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By Iley B. Browning, R. E. Strouder, Coleman D. Hunter, Ralph N. Thomas, George M. Straughan

Activity in the oil fields of the state was at a low ebb during the year because of the longest period of low prices that has yet prevailed, which has been detrimental to both the eastern and western sections of the state. Production for the state as a whole shows a drop of 209,192 bbl. during 1939, the total being 5,356,963 bbl. The loss is in the production of the western division, where a loss of approximately 300,000 bbl. more than offset a gain of approximately 100,000 bbl. in the eastern division. The loss in the western division can be attributed to decline in drilling activity due to the low prices prevailing, which were caused by flooding of the normal markcts with cheap Illinois crude. The gain in the eastern division is the result of repressuring operations begun in previous years and now showing results, and not to any renewed drilling activity. Gas development in western Kentucky during 1939 was of minor importance. In eastern Kentucky approximately 50 producing gas wells were drilled, which were sufficient for present market with excess reserves already developed. With the severe winter and additional industry load every gas well connected has been on line for the past three months. Although all demands are being met, development will be greatly increased during 1940 to meet depletion. From the geological point of view, the drilling activity in the western division developed additional information of benefit. Several wells on blocks of acreage assembled in previous years were drilled in the deeper parts of the Western Coal Basin—southern part of the Illinois Basin— giving for the first time accurate information about the Pennsylvanian and lower formations down to and through the Devonian.

Jan 1, 1940

By Willard H. Tracy

The method of seismic reflection prospecting has many times been compared to sound ranging, a process that became familiar to many during the World War. According to this very simple theory, the dynamite goes off and sends out a compression wave, which meets a reflecting horizon and returns to the surface, where it is recorded and the elapsed time of its travel in the earth accurately determined. Computations are then made on the general theory that the longer the elapsed time, the greater the depth of the reflecting bed. While this serves to give an idea of the fundamental basis of the process, it suggests a simplicity that does not exist in the life history of the various waves set up by a dynamite explosion in the earth. To begin with, a seismic wave in the earth does not obey the same simple laws of propagation that apply to a sound wave in the air. The property of strength in shear possessed by solids introduces a factor that sets such waves apart from the ordinary air waves. Also, the transmission charactcristics of the earth vary widely from place to place, and a fairly accurate knowledge of the space relationships of these variations is necessary if the final results are to be understood. Besides the waves recorded and used in the reflection computations, there are many

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

By D. A Dahlstrom

THE necessity for slime elimination from valuable mineral and coal products has become increasingly significant within the past 5 years.' , Most of the mechanized mining and present beneficiation methods have resulted in larger tonnages of extreme fines, silts, and clay, commonly called slimes, processed by the preparation plant. Economics in turn have forced the plant operator constantly to lower the bottom size of effective beneficiation, necessitating an almost complete recovery of valuable solids regardless of particle size. When these important factors are considered, the need for an efficient slime removal method for fine solids becomes self-evident. Ordinarily slimes have been classified as ranging from 75 microns, or 200 mesh, down to colloidal dimensions of less than one micron. At the same time there is general agreement that the most troublesome slimes are primarily clays, silts and extreme fines, so that the actual top size may be placed at approximately 30 to 40 microns. This immediately restricts any desliming operation to classification, as screening or other methods would be both uneconomical and grossly inefficient at such dimensions. The liquid-solid cyclone has been recognized as one of the most efficient fine size classifiers available to the mining industry. Applications of cyclones to thickening, high efficiency solid recovery, degritting,

