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By J. S. Blakemore, E. O. Hall

SERRATED yielding, commonly called the Portevin-Le Chatelier effect, is known to occur in a wide range of alloys where the moving dislocations are considered to be locked by the diffusion of solute atoms to them. From the work of Cottrell,1 an approximate relationship between strain rate, E, dislocation density, p , and solute diffusion coefficient, D, giving rise to serrated yielding is: e =Dp

Jan 1, 1969

By L. J. West, R. M. Perrry

This chapter describes the rock mechanics studies performed for a high cut at a nuclear power station in Pennsylvania. Two units presently are being constructed on the Susquehanna River. When these units are completed, they will generate approximately 2100 MW of electricity. It was necessary to excavate about 1 million cu yd of rock to prepare the site. This excavation resulted in a high cut on the west and north sides of the station area with a maximum height of about 200 ft. The location of the high cut with respect to the plant facilities is shown on Fig. 1. The recommended slope angles ranged from 1 ½ (horizontal) to 1 (vertical) for the upper residual soil to ½ to 1 for the deeper competent rock. Because of the significant height of this cut and the fact that the slope is immediately adjacent to the proposed nuclear facilities, extensive stability analyses were performed prior to, during, and after excavation to evaluate the steepest angle at which the slopes could be safely cut. The studies consisted of evaluating both qualitatively and quantitatively all apparent factors which could affect the stability of the slopes. These factors include the strength of the material, the zones of weak material which are present along the planes of schistosity, the prominent joint systems, the ground water, and postulated seismic effects. FIELD AND LABORATORY STUDIES A comprehensive program of field explorations was performed to evaluate the geologic characteristics of this site. This program consisted

Jan 1, 1970

By David J. Reddish, Barry N. Whittaker

The characteristics of surface ground strains due to longwall mining are reviewed with special reference to U.K. coal mining observations. The current empirical method of estimating ground strain is discussed. A method of determining surface ground strain above a longwall extraction is described whereby strain can be accurately represented along a line in any direction. The discussion is supported with examples of its application to common subsidence engineering problems.

Jan 1, 1984

By L. C. Brown, E. B. Hawbolt

If a single-phase alloy is rapidly cooled such that insufficient time is available for an equilibrium transformation to occur, the high-temperature phase may be retained to room temperature or may undergo a massive or martensitic reaction. The massive or martensitic product develops without a composition change and usually has a crystal structure approximating an adjacent equilibrium phase. The characteristics of a massive transformation are intermediate between the equilibrium reaction in which long-

Jan 1, 1969

By M. Katzer, R. Klimpel, J. Sewell

The effect of using selective dispersants as wet grinding aids for ores is demonstrated on laboratory scale batch and continuous grinding equipment. A complete characterization of behavior is performed on a given ore to demonstrate correlations involving torque, % solids, net production rate, and slurry weight and volume loading. The relationship between such laboratory data and industrial scale testing results is very consistent.

Jan 1, 1982

By J. A. Rajala, R. W. Smith

The effect of increasing ionic strength, via monovalent and divalent ions, on alkyl sulfate flotation of hematite and quartz war investigated. The effects of collector chain length and pretreatment on this flotation were also studied. Sodium hexadecyl sulfate was shown to be a superior flotation collector to sodium dodecyl sulfate for recovery of hematite when there was no salt addition. Similar observation were made when sodium sulfate or sodium chloride was used to control ionic strength. Sodium dodecyl sulfate floated hematite better than its longer chutited counterpart under conditions of low pretreatment temperature and increasing calcium chloride concentration. The flotation recovery for all salt containing pulps was almost always improved after preboiling. Most of the results obtained when the pretreatment temperature was raised were attributed to increased solubility of the collector.

