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By Jack L. Taylor

WITH the exception of the work of Vogel,&apos; and Rolla and Iandelli, very little information has appeared in the literature on titanium binary systems with the rare earth elements. Rare-earth additions to titanium alloys may possibly parallel the beneficial effects on the physical properties of certain steels. Having this in mind, some knowledge of solubility limits and intermediate phases, if any, would be useful. An investigation of the titanium-rich Ti-Ce system was started. Alloy Preparation The iodide titanium from the New Jersey Zinc Co. and the cerium metal from the Institute for Atomic Research Ames Laboratory used in this work were supplied with the typical analysis shown —iodide titanium: 0.0065 pct Mn, 0.0022 pct Fe, 0.0015 pct Cu, and 0.0042 pct Pb; cerium metal: <0.01 pct Fe, <0.03 pct Si, <0.05 pct Ta, <0.02 pct Pr, <0.03 pct Ca, <0.02 pct Mg, with no trace of Nd, La, or Th. The cerium metal, stored in oil, was washed and scraped just before weighing into capped cups machined from iodide titanium. The cold hearth helium-arc furnace described by Schramm et al3 was used for melting. The alloy buttons from the arc-melted cup were cut in two, mounted, and examined. Homogeneous alloys were demounted and rolled to approximately 1/4-in.sq bars. Sections l/8 in. thick were cut from the bar to provide samples. The Ti-Ce alloy buttons analyzed for cerium were of the following composition: 0.19, 0.36, 0.48, 0.61, 1.15, 2.52, 3.06, 3.70, 4.30, 9.20, 14.26, and 18.50 wt pct. Nominal

Jan 1, 1958

By L. B. Davidson

The petroleum literature contains many reports on the relative permeability properties of porous media. However, only recently have studies of relative permeability at elevated temperatures been made.1 -5 Each of these studies presents relative permeability data on water-oil systems in linear sandpacks or sandstone cores under isothermal conditions. The results of these investigations are dissimilar. Edmondsonl found that in Berea sandstone a temperature-dependent effect was present, while Shilobod,2 using the same material, found no temperature dependence after normalizing for initial water saturation. Workers at Texas A&M U.3-5 found that the ratio kw/ko was temperature dependent in an unconsolidated system. The differences in results of these studies are probably a consequence of differences in the material employed, in the experimental procedures followed, and in the properties of the porous systems used. This paper describes an experimental investigation of permeability ratio temperature dependence, conducted to clarify some of the results obtained by previous workers. Each experiment described in this paper involved the isothermal displacement of Chevron No. 15 white oil by either nitrogen, steam, or distilled water and displacement of water by nitrogen. All permeability ratios were calculated using the Welge procedure. Values of the water-oil permeability ratio were obtained over the temperature range 75OF to 540°F. Results indicate the ratio is temperature dependent at low water saturations, probably due to interfacial effects. However, as the saturation is increased, temperature dependence decreases until, above some minimum saturation, the ratio becomes insensitive to temperature. Previously published work indicates that the dependence reappears at very high water saturations, a region of the ratio curve not completely examined in the present study. It appears that water-oil permeability ratios are temperature dependent at the extremes of the ratio curve where changes in interfacial tension with temperature induce variations in residual saturations. Between the extremes, there is a region in which the permeability ratio is insensitive to temperature. The size and location of this region is probably a function of the characteristics of the porous system. Gas-oil permeability ratios calculated from nitrogen-white oil displacement experiments indicate a definite temperature dependence over the range 75OF to 500°F and over the entire gas saturation range studied. Evidence discussed in this report indicates that this dependence is a consequence of molecular slippage in the gas phase. This is an extension of the Klinkenberg effect6 to two-phase systems at high temperatures (the existence of slippage in two-phase systems at room temperature has been demonstrated7). Evidence for a similar source of temperature dependence in superheated steam-white oil experiments

Jan 1, 1970

By Salinger, Herbert

WITH the large amount of metallurgical re- search work now being done and the constant effort of the engineer to effect economies of operation, I think it is a safe prediction that the next few years will see a great change in the handling of mine products. The well-managed mine, with sufficient ore reserves to warrant the necessary plants, will increasingly call upon the metallurgist and chemist for the solution of its problems. Shipping sorted ore or concentrate to the nearest smelter will not be the course followed. From ore to metal, or at least to a product directly salable to the consumer, will be the practice followed. As a consequence, mine managers will be increasingly interested in metal trade problems. By metal trade I mean the buying, selling, shipping, handling, and all the practices, forms and customs that go to make up the trade.

