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By E. B. REESER

EFFICIENCY is the foundation on which the prosperity of this Nation must be built. Your organization and the members thereof are constantly thinking of Gays and means whereby greater efficiency may be developed. It is often said that this Nation has become great because of its almost up limited supply of raw materials at low production 'costs. This was undoubtedly true in the earlier years but today we face an entirely different situation. We have learned that nature has been very generous in supplying all parts of the world with ample resources of various kinds to meet the demands. This applies to practically all commodities but for the purposes of this discussion, we will limit our remarks to petroleum.

Jan 1, 1931

By AIME AIME

THE best meeting ever held, was the opinion expressed by a number of those who attended the annual meeting of the Institute in New York, Feb. 18 to 21, and there was an atmosphere of friendliness and good fellowship about it that fully justified the feeling. In numbers it was not quite so large as last year and unless the Engineering Societies should build for themselves a new building it is probable that no meeting can be larger, in respect to numbers, than that held in 1928, which was only made possible by the circumstance that the eighth floor of the building happened to be, temporarily vacant at the time. The number of rooms available for -sessions that were provided when the building was built long ago proved inadequate, and it is only by the expedient of obtaining the temporary use of the board and committee rooms of other societies that it is possible to arrange for the over 40 sessions that must be spread over the four days of the meeting. The-fifth floor, where. a buffet lunch is served each-day, has reached its full capacity and it seems quite evident that any future development of Institute meetings must be along the lines of quality, not size.

Jan 1, 1929

MANY kinds of marcasite* are found since every metallic mineral, and perhaps some of the semiminerals, produces its own. I believe that [28v] rnarcasites are nothing other than the secondary materials and the menses of the conception of metals which, through insufficient time, have yet to arrive at their perfect age; and thus, because of

Jan 1, 1942

By J. D. Sudbury, J. E. Landers, D. A. Shock

The external corrosion of casing is one of the most important problems facing the present day production man. A 1953 NACE report' estimated the annual cost of casing corrosion at $2,200,000 in 22 fields studied. The fields represented only 10 per cent of the wells in the United States. It was significant that 77 per cent of the failures reported were due to external corrosion. A variety of means for combatting the casing corrosion problem have been discussed in papers such as the NACE survey' mentioned previously. No attempt to revicw these will be made in this paper. Thc scope of this paper has been limited to a discussion of the following major items: (I) an instrument for studying external electrolytic corrosion; (2) use of this instrument to determine the quantity of protective current required to prevent corrosion of casing; and (3) problem of accelerated external corrosion of the oil string at the base of the surface string. ELECTROCHEMICAL MECHANISM OF CORROSION It IS gcncrally belleved that one major cause of external corrosion is the existence of electrolytic cells operating between various formation waters. A theoretical discussion of the role of earth potentials in casing corrosion has been presented by L. de Witte and F. J. Radd.2 A brief picture of the electrolytic corrosion action between two differcnt formations (A and B) is presented in Fig. I. This picture is a review to many but is given to insure clarity. In the anode area, oxidation takes place as iron ions go into solution in formation A as a product of corrosion. In the cathode area. reduction takes place and hydrogen atoms are formed at the boundary between the pipe and formation B. The flow of electrons. as indicated. is into the pipe at the anode or corroding area and out of the pipe into the formation at the cathode. In order to conform with regulations of this journal, the flow of a conventional current (I! is also indicated in this sketch. All subsequent references will be to this so-called conventional current flow and will be indicated by the symbol (I). As this action takes place the layer of hydrogen developed on the cathode offers a resistance to the flow of current in the cell. It is said (hat the cathode has been polarized. This polarizing film can be rcmoved by addition of a so-called dcpolarizing agent which reacts with and removes this hydrogen film. Such an agent must be present in ordcr for this corrosion reaction to go at a rate sufficient to cause a severe corrosion problem. The two common depolarizing agents are: (I) oxy-sen. which readily reacts with hydro gen to form water, and (2) certain bacteria which use atomic hydrogen as part of their life process. It is not difficult to explain the presence of these agents. Oxygen may be present in some very shallow formations. Sulfate reducing bacteria are found to exist in nearly any ground where mud pits might be dug. THE CASING POTENTIAl-PROFILE Instrumentation A sketch of the equipment* uscd in determining casing potential profiles is shown in Fig. 2. The tool is run in the hole using a hoist truck with a three-conductor cable. This tool must be run with tubing and rods out of the hole and should be run with the flow line disconnected. By proper choice of electrode size it can be run in any size casing. The electrodes must be run in an open hole or a hole filled with oil. Measurements cannot be made while immersed in water. The tungsten carbide-tipped knives serve as the electrical robes and arc spaced 25 ft apart. The potential difference along a 25-ft section of casing is measured with a potentinmeter to an accuracy of about 5 mv. Current flowing in the pipe can then

