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By H. C. Hardison

The Yates pool, Pccos County, Texas, has greater potential capacities than any other field in the United States. This field is notable for the large return it yields on capital invested, for low production costs and for the orderly and conservative manner in which it was developed and continues to be operated. The proven area is 20,000 acres and there are 392 producing wells, or approximately 1 well to 50 acres. The theoretical daily potential is 5,250,000 bbl. as determined by l-hr. open-flow gages. Individual well gages vary from a few barrels to 8500 bbl. per hour, and well depths range from 1000 to 1800 ft. The greater part of the production is from a very porous limestone, and by agreement no productive well has penetrated the lime more than 225 ft. The forces driving the oil from the formation to the surface are hydrostatic head, expanding gas or a combination of the two. The degree of effectiveness of either depends upon the structural position of, and porosity encountered in, the individual wells. Approximately 95 per cent. of the wells in the field flow naturally. The pipe line outlet of the field at the present time is 100,000 bbl. per day, which is less than 2 per cent. of the daily potential. Difficulties and Principles of Probation It became evident during the first year of the development of this field that operators would have to devise a scheme to allocate pipe line runs equitably among their different properties. When the idea of proration was first inaugerated, the matter of spacing wells was given consideration. This was given up through fear of legal difficulties. Storage was also a question that was given considerable thought, and a plan was finally developed which went into effect Oct. 1, 1927. It was decided that the oil runs should be prorated according to the total potential capacity of all the wells which the several operators had in the field. The potential capacity of the wells was measured by a l-hr. open-flow gage. All runs to storage by an operator were deducted from his daily allowance.

Jan 1, 1931

By James Munroe

APPALLING as has been the loss of life in the last 51 months, there is one slight compensation : no longer will there be in the world a cripple, in the old meaning of the term. Men handicapped by wounds or disease, there will be, unfortunately, and in numbers beyond what the world has known since the wars of Napoleon; but neither they nor the industries from which they were called off to war will be "crippled" in the sense in which both would have been had mankind not learned the lesson of conservation and come to understand that the most important field for such conservation is not in the forests and' the mines but among men and women. From the beginning of the Great War, France, Great Britain, Belgium, and most of the other Allies have studied the problem of restoring the soldiers and sailors injured through war to physical and economic efficiency; and from their experiences, especially from that of Canada, the United States has learned much. Consequently, our task of preparing for the return of our disabled men has been easier and, in some ways, more comprehensive than theirs. Complex as are the details of the machinery which the United States has set in motion to take care of the men injured by wounds or disease, the plan itself is simple. Taught by European experience, the Surgeon-General of the Army and the Bureau of Medicine and Surgery of the Navy have provided, on both sides of the Atlantic, every known surgical and medical facility for restoring the injured or diseased man to a physical condition as nearly normal as possible. While in the hospital in France or England, on the transport coming to America, and in the hospital here, the disabled man is incited in every way to believe in his future efficiency, to want to be a normal worker, to desire to retake his place in that society of workers from which he went, temporarily, to do the greater work of preserving civilization. Furthermore, since purposeful occupation is now regarded as an essential form of, treatment with most men in the hospital, especially in the convalescing stage, many of these men will have been actually started on the road to earning before they are discharged from the army surgeon's care.

Jan 1, 1919

By A. R. Anderson

UNTIL recently all discussions directed at justify-ing the use of mechanical-loading equipment and conveyors have referred chiefly to tons per man and cost per ton. But there is another consideration that ? will speed the adoption of mechanical loading in mines even though tons per man on present day stand-ards were not increased nor the cost per ton decreased. With restricted immigration, improved facilities for education in our mining communities, and increased opportunities for recreation, the type of man who can or will throw 20 tons of coal per day over the side of a mine car is disappearing. Whether we will it or not provision must be made to replace muscular effort by mechanical means. Fortunately, indications are that the process will be accompanied by increased output per man and lower production cost, and though the outlook may now be a bit clouded in spots, all should profit by the change. The operator should enjoy a more stable business with more assured profit, the miners should get a better livelihood with less arduous effort and under safer and pleasanter working conditions, and the consumer should gain the assurance of a supply of coal always available at reasonable prices. That sounds like the millennium in the coal business perhaps. Of course, it is not, but there is just enough of that millennium stuff in it to encourage those of us who are working with today's problems of applying loading and conveying equipment to underground opera-tions. If we discern clearly that there can be no back-sliding, and that all will share in whatever advantages accrue, we will carry on more vigorously, and may right-fully expect to have the necessary cooperation of all the elements within the industry. As nature does not seem to have followed a definite plan in the formation of coal deposits it is not likely that any one standard method or type of equipment can be evolved for mining the coal. The method of mining that maybe most advantageously employed with load-ing machines and conveyors depends on the character of the strata overlying the coal as much as anything else.

