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By J. Wade Watkins, E. S. Mardock

The accurate evaluation of reservoir-performance characteristics in the secondary recovery of petroleum by water flooding requires use of a water tracer that may be injected into water-input wells and detected at oil-production wells to supplement data obtained from core analyses, wellhead tests, and subsurface measurements. Radioactive iodine has been used successfully as a water tracer in field tests to determine: (I) relative rates and patterns of flow of injected water between water-input and oil-production wells and (2) zones of excessive water entry into oil-production wells. Laboratory evaluations of potential water tracers, previous tracer studies, the value of using a radioactive tracer, general field procedures, and the use of surface and subsurface instruments for the detection of the emitted gamma radiation, are summarized. Data from the field tests are presented graphically and discussed in detail. It is concluded that the radioactive-tracer method, using radioactive iodine, may be used successfully to measure either the relative rates and patterns of flow or zones of excessive water entry into wells under conditions of comparatively rapid transit time between wells. INTRODUCTION Extensive use is made of data obtained from core analyses, wellhead tests, fluid characteristics, and subsurface measurements in evaluating the sweep efficiency of water injected into oil sands for the recovery of oil. Theoretical flow rates and patterns may be calculated from those data using radial-flow formulas, if it is assumed that the physical conditions in the productive formation are homogeneous. Unfortunately, homogeneous conditions rarely, if ever, exist in oil-productive formations. The use of a tracer that may be injected into an oil sand and detected quantitatively, or even qualitatively, at offsetting oil-production wells provides basic data that may be used in determining more accurately the subsurface rates and patterns of flow of injected water between wells than is possible by theoretical calculations based on assumed conditions. Consideration of the data obtained by using a water tracer assists in the application of remedial measures to water-input wells, such as plugging of channels, or selective plugging of highly permeable zones, thereby effecting a more uniform flood and a greater ultimate oil recovery. A water tracer should have the following characteristics: (1) low adsorption on solid reservoir material; (2) high solubility in water; (3) low or negligible solubility in crude petroleum; (4) a wide range of solubility of compounds that may be formed by chemical reactions with ions present in reservoir rocks or waters; (5) high detectability in low concentrations by portable apparatus; and (6) general availability at low cost. Additional desirable characteristics are that the tracer should be nonhazardous in nature under normal working conditions and quantitatively detectable in the well bore, as well as at the surface. Review of Previous Tracer Studies The need for a water tracer has been recognized for many years. As far back as 1906, Dole1 described the use of fluorescein in flow-rate studies made in France in 1901. In 1921, Ambrose" discussed in detail the use of organic and inorganic dyes, chlorides, nitrates, and other anions, lithium salts, and the Slichter electrical