Jan 1, 1956

Tars Committee is the result of a desire of the authorities in charge of the publications of the four national engineering societies to co-operate in this matter. The members of the Committee are the following: Charles WarreN Hunt, Secretary of the American Society of Civil Engineers. D. S. Jacobus, Vice-President of the American Society of Mechanical Engineers. Joseph Struthers, Assistant Editor of the American Institute of Mining Engineers. CaRy T. Hutchinson, Chairman of The Editing Committee of the American Institute of Electrical Engineers. This Committee has held several meetings; it seemed advisable, at the outset, to limit its discussions closely to the general subject of abbreviations. Further, it seemed best to formulate a few general rules to be followed in making abbreviations, rather than to compile a list of forms to be recommended. The Committee decided to limit the subject more narrowly by considering only abbreviations to be used in the text, or general reading-matter, arid not those to be used in special matter,

Jan 1, 1905

I HAVE striven to demonstrate to you as well as possible the method of bringing the metals of your ores to their ultimate perfection. But one cannot always do with gold that is found in the ores what is done with the other metals, for gold is not always accompanied by fine silver nor is it

Jan 1, 1942

By Charles M. Rolker

I desire to put on record this memorandum and accompanying sketch of a vein examined by me, in Honduras, Central America, which exhibits a well-marked banded structure. The illustration is of natural size: The vein traverses trachytic porphyry. It is from three to four inches wide. The central band, a, is of white quartz, one inch wide

Jan 1, 1886

Safety and health are no longer secondary responsibilities but must be of paramount concern to every mining operation, according to Anthony J. Thompson, an attorney with Hamel, Park, McCabe & Saunders of Washington D.C. The Mine Safety and Health Administration (MSHA) forecasts an estimated 19,000 inspections during 1979, and the economic and psychological impact of these inspections may he significant. To illustrate his point Thompson reviewed the experiences of a relatively large operation during a recent MSHA visit. The inspector was on the premises for two months, issuing between 250 to 300 "significant and substantial" (s&s) citations. During the most intensive period, about one month in duration, the operation experienced a production loss estimated between 2500 to 3000 tons; an accident rate up 30% over the previous month and 20% over the same month in the preceding year; 100% of the safety director's and safety engi¬neer's time was devoted to the inspection; 50% of top level management's time; and 90% of the mid-level or front line supervisory's time.

Jan 11, 1979

By Luis Toron, Salvador Cortes-Obregon

THE Oaxaca coal fields, shown in Fig. 1, are located in the Alta Mixteca region in the states of Oaxaca, Puebla, and Guerrero. Known out crops are scattered over 3125 square miles. It is probable that further exploration will reveal a more extensive area of deposits. The region is of great importance to Mexico, as at present the only sources of coal are the fields near the U. S. border. Steel mills are also located in the North, and finished products must travel 600 to 800 miles to the area of consumption in central Mexico. The Oaxaca coal, only 120 miles south of Mexico, D.F., lies close to several iron ore deposits. If this coal can be used in steel production is will be possible for the Mexican steel industry to reach new dimensions, commensurate with the growing industry of the central region. Coal can be utilized in thermoelectric plants in this area, which lacks not only petroleum and natural gas but also electric power. It can be used as domestic fuel, replacing charcoal and firewood.

Jan 5, 1954

By G. K. Burgess

G. K. BURGESS* and R. W. WOODWARD,? Washington, D. C.-From a metallurgical standpoint, there are several ways in which a reduction of the tin consumed in commercial non-ferrous and white-metal alloys can be effected. First, a reduction of the tin, content of the alloy; second, substitution of part or all of the tin content by some other metal; third, a substitution of a different type of alloy, which in some cases also involves a change in mechanical design. The Bureau of Standards has been studying these methods of conservation for tin alloys, particularly in regard to babbitts and bearing metals, bronzes, and solders. Much of the information secured by the Bureau was obtained from answers to questionnaires sent to manufacturers and users of these materials, so that, in general, any of the following suggestions or recommendations can be considered as being practical and as having already been thoroughly tried. Bearing Metals There is no question that the tin content of nearly all bearing metals can be reduced to some extent, and in some cases actually eliminated

