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By Merlon C. Flemings, Theodoulos Z. Kattamis

Examination was made of the distribution of tnanganese and nickel in colutrrnar dendrites of a cast low-alloy steel; more limited work was corzducted on chromium. Corresponding "segregrction ratios" were calculnted and shown to be relntivelv insensitive to cooling rate (''segregation ratio" is defined (Is the ratio of maximum to minimum concentrations within a volume whose dimensions are the order of the dendrite-arm spacing). Isoconcentratiorl curves were determined by the electron micropvobe and by rt7etallografihic studies on specimens subjected to isothermal-transformation treatments. From construction of isoconcentration curves, morphology of columnar dendrites is descvibed as intermediate between Perfect rodlike and sheetlike morphologies. The study is extended to equiaxed dendrites and it is shown that the strcture of these dendrites is sittlilar in many respects to that of columnar dendrites. On the basis of tlze sheetlike morphology of dendrites, a simple model is pvoposed for calculation of honzogenization kinetics. Results of trzatllevlatical analysis brcsed on this utzodel are given. This analysis relates residual segregation to time at homogenization temperature; it is in agreement with experiment. Calculations are given which show that even for relatively rapidly cooled material (of 1-ine dendrite-artn spacing) treatmets at 1200°C or above are necessary to achieve slgxificant Izomogenization of elenlents other than carbon itz reasonable time (e.g., rnangclnese, nickel). Conlplete homogenization of carbon is obtnined at much lowev tenlperatures (below 870°C). IN dendritic solidification of castings and ingots, solute redistribution during freezing results in mi-crosegregation of most alloy elements. The micro-segregation is such that minimum solute concentrations occur at the center of dendrite arms and maximum concentrations occur between dendrite arms. Residual segregation after subsequent therma1 processing (homogenization) depends on maximum and minimum initial concentration, on the detailed geometry of the isoconcentration surfaces within interdendritic regions, on the diffusion coefficient of the solute, and on time of thermal processing. The objective of this work was to determine, for a low-alloy steel, maximum and minimum concentrations, and the geometry of isoconcentration surfaces, primarily in order to permit calculation of homogenization kinetics. Most of the work reported was conducted on Samples from a unidirectionally solidified, fully columnar ingot. This type of ingot is made by extracting heat during solidification from one face; techniques for accomplishing this have been discussed.' Samples were taken at several locations, up to 5.75 in. from the mold chill face; the bulk of the work was performed on samples at 5.75 in. Alloy cast was, nominally, 0.4 pct C, 1.8 pct Ni, 0.8 pct Cr, 0.7 pct Mn, 0.25 pct Mo, 0.3 pct Si, and the balance iron. Brief study was also made on samples from an ingot which solidified with equiaxed grain structure. SAMPLE PREPARATION AND ANALYSIS Samples for electron-microprobe analysis were incorporated in mounts that included pieces of electrolytic nickel, chromium, and manganese, in order to normalize the intensities of these solutes in the specimens; also, a piece of electrolytic iron was included to measure the background. All specimens were polished in the usual metallographic manner. After the microprobe traces were made, the path was revealed by etching the specimens with picral. All microprobe analyses were made by point counting, integrating for 30 sec. The distance between points was fixed from 2 to 10 p, according to the precision desired in each case, the fineness of the structure, and the concentration gradient existing in a given area. (The distance was chosen 2 to 5 p near the maximum-concentration regions and 5 to 10 p near the minimum concentration.) The "take-off" angle for the A.R.L.-Model No. 21000 microprobe employed was 52.5 deg. Samples for metallographic analysis of isoconcentration curves were prepared by austenitizing at 1540°F for 20 min, quenching to the nose of the TTT curves (1200°F), heat treating isothermally at this temperature for a given time 0, and then quenching to room temperature. Due to concentration gradients existing in a dendritic structure, no transformation will take place for a given time 0 of isothermal heat treatment in the regions where the a.lloy concentration is higher than a given limit. Thus, the dendrite appears limited by an isoconcentration curve and can be made to appear to grow by varying the time of isothermal heat treatment.

