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By David R. Poirier

Activity data of carbon as a function of both temperature and composition throughout the stable austenite range is correlated by mearts of an equation derived from a quasi-chemical model. The carbon activity data of austmite for temperatures between 800° and 1200°C are utilized in conjunction with the activity of carbon calculated for the y solidus using the activity of carbon in liquid iron and published austenite-liquid equilibria. The results agree very well with Chip-man's correlation; however, a small difference in the activity of carbon in the high-temperature range of the austenite field is evident. Excellent agreement is found for the heat of solution of graphite in infinitely dilute austenite; from this study the value is 10,550 cal as compared with Chipman's value of 10,680 cal. AS part of a program to study microsegregation in dendritic solidification of ternary Fe-C-Cr alloys, it was desirable to be able to describe the equilibria between austenite and liquid iron in Fe-C-Cr alloys. In this regard, it was necessary to correlate existing data on the activity of carbon in Fe-C austenite as a function of both temperature and composition. At that time, Chipman's analysis1 of the thermodynamics of binary Fe-C austenite was not available. It will be shown that this study and Chipman's study agree rather well throughout the stable austenite range of temperature and composition; however, some small differences appear at temperatures greater than the eutectic temperature. Benz and Elliott 2 presented isoactivity lines for austenite superimposed on their revised Fe-C phase diagram. Using an expression from Darken and Gury 3 representing Smith's4 activity data between 800" and 1000°C, they found that the activities extrapolated above 1000°C to the solidus did not agree with the activities determined from the corresponding liquidus compositions. It is the purpose of the following argument to reconcile carbon activity data of austenite with the activity in liquid Fe-C alloys as determined by Rist and Chipman. 5 In addition, a simple analytical expression is sought for computational convenience. ACTIVITY DATA OF CARBON IN ZRON Fig. 1 shows the activity of carbon in Fe-C austenite as determined by Smith, 4 Schenck and Kaiser, 6 Scheil et a1.,7 and Bungardt et al.' The lines are merely drawn to separate the data into the respective isotherms. These data are inadequate to determine the activity of carbon at temperatures greater than 1200°C. The activity coefficient in Fe-C liquid alloys was assumed by Rist and chipmans to obey the following

Jan 1, 1969

By J. N. Hobstetter, J. J. Becker

Deformed copper single crystals exhibited, upon annealing, a recrystallized twinned grain with a twin plane parallel to an active deformation plane, rotated approximately 22" about its pole, or else did not recrystallize at all. If extraneous deformation was not carefully removed, no simple orientation relationship was found. RECRYSTALLIZATION textures have been a subject of practical interest for many years, but any real understanding of their formation will have to start with a study of the recrystallization of carefully deformed single crystals. Some efforts have been made in this direction,'-' but much more experimental information is needed before a satisfactory picture of the crystallography of recrystallization can be formed. This paper reports a few results in copper single crystals. The crystals studied in this investigation were grown by the Bridgman method," and their orientations determined by the back-reflection Laue technique." Some specimens were simply deformed in compression, others were sheared, and still others tested in a rotating-grip device, in attempts to remove end constraints. The details of their deformation behavior are described elsewhere.' The deformed specimens were annealed and the orientations of the recrystallized grains were determined optically, as described by Barrett and Levenson.8 Compressed Specimens Specimen 17-A, whose orientation is given in Fig. 1, was compressed to a total of 19 pct. As observed before,' increasing deformation took place by increasing density of slip lines in initially formed clusters, with little if any formation of new slip clusters in unslipped areas. The specimen was then etched in nitric acid until its length had been reduced from 0.766 to 0.735 in. It was annealed at 1000°C, in increments of a few minutes. After 63 min, two small grains had appeared in the center, Fig. 2. They were found to be twinned with respect to each other (AB, Fig. 4). After 30 min more, the specimen was completely recrystallized. A typical view of it is given in Fig. 3. A summary of all orientations found is given in Fig. 4, in which the prominent grain G is in (001) standard projection, and the poles of the active slip planes after deformation are indicated by SP (primary slip plane), CrSP (cross-slip plane), and CnSP (conjugate slip plane). All the orientations found were related through seven orders of twinning. A "family tree" of these twins is given in Fig. 5. Furthermore, the BG twin composition plane lies close to the cross-slip plane

