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By J. A. Knox, R. M. Lasater, J. M. Tinsley

Chemical squeeze treatments have been used to provide temporary relief from certain production problems. The chemical fracture-squeeze technique, combining the effects of a fracturing treatment and a squeeze operation, has been more successful than conventional squeeze operations. Knowledge derived from well stimulation and reservoir engineering research provides a means for predicting the theoretical effective life of such a treatment. Analysis of theoretical equations and concepts developed allows selection of improved treatment techniques based on specific formation conditioins. Theory used in this analysis was developed as an extension of previous electrical model studies made to establish the expected flow and pressure profiles adjacent to a fracture system. The chemical fracture squeeze technique can be utilized in the economic application of corrosion inhibitors, emulsion breakers and paraffin and scale inhibitors. Application of this technique is shown to be effective. The slow return rate of injected chemicals, controlled by the resultant flow profiles and treatment variables, permits extended periods of chemical effectiveness. Results of field treatments are given, showing that the concepts outlined above for chemical fracture-squeeze treatments are valid and that applying this technique can help alleviate many current production problems. INTRODUCTION Much progress has been made in the last 10 to 15 years in developing chemicals for use in stimulating wells, maintaining production and protecting well equipment from damage due to corrosion. Not too many years ago, some wells seemed to dry up or wear out. In many cases the wells were produced as long as possible without any attempt at maintaining productivity. Even with the advent of new and better stimulation techniques, a rapid decline in production was observed. Methods of removing and, in some instances, preventing damage have been developed. Among thosc factors responsible for uneconomical production are scale, paraffin, corrosion, bacteria, water blocks and emulsions. Soluble scale-prevention chemicals have been developed1,2 that can be placed in a formation along with frac- turing sand. As the water produces back across this bed, the solid material dissolves slowly and can provide long-term protection from scale. However, bottom-hole temperature and salinity of produced water vary widely and both these factors influence the rate of solubility. Scale inhibitor composition is also a controlling factor. Some of the solid material may be crushed, increasing the surface area exposed to water and increasing the rate at which it dissolves. Some of the material may never be contacted by water and can be lost. However, this type of treatment has been very successful in many instances and has helped maintain economical production for extended periods of time. Liquid scale inhibitors, which are more widely applicable and more stable, have been developed in recent years; however, because they are liquids, their use has been restricted to treatment down the annulus, using metering pumps to provide proper concentrations in the produced fluid. This has prevented use in wells containing packers, in dually completed wells and in gas-lift and flowing wells. Wells that operate with an open annulus may also experience severe corrosion problems due to introduction of oxygen. Paraffin inhibitors3 have been developed that can be fractured into a well as particulate solids to be slowly dissolved in the produced fluid. These materials are not usually effective in wells with a bottom-hole temperature in excess of 120F since solubility rate may be too fast if that temperature is exceeded or if aromatic content of the oils is unusually high. Corrosion inhibitors have been developed that can be fractured' into a well for long-term feedback, but development of a material with proper solubility or feed rate has been difficult. Corrosion inhibitors are available in many different forms. Liquids have been lubricated down the annulus or sticks or pellets dropped down tubing. Inhibitor squeeze treatments5 devcloped a few years ago led to development of inhibitors with particularly strong film-forming properties.6,7 This technique basically involves displacing a highly concentrated solution of the inhibitor into the formation through the tubing. Kerver and Hanson8 studied the adsorption properties of inhibitors on various types of formations. They showed that, even though the inhibitor was displaced radially into the true permeability, it could be produced back for a long period of time because of slow desorption from the rock. Methods developed for monitoring the return of these inhibitors generally have established 1 to 6 months as the effective limit before retreatment is necessary.9 Inhibitors displaced into the interstices of the formation sometimes cause emulsions that either hamper production or cause treating problems on the surface.

