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By L. W. Rowe, S. S. Cole

A laboratory bench scale unit is described whereby finely divided chlorinatable residues are held for a short period by a restraining bed of a coarse-grained ore of comparable composition to permit 'flash' chlorination of the high surface area powder. Results on chlorinating a finely divicled titania residue using rutile sand as the restraining bed showed that 92 pct utilization of chlorine and equivalent conversion of TiO2 in the fine residue to Ticl4 were attained with a dust loss of about 3 to 4 pct and an equivalent amount of ch1om'nation of the titanium values in the restraining bed. THE chlorination of coarse grain titaniferous ores; i.e., 20 to 150 mesh sizes in fluidized beds is practiced commercially.' One effective method found for the chlorination of a very fine material in a fluidized bed is the "flash" chlorination technique.' By charging the finely divided charge material into the bottom of an established bed of optimum sized rutile, ilmenite, titanium beneficiate, or even an inert material such as sand, chlorination occurs before the dust can pass through the bed. The major requirement is that the bed be less chlorinatable than the charge. In this process, the charge consists of a finely divided (between one and 50 µ) titania residue obtained from a titaniferous ore beneficiation process. The charge is blended with a 20 pct wt basis addition of 20 to 60 .mesh size low volatile coke (to minimize hydrogen chloride formation) and fed to the bottom of the bed with the chlorine gas stream. A ball check device is used to permit entry of the charge and prevent the bed from discharging when the gas flow is cut off. The coarse pieces of coke serve to reduce compaction in the charge mixture and permit sat]sfactory feeding without plugging or jamming. Feed and gas rates are adjusted to provide for complete reaction of the charge material, with 90 to 95 pct chlorine efficiency, and maintain a gas flow in the range of 0.4 to 0.6 ft per sec. The equipment consisted of a 3-in. diam mullite tube enclosed in an electric furnace. A bow-shaped 3/4 in. Saran tube fed the charge from an air lock type of feed hopper (to prevent the escape of the chlorine gas into feed bin) to the bottom of the bed. The charge rate was set by providing a small awiliary hopper below the feed hopper where a weighed portion of the charge could be discharged in a specified time interval into the main chlorine stream. The chlorine rate was measured by a flowmeter. The reaction tube was filled with a bed of Australian rutile ore, this restraining bed serving two purposes; i.e., it rapidly heated the fresh charge to the reaction temperature and retained the particles in the bed for a sufficient time for selective chlorination to proceed. Due to the fine particle size and open, porous structure of the charge, this reaction was almost instantaneous, and, with proper adjustment of feed and gas rates, very little fine material passed through the bed without reacting and only a very small fraction of the restraining bed was chlorinated. A typical reaction procedure was to fill the bench scale fluidized bed unit with a 1 kg charge of Australian rutile ore analyzing 95.5 pct TiO2, 0.6 pct FeO, a beach sand deposit 40 to 150 mesh size. When fluidized, the bed was approximately 2 ft in depth. The ore was fluidized with a 1:l mixture of chlorine and nitrogen at a rate of 0.40 ft per sec. This gas mixture was necessitated by the comparatively short bed depth; a larger unit, with a deeper bed, could be fluidized with chlorine alone without significant free chlorine loss. Feed rate was 8.0 g per min of beneficiated ilmenite analyzing 85.0 pct TiO2, 2.6 pct FeO plus 1.6 g per min of 20 to 60 mesh petroleum coke. The

