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By John Bell

Aim of Rock-Crushing Experiments THE aim of the laboratory experiments described in this paper was twofold: 1. To measure as accurately, as possible the maximum amount of crushing that can be effected by 1 hp. acting for 24 hr., by the two proposed methods for measuring the amount of crushing, namely: (a) by Rittinger's method; (b) by Stadler's method, based on Kick's law. 2. To show, if possible, that by one of these methods, the amount of crushing produced by 1 hp. in 24 hr. is a constant amount throughout a wide range in the diameter of the piece crushed, and that by the other method, the amount of crushing is a variable quantity over the same range of diameter; or else show that neither of the proposed methods for measuring the amount of crushing indicates a fixed relation between power and crushing and consequently a new method for computing this amount will have to be found to permit the establishment of a law of crushing. Experimental Methods Testing machines, calorimetric methods and commercial. types of rock-crushing machines were considered with reference to their value for measuring power used in crushing. The following electrically driven crushing machines, installed and available in the McGill Ore-dressing Laboratory and which had been used in previous rock-crushing tests, on the whole seemed especially suited to the investigation: (1) Comet "A" crusher; (2) 7 by 9-in. Dodge crusher; (3) 10 by 16-in. rolls. In later tests a 3 ½ -ft. Huntington mill was used.

Jan 2, 1917

By R. P. Fischer

A large production of vanadium during the war helped Germany to meet her critical requirements for the ferroalloy metals. Vanadium was needed not only in the ordinary high-speed too1 steels, but in other as a substitute for chromium, nickel, and molybdenum, which were scarce. Lacking a source of vanadium ore, however, the vanadium was obtained as a by-product of the steel industry—va-nadium-bearing pig iron smelted from iron ores containing about o. I per cellt V was blown in converters to yield vanadium-rich slag, from which vanadium was recovered by chemical treatment. The production capacity obtained was said to be about 6,500,000 lb. of vanadium a Year. Although the general Processes of Preparing vanadium-rich slags as well as the recovery methods described herein are known, some of the details presented may be of interest to both the American steel industry and the vanadium producers. No adequate data on the cost of the vanadium produced in Germany are known, but it seems likely that the cost exceeds the commonly quoted domestic price of about $1.10 per pound of contained VzOa. Information on the German vanadium production was obtained by a team of geologists from the Geological Survey* United States Department of the Interior, during investigations in May and June 1945 of the German utilization of low-grade raw materials. These investigations were sponsored by the Chief of Engineers, War Department. It is a pleasure to acknowledge the aid obtained from Messrs. H. C. Smith and J. D. Dickerson, investigators assigned to the Army Ordnance section of C.I.O.S., and Mr. C. F. Park, Jr., of the Geological Survey team. The data on vanadium recovery from iron ores were obtained from the Kaiser Wilhelm Institut fiir Eisenforschung, the Hermann Goring steel plant at Watenstedt, and from notes made by other investigators at other German steel plants. Preparation of Vanadium-rich Slags Most German iron ores contain only about 0.1 per cent vanadium, or even less, but some of the scandinavian iron ores available to the German iron industry in the past contain a little more than 0.1 per cent. In general German practice of vanadium recovery, nearly all of the vanadium in the ore goes into the pig iron, which is blown in the Thomas converter, yielding a slag containing about I per cent V. This slag is remelted, the vanadium again going with the iron, which is again blown in a converter, yielding a slag that averages about 10 per cent V. This slag is treated at special chemical plants, by the process of a sodadizing roast, water leach, and acid precipitation of vanadium oxide. The Herman Goring steel plant at Watenstedt used the low-grade Salzgitter iron ores, the average composition of which is shown in Table I, column I. The acid and basic iron produced in the blast furnaces contained about 0.3 per cent V. A Thomas

