Search Documents

THOSE NOT MARKED ARE MEMBERS; MARKED THUS t ARE ASSOCIATES. HEAVY-FACED TYPE SIGNIFIES HONORARY MEMBERSHIP. JUNIOR MEMBERS ARE MARKED II. THE FIGURES AT THE END OF THE ADDRESS INDICATE THE YEAR OF ELECTION. AARONS, J. BOYD, Genl. Mgr., Chaffers G. M. Co., Boulder City, West. Australia. '05 ABADIE, EMILE R., Min. Engr Box 291, Porterville, Tulare Co., Cal. '76 ABBOTT, CLARENCE E., Genl. Supt., Iron Mines Div., 1405 Minnesota Ave., Bessemer, Ala. '04 ABBOTT, J. W., Min. Engr., "St. Omer," 123 N. Grand Ave., Los Angeles, Cal. '94 ABBOTT, Louis BENJAMIN, Chief Engr., Consolidation Coal Co., Elkhorn Div., Jenkins, Ky. '15 ABBOTT, ROBERT R., Met. Engr., Peerless Motor Car Co., Cleveland, Ohio. '12 ABE, ASAKA Yamagano G. M., Satsuma-Gori, Satsuma, Japan. '14 || ABRAHAMS, A. I., Student 1391 Madison Ave., New York, N. Y. '14 tACKER, E. O'C., Met Bethlehem Steel Co., Bethlehem, Pa. '86 ACKER, LOUIS K., JR., Min. Engr 565 Highland Place, Bellevue, Pa. '08

Jan 1, 1917

?AARONSON, ALFRED E , Vice-Pres , Mid-Co Petroleum Co, Mid-Co Bldg, Tulsa, Okla '18 ABADIE, EMILE R, Min Engr Address wanted '76 || ABADILLA, QUIRICO A, Geol Dept, Cia Mexicana de Petroleo "El Aguila," S A, Edifico "El Aguila," Esq, Calles Aurora y Comercio, Tampico, Tamaulipas, Mexico '20 ABBOTT, CLARENCE E, Gen'l Supt, Iron Mines Div, Tenn Coal, Iron & R R Co, 1405 Minnesota Ave, Bessemer, Ala '04 ABBOTT, LOUIS BENJAMIN, Chief Engr, Consolidation Coal Co, Elkhorn Div, Jenkins, Ky '15 ABBOTT, ROBERT R Met Engr, Peerless Motor Car Co, Cleveland, Ohio '12 ABE, ASAKA Fujita Min Co, Dojima, Osaka, Japan '14 ABEEL, GEORGE H, JR, Cons Min Engr, 635 St Paul Ave, Los Angeles, Cal '18 ABEL, ALBERT E, Asst to Pres, Valley Mould & Iron Corpn, Sharpsville, Pea '19 ABEL, W D, Min Engr Forum Bldg, Sacramento, Cal '19 ABELL, O J, Pres & Treas, Abell-Howe Co, 332 South Michigan Ave, Chicago, Ill '19 ABERNATHY G E Willow Springs, Mo '20

Jan 1, 1923

By Douglas Bunting

The first presentation of this paper was before the Pennsylvania Anthracite Section of the Institute in May, 1914, after which a committee was selected to verify and add to the data contained in the original paper. The author is indebted to G. W. Engel, H. W. Montz, R. V. Norris, and H. H. Otto, of this committee, for additional information. I also wish to acknowledge the courtesies extended me by a number of the mining companies for information relative to accidents, systems of proving, and mining practice. The paper should bring forth additional criticism and recommendations, which will be of value in establishing future practice relative to this subject. Throughout the northern anthracite field of Pennsylvania glacial and alluvial deposits of sand, gravel, and clay exist in varying quantities. The extent and character of these deposits are described by N. H. Darton in Bulletin 45 of the U. S. Bureau of Mines, entitled, Sand Available for Filling Mine Workings in the Northern Anthracite Basin. It is estimated that the northern field contains 10,000,000,000 tons of these deposits, or a sufficient quantity to cover the 176 square miles of coal area to a depth of about 25 ft. These deposits of sand, etc., overlying the coal measures attain a maximum depth of more than 300 ft., and are usually saturated to such an extent as to render them semi-fluid. It is this condition of fluidity that limits the mining of coal seams cropping in or in close proximity to these deposits, and it is in the interest of safer and more efficient mining methods under these conditions that the study of this subject is here presented. The dangers incident to mining under deep deposits of sand have long been realized by operators in the northern anthracite field, and much has been done to prove the contour of the rock and vein croppings underlying these water-bearing deposits of sand and gravel. Although, as far as we know, the accidents of the past have not resulted in the loss of life, except in two instances, yet nearly all were attended with more or less miraculous escapes of men working in the vicinity of the breaks, so that the probable existence of pot holes, etc.,

Jan 1, 1915

By Ralph E. Esarey, G. F. Fix

The oil and gas industry in Indiana in 1938 showed considerable improvement over the preceding year. Most of the drilling and development during the year, as in the past several years, was in the Indiana portion of the Illinois Basin, but increasing interest was apparent in the old Trenton area, for possibilities of further production in the Trenton formation and the underlying St. Peter sandstone. Interest in all other portions of the state was at a new peak, since many areas have never been prospected. Natural gas production continued to drop during 1938, since new discoveries have not been able to keep pace with the rapid decline in older areas. Oil production increased considerably, chiefly through the discovery of new fields. Older fields contributed about the same quantity of oil during 1938 as during the preceding year. There were 159 wells completed in Indiana during 1938, an increase of 25 over the preceding year. Of these, 48 were oil wells, 41 were gas, and '70 failed to find commercial production. Forty-three, or about 20 per cent, were wildcat. Six of these were productive—three oil wells and three gas wells. Thirty-nine wells on which operations started during the year had riot been completed by Dec. 31. Fourteen others were temporarily abandoned, with the possibility that several will be drilled to completion in the near future. A new oil field (Heusler) was discovered in May 1938, in sees. 1 and 12, T. 7 S., R. 12 W., Posey County. Production was found in the Waltersburg (Upper (Chester) sandstone at a depth of approximately 1775 ft. At the close of the year, Heusler field had nine producing wells and two drilling. The Point township area, Posey County, near the confluence of the Wabash and Ohio Rivers, held promise of good production from the McClosky lime, but offsets to the, discovery well had only shows of oil. The discovery well declined rapidly in production arid was finally plugged. In the Oaktown field, Knox County, a wildcat came in with a good flow of gas, extending the field to the east, and proving considerably more acreage. A new gas area was discovered in Sullivan County, and four good wells were completed. The discovery well was in sec. 35, T. 8 N., R. 10 W., and had an initial

Jan 1, 1939

By Ralph E. Esarey, G. F. Fix

The oil and gas industry in Indiana in 1938 showed considerable improvement over the preceding year. Most of the drilling and development during the year, as in the past several years, was in the Indiana portion of the Illinois Basin, but increasing interest was apparent in the old Trenton area, for possibilities of further production in the Trenton formation and the underlying St. Peter sandstone. Interest in all other portions of the state was at a new peak, since many areas have never been prospected. Natural gas production continued to drop during 1938, since new discoveries have not been able to keep pace with the rapid decline in older areas. Oil production increased considerably, chiefly through the discovery of new fields. Older fields contributed about the same quantity of oil during 1938 as during the preceding year. There were 159 wells completed in Indiana during 1938, an increase of 25 over the preceding year. Of these, 48 were oil wells, 41 were gas, and '70 failed to find commercial production. Forty-three, or about 20 per cent, were wildcat. Six of these were productive—three oil wells and three gas wells. Thirty-nine wells on which operations started during the year had riot been completed by Dec. 31. Fourteen others were temporarily abandoned, with the possibility that several will be drilled to completion in the near future. A new oil field (Heusler) was discovered in May 1938, in sees. 1 and 12, T. 7 S., R. 12 W., Posey County. Production was found in the Waltersburg (Upper (Chester) sandstone at a depth of approximately 1775 ft. At the close of the year, Heusler field had nine producing wells and two drilling. The Point township area, Posey County, near the confluence of the Wabash and Ohio Rivers, held promise of good production from the McClosky lime, but offsets to the, discovery well had only shows of oil. The discovery well declined rapidly in production arid was finally plugged. In the Oaktown field, Knox County, a wildcat came in with a good flow of gas, extending the field to the east, and proving considerably more acreage. A new gas area was discovered in Sullivan County, and four good wells were completed. The discovery well was in sec. 35, T. 8 N., R. 10 W., and had an initial

Jan 1, 1939

CARL HENRICH (communication to the Secretary*).-I have read with much interest the discussions of my paper by Messrs. A. S. Dwight, E. P. Mathewson, Win. B. Boggs, Jos. W. Richards, and W. C. Smith. Mr. Dwight's acknowledgment that he always-in lead smelting¬obtained better results by figuring A1203 as an acid in his slags, I may take as a confirmation of my views, notwithstanding his later conversion by, the late T. S. Austin to the latter's empirical view and way of neglecting the consideration of A1203 altogether in the composition of slags-letting the slags "dissolve" in Al203. I have a strong suspicion that Mr. Austin, in a large custom smelting plant at El Paso, has been able to keep the alumina percentage of his slags sufficiently low, not to give him much trouble, although I have also a suspicion that his furnace foreman may have had a somewhat differing opinion of the practical working of the "dissolving" theory,, whenever its applicability was tested to its limits. That Austin should have conceived the notion that the Ca of CaF2 would enter into a slag as CaO, seems hardly in accord with the recognized ability of that late metallurgist. It is a well-recognized fact that even small amounts of CaF2 will reduce the viscosity of a slag; but I did not think anyone ever had an idea that CaF2, in some mysterious way, parted with its F and coupled itself with 0 to satisfy a craving for CaO on the part of 802-least of all in a lead furnace. The "dissolving" theory for CaF2 was doubtless appropriate, and an improvement on figuring the Ca of CaF2 as CaO to satisfy the demand of Si02 for RO bases. However, I cannot understand the rationality of extending this "dissolving" theory to A1203 and to ZnO. It would be interesting to have more specific data from Mr. Mathewson in regard to the actual composition-analyses-of the slags made, when he had these unusually high alumina slags in Colorado. We "old" smelters all know that within certain limits, usually found out by rather tough experience, we could safely "disregard" A1203. In fact, I believe, we never really analyzed for alumina, except in slag analyses, when we

