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By AIME AIME

THE portrait of Herbert Hoover, President of the United States, recently painted by Philip A. de Laszlo at the request of the four Founder engineering societies, was unveiled at a special meeting in the Engineering Societies Building on Feb. 15. The portrait was delivered by Gano Dunn, chairman of the Hoover Medal Board of Award, who said, in part:,

Jan 1, 1932

By Francis Lucas

EACH year we gather in this auditorium to honor the memory of a . distinguished American metallurgist and educator. I cannot bring to you reminiscences of Prof. Henry Marion Howe as other lecturers have done. It was not my good fortune to enjoy the privilege of studying and ,working under his direction. As I have reflected on the published works of Professor Howe, it has seemed to me that his mind was trained on the nature of metals and on the mechanism which produced known but unexplained effects. He was interested in controlling and regulating the causes so as to produce specific effects, useful in serving mankind. I recall an afternoon in May, 1925, when, at the invitation of Mrs. Howe, I visited his former home, Green Peace at Bedford Hills, N. Y. The purpose of my visit was to receive at the hands of the widow -an engraving of Professor Howe, a reproduction of a painting from life. Mrs. Howe showed me his study. The walls of this large attractive room, brilliantly illuminated by the spring sunshine, were literally covered with the scrolls of honors and of decorations which had been conferred on Professor Howe by governments, academies, universities, societies and. institutions the world over. As we walked about the room, she pointed out the significance of each honor and recited a few details of each occasion. I sensed the pride with which Mrs. Howe, then in the late autumn of her life, told me of her husbands' achievements, of his struggles, of his disappointments and of his successes. There was a surprisingly familiar note in the recital to which I was listening. I have found the same theme running as a disconnected thread through the written accounts of the lives of most men of science. We then went to the drawing room to chat for a few minutes before I said my farewells. As we seated ourselves, Mrs. Howe turned to me and asked: "Mr. Lucas, what of this great microscope of yours? Cannot it be applied to the study of disease? What a great blessing it would be if it could be directed to relieve the suffering of mankind."

Jan 1, 1931

By J. E. Johnson

At the Cleveland meeting of the Institute in October, 1912, I had the honor to present a paper outlining the conditions surrounding the charcoal iron industry…

Jan 1, 1915

THOSE MARKED THUS * ARE MEMBERS, MARKED THUS ?ARE ASSOCIATES. THESE SIGNS DOUBLED INDICATE LIFE MEMBERS AND ASSOCIATES RESPECTIVELY. THE FIGURES AT THE END OF THE ADDRESS INDICATE THE YEAR OF ELECTION. HEAVY-FACED TYPE SIGNIFIES HONORARY MEMBERSHIP. *AARONS, J. BOYD, Vivian Gold Mining Co., Ltd., Harris, West. Australia. '05 *ABADIE, EMILE R., Cons. and Min. Engr., 214 Union Savings Bank Bldg., Oakland, Cal. '76 ?ABBÉ, MAX F., Prest., Abbé Engineering Co, 220 Broadway, New York, N.Y. '07 ? ABBÉ, PAULO., Secy.,Abbé Engineering Co., 220 Broadway, New York, N.Y. '07 *ABBOTT, AI ARTHUR Morococlia, Peru, So. America. '95 *ABBOTT, CLARENCE Chief EDgr., Iron Mines, Dic Tennessee Caol, Iron & R. R. Co., Bessemer, Ala. '04 *ABBOTT, JAMES W., Min. Engr: Ploche, Lincoln Co., Nev. '94 *ABE, MASAYOSHI, Prof. of Mining, Imperial University Kyoto, Japan. '05 ? ACKER, E. O'C., Supt., Treatment Dept., Bethlehem Steel Co., So. Bethlehem, Pa. '86

Jan 1, 1910

By R. E. Grant

THE Cerro de Pasco Railway Co., owned and operated by the Corporation, is a common carrier whose chief functions are transportation of ore and concentrates from the mines at Cerro de Pasco to the smelter in Oroya, and haulage of coal from the coal mines at Goyllarisquisga to the coal washery at Fundicion. Connecting with the Peruvian Central Railway at Oroya, the C. de P. Railway maintains joint, daily freight and passenger service from Lima and the port of Callao to Cerro de Pasco, terminal of the C. de P. main line and gateway to the Huanuco Valley. Extending from Oroya to Cerro de Pasco the main line is a standard-gauge roadbed of 70-lb. rail, 132 km. long with a maximum compensated grade of 2.25 per cent and a curvature of 16°, climbing from an elevation of 12,272 ft. above sea level at Oroya, lowest station on the line, to 14,208 ft. at Cerro de Pasco. The highest point reached by the C. de P. is on the coal branch at Alcacocha where the rails are 14,385 ft. above the sea.