Jan 4, 1927

By Richard McCaffery

THIS paper considers certain aspects of the acid Bessemer process, particularly in its relations to the duplex process-that combination in which the pig iron is first desiliconized and decarburized in acid Bessemer converters and then dephosphorized in basic open-hearth furnaces. The acid Bessemer process employs an acid-lined converter and produces an acid slag. The blow is usually thought to eliminate the silicon and manganese as oxides and then to burn off the carbon as carbon monoxide. On account, however, of the relatively large amount of metallic iron present in the converter, compared with the relatively small amount of the impurities it is desired to oxidize, the first reaction in the converter probably is the formation of iron oxide, which dissolves in the bath and acts as an oxygen carrier for the silicon and carbon. As soon as iron oxide is dissolved throughout the bath, the oxidation of silicon commences; but in the early stages of the blow the mass law would indicate that iron oxide must form first, and this oxide probably increases up to some saturation point. The molten metal in the converter from the early stages of the blow right through to its completion remains basic, while the slag produced is siliceous. This fact is shown by the corrosion of the acid bottom and the tuyeres, which is greatest at the tuyere orifice where oxidation is most active and where there is the most iron oxide. Why does this acid bottom corrode? Because it is attacked by a base. The thought, therefore, suggests itself, why not make the bottoms of basic or neutral material?1 As the converter slag is acid, those parts of the converter coming in contact with the slag should be acid; but those parts of the converter that are in contact with the molten metal saturated with metallic oxides should be basic or neutral. Bessemer operators have for some time tacitly admitted this condition, for the blast pressures have steadily increased with the object of keeping the metal in suspension, and so preventing bottom corrosion; if the molten metal were not basic, it would not attack an acid bottom. In addition, the tuyeres are bunched together at the middle of the bottom and a clear space is left around the outside of the bottom; if tuyeres are placed too near the side walls the

Jan 8, 1920

By Daniel M. Bass, Paul B. Crawford

Laboratory investigations have been made to study the effect of variations in fluid characteristics, gas saturation, water saturation, and water injection rate on oil recovery by water flooding. Three synthetic gas-saturated crude oils having bubble points of 860, 1,540 and 1,885 psi were used as reservoir fluids. Repeated tests were made in which a and pack, saturated with water and synthetic oil, was produced by solution gas drive followed by water flooding at various pressure levels. Oil recovery by solution gas drive and subsequent water injection is shown to vary with the pressure and rate at which the water flood is conducted. The pressure at which optimum flooding conditions exist is shown to be a functiotl of the physical characteristics of the reservoir fluid. For the systems studied, increases in oil recoveries of near 10 per cent were obtained by flooding at the most desirable conditions. Va- riations in initial water saturations gave results similar to those in the literature. INTRODUCTION Most of the waterflooding studies investigating means of improving present exploitation processes have been conducted at low pressures with little effort to simulate reservoir conditions. Holmgren and Morse' performed a waterflooding study at 300 to 500 psi wherein the gas saturation was created by injecting gas, letting dissolved gas evolve from the oil, and then flushing the core with "live" oil until the desired gas saturation was obtained. Their results show increasing oil recoveries with increasing gas saturations. Data presented by Guerrero' and Kennedy, et al, indicate that in some instances water flooding at approximately 500 psi below the original bubble point results in a lower residual oil saturation than is obtained when water flooding above the bubble point. In their work gas saturations were created by primary depletion. By correcting low pressure flooding data for fluid shrinkage, Dyes found that a maximum oil recovery may be obtained by flooding with initial gas saturations of from 7 to 12 per cent. The purpose of this work was to determine the variations in oil recovery caused by initiating a waterflooding program at various stages of primary depletion of a core. This is a part of a more comprehensive study of obtaining criteria for determining when to initiate a pressure maintenance program and what fluids to in-ject. EQUIPMENT A schematic diagram of the apparatus is shown in Fig. 1. Fluid transfer was accomplished with metering pumps. Pressure control was ob-

Jan 1, 1957

By R. P. O’Shea

AS part of a program to investigate phase relationships in ternary systems containing semiconducting elements and compounds, an X-ray survey of alloys in the system Pb-Te-Bi was carried out which revealed that the pair PbTe-Bi probably formed a quasibinary system. This portion of the ternary was examined fully by thermal analysis, X-ray, and microscopic procedures. More than twenty-five alloys were made by melting together the proper combinations of the elements in quartz tubes at a temperature of 1000o C. The compositions which were high in PbTe content were prepared in evacuated, sealed, quartz tubes, allowed to freeze in vacuum, and then transferred to Crucibles for thermal analysis. The bismuth-rich alloys were made directly in the crucibles under a protective gas cover. The starting elements were obtained from the American Smelting and Refining Co. and had a purity greater than 99.99 pct. Cooling curves were made with about 50 g of alloy in graphite crucibles which were placed in a covered quartz container in which a protective atmosphere of helium or nitrogen was maintained. The thermocouple protection tube was made of mul-lite and served as a stirring rod when connected to a reciprocating stirring motor. Temperatures were

