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By George Hallerman, R. J. Gray

In the customary method of studying age hardening, the process of aging is interrupted by cooling the specimen and measuring its room-temperature hardness. However, the aging process may be conveniently measured while it is occurring at an elevated temperature by a series of hardness measurements at suitable time intervals. The latter method gives data void of complications that might result from processes occurring during the quench, and the data may be more indicative of the alloy's properties at elevated temperatures. The elevated-temperature hardness tester1 used in the present study employed a dead-weight loading system with a synthetic sapphire Vickers-type in-denter mounted in a molybdenum holder. The tests were performed in a vacuum of l0 to 10 torr. Hardness impressions were made by applying a 2-kg load for 15 sec. Although the hardness impressions made in the tester at elevated temperatures were measured at room temperature, the correction for thermal contraction during cooling was insignificant and therefore neglected. The two methods of obtaining age-hardening data were compared using eighteen samples of Haynes alloy No. 25* which had been annealed for 2 hr at 2250°F (1232°C). The test surfaces of the 1 by 1 by 1/4-in. samples were ground and then polished on vibratory polishers2 prior to testing. Three groups of five samples were aged at 1400°, 1650°, and 1800°F (760°, 899", and 982°C) for 4, 16, 32, 64, and 100 hr and then water-quenched. Room-temperature hardness as a function of aging time for these samples is shown in the broken lines of Fig. 1. Only one sample for each of the three temperatures was necessary to determine the hardness of the alloy at the aging temperatures with the elevated hardness tester. The specimens were heated isothermally and hardness impressions were made after various time intervals up to 100 hr. The results of these determinations were represented by solid lines in Fig. 1. Comparison of the two sets of curves shows, as expected, the hardness values determined at the aging temperatures are lower than the room-temperature hardness of the quenched specimens and the hot-hardness values reflect a strong tempera-

Jan 1, 1964

ASDIE from the John Fritz Medal, in which the Institute participates through its representation on the John Fritz Medal Board, the Institute itself has four awards it may make annually, as follows: the Robert W. Hunt Medal and Prize, the J. E. Johnson, Jr., Award, the James Douglas Medal, and the William Lawrence Saunders Medal. Robert W. Hunt Medal and Prize The partners of Robert W. Hunt established a fund which was presented to the Institute at a fitting ceremony on May 27, 1920, to establish an annual medal and a sum of money to be awarded under the following rules: 1. The award shall consist of two prizes: first of a gold medal, second of a sum of money; a certificate to accompany each prize. The money prize shall not be awarded to a member over 40 years of age, but under unusual circumstances, both prizes may be allotted to one person provided that he is not over 40 years of age. In general it will be understood that the Committee shall award the money prize to the younger men, rather than the medal. 2. The awards shall be made not oftener than once a year to that person or persons contributing to the Institute the best original paper or papers on iron and steel. The scope of the term "iron and steel" shall be determined by the subcommittee considering the awards. In general, papers dealing with the practical side of the subject have preference over those dealing with the theoretical side in recognition of the fact that Captain Hunt's main contributions to the industry have been in the improvement of production and quality of material. 3. A subcommittee of three to five, including the Chairman of the Iron and Steel Committee, shall be appointed by the Iron and Steel Committee annually to adjudge the award subject to approval. 4. The awarding committee shall submit its report to the Iron and Steel Committee at its October meeting, and the award shall be certified to the Secretary of the Institute in time to permit the presentation to be made at the Annual Meeting of the Institute. 5. The recipient of the award shall be designated "The Hunt Medallist." This prize is administered by the Iron and Steel Division. Awards of the medal have been made as follows: 1920—Robert Woolston Hunt. 1926—Charles Lewis Kinney, Jr. 1928—John A. Mathews. 1929—Edgar Collins Bain. J. E. Johnson, Jr., Award This award is made from the income of a fund of $3000 donated by Mrs. Margaret Hilles Johnson in memory of her husband, J. E. Johnson, Jr., who was a prominent engineer, author of two valuable volumes on iron blast-furnace construction and practice, vice-chairman

Jan 1, 1929

By Wayne A. Greenwalt

A method that determines venture participation when the decision maker's level of risk aversion varies according to venture profitability and risk investment is presented. The decision maker's fundamental aversion to risk is established by the selection of a desired working interest for a venture that anticipates only a discounted payout.

Jan 1, 1982

By Wolfgang Pitsch

INVESTIGATIONS on the above topic have recently been published by Shapiro and Kraussl and Jana and wayman in this journal and by Kessler and Pitsch.- Parts of the results in these papers are in good agreement with each other but there are also some results which are substantially different. The main points of these differences shall be briefly discussed in this communication. Shapiro and Krauss' measured single-surface traces of the habit planes of reversed austenite plates formed within the martensite crystals and deduced from these measurements two distinct habit planes A = (0.174; 0.309; 0.935) and B = (0.375; 0.545; 0.749) within 3 deg. Kessler and pitsch4 found instead by two-surface analysis7 one habit plane n = {0.23; 0.62: 0.75) with a real scatter of 6 deg. The latter observation of a single habit plane apart from a certain scatter is in agreement with most of the investigations of martensite transformations. The differences between these two results are so great that they cannot be explained by experimental error. The purpose of this communication is to show that the A- and B-poles of Shapiro and Krauss are due to an erroneous interpretation of a single-surface trace analysis. The difficulties in the interpretation of such single-surface trace analyses are due to the high symmetry of cubic lattices, from which it follows that there are in general twenty-four equivalent possibilities of plotting a single-surface trace in a pole figure. All these possibilities must be taken into account, when putting different traces from different plates together in order to construct the habit plane. Alternatively the poles of all the traces may be plotted in a unit triangle. This is done in Fig. 1 with twenty-nine traces of different reversed austenite plates, all of this were measured by Shapiro and Krauss in the same plane of a single martensite ther traces taken from Fig. 13 in the Shapiro and Krauss paper' which were determined by electron diffraction. The traces in Figs. 1 and 2 have to be compared with the habits A, B, and n which are under discussion. Therefore the great circles of the poles A, B, and n are plotted in Figs. 3, 4, and 5 together with a 3-deg scatter region for poles A, B and a 6-deg scatter region for pole n. Comparing Figs. 1 and 2 with Figs. 3, 4, and 5 one finds the statements which

