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By R. G. Hudson, L. Yang

In electrochemical separation of metals, it is necessary to control the potential applied between the electrodes so that only the desired electrode reactions can occur. A knowledge of the minimum potential needed for a given electrode reaction to take place continuously is therefore pertinent to the success of the process. In molten chloride systems at high temperatures, activation polarization is believed to be small,1,2 so the minimum potential needed for the electrolytic decomposition of a molten metal chloride MC1n (n = valence of the metal ion) is therefore essentially the equilibrium electrode potential E of the metal-chlorine galvanic cell in the solution. If the decomposition products are pure M and chlorine at a pressure of p atm, E*Eo-rt/nf in [i] Since EO (the standard electrode potential of MCln) is a constant at a given temperature and R (the gas constant), and F (the Faraday's constant) are all constants, the variation of E with the electrolytic bath conditions is largely determined by the effect of the latter on the activity of the metal chloride amcln (standard state = pure MC1,). Measurement of E and study of how amCin varies with temperature and concentration, the nature of the solvent, and that of the coexisting solutes are therefore pertinent in the selection of optimum operating conditions for the electrochemical separation of metals. Because of its low melting point, high decomposition potentials of its components, and the low solubility of heavier metals in it, the LiC1-KC1 eutectic melt is a useful solvent and has been used in the electrodeposition of Mo,3Ce,4 and u5 metals. Senderoff and Brenner3 measured the potentials of Zn/Zn++, Fe/Fe++, Cu/Cu+, Mo/Mo+++, and Ag/Ag+ against an Ag/AgCl (pure) reference electrode at 600°C and a concentration of 4.1 mole pct of each chloride and came to the conclusion that complex ion formation occurred in some of the melts. Laitinen and LiUe gave an electromotive force series at 450°C for a number of {Metal/Metal ions (unit activity)) electrodes in LiC1-KC1 eutectic melt, the {pt/pt++ (unit activity)) electrode being chosen as the reference. Walker and Danly7 studied the ther-modynamic properties of NiC12 in LiC1-KC1 eutectic melt over a wide range of temperatures and concentrations by measuring the electrode potential between a nickel electrode and a chlorine electrode in the melt. Since potential measurements made by using the chlorine reference electrode are of more direct significance both in the study of electrochemical separation and in the evaluation of the thermodynamic properties of the melt, it is therefore decided to measure the electrode potentials of cells of the type {M/MCin (mole fraction = N) in LiC1-KC1 eutectic melt/Cl2 over a range of N values and temperature for a number of metal chlorides. The results should indicate the order by which the various metals plate out on the cathode and how this order is affected by temperature and the concentration of the metal chloride in the solu-

Jan 1, 1960

By T. E. Tietz, J. E. Dorn

Activation energies for creep of copper at intermediate temperatures, where crystal recovery was negligible, were determined by the simple technique of rapidly alternating the test temperature between and T2 (T2 = TI + about 10°K) throughout a constant stress creep test. The activation energy for creep H was found to be 37,000± 3,000 cal per mol, independent of stress and strain. The same creep laws as have been previously established for high temperature creep were found to be valid for creep at intermediate temperatures. But the AH was found to be lower than that for self-diffusion in the intermediate temperature range whereas it is known to be equal to that for self-diffusion at high temperatures. IT is now well established that creep at high temperatures can be correlated by the functional relationship'-" e = f(?) s = constant [I] where E is the total plastic strain, f is the function that depends on the stress, ? = f e -- dt, t is the duration of test, e is the base of natural logarithms, AH is the activation energy for creep, R is the gas constant,T is the absolute temperature, and s is the stress. Thus, identical values of are achieved during creep under a given stress at two alternate temperatures at the same total strain. At the same strain therefore where subscripts refer to the two alternate temperature conditions of test. Consequently, the activation energy for high temperature creep is readily obtained with the aid of Eq. 2. Activation energies so obtained have been observed to be insensitive to the creep strain at which they are evaluated, the applied stress, grain size, minor alloying additions,'-' cold worked state, and the presence of thermally stable dispersions of intermetallic compounds in an a solid solution matrix Furthermore, the activation energy for high temperature creep is very nearly equal to that for self-diffusion in all cases where adequate data are available for comparison." " The apparent identity of the activation energies for high temperature creep and self-diffusion strongly suggest that high temperature creep arises from a dislocation climb process. This hypothesis is further strengthened by the fact that the energy of activation for high temperature creep is insensitive to the applied stress," and by the observations that the correlation suggested by Eq. 1 cannot be ex- tended to temperatures below those for rapid crystal recovery. When using the activation energy for self-diffusion, Eq. 1 fails to give the required correlations between creep curves at various intermediate temperatures.' This suggests that the dislocation climb mechanism for creep might be superseded by some alternate mechanism in the intermediate range of temperatures. This investigation was initiated in a preliminary attempt to ascertain the type of creep law that might be valid in the intermediate range of temperatures. Special consideration, however, was given to the determination of the activation energy for creep in this range because the Becker-Orowan', " and the Mott-Nabarro10 theories for transient creep suggest that the activation energy should increase

Jan 1, 1957

By Ralph W. M. Lai, D. W. Fuerstenau

This paper presents the results of a study of the principles which control the distribution of ultrafine particles between an oil phase and an aqueous phase. Alkyl sulfonates were used to control the wettability of fine alumina particles and to stabilize the water-isooctane emulsion system in the extraction process. The effects of sulfonate chain length, sulfonate adsorption, pH, and oil-water ratio on the recovery of solids in the oil phase were investigated. Higher extraction was found under conditions which yield higher hydrophobicity and large interfacial area of the oil-water emulsion. Today there is considerable interest in developing methods for the recovery of fine particles from disseminated ores. One such method might be the extraction of fine particulate solids from aqueous suspensions into an oil phase, and one example of a successful industrial process based on oil-water distribution phenomena is the emulsion flotation process used in concentrating manganese ore.' The oil agglomeration process of Farnand, Smith, and Puddington has been suggested for concentrating tin ore. Patents 3-4 for oil flotation processes extend back to that of William Haynes in 1860. The basis of all these processes is directly related to the stabilization of emulsions with solid particles. The first extensive study of oil-water emulsions stabilized by finely divided solids was made by Pickering. Later, Briggs,6 weston, 7 Chessman and King,8 and Leja and Schulman9 experimentally demonstrated how solid particles control water-oil and oil-water systems. Hildebrand10 suggested that fine particles can stabilize an emulsion because the fine particles are partially wettable by both oil and water, that is, that the contact angle must be finite. Takakuwa and Takamori 11 recently applied emulsion inversion to the study of collector adsorption in flotation systems. At the Royal School of Mines, Shergold and Mellgren12 are currently carrying out a comprehensive study of the extraction of fine particles into an organic liquid phase. In the present study of the liquid extraction or oil flotation of ultrafine particles, the recovery of hydro-philic alumina particles of 0.1-µ average diameter was determined after separating an isooctane-water mixture (emulsion) into its two phases. Alkyl sulfonates of different chain lengths were used to change the wettability of the alumina and to effect emulsifi-cation of the oil-water mixture. The effects of the oil-water volume ratio, sulfonate adsorption, and pH on the recovery of the fine particles were investigated. Since the surface charge on an oxide such as alumina is determined by the adsorption or interaction of H+ and OH- with the surface, pH control is extremely important. Furthermore, since the zero point of charge (zpc) of alumina13-14 occurs at pH 9 to 9.4, major adsorption effects with anionic collectors in these systems will occur below pH 9. The results of the foregoing investigation are discussed in terms of the recovery of the fine particles, the oil-water ratio, contact angles, surface tension, the adsorption of sulfonate onto the solid surface, and the emulsifica-tion of oil. MATERIALS AND EXPERIMENTAL METHODS Materials: The particulate solid used in all the experiments was Linde "A" alumina, a high-purity, readily available form of a-alumina. The surface area of the alumina, as evaluated from measurements of stearic acid adsorption from benzene, was 14.5 sq m per gm, based on a value of 20.5 sq Å for the cross-sectional area of stearic acid.13 All aqueous solutions were prepared from triply distilled conductivity water. Other materials included high-purity crystals of sodium alkyl sulfonates, isooctane, and, for pH adjustments, reagent grade hydrochloric acid and sodium hydroxide-Because sulfonic acids are strong acids, they are

Jan 1, 1969

OFFICERS AND DIRECTORS (The Officers are the President, 6 Vice-Presidents, the Treasurer, and the Secretary) President and Director CARL E REISTLE, JR, '58 Past President and Director HENRY DEWITT SMITH, '57 President-elect and Director GROVER J HOLT, '59

Jan 1, 1956

United Engineering Society ARTHUR S. DWIGHT KARL EILERS J V N DORR Engineering Societies Library Board SYDNEY H. BALL JOSEPH E POGUE GEORGE C STONE JOHN H. JANEWAY Engineering Foundation Board J. V N. DORR JOHN M CALLOW GALEN H CLEVENGER

Jan 1, 1923

By W. H. Andrews

THE constantly increasing consumption of Portland cement in the State makes the above subject of partlcular interest at this time. The increasing demand is due to the rapid settling of the country and the fact that new uses are being found frequently for the above named commercial article. The industry is one that is bound to grow as the population increases, and this being the case, it may be well ,it this time to consider briefly- the matter of the chemical and physical com-position of proper raw materials. A cement mixture is one that contains approximately 75 per cent. carbonate of lime, 15 per cent. Silica, and 5 to 7 per cent. alumina, and iron oxides; the other elements being magnesium carbonate and small quantities of the rarer elements general associated with limestone deposits. It call be readily seen from the above composition that it is possible to build up this mixture from a number of different materials. First.-A rock high in carbonate of lime can be mixed with clay or shale in such proportions as to bring about the desired composition ; the chief difficulty in the building up of such a mixture is that it is hard to find a clay or shale in which the silica-alumina, ratio lies .between 4 to 1 and 3 to 1 and at the same time shows physical characteristics which will make certain its adaptability to the practical manufacture of Portland cement. Very often clays or shales are found which are right chemically but contain large quantities of grit or free silica. Such clays or shale must be ground to extreme fineness in the mixture in order to make the silica and alumina combine with the lime when the mixture is burned. On the other hand, clays or shales are often found that have the proper physical characteristics but in which the amount of alumina, is too great.

Jan 9, 1913

Executive.. CHARLES F. RAND, Chairman. JAMES F. KEMP, JOSEPH W. RICHARDS. ALBERT R. LEDOUX, BENJAMIN B. THAYER. Membership. BENJAMIN B. THAYER, Chairman. WALTER R. INGALLS, JOHN H. JANEWAY, Jr., JOHN D. IRVING, HERMAN A. PROSSER. Finance. EDWARD L, YOUNG, Chairman. KARL EILERS, JAMES GAYLEY. Library. JAMES F. KEMP, Chairman. JOHN HAYS HAMMOND,3 E. GYBBON SPILSBURY,2 ALES. C. HUMPHREYS 4 BRADLEY STOUGHTON.

Jan 7, 1913

V. H. GOTTSCHALK, Rolla, Mo. (written discussion*).-In connection with Mr. Waring's quotation of Urbain's work, attention may be drawn to a remark found in the report of the session of the Société de Chimie Physique,1 held in December, 1909, that, while all blendes contain gallium in larger or smaller quantities, those blendes carrying indium are generally free from germanium, and vice versa. Urbain, furthermore, . expresses his conviction that this behavior, being related to the condi-tions of deposition of the ore, should be an important factor in determining the origin and mode of formation of zinc blende deposits., In. searching the literature for the naturally expected sequel to these remarks, there is found a report on the extraction of germanium from blende, after many months' work, on a commercial scale;2 then a paper3 on some Spanish blendes, all containing cadmium, examined by Urbain's 'method (this paper contains, also, very important work on the com-position and color of blendes, as well as on the occurrence of organic .matter and of inclusions in such blendes), and a second paper on Spanish blendes in general, in which this original point of Urbain's concerning the relative quantities of the three rare elements is taken up.4 Angel del Campo finds that of 68 specimens examined, four only were entirely free of germanium, gallium, and indium;. 38 had small proportions, while 19 were notably, and seven relatively rich in the three rare metals. He found the relative frequency to be: gallium in 60, germanium in, 50, and indium in 38; all three occurred in 29 cases; germanium and gallium together in 18; gallium and indium together in four; germanium and indium together without gallium, in none; four had gallium only, three had germanium only, and one had indium only; in 23 it appeared feasible to extract these elements. Finally, it may be worth mentioning that the discovery of gallium in commercial aluminum5 brought forth two