Jan 1, 1955

By Karl F. Peterson, H. K. Najarian, Robert E. Lund

PRIMARY products of the Josephtown smelter are zinc metal of various grades, lead-free zinc oxide pigments, cadmium metal, and sulphuric acid. Zinc concentrates of domestic and foreign origin are blended and desulphurized at the roaster plant. The equipment includes five, 12-hearth Herreshoff roasters and two modified Trail-type suspension roasters. The sulphur dioxide containing gases from the roasting operation are diverted to a four-unit contact acid plant for the manufacture of sulphuric acid. The roasted calcines are agglomerated by sintering on Dwight-Lloyd-type sintering machines; the sinter is crushed and sized within required limits; and the sized sinter is smelted in vertical shaft-type electro-thermic furnaces. Of the 13 electrothermic furnaces of various sizes now in operation, four are designed to produce American process zinc oxidc of various specifications; and the remaining nine furnaces are equipped with vacuum-type condensers and produce zinc metal. Papers describing the general smelting practice at Josephtown have been published by AIME. Since both High Grade zinc metal and lead-free zinc oxide pigments are produced direct from the electrothermic furnaces without need for subsequent refining, the elimination of impurities such as lead and cadmium has to be accomplished during roasting and sintering operations. To effect the producing of both High Grade and Prime Western zinc products, the roasting and sintering operations are on two separate circuits. A High Grade circuit produces finished sized sinter low in lead, cadmium, etc., for the High Grade furnaces; and the Prime Western circuit produces finished sinter destined for the furnaces producing Prime Western metal. Sintering at the Josephtown smelter differs in many important respects from the sintering practice in smelters operating horizontal retort zinc furnaces. Requirements of the electrothermic smelting furnaces define the physical characteristics of the sinter, while the chemical composition of the sinter is controlled according to the grade of metal and oxide to be made as final products. Three principal objectives in the sintering process at Josephtown smelter are: 1. To transform the zinc calcine from the roasting operations into a hard, yet porous agglomerate that will not crumble in the smelting furnace. 2. Crushing and sizing of the sinter to obtain a proper screen analysis which is normally —% in. down to +1/4 in. particle size. 3. To eliminate, particularly in the High Grade circuit, as much of the impurities such as sulphur, lead, and cadmium as possible. The sintering plant as originally built in 1930 was equipped with three standard 42 in. x 44 ft Dwight-Lloyd sintering machines. Each machine was equipped with a 15x60 in. sintering corporation fan driven by 150 hp, 900 rpm synchronous motor through a magnetic clutch and capable of delivering 30,000 cfm of air at 15 in. of water and 150°F. Each sintering machine was driven by 7½ hp dc motor with controllers for varying the speed of the machine from 8 to 32 in. per min. The pallets were cast iron and the grates of the herringbone type. The charge was mixed in a 4 ft diam x 8 ft Stehli pugmill and transported by belt conveyor, elevator and tripper conveyor to a small bin over each machine. Shortly after the start of operations the following changes were found necessary: 1. The herringbone grates which plugged very quickly and were difficult to keep clean were replaced by straight, narrow cast-iron grate bars running at right angles to the travel of the pallets. These grate bars are held in place by a center bar extending across the pallet on the 24 in. dimension and by removable retaining plates which form the sides of the pallets. 2. Mechanical grate knockers were developed in conjunction with new grate bars for continuously and automatically cleaning the grates. 3. As the cast-iron pallets cracked, they were replaced with cast-steel pallets. In 1938, the capacity of the sinter plant was increased with the installation of two 42 in. x 22 ft machines which were brought from the company's Herculaneum lead smelter. With a circulating load of some 250 to 300 pct, production of finished sinter on the 42 in. x 44 ft machines at this time amounted to about three tons of sized sinter per machine hour. In 1945, one of the 42 in. x 22 ft machines was replaced by a 60 in. x 44 ft machine of our own design. In 1948, as part of the plant-wide expansion program, the sinter plant not only was expanded but also divided into two separate plants; namely, Prime Western and High Grade circuits. The sinter destined for furnaces producing Prime Western zinc metal is made in a new plant comprising two 60 in. x 44 ft Dwight-Lloyd-type sintering machines, each having a 45,000 cfm Sturtevant fan at 18 in. water static pressure and served by an 8 ft diam x 12 ft long rotary charge pclletizer and auxiliary crushing and sizing equipment. The sinter destined for furnaces producing High Grade zinc metal and zinc oxide pigments is produced in the old sinter plant which was expanded to accommodate four of the 60 in. x 44 ft sintering machines, replacing the old sintering units. In the High Grade sinter circuit, two units of the 60 in. x 44 ft machines are used as preliminary soft sinter machines; and the remaining two units of the 60 in. x 44 ft machines are used to make finished hard sinter. Purification Theory Partial elimination of lead and cadmium in the sintering of zinc ores is common knowledge. However, by some manipulation and by taking advantage of the double circuit, it is possible to make zinc sinter which is nearly free of contaminators. Lead