Jan 1, 1954

By J. H. Mallery, J. H. Keeler

THE crystal structure of Zral, the compound richest in zirconium (91.03 pct Zr by weight) in the system Zr-Al, has been found to be ordered face-centered-cubic. This compound is of particular interest, since it is encountered as the precipitated phase in potentially useful zirconium-rich alloys. It forms peritectoidally from body-centered-cubic zirconium and Zr,Al at about 975°C. The Zr-A1 constitution diagram has been reported by McPherson and Hansen.' For the primary determination a 100 g ingot was prepared by arc-melting in a water-cooled copper crucible under purified argon. The raw materials were crystal-bar zirconium (a purity of better than 99.7 pct) and spectroscopically pure aluminum. The ingot was double melted, examined metallographi-cally, and found to be quite uniform as shown in Fig. 1. The hardness of the as-cast button was VHN 390 to 445. A 20 mil diam specimen was prepared from annealed (900°C) filings of Zr,Al. The specimen was mounted in a 5 cm radius powder camera and an 8 hr exposure was taken using copper radiation with a nickel filter. The structure of the compound Zral was found to be ordered face-centered-cubic of the Cuau type, with an a,, value of 4.37220.003A. Its calculated density is 5.976e0.013 g per cu cm. The relative intensities for the lines were calculated using the formula 1+cos2 20 I oc----------------- • p • /F7 sin2 0 cos 0 1 + COS' 20 where----------------is the Lorentz polarization fac- sin2 0 cos 0 tor, p is the multiplicity factor, and F is the structure factor. The X-ray data are given in Table I. The compound has exhibited plasticity when present as particles in a matrix of a zirconium. During hot working at about 900°C, the compound has been found to deform plastically to the extent that some of the particles exhibit a length-to-width ratio greater than 4:1 as shown in Fig. 2. In answer to the discussion of ref. 1, McPherson and Hansen pointed out that the compound may be cold rolled and reduced as much as 33 pct. Zr,Al has also been found2 under certain conditions to precipitate in lamellar form at grain boundaries of the a phase of hexagonal-close-packed zirconium. Acknowledgment This work was carried out under Contract W-31-109-Eng 52 for the United States Atomic Energy Commission.

Jan 1, 1956

With a mine output as high as 5000 tpd and mill capacity of 7000 tpd, the uranium mining and milling complex owned and operated by Kerr-McGee Nuclear Corp. in the Ambrosia Lake area is the largest in the U.S. and is likely to remain so for some time. Next year, Kerr- McGee expects to have in production another mine in Section 19 of the Ambrosia area-and will begin ore production in 1976 at its new $15-million mine at Church Rock, located northeast of Gallup, N. M., where the company has already completed the shaft work and is in the early stages of project development. Ore from Church Rock will be transported to the company's facilities at Ambrosia Lake for processing. Kerr-McGee's existing eight mines in Ambrosia Lake go to depths of about 800 to 1500 ft to tap the various horizons of uranium-bearing sands in the Westwater Canyon of the Morrison formation.

Jan 8, 1974

By Franklin Allison

THE influence of cobalt and nickel on the properties of steel might be readily expected to be very similar. The two elements occupy close and somewhat unusual positions in the periodic table, their chemical behavior and compounds are so completely analogous and their various physical properties, including the ferro-magnetic characteristic, show such a remarkable correspondence, that there is no doubt of a strong resemblance existing between these two metals. However, the variety of, properties that are obtained from steel is due, largely to the fact that the element iron possesses allotropic forms. Alloying elements that affect these allotropic forms, or alter the nature of the allotropic changes, exert a profound influence on the resulting steel. In the case of nickel and cobalt, although these elements are very similar chemically and physically, it is found that they differ distinctly in their individual effects on the critical points of iron. Both nickel and cobalt form a series of homogeneous solid solutions with iron at temperatures above 1800° F. The difference in their behavior does not occur until changes begin to take place in the solid state below this temperature. An inspection of the respective thermal equilibrium diagrams at the lower temperatures makes the opposite effects of nickel and cobalt clearly evident.

