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February 20th, 1872. THE Institute assembled on Tuesday evening, in the building of the University of Pennsylvania. In the absence of President Thomas, Vice-President Raymond occupied the chair. The Institute was welcomed in an eloquent and thoughtful address by Prof. J. P. Lesley, to which Mr. Raymond responded. Invitations were announced from the proprietors of Sellers' Tool Works, Whitney's Car-wheel Works, the Baldwin Locomotive Works, Lewis & Brothers' White Lead Works, the Southwark Foundry, Harrison's Boiler Factory, the University of Pennsylvania, and the Academy of Natural Sciences. The following gentlemen, being duly recommended by the Council as members and associates, were unanimously elected Alexander, John S., - Philadelphia, Pa. Biddle, E. R., - New York. Britton, J.. Blodget, - Philadelphia, Pa. Brooks, Maj. T. B., - Marquette, Mich. Brown, D. P., - Pottsville, Pa. Canfield, Edw., - Dover, N. J. Cogswell, W. B., - Franklin IronW'ks, N.Y. Cornwall, Prof. H. B., - New York. Edwards, Daniel, - Danville, Pa. Estabrook, John D., - Philadelphia, Pa. Firmstone, William, - Easton, Pa. Fritz, John, - Bethlehem, Pa. Gignoux, Charles, - New York. Grant, E. M., - Tuskegee, Ala. Humphreys, A. W., - New York. Ingham, W. A., - Philadelphia, Pa. Keyes, W. S., - Eureka, Nev. Kimball, Dr. J. P., - New York. Law, Charles, - Pittston, Pa. Neilson, W. G., - Philadelphia, Pa. Newberry, Prof. J. S., - New York. Pearse, John B, - Steel Works P. O., Pa. Ricketts, P. De P., - New York. Scranton, Col. Charles, - Oxford, N. J. Sontag, Hugo, - Cologne, Prussia. Steele, Thomas C. - Summit, Pa. Wharton, Joseph, - Philadelphia, Pa.

Jan 1, 1873

Furnace Builder. Engineer with extensive experience in furnace building. Position with well-established firm, branching into new fields. Location Ohio. 11-1343. Erecting and Operating Engineer to take charge of erection of gas-producer equipment and to teach customers how to operate such equipment. Location Ohio. Salary $250 per month. R-1339. Assistant Professor in Mining School, for instruction work; must have had experience in ore dressing and metallurgy. Location Missouri. Salary $1500-$2100 per school year (8 mo.). R-1332. Consulting Engineer, familiar with construction of artesian wells to act in a consulting capacity. Location New York City. R-1324. Mining Engineer and Investigator to do non-metallic mineral investigations in both field and office for United States Government. Position will last at least a year, and may become permanent. Location Washington, D. C. Salary $1800-$2700 depending on qualifications of appointee. R.-1317. Crushing Plant Superintendent, cement mill and construction experience essential. Prefer man who has had limestone crushing experience. Location New York. R-1314. Assistant Professor of Coal Mining, must be a graduate of mining engineering and have had some coal mining experience. Location Philadelphia.. Salary $2200 for school year of 10 months. R-1312.

Jan 9, 1919

Jan 1, 1922

By R. H. Atkinson

With the object of improving the melting, casting, and working of palladium and 95.5 pct Pd-4.5 pct Ru, the effects of different melting atmospheres (reducing, oxidizing, and neutral), crucible linings, and annealing atmospheres have been studied. Some interesting observations are included about the solubility and diffusion of gases in palladium. THE object of the present work was to ascertain the effect of oxidizing, inert, and reducing ambient atmospheres on the melting and casting of palladium and a Pd-Ru alloy commonly used for jewelry. The need for such a study was indicated during World War I1 when jewelers experienced difficulty in their attempts to make small castings of the torch-melted Pd-Ru alloy by the lost-wax process. When the metal was melted under oxidizing conditions similar to those used for platinum, the castings were gassy; on the other hand, if the melting atmosphere was reducing, the castings were hot-torn and brittle. General Experimental Procedure Pure palladium sponge (99.9 pct Pd) and pure ruthenium powder (99.8 pct Ru) were used for making small ingots (50 g) of palladium and 95.5 pct Pd-4.5 pct Ru by induction melting. The coil, 3 in. high by 2 in. ID with 16 turns, was energized by a 20 kva Ajax high frequency converter. The melting crucibles, so-called sand crucibles, which were made of a highly refractory fireclay, were lined with different materials, including proprietary magnesia, alundum, zircon, and zirconia

Jan 1, 1957

By H. E. Ellis, O. L. Patterson, Granville Dutton

A large-scale water-injection program for the Holt Bryant reservoir of the Delhi field has been established by means of the new automatic multi-pool analyzer. The objectives of this program were to increase reservoir pressure and eliminate a cross-dip gradient of 200 psi. Pressure increases during the first 15 months of operation have allowed for increased oil production rates of 2,600 BID or 25 per cent. To determine the required water injection it was necessary to predict natural water influx ram. Elimination of the pressure gradients required the water-injection program to account for the fluid migration and pressure interaction between segments of the reservoir. An integral part of the ana1ysis included the determination of in-place volumes of oil and gas. The operation of the automatic multi-pool analyzer in determining the water-injection program is described. New features of the analyzer inc1ude an automatic maferial balance analog and a leart-squares computer for determination of unknown reservoir properties. Operational procedures are sufficiently simple to allow direct use by reservoir engineers on a routine basis. The rapidity and accuracy with which problems may be solved permit repeated ana1yses as a check upon reservoir performance. INTRODUCTION This paper describes the use of a new analog com- puter in determining the optimum injection program for a complex reservoir. The Holt-Bryant (Fig. 1) is the major reservoir in the Delhi field of Louisiana. Production is from the Tuscaloosa at subsea depths of 2,970 to 3,286 ft. The sand dips to the south and southwest from three to five degrees. The reservoir is approximately 12 miles long and varies in width from 1/2 to 2 miles. Various calculations have placed the initial volume of oil in-place in the wide range of 275 to 355 million STB. Two small gas caps were initially present in the reservoir. The Holt-Bryant reservoir was discovered in Dec.. 1944, and was fully developed with 188 producing wells by 1948. After development was completed, an east-west pressure gradient began to establish itself. This

Jan 1, 1957

Jan 1, 1902

By William Laird

The predominent method of coal mining in the United States for years has been room-and-pillar mining. The reason for this has been the advantages of room-and- pillar method which is a relatively flexible system and its capital investment. The room-and-pillar method permits some selectivity in mining, especially where gas wells, faults and possible coal quality may be a factor. The mobility of continuous and conventional mining equipment used to develop entries may also be used for retreat mining of rooms and pillars. Longwall mining of coal takes place along a long straight face, or wall, blocked out between two butt or panel entries. The long faces or walls are normally projected in lengths of 61 to 183 m (200 to 600 ft) in this country. The longwall method of mining had its beginning in the United States during the 1800's. During that period, pack wall and wood posts were used for roof support. The longwall face was mined by miners using picks to undercut the coal. To keep the coal face from turning over, short wood posts called sprags were set in a slant position as the coal face was undercut to the depth of two to three feet. When the under-cutting cycle was completed, the sprags were removed to permit the coal to fall from the roof pressure. The longwall mining of coal did not take a firm hold during the 18009s, and room-and-pillar prevailed. In the early 19009s, steel jacks were introduced, and along with it, the modified caving theory. In March of 1950, a retreat longwall mining system, utilizing a plow, manually operated props, wood cribs and chock releases, was installed in one of Eastern Associated Coal Corp.'s mines.