Jan 6, 1917

By J. Jones-Parra

In previous Technical Notes, W. R. Rose' and W. Purcell have discussed the capillary pressure data presented by Welge.' Welge obtained capillary pressure curves of the imbibition type in which it was necessary to apply to the apparent wetting phase a greater pressure than that of the non-wetting phase to complete the cycle and reduce the non-wetting phase saturation to low values. Rose suggests in his Note that conditions of equilibrium could not have prevailed, since the. non-wetting phase pressure must always be the greater. Pur-cell in his Note, proceeds to postulate a pore system consisting. of a series of "holes in a doughnut," in which he contends that under equilibrium conditions it is necessary to resort to negative capillary pressures before significant wetting phase displacement can take place. There is a remarkable similarity between the shape of the capillary pressure curve calculated by Purcell and those measured by Welge. It is the purpose of this Note to show that, because Purcell neglected to account for the behavior of the residual wetting phase saturation, his system was not in equilibrium during imbibition; and, furthermore, that if his system had been in equilibrium, negative capillary pressures would not have been possible. In Purcell's pore system, the residual wetting phase will form pendular rings at the interstitial spaces existing somewhere within the system, for example, such as those spaces between "doughnuts" as shown in Fig. 1. The true capillary pressure is that across the pendular ring interface, and for the system to be in equilibrium the pressure drop across all interfaces must be the same, including that across the interface in the tight pores A of diaphragm B (Fig. 1). As the pressure across the cell is reduced, the advancing interface will move into the pore from the diaphragm, but at each pressure, the curvature of the pendular rings must be the same as that of the advancing interface if equilibrium is to prevail. Since equilibrium conditions are the basis for the entire argument, it follows that pendular rings must grow as wetting phase enters the pore, that is, as the pressure across the cell is lowered. In Purcell's calculated curve, the residual wetting phase saturation remains constant as the capillary pressure decreases. Thus, his curve does not represent an equilibrium process.

Jan 1, 1953

HARRY B. BARREN Harry B. Barren, born in Cleveland, Ohio, May 31, 1888, died in Indiana Harbor, Ind., on Mar. 18, 1918. After graduating from the Case School of. Applied Science of Cleveland, class of 1910, he spent a year at the Youngstown, Ohio, plant of the Carnegie Steel Co. and the following two years with the National Tube Co. in Lorraine, Ohio. In 1913, he went to Indiana Harbor as assistant superintendent of the blast furnaces of the Inland Steel Co. Four months later, he was made superintendent. On Feb. 11, 1914, he was married to Miss Anna E. Jones in Cleveland and is survived by his widow and two sons, and by his parents Mr. and Mrs. H. A. Barren, of Cleveland, and a brother Kenneth, a lieutenant in the 309th Engineers, stationed at Camp Taylor, Louisville, Ky. CHAS. H. JOHNSON Charles Harmany Johnson died Dec. 10, 1918, at his home in New Castle, Pa., after an illness of more than four weeks brought about by a complete nervous collapse. He was born near Clinton, Lawrence Co. Pa., July 9, 1870, a son of George W. and Elizabeth A. Johnson. His parents moved to New Castle when he was two years old, where he attended the public schools of New Castle. He then attended Allegheny College, and later Massachusetts Institute of Technology where he graduated as a mining engineer. For a year and a half after completing his work at Boston he was connected with the Mesaba Ore Range in Minnesota, and then returned to New Castle and became associated with his father in the operation of the old sheet mill, which was converted into a tin mill and later sold to the American Sheet and Tin Plate Co. Since that time he has been actively engaged with his father in the limestone business and other industries. At the time of his death Mr. Johnson was general manager of the Pittsburg Limestone Co., the G. W. Johnson Limestone Co., the Lawrence Limestone Co., the Keystone Limestone Co., and the Mahoning Limestone Co., all of which have quarries in Lawrence, Butler, Blair and Armstrong counties and also in Maryland and West Virginia. He was president of the Johnson Bronze Co., the National Stone Co., and the

Jan 3, 1919

Engineering Council has been elected to membership in the Chamber of Commerce of the United States. Its representative will be Mr. Harold W. Buck, of Viele, Blackwell & Buck, Consulting Engineers, New York City, Past-president of the American Institute of Electrical Engineers, his alternate being Mr. Irving E. Moultrop, of the Edison Electric Illum-inating Co., Boston, member of American Society of Mechanical Engin-eers and American Institute of Electrical Engineers. The Chamber of Commerce of the United States was formed in 1912 and now consists of more than 1100 organizations in every state of the union, in the out-lying possessions, and of all the principal American chambers of commerce abroad. One of the chief aims is to obtain the best business thought on national questions that concern business. Members of the National Chamber have the privilege of using all the facilities of the Chamber's offices in Washington when information is desired.

