Search Documents

By R. L. Stone

None of the currently used methods of testing bentonites as binders for strengthening iron ore pellets is entirely adequate by itself. Since more knowledge was needed about 1) which properties of bentonite most affect pellet strength, and 2) the precise mechanism by which strengthening is produced, attention was paid to possible new techniques for rating bentonites. With the structural nature of bentonites — in particular, the montmorillonite component — the possibility of rating bentonites on the basis of zeta potential was investigated. These bentonites were also rated by conventional tests and measurements, including colloid content, barrel yield, pH, chemical analysis and physical tests on green and dry pellets. A mechanism for pellet bonding based on electro-kinetic forces between the bentonite and the iron ore concentrate appears to be feasible. In pelletizing, from 6 to 18 lbs of bentonite is added per ton of concentrate to give strength to the green and dry pellets. In some operations even more bentonite than is required for strengthening purposes must be added for moisture adsorption to pennit balling of the concentrate. Since bentonite is thus a major item in pelletizing, more knowledge about the way in which bentonites act as binders and better ways of rating this ability would help in the difficult job of selecting the right bentonite for a given concentrate. The fact of the matter is that although several methods are in current use for testing bentonites, none of these methods are consistently foolproof. For example, a given bentonite may rate high by several standard tests yet turn out to be a poor binder, and of course the reverse also occurs. Actually, more knowledge is needed about 1) which properties of bentonite most affect pellet strength, and 2) the precise mechanism by which strengthening is produced. In this study attention is therefore paid to possible new techniques for rating bentonites. With the structural nature of bentonites as a starting point, we investigated the possibility of rating bentonites on the basis of the zeta potential, i.e., the electrokinetic ootential on the montmorillonite colloids — the main component of bentonite binders. The zeta potential technique was applied to a range of commercial bentonites from several areas in the U.S. and abroad. These bentonites were also rated by conventional tests and measurements, including:

Jan 1, 1968

By Boris J. Kochanowsky, Burke O. Trafton

Because of the strict requirements on the quality of limestone that are dictated by the users, the operator was compelled to find new approaches to produce a product of uniform and acceptable quality. The raw material is controlled and monitored every two minutes by a special computer in order to ensure its quality. The required minimum and maximum quality constraint had an adverse effect on performance and consequently cost. In order to improve this performance, a Monte Carlo simulation model was developed and tested for the optimal truck allocation. The input data is based upon the distribution of equipment performances and costs.

Jan 1, 1969

By J. A. Herrick

Jan 1, 1879

By H. Matlock

Beam-columns with continuous or discontinuous transverse and angular loads and elastic restraints are represented mathematically in a manner corresponding to finite-element mechanical models. Solutions for linearly elastic cases are accomplished by direct recursion-equation elimination of unknowns, and for cases involving nonlinear loads and supports, by repeated trial-and-adjustment of complete elastic-type solutions. Five practical applications are presented by which various capabilities of the general method are illustrated. The examples include simulation of a pipeline launching and the bending and collapse of a conductor pipe in deep-water drilling operations. INTRODUCTION The diversified and complex operations being conducted in support of the production of offshore oil have produced a wide variety of new problems in structural mechanics. Many of these problems cannot be solved by conventional analytical or experimental approaches and have therefore stimulated inquiry into new methods of solution. It is the purpose of this paper to give a brief description of an analytical method for solving nonlinear beam-column problems and to illustrate the generality of the method by applying it to several problems related to offshore operations. Although the data for all of the examples are artificial, the cases discussed will be recognized as being based on actual situations. DESCRIPTION OF METHOD The analytical approach which is to be described stems from research on offshore foundations, in particular, the study of lateral-load behavior of foundation piles. The method represents a generalization of a technique which was suggested by Gleser' and extended by Focht and McClelland2 and Reese and Matlock." To maintain generality and therefore versatility in the method, a considerable variety of input data is considered. Fig. 1 illustrates the various types of loads and restraints which might be applied to a short segment of a beam. Each of the terms illustrated in the figure is shown acting in a positive sense. Capital letters are used to designate concentrated quantities whereas the corresponding lower-case symbols indicate effects which are distributed in some way along the length of the beam. The transverse loads and the elastic restraints may be divided into two classes: (1) loads Q and q and springs S and s, which act normal to the axis of the beam, and (2) couples T and t and rotational springs R and r, which act in an angular sense. In addition, there is an axial force P which may be constant or may vary along the length of the beam. The bending stiffness of the beam (the product EI of the modulus of elasticity and the moment of inertia) is designated by the symbol F. The assumptions of conventional elementary beam theory provide the basis for the present method. Among these are the neglect of shearing and axial deformations and the limiting of consideration to straight beams of symmetrical cross-section. Lateral deflections are considered to be small compared to original dimensions. A deformed element of such a beam is shown in Fig. 2a. The curvature of the beam is approximated by the second derivative of the deflection y with respect to distance x along the beam. It is assumed that the material of the beam is linearly elastic and therefore the relation of Eq. 1 between curvature and bending moment M is the ordinary expression from elementary beam theory. A generalized beam element is shown in Fig. 2b. The element has been deflected in a positive direction by an amount y and tilted through a small positive angle dy/dx. The various loads and elastic restraint reactions are detailed in the figure. Temporarily, only distributed effects are considered; provision for concentrated loads and restraints will be made subsequently. Eq. 2 in Fig. 2b is obtained by summing the forces and moments acting on

By DAVID F. McFARLAND

THE making of courses of study and curricula has long held first place as the favorite pastime of educators. As a game, this activity is as fascinating to some as golf or bridge, 'and the golfer's hope of a low score is matched by the teacher's ambition to some day evolve a sequence of studies that shall prove the ideal preparation for a life of maximum service and, profit. There are few in, this gathering who have not tried their skill at this game and still fewer are those who have been long satisfied by the product of their efforts. A curriculum is hardly printed in the college catalog before conditions arise which seem to make changes desirable, and strong will power is needed to maintain the program long enough to give it a fair trial. Metallurgical curricula are not less subject to change than others, 'and; indeed they have seemed, at times, to change more rapidly than other curricula because of the changing 'needs of the industries and the demand that the graduate be trained to meet the new conditions. Metallurgical practice is constantly proving that "time makes ancient good uncouth," and the graduate metallurgist is required to adapt himself to newer and

Jan 1, 1930

By S. M. Shelton

SINCE the Saar started. the real progress in scrap-metal recover is in the change of point of view regarding secondary metals. The tendency had been to regard scrap as the normal outgrowth of obsolescence, fluctuating somewhat from periods of depression to periods of prosperity. but nevertheless an unwieldy economic factor more to be contended with than embraced. Now, metals above the ground are being looked upon as semi-permanent reserves or stock piles in various stages of repeated use or revolving life cycles. The change in point of view is due to the forced realization that domestic supplies of new metals are limited and many foreign sources are at least temporarily closed. The stock piles must be cultivated. The reserves must be made more nearly permanent. Steps are being taken : (1) develop methods for recovery of scrap metals heretofore not recovered, and (2) restrict strategic metals to uses ensuring a large percentage of re-use, which in turn means substitute materials in the dissipative uses.

Jan 1, 1942

By Joseph Jensen

CURTAILMENT of oil production in California began in 1922 and 1923 when certain of the major companies completely shut down some pumping properties. Efforts of this kind were generally carried on without coordination by individual companies until 1923. From May to August of 1923, oil production in the Los Angeles Basin was curtailed because of lack of pipe-line outlets. This work was handled by a small committee of executives and engineers of some of the pipeline companies without any established. Method such as obtains at present. Not all of the major companies participated in ibis curtailment and the effort was not well organized. The problem then was principally to move the oil. The crisis passed in September of 1923 from then on the major companies each on it own initiative, shut in additional production. At Domiuguez, in 1921, Shell, Union and Associated agreed to limit drilling to a 100-ft. zone for one Near. In the summer of 1925, operators at Ingde-wood agreed to limit developments to a 1300-ft. zone during the 1925 drilling campaign. In the summer of 1927, the Ventura operators cut back their production one-third and deft it thus for 90 day. Drilling in this field has always been at a slow and conservative rate.