Jan 1, 1984

By J. H. Keeler

AN alloy of zirconium containing 18 atomic pct Cb was found to be body-centered-cubic and readily deformable at room temperature. The behavior of this alloy provided an opportunity to determine if

Jan 1, 1957

By S. Y. Ezz

The quality and extent of fluidization of fine iron ore beds with gases were investigated. Factors affecting the rate of reduction with H, and the sintering of the partially reduced material were studied. Trials to retard sintering by covering the particles' surface with nonsintering materials were successful. THE gaseous reduction of iron ores is a gas-solid reaction. Hence the fluidization technique seems ideally suited to it. However, a serious drawback

Jan 1, 1961

By W. N. Tanner

The wire-rope hoisting conditions at the mines of the Anaconda Coppcr Mining Co. in Butte, Mont, are very severe because of the conditions under which it is necessary to operate. A study was made, in the fall of 1919, for the purpose of changing these conditions in order to obtain longer rope and sheave life. There are at present in Butte hoisting engines equipped with wire rope as follows: 9 main hoists using flat ropes. 7 main hoists using 1 1/2-in. rope. 5 main hoists using 11/4-in. rope. 6 shafts using 11/8-in. rope. 2 chippy hoists using 11/4-in. rope. 9 chippy hoists using 11/8-in. rope. 15 shafts using 1-in. rope. 7 shafts using 7/8-in. rope. 1 shaft using 3/4-in. rope. In addition, there are a number of sinking engines wing 5/8-in, 3/4-in., 7/8-in., and 1-in. (15.9, 10, 22, and 25 mm) rope. THe flat ropes run from 1/2 by 71/2 in. (12.7 by 1905 mm.) to-3/8 by 4 1/2-in (9.5 by 114 mm.) and are used on the older hoisting engines, which arc set comparatively close to the shaft. Because of swelling and moving ground at some of the shafts, these ropes present certain difficulties ill operation that are more pronounced than with round ropes; they are, therefore, being superseded by round ropes as newer engines are being installed. They are, however, much more easily inspected and repaired than round ropes. In general, the practice in Butte is to use hoisting engines equipped with 12-ft. (3 7 m.) cast-iron drums, smooth faced, for 11/2-in. rope and 6-ft. cast-iron drums, smooth faced, lagged with 3/8-in. steel plate for 11/4 l1/8 and 1-in. (31.7, 28.6, 25 mm.) rope in main and chippy shafts. Cast-iron head sheaves, 12, 10, and 6 ft. in diameter, with grooves

Jan 1, 1923

By W. N. Tanner

The wire-rope hoisting conditions at the mines of the Anaconda Coppcr Mining Co. in Butte, Mont, are very severe because of the conditions under which it is necessary to operate. A study was made, in the fall of 1919, for the purpose of changing these conditions in order to obtain longer rope and sheave life. There are at present in Butte hoisting engines equipped with wire rope as follows: 9 main hoists using flat ropes. 7 main hoists using 1 1/2-in. rope. 5 main hoists using 11/4-in. rope. 6 shafts using 11/8-in. rope. 2 chippy hoists using 11/4-in. rope. 9 chippy hoists using 11/8-in. rope. 15 shafts using 1-in. rope. 7 shafts using 7/8-in. rope. 1 shaft using 3/4-in. rope. In addition, there are a number of sinking engines wing 5/8-in, 3/4-in., 7/8-in., and 1-in. (15.9, 10, 22, and 25 mm) rope. THe flat ropes run from 1/2 by 71/2 in. (12.7 by 1905 mm.) to-3/8 by 4 1/2-in (9.5 by 114 mm.) and are used on the older hoisting engines, which arc set comparatively close to the shaft. Because of swelling and moving ground at some of the shafts, these ropes present certain difficulties ill operation that are more pronounced than with round ropes; they are, therefore, being superseded by round ropes as newer engines are being installed. They are, however, much more easily inspected and repaired than round ropes. In general, the practice in Butte is to use hoisting engines equipped with 12-ft. (3 7 m.) cast-iron drums, smooth faced, for 11/2-in. rope and 6-ft. cast-iron drums, smooth faced, lagged with 3/8-in. steel plate for 11/4 l1/8 and 1-in. (31.7, 28.6, 25 mm.) rope in main and chippy shafts. Cast-iron head sheaves, 12, 10, and 6 ft. in diameter, with grooves

