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By Dorsey Hager, G. W. McPherson

The rapid increase of water troubles in the Mid-Continent oil fields is causing much alarm. Troubles occur at Towanda, Eldorado, Augusta, Cushing, Blackwell, and Healdton, although they had not been acute in the Mid-Continent field until about two years ago, when the unusual conditions in the deeper oil fields were first encountered. California faced the same situation, but, thanks to aggressive measures, has largely overcome the dangers. The following analysis of water trouble may throw some light on the subject and be of assistance in solving the problems involved. Water Troutles Classified The presence of water in large quantities in oil sands has the following results: 1. Diminishes oil production. 2. Diminishes casing-head gasoline production: (a) By curtailing the gas flow. (b) By making the use of vacuum pumps unsuccessful. 3. Increases lifting costs: (a) By making it necessary to pump large quantities of water, which requires a fast motion and long stroke (third hole). (b) By requiring the use of compressors for air lift. (c) By causing break-downs and delays due to the high speed necessary to pump water. (d) By making it necessary to treat "cut" or emulsified oil. Oil production is seriously curtailed by the presence of large quantities of water. Lease records show that wells are shut down 40 to 60 per cent, of the pumping time where serious water trouble occurs. While a small quantity of salt water may cut the paraffine and keep the oil moving, several hundred feet, or a hole full of water, effectually "kills" the oil and gas. The quick return of wells to production, once the water is shut off, shows how wells have been affected. The killing of gas sands

Jan 1, 1920

By J. Mizrahi, A. Brillantshtein, A. Mitzmager, O. Schächter

The separation of synthetic mixtures of heavy minerals by hindered settling classification and jigging was comparatively tested in water and five organic heavy liquids, of various specific gravities and viscosities. It was found that in the hindered settling classification process the separation efficiency was directly proportional to the concentration criterion, the liquid viscosity being a minor factor. There is therefore a decisive advantage in using heavy liquids as classification medium. In the jigging process the advantage of using a heavy liquid is masked by the detrimental effect of a higher liquid viscosity, which, in this case constitutes an important factor. Considerable interest has been aroused lately by the development of mineral beneficiation techniques 1,2 using TBE (tetrabromoethane), a heavy liquid of specific gravity of 2.96, which has been made available for industrial use by a new process3 producing TBE directly from the Dead Sea brines at a reasonable price. Most of the applications investigated until now were based on the sink-float separation of minerals in a heavy liquid of intermediate specific gravity. The TBE can be conveniently diluted with many organic solvents, and thus sharp separations are possible in a wide range of specific gravities up to 2.96. Although this maximum specific gravity is sufficient on most cases for the elimination of the bulk of the barren gangue and the production of marketable concentrates, some practical problems came up for investigation in which the separation of two (or more) minerals, heavier than TBE, was required.* *Among the cases studied in the IMI Laboratorles which fall into this category we can mention: alluvial deposits, such as heavy minerals in sea sand, tin deposits, or ground coarse-grained rocks, such as pegmatites. In such cases where, due to the petrographic structure, further fine grinding is required in order to achieve the liberation of the heavy components, the

Jan 1, 1964

By Ralph Sweetser

IN these days of the almost exclusive use of byproduct coke as the blast-furnace fuel in this country, it may seem out of place, and smacking too much of reminiscing, to say anything about the use of anthracite coal for blast-furnace fuel. Viewed in the light of present day research and of developments in alloy steel, some observations seem appropri-ate regarding this raw material that played such an important part in the development of the iron and steel industry during 50 years of the past century. The research work of that period, in which the whole iron and steel industry was revolutionized, passing from wrought iron to steel and from charcoal to three new mineral fuels for blast furnaces, was done chiefly in the full-sized plants of that day; and it was done largely by the ironmasters themselves. The laboratory had not become a part of the ironworks, and scientific instruments were lacking around the blast fur-naces; "rule o' thumb" and erroneous theories prevailed-and have not yet all been eliminated. The recent interest in meteoric iron in connec-tion with nickel steels and other alloys proves that it is worth while to search for the reasons for excellence and the causes for failures in the metallurgy of bygone days. Turner1 gives the reasons why the blast furnace of Dr. F. W. Geissen-hainer on Silver Creek, Schuylkill County, Pennsylvania, about 10 miles northeast of Pottsville, was operated successfully with anthracite2 in August and September, 1836, and why several other attempts failed. It has taken a long time for us to find out that there are great differences in the behavior of anthracites from the several parts of the anthracite region, as well as differences in coking coals from the bituminous fields.

Jan 1, 1935

By R. S. McCaffery, R. G. Stephenson

The statistical analysis of blast-furnace data was undertaken to determine some of the relations which exist between the variables involved in furnace operation, and particularly to show the effect of variation of slag composition on such economically important factors as coke consumption, daily tonnage of pig iron and sulfur elimination. It' was desired to correlate the results obtained in commercial practice with those predicted from a study of the quaternary system lime-alumina-silica-magnesia. This paper presents the results of a preliminary study of blast-furnace daily operating reports, and is intended to indicate the suitability of our method of attack and something of the results that may be expected from an extended statistical examination of such data. It has been shown that blast-furnace slags are not composed of oxides, as reported by chemical analysis, but are actually composed of several compounds, each made up of two or more of the oxides present.' These compounds persist in the liquid state, and the properties of a slag are the properties of a mixture of these compounds, and not of a mixture of the ultimate oxides. The oxides lime, alumina, silica and magnesia make up 94 to 96 per cent. of the usual blast-furnace slag, and assuming that we may neglect the remainder of the components, we may determine the minerals present, and their relative proportions, from a study of the quaternary system involving these four oxides. Operating reports from 15 furnaces were available for this investigation. Complete slag analyses for one slag per day were available, per-mittling the calculation of the mineral composition of the slags used. Basic, malleable and foundry irons, with silicon varying from 0.75 to 4.50 per cent. were included in the reports for this examination.

Jan 1, 1931

By George I. Adams

A party, consisting of George I. Adams, of the United States Geological Survey, A. H. Purdue, of the University of Arkansas, and Ernest F. Burchard, was engaged, during the summer of 1902, in the study of the zinc- and lead-deposits of Northern Arkansas. An extensive report on this field is now in preparation. The following preliminary statement of results and conclusions is made in advance of the final publication, which will be accompanied by detailed geologic maps and other illustrations and a fuller treatment of the subject. Location.—The Northern Arkansas field embraces Marion county and adjacent portions of Boone, Baxter, Newton and Searcy counties. Outside of this area there are a few scat tered mines, notably in Sharp and Lawrence counties. The mining development lies north of the Boston mountains, in what is known as the Ozark Plateau. The country has a broken surface, as a result of dissection by streams, and there are numerous exposures of the mineral-bearing horizons in the valley slopes. This has greatly facilitated prospecting. History.—Lead-ore was discovered in Northern Arkansas by the early explorers and pioneers, and at first was utilized for rifle-ballets. Later, it attracted considerable attention, and in the '50's was smelted in the vicinity of Lead Hill. There was a revival of the industry during the "70's, but the cost of transportation was so great that it was practically abandoned. Zinc-ores at first attracted little attention, probably because they were not so well understood. Before the Civil War, however, some zinc was smelted. In the '80's, prospecting was carried on generally throughout the field, and resulted in finding zinc at so many places and so readily accessible that

Jan 1, 1904

Correlation between Metallography and Mechanical Testing By H F MOORE (Henry Marion Howe Memorial Lecture Trans, vol 120 11,000 words ) The lack of effective correlation between metallography and mechanical testing from the days of Reaumur to the present is noted, and two general problems of such cor¬relation are stated (1) the correlation of qualitative test results with quantitative, and (2) the correlation of average results with maximum or minimum results Some correlation has been achieved, notably in the field of heat-treatment and in the study of elastic strength of metals Correlation is in the process of being developed in several other fields, including the quantitative study of the effect of grain size of metal on mechanical properties, of grain size and type of crystalline structure on the sensitivity of metals to weakening at holes, notches and other "stress raisers," and in the study of the starting phases of spreading, "fatigue" cracks Correlation of mechanical test results and metallographic study is needed in the study of such problems as the various theories of failure of metals, the meaning of and tests for service ductility of metals, and the relative damaging effect of defects inherent in metals, such as minute cracks and segregation, as compared with the damaging effect of "imposed" stress raisers, such as screw threads, sharp shoulders, etc The neces¬sity for more correlation of metallography and mechanical testing during student days is emphasized, and also the need of a better understanding on the part of engi¬neers of the significance and limitations of metallographic apparatus and results and of X-ray diffraction This should be matched by a better understanding on the part of metallurgists of the significance and limitations of mechanical tests of metals, of testing machines and strain-measuring apparatus

