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By Frank G. Miller

The lower cost of producing oil from naturally flowing wells compared with pro-luction costs accruing from artificial lifting methods has stimulated much research, rith the joint purpose of extending the natural flowing life of wells and of increas-ng the productivity of small wells. The iboratory investigation described herein was made to determine the effect of a lotted liner on the pressure gradient in the icinity of the wall of a flowing well. Flow estrictions caused by the liner induce nergy losses between the oil-bearing for-lation and the inside of the liner, which lay be reduced by improved liner design, nd thereby the flow capacity of wells may e increased. These losses have been evalu-ted for rectangular slots of different sizes, nd means are suggested for reducing them. The dearth of information concerning the ature of the flow of fluids from uncon-slidated sands through small openings in he walls of. pipes—as represented by the ow of oil from an oil sand into a slotted ner—is acknowledged. Although the bene-ts to be realized by operators through the se of optimum liners is just beginning to e recognized generally, Coberlyl in 1937 ointed out that the functioning of screen is is an important factor in the pro-uction of oil. From his study on the :lection of size of oil strings for wells in California, Parks2 concluded, in part, that the perforated section of the oil string deserves continued study, especially with respect to the selection of perforations. The growing use of gravel packing resulting from certain research findings lends even more significance to the problem of selecting optimum liners, as the application of these methods usually requires slotted liners or other kinds of perforated liners. The present study was made to obtain further information for the guidance of engineers and operators in selecting slotted liners and to develop a laboratory method that may be used in analyzing possible pressure conditions surrounding most types of perforated casings used in producing oil wells, so that the present inadequate fund of knowledge on this important subject may be expanded. Discussion of ProbleM At the beginning of the investigation the following assumptions were made regarding bottom-hole conditions of a producing oil well and the oil-sand reservoir it penetrates: (I) Conditions of steady-state flow exist, (') a a homogeneous liquid is being produced) (3) no contaminating material (such as drilling fluid) is present between the liner and the face of the oil-bearing sand, (4) the well is vertical and completely penetrates a horizontal sand stratum of uniform thickness occurring between two impermeable strata, and (5) the flow is wholly viscous. If the foregoing assumptions are made, with the added requirements that the sand

Jan 1, 1941

By Donald W. Scott, Adam Wesner

This paper describes the study of 23 nonmagnetic iron-formation samples from the Mesabi Range and shows the significance of their chemical, mineral, and physical properties in terms of their concentration. Data presented here resulted from a research project carried out from 1942 to 1952 by 10 major producers of iron ore, working in conjunction with Battelle Memorial Institute. THE inevitable depletion of Mesabi direct-shipping iron ores, hastened by recent wars, has increased the importance of developing methods to concentrate iron-formation materials. Many mining companies, independent research organizations, chemical companies, and equipment manufacturers are devoting attention to this important work. It is only natural that magnetic iron-formation materials have received major emphasis, since magnetic recovery methods apply and reserves of Mesabi magnetic taconites are large. However, the nonmagnetic* iron-formation materials are likewise believed to represent a large reserve and their study has not been neglected. tions over the years have shown that in addition to the unenriched taconite, which is dense and hard, and the direct-shipping ore, there are transition taconites grading into the friable wash, or intermediate ores. The transition taconites are less massive than the unaltered taconites and usually coarser-grained. This variation, coupled with the fact that there were no extensive drillings in the unaltered taconite, posed a most difficult problem of obtaining samples that would be representative of large tonnages of the fresh rock. The problem was increased by the tremendous extension of the nonmagnetic formation materials on the Mesabi and by the question of their accessibility to mining. A drilling program was evolved that would surmount these difficulties. Selection of samples was made by a committee representing producers in the area. The samples were procured from 1—taconite walls near bodies of stripping burden or wash ore and 2—from shafts in the process of being sunk through taconite for drainage or mining operations. Most of the samples were obtained from the cherty horizons because it became obvious early in the program that the slaty horizons represented an exceedingly difficult concentration problem, owing to the character of the gangue minerals and the fine grind required for liberation of the valuable minerals. More samples were procured from the lower cherty horizon than from the upper cherty because it was more accessible to mining. It is not known how well the samples selected represent the nonmagnetic iron-formation material. However, they were chosen by people Well acquainted with the geology of the Mesabi range and the mining problems involved. It is believed that they represent a fair cross-section of the types of materials that will be encountered. Table I gives data on the origin of the 23 samples and the horizon footages from which they were obtained. Samples 1 through 10, and 15 and 16