Jan 1, 1923

By S. Mukai, Y. Shah, T. Zshikawa, T. Wakamtsu

In order to recover coal concentrate of low ash and low iron content, the electrostatic separation of coal was studied. It is more successful in the corona discharge field to recover the coal concentrate of low ash and low iron content than in the field without corona discharge. The effect of humidity on the electrostatic separation of coal was then studied. From the experimental results, it was clear that the electrostatic separation was excellent in about 60% relative humidity of atmosphere. Thus, the separation of vitrite from coal is practicable by electrostatic separation. In recent years the demand for high quality coal containing low ash, low iron, and low sulfur has increased. To fulfill this requirement, a higher grade coal concentrate must be produced. Study on the electrostatic separation of coal has been performed for several years in the author's laboratory. From the results of this research, it was considered that the behavior of coal particles in the electrostatic field relates closely to the ash and iron content in coal. In the present paper, the electrostatic separation of coal in corona discharge field was studied in order to recover the high quality coal concentrate and then the effect of humidity on the electrostatic separation was investigated. PREPARATION OF COAL SAMPLES The coals from the Akabira mine, the Kushiro mine, the Miike mine, and the Oshima mine which are famous coal mines in Japan were used in this study. The ash contents of these coals are shown in Table I. From the results of the analysis of the coal samples by the Norelco X-ray diffractometer, it is recognized that the Miike coal includes mainly pyrite, quartz, kaoline, calcite, and epidote; the Kushiro coal: kaoline, quartz, and montmorillonite, and the Oshima coal: siderite, dolomite, and other substances. For the preparation of samples, the coarse pieces of coal were crushed to about 2 mm in diam and then ground in an agator mortar. The ground products were sieved and fractions of 10 — 14 mesh, 14 — 20 mesh, 20-28 mesh, and 28-35 mesh were prepared, respectively. APPARATUS OF ELECTROSTATIC SEPARATION The principal part of the apparatus of the electrostatic separation used in the experiments is shown in Fig. 1. In order to generate the corona discharge field, a needle-shaped electrode combined with a pole electrode is installed as the high tension electrode. In the case of investigating the effects of the humidity on the electrostatic separation of coal, the needle-shaped electrode was combined with a plate electrode instead of the pole electrode as shown in Fig. 2. The pole or the plate electrode was installed to promote the repelling of the charged particles by producing the electrostatic field between this electrode and the grounded roller. It seems to be very useful on the coal separation to install these combined high tension electrodes. SEPARATION OF COAL PARTICLES IN CORONA DISCHARGE FIELD The separation testings on the coal samples in the corona discharge field were performed by the apparatus as shown in Fig. 1. These experiments were carried out under the following conditions: feed size 20 — 28 mesh, room temperature, normal humidity and applied voltage 15-20 KV, and the combined electrodes including the needle-shaped electrode were negatively charged. The results of these testings are

Jan 1, 1968

By Bernard MacDonald

The writing of this paper was prompted by the discussion by H. M. Chance of the paper written by Thomas M. Chance,l and by the remarks of the editor in which he stated that while the matter contained in discussion did not refer to the original paper it " was presented as of interest to the operators of cyanide and other lixiviation processes dealing with fluid mixtures of varying specific gravity." For some years past the principle enunciated in the discussion referred to has been known to the writer and demonstrated by him to be an efficient and economical way of separating water or solution from solids in the cyanidation, lixiviation or acid leaching of ore pulps. In utilizing this principle in commercial practice he has invented a method whereby not only the separation of solution from solids may be effected in any given tank, but also the counter migration of the solids and solution may be effected continuously through a series of tanks in which the hydro-metallurgical treatment of ore pulps is being carried on. In effect this method is analogous to the counter-current system, but is different physically in that it is carried on throughout a series of tanks on practically the same level, continuously and automatically, by hydrostatic pressure and gravity-flow, without the aid of intervening pumps or elevators, at the same time that agitation is being carried on in the same tanks. In the Parral system, agitation is effected in tanks by a number of air lifts of comparatively small diameter through which the pulp is continuously transferred from the bottom of the tank and spouted horizontally on top of the charge. The spouting force of the several streams thus discharged maintains a rotary flow in the pulp charge which extends from top to bottom of the tank. This continuous transfer of pulp and the spiral flow from top to bottom of the tank maintains the pulp constituents in uniform proportions and meets the requirements of efficient treatment in a most economical manner. The quantity of compressed air required is very small, as the pulp is not lifted but simply transferred from the bottom to the top of the tank charge under hydrostatic balance. Fig. 1 gives a bird's-eye view of two adjoining tanks in any series equipped with the apparatus for producing the separation of