Jan 12, 1919

several days before leaving Buffalo; influenza developed, and when his train reached Nashville, Tenn., he was too ill to continue his journey and was taken to the Kissam Hall Hospital, Vanderbilt University, where he died of pneumonia. He was a young man of unusual ability and high moral character, always brigh.t, happy and kind, faithful and honorable in all things; loved by both his associates and those under his authority. His life and character cannot be better described than by the following quotation from one of his superior officers: "Lieutenant Ohnsorg was a man loved by all of us, always cheerful, just and kind, with unusual executive ability. We can never expect to find a man who has his ability and fine temperament and his position can never be sled as he filled it." He was happily married and leaves to mourn his loss a wife, Constance E. (Rogers) Ohnsorg and a baby girl born since his death, Nov. 29, 1918, a father, W. H. Ohnsorg, mother, Ida May Ohnsorg, and a sister, Mrs. Stuart Strathy McNair. He was a member of the American Institute of Mining Engineers and of the Florida Phosphate Miners' Association. Lieutenant Edward Hale Perry At the height of the first great German'offensive -of'the Spring of 1918, Edward Hale Perry, of Boston, First Lieutenant, Company D, Sixth Regiment Engineers, U. S. Army, was killed on March 30, near War fusee—Aban-court, Picardy, France, while defending the Boisdes Tailloux against the terrific plunge aimed at Amiens. Lieutenant Perry was born in Boston, Jan. 23, 1887, the son of Georgianna W. and the late Charles F. Perry. After completion of his college preparatory course, he travelled for a year in South America and Europe before entering Harvard with the class of 1910. It might have been regarded as the natural thing for Perry, upon graduation, to choose a path that would lead to a business or professional career at home, but there were in his character a solidity, a horror of sham, a contempt for the "soft" things, and a love-of the open which caused him to be attracted to a life of stern and sturdy reality. Accordingly, he entered the graduate mining school at Harvard, and received the degree of Mining Engineer in 1913. In the meantime, two summers spent in Western mining camps had at-

Jan 1, 1920

By A. R. Elsea, E. E. Fletcher

This paper describes a metallographic investigation of the influence of tungsten or molybdenum additions upon the transformation and precipitation reactions occurring in Co-rich Co-Cr alloys. It is shown that tungsten has little effect upon the a-ß transformation temperature range, while molybdenum tends to raise it. Both elements tend to promote the formation of ? phase, molybdenum being more potent in this respect than tungsten. HIGH temperature alloys, that is, alloys which have load-carrying ability at elevated temperatures, have been developed at an increasing rate during the past few years. This has resulted from the requirements in the design of modern aircraft engines. Although many alloys of this type are available, they have been developed on an empirical basis. Metallurgists do not have a clear understanding of the phases or structures that are responsible for these high temperature properties. In order to determine why these alloys possess this particular ability, a project was started at Battelle Memorial Institute with the object of learning more about the fundamental factors which promote high temperature strength in alloys. This study was to include a correlation of microstructure and the high temperature properties of Vitallium, an alloy which is widely used for high temperature service. Vitallium is a complex material both from the standpoint of composition and microstructure. Consequently, it was necessary to obtain informa- tion regarding the phase relationships in this alloy. The Co-Cr binary diagram was determined as the first phase of this investigation.' A second paper described the effects of iron, nickel, or nitrogen on the reactions occurring in the Co-rich end of this system.' The present paper covers a continuation of this investigation in which the effects of tungsten or molybdenum on the reactions occurring in Co-rich, Co-Cr-base alloys were determined. Preparation of 'rest Materials Two series of ternary Co-Cr-base alloys, representing Co-Cr ratios of 80:20 and 68:32 ( Cr x 100 =20 and 32 ) , were prepared containing ( Co + Cr = up to 6 pct W and up to 12 pct Mo. Melting stock consisted of electrolytic Co, electrolytic Cr, 99.9 pct pure W, and 99.9 pct pure Mo. Table I lists the chemical analyses of these materials. The melting furnace was a vertical porcelain tube