Jan 1, 1955

By Walter E. Duncan

The ores treated at the concentrating plant of the Mahoning Mining Co. at Rosiclare, Ill., come largely from the blanket replacement deposits of the northeastern part of Hardin County, Illinois, and consist of complex mixtures of galena, sphalerite and fluorspar in a gangue of quartz, limestone and sandstone. The several minerals are so intimately inter-grown that they are not liberated at the sizes usually treated by gravity concentration in the usual fluorspar plant. For this reason, an all-flotation method of concentration was developed in cooperation with the station of the U. S. Bureau of Mines at Rolla, Mo.1 This flotation separation made possible the commercial production of four coyentrates: (I) lead, (2) zinc, (3) acid-grade fluorspar and (4) metallurgical-grade Auorspar.2-3 Although fluorspar had been floated in Canada in 19214 and a plant at Rosiclare had been floating fluorspar since March 1929, fluorspar flotation was given considerable impetus by the Mahoning developments, since some features of the separation were quickly adopted by other fluorspar companies. The Bureau of Alines5 reports that in the 10 years preceding 1938 only 50,552 tons of fluorspar flotation concentrates were produced in the United States. The rise from this almost nominal figure to 153,750 tons (largely acid grade) in one year (1944)6 is indicative of the activity in fluorspar flotation occasioned by the war. The industry thus proved to be in a position to expand and keep up reasonably well with the requirements imposed upon it by such developments as occurred in high octane aviation gasoline alkylation, in the use of Freon as a refrigerant and as carrier in the Aerosol "bug bomb," and in the atomic bomb project as well as in the expansion of other activities requiring hydrofluoric acid; for example, the aluminum industry. Despite the fact that the greater portion of acid-grade fluorspar produced in the last few years went directly into war uses, the future of the acid-grade field still appears bright. As a result of the activity in fluorine chemistry during the war, it seems likely that in the relatively near future almost every phase of human endeavor will find some fluorine compound involved. The other three concentrates produced deserve some attention in these introductory remarks. The lead concentrates first produced contained both zinc and fluorspar but these did not interfere with their marketing. As will be pointed out later, the quality has steadily improved until today it is a relatively high-grade product. Although some zinc smelters accept concentrates containing limited quantities of fluorspar, it is a very objectionable impurity. Since flotation methods fail in the complete removal of the fluorspar, chemical methods were developed for

Jan 1, 1948

By Walter E. Duncan

The ores treated at the concentrating plant of the Mahoning Mining Co. at Rosiclare, Ill., come largely from the blanket replacement deposits of the northeastern part of Hardin County, Illinois, and consist of complex mixtures of galena, sphalerite and fluorspar in a gangue of quartz, limestone and sandstone. The several minerals are so intimately inter-grown that they are not liberated at the sizes usually treated by gravity concentration in the usual fluorspar plant. For this reason, an all-flotation method of concentration was developed in cooperation with the station of the U. S. Bureau of Mines at Rolla, Mo.1 This flotation separation made possible the commercial production of four coyentrates: (I) lead, (2) zinc, (3) acid-grade fluorspar and (4) metallurgical-grade Auorspar.2-3 Although fluorspar had been floated in Canada in 19214 and a plant at Rosiclare had been floating fluorspar since March 1929, fluorspar flotation was given considerable impetus by the Mahoning developments, since some features of the separation were quickly adopted by other fluorspar companies. The Bureau of Alines5 reports that in the 10 years preceding 1938 only 50,552 tons of fluorspar flotation concentrates were produced in the United States. The rise from this almost nominal figure to 153,750 tons (largely acid grade) in one year (1944)6 is indicative of the activity in fluorspar flotation occasioned by the war. The industry thus proved to be in a position to expand and keep up reasonably well with the requirements imposed upon it by such developments as occurred in high octane aviation gasoline alkylation, in the use of Freon as a refrigerant and as carrier in the Aerosol "bug bomb," and in the atomic bomb project as well as in the expansion of other activities requiring hydrofluoric acid; for example, the aluminum industry. Despite the fact that the greater portion of acid-grade fluorspar produced in the last few years went directly into war uses, the future of the acid-grade field still appears bright. As a result of the activity in fluorine chemistry during the war, it seems likely that in the relatively near future almost every phase of human endeavor will find some fluorine compound involved. The other three concentrates produced deserve some attention in these introductory remarks. The lead concentrates first produced contained both zinc and fluorspar but these did not interfere with their marketing. As will be pointed out later, the quality has steadily improved until today it is a relatively high-grade product. Although some zinc smelters accept concentrates containing limited quantities of fluorspar, it is a very objectionable impurity. Since flotation methods fail in the complete removal of the fluorspar, chemical methods were developed for

Jan 1, 1948

By Harry H. Power

The Specific purposes of forma! engineering education include training in the basic sciences, the engincering-prob]em method, the rudimentary development of technical skills, an appreciation of values and costs, and an understanding of the art of engineering as distinguished from its science, Two major divisions of an educational program in engineering are recognized: (I) the scientific-technological, and (2) the humanistic-social. Hence, the entire curriculum for the four-year program in specialized petroleum engineering schools must be designed to give the student an initial impetus in the directions indicated. In accordance with suggestions from the Engineering Council for Professional Development, Inore attention is being given to the fundamental approach in the undergraduate curriculum. This paper presents a cross-sectional viewpoint of the various educators in the petroleum engineering schools concerning course contents in the specialized curricula An outline is suggested for the content of the specialized courses wherein the engineering problem method or quantitative approach is emphasized. Although the particular viewpoints of the author have been stressed, yet due acknowledgment is made to a considerable number of petroleum engineering educators and in in industry interested in educational work, for their contribution of course outlines or helpful suggestions with respect to programs that will be of maximum value to students, institutions, and the industry they serve. Although "standardization" of course material is not suggested, the advantage to be gained by cooperative determination of purpose and scope are apparent paiticular1y from 'he standpoint of the proper accreditment of petroleum engineering schools by petroleum engineering educetors who have laid a basis from which to measure educational values. Petroleum engineering has "come of age" and deserves the same careful attention with respect to. curricula that has been accorded other engineering branches. Introduction Engineering schools have a major responsibility to the public, to industry and to the professions they serve. The specific purposes of formal education include training in the basic sciences, the engineering-problem method, the rudimentary development of technical skills, an reciaciation of values and costs, and an understanding of the art of engineering as distinguished from its science. Other purposes implied include the ability to read, write, and speak the English language effectively, an understanding of social and human relationships, a knowledge of the duties of citizenship, a broad appreciation of cultural interests, and an indoctrination in professional standards and relations. Throughout these educational processes is the development in the student of habits of accuracy, thoroughness, powers of analysis, creative ability and integrity with respect to all phases of his work. Major Divisions of Program In the Report of the Society for the Promotion of Engineering Education,† two † Report of Committee on Engineering Education after the War, dated January 1944.