Jan 1, 1948

By R. P. Fischer

A large production of vanadium during the war helped Germany to meet her critical requirements for the ferroalloy metals. Vanadium was needed not only in the ordinary high-speed too1 steels, but in other as a substitute for chromium, nickel, and molybdenum, which were scarce. Lacking a source of vanadium ore, however, the vanadium was obtained as a by-product of the steel industry—va-nadium-bearing pig iron smelted from iron ores containing about o. I per cellt V was blown in converters to yield vanadium-rich slag, from which vanadium was recovered by chemical treatment. The production capacity obtained was said to be about 6,500,000 lb. of vanadium a Year. Although the general Processes of Preparing vanadium-rich slags as well as the recovery methods described herein are known, some of the details presented may be of interest to both the American steel industry and the vanadium producers. No adequate data on the cost of the vanadium produced in Germany are known, but it seems likely that the cost exceeds the commonly quoted domestic price of about $1.10 per pound of contained VzOa. Information on the German vanadium production was obtained by a team of geologists from the Geological Survey* United States Department of the Interior, during investigations in May and June 1945 of the German utilization of low-grade raw materials. These investigations were sponsored by the Chief of Engineers, War Department. It is a pleasure to acknowledge the aid obtained from Messrs. H. C. Smith and J. D. Dickerson, investigators assigned to the Army Ordnance section of C.I.O.S., and Mr. C. F. Park, Jr., of the Geological Survey team. The data on vanadium recovery from iron ores were obtained from the Kaiser Wilhelm Institut fiir Eisenforschung, the Hermann Goring steel plant at Watenstedt, and from notes made by other investigators at other German steel plants. Preparation of Vanadium-rich Slags Most German iron ores contain only about 0.1 per cent vanadium, or even less, but some of the scandinavian iron ores available to the German iron industry in the past contain a little more than 0.1 per cent. In general German practice of vanadium recovery, nearly all of the vanadium in the ore goes into the pig iron, which is blown in the Thomas converter, yielding a slag containing about I per cent V. This slag is remelted, the vanadium again going with the iron, which is again blown in a converter, yielding a slag that averages about 10 per cent V. This slag is treated at special chemical plants, by the process of a sodadizing roast, water leach, and acid precipitation of vanadium oxide. The Herman Goring steel plant at Watenstedt used the low-grade Salzgitter iron ores, the average composition of which is shown in Table I, column I. The acid and basic iron produced in the blast furnaces contained about 0.3 per cent V. A Thomas

Jan 1, 1948

By J. S. Levine, M. Prats

Several methods are available for calculating the performance of solution-gas-drive reservoirs from the PVT properties of the oil and from the relative permeability and other properties of the formation. These methods require a number of simplifying assumptions. The present method of computation has made use of a high-speed computer to solve simultaneously the nonlinear partial differential equations that describe two-phase flow by solution-gas drive in order to calculate the performance of a reservoir. Some of the results obtained by the nonlinear partial differential equation solution are compared with those obtained with an approximate method, which has been called the semisteady-state solution. The pressure and saturation profiles from the wellbore to outer boundary calculated by the two methods are compared for one constant-terminal-rate case and two constant-teminal-pressure cases. The agreement in these profiles, as well as in the values of average reservoir pressure and cumulative recovery, leads to the conclusion that, for most engineering calculations, the semisteady-state method will give a reasonable approximation to the numerical solution of the differential equations describing solution-gas drive. An unfavorable (as regards ultimate oil production) set of relative permeability curves was used in the calculations in the belief that the effect of the parameters which were studied would be emphasized to a greater degree. Furthermore, the reservoir was assumed to be completely homogeneous, and these results should not be considered applicable to any other type of reservoir. Gravity effects are not considered. The absolute permeability was varied from 25 to 0.5 md. At an economic limit of 2 B/D, the recovery for a 25-md reservoir is about 1.8 times as great as that for a 0.5-md reservoir. The effect of permeability on the producing gas-oil ratio is minor. Once PVT properties of the oil and the relative penneability properties of the reservoir are fixed, the pro- during gas-oil ratio is found to be a function of the fraction of oil recovered. Well spacings of 10, 40 and 80 acres were considered. For the assumed homogeneous-reservoir properties, the effect of spacing on recovery at an economic limit of 2 B/D was very slight. Certain dimensionless groups can be used to extend the results to other fields having different penneabilities, spacings, reservoir thicknesses, well radii and porosities, so long as the PVT and relative permeability properties are similar to those used in this paper. INTRODUCTION An important aspect of reservoir engineering is the prediction of the performance of the reservoir based on the limited information normally available early in the life of a field. Usually, soon after a field has been discovered, it is necessary to decide upon the spacing to be employed and the production program to be used for most efficient utilization of reservoir energy. Where these decisions have not been dictated by legal or political considerations, they have frequently been based on experience factors which indicate that two fields with similar characteristics will probably have similar performances. To the extent that the industry has been successful in economically exploiting oil reservoirs, this rule-of-thumb method has been found to have merit. A large amount of theory has been developed with which it is possible to predict the performance of a reservoir by using certain known properties of the oil and the formation. Because of the difficulties of the mathematics involved for a drainage area having square or rectangular boundaries, the problem usually has been simplified and idealized by assuming each drainage area to have radial symmetry and the field to be represented by a number of these drainage areas. Muskatl was one of the first to formulate the theory for two-phase flow and to solve the equations for a few cases by numerical integration, using the relatively slow means of computing available at that time. His equations describing

