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By D. W. Carter, K. M. Fagin

Six new oil fields were discovered in the East and East Central Texas district during 1942. The Coke and Quitman fields, in Wood County, at this time appear to be the two most important oil discoveries for the year. The. four other oil fields discovered were Concord, in Anderson County; Kildare, in Cass County; Weiland (ClubLake), in Hunt County; and Larissa, in Cherokee County. The Rodessa lime in the Chapel Hill field, Smith County, provided the only new oil zone in older fields. The Hawkins field, Wood County, was the most active in drilling operations, 125 new wells being completed during the year. The Chapel Hill field tied the Coke field for second place with 30 completions each. The third most active field was Kildare, with 10 completions. Like the other oil-producing districts of the country, wartime restrictions reduced the number of oil and gas-well completions to 265 in 1942, compared with 964 completions in 1941. This represents a drop of 72 per cent and only a little more than one half enough to replace the 437 producing wells abandoned in the district during the year. Tn addition, the number of producing wells temporarily shut down nearly tripled, far two principal reasons: (I) the rule of the Petroleum Administration for War preventing operators from equipping more than, one well on each 10 surface acres with pumping or artificial-lift equipment, and (2) the Railroad Commission's issuance of various orders permitting the transfer of allowable for wells having high water-oil ratios and high gas-oil ratios to other wells capable of producing the same with less waste of reservoir energy. No changes were made in prices of crude oil in the district during 1942. Production and Probation The district produced 158,928,281 bbl. of oil and distillate during 1942, compared with 163,566,695 bbl. during 1941, which represents a decrease of 3 per cent. The East Texas field produced 120,680,595 bbl. of oil, compared with 130,377,793 during 1941; a reduction of 9,697,198 bbl., or 7.4 per cent. The production of this field represents 75.9 per cent of the district total, compared with the 79.7 per cent that it furnished in 1941. The district had an estimated basic daily oil allowable of 623,242 bbl. on Dec. 31, 1942. Approximately 31.8 per cent of the production in Texas during 1942 was supplied by this district, compared with 33 per cent during 1941- Changes in the annual production of newer and flush fields in this district are attributable either to a difference in the number of wells producing during the year or to changes in basic allowable and number of shutdown days due to shifting market dconditions brought on by the war. All regularly prorated fields in the district were shut down 123 days. Major exceptions were the East Texas field, closed128 days; Hawkiis, shut down 106 days; and Cayuga, Sulphur Bluff, Talco, and Rodessa, which

Jan 1, 1943

By Jr. D. C. Williams, D. V. Carter

The four new oil-field discoveries made in the East and East Central Texas districts during 1941 were the East Long Lake field, Anderson County; Pickering field, Shelby County; Pleasant Grove field, Rusk County, and Tri-Cities field, Henderson County. The discovery of oil production in the Pettit lime of the Lower Glen Rose was made in the Groesbeck (Barron) field in Limestone County and the Willow Springs field in Gregg County. Important extensions were made to the Pittsburg field, in Camp County, the Chapel Hill field, in Smith County, and the Hawkins field, in Wood County. The Hawkins field was extended sufficiently to more than double the number of proved surface acres. As usual the East Texas field led the district in the number of completions for the year. The second most active field during the year was the Hawkins field, with 250 new wells completed. The third most active was the Long Lake field, in which 50 wells were completed. Approximately 964 wells were completed in the district during 1941. Production and Probation The district is credited with having produced 163,566,695 bbl. of oil and distillate during the year. This represents a decrease of 4 per cent from the 170,424,685 bbl. of oil and distillate produced during the preceding year. The production of 130,378,620 bbl. of oil and distillate from the East Texas field represents 79.7 per cent of the total production of the district; that is, 6.3 per cent less than the production for the year 1940, The district had an estimated basic daily allowable of 614,982 bbl. of oil on Dec. 31. Approximately 33 per cent of the state's annual production was produced in the district, compared with 34.9 per cent for 1940. Since the majority of the fields in this district are subject to proration, any change in the annual production is attributable largely to changes in proration schedules and number of shutdown days. Fields subject to shutdown days were closed in for 113 days during the year, with the exception of the East Texas field, which was shut down 111 days. An order was promulgated by the Oil and Gas Division of the Texas Railroad Commission for encouraging the disposal of salt water and reservoir-pressure maintenance in the East Texas field. Discoveries Tex Harvey Oil Company'sNo. I S. E. J. Cartmel was completed as the discovery well for the East Long Lake field, Anderson County. Production was found in the Woodbine sand, the horizon from which the Long Lake field produces. The Pickering field, Shelby County, secures its production from the Nacatoch sand, found at an approximate depth of 1510 ft., in A. E. McKiernan's No. I, Pickering Lumbering Co. This field is in an area near the state line in which a number of relatively unimportant and

