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By R. E. Steiner, A. F. Weinberg, R. J. Van Thyne

Uranium solubility in molten bismuth was determined in the temperature range 350" to 600°C, varying from 0.09 wt pct to near 2 wl pct, respectively. Zirconium and magnesium, simulated fission products, and sodium were found to increase or decrease uranium solubility in bismuth in the temperature range 370° to 420°C, depending upon the addition or temperature. Data were obtained by both chemical analysis of samples obtained by filtration from saturated melts and by measurement of the variation of electrical resistance with temperature. IN a study for the United States Atomic Energy Commission, a Liquid Metal Fuel Reactor Experiment (LMFRE) was proposed in which a solution of uranium dissolved in molten bismuth served as both the fuel solution and the primary coolant. It was proven necessary to add other elements to this solution for certain desirable properties: 1) zirconium acts to prevent reaction of the fuel solution with the graphite core (which would result in the formation of uranium carbide) and also to inhibit mass transfer of iron and chromium from the walls of the reactor tubing to cold spots resulting in blockage; and 2) magnesium acts as a deoxidant and prevents loss of uranium. In addition to these intentional additives, other elements entering the solution are: 1) fission products which are a by-productof reactor operation, 2) sodium (the secondary coolant) through possible small leaks in the heat exchange system, and 3) iron and chromium from the container walls. Each of these elements may affect the solubility of uranium in the fuel solution. Since the concept of this reactor is based upon a liquid solution, the relatively low solubility of uranium in bismuth will dictate the minimum temperature at which the reactor heat exchanger can be operated. The solubility of uranium in liquid bismuth and the effect of some additives on this solubility have pre- viously been investigated1-' (more recent results6" became avaliable after initiation of this investigation). However, some discrepancies between the various results have been noted, and also the cumulative effect of the several additions or impurities was not known. This investigation was commenced to obtain definitive results. MATERIALS Analyses of the materials used are presented in Table I. Although ostensibly of extreme purity (99.999 wt pct), the bismuth was found to contain a significant amount of impurities, probably oxides. Except for determination of the binary system, Bi-U, prior to use all bismuth was hydrogen-refined and

Jan 1, 1962

By R. Dawson Hall

Discussion of the paper of R. DAWSON HALL, presented at the San Francisco meeting, September, 1915, and at the New York meeting, February, 1916, and printed in Bulletin No. 105, September, 1915, pp. 2013 to 2021. R. DAWSON HALL, New York, N. Y.-The general practice in the past has been to view the roof as being somewhat subject only to shear. In fact the action of the roof under the stress of its own weight has been but little considered, not because the matter is unimportant but because it is so complicated that it has been felt that an analysis of it would not result in any conclusions definite enough to justify the inquiry. The result has been that the consideration of the subject has fallen into the hands of persons who are not experts in the study of beam and plate stress. They have been disposed naturally to view the destruction of the roof as the outcome of the simplest of stresses-vertical shear. In the lack of a careful consideration of the conditions of roof fracture it was thought that the roof consisted of a number of horizontal layers, which were each of them weak, because, no matter how strong they might be they usually lacked sufficient depth. This view of the condition of the roof would naturally lead one to expect that it would yield to bending moment, the various layers succumbing one by one to their lack of the necessary radius of gyration to meet such severe stresses. But,

Jan 5, 1916

The early history of coal in West Virginia is all included with that of Virginia in the few records available but for present-day readers it is much more convenient that the account of this area prior to the Civil War be grouped with that since then. West Virginia shares with Maryland in the first record of coal noted in the Appalachian fields. This was along the upper Potomac River, in the fall of 1736, and the data about it are given under Maryland, as most' of the development of the area was in that state. The next record of coal was left by John Peter Salley in his account of the expedition he made with Howard and others in 1742. (See p. 17.) The next reference found is that of Dr. Thomas Walker, in 1750, when he passed through the Pocahontas coal field. This has been described on page 18. Six years later, in March 1756, Capt. William Preston, who was with Major Lewis in his expedition down Big Sandy River, wrote in his journal: "Tuesday 2.... Moved down the branch and- came to the main creek where we camped. Put on half rations. Came into the Cole land; crossed the river 8 times."1 The party crossed from the head of Clinch River to Horse Pen Creek, then to Jacob's Fork and down it to Dry Fork of Tug River; the coal was seen in what is now McDowell County. The early settlers must have known of the presence of the great Pittsburgh bed in the northern part of the state, both along the Monongahela River and elsewhere, because the outcrops could easily be seen along streams in many. places. The report of the Commissioners for Adjusting Claims to Unpatented Lands, made in 1789, contains several references to coal in the names of streams, made years earlier. The earliest is one for 1,000 acres to James Walker, in Monongalia County, "adjoining his settlement on a branch of the right hand fork of Pappaw known by the name of the Stone Cole Lick made in the year 1773."2 Another of 400 acres in the same locality was settled upon in 1777.2 A third spoke of a tract "on the left hand fork of Stone Cole about three miles from the mouth," in 1783.1 Monongalia County then covered all of the northern

Jan 1, 1942

By Kenneth A. Gutschick, Robert S. Boynton

Lime has become a very general loosely used term that includes virtually all finely divided types of limestone as well as burned forms of lime. However, actually (and according to Webster) lime is only calcined limestone (known as quicklime, calcium oxide, or calcia). It also embraces the secondary product of quicklime-namely hydrated lime or slaked lime (calcium hydroxide). Fundamentally there are two basic types of limestone-high calcium and high magnesium (dolomitic). The dolomitic quicklimes and hydrated limes correspond to their "high calcium" counterparts in terminology. The only difference is that the dolomitic types are a combination of the elements, calcium and magnesium, whereas high calcium limes contain only 0.5 to 2 pct of magnesium. Both types, which are made through calcination at high temperatures, are shown chemically as follows: [ ] In the above reactions either type of limestone is burned (calcined) in furnaces known as lime kilns so that the carbon dioxide content of the stone is expelled as a gas. With high calcium limestone 44 pct of the weight of the stone is lost; with dolomitic limestone the loss is 48 pct. Also, both reactions are chemically reversible since quicklime absorbs carbon dioxide readily and in so doing transforms itself back to the original carbonate form. Most quicklimes correspond in size to the original rock, which varies from one to eight inches, depending upon the type of kiln employed. Slight shrinkage occurs during calcination. A few limestones when calcined will decrepitate (break down) into a fine powdery form; however, chemically it is the same as the pebble or lump-sized material. For some uses the lumps of quicklime are pulverized and packaged. Since quicklime has great affinity for moisture and carbon dioxide, it is perishable. When it absorbs moisture and CO2 slowly from the atmosphere, the resulting product is "airslaked." Consequently, it must be stored in dry, moisture-proof areas that are free from CO2. Because of its fugitive nature, it is usually consumed within a few weeks after manufacture. A more stable form of lime is hydrated lime-commercially made by adding water to the quicklime until the lumps break down into a fine, white powder. This product, which is usually packaged, can be stored more safely; and many of its uses are interchangeable with quicklime. The irreversible chemical reactions of hydrated lime for both high calcium and dolomitic types are: [ ]

Jan 1, 1960

IN A broad sense, the subject of slag control includes not only the adjustment of the composition of the slag but also of its relative weight in terms of percentage of the metal-bath weight. The slag is made up essentially of (1) oxides formed by oxidation of silicon, manganese, phosphorus, and iron in the charge, (2) SiO2, MnO, and other oxides charged as such, and (3) lime charged or fed to the heat to neutralize the “acidic”: oxides present (Si02 and P2O5). Obviously, if practically perfect control were possible over the composition of the charge as well as over the oxidation process during the melting period, both slag weight and composition would be very nearly predetermined, and the control problem would be solved. Unfortunately, we have only a somewhat. imperfect control over these factors, so that beginning at about the lime-boil period in the heat, and later in the early refining period, it becomes necessary for the first helper, as the heat progresses, to make quick estimates of the composition and physical state of development of the slag (as well as of the amounts of phosphorus, sulphur, and carbon in the metal) from which he can judge how much extra lime, roll scale, fluorspar, and other additions will be needed not only to give the desired final slag composition, but also to hasten the complete fusion or shaping to a desired viscosity in the liquid state. The discussion in this chapter is limited essentially to those more or less practical rapid methods of slag estimation that have been used, or at least tried, for these purposes under actual open-hearth shop conditions. Another aspect of importance here is the extent to which the freedom of choice to the operator is limited by available charge materials, product specifications, and the oxidation and other chemical- reaction effects which inevitably occur under the conditions of this furnace process. For a better understanding of these control limitations and of the chemical and physical background of the subject, the reader is urged to read at least part of the discussion in Chapters XVII and XIX. Charge materials are discussed in Chapter IV, and many of the details of charging, melting, and refining practice closely related to slag control are given in Chapters VI and VII.

