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By E. J. Duggan

It is a coincidence that the two plants in this country for treating copper ores by ammonia leaching came into existence at almost the same time, that of the Kennecott Copper Corporation at Kennecott, Alaska, in March, 1916, and that of the Calumet & Hecla Mining Co. in July of the same year. The success of both from their very beginning attests the merits of the process under widely different sets of conditions. As would be expected, in the time they have been operating these two pioneers in this field have greatly perfected their methods and improved their technic. The early difficulties inevitably encountered in undertakings of this nature have been largely surmounted and the process may now be considered to be well seasoned and matured. There have been no other commercial plants built in this country and but one elsewhere, the Bwana M'Kubwa in Northern Rhodesia, for the reason that this method of treatment may be employed on comparatively few ores. However, it has certain advantages, some of which are inherent to sand leaching processes generally and some to ammonia leaching in particular. Among these may be enumerated: (1) the avoidance of fine grinding; (2) the small amount of water required; (4) a high-grade product; (5) little likelihood of deleterious gangue constituents and fouling of solutions. It is true that great progress has been made in recent years in the flotation of the ores that come within the province of ammonia leaching. Nevertheless ammonia leaching has its possibilities and these may be overlooked in the present tendency toward the use of flotation for all ores. Probably the chief requisite to its further extension to suitable ores will be a cheap source of steam. Ammonia, the only reagent required, is unlimited in supply, readily transported and the price that is likely to obtain in the future should not make its cost at all onerous. Choice of Method for Kennecott Ores The Kennecott ores are typical limestone replacement deposits. The milling ores have a copper content of approximately 8 per cent in a limestone dolomite gangue. About half the copper occurs as sulfide, mostly chalcocite with some covellite, and the remainder in the form of the two carbonates, malachite and azurite. A comparatively coarse grind followed

Jan 1, 1934

By O. P. Quist, S. H. Carpenter

The internal friction of single-crystal LiF has been investigated as a function of crystal orientation, while simultaneously applying a static compressive load. Three different crystal orientations were used, these being samples with the (100), (110), and (111) directions along the sample length. Results show the internal friction measured to be similar in appearance but different in magnitude for the (100) and (110) samples. With both orientations, application of a static stress caused an increase in the amplitude-independent damping, which recovered with time. The amplitude-dependent damping was found to first decrease with load up to the yield stress and then increase rapidly. Samples of the (111) orientation were found to have no measurable internal friction even when loaded up to 3.0 kg per sq mm. These results are discussed in terms of current theories of internal friction in ionic crystals. This paper presents the results of an investigation of the dislocation mobility and dislocation motion in high-purity single-crystal LiF at applied stress levels up to the yield stress. Internal friction measurements of the dislocation damping while simultaneously applying a static compressive load was the experimental technique used. LiF crystals much prefer to slip on the (110) set of slip planes. However, with a suitable stress distribution they can be forced to slip on the {100} set of slip planes.' For both sets of slip planes the slip direction is the same, namely (110). The object of this investigation was to try and learn more about the dynamical properties of dislocations on the different slip systems in LiF crystals. EXPERIMENTAL PROCEDURE Dislocation damping was measured, in terms of the log decrement, using a five-component marx2 composite piezoelectric oscillator. The apparatus used allows one to measure the dislocation damping while simultaneously applying a static compressive load on the sample. A schematic of the apparatus used is shown in Fig. 1 and a complete discussion of its construction and operation is given elsewhere.3 All measurements were made at room temperature with a longitudinal resonant frequency of approximately 50 kc per sec. Damping measurements were made using longitudinal vibrations with strain amplitudes from up to 10. Static loads up to 3.0 kg per sq mm were applied to the sample while the damping was being measured. Samples used in this investigation were high-purity single crystals of LiF purchased from the Harshaw Chemical Co. All samples were approximately of an in. square and were hand-ground in length to one-half wavelength to match the resonant frequency of the driver and gage quartz crystals. Samples of three different crystallographic orientations were used, namely, crystals with the (loo), (110), and (111) direction parallel to their length. The magnitude of the damping is a direct measure of the area on the slip planes swept out by dislocations during a complete oscillatory cycle. With a sample of the (100) orientation the maximum applied shear stress, due to longitudinal vibrations, is on the (110) slip planes with zero shear stress on the (100) slip planes. Thus, damping measured from a (100) sample is due entirely to dislocation motion taking place on the (110) set of slip planes. Similarly, for a sample of the (111) orientation there is zero shear stress on the (110) set of slip planes and the damping measured from a sample of this orientation is due entirely to dislocation motion on the (100) set of slip planes. Samples of the (110) orientation will have a component of shear stress on both sets of slip planes and