Jan 1, 1981

By D. H. Yardley

GEOCHEMICAL investigation of trace elements in surface materials was begun near Ely, Minn., in 1953 along the basal contact of Duluth gabbro with Giants Range granite (Fig. 1). This article presents data on the distribution of copper and nickel in till and in stream sediments in the area and proposes an explanation for the types of distribution found. The Duluth gabbro, one of the world's largest basic intrusives, intrudes rocks which range in age from Keewatin to middle Keweenawan. Within the test area the gabbro is in contact with granite except for short sections where it is in contact with remnants of iron formation. Sulfide mineralization occurs within the gabbro, near and parallel to the basal contact for a distance of several miles. Schwartz and Davidson' have described the geologic setting of the mineralization. The sulfides, believed to be syngenetic, include chalcopyrite, cubanite, pentlandite, pyrrhotite, and minor amounts of bornite. They occur disseminated in the silicates and as small interstitial masses. The ratio of copper to nickel is about 3.8:1, based on 66 chemical analyses of rock samples from various outcrops (Ref. 1, p. 702, and Ref. 2). Test Procedures: With specified exceptions, all nickel and copper tests were made by the chromo-graph method,:' which measures the intensity of a colored spot formed by a reaction between the metal being determined and special reagent paper. The intensity is then compared to the intensity of spots prepared from samples of known metal content. Details of the test procedure are outlined in another article (Ref. 4, pp. 77,78). All soil samples tested in this investigation to date have been weighed on an analytical balance. However, a volumetric scoop designed to provide about 0.1 g of soil adds to the speed and ease of testing and has been found to give satisfactory results (Ref. 5, p. 531, and Ref. 19). The size of the samples used for the tests was 0.1 g. Whenever such small samples are used there is some question as to whether they are representative of the several grams in the field sample. Many repeat tests of the samples used in this investigation demonstrated that results can be reproduced within the limits of accuracy of the method without formal mixing beyond that inherent in screening the soil fractions. Furthermore, the 0.1 g is probably as representative of the field sample as the field sample is of its area of influence. Hawkes and Lakin (Ref. 6, p. 291), who considered the general problem, compared ground and quartered bulk samples of 500 g with 5-g grab samples. They concluded that "there is no significant loss in accuracy of data by substituting grab samples for bulk samples." The term soil implies somewhat different things to the geologist, engineer, and soil scientist.' For convenience the term as used in this article refers to unconsolidated material (the mantle) overlying bed rock. Sampling Procedure: Samples were taken at 100-ft intervals along north-south traverse lines across the gabbro-granite contact. The soil (till) samples were taken at an average depth of 1 ft, which was below the high-humus surface layer and into clean till. Samples taken at 1-ft intervals down to ledge showed as high a metal content at 1 ft below the air-surface as at greater depths and in two instances were slightly higher. The till at 1-ft depth did not appear to differ from material at greater depths. Total depth to bedrock has been tested at only a few points and where measured varied from 1 to 10 ft. Aerial Distribution Contours and Profiles: Plotting of copper, nickel, and cobalt content in contour form (Fig. 2) shows that anomalous amounts of these metal ions occur in till over and closely adjacent to mineralized areas of the gabbro. Contouring nickel content alone, or the copper content, outlines the same target area. Contours of the copper content provide a more distinct anomaly than nickel because of the higher copper concentration. The traverses are rather widely spread for interpolation; however, drilling has confirmed the target area essentially as shown.

Jan 1, 1959

By Basil B. Zavoico

The symposium on production for the year 1942 contains no papers on the foreign situation except those on Argentina and Mexico. It has always been the policy of officers in charge of the symposium to refrain from publishing information that might possibly injure national or private interests. At the close of the war we hope again to publish full and accurate records of production abroad. Excerpts From Circular to Authors In order to facilitate interpretation of the data in this chapter, we print the following excerpts from the Circular to Authors. The field is the unit in this tabulation. In cases of fields extending across State boundaries, such as Rodessa, it is suggested that each State author treat the section of the field in his State as a unit, and by a footnote indicate that the field extends into an adjacent State. Each space in Table I may represent one of four possibilities; either it is not applicable to the particular field, or the proper entry is not determinable, or the proper entry may be determinable but is not determinable from data available to the author, or the proper entry is determinable. When spaces are not applicable, leave blank; in spaces where the proper entries are determinable but not determinable from data available to the author, please insert y; in spaces where the proper entries are determinable by the author, make such entries. y implies a Rope that in some future year a definite figure will be available. The entry of a zero is a positive declaration, and it is an important declaration where it is in order. Inability to determine precisely the correct entry for a particular space should not lead the author to insert merely y. Contributions of great value may be made by the author in many cases where entries are not subject to precise determination. In such cases the author should use his good judgment and make the best entry possible under the circumstances. For many spaces the correct entries represent the opinion of the author (for example, "Area Proved") and in such cases the entry need not be hedged to such extent as when the quantities are definite yet can be ascertained only approximately by the author. In cases under definite headings but where figures are only approximate, the author may use x. It is thought that the nearest whole numbers are sufficiently accurate for our purposes except as to percentage of sulphur in oil. If an author desires to report any other figures to tenths, he may do so. The quantity of gas produced should include, where possible, gas sold or otherwise marketed, and gas blown into the air, burned as flares or otherwise wasted. Segregation of these figures would be interesting if the authors can make such segregation. In any event, the figures should represent as nearly as possible the total quantity of gas removed from the reservoir. Under the columns on "Depth," the average depth to the top of the productive zones and to the bottom of the productive wells, when subtracted, should give the approximate thickness of the productive zone. For fields where this is not true because of unusually high dip or for some other reasons, it is suggested that the authors indicate in their text the approximate average thickness of the productive zone.