Jan 1, 1945

By G. M. Ritcey

Sulphuric acid leaching has been up to the present, the most popular of the leaching routes. Oxide ores are usually leached with sulphuric acid directly by dump leaching, as practiced at the Bagdad or Bluebird Mines in Arizona, or by vat leaching as done at Inspiration Mining in Arizona. Upgrading of the low-grade oxide ores by dump leaching followed by cementation of the copper from solution by scrap iron has been replaced by the leaching-solvent extraction-electrowinning route which results in a high purity product at the mill site at reduced production costs compared to previous practice. High-grade oxide ores, vat leached with H2SO4, can contain, for example, 25 g Cu/l and 25 g H2S04/,l, or higher concentrations of both, and are presently fed directly to electrorefining plants. Advantages of coupling solvent extraction-electrowinning with the low cost dump leaching instead of using cementation, are as follows (1): a) the production of high purity electrolytic copper rather than cement copper;

Jan 1, 1978

By David D. Rabb

Under the auspices of the Atomic Energy Commission, the Lawrence Radiation Laboratory of the University of California analyzed an experiment to provide information as to whether the chimney of broken rock produced by a deeply buried nuclear explosive could be "drawn" by conventional techniques. Since many low-grade disseminated ore-bodies occur in a granite media, the experiment took place in a granodiorite-quartz monzonite intrusive porphyry in the Nevada Test Site as a follow-up to the Department of Defense's Hardhat detonation in February 1962. For emplacement of the nuclear device, a 12 ¼ - in. pilot hole was reamed to a diameter of 44 in. and a depth of 950 ft in one pass using a Hughes multiple-cluster rotary bit. It was then cased to 36 in. ID. The center of the explosive device was located 938.85 ft below the collar. The yield of the device was predicted to be 5 kilotons, or an equivalent of 5000 tons of TNT; the yield was later confirmed by chemical means to be 5.4 kilotons.

Jan 3, 1964

By W. H. Bassett

ABOUT twenty-five years ago the copper industry had outgrown the Lake Superior production. The electrolytic copper producers had- their process well in hand and the industry was well started in the use of electrolytic copper, both for working into wire and sheet, and for the making of alloys. The trade knew that some brands of copper made good material and that other brands did not. There came together a group of men-a refiner, a rolling-mill man, and a manufacturer of electrical machinery-each of them desiring to know why there was a difference and what .it was. Much investigation was done with wire bars and cakes which involved ' chemical analysis, metallographic examination, physical tests and electrical tests. To find the influence of different kinds of copper in making brass 200 carloads of ingots were made into ,eyelet brass under careful observation; each carload was carefully analyzed and tested before used. The alloy was made and rolled under standard conditions and the results recorded.