Jan 1, 1962

By N. W. Sager, H. W. Mossman

The arrangement and general dimensions of the reverberatory furnaces and waste-heat boilers for the Nos. 2 and 3 smelting units at the McGill plant of the Nevada Consolidated Copper Corporation are shown in Fig. 1. Each of the two reverberatory furnaces has its own set of waste-heat boilers, and before February, 1932, each furnace, when it was in operation, delivered waste-heat gases to its own boilers only. In January, 1933, the idea was suggested of using some of the waste-heat boilers as economizers to operate in conjunction with the waste-heat boilers that were generating steam. The execution of this idea gave rise to the gas-flow scheme depicted in Fig. 1, the advantages of which were obvious, particularly so in view of the fact that for some months prior to the adoption of this scheme the smelting had been confined to No. 2 furnace, with No. 3 furnace and its boilers idle. The waste-heat gases from No. 2 furnace pass through the boilers serving this furnace as steam-generating units, thence through the original exit duct to a point where a bulkhead diverts the gases in a reverse direction through two of the boilers of No. 3 furnace. After the gases have traversed these two boilers, another bulkhead placed in the duct between No. 3 furnace and its boilers causes them to traverse still one more boiler, from which the gas path leads to the stack. In this scheme the last three boilers traversed by the gases, i.e., the boilers behind No. 3 furnace, function as economizers and preheat the feed water for the two steam-generating units directly serving No. 2 furnace. This discussion will give consideration to the results obtained in waste-heat recovery by the scheme shown in Fig. 1, and, further, will compare these results with those obtained before the boilers of No. 3 furnace were set up to act as economizers, but before going into the detail of heat generation, distribution and recovery, will present some additional details of the equipment. All boilers in this waste-heat plant are of the Stirling type. The two behind No. 2 furnace, acting as steam-generating units, of class 13, are 40 tubes wide and rated at 1112 boiler hp., while the three boilers behind No. 3 furnace, acting as economizers, are also of class 13, but 28 tubes

Jan 1, 1934

GEORGE F. COMSTOCK (author's reply to discussion*).-Mr. Thum's description of the effects of butt welding and spot welding on the micro-structure of steel are interesting and timely. The speed with which the changes noted by Mr. Thum must take place is indeed remarkable, but the writer has noted a similar very rapid diffusion of carbide in annealing a t a rather high temperature certain samples of soft sheet steel containing massive cementite segregated on a small scale. The massive cementite in such steel can be dissolved and distributed very quickly if the proper temperature is attained. Mr. Thum's explanation of the structure he found in the spot welds seems entirely reasonable, but the mystery of the decarburized material in the butt weld is one that might well be the subject of further research. The possibility of decarburization by air ,might perhaps be worthy of a little more consideration than he gives it, for the oxides formed would be gaseous on account of the presence of carbon, and hence not visible in the microscope, and the effect of the pressure might be to squeeze the carbon oxides, which would normally form blow-holes, out of the metal or possibly into such small volumes as not to be noticed The removal of carbon by liquation and squeezing into the fin would be an effect similar to the "bleeding" of a steel ingot that is rolled while the center is still liquid, giving a soft low-carbon interior in the finished section while the segregate was removed in cropping the pipe. This effect in Mr. Thum's butt welds could, however, only be obtained if the weld was heated to near the melting point of the steel, and if the carbon was considerably segregated in the bars at the start, for the first effect of the high temperature would be to promote diffusion rather than the contrary segregation and Equation. It is gratifying to learn from Dr. Ruder's remarks that his researches have resulted in no disagreement with the few points brought out by the writer's experiments. In addition to the three forms in which nitrogen may occur in iron that he mentions, it would seem that a fourth form is often found; This is apparently a eutectoid, like pearlite, and sometimes almost as coarse as the massive cementite seen in soft steel sheets that have been annealed for a long time. One of the things needed in the metallographic study of steel is an etching reagent that will distinguish definitely between nitride in this form and the more common pearlite or cementite.

Jan 6, 1919

By Woolsey Johnson

THE object of this paper is to, describe the several necessary characteristics of the zinc-retorting charge and to show how by certain improved methods; the large excess of coal, over that theoretically required, can be reduced, thereby effecting an increase in the smelting capacity of a retort plant as well as other economies. In the Southwestern zinc works a charge of roasted zinc ore with a side mixture of carbonates and silicates, analyzing on the average 50 per cent. Zn, is mixed with 55 or more per cent. of its weight of a mixture of coal and coke analyzing 60 to 70 per cent. fixed carbon. . The ore is of varying fineness and the coal and coke are usually crushed in a semi-moist condition through a 3/8 -in. screen. With ores of a slaggy nature, this coal proportion is increased, sometimes to as much as 100 per cent. of, the weight of the ore. With carbonate ores, or where anthracite screenings with higher carbon content are cheap enough, the percentage of reducing agent is cut to 45 per cent. or even somewhat lower. The average charge per retort for a monthly run of a plant on ore, as distinguished from retorts on blue-powder, ladle-skimmings and other between-products, runs from 60 to 66 lb., with a mean of 63 lb. for the Southwest with standard retorts of 8 ½ -in. inside diameter and 50 in. long inside, using roasted sulphide ores. Conditions will change these figures, but 40 lb. of ore per cubic foot of retort space is, I believe, an average in the better-operated plants. Since the rise in. the price of spelter, the tendency has been to overcharge. To remove the slag that is formed when retorts are overcharged, extra men are put on to "gum-chisel" the retorts to prevent "set" furnaces and "butchered, retorts." Taking the above conditions as premises, we find that from four to six times the amount of coal necessary for the reduction is used, as is evidenced by the fact that the residues analyze as high as 35 per cent, fixed carbon. There are good reasons why this excess of fixed carbon must be used and perhaps these can be best explained by a description of the metallurgical requisites of a zinc charge. We may enumerate these as follows: 1. High reducing power, especially at the end f the shift, to reduce any carbon dioxide to monoxide and bring about a good condensation

Jan 2, 1918

By William Kent

In a paper by Mr. Frank Firmstone, published in vol. iv, of the Transactions of the Institute, on " Comparison of Results from Open-topped and Closed-topped Furnaces," the regularity of the average grade of pig iron procluced by the furnace under different conditions is expressed by means of a curve or diagram. The object of this note is to show that the graphic method, or that of representing variations by plotted curves or diagrams, is capable of a much more extended application to blast-furnace records, making a valuable auxiliary to the " furnace hook," and that by it the practical metallurgist may obtain at a glance information concerning the variations of the furnace during long periods, which could be found in the furnace book only after a tedious search. Plate XII is a graphic record of an anthracite blast furnace for one month. The table on page 554 gives the figures obtained from the furnace book, together with a record of temperature of the atmosphere, barometric pressure, and moisture in the air, which was obtained from a meteorological observatory not far from the furnace. In the records of a furnace, two of the variable qualities are final results, viz., the quantity of pig iron produced, and its grade; all the other variables are antecedent causes which produce the final results. Of these variable callses which contribute to the quantity of product and its grade, some are partially under the control of the furnace manager, others depend upon the state of the atmosphere, and still others are accidental. Of the first class are the character of the materials charged, and their relative proportions, their mechanical conditions, as wetor dry, large or small pieces, etc., the revolutions of the engine, the heat and pressure of blast, and the distribution of the charge. Of the second class are the number of pounds of air blown into the furnace for each stroke of the engine, the amount of moisture in the air, and the condition of the chimney draughts. These vary largely with the season of the year. Of the third class is the leaking of a tuyere or a temporary stoppage. To keep a record of this kind for a whole year, it is only necessary to procure a sheet of common profile or cross section paper, about 38 inches long and 8 or 10 inches wide, with cross lines ruled about 0.1 of an inch apart. The vertical lines, or those in direction of the

Jan 1, 1879

By P. Campbell, E. M. Gardy, L. Hachkowski

Introduction The efficient process control of a uranium mill and its associated mining operation requires a nearly continuous knowledge of the uranium concentration in the ore. Generally, the approach is to use laboratory assays of grab samples from the mill feed belt. In some cases, elaborate and expensive systems have been used to ensure random sampling, but even with these systems, mass-balance discrepancies still exist. There is a requirement for an on-line instrument that can give a prompt, accurate analysis of a large portion of the feed stock. The authors have recently evaluated a laboratory system that achieves these goals using neutron activation and delayed neutron counting. The development of the on-line uranium ore analyzer is a consequence of previous work done at the Whiteshell Nuclear Research Establishment (WNRE) (Campbell et al., 1978 and 1981), and is based on the emission of delayed neutrons after the neutron irradiation of fissionable materials. The mechanism of delayed neutron emission has been described (Keepin, 1965), but briefly is as follows. The fission fragments resulting from irradiation are in an excited state. Certain of these delayed fission products, precursors, decay to a more stable state by the emission of a delayed neutron. The delayed neutrons can be divided into six groups with effective half-lives ranging from 0.2-55 sec. It is important to note that more than 50% of the delayed neutrons are emitted within the first 6 sec after irradiation; this has an influence on the design of the analysis instrument. Measurement Cycle The measurement cycle involves a neutron irradiation, a delay time, and a counting period. The laboratory demonstration model of the ore analyzer comprises a californium-252 neutron source, a source chamber, a pneumatic transfer facility, and a neutron irradiation and counting module [(Fig. 1)]. The ore sample is placed in the irradiation chamber. The neutron source is transferred to the center of the chamber for a 5-sec irradiation while the helium-3 thermal neutron detectors are switched off. As the source returns to the storage chamber, the detectors are switched on and the delayed neutrons counted. The total assay cycle is 16 sec. The current instrument design calls for the ore to be cut from the main belt every 16 sec by a mechanical arm and dropped into the analyzer directly, or via another belt. The cycle starts when there is a sufficient mass of ore in the irradiation chamber to depress a switch and stops when the delayed neutron count is finished. The ore is then dropped through the bottom of the analyzer chamber and returned to the main belt. The counts from each cycle are accumulated and the data reduced to give the desired information.