Jan 3, 1927

By Jose J. Alvarez

INTRODUCTION Three major plant processes control the operation of an uranium in-situ mining plant. The three pro- cesses can be categorized under the headings termed - loading, elution, and precipitation. All other plant processes can be subcategorized under the three. In summary, the major plant processes in an in- situ mining plant are: 1. Loading - The pregnant lixiviant from the production wells flows through anion exchange resin. The loading of the uranium on the resin is controlled by various factors, such as ionic strength, valence, functional groups, etc. 2. Elution - The uranium-loaded resin is eluted or regenerated by a high ionic strength solution. The effluent from this process is de- fined as the pregnant eluate. 3 . Precipitation - The pregnant eluate is chemically treated to attain the ideal conditions for the selective precipitation of uranium. Hydrogen peroxide is an ideal precipitating agent under URI conditions. This paper will focus on two of the major processes: Elution and Precipitation. For the most part this relatively young industry has grasped the theory of liquids in continuous flow for the operation of the plant processes. Likewise, URI initially operated the two processes of interest with the continuous flow concept. Through laboratory experiments, URI has abandoned the flow concept and operates the eluting and precipitating stages with the concept of "batch" processes, whereby only one container, filled to a specified liquid level, is chemically processed. In the proceeding sections, each of the two pro- cesses will be discussed in detail, from their original concept to the present operation. Only minor modifications were made to the existing circuits for the conversion with results revealing a greater level of efficiency. ELUTION The elution of the loaded anion exchange resin can be achieved by different high ionic strength solutions. The selection of constituents is dependent on both chemical and economic considerations (i .e., efficiency and operating/restoration factors). The regenerant presently used is a pH 9.5 solution containing 7.5% NaCl and a mixture of Na2C03/NaHC03. expressed as 2.5% NaHC03.

Jan 1, 1980

By H. J. Levinstein, W. H. Robinson

A method of chemically polishing silver for metal-lographic examination has been developed. The samples are prepared by polishing on 0, 2/0, and 3/0 paper. They are then polished on 600 micro-cut paper, followed by a final mechanical polish on a cloth containing 5µ diamond paste. The samples are then chemically polished in a solution of 100 cc of saturated chromic acid and 5 cc of a 5 pct HC1 solution. The chemical polishing is performed by swabbing with a cotton ball saturated with the solution. During the chemical polishing, the sample is rinsed frequently in running water. Polishing in this manner for 5 min is sufficient to remove the strained material from the previous polishing operations. The amount of material removed is approximately 4µ/min. The surface obtained is flat and free of pits. Fig. 1 is an interference micrograph of a silver surface polished by this technique. If the solution employed is of improper HC1 content, an interference color film will form on the sample. This film can be removed either by swabbing with a cotton ball saturated with ortho-