Jan 1, 1942

By Jr. D. C. Williams, D. V. Carter

The four new oil-field discoveries made in the East and East Central Texas districts during 1941 were the East Long Lake field, Anderson County; Pickering field, Shelby County; Pleasant Grove field, Rusk County, and Tri-Cities field, Henderson County. The discovery of oil production in the Pettit lime of the Lower Glen Rose was made in the Groesbeck (Barron) field in Limestone County and the Willow Springs field in Gregg County. Important extensions were made to the Pittsburg field, in Camp County, the Chapel Hill field, in Smith County, and the Hawkins field, in Wood County. The Hawkins field was extended sufficiently to more than double the number of proved surface acres. As usual the East Texas field led the district in the number of completions for the year. The second most active field during the year was the Hawkins field, with 250 new wells completed. The third most active was the Long Lake field, in which 50 wells were completed. Approximately 964 wells were completed in the district during 1941. Production and Probation The district is credited with having produced 163,566,695 bbl. of oil and distillate during the year. This represents a decrease of 4 per cent from the 170,424,685 bbl. of oil and distillate produced during the preceding year. The production of 130,378,620 bbl. of oil and distillate from the East Texas field represents 79.7 per cent of the total production of the district; that is, 6.3 per cent less than the production for the year 1940, The district had an estimated basic daily allowable of 614,982 bbl. of oil on Dec. 31. Approximately 33 per cent of the state's annual production was produced in the district, compared with 34.9 per cent for 1940. Since the majority of the fields in this district are subject to proration, any change in the annual production is attributable largely to changes in proration schedules and number of shutdown days. Fields subject to shutdown days were closed in for 113 days during the year, with the exception of the East Texas field, which was shut down 111 days. An order was promulgated by the Oil and Gas Division of the Texas Railroad Commission for encouraging the disposal of salt water and reservoir-pressure maintenance in the East Texas field. Discoveries Tex Harvey Oil Company'sNo. I S. E. J. Cartmel was completed as the discovery well for the East Long Lake field, Anderson County. Production was found in the Woodbine sand, the horizon from which the Long Lake field produces. The Pickering field, Shelby County, secures its production from the Nacatoch sand, found at an approximate depth of 1510 ft., in A. E. McKiernan's No. I, Pickering Lumbering Co. This field is in an area near the state line in which a number of relatively unimportant and

Jan 1, 1942

By D. W. Kestner

Recent developments and trends in the state of the art as being commercially applied to the pelletizing and sintering of metallic ores, concentrates and reverts will be reviewed. Both ferrous and non-ferrous materials will be covered. The influence of environmental considerations on the decision to build, the process selection, and design of the plants will be discussed. Use of coal in iron ore pellet induration will also be reviewed as the availability and price structure of oil and gas becomes a consideration to the plant operators.

Jan 1, 1980

By Brahm Prakash, R. Schuhmann

Chemical conditions for flotation and nonflotation of cassiterite and fluorite with oleic acid as collector and with alizarin dyes as modifying agents were studied by means of small-scale, vacuum-flotation tests. Artificial cassiterite was prepared for these tests by high-temperature methods, especially by crystallization from borax melts.