Jan 1, 1919

By G. R. Mansfield, W. B. Lang

THE third year of Government exploration for potash by the U. S. Geological Survey and the U. S. Bureau of Mines under the authorization of the act approved June 25, 1926 (Public 424-69th Cong.) is drawing to a close. The results thus far obtained are thought to be sufficiently interesting and satisfactory to justify the presentation of a brief preliminary account of the work. Review of Earlier Exploration The general geologic similarity of the Permian basin of Texas and New Mexico to the potash field of Germany had long ago suggested the possibility of the presence of potash salts somewhere in that basin, but petroleum exploration was then making little headway there and the necessary data could not be obtained. The discovery by Udden in 1912 of potash in brine from the Spur well in Dickens County, Texas, was the first direct evidence of its presence. In 1915-17 the U. S. Geological Survey drilled a test well with standard tools at Cliffside near Amarillo, but failed to find potash. Nevertheless, an observer has been kept in the field, at first in cooperation with the Texas Bureau of Economic Geology but since 1922 by the Survey alone, to secure data and samples from oil and gas tests. Since the discovery of oil in Reagan County in 1923 exploration by drilling has been rapidly extended to many parts of western Texas and southeastern New Mexico. The identification of the potash-bearing mineral polyhalite was first announced by the Geological Survey in June, 1921, the material having come from cuttings from the Bryant well in Midland County and the Burns well in Dawson County, Texas. Successive discoveries and announcements of similar purport aroused widespread interest in potash exploration, which culminated in the action by Congress already noted. Permian Salt Basin The Permian salt basin extends generally northeastward from western Texas and southeastern New Mexico through the Panhandle sections of

Jan 1, 1929

By J. Blodget Britton

IN the Journal of the Franklin Institute for May, 1870, there is published a description of a Colorimeter, together with a modification of the method proposed by Professor Eggertz, for determining combined carbon in iron and steel. An instrument of the kind there described, but of a little higher range, though in other respects not differing materially from the one originally made and used in the Iron-Masters7 Laboratory, I now submit to your inspection ; and I propose, also, to make some determinations minations with it for the purpose of showing how quickly they may be made, and enabling you to form some judgment of what reliance can be placed in the results. Professor Eggertz proposed only a single standard, and the solution to be tested should be diluted to exactly correspond in color with that of the standard, and the per cent. of carbon calculated after carefully noting and making allowance for the measures of water used in diluting. In practice, difficulty was found in bringing the color of the normal solution down to the exact shade of the standard; also other difficulties were met with in conducting the process, causing delay and interfering with the accuracy of the results. To materially overcome these, and after numerous attempts, an instrument such as is now before you suggested itself to me; and also I concluded to use a larger quantity of metal than directed by Eggertz, and, in addition, to filter the solution from its insoluble matter before making the comparison; and, more recently, to use an acid of just such strength as would completely dissolve the metal without the application of heat. Experimenting with these changes from the original method I obtained reasonably good results. The instrument, you will observe, consists of a series of tubes, sixteen in number, two and a half inches long, and about half an inch in diameter, standing upright, and securely fastened in a light, portable, walnut-wood frame, but separated one from the other so as to allow just sufficient space between to place for comparison the . tube containing the solution to be tested. The tubes are filled with

By Arthur C. Simmons

In common with all other producing areas of the United States, Pennsylvania enjoyed increased activity and prosperity during 1937 (Table I). Prices of crude oil were better than for any year since 1930, and the Bradford average was $2.599, compared with an average price of $2.60 in 1930. Production and drilling activities were increased over 1936, although drilling for oil represented almost entirely a program of secondary development in both the water-flood areas and the air-gas repressuring areas. Bradford Oil Field The Bradford oil field continued to produce the major portion of Pennsylvania oil; however, no changes occurred in oil-production methods during 1937. Practically all of the production in the Bradford field is by water-flooding and the total number of oil and water wells completed within the area increased from 3205 in 1936 to 4112 in 1937; an increase of approximately one-third over 1936 completions. The percentage of water wells is approximately one-half of the total completions, although any specific five-spot development will have a proportion of 55 to 60 per cent water wells and 40 to 45 per cent oil wells. Offsetti~ig and boundary oil wells probably will result in a division or percentage of 50 per cent oil and 50 per cent water wells. The quoted figures for well completions include the entire Bradford field, approximately 12 per cent of which is in Cattaraugus County, New York. It is possible to make a segregation of production, but it is not possible to segregate well completions. Production in the Pennsylvania end of the Bradford field in 1937 totaled 15,076,000 bbl., or a daily average of 41,300 bbl. compared with a daily average of 37,000 hbl. in 1936.

