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The Round Table on Qualities of Pig Iron, under the auspices of the Joint Committee on Qualities of Pig Iron, which is made up of members of the American Institute of Mining and Metallurgical Engineers, the American Foundrymen's Association, the American Society for Testing Materials, the Gray Iron Institute, and the Malleable Iron Institute, was held at the Palmer House, Chicago, III., on Oct. 1, 1935. Prcoeedings R. H. SwEEtseR,* New York, N. Y.—Seven years ago last June, in Chicago, we had a round table on qualities of pig iron1, and at that time the foundrymen were out with their battle-axes for the blast-furnace men, and the open-hearth men were doing the same thing. After that meeting there was really a determined effort to find out about the qualities of pig iron, and great progress has been made all along the line. This afternoon we want to have a frank discussion of the qualities of pig iron, whether it is the molten pig iron going into the steel plant, or cold pigs going to the different foundries. We ought to hear something from Dr. J. T. MacKenzie, who is chairman of the Joint Committee, and from Mr. R. E. Kennedy, the Technical Secretary of the American Foundrymen's Association. J. T. MacKEnzie,† Birmingham, A1a.—As a result of that meeting in Chicago, there was considerable agitation in the Foundrymen's Association to develop a set of tests for pig iron. One of the difficulties was that nobody talked the same language on shrinkage, draws, live iron, dead iron, and so forth, which were the main complaints against pig iron. By request of a committee of the Foundrymen's Association, the Bureau of Standards ran a comprehensive set of tests that did develop the principles governing the optical pyrometer as applied to cast iron and pig iron. Then the Bureau went on further with the fluidity test, and developed a method for the absolute changes of volume at the freezing point. There is one serious gap in the yardstick, which has never been developed, and that is the tendency to draws from heavy sections to light. Everyone who has worried about the differences of section, and sponginess in changes of section, realizes that the

Jan 1, 1936

The Round Table on Qualities of Pig Iron, under the auspices of the Joint Committee on Qualities of Pig Iron, which is made up of members of the American Institute of Mining and Metallurgical Engineers, the American Foundrymen's Association, the American Society for Testing Materials, the Gray Iron Institute, and the Malleable Iron Institute, was held at the Palmer House, Chicago, III., on Oct. 1, 1935. Prcoeedings R. H. SwEEtseR,* New York, N. Y.—Seven years ago last June, in Chicago, we had a round table on qualities of pig iron1, and at that time the foundrymen were out with their battle-axes for the blast-furnace men, and the open-hearth men were doing the same thing. After that meeting there was really a determined effort to find out about the qualities of pig iron, and great progress has been made all along the line. This afternoon we want to have a frank discussion of the qualities of pig iron, whether it is the molten pig iron going into the steel plant, or cold pigs going to the different foundries. We ought to hear something from Dr. J. T. MacKenzie, who is chairman of the Joint Committee, and from Mr. R. E. Kennedy, the Technical Secretary of the American Foundrymen's Association. J. T. MacKEnzie,† Birmingham, A1a.—As a result of that meeting in Chicago, there was considerable agitation in the Foundrymen's Association to develop a set of tests for pig iron. One of the difficulties was that nobody talked the same language on shrinkage, draws, live iron, dead iron, and so forth, which were the main complaints against pig iron. By request of a committee of the Foundrymen's Association, the Bureau of Standards ran a comprehensive set of tests that did develop the principles governing the optical pyrometer as applied to cast iron and pig iron. Then the Bureau went on further with the fluidity test, and developed a method for the absolute changes of volume at the freezing point. There is one serious gap in the yardstick, which has never been developed, and that is the tendency to draws from heavy sections to light. Everyone who has worried about the differences of section, and sponginess in changes of section, realizes that the

Jan 1, 1936

By G. H. Clevenger

(Continuing the discussion of the paper of James Johnston, presented at the New York meeting, February, 1914, and printed in Bulletin No. 85, January, 1914, pp. 107 to 133.) This paper cannot fail of being of great interest and value to all who are interested in the cyanide process, on account of the important developments which it records. Mr. Johnston is to be commended for the large amount of detail which he gives, and the company and its management for permitting the publication of data of this character, which while of great value to others could well be considered private property. It might be discussed from a number of standpoints: First, as an example of recent practice in mill and cyanide plant construction; second, the mill practice; third, the cyanide practice; and fourth, the new features in cyanide treatment involved. Perhaps a more vivid way of expressing it would be : First, the equipment or tools with which the various operations are carried on, are they the best and most efficient which could have been selected for their respective uses; and, second, is the best use in every case made of these tools? It may be well inquired is the highest possible recovery of silver made at the lowest cost per ounce recovered? For after all, the making of the greatest ultimate profit is inseparably associated with successful metallurgical practice; there must therefore be at all times a careful balance maintained between recovery and cost of obtaining it. I wish to call attention in a very general way to the equipment used and to an anticipation of questions which are bound to arise in this connection. However, the. bulk of my discussion will be confined to the presentation of certain additional data, together with a more or less general discussion showing the line of development which leads up to the present practice and .the applicability of certain features of it to similar problems elsewhere. There are a number of vital points of broad general interest involved in Nipissing low-grade practice upon which metallurgists will by no means be agreed to which I wish to call particular attention in the hope that it will lead to the presentation of data y others of practice in other districts which will' assist in reconciling this divergence of opinion.

Jan 7, 1914

By L. W. Page

PrEvious to the introduction of the motor vehicle the broken stone or macadam' road met the conditions of rural horse-drawn traffic better than any other type of road, but under fast motor traffic it has been proved to be quite unsatisfactory, and necessitates high maintenance charges. Such a road depends for its success upon the fact that the rock dust fills the voids between the stones and acts as a cement or binder. Under ideal conditions it should be constructed of rock so suited to the volume and character of horse traffic that only enough fine dust is worn from the stones of which the road is composed to take the place of that carried off by wind and rain; and when these conditions are met, the fine dust resulting from the wear of traffic forms with the stone a smooth, impervious shell, shedding the surface water and protecting the foundation. With increase in the number and speed of motor vehicles, however, it was soon found that the cost of maintenance also increased, until at the present day highway engineers consider the old method of constructing and maintaining broken-stone roads increasingly inadequate, and are introducing every known type of binding material other than rock dust to cement the stone together. Among the most prominent types of products in use are those produced from our various petroleums. That the value of modern methods of road preservation was appreciated in this country much earlier than we have been accustomed to believe is demonstrated by the recent revival of an old patent which was granted to one John Martineau, of Elbridge, N. Y., in 1834. Petroleum had, of course, not been discovered at that time, but he claims as his invention and improvement "The application of tar, turpentine, or any of that class of tenacious, cohesive substances, reduced before use to a fluid state, and that state used as a cement, to apply to, and combine with sand, gravel, pebbles, and pulverized stone, such as is used for a Mc-Adam road, or cobble stone, the interstices of coarser material being in all cases filled,'as well as may be, with sand and gravel and cemented with tar or turpentine, to form the wearing face or surface of streets,

Jan 1, 1915

By Felix B. Shay

The Agua Fria mine is in eastern Honduras at Lat. 140" 06' N., Long. 86" 36' W. Danli, the seat of the local municipal government, is the nearest town. The property is approximately 44 miles east of Tegucigalpa, the terminus of a truck road from the Pacific coast. The mine lies at an altitude of 3300 ft. with surrounding elevations as high as 6000 feet. For 20 years the oxidized croppings of the Agua Fria vein had been worked intermittently when in 1927 an attempt was made to open the property. A shaft was sunk 300 ft. and considerable ore was blocked out, but before a mill could be installed financial difficulties arose and the mine reverted to the original owners. Erle Y. Halliburton, of Los Angeles, purchased the property in 1934. At that time a careful consideration of all factors involved showed that air transport was the only practical method of moving the equipment and machinery necessary to commence production. The other alternative was by muleback, which required sectionalizing all equipment to a maximum load of 200 lb., and during the rainy season this type of freighting was subject to serious delays. It was decided to purchase a trimotor Ford powered by three Pratt and Whitney Wasp B motors developing 400 hp. each. There were several reasons for the choice: (1) this type of plane was available at a reasonable price, owing to its replacement by faster models on most of the airlines in the United States; (2) the ship was capable of carrying a pay load of 3000 Ib. over the required distance; (3) since this airplane had been widely used there would be no difficulty in securing competent personnel or in purchasing spare parts. It was necessary to rebuild the plane for cargo servicc. The windows were removed and the fuselage was entirely covered. A hatch was cut in the top of the fuselage to receive heavy crane loads and pieces of freight that were too large or too long to go through the rear door. The seats were removed and the interior of the plane was lined with Duralumin sheets. A heavy-duty landing gear was installed and the floor was reinforced. The nearest site for an airport was two miles north of the mine. The necessary grading was done by a small track-type tractor with a wheeled grader, which was brought in overland. Six weeks was required for bring-

Jan 1, 1940

By F. R. Archibald, C. F. Jackson

THE prospect of winning aluminum from clay was recorded almost a century ago at a time when the metal was no more than a curiosity.? As the industry developed, and it has probably developed faster than that of any other metal, the expanding need for raw materials was adequately met by the ample supplies of bauxite ore. As with the other metals older in industry, however, lower grade ores have gradually entered the raw-material field through improvements in ore dressing, insufficienoy of high-grade ore supplies, favorable geographic location, or national necessity for domestic supply. So with aluminum, or alumina, which has been established as the requisite intermediate, the time may have come when a satisfactory process, with favorable location and suitable raw materials, can hold a sound place both in metallurgy and economics. It is the purpose of this paper to describe the Ancor process and its proposed application in treatment of clay in a plant now under construction at Harleyville, South Carolina, by the Defense Plant Corporation. DEVELOPMENT OF THE ANCOR PROCESS The Ancor process has developed through successive stages of laboratory investigation, pilot-plant demonstration using nepheline syenite and pilot-plant demonstration using kaolin-type day from South Carolina, and is now in preparation for unit trial on an operating plant basis using the latter material. The laboratory studies were carried out over a number of years in the laboratory of the American Nepheline Corporation in Rochester, N. Y., and for the same company in the ore-dressing laboratory of Beattie Gold Mines, Que. Ltd. at Duparquet, Quebec. Both companies are associated with Ventures Ltd., Toronto, and its associated American companies. The work was originally undertaken with a view to recovery of alumina and alkalies from nepheline syenite as an adjunct to the American Nepheline Company's established business in the glass and ceramic trades, but as a process developed the possibility of application to clay and other aluminous raw materials become apparent and the laboratory studies were broadened to include these as well. Under the more pressing impetus of wartime needs and possibilities, pilot-plant operations were undertaken at the Canadian Bureau of Mines Ore Dressing Laboratories in Ottawa, and for purposes of demonstration under joint sponsorship of the Canadian Bureau of Mines, The American Nepheline Corporation, and The Aluminum Company of Canada Ltd.

Jan 1, 1944

By Felix B. Shay

The Agua Fria mine is in eastern Honduras at Lat. 140" 06' N., Long. 86" 36' W. Danli, the seat of the local municipal government, is the nearest town. The property is approximately 44 miles east of Tegucigalpa, the terminus of a truck road from the Pacific coast. The mine lies at an altitude of 3300 ft. with surrounding elevations as high as 6000 feet. For 20 years the oxidized croppings of the Agua Fria vein had been worked intermittently when in 1927 an attempt was made to open the property. A shaft was sunk 300 ft. and considerable ore was blocked out, but before a mill could be installed financial difficulties arose and the mine reverted to the original owners. Erle Y. Halliburton, of Los Angeles, purchased the property in 1934. At that time a careful consideration of all factors involved showed that air transport was the only practical method of moving the equipment and machinery necessary to commence production. The other alternative was by muleback, which required sectionalizing all equipment to a maximum load of 200 lb., and during the rainy season this type of freighting was subject to serious delays. It was decided to purchase a trimotor Ford powered by three Pratt and Whitney Wasp B motors developing 400 hp. each. There were several reasons for the choice: (1) this type of plane was available at a reasonable price, owing to its replacement by faster models on most of the airlines in the United States; (2) the ship was capable of carrying a pay load of 3000 Ib. over the required distance; (3) since this airplane had been widely used there would be no difficulty in securing competent personnel or in purchasing spare parts. It was necessary to rebuild the plane for cargo servicc. The windows were removed and the fuselage was entirely covered. A hatch was cut in the top of the fuselage to receive heavy crane loads and pieces of freight that were too large or too long to go through the rear door. The seats were removed and the interior of the plane was lined with Duralumin sheets. A heavy-duty landing gear was installed and the floor was reinforced. The nearest site for an airport was two miles north of the mine. The necessary grading was done by a small track-type tractor with a wheeled grader, which was brought in overland. Six weeks was required for bring-

