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By Tracy Jarrett

THE alloying of various elements with gold to produce different colors is an old art, but the effect of each element or combination of elements is not generally known. Investigations have been made in this field by F. E. Carter,1 E. M. Wise,2 and L. Sterner-Rainer.3 It is the intent of this paper to present in schematic diagrams the effects of various ele¬ments upon the color and the melting point of gold alloys. In this investigation 2-oz. melts made in a high-frequency induction furnace were used for all tests. The melting points were determined by the use of a calibrated chromel-alumel thermocouple sealed in a thin-walled alundum tube. The couple was then submerged in the molten metal and the freezing and melting points were determined by using a Leeds and Northrup potentiometer. By checking several melts using copper, zinc and gold, it was found that the accuracy of determining the melting point was within ± 5° F. To determine the differences in colors and to classify them, a wet tissue paper was placed over the polished samples and examined under a uniform white light. The 2 by ½ by 0.045-in. samples were cut from 50 per cent cold-worked strip. The original ingot was 3 by ¼ by ¾ in. This visual comparison, although not scientifically exact, served as a quite satisfactory means for determining and classifying these differences. The base alloys, or "hardeners," were first made up and analyzed, after which the gold and silver were added. This method of making up the alloys was chosen so that the same base alloy could be used for the gold alloys of different karats. The first series consisted of gold, copper, zinc and nickel, the copper comprising from 85 to 65 per cent of the content of the "hardener" and the zinc and nickel replacing copper. The second series consisted of gold, silver, copper, zinc and nickel, the copper comprising from 85 to 65 per cent of the content of the hardener with the silver, nickel and zinc replacing copper. There was no particular reason for choosing these combinations, except that they gave a color range from red-pink to white.

Jan 1, 1939

By Ralph Arnold

While much geological work and drilling have been done in Venezuela, the incompleteness of geological evidence obtainable and the restricted areas in which drilling has been done make any estimates of oil resources extremely speculative. Nevertheless, it is felt that the data given are justified, in the belief that the ideas of a geologist familiar with the region are better than those of a promoter. The oldest beds of interest to oil men are those of the Cretaceous, which are well developed in eastern Venezuela and about parts of Lake Mara-caibo. In both cases, a hard massive limestone is overlain by a great thickness, most of which is shale. In the west, in places this shale is more than 2000 ft. (610 m.) thick, while in the east it-mag attain 3500 ft. (1067 m.). The limestone and parts of the shale are oil producing. In the east, the Tertiary where present is almost entirely covered by the Quarternary, but in the west it is well developed. In probable unconformity over the Cretaceous shales is found a series of sandstones and shales, which may be called the lower coal series. It is well developed southwest of the lake, where it is the oil container, and is probably the lowest series exposed east of the lake. Above this is the Pauji shale, which is probably the point of origin of all the oil east of Lake Maracaibo and in the State of Falcon. It has a thickness of about 3000 ft. (914 m.) in the Mene Grande region. The upper coal series is developed as a great thickness of sands, shales, and clays, with some partly consolidated limestone. Its thickness may be as great as 10,000 ft. It is the oil container of the Falcon-El Mene region and a probable location for oil in some of the area about the lake. It may or may not include the so-called Maracaibo series in which the oil is found at Mene Grande. Over much of Venezuela, the Quarternary is present in unknown thickness, which probably is not great. It obscures oil structure in all cases and presents the greatest hazard of oil exploration for the fields which probably exist below.

Jan 1, 1923

By F. C. Clapp

Although many oil fields have been, and still are being, discovered in Oklahoma, the geology and structure of most of them have not become familiar to the general public because of the delay in securing government geological surveys and the reluctance of oil companies and other intercsted parties to give out their "inside information " Therefore, until official surveys are available, it behooves us to publish geological results as soon as possible. Fortunately the writer has been authorized by the Cement Field Oil Co. to publish his data on the Cement field, Caddo County, at this time. Locality and Description The Cement field is situated in the part of Oklahoma known generally until recently, as "Healdton fields," and lies 60 mi. (96 km.) northwest of the Healdton field proper. Like the Healdton field, it forms an approximate ellipse, trending northwest and southeast through the village of Cement on the St. LouisSan Francisco Railroad, on which it is reached in 21/2 hours from Oklahoma City. In its geological structure, the field constitutes an anticline over 13 mi. (21 km.) long and from 1 to 3 mi. wide; the point of greatest width being not far from its intersection by the above-named railroad. The major axis trends north 75' west from the village of Cement; but eastward appears deflected (if field interpretations are correct) to about south 45" east. About 5 mi. south lies an approximately parall el syncline, which may be conveniently called the Cyril syncline, the south and west boundaries of which may be distant many miles, but forming a closed basin south of the Cement anticfine. The positjon of the offsetting synclinal axis, which is believed to lie north and east of-Cement, has not been discovered. TOPOGKAFHY In the southwest part of the state, nearly all maps of Oklahoma show two mountain areas—Arbuckle and Wichita—which are conspicuous geological and topographic landmarks. In addition, some maps show a third, and smaller, range, named the Keechi Hills, in the vicinity of Cement. These hills also form a conspicuous feature in the landscape; but for some reason they have been neglected by geologists, and the

