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By F. Weinberg, E. H. McLaren

Dilute binary alloys have been solidified under controlled thermal conditions, and solute distributions, temperatures during freezing and melting, and the position and morphology of the solid-liquid interfaces have been examined. Binary Zn, Sn, and Pb based alloys were investigated with solute additions of AgU°, AU°, Sb'24, TlZo4, snH3, and Zns5. Approximately 150 cc of metal was used in each ingot. Appreciable solute segregation occurred in most of the ingots, depending on the solute concentrations, distribution coefficients. and freezing conditions of the alloys. Measurements were made of the general solute distribution by sectioning layers of material from the ingot circumference and counting the activity of each layer. Local segregation was detected by autoradiographic techniques. Freezing and melting curves for the same alloys were obtained by precision resistance thermometry. These curves are related to the corresponding measured solute distribution curves and those calculated from theoretical expressions. The position and morphology of solid-liquid interfaces during freezing were determined by both decanting and quenching techniques. The results indicate the manner in which freezing and remelting occurred under the conditions investigated. If an isomorphous dilute binary alloy is solidified or melted under equilibrium conditions, the concentration of solute in both solid and liquid would be uniform at all stages in the freezing process. The solute concentrations during freezing could be determined from the phase diagram of the alloy, and the freezing curves would have an alloy slope defined by the solidus and liquidus points. In practice, however, solidification under equilibrium conditions rarely, if ever, occurs, primarily because of low rates of diffusion in the solid and incomplete mixing in the liquid. As a result, the solute distribution and the shape of the freezing and melting curves obtained in a given system depends on a number of factors. These include, in addition to the extent of diffusion and mixing, the initial solute distribution and concentration, the distribution coefficient, the rate of freezing or melting, supercooling of the liquid, the morphology of the solid-liquid interface, and the effect of annealing. The purpose of the present investigation was to determine, experimentally, actual solute distributions and thermal curves for a series of dilute binary alloys, using tracer techniques to determine the solute distributions and precision resistance thermometry for the temperature measurements. In addition, observations were made of the positions and morphologies of the solid-liquid interfaces during freezing and remelting. The distribution of solute in a dilute alloy, assuming complete mixing in the liquid, and negligible diffusion in the solid, is given by1 where Co is the mean solute concentration of the alloy, C, is the solute concentration in the solidg is the fraction of the ingot solidified, and ko is the equilibrium solute distribution coefficient (assumed to be independent of concentration for dilute alloys). For the case of partial mixing, ko can be replaced by an effective distribution coefficient k. If solute transport in the liquid is assumed to be entirely due to diffusion, with negligible diffusion in the solid, then the solute distribution in the solid is given by Tiller et a1.' as where R is the rate of advance of the solid-liquid interface, D is the solute diffusion coefficient in the liquid, and x is the position of the interface from the start of freezing. The temperature at the interface TI is related to the solute concentration of the solid at the interface C, by the expression where Tm is the freezing temperature of the pure solvent and ml is the slope of the liquidus for the binary alloy being considered. Accordingly, by relating TL to the actual temperatures measured in the present experiments, solute distributions can be deduced from the temperature measurements. Using the above expressions, the measured solute distribution of a given alloy may be compared to the theoretical distributions, as well as to the distribution calculated from the observed freezing curve. EXPERIMENTAL The solvent materials used in making up the binary alloys were C. P. New Jersey zinc (99.999 pct), Vulcan Extra Pure Tin (99.999 pet), and Tadanac lead (99.998 pct). The solute elements were of 99.99 pct purity or better, and were activated in the