Jan 1, 1940

By Carl Zapffe

The object of the Bradley process is to free manganese oxide from its associated gangue and separate the contained iron oxide by dissolving the manganese and precipitating it from the solution. This results in producing two oxides as concentrates, the one to be converted into a manganese sinter and the other into an iron sinter. The manganese sinter may be made to contain as high as 70 per cent. inanganese and as low as 1 per cent. silica, with phos'phorus not to exceed 0.02 per cent, and from that figure downward to about 0.005 per cent., and with sulfur at 0.007 per cent. The iron sinter contains about 2.50 per cent. manganese, making the total recovery of the manganese 98 per cent. The method involves selective roasting, which converts the manganese into a form in which it is soluble in an aqueous solution of ammonium sulfate, then precipitating the manganese as a hydrate by using ammonia gas, then stabilizing and washing the hydrate, followed by sintering; concurrently most of the iron oxide is converted by roasting into an insoluble form and becomes a residue with magnetic qualities, which makes possible the recovery of much of the iron in the ore. Leaching manganese by using sulfur dioxide gas was shown possiblc Inany years ago. Mr. Bradley tried it for a year, working in conjunction with the original experimenters of that method, and found that while relatively pure inanganese oxide could be produced, the likelihood of developing a commercial process along this line was not very encouraging. He also attempted leaching with nitric and sulfur acids, but the cost of recovery mounted and the quality of the product was not as good Mr. Bradley tried nearly every leaching method proposed, and the expen-ments were made on a large scale in the spacious laboratories of John C. Wiarda & Co., in Brooklyn, N. Y. Insufficient encouragement was discernible in the results obtained. Upon the suggestion of N. Arthur Laury, of John C. Wiarda & Co., Bradley undertook using arnrnoniurn sulfate. Because a high rate of recovery appeared feasible, Bradley planned the erection of a 4-ton pilot plant at the State of Minnesota Mines Experiment Station, at Minneapolis. The results of that work are described in this treatise.

Jan 1, 1929

By P. G. Winchell, R. J. Russell

The distribution of displacements of originally plane surfaces by an invariant-plane strain has been analyzed statistically. The displacement ratio (the magnitude of the displacement of a point originally a unit distance from the invariant plane) can be determined from an analysis either of tilts of random surfaces or of displacements of random scratches scribed on a randowz surface. In either case the mean of the tangent of the observed displacement angle is related to the displacement ratio, and the number of observations used in determining the mean is related to the confidence limits placed on the estimate of the displacement ratio. In estimating the effect of applied stress on a phase transformation whose displacement effects can be approximated as an invariant-plane strain,* the dis- placement ratio of the invariant-plane strain is of primary importance. Two procedures for determining such displacement ratios are considered here. In the tilt method the measured quantity is taken to be the angle through which a random polish plane is rotated by the invariant-plane strain. In the scratch method the measured quantity is taken to be the angle between the original direction of a random scratch in a random polish plane and the projection of its final direction in the polish plane. In order to obtain precise results from either of the methods, it is necessary to measure the relative volume change associated with the strain in a separate experiment. TILT METHOD A locally homogeneous invariant-plane strain, P, with displacement ratio, S, may be written&apos; where ; and < are unit vectors indicating the displacement direction and invariant-plane normal, respectively, as pictured in Fig. 1. Eq. [I] describes a uniaxial strain if the direction of displacement is parallel to the invariant-plane normal and a pure shear strain if the displacement direction is perpendicular to the invariant-plane normal. The original orientation of the random polish plane relative to the invariant plane and to the displacement direction is shown in Fig. 2. The angle 03 between < and u is related to the relative volume change, ?V/V, and to the displacement ratio by As a result of the invariant-plane strain, the polish plane is rotated about its intersection with the invariant plane by the angle y, which is always taken to be positive. The tangent of this angle in terms of the above parameters is

Jan 1, 1967

By William B. Plank

ENROLMENT data given in this report of the seventh study of the schools by the Mineral Industry Education Division reveals the critical situation in the mineral engineering schools of the United States. Complete figures for the year 1942-43 show that at that time, about one year after Pearl Harbor, the enrollment of mineral engineers was 6385 or 30 per cent less than in 199441. By October 1943, however, enrollment had dropped to 2050, as reported in the Journal of Engineering Education of January 1944. This was a further reduction of 68 per cent in one year, or 77 per cent in three years. With accelerated programs in effect during the current year, with many graduations since last October, and with the military forces taking practically all the high school graduates, the present enrollment is, of course, much lower than the 2050 above given. There are no late data on the exact situation. In Canada, the same situation exists in the mineral engineering schools, only

Jan 1, 1944

By William L. Fink, Kent R. Van Horn

Zinc is one of the effective elements introduced to enhance the strength of aluminum. This strengthening is principally attributable to the high solid solubility of zinc in aluminum and the pronounced variation of solubility with temperature. Consequently an accurate determination of the solid solubility curve is desirable. The solid solubility relations have been studied by numerous investigators. Shepherd1 first established the existence of a solid solution region at the aluminum end of the diagram (-v phase) by specific volume and microscopic determinations. Bauer and Voge12 published a constitutional diagram which showed the limits of solid solubility as determined by thermal and microscopic methods. Hanson and Gayler3 presented the aluminum-zinc diagram which is now most generally accepted (Fig. 1). Chill-cast samples were given thermal treatments designed to obtain equilibrium conditions, quenched, and microscopically examined. The solubility was placed between 15 to 20 per cent at 60" C., 20 to 22 per cent at 140" C. and 36 to 38 per cent at 270" C. Sander and Meissner decidedly modified the limits of the -y phase field of Hanson and Gayler&apos;s diagram by using similar methods on chill-cast specimens annealed for a shorter period of time. Tanabe,s utilizing dynamic hard-ness, electrical conductivity and dilatometric measurements of specimens at temperature, obtained values comparable to Hanson and Gayler&apos;s at room temperature, but appreciably lower at higher temperatures. Nishimura6 concluded from age-hardening results of aluminum-zinc alloy chill castings, which had been quenched from 400" to 500" C., that the solubility of zinc in aluminum at room temperature is less than 5 * Metallurgical Division, Aluminum Research Laboratories. 1 E. S. Shepherd: Aluminum-Zinc Alloys, Jnl, phys. Chem. (1905) 9, 504. 2 0. Bauer and 0. Vogel: Aluminum-Zinc Alloys, Int. Jn1. Melallog. (1916) 8, 101. 3 D. Hanson and M. V. L. Gayler: A Further Study of the Alloys of Aluminum and Zinc. Jnl. Inst. Met. (1922) 27, 267. 4 W. Sander and K. L. Meissner: ZII~ Kenntnis der Konstitution der Aluminium-Zinklegierungen. Ztsch. f. Metallkunde (1922) 14, 385. 4 T. Tanabe: Studies in the Aluminum-Zinc System, Jnl. Inst. Met. (1924) 32, 415 6 H. Nishimura: On the Age-Hardening of Aluminum-Rich Al-Zn Alloys. Mem. Kyoto Imp. Univ. (1924) 3, 133.

Jan 1, 1932

By F. L. Bosqui

Discussion of the paper of F.* L. Bosqui, presented at the San Francisco meeting, September, 1915, and printed in Bulletin No. 101, May, 1915, pp. 997 to 1033. SIDNEY J. JENNINGS, New York, N. Y.-I notice Mr. Bosqui says that zinc dust can be used profitably. I had occasion recently to try to ship some zinc deist to South Africa, owing to the. high price of zinc in the last six or eight months and the difficulty in getting zinc sheets We were informed that the steamship companies in England refused to accept zinc dust for shipment through the tropics on the score that it was an explosive mixture. C. W. MERRILL, San Francisco, Cal.-In the early days zinc dust was packed in wooden casks. The steamers at that time were very chary of transporting it. It was put on the deck in the wooden casks, and if the zinc dust got wet it exploded. Since that time we have used hermetically sealed cases, in which case there is no risk whatever in its transportation.. This rule of the steamship companies is perhaps another sample of their ultra-conservativeness. HENNEN JENNINGS, Washington, D. C.-Unfortunately, I have not yet read Mr. Bosqui&apos;s paper, but believing it might interest you to know something of the beginning of the cyanide process on the Rand, I will speak briefly as to my own knowledge and experience of the early initiation of this process in South Africa. I took the position of consulting engineer of H., Eckstein, the parent firm of H. Eckstein & Co., and a branch of the firm of Wernher, Belt ,C Co., at Johannesburg, in December, 1889, and at that time the Robinson Co. managed by them was the premier company of the fields. Up to this date plate amalgamation and catchment of a small percentage of concentrates by blankets, and in a few instances Frue vanners, were the main gold-saving devices used and had obtained an extraction&apos; of only about 65 per cent of the gold contents of the ore. Also at that time the orebodies were seen to be changing from oxidized deposits to pyritic at varying depths from 50 ft. to 300 ft. below the surface, and uneasiness was felt as to future recovery. The deepest exploitation at any of the mines was not much below 300 ft.

Jan 12, 1915

Elected Died 1895 *ABBOTT, AI ATTHUR 1908 1882 *ABBOTT, ARTHUR V 1906 1905 * ABE, MASAYOSHI 1909 1903 * ADAMS, CHARLES C. 1905 1906 * ADAMS, JOHN C. 1913 1905 * ADAMS, WILLAMS 1909 1903 * ADAMS, W. EDWARDS 1910 1884 *ADDY, MATTHEW 1896 1906 * AFFLECK, WILLIAM A. 1911 1889 * AKERS, WILLIAMS A. 1906 1905 * ALABASTER, RUPPERT C. 1911 1899 * ALBERGER, LOUIS R. 1911 1894 *ALLEN R B 1896 1905 * ALLEN, R. SCOTT 1906 1874 * AMIOT, H. 1892 1886 *AMSLER, CARL 1894 1898 ** ANDRSON, JOHN W 1905 1895 *ÅNGSTROM, CARL 1901 1887 * ARCHBALD, JAMES 1910 1900 * ARLETT, GEORGE H 1906 1895 *ARMSTRONG, JOHN F 1898 1882 *ARNOLDS, HUGO 1886 1875 *ASHBURNER, CHARLES A 1889 1872 *ASIIBURNER, WILLIAM 1887 1883 *ATKINS, C M , JR 1885

Jan 1, 1917

By G. Carman Ridland

Front Range, Colorado: The majority of the rocks comprising the Front Range of Colorado are pre-Cambrian schists, gneisses, and intrusives which have been elevated to form part of the Southern Rocky Mountain physiographic province. The region is noted mainly for its production of gold and silver, but ores of tungsten, fluorspar, uranium, copper, and iron have been worked. Geological literature1-&apos; describes pitchblende and other radioactive minerals occurring at Jamestown, Boulder County; Central City, Gilpin County; and Lawson, Clear Creek County (fig. 1). These three adjoining G. CARMAN RIDLAND, Member AIME, is a Consulting Geological Engineer, New York, N. Y. San Francisco Meeting, February 1949. TP 2738 IL. Discussion of this paper (2 copies) may be sent to Transactions AIME before Feb. 28, 1950. Manuscript received March 30, 1949. counties cover most of the highly mineralized section of the Front Range which extends from Jamestown to Breckenridge. As far as the writer is aware, uranium has been found only in the portion northeast of Lawson. Silver Deposits at Caribou Hill: The historic silver deposits of Caribou Hill, located approximately half way between Jamestown and Central City, and 35 miles in a straight line northwest of Denver, appeared particularly intriguing as an area to prospect for uranium for the following reasons: here exists an isolated group of high-grade silver veins in the center of a mining district containing occurrences of uranium, and, in two of the well-known uranium deposits of the world, those at Great Bear Lake, Canada, and Joachimsthal, Czechoslovakia, uranium is associated with silver in similar fissure veins. An exploration program, conducted in the spring of 1945, directed special attention to Caribou Hill and was rewarded with the discovery of heavy, canary-yellow stained specimens of&apos;pitchblende. The veins are confined to shear zones cutting a north-south, elongated quartz-monzonite stock of Tertiary (?) age lying in the axis of a major anticline of the Idaho Springs biotite schist, the oldest pre-Cambrian formation in the district. The stock is one and three-quarter miles long by more than a mile wide, and Caribou Hill is approximately at its center. The ore zones vary in width from a few inches to 15 ft, and one structure has been traced for a length of over 4000 ft. The ore minerals are galena, sphalerite, ruby silver, native silver, chalcopyrite, pyrite, and pitchblende. They occur most common-

Jan 1, 1951

By G. Carman Ridland

Front Range, Colorado: The majority of the rocks comprising the Front Range of Colorado are pre-Cambrian schists, gneisses, and intrusives which have been elevated to form part of the Southern Rocky Mountain physiographic province. The region is noted mainly for its production of gold and silver, but ores of tungsten, fluorspar, uranium, copper, and iron have been worked. Geological literature1-&apos; describes pitchblende and other radioactive minerals occurring at Jamestown, Boulder County; Central City, Gilpin County; and Lawson, Clear Creek County (fig. 1). These three adjoining G. CARMAN RIDLAND, Member AIME, is a Consulting Geological Engineer, New York, N. Y. San Francisco Meeting, February 1949. TP 2738 IL. Discussion of this paper (2 copies) may be sent to Transactions AIME before Feb. 28, 1950. Manuscript received March 30, 1949. counties cover most of the highly mineralized section of the Front Range which extends from Jamestown to Breckenridge. As far as the writer is aware, uranium has been found only in the portion northeast of Lawson. Silver Deposits at Caribou Hill: The historic silver deposits of Caribou Hill, located approximately half way between Jamestown and Central City, and 35 miles in a straight line northwest of Denver, appeared particularly intriguing as an area to prospect for uranium for the following reasons: here exists an isolated group of high-grade silver veins in the center of a mining district containing occurrences of uranium, and, in two of the well-known uranium deposits of the world, those at Great Bear Lake, Canada, and Joachimsthal, Czechoslovakia, uranium is associated with silver in similar fissure veins. An exploration program, conducted in the spring of 1945, directed special attention to Caribou Hill and was rewarded with the discovery of heavy, canary-yellow stained specimens of&apos;pitchblende. The veins are confined to shear zones cutting a north-south, elongated quartz-monzonite stock of Tertiary (?) age lying in the axis of a major anticline of the Idaho Springs biotite schist, the oldest pre-Cambrian formation in the district. The stock is one and three-quarter miles long by more than a mile wide, and Caribou Hill is approximately at its center. The ore zones vary in width from a few inches to 15 ft, and one structure has been traced for a length of over 4000 ft. The ore minerals are galena, sphalerite, ruby silver, native silver, chalcopyrite, pyrite, and pitchblende. They occur most common-

Jan 1, 1951

By D. Mizer, J. B. Clark

In a recent investigation of the entire magnesium-yttrium phase diagram, Gibson and Carlsonl report the maximum solid solubility of yttrium in magnesium as 8.0 wt pct Y at 1050°F (565°C). However, independent studies of the precipitation in magnesium-yttrium alloys, 2 conducted prior to the publication of the above phase diagram, indicated a greater solid solubility of yttrium in magnesium. Accordingly, the magnesium-rich region of the diagram was re-investigated to determine more accurately the liqui-dus, solidus, and solvus of the magnesium solid solution in this system. Metallography and thermal analysis were chosen as the best corroboratory methods for accurately determining this region of the diagram. A magnesium-yttrium master alloy was prepared from yttrium of 99.9 pct purity and singly sublimed magnesium of 99.9 pct purity. Subsequently, the twelve magnesium-yttrium alloys shown in Fig. 1 were prepared using standard alloying procedures for magnesium. Metallographic samples of the alloys were heat treated under an SO, atmosphere in an electric furnace capable of control within ±3oF of the desired temperature. Alloy samples for the metallographic determination of the solvus, and for the precipitation studies were solution treated at 1000° F for 16 hr. Subsequent aging times for the solvus determination varied from a minimum of 6 hr for the higher temperatures up to 816 hr for lower temperatures. Periods of 30 min at temperature were used to generate liquation for the metallographic placement of the solidus and eutectic horizontal. The liquidus and the eutectic horizontal were determined by thermal analysis. Simple time-temper- ature heating and cooling curves were obtained from 10-g alloy samples heated and cooled in a well-insulated electric furnace. An Iron-Constantan thermocouple was placed in direct contact with the sample. The thermocouple did not contaminate the alloy sample since metallographic examination showed that the alloy melt did not wet or attack the thermocouple. The heating and cooling rates were approximately 5 to 8OF per min. The standard metallographic procedures for magnesium were used in polishing and etching the magnesium-yttrium alloys studied. Glycol etchant* was etchant was used to reveal precipitate in the solvus determination. The redetermined magnesium-rich region of the magnesium-yttrium diagram is shown in Fig. 1. The

Jan 1, 1962

One of the very simplest losses to overcome, and at small expense, is belt slip. To show the extent of the loss of money through slipping of the main belt alone, a chart, supplied us through the courtesy of the Cling-Surface Co., Buffalo, N. Y., is shown herewith, upon which this is easily ascertained. By glancing up and down column "D" of this chart it is evident that the "Cost of Avoidable Belt Slip per Year in Dollars" may vary all the way from the smallest sums into the thousands of dollars. Roughly, 2 per cent. of the potential power in the driving pulley of the engine is represented by "belt creep." Its loss is unavoidable because of the elasticity of the belt. This has been recognized and provided for in the chart, so the reader can go ahead and connect known values, while the intersection with column "D" gives the avoidable money loss. Simply zig-zag across the chart twice with a straight edge, as shown by the dotted lines and the money loss is immediately found. Thus if the total belt slip is 6 per cent. (column A) and the cost of coal per ton is $4 (column B), run a straight line through those two points and locate the intersection with column "C." Then from that point of intersection run over to the tons of coal burned per year (which in this instance has been stated as 1000 tons) and the cost of avoidable belt slip per year is shown by column "D" as being $160. To give a clear idea as to the meaning of "Total Belt Slip Per Cent." let us take an example. You find by means of a revolution counter that a given driven pulley is rotating only 940 times per minute. You figure that without slip it should rotate 1000 times per minute; 60 revolutions per minute, therefore, are absolutely lost. Dividing this 60 by the r.p.m. that pulley should make you get 0.060 or 6 per cent. which is the "Total Belt Slip." After having made this determination, it is a simple matter to apply it to the chart as has been done and determine the money loss per year due to such slip.

