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By B. G. Ricketts, A. Kelly, P. A. Beck

The isothermal kinetics (at 200" to 400°C) of subgrain growth and of softening were studied in a 99.997 pct pure Al crystal rolled to 80 pct RA, under conditions where recrystallization did not take place. It was found that the kinetics of subgrain growth and of softening were similar, and that the correlation between subgrain growth and softening was in first approximation independent of the annealing temperature. It has been shown by Heidenreich' by means of electron transmission microscopy and by Hirsch and Kellar2 by means of an X-ray microbeam technique that the crystals of heavily cold-worked polycrystalline aluminum consist of subgrains of approximately 2µ diam, which are slightly disoriented with respect to each other. This substructure is found on cold working at room temperature, without annealing. A preliminary study has been previously published3 of the softening upon annealing at 350°C of a heavily cold-rolled aluminum single crystal. Softening and X-ray line sharpening for such a rolled aluminum crystal were later studied in more detail as a function of annealing time and temperature.4 Perryman5, 6 has studied the recovery of polycrystalline aluminum after cold rolling. By means of phase contrast microscopy he found that the subgrain size increases with the annealing temperature but does not alter very much with annealing time at a given temperature. In the present work further study was made of softening as a function of annealing time and temperature and subgrain sizes were determined by two different techniques in an attempt to find any correlation that may exist between softening and subgrain growth. Subgrain size measurements were made both by the X-ray microbeam technique and by transmission electron microscopy. EXPERIMENTAL PROCEDURE For the X-ray studies specimens were cut from

Jan 1, 1960

NEW MEMBERS The following list comprises the names of those persons who became members during. the period Mar. 10, 1919, to Apr. 10, 1919. AFFLECK, B. F., Pres., Universal Portland Cement Co., 210 So. La Salle St., Chicago, Ill. BENSUSAN, ARTHUR J., The Ouro Preto Gold Mines of Brazil, Ltd., Passagem de Marianna, Minas Geraes, Brazil, S. A. BIERBAUM, CHRISTOPHER H., Cons. Engr., & Vice-pres., Lumen Bearing Co., Buffalo, N. Y . DEWITT, OSCAR E., Geol., Vinegar Hill Zinc Co., 622 North Court St., Platteville, Wis. DOTY, L. C Mine Supt., Bullion Beck & Champion Co., Box C, Eureka, Utah. ESPIE, FRANK F Burma Mines, Ltd., Namtu, Upper Burma, Asia. FOZARD, J. L., Gen'l Supt., Beatson Mines, Kennecott Copper Corpn., Latouche, Alaska. GRANT, BENERE Supt., Bulluhacker Min. Co., Butte Mont. HARDEL, JEAN A., Engr., French Government, 21 Rue du Colonel Moll, Paris, France. JANSSEN, WALTER A., Operating Mgr., Canadian Steel Foundries.Ltd., 120 St. James St., Transportation Bldg., Montreal, Canada. KNOWLES, RALPH Roy, Supt., Radium Plant, The Minerals Recovery Co., 457 So. Elati St. Denver Colo.

Jan 5, 1919

By Charles Mabery

So FAR as the elementary composition of petroleum is -known, it may be briefly stated. Petroleum consists principally of a few series of hydrocarbons, with admixtures of sulfur, nitrogen, and oxygen derivatives in comparatively minute proportions, which may be regarded as impurities to be removed in the preparation Of commercial products. But as each series is represented by many homologs, in the aggregate, crude petroleum is an extremely complex mixture of hydrocarbons and their derivatives. In part, these hydrocarbons individually conform in structure to the system of synthetic hydrocarbons whose structure is well defined and -represented by the typical series CnH2n+2, CnH2n, the series CnH2n-2, CnH2n-4, the members of which have not been sufficiently studied to establish their structure, and the series CnH2n-6 composed of the aromatic group, benzene and its homologs. Hydrocarbons of greater density contained in the portions of petroleum that cannot be distilled without decomposition doubtless have less hydrogen than is represented by these formulas. Since to every hydrocarbon there is a definite temperature, even in vacuum, at which its constituent carbon and hydrogen atoms fall apart, and since for the heavier bodies this temperature is not much above 360° C. in vacuum, it is evident that some other method than distillation must be devised for their separation if anything further is to be learned concerning their individual constitution. CLASSIFICATION OF PETROLEUMS There is such a wide variation in the composition of petroleum from different fields, it would seem possible to make a classification on this basis were it not that no single variety is entirely free from hydrocarbons contained in others. Such a classification has been suggested of the exceptionally pure Pennsylvania petroleum, the sulfur oil from Trenton

