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By C. Crussard, R. Tamhankar

It is the policy of The Metallurgical Society to provide, in the TRANSACTIONS OF THE METALLURGICAL SOCIETY OF AIME, a prompt and accurate medium for publication of reports of significant new research in both the scientific and engineering aspects of metallurgy. Papers submitted to the Society are judged by competent reviewers accord-ing to established criteria for technical merit, accuracy, originality, and presentation. STAFF: Editor, Gerhurd Derge Carnegie Institute of Technology Schenley Park Pittsburgh 13, Pa. Editorial Assistant, M. A. Redmerski Staff Coordinator, James J. Burke THE METALLURGICAL SOCIETY: W. R. Hibbard, Jr., President; J. C. Kinnear, Jr., Past-President; John Chiprnan, Vice President; T. D. Jones, Treasurer; R. W. Shearman, Secretary. PUBLICATIONS COMMITTEE OF THE METALLURGICAL SOCIETY: A. W. Thornton, Chairman; Dennis Carney, John Chip-man, J. C. Fulton, J. H. Hollomon, H. H. Kellogg, A. E. Lee, R. Maddin, J. D. Sullivan, and D. Swan. Review and selection of manuscripts is under the supervision of the following Publications Committees: Extractive Metallurgy Division: T. B. King, Chairman; S. J. Dickenson, R. P. Hermsdorf, R. Schuhmann, Jr., and P. T. Stroup. Institute of Metals Division: Robert Maddin, Chairman, F. Lincoln Vogel, Jr., Vice-chairman, W. A. Backofen, R. W. Balluffi, J. H. Bechtold, M. B. Bever, R. S. Busk, C. G. Goetzel, Paul Gordon, C. D. Graham, .Jr., Robert F. Hehemonn, R. I. Jaffee, F. E. Jaumot, Jr., Irving R. Kramer, A. J. Lena, Harold Margolin, C. J. McHorgue, Russell A. Meussner, J. B. Newkirk, H. W. Paxton, G. E. Pellissier, I. S. Servi, Alan U. Seybolt, A. J. Shaler, and Jack Washburn. Iron and Steel Division: J. C. Fulton, Chairman; T. B. King, F. C. Langenberg, W. 0. Philbrook, and T. 0. Winkler. Published bimonthly by the American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc., 29 West 39th Street, New York 18, N. Y. Telephone: PEnnsylvania 6-9220. Subscription $20 per year for non-AIME members in United States and North, South, and Central America; $25, foreign; $5 for AIME members. Single copies, $4.00, single copies foreign, $5.00. The AIME is not responsible for any statement made or opinion expressed in its publications . . . Copyright 1958 by the American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc. . . . Registered cable address, AIME New York ... Indexed in Engineering Index, Industrial Arts Index, and Chemical Abstracts... Second class postage paid at New Yark, N. Y., and Ann Arbor, Mich. Volume 212, Number 6.

Jan 1, 1959

By Harry T. Hamilton

THE genial assistant to the president of the New York Trust Co. is the latest addition to the Institute's board of directors, having been elected at the March meeting of the hoard to fill the unexpired term of the late E. E. Ellis. Usually when a banker is appointed to the board of a company the reason is obvious; the difference in this case is that the New York Trust Co. has some of the Institute's money, instead of vice versa. But Harry Hamilton is not really a banker-at least not primarily. Frefluently big financial institutions have a good mining engineer on their staffs to keep them from financing too many "cats and dogs." At any rate Mr. Hamilton gave up his consulting practice in San Francisco back in 1927, to accept his present position in New York. Until then, from the time he graduated from Yale in 1904, lie was constantly engaged in mining operations of one kind or another in the West and in Mexico. His first job was at Christmas, Ariz., where lie did "sampling and miscellaneous work" for the Saddle Mountain Mining Co. The writer tramped up to, all over, and through that property one hog day many years later, when it was run by the Christmas Mining Co., and carp assure the reader that without doubt the young Yale graduate got some good experience and was well broken in. From there Mr. Hamilton went to Cananea for a time, and then to the Copper Queen, at Bisbee, where he was a valued member of the rigging gang. An assignment of assaying and sampling for the Shan¬non Copper Co. at Metcalf lasted for a few months and then he accepted a job for a year with the geological department

