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By Keith Leonard Sutherland

THIS paper is a study of the differential flotation of the sulphide minerals in the presence of salts of silver, lead and zinc. In practice, accidental activation due to these salts is more important than their use as reagents to replace copper sulphate. The general method of investigation has been based upon contact tests, the temperature of 35°C. being chosen in conformity with earlier work. Potassium ethyl xanthate and potassium amyl xanthate were selected as collectors and pure sulphide minerals were used. The experimental procedure has been outlined in earlier papers and all solutions were kept carbonate -free.1,4 Contact, or spreading of an air bubble, at a mineral surface indicates the presence of an adsorbed collector film. PURITY OF REAGENTS The xanthates were purified in the usual manner.1 Neither the cyanide nor the sodium hydroxide solutions contained sufficient carbonate to give a precipitate with barium chloride solution. The silver sulphate was prepared from pure silver nitrate by evaporation with concentrated sulphuric acid until there was no evidence of brown fumes. This solution was diluted and the difficultly soluble sulphate washed with water so that unchanged nitrate was dissolved. The resultant crystalline powder was pure white. The lead and zinc salts were prepared by dissolving especially pure lead and zinc in C.P. nitric and sulphuric acid solution and the crystals drained. The standard solutions were checked by titration. It was felt desirable to use the sulphate radical wherever possible, but since lead sulphate was insufficiently soluble for the purpose of the experiments, it was necessary to use some other lead salt. A.R. copper sulphate was used without further purification. RESULTS The results are presented in the accompanying figures; the areas of noncontact (nonflotation) are shaded in Figs. 8, 9, 10 and 11; in the remainder they lie to the right of the curve. Zinc Sulphate The curves in Fig. I are to be compared with those for Fig. 2, for which zinc sulphate is absent. This comparison shows that the influence of the zinc ion is usually small. Its influence is more marked, however, for chalcopyrite in the absence of cyanide. The influence of zinc sulphate is also marked for copper-activated sphalerite, for which tests were made only in the absence of cyanide. The results are of importance in the separation of pyrite from copper-activated sphalerite when, zinc sulphate is added in the lead flotation section (p. 204 of ref. I). Sphalerite does not adsorb the collector (i.e., become floatable) under the conditions chosen.

Jan 1, 1942

By W. R. Ingalls

The manufacture of zinc oxide directly from the ore is one of the most important contributions that America has made to the metallurgy of zinc. Heretofore, this has been done chiefly for the production of zinc and zinc-lead pigments, and the method has been known as the Wetherill process. While that term may properly be applied to the process for pigment manufacture, it must be recognized that the principles of the process are of far wider application; and that there is going to be wider application in the immediate future is more than an expectation. I have in mind the use of the process as a method of igneous concentration. Igneous concentration is broader in its scope than the Wetherill process, for it may be done in the blast smelting furnace, or in the re-verberatory, or by other means. Igneous concentration is a rather clumsy term, and I prefer to introduce the new generic expression of "zinc burning," which is convenient, readily understood, and precise, for in all cases the zinc oxide is reduced to metallic form, is volatilized and is then burned to zinc oxide, the latter happening, however, after the zinc has been separated from the residue of the ore. As previously indicated, zinc burning may be done either in blast or reverberatory smelting, the gangue of the ore being scorified and drawn off as slag, while other metallic minerals are reduced to matte or metal. Such processes have heretofore been practised on fairly large scales. Thus, F. L. Bartlett smelted zinc ores at Con City, Colo., in specially designed blast furnaces, wherein the smelting column was only about 18 in. high. Such a limitation was necessary in order to prevent zinky accretions in the shaft of the furnace, which in course of time would have interfered with its operation. In running the Bartlett furnaces it was easy to bar them off, indeed, to poke right down into the smelting zone, and keep things going freely. Some iron blast furnaces in Virginia and the spiegeleisen furnaces of the New Jersey Zinc Co. afford other examples of zinc burning in blast-furnace smelting, although in their cases the happening is incidental rather than a primary purpose. Just as zinc may be burned off in a blast furnace, so also may it be done in a reverberatory. Indeed, there is less trouble, in some respects, in a reverberatory, for therewith there is no shaft in which accretions may

