Tillson, George S. Rice, Arthur Hovey Storrs, Harry H. Stoek, Lawson Blenkinsopp, Arthur Williams, and Howard N. Eavenson. 1075 Discussion of the paper of J. Parke Channing, Enlarging the Worth of the Worker and the Perspective of the Employer. By Fred H. Rindge, Jr., S. A. Taylor, Elmer L. Corthell, and Philip W. Henry. . 1095 Discussion of the paper of Walther Mathesius, High Blast Heats in Mesaba Practice. By Joseph W. Richards, W. A. Forbes, J. E. Johnson, Jr., H. P. Howland, and Walther Mathesius. . 1100 Discussion of the paper of W. R. Shinier, Effect of Finishing Temperatures of Rails on Their Physical Properties and Microstructure. By William R. Webster, Henry M. Howe, A. A. Stevenson, G. K. Burgess, and Samuel L. Hoyt . 1107 Discussion of the paper of George K. Burgess and Sir Robert A. Hadfield, Sound Steel Ingots and Rails. By Albert Sauveur, Henry M. Howe, Henry D. Hibbard, Joseph W. Richards, F. W. Wood, and George K. Burgess. . 1112 Discussion of the paper of Henry M. Howe and Arthur G. Levy, Are the Deformation Lines in Manganese Steel Twins or Slip Bands? By J. E. Stead 1116 Discussion of the paper of F. C. Langenberg and R. G. Webber, Structures and Hysteresis Loss in Medium-Carbon Steel. By Henry M. Howe. . . 1117 Discussion of the paper of Charles H. MacDowell, German and Other Sources of Potash Supply. By George S. Rice, Charles H. MacDowell, and V.C. Grubnau . . 1118 Discussion of the paper of Joel H. Watkins, White-Burning Clays of the Southern Appalachian States. By H. Ries 1120

Jan 5, 1915