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By R. H. Adams, A. M. Khan

The Huntington Beach oil field is on the Pacific Coast, southeast of the City of Los Angeles (Fig. 1). It lies both onshore and offshore. Most of the onshore section is operated by Standard Oil Co. of California, WOI. The Tar reservoir is of upper Pliocene age, about 200 ft thick, and consists principally of fine-grained, unconsolidated, somewhat shaly sand, with thin inter-bedded shale stringers throughout (Fig. 2). The reservoir is a broad, highly faulted, elongated anticline, with an areal extent of about 370 acres. Most of the faults bisecting the structure are normal, trend north-south, and are the main cause of reservoir discontinuity (Figs. 3 and 4). From 1964 to Dec., 1967, 259 steam stimulations were performed on a total of 125 Tar sand wells. Eighty-six new wells were drilled and steam stimulated. Of the total, 96 have been stimulated twice, 34 three times and 3 four times. During this same period, a two-injector steam drive pilot has been in progress. The response obtained from this project has been compared with the response to cyclic stimulation. This paper presents an analysis of the field observations for the two methods of thermal recovery. History of Development Drilling to the Tar pool commenced in 1924 with an initial well production of 40 to 50 B/D of 12o API gravity oil. Complete primary development of the pool has been spread over several years. Approxi- mately 40 wells were drilled during the first phase of development, which was completed in 1945. The subsequent primary development started in 1960 with initial well productions of 30 to 40 B/D oil. Thirty-seven wells were completed in the Tar pool during this phase. For the most part, slotted, gravel flow packed liners have been used in the wells in this pool. A cyclic steam stimulation pilot was initiated in March, 1964. Based on the very successful stimulation in the pilot area, the cyclic stimulation project was expanded to include all of the Tar pool wells producing at the end of 1965 (Fig. 5). Also, a development drilling program was begun at this time. To date, 86 new wells have been drilled under this program. The number of wells drilled each year in this secondary phase of development is also shown in Fig. 5. New Well Completion Practices Most of the new wells have been completed to produce from both the Upper and Lower Tar zones. Generally, a casing stub is cemented from the top of Lower Tar to the base of clean Upper Tar sands to exclude intermediate water-bearing sands. The water string is then cemented from the top of Upper Tar to about 1,500 ft with neat cement and 30 percent silica flour. The annulus from 1,500 ft to surface is then filled with a petroleum-based gel through a high-temperature port collar. Once again, a history of sand-free production dictated the use of 60-mesh gravel flow packed liners. The Upper and Lower Tar

Jan 1, 1970

By D. F. Hewett

CONTENTS PAGE Introduction 1 Geologic features of eastern Oregon 2 Geology of the Sumpter quadrangle 2 Rocks older than the ore deposits 3 Rocks younger than the ore deposits 8 Lodes of the Sumpter quadrangle 8 Areal distribution 8 Geologic distribution 9 Major features of the veins 9 Mineralogy and texture of the veins 13 Ore deposits zonally disposed around the Bald Mountain batholith . . . . 13 Summary of mineralogy and texture 32 Zonal relations 33 Ore deposits zonally disposed around Greenhorn Mountain batholith . . . 36 Zonal relations 37 Relation of textural features to zonal arrangement of veins 37 Summary of zonal relations 38 Comparison with similar districts 39 Outlook for the district 40 INTRODUCTION IN an earlier report on the Sumpter quadrangle1 it was briefly stated that the quartz lodes of that region might be separated into several groups or belts on the basis of the kind and abundance of the minerals of which they are composed, and that these belts were disposed as areal zones around the principal intrusive mass of the region. When the opportunity to revisit the region was offered in 1929, as a result of a cooperative agreement between the State Mining Board of Oregon and the United States Geological Survey, it seemed advisable to pay particular attention to this feature of the lodes, in the hope that if the idea of zonal relations was confirmed it might serve as a guide in exploitation.