By G. W. White

Over the past several years, the steady progress of gas lift from a mysterious art into a developing science has been traceable through the many fine papers that have appeared in Journal of Petroleum Technology. Consequently, this magazine has rightly become a standard for the serious students of gas lift all over the world. The following discussion is offered in a sincere attempt to accurately present certain topics covered in the subject paper in the light of acknowledged state of the art procedures. INSTALLATION DESIGN The first point to be questioned is the author's installation design, beginning with Eq. 6. The use of 1,200 psi in the spacing equation instead of the 1,275 psi noted as available seems, at first glance, to be a simple arithmetic error. Upon further examination, it appears evident that both this 75 psi plus the 100-psi safety factor must be subtracted from available kickoff pressure because of conditions imposed by the characteristics of the ASC valve (see Fig. B-1). Pressure-charged valve design is incorrectly penalized by spacing the first valve using only 1,100 psi. The use of such a high back-pressure makes it appear that a typical ASC installation would require no more valves than a comparable conventional valve installation. Using a value of 100-psi tree pressure, the well could be valved to 11,000 ft very conservatively with seven pressure-operated valves, but would still require 11 ASC valves. The use of 400-B/D spacing gradient for a 140-B/D rate is not an accepted practice using precharged valves. The author would have done well to note the advantages to be gained by reducing the 500-psi tree pressure, which is clearly explained by Beadle, Harlan and Brown.' In Step 1 of Part III of the continuous flow discussion, the author incorrectly applies the Poettmann and Carpenter curves.2 Item 2 is an incorrect statement. An excellent reference on this point is the paper by Baxen-dell and Thomas.' VALVE MECHANICS The next topic relates to the mechanics of precharged valves. Eq. 2 for the ASC valve can be used to describe the condition of equilibrium, wherein the valve is closed with opening pending. When this equation is used to determine relative values of casing, dome and tubing pressure with conditions approaching the transition value, some strange results are obtained. The following uses the author's symbols and values given on page 689. Fig. B-1 shows the condition that exists at the moment an ASC valve has been uncovered during the unloading process (Condition I). The obvious result is a locked condition. The basis for the curve is shown on the figure which includes 1,000 psig casing pressure to uncover the valve. If injection gas is not bled off the casing until the pressure is decreased by an amount exceeding the stabilizer discharging valve pressure, upward adjustment of the casing pressure is mandatory for the valve to open and unloading operations to continue. In Condition I the dome pressure exceeds the casing pressure by 20 psi, and the tubing pressure required to open the valve is 1,212 psig. This tubing pressure would not exist under the assumed conditions. In Condition I1 the casing pressure is increased to the dome pressure, and the tubing pressure required to open the valve is 1,102 psig. It is apparent that the casing pressure must be increased to a value exceeding the dome pressure before unloading operations could continue. In Condition I11 a maximum casing pressure of 100 psi (stabilizer charging valve set pressure) above the dome pressure is reached, and the tubing pressure required to open the valve is 549 psig. The author's statement after Eq. 5 that "the minimum tubing pressure required to open an ASC valve is equal to the casing pressure at depth less the transition pressure of the valve" is incorrect except for Condition I11 only. Otherwise, the equation is invalid.

Jan 1, 1965

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

By William R. Webster

An investigation has been made of 500 samples of universal and sheared plates of basic Bessemer and basic open-hearth steel manufactured by the Pottstown Iron Company, the carbon-limits being 0.07 to 0.18 per cent. Through the courtesy of Mr. W. H. Morris, President, I am able to lag before the Institute the results of these tests. The samples tested were all taken from the finished material, and the chemical determinations were made on drillings from the broken test-pieces, which were sent to the chemist without giving him the heat-numbers. The results are such as to encourage me to keep on with the work, and, if possible, to have it carried out on other steels. It is kith this view that I now offer my tables in their incomplete form. My first table mas constructed by grouping the tests according to chemical analysis in various. ways, and making a rough tabulated statement, from which the ultimate strengths were worked out and carefully compared with the actual results of the tension-tests. From data thus obtained, one table after another was worked out, and by this method of "cutting and trying" I finally arrived at the results which I now present in Table I. (p. 771). I do not claim absolute accuracy, but my approximations have proved to be so close that the figures are practical data for current use at the works. The indications are that a pure iron, without carbon, phosphorus, manganese, or silicon, if it could be obtained, would give 38,000 pounds ultimate strength. This is assumed as a base, and to it is added the effect of each of the above elements, as explained below. The upper part of Table I. gives the ultimate strength due to carbon and phosphorus, and is the same for both basic Bessemer and basic open-hearth steels. The lower part gives the increase in ultimate strength due to manganese. By adding this to the amount obtained from the upper part, we have the ultimate strength of basic Bessemer

Jan 1, 1893

By T. Egleston

The origin of gold both in placer deposits ancl in veins, and especially the origin of nuggets, has been the subject of repctated discussions and investigations, which have been recently brought to my attention by several extremely interesting specinlens sent to me for examination, and mare especially by the one exhibited at the meeting of the Institute in February, 1880.* In the year 1874 I made some exan~inations of the hydraulic mines of California, and was very nluoh struck with the distribution of the gold throughout these deep placers, which were almost invariably poor on'the surface, while gradually growing richer towards the bedrock. The constant presence of fossil wood, and the large quantity of organic matter contained even low down in these beds, was also remarkable. Not being satisfied with the various theories advanced to account for the formation of these deposits, I began an investigation early in the pear 1879 on the conditions of solubility of gold and the causes of the loss in working gold ore in a large way. The researclles which I have undertaken show that gold must be considered a soluble rather than an insoluble metal, and that the conditions of solution are such as will be found anywhere where gold is likely to occur, and the solution may take place even under the ordinary circumstuncee of surfiace drainage, and may be going on freely even where the presence of gold has never been suspected, and that there are causee enough in nature to produce the solution of the gold in sufficient quantities to account for all the phenomena of both the vein and placer formations. The general theory with regard' to the formation of these placer deposits and nuggets has been that they were the result of the deatruction of pre-existing. vein-matter, which does not accord with the fitcts as sholvn in the deep placer deposits. The gold in such case would be distributed in layers of unequal richness throughout

Jan 1, 1881

By AIME AIME

The history of development of oil and gas areas in the Kirkuk field. Iraq, from the commencement of drilling in 1928 to the end of 1945. is set forth in Table I. The production of the Kirkuk field from the commencement of the use of the Iraq Mediterranean pipe line to the end of 1945 is listed at the end of Table I.

Jan 1, 1946

By D. W. Duncan, A. Bruynesteyn

An ore containing chalcopyrite was microbiologically leached in 6 ft columns at particle sizes ranging from -2 +1 ½ inches, to -3/8 + 3/16 inches. The rate of leaching increased exponentially as the particle size decreased. The controlling factor was the active leaching volume made up of the particle surface area and the depth of penetration of the bacteria and leach liquor into the particle. This volume became an increasingly larger part of the total volume as the particle size decreased. The sample under test leached poorly at larger particle sizes and it was calculated that under commercial conditions, it would produce at best a pregnant solution containing 100 mg/l (0.2 lb/ ton) of copper per 100 ft of dump height.