Jan 1, 1918

By Keith Leonard Sutherland, Ian William Wark

Mercaptobenzthiazole and its sodium salt are marketed under the trade names Flotagen and Flotagen S respectively, for use as collectors for cerussite and other minerals. The structural formulas for sodium rnercaptobenzthiazole and for sodium ethyl xanthate are: Chemically there is a resemblance between the two compounds, though the free acid (mercaptobenzthiazole itself) is much more stable than xanthic acid. Both are readily oxidized, e.g., by iodine to disulphides, and can be estimated by iodometric titration. Qualitatively they are similar as collectors in flotation, although there are quantitative differences between them that may be important in practice. It is deduced that the influence of the nitrogen atom is subordinated to that of the sulphur atoms, and that the dominant group of these compounds is the mercapto group —SH or —5Na. The general method of investigation has been based on contact tests. Two temperatures, 10" and 35" C., have been chosen, and with a standard concentration of 20 mg. per liter of mercaptobenzthiazole (i.e., of the free acid) the influence of alkali, cyanide and copper sulphate on contact at sulphide mineral surfaces has been studied. This standard concentration corresponds to about 19 mg. per liter potassium ethyl xanthate; it brings out the differences between the minerals better than a higher concentra-

Jan 1, 1939

By Ian William Wark, Keith Leonard Sutherland

MERCAPTOBENZTHIAZOLE and its sodium salt are marketed under the trade names Flotagen and Flotagen S respectively, for use as collectors for cerussite and other minerals. The structural formulas for sodium mercaptobenzthiazole and for sodium ethyl xanthate are: [ ] Chemically there is a resemblance between the two compounds, though the free acid (mercaptobenzthiazole itself) is much more stable than xanthic acid. Both are readily oxidized, e.g., by iodine to disulphides, and can be estimated by iodometric titration. Qualitatively they are similar as collectors in flotation, although there are quantitative differences between them that may be important in practice. It is deduced that the influence of the nitrogen atom is subordinated to that of the sulphur atoms, and that the dominant group of these compounds is the mercapto group -SH or -SNa. The general method of investigation has been based on contact tests. Two temperatures, 10º and 35º C., have been chosen, and with a standard concentration of 20 mg. per liter of mercaptobenzthiazole (i.e., of the free acid) the influence of alkali, cyanide and copper sulphate on contact at sulphide mineral surfaces has been studied. This standard concentration corresponds to about 19 mg. per liter potassium ethyl xanthate; it brings out the differences between the minerals better than a higher concentra-

Jan 1, 1939

By Ian William Wark, Keith Leonard Sutherland

Mercaptobenzthiazole and its sodium salt are marketed under the trade names Flotagen and Flotagen S respectively, for use as collectors for cerussite and other minerals. The structural formulas for sodium rnercaptobenzthiazole and for sodium ethyl xanthate are: Chemically there is a resemblance between the two compounds, though the free acid (mercaptobenzthiazole itself) is much more stable than xanthic acid. Both are readily oxidized, e.g., by iodine to disulphides, and can be estimated by iodometric titration. Qualitatively they are similar as collectors in flotation, although there are quantitative differences between them that may be important in practice. It is deduced that the influence of the nitrogen atom is subordinated to that of the sulphur atoms, and that the dominant group of these compounds is the mercapto group —SH or —5Na. The general method of investigation has been based on contact tests. Two temperatures, 10" and 35" C., have been chosen, and with a standard concentration of 20 mg. per liter of mercaptobenzthiazole (i.e., of the free acid) the influence of alkali, cyanide and copper sulphate on contact at sulphide mineral surfaces has been studied. This standard concentration corresponds to about 19 mg. per liter potassium ethyl xanthate; it brings out the differences between the minerals better than a higher concentra-