Jan 1, 1924

By B. L. Averbach, M. F. Comerford, M. B. Rough

The volume fraction of ß phase was determined in a Ti-6Al-4V alloy by measurements of integrated diffraction intensities. The (0002), and (100)ß diffraction lines were chosen because this combination minimizes the errors resulting from preferred orientation. The difficulties arising from fluorescence radiation were eliminated by use of a diffracted beam monochromator. A specimen quenched from 1475OF (800°C) contained approximately 5 pct ß, but in specimens quenched from higher temperatures no ß was found. The ß phase formed during aging, and in specimens solution treated at 1570oF (855oC) approximately 10 pct ß was present after aging at 1000°F (540°C) for 24 hr. This ß appears to form by decomposition of martensitic a'. ThE kinetics of the reactions which occur during the heat treatment of titanium alloys are complex ' and not completely understood. It has been proposed that hardening occurs in some alloys' on aging by the precipitation of a transition phase w followed by the formation of the stable a and ß phases. It has been proposed for other alloys2 that the a' marten-site decomposes by precipitating finely dispersed a particles. Most investigations have been hampered by the difficulties of determining quantitatively the amounts of the various phases present. This paper is concerned with the measurement of the amount of ß phase by an X-ray method, similar to one developed for the determination of retained austenite. The principal new feature was the use of a mono-chromator in the diffracted beam in order to reduce the fluorescence arising from the sample. EXPERIMENTAL PROCEDURE The experiments were carried out on an alloy of nominal composition Ti-6Al-4V (actual weight percentages: 6.2 Al, 4.1 V, 0.02 Mn, 0.17 Fe, 0.005 H, 0.03 C, and 0.02 N). The material was received as 5/8-in.-diam centerless ground rods in the annealed condition. The heat treatments were carried out in a vacuum of approximately 0.03µHg. The X-ray intensity measurements were made on 3/8-in. thick discs. The surface was prepared by grinding off about 0.060 in. and electropolishing in a solution af 60 ml (70 to 72 pct) perchloric acid in 1000 ml glacial acetic acid with a current density of 0.5 amp per sq cm.q The X-ray determination is based on the proportionality of the diffracted intensity of each line to the volume fraction of the corresponding phase. In calculating the intensities for a powder sample it is assumed that a large number of grains con- tributes to the diffracted intensity and that the grains are oriented at random. The presence of preferred orientation introduces serious errors in the relative intensities. The material used in this investigation exhibited a strong preferred orientation, which could not be removed by heat treatment. Other investigators have also found that preferred orientation may be retained after phase transformations. Glen and pugh5 performed a detailed analysis of the randomness expected after several allotropic transformations, but stated that this is not observed. Burgers,6 and Burgers and Ploos van Amstel,7 found that, in zirconium, the original orientation is retained after two phase transformations. Newkirk and Geisler8 observed similar behavior in titanium. On the basis of this evidence, it appears that, in the absence of plastic deformation, textures present in annealed titanium alloys are retained. Heating an a-ß alloy to the all-ß region and subsequent cooling to room temperature do not make the orientation of the mar-tensite different from that of the original a phase. In the present investigation it was possible to take advantage of the crystallographic relationships involved in the martensitic transformation to minimize the errors associated with preferred orientation. The relative orientation for titaniu-m marten-site9 takes the form (0001), 11 (110)ß; [1120], 11 [lll]ß. The same relationship has been proposed for zirconium' and certain titanium-base alloys.10-12 Additional sets of approximately parallel planes have been determined for titanium-nickel alloys." The influence of preferred orientation can be minimized by comparing intensities from parallel planes in the two related phases. If it is assumed that each family of planes in a given phase is equally well populated, the effect of preferred orientation can be eliminated by using the normal multiplicity for the family of planes since each set of parallel planes is equally preferred for any orientation of the sample relative to the X-ray beam. The most suitable combination of reflections in the Ti-6A1-4V alloy appeared to be (0002), and (110)ß It must be recognized that the ß formed during aging of the Ti-6A1-4V alloy is a precipitate rather

Jan 1, 1960

By Samuel L. Hoyt

THIS paper gives a short account of plastic deformation as observed in single crystals of zinc, zinc having been selected for the experiments described herein because the phenomena are comparatively so simple and can be studied throughout such a wide range. It is hoped that the paper will serve to show the type of information which studies of single crystals afford and will contribute toward the solution of the general problem of metallic behavior. PRODUCTION OF ZINC SINGLE CRYSTALS The method of Czochralski,1 as modified by von Gomperz,2 was used to produce the crystals studied. The equipment is shown in Fig. 1. Molten zinc is held in a crucible at a temperature which is not far above its melting point, as measured by a pyrometer. A lava disk floats on ,the melt, and is provided with a central hole about 1 mm. in diameter. A glass tube, drawn into a capillary at the lower end, is suspended from a string which is wound up by an electric drive at the speed desired. At the start, the glass capillary is let down into the melt and the hoist is started.. The capillary brings up a small quantity of molten metal with it to a point just above the lava disk. At this point, a jet of hydrogen cools it and causes it to crystallize, with the result that a small crystal forms. As the hoisting is continued, more molten metal is drawn up, in turn to be solidified by the jet of hydrogen. This additional metal continues the growth of the crystal already formed, and a long, cylindrical crystal results. The speed of hoisting used was generally between 0.1 and 0.5 mm. per sec., and the crystals were from 4 to 6 in. long and about 1 mm. in diameter. By varying the conditions, crystals of quite different orientations were obtained and were used in the study of the phenomena to be described.