Jan 1, 1921

By V. F. Hollister, M. Bernstein

The Copaquire porphyry copper deposit lies in an island of pre-Upper Tertiary rocks surrounded by Quaternary and Upper Tertiary formations. The pre-Upper Tertiary appears to be a horst block in a typical basin-range setting. Major right lateral faults have been mapped within the range from Chuquicamata north to Copaquire. All of the major porphyry copper deposits known in the block (e.g., Quebrada Blanca, El Abra, Chuquicamata, and Copaquire) are on or are very close to one of these major right lateral shears. In the Copaquire district, an epizonal igneous complex with diorite, quartz diorite, quartz monzonite, and intrusive dacite (in that intrusive order) invade folded Jurassic shale. Mineralization appears spatially and temporally associated with the quartz monzonite porphyry and dacite. Alteration zoning shows two separate core phyllic (quartz-sericite-pyrite) zones within one large argillic (clay-pyrite) zone. A propylitic (chlorite) zone is peripheral to the argillic zone. No potassic zone has been recognized yet at the surface. The intrusive petrology together with the phyllic, argilic, and propylitic alteration zoning as well as the chalcopyrite-molybdenite ore mineralogy characterize this deposit as being typical of the Lowell and Guilbert model. Copper and molybdenum minerals appear to be most strongly developed in the phyllic zone, in either a breccia or a zone of veinlets and stockwork which trend dominantly northeast, conjugate to the district's largest fault, the Sulfato fault. The setting is basically similar to that found in some other porphyry copper deposits in this block, in that the ore body is a zone of veinlets which appear to be genetically related to movement on a major north-south trending right lateral fault. The presence of the major fault in each deposit, and the speculative hypothesis that paleo-subduction zone operated at the time of mineralization, suggest the possibility that mineralization took place when a major fault permitted escape to the surface of cal-calkalic magma generated in a subduction zone as proposed by Ericksen. A hypothesis such as that proposed by Ericksen explains the near linearity of porphyry copper deposits in Chile, since the source of calc-alkalic magma would exist at about the same distance from a paleo-trench throughout the length of the paleo-subduction zone.

Jan 1, 1976

By Paul Billingsley

The Asientos-Tepezala district is in the north of the State of Aguasca-lientes, about 30 miles north of the city of Aguascalientes, the capital. The district is reached by a standard-gage railway on the west side through the junction, Rincon de Romos, which is on the main line of the National Railways of Mexico from El Paso to Aguscalientes. The terminal is Tepezala. On the east side a narrow gage connects Asientos with the junction, San Gil, on the main line, Asientos to San Luis Potosi. Tepezala on the west side of the Asientos hills is about 2 miles from Asientos on the east side. The area between the two mining centers is separated by a low subdued divide which forms the central part of the hills. The district is in a group of isolated hills surrounded by characteristic bolsón plains. The hills rise above the surrounding plains about 6500 to 10,000 ft.; the highest peak is Alta Mira. The two mining districts lie somewhat upon the flanks of the hills at about the same elevation, 7200 ft. The district is an old one and has been known since early in the 17th Century when the mines were worked by the Franciscan Monks. Their mining operations, which were limited to the oxidized ore above the water level, consisted chiefly in extracting silver from the Santa Francisca vein. To judge from the old workings and the remains of surface plant, the operations were on a large scale. By modern mining operations since about 1900, the various mines of the district have been one of the principal sourees of ore for the smelter located at Aguascalientes. Topography The topographic features of the Asientos hills are largely controlled by the character of the underlying rocks. During the Tertiary period, the entire group of hills was probably covered by extrusive volcanic material in the form of cones and lava flows. The central part of these have since been carried away by erosion, so that remnants have been left along the borders of the hills. These remnants form rather conspicuous peaks,