Jan 1, 1962

By Albert E. Wiggin, Frederick Laist

Page I. Introduction............................470 II. The Sources and Amount of Slime................470 II. The Composition of the Slime..................471 IV. The Experimental Development of the .Anaconda Slime Plant.. 471 1. The Great Falls Slime Plant and Experimental Work......471 2. The Experimental Work Done at Anaconda..........473 (a) SlimeThickening Devices.............. 474 (b) SlimeConcentrators................. 475 (c) Dewatering the Slime Plant Concentrate......... (d) The Use of Chemicals to Accelerate the Settlement of Slime........................ 478 (e) The Effect of Temperature upon the Settlement of Slime 478 V. A Description of the Anaconda Slime Plant........... 479 1. A Diagrammatic Flow Sheet of Plant............. 480 2. The Slime-Thickening Division................ 480 3. The Concentrating Division.................. 481 4. The Concentrate-Dewatering Division............. 483 5. General Data........................ 484 I. IntRoduction The new slime-concentrating plant at the Washoe Reduction Works, Anaconda, was put into operation during March, 1914. This plant, which has a capacity of 26,000,000 gal. of slime pulp carrying 2,500 tons of solid matter per day, consists of Dorr thickeners and Anaconda multiple-deck slime concentrators. This plant is the culmination of a great deal of experimental work extending over a considerable period of time, which , work will be described briefly in the following pages. II. The Sources and Amount of Slime Up to the beginning of this year, the ore from the Anaconda company's mines in Butte, Mont., has been concentrated both at the Great Falls

Jan 1, 1915

By Edward L. Wilson, Keshavan Nair, Ranbir S. Sandhu

In planning and designing of underground excavations and construction, it is of considerable importance that the stresses and displacements in the rock mass subjected to arbitrary sequences of unloading and loading be within allowable limits. For determination of the stress and displacement fields, the usual approach is to treat the rock as an elastic material and to apply the principles of the theory of elasticity. However, analytic solutions are available only for a limited class of problems of simple geometry and idealized material properties. Nonhomogeneity and anisotropy of material coupled with complex geometrical configuration and initial stress fields that are almost always preexistent in rock masses at great depths, render the problem intractable by analytical methods. Approximate solution techniques using numerical procedures have, therefore, to be resorted to. The finite element method as applied to plane stress analysis was introduced by Clough.1 It has developed into a powerful tool for the analysis of various field problems in structural and continuum mechanics. The method is well documented in the literature2-6 and, therefore, its historical development will not be discussed here. Wilson's analysis of the plane stress/strain problem has found extensive use in the area of soil and rock mechanics including stresses around underground openings; stresses and displacements in dams, foundations, etc.7-11 In his analysis of the axisymmetric solid,3 Wilson proposed a procedure to allow for certain cases of nonlinear material properties. In this chapter, the develop-

Jan 1, 1972

[A Aamodt, H. C., A55 C Sales, Great Lakes Carbon Corp., 18 E. 48th St., New York, N.Y. Aamot, Olav Crone, M29 2126 M4, Galveston, Texas Aaronson, Hubert I., M47 E Prin Res Engr, Ford Motor Co., Met. Dept., Sci. Lab., Engrg. Staff, P. O. Box 2053, Dearborn, Mich. Aase, Glenn D., M54 D Prin Engr, Air Pollution Control Dist., 1480 Mission St., San Francisco 3, Calif. Abbett, W. A., Jr., M56 8629 Beverly St., Duluth 8, Minn. Abbey, Robert G., M56 138 Dartmouth Rd., Bala Cynwyd, Pa. Abbott, A. G., Jr., J52 E Test, Dev Engr, Chrysler Corp. Missile Div., P. O. Box 2628, Detroit 31, Mich. Abbott, Mark L., A58 Rep, General Refractories Co., 208 S. LaSalle St., Chicago, Ill. Abbott, W. K., J58 E Dev Met, Int'l Nickel Co., Inc., 67 Wall St., New York 5, N.Y.]

Jan 1, 1961

By J. M. Sands

THE state of Kansas had a daily average crude-oil production of about 87,000 bbl. at the beginning of the year. This showed a steady but consistent decline during the 12 months, so that the daily average production at the end of the year was slightly over 68,000 barrels. GREENWOOD COUNTY THE most active development in Kansas during the year was in Greenwood County, in a line from near Sallyards in T 25-R 9 to east of Madison in T 22-R 11. The main part of this development has been in a succession of pools beginning at the south with the Polhamus pool in 34-24-9 and 3 and 4-25-9; Thrall pool in 28, 29, 32 and 33-23-10; Burkett pool in 13, 23, 24 and 26-23-10; Seeley and Wick pool in 22, 27, 28,. 32 and 33-22-11 and 5, 6, 7, and 8-23-11; Frohm pool in 11, 14 and 15-22-11; Madison pool in 31 and 32-21-12 and 6, 22, 12 and 1-22-11. Some of these pools have two or more sands, locally called Bartlesville and Burgess Sands. They range in depth from 1850 ft. near Madison to 2450 ft. near Sallyards, the general dip being to' the west. The thickness of these sands run from 20 to 100 ft., the initial production of the wells being 50 to 1000 bbl of 40-gravity oil or better.