Jan 1, 1963

By Howard N. Eavenson

FROM the Pittsburgh coal bed in the four states of Pennsylvania, Ohio, Maryland and West Virginia has been produced an output that, at mine prices, represents a greater value than any other single mineral deposit in the world has yielded.12 While this distinction may in a few years pass to the gold reef of the Witwatersrand, it is possible that eventually, owing to the tremendous reserves still remaining, the ultimate yield of the Pittsburgh bed will be greater than that of any other known single deposit. Considering its importance, not a great deal has been written of its early history and development as a whole; most of the accounts have been of limited localities, or, at the most, of the area within a single state. In "Coal through the Ages" the writer mentioned some references to its early history, but this study will deal not only with its history but with the character of the bed, where and why it was first developed, and its effect upon the states in which it is found. It has not been the intention to write a detailed history of the development of the seam in each locality, as neither time nor inclination were available for doing such work, but only to show the influences that tended to hasten or retard such development. In general the historical matter ends about 1830, when geological surveys began to be made. Some of the maps show data available only since that time, and the sections about coal preparation and coking have been extended to the present time to show the changing conditions. It is believed that the early history includes all published records, and many more sources than those shown in the bibliography were consulted. It is quite likely that some references to coal in this area may be found in the unpublished papers of some of our early soldiers and colonizers, which exist in several libraries, and it is hoped that some future

Jan 1, 1938

By William Emmons

THE problem of the metalliferous veins has always been an outstanding one in the science of ore deposits. In recent years interest has been stimulated by Spurr, who maintains that veins have consolidated from magmas that have densities as great as the densities of ordinary rocks. Lindgren published a noteworthy paper1 in 1926, in which he supports the theory that veins are deposited chiefly by hot waters. Lindgren's paper was discussed by Singewald, Spurr, Kemp, Anderson, Colony, Bateman, Porter and others. The discussion, in the main, was centered on the interpretation of fragments that are included in veins. This paper also treats the problems of fragments in veins and includes a reply to a review by Spurr2 of a bulletin by Larsen, and myself published by the United States Geological Survey on the geology and ore deposits of Creede, Colorado. Mineral veins containing fragments of the wall rock are common. At many places the fragments are completely, isolated, one from the other, and are entirely surrounded by vein matter. It has been stated that the vein matter around the fragments was heavier than the fragments and that the latter were floated in a magma. J. E. Spurr, who is the leading advocate of this hypothesis,4 urges that normal mineral veins were deposited by solutions heavy enough to float fragments of the country rock, and it is mainly on this relation that he bases his theory that veins are deposited by solidification of magmas. If it can be shown that vein-forming solutions have a specific gravity greater than rock (2.77), one is justified in regarding them as true magmatic solutions. It is shown later in this, paper,. however, that at Lead, S. D., water not more highly concentrated' than ordinary drinking water is depositing vein matter around fragments of schist and of steel in such a manner that the fragments are completely isolated and completely surrounded by the mineral cement.

Jan 1, 1928

By Rollin E. Hook, Attwell M. Adair

The yield and fracture behavior of recrystallized chromiztm have been studied in order to gain an understanding of the recrystallization embrittlement-rheotropic recovery phenomenon. The duc tile-brittle tensile transition temperature of recrystallized chromium was found to vary from 225 ° to -80°C as the ratio of specimen diameter/mean planar grain size decreased. The applicability of this observation to other bcc metals is briefly discussed. Brittle fracture in recrystallized chromium was found to be initiated predominately from intercrystalline rupture nuclei. Single crystals exhibit a high degree of ductility at 23 "C. The experimental data indicate that grain boundaries play a significant part in the yield and fracture behavim. Pres training significantly reduces the transition temperature, and high temperature aging does not result in re-embrittle-ment until complete recovery or re crystallization occurs. SEVERAL theories have been used to explain the recrystallization embrittlement-rheotropic recovery phenomenon in chromium. Wain, Henderson, and ohnstone' propose a Cottrell dislocation locking mechanism due to nitrogen, and Weaver and Gross and weaver 3 propose a strain-induced precipitation mechanism involving a chromium nitride precipitate. The researches of many investigators seem to leave little doubt that brittleness in chromium is promoted by interstitial impurities. Smith and seybolt4 have shown that the ductile-brittle transition temperature is lowered as the interstitial content is reduced. weaver3 provides evidence for a 150°C reduction in the tensile transition temperature as the nitrogen content is reduced from 20 to 5 ppm. Maykuth and affee' have suggested that the amount and orientation of grain boundary impurities may be responsible for the brittle nature of recrystallized chromium. This suggestion was based on their findings that wrought iodide chromium possessing a fiberous grain structure is ductile in tension at room temperature while a recrystallized grain structure is completely brittle. Previous investigations have not studied this phenomenon sufficiently to determine its cause. Perhaps this has been largely due to previous experimental findings that brittle fracture observed in chromium has been almost entirely transgranular.' In addition McNeil and imb,' who investigated coarse-grained as-cast chromium, describe the point of initiation of fracture as cleavage, close to the (100) plane, near or at grain bound-daries, or at included particles or voids. However, Hook, Adair, and ipsitt found that fracture in coarse-grained recrystallized chromium is initiated by intergranular rupture and then propagates nearly entirely by cleavage. This result, together with their finding that room temperature ductility in bending is observed for single crystals and coarse-grained polycrystalline specimens for which the number of grains through the specimen diameter is small, suggests that grain boundaries may play an important role in the brittle behavior of chromium. The recrystallization embrittlement problem can be resolved into two questions. These are, whether the controlling mechanism is predominately one of crack initiation or crack propagation, and whether brittle fracture is initiated predominately by slip or twin induced intergranular rupture or by cleavage. The following research was designed to study the role of grain boundaries on the brittle fracture of chromium in an effort to resolve these questions. EXPERIMENTAL PROCEDURES, RESULTS, AND DISCUSSION General Procedure. All tensile specimens (except 0.04 in. diam wires) were prepared from 1/4 in. diam swaged rod fabricated from one ingot. Details of fabrication are given elewhere. The results of impurity analysis for the swaged rod and for the