Jan 1, 1944

By George A. Connell

BORAX, a sodium borate and the principal sodium salt of boric acid, has been surrounded with romance and with a certain amount of mystery. Its early history is not entirely known but it has been contended that Marco Polo in his travels in the Orient introduced this material to the West during the Middle Ages. Without doubt its first source was from Central or Eastern Asia and perhaps from Tibet. The well-known fluxing properties of borax probably introduced its earliest use that of a soldering flux in the manufacture of jewelry. This use, as well as the remote location of most borate deposits, added greatly to the romance associated with the thought of borax. COMPOSITION The common element in all borates is boron but this element has never been discovered as such in any deposit, because of its great affinity for oxygen. Incidentally, this makes its manufacture extremely difficult and expensive. Elemental boron undoubtedly has many properties that make it quite valuable but the extreme cost involved in producing it from its oxidized form prevents its general use or manufacture. The common element in all borates is boron but this element has never been discovered as such in any deposit, because of its great affinity for oxygen. Incidentally, this makes its manufacture extremely difficult and expensive. Elemental boron undoubtedly has many properties that make it quite valuable but the extreme cost involved in producing it from its oxidized form prevents its general use or manufacture. The common element in all borates is boron but this element has never been discovered as such in any deposit, because of its great affinity for oxygen. Incidentally, this makes its manufacture extremely difficult and expensive. Elemental boron undoubtedly has many properties that make it quite valuable but the extreme cost involved in producing it from its oxidized form prevents its general use or manufacture of disodium tetraborate (Na2B4O7.10H2O), and, further, can be considered as the acid salt of monosodium metaborate. However, the term "acid salt" might imply that borax gives an acid reaction in solution, which is not true, since solutions of borax are decidedly alkaline, giving a pH of 9.2. Boric acid, also known as boracic acid, has the chemical formula H3BO3; it occurs in nature as the mineral sassolite. Sassolite has been

Jan 1, 1949

Cortez Gold Mines operated a conventional 2,100 mtpd (2, 300 stpd) cyanidation plant until the 5 million ton ore body was worked out in 1973. (See Gold and Silver Cyanidation Plant Practice by F. W. McQuiston, Jr. and R. S. Shoemaker, Society of Mining Engineers, AIME 1975.) Sub-grade material was dump leached at the mine -mill location in 1971, and the resulting pregnant solutions were added to the feed in the plant's Merrill-Crowe precipitation unit for gold recovery. In early 1973, however, Cortez put into operation their Gold Acres mine which was located about 13 krn (8 miles) to the west of the 'Cortez mine. Economics at that time dictated the heap leaching of the lower grade portion of the ore body with the higher grade being trucked to the Cortez plant for milling. Leach ore was moved directly from the open pits to prepared leach pads located on a gently sloping terrain of 570 grade. Preliminary pad preparation at the leach site included removal of vegetation which was composed of sagebrush and grading of the base. Pads were comprised of mostly minus 74 micron (200 mesh) materials and were made of clay-silt or slime tailings spread on the pad area in thin 50 to 75 mm (2 to 3 in. ) layers, compacted with a vibrating roller compactor to a depth of about 380 mm (15 in.). This was followed with a 100 mrn (4 in.) layer of coarse rock to prevent erosion on the pad and to allow solutions to move laterally under the heaps. Leach solutions normally traveled the length of the heaps and were collected in plastic-lined ditches from which they flowed by gravity to the pregnant solution storage pond. Both pregnant and barren ponds were constructed in the same manner as the leach pads - being lined with compacted tailings or clay silts. The Gold Acres facility required pregnant solution storage of 6 million liters (1.6 million gal) and barren storage of 3.8 million liters (1.0 million gal) designed to handle two to three days of heap drainage or to retain run-off from a major rainfall. Various heap heights were tried including 3, 6, and 9 meters (10, 20, and 30 ft), with a 6 m (20 ft) height selected. Ore was dumped by trucks in a single 6 m (20 ft) lift using a D8 Caterpillar dozer for

