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By W. A. Hooker

This portion of Mexico is quite beyond the ordinary routes .of travel, and is seldom visited. Its mines have not the record of enormous wealth which has recently attracted foreign capital to other parts of the republic; but for many centuries it has been a mining country, and at some periods evidently a productive one. In 1881 the writer visited the State and spent some time in the inspection of the mines. The absence of published information regarding its mining industry is his apology for presenting to the Institute these notes on the subject. Oaxaca is, with one exception (Chiapas), the most southerly of the Mexican States. It extends from latitude 18o 20' to 15' 45' N.— about 180 miles, by some 300 miles, in an east and west direction, and embraces a large part of the Isthmus of Tehuantepec. The coast-line is wholly on the Pacific. The State has an area of 27,470 square miles, nearly that of the State of Maine, and a population estimated at one million, or thirty-six to the square mile. The great continental Cordillera which farther north and west expands into broad table-lands, is here converged into narrower limits and occupies the greater portion of the country; the main

Jan 1, 1887

The Arizona Committee, consisting of GERALD F. G. SHERMAN, Chairman, ARTHUR NOTMAN, Secretary, NORMAN CARMICHAEL, B. BRITTON GOTTSBERGER, W. L. CLARK, J. C. GREENWAY, W. G. MCBRIDE, FOREST RUTHERFORD, has arranged the following program for the Arizona Meeting, which has been approved by the President of the 'Institute and by the Executive Committee. It is printed herewith for the information of members, and probably will not be changed in any material respect. Monday, September 18, 1916.-Arrive at El Paso, Texas,, 6.30 A.M. Arrive at Deming, N. Mex., 9.30 A.M. Arrive at Chino, Ariz., 11.30 A.M., where luncheon will be served, after which there will be a visit to the Chino mines. From there the train will proceed to Hurley, N. Mex., where a visit will be made to the mill of the Chino Copper Co. Tuesday, September 19, 1916.-Arrive at Douglas, Ariz., at 8.00 A.M. The morning will be spent at the reduction works of the Copper Queen Consolidated Mining Co. "and of the Calumet & Arizona Mining Co. After luncheon a technical session will be held, with "Smelting" as a special subject for discussion. There will be a banquet in the evening, followed by another technical session or-a business meeting.

Jan 6, 1916

I. C. WHITE, Morgantown, W. Va. (written discussion *).-The writer's conclusions with reference to the possibility of finding commercial deposits of petroleum in Brazil were published in 1908 in the Final Report of the Coal Commission of Brazil.1 Since this volume is not generally accessible, and the author has nothing to acid thereto, the following quotation found on pages 243-7 may prove of interest: The Possibility of Petroleum Deposits in Brazil "The writer has often been asked to express an opinion as to the possibility of finding petroleum in commercial quantity in Brazil. "The question is one that does not admit of an adequate answer except for the regions visited by the writer, which as already stated, include only, a portion of that great territory, and only the southern portion of Brazil; namely, the states of Rio Grande do Sul, Santa Catharina, Paraná, and a few rapid excursions across São Paulo, and Minas Geraes, as well as the brief visit to Marahú in Bahia. "That the sedimentary beds of the Brazilian Permian once held some petroleum is attested by the evidence of the Iraty black shale which gives off the characteristic odor of this substance from São Paulo to Rio Grande do Sul.

Jan 1, 1918

A new departure of unusual importance in Institute annals was in-augurated by the trip of President Philip N. Moore to the Local Sections at Nevada, Southern California, San Francisco, Seattle, Spokane, Montana, Utah, and Colorado. Everywhere the visit of the President was the occasion of an enthusiastic and successful meeting, which is reflected in the account, published under the different Sections in this and other Bulletins. The President also joined the members of the Columbia Section in their visit to Nelson, British Columbia, at the International Mining Convention, which was attended by mining engineers of Canada and the United States. The President of the Canadian Mining Institute, as well as the officers and members of the Western Section also attended this convention. For full particulars we recommend to our readers the ac- count of this very interesting meeting, which is given on another page of this. Bulletin. It is believed that this is the first meeting between the mining engineers of America and any other country since America joined the Allies. The Secretary of the Institute accompanied the President at the first four meetings and was expecting to attend the others also, but was called home by a death in his family.

Jan 7, 1917

By Robert Glass Cleland

IN gathering material for this book, I have made extensive use of the archives of Phelps Dodge, contemporary news- papers, and a wide range of secondary sources. Two manuscripts-one on the history of Phelps Dodge by Arthur Train, Jr., and John L. Lawler, the other a biography of William E. Dodge by Richard Lowitt-have been of the greatest value. I owe a particular debt to the authors whose names I have just mentioned. I have also gathered important information and obtained revealing points of view from conversations with many people. Personal visits to the company's mines and plants added knowledge and understanding that nothing else was able to supply. I am greatly obligated to the officers of the company, especially to Mr. Louis S. Cates, chairman of the board of directors, Mr. Robert G. Page, president, Mr. George R. Drysdale, vice-president of Phelps Dodge Corporation, and Mr. Walter C. Bennett, president of Phelps Dodge Refining Corporation, for their co-operation and assistance. Mr. Wylie Brown, former president of Phelps Dodge Copper Products Corporation, also supplied valuable data and deeply appreciated hospitality. In my visits to the Phelps Dodge properties, company representatives extended every hospitality and placed at

Jan 1, 1952

By Homer Turner

COALS, other than anthracite, have been so thoroughly studied under the microscope during recent years, that we now know what kinds of plants and what parts of plants form the bulk of lower rank coals from peat to bituminous coal. The microscope has also shown the state of preservation of such vegetation as well as the nature and distribution of products of plant decay. These and further details have been ascertained mainly through the employment of two methods of attack, section cutting and maceration. Anthracite has failed to respond to these methods, so well adapted to the study of lower rank coals and, therefore, has been neglected by investigators to such an extent that there is much doubt as to its microscopical characteristics. The object of this paper is to lift anthracite from its realm of obscurity by demonstrating the wealth of microscopical detail that is revealed when reflected light is used on a properly polished and etched surface and, further, to show the relationship between anthracite and bituminous coal.

Jan 2, 1925

By Dexter Kimball

THE ease and promptness with which the public as a whole becomes accustomed to and takes advantage of the work of the engineer, using the term in a broad sense, is almost startling. Surprise at, and fear of radical innovations in transportation and private service quickly give way to blasé indifference, followed instantly by all manner of criticism that these things are not better constructed and managed. Does the street car stop a few minutes on a switch?-summon the State Commission. Is the Overland Express fifteen minutes late on a three thousand mile run?-Congress is memorialized to make the great railroad companies attend to their business. Does central not respond instantly when we take down the telephone receiver?-anathema!! Do the electric lights go out for a minute or so?-the darkness is illuminated by caustic sarcasm and other kinds of spoken English consigning all engineering and engineers to perdition; everyone apparently forgetting how steep the hills were before the days of street cars, how far away San Francisco was before the days of the locomotive, the telegraph and telephone, and how difficult it must have been to study by the light of a tallow candle.

Jan 9, 1922

By Gerald Sherman

LARGE part of the mining industry is still under the shadow of the depression, and unwilling to undertake changes in plant or methods of operation that require large preliminary expenditures of money. Certain metals command fair prices: nickel, tin, and molybdenum. The precious metals, gold and silver, have been given greater values by natural processes of economics or by proclamation, but are of so much less importance in industry, in total value, and number of men employed, that they have not greatly raised the average for the mining business. The increased value of gold which was established in 1933 has stimulated .the search for new deposits, and aided efforts to revive some of the old mines 'Where it is hoped to find quantities of marginal ore now become profitable. The higher price did not increase production very much for 1934, but two discoveries of major importance, and others yet to be proved, will help later. The two referred to are the Lupa gold field in Tanganyika Territory, and the Silver Queen mine on Soledad Mountain near Mojave in California. The first was recently discovered, and is being developed by the East African Goldfields, Ltd. Uncompleted explorations of the croppings early in the year had exposed for measurement and sampling to a shallow depth, three ore shoots as gregating 7400 ft. in length and 6 ft. in width, containing 0.375 oz. of gold per ton. In the Silver Queen. an ore-