Jan 1, 1928

By Charles Will Wright

The present struggle for economic and industrial supremacy by the Communist world is against the United States, its main target, and the other Free World nations. The basis of industrial power is minerals, so the Communist nations are building up mineral production within their borders, often regardless of costs, and are acquiring quantities of mineral products from Free World countries for future use. They are contracting for additional supplies and advancing funds for the development of these quantities. A number of the less developed mineral producing countries of the Free World are being infiltrated by Communists and Communistic influence. This situation is well known, but as yet little has been done to oppose these activities or to awaken the public to their seriousness. The Communist countries are still far behind the Free World Nations in production of many essential minerals. But, shortages are being made up from Free World nations in exchange for petroleum, manganese ore, chromite and other products. Restrictions on shipments of strategic materials to Communist countries have not been maintained.

Jan 1, 1964

By W. A. Scheuch

ORDINARILY secondary copper, unless electrolytically refined, is reclaimed directly as foundry ingots used in the manufacture of copper-rich alloy castings. This use does not require the elimination of the impurities to the degree required if the recovered metal is to be used for electrical purposes where a high electrical conductivity is of prime importance. However, as a part of the general policy of reusing its own scrap and by-products wherever possible, the Western Electric Co. at its Hawthorne Works is recovering its secondary copper as wire bars which are delivered to its own rod and wire mill and there processed into wire of high electrical conductivity. This departure from the usual recovery scheme has been accomplished through the careful classification and sorting of the material entering the furnace charges and the careful control of the subsequent melting and refining in a reverberatory furnace. Tests conducted over a period of approximately four years have shown that the quality of wire bars produced from selected secondary copper is equal to that of wire bars produced by the electrolytic refineries. The interest which has been exhibited in the process by those who have seen it has prompted the following general description. It is the authors&apos; opinion that the recovery of secondary copper will become more and more an important factor in the copper production industry. The description is largely of the refining furnace and its operation, but it must be remembered that careful classification and sorting of the scrap materials to eliminate impurities are just as important as the furnace operation toward obtaining a satisfactory final product. Classification and sorting do not lend themselves easily to description; they must just be done. It should also be recognized at the outset that constant intelligent supervision is requisite to the success of the process because there are so many ways in which impurities can find their way into the final product.

Jan 1, 1929

By F. L. Clerc

THE lead and zinc region of SW. Missouri is interesting, not only by reason of the value of its output, which ranges in the neighborhood of ten million dollars a year, but even more because of the facilities which it offers for the study of certain forms of ore-deposits, of which the loci and genesis are somewhat obscure. Although the mineral species found in the region are few and of common occurrence, crystallization has taken place on a generous scale, and unusual forms abound in many combinations, presenting examples of pseudomorphism, paragenesis, metasomatic replacement and the action of mineral-depositing and mineral-dissolving waters. For the mineralogist, lithologist, and specialist in certain lines of metamorphism, it has peculiar attractions, while the systematic geologist will perhaps find its chief claim to attention in the simplified problem it presents, in the study of ore-deposits. In addition to the phenomena above enumerated, it presents instances of well-developed comb-structure in the ores, fissures and faults, and slickensides-features usually associated with extensive movements in the earth&apos;s crust, and believed by some authorities to prove the deep-seated origin of the ores. In connection with these occurrences, the absence of all igneous rocks from this region is noteworthy and significant. For that reason, the simplified case presented by the Joplin region, from which these rocks have been eliminated as a factor, is specially valuable. Having had unusual opportunities to watch the development of this district, I have been deeply interested in the bearing of the revelations of the Joplin mines upon questions of universal importance to the science of ore-deposits ; and it was to my great regret that the project of a meeting of the American Institute of Mining Engineers at Joplin, proposed in 1892, was