Jan 1, 1931

By H. P. Stüwe

HE recent papers of Aust and Rutter112 have again brought to mind the importance of certain "special" orientation relationships between the lattices of two fcc crystals on the mobility of the grain boundary separating them. No theoretical treatment of this problem has been offered till now. The only principle published so far that has given an indication why certain orientation relationships should be "special" is the counting of "coincidence sites" according to the suggestions by Kronberg and Wilson.3 The "coincidence plots" published by these authors show, for instance, that two fcc lattices rotated by 38 deg around a common (111)-axis have 1/7 of their lattice sites in common. Such an orientation relationship is also characteristic for high boundary mobility. The accuracy of the orientation relationship needed for high mobility is not too rigid. Deviations up to 10 deg from the ideal orientation seem to be tolerable as can be gathered from the experimental data.'j4 The auestion arises, then. how the density of coincidence sites will be affected by a deviatioi from mathematical accuracy. This can be checked by a simple model. Two sieves are prepared, the arrangement of the holes corresponding to lattice sites on a (111)-plane in a fcc crystal. They are placed upon each other, Fig. 1. One is kept fixed, the other is rotated around an axis pushed through one hole in common to both. The light falling through holes of both sieves is then a measure for the density of coincidence sites. If the diameter of the holes is very small, light intensity is contributed only by holes the centers of which coincide "exactly." If the diameter of the holes is rather large, some intensity will be contributed by

Jan 1, 1962

Organization Place Date 1918 American Society of Mechanical Engineers...:.. Worcester, Mass. June 4-7 American Institute of Chemical Engineers Berlin, N. H. June 19-22 American Concrete Institute Atlantic City, N. J. June 24-26 American Society for Testing Materials Atlantic City, N. J. June 25 28 American Institute of Electrical Engineers Atlantic City, N. J. June 26-28 New York Electrical Society, Annual Meeting... New York, N. Y. June American Institute of Mining Engineers Colorado Sept. 2-7 National Association of Stationary Engineers.... Cincinnati, 0. Sept. 9-13 British Iron and Steel Institute, Autumn Meeting London, Eng. Sept. 12-13 National Exposition of Chemical Industries New York, N. Y. Sept. 23-28 American Chemical Society Cleveland, 0. Sept. National Petroleum Association.: Atlantic City, N. J. Sept.

Jan 6, 1918

By J. E. Forciea, O. E. Palasvirta, L. G. Hendrickson

AH pilot and commercial plants working with Mesabi Range taconite employ wet magnetic separation. Progress is being made with a dry magnetic process, but this has not yet been applied to taconite except in the laboratory and pilot plants. Flowsheets in all five plants are similar, including multiple stages of grinding, each followed by magnetic separation, which rejects a finished tailing. The flowsheet in Fig. 1 is used in the preliminary and commercial plants of the Erie and Reserve mining companies and in Unit C of Oliver's Pilotac plant. At Erie the desliming operation is omitted. In the Reserve plants two ball mills are used with each rod mill. Pilotac uses flowsheet 2 in Unit A-B and has also tested flowsheet 3. Principal differences in the three flowsheets are the number of grinding stages and the type of roughing. The terms open-circuit roughing and closed-circuit roughing are best defined by the diagrams. Special Test Data Given in Table I: For the Erie and Reserve commercial plants, Table I reflects routine conditions. Pilotac, the experimental plant, has been run with several flowsheets, including those followed at Erie and Reserve's commercial operations. Pilotac data for these last two flowsheets are similar to commercial plant results and are not repeated in Table I; statistics are given, however, for special test conditions. using other flowsheets. when the objective was to 'to extra-grade concentrate, Variations Among Taconites: Although crude ore tributary to these plants is generally classified as taconite, there are important differences in mineralogy and fineness of dissemination.

