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By V. B. Kurfman

Grain refinement of Mg-Al melts by carbonaceous additions has been attributed to nucleation by aluminum carbide. The effects of process and alloy variables are interpreted and predicted in terms of the dispersion and chemistry of this phase. The grain coarsening action of Be, Zr, Ti, R.E., chlorination, temperature extremes, and prolonged holding times is described. Measures necessary to insure an adequate dispersion of the catalyst are discussed. CARBON inoculation treatments have become fairly well known and used for grain refinement of magnesium alloys containing Al. Although there is general agreement that a nucleation process occurs, the process is not understood and the inoculants are used in a rather empirical fashion. The treatment is applied to the class of alloys containing 3 to 10 pct Al, i.e., AZ31A to AM100A. Typical methods involve melting, alloying, and adjusting the temperature to 1400° to 1450°F. Then 0.01 to 0.5 pct C as CaC2, C6C16, or lampblack is added by any convenient means, and the melt poured within 10 to 30 min. Investigators generally have been impressed by an assumed similarity of this refinement process to superheat grain refinement, which depends on heating approximately the same alloys to a temperature in the range of 1550" to 1650°F, then pouring promptly after the melt is cooled to the pouring temperature. Various predictions have been made that carbon refinement would replace superheating in commercial practice due to reduced process costs, but this replacement has not fully taken place because of production difficulties and conflicting observations. Davis, Eastwood, and DeHaven1 agree with Nelson2 and wood3 in suggesting that an excess of inoculant may be harmful. Wood however says that overtreat-ment is not a problem in production use of hexa-chlorobenzene inoculation, and Hultgren and Mitchell4 claim no evidence of harm from excess additions. Various grain coarsening reactions are known to occur, including the possibility of overtreatment mentioned above. Trace amounts of Be,2 Zr, and Ti may prevent refinement by either a carbon treatment or a superheat. Occasionally treatment with cl25 may cause coarsening, although the Battelle refinement process' uses a CC14-C12 blend. Grain coarsening also tends to occur on holding at temperatures below 1350°to 1400°F, especially after a superheat treatment, and for this reason Nelson2 stresses the desirability of a refinement method useful at lower temperatures for open pot melting practice. Since a carbon treatment can be made to work at temperatures below 1400°F, it seems desirable to investigate the mechanism of the refinement and the mechanisms of the coarsening reactions in order to establish control conditions for use in commercial production. The identity of the nucleating phase must first be established and then the factors affecting its chemistry and physical dispersion must be determined. THE IDENTITY OF THE NUCLEATING PHASE Davis, Eastwood, and DeHaven suggested that the nucleating phase in this system is Al4c3,1 but Mahoney, Tarr, and LeGrand8 disagree, largely because they found no evidence of the compound in alloys after carbon treatment and because there is no indication that aluminum carbide should be unstable over the temperature range used in the superheat treatment. This latter objection is based on the assumption that both the carbon treatment and the superheat treatment introduce the same nuclei. Electron diffraction studies have been made to identify the nucleating phase. Samples of grain refined A292 have been selectively etched SO that clean surfaces are obtained and so that secondary phases are in relief. Electron diffraction patterns from these surfaces have established that the carbon treatment of A292 introduces into the metal a large number of small, plate-like particles with a structure very similar to Al4C3. In most cases, the plate-like nature of the particles prevented positive identification but in the cases where the identification could be made the particles proved to be AIN A14C3. However, enough variation in lattice constants was observed so that all compositions from pure A14C3 to the 50:50 solid solution A1N.Al4C3 were probably present.14 In A14C3 and especially AlN.Al4C3 the A1 atoms occur in layers within which they have the same hexagonal symmetry and spacing as the Mg atoms in a single basal plane of a magnesium crystal. The solid solution spacing lies between the 3.16 of AIN and the 3.3? for Al4C3, in satisfactory agree-

Jan 1, 1962

By C. A. Heiland, Tripp R. M., Dart Wantland

This paper serves to illustrate the application of geophysics to a virtually abandoned mine properly, an application that led to the discovery of an ore body and thus afforded an Opportunity to cOmpare subsequent geologic findings with geophysical data. The work herein described represents, however: more than mere ''case history." It demonstrates that it is possible to obtain satisfactory results by simple means and relatively inexpericnced personnel. The geophysical surveys were made by students as a part of their field assignments in the course of their regular training, and were supervised by Dart Wantland, J. E. Hawkins and R. Maurice 'Tripp. In the course of several seasons an appreciable amount of material was accumulated, which gave graduate students an opportunity for special studies. In this connection, the contributions by L. Massé, R. C. Hyslop, and J. E. Hawkins deserve special mention. The property owners cooperated wholeheartedly in the work, and special thanks are due messrs. J. F. Johnson and S. E. Zelenkov, of the American Smelting and Refining Co., for their interest and for permission to utilize the results of their development work for this publication. Location and Geology The Malachite mine is situated on the northcrn slope of Bear Creek Canyon, 4 miles northeast of Evergreen, I½ miles northwest of Idledale, and 4% miles west northwest of Morrison, in Jefferson County, Colorado. The location (Fig. I) is north of the center of set. 30, T. 45, R. 70 W., at an elevation of about 7500 ft, above sea level, Near the mine the terrain slopes rather uniformly southward at an angle of about 180 pigs. 3 and 7). The geology of the Malachite mine area has been described by J, underhill,' W, Lindgren,2 and J. Boyd.3,4 A map showing surface outcrops and mine workings appears in Fig, 2. the Malachite mine is in an amphibolite belt enclosed in gneisses and schists of the Idaho-Springs formation (probably early Algonkian age). The highly contorted beds are nearly vertical and strike slightly north of west. A series of granite-pegmatite dikes have been intruded almost at right angles into the gneisses and schists and doubtedless are postmineral. While most of the formations are exposed at the surface, a part of the 'lope is covered by slide rock and float, and in the eastern portion by alluvium and creek fill. A quartz-diorite dike cuts through the amphibolite schists at a small angle with nearly vertical dip. The copper sulphides, developed in this dike by magmatic segregation, occur in lenticular form. As far as the mine workings have revealed, the ore lenses are often discontinuous in depth and