By C. E. Kemp, A. B. Dyes

Results of a field research project on the thermal recovery of oil by movement of a combustion front are presented. This field test was conducted in the South Belridge field, This The war paitern was a Southsing1e 2.5-acre five-spot pattern in the 700-ft deep Tulare sand. Results of this project indicate the technical feasibility of producing high viscosity, low-grallity crude oils by thermal means. It was demonstrated that heavy oils could be moved rapidly over considerable distances by thermal drive, and that high percentage recoveries of oil could be effected. The bulk of the oil recovery came after arrival of the burning front at a production well. However, rapid corrosion and high-temperature failure of conventional pipe and equipment both below and above surface occurred. Stainless steels gave more satisfectory performance under these conditions than did conventional steels. Oxygen was seldom observed in gas from wells ahead of the burning front, and it appears that the front was continuous throughout the life of the experiment. INTRODUCTION During late 1953 and early 1954, industry-wide attention was focused on the thermal recovery of oil by movement of a combustion front through an oil zone. Two separate Oklahoma field tests were described in publications by Kuhn and Koch, and Grant and Szasz. To obtain basic information needed for making engineering and economic appraisals of commercial recovery of heavy oil by this thermal recovery method, a new field research projecta3,4 was started May 31, 1955. Twelve oil companies contributed to this project with General Petroleum Corp. as operator. Since combustion recovery experiments* with heavy oils in other areas had been conducted in small patterns,"' an important purpose of this test was to determine whether the process could be operated in a pattern of near-commercial well spacing. The south Belridge field, located 30 miles north of Taft, Calif., was chosen because its oil sands are similar to many heavy oil sands which typically have low primary recovery and leave a large amount of oil in place. such fields are not particularly suited for common secondary recovery methods. DESCRIPTION OF TEST SITE The test interval was a Tulare sand at a depth of about 700 ft. Nine test wells were drilled, cored and completed from Oct., 1955, through Jan., 1956. The initial pattern shown on the map, Fig. 1, consisted of an injection well (II)', four producing wells (1P-4P), and four observation wells (IT-4T). An old well (81) was also recompleted for use as an observation well. The area enclosed by the original four production wells was 2.5 acres; the distance from the injection well to each production well was 233 ft. During the combustion period, Well 5P was drilled to replace Well 2P, and Well 6P was drilled to replace Well 3P. The new wells were 25 ft beyond the old production wells along a diagonal from the injection well, and resulted in an increase in pattern area to 2.75 acres. Isopachs are shown in Fig. 1. The average thickness of the oil sand in the test pattern was 30 ft. Fig. 2 presents two cross sections through the test pattern. Oil sand is represented by white and claystone by gray. The dashed lines indicate layers of conglomerate grading to claystone. The sand thickness was fairly uniform throughout the test pattern except in the 1P area. The sand body dips gently from the northwest to southeast, about 3 degrees from horizontal. The sand is unconsoli-dated, and grades from very fine material to pebbles as large as 2 in. in diameter. Table 1 presents the average initial properties of the formation. The in-place porosity of 37 per cent was estimated from the porosity of coke-consolidated cores taken after combustion. Original core analyses data were adjusted to 37 per cent, giving pore volume saturations of 60 per cent oil, 37 per cent water, and 3 per

Jan 1, 1887

By R. F. Ashton, D. S. Thompson

In reporting results of precipitation hardening experiments, it is customary to include such conditions as solution heat-treatment temperature, specimen size, and quench medium as well as the aging time and temperature. One portion of thermal history that is often overlooked is the effect of the heating rate employed to achieve the aging temperature. It is the intent of this note to demonstrate the importance of the rate of heating to aging temperatures. This work was carried out on the aluminum alloy 7075 aged at 162oC, a temperature commonly used to obtain stress corrosion resistant tempers. A 2 in. thick plate of 7075 was quenched into 24°C water after solution heat-treatment for 2 hr at 470°C. Approximately 13 in. around the periphery of the plate was discarded to minimize quench rate variations, and the remainder was divided into 0.5 by 1.8 by 2.0 in. blocks which were held at room temperature, 24oC, for 4 days. This aging, or incubation period, at room temperature allowed a copious supply of GP-zones to form. Blocks were then heated at various rates to 162oC using the practices shown in Table I. Both single- and two-step aging practices were employed for each heating rate. The single step consisted of heating directly to temperature at the indicated rate while the two-stage practice included an interruption of heating for 7 hr at 107°C. In the case of the two-stage 100°C per min heating rate experiment, the specimens were returned to room temperature after 7 hr at 107°C where they were held for 16 hr be-fore finally heating at this rate to 162°C. This devia-tion in practice is not considered to be significant. Blocks were removed after various times at 162oC, and aging curves were determined from duplicate R. F. ASHTON and D. S. THOMPSON,Member AIME, are Senior Scientists, Metallurgical Research Division, Reynolds Metals Company, Richmond. Va. Manuscript submitted December 2. 1968. IMD Table I. Aging Practices Two-step Single-Step Heating Rate* Aging Aging Heating Method oC per Min A B Programmed Air Oven 0.23 * 0.01 C D Programmed Air Oven 0.93 ? 0.03 E F Air Oven at Temp -10 G H Oil Bath at Temp ˜100 *Heating rate was measured with a thermocouple at the center of a specimen. An average value between the starting temperature and 3°C below the aging temperature is reported for practices E-H. PRACTICES 70 — A B C E and G 50 - 2 4 6 810 20 40 60 HRS.AT 162°C Fig. 1—The influence of processing variables on 7075 aging curves. Fig. 2—7075 aged according to practice H (single-step aged, fast heating rate) for 3 hr. Magnification 100,000 times.