Jan 1, 1937

By D. Grosse

At the beginning of the 1960's, the Hannoversche Portland-Cementfabrik A. G. needed to open a new quarry. The land on which this quarry was to be developed was completely flat and separated from the existing quarry by a navigable canal. The area had been exploration-drilled previously, so that enough reliable data on the chemical properties of the deposit were available. From the geologic point of view, the deposit under a very moist surface belongs to the Turon (Upper Chalk) formation, soft on the surface and medium to very hard farther down. Between the 15% sloping banks of chalk (with a calcium carbonate content of 75 to 90% and running from west to east), there are numerous beds, up to 3 m deep, which are rich in alumina and iron oxide but contain only 50 to 60% CaCO3. In the old quarry-worked conventionally by deep-hole drilling, a 2-cu-m shovel, and 900-mm track with 6-cu-m dump cars-an adequate and modern crushing plant was available. The plant crushed the moist material (11 to 13% H2O content) down to 0 to 50 mm. INSTALLATION OF ORIGINAL MOBILE CRUSHER It was decided to employ a mobile crushing unit in the new quarry; the moist and soft ground did not permit the use of heavy trucks for transporting the material, and a road network would have entailed a large investment. The use of a rail system was eliminated from the beginning, since the ground would be very uneven after the quarry was developed. At that time only one prototype of a crawler-mounted mobile crushing unit existed. This unit was operating in a nearby works as a primary crusher. A similar, slightly improved machine (Fig. 1) was purchased

Jan 1, 1969

RESEMBLING in some respects the enterprise at R Chuquicamata is that of the New Cornelia Copper Co. at Ajo, Arizona. Controlled from its inception by the Calumet & Arizona Mining Co., New Cornelia became a unit of the Phelps Dodge Corporation when the latter absorbed the Calumet & Arizona company in 1931. Both Ajo and Chuquicamata are situated in low mountains in extremely arid desert country. Both ore deposits consisted-the past tense is used advisedly because the oxidized ore has nearly all been mined at Ajo-of a horizon of leachable oxidized ores overlying sulphide or concentrating ore. The principal technical problem in each case was the development of a method for treating the oxidized ore. In both instances the capping of waste rock was comparatively thin and power-shovel mining in open cuts was the obvious method of exploitation. Nature had smiled on neither place in the matter of climate. Though Ajo does not have the persistent winds for which Chuquicamata is notorious, the comforts of living are largely artificial. And it is only fair to emphasize that at each place the mining companies have achieved remarkable success in providing these comforts. Of course, in point of size New Cornelia must be content with the inferior role. From May, 1917, when production was started, to the middle of June, 1930, the company leached 16,368,000 tons of oxidized ore, thereby virtually exhausting the ores of this class. Up to the same date, about 15,000,000 tons of sulphide ore had been mined, and a rough estimate gives 170,000,000 tons remaining in reserve. The total tonnage does not loom very large in comparison with Chuquicamata's billion tons; but it is exceeded by similar figures for only four of the Porphyry group.

Jan 1, 1933

By W. C. Lilliendahl, H. W. Highriter

THE method developed and used in this laboratory for the production of metallic uranium of such purity that it is ductile and can be cold-worked to fine wire or thin sheet by rolling has already been described1. It consists, briefly, in the electrolysis of potassium uranous fluoride (KUF6) in a molten bath composed of equal parts of sodium and calcium chlorides. The bath is contained in a graphite crucible, electrically heated to about 775° C., the crucible serving as the anode for electrolysis. The uranium deposits in finely divided form mixed with salts upon a molybdenum cathode suspended axially in the crucible. Upon completion of the electrolysis the cathode is removed and cooled, the deposit broken and leached to remove salts. The metal powder is washed with water and dilute acetic acid and dried in vacuo to reduce oxidation. Suitable amounts are then pressed into pellets and heated in vacuo by high-frequency induction, using a thoria crucible. The uranium melts and flows away from the pellet, leaving a shell, which is largely oxide. In general, this method produced a satisfactory metal, although at times the uranium was not ductile. The investigations recorded here were made to find the cause of this embrittlement. It was known that the metal generally contained carbon, derived from disintegration of the graphite crucible in which electrolysis is conducted, in amounts dependent upon the thoroughness of washing the metal powder. Accordingly, analyses of several samples, both ductile and brittle, were made by combustion and absorption of CO2 in Ascarite, using air instead of oxygen to reduce the temperature and rate of oxidation. Several of these metals were made with special precautions to reduce carbon content. The results show no relationship between ductility and carbon content in the range investigated (Table 1).

