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1-Coal and Coal Products HOWARD N EAVENSON, Chairman C. T. HAYDEN, Vice-chairman, Bituminous Coal Production CHARLES DORRANCE, Vice-chairman, Anthracite Coal Production HOWARD P. ZELLER, Vice-chairman, Evaluation of Coal for Coke Making W H. FULWEILER, Vice-chairman, Gas and Its Manufacture J. B. MORROW, Vice-chairman, Coal Preparation Bituminous Coal Production C. T. HAYDEN, Chairman R L ADAMS EUGENE MCAULIFFE HAROLD J ROSE WILLIAM H BLAUVELT H E NOLD D. A RUSSELL GEORGE W EVANS JAMES W PAUL CECIL W. SMITH JOHN A GARCIA GEORGE S RICE SAMUEL A TAYLOR H. S GEISMER W F RITTMAN F G TRYON FRANK HAAS J D ROGERS FRANCIS R WADLEIGH CHESTER M LINGLE

Jan 1, 1923

By William T. Schneider, Taylor Cole

Drilling in West Texas during 1941 was more active than in any year since 1937, a total of 2325 wells having been drilled. Pre-Permian exploration was the greatest in the history of the area; 106 wells tested pre-Permian formations during the year. Wildcatting reached the peak since 1937, with 135 wildcats, of which 20 per cent were producers. The wells were drilled to a greater average depth than in any previous year. Slim-hole drilling was the common practice, using drilling equipment that is largely portable. Because of deeper drilling, more attention was paid to mud fluids, especially the use of materials to reduce water filtration. There has been slight improvement in the protection of the pay horizons while drilling by the use of reverse circulation, and drilling-in with oil as well as low water-filtration muds. The practice of setting and cementing the oil strings through the producing formation and perforating opposite the pay zones has increased in the fields producing from sands. It is doubtful whether this practice is of unusual value in dolomitic limestone fields. There have been few if any technological improvements in obtaining necessary information on the pay sections penetrated, by coring, core analyses, better sampling, and more detailed drilling time. However, more operators are beginning to realize the necessity of good samples. For a proper study of the reservoirs in West Texas, it is essential that better samples be obtained, that more core analyses be run, and that better methods of obtaining drilling time be initiated. It should be noted that increased drilling speeds and slim-hole drilling have tended to reduce coring and core recovery and have not aided in obtaining good subsurface samples. In fact, fast drilling speeds and slim-hole drilling have reduced the cost of drilling operations, but with the sacrifice of much needed subsurface information. Larger quantities of slower-reacting acid are being used per well. There has been improvement in shooting, in that a greater number of quarts per foot have been used and an attempt has been made to concentrate the shots opposite the pay zone. The use of mud logging to determine the characteristics of the pay section increased considerably over the year 1940. There has been a slight increase in obtaining reservoir information in the new fields, such as bottom-hole sampling, bottom-hole pressures, and records of gas, oil, and water withdrawals. However, there is great need for more data on these subjects, particularly accurate information regarding gas and water volumes. There are three repressuring projects and a fourth is nearly ready for operation in the Kermit field. There is one repressur-ing project in the Payton field and one in the North Ward field. So far, the gas-injection projects have not shown very impressive results. As yet, there are no water-flooding projects or water-disposal projects in West Texas. Not including gathering lines within the fields, 222 miles of feeder pipe lines were

Jan 1, 1942

By J. R. Thoenen

The Bureau of Mines has used various sizes of core barrels above 2 in. and below 10 in. in diameter to core manganese, potash, coal, brown iron ore and bauxite. The paper describes in some detail the methods and types of equipment used to obtain maximum sampling accuracy. Introduction On December 11, 1946, R. D. Longyear, in his capacity as Chairman of the Subcommittee on Exploration Drilling, wrote the author requesting him to prepare a paper presenting the collective ideas of engineers in the Bureau of Mines on the design, standardization and application of core barrels using diamonds or other hard cutting media for drilling holes larger than two inches and less than ten inches in diameter. In subsequent correspondence it was indicated that similar papers covering the experience of other government agencies would be solicited and all such papers received would be combined in a symposium on the subject for discussion at the March 1947 meeting of the Mining Methods Committee AIME. In soliciting such information from other Bureau engineers, it developed that most Bureau experience had been confined to standard core size, two inches or less in diameter, and that larger sizes had been used only for special purposes. It is hoped the data contained herein will be of help to other operators in solving problems encountered in the field. Acknowledgments This paper was made possible by the request of Lowell B. Moon, Chief, Mining Division, Bureau of Mines, to all Division engineers to send to the author any data they had on the subject. Engineers of the Mining Division contributing were: M. H. Kline, Chief, Raleigh Branch. Paul T. Allsman, Chief, Salt Lake City Branch. J. H. Hedges, Chief, Tucson Branch. C. H. Johnson, Chief, Rolla Branch. A. M. Evans, Mining Engineer, College Park Branch. Wing Agnew, Engineer in charge, Mount Weather, Virginia. Andrew Brown, Mining Engineer, Tus-caloosa Branch. In addition Albert L. Toenges, Supervising Engineer, Bituminous Coal Mining Section, Pittsburgh, contributed his experience in coring coal beds. The author's experience in the use of cores within the limits stated has been confined to the brown iron-ore work described by Brown and coring bauxite and clay in Arkansas. Design and Standardization of Core Barrels Bureau engineers are primarily interested in obtaining core that will best represent