Jan 1, 1970

By V. N. Mackiw

IN the process employed by Sherritt Gordon Mines Ltd. for the production of metallic nickel, a sul-fide concentrate is leached with ammonia and air under pressure. Following the removal of iron, copper, and other impurities, there remains a purified solution having the following analysis: 40 to 50 g per liter Ni, 200 to 400 g per liter (NH4)2 SO 4, and 20 to 30 g per liter NH3. Metallic nickel is reduced from this solution by hydrogen under pressure at 300' to 350°F in mechanically agitated autoclaves. A catalyst, ferrous sulfate, is required to initiate the first reduction. After the reduction, the depleted solution is discharged, leaving the metallic nickel in the autoclave. The nickel produced, being in a finely divided form, is used as a catalyst for the reduction of the next batch of solution. Upon repeated use the metallic nickel particles increase in size and become more compact, resulting in the production of a powder with higher apparent density. For this reason, each reduction is termed densification. Finally, when the burden of metal powder in the autoclave becomes too great to obtain effective agitation, both powder and depleted solution are discharged. The autoclave is then filled with fresh solution, ferrous sulfate catalyst added as before, and a new cycle started. The operation is described in earlier publications.1-6 A comprehensive historical review of the reduction of metals from solutions in general was given in a paper by Schaufelberger.7 The experimental data presented in this paper were taken from the work done in the Research Laboratory of Sherritt Gordon Mines Ltd. in Ottawa during the development of the process in 1951 and 1952. The results of the work were tested on a pilot plant scale in Ottawa in the period 1952 to 1953. Following laboratory and the pilot plant studies a commercial process has operated successfully since 1954 in the Nickel Refinery of Sherritt Gordon Mines Ltd. in Fort Saskatchewan, Alberta. General Experimental Technique The experiments were carried out in a stainless steel, 1-gallon, agitated autoclave designed and manufactured by Autoclave Engineers Inc. The inside dimensions of the vessel were 5 in. diam and 12 in. depth. The stirrer consisted of a 1/2 in. diam shaft 11 in. long fitted, with an axial flow type impeller (three blades bent to throw downwards) and a radial flow

Jan 1, 1958

United Engineering Trustees, Inc. GEORGE A. EASLEY H. G. MOULTON A. L. QUENEAU The Engineering Foundation GEORGE D. BARRON E. DEGOLYER A. L. QUENEAU Engineering Societies Library Board H. K. MASTERS A. B. PARSONS, Ex-officio F. F. SHARPLESS H. H. SWEETSER ARTHUR L. WALKER

Jan 1, 1934

"Only the coal of the Sunnyside district in Carbon County is coked. Two companies, the Utah Fuel Company and the Columbia Steel Corporation, operating adjoining mines at Sunnyside and Columbia, produce coke.The Utah Fuel Company has 819 beehive coke ovens at Sunnyside. Only 350 ovens are being operated at the present time, largely because the smelters which had been using Sunnyside coke changed their equipment from blast furnaces to reverberatory furnaces.The Columbia Steel Corporation operates a plant of 33 Koppers type by-product coke ovens at Ironton, near Provo. About 800 tons of coal are used per day to produce coke for the company's iron blast furnace plant pie ovens produce about 400 tons of coke, 12,000,000 cubic feet of gas, 9,000 gallons of coal tar, 3,000 gallons of benzol and several tons of ammonia sulphate per day.The total coke production for the State from the earliest output of record in 1880 until June 30, 1924, is 5,947,714 tons."

