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By Olaf Hondrum

CHURN drilling equipment at Bagdad consists of two Bucyrus Erie 27-T model drills and one 22-T drill with gasoline engines. The drilling tools weigh approximately 1600 lb. The holes are drilled with 7-in. bits which are heated in an oil burning furnace and sharpened in an electrically powered bit sharpener. A service truck brings the bits to the drills and takes the dull bits back to the shop. The bits weigh around 250 lb. when new and are handled by drill crews without any mechanical handling device. When the management decided to start open- pit operations in 1945 the ruggedness of the terrain was one factor that led to the purchase of the small 22-T model drill. The orebody lies on both sides of Copper Creek Canyon. The sides of the canyon are steep and are cut by numerous narrow branch gullies. The drill had to travel over roads that were narrow and steep. It proved adequate for drilling the capping formation and is still in use.

Jan 1, 1950

By W. B. Wise, H. D. Attra, W. M. Black

The purpose of this paper is to illustrate a comparatively new approach for solving a problem that has plagued oil producers for many years—how to make the most money with available field production capacity. In a very basic operation such as a top-allowable one-well field, a computer and staff of engineers are not required to determine that the best operation is to produce that well at its maximum for as long a time as it will produce. However, as the problem becomes more complex and the number of wells and number of reservoirs increase, it probably will be a wise choice to devote some engineering thought and calculation time to determine the best way to operate that field on both an ultimate and day-to-day basis. Continued developments in the field broadly referred to as "operations research" have led to a number of useful engineering analyses for optimizing field operational problems. One of these techniques, termed linear programing, is parlicularly interesting because of its potential applications to the study of complex oilfield operating problems. Linear programing is concerned with the problem of planning a complex set of interde~endenl activities in the best possible (optimal) fashion. A field application of linear programing is being used to maximize daily income from a multi-reservoir producing operation. The initial results of this study indicate that the linear programing technique (I) can be applied effectively to field problems, (2) can be used to detect unsuspected avenues for improving operations and (3) can effect a significantly improved means of controlling field operations through the use of the highspeed computer. INTRODUCTION The usual approach for studying complex field operational problems has been to look in detail at several basic plans suggested by judgement and experience and, then, to choose the best plan from those investigated. This approach is entirely satisfactory provided: (1) that judgment and experience alone will reliably pick the best or near the best program as one of the plans to be investigated; and (2), and most important, that the factors which control field production will not change. This paper deals with the large group of field operations which are at least one-step removed from a satisfactory solution using the conventional method of analysis. Problems such as pipeline- and gathering-system design, transportation studies, large field development projects and multi-reservoir producing operations fall in this latter category. To find the best program for handling these problems when the best program is not obvious, a complete optimization study is required, and high-speed computers are required to continually update the program once it is selected. Operations of this type have an extremely large number of possible solutions. However, only one will result in maximum economic return and, more important, this one program must be re-evaluated and adjusted constantly to accomodate such changing field factors as the number of producing days, the price of crude, the discovery of new reserves, declining reservoir pressure with subsequent decline in production and a host of other factors which characterize specific operations. One of the most widely used, direct methods of optimization is a numerical procedure termed "linear programing", which is designed to investigate systematically each of the possible solutions involved in a given problem, determining rapidly and uniquely the optimum answer. As implied by the name, linear programing requires that all field variables be either defined or expressed in a series of interdependent linear equalities or inequalities. These relationships are solved simultaneously, using a form of matrix solutions to determine the optimum values for each producing variable that will maximize net profits. The solution techniques used in a recent field case study is termed the "simplex method" and is discussed in full detail in Ref. 1.

By Lewis T. Wright

(Pittsburg Meeting, March, 1910.) I HAVE long been aware that ferruginous copper furnace slags if fused in the electric arc will yield metallic iron containing copper, and in order to confirm this knowledge, and to obtain further information of the behavior of such slags in the high temperature and reducing conditions of the electric furnace, a number of samples of slag were fused in an experimental electric furnace. The results obtained, given in Table I., show that a very large amount of metallic iron was produced, and that this iron carried with it practically all the copper, gold, and silver, and more than 50 per cent. of the sulphur, of the original slag. The metallic buttons formed in the electric furnace were clean, hard, but not brittle.

Mar 1, 1910

H. D. HIBBARD, Plainfield, N. J. (written discussion *).-While this valuable and timely paper may not go to the root of the matter, it deals with many of the elements and factors involved. It might be taken as the engineer's solution of the case, starting with the assumption that steel is steel, while the tendency for a rail to have transverse fissures may, and probably does, depend, in part at least, on conditions met before it reaches the track. Admitting with the author that "brittleness of fracture in all grades of steel is characteristic of fatigue tests" we may yet look farther back to find out, if possible, why some rails and some steels are more prone to have transverse fissures than others, for it has been found that rails from certain heats of steel developed these fissures under a service which

Jan 3, 1918

By B. C. Allen

Grain boundary grooving has been studied in chromium, molybdenum, and tungsten under a variety of conditions using high vacuum techniques and tantalum -gettered argon. The average surface free energy of solid chromium, and the chromium-liquid silver interface free energy were respectively found to be 2200 ± 250 and 500 i 130 ergs per sq cm from groove formation kinetics and estimates of pertinent volume difffusion coefficients. The results for chromium were unffected by variations in interstitial content ranging from 0.003 to 0.09 pct C, or 0.003 to 0.03 pct O. Surface diffusion is the primary mechanism of groove formation in chromium under 1 atm argon at 1200" to 140O°C, and is essentially unaffected by 0.003 to 0.09 pct C, 0.003 to 0.03 pct O , metastable nitrogen contents up to -0.01 pct, and up to 2 torr Ag vapor. At higher temperatures, the major mechanism is volume diffusion in argon or evaporation-condensation in stutic vacuum. Surface diffusion occurs in molybdenum at 0.5 to 0.96 and in tungsten at 0.5 to 0.9 of the absolute melting tempera -ture by a single mechanism, possibly by the migration of single adatoms or vacancies. Results were slightly affected by up to 23 tory Sn vapor, and in molybdenum were essentially unaffected by 0.5 Ti or carbon in the range 0.002 to 0.02 pct. Volume difffusion through the liquid is the mechanism of groove formation in chromium-liquid silver at 1200" to 1400°C and in molybdenum-, Mo-0.5Ti-, and tungsten-liquid tin at 1200" to 2000°C. The solid-liquid interface free energies involved were estimated from grooving kanetics. WHEN a grain boundary intersects a solid surface, a groove tends to form along the line of intersection at temperatures above about half the absolute melting point (0.5 TM). The groove progressively grows by preferential atomic migration either by diffusion or evaporation. Establishment of a groove angle occurs in accordance with the grain boundary and surface free energies involved. The motivation for groove formation is a reduction in the total surface free energy of the system. This study is a continuation of previous work on thermal grooving of chromium, molybdenum, and tungsten.&apos; The temperature ranges were extended, and the effect of metallic and interstitial impurities was evaluated. The results were such that certain interface free energies and surface self-diffusion coefficients were deduced from the grooving kinetics. EXPERIMENTAL WORK Materials and Preparation. As indicated in Table I, the 0.05-0.08-cm-thick chromium, molybdenum, and tungsten sheet used was nominally 99.99 pct after recrystallization. Two lots of molybdenum with about the same analysis, Mo-0.5Ti,* and tungsten were ob- *Alloy compsitions are expressed in weight percent . tained commercially. Extruded chromium rod,&apos; prepared from iodide process crystals, was warm rolled to sheet at 700°C. Sheet of three Cr-0 impurity alloys containing up to 0.03 pct 0 was prepared by warm rolling arc melted, extruded, and swaged rod. Two Cr-C impurity alloys containing up to 0.09 pct C were made by equilibrating unalloyed chromium with a known amount of CH4 for 24 hr at 1150°C in previously evacuated quartz capsules. Chromium containing nominally 0.015 and 0.06 pct N was similarly prepared by equilibration with NH3. The sheet was recrystallized to give a stable grain size about equal to the sheet thickness. Molybdenum and Mo-O.5Ti were recrystallized in a tantalum resistance furnace 1 hr at 1 x lo-5 torr at 2300" and 220O°C, respectively. Tungsten was similarly annealed for 1 hr at 2500°C. Chromium and its impurity alloys were outgassed at 1100°C and recrystallized 1 hr at 1700°C under 1 atm Ar. Except for nitrogen, the impurity content stayed roughly constant. Nitrogen in both alloys was reduced to <0.001 pct. In fact, over 80 pct of the added nitrogen was lost after outgassing at llOO°C and annealing sheet 1 hr at 1300°C in argon in the presence of tantalum. Such a rapid loss can be rationalized since -2 torr N are required for equilibrium with 0.04 pct N in solution,3 while the equilibrium pressure is ~10-5 torr over tantalum at 1300°C.4 The recrystallized sheet was cut into small coupons which were metallographically ground and polished on one side with a minimum of grain boundary relief. The surface roughness was on the order of 0.01 µ. The tin and silver used were nominally 99.999 spec-trographically pure. After being outgassed at 1100°C and equilibrated in a molybdenum crucible for 0.5 hr at 1800°C in argon, the tin contained 3 ppm 0, <0.3 ppm N, and 0.1 ppm H. Following outgassing at 900°C and equilibration in a chromium crucible 1 hr at 1400°C in argon, the gas content of the silver was 1 ppm O, <0.5 ppm N, and 0.3 ppm H. Grooving Under Argon or Vacuum. All specimens were placed in unsealed containers made from rod or sheet of the same alloy, thereby enabling the polished surface to achieve gas-solid equilibrium. The annealing fixtures are shown in Fig. 1. The specimen was placed in a resistance furnace with a tantalum or Ta-10W heating element plus tantalum fixtures or radiation shields. Chromium was outgassed at 1100°C, and molybdenum and tungsten were outgassed at 1900°C to 1 x l0-5 torr or at the grooving temperature, whichever was lower. In vacuum anneals, the specimen was then heated directly to the intended grooving temperature. In argon anneals, 99.996 Ar was admitted