Jan 1, 1969

By T. R. Graham, J. R. Long

This report is concerned with part of a series of investigations carried on by the Federal Bureau of Mines on alloys, particularly nonferrous alloys, made with electrolytic manganese. A broad general program instituted after commercial quantities of electrolytic manganese became available was necessary in order to compare the effects of electrolytic manganese with those of the ordinary commercial grades. Representative analyses of these two materials show the commercial manganese metal to contain up to 2 per cent iron, a maximum of I per cent silicon and 0.06 per cent carbon, while the electrolytic manganese rarely exceeds 0.01 iron, 0.02 sulphur, with no silicon or aluminum. In the literature, the emphasis has been largely on high-strength casting alloys containing up to 5 per cent manganese, and few data are available on wrought manganese alloys. These factors, coupled with the strategic position of copper and zinc, have given impetus to the Bureau's War Research Program for the development of alloys containing nonstrategic manganese for the purpose of supplementing or providing alternates for the more strategic metals. The alloy reported here was studied, along with several other ferrous and nonferrous alloys, as possible cartridge-case material, and was chosen after a review of the properties of the ternary alloys of copper-manganese-zinc. Preliminary Work In a cursory survey of this system, alloys ranging from 60 to 95 per cent copper, o to 50 per cent manganese, and 5 to 40 per cent zinc were investigated. The alloys containing 60 per cent copper were found to fall into the two-phase alpha plus beta region of the system, and since those containing 70 per cent would not permit a saving, only alloys containing 65 per cent copper were considered. The tensile properties of these 65 per cent alloys are plotted in Fig. I as a function of manganese content for annealed material and for four conditions of cold-work In the annealed condition the increases in strength and decreases in elongation are minor up to 15 per cent manganese; beyond this, the changes become more significant. In the cold-worked condition, the first 5 to 10 per cent of manganese appears to have the greatest strengthening effect, the rate of increase dropping off as the manganese increases beyond this amount. These effects are more pronounced with moderate than with severe cold reduction. It is also interesting to note that while the elongation of annealed material drops regularly with increasing manganese, the elongation in the cold-worked state is relatively little affected by increasing manganese content, particu-

Jan 1, 1944

By J. R. Long, T. R. Graham

This report is concerned with part of a series of investigations carried on by the Federal Bureau of Mines on alloys, particularly nonferrous alloys, made with electrolytic manganese. A broad general program instituted after commercial quantities of electrolytic manganese became available was necessary in order to compare the effects of electrolytic manganese with those of the ordinary commercial grades. Representative analyses of these two materials show the commercial manganese metal to contain up to 2 per cent iron, a maximum of I per cent silicon and 0.06 per cent carbon, while the electrolytic manganese rarely exceeds 0.01 iron, 0.02 sulphur, with no silicon or aluminum. In the literature, the emphasis has been largely on high-strength casting alloys containing up to 5 per cent manganese, and few data are available on wrought manganese alloys. These factors, coupled with the strategic position of copper and zinc, have given impetus to the Bureau's War Research Program for the development of alloys containing nonstrategic manganese for the purpose of supplementing or providing alternates for the more strategic metals. The alloy reported here was studied, along with several other ferrous and nonferrous alloys, as possible cartridge-case material, and was chosen after a review of the properties of the ternary alloys of copper-manganese-zinc. Preliminary Work In a cursory survey of this system, alloys ranging from 60 to 95 per cent copper, o to 50 per cent manganese, and 5 to 40 per cent zinc were investigated. The alloys containing 60 per cent copper were found to fall into the two-phase alpha plus beta region of the system, and since those containing 70 per cent would not permit a saving, only alloys containing 65 per cent copper were considered. The tensile properties of these 65 per cent alloys are plotted in Fig. I as a function of manganese content for annealed material and for four conditions of cold-work In the annealed condition the increases in strength and decreases in elongation are minor up to 15 per cent manganese; beyond this, the changes become more significant. In the cold-worked condition, the first 5 to 10 per cent of manganese appears to have the greatest strengthening effect, the rate of increase dropping off as the manganese increases beyond this amount. These effects are more pronounced with moderate than with severe cold reduction. It is also interesting to note that while the elongation of annealed material drops regularly with increasing manganese, the elongation in the cold-worked state is relatively little affected by increasing manganese content, particu-

Jan 1, 1944

By J. E. Pavlick, W. W. Mullins, H. W. Paxton

The growth of nitrogen-austenite during nitriding of large-gvained ferrite between 650" and 800°C has been studied as a functimz oJ time and nitrogen potential of the atmosphere for a variety of alloying elements dissolved in the ferrite. Whereas no preferential grain boundary penetration by aistenite takes place in zone-refined iron, the addition of aboit I zot pct oj' V, Ti, Cr. Si, or A1 produces significant protrusion of austenite down former 0-0 boundaries. This group of elernents also produces ragged y-0 interfaces in the a grains which advance more slozuly than those in zone-refined iron. 1 zut pct of Ni, Co, Mn, or Mo dissolved in ferrite leads to essentially smooth 7-a interfaces, which advance at rates very sinzilar to those in zone-refined iron. The reasons for this effect are not clear. Two possible limiting hypotheses, not necessarily exclusive, are discussed. One involves p.referentia1 grain bozindary diffusion of nitrogen. the other the production of a zone of ferrite, stpersatcirated with respect to nitrogen, from which austenite precipitates helerogeneozisly on the a-a gyain boundaries. In many phase transformations which occur by nu-cleation and diffusion-controlled growth, information on the parameters which control the rates of nuclea-tion and of growth is frequently not quantititative. The present work describes a continuation of efforts to obtain quantitative data on growth rates in systems where thermodynamic and kinetic factors are known independently, and thus where comparison with models of the growth process is possible. The work has been conducted on iron-base systems for two reasons. Firstly, there are several interesting transformations in this system, many of which are of practical importance. Secondly, the information on phase diagrams, activities, and diffusion coefficients is more complete in this system than in any other. These data are still inadequate to check all the effects of alloying elements, but at worst it is possible to make estimates and thus examine order-of-magni-tude agreement with proposed models. It will be necessary to do this in the present work. The problem studied was the growth of nitrogen-austenite in from the surface of large-grained columnar crystals of alloyed ferrite exposed to an NHs/Hz atmosphere. Earlier work by Grozier et al.' had suggested that growth of austenite may occur preferentially along grain boundaries of alloyed ferrite, whereas zone-refined (ZR) iron shows no such effect, Fig. 1. Growth of nitrogen-austenite into single crystals of zone-refined ferrite is planar provided sufficient nu-cleation sites for austenite are present, and is controlled by volume diffusion of nitrogen through the

Jan 1, 1967

By H. R. Banks

THE Sullivan concentrator has completed 20 years of operation. During this period a considerable amount of data has been accumulated concerning the characteristics of several types of flotation machines in their application to the problem of the differential separation of the lead sulphide, zinc sulphide and, in more recent times, iron sulphide, in the ore from the Sullivan mine. It is the author's intention to sketch briefly experiences encountered when the several types of flotation machines were introduced into the flow. ORIGINAL FLOTATION EQUIPMENT AND ORE The original flotation equipment consisted of four 18-cell lead-roughing machines, whose concentrate was cleaned in an 8-cell and recleaned in a similar 8-cell machine. Zinc concentration was carried out in four 18-cell machines. One 8-cell zinc re-treatment machine received the reground zinc middling. The 168 cells handled some 3000 tons of original daily feed. These cells were of the standard Minerals Separation type, equipped with 24-in. impellers. Spindles were driven through geared line shaft at a speed of 255 r.p.m. The impellers were the 45° type, except for the last three cells of the zinc-rougher machines, which were of sub-aeration type, with full bottom shroud and half shroud for the top side of the impellers. Four-pound air was introduced. This recognition of the benefit of intensified flotation operation for "gleaning" was an important phase in the early operation and will be discussed further on in this paper. Sullivan ore during this period is described as a finely disseminated mixture of four sulphides, totaling 90 per cent made up of 13.6 per cent galena, 14.4 per cent marmatite, 1 per cent pyrite and 61 per cent pyrrhotite. The specific gravity of the ore was approximately 4.4. There has been a gradual change in the ore content. The 10 per cent of nonsulphide constituents has increased to between 15 and 20 per cent and all three sulphides have dropped somewhat. Added equipment and changing technique have made possible the treatment of 8000 tons per day of mill feed instead of the 3000 originally handled. SPECIAL FEATURES OF FLOTATION AT SULLIVAN Sullivan flotation differs greatly from customary practice. The very heavy return of lead rougher middling and lead cleaner tailing, totaling at times 125 per cent of the new feed tonnage, has been the subject of much investigation. The practice is still employed.