Jan 1, 1953

By Ralph Sweetser

THE present state of iron blast-furnace practice is metallurgical rather than mechanical; the tend-ency is toward intensity rather than toward ex-tension. The engineers have built blast furnaces big enough and strong enough, and have furnished accessory equipment ample and accurate enough for the present state of the art, but the metallurgical side has been too much neglected; the metallurgist, rather than the engi-neer, is now the man on whom the present and future progress in iron blast-furnace practice depends. The mining engineer has produced great tonnages of iron ores, and has kept ahead of the demands for quantity; now the metallurgist is improving the chemical and physical qualities of this product by ore-dressing and other forms of beneficiation. For a generation or more, the principles of mechanics have had most influence in the advancement of iron blast-furnace practice; atten-tion now is given more to the principles of metallurgy, chemistry, and ore-dressing. This metallurgical progress is taking place inside and outside the blast furnace. The two great determining factors of the inside operation are the slag, and the rate of combustibility of the coke. Outside the fur-nace, the progress is, and will be, along the lines of more careful mixing of ores and iron-bearing materials, in the sizing and washing of limestone, and in the char-acter and structure of byproduct coke.

Jan 3, 1922

By W. L. Dudley

It is my desire to call attention to a new industry which was started about four years ago, through the discovery by Mr. John Holland, a resident of this city, of the methods employed in working the metal iridium. This metal has been known since the year 1803, having been discovered by Smithson Tennant while investigating the metallic residue which remained when platinum ores were dissolved in aqua regia. The metal is classed among the rare metals, as it is not found in large quantities, although it is quite widely distributed geographically. It is found in California, Oregon, Russia, East India, Borneo, South America, Canada, Australia, and in certain parts of France, Germany, and Spain. The principal sources of supply of the metal are Russia and California; it is nearly always found with either platinum or gold, is extracted from those ores as a by-product, and is always found in small grains or fine powder, the largest pieces being about the size of a grain of rice. In nature it is generally alloyed with other metals, and the two metals with which it is most commonly alloyed are platinum and osmium; the platinum alloy is called platin-iridium, and the osmium alloy osmiridium, or iridosmine. The grains of platin-iridium are

Jan 1, 1884

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 Alden B. Greninger

THE time-honored description of the growth of metal crystals to form polycrystalline aggregates is. one in which two important steps are considered: (1) nucleation, and (2) dendritic growth, each dendrite starting from its individual nucleus and resulting (upon slow cooling, assuming no solid phase changes) in a macrograin. This picture of the process of crystallization is incomplete, and it is with the hope of enlarging upon it that the following summary and correlation of experimental results are given. MOSAIC STRUCTURE For an exact definition of the mosaic structure of metal crystals-if, indeed, one can be found that will hold for all metals-one must await the results of much experimental work in this field. The writer's investigations have been. confined almost entirely to copper and a few of its alloys. The following terms are proposed, and will be used in this report: Macromosaic Structure1.-Large-scale mosaic structure; more specifically, mosaic structure of a scale large enough to produce splitting of Laue spots on back-reflection Lane X-ray patterns2. The deviation from exact parallelism of neighboring macromosaics varies from a few

Jan 1, 1935

By Otto F. Pfordte

The great advance of the last twenty years in the specialization, delicacy and efficiency of ore-concentrating apparatus calls for a finer system of testing both the qualities of ores and the operations of machines in this department. In amalgamation, lixiviation and smelting, the daily employment of physical and chemical tests has been recognized as necessary, and the cost of the necessary laboratories and employees is cheerfully paid. But while much progress has been made in concentration (due, in a large degree, to the study of the subject in our technical schools), it is still too common in actual practice to follow the loose old method of roughly estimating, once for all, that a given ore " concentrates x tons into one," and resting on this assumption so long as that ore continues to be treated, while assays of the tailings from concentration are made from time to time, without exact determination of their quantity. The first step toward accuracy of control must be a more frequent and precise measurement of the quantity of concentrates from a given operation. This should be expressed in pounds per unit of one ton; and the variations shown in frequent determinations will furnish a constant check upon the character of the ore and the performance of the apparatus. But this is only a part of what should be constantly and systematically done to insure the best work upon a material which must vary continually, even though it come from one mine only. If, in any mill, appropriate laboratory-tests were made at least once a week, the labor and expense involved would be amply repaid by increased knowledge and control of the current operations. A small testing-laboratory, provided with a few gold-pans;

