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By Douglass D. Donald

The New Jersey Zinc Co. successfully holed through a 2 ½ -mile haulage tunnel connecting its new Ivanhoe shaft with the Van Mater Shaft at Austinville, Va. This 8 x 10-ft cross-section tunnel was driven from both ends and met at a point approximately a mile from one shaft and a mile and a half from the other. In order to make certain that the faces met accurately on line and grade it was necessary to refine conventional mine surveying practices. The mines that are serviced by these shafts are located in the southwestern part of Virginia approximately midway between Roanoke and Bristol at the west foot of the Blue Ridge. While the presence of lead-zinc sulfide ores has been known in this area for more than 200 years, it was in 1902 that New Jersey Zinc Co. acquired the Austinville property, which has been in constant operation since that time. About ten years ago the company undertook an extensive diamond drilling program at Ivanhoe several miles to the southwest. This program was successful in locating sufficient ore to justify the purchase of a number of the properties in this area and plans were made to develop the new orebodies. The discovery of this ore as well as substantial additional reserves at Austinville resulted in a decision by the company to increase its daily milling capacity to 3000 tons, of which about 1000 tons would be supplied from the Ivanhoe mine.

Jan 9, 1958

By Paul L. Goddard, Alfred G. Hoyl, William R. Sirola

A good place to look for elephants is in elephant country, and old mining districts are certainly elephant country as far as minerals are concerned. In many areas probably more ore is still in the ground than has been taken out. The old timers were good miners and hard workers and when they left ore behind, it was usually for good reason; but many an old mining district has been revived by new approaches to old problems, taking advantage of new techniques and new equipment. One of these is the Front Range mineral belt of Colorado, which has produced minerals for the past 100 years through the ups and downs of mineral prices and the general economy. Gold, silver, copper, lead, and zinc have been found in abundance in the complex sulfide veins of the area. Between Idaho Springs and Central City lie several strong veins which have been mined successfully in the past. The two strongest of these veins, striking northeast-southwest, (Lake-Bald Eagle), and northwest-southeast, (Crown Point-Belman) , and dipping northeast and northwest, respectively, intersect in a flat X near the head of Virginia Canyon. From the lowest drainage of the area, Clear Creek Canyon, the old timers drove the Central, or Big Five, haulage-drainage tunnel due north. It intersects the two veins 8460 ft from the portal and 1670 ft below the surface. The two veins were mined successfully at the surface and at the tunnel level. Without an opening to the surface at the in- side end of the tunnel, ventilating became very difficult as the stopes were opened up, and mining ceased in 1929. Vertically, 1200 to 1600 ft of virgin ground remains in the veins.

Jan 6, 1959

By E. F. Koch, J. L. Walter

oriented crystals of iron and iron with 3, 5, and 6.25 pct Si were rolled to reductions of 10 and 70 to 97 pct at room temperature. Similarly oriented crystals were deformed in tension. Dislocation substructures of the deformed crystals were observed by transmission electron microscopy to determine the effect of silicon on the formation of substructures. Pole figures were obtained to relate orientation changes to substructure. When rolled 10 pct, the iron crystals and the 3 pct Si-Fe crystals formed cells, 1 and 0.2 u in diameter, respecliuely. Cells were absent in the higher-silicon crystals. Extended dislocations and possible stacking faults were observed in the 6.25 pct Si-Fe crystal rolled 10 pct and annealed at 650°C. The stacking-fault energy was estimated to be 20 ergs per sq cm. Rolling to 70 pct resulted in the formation of sub-bands (0.9 µ wide) ill the iron crystals and transition bands (containing 0.2-µ-wide subbands) in the 3 pct Si crystals. No subbands formed in the 5 pct Si-Fe crystal until it was ankzealed. SliP occurred on (112) planes ill tension. The slip traces on the 3 pct Si crystal were wary while those on the 5 pct Si crystal wvere straight. The strain-hardening coefficient for the 5 pct Si crystal was nearly zero. Cells did not form, at least at elongations up to 10 pet. The results suggest that cross slip of iron is restricted by additions of silicon beyond about 3 pct possibly by formation of immobile extended dislocations. IN a previous paper' the authors described the substructures developed in (100)[001]-oriented crystals of 3 pct Si-Fe which were rolled to reductions of 10 to 90 pct at room temperature. At low reductions (10 to 20 pct) cells, approximately 0.2 to 0.3 ja in diameter, were formed. The cell walls consisted mainly of edge dislocations. With increasing reduction (up to 50 pct) the cells were seen to elongate in the rolling direction. In certain regions of the crystal there were significant reorientations which were characterized as rotations about an axis normal to the (100) or rolling plane. These regions were called "transition bands". The regions in which there were no reorientations were called ('deformation bands". At reductions of 60 to 70 pct the elongated cells in the transition bands became sub-bands separated by low-angle tilt boundaries with angles of disorientation of about 2 deg. The elongated cell structure in the deformation band was replaced by a general distribution of dislocations. It was noted that the width of the subbands in the transition bands remained 0.2 to 0.3 µ; i .e., the width of the subbands was the same as the initial cell diameter for reductions up to at least 70 pct. From this, and from considerations of the mechanism of formation of the transition bands,' it was concluded that the subbands evolved directly from the initial cells. In order to check this conclusion, it was decided to examine the relationship between initial cell diameter and width of subbands produced by large rolling reductions. Cell size is known to be dependent upon the temperature of deformation.2,3 However, preliminary experiments with 3 pct Si-Fe crystals indicated that the change in cell size with increasing temperature of deform,ation was not sufficient for the present purpose. On the other hand, cell diameters generally reported for iron deformed at room temperature2'3 range from 1 to 2 p, a factor of 3 to 10 larger than the cells in 3 pct Si-Fe rolled to 10 pct reduction,' indicating the possibility of a marked dependence of substructure (at least in terms of cell size) on the amount of silicon in iron. Thus, the investigation was enlarged to include the study of the effects of varying silicon content on substructure in lightly rolled as well as in heavily rolled crystals of iron and iron with 3, 5, and 6.25 pct Si. The crystals used in this study all had the same orientation, (100)[001], with respect to rolling plane and rolling direction. These were rolled to reductions of from 10 to 97 pct and the substructures determined by electron transmission microscopy in both the rolled state and after annealing. In addition, stress-strain curves were obtained from (100)[001]-oriented crystals of iron and 3 and 5 pct Si-Fe to determine the effect of silicon on tensile properties. The dislocation substructure of the tensile specimens was also determined for Samples pulled to 2 and 10 pct elongation at room temperature for comparison with the substructures produced by rolling. 1) EXPERIMENTAL PROCEDURE Crystals with 3, 5, and 6.25 pct Si were prepared by annealing 0.012-in.-thick sheets of high-purity Si-Fe in purified argon at 1200°C to effect growth