Mar 1, 1907

By W. Hurst

The authors of this paper, in substituting values in a material balance equation associated with a gas reserve and a water drive, cannot find sustainment of what the gas in place should be; therefore, their conclusion is that this type of problem dealing with gas reservoirs is insoluble. They have introduced the word, "cybernetics," based on the work of Norbert Wiener, that further extends this line of reasoning, namely, to the effect that the system is a "black box", and that the gas reservoir and aquifer can take on infinite aspects &apos;based upon their past performance, to quote the authors. The inference is that this black box is an unknown. which permits in computer programming to subscribe as many variables as possible to observe by adjustment of one to another those combinations of conditions that fit field behavior. This may satisfy those in this discipline whose dedication is to programming, but to the others this is a comparison to the rationalization of the combinational results of the throwing of dice—a probability procedure. In reservoir engineering we are more direct. We learn from the examination of individual we&apos;ll and field data exactly what is in this black box. I now come to the impasse that has confronted these authors in their machine calculations. In this I have reproduced from their own production data (Tables 1 and 2 of their paper) pressure vs cumulative gas produced. shown as Figs. D-1 through D-5. A perusal of any of these five plots, for the corresponding fields in the Po Valley, shows the straight-line relation of pressure vs gas produced, evidencing pressure depletion. The point I make is that in their fundamental production data, there is no variance from a straight line that can support a water drive.

By J. C. Bayles

Jan 1, 1886

By S. Saito, P. A. Beck

The crystal structure of MoNi3 was determined by means of X-ray diffraction. This structure is isotype with that of ovgered TiCu3. The lattice parameters are: a. = 5.064A, bo = 4.224A, co = 4.448A, and zf 0.157. If the orthorhombic distortion (slight relative to the corresponding orthohexagonal unit cell) is disregarded, the structure may be described in terms of a close-packed ordered atomic layer, stacked in the sequence: abab. The structztres of ordered TiCu3 and TiAl3 are homotectic. The three types of ordered hexagonal phases, iso-structural with TiNi3, MgCd3, and VCo3, are known to occur in AB3 alloys of transition elements of the first, second, ad third long periods. It was noted1 that phases with the TiNi3 structure occur selectively in alloys of Ti-group elements with Ni-group elements. In AB3 alloys of Ti-group and V-group elements with Co-group elements the AuCu3-type structure predominates.&apos; The vCO3 structure, which was determined very recently,&apos; has hexagonal symmetry, but the actual atomic arrangement here, too, is rather closely related to the ordered cubic structure of AuCu3-type. However, an ordered hexagonal close-packed structure of the MgCd3-type occurs in MOCO33 and WCO3.4 Consequently, the question arises as to whether or not the crystal structure of MoNi3 is also of the MgCd3-type. Grube and winkler5 found that MoNi3 has a hexagonal close-packed structure with a = 2.54A and c/a = 1.65. They pointed out that some additional weak diffraction lines could be observed in the powder pattern, which may have been due to an ordered atomic arrangement in this phase. However, no detailed information was obtained by them and the structure was apparently not further investigated by others. The present work was, therefore, undertaken in an attempt to determine in detail the structure of MoNi3, and to investigate the possibility of ordering. EXPERIMENTAL METHODS Alloys used in the present work were arc-melted in a water-cooled copper crucible under helium atmosphere. Electrolytic nickel and molybdenum, both 99.9 pct pure, were used. Chemical analyses were not made, but the melting loss was not higher than 2 pct for any alloy. Ingots were first homogenized at 1200°C for 48hr, quenched, heavily cold worked, and then annealed at 820" or 860°C for 1 week, followed by quenching in cold water. Powder specimens for X-ray work were prepared by crushing the heat-treated solid specimens. In order to remove strains, the powders were reannealed in evacuated scaled fused silica capsules for 6 hr at the same temperature at which the corresponding solid specimens were annealed. X-ray photographs were taken with an asymmetric focussing camera, using unfiltered CrK or CuK radiation. EXPERIMENTAL RESULTS The X-ray diffraction patterns of alloys containing 20.8, 25, and 26.4 at. pct Mo, homogenized at 1200°C, showed the face-centered-cubic structure of the Ni-base a-solid solution. It was revealed, however, by micrographic examination that the 26.4 at. pct Mo alloy contained in addition very small amounts of a second phase, in accordance with the phase diagram.6 On the other hand, the 20.8 at. pct Mo alloy after annealing at 820°C gave the X-ray diffraction pattern of the ordered face-centered-tetragonal MONi4.7 In this pattern several additional weak diffraction lines were also observed, corresponding to the strongest diffraction lines of MoNi3. The alloys containing 25 and 26.4 at. pct Mo after annealing at 820" or 860°C gave X-ray diffraction patterns, as shown in Tables I and 11, corresponding to MoNi3. Each one of the reflections which could be tentatively indexed on the hexagonal close-packed cell of Grube and Winkler,5 with the exception of the basal plane reflections, was split into a doublet, as seen in Table I. Since microscopically the alloy consisted of a single phase, it seemed probable that the lattice of MoNi3 is actually slightly deformed, as compared with the tentative hexagonal unit cell. In addition to these diffraction lines, several weak lines were also present, as shown in Table 11, which could not be indexed at all on the hexagonal close-packed cell considered. Satisfactory indexing of all diffraction lines observed was found to be possible by using an orthorhombic unit cell with ao = 5.064A, ft = 4.224A, and c = 4.448A. These values, whose accuracy is estimated to approximately ± 0.008A, correspond to 95.14A3 for the volume of the unit cell, and to an X-ray density of 9.50 g per cm3. If no attention were paid to the weak reflections listed in Table II, a reduced -unit cell of half the volume (a = 2.532A, b = 4.448A, and c = 4.224A), closely related to the orthohexagonal cell, might be used. The dimensions of the orthohexagonal cell of the same volume as the reduced cell are: a = 2.562A, b = 4.437 A, and c = 4.183A. It may be seen that in the reduced cell the a axis is slightly shorter, while the b and c axes are slightly longer than those corresponding to the orthohexagonal cell of the same volume. This slight orthorhombic distortion is re-

