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By P. Martinez, A. F. Hoyte, F. E. Senftle

The possibility of applying a neutron activation technique for silver exploration is considered. A mobile positive-ion accelerator type neutron source is used to irradiate a small area of rock or soil in situ. By using a short period of irradiation and gamma ray spectral analysis, a technique is shown for silver exploration. Two different mobile units are described. Laboratory and preliminary field tests both indicate that a sensitivity of less than 1 oz of silver per ton of ore can be achieved. The increasing consumption of silver for industrial uses and also for coinage has caused a serious shortage of silver in this country. The silver shortage has been reviewed and analyzed by kiilsgaard1 who concludes that, "The best hope for meeting future demands for silver is through accelerated exploration for precious ores." As almost all the exposed "bonanza" type silver deposits evidently have been found, it is urgent that some sensitive geophysical technique be found to detect large, extended, but generally low-grade, secondary ores, as well as hidden vein deposits. Silver is easily made radioactive by exposure to slow neutrons; hence a neutron activation method appears promising for locating silver deposits. The principles of mineral beneficiation using neutron activation techniques were discussed some years ago.2-4 Using the same approach, a preliminary description5 has been published of neutron activation as a mineral exploration tool. An exploration technique is described in which silver is made radioactive in situ and detected with a gamma radiation counter. The technique is similar to the well-known method used for uranium exploration. THEORETICAL CONSIDERATIONS Elemental silver consists of two isotopes, Ag107 and Ag109, having naturally occurring isotopic abundances of 51.4% and 48.6%, respectively. For short periods of irradiation of silver by thermal neutrons, the long-lived 250 day, half-life isotope, Ag110m, is not produced in significant quantities. However, significant quantities of 2.3 min half-life Ag108 and 24.5 sec half-life Agl10 are formed by the following reactions. Ag108 and Agl10 emit a 0.44 Mev (million electron volts) and a 0.66 Mev gamma ray, respectively. Ag107 + n + Ag108 (2.3 min) Ag109 + n + Ag110 (24.5 sec). Because of the large capture cross section (110 barns) of Ag109, and short half-life of Ag110 (24.5 sec), the 0.66-Mev gamma ray is the most prominent emission from silver for neutron activation periods of about a minute's duration.* The 0.44-Mev gamma ray from Ag108 will also be present, but will be one or two orders of magnitude lower in intensity. The decay scheme of Ag110 is shown in Fig. 1. If the neutron irradiation time is limited to about 100 sec, the Ag110 activity will essentially reach saturation and can be used to detect the presence of silver. In a neutron flux of 10 8 neutrons/cm2/set, the induced 0.66-Mev activity in 1 g of silver will be about 2 x 107 disintegrations per sec. This is about 1000 times the measurable gamma activity of 1 g of uranium in equilibrium with all its decay products; hence there is ample activity for detection. Under the same conditions of activation, most of the other elements do not reach this relatively high disintegration rate. Although this is in favor of the proposed technique, other problems must be considered. For mobile operation, it is desirable to obtain the largest neutron flux to weight ratio. Hence we have used a small 150-kev accelerator-type neutron source rather than an isotopic source such as an americium-beryllium neutron source. By use of remote control system, an accelerator-type neutron source can be safely used without the massive shield required for an isotopic source. Moreover, an accelerator-type source is more versatile in that it allows one to use a flux of either 14-Mev or 3-Mev neutrons, depending on whether a tritium or a deuterium target is used. With a 14-Mev generator, one can obtain a flux of 10 9 neutrons/cm 2/sec, and with a 3-Mev generator, the flux is generally two orders of magnitude less. Although silver will become activated with either generator using proper moderation, detection may be

Jan 1, 1968

By John D. Wiebmer

Kansas, with its thin seams and tough overburden, may not be anyone's first choice for a coal mining operation. But there are operators making it pay through careful attention to mining techniques and aggressive marketing in the local region. One of the few Kansas coal operators is Bill Patch, who has been in the business for 28 years. Beginning with a single dragline operation near his home in Welch, Okla., Bill's Coal Co. weathered some lean times during the "soft" coal market of the 1950's and 1960's. But his tenacity paid off when new markets began opening up, and the company has grown by leaps and bounds in recent years. In 1975, the Fort Scott mine opened in Bourbon County, Kansas; in 1976, the Porter mine began production in Wagoner County, Okla.; in 1977, the Fulton mine opened near Fulton, Kansas. In addition, the original Welch mine in Oklahoma is still a producer, and this year the company will open a new mine at Chetopa, Kansas.