Jan 1, 1981

The papers that appear on pages 326 through 367 were presented at two joint meetings of the Mineral Industry Education Division, Geophysics Committee, the American Geophysical Union and the Committee on College Curricula of the American Association of Petroleum Geologists, at the A.I.M.E. meeting in New York on Feb. 17 and 18, 1941. At the first meeting, the Mining Geology Committee, the Society of Economic Geologists and the Committee on Applications of Geology of the ilmerican Association of Petroleum Geologists also took part.

Jan 1, 1946

The papers that appear on pages 326 through 367 were presented at two joint meetings of the Mineral Industry Education Division, Geophysics Committee, the American Geophysical Union and the Committee on College Curricula of the American Association of Petroleum Geologists, at the A.I.M.E. meeting in New York on Feb. 17 and 18, 1941. At the first meeting, the Mining Geology Committee, the Society of Economic Geologists and the Committee on Applications of Geology of the ilmerican Association of Petroleum Geologists also took part.

Jan 1, 1946

R. W. NEWCOMB, New York, N. Y. (written discussion *).-In this paper, the author has enumerated the various sources of error that may, under certain conditions, develop in instruments of the direct-deflection type, but through a failure to mention possible sources of error in instru-ments of the potentiometer type, he leaves the reader with a wrong im-pression. If he would carry his criticisms further and give a list of the possible sources of error on potentiometer instruments, the paper would be more complete.

Jan 12, 1919

The Institute should feel honored that one of its distinguished members, Auguste J. Rossi, has been awarded the Perkin Medal of the Society of Chemical Industry. The medal was presented at a meeting of the New York Section of the Society on Jan. 18, at the Chemists' Club. Mr. F. A. J. Fitzgerald, Past President of the American Electrochemical Society; described the work of Mr. Rossi, while the presentation address was delivered by William H. Nichols, Past President of the Society of Chemical Industry.

Jan 2, 1918

PROF RICHARD ÅKERMAN Stockholm, Sweden DR FRANK DAWSON ADAMS Montreal, Canada PROF HATON DE LA GOUPILLIERE Paris, France SIR ROBERT A. HADFEILD London, England HERBERT C. HOOVER Leoben, Austria ROBERT W. HUNT Chicago, ILL JAMES FURMAN KEMP New York, N.Y. PROF HENRI LOUIS LE CHATELIER Paris France EZEQUIEL ORDONEZ Mexico City, Mexico ALEXANDRE, POURCEL Paris, France PROF RICHARD H, RICHARDS Boston Mass. JOHN E. STEAD Middlesborugh, England PROF DIMITRY CONSTANTIN TSCHERNOFF St Petersburg, Russia PROF TSUNASHIRO WADA Tokyo, Japan CHARLES D WALCOT Washington D.C.

Jan 1, 1923

This symposium is based on material presented at the AIME Annual Meeting in New York, February 1958. Co-Chairmen of the panel discussion were Truman H. Kuhn, Colorado School of Mines, and J. E. Monroe, Freeport Sulphur Co. Panel members are listed above. In opening the meeting Chairman Monroe pointed out that both industry and education have their special problems and that the purpose of this and similar discussion groups is to bring together members from both industry and education in order to help solve their problems.

Jan 6, 1958

By R. S. French, W. R. Hibbard

M. Balicki—As one who some years ago spent much time searching for an alloy with high thermoelectric power that would be suitable for heat energy-electric energy converter based on the principle of a thermoelectric pile, I would like to make a few comments touching upon that aspect of this excellent paper. The specifications which one of the authors has formulated so aptly do not appear to me as complete, and I would like to add to them the following two demands: (1) Melting point not less than 500°C and (2) elongation on 2 in. at least 5 pct. Condition 1 would insure good thermodynamic efficiency of the pile by permitting a reasonably high temperature of the hot junction and at the same time making it suitable for such application as salvage of vast amounts of energy which is lost in the form of sensible heat of waste gas leaving industrial and other furnaces. Condition 2 is also a very important one; particularly, because of the fact that all elements and alloys which exhibit attractive thermoelectric properties seem to be as a rule very brittle. The design, erection, and maintenance of a pile incorporating a brittle material in one of the most crucial parts of the converter would be a very difficult and costly affair indeed. To illustrate this point I may mention great difficulties I encountered when trying to make thermocouples of silicon. Casting of 1/4-in. rods in iron or graphite mould yielded only broken pieces which had to be welded into a bar. Such a bar had to be handled very carefully during the determinations. Raising the molten silicon by vacuum into a silica tube and solidifying it there solved the problem of stability as well as that of electrical insulation of a bar. On tests this bar (98.5 pct Si) showed dE/dT = — 275.5 microvolts per degree C vs. copper. Thermocouples made of this grade of silicon and pure nickel developed 0.39 v when temperature of the hot junction was approximately 1000°C. The possibility Dr. Gonser has mentioned of trying to impart to metals good thermoelectric properties by alloying them with silicon, has been considered. The preliminary survey which I have made was, however, disappointing. Perhaps, it will be advisable to record the results obtained (table VI), as this might save repetition of search in fields already covered.

Jan 1, 1951

By R. W. Smith, G. W. Delamore, J. A. Spittle

RECENT work by the authors1 has demonstrated that the crystals constituting the equiaxed zone in small ingots originate, on quenching, in the chilled liquid. Whether any partial remelting2 takes place of the den-drites nucleated in the chilled region was not examined. However, the claim3 that this normally occurs, leading to crystal multiplication, has been disputed.4 Thus, for an equiaxed zone to form in the central region of an otherwise columnar ingot, it is necessary to transport crystallites from the chill zone to this region. In view of the work of Uhlmann et al.,5 it was considered desirable to examine the transport process further. Experimental Technique and Results. In the earlier experiments by the authors.1 a stainless-steel crucible 17/8 in. diam, 41/2 in. high, ad containing an alloy of A1-4 wt pct Cu, was quenched from 660°C into a bath of Wood's metal maintained at 100°C. Under these conditions a central zone of equiaxed crystals was obtained. However, if a 2250-G unidirectional magnetic field was applied for 2 sec immediately following the instant of quenching, or subsequently, the equiaxed zone did not appear. Careful thermal analysis showed that the short application of the field had virtually no effect on the thermal conditions of the melt. It thus appeared that the crystallites which were ultimately to grow large enough to form the equiaxed zone existed in the liquid immediately ahead of the interface, occlusion being prevented by the convective fluid flow induced by freezing from the walls of the cylinder. When this relative movement was prevented by the Lorenz forces induced by the application of the magnetic field, the crystallites were caught up in the rapidly advancing dendrite solid-liquid interface. To test this assumption, a small ingot of super-purity aluminum was partially melted and poured into a heated stainless-steel mold which was then immediately quenched into molten Wood's alloy. The resulting structure is shown in Fig. 1, and consists of columnar grains with a central fine-grained zone. Thus the unmelted solid present at the beginning of solidification had been transported ahead of the columnar interface. Discussion. There appears to be little or no information available on the interaction of suspended particles with a metallic solid/liquid interface. However, some information is available for transparent organic sys-