Jan 1, 1925

By Carl Floe

THE possibility of separating the various constituents of mixed ores or metalliferous products by differentially producing their soluble sulfates has not received the consideration that it deserves. The production of the soluble sulfate may be accomplished by baking the ore with sulfuric acid or by treating it with gases containing oxides of sulfur. This paper is primarily concerned with the first method. The procedure used was to mix the material with a solution containing a definite weight of sulfuric acid, baking the mixture at various tempera-tures and then leaching out the soluble sulfate with water. The amount of acid used was calculated to produce certain desired soluble sulfates. The temperature of baking depended on the decomposition points of the sulfates involved. The object was to prevent the formation of or to decompose certain sulfates while leaving a maximum quantity of another sulfate in a water-soluble form. This procedure has two possible advantages over the ordinary method of leaching with an aqueous solution of sulfuric acid. First, a more selective leach may be obtained, and second, the higher temperatures and stronger acid concentrations involved will permit a better recovery of materials that are difficultly soluble in relatively dilute aqueous sulfuric acid solutions. The method of sulfuric acid baking followed by water leaching is not new, as it has been applied in the treatment of various metalliferous materials such as the recovery of cadmium from flue dust1, the re-treat-ment of zinc leach residues2 and the working up of electrolytic slimes3.

Jan 1, 1936

By J. S. Levine

A series of four displacement experiments has been run in a large alundum core. Flow potential distribution in each liquid phase was measured continuously through oil-wet and water-wet capillary barriers, using a null-point pressure balance, and saturated distribution was determined from electrical resistivity measurements. A method has been devised for calculating the effective (and relative) permeability to each phase at any time and at any point in the flow system for the transient displacement process. Relative permeability points have been calculated and average curves drawn for oil displacing water and water displacing oil. The values of dynamic capillary pressure have also been determined. Data have been substituted into the generalized Buckley-Leverett fractional flow equation and a comparison between actual and theoretical breakthrough recoveries is shown. Displacement experiments have been performed in the laboratory for many years in an effort to determine the effect of a number of parameters on multiphase flow in porous materials. In the literature of petroleum technology, Wyckoff and Botset' were among the first to develop the relative permeability concept and to show experimentally that oil, gas, and water can flow simultaneously through a porous medium in a precise way governed by certain fluid properties, by the relative saturation of each fluid, and by characteristics of the medium itself. Somewhat later, Leverett2 and Hassler, Brunner, and Deahl11 developed some theoretical concepts of capillary behavior in porous materials. The work of Buckley and Leverett3 presented a theoretical analysis of immiscible liquid displacement based on the equation of continuity and the Darcy equation for viscous flow of each fluid. Subsequent investigators attempting to verify the Buckley-Leverett equation have, in general, deliberately neglected the capillary pressure term or have performed experiments in such a manner that it could be neglected. Terwilliger, et al4 in 1951, obtained agreement between theory and experiment for the constant rate displacement of water by gas in a long vertical sand column. Rapoport and Leas5 have investigated the

Jan 1, 1955

By Spencer S. Shannon

This chapter is concerned with the uses, geology, exploration, evaluation, preparation for markets, and future of 90thorium and 39yttrium, along with 14 rare-earth elements. The rare-earth metals or lanthanides were divided into three categories by Berzelius. The cerium subgroup is comprised of 57lanthanum, 58cerium, 59praseodymium, 60neodymium, and 62samarium. 61Promethium does not occur naturally. The terbium subgroup includes 63europium, 64gadolinium, and 65terbium. The remaining lanthanides are placed in the yttrium subgroup. Strictly speaking, yttrium is not a rare earth. Because the properties of yttrium resemble those of heavy rare earths, its name has been used as a designating adjective. The yttrium subgroup includes 66dysprosium, 67holmium, 68erbium, 69thulium, 70ytterbium, and 67lutetium. Rare-earth elements, especially those of the same subgroup, tend to occur together rather than in discrete minerals.