Jan 1, 1965

By J. E. Lawver, J. D. Raulerson, J. P. Bernardi, R. S. Hearon, D. Lynch, G. F. McKereghan

Despite recent economic problems, the future of the Florida phosphate industry appears optimistic. Florida has enormous reserves and will continue to produce a third of the world's phosphate supply simply by making changes in the present system of mining, beneficiation, waste disposal, and land reclamation. The geology and mineralogy of future deposits are discussed with reference to specific deposits. Lower ore grades, increasing power costs, and environmental regulations are necessitating development of new concepts of mining and matrix transportation. Because one of the ores to be mined in the future contains appreciable amounts of dolomite, research and development efforts are being concentrated on new techniques in beneficiation. Changes are being made in plant design to meet environmental and regulation standards. However, the expected new technology outlined for the industry depends on the geology and mineralogy of future reserves.

Jan 1, 1985

By Victor deWolfe

INTRODUCTION The Henderson Mine, located near Empire, Colorado, utilizes a continuous panel caving system to extract ore as one of the world's major producers of molybdenum. Any mine using a caving-by-gravity technique of mining must rely on closely controlled draw of the caved ore. This control is essential to insure proper caving action, to avoid damaging load concentrations of weight and to minimize the dilution of ore with waste material. Henderson is no exception. Draw control is a major factor in all production planning, from long- range plans to short-range and day-to-day ore scheduling. Draw control is reviewed constantly and administered daily in an effort to optimize production efficiency, ore recovery, and cave management. MINING METHOD The cave at Henderson is massive, moving slowly through large panels that are 244 m (800 ft.) wide by 610 m (2,000 ft.) long. Generally two cave areas are drawn at one time. The areas under active draw vary in size but can be as large as 244 m (800 ft.) by 244 m (800 ft. ) containing 400 draw points. Each draw point contains 45,360 mt (50,000 st) on the average and takes about two and one half years to exhaust. A complete panel is worked for seven to ten years. No pillar exists between panels, but rather a buffer zone of broken ore, or "static face," is left in each panel to be drawn with the adjacent, yet-to-be-caved panel in efforts of minimizing dilution of a working area from an exhausted one. (Figure 1) Production drifts are driven on 24.4 m (80 ft.) centers through the ore body. Between the production drifts are funnel-shaped draw bells on 12.2 m (40 ft.) x 24.4 m (80 ft.) centers to receive ore from the cave. Each bell is accessed by two draw points, one from the production drift on either side, thus forming a 12.2 m (40 ft.) x 12.2 m (40 ft.) draw pattern. Extraction of the ore is by rubber-tired, 3.8 m3 (5 yd3) load-haul-dump equipment. The LHDs then tram the ore a maximum of 49 m (160 ft.) to ore passes. Cave initiation and bell development are done from the undercut drifts which are parallel to and 17 m (55 ft.) directly above the production drifts. Longhole rings are drilled and blasted from the undercut drifts to define the bells and establish the undercut for caving. (Figure 2) DRAW CONTROL Since the cave line at Henderson is constantly advancing, it is necessary to be continually initiating new cave at one end while exhausting it at the opposite end. There must exist, therefore, an angle on the ore-waste contact in the broken rock from initiation to exhaustion. The basic concept of draw control is to keep this angle as smooth and even as possible, particularly at the time of exhaustion. If this is achieved, draw points are exhausted more or less in a line, avoiding pockets of remaining ore surrounded by exhausted areas. These pockets would cause spotty ore extraction at the time of exhaustion, increasing the amount of dilution occurring while introducing the potential for significant weight problems in the production area. To arrive at the desired angle on the ore- waste contact, maximum tonnage percentages are assigned to each row of draw points increasing at 10% or 15% increments (depending on cave size and velocity of draw) working away from the cave line. The available tonnage indicated by these percentages is the maximum allowable tonnage to be extracted from each draw point until the available tonnage percent- age is increased. As the cave moves, these percentages increase for each draw point regularly. However, in general the tonnage drawn from each draw point is kept at about 50% of this allowable maximum in order to maintain adequate available tonnage in the cave to sustain production for seven months if cave initiation were to cease. This available tonnage cushion is a safeguard built into the draw control program at Henderson to accommodate fluctuations in the rate of cave advance. When draw points move past the row of 100% tonnage availability, they are drawn past the desired 50% at the same increments per row until exhausted. (Figure 3) To achieve proper draw control, the number of LHD buckets to be taken from each draw point is assigned daily. The actual buckets taken, which may at times deviate from the