Jan 1, 1935

By B. Ladanyi, G. Archambault

It is generally recognized to date that a rational stability analysis of slopes and foundations in rock masses is a desirable but still rather remote goal of rock mechanics.1 In principle, a slope analysis is possible provided the original state of effective stress in the ground is known and the shear strength of the earth material can be clearly defined. In a macroscopically continuous earth medium such as soil, the two basic ingredients of the stability analysis in most cases can be assessed with sufficient approximation. A much less favorable situation exists when the slope is composed of a macroscopically discontinuous medium such as rock mass containing one or more sets of geological planar structures. In such a case, both the original effective stresses and the overall shear strength of the mass are much more difficult to determine. As for the former, it is only recently that certain calculation methods and solutions concerning the stress distribution2 and the seepage forces3 in a discontinuous medium have been proposed. As the strength behavior of the rock mass is concerned, much valuable effort has been made in recent years toward reaching a proper understanding of the phenomenon of rock mass failure under stress. Probably one of the most complete investigations of the problem to date has recently been made at the University of Illinois. The study resulted in establishing a first useful working hypothesis of the shear behavior of a regularly jointed rock mass, proposed by Patton in 1966.4 The main purpose of the work described in this chapter is to establish a more general framework for the shear behavior of rock mass, one that would be directly related to some basic rock parameters and would also

Jan 1, 1970

By John Gross

The study of the energy used in crushing operations has advanced from a period of perplexing confusion to one of greater clarity. Only within the last few years has any true conception of the work in crushing been possible, owing to the chaotic state of theoretical knowledge. For some 20 years a controversy existed between those advocating the Rittinger law and those advocating the Kick law. The Kick law now appears to be definitely out of the picture, and crushing efficiency may be based confidently on the Rittinger theory. There also seems to be a generally crystallized conception as to the meaning and nature of sub-sieve material. There is needed a simple, direct method for determining surface on a crushed ore product, and also a simple and accepted method for size determination on minus 400-mesh material. The Crushing Law The Rittinger(l)‡ theory of crushing was advanced in 1867 and the Kick(3) theory in 1885. While the Rittinger theory might have been accepted without much question and actually had been accepted by many investigators, a serious doubt as to its validity was raised by Stadler(10) who upon purely theoretical grounds proclaimed the Kick "law" as the true law of crushing. According to Rittinger the energy required in successive steps in reduction increases geometrically, while according to Kick the energy increases arithmetically. These "laws" therefore are at variance, and the establishment of the true law was recognized as of first importance. Many simple experiments have been made to demonstrate the application of the Rittinger theory to crushing, and it would seem that its simplicity should favor its acceptance. Experimental evidence, however, was not convincing, as no reliable data could be obtained on the finer material from a crushing or grinding operation. Gates,(13) Bell,(19)

Jan 1, 1935

By J. Moore Samuel

THE prospective change in ore receipts at the Copper Queen reduction works necessitated a careful study of conditions to determine the most economical method of smelting. The first step, calculating the known, probable, and possible results, showed the economy of a unimetallurgical flow sheet f which the three pyrometallurgical stages would be roasting, reverberatory smelting, and converting. The past and future ore receipts (not including converter flux) are as follows: AVERAGE MONTHLY FUTURE MONTHLY RECEIPTS, 1918 RECEIPTS TONS PER PER CENT. OF TONS PER PER CENT. OF MONTH TOTAL RECEIPTS MONTH TOTAL RECEIPTS Ore 84,553 82.3 43,000 44.0 Gravity concentrates 16,375 15.9 25,500 26.0 Flotation concentrates 1,883 1.8 29,400 30.0 Total 102,811 100.0 97,900 100.0 Of the 102,811 tons per month received in 1918, only 28,945, or 28 per cent., was treated in the roasters and an average f 14.1 roasters out of 20 were in operation; the remaining ore was treated in the blast furnaces. The change to "all reverb." practice, therefore, called for considerable additional roaster capacity, which could be obtained either by building additional units, or by remodelling the present units so as to give increased unit capacity. In view of the progress in roasting practice since the construction of the Copper Queen roaster plant and the heavy investment in that roaster plant, the second plan seemed to be the more desirable. The Copper Queen roaster plant consisted of twenty six-hearth, McDougall roasters, 18 ft. in diameter, equipped with cast-iron arms that originally were water cooled but now are air cooled. They have no top dry hearth and the feed is discharged through the top arch, near its periphery, by plunger feeders from two bins at opposite sides of the roaster.

Jan 7, 1921

By Alan English

INTRODUCTION During the Bicentennial Year in the United States of America, recognition should be given to the fact that 20 years ago the first large-scale commercial pelletizing plant was started and attained rated capacity. This was the beginning of a new industry. Twenty years ago the total production of pellets was principally from pilot plant facilities and totaled in the thousands of tons per year. At the present time the world production is slightly in excess of 280 million tons per year. This truly is a tremendous growth for any industry. Such a production growth obviously is accompanied by a similar growth pattern in the development of process, equipment, and facilities. During the growth and development period, different materials became more adaptable for processing. For example, initially the pelletizing of iron ores revolved around the magnetite concentrates where the heat of reaction constituted a very important part of the process fuel. During this growth period, specular hematite, earthy hematite, mixtures of hematite and magnetite, and even non-ferrous type materials were pelletized, a function previously thought not practical. The demand for the use of pellets has also broadened their concepts. At first they were made to replace the high-grade iron ores used in blast furnaces. Nowadays, not only have they replaced iron units, but they have had a major influence on the design of larger blast furnaces and have contributed to production rates in excess of 10 000 tons per day from a single furnace. They have also been used in the manufacture of steel, principally for coolants in the BOF practice. More recently, with the improved beneficiation techniques that have been developed over the same period of time, pellets have been used for the direct reduction process and can be used directly

Jan 1, 1977

By Alexandre Pourcel

The phenomena of liquation in steel or iron ingots of all sizes, but naturally to greatest extent in the heaviest ingots, have been noticed ever since the commencement on a large scale of the Besse mer and open-hearth manufactures; but they have been studied with care during the last few years only. The English and the Ameri cans were the first to publish the results of investigation upon phe nomena of this clam, to which they have given the name of segregation. Historical. Passing by that which has been written concerning the segregation observed in gray pig-iron, of which instances were given by Karsten, we shall confine ourselves here to that which is known of this subject with exclusive reference to ingot steel and iron. Mr. H. M. Howe, of Boston, in his Metallurgy of Steel, the most complete and well-arranged treatise upon steel, gives a resume of observations, with the results of numerous analyses, bearing upon the phenomena of segregation. According to Tchernoff (with whom we discussed this question at length in 1878, in connection with the cast-steel plates of large dimensions designed for the Italian fleet, which we showed him at Terre-Noire), Kalakoutsky called attention in 1866 to the lack of homogeneity in Bessemer ingots, especially when cast in sand. Our own attention had been called to the phenomena of liquation in 1868 by a somewhat surprising fact which appeared in almost every one of a number of steel-rail ingots coming from the works of Messrs. Pierre and Emile Martin at Sireuil, to be rolled at TerreNoire. In the heating or in the first groove of the rolls, a slice of from 6 to 10 centimeters (2.4 to 3.9 inches) separated itself from the head of each ingot. As a general consequence, the section of