Jan 1, 1969

By B. D. Cullity, J. T. Norton, M. Telkes

M. Balicki—As one who some years ago spent much time searching for an alloy with high thermoelectric power that would be suitable for heat energy-electric energy converter based on the principle of a thermoelectric pile, I would like to make a few comments touching upon that aspect of this excellent paper. The specifications which one of the authors has formulated so aptly do not appear to me as complete, and I would like to add to them the following two demands: (1) Melting point not less than 500°C and (2) elongation on 2 in. at least 5 pct. Condition 1 would insure good thermodynamic efficiency of the pile by permitting a reasonably high temperature of the hot junction and at the same time making it suitable for such application as salvage of vast amounts of energy which is lost in the form of sensible heat of waste gas leaving industrial and other furnaces. Condition 2 is also a very important one; particularly, because of the fact that all elements and alloys which exhibit attractive thermoelectric properties seem to be as a rule very brittle. The design, erection, and maintenance of a pile incorporating a brittle material in one of the most crucial parts of the converter would be a very difficult and costly affair indeed. To illustrate this point I may mention great difficulties I encountered when trying to make thermocouples of silicon. Casting of 1/4-in. rods in iron or graphite mould yielded only broken pieces which had to be welded into a bar. Such a bar had to be handled very carefully during the determinations. Raising the molten silicon by vacuum into a silica tube and solidifying it there solved the problem of stability as well as that of electrical insulation of a bar. On tests this bar (98.5 pct Si) showed dE/dT = — 275.5 microvolts per degree C vs. copper. Thermocouples made of this grade of silicon and pure nickel developed 0.39 v when temperature of the hot junction was approximately 1000°C. The possibility Dr. Gonser has mentioned of trying to impart to metals good thermoelectric properties by alloying them with silicon, has been considered. The preliminary survey which I have made was, however, disappointing. Perhaps, it will be advisable to record the results obtained (table VI), as this might save repetition of search in fields already covered.

Jan 1, 1951

By J. H. Hamilton, J. R. Lewis, J. C. Nixon, C. L. Graverson

Recently there has been much speculation concerning the advantages of using oxygen enriched air or pure oxygen in pyrometallurgical processes. The advantage of using oxygen in the iron blast furnace and elsewhere in ferrous production metallurgy has been given careful consideration and, as a result, several experiments have been tried and a number of papers have recently appeared on this subject.1,2 The use of oxygen in nonferrous smelting likewise poses interesting problems, therefore any experimental data obtained in this area should likewise be of general interest.3 Ashcroft4 in 1933 claimed to have obtained improved results when copper concentrates were roasted in pure oxygen. However, his paper gives neither data nor experimental details. A few years ago a research program was started in this laboratory which had for its objective the determination of the mechanism of oxidation of metallic sulphides under varying conditions. To date we have studied the oxidation of galena,5 sphalerite, and chalcocite. It is a well known fact that copper sul-phde minerals are oxidized slowly by weathering agents, so that the sulphides of copper which find their way into a tailing pond are gradually changed into water-soluble and acid-soluble compounds. Commercially, the oxidation of copper sulphide minerals is accomplished by roasting them at elevated temperatures in air using a suitable (usually multiple hearth) roaster. Most copper smelters are equipped with such roasters. In this phase of the study we were especially interested in determining the effect of temperature on: (I) the air oxidation of chalcocite and (2) the oxidation of chalcocite using commercial oxygen. The amount of sulphur removed as sulphur dioxide, the percentages of water-soluble copper, and of acid-soluble copper were determined for the air oxidation tests. In the tests using commercial oxygen, the percentages of sulphur dioxide, water-soluble copper, acid-soluble copper, water-soluble sulphur and acid-soluble sulphur were determined. For these experiments the temperature was varied from 250 to 700°C. Experimental Preparalion of Chalcocite (Cu2S) Natural chalcocite is not pure, Minerals such as bornite, covellite, and chalcopy-rite may be present. It was decided, therefore, to prepare some chalcocite in our own laboratory. An intimate mixture of sulphur and hool divided metallic copper in the ratio of 4 g of copper to I g of sulphur was prepared. TO this was added a slight excess of

Jan 1, 1949

By J. F. Keefe, C. J. Bier, O&apos

This study was carried out with copper because it represents the simplest form of sintering, in that but one metal is involved and all reactions occur in the solid state. The present work will cover three variables affecting the sintering process; namely, briquetting pressure, sintering temperature and time in hot zone. Although strength and dimensional changes were observed, this is primarily a metal-lographic study of the sintering process in copper. The term "sintering" should be understood to mean the process by which the metal powder particles of the compact become united into one body. Material Used The copper powder used was made from reduced copper oxide, and is typical of a grade used for the mass production of parts formed of metal powders. The screen analysis of the powder was as follows: Per Cent Per Cent BY BY Particle Size "Weight Particle Size "Weight Mesh Microns /80.... 0.00 43/32.... 17.49 80/I00..... 32/20......16.68 100/140.... 0.34 20/10.... 23.14 140/200___ 15.25 10/5..... 4.64 200/230....... 5.00 5/0...... 0.75 230/325.... 16.70 — 325....62. 69 The minus 325-mesh analysis was made by using a Roller Air Analyzer.1,2 The apparent density is here defined as the weight per cubic centimeter of the loose, unpacked powder as measured with the Hall flowmeter. The value for the powder used was 2.57 grams per cubic centimeter.