Jan 12, 1918

By Sheldon P. Wimpfen

EVERYWHERE in mining circles the talk is of this new development of hard faced or insert bits which hints of many changes to come in mining practice and rock drill equipment. In the past fifteen years new equipment has appeared in rapid succession which brought one change after another in rock breaking practice. Detachable bits were an innovation which met with wide success. Blasthole diamond drilling has proven itself. Only recently, fusion piercing was announced as a possible solution to the problem of breaking taconite ores. For several years this interest in new methods has been growing and various experimental usages of tungsten carbides in rotary type rock drilling bits have been partially successful. American experts in rock drilling have been concerned with the subject for ten years but actual commercial practice was begun by European manufacturers and mining companies. At this time nearly every manufacturer of rock drilling bits is working on some type of an insert bit. On the Rand, European manufacturers are testing out various types of insert bits. The problems relating to rock drilling in South Africa vary greatly from ours. The bulk of the drilling there is limited to the 31/2-ft holes that are drilled for breaking the gold bearing reef ore. Rock drilling in most mines is far more diversified. Both drifting and ore breaking call for holes varying in length from 4 ft up to as much as 50 ft and more.

Jan 1, 1947

By AIME AIME

TWO papers, "Calcium, Strontium, and Barium Metals," by Charles Hardy and Paul M. Tyler, and "The Mining of Gems and Ornamental Stones by American Indians," by Sydney H. Ball, were presented before the Rare Minerals and Metals group at its session Tuesday afternoon in the Auditorium. Donald M. Liddell, chairman, presided. Mr. Tyler summarized the first paper, outlining the uses, history, occurrence, manufacture, production and trade, markets and prices of the three metals. In discussion, in response to the chairman's query on "what are they doing in Russia with calcium, strontium, and barium," Guy C. Riddell replied that nothing is being done on a production basis. The great rare metals plant in Moscow is active, however, on other elements. "They are making radium chloride, uranium oxide, vanadium, cadmium, tungsten, molybdenum, selenium, antimony compounds; and mercury, nickel and arsenic are under production at interior plants. The rare metals plant is busily conducting research on beryllium, rhenium, lithium, bismuth, strontium and zirconium. These are the main rare metal activities. Much hard-alloy work. for cutting and facing, is under way:

Jan 1, 1933

By A. F. Bridge

IN order to show the need for gas reserves, their control, and conservation, in California, it is necessary to describe briefly the local conditions under which gas is produced and marketed, to point out the lack of coordination between supply and demand, and to relate the history of efforts to prevent wastage. There are now 24 fields in California producing a surplus of gas over field fuel requirements. They are usually grouped geographically into three divisions, as follows: (I) Los Angeles Basin (Los Angeles and 0 r a n g e Counties), thirteen fields, all casing-head gas. Total daily gas available for sale 125,000, 000 ?cu.ft. (2) Coastal (Ventura and Santa Barbara Counties). Seven casine-head and one dry gas field. total-avail- able daily, 165,000,000 cu.ft. (3) San Joaquin Valley (Kern, Kings, Fresno, and San Joaquin Counties). Four casing-head fields, five dry gas fields, and two producing casing- head and dry gas from different zones. Total available daily pro- ducticon, 475,000,000 cu.ft. Total all fields, 765,000,000 cu.ft. daily.

Jan 1, 1936

By J. S. Marsh

TUESDAY, Feb. 16, was no day for strolling along the cold sidewalks of New York, and a large number of metallurgists sat down with pleasure to the warming task of wiping a few soldered joints. Presented by a joint-wiper of the modern school, G. M. Bouton, of the well-known team of Schumacher, Bouton, and Phipps, the initial paper brought into focus the theme of conservation of strategic metals and described the technique of making the fillet-type joint now employed by the Bell System. Using an over-all average of only 40 per cent of the solder formerly used by the conventional method. this important development bids fair to stick when the war is over. D. L. Martin and E. R. Parker then described the embrittling effect of hydrogen on silver previously heated in oxygen and the less serious but troublesome result obtained under the converse conditions. An interesting example of grain growth restriction created additional material for the lively discussion that ensued among those who have encountered one or another of these phenomena in silver and copper.

Jan 1, 1943

By C. M. Marquardt

Tramp iron and steel moving on a conveyor belt cause small currents to be generated in a coil situated in a strong magnetic field, which are converted to an alternating current and are amplified. The output voltage from the amplifier fires a thyratron with a relay in its anode circuit, which actuates a howler and simultaneously drops a spot of marker material on the belt.