Jan 1, 1945

By E. A. Gulbransen, W. S. Wysong, K. Andrew

The reaction of carbon in solid solution in a metal with the surface oxide fim on many metals may be inferred from thermo-dynamic calculations for high vacua and high temperature conditions. Holm has recently shown that oxide films may be removed from ferrous materials by heating in a vacuum at high temperatures and that carbon is the essential element in the reaction. considerable work has been described in the literature on the de-carburization reaction. Several general references may been 2,3,4 However, the nature of the mechanism involved in the decarburization is not well understood. Our interest in this reaction resulted from many attempts to degas and to reduce by pure and dry hydrogen the surface oxides on strips of various types Of chrome-nickel alloys. Some of the early experiments On the behavior Of '3 pct chrome-iron in vacua of the order of 5 X lo' mm and at a temperature Of 600°C have been reported.5 These experi-merits showed a 'low reaction with the residual Oxygen Or water vapor in the system and no reaction with hydrogen. This is in accord with thermodynamic data which would lead to the prediction that it is extremely difficult to maintain a hydrogen atmosphere at 600' C pure enough to reduce Crz03 formed On the surface. The crystal structure of the superficial oxide film formed on 13 pct chrome- iron and Nichrome V has been investigated in the thin film range by Gulbransenr Phelps and Hickman,' and shown to be "203. It Was surprising to us to note that when a specimen of Nichrome V containing approximately 80 pet nicke1 and 20 pet chromium was heated to 850°C in a high vacuum, the specimen lost weight. The rate Of weight loss was very temperature sensitive. A study of this reaction in vacua and in a hydrogen atmosphere is the subject of this communication. Type Reactions Let us consider the various reactions which may occur when a metal is heated in vacua, in a hydrogen atmosphere, or in an oxygen atmosphere. The number and kind of reactions will depend upon the chemical nature of the metal, its alloying constituents and the location of the alloying constituents. The metals used in this study are chrome-nickel alloys of the heater type, They consist essentially of chromium, nickel and iron, small amounts of carbon, silicon and manganese and traces of zirconium, calcium, aluminum and magnesium. The trace elements are added to improve the lifetime and other characteristics of the alloy when used as a heater. Seven of the more important reactions with which we are going to be concerned here are as follows: 1. Metal . (gas) F? metal + gas — degassing of the metal 2. zM(s) + y }i Oi(g) M MIOu(s) -oxidation

Jan 1, 1949

By Rollin Farmin

Rock pressure against the supports for underground workings in certain mines becomes sufficiently severe to crush sound timbers. The cost of maintenance of these mines increases critically as the workings are extended. "Heavy ground " and "swell-jng ground" are terms commonly applied to a condition of excessive pressure from the wall rock. Defined for the purposes of this paper, "heavy ground" delivers gravi-tative pressure on the supports of a mint opening; "swelling ground" delivers pressure arising from expansion of the wall rock. Mining problems created by heavy ground have been studied extensively by mining engineers, as in the recent Symposium on Block caving.' A parallel study of rock bursts2 attacks the field of ground that ruptures under strain. The problem of swelling ground, which has received less current attention, is the subject of this paper. An ExaMPLe of Swelling Ground Severe cases of swelling ground are found in the gougy shear zones in mines along the western Sierra Nevada, where the veins are accompanied by faults through altered serpentine, schist and slate. For example, along troublesome stretches in the ldaho Maryland mine, Grass Valley, California, swelling ground continues to crush drift timbers, with diminishing intensity, for 3 to 10 years after entry. During this period, from five to nine generations of crushed timber sets must be replaced and a large additional tonnage of scaly rock and wet gouge must be removed from the drift to make room for this succession of new timbers. After "the squeeze has been taken out of the ground" the timbers will stand for years, until they collapse from decay. Heaving of floor and footwall along drifts develops soon after the timber sets are placed and frequent grading down of the track is necessary to keep it serviceable and to maintain headroom. If sills are placed under the drift posts, the sets break more quickly and the track becomes impassable at once. When the floor is left Open? and the bottoms of posts and stulls are pencil-pointed, the scaly ground of the fault zone swells up around the timbers (Fig. I) instead of breaking them (Fig. 2). A foot or two of this encroaching ground is trimmed from the floor and lower sides of the drift several times before complete retimbering is necessary. when a set of timber fai1s under the Pressure of swelling ground, there is no immediate fall of timber and broken rock to fill the drift, as is customary in heavy, caving ground. Instead, ground swelling from sides, top and bottom gradually closes the opening, over a period of weeks or months, and no especial hazard to workmen is present while they have room to walk through the narrowing drift. Most

