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By E. A. Cisney

The formula for calculating the crystallographic angles of a tetragonal lattice is: C°S =where $ is the angle between planes (HKL) and (hkl). The angles in Table I have been calculated for indium

Jan 1, 1960

Three. meetings for the presentation and discussion of papers were held in 1914, as follows: The 107th Meeting, including the Annual Business Meeting, in New York, Feb. 16 to 19; the 108th Meeting, Aug. 10 to 14, in Salt Lake City, and the 109th Meeting, Oct. 8 to 10, in Pittsburgh, Pa., under the auspices of Iron and Steel Committee, Committee on Coal and Coke, Committee on Petroleum and Gas, Committee on Non-Metallic Minerals. Local Sections ' Three new local sections were established during the year, namely; / Pennsylvania Anthracite Section, Chicago Section, and Utah Section.

Jan 1, 1917

By B. H. Cody

THE Morenci concentrator of the Phelps Dodge Corporation is a part of the project that was completed after five years had been spent in development of the open-pit mine, equipment and process testing in the former No. 6 concentrator, and construction of the reduction works. The reduction works, of which the concentrator is a part, is about a mile and a quarter southeast of Morenci, on the highway that leads up Morenci Canyon. The concentrator has a nominal capacity for the treatment of 45,000 tons of ore daily. The original plant, which has a rated capacity of 25,000 tons of ore daily and is now in its fifth year of operation, began production on Jan. 30, 1942. The addition, to increase the capacity 8o pct, began operation on Dec. 1, 1943. The equipment of the original plant has been described in MINING AND METALLURGY (May 1942). No changes in equipment were recommended for installation in the concentrator extension and only one major change, forced by a shortage of maintenance labor, has since been made. Metallurgical treatment has been altered in some ways as experiments progressed and as labor and economic conditions dictated. No complete description of the operation of the concentrator has been published, so this paper will record such operating and equipment changes as have been necessary, the operating methods that have been developed and the metallurgical results that have been obtained. Descriptions are given in the order of the processes with a flowsheet and an equipment list of each process for convenient reference. The questions asked by engineer visitors have guided the detail in which operation and maintenance are described. During the period Jan. 30, 1942 to Sept. 1, 1946, ore milled has totaled 43,595,253 dry tons, from which 1,643,885 tons of concentrate have been made, containing an indicated production of 783,164,809 lb of copper. The principal results obtained in operation of the concentrator during the years 1942 to 1945, inclusive, and to Sept. 1, 1946 are shown in Table 1. A graphic general flowsheet of the plant is given in Fig I. ORE The Morenci ore that is now being treated is a medium-hard monzonite porphyry in which the principal sulphide minerals are chalcocite and pyrite. A minor amount of covellite is present. Chalcopyrite and bornite have been observed under the microscope. The chalcocite occurs mainly as a coating on pyrite. Some of the coatings are so thick that the pyrite presents the appearance of being an inclusion in chalcocite. Some are less than one micron thick and are barely visible at 500 diameters magnification of a polished cross section. Some chalcocite is present as a dissemination in the gangue. Various oxidized copper minerals are present as a result of oxidation in place but they represent a minor proportion of the copper minerals of the ore body. Oxidation

