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Grad, the abbreviation for Graduate Resume Accumulation and Distribution, is a computerized information retrieval system operated on behalf of college placement officers around the country by the non- profit College Placement Council, Inc. Grad is free to all engineering candidates (regardless of the number of years of experience) and is a means of getting together college alumni who are seeking new employment and prospective employers. Who is Qualified? Candidates must have at least a bachelor's degree from a four-year college or university, or. in lieu of this, be accredited by a professional institute such as AIME as a full Member.

Jan 1, 1970

By Stephen E. Erickson

MORE and more hydrocyclones are being installed in beneficiation plants. This recent rapid increase is of special interest in the history of beneficiation, since development of the hydro- cyclone appears to have swung in a circle. To avoid any chance of confusion, it would be well first to review the accepted definitions. The size of a cyclone is expressed as the diameter of the cylindrical section. Size of the inlet orifice- which may be circular, square, or rectangular- is expressed as a diameter, or as width and length, or as an area (in square inches). The angle of a cyclone is expressed as the total included angle. The overflow or finest classification fraction leaves the cyclone through the vortex finder. The underflow or coarsest classification fraction leaves through the apex opening.

Jan 8, 1957

By H. H. West

Modern mining is vitally concerned with the prompt, efficient movement of great quantities of bulk materials. It is not surprising, therefore, that intensive efforts are being directed toward improving effectiveness and reducing costs of materials handling systems. Historically, the operation of removing bulk material from a moving conveyor and depositing it in utilization or storage areas has been a high cost segment of the materials handling system. Since this operation is often performed by belt trippers, considerable attention has been focused on improvement of these devices. Frequently, the greatest opportunity for improving performance of these devices is the incorporation of remote or automatic control systems. This article describes tripper control systems developed by Kennecott Copper Corp. and explains the control philosophies used in designing these systems.

Jan 3, 1963

By William Hamilton Merritt

At the Atlanta Meeting in October, 1895, a short paper was presented by Mr. R. W. Leonard on the " Assay of Auriferous Ores and Gravels by Amalgamation and the Blow-pipe" (Trans., xxv., 645), embodying the results of some very conclusive tests as to the value of the process. His arguments regarding the desirability of the process appear to be indisputable, but the practicability of the field-outfit used by him is open to question. The Province of Ontario, in which Kingston is situated, is still largely unexplored; and at the Kingstoil School of Mining we give much attention to the instruction of prospectors and the testing of ores. To this end, not only is there a small mill (to which Mr. Leonard alludes) attached to the school, but prospectors' classes

Jan 1, 1897

The Year Book of the Institute is mailed with this Bulletin. Its membership lists, both alphabetic and geographic, are corrected to Jan. 1, 1918, but its list of officers is revised inn accordance with the elections in February, 1918. The amendment to the Constitution, relating, to qualifications for membership, adopted at the same time, is also inserted in its proper place. We would call attention to the Honor Roll, heading the list of membership. This includes the names of those whom we know (in February, 1918) to be on active military duty, as well as those who are rendering emergency service to the Government in other branches. We are aware that the list is not complete, and shall be grateful for information as to any omissions or corrections. Because of the rapid movement of the military members, their addresses have been omitted from the alphabetic list. Mail addressed to such members, and sent to the office of the Institute, will be forwarded to the best of our information at the time.

Jan 3, 1918

ALTHOUGH I have told you before (in the chapter on making the main mould for guns) how to support the core, I wish to repeat it here briefly and in a more orderly fashion, so that you may understand it better. For it is a thing of great importance to the profit of the owner as well as to the honor of the master, because he who does not locate the core in the middle makes the gun weak and incapable of shooting straight, and shows great lack of skill as a master. In short, it is very necessary to do this well. The first of these methods that I described to you is an iron, one dito wide, made into a ring which has four arms in a cross, or sometimes three. This is put in the mould where [88v] the last cornice begins, one palmo or half a braccio from the foot. Secure it in the middle of the diameter,

Jan 1, 1942

We are advised by Carrington Phelps, Secretary of the professional Classes War Relief of America, having offices at 33 West 42d Street, New York, that this organization is now prepared for active relief of professional men who have enlisted in military service or are assisting the Government in the civil service or in civil life, at the sacrifice of their usual sources of income. The organization has found that the main obstacle to such relief is the hesitancy of this class of persons to make known their needs. Relief cases have to be sought out; the organization has already found some but has asked the cooperation of the Institute to assist in finding as many more as may exist. It is suggested that the Institute can render useful service in this connection, first, by informing our members of this feature of war relief, by being on the alert to report those needing relief, and to make all possible inquiry after such cases. It is further desired that information as to all such cases be forwarded immediately upon their discovery.