Jan 1, 1936

THERE are three objectives in translation of works of this character : to give a faithful, literal translation of the author's statements ; to give these in a manner which will interest the reader ; and to preserve, so far as is possible, the style of the original text. The task has been doubly difficult in this work because, in using Latin, the author availed himself of a medium which had ceased to expand a thousand years before his subject had in many particulars come into being ; in consequence he was in difficulties with a large number of ideas for which there were no corresponding words in the vocabulary at his command, and instead of adopting into the text his native German terms, he coined several hundred Latin expressions to answer his needs. It is upon this rock that most former attempts at translation have been wrecked. Except for a very small number, we believe we have been able to discover the intended meaning of such expressions from a study of the context, assisted by a very incomplete glossary prepared by the author himself, and by an exhaustive investigation into the literature of these subjects during the sixteenth and seventeenth centuries. That discovery in this particular has been only gradual and obtained after much labour, may be indicated by the fact that the entire text has been re-typewritten three times since the original, and some parts more often ; and further, that the printer's proof has been thrice revised. We have found some English equivalent, more or less satisfactory, for practically all such terms, except those of weights, the varieties of veins, and a few minerals. In the matter of weights we have introduced the original Latin, because it is impossible to give true equivalents and avoid the fractions of reduction ; and further, as explained in the Appendix on Weights it is impossible to say in many cases what scale the Author had in mind. The English nomenclature to be adopted has given great difficulty, for various reasons ; among them, that many methods and processes described have never been practised in English-speaking mining communities, and so had no representatives in our vocabulary, and we considered the introduction of German terms undesirable ; other methods and processes have become obsolete and their descriptive terms with them, yet we wished to avoid the introduction of obsolete or unusual English ; but of the greatest importance of all has been the necessity to avoid rigorously such modern technical terms as would imply a greater scientific understanding than the period possessed. Agricola's Latin, while mostly free from mediaeval corruption, is somewhat tainted with German construction. Moreover some portions have not

Jan 1, 1950

By L. F. Elkins

Water coming into wells with bottom water present in the Fosterton field, when their oil recovery was only 0.1 to 1.5 per cent of oil in place below the lowest perforation, confirms lack of shale barriers to vertical flow which also are not apparent in cores and electric logy. Low contrast of vertical and horizontal permeability, high mobility ratio betweerz oil and water zone and pos.rible rate effects due to gravity Combine to prevent easy analysis of water invasion pattern and efficiency by analogy or intuition. Theoretical analysis of performance including these factors using a new direct nurnerical .solution of potential distribution in a network led to unanticapted indications that water would under-run the entire oil reservoir with low volumetric coverage if supplied through natural influx or peripheral water injecfion below the oil-water contact. An unusual pattern of water injection is to he adopted in this recently unitized pool to provide more uniform water flooding in that two-thirds of the oil reservoir not underlain by bottom wafer. INTRODUCTION The Fosterton field, Southwestern Saskatchewan, Canada, was discovered in Jan., 1952. It produces at a depth of 3,100 ft from a pinch-out of the Roseray sand at the Lower Cretaceous-Jurassic unconformity. The field, covering 2,500 acres, contains 54 wells on 40-acre spacing. Development was essentially complete in June, 1954, but significant production did not start until May, 1955, when a pipeline outlet became available. Within one year rapid in- creases in gas-oil ratio and early encroachment of water created operating problems in the down-structure eastern half of the field and raised serious questions about reservoir performance and ultimate recovery. This paper describes the unusual behavior of water encroachment—on both well and reservoir bases—and the analyses made to interpret it. The field was unitized July 1, 1958, for water flooding. A somewhat unconventional

