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By W. J. Babyak

The habit planes for hydride precipitation in large grains of alpha zirconium and Zircaloy-4 were determined in specimens containing 161 and 136 ppm hydrogen, respectively. In zirconium, the hydride platelets precipitated on various pyramidal planes inclined to the basal plane at angles ranging from 10 to 50 deg and 75 to 90 deg. Hydrides were most frequent at inclinations of about 20 deg and 90 deg. In Zircaloy-4, hydride plates were inclined to the basal plane at angles vanging from 5 to 25 deg with the predominant inclinatioiz equal to 12 deg; no platelets were found near the prism plane position. In both zircoinium and Zir-caloy-4, hydrides were principally, but not exclusively, parallel to (1011) type planes. When the Zircaloy-4 gmins were subjected to tension stresses of 12,100 psi and 19,400 psi during hydride precipitation, the hydride habit was unchanged except that precipitation favored those habit planes which were inore nearly perpendicular to the stress direction. The stress-orientatioiz effect increased with the magnitude of the stress. THE hydride habit plane in a zirconium has been determined by several investigators. Langeron and Lehr1 in 1956 found platelets parallel to (1010) slip planes. In 1962, Westlake and Fisher2 confirmed these findings and showed that hydride precipitation on twin planes, as reported by Kunz and Bibb,3 was probably due to incomplete removal of worked metal from specimen surfaces. Secondary habit planes, ( 1011) and (1015), were also found by Westlake and Fisher under particular charging conditions where a hydride layer may have existed at the hydrogenation temperature. Most recently, walters4 and westlake5 again observed the (1010) habit exclusively in zirconium. Louthan and hgermans have reported that hydrides precipitate on various ( 101l ) and (112l) planes positioned 31.5 to 90 deg to the basal plane in Zircaloy-2. The present investigation was concerned with the hydride habit in Zircaloy-4 in relation to that in zirconium and the possible change in habit when precipitation occurs under stress. The latter consideration was prompted by the stress-orientation phenomenon originally reported by Marshall and Louthan.7, 8 I) EXPERIMENTAL Materials and Specimens. Chemical analyses of all materials are given in Table I. The zirconium specimen was a 1 by 4 in. section cut from wrought crystal bar that was hot-rolled at 790°C to 0.300 in. and cold-rolled to a final thickness of 0.095 in. All surfaces were mechanically polished and then chemically polished with a solution of H2O, HNO3, and HF (10:10:l by volume) prior to annealing. Grains as long as 0.25 in. were grown by thermally cycling the specimen three times (in 10-5 mm Hg vacuum) between 825" and 1000°C at approximately 125°C per hr. The specimen was isothermally annealed at 825°C for 24, 40, and 120 hr after each cy-

Jan 1, 1968

By P. B. Knuckey, D. Littleford

The Kalengwa mine, situated in a remote area of Zambia in Central Africa, has presented some unique problems to the planners engaged in developing the deposit. This small, high grade copper deposit contains some 1,688,000 tons of ore at a grade of 9.3% contained copper. Of this 362,000 tons is classified as high grade ore at 27.2% Cu, the coarse fraction of which can be fed directly to converters; 733,000 is classed as intermediate grade ore averaging 6.3% Cu, and 593,000 tons classed as low grade ore containing 2.1% Cu. The geology of the deposit and the establishment of the mining operation is fully described. A concentrator is being built at Kalengwa to treat the high grade fine product, intermediate, and low grade ore, whilst the coarse high grade ore will be trucked to the Copperbelt smelters for direct smelting. Details of metallurgical processing are given. The decision to truck the coarse high grade ore to the smelters on the Copperbelt necessitated the construction of a new 200-mile road, the setting up of a fleet of heavy ore transport trucks and associated equipment. The remoteness of the area from established communication facilities on the Copperbelt necessitated the provision of radio communications between Kalengwa and the head office at Kalulushi, and the establishment of a regular mine air service. The paper also describes the training of an unsophisticated local population in the operation of heavy plant and machinery, the establishment of the township, and the provision of health services.

Jan 1, 1972

By K. J. McGrew, J. W. Murphy

Introduction Maximization of profit consistent with environmental protection is the principal goal of new applications development for any conventional or in situ mining technique. Efficient evaluation of all the parameters that contribute to mining costs and production hinges on proper design and evaluation of testing programs and data. The program discussed uses several field and laboratory procedures to estimate ore deposit characteristics and optimize lixiviant compositions. Ore characteristics and lixiviant compositions are then used in a long path leaching test (stream tube test). Stream tube test data are analyzed by mathematical models with computer assistance to predict such wellfield rate parameters as target metal production, lixiviant consumption, and restoration. When these predicted rates are combined with market values for target metals, capital expenditures, prices of lixiviant chemicals, and other economic variables (labor costs, power rates, and licensing fees), an assessment of the relative feasibility of various proposed mining plans is possible. The flowsheet in Fig. 1 illustrates this process. [ ] Field and Laboratory Procedures In general terms, the procedures followed in the evaluation of an in situ leaching application aim at accomplishing: •rapid leaching and maximum recovery of the target metal in a marketable form, •low consumption of lixiviant chemicals, •unquestionably satisfactory restoration of the mined aquifer, and •minimization of capital and operating costs for the above through development of an optimum mine plan. Keeping these goals in mind, the following minimum test program is generally recommended. Geology •Estimate of ore reserves and their variability. •Average disequilibrium value for uranium deposits. •Ore thickness, depth to ore, water level, degree of confinement, and consolidation. •Characterization of quality and quantity of other ore deposit constituents (e.g. sulfide minerals, ion exchange parameters). Hydrology •Single well pump and injectivity test. •Downhole vertical permeability test to compare flow rates of barren and mineralized formations. •Groundwater quality as it may affect licensing, hydro metallurgy, and restoration. Hydrometallurgy • Flask or autoclave tests for optimization of lixiviant parameters and determination of specific reaction rate constants. • Flask or autoclave tests for assessing amenability of lixiviant solutions with ore, consumption of lixiviant, stability of metal in solution contacting ore, and environmentally important species mobilized. • A long-path leach test for modeling the behavior of the lixiviant solution flowing through a long mineralized streamline (stream tube testing). •Metal recovery tests from lixiviant solutions (ion exchange, electrowinning, etc.). •Lixiviant regeneration tests. •Environmental restoration tests.

Jan 1, 1985

By E. A. Nesbitt

The important permanent-magnet alloys 15 years ago contained carbon and depended upon it for their permanent-magnet properties. In recent years great advances have been made in a number of new alloys substantially free of carbon. These include Remalloy,' an alloy of iron, cobalt, and molybdenum, the various iron-nickel-aluminum alloys of the Mishima2 type, and the more recent Alnico V3 in which the best properties are developed by heat-treating in a magnetic field. The Mishima and the Alnico types of alloys are very brittle and after casting must be ground to size. This article describes a permanent-magnet material4 that can be machined as cast, and when handled with some care can be rolled to thin sheet and drawn to fine wire. Optimum magnetic properties are developed by a simple heat-treatment, and at this time the ductility of the alloy disappears. If the cast alloy is heat-treated without cold-working the mag netic energy product is about 1.0 X 106. This material is called Vicalloy I (pronounced vicalloy, V for vanadium, I for iron, and C for cobalt). When the alloy is first hot-worked and then considerably reduced in area by cold-swaging, drawing or grooved rolling, it is found that after heat-treatment the magnetic energy product measured in the direction of previous extension can be increased to 2.0 to 3.5 X 106. These higher values have been obtained only after reductions in area of 75 to 95 per cent, and since the material hardens considerably during working, the reduction ordinarily can be accomplished only in fine wires, although larger sizes can be reduced by the use of powerful machinery. When the material has been cold-worked in such a manner as to improve its energy product substantially, it is called Vicalloy 11. Commercial use of Vicalloy has been made in the recording of speech. Tape 0.002 by 0.050 in. has been found superior in quality to all others tried, and is now used in the Western Electric Mirrorphone 5 In a variety of forms Vicalloy I or I1 is useful in many laboratory instruments, and in experiments in which the sizes and shapes required cannot be obtained with the other more brittle permanent-magnet materials. In 1936, during a study of other age-hardening magnetic systems, it occurred to the author that some of the iron-cobalt-vanadium alloys might be suitable for permanent magnets. The proportions of iron, cobalt, and vanadium were varied and a range of alloys of particular interest was found, as shown by the indicated area in Fig. I. The limits of this range of composition are 30 to 52 per cent iron, 36 to 62 per cent cobalt, and 4 to 16 per cent vanadium. The compositions indicated by points outside this area were also tested. Preparation and Properties OF Vicalloy I The alloys were usually cast in graphite molds into bars 3/4 in. in diameter and