Jan 1, 1927

By James Terry Duce

The gross production on the Island of Sahreirl during 1944 was approximately 6,700,000 U. S. bbl. No additional wells were drilled in the field during the year, but a number that were plugged off during the critical days of the war were brought back on production. This work is continuing. The construction of the extension of the refining plant was continued during the year and the new crude still was started in November. In Arabia, the production for the year 1940 was 5,074,838 U. S. bbl. Four wells were completed in Dammam field and all were commercial producers. Production for 1941 was 4,310,110 U. S. bbl. Seven more commercial producing wells were completed in Dammam field, and Well No. I at Abqaiq was complcted at 6180 ft. and was also a commercial producer. In 1942 production was 4,530,492 U. S. bbl. Abqaiq No. 2 was drilled to 5785 ft. but was left standing because of mechanical difficulty. The 1943 production was 4,868,- 184 with one well drilled, Abqaiq No. 3 completed at 6488 ft. and a commercial producer. Total production in Arabia for the year 1944 was around 7,800,000 U. S. bbl. and at the close of the year was running at approximately 40,000 bbl. per day. The small refinery, built in 1939, at Ras Tanura was in operation in the fall and a new refinery is being constructed. Only three wells were completed during the year—the El Jauf well in Northern Arabia (completed at 10,974 ft.) which did not bring in commercial production and Wells No. 4 (completed at 6270 ft.) and No. 5 at Abqaiq (completed at 6751 ft.), which were brought in as substantial commercial producers. Production for the year was entirely from the Dammam field. In this field, some of the wells that had been plugged off early in the war were brought back in production and this work is continuing. At the close of the year, one well was drilling in the Abqaiq field and an additional well was drilling at Qatif, the latter being a wildcat. Neither of the wells in question had reached producing horizons on the first of January.

Jan 1, 1945

By O. C. Wheeler

The total oil production from Colombia during 1939 amounted to 23,774,151 bbl., constituting a new high record. Of this amount the Tropical Oil Co. produced 22,374,151 bbl. from its De Mares concession and the Colombian Petroleum Co. produced 1,400,000 bbl. from its Barco concession beyond the eastern Andes. The Socony Vacuum Oil Co. produced a small amount of crude from its Las Monas wells north of the Sogamoso River in the Magdalena Valley for consumption on its own property, but this is not included in the figures given above. The South American Gulf Oil Co. provided the outstanding development in the country by the completion, late in the year, of its 12-in. pipe line from the Colombian Petroleum Company's Barco concession to the coast at Covenas. This was a notable accomplishment, achieved in the face of tremendous natural obstacles. With the completion of this line there are now two crude-oil outlets from the interior of Colombia to the coast, the other being the Andian National Corporation's line down the Magdalena Valley from Barranca Bermeja. The Barco property becomes the second major producing area in Colombia. The acquisition of prospectivc oil lands continued at about the same level as during the prcvious year. Most of the lands taken up or applied for had their subsurface rights vested in the National Government. Relatively little interest was taken in the leasing of privately owned lands. Tropical surrendered its Putana concession on the Sogamoso River after finding it to he nonproductive. The status of applications for National lands that had been accepbed or on which concession contracts had been awarded at the end of the year is shown in Table 3. In the Magdalena Valley wildcat drilling in the search of new fields was conducted to the east of Puerto Berrio by the Compania de Petroleo Shell de Colombia, Compania Coloinbiaila de Petroleos El Condor and by the Sociedad Nacional del Carare; further down the valley to the cast of Puerto Wilches, the Socony T'acuum was drilling two wildcats. No discoveries resulted from this exploratory work. On the Barco conces-