Jan 1, 1975

Not many accounts of mining methods or labor conditions in the mines in early days can be found; all that have seemed to be authentic have been included in the preceding chapters. In practically every field opened before 18.10 the first coal was recovered by quarrying, or strip mining, the operations, of course, being by hand and on a very small scale; new places were opened as soon as mining became difficult or expensive. Where it became necessary to drift into the hillsides, the first coal was taken out by sleds, and later by small wagons, the power being supplied by the miner, often assisted by dogs. Wooden rails then came into use with small cars running on them. These cars were very small, usually holding only a few bushels; in the Belleville, Illinois field as late as 1863 cars having capacities of 10, 12, 14 and some as large as 30 bushels were in use. It was not until late in the 1830's that horses or mules came into use for haulage purposes in the Pittsburgh region, although some had been used in the Richmond, Virginia field at an earlier date. Coal was usually undercut by hand and wedged down, until explosives came into general use, and in nearly every field the coal was forked into the cars, the fine coal, or slack, being left in the mine. Hours worked were very long, but few records remain to show what they were at different places and times; there was undoubtedly a great variation between districts and mines. Roy stated a miner could often produce 5 or 6 tons in a day of 8 or 9 hours in a 5 or 6 foot seam, but in another seam possibly could mine only 3 1/2 to 4 tons. He estimated an average day's work in a four foot seam at about 3 1/2 tons.1 In a strike in the Belleville field in 1863 it was found that an average skilled miner in the field could probably produce 4 to 5 tons a day.2 This was only the coarse coal loaded and did not include slack. In 1873, a coal undercutting machine was tried at a mine about two miles from Brazil, Indiana, said to be the first coal machine ever invented in the United States. It was run by a 5 H.P. steam engine (later to be changed to compressed air), and consisted of an iron rim, four feet in diameter with movable steel teeth placed about one foot apart. The rim

Jan 1, 1942

By P. H. G., Durville

ANY metal which contains even a small percentage of aluminum possesses certain peculiarities of appearance and properties which are exhibited both when the metal is melted and after it solidifies. Pure aluminum, or an alloy containing a small proportion of aluminum, can be melted without flux-except for a layer of charcoal-because a film of aluminum oxide and metal forms at the surface of melted aluminum. Although very thin, this film is air-proof, and it prevents the metal underneath from oxidizing. This oxidized film does not move easily on account of its toughness and high surface tension. One very important point in connection with this process of still casting has not been strongly enough stressed, namely, that the same kind of surface film with the same peculiarities forms over the surface of all melted alloys that contain even a small proportion of aluminum. Experienced foundrymen know how desirable it is to cast aluminum under its "skin" or under the surface of the film which tends to remain still. In the case of red copper, when in fusion, the surface shows pure copper only. This' is due to the fact that liquid copper constantly absorbs the copper oxide which forms on the surface. By closely examining melting copper the oxide can be seen dissolving in the bath, and going into solution just as pulverized sugar dissolves in water. When copper is cast in the open, either in wire bars or cakes, the surface of metal exposed to the air is covered by a film of black oxide that cannot be absorbed by the metal.

Jan 1, 1927

By Mark E. Emerson

INTRODUCTION A long time has passed since geologists encountered encouraging mineralization in their regional exploration program for base metals deposits. Detailed drilling during the following two field seasons served to delineate the configuration of the deposit. Various statistical techniques were employed to provide confidence levels regarding the extent of the reserves and to categorize them according to whether proved, indicated or inferred. At this juncture, it appears that the company has an orebody. Time elapsed? - three years; money spent? - $2.5 million. Much remains to be done before the orebody becomes a mine. The company urgently needs to develop new orebodies to replace its existing mines which are being depleted. It therefore has expended sizable amounts in exploration, the life blood of the company. A staff of specialists is maintained to evaluate new projects and to conduct feasibility studies. The scale of new mining projects today is beyond the resources of most mining companies. Bank financing, therefore, is often vital if the company is to survive. The following scenario describes how a company goes about evaluating mine projects and what is needed to meet lender's criteria in securing the needed financing. MINE PLANNING Now that the company engineers have taken over the project, their concern is no longer with finding ore but in developing it. An exploration shaft has been put down and a tunnel driven into the orebody to verify, on a large scale, what has been seen so far only in pencil- like drill cores. A large tonnage bulk sample is mined and shipped off to an independent metallurgical process laboratory for beneficiation testing. The budget is expended to cover engineering studies. Preliminary capical and operating costs are developed in- house and profitability studies are made based or1 assumptions concerning the markets for the main product and the indicated gold, silver, and other by-products. Time elapsed? - four years; cost to date? - $3.5-$4.5 million. The staff prepares its own pre-feasibility study. After review, the Executive Committee authorizes management to proceed with full-scale studies. The task is to make preliminary designs and to develop definitive capital and operating cost estimates. Specialized consultants will be engaged to study slope stability for the open pit and rock strength if underground recovery proves more feasible. If it is near the sea, an oceanographic report might be commissioned to see if the tailings can be disposed of off shore. Environmental impact studies are commissioned from a firm familiar with government requirements and regulations in this important area. The company subscribes for an expensive multi-client study of the supply- demand-price outlook for the product to support its own long-range price forecast. Now all the numbers are available to make a definitive appraisal of the value of the project. Cash flow analyses and sensitivity studies follow. Reams of computer printouts are generated. Time elapsed: five years. Amount spent? - up to $9 million, depending on the size, complexity and attractiveness of the project. Marginal projects always take longer. Finally, an engineering and construction (E&C) company is given the task of integrating and compiling all the data into a feasibility study. The results of dozens of reports, memoranda, computer printouts, and charts are boiled down to one final summary report of a few hundred pages together with conclusions and recommendations. After thoughtful review at a board meeting, the directors authorize management to proceed with detailed engineering work - provided that