Jan 1, 1969

By Donald W. Scott, Nathaniel Arbiter, A. C. Richardson

This paper describes the application of amine flotation to a specific problem—that of increasing the grade of magnetite concentrates derived from an iron ore requiring extremely fine grinding for mineral liberation. Experiments conducted on an iron ore from Wisconsin had shown that concentrates containing 60 to 62 per cent iron and 12 to 14 per cent silica could be produced by magnetic separation. The residual silica occurred as quartz and hornblende, either entrained or locked with magnetite. Most advantageous utilization of the concentrate, however, necessitated that the silica content be reduced to about 5 per cent, equivalent to an iron content of 67.5 per cent. It had been demonstrated that tabling of the magnetic concentrate removed sufficient quartz and hornblende to yield an acceptable concentrate, but disadvantages inherent in tabling dictated that flotation be investigated as a substitute. The goals set for the flotation investigation were: (I) the production of concentrates of about 68 per cent iron content from the magnetic concentrate; (2) an iron recovery of about 85 per cent of that in the feed to flotation; and (3) minimum reagent cost. Both batch and continuous flotation tests were employed; the former, to establish the procedure and the latter to verify it. Although the data were obtained on a specific ore, and with a commercial application in view, it is believed that they have a bearing on other problems where amine flotation is being used or is anticipated. Samples Two samples, designated "(minus 100-mesh magnetic concentrate" and "minus 150-mesh magnetic concentrate," were used for the batch experimental work. They differed only in the degree to which the crude ore was ground prior to magnetic separation. They were stored moist in steel drums in quantities sufficient for all the experimental work reported. This procedure had the advantage of allowing all tests to be made on common samples, but had the disadvantage that the individual flotation samples, because of the difference in storage time, were subject to various stages of surface alteration. Previous work had indicated that common samples were desirable for the batch studies, and it was decided that if these data appeared sufficiently promising the effect of surface alteration could be checked best by continuous tests. The size distributions and the assays of the samples are given in Table I. The minus 150-mesh magnetic concentrate, on which most of the flotation tests were made, assayed 60.9 per cent iron, 13.3 per cent silica, and 0.016 per cent phosphorus. The minus 325-mesh portion represented 78.I per cent of the sample by weight, and assayed 67.9 per cent iron. Thus, the insoluble, mainly silica, was concentrated

Jan 1, 1947

By Donald W. Scott, Nathaniel Arbiter, A. C. Richardson

This paper describes the application of amine flotation to a specific problem—that of increasing the grade of magnetite concentrates derived from an iron ore requiring extremely fine grinding for mineral liberation. Experiments conducted on an iron ore from Wisconsin had shown that concentrates containing 60 to 62 per cent iron and 12 to 14 per cent silica could be produced by magnetic separation. The residual silica occurred as quartz and hornblende, either entrained or locked with magnetite. Most advantageous utilization of the concentrate, however, necessitated that the silica content be reduced to about 5 per cent, equivalent to an iron content of 67.5 per cent. It had been demonstrated that tabling of the magnetic concentrate removed sufficient quartz and hornblende to yield an acceptable concentrate, but disadvantages inherent in tabling dictated that flotation be investigated as a substitute. The goals set for the flotation investigation were: (I) the production of concentrates of about 68 per cent iron content from the magnetic concentrate; (2) an iron recovery of about 85 per cent of that in the feed to flotation; and (3) minimum reagent cost. Both batch and continuous flotation tests were employed; the former, to establish the procedure and the latter to verify it. Although the data were obtained on a specific ore, and with a commercial application in view, it is believed that they have a bearing on other problems where amine flotation is being used or is anticipated. Samples Two samples, designated "(minus 100-mesh magnetic concentrate" and "minus 150-mesh magnetic concentrate," were used for the batch experimental work. They differed only in the degree to which the crude ore was ground prior to magnetic separation. They were stored moist in steel drums in quantities sufficient for all the experimental work reported. This procedure had the advantage of allowing all tests to be made on common samples, but had the disadvantage that the individual flotation samples, because of the difference in storage time, were subject to various stages of surface alteration. Previous work had indicated that common samples were desirable for the batch studies, and it was decided that if these data appeared sufficiently promising the effect of surface alteration could be checked best by continuous tests. The size distributions and the assays of the samples are given in Table I. The minus 150-mesh magnetic concentrate, on which most of the flotation tests were made, assayed 60.9 per cent iron, 13.3 per cent silica, and 0.016 per cent phosphorus. The minus 325-mesh portion represented 78.I per cent of the sample by weight, and assayed 67.9 per cent iron. Thus, the insoluble, mainly silica, was concentrated

Jan 1, 1947

By C. W. Washburne

Recently, Messrs, Mills and Wells1 published a thorough chemical study of the waters associated with oil in parts of the Pennsylvania, Ohio, and West Virginia region. Many of their conclusions are of general application and the writer wishes to discuss some of these. Messrs. Mills and Wells show that the composition of the deep brines oi the Appalachian fields is such as would be produced by the evaporation of sea water and the precipitation of sodium chloride, combined with reactions with hydrocarbons and other substances. The brines are altered, also, by considerable mixing with meteoric water. They give good reasons for believing that the concentration of the brines was produced by evaporation in the rock pores induced by migrating gas, much of which probably escaped to the surface of the ground. This hypothesis was considered by the writer in a former paperJ2 in which main stress was laid on a second hypothesis, that the excess of chlorine in the deep brines may have been due to the entrance of solutions rich in magnesium and calcium chloride which ascended from a deep, possibly intratellurie, source. Messrs. Mills and Wells present good arguments for the first hypothesis. Underground evaporation by ascending gases probably will be accepted as the best available explanation of the concentration and composition of deep well waters. They have not considered the possibility that salt waters in deep sands may be concentrated by the diffusion of water vapor through gas into shale. The writer has given reasons3 for believing that capillary forces concentrate gas and oil in the larger openings of rock, such as the pores of sandstones embedded in shale. The gas underground must be nearly saturated with water vapor at all times, because it always is in contact with the interstitial water of enclosing shales and of the sandstone. Experimental studies of soil moisture have shown that approxi-

Jan 1, 1921

Jan 1, 1923

Jan 1, 1923

By Y. C. Liu, W. R. Hibbard

An aluminum single crystal cold-rolled from (110) [1121 essentially retains its initial orientation after 99.6 pct reduction in thickness. The orientation of the recrys-tallized grains of this material can be described in terms of crystallographic rotations about principal poles of deformation texture. DURING the study of the recrystallization of a copper single crystal cold-rolled from a (110) [112] initial orientation, the orientation of the re-crystallized grains could be derived by a 30" rotation of the orientation of the cold-rolled matrix about its <111> poles.&apos; The present investigation was undertaken to extend the work done on copper&apos; to an aluminum crystal also cold-rolled from a (110) [112] initial orientation. Experimental Procedure The procedure of this experiment was similar to that reported for copper.&apos; An aluminum (99.998 pct) single crystal rod* 1 % in. in diameter was grown in back-reflection technique.&apos; The specimen (1.20x 1.004x0.6787 in. thick) was then rolled along the [112] direction. The final thickness was 0.0028 in., giving a reduction in thickness of about 99.6 pet. Specimens were cut from the rolled strip with scissors, and approximately in. of disturbed metal was removed with Tucker&apos;s reagent. The rolling edge remained intact. The specimens were sandwiched between two graphite plates and annealed in a lead or lead alloy bath which was electrically heated. Pole figures were constructed using the techniques previously described.&apos; Specimens were electrolytically polished4 and etched with 47 pct HNO8, 50 pct HC1, and 3 pct of 48 pct HF. The electrolytic polishing method and etching reagent employed for aluminum specimens were not entirely satisfactory and the microstruc-tures could not be studied in any detail. Results and Discussion The octahedral pole figure of cold-rolled aluminum strip is plotted in Fig. 1. The <111> poles spread in the transverse direction approximately 8" for the highest intensity areas. The spread in the transverse direction can be related to a rotation about two <110> directions lying in a plane containing the rolling direction and rolling plane normal. The two <110> directions and a scale of rotation for the <111> poles are shown in Fig. 2. The amount of rotation is consistent for three of the four <111> poles, about 35" to 40". The discrepancy for the fourth pole is believed to be due to limitations of the film technique. Alternate inter-

Jan 1, 1956

ASIDE from the John Fritz Medal, in which the Institute participates through its representation on the John Fritz Medal Board, the Institute itself has four awards it may make annually, as follows : the Robert W. Hunt Medal and Prize, the J. E. Johnson, Jr., Award, the James Douglas Medal, and the William Lawrence Saunders Medal. ROBERT W. HUNT MEDAL AND PRIZE The partners of Robert W. Hunt established a fund which was presented to the Institute at a fitting ceremony on May 27, 1920, to establish an annual medal and a sum of money to be awarded under the following rules 1. The award shall consist of two prizes: first of a gold medal, second of a sum of money; a certificate to accompany each prize, The money prize shall not be awarded to a member over 40 years of age, but under unusual circumstances, both prizes may be allotted to one person provided that he is not over 40 years of age. In general it will be understood that the Committee shall award the money prize to the younger men, rather than the medal. 2. The awards shall be made not oftener than once a year to that person or persons contributing to the Institute the best original paper or papers on iron and steel. The scope of the term "iron and steel" shall be determined by the sub-committee considering the awards. In general, papers dealing with the practical side of the subject have preference over those dealing with the theoretical side in recognition of the fact that Captain Hunt&apos;s main contributions to the industry have been in the improvement of production and quality of material. 3. A sub-committee of three to five, including the Chairman of the Iron and Steel Committee, shall be appointed by the Iron and Steel Committee annually to adjudge the award subject to approval. 4, The awarding committee shall submit its report to the Iron and Steel Committee at its October meeting, and the award shall be certified to the Secretary of the Institute in time to permit the presentation to be made at the Annual Meeting of the Institute, 5. The recipient of the award shall be designated "The Hunt Medallist," This prize is administered by the Iron and Steel Committee. Awards of the medal have been made as follows 1920-Robert Woolston Hunt. 1926-Charles Lewis Kinney, Jr. J. E. JOHNSON, JR., AWARD This award is made from the income of a fund of $3000 donated by Mrs. Margaret Hilles Johnson in memory of her husband, J. E. Johnson, Jr., who was a prominent engineer, author of two valuable volumes on iron blast-furnace construction and practice, vice-