Jan 1, 1965

L. C. UREn,* BerkelEy, Cal. (written discussion).—I heartily concur with Rlr. .Fobs concerning the need for advanced courses on various phases of Petroleum Engineering. I think that his criticism is probably true of most of the engineering schools that are specializing at all in Petroleum Engineering, that is, that most of their so-called graduate courses are not of graduate caliber but are merely more specialized aspects of undergraduate subjects. It would undoubtedly be to the advantage of the petroleum profession if more advanced work could be offered in a few of the leading engineering institutions so that there would be something substantial to offer graduate students wishing to return after a period of undergraduate work, for additional training. There is no doubt but that a better trained engineer, more useful to the oil industry, could be secured from schools offering such advanced training. The problem of adpting our instruction to fit the needs of engineers trained along other lines who wish, after completion of their undergraduate work, to enter thc petroleum engineering field, is a more difficult one. It has been my experience that such men are usually sadly deficient along certain lines and that they are really not prepared for the more advanced work in Petroleum Production Engineering until they have gone back over the work which they have missed in their undergraduate training. I note that Mr. Fohs suggests that other eastern and western colleges not now stressing Petrolelim Engineering, should be encouraged to take up advanced work of this character. With this, however, I cannot agree unless the institutions arc also prepared to offer a full sequence of undergraduate work on which the more advanced courses may be superimposed. Whether or not there is a need for additional engi-ncering colleges entering the petroleum engineering field is an open qucstion. I believe that we arc turning out enough petroleum engineers at the present time and that none of the six institutions now specializing in this field arc overcrowded. Morc-ovcr, they are fairly well distributed over the country, though there may be room for an additional school in the field in the eastcrn section of the United States. F. W. Padgett, Norman, Okla. (written tliscussion).—Assuming that the stnclcnt has the proper fundamentals, that is, general science and a knowledge of the technology of the industry, then the problem is: What courses should be offered from the graduate standpoint? (a) Course Work.—His knowledge of the technology of the industry can be extended advantagcously by means of one and two-hour courses, which consist in a more detailed survey of the various branches of the industry. (b) Lilerdure.—This work may, or may not, be connected directly with his research problem. The student should become familiar with methods of locating articles in the 1iterature; should also become familiar with all the important original

Jan 1, 1928

By S. L. Craig, C. Orr, H. G. Blocker

WITHIN recent years gas adsorption methods have been developed for measuring the surface area of finely divided materials and have become extremely valuable in research on the corrosion and the catalytic activity of metals. Rather elaborate apparatus is required, and a single determination is so time-consuming that these methods have not been utilized to the fullest extent; the methods are un-suited for most routine control work such as that encountered in powder metallurgical operations and in processes employing metal catalysts. These difficulties are largely eliminated, and surface area is reduced to a routine determination if the liquid-phase adsorption of a surface-active agent such as a fatty acid can be used. When the affinity of the fatty acid carboxyl group for the solid surface is greater than its affinity for the solvent, a unimolec-ular layer of orientated fatty acid molecules will be formed at the solid-liquid interface in a manner similar to that of a compressed fatty acid film on a water surface. The measurement of surface area is then reduced to a measurement of fatty acid adsorption. This propitious circumstance, first investigated by Harkins and Gans,¹ has been employed with somewhat inconclusive results by a number of investigators in evaluating the surface properties of metals, metal catalysts, and metal oxides. The specific surface area values for nickel and platinum catalysts, determined from the adsorption of a number of fatty acids from various solvents, were found by Smith and Fuzek² to agree with values calculated by the gas adsorption technique of Brunauer, Emmett, and Teller," he so-called BET technique. And recently Orr and Bankston4 have also reported good agreement between nitrogen gas and stearic acid adsorption results in the measurement of the surface areas of clay materials. On the other hand, Ries, Johnson, and Melik5 found only order-of-magnitude agreement between these two methods in studying supported, cobalt catalysts having specific surface areas as great as 420 sq m per g; the reason is partially attributable to the very porous nature of the materials. Greenhill,6 investigating the adsorption of long-chain, polar compounds in organic solvents on a number of metal powders, concluded that a uni-molecular layer of stearic acid was formed on exposure of the solid to the acid solution and that the presence of an oxide or another film did not alter this result. Furthermore, the adsorption process appeared to be the same whether or not the sample was degassed prior to exposure to the solution. Greenhill estimated the surface area of one of the powders he investigated from microscopic diameter measurements, and obtained a rough check with surface area evaluation. Russell and Cochran7 found moderate agreement for alumina surface area results by fatty acid and gas adsorption methods. In addition, they also found that the prolonged heating and evacuating pretreatments previously used by investigators were unnecessary. The present work, however, considerably extends these previous investigations, shows that fatty acid adsorption can be used to determine the surface area of a variety of metals and metal compounds, offers further confirmation of the correctness of gas adsorption methods, and presents a simplified technique for the determination of the metal surface area which is suitable for routine work. Experimental Technique Basically, the fatty acid adsorption method is quite simple. It consists of exposing a sample of the material of which the surface area is desired to a fatty acid solution of known concentration. By analysis of an aliquot of the solution, the concentration after adsorption has occurred may be determined. The difference between the initial quantity of acid in solution and the final quantity is that quantity of acid adsorbed by the sample. The specific surface area of the adsorbent material may be calculated from the quantity adsorbed and the weight of the sample. In agreement with the findings of others as outlined above, it was found entirely unnecessary to degas or pretreat the nonporous materials employed other than by drying them thoroughly. However, precaution was necessary so that the dried sample entered the fatty acid solution with little exposure to moisture. The effect of moisture on the interaction of stearic acid with finely divided materials has been thoroughly investigated by Hirst and Lancaster." They found the presence of water merely reduced the amount of acid adsorbed by powders such as TiO2, SiO2, Tic, and Sic. With reactive materials such as Cu, Cu2O, CuO, Zn, and ZnO, however, water was found to initiate chemical reaction. Only with ZnO was reaction observed when the solid and the solu-

Jan 1, 1953

NEW MEMBERS The following list comprises the names of those persons who became members during the period Oct. 10 to Nov. 10, 1915: Members BECK, WESLEY HUDSON, Civ. and Min. Engr., Ellsworth Collieries Co., Ellsworth, Pa. BRADSHAW, GRANT D., Pres., Andrews-Bradshaw Co, 409 Diamond Bank Bldg., Pittsburgh, Pa. BUTLER, BERT S., Geol U. S. Geological Survey, Washington, D. C. CAMERON, FRANK, Asst. Mine Foreman, Braden Copper Co., Rancagua, Chile, So. Amer. CHEN, YEFAH FRANCIS, Asst. Min. Engr., Pinghsiang Colliery, Pinghsiang-Ki, via Changsha, China. CLAGHORN, DAVID MONTGOMERY, Mining Engr., Timekeeper, Wilkeson Coal & Coke Co., Wilkeson, Wash. DAVIS, REUBEN WALDO, Min. Engr., Supt., Cannel Coal Co., Dolores, Webb Co., Tex. DOUTHETT, GEORGE M., Supt Crescent Metals Co., Glenwillard, Pa. DUNSFORD, ENSOR R., Min. Engr., Asst. Supt., Victoria Gypsum Min. & Mfg. Co., Ltd., Quarry, St. Alms. C. B.. Nova Scotia. Canada.

Jan 12, 1915

[This paper was presented for the author, who is now in the National service, by H. M. Chance, and was illustrated by a working model built to the plans shown in the Bulletin, for February, 1918, p. 268. For more convenient operation, a small motor-driven centrifugal pump was attached to the overflow outlet (5, Fig. 1, p. 267) delivering to the inlet, 4. The pressure of ingoing water was then adjusted by a valve at 4, and was indicated by the column of water in a vertical glass tube connecting with the pressure chamber; an average pressure of 15 in. of water column was maintained during the demonstration. The sand used in the test was beach sand, which had simply been passed through a 20-mesh screen; about 45 per cent. was finer than 80 mesh. The circulation of water was at the rate of about 5 gal. per square foot per minute, and the rising velocity of the water in the box as a whole (not the velocity of the jets) was 6 in. per minute. At this consistency, the specific gravity of the fluid mass was between 1.55 and 1.60. Mr. Chance estimated that it would be possible to maintain a fluid mass of this consistency, 3 ft. deep, and with an area of 50 by 60 ft. with an expenditure of 15-hp. Mr. Chance then showed how a lump of coal would float on the fluid mass, and also made a separation of slate from coal on a small scale in a wire cage submerged momentarily in the fluid. The following demonstration relates to a matter not contained in the original paper, and was presented as of interest to the operators of cyanide and other lixiviation processes dealing with fluid mixtures of varying specific gravity.-Ed.]

Jan 4, 1918

By R. E. Reed-Hill, W. H. Hartt

The "(3034) " twin lamellae in magnesium have been reexamined using electron microscope replicas. The double twinning sequence (1011)- (1012) for these lamellae has been reconfirmed. Evidence is presented showing that the irrational habit of these twins is probably the direct result of a need to accommodate the second-order twinning shear. This accommodation vesults in both an external shear in the matrix and an internal shear in the lamella. A model is presented which accounts for the experimental obseruations. HCP metals are generally characterized by strong textures in which the basal planes of the grains tend to be aligned parallel to the rolling direction in sheet or plate and to the axis of wires and rods. Since these directions are normally those in which finished products may be subjected to uniaxial tensile stress, these textures effectively place the crystals of magnesium objects in orientations unfavorable to both basal slip and {1012) twinning, the easily activated deformation systems of this metal. However, when magnesium crystals are deformed near room temperature by a tensile stress nearly parallel to the basal plane, another mode of deformation can occur.',2 This is _a double twin which forms first by twinning on {loll), followed by retwinning on (1012). The resulting twin lamellae are of considerable interest. First, they can be responsible for "brittle fracture''; when a tensile stress axis lies in the basal plane, because the reoriented crystal structure of a lamella is well-aligned for slip while the parent crystal is not. Extensive internal deformation may thus occur while the matrix is still almost undeformed. This deformation can produce a ductile rupture running the length of the twin.3 Complete failure of the specimen may then oc-cure by the spreading of cracks from one twin lamella to another, or by the movement of a crack into a grain boundary and then along grain boundaries. Since the the volume fraction of these doubly twinned elements is normally very small, the fracture may be classed as brittle, although the fracture mechanism is, of itself, essentially ductile. It is quite probable that the ductility transition, normally observed4 in magnesium at or slightly Obove room temperature, is closely associated with these second-order twins. The detailed relationship of these twins to fracture in single crystals will be the topic of another paper. The present paper is concerned with a second important aspect: the irrational habit of these double twins that falls close to {3034), or approximately 7 deg away from the primary (10il) twin habit. There is good reason to believe that this habit results directly

Jan 1, 1968

IN the western mines, the boss, engineer, geologist, or nipper in making rounds have a password which usually guarantees safe entrance to a working place from below the working miner. Most men won't climb a raise or enter a stope from below where a miner is working until they have shouted "nothin' down" and heard those words shouted back by the miners above. "Nothin' down" is a safety pledge as necessary and as binding as the truce flag to the soldier. It implies mutual confidence that work will be suspended until the person below has come abreast of the workers; and also confidence that the miner who replies "nothin' down" is reasonably sure the place is safe to enter. Like truce flags which are not infallible, so is this password subject to human errors or unexpected falls of rock, tools, or timber. Everyone knows these unavoidable hazards, but what is important to the exposed man is that in that precise moment of time when he has heard the reassurance of "nothin' down," he knows that safety is uppermost in the minds of the men above him. With such assurance we would go anywhere and so would most mining men. If that period of safety consciousness, procured by the utterance of two words, could be multiplied to equal the hours in the working day, there would not be any accidents but those by "the act of God." It is the aim of every safety program to make safety as natural as breathing. That is the reason for the posters, the conferences, instruction periods, safety engineers, and the inspections. But none of these are as effective as one accident, which keeps men on their toes for weeks to come. This is not the price we want to pay for safety consciousness. This Annual Review number of Mining Engineering is full of talk about production. Production for defense, production for profit. In this tremendous surge of industrial might . to make this nation and our very families safe S from the predatory forces abroad in the world today; let us not lose sight of the fact that the . safety of our manpower is more precious than any commodity. Production without safety is detrimental to the national interest, to that of the company, and to the individual. If the words "nothin' down" can give us the best human guarantee of safety, for however brief a time, let us adopt them at least in principle as our slogan in 1952. Production for preservation in '52 - but NOTHIN' DOWN!

Jan 1, 1952

By A. E. Himebaugh

A SEMI-AUTOMATIC hoist has been installed at the 2966 station of the Copper Queen mine, since neither the bulk of supplies handled nor the number of men engaged in developing the 3100 level justifies the constant attendance of two cagers and two hoist operators. The connecting service shaft between the 2966 and 3100 levels is actually a two-compartment raise. Below the 2966 level the shaft is 7x13 ft-slightly oversize to permit downcast ventilation and provide space for the 16-conductor flexible control cable. The raise extends 52 ft above the 2966 level for a 3-ft diam head sheave. Another 3-ft sheave is mounted as an idler between the hoist and head sheave, eliminating the need for an inclined cableway. The main compartment serves as a cageway; the other compartment provides a manway and space for service lines. Since vertical travel is limited, rope speed is of minor importance.

Jan 5, 1958

By K. R. Janowski, A. B. Chase, E. J. Stofel

Ruby crystals of exceptional optical quality have been grown from fluxes composed of Bi2O3 + PbF2 or Bi2O3 + BiF3. Careful control of growth conditions was required to minimize the number of growth defects consisting primarily of dislocations, occluded flux, and growth twins. Slow growth rates coupled with the addition of small amounts of La2O3 as a flux dopant were helpful in producing nearly perfect crystals. Chromium concentrations up to 1 pet were incorporated into these crystals without adversely affecting their perfection. Crystals up to 10 mm in diameter having as few as one to ten dislocations per crystal were typical of those produced under optimum growth conditions. Under these same conditions the occlusions were eliminated, and growth twins were either eliminated or reduced to one to three twin boundaries per crystal. INTEREST in the nature of lattice imperfections produced during the growth of ruby crystals (Al2O3-corundum structure) has been stimulated recently by the need for ruby lasers of good optical uniformity. As a result, ruby crystals grown by the flame-fusion (Verneuil) process have been studied in detail and have been found to contain high densities of dislocations (106 to 107 dislocations per sq cm) and mosaic structures that impair their optical quality.'-3 Attempts to improve the quality of Verneuil-grown crystals by controlling the growth variables have not been entirely successful. On the other hand, rubies grown by the flux process have received little attention even though their more nearly equilibrium growth conditions suggest that they would have fewer growth defects. Nelson and Remeika have shown recently that small flux-grown rubies can indeed be made into very low-loss lasers. However, they did not report information on crystalline imperfections in these crystals.4 Stephens and Alford have reported briefly on defects found in a flux-grown corundum crystal but they neither described these defects in detail nor related them to the method of growth.5 The present investigation was undertaken to establish the relationship between growth conditions and crystalline perfection of flux-grown rubies, sapphires, and other crystals of the corundum family. EXPERIMENTAL PROCEDURE The corundum crystals used in this study were grown by slowly cooling solutions of A12O3 in molten-salt solvents of PbO + PbF2, Bi2O3 + PbF2 or Bi2O3 + BiF3. The materials employed were Linde A (a Al2O3 powder) with reagent-grade chemicals as solvents. Some of the solutions also contained small additions (1 pet or less) of one or more of the transition metal elements chromium, manganese, iron, and titanium as crystal dopants. La2O3 was added to some of the solutions to alter the growth habit of the crystals. The La2O3 promoted the occurrence of growth facets parallel to (0112) and {1011} planes, where the indexing system is the morphological system described in detail by Kron-berg6 and used throughout this paper. The melts from which the crystals were grown were prepared by mechanically mixing the various constituents and placing them in platinum crucibles. The covered 50- and 100-ml platinum crucibles were heated in muffle furnaces at 1250°C for short periods of time (1 to 4 hr) and then program-cooled at either 2° or 4°C per hr to 1000°C. At this lower

Jan 1, 1965

By D. R. Walker, M. C. Shaw

The laws of Kick and Rittinger are explained as functions of particle size with metal cutting theory. Comminution is shown to be basically the same process as metal grinding. The machine shop type of grinding operation is used to study mineral crushing. Evidence indicates that plastic flow occurs in comminution. THE laws of comminution of Kick and Rittinger have been debated for many years. Certain data obtained from ball mill and drop tests are found to be in approximate agreement with Rittinger's law while other data would seem to support Kick's law. In all these tests the energy required to produce a wide variety of particle sizes has been studied. Surface area has also been measured with considerable difficulty, at first because it was thought that the energy associated with crushing was that required to create new surface, later because of precedent and because a more fundamental variable was unknown. Tests made with the machine shop type of grinding process show that normally brittle materials that are usually crushed can behave like the more ductile metals. Brittleness is then a relative prop- erty largely dependent on specimen size and stress state. The machine grinding operation offers a convenient means for studying the comminution of materials in which the important size variable retains its identity. The energy required to grind a certain volume of material is shown to be strongly dependent on size. Kick's law is found to hold very well for particles below 1 micron in size, while Rittinger's law holds approximately in the comminution of larger particles. While a physical origin of Kick's law is established in terms of the theoretical strength of materials having a perfect lattice structure, there is found to be no physical basis for Rittinger's law. Because of its industrial importance, comminution has commanded considerable technical attention and has been the subject of continuous study for nearly a century. A number of empirical rules have been proposed to make it possible for grinding energies to be predicted. Of these so-called laws of comminution those bearing the names of Kick and Rittinger have been most widely applied and debated.

Jan 1, 1955

Escalating energy costs and tough environmental standards were two major factors affecting the minerals processing area in 1978 For the most part, new startups and research and development initiatives were directed toward improving process dynamics, investigating alternative processing strategy, and lowering unit costs. In the flotation area, the trend to larger machines continued. Scientific investigation of the modeling and process control of flotation was apparent, as was the research and development of new flotation reagents.

Jan 5, 1979

By John Freeman

THE die pressing of brass may be described as a method of producing irregularly shaped parts of brass and other copper alloys by hot deformation in a die under pressure. Die pressing of brass was first developed as an improvement on sand castings in order to obtain irregularly shaped articles of brass with superior surfaces, a closer tolerance in dimensions, a denser structure, freedom from porosity and elimination of the relatively large amount of scrap invariably attached to sand castings. The freedom from sandy surfaces with consequent greater tool life in machining operations was also recognized as well as elimination of losses due to the uncovering of blowholes in machining operations. Die pressing also gave alloys of superior strength. Die pressings today are made from extruded rod or shapes, according to design of the part to be made. The greater number of pressings are made from round rod, because of its relatively lower cost and ease of handling. The rod is first sheared or sawed into desired lengths, the diameter of rod used and length of "slug" or "rivet" depending upon ultimate weight and shape of the die-pressed part to be made and design of die. The dimensions of the slug are figured so as to give the, minimum amount of scrap to be sheared from the pressing as it comes from the-die. Extruded shapes having I, T or X sections are often used when the finished part is to have a similar shape or heavy sections are joined by relatively light sections of considerable length. A rod bent in the shape of a U is also used on occasion, for similar reasons. Proper shearing of the slugs is of considerable importance. The sheared ends of the slugs should be as flat and straight as possible. Improperly sheared ends having an angle to the axis of the bar or a rough, uneven surface are liable to give folds or laps in the finished pressing and proportionately high rejections. The property of shearing varies considerably with different alloys and should be considered in the selection of a material for a given part. Where satisfactory shearing is not possible, the slugs may be cut from the bar by power saws. Extruded