Jan 1, 1894

By K. D. Jacob, H. L. Marshall, D. S. Reynolds

All types of commercial phosphate rock produced throughout the world contain fluorine in quantities ranging from approximately 0.4 to 1.3 per cent in the Curacao and Christmas Island phosphates to 3.1 to 4.2 per cent in the phosphates of the United States and North Africa1. For a given type of rock, the fluorine content is usually roughly proportional to the phosphorus content. Significance of Fluorine in Phosphate Rock On the basis of chemical and X-ray diffraction studies, Hendricks and co-workers2 concluded that fluorapatite, Cal10F2(PO4)6, is the essential phosphatic constituent of the commercial types of domestic phosphate rock. On the other hand, Bredig and co-workers3 have recently advanced the opinion, also based on X-ray diffraction studies, that the mineral phosphates usually contain carbon dioxide in the apatite lattice, and that the phosphate rocks of the United States are really fluorcarbonate apatites. However, the domestic types of phosphate rock do not seem to differ greatly from coarsely crystalline fluorapatite in their behavior toward chemical reagents in general, and for the purpose of this paper it will suffice to consider fluorapatite as being the essential phosphatic constituent of these types of rock. The available data1 indicate that the different commercial types of domestic phosphate rock usually contain about 12 to 52 per cent more fluorine than theoretically is required to form fluorapatite with all the phosphorus. Calcium fluoride (fluorite) has been definitely identified in only a very few of the samples that have been examined1,2. Bredig and co-workers4 state that fluorapatite can take into its crystal lattice excess calcium fluoride to the extent of approximately 70 per cent of that theoretically required by the formula Ca10F²(PO4)6 without causing more

Jan 1, 1938

By Frederick Laist

(Butte Meeting, August, 1913.) WHILE remodeling No. 1 section of the concentrator at the Washoe Reduction Works of the Anaconda Copper Mining Co. during the summer of 1912, for the purpose of ascertaining what additional metal recoveries could be made by improvements in concentration practice which had been developed by the staff of the Boston & Montana Reduction Department, at Great Falls, it was deemed advisable to carry on some experiments on the treatment of the regular mill tailings by roasting and leaching, to see whether the losses of metal values might not be still further decreased. In the course of these experiments about 5,000 tons of tailings were roasted, and of the resulting calcine about 200 tons were leached. The results were so satisfactory that it was decided to continue the work on a larger scale, particularly as regards the leaching end of the process, and construction work on an 80-ton roasting and leaching plant was accordingly commenced during the latter part of February, 1913, and is being pushed as rapidly as possible. 80-Ton Leaching Plant. This plant will consist of one 20-ft. roasting furnace of the MacDougall type, specially adapted to the work of roasting for leaching; two leaching tanks, .32 ft. in diameter by 12 ft, deep, together with the necessary solution tanks, air lifts, precipitating launders, etc. It has been decided to precipitate the copper from solution on scrap iron, so as not to hamper the roasting and leaching departments by any weakness that might develop in the precipitating department. It is, however, the intention to experiment with a number of different methods of precipitation ; for example, by electrolysis and by hydrogen sulphide.

Jan 7, 1913

By Frederick Laist

(Butte Meeting, August; 1913.) WHILE remodeling No. 1 section of the concentrator at the Washoe Reduction Works of the Anaconda Copper Mining Co. during the summer of 1912, for the purpose of ascertaining what additional metal recoveries could be made by improvements in concentration practice which had been developed by the staff of the Boston & Montana Reduction Department, at Great Falls, it was deemed advisable to carry on some experiments on the -treatment of the regular mill tailings by roasting and leaching, to see whether the losses of metal values might not be still further decreased. In the course of these experiments about 5,000 tons of tailings were roasted, and of the resulting calcine about 200 tons were leached. The results were so satisfactory that it was, decided to continue the work on a larger scale, particularly as regards the leaching end of the process, and construction work on an 80-ton roasting and leaching plant was accordingly commenced during the latter part of February, 1913, and is being pushed as rapidly as possible. 80-Ton Leaching Plant. This plant will consist of one 20-ft. roasting furnace of the MacDougall type, specially adapted to the work of roasting for leaching; two leaching tanks, 32 ft. in diameter by 12 ft. deep, together with the necessary solution tanks, air lifts, precipitating launders, etc. It has been decided to precipitate the copper from solution on scrap iron, so as not to hamper the roasting and leaching departments by any weakness that might develop in the precipitating department. It is, however, the intention to experiment with a number of different methods of precipitation; for example, by electrolysis and by hydrogen sulphide.