Jan 1, 1940

By O. C. Wheeler

The total oil production from Colombia during 1939 amounted to 23,774,151 bbl., constituting a new high record. Of this amount the Tropical Oil Co. produced 22,374,151 bbl. from its De Mares concession and the Colombian Petroleum Co. produced 1,400,000 bbl. from its Barco concession beyond the eastern Andes. The Socony Vacuum Oil Co. produced a small amount of crude from its Las Monas wells north of the Sogamoso River in the Magdalena Valley for consumption on its own property, but this is not included in the figures given above. The South American Gulf Oil Co. provided the outstanding development in the country by the completion, late in the year, of its 12-in. pipe line from the Colombian Petroleum Company's Barco concession to the coast at Covenas. This was a notable accomplishment, achieved in the face of tremendous natural obstacles. With the completion of this line there are now two crude-oil outlets from the interior of Colombia to the coast, the other being the Andian National Corporation's line down the Magdalena Valley from Barranca Bermeja. The Barco property becomes the second major producing area in Colombia. The acquisition of prospectivc oil lands continued at about the same level as during the prcvious year. Most of the lands taken up or applied for had their subsurface rights vested in the National Government. Relatively little interest was taken in the leasing of privately owned lands. Tropical surrendered its Putana concession on the Sogamoso River after finding it to he nonproductive. The status of applications for National lands that had been accepbed or on which concession contracts had been awarded at the end of the year is shown in Table 3. In the Magdalena Valley wildcat drilling in the search of new fields was conducted to the east of Puerto Berrio by the Compania de Petroleo Shell de Colombia, Compania Coloinbiaila de Petroleos El Condor and by the Sociedad Nacional del Carare; further down the valley to the cast of Puerto Wilches, the Socony T'acuum was drilling two wildcats. No discoveries resulted from this exploratory work. On the Barco conces-

Jan 1, 1940

By A. Hamilton Garner

Northern Venezuela has been divided into three provinces, as follows: The Llanos, the Andean, and the Maracaibo Basin and Falcon. The first and third are large sedimentary basins offering, possibilities for oil accumulations. Oil is known to occur in many formations ranging in age from Cretaceous to Quaternary. The most prolific source of oil is probably the Cretaceous shales and limestones, from which the oil appears to have migrated into overlying porous beds. Faulting or fracturing, folding, and porosity are governing factors in the localization of commercial deposits. THE occurrence of oil seepages in Venezuela has been known since the early days of Spanish occupation. It was not until 1912, however, that any serious exploration work was undertaken. In that year, the Caribbean Petroleum Co., then a subsidiary of the General Asphalt Co., employed a large staff of geologists to make a systematic survey, of large areas in eastern and western Venezuela, selecting the most, desirable localities out of the immense area covered by the Valladares concession. This preliminary work was completed in the fall of 1913, and in February, 1914, the company completed its first commercial well at Mene Grande. Development work has progressed slowly, for various reasons, but petroleum in quantity has been encountered in nine widely separated localities. The Mene Grande field has been put on a producing basis and approximately 4,000,000 bbl. of oil are being shipped annually. Increasing quantities of oil are now being drawn from El Mene and La Rosa. In the light of these developments, the world's need for oil reserves, and the proximity of Venezuela to the United States, American capital is being attracted more and more to Venezuela. Although considerable careful geological work has been done in Venezuela by the various oil companies now operating, most of the data is. buried in the company,, files, and the published literature has been extremely meager. The most valuable contribution to date has been a map and report by Jahn, which, as it was printed in Spanish, is not. generally available to the American oil public.

Jan 10, 1924

By Ralph Arnold

WHILE much geological work and drilling have been done in Venezuela, the incompleteness of geological evidence obtainable and the restricted areas in which drilling has been done make any estimates of oil resources extremely speculative. Nevertheless, it is felt that the data given are justified, in the belief that the ideas of a geologist familiar with the region are better than those of a promoter. The oldest beds of interest to oil men are those of the Cretaceous, which are well developed in eastern Venezuela and about parts of Lake Maracaibo. In both cases, a hard massive limestone is overlain by a great thickness, most of which is shale. In the west, in places this shale is more than 2000 ft. (610 m.) thick, while in the east it may attain 3500 ft., (1067 m.). The limestone and parts of the shale are oil producing. In the east, the Tertiary where present is almost entirely covered by the Quarternary, but in the west it is well developed. In probable unconformity over the Cretaceous shales is found a series of sandstones and shales, which may beg called the lower coal series. It is well developed southwest of the lake, where it is the oil container, and is probably the lowest series exposed east of the lake. Above this is the Pauji shale, which is probably the point of origin of all the oil east of Lake Maracaibo and in the State of Falcon. It has a thickness of about 3000 ft. (914 m.) in the Mene Grande region. The upper coal series is developed as a great thickness of sands, shales, and clays, with some partly consolidated limestone. Its thickness may be as great as 10,000 ft. It is the oil container of the Falcon-El Mene region and a probable location for oil in some of the area about the lake. It may or may not include the so-called Maracaibo series in which the oil is found at Mene Grande. Over much of Venenzuela, the Quarternary is present in unknown thickness, which probably is not great. It obscures oil structure in all cases and presents the greatest hazard of oil exploration for the fields which probably exist below.