Jan 1, 1962

By C. W. Kovach, A. Moskowitz

Studies were undertaken to investigate the effects of manganese content on the machinability and other Properties of a free machining martensitic stainless steel (AISI Type 416). Machinability was found to be significantly improved in steels of high manganese content, and a direct relationship was obtained between machinability and steel Mn:S ratio. As the manganese content of the steel increases, the sulfide Phase present changes from CrS to (FeMn)Cr2S4 to (MnFeCr)S, and finally to MnS. The average sulfide inclusion hardness decreases through the same range of increasing manganese content. The mechanism for machinability improvement is discussed in terms of a soft ductile sulfide affecting deformation in the secondary shear zone. Type 416 containing relatively high manganese for improved machinability shows good general properties. The effects of increasing manganese content on mechanical properties, cold formability, and corrosion resistance are described. THE addition of sulfur is commonly used to improve the machinability of stainless steels. However, little attention has been paid in the past to the composition and characteristics of the sulfur-containing phase or phases present in these resulfurized steels. Recent information on the properties of sulfide phases, and their role in metal cutting, suggests that variations in these phases could have critical effects on machin-ability, as well as important effects on formability and other properties such as corrosion resistance. Manganese, chromium, and iron are strong sulfide forming elements present in stainless steels! of these, manganese has the greatest sulfide forming tendency and iron the least.1"1 The manganese content of resul-furized 13 pct Cr steels, often about 0.5 pct, can be insufficient or only barely sufficient to combine with the sulfur that is present; thus, the precise level of manganese can strongly influence the nature of the sulfide phase. Sulfide phases which may be present in stainless steels have been reported to include CrS, a spinel-type sulfide, chromium-rich manganese sul-fide, and manganese Sulfide.5,6 Detailed phase relationships for the Fel3Cr-Mn-S system have been reported by the present investigators,7 and a portion of this work will be referred to subsequently in this paper. Recent work by Kiessling6 and Chao et a1.8 has shown that sulfide phases can display wide variations in hardness, and may undergo considerable plastic deformation under isostatic loading.9-12 Early theories of metal cutting attributed the influence of sulfur to a lubricating effect. It is now apparent that the influence of the nonmetallic inclusions and their properties on crack initiation, deformation in the shear zones, and boundary films must also be considered in relation to the machining process. This paper presents the results of studies conducted to relate machinability to the various sulfide phases which occur in stainless steels. This work has led to the development of alloys with improved machinability, and has generated information on the effects of inclusions on metal cutting processes. Effects of sulfide inclusions and steel composition on other important metallurgical properties are also discussed. MATERIALS For drill machinability and inclusion studies, 10 lb laboratory heats were melted in an air induction furnace. These heats were made with sulfur contents be tween 0.10 and 0.50 pct and manganese contents be tween 0.05 and 3.0 pct. Residual elements were added to the heats in amounts typical for commercial steels. The typical compositional range covered by the heats is shown below: C Mn P S Si Ni Cr Mo Cu N 0.10 0.05 0.007 (M0 0.40 0.40 13.0 0.20 0.10 0.03 3.0 0750 The laboratory ingots were forged in the temperature range of 1800" to 2100°F to 3/4-in. sq bars, and all bars tempered to a hardness aim of 200 Bhn prior to testing. Because of differences in composition and tempering response, the tempered bars showed some variation in hardness (175 to 275 Bhn) as well as variations in delta ferrite content (0 to 50 pct). Composition, hardness, and delta ferrite content were considered in the analysis of the machinability data. Additional tests involving tool-life evaluation and determination of other properties were conducted on materials from commercially melted and processed 15-ton electric furnace heats. TESTS AND PROCEDURES Machinability of the laboratory heats was evaluated in a drill test. In this test, 1/4-in. diam holes, 0.4 in. deep, were drilled alternately in a test bar and in a standard bar for a total of four holes in each. This sequence was repeated three times using a freshly sharpened drill each time. The average time required to drill a hole in the test bar was compared to that for the standard bar. A drill machinability rating was assigned to the test bar relative to a rating of 100