Jan 1, 1932

By FREDERICK C. BROWN

THE practice of fine-grinding is now being so successfully - carried on in some fields, notably in West Australia, and its advisability has been so frequently pointed out' that the matter in this paper is not put forward as being new ; its chief object being to call attention to the importance of fine-grinding in the treatment of comparatively low-grade ores. I have been engaged during the last five years in the cyanide-treatment of ores in the Ohinemuri district (North Island), New Zealand, and I consider that, in the near future, extremely fine-grinding (almost sliming) will become a very important feature of the milling-methods in this field, since it seems absolutely necessary to reduce the most of ores to a very fine state of division if a high extraction is to be obtained; and, in most cases, the extra percentage of saving will leave a good margin above the increased cost of treatment due both to the fine-grinding and to the interest on the capital spent for the grinding-machinery. The average ore of the Ohinemuri field is composed of a quartz-gangue with some calcite, carrying the gold-value in the form of an alloy of gold and silver in about equal proportions, and the silver-value in the form of mixed sulphides of silver, usually associated with a considerable amount of iron pyrites. In the upper levels, the ores are decomposed and carry large quantities of black manganese oxide and some iron oxide, but, as. depth is reached, the decomposed ore gives place to sulphides and, in some mines, rhodonite, manganese silicate, is present in fairly large quantities. The average value of the

Jan 1, 1906

By FRANK RIEBERS

IN DISCUSSING the selection of a geophysical method, much of what the writer will say is applicable to any of the various methods and to their use in prospecting, whether for oil or for other minerals. Specifically, the writer's subject is the problem, particularly pressing on the Pacific Coast, of checking the rising cost of the discovery of new fields by the proper employment of geophysical methods. Table I was prepared from statistics published by the California State Milling Bureau. The writer selected five of the largest a:ld most active companies operating in California, segregated the number of wild-

Jan 1, 1930

By T. C. Craig

During the year, there were 570 oil wells completed for a total daily initial production of 365,352 bbl. The daily oil potential of the field, effective Jan. 1, 1935, as established by the Texas Railroad Commission, was 306,102 bbl. with a daily allowable of 58,800 bbl., whereas, on Dec. 31, 1935, the potential was 587,376 bbl. with a daily allowable of 57,800 bbl. Because of the limited market demand, the allowable decreased although the potential increased. In August, the five-day test for determining the potential production of a well was replaced by a 24-hr. test. The reason for this change was that some of the oil-pur-chasing companies contended that too much oil in excess of the limited market demand was produced during the five-day tests. Dry Gas.—During July, the Texas Railroad Commission supervised the first complete and accurate field-wide test of open flows that has been made in this area. The total open flow as determined at that time was 16,426,085,000 cu. ft, There were 79 gas wells drilled in '935, with a combined open flow of 2,408,000,000 cu. ft. and 50 depleted oil wells were plugged back for gas with a total open flow of 529,800,000 cu. ft. The total new gas production for the year was, therefore, 2,937,800,000 cu. ft. The 17 natural-gas pipe lines drawing on the Panhandle supply of fuel gas withdrew a daily average of 420,497,507 cu. ft., or a total of 153,481,-590,000 cu. ft. for the year. The 44th Texas Legislature passed a statute known as House Bill No. 266, which was designed to prohibit waste and protect correlative rights by compelling the ratable production of gas. The part of the law relative to withdrawal of sweet gas became effective Aug. 1, 1935, and the part referring to withdrawal of sour gas became effective Oct. 1, 1935. Three of the major pipe line companies attacked the validity of the ratable production feature of the new law and a preliminary injunction was granted by the Federal District Court. The final hearing on the incrits of the case is scheduled for the early part of January. Natural Gasoline.—Forty of the 42 natural-gasoline extraction plants in the Panhandle operated throughout the year. One plant discontinued