Jan 1, 1946

By C. A. Hartnagel

The year 1944 marks the eightieth anniversary of the discovery of petroleum by drilling in New York State. It was in 1864 that a half dozen shallow wells were drilled at Limestone in Cattaraugus County, in a region that now forms the northern extension of the 82,000-acre Bradford pool. These early wells found oil, but not in paying quantities. They did, however, attract attention to the district and were a factor in the development of the still active Bradford pool of Pennsylvania and New York. During 1943, the production of petroleum in New York amounted to 5,029,000 bbl. This represents a decrease over the previous year, in which 5,421,000 bbl. was produced. The flush production for the New York fields occurred in the early eighties shortly after the discovery of oil in the Richburg pool of Allegany County. During the flush period, production was in excess of five million barrels annually. By 1887, however, the output had decreased to an amount only slightly more than two million barrels, and through the early years of the present century the annual total was often less than one million barrels. Flooding of the oil sands for increasing productioil was made legal in 1919, and in 1927 the output once more reached the two million mark. Two years later it had increased to over three million barrels. In Table r is shown production since 1935, in which year for the first time the output under flooding methods was in excess of four million barrels. From this table, it is evident that oil production in New 'I'ork is rather well stabilized, and since most of the oil is obtained by the flooding, or water-drive, method, with little or no prospect of discovery of new oil territory, rapid changes in yield from year to year are not to be expected. In thickness, the oil sands have a maximum of about 50 ft., and by means oi flooding may produce 10 to 12 thousand barrels an acre and proportional amounts for thinner sands. In some cases, floods have been developed in sands only 12 ft. thick. Under good flooding conditions a yield of 2000 bbl. an acre is about the lower limit at which oil can bc produced at the present price of $3.00 a barrel. The average cost for the physical development ol a lease, not including the cost ol the lease itself, is $5000 an acre. Since several months must intervene before the flood begins to act on the oil wells, and a year or more is required to bring thc wells to maximum daily production, it is evident that a considerable interval occurs before maximum returns are realized. Once a flood is developed and the wells

Jan 1, 1944

ANYONE who wishes to make the patterns for statues in order to cast them later in bronze, even though he himself is the artificer who made them, must take many things into consideration: first, whether they are large or small, and whether they are wholly round or only in part; then of what material they are made, for the way that can be followed if they are of wax cannot be used if they are of clay, wood, marble, or even of plaster; likewise he must consider whether or not it has irons inside to support it. There is also a great difference in facility if the support is placed more in. one way than in another. Great consideration should be given to whether it is to be made hollow or solid. If you have not been the workman yourself, you must at least have been an active helper in this and in every other part in order to be able to observe everything without a fault. For if they are large it is necessary to make their moulds in pieces, with marks and measurements so that you can replace them-at will exactly in the same order and in the same places after they have been taken out. But if you are the artificer [as well as sculptor] the process is made easier. Taking the ordinary way and, over an iron, make out of well beaten moulding clay, compounded with cloth clippings a core exactly as the statue is to be or however large you wish the hollow to be. Dry and bake it. On top of this work the wax, thickening it all over as much as you wish the bronze to be and finish it completely, remembering to arrange that the base may come out solid with bronze so as to support the whole work. Then take some rods of hammered bronze one dito thick and one palmo long. Pass these throughs the thickness of the wax and fasten them in several places in the core of clay that you made. [81] Do it so that they, project out of the wax a good three or four dita. These are, put in so that when the wax is removed the core is held in the middle of the mould that forms the outer part, and this outer part is held by the inner part, namely the core, so that the mould may not move in any part from its place even when it is handled. This done, take some of that clay made with well-prepared cloth clippings as I taught you, and mix with it if you wish some wash ashes or

Jan 1, 1942

By C. A. Hartnagel

The year 1944 marks the eightieth anniversary of the discovery of petroleum by drilling in New York State. It was in 1864 that a half dozen shallow wells were drilled at Limestone in Cattaraugus County, in a region that now forms the northern extension of the 82,000-acre Bradford pool. These early wells found oil, but not in paying quantities. They did, however, attract attention to the district and were a factor in the development of the still active Bradford pool of Pennsylvania and New York. During 1943, the production of petroleum in New York amounted to 5,029,000 bbl. This represents a decrease over the previous year, in which 5,421,000 bbl. was produced. The flush production for the New York fields occurred in the early eighties shortly after the discovery of oil in the Richburg pool of Allegany County. During the flush period, production was in excess of five million barrels annually. By 1887, however, the output had decreased to an amount only slightly more than two million barrels, and through the early years of the present century the annual total was often less than one million barrels. Flooding of the oil sands for increasing productioil was made legal in 1919, and in 1927 the output once more reached the two million mark. Two years later it had increased to over three million barrels. In Table r is shown production since 1935, in which year for the first time the output under flooding methods was in excess of four million barrels. From this table, it is evident that oil production in New 'I'ork is rather well stabilized, and since most of the oil is obtained by the flooding, or water-drive, method, with little or no prospect of discovery of new oil territory, rapid changes in yield from year to year are not to be expected. In thickness, the oil sands have a maximum of about 50 ft., and by means oi flooding may produce 10 to 12 thousand barrels an acre and proportional amounts for thinner sands. In some cases, floods have been developed in sands only 12 ft. thick. Under good flooding conditions a yield of 2000 bbl. an acre is about the lower limit at which oil can bc produced at the present price of $3.00 a barrel. The average cost for the physical development ol a lease, not including the cost ol the lease itself, is $5000 an acre. Since several months must intervene before the flood begins to act on the oil wells, and a year or more is required to bring thc wells to maximum daily production, it is evident that a considerable interval occurs before maximum returns are realized. Once a flood is developed and the wells