Jan 1, 1985

By Frank C. Greene

The principal event in the development of oil and gas in Missouri in 1942 was the drilling of the Cities Service Oil Company's No. I Jim Cook, in the northwest corner, NW. 1/4 sec. 32, T. 65 N., R. 39 W., Atchison County, in the northwest corner of Missouri. This well, not yet completed, bailed several barrels of free oil in about 27° Baume from a sand called the Bartlesville by those in charge, at a depth of 1450 ft. The well is on a block of leases obtained after the area, which is covered by several hundred feet of glacial drift, had been prospected by core drilling. Earlier in the year the same company drilled a well on the Glen Gray farm in the southwest corner, SW. 1/4 sec. 29, T. 65 N., R. 39 w., to a depth of 2427 ft. in the Hunton lime with a rotary drill. Oil stains in this hole led to the drilling of the second well. Table i .—-Wells Drilled for Oil and Gas in Missouri in 1942 Country Number of Number of County Oil Wells Gas Wells Dry Andrew.......... Atchison.......... I Bates............ 2 6 Caldwell.......... I 3 Cass............. I Clinton........... I Holt............. I Jackson.......... I I Knox............ I Nodaway......... I Platte............ 4 4 Ray.............. 5 Sullivan.......... I Totals.......... I 7 28 Otherwise drilling in Missouri was uneventful, with a total of only 36 Completions, of which one was a very small oil well, Seven were small gas wells and 28 were dry holes. The total footage drilled was 24,7541/2 ft., of which 14,0281/2 was by cable tools and 10,726 ft. by rotary. Twelve of the dry holes were drilled into Mississip-pian or older beds. Table I gives a summary of activities by counties.

Jan 1, 1943

By Frank C. Greene

The principal event in the development of oil and gas in Missouri in 1942 was the drilling of the Cities Service Oil Company's No. I Jim Cook, in the northwest corner, NW. 1/4 sec. 32, T. 65 N., R. 39 W., Atchison County, in the northwest corner of Missouri. This well, not yet completed, bailed several barrels of free oil in about 27° Baume from a sand called the Bartlesville by those in charge, at a depth of 1450 ft. The well is on a block of leases obtained after the area, which is covered by several hundred feet of glacial drift, had been prospected by core drilling. Earlier in the year the same company drilled a well on the Glen Gray farm in the southwest corner, SW. 1/4 sec. 29, T. 65 N., R. 39 w., to a depth of 2427 ft. in the Hunton lime with a rotary drill. Oil stains in this hole led to the drilling of the second well. Table i .—-Wells Drilled for Oil and Gas in Missouri in 1942 Country Number of Number of County Oil Wells Gas Wells Dry Andrew.......... Atchison.......... I Bates............ 2 6 Caldwell.......... I 3 Cass............. I Clinton........... I Holt............. I Jackson.......... I I Knox............ I Nodaway......... I Platte............ 4 4 Ray.............. 5 Sullivan.......... I Totals.......... I 7 28 Otherwise drilling in Missouri was uneventful, with a total of only 36 Completions, of which one was a very small oil well, Seven were small gas wells and 28 were dry holes. The total footage drilled was 24,7541/2 ft., of which 14,0281/2 was by cable tools and 10,726 ft. by rotary. Twelve of the dry holes were drilled into Mississip-pian or older beds. Table I gives a summary of activities by counties.