Jan 1, 1959

By Eugene Stephenson

CRITICAL analyses of the work expended in producing oil by the utilization of gas energy have appeared in the publications of Shaw,1 Pierce and Lewis,2 and Herold,3 authors who have ably discussed the factors which must be taken into consideration in comparing energy consumed per barrel in various wells which are flowed by means of gas-lift. However, two distinct phases of oil production are concerned with the ratio of gas energy consumed to oil produced. One of these phases is the gas-lift, which utilizes the differential gas pressures for the purpose of flowing oil, whether these pressures be natural reservoir pressures or be induced by artificial compression of gas or air. The other phase has to do with prorating oil production in pools which are operated either as units, or are subject to such restrictions as those imposed at Oklahoma City by the Corporation Commission, or, by similar controlling groups in other fields. An abundance of literature is available relative to the problems of flowing wells by gas-lift, but the first suggestion that the energy of the gas within the oil and gas pool might serve as a basis for proration, appeared in the timely article by McWilliams.4 Much of the. dissatisfaction with proration in certain fields is because some operators feel that besides the hazard to the wells which accompanies the test, the method of allocating production on the basis of the "potential" gage is inequitable and gives some operators a distinct advantage over others.5 The most severe penalty may be exacted from the most progressive operators or those who attempt to produce their oil with a minimum quantity of reservoir gas. If :no difficulties ever

Jan 1, 1931

By George Comstock

IT seems a common opinion among metallographists that all light-gray inclusions seen with the microscope in polished sections of steel are manganese sulphide. Examples of this belief are continually appearing, as for instance in the paper by Dr. Henry Fay on manganese sulphide as a source of danger in steel rails,1 and in Lieutenant-Commander Cook's paper on Metallography of Steel for U S. Naval Ordnance.2 Slate FIG. 1-TRANSVERSE VIEW OF THE EDGE OF A SMALL HOT-ROLLED STEEL ROD. ETCHED WITH PICRIC ACID. X 200. colored inclusions are considered to be silicates, and dove-gray inclusions, manganese sulphide. To show the danger in the latter unqualified assumption, it should be sufficient to examine the edge of any piece of steel that is covered with a fairly thick scale, and that has been polished in such a way as to prevent the scale from breaking away entirely below the polished surface. This can be done by protecting the scaled edge of

Jan 12, 1916

COUNCIL OF ECONOMICS OF AIME Formerly Mineral Economics Division Established as a Division December 15, 1948 Established as a Council February 26, 1957 Franz R Dykstra, Chairman Paul Schultz, Vice-Chairman A J Phillips, Vice-Chairman Douglas Donald, Vice-Chairman J S Vanick, Contact AIME Director A H Lindley, Jr, Secretary-Treasurer Lehman Brothers 1 William Street New York 4, N Y COUNCIL OF EDUCATION OF AIME Formerly Mineral Industry Education Division Established as a Division January 15, 1932 Established as a Council February 26, 1957 0 Cutler Shepard,Chairman Lysle E Shaffer, Vice-Chairman John C Calhoun, Jr, Past Chairman J C Kinnear, Jr, Contact AIME Director J D Forrester, Secretary-Treasurer College of Mines Univ of Arizona Tucson, Arizona

Jan 1, 1958

By Ernst M. Cohn

The demonstrations of the "Silent Sentry" by Union Carbide Corp. in 1957 and of a special tractor-plow by Allis-Chalmers in 1959 ushered in the technology era of fuel cells. The idea for direct conversion of chemical to electrical energy, first published in 1801 by Davy in England and Ritter in Germany, has been kept alive by a few people through 150 years: Grove built the first hydrogen-oxygen fuel cell in 1839; Mond and Langer made electrolyte contributions around 1890 that are still used today; Baur worked on coal-based cells from 1900; Bacon started his work in the '30's, which resulted in the first multi-kilowatt unit in the '50's; Davtyan studied molten-salt electrolytes in the '40's, followed by Ketelaar in the '50's; and Justi developed highly active electrodes in the '50's, to name only some of the pioneers. Despite the tremendous increase in research and development of fuel cells, these direct energy converters are still in their infancy. They will find their functional application in space, where power density must be maximized and product water utilized. These early systems will provide valuable experience in system engineering and reliability.