Jan 1, 1949

By J. R. Thoenen, M. C. Malamphy, G. K. Dale

THE beginning of the war and the events leading up to it precipitated a near crisis in the aluminum industry. Demands for the metal reached proportions far beyond the prewar production capacities and, in addition, the submarine menace seriously curtailed the importation of bauxite from South America, hitherto a chief source of high-grade ore. The situation required an intensive search for domestic ore to augment the reserves and in October 1941 Congress directed the Department of the Interior to investigate the extent, mode of occurrence, and quality of bauxite in the United States. In December of that year the Bureau of Mines and the Geological Survey began the search for bauxite in Arkansas, where more than 90 per cent of the domestic ore had been produced and where the greatest amount of bauxite was known to occur. The program involves the geophysical and geological investigation of the Arkansas bauxite region and the core drilling of areas considered favorable for the occurrence of bauxite deposits. Cores taken from the bauxite-kaolin zone are sampled and analyzed in the Bureau of Mines laboratory in Little Rock. The information from each of the deposits discovered is then assembled, the bauxite is graded with respect to its possible utility, tonnage estimates are made, and the whole is presented in the form of a war minerals report. Thirty-eight new bauxite deposits had been discovered and investigated at the end of the calendar year 1944, and the presence of several others had been indicated by the drilling. More than 5000 holes had been drilled throughout the bauxite region, and more than 60,000 chemical analyses had been made of samples taken from the bauxite-kaolin zone. A study of the chemical analyses led to certain general conclusions not only with regard to the chemical composition of Arkansas bauxite, but also with regard to its component minerals. Charts and diagrams based on these conclusions have been developed for practical use by the Bureau of Mines: (I) to serve as a check against laboratory analyses, (2) to present tonnage estimates of ore bodies based on mineral composition, (3) to illustrate the relationship of tonnages of bauxite to the alumina, silica, and iron content, and (4) to serve as a control for mining operations by providing a means for quick estimates of the value of the ore from a partial analysis of its chemical constituents. The use of charts and diagrams similar to those discussed in this paper is not new. The use of the trilinear diagram for studying the ultimate analyses of coals as originally proposed by Ralston in Bureau of Mines Technical Paper 93 (1915) showed that the various ranks of coal fell in different areas on the diagram and that volatile matter, calorific value and other properties could also be plotted by the use of contours. A considerable subsequent literature, largely on classification of coals, has accumulated since then, showing the utility

Jan 1, 1945

By B. L. Averbach, E. E. Underwood

The vapor pressure of zinc in equilibrium with solid ß AgZn alloys has been measured by the dew-point method. The thermodynamic activities of silver, and the molar heats of formation have been calculated. Similar measurements have been made for the ternary alloys formed by adding gold to AgZn. An apparent particle size effect has been observed for AgZn filings. The vapor pressure of zinc over filings is 15 to 20 pct higher than over the solid alloys. STATISTICAL methods have been used to inter pret the thermodynamic activities of the components of a solid solution in terms of average equilibrium atomic configurations. In some cases, the atomic arrangements can be measured by X-ray methods, and the results are usually expressed in terms of short range order parameters. Only in the cases of Cu³Au and AgAu have there been sufficient X-ray and thermodynamic data to verify the assumed correlation between the X-ray and the thermodynamic measurements. In Cu³Au the agreement is good; negative deviations from Raoult's law are observed and the number of Cu-Au nearest neighbor pairs predicted on the basis of the thermodynamic treatments agrees quite well with the number of such pairs observed by the X-ray methods. The ß brass alloys present a different set of conditions. The ordering is so rapid in these alloys that the disordered state cannot be retained on quenching. In contrast, the disordered state in CuAu is easily retained on quenching. On heating, the ordered ß brass loses its long range order continuously as the critical temperature is approached; in Cuau the order decreases slightly on heating and then drops discontinuously to zero at the critical temperature. These differences indicate that the short range order configurations in ß brass systems may be of a different character than in Cudu systems. However, X-ray measurements of local order cannot be made in the Cu-Zn alloys because of the similarity in scattering factors. The alloy AgZn is isomorphous with CuZn, however, and recent experiments have indicated that there is a good possibility of observing short range order in this system. Another complication arises in the case of ß AgZn. The disordered body-centered cubic structure exists above 280°C. On quenching from above this temperature an ordered structure of the cesium-chloride type is formed. On slow cooling, however, a complex hexagonal structure, the 3 phase, is produced; and if an ordered quenched alloy is reheated the phase begins to form above 80°C. It is thus difficult to study local order by X-ray methods in single crystals of AgZn since the C phase formed on heating does not necessarily return to a single crystal of the original orientation. This problem has been met, however, by adding a few percent of gold to the AgZn. The gold suppresses the formation of the c