Jan 1, 1928

ASIDE from the John ,Fritz Medal, in which the Institute participates through its representation on the John Fritz Medal Board, the Institute itself has four awards it may make annually, as follows : the Robert W. Hunt Medal and Prize, the J. E. Johnson, Jr., Award, the James Douglas Medal, and the William Lawrence Saunders Medal. ROBERT W. HUNT MEDAL AND PRIZE The partners of Robert W. Hunt established a fund which was presented to the Institute at a fitting ceremony on May 27, 1920, to establish an annual medal and a sum of money to be awarded under the following rules: 1. The award shall consist of two prizes: first of a gold medal, second of a sum of money; a certificate to accompany each prize. The money prize shall not be awarded to a member over 40 years of age, but under unusual circum- stances, both prizes may be allotted to one person provided that he is not over 10 years of age. In general it will be understood that the Committee shall award the money prize to the younger men, rather than the medal. 2. The awards shall be made not oftener than once a year to that person or persons contributing to the Institute the best original paper or papers on iron and steel. The scope of the term "iron and steel" shall be determined by the sub-committee considering the awards. In general, papers dealing with the practical side of the subject have preference over those dealing with the theoretical side in recognition of the fact that Captain Hunt&apos;s main&apos; contributions to the industry have been in the improvement of production and quality of material. 3. A sub-committee of three to five, including the Chairman of the Iron and Steel Committee, shall be appointed by the Iron and Steel Committee annually to adjudge the award subject to approval. 4. The awarding committee shall submit its report to the Iron and Steel Committee at its October meeting, and the award shall be certified to the Secretary of the Institute in time to permit the presentation to be made at the Annual Meeting of the Institute. 5. The recipient of the award shall be designated "The Hunt Medallist." This prize is administered by the Iron and Steel Committee. Awards of the medal have been made as follows: 1920-Robert Woolston Hunt. 1926-Charles Lewis Kinney, Jr. J. E. JOHNSON, JR., AWARD This award is made from the income of a fund of $3000 donated by Mrs. Margaret Hilles Johnson in memory of her husband, J. E. Johnson, Jr., who was a prominent engineer, author of two valuable volumes on iron blast-furnace construction and practice, vice-

Jan 1, 1928

By John E. Young

U.S. Steel Corp.&apos;s Winifrede mine is operated by Lynch District in the mountainous region of eastern Kentucky. This region is characterized by narrow finger ridges and precipitous slopes, which present both an opportunity and challenge in the design and selection of coal-handling facilities for the movement of coal from the section belts to the railrod cars. Lynch District selected diesel-powered locomo¬tives and 100-ton articulated cars capable of negotiating sharp curves. The drop¬bottom mine cars are equipped with longitudinally hinged doors that are auto¬matically opened and closed. Lynch District selected a large-diameter steel-lined borehole for lowering the coal approximately 1000 ft from the seam level to the valley floor railroad load-out point. Taking advantage of gravity, the presized coal is "lowered" vertically approximately 720 ft to existing entries of a previously abandoned mine. The coal is then conveyed horizontally into storage. The coal¬handling facility from the mine-car dump to the railroad load-out point is fully automatic through use of tone control. TV cameras are installed along the facility to continuously monitor the strategic points. The diesel locomotives are either directly operated or remotely radio-controlled, depending on the functions Per¬formed. U.S. Steel Corp.&apos;s Winifrede mine is operated by Lynch District in the mountainous region of eastern Kentucky. This region is characterized by narrow mountain ridges and precipitous slopes which present both an opportunity and challenge in the design and selection of coal-handling facilities for the movement of coal from the section belts to the railroad cars. The narrow finger ridges precluded use of under¬ground haulage and, thereby, presented the opportunity to use high-capacity equipment on the outside bench. The precipitous mountain slopes, steepest at the Wini¬frede seam horizon, presented a challenge to select a solution for lowering the coal approximately 1000 ft from the seam level to the valley floor railroad load-out point. It was evident from the start of planning that these two factors predominated; namely, rail haulage and coal lowering, and solutions to these would determine the final design of the Winifrede mine coal-handling facilities. The Winifrede mine derives its name from the Wini¬frede Seam which comprises the total reserve recov¬erable from this facility. The seam is 5 ft high with a good siltstone bottom and competent shale or sandstone roof. The seam is at an elevation of 2700 ft where the mountain ridges are long and narrow. This configuration of the reserve was ideal for conveyor belt installation to transport the coal from the working face to the outside bench. The preclusion of underground rail haul¬age permitted an opportunity to review the type of locomotive power and to select high-capacity equipment without the limitations associated with underground systems. Since the basic electrical design of the mine was al¬ternating current, with rectification to direct current for shuttle cars required only in the face areas, there was no point in bearing the burden of additional cost of dc trolley installation. And, since the haulage would re¬quire only a few tunnels to negotiate sharp points and to reach the back side of the reserves, diesel power was selected for the haulage locomotives. To provide stability on the almost continuously curv¬ing track and to provide the maximum width of haul¬age equipment, both locomotives and mine cars, stan¬dard railroad gage was chosen to offer the largest choice of equipment. The decision was made to select a standard 45-ton railroad diesel locomotive but to lower the cab height to reduce tunnel excavation requirements. The mine car was the next challenge. Past experience in Lynch operations indicated that drop-bottom cars would be a successful application with the free-flowing coal. The search was for a drop-bottom car within the dimensions of the locomotive to discharge the coal in the shortest time. Numerous types were considered and visits made to various sites to observe cars in operation.