Jan 1, 1943

By MARK H. LAMB

(Canal Zone Meeting, November, 1910.) THE recent growth of a sentiment among cyanide-plant designers against the use of gravity-stamps for the crushing preliminary to cyanidation may be said to date from the almost simultaneous perfection of the ribbed tube-mill liner and of the tall, air-agitation tank. The first step in the resulting change of practice was the universal adoption of the tube-mill for fine-grinding and the use of coarse screening oil the battery. This was the beginning of the surrender of supremacy by the gravity-stamp ; since merely the single fact that it was a more economical machine for crushing fine had retained it in favor as compared with ball-mills, rolls, or steam-stamps. The surrender, however, is not yet complete. It is the universal practice to use rolls where a relatively small tonnage is to be crushed coarse, as, for example, when coarse concentration is included in the plan of treatment. Power, attendance, repairs, and first-cost are smaller for the rolls, under such circumstances, than for stamps; and it is becoming daily more apparent that, with no concentration to provide for, the use of rolls and tube-mills, without the complication of trommels and elevators required by concentration, is rapidly gaining favor in the eyes of the leading designers. The next step was the use of the rapid-running Chilean mill between the gravity-stamps and the tube-mill, which again narrowed the field of operation of the gravity-stamp while radically widening its screen-aperture. Such a combination of stamps and Chilean mill offers advantages when fine concentration is necessary, since the reduction in the Chilean mill call be adjusted easily and governed by varying the screen-mesh. But even concentration is now looked at askance. One of the leaders of this metallurgy has abandoned the separation and

Jul 1, 1910

By H. M. Otte, A. L. Esquivel

A new leasl-squares method is Presented for determining lattice parameters of hexagonal or tetragonul structures. The method is adapted for use on electronic computers and involves a reiterative procedure. The correction factor employed raries linearly with the lattice parameter, a (determined from the Brag, angle). In contrast, Cohen's method and recent modifications of it use a correction factor that varies incersely as the squure of the lattice paramneter, a. While the recent modifications attempt to improve the precision of the extrapolated lattice parameter, a, (or-cu). by stressing the importance of the weighting factor. the present approach emphasizes the need for choosing the correct extrapolation function. A comparison between the present method (the Linear method) and Cohen's method indicates that the Linear method may be more appropriale in certain cases. through a priori no critertion appears to he available for making a chorce between the methods. The size of hexagonal and tetragonal crystal lattices is determined by two parameters, a, and c,. Although in principle the two lattice parameters can be determined independently from reflections for which h - k = 0 and 1 = 0, respectively, in practice this may be inconvenient (because of the angular positions at which these reflections may occur) or not easily possible (because of low intensity). Furthermore, if a high precision or accuracy is required, the limited number of reflections of this type available, particularly in the high-angle region, is not sufficient for the necessary corrections (mainly due to absorption) to be determined with accuracy. Several methods1-7,11-13 have been proposed employing all reflections, to obtain the optimum values, a. and co, either by a trial and error procedure or a least-squares fit. Of the latter method, cohen's5 is the best known one since it provides explicit expressions for the optimum a. and c,. However, Cohen's method is only strictly valid if an extrapolation function is used that varies linearly with l/a2 or lie2 (see Section 3), a requirement that does not appear to be generally appreciated. On the other hand, all the better known and more widely used A recent trial and error method was proposed by Massalski and King8,7 who computed extensive auxiliary tables of axial ratios vs the functions A = [(4/3)(h2 + hk +k2) + l2+(a/c)2] and C = A(c/a)2 used in computing a and c values from the observed Bragg angles. These values of a and c were then plotted against a function which permitted linear extrapolation. As a criteria; for the "optimum" values, Massalski and King rely upon a visual fitting of the line through points representing reflections of low 1-index points to compute the extrapolated value of ao and high 1-index reflections to obtain CO. The successive computations and graphical plotting required to reach the "optimum" value are quite lengthy and tedious even on a desk calculator and no quantitative assurance is obtained of having in fact selected the optimum value.* If the method of Massalski and King is used on an electronic computer, then their published tables become redundant and a least-squares fit becomes a natural selection for the choice of optimum values. Such an approach will be called the Linear method. For work now in progress on the effect of certain physical variables on the lattice parameters of hexagonal crystals, it has become essential to determine the confidence limits of small changes in the lattice parameters. Since extrapolation functions that varied linearly with a and c actually also appeared to vary linearly with l/a2 or l/c2 when tested against published as well as our data, a comparison of Cohen's method and the Linear method was considered desirable (Sections 3 and 4). For the latter method an electronic computer was required since a reiterative procedure to obtain the optimum ao and co values had to be employed. The purpose of this paper is to describe the principles of the Linear method, illustrate its application, and compare it with Cohen's method. 1) THE LINEAR METHOD The standard practice in obtaining the lattice parameters in the Debye-Scherrer method is to