Jan 1, 1963

By A. H. Geisler, R. F. Mehl, S. Barrett

The studies of the mechanism of pre= cipitation and of the resulting property changes in aluminum-silver alloysl-3 have presented some new concepts of the aging reactioxl—concepts that may be fundamental in establishing a complete quantitative theory of age-hardening. With both aluminum-copper and aluminum-silver alloys, thin platelike aggregates form parallel to the Widmanstätten planes of precipitation.l,4 These platelets grow in lateral dimensions and in thickness with aging time until they arc thick enough to produce an X-ray diffraction line pattern. Their structure is that of a transition lattice which is coherent with the matrix, since the atomic spacings in the matrix and the precipitate are the same on each side of their common interface.2,4 The equilibrium precipitate forms later from and at the expense of the transition lattice. Since age-hardening occurs during the formation and growth of the transition lattice, the major contributor to the hardening no doubt is the stress condition in the matrix resulting from the matrix holding the precipitate in the coherent condition. The development of these stresses also appears to be responsible for an increase in the electrical resistance superimposed on the normal decrease resulting from a change in the concentration of the matrix during aging.3 The two consecutive reactions constituting the aging process are accompanied by characteristic microstructural alterations. The initial precipitation process results in the formation of a Widmanstatten figure, while the later transformation of the transition lattice to the equilibrium lattice is accompanied by a coalescence, in the case of aluminum-copper alloys,5 and by the appearance of light areas at the grain boundaries with aluminum-silver alloys showing a structural rearrangement of matrix and precipitate.3 This latter reaction is similar microscopically to the so-called "discontinuoils precipitation." Possibly discontinuous precipitation is a process that often if not always follows true precipitation of a coherent lattice and during which the transformation of the coherent transition lattice to the equilibrium lattice takes place accompanied by matrix recrystallization.3 Expermental Procedure The alloys were made using 99.97 per cent A1 or distilled magnesium, with

Jan 1, 1943

By R. F. Mehl, A. H. Geisler, S. Barrett

The studies of the mechanism of pre= cipitation and of the resulting property changes in aluminum-silver alloysl-3 have presented some new concepts of the aging reactioxl—concepts that may be fundamental in establishing a complete quantitative theory of age-hardening. With both aluminum-copper and aluminum-silver alloys, thin platelike aggregates form parallel to the Widmanstätten planes of precipitation.l,4 These platelets grow in lateral dimensions and in thickness with aging time until they arc thick enough to produce an X-ray diffraction line pattern. Their structure is that of a transition lattice which is coherent with the matrix, since the atomic spacings in the matrix and the precipitate are the same on each side of their common interface.2,4 The equilibrium precipitate forms later from and at the expense of the transition lattice. Since age-hardening occurs during the formation and growth of the transition lattice, the major contributor to the hardening no doubt is the stress condition in the matrix resulting from the matrix holding the precipitate in the coherent condition. The development of these stresses also appears to be responsible for an increase in the electrical resistance superimposed on the normal decrease resulting from a change in the concentration of the matrix during aging.3 The two consecutive reactions constituting the aging process are accompanied by characteristic microstructural alterations. The initial precipitation process results in the formation of a Widmanstatten figure, while the later transformation of the transition lattice to the equilibrium lattice is accompanied by a coalescence, in the case of aluminum-copper alloys,5 and by the appearance of light areas at the grain boundaries with aluminum-silver alloys showing a structural rearrangement of matrix and precipitate.3 This latter reaction is similar microscopically to the so-called "discontinuoils precipitation." Possibly discontinuous precipitation is a process that often if not always follows true precipitation of a coherent lattice and during which the transformation of the coherent transition lattice to the equilibrium lattice takes place accompanied by matrix recrystallization.3 Expermental Procedure The alloys were made using 99.97 per cent A1 or distilled magnesium, with

Jan 1, 1943

By Alfred H. Bell, Virginia Kline

In 1944, Illinois produced 77,413,000 bbl. of oil, or 4.6 per cent of the total for the United States, and continued to rank sixth in the nation in oil production. This represents a decrease of 6 per cent from 1943, when- the total Illinois production was 82,256,000 bbl. This decrease was much less than the 23 per cent decrease in 1943 from production of the previous year. The principal factor in arresting the production declinc, which had been going on since 1941, seems to be the increased drilling that followed the relaxing of the Federal Government's rules in regard to well spacing. The daily average production for 1944 was approximately 212,000 bbl. Daily averages by months were as follows: Jan......... 219,000 July........ 206,000 Feb......... 220,000 Aug......... 211,000 Mar........ 216,000 Sept......... 209,000 Apr......... 211,000 Oct......... 210,000 May........ 213,000 Nov........ 209,000 June........ 209,000 Dec......... 205,000 During the year, 1991 wells were drilled for oil and gas in Illinois as compared with 1791 in 1943, an increase of II per cent. Of the 1991 wells, 430 are classified as "wildcat" as compared with 461 in 1943. Twenty-eight new pools (Table 2 A) were discovered in 1944 as compared with 29 in 1943. Changes in federal drilling regulations, permitting closer spacing of wells, resulted in a drilling program that emphasized development of proved acreage rather than wildcatting. Data on production and drilling by fields are given in Table I; data on annual production and drilling for Illinois, in Table 3. Discoveries Twenty-eight new fields (Table 2 A), 42 extensions (Table 2 B), and 39 additional producing zones in existing fields (Table 2 C) were discovered in 16 counties in Illinois during 1944. Of the 28 new fields, one was abandoned during the year, 14 were one-well fields, eight others had not more than 6 wells, one had 8, one had 9, one had 11, one had 15, and the largest new field, Roaches North, had 28 producing wells at the end of the year. In all, 109 wells were producing in these new fields on Jan. 2, 1945, as compared with 111 wells producing from 29 new fields at the end of 1943. . The average initial production of the discovery wells of the 28 new fields was 129 bbl. of oil and II bbl. of water, a notable decline from the average initial production of 194 bbl, of oil and 15 bbl. of salt water for the 1943 discovery wells. In fields discovered since 1936, the total number of oil wells producing at the end of 1944 was 12,335. Productive Acreage The area of proved production in the new fields (discovered since 1936) increased from 144,335 acres at the end of 1943 to 173,485 acres at the end of 1944 (Table I), an increase of 29,150 acres. Of this increased area, 1720 acres are in fields discovered during 1944 and 27,430 acres are in extensions of fields discovered earlier.

Jan 1, 1945

By G. C. Broadhead

The lead district of Southeast Missouri covers an area of over 3000 square miles, including Maries County on the west, Jefferson on the east, Franklin on the north, and part of Madison on the south, or parts of ten counties. A general section of the rocks of the southeast part of this region would be about as follows, numbering from the top: 1. Sandstone (the second of Missouri geologists),.... 20 feet. 2. Chert beds—beds of passage below,...... 126 " 3. Magnesian limestone, chert, and quartzite,. .. 100 to 300 " 4. Lower magnesian limestone,......100 to 150 " 5. Gritstone and lingula beds,....... 50 " 6. Ozark marble beds,........5 to 20 " 7. Sandstone and conglomerate,. .. .. 5 to 90 " 8. Porphyry, Archæan 9. Granite, The thickness is approximate, for it is not possible to obtain the correct thickness of the various beds. No. 1 may be seen as detached outliers or loose masses of a hard sandstone or quartzite, and is found on the hilltops in the southern part of Madison County, in like topographical position in Reynolds County and the western part of Washington County. No. 2 consists of alternations of chert, clay, and quartzite. It is the formation which contains most of the limonite deposits of Central and Southern Missouri. In Reynolds County shafts have penetrated it 75 feet. Outcrops there and in Madison would indicate it to be at least 125 feet thick. Fossils obtained in various places prove it clearly to be of the age of the calciferous saudrock of the New York system, and Nos. 1 and 2 may also be referred to the age of the second sandstone of Missouri. No. 3 consists chiefly of thick beds of ash, drab and flesh-colored magnesian limestone, both coarse and fine-grained. These beds, where they occur, in Washington, Jefferson, and the southern part of Madison Counties, contain a good deal of quartz in drusy cavities. In Washington County the limestones are beautifully ramified by a system of connected drusy cavities generally lined with minute quartz crystals arranged in botryoidal and mammillary forms, and called " mineral blossom " by the miners. This is the lead-bearing rock of Washington County, but in the southern part of Madison it does not appear to be galeniferous. It is also undoubtedly the equivalent of

By W. M. Rust, W. D, D. W. Mounce

The almost universal acceptance of electrical logging by the petroleum industry calls for a critical examination of the physical bases of the common methods. This is particularly needed for the natural potential log. The conventional explanations are based on the phenomena of electrofiltration and electro-osmosis. However, experimental data show that they fail to give a basis that is quantitatively sound. Moreover, they lead to interpretations of details of electrical logs that are erroneous. It was found experimentally that when a plug of shale is placed in a chain of dissimilar electrolytes, a current flow results. Experiments on oil-well cores and fluids similar to those existing in wells show that potentials are set up which are in reasonable agreement with those encountered in electrical logging. Doubtless other sources of potential are important but this explanation not only accounts for much of the potential but also clarifies some fairly familiar examples of misinterpretations. Introduction The extraordinary value of electrical well logging as a tool for petroleum engineers and geologists is now so uni- versally recognized that it is not necessary to point out the ways in which it can be useful. It is sufficient to mention only the saving that has resulted from the elimination of much coring that would have been necessary under former practices and the considerable additions to reserves resulting from the discovery of sands missed in coring. Paradoxically, the very remarkable success that has resulted from the application of electrical logging to correlation and completion problems has cost some of its most consistent users dearly.' The fact that some operators have placed unwarranted faith in erroneous interpretations of electrical logs does not reduce the value of the logs. It should, however, make one pause long enough to ask why experienced users should be misled. The answer to this question is not hard to find. In nearly every case, the fault has been oversimplification. This is illustrated very aptly by the familiar interpretation and theory of the natural potential log. Recording and Interpreting Logs The natural potential log is extremely simple to record precisely enough for all present-day uses. One needs only an electrode, a cable to lower the electrode through the drilling mud, a recording meter and a surface ground connection. The electrode can be elaborate but need not be. A simple brass rod 2 in, in diameter and 2 or 3 in. long is quite satisfactory. The cable need not be particularly well insulated, nor need it have a very low resistance. The recorder can be a vacuum-tube 1 References are at the end of the paper.

Jan 1, 1944

By W. D, D. W. Mounce, W. M. Rust

The almost universal acceptance of electrical logging by the petroleum industry calls for a critical examination of the physical bases of the common methods. This is particularly needed for the natural potential log. The conventional explanations are based on the phenomena of electrofiltration and electro-osmosis. However, experimental data show that they fail to give a basis that is quantitatively sound. Moreover, they lead to interpretations of details of electrical logs that are erroneous. It was found experimentally that when a plug of shale is placed in a chain of dissimilar electrolytes, a current flow results. Experiments on oil-well cores and fluids similar to those existing in wells show that potentials are set up which are in reasonable agreement with those encountered in electrical logging. Doubtless other sources of potential are important but this explanation not only accounts for much of the potential but also clarifies some fairly familiar examples of misinterpretations. Introduction The extraordinary value of electrical well logging as a tool for petroleum engineers and geologists is now so uni- versally recognized that it is not necessary to point out the ways in which it can be useful. It is sufficient to mention only the saving that has resulted from the elimination of much coring that would have been necessary under former practices and the considerable additions to reserves resulting from the discovery of sands missed in coring. Paradoxically, the very remarkable success that has resulted from the application of electrical logging to correlation and completion problems has cost some of its most consistent users dearly.' The fact that some operators have placed unwarranted faith in erroneous interpretations of electrical logs does not reduce the value of the logs. It should, however, make one pause long enough to ask why experienced users should be misled. The answer to this question is not hard to find. In nearly every case, the fault has been oversimplification. This is illustrated very aptly by the familiar interpretation and theory of the natural potential log. Recording and Interpreting Logs The natural potential log is extremely simple to record precisely enough for all present-day uses. One needs only an electrode, a cable to lower the electrode through the drilling mud, a recording meter and a surface ground connection. The electrode can be elaborate but need not be. A simple brass rod 2 in, in diameter and 2 or 3 in. long is quite satisfactory. The cable need not be particularly well insulated, nor need it have a very low resistance. The recorder can be a vacuum-tube 1 References are at the end of the paper.

Jan 1, 1944

By Alfred R. Powell

FOR the purposes of this discussion, the direct gasification of coal means the of hydrogen and carbon monoxide by the well-known water-gas reaction. Chemicals or other synthetic products may be made from these constituents of the gas and under such circumstances the gas is called synthesis gas. Or, if the same gas is used as a fuel, it is called blue gas or water gas. This type of gas has usually been made from coke, especially in this country, and has been used both for fuel purposes and for manufacture of chemicals. Recently, natural gas has gained the ascendancy as a source of synthesis gas for manufacture of chemicals because of its relative cheapness. As natural gas becomes less readily available and more expensive, coal will take its place as a raw material for the preparation of synthesis gas. This substitution will probably take the form of direct gasification of the coal rather than the present two-step procedure of carbonization of the coal followed by gasification of the coke. The chief reason for this probability is the intensive research now being carried on by several organizations to develop successful and economical processes for the direct gasification of coal, which is a considerably cheaper fuel than coke. In the following pages an attempt has been made to predict the chemicals that will result from this future production of synthesis gas by the direct gasification of coal. CHEMICAL REACTIONS OF SYNTHESIS GAS Given the proper conditions, there are many chemical reactions leading to production of useful products that can be carried out with this mixture of hydrogen and carbon monoxide. These many reactions may be grouped into three classes: (1) interaction of hydrogen and carbon monoxide, possibly with addition of other reactants; (2) reaction of hydrogen with various substances; (3) reaction of carbon monoxide with various substances. Thus sometimes hydrogen and carbon monoxide are utilized together in the same chemical reaction while in other instances only the hydrogen or only the carbon monoxide is required as a reactant. Fortunately, practical methods are available for securing either hydrogen or carbon monoxide from synthesis gas, some of which are also applicable for changing the ratio of these two constituents in the gas when that is desirable.