Jan 1, 1944

By John Shelton

ONE of the heaviest burdens uselessly cast by our mineral land laws upon the holder of the title conveyed by a patent from the United States is due to the provision excepting known veins from land patented as placer. In many instances the expense of defending such titles from the assaults of the owners of lode locations made upon the theory that the veins so located were known to exist at the date of the placer application for patent has exceeded many times the value of the land in question. Neither the lapse of time, however long after the issuance of the patent nor repeated adjudications by the courts serve to quiet such titles or to prevent them from being questioned. In the passage of laws providing for the acquisition of title to the mineral lands of the United States, Congress provided that the title to known veins should not pass from the United States by a patent based upon a placer location. As construed by the courts, the law (Sec. 2333 R.S.U.S.) provides that the applicant for a patent upon a placer claim may, if any vein of sufficient value to justify the expenditure of money in its development is known by him to exist within the boundaries thereof, include in his patent application an application for patent upon the vein as a lode claim; and failure to do so is to be deemed a conclusive declaration that the applicant makes no claim to the vein nor to an area of surface ground extending for 25 ft. (7.6 m.) on each side of its middle or center. As to such vein and, such area of enclosing surface ground under the circumstances stated, the title remains in, the United States notwithstanding the issuance of a patent that purports to convey the entire surface of a described area and everything beneath it, excepting only the segments of veins the apices of which lie outside of such area. Such known veins with such area of enclosing surface ground are, of course, at any time, so long as they remain unlocated, subject to location and appropriation in the same manner as other veins upon the public domain. The history of the operation of this law in one district will serve to illustrate its effect generally throughout the mining regions of the United States. In the Butte district, the mineral that first attracted the atten-

Jan 8, 1919

By R. W. Raymond

THE Brüclrner roasting-cylinder is well known as an apparatus which has done good work in the desulphnrization, particularly of refractory silver ores, in the western districts of this country. A paper by Mr. J. M. Locke, of Cincinnati, describing the cylinders, as constructed by Messrs. Lane & Bodley, in that city, may be found at p. 295, vol. ii., of the Transactions of the Institute; and a paper by Mr. N. H. Cone, vol. iv., p. 226, gives an account of their operation in Colorado. The purpose of the present paper is to present an .improved construction, designed by Mr. Brückner. This is clearly shown in the accompanying plate, which scarcely needs explanation. It will be seen at once that this construction involves two cylinders, instead of one. Mr. Brückner thinks that three cylinders might be better yet, as securing an exact mechanical reproduction of the work of the well-known three-hearth Fortschaufelungsofen, the most perfect of the reverberatories in which delicate roasting is performed with hand-labor. THE APPARATUS. Erection of the Cylinders.—Although the cylinders may he put lip at any locality, or added to existing works, it is preferable, if possible, to choose the site on a hill sloping naturally, say about 30' or 33. Two excavations are made, one 8 to 12 feet higher up than the other; and each is protected by a wall with a batter of about 1 inch to the foot, to prevent slides of stone and earth. Each cylinder being 20 feet long and 7 feet in diameter, the total excavation should be 60 to 70 feet along the hill, and 15 to 25 feet wide. On each level a building is erected 35 feet long by 20 feet wide and 12 feet high, with the roof containing a ventilator against the hill. When both buildings are on the same level, there should preferably be a solid frame-work of very heavy timber, to carry the four rollers which bear the upper cylinder. The four rollers carrying the lower cylinder should preferably rest on two very heavy pieces of timber, strongly braced together and laid to their top in a foundation made of stone or brick and cement. Foundations are necessary only under each two opposite rollers, but they must be made carefully,