Jan 1, 1985

By Wm. C. Phelps, R. E. Grace

b R.c c)nduciivity of slags and glasses is of particular interest when viewed as an activated ionic flow process. The ionic conductivity, for example, has been found to obey the Easch-

Jan 1, 1958

By I. Fatt

Networks of resistors are used as analog computers to obtain relative permeability and resistivity index curves for networks of tubes. These curves have all of the characteristics of those obtained on porous media and, therefore demonstrate the validity of the network of tubes model. INTRODUCTION In paper I' of this series the network model was shown to give information on the structure of porous media that could not be obtained from the bundle of tubes model. The agreement between the capillary pressure characteristics of a network of tubes and those of typical porous media does not prove the validity of the network made. The bundle of tubes model, although it gives less information, also shows this agreement. In this paper the flow properties of a network of tubes are shown to be in agreement with flow properties of porous media. The flow properties of the bundle of tubes model are not in adequate agreement with those of porous media. The dynamic properties of porous media, such as fluid permeability and electrical conductivity, have been found experimentally to be more sensitive functions of structure and pore size distribution than are the static properties such as porosity and capillary pressure characteristics. The network model can, therefore, be best tested by comparing the dynamic properties of a network of tubes with the observed properties of porous media. All static and dynamic properties of a completely valid model must agree with the observed properties. The most commonly measured sensitive dynamic properties are the relative fluid permeability and the relative electrical resistivity. Experimental measurements of these dynamic properties on sandstone, sintered glass, sintered alumina, and soil are reported in the petroleum and soil science literature. These properties were chosen, therefore, for the test of the network model. In the network model, relative permeability is the permeability of the network when some of the tubes are not conducting fluid, relative to the permeability when all tubes are conducting fluid. Similarly, the relative resistivity is the electrical resistivity of the network of tubes when some of the tubes are filled with a nonconductor. relative to the resistivity when all tubes are filled with the electrical conducting fluid. Single Size Tube Network The simplest porous medium is one in which all pores are of the same size. Such media can be approached by packing beds or columns of uniform size particles of sand, glass, or metal. The model of such medium in this study is a network of single size tubes. The network form, the ß factor, is usually not known for real porous media. If the validity of the network model can be established, then the study of the flow properties

Jan 1, 1957

By E. S. Machlin

THE function of this paper is to present certain results based on the fact that the strain energy arising from the solution of out-of-size solute atoms into the solid matrix is free energy and not internal energy, and that this strain energy is almost wholly shear strain energy as Zener1 pointed out. One natural consequence of this fact is an expression for the excess entropy of mixing due to the strain energy. Also, a derivation of the integral molar free energy of mixing partitioned to strain energy will be made using the model of Lawson2 and thermodynamics. This derivation has the advantage of showing in a simple way the assumptions involved in Lawson's treatment. The excess entropy of mixing partitioned to strain energy can be derived in two ways. The first way makes use of the fact that the strain energy is almost wholly in the form of shear strain energy. In this case, as Zener1 pointed out, the change in entropy due to the addition of shear strain energy is to a first approximation given by ?S/?? p,T = - ?lnµ/?T p,? Hence, the excess entropy of mixing partitioned to strain energy will be given by Sx ? = ?S/?? p,T Gx ? = - ?lnµ/?T p,? Gx ? where, Gx ? is the relative integral molar free en- ergy partitioned to strain energy; S is the entropy; is the shear strain energy; µ is the shear modulus; T is the absolute temperature; p is the pressure; and ? is the shear strain. Zener,1 as well as others, has pointed out that the shear strain energy stored in a compressible isotropic solid due to the insertion of an off-size incompres-sible sphere into a spherical hole in the solid, is approximately given by 2/3 µ/O (O°I - O)2 where a is the volume of spherical hole and no , is the volume of sphere. If we now consider the introduction of one mol of such spheres into an infinite volume of solid, then the relative partial molar free energy excess due to strain energy alone is GM ? = 2/3 µ/v (v ° 1 - v)2 where v is the molar volume of solvent and v°1, is the molar volume of pure solute type 1. Let us consider that these spheres are the two types of atoms in a binary solution, then there will be a similar relation for solute 2. The total relative integral molar free energy excess due to strain is then, to the approximations stated above GM ? = GM ? x1 + GM2 ? x2 = 2/3 µ/v [(v ° 1 - v)2 x1 + (v ° 1 - v)2 x2]. Lawson's relation for the strain energy can be de-