Jan 1, 1960

By J. W. Mills

In 1956 the discovery of nickel on Jumbo Mountain, Snohomish County, Washington, focused attention on this part of the Cascade Range, far more renowned for its timber than for its mineral resources. Hand specimens assaying as high as 13 pct Ni encouraged Discovery Mines Inc. of Mount Vernon, Wash., to stake 12 claims in Township 31 North, Range 9 East of the Willamette Meridian. The property was leased to Climax Molybdenum Co. in January 1957. Trenching, sampling, and geologic studies were carried out during the late summer of 1957 when most of the snow had disappeared. Although the deposits are only about four miles south of the logging town of Darrington and about two miles. as the crow flies, southeast of the end of a good gravel road from that town, all camp supplies and equipment were air-dropped, owing to the extremely rugged nature of the terrain. GEOLOGY The rocks of Jumbo Mountain comprise a series of folded Tertiary sediments forming a belt one half to three quarters of a mile wide, trending northwest about parallel to the strike of the beds. This belt is sandwiched between two extensive in-trusives—gabbro on the northeast and quartz dio-rite on the southwest—and has been intruded by dikes of fresh and serpentinized dunite. Shear zones follow many of the dunite-sedimentary rock contacts, and in these the nickel mineralization is concentrated. A few transverse faults offset the sediments and ultrabasics. Sedimentary Rocks: Two kinds of quartzite make up the greater part of the sedimentary section. One is dark purplish gray, very fine-grained, and thin-bedded; the other is light gray to white, medium-grained, and well-bedded. Locally the light-colored quart lites contain grit and conglomerate horizons, rich in pebbles of white chert and very fine-grained quartzite. Intercalations of dark argillites near the summit of the mountain give many of the cliffs a striking banded appearance. Dark gray to black, aphanitic, thin-bedded argillites occur throughout the entire sedimentary belt. Beds vary from a few inches to a few tens of feet thick and some, near the summit, contain numerous fossile (willow?) leaves. Only the thicker beds were mapped. The sediments are quite fresh on the northeastern side of the belt and become more metamorphosed (hornfelsed) toward the southwestern side. Brown biotite is present in the metasediments in increasing amounts as the quartz diorite is approached. Near the intrusion, porphyroblasts of plagioclase, up to 1 in. across, testify to the soaking of sedimentary rocks by solutions emanating from the quartz diorite. Most of the sediments mapped lie along the southwestern limb of an anticline, the axis of which follows the crest of the mountain and plunges at a low angle to the northwest.