Jan 1, 1918

By W. B. Humes

The use of high vacuum on a large industrial scale in the ferrosilicon process for the production of magnesium marks the coming of age of an important new metallurgical technique. The economical production of reactive metals, such as magnesium, which combine with all the well-known furnace atmospheres, has until recently been successfully carried out only by electrolytic methods. It is now apparent that, through the use of high vacuum, the distillation or sublimation of many metals can be done industrially at much lower temperatures, and hence in much simpler equipment, than heretofore has been thought possible. At the beginning of the present emergency, when the ferrosilicon process of producing magnesium was brought to the fore, little was generally known about vacuum engineering, practices, and techniques. In a comparatively short time, the available equipment has been adapted, new equipment designed and built, and a fund of know-how evolved to make possible the production of thousands of pounds of magnesium per day at pressures less than 1/ r0,000 of an atmosphere. Pilot-plant operations have been consistently maintained at pressures even as low 2s one micron (0.001 mm.). These low pressures, which previously were regarded as prohibitively costly or impossible to attain, have been demonstrated as economically feasible on an industrial scale. Necessity for Vacuum The main function of vacuum in the ferrosilicon process, and hence in most vacuum smelting processes, is to lower the temperature at which the metal may be distilled or sublimed from the reduction mixture. A secondary function is to protect the distilled metal from attack by the furnace atmosphere and to permit the formation of a dense condensate. In the ferrosilicon process, magnesium is formed by the reaction between dolomite and ferrosilicon: 2(Mg0-Ca0) -\- HFeSU / t=> aMg + MFe + (CaO)2-SiO2 The metal is distilled from the pelleted charge at a free air pressure of about 0.100 mm. of mercury (100 microns). This low pressure is not needed for the reaction, but rather serves to protect the metal vapor from the oxygen or nitrogen of the atmosphere and permits the formation of a condensate free of pyrophoric material. The reaction proceeds at air pressures as high as several millimeters of mercury, and evidence has been offered to show that the actual equilibrium pressure of magnesium at operating temperatures of 2I50°F. is somewhat higher. Experimentation indicates that the yield begins to decrease at pressures above 500 microns. While no real operating data are yet available on the relationship between

Jan 1, 1944

By Enid C. Plante

INTRODUCTION To extend our knowledge of the flotation behavior of sulphide minerals, the response of the following minerals to ethyl xanthate as collector was studied by captive bubble and cylinder flotation tests: antimonite (Sb2S3), arsenopyrite (FeAsS), covellite (CuS), marcasite (FeS2), orpiment (As2S3), pyrrhotite (FeS) and tetrahedrite (4CU2S, Sb2S3). Lollingite (FeAs2) was also examined to determine if its behavior could be correlated with that of pyrite or marcasite (FeS2). EXPERIMENTAL METHOD Mineral for Flotation and Contact Tests Mineral was prepared in the manner already described' and its behavior both freshly ground and "oxidized" was studied. Tests in which the mineral was allowed to oxidize for various periods showed that a uniform response to xanthate was reached in two days or less. Oxidation Products The soluble oxidation products from most of the above minerals were measured and their effect on the flotation of the mineral studied. The mineral samples were wet ground to minus-52 mesh and deslimed, and 20 g of this material placed in 200 ml of distilled water of a measured pH value, and C02 free air bubbled through each suspension at a constant rate (about 1 bubble/sec) for 5 days. It has been shown1 that the size of the mineral is unimportant in the rate of formation of oxidation products and that probably the supply of oxygen to the mineral is the rate-determining step. At the end of 5 days the pH value of the supernatant liquid was measured again, the mineral filtered off and the soluble products determined. Methods for estimation of sulphur acids, ferrous and ferric iron and copper have already been described.1 No satisfactory method was found for antimony. Arsenic was estimated as the arsenate.2 FLOTATION OF "UNOXIDIZED" MINERALS WITH ETHYL XANTHATE AS COLLECTOR Fig I to 3, 4, 6, show the effect of alkali and cyanide as depressants for the minerals with 25 mg potassium ethyl xanthate per liter as collector at 35°C. Wark and Cox3 have shown that with ethyl xanthate as collector, galena, pyrite and chalcopyrite show a greater tolerance to cyanide and hydroxyl ions at room temperature than at 35°C. Covellite (Fig I), marcasite (Fig 2) and pyrrhotite (Fig 3) behave similarly. The independence of the curves for pyrrhotite at 35°C with respect to cyanide

Jan 1, 1947

By Robert Goodwin, Frank R. Milliken

In September 1937, the Ohio Copper Co. inaugurated the treatment of its copper-bearing mill tailings at Lark, Utah. These tailings had been accumulated during the regular operation of the Ohio Copper mine and mill over the period 1907 to 1919. Gravity concentration had been employed except for a comparatively short period in 1919, when flotation was used. The ore milled during that period assayed about I per cent Cu. The chief copper mineral, chalcocite, was disseminated in a shattered quartzite, mainly along fracture or cleavage planes. The quartzite gangue was extremely hard and grinding to liberation resulted in excessive sliming of the "sooty" chalcocite, with consequent high tailings losses. Recovery on the seven million tons treated was probably less than 60 per cent of the total copper content. As early as 1918, attempts had been made to sample the dump. In 1928, a complete sampling program was undertaken. The sampling consisted of seventy-four 5-in. post auger holes drilled to the full depth of the dump at regular intervals of 250 ft. Each 10-ft. portion thereof comprised a sample for analysis. Each sample was screened, rolled, divided into three parts, dried and assayed. The reject was retained for testing purposes. From the depth of the auger holes a contour map of the dump was plotted, Fig. I, which gives percentages of tonnage and copper content. The tonnage within the limit of the drill holes was estimated at about five million tons with an average content of 0.42 per cent Cu, 31 per cent of which (0.13 per cent) was acid-soluble. A screen analysis of the composite dump sample is shown in Table I. Flotation tests by several companies and individuals were then made, the results of which ranged from 62 to 74 per cent recovery. On the basis of these, a 200-ton pilot plant employing straight flotation was built and operated for a few months. Operation of this plant was unsuccessful, as no provision had been made to handle the copper-bearing solutions resulting from the water-soluble copper, a point that was overlooked in the laboratory test work. Attempts to decant the copper-bearing solution for precipitation in the usual manner ahead of flotation were not satisfactory because of low water recovery (owing to poor settling characteristics of the pulp) and contamination of the copper precipitate with unsettled slime. Low copper prices in 1931 necessitated the termination of testing. With the stimulus of higher copper prices in 1937, a review was made of metallurgical

Jan 1, 1943

HAVING previously told you about lodestone, azure, emery, and manganese, things that perhaps belong more properly to the stones than to the metals, the desire has come to me to describe rock crystal as well and, with this, some of the better-known gems, although they are things that are not classified with metals, as far as I know, or even with the serniminerals. In truth, they are neither one nor the other, but they are stones and have the nature of stones. But let them be what they may, in order to avoid straying from the subject we have begun, we shall say that they have mineral properties in their species, as for instance, in respect to their colors. It would seem an error to me if, while I am giving you information on so many other useful things, I did not give you this as well, if for no other reason than because it is a fine accomplishment for a gentleman to have some knowledge concerning gems. Thus since I have proposed to do this, beginning to speak of crystal, I tell you that it is a lustrous, transparent, and limpid stone, composed by Nature with a predominance of wateriness. Thus, contrary to the order of natural things, it has been believed by many that Nature has generated it of pure water by means of a powerful and continuous coldness that always exists in those mountains and places where it is found, for the waters and snows can never melt there because of the great cold. They have tried to prove this opinion of theirs by saying that crystal still retains the nature of frozen water, and that this is. shown not only in its appearance but also in the fact that, like ice, it floats without sinking to the bottom when it is put in water. They also say that it is customary to put it under the tongues of the thirsty on account of the, coldness and moistness which it gives, and that it quenches the dryness of their thirst. But even if all these things were true, as they are not, they do not upon consideration bring us to the conclusion that it is water, because the diamond and the beryl would do the same. Therefore it does not seem to me credible [391 that it is as they claim, for it is a stone generated as such by Nature. And then, if this were true in those places where it rains often and many snows are formed, and these should freeze and never melt but

Jan 1, 1942

By E. DeGoyler

The Furbero oil field lies in the Gulf coastal plain of Mexico between the important ports of Tampico and Vera Cruz and about one-third of the distance between the two points from the latter (Lat. 20" 22' N., 97" 30' W. Gren.). It is in the State of Vera Cruz, about 14 miles west by south of the village of Papantla in the canton of the same name, and is the most southern of the developed oil fields of the Tampico-Tuxpam region being a distance of 50 miles south by east from the Potrero del Llano field and 42 miles in the same direction from the Alamo field. The field has been developed by the Oil Fields of Mexico Co. and is in the midst of a large block of lands owned or leased by them. Communication is through the port of Tuxpam with which it is connected by a narrow-gauge railway and 6-in. pipe line some 52 miles in length. This field is of more than ordinary interest since it represents a type of oil deposit hitherto unknown. So far as I am aware, no other commercially valuable deposit of oil is known to occur under conditions of accumulation similar to those found here. The igneous nature of the so-called 'sand' encountered in drilling was not recognized until a number of wells had been drilled; and it was not until recently that the geological relations of the sill or laccolith, which gives rise to the accumulation of oil, were known and the so-called 'anticline' was known to be, in part at least, the result of igneous intrusion. Geological surveys in this general region were made in 1900-1901 by W. H. Dalton and in 1907-1909 by P. C. A. Stewart, F. W. Moon, Leonard V. Dalton, and Dr. Max Muhlberg. More recent surveys have been made, however, under the direction of the author, by E. L. Ickes, B. C. Belt, B. Hartley, and Harve Loomis. Notes of the earlier examinations were not available with the exception of the report by Dr. Muhlberg who apparently first recognized the true nature of the Furbero intrusion. This paper is indebted to his work and that of the more recent surveys for much of the detail regarding stratigraphy and to Messrs. Percy Furber and Arthur C. Payne, President and General Manager of the Oil Fields of Mexico Go. for permission to publish, and for much of the in-

Jan 1, 1916

By J. Gordon Parr, D. H. Polonis

High purity alloys of titanium and iron, made by a technique of levitation melting, have been investigated with particular reference to martensite formation and decomposition in the hypoeutectoid range. A preliminary study has been made of the occurrence of the phase corresponding to the structure Ti2Fe. MANY of the previous investigations of Fe-Ti alloys have been made using Kroll sponge as a source of titanium; and the subsequent heat treatments to which alloys have been subjected has, on occasion, led to further contamination. Worrier,',' who suggested a part of the equilibrium diagram for the binary system, and Wallbaum and coworkers,3-5 who worked largely with iron-rich alloys, all used Kroll sponge. Van Thyne, Kessler, and Hansen,6 in their determination of the equilibrium diagram, used iodide titanium for alloys up to 30 pct Fe. Duwez,7 who measured the M. temperature of titanium binary alloys with many solute elements, used iodide titanium in all cases except in his work on Ti-Fe alloys for which he used Kroll sponge. The investigation of the supposed phase Ti2Fe by Rostoker8 nvolved the use of iodide titanium. A section of the constitutional diagram, after Van Thyne et al., is reproduced in Fig. 1. Frequently too much stress is placed on the effect of contaminants in equilibrium and nonequilibrium systems, but there is no doubt that titanium alloys are extremely susceptible to interstitial atoms. Consequently, the main purpose of the work to be described was to determine those features of phase transformations in pure Ti-Fe alloys that were considered of importance in commercial heat treatments. For, although commercial alloys may not be of high purity, the investigation of a system uncomplicated by traces of impurity is a desirable starting point. Another incidental feature, the occurrence of Ti2Fe, was also investigated. The entire study was carried out using powders obtained from alloy ingots, for diffusion reactions are often more rapid in small particles than in bulk specimens. The frequently adopted practice of ascertaining phase constitutions by X-ray analysis of powders, and relating these to the microstructures and mechanical properties of bulk specimens, is considered by the authors to be open to criticism. In the martensite reactions in the Fe-Mn system, for example, it has been shown- hat similar phase distributions in solid and powder may result in different hardness values and appearance under the microscope; and it is possible that similar anomalies might occur in the Ti-Fe system. Consequently, in order to

Jan 1, 1955

By W. E. Rice

The ceramic industry has to do with forming or molding articles of clay, and imparting to them their characteristic properties of permanence, strength and color by subjecting them to heat treatment in kilns. This heat treatment is commonly known as "firing" or "burning." The art of firing clay ware antedates the industrial use of coal; hence wood was the fuel first used, and the earliest kilns were built to burn wood. The majority of the clay ware produced today is fired in periodic kilns that are essentially enlarged structures similar to the earliest enclosed kilns; a kiln consists of a large chamber 16 to 32 ft. dia. (or rectangular) in which the ware is charged and fired either in direct contact with flame or hot gases from the fuel, or in saggers which shield the ware from direct contact with the gases. The fuel is burned in a number of small furnaces built in the thick wall that encloses the chamber; these furnaces are from 16 to 36 in. wide and from 3 to 5 ft. long; some of them have horizontal or sloping grates, but many have no grates; the last are called "dead-bottom" furnaces. The temperature necessary to mature the charge in the kiln varies for different clays; for some it is as low as 1800°, and for others as high as 2700" F. Wood was an ideal fuel for the low temperatures that were used in early kilns; it burns freely and produces a long, clean flame, which promotes uniform distribution of the heat in the kiln; it does not coke and so restrict the passage of air through the fuel bed; the ash does not melt in the fuel bed to form clinker; and the ash that is carried into the chamber and deposited on the charge does not contain iron and sulfur to discolor the clay. The extent of the ceramic industry now precludes the general use of wood in kilns, so that today this industry is one of the large users of bituminous coal, burning more than eight million tons annually in kilns. Manufacturing plants usually are at or near the source of clay, with deposits of coal suitable for kilns occurring near the clay. The cost of coal is the largest single item of expense in the manufacture of clay ware, and, because all coals are not equally suitable for the process, the careful selection of coal is important. In this selection the desidera-

Jan 1, 1932

By Fred Wise, C. W. Wark

The Getchell mine, a comparatively recent gold discovery, is in the old Potosi mining district, Humboldt County, Nevada. All ore is mined from open pits using Diesel shovels and gasoline trucks. Two types of ore are mined, oxide and sulphide. Oxide ores are siliceous or shaly; sulphide ores either gougy, siliceous or shaly. In mining, the sulphide ore is segregated into hard and gougy ore, because the gouge must be dried before it can be crushed. The oxide ore is not segregated. General Metallurgy The oxide ore is the leached outcrop that overlies the sulphide ore body. All of the iron and arsenic sulphides found in the sulphide ores have been thoroughly oxidized. The sulphur and arsenic have been leached out while the iron is present as hematite and limonite. The oxide ore is amenable to direct cyanidation, and although no visible free gold is present it is released at a comparatively coarse grind. The sulphide ore is more refractory, since the gold is all of micron size and some of it is locked in fine sulphides. It has been established microscopically that the free gold is coated with an impervious shell, which is probably some form of iron compound. The sulphide ores contain from 1.5 to 2 per cent of arsenic, which is present as orpiment and realgar with minor amounts of arsenopyrite. The orpiment and realgar are of a later mineralization than the gold and are barren. Roasting and washing of the sulphide ore prior to cyanidation is necessary to eliminate , the arsenic, to alter the gold coating from an insoluble form to a soluble form, and to release the gold associated with the fine sulphides. Washing the ground calcine in weak sulphuric acid, trona, or hot water are beneficial in the order named, but to date the water is the best from an economic standpoint. Metallurgical tests as well as plant practice indicate that a certain amount of gold cannot be recovered even by going beyond economic practices. On this basis metallurgical results are viewed in the light of an optimum tailing rather than a percentage of extraction. Milling Practice Crushing (Fig. I).—There are three primary ore bins, one each for oxide ore, gougy sulphide ore, and hard sulphide ore. In front of each bin a substantial yard is maintained, which makes it possible to Stockpile 2500 tons of oxidized ore, 1000 tons of hard sulphide ore, and 1000 tons of gougy sulphide ore. The bins are fed by a 60-hp. caterpillar bulldozer from the stockpiles. Fig. I shows the method and