Jan 2, 1920

By C. A. Heiland

THERE once was a little kid, whose lot was a very tough one until he grew up. His parents did not have much in common; from all indica-tions, it is probable that the child was not wanted. His father Geology and his mother Physics separated shortly after his birth, which occurred during the World War amid a smoke screen of mathematics. He was kicked around a great deal. His parents could not agree on a name, and they finally christened him "Geophysics," for short. His relatives insisted that the name should be "Geophysical Prospecting," "Geophys-ical Exploration" or "Exploratory Geophysics"; though the youngster has grown up by now, this battle is still going on. His father did not think the child would amount to much until he began to show some unexpected talents, which were acquired, no doubt, from his mother Physics. His progress caused his father no little worry, and he began to wonder whether his offspring would help him in his business when he grew up or would set up shop in competition with the old man. His aunt Petroleum watched his growth with benevolent interest; his uncle Mining remained rather skeptical and cousin Civil Engineering not only assumed the attitude of the man from Missouri but was not much con-vinced even after he had been shown. Making a long story short, the kid decided that he had to stand on his own feet and get along as best he could. Having come from a good family . he possessed some outstanding characteristics such as resourcefulness and a reasonable amount of business ability. He therefore decided that it would be to his advantage to follow in his father's and mother's foot-steps as much as possible, and develop the good qualities of both. As a result, the youngster did fairly well for himself, and his relatives decided that it might be to their advantage to be on better terms with him. Father Geology had come to the conclusion that the boy could be very helpful to him and now wanted him to live in his house. His mother, who had brought him through the teething and measles stages, felt quite capable of bringing up the boy without the help of his father; and, as the fairer sex will do, would confide to a neighbor every now and then that his

Jan 1, 1938

By R. C. Temps, G. E. Aiken

Compania de Acero del Pacifico, S.A., the sole Chilean steel producer, is adding to the expanding Chilean economy with development of the El Algarrobo mine. Expected to go on stream early in 1962, Algarrobo is a conventional open pit mine that will include facilities for ore extraction, crushing and screening, rail transport to the harbor at Huasco, modern ship-loading equipment and maintenance shops. CAP anticipates producing 1.38 mil- lion tons annually of high-grade ore for national and world market consumption. Chilean and North American management and engineering teams combined more than a decade ago in the financing and building of CAP'S Huachipato integrated steel plant. A similar performance is being achieved in northern Chile near the town of Vallenar with the opening of a 50-year supply of iron ore from the Algarrobo deposit. This successful intra-American undertaking deserves special mention in these times when some U.S. foreign assistance programs must be defended, particularly with respect to Latin America. North American financial participation in Algarrobo, through the Export-Import Bank of Washington, represents the greatest portion of the $24 million being invested.

Jan 3, 1962

By Allen D. 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 E. H. Crabtree, T. G. Chapman, V. W. Winters

IN 1939 one of the authors* described advances in carbon-cyanidation for the period 1932 to 1939 • T. G. Chapman: A Cyanide Process Based on the Simultaneous Dissolution and Adsorption of Gold. Trans. AIME (1939) 134, 207. and included: (1) the dissolution of gold in an ore pulp by cyanide and its simultaneous adsorption by carbon, (2) the stage addition of adsorptive carbon and its movement countercurrent to the flow of the ore pulp, and (3) the recycling of adsorptive carbon. Considerable additional experimental and pilot plant work have been done by the authors since 1939 and the results of such work E. H. CRABTREE, JR., Member AIME, is Director of Milling, Eagle-Picher Mining and Smelting Co., Miami, Okla., V. W. WINTERS is Superintendent, Sahuarita Concentrator, Eagle-Picher Mining and Smelting Co., Tucson, Ariz., and T. G. CHAPMAN, Member AIME, is Dean, College of Mines, University of Arizona, Tucson. AIME Sun Francisco Meeting, February 1949. TP 2744 B. Discussion (2 copies) may be sent to Transactions AIME before March 31, 1950. Manuscript received March 3, 1949. have been sufficiently encouraging to justify a second paper. Developments from 1939 to 1948: In 1941, Verne W. Winters did the first experimental work in eliminating agitation during dissolution and adsorption and thereby demonstrated that the dissolution of gold by cyanide and its simultaneous adsorption by carbon take place essentially to completion in a stagnant pulp. Shortly thereafter, and as a result of the stagnant pulp experimental work, Winters and Chapman demonstrated that soluble gold, in a cyanide ore pulp, would migrate from the ore pulp through a perforated container and be adsorbed by carbon within the container. During the same year, the Eagle-Picher Mining and Smelting Co. erected a 25-ton capacity pilot plant at the Harquahala mine about 9 miles from Salome, Ariz. Experimental work at this plant comprised chiefly the stagnant pulp modification of carbon-cyanidation although considerable work was done in the grinding and activation of carbon, and testing various methods of extracting adsorbed gold from carbon. Soon after the completion of the Harquahala