Jan 1, 1955

By John M. Dealy, Robert D. Pehlke

This note presents a summary of the available literature on activity coefficients at infinite dilution in binary metallic solutions, Table I. These data should prove useful in not only examining the therm-odynamic properties of binary metallic solutions, but also in predicting the activity of a component in a complex alloy. The relationship proposed by wagner1 for expressing the activity coefficient in dilute solution is of the form:

Jan 1, 1963

Discussion of the paper of G. P. Hulst, presented at the Salt Lake meeting, August, 1914, and printed in Bulletin No. 92, August, 1914, pp. 1865 to 1871. L. S. AUSTIN, Salt Lake City, Utah.-One question that I would like to ask is in regard to the sampling kettle which stands beside the softening furnace. How is the sample taken or melted? G. P. HULST.-The sampling kettles in question are of 45 tons capacity and are fired with coal. The lead bullion comes in on a high line in car-load lots of 30 to 40 tons. The entire lot is trucked from car, weighed over scales and thrown into the sampling kettle, which has been previously cleaned. The kettle is fired and the bullion melted, then heated up until no frozen bullion' remains in the .bottom or adheres to the sides of the kettle. The kettle is scraped clean, sides and bottom, and the wet dross is skimmed Doff clean into molds. The kettle is stirred thoroughly during the period in which 24 to 30 samples of approximately ½ assay ton are taken. These samples are taken in a long-hand loci iron mold, providing for taking six to eight "gumdrops." The mold is inserted and heated to the same temperature as the molten metal, and gumdrops are clipped out and cooled in the mold by dipping 'the bottom of. the mold into Water. The samples should be free from fins. The gumdrops represent the contents of the kettle, and in assaying, they should not be clipped, but weighed up and the result computed. The dross bars are weighed and sawed according to old hammer and punch sample template. The sawdust represents a sample of the dross. In eases of high gold in the bullion there is a slight correction in the assay. This method of sampling was developed at the Omaha plant of the American Smelting & Refining Co., W. T.. Page, Manager, in 1903 or 1904, for adjusting differences in checking smelter sampling. L. S. AUSTIN.-The base bullion which you treat is very clean. It has been remelted, and skimmed before shipment. How rapidly can you get it through the softening furnace, and how does it compare with ordinary base bullion? G. P. HULST.-Twenty-four hours is the softening limit on these charges. In other words, it is charged into the furnace, heated up, and the first and second skimmings are taken off, and it goes into the kettle the next day; that is, 24 hr. elapse from the time the bullion is charged to the time it is in the kettle. L. S. AUSTIN.-It seems to be a long time to hold such a pure bullion. I suppose, though, it comes around conveniently so that you have a time for all the other operations of refining. Isn't that the case? MR. HULST.-Every refinery is based on those principles.

Jan 11, 1914

By Walter Bonsack

THE CHAIRMAN.-This is the third and last session of the Institute of Metals Division's Symposium on Secondary Metals, and certainly the best of those that I have attended in the last few years. I would say that the increase in interest in secondary metals is quite noticeable by the steadily increasing attendance at these meetings. We have heard about the necessity of utilizing salvaged materials, but we still speak about them as low-grade, or down-graded materials. We still have the wrong perspective. We must willingly admit that these materials are valuable; we cannot go on using the choicest primary metals as morsels for our economic diet in a war of such unbelievable dimensions. This brings up the question-why are we so selective. The answer certainly is not that we know nothing else will do, but rather that we do not know what else will do. To be honest, we should admit our lack of knowledge concerning our complex alloys. Compared to the organic chemists, we metallurgists are very conservative, and the sooner we realize this and start to overcome it the better, because if we do not eliminate this difference, many customers of the metals business will go over to the plastics. If we take for example the development of aluminum alloys, you will see what I mean. From the binary aluminum alloys of 1920, we have progressed to ternary and quarternary alloys in the 1930's. We are only now beginning to use more complex alloys as we are forced to learn more about the effect of various elements on existing alloys. The effects of these elements should be studied now. They can be studied by two methods of approach. The usual method is to start from the base alloy and add various elements one by one in increasing amounts and study the resultant changes in properties. This is a tedious, long way. The other method which the smelters frequently use is to take the off-grade heats and study their characteristics. While the producer of primary alloys often has difficulties in alloying certain elements with the alloy under investigation, the smelter often finds them well alloyed in his raw materials and has no difficulties at all. Elements such as lead are difficult to alloy with aluminum and they tend to segregate severely. However, the amount which will remain alloyed in the metal is usually found in some "secondary" aluminum alloys. If one considers such concentration as the saturation, then by dilution with the same type of alloy, but free of such element, one can produce numerous intermediary alloys for investigation. In this fashion one is fairly certain to get uniformly spaced concentrations of the element under investigation. Similar cases probably exist with other metals. Nevertheless, the amount of work necessary to study all possible combinations is still tremendous. Necessity forces us now to utilize alloys which contain more elements than we are accustomed to. It is, therefore, necessary to study carefully the more complicated alloys. In secondary aluminum we are working and using the alloys which contain as many as 6 to 10 elements and we have learned over a period of several decades to balance