Jan 3, 1918

By P. R. Sperry

A METHOD was recently devised to indicate two or more successive stages of the migration of grain boundaries in aluminum, and to record the direction of the migration. This technique was used for the study of the various types of boundary migration occurring in high purity aluminum.' The method employs alternate annealing and electrolytic etching treatments, repeated as many times as desired. All successive sets of grain boun- dary positions revealed by the various etches appear superimposed on each other. The last etch is designed to leave an oxide film on the surface which is optically anisotropic. The orientation of the oxide film at each point is determined by the orientation of the underlying aluminum grain. When viewed with polarized light using crossed nicols and a Biot-Klein quartz plate, grains with differing orientations appear in different colors, as described by Hone and Pearson.' The last boundary positions are revealed by these color differences. The first step of the process is to obtain a desired starting grain size by annealing, for example, if high

Jan 1, 1951

By P. K. Lucke

ONE of the interesting features connected with the great continental uplift, which formed the table land of Mexico, is the great depth to which oxidation and secondary enrichment of orebOdies occurred. This table land lies at altitudes ranging from 4000 to. 7000 ft. (1219 to 2133 m.) above sea level. Several cases could be cited of oxidized zones in copper and lead mines which reached depths of upward of 1500 ft. (457 m.) below the surface, and it is universally admitted that the oxidized zone in a mine is limited by the permanent water level. FIG. 1. Mexico, however, like many other countries in which deserts occur, is visited at rare intervals by tremendous floods, which sometimes cause variable water levels over long periods. The following cases bear out the idea, and lead to interesting conclusions of commercial value. My paper demonstrates that carbonates of ores may occur below water level and sulphides above, and I will endeavor to explain the causes of the phenomena in certain specific instances.

Jan 6, 1918

By J. W. Downey, M. V. Nevitt

DURING the course of the present investigation of alloy phases involving transition metals, phases were found in the systems Os-Ta, Os-W, and Ir-Ta. The (Os, W) phase was also recently reported by Raub.1 Pertinent information is given in Table 1. The approximate composition range of sta- bility was determined metallographically on arc-melted buttons that were annealed 72 hr at 1200°C and water quenched. X-ray powder patterns were obtained with a 114.6 mm diam powder camera using filtered copper radiation. The composition for (Os, W) given by Raub (66 atomic pct W) is in agreement with the composition range reported here. However, the lattice constants reported by Raub are: a0= 9.913±0.007, c/a= 0.515. The reason for the discrepancy between the lattice constants reported by Raub and those given here is not known. Acknowledgments The authors wish to thank M. H. Mueller and H. W. Knott for assistance with the X-ray diffraction work, and R. A. Morris for the preparation of the alloys. This paper is based upon work performed at the Argonne National Laboratory under the auspices of the Atomic Energy Commission.

Jan 1, 1958

By Willard P. Ward

IT is the object of the present paper to bring to the notice of members of this Institute, the results of experiments made during the past six months in the manufacture of the alloys of iron and manganese in the blast-furnace. The ores at hand and available for the purpose were brown hematites, containing but a very small percentage of manganese, and various manganese ores containing a small percentage of iron. It is hardly necessary here to call attention to the statements regarding the production of iron-manganese alloys from such ores, which are given by all the well-recognized authorities on metallurgy. Suffice it to say, in a few words, that they hold that the operation is practically impossible, and that in the use of oxides of iron and manganese, mechanically intermixed in the same ore, much difficulty has been found in producing spiegeleisen. Spathic ores, containing manganese chemically combined, are alone recommended for the production of spiegel, and even then it is said that well-managed furnaces produce only about 75 to 80 per cent. of spiegel, the balance of the production being white laminated pig or gray iron.