Jan 1, 1981

By G. W. Brownell, H. T. F. Lundberg, R. W. Pringle, K. I. Roulston

The rapid improvement of the airborne scintillometer and the perfection of its efficiency for counting low energy gamma radiation has made it possible to work out a technique to map in great detail the radiation pattern at the earth's surface. On such maps low radiation over certain areas appears to indicate the existence of oil accumulations, forming a pattern similar to that obtained by the geo-chemists. RADIOACTIVE analyses of samples from the surface of oil fields were carried out more than 10 years ago in Alberta by the alpha particle ioniza-tion chamber technique,' but large enough tracts could not be covered in these investigations to make possible any evaluation of the method as a means of oil exploration. Considerable interest has recently been revived, however, as a result of certain striking advances which have been made in the instrumentation available -for the measurement of radioactivity. It is the object of this paper to indicate the nature of these improvements in radiation technology and then to describe the attempts that have been made to interpret the radioactive patterns obtained in the course of airborne recordings with the new instruments. Since the survey can be carried out from the air and records can be accumulated over vast areas in a short time, the result may easily lend itself to statistical treatment. Areas have been surveyed in Alberta, British Columbia, Saskatchewan, Quebec, Texas, New Mexico, Nebraska, Colorado, Utah, and Montana. Producing fields in Alberta and West Texas have been flown over several times in different directions, Fig. 1. The operations were then extended into unknown territory and drill holes were put down on the anomalies which looked promising. The results from these drillings were encouraging and have given hopes for the development of an entirely new method of oil exploration. Any large scale method for the survey of radioactive anomalies must be based on the measurement of gamma rays, as beta and alpha rays have much too short a range to be of any significance. Thus the essential improvement which has made the present stage of this work attainable is the development of new highly sensitive detectors for gamma radiation. In the past the only detectors of any consequence that were available were the ionization chamber and the geiger counter, but both of these suffer from the defect that only a small proportion of the gamma rays passing through the counter are detected, possibly 0.1 to 0.2 pct. The recent development of the scintillation counter2,3 has completely transformed the situation and has had a considerable impact on many branches of nuclear technology. The detection of alpha particles in zinc sulphide screens by visual observation of the individual scintillations which these particles produce dates back to the early spinthariscope of Rutherford and Crookes, but the combined use of an appropriate scintillating phosphor and photomultiplier tube had to await the technical development of the latter many years later. With this development came the modern era of the scintillation counter and a knowledge of phosphors which have a large light output under the bombarding action of gamma radiation. Some of these phosphors are relatively dense and are capable of stopping a large proportion of the incident gamma radiation. As the sensitive region is the whole volume of the crystal, a very high detection efficiency, 50 pct or more, can be obtained for medium energy gamma rays. Scintillation counters for geological purposes were first developed in 19494-6 in an attempt to utilize this remarkable improvement in efficiency, which has the attractive consequence that only a small portion of the normal background of the counter is due to cosmic radiation. In 1949 tests were made in northern Saskatchewan by Lundberg Explorations Ltd. with portable scintillation counters which gave excellent results in the search for uranium and served to indicate unknown uranium deposits in areas previously closely surveyed with geiger counters. Portable scintillometers (registered in Canada) are now commercially available and in regular use,' and the adaptation of the instrument to radioactivity oil well logging has also been very successful.8 Initial attempts to measure radioactivity from aircraft with scintillation counters were made during this period in the same area and yielded most encouraging results. It would be appropriate to consider some specific requirements for airborne investigations. The essential problem to be met in the detection of any radioactive source is the necessity of obtaining a signal greater than the statistical fluctuations of the background counting rate for the instrument. It is possible to show that Nt>2k2 is the condition for detectability of a signal where N = average background counting rate for the detection. t = time constant of the counting rate meter, used to determine the average number of counts arriving in a certain predetermined time interval. N' = average source counting rate at the detector. k = N/N', and N>>N'. Sample values are given in Table I. Assume that the aircraft carrying the equipment is travelling at 120 mph, in which case it will cover 176 ft in 1 sec. Assume also, as a first approximation, that a point source target is in range when the air-

Jan 1, 1954

The Committee on Nominations begs to submit the following names as its nominees for the respective offices indicated: For President, SIDNEY J. JENNINGS, New York. For Vice-Presidents. C. W. GOODALE,* Butte, Mont.; MARK, L. REQUA, San Francisco. For Directors, J. E. JOHNSON, JR., New York; ALLEN H. ROGERS, Boston; HOWARD N. EAVENSON, West Virginia; ROBERT AI. RAYMOND, New York; WILLET G. MILLER, Canada. The nomination for President has attracted the attention of a large number of members, as is evidenced by the receipt of many hundreds of letters and postcards. Most of these favored either Sidney J. Jennings or Philip N. Moore, each of whom received many cordial endorsements. Such a wide interest on the part of the members is a very wholesome sign, but where there is so much activity it is natural to expect a certain amount of criticism. Some of the letters indicate that the authors feel that the nomination of President should be left entirely to the Committee on Nominations without any effort by the members at large to influence them. Others feel that the nominations are largely controlled by a small group and that the members at large can have little influence. As the result; of the experience of the last few months; a majority of the Committee on Nominations begs leave to suggest that the method of making nominations be changed so that two candidates, at least, for the various offices to be nominated, and suggests that the Directors appoint a committee to investigate this question thoroughly with. a view to making definite recommendations. In accordance with its opinion that the best interests of the Institute would be served by a change in the Constitution, allowing the nomination of two candidates, and in view of the fact that this Committee has no authority to make more than a single nomination for each office, considering the high standing of both Mr. Jennings and Mr. Moore and the large number of members favoring each of these gentlemen, this Committee respectfully suggests the desirability of ,the immediate nomination of Philip N. Moore by a petition of 25 members in accordance with the present Constitution. This Committee regrets, its inability to make two nominations. Respectfully submitted, S. W. MUDD, Chairman.