Jan 1, 1936

By T. C. Craig

During the year, there were 570 oil wells completed for a total daily initial production of 365,352 bbl. The daily oil potential of the field, effective Jan. 1, 1935, as established by the Texas Railroad Commission, was 306,102 bbl. with a daily allowable of 58,800 bbl., whereas, on Dec. 31, 1935, the potential was 587,376 bbl. with a daily allowable of 57,800 bbl. Because of the limited market demand, the allowable decreased although the potential increased. In August, the five-day test for determining the potential production of a well was replaced by a 24-hr. test. The reason for this change was that some of the oil-pur-chasing companies contended that too much oil in excess of the limited market demand was produced during the five-day tests. Dry Gas.—During July, the Texas Railroad Commission supervised the first complete and accurate field-wide test of open flows that has been made in this area. The total open flow as determined at that time was 16,426,085,000 cu. ft, There were 79 gas wells drilled in '935, with a combined open flow of 2,408,000,000 cu. ft. and 50 depleted oil wells were plugged back for gas with a total open flow of 529,800,000 cu. ft. The total new gas production for the year was, therefore, 2,937,800,000 cu. ft. The 17 natural-gas pipe lines drawing on the Panhandle supply of fuel gas withdrew a daily average of 420,497,507 cu. ft., or a total of 153,481,-590,000 cu. ft. for the year. The 44th Texas Legislature passed a statute known as House Bill No. 266, which was designed to prohibit waste and protect correlative rights by compelling the ratable production of gas. The part of the law relative to withdrawal of sweet gas became effective Aug. 1, 1935, and the part referring to withdrawal of sour gas became effective Oct. 1, 1935. Three of the major pipe line companies attacked the validity of the ratable production feature of the new law and a preliminary injunction was granted by the Federal District Court. The final hearing on the incrits of the case is scheduled for the early part of January. Natural Gasoline.—Forty of the 42 natural-gasoline extraction plants in the Panhandle operated throughout the year. One plant discontinued

Jan 1, 1936

By D. R. THOMAS

GENERALLY speaking, the production of other metals in Mexico fluctuates with that of silver. The first commercial discovery of mineral was in Taxco, Guerrero, in 1552. Five years later, the patio process was introduced at Pachuca, by Bartolome de Medina. In 1884, the main line of the Mexican Central R. R. was completed and a few years later, the National railway. In 1907, the patio process, after 350 years of successful operation, was replaced by cyanidation. Soon after the completion of the railroads, smelters were built at various points and provided means of treating ores that could not be treated by any of the processes existing at that time, such as patio, lixiviation, or pan amalgamation. As a result, a number of mines were developed along the railroads and even far \ out in the mountains. In order to facilitate the shipment of this ore to the smelters, purchasing agencies were established, which for a time were very profitable; most of these agencies are now permanently closed.

Jan 1, 1921

By A. C. Fieldner

COKE and by-products have prime importance in the war program. The past year was marked by the construction of new and the rehabilitation of old by-product and beehive ovens and by the increase of production from existing plants to practically 100 per cent capacity. W. T. Brown's paper, "Plan to Improve Blast-Furnace Coke," presented at the Fuels Conference in St. Louis, Sept. 30, showed how the blending of low- and high-volatile coal improved the physical properties of coke and that improvement of the quality and uniformity of coke favored an increase of blast-furnace capacity- a vital need in the war program. Others in the industry have likewise increased production of coke or recovery of by- products by various innovations or changes in operation. Recognition of the value of pooling these developments for the benefit of the entire industry led to organization of a survey of coke- oven plants and blast furnaces by the Bureau of Mines in co-operation with the Solid Fuels Co-ordinator with a view to improving metallurgical coke production and recovery of by-products. This survey is being conducted with the help of an advisory committee consisting of representatives of the Bureau of Mines, the Solid Fuels Co-ordinator, the War Production Board, and the blast-furnace, coke-oven, and coal-mining industries.

Jan 1, 1943

By F. G. Cottrell

(New York Meeting, February, 1912.) ABOUT a year and a half ago, at the San Francisco meeting of the American Chemical Society, in connection with the excursions to local smelting-works, I had occasion to show some lantern-slides illustrating the recent commercial development of electrical methods for precipitating the suspended matter from smelter-smoke, the underlying phenomena of which were clearly brought to the attention of the technical public by Sir Oliver Lodge as long ago as 1884. In the Journal of industrial and Engineering Chemistry, August, 1911, most of these views were reproduced, together with an account of the work from its beginning up to July, 1911. To-day I wish particularly to show you some of the further developments of the work since that time; but in order to make these clear they will be prefaced by a brief abstract of the article above referred to. The removal of suspended particles, front gases, by the aid of electric discharges is by no means a new idea. As early as 1824 we' find it suggested by Hohlfeld 1 as a means of suppressing ordinary smoke, and again a quarter of a, century later by Guitard.2 These suggestions, which do not seem to have stimulated any practical study of the question, were soon entirely forgotten, and only brought to light again by Sir Oliver Lodge,3 many years after he himself had independently rediscovered the same phenomena and brought them to public attention 4 in a lecture before the Liverpool Section of the So-

Jul 1, 1912

By A. N. Crownover, H. T. Kennedy, E. P. Miesch, C. H. Bowman

The paper presents correlations of (l) molar volume of gaseous hydrocarbon mixtures with pressure, temperature, composition and properties of the C,-plus fraction; (2) shrinkage of oils during flash and differential liberation of gas, including the calculation of formation volume factor under various conditions; and (3) bubble-point pressure with temperature, composition and characteristics of C, plus. The data on which the correlations are based comprise 1,615 measurements on 900 hydrocarbon systems, including numerous systems containing nitrogen, hydrogen sul-fide and carbon dioxide. In each correlation, the number of data points covered and the accuracy is substantially greater than in previously available work. Thus, the equation yielding molar volumes of gases has an average deviation of 2.04 per cent, applied to mixtures having temperatures up to 313F and pressures up to 9,800 psis, compared to 2.37 per cent for the Benedict-Webb-Rubin equation applied to the same data, and 4.53 per cent for the method based on the law of corresponding states. he equations resented are all explicit in the dependent variable, and require no iteration on the digital cow puter. INTRODUCTION The ease and accuracy of determining the composition of hydrocarbon mixtures, compared to the difficulty of measuring their properties under reservoir conditions, makes it desirable to utilize composition as the key to physical behavior to the greatest possible extent. As a result, there are available correlations between composition, or easily measured characteristics dependent on composition, and practically every important engineering property of reservoir fluids. The task confronting us is one of finding more exact relationships between important variables rather than extending correlations to new properties. This paper describes new correlations of molar volumes of gases, formation volume factors, and bubble-point pressures with composition, temperature and where possible, pressure. Each correlation is obtained by employing a sufficiently large amount of data so the calculated properties are probably as least as accurate as the measurement on which they are based. MOLAR VOLUME OF GASES Although many equations of state have been proposed for pure gases, only a few methods are applicable to hydrocarbons at conditions comparable to those in petroleum reservoirs. Still fewer arc useful in describing the behavior of mixtures, with which the petroleum engineer is largely concerned. The correlation presented here involves procedures similar to those of Alani and Kennedy The van der Waals equation is modified to make a and b functions of temperature instead of being constants for each material.This is a cubic equation, which may have either one or three real roots. The lowest root corresponds to liquid volume, while the highest applies to gas. When the procedure was applied to 703 pressure-temperature points of 164 gases of known composition and volume, the average deviation was 12.08 per cent, and the standard deviation 8.15. The above calculations were made using the constants derived for liquids by Alani and Kennedy and the mixture equation developed by them. A closer approximation to measured molar volumes is obtained by employing different sets of constants for different areas on the pressure-temperature chart, and by changing the relationship between a,,, and b,,, for mixtures and the a, and b, for individual hydrocarbons. The various sets are shown in Table 1, and the areas for which they are recommended are plotted in Figs. 1 through 7. In these figures, the area designated by zero is in the critical region for pure materials, and the values obtained for them may be unreliable. For normal mixtures, however, the area may be added to any of the bounding areas without substantial error. The new relationships employed are