Jan 1, 1886

By Cyril Smith

ALTHOUGH alloys of copper and silicon were examined several years ago,1 and their excellent mechanical properties were shown, it was not until C: B. Jacobs2 introduced manganese in small quantities to the alloys that they became of commercial importance. A few years ago The American Brass. Company took over the patents and commenced to manufacture the alloy under the name "Everdur." The present study of the constitution of the ternary system was undertaken in order to reach a fuller understanding of the behavior of the alloy. REVIEW OF PREVIOUS WORK ON, THE BINARY SYSTEMS There have been no papers published dealing with the constitution of the ternary system, although some tests of the mechanical properties have been described,3 which indicate that there is a change insolubility with temperature.

Jan 1, 1930

By R. E. Pollard

The National Bureau of Standards received, in August 1940, a number of samples of bridge wire taken from the cables of the General U. S. Grant suspension bridge over the Ohio River at Ports- mouth, Ohio. These cables were 7% in. in diameter under the wrapping and each was made up of 1458 ungalvanized wires of No. 8 gage in 3 parallel-wire strands. The choice of ungalvanized wire was based on the previous satisfactory performance of similar wires in other bridges over periods of 20 to 50 yr. of service(1).2 After about 12 yr. of service a number of breaks were discovered in the Portsmouth bridge cables, most of them at the anchor- age shoes, and they were replaced by cables made up of galvanized wire(2).

Jan 1, 1945

By J. L. Gillson

IN a brief summary of the many occurrences of fluorspar in our western states, it is not possible to go into detail in regard to the geology, mining and milling methods, and reserves about individual deposits. Rather a broad review is made of the occurrences and an analysis of how the western deposits may fit into our future domestic economy is presented. GENERAL STATEMENT ON FLUORSPAR SITUATION Fluorspar has been used for years as a flux in the manufacture of basic open-hearth steel, in foundry cupolas for melting pig iron, in the manufacture of opalescent glass and in the preparation of hydrofluoric acid. In 1880 the annual production of fluorspar in the United States was around 4000 tons per year. By 1900 it was up to 21,656 tons and between 1902 and 1908 it averaged about 40,000 tons annually. Prices were then so low, by present standards, that it seems impossible to believe now that mining could have been performed profitably at the price levels then prevailing. In 1890 fluorspar sold at the mines for $6.70 per ton, in I901 for $5.81, in 1916 for $5.92. When the United States entered World War I, fluorspar production and price skyrocketed; the production reached 263,817 tons in 1918, with prices above $20.00 per ton, and prices were even higher in 1919 and 1920. After 1920, the domestic production fell from the 1918 level to about 125,000 tons annually and the average price dropped back to about $I8.00 per ton. By 1935 the average price had fallen to $15.00, but in 194o with a rising demand the average price of all grades had gone back up to $20.31. Today it is 75 per cent higher than in 1940 and presumably the price of acid grade at least would be even higher if it were not for price ceilings. The first subsequent year that the domestic production exceeded that of 1918 was 1941, and the 1944 production is expected to exceed 400,000 tons, 'or over one and a half times that of 1918. In five-year periods, average production and imports were as are shown in Table I. [ ] Many people concerned with the consumption of fluorspar believe that the postwar period ahead will show a repetition of price trends of the last such period. They believe that imports will be- again an important factor in the available supply and the price will fall back gradually toward the prewar level. The following basic factors are pertinent in analyzing this conclusion:

Jan 1, 1945

By Cyril Stanley Smith

IsolatEd alloys of copper and silicon were prepared and examined by chemical methods more than one hundred years ago, but it was not until the work of Rudolfi l that the equilibrium relations were studied. The early history of the alloys was well described by Baradue-Muller 2 and need not be further discussed here. The diagram of Rudolfi, based entirely on thermal observations, showed sillcon to be soluble in copper up to 4.5 per cent. at 849" C., at which temperature there was a peritectic horizontal resulting from the formation of a ß phase with about 7.4 per cent. silicon from a and liquid with 7.85 per cent. silicon. The ß phase was believed to form a eutectic with Cu3Si at 820" C. and 9.8 per