Jan 1, 1938

By H. M. Warrren

IN the past, steam engines were used in practically all cases for driving the machinery, in and about an anthracite breaker, and hence little or no accurate data were available as to the power requirements for starting and operating the individual machines, which make up the complete equipment. It was impossible to segregate the power necessary to drive each individual machine, first, because the equipment was driven in groups, and second, because it was impracticable to obtain graphic, integrated, or instantaneous records of the horsepower used. As a result of these conditions, it was found, when individual electric motors were applied to the various machines, that more accurate and complete data were needed in order to provide motors of the proper power and design for the particular services to be rendered. In order to obtain the desired information, the writers made and collected a number of tests, from time to time, on the individual motor drives in- electrically operated breakers, and as these tests have been of great value, it occurred to them that a paper giving the results might be of service to other engineers interested in similar installations. Table I shows the .results of these tests. All the motors tested were of the three-phase, 60-cycle, 440-volt, induction, squirrel-cage type, except a few, which, on account of size and starting conditions, were of the wound-rotor type. The instruments used in making these tests were: An integrating watt-hour meter, a graphic ammeter, and a graphic voltmeter. These instruments were connected in each motor circuit, and a record of a day's run of 9 hours was obtained from each machine. From these tests, the running light load, the average all-clay load, and the instantaneous peak readings in amperes, volts, and kilowatt input, were obtained. By means of the characteristic curves obtained from these motors at the factory, the power factor, the efficiency, and the horsepower output were calculated for each particular test. Starting tests were made by the brake-arm method, in which the torque in pounds was measured directly on a spring balance.

Jan 2, 1916

By Fred H. Poettmann

The vaporization characteristics of carbon dioxide in a League City natural gas - Billings crude oil system were studied at three temperatures, 38°. 120°, and 202°F and for pressures ranging from 600 to 8,500 psi. Variation of carbon dioxide concentration up to 12 mole per cent in the composite showed no effect on the equilibrium vaporization ratios (K values) of the hydrocarbon constituents or on the K value of carbon dioxide itself. It was shown that carbon dioxide is more soluble in crudes than in distillates which is contrary to the behavior of methane. A working chart of carbon dioxide K values is presented. INTRODUCTION The study of the equilibrium vaporization ratios of mixtures of paraffin hydrocarbons has been rather thorough.2,6,7,8,9 In the past few years considerable attention has been paid to the vaporization characteristics of the so-called noncondensable gases such as nitrogen, carbon dioxide, and hydrogen sulfide in mixtures of hydrocarbons. since they usually occur to some extent in most crude oils and natural gases.1,3,4,5 Knowledge of this behavior is useful to both the production and refining phases of the petroleum industry. This paper reports the equilibrium vaporization ratios (K's) of carbon dioxide in a mixture of League City natural gas and Billings crude oil, and compares them to those obtained in a natural gas-distillate system. The equilibrium vaporization ratios for the hydrocarbon components in this system had previously been studied by Roland.' In addition to the determination of the K values for carbon dioxide, the K values for methane and ethane were also determined in order to observe what effect, if any, the presence of carbon dioxide had on these K values. The concentration of carbon dioxide was also varied in order to observe the effect of this variable on the carbon dioxide K values. EXPERIMENTAL PROCEDURE The apparatus used in this study cotlsisted of a stainless steel equilibrium cell of about 2 liters capacity. The cell was mounted on trunions permitting rocking in a thermostatically controlled oil bath. Two high pressure valves fitted with steel tubing were mounted on the top of the cell. one was used for sampling the equilibrium gas phase and the other for sampling the equilibrium liquid phase by means of an induction tube within the cell. Stainless steel tubing from the bottom of the cell led to a mercury reservoir and manifold which was connected to a free-piston type pressure gauge manufac- lured by the American Instrunlent Ctr. and to a volumetric. putrip. The temperature of the oil bath was measured by means of a ralibrated mercury-in-glass thermometer. The recorded temperatures are believed to be accurate to ±0.5 °F. The pressures are correct to 22 psi. The crude oil used in this study was stock tank oil obtained from the Wilcox formation in the Billings Field, Noble County. Okla. The natural gas was obtained from the League City Field. Galveston County, Tex. The oil was treated with anhydrous calcium sulfate in order to remove the last traces of water. To insure a supply of constant composition gas at room temperature the cylinders of League City gas were cooled to about 30°F, inverted, and the condensed liquid was allowed to drain from the cylinders. The analysis of the gas and crude are tabulated in Table I. The carbon dioxide came from Pure Carbonic, Inc., and was .stated to have a purity of 99.5 per cent or better. The procedure used to obtain samples of the equilibrium liquid and vapor was similar to that employed by others making use of the rocking type equilibrium cell.6,7,8 The equilibrium cell was evacuated and calculated quantities of carbon dioxide, natural gas, and crude oil were charged to the cell to the desired pressure. In charging the equilibrium cell an attempt was made to maintain the ratio of the natural gas to crude oil as close as possible to that employed by Roland. After the cell was charged, samples of