Jan 1, 1952

By R. P. Aikman, F. G. Miller, J. M. Podgursky

As part of a larger study of the mechanism of froth flotation of coal, the rates at which coal particles of various size and specific gravity react to froth flotation were investigated. Results of this study show that in flotation: I) recovery rate increases, but selectivity decreases with a decrease in particle size down to 100 mesh, and 2) recovery rate is constant for all sizes between 100M and 325M. n response to the growing demand for low-sulfur coking coal for iron making, the coal industry is continually striving to perfect methods for cleaning coal to acceptable ash and sulfur levels while maintaining maximum product yield. By present standards the industry has adequate processes for cleaning coarse coal, i.e., + 28 mesh, at almost any desired specific gravity. However, in the case of fine coal, i.e., —28 mesh, neither of the two existing processes - froth flotation or hydrocycloning — in its present state of development yields products that are comparable in ash and/or sulfur content to products normally obtained from coarse coal processes. The work outlined in this paper is part of a larger study directed toward maximum exploitation of froth flotation for fine coal processing. The concepts and data presented are now serving as a basis for designing fine-coal circuits in which improved efficiency is obtained by optimum use of froth flotation with other fine-coal processing methods. The paper includes: 1) A discussion of the value of a detailed wash-ability study as a method of assessing the problems associated with fine coal processing, 2) A general discussion of hydrocyclone principles, included to serve as a basis for understanding the mechanism of coal flotation, and 3) A detailed discussion of the mechanism of coal flotation, as well as the research leading to the optimum use of froth flotation in combination with other fine-coal cleaning methods to provide efficient fine-coal processing. Our study of the rates at which coal particles of various size and specific gravity react to flotation shows that in flotation: 1) recovery rate increases but selectivity decreases with a decrease in particle size down to 100 mesh, 2) recovery rate is constant for all sizes between 100 mesh and 325 mesh, and 3) the flotation process effectively rejects only those extremely fine particles which do not contain surface carbon. (Because of this feature, froth flotation is an excellent method for rejecting clays - the only extreme fines in - 325-mesh coal that are always carbon free.) Washability studies of flotation products are used to assess flotation efficiency. These studies show that: 1) the increase in percent sulfur in flotation products above the theoretical sulfur content as defined by the washability study is due almost entirely to flotation of fine high-specific-gravity particles that are part coal and part pyrite, and 2) in a given size range particle floatability decreases with an increase in particle specific gravity. Error curves are explained and are used to compare the mechanisms of coal flotation and hydrocycloning. These comparisons show that hydrocyclone performance is affected primarily by particle mass, i.e., particle specific gravity and size, whereas coal flotation performance is dependent on both the particle mass and the coal surface available for bubble attachment. Since the error curve is a basic tool for rating the efficiency of any coal processing system, it will be useful to quickly review the principles of error curve construction. RATING COAL-PROCESSING EFFICIENCY BY THE ERROR CURVE The organic component of coal is of lower specific gravity than its impurities, and the most effective principle for coal concentration is therefore separation on the basis of specific gravity. However, since there is no sharp dividing line between pure coal and pure ash components, specific gravity must be closely controlled if the product is to have acceptable quality at maximum yields. In turn, the basis for close control in any coal processing system is the reference standard provided by precise laboratory washability studies. In these studies, coal is carefully separated into a series of progressively higher specific gravity fractions to establish a relationship

Jan 1, 1968

Mineral Industries education as an entity, again and again has sought recognition, always to be turned aside or ignored.1 The incident mentioned in Lost Chapter was only the first of a series of disappointments. The Land-Grant Act is camouflaged here and there in the name of progressive education. A new interpretation may be in the best interests of society in so far as the goose is not killed that lays the golden egg. The primary objective of the act is still "agriculture and mechanic arts" but mechanic arts is not alone mechanical arts or engineering. Mechanic arts was used in a broad sense as a symbol of creative effort in locating and winning the fundamentals of existence - plants, animals, and minerals - from Mother Earth, their primary processing and treatment into foodstuffs and raw materials of industry, their manufacture into useful articles of commerce, and, last, their distribution and utilization. Significantly the great agricultural industry is now at least half mechanic arts. The Association of Land-Grant Colleges and Universities has neglected the mineral kingdom shamefully. The Association embraces Divisions of Agriculture, Arts and Sciences, Engineering, Home Economics, and Veterinary Medicine but has no division relating to the mineral industries.

Jan 1, 1950

By R. W. Raymond

The name of Oswald J. Heinrich first appears among the members of the Institute in the first volume of its Transactions, which records that lie was elected at the Boston meeting, in February, 1873. That name has stood ever since upon our catalogue of active members. It has appeared frequently in the reports of our debates. It has been attached to many interesting and important professional papers. Henceforward it must hold a place, silent but significant, ill the pathetic lengthening list of our departed. From a present

Jan 1, 1886

By Ernest E. Thurlow

The western coal industry, long overshadowed by the petroleum and metallic minerals industries, has been revitalized by several new coal mining operations, with the promise that this is only the beginning of a tremendous surge in production of coal that will carry into the next century. The content of this paper is confined to the coal fields and recent developments in eastern Montana, northeastern Wyoming and western North Dakota. The area is commonly referred to as the Powder River-Fort Union region although the Powder River Basin and the Fort Union formation are separate entities and are not coextensive. Coincidentally or otherwise, the extent of the subbituminous part of the coal region coincides approximately with the Powder River Basin. Environmental considerations together with the low sulfur content of much of the western coal have triggered demand since this coal could not compete at present with eastern and midwestern coal solely on a delivered-cost-per-million-btu basis. However, increasing costs of underground mining and the comparatively thin seams of the eastern and midwestern deposits may soon bring a balance to these costs regardless of the sulfur content. Another factor which has made western coal competitive at this time is the use of the unit-trains to significantly reduce the cost of transportation. Fast loading and unloading facilities and trains of 100 cars or more in turn-around service are the keys to success in this effort.

Jan 5, 1974

By D. S. Jacobus

The boiler here referred to was of the water-tube type, having 2535 square feet of heating-surface, which the makers held to be capable of generating 325 horse-power of steam; this being understood to mean that 325 times 30 pounds of water would be evap-

Jan 1, 1889

By Maurice Rey, H. Brevers

THROUGH circumstances connected with the war, the senior author lost his records therefore it has been impossible to include numerical data in this paper. The arsenical quicksilver ore investigated had been roasted, with poor metallurgical results. The vapor-tension temperature curves of mercury and arsenious trioxide are similar, and the arsenical compound hampers the coalescence of mercury drops in the condenser and is the cause of large stack losses. The ore was a gray limestone carrying small amounts of carbon and mineralized with cinnabar and two arsenic minerals, realgar (As2S2) and arsenopyrite (FeAsS). The proportion of realgar often exceeded that of cinnabar; the proportion of arsenopyrite was smaller. The grade of the ore varied between 0.8 and 4 per cent Hg. The problem was to make a high-grade mercury concentrate, as free from arsenic as possible. The water used throughout the testing was hard, having a pH- of about 8. FLOTATION OF REALGAR Realgar showed a very strong tendency to float. It formed a film at the surface of the pulp and floated in abundance with only pine oil. Therefore an attempt was made to float the realgar before the cinnabar, but this was not very successful; the percentage of mercury in the realgar concentrate could never be brought below 2 or 3 per cent. Cinnabar slimed easily and floated with pine oil, so that some of it always accompanied the realgar. There was also the question of the cinnabar-arsenopyrite separation. On further investigation it was found that realgar can be floated not only with pine oil but even better with a combination of hydrocarbons and pine oil. Washing the ore with ether revealed that it contained hydrocarbons, which helped to float the realgar. In this connection it belongs to the same class as carbon, sulphur and talc. It can be floated also with a xanthate, when activated by a heavy-metal salt. The conditions favoring the two types of flotation are opposed, as activation by a copper salt facilitates xanthate flotation (in fact, is even necessary to it), whereas it hinders pine oil and petroleum flotation. One type of flotation can be termed nonpolar and the other polar, a distinction that has been stressed in a previous paper. DEPRESSION OF REALGAR AND FLOTATION OF CINNABAR Many chemicals were tested in an attempt to float the cinnabar and depress the realgar. Finally starch rendered soluble with caustic soda was tried, also several grades of commercial soluble starch, and dextrin was found to be the best and the most convenient reagent. Several of these starch preparations have a strong flocculating effect on the pulp, which is a distinct disadvantage. Dextrin, with its low flocculating power, is excellent. It is noteworthy that starch preparations are also depressants for carbon and talc, so that the fact apparently has a general

Jan 1, 1941

By Helen L. Cannon

BOTANICAL methods of prospecting for metalliferous ores are based on the premise that deposits at depth may be reflected chemically in surface vegetation. For the past several years, on behalf of the Atomic Energy Commission, the U. S. Geological Survey has investigated on the Colorado Plateau the application of botanical methods to uranium prospecting. Results suggest that orebodies may be found under a considerable cover of barren sandstone through the absorption of uranium and associated trace elements by plants growing at the ground surface. Plant physiologists have demonstrated that uranium is a necessary nutrient for plant growth and therefore is present in all plants.' The amount present is small but measurable. The absorption of uranium by plants growing over ore deposits forms

Jan 1, 1955

By Reinhard Fischer

The consumption of lead for batteries in some western countries and Japan amounts to 870,000 T. annually. Battery life is 2-3 years. Therefore after a short time a considerable quantity of lead flows back to smelters. The production of lead from scrap batteries is discussed from the following points of view: 1. Separation of the acid contained in the batteries. 2. Separation of the components which are free of lead from the components containing lead, e.g. cases, separators. 3. Separation of metallic lead from lead compounds. 4. Avoidance of manual-work. A process has been developed and perfected at a plant, which began operation in 1965. The procedure consists essentially of the following steps: 1. Breaking the cases and removing the acid. 2. Crushing the batteries in an impact mill. 3. Screening off separators. 4. Separation of slurry. 5. Gravity separation of metal and organic material. The plant has a one-shift capacity of -24,000 T. batteries/year.

Jan 1, 1970

By R. E. Head

SOME mixtures of sulphide and oxide ores from the Tintic district in Utah are of a sufficiently good grade to be shipped to the smelter without beneficiation. In mining this type of ore, however, a material tonnage of ore of a similar composition but of lower grade is obtained. It is a ques-tion of economics whether such ore should be shipped with a certainty of a small return or concentrated if that would yield a sufficiently increased return to amortize plant construction and upkeep and yield a higher rate of profit than at present. It may be assumed that the tonnage of this borderline ore is constantly increasing and that eventually it will, attain such proportions as to justify plans for milling on a relatively large scale. Under existing conditions, the producer of mixed sulphide and oxide ores is not greatly concerned about the physical characteristics of his ore or of its mineralogical complexities, since his contract with the smelter calls for payment on the basis of chemical analysis. When concentration is contemplated an entirely different picture is presented. Percentages of valuable metal content must then be con-sidered in terms of minerals, for it is in the form of minerals that recoveries are made and losses sustained. In describing the performance of a given flotation mill and reagent combination, it may be stated as a generality that a specific percentage recovery of valuable elements is made. Tech-nically, however, the concentrator is really constructed and the reagents are selected to recover the valuable minerals. These considerations must be given prominence in discussing border-line ores from the Tintic district because of their physical characteristics and mineralogical composition. Because of these peculiarities they may be justly termed complex, since their lead, silver, and copper contents are each represented by two or more minerals of different chemical composi-tion and presenting widely divergent physical properties. This paper sets forth the results of a microscopic study of a type of borderline ore from the Tintic district that is now being treated by direct smelting. A

Jan 1, 1938

By D. L., Hayes

THE concentration of zinc ore in Wisconsin is a comparatively simple process, although it presents problems that must be overcome in an efficient manner in such a way that installation and operating costs are low. As the ore deposits are small, the first cost of the concentrating plant must be low; while the low margin of profit makes it necessary to have the minimum operating costs. The original mills were copied from those of the Joplin district, as most of them were built and operated by Joplin millmen. These served the purpose well; they made a clean concentrate, which was the chief requirement at that time, as most 'of the mines were' considerably 'richer than the average at the present time, and wages and supplies were also considerably lower. ' The apparatus used at present has changed very little in principle. . The grizzly opening has gradually been increased to 12 in. and sometimes no grizzly 'is used. The crusher, gradually grew in size, the largest crusher has -an opening of about 24 by 13 in. and a 7/8-in. throw on the. eccentric shaft.