Jan 1, 1952

All the Technical PUBlications and Preprints published in 1932 are available at Institute headquarters. They are also on file in public, university and technical libraries and, when so indicated in the list, may be found in the Transactions. Copies of the Technical Publications have been mailed to those members of the Institute who are registered in the different classes: A-Metal Mining; B-Milling and Concentration; C-Iron and Steel Division; D-Nonferrous Metallurgy; E-Insti-tute of Metals Division; F-Coal Division; G-Petroleum Division; H-Nonmetallic Minerals; I-Mining Geology; K-Mining Administration; L-Geophysical Prospecting. Other members may obtain copies by writing to the Secretary. Copies of Preprints may also be obtained from the Secretary's office. Additional copies are sold at the rate of 1 cent per page; minimum charge, 25 cents. Nonmembers may purchase the papers at the prices mentioned. Metal Mining Technical Publi- Title Author Meeting Trans. cation Volume No. and Page* 484-A.45 Propeller Type Mine Fan at Moose A. S. Richardson New York 102, 88. 95 F.52 Shaft. Butte. Montana (13) Feb.. 1932 487-A.46 Progress in the Improvement of Max H. Barber New York. Methods and Equipment at Feb., 1932 Open-pit Iron Mines on the Lake Superior Iron Ranges (9) Pre. Sand Filling through Pipes and Lucien Eaton New York, 102, 33, 41 Boreholes (9) Feb., 1932 Milling And Concentration 445-B.37 Soap Flotation of the Nomulfides Will H. Coghill New York. H.19 (18) J. Bruce Clemmer Feb., 1932 461-B.38 Principles of Flotation—An Experi- I. W. Wark New York. mental Study of the Effect of A. B. Cox Feb.. 1932 Xanthates on Contact Angles at Mineral Surfaces (48) Iron and Steel Division 447-C.81 Electrochemical Potentials of Nitri- Shun-ichi Satoh New York, fied Steels (31) Feb.. 1932 450-C.82 Reaistanoe of Iron-aluminum Alloya N. 9. Ziegler New York. 100, 267. 670 E.143 to Oxidation at High Tempera- Feb., 1932 tures (8) 451-C.83 Pressure Welding of Low-carbon C. H. Austin New York. Steela with Theoretical Con- W. S. Jeffries Feb.. 1932 siderations on the Mechanism of Such Welding (42) 453-C.84 Inclusions—Tbeir Effect, Solubility C.E.Sims New York, 100, 154, 176 and Control in Cast Steel (24) 0. A. Lillieqvist Feb., 1932

Jan 1, 1932

The co-operation of the members of the Institute is earnestly sought by the Committee on Nominations, recently appointed by the Board of Directors, in its work of formulating a ticket for officers and places falling vacant in the Board of Directors in February, 1916. The Committee must present the official ticket of nominations to the Board of Directors at its October meeting. Members are, therefore, urged to send promptly their nominations for officers and Directors in order that the Committee may have an opportunity to give them full consideration. The officers to be elected at the annual meeting in February, 1916, are: One officer, known as Director and President. Two officers, known as Director and Vice-President. Five officers, known as Director. The officers of the Institute whose terms expire are as follows: President, William L. Saunders (not eligible for re-election). Past President, Charles F. Rand. Vice-Presidents, Thomas H. Leggett, District 0; Fred W. Denton, District 4.

Jan 9, 1915

By K. Leutwyler

The authors present an interesting review of various applications of rather well known theories. Their rearrangement of the original working equations is strictly computer oriented and serves well to that effect; however, the new appearance will be confusing to the slide rule-wielding members of the profession. In reviewing discrepancies existing between calculations made by Baker Oil Tools, Inc. field engineering staff members and computer output submitted based on the authors' program, the following error in concept was discovered in Eq. 4. The authors quote the length change due to helical buckling in the following form We appreciate Kurt Leutwyler's awareness of Archimedes' principle, and concur that the final term in the denominator of Eq. 4 results in a small error. Examples checked revealed less than I ft error, and corrective expressions for the four possibilities of displacement follow. The portion of the denominator within extra large brackets represents the original term W,, = weight of outside fluid displaced per unit length. The authors interpreted the expression "displaced" in general oilfield terminology as a fluid displacement, such as "mud displaced with water, etc." A review of the theory forming the basis for these helical buckling calculations discloses that this displacement is meant to be interpreted in the Archimedean sense, i.e., fluid displaced by the solid body. here the tubing and the seal nipple. Lubinski* illustrated the point by summing moments due to mechanical and hydraulic forces acting on a free body immersed in fluid. This moment summation, always in the Archi,medean sense, yields effects of the real forces, including W,, and the fictitious force on the bending mechanism. I would be interested to hear the authors' comments regarding this theoretical point, which nevertheless is not mute since its lack of recognition seems to result in erroneous calculations. We must not remain mute to Leutwyler's suggestion that these equations, although computer oriented, are confusing to the slide rule engineers. Such input information as density in pounds per gallon, pipe diameters in inches, pumping rate in barrels per minute and pipe length in feet is not confusing to most of us. Yet there may be some rugged individuals in field positions who carry tables of conversion constants and have committed to memory such items as coefficients of thermal expansion and Poisson's ratio; however, even this type of individual would welcome a simplified equation occasionally. M