Jan 1, 1961

By P. Sanchez-Mejorada

GEOLOGISTS who are acquainted with the mines of northeastern Mexico realize that the most important lead-silver replacement deposits of the province are confined to a single formation. But since the formation is several hundred meters thick, the author has determined the relative position of the lead mantos in the belief that this information will prove useful in the search for new mines. This article describes the stratigraphic location of lead-silver replacement deposits known in several mines situated in a region comprising part of the states of Coahuila and Nuevo Leon. The area studied extends for 200 km* (125 miles) from east to west and 70 km (45 miles) north to south. Metallogenic Province: The most important metallic deposits of the region have the following common characteristics: 1) The orebodies occur as manto replacements of calcareous sediments. 2) The horizons that have contributed large tonnages of ore are in similar positions in the corresponding stratigraphic columns (as it will be shown later on). 3) Lead is the most important metal in the ores. Silver is commonly present in small amounts. Occurrence of zinc is dependent on the degree of oxidation of the primary sulfides. 4) A large proportion of the total production has been in the form of oxidized ores. 5) The deposits are located on anticlines. Rocks of Cretaceous age crop out over large areas of the states of Nuevo Leon and Coahuila. forming part of a belt that extends to the south along the eastern Sierra Madre. The sediments are cut by a small number of intrusive stocks ranging in characteristics from rhyolite to diorite. The most prominent structural feature of the region is a series of folds trending northwest-southeast. Faulting is not conspicuous in the region, although a major fault zone is found farther East.&apos; The physiography closely reflects structural features, with mountains formed by anticlines and valleys conforming with intermediate synclines. Narrow valleys have also been developed along the axes of many anticlines, where solution of limy sedi- ments and erosion have proceeded along axial tension fractures. Stratigraphy: Rocks of the Upper Cretaceous are exposed in only a small percentage of the total area. Generally they have been eroded away from the mountains and are covered by recent talus and alluvium in the valleys. Humphrey&apos; has published an excellent paper describing the Cretaceous formations of the Sierra de los Muertos, a short distance west of Monterrey. A brief summary of these formations is given below to convey an overall picture of the stratigraphic sequence that prevails just south of the area under consideration. Upper Cretaceous Indidura: Essentially thin shaly sediments. Cuesta del Cura: Limestone in thin wavy beds

Jan 1, 1959

Jan 1, 1965

THE hall of the Western Iron and Nail Associations having kindly been placed at the service of the Institute, the opening session was held at 3 o&apos;clock, Tuesday afternoon, May 13th, with an attendance of about one hundred and twenty-five members. Mr. William Metcalf, of Pittsburgh, read an address of welcome on behalf of the Local Committee of Arrangements, to which President E. B. Coxe responded. The following papers were then read and discussed : Regenerative Stoves; a Sketch of their History and Notes on their Use, by John M. Hartman, of Philadelphia. Some Curious Phenomena Observed on Making a Test of a Piece of Bessemer Steel, by William Kent, of Pittsburgh. On the Use of Determining Slag Densities in Smelting, by Thomas Macfarlane, of Wyandotte, Michigan. After the reading of these papers each member was presented by the Local Committee with a schedule of excursions, a specially prepared map of Pittsburgh and surroundings, and a directory of industrial works, all tastefully bound, and also with a metal badge bearing the seal of the Institute, to be worn on the excursions. The second session was held on Tuesday evening. The following persons, duly proposed for members and associates of the Institute, were, on the recommendation of the Council, unan¬imously elected. (In this list are included those elected at the final session on Friday morning.) George Bartol, - Cleveland, Ohio. Luther S. Bent, - Steelton, Dauphin Co., Pa. Octave Chanute, - New York City. Albert H. Childs, - Allegheny, Pa. Theodore Cooper, - New York City. Andrew Cosgriff, - Brewster, Putnam Co., N. Y. William B. Crocker, - New York City. Henry M. Curry, - Pittsburgh, Pa. Charles Davis, - Allegheny, Pa. Henry F. De Bardeleben, - Birmingham, Ala. Herbert Du Puy, - Pittsburgh, Pa. Charles L. Fitzhugh, - Pittsburgh, Pa. W. S. Franklin, - Ashland, Md. F. G. Fricke, - Pittsburgh, Pa. Paul A. Fusz, - St. Louis, Mo. Ignatius Hahn, . Pittsburgh, Pa. Henry Hargreaves, - South Pittsburgh, Tenn.