Jan 1, 1974

By T. K. Redden

Protective coatings based on the formation of a surface coating of nickel aluminide (NiAl) were applied to the nickel-base superalloys IN 100, SEL 15, and U-700. Coated specimens were exposed to an oxidizing environment at temperatures between 1600 and 2200 F for times up to 1000 hr. The oxidation resistance and stability of the coating were evaluated by weight gain measurements, metallographic examination, and X-ray diffraction study of surface oxides and coating. The composition of the coating and diffusion zone was determined by electron microprobe traverse of samples before and after high-temperature exposure. Intermediate phases formed in the coating and diffusion zone were identified by X-ray diffraction in situ and after electrolytic extraction. The outer coating was found to consist of the inter-metallic compound, NiAl, while the diffusion zone contained MC, M23C6 or M6C carbides, and a phase in a matrix of NiAl + Nidl. Oxidation resulted in formation of an A1203 n'ch scale containing some Tz02. Depletion of aluminum during oxidation resulted in degradation of the outer coating to Ni3Al and the nickel alloy matrix. Diffusion of aluminum into the base metal was found to be slight and did not influence coating life significantly. The o formed in the diffusion zone during coating decomposed during elevated-temperature exposure to form stable carbide phases characteristic of the base metal. Diffusion zone phase changes were found to have no effect on the life of the aluminide coating in the oxidizing envzron?nent. THE oxidation resistance of many high-strength nickel-base superalloys is inadequate for extended exposure at temperatures above about 1600°F. In addition, some applications for these materials require that they be exposed to environments containing sulfur compounds and sodium salts which can cause surface attalk known as sulfidation or hot corrosion. In order to provide the necessary corrosion resistance to the high-strength alloys, protective coatings based on an aluminizing process have been developed. These processes, usually based on a pack cementation technique, result in the formation of a NiAl-rich outer coating layer either during the coating process or by a subsequent diffusion treatment. The performance of the aluminide coatings is affected by interactions between the coating layer and the base metal both during the coating process and during subsequent exposure at elevated temperatures. Knowledge of these interactions is required to guide the development of coatings capable of longer life and improved reliability. Goward et al.' recently reported the metallurgical factors which influence coating per- formance on MAR-M200. The present work is concerned with correlating the interactions and performance of coating compositions on several representative materials. EXPERIMENTAL PROCEDURES Materials. Three cast nickel-base superalloys which are used for turbine buckets in air-breathing engines were studied: IN 100, U-700, and SEL 15. Their chemical compositions are given in Table I. The alloys were vacuum-induction-melted and cast to slabs approximately 0.3 in. thick from which rectangular specimens 0.25 by 0.5 by 1 in. were machined. Coating Procedures. The machined specimens were coated by CODEP processes which were developed at the author's laboratory. These are based on pack cementation in various media to deposit either aluminum or aluminum in combination with titanium. The coating process which deposits only aluminum is designated CODEP-C, while the CODEP-D process deposits titanium in combination with aluminum. The CODEP-D process was applied only to IN 100. Both CODEP processes are applied at 1950" or 2000°F for 4 hr without need for a subsequent diffusion treatment. An outer coating about 1 mil in thickness is produced by these processes. Test Procedures. Coated specimens were exposed to static oxidation for periods ranging from 24 to 1000 hr at temperatures of 1600" to 2200°F. Terminal weight gain measurements and visual examination were used to evaluate oxidation resistance. including oxide spalling and coating failure. Both as-coated and exposed specimens of each alloy were studied by metallographic examination, electron microprobe analysis (EMA), and X-ray diffraction analysis either of the exposed surfaces or of phases extracted from the coating and diffusion zone. RESULTS As-Coated Condition. The microstructures of as-coated conditions were generally similar, irrespective of base materials or the particular coating process. They are typified by IN 100 coated by CODEP-D as shown in Fig. 1. The predominately single-phase outer layer, area A, Fig. 1, was identified by X-ray diffraction as the intermetallic compound NiA1. The NiAl zone extended inward to the original base metal interface. The diffusion zone, area B, Fig. 1, included carbide phases, a lamellar phase oriented perpendicular to the base metal surface, and a matrix phase consisting of a mixture of NiAl and Ni3Al. The phases in the diffusion zone were electrolytically extracted using a 10 pct HCl in methanol solution at approximately 1.3 amp per sq cm. The extracted phases were found to be M6C, MC, or M=C6 carbides and o as shown in Table I1 for each of the alloys. The d spacings from a typical diffraction pattern are

Jan 1, 1969

By Henry P. Ehrlinger, James C. Bradbury

Tripoli is a naturally occurring, very finely divided form of silica found chiefly in some midwestern and southeastern states and used commercially as fillers and abrasives. Definitions Tripoli is a microcrystalline, finely particulate, more or less friable form of silica that appears to be the product of leaching of siliceous limestone or calcareous chert. The term was originally applied to a deposit near Seneca, Mo., that resembled material of that name found near Tripoli in North Africa (Hovey, 1894). The two deposits were subsequently found to have different physical characteristics -the North African tripoli, now called tripolite, is a diatomite, composed of the siliceous skeletons of microscopic marine plants called diatoms, and the Missouri tripoli contains no diatom remains; the term tripoli, however, continued to be used for the Missouri material and is now applied in a general way to most silica deposits similar to it in characteristics and geologic origin. In commercial trade tripoli is commonly understood to designate material from the Missouri-Oklahoma field; silica from southern Illinois, the other major producing area, is referred to commercially as amorphous silica. Each term, however, may be used commercially for material, regardless of place of origin, that has the characteristics or uses commonly ascribed to the material from one or the other major producing area. For example, in the commodity price listings, Engineering and Mining Journal routinely lists under Tripoli, prices "f.0.b. Elco, III." and "f.0.b. Seneca, Mo., and Rogers, Ark.," and under Silica, amorphous, prices "f .o.b. Ill.," and "f .o.b. Dierks, Ark." Amorphous silica, the commercial designation given to southern Illinois tripoli, is, like the term tripoli, a misnomer. Mineralogically, the southern Illinois deposits are composed of microcrystalline quartz, and no amorphous material has been detected during X-ray and scanning electron microscope investigations (Leamnson, Thomas, and Ehrlinger, 1969; Thomas et al., 1970). Soft silica is another term that has been applied to Illinois and Tennessee tripoli, presumably to distinguish it from the more compact Missouri material. It has also been used in the ceramic trade to distinguish tripoli from "hard" silica, or silica flour, produced by pulverizing silica sand (Heinz, 1937). Rottenstone, produced commercially in Pennsylvania, is similar to tripoli in that a major constituent is finely particulate silica, and its uses are much the same as those of tripoli- as abrasives and fillers. The origin of rottenstone also is similar to that of tripoli-decomposition of a siliceous sedimentary rock. The parent rock is defined as a siliceous limestone (Gary, McAfee, and Wolf, 1972; Thrush, 1968) or as shale (personal communication). Heinz (1937) quotes a brief statement describ-