Jan 1, 1972

By S. L. Payne, J. P. Morris, R. L. Kipp, G. R. Zellars

The activities of iron and nickel in liquid Fe-Ni alloys were determined by measuring the vapor pressures of iron and nickel above the alloys and comparing with the vapor pressures of the pure metals. Nickel was found to deviate negatively from Raoult&apos;s law over the entire composition range. Iron behaves ideally down to 0.7 mole fraction but shows negative deviations at lower concentrations. At 1600°C the activity coefficients at infinite dilution are 0.40 for iron and 0.66 for nickel. 1 HE formulation of the conditions of chemical equilibrium between liquid metals and gases or slags is an important application of thermodynamics to pro- cess metallurgy. Usually the metal and slag phases are solutions of several components; and for accurate calculations, it is often necessary to use the activities of the components in place of their concentrations. Data concerning activities, however, are quite meager. The evaluation of the activities of iron and nickel, presented in this paper, is part of a project to determine activities in iron alloys at elevated temperatures.

Jan 1, 1960

By Peter R. Drummond

THE final casting of refined copper has been re-J- stricted for generations by the following sequence of operations: Filling the reverberatory furnace, melting, skimming, blowing or flapping, and poling. The hoped-for 24 hr cycle, producing 300 tons or more, has been taken up largely with the necessary bat time-consuming tasks of cleaning the bath, sulphur elimination, and in turn removal of excess oxygen to produce tough-pitch copper. Incidental to comparatively slow melting under combustion gases, copper oxides react with the furnace lining, and the slag so-formed must be completely recycled. The three-phase arc furnace has eliminated some of the cycle stages, and telescoped the remainder into a continuous operation. Electrical energy, supplied to graphite electrodes enclosed in high grade refractories, rapidly melts copper cathodes and sustains a stream of metal, containing approximately 0.01 pct oxygen, without contamination from fuel. The arc was struck on the first large electric furnace for melting copper in the United States on April 13, 1949. The earliest use of this type of furnace was at Copper Cliff, Ont., in 1936, and an admirable description of their installation has been published? Copper, melted in the Baltimore furnace, is used to cast billets, and the installation differs somewhat from the Canadian, as will be described. The arc furnace is a heavy-duty, three-phase furnace, holding 50 tons, the general outline of which appears on Fig. 1. The steel shell is 15 ft ID with a bottom radius of 14 ft 2 in. The roof, separate and distinct from the body, consists of a 15-ft water-cooled, cast-steel ring of the same outside diameter as the furnace. The center line of the furnace lies 9 ft 6 in. from that of the trunnions, permitting a 5" backward tilt for skimming, and a 40" maximum nose tilt forward for complete draining. Normally, the furnace overflows by displacement, and the use of the forward tilt arrangement is restricted to covering charging delays. The charging slot, 3 ft 8 in. x 5 in., lies on the north center line, the tap hole on the south, and the 30x30 in. skim door 45" to the west of the slot. The original 20-in. graphite electrodes were replaced with 14 in. in December 1949. Three conventional direct current winch drives, governed by electrical controls, position each electrode which has individual mast supports and counterweights. An independent circulation supplies cooling water for the electrode glands, the roof ring, charge slot, and the skim door frame. Arc Furnace Refractories Hearth: Fused-in monolithic bottoms had been used in copper arc furnaces, installed prior to April 1949. These consisted of thin layers of periclase, successively fused in place over preliminary brick courses. Heat was obtained from the arc, using a T-like arrangement of broken electrodes resting directly on the periclase to be fused. The operation, taking weeks to perform, was very expensive. The chemically-bonded magnesite-brick bottom, installed at Baltimore, was the first of its kind and a radical departure from previous practice. It consists of a 1 to 6-in. layer of castable refractory laid on the steel shell, modifying it to a 12 ft 2 in. bottom radius. Two courses of 9x2 % -in. fireclay straights and keys follow. The third course is made of 9-in. magnesite blocks of special shape to form circles of an inverted arch. It was started by a four piece keystone with skew-backs forming the outer course. The fourth course also started on a central keystone, or button, of four 90" segments, 12 in. diam x 13 Vz in. deep, and continued with 13%-in. blocks. Skewbacks at the shell completed the course to produce a horizontal surface for the side walls with a single course of No. 2 arch fireclay against the steel. Dry chrome-magnesite cement was brushed over each course after laying, and a 1-in. expansion space between the brick and the shell was filled with the same mixture. The total bottom thickness, excluding the castable material, was 5 in. of clay plus 22% in. of chemically-bonded magnesite. Tap Hole: A 5-in. OD and 3-in. ID silicon-carbide tube constitutes the tap hole and is set tangential to the upper course of the furnace bottom. Molten metal fills the tube when the furnace is level and filled to capacity. Side Walls: The lining, against the shell, consists of a 9x4Y2x3 in. soldier course of fireclay, using straights and No. 1 arches to turn the circles. A second soldier course of 9x4&apos;/2x2&apos;/2-in. fireclay was laid in a somewhat similar fashion. Three courses of 13Y2x6x3 in. and 9x6~3 in. of final magnesite, laid flat, completed the lining, using Nos. 1 and 2 keys to turn the circles. Cardboard spacers were placed between every two bricks in horizontal courses, and a thin coat of chrome-magnesite cement filled the joints between the firebrick and magnesite. A sprung-arch spanned the skim door with jambs of suitable magnesite shapes. Charge Slot: The slot is 3 ft 8 in. wide x 5 in. high. A silicon-carbide sill of special shapes has a 30" slope to allow cathodes to slide easily into the bath. The original arch was flat, and composed of Nos. 1 and 2 wedge magnesite with a 6-ft radius. It projected 5 in. over the sill, and, being a flat arch, gave an 18 15/16-in. opening between the inner edge and the metal line. The whole assembly was later raised 9 in., and the flat arch replaced with an arch, the lower edge of which maintained the 5-in, width from the outer to inner edges as shown in Fig. 2. A water-cooled, cast-copper jacket protects the steel shell behind the slot.

Jan 1, 1952

By Walter Harvey Weed

THE enrichment of mineral-veins as a result of the migration of material from an upper oxidized or disintegrated part of a vein to a lower level, where it is redeposited, is now, I believe, quite generally accepted as one explanation of the occurrence of bonanzas in gold- and silver-veins, as well as that of bodies of high-grade ores in cupriferous deposits.* Vogt has called attention to the fact that there are numerous examples of such rich shoots which are " of exclusively primary character, and dependent upon the laws which governed the original ore-deposition." To this I would add that there are also other examples which are neither of primary origin nor clue to descending waters, but result from a reopening of the veins and their penetration by ascending heated waters whose metallic contents are deposited by reaction with the primary pyrite (and possibly other minerals), forming "secondary" enrichments. My studies of the copper-veins of Butte, Montana, show: That the veins there are of several ages and systems; that the older primary quartz-pyrite veins were reopened by later movements, correlated with a period of volcanic activity; and that they were penetrated by hot alkaline waters carrying copper and arsenic in solution, which were deposited presumably by reaction with the pyrite of the original vein. The enormous development of the Butte deposits, attendant upon the extraction of nearly 10,000 tons of ore a day, has revealed many facts concerning the nature and distribution of the ores. Enargite, the copper sulpharsenate, formerly a relatively rare mineral, is now found to be the chief ore of some veins,

Jan 1, 1913

By A. J. Williams

THE province of Saskatchewan, situated in the center of the Great Plains region of Canada, has, like most prairie areas, an essentially agricultural economy. Most of its population of about 860,000 is located in the southern half of the province in the farming and ranching areas. To the north of the prairie is a broad forested belt supporting a considerable timbering industry, and the northern one third of the province is glaciated pre-Cambrian rock formation. This latter area is relatively barren of vegetation, but the presence within it of a considerable variety of radioactive, noble and base metals, and industrial minerals has been shown by prospecting in recent years.&apos; Glacial Geology The Keewatin ice sheet, considered to have accumulated in the country to the west of Hudson Bay in Pleistocene time, covered at its maximum advancement almost all of Saskatchewan and extended south of the international boundary. Only in the Cypress Hills in the southwest and around Wood Mountain in the south central portion of the province did the preglacial formations escape the action for this glacial period. The bedrock of the plains and forest areas therefore is overlain by moraines and modified glacial drift, which vary in thickness from a few feet to 400 or 500 ft.&apos; Glacial action in the pre-Cambrian area of the province was largely erosional, most of the more recent formations and some of the pre-Cambrian rock being transported out of the area to the south and west. It has been estimated that about 13 pct of this area is composed of lakes and rivers not too adaptable to rail or water transportation, so that until the use of aviation for exploration purposes became general, development of the area was slow. To the south, the heavy mantle of glacial drift has to some extent deterred the discovery of industrial minerals in the bedrock underlying the forest and prairie regions3 At the same time, this drift contains numerous deposits of those most elementary and necessary industrial minerals, sand and gravel. Sedimentary Basin The major feature of the sedimentary deposits underlying the plains regions is the basinal structure known as the Moose Jaw syncline, which runs from the southeast corner of the province in a northwesterly direction. To the west of this syncline the formations curve upward, then have been faulted and further upthrust to appear at the surface in the foothills of the Rockies in Alberta; to the east and north they curve upward into Manitoba and northern Saskatchewan, but the surface contacts are covered mostly with glacial drift.238 The axis of the syncline dips to the southeast, so that there is also an upward trend of the formations along the axis to the northwest. In illustration of the regional structure underlying the province, the pre-Cambrian basement has been logged in drillholes at the following depths in several locations: Ogema (south central), 9390 ft; Gronlid (northeast), 2599 ft; Vera (northwest), 4422 ft; Big River (north northwest), 2348 ft. Fig. 1 indicates the general surface geology of the province, ignoring such glacial overburden as may overlie many of the bedrock formations. Also indicated is the approximate location of the axis of the Moose Jaw syncline.&apos; Industrial Minerals Clays: The province is fortunate in possessing a widespread distribution of clays of ceramic value, ranging from those used for heavy structural products to the high grade pottery and china clays. Shales suitable for brick and tile production are found in the Upper Cretaceous and Tertiary formations across the south of the province where the glacial drift is thin or nonexistent. Many deposits of glacial lake clays suitable for such wares are found scattered over the rest of the province south of the pre-Cambrian area. The Whitemud formation of the Upper Cretaceous is a narrow sedimentary band of secondary clays found intermittently at points across the south of the province where glacial action did not disturb or remove them.&apos; In the southwest corner of the province, around Eastend in the Frenchman River valley, the refractory clays of this formation are contaminated somewhat with iron compounds or other alteration products of basaltic rocks. This eliminates the use of those clays in true whitewares, as they fire to creamy buff shades at the lower temperatures and to a blue-specked grey at cone 8 to 12, (2280°F to 2390°F), the range commonly used in firing whiteware. However, for use in the production of colored artware, caneware, stoneware or crockery, and sewerpipe, this type of clay makes an excellent body that requires little or no addition of flint, feldspar, or other fluxing materials such as are required in the higher class of ware.&apos; It is not a grade of clay that can be shipped great distances to the manufacturing centers, but a market for considerable tonnages has developed at nearby Medicine Hat, where cheap natural gas is available for the firing of the ware. Farther east in the south central portion of the province, the clays of the Whitemud formation are generally more refractory and white burning. The formation is divided into three zones, consisting of white clays, brown shale, and white sandy clays.