Jan 1, 1970

The petition for the formation of a Tulsa Section was granted. The final budget for the year 1917, and the tentative budget for the year 1918, were adopted. The Secretary was instructed to continue to send the Bulletin to all members whose dues have been remitted on account of their being in the war service, but to hold the Transactions and send them on request to the address furnished for the purpose. The issues of the Bulletin were presented to the Federal Fuel Administration, at its request, with the compliments of the Institute. Fifty-nine Members, five Associates, and fifteen Junior Members were elected. The resignation of one member was accepted. The clues of four members who are on active duty at the front were remitted. An extension of time for the payment of clues was granted to four members, upon request.

Jan 2, 1918

(Under this heading will be published notes sent to the Secretary of the Institute by members or other persons.) Mine and mill accountant for Mexico. Knowledge of Spanish desirable. Salary $150 to $200 gold per month with living quarters. No. 60. Master mechanic familiar with mine and cyanide plant machinery for Mexico; $200 gold per month and living quarters. No. 61. Electro-metallurgist for production of ferro-alloys, salary $200 to $400 depending on experience. No. 62. Man familiar with ferro-tungsten products of electric furnaces to draw up specifications for machine tools, to watch these tools in service and revise specifications accordingly. Salary $150 to $200 per month. No. 63. Engineers under 35 years of age for placer mining work in Belgian Congo; $1,500 to $1,700 plus traveling and living expenses, two years&apos; contract. No. 67.

Jan 2, 1916

By Persifor Frazer

The accompanying diagrams represent a lamp provided with certain improvements which render it more serviceable for the use of the engineer or other mining official who is often compelled to visit several mines a day remote from each other, and may be called on to use the magnetic needle in any or all of them. These requirements demand that the material of which it is made should be copper, and that it should be capable of being closed oiltight, for emptying and refilling the lamp at each mine would be a less expeditious as well as a less cleanly process, and transporting a lamp of the ordinary kind over rough roads on horseback or in wagon, would result in spilling the greater part of its contents. The general form of the lamp, including the false back to keep

Jan 1, 1882

By R. R. French

Investigations were conducted by the lndiana Geological Survey for some dry methods of bene-ficiating low-grade gypsum ore. Seventy-two batch and continuous flow tests were performed with a roller mill, rod mill, pebble mill, electronic color sorter, electrostatic separator, and an air separator. Approximately 650 size analyses and 550 chemical analyses were performed during the investigation. Batch samples were tested by the Survey, and most of the continuous flow tests were handled by com-mercial laboratories. INTRODUCTION Although many companies producing gypsum have been interested in dry beneficiation, very little information has been published in the past. One of the most comprehensive investigations was reported by the Canadian Department of Mines.5 Other reports of interest have been published by the Canadian Department of Mines,&apos; the South Australian Department of Mines,2 and the U.S. Bureau of Mines.3 Some beneficiating practices, such as hand picking, selective mining, crushing and screening, milling, and air classifying, were already in use in the Canadian industry prior to MacPherson&apos;s investigations.5 MacPherson examined the effect of tabling, air separation, screening, flotation, electrostatic separation, calcining, washing, and various types of milling, in his efforts to eliminate dolomite, limestone, and small amounts of silica and clay from the gypsum ore. RAW MATERIAL Gypsum and anhydrite occur within the lower part of the St. Louis Limestone (Mississippian) in southwestern Indiana. Gypsum in single beds 10 or more ft thick occur at Shoals, Martin County; near Freedom, Owen County; near Bloomfield, Greene County; and in the Devonian strata of LaPorte County. Only the Shoals deposit has been exploited commercially. The western edge of the Shoals deposit is contaminated by a continuous bed of shale, about 1 1/2 to 2 ft thick, near the top of the evaporite and by thin continuous strata or irregular masses of carbonate rock. The low-grade material used in these investigations was obtained from the waste pile of the National Gypsum Co.&apos;s plant at Shoals. The waste ore averaged about 67.4% gypsum and was contaminated by various amounts of shale, dolomite, and limestone. All the material had been previously crushed and screened to minus 1 1/4 to plus 3/8 in. X-ray analyses of powdered, sedimentated, gly-colated, and heat-treated samples of the shale showed that it was composed of slightly structurally disordered illite, Fe-rich chlorite, and very finegrained disseminated silt. The clays and silt were partly cemented with carbonate material. Light-gray argillaceous limestone and gray or brown porous dolomite made up most of the carbonate rock contamination. Crushing Characteristics: The rate unweathered gypsum, carbonate rock, and shale reduce in size was determined by crushing handpicked samples in a rod mill and screening at minus 100 mesh (.0059 in.). Fig. 1 graphically represents the data. These data indicate that carbonate rock should be relatively easy to separate from gypsum, but that shale should be difficult to separate from gypsum by differential crushing. Controlled Samples: Eight rod mill tests of hand-picked samples of mixed gypsum and shale and mixed gypsum and carbonate rock were made. Sample weight and crushing weight were standardized, but the scalping screen size was varied from 3 to 10 mesh (.265 to .0787 in.) in order to obtain the optimum purity and recovery. The data obtained from the tests (see Table I) illustrate that the relatively hard carbonate rock allows appreciable beneficiation (13.6 to 18%), but the low strength gypsum and shale allows only minimal separation (3.1 to 7.5%).* Semi control led Samples: During the investigation considerable slaking of the shale was noted when the ore was subjected to alternate wetting and drying. As demonstrated in laboratory tests, as much as 76% shale can be removed by two cycles of wetting and drying in a 48-hour period with subsequent screening at .265 in. Five ore samples, stockpiled and weathered, were screened, rod-mill crushed and rescreened at .157 or .187 in. with excellent results (Table 11).