Jan 1, 1951

By V. H. Wilhelm

During the first half of the year 1935, the oil industry in California was on a fairly profitable basis, owing mainly to the operation of the Petroleum Marketing Agency. Coincident with the discontinuance of enforced curtailment, California production surged upward from an average of about 500,000 bbl. per day (over the first five-month period) to approximately 625,000 bbl. per day (over the last seven-month period). On Dec. 9 the state production had reached a peak of over 700,000 bbl., a figure that had not been approximated since the early days of voluntary curtailment (Fig. 1). A price cut was instituted during the last half of August, but had no deterring effect on operators that were determined to take advantage of the breakdown of curtailment and produce to capacity. New reserve figures, compiled from actual potentials, available after cessation of curtailment, revealed the startling fact that California reserves were rapidly declining. This situation, coupled with the desire among operators to obtain a more equitable price for their dwindling reserves, caused a restoration in November of a portion of the August price slash. A further rise in price was effected in early December, and crude quotations at the end of the year closely approximated those in effect during the first right months. At the close of the year, the industry felt confident that the production situation was under control. In all fields where competition is keen because of close spacing, production is gradually declining. In the Los Angeles Basin especially there is no likelihood of a large amount of overproduction, unless a new pool is discovered or deeper drilling reveals a prolific source of crude. As long as the fields that are operated by a few companies, such as Kettleman Hills, North Belridge, Ventura Avenue, West Coyote, Dominguez, and some others, can be controlled, it is believed that the overproduction problem in California will be solved.

Jan 1, 1936

The following is an incomplete list of members and guests who called at Institute headquarters during the period Dec. 10, 1918 to Jan. 10, 1919. P. G. Bandy, Mexico City. Wm. B. McKinley, Yonkers, N. Y. Bennett R. Bates, Berkeley, Cal. Captain C. E. McQuigg, Conn. William T. Bates, Mascot, Tenn. Lt. H. G. Mathews, Cal. Lt. Don C. Billick, Alturas, Cal. Lt. M. S. Mazany, Mich. L. E. Booth, Watertown, Mass. Ralph A. Meyer, Hill City, S. D. J. T. Boyd, Denver, Colo. C. F. Moore, Boston, Mass. J. R. Buchanan, Pasadena, Cal. H. W. Nichols, Chicago, Ill. Ensign G. M. Burke. R. B. Olsen, Mays Landing, N. J. Captain E. H. Clausen. M. L. O'Neale, Gouverneur, N. Y. F. L. Cole, Manila; P. I. F. W. Osborn, New York, N. Y. Joules Cousin. Lt. Fred S. Porter, Alaska. A. Faison Dixon, Washington, D. C. G. M. Richards, Palmerton, Pa. James T. Dixon, London, England. T. C. Roberts, E. Orange, N. J. Everett Drennen, Elkins, W. Va. W. E. Ruder, Schenectady, N. Y. F. Eichelberger, Helena, Mont. Ensign W. A. RuKeyser, Boston. R. B. Eldredge, Colorado Springs, Colo. A. H. Sawyer, Boston, Mass W. F. Ferrier, Ottawa. Lt. D. F. Schindler, New York. Martin Fishback, Benson, Ariz. L. G. Sparks, Greenshurg, Kan. T. E. Fisher, Dover, N. J. W. H. Staver, New York N. Y. D. C. Gilbert, Ft. Wayne, Ind. Douglas B. Sterrett, St. Cyr, Canada. Lt. Lauriston B. Herr, Cuba. Warren D. Thompson. G. S. Holmquist, Washington, D. C. Enrique Touceda, Albany, N. Y. Lt. E. Ross Housholder, Ohio. Mathew van Siclen. Hugh C. Ingle, Santa Rosa, Cal. Flying Cadet Christian Vrang, Cal. Lt. M. W. Kishman, Ariz. L. G. Weeks, Bisbee, Ariz. Hugo E. Koch, Watertown, Mass. C. E. Wheelock, Mogollon, N. M. H. M. LaFollette, LaFollette, Tenn. Major A. E. White, Washington, D. C. Clinton R. Lewis, Dawson, Y. T. Lt. J. L. White, Humboldt, Ariz. The Secretary of the Institute has received with sincere appreciation a Christmas card extending the season's greetings from the officers' mess of the 3d Tunnelling Company, Canadian Engineers, B. E. F., France, and takes this means of reciprocating to these officers and men of the company the best wishes of the members of the Board of Directors. Charles E. Addams has removed from Ray, Ariz., to Phoenix, Ariz., where he is chairman and director of the Arizona State Council of Defense.

