Search Documents

By E. M. Wise

The practice of adding moderate quantities of nickel to a variety of bronzes has been employed by foundrymen for many years with several objects in view. In some instances it was desired to harden the alloy; in others it was to increase the fluidity or to improve the solidity of the castings, or to refine their grain. These important matters have been considered in detail by Pilling and Kihlgrenl and by numerous other workers cited by them, and with the exception of the first will not be considered in the present communication. The possibility of reducing the cost of bronze by replacing a portion of the tin with nickel received attention some years ago by Burgess and Woodward12 and, as will be shown later, offers attractive savings in cost under present conditions. The age-hardening characteristics of the nickel bronzes of appropriate compositions have been known for some time and were mentioned by Price, Grant and Phillips3 and discussed by Wise4 in connection with their paper. These matters are further considered in recent patents15 and are becoming of commercial importance in the production of high-strength castings. The equilibrium relations existing in the high-copper region of the copper-nickel-tin system have been carefully studied by Eash and Upthegrove,6 and in somewhat less detail by Veszelka.7 The observa-

Jan 1, 1934

"It shall be within the discretion of the Board of Directors to establish a medal to be known as the Charles F. Rand Memorial Medal to be awarded at such a time 'and under such rules as may be determined by the Board of Directors, for Distinguished Achievement in Mining Administration." The establishment of this medal was announced at the annual meeting in February, 1932, the term "mining" being defined in its broad sense to include metallurgy and petroleum. The members of the Charles F. Rand Foundation Award Committee, of which J. V. W. Reynders is Chairman, are listed on page 12. In both 1938 and 1939, the Committee gave consideration to the question of choosing a medalist but in each year the decision was reached to give financial help to other projects as an alternative. In 1938, publication of a monograph on "Struc¬ture of Ore Deposits in the Continen¬tal Framework" and of a booklet en¬titled "The Call for Endowment" was financed; and in 1939, a special appro¬priation was made to defray the ex¬ penses of special speakers for Affiliated Student Societies of the Institute. In 1940, the Committee elected to nominate a candidate for the medal and unanimously selected Robert, Crooks Stanley, Chairman of the Board of the International Nickel Co. This recom¬mendation was approved by the Board of Directors and Mr. Stanley became the first recipient of the medal. Citation for Award to Robert Crook,, Stanley. "For His Pioneering Leadership During a Period of Active Growth and Development of a World-wide Enterprise Involving the Mining of Nickel Ores, the Metallurgical Treatment Thereof, and the Expansion and Diversification of World Markets for Nickel Products. "For His- Able Direction of the Corporation Encompassing These Activities, Which Has Established an Enviable Record in Its Relations With Employees. Stockholders and With the Public."

Jan 1, 1941

By William P. Blake

It is scarcely necessary to point out the important functions of water in the mining operations of man, especially in the State of California, where sluicing and hydraulic mining have been practiced on such a grand scale as to arouse the opposition of the agricultural interests. But the role which water and ice have played in mining or excavating on their own account is not so apparent. The alluvions of existing rivers, and the higher gravel-beds left by ancient streams, are doubtless the result of running water; but how far these gravelly materials owe their origin primarily as rocky debris and fragments of veins to glacial erosion, it is difficult .to determine. Yet we see on every side in our higher mountains unmistakable evidences of the cutting, crushing and eroding effects of glacial ice. We note that mountain-summits have been reduced in height and shaped into rounded and dome-like summits. We know that the general contour of the hills of New England, of the Highlands of the Hudson, and of the mountains of northern New Jersey, is due to glacial carving. The same is true of the Laurentian hills of Canada and of the mountains of all northern regions. And we recognize in the vast deposits of so-called " drift," which are spread out over the surface of the northern States, the chips and debris from the glacial workshops. Thus we cannot avoid the conclusion that there was an enormous amount of cutting and excavating in glacial times, and that vast quantities of veinmaterial and of ores and metals must have been liberated by ice-action.