Jan 9, 1964

By J. D. Allen

In the coal preparation plant at U.S. Steel Corp.'s Concord mine in Alabama, the product moisture was reduced from about 20% to 9% through the development of a workable flowsheet for dying the clean coal. Some of the high points of the conversion of the Concord washer from vibrating screen dewatering to centrifuge drying are presented in this article. The coal preparation plant at the United States Steel Corp.'s Concord mine near Bessemer, Ala., began operations in June, 1950. The basic cleaning circuit consisted of a Chance cone for cleaning the 2-in. x 3/8-in. fraction and concentrating tables for cleaning the -3/8-in. coal fraction. Dewatering of the final product was accomplished with 35-mesh vibrating screens. However, because Concord coal is very friable with 85% passing 3 mesh and 25% passing 28 mesh (Fig. I), a considerable quantity of fines passed through the dewatering screens. To recover these fines, the dewatering screen effluent was sent to two 70-ft-diam hyd rose para tors from which the underflow returned to the dewatering screens and the overflow went to a 175-ft-diam thickener for water clarification, as illustrated in Fig. 2. As might be expected, there was considerable recirculation of the -35-mesh coal in this system. This degraded the coal and led to higher moistures. It also resulted in a fines bleed-off of plant water and thickener underflow to a fine-coal settling pond. In 1961, vacuum filters were installed to supplement the screens and to recover the fine coal lost in the bleed-off. The above system resulted in a product moisture of about 20%. Further reduction to approximately 11% was accomplished by drainage from railroad cars during transit to the coke plant. Control of the moisture at unloading was poor because of variations in operating levels and railroad car availability, but since the Concord coal constituted a relatively small percentage of the over-all coal mix at the coke plant, its high moisture and fluctuations did not seriously hamper coking operations. Early in 1964, however, the proportion of Concord coal was increased with a resulting increase in the moisture of the total coal mix, and this caused difficulties in the coke plant. The increased participation of Concord coal also brought about a shortage of railroad cars which raised the moisture content to a point where the coal became almost impossible to handle. In an effort to alleviate this problem, U.S. Steel initiated a research program to develop a flowsheet for reducing the moisture to approximately 10% and to determine whether the resulting product would be satisfactory for the coke plant. Under this program, an experimental flowsheet for evaluating both a vibratory centrifuge system and a solid bowl centrifuge system was drawn up as shown in Fig. 3. A horizontal vibratory centrifuge was installed to reduce the moisture in the dewatered coarse coal, and a four-cell, flotation machine was installed to clean the -65-mesh portion of the 3/8-in. x 0 table raw coal feed. Several shortcomings in the above circuits were apparent. For one thing, large quantities of repulping water were required. Furthermore, since about half of the flotation feed was of a size consist that could have been cleaned on the tables, these circuits would result in an unnecessary increase in reagent costs and facilities. Maintenance of the hydro separators and pumps for pumping the underflow to the filters,

Jan 1, 1969

By Charles H. Jacoby

The solution mining of evaporites has a history of approximately 5,000 years. The insitu leaching of metalliferous ore will have many of the same characteristic problems which have confronted industry for years in the production of evaporite minerals. Basically we will be converting the less soluble forms of valuable metals into their more soluble salts and producing these in much the same manner as, for example, sodium chloride. There are a number of problems which we are faced with that are more complex and complicated and, therefore, will require a higher degree of sophistication than previously employed. One of our most important undertakings will be the clearcut definition of the problems involved. While a great deal of expertise can be drawn from the solution mining of evaporites and the oil industry, problems peculiar to the hydrometallurgical field will need to be solved. One of these is the introduction of permeability into an impermeable rock so as to expose the sought after values of metals which by volume are infinitesimal when compared with sodium chloride, potash or other type water soluble mineralization. After establishing this permeability which will be miniscule when compared to a solution cavity, there will be the maintenance of this permeability. In general, salt deposits are of a somewhat uniform chemical composition and thus their chemistry was relatively simple. Each metalliferous ore body is somewhat unique in its chemistry and will need to be treated accordingly.

Jan 1, 1974

By S. P. Holt

The chief use of scrapers at this mine has been on lead ore of milling grade, clean and dry, in stulled stopes, 50-100 ft. long, 5-12 ft. high, and pitching 20-30°. Scrapers have also been used to fill these stopes with waste. The first scraper used (Fig. 1) is modified from a Cleveland-Cliffs design, being only 30 in. wide. It is light, weighing but 95 lb., handles well, and-digs itself in; but it spills part of its load on a long haul. It could be improved by lengthening the side plates, but because of the double bent angle irons, it is difficult to make at mine shops and has been discarded. Fig. 2 shows where the light angle irons have failed, spoiling

Jan 1, 1923

By S. P. Holt

The chief use of scrapers at this mine has been on lead ore of milling grade, clean and dry, in stulled stopes, 50-100 ft. long, 5-12 ft. high, and pitching 20-30°. Scrapers have also been used to fill these stopes with waste. The first scraper used (Fig. 1) is modified from a Cleveland-Cliffs design, being only 30 in. wide. It is light, weighing but 95 lb., handles well, and-digs itself in; but it spills part of its load on a long haul. It could be improved by lengthening the side plates, but because of the double bent angle irons, it is difficult to make at mine shops and has been discarded. Fig. 2 shows where the light angle irons have failed, spoiling

Jan 1, 1923

By Richard H. Mote, W. C. Schroeder

The endlessly changing pattern of mineral supply and demand offers opportunity to the alert and can bring disaster to the unwary. The discovery of ore bodies, the invention of extractive processes, the provision of new transport facilities, the political stabilization of underdeveloped areas, and many other changes can increase supply dramatically. Such new outpourings of mineral wealth from ore bodies bring fortunes to their developers, and consumers frequently find their competitive positions decidedly improved by new and cheap sources of supply. On the other hand, operators of marginal properties can find competition from newly opened high-grade mines intolerable. Consumers that have depended on the products of nearby, high-cost mines may find new, remote, low-cost supplies advantageous only to their competitors. The invention of new prospecting methods can have spectacular effects. Shortly after World War I the discovery rate of petroleum pools began to decline. The leading prospecting technique of that day, the projection downward of surface reflections of geologic structure, was proving less rewarding. Prophets foretold an oil shortage in the near future. But at that very moment scientists were perfecting the application of seismic waves to reveal underground oil-bearing geologic structures. As these geophysical methods were put into commercial use the whole outlook changed-the problem of the 1930's became how to cope with the surplus from discovery, not how to meet the ever rising demand. Many lead mines were being abandoned as unprofitable about this same time because the penalties charged by smelters for the zinc in the ores and concentrates more than counterbalanced the payments for lead and silver. Then selective flotation (at the time called differential flotation) appeared,

Jan 1, 1959

By C. O. Lee, Z. W. Bartlett, R. H. Feierabend

The Grand Isle sulfur mine is located in the Gulf of Mexico, approximately seven miles off the coast of Grand Isle, Jefferson Parish, La. The deposit is on acreage covered by oil, gas, and mineral leases originally issued in favor of Humble Oil & Refining Co. by the State of Louisiana which were continued, maintained, and redesignated by the U.S. Department of the Interior after passage of the Outer Continental Shelf Lands Act. The sulfur deposit was discovered in 1949 when Humble Oil & Refining Co. penetrated more than 200 ft of sulfur-bearing limestone in a zone between 1813 and 2075 ft below sea level. In 1954, Humble drilled ten more sulfur prospect holes, eight of which encountered sulfur ore. On September 19, 1956, Freeport Sulphur Co. acquired from Humble Oil & Refining Co, the sulfur rights underlying the tracts, and the actual design of the installation began the same month. The first structural contract was awarded in December 1957 and offshore erection began in June 1958. The initial phase of construction has been completed and production by the Frasch process commenced in April 1960. The estimated total cost of the project is $30 million, of which $8 million is the extra cost incurred by the necessity of offshore operations. More than $22 million was expended before production was started. GEOLOGY OF DEPOSIT Grand Isle is the third largest sulfur deposit in the U.S. The orebody embraces several hundred acres, but its outer limits are yet to be defined to the northeast, east, and south. Most Gulf Coast sulfur deposits occur in a caprock mantle of calcite (referred to as limestone), anhydrite, and occasionally gypsum, which covers the apex of an intrusive mass of salt. Commercial quantities of sulfur are usually confined to the calcite or limestone member. Most often such limestone is completely enclosed by dense anhydrite below and impervious sediments above, which effectively form a closed reservoir. The depth of the Grand Isle orebody ranges from 1800 ft to 2500 ft below sea level. Within the present boundary, the sulfur-bearing limestone varies in thickness from 220 ft to 425 ft, while the sulfur content varies an average of about 15 pct in the leanest hole to an average of about 30 pct in the richest. Rock containing less than 5 pct sulfur is not classed as ore, and holes assaying less than 20,-000 long tons per acre of sulfur in place are not considered commercial offshore. The sulfur enrich-

Jan 1, 1961

By L. H. Simons, H. H. Spain

I NT RODUCTION Theory indicates that linear water-floods should exhibit scaling and stabilization properties in both oil-wet and water-wet porous media'. Experimental verification of these proper-ties in oil-wet media was obtained some time ago', and more recently, Perkins', employing a high permeability unconsoli dated sand and a low oil-to-water viscosity ratio, has obtained flooding data in a water-wet medium which follow the pattern of scaling and stabilization. Also, Root and Calhoun3 have found similar trends in the displacement of gas by liquids from unconsolidated sands. In general, however, the experimen-tal evidence appears still somewhat conflicting since scaling and stabilization of water floods in water-wet media has not been observed in most of the studies to date'.".'. The purpose of this paper is to provide a more comprehensive picture of waterflood behavior in water-wet media and to corroborate the validity of the scaling and stabiliza-tion concepts. The need for differentiating between the intrinsic nature of water-oil displacements inside a porous medium and perturbating secondary end effects is discussed, pertinent experimental procedures are outlined and the results of flooding tests conducted at low and at high oil-to-water viscosity ratios on con- solidated, water-wet Alundum cores are analyzed. END EFFECTS IN WATER-WET MEDIA Outlet End Effects The peculiar feature of the outlet end effect in water-wet cores is that it not only results in an excessive wetting phase saturation at the outflow face,'.' but that it also retards the moment of water breakthrough: i.e., causes an undue delay in the appearance of water in the produced effluent. Conditions existing in a water-wet core when water first arrives at the outflow face are schematically shown in Fig. 1. At this flooding stage the saturation distribution, Fig. la, has not yet been distorted by the outlet end effect. A water-invaded pore at the outlet core face, opening into the oil-filled void space between the end of the core and the end plate of the flooding cell, is illustrated in Fig. lb. The curvature of the water-oil interface is concave toward the outlet, and the pressure on the water side of the interface is lower than on the oil side by an amount equal to a certain capillary pressure (Fig. lc). Before the water (of this particular pore) can be produced from the core, it is apparent that the pressure in the water phase must exceed that in the oil outside the core. Accordingly. when water first reaches the outlet face, it will not leave the core but will accumulate inside, and only oil will be produced. Eventually, as the water injection is continued. sufficient pressure is built up in the water to reverse the curvature of the interfaces in the outlet pores, and only then will water be produced from the core. This stage, illustrated in Fig. 2. corresponds to the conventional "water breakthrough" observed in flooding experiments. For purposes of discussion, it is convenient to distinguish between the flooding stage at which water first arrives at the outlet face of a core (Fig. 1) and the stage at which water is first produced from the core ( Fig. 2). The former will be referred to as "water arrival" and the latter water breakthrough. In oil-wet media