By W. R. Hibbard

Evidence is presented which confirms previous findings that models of solution strengthening depending solely on lattice parameter changes are incomplete. Direct evidence for the Suzuki interaction of chemical effects was obtained from alloys with constant lattice parameter, for which solution strengthening was nearly independent of temperature from 300° to 20°K. SOLUTION hardening principles have been reviewed recently by Parker and Hazlett.' In addition, the interactions of dislocations and solute atoms were reviewed by Cottrell.' It is not proposed to review this information again here, but to refer only to those details which are pertinent to the developments which have occurred since these papers were published. Literature Survey To set the stage, it has been known for some time that solid solutions are stronger than the pure parent metals, and that the strength increases with increasing amounts of alloying element. One of the most extensive earlier investigations was that of Lacy and Gensamer,3 who reported that the solid solution strengthening of iron is a power function of the composition, that the relative strengthening is a function of the solubility limit, and that the rate of strain hardening is a function of the amount of solution hardening. Thus, the slope of the plastic portion of the stress-strain curve increases with increasing yield strength. An approach to the development of principles resulted from work by Gulyeav,4 who reported that the strengthening effect of solid solution alloys is periodic in character when plotted as a function of the atomic number of the solute. A more quantitative approach was to relate the amount of solution hardening to the lattice parameter of a solid solution. This was done quite early by Norbury,5 and later by Brick, Martin, and Angier,6 Frye and Hume-Rothery,7 and French and Hibbard. This relationship is only approximate in character. The next development was to relate the amount of solution hardening to lattice stress, as proposed by Frye and co-workers.9 They calculated what they called ionic overlap from the lattice parameter changes represented as a change in volume, using Bridgman's hydrostatic compression equation. The resulting correlation was somewhat improved as compared to the simple correlation with lattice parameter. The next step was carried out by Dorn, Pietrow-sky, and Tietz,10 who suggested an effect of valence differences in addition to the effect of lattice parameter. Their proposed parameter shows flow stress as a single valued function of the concentration and a relationship involving these two atomic variables. In addition, they contributed new data on the temperature dependence of solution hardening which indicated that it was a strong function of temperature for aluminum alloys. Allen, Schofield, and Tate11 carried the valency effect even further by reporting data indicating that with a given solvent element the stress-strain curve is a function of electron density, entirely neglecting the size factor, which varied by a factor of two. This evidence led to a quantum mechanical calculation by Cottrell, Hunter, and Nabarro,12 based on the formation of a dipole around an edge disloca-

Jan 1, 1959

By Linney, Robert J.

REPUBLIC Steel Corporation's iron-ore properties in the Adirondacks consist of mines, mills, and sintering plants in the Mineville and Port Henry area and at Lyon Mountain. This article will deal with the properties in the vicinity of Mineville and Port Henry. In 1938, when Republic leased the Mineville- Port Henry operations from the Witherbee Sherman Corp., these properties had just come through some hard depression years. As a result, the mine development program was far behind schedule; most of the equipment needed replacement; and above all, the entire system of mining had to be completely changed to reduce operating costs. The concentrator had been in operation for many years; the process was dry and dusty. Machinery and equipment were either badly worn or entirely obsolete. The sintering plant, also long in operation, was badly in need of repairs.

Jan 1, 1943

By Maxwell Gensamer

Jan 1, 1960

By R. E. Morgan, D. L. Douglass

The determination of phase relationships and solid-solubility limits can be performed by quantitative metallography in addition to the usual X-ray and metallographic techniques. For example, Beck and smith1 redetermined the ß/ß + ?, ß + ?/?, a/a + ß and a + ß/ß boundaries in the Cu-Zn system by measuring the volume fraction of second phase of several alloys and extrapolating the volume fraction-composition curves to 0 and 100 pct. A modification of this technique is suggested for certain alloy systems, in which it is not necessary to use several alloy compositions but merely one. A single two-phase alloy may be used to determine terminal solubilities in the following manner. The method consists of equilibrating samples of the alloy in a two-phase region adjacent to the desired solid solution, at three or more temperatures, quenching, measuring the volume fraction of second phase present, and applying an analytical treatment to calculate the unknown solid solution. However, two restrictions are inherent in this technique. They are: 1) only certain types of alloy systems are amenable to it, and 2) the general features of the system must be known. The first drawback to the new technique, i.e., that only certain types of systems may be studied, necessitates that the composition at one end of the tieline must either be constant with temperature or well established as a function of temperature. Either a pure metal or some intermetallic compounds fulfill the former. If it is assumed that the volume per gram-atom of a dilute solution is unchanged by the addition of element B to element A, the composition of the solid solution in equilibrium with the second phase may be determined by a material balance and is given by where X, = volume fraction of B in a solid solution Xc = volume fraction of B in compound c X = volume fraction of B in alloy f = volume fraction of second phase The composition by weight may then be determined by the use of tables in the Metals Handbook2 when the density ratio of the solid solution constituents is known. A possible alternative treatment involving the use of the lever rule is less precise than the above tech- nique. This may be used when the density of the solid solution is either known or may be calculated from X-ray data for several compositions. The following analysis is then made. The ratio of compound to solid solution (by weight) may be expressed as follows: x0 - x wc = xr-x = x0 - x r2i Xc -X where Wc = weight of compound w = weight of solid solution x, - alloy composition, weight percent x = unknown composition Xe = compound composition but where V, = volume of compound VA = volume of solid solution pc = density of compound p, = density of solid solution fc = volume fraction of compound fB = volume fraction of solid solution and fs = l -fc then If pc and xc are known, and f, is measured, then pB is the only unknown on the right side of Eq. [4]. The known densities of the solid solution can be plotted for various compositions and can then be expressed mathematically as a function of composition. The use of an expression of pB = f(x)reduces the equation to one unknown—the desired solubility. In the event that the densities are unknown, they may be calculated for various compositions from Vegard&apos;s law. The calculated values are then plotted and expressed analytically. The most accurate results are obtained for Eq. [4] when fc<< 1, i.c., when (x, -x,) - 0, &/l-f, - m; but as fc/l -fc - 0, (xl-x,)- (x, - x), and x - x,,. However, the accuracy with which fc can be measured decreases as f, decreases.3 Alloys for investigation must be selected by a compromise, which is based upon an error analysis of Eq. [4] and knowledge of the accuracy of volume fraction measurements. An examination of phase diagrams in the literature showed many which were amenable to the technique described here. The zirconium-copper system was selected in order to determine the solubility of copper in beta zirconium. Pieces of an alloy which was arc-melted three times were wrapped in tantalum foil and sealed under an argon atmosphere in Vycor tubes. The sealed samples were equilibrated at temperatures from 850" to 960°C for 3 weeks and quenched to room temperature by smashing the capsule in water. Several planes of polish were examined, and

Jan 1, 1960

By John Chipman, Wayne L. Worrell

Using recent thermodynamic data for the carbides and oxides of tantalum, columbium, and vanadium, the stable solid phases aboue 1300°K and at 1 atm CO(g) pressure in each M-C-O system have been determined. Pourbaix-Ellingham diagrams have been constructed and are used to estimate the minimum temperatures necessary to obtain these metals by carbothermic reduction under reduced pressures. TANTALUM, columbium, and vanadium react with carbon to form the M,C and MC carbide phases. The M,C carbides have narrow homogeneity ranges, but the MC phases possess considerable ranges of homogeneity.&apos; The free energies of formation of the MC carbides were recently measured, and those of MC and M2Ccarbides have been estimated., (The notations MC and MC denote, respectively, the carbide compositions at the carbon-rich and at the metal-rich boundaries of the homogeneous MC phase.) In this paper, these carbide data are combined with thermodynamic data for the oxides to predict the stable phases in the Ta-C-O, Cb-C-O, and V-C-O systems at specified temperatures and oxygen pressures. M-C-O PHASE DIAGRAMS The solid phases in equilibrium above 1300°K for each M-C-0 system are shown in Figs. 1, 2, and 3. Above 1300°K, the vapor would consist entirely of carbon monoxide; and these phase diagrams were obtained by specifying the vapor pressure of CO(g) to be 1 atm. The temperature at which any two solid phases become unstable is specified along the two-phase equilibrium lines in each diagram. To simplify the diagrams, all solid phases in the Ta-C-O and Cb-C-O systems are represented as stoichiometric compounds. However, the homogeneity ranges of VO and VC are indicated, because they form a complete series of solid solutions.3 It also should be noted that the homogeneity range of

Jan 1, 1964

In 1962, minerals beneficiation showed definite signs of coming out of the doldrums into which it has drifted after the uranium boom. Demand by steelmakers for high-grade iron pellets has created the need for concentrating plants to upgrade specular hematite by spiral concentration or flotation and magnetites by magnetic means and flotation. According to a paper given at the AMC annual meeting by C. S. Arms of Pickands Mather, "the shipment of pellets, started in the mid-1950&apos;s, has increased to 17.6 million tons in 1961 from North American operations. Many plants already underway will raise this production to about 42 million tons by 1965. This will be a very sizeable percentage of the total iron ore production contemplated by that date." Iron ore concentration methods are gradually raising the assay of pellets into the 65 to 69% Fe range and lowering silica to the 4 to 7% range. Quebec Cartier&apos;s Lac Jeannine concentrator went into operation in late 1961 and all grinding units were running by 1962. The Iron Ore Co. of Canada&apos;s new Carol Lake plant was started in mid-1962.

Jan 2, 1963

By Albert Sauveur

It is delightful to read a technical paper like that of J. E. Johnson, The Effect of High Carbon on the Quality of Charcoal-Iron, presented in October, 1912, at the Cleveland meeting of the American Institute of Mining Engineers.&apos; The clear, simple, and straightforward manner in which he describes his experiments and results makes you feel as if you had been, so to speak, at his elbow during the course of his investigations, while his method of procedure is so rational that you can fairly anticipate each step in the logical sequence of the tests performed. The following notes suggested by Mr. Johnson&apos;s paper are presented here in the hope that they may help, if only a mite, towards the final solution of a problem of considerable scientific and industrial importance. Physical Properties of Cast-Iron us. Its Ultimate Composition. Mr. Johnson writes that " an investigation along the lines of consumption showed that different irons have different characters totally independent of their analyses," and he declares that " the presence or absence of these elements [meaning carbon, phosphorus, silicon, and manganese] alone will not account for all, scarcely for a half, of the facts which have long been known." He further tells us that some foundries have " proved, by the most irrefutable tests, that they could take a certain iron of a given analysis and produce certain results," while with " another iron of the same analysis they could not produce these results at all." I feel confident that every experienced and thinking metallurgist will readily believe Mr. Johnson&apos;s statements and will share his views in regard to the hopelessness of inferring the

Jan 1, 1914

By Waldemar Lindgren

THE following pages present data accepted by many geochemists and geologists regarding the succession of minerals and the temperatures of formation in ore deposits affiliated with igneous rocks. They also present the individual views of the author on the composition of the solutions that were active and on the mode of deposition. He does not regard these views as speculations or hypotheses but as forming a well motivated and consistent theory. It is not certain, however, that all investigators will subscribe to them.