Jan 1, 1946

By Tripp R. M., C. A. Heiland, Dart Wantland

This paper serves to illustrate the application of geophysics to a virtually abandoned mine properly, an application that led to the discovery of an ore body and thus afforded an Opportunity to cOmpare subsequent geologic findings with geophysical data. The work herein described represents, however: more than mere ''case history." It demonstrates that it is possible to obtain satisfactory results by simple means and relatively inexpericnced personnel. The geophysical surveys were made by students as a part of their field assignments in the course of their regular training, and were supervised by Dart Wantland, J. E. Hawkins and R. Maurice 'Tripp. In the course of several seasons an appreciable amount of material was accumulated, which gave graduate students an opportunity for special studies. In this connection, the contributions by L. Massé, R. C. Hyslop, and J. E. Hawkins deserve special mention. The property owners cooperated wholeheartedly in the work, and special thanks are due messrs. J. F. Johnson and S. E. Zelenkov, of the American Smelting and Refining Co., for their interest and for permission to utilize the results of their development work for this publication. Location and Geology The Malachite mine is situated on the northcrn slope of Bear Creek Canyon, 4 miles northeast of Evergreen, I½ miles northwest of Idledale, and 4% miles west northwest of Morrison, in Jefferson County, Colorado. The location (Fig. I) is north of the center of set. 30, T. 45, R. 70 W., at an elevation of about 7500 ft, above sea level, Near the mine the terrain slopes rather uniformly southward at an angle of about 180 pigs. 3 and 7). The geology of the Malachite mine area has been described by J, underhill,' W, Lindgren,2 and J. Boyd.3,4 A map showing surface outcrops and mine workings appears in Fig, 2. the Malachite mine is in an amphibolite belt enclosed in gneisses and schists of the Idaho-Springs formation (probably early Algonkian age). The highly contorted beds are nearly vertical and strike slightly north of west. A series of granite-pegmatite dikes have been intruded almost at right angles into the gneisses and schists and doubtedless are postmineral. While most of the formations are exposed at the surface, a part of the 'lope is covered by slide rock and float, and in the eastern portion by alluvium and creek fill. A quartz-diorite dike cuts through the amphibolite schists at a small angle with nearly vertical dip. The copper sulphides, developed in this dike by magmatic segregation, occur in lenticular form. As far as the mine workings have revealed, the ore lenses are often discontinuous in depth and

Jan 1, 1946

By F. Garofalo

It has been shown by various investigators that during constant stress creep the dependence of minimum creep rate, 6,, on stress, o, is given by em = A onat low stress levels, md by 6, = A' exp [ß s] at high stress levels. In these relations A, n, A', and ß are constant at constant temperature. A single relation has been found which satisfies conditions for both high and low stresses and agrees well with experimental results. This relation is 2, = AN (sinh a s)n, where A" is a constant at constunt temperature and a = p/n. This relation also satisfies the linear relation, 6, = k s, found at temperatures near the melting point at low stresses. EXPERIMENTAL creep results have led to a number of empirical relationships between minimum creep rate, 6,, and the applied stress, s. Under conditions of constant stress it is generally found that at low-stress levels,'-' the dependence of minimum creep rate is given by 6, = Asn. At high-stress levels'74 the experimental results fit the relation, 6, = A' exp [po l. In these relations A, n, A' and ß are constant at constant temperature. A model based on climb-of-edge dislocations from a pile-up array leads to a relation similar to that found experimentally at low stresses.' On the other hand. theories based on chemical-reaction rate,5 nonconservatively moving dislocation jogs, and jog migration and climb-of-edge dislocations4 lead to a relation similar to that found experimentally at high stresses. No difference in mechanism between low and high stress levels has been clearly defined; it is questionable whether such a difference really exists. In any event, the major argument usually given in substantiation of a change in mechanism from low to high stresses is that no single relation exists for defining the stress dependence of the creep rate over wide ranges in stress. However, such a relation has been found and is of the form, dm = A" (sinh a s)n, where A" is a constant at con- stant temperature and a = ß/n. This relation agrees well with experimental results over wide ranges in stress and temperature for copper, aluminum, an A1-3.1 pct Mg alloy, and an austenitic stainless steel. STRESS DEPENDENCE OF MINIMUM CREEP RATE At low stress levels the minimum creep rate, gm, depends on the stress, 0, under conditions of constant stress creep through the relation em=Aon [1] The quantities A and n have been defined previously. In the range in which this relation applies, a linear dependence is found in a log em,-log o plot. Above the stress range of application of relation [I], the minimum creep rate increases much mar; rapidly than predicted by relation [I]. This behavior is shown in Fig. 1 for a series of creep tests on copper4 at various temperatures ranging from 673 o to 973°K. Relation [I] is satisfied at the lower stresses, although the results at 973°K are quite limited. In all cases the transition beyond the applicable range of relation [I] is a gradual one indicating no abrupt change in mechanism. For all test temperatures, values of n have been determined from the results in Fig. 1. These are reported in Table I under Alog tm/hlog o. At high stress levels the stress dependence of minimum creep rate under conditions of constant stress is given by im = A' exp [ß a] 2] All factors have been defined previously. In a log em-0 plot, relation [2] predicts a linear function. Experimentally, a pronounced deviation from the prediction of relation [2] is found at lower stresses. As the stress is lowered, the minimum creep rate decreases more rapidly than predicted by relation [2]. This shown for copper in Fig. 2. Again it is found that the transition from high to low stresses is gradual and no really sharp change is found. Values of p determined from the high stress results are given in Table I. The dependence of minimum creep rate on stress at constant temperature for all ranges in stress

