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THE composition and quality of finished steel depend upon selection and proportioning of the raw materials of the charge as well as upon control of furnace practice. This chapter deals only with the raw materials of the basic open-hearth process that are important in determining the composition of the steel or slag. They are the metallic charge, oxygen-bearing materials, fluxes, alloying and deoxidizing additions, and certain refractory materials used for maintenance of bottoms. Other refractories, which may affect the slag composition, are discussed in Chapter 3. Wide variations are possible in the type and composition of charged materials but certain limiting relations among the elements of the charge must be observed. Since the process consists essentially of refining by the oxidation of undesired dements, a balance must be established between the sources of oxygen and the elements in the charge that are subject to oxidation (see Chapters 2 and 7). For example, if it is desired to use a high ratio of blast-furnace hot metal to scrap, it is necessary to add an oxygen-bearing material such as ore or mill scale to eliminate the excess carbon and silicon that are present in the hot metal. An example of the opposite extreme is the use of a metallic charge composed entirely of steel scrap. With this type of charge, it is common practice to substitute burnt lime for limestone as a flux and to charge some carbonaceous material such as coke to avoid an excess of oxygen in relation to the elements of the charge that are subject to oxidation. Elements such as copper and nickel, which are not oxidized or eliminated by, any other reaction, may be introduced into the charge only to the extent to which they are permissible in the finished steel. An example of adjustment of the charge for elements of this type is found in the use of steel scrap high in copper. In this case, metallic components of the charge other than the scrap should be low in copper, or a sufficiently high ratio of pig iron to scrap should be charged to dilute the copper from the

Jan 1, 1951

By Herbert R. Mosley, Paul M. Tyler

STRATEGICALLY situated in almost the heart of the leading fertilizer- consuming area of the United States, Tennessee long has ranked second only to Florida as a phosphate-producing state. Since 1932 its share of the national output of phosphate rock has increased steadily, and in 1937 its production mounted to an all-time record. More significant even than the increase in tonnage are the forward strides in technology. The Tennessee Valley Authority's research program has led to quasicommercial operations using hydroelectric power to manufacture concentrated phosphatic fertilizer that is used to further the farmer education program designed to streamline the fertilizer business and halt the appalling waste of farm land by soil erosion. Even more stimulating to chemically minded imaginations is the production of elemental phosphorus by a private company that not only has succeeded in extracting it from the phosphate rock in electric furnaces but actually has contrived to capture it and to transport it safely in tank cars. New values have been created for low-grade phosphate deposits, and the economic life of reserves has been lengthened while the waste of former years goes back into the mills for recovery of its values by modernized methods. Tennessee's phosphate-mining industry dates from the discovery of blue rock in-lewis County in December 1893. Its known reserves are of the order of 101,500,000 tons, which compares with the production of 825,099 tons in 1937; that is, 21 per cent of the phosphate-rock output of the whole nation. The total output reported from 1894 until July 1, 1938, was approximately 19,000,000 tons. Official estimates of reserves are overly conservative and evidence submitted before a joint Congressional committee in November 1938 places "probable" reserves at more than 6,000,000,000 tons.

Jan 1, 1939

By S. F. Emmons

IT was said by many who discussed Professor Posepny's admirable paper on the " Genesis of Ore-Deposits," read at the Chicago meeting of the Institute, in 1893, that its most valuable feature was the clear distinction which it drew between the influence upon ore-deposits of the "vadose " circulation of waters descending directly from the surface, and that of the deep underground circulation of waters generally coming from the depths, and assumed by the author to be ascending through more or less open spaces under the influence of heat. A little later the effect of the oxidizing action of the vadose circulation upon ore-deposits was ably and exhaustively treated by Prof. R. A. F. Penrose, in a paper on " The Superficial Alteration of Ore-Deposits "f-the only one, so far as I know, which has been exclusively devoted to this important subject. My own first detailed study of ore-deposits was made at Leadville, in 1880, at a time when almost the only minerals visible in those deposits were in oxidized forms. That this form was the result of the alteration of earlier sulphides by surface-waters had to be proved at the time by induction or analogy, the general correctness of which was, however, abundantly confirmed by subsequent developments. Thus I was early impressed with the importance of distinguishing, in the study of an ore-deposit, the alteration-products, resulting from the action of oxidizing waters descending from the present surface, from the earlier-formed sulphides; and, assuming that the latter were primary or original, I called the former secondary. I also went so far as to say$ with regard to oxidized ores passing into sulphides in depth "So generally is this accepted as a rule in ore-deposits that it would require special demonstration to prove beyond a doubt that the native metals or their