Jan 1, 1921

YEAR OF ELECTION 1913. FRANK DAWSON ADAMS, Montreal, Canada. 1933. KARL EIKERS New York, N. Y. 1922. FEDERICO GIOLITTI Torino, Italy. 1906. SIR ROBERT A. HADFIELD London, England. 1921. FRANK WILLIAM HARBORD London, England. 1917. HERBERT HOOVER Washington, D. C. 1941. DANIEL COWAN JACKLING San Francisco, Calif. 1939. HENRY KRUMB New York, N. Y. 1921. C. McDERMID London, England. 1913. EZEQUIEL ORDONEZ Mexico City, Mexico. 1935. ROBERT PEELE New York, N. Y. 1938. A.M. PORTEVIN Paris France 1937. JOHN V.W. REYNDERS, New York, N. Y. 1937. GEORGE S. RICE Washington, D. C. 1911. ROBERT H. RICHARDS Cambridge, Mass. 1934. T.A. RICKARD Victoria, B.C., Canada

Jan 1, 1941

By Robert Glass Cleland

WALTER DOUGLAS succeeded his father, Dr. James Douglas, as president of Phelps Dodge in 1916. Before assuming office, the new president had been assayer at Bisbee, superintendent of the Copper Queen, general manager of all the Phelps Dodge mining interests, and altogether had spent a full quarter of a century in various phases of the company's business. Energetic and imaginative, experienced and courageous, he had need of all these qualities before he surrendered the direction of affairs into younger hands, fourteen years later. For the period of his administration was one of sudden ebb apd flow, flush production, drastic curtailment, quick recovery, and near-disaster. In 1917, soon after Walter Douglas became president, Phelps, Dodge & Co., Inc., which had been formed in 1908 as a holding company, went through an internal reorganization for the purpose of simplifying the structure and changing it from a holding company to an operating company. The Copper Queen Consolidated Mining Company, which had the necessary charter power and authority to carry on the business of any and all the subsidiary com-

Jan 1, 1952

By Frank Firmstone

IN the summer of 1881 we were forced to break up and remove the large mass of iron which had accumulated under No. 2 furnace at Glendon, in order to prepare the foundations of the new furnace which has taken its place. We used "Atlas" powder, drilling the holes with a pair of Rand drills. These worked very well when the iron was at all uniform in hardness; but this was not often the case; and it frequently happened that the holes were hopelessly blocked when but little over a foot deep. Good tamping became, therefore very important. The common method of tamping is certainly very dangerous when there is a percussion cap in the hole, and has, no doubt, caused many of the accidents attributed directly to high explosives. We found an excellent and safe method by using plaster of Paris, mixed to the proper consistency and ponred into the holes as soon as they were loaded. Clean dry sand was mixed with the plaster to reduce the quantity needed. With proper attention the tamping would set in a few minutes, and little or no more time was required than for tamping in the ordinary way. We used a "magneto" machine (Laflin and Rand) to fire the holes; and an additiollal advantage in the plan was that any risk of cutting the exploder-wires in tamping was avoided. We found it worth while to load holes not over 13 inches deep in a block 3 or 4 feet thick since the bottom of the hole was enlarged by each shot so that the next time it could be loaded more heavily, and three or four shots in this way often did as much good as a new hole twice the depth, to drill which might have taken ten or twelve hours. The rise in temperature when boiled plaster solidifies is not sufficient to ignite the exploders, as we found by repeated trials before using it in a loaded hole.

Jan 1, 1884

By Laurence W. Casteel

Indian Creek Mine, newest of the St. Joseph Lead Co. properties, is located in southeast Missouri on the flanks of a buried porphyry ridge. Here the orebodies are very irregular in size and shape and have a regional pitch of about 15°, which may vary locally from 0 to 90°. To maintain an economical grade of ore, selective mining is imperative. The room and casual pillar method is employed with 20-ft diam pillars 35 ft apart where possible. Stopes vary in height from 10 to 55 ft. All are too small to supply a loading unit continuously.

Dec 1, 1956

By J. D. Vincent

During the history of man, the term concentration has had many meanings. Early in history, it may have been construed to mean sorting and smelting. Not many years ago, its definition included only the physical beneficiation processes. Today, and in this article, the term concentration is taking on the meaning of beneficiation and chemical processing, or either separately. An alternate definition could be: concentration is the process of recovering and upgrading an element or nonmetallic mineral so that the product can be used or refined for the needs of man. For the purpose of this article, concentration will have the same connotation as it does in the mineral industry, which has come to include processing methods such as leaching and chlorinization under this heading. Usually, smelting techniques and electrorefining are excluded and classified under the heading of refining. Using the broad definition of concentration, the areas of mining processing include not only the physical beneficiation processes and flotation but also hydrometallurgy and vapor-metallurgy. These methods include sorting, sizing, crushing and grinding, gravity concentrating, magnetic processing and flotation as well as hydrometallurgy and vapor- metallurgical processing.