By P. Sanchez-Mejorada

GEOLOGISTS who are acquainted with the mines of northeastern Mexico realize that the most important lead-silver replacement deposits of the province are confined to a single formation. But since the formation is several hundred meters thick, the author has determined the relative position of the lead mantos in the belief that this information will prove useful in the search for new mines. This article describes the stratigraphic location of lead-silver replacement deposits known in several mines situated in a region comprising part of the states of Coahuila and Nuevo Leon. The area studied extends for 200 km* (125 miles) from east to west and 70 km (45 miles) north to south. Metallogenic Province: The most important metallic deposits of the region have the following common characteristics: 1) The orebodies occur as manto replacements of calcareous sediments. 2) The horizons that have contributed large tonnages of ore are in similar positions in the corresponding stratigraphic columns (as it will be shown later on). 3) Lead is the most important metal in the ores. Silver is commonly present in small amounts. Occurrence of zinc is dependent on the degree of oxidation of the primary sulfides. 4) A large proportion of the total production has been in the form of oxidized ores. 5) The deposits are located on anticlines. Rocks of Cretaceous age crop out over large areas of the states of Nuevo Leon and Coahuila. forming part of a belt that extends to the south along the eastern Sierra Madre. The sediments are cut by a small number of intrusive stocks ranging in characteristics from rhyolite to diorite. The most prominent structural feature of the region is a series of folds trending northwest-southeast. Faulting is not conspicuous in the region, although a major fault zone is found farther East.' The physiography closely reflects structural features, with mountains formed by anticlines and valleys conforming with intermediate synclines. Narrow valleys have also been developed along the axes of many anticlines, where solution of limy sedi- ments and erosion have proceeded along axial tension fractures. Stratigraphy: Rocks of the Upper Cretaceous are exposed in only a small percentage of the total area. Generally they have been eroded away from the mountains and are covered by recent talus and alluvium in the valleys. Humphrey' has published an excellent paper describing the Cretaceous formations of the Sierra de los Muertos, a short distance west of Monterrey. A brief summary of these formations is given below to convey an overall picture of the stratigraphic sequence that prevails just south of the area under consideration. Upper Cretaceous Indidura: Essentially thin shaly sediments. Cuesta del Cura: Limestone in thin wavy beds

Jan 1, 1959

By W. A. Krivsky, R. Schuhmann

Jan 1, 1962

By R. S. Olson

An analysis of the wash thickener-two stage filtration circuit was undertaken to quantitatively describe the circuit performance. On the basis of information developed in this study, the factors of major importance in reducing soluble loss are: filter wash, wash zone size, filter capacity, filter feed pulp dilution, blow back, filter cloth, water to repulp, water to primary wash, water to feed pulp and thickener underflow. The wash thickener-two stage filtration circuit has been used in many hydrometallurgical plants to separate solute from leach solids. As many as 20 to 30 plant operating variables determine the performance of the wash circuit and hence the soluble loss. The complex relationships of these variables, with each other and with soluble loss, make the evaluation of their effect on mill performance difficult. An analysis of this type of circuit was undertaken to quantitatively describe the circuit performance. THE CIRCUIT The diagram in Fig. 1 represents the operation of the wash thickener-two stage filter circuit. This circuit provides for counter current, cross current or for a combination of countercurrent-cross current operation. The feed pulp stream, J, is intended to include any solution or water, other than primary and secondary filtrate, which enters the wash thickener. Except for filter washing, the operations in the circuit are simple mixing operations which can be described by material balance. The concentration of solute in the filtrate and cake solution after application of wash liquor cannot be described by simple material balance. The displacement washing equation, derived by Rhodes1 and extended by Choundhury and Dahlstrom,2 appears to best describe this case of miscible displacement in porous media. In a useful form, it is

Jan 1, 1963

By Jerome F. Kuzmick

Condusions. From the work on aluminum powder, the following general con clusions can bc drawn: I. The physical properties of aluminum compacts, such as density. strength and ductility, increase with increasing pressure, up to the practicable pressure limits. 2. Good properties ill aluminum con pacts can be secured only by the use of high pressures, because it is neccssary to rupture the refractory oxide film on aluminum powder. 3. Considerable softening of the specimens occurs upon sintering. regardlers of the pressure used. General Conclusions 1. For relatively short-time sintering. molding pressure is a very important factor in the final physical properties of the sintered specimens. 2. The effect of pressure. is difierent for each metal, so that few general rules can be drawn that would apply to all metals. 3. In many cases, fur a particular metal powder and sintering temperature there is a critical pressure at which the best physical properties can be obtained. 4. The principles of cold work and in nealing and their effect on grain structure applied to massive metal also holds true for sintered metals. 5. Particle size, at least for electrolytic iron powder, does not have a. great effect on ultimate grain six. DISCUSSION [E. E, Schumacher presiding V.. V. Crane. *—I was particularly impressed with Dr. Kuzmick's work on tin IF not the illustration, particularly the Second one. a very good illustraition of hot preessing. in that

Jan 1, 1945