Jan 1, 1902

By W. H. Schacht

In the Lake Superior District, the air indoors must be heated continuously during eight months of the year and occasionally during the remaining months. Incident with mining in this district, therefor?, there is need for heating many of the buildings connected with these operations. In addition to the mine buildings, that is, shops, engine houses, offices, change houses, etc., such public buildings as schools, library, and theater, when close to the mines, are often supplied from the mine heating mains. At the Copper Range Company's mines, Champion, Trimountain and Baltic, the heating surface thus supplied from the mine mains is over 50,000 sq. ft. (4645 sq. m.) which requires a steam consumption, at times, of 18,000 Ib. (8165 kg.) per hour, or the equivalent of a rate of ovcr 50 tons of coal per day (were live steam used). This figure is based on a consumption of 1/3 Ib. per sq. ft. of heating surface during the coldest weather, and provided the system is not wasting steam by blowing it to the atmosphere or into the return line on account of leaky traps, which so often is the case. Under the latter conditions, steam consumptions of three to four times the above rate are not uncommon. This shows that the cost of heating is of enough importance to he given serious consideration, especially at this time of rising prices of fuel. The power and heating value of exhaust steam arc appreciated by most engineers, and its application for such purposes is general. At our stamp mills, the exhaust from the stamps is used to operate low-pressure turbines, thus reducing the former water rate per horsepower developed by more than 50 per cent. At the above-mentioned mines, electric motors have replaced the many small steam engines, so that this supply of exhaust steam has been practically eliminated. The larger engines are compound, triple, or quadruple condensing. The hoists, however, in all cases are simple and non-condensing and of two sizes, namely, 24 by 60 in. and 32 by 72 in. (61 by 152 cm. and 81 by 183 cm.). These hoists now offer the only available supply of exhaust steam; but as this flow is intermittent and varies from extreme violence to zero, the steam so discharged cannot be

Jan 1, 1922

By P. D. Gorsuch, I. R. Kramer, D. L. Newhouse

Although many methods have been suggested for the calculation of tensile strength and yield point from chemical composition, their usefulness has been limited to a particular cooling rate or section size. Further limitations have been imposed by failure to take into account many of the alloying elements that exert a considerable influence on the tensile strength or yield point. These systems, nevertheless, have filled an important need in many instances. The value of a system for the calculation of the tensile properties from the chemical composition and cooling rate is that it permits the prediction of the effect of alloying elements and heat-treatment on the mechanical properties, so that more efficient use of alloying elements may be made. Furthermore, it aids in the choice of steel for a given application aid tends to decrease the number of steels that otherwise would have to be tested. It is the purpose of this work to present a method of calculating tensile strength and yield point from the chemical composition and to suggest a method of correlating the tensile-strength and yield-point factors and cooling rate. Steelmakers have been interested for many years in the calculation of the tensile strength of hot-rolled steels. Quest and Washburn' summarize several of the attempts that have been made to devise formulas. They show the inadequacy of each of these formulas and present one of their own. It is apparent from their work that a simple additive equation of the type TS = A + BX + Cy + DZ + . . . , where A, B, C, D, etc. are experimentally determined constants and x, y, z, etc., are the percentages of alloying elements present in the steel, is not adequate to analyze fully the situation encountered in the calculation of tensile strength. For example, it was found that the difference between the calculated and observed values became progressively greater as the carbon and manganese contents were increased. Therefore, the effect of manganese was given as a function of the carbon content. Grossmann, in his work on the harden-ability of quenched steels, and Walter, in his method of calculation of tensile strength of normalized steels, present two cases in which multiplying factors were successfully used to express the combined effect of alloying elements. The factors in both cases were obtained from the fractional increase in hardenability or tensile strength with increase of alloy content. Yield point often is more important in design than tensile strength. For quenched and tempered steels a linear correlation exists between yield 2nd tensile strength.4 This is not true, however, for normalized

Jan 1, 1948

By T. A. Wright

The sampling of waste materials containing copper, lead and tin has taken on a new significance within recent years, and is of increasing importance, on account of the entry of some of the copper refineries into this field and the tendency towards consolidations among the smelters. In the past, such material was sold on the basis either of a rough or grat) sample or of casual inspection of the lot. The two principal sources of this waste are the processes of fabrication and the scrapping of automobile, electrical, plumbing, railroad and other equipment. In both cases rnuch material can bc sorted, salvaged and sold by classification and grade to be melted "as is" or with the addition of new or virgin metal. The increasing care in classifying exercised in the large manufacturing plants tends to incrcase the proportion of this usable scrap; on the contrary, the increasing use of more complex and special non-ferrous alloys tends to makc sorting and grading more difficnlt in turnings, borings, clippings, etc., and conseqllcntly is making sampling of more moment. In tin, lead, alumiinum, and zinc furnace by-products such as ashes, drosses, skimmings, etc., the trade practice of evaluation has not varied much. For instance, tin drosscs, battery lcad, and aluminunl skimmings are ordinarily sold on what is called "metallic button" or "metallic recovery" or "metallic yield." Coppcr and Icad wastcl, howcvcr, is being sold more and more on actual copper and lead contents bascd on sarrlple and chemical analysts. This paper will be dcvotctl chiefly to the sampling of niaterials suitablc only for refining and recovery of one or more of the metals present. The methods described are often bascd on thc fact that but one, metal, such as copper, is to be paid for. The loss of volatile constituents in melting does not appreciably affect thc final copper result, as the "after-melting" assay can be readily calculated to the "bcfore-nltltingl' basis, but if smelter efficiency continues to increase, so that in tiltie zinc, for instance, may be rccovrred on a paying basis, thc method of sampling dirty brass, for example, will have to bc changed also. As a matter of fact, we may cxpect that improved refining proresses will make possible the partial reeovrry of lcad and tin which are now lost