Jan 1, 1936

Jan 1, 1966

By M. E. Wadsworth, T. D. Chatwin

The kinetics of sulfidization of hematite (Fe203) by H2S gas at various partial pressures have been determined over the temperature range of 170° to 500°C. The process was controlled by thin films of pyrite (FeS2) and troilite (FeS) which were protective and formed diffusional layers. At higher temperatures the thermodynamic drive to form FeS2 decreased, and consequently the rate of formation of FeS, decreased. Conditions for the development of thin layers of FeSz consisting of 10 to 100 atomic diameters are presented. Laboratory flotation results on synethetic ores indicate floatability identical to that of pyrite of normal xanthate flotation. The prospect of high-temperature sulfidization of metal oxides using H2S, S, or other sulfur bearing compounds is intriguing as a potential activation process for flotation since the thermodynamics are very favorable for a large number of systems. If the kinetic parameters are sufficiently well understood it may be possible to provide surface sulfide layers a few angstroms thick, thus imparting normal sulfide floatability characteristics to the oxide. For thin layers the total sulfur pick-up would be small except for very high surface area materials but in most cases this sulfur could be readily removed by roasting if necessary. The general reactions for the sul-fidization of metal oxide MxO, to a metal sulfide MpSq using H2S may be written for the three conditions py > xq; py < xq; and py = xq: A large thermodynamic advantage is obtained in many systems because of the relatively large negative free energy of formation of H,O compared to H,S. For the temperature range 2S° to 1500°C &apos; where AFOis the standard free energy and T is absolute temperature. As is evident from Eqs. 4 and 5, the free energy of formation of H ,0 is approximately 35 to 37 kilocalories per mole greater than that for H,S over broad variations of temperature. For oxide-sulfide systems as outlined above, sulfidization may be expected to occur for the conditions: Groups I and 111: that is, if the terms on the right are more negative than those on the left the reaction is expected to occur thermodynamically. The value hFg,(,) is included in Eq. 6 since hFLzs is based upon gaseous S2 rather than the normal reference state, orthorhombic sulfur. The

Jan 1, 1969

By L. E. Fish, G. S. Wyman

CHUQUICAMATA open-pit mine is capable of producing a total of 105,000 tons daily. When the sulphide plant is operating to capacity the distribution of this quantity will be approximately 30,000 tons sulphide ore, 30,000 tons oxide ore and 45,000 tons of waste. At that time the combined capacity of the oxide and sulphide plants will be about 540 million lb of copper per year. Twenty one benches have been opened to date and all are still active except the three top ones at the northeastern limit of the pit. These have been pushed back to final slope line. The pit is 8850 ft long, 3540 ft wide and 980 ft deep. Benches are not all developed to a standard height as the large development shovels used in cutting new benches have been of different size and range. At this time new benches 521 ft high are being developed with an&apos; 11-yd shovel. Ore haulage through the greater part of the pit operation has been on down grades to the crushing plant. With the opening of bench F-4 in April 1944 the first adverse-grade ore haul was encountered. Of the total tonnage now being mined, 35 pct comes from the four benches that are below the level of the crushing plant yard. Waste had been dumped on the same or nearly the same level as the bench from which it was removed up to the opening of bench F-4. Waste from this and lower levels is hauled to the level of the crusher, yard where it must cross the flow of ore traffic to reach the only available dumping space to the east of the mine. The average ore haul is 3.13 miles one way shovel to crusher, and the average waste haul from that portion handled by railroad is 3.32 miles one way from shovel to waste dump. Waste that is being removed by truck haulage from the upper part of the -mine is hauled an average of 1 mile. Ore loaded by trucks is hauled 3/4 mile to a car loading ramp and then by rail to the crushing plant. Drilling and Blasting There are two types of development for blasting being used: One for opening new benches and the other for bank shooting. The former consists of 9a in. diam churn-drill holes drilled 11.8 ft center to center in rows 10.2 ft apart with the holes staggered in the rows thus giving an equilateral-triangle pattern of 11.8 ft on a side. After the first block, 492 ft long by 71.5 ft wide, is shot in the pattern described above, the cut is advanced by smaller shots consisting of four rows of holes spaced 23 ft center to center with the rows 23 ft apart. These shots are fired in conjunction with side shots in which the holes are drilled 33 ft center to center and 29.5 ft back from the toe, thus squaring up the bank for subsequent shooting. An average bank shot consists of about 60 holes drilled in two rows parallel to the face, 30 holes to