Jan 5, 1950

By I. Fatt

Study of a model which contains "dead-end" pore volume indicates that pressure transients are influenced by the amount of dead-end pore volume and by the resistance of the flow path between the dead-end pore volume and the main flow channels. A semi-empirical method is demonstrated that makes possible measurenment of the volume in the dead-end pores and the total pore volume. The difference between these two volumes is the volume of the flow channels. An indication of the flow resistance between the dead-end pore space and the lain flow channels is also obtained. INTRODUCTION In some engineering calculations the distribution of pore volume in a petroleum reservoir need not be known. For example, a material balance calculation treats a reservoir as an oil-filled tank. In other calculations the distribution of pore volume appears implicitly through use of the porosity and the relative permeability and capillary pressure characteristics. It is the purpose of this paper to point out that under certain conditions the exact distribution of pore volume must be known in order to interpret correctly transient flow behavior. Pressure transients during single-phase flow in porous media are usually said to obey differential equations of the form

By James R. Evans

Forecasting demand is an art as well as a science, and much personal judgment is required. National forecasts made for sand and gravel, crushed stone, and/or aggregate may be misleading or unhelpful locally. This is because of significant variation in demand within different geographic and/or political areas in the US, and/or the use of an inadequate data base and forecasting methodology. The best forecasts may be made for local or regional market areas, irrespective of geographic or political boundaries, provided a proper data base is available.1 The Bureau of Mines compiles detailed statistics on commodities sold or used in the construction industries and, therefore, is in an advantageous position to make national aggregate demand forecasts.

Jan 1, 1979

SINCE I have told you of the distillation of waters and the extraction of oils from things-all ingenious and useful processes-I wish to continue to speak of the arts. I am reminded that I first wish to write down for you the discourse that I made to you on another occasion a few days ago concerning the operation of a mint, so that if you have lost it from your memory (and this would not be surprising since you have had no practice in it) you may repossess it if you should need to practice it or even to talk about it, and if you find yourself in this activity it may not be new to you. I told you, as I believe you will remember and so again I repeat, that a very great and constant diligence is required by one who wishes to operate a mint well, or to have it operated, because it has many parts which it is necessary for anyone who enters this work to understand very well; indeed, if he wishes that all the work of his helpers be done well, he will have to do it himself. And if it were possible, he should have a hundred hands and a hundred eyes together, and at the same time should be in different places, because some loss often occurs in what is handled because of the carelessness of the workers or because of their little real trustworthiness. It is understood that such things require great hard labors and many kinds of knowledge. The material handled in this work is most often either gold or silver all ready to be spent, and these things are very attractive to those who handle them. In addition to being made into pieces of money likely to disappear, it is very easy to lose, and whatever part is lacking for any reason whatever [132v] brings detriment and loss to the patron since it is a thing of value. Therefore, in short, anyone who wishes to exercise this art well, without being fraudulent therein, must watch the weights with all care because the essence of this art is naught but the division of a quantity of weight into many exactly defined pieces and the alloying of gold by carats and of silver by leghe, exactly established in accordance with what the prince grants you as remedy.* If through negligence you exceed in perfection

Jan 1, 1942

By D. V. Carter, Dan C. Williams, Franklin M. Hackbusch

During 1939 little of consequence happened in East and East Central Texas in the way of oil discoveries. At the end of the year, there were 47 oil and gas fields in the district. Twelve other fields, 11 oil and one gas, have been abandoned. The ranking fields in order of the number of completions for the year were East Texas, Talco, and Rodessa (Texas portion). There were 511 oil wells (distillate wells included), 32 gas wells, and 257 dry holes completed in the district. Exploration, Discoveries and Extensions During the year, 113 exploratory wells were drilled, the same number as in 1938; four oil fields and one gas-distillate field were discovered. Perhaps the most important discovery, which has been named Barron field, was that of M. Samuel et al., No. 1 Barron in Limestone County. The wells in this field are of the gas-distillate type. Other than the Talco and Sulphur Bluff fields, which produce oil from the Paluxy sand (Upper Trinity), this is the first field on the Corsicana-Mexia fault zone to obtain commercial production from deeper Trinity strata. This "pay" is the Petit lime of the Lower Glen Rose of the Trinity group. The four oil discoveries were: Redland, Angelina County; Bazette, Henderson County; Rowe and Baker, Henderson County; and Marion County Shallow in Marion County. It is believed that the Bazette field, Navarro County, represents an extension of the Flag Lake field. For details concerning discoveries, extensions and important wildcat wells drilled during 1939 see Table 2. Production and Proration The district produced 175,053,729 bbl. of oil (distillate production included) which is a decrease of 4.0 per cent from the 182,369,484 bbl. (distillate production included) produced during 1938. The district's production for the year 1937 was 208,594,453 bbl. The East Texas

Jan 1, 1940

By D. V. Carter, Dan C. Williams, Franklin M. Hackbusch

During 1939 little of consequence happened in East and East Central Texas in the way of oil discoveries. At the end of the year, there were 47 oil and gas fields in the district. Twelve other fields, 11 oil and one gas, have been abandoned. The ranking fields in order of the number of completions for the year were East Texas, Talco, and Rodessa (Texas portion). There were 511 oil wells (distillate wells included), 32 gas wells, and 257 dry holes completed in the district. Exploration, Discoveries and Extensions During the year, 113 exploratory wells were drilled, the same number as in 1938; four oil fields and one gas-distillate field were discovered. Perhaps the most important discovery, which has been named Barron field, was that of M. Samuel et al., No. 1 Barron in Limestone County. The wells in this field are of the gas-distillate type. Other than the Talco and Sulphur Bluff fields, which produce oil from the Paluxy sand (Upper Trinity), this is the first field on the Corsicana-Mexia fault zone to obtain commercial production from deeper Trinity strata. This "pay" is the Petit lime of the Lower Glen Rose of the Trinity group. The four oil discoveries were: Redland, Angelina County; Bazette, Henderson County; Rowe and Baker, Henderson County; and Marion County Shallow in Marion County. It is believed that the Bazette field, Navarro County, represents an extension of the Flag Lake field. For details concerning discoveries, extensions and important wildcat wells drilled during 1939 see Table 2. Production and Proration The district produced 175,053,729 bbl. of oil (distillate production included) which is a decrease of 4.0 per cent from the 182,369,484 bbl. (distillate production included) produced during 1938. The district's production for the year 1937 was 208,594,453 bbl. The East Texas

Jan 1, 1940

By M. E. True, B. L. Stone

To cope with the problems encountered when drilling at greater depths and to reduce the amount of physical effort required on the part of drilling crews in making round trips, a new type of semiautomatic power-operated drilling machinery has been developed which permits round trips to be made without the drill pipe being touched by hand. This equipment consists of hy-draulically operated tongs which perform the stabbing, spinning, and tong-ing operations, and two power-operated racking units mounted in the derrick for carrying the pipe to and from the center of the hole and positioning it on the mat and in the rack. With this equipment all of the operations of the various units are controlled remotely by manipulation of hydraulic valve levers and electric switches. INTRODUCTION As horsepower rises to meet the demand for deeper drilling, it is necessary to increase the weight of surface drilling equipment. Also, the duration of repetitive operations in making round trips to change bits is greatly increased with depth. Harder formations encountered at greater depths reduce bit life rapidly, resulting in more frequent round trips and in some instances more time is consumed in changing bits than in drilling. Since the introduction of the first rotary employed to drill for oil in 18951, there has been relatively little change in the general procedure for making up, breaking out, stabbing, and racking drill pipe in making round trips to change bits. The conventional method of making round trips with the drill pipe requires that drilling crews lend strenuous physical assistance to manually operated tools. Although many new devices have been developed to improve efficiency, increase speed of making round trips, improve safety, and reduce the amount of physical effort required in handling drill pipe, it is considered a vital necessity to substitute automatic or semiautomatic power-operated machinery for many of our more or less manual operations if extremely deep drilling is to be carried out successfully on a production basis in the same manner as our shallower drilling of today. Field tests have been made of remotely controlled power-operated tongs, spinner, stabber, and racking equipment. The tongs, which include a built-in pipe spinner, are mounted on a column, are capable of gripping and supporting the weight of a 90-foot stand of drill pipe, and are provided with means for moving the pipe vertically as well as to and from the center of the hole. The racking equipment consists of two units, one at the level of the conventional monkey board and the other at the first girth on the ladder side of the derrick. Most of the physical effort of making round trips with drill pipe has been eliminated in that all of the operations of tonging, spinning, stabbing, and racking of pipe on the floor are controlled by an operator in a seated position by manipulation of hydraulic and electric valve levers and buttons. The driller is relieved of operating the cathead, leaving only the hoisting and slips to be controlled. Complete round trips are made without the drill pipe being touched by the drilling crews. Although the speed of pulling or running a single stand with the power-operated equipment is approximately the same as that with conventional equipment, it is possible to maintain this rate for long periods, whereas fatigue slows crews working conventionally during round trips, especially under adverse weather. After completing round trips with this equipment, drilling crews are not exhausted, consequently, are able to perform effectively their duties while drilling, which is essential for maximum over-all efficiency. Safety is substantially improved as the derrickman performs his duties from a platform enclosed by rails and the tong lines and spinning chain are eliminated from the derrick floor. The hazards encountered in racking drill pipe on the floor and in stabbing are also eliminated. Figure 1 shows a drawing of a derrick equipped with the power-operated drill'pipe handling equipment.