Jan 1, 1902

By Campbell Osborn

FROM the viewpoint of practical economic engineering the main value in studies of demand and supply lies in the information they give concerning the next movement of price. The title of this discussion is too comprehensive for detailed analysis and it will, therefore, be narrowed to the question of price measurement. The oil operator is interested primarily in net profits. Prices, costs and production determine them. Production is here used in its broadest sense. It includes refining and marketing. It is an operating problem. Prices and costs are economic considerations. Though costs are an important element of prices and profits, the subject is too large to be treated in a brief paper of this sort. In the long run, costs govern prices, but for the purpose of gaging prices in the immediate future the relationship of current demand and supply are more significant. Operating, expansion, retrenchment, sales and storage policies of oil companies are largely influenced by the feeling of executives concerning this relationship. The stockholders of companies whose executives are wrong may suffer. Investors who err in their judgment may likewise lose. On the other hand, oil companies and investors who appraise these factors correctly and move accordingly will profit. It is an important subject worthy of careful consideration.

Jan 1, 1928

By A. B. Parsons

This YEAR BOOK, which is sent to every member, contains the roster of officers and the principal standing committees, brief summaries of the proceedings of the Annual Meeting and of the regional and divisional meetings, abstracts of papers published during-the-year, and a classified list of TECHNICAL PUBLICATIONS and CONTRIBUTIONS, as well as an index of all material published by the Institute in 1935 in these separate forms, in TRANSACTIONS and In MINING AND METALLURGY, the monthly magazine. The two volumes published for the Seeley W. Mudd Memorial Fund are also represented by many items in the index. The necrology, which has appeared in the YEAR BOOK for two years past, will be pub¬lished in the. DIRECTORY, in the spring of 1936. Four volumes, 114 through 117, of the TRANSACTIONS are 1935 publications,-the subjects being, in the order named, Petroleum Development and Technology, Mining Geology, Iron and Steel, Founding and Metallography of Nonferrous Metals (Institute of Metals Division). The Mine Plant volume, which was authorized for publication by the Rocky Mountain Fund, and which was offered as an alternative to a TRANSACTIONS volume, was unavoidably delayed. It will, however, be published as a 1935 volume, and will be distributed as early as possible in 1936. The sixth volume in the A.I.M.E. Series, published under the auspices of the Seeley W. Mudd Memorial Fund, is Coal through the Ages, by. Howard N. Eavenson; the seventh, Modern Uses of Nonferrous Metals,. which has twenty-two authors and was edited by Dr. C. H. Mathewson. Also, it was necessary in 1935 to have a second printing of the first Rocky Mountain Fund volumes, published in 1933-The Porphyry Coppers, and .Ore Deposits of the Western States (Lindgren Volume). The papers for the Iron and Steel and Institute of Metals Divisions have been issued as TECHNICAL PUBLICATIONS distributed under the binding Of METALS TECHNOLOGY in the months of January, February, April, June, August, September, October, December. This plan of distribution will be continued in 1936 for these two groups.

Jan 1, 1936

By L. D. Godshall

The extreme difficulty of obtaining a short and, at the same time, exact method for the determination of gold and silver in copper-materials has been well illustrated in "Assays of Copper and Copper-Matte," and its discussion, by Dr. A. R. Ledoux and other leading authorities on this subject.* Two general methods were used by the numerous assayers who took part in the symposium initiated by Dr. Ledoux, and whose results are given in the paper and discussion. One of these is the dry or fire-method, consisting of scorification and cupellation, the former being repeated if the percentage of copper is very high, all slags and cupels being assayed and the results so obtained added to the ordinary assay; and the copper retained by the silver buttons being determined and deducted from the combined weight of the buttons obtained from the assay of the original material, the scorification-slag, and the cupel. The other is the wet or combination-method, which, while not involving so much work, requires a longer time. Briefly, it is as follows : The material to be assayed is dissolved in nitric acid, the solution is diluted, and the fine undissolved gold is collected by means of sulphate of lead, formed by the addition of lend acetate and sulphuric acid to the solution, After standing from 12 to 24 hours, the precipitate is filtered off, and the silver in the filtrate is precipitated as a chloride or bromide, and collected by means of sulphate or bromide of lead. The solution containing this precipitate in suspension is again allowed to stand until the precipitate has settled. It is then filtered; both precipitates, containing the gold and silver, are dried, ignited and scorified, either separately or together, and the result is cupelled in the usual way.