Jan 1, 1952

By H. R. Cooper

Beginning from the point of view that process control of ore flotation can be approached by on-line analysis of processing behavior, an equation was developed which has characteristics useful for a multi-variable feedback loop. The application of this equation to optimizing control with a data acquisition system will be discussed in Part 11. OBJECTIVE OF CONTROL The purpose of developing a feedback method for concentrator control is to provide a means for determining ore processing behavior in order that data describing the ore can be used to make appropriate changes in control conditions while the ore continues to flow through the flotation circuit. In absence of simple linear relationships between pairs of variables in the flotation process, attention is directed to the need for a generalized relationship which possibly would incorporate all pertinent variables. It would be possible to apply such an equation to the control of variables in a concentrator in real time according to operational requirements as ore gradually changes in quality and processing behavior. To meet this objective, it is necessary to define relationships describing flotation performance in terms of performance variables capable of being measured on-line, either with on-line instruments and analyzers or with manual methods lending themselves to quick determination of meaningful information. Relationships derived to meet this objective form a model for the flotation process. The evaluation of flotation parameters of the ore and the execution of control on the basis of the derived information while the ore is continuing through the process would constitute a feedback control system. Data for the following control and performance variables can be made available: 1) ore feed rate, 2) collector addition rate, 3) lime addition rate, 4) pulp density, 5) assay or multiple assays in feed, tails, or concentrate sufficient for material balancing, 6) particle size distribution in flotation feed, 7) froth height, and 8) frother addition rate. Other process variables, such as flotation air input and mechanical agitation intensity, are usually not considered as control variables and were not taken into account in this analysis. Other data, such as that describing the ore, would be useful for concentrator process control. However, information of this type (such as ore hardness, grain size of the mineral, chemical species of the mineral, and ore surface properties) being not presently measurable in the on-line sense, has the effect of causing disturbances in the system which can be detected only indirectly. The process control system being sought must recognize disturbances by their effect on measured performance followed by determining control changes to compensate for them in meeting the objectives of improved performance (perhaps higher throughput, maximum return, etc.). A suitable model for the process having capability of recognizing the effects of ore disturbances should provide the means for introducing proper compensation through control changes. This would be done by processing on-line data with the model to calculate coefficients reflecting ore characteristics. This procedure can only be applied in a typical flotation system when on-line data can be processed at faster rates than the usual rate at which the ore in flotation feed takes on significantly different characteristics. For example, material balance data can be accumulated in approximately 5-min intervals using on-line X-ray fluorescence analysis. The flotation system time constant might be 15 min including grinding. Ore changes having time constants longer than 1 hr could be accommodated using on-line feedback control by this procedure. FORM OF A FLOTATION MODEL A suitable form for mathematical expression of the flotation process is an equation involving rates, when each of the components entering into the separation can be treated independently by a rate equation. A first-order, kinetic rate equation can be written on

Jan 1, 1967

By C. Y. Wen, H. O. HOPMAN

l. INTRODUCTION. IN casting a thermal balance of the heat generated and absorbed in a blast-furnace treating lead-, copper- and similar non-ferrous ores, assumptions have always to be made for the values of the heat of formation of slag. ? Considering that the larger part of the charge introduced into the furnace comes out in the form of slag, the significance becomes apparent of a lack of heat-values for the singulo-silicate, which is the type of slags commonly made. The aim of the present investigation is to supply these heat-values as far as possible with the apparatus and the time available. The heats of formation of the ferrous and manganous bi-silicates have been determined by Le Chatelier; 1 those of some silicates other than iron and manganese by Tschernobaeff:2 finally Richards 3 gives a figure for a copper blast-furnace slag of known composition. The existing data and those resulting from the present investigation are assembled in Table VI. II. MATERIALS USED. The materials used in the experiments were silica, ferrous oxide, and calcium carbonate. Silica.-The silica sold in the market as chemically pure usually contains small amounts of magnesia, lime, and alumina, and is therefore not suited for the work. The pure material was obtained from clear quartz crystals from Arkansas, broken in a diamond mortar and ground in an agate mortar to pass 1 Comptes rendus, vol. cxx., p. 623 (1895); vol. cxxii., p. SO (1896). 2 Revue de Métallurgie, vol. ii., p. 729 (1905); Electrochemical and Metallurgical Industry, vol. iv., No. 2, p. 72 (Feb., 1906). 3 Electrochemical and Metallurgical Industry, vol. v., No. 7, p. 266 furls?, 1907;) ; Metallurgical Calculations, vol. iii.,.pp. 474, 475 (1908).