Jan 1, 1975

By Earl Oliver, J. B. Umpleby

It is believed that in connection with the study of unit operation by the Petroleum Division of the A. I. M. E. a review of the simple principles of unit operation would be helpful. To that end, the following discussion is submitted. It is not to be considered in any sense as the conclusion of the committee, but rather as material submitted for its consideration and represents at this time only the viewpoints of its authors. Growth of the Oil Industry In 70 years the oil industry has grown from a single well on Oil Creek, Venango County, Pennsylvania, producing 25 bbl, per day, to more than 400,000 wells scattered over five continents with a daily output of 4,000,000 bbl. In that time petroleum has expanded from its simple use as a medicine in a few localities to a multitude of diverse uses in homes of every country the world over. During those years the oil fields of the United States have produced two-thirds of the world's output and have shipped their excess production into almost every country. In those years several hundred thousand good wells in the United States declined into small ones and depleted shallow deposits gave way to deep zones; so that the United States crude oil industry gradually changed from one of low cost production to one of higher cost. Throughout its entire life it has labored under two serious economic disadvantages, namely, constantly recurring periods of demoralization through overproduction, and competitive development methods that are wasteful. Development of Foreign Competition During the transition from low to higher cost production in the United States, events even more significant were taking place in foreign lands. Jungles were tamed and deserts conquered. Oil deposits were found and developed until, in the words of Sir John Cadman, "the globe is now drenched with a commodity which, although necessary to life, involves but an irregular and sometimes meager expenditure of life in its

Jan 1, 1930

By J. C. Allen, E. V. Herring

CHILE EXPLORATION CO's. oxide plant at Chuquicamata, the largest of its kind, started in 1915 with initial operations at the rate of 10,000 tons of ore per day. Anaconda Copper Mining Co. acquired the controlling interest in 1923 and in the next few years modernized the plant and mine, extending operations to a nominal capacity of 490 million lb of electrolytic copper yearly by 1942. Plant production averaging 495.7 million lb of copper per year was maintained for the eight-year period extending from 1941 to 1948 inclusive. During the World War II production reached its highest level when in 1944 the output was 531.8 million lb. The maximum production for any one month was 49.6 million lb, achieved in May 1947. E. A. Cappelen Smith, consulting metallurgist for M. Guggenheim's Sons, worked out the first process for the treatment of Chuquicamata copper oxide ore about 1913, and directed a staff of 20 young engineers operating a pilot plant at Perth Amboy, N. J., on three shifts for an entire year. The copper is extracted from the oxide ore by a hydro-metallurgical treatment described in detail by T. A. Campbell in AIME Transactions, Vol. 106, Copper Metallurgy, 1933. The Oxide Plant is divided into five main operations as follows: (1) Crushing, (2) Leaching, including dechloridizing and sulphur dioxide treatment, (3) Tailing disposal, (4) Electrolytic precipitation, (5) Smelting and melting. Crushing The present Primary Crushing Plant has been in operation 25 years, during which time 4,342,112 cars of 70 tons net capacity have passed through the dumpers. The ore as received from the mine is frequently blocky and up to 5 feet in section. It is reduced to 9-in. size by two 60-in. gyratory crushers, and transported to the east and west ore bins by 60-in. conveyors. In the secondary crushing operation the ore is first reduced to 2 to 3-in. size by five standard 7-ft cone crushers and two No. 10 gyratories. This product is then reduced to 3/8-in. size by fifty-two 48-in. vertical Symons disc crushers and is transported by belt conveyors to the loading bridges from which it is charged° into the leaching vats. Conveyor belt No. 14 which serves the eight vats in the east section of the leaching plant has transported over 125 million tons of ore, which is a record for any type of conveyor. This 60-in. belt travels at a speed of 600 fpm and carries loads up to 5500 tons per hr. Leaching The ore is leached in 14 vats, averaging 13,500 short tons net capacity each. These vats are lined with a natural mastic which adequately resists the sulphuric acid leaching solutions. The leaching process as presently conducted comprises soaking the ore with successive volumes of leaching solution and spent electrolyte and withdrawing successive volumes of enriched solution from the vat to a total of approximately 3.2 million gal. The first 1.6 million gal of this volume withdrawn is called strong solution and contains about 35 parts of copper per 1000. The balance of 1.6 million gal subsequently withdrawn is stored in a