Jan 1, 1947

By C. W. Merrill

The price records of seven representative mineral commodities for the 68-year period 1890 through 1957 have been compiled and analyzed for significant trends. When these records are reduced to real prices in terms of dollars of constant purchasing power or to the purchasing power of industrial wages at average rates, a substantial overall fall in prices is revealed. This downtrend contradicts the widely held concept that heavy drafts on a mineral resource must lead to scarcity, reflected in rising prices. Three metals (aluminum, copper, and pig iron), two fuels (bituminous coal and petroleum), and two nonmetals (sulfur and cement) have been chosen because of their pre-eminence in their respective categories, their significance in an industrial economy, and the ready availability of their price records. It might be added that these seven commodities were selected before any price figures were compiled; none was selected or rejected to substantiate any preconceived notions as to price trends. The overall importance of the seven is demonstrated by the fact that, taken together, they composed over three-fourths of the value of all minerals produced in the U. S. in 1957. The first step in the analysis was to reduce the price records to a basis for significant comparisons. Two such comparisons have been made: 1) The quantities of each of the commodities that could have been purchased for an average hour's wage in each year, and 2) the unit price of each commodity through the years in terms of deflated dollars. These data are set forth in the accompanying table and two charts. The quantities of the mineral commodity purchasable with the average wage for one hour's work in all manufacturing industries through 1926 were based on annual average prices and on average annual wage rates determined by Paul H. Douglas and published in his "Real Wages in the United States, 1890-1926." The series was extended through 1957 by the Bureau of Labor Statistics, U. S. Department of Labor. Calculations based on these data show that the average worker could have purchased 1.28 lb of copper with his hourly wage in 1890, whereas his hourly wage would have purchased 8.11 lb in 1957, an increase of 633 pct in the 68-year period. An average hour's wage would have bought 10.85 gal of petroleum in 1890, compared with 33.04 gal in 1957. Even more spectacular is the increase in sulfur, of which 25.25 lb could have been purchased with the 1904 average hourly wage; 223.08 lb were purchasable with the wage in 1957—an increase of 883 pct. Comparable price data for sulfur are not available for years earlier than 1904. For every commodity, the calculations show an improvement in the wage earner's purchasing power in 1957 compared with the early years. Measuring purchasing power in terms of wages does not give an entirely fair picture of the availability of a commodity in an economy. When the efficiency of an economy changes and the balance shifts among such elements as raw-material production, manufacturing, and service trade, the economic significance of an hour's work changes. Partly to meet such criticism, but mostly to present another interesting measure of the response of minerals to changing market conditions, a second set of calculations has been made to deflate unit prices for the seven commodities into terms of 1954 dollars. To accomplish this adjustment to a common 1954 parity, the Gross National Product Price Deflator, developed by the Office of Business Economics, U. S. Department of Commerce, was used. Although the results of these calculations are not as striking as those based on labor's increasing purchasing power, nevertheless the declines outweigh the rises in the prices of the mineral commodities. In terms of these deflated prices, aluminum and sulfur are much cheaper today than in the early years; copper was substantially cheaper in 1957 than in 1890; pig iron and petroleum are little changed; and only bituminous coal and cement have increased substantially. Strangely, the two mineral commodities with the strongest reserve positions are the two to exhibit rising real prices. Now this apparent overall downtrend in prices has taken place during a period of almost fantastic increase in the demand for mineral products. The value of minerals consumed in the world during the period greatly exceeds all mineral consumption up to 1890. A stage has been reached in the U.S. in which 95 pct of the energy used is of mineral origin and in which machines, structures, roadways, communication facilities, and most other elements in the industrial economy are primarily of mineral origin. Even agricultural fertility is maintained, in large measure, by mineral fertilizers. A series published in Minerals Yearbook shows that the value of U. S. mineral products has risen from $615 million in 1890 to $18,000 million in 1957, a 29-fold increase. Even in deflated dollars, the increase has been eightfold, while population has expanded less than threefold. Not only are demands of the industrial nations— the U. S., countries of Western Europe, and Japan— increasing at rapid rates, but those countries with agrarian economies are calling themselves underdeveloped and clamoring to industrialize. The ever-expanding mineral requirements in the U. S. and throughout the world show no abatement. Mineral reserves frequently have been described as wasting assets. Much concern has been shown for future users, who have been pictured as finding themselves on a plundered planet. Conservationists have viewed the future with alarm and have demanded legislation and regulations to reduce the drain on mineral reserves.