Jan 1, 1917

By E. W. Dewing

The solubility of A14C3 in cryolite melts has been determined by holding the melt with aluminum in a graphite crucible for 4 hr at temperature, quenching the crucible in water, and analyzing the frozen salt by CH4 evolution. The solubility is given by log(wt % Al4C3) = 1.298 -1.l74 (wt ratio NaF/AlF3) independent of temperature in the range 985" to 1080°C. Additions ofA1203, .NaCl, CaF2, or LiF up to 10 wt pct do not affect the solubility, provided that LiF and CaF2 are replaced by equivalent NaFin calculating the ratio. The variation with ratio can be accounted for quantitatively on the hypothesis that the Mechanism of solution is Al4C3 + 2AIF3 = 3Al2CF2 since the solubility varies as (aAIF3) 2/3; Mechanisms involving C", C2- , AlC- , A12C2+, and Al2CF+are re-jected. At ratios above 1.5 truces of c;- are also present. It was noticed some years ago in this laboratory that carbon specimens made cathodic in a cryolite bath decrease in diameter over a period of time.' It was also found that cryolite which had been melted with aluminum in a graphite crucible was sometimes yellow, and that A14C3 could be seen intimately embedded in the cryolite crystals. CH, could be recovered by acid attack. There was thus reason to believe that A14C3 had a genuine solubility in molten cryolite, and the object of this work was to measure it. EXPERIMENTAL AND RESULTS A graphite crucible, 2 in. ID and 2.5 in. deep with a close-fitting lid, contained about 150 g of cryolite (plus additives) and about 20 g of 99.99 pct pure Al. It was placed in a vertical Inconel furnace tube, covered with refractory brick to provide thermal insulation, and the top of the tube was roughly sealed with disks of asbestos paper. An alumina tube led argon down to the level of the top of the crucible to expel air, and an alumina sheath with a Pt-10 pct Rh ther-mocouple inside was positioned between the crucible and the wall of the Inconel tube. The tube was heated in an electrical resistance furnace for the desired length of time; the refractory bricks were then removed, and the crucible was lifted out with tongs and quenched in water. After such a crucible was broken open it could be seen that its inner surface was yellow owing to the presence of A1,C3, and sometimes needle-like crystals could be observed (at X75 magnification) growing out into the nielt. It was concluded that Al,C, had been present as a separate phase when the crucible was at tenlperature and that the melt had been saturated: in

Jan 1, 1970

US 4,137,751-Aerial geophysical exploration for ore deposits by collecting and analyzing atmospheric particulates The aircraft has an Inlet duct extending outward and including a "shave-off" duct, a cyclone separator located inside the cabin which is coupled to the inlet duct, a clean air exhaust duct, and a receiver for the collected particles incoming air is divided into two fractions. The fraction taken by the "shave-off" duct and containing the bulk of the particles is routed to the cyclone Particulates are gathered on a collector tape for subsequent analysis and correlation with the areas covered J. R Rhodes, R D. Sieberg, M. C Taylor, J. C Westkaemper, and R C. Young, assigned to Columbia Scientific Industries, Inc Feb. 6, 1979 7 pp. (73-28) Filed- 2-28-75 (554,114) Same British 1,446,760, dated Aug. 18, 1976. US 4,156,138-Exploration for subsurface deposits of uranium ore Pairs of dosimeters are placed underground in a grid pattern Each dosimeter contains a phosphor which IS capable of storing the energy of alpha particles. One dosimeter is heavily shielded from alpha particles, while the other in the pair is thinly shielded to exclude dust After a period underground the dosimeters are heated to release the stored energy as light. The amount of light produced from the heavily shielded dosimeter is subtracted from the amount of light produced from the thinly shielded dosimeter to give an indication of the location and quantity of uranium underground This patent is a division of US Patent No 4,053,772, dated Oct 11, 1977 P E Felice, assigned to Westinghouse Electric Corp May 22, 1979 5 pp (250-253) Filed. 8-12-77 (824,203) US 4,180,727-Method for measuring the gamma-gamma density of uranium ore in the vicinity of a borehole A first gamma-ray detector receives only natural gamma rays from the borehole, while a second receives both natural gamma rays and scattered uranium-source gamma rays The value of the uranium-source gamma rays is calculated. W W Givens, assigned to Mob11 011 Corp Dec 25, 1979 6 pp (250- 264) Filed 10-20-77 (843,909) US 4,180,72&A neutron activation probe for determining the location and grade of uranium ore, especially where thorium or other fissionable isotopes are present, includes a pulsed neutron source in series with a plurality of delayed neutron reactors for measuring radioactivity in a well bore- hole together with a Nal(T1) counter for measuring the high energy 2 62 MeV gamma line from thorium The signal from the Nal(T1) counter IS subtracted from the signal from the delayed source detectors to ascertain the amount of uranium present in the ore body N. P Goldstein and R C Smith, assigned to Westinghouse Electric Corp Dec 25,1979 6 pp (250-264) Filed. 4-1 1-78 (895,323)

Jan 1, 1980

By T. S. Lundy, R. E. Pawel

Effects of short-circuiting paths on observed diffusion behavior in real crystalline systems are considered. It is concluded that experimentally measured diffusion coefficients may vary widely from values associated with true lattice diffusion to those appropriate for short-circuiting paths alone depending upon the conditions of the experiment and the sensitivity and completeness of the data. IN 1961 Harrison1 classified experimentally observed diffusion behavior in systems involving both lattice and dislocation-enhanced atomic transport into three categories. His types A and C were limiting cases where the measured diffusion coefficients using the usual serial sectioning techniques were representative of lattice diffusion (with only slight effects of dislocations) and dislocation-network diffusion (with only slight effects from lattice diffusion), respectively. In both cases A and C for a sectioning experiment in which the diffusion couple has the semi-infinite geometry and unidirectional diffusion takes place from a plane source located at the origin of the coordinate system, he pointed out that Gaussian penetration behavior should be observed. For case A the lattice coefficient should be slightly enhanced by dislocation contributions, and the model of Hart2 can be used to predict the amount of this enhancement. For case C the observed coefficient should be that for the dislocation network and have little or nothing to do with lattice diffusion. Hart's model in its general form is still applicable, but the apparent diffusion coefficient for this case is virtually independent of dislocation density. Harrison's case B is that for which non-negligible contributions exist for transport by both mechanisms and "the concentration distribution does not approximate to any simple form." With the possible exception of very low temperatures where diffusion distances approach atomic dimensions, any real diffusion specimen will in general show non-Gaussian behavior provided the data are complete enough to uncover it. Thus, a "complete" set of data for any real system cannot be expected to be totally amenable to treatment by a simple mathematical model which does not take into account the relative distribution of transport by the various modes or submodes. For a particular sensitivity of specimen analysis and at a given temperature of annealing if the concentration profile could be observed as a function of time, "the behavior will initially be type C, and will develop into type B. and ultimately type A".1 Thus, it appears that the type of diffusion behavior which is experimentally observed in a given system depends very much upon the particular experimental conditions and the particular tools available to obtain the data. Interpreted in this fashion, Harrison's classification refers not to the diffusion behavior as a whole but to the relative sensitivity of the method of examination and completeness of the data. In the present paper we will: 1) assume that the measured penetration behavior follows the same general classification as that proposed by Harrison; 2) give, for diffusion in tungsten, examples of the range of diffusion coefficients that it is possible to obtain in a single experiment; and 3) speculate that some arguments which consider the possibility of short-circuiting effects being responsible for "anomalous" diffusion in several bcc metals may have been discarded prematurely.3 Both monocrystalline and polycrystalline tungsten were used in this work. The former was obtained as triple-pass, electron-beam zone-refined 6.0-mm-diam rod from Materials Research Corp.. Orange-burg. N.Y. The latter was swaged, high-purity bar stock which was annealed for 2 hr at 2200°C and 10-9 torr to yield an average grain diameter of about 25 /i. The tracer Nb95 was received in oxalate solution from the Isotopes Division, Oak Ridge National Laboratory. Experimental procedures of specimen preparation, isothermal diffusion annealing, serial sectioning by anodizing-and-stripping, and y counting of the individual sections to determine the tracer penetration profile after a given diffusion anneal have been described elsewhere.4 However, it should be noted that the anodizing-stripping sectioning technique has the particular advantage for this research of permitting sectioning to be accomplished over a wide range of

Jan 1, 1970

GENTLEMEN: Submitted herewith are the report of the Treasurer for the year 1940 and reports for the same year of the following standing committees: Admissions, Membership, Pa¬pers and Publications, Mining and Metal¬lurgy (Magazine), Library, and Student Relations. These reports present additional details. MEMBERSHIP For the third year in succession member¬ship reached a new high level for all time, as indicated in the accompanying tabula¬tion in which "Members" includes all categories except Student Associates.

Jan 1, 1941

By Renato G. Bautista, KNona C. Liddell

A model of the reaction of chalcopyrite, CuFeS2, with Fe3+ and with 02 is considered. Homogeneous solution phase reactions are assumed to be always at equilibrium throughout the dissolution of the mineral. The dissociation of USOb- and several complexation reactions involving cu2+, Fez+ and Fe3+ are incorporated in the model equations. The relative importance of Fe3+, 02, and H+ as oxidants and the role of solution equilibria are assessed and the implications for leaching practice discussed.

Jan 1, 1981

By C. Williams, D. V. Carter

During 1943 five oil fields and two gas-condensate fields were discovered in the East and East Central Texas district. The New Hope field, discovered by Tide Water-Seaboard in Franklin County, is the most important oil discovery since the Hawkins field in 1940. At the close of the year two oil sands were producing and two additional oil sands were being tested. The gas-condensate fields of Appleby in Nacog-doches County and the Stewards Mill field in Freestone County had only one producing well each. The Carthage field was extended 3 miles north and 4 miles west. Another well that was testing at the year end indicated a probable eastward extension of several miles. The Quitman field, in Wood County, was the most active from the standpoint of drilling operations. Approximately 48 wells were complcted during the year. The second and third most active fields were Hawkins field, Wood County, and Kildare field, Cass County, respectively. Wartime restrictions of material, together with manpower shortage and Federal spacing regulations, reduced the number of oil and gas-well completions from 265 in I942 to 171 in 1943. This represents a drop of 35 percent, or approximately 1/3, enough to replace the 531 producing wells abandoned in the district during the year. No changes were made in the price of crude oil in the district in 1943. The district produced 177,652,940 bbl. of condensate and oil during 1943. This represents an increase of approximately 11 per cent compared with the previous year. The East Texas field, which is the largest and most important field in the district, had an annual production of 128,568,647 bbl. of oil, which is approximately 6.5 per cent more than the previous year, and represents 72 per cent of the district's production of condensate and oil for the year. The district had an estimated basic daily allowable of approximately 509,000 bbl. of oil on Dec. 31, 1943. The entire district produced approximately 30 pcr cent of the state's production for the year 1943. The Hawkins field, Wood County, was operated 271 days during the year and with an average daily production of approximately 52,488 bbl. for the year. This field, which is the second largest in the district, produced 14,224,164 bbl, of oil during the year. Changes in annual production in certain fields in the district can be attributed to their ability to produce at higher rates, the demand, and transportation facilities in the war effort. The East Texas field showed an over-all decrease in reservoir pressure of 8.30 lb. during the year. Indications were that through the first quarter of 1944 the return of salt water to the reservoir was having a beneficial effect. It is hoped that, as more and more water is returned to the reser-

Jan 1, 1944

By D. V. Carter, C. Williams

During 1943 five oil fields and two gas-condensate fields were discovered in the East and East Central Texas district. The New Hope field, discovered by Tide Water-Seaboard in Franklin County, is the most important oil discovery since the Hawkins field in 1940. At the close of the year two oil sands were producing and two additional oil sands were being tested. The gas-condensate fields of Appleby in Nacog-doches County and the Stewards Mill field in Freestone County had only one producing well each. The Carthage field was extended 3 miles north and 4 miles west. Another well that was testing at the year end indicated a probable eastward extension of several miles. The Quitman field, in Wood County, was the most active from the standpoint of drilling operations. Approximately 48 wells were complcted during the year. The second and third most active fields were Hawkins field, Wood County, and Kildare field, Cass County, respectively. Wartime restrictions of material, together with manpower shortage and Federal spacing regulations, reduced the number of oil and gas-well completions from 265 in I942 to 171 in 1943. This represents a drop of 35 percent, or approximately 1/3, enough to replace the 531 producing wells abandoned in the district during the year. No changes were made in the price of crude oil in the district in 1943. The district produced 177,652,940 bbl. of condensate and oil during 1943. This represents an increase of approximately 11 per cent compared with the previous year. The East Texas field, which is the largest and most important field in the district, had an annual production of 128,568,647 bbl. of oil, which is approximately 6.5 per cent more than the previous year, and represents 72 per cent of the district's production of condensate and oil for the year. The district had an estimated basic daily allowable of approximately 509,000 bbl. of oil on Dec. 31, 1943. The entire district produced approximately 30 pcr cent of the state's production for the year 1943. The Hawkins field, Wood County, was operated 271 days during the year and with an average daily production of approximately 52,488 bbl. for the year. This field, which is the second largest in the district, produced 14,224,164 bbl, of oil during the year. Changes in annual production in certain fields in the district can be attributed to their ability to produce at higher rates, the demand, and transportation facilities in the war effort. The East Texas field showed an over-all decrease in reservoir pressure of 8.30 lb. during the year. Indications were that through the first quarter of 1944 the return of salt water to the reservoir was having a beneficial effect. It is hoped that, as more and more water is returned to the reser-

Jan 1, 1944

By Nicholas J. Grant, H. C. Chang

EMPHASIS on the importance of grain boundary sliding as a mode of deformation at elevated temperatures has been presented elsewhere.' The extent to which boundary sliding occurs under certain creep conditions has been determined for high purity aluminum2,3 and aluminum alloys.' In general, boundary deformation extends quite far into the adjoining grains, resulting in a rather wide band of deformation along the grain boundaries. This has led some investigators to doubt that grain boundary sliding consists of shearing along the boundary surface; it has been contended instead that boundary sliding is a result of concentrated slip in the neighborhood of the deformed grain boundaries."' The purpose of this note is to present evidence that grain boundary sliding takes place by a bulk shear process. gh purity polycrystalline aluminum, wherever and whenever there is grain boundary sliding, boundary migration and concentrated deformation along both sides of the deformed boundary are associated with it. Therefore, it has been rather difficult to obtain unambiguous evidence of boundary sliding. On the other hand, it would be expected in certain alloys of aluminum, when tested under particular conditions. that the severity of the interfering effects of boundary migration and concentrated deformation along the deformed boundary might be reduced. Current research in this laboratory' shows that a 20 pct Zn-A1 solid solution alloy fractures in an intercrystalline manner during creep at 500°F with a small total elongation of not more than about 14 pct, and that it does so with extremely limited grain boundary migration. Accordingly, this alloy was chosen for the present study. The experimental procedure was similar to that used in previous work and has been presented elsewhere.' Two parallel flat surfaces were milled from a round specimen. The gage portion of the specimen was 1 in. x .09 in. x .17 in. The specimens, which were annealed at 1030°F for 24 hr, showed two to four grains across the width of the test bar. The specimens were subjected to creep at 500°F at stresses of 2000 to 5000 psi. The rupture times were from 10 sec to 3 hr. Appreciable boundary sliding occurred in all the tests. A typical example of boundary sliding is shown in Fig. 1. (The tension axis is vertical in the micrographs.) Sliding has taken place along the boundary between grains A and B unaccompanied by important boundary migration. The sharpness of the offset at the triple point can be clearly seen in grain C. As a result of sliding along the boundary between grains A and B, a new boundary surface between grains A and C was created. The offset at the triple point is about 0.07 mm. This boundary sliding is accompanied by the formation of rather sharp kinking bands and, of course, slip on several slip systems in grain C. This type of deformation has been referred to as fold formation' in previous work with high purity aluminum.

Jan 1, 1957

By J. M. Oblak, W. A. Owczarski

A cellular appearing recrystallization product formed by annealing a cold-worked nickel-base super-alloy at 1800°F has been studied by electron nzicroscopy. Prior to deformation, an equilibrium micro-structure of fcc matrix y and cuboidal ,,', Ni (Al, Ti), precipitates of CuzAu structure had been established by an age at 1825°F. The strain-free recrystallization cells consist of very large rodular y' particles in a y matrix. They precipitate is oriented and coherent both before and after recrystallization. The results showed that y' coarsening accompanies recrystallization at 1800°F. However, it does so as a secondary effect and does not necessarily take place at lower temperatures. The structural similarity of this reaction to cellular precipitation in other systems indicates that lattice strain may also play a significant role during some cellular precipitation reactions. THERE have been numerous microstructural investigations of recrystallization in single-phase materials but two-phase systems have received much less attention. The second phase can either remain inert or be altered along with the matrix during recrystallization. If the second phase is an oxidelm3 or a relatively inert pre~ipitate,~, recrystallization is retarded when the interparticle spacing is less than 1 p. Prior to the onset of recrystallization, these materials show a well-polygonized substructure with the subgrain size limited by the interparticle spacing. Since recrystallization by the motion of preexisting grain boundaries6 is not observed, retardation has been related to particle pinning of the subboundaries. This pinning prevents coalescence' or growth8 of subgrains to a critical size (formation of a high-angle boundary) necessary to initiate recrystallization. In a material such as a nickel-base superalloy both y matrix and y' precipitate are altered by the recrystallization reaction. Haessner et al.' studied the recrystallization of a cold-rolled Ni-Cr-A1 alloy by electron microscopy. The material was initially cold-rolled in the supersaturated condition. upon annealing at 750°C, immediate precipitation of 7'occurred. Presence of this 7' greatly retarded the onset of recrystallization which eventually took place by the development of randomly oriented, strain-free grains. The original •/ was dissolved at the recrystallization interface and reprecipitated as oriented, coherent par-tiles in the new grain. Recrystallization caused a refinement of .)' particle size. Recently ~hillips'' investigated recrystallization of Ni-12.7 at. pct Al. Reduction by cold rolling presumably elongated the p' precipitate into lamellae that remained coherent with the matrix. After recrystallization at 600" to 750°C, there was no unusual change in y' particle size al- though there was a tendency toward clustering along the prior rolling direction at 750°C. Above 750°C, the recrystallized grains were generally free of precipitate. Studies in the somewhat analogous Cu-3.23 wt pct CO" and Cu-2 wt pct'2 systems demonstrated that the coherent cobalt-rich fcc precipitate in these alloys obstructed softening, initiation, and completion of recrystallization. The precipitates were deformed into lam~llae during rolling and those of diameter less than 250A remained coherent. Recrystallization took place by the growth of new grains into the recovered or poly-gonized material. In the first study," both matrix and precipitate reoriented in the same manner upon passage of the recrystallization interface. There was no change in particle size or morphology. Tanner and ~ervi,~ on the other hand, observed that motion of the recrystallization fronts was strongly hindered by the pinning action of coherent precipitates in the deformed material. Particles in contact with a pinned boundary coarsened and coalesced leaving a denuded zone in the unrecrystallized region. When the number of pinning points was sufficiently reduced by coalescence, the boundary swept past these particles and through the denuded zone. The authors1' considered this as a variation of discontinuous precipitation with both chemical driving force and deformation strain energy contributing to recrystallization. Preliminary observations by the present authors had revealed that recrystallization in Udimet 700, a nickel-base superalloy, occurred in an entirely different manner. Optical metallography showed that the recrystallized product formed as cellular colonies containing coarse y' particles elongated in the direction of cell growth. In this investigation the structural features of this reaction were investigated by transmission electron microscopy. EXPERIMENTAL PROCEDURE As-received I$-in. rounds of Udimet 700* were (wtpct) 18.4 15.2 4.95 4.42 3.43 0.06 0.031 0.14 Bal. solution-annealed for 4 hr at 2150" and then fast air-cooled. An initial y-~' structure was established by a 4-hr age at 1825°F followed by a fast air,cool. Essentially the equilibrium volume fraction of ?' at 1825°F is precipitated within 4 hr. Microstructural examination showed no measurable increase in the amount of precipitate after longer aging times. Deformation consisted of swaging to 52 pct RA with 6 pct reduction per pass at room temperature. To reduce the precipitation potential to a negligible amount, recrystallization anneals were conducted at 1800"~ (982"~). Microstructures were investigated by optical and transmission electron microscopy. To prepare foils for electron microscopy, the material was first sliced into 30-mil slabs parallel to the swaging direction. Discs were dimpled and electrolytically cut from

Jan 1, 1969

THERE are many kinds and varieties of earth* that are used for the loam compositions for making the moulds for casting bronze, brass, or other metals. Since this is a very necessary thing, you must try to have the best kind and one that resists the fire well. It must be disposed to receive the metals well, must make a neat casting, and must not shrink or break with cracks on drying or baking. Aside from actual trial, I believe that there is little that can help you, since the clay in itself has no color or [77] visible sign that I know of to show how satisfactory it is. Understand that their colors are no less varied than their natures, for, as you see, one is white, one black, one yellow, and another red. Perhaps none will show by its color that it is good for this work, yet it might also happen that all colors are good. But all that I can say about it is to show you by their effects how the good ones should be in their nature; and so by trial you will choose among those that come into your hands. All earths are either sandy or tufaceous, either argillaceous and lean or pasty with unctuous viscosity. The lean ones make the loam powdery and without toughness and hold together poorly by themselves when they are dry. The unctuous and viscous ones shrink and break. Becoming smaller by shrinking, they often twist the forms and they stick together badly. They swell up again in the fire and produce works that are neither exact-a nor neat. Therefore, the good ones must be those that are neither unctuous nor lean, neither wholly tender nor rough, and with a grain that is fine, without pebbles or shells. When applied to a work they easily dry out without fractures and, when dry, hold their own shape well. Above all they must resist the fire well. These are usually of a yellow or red color, but whatever their color may be, the color does not force me to say that the yellow are really better than the black, and the red than the white or gray. Their quality depends on what trial shows. Thus, to summarize, whenever you have to do this work, you must try to have the best clay that you can, because it is to be the foundation of

Jan 1, 1942

By Hermsdorf, Richard P. E.

AMONG the newer lead smelting and refining plants of the country is that of the United States Metals Refining Co., at Carteret, N. J. Not only is the technical practice here modern and efficient, but exceptional care is taken to assure healthful operating conditions for the employees. One large building houses the entire department, which includes, as its chief units, one reverberatory smelting furnace, one blast furnace, two softening furnaces, one utility reverberatory furnace, two Faber du Faur retorts, five 120-ton kettles, three 60-ton antimouial lead kettles, and one 5-ton kettle for experimental purposes. There is a 10-ton overhead crane in the kettle aisle, which is also used for shipping lead. Other auxiliary equipment is referred to in the outline of operations. A general plan of the plant is shown in Fig. 2, and a general view in Fig. 1. Primary smelting operations are conducted in a 30 by 11-ft. reverberatory furnace with bottom, roof, and upper walls of clay brick, magnesite

Jan 1, 1934

By F. X. Tartaron

The comparison of actual energy of comminution with theoretical surface energy presents a wide gap. On the other hand, Solid State Theory presents a viewpoint that places actual energy of breakage in understandable relationship with the theoretical strength of materials. Therefore the physical background of comminution theory favors Kick's Law. A11 discussions of comminution theory appear farfetched when comparison is made of the actual energy of crushing with the energy input called for by thermodynamic theory. Quoting Taggart:' "The work required to crush halite was of the general order of 0.10 kg cm per sq cm of new surface produced (based on air percolation) whereas the theoretical energy of this new surface, based on thermodynamic calculation by a number of investigators is 1 x 10'4 kg cm per sq cm or the work expended was 1000 times the new surface energy — an indicated crushing efficiency of 0.10 pct." It is frustrating to probe into comminution theory with the prospect that the energy one is measuring is 99.9 pct waste energy. Do the laws of comminution deal with energy consumed by mineral breakage or with waste heat energy? There seems to be something wrong. Solid State Theory may provide the answer. The following statement is particularly apt to the situation: "The fundamental fact about metals and indeed all materials, is that they are much weaker than they should be. By this, we mean that if the stress required to cause a given plane of atoms to slip past a neighboring plane is calculated from basic atomic and Solid State Theory, the resulting number is some 1000 times too large to be accounted for by errors in approximations or assumptions. We know now that this is due to dislocations, and we even have a fair understanding of the details of the process by which dislocations make a crystal weak. An intriguing possibility which suggests itself, results from the discovery of very minute metallic crystals which are apparently free of dislocations and which have a strength approaching the ideal value for a perfect crystal." Here we have an extraordinary reversal of the situation. The actual energy for breakage is only one-thousandth the theoretical instead of 1000 times as given by Taggart. But the theoretical energy presented by Solid State Theory is the binding energy between atoms (or ions) in a crystal lattice. This is the kind of energy envisaged by Kick's law. The surface energy or the other hand corresponds to Rittinger's law. Comparison of theoretical with actual, on the basis of surface or on the basis of Rittinger's law, seems to present an absurdity; yet Rittinger's law is confirmed by an impressive array of experimental evidence. Comparison of theoretical and actual on the basis of Solid State Theory or, in other words, on the basis of Kick's law seems reasonable; yet there is not a scrap of evidence to verify Kick's law. The situation appears paradoxical, but the developments in the next section of this paper show that the paradox is a hint to a strange turn of events. ENERGY-WEIGHT FRACTION FUNCTION charles3 has presented a final equation showing the relation of energy consumed in comminution to size of product n{-1) a-n + 1 E is energy, C is proportionality constant, a and n are constants and k is the coarsest size in the ground product (size modulus). In the course of study of a large amount of experimental evidence, Charles discovered that in the general case, a-n + 1 approximated zero. For some reason, a and n differed only by unity. But if a—n + 1 = 0 within experimental error, then it is obvious that Eq. 1 states that it requires an infinite amount of energy to grind any sample to any size. This is a case where nature gives an absurd answer to a man-made mathematical equation, hence something is wrong with the equation. An adjustment must be made to fit the equation with experience. TO reveal the nature of the adjustment, the differential equation preceding the second integration in Charles' group of equations is given When Charles integrated the quantity xa-n it was almost impossible for him to realize that he was dealing with a special case of integration and that

Jan 1, 1962

By J. W. Axelson, J. N. S. Kwong, J. T. Adams, E. L. Pire, J. F. Johnson

CRUSHING has always been a major operation in the chemical and metallurgical industries, yet little is known about the theory of crushing, and today, the design of crushers is still based almost entirely on empirical knowledge and accumulated practical experience. In view of the increasing national need for the economic working of poorer grades of ores, the lack of a fundamental understanding of this unit operation hardly presents a satisfactory situation. Basic investigations of crushing have been concerned mainly with three phases of the problem, 1—the mechanism of the fracture process itself, 2— the particle size distribution of the crushed product, and 3—the relationship between the energy input and the amount of new surface produced. Probably adequate information on these phases will be required for a comprehensive understanding of the process of crushing. A bibliography covering these phases will be given as well as a review of the work done in recent years at the University of Minnesota on the relationship between the energy input for crushing and the amount of new surface produced. Fracture of Solids This phase of the crushing problem is the most fundamental because it is concerned with the actual mechanism of fracture. The main problems in a study of the fracture process are concerned with the questions of why and how fracture occurs and why there is such a discrepancy between the actual and theoretical energies needed in a fracture process. In considering the how of fracture, Poncelet40 carried Out experiments On the crushing of glass under compression. Actual photographs were taken of the glass plates in various stages of fracture-From these experiments Poncelet was able to postulate a probable mechanism of fracture. Probably because of the quantitative nature of the problem, considerable effort has been expended to find an explanation for the low tensile strength of materials and the conversely high energy for crushing. Tensile strengths are often only 1/500 of the theoretical while the energy for crushing is usually at least 500 times the theoretical. A review of the work to explain the low strength of glass is given by Weyl,52 in which the work of Griffith," Joffe,32 and Powell and Preston " are discussed. In a recent paper Seitz46 holds that the presence of flaws and fissures, as originally expounded by Griffith, is the most probable reason for the low strength of metals. Since a mass of data has been accumulated on the fracture strength of materials, several investigators have attempted to correlate this data in the form of an equation. Glathart and Preston," Taylor,40 Ponce-let,40 Machlin and Norwich," and Frederickson and Eyring,20 have all considered this problem, and the final relationship has always been that the stress for fracture is proportional to the logarithm of time. Murgatroyd30 arrived at a very similar relationship by a different method. The study of the fracture process has used many methods. Among some of these are the thermody-namic approach used by Furth21 which was based on the work of BornxL and later used by Saibel,43 and the statistical method applied by Fisher and Hollo-mon.10 In recent years metallurgists have concerned themselves with the problem of brittle .fracture as opposed to the usual plastic failure of metals. The great amount of interest shown is reflected by the number of contributors to the recent symposium on the fracture of metals.' Repeated failures of welded ships during World War II have accelerated these Studies.31,50,34 The shifting of thought from an emphasis on the

Jan 1, 1952