Jan 1, 1929

By Cyril Stanley Smith

IsolatEd alloys of copper and silicon were prepared and examined by chemical methods more than one hundred years ago, but it was not until the work of Rudolfi l that the equilibrium relations were studied. The early history of the alloys was well described by Baradue-Muller 2 and need not be further discussed here. The diagram of Rudolfi, based entirely on thermal observations, showed sillcon to be soluble in copper up to 4.5 per cent. at 849" C., at which temperature there was a peritectic horizontal resulting from the formation of a ß phase with about 7.4 per cent. silicon from a and liquid with 7.85 per cent. silicon. The ß phase was believed to form a eutectic with Cu3Si at 820" C. and 9.8 per

Jan 1, 1929

By D. C. Hilty, W. Crafts

The solubility of oxygen in iron containing aluminum has been determined at 1550°, 1600°, and 1650°C and found to be much higher than predicted from theoretical considerations, possibly due to equilibria with an iron-aluminum spinel phase rather than pure AI,O.. The presence of manganese greatly increased the deoxidizing power of aluminum. DEOXIDATION and inclusion formation in steel have proved to be elusive phenomena that are difficult to control in spite of much effort to understand and evaluate the reactions. Study of the problem indicated that more accurate data on the solubility of oxygen in iron containing deoxidizers were essential to further progress, and an empirical determination of oxygen solubilities has been initiated at the Union Carbide and Carbon Research Laboratories, Inc. The investigation has included the effects of aluminum, silicon, manganese, and combinations of these elements at 1550°, 1600°, and 1650°C. The equipment and experimental procedure as well as the results of a study of the effects of aluminum are described below. In general, it was found that the solubility of oxygen in iron containing aluminum is much higher than predicted, possibly because of the formation of complex nonmetallic phases, and that manganese greatly increases the deoxidizing power of aluminum. The generally accepted deoxidation curves for 1600°C are summarized in fig. 1, from "Basic Open Hearth Steelmaking"'. These curves are assumed to represent the solubility of oxygen in the presence of deoxidizers and should indicate the limits of mis-cibility gaps in the phase diagrams of the systems that control the formation and character of non-metallic inclusions as described by Benedicks and Lofquist'. They were derived mainly by application of the methods of thermodynamics to the available experimental observations, and by calculations based on the thermal constants of the pure substances when experimental data were lacking. Among the more notable researches contributing to the development of knowledge of oxygen solubilities are those of Korber and Oelsen8, 4, C. H. Herty, Jr. and associates5,6, Krings and Schackmann7, Went-rup and Hieber8 Schenck and Briiggeman9, Vacher and Hamilton'" and Chipman and co-authors 1,11,12,13 Practically, the deoxidation curves are of limited value in predicting oxygen content and rationalizing deoxidation practices. The reasons for this inadequacy appear to be error from inaccurate data, oversimplifying assumptions, interacting effects of combined deoxidizers, and possibly unknown extra-equilibrium and side reactions. Although inclusion formation is a very complex reaction it must be re-