Jan 3, 1924

By J. C. Bradley

THE relation of annealing temperature to conductivity of copper wire has been determined.1 Conductivity hard was 98.26 per cent. After a 10-min. heating at 200° C. it was 98.69. By annealing 10 min. at 300° C. a large increase, to 100.93, occurred. Maximum conductivity, 101.15, was attained after a 500° C. anneal; thereafter it decreased to 100.53 after a 950° C. anneal. If copper is gassed the decrease is much more than this. MATERIAL AND METHOD The work was done on high grade electrolytic copper, 99.942 per cent. copper-plus silver, silver 0.0008 per cent. It was hot-rolled to 3 in., then cold drawn to 0.080 in. The wire was cut into 25 5-ft. lengths and numbered 1 to 25 as cut. Four samples were tested hard. The others were wound into 5-in. diameter coils. For the 100° C. heating a coil was put into water, the water brought to boiling, and the wire kept at this temperature for 10 min. For the higher temperatures the coils were placed in envelopes of sheet copper, a little water added, and the envelopes sealed by folding over the edges twice, and hammering them together. This kept the air out very well. The envelope and wire were brought to the desired temperature; this was maintained for 10 min., then the whole was water-quenched.

Jan 1, 1927

By E. A. Gulbransen, W. S. Wysong

THE behavior of molybdenum and its surface oxides in oxidizing and reducing gas atmospheres and in high vacua at elevated temperatures is a question of scientific and technical importance The use of molybdenum as a metal or as an important component in alloys in oxidizing atmospheres at elevated temperatures has been limited because of the unprotective nature of its oxide film and the volatility of this oxide at moderate temperatures. This communication will present results of a vacuum microbalance study 1,2 of the following problems. (11) the oxidation kinetics in the temperature range of 250° to 450°C; (2) the reduction with pure hydrogen of thin oxide films formed on molybdenum; (3) the volatility of the thin oxide films, and (4) the vacuum oxidation of molybdenum at high temperatures. Molybdenum is an interesting metal to study for the following reasons: (I) although the oxide-to-metal-volume ratio is greater than one, the metal is not considered protective; (2) the metal oxidizes readily at temperatures of 250°C and higher; (3) the oxides of the metal are reduced at temperatures as low as 500°C by pure hydrogen; (4) the oxide MoO3 melts at 795°C; and (5) the oxides of molybdenum are volatile at moderate temperatures. The following variables are studied in the oxidation kinetics. time, temperature, pressure, surface preparation, surface area, concentration of inert gas in the lattice, cycling procedures in temperature, vacuum effect and high temperature vacuum oxidation The general interpretation of many of these factors has been previously discussed. LITERATURE The oxidation of molybdenum has not been studied critically. Although" many studies have probably been made on the kinetics of the oxidation process, none has been reported in the literature available to us. The crystal structures found in the oxidation of molybdenum have been studied by Hickman and Culbransen 4 Their results showed that MoO2 is the oxide which is stable in contact with the metallic subgtrate throughout the temperature range 300 to 700°C. As the film thickens in the low temperature range, MoO3 becomes predominant on the surface. Above 400°C, Mo03 is no longer observed, Mo02 being the only oxide found. Hagg and Magneli5 have shown from an X ray study that the a-phase, orthorhombic MoO3 is stable up to 1050°C. Two other phases, ß and ß', with compositions close to Mo02 90 are also obtained The formula for the ß phase is not given but that of the ß' phase is defined as Mo9026. The ß' phase is found to be built upon a monoclinic unit cell. A -?-phase is isolated from a preparation M00275 heated for 17 hrs at 670°C. This phase is

Jan 1, 1947

Idaho Bureau of Mines and Geology, University of Idaho, Moscow, Ida. John W. Finch, Director. A list of publications will be sent upon application. A series of Bulletins and Pamphlets have been issued by the Bureau to date since 1920 Of the Bulletins, six are out of print, and a charge is made for eight. Each of the Bulletins, in the main, treats of the geology and resources of a particular district in Idaho, as follows (only available Bulletins listed): Bulletin 1, South central Idaho (1920), 15 cents, 7, North central Idaho (1924), 50 cents, 8, Bonneville, Bingham and Caribou counties (1924), 50 cents, 9, Boise Basin (1924), 50 cents; 10, Boundary County (1926), 50 cents; 11, Region about Silver City (1926), 50 cents; 12, Clark Fork district (1930), 50 cents, 14, Eastern Cassia County (1931), 50 cents, Press Bulletin 15, Teton County (1927), Bulletin 16, Melon Valley near Buhl (1927); 17, Concerning land slips near Whitebird, Idaho (1928) The 37 Pamphlets are issued free of cost, and each treats, also, in the main of the geology and resources of a particular district in Idaho Nos 1, 2, 3, 4, 5, 7, 8, 10, 17, 18, 20, 22, 25, 26, 30 and 35 are out of print Of those available, attention may be called to Pamphlet 6, Reported platinum occurrences near Coeur d' Alene (1925), 11, Bruneau River Basin, 12, Power and Oneida

Jan 1, 1933

By E. J. Wasp, N. T. Cowper, R. A. Davis, W. F. McDermott

On October 26, 1967, the world's first long distance iron ore slurry line was put into service by Savage River Mines. The commissioning of this $5 million installation climaxed three years of development, testing, and construction. The mine and concentrator are located approximately 30 miles from the town of Waratah in a rugged semi-mountainous terrain. The open pit mine will produce approximately 5 million long tons a year of crude ore, which is ground in autogenous mills, separated magnetically, thickened and prepared for the pipeline. The 53-mile pipeline transports the 2,250,000 tons of concentrate north to Port Latta. The Port Latta facilities include the receiving, storage and thickening equipment for the slurry as well as filtering, balling and pelletizing equipment to produce the 2,250,000 tons of high grade iron ore pellets. Five vertical shaft furnaces are used for pelletizing.

Jan 1, 1969

By A. L. Field

A. W. FAHRENWALD, Socorro, 'N. M. (communication to the Secretary*).-When asked to discuss Mr. Feild's paper, I felt most highly complimented to have the privilege of commenting on such a worthy and needed piece of apparatus. In consideration of the importance of the viscosity of blast-furnace slags and the relation existing between the' melting point of a slag and its viscosity, the introduction of this apparatus should be a welcome means or assistant in the study of the physical properties of a slag. Up to the present time, it is A fact that this side of the practical working of the blast furnace has been sadly neglected by those investigating slags. It is easily seen that the fluidity of a slag is of as great importance as its melting point. It is not necessarily true that a slag having a low melting point will have a correspondingly low viscosity or be highly fluid. For example, a slag having a melting point of 1,100° C. may have to be superheated to, say,1,300° C., in order to have as high a fluidity as another slag whose melting point is, say, 1,250° C. The latter in this case would be the more economical. This point has been brought out very nicely by Mr. Feild. Before discussing this paper further, I think it will be well to outline some of the points, a discussion of which may be in order:

Jan 3, 1917

By Gordon H. Geiger, J. Bruce Wagner

Electrical conductavity and therrnoelectvic nzeasuretnents on synthetic hematite slabs with 0.01 to 0.90 at. pet Ti and with 0.30 at. pet Ca were made. Additions of titanium and of calcium both increased the electronic conductivity with titanium yielding greater n-type behavior and calciurn p-type behavior. Reduction studies of hematite to magnetite in CO-CO2 atmospheres between 600° and 900°C initially exhibited linear kinetics. These linear rates were increased by additions of titanium and decreased by calcium. IN recent years many studies have been reported in the literature on the kinetics of the reduction of hematite and magnetite to iron. In addition, Hansen and Josephl and Schenck and Schultz2 have reported studies on the reduction of hematite to magnetite, the first step in total reduction to iron. In order to evaluate the results of the studies of over-all reduction in terms of the actual mechanism of the reaction and to define further the important factors in the rate- controlling mechanism of the magnetic roasting reaction, the following experiments were undertaken. Specimens of undoped hematite and hematite containing titanium or calcium in solution as doping agents were reduced to magnetite in CO-CO2 mixtures. In addition, electrical-conductivity measurements were correlated with the reduction kinetics using concepts of defect solid-state chemistry. EXPERIMENTAL Fisher certified Fe2O3 powder was used to make specimens for both the electrical and kinetic studies (see Table I for analysis). Doping with titanium and calcium was accomplished by adding TiO2 and CaO powders to the Fe2O3 powder. The powders were mixed in a Waring blender for minimum times of 1/2 hr. Satisfactory blending was achieved based on comparison of analyses of individual specimens af- ter reduction. The specimens were formed in a steel die using opposed punches with a rectangular opening 10.0 by 40.0 mm. The Fe2O3-TiO, platelets were pressed cold at 16,000 psi. They were sintered for approximately 16 hr at 1075°C in air, in accordance with information in the literature3, 4 on the time and temperature needed to obtain solution of the titanium in the hematite. The Fe2O3-CaO mixtures were first cold-pressed at 20,000 psi and sintered for 3 hr at 1225°C to insure solution of CaO. This material was then ground to -325 mesh in a 6-in. ball mill and the resulting powder was used to make platelets in the same manner as above. The sintered platelets were usually between 1/16 and 1/8 in. thick. They were ground on a carborundum wheel and polished on 2/0 paper. Typical dimensions of the kinetic-study specimens were 1.6 by 0.8 by 0.05 cm, and a typical weight was 0.3 g. Conductivity and thermoelectric specimens were approximately the same size, but were subjected to further sintering in order to ensure maximum densification. Finally, all specimens were measured to the nearest 0.0005 in. and weighed on a Mettler H-15 balance to the nearest 0.0001 g and the density calculated. The average density of the specimens used for the reduction studies was 4.87 g per cc, or 7.1 pet total porosity. The standard deviation ranged from 0.14 to 0.063 g per cc within a composition group. In the present study, the apparent surface area as measured with a micrometer was taken as the true surface area. The chemical analyses for calcium and for titanium within a group showed maximum variations of 50.04 pet from the average values used in Figs. 9 and 11. In order to suspend the specimen from the balance for the kinetic studies, a hole, 0.03 in. in

Jan 1, 1965

By J. C. Reed, J. M. Hansell

Cinnabar was discovered in southwestern Arkansas on Little Missouri River in sec. 1, T.7S., R.26W., in April, 1930, and near Antoine Creek in sec. 28, T.6S., R.23W., some 15 miles farther east in May of the same year. It was not, however, until June, 1931, that cinnabar was identified as such in a specimen from the original discovery area sent to W. M. Weigell by Walter F. Hintze of Murfreesboro. Almost simultaneously2, in July, 1931, Moritz Norden of Hot Springs identified specimens from the Antoine Creek area as cinnabar. Immediate interest in the district followed the identification of cinnabar and by January, 1932, the district was known to extend as a mineralized belt about one mile wide trending east-northeast from sec. 13, T.7S., R.27W., in Howard County across central Pike County and into Clark County to sec. 19, T.6S., R.23W., thence extending southeast into sections 33 and 34 of the same township. Since then, cinnabar has been found in sec. 6, T.7S., R.22W., thus giving a total east-west length to the district of approximately 30 miles. Interest focused mainly on the two discovery areas, with the result that mining development has progressed most rapidly in those localities. In the Antoine Creek area the Arkansas Quicksilver Co. has done considerable exploration work and has retorted the high-grade ore so obtained. In the Little Missouri area the Southwestern Quicksilver Co. has had a 12-ton rotary furnace in more or less continuous operation since April, 1932, and has been the largest producer in the district. In March, 1934, the United States Geological Survey began a study of the Arkansas quicksilver district, which was made possible by an allotment of funds from the Public Works Administration. Until