Jan 1, 1944

By Fred C. Bond

AN improved method of measuring the surface area of a comminution product down to any desired particle size has been developed. The method is largely graphical, and requires relatively little calculation. It can be used with materials containing large amounts of clay, or excess fines of any kind. The surface area S is expressed in terms of square meters per 100 c.c. of solids. This expression is based upon volume rather than weight, and is considered to be more suitable for crushing and grinding problems, where the machines ordinarily are operated under constant volume conditions. It has the advantage that surface areas of different materials can be compared directly, even though their specific gravities may be unknown. The "specific surface" of a material, or the number of square centimeters of surface area per gram, is equal to 100S divided by the specific gravity. Particle diameters are expressed in microns, K being the diameter of the largest particle present and L the grind limit, or lower size limit of the particles formed directly by grinding. The value of K does not always coincide exactly with the diameters of the largest particles retained on the coarsest testing sieve, since the largest particles formed in crushing and grinding are often slabby, or have other irregular shapes. L has been chosen as 0.700 microns, or number 27.5 in the size number series, for reasons to be explained later. S is the total surface area of all particles larger than L microns in diameter. When a homogeneous comminution product is separated into fractions whose diameters bear a constant geometrical relationship p to each other, and the log per cent weight retained upon each size and passing the next larger size is plotted against the log diameter, a straight line results, which is called the distribution line, and which has a slope in called the distribution modulus. The distribution line can be extended to any desired limiting size, and the total surface area of all particles larger than that size can be calculated. The equation of the distributi0n line is [w = Cx" [I]] where w is the per cent weight retained on each successive sieve; x is the particle diameter; and C is the per cent weight retained on an opening of unit diameter.2 Theoretically, the distribution line can be extended to include infinitely small particles. When it is so extended, and the assumption is made that no fine particles are present other than those accounted for by the equation; the log per cent cumulative weight passing any series of sizes, plotted against the log diameter passed, will result in a straight line lying parallel to and above the plotted distribution line.

Jan 1, 1941

By R. Schumann

THE expression "unit process " comes up with increasing frequency in discussions among metallurgists and mineral engineers, especially among those concerned with training the next generation. The unit process approach characterizes a significant advance along the road from metallurgy as an empirical art to metallurgy as a branch of engineering. The purposes of this paper are to define and list the unit processes in specific terms, to indicate the scientific and engineering principles basic to all the unit processes, and finally to show how these ideas have been applied to a reorganization of instruction in chemical metallurgy. UNIT OPERATIONS AND UNIT PROCESSES Metals are extracted from ores and other raw materials by stepwise procedures. In general, each metallic element is extracted by a different procedure. For many of the metals there is a choice of several flowsheets. However, the procedures all have steps in common. In fact, the many different flowsheets are all made up of a relatively small number of steps which are combined in different groups and sequences. For example, crushing, screening, roasting, sintering, melting, and gaseous reduction are steps which each appear in the flowsheets for extracting the majority of the metals. The individual steps or flowsheet units can be designated as unit operations or unit processes. These terms are well established in the field of chemical engineering, as the American Institute of Chemical Engineers' definition of chemical engineering shows: " Chemical engineering is that branch of engineering concerned with the development and application of manufacturing processes in which chemical or certain physical changes of materials are involved. These processes may usually be resolved into a coordinated series of unit physical operations and unit chemical processes. The work of the chemical engineer is concerned primarily with the design, construction, and operation of equipment and plants in which these unit operations and processes are applied. Chemistry, physics, and mathematics are the underlying sciences of chemical engineering, and economics its guide in practice."1a In this definition, the distinction between unit operations and unit processes is that the unit operations are physical while the unit processes are chemical. Table I gives a list of the principal unit operations and unit processes of chemical engineering, taken from Shreve. lb Table 2 lists the principal unit operations and unit processes used for metal extraction. The division between unit operations and unit processes is similar to the chemical engineers' distinction and also corresponds approximately to the division of labor between mineral dressing and chemical metallurgy which has been customary in the past. Furthermore, it will be noted that in the proposed classification the unit processes primarily involve chemical reactions and/or changes in state of aggregation; the unit operations, primarily do not involve either bulk