Jan 1, 1949

By M. E. True, B. L. Stone

To cope with the problems encountered when drilling at greater depths and to reduce the amount of physical effort required on the part of drilling crews in making round trips, a new type of semiautomatic power-operated drilling machinery has been developed which permits round trips to be made without the drill pipe being touched by hand. This equipment consists of hy-draulically operated tongs which perform the stabbing, spinning, and tong-ing operations, and two power-operated racking units mounted in the derrick for carrying the pipe to and from the center of the hole and positioning it on the mat and in the rack. With this equipment all of the operations of the various units are controlled remotely by manipulation of hydraulic valve levers and electric switches. INTRODUCTION As horsepower rises to meet the demand for deeper drilling, it is necessary to increase the weight of surface drilling equipment. Also, the duration of repetitive operations in making round trips to change bits is greatly increased with depth. Harder formations encountered at greater depths reduce bit life rapidly, resulting in more frequent round trips and in some instances more time is consumed in changing bits than in drilling. Since the introduction of the first rotary employed to drill for oil in 18951, there has been relatively little change in the general procedure for making up, breaking out, stabbing, and racking drill pipe in making round trips to change bits. The conventional method of making round trips with the drill pipe requires that drilling crews lend strenuous physical assistance to manually operated tools. Although many new devices have been developed to improve efficiency, increase speed of making round trips, improve safety, and reduce the amount of physical effort required in handling drill pipe, it is considered a vital necessity to substitute automatic or semiautomatic power-operated machinery for many of our more or less manual operations if extremely deep drilling is to be carried out successfully on a production basis in the same manner as our shallower drilling of today. Field tests have been made of remotely controlled power-operated tongs, spinner, stabber, and racking equipment. The tongs, which include a built-in pipe spinner, are mounted on a column, are capable of gripping and supporting the weight of a 90-foot stand of drill pipe, and are provided with means for moving the pipe vertically as well as to and from the center of the hole. The racking equipment consists of two units, one at the level of the conventional monkey board and the other at the first girth on the ladder side of the derrick. Most of the physical effort of making round trips with drill pipe has been eliminated in that all of the operations of tonging, spinning, stabbing, and racking of pipe on the floor are controlled by an operator in a seated position by manipulation of hydraulic and electric valve levers and buttons. The driller is relieved of operating the cathead, leaving only the hoisting and slips to be controlled. Complete round trips are made without the drill pipe being touched by the drilling crews. Although the speed of pulling or running a single stand with the power-operated equipment is approximately the same as that with conventional equipment, it is possible to maintain this rate for long periods, whereas fatigue slows crews working conventionally during round trips, especially under adverse weather. After completing round trips with this equipment, drilling crews are not exhausted, consequently, are able to perform effectively their duties while drilling, which is essential for maximum over-all efficiency. Safety is substantially improved as the derrickman performs his duties from a platform enclosed by rails and the tong lines and spinning chain are eliminated from the derrick floor. The hazards encountered in racking drill pipe on the floor and in stabbing are also eliminated. Figure 1 shows a drawing of a derrick equipped with the power-operated drill'pipe handling equipment.

Jan 1, 1949

By F. H. Labee

Questionnaires and special letters soliciting information were sent to a great many geologists, petroleum engineers, independent operators, and representatives of large companies in Arkansas, Louisiana, Texas and New Mexico. Replies to more than 50 per cent. of these letters were received. A survey of the facts and opinions presented in this correspondence will be made a little later, but first some of the general aspects of the problem will be reviewed. By "unit operation,"1 we mean the development and operation of a single entire pool, or reservoir, of petroleum by one management, on a systematic and scientific plan which is best calculated ultimately to extract from the pay sand and bring to the surface of the ground the largest possible amount of oil with the greatest possible total profit. No one, as far as the author has been able to ascertain, denies the advantages, both scientific and practical, of unit operation. All are agreed that it is sound in theory. It permits the proper distribution of wells, which should always be spaced on the ground according to a regular geometric plan with the intention of maintaining the same spacing all the way down and into the pay sand, or pay sands. This spacing will be different for different fields, depending on such variable factors as the lithologic character of the pay formation, the nature of the controlling structure, the depth of drilling, the viscosity of the oil, and so on. From the viewpoint of engineering practice, as applied to economical extraction of oil, there is no more important consideration than well spacing—well spacing in the pay formation, and not merely on the surface of the ground —for the method of well spacing has a direct bearing upon all such engineering practices as pressure control, repressuring by gas, the water drive, and SO on. H. C. Miller2 summarized the advantages of an ideal cooperative development plan as follows: "Among the more important advantages of

Jan 1, 1930

By M. G. Benz, J. F. Elliott

A. J. Goldak and J. Gordon Parr (U)iuersity of Alberta) —Margolin and Ence's paper reached us only a few days after we had submitted a paper on the structure of Ti2Cu to the AIME. Here, however, we only wish to point out an error in the paper (page 321): "Karlsson has reported the crystal structure of the first intermediate phase occurring in the Ti-rich portion of the Ti-Cu system to be face-centered tetragonal." Karlsson actually reported the structure of Ti3Cu (i.e., "the first intermediate phase") to be primitive tetragonal with four atoms per lattice point: Cu at 0, 0, 0; and Ti at 1/2, 1/2, 0; 0, 1/2, 1/2; and 1/2, 0, 1/2. Thus, Karlsson suggests a primitive lattice with an ordered arrangement of atoms located at corners and face-centers: Ence and Margolin suggest a random body-centered tetragonal structure—-with which our results agree. E. Ence and H. Margolin (authors' reply)— We do not agree that Karlsson has not reported the structure of Ti3Cu as face-centered tetragonal. The fact that Cu atoms are located at the corners and titanium at the face-centers does not indicate that the lattice is not face-centered. We are pleased that the discussers' results agree with our own.