Jan 7, 1922

By Oliver B. Knight

The producing formation in the South Field, or "Golden Lane" structure of Mexico, is a buried ridge of reef limestone of Comanchean age overlain unconformably with sediments of Upper Cretaceous, Eocene and Oligocene. The structure extends in a long sweeping arc, with the convex side toward the west, from San Geronimo, Vera Cruz, to San Isidro, south of the Tuxpam River, which it crosses at the town of Alamo. It is 52 miles long and averages 3/4 mile in width. The surface of the producing formation of El Abra limestone consists of a series of minor parallel highs which are separated longitudinally by synclinal troughs and laterally by structural saddles. The presence of these highs has been of utmost importance in the development of the field, especially in recent years when the salt-water level has risen above the synclines and confined the oil to the isolated highs. In many cases, faulty information and interpretation of the subsurface has resulted in drilling costly dry holes and salt-water wells. Development The development of the Golden Lane was started by the Mexican Eagle Oil Co. in 1906. San Diego No. 3, usually known as Dos Bocas, the first producing well on the structure, was completed on July 4, 1908. This well came in unexpectedly for an estimated daily production of 129,000 bbl., and, as the casing was not properly set, the well flowed wild into the Tamiahua Lagoon, causing a loss of several million barrels of oil. In flowing wild the well formed a crater which covers an area of 48 acres, out of which salt water and small quantities of gas still flow. Casiano No. 2, the Huasteca Petroleum Co., which yielded 200 bbl. of oil daily, and which was completed in November, 1909, was the next producing well to be drilled on the structure. In 1910, the same company completed Casiano No. 7, with an initial production of 50,000 bbl. daily, and Casiano No. 1, which produced 200 bbl. daily. In the same year, the Mexican Eagle Oil Co. completed its Potrero del Llano wells 1, 2 and 4, with initial productions of 500, 400 and 100,000 bbl. respectively. From 3910 to the latter part of 1919, development proceeded

Jan 1, 1931

By Thomas T., Read

DESIRABLE as it is to summarize what has been set forth in preceding chapters, the task can only be approached with great hesitation. What follows represents the personal views of the author at the moment of writing, reserving the privilege to change them on more mature reflection or in the light of further evidence. With that reservation they may be stated somewhat as follows. Education for the mineral industries falls into two categories; general education and technical vocational, using the word vocational not in its usual sense but to signify preparation for specific activities, in which sense a law school is a vocational school. Even at the beginning, as indicated in the first chapter, mineral industry education was partly general and, partly technical and that relationship still persists, because technical education requires a firm basis of general education. Our general American system is to provide free public' general education through the twelfth grade, or completion of high-school work, though there are already many technical vocational high schools, and even in a community where nearly all the young people are preparing for entrance to college there will be some who wish to qualify for employment at the end of the high-school course, or even on completing junior high. Our educational system, therefore, has not only to provide education for those who intend to proceed beyond the twelfth grade but also for those who, for a variety of reasons, may wish or be forced to cease full-time education at any level between the first and twelfth grades. This study has been chiefly concerned with the problem of what kind and how much technical education to provide for those who have completed the twelfth grade and who wish to make their living in the mineral industries. The obvious fact that the mineral industries employ all sorts of trained persons,

Jan 1, 1941

By D. M. Dunbar, H. C. SCHLILTZ

HE Chile Exploration Co.'s mine and reduction plant are at Chuquicamata, Chile, on the eastern edge of the Atacama Desert, 163 miles northeast of Antofagasta, 80 miles from the Pacific Ocean, and 70 miles from the Bolivian border and at an altitude of 10,000 ft. Guggenheim Brothers started prospecting in -4pri1, 1912, and purchased the main property, in October of that year; the property is now controlled by the Anaconda Copper Mining Co., which acquired it in January, 1923. The orebody strikes north 10" east, and has a dip of about 64" west. The length, as far as developed, is approximately 1% miles; the width averages sightless than mile.