Jan 1, 1966

By T. T. Read

FOR the second time the Mineral Industry Education Division opened the sessions at the Annual Meeting by gathering at the Engineering Woman's Club, Sunday at 3 p. in., and, in spite of the informality of the hour, with a good attendance of representative men in the educational field. The chairman of the Division, Thomas T. Read, after briefly reviewing some of the more significant events of the past year, introduced H. P. Hammond, professor of civil engineering, Brooklyn Polytechnic Institute, a leading figure in the project of the Engineers' Council for Professional Development for accrediting engineering schools. Prof. Hammond made it clear that the project is not to rate engineering schools but to accredit them; not to arrange them in order of excellence, but to segregate them into two groups, those that are entitled to recognition as genuine engineering schools, and those that are not. About thirty schools in the whole country will presumably fall into the latter class; they are typified by an unnamed institution where the teacher of mathematics bears the title of Professor of Civil Engineering and the man who teaches chemistry that of Professor of Chemical Engineering, and having no engineering instruction except some elementary surveying, but still claiming in its catalogue to be an engineering college. While everyone would like to avoid the necessity of accrediting engineering colleges, it cannot be avoided, since the University of the State of New York, and several other agencies, are already doing it. If it cannot be avoided it is best that it should be done by a qualified agency set up by the national engineering societies, so that the results may command respect and general acceptance. It is for this reason, and this alone, that the accrediting committee of the E. C. P. D. has been set up. It is now ready to begin its task, and during-the coming year it will accredit the schools in two of the seven geographical districts into which the country has been divided, beginning with New England and the Mid-Atlantic States.

Jan 1, 1935

By Harrison Souder

MAGNETITE mining and milling in the Eastern States showed continuing improvement during the year. Some of the smaller mines remained idle, but the larger operations responded promptly to the improved situation in the iron and steel industry. The output of ore for 1936 was over twice that for 1935. A number of improvements were made in mine plant and equipment, and operating forces were increased and maintained at near normal. The coming year should see additional mines started up and production increased at the larger properties.