Jan 1, 1953

By C. M. Young

The following paper has been prepared with the object of placing on record in the Transactions some facts concerning the present condition and future prospects of the coal industry of Illinois. In presenting it, the writer wishes to say that a considerable amount of the material contained is taken from the publications and records of the Illinois Coal Mining Investigations, the annual Coal Report of the State Mining Board, and the work of the State Geological Survey. Coal Beds and Mining Methods According to the latest maps of the State Geological Survey, there are only 19 of the 102 counties of the State some portion of whose territory is not within the borders of the coal measures. If outlying areas in Calhoun and Whiteside Counties are considered, the number is reduced to 17. This does not mean that all of the 85 counties that are partly or wholly underlain by coal measures will become producers, as there are some portions of the State in which the coal does not occur in beds of such thickness as to warrant the hope that it can be mined. The mining of coal is widespread, however, for in 1916 there was production from 61 of the 102 counties of the State, There seem to be no cases in which operations will be limited by depth, as none of the coal measures lie at depths much greater than those at which it has been proved that coal may be profitably mined in this field. In fact, the deepest shaft reaching a bed of bituminous coal in the United States is located in this State at Assumption, where coal only 3 ½ ft. (1.07 m.) thick is worked at a depth of 1004 ft. (306 m.). The coal beds occur in the form of a basin which is deepest along a line extending through the central part of the State and bearing a little west of north. The northern, western and southern borders of this basin lie within the boundaries of the State, but on the eastern side the Illinois field is continuous with the Indiana field. The glacial drift covers all except the extreme southern end of the State and the visible outcropping

Jan 1, 1918

By Donald R. Mason, Daniel F. O’Kane

DIFFERENTIAL thermal analysis measurements have been used to determine the ZnTe-In2Te3 pseudo-binary phase diagram. Since ZnTe and In2Te3 are both semiconductors, any intermediate compounds formed in this system should also be semiconductors according to the rules delineated by Mooser and pearson.1 The compound ZnIn2Te4 was first reported by Hahn et a1.2 and it has subsequently been prepared and characterized electrically by several workers. A brief summary of this work has been presented by Mason and O'Kane3 who also report that the compound appeared to melt peritec-tically. The Zn-Te phase diagram has been investigated by Kulwicki4 who found that ZnTe has a melting point of 1290° + 2°C. The In-Te diagram published in Hansen' contains significant errors, and has been redetermined by Grochowski et al.6 However, both sources agree that the melting point of In2Te3 is 667°C, with the latter authors reporting the previously observed solid-solid transformation occurring at about 550°C. Hahn ef al.2 reported lattice-parameter values for the ZnTe-In2Te3 system. The 67 mole pct ZnTe-33 mole pct In2Te3 composition was the only

Jan 1, 1965

By S. Chander

A review of the published literature on the mechanism of depression of sulfide minerals shows that a unified theory is not yet available. Various mechanisms that have been postulated include competition between depressants and collectors to adsorb at the surface sites, creation of thermodynamic conditions nonconducive for formation of a metal collector salt, or formation of a hydrophilic coating on the surface. The hydrophilic coating may or may not effect the adsorption of collectors. In another mechanism, the depressant may participate directly in oxidation/reduction reactions between collectors and sulfide minerals. Examples from the literature highlight oxidation/reduction effects in the depression of sulfide minerals.

Jan 1, 1986

By Fred C. Bond

DISCUSSION Milton C. Shaw and Donald R. Walker (Massachusetts Institute of Technology)—For many years the two empirical rules of comminution bearing the names of Rittinger and Kick have been applied to grinding processes to account for the energy required to crush brittle materials. The basis for Rittinger's rule was the thought that the energy to grind a substance went largely into supplying the additional energy associated with the new free surface, while Kick's law was prompted by the concept of dimensional similarity and is a special statement of the concept of constancy of strain energy to cause rupture. According to Rittinger the energy to grind a given volume varies as the change in the square of the mean particle size, v - A (D2), while according to Kick this energy varies

Jan 1, 1953

By Fred C. Bond

DISCUSSION Milton C. Shaw and Donald R. Walker (Massachusetts Institute of Technology)—For many years the two empirical rules of comminution bearing the names of Rittinger and Kick have been applied to grinding processes to account for the energy required to crush brittle materials. The basis for Rittinger's rule was the thought that the energy to grind a substance went largely into supplying the additional energy associated with the new free surface, while Kick's law was prompted by the concept of dimensional similarity and is a special statement of the concept of constancy of strain energy to cause rupture. According to Rittinger the energy to grind a given volume varies as the change in the square of the mean particle size, v - A (D2), while according to Kick this energy varies