Jan 1, 1943

By James Terry Duce

The symposium on production for the year 1940 contains few papers on the foreign situation. It is probable that the foreign part of next year's symposium will be even shorter. This is due to rigid censorship in various countries, as the question of the volume of petroleum supplies has become one of great strategic importance. This is even more true than in the last war, owing to greater mechanization of armies. 'It has always been the policy of officers in charge of the symposium to refrain from publishing information that might possibly injure national or private interests. At the close of the war we hope again to publish full and accurate records of production abroad. Excerpts from Circular to Authors In order to facilitate interpretation of the data in this chapter, we print the following excerpts from the Circular to Authors. The field is the unit in this tabulation. In cases of fields extending across State boundaries, such as Rodessa, it is suggested that each State author treat the section of the field in his State as a unit, and by a footnote indicate that the field extends into an adjacent State. Each space in Table I may represent one of four possibilities; either it is not applicable to the particular field, or the proper entry is not determinable, or the proper entry may be determinable but is not determinable from data available to the author, or the proper entry is determinable. When spaces are not applicable, leave blank; in spaces where the proper entries are determinable but not de-terminable frod data available to the author, please inserty; in spaces where the proper entries are determinable by the author, make such entries. y implies a hope that in some future year a definite figure will be available. The entry of a zero is a positive declaration, and an important declaration where it is in order. Inability to determine precisely the correct entry for a particular space should not lead the author to insert merely y. Contributions of great value may be made by the author in many cases where entries are not subject to precise determination. In sucli cases the author should use his good judgment and make the best entry possible under the circumstances. For many spaces the correct entries represent the opinion of the author (for example, "Area Proved') and in such cases the entry need not be hedged to such extent as when the quantities are definite yet can be ascertained only approximately by the author. In cases under definite headings but where figures are only approximate, the author may use x. It is thought that the nearest whole numbers are sufficiently accurate for our purposes except as to percentage of sulphur in oil. If an author desires to report any other figures to tenths, he may do so. The quantity of gas produced should include, where possible, gas sold or otherwise marketed, and gas blown into the air, burned as flares or otherwise wasted. Segregation of these figures would be interesting if the authors can make such segregation. In any event, the figures should represent as nearly as possible the total quantity of gas removed from the reservoir. Under the columns on "Depth," the average depth to the top of the productive zones and to the bottom of the productive wells, when

Jan 1, 1941

By AIME AIME

REGISTRATION and licensing of engineers is now being given consideration by a special committee of the Institute, authorized at the March meeting of the Board of Directors. The subject is one that has recently been or is now actively before engineering organizations in many of the States of the Union. In Washington, D. C., the Washington Society of Engineers and the local sections of ten national engineering societies, including the A.I.M.E., recently had a joint committee investigate the subject: this committee formulating a proposed law that has been presented to Washington engineers for their consideration. At the same time, the committee has summarized the reasons for and against registration of engineers in Washington, D. C. As many of these reasons are of more than local application, they are here reprinted so that all members of the A.I.M.E. may be informed on the subject. It is expected that some report of the Institute's Committee on Registration, State Councils and Professional Development will he made at some forthcoming meeting of the Board of Directors.