Jan 1, 1946

By E. A. Nesbitt

The important permanent-magnet alloys 15 years ago contained carbon and depended upon it for their permanent-magnet properties. In recent years great advances have been made in a number of new alloys substantially free of carbon. These include Remalloy,' an alloy of iron, cobalt, and molybdenum, the various iron-nickel-aluminum alloys of the Mishima2 type, and the more recent Alnico V3 in which the best properties are developed by heat-treating in a magnetic field. The Mishima and the Alnico types of alloys are very brittle and after casting must be ground to size. This article describes a permanent-magnet material4 that can be machined as cast, and when handled with some care can be rolled to thin sheet and drawn to fine wire. Optimum magnetic properties are developed by a simple heat-treatment, and at this time the ductility of the alloy disappears. If the cast alloy is heat-treated without cold-working the mag netic energy product is about 1.0 X 106. This material is called Vicalloy I (pronounced vicalloy, V for vanadium, I for iron, and C for cobalt). When the alloy is first hot-worked and then considerably reduced in area by cold-swaging, drawing or grooved rolling, it is found that after heat-treatment the magnetic energy product measured in the direction of previous extension can be increased to 2.0 to 3.5 X 106. These higher values have been obtained only after reductions in area of 75 to 95 per cent, and since the material hardens considerably during working, the reduction ordinarily can be accomplished only in fine wires, although larger sizes can be reduced by the use of powerful machinery. When the material has been cold-worked in such a manner as to improve its energy product substantially, it is called Vicalloy 11. Commercial use of Vicalloy has been made in the recording of speech. Tape 0.002 by 0.050 in. has been found superior in quality to all others tried, and is now used in the Western Electric Mirrorphone 5 In a variety of forms Vicalloy I or I1 is useful in many laboratory instruments, and in experiments in which the sizes and shapes required cannot be obtained with the other more brittle permanent-magnet materials. In 1936, during a study of other age-hardening magnetic systems, it occurred to the author that some of the iron-cobalt-vanadium alloys might be suitable for permanent magnets. The proportions of iron, cobalt, and vanadium were varied and a range of alloys of particular interest was found, as shown by the indicated area in Fig. I. The limits of this range of composition are 30 to 52 per cent iron, 36 to 62 per cent cobalt, and 4 to 16 per cent vanadium. The compositions indicated by points outside this area were also tested. Preparation and Properties OF Vicalloy I The alloys were usually cast in graphite molds into bars 3/4 in. in diameter and

Jan 1, 1946

By Richard Hamburger

The purpose of this paper is to call attention to certain methods which will shorten and simplify the calculation of plane tri-angulation. These methods, though not new & do not appear to have been properly publicized in the United States. The cotangent (or tangent) solution of a triangle permits calculation of coordinates in a smooth series of operations of the calculating machine with a minimum of notation. The semigraphical solution permits the simultaneous solution of a number of intersections, at one station, without the added burden of solving additional triangles. This in turn encourages more numerous field checks and more complete office computation than would normally be undertaken. RICHARD HAMBURGER, Junior Member AIME, is Junior Engineer, Inspiration Consolidated Copper Co., Inspiration, Arizona. TP 2798 A. Discussion (2 copies) may be sent to Transactions AIME before March 31, 1950. Tables I and I1 show the distinct advantage which the combined use of the cotangent and the semi-graphical solutions hold over, what might well be called, the standard solution. It will be shown that the positions for the entire net in fig. 1 may be calculated without computing any distances, thus saving much computation. (2) Comparison of Cotangent and Standard Solutions: To compare the cotangent method with the standard method, the notation involved in the solution of triangle 1-X-4, fig. 1, by both methods is shown. Fig. 2 shows the given information, that is, the coordinates and azimuths of Stations 1 and 4, and angles of the triangle or the azimuths from Stations 1 and 4 to Station X. (Azimuths are used here because the author feels that they are easier to handle, but bearings may be used by those who prefer them). It will be seen from the above comparison that the advantages of the cotangent solution of a triangle are: (a) rapidity, (b) full use of the calculating machine, (c) the small number of

Jan 1, 1951

By Myers, J. F.

The purpose of the mill tests reported herein, was to determine the relative power efficiency of fast and slow rod mill speeds on the ores of the Tennessee Copper Co. The tests were carried out at the lsabella Mill of the Tennessee Copper Co. under normal operating conditions. Every effort was made to keep the ore supply and other conditions constant, but it will be noted that some slight variation did occur. The open circuit 6 by 9 rod mill, and ore, used in these tests have been previously described.' Four motor drive pinions were available and the tests were performed in the following manner: each pinion was used to drive the mill for a period of one week. Constant sampling prevailed during the test run, and a composite sample for each speed test was made. Realizing that some slight liner wear took place during the four-week test-run, and that some slight variation of the ore may have taken place, a second and then a third series of four-week test- runs were made with the four different pinions. The screen analysis of each of the thee-week run samples at the various speeds were composited and the results are shown in Table 1. The authors feel that the 12 weeks of operation consumed during these test-runs would represent fairly the effect of each mill speed. The data of line 37 show that within the error of sampling and plant operation, the tons of minus 65-mesh material generated per horsepower hour was the same at all four speeds.

Jan 1, 1949

By Richard Hamburger

(1) Introduction: The purpose of this paper is to call attention to certain methods which will shorten and simplify the calculation of plane tri-angulation. These methods, though not new,',2 do not appear to have been properly publicized in the United States. The cotangent (or tangent) solution of a triangle permits calculation of coordinates in a smooth series of operations of the calculating machine with a minimum of notation. The semigraphical solution permits the simultaneous solution of a number of intersections, at one station, without the added burden of solving additional triangles. This in turn encourages more numerous field checks and more complete office computation than would normally be undertaken. RICHARD HAMBURGER, Junior Member AIME, is Junior Engineer, Inspiration Consolidated Copper Co., Inspiration, Arizona. TP 2798 A. Discussion (2 copies) may be sent to Transactions AIME before March 31, 1950. Tables I and I1 show the distinct advantage which the combined use of the cotangent and the semi-graphical solutions hold over, what might well be called, the standard solution. It will be shown that the positions for the entire net in fig. 1 may be calculated without computing any distances, thus saving much computation. (2) Comparison of Cotangent and Standard Solutions: To compare the cotangent method with the standard method, the notation involved in the solution of triangle 1-X-4, fig. 1, by both methods is shown. Fig. 2 shows the given information, that is, the coordinates and azimuths of Stations 1 and 4, and angles of the triangle or the azimuths from Stations 1 and 4 to Station X. (Azimuths are used here because the author feels that they are easier to handle, but bearings may be used by those who prefer them). It will be seen from the above comparison that the advantages of the cotangent solution of a triangle are: (a) rapidity, (b) full use of the calculating machine, (c) the small number of

Jan 1, 1951

By Sherwin Kelly

IN presenting this brief historical perspective, it is not my purpose to address myself to the geophysicists, to most of whom the story is already well known. My objective is to draw the attention of those who hold the belief that geophysics is something new, typically twentieth century, to the fact that fundamentally, whether it was known by the name of geo-physics or not, the science is an ancient and an honorable one. It began many centuries ago, and our modern civilization and its commerce owe a great debt to its founders, who today are likely to he overlooked and their names forgotten. The word "geophysics" means the physics of the earth, and is descriptive of a science that in many ways bears the same relationship to geology that astrophysics does to astronomy. When dealing with dis-tant stars or deeply buried rocks, the experimenter cannot reach them to obtain samples, which can be taken to his laboratory for study. He therefore exhibits the resourcefulness of Mahomet in the mountain episode, and makes the terrestrial globe or the cosmic universe his labora-tory, studying the effects of distant bodies on certain "fields of force"" which come to him across interstellar space, or through the rocks that make our earth. The application of these techniques of the physics laboratory to the study of the stars is the science of astrophysics, and to the investigation of the earth is geophysics. Yet the origin of the most valuable contribution to the world's trade and commerce ever made by geophysics remains lost in deep obscurity. Unknown even is the country wherein lived the unsung genius who invented the first geophysical instrument, the mariner's compass! Worse yet, it is not certain whether this invaluable guide of man had its begin-nings in Europe or in Asia. A Chinese legend tells of the Emperor Hwang-ti, who attacked his enemy Tchi-yeou on the plains of Tchou-lou in the year 2634 B.C., whereupon the latter magically raised such a fog that the Emperor could not pursue the retreating troops. Not to be outdone, the mighty ruler constructed a chariot that indicated the cardi-