Jan 1, 1962

By C. O. Bundranl, Peter Dehlinger, W. H. Browne

Brief laboratory investigations are described which attempt to determine optimum .sand concentrations in gel-sand and oil-sand1 well-treatments. The investigations apply to the case where sand acts as a propping agent in formation fractures. Both analytically and experimentally it is demonstrated that optimum sand concentrations can be defined. It is difficult to translate laboratory results to field treatments, however, since the relative distribution of sand and fluid in fractures may not be the same as injected. This is because fluid may penetrate the furtherest narrow portions of fractures, which would not pass sand. Optimum concentration of a monolayer of Ottawa sand in fractures of 0.025-in. width at the usual range of pressures encountered in treatments appears to be about 95 to 2 lb/gal. of gel. An investigation of abrasion of rock-walls by sand in treatments, described in the Appendix, shows that such abrasion is not probable in significant amounts. INTRODUCTION Experience in the Spraberry formation of West Texas, as well as in other formations, has shown that. sand is a necessary and vital part of gel-sand and oil-sand treatments. Many observers of treatments have also concluded that there seems to be an optimum range of sand concentration for these injections. Brief laboratory investigations were made at Battelle Memorial Institute to study flow in fractures with different sand concen- trations. To investigate the existence and range of optimum concentrations in the laboratory, however, necessitates knowledge of the mechanism by which the sand aids in increasing subsequent production. The action of sand in fractures is usually thought to be either that of a propping agent, thus providing a greater effective formation permeability; that of an abrasive in eroding fill material in fractures; or that of an abrasive eroding rock-wall irregularities along fracture surfaces. Investigations described in the Appendix show that sand does not appear to erode rock-wall materials appreciably. In a subsequent paper it is reasoned, at least for the Spraberry formation of West Texas, that the primary action of sand is not in removing fill materials in fractures. In this formation, and probably others, too, the main effect of sand appears to be that of a propping agent. Both analytical and experimental investigations were made for the case of a monolayer of sand acting as a propper, in which sand concentrations were determined that would, after treatment, permit flow of the maximum quantities of oil from the formation into a well. If too few sand grains are injected into fractures in which the bottom hole pressure has decreased appreciably below the original formation pressure, the confining pressure in the formation may become relatively large, thus compress the rock-walls around the sand grains, essentially close fractures, and so decrease the subsequent flow of oil. Similarly, if too much sand is used, the flow of oil will he impeded by the volume of sand present. THEORY Although an analytical approach to determining optimum sand concentrations involves gross assumptions.

Jan 1, 1955

By P. Somasundaran, R. D. Kulkarni

Reagentizing at elevated temperature, reported in the past as beneficial for the flotation of hematite using oleate, is studied here as a function of collector concentration, solution pH and ionic strength at various levels of conditioning temperature. The study revealed strong interactions between variables; particularly, the effect of conditioning temperature was found to strongly depend on the ionic strength of the solution. Thus, while an increase of conditioning temperature at lower ionic strengths or that of ionic strength at lower temperatures resulted in an increase of both flotation and grade, an increase of the former at higher ionic strength or that of the latter at higher temperatures caused a significant decrease in both responses. These observations have been explained in terms of the increased chemisorption of oleate at elevated temperatures and the temperature effect of ionic-strength on the salting out of the oleate from the bulk solution. The above effects which were first observed during Hallimond cell flotation tests were subsequently tested with Denver cell using low-grade iron ore. The results obtained using the two test procedures were in agreement with each other. The implications of these effects and interactions for process control of optimum flotation performance must be noted since variation in the levels of the above parameters are likely under plant conditions.

Jan 1, 1978

By M. L. Pearce

A comparison of the isotope-dilution, vacuum-fusion, and chemical methods of analysis for nitrogen in Si-Fe is made with particular emphasis on the effect of sample history. The superiority of the isotope-dilution method from the point of view of 1 HE analytical techniques used to determine nitrogen in Si-Fe have been subjected to close scrutiny in recent years primarily because of the marked influence of the element on the properties of the alloy. These investigations have led to a diversity of opin- both precision and accuracy is demonstrated. The solubility of nitrogen in 3.06 pct Si-Fe is investigated and the effect of silicon content on the activity coefficient of nitrogen is derived. ion regarding the reliability of the vacuum-fusion and chemical methods of nitrogen analysis when applied to si- Fe.'-' A majority of workers appear to favor the vacuum-fusion method over chemical methods particularly in those cases where part of the nitrogen may exist as silicon nitride or the total nitrogen content is very low. Contrary views have been expressed, however,' and it has been demonstrated that for some Si-Fe alloys both methods yield results which are significantly lower than those