Jan 1, 1952

By J. N. Ong, J. P. Ratledge, J. H. Boyce

SINCE German operators opened the Tsumeb mine in the early 1900's, continuous operation has been interrupted only by enforced shutdowns during two world wars and the depression of the 1930's. Original metallurgical practice was blast furnace smelting. This was applicable only to low zinc ore, leaving large tonnages of high zinc ore to be stockpiled on the surface. A gravity concentrator using tables, buddles, and jigs operated for several years, but differential flotation of the ore did not get beyond the experimental stage. When the property was put up for sale by the South African Custodian of Enemy Property there was an estimated 434,000 tons of ore on surface dumps. The dump material, assaying 4.48 pct Cu, 15.8 pct Pb, and 10.9 pct Zn, had become highly oxidized during a stay of many years on the surface. But these dump ores had to be used in evaluating possible metallurgy because the shaft became flooded after the 1940 shutdown and underground ore was unavailable. Many companies examined Tsumeb but quickly lost enthusiasm because of the formidable metallurgical problems presented by the dump ore. However, on the basis of extensive test work, the present company decided that differential flotation would be successful and purchased the property after competitive bidding. Geology and Mineral Association is Complex The Tsumeb mine lies near the northern boundary of South West Africa at an altitude of 4200 ft. The village of Tsumeb is 335 air miles northeast of Wal-vis Bay, territorial port of entry. The orebody is a hydrothermal replacement deposit associated with an irregular intrusion of aplite cutting folded pre-Cambrian dolomite beds. In plan the deposit is a lens of 250x600 ft maximum dimensions. In section the orebody dips 55" south from the surface to 2000 ft, below which there is a reversal in dip to 75" north. Mineralization is localized in the aplite and in the adjoining brecciated dolomite. In the upper levels the ore is largely confined to a single lens, but below the 1890 level massive sulphide ore forms north and south lenses that partially enclose a pipelike body of medium to low grade disseminated ore, part of which is of too poor a grade to mine. Drilling below the 24th, or bottom level, has disclosed that a high percentage of the mineralization from the 3000 to 3300-ft horizons is comprised of copper and lead oxides. The deep oxidation may be local, since it appears due to circulating waters in a major fault cutting the orebody. Tsumeb ranks as one of the highest grade base metal deposits in the world. It is geologically and mineralogically famous for 41 copper, lead, zinc, vanadium, and germanium ore minerals, but its complex mineral assemblage is not attractive to metallurgists. In addition, there is a gradual change in oxidation intensity from the upper levels to the lowest level now operating, which is the 24th. This is well illustrated by the copper minerals. In the upper levels malachite and azurite are predominant, in the intermediate levels chalcocite, and in the lower levels tennantite. Throughout the mine there are sufficient heavy metal soluble salts to activate zinc, and large amounts of depressants are required even for so-called clean sulphide ores. When the same sulphide ore is exposed to prolonged oxidation aboveground, as was the case with the dump ores, reagent requirements become fantastic. Plant Construction First staff members arrived at Tsumeb in March 1947, and by May essential services had been restored and mine unwatering began. In 2 1/2 months company employees built a temporary jig and sorting plant for treating existing dumps to provide a saleable product during high metal prices. Meanwhile, concentrator design and construction was contracted to a South African firm, with subcon-

Jan 1, 1956

By Thomas N. Walthier

Ocean miners seem prepared to commit upwards of $50 million, spread over the next 10 years, to develop a deep ocean capability. More and more large companies, Kennecott, Inco and Tenneco, to name a few, singly or through consortia, are spending money, often big money, to obtain a viable and profitable marine mining industry. Much of the current involvement of the mining industry in the oceans is concerned with either exploration for or engineering studies of manganese nodule deposits and most of it is considered highly proprietary. Thus, the scope of the total effort can only be surmised. The following provide a good indication as to the magnitude of the over-all effort: (1) Hughes Tool Co., Oil Tool Division, announced last March it has been performing engineering studies and ocean surveys (in collaboration with Global Marine, a subsidiary of Tenneco Oil) for the purpose of developing deep ocean mining equipment and techniques. As a result of these studies, Global Marine will build a 35,000-ton prototype deep sea mining ship for Hughes. (2) Deepsea Ventures, Inc. has been "assiduously compiling data on the location. depth, and composi-