By Tony B. Szwilski, K. Unrug

INTRODUCTION Since the introduction of longwall coal mining systems, reliable predictions of roof support requirements at the face and the roof caveability in the gob area have been major contributors to the success of the longwall face by means of safety and face productivity. That is, the successful operation of a longwall is well-served by good regular caving of the gob. In recent times, with the advent of increased coal face mechanization and capital investment, the evaluation of the feasibility of longwall mining has become essential. In the United States, where a face unit for a face length of about 150 metres may cost around $6 million, a quantitative system that would assist in selecting the best equipment for the coal would prove extremely beneficial. There have been many such varied investigations in the past few years. A vast -amount of work has been invested principally by West Germany [3, 7, 8, 91 , Poland [I, 101 , United Kingdom [4, 5, lo], France [4], and South Africa [4]. It is the object of this paper to review this previous research work and give an outline that may be used as guidelines for long- wall evaluation. Essentially, for the initial design phase for a longwall system, account must be taken of the geometry of the coal panel, its position relative to the surface (depth), direction of the coal cleat system, faults and in-situ stresses and other neighboring workings in the same coal seam and other seams both above and below. The advance of the coal panel disturbs the stress field and in doing so creates an abutment zone around the face. At this stage the condition of homogeneity of the surrounding rock mass does not apply. The magnitude of the rock strata pressure may exceed the ultimate strength of the rocks and create zones of clastic, plastic and elastic material, the limits of which are difficult to determine. The collapse of the gob and resulting expansion of the displaced waste roof rock, create a statically undefined support complicating an already unclear rock structure. For example, it is often a point of debate whether, indeed, the vertical strata pressure develops to regain the original magnitude of virgin stress. Under these post-failure circumstances an analytical approach based on simplified and idealized assumptions can only be considered a very general approximation. Theoretical concepts, however, may be adequately supplemented by empirical methods that are based on numerous underground observations and surveys [3, 4, 7, 8]. These methods employ the use of rock indices that very handily correspond to the competence of the roof rock mass. Scale model work [3, 41 , using equivalent materials representing the surrounding rock mass within the coal seam zone, have given valuable qualitative and sometimes quantitative data in addressing the behaviour of the rock mass around longwall panels. To characterize the state of art of caveability predictioqthe principal concepts will be reviewed with special emphasis placed on practicality for the planning of longwall operation. It has been the general observation of the authors that many of the literature surveys published in English often neglect reference to other international mining literature. It is with this point in mind that an overall review has been written including mining concepts identified with the principal coal mining countries. THEORETICAL CONCEPTS Arching Theory For the development of this theory, assumption has been made that an extracted height, h, in a coal seam results in an extracted panel of width, w . Also, the coal seam is horizontal and the rock strata of both the roof and floor are homogeneous. The primary (virgin) stress distribution will change in the roof as well as the floor. As a result of lack of support caused by the excavation (in the gob area) an additional load is developed due to the redistribution of the load around the sides of the panel, referred to as the abutment, R, where: [ ]

Jan 1, 1982

By Bauer. Larry G.

The vast coal reserves in the Wyoming, Montana, North and South Dakota region are sufficient to supply the total energy needs of the United States for several hundred years. Not only is there an abundance of this sub-bituminous and lignite coal available, but it is easily obtainable by strip-mining . The overburden varies from several feet to several hundred feet. This western coal has yet another asset, namely, a low sulfur content. Whereas eastern and midwestern coal has a sulfur content of 2.5%, the upper Great Plains coal contains sulfur in the 0.5% range. The importance of the sulfur content of the coal is a direct result of federal government emission standards for sulfur dioxide (SO2). Hand (1) points out that "sub-bituminous coals and lignites have a propensity for retaining this sulfur in the ash under certain conditions which is not evident in higher rank coals." This would tend to reduce further the SO2 concentration in the combustion gases of boilers. Western coal is no panacea, however, in that it is far removed from most population and industrial centers. Furthermore, the moisture content of the coal varies from 20 to 40%. This moisture is almost exclusively inherent, that is, it is chemically and physically bound to the organic matter of the coal. It is believed that the water forms a part of the coal structure perhaps as water of hydration of organic salts or organic acids, perhaps by hydrogen bonding, or perhaps by simple adsorption (2). The primary market for this coal is the electric power industry. Lesser markets will be as coke for the steel industry and possible as a raw material for coal gasification and coal liquefaction plants.