Jan 1, 1970

By D. H. Desy, L. C. Fincher

The magnesium-rich end of the Mg-Ti phase diagram was investigated. The liquidus, solidus, and solvus boundaries to 1 pct Ti were established. All alloys were prepared by saturating molten magnesium with titanium in a consumable titanium crucible under inert gas maintained at 230 psig. The liquidus of the Mg- Ti system was determined by analysis of dip samples taken from 700° to 1300°C under equilibrium conditions in a pressurized inert atmosphere furnace and by analysis of small ingots rapidly poured and quenched from 1400° to 1500°C. The solubility of titanium in magnesium ranged from 0.018 wt pet Ti at 700°C (0.012 wt pet at 650°C by extrapolation) to 1.035 wt pet Ti at 1500°C. The solidus for compositions ranging from 0.03 to 1.00 wt pet Ti was determined to be 650° ± 1°C by thermal analysis. The titanium solid solubility values ranged from 0.08 wt pet at 350°C to 0.19 wt pet by extrapolation to 650°C. The freezing reaction is peritectic. No intermetallic compounds were found in the system; the phase in equilibrium with molten magnesium saturated with titanium was found to be titanium with magnesium in solid solution. Solid titanium will dissolve at least 1.32 wt pct Mg. PREVIOUS investigations of the Mg-Ti system have shown considerable disagreement on the solubility of titanium in liquid magnesium. Furthermore, the solid solubility of titanium in magnesium has not been well established. Liquidus curves for previous work and for the present investigation are shown in Fig. 1. Aust and Pidgeon1 used a dip-sampling method on molten magnesium held in equilibrium with solid titanium under a protective atmosphere to determine the solubility and found that it ranged from 0.0025 wt pet Ti at 651°C to 0.015 wt pet Ti at 850°C. Eisenreich2 introduced titanium into molten magnesium by means of TiCL4 adsorbed on BaCl2. Ingots were then cast at various temperatures. Making the assumption that only the titanium dissolved in magnesium at the time of casting was soluble in H2SO4, Eisenreich determined the solubility of titanium in molten magnesium to range from 0.003 wt pet at 655°C to 0.115 wt pet at 800°C. Eisenreich also determined the solid solubility of titanium in magnesium to be 0.015 wt pet at room temperature and 0.045 wt pet at 500°C. Since the solid solubility just below the freezing temperature for the bulk of the alloy was much larger than the liquid solubility just above the freezing temperature, Eisenreich concluded that the freezing reaction was peritectic. Obinata et al.3 equilibrated molten magnesium with titanium in hermetically sealed titanium containers which were then furnace-cooled. The titanium content of the magnesium was then determined and found to range from 0.170 wt pet at 700°C to 0.85 wt pet at 1200°C. No intermetallic compound was found in the system. The Armour Research Foundation4 determined two points on the solvus by electrical resistivity methods: 0.00057 wt pet at 200°C and 0.0008 wt pet at 300°C. At higher temperatures, data were meaningless with no trends observable. The authors of this report believed that the lack of significant data at the higher temperatures was due to variations in specimen geometry, although there was no positive evidence to verify this supposition. The present investigation was undertaken to clarify the uncertainty in both the liquidus and solvus of the magnesium-rich end of the Mg-Ti system. EQUIPMENT AND MATERIALS The equipment used in this investigation, with some modifications, was essentially that used by Crosby and Fowler5 in their determination of part of the Mg-Zr phase diagram. The equipment, as modified for this work, is shown in Fig. 2. It consists of a sealed furnace chamber which can be pressurized with inert gas so that melts can be made above the boiling point of magnesium at atmospheric pressure. Melts are made by induction heating in a titanium crucible which, after diffusion of sufficient magnesium into the walls of the crucible to saturate the titanium at the sampling temperature, comprises the solid phase in equilibrium with the molten magnesium. Dip samples may be taken with the sampling tube, or the entire furnace may be tilted so that ingots may be poured into a mold in the side chamber. The principal difference from the earlier apparatus is in the thermocouple, which in the present equipment is enclosed in a protection tube and immersed directly in the melt. The tips of both the thermocouple protection tube and the sampling tube, which dip into the melt, are made of high-purity titanium. The 4 1/2-in.-long titanium tip of the sampling tube is threaded into a steel tube, O in Fig. 2, which extends through the top of the furnace. To determine whether the temperature at the tip of