Jan 1, 1925

By HUNTINGTON ADANS

(Wilkes-Barre Meeting, June, 1911.) THE arrangement of a flow of cyanide-pulp through Pachuca tanks in agitation, so as to permit a continuous process, instead of alternate filling, agitation, and emptying, has been proposed by various writers within the last two years, and more particularly by A. T. Grothe, agent for the Brown patents on Pachuca tanks in Mexico. It was first put into practice, I believe, by M. H. Kuryla at the Esperanza mine in El Oro, Mexico. The starting of agitation in Pachuca tanks after filling may offer no serious difficulties with ores which do not settle rapidly in such tall tanks; and the adaptation of the tanks to continuous agitation under such conditions may give simply a somewhat more convenient method of treatment and greater agitation-capacity for a given number of tanks, because of the saving -of time lost in filling and discharging. But in the treatment .of pulp which tends to settle rapidly, as in the cyaniding of concentrates or of the whole pulp of ores containing heavy sulphides, the packing of the slime at the bottom may, cause much trouble. The use of the radial air-pipe attachments near the top of the cone and of the air-valve outside of the air-lift .tube at the bottom may obviate the difficulty to some extent; but the action of the radial air-pipes on the cone-sides is that -of a sand-blast, and their continuous use cuts through the tanks. Moreover, even when these pipes are used, some pulps will pack tightly below them in the cones. Under such conditions the use of Pachuca tanks with intermittent filling and discharging becomes a troublesome process. Time is lost in ,starting agitation; large quantities of compressed air are wasted; pulp is blown over the tank-tops; and not infrequently it may be necessary to dig out the bottoms of tanks by hand. This trouble is the only important one occurring in the use of Pachuca tanks; and, since it is caused by intermittent filling, the .arrangement of a continuous flow of pulp from tank to tank,

Aug 1, 1911

By Arthur Winslow

Introductory.—The following paper is based upon a report on the lead- and zinc- deposits of Missouri, prepared for the State Geological Survey, which is now being printed. This report is the outcome of work prosecuted by the writer, assisted by Mr. J. D. Robertson, during the past five years. The studies in the State were supplemented by examinations of the similar ore deposits in Wisconsin and Arkan- sas. The report will contain in all about 800 pages, and the aim has been to make it complete and exhaustive, especially in descriptive matter. Naturally, only a brief outline can be presented here, and the reader is referred to the report itself for further details. Contents. I.—History and Statistics, . . 636 II.—Topography of the Region, . 639 III.—General Geology, . . .639 The Archean, . . .639 The Algonkian, . . 640 The Silurian, . . .640 The Devonian, . . 640 The Lower Carboniferous, 641 Tie Coal Measures, . 641 The Tertiary, . . .641 Structural Geology,. . 642 IV.—The Ore-Deposits, . . .643 Geologic Distribution, . 643 The Forms of the Ore-Bodies, . . .641 The Composition if the Ore-Bodies, . . .645 Gangues, . . . 645 Minerals, . . .618 Paragenesis of Minerals, . . . 651 The Structure of the Ore-Bodies, .... 651 V.—Descriptions of Types, . . 652 The Eagle Mines, . . 652 Shaft No. 23, . . 652 The Western Zinc Company or Oswego Lands, 651 The Gobar and Tomlinson Shaft, . 655 The Alba Company's Mine, 656 The Victor Mine, . . 658 The Bonne Terre Mines, . 660 General Geology, . 660 The Ore-Bodies, . 661 The Vallé Mines, . . 664 The Garatee Mines, . 664 The Corn-Stalk Diggings, . . .665 The Virginia Mine, . 666 The Conlogue Mine, . 667 VI.—The Mode of Formation of the Ore-Bodies, . . 670 The Formation of the Cavities. . . . 670 The Filling of the Cavities, . . . .675 The Formation of the Breccia Deposits, . . 673 The Formation of Circle Deposits, . . .674 The Impregnated Deposits of the Southeast, . 676 VII.—The Origin of the Metalliferous and Other Minerals, 676 1. Originally Deposited in Concentrated Condition, 676 2. Derived from Great Depths, . . .677 3. Original Diffusion, Supplemented by Lateral Secretion, . . . 678 4. Concentrated Through Surface Decomposition, 681