Jan 9, 1978

By Walter Kauenhowen

The crude-oil production of Germany without Austria during 1938 amounted to 3,864,518 bbl., representing an increase of 21.7 per cent over the 3,173,373 bbl. produced in 1937. Adding the Austrian production, the crude-oil production of the new German Reich totaled 4,259,717 bbl. during 1938, representing an increase of 25.3 per cent compared with the respective figures of the previous year. According to published official data, and using a conversion factor of 1 metric ton equaling 7 bbl., the oil production of Germany in 1938 was as shown in Table 1. A semiofficial publication1 states that the program of the crude-oil industry for the second year (1938) of the four-year plan was successfully accomplished. According to the same source, new drilling developments at the following localities were promising: Reitbrook near Hamburg, Heide in Holstein, Eicklingen-Sandlingen near Celle, Steimbke near Nienburg, Worms in the Rhine Valley, Gifhorn near Braunschweig, Mölme near Oberg, and at other places. The drilling activity for oil is illustrated by the figures in Table 2.

Jan 1, 1939

By Walter Kauenhowen

The crude-oil production of Germany without Austria during 1938 amounted to 3,864,518 bbl., representing an increase of 21.7 per cent over the 3,173,373 bbl. produced in 1937. Adding the Austrian production, the crude-oil production of the new German Reich totaled 4,259,717 bbl. during 1938, representing an increase of 25.3 per cent compared with the respective figures of the previous year. According to published official data, and using a conversion factor of 1 metric ton equaling 7 bbl., the oil production of Germany in 1938 was as shown in Table 1. A semiofficial publication1 states that the program of the crude-oil industry for the second year (1938) of the four-year plan was successfully accomplished. According to the same source, new drilling developments at the following localities were promising: Reitbrook near Hamburg, Heide in Holstein, Eicklingen-Sandlingen near Celle, Steimbke near Nienburg, Worms in the Rhine Valley, Gifhorn near Braunschweig, Mölme near Oberg, and at other places. The drilling activity for oil is illustrated by the figures in Table 2.

Jan 1, 1939

By E. Morgan Massey

Located in virgin coal acreage near Gilbert, W. Va., Massey Coal Mining Co.'s Ben Creek No. 2 mine afforded the company's engineers the opportunity of designing and laying out the entire mining operation from the mine faces to the railroading loading site. However, the topography of this region posed difficult problems in haulage of coal for, in this extremely rugged terrain the uppermost coal seams lay in the mountain-top ridges, approximately 1400 ft above the valley floor. The decision for mining equipment naturally leaned to the new high-capacity continuous miners where seam conditions permitted: otherwise, to the new super-high capacity conventional cutting and loading machines. Since the coal seams lay in ridges and points of considerable outcropping, the decision was to keep the transportation on the surface and mine the coal with multiple entries into the outcrop. This way, the major problems of underground haulage, drainage, and ventilation are eliminated, and the opportunity to take advantage of a-c underground power becomes a much simpler proposition.

Jan 10, 1960

By Frank M. Stephens, Robert D. Macdonald

As processes for handling low-grade or complex ores become more complicated and as new methods are found, the need arises for more complete and detailed pilot-plant studies to protect the capital investment required for a full-scale plant. Occasionally a process is firm technically, but there is a need for a demonstration plant that will convince nontechnical men of the wisdom of investing in a full-scale operation.