Jan 1, 1953

By A. J. Williams

THE province of Saskatchewan, situated in the center of the Great Plains region of Canada, has, like most prairie areas, an essentially agricultural economy. Most of its population of about 860,000 is located in the southern half of the province in the farming and ranching areas. To the north of the prairie is a broad forested belt supporting a considerable timbering industry, and the northern one third of the province is glaciated pre-Cambrian rock formation. This latter area is, relatively barren of vegetation, but the presence within it of a considerable variety of radioactive, noble and base metals, and industrial minerals has been shown by prospecting in recent years.1 Glacial Geology The Keewatin ice sheet, considered to have accumulated in the country to the west of Hudson Bay in Pleistocene time, covered at its maximum advancement almost all of Saskatchewan and extended south of the international boundary. Only in the Cypress Hills in the southwest and around Wood Mountain in the south central portion of the province did the preglacial formations escape the action for this glacial period. The bedrock of the plains and forest areas therefore is overlain by moraines and modified glacial drift, which vary in thickness from a few feet to 400 or 500 ft.2 Glacial action in the pre-Cambrian area of the province was largely erosional, most of the more recent formations and some of the pre-Cambrian rock being transported out of the area to the south and west. It has been estimated that about 13 pct of this area is composed of lakes and rivers not too adaptable to rail or water transportation, so that until the use of aviation for exploration purposes became general; development of the area was slow. To the south, the heavy. mantle of glacial drift has to some extent deterred the discovery of industrial minerals in the bedrock underlying the forest and prairie regions.3 At the same time, this drift contains numerous deposits of those most elementary and necessary industrial minerals, sand and gravel. Sedimentary Basin The major feature of the sedimentary deposits underlying the plains regions is the basinal structure known as the Moose Jaw syncline, which runs from the southeast corner of the province in a northwesterly direction. To the west. of this syncline the formations curve upward, then have been faulted and further upthrust to appear at the surface in the foothills of-the Rockies in Alberta; to the east and north they curve upward into Manitoba and northern Saskatchewan, but the surface contacts are covered mostly with glacial drift.2,3 The axis of the syncline dips to thee southeast, so that there is also an upward trend of the formations along the axis to the northwest. In illustration of the regional structure underlying the province, the pre-Cambrian basement has been logged in drillholes at the following depths in several locations: Ogema (south central), 9390 ft; Gronlid (northeast), 2599 ft; Vera (northwest), 4422 ft; Big River (north northwest), 2348 ft. Fig. 1 indicates the general surface geology of the province, ignoring such glacial overburden as may overlie many of the bedrock formations. Also indicated is the approximate location of the axis of the Moose Jaw syncline.4 Industrial Minerals Clays: The province is fortunate in possessing a widespread distribution of clays of ceramic value, ranging from those used for heavy structural products to the high grade pottery and china clays. Shales suitable for brick and tile production are found in the Upper Cretaceous and Tertiary formations across the south of the province where the glacial drift is thin or nonexistent. Many deposits of glacial lake clays suitable for such wares are found scattered over the rest of the province south of the pre-Cambrian area. The Whitemud formation of the Upper Cretaceous is a narrow sedimentary, band of secondary clays found intermittently, at points, across the, south of the province where glacial action did not disturb or remove them.8 In the southwest corner of the province, around Eastend in the Frenchman River valley, the refractory clays of this formation are contaminated somewhat with iron compounds or other alteration products of basaltic rocks. This eliminates the use of those clays in true whitewares, as they fire to creamy buff shades at the lower temperatures and to a blue-specked grey at cone 8 to 12, (2280°F to. 2390°F), the range commonly used in firing whiteware. However, for use in the production of colored artware, caneware, stoneware or crockery, and sewerpipe, this type of clay makes an excellent body that requires little or no addition of flint, feldspar, or other fluxing materials such as are required in the higher class of ware.9 It is not a grade of clay that can be shipped great distances to the manufacturing centers, but a market for considerable tonnages has developed at nearby Medicine Hat, where cheap natural gas is available for the firing of the ware. Farther east in the south central portion of the province, the clays of the Whitemud formation are generally more refractory and white burning. The formation is divided into three zones, consisting of white clays, brown shale, and white sandy clays.