Jan 1, 1932

By M. Metzger, J. C. Bilello

Microyielding in 99.999 pct Cu occuwed in two distinct parabolic microstages and was substantially indeoendent of grain size at the relatiz~ely large grain sizes stzcdied. The strain recouered on unloading was a significant fraction of the forward strain and was initially higher in a copper-coated single crystal than in poly crystals. Results were interpreted in terms of cooperative yielding and short-range dislocation motion activated otter a range of stresses, and a formalism was given for the first microstage. It was suggested that models involving long-range dislocation motion are more appropriate for impure or alloyed fcc metals. THERE are still many unanswered questions concerning the degree and origin of the grain size dependence of plastic properties. In the microstrain region, a theory of the stress-strain curve proposed by Brown and Lukens,' based on an exhaustion hardening model in which the grain boundaries limit the amount of slip per source, accounted for the variation with grain size of microyielding in iron, zinc, and copper.' This theory assumes N dislocation sources per unit volume whose activation stress varies only with grain orientation. Dislocations pile-up against grain boundaries until the back stress deactivates the source, which leads to a relationship between the axial stress and the strain in the microstrain region given by: where G is the shear modulus, D the grain diameter, a the flow stress, and a, is the stress required to activate a source in the most favorably oriented grain.3 If this or other grain-boundary pile-up models are correct, then the reverse strain on unloading would be much larger for a polycrystalline specimen than for a single crystal. Also, the microplasticity would become insensitive to grain size if this could be made larger than the mean dislocation glide path for a single crystal in the microregion. These questions are examined in the present work on polycrys-talline copper and a single crystal coated to provide a synthetic polycrystal. EXPERIMENTAL PROCEDURE Tensile specimens 3 mm sq were prepared from 99.999 pct Cu after a sequence of rolling and vacuum annealing treatments similar to those recommended by Cook and Richards4-6 to minimize preferred orientation. Grain size variation from 0.05 to 0.38 mm was obtained by a final anneal at temperatures from 310" to 700°C. Dislocation etching7 revealed pits on those few grains within 3 deg of (111). For all grain sizes dislocation densities could be estimated as -107 cm per cu cm with no prominent subboundaries. The single crystals, of the same cross section, were grown by the Bridgman technique with axes 8 deg from [Oll] and one face 2 deg from (111). An anneal at 1050°C produced dislocation densities of 2 x 106 cm per cu cm and subboundaries -1 mm apart in these single crystals. A Pb-Sn-Ag creep resistant solder was used to mount the specimens, with a 19 mm effective gage length, into aligned sleeve grips fitted to receive the strain gages. All specimens were chemically polished and rinsed8 to remove surface films just prior to testing. The synthetic polycrystal was made by electroplating a single crystal with 1 µ of polycrystalline copper from a cyanide bath. Mechanical testing was carried out on an Instron machine using two matched LVDT tranducers to measure specimen displacement, the temperature and the measuring circuit being sufficiently stable to yield a strain sensitivity of 5 x 107. At the crosshead speeds employed, plastic strain rates were, above strains of 10¯4, about 10¯5 per sec for polycrystalline specimens and 10-4 per sec for the single crystals. Plastic strain rates were an order of magnitude lower at strains near l0- '. A few checks at strain rates tenfold higher were made for reassurance that the initial yielding of polycrystalline copper was not strongly strain-rate dependent. Test procedures followed the general framework outlined by Roberts and Brown.9,10 An alignment preload of 8 g per sq mm for polycrystals, and 2 to 4 g per sq mm for single crystals, was used for all tests. These gave no detectable permanent strain within the sensitivity of the present experiments; although at these stress levels, small permanent strains are detectable in copper with methods of higher sensitivity.11 12 stress and strain data are reported in terms of axial components. RESULTS General. The initial yielding is shown in the stress vs strain data of Fig. 1. For polycrystals, cycle lc, the loading line bent over gradually without a well-defined proportional limit, and almost all of the plastic prestrain appeared as permanent strain at the end of the cycle. The unloading curve was accurately linear over most of its length with a distinct break indicating the onset of a significant nonelastic reverse strain at the stress o u, indicated by the arrows. The yielding in subsequent cycles, Id and le, had the same general character. The single crystal behavior, shown to a different scale at the right of Fig. 1, was different in that initially the nonlinear reverse strain was unexpectedly much greater than for polycrystals. It should be noted that these soft crystals had a small elastic