Jan 1, 1963

By M. D. Arnold, P. B. Crawford, P. C. Hall

An experimental study has been made to determine the optimum flooding pressures for four different oils. The oil formation volume factors ranged from 1.08 to 2.13, and solution gas-oil ratios ranged from about 200 cu ft/bbl to 2,250 cu ft/bbl. Viscosities ranged from 0.38 to 0.95 cp at the respective bubble points of the fluids and from 0.7 to 20 cp at atmospheric pressure. Water floods were conducted at various pressure levels from run to run. The recovery as a function of flooding pressure was found to be different for each fluid, with optimum gas saturations ranging from 7 up to 35 per cent. The data indicate that substantially higher recoveries may be obtained if water floods are conducted at an optimum pressure and that this optimum pressure is a function of fluid properties. The same core was used for all tests, and the reproduction of saturations for various runs indicates that wettability in the predominantly water-wet core did not change. INTRODUCTION A paper was presented by Bass and Crawford' which described an experimental study of the effects of flooding pressure and rate on oil recovery by water flooding. This work was conducted using high-pressure models operated in a manner similar to that of an actual reservoir, with gas saturations being obtained by a solution-gas-drive mechanism. They found that the greatest oil recovery was obtained for the system studied by flooding in the presence of a 5 to 7 per cent gas saturation. Another experimental study simulating field conditions was presented by Richardson and Perkins.' They used an unconsolidated sand pack containing kerosene-natural gas fluid and interstitial water. They flooded at various pressures and flooding rates. For their system it was found that the recovery was independent of the pressure level at which the water flood was performed. Kyte, et al," found that oil recovery by water flooding was increased as the free gas saturation at waterflood initiation was increased. However, after the initial gas saturation was increased above 15 per cent, the increase in oil recovery tended to level off. All of their runs were made at the same pressure using a light oil saturated with helium. The desired gas saturation was obtained by injecting helium into the core. Dyes' made calculations which showed that an optimum gas saturation of 12 to 14 per cent may result in an increase in oil recovery of 7 to 12 per cent over that obtained by flooding at the bubble-point pressure. Others have also found that the presence of a free gas saturation may increase the waterflood oil recovery. In each case shrinkage was small and changes in fluid properties with respect to pressure were small. A careful review of the literature reveals that at the present time there is a wide difference of opinion on the factors affecting waterflood recoveries. This diversity of opinion is probably due to the fact that very little research has been done which has taken into account the many variables existing in an actual field being water flooded. Since the literature contains little information on high-pressure waterflooding studies using various types of reservoir fluids, it was believed appropriate that such a study should be made. EQUIPMENT AND PROCEDURE All tests were made using the same consolidated sandstone core. Torpedo sandstone was used to turn a cylindrical core 13.5-in. long and with a 2.92-in. average diameter. The core had a porosity of 28 per cent and a permeability to brine of 146 md. This brine was made up by adding 20,000-ppm sodium chloride and 30,000-ppm sodium nitrite to distilled water. This was used as connate water and flooding water. No fresh water was ever brought in contact with the core, as tests showed the sandstone contained argillaceous material which swelled in the presence of fresh water and plugged the stone. The core was sealed in a section of 6-in. N-80 tubing with Woods metal filling the annulus. The core was mounted horizontally; an injection well was placed in the center of one end and a production well in the center of the other. Pressure control was maintained by placing a back-pressure regulator (upstream control) on the producing well. The "live" oil was stored in a separate bottle and water was injected into this bottle to displace the oil for saturating the core using a two-cylinder standard-proportioning pump. This same pump was used for water flooding the core at a constant rate. This system was enclosed in water jackets and the temperature was automatically main-

By Robert L. Frantz

Progress and improvement continue to be the bywords of a dynamic coal industry. The industry continues to gain strength and expand its horizons in the face of competition from atomic energy and the problems of restrictive legislation. The direct contribution of coal mining and transportation to the national economy is about $3 billion a year ac- cording to a study made by the National Coal Policy conference. Coal remains the backbone of the power industry producing almost two-thirds of all the electrical energy generated by fossil fuels and one-quarter of all the energy consumed in the nation. Power supplied by electric utilities increased 6.9% last year. The chairman of the Federal Power Commission predicted a 7.5% growth rate until 1980 for the nation's electric output. Some 80,500 MW of fossil fired power plant capacity are on order or under construction before 1974, compared to a present capacity, all sources, of about 290,000 MW. The comparable new additions of nuclear power plants is expected to total about 51,000 MW.