Jan 1, 1971

By Eric Jette

THE results of an investigation of the ternary system iron-chromium-ilicon were reported in 1936 by the present authors.1 Partly for the sake of theoretical interest, and partly because of the possible commercial importance of these alloys, the present investigation was undertaken to determine the effect of some of the commoner elements likely to occur, deliberately or otherwise, in such alloys if made on a commercial scale. The elements thus added were carbon, nickel or manganese. The alloys studied were, therefore, parts of quaternary systems. This investigation was concerned primarily with the effect of these additional elements on .the alpha-iron phase and the boundary between this phase region and the alpha plus sigma two-phase region. The sigma phase is a ternary solid solution based upon the compound FeCr. The work was performed mainly by X-ray methods, but a number of microscopic examinations were also made and are reported. While isolated alloys in the composition ranges studied may have been discussed in metallurgical publications, no systematic investigation of any assistance to us was found. Of the earlier work, the investigations on the iron-chromium-carbon system and on the chromium carbides by Westgren and his coworkers,2,3 enabled us to identify the carbide phase. Several articles appeared after the present experimental work had been completed. Lucas and Wintrup4 determined the solubility of carbon ill molten iron-chromium-silicon alloys. Tofaute and his coworkers5,6 have made detailed studies of the iron-chromium-carbon system, which will he referred to later.

Jan 1, 1937

The Institute conducts jointly with the American Society of Civil Engineers, 'American Society of Mechanical Engineers and American Institute of Electrical Engineers, certain activities as listed below, and is joint owner with them if certain properties. United Engineering. Trustees, Inc. When Mr. Carnegie made his gift which made possible a home for the engineering societies, a separate corporation was organized to act as a holding company and to manage the common property. This was long known as the United Engineering Society but the name has now been changed to one which more nearly reflects the real function of the corporation. It holds title to the Engineering societies Building and to various funds placed in its charge and is managed by a Board of Trustees of which three are chosen by each of the four societies, American Institute of Mining and Metallurgical Engineers, American Society of Mechanical Engineers, American Institute of Electrical Engineers and American Society of Civil Engineers, which own equal and undivided interests in the property. The land and building cost two million dollars. The interest of each of the Founders societies, aside from especial trust funds, is now valued at $493,352. The A. I. M. E. trustees are Arthur S. Dwight, J. V. N. Don and George D. Barron. The President of the Board is Francis Lee Stuart and the Secretary, Alfred D. Flinn.

Jan 1, 1929

By C. G. Dunn

Nuclei that are formed during the recrystallization of a grain following plastic deformation generally have orientations that differ from the original. This aspect of recrystallization may be described in terms of orientation changes. It was shown previously, in an investigation on recrystallization in silicon ferrite,&apos; that the observed orientation changes were highly improbable on a chance basis, and that some mechanism must be involved. Analysis showed that the data could be satisfactorily classified into the smaller of two subclasses† of the 36 third-order twin transformations. No attempt was made at that time to classify the data within the special class of 12 third-order twin transformations, although results did indicate a greater probability for some of them to occur. A classification of this type would be more valuable, of course, with more data on orientation changes per old deformed grain. The present work fulfills this condition to some degree and also extends the scope of the investigation to include the effects of original orientation and the amount of plastic deformation. The effect of original orientation is of considerable interest because of the known effects of orientation on plastic deformation, particularly with regard to degree of fragmentation and the formation of deformation bands, and because the orientations produced by deformation should influence the orientations obtained through recrystallization. Barrett and Levenson2 reported that single crystals of iron deformed in the range 82 to 97 per cent could be put into three general classes; namely, crystals in class I maintained a reasonably sharp single orientation, those in class 2 transformed into two distinct orientations, and those in class 3 changed into a large number of major and minor orientations. Something similar would be expected for silicon ferrite crystals, and verification of this for a few cases of types class I and class 2 deformation has been reported elsewhere3 for single crystals of silicon ferrite cold-rolled in the range 10 to 20 per cent. As an example of class 2 deformation, it was shown that a crystal of silicon ferrite cold-rolled in a (110) plane in a <100> direction developed two layers, or deformation bands differing in orientation. When this happens it is possible to etch away one band and leave a single structure for use in studying the orientation changes that occur during recrystallization. when preferred crystal orientations are obtained in recrystallization, it is not particularly necessary to evaluate groups of common orientation, as was done previously (ref. I, Table 6); but an

Jan 1, 1947