Jan 1, 1876

W. H. BLAUVELT (author's reply to discussion *).-The prevention of smoke from byproduct-oven plants is not as simple as would appear from Mr. Moss's statement. All well designed byproduct-oven plants are equipped with ample exhauster capacity, and the suction on the ovens is controlled by highly sensitive pressure governors that control the pressure within a fraction of a millimeter. Of course, this apparatus can get out of order, causing the batteries to smoke, but this does not often happen. As stated by Mr. Thompson, the smoke produced is made almost entirely during the time of charging the ovens, when they are cut off from the hydraulic main. The amount of smoke that escapes at this time is extremely small, compared with -the amount produced by a beehive-oven plant, but the mechanical difficulties in preventing any escape of smoke at charging time are considerable. Several devices are in operation at a number of plants which collect most of the smoke made during charging and several devices are being worked on for its complete

Jan 12, 1918

By J. J. Bodmer

ALTHOUGH the similarity between puzzolana, or trass, and blast-furnace slag, as seen by comparison of the analyses, is a well-known fact, blast-furnace slag has not been used commercially as a substitute for those cementing materials. The reason, the writer apprehends, lies in the fact that unless such slag is disintegrated or subdivided by rolls, the process must either be too costly, or the material is not in a fit and proper condition for the purpose. In order to produce a reliable slag cement, the slag must be ground together with the lime into an impalpable powder. The subdivided slag must, therefore, be perfectly dry, and, at the same time, friable. The stronger the hydraulic properties of the lime, the more reliable the slag cement will be, and practice has proved, that the slag from a gray-iron furnace gives the best results. The slag cement which has given the results shown in the annexed table, under pressure tests, was composed of six parts of slag, from a blast-furnace producing No. 3 foundry iron, and one part of lime, of medium hydraulic properties. The above-described class of cement bears storing as long as most Portland cements, and the cheapness of its production is self-evident.

Jan 1, 1874

By Willard P. Ward

It is the object of the present paper to bring to the notice of members of this Institute, the results of experiments made during the past six months in the manufacture of the alloys of iron and manganese in the blast-furnace. The ores at hand and available for the purpose were brown hematites, containing but a very small percentage of manganese, and various manganese ores containing a small percentage of iron. It is hardly necessary here to call attention to the statements regarding the production of iron-manganese alloys from such ores, which are given by all the well-recognized authorities on metallurgy. Suffice it to say, in a few words, that they hold that the operation is practically impossible, and that in the use of oxides of iron and manganese, mechanically intermixed in the same ore, much difficulty has been found in producing spiegeleisen. Spathic ores, containing manganese chemically combined, are alone recommended for the production of spiegel, and even then it is said that well-managed furnaces produce only about 75 to 80 per cent. of spiegel, the balance of the production being white laminated pig or gray iron.

By William Braden

This paper is presented in the hope that it will be instructive in view of the future large expansion of the mining industry in the west-coast countries of South America. There is a more or less general impression that the Spanish-American workman is inferior to the American, but after some years of experience and observation I doubt the correctne~s of this view. Taking into consideration all the elements which make for efficiency of labor, it has been found, particularly in Chile, that under proper organization native labor yields as much, man for man, and more, dollar for dollar, than in the Western United States. If a manager is willing to accept unreservedly the costum-bres del pais, without combating intelligently and patiently the ones tending to inefficiency, he should expect no better results than he deserves. He must conscientiously insist that a " square deal" be given and exacted; that liquor be excluded from camp as far as possible; that comfortable quarters and other uplifting elements of life be provided; and that past and existing methods and customs shall not be over-ridden rough-

Jan 1, 1910

By H. Hanemann

Discussion of the paper of H. HANEMANN and PAUL D. MERICA, presented at the New York meeting, February, 1916, and printed in Bulletin No. 108, December, 1915, pp. 2371 to 2385. JOHN A. MATHEWS, Syracuse, N. Y.-I should like to ask the authors if there is any evidence of chemical change resulting information of, alpha iron from the gamma crystals found in nickel steel of high nickel content when stressed beyond the elastic limit, similar to the effect produced by drastic cooling. Would the stresses mentioned and the drastic cooling both result in an increase in magnetic induction? I would also like to ask the authors if they have made a test of the hardness. It would be very interesting to see whether the hardness decreased under the conditions of stress, as might be the case if alpha iron were produced. PAUL D. MERICA, Washington, D. C.-While it is impossible to state absolutely, it is my belief that the effect of deformation is approximately the same as, that of -drastic cooling, but we did not make a test, of the hardness.