Jan 2, 1919

By F. E. Bash

PREVIOUS to the war, this country depended on Europe for its supply of a number of alloys of great importance in the manufacture of electrical apparatus and equipment. When this source was cut off shortly after the beginning of hostilities and the small stocks in the United States were exhausted, either inferior substitutes had to be used or the manufacture of the apparatus suspended. Since electrical equipment was of primary importance in the prosecution of the war, the substitutes had to be used until the composition and processes of manufacture of the alloys could be determined. Included among these alloys was one generally known as manganin, which is composed chiefly of copper and manganese and which, beside having a low-temperature coefficient of resistance, has a low thermal electromotive force against copper. These qualities make it valuable for the manufacture of electrical instruments and machines in which it is used in the shape of wire, rod, and strip. As a result of these circumstances, an investigation was started to deter mine how manganin could be made on a commercial basis so that a product of uniform quality and the necessary electrical characteristics could be produced. The object was to procure an alloy with temperature coefficient of resistance not greater than T 1 X 10-5 per ° C. and a thermal e.m.f. against copper no greater than that of the imported material. It is characteristic of manganin that the temperature-resistance curve is not a straight line but has a peak, which varies in position with different samples; it is most desirable, however, to have it at a temperature of 25° C. if possible. The coefficients of manganin from all records available ranged from a large negative to a large positive value. The composition as reported by different authorities is given in Table 1. Prof. Matthew A. Hunter, of Rensselaer Polytechnic Institute, made up a number of small melts of manganin in a graphite crucible and the one that he reported as having the best coefficient gave the following analysis: Copper, 83.6 per cent.; nickel 2.5 per cent.; manganese,-13.6 per cent.; iron, 0.3 per cent. An analysis of a sample of German manganin gave the following: Copper, 82.6 per cent.; nickel, 3.8 per cent.; manganese, 12.8 per cent.; iron 0.7 per cent.

Jan 9, 1919

By N. Brown, M. Herman

ORDERING'S effect on the creep strength and other plastic properties of metals is unknown at the present time. Sachs and Weerts' attempted to compare the mechanical properties of the ordered and disordered state by comparing a quenched specimen with one annealed for a long time at a low temperature. This experiment is unsatisfactory because it introduces a possible effect from quenching. Barrett' used a hot impact test, but his method was not sufficiently sensitive to indicate any discontinuity in plastic behavior in the neighborhood of the critical temperature. On the theoretical side, Fisher9 as suggested that short range order would strengthen an alloy, but he gives no conclusions as to the effect of long range order. Cottrell" has discussed the interaction between long range order and dislocations, but does not indicate whether slip in a completely ordered alloy without domain boundaries is appreciably more difficult than slip in the disordered state. Because order exists in so many alloy systems, it is most important to prove experimentally whether long range order weakens or strengthens a metal. This investigation used -brass because: 1) it orders