Jan 4, 1918

Discussion of the paper of J. K. FURST, presented at the Pittsburgh meeting, October, 1914, and printed in" Bulletin No. 94, October, 1914, pp. 2493 to 2514. W..McA. JOHNSON, New York, N. Y.-On discussing this paper I am open to the criticism of "bringing coals to Newcastle," as I, a zinc man, am bringing new ideas on steel to Pittsburgh. But still the view of an outsider can be valuable to the insider. Any multistage process, where each apparatus operates on its particular part of the work at a high efficiency, constitutes an advance in the state of art. But in multiplicity there can be complication and ensuing loss and inefficiency. The duplex steel process is not the pronounced success which was predicted for it by its adherents, for several of such plants have reverted to plain open-hearth methods. If we regard broadly refining processes, such as the Bessemer, open-hearth, puddling, copper refining, lead cupelling, nickel refining, we find that in general refining processes are intermittent and &apos;concentration processes are continuous. (This generalization I believe to be original with me; it was communicated to Dr. E. F. Roeber, editor, and appeared as an editorial in Metallurgical and Chemical Engineering, March, 1905.) Where we desire primarily quality in a metallurgical operation we must put a batch of metal in the furnace, work on it until we get it to the required purity, test it, and take it out; whereas, if we desire primarily quantity we shove ore into a furnace and smelt it as fast as possible, allowing conditions to make a non-uniform product provided only we get tonnage. From general commercial principles, I believe that the weak point of the duplex process is that the operation is not a money maker unless the plant is kept at. 90 to 95 per cent. of its rated capacity, or unless the Bessemerizing is done so often that it is practically continuous. For in some manner the operation should be made continuous and the control on the tonnage should be commercially flexible. The commercial rigidity of having to control purity exactly increases operating costs without a corresponding gain. Conversely, the chief reason for failure of "steel from ore direct" is that it makes a final operation continuous, which should be naturally intermittent.

Jan 4, 1915

He took a great interest in technical matters and his inclination was strongly toward research investigations. At the same time he was effective in manual and mechanical work and was generally found working side by side with the men under his direction. His nature was unselfish and he was extremely popular socially. He was a member of the Coeur d&apos;Alene Commandery, Knights Templar. Stanly A. Easton. Lieutenant.Louis Baird Louis Baird, a Lieutenant in the Royal Field Artillery of the British Army, died on the battlefield in 1915. Lieutenant Baird was born July 28, 1880, at Stirling, Scotland. His technical education was obtained at King&apos;s College, Melbourne, Australia, in 1893 to 1895, and at the Technical College at Glasgow, Scotland, in 1897 to 1900. After an apprenticeship with the Mexican J. & 8. Rec. Co. of Mexico, lasting from 1900 to 1903, he became mill superintendent for the Cia. Minera Benito, at Juarez, Zac. During the year 1905-6 he was assistant manager of the Caridelaria y Anexas, at Pinos, Zac., and from 1906 to 1907 was engineer with the Cia. Minera Jalisco, San Sebastian, Jalisco. At the time of his admission to the Institute, in 1908, he was practising as a mining engineer at Etzatlan, Jalisco, Mexico. For the next four years he practised his profession in the City of Guadalajara, Jalisco, removing, in 1913, to Ixtlan del Rio, in the State of Tepic. It was from here that he returned to England to put his services at the disposal of the British Government. The Institute is not definitely informed as to how, where, or when Lieutenant Baird met his death. iCaptain John H. Ballamy John H. Ballamy, Captain on the Regimental Staff of the 103d Engineers, was killed near Fismes, on Aug. 9, 1918. Captain Ballamy was born at Plvmouth. Pa.. in 1886 and graduated from&apos; the High School of that town in 1903. In the following year he began work as a coal miner, and at the same time began the study of mining engineering in the evening and any other spare time. He continued this diligent and energetic practice for many years. For sixteen years he continued in the employment of the Delaware, Lackawanna & Western Rai1roa.d Company&apos;s coal mining

Jan 1, 1920