Jan 1, 1880

By John Nunes, Frank R. Larson

Temperature-dependent functions of various ten-sile flour stress and fracture parameters were investigated on iron and low composition alloys of Fe-C, Fe-Cr, Fe-Mn, and Fe-Ni. Data were obtained over a range of test temperatures from 200" to -196"C at an initial strain rate of 0.01 min". It was found that the strain-hardening exponent, n, for the Fe-Ni alloys increased significantly at very low testing temperatures with increased alloy addition. Also, the stress and strain at fracture followed a predictable transitional type of behavior. The flour stress-temperature dependence was evaluated employing the relation: M where it is shown that composition can strongly influence the constant M. An empirical formula describing this effect is as follows: M = MI (equivalent at. pct Ni)-&apos;" Some preliminay, tests were run on several commercial steels to test the generality of this relationship. One of the phenomenological explanations of the ductile-to-brittle transition encountered in bcc metals is based upon the difference in the temperature dependence of the flow and fracture stresses.&apos; It states simply that the fracture stress is relatively insensitive to temperature and that the yield or flow stress rises rapidly with decreasing temperature so that, when the flow stress reaches the fracture stress, brittle fracture occurs without appreciable plastic deformation. This behavior is illustrated schematically in Fig. 1 where the ductile-to-brittle transition is shown to occur at two possible temperatures. The lowest temperature, TB, represents essentially completely brittle behavior while the higher temperature, TN, represents "notch" brittle behavior. Support for this theory is obtained when it is observed that fcc metals, which do not commonly have a ductile-to-brittle transition, also do not commonly exhibit any strong temperature de- pendence of the yield stress. This relationship of yield or flow stress behavior with the ductile-to-brittle transition has been generally observed for most metals representative of these two crystallo-graphic structures. One exception to this generalization appears in the case of tantalum where no apparent ductile-to-brittle transition has been observed. However, this may simply be an indication that this type of behavior is not directly related to the flow stress and that some other mechanism such as twinning must also be operative. A comparison of the typical temperature dependence of the yield stress of some representative metals is shown in Fig. 2. In the study of the temperature dependence of the strength of metallic materials, considerable ef-

Jan 1, 1963

By AIME AIME

THE annual meeting of the Woman&apos;s Auxiliary to the A.I. M.E. is always held in New York, in con- junction with the annual meeting of the Institute in February. Business sessions, teas, dances, a theater party, luncheons, excursions, and many other interesting activities filled the four days to overflowing. In all ,216 women were present, from all parts of the United ,/ mates, and there were several from Canada. On Mon- &apos; day not only the visitors, but the New York members also, gathered around the registration desks, where Mrs. E. N. Wolfes, Mrs. S. J. Jennings, and Miss Georgene Davis saw that everyone was properly registered and provided with tickets to whatever functions she desired to attend. Greetings were eagerly ex- changed as friends met at the luncheon on the fifth floor, where the hostesses of the day were Mrs. J. D. Handy, Mrs. T. T. Read, Mrs. Sidney Rolle and Mrs. H. J. Wolf. In the afternoon, there were visits to art galleries and other interesting exhibits, arranged by Mrs. Frederick Laist. Mrs. W. H. Bassett was the hostess at a very delightful Thé damant at the Italian Gardens of the Ambassador Hotel. Many of the men attended this function also. In the evening the visiting ladies were entertained at a theater party, with Mrs. Wilbur Judson as hostess. The play that was seen was Gorki&apos;s "At. the Bottom."