Jan 1, 1960

By J. Suiter, H. F. Ryan

H. F. Ryan and J. Suiter (CSIRO)—In this paper the authors have presented "a physical model which has as its central hypothesis the solution strengthening of regions along grain boundaries in the order of tens of angstroms thick", and their calculations have used 40Å as the zhalf-width of this boundary region. Selection of this value by the authors suggests that they were unaware of a number of recent field-ion microscope observations of grain boundary structures (e.g., Refs. 29 and 30). The accompanying figure, Fig. 9, shows a portion of an ion micrograph of a tungsten specimen containing a grain boundary, and the regular arrangement of atoms in various crystal planes in each grain can be seen, except in the boundary zone which is not more than two atom diameters in width. Since it is expected that solute atoms will segregate only to the region where the lattice is disturbed, it would seem that a value of 4Å for the half-width of the boundary region would be more appropriate than the value of 40Å assumed by the authors. If the former value is used in Eq. [8] of their paper to obtain curves showing solute concentration in the grain boundary as a function of temperature, the resulting curves differ significantly from those obtained by the authors. Although there are only relatively slight changes in the regions corresponding to higher temperatures (i.e., grain boundary concentrations of approximately 1 at. pet), at lower temperatures the curves are no longer realistic. For example, the curve corresponding to u = 7000 cal per mole gives a solute grain boundary concentration in excess of 100 pet at a temperature of approximately 360°K, and "flattens out" at a grain boundary concentration of about 300 pet! Similar results are obtained with each of the other curves. Ion microscopy of dilute solid-solution alloys has shown that solute atoms give rise to image points which in most cases are of higher intensity than those of the solvent atoms.31 If the same behavior occurs when the solute atoms are present in much lower concentrations then ion microscopy should provide a sensitive tool for studying the segregation of impurities to the grain boundary regions. Although many grain boundaries in tungsten have been examined after different thermal and mechanical treatments, there has not been, as yet, any systematic study of such segregation. In general the micrographs show no clear indications of marked grain boundary segregation, but occasionally areas are found where the grain boundary contains an appreciable number of image points of high intensity in a very narrow zone, see Fig. 9. If it is assumed that these correspond to impurity atoms then it is possible to estimate the impurity concentration both in the grain boundary and within the body of the grains. Application of this method (to a larger area

Jan 1, 1965

By R. V. Whetsel, V. R. Gargias, J. W. Ristori

WoRld consumption of petroleum and its substitutes in 1941, the amount of which obviously is largely conjectural, is estimated at 2,066,653,000 bbl. This is 48,689,000 bbl. more than the previous year and is an all-time high. Except for the United States, this figure does not include consumption for military purposes. Consumption in the United States also reached an all-time high during 1941, totaling 1,492,000,000 bbl., or 158,230,000 bbl. more than the previous peak year of 1940. On the other hand, it is estimated that civil consumption in countries outside of the United States decreased 109,541,ooo bbl. as compared with the previous year. Demand for military purposes and/or additions to stocks in countries outside of the United States is estimated at 304,507,000 bbl. during 1941, compared with 209,635,000 bbl. in 1940. This increase was due largely to blitzkrieg warfare on several fronts. especially Russia; entailing large expenditures of petroleum by both sides because of the immense area covered by the fighting forces, the long supply lines necessary and the intensity of the fighting. It is interesting to note in this connection that Axis-controlled countries, excluding Japan, had an estimated production of approximately 89,000,000 bbl. of petroleum and its substitutes in 1941. The peacetime consumption of these countries in 1938, for example, was about 183,000,000 bbl. It is believed that the minimum to which civil consumption could possibly be re-duced in wartime is 20 per cent of that of peacetime, which would call for a minimum consumption of 37,000,000 bbl. in these countries in 1941 for civil purposes. This

Jan 1, 1942

By V. R. Gargias, J. W. Ristori, R. V. Whetsel

WoRld consumption of petroleum and its substitutes in 1941, the amount of which obviously is largely conjectural, is estimated at 2,066,653,000 bbl. This is 48,689,000 bbl. more than the previous year and is an all-time high. Except for the United States, this figure does not include consumption for military purposes. Consumption in the United States also reached an all-time high during 1941, totaling 1,492,000,000 bbl., or 158,230,000 bbl. more than the previous peak year of 1940. On the other hand, it is estimated that civil consumption in countries outside of the United States decreased 109,541,ooo bbl. as compared with the previous year. Demand for military purposes and/or additions to stocks in countries outside of the United States is estimated at 304,507,000 bbl. during 1941, compared with 209,635,000 bbl. in 1940. This increase was due largely to blitzkrieg warfare on several fronts. especially Russia; entailing large expenditures of petroleum by both sides because of the immense area covered by the fighting forces, the long supply lines necessary and the intensity of the fighting. It is interesting to note in this connection that Axis-controlled countries, excluding Japan, had an estimated production of approximately 89,000,000 bbl. of petroleum and its substitutes in 1941. The peacetime consumption of these countries in 1938, for example, was about 183,000,000 bbl. It is believed that the minimum to which civil consumption could possibly be re-duced in wartime is 20 per cent of that of peacetime, which would call for a minimum consumption of 37,000,000 bbl. in these countries in 1941 for civil purposes. This

Jan 1, 1942

COLUMBIA SECTION S. S. FOWLER, Chairman., J. C. HAAS, Vice-chairman, LYNDON K. ARMSTRONG, Secretary-Treasurer, 720 Peyton Bldg., Spokane, Wash. W. H. LINNEY. J. F. MCCARTHY. On July 15, 16, and 17, 1918, through the good offices of Secretary Stoughton, and the courtesy of War Department officials, Columbia Section was able to secure a series of moving pictures which were presented under the auspices of the Spokane Engineering and Technical Association.. The title was "The Way Out," representing the activities of individuals who had lost an arm, a leg, or both, yet whose apparent misfortunes were made the stepping stones to advancement in various human activities. The exhibitions were given at Natatorium Park in the evening, each of the three performances being attended by 1000 per-sons. Later the films were shipped to Kellogg, Idaho, where they were shown in the principal playhouse one evening to a full house. On July 31, 1918, the Columbia Section participated in the luncheon and other entertainment in honor of Alfred D. Flinn, Secretary of the Engineering Council, who made a trip through the country to meet different classes of engineers, members of the National Societies, for whom he had a message. The entertainment was under the auspices of the Spokane Engineering and Technical Association, Mr. Peter Mogensen presiding. The luncheon was held in the Elizabethan Room, Davenport Hotel, at noon, 35 engineers being present, of whom about one-third were our members.

Jan 9, 1918

Without having asked for it, the writer has apparently been drawn into the discussion regarding relative hoisting capacities which was started by Woodward Iron, egged on by Joe Haller of Cleveland-Cliffs [Mining Engineering, August p. 642] and Axel Kjelgaard [November p. 919], who took exception to Mr. Haller's remarks of tonnage hoisted and avers that they do better in Sweden. It does not appear to the writer that Mr. Haller was inclined to refer to the tonnage hoisted at Cleveland-Cliffs in a manner to imply that they claimed any hoisting record, but rather as a statement that they had hoisted a certain amount of ore during the year 1950. Mr. Haller has been in the mining game long enough to appreciate what Mr. Kjelgaard did not apparently take into consideration, that length of haul, shifts hoisted, nature of ore, method of loading and the many other factors which influence the hoisting cycle make a comparison of tonnages hoisted of two given mines almost an impossibility. Mr. Cheyette sent you .a copy of his letter to Bob Manegold relative to the capacities of the Orient #2 mine. There are several mines around the Country which constantly set up records about which little or nothing at all is ever heard. We cite the Snow Hill Coal Co. mine at Terre Haute, Ind., which has an automatic Nordberg hoist and which hoists 12 tons per trip or 700 tons per hr from 700 ft. This is a counter-weighted installation and a complete cycle is made every 62 seconds or 58 trips per hr. Another mine, The Potash Company of America mine at Carlsbad, N. Mex., has a Nordberg automatic hoist, hoisting eight tons per trip from 1150 ft on a one minute cycle. The materials hoisted in these two mines are ideal for automatic hoisting-they are free flowing so that no hang up is anticipated and hoisting is continuous. Multiplying out the above figures you will find that it is possible to hoist 11,000 tons in two shifts at Snow Hill or over 3 million tons in 300 days per year and over 2 million tons at Potash. Other mines have records which can be pointed to with pride. When a record for one year is established, it doesn't stand too long as here in America the ambition of all the men connected with the operation forces them on to larger tonnages. T. C. WIEDENHOEFER MANAGER MINE HOIST DEPARTMENT NORDBERG MANUFACTNRING CO. MILWAUKEE, WIS.

Jan 1, 1952

By G. Carman Ridland

IN conjunction with a geological investigation of the silver-bearing veins at Contact Lake, Northwest Territories, Canada, a survey was made with a Geiger-Müller counter of the gamma-ray emissions from the rocks in the vicinity of the mine workings. Discontinuous pitchblende veins have been encountered occasionally in the silver-bearing fissures, and the geophysical survey was undertaken with the hope that abnormally high gamma-ray intensities, if detected, might lead to larger and more continuous pitchblende discoveries. Before the instrument was used at. Contact Lake, preliminary tests were made, first with laboratory specimens at Princeton University, and later over known pitchblende deposits at the Eldorado property, LaBine Point, N.W.T. The Geiger-Müller counter, as adapted for field use, is described; the technique of transporting and operating the instrument is outlined; and the general precautions to be observed are discussed. The results obtained at Great Bear Lake show that the instrument is capable of detecting not only a pitchblende ore shoot in a shear zone, but also the mildly radioactive "host rock" at a considerable distance from the ore body. Hence, use of the Geiger-Müller counter is urged, not just for the detailed search for an ore body in a shear zone, but for the detection of possible radioactive "host rocks" in large-scale reconnaissance surveys of unexplored regions made by prospectors and members of federal geological survey parties.

Jan 1, 1944

By William E. Ford, Edward Salisbury Dana

1. THE SCIENCE OF MINERALOGY treats of those inorganic species called minerals, which together in rock masses or in isolated form make up the material of the crust of the earth, and of other bodies in the universe so far as it is possible to study them in the form of meteorites. 2. Definition of a Mineral. - A Mineral is a body produced by the proc¬esses of inorganic nature, having a definite chemical composition and, if formed under favorable conditions, a certain characteristic molecular structure which is exhibited in its crystalline form and other physical properties. This definition calls for some further explanation. First of all, a mineral must be a homogeneous substance, even when minutely examined by the microscope; further, it must have a definite chemical composition, capable of being expressed by a chemical formula. Thus, much basalt appears to be homogeneous to the eye, but when examined under the microscope . in thin sections it is seen to be made up of different substances, each having characters of its own. Again, obsidian, or volcanic glass, though it may be essentially homogeneous, has not a definite composition corresponding to a specific chemical formula, and is hence classed as a rock, not as a mineral species. Further, several substances, as tachylyte, hyalome¬lane, etc., which at one time passed as minerals, have been relegated to petrology, because it has been shown that they are only local forms of basalt, retaining an apparently homogeneous form due to rapid cooling. Again, a mineral has in all cases a definite molecular structure, unless the conditions of formation have been such as to prevent this, which is rarely true. This molecular structure, as will be shown later, manifests itself in the physical characters and especially in the external crystalline form.

Jan 1, 1922

By Ralph H. Sweetser

OF SPECIAL importance in the design and construction of an iron blast-furnace plant are tile raw materials to be employed. Obviously the iron must come from some ore of that metal, but the many kinds available lead to important differences in plant arrangement, and in the design of furnaces and accessory equipment. For instance, the bulk of the gangue in the ore is subject to wide variation as is that of the ash in the fuel. A gradual increase in the bulk of raw material necessary to produce a ton of pig iron has been noted, but this has been more than offset, so far as costs of operation are concerned, by improvements in the machinery used for handling large quantities of ore. coal limestone, and slag. The mechanization of coal and iron-ore mining. the building of big ore boats and limestone carriers, of ore docks for fast loading and unloading, and the general use of heavy railroad equipment have all contributed to greatly reducing the number of man- hours required to mine, transport, and manufacture the raw materials into a ton of pig iron. This looks like a big saving and it is. If it were not for these big labor saving machines it would be impossible to produce the tonnage of iron and steel that is made each year in this country. On the other hand, the total capital investment necessary to bring down the man-hours per ton of pig iron to a 2.3 hours average at the blast furnace and to a total of only 12 man-hours from ore to metal (see Table 1) is so great that even the present high price of pig iron is probably not far above the true cost of manufacture when all the fixed charges are properly included.