Jan 1, 1895

By E. L. Jr. Spain

This study was undertaken primarily to determine the reasons for certain varia-tions in the soundness of gravel aggregate taken from a number of widely separated points on the Tennessee River. Under laboratory tests, concrete made with these various aggregates it some cases exhibited marked differences in specific gravity, crushing strength and durability. Gravel was studied in detail from Chattanooga to the mouth of the river and to a lesser extent from Chattanooga to Knoxville. The causes of variation were determined, and variational curves were constructed, which accurately predict the composition of aggregate at any point on the river and therefore its relative suitability for use in concrete. The aggregate at any point is suited for making sound concrete; the variance of suitability is due to varying percentages of sandstone and weathered material, which are less sound than other constituents. INTRODUCTION When it is stated that the aggregate from one point is inferior to that from another, it must not be construed to mean that the gravel is unfit for use. The classification upon which such aggregate ratings are based is largely arbitrary, thus inferiority or superiority is merely relative. Samples of gravel were selected from stockpiles at the dams of the Tennessee Valley Authority under construction, from the stockpiles of private companies along the river, and from samples taken by the gravel-exploration barge of the T. V. A. One hundred or more gravels of each size studied were selected at random by taking small handfulls while walking around the piles. These were separated according to the differ-ent mineral or rock constituents present, and the percentage of each constituent was obtained by counting. At least three such samples were taken from each size, and all checked with one another within a few per cent. The results were then averaged. In order to check on the accu-racy of such sampling, a whole sample was taken from one point after the gravel was thoroughly mixed. The two methods gave approximately identical results.

Jan 1, 1937

By Frederick Jr. Prime

THE first catalogue of Geological Reports of the United States was prepared by Prof. O. C. Marsh, and published in the American Journal of Science and Arts for 1867, vol. xliii, second series. Since then the list has more than doubled, and it was thought that the publication of a new catalogue, brought down to date, would be useful to many of the members of the Institute of Mining Engineers. The compiler will be most thankful to have any omissions or inaccuracies in the list sent to him, to be published as a supplement in the next volume of the Transactions. Especially to have the correct title, number of pages, plates, and maps of any volume on the list to which an * is prefixed, as he has been unable to personally consult such works. A preliminary list was issued last February, which has been almost doubled by the kindness of many friends. The writer desires more especially to express the obligations he is under to the following gentlemen The Chief of Engineers, U. S. A.; Principal Dawson, Mr. G. M. Dawson, Drs. B. J. Harrington and T. Sterry Hunt, of Montreal; Mr. H. Engelmann, of La Salle, Ill.; Dr. F. V. Hayden and Prof. J. W. Powell, U. S. Department of the Interior ; Prof. E. W. Hilgard, University of California; Prof. Henry Y. Hind, Windsor, N. S.; Prof. C. H. Hitchcock, of Dartmouth College; Mr. Henry A. Holmes, State Librarian, Albany; Maj. Jed. Hotchkiss, Staunton, Va. ; Prof. W. C. Kerr, Raleigh, N. C.; Dr. J. S. Newberry, of Columbia College ; Prof. W. H. Pettee, of the University of Michigan ; Dr. Samuel H. Scudder, Prof. N. S. Shaler, and Prof. J. D. Whitney, of Harvard College ; Mr. Sanderson Smith and Prof. J. J. Stevenson, of New York ; Mr. Addison Van Name, of Yale College, and Lieut. Geo. M. Wheeler, U. S. Engineers. PHILADELPHIA, 907 Walnut Street, October 1st, 1879.

Jan 1, 1879

By Morris Cohen

Within the past two years, a number of publications have called attention to the double peaks, or stages, that appear in the hardness and strength curves of certain aging alloys. The author has shown the existence of double hardness peaks during the aging of a high-purity silver-copper alloy;' and on the basis of electrical resistance, microscopic, dilation and lattice-parameter measurements, hc concluded that the initial hardness peak occurs prior to precipitation while the secondary hardening is due to precipitation. It was suggested that the general mechanism of age-hardening involves two consecutive processes, the first consisting of nucleus or knot2 formation, and the second consisting of actual precipitation and particle growth. It was further held that the two stages are interdependent, but because of nonuniform precipitation they may overlap each other to an extent that increases as the aging temperature is raised. At high aging temperatures, the effect of the first stage cannot be detected because of the rapid occurrernce of precipitation. The general theory of age-hardening recently presented by Dr. M. L. V. Gayler3 is in close agreement with the picture outlined above. With reference to work done on duralumin, copper-beryllium and copper-silver alloys, Dr. Gayler also concluded that age-hardening takes place in two consecutive steps: first, diffusion (in which the solute atoms migrate to certain crystallographic planes), and then precipitation. However, W. L. Fink and D. W. Smith4 have shown that the double aging peaks that appear in the strength curves of high-purity aluminum-copper alloys may be explained without recourse to pre-precipitation phenomena. By means of very careful metallographic technique, Fink and Smith demonstrated that during aging the precipitation takes place at an accelerated rate along the grain boundaries and slip planes as a result of the plastic deformation caused by the drastic quench from the solution heat-treatment temperature. The general precipitation occurs at a