Jan 1, 1935

By William Campbell

(Cleveland Meeting, October, 1912.) THE structure of iron and steel, though the object of so much study and research for the past 25 years, is by no means thoroughly understood. In the first place, we have three or more distinct iron-carbon thermal diagrams, each with its own supporters, and each representing a theory of the structure and constitution of cast-iron. In the second place, by reason of the fact that austenite, the solid solution of carbon in iron, decomposes in the solid state into ferrite, or pure iron, and cementite (Fe3C), and that quenching from above this transition-range, no matter how rapid, cannot entirely prevent the change and thus preserve the austenite by itself at ordinary temperatures, it happens that under the microscope we find, in addition to the ferrite, Fe3C, and austenite, which the thermal diagram of steel requires, it series of transition-products with distinctive structures, to which have ,been given the names martensite, troostite, sorbite, etc. Now these transition-products, in addition to the solid solution, austenite, have been the source of much controversy, at times very bitter. One side would insist that, say, troostite was an entity, which the other side would deny, pointing out that it must be a transition-mixture, with a particular structure. That austenite was a solid solution of carbon in iron has been denied by one school ; we have been told that Fe24C dissolved both Fe3C and Fe, and thus gave rise to a whole series of quenching-products-all this in spite of the fact that no matter how the thermal diagrams differ in regard to cast-iron, they all agree in regard to the solid solution, austenite, for Fe24C finds no place on the diagram. Thus it happens that while the authorities fight both in regard to the iron-carbon diagram and the structures met with in hard- * Associate Professor of Metallurgy, Columbia University in the City of New York.

Dec 1, 1912

By H. C. Lay

No one who knows the conditions of altitude, difficulty of access, shortness of working-season, etc., under which the work of the U. S. Geological Survey in the Rocky Mountains is carried on, can fail to be impressed with the magnitude and accuracy of the results obtained. Yet, in the necessarily brief time given to any one district, maily minor features must remain unregistered. The purpose of this paper is merely to place on record observations, made during nearly eighteen years, of local phenomena in themselves unimportant, which, however, if collated with similar memoranda from neighboring regions, may lead to something of value. The Telluride quadrangle in southwest Colorado is a tract of fifteen geographical minutes on a side, the NW. corner of which is in Long. 108º W., Lat. 38º N. Topographically it is essentially a lofty horseshoe, some of the peaks of which rise more than 14,000 ft. above tide, the interior (with an average altitude of 9000 ft.) being the eastern edge of the rolling Colorado-Utah plateau, and, in its turn, deeply cut by the canons of the San Miguel river and its tributaries. The range-summits are mainly igneous rocks, partly intrusive (such as massive " stocks" and laccolites, left bare by superior erosion), but mostly bedded volcanics of an average vertical thickness of 3500 ft., which change with changing height from andesite to rhyolite. The lowest series of these volcanic rocks, known as the San Juan formation, lies conformably upon the sedimentary San Miguel conglomerate, which dips gently east., and is attributed provisionally to the

Jan 1, 1902

By Alvinus Brown Wood

THE ancient copper-mines of Lake Superior, having been destroyed or covered by-modern mining-dumps, are not accessible to the present inhabitants of that region, and, since no more are likely to be found, some account of those already discovered, from one who has seen them, may be acceptable to the Institute. Early in May, 1855, 1 took a party of men to open an ancient pit on the Quincy mine-location. Mr. C. C. Douglas was the Agent.," as mine-managers were then called on Lake Superior. The Quincy Co. had previously done work on a fissure-vein, several hundred feet west of the Amygdaloid lode (afterwards called the Pewabic lode), on which was the ancient pit herein described. It was at this pit that the Quincy' main shaft was subsequently stink. The ancient pit showed an apparent depth of about 4 ft., but when cleaned out it was shown to be 14 ft. deep, having been filled up by the sliding-in of material composed largely of broken rock, taken out in sinking the ancient shaft, and left near its mouth. Midway of the shaft, and below water-level, was found a scaffolding, of white-birch poles,- which had been used as a landing, to assist in removing the excavated rock. The shaft was 7 ft. in diameter. The excavation had been done by first building fires in order to disintegrate the rock, as was proved by the abundance of charcoal found; then breaking the softened rock with hammers of diorite, such as is found in the greenstone range on Keweenaw point. These hammers had about. the size of large paving-stones. Only broken ones were found, the whole ones having been doubtless carried away for other work, such as could be traced on the lode for a hundred feet or more to the south. At the place where this shaft was stink, barrel-copper (i.e.,

Mar 1, 1906

By E. C. Hopkinson, A. H. Youmans, R. A. Bergan, H. I. Oshry

A new log has been developed for quantitative formation evaluation which is based on a measurement of the length of time slow neutrons survive before they are captured in the rocks and fluids. The logging instrument employs a cyclically pulsed neutron generator and a gated scintillation counter which is synchronized with the source. The source emits short, intense bursts of 14 mev neutrons once every 1,000 microsec and is quiescent between bursts. During the period the source is quiescent, the detector is electronically actuated for two independent preselected intervals. A comparison of the counting rates during these two intervals gives a measure of the rate of decay of the slow neutrons and of the associated gamma radiation. The average neutron lifetime in most earth formations is in the range from 50 to 500 microsec. It can be measured during a continuous logging operation at conventional logging speeds. The design of the logging instrument is described and the results of tests are compared with theoretical predictiom. Formulas are developed which give the relationship between log response and formation properties. It is shown that the method is particularly sensitive to formation fluid salinity, and that salt water saturation can be measured accurately in either cased or open hole. The measurement can be made independent of borehole size, fluid type, casing and tool position in the hole by properly selecting the intervals during which the measurements are made. The results of tests with a prototype logging tool are given. INTRODUCTION A new nuclear logging system has been developed which employs the Accelatron,* an accelerator-type neutron source, and accurately measures formation brine saturation in an entirely new way. It has produced a type of formation log with better sensitivity, greater sampling depth and simpler quantitative interpretation than any other nuclear log thus far suggested. The new Neutron Lifetime Log* employs a pulsed electromechanical neutron source and a synchronously gated radiation detector. A prototype instrument has been field tested during recent months to demonstrate the operability of the apparatus and the feasibility of the method. Tests in wells and simulated boreholes have confirmed theoretical predictions and have shown that formation param ters can be measured independent of casing and other borehole parameters. Preliminary results of field tests have indicated that the log may have important and widespread applications. BASIC PRINCIPLE OF NEUTRON LIFETIME LOG The Neutron Lifetime Log is based on the fact that neutrons emitted by a source in a well are rapidly but not instantly captured by the material around the source. Their capture is a matter of statistical probability; the greater the number of capturing nuclei and the greater the "capture cross section", the greater is the probability that a neutron will be captured quickly. The average life of a thermal neutron in vacuum is about 13 minutes, but in common earth materials, the average neutron life ranges between extremes of about 5 rnicrosec for rock salt and perhaps 900 microsec for quartzite. The Neutron Lifetime Log responds to variations in this average neutron life. The theoretical basis for a log of this general type has been well understood by nuclear logging experts in many laboratories both in America and in Russia, and develop mental work along these lines has been in progress for many years. The Russian literature has reported both theoretical and experimental work1,2 but in this country there have been no published reports of progress toward a practical logging instrument. The logging instrument is designed to measure radiation produced by slow neutrons during selected intervals when no neutrons are being emitted by the source. The source is arranged to emit neutrons in bursts or pulses. During the quiescent interval between the pulses, it is possible to observe the exponential "decay" of the neutrons and the neutron-induced radiation as the individual neutrons progressively disappear due to capture by atoms in the formation or the borehole. When a short pulse of 14 mev neutrons is emitted by a source in a borehole, the individual neutrons are slowed to thermal energy within a few microsec. Thus, a cloud of "slow" neutrons is formed around the source within 10 to 50 microsec after the pulse. This cloud is most dense within a few inches of the source, and is progressively less dense out to a radius of about 3 ft, where radiation from the source is practically undetectable.

Jan 1, 1965

By C. M. Loeb, A. M. Gaudin, J. H. Brown

THE object of most size reduction operations in the mineral industry is to liberate the grains of valuable minerals in the ore from those of the gangue. This is usually accomplished by crushing and grinding the entire mass of ore until there is only a small probability that any single particle contains more than one mineral. During this size reduction only limited control exists over size or composition of the particles exposed to the breaking action, and there is no control over the paths followed by cracks generated during the operation. This lack of control usually results in overgrinding and in production of large quantities of very fine material. The first detriment, overgrinding, is costly in itself, but when combined with the second factor it is doubly so. Not only is the fracture of a free particle unnecessary—the fracture of these particles may also make subsequent separation operations difficult, inefficient, and wasteful. It has been pointed out' that if the object of size reduction is to liberate the valuable mineral component of the ore then, ideally, fracture should follow intergranular paths to the exclusion of trans-granular ones. This would result in liberation of the valuable minerals with as little size reduction as possible. This ideal comminution operation is referred to as intergranular comminution, and it was the object of the investigation to determine the extent to which it could be developed by heat treatments. There are many indications in the literature that heating rocks prior to crushing may be favorable. Reports by Holman,2 Yates3 and Myers' are pertinent. These investigators showed that heating certain rocks prior to crushing them did, in fact, improve their crushing characteristics in that fewer fines were produced, although the fact that intergranular comminution was being effected apparently was overlooked. In addition, Sosman noted that if there is appreciable anisotropism in the thermal coefficients of expansion of even a pure mineral, then considerable permanent separation of the grains of the rock can be expected as a result of heating the rock to a high temperature.' By the same token, if there are ap- preciable differences in the thermal expansion coefficients of the various minerals of a multi-component rock, similar results should be obtained by heating this rock. This has been tested, partially, by Brenner," who obtained patents covering the heat treatment of some pegmatitic rocks in order to facilitate comminution of these materials. It has also been demonstrated that this may occur in taconite." Also, the possibility of causing decomposition of one mineral in a rock as a means of promoting intergranular fracture has been considered. Seigle2 and Schiffman et al. have obtained patents on such processes as applied to calcareous iron ores. These reports all indicate that heat treatments prior to crushing may contribute materially to intergranular comminution, but they also indicate that no organized attempt has been made to determine the controlling factors of the method or to determine its applicability in general. The present article is a report on the initial phase of such an investigation. The authors have reviewed the claims of prior investigators and have attempted, also, to establish the factors that might determine the applicability of heat treatments in the mineral industry. In this work 2000-g samples of various rocks were heated in a small laboratory furnace and crushing and sizing operations were carried out in standard laboratory equipment. All samples of each rock were as nearly identical as possible in particle size, grain size, and composition and contained only lumps coarse enough to contain many grains each. Tests on Granite A number of tests were made on a coarse grained Finnish granite obtained in the form of coarse chips from a local monument yard. This rock exhibited little variation from piece to piece in either composition or grain size. The minerals contained were quartz, orthoclase, small amounts of hornblende, and minute quantities of mica. Grain size ranged from about 1 mm to about 3 mm. Temperature of the Heat Treatment: In some cases the granite was heated to a particular temperature and crushed, hot, immediately upon withdrawal from the furnace—in others the rock was allowed to cool before crushing, but without quenching to room temperature after heating. In most tests on granite the heating period was about 2 hr with the furnace at the highest temperature for about 1 hr. Cases in which these periods were varied greatly will be presented separately.

Jan 1, 1959

By AIME AIME

AT a joint meeting of the Tulsa Geological Society and the Mid-Continent Section of the A; I. M. E., held at Tulsa on March 21, the history of unit development in the Kettle- man Hills field was discussed. Robert C. Patterson? Super- visor for the U. S. Geological Survey at Taft, Calif., was the speaker. An abstract of some of his remarks follows: On July 1, 1923, curtailment agreement for two years was made between the operators of North Dome Kettleman and the U. S. Department of the Interior. In this it was agreed to consider a plan of unit development, or other cooperate method of developing the structure. As a result, Kettleman North Dome Association was incorporated in December, 1930, as a non-profit cooperative corporation under the laws of California. Approved in January, 1931, by California Oil and Gas Supervisor and by Secretary of Interior. On Feb. 10, 1931, it became an active organization through election of executive officers and eleven- directors. General manager chosen. Association started to function April 1, 1931. Assumed control of 10,800 acres of proved and semi-proved land, as shown in Table 1.

Jan 1, 1932

By Robert C. Emmett, Donald A. Dahlstrom

FOR many years gravitational classification has been employed as a basic tool in beneficiation of minerals and coal. While improvements have been made to increase efficiency and fields of application, the basic flow pattern has remained relatively unchanged in most gravitational classifiers. Feed slurry is introduced into a settling pool wherein the coarser solids settle against either an upward or horizontal fluid current, or a combination of both, and are withdrawn in a concentrated underflow stream. The finer solids below the classification point possess too low a settling velocity and thus are primarily swept out through a weir overflow by the bulk of the fluid. Because of its simplicity, efficiency, and low power and maintenance costs, gravitational classification finds a wide acceptance for separations in the range of 20 to 325 mesh. Two factors resulting from the basic flow pattern employed in gravitational classification present difficult problems for certain installations. If classification at 60 to 200 mesh of separation is desired, capacity in terms of gallons of overflow per minute per square foot of settling pool area must be low to allow required solids to settle to the underflow. If a thousand or more gal per min of feed slurry must be handled, either a very large classifier or a number of smaller units must be employed, taking up floor space and head room. Examples of this are the large classifiers, wetting tanks, or settling tanks used in the coal industry for recovery of process water from fine solids. Units as large as 50 or 60 ft in diam and 60 ft high, requiring substantial amounts of steel, are not uncommon. A second factor is the lack of self-regulation in gravitational classification. As overflow rate increases, mesh of separation increases correspond-ingly. This normally heightens difficulties of bene-ficiation. If a fine mesh of separation is required at varying feed rates, the problem is more than doubled in complexity. One of the primary advantages of gravitational classification is low power requirement. Gravity feeds or very low pressure heads are employed. However, fluid energy is still present in the inlet stream and provision must be made to dissipate it properly to obtain uniform upward or horizontal currents. Rather than waste this energy, it would be desirable to utilize it to secure a greater degree of self-regulation and simultaneously increase classification capacity per square foot of area. A free vortex could be realized by a tangential entry of feed, resulting in generation of centrifugal force to complement force of gravity in its action. With greater force it should be possible to gain finer separation at any overflow rate per square foot of settling pool area as compared with conventional gravitational classification. Furthermore, as feed rate increases, centrifugal force will also increase and at least partially offset faster currents sweeping solid particles to the overflow. A more stable classification point should result. The liquid-solid cyclone is the most common application of a free vortex in the beneficiation field.' Many previous papers have emphasized uniformity of flow pattern within the cyclone which is largely responsible for the sharp classification that can be obtained.'-4 If a free vortex can be maintained in a non-pressurized vessel with a free surface it may be possible to realize a third advantage of sharper classification. This open-top cyclone would then achieve a minimum energy loss comparable to that with conventional classifiers, and a mesh of separation coarser than 150 mesh, extending the range of application of the free vortex. This is not presently possible with ordinary cyclones. To test the applicability of the free vortex to gravitational classification, a 30-in. diameter open-top cyclone was constructed at Northwestern University. The cylindrical section was 30 in. high and the conical section included an angle of 60". The feed nozzle was a standard 4-in. pipe entering tan-gentially, with centerline 17 1/2 in. below the top of the cyclone. The conical section was flanged near

Jan 1, 1954

By E. R. Macgregor, J. Halpern

The kinetics of the reduction of cupric salts in aqueous solution by molecular hydrogen to metallic copper are described. The rate of reduction appears to be homogeneously determined and shows a marked inverse dependence on the hydrogen-ion concentration. Precipitation of copper is more rapid and complete in sulfate than in per-chlorate solution. A mechanism is proposed which accounts for this behavior. IN recent years a number of important hydro-metallurgical processes have been developed in which metallic salts in aqueous solution are reduced by gaseous hydrogen, usually at elevated temperatures and pressures, and thereby precipitated either in metallic form (e.g. Ni, Co, Cu) or as an oxide or salt of lower valence (e.g. VO, and VA).1 ; In connection with applications such as these, most of which involve heterogeneously catalyzed reactions, recent demonstrations"-" that salts of certain metals, e.g., Cu", Ag' , Hg" , and Hg,+ can activate molecular hydrogen homogeneously and thus catalyze hydrogenation reactions in aqueous solution, are of considerable interest. For example, cupric salts catalyze the otherwise slow homogeneous reduction of dichromate and ceric salts by hydrogen, i.e. Cr,O; + 3HL. + 8H1 ? 2Cr'- -- 7H,O [1] 2Ce ' ! H.. ? 2Ce" | 2H . [2] In perchloric-acid solution, where Cu" is not appreciably complexed, the kinetics have been found" " to be of the form -d [H,] _- k,[HJ [CU"]' dt -LCu+' l+ (k ,/k,) [H] [3] where, K = 1x10"' exp [—26,600/RT] 1, mole-' min-' ... [4] and (k ,/k,) - 0.25 at 110°C. This kinetic behavior suggests that the reaction proceeds by a mechanism involving the following sequence of steps kt Cu" +H1CuH' 4-HA [51 k., CUH + CU" ? + 2Cu f H' [GI 6Cu'+ Cr,07 + 14H'+ 2Cr- (¦ 7H,O + 6Cu" ['i] fast The catalytic activities of the undissociated cupric-sulphate and cupric-acetate complexes are somewhat greater (by factors of 6.5 and 120, respectively) than that of the simple hydrated Cu" ion.'" These considerations suggest that, in contrast to the other hydrometallurgical hydrogenation reactions, referred to previously, reduction of cupric salts in aqueous solutions by molecular hydrogen, should proceed homogeneously, and in the absence of an extraneous catalyst. This has already been demonstrated" for acetate-buffered solutions where the product of the reaction is a precipitate of cuprous oxide (Cu,O). In the present paper, an investigation of the reduction of cupric salts in perchloric-acid and sulphuric-acid solutions, leading to the precipitation of metallic copper, is described. Some results for the sulphate system, which is of considerable hydrometallurgical interest, have been reported previously by Ipatieff",' " and by Schaufel-berger' but these do not give a quantitative account, of the kinetics and mechanism of the reaction. Experimental The reduction experiments were conducted in the 1-gal, titanium-lined autoclave described in connection with earlier related investigations," " and using a similar procedure. The solutions were made up by dissolving known amounts of CP grade Cu(ClO,), and HC10, (or CuSO, and HISO,) in dis-tilled water. While in the autoclave, the solution was stirred and maintained at a constant temperature (±loc) and under a constant partial pressure of hydrogen gas. It was ascertained that the agitation (provided by two 3-in., four-bladed stirrers, rotating at 900 rpm) was adequate so that at no time was the rate of reaction limited by solution of hydrogen. During each experiment, samples of the solution were withdrawn periodically, allowed to cool, and the concentration of copper remaining in solution was then determined electrolytically. Some Cu' is formed during the reaction, but undergoes disproportionation when the solution is cooled to room temperature. For purposes of kinetic calcula-

Jan 1, 1959

By V. V. J. Sarma

Interpretation of earth resistivity data involves not only obtaining depth to interfaces but also determining the nature of formations from their resistivity characteristics. Moore's method of interpretation envisages obtaining depths to the interfaces alone. A simple method of estimating the true resistivity values of formations by applying Hummel's formula of average resistivities is proposed. The method would increase the interpretative value of Moore's method as originally proposed. For most of the earth resistivity measurements, the four-electrode configuration developed by Wennerl is employed. In principal, the method consists of energizing (Current I) the ground through two outer electrodes and measuring the resultant potential (v) between the two inner electrodes. The configuration is such that the separation (a) between any two successive electrodes is equal. The apparent resistivity (pa) for such a configuration is given by 2p- a (V/I). By increasing the electrode separation (pa vs a) curves are obtained. Ideally, a homogeneous isotropic formation underground has a characteristic resistivity. However, the field conditions do not present such ideal cases. Almost invariably, even in the same geological bed, the physical conditions are widely different at different parts in the bed. It is further shown that the penetration of the current into the ground for a given horizontal electrode separation, a, is roughly down to a depth, equal to a. It is therefore, evident that the apparent resistivity calculated from the field observations is a weighted average of the resistivities of the materials present down to this depth. With some prior knowledge about the relative dispositions of the geological formations and their physical conditions, it would be possible, by resistivity surveys, to obtain characteristic resistivities for these formations. It is, thus, that the apparent resistivity-electrode separation curves enable one to decipher the resis- tivity distribution at various depth levels and therefore the nature of the geological formations present. Both empirical and theoretical methods have been developed for determining resistivity characteristics of the various formations. The theoretical methods proposed by Tagg2 and Roman3 are derived from studies of the potential distribution on the surface due to the presence of layers of widely differing resistivities underground. The more recent methods of Wetzel and McMurry4 and Wetzel and Mooney5 are but extensions of the original Roman method of superposition. These methods suffer from lack of similarity of the actual field conditions with those of assumed conditions in developing the theory. The empirical methods such as the one developed by Gish and rooneY6 depend purely on personal observation and local peculiarities, and are applicable only for those limited areas. Out of the empirical methods, moore's7 cumulative resistivity method is still found to be applicable in several localities of differing conditions. While Reudy in 1945 adduced some theoretical justification for the method (Eve and Keys),8 Muskat9 and Mooney 10 tried to show the lack of theoretical basis for the same. It is, however, observed that the method in practice "forms a valuable means of successfully attacking the apparent resistivity curves which fail to respond to the Gish-Rooney, the Tagg or the Roman logarithmic methods" (Ramachandra Rao). 11 Comparatively good results are also reported by Melbyel2 by employing Moore's method in interpreting the resistivity results obtained for ground water in the city of Gunnison, Colo. MOORE'S METHOD As has already been pointed out, the application of the theoretical methods is time-consuming, laborious and sometimes not applicable for quick and accurate interpretation of the field data. moore7 has developed a quick method for obtaining depths to interfaces by plotting the cumulative sums of resistivities, against the corresponding electrode separations a instead of plotting the usual Pa — a curve. In this process of continuous integration, corrections for small variations in resistivities, arising due to local surface conditions or adjacent layers, are made, while large consistent variations are brought out

Jan 1, 1963

By Walter Miller

ALTHOUGH confident of its ability to meet any demands which may be made, the petroleum refining industry is not complacent about the situation and realizes that the quantities of petroleum products to be furnished are so enormous and so far beyond what was previously estimated that the full co-operative effort of the industry must be exerted. Establishment by the President in May of the Office of Petroleum Coordinator for Defense with Secretary of the Interior Ickes at its head, plus the formation of the Petroleum Industry Council for Defense, in November, provide the channels for united endeavor within the industry and the means for gearing that endeavor within the industry and the means for gearing that endeavor in full harmony with the nation?s needs. Great strides have been made and a rapid understanding of the situation and the magnitude of the task is being attained by all concerned.