Jan 1, 1935

By J. C. Reed, J. M. Hansell

Cinnabar was discovered in southwestern Arkansas on Little Missouri River in sec. 1, T.7S., R.26W., in April, 1930, and near Antoine Creek in sec. 28, T.6S., R.23W., some 15 miles farther east in May of the same year. It was not, however, until June, 1931, that cinnabar was identified as such in a specimen from the original discovery area sent to W. M. Weigell by Walter F. Hintze of Murfreesboro. Almost simultaneously2, in July, 1931, Moritz Norden of Hot Springs identified specimens from the Antoine Creek area as cinnabar. Immediate interest in the district followed the identification of cinnabar and by January, 1932, the district was known to extend as a mineralized belt about one mile wide trending east-northeast from sec. 13, T.7S., R.27W., in Howard County across central Pike County and into Clark County to sec. 19, T.6S., R.23W., thence extending southeast into sections 33 and 34 of the same township. Since then, cinnabar has been found in sec. 6, T.7S., R.22W., thus giving a total east-west length to the district of approximately 30 miles. Interest focused mainly on the two discovery areas, with the result that mining development has progressed most rapidly in those localities. In the Antoine Creek area the Arkansas Quicksilver Co. has done considerable exploration work and has retorted the high-grade ore so obtained. In the Little Missouri area the Southwestern Quicksilver Co. has had a 12-ton rotary furnace in more or less continuous operation since April, 1932, and has been the largest producer in the district. In March, 1934, the United States Geological Survey began a study of the Arkansas quicksilver district, which was made possible by an allotment of funds from the Public Works Administration. Until

Jan 1, 1935

Cinnabar was discovered in southwestern Arkansas on Little Missouri River in sec. 1, T.7S., R.26W., in April, 1930, and near Antoine Creek in sec. 28, T.6S., R.23W., some 15 miles farther east in May of the same year. It was not, however, until June, 1931, that cinnabar was identified as such in a specimen from the original discovery area sent to W. M. Weigell by Walter F. Hintze of Murfreesboro. Almost simultaneously2, in July, 1931, Moritz Norden of Hot Springs identified specimens from the Antoine Creek area as cinnabar. Immediate interest in the district followed the identification of cinnabar and by January, 1932, the district was known to extend as a mineralized belt about one mile wide trending east-northeast from sec. 13, T.7S., R.27W., in Howard County across central Pike County and into Clark County to sec. 19, T.6S., R.23W., thence extending southeast into sections 33 and 34 of the same township. Since then, cinnabar has been found in sec. 6, T.7S., R.22W., thus giving a total east-west length to the district of approximately 30 miles. Interest focused mainly on the two discovery areas, with the result that mining development has progressed most rapidly in those localities. In the Antoine Creek area the Arkansas Quicksilver Co. has done considerable exploration work and has retorted the high-grade ore so obtained. In the Little Missouri area the Southwestern Quicksilver Co. has had a 12-ton rotary furnace in more or less continuous operation since April, 1932, and has been the largest producer in the district. In March, 1934, the United States Geological Survey began a study of the Arkansas quicksilver district, which was made possible by an allotment of funds from the Public Works Administration. Until

Jan 1, 1935

By J. C. Reed, J. M. Hansell

Cinnabar was discovered in southwestern Arkansas on Little Missouri River in sec. 1, T.7S., R.26W., in April, 1930, and near Antoine Creek in sec. 28, T.6S., R.23W., some 15 miles farther east in May of the same year. It was not, however, until June, 1931, that cinnabar was identified as such in a specimen from the original discovery area sent to W. M. Weigell by Walter F. Hintze of Murfreesboro. Almost simultaneously2, in July, 1931, Moritz Norden of Hot Springs identified specimens from the Antoine Creek area as cinnabar. Immediate interest in the district followed the identification of cinnabar and by January, 1932, the district was known to extend as a mineralized belt about one mile wide trending east-northeast from sec. 13, T.7S., R.27W., in Howard County across central Pike County and into Clark County to sec. 19, T.6S., R.23W., thence extending southeast into sections 33 and 34 of the same township. Since then, cinnabar has been found in sec. 6, T.7S., R.22W., thus giving a total east-west length to the district of approximately 30 miles. Interest focused mainly on the two discovery areas, with the result that mining development has progressed most rapidly in those localities. In the Antoine Creek area the Arkansas Quicksilver Co. has done considerable exploration work and has retorted the high-grade ore so obtained. In the Little Missouri area the Southwestern Quicksilver Co. has had a 12-ton rotary furnace in more or less continuous operation since April, 1932, and has been the largest producer in the district. In March, 1934, the United States Geological Survey began a study of the Arkansas quicksilver district, which was made possible by an allotment of funds from the Public Works Administration. Until