Jan 1, 1948

By Roland D. Parks

CORUNDUM, little publicized as an industrial abrasive, has, in its small way, contributed greatly to the production of many specialized items vital to our war program and to our allies. Optical elements of the highest quality for range finders, bombsights, and scientific instruments; precision metal parts for torpedoes and airplane engines; quartz crystal plates for military radios; armorplate and malleable castings for tanks and guns; and eyeglasses for everyone; these are some of the products that corundum has helped to produce in the quantities needed and on time. Unlike metals and many other raw materials, corundum is not incorporated into any of these finished products. It is simply a grinding medium used to produce the desired finish or precision; an operating supply or tool, so to speak. With a Mohs' scale index of o, corundum ranks next to the diamond in hardness among the natural minerals and is superior to emery and garnet. The gem varieties of corundum, including the Oriental ruby and sapphire, are frequently more highly prized as jewels than the diamond. It is the intent of this paper to deal only with a description of the corundum industry, the administration of wartime control, and certain economic aspects as seen by the author. Several references are listed to assist anyone who wishes further information on the geological occurrence of the mineral. ORE PRODUCTION AND CONSUMPTION For the past two decades, South Africa has been the world's sole producer of corundum ore. A possible exception is Russia, where, it is understood, there was considerable production during the thirties for domestic consumption but for which statistics are lacking. The United States is the world's principal consumer of corundum ore; imports for the period 1934 through 1940 averaging 3000 short tons per year. The years 1935 and 1936 were close to the 5000-ton mark, and imports during 1941, the last prewar year for which statistics have been released, were approximately 6000 short tons. Again lacking statistics on Russia, the United Kingdom ranks second, but far below the United States in consumption of ore. Historically, corundum has been found in some 35 countries throughout the world, but the principal deposits are in South Africa, Canada, Madagascar, Russia and the United States. Deposits are generally small and subject to rapid exhaustion. Thus, the United States was the principal world producer for the period 1870 to 1900, when operations ceased except for two years during World War I. India was a producer of ore from 1898 through 1921, with peak output in 1916 through 1918. Canada came into production in 1901 with substantial output of ore and finished grain until 1914; the production thereafter was smaller until 1921. Madagascar has produced ore since 1910 but has had important output in only a few scattered years. South African production started in 1912,

Jan 1, 1945

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 H. L. James

This paper presents the results and analysis of field trials of various magnetic instruments over anomalies ranging from 20 to 5000 gammas of vertical intensity. The following instruments were used: Askania vertical magnetometer, Wolfson vertical magnetometer (model M-I), Hotchkiss Superdips (used both parallel to and normal to the magnetic meridian, with several settings of the "sigma" angle), Lake Superior dip needle, and the dipping circle for measurements of inclination. The change in inclination over the measured anomalies ranged up to 4"; this caused pronounced changes in sensitivity of the Hotchkiss Superdip oriented parallel to the magnetic meridian. The variable sensitivity not only gives apparent displacement of crests of anomalies, particularly at high sensitivities, but also makes the data difficult or impossible to use in preparation of iso-anomaly maps. This weakness in field performance of the Superdip is shown to be eliminated by orienting the instrument normal to the magnetic meridian and measuring vertical intensity only, which in the latitude of upper Michigan is equal to 97 pct of the total intensity. The dip needle is seen to be relatively ineffectual for location of anomalies of less than 400 gammas. Introduction The U.S- Geological Survey, in cooperation with the Geological Survey Division of Michigan Department of Conservation, has for the past three years been engaged in a restudy of the Iron River-Crystal Falls iron mining district of upper Michigan. The bedrock in a large part of this area is covered with glacial deposits as much as 500-ft thick, and, inasmuch as some of the rocks have moderate to high magnetic permeability, extensive magnetic mapping has been done to assist in unraveling the complicated structure of the area. Several types of instruments have been used, and the major purpose of this paper is to present comparative data on the field performances of some of these instruments so as to aid others who face similar problems elsewhere to evaluate and choose the instruments best suited for the work. The paper is directed primarily to geologists and engineers rather than to geophysicists, although some familiarity with the instruments is presumed. The geology of the area consists of a complexly folded series of weakly metamorphosed sedimentary rocks, including the iron formation, which rests on older greenstones. Although the iron formation itself is only locally magnetic, some of the beds stratigraphically above the iron formation are rather strongly so. By tracing these hanging wall magnetic anomalies valuable information is obtained from which the structure and distribution of the iron formation can be inferred. Critical anomalies range from 25 to 6000 gammas of vertical intensity. Many anomalies can be traced in part with the common dip needle, but detection of others requires more sensitive instruments.