Jan 1, 1939

By R. J. Charles

SEARCH for a consistent theory to explain the relationship between energy input and size reduction in a comminution process has accumulated, over the years, an enormous amount of plant and laboratory data. Although some correlation of these data has been possible for purposes of engineering design and for the advancement of research in fracture, there is still great need of a means of predicting behaviour of a solid when it is reduced in size by mechanical forces. The best known hypotheses proposed to describe the energy-size reduction relationships in crushing and grinding stem from a common origin. The present article analyzes problems of comminution in the light of the precepts of this origin. Its object is to reconcile points of difference between these well known hypotheses and to present relationships more widely applicable to comminution studies. Theoretical Considerations: Most existing relationships between energy and size reduction of a brittle solid stem from a single, simple, empirical proposition.&apos; Although this proposition can be demonstrated by observation and experiment, no theoretical derivation is yet possible. Mathematically, the proposition may be stated as follows: dE = -Cdx/xn [1] where dE = infinitesimal energy change, C = a constant, dx = infinitesimal size change, x = object size, and n = a constant. Eq. 1 states that the energy required to make a small change in the size of an object is proportional to the size change and inversely proportional to the object size to some power n. No stipulations are placed on the exponent n in either magnitude or sign. In 1867 Rittinger2 postulated that the energy required for size reduction of a solid would be proportional to the new surface area created during the size reduction. As far as can be determined there is as yet no physical basis for Rittinger&apos;s hypothesis. Rittinger&apos;s hypothesis can be stated mathematically as follows: E, = K(oa-a-0 . [2] Er = energy input per unit volume, K = a constant, <ti = initial specific surface, and o2 = final specific surface. In the size reduction of particles of size x, to particles of another smaller size, x2, Eq. 2 becomes the well known relation: ET = K&apos; {l/x2-l/xx) [3] where K&apos; is a constant. Eq. 3 may be arrived at from the proposition given in Eq. 1 by integrating and by assigning a value of 2 to the exponent n. J dE = J - C dx/x2 E = Kt (1x - 1x) where K&apos; = C. In 1885 Kick3 proposed the theory that equivalent amounts of energy should result in equivalent geometrical changes in the sizes of the pieces of a solid. For example, if one unit of energy reduced a number of equal-sized particles to particles of one half the size, then the same amount of energy applied to the particles resulting from the first test should result again in a size reduction of one half or a final size one quarter the original size. The Kick concept may be expressed as follows: Ek = K" log x1/x2 [41 K" = a constant and E, = energy per unit volume. The expression for Kick&apos;s law may be arrived at by again integrating Eq. 1 and in this case assigning a value of 1 to the exponent n. dE= J - C dx/x Eh = - C In {x/x2) = K" log (x,/x,) where K" = 2.3 C. Application of Kick&apos;s and Rittinger&apos;s laws to comminution has met with varied success. Gross and Zimmerley4 and Piret5 have shown that Rittinger&apos;s equation applies under certain conditions of experimentation. Walker and Shaw6 express the belief that in metal turning and shaping and in grinding of both metals and minerals the production of very fine particles (less than lP) follows Kick&apos;s hypothesis, whereas Rittinger&apos;s concept is valid for the size reduction of coarse particles. For the practical case of crushing and grinding, however, neither of the above hypotheses has received general acceptance. Bond&apos; has lately proposed that since neither Kick&apos;s nor Rittinger&apos;s hypotheses seem correct for plant design work, an energy-size reduction relationship somewhere between the two would be more applicable. The fundamental statement of Bond&apos;s work

Jan 1, 1958

Jan 1, 1949

By R. W. Raymond

THE specimen of anthracite which I exhibit is from the Ortiz Mine Grant, about fifteen miles southwest of Santa Fe. The beds belong to the lignitic formation of the Galisteo, which Hayden and

Jan 1, 1874

By R. W. Raymond

The specimen of anthracite which I exhibit is from the Ortiz Mine Grant, about fifteen miles southwest of Santa Fe. The beds belong to the lignitic formation of the Galisteo, which Hayden and

By G. Carman Ridland

IN conjunction with a geological investigation of the silver-bearing veins at Contact Lake, Northwest Territories, Canada, a survey was made with a Geiger-Müller counter of the gamma-ray emissions from the rocks in the vicinity of the mine workings. Discontinuous pitchblende veins have been encountered occasionally in the silver-bearing fissures, and the geophysical survey was undertaken with the hope that abnormally high gamma-ray intensities, if detected, might lead to larger and more continuous pitchblende discoveries. Before the instrument was used at Contact Lake, preliminary tests were made, first with laboratory specimens at Princeton University, and later over known pitchblende deposits at the Eldorado property, LaBine Point, N.W.T. The Geiger-Müller counter, as adapted for field use, is described; the technique of transporting and operating the instrument is outlined; and the general precautions to be observed are discussed. The results obtained at Great Bear Lake show that the instrument is capable of detecting not only a pitchblende ore shoot in a shear zone, but also the mildly radioactive "host rock" at a considerable distance from the ore body. Hence, use of the Geiger-Müller counter is urged, not just for the detailed search for an ore body in a shear zone, but for the detection of possible radioactive "host rocks" in large-scale reconnaissance surveys of unexplored regions made by prospectors and members of federal geological survey parties.