Jan 1, 1900

By H. D. Hoskold

It was not for the purpose of asserting any superior knowledge or authority, but simply of clearing up, in greater detail, some points casually mentioned in Mr. Scott's able paper, that the writer entered, some two years ago, into the discussion which that paper initiated. In such matters there is always room for differences of judgment, as well as for additional data, which may modify or complete the conclusions even of the best authorities. Those who are immersed in the duties of practical administration or work in the field, and who, being remote from the great scientific national libraries, are obliged to rely on their private collections, and to supplement them by their recollections of earlier studies, labor under special disadvantages in such a discussion; and it must be to the scientific and engineering world a matter for gratitude that Mr. Lyman has been willing to give the benefit of his advantages in this respect. Mr. Lyman would, however, doubtless at once disclaim the conclusion that his masterly summary constitutes " the last word " on this subject, and welcome further evidence, comment and criticism, such as the various contributors may continue to offer. This, therefore, is the motive, and must be the excuse, of the introduction by the writer of the following observations. The Miners' Dial.—Many years since, the writer employed a miners' dial, older in type than Fig. 12,* but without any attached spirit-level, made by Thomas Jones, a pupil of the great Ramsden. Jones was one of the old London makers and opticians, and enjoyed great reputation for accuracy in the con-

Jan 1, 1902

By Hugh S. Spence

THE use of natural feldspathic rocks, as opposed to straight feldspar, for ceramic purposes is not new. "Cornwall stone," a semi-kaolinized granite containing fluorite, has long been used by the English pottery trade instead of feldspar, and "Carolina stone," a similar rock, is now being offered to the American trade. A recent report of the U. S. Bureau of Mines states that trachyte, a glassy volcanic rock, is being used in California instead of feldspar in ceramic bodies. In Germany, phonolite and basalt have been investigated, and possibly also used, as ceramic raw materials, and extensive research has been conducted in Russia in recent years looking to the utilization of the immense bodies of nepheline syenite of the Kola Peninsula, which is the host rock of the apatite deposits now being exploited on a large scale in the Murmansk region; the nepheline is recovered as a by-product of the concentration of the apatite. Long used principally as a raw material for the pottery and allied industries, where, in bodies, glazes, enamels, etc., it serves as a fluxing ingredient and forms, on firing, a glassy bond with the more refractory clay, flint and coloring particles, feldspar has been finding ever increasing employment in glass. In 1936, over half of the nearly quarter of a million tons of feldspar sold in the United States went to the glass trade. Its usefulness for this purpose is due to the resistance to thermal shock which it imparts to glass products, particularly bottles, containers and tableware, because of its alumina content, which averages from 16 to 20 per cent. Active search has been made on the American continent during the past few years for other minerals of feldspathoid type, with comparable or higher alumina content, that may be suitable for glass and other ceramic purposes. One of the most important results of this work has been the delimiting in central Ontario of large bodies of nepheline syenite of excellent ceramic grade.

Jan 1, 1938

By D. K. Crampton

The object of this work was to obtain and correlate information on effect of internal stress in variously drawn tubes on several properties. Also, a simple approximate method of comparing types of stress distribution in such variously drawn tubes was sought. There is also included some work on comparison of single and polycrystalline materials and effect of different types of operation and preferred orientation. Preparation of Material A series of tubes was drawn to study the effect of the type and degree of final reduction on various physical properties and the approximate distribution of stress intensity across the tube wall. The material used all came from a single heat of 70-30 brass melted in a regular production Ajax-Wyatt induction furnace. The analysis of the metal as cast was: copper, 70.36 per cent; lead, 0.04; iron, 0.02; zinc, balance. The material was cast in "shells" with 4 in. outside diameter and in. wall thickness. It was drawn part way down according to the usual standard mill schedule and then by suitable individual schedules to finish by a variety of types and degrees of drawing to the same final cases in every instance; namely, 0.750 in. outside diameter by 0.080 in. wall thickness. The exact final draws, together with the percentage area reductions, diameter reductions and gage reductions are given in Table 1. In fabricating these tubes, rather unusual precautions were observed to insure the elimination of ail variables not under immediate study. All intermediate anneals were carried out at about 1200" F. down to the so-called "cut-in size"; namely, 17/16 by 3/16 in. From this point on, all anneals were made at from 1050' to 1100" F. The greatest care was used all through to have the tubes as free from minor surface defects as possible. When such defects were visible on intermediate sizes they were carefully filed out. On the final draw to 3/4-in diameter the die was aligned with the greatest possible precision in order to insure as straight a tube as possible