Jan 1, 1969

PHILIP D. BLOCK, JR., vice president of Inland Steel Co., visualizes a fine future for the Menominee Range of the Upper Peninsula of Michigan. He sees a future unclouded by threat from foreign ore imports or the development of low grade ore processing in Minnesota. The statement was made during the opening of Inland's new Cayia mine near Crystal Falls. Inland, according to the vice president, is planning to use an increased amount of the high phosphorous ores found on the Menominee Range. He said that other steel companies will probably do the same, because the steel industry has learned how to use ores of high phosphorous content. He said: "I do not mean to imply that we can use an unlimited amount of high phosphorous ores or that we can burden our blast, furnaces with 100 pct high phosphorous ores, but we have reached the point where we can absorb a much larger percentage of these ores without any detrimental effects. Foreign ores and lowgrade Minnesota ores cost too much to offer real competition, Block said. Transportation costs from the Menominee range to steel producing centers in Chicago and on Lake Erie are less than for any other range in this country. In the meantime, the American operators of the Bomi Hills iron ore mine in Liberia, have reportedly signed a new agreement with the Government. Several months ago, President Tubman of Liberia expressed a definite dissatisfaction with the original contract. Informants state that the agreement only needs the approval of the Export-Import Bank, which loaned Liberian Mining Co. $4 million to develop the iron ore properties. Majority stockholder of the Liberian Mining is Republic steel, with 61.57 pct of the stock. Under the new contract, the Liberian Government will start to share in the profits when the indebtedness is liquidated and the return of invested capital accomplished, or April 1, 1957, whichever is earlier. Under the old agreement the Liberian Government received a 5 cent per ton royalty and an additional sum based on the price of pig iron. The royalty rate reached more than 17 cents per ton this year. After debt liquidation the Liberian Government will receive 25 pct of net profits for the first five years; 35 pct for the next ten years; and 50 pct thereafter. Until the Government starts to share in profits it will receive a royalty of $1.50 per ton in U. S. currency, in addition to royalties provided for in the old agreement.

Jan 1, 1952

By AIME AIME

THE Committee on Elimination of Waste in industry came into existence from a speech in Washington by Mr. ,Hoover, in November, in which, he said: It is primary to mention the three-phase waste in production: first, from intermittent employment; second, from unemployment that arises in shifting of industrial currents; and third; from strikes and lockouts. Beyond this elimination of waste there is another field of progress in the adoption of measures for positive improvement in production.

Jan 1, 1921

By G. A. Reinhardt, H. J. Cutler

ThE Youngstown Sheet & Tube Co. has produced a large tonnage of 0.35 to 0.45 carbon forging steel, the acceptance of which was based on the physical properties of test specimens obtained by forging the original 5 3/4-in. (14.5 cm.) square bloom to a 3/4-in. (1.9 cm.) round. Annealed and tempered specimens were required. The test bars were annealed by heating from 900" to 950' C. and cooling slowly in mica. The test bars were tempered by heating to 825' to 875" C., quenching in water, and drawing to 515" to 535" C. Immediately after heat treatment, the test pieces were machined to a diameter of 0.534 in. (1.38 cm.) and tested. Very good physical properties were obtained and no difficulty was experienced in meeting the specifications called for. UlTimate Strength.. Elongation, Lb. pER Sq. In. PEE Cent.. in 4 In. Not LeEs Than Annealed specimens.............. 78,230 to 92,450. 18 Tempered...................... 120,000 to 149,350 9 After experience on this material, production of slightly higher carbon forging steel was started. The method of testing this material required that test blooms be either normalized or annealed. The normalizing consisted in heating to 850" to 900" C. and cooling in still air; the annealing, in heating to 850" to 900" C. and cooling in the furnace or in mica. From the treated bloom, the test pieces were taken either by core drilling or by sawing from points midway between the edges and the intersection of the diagonals. The cores or blocks were turned to a standard 2-in. test piece with a diameter of 0.564 in. and tested without further treatment. The physical requirements of the test pieces were: yield point, pounds per square inch minimum, 44,800; ultimate strength, pounds per square inch, 89,600 to 112,000; elongation, per cent. in 2 in. not less than 17. Difficulty was encountered as soon as work on this material was started. Many precautions and refinements were instituted but it was found very difficult to secure the required elongation.