Jan 1, 1943

By C. E. Sims

In some experimental work conducted several years ago, it was noted that sulphur seemed to have a distinct influence on grain size of carbon steels. 111 order to check this observation, a series of S..A.E. 1040 steels was made with the normal composition held as nearly constant as possible. The steels were made with three sulphur levels, which were 0.012, 0.024 and 0.038 per cent sulphur, respectively. For each of the sulphur levels, steels were made with only silicon deoxidization and with aluminum additions of 0.1015, 0.025, 0.050 and 0.10 per cent. The melting medium was an acid-lined high-frequency induction furnace. These steels were forged and rolled and differentiall!. quenched from temperaturcs in the range of 1500O to 1800°F. After this, the A.S.T.M. grain size was determined and plotted as in Fig. I. It will be noted, first of all, that the aluminum-free steels had filler grain size with higher sulphur when heated to 1500, but that this condition was reversed at 1700°. When aluminum was added to produce fine grain size, the steels in the lowest sulphur level were fine-grained only to 1600°. and then only with an addition of one pound of aluminum per ton. The medium sulphur steels werc fine-grained to 1600' with a wider range of aluminum addition. The steels in the highest sulphur level were fine-grained at 1600° over a still wider range of aluminum additions and fine- grained at 1700° with an addition of one pound per ton. Fig. 2 shows curves of the grain-coarsening temperature for these steels and illustrates how sulphur and aluminum combine to give greater inhibition to grain growth than aluminum alone. Only the highest sulphur steels have a grain-coarsening temperaturc above 1700°.. At 1650°, the low sulphur steel is fine-grained only at its peak, while the highest sulphur steel is fine-grained over a wide range. In these tests, one pound of aluminum per ton gave the best results; this is equivalent to about 1 1/2 lb. per ton for commercial condition. IllcQuaid-Ehn tests made on these steels showed the same trend but to a lesser degree. The tests were repeated on a series of S.A.E:. 1015 steels with sulphur levels of 0.02 and 0.03j per cent. Aluminum additions were made in the range from 0.025 to 0.15 per cent. These steels were forged and rolled, normalized at 2000°F. to put them all in the same starting condition, then reheated to various temperatures from 1600" to 1800" and cooled at rates that would allow ferrite precipitation in the austenitic grain boundaries. The results of these tests arc shown in Fig. 3. It will be noted that. up to the temperature of 1650°, there is very little difference in the grain size obtained from the two levels of sulphur. .At temperatures of 1700° and 1750°, however, the lower sulphur steel was fine-grained only with an aluminum addition of 1 1/2 lb, per ton;