Jan 1, 1939

By Ian Wark

MERCAPTOBENZTHIAZOLE and its sodium salt are marketed under the trade names Flotagen and Flotagen S respectively, for use as collectors for cerussite and other minerals. The structural formulas for sodium mercaptobenzthiazole and for sodium ethyl xanthate are: Chemically there is a resemblance between the two compounds, though the free acid (mercaptobenzthiazole itself) is much more stable than xanthic acid. Both are readily oxidized, e.g., by iodine to disulphides, and can be estimated by iodometric titration. Qualitatively they are similar as collectors in flotation, although there are quantitative differences between them that may be important in practice. It is deduced that the influence of the nitrogen atom is subordinated to that of the sulphur atoms, and that the dominant group of these compounds is the mercapto group -SH or -SNa. The general method of investigation has been based on contact tests. Two temperatures, 10° and 35° C., have been chosen, and with a standard concentration of 20 mg. per liter of mercaptobenzthiazole (i.e., of the free acid) the influence of alkali, cyanide and copper sulphate on contact at sulphide mineral surfaces has been studied. This standard concentration corresponds to about 19 mg. per liter potassium ethyl xanthate; it brings out the differences between the minerals better than a higher concentra-

Jan 1, 1939

By Charles Clayton

A study of the literature shows that the greater part of research work on annealing of cold-worked iron has been for the purpose of studying the effect on grain-size and properties other than hardness. No reference has been found of experimental work of the same nature as that explained in this short paper. The material used throughout was Vismera iron, an iron containing 0.03 carbon and made several years ago by the Inland Steel Co. One-half inch stock was cut into cylinders ¾ in. long. The cylinders were then compressed for 60 sec. in a Reihle testing machine under loads as indicated below: COMPRESSION, AVERAGE LENGTH, SERIES POUNDS INCHES 1 10,000 0.693 2 15,000 .599 3 20,000 .501 4 25,000 .426 5 30,000 .378 6 35,000 .351 7 40,000 .311 Fig. 1 shows these cylinders after compression. Each series con¬sisted of 17 specimens lettered 0, B, C, D, E, E:, G, H, I, J, K, L, M, N, P, Q, and R. One specimen of each series was reserved for study of the properties in the cold-worked condition. The other specimens were annealed in a Hump furnace for ½ hr. at the following temperatures:

Jan 2, 1926

(Members are urged to send in for this column any notes of interest concerning themselves or their fellow-members.) Members and guests who called at Institute headquarters during the period Jan. 10, 1916 to Feb. 10, 1916: William Rettie, Yonkers, N. Y. Wallace E. Pratt, Manila, P. I. R. V. Norris, Wilkesbarre, Pa. T. Skewes Saunders, El Oro, Mex. Fred MacCoy, El Oro, Mex. M. L. Requa, San Francisco, Cal. Reno H. Sales, Butte, Mont. R. W. Schultz, Ravenna, O. R. T. White, Batourn, Russia. H. J. Brown, Chester, Pa. David T. Day, Washington, D: C. A. M. Van Rensselaer, New Rochelle, N. Y. H. M. LaFollette, LaFollette, Tenn. Norman C. Stines, Russia. F. N. Speller, Pittsburgh, Pa. Howard R. Hughes, Houston, Tex. Robert W. Hunt, Chicago, Ill. C. F. Schnepp, Ridgefield Park, N. J. B. E. Fernow, Toronto, Ont., Can. George L. A. Thomson, Elizabeth, N. J. A. F. Bennett, New York City. Jasper T. Robertson, Chicago, Ill. J. C. Ralston, Spokane, Wash. J. B. Tyrrell, Toronto, Ont., Can. George J. Lyon, Schenectady, N. Y. H. G. Officer, New York Cty. Jesse C. Porter is now superintendent of the San Fernando Mine, Hoyo de Manicaragua, Santa Clara Province, Cuba.