Jan 1, 1931

Discussion of the paper of E: D. Gardner, presented at the Salt Lake meeting, August, 1914, and printed in Bulletin No. 91, July, 1914, pp. 1467 to 1471. H. V. WINCHELL, Minneapolis, Minn.-There are two questions I should like to ask: First, does the Department still adhere to the decision made in the East Tintic case? Second, does the Department require placer ground to he of such value that, in the opinion of the Forest Service employees, it will pay to work, before admitting the location to be valid? T. C. HOYT,* Ogden, Utah.-With reference to the first question: the Department does not hold to that decision, as it was reconsidered by the Secretary Of the Interior, and the Department is governed by the decision of the Secretary Of the Interior, on those points always. The Department of Agriculture makes no decision as to what constitutes a sufficient discovery. The mineral examiners simply report their findings and Opinions. These are transmitted to the chief of the field division of the General Land Office, who in turn transmits the reports to the Commissioner Of the General Land Office, who decides whether the report raises an issue requiring a hearing. If a hearing is ordered, expert testimony is given on the question of the discovery, as well as the evidence of practical people who operate in the vicinity of the claim in question. As to the extent of placer values considered sufficient to justify a location, my answer will need a little amplification. I couldn't answer it directly for the reason that sometimes people resort to placer claim location as a means of acquiring land for Other purposes than placer mining, which makes it absolutely necessary that the government give close attention to the question of whether good faith has been shown, as it is the evidences of good faith that largely determine whether a report adverse to a claim shall be made. That is a difficult point to cover sometimes. For instance, in the region I have recently visited there are some 17 miles of a valley, from ¼ to ¾ mile in width, all covered by placer locations. It is valuable stock-grazing land, and is stocked at the present time. It also contains a stand of timber, and is on the watershed of an important stream-important from the fact that it furnishes the water supply to government storage reservoirs, and to pending reclamation and Carey Act projects. In this case the placer claims will not be disturbed as mere locations. They will simply remain there, and there will be no action with reference to them until the claimant asks for patent or, before patent, begins to denude that watershed and remove that timber. Then the government would direct that the mineral experts go on to the ground, examine it, prospect it, and submit their report, with a view to seeing if

Jan 11, 1914

By P. V. Roundy

PUBLIC lands in Florida were first withdrawn from entry by President Taft on July 2, 1910, as a conservation measure because of their possible phosphate content. The reserve thus established was subsequently modified by further withdrawals and by restorations, so that on Jan. 1, 1934,' it contained 66,796 acres, of which only a small part had been defi-nitely classified. The reserved land was in scattered parcels, ranging from less than 40 acres to 320 or more, distributed in many counties. For administrative purposes and for final disposal of any of the numerous parcels, mineral classification of the land is legally necessary. In 1934 and 1935 the United States Geological Survey, under two successive grants from the Public Works Administration, prospected some 83 tracts of these lands in Polk County, comprising in all about 3300 acres, and six tracts comprising 240 acres in Citrus and Marion Counties. The tracts in Polk County were all in the so-called land-pebble field and the others in the hard-rock field. The Survey field party was under the direction of P. V. Roundy, from whose unpublished report the material in this paper is largely taken. The foreman of the prospecting crew was J. H. Wingate of Zephyrhills, Fla. The individual tracts were identified through the cooperation of the General Land Office, by transitman Hugh B. Crawford. This prospecting work fitted well the classification adopted for Public Works projects in general: it could not he done on any considerable scale under the Survey's usual appropriations; it gave employment to unem-ployed labor; and it may be expected ultimately to repay the Government in royalties more than the cost of the exploration.

Jan 1, 1937

By D. L. Katz

In the management of oil properties, it is always desirable to know the future behavior of oil wells and oil reservoirs. Some estimation of the quantity of oil and gas that will be produced must be made as a basis for decisions on possible returns on investments in lifting equipment, drilling of additional wells, and other operating expenditures. In new or wildcat areas, operating expenditures are considered highly speculative, but in the completion of partly drilled and the operation of producing fields it is good business to remove as much speculation as possible. An accurate knowledge of oil and gas reserves in such cases would solve many management problems. The term "oil reserves" usually signifies the future ultimate recovery without specifying the method of production. Thus with changing methods and innovations in the production industry, reserves of any definite reservoir may be increased by increasing the portion of oil recovered. The usual reserve estimates are made by comparisons of well and formation characteristics, by using a percentage recovery on the oil content of the formation volume using porosity data, by extending production curves on non-prorated wells, or by extending bottom-hole pressure-production curves. The most reliable method would appear to be one that would estimate the initial quantity of oil and gas present and then obtain percentage recovery values for various productive methods and formations from experience. It is the purpose of this paper to describe a method of estimating the initial quantity of oil and gas present in a reservoir. The method is based on field operating data and the properties of crude oil-gas mixtures. The principles involved, the data required, the assumptions necessary, and an example of the method will be given. The method is entirely independent of sand volumes and formation porosities. Principles of Method The method of estimating the initial quantity of oil and gas present is based upon the premise that the volume occupied by oil and gas in the reservoir is constant and that a mixture of crude oil and gas will behave in