Jan 1, 1943

By O. N. Cole, R. E. Davis, T. D. Brotherton

Pvfoperties of rubidium and cesium are compared with those of other alkali metals. Methods for the preparation of rubidium and cesium metal are reviewed briefly, ad hazards and safety precautions required in handling rubidium and cesium metal are described. SimPle methods for handling laboratory quantities of elemental rubidium ad cesium under oil and under argon are illustrated. CESIUM and rubidium were both discovered by Bunsen and Kirchoff in the years 1860 and 1861. Cesium was discovered while Bunsen and Kirchoff were making a spectrographic study of spring water from Durkheim, Germany. It was the first element discovered by this technique. The element was given the Latin name "caesius" for sky blue because of the color it imparted to flames. Elemental cesium was first prepared by Setterberg in 1881 through electrolysis of a molten mixture of cesium and barium cyanides.' In 1861, Bunsen and Mirchoff discovered rubidium while making a spectrographic study of the alkali content of lepidolite ore from Saxony. Two prominent dark red lines appeared in the spectrum and so the element was named "rubidius" or dark red. In 1861 Bunsen and Kirchoff first prepared elemental rubidium through the electrolysis of molten rubidium chl~ride.~ The alkali metals are very similar in their chemical and physical properties. They are the most active metals, and all exhibit a single oxidation state of one. They are so reactive that they are never found in nature in the elemental state. The reactivity of he metals increases with atomic number. Rubidiurn and cesium ignite spontaneously in air and react explosively with water. This extreme reactivity makes necessary special equipment and techniques for the safe preparation and use of the metals. The cation: of Group IA can be separated from the metallic cations of other groups with relative ease, but the separation of the individual alkali cations is much more difficult because of their close chemical similarity. This close chemical and physical similarity of alkali metals can be inferred from the atomic radii, oxidation numbers, and ioni-zation potentials shown in Table I. A difficult but the most practical physical method of separating the elemental alkali metals from one another is by distillation. Only lithium has a boiling point sufficiently far-removed from the boiling points of the other alkali metals to make this method of separation feasible without elaborate and expensive equipment. This method is not used, however, for lithium because it possesses sufficient chemical dissimilarity from the other alkalies for it to be separated relatively easily as lithium hydroxide monohydrate or as lithium carbonate. Francium, the last member of the group, has no known stable isotopes. The naturally occurring

Jan 1, 1962

R. C. Canby, Wallingford, Conn. (communication to the Secretary*). —Apropos of the experimental reduction of copper from cuprous chloride by fusion with ground limestone and colre, as described by Messrs. Laist and Frick, and also proposed for use at Chuquicamata, it might be of interest to refer bricfly to the experience at Argentine, Kan., in the smelting of the suboxide of copper (as produced in the Hunt and Douglas process) containing appreciable quantities of chlorides. In the Engineering and Mining Journal of June 10, 1911,I gave some account of what had appeared to be crucial difficulties with the Hunt and Douglas process, and how the filter-press difficulty had been so rapidly overcorne after my discovery of the effect of the sodium salts in the leaching solutions. I also described the effect of the cupola-furnace gases upon the lime rock with which I had replaced the coke in the absorption tower, which apparently showed the presence of considerable chlorine, due to the imperfect conversion of the subchloride to suboxide, as well as that due to the difficulties of washing thoroughly the suboxide with the means provided, and also to the presence of chlorides in the cement copper which was smelted with the suboxide. The fumes from the cupola, when issuing direct into the atmosphere, were very dense and white, except when a hot furnace top caused a reddish tinge due to dust. These fumes had a peculiarly suffocating effect, SO that when they were blown over into the town the population suffered the greatest actual distress, not the mere annoyance which would have been due to a disagreeable odor. The absorption tower had been built at the instance of the city authorities to abate this nuisance, and not with the idea of making any additional metal savings. A serious feature in connection with the Argentine experience with the Hunt and Douglas process was, that it had been implicitly assumed that there could be no metal loss in the Hunt and Douglas process itself, and that all attempts to locate the ruinous copper losses which were accumulating in the metallurgical accounts were devoted to the roasting department. It is possibly unfortunate for metallurgical advance along these particular lines that just about the time of this discovery of this previously unsuspected volatilization loss, in the smelting of the suboxide, the Kansas City company made a contract with the Western Union Telegraph Co. for its supply of copper sulphate and the Hunt and Douglas

Jan 1, 1915

By B. M. Larsen, T. E. Brower

INTRODUCTION THIS discussion is based on statistical manipulation and evaluation of operating data from several commercial blast furnaces which include rather wide variations in practice. We are concerned here mainly with the effect of manganese on sulphur elimination under operating conditions in commercial blast furnaces, but this effect can be outlined more clearly by including certain other variables such as silicon in iron and slag basicity, which are all in part interrelated. Real progress in understanding all of the smelting-zone reactions in this process requires more laboratory studies of slagmetal melts similar to those in the blast furnace, with careful control of oxygen pressure. Such experimental work is very difficult, however, and in the meantime, with the present scarcity of more fundamental data, such statistical trends and correlations as can be obtained from commercial furnace operating records may help in choosing laboratory test conditions as well as adding to our knowledge of operating procedures. We do not know just why the furnace data are apparently so irregular that statistical treatment of large numbers is needed to obtain accurate trends. It is .partly caused, no doubt, by the many simultaneous variables present, but there are perhaps also such factors as: (I) the continual swings up and down so characteristic of the process; (2) difficulty of accurate sampling of co-existing phases, as well as (3) the presence of both equilibrium and rate factors as a result of the fast driving of the process, In desulphurization, for example, the flow of thin layers of slag and metal over solid coke surfaces, plus the contact between droplets of iron falling through the slag layer in the hearth, would lead one to expect a close approach to equilibrium, On the other hand, most of the critical part of sulphur removal may occur in a short time and distance below the tuyeres with perhaps an accompanying decrease in oxygen pressure and the concurrent reduction of much of the silicon and manganese, so its degree of approach to equilibrium may be quite variable. PROBABLE CHEMISTRY OF DESULPHURIZATION Since there is little evidence that sulphur atoms in the iron solution are associated to any appreciable extent in molecules such as MnS, the transfer from slag to metal and back again can be written:* [(FeS) -, [FeS],[I] hence the following reactions seem most probable in the slag phase, (FeS) + (CaO) = (CaS) + (FeO), [2] and, (FeS) + (MnO) ;:2 (MnS) + (FeO). [31]

Jan 1, 1948

By Grover J. Holt

A DETAILED description of the many variations in iron mining and transportation practice in Minnesota would require much space. Since a fairly detailed description of the practices then in use was published in the guidebook issued in connection with the meeting of the Institute on the iron ranges in 1920, and subsequent developments have been described by E. E Hunner,1 M. H Barber,2 and A. E. Anderson, J. M. Riddell and G. J. Holt,3 it will not be necessary here to do more than review the highlights of current practice Details on any points of interest can be obtained through correspondence with the operators involved.† The iron ores of Minnesota, which have been formed through enrichment, of the iron formation in which they occur, largely by the removal of silica, are usually covered by a blanket of glacial drift known locally as "surface." Surface material, including sand, clay, hardpan and boulders, makes up the greater portion of the stripping in open-pit operations. In some instances, stripping also includes taconite and "paint rock," directly below the surface material and overlying the ore. Taconite is the iron formation, a ferruginous chert with interbedded slate layers. "Paint rock" is a local term for oxidized slate layers interbedded in the iron formation, high iii phosphorus, alumina and moisture The iron ores fall into two classes- (I) direct shipping (merchantable ores or ores requiring no treatment except possibly crushing or screening to make an acceptable sized product), and (2) ores requiring beneficiation (such as sintering, drying, washing, jigging, high-density treatment, or magnetic separation in the case of magnetite) The Mesabi Range produces chiefly soft Bessemer and non-Bessemer ores. The Cuyuna Range produces mainly low-manganese brown ore and high+manganese black ores, with some iron ore. The Vermilion Range yields mainly Bessemer and non-Bessemer iron ore, with some hard or lump ore that finds use in the open hearth. Open-pit mining is limited to the Mesabi and Cuyuna Ranges but underground mining is done on all three. The choice of mining methods is determined by the relative economics of overburden-removal and shaft-mining costs. STRIPPING PRACTICE Common practice has been to remove the bulk of the overburden during the winter season and to mine during the summer. In the present emergency many operators are forced to forego the economies attained by year-round utilization of equipment and to equip for, and carry on, stripping and mining simultaneously. In the normal years or lean years to come, most properties probably will be overequipped and high depreciation charges will have to be absorbed

Jan 1, 1942

By R. S. McFarland

OKLAHOMA, in 1924, recorded the largest single increase of any state; the total oil production for the year being 176,206,397 bbl. (Oil & Gas Jnl.), which gives an increase over 1923 of about 9 per cent. Oklahoma ranked second in total amount, California being first, and produced almost 25 per cent. of the total production of the United States. This gain in production is accounted for entirely by the rapid development, deeper drilling, and efficient management of productive areas known at the beginning of the year, for, due to the small number of wells drilled, few new pools were discovered and developed up to any important stage during the year. Three major pools, Burbank, Tonkawa and Cromwell, furnished 37 per cent. of the total production. Burbank led by a wide margin, having the largest production of any single pool; there was a steady increase in production until September. The close. development of the pools in Okfuskee, Seminole, and Hughes Counties, together with the new deep-sand production at Tonkawa and increased drilling operations in Osage County, accounted for the big increase shown during the year. In January, 1924, the shutdown movement and curtailment of production in Hewitt and Tonkawa, which had been effective during the year of 1923, were stopped. The shutdown movement and curtailment of operations in 1923 does not give a fair comparison with 1924, as undoubtedly a great deal more oil would have been produced in 1923 had it not been for these measures. The sensational developments during the year, which were certainly beyond the prediction of the oil industry, were the Cromwell field, which started the year with 10,478 bbl. for January and increased rapidly to 1,267,032 bbl. for. December, and the discovery of the Wilcox productions below 4000 ft. in the Tonkawa field in May, which by the end of the year had produced 11,650,000 bbl. In this connection, it can be safely said that 1924 was a banner year for the Wilcox sand series; it has been estimated that between 40,000,000 and 50,000,000 bbl. of the production for the year came from this sand. Although numerous Wilcox pools were opened throughout the state, the big Wilcox production came from. the Tonkawa and Stroud pools. Oklahoma's deepest well, the Kingwood Oil Co. No. 1 Barnett in the northwest corner of the northeast quarter of the southeast quarter of Sec. 7 T. 7 N. R. 10 E., Hughes County, was abandoned in January, at 5281 ft. with numerous good shows recorded, which have stimulated-further drilling in the locality.

Jan 3, 1925

By A. K. Knickerbocker

Practically all underground work on the Minnesota iron ranges is done by miners working on a so-called contract wage system. This system, while it has certain advantages over the straight day's pay or company-account method of wage payment, has serious and vital defects. In view of the scarcity and demands of labor, it is important that employers of labor scrutinize their systems of wage payments carefully, not only to save losses and trouble, due to labor disturbances, but also to secure the greatest efficiency of their workmen and reduce their operating costs. It is admitted that an adequate, just, and equitable wage is the prime factor in bringing about these benefits. The wage of labor and its method of application and payment have been, and always will be, the main factors in the unrest and dissatis. faction of labor. Not only does labor want and need an adequate wage, assuming that work is adequately performed, but it wants and is entitled to a just and equitable wage. Labor must have respect for the fairness of the wage and for the fairness of the management in the application of the wage It is conceded that the Minnesota iron miners are now, and have been, in the main paid adequately, but the inherent defects of the so-called contract system prevent any just or equitable application of this wage to the various units of the labor body. The defects of the contract system, with its obvious inequalities, favoritisms, and injustices, are cancers in the brain of labor. Every thinking miner realizes these defects and knows just what they are; the unthinking do not realize the details of the subject, but each month they are forcibly reminded of these defects through the pay envelope. As practiced on the iron ranges, however, the so-called "contract " system is not a contract and the name is a misnomer. No true contractual obligation exists. As usually practised, the contract system involves the setting of a price per foot in development work, or per foot or per car, usually the latter, in slicing or stoping, by the mining captain, and assumes its acceptance, though often under protest, by the men. A price is set for each working place, in which there are usually two men per shift. This price includes labor and supplies, such as explosives, fuse and caps, shovels, carbide, etc., and the men divide the total earnings less the amount expended for supplies. The cost of the supplies charged to the men varies

Jan 1, 1920

By William F. Ward

One often reads of the rich placer gravels in many of the citnoe-trav-elqd rivers of South America. The apparent richness of these gold-bearing gravels impresses the traveler, and in fact he may see batea after batea showing enough colors to figure over a dollar per cubic yard. These workings are called "playas" from the Spanish word playa, meaning shore or beach. Many workings have been reported in tropical rivers, but to my knowledge no dredge has made a success in such deposits. Investigation generally shows that the area of richness is limited and especially that the depth of the rich concentration is hardly ever more than a few inches. The Cauca river in Colombia, South America, is noted for its many rich playas. This river rises near .Popayan in the southern part of Colombia, flows north through a narrow valley between parallel mountain ranges and empties into the Magdalena river near Maganque. , The airline distance between source and mouth of this river is only about 500 miles. The rainfall is large and the lower Cauca appears to be about the size of the Missouri river in the United States. From its mouth up to Valdivia, in the State of Antioqua, it is navigable. Above Valdivia is a narrow gorge, above which the river is again navigable for some distance. The part of the Cauca where the play a panning is most noticeable is from Valdivia down to where the Nechi river enters the Cauca, a distance along the river of about 100 miles. The current in this part is swift, so that the stern-wheel river steamers make the trip with some difficulty. In the course of my work in this section of Colombia I have had the opportunity to make a study of several of these play a workings and will give in detail the conditions observed. The Island"Playa" The richest of the island playas is about 40 miles below Valdivia and a little below the old town of Caceres. The shape of the river and the location of the deposit are shown in Fig. 1, which indicates the condition at low water. The river at this place is about 600 ft. wide and the island about 75 ft. wide by 300 ft. long. The island is made up of coarse pebbles, some of which are as big as a man's head. In times of high water this island is under several feet of water and in a swift current. When the river lowers the current is still fast enough to prevent sand or silt from covering the coarse pebbles.

Jan 1, 1915

By Emby Kaye

IT is the purpose of this paper to outline briefly some of the considerations that enter into the economics of so-called recycling, the generic designation of the relatively recently developed process by which a condensate† is separated from gas-distillate gas at high pressure and the residual gas returned to the reservoir. This subject necessarily embraces not only a discussion of factors that should be considered in projecting a recycling operation, such as estimating reserves, investment and operating costs, but also a comparison of condensate with other types of petroleum. The place of condensate in its relation to the total supply of crude oil is pointed out as well as certain logical methods of product disposal. The cost of drilling wells and lease maintenance is not pertinent to this discussion because income and revenue are in this paper confined to that retained by the plant or plant operator for supplying processing facilities for the gas. Before the development of recycling a great many gas-distillate gas fields in Louisiana and. Texas provided no income to their owners. When gas was sold from these reservoirs it was accompanied by irretrievable losses of condensate in the formation. The understanding of the function of retrograde condensation resulted in the introduction of a new commercial petroleum recovery process for these hitherto unexploited fields and now permits the conditioning of this type of wet gas field for the sale of dry gas therefrom without waste. SOME ECONOMIC FACTORS The study of a gas-distillate field for possible exploitation necessarily involves the critical appraisal of a number of elements, chief of which will be discussed here: (I) estimate of distillate in place, (2) estimate of distillate that can be brought to the surface, (3) available market, (4) costs. The considerations affecting the estimating of distillate reserves. in place are in the main subject to the same errors as are involved in determining dry gas reserves. Determinable data including acreage, sand thickness, reservoir pressure, reservoir temperature, porosity and connate water provide the basis for calculating the volume of gas in place. Ample allowance must be made for connate water, which may occupy from 20 to 35 per cent of the pore space of the sand. The factor of supercompressibility is to a considerable extent nullified by the reservoir temperature. It has been considered well advised to allow this factor to serve as a cushion. With the gas reserves calculated, it remains only to assay the distillate content of the gas. Those familiar with the handling of "wet" gas at high pressure readily appreciate the variables in sampling gas from

Jan 1, 1941

By L. P. Teas

Although 1930 has been a year of stagnation, proration and curtailment, the Gulf Coast has measured up to its tradition in the matter of interesting and significant discoveries. Only 2 domes and 7 new structural areas were brought into the producing column in 1930, whereas, in 1929, 13 domes and one structure were added to this list, yet a total of 14 new producing horizons were proved on various domes and structures. On 5 domes new flanks were successfully tested for commercial production. The year 1930 has shown at Barber's Hill that oil in commercial quantities may exist below salt or cap. Numerous wells have been drilled through cap, or even salt itself, into good producing sands. The past year has been particularly notable in the interest and in the number of deep holes drilled. Two wells have gone below 8000 ft. in each of the states of Texas and Louisiana, and in the two states together 14 wells have gone below 7000 ft At the beginning of the year only one well was producing below 6000 ft. in coastal Texas, while at its end, 19 wells were producing or had produced. Geophysical discoveries and activity on the Coast have waned and this type of work has moved further inland. The peaks of production at Pettus, Barber's Hill, Raccoon Bend, Refugio, Orchard and at Humble, in Texas; and at Lake Barre, Port Barre, Black Bayou, White Castle and Vinton in Louisiana, were seen this year. These were new peaks for Humble and Vinton, of course, these fields having previously gone through periods of peak flank production. In Table 1 the completions listed are for the entire month of December in both years. It is remarkable that in 1930, a year of overproduction and proration, there were actually more wildcat operations at its end than at the end of 1929; but it is gratifying that the operations in the proven fields were exactly one-half what they had been at the end of 1929. The price of A grade coastal crude, or oil below 25" Bé., has been cut from $1.30 at the beginning of the year to $1.00 at its close; and B grade, or oil above 25o Bé., has been reduced from a price range of $1.15 to $1.63 down to a range of from $0.75 to $1.22. In spite of these reductions there has been no proration program on the Coast. Systematic

Jan 1, 1931

By J. B. Warriner

S. A. TAYLOR, Pittsburgh, Pa.-What was the distance of haul? J. B. WARRINER.-There is practically no limit to the haul. The length is determined entirely by the feasible location for a dump. -I have known of hauls up to 2 miles in length. R. V. NORRIS, Wilkes-Barre, Pa.-This paper was originally presented to the Anthracite Section as the result of the appointment of Mr. Warriner as the Chairman of the committee to study this matter and present this paper. As he has stated, he obtained data very freely from all the stripping operations in the region, and it is a type of paper of which we should have more in the Transactions. Two or three things in it strike me as particularly valuable. The two tables, 1 and 2, showing the coal remaining, have been the result of a great amount of study, as it is not an easy matter to obtain data as to the amount of coal left in mining. As an example, one of the, anthracite mines was mined and robbed out in 1850, so the maps show. That mine is today producing 250,000 tons of coal, over 50 per cent. from the bed which on the maps is marked as exhausted. What actually happened is that the seam was on a light pitch inconvenient to mine. There was ample thickness of coal and the chambers were driven at a convenient pitch through this 30,-ft. bed, leaving top and bottom, taking out about 10 ft. The pillars were removed and the working caved and marked as gone. That is the type of area that is now being stripped, which explains the reason for the enormous amount of coal left in, and the fact that Mr. Warriner has worked out the actual results from a large number of strippings is of great interest to the operators in any region handling thick coal which has been mined over in the past, generation. The modern mining, of course, is different. We do not have all the coal we want in big veins, and we do not mine it that way. Another interesting feature of the paper to me was the study of losses. It is not uncommon to assume that after you have stripped off the overburden all the coal goes to market. Mr. Warriner has shown that there is a loss ranging up to 10 or 15 per cent. that does not go, so 'that estimates made on stripping, figuring on all the coal, are subject to this very material correction.

Jan 4, 1917