Jan 1, 1983

By R. Maddin, A. Lawley

Single crystal Mo-Re alloys (99.99+ purity), grown by electron bombardment floating zone heating, were deformed in tension at temperatures from -196° to +200°C. At -196oC, Mo-6 pet Re and Mo-20 pct Re alloys deform by slip on systems of the type (101) [1ll]. Above-78oC, the operative slip system is of the type (112) [111], (101) [1ll], or (211) [1ll], depending upon orientation. Mo-39 pct Re alloys deform by twinning and slip at all test temperatures with a (112) [111] type twinning system. Critical resolved shear stress for slip and twinning is calculated as a function of composition and temperature, and the mechanical properties compared with those of less Pure polycrystalline alloys. HEXAGONAL close-packed rhenium, c/a = 1.615, is highly soluble in molybdenum. The bee molybdenum-rich solid solution extends to approximately 42 at. pet Re* at 2500°C,' Fig. 1. Recent work on polycrystalline alloys has shown conclusively that the addition of rhenium to molybdenum improves both the fabricability and the low-temperature ductility.2"5 Similar behavior is observed for W-Re and Cr-Re alloys.5 Initially, Geach and Hughes2 found that the Mo-30 pct Re alloy could be cold rolled to approximately 90 pct reduction before the onset of cracking. The remarkable effect of the rhenium was later confirmed by Jaffee et al. 3-5 with an optimum condition of maximum strength combined with maximum ductility at the Mo-35 pet composition. At higher rhenium contents, the ductility was severely impaired due apparently to the presence of brittle tetragonal s phase, Fig. 1. In the Mo-35 pet Re alloy, at least 110 ppm (parts per million) oxygen could be tolerated before cold workability was reduced. By comparison, the corresponding tolerance figure in unalloyed molybdenum is ~ 10 ppm. The effect of rhenium was considered in terms of: 1) a reduction in oxygen solubility in the lattice; 2) a redistribution of intergranular oxide from grain boundary films to isolated spheres; and 3) the promotion of twinning as a further mode of plastic deformation. Paradoxically, twinning is often associated with brittle fracture in iron and the silicon irons.6'7 Work to date has been restricted to are-melted and powder metallurgy polycrystalline material of ~ 99.9 pet purity. The present investigation was initiated for the purpose of determining the mode and crystallography of plastic deformation of a series of bee Mo-Re alloy single crystals over a wide temperature range from -196o to +200°C. Using high-purity zone-melted material (~ 99.99 + pet purity), the specific role of rhenium in the molybdenum lattice may be understood more fully since effects due to grain boundaries and oxide redistribution will be absent. At the same time, the study provides a comparison of single and polycrystalline deformation behavior. EXPERIMENTAL TECHNIQUES A) Preparation and Purity of Single Crystals. Alloys in the form of either are-cast and swaged or sintered and ground bar, 0.120 in. diam, were obtained from the Chase Brass and Copper Co. Alloy single crystals ~ 8-in. long were grown from the

Jan 1, 1962

By D. E. Peacock, B. Harris

Thermal-expansion and electrical-resistivity measurements have been carried out below 400°K on niobium and two niobium alloys containing tungsten. For anonaly in the expansion us temperature curve below aboct 300°K. This reslt is consistent with an earlier obsercation that Young's modilus joy Cb-132 lms an unusiully strong -tenperati-e dependence below roon temperature. No anonulous behavior was observed in the resistiuity vs temperature curve for either alloy or in the magnetic susceptibility us tenperature curve for Cb-132. These results are disclssed in terms of various electronic and bonding theories of the transition metals and their alloys, but it has not been possible to reach any definite conclusion as to the cause of the results obtained. ALONG with investigations of the low-temperature mechanical behavior of niobium and its alloys, some of the physical properties of these materials have also been studied. In the work described here, thermal expansion and electrical resistivity were measured below 400°K for niobium and two of its alloys, Cb-132 and D-43. In addition, the magnetic susceptibility of Cb-132 was measured over the same temperature range. The alloys are representative of two distinct tion-hardened alloy such as might find service as a turbine blade, while D-43 (Nb, 5.3 at. pct W, 1.1 at. pct Zr. and 0.08 at. pct C) is a solution- and dispersion-hardened alloy, of considerably lower strength than Cb-132. which is a potential vane material. Their significant common feature is the presence of tungsten as the principal source of solution hardening. EXPERIMENTAL TECHNIQUES Thermal-expansion measurements were made with a quartz-tube dilatometer using baths of liquid nitrogen, liquid bromoethane, and a liquid polyalkylene glycol derivative to cover the range 80 to 400 K. Results are recorded as expansion relative to that of quartz, and the probable maximum error in any value of relative expansion. All, is about il pct. The metallurgical condition of the specimens, which were in rod form. will be discussed in the section dealing with experimental results. Resistivity was measured on recrystallized wires 0.030 in. in diam using a potentiometric technique. The same baths were used for temperatures between 80' and 400°K as were used for the expansion measurements. and in addition the resistance of D-43 and Cb-132 was measured at 4.2 K by immersion in liquid helium. The maximum expected experimental error in any resistivity value is about 3 pct and that in any change in resistivity about i0.05 pct. Temperatures in both sets of experiments were measured with liquid-in-glass thermometers with an accuracy usually better than 1°K. EXPERIMENTAL RESULTS 1) Thermal Expansion. In Fig. 1 is shown the relative linear expansion of recrystallized niobium. D-43. and Cb-132. The curve for Cb-132 is composed of results from several runs on three different samples. Two of the samples were annealed for an hour at 1500°C to cause recrystallization and the third was annealed for an hour at 2000'C to remove some mi-crosegregation of tungsten which was known to be present in the wrought alloy received from the manu-