Jan 1, 1950

By Luther Wagoner

HAVING given in a former paper1 the results of assays of sea-water, bay-mud, dredgings from San Francisco bay, etc., and' believing it might be interesting to extend the work to include' some deep-sea dredgings, I procured from the Smithsonian Institution six samples taken by the U. S, steamer Albatross, and marked as follows

Jan 9, 1907

By John Hays

AT the December Board meeting, the report of the William Lawrence Saunders Medal Committee, recommending the award of the medal to John Hays Hammond, was received and unanimously approved. The citation is: "For his notable work as an engineer and developer of mines at home and abroad, his industrial leadership and his public services." The medal will be presented as usual during the meeting in February, presumably at the annual dinner at the Waldorf, on Feb. 20. The other medals to be given on the same occasion are the James Douglas, which goes to Paul D. Merica, and the Robert W. Hunt, which is awarded this year to Edgar C. Bain, as already announced. This will be the third award made of the Saunders Medal for "Achievement in Mining," previous recipients having been David W. Brunton in 1927, and Herbert Hoover in 1928. The list is a distinguished one and Mr. Hammond's name is appropriately included. His career is so widely known that it is not necessary to repeat the account, published in MINING AND METALLURGY last April.

Jan 1, 1929

By Pradeep K. Rohatgi, David N. French, Surendar M. Jain, Clyde M. Adams

The effect of solute concentration and diffussivity on dendritic solidification of dilute binary aqueous solutions has been investigated; chlorides of sodium, potassium, lithiurn, and hydrogen were used as solutes. Dendrite spacings were measured in spherical droplets and in unidirectionally solidified specimens. In the droplets, the freezing rate is uniform over the entire specimen and remains constant from the beginning to the end of solidification. In the unidirec-tionally frozen specimens the freezing rate varies within a given volume of liquid during the solidification cycle; in addition, it varies with location uithin the specimen. Mass transport analysis has been used to calculate the supersaturation, AC, supercooling, AT, and transcerse growth velocity, V , of ice dendrites during solidijication from the dendrite spacings measured in the droplels. The ice dendrite spacing in a given solute increases lineary with the solule concentralion at a fixed freezing rate. The ualues of AC, AT, and V increase with an increase in solule concentration. The value of AT in the aqueous solution is of the same order of magnitude as in Al-Cu alloys of the same concentration; the dendrite spacings in Al-Cu alloys also increase with an increase in solute concentralion. For the jamily of aqueozrs solulions incestigaled, the dendrite spacing increases linearly with solute diffusivity at fixed values of concertralion and freezing ,rate. The values of ?C and ?T decrease, whereas the value of V increases with an increase in solule diffusicity. The measured dendrite spacings , L, can be expressed by the relatiun: L = K;(dfa/db) 4 K2C +K3D - K4 where dfs/d? is-change in fraction solid with time (freezing rate), C is solute concentration, D is solute diffusivit K1 = (14 * 4)pmin1'2, K2 = (70 ± 10) pl (moles)- K3 = (24 r 3) . l05 psec (cm)-~. K. = -132 ± 10) 1. FREEZING of solutions is almost always an ehunmix-ing" process because the composition of crystallizing solid generally differs from that of the parent liquid. " Solute concentration and transport are therefore in]portant considerations in solidification of solutions. The influence of these factors on the dendritic solutions produced from metallic solutions is of practical significance since the properties of the solid aggre-gate are often strongly influenced by dendrite spacing.''' Alexander and Fthines3 found that dendrite spac- ings generally increase with solute concentration in several metallic systems. Michael and Bever1 have observed an increase in a aluminum dendrite spacings in dilute A1-Cu alloys. Rohatgi and AdamsJ have reported a linear increase in a aluminum dendrite spacings with increasing copper contents up to 28 pct in A1-Cu alloys. Bolling and Tiller"' have theoretically examined the effects of solute concentration and diffusivity on the growth of cells and dendrites. Their analysis of dendritic growth assumes a steady-state growth and the maximum possible velocity for dendrite propagation. In addition, the quantitative analysis is restricted to dendrites of rotational symmetry and is therefore not directly applicable to the plate-shaped dendrites of ice obtained in the present study. There are practically no experimental observations of the effect of solute diffusivity on dendrite spacings in metallic systems. The reason appears to be the lack of experimental data on solute diffusion coefficients in liquid metallic solutions. The present work is concerned with the effect of solute concentration and diffusivity on dendritic solidification of dilute aqueous solutions: the solutes examined are potassium chloride. sodium chloride, lithium chloride. and hydrogen chloride. There were several reasons for selecting these solutes. The variation of dendrite spacing with freezing rate in these solutiolls is similar to that observed in A1-Cu alloys.8 These aqueous solutions have almost identical phase diagrams at dilute concentrations. Fig. 1. and the diffusion coefficients show very little variation with solute Concentration.9,10 Dendrite spacings were measured as a function of freezing rate. solute concentration. and solute diffusivity. Dendrite spacings were measured in two different types of freezing systems. droplet and unidirectional, respectively. In the droplet freezing system