Jan 1, 1938

By Raja V. Ramani, Ralph W. Barbaro

This paper presents an application of a Mixed Integer Programming (MIP) model to the problem of locating a centralized coal preparation plant and determining the production schedule for the mines. The system used for illustrating model application is hypothetical but realistic. It consists of three mines, two potential preparation plant sites, heavy media processing plant, and one market. The goal is to maximize the total profit of the system while satisfying the coal delivery schedule over a three year period meeting both quantity and quality requirements (ash, sulfur, and heat content). In addition to the base case, four different scenarios are analyzed. These four modifications are: (1) removing the flotation circuit from the preparation plant and sending all of the fines directly to the clean coal, (2) lowering the quality of coal from one of the mines, (3) applying discounts to the unselected site to improve its competitive position, and (4) adding a new mine. A detailed discussion of the base case and the effect of these four alternatives is presented.

Jan 1, 1983

Henry Louis, Newcastle-upon-Tyne, England (communication to the Secretary): I think very highly of the novel and ingenious device of Prof. Richards for analyzing the movement of the various elements of the jig; it is a method that certainly seems to promise valuable results, if we could only make certain that these various indicator-appliances have no effect upon the action of the jig. I would like, however, to suggest that in future experiments the connection between the plunger indicator-rod and the pencil should be made by means of parallel motions, so as better to reproduce the rectilinear motion of the piston. I should expect, if this were done, that the " curve " of the plunger in the Harz jig, at any rate, would be represented either by straight lines or else by quite regular curves, according to the method by which the plunger is set in motion; the apparent combinatioil of straight line and curve seems difficult to explain. With respect to the water-curve, I am afraid I am completely at fault, but no doubt Prof. Richards can explain my difficulty. In Fig. 2, the areas of the screen-side and the plunger-side of the jig are equal. If the piston be a fair fit and the bottom of

Jan 1, 1897

By Henry G. Granger

A residence of 14 Sears in the Republic of Colombia, spent . in almost continuous traveling and prospecting-trips, has given me an intimate knowledge of the resources of that wonderful country. The man who best knows Colombia is unquestionably General Rafael Reyes, President of the Republic for the past three years, and with seven years more to serve in his present term. Such is the strength of his personality and the wisdom of his policies that his term of office will no doubt endure as long as he is milling to serve. The vastly improved economic situation and the brilliant outlook for Colombia are so directly due to the influence of President Reyes that a few lines concerning him will not be amiss, if they serve towards a better understanding of his personality. Born of a distinguished ancestry in the mountain~ of Boyaca, he is now 57 years old, just the age of his friend Porfirio Diaz when he began the work which has placed Mexico in the rank of great modern nations. It was Reyes who came to Washington to protest against the action of the government of the United States of America in

Jan 1, 1909

By David J. Dunn

GENERAL NOTES Liner Design for Comminution Liners in crushers and mills are the mechanical link between machine and ore. The way liners transfer energy to media and ore determines to large degree the production rate, liner wear rate, maintenance cost, energy use, and availability of the comminution process. Plant capacity and mineral recovery economics, and return on investment, are thus strongly dependent upon these simple, low cost metal shapes of which so much is demanded. The complexity of dynamic relationships between liner configuration, material properties, ore characteristics, and operating parameters defy simplistic generalization. Rules-of-thumb and axioms of years past fall into disuse almost daily as new analytical methods, assisted by computers and sophisticated control systems, are applied to crushing and grinding processes. Recent literature is well supplied with references citing production benefits that improved liner designs produce. This chapter is intended to review especially promising liner designs and material developments and presents cameo case studies showing the benefits derived from their application to comminution circuits (Tables 1,2,4,5,7). Complete discussions of liner design and wear materials are beyond the scope of this chapter. Norman's comprehensive studies in references (1) and (2) and Mclvor's analyses of mill speed/configuration effects (3) are especially useful reading for designers and operators of crushing and grinding circuits. Changing trends in ore, product value, and costs of wear materials, interest, labor, and energy, make ongoing evolution of liner design equally important for existing mines and for projects still on the drafter's board. Original designs supplied as new equipment must, of necessity, be best estimates. These can usually be improved as operating experience replaces engineering forecasts. Advent of new materials or design concepts such as the Angular Spiral Liners (Korpi (4) ) or Norman's Bimetallic design (2) offer improvement potential that must be evaluated if a given circuit is to be kept competitive versus others making similar products.

Jan 1, 1982

By V. V. J. Sarma

Interpretation of earth resistivity data involves not only obtaining depth to interfaces but also determining the nature of formations from their resistivity characteristics. Moore's method of interpretation envisages obtaining depths to the interfaces alone. A simple method of estimating the true resistivity values of formations by applying Hummel's formula of average resistivities is proposed. The method would increase the interpretative value of Moore's method as originally proposed. For most of the earth resistivity measurements, the four-electrode configuration developed by Wennerl is employed. In principal, the method consists of energizing (Current I) the ground through two outer electrodes and measuring the resultant potential (v) between the two inner electrodes. The configuration is such that the separation (a) between any two successive electrodes is equal. The apparent resistivity (pa) for such a configuration is given by 2p- a (V/I). By increasing the electrode separation (pa vs a) curves are obtained. Ideally, a homogeneous isotropic formation underground has a characteristic resistivity. However, the field conditions do not present such ideal cases. Almost invariably, even in the same geological bed, the physical conditions are widely different at different parts in the bed. It is further shown that the penetration of the current into the ground for a given horizontal electrode separation, a, is roughly down to a depth, equal to a. It is therefore, evident that the apparent resistivity calculated from the field observations is a weighted average of the resistivities of the materials present down to this depth. With some prior knowledge about the relative dispositions of the geological formations and their physical conditions, it would be possible, by resistivity surveys, to obtain characteristic resistivities for these formations. It is, thus, that the apparent resistivity-electrode separation curves enable one to decipher the resis- tivity distribution at various depth levels and therefore the nature of the geological formations present. Both empirical and theoretical methods have been developed for determining resistivity characteristics of the various formations. The theoretical methods proposed by Tagg2 and Roman3 are derived from studies of the potential distribution on the surface due to the presence of layers of widely differing resistivities underground. The more recent methods of Wetzel and McMurry4 and Wetzel and Mooney5 are but extensions of the original Roman method of superposition. These methods suffer from lack of similarity of the actual field conditions with those of assumed conditions in developing the theory. The empirical methods such as the one developed by Gish and rooneY6 depend purely on personal observation and local peculiarities, and are applicable only for those limited areas. Out of the empirical methods, moore's7 cumulative resistivity method is still found to be applicable in several localities of differing conditions. While Reudy in 1945 adduced some theoretical justification for the method (Eve and Keys),8 Muskat9 and Mooney 10 tried to show the lack of theoretical basis for the same. It is, however, observed that the method in practice "forms a valuable means of successfully attacking the apparent resistivity curves which fail to respond to the Gish-Rooney, the Tagg or the Roman logarithmic methods" (Ramachandra Rao). 11 Comparatively good results are also reported by Melbyel2 by employing Moore's method in interpreting the resistivity results obtained for ground water in the city of Gunnison, Colo. MOORE'S METHOD As has already been pointed out, the application of the theoretical methods is time-consuming, laborious and sometimes not applicable for quick and accurate interpretation of the field data. moore7 has developed a quick method for obtaining depths to interfaces by plotting the cumulative sums of resistivities, against the corresponding electrode separations a instead of plotting the usual Pa — a curve. In this process of continuous integration, corrections for small variations in resistivities, arising due to local surface conditions or adjacent layers, are made, while large consistent variations are brought out

Jan 1, 1963

By M. G. Jones

AT the Edwards mine a 4 by 81/2-ft two-compartment shaft is used for men and supplies in the older workings down to the 900-ft level. All ore is hoisted through a 5 by 15-ft three-compartment vertical shaft which extends to the 1500-ft level. Ore pockets are on the 1300- and 1500-ft levels. The two-compartment countershaft used below the latter level is 6 by 12 ft inclined at 42°. Ore from the countershaft is hoisted to the 1350-ft level where it flows by gravity to the 1500-ft level ore pocket. One-ton skips are used in balance in the countershaft and two-ton skips, also in balance, from the 1500-It level to the surface. These skips are slung under the man cages. Each level has an ore pocket of 200 tons' capacity. Development at Edwards is similar to that at Balmat except that haulage drifts are only 7 by 7 ft. They are mucked with Eimco-Finlay No. 12 loaders. A drill carriage similar to that used at Balmat is being tried out on the new 2300-ft level, the present bottom of the mine. Drifts are driven below grade and later raised 6 in. and ballasted with waste leaving a ditch 6 by 12 in. at one side for drainage. All development is done on an incentive bonus system, the miner paying for his explosives.

Jan 1, 1947

By M. A. Childers

Recent work with controlled laboratory tests.' field experience and a new analytical approach indicate that casing centralization, pipe movement and relative rheological properties between the mud and cement (yield point and density) are the three controlling factors in successfu1 primary cementing of dual casing. Turbulent flow has been demonstrated to be unnecessary under the severe displace ment conditions of parallel dual strings of casing. Simultaneous reciprocation of dual casing in directionally drilled boreholes is highly dependent on centralization and on the rapid initiation of pipe movement once the casing has been run to total depth. Successful cementing of 30 out of 32 dual, 3%-in casing wells substantiated these conclusions. A review of 15 dual, 3 1/2-in. casing wells completed prior to the adoption of these principles disclosed only one success. Mathematical and graphical techniques permit the engineer to analyze and anticipate the success or failure of a cementing operation. Standoff, mud displacement and reciprocation can be analyzed mathematically and planned in deep, directional or straight boreholes by review of annular geometry, relative rheological properties between the mud and cement, and forces caused by caring weight, functional drag and differential sticking. Introduction The objective in primary cementing is to displace the drilling fluid with cement that will bond to the formation and casing to prevent communication through the annulus. The predominant cause of failure appears to be channels of gelled mud that remain in the annulus after cementing.1 '* Past investigations have noted many procedures that could improve the displacement process.2-' These procedures include centralization, chemical preflushes, mechanical mud cake removers, controlled flow rates in certain regimes, pipe movement an1 control of mud and cement properties. Not until recently have the effects of many of these procedures been isolated so that their individual importance could be determined. In a recent paper,' a comprehensive and analytical laboratory study of various factors controlling the displacement process concluded that there are three major factors in obtaining complete mud displacement by the cement slurry. 1. Good relative rheological properties between the mud and cement. The cement should be heavier and have a yield point and plastic viscosity higher than the mud being displaced. Buoyancy forces often can dominate the displacement process. 2. High degree of standoff or centralization. The more centered the casing, the greater the likelihood of complete mud displacement and removal. 3. Pipe movement obtained by rotation or reciprocation. Often unfavorable rheological properties between the mud and cement, and poor standoff can be compensated by pipe movement. This work demonstrates the compatibility of the latter concepts with field results extended to the more severe dual casing displacement process. Early Experience With Dual 3'/t-In. Primary Cementing Early slim casing completions in the West Delta Block 73 field, offshore Louisiana, included 17 dual 3%-in., 3 single 3% -in. and 1 dual 2% -in. casing installations. Table I provides data on these earlier wells. Usually, common Class A cement was placed across the pay zone and 12 percent gel cement was placed to a height of 500 ft above the highest productive sand. Centralizers (6%-in. OD maximum expansion) were placed two or three per joint on both casing strings from total depth through the completion intervals and at least one per joint for the remainder of the cement sheath. A number of techniques and procedures were attempted to improve cementing success. Casing was run simultaneously or separately with a number of mud conditioning and circulating techniques. Mechanical aids such as cement bonders, slmiding sleeves, turbulizers and various sizes and strengths of centralizers were used. Common and gel cements were mixed with fresh or sea water with a number of different additives to control retardation and dispersion. Cements were thinned and mixed at high rates to try to induce turbulent flow in the annulus. On one well the "slow flow" method was used." Perforating was accomplished with a jet orienting gun. Unsuccessful cement jobs were indicated by production of extraneous fluids or by pressure communication between zones. On test, five wells flowed water, four flowed sand and six had pressure communication with the other string or the 10%-in. casing. A total of 25 remedial squeeze ce-

Jan 1, 1969

By EL HANAF

The exploratory program initiated in Egypt in 1937 by four major oil companies was well under way early in 1939. Extensive gravity-meter surveys were carried out in the Sinai Peninsula and the Eastern and Western Deserts. Seismic and magnetometer work vas conducted on a restricted scale. The data collected justified wildcat drilling on structures located geophysically and/or geologically.

Jan 1, 1946

THE CHAIRMAN (H. W. MORSE, Los Angeles, Cal.).-I would like to open this meeting for a little while to the general subject of leaching. We ought not to hold back if we have any new schemes for the future. I know that those of us who are tangled up with this lei thing work will appreciate any suggestions that will make us work harder and, scheme, harder to pull through these past difficulties on leaching. F. S. SCHIMERKA, Clifton, Ariz.-Under the direction of J. W. Bennie, General Manager of the Shannon Copper Co., Clifton, Ariz., 'it has been my valued privilege to cooperate in the elaboration of a hydrometallurgical process aiming at the recovery of copper in mill tailing resulting from a gravity concentration of a low-grade semi-oxidized sulphide ore occurring in a porphyritic gangue. The experimental work which has been carried on with a 25-ton plant is completed, and the company is building at present a leaching plant on a larger scale, the first unit consisting of a 150-ton roasting furnace and accessories for leaching the calcine.

Jan 12, 1916

By W. F. Carew, F. A. Crossley

Tensile, creep-rupture, and stability tests were employed to evaluate the effect of a-strengthening and ß-complexing additions on the base composition Ti-6Al-3Mo. The ultimate objective was to produce an alloy of greater strength than the Ti-7A1-3Mo alloy. Strengthening of a was accomplished by additions of 2 and 4 pct Ge, 4 pct Sn, 4 pct Zr, and 2 pct Sn-2 pct Zr. Making the ß more complex while keeping the total of ß-stabilizing additions constant at 3 pct resulted in higher tensile strengths but lower creep and rwpture strengths, especially at 1000°F. None of the more complex versions of the base alloy offers greater promise than the Ti-7A1-3Mo alloy. However, some improvement in the strength of the latter may follow from additions of zirconium perhaps up to 4 pct. PREVIOUS work directed at the development of titanium-base alloys with: 1) minimum room-temperature tensile elongation of 10 pct in 1 in., 2) high creep resistance at elevated temperature, and 3) the ability to retain original room temperature tensile ductility following exposure to creep conditions at elevated temperatures, demonstrated Ti-Al-Mo ternary compositions in the range 5 to 7 pct Al-3 to 6 pct Mo to be the most promising. Of this group the Ti-7Al-3Mo alloy was the strongest.'-= The objective of the present work was to determine if alloys of this type could be further strengthened by making additions which dissolve preferentially in the a-phase and by making the ß-phase more complex. For this study the base composition Ti-6Al-3Mo was selected rather than Ti-7Al-3Mo in order to minimize the possibility that in a more complex alloy with a-strengthening additions, low ductility might obscure the strength contribution. The metals

Jan 1, 1959

By S. F. Emmons

[The following notes of observations made during a visit of a few days in the month of October, 1886, which was cut short by a sudden summons East, are offered, in spite of their incomplete and tentative character, in the hope that they may aid the members of the Institute, in their coming visit to this region, to a clearer understanding of the general geological conditions under which the ore-bodies occur.] The Butte mining region lies in a sort of a depression in the mountains which is drained by Silver Bow creek and its various tributaries. On the east it is bounded by high north and south ridges of granite, and on the west by lower ridges, also running north and south, which, as far as examined, were found to consist of rhyolite. High mountains also inclose the depression on the north and south, but at a greater distance than the more immediate bounding ridges on the east and west, the distance between which is hardly more than six miles.

Jan 1, 1888