Jan 1, 1967

By R. Taggart, R. H. Ericksen, D. H. Polonis

Transmission electron microscopy techniques hare been used to study the spontaneous marfensite phase that forms during the thinning of Ti-Cr alloys. The structure of this phase has been found to differ. from the hcp martensite and has been identified as a clisforted fcc lattice. The spordaneous marlensile in this system is interpreted as a metastable isomorph of the equilibriunz TiCr, phase. WHEN thin-foil specimens for transmission electron microscopy were prepared from metastable alloys of the Ti-Cr system, a spontaneous transformation occurred' when the foils contained the untrans-formed 0 phase or two-phase mixtures of the 0 and w phases. The purpose of this paper is to examine the relationship that exists between the crystal structure of the spontaneous product and that of the matrix. The differences between the martensite transformation that occurs in the bulk material and the spontaneous reaction that occurs during the preparation of thin foils are compared with the observations that have been reported for similar phenomena in a commercial titanium alloy.' A spontaneous reaction that exhibits characteristics similar to a martensite transformation has been reported to occur in thin foils prepared from the retained metastable structures of several alloy systems.1'3"7 ~ull~ observed such a spontaneous reaction in 0 brass and attributed the apparent increase in the martensite transformation temperature to a decrease in the non-chemical free energy associated with bulk strain energy. He also showed that the spontaneous product did not have a specific habit plane, but that its orientation relationships to the parent matrix were dependen on the thickness of the transforming region. It has also been pointed out by Breedis6 that in thin films the absence of the constraints imposed by a bulk matrix can cause different requirements for the martensite plate interface and lattice distortion which is reflected bv a dependence of the transformation mechanism on the specimen geometry. In the case of the spontaneous reaction reported for Au-Zn alloys7 a definite habit plane was determined and shown to correspond with the habit plane calculated on the basis of the Bowles and Mackenzie crystallographic theory of the martensite transformation.'- lo EXPERIMENTAL PROCEDURE A series of titanium alloys containing 5.5, 5.9, 6.4: 7.6, 8.0, 11.3, and 18.7 at. pct Cr were prepared from high-purity (iochrome) chromium and iodide-grade titanium by levitation melting. The experimental procedure used for sectioning the alloys and for thin-foil preparation has been reported in an earlier paper.' X-ray diffraction patterns were obtained using a 114-mm Debye-Scherrer camera and Cu-Ka radiation. In order to minimize fluorescent radiation from the specimen, a strip of aluminum foil 0.002 in. thick was placed in contact with the X-ray film. After a specimen was removed from the camera: an additional X-ray experiment was performed, to insure that no spurious lines were obtained due to the presence of the aluminum foil. The interstitial impurity analysis for the alloys used in this study was as follows: oxygen, 100 ppm: hydrogen, 30 ppm: nitrogen, 28 ppm. EXPERIMENTAL RESULTS Electron diffraction patterns were obtained from several individual crystals of the spontaneous marten-

Jan 1, 1970

By Roger A. Gregg, Barry J. Piearcey

MANY of the nickel-base superalloys developed recently for use in the as-cast condition exhibit a massive "white-etching" constituent1 in the inter-dendritic regions. Commercial alloys in this category are SM 200,* IN 100, INCO 713, and Nicrotung. The appearance of a similar microconstituent in nickel-rich Ni-A1-B alloys has been reported by Schijbel and Stadelmaier. Their investigation revealed that this constituent was the binary eutectic of the terminal nickel-base solid solution and the inter metallic based on Ni3A1. This binary eutectic is degenerate and NhA1 is the major phase. At lower temperatures the eutectic composition lies within the NkA1 phase field and under equilibrium conditions is single-phase NisAl. Taylor and F&apos;loyd3 have shown that in Ni-Al-Cr alloys containing at least 8 at. pct Cr, liquid compositions which solidify by the eutectic reaction in the nickel-rich portion, precipitate nickel-base solid solution and NiAl rather than nickel-base solid solution and NkA1 in the binary Ni-A1 system. Since the nickel-base alloys contain chromium in excess of 8 at. pct and are further alloyed with one or more of the elements titanium, cobalt, molybdenum, or tungsten, it is possible that the eutectic could contain NiAl rather than NisAl. In addition, Benson4 has reported that in low-nickel austenitic high-temperature alloys, which possess Ni/(Al + Ti) atomic-weight ratios <18.0, the Ni (Al, Ti) phase may precipitate from the melt during solidification. Since SM 200 and similar high-temperature materials were developed from alloys which were designed for solution treatment, the appearance of a eutectic would indicate that the limit of solid solubility has been exceeded. The purpose of this note is to confirm that the massive white constituent in the complex nickel-base alloys investigated is based on the binary eutectic Ni + NbAl and that the limit of solid solubility need not be exceeded to produce it, in common with other observations of cast alloys. Successive polishing of a sample of SM 200 showed that, in agreement with Schobel and Stadelmaier, particles of the constituent were spherulitic and in particular were a) situated between cored dendrite arms, Fig. 1, and b) nucleated at the surface of dendrites, Fig. 2. The Ni/(Al + Ti) atomic-weight ratios for the nickel-base alloys which were observed to contain the massive eutectic constituent in the interdendritic regions are 12.1 (Nicrotung), 9.2 (IN loo), 19.5 (INCO 713), and 14.5 (SM 200). However, the results of X-ray analysis of these alloys in the as-cast condition failed to reveal the presence of the Ni (Al, Ti) phase. An electron microanalyzer was therefore employed to analyze the composition of this constituent in SM 200. The results of analyses of representative particles are as follows5: 8.4 at. pct Ti, 8.8 at. pct Co, 5.5 at. pct Cr, 0.9 at. pct W, 12.8 at. pct Al, and 63.6 at. pct Ni. Assuming that

Jan 1, 1964