Jan 1, 1936

By F. Forward, H. Veltman, A. Vizsolyi

Activities of oxides in the ternary FeO-MnO-SiO system are calculated from data on the binaries, using the Gibbs -Schuhmann method. These activity data are used, together with thermodynamic relations, to calculate the contents of oxygen, silicon, and manganese in liquid iron, and the composition of the corresponding oxide phases in equilibrium with it. Excellent agreement was found between calculated and experimental metal compositions, indicating that thermodynamic methods, such as those presented, can supply useful data on slag-metal equilibria, and are therefore capable of wider application. When molten steel containing oxygen is treated with a deoxidizer, the product of the reaction is composed of the oxides of the deoxidizing elements together with more or less iron oxide. This assemblage of oxides is presumably very close to equilibrium with the melt since it is formed directly from elements dissolved in it. Therefore, it is likely that metal analyses corresponding to a given oxide phase composition are calculable with considerable precision where sufficient information is available on activities in both phases. The present study was made to test this hypothesis in the case of deoxidation by silicon and manganese. Here experimental data on the relationship among oxygen, silicon, and manganese in the metal phase are available, as are activity data for the MnO-SiO2, FeO-SiO2, and FeO-MnO binary systems. A further objective was to demonstrate in a specific example how gaps in the data may be filled by judicious interpolation, and how the Gibbs-Schuhmann method is applied to obtain activities in ternary systems. The rigorous derivation of the latter, requiring considerable facility in handling partial differential equations, tends to mask the real simplicity of the method, and repel the very engineers and experimenters who would benefit the most from its use. I) GENERAL PROCEDURE Deoxidation of steel with silicon and manganese results in the formation of two phases, metal and oxide. The number of components is four—Fe, Mn, Si, and 0. The phase rule then gives the number of degrees of freedom: If temperature and pressure are fixed, 2 deg of freedom remain. Consequently, it suffices to fix the concentration of two of the components of the system for all the concentrations to be determined and, at least in principle, calculable. The practical problem is then to discover a straightforward method of calculation with a minimum of trial and error solutions. The type of reactions to be dealt with are like the following: Si (in steel) + 2 O(in steel) = SiO2(in oxide phase) The standard free energy of this reaction is readily obtained from the literature, so that the equilibrium constant can be calculated by the expression: Since the metallurgist is concerned with percentages rather than activities, a real solution requires information that will permit activities to be converted to concentrations. This information is fairly adequate for the elements dissolved in molten steel, but is not available for the FeO-MnO-SiO2 oxide system. Therefore, the first step in this study was to find the relation between activity and concentration for the three oxides making up the system. The next step was the calculation of slag and metal compositions that are in equilibrium with one another. As shown by the phase rule, it is sufficient to assume the values of two composition variables in order to calculate the rest. But which two are picked makes a vast difference in how difficult the calculation turns out to be, so that it is necessary to make preliminary trial of several routes to find the easiest one. A convenient method is to begin with the slag, and to pick FeO concentration and that of one of the other oxides. Starting with the relation between oxygen dissolved in the liquid steel and FeO in the slag permits a good first estimate to be made of the oxygen content of the steel in equilibrium with FeO, because the iron content being fairly close to 100 pct, Fe has an activity close to unity. Using this first estimate of oxygen activity, approximate values of the manganese and silicon contents of the melt are readily calculated from the appropriate equilibrium constants. A minor correction for the depar-

Jan 1, 1963

By F. R. Hensel

PURE silver and silver-lead alloys have been studied as to their suitability for bearings.1-8 A review of the properties of thallium and the silver-thallium constitutional diagram was made by the author to analyze the possibilities of silver-thallium compositions for antifriction materials.† The silver-rich end of the diagram as reported in the literature9-11 was found to be sketchy and it was necessary to carry out considerable experimental work to arrive at definite conclusions. Some of the results of this work are reported in this paper. TEST MATERIALS In the beginning of the work, only fused alloys were investigated. Later, research [TABLE I. Composition of Fused Silver thallium Alloys Tested for Antifriction Properties PERCENTAGE ALLOY No.OF THALLIUM 15330.48 153406 231 HT2.04 2312.10 232 HT3.83Balance 2324.07Silver 233 HT5.86 2336.38 2349.84 234 HT10.07] was carried out on electroplating methods and diffusion processes. In preparing the fused alloys, care was taken to exhaust the toxic fumes caused by the thallium content. The compositions of the series of fused alloys are listed in Table I. The silver-thallium alloys were melted in clay-graphite crucibles and cast into preheated steel molds of 3/4-in. diameter. In the cast condition, they showed a cored structure, as indicated by the micrographs of Figs. I to 3. The etching reagent used was a mixture of 2 grams K2Cr2O7, 8 c.c. H2SO4, and 100 c.c. H2O. The cored structure is unsatisfactory for the type of corrosion resistance required for bearing applications, and homogenizing experiments were carried out at various temperatures, the results of which are shown in Figs. 4 through 8. The alloys with a lower thallium concentration, which were heated for 2 hr. at 525°C. show an almost completely homogenized solid solution type of structure. With higher thallium concentration, the homogenizing temperature was dropped to 475°C. to eliminate the formation of a liquid phase. It is evident that heating for 2 hr. at this temperature did not result in complete elimination of the cored structure. As would be expected, cold-working of the cast structure is an expedient in establishing equilibrium conditions. The fine homogeneous grain structure shown in Fig. 7 corresponds to the cold-worked area under the Rockwell ball penetration when the hardness was taken before heat-treatment. A detailed structural study was made on a cast silver-thallium alloy containing 3.67 per cent thallium. Three micrographs (Figs. 9, 10 and 11) show the transition