Jan 1, 1952

By Taylor Cole, William T. Schneider

Drilling in West Texas during 1941 was more active than in any year since 1937, a total of 2325 wells having been drilled. Pre-Permian exploration was the greatest in the history of the area; 106 wells tested pre-Permian formations during the year. Wildcatting reached the peak since 1937, with 135 wildcats, of which 20 per cent were producers. The wells were drilled to a greater average depth than in any previous year. Slim-hole drilling was the common practice, using drilling equipment that is largely portable. Because of deeper drilling, more attention was paid to mud fluids, especially the use of materials to reduce water filtration. There has been slight improvement in the protection of the pay horizons while drilling by the use of reverse circulation, and drilling-in with oil as well as low water-filtration muds. The practice of setting and cementing the oil strings through the producing formation and perforating opposite the pay zones has increased in the fields producing from sands. It is doubtful whether this practice is of unusual value in dolomitic limestone fields. There have been few if any technological improvements in obtaining necessary information on the pay sections penetrated, by coring, core analyses, better sampling, and more detailed drilling time. However, more operators are beginning to realize the necessity of good samples. For a proper study of the reservoirs in West Texas, it is essential that better samples be obtained, that more core analyses be run, and that better methods of obtaining drilling time be initiated. It should be noted that increased drilling speeds and slim-hole drilling have tended to reduce coring and core recovery and have not aided in obtaining good subsurface samples. In fact, fast drilling speeds and slim-hole drilling have reduced the cost of drilling operations, but with the sacrifice of much needed subsurface information. Larger quantities of slower-reacting acid are being used per well. There has been improvement in shooting, in that a greater number of quarts per foot have been used and an attempt has been made to concentrate the shots opposite the pay zone. The use of mud logging to determine the characteristics of the pay section increased considerably over the year 1940. There has been a slight increase in obtaining reservoir information in the new fields, such as bottom-hole sampling, bottom-hole pressures, and records of gas, oil, and water withdrawals. However, there is great need for more data on these subjects, particularly accurate information regarding gas and water volumes. There are three repressuring projects and a fourth is nearly ready for operation in the Kermit field. There is one repressur-ing project in the Payton field and one in the North Ward field. So far, the gas-injection projects have not shown very impressive results. As yet, there are no water-flooding projects or water-disposal projects in West Texas. Not including gathering lines within the fields, 222 miles of feeder pipe lines were

Jan 1, 1942

By Chung Wang

CHINA now leads the world in antimony production, having contributed during recent years something over 60 per cent. of the world's production. The history of the antimony industry of China dates back to 1897 when the Tai Shing Co. was formed, under contract with the Hunan. Bureau of Mines, for the smelting of the ore to crude; and in 1908 the Wall Chang Mining & Smelting Co. was formed for the smelting and refining of the ore and crude to regulus. The writer was then asked to take charge of the erection and control of this first plant for regulus production in China and has, since then, been more or less connected with the antimony industry in this country. This paper contains the results of many years' experience in connection with the Wah Chang Mining & Smelting Co., Changsha; the Pao Tai Mining & Smelting Co., Wuchow; the Loong Kee Smelting Works and the To-Cheng Smelting Works, Hankow; as well as information gathered from various other small smelters, scattered in different parts of the Provinces of Hunan, Hupeh, Kwangsi, and Kwangtung. An idea of the growing importance of regulus production in this country can be gleaned from the fact that, within a period of about 8 years, the export of regulus from Hunan alone jumped from 3 tons in 1908 to about 6000 tons in 1915; that a production of about 23,000 tons of regulus per year could easily be effected from all the smelters, as tabulated below, most of which were erected a year or two ago under the stimulus of the war booms, if the price at Hankow were to stay somewhere about $900 (Mexican) per ton, half of what it was at its height, thus enabling the utilization of ores from the hinterlands of the provinces; and even under the present ruling of prices and the closing of the less-favored smelters, the production of regulus should not be less than 12,000 tons per year.

Jan 4, 1918

By Michael Bradbury

INTRODUCTION A major change in financing exports in recent years has been the decreased importance of subsidized export credits, following the commitment of the OECD countries to eliminate the subsidy element. Subsidized export credit rates are now often more expensive than market rates as the financing for exporters has decreased in volume and importance. The forfait market, in recognition of this decreasing importance, provides a rapidly expanding source of nonrecource finance for exporters. The following is a step by step guide to what it is, how it works, its benefits and problems. WHAT IS FORFAITING? Forfaiting is not new. It has been used in Europe for about 25 years to provide export finance for both capital goods and commodities without recourse to the exporter. Although long the preserve of exporters in Germany, and more lately Italy, forfaiting is now used increasingly by exporters in Great Britain, the United States, Canada and Scandinavia. It is a fairly simple operation with easy straight-forward documentation. The transaction involves the purchase by the forfaiting bank of a bill of exchange or a series of bills without recourse to the exporter. These bills will have been drawn by the exporter, accepted by the importer, and will usually bear the unconditional guarantee of the importer's bank. They are normally drawn payable at intervals during the credit period agreed between importer and exporter and are purchased at a discount by the forfaiter. The exporter thus obtains his cash payment and the importer receives his credit period. The forfaiter collects the amount of the bills as they mature directly from the importer. Credit periods vary, depending upon the type of goods and the country and commercial risk of the importer. The period is generally between one and five years with six monthly maturities. The usual forfait currencies are US dollars. Deutschmarks and Swiss francs and others, such as sterling, French francs, and the Scandinavian currencies are being used more frequently. CHOOSING FORFAITING Most types of financing require the continued involvement of the exporter in the financial side of the transaction during the credit period. Forfaiting has certain comparative advantages. In particular, it is possible to forfait 100 percent of the risk without recourse to the exporter, unlike government sponsored export finance schemes, where some retention of the risk by the exporter is required. In addition, exports from country sources do not present problems and forfaiting can also cover trade within the EEC. Other benefits for the exporter are: (a) The exporter's balance sheet is improved; debts are turned into cash thus improving the liquidity of the company and enhancing its cash flow. And there are no contingent liabilities for bills of exchange. (b) If the sales contract is in a foreign currency forfaiting removes the risk to the exporter of adverse movements in foreign exchange during the credit period. (c) Fluctuations in interest rates during the credit period can be ignored since in forfaiting the transaction is usually done on fixed interest rate terms on a discount basis. (d) The political and transfer risks are taken by the forfaiter. (e) The commercial risk is taken by the forfaiter. (f) The costs of administration and collection etc. during the credit period are removed.

Jan 1, 1985

By K. A. Jackson, J. D. Hunt

The discussion by Tammann and Botschwar of the transition from eutectie grouth to denrdritic plus eu-tectic growth is reviewed and applied to metallic eutectic systems. Using expevimental data on the geowth rate of the Pb-Sn eutectic, and an extrapolalion of dendritic growth rate in tin and Sn-Pb alloys , qlcantitatice prerlictiotls of the extent of the eutectic region in tin-vich Sn-Pb alloys are made. There are no experimenta1 measuvements available for detailed comparison with these predictions. EUTECTIC structures form over a small range of compositions. The theory of lamellar growth presented by Jackson and Hunt' indicates that it is in principle possible to have eutectic growth over almost the complete range of compositions between the two solidus lines. This does not occur in practice. Alloys far from the eutectic composition grow dendritically followed by a eutectic as shown in Fig. I. The transition from a eutectic to a dendritic plus eutectic interface cannot be predicted from constitutional undercooling arguments because constitutional undercooling always exists ahead of the eutectic interface.' Reasonable predictions can, however, be made using arguments originally put forward by Tammanl. and Botschwar.3 These and later workers'"*6 carried out extensive experimental investigations of the extent of the eutectic range in organic materials. They concluded that the structure formed, eutectic or dendrites plus eutectic, depended on which structure grew faster at the given undercooling. This is, of course, equivalent to the structure which grows with the smallest undercooling at a given growth rate. In this paper, we will discuss these ideas briefly and then apply them to predict quantitatively the range of eutectic growth in tin-rich Pb-Sn alloys. The temperature dependence of the growth rates of dendrites and eutectic for a typical metal alloy of eutectic composition is shown schematically in Fig. 2(a). The growth rate for the eutectic increases more rapidly with undercooling than those of the dendrites because of the short diffusion path maintained in the eutectic, see Fig. 1. For an alloy off the eutectic composition on the A-rich side, the growth rates shift as shown in Fig. 2(b). The liquidus temperature of the a phase increases, that of the 3 phase decreases, and the temperature of zero growth rate for the eutectic does not change. The curves, particularly the dendritic ones, change shape as well, but for our purposes the principal effects occur because of the change in liquidus temperatures.3-6 In an isothermal system, only a dendrites will grow above TE, Fig. 2(b). If the temperature is below TE, and both phases have nucleated, a dendrites will grow ahead of the eutectic at