Jan 1, 1943

By C. Wert, P. Bunn

Determination of the solid solubility of gases in metals is usually done by one of two methods. The first is an additive method, in which measurement is made at temperature of the maximum amount of gas absorbed by an initially degassed piece of the metal. Gas additions are made until the dissolved gas first comes into equilibrium with a compound. This method is most useful at relatively high temperatures where the amount of gas absorbed is relatively large and where equilibration of the dissolved gas with the gas atmosphere can be achieved in a relatively short time. The second is a precipitation method. A supersaturated solution of the gas in the metal is held at temperature until equilibrium is established between the gas atoms in solution and a compound. The quantity of dissolved gas is then determined by some physical measurement which is sensitive only to the gas in solution. This method is generally useful in low temperatures. This paper describes measurement of solubility of nitrogen in tantalum whereby measurements at low temperatures using internal-friction methods are plotted together with existing measurements at high temperatures. The solubility is thereby known from less than 0.5 at. pet at 350°C to near 13 pet at 2300°C. Several measurements have been reported of the solubility of nitrogen in tantalum. These are collected in Fig. 1. Three single determinations by Ke,1 Andrews,2 and Brauer and zapp3 are plotted along with a series of measurements by Vaughn, Stewart and schwartz4 and Gebhardt, Seghezzi, and Fromm.5 Although not much doubt exists about the solubility being in excess of 10 at. pet above 2000°C, the solubility indicated at low temperatures depends on whose data are selected as being most reliable. The variation is enormous, being at least an order of magnitude at 500°C. Accordingly, a measurement was begun to examine this discrepancy. The method of measurement finally selected was that of internal friction. A solid solution of nitrogen in tantalum was prepared by heating a tantalum wire in a dilute at-

Jan 1, 1964

By E. T. Dumble

DuriKg explorations made for the Pacific Improvement Company in the early part of this year, deposits of natural coke, of such extent and excellent quality as to be worthy of record, were found in the Santa Clara coal-field. This coal-field lies in the neighborhood of La Barranca, a small town, 95 miles northeast of Ortiz, on the Sonora railway. The coal-beds are exposed in the drainage-basin of Calera creek, which empties into the Yaqui river opposite Toniche; and the old mining town of Turahumari is nearly at the center of the field. Without going into a detailed geological description, it Will be sufficient to say that the entire area is underlain by rocks of Triassic age, much disturbed in places, and cut through and covered by eruptive rocks of various kinds and ages. The coal-beds occur in a series of interbedded sands and clay, in the upper half of the sedimentary Triassic rocks. Below them is a great series of quartzitic sandstoiles and very sandy slates, and above them are other sandstones, and the eruptive member of the group, viz., the Lista Blanca formation&apos;, described in my paper on the " Geology of Sonora," presented at the New York Meeting of February, 1899.* Speaking very broadly, these sands and clays, with their included coal-beds, dip about 30 degrees S.E. This gives their outcropping edses a 3J.E.-S.W. direction. The general dip

Jan 1, 1900

By R. L. Tobie

Handling and storing ore at transfer points underground are encountered frequently. An ideal solution to these troubles is probably still to be found, but at the Mather mine "B" shaft a method incorporating scraping trenches has been developed giving better service, from the standpoint of safety and simplicity, than obtained from other schemes. When shaft pockets are used for storage, the size of the ground opening required to assure capacity is often prohibitive, and shaft depth below the last level can become excessive, particularly if a crushing station is used. Also, if the material being handled contains large amounts of wet fines, it is difficult, if not impossible, to hold the material with regular chute gates. In order to remedy these problems Cleveland-Cliffs&apos; Mather "B" has utilized three types of trenches. Types I and I1 are now in service and the third is under construction.

Jan 4, 1955