Jan 1, 1933

By L. J. Murphy

The production of crude oil in the United States is exceeding consumption by one-quarter million barrels per day and, with the possibilities of West Texas, this condition of overproduction, unless controlled, is likely to continue for some time. The resulting low price of oil has caused the operator to observe closely his lease operating costs. The installation of more efficient and reliable machinery has followed and it can well be said that the art of producing oil is on the threshold of a new era. In this advancement electricity has played a leading part. This paper covers only the problem of electricity as applied to lease operation and does not consider other phases of the industry, such as drilling and pipe-line pumping, in which electric power has been utilized economically. In considering electrification of pumping wells, the first question the operator asks is whether or not his costs will be reduced and the second question is whether or not the production will be increased. The third question, although in effect it is closely allied to the first, is the cost of power. The last question can be answered only after a thorough analysis of operating conditions and a study of the power rates prevailing in the particular field under consideration. Within the past few years, the power companies have realized the desirability of a steady 24-hr, pumping load, have made their rates for oil-field service particularly attractive, and in general have shown splendid cooperation in assisting the oil companies in the satisfactory application of electric power to their leases. When everything is taken into consideration, the first cost is practically the same for electric drive as for gas engines when pumping on the beam with individual motors. This cost, at prevailing prices, should aver-age approximately $2200 to $2400 per installation when using 15 to 35-hp., two-speed pumping equipment, including motor and control, countershaft, motor house, belt, installation charges, and a prorated portion of the cost of transmission lines and transformers for serving a number of wells. Since there is practically no difference in the cost of the two installations, it is evident that electricity, to justify its consideration, must have a lower operating cost or produce more oil.

Jan 1, 1928

By Howard L. Hartman

There is reason to believe that ventilation systems so far devised for use with continuous mining machines fall far short of success. This is vividly demonstrated to anyone who has observed in a continuous miner section the localized ignitions of pockets of gas and the generation of dense clouds of dust by the cutting head of the machine. The alarming frequency with which major ignitions and disasters continue to occur in modern mechanical mining and the rise in incidence of pneumoconiosis serve as reminders that our ventilation systems are far from achieving the ultimate in providing protection from either short-term explosions or long- term dust diseases, both of which take lives. Human safety is the main concern in ventilation. But in this day of high-priced labor, let us not forget human comfort, either, for this is a major factor in motivation toward high productivity. The failure or inadequacy of most mine ventilation systems in providing the kind of working conditions at the face that are conducive to productive as well as safe operation is an indictment of our environ- mental control program in mining generally.

Jan 3, 1962

By J. D. Miller, M. Misra

The processing strategy for the effective separation of bitumen from low grade (<l0 weight percent bitumen) Utah tar sands by a hot water process differs significantly from that used for the processing of high grade (> 10 weight percent bitumen) Utah tar sands. Excellent separations (coefficient of separation = 0.9) can be achieved for high grade Utah tar sands by intense hot water digestion followed by a modified froth flotation step. Such a technique is ineffective for low grade tar sands. In order to change the characteristics of the low grade tar sand an attempt was made to enrich the bitumen content of the feed to greater than 10 weight percent by recycle of bitumen concentrate to the digestion stage. However, the quality of the separation was not improved under these circumstances. Similarly feed enrichment by heat treating the low grade feed with recycled concentrate prior to digestion did not improve the separation. More successful separations of low grade Utah tar sands were finally achieved by modification of the viscosity of the low grade bitumen with controlled addition of diluent. These results of the hot water separation tests and variations in the quality of separation are interpreted in terms of the physical properties of the bitumen and the surface bonding forces operative at the bitumen-sand interface.

Jan 1, 1981

By Robert S. Dalzell, Ernest A. Curth

Following the introduction of shields to the U.S. longwall mining scene and the steady increase in the number of shield faces during recent years, the occurrence of longwall -ground-control -associated accidents has shown a welcome downward trend. But even though the accident experience is favorable, problems exist. New mining systems, however efficient, have run afoul of roof control. Shield faces have suffered extended stoppages because of roof cavities. Therefore, the Bureau of Mines has reviewed foreign remedial techniques to evaluate their potential for domestic application. Such technology includes cribbing, strain absorbent modules (SAM&apos;S), inflatables, wire meshing, chemical rock stabilization, synthetic foams, and monolithic fills.

Jan 1, 1984

By Will H. Coghill, Fred D. DeVaney

THE coercimeter, as its name implies, is an instrument for measuring the coercive force[+] of magnetic substances. It was developed by Davis and Hartenheim in the Special Studies Section, Metallurgical Division. A detailed description of this apparatus may be found elsewhere.2 The coercive force determinations of magnetic materials are interesting because of the relationship established by Gottschalk,4 who showed a linear relationship between the magnetization coercive force and the specific surface of comminuted particles. The value of this relationship in determining grinding efficiency has been shown by Dean.3 The determination of the surface contained in the subsieve sizes has always been a difficult problem for investigators. They made approximate measurements of the surface of coarse materials by sizing on screens, but for the determination of the surface of the sub- sieve sizes it was necessary to make detailed grain counts or elutriation tests, or to study dissolution rates. The technical literature contains many references to other methods for determining these surfaces, either by some special apparatus or by mathematical calculations based on distribution lines. Many of the methods are long and tedious, and the results of some, at least, are questionable. The turbidimeter gives quick results on ground cement. By using magnetite as the material to be ground, a simple determination of its coercive force by the coercimeter, requiring 10 minutes or less, can be transposed directly and accurately into units of relative surface. This subject has been pursued further by the U. S. Bureau of Mines in cooperation with the Missouri School of Mines and Metallurgy, Rolla, Mo., and the following is a description of the results.

Jan 1, 1938

By T. M. Berry

FOR the past several years it has been growing practice to install circular shafts at deep mining operations. Several factors have brought this about. Throughout eastern and midwestern coal fields circular shafts have been conventional for many years. Where large bodies of coal are mined, a production shaft may have a life of 20 to 30 years. Quantity production is essential; therefore the shaft must have a large cross-sectional area for larger skips and cages. Mechanical mining has become a necessity if a company is to stay in business today. Continuous mining machines and cutting, loading, and hauling equipment must be taken in and out of the mines. If the access shaft is not large enough there will be expensive dismantling and assembling. This has become a problem at many operations, particularly in the western sections where ore was originally mucked by hand into small cars and hoisted by a skip through a narrow rectangular shaft having small compartments. Mechanical loaders must be dismantled to wheelbarrow size to go into these mines.

Jan 7, 1957

By Arthur Wilson, Frederick Carr

INTRODUCTION 1. The application of retreat longwall mining to the North American coal mining conditions is becoming more advantageous as more experience is gained. The productivity results being achieved and potential possible illustrates that this system can be keystone of future underground coal production. 2. In the American coal fields multi-entry is normally practiced as this allows profitable longwall development with existing equipment and systems. Difficulties are being experienced however in the longwall retreat phase by the collapse of multi-entry roadways and excessive use of supplemental support in the following panel tailgates. In some instances the headgate of an operating face can also be in difficulty. 3. Jim Walter Resources Mining Division is developed on a mining plan that calls for three retreat longwalls at each of its four deep mines which have varying depths of cover and immediate roof and floor conditions. The 63 Mine has experienced longwall entry difficulty and there were differing viewpoints with respect to the best development systems to adopt particularily regarding the number of entries and pillar sizes. In an attempt to reconcile these different points of view J.W.R. asked Dr. Wilson to examine the problem and this paper outlines the new approach developed.

Jan 1, 1983

By W. H. Emmons

A DIATREME is a hole blown through a rock by gases, presumably of volcanic origin. Not all pipes of ore have formed by deposition of metals in such openings, but a con-siderable number have so formed. In this paper are described peculiar vein patterns that are believed to be incipient diatremes or "perforation pipes." Grading into this group is one showing thorough brecciation without rotation of fragments and into the latter a group of ore pipes showing brecciation with rotation of fragments-many of them with well rounded fragments. Also, volcanic craters or volcanic necks are explosion pipes. These may carry ore deposits along their contacts and some carry deposits within the pipes. As new data appear this group becomes increasingly impressive. It has been shown that veins are concentrated in and about cupolas of batholiths and that such veins commonly lienearly parallel to the long axes of cupolas as these are shown on plans. It would be supposed that conical cupolas would have radial patterns, but few vein systems exhibit radial patterns. It is probable that explo-sion pipes also may form in areas above conical cupolas. From these the gases escape more violently because the loads above them are less than above an elongated cupola where larger bodies of rock are affected. The hypothesis is sound mechanically, for the top of an elongated cupola is a line whereas the top of a conical cupola is a point.

Jan 1, 1938

By Marvin P. Barnes

Definition The term mineral inventory is a relatively new designation, born of the computer age and grown to common usage with the development of computer techniques for extending drill-hole sample values to regularly gridded data blocks representing in situ mineral values. The term has been generally accepted by geologists and engineers because it has a precise meaning which avoids many of the ambiguities of ore reserve. A mineral inventory is an estimated inventory of mineral in place and is usually achieved by dividing the deposit into regularly spaced gridded blocks to which are assigned estimated values using various extension techniques. A mineral Inventory makes no presumptions about the minability of the blocks or their cutoff grade. A mineral inventory estimate may be good or poor according to how much is known about the deposit, how extensively it has been sampled, and what techniques have been employed to assign estimated grade to the blocks Such an inventory, however, does not change with time, economic conditions, or mining technology, but only with new and better data and methods. Thus, the mineral Inventory is an excellent designation for describing mineral value distributron within a deposit&apos;s geological setting

Jan 1, 1979

By E. C. Truesdale, Gerald Edmunds

A few years ago H. M. Cyr, working in the Research Laboratories of The New Jersey Zinc Co., produced a few pounds of zinc1 of such purity that no other elements were detected in it by spectrographic analysis, using the facilities then available. This zinc contained less than one ten-thousandth of one per cent of metallic impurities.&apos; During the decade that followed upon the laboratory production of this "spectro-graphically pure" zinc, commercial developments brought about the production of large tonnages of zinc of purity exceeding 99.99 per cent, and today zinc of 99.999 per cent purity is produced and marketed as "chemically pure" zinc. Typical analyses of present supplies of high-purity zinc are given in Table 1. Table 1.—Typical Analyses Percentnge by Weight Sum of Zinc Fe, Ib1 Fe Cd 1A1 cd Special High Grade*.......... 0.007b 0.005b 0.005b none O.OIOb C.P. (chemically pure)......... < 0.0002 0.0005c 0.000052 S.P. (spectrographically pure).. <0.0002d <0.00005d a A.S.T.M. Standard Specification for Special High Grade Slab Zinc (A.S.T.M. Designation: B 637). b Maximum. &apos; Fe chemically determined. Pb and Cd are spectrographically determined. d Differences between composition of C.P. and S.P. zinc are discussed later in this paper. The availability of commercial tonnages of special high-grade zinc has been the basis for the development of the zinc-base die-casting alloy industry which, in the year 1936, consumed one-eighth of the zinc used in the United States for all purposes. This and the C.P. and S.P. grades have given impetus to scientific investigations into the properties of pure

Jan 1, 1939

By E. C. Truesdale, Gerald Edmunds

A few years ago H. M. Cyr, working in the Research Laboratories of The New Jersey Zinc Co., produced a few pounds of zinc1 of such purity that no other elements were detected in it by spectrographic analysis, using the facilities then available. This zinc contained less than one ten-thousandth of one per cent of metallic impurities.&apos; During the decade that followed upon the laboratory production of this "spectro-graphically pure" zinc, commercial developments brought about the production of large tonnages of zinc of purity exceeding 99.99 per cent, and today zinc of 99.999 per cent purity is produced and marketed as "chemically pure" zinc. Typical analyses of present supplies of high-purity zinc are given in Table 1. Table 1.—Typical Analyses Percentnge by Weight Sum of Zinc Fe, Ib1 Fe Cd 1A1 cd Special High Grade*.......... 0.007b 0.005b 0.005b none O.OIOb C.P. (chemically pure)......... < 0.0002 0.0005c 0.000052 S.P. (spectrographically pure).. <0.0002d <0.00005d a A.S.T.M. Standard Specification for Special High Grade Slab Zinc (A.S.T.M. Designation: B 637). b Maximum. &apos; Fe chemically determined. Pb and Cd are spectrographically determined. d Differences between composition of C.P. and S.P. zinc are discussed later in this paper. The availability of commercial tonnages of special high-grade zinc has been the basis for the development of the zinc-base die-casting alloy industry which, in the year 1936, consumed one-eighth of the zinc used in the United States for all purposes. This and the C.P. and S.P. grades have given impetus to scientific investigations into the properties of pure