Jan 1, 1935

The accompanying sketch shows the interesting position of Salt Lake City with reference to Western mining areas and justifies its title "The Center of Western Mining." In the last twenty years, the area embraced within a circle of 600 miles radius with Salt Lake City as its center has produced 79.87% of the gold, 91.9% of the Silver, 77.47% of the copper, 53.61% of the lead and 26.55% of the zinc produced in the United States, including Alaska. This area also contains the greatest coal deposits of the continent, some of the greatest oil deposits, great iron deposits and many other important mineral resources. The 600-mile circle contained 69% of the active operators of other than coal mines and 40% of the men employed in mines other than coal mines of the United States, including Alaska, for the four-year period ended with 1923.

Jan 1, 1925

By S. F., French

IN reviewing the design of the ore haulage system for the Morenci project, the reader should bear in mind that the railroad and its equpiment cannot be considered as an independent railroad provided only for the purpose of transporting ore from one point to another, but as an integral part of the operation which begins at the electric shovels loading ore at the mine, and ends where the ore, after having been crushed in the primary crushing plant, is deposited in the bins at the secondary crushing plant. Obviously then, the problem consisted of designing a system that would function to the best possible advantage in complete co-ordination with the other units.

Jan 1, 1942

The Industrial Minerals Division met jointly with the Materials and Equipment Division of the American Ceramic Society at State College, Pa, Sept 24-26 Headquarters were at the Nittany Lion Inn Thurs- day afternoon was devoted to a tour of inspection of the Bell Mine, American Lime and Stone Co , Bellefonte, Pa The party returned to State College for dinner and in the evening the Division's executive committee held a brief session There were four technical sessions Friday morning, Mining, afternoon, Beneficiation, Saturday morning, Industrial Minerals and Beneficiation There was an informal banquet at the Nittany Lion Inn Friday night with 93 present Edward Steidle was toastmaster Brief talks were made by President F C Flint and Secretary Ross Purdy, of the American Ceramic Society, Oliver Bowles, Chairman, Industrial Minerals Division, Adrian Morse, assistant to the president, Pennsylvania State College, and George Otis Smith, past president A I R'I E

Jan 1, 1937

On Sept. 22 to 26, the Institute will hold its 120th meeting in Chicago. The program arranged provides for technical sessions on: Mine Taxation, Non-ferrous Metallography, Coal and Gas, Milling, Oil, Industrial Organization, Geology, Non-ferrous Metallurgy, Mining and Local Resources, Iron and Steel, Symposium on Sulfur Coals, Symposium on Pyrometry. Inspection trips have been arranged to: Gary Steel Plant. La Salle District: Zinc smelters, coal mines, cement works, America's first permanganate plant, many varied industries, scenic trips. North Chicago and Milwaukee: Mining-machinery manufacturing plants, tungsten and molybdenum reduction plants. East Chicago and Whiting: Lead refinery, oil refinery. Franklin and McCoupin: Coal fields. Chicago: Nearly every kind of metallurgical and manufacturing industry. MONDAY, SEPT. 22d Morning Registration, Non-ferrous Metallurgy, Coal and Gas. Afternoon Coal and Gas Milling Industrial Geology, etc. Evening Smoker. TUESDAY Morning Gary. Afternoon Gary. Iron and Steel. Evening Oil, Iron and Steel.