Jan 5, 1959

By Reino Kurppa

The Pyhäsalmi mine of the Outokumpu Co. is located in central Finland (Fig. 1). The deposit was discovered in the autumn of 1958. Construction of the mine was started a year later, and production began on Mar. 1, 1962 (Fig. 2). At present, 750,000 metric tons (mt) of ore and a nearly equal amount of country rock are mined annually. Slightly over one-half million tons of various concentrates are produced per year, of which 85% is pyrite concentrate, 10% zinc concentrate, and 5% copper concentrate. The pyrite concentrate is treated in the company's pyrite smelter,1 yielding elementary sulfur, sulfur dioxide, and iron-oxide cinders, as well as electric power. Thus all the sulfides, totaling 75% of the ore, are of economic value. This is a fact which had a bearing on the development of the stoping method. GEOLOGY The ore is of breccia type containing fragments of country rock of varying sizes. It is coarse-grained pyrite ore containing sphalerite and chalcopyrite as a matrix between the pyrite grains. Only small amounts of pyrrhotite have been observed in certain marginal parts of the orebody. The ore averages 0.85% Cu, 3.0% Zn, 38% S, and 33% Fe. The orebody extends from the surface down to at least 500 m, which is the lowest level from which present information has been obtained. Horizontally, the orebody is 650 m long. It is 75 m wide at its central part, narrowing towards the ends (Fig. 3). At a depth of 115 m, the orebody suddenly narrows down to a thickness of 25 to 30 m. In the northern part of the orebody, the dip is 50° to 70°, but elsewhere it is almost vertical (Fig. 3).

Jan 1, 1969

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

Based on pole figure data and microstructural observations, the re-crystallization orientation found in a copper strip previously cold-rolled 99.5 pct from a single crystal with an initial (110) [112] orientation may be described as: a 30° rotation, clockwise and counterclockwise, about octahedral poles of the cold-rolled texture such that all four poles function at a low annealing temperature (400°C) and only three of them function at high temperatures (500' to 1050°C). The relative intensity of deformation stresses on various slip planes can be correlated with the choice of poles affecting the rotations found in the recrystallized orientations. ROTATIONAL reorientation about the poles of densely packed crystallographic planes is an important characteristic of secondary recrystallization" in face-centered cubic metals. Some evidence has also been interpreted to show that such a rotational relationship also exists in the primary recrys-tallization process." In an investigation of the crystallographic relationships in the recrystallization process, several aspects of the experimental procedure should be considered. With cold-rolled poly-crystalline metal as the initial material, pole figure analysis leaves many ambiguities as to whether or not simple indices can be assigned to adequately represent its orientation. The rolling texture does not consist of a single texture. Minor deformation textures are usually present. In all cases, twin textures are present. The presence of both minor and twin deformation textures influences the recrystallization texture. In order to study the recrystallization mechanism, a more precise knowledge of the history of the material before recrystallization is necessary. Tensile deformation of a single crystal usually produces residual stresses which are concentrated at slip bands. Since the exact nature and orientation of these potential nuclei sites cannot be experimentally evaluated, the tensile deformation of a single crystal was not considered adequate. From the work done by Barrett and Steadman6 n copper, it appeared that cold rolling of a single-crystal specimen with an initial (110) [112] orientation would yield a specimen which fulfills the conditions required for the present investigation, namely a highly preferred single rolling texture with relatively homogeneous stress distribution. By investigating the recrystallization texture of this material, additional details of reorientation during recrystallization might be obtained. The purpose of this paper is to describe such an investigation. Experimental Procedure Copper used in the present investigation was cathode sheet with a purity of 99.94 to 99.97 pct. A copper single-crystal specimen, 1.15x0.8720x0.5322 in. (thickness) was cut from a cylindrical crystal which was grown in a Bridgman furnace.' The cutting was accomplished on a horizontal milling machine operated at a very slow speed to obtain a (110) plane in the rolling plane and a [112] direction in the rolling direction. The disturbed surface was removed by electrolytic polishing in dilute orthophos-phoric acid (H3PO4) with a specific gravity of 1.14, and a current density of about 1 to 2 amp per sq cm. A 3-min polishing was needed to eliminate the disturbed surface causing Debye-Scherrer rings and a 45-min polish produced a surface which yielded sharp rounded Laue spots. It was estimated that about 1/16 in. of metal was removed from the original cut surface. The final orientation of this specimen before rolling was about 2" from the (110) plane in the rolling plane with a [112] direction aligned in the rolling direction. It is possible that a small amount of strain was still present in the cube despite the fact that the Laue spots seemed very sharp. It is doubtful, however, that this would be an important factor after a subsequent rolling reduction of 99.5 pct. This copper specimen was rolled on a laboratory rolling mill with two highly polished rolls 37/8 in. in diam in the following manner: 0.010 in. per pass to 50 pct reduction, 0.005 in. to 70 pct, 0.002 in. to 85 pct and, finally, 0.001 in. per pass to a 99.5 pct reduction. Specimens, about 1 in. sq with the rolling edges intact, were cut from the rolled strip by the electrolytic method previously described, after the strip

Jan 1, 1954

By Ralph E. Esarey, G. F. Fix

The oil and gas industry in Indiana in 1938 showed considerable improvement over the preceding year. Most of the drilling and development during the year, as in the past several years, was in the Indiana portion of the Illinois Basin, but increasing interest was apparent in the old Trenton area, for possibilities of further production in the Trenton formation and the underlying St. Peter sandstone. Interest in all other portions of the state was at a new peak, since many areas have never been prospected. Natural gas production continued to drop during 1938, since new discoveries have not been able to keep pace with the rapid decline in older areas. Oil production increased considerably, chiefly through the discovery of new fields. Older fields contributed about the same quantity of oil during 1938 as during the preceding year. There were 159 wells completed in Indiana during 1938, an increase of 25 over the preceding year. Of these, 48 were oil wells, 41 were gas, and '70 failed to find commercial production. Forty-three, or about 20 per cent, were wildcat. Six of these were productive—three oil wells and three gas wells. Thirty-nine wells on which operations started during the year had riot been completed by Dec. 31. Fourteen others were temporarily abandoned, with the possibility that several will be drilled to completion in the near future. A new oil field (Heusler) was discovered in May 1938, in sees. 1 and 12, T. 7 S., R. 12 W., Posey County. Production was found in the Waltersburg (Upper (Chester) sandstone at a depth of approximately 1775 ft. At the close of the year, Heusler field had nine producing wells and two drilling. The Point township area, Posey County, near the confluence of the Wabash and Ohio Rivers, held promise of good production from the McClosky lime, but offsets to the, discovery well had only shows of oil. The discovery well declined rapidly in production arid was finally plugged. In the Oaktown field, Knox County, a wildcat came in with a good flow of gas, extending the field to the east, and proving considerably more acreage. A new gas area was discovered in Sullivan County, and four good wells were completed. The discovery well was in sec. 35, T. 8 N., R. 10 W., and had an initial

Jan 1, 1939

By Ralph E. Esarey, G. F. Fix

The oil and gas industry in Indiana in 1938 showed considerable improvement over the preceding year. Most of the drilling and development during the year, as in the past several years, was in the Indiana portion of the Illinois Basin, but increasing interest was apparent in the old Trenton area, for possibilities of further production in the Trenton formation and the underlying St. Peter sandstone. Interest in all other portions of the state was at a new peak, since many areas have never been prospected. Natural gas production continued to drop during 1938, since new discoveries have not been able to keep pace with the rapid decline in older areas. Oil production increased considerably, chiefly through the discovery of new fields. Older fields contributed about the same quantity of oil during 1938 as during the preceding year. There were 159 wells completed in Indiana during 1938, an increase of 25 over the preceding year. Of these, 48 were oil wells, 41 were gas, and '70 failed to find commercial production. Forty-three, or about 20 per cent, were wildcat. Six of these were productive—three oil wells and three gas wells. Thirty-nine wells on which operations started during the year had riot been completed by Dec. 31. Fourteen others were temporarily abandoned, with the possibility that several will be drilled to completion in the near future. A new oil field (Heusler) was discovered in May 1938, in sees. 1 and 12, T. 7 S., R. 12 W., Posey County. Production was found in the Waltersburg (Upper (Chester) sandstone at a depth of approximately 1775 ft. At the close of the year, Heusler field had nine producing wells and two drilling. The Point township area, Posey County, near the confluence of the Wabash and Ohio Rivers, held promise of good production from the McClosky lime, but offsets to the, discovery well had only shows of oil. The discovery well declined rapidly in production arid was finally plugged. In the Oaktown field, Knox County, a wildcat came in with a good flow of gas, extending the field to the east, and proving considerably more acreage. A new gas area was discovered in Sullivan County, and four good wells were completed. The discovery well was in sec. 35, T. 8 N., R. 10 W., and had an initial

Jan 1, 1939

By John C. F. Randolph

(Read at the Amenia Meeting, October, 1877.) Tits establishment being now in full working order, it has seemed of considerable professional interest to collect together, in a concise form, the various points as to its plan, method of dressing, and equipment. The data contained in this paper have been largely drawn from the able paper of E. Kutscher, constructing engineer. of the works, contained in the Zeitschrift fur Berg-Hütten-und Salinenuesen im Preussischen Staate, 1873, supplemented by some personal memoranda made while the works were under construction and by memoranda on the works appearing in various German technical papers from their completion up to date. This is probably the largest dressing works in the world devoted to the beneficiation of argentiferous lead ores, and it is doubtful if any establishment for the concentration of mineral of any description can compare with it in size. As showing the final practice adopted in an old and very conservative mining region, in which the concentration of ores has been a matter of constant practice and experiment for a very long period, these works are of peculiar interest. The fact that the Clausthal ores strongly resemble a very large and abundant class of ores found in the United States has always attracted the attention of American mining engineers and mine owners to the methods employed in dressing and smelting them. The study of their methods of concentration of ores has, however, always been full of difficulty,

Jan 1, 1878

By John H. Bassarear, Harold W. Sorstokke

The fourth expansion within 10 years was completed at Pima Mining Co. during late 1971. The first three expansions increased capacity from 3000 to over 40,000 tpd. Conventional crushing and grinding practices were used in the original 10-section mill. Total capacity is now approximately 54,000 tpd. Expansion IV includes a new primary crusher and a radial stacker conveyor that feeds stockpiles for both concentrators. The -8-in. primary product is fed from the reclaim stockpile to the new mill by two pairs of pan feeders, each pair feeding a separate conveyor. The reclaim conveyors each feed 28 X 12-ft semiautogenous mills operating with an 8% charge of 4-in. balls. Autogenous discharge is screened, oversize recycling by conveyors, with -%-in. undersize feeding two conventional 161/2 X 19-ft ball mills in closed circuit with cyclones. Cyclone overflow is pumped to three parallel rows of 300-400 cu ft flotation cells. Rougher and scavenger concentrates produced are sent to the original mill for regrind, cleaning, and filtering.

Jan 1, 1974

By S. N. Sharma, William Davis

Because of diminishing energy resources and rising energy costs, every industry is forced to carefully examine its pattern of energy consumption. The copper industry is no exception; current smelting practice begs for technological innovations that would improve the efficiency of its energy utilization. The thermochemical simplicity of copper metal production, as shown in Fig. 1, is deceptive. Designed from the same basic principles, there are four major commercial processes either in use or under construction; and others, such as the Mitsubishi process, are being developed.

Jan 5, 1977

By K. L. Young

The general energy equation, including change in kinetic energy, was solved by numerical integration and used to evaluate simplifying assumptions and application practices over a wide range of conditions. When extreme conditions were encountered, sizable errors were caused by large integration intervals, application of Simpson's rule and neglecting change in kinetic energy. A maximum error of only 1.31 percent was caused by assuming temperature and compressibility constants at their average value. It was discovered that a discontinuity can develop in the integral for the injection case. This discontinuity indicates a point of zero pressure change and is an inflection point in the pressure traverse. INTRODUCTION When a pressure in a gas well is to be calculated, one of the first decisions is to select a method of calculation. In many instances, this selection becomes a problem because the literature, at best, provides an evaluation of any method for only a limited range of conditions. Once a method has been selected, a question often arises as to the size of the calculation interval which should be used. The question regarding calculation interval arises because an analytic solution is not obtainable and approximate solutions must be used. This paper presents an evaluation of major assumptions and application practices of probably the two most widely used methods for calculating steady-state single-phase gas well pressures. The two methods are Cullender and Smith1-" (numerical integration), and average temperature and com-pressibility. The Cullender-Smith method assumes that change in kinetic energy is negligible and is normally applied in two steps with a Simpson's rule correcton. The average temperature and compressibility method, in addition to neglecting kinetic energy change, asumes that temperature and compressibility are constant at their average values. This method is normally applied for wellhead shut-in pressures of less than 2,000 psi, and in one step. Computer programs were written to compute bottom-hole pressure with and without the assumptions, using various approaches. Values of input parameters investigated are shown in Table 1. Flow rate was limited to a maximum of 5,000 and 10,000 Mcf/D for tubing sizes of 1.610 and 1.995 in. ID, respectively. Flow rate was also limited to 10,000 Mcf/D for a tubing size of 2.441 in. ID when wellhead flowing pressure was 100 psia. These limitations were imposed on flow rate so as not to exceed sonic velocity. The z factor routine available necessitated limiting bottom-hole temperature to 240F and wellhead pressure to 3,000 psia. Pressures were compared on the basis of percent deviation from the trapezoidal integration of Eq. l or 2 at 100-ft intervals. A preliminary investigation indicated that a 1,000-ft interval solution would differ from a 50-ft interval solution by less than 0.25 percent; therefore, the 100-ft interval was chosen for a base. For the purpose of comparison, deviations less than 1 percent were considered insignificant. where 111.1 qeC2/d p = kinetic energy term. Eqs. 1 and 2 can be evaluated numerically at specific depths using the trapezoidal rule as shown by Cullender and Smith. If change in kinetic energy is neglected and temperature and compressibility are assumed constant at their average values, Eq. 1 can be integrated to give the average temperature and compressibility equation,