Jan 1, 1939

By Morris Cohen

Within the past two years, a number of publications have called attention to the double peaks, or stages, that appear in the hardness and strength curves of certain aging alloys. The author has shown the existence of double hardness peaks during the aging of a high-purity silver-copper alloy;' and on the basis of electrical resistance, microscopic, dilation and lattice-parameter measurements, hc concluded that the initial hardness peak occurs prior to precipitation while the secondary hardening is due to precipitation. It was suggested that the general mechanism of age-hardening involves two consecutive processes, the first consisting of nucleus or knot2 formation, and the second consisting of actual precipitation and particle growth. It was further held that the two stages are interdependent, but because of nonuniform precipitation they may overlap each other to an extent that increases as the aging temperature is raised. At high aging temperatures, the effect of the first stage cannot be detected because of the rapid occurrernce of precipitation. The general theory of age-hardening recently presented by Dr. M. L. V. Gayler3 is in close agreement with the picture outlined above. With reference to work done on duralumin, copper-beryllium and copper-silver alloys, Dr. Gayler also concluded that age-hardening takes place in two consecutive steps: first, diffusion (in which the solute atoms migrate to certain crystallographic planes), and then precipitation. However, W. L. Fink and D. W. Smith4 have shown that the double aging peaks that appear in the strength curves of high-purity aluminum-copper alloys may be explained without recourse to pre-precipitation phenomena. By means of very careful metallographic technique, Fink and Smith demonstrated that during aging the precipitation takes place at an accelerated rate along the grain boundaries and slip planes as a result of the plastic deformation caused by the drastic quench from the solution heat-treatment temperature. The general precipitation occurs at a

Jan 1, 1939

By E. N. Aqua, C. M. Owens

The microstructure in cold-rolled Zircaloy-4 sheet has been characterized by transmission electron microscopy and X-ray diffraction line-broadening techniques. The rate of work hardening is measured in terms of microstrains, particle sizes, micro hardness, the tensile yield strength. The tensile yield strength of Prestrained (less than 10 pet) Zircaloy-4 sheet is found to be a linear function of the square root of the dislocation density, us predicted by work-hardening theories. ZIRCALOY is one of the most important structural alloys for nuclear reactor applications.''2 In order to understand the effects of the nuclear environment on Zircaloy structural members, the preirradiation microstructure must be characterized. This report will describe the substructure existing in cold-rolled Zircaloy-4 sheet as observed by electron microscopy and by X-ray diffractometry. I) EXPERIMENTAL PROCEDURE Commercial Zircaloy-4 strip was cold-rolled and annealed in argon at 760°C for 1 hr. The annealed sheet was again cold-rolled to a maximum of 50 pct reduction in thickness with segments of the strip being retained after 2.5, 5, 10, and 20 pct reductions. One-inch-square portions were chemically polished (50 parts HNO3, 50 parts H2O, 10 parts HF) and mounted onto lucite blocks using double-sided tape to prevent bending during handling. Thin foils suitable for transmission electron microscopy were prepared from each of the sheet samples. The sheets were mechanically polished through 600-grit paper to a 3 to 4 mil thickness and were chemically polished by immersion for 1 to 2 min in a solution containing: 50 parts HNO3, 50 parts H2O, and 10 parts HF, and rinsed in distilled water. The final metallographic procedure was to electropolish for less than 10 sec with an electrolyte of 10 parts perchloric acid and 90 parts glacial acetic acid, at 20 v, at room temperature using stainless-steel point cathodes and a vigorous stirring action. These foils were examined in a Philips EM 200 electron microscope using a 100-kv accelerating voltage.

Jan 1, 1968