Jan 1, 1970

By L. W. Legerwood

During the past three decades, the oil industry has expended increasing eflorts seeking improved drilling tools or systems to reduce drilling costs. The total cost of these efforts is unknown, but it certainly amounts 10 tens of millions of dollars. Most of the "new" system that past and present investigators have sought to develop actually are old public information. In seeking to implement new-systern concepts, investigators have tested the following: impact at frequencies ranging from 6 to 300 cycles per second; electrical, mechanical and hydraulic meam of actuating percussors; bit rotary speeds up to 2,000 rpm; electric and hydraulic bottom-hole means of rotating bits; bottom-hole machines with power outputs up to 400 hp; shock waves; explosives; high-velocity pellets; flame; arc; grinding wheels; abrasive jets; erosion by high-velocity gases; chemical attack; electric current; magnetic waves; retractable rock bits; reelable drill pipe; continuous coring with reverse circulation; and automation of drilling rigs. Table I shows how these investigations are grouped for discussion purposes in this paper. In spite of these efforts to discover new and improved systems, rotary drilling main;aim its economic leadership. Undoubtedly, rotary drilling costs will continue to be reduced by rigid application of the best available technology and by development of new rotary technology. In view of the extensive past development programs, however, significant long-range improvement appears to be a research, not a development problem. Research must postulate and prove theories and principles governing variour subsurface rock-failure processes pertinent to both rotary and new systems. Ah, research must produce physical and engineering data relative to these processes. When such information is available, earth boring will graduate from an art to a science. Major improvements in rotary drilling can then be expected, and the systematic evolution of an improved drilling method can be initiated—with a strong probability for success. Development of drilling methods other than rotary drilling has been one approach investigated by the industry as a means for reducing drilling costs. Major cost-reduction efforts, however, have been centered on engineering development work aimed at incremental improvements in rotary drilling. A relatively minor effort has been expended to establish basic physical principles and engineering data pertaining to the earth-boring process which can serve as a foundation for the development of cost-cutting drilling hardware. Current oil-industry economic trends have added impetus to the need for effective programs to reduce drilling costs. However, areas for expanded future efforts should be selected only after careful study of past investigations. It is the purpose of this paper to review past and Dresent industry efforts to develop new drilling tools or systems and to suggest areas where additional science is needed. Past reviews of drilling methods have been limited to a few processes prominent at the time the reviews were made. This paper seeks to present a concise, well organized review of all methods that have received actual development or test work. The preparation of a paper seeking to review all past developments is fraught with many difficulties, not the least of which are errors in or obsolesence of printed matter used as source material and the lack of data on industry developments which have not been published. Since de-

By James Terry Duce

The symposium on production for the year 1940 contains few papers on the foreign situation. It is probable that the foreign part of next year's symposium will be even shorter. This is due to rigid censorship in various countries, as the question of the volume of petroleum supplies has become one of great strategic importance. This is even more true than in the last war, owing to greater mechanization of armies. 'It has always been the policy of officers in charge of the symposium to refrain from publishing information that might possibly injure national or private interests. At the close of the war we hope again to publish full and accurate records of production abroad. Excerpts from Circular to Authors In order to facilitate interpretation of the data in this chapter, we print the following excerpts from the Circular to Authors. The field is the unit in this tabulation. In cases of fields extending across State boundaries, such as Rodessa, it is suggested that each State author treat the section of the field in his State as a unit, and by a footnote indicate that the field extends into an adjacent State. Each space in Table I may represent one of four possibilities; either it is not applicable to the particular field, or the proper entry is not determinable, or the proper entry may be determinable but is not determinable from data available to the author, or the proper entry is determinable. When spaces are not applicable, leave blank; in spaces where the proper entries are determinable but not de-terminable frod data available to the author, please inserty; in spaces where the proper entries are determinable by the author, make such entries. y implies a hope that in some future year a definite figure will be available. The entry of a zero is a positive declaration, and an important declaration where it is in order. Inability to determine precisely the correct entry for a particular space should not lead the author to insert merely y. Contributions of great value may be made by the author in many cases where entries are not subject to precise determination. In sucli cases the author should use his good judgment and make the best entry possible under the circumstances. For many spaces the correct entries represent the opinion of the author (for example, "Area Proved') and in such cases the entry need not be hedged to such extent as when the quantities are definite yet can be ascertained only approximately by the author. In cases under definite headings but where figures are only approximate, the author may use x. It is thought that the nearest whole numbers are sufficiently accurate for our purposes except as to percentage of sulphur in oil. If an author desires to report any other figures to tenths, he may do so. The quantity of gas produced should include, where possible, gas sold or otherwise marketed, and gas blown into the air, burned as flares or otherwise wasted. Segregation of these figures would be interesting if the authors can make such segregation. In any event, the figures should represent as nearly as possible the total quantity of gas removed from the reservoir. Under the columns on "Depth," the average depth to the top of the productive zones and to the bottom of the productive wells, when

Jan 1, 1941

By H. S. Drinker

THE first discovery of zinc 011 the property now worked by this company was made by the celebrated mineralogist, Prof. William Theodore Rapper, in 1845. Different claimants kept the property in continual litigation till 1861, when everything was satisfactorily settled by the purchase of the land by the company, who have worked it ever since. The mines are situated in a valley, four miles south of Bethlehem, Pa., in Lehigh County. The valley is from two to three miles broad, and is bounded 011 the north and south by syenitic hills. Syenite underlies the valley, and upon this is deposited the Potsdam sandstone, then a layer of slate, and, finally, a dolomitic limestone, belonging to the Chazy or Black River formation, in which the zinc deposits are inclosed. The rocks occur in folds, and have evidently been subjected to tremendous pressure from below, the zinc deposit being found in an anticlinal axis, in nearly vertical veins. I t is supposed that the zinc was originally disseminated through the

By E. R. Johnson

The copper concentrator of the Braden Copper Co. is at Sewell, Chile, on the westem flank of the main Cordillera of the Andes, at an air distance of approximately 50 miles southeast of Santiago, the capital of Chile. The region is mountainous and space is at a premium because of the rough terrain and the danger of snowslides. The ore, a porphyry copper, is mined by a block-caving method in the El Teniente mine. It is hauled to the crushing plant, a distance of 2.6 miles, through a tunnel because of the severe climatic conditions. The usual large, coarsely set, primary reduction machines found in many ore-treating plants are not required because of the mining method employed and the limiting 12-in. spacing of the grizzlies at the head of each ore pass in the mine. It is the purpose of this paper to describe the numerous improvements made in the crushing section of this large flotation concentrator during the past I5 years to increase the efficiency of the plant and to raise the daily output from around 20,000 to 30,000 tons. The reader should keep in mind that all changes were made within the existing building because of the limited space and the high cost of the heavy mill construction required to withstand the snow loads. The present plant, as well as the former, operates on a 24-hr, 7 days a week basis. The crushing plant commenced operations at its present site in 1921, the main equipment being No. 7½ gyratories, followed by 48-in. horizontal Symons disk crushers. Fines were removed by I-in. stationary grizzlies ahead of each unit. In 1924 a third stage of crushing was provided by the addition of 55½-in. rolls in open circuit. During 1925, the Symons disks were replaced by 73½-in. rolls. All the rolls were changed to closed circuit, with elevators and screens to give a final product of 9 pct plus 3-mesh. The flowsheet of a typical crushing section of this period is shown in Fig I. The ore was withdrawn from a common bill serving the five crushing sections in the plant by means of any number up to six 36-in. wide-apron feeders, which discharged onto a common conveyor belt. This conveyor was equipped with a magnetic head pulley and the crusher attendant was stationed near the discharge end to pick out pieces of mine timber that might be in the ore. The ore was discharged over a 13/4-in. spaced bar grizzly and the oversize of this grizzly was crushed by a No. 7½ McCully gyratory crusher set at 13/4-in. opening on the closed side. The grizzly undersize joined the gyratory discharge and was conveyed to a set of 73½ by 20-in. Garfield rolls set at I in. These rolls operated in closed circuit with a bucket elevator and two vibrating screens placed in parallel.

Jan 1, 1949

By L. E. Young

LOADING machines may be classified in several ways: (1) Machines which cut or break down and load .the coal; (2) machines which simply load the coal; (3) devices which load and transport the coal; (4) de-vices which elevate; (5) devices which transport the coal after it has been shoveled onto the device. There are many types of mechanical loading devices, Bull. 17, Coal Mining Investigations, under the auspices of Carnegie Institute' of Technology, U. S. Bureau of Mines, and the Advisory Board, listing 31 exclusive. of -the large shovels used in thick coal seams. Mechanical loading of coal is not in its infancy; I think some of the early patents go back to 1890. One large coal company, properly called the early leader in this field of mechani-zation, has about 26 large machines at work. This company spent about thirty years in developing a ma-chine, and at the present time is loading approximately two million tons of coal a year in its mines. The chair-man directed a question at the previous speaker; inquir-ing if real progress was being made in mechanical load-ing. The experience of the company just referred to is in itself an adequate answer. A review of a list of mines using mechanical loading devices shows that there are 28 mines which we may say are 100 per cent mechanical. There are four more mines which have been 100 per cent mechanical, but which are idle at this time on account of labor condi-tions. There are at least 25 more at which the tonnage is more than 50 per cent mechanical. In speaking of a 100 per cent mine I do not mean that every pit car of coal is loaded by machine, because when complete, re-covery of the coal is attempted it is not practical to load all the coal at, the break line. In order to load the last 5 to 10 per cent of coal with a minimum of gob material and in order to keep the. working places along the break line timbered in a safe manner it is generally desirable to use a few hand loaders. At a certain mine operat-ing on the block system 90 percent of the coal is being loaded by what is properly a mechanical loading: device, and about 10 per cent -is being loaded by hand. This 10 percent is right off the break line, out of what might be called, the screen pillar. The mines referred to are scattered over the country, . in seven different' States, and the equipment used is produced by ten different machinery companies. As to size, these mines vary from small mines of 500 tons mining capacity-up. In one instance a company with one loading machine is producing an, average of 450 tons per day. One of the large mines that is idle pro-duced at the. rate of 4300 tons per day, of which 97 per cent was actually loaded by machinery.