Jan 1, 1965

By W. J. Reagan

In a study of the life of ingot molds, it is essential to eliminate all of the variables. In the commercial manufacture of steel this is almost an impossibility. In this study many of the variables have been eliminated, and because of the unusually consistent furnace practice, with small variations in the type of steel manufactured, and a similar type of mold design for all ingot sizes, it is possible to determine with some degree of accuracy the cause of variations in ingot-mold life. All of the ingot molds in this study were used in the production of basic open-hearth killed steel with chemical analyses within the following range: C, 0.50-0.85 per cent; Mn, 0.60-0.80; Si, 0.20-0.30; S, 0.04 max.; P, 0.04 max. All ingot molds were of the closed-bottom type and used for bottom casting only. None of the molds in the study failed from cutting of the sides due to top casting; in fact, on only rare occasions are any molds used for top casting. The general type of this mold is shown in Fig. 1. All sizes have rather a heavy band of metal, about 6 in. wide, at the top to give mechanical strength at this point, and all have cast lugs. Cross sections of the various sizes from top and bottom sections are shown in Fig. 2. Ratios of wall thickness to ingot weight, ratio of ingot diameter to ingot length, and other figures of interest are shown in Table 1. In the majority of cases, the cause of failure in this type of mold is due to heavy fire cracking on the "flats" at a point from 3 to 6 in. from the bottom radius of the mold. Fig. 3 pictures this type of failure. The start of failure at these points usually begins with a very small section of the interior surface becoming involved. As a rule, a section of 1 or 2 sq. in. is the first noticeable indication that mold failure is taking place. Gradually the small section increases until a sizable cavity develops, causing a protuberance on the bottom of the ingot, which eventually becomes too large to be stripped. The mold is then removed from service. At the time of failure, this cavity often reaches a size of about 5 sq. in. and about 1/2in. deep. Sometimes cavities are found on only two or three sides and at other times all twelve sides appear to be invoIved.

Jan 1, 1937

By PAUL P. ZElGLER

Rapid growth of the aluminum industry continued through 1948 with an acute shortage of the metal in all forms marking the year. Estimates based on shipments made during the first nine months indicate that, in 1948, the industry shipped more than two billion pounds of aluminum products or roughly four times the amount shipped in the greatest peacetime year prior to the war. The rapid expansion of the aluminum industry is particularly reflected in the production of sheet. Last year, the industry as a whole shipped an estimated 40 per cent more sheet than was produced in the peak war year of 1944.

Jan 1, 1949

By Walter Kauenhowen

The crude-oil production of Germany without Austria during 1938 amounted to 3,864,518 bbl., representing an increase of 21.7 per cent over the 3,173,373 bbl. produced in 1937. Adding the Austrian production, the crude-oil production of the new German Reich totaled 4,259,717 bbl. during 1938, representing an increase of 25.3 per cent compared with the respective figures of the previous year. According to published official data, and using a conversion factor of 1 metric ton equaling 7 bbl., the oil production of Germany in 1938 was as shown in Table 1. A semiofficial publication1 states that the program of the crude-oil industry for the second year (1938) of the four-year plan was successfully accomplished. According to the same source, new drilling developments at the following localities were promising: Reitbrook near Hamburg, Heide in Holstein, Eicklingen-Sandlingen near Celle, Steimbke near Nienburg, Worms in the Rhine Valley, Gifhorn near Braunschweig, Mölme near Oberg, and at other places. The drilling activity for oil is illustrated by the figures in Table 2.

Jan 1, 1939