Jan 1, 1968

By Don M. Jackson

The techniques for the growth and controlled, graded doping of silicon epitaxial overgrowth layers were established. Grading of- impurities such as arsenic or boron in arbitrarily chosen profiles oiler four orders of magnitude (from I X 10Lg to 1 X 10L5 cm) was accomplished. The graded structures were grown in a stepwise manner where in the profiles were approximated by growing many separate layers with small doping-level changes between layers. Masked-area growth of silicon through windows in a SiO2 masking film was acconiplished through the simultaneous injection of HCl gas 102th Sic14 in the epitaxial reactor. The HCl served to inhihit the growth of silicon on the Sz02 surface, and also to control the cross-sectional profile of the silicon mesas. silicon from the substrate was etched out through the windows, and then epitaxial material was used to fill the holes hack in to form planar diodes. Simullaneous HCl injection was adapted to control the cross-section profile of the hack-filled regions. Arsenic-huried regions beneath in te- In recent months, the epitaxial growth process in semiconductor materials technology has evolved into a complex system directed at both material improvement for better monolithic integrated-circuit characteristics and the development of new silicon structures for future integrated-circuit needs. The advent of high-temperature HC1 gas etching1 grated-circuit transistors reduced V(SAT) by slightly more than one third, bringing this parame-ter to that of an isolated component transistor. When arsenic was diffused into the starting sub-stvate, it was necessary to remove any excess arsenic in order to avoid excessive audodoping of the subsequent epitaxial layer. Oxide isolation of single-crystal regions in a substrate provided complete electrical isolation of integrated-circuit components, thereby eliminating parasitic capacitance which is inherent in standard integrated-circuit processing. The process involved the etching of deep mesas on silicon Wafers, the formation of an oxide over the mesa surface, and then the deposition of several mils of polycrystalline silicon over the oxide. The original substrate was lapped and polished allay until the mesas were left isolated in the polycrys-talline matrix. The Final components were fabri-cated in the single-crystal islands. Speed and power-handling capabilities of standard circuits were improved through the process. wherein work-damaged material is removed from the surface of the silicon wafer just prior to the silicon deposition step has made it possible to grow silicon films with structural quality that approaches that of the substrate. HBr used in the same volume ratio as HC1 etches silicon at the same rate and with the same results as HC1. Recent developments in epitaxial materials technology have occurred in the areas of precise doping control, buried prediffused regions between over-

Jan 1, 1965

By H. C. Fiedler

A high degree of cuhe-on-edge grain orientation and good magnetic properties were obtained in Si-Fe strip processed from laboratory heats containing vanadium nitride inclusions. The higher the nitrogen content the greater was the restraint on normal grain growth and the greater was the ability to undergo secondary recrystal-lization. The degree of restraint in a heat containing magnanese sulfide inclusions was slightly greater than that in the lowest nitrogen vanadium nitride heat. The high rate of diffusion of nitrogen in the temperature range in which the texture is developed makes it necessary to retard the loss of the inclusions until the texture has been developed. MAY and Turnbulll have shown that to develop the cube-on-edge secondary recrystallization texture in Si-Fe it is necessary that inclusions, such as manganese sulfide, be present to prevent normal grain growth. They showed that the driving force for the growth of the secondary grains is inversely proportional to the diameter of the matrix grains, and that the function of the inclusions is to maintain a small matrix grain size. Fast3has developed cube-on- edge texture in Si-Fe by nitriding the hot rolled band. The silicon nitride thereby formed promotes secondary recrystallization during the anneal of the final gage strip. To obtain the best magnetic properties, the inclusions must be removed from the strip after the grain orientation has been developed. Nitride inclusions have an inherent advantage over sulfide inclusions in that the greater diffusivity of nitrogen as comared to sulfur permits the use of shorter times and or lower temperatures for the purification heat treatment. The purpose of the work to be described was to examine the usefulness of vanadium nitride inclusions in developing the cube-on-edge texture and to determine the magnetic properties of oriented strip made from heats containing these inclusions. A comparison is made with a heat having had iden-

Jan 1, 1962

By J. R. Thoenen

The Bureau of Mines has used various sizes of core barrels above 2 in. and below 10 in. in diameter to core manganese, potash, coal, brown iron ore and bauxite. The paper describes in some detail the methods and types of equipment used to obtain maximum sampling accuracy. Introduction On December 11, 1946, R. D. Longyear, in his capacity as Chairman of the Subcommittee on Exploration Drilling, wrote the author requesting him to prepare a paper presenting the collective ideas of engineers in the Bureau of Mines on the design, standardization and application of core barrels using diamonds or other hard cutting media for drilling holes larger than two inches and less than ten inches in diameter. In subsequent correspondence it was indicated that similar papers covering the experience of other government agencies would be solicited and all such papers received would be combined in a symposium on the subject for discussion at the March 1947 meeting of the Mining Methods Committee AIME. In soliciting such information from other Bureau engineers, it developed that most Bureau experience had been confined to standard core size, two inches or less in diameter, and that larger sizes had been used only for special purposes. It is hoped the data contained herein will be of help to other operators in solving problems encountered in the field. Acknowledgments This paper was made possible by the request of Lowell B. Moon, Chief, Mining Division, Bureau of Mines, to all Division engineers to send to the author any data they had on the subject. Engineers of the Mining Division contributing were: M. H. Kline, Chief, Raleigh Branch. Paul T. Allsman, Chief, Salt Lake City Branch. J. H. Hedges, Chief, Tucson Branch. C. H. Johnson, Chief, Rolla Branch. A. M. Evans, Mining Engineer, College Park Branch. Wing Agnew, Engineer in charge, Mount Weather, Virginia. Andrew Brown, Mining Engineer, Tus-caloosa Branch. In addition Albert L. Toenges, Supervising Engineer, Bituminous Coal Mining Section, Pittsburgh, contributed his experience in coring coal beds. The author's experience in the use of cores within the limits stated has been confined to the brown iron-ore work described by Brown and coring bauxite and clay in Arkansas. Design and Standardization of Core Barrels Bureau engineers are primarily interested in obtaining core that will best represent