Jan 1, 1953

By C. E. Shoenfelt

There was very little oil activity in Utah in 1938. A few wildcat tests were drilled and the well at Cane Creek, started in 1937, was in active operation, but failed to reach its objective by the close of the year. The Clay Basin field in Daggett County, northeastern Utah, was extended about a mile east by the Mountain Fuel Supply Co. with the completion early in June of No. 3-D Murphy, NW. NW. SW. of sec. 23-3N-24 E. This well had an initial production of 16,000,000 Cu. ft. of gas a day under 2160 Ib. pressure, from Dakota sand at 5918 to 5925 ft. after plugging back from a total depth of 6035 feet. The Clay Basin field, in the few years it has been in operation, has developed into a gas field of major importance. Approximately 1300 acres has now been proved by development. Six wells are on production, five of which were completed in Dakota sand and the sixth in a sand in the Frontier formation. The field was connected to the Salt Lake line

Jan 1, 1939

By C. E. Shoenfelt

There was very little oil activity in Utah in 1938. A few wildcat tests were drilled and the well at Cane Creek, started in 1937, was in active operation, but failed to reach its objective by the close of the year. The Clay Basin field in Daggett County, northeastern Utah, was extended about a mile east by the Mountain Fuel Supply Co. with the completion early in June of No. 3-D Murphy, NW. NW. SW. of sec. 23-3N-24 E. This well had an initial production of 16,000,000 Cu. ft. of gas a day under 2160 Ib. pressure, from Dakota sand at 5918 to 5925 ft. after plugging back from a total depth of 6035 feet. The Clay Basin field, in the few years it has been in operation, has developed into a gas field of major importance. Approximately 1300 acres has now been proved by development. Six wells are on production, five of which were completed in Dakota sand and the sixth in a sand in the Frontier formation. The field was connected to the Salt Lake line

Jan 1, 1939

By G. G. Gunther, C. L. Boeke

THE zinc deleading processes at the Parral and Santa Barbara mills are described separately to provide a basis for comparison. Although the two procedures are fundamentally alike, there are some differences in application to meet specific conditions. The Asarco mill at Parral in the State of Chihuahua is a flotation plant treating 1450 metric tons- per day of complex sulphide copper-lead-zinc ores. In general, the procedure used for selective separation of the minerals into a copper, a lead, and a zinc concentrate follows the usual practice. First, a bulk copper-lead concentrate is floated and then separated into a final copper and a final lead concentrate by the sulphurous acid process. A small tonnage of high grade gravity lead concentrate is tabled from the bulk copper-lead cleaner tailing before it is reground so as to avoid undesirable over-grinding and sliming of this portion of the lead, mineral. Next, a zinc concentrate is floated from the lead rougher tailing and, as described later, is separated into a final lead product and a final zinc concentrate. Finally, the zinc rougher tailing receives a strong scavenger float to remove all recoverable middling values for regrinding, and return to the flotation circuits. The slime is separated from the scavenger flotation product, and only the sand portion goes to the regrind section. The minerals in the separated slime are extremely resistant to all methods of selective separation and pose one of the major problems awaiting solution. Nevertheless, the slime shows a profit when mixed with either the lead or the zinc concentrate, except when metal prices are very low, so it is accepted as a final product for lack of a more profitable method of handling it. In contrast, the minerals in the reground sands of the

Jan 1, 1952

By Kittitep Fuenkajorn

Ring tension tests, permeability tests, and microscopic fracture studies have been performed to investigate the damaged zone induced by drilling (diamond, percussion, and rotary) in the borehole walls. Specimens are drilled with three different hole sizes (38, 76 and 102 mm diameter) in Pomona basalt and Grande basaltic andesite. The thickness of the damaged zone ranges from 0.0 to 1.7 mm. A larger drill bit induces more wall damage than a smaller one. Different drilling techniques show different damage characteristics (intensity and distribution). Damage characteristics are governed not only by drilling parameters (bit size, weight on bit, rotational speed, diamond radius, and energy), but also by properties of the rock. The weaker rock tends to show more intense damage than does the stronger one. Cracks within grains or cleavage fractures are predominant in coarse grained rock (larger than 0.5 mm grain size) while intergranular cracks are predominant in fine grained rock (smaller than 0.01 mm grain size). The influence of the damaged zone on the permeability of the rock around the hole is investigated by permeability tests.

Jan 1, 1984