Jan 9, 1919

By N. N. Breyer

A specially built "hard" tensile machine with characteristics permitting the precise detertnination of the drop of the load at the yield point has been used to study the magnitude of the yield-point phenotnenon in prestrained martensitic 4340 steel. A new phenonzenon, the appearance of a secondary yield point, has been observed by holding the specimen at constant strain in the plastic region. Furthermore, it has been found that a series of yield-point drops could be introduced by successive constant strain holds in the plastic region. The isothermal kinetics of the development of the secondary yielding point lave been studied at four temperatures: 24° 0° -18°, and -79°C. From the results of the kinetic investigation, equations for the In a previous investigation1 it was shown that, contrary to generally held opinion, steels of medium carbon content, such as 4340, 4140, and 86B30, in the as-quenched martensitic condition, can be cold-drawn through a die with reductions in area of up to 10 pct without cracking. Tensile specimens of 4340 machined from bars quenched and prestrained in this manner exhibited tensile strengths of about 400,000 psi coupled with 30 pct reductions in area. In addition, it was found that each sample of such steels exhibited a yield point in the quenched, cold-drawn condition. Since these studies were conducted on a commercial hydraulic testing machine of a type which is not well-suited to detailed study of yield-point behavior, it was decided to study this phenomenon more thoroughly on a rigid straining machine. In this new investigation, use of such a "hard" machine not only allowed study of the magnitude of the yield-point drop but also revealed a new phenomenon—secondary yielding of the martensite introduced by stopping crosshead motion after plastic deformation of the sample had begun. The present paper is a report of these findings. MATERIALS AND PROCESSING The material used was a commercial 4340 steel of the composition shown below: 0.41 0.80 0.013 0.019 0.31 0.85 1.76 0.28 1 0.42 0.77 0.015 0.024 0.30 0.84 1.69 0.28 0.08 2 1 = Ladle analysis. 2 = Laboratory analysis. Bars of this steel were processed in the following way: 1) machined to predetermined diameters; 2) austenitized at 870°C for 1 1/2 hr; 3) oil-quenched; 4) cooled to -115°C for 1/2 hr; onset and increase in magnitude of the secondary yielding in this temperature region have been found to fit the relationship ?Ys = Atn where ?Ys is the magnitude of the secondary yield Point in psi, t is the time in seconds, and A and n are parameter characteris-tics of the material. Although the occurrence of the primary and secondary yield points could be rationalized qualitatively on the basis of stress-induced ordering of carbon atoms in the stress fields of dislocations, as postulated in an earlier paper, the kinetics of the secondary-yield-point development were interpreted to indicate that the ordering involves more than just single jumps of carbon atoms from high-energy to neighboring low-energy sites. 5) pickled and lime-coated; 6) drawn through a carbide die. The predetermined diameters were chosen so that drawing through the same die gave the various reductions desired. Tensile specimens of 0.252 in. diam with a 1 1/4 in. gage length were then prepared from the drawn bars and tested. In order to study the stress-strain behavior at the yield point in detail, a rigid tensile machine with a high spring constant was constructed. Columns of large cross section (relative to the specimen cross section) constituted the machine frame. A dc motor was used to drive a screw via a gear reducing train and a "crane" thrust bearing. In this relatively simple device small deformations could be observed un-blurred by the slow response and lower spring constant inherent in hydraulic machines.' A strain-gage dynamometer permitted load changes as small as 8 lb to be read. RESULTS Tensile test samples machined from bars in the as-quenched condition with no subsequent drawing and samples from bars with 3.8 pct reduction after quenching gave stress-strain curves typified by those shown in Figs. I and 2. The time lapse between predrawing and tensile testing varied but usually ranged between 3 to 6 days at room temperature. The strain rate during testing was 0.003 in. per in. per min. The as-quenched curve is seen to have a broad serrated maximum whereas the stress on the specimen prestrained 3.8 pct rose linearly to point A, Fig. 2, fell abruptly to B, and then gradually to C. The abrupt drop to B was accompanied by evidence of incipient necking. The drop of the stress at the yield point in the prestrained samples (A to B in Fig. 2) changed with the percent prestrain, as illustrated on Fig. 3. Although the tensile strength increased continuously with the amount of previous cold drawing, the magnitude of the yield point drop first increased—up to about 6 pct prior reduction—and then decreased. Specimens from bars predrawn more than 8 pct broke in a brittle fashion in the elastic portion of the stress-strain curve.

Jan 1, 1967