Jan 2, 1969

By O. W. Ellis

THE question of the influence of gases upon the properties of copper has received the attention of a number of investigators, among whom Sieverts,1 Iwasé,2 Lobley and Jepson3 stand preeminent. SOLUBILITY OF . GASES IN. COPPER Sieverts and Iwasé concerned themselves with the solubility of a variety of gases in the metal in the solid and liquid states. They determined the absorption coefficients of these gases and in all cases found a sharp change in solubility at the melting point of the metal. In this respect they disagree with Lobley and Jepson, who have based their opinions upon the appearance of small ingots of the metal which had been fused in an atmosphere of one or other of three gases and had then been rapidly cooled, while surrounded by gas, to the freezing point (rate-possibly 30° to 60° C. per sec.). The ingots that had been fused and cooled under nitrogen and carbon monoxide were free from blowholes and it was assumed that these gases were not absorbed in amounts much in excess of those which would dissolve in the solid metal; the ingots similarly treated under hydrogen were full of blowholes and it was assumed in this case that gas was ejected on solidification of the copper. The effect of varying the rate of freezing upon the character of the test ingots was not examined by these investigators; otherwise, it is felt, their views might have been subject to modification. Sieverts' most important contribution is that the solubility of a gas in any metal is proportional to the square root of its pressure or concentration. Knowing then the absorption coefficients of the various gases in copper, it should be possible to determine the analysis of the

Jan 1, 1928

By Frederic Benard

RECOVERY of selenium and tellurium at Copper Cliff by the Ontario Refining Co. has been previously described by the writer.1 During 1935 a new building was erected to house this operation and description of the new plant and process form the subject of this paper. The building, of modern steel and tile construction, covers an area of 5900 sq. ft. with a volume of approximately 165,000 cu. ft. The large monitored center bay is flanked by two smaller outside bays, one of which is devoted to the tellurium section. All equipment, ceilings and upper walls, are treated with aluminum paint, giving good illumination and facilitating good housekeeping, essential from a health standpoint in handling material of this nature.

Jan 1, 1938

By G. Wakefield, A. H. Daane, D. H. Dennison, F. H. Spedding

Preparation of pure scandium metal was accomplished by calcium reduction of the fluoride by two methods; a low-temperatzdre alloy process and direct reduction with subsequent distillation of the product. The following properties were determined: melting point: 1181OK; boiling point (calculated): 3000°K; lattice constants at 298°K (hexagonal lattice): a = 3.308 * 0.001 A, c = 5.267 * 0.003A; calculated density at 298°K, g per cm3: 2,990 + 0.007; electrical resistivity, ohm-cm: 299°K, 66.6 ± 0.2 x 10 -6; 373oK, 77.4 * 0.2 x 10 -6; thermal coefficient at 299°K, ohm-cm per deg: 5.4 X x; heat of sublimation at 298°K, kcal pel- mole: 80.79. The vapor pressure was determined as a function of temperature between 1505o and 1748°K, with the data fitted to a straight line shielding the equation: Log Pmm = -1.718 X 104/ToK + 8.298. SCANDIUM, element number 21, was first discovered by Nilson in 1879 and was recognized as the Ekaboron as predicted by Mendeleff. As it is in group III of the periodic table, the general properties are a little like aluminum and also resemble quite closely the properties of yttrium and the rare-earth metals, in both the metallic and ionic form. Although the earth's crust contains approximately 5 ppm of scandium (the element is as abundant as arsenic and twice as abundant as boron) it generally occurs so widely distributed that it has earned the reputation of being very rare. The one exception to this is the mineral thortveitite, which has been found in Madagascar (20 pct Sc2O3) and in Norway (35 pct Sc2O3). Scandium also occurs in small but distinct amounts in uranium and rare-earth ores; the recent larger scale processing of these materials has made some scandium available from these sources. As with other naturally-occurring monoisotopic elements (except Be), scandium contains an odd number of protons and an even number of neutrons. Scandium metal was first prepared by Fischer and coworkers1 in 1937 by electrolysis of scandium chloride in a molten eutectic mixture of lithium and potassium chlorides, using molten zinc as a cathode and collector of the scandium metal produced. The zinc was removed from the Zn-2 pct Sc alloy by vacuum distillation, leaving a product reported to be 94 to 98 pct Sc, with the main impurities being iron and silicon. They reported a melting point of 1400° C for this material. Scandium has also been prepared by the reduction of scandium chloride with potassium metal in a glass apparatus by Bommer and Hohmann in 1941,' resulting in a mixture of metal and potassium chloride; these workers did not isolate the metal proper, but the X-ray diffraction of the slag-metal mixture showed it to be hexagonal with a = 3.30A, c = 5.45A. petru3, 4 and coworkers have recently reported the preparation of the metal in a compact form by the reduction of either ScF3 or ScC13 with calcium metal and subsequent distillation of the product. This process probably yielded a metal of high purity, but they list no chemical analysis nor do they list any of the properties of their product. Previous related work in this Laboratory has been concerned with the production of yttrium and the rare-earth metals and the determination of their physical properties. Because of its similarity to these metals, scandium is being included in this study. PREPARATION OF SCANDIUM METAL The preparation of yttrium and the rare-earth metals may be accomplished by reduction of their fluorides with calcium metal in tantalum crucibles.5 This process leads to the introduction of tantalum (up to 0.5 pct) as an impurity in the higher melting rare earths, but since the tantalum occurs as dendrites, uncombined with the rare-earth metals, its presence is not objectionable in some cases. The preparation of scandium metal in this manner, however, was found to yield a product containing 2 to 5 pct Ta. To obtain a purer product, the following two methods were developed for the reduction of scandium fluoride with calcium metal: i) a low-temperature process utilizing zinc to form a low