Jan 5, 1916

By Marshall B. Standing, Donald L. Katz

DENSITY data are reported on 15 saturated hydrocarbon liquids in the range of 35° to 250°F. and 1000 to 8220 lb. per sq. in. The apparent liquid densities of methane and ethane are shown to vary with the density of the system in which they are present. A method is proposed whereby the densities of liquid hydro- [ ] carbon mixtures containing both methane and ethane in solution may be computed at elevated temperature and pressures within the accuracy of usual engineering computations. A method of computing the shrinkage of crude oils based upon the gas-oil ratio, gas analysis, and crude gravity is outlined. INTRODUCTION The densities of naturally occurring liquid hydrocarbon mixtures are important [ ] in many petroleum engineering computations. Calculation of the shrinkage of a subsurface sample of crude oil as the natural gas is evolved is one example of the use of liquid-density data. Sage, Hicks, and Lacey5 have presented a method of computing the density of hydrocarbon liquid mixtures based on partial molal volumes. Katz1 has indicated a method based on the principle of additive

Jan 1, 1941

By Valentine Garfias

THE various phases of the Mexican oil industry have received so much publicity that there is little to add to the discussion of present and future production, extent and importance of prospective fields, and status of petroleum legislation, to mention but a few of the angles of the Mexican oil problem. However, out of this wealth of information, which is generally of contradictory nature, the average petroleum man is at a loss to know something definite regarding the various questions involved so, keeping the foregoing in mind, it has been the writer's aim to record in a concise form the most reliable and up-to-date information regarding the salient features of the Mexican oil situation. PRESENT STATUS OF MEXICAN OIL INDUSTRY Production During 1921 The Mexican oil fields, during 1921, produced in round numbers 203,000,000 bbl. of which 176,000,000 bbl., or 86 per cent., were exported, the bulk of -these exports, or about 73.3 per cent., going to the United States. The Mexican exports were divided by grades as follows: Light crude, 47.0 per cent.; heavy crude, 22.0 per cent.; tops, 3.5 per cent.; fuel oil from light crude, 24.0 per cent. The balance, or 3 1/2 per cent., includes the bunker fuel shipments and the coastwise trade in Mexico, which is not classified as to grades. The figures show that, in importance, the light-oil fields from about 755 per cent. of the Mexican petroleum industry.

Jan 4, 1922

By Shiou-Chuan Sun

Most previous work on sedimentation of coal1 and mineral2,3 suspensions has been conducted in graduated 1-liter glass cylinders of 6-cm diam. With this type of large container it is often difficult to see through the suspension and tedious to perform a large number of tests. Furthermore, the heavy glass walls and the graduation lines of glass cylinders cause internal and stray reflections, respectively. To obviate these difficulties, an Atlab Emulsion Viewer from Arthur H. Thomas Co. was adopted as an alternative apparatus. Equipment: The viewer,4 shown in Fig. 1, consists of: 1) a stainless steel frame rack holding 21 flat-bottom Nessler tubes or an ungraduated replica 1.64 cm ID and 1.80 cm OD, 2) a movable masked 150-w lumaline lamp behind the tubes, and 3) a scaled glass panel with 100 vertical divisions in front of the tubes. The tubes are snugly held by springs in slots formed by spacer bars, which also serve as shields to eliminate stray light. The lumaline lamp is mounted behind a slit in a movable housing so that it can be positioned behind the suspension to be examined. The lowest or 100-division line on the front glass plate is leveled with the upper side of the bottom of all tubes. The scaled portion of each tube, roughly 19 cm high and 40 ml in volume, is used to study coal and mineral suspensions.

Jan 1, 1959

By R. S. Dean

ALTHOUGH it is obvious that in any flotation process we must have a froth, in recent years the development of collecting reagents has caused the possibilities of better frothing agents to be overlooked. Some investigators have even gone so far as to say that the number of satis-factory frothing agents was sufficient. A little consideration will show, however, that the reagents available in the past were far from ideal frothers. The properties of an ideal frother for flotation work may be set down as follows: 1. It. must form in low concentrations a copious but not too persist-ent froth. 2. It must be insensitive to hydrogen-ion concentration of the pulp; that is, it must froth equally well in an acid or alkaline medium. 3. It must be insensitive to salts, even in high concentration. 4. It must be absolutely noncollecting to both sulfides and nonsulfides. 5. Its frothing properties must not be affected by collecting reagents, including soap, the most generally used nonsulfide collector. 6. It must readily emulsify and disperse any insoluble collecting agent that is likely to be used. Clearly the existing frothers do not qualify. Pine oil, for example, is an acceptable frother for many purposes but if used in soap flotation a delicate balance between pine oil and soap must be struck because, as pointed out by Coghill1, these two reagents are incompatible in certain concentrations. The objections to soap itself as a frother are obvious, and the cresols and their substitution products all have some collecting Dower and very little emulsifying power.

Jan 1, 1935