Jan 1, 1957

By Ira B. Joralemon

The sampling of disseminated copper deposits has been describeu often but the method of combining assays to give the true shape and value of the orebody as it will be mined has received less attention. As the ore mined during five or ten years at several of the great disseminated properties has averaged materially lower in grade than the published estimates, the question of the sampling and estimating of these orebodies seems timely. In this paper, attention is given particularly to factors that may cause errors in the final estimate. Sampling of diamond-drill holes, churn-drill holes, and underground workings is briefly described in the first part of the paper; then the method of combining assays to give the average grade and tonnage that will be mined is taken up in some detail. The necessity of study of the geology of the deposit and of probable costs is emphasized. Finally, the methods of calculating tonnages are outlined. DlAMOND-DRILL SAMPLING There are three main requisites for accurate diamond-drill sampling. First, the core should be removed and the hole cleaned out at the beginning of every sampling interval, usually 5 ft. (1.5 m.). After the rods are let down, water should be run through them until it becomes clear. The water must be clear before drilling starts. 'In this way the material knocked down from the sides of the hole by the descending rods is washed away, instead of being left to salt the sludge sample. The second requisite is to save all the sludge and all the core from every sampling interval. Where the material is uniformly heavy, the cuttings will settle suffciently in a box, through which the sludge flows s1owly.l Where part of the material is too light to settle readily, the sludge should be run into barrels, and allowed to settle until the water becomes clear. Then the clear water is siphoned off, and the sludge evaporated to dryness over a slow fire, sacked, and assayed.2 To obtain

Jan 1, 1925

Prof. G. W. MAYNARD, New York City (communication to the Secretary): Prof. Christy, in his admirable paper on "The Growth of American Mining Schools," has overlooked the work done by the Rensselaer Polytechnic Institute in its department of mining and metallurgy. This oversight is naturally due to the fact that the department was, for lack of money, discontinued in 1871. It was organized by the writer in 1867, starting with ten students, who had already completed the first two years of the civil engineering course in the Institute. The course covered two years, specifically devoted to mining, metallurgy and assaying, which, in connection with the two years' drill in the civil engineering department made a four years' course. During the four years of the existence of the department, thirty-five students took the course, of whom twentyfive graduated; and of this number eight have been members of the Institute of Mining Engineers, and the majority of them have occupied high positions in the profession. The equipment of the department was, at that time, second only to that of the Columbia School of Mines. As Prof. Christy has cited other institutions which are not distinctively mining schools, but in which the ruining course was subordinate to other courses, it seems to me that the work in this line carried out by the oldest engineering school in the country may very properly be referred to. In addition to the regular mining course, a special course in assaying was given; and many young men were here prepared for positions in the mines and metallurgical works of the west. PROF. George F. Swain, Boston, Mass.: I have listened with great interest to Prof. Christy's valuable paper, but there is one conclusion at which he arrives that appears to me entirely unjustifiable, and to which I desire to take exception. Prof. Christy finds that of the total wage-earners in the United States in 1880,10.41 per cent. were employed in " trade and transport;" 20.24 per cent. in " manufactures and mechanics," and 1.83

Jan 1, 1894

By A. R. Denison

To those who are unfamiliar with the nomenclature in common use among operators in the Mid-Continent, the Permian Basin is a term to cover several widely separated productive areas. It includes what is designated in trade journals as the Panhandle fields, the West Texas fields and Southeastern New Mexico fields. It is bounded roughly on the east by the 100th parallel, on the west by the 104th parallel, 011 thr south by the Rio Grande River and various mountain ranges and on the north by the north line of the Texas Panhandle. The name is derived from the location of these three widely scattered areas which are all in a broad geosyncline which is chiefly filled with sediments of Perrliian age. The oil fields as now known and the approximate limits of the Permian Basin are shown in Fig. 1. The major part of the production in these areas comes from liniestonc or dolomite of Permian age. Some granite wash and sandstone production has been developed but ordinarily does not yield as large initial production as the limestone or dolorliite. Introduction During 1926, Texas, exclusive of the Gulf Coast, produced 12G1SS-1,-952 bbl. of oil,' of which 40,727,877 bbl., or 32 per cent., was produccd in the West Texas Permian Basin. During 1927 the same area in Texas produced 167,176,000 bbl. %f oil, of which 89,779,000 bbL13 or 52 per cent., was produced in the West Texas Permian Basin. The increase in the total production of Texas is about equivalent to the increase in production in the Permian Basin. Since production in the Panliandle District declined during the entire year, the increase of production in the West Texas Permian Basin, and also the increase in Texas, is due to the enormous increase from the West Texas fields. Daily average pl-oduction in the West Texas fields increased from 68,211 bbl. on ,Jan. 8 to