Jan 1, 1949

DETAILED programs for the Regional Meeting to be held at Boston, on Aug. 29, 30, 31, will be available on arrival at the Copley-Plaza Hotel, where registration will begin at 10 a. m. on Wednesday morning. The opening session will be non-technical in character and will be called to order at 11 a. m. Hector J. Hughes, Dean of the Graduate School of Engineering of Harvard University, and others will speak, and in the afternoon visits are to be made both to Harvard and Massachusetts Institute of Technology. Wednesday afternoon will be devoted mainly to the opening of an exhibit of geophysical instruments and methods at Tech. On the way back to the hotel a tour of Old Boston will permit the visitors to see many of the historic points of the city. A special meeting of the Board of Directors has been called to be preceded by the usual subscription dinner at the University Club at 6.30 p. m. Owing to limita-tions of room, invitations have been sent only to the usual list designated in the By-Laws, the Directors, past officers, chairmen of sections and of technical committees. The dinner and a brief business session of the Board will be followed by a technical session at the Copley-Plaza at 8 p. m. and this in turn by a buffet supper at the University Club at 10 p. m. Sep-arate entertainment is being provided for the women for the evening. Thursday will be devoted to technical sessions both in the morning and afternoon. If necessary to permit adequate discussion, an overflow session will be ar-ranged in the afternoon. In the evening, a subscription dinner will be given at the Copley-Plaza at which past-presidents John Hays Hammond and Robert H. Rich-ards will be guests of honor. It is promised that speeches will be short and dancing will be arranged for following. The women will be offered a luncheon and bridge party at one of the country clubs on Thursday, and Friday will be devoted to an all-day excursion for both men and, women. Members are asked to register promptly on arrival so that the various committees will know as early as possible for how many to provide. The major part of the technical program has been provided by the Committee on Geophysical Methods of Prospecting, and a series of papers of great value and interest in this new field has been brought together. Abstracts of substantially all of them are printed in this issue of MINING AND METALLURGY and the papers themselves will, with one or two exceptions, be avail-able in printed form at the meeting and later in the regular publications of the Institute.

Jan 9, 1928

By P. B. Crawford, W. L. Huskey

A study has been made to determine the effects of random vertical fractures existing in a reservoir matrix on the effective matrix properties and producing characteristics of a well. The study indicated that short vertical fractures may distort the isopotentials by 1 percent in the vicinity of the fracture. A correlation was developed which showed the effect of fracture density on the producing capacity of a well. The correlation indicated that fracture shape had little effect on producing capacity, but that total fracture length was closely correlated with the producing capacity. Effective values of reservoir permeability were found to correlate closely with fracture density when measured parallel to the direction of flow. INTRODUCTION In reviewing the petroleum literature, it is found that in most analytical solutions of hydrocarbon reservoir behavior the assumption is made that the rock is uniform throughout although core analysis and well logging surveys indicate that substantially all reservoirs are heterogeneous and some are fractured. Only in recent years have investigators studied the effects of reservoir hetrogeneity. Russell1 discussed the effect of fractures in reservoirs. The literature indicates that fractures greatly affect the exploitation of man reservoirs. This is described by Elkins and Skov2 and Little-field et al. 3 Several types of reservoir heterogeneity have been studied by unsteady-state methods. In 1959, Landrum et al. 4 showed that transient phenomena in hydrocarbon reservoirs could be studied by thermal models. pickering5 studied the flow of heat in stratified linear reservoirs consisting of plates of different metals separated by sheets of rubber which were suddenly exposed to a low-temperature source at one end. Cotman6 studied both laterally and vertically heterogeneous thermal model reservoirs with special reference to cross flow. Another type of reservoir heterogeneity involves the presence of highly permeable, circular lenses around or near the wellbore which was studied by Miesch7 using a thermal and a steady-state model. Many studies have been made of the effects of induced hydraulic fractures on well performance. 8-10 Work regarding vertical fractures that exist initially in the reservoir was reported by Givens, et al.11 Since there appears to be little published work on the importance and influence on reservoir performance of fractures that exist out in the rock matrix, this study was conducted to determine the effects of vertical fractures on pressure distribution, producing capacity and the effective permeability of the reservoir rock. The analogy between the flow of electrical current through a conducting body and the flow of fluid in a porous medium provides a convenient method of studying various aspects of petroleum reservoirs. For electrical radial steady-state flow,12 For steady-state fluid flow, With the above analogy, it is only necessary to establish the ratio of the values of the electrical units in terms of the corresponding flow units to make the analogy quantitative. The ratios are shown below.