Jan 1, 1949

By H. L. James

This paper presents the results and analysis of field trials of various magnetic instruments over anomalies ranging from 20 to 5000 gammas of vertical intensity. The following instruments were used: Askania vertical magnetometer, Wolfson vertical magnetometer (model M-I), Hotchkiss Superdips (used both parallel to and normal to the magnetic meridian, with several settings of the "sigma" angle), Lake Superior dip needle, and the dipping circle for measurements of inclination. The change in inclination over the measured anomalies ranged up to 4"; this caused pronounced changes in sensitivity of the Hotchkiss Superdip oriented parallel to the magnetic meridian. The variable sensitivity not only gives apparent displacement of crests of anomalies, particularly at high sensitivities, but also makes the data difficult or impossible to use in preparation of iso-anomaly maps. This weakness in field performance of the Superdip is shown to be eliminated by orienting the instrument normal to the magnetic meridian and measuring vertical intensity only, which in the latitude of upper Michigan is equal to 97 pct of the total intensity. The dip needle is seen to be relatively ineffectual for location of anomalies of less than 400 gammas. Introduction The U.S- Geological Survey, in cooperation with the Geological Survey Division of Michigan Department of Conservation, has for the past three years been engaged in a restudy of the Iron River-Crystal Falls iron mining district of upper Michigan. The bedrock in a large part of this area is covered with glacial deposits as much as 500-ft thick, and, inasmuch as some of the rocks have moderate to high magnetic permeability, extensive magnetic mapping has been done to assist in unraveling the complicated structure of the area. Several types of instruments have been used, and the major purpose of this paper is to present comparative data on the field performances of some of these instruments so as to aid others who face similar problems elsewhere to evaluate and choose the instruments best suited for the work. The paper is directed primarily to geologists and engineers rather than to geophysicists, although some familiarity with the instruments is presumed. The geology of the area consists of a complexly folded series of weakly metamorphosed sedimentary rocks, including the iron formation, which rests on older greenstones. Although the iron formation itself is only locally magnetic, some of the beds stratigraphically above the iron formation are rather strongly so. By tracing these hanging wall magnetic anomalies valuable information is obtained from which the structure and distribution of the iron formation can be inferred. Critical anomalies range from 25 to 6000 gammas of vertical intensity. Many anomalies can be traced in part with the common dip needle, but detection of others requires more sensitive instruments.

Jan 1, 1949

By W. I. Garms, J. L. Stevens

BECAUSE of the many conflicting opinions regarding the functioning of the ball load and the characteristics of ball wear in ball-mill grinding, the following resume of reports covering recent tests conducted at the Hayden plant of the Kennecott Copper Corporation is submitted with the view of pointing out certain salient features that should throw additional light on the subject. MILLS USED Cylindrical drum mills with trunnion feed and discharge were used. The discharge trunnion was I3 1/2 in. in diameter. Dimensions inside the lining were 6 ft. 6 in. in diameter and 9 ft. 6 in. long. The mills were Britannia-lined and nine lifter bars projected 2 in. from the lining. The mill speed was 16 2/3 r.p.m. Feed to the mill was 9 per cent on 10-mesh, 85 per cent on 100-mesh, 77 per cent solids. New balls measured 2 in. in diameter and the approximate weight of the ball load was 40,000 pounds. INITIAL TEST During a test that was being conducted to determine the relative economic value of standard cast balls vs. forged steel balls in the local grinding operation, certain observations were made in regard to the functioning of the various ball sizes and the characteristics of ball wear, which warranted a supplementary test for the purpose of confirming such observations. For the initial test, the necessity for developing a graduated load of the new forged balls before the test could be started was realized, but the time required to obtain a graduated load and the functioning of the various ball sizes was not clear. No advantage could be seen for starting out with a full load of forged balls, as this initial load, at the least, would have to be completely ground out and replaced by daily additions of balls before the graduation could be complete and a normal static condition of ball sizes reached. For a considerable period prior to exhaustion of this initial charge there would be an unusual quantity of worn balls of a certain size, which would not be typical of a normal charge and could influence the characteristics and functioning of the entire load. Therefore, it was decided to start by daily addition of the forged balls to a mill that contained a normal operating load of cast balls. After 88 days of operation the mill was shut down for inspection. By that time the load consisted of a mass of forged balls functioning around a large core of the residual material of the former cast-ball load. This core of cast slugs, locally referred to as "the kidney," was well defined from the forged-ball load.

Jan 1, 1946

By E. C. Houston, H. S. Rankin

Olivine is considered a valuable potential source of metallic magnesium in the chloride electrolytic process. Treatment of olivine with hydrochloric acid can be carried out under conditions that prevent the formation of gelatinous silicic acid, which would inhibit the reaction by forming a covering around the ore particles. It is our hypothesis that the formation of gelatinous silicic acid is avoided by the dehydrating action of the magnesium chloride, which takes up water to form a series of hydrates and leaves the silicic acid in granular condition. Leaching serves to separate the magnesium chloride from the silicic acid and unattacked ore, which can be treated with fresh acid in successive steps until extraction is essentially complete. The leach solution can be i purified by the addition of caustic magnesia and the precipitated impurities removed by decantation or filtration. The resulting magnesium chloride contains: Fe, less than 0.001 Per cent; Mn, 0.012 ; per cent; Ni, none. Chlorination† of olivine has two major defects: (1) a large part of the chlorine goes to form silicon and iron chlorides, (2) the anhydrous magnesium chloride is held by absorption in the finely divided silica. SupplY It is well known that olivine, a silicate of magnesium and iron, is present in large amounts in several localities in the United States. The largest deposits occur in the southeast and on the Pacific Coast.' The southeastern deposits were surveyed by Lewis2 in 1896 and by Hunter3 in the period 1933-1940 It is estimated that high-grade olivine, conveniently located with regard to transportation and power, is present in excess of 230 million tons above local drainage level in western North Carolina and north Georgia. Previous Technical Work In the past few years, olivine has attracted considerable attention in the refractory field. In the chemical processing industry, however, it has long been thought axiomatic that the cost of processing silicates is an economic barrier to their utilization, especially where more reactive minerals, such as carbonates, oxides or salts, are available. This attitude is not entirely justified in connection with olivine. unlike most silicates, olivine is readily attacked by acids, chlorine and other reagents without resorting to fusion to break down the silicate structure. Olivine has been suggested as a raw material for making epsom salt by roasting with pyrites.4 Other processes include acid treatment6 and digestion with calcium chloride.6 Recently a small plant was built near Webster, N. C., for making epsom salt from olivine by treatment with sulphuric acid. This plant is now in commercial operation, producing approximately two tons per day. Olivine is also receiving attention from the fertilizer industry as an inexpensive source of soluble magnesium.