Jan 1, 1927

By Henry J. Sandri

The use of economic models for forecasting purposes is an inexact yet necessary tool for mineral decision making. One method not commonly used is cyclical analysis because of its "non-scientific approach". However, under certain circumstances a modified cyclical approach can provide useful insight to mining companies. The current paper discusses mineral modeling, the type of economic models and the use of cyclical forecasting for mining firms (not speculators) involved in precious metals.

Jan 1, 1984

By A. Ghosh, T. B. King

The kinetics of the discharge reaction: 20'- (in silicate melt) = O,(g) + 4e- at a platinum anode in lithium silicate melts have been studied al 1350°C by galvanostatic methods. Plots of the sleady-state overpotential, q, as a function of the logarithm of the current density, i, showed injlections and were linear only at high current densities. The value of the overpotential was influenced by bubbling gas through the electrolyte. The ocer potential was also studied as a function of time. The rise and decay of overpotential were very slow processes. At low current densities transport is the likely rate-controlling process but at high current densities passivation of the electrode, Presumably by an oxide film on the surface, seems to be a contributory functor. IT is well-established that molten silicates behave as electrolytes'5 and, except in a few cases,6 conduction is entirely ionic. Moreover, it is supposed that a possible, and perhaps predominant, mechanism for phase boundary reactions between metals and slags is similar to that in corrosion whereby anodic and cathodic processes occur at unrelated sites, the metal serving to conduct electrons.1'8 Thus electrochemical studies of some slag-metal reactions would seem to be a useful way to diagnose the rate-controlling steps in the overall reaction. The electrochemical method is, in principle, a better diagnostic tool than the direct chemical method for the following reasons: 1) The partial electrochemical reactions, which are simpler than the overall reaction, may be studied individually. 2) The rate of reaction can be controlled at will and independently of the concentrations of reactants. 3) Fast reactions can be studied by relaxation methods.' Esin and his coworkers5'10"12 have pioneered such studies in silicates and have deviloped some ingenious techniques. Not all of their findings, however. can be accepted without a good deal of further work. In this investigation, the kinetics of the oxygen discharge reaction: 202- (in silicate melt) = Oz(g) + 4e- [I] at a platinum electrode were studied by both steady-state and transient galvanostatic techniques. Interest in this reaction was first developed as a result of the findings of Fulton and chipman13 that the reduction of silica, in a silicate slag, by carbon, dissolved in liquid iron, is a very slow reaction. Subsequent work, for example, by Rawling and ~lliott,'~ has demonstrated that the reaction under these conditions must be slow, because the rate is limited by diffusion of oxygen in the iron to the metal-crucible phase boundary at which a CO bubble may be nucleated. Further work by Tarassof,'~ in which the reduction of silica by aluminum dissolved in copper was studied, has shown that under these conditions, where carbon monoxide evolution is not involved, control of the reaction rate resides in diffusion of silica in the slag phase. However, there is no practical way of inducing sufficient convection in the system to make it clear that the phase boundary reaction is indeed fast. The overall reaction of silica reduction involves the discharge of silicon ions at cathodic sites and oxygen ions at anodic sites. In the examples cited, the discharged ions are dissolved in a liquid metal. In the present study of oxygen ion discharge, gaseous oxygen may be evolved at high current densities or oxygen may simply dissolve, possibly as oxygen molecules, in the silicate at very low current densities. The discharge of an oxygen ion at an anode must, in silicates less basic than the orthosilicate composition, be preceded by a reaction in the vicinity of the electrode, such as: which makes oxygen ions available. Platinum was chosen as the working electrode since it is comparatively inert to oxygen and is, therefore, expected to come rapidly into equilibrium with the electrolyte and with gaseous oxygen. Minenko, Petrov, and Ivanova16 have measured the electromotive force at a platinum electrode in molten silicates as a function of the partial pressure of oxygen in the atmosphere, the concentration of oxide ions in the melt, and the temperature. They found platinum to behave as a reversible oxygen electrode. At two different oxygen pressures, Po2 (I) and Pq (11). the electromotive force is given by: where F is the Faraday constant, equal to 23,060 cal per v equivalent, indicating that the electrode reaction is as written in Eq. [I.]. Platinum has been similarly used in molten silicates by other inve~ti~ators. "'~~ In this investigation platinum was used only as an anode, since a current deposits other elements on its surface and changes its characteristics.