Joseph E. Thropp, Jr., Indiana Harbor, Ind.:—To what do you attribute the fact that in some localities the by-product coke sells at a premium over the ordinary bee-hive coke for foundry use ? If the cell-structure is preferably soft and rather thick in coke for foundry use, as I understand it, do you mean that by-product coke has soft and thick cell-walls ? William H. Blauvelt, Syracuse, N. Y.:—As I say in one of the paragraphs of my paper, the tendency seems to be towards the manufacture of foundry- and furnace-coke under somewhat different conditions. The development of the best cell-structure in coke, of course, has not reached perfection, but we are making progress, and we are inclined to believe that under ordinary conditions the best furnace-coke, that is, coke with the hard cell-wall and the well-developed cell, is produced at fast coking-time and high heats, whereas the best foundry-coke seems to be produced at somewhat lower heats. In one of our plants we are making furnace-coke in 16-hr. coking-time, and foundry-coke in 20-hr. time. Foundry-men want the strong, tough coke. I think the furnace-men present will agree that the best furnace-practice requires a hard coke, with a well-developed cell-structure. Replying to the question as to the reason for higher prices being realized for by-product foundry-coke than for bee-hive coke, of course, the immediate reason is that it suits the foundry-men better. Perhaps one cause may be that we are able, by the selection of coals, which is not usually practicable at bee-hive plants, to get a quality and analysis best suited to foundry-work, with high carbon-content, and with cell-structure and physical strength especially suited to the foundry-men's ideas.

Jan 1, 1913

By F. W. Maclennan

PAPERS by D. B. Scott, E. G. Deane, and J. H. Hensley, Jr.1 describe the succession of mining methods used in the Miami mine—squarelset system, shrinkage stoping, top-slicing method, and the undercut caving system which was then being used, and which embraced the use of finger raises. The last-named system worked well but when the rich ore was exhausted it became necessary to reduce costs so as to make available a low-grade ore containing an average of less than 0.9 per cent. total copper with less than 0.8 per cent. in sulfide form and with no precious-metal values. There was then developed for this low-grade ore the system of separate large block-caving stopes, in lateral dimensions 150 by 300 ft., or 150 by 150 ft., with intervals between stopes of the same size so that subsequently these pillars may be similarly mined. The results have been most favorable. Under the previous system the production of ore per man-shift for all underground labor was 8 tons. The present production per man-shift underground is 28 tons. In starting this work the problems were: 1. How the ground would cave above the stopes. 2. Whether in the first stopes caving would encroach on the pillars as laid out. 3. Whether in subsequent mining of the pillars waste filling would be drawn from the previously caved adjacent stopes. Fig. 1 is a small key plan for showing the location of cross-sections as well as of ore mined and the limit of the escarpment and limit of cracking on the surface caused by the caving of the capping overlying the ore

Jan 1, 1929

By Hsun Hu

NOT much data are available in the literature on textures in cross-rolled metal sheets. Among the body-centered-cubic metals, a few investigators have studied the preferred orientations developed in cross-rolled and in subsequently annealed molybdenum specimens.1-4 Semchyshen and Timmons5 onstructed complete pole figures for the cross-rolled and subsequently annealed arc-cast molybdenum. They used the conventional photographic method. Similar data on cross-rolled iron are still lacking. In view of the fundamental importance of iron as a basic metal for magnetic alloys and many industrial steels, the present investigation was undertaken in an attempt to understand more about its properties. The material selected for the present work was of high purity, and the textures were determined by the Geiger counter spectrometer technique, which permits the construction of quantitative pole figures. Experimental Procedure The material used for this investigation was NRC (National Research Corp.) high-purity, gas-free iron. The total gas content (N2 + O2 + H2) given was less than 0.026 pct, and the carbon content, less than 0.005 pct. Spectrographic analysis of a 2 in. cast ingot showed the percentage of metallic impurities as 0.0004 pct Cu, 0.0002 pct Mg, 0.001 pct Mn, 0.01 pct Ni, and 0.006 pct Si. A 1 in. thick slice was cut off from the 2 in. cast ingot. It was hot-forged at 850 °C to destroy most of the cast structure. Surface scale was removed by milling the forged piece to a size 2 in. long, 1½ in. wide, and ¾ in. thick. After normalizing at 915 °C for 15 min, the piece was alternately cold-rolled 40 pct and annealed at 750°C in hydrogen to a final thickness of 0.165 in., with a resulting uniform grain size of 0.1 mm.

Jan 1, 1958

By W. C. PAGE

HARVEY S. MUDD has the unusual distinction of having virtually inherited a Directorship in the -A.I.M.E., for he was appointed to the Board to fill the unexpired term of his father in 1926. Since then he has served as a Director continuously until 1936, and now he is a candidate for Vice-President. One of the first words that young Harvey tried to say was "ore," for he was born in Leadville, Colorado, in the heyday of that camp, where Seeley W. Mudd for years ran the Small Hopes mine. Stanford and Columbia gave him his mining education, and the Shattuck-Arizona, at Bisbee, his first job. Afterwards he examined many

Jan 1, 1937

By M. F. COOLBAUGH

WHEN I was asked to speak on the subject of leaching, I did not realize that a complete summary of recent progress in leaching had been given by Stuart Croasdale. I shall try to give some other phases of the subject that were not touched by Mr. Croasdale. Not all metallurgists are in harmony as to their methods of treating metals. If they were it would probably mean lack of progress. They can be divided into two classes-the pyrometallurgists, using fire means, and the hydrometallurgists, or those using leaching methods. Conflict is always good for progress; we have it in politics, and in religion there are fundamentalists, and those who are not fundamentalists. As representing pyrometallurgy, may I hope not to be classed among the fundamentalists. The leaching of ores is not new. The leaching of ores for the recovery of metals, however, is quite new. The older leaching was simply to recover the salts. Agricola, back in 1555, I think it was, outlined a great many methods of leaching for the recovery of salts. They called them solid juices at that time. There was no real competition, however, between leaching meth-

Jan 1, 1926

By C. E. Beecher

THE application of gas or air under pressure to obtain more oil from a sand which has been practically exhausted by ordinary production methods has been practiced to a limited extent for many years. Until recently such methods were confined to the Eastern fields, principally those of Ohio and West Virginia, where in many cases the production obtained after applying pressure for a few years was nearly equal to the total production prior to that time which had been obtained by the usual production methods.' As early as 1917, J. 0. Lewis1 called attention to this method of increasing the recovery of oil and cited the phenomenal results obtained by H. E. Smith, I. L. Dunn and 0. C. Dunn, who pioneered the application of air or gas pressure recovery methods. With this information available it would appear that other oil-producing sections of the country have been extremely slow to realize the advantages of repressuring. However, after a few successful projects in the Mid-Continent area, the oil producers appreciated the value of this method for obtaining further and profitable production from their practically exhausted leases and are now making extensive use of it. In general, it has been the practice to apply pressure to the sands when production has declined to a small yield per well. The purpose of this paper is to discuss some of the advantages which may be expected from returning gas under pressure to the oil sands during the early stages of development, before the rock pressure has been dissipated and the gas exhausted, and to stimulate discussion of this subject on which comparatively little actual field data are available.

Jan 1, 1928