Jan 1, 1967

By J. D. Wood, J. T. Smith

ALLOYS with a dispersed second phase in a metallic matrix are generally much stronger than the matrix itself. Plastic deformation in dispersion-strengthened alloys is usually confined to the matrix phase when recovery processes are active, while in the absence of recovery both phases may yield.&apos; The alloy system studied in the present research was WC-12 wt pct Co and consisted of noncoherent WC particles dispersed in the cobalt matrix. Some particle-to-particle contact existed but not enough to produce a continuous WC skeleton. The microstruc-ture of the WC particles was characterized by very straight edges, forming a trapezoidal shape in any plane of polish. Previous investigations with WC-Co alloys at room temperature have shown that fracture of the WC particles occurs in transverse rupture testing.&apos; Room-temperature slip was reported for WC particles after indentation for hardness measurements.3 Elevated-temperature deformation of WC particles in a WC-12 pct Co alloy was suggested by recent electron microscope studies of specimens deformed at 900&apos; to 1000°C.4 In highly deformed alloys, the WC edges were serrated in contrast to the usual straight or smooth appearance. WC-12 pct Co and WC-15 pct Co alloys have been previously studied under elevated-temperature com-pressive-creep conditions by the present authors. Electron microscope studies of two-stage replicas from deformed specimens showed no evidence of slip or fracture of the WC particles. These specimens were brought to temperature and allowed to equilibrate prior to the application of the creep load. It was believed that the load-application rate, a crosshead speed of 0.005 in. per min on an Instron universal testing machine, was sufficiently low that recovery within the cobalt matrix was sufficient to limit the deformation to this matrix. A series of experiments was performed to evaluate the influence of loading rate on the deformation of WC-Co alloys. A WC-12 pct Co alloy was selected for these determinations. The average WC particle size was 4.45 p with an average linear separation between particles of 0.59 p. The selected temperature was 800°C and was monitored with a Chromel-Alumel thermocouple attached to the specimen. Testing was conducted in an argon-atmosphere chamber to prevent oxidation of the WC-Co specimens. This chamber was mounted on an Instron universal testing machine equipped to apply the load at a fixed rate. Each specimen was loaded to 110,000 psi compression stress at 0.05 and 0.5 in. per min. The loading rate was monitored prior to insertion of the test chamber and was found to be almost precisely the nominal rate selected. The specimens were raised to temperature and held to equilibrate with the surroundings, and then the load was applied and held for 4 hr to duplicate the exposure time utilized for the creep specimens. The time to reach full load at a crosshead speed of 0.005 in. per min was some 500 sec and was reduced to 50 and 5 sec as the loading rate was increased to 0.05 and 0.5 in, per min, respectively. The model developed by Ansell,&apos; when recovery processes do not occur, considers that fracture or deformation of the dispersed particles is necessary to relieve back stresses on dislocation sources and allow dislocations piled up against particles to sweep out in the matrix to cause plastic deformation; he further states that, even at elevated temperatures, the dispersed-particle deformation is necessary for yielding in the absence of recovery. For the case of straight dislocation segments piled up against a straight barrier, such as the straight-sided WC particles, the shear stress, 7 exerted on a particle is: where h is the spacing between particles (0.59 p), a is the applied stress (110,000 psi), p, is the shear modulus of the matrix (6.7 X lo6 psi at 80O°C), and b is the Burgers vector of the matrix dislocation. From Eq. [I], the shear stress, 7, exerted on the WC particles when no recovery occurs is of the order of 6 X lo6 psi at 800°C. The limiting stress, F, that will

Jan 1, 1969

By F. J. Mehringer, C. W. MacGregor

VARIOUS investigations have been carried out to determine the effects of cold-rolling on the common physical properties as represented by the yield strength, tensile strength, percentage of elongation and ordinary reduction of area. Very little information is available in the literature with reference to the effects of cold-rolling on the true stress-strain properties. Since the ordinary physical properties base both the stresses and the strains on the original dimensions of the test piece, which are greatly changed during the test, they are essentially empirical values and do not represent physically either true stresses or true strains. Consequently, they do not give an accurate picture of the effects of different conditions, both mechanical and metallurgical, on the strength and ductility of the material. It is not, however, the purpose of this paper to review the various advantages accruing from the use of true stress and true strain values, since these have been shown elsewhere,1-12 but to utilize them in representing the various effects considered. The true stress S and true strain (e = q&apos;) values mentioned above for the tension test are defined by1 [ ] where P, A, Ao are the axial load, the instantaneous area and the original area of cross section, respectively. From simultaneous readings of the axial load and the dimension or dimensions determining the instantaneous area of cross section, the true stress-strain curve is constructed by using the relations given in Eq. I. It is then the object of this paper to discuss the general effects of cold-rolling on the true stress and strain values for a low-carbon steel together with the effects of age-hardening and directionality on these properties. PRELIMINARY INVESTIGATIONS The material considered throughout the paper is a low-carbon steel of the following chemical analysis: C, 019 per cent; S, 0. 118; P, 0.092; Mn, 0.85; Si, 0.01. The stock was received in bars, 7 by 3/4 in., and was first annealed for one hour at 1650°F. followed by a furnace cool. Photomicrographs of this material showed considerable directionality even in the annealed condition. In view of the possible effects of the nonhomogeneity and directionality in this material, it was considered important to investigate their influence on the true stress-strain diagrams. In addition, the effect of strain-aging in this steel was also made the subject of a preliminary study. Elect of Aging on True Stress-strain Properties Since a certain time element would elapse between the cold-rolling operation and the final tension tests, it was determined to investigate the aging character-

Jan 1, 1945

By D. A. Woodford

A number of observations have now been reported where the steady-state creep rate is apparently linearly dependent on the applied stress at high temperature and low stresses. This results in a creep rate greater than that predicted by extrapolation of high-stress data and has obvious practical implications. However, some of these observations are open to question. For example, the analysis by Harris and Partridge17 of the data of Greenfield et a1.18 was dependent on strain rates which, according to the original authors, were too low to be measured. Dr. Bernstein appears to have demonstrated a linear stress dependence at low stresses in two zirconium alloys. There are, however, a number of discrepancies in his treatment of the data and the subsequent theoretical analysis which require clarification. 1) It is incorrectly stated that steady-state conditions are revealed by a slope of unity on a plot of log i vs log (time). This objection is trivial if the author meant to say a slope of zero, although it is unclear how subsequent extrapolation was made to determine the steady-state creep rates at low stresses for the zircaloy-2. If the plot used was actually log c vs log (time), it is unlikely that a slope of unity would represent a constant creep rate. A plot of log (c - co) vs log (time), where c0 is the extrapolated intercept sf the steady-state creep rate on the strain axis, would have a slope of unity during steady-state creep. However, eo cannot be determined unless is is already known. 2) The author chooses to interpret his results based on the equation: where A, and B, are structure-sensitive parameters, Ql and Q, are the activation energies for the particular creep process, and n describes the sensitivity of the creep rate on stress. The first term represents a slip creep process and the second a diffusion creep process. However, it is stated later that "two distinct processes acting in parallel are involved". Eq. [I] surely represents two processes in series since each reacts to the total applied stress and t, is the sum of the individual creep rates. If the processes are acting in parallel, then the effective stress in each would be less than the applied stress. The component stresses would be given by sl + s2 = a but it is not clear how the magnitude of either, or the corresponding stress exponent, could be determined.

Jan 1, 1969

GENERAL GEOLOGIC DESCRIPTION The mineral deposit of this case study can be described as a "typical" porphyry copper deposit of the southwestern USA and northern Mexico mineral province. The copper mineralization is related to Laramide age intrusives of intermediate composition which have been intruded into older, mostly crystalline, host rocks. Post Laramide deformation and faulting have subjected the deposit to erosion, leaching, and enrichment processes, which have created a secondarily enriched chalcocite zone. Later basin and range faulting down dropped the ore zone, resulting in deep burial beneath late Tertiary conglomerates and gravels, thus preserving the deposit from further erosion and oxidation. Lower grade chalcopyrite mineralization constitutes the primary zone underlying the enriched blanket. MANAGEMENT OF SAMPLE DATA Sample data were obtained from exploration diamond drill holes that were collared vertically and drilled with surface rigs. Most of the holes were surveyed downhole and found to deviate significantly from the vertical. The data were keypunched from original drill hole logs to formats as described in Chapter 6. Three types of cards were prepared: 1) A heading card containing the following information: [Project Name Coordi-in_ Hole Collarnates Bear-clina-Total ID Northing Easting Elevinglion Depth] 2) Individual record cards following each heading card with the following information: [SampleMin. Zone interval Assay Fields Leached (enriched ID From-ToTotal Cu Oxide Cu primary)] 3) Where downhole survey data were available, a card was punched for each downhole survey point. The card image looked very much like the heading card, followed immediately after the heading card, and contained the following information: [Hole Sur Point Sur Point Sur Point ID Bearing Inclination Depth] The keypunched data were then processed by the drill hole survey program producing a record file which contained information as follows: [Line 1. Project Name Date Assay Field Identifiers Line 2. Hole ID Northing Easting Elevation Bearing Inclination Number of Samples Line 3 through N+ 2 (where N equals the number of samples in the hole) Top Min. of Min. Zone Zone Sample Sample Coordinates Sample Assays Leach InterLength Northing Fasting Elev Total Cu Oxide Cu (etc) face] MINERAL BOUNDARY PROBLEM AND TREATMENT According to the geologic description, at least three mineral zones are present within the ore limits, as well as fault boundaries and a buried topographic surface, each of which have to be considered. The interfaces of the various mineralogical and geological boundaries were identified as accurately as possible in each drill hole by the project geologist, the location of the interface was surveyed in the computer program in association with the nearest sample intercept to the interface (note last field of line 3). Thus, the boundary is represented as a point in 3D space at each intersecting drill hole. The linear interpolation (LINTERP) program then searched the last field of the surveyed record to find the top of each mineral zone, or geologic boundary, and read the coordinates associated with that sample point. The program then used the coordinates to compute an interpolated surface between all existing data points as described in Chapter 11. A contour map was plotted for each of the computed surfaces and reviewed by the project geologist. Where the surfaces were poorly defined due to lack of real drill hole information, the geologist, at times, inserted a "pseudo" drill hole intercept according to his best judgment and feeling for the configuration of the surface, and such points were entered into the data stream for LINTERP. When the project geologists were satisfied that they had obtained

Jan 1, 1980

By GILBERT C. DAVIS

ANY thought of Morenci naturally includes its sister town of Clifton, its gateway to the outside world. Clifton, the country seat of Greenlee County, is the terminus of a branch line of the Southern Pacific railroad from Lordsburg, N.M. Carload freight incident to the Morenci operation moves from Clifton over Phelps Dodge?s standard-gauge industrial railroad. Private freight must be hauled by truck. These two communities fell far short of supplying adequate housing for the personnel concerned with the new operations so a new townsite, Stargo, was developed adjacent to Morenci. Here 234 housing units with garages have been built and twenty similar units have been erected near the reduction works.

Jan 1, 1942

By AIME

D R. GILLSON, who was born in Evanston, Ill., in 1895, is another one of those geologists who received his early inspiration and foundation in his science from that great teacher at Northwestern University, the late Professor U. S. Grant, and then went on to give his time and interest to Institute affairs-like those other Northwestern men, Arthur Blair, Gilbert Cady, Charlie Behre, Evan Just, Ian Campbell, Clayton Ball, and many others. After serving in the Navy in the first World War as, of all things for a geologist, a commissary officer on a transport, he went on to MIT and took his doctor&apos;s degree under Waldemar Lindgren in 1923. He even assisted in mineralogy at Harvard and thus had training under another great teacher, Charles Palache. He taught mineralogy and petrography at MIT from 1923 to 1928. After several summers of field work as an assistant in the U. S. Geological Survey, Dr. Gillson joined the staff of the du Pont company.

Jan 1, 1947

By Alexandre Mitinsky

The theory of elasticity, the science of the strength of materials, and all our calculations regarding engineering structures are based on Hooke&apos;s law, that in loaded bodies the deformations are proportional to the load producing them. Without this law it would be impossible to design intelligently engineering structures such as bridges, frames, axles, etc. This being the case, the proportional limit,l that is, the point at which deformation ceases to be proportional to load, is the most important factor in engineering design. Further, the working fiber stress should be fixed in reference to the proportional limit instead of, as is usual, in reference to the ultimate strength. The incorrect use of the ultimate strength instead of the proportional limit in setting the working fiber stress is probably due to two reasons: (1) it is a more delicate operation to measure the proportional limit; (2) it is usually assumed, though incorrectly, that the proportional limit is determined by the ultimate strength. In Germany the poin&apos;t at which permanent set first appears is often taken instead of the proportional limit. The two points will coincide if Gerstner&apos;s law, that elastic deformations are proportional to the loads producing them both before and after permanent set, is true; and the limit of proportionality and the elastic limit or point of permanent set will both be represented on a stress-strain diagram, by the point at which the line ceases to be a straight line and becomes curved or changes its inclination. It is to be further noted that the difference in definition between proportional limit and elastic limit introduces a difference in methods of determination in the testing laboratory. The German method of determining the elastic limit by alternately loading and unloading the test specimen is a lengthy process and time has in itself a very considerable influence on the results of physical tests.

Jan 1, 1916

By E. L. Jr. Spain

This study was undertaken primarily to determine the reasons for certain varia-tions in the soundness of gravel aggregate taken from a number of widely separated points on the Tennessee River. Under laboratory tests, concrete made with these various aggregates it some cases exhibited marked differences in specific gravity, crushing strength and durability. Gravel was studied in detail from Chattanooga to the mouth of the river and to a lesser extent from Chattanooga to Knoxville. The causes of variation were determined, and variational curves were constructed, which accurately predict the composition of aggregate at any point on the river and therefore its relative suitability for use in concrete. The aggregate at any point is suited for making sound concrete; the variance of suitability is due to varying percentages of sandstone and weathered material, which are less sound than other constituents. INTRODUCTION When it is stated that the aggregate from one point is inferior to that from another, it must not be construed to mean that the gravel is unfit for use. The classification upon which such aggregate ratings are based is largely arbitrary, thus inferiority or superiority is merely relative. Samples of gravel were selected from stockpiles at the dams of the Tennessee Valley Authority under construction, from the stockpiles of private companies along the river, and from samples taken by the gravel-exploration barge of the T. V. A. One hundred or more gravels of each size studied were selected at random by taking small handfulls while walking around the piles. These were separated according to the differ-ent mineral or rock constituents present, and the percentage of each constituent was obtained by counting. At least three such samples were taken from each size, and all checked with one another within a few per cent. The results were then averaged. In order to check on the accu-racy of such sampling, a whole sample was taken from one point after the gravel was thoroughly mixed. The two methods gave approximately identical results.

Jan 1, 1937

By F. Clerf

BLAST-FURNACE practice in France is determined more or less by the character of the ores used. Some French ores are siliceous and others are calcareous, therefore by proper burdening a self-fluxing mix can be used. This is not always clone, as, for instance, at the Caen furnaces of the Société Métallurgique de Normandie, where the Soumont ore of Normandy is used, which is a carbonate. This ore is crushed and calcined at the mines, yielding a product that is porous and well sized for blast-furnace consumption. The lines of the Caen furnaces are given in Fig. 1. Originally these furnaces had 16 tuyeres; six are plucked and these tuyeres are set in the lower part of the bosh. Operating data on these furnaces are given in Table 1.

Jan 1, 1937

By J. Chipman, N. J. Grant, H. L. Bishop, H. N. Lander

Data of several studies on the equilibrium between molten iron and open hearth-type slags have been combined to determine some of the chemical reactions involved in steel-making. Effects of slag composition and temperature on the iron oxide activity, distribution of sulfur between slag and metal, and the carbon content of the metal are discussed. Also, an overall reaction for the equilibrium between sulfur and oxygen is presented. DURING the past 15 years, a number of significant equilibrium studies have been carried out between liquid iron and simple basic and acid slags in an effort to throw light on the chemical reactions involved in steelmaking. This paper is a summary of the experimental reports on investigations which have been conducted at the Massachusetts Institute of Technology, and of related work in other laboratories. The investigations summarized in this paper include the works of Fetters and Chipman1 and Taylor and Chipman,&apos; which dealt with simple slags that are similar to those found in the open hearth. The sulfur determinations of the slag-metal tests of Fetters and Chipman as reported by Grant and Chip-man" are included. Also, the investigations by Win-kler and Chipman&apos; and Grant and ChipmanQ f more complex slag systems are included in this summary. The experimental procedure is described in detail in each of these papers and will not be discussed. Since the previous reports have been somewhat independent, it is desirable to review and combine the data of the various investigations to determine, as accurately as possible, the reactions in the slag-metal systems of the open hearth. It is the object of this report to present the combined data in such a way as to enhance their utility and applicability. Oxidizing Power of Slags of the System (CaO+MgO)-Si0,-FeO in Equilibrium with Carbon-Free lron The slags selected to determine the iron oxide activity in equilibrium with pure liquid iron were those containing less than 2 pct each of P,O,, MnO, or A1,0, on a weight percentage basis. The method used to calculate activities of iron oxide in liquid slags was that developed by Taylor and Chipman.&apos; The solubility of oxygen in molten carbon-free iron under pure iron oxide slags can be expressed by the following eauation —6320 log (pctO)-------------— + 2.734 [1] where T is the absolute temperature. The oxygen solubility values as determined from Eq. 1 were used throughout this study to calculate the iron oxide activity. The iron oxide activities of slags of various iron oxide contents are plotted in Fig. 1 as a function of the basicity, which is defined as the ratio (pct CaO + pct MgO)/pct SiO,, and are based on molecular percentage values of the components. The percent (FeO), is the total iron content in the slag calculated to FeO. Fig. 1 shows that as the basicity increases at constant mol pct (FeO),, the iron oxide activity increases rapidly and reaches a plateau which extends on the basicity scale from about 1.3 to 2.3; the iron oxide activity then decreases rapidly until a basicity of about 3.0 is reached, where it tends to level off. The solid portions of the curves represent the experimental data of Fetters and Chipman and Win-kler and Chipman. Their experimental heats were made in magnesia crucibles, and hence the slags were saturated with magnesia. The broken lines on the left represent the experimental data of Taylor and Chipman, who used a rotating crucible. In general, these slags contained less than 3 pct MgO. The absence of data for slags containing less than about 40 mol pct (FeO), and basicity ratios greater than about 2.5 made it necessary to calculate curves using ionic concepts of slags. The broken lines on the right, which disregard the solubility limits of di and tricalcium silicate and lime, were obtained by following the treatment of Flood and Grjotheim,"

Jan 1, 1957

By T&apos Ke, ing-sui

NUMEROUS investigators have observed that internal friction accompanies cold-working of metals and the effect of annealing is to reduce this internal friction.1,2 However, - most of the experiments were made at high stress amplitudes and the principal purpose was to study the increase of internal friction as a result of the applied cyclic stress during measurement. In order to study the internal friction introduced by cold-working applied prior to the measurement, the stress level applied during the measurement of internal friction must be sufficiently small. The results of measurement are significant and can be used for a base of comparison only when the applied cyclic stress is so small that the internal friction is independent of stress amplitude. Internal friction of cold-worked metals under small stress level has been studied by a number of workers8 -" he internal friction was measured around room temperature with a frequency of vibration of the order of kilocycles per second. The purpose of this paper is to report a study of the change of internal friction when severely cold-worked aluminum was annealed at successively higher temperatures until it was completely recrys-tallized. The measurements of internal friction were made over a range of temperature extending from room temperature up to the temperature of prior anneal. The frequency of vibrations used was about one cycle per second. The apparatus used for the internal friction measurements to be reported in this paper was a torsion pendulum with the specimen in wire form as the suspension fiber. The description of this apparatus and the method of measurement have been previously given.7,8 The applied stress was sufficiently small SO that the magnitude of internal friction is independent of stress level at each temperature range concerned. Corresponding to this stress the maximum shearing strain on the surface of the specimen is of the order of l0-5 and lower. The in- ternal friction (Q-1) is reported as 1/p times the logarithmic decrement. Internal Friction Versus Temperature of Anneal: Fig. 1 shows the internal friction measurements performed upon 99.991 pct aluminum subjected to 95 pct reduction in area. The final diameter of the wire is 0.033 in. This figure gives a general survey of the effect of temperature of anneal and of temperature of measurement. The internal friction of the cold-worked specimen was first measured at room temperature. It was then annealed at 50°C for one hour and the internal friction measured at 50°C and at room temperature. The same wire was successively annealed at higher temperatures for one hour and measurements were taken at the annealing temperatures and lower temperatures as before. Such a procedure was followed in order to stabilize the internal friction at the temperature of measurement so that during the measurement which generally takes about half a minute, there is no detectable change in internal friction. This series of measurements .was made up to 450°C. After each annealing a short test piece of the specimen, which had received the same past thermal and mechanical treatments, was taken out for metallographic examination. It is seen from fig. 1 that up to the annealing temperature of 250°C we have the following observations: for any given temperature of measurement, the internal friction is lower the higher the temperature of prior anneal. When the annealing temperature is 290°C or higher, the internal friction at the annealing temperature drops abruptly to a value which is much smaller than that for the previous curve. Metallographic examinations showed that the recrystallization of the specimen was completed after the annealing at 290°C. Fig. 1 shows that, as far as internal friction is concerned, there is no abrupt transition between the processes of recovery and recrystallization. Averbach has also reached the conclusion that recovery may be a process analogous to recrystallization on the basis of X ray extinction measurements in brass." The effect of annealing temperature upon the internal friction at room temperature is shown by curve I of fig. 2. In this figure the internal friction at room temperature was plotted as a function of annealing temperature. It is seen that the internal friction decreases rapidly at first with an increase

Jan 1, 1951