By C. M. Shigley

The record of the largest magnesium plant in the country utilizing sea water as a primary raw material stands as another victory in the struggle for large-scale production of pure chemical elements from the oceans. Bromine was the first element to be economically and commercially recovered when, in 1933, a six million pound per year unit was built on the Atlantic Coast near Wilmington, North Carolina, by the Ethyl-Dow Chemical Co.' The bromine was reacted with ethylene to produce ethylene dibromide, a necessary associate of tetraethyl lead in ethyl antiknock fluid. Within eight years that plant was doubled and redoubled, and another large unit was put into operation at Freeport, Texas, taking bromine from the Gulf of Mexico. In 1940, in fortunate anticipation of the impending demand for magnesium and the limitations of the production from natural brines, the Dow Chemical Co. turned again to the sea, and designed and erected a plant at Freeport to produce 18,000,000 lb. of magnesium per year from sea water.2 In March 1941, two months after the new plant had been put into successful operation, construction of an 18,000,000-lb. Government-financed addition was started. Late in 1941, as a part of the $400,000,000 defense program intended to produce 600,000,000 to 700,000,000 lb. of magnesium per year, Dow was asked to build and operate for the Government a 72,000- ooo-lb. plant near its original plant at Freeport. Within a few days after the Japanese made their attack at Pearl Harbor, preparation of a site was started at Velasco, Texas, for the construction of the Texas plant of the Dow Magnesium Corporation—the largest known magnesium plant utilizing sea water as its raw matcrial. Less than six months after the first piling was driven, urgently needed magnesium was in steady production. Five months later, the plant had exceeded its rated capacity. It remained above rated production until the general magnesium curtailment was applied to Government-owned plants in September 1944. Credit for the construction and operation record of the Dow magnesium plant must be divided among the efforts of a very determined group of men, an extremely favorable location, and a simple process. It is with the two latter aspects of the plant that this article will deal. The site for the new enterprise was chosen near Velasco, Texas, on property bordering the Brazos River at a point approximately 6 miles inland from the original magnesium plant and 7 miles inland from the Freeport Harbor on the Gulf of Mexico. This location was far enough away from the operating units to reduce both interference from construction and the vulnerability of closely bunched manufacturing operations to the then feared air attack. Yet the distance inland was not too great for the economical construction of a barge canal from the harbor to serve both the transportation of raw

Jan 1, 1949

By F. J. Radd, R. L. McGlasson

The mechanisms of corrosion and corrosion fatigue damages to sucker rods are examined from a fundamental electrochemical viewpoint, and the relationships of sucker rod microstructures to these damaging effects are defined. The common corrosive agents in crude oil production and storage are discussed as to types of attacks that they cause. The variations of fatigue strength with alloy content, surface preparation, and stress ranges are analyzed. Finally, conclusions are drawn as to how microstructures largely influence and control sucker rod performance. INTRODUCTION Greater than 90 per cent of the crude oil produced by artificial lift methods is produced through sucker rod pumping systems. In the USA each year more than $14 million is spent for sucker rods in new and old pumping installations. It is important to make this investment a wise one. Essentially, the sucker rod system is a long series of steel rods, operating under alternating stress loadings and under mechanical vibrations, which connect the surface power source with the subsurface pump. These rods often operate in a variety of corrosive media, including water, brines, carbon dioxide, hydrogen sul-fide, and air. Basically, this paper is concerned with the problem of the behavior of certain steels in various corrosive media under high and dynamic stress patterns. The main objective of this paper is to show how, once the stress effects and the corrosive environments are defined, one can still realize structural control and beneficial influence upon corrosion and corrosion fatigue. FUNDAMENTAL DEFINITIONS AND ANALYSIS In the corrosion and stress behavior of this solid state mixture of iron and iron carbide called steel, one must analyze upon what major factors does its service life depend and of what, exactly, is steel composed. The former question can be referred to two external factors and two internal factors. The two major external factors are: 1. the nature of the stress patterns — size and range of stresses present 2. the nature of the corrosion — erosion environment — the corrodent and/or wear involved The two fundamental internal factors that govern the strength and useful life of a steel both in normal duty and in heavy-duty corrosion service are: 1. the nature of the steel volume properties 2. the nature of the steel surface properties For the latter question normal steel is defined as a solid mixture of iron and iron carbide particles, generally with certain accidental and intentional elements present. (The amount of iron carbide present is determined by the carbon content of the steel.) These additional elements generally dissolve into either the iron (ferrite) or the iron carbide (cementite) components.