Jan 1, 1970

By John Birkinbine

(New Haven 'Meeting, February, 1909.) AWAKENED public interest in efforts to conserve natural resources will certainly be appreciated by the members of the American Institute of Mining Engineers, and a discussion upon conservation may well form a part of one of the Institute meetings, for the records of papers and discussions which appear in the 38 volumes of its Transactions are replete with evidence of effort's in this direction. Every process which reduces the fuel consumed or the power applied per unit of product; every utilization of waste material, or employment of that formerly rejected, to obtain something of value ; every feature of construction or operation which lessens the labor required or increases the output per employee, is an advance in the direction of true conservation. This may not appear from the records of late conferences or from published articles, in which the effort seems to be concentrated upon reducing the consumption and presenting to the people of the country estimates of exhaustion of natural resources. I rejoice in the awakening of public interest in a matter so important for the present and future welfare of our nation; I appreciate the possibility of much good following conferences of the Governors and delegates from various States and from national societies; and I recognize the interdependence, not only of different States, but of contiguous nations. In fact, the marvelous development of transportation by land and by water, and the decreasing rates at which commodities can be moved great distances, have in many cases practically obliterated geographical boundaries, and nearly every country on the globe can either market its product in other lands or draw upon them for raw or manufactured materials ; hence, conservation is an international subject.

Apr 1, 1909

By R. Maddin, C. H. Mathewson, W. R. Hibbard

According to conventional crystal mechanics, a face-centered cubic single crystal slips on the system {111} <110> which receives the highest shear stress in terms of the stated orientation of the stress axis of the crystal.l However, in brass, the slip process is never as simple as this conventional analysis indicates. There is always a second cooperating plane which contains the same slip direction as the primary plane.2&apos;3 There is still another cooperating slip system commonly called the conjugate system3 previously observed to function with considerable lag only after the rotation due to the action of the first plane had produced a symmetrical condition of equal shear stress on the two systems. In the 1943 Campbell Lecture,4 a slip mechanism was outlined in which the {111) planes moved step-wise in two adjacent <112> directions integrating into the <110> slip direction. "... the slipping process would be visualized as a succession of steps 30" to the right and left of the resultant, microscopically observed, slip direction; a first step setting up the twinned configuration in the single spacing involved and an ensuing slip returning the atoms to the untwinned configuration while completing a fully integrated <110> movement."4 This process is shown diagrammatically in Fig 1 which shows two close packed layers of atoms at a slip site. A movement of the full circles through the "valleys" into the adjacent sites would produce a twin configuration with respect to the open circles. The term, "twin fault," seems most appropriate to define this faulted condition of the lattice. Annealing twins in face-centered cubic metals may arise from preformed nucleii which could be described as twin faults produced by the first movement of this two stage slip process. However, it is clear that this kind of slip does not take place so as to embrace a measurable number of adjacent planes because careful X ray examination has not conclusively shown the existence of ponderable twin lamellae (as in the case of Neumann bands in the body-centered ferrite). In view of the imponderable character of these hypothetical twin faults, the search for evidence of their existence seems restricted to indirect methods. The most obvious experimental technique serving this purpose is the determination by micrographic and X ray methods of the alignment of the composition planes of annealing twins with the former slip planes in axially strained and recrystallized single crystals. In previous attempts of this sort not all of the annealing twins could be traced to slip planes known to be operative in the conventional sense and hence evidence appeared negative or inconclusive. With the discovery of additional slip systems2&apos;3 operating in conjunction with&apos; the major system of highest resolved shear stress in axially strained brass it became apparent that the simple technique outlined above might be re-employed with more gratifying results. If, on annealing single crystals of alpha brass previously strained in tension, twins are found with their composition planes parallel to all three operative slip planes and with no participation of the fourth plane there is good evidence in favor of the existence of twin faults and of the two stage slip process. Experimental Procedure and Resuits Single crystals of alpha brass of the 70-30 composition were grown by solidification from the molten state.

Jan 1, 1950

The Pinson Mining Co., which will start production in very early 1981, is the fourth Carbon-In-Pulp plant to be put into operation in the United States. The property is located in Humbolt County, Nevada, 38 km (24 miles) northeast of the town of Golconda. The famous Getchell Mine was also near Golconda and was the site of one of the early Carbon-In-Pulp plants in the 1940s. The deposit was discovered in 1971 by Reno based Cordilleran Explorations, which is founded by a consortium of Canadian mining companies. Cordilleran is a partnership consisting of John Livermore and Peter Galli. In 1972 a second but smaller deposit, called "Preble", was discovered at a location 15 miles south of Pinson. During 1980, a decision was made to place the Pinson deposit into production and Pinson Mining Company was formed. Ownership of Pinson is vested in Lacana Mining Inc. , Rayrock Mines, Inc. , Siscoe Metals, Inc., John S. Livermore, Peter E. Galli and Donald M. Duncan. Three distinct but connected ore zones occur at Pinson. Combined reserves of milling ore total 3, 200, 000 tons at an average (undiluted) grade of 4. 12 g per mt (0. 12 oz per st) Au. Initial mining will be from "A" zone which contains 1, 500, 000 tons with an average (undiluted) grade of 5. 8 g per mt (0. 17 oz per st) Au. An additional 5, 500, 000 tons of low grade ore will be mined from the Pinson deposit and processed by heap leaching. Mining reserves at Preble total at least 1, 500, 000 tons grading 2. 7 g per mt (0. 08 oz per st) Au. Production plans for the Preble deposit have not been formulated at the date of writing. Gold mineralization at both deposits is finely disseminated as sub micron sized particles. The ore at Pinson is structurally controlled and occurs in an Ordovician limestone-siltstone unit. Much of the ore has been silicified to a jasperoid. The ore zones have been entirely oxidized. Preble ore occurs in the Cambrian formation in a carbonaceous, limey shale. Only the upper part of the Preble is oxidized and amenable to conventional cyanide leaching. The Pinson ore body is adjacent to the mouth of Granite Creek in the Osgood Mountains at an elevation of 1, 615 m (5, 300 ft) with the mill being 1. 2 km (3/4 mile) from the mine at an elevation of 1, 495 m (4, 900 ft). Mine development work began in May of 1980 with ore being stockpiled for later processing. Pertinent factors affecting

Jan 1, 1981

Ahrenholz, Herman William, Jr., Student, Lehigh Univ Bethlehem, Pa. &apos;35 Allen, Carl A., Student, Colorado School of Mines Golden, Colo. &apos;35 Allen, Paul W., Student, Mass. Inst. of Tech Cambridge, Mass. &apos;35 Allen, R. M., Jr., Student, Virginia Polytechnic Inst., "G" Co Blacasburg, Va. &apos;35 Amberger, K. H., Student, Michigan College of Min. & Tech Houghton, Mich. &apos;35 Andersen, Burton Lee, Student, School of Mines, Univ. of Washington Seattle, Wash. &apos;35 Anderson, Joseph S., Student, Univ. of Texas El Paso, Tex. &apos;35 Anderson, R. C., Student, Univ. of Washington Seattle, Wash. &apos;35 Ansel, Gerhard 627 Clyde St., Pittsburgh, Pa. &apos;34 Anutta, Frederick P., Student, Michigan College of Min. & Tech Houghton, Mich. &apos;35 Apsouri, Constantin N., Graduate Student, Univ. of Arizona Tucson, Ariz. &apos;35 Arakelian, Haig Mark, Student, Mass. Inst. of Tech Cambridge, Mass. &apos;34 Archer, George K 1420 Court Pl., Denver, Colo. &apos;34 Argall, George O., Jr., K. E. House Golden, Colo. &apos;35 Argiielles, Alfredo, Student, Univ. of Texas El Paso, Tex. &apos;35 Atwater, Ralph, Student, South Dakota School of Mines Rapid City, S. D. &apos;35 Austin, Robert B., Miner, Page Mine, Federal Min. & Smelt. CoSpokane, Wash. &apos;34