Jan 1, 1961

By H. F. Korman, M. C. C. Mow, P. K. Dai

INTRODUCTION Detonations of high explosives in soil and rock have been used frequently in civil engineering applications. Of particular interest in recent years has been the development of test methods to simulate the desired blast and shock environments for the testing of protective structures. The United States Air Force, in particular, the Air Force Weapons Laboratory, in conjunction with the Defense Atomic Support Agency, has in recent years, developed special technology for simulation testing of protective structures in soil and rock media. Such a technology, although initially developed for military applications, is rapidly finding its way into civil applications. One of the major problems in the design of the simulation test is the correct prediction of ground motion induced by the detonation of high explosives. This paper presents a useful prediction method which is developed specifically for ground motion in rock that is induced by the detonation of a buried planar array of explosive columns (See Figure 1). The technique of simulating shock environment using such an array is called the Direct Induced High Explosive Simulation Tech- nique (DIHEST). Normally, each shot hole may contain canisters of ammonium nitrate positioned at various depths, or a slurry explosive with detonators positioned along its length (See Figure 1). The depth and width of the array, the spacing of shot holes, the spacing of detonators, the degree of containment, and the charge weight are the variables which govern the induced ground motion

Jan 1, 1971

By Louis Moyd

The Concrete Research Division, U.S. Corps of Engineers, has developed a simple procedure for determining the coefficients of linear thermal expansion of rocks by means of resistance wire (SR-4) strain gauges. Gauges are cemented to the surfaces of specimens, which are then brought alternately to temperatures of 35OF and 1350F. Results are accurate to the seventh decimal place. IN the course of investigations of the thermal properties of various rocks proposed for use as aggregates in concrete structures, a relatively rapid method of determining coefficients of linear thermal expansion was required. A method which proved to be satisfactory for this purpose was developed in the petrographic laboratory of the Concrete Research Division, U.S. Corps of Engineers, at Clinton, Miss. The method is based on the fact that strain effects in a specimen can be determined by measuring variations in the resistance of an electrical conductor firmly cemented to the surface of the specimen. Equipment for the determination of strain, electrically, has been developed by the Baldwin-South-wark Division of the Baldwin Locomotive Works in Philadelphia. This equipment includes small strain gauges made of coils of resistance wire bonded between thin sheets of paper (SR-4 gauges), and a portable "Strain Indicator" which records variations in the length of the gauges in microinches per inch. Gauges of this type are now in general use for determinations of various mechanically-induced strains, but their use for the determination of coefficients of thermal expansion appears to be a new application. The advantages of the method are that the test specimens may be relatively small and require only a minor amount of preparation, that a large number of tests can be run at the same time, and that the installation and operation of the equipment is relatively simple. The method and equipment described are now in regular use for determining the coefficients of linear thermal expansion of rock samples submitted to this laboratory. Rocks which have been tested include granites, syenites, gabbros, and other igneous rocks, limestones and dolomitic limestones, sandstones, and quartzites. Specimen Preparation: To standardize the conditions of the tests, the rock specimens are sliced by diamond saw into slabs about 11/2x11/4 in. In the case of bedded or foliated rocks, three oriented slabs are cut from the same specimen, and represent, respectively, a direction in a plane of the bedding or foliation of the rock; a direction along the bedding or foliation and at a right angle to the first; and a direction across the planes of bedding or foliation. One of the large surfaces of each slab is lapped for a few minutes with No. 100 abrasive powder to remove saw scars and irregularities. The slabs are soaked in petroleum ether and then dried in an oven to remove all traces of oil picked up in the sawing

Jan 1, 1951

By Louis Moyd

The Concrete Research Division, U.S. Corps of Engineers, has developed a simple procedure for determining the coefficients of linear thermal expansion of rocks by means of resistance wire (SR-4) strain gauges. Gauges are cemented to the surfaces of specimens, which are then brought alternately to temperatures of 35OF and 1350F. Results are accurate to the seventh decimal place. IN the course of investigations of the thermal properties of various rocks proposed for use as aggregates in concrete structures, a relatively rapid method of determining coefficients of linear thermal expansion was required. A method which proved to be satisfactory for this purpose was developed in the petrographic laboratory of the Concrete Research Division, U.S. Corps of Engineers, at Clinton, Miss. The method is based on the fact that strain effects in a specimen can be determined by measuring variations in the resistance of an electrical conductor firmly cemented to the surface of the specimen. Equipment for the determination of strain, electrically, has been developed by the Baldwin-South-wark Division of the Baldwin Locomotive Works in Philadelphia. This equipment includes small strain gauges made of coils of resistance wire bonded between thin sheets of paper (SR-4 gauges), and a portable "Strain Indicator" which records variations in the length of the gauges in microinches per inch. Gauges of this type are now in general use for determinations of various mechanically-induced strains, but their use for the determination of coefficients of thermal expansion appears to be a new application. The advantages of the method are that the test specimens may be relatively small and require only a minor amount of preparation, that a large number of tests can be run at the same time, and that the installation and operation of the equipment is relatively simple. The method and equipment described are now in regular use for determining the coefficients of linear thermal expansion of rock samples submitted to this laboratory. Rocks which have been tested include granites, syenites, gabbros, and other igneous rocks, limestones and dolomitic limestones, sandstones, and quartzites. Specimen Preparation: To standardize the conditions of the tests, the rock specimens are sliced by diamond saw into slabs about 11/2x11/4 in. In the case of bedded or foliated rocks, three oriented slabs are cut from the same specimen, and represent, respectively, a direction in a plane of the bedding or foliation of the rock; a direction along the bedding or foliation and at a right angle to the first; and a direction across the planes of bedding or foliation. One of the large surfaces of each slab is lapped for a few minutes with No. 100 abrasive powder to remove saw scars and irregularities. The slabs are soaked in petroleum ether and then dried in an oven to remove all traces of oil picked up in the sawing