Jan 1, 1937

By William F. List, Marvin A. Schuster

Monolithic electrooptical mosaics of 2500 photo-transistor elements with internal row and surface column interconnections have been fabricated by epitaxial-planar diffsion techniques. Unique access to any elemed of the mosaic is provided through one of the fifty X and one of the fifty Y external leads. The sensor mosaic can be used for imaging applications and has a 1:1 aspect ratio, a resolution of 100 lines per in., a dynamic range in excess of lo3, a sensitivity of 0.5 per pw, element response within a 2:l range over 75 pct of the mosaic, and a minimum detectable signal of the order of 10-' w. Design considerations which ilnpose particclar fabrication yequirements are disctussed along with some of the problems peculiar to the epitaxial and planar-dijfision techniqes by which this device is fabricated. The solid-state silicon monolith has an imaging area of 0.5 by 0.5 in. and an element center -to- center spacing of 0.010 in. J monolithic solid-state electrooptical device has been developed as the photon-sensing mosaic for use in an image-converter system.' This system is the solid-state equivalent of the vidicon and can image radiation in the visible and near-infrared regions of the spectrum. The electrooptical image converter has the desirable size, weight, reliability, and low-power characteristics inherent in solid-state devices. It is read out by direct-wire means rather than by beam-scan techniques. The packaged unit is shown in Fig. 1. A selection of material for the sensor was based on considerations of both reliable fabrication techniques and material spectral response. Silicon was selected both for its response from the lower end of :he visible to the long-wavelength cut-off above 11,000A and for its well-developed epitaxial planar-diffused technology. The electrical image is composed of M x N discrete information bits with each bit emanating from one of the individual phototransistor sensors. The interconnected mosaic concept was introduced to provide a structure which is both manageable in its number of leads and compatible with conventional viewing systems which accept XY data. Interconnections along the Y direction are provided by internally diffused strips, while interconnections along the X direction are formed by vacuum-deposited metal surface bars. Unique access to any individual element of the M x N mosaic is available through one of the M and one of the N external leads. PHOTOTRANSISTOR DESIGN A phototransistor structure2 was selected for the discrete photon detectors of which the mosaic is com- posed. Basically, the mode of phototransistor operation is such that incident quanta are absorbed in the base area of the element where they generate electron-hole pairs. If the electrons are liberated within a diffusion length of the depletion region around the collector junction, they will diffuse to this depletion region and be swept across the junction where they account for a small component of the photocurrent. Similarly, the holes which are created within a diffusion length of the emitter junction will diffuse to this region where they forward bias the emitter and so induce injection of minority carriers into the base. This accounts for the substantial transistor photocurrent. This mechanism of operation implies several design and fabrication goals for the individual sensor elements: high electrooptical conversion efficiency, sufficient carrier lifetime in the base regions, and a maximum volume in which photons can be absorbed within a diffusion length from the depletion layer about the junction. Moderately high transistor gain is desirable to permit readout at low light levels; however, very high gain has a deleterious effect on mosaic dynamic range. The mosaic must also be characterized by good uniformity of element response as well as by good isolation between elements. The above set of conditions imply that junction depths must be optimized with respect to photon ab-

Jan 1, 1967

By AIME AIME

The name and address of the school are given first, followed by the length of the regular undergraduate curriculum, the degree granted, types of courses giben, and the name of the man in charge. This covers only work for the first or Bachelor degree in each case. The following abbreviations are used: B. Bachelor Cer. Ceramic. E. Engineer or Engineering Eng. Engineering or Engineer Geol. Geologist, Geological, or Geology M. Mines or Mining Met. Metallurgy or Metallurgical Mng. Mining Pet. Petroleum Ref. Refining S. Science Tech. Technology or Technical

Jan 1, 1939

By H. Rush Spedden, Arvid Thunaes

R. R. Knobler and F. E. Albertson—Following the testwork done by Thunaes and Spedden, a Sullivan deck plant was built for the Colquiri mill. This plant started to operate in April 1945 and continues in successful operation. Since May 1950 the Colquiri mill has operated with a completely revamped flowsheet at a rate of 1000 tons per day. The old Sullivan deck section was retained with this new flowsheet. The "slime plant" in Colquiri consists of one 12-cell Denver No. 18-Sp. Sub-A flotation machine, one 16-ft and one 12-ft hydroseparator, six five-deck Sullivan-frames and six shaking tables for cleaning up the Sullivan deck concentrates, as well as 12 Deister plus three Plat-O tables on which the fine sands, which are not treated on the S-decks, are concentrated. Only —325-mesh fines are treated on the Sullivan decks. The combined hydroseparator overflows are fed to the S-decks. From 1946 to 1949, i.e. with the "old" flowsheet and an average mill feed of 800 tons per day an average of 45 tons per day was treated on four Sullivan rougher frames. The two additional frames were used as cleaners. At times, up to 90 and 120 tons of slimes were treated successfully on this Sullivan deck installation. The average operating data for the S-deck section in Colquiri for the year 1949 were as follows: The tests reported in this paper indicated a tin recovery of 42 pct. The actual plant results for 1949 show a 54 pct tin recovery from the Sullivan decks. The total average quantity of tin produced from the S-deck section in 1949 was 15 tons of tin per month. This corresponds to 3 pct of the total mill recovery. The difference between the 6 pct overall recovery-increase expected after the tests in 1943 and the actual plant results given for 1949 is explained as follows. According to the tests, a total of 170 tons was expected to be routed to the Sullivan decks, but because of certain changes in the flowsheet and mill amplifications,

Jan 1, 1951