Jan 1, 1934

By T. A. Rickard

Slovenliness is as reprehensible in words as in clothes. Much writing that we recognize as poor in style is merely sloppy. Just as some students postpone the necessary shave or forget to change their collars, so young engineers in writing drop their articles, definite and indefinite, or omit prepositions where they are required, possibly to compensate for these they use unnecessarily The work will begin [on] Saturday. The work will begin [on] Saturday. `Influenza seriously affected many mines [during] the last three months. Flotation in America [during] the last two years has made tremendous strides. Construction of the mill started [on] August 12, 1915, at which time 75% of the excavation was completed. The idea I wish to convey is [that] there are mineral deposits to which the present law applies badly. For this reason, if there was [for] no other, the ownership of the ore below and [of] the surface above should go together. When a unit of mapping is furnished, be the unit a claim or [a] group of claims, it is necessary .. . A fully stocked store was started in Park City and all employees [were] sold merchandise on a strictly cost basis. The word "merchandise" is left without government or agreement. I suggest: ". . . and merchandise] was sold to all the employees on a strictly cash basis.". The verb `be&apos; is serving concurrently both as a principal and as an auxiliary in the following: At first the work was interesting and [was] liked by most of the men. The sulphide ore was more complex or [was] milled at an increased cost. The failure to repeat tie auxiliary verb in successive clauses is a common error, as in The filter is filled with liquid allowed to empty, and then ignited.

Jan 1, 1931

By D. Atkinson, C. Bodsworth, I. M. Davidson

A geometric model of interstitial solid solutions, which has been used previously as a basis for the prediction of carbon activities in Fe-C austenite, is shown to serve also for the calculation of nitrogen activities in Fe-N austenite. The model has been developed to enable predictions to be made of the activities of an interstitial element in the presence of two host atom species. The activities calculated via the model are shown to be in satisfactory agreement with the measured values in the austenite phase for carbon in Fe-C-Co, Fe-C-Cr, Fe-C-Ni, Fe-C-~n, Fe-C-Si, and Fe-C-V alloys and for nitrogen in Fe-N-Ni alloys. The effect of the second substitu-tional solute on the logarithm of the activity of the interstitial element is expressed as the product of a constant mad the atomic concentration of that solute. The constants so derived we related to the thermo-dynamic interaction coefficients which describe the effect on the activity coefficient of carbon of an added solute element. In recent years the thermodynamic activities of carbon and nitrogen in the single-phase austenite field have been determined for iron binary alloys and for several iron-base ternary alloys. In order to extend the use of these measurements, it is desirable to be able to predict with reasonable accuracy the activities of the interstitials at compositions and temperatures other than those which have been measured experimentally. In all the systems studied to date, the interstitial elements do not conform to ideal behavior. Hence, the available data cannot be extrapolated or interpolated using the simple thermodynamic concepts of solutions. Several models have, therefore, been formulated for the purpose of predicting the activity of an interstitial element in the presence of one species of host atom. These models can be divided into the geometric1"5 and energetic6-&apos; types. The former group is based on the assumption that at low concentrations the activity of the interstitial species is determined by a composition-dependent configurational entropy term and an excess free-energy term which is temperature-dependent but independent of composition. The purpose of this paper is to show that the treatment, based on a geometric model, can be extended to enable predictions to be made of interstitial activities in the presence of two substitutional host atom species. THE CONFIGURATIONAL ENTROPY OF MIXING ICaufman5 has shown that the configurational entropy, S,, for a binary solution comprising of a host atom species, A, and an interstitial species, I, can be expressed as: where NI is the atom fraction of the interstitial species, R is the gas constant, and (2 - 1) is the number of interstitial sites excluded from occupancy by the strain field around each added interstitial atom. The number of interstitial sites per host atom, p, is unityg for the fcc austenite solutions considered here. The configurational entropy of mixing for a ternary solution comprising two substitutional atom species, A and B, and one interstitial species, I, can be derived similarly. Let the number of atoms per mole of each of these species in the solution be represented by «a, ng, and nI. From geometric considerations, it is improbable that the addition of a few atom percent of a second host atom species will change the type of sites (i.e., octahedral) in which the interstitial atom can be accommodated in the austenite lattice. At higher concentrations (determined largely by the relative atomic radii of the atomic species present and any tendency to nonrandom occupancy of the host lattice sites) other types of interstitial sites may become energetically favorable. Restricting consideration to compositions below this limit, for 1 = 1 the number of suitable interstitial sites is given by (n + nB). However, if each interstitial atom excludes from occupancy (Z - 1) additional sites, the total number of sites available for occupation is reduced to (n + ng)/Z. The number of vacant interstitial sites is given by: The total number of recognizable permutations of the atoms must include the recognizable, different configurations of the A and B atoms on the host lattice. Assuming that these arrangements are purely random, and are not affected by the presence of the interstitial species, the total number of recognizable permutations in the ternary alloy is given by: The configurational entropy is obtained by expanding, using Stirling&apos;s approximation, and collecting like items, as:

Jan 1, 1969

By A. Aly Selim

A computer model was developed to calculate the fragmentation cost for in situ leaching operations as a function of the blast design and deposit parameters. The model is based on blasting an ore zone only or an ore zone plus overburden by either a coyote blast or a vertical blasthole system. The model calculates the blast design parameters and the fragmentation cost based either on a user input powder factor value or on a powder factor calculated by the model as a function of the overburden height and the ore zone thickness. Examples of blast design parameters calculated by the model are the number and spacing of blastholes for a vertical blasthole system and the number and spacing of crosscuts for a coyote system. The model also calculates the total amount of explosives, the detonating cord length, and the number of primers. The cost of blasthole drilling can be calculated by the model based either on purchasing and operating a drill or on a user input value of the contracted cost of drilling. Application of the model to an example ore deposit showed that the vertical blasthole systems were more economical than the coyote system when there was no overburden and the deposit had an average ore thickness less than 45 meters. With no overburden and ore thickness greater than 45 meters, the vertical blasthole system was either more or less expensive than the coyote system depending on the number of levels used in the coyote system. With overburden, the coyote system was less expensive than the vertical blasthole system for blasting either the ore only or the ore plus the overburden. A coyote blast will usually produce larger particle sizes than a vertical blasthole system. Larger particle sizes can result in lower copper recoveries so that a less expensive coyote blast may not improve the overall economics of an in situ leaching operation. Blasting the ore zone only was generally less expensive than blasting the ore plus the overburden by either blasting system. Also, for the example considered, the coyote system costs were less sensitive to changes in overburden thickness and powder factor while the vertical blasthole system costs were less sensitive to changes in ore thickness.

Jan 1, 1977

Aamot, Olav Crone, (M&apos;29) Chem. Engr., Elektrokemisk, Raadhusgt. 23, Oslo, Norway. Abadilla, Quirico A., (M&apos;3S) Min. Engr., Dir., Bu¬ reau of Mines. Manila, P. I. Abbott, Agatin Townsend, (J&apos;40) Jr. Engr., Phelps Dodge Corp., Morenci Branch, Morenci. Ariz. Abbott, Clarence E., (M&apos;04) Civil Engr., V.P., Ten¬nessee Coal Iron & R.R.. Co., 1542 Brown -Marx Bldg.. Birmingham, Ala. Abel, Raymond L., (M&apos;28) Chem. Engr., Command¬ing, Officer, Pittsburgh Chem. Warfare Procurement Dist., American Bank Bldg., Pittsburgh. Pa. Abel, Walter D., (M&apos;32) Alin. Engr.. Div. of Cor¬porations, State of Calif., 403 California State Bldg., Los Angeles, Calif. Abele, Louis T., (M&apos;31) 423 3rd Ave., Decatur, Ga. Abell, Leo M., (M&apos;31) Mill Supt. & Met., Emperor Gold Min. Co., Led., Vatnkoula, Fiji Islands. Abernathy, G. E., (M&apos;38) Geol., Kansas State Geol. Survey, Pittsburg, Bans. Abernathy, Jack H., (M&apos;40) Peer. Engr., c/o Superior Oil Corp., National Bank of Tulsa Bldg., Tulsa, Okla. Aborn, Robert H., (M&apos;10) Asst. Met., Research Lab., U. S. Steel Corp., Lincoln Highway, Kearny, N. J. Abraham, A. W., (M&apos;39) Peer. Engr., Richfield Oil Corp., 555 S. Flower St., Los Angeles, Calif. Abramowitz, William L., (J&apos;40) Chem., Industrial Inventions, Inc., 103 Foster Se., Peabody, Mass.

Jan 1, 1942