Jan 1, 1951

By Thomas Lane Carter

The history of mining in South Africa differs somewhat from that of other countries in the part taken by the aborigines in the development of the mineral deposits. The Spaniards in America, and the fortune-seekers of Australia and New Zealand, found large numbers of natives in these new countries, but the inhabitants did not become willing or efficient workers in the mines which the white men started. The Kaffirs of South Africa have not shown the same antipathy to labor, nor do they show any signs of dying out in the presence of the white man's civilization. They are a virile race, and so far the vices of civilization have not killed them. While it is true that the brain and skill necessary for the exploitation of the mineral resources of this sub-continent have been supplied by the white race, it is also a fact that most of the rough labor in the development of the mining industry of South Africa has been done by the Kaffirs. The Kaffir tribes differ greatly in their mental and physical capabilities. Compare, for instance, a Zulu of Natal with a Bechuana, or a Xosa of Cape Colony with some of the degenerate tribes of Central or East Africa, and you will find that they have little in common, save that their skin is black and that they do not believe in clothes. As a general rule, the tribes in the milder, healthier climates are far superior, both in mind and body, to the Kaffirs brought up in the hot malarial sections of Central Africa; and it naturally follows that the black men from the temperate zones of the country are much finer workmen than the degenerates from less favorable sections. It is universal in South Africa to speak of the Kaffirs as " boys." No matter if he is 90 years old, the Kaffir is always a a boy," and in this paper the word " boy " is synonymous with Kaffir.

Jan 1, 1909

By Leonard C. Grimshaw

The idea of bonding two dissimilar ferrous metals, and making use of both, is an old one. Tips have been brazed onto tool shanks for many years. The bonding of larger pieces to form whole bars and sheets has also been accomplished, but has received little attention in the technical literature, although a number of patents have been issued covering various methods for its accomplishment. There are three main motives behind the manufacture of composite steels. One is that the physical properties of one steel may supplement those of another; a useful, but at the same time, hard, brittle steel may be backed by a soft ductile one, or a stainless steel may be backed by a steel possessing greater strength. Another motive is direct lowering of cost; an expensive steel may be backed by a less expensive one, bringing down the cost of the piece as a whole. The third motive is an indirect lowering of cost, as when a useful steel is backed by a steel that is easier to machine, so that machining cost on a finished product is lowered considerably. Often more than one of these motives lead to a decision to use a composite steel. Previous Methods There are two methods in use that result in tolerably good bonds between ferrous metals: (1) the casting method, and (2) what we shall call the "heat-pressure" method. This "heat-pressure" method covers processes in which the bond is made between two prepared surfaces by heating them and then applying pressure. Usually sufficient pressure must be used to produce appreciable spread and elongation, or else we arc merely brazing and not truly welding. Casting methods for welding together ferrous metals have been used more than 74 years, and are described in the technical literature as applied

Jan 1, 1936

By Leonard C. Grimshaw

The idea of bonding two dissimilar ferrous metals, and making use of both, is an old one. Tips have been brazed onto tool shanks for many years. The bonding of larger pieces to form whole bars and sheets has also been accomplished, but has received little attention in the technical literature, although a number of patents have been issued covering various methods for its accomplishment. There are three main motives behind the manufacture of composite steels. One is that the physical properties of one steel may supplement those of another; a useful, but at the same time, hard, brittle steel may be backed by a soft ductile one, or a stainless steel may be backed by a steel possessing greater strength. Another motive is direct lowering of cost; an expensive steel may be backed by a less expensive one, bringing down the cost of the piece as a whole. The third motive is an indirect lowering of cost, as when a useful steel is backed by a steel that is easier to machine, so that machining cost on a finished product is lowered considerably. Often more than one of these motives lead to a decision to use a composite steel. Previous Methods There are two methods in use that result in tolerably good bonds between ferrous metals: (1) the casting method, and (2) what we shall call the "heat-pressure" method. This "heat-pressure" method covers processes in which the bond is made between two prepared surfaces by heating them and then applying pressure. Usually sufficient pressure must be used to produce appreciable spread and elongation, or else we arc merely brazing and not truly welding. Casting methods for welding together ferrous metals have been used more than 74 years, and are described in the technical literature as applied

Jan 1, 1936

By Frank C. Schrader

Page Introduction.............................. 196 Geology of the District......................... 196 Ore Deposits of the District....................... 198 Gcncral Description........................ 198 The Cerbat Mountains Group................... 199 General Description...................... 199 Tennessee Mine....................... 203 Midnight Mine........................ 203 Mineral Park........................ 204- Golconda Mine........................ 204 Other Ore-bearing Districts.................. 205 Lost Basin District ...................... 205 The Black Mountains Group.................... 206 Tom Reed-Gold Road District...................... 208 General Dcscription........................ 208 Development........................... 209 Topograplly............................ 210 Geology.............................. 210 Ore Deposits........................... 213 General Dwcription...................... 213 Zones.......................:....215 Structure of Ore Shoots.................... 217 Gold Road Mine ......................... 218 General Description...................... 218 Geology........................... 218 Ore Deposits......................... 219 Tom Reed Minc......................... 222 General Description..................... 222 • Ore Deposits.......................... 222 Development......................... 223 Character of Ore....................... 224 Other Mines........................... 224 Fields Similar to the Ton1 Reed-Gold Road District......... 227

Jan 1, 1917

By Nicholas J. Grant, A. W. Mullendore

Measurements of grain boundary sliding were made on polycrystal and bicrystal tensile creep specimens of Al-2 pct Mg at 500oand 700oF. Grain and pain boundary orientation factors were studied with respect to their effect on the magnitude and direction of grain boundary sliding. It was concluded that a large part of the observed sliding may be caused by the operation of slip crossing the grain boundaries. Supporting evidence for this model from other investigations is also given. GRAIN boundary sliding in metals during elevated temperature deformation has frequently been thought of as an independent mechanism with its own characteristic stress, temperature, and structure dependence. Further, it is common to regard the grain boundary as the weak link during creep deformation since: 1) the strength of apolycrystallinemetal, as meas-sured by creep rate or rupture life, decreases at\a more rapid rate when sliding comes into action, and 2) grain boundary sliding, as revealed by "boundary darkening" and fold formation is often the first visible deformation. On the other hand, more quantitative observations, in both polycrystals and bicrystals, have shown boundary deformation to be closely related to the over-all deformation of the specimen. The curve of grain boundary contribution to elongation vs time takes a shape similar to that of the total creep curve,',' and the apparent activation energy for sliding appears in most cases to have the same value as that for total creep.3 In order to reconcile these observations, one is left with these possibilities: 1) The grain boundary and grain deformation rates are both controlled by the same rate limiting processes. 2) The rate of sliding is limited by accommodation deformation in the grains. 3) Sliding is the consequence of grain deformation. 4) Grain deformation is dependent on prior grain boundary deformation. Alternatives 2) and 3) would view grain boundary sliding as occurring in series with another deformation process which could be rate controlling. McLean prefers item 3) as the sliding basis,4 where subgrain rotation results from dislocation accumulation in the substructure at the grain boundary. Crussard and Friedel's5 treatment of grain boundary migration considers that dislocations are forced into the grain boundary and are dissociated into dislocations with Burgers' vectors nearly parallel to the grain boundary. The movement of these partial grain boundary dislocations then produces the sliding. The results of this investigation have indicated alternative 3) to be the most appropriate and it is this aspect of grain boundary sliding which will be analyzed. EXPERIMENTAL PROCEDURE Three types of tensile creep tests were employed in this study: (I) A constant load test of one very coarsegrained polycrystalline specimen at 500° F, 3600 psi, 1 pct per/hr strain rate to examine the grain and grain boundary orientation factors in grain boundary sliding. (II) Constant strain rate tests of polycrystalline specimens at 510o and 715o F, 2 pct per/hr strain rate to determine the grain boundary contribution to elongation at very low total strains. (m) Constant strain rate tests of bicrystals of various grain and grain boundary orientations at 500°F, 2 pct per/hr strain rate to obtain further information on the orientation effects in grain boundary sliding. The material used in the tests was a high-purity Al-1'.92 mg alloy, kindly furnished by Alcoa. Its composition is given in Table I. The alloy is a solid solution at the test temperatures. The coarse grained polycrystalline specimen for test (I) was prepared by recrystallizingthe machined specimen, straining it about 1pct intension at room temperature and annealing at 900°F for 8hr. The constant strain rate specimens (11), with an 178 in. sq. by 1/2 in. long gage section, were cut from 1/8 in. thick sheet of cold rolled and annealed (8 hr at 1000oF) material. The latter specimens were supported in a special jig during the milling operations to avoid any bending, and the gage section was subsequently heavily electropolished to remove the cold-worked surface layer. The bicrystals (ID) were machined in the same

Jan 1, 1963

By E. T. Turkdogan, J. H. Swisher

The solubility of oxygen in zone-refined iron was determined in the temperature range.from 881" to 1350°C. The solubility in a iron at 881°C ms found to be about 2 to 3 ppm; in y iron, the solubility was found to increase from about 2 to 3 ppm at 950°C to about 25 ppm at 1350°C. The permeability of oxygen in an iron -0.1 pct Al alloy was determined in the y iron range, using an internal oxidation technique. By combining the permeability and solubility data, the diffzisivity of oxygen in y and a iron was calculated. The oxygen diffusivity in solid iron may be s~immarized as follows: 8820 For 6 iron and IN a recent paper, Hepworth, Smith, and Turkdogan1 reported on the solubility, permeability, and diffusivity of oxygen in 6 iron, together with permeability data for oxygen in a iron. In the present investigation, similar measurements were made in the ? phase region. In addition, a solubility measurement was performed in the a phase region to permit calculation of the diffusivity of oxygen in a, iron. References to early work on this subject are given in the previous publication.' EXPERIMENTAL Solubility Measurements. The oxygen solubility was determined by equilibrating cylindrical samples 0.3 in. diam by 14 in. long of zone-refined iron in water vapor-hydrogen gas mixtures. The zone-refined iron was prepared by B. F. Oliver of this laboratory, using an apparatus and technique described elsewhere.2'3 Six zone-melting passes were used to achieve a total impurity level of about 30 ppm. Of this 30 ppm, the combined nickel and cobalt content was about 20 ppm, oxygen was 4 ppm, and all oxidizable impurities less than 1 pprn each. A vertical resistance furnace wound with molybdenum wire was used for the experiments. The temperature was measured before and after each experiment with a Pt/Pt-10 pct Rh thermocouple. In the gas train, flow rates of hydrogen and argon were measured with capillary flow meters, and the resulting mixtures were passed through a column containing 90 pct oxalic acid dihydrate and 10 pct anhydrous oxalic acid to obtain predetermined ratios of H2O to H2. The vapor pressure of H2O above this mixture as a function of temperature is well-known.4 The exit gas was ana- lyzed periodically for H2O, and good agreement (+3 pct) with the calculated composition was obtained. The zone-refined iron specimens were held in the furnace for a sufficient length of time for equilibration, e.g., 18 hr at 1350°C and 1 week at 881°C, then quenched in a brine solution. After removing the surface oxide from the samples by machining, duplicate analyses were obtained by a combined vacuum fusion-infrared method; oxygen analysis was reproducible within 2 ppm. Permeability Measurements. The permeability of oxygen in alloys containing about 0.1 pct A1 was determined by internal oxidation and measurement of the subscale thickness as a function of time. The experimental alloys were prepared by adding aluminum to electrolytic iron (grade 104A plastiron) that had previously been vacuum-carbon deoxidized. The resulting ingots contained about 20 ppm O, 100 pprn C, 40 pprn Si, 50 ppm Mo, 20 ppm P, 20 ppm S, and 20 pprn Zr as the principal impurities. After hot rolling the ingots to 1-in.-thick slabs, specimens were machined from the stock in the form of rectangular plates, 4 by 5 by 2 in. The general procedure for the permeability experiments was the same as those for the solubility measurements. The specimens were cooled in a reducing atmosphere rather than quenched, however, in order to maintain a clean surface for measurement of the sub-scale thickness. This measurement was made on a polished cross section of each specimen, using a microscope with a micrometer stage. The inclusions formed at the lowest temperature 1033°C were too small to be seen with an optical microscope. An electron micrograph showing the size and shape of individual particles is shown in Fig. 1. The dark band in the picture is a boundary between two subgrains. The subscale thickness in these samples was measured with an optical microscope after heavily etching in 2 pct nital, which gave contrast between the subscale and the unoxidized zone.