Jan 1, 1920

By Carl S. Westerberg

Coal preparation practice and trends follow, among other factors, production trends in any given area. Considering an area the size of a state, some broad predictions may be made after a review of the annual production records. As this paper is concerned with coal cleaning in Utah, data on its production record are pertinent. Table 1 shows the percentage relation of coal production in Utah to the national total as a single figure up to 1935 which includes all recorded production. From 1935 through 1947 these data are presented by years. It is evident from these data that the production of Utah coal is ascending. The reason for this trend is industrial growth in the West resulting in a population shift which accounts for more people than the normal increase would supply together with Utah's relatively fortunate geographical location and its abundance of good-quality coal. Utah is also hopeful of supplying more coal in the future for West Coast power generati0n.l

Jan 1, 1949

By Gerard Matthes

ONLY in recent years has any practical headway been made in the application of aerial photography to geological problems, and up to the present time its principal value to the geologist and mining engineer has been in "areal geology;" i. e., the study of formations as revealed at the surface. The object of this paper is to set forth briefly the principal advantages that may be derived from aerial photographic data in geological work and to serve in a measure as a guide to those who may be con-templating its use. Geophysical prospecting has for object the locating of mineral under the surface. Inasmuch as the geologist's chief complaint in life is a dual one-inability to see under the surface and inability to visualize comprehensively what he does see on top of the ground-geophysical prospecting coupled with aerial photography should do much to lessen his burdens. To what extent aerial photography can be made a useful adjunct to geophysical prospecting remains to be proved, but the inference drawn here is that it holds many alluring possibilities. To avoid disappointments, it should be stated at the outset that to the :geologist or mining engineer an aerial photograph or mosaic is only a tool, the effecient use of which he must set out to master. Upon his skill and ingenuity in applying it to particular problems will depend largely the value of the results that he will obtain. Under the most favorable conditions an aerial mosaic or even a few loose photographs, because of the exceptionally comprehensive oversight which they afford of field data, such as dips and strike observations at isolated outcrops, local indications of faulting, mineral and fossil finds, greatly facilitate study and correlation, save much tedious foot work, and may repay their cost many times. Even so, types of country may be found where the most, skillful use of the best of pictures will produce results so meager as to render the cost of aerial photography entirely unwarranted.

Jan 1, 1928

By Roger E. Barthelemy

PRIMITIVE mining and metallurgy has today almost disappeared. Probably the only remaining tribal tin mining and smelting is practiced by the Laotian natives in one of the less known tin areas of the world. This district lies almost a thousand miles from the sea along the Mekong River, one of the longest rivers in the world, that marks the border between Siam and Laos, one of the five states forming French Indo-China. Less than twenty years ago it took more than two weeks' travel on elephant-back to reach the spot and today it still takes many days of travel, using all kinds of transportation from automobiles to native

Jan 1, 1938

By A. M. Gaudin

THE so-called Kick law' is generally accepted to . mean that for each reduction to one-half in particle diameter, in a unit weight, the same amount of work is required. In crushing-efficiency calculations on crushing tests it is customary, when basing the calculation on Kick's law, to assign ordinal numbers to each standard sieve size. These ordinal numbers increase by a constant difference with each successive sieve aperture, because standard sieve apertures are in constant ratio. Minus 200-mesh is generally assumed as equivalent to 37 microns in size. By definition, the ordinal number multiplied by the per cent material of any size is equal to the energy units in the material of that size in a unit weight of sample. The sum of all energy units is the energy units content of a unit weight of sample, whether it be crusher feed or product. The difference between the energy units in the product and that in the feed is the tangible result of the work input per unit weight of feed. From this the amount of work necessary for one energy unit may be calculated. This has been done for a quartz crushing-test made at the Intermountain Experiment Station of the U. S. Bureau of Mines at Salt Lake City, in which the net work going to crushing was carefully measured. The results of this crushing test are given in Table 1.'

Jan 1, 1929

By Gerard C. Gambs

The electric utility industry is the largest customer of the U.S. coal industry, consuming nearly 50% of present coal production. By 1980, the electric utilities are expected to burn over 500 million tpy of coal or 75% of total coal production. When coal is burned in electric utility plants, ash is produced in one of several forms. These include fly ash, bottom ash and bottom slag. At the present time, approximately 20 million tons of these ashes are produced and must be disposed of by the utilities at a cost of 50[c] to $2 per ton. In 15 years, more than double this quantity will be produced. Only a small quantity of this ash is put to any practical use. Much remains to be done about expanding uses for fly ash and bottom slag.