Jan 1, 1951

By R. DiBella, H. Biloni, G. F. Bolling

A study of the detailed relationship between solidification substructure and microsegregation in dilute tin alloys has been continued. New observations reveal that depressions form at the solid-liquid interface not only as an initial form of segregation but throughout the range of increasing constitutional supercooling. In order to show the importance of this node formation it proves convenient to make two simplifications. Although substructure changes continuously as constitutional- supercooling increases,&apos; the following discrete stages may be used for discussion: 1) the planar solid-liquid interface; 2) ordered nodes, or depressions at the interface;&apos; 3) two-dimensional or elongated cells;3 4) regular or hexagonal cells;4 5) distorted cells, or hexagonal cells with branches;4 6) dendrites. It is also convenient to ignore observations made near grain boundaries which interact with the cellular substructure.2-4 And, it should be clearly pointed out that all singular depressions at the solid-liquid interface will be called nodes. Heretofore, the term "node" has been used without clear justification to describe both the truly isolated depression and the junction of cell walls appearing in a later stage of segregation. This usage is continued because it seems proved by the observations. Standard systematic growth of tin crystals was undertaken over a broad range of constitutional supercooling using various added solutes. Except for one or two chance observations, this research failed to reveal any appreciable range of growth conditions over which a disordered array of isolated nodes exists. Even though &apos;some finite range of random instability must exist, it is now concluded that stage one passes very rapidly to stage two. Next, after confirming that stage two passes to stage three by the elongation of isolated nodes: a reexamina-tion of stages three, four, and five followed. Standard metallography showed that pockets of higher solute concentration (for ko < 1) became more numerous in cell walls the more severe the growth conditions. These high-concentration regions must arise from depressions; however, in stage three their segregation is not distinguishable from the segregation of the nodes which join cell walls together. It seems, therefore, that the presence of nodes is causal in the formation of new cell walls, and that the mechanism by which stage three passes to stage four is initiated by nodes. If a similar reasoning is followed, the separation of stage four from stage five appears to be just a convenience that has arisen from the decanted interface observations made in the past. The present observations again show that more severe growth conditions relate directly to an increase in the number of nodes in the hexagonal cell walls. These nodes apparently serve as the origin for lines of segregation extending within the body of a cell, and can thus be assumed to represent the earliest form of branching,* as shown here in Fig. 1. The examination of stage six involved decanted-interface structures as in Fig. 2, which are similar to those considered by Rutter and Chalmers,5 Plaskett and winegard,6 and Hellawell and Herbert,7 and where distinct protrusions are each surrounded by a depressed boundary. The corresponding microsegregation behind the interface, but not far enough behind to allow a smearing of the segregation because of diffusion,4 is shown in Fig. 3. Both the shape of the decanted interface and the segregation pattern behind it

Jan 1, 1968

By Herbert Clark Hoover, Lou Henry Hoover

MANY persons hold the opinion that the metal industries are fortuitous and that the occupation is one of sordid toil, and altogether a kind of business requiring not so much skill as labour. But as for myself, when I reflect carefully upon its special points one by one, it appears to be far otherwise. For a miner must have the greatest skill in his work, that he may know first of all what mountain or hill, what valley or plain, can be prospected most profitably, or what he should leave alone ; moreover, he must understand the veins, stringers1 and seams in the rocks2. Then he must be thoroughly familiar with the many and varied species of earths, juices3, gems, stones, marbles, rocks, metals, and compounds4. He must also have a

Jan 1, 1950

By J. B. Scott, J. L. Popham, H. F. Coffer, J. J. Reynolds

This paper concerns field experiments to define the areal extent, orientation and thickness of an artificial fracture in the Sacatosa field, Maverick County, Tex. The fracture was made by a sand-oil treatment of 176,-000 gal of lease crude containing a fluid-loss additive and 270,000 lb of 20-40 mesh subangular Poteet sand. The well was perforated with a jet gun, consisting of six shots in a single plane. Fourteen test holes were drilled at various locations around the fractured well. Drill-stem tests, Micro and Sonic Logs, coring and sampling of formation cuttings were used to determine the presence of the fracture in these holes. The test holes were drilled at distances up to 250 ft in a radial pattern around the fractured well. In addition to fracture areal extent and orientation, sand grain size before and after fracturing, erosion of perforations and fracture thickness were studied. INTRODUCTION The orientation,12 areal extent3, 4 and thickness5-9 of artificially induced fractures in reservoir rock by hydraulic means have been discussed in great detail in the oil industry in recent years. Methods for initiating vertical"&apos; and horizontal" fractures have been tested in the laboratory and the field. Although the methods used give successful well stimulation, good field data on the physical characteristics of the fracture are lacking in the literature. It is recognized generally that properties of a fracture, such as thickness, sand placement in the fracture" and shape, may vary from reservoir to reservoir. This paper gives data on size, orientation and sand placement in a large fracture initiated in a single plane in Sacatosa field, Maverick County, Tex. It is not intended as a speculative study; rather, it is restricted to actual field data on fracture properties. No attempt is made to prove that the same type of fracture occurs in all wells. The field procedure was to drill 14 test holes at various locations around the fractured well. By employing several different testing techniques, the presence of the fracture and some of its characteristics were determined. These techniques as well as the results obtained are discussed in detail in this paper. DESCRIPTION OF FRACTURE TREATMENT N. J. Chittim Well No. 37-1, completed in the San Miguel No. 1 sand, Sacatosa field, Maverick County, Tex., was chosen for the field study. The San Miguel sand is a tight, well consolidated sandstone with an average porosity of 23 per cent. The permeability ranges from 0.1 to 10 md, with a median permeability of 2.3 md. The sand thickness averages 23 ft and is located at depths of 1,150 to 1,700 ft throughout the field.I3 The fracture treatment performed on Well 37-1 was as follows. 1. The well was drilled to a depth of 1,438 ft with native mud, and 51/2-in. casing was set and cemented to the surface. 2. The casing was perforated at 1,349 ft with a fracture-initiating jet gun. This gun consists of six shots, 7/16-in. diameter in a single horizontal plane. The jets were oriented in two groups of three, 180" opposed. The perforating device was designed to initiate a fracture perpendicular to the wellbore.