Jan 1, 1945

By A. F. Crawley

The densities of some liquid Pb-Sb alloys up to 11 wt pct Sb and Pb-Sb-& alloys up to 10 pct Sb/10 pct Sh have been determined by a pycnometric technique over a temperature range of about 130°C above their melting points. The data given are accurate within 0.05 pct. Density is shown to vary linearly with temperature , and equations relating these quantities have been formulated. Molar volumes calculated from the density data indicate that volumetric deviations from ideal mixing are undetectable within the limits of experimental error. A continuing research program into some fundamental physical properties of liquid metals is being pursued at the Mines Branch, Department of Energy, Mines and Resources, Ottawa, Canada. This work has received support from the Canadian Zinc and Lead Research Committee in cooperation with the International Lead and Zinc Research Organization. This paper, which reports some density data for Pb-Sb and Pb-Sb-Sn alloys, follows previous work from this laboratory on lead, tin, and Pb-Sn alloys.' Of previous data from others, Greenaway2 and Sato and Munakata3 have reported results on Pb-Sb alloys. No previous work has been published on the ternary Pb-Sb-Sn alloys, reported here. EXPERIMENTAL METHOD Densities were measured by a pycnometric technique which has been described in detail and appraised for accuracy in earlier Mines Branch reports.475 Fig. 1 shows the densitometer with the pycnometer in position for a run. The pycnometer is also shown in some detail. The pycnometer of dense, high-purity graphite, about 14 cu cm in volume, was carefully machined to a uniform, smooth finish. The height was measured by a depth micrometer and the diameter by fitting precision gage blocks between steel balls.' In each case several readings were taken, and the final results were considered accurate within 0.01 pct. The resulting volumetric uncertainty together with small inaccuracies in the coefficients of linear expansion of graphite lead to a maximum systematic uncertainty in the method of ±0.03 pct. As shown in Fig. 1, the pycnometer lid is a threaded cap. Thus, the charge, a cylinder of the alloy, can easily be inserted and the solidified metal can readily be removed after a run. The dimensions of the cylindrical charge are chosen to ensure that, once molten, the metal will not only fill the pycnometer completely but will discharge an excess into the excess-metal float chamber. AS the temperature is increased above the melting point, the volume of metal in the excess chamber increases until the system has equilibrated at the desired temperature. At this point, the excess chamber is moved to one side by twisting the shaft F, leaving a fixed volume of liquid metal in the pycnometer. This volume of fluid is readily calculated using measured coefficients of linear expansion of the graphite which expands anisotropically. The associated weight of fluid is determined as the weight of the solidified metal removed after the furnace has cooled down. Alloys were prepared from 99.997 pct Pb, 99.999 pct Sn, and 99.999 pct Sb, being melted by an electric furnace in a graphite crucible and poured into graphite molds. Several density specimens of the same nominal size were machined from each ingot, and, by comparing specimen weights, relative differences in specimen composition resulting from segregation in the ingots could be detected. In this way, segregation was found to have occurred in Pb-Sb alloys at compositions beyond the eutectic (11.2 pct Sb) and this

Jan 1, 1969

By H. F. Yancey, M. R. Geer, C. L. Allyn, R. H. Eckhouse

Four coals were treated in the Humphreys spiral concentrator, and the products were examined by float-and-sink and screen-sizing tests to determine fundamental performance characteristics. The efficiency of the separation between coal and impurity was shown to be influenced greatly by particle size. FOUR coals exhibiting different washability characteristics were washed in the Humphreys spiral concentrator and the products examined by float-and-sink and screen-sizing tests to determine the mechanics of the separation between coal and impurity. With one coal, each 1/2-in. increment of the full width of the stream in the spiral was examined separately to determine where each size and specific-gravity fraction of the feed was stratified. The basic performance characteristics of the spiral were found to be the same for all of these coals. The coarsest fraction of heavy impurity stratified so far out in the stream that it could not be removed through the refuse ports and thus either entered a middling product or contaminated the washed coal in the case of a two-product separation. Impurity particles finer than about 100-mesh also were carried out in the main body of the stream and therefore were not removed in the refuse product. Little loss of clean coal in the refuse occurred in sizes coarser than 28-mesh or finer than 100-mesh, but considerable coal of intermediate size stratified in the stream that was drawn off through the refuse ports. Because of this modifying influence of particle size, the spiral is unable to make an efficient two-product separation between coal and impurity without some retreatment. Recirculation of a middling product through the same spiral as a means of obtaining more efficient operation was not attempted in this investigation. The size and specific-gravity composition of the middling product are, however, such as to render it amenable to simple hydraulic classification for recovery of coal. Retreatment of a middling product would improve the efficiency of the spiral, but even when making a substantial amount of middling, considerable clean coal enters the refuse product. Consequently, retreatment of a combined refuse-middling product would appear to offer greater promise for providing maximum efficiency. Because of the sizing characteristics of the spiral, a classified feed can be treated with higher efficiency than is possible on a natural raw coal. For this reason, semiclassified feeds, such as silt-bank or classifier-underflow materials, can doubtless be treated with higher efficiencies than those shown for raw coals in this report. Performance is, of course, only one of many factors that enter into the choice of cleaning equipment. The fact that the one company now using the spiral for cleaning coal has built a second spiral plant is ample evidence that the inherently low efficiency of this unit may be overshadowed by the low operating costs afforded by its extreme simplicity. Introduction A number of factors enter into the selection of coal-cleaning equipment, and most of them bear directly on the final cost of prepared coal. One of these factors is performance of the cleaning unit in terms of the efficiency of the separation it effects between clean coal and refuse. The importance of performance in the selection of a coal-cleaning unit varies with the difficulty of the cleaning problem. Obviously, if the character of the coal is such that only certain types of cleaning units are capable of yielding a clean product meeting market requirements, performance is of prime importance. If, on the other hand, the cleaning problem is so simple that any type of cleaner will provide coal of suitable quality, performance is important only insofar as it affects costs by determining the amount of salable coal lost in the washery refuse. With the objective of providing the coal industry with information that is helpful in the selection of

Jan 1, 1951