Jan 7, 1913

By Edgar Trask

EACH branch of engineering seems to depend on the cooperation and contribution of some other branches to enable it to produce more efficient methods and appliances for man to use. The purpose of this paper is to show approximately the gain in efficiency of self-propelled merchant ships when steel of greater elasticity is substituted for mild steel in some of the strength members and alu-minum alloy is substituted in some of the parts where strength is not essential. The new steel will have some greater strength and a much greater elastic limit in the as-rolled condition, and must be readily weld-able under ordinary conditions of shipbuilding. Naturally, its cost may be more than mild steel, but if the demand is great that excess cost may be reduced to an amount that will make its use more economical than that of the present mild steel. There appears to be a well defined axiom in engineering today that to use the least power to carry a given load the weight of the carrier must be reduced to a minimum. This minimum must be, of course, consistent with the necessary strength, rigidity and durability and it must not be attained at an excessive cost where the fixed charges of the carrier will exceed the savings in, operating the motive power. Recent railroad equipment is a notable example of this, and in these trains alloy steels and aluminum together with less weight per horsepower of the power plant are reducing the weight of the carrier and hence the total power required for moving the paying load. Before considering the application of these metals to shipbuilding, it is well to explain some of the fundamentals of ship design.

Jan 1, 1936

By D. S. Reynolds, K. D. Jacob, H. L. Marshall

All types of commercial phosphate rock produced throughout the world contain fluorine in quantities ranging from approximately 0.4 to 1.3 per cent in the Curacao and Christmas Island phosphates to 3.1 to 4.2 per cent in the phosphates of the United States and North Africa1. For a given type of rock, the fluorine content is usually roughly proportional to the phosphorus content. Significance of Fluorine in Phosphate Rock On the basis of chemical and X-ray diffraction studies, Hendricks and co-workers2 concluded that fluorapatite, Cal10F2(PO4)6, is the essential phosphatic constituent of the commercial types of domestic phosphate rock. On the other hand, Bredig and co-workers3 have recently advanced the opinion, also based on X-ray diffraction studies, that the mineral phosphates usually contain carbon dioxide in the apatite lattice, and that the phosphate rocks of the United States are really fluorcarbonate apatites. However, the domestic types of phosphate rock do not seem to differ greatly from coarsely crystalline fluorapatite in their behavior toward chemical reagents in general, and for the purpose of this paper it will suffice to consider fluorapatite as being the essential phosphatic constituent of these types of rock. The available data1 indicate that the different commercial types of domestic phosphate rock usually contain about 12 to 52 per cent more fluorine than theoretically is required to form fluorapatite with all the phosphorus. Calcium fluoride (fluorite) has been definitely identified in only a very few of the samples that have been examined1,2. Bredig and co-workers4 state that fluorapatite can take into its crystal lattice excess calcium fluoride to the extent of approximately 70 per cent of that theoretically required by the formula Ca10F²(PO4)6 without causing more

Jan 1, 1938

By M. C. Leverett

The behavior of mixtures of immiscible liquids in porous solids is of rapidly increasing interest to those engaged in the production of petroleum. The operation of artificial water-floods and the control of natural ones immediately raise questions concerning the fundamental nature of such processes. Moreover, it is now recognized that often water occurs dispersed throughout the rock from which the oil issues into the well,' and thus tends to move toward the well simultaneously with the oil. The work reported here is a laboratory investigation of the simultaneous, steady-state flow of oil and water through the same column of uncon-solidated sand. It is thus directly related to the situation in which water occurs in oil-producing sands; it may have less direct implications for the displacement of oil from sands by water. However, it is to be clearly understood that the experiments to be described were performed primarily to obtain information of a more or less fundamental nature, and are not an attempt to reproduce, on laboratory scale, any part of an oil field. The dynamic behavior of a system in which oil and water are flowing simultaneously through sand is best described in terms of its "effective permeability" to either phase. For incompressible fluids flowing through a system of uniform cross section, the effective permeabilities to the two phases, in darcys, may be defined by the equations: Ko = PA6A [la] and Ku = Q [lb] In order to put the results obtained on a comparable basis for different sands, the effective permeabilities will be stated as fractions of the normal permeability of the sand; i.e., fractions of its permeability to a homogeneous fluid. Algebraically, these fractions are: KO' = Ko/K, and KWr = K,/X [2a] and [Zb]

Jan 1, 1939