Jan 1, 1901

By John C. Branner

Five of the geologic horizons that yield oil in other parts of the world are represented in Brazil; namely, the Devonian, Carboniferous, Permian, Cretaceous, and Tertiary. Thus far, the first two have shown no evidences of being oil bearing within Brazilian territory. Not enough exploring has been done to permit trustworthy comparisons of the relative importance of the Permian, Cretaceous, and Tertiary as oil-bearing horizons in this country. The most important, indeed almost the only, information available relates to the locations of the areas and to the structural features of the several horizons. The theories regarding the physical conditions under which these rocks were laid down, however, I regard of the utmost importance. Permian Rocks of Permian age cover an enormous area in Brazil, extending from Rio Grande do Sul to Maranhao on the north, and to Matto Grosso on the west. These Permian rocks in many places are known to include oil-bearing shales and in some locations contain small veins of gilsonite. The geologic map of Brazil shows that the Permian area is widely distributed, but there is considerable doubt about the origin of some of the rocks. Some of the lower Permian beds in southern Brazil contain marine fossils, but in Minas no fossils have as yet been found in them, and in Bahia, at only one locality have a few Permian plants been found. Indications of oil have been found in the states of Sa0 Paulo, Parana, and elsewhere farther south, but wells drilled in the Permian of SaO Paulo near the Morro do Bofete did not find oil. One well has been started, by the Brazilian Government, in the Permian of Parana near Marechal Mallet, close to latitude 26" south, but thus far oil has not been found.

Jan 1, 1923

By Arthur Taggart

IN 1900, Elmore found that if an acidulated pulp was stirred up with an oil which was relatively insoluble in and lighter than water, and the mixture was al-lowed to stratify, much of the sulfide would be found hanging to the lower surface of the floating body of oil and could be skimmed off or overflowed with it. The action of the flotation agent here is two-fold, first to select the sulfide from the gangue-what to-day is called collection-and second, to buoy the col-lected sulfide away from the gangue. The action in collecting is illustrated by Fig. 1, which contrasts the behavior of drops of oil brought, under water, to the surfaces of gangue and sulfide particles, respectively. The oil displaces water from the surface of the sulfide; the water displaces oil from the gangue surface. If, instead of considering the solid particles the fixed parts of the system of oil, water and solids, we consider the oil and water fixed and the solids pre-sented to the surface of contact, the condition will be as shown in Fig. 2 ; the sulfide tends to be drawn into the interface and the gangue to be excluded. The sul-fide particles are held in the oil-water surface by the tension of this surface. The buoyant effect is supplied by the oil droplets in bringing the sulfides to the water surface, but not in holding them there.