Jan 1, 1945

By V. V. Valleroy, A. J. Cornelius, B. T. Willman, G. W. Runberg, L. W. Powers

This paper reports the results of an investigation into the use of steam as a recovery agent. High oil recoveries by steam, as much as 100 per cent greater than by water flood, were demonstrated in laboratory linear cores. The principal mechanisms responsible for the additional oil have been identified as (1) thermal expansion of the oil, (2) viscosity reduction and (3) steam distillation. Although the first two also enhance recovery by hot water flood, they are effective with steam injection at lower volumes of produced fluids. Steam-zone residual oil saturation is independent of initial saturation. Recovery by steam is greater for lighter oils because they contain a greater fraction of steam-distillable components. Equations for the steam-zone advance in a radial homogeneous system are presented; these show the effect of reservoir parameters. The displacement in the hot liquid region moving ahead of the steam front can be estimated by a calculative procedure which is suggested. The method which takes account of the temperature gradient is applicable also to a regullar hot water flood. INTRODUCTION Considerable industry interest in the application of heat to petroleum reservoirs as a means of increasing oil recovery has been evident in the past few years. Three thermal methods which have attracted interest are (1) the injection of saturated steam, (2) the injection of hot water and (3) the injection of air into a formation to support combustion within the reservoir. Much has been published in recent years on underground burning, and there have been several papers on hot water injection. Although there are several early reports1,2 on steam injection, no recent experimental studies have been published on this recovery method. In our early thermal methods research, a marked improvement was found in oil recovery by steam injection compared with recovery by water injection in the same system. An investigation subsequently was undertaken to obtain quantitative information from which to evaluate steam injection as an oil recovery method. In addition, it was desired to investigate the recovery mechanism of hot water as compared with that of "cold" water and steam injection. An understanding of the mechanisms by which these processes operate would generally define favorable field conditions for their successful application. This paper reports the results of the laboratory study and suggests calculative approaches to estimate the field behavior of the steam-injection process. EXPERIMENTAL METHOD EQUIPMENT A schematic diagram of the equipment used for the displacement tests is shown in Fig. 1. Essentially, it consisted of a core with suitable means for recording temperatures, a feed system for injecting steam or cold or hot water, and a receiving train for condensing, cooling and measuring produced fluids. For the steam experiments, air-free saturated steam was piped from the boiler to the core face in insulated lines that were provided with steam traps and bleeds to remove any condensate formed in the lines due to heat losses. A 12-in. section of the line immediately ahead of

THE following employment items are made available to AIME on a non-profit basis by the Engineering Societies Personnel Service, Inc., operating in cooperation with the Four Founder Societies. Local offices of the Personnel Service are at 8 W. 40th St., New York 18; 100 Farnswarth Ave., Detroit; 57 Past St., San-Francisco; 84 E. Randalph St., Chicago 1. Applicants should address all mail to the proper key numbers in care of the New York Office and include 6c in stamps far forwarding and returning application. The applicant agrees, if placed in a position by means of the Service, to pay the placement fee listed by the Service. AIME members may secure a weekly bulletin of positions available far $3.50 a quarter, $12 a year. MEN AVAILABLE Graduate Mining Engineer, 38; married, two children, Dutch nationality. Experience bauxite open-pit dragline, stripping and mining, nickel silicateous ore exploration, tin lode mining and dredging, ore dressing research, administrative. work, all in responsible positions. Read, write and/or speak seven languages. Desires responsible position. Presently located Netherlands. M-655. Mining Geologist, 35, married, 3 children, Canadian citizen. Eight years' experience Canadian gold mines as geologist, chief engineer, shift boss, 3 years in western U. S. as surveyor, junior geologist, etc. Desires position of responsibility. Prefer western United States. M-656-478-E-3-San Francisco. Mining Engineer, 30 years' experience open-pit and underground coal and iron mines. Held positions engineer to manager. Desire position of responsibility in foreign field. M-659.

Jan 1, 1952