Jan 1, 1945

By William C. Aitkenhead, John A. Jaekel

Uranium deposits in the Spokane Indian Reservation, as well as those around Mt. Spokane, are essentially low grade, much of the ore containing less than 0.2 pct U808. The Mining Experiment Station of the Division of Industrial Research, State College of Washington, has been engaged in intensive research on the amenability of these low grade ores to froth flotation. The results: successful flotation of autinite, chief mineral constituent. At the outset of this work the goal was a concentrate of 1 pct U308 with a 90 pct recovery from ores containing less than 0.2 pct U3O8. Most of the work has been done on argillite ore from the Midnight mine on the Spokane Indian Reservation. The goal has not been attained using this ore, but samples of the granite ore from Mt. Spokane yielded successful results. For example, a concentrate containing 11.2 pct U308 was produced from a Mt. Spokane high grade ore containing 1.27 pct U3O8 with a recovery of 97.8 pct. Another Mt. Spokane ore yielded a concentrate of 5.0 pct U3O8 from an ore containing 0.13 pct U3O8, with a recovery of 85 pct. This same ore gave a recovery of 93.5 pct when the grade of concentrate was reduced to 2.0 pct.

Jan 1, 1959

REJUVENATED is an apt word to apply to Chino, Kennecott's big open-pit mine at Santa Rita, New Mexico. Back in 1923 Chino was merged with Ray by an exchange of shares, and in 1926 the Ray-Chino combination was taken over by Nevada Consolidated through an issue of bonds that were traded for the Ray and Chino assets. Subsequently, of course, the whole package was acquired by the Kennecott Copper Corporation. On the basis of the terms of the Ray-Chino-Nevada exchanges, Chino was rated third in value, something less than thirty per cent of the total. In 1955 the appraisal would doubtless be forty per cent or more. But it is not only vis-a-vis Ray and Nevada that Chino has blossomed out. At the end of 1931, Chino ranked seventh among the Porphyries in point of output; whereas by the end of 1954 it was fifth,. having passed both Inspiration and Nevada Consolidated. Sharp curtailment in production in 1932-33-34 and total suspension in the two years following (see Fig. 21) found the property in a somewhat parlous position. However, the engineers had not been idle; they had been planning for the future, and in 1937 a far-reaching program of rejuvenation was launched. During the ensuing five years, capital expenditures totaled more than $8,500,000. Among the projects undertaken were the following: (1) Mine-Purchase of larger and better equipment for drilling, loading, and transporting the ore. (2) Mine-Beginning of the first systematic project to leach and recover copper in the waste dumps at the mine.

Jan 1, 1957

By Edward Keller

Although the subject matter contained in this paper is presented under a new title, its writing was induced by the work of S. Skowronski and K. W. McComas.' A discussion of the latter is here combined with the presentation of new and independent data. The' physical constants quoted by the authors of that paper, such as melting and boiling points, as also the chemical reactions of the substances involved, are so well established that the numerous confirmatory experiments and their application to metallurgical conditions leave little or no room for criticisms. On the contrary, they will greatly aid to dispel any lingering skepticism as to possible considerable losses of copper accruing when the metal is melted in the presence of its own and, probably, other chlorides and when no provision is made for the recovery of volatile products. Exception may be taken, to some degree, to that part of the work under the caption Melting Drillings of Copper Mixed with Sodium Chloride. These experiments should have been extended in order to make the implied reactions clear and the results convincing. The latter are stated to be, "that when sodium chloride is present above certain minimum quantity relative to copper some of it is found to volatilize in the melt while another part reacts with the metallic copper to produce the volatile cuprous chloride, and that when smaller quantities of sodium chloride are present the reaction is complete and all chlorine is found to have volatilized as cuprous chloride." Metallic copper and sodium chloride are mentioned as the sole reagents in this chemical process, acting, according to the authors, in a neutral atmosphere of carbon dioxide. The chemist, quite naturally, wi11 inquire into the formula according to which that reaction takes place and will find that it presents itself as follows: 2Cu + 2NaCl = 2Na + Cu2Cl2 It would appear that the truth of this formula will be challenged and a more rational explanation of the reaction sought. Apparently, carbon dioxide is neutral relative to metallic copper in its molten state; whether it remains neutral in the presence of sodium chloride is quite another

Jan 1, 1921