Jan 3, 1916

A. E. Hunt, Pittsburgh, Pa : I have heard these papers read with a great deal of pleasure. I am particularly interested, in a financial way, in the bauxites as ores of aluminum, and it is safe to prophesy that there will be many more mining engineers in the future who will be interested in these ores of aluminum, in the same way as many are

Jan 1, 1895

By Samuel Taylor

IT is customary for the president of an engineering society, in his annual address, to describe either some engineering problem with which he has beer connected or to review the work of the society during his administration. My first thought, this being the sesquicentennial year of our nation, was to review the advance in coal mining for the past fifty years, during which period I have been more or less intimately con-nected with the bituminous coal industry, and have personally witnessed most of the great changes which have occurred in methods and machinery used in the production of coal, but preparation of the requisite address would take more time than could be spared to prepare it, and its presentation would consume so much time that it .would not be suitable. The new arrangement providing for giving the presi-dent's address at the business meeting makes it more .appropriate to review the work of the Institute during the past year, together with some suggestions which appeal to me as being of advantage to the future wel-fare of the Institute, which I will try to do briefly. The work of the business office has been reviewed in the Secretary's report and it will not be necessary for me to dwell on it. Suffice it to say, it seems to be going along very well. Additional work could be done which would be to the advantage of the Institute, if we had the money with which to defray the necessary ex-pense incident to it, but I will refer to this again later. I would be derelict if I did not refer to the splendid work of the Secretary and the Assistant Secretary. Keeping in touch with all the sections, which number now about 26, and affiliated student societies which number 40, besides special committees, and represent-ing the Institute on various boards, provides work enough to occupy the Secretary's time almost exclu-sively. In addition to this the Secretary and the As-sistant Secretary have the work of editing and publishing the TRANSACTIONS of the Institute; the issuing of the magazine, MINING AND METALLURGY, in the splendid manner in which it goes out to the mem-bership is no light task and I think they should receive the commendation of the membership for this work.

Jan 3, 1927

By Thomas Fraser, David R. Mitchell

THE primary purpose of the loading plant is to transfer the finished product from the preparation machines to the railroad car, truck, or barge in which it is to go to market. Secondary purposes of the loading plant are: to prevent excessive degradation of sizes during loading, to reduce segregation as much as possible, and to prevent excessive quantities of very good or off-grade coal from entering any one car. Nonuniformity of consignments is one of the chief sources of com- plaints by consumers and coal merchants. A properly designed loading plant will do much to reduce complaints and ensure uniformity, not only from shipment to shipment but also in each individual consignment along the length of the car and in cross section. DEGRADATION IN STORAGE, LOADING AND SHIPMENT The object in loading is not only to handle the coal without breakage and segregation, but also to produce a well-trimmed load that will ride to its destination without spillage or breakage en route. The small sizes present in a car of prepared coal as received by the purchaser consist of: missed small sizes not screened out in the preparation plant, breakage during loading, and breakage caused by handling en route. For domestic sizes of anthracite shipped from the Pennsylvania anthracite field to Atlantic coast cities, the dealers' loss because of break- age in loading and shipment amounts to from 2 to 5 per cent and for anthracite shipped to Middle West cities, the loss is 8 to 9 per cent. This difference is in part because dealers in the Middle West rescreen their coal more thoroughly than is usual in the East. One dealer handling Illinois No. 6 coal shipped from southern Illinois mines to Chicago reports an average size loss of 10 per cent when lump coal is unloaded with a fork. This runs as low as 5 per cent for carefully loaded coal and as high as 15 per cent for carelessly loaded coal.

Jan 1, 1943

By Harrison R. Cooper

With problems of diminishing ore grades and increasing cost of facilities, the mineral industry is acutely aware of the needs for improving beneficiation processes. Industry and universities are directing intensive technical effort to develop- ment of techniques with potential for using digital computers in automation and process analysis. The main problem of early attempts at on-line computer process control methods was that of economics. Now, with new advances in analysis and modeling making practical application economically important, it appears that minerals beneficiation is on the threshold of a significant jump in operating technology. In reviewing this work, particular note was taken of research and development applied to fundamental processes and the significant areas of effort where operations research techniques are used for process applications leading to the current state-of-the-art. Development of data automation and on-line control methods for process industries is deferred to the next section of this volume. This section deals with computer-facilitated mathematical-modeling development and reviews this work in conjunction with associated prior fundamental research leading to development of the methods. Flotation The 1960 state-of -the -art in flotation modeling was com- piled by Arbiter and Harris in the volume, 50th Anniversary of Froth Flotation, edited by Fuerstenau1. Many workers in the field of flotation initiated their research through flotation models, and this effort has led to use of simulation and operations re search methods employing computer techniques to facilitate advance of this work. The flotation model of Imaizumi and Inoue, published with supporting data in 1962, was expanded in 1968 with the objective of developing a basis for process automation.2,3 The fundamental work of Woodburn and Loveday in 1965 has led to techniques applicable to flotation circuit design optimization.4 This analysis is described in this volume by Woodburn in conjunction with King, Buchalter, and Piper. Niemi5,6 derived models for dynamics of a flotation circuit which were employed in developing a model describing

Jan 1, 1969

By J. B. Umpleby

PRoduction engineering in 1927 may be characterized by a great. clarification of fundamental conceptions, and many improvements in technique. During the year the profession has received tnarked recogni-tion by the industry and to an extent never before attained has become an integral part of it. History Petroleum production engineering is a new profession. Prior to 1925, when this Institute undertook the work, no forum existed for the open discussion of its technical problems. There was no attempt at a handbook of the subject prior to "Petroleum Production Methods by J. R. Suman, in 1921, and no textbook prior to Petroleum Production Engineering" by L. C. Uren, in 1924. As late as 1926, only six schools and universities offered special courses in petroleum production engineering. Prior to about 1923, engineers engaged by oil companies were used almost exclusively for construction and location work. Two of the leading production engineers in the Mid-Continent field, although with their respective companies more than twelve years, were not definitely assigned to production work until 1924. Both men now head large departments giving almost their entire time to production problems. Because of the newness of the profession, the leading production engineers of today have had their fundamental training in mining, civil, mechanical and electrical courses. Not unlikely this diversified training is in considerable part responsible for the amazing growth of the profession. I believe, however, that recognition is due principally to economic pressure within the industry which has directed attention more and more sharply on costs and efficiency. After all, the justification for the growth and continued development, of the profession is to recover more oil from a given unit of sand at less cost per barrel. In this new profession, it seems to me that greatest progress will result from focusing thought and effort on this single objective, and if I might offer one suggestion to the com-

Jan 1, 1928

By R. W. Bond

The gas-lift is a comparatively recent development in the Oklahoma and Kansas fields. It was used to some extent in the old Dilworth field several years ago, but the first extensive installations were made in the Tonkawa and Garber fields in Oklahoma early in the year 1926. Compressor Equipment During the early development of the system, the equipment used generally consisted of small tandem compressors of about 250 cu. ft. per min. displacement, driven by automotive-type gas engines, using a short belt drive. These compressors were first installed at the individual wells largely as an experiment. After the experimental installations had proved the method a success, it was considered economically advisable to centralize the compressor equipment in strategically located stations. However, as the information in regard to "gas-lift flowing life" was anything but definite, and the most optimistic estimates in regard to it did not exceed six months, portability of equipment was still the first consideration in the minds of many operators, who continued to install srnall semi-portable com-pressors in their centralized stations. As electric power became available in the fields, the electric motor came rapidly into use as the prime mover for the small compressors. The operating cost of this motor is greater than that of the automotive-type gas engine for the same power output, but the greater continuity of service tends to balance the extra cost. Aside from the semi-portable units, a number of strictly portable compressors were used. These consisted of automotive-type gas engines direct connected to vertical compressors. The unit was assembled on one base and could be mounted on wheels or skids as desired. The chief objection to these, in the writer's opinion, was their small capacity— approximately 150 cu, ft. per min.—which made it necessary to use two, three, and sometimes more units per well, thus making the installation rather costly. However, they have been found valuable for test purposes and emergencies, where installation time is an important factor.

Jan 1, 1928