Jan 1, 1942

By H. S. Rankin, E. C. Houston

Olivine is considered a valuable potential source of metallic magnesium in the chloride electrolytic process. Treatment of olivine with hydrochloric acid can be carried out under conditions that prevent the formation of gelatinous silicic acid, which would inhibit the reaction by forming a covering around the ore particles. It is our hypothesis that the formation of gelatinous silicic acid is avoided by the dehydrating action of the magnesium chloride, which takes up water to form a series of hydrates and leaves the silicic acid in granular condition. Leaching serves to separate the magnesium chloride from the silicic acid and unattacked ore, which can be treated with fresh acid in successive steps until extraction is essentially complete. The leach solution can be i purified by the addition of caustic magnesia and the precipitated impurities removed by decantation or filtration. The resulting magnesium chloride contains: Fe, less than 0.001 Per cent; Mn, 0.012 ; per cent; Ni, none. Chlorination† of olivine has two major defects: (1) a large part of the chlorine goes to form silicon and iron chlorides, (2) the anhydrous magnesium chloride is held by absorption in the finely divided silica. SupplY It is well known that olivine, a silicate of magnesium and iron, is present in large amounts in several localities in the United States. The largest deposits occur in the southeast and on the Pacific Coast.' The southeastern deposits were surveyed by Lewis2 in 1896 and by Hunter3 in the period 1933-1940 It is estimated that high-grade olivine, conveniently located with regard to transportation and power, is present in excess of 230 million tons above local drainage level in western North Carolina and north Georgia. Previous Technical Work In the past few years, olivine has attracted considerable attention in the refractory field. In the chemical processing industry, however, it has long been thought axiomatic that the cost of processing silicates is an economic barrier to their utilization, especially where more reactive minerals, such as carbonates, oxides or salts, are available. This attitude is not entirely justified in connection with olivine. unlike most silicates, olivine is readily attacked by acids, chlorine and other reagents without resorting to fusion to break down the silicate structure. Olivine has been suggested as a raw material for making epsom salt by roasting with pyrites.4 Other processes include acid treatment6 and digestion with calcium chloride.6 Recently a small plant was built near Webster, N. C., for making epsom salt from olivine by treatment with sulphuric acid. This plant is now in commercial operation, producing approximately two tons per day. Olivine is also receiving attention from the fertilizer industry as an inexpensive source of soluble magnesium.

Jan 1, 1942

By H. S. Rankin, E. C. Houston

OLIVINE is considered a valuable potential source of metallic magnesium in the chloride electrolytic process. Treatment of olivine with hydrochloric acid can be carried out under conditions that prevent the formation of gelatinous silicic acid, which would inhibit the reaction by forming a covering around the ore particles. It is our hypothesis that the formation of gelatinous silicic acid is avoided by the dehydrating action of the magnesium chloride, which takes up water to form a series of hydrates and leaves the silicic acid in granular condition. Leaching serves to separate the magnesium chloride from the silicic acid and unattacked ore, which can be treated with fresh acid in successive steps until extraction is essentially complete. The leach solution can be purified by the addition of caustic magnesia and the precipitated impurities removed by decantation or filtration. The resulting magnesium chloride contains: Fe, less than 0.001 per cent; Mn, 0.012 per cent; Ni, none. Chlorinationt of olivine has two major defects: (I) a large part of the chlorine goes to form silicon and iron chlorides, (2) the anhydrous magnesium chloride is held by absorption in the finely divided silica. SUPPLY It is well known that olivine, a silicate of magnesium and iron, is present in large amounts in several localities in the United States. The largest deposits occur in the southeast and on the Pacific Coast.1 The southeastern deposits were surveyed by Lewis2 in 1896 and by Hunter3 in the period 1933-1940. It is estimated that high-grade olivine, conveniently located with regard to transportation and power, is present in excess of 230 million tons above local drainage level in western North Carolina and north Georgia. PREVIOUS TECHNICAL WORK In the past few years, olivine has attracted considerable attention in the refractory field. In the chemical processing industry, however, it has long been thought axiomatic that the cost of processing silicates is an economic barrier to their utilization, especially where more reactive minerals, such as carbonates, oxides or salts, are available. This attitude is not entirely justified in connection with olivine. Unlike most silicates, olivine is readily attacked by acids, chlorine and other reagents without resorting to fusion to break down the silicate structure. Olivine has been suggested as a raw material for making epsom salt by roasting with pyrites.4 Other processes include acid treatments and digestion with calcium chloride.6 Recently a small plant was built near Webster, N. C., for making epsom salt from olivine by treatment with sulphuric acid. This plant is now in commercial operation, producing approximately two tons per day. Olivine is also receiving attention from the fertilizer industry as an inexpensive source of soluble magnesium.

Jan 1, 1942