Jan 8, 1928

Jan 1, 1894

By James K. Stanley

WHEN a plastically deformed metal is heated to a certain temperature, it undergoes a complete change in microstructure, the consequence of which is a marked alteration of mechanical properties such as hardness, strength and ductility. This change in microstructure occurs by recrystallization and is a process involving the formation and growth of strain-free nuclei in the deformed matrix. These nuclei continue to form with time and grow until a new grain structure replaces the cold-worked structure. The formation of the nuclei in the deformed sheet of 1 per cent silicon ferrite is illustrated in Fig. 1. If a recrystallization is conducted isothermally, a measurement of the fraction of the matrix recrystallized plotted against time leads to an isothermal recrystallization curve, first established in 1942.1 Such recrystallization curves are shown in Fig. 4. These curves show that the recrystallization of a cold-worked metal is best considered as a rate process rather than a time independent process such as is suggested by the improperly named and misleading recrystallization diagrams involving deformation, temperature, and grain size. 2-5 Any study of the rate of recrystallization resolves itself into a study of the component rates of nucleation and growth. The previous paper' provided an account of the determination of the rates of nucleation; N, the number of nuclei formed per unit time per unit of unrecrystallized area, and growth, G, the radial growth in unit time, in the recrystallization of silicon ferrite (1 per cent Si). A method was developed to furnish experimental data for evaluating the effect of the recrystallization variables on N and G. The mathematical analysis for the derivation of the isothermal recrystallization curve was developed for a two-dimensional case (in thin sheets where the diameter of the recrystallized grain is greater than the sheet thickness). The present paper is a continuation of the study of recrystallization of 1 per cent silicon ferrite begun in 1942.1 In this work the effect of the factors deformation, temperature, grain size, composition, and recovery is studied with respect to the rates of nucleation and growth. At the same time it is shown how the cooperation of N and G affects the isothermal recrystallization curve. The study of these variables on N and G has a definite bearing on the mechanism of recrystallization and should lay a foundation for a rational theory on the subject. PROCEDURE The procedure used in these experiments was essentially the same as that described previously but in certain details some changes were made in the interests of speed. With few exceptions, the procedure is the same for the study of all the variables. Where the procedure is different from standard manipulations attention is called to this fact.

Jan 1, 1945

By Cyril Stanley Smith

The method of thermal analysis, so important in the development of metallographie science, has of recent years been falling into disuse owing to the development of other physical methods which give result's easier of interpretation and which can be used for the study of either equilibrium or transitional conditions because they do not require a continuously changing temperature. Nevertheless thermal analysis remains useful in the study of reactions that take place rapidly, and the simplicity of the experimental technique and the general availability of the apparatus involved are point's in its favor. Theoretically, thermal analysis is capable of giving specific and latent hat measurements and therefore should permit the study of reactions on a more fundamental basis than any other method. It is, however,difficult or impossible to obtain quantitative heat measurements from cooling curves obtained in the usual way. Even if the furnace containing the sample is cooled or heated at a linear rate, or if a gradient furnaec is employed to maintain a constant rate over a large range of temperature, the heat flow from or to the specimen depends on its previous history, for the difference of temperature between the specimen and its surroundings varies. The emissivity of the specimen surface, moreover, is unlikely to be constant. The able mathematical analysis by Russrll,1 although it prevent,s misinterpretat,ion of data, has an effect rather the reverse of that intended, and leaves the reader doubtful of the possibility of ever obtaining quantitative results from thermal curves. Nothing can be done to apply thermal analysis t'o the study of equilibrium conditions of reactions that arc not completed at rates of temperature change above about 1° C;. per minute, and this unfortunatetly excludes most solid transformations in alloys.† For the determination of liquidus

Jan 1, 1940