Jan 1, 1952

By Donald W. Scott, Nathaniel Arbiter, A. C. Richardson

THIS paper describes the application of amine flotation to a specific problem-that of increasing the grade of magnetite concentrates derived from an iron ore requiring extremely fine grinding for mineral liberation. Experiments conducted on an iron ore from Wisconsin had shown that concentrates containing 60 to 62 per cent iron and 12 to 14 per cent silica could be produced by magnetic separation. The residual silica occurred as quartz and hornblende, either entrained or locked with magnetite. Most advantageous utilization of the concentrate, however, necessitated that the silica content be reduced to about 5 per cent, equivalent to an iron content of 67.5 per cent. It had been demonstrated that tabling of the magnetic concentrate removed sufficient quartz and hornblende to yield an acceptable concentrate, but disadvantages inherent in tabling dictated that flotation be investigated as a substitute. The goals set for the flotation investigation were: (I) the production of concentrates of about 68 per cent iron content from the magnetic concentrate; (2) an iron recovery of about 85 per cent of that in the feed to flotation; and (3) minimum reagent cost. Both batch and continuous flotation tests were employed; the former, to establish the procedure and the latter to verify it. Although the data were obtained on a specific ore, and with a commercial application in view, it is believed that they have a bearing on other problems where amine flotation is being used or is anticipated. SAMPLES Two samples, designated "minus 100mesh magnetic concentrate" and "minus 150-mesh magnetic concentrate," were used for the batch experimental work. They differed only in the degree to which the crude ore was ground prior to magnetic separation. They were stored moist in steel drums in quantities sufficient for all the experimental work reported. This procedure had the advantage of allowing all tests to be made on common samples, but had the disadvantage that the individual flotation samples, because of the difference in storage time, were subject to various stages of surface alteration. Previous work had indicated that common samples were desirable for the batch studies, and it was decided that if these data appeared sufficiently promising the effect of surface alteration could be checked best by continuous tests. The size distributions and the assays of the samples are given in Table I. The minus 150-mesh magnetic concentrate, on which most of the flotation tests were made, assayed 60.9 per cent iron, 13.3 per cent silica, and 0.016 per cent phosphorus. The minus 325-mesh portion represented 78.1 per cent of the sample by weight, and assayed 67.9 per cent iron. Thus, the insoluble, mainly silica, was concentrated

Jan 1, 1945

By E. S. Machlin, C. W. Chen

THIS investigation is concerned with the origin of the intercrystalline voids and cracks formed in metals and alloys subjected to stress at elevated temperature. There have been many suggestions in the recent literature relating to this problem. Greenwood&apos; suggested that the voids may be produced by vacancy condensation. Zener has stated that shear-stress relaxation across grain boundaries could initiate high tensile stresses at the regions blocking grain boundary slip and thereby cause the formation of cracks. Chang and Grant3 have described the formation of cracks at grain boundary triple points and have experimentally verified Zener&apos;s mechanism for the grain boundary regions in the vicinity of a triple point. Subsequent to the completion of this investigation, Gifkins4 developed a model which made use of Stroh&apos;s5 mechanism of fracturing to produce sub-microscopic fractures that subsequently grow by grain boundary slip. Chen and Machlin,6 in answer to Gifkins, described a model deduced from the present investigation, in which grain boundary slip provides both the stress to fracture at grain boundary jogs and the deformation required to separate fractured jog surfaces. The possibility of gas condensation to form intercrystalline voids and cracks is eliminated as a basic mechanism because such voids and cracks are developed in vacuum melted material containing minute amounts, if any, of gaseous impurities. In a theoretical evaluation of this problem, Machlin7 concluded that void nucleation by vacancy condensation during creep-rupture is improbable but that vacancy condensation on supercritical sized voids to produce growth is probable. This investigation was begun to evaluate the suggested mechanisms for intercrystalline fracture. In particular, in order to correlate vacancy supersaturation ratios produced in creep with those determined by Bal-luffi and Seigle8 as critical for , the nucleation of voids, specimens were obtained from the same heat of brass as used by the latter authors, through the courtesy of Dr. Seigle. The experiments conducted in this investigation fall into the following categories: 1) Brass—observation of voids produced under a variety of conditions, including creep under compression, to evaluate the mechanisms of void nucleation and growth. 2) Bicrystal experiments to check the mechanism of void nucleation deduced in this investigation. 3) Morphology of intercrystalline voids produced in a variety of metals. Each set of experiments will be described and discussed separately. Experimental Techniques A special creep-rupture test rack was constructed which made it possible to apply the stress to the specimen in a controlled atmosphere of inert gas, reducing gas, or vacuum. All the creep-rupture tests on a-brass (30 pct Zn) were conducted in nitrogen under a pressure slightly above atmospheric. Either dead weight loading or constant elongation rate loading could be applied with the load measured by means of a strain gage dynamometer. In order to obtain a coarse-grained crystal structure stable at

Jan 1, 1958