By R. E. Hurst, D. E. Ramsey, J. M. Moore

The "frac" method of well stimulation has been applied successfully to all producing formations in the Permian Basin area. During the five years since its development, many changes and improvements have been made in treating materials. procedures, and equipie11t. A number of fluid carrying agents, having different physica1 and chemical properties, have been developed to meet variorus well requirements. The current trend is toward larger gallonage treatments, employing higher injection rates. The use of "down-the-casing" techniques has greatly reduced high surface working pressures, attributable to friction losses resulting from injection throrugh tubing. Petrographic studies of various Permian Basin formations, coordinated with laboratory and well log data, have been found a valuable guide in planning frac treat111o1t.s. A knowledge of the extent (and orientation of naturally occurring fractures and planes of weakness in the formation, aid in predicting the ultimate drainage pattern resulting from the frac treatment. INTRODUCTION The South Permian Basin covers an area in Wcst Texas and New Mexico about onc-half the size of the state of Texas, This vast region has been called the "Permian Basin" for so long that the term will he used here. It includes an area south of the Matador Arch. approximately 250 miles wide and 300 miles long. Structural features of importance within the basin are the Northwest Shelf, Eastern Platform, Midland Basin, Central Basin Platform, and Delaware Basin. The principal producing formations include sand, limestone and dolo-mite, with lesser amounts of shale, anhydrite. chert. and various silicates. All of the producing formations in the Permian Basin have responded to some type of frac treatment. Essentially, a frac treatment may be defined as the injection, into a formation. of a fluid carrying agent containing a particulated solid (usually sand), for the purpose of increasing production. The application of this method of well stimulation to many differing Permian Basin reservoirs has necessitated numerous changes and improvements in carrying agents, solids, service equipment. well equipment. and treating techniques. CARRYING AGENTS A number of different types of fluid carrying agents have been developed since the introduction of the frac method of well stimulation. These agents have different physical and chemical properties, and in many cases the extent of production increase derived from the frac treatment depends on the choice of fluid carrier. Unfortunately, due to many different systems of nomenclature used in the oil field, these differences are not always recognized by the oil Operator. In general, carving agents may he divided into the following broad classi-

Jan 1, 1956

By George Moore

IN spite of many investigations of the occlusion of hydrogen in iron, the nature of the process and the reasons for the accompanying effects upon the metal are still open questions. This is in large part due to three causes: (1) the difficulty of obtaining iron of adequate purity as starting material; (2) the occurrence of allotropic transformations, which compli-cate the effects; and (3) the fact that the body-centered cubic modifica-tion does not lend itself readily to crystallographic investigation. The present paper attempts a critical review and correlation of the somewhat scattered and disconnected existing observations, and an experimental determination of the extent to which the conclusions that appear to follow from these are applicable to iron of really high purity, studied under well-defined conditions.

Jan 1, 1939

The Maas patent drill-hole compass, for determining the direction and dip of drill holes, is successfully used to a depth of 3,000 ft. APPARATUS FOR SURVEYING DEEP DRILL HOLES. The compass is placed in a thermos bottle or glass tube with hot liquid gelatine and lowered in a water-tight phosphor-bronze case, with a tube containing hydrofluoric acid. When the gelatine is cold the rods are pulled, the direction of the needle is marked on the tube which contained the acid, and the direction and inclination of the hole determined from this tube in a goniometer. There is nothing to get out of order and the compass can be used by any drill foreman, the mark and etching on the tube making a permanent record of direction and inclination. (See Fig. 1.)

Jan 1, 1916