Jan 1, 1939

By J. Peperakis

Coal mine bumps are normally associated with pillar mining under moderate or deep cover. Severe bumps at Sunnyside, however, have not been confined to pillar lines. Many have occurred in virgin development and in localities a long way from active pillar workings. As early as 1918 bumps in virgin territory were attributed to the faulted structure in the Sunnyside area.&apos; Sunnyside is an old property, mined for more than 60 years. Both man-made and natural conditions contribute greatly to bump occurrences, and loss of life and great destruction of workings have resulted from some unusual bumps in recent years. Before Kaiser Steel acquired the Sunnyside Mines in 1950, about 21 million tons of coal had been extracted. Large areas had been worked out and equally large areas first-mined. As demand for coking coal gradually diminished, extensive blocks were shut down, and during the low production period of the 1930&apos;s mining on a very limited scale was confined to a section of the property close to the coal tipple. Following purchase of the property Kaiser Steel developed the mines into a fully modernized operation. The worked out and first mined areas covered about four square miles extending five miles along the strike and up to one and a half miles down dip from the outcrop. The sections with favorable mining conditions and clean coal had been largely extracted under the selective mining system imposed by economic conditions and the lack of cleaning plant facilities. Large reserves remained on the fringes of the worked out sections and in areas under deep cover and difficult roof. There were also considerable reserves in first-mined areas. In recent years much of Sunnyside&apos;s daily output of 7000 to 8000 tons has been derived from the partially mined localities. Many bumps have occurred when pillars have been pulled within the first-mined areas and on the fringes. The bumps have been associated with retreating pillar lines backing up against old workings and pillar lines in old first-mined areas backing up against highly stressed oversized barrier pillars surrounded by smaller pillars. In some parts of the property the upper Sunnyside seam was extensively worked in the past, and sizable areas of old works overlie the present lower seam workings. Abutment pressures from barrier pillars and pillar remnants are transmitted to the lower seam, contributing to bumps and squeeze conditions. Cover: The terrain is exceedingly rough, and cover varies considerably over relatively short horizontal distances. For example, at No. 1 mine the 2000-ft cover line is ony 2700 ft from the coal outcrop, and at No. 2 mine the cover over the main hoisting slope increases from 1000 to 2000 ft in a horizontal span of 1200 ft. Cover over the present mining sections ranges from several hundred feet in the valleys to 2500 ft under the crest of the divides. A short distance ahead of Sunnyside&apos;s deepest development down dip the cover reaches 3000 ft or more.

Jan 1, 1959

By J. M. Stuart, G. D. Bengough, A. R. Lee

Corrosion tests should be designed so as to facilitate as far as possible the interpretation of results, consequently factors which may affect the rate of corrosion should be controlled as far as practicable, and very full data should be given regarding the conditions of the test. Among the most important factors affecting the rate of corrosion is often the rate of supply of oxygen to the metal surface. It is essential therefore to understand the mechanism by which oxygen is transferred from the liquid surface to the surface of the metal. The work of Adeney and his coworkers has thrown much light on this mechanism. They have shown1 that the aeration of deaerated water and salt solutions proceeds much more rapidly than can be accounted for by mere diffusion, and have suggested that downward "streaming" takes place from the surface of the water, due mainly to an increase of density brought about by evaporation. The evaporation reduces the temperature of the surface layer, and also increases the concentration in the case of salt solutions. The effect of evaporation in facilitating the transfer of oxygen to a metal and increasing the corrosion of the metal was shown in some experiments due to Friend.2 He tested the corrosion of mild steel plates immersed in water in glass jars, a steady stream of air being drawn over the surface of the water in the jars. The air passing through half the number of jars was saturated with moisture, that passing through the others was dried with calcium chloride. He found that "in every case the water exposed to dry air was approximately twice as corrosive as that exposed to air saturated with water vapor." Conditions for Quantitative Corrosion Tests These results show that we must either control or prevent evaporation at the liquid surface, if we wish to avoid effects on the rate of cor-

Jan 1, 1929

By K. B. Nowels

The attainment of efficient flooding to a large extent depends upon a knowledge of fluid movement through porous media and the pressures used in controlling this movement. Little has been understood con-cerning the fundamental principles involved in the forced drive of water-flooding and an attempt will be made to present some data which may be of interest. Considerable data and technical information pertaining to natural and artificial water-flooding have been presented in the past by Torrey, Umpleby, Fettke, Panyity and others. Their papers have thoroughly covered the description of past and present-day methods of oil recovery by flooding in the Bradford field, especially an article by Torreyl in the Petroleum Engineering Handbook. A bibliography of papers devoted to watcr-flooding, published in Mr. Torrey&apos;s article, is appended to this paper. No attempt has been made, therefore, to describe the installations and procedure necessary in flooding, thus permitting the writer to deal exclusively with the mechanics of water movement in flooding operations and its relationship to well spacing. Artificial water-flooding will probably always be the most successful in oil fields described by Herold as being under "capillary control"" and will probably be useless in fields naturally under hydraulic or volumetric control. The natural water drive in an oil field under either of these two controls may give efficient recoveries, as a result of the regulated encroachment of edge water. Such a "natural flood" resulting from the influence of edge water must not be confused with the term as used in this paper, however. Any reference to "natural flood" will here refer to the old method of flooding formerly used in the Bradford field. This was discovered largely by accident and utilized the hydrostatic pressure created by a column of water standing in a watered-out oil well in forcing the oil to an adjacent producing well. The same principles are involved in either natural or artificial flooding, and the latter method simply

Jan 1, 1933