Jan 1, 1971

By Zdzislaw Specht

This paper discusses elementary laws pertaining to seismic reflection methods and presents a general and simple criterion for determining the direction of dipping of a reflection horizon from observational data of distance and time. The important development of practical geophysics and the successful results obtained in America, Germany, and other countries, caused introduction of geophysical methods of prospecting in Poland. Of all methods, seismic prospecting has proved most successful in the area of the Carpathian foreland, where new oil reserves are to be expected. Because of the great depth of the sedimentary column in that area, ranging sometimes over 2000 meters, it was obvious that only the seismic reflection method could give reliable information regarding the structural features of these strata at such a depth. During the experimental surveys it appeared that the complicated geological conditions of that area do not always allow prediction of the depth and the angle of dipping of reflecting horizons, and for that reason information about the inclination of a given horizon has great importance in the determination of subsurface structure. Therefore the problem arises of obtaining from seismic reflection data reliable information as to the direction of dipping of reflecting strata, without any previous knowledge of the average velocity and depth of geologic horizons under consideration. Reflection Seismograms The earth, being a nonhomogeneous medium, is composed of a series of layers, which differ from each other in their physical properties, particularly in their elastic coefficients. These variations in elasticity are the cause of refraction and reflection of a seismic wave. Under the simple but only approximately correct assumption of the straight-line path or an elementary elastic disturbance, the phenomena mentioned

Jan 1, 1940

By Zdzislaw Specht

This paper discusses elementary laws pertaining to seismic reflection methods and presents a general and simple criterion for determining the direction of dipping of a reflection horizon from observational data of distance and time. The important development of practical geophysics and the successful results obtained in America, Germany, and other countries, caused introduction of geophysical methods of prospecting in Poland. Of all methods, seismic prospecting has proved most successful in the area of the Carpathian foreland, where new oil reserves are to be expected. Because of the great depth of the sedimentary column in that area, ranging sometimes over 2000 meters, it was obvious that only the seismic reflection method could give reliable information regarding the structural features of these strata at such a depth. During the experimental surveys it appeared that the complicated geological conditions of that area do not always allow prediction of the depth and the angle of dipping of reflecting horizons, and for that reason information about the inclination of a given horizon has great importance in the determination of subsurface structure. Therefore the problem arises of obtaining from seismic reflection data reliable information as to the direction of dipping of reflecting strata, without any previous knowledge of the average velocity and depth of geologic horizons under consideration. Reflection Seismograms The earth, being a nonhomogeneous medium, is composed of a series of layers, which differ from each other in their physical properties, particularly in their elastic coefficients. These variations in elasticity are the cause of refraction and reflection of a seismic wave. Under the simple but only approximately correct assumption of the straight-line path or an elementary elastic disturbance, the phenomena mentioned

Jan 1, 1940

(Members are urged to send in for this column any notes of. interest concerning themselves or their. fellow-members.) Members and guests who registered at Institute headquarters during the period July 10 to Aug. 10, 1914: W. B. Foote, Geneva, N. Y. John T. Beard, Temascaltepec, Mexico. E. J. Carlyle, Perm, Russia. F. H. Jackson, Alum Rock, Pa.. H. H. Bradt, Pittsburg, Pa. M. F. Sayre, Schenectady, N. Y. Dwight Furness, Guanajuato, Mexico. Prof. Robert H. Richards, past-president of the Institute, has retired as head of the Mining department of Massachusetts Institute of Technology and will engage more actively than formerly as consulting engineer in ore-dressing problems. Luther W. Kemp, who has been Metallurgist of the North Star Mines Co. at Grass Valley, Cal., has resigned to accept a position in Chile,. S. A.

Jan 9, 1914