Jan 6, 1928

By Bernard Schneider

The diversity of methods available to engineers and geologists for studying rock masses is a reflection of the fact that, despite the rapid and encouraging progress made over the last few years, there is still no unified and comprehensive method which can be used to predict the over- all behavior of a foundation. Nevertheless, it is agreed that the fundamental characteristic affecting the engineering properties of rock is fissuration, and this paper de- scribes a few new or improved methods of studying fissuration and its influence on major engineering factors such as permeability, deformability, or internal stresses in the rock volume. TESTS ON SAMPLES Conventional tests on samples using thin slices can be improved by staining the slices before cutting with certain ionic dyes which have an affinity for certain types of surface. This shows up the microdiscontinuities. For example (quoted terms are French trade names) : "Turquoise Motylhne JSA" will show up porous alteration of basic feldspars. "Vert brillant SA" is used for acid feldspars. "Fushine ASA" will show up voids in all rocks. A mixture of "Turquoise" and "Rhodamine BSA" will show up zones of alteration in all types of feldspars. With this technique, it is easy to make an optical classification of the different structural types, e.g.: (1) rocks completely free from voids; (2) rocks with microfissures, which in turn can be subdivided into (a) rocks with microfissures secant to the mineral structure, (b) rocks with microfissures parallel to the mineral structure, and (c) rocks with ran-

Jan 1, 1970

By W. J. Schuster

*Original Pages Missing From Book HANNA COAL CO., Division of Pittsburgh Consolidation Coal Co., operates three large under- ground mines in eastern Ohio. The section of Pitts- burgh No. 8 coal seam in which these mines are located varies in thickness from 52 to 64 in. It is immediately overlain by a stratum of shaly material 12 to 15 in. thick locally known as draw slate, which is structurally very weak and which disintegrates rapidly upon exposure to atmosphere. Immediately above the draw slate as it is normally found is a band of extremely high ash material 6 to 12 in. thick known as roof coal or rooster coal, and above this is a stratum of conglomerate material varying from 4 to 10 ft in depth. Overlying the conglomerate is' a relatively thick stratum of limestone, the first stable material above the Pittsburgh coal seam in eastern Ohio. With the method of full-seam mining that has been adopted, draw slate is shot down, loaded with the coal, and removed in the preparation plants. The roof coal then becomes the permanent roof. The major problem in mining the No. 8 seam in eastern Ohio is control of the roof. Since the strata above the draw slate contains no material with a structure firm enough to provide self-support, the roof begins to sag in a relatively short time after the coal and draw slate have been removed. The problem thus becomes one of getting temporary safety posts under this roof as quickly as possible to prevent a break or separation from occurring either in the roof coal or in the conglomerate above it.

Jan 5, 1954

By O. A. Knight

THE suppression of the austenite-martensite transformation that can be brought about by the addition of certain alloying elements, such as manganese or nickel, to plain carbon steel has been known for a long time, especially since Guillet's investigation at the beginning of this century. The extent to which the critical range is lowered depends upon the percentage and nature of the special element added. First the Ar1 point is lowered gradually, then at a certain percentage a sudden lowering to about 300° C. occurs. The addition of still larger percentages of the alloy may result in lowering the Ar1 point to room temperature or below, in which case the steel remains austenitic at room temperature, especially after rapid cooling. The effect of alloying elements of this general type on the lowering of the transformation temperature is well illustrated by Sauveur(1)§ in his Fig. 281a, reproduced here as Fig. 1. This type of curve is characteristic of both manganese and nickel though it requires about 2 1/2 times as much nickel as of manganese to produce the same result. The influence of nickel in retarding the transformation of austenite into the lower transition constituents is due to its lowering of the critical range of the steel, which is also well illustrated by Sauveur(1) (after Osmond) in his Fig. 284, reproduced here as Fig. 2. Scott(15) presents a diagram illustrating the effect of manganese on the Ac3 and Ar3 points which is strikingly similar to the diagram above referred to in Fig. 2 concerning the effect of nickel.