Jan 1, 1967

By J. J. Carrigan

DURING the experimental stage in our use of the electric cap lamp in the Anaconda mines at Butte. Mont., we were somewhat concerned as to how the spitting of fuses would be carried out if we completely eliminated the open-flame light. This problem was at once given serious attention by the engineering research department and some thought was given to having all blasting done by the use of electric delays, which has been the practice for some years

Jan 1, 1936

By AIME AIME

On Nov. 11, 1909, M. Alexandre Pourcel, of Paris, France, upon the proposal of a large number of distinguished members, and the unanimous recommendation of the Council, was elected by the Board of Directors an Honorary Member of the Institute. M. Pourcel has devoted forty-three years to the metallurgy of iron and steel ; and the work which he did between thirty and forty years ago constitutes an important part of the founda¬tion of the practice of to-day. Among his striking contribu¬tions are : (1) his perfection, in 1869, of the manufacture of high-grade ferro-manganese in a carbon-lined open-hearth furnace, instead of the costly crucibles previously used; (2) his discovery, in 1874, of the method of making solid steel cast¬ings; (3) his manufacture, in 1875, of ferro-manganese and silico-spiegel in the blast-furnace; and (4) his anticipation, in 1875, of modern American blast-furnace practice, by the pro¬duction, in a very small furnace, of Bessemer pig containing 2.5 per cent. of silicon, from a burden yielding only 46 per cent. of iron, and with a consumption, per ton of pig, of only 1,8401b. of coke, containing 15 per cent. of ash. These brilliant pioneer achievements, together with his contributions to cur¬rent technical literature, won for him the Bessemer gold medal of the Iron and Steel Institute ; the great" medal of honor," which is the highest award of the French Society of Mineral Industry, and other gold medals, as well as the distinction of honorary membership of the Comité des Forges de France, which was conferred upon him in 1891. In recent years, M. Pourcel has been instrumental, as consulting engineer of the Société de Commentry-Fourchambault, at Decazeville, France, in an extraordinary development of the manufacture of special steels. The Invar plant, of this company, is said to make a greater variety of such steels (includ-

Dec 1, 1909

By G. F. Comstock

A serious disagreement as to the effect of titanium on the hardenability of steel exists in published references to this subject. Kramer, Hafner and Toleman reported' that acid-soluble titanium decreased creased the hardenability, with multiplying factors less than unity according to [ ] Grossmann's system for calculating hardenability from the composition. Crafts and Lamont, on the other hand, showed2 how titanium increased the hardenability, with multiplying factors up to nearly 1.7 for about o.' per cent titanium, though reducing the hardenability with higher titanium. Their data, however, were obtained almost exclusively from steels containing more than 2.4 per cent manganese, and thus should be considered as applying mainly to manganese steels. Likewise, the results of Kramer, Hafner and, Toleman regarding titanium are subject to the limitation that although they eliminated the effect of the insoluble titanium compounds from their calculations, they did not make a similar correction for the carbon that was combined with titanium and therefore occurred in a similarly ineffective form. It is suggested by the literature referred to that titanium may have different effects on hardenability, depending on the mode of its occurrence in the steel. The different effects on strength, ductility, etc., have already been discussed by the author.3 In the present discussion some comparisons, on the basis of hardenability as revealed by the Jominy end-quench test, are given between three titanium and two non titanium steels heat-treated in the same ways, and between other titanium steels heat-treated in several different ways. COMPARISON OF PLAIN-CARBON, VANADIUM AND TITANIUM STEELS The five steels used for these experiments were commercially melted and rolled products received in the form of 1.5-in. rounds from three different mills. Their analyses are given in Table I. Steels 2, 3, and 4 are from the same basic electric heat, containing 0.009 per cent of phosphorus and the same amount of sulphur. They were made by, adding aluminum and low-carbon ferrotitanium to different ingots. No. I is a plain-carbon coarse-grained S.A.E. 1040 steel made by the basic open-hearth -process. No. 5

Jan 1, 1945