Jan 1, 1968

By William L. Saunders

MANY members of the Institute, who participated in the visit made, during the Bethlehem meeting of February, 1906, to the shops of the Ingersoll-Rand Company, at Phillipsburg, N. J., inspected with interest the new Electric-Air drill, which the company had set up for the purpose of showing it in actual operation to American. mining engineers. At the request of the Secretary of the Institute, I promised at that time to prepare a paper for our Transactions, describing the construction and advantages of the machine. But such a paper would then necessarily have contained much that was only expected or claimed by the designers and manufacturers of the drill, and not yet incontrovertibly proved by varied and long-continued practice. However moderate such statements might have been, they would have given inevitably to the paper, to some extent at least, the air of a prospectus, rather than of a technical contribution. I therefore decided, with the Secretary's approval, to postpone the writing of the promised paper until it could set forth the results of adequate actual practice, as well as the latest details of construction, etc., based upon practical experience. That period has now arrived. The Electric-Air drill has been exhaustively tested in the field, under varied and arduous conditions and upon the hardest rocks. It is now fairly in the field; its merits and performances are matters of unimpeachable record, and its place among established competitors can be definitely determined. As a representative of the Ingersoll-Rand Co., as well as a member of the Institute, I may be permitted to add that my company, being largely interested in the manufacture of air-

Jan 9, 1907

By Edward Sampson, Allan B. Griggs

Surveying of many holes drilled by the U. S. Bureau of Mines in the Metaline district has shown surprising deviations. The holes start in the Ledbetter slate (Ordovician) and pass into the underlying gently dipping Metaline limestone (Cambrian) at varying depths, locally in excess of 1000 it. All holes start vertical, but one had deflected as much as 35° at a depth of only 300 it. One hole was found to be deflected 70' at a depth of 1000 ft. These deviations were not indicated to the drillers by any action of the rods or machines. Analysis of the survey data in the light of the observed geology indicates that the holes deviate most in the Ledbetter slate and scarcely at all in the Metaline limestone. The upper part of the "limestone'" in most holes is a massive rock strongly altered by hydrothermal action and essentially homogeneous. The slate is only obscurely bedded but has a cleavage, varying from slight to strong, which is unrelated to bedding. Drill holes have deflected to become nearly perpendicular to the cleavage. Several plans and cross sections are submitted showing the behavior of various holes. Introduction The Metaline district of northeastern Washington has received much attention recently and has promise of becoming even more important as a source of zinc than at present. Exploration has been conducted largely by deep diamond drilling, and in the course of this work it was found that holes became seriously deflected. This paper deals with the nature and causes of these deflections. The district lies along the Pend Oreille River in the northeastern corner of Washington, about loo miles north of Spokane, 9 miles from British Columbia, and 15 miles from Idaho. Three mines are now in operation and for a number of years have furnished a considerable production of zinc and lead. The ore contains zinc and lead in a ratio of about 31/2 to I, and occurs in the upper part of the Metaline limestone of Cambrian age, the upper member of which, where unaltered, is a rather pure limestone. This is overlain by Ledbetter slate of Ordovician age. Ore has formed by replacement of limestone, commonly 100 to 200 ft. below the slate, in areas of gentle dip, resulting in extensive tabular ore bodies. In and near ore, limestone has been intensely altered to granular dolomite and fine-grained quartz, which, where it predominates, forms "jasperoid." As part of their war program, the Geological survey and Bureau of Mines of the U. S. Department of Interior have been cooperating in an investigation of the district. The exploration by the Bureau of Mines in 1943 and 1944 was conducted largely by deep diamond drilling in which as much as 1000 ft. or more of Ledbetter slate was penetrated before the ore-bearing Metalin-2 limestone was reached. During the course of this drilling it was found that holes were seriously deflected while traversing the Ledbetter slate.

Jan 1, 1949