Jul 1, 1910

By H. J. de Haan, J. van Lookeren

In view of their size and favorable characteristics, Shell&apos;s heavy-oil fields on the eastern coast of Lake Maracaibo, Venezuela — known as the "Bolivar Coast" — are obvious candidates for the application of thermal recovery methods. During the last decade various methods have been tested, such as steam drive,&apos;, steam soak and in-situ combustion.3 Steam soak was discovered as a promising production method rather accidentally in 1969, during early steam drive testing in the Mene Grande Tar Sands1 When steam erupted at the surface due to breakdown of the overburden, the injection wells were back-flowed to relieve the reservoir pressure. This resulted in high oil production rates, all the more impressive because the reservoir is unproducible by primary means. It was concluded that injection of limited amounts of steam might be a very effective method for stimulation of heavy-oil wells. To obtain information that would be more widely applicable, testing of the process was continued in the eastern part of the Tia Juana field (Fig. 1). Here even more favorable results were obtained than in Mene Grande. This created sufficient confidence to prompt a large-scale project, which was considered essential for an adequate evaluation of ultimate recovery, steam requirements, mechanical problems and economic prospects. To obtain an early answer on the ultimate recovery a fairly depleted area was selected in the western part of the same field ("A" in Fig. 1). The first steam was injected in March, 1964. This paper describes the performance until the end of 1966. The production mechanism and well inflow performance are discussed in some detail. In view of the favorable results obtained so far, steam soak operations have expanded considerably since the start of this project. Presently, five other projects are under way, of which two are about the same size as the one under discussion, with further extensions being programmed. Description of the Project Reservoir Data Shell&apos;s part of the Main Tia Juana reservoir has a proven area of 8,800 acres and an average net oil sand thickness of 130 ft. It contained an initial quantity of 2,750 million bbl of stock tank oil (STOIIP), with an API gravity ranging from 10 to 15 API and a viscosity of 100 to 10,000 cp (at 122F). As a geological unit it is known locally as the Lower Lagun-illas member of the Lagunillas formation, which is early Miocene in age. The sand bodies are believed to be distributary channel sands deposited in a lower coastal plain. Most of the channel sands have lateral and some vertical communication. The field was developed mainly in the period from 1936 to 1950. The ultimate primary recovery is estimated at 18.1 percent of STOIIP, of which 12.5 percent STOIIP had been produced by the end of 1963 from some 540 wells. By then the average pressure had decreased from an initial value of 960 to 550

Jan 1, 1970

By Thomas C. Wilder

Jan 1, 1965

By P. J. Closmann

Steam zone growth as a function of time has been calculated for the case of constant rate steam injection into a preheated reservoir. To simplify the calculation a linear temperature profile has been assumed in the cap and base rock at the start of steam injection. The results indicate that at early times augmentation of steam zone growth due to preheating should be greatest. At longer times the steam zone development becomes close to that calculated with no preheating. INTRODUCTION With the increasing application of thermal recovery processes to recover viscous oil, cyclic steam injection has become important in many large-scale projects. In this process, the cycle of steam injection followed by oil production is repeated a number of times. At the beginning of the second and later cycles, steam is injected into a reservoir that has already been heated but that has lost part of its heat both in produced fluids and by conductive heat loss away from the injection zone. In such a case, the temperature level of the injection zone and the temperature distribution of the surrounding rock will affect the growth of the steam zone developed during the subsequent steam injection. Knowledge of the size of steam zone developed is important in determining the amount of oil displaced and the extent of heating in the reservoir. It is also useful to be able to compute the size of the steam zone for cases where thief zones take most of the injected steam. This paper presents a fairly straightforward method of estimating the steam zone developed in a preheated formation, based on certain simplifying assumptions. Some cases of steam injection into a reservoir at its original temperature have already been considered elsewhere.1-3 Because it is difficult or impossible to obtain an accurate representation of the temperature distribution in the reservoir some time after initial heating has taken place, in this work, a linear temperature profile in the cap and base rock is assumed (Figs. 1A and 1B). The linear profile has the advantage of yielding heat flow equations that

Jan 1, 1969