Jan 1, 1970

By R. T. DeHoff, F. N. Rhines

The problem of determining the number of particles of a phase distributed randomly in unit volume c an opaque matrix from measurements made on random plane sections is closely investigated. A formalized derivation for the general case is presented. Applications of this formal result are made to specific types of aggregates dispersed in a matrix; circles, particles with flat circular ends, cylinders, and constant shape aggregates of ellipsoids of revolution. Quantitative measurements of the average geometric properties of these aggregates are developed. In 1953 R L. ullman' developed a technique for determining, from measurements made on random plane sections, the number per unit volume, Nv, of particles imbedded in an opaque matrix. Using meas urements previously developed for volume fraction, vV,' and surface area per unit volume, .SV,= he was able to determine average volume, average surface area, and average dimensions of particles, independent of size distribution, for spheres and circular disks,' as well as for uniformly sized cylinders of any axial ratio.4 The technique is mathematically rigorous for the cases studied. Recent studies of this problem have yielded rigorous solutions for the general case of cylinders, permitting evaluation of NV independent of size distribution and with all axial ratios intermixed. Generalization to shapes having flat, circular ends has been deduced. A solution has also been obtained for the ellipsoid of revolution, independent of size distribution, but requiring a constant axial ratio in the generating ellipses. In the following derivations, as in Fullman's work, it is assumed that the problem is purely a combination of geometry and probability theory,that is,eithe the particles to be measured are imbedded randomly in the matrix, or a sufficient number of random plane sections are taken to make the sample representative. A relationship exists between the number of par- ticles of a given size and shape that may be situated in unit volume (Ny) and the number of intersections a random plane can be expected to make with these particles (Na). It is the purpose of the following section to derive this relationship. The probability of Intersecting Convex Bodies. Consider a convex, closed surface, that is, one for which no two surface normals point in the same direction, situated at some arbitrary position and orientation in a cube of material that is one unit long at each edge. It is not necessary to assume that this surface is symmetrical. Let planes be constructed in the cube parallel to the top face and at random distances from it. Those planes which lie between the two planes which are just tangent to the top and bottom of the surface will intersect it. The probability that a plane will intersect the body may be defined as the limit of the fraction of planes that lie between the two tangent planes as the total number of planes constructed becomes infinite. This fraction, in the limit, is equal to the distance between the two tangent planes, DV, divided by the total length over which planes are constructed, which has been taken as unity. If the body is now rotated to a new orientation, applying the same argument, the probability of intersection is again numerically equal to the distance between tangent planes. Let DV ($, 0) be defined as the distance between tangent planes of a convex body as a function of orientation, Fig. 1. The probability, Pr, of intersecting the body with a randomly oriented and randomly positioned plane, is then equal to the average value of DV (0, $) over all possible orientations. It may be easily shown that for a system of spherical coordinates the probability of finding an orientation between Q and Q + de, $ and $ + d$ is (1/4n) sin $ dB d$, so that This relationship may be applied to each body in an aggregate of convex bodies. In particular, if the bodies in an aggregate are classified according to size and shape, and the ithsuch class is considered, Eq. 111 may be applied to this entire class, the probability of intersecting any body in this class being

Jan 1, 1962

Louis D. MILLS, San Francisco, Cal. (written discussion *).-The principle involved in the Crowe vacuum precipitation process is so elementary and the apparatus required is so simple, that the whole subject affords scant material for a technical discussion. As. one prominent Colorado metallurgist recently remarked when asked to contribute to this paper: "The Crowe process is the biggest step forward since the early clays of the cyanide process, but there is nothing to write about; just put it in your mill and try it." The writer confesses to a similar feeling, but having been closely identified with the process since its inception in 1916, he is perhaps in a position to at least comment on the theory involved and to record some of the results that have been achieved in actual practise. In practising the Crowe process, the solutions to be precipitated are first vacuumized in a suitable dispersion tower; that is, thin films of the liquid are subject to the action of a vacuum within a receiver. Sub-

Jan 1, 1919