Jan 1, 1951

By Fred H. Poettmann

The vaporization characteristics of carbon dioxide in a League City natural gas - Billings crude oil system were studied at three temperatures, 38°. 120°, and 202°F and for pressures ranging from 600 to 8,500 psi. Variation of carbon dioxide concentration up to 12 mole per cent in the composite showed no effect on the equilibrium vaporization ratios (K values) of the hydrocarbon constituents or on the K value of carbon dioxide itself. It was shown that carbon dioxide is more soluble in crudes than in distillates which is contrary to the behavior of methane. A working chart of carbon dioxide K values is presented. INTRODUCTION The study of the equilibrium vaporization ratios of mixtures of paraffin hydrocarbons has been rather thorough.2,6,7,8,9 In the past few years considerable attention has been paid to the vaporization characteristics of the so-called noncondensable gases such as nitrogen, carbon dioxide, and hydrogen sulfide in mixtures of hydrocarbons. since they usually occur to some extent in most crude oils and natural gases.1,3,4,5 Knowledge of this behavior is useful to both the production and refining phases of the petroleum industry. This paper reports the equilibrium vaporization ratios (K's) of carbon dioxide in a mixture of League City natural gas and Billings crude oil, and compares them to those obtained in a natural gas-distillate system. The equilibrium vaporization ratios for the hydrocarbon components in this system had previously been studied by Roland.' In addition to the determination of the K values for carbon dioxide, the K values for methane and ethane were also determined in order to observe what effect, if any, the presence of carbon dioxide had on these K values. The concentration of carbon dioxide was also varied in order to observe the effect of this variable on the carbon dioxide K values. EXPERIMENTAL PROCEDURE The apparatus used in this study cotlsisted of a stainless steel equilibrium cell of about 2 liters capacity. The cell was mounted on trunions permitting rocking in a thermostatically controlled oil bath. Two high pressure valves fitted with steel tubing were mounted on the top of the cell. one was used for sampling the equilibrium gas phase and the other for sampling the equilibrium liquid phase by means of an induction tube within the cell. Stainless steel tubing from the bottom of the cell led to a mercury reservoir and manifold which was connected to a free-piston type pressure gauge manufac- lured by the American Instrunlent Ctr. and to a volumetric. putrip. The temperature of the oil bath was measured by means of a ralibrated mercury-in-glass thermometer. The recorded temperatures are believed to be accurate to ±0.5 °F. The pressures are correct to 22 psi. The crude oil used in this study was stock tank oil obtained from the Wilcox formation in the Billings Field, Noble County. Okla. The natural gas was obtained from the League City Field. Galveston County, Tex. The oil was treated with anhydrous calcium sulfate in order to remove the last traces of water. To insure a supply of constant composition gas at room temperature the cylinders of League City gas were cooled to about 30°F, inverted, and the condensed liquid was allowed to drain from the cylinders. The analysis of the gas and crude are tabulated in Table I. The carbon dioxide came from Pure Carbonic, Inc., and was .stated to have a purity of 99.5 per cent or better. The procedure used to obtain samples of the equilibrium liquid and vapor was similar to that employed by others making use of the rocking type equilibrium cell.6,7,8 The equilibrium cell was evacuated and calculated quantities of carbon dioxide, natural gas, and crude oil were charged to the cell to the desired pressure. In charging the equilibrium cell an attempt was made to maintain the ratio of the natural gas to crude oil as close as possible to that employed by Roland. After the cell was charged, samples of