Jan 1, 1942

By Robert L. Slobod

In much of the work reported in the literature on long cores. true connate water value, probably have not been obtained because of insufficient flow of 011 to attain equilibrium. A -.satisfactory method for establishing connate water in long cores has been developed in which oil flow is maintained until no additiona1 water is displaced. INTRODUCTION Long cores have been used by sev-erals investigators in an effort to evaluate the efficiency of oil recovery for various producing schemes. The effects of many variables such as rate of displacement. pressure drop, volume of displacing medium, gas-oil ratio, inter-facial tension, and others have been investigated, and the merits of gas drive have been compared with water drive. In the older experiments no connate water was used. but in the more recent stndies the philosophy of the experiment calls for a core containing oil and connate water (irreducible water) as the starting point of the experiment. The method generally used to establish this condition in long cores involves dynamic' displacement wherein one or more phases are forced through the core. flow being maintained at a constant rate or at a constant pressure until a steady state is reached wherein there is no change of saturation with time. It is one purpose of this paper to point out that in much of the work reported in the literature true connate water values probably have not been obtained. The reason for this failure is pointed out. and a method for obtaining more reliable connate water values on long cores is presented. It is impossible at this time to completely evaluate the effect on the conclusions in the earlier papers resulting from the failure to obtain true connate water in the long cores, but some data are presented which indicate that serious errors may he present in many cases. MATERIALS AND APPARATUS Cores cut front outcrop sandstones (Strawn. Torpedo, and Elgin sandstones) with permeabilities of the order of 300 md were used. The major experiments were made with a core 18-in. long and 2-in. in diameter. Cores of the same diameter but only 12-in. long were used in a few tests? and in some work a core I-in. in diameter and 11-in. long was used. These materials were all somewhat bentonitic. 'To reduce the effect of such constituents, one of the cores (Torpedo No. 10) on which the most work was performed was acid extracted at the start of the experiment. Brine containing 50,000 ppm chloride and naphtha (Stoddard's Solvent) were used as the water and oil phases, respectively. The core was mounted in a rubber sleeve which forms the inner lining of a brass cylinder. In this arrangement2 the rubber sleeve is forced against the core by applying pressure to water in the annular space between the rubber sleeve and the brass cylinder wall. The core is therefore sealed in rubber so that all fluids introduced at the input end of the core flow through the core. With this equipment the core may be easily removed for inspection and analysis. Also, other cores may be introduced for study with no extra time for preparation such as is required when plastic mounting is used. When pressure or conductivity measurements are desired at intermediate points along tile length of the core, the brass cylinder comprising the outer jacket of the core holder is cut into section, of the desired length. Each section is then made up as an individual unit with its own rubber sleeve (see Fig. 1). The individual units are then butted up against a ring of plastic or other insulating material which carries an electrical contact for resistivity measurements and an opening which can be used for the measurements of fluid pressures. The individual units are forced tightly against the plastic ring separators and held in place with several tie rods. Inlet and outlet end butts of the same diameter as the core and several inches in length are provided to control the introduction and withdrawal of fluids and to complete the arrangement for sealing the core within the rubber sleeve. Fluid flow is maintained either by applying pressure to the liquid confined in a reservoir or by the use of a gear pump. The latter is preferable where continuous flow at a moderate rate over a long time interval is desired since a small volume of liquid can be readily recirculated using filters to prevent plugging of the core. EXPERIMENTAL The oven-dried core is weighed and is then completely saturated with brine

Jan 1, 1950

By Roy J. Helfinstine

One of the most urgent needs in the field of coal combustion is the ability to predict the performance of a coal from knowledge gained from small-scale tests. Numerous types of analyses and tests are conducted on coal, including the proximate and ultimate analyses, heating value, varieties of sulphur, ash analysis, ash fusion temperatures, free swelling index, petrographic analysis, and Gieseler plasticity. The Illinois Geological Survey has made an intensive study of the value of these tests for judging the performance characteristics of the coal as actually utilized. To date, three reports 1 2 3 have been is- sued, and another is being prepared. The present paper briefly summarizes some of the results found in the studies.

Jan 1, 1949