Jan 1, 1930

Map

Jan 1, 1941

By J. E. House, C. J. Lewis

In the solvent extraction process, also referred to as liquid-liquid extraction, the clarified uranium-pregnant sulfuric acid leach solution is contacted with an organic extractant dispersed in kerosene; the uranium enters the organic phase and associates itself with the organic extractants. Simultaneously an-ions or cations, as the case may be, leave the organic extractant phase and enter the aqueous phase. The two phases are then allowed to separate by virtue of their immiscibility. Based on the data available, a generalized procedure for the recovery of molybdenum from the sodium carbonate scrub liquor of acid leach uranium mills using secondary and tertiary amine extractants is presented, as is another generalized procedure for the recovery of molybdenum from the bleed stream of alkaline leach uranium mill circuits. Such economic appraisal as can be made at this stage of the development is also indicated. Molybdenum occurs in most uranium ores. Whether the uranium is solubilized by the acid leach route or by the alkaline leach process, some of the molybdenum present in the ore is solubilized along with the uranium. Molybdenum in uranium mill pregant solutions may cause processing difficulties, among which may be mentioned the poisoning of resins, the precipitation of organo-molybdenum complexes, or the build-up of molybdenum in recycle streams. While the uranium milling industry has been successful in applying measures to overcome the problems arising from the presence of molybdenum in the circuits, such measures nevertheless add to the cost of producing uranium yellow cake concentrate. Table I shows the analysis of typical uranium pregnant leach solutions. Uranium recovery by solvent extraction is presently practiced only in conjunction with acid leach circuits, and it may be noted that of about 16,000 tons of uranium ore daily processed by sulfuric acid leach, more than half of this tonnage follows the solvent extraction route. Uranium mills leaching ore with sodium carbonate-sodium bicarbonate solution (the so-called alkaline leach circuit) do not use solvent extraction. In this case the uranium pregnant solution is sufficiently pure to permit the direct precipitation of uranium concentrate with subsequent recycle of the alkaline leach solution. While solvent extraction procedures may be developed which are economically attractive for the alkaline leach uranium process, this has so far not been the case. The earlier uranium mill solvent extraction circuits used organo-phosphate extraction reagents, among which di-2-ethylhexyl phosphoric acid was popular. It should be borne in mind that uranium in its sulfuric acid leach solution exists in an equilibrium involving uranium in both anion and cation forms: uo + 2S0 = [uo2(so4)2] For this reason uranium may be extracted by either cation extractors or anion extractors and this is likewise true of molybdenum. However, the organo-phosphate extractants also load ferric iron which is usually present in the uranium acid leach solution. For this reason, it is necessary to reduce this solution substantially to the ferrous state ahead of solvent extraction using organo-phosphate reagents. The amines, being anion extractors, selectively reject iron and thus render the iron reduction step unnecessary. In the solvent extraction process, also referred to as liquid-liquid extraction, the clarified uranium-

Jan 1, 1961

By Eugene McAuliffe

AS anthracite is no longer used to a marked extent by the rail- ways of the United States (1,513,000 tons in 1933), that portion of the mining industry engaged in the production of bituminous coal is, and will continue to be, the one chiefly concerned with the future use of its product by the railways. In a period such as the present, when all enter- prise is unsettled, when fundamental principles of industrial management and control are being swept aside or else changed overnight, it is difficult to predict what will happen. The relation between the total production of bituminous coal and the volume consumed by the steam rail- ways of the United States, Classes I,

Jan 1, 1936

By H. A. Domian, H. Biloni, G. F. Bolling

Jan 1, 1965

By ALFRED T. BARR

In certain areas of the New Cornelia pit, considerable secondary blasting is necessary to reduce oversized boulders, formed from primary blasting, to pieces which will pass the 41/2-cu yd dippers on the shovels. Some of the boulders are &apos;dobied, but when time permits they are blockholed and blasted. In most instances one hole drilled to a depth of 2 to 3 ft and blasted with 1/3 to 1/2 of a stick of powder will break a boulder satisfactorily. Blockholing is normally done by using a jackhammer of the 55-lb class, 1-in. round drill steel, and detachable steel bits, 2-in. gauge when new. A bit change is usually made after the completion of each hole. The use of light drilling equipment in blockholing is desirable, both from the standpoint of safety and ease of doing the work, and when it was seen there was a possibility of using a lighter jackhammer through the use of tungsten-carbide bits and at the same time get at least the same drilling efficiency as with the standard equipment, it was decided to test tungsten-carbide bits. The claims for long life of the bits and footage drilled before resharpening gave hopes of eliminating much of the delay time in changing bits which is unavoidable with the use of steel bits. and thus gain in actual drilling time.

Jan 1, 1949