Jan 1, 1951

By Morgan Walker, C. D. Watson, Reid W. Bond, D. L. Trax

Common practice in the Mid-Continent until recently was to prolong the natural flow of oil wells as long as possible by agitation, and then swab for a short period until the well was put on the pump. Comparatively recently the gas-lift has superseded the swabbing and agitating period and in some cases encroached on the natural flowing life, particularly where it was evident that the potential oil capacity of the well was greater than the gas supply, or lifting medium. The majority of wells are finished with either 6¼, 65/8 or 8¼-in. casing and connected to a separator through a flow line which is usually 65/8 in. The flow line is generally designed to eliminate sharp turns and has reduced the gas-oil ratio and therefore increased the efficiency in a good many instances. Until recently all wells were allowed to flow without restriction against the possible trap pressure until it was deemed advisable to put them on gas-lift. This resulted in a fairly efficient flow during the early life of the well if the well was rather large but was usually inefficient in small wells and in the later flowing life of large wells, on account of the large area in the casing and therefore excessive slippage. Recently, considerable effort has been made to increase the efficiency of small flowing wells by running tubing to eliminate as much slippage as possible. With large wells there is a considerable trend toward back-pressuring, or beaning to find out whether it is possible to reduce the gas-oil ratios and increase the flowing life. The greater number of fields that have been back-pressured have been produced in that manner through necessity, either to restrict production for proration purposes or, in fields producing by hydraulic pressure, to reduce water encroaching. The recent Cromwell sand development in Little River is an example where both back-pressuring by means of high-pressure traps and beans and flowing through tubing were used to conserve gas, reduce the high gas-oil ratio and prolong the flowing life. It

Jan 1, 1930

By John J. Croston

IN the closing months of 1936 the copper industry gave every evidence that it was at last on the threshold of an improved era. At the beginning of the year prices stood at 9 ¼ ¢, which in itself was a great improvement over prices prevailing for the three previous years. Industry generally was showing signs of moving forward in this country, and business was definitely good in certain foreign quarters. The threat of war and preparations for rearmament in Europe and Asia acted as a further stimulus to purchasing. By midsummer the situation had so improved and stocks had been so reduced that the cartel of foreign producers (including American producers with foreign mines) decided to increase the production quota to 75 per cent on Aug. 1. Large-scale buying gave continued strength to the price and by Oct. 1 the quota was increased to 80 per cent, and again on Oct. 15, to 85 per cent. Notwithstanding this the price of copper continued its advance and on Nov. 1, with stocks declining continuously, the cartel increased operations to 95 per cent, then to 105 per cent on Nov. 5. In the meantime the domestic producers, because of the great increase in home consumption, had increased their production by nearly one-half. At the close of the year copper sold at 12¢ per pound, and since the turn of the present year has reached 17¢. This rapid increase has not been wholly justified. Much of the increase was due to the legitimate demands of recovering industry, but rearmament orders plus accumulation of reserve stocks in case of war, purchases in anticipation of labor strikes and purely speculative activities on the London Metal Exchange accounted for the balance. Certainly in view of the state of industry and the general world price level, it appears unnecessarily high. Talk of a copper shortage is sheer nonsense, the recent condition in the market being created by overbuying, leaving but a small volume for speculative supplies. It takes some months for an increase in mine output to reach the market, but production is again overtaking apparent consumption, stocks have begun to increase, and this, together with the reopening of many small

Jan 1, 1937