Jan 1, 1963

By Allen Garrison

THE chemistry of clays and shales has been assuming increasing importance in the petroleum industry, and two factors have greatly influenced this trend. The first has been the growing evidence that the marine shales are source beds, and that the petroleum compounds have migrated to the sand reservoirs overlying or underlying these shales: the second has been the demand for drilling, fluids better adapted to penetrate these marine shales without difficulty and expense. ORIGIN AND GENERAL COMPOSITION OF CLAYS AND SHALES Clays, shales and surface soils are all closely related materials. They are mixtures of finely divided compounds formed during the weathering of the solid crust of the earth. Their nature is essentially colloidal; that is, their behavior is determined by the state of division of the materials and the surface reactions of the smallest grains. Many of their chemical changes affect only the exposed areas and do not involve the interior of the grains of matter. The extent of these reactions is more nearly proportional to the area of the substances than to their mass, therefore it is possible for a small. amount of a material in an extremely fine state of division to completely dominate the character of the mixture. More than 83 per cent of the crust of the earth is composed of three elements-oxygen, silicon and aluminum. Consequently, the corrosion products of the crust are predominantly aluminosilicates, or compounds of aluminum, silicon and oxygen. If we add the compounds of six elements-iron, calcium, sodium, potassium, magnesium and hydrogen-more than 98 per cent of the crust has been accounted for. These six elements, together with the first three, also appear in soils, clays and shales. But direct chemical analysis is of little value in describing the nature of such materials. Many chemical individuals may be present in variable amounts,. and the extreme subdivision of any one of the individuals may contribute qualities that dominate the mixture.

Jan 1, 1939

By H. F. Yancey, M. R. Geer

The importance of the size composition of coal is reflected in the difference in price of the various sizes of the same coal and in the large number of primary sizes and mixtures of sizes produced by the modern preparation plant to meet the demands of a market that in late years has grown increasingly conscious of coal size. The importance of size in the industrial and domestic uses of coal has its counterpart in the role played by size composition in the laboratory examination of coal. Investigation of many of the physical properties of coal in their relation to its uses requires an evaluation of size composition. In fact, the Standards on Coal and Coke issued by the American Socaiety for Testing Materials in 1936 contains 12 standard methods of testing that involve some use of size composition. The screen analysis is, of course, the standard method of determining size composition, whether the material is coarse run-of-mine coal or fine pulverized fuel. Custorriarily, the analysis is reported as the weight percentages retained on or passing each of a series of testing screens, the number of which may range from only two or three to as many as 20. When more than two or three sieves are used, which is usual, the number of weight percentages obtained is so great as to make the analysis difficult to comprehend. Direct comparison of analyses made 011 the same sieves is hard, and comparison of analyses covering the same range of sizes but made on different sieves is next to impossible. Consequently, a frequent purpose of sizing tests-—-correlation of size with properties and charactcristics related to size-—is rendered difficult. Less cumbersome means of expressing size composition have been attempted with various degrees of success. An average particle size, calculated by any of several formulas, is useful for some purposes, also the weight percentage retained on a single sieve finds some application as a

Jan 1, 1938

By M. R. Geer, H. F. Yancey

The importance of the size composition of coal is reflected in the difference in price of the various sizes of the same coal and in the large number of primary sizes and mixtures of sizes produced by the modern preparation plant to meet the demands of a market that in late years has grown increasingly conscious of coal size. The importance of size in the industrial and domestic uses of coal has its counterpart in the role played by size composition in the laboratory examination of coal. Investigation of many of the physical properties of coal in their relation to its uses requires an evaluation of size composition. In fact, the Standards on Coal and Coke issued by the American Socaiety for Testing Materials in 1936 contains 12 standard methods of testing that involve some use of size composition. The screen analysis is, of course, the standard method of determining size composition, whether the material is coarse run-of-mine coal or fine pulverized fuel. Custorriarily, the analysis is reported as the weight percentages retained on or passing each of a series of testing screens, the number of which may range from only two or three to as many as 20. When more than two or three sieves are used, which is usual, the number of weight percentages obtained is so great as to make the analysis difficult to comprehend. Direct comparison of analyses made 011 the same sieves is hard, and comparison of analyses covering the same range of sizes but made on different sieves is next to impossible. Consequently, a frequent purpose of sizing tests-—-correlation of size with properties and charactcristics related to size-—is rendered difficult. Less cumbersome means of expressing size composition have been attempted with various degrees of success. An average particle size, calculated by any of several formulas, is useful for some purposes, also the weight percentage retained on a single sieve finds some application as a

Jan 1, 1938