Jan 1, 1934

By J. Chipman, J. A. Cordier

Equilibrium in the reaction H2 (g) + 2 = H2S (g) was studied at 1600°C for sulphur dissolved in Fe-Ni alloys of 0 to 100 pct Ni. Within experimental accuracy, the equilibrium ratio pH2s/pH2 [pct S] is independent of the Fe-Ni ratio. Its variation with sulphur content is the same in nickel and the alloys as in iron. Recent data on dissociation of S2 into atomic sulphur are used to apply a small correction to earlier equilibrium data. Equations are presented which define the thermodynamic properties of sulphur in liquid Fe-Ni alloys. ACTIVITY of sulphur in liquid iron was determined by Sherman, Elvander, and Chipman.' The effects of a number of alloying elements on the activity of sulphur also have been determined, that of silicon by Morris and Williams,2 that of carbon by Morris and Buehl,8 and the effects of manganese, phosphorus, and aluminum by Sherman and Chip-man.' The data of Rosenqvist and Cox5 have been used to establish the effect of copper. A summary of all of these data is included in the paper by Sherman and Chipman. In each case, the experimental method depended upon the study of equilibruim in the reaction of sulphur in the liquid metal with hydrogen gas to form H,S. Despite wide differences in the design of apparatus used by the several investigators, all of the results are in excellent agreement. Experimental Study Since the experimental method has already been described,' it will be sufficient to mention its general

Jan 1, 1956

By W. J. Keep, Edward Orton

During the past two or three years consumers of pig-iron have been seeking more knowledge regarding the chemical questions involved in foundry-practice. This desire has been increased by the papers of Professor Thomas Turner, of Mason College, Birmingham, reporting a series of tests made to show that silicon is a useful, rather than a damaging element when present in proper quantities in cast iron, and that by its use pig-irons and scrap, which when used alone are totally unfit for foundry purposes, may be made to give satisfactory results. Professor Turner has shown that the strength of a cast-iron depends on : 1. The amount of weakening impurities present; 2. The proportion existing between the combined and the graphitic carbon in the cast-iron. He says that the tendency of combined carbon is to increase hardness and brittleness, while graphitic carbon makes iron soft, malleable and tough; too much of either form is a disadvantage; the strength depends on the proportion. Strength being the thing most desired, irons having an excess of weakening impurities will not find a market, and therefore the only thing to provide for is the proper proportion between combined and graphitic carbon. Professor Turner shows that by a judicious use of silicon this proportioning can be accomplished exactly according to the wish of the founder; an increase of silicon changing combined carbon to graphitic, and vice versa. When the founder understands its use he may soften and toughen, or harden and strengthen his

Jan 1, 1889

By O. B. Hopkins

Essentially all production for Peru came from the three established fields in coastal northwestern Peru (Fig. 1). These fields are known as La Brea-Parinas, Lobitos, and Zorritos, in order of importance. Together they produced 13,496,880 bbl., as compared with 15,838,605 bbl. in 1938. Zorritos Field.—Of the total production shown on Table 1, the Zorritos field was responsible for a relatively negligible amount estimated at 40,000 bbl. This small field, which is over 50 years old, was purchased by the Peruvian Government in the spring of 1939 from the Piaggio interests. The Government operated this field along with its near-by National Reserve areas, largely under supervision of Department of Mines officials, and the total production rate for both old and newa-areas was estimated to have increased by Oct. 1 to 166 bbl. per day. as compared with the 1938 average of 110 bbl. per day. Construction is said to have begun on a refinery that is to have a capacity of 1000 bbl. per day and is to include a gasoline-extraction plant, and on a pipe line to bring fresh water 20 miles from the Tumbes River. Lobitos Fields.—The Lobitos fields, some 70 miles south of Zorritos, produced approximately 2,650,000 bbl., or almost the same amount a* in 1938. La Brea-Parinas.—The International's La Brea-Parinas property, immediately south of the Lobitos property, produced 10,806,880 bbl., or 80 per cent of Peru's production. During the year 73 wells were drilled on the Estate, mostly in the semiproved area: 44 by rotary, 13 by cable and 16 by star rigs, as compared with 34 by rotary, 11 by cable and 20 by star in 1938. The most important of the several semiexploratory wells sunk was No. 3075, which late in December was brought in at a depth of 4500 ft. with an initial production of 1500 bbl. per day, based on

Jan 1, 1940