Jan 1, 1955

By E. W. Mehal, R. W. Haisty, D. W. Show

The next generation of integrated circuits will probably include circuits constructed in and of GaAs. The existence of both semi-insulating and semiconducting forms of GaAs is the fact which will bring this about. In this paper we discuss the uses and limitations of semi-insulating GaAs for integrated-circuit applications. The two main areas considered are the electrical isolation that can be achieved between components on a semi-insulating substrate and the characteristics of p-n junctions in contact with semi-insulating GclAs. A process basic to attaining integrated circuits in GaAs to fully utilize the insulating properties of the substrate is selective epitaxial deposition. This process involves the deposition of a SiO2 layer onto a The trend in integrated circuits is towards the use of high-resistivity substrates or regions to achieve component isolation. The use of SiO, layers in the oxide isolation methods and the use of sapphire substrates are examples of this idea. GaAs is also a polished surface of a GaAs substrate, etching out selected area of the SiO, film to expose a GaAs surface, and deposition only onto the exposed GaAs surface. By using this process , islands of semiconducting GaAs are deposited onto a semi-insulating GnAs substrate, the islands being electrically isolated from one another by the substrate. The deposition of both p- and n-type semiconducting GaAs can be carried out in this nzanner to form p-n junctions in the island areas. This process can also be used to produce a planav structure by deposition of GctAs through a SiO, mask into holes etched into the GaAs substrate. This Putterned Epitaxial Technology (PET) is described. very promising material for use in future integrated circuits because of the existence of both semi-in-sulating and semiconducting forms. Active devices can be fabricated in the semiconducting material, and these individual components can then be electrically isolated from one another by using semi-insulating GaAs as the substrate. Epitaxial semi-insulating GaAs can also be produced thus making three-dimensional monolithic integrated circuits feasible.' This paper describes the research aimed at developing the methods for producing both two- and three-dimensional integrated circuits in GaAs, and examines some of the properties of semi-insulating GaAs as they relate to these integrated circuits.

Jan 1, 1967

By J. J. Gilman

Rates of prisnzatic plastic glide ( {1010}<2110>) in pure Cd crystals have been measured at temperatures from 158° to 276°C. The glide rate is proportional to the 2.75 power of the applied shear-stress. The activation energy is 29.2 kcal per mol. It is suggested that the rates of prismatic glide in Cd and Zn crystals are determined by the strengths of the atomic bonds across the prism planes. ALTHOUGH zinc and cadmium crystals both have hexagonal structures with nearly the same c/o ratios, their mechanical behaviors are quite different. Whereas zinc becomes quite brittle below room temperature, and cleaves readily on (0001) planes, cadmium is very ductile even at 4.2°K, and cannot be cleaved at any temperature. As part of a search for the explanation of this difference in behavior, a study has been made of prismatic glide in cadmium. It complements a previous study of the same phenomenon in zinc.1 The primary glide plane in cadmium is the basal (0001) plane, and the primary glide direction is the direction of atomic close-packing <2110>. However, if a tensile stress is applied parallel to the basal plane, then the shear stress on the basal plane equals zero so basal glide cannot occur. At low temperatures, deformation by twinning occurs; but at high temperatures, it has been found in this study that gliding on prismatic planes (1010) occurs in the close-packed direction. This is completely analogous with the case of zinc, except that lower temperatures are required. EXPERIMENTAL The experiments were done in nearly the same way as for zinc.&apos; Therefore, only the differences in the two sets of experiments will be described here; for other details the reader is referred to the previous paper. Crystals 6 by 6 mm sq were used that were grown from "Super Purity" 99.999 + pct Cd purchased from the New Jersey Zinc Co. The crystals were grown with their basal planes parallel to both the rod axis and one of the flat sides of the square cross section, A close-packed direction in the basal plane was oriented parallel to the rod axis. Gage sections were carefully machined into the crystals, and the surface damage caused by machining was removed with the same chemical polishing reagent as had been used for zinc. Thus, specimens of the same form and size as the previous zinc ones were produced. The crystals were heated to the test temperatures in a silicone oil bath (fused salts were tried first, but they reacted badly with the cadmium). An Instron tensile-testing machine was used for applying stresses to the crystals at various constant strain-rates. RESULTS The general behavior of cadmium crystals is much the same as for zinc. Only the constants that measure specific properties are different. Just as

Jan 1, 1962

By Lloyal O. Bacon

In the spring of 1952 Calumet and Hecla Inc. began a geophysical program near Shullsburg, Wis., in the Wisconsin-Illinois lead-zinc district, to assist the geological and drilling exploration programs. Sphalerite, the ore mineral in this area, occurs with a considerable amount of marcasite. In general the higher the percentage of sphalerite in the ore, the higher the percentage of marcasite; however, there may be mineralized zones high in marcasite but low in sphalerite. Orebodies in general are relatively narrow and elongated.

Feb 1, 1956

By C. A. Wert, K. C. Hsieh

Measurement has been made of the organic sulfur concentration in coal macerals using microanalytical techniques in the transmission electron microscope. This technique utilizes measurements of x-rays emitted by the sulfur atoms embedded in the hydrocarbon constituents and the bremsstrahlung x-rays generated in the matrix. It is a simple technique for thin specimens and yields reliable results. Although it can be used to measure the average organic sulfur content of coal, it is most useful in determining organic sulfur in extremely small volumes of material. Variations in organic sulfur content can be measured at a scale unimagined earlier. This TEM technique also has application for determination of organic chlorine, phosphorous, potassium and other elements often found distributed through the hydrocarbon constituent of fuels.

Jan 1, 1985