Jan 1, 1928

By Lewis A. Riley

I desire to submit, for the consideration and information of the members of the Institute, the following data, drawings, and tables, showing what I believe will be interesting information with regard to the diamond drill, and its uses in developing mineral lands. I would first say that the results given have been obtained during the past two years by means of two drilling machines belonging to the Lehigh Valley Coal Company, operating on their coal lands in the Mahanoy, Lehigh, and Wyoming regions. 1st. A tabulated statement, giving location of borings, date, progress, total cost, itemized cost per foot, etc. 2d. Section showing strata bored in Nos. 5 and 10 holes at Mt. Carmel, see Plate VI. 3d. Section showing strata bored in No. 19 hole at Hazleton, see Plate VI. 4th. Photograph and description of drill No. 2. From the first it will be seen that the total number of test-holes bored up to May 1st of this year is 24; 9 of these are in the Mahanoy region, 6 in the Lehigh region, and 10 in the Wyoming region, in all of which cores have been taken for the whole distance. The total distance bored is 9902 feet. The majority of the holes have been put down for the purpose of proving the lower veins of the coal series, and have had to encounter the harder rocks of the coal formation. Much of the distance has been through the lower conglomerates, going in some cases through the coarse egg conglomerate, the foundation of the coal deposit, and to the green sandstone and red shale which underlie it. These lower sandrocks and conglomerates are among the hardest known to geologists, and present a formidable resistance to the exploring drill. This fact must be taken into consideratiotl in comparisons of cost of drilling, and when considered will still further improve the very favorable results I am able to show in my statement of costs. In illustration, I will cite the work of one bit when boring in the upper or softer rocks of the Wyoming region, where 280 feet were obtained without resetting, while in the Lehigh and Mahanoy regions, in the lower and harder rocks, bits set with the same quality of diamonds would only bore from 3 to 20 feet before being worn out. In this connection it may

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.

Jan 1, 1939

Jan 1, 1906

By R. P. Ehrlich, D. A. Dahlstrom

In the hydrometallurgical circuit, many phase separation steps are usually necessary. Typical steps are pregnant liquor - leach residue separation by counter- current decantation or continuous vacuum filtration, clarification of liquids prior to precipitation, ion exchange or solvent extraction, dewatering of final product, etc. The paper discusses the more recent advances in these areas and considers general operating parameters and cost factors. In addition, emphasis is placed on future needs because of the growing importance and necessity of hydrometallurgical processing of minerals.

Jan 1, 1973

By E. S. Machlin

The alternate processes by which solute atoms can limit the migration of grain boundaries have been considered. At the lowest solute concentrations the controlling process is "mechanical breakaway" in which the solute atoms affect the driving force and not the mobility. In the next higher range of solute concentration, solute atoms are bound to the boundary and diffuse by boundary diffusion along cusps in the boundary developed at the solute atoms. In this region the boundary velocity is controlled by the component in the direction of boundary migration of the rate at which the bound solute atoms can diffuse along the boundary. At still higher concentrations, it is predicted that boundaries break away from the binding solute atoms by thermal activation. The specific behavior Predicted is consistent with the observations of Aust and Rutter. The most striking agreement between prediction and experiment is that obtained for a range of solute concentration in which the boundary velocity is inversely proportional to the cube power of the solute concentration. MaNY models have been devised for the atomic steps in the motion of a grain boundary. McLean1 has listed some of these models and Aust and utter' have evaluated these and other models. If there are

Jan 1, 1962

By R. W. Raymond

In a former paper (Trans., xvi., 770) I gave the text of the archaic mining law of the State of New York, together with some comments upon its curious provisions. In that connection I pointed out two facts : first, that the law seemed to have originated in the schemes of private parties, who were satisfied with those parts of it which concerned them particularly; and secondly, that the remaining provisions had been hitherto quite inoperative, for the reason that mines of the character to which they referred had not been discovered in the State. Since 1888, when that paper was written, the New York Legislature has passed several acts relating to mines as follows: 1. Chapter 394, Laws of 1890. This provides for an inspection

Jan 1, 1895