By H. P. Moore, R. W. Fenn, Harold Margolin, W. R. Hibbard

DEFORMATION lines, also called etch markings or strain markings, are noneffaceable lines developed in individual grains by etching a metal specimen which has been cold worked sufficiently to cause atomic non-conformity or slight orientation differences within the grains. Etching occurs more rapidly at these lines of high chemical reactivity to produce a result similar to that revealing grain boundaries.1 Wider etching effects forming bands have been found. They are believed to be bands of deformation lines which form areas of measurably different orientation from the crystal matrix. The crystallite rotations causing these bands have been shown by Barrette to contribute to deformation textures. Although deformation lines have been observed in many metals, the amount of deformation required for their appearance has been established only in general terms. Mathewson and Phillips3 observed the first appearance of deformation lines in cold-rolled alpha brass at about 20 pct reduction in thickness using the standard ammonium hydroxide hydrogen peroxide etchant. Price and Davidson4 noted deformation lines in common high brass after 26.5 pct reduction by cold rolling using the same etchant. Johnson' observed dark thick forklike lines in 99.99 pct pure copper reduced 31.8 pct. Adcock6 observed deformation lines in 80-20 copper-nickel alloy rolled 50 pct. Samans7 found no deformation lines in alpha brass single crystals cold rolled 9.5 pct but they did appear after 25 pct reduction using ammonium hydroxide and hydrogen peroxide etchant. Barrett and Levenson8 observed deformation bands in drawn polycrystalline iron at very small reductions in area and noted that their initial appearance perhaps depends on grain size and other conditions. They reported deformation bands in a single crystal of iron reduced 6 pct by drawing. Brick9 noted that deformation lines in 70-30 brass apparently associated with {111} planes appeared after reductions of from 20-50 pct by cold rolling. Brick and Williamson10 noted that in single crystals of 70-30 alpha brass "as in polycrystalline brass, no deformation markings appeared until reductions exceeded 20 pct." Cook and Richards11 reported that in copper cold rolled less than about 50 pct few strain markings were apparent but for higher. reductions many strain markings appeared transverse to the rolled direction. In a review article Brick and Phillips12 noted that previous studies had not shown deformation lines in cold rolled alpha brass

Jan 1, 1948

By J. A. Ede

The property of the Spring Valley Coal Company, situated in Bureau county, Ill., comprises something more than 30,000 acres of coal-lands, on which have been opened four mines, designated as Nos. 1, 2, 3 and 4. Figs. 1, 2, 3 and 4 are plans of the first three; and Fig. 7 is a view of the surface-plant at No. 4, the workings of which it is not necessary to illustrate, as this mine has been practically merged in No. 2. No. 4 shaft is only 500 feet from No. 2, and both are ventilated by the same fan, and are in the same circle of air-supply. In speaking of No. 2, we now include No. 4. The system pursued in all the mines is " long-wall advancing," and the shafts are all vertical. The seam worked is locally and commercially known, in the Illinois series, as No. 3; but its position in the geological series is that of No. 2. It averages in thickness about 42 inches, arid has no partings, but mines in rectangular lumps, which stand a large amount of handling before breaking. An analysis made from Colliery No. 1 gave the following : Per cent. Moisture,.......... 1.45 Volatile combustible matter,.47.27 Fixed carbon,.........41.97 Sulphur,.........2.46 Ash,....... .. .. .. 6.85 Plate 6 shows a photographic view of this seam. The staff seen in the view is 37 inches long. The table on page 188, recorded in my office, which I presume to be correct, may be of interest. The bottom is fire-clay, varying in thickness from 6 to 24 inches. It affords what is considered good mining-ground. The roof immediately above the coal is a dark shale, lying in small bands, from 4 to 9 inches in thickness. Between the

Jan 1, 1900

By Charles H. Jacoby

In 1774 a Swedish chemist, C. W. Schule, first recognized manganese as an element. That same year Schule's associate, J. G. Gahn, isolated the element manganese for the first time. In 1856 the Bessemer process of steelmaking gave birth to the economic importance of manganese. Later, in 1882, Robert Hadfield discovered high manganese steels. Although the primary use of manganese is in the ferroalloy industry, two additional important uses for manganese are making chemicals and dry cell batteries. Manganese is also vital to plant and animal life. Various chemical compounds of manganese are used in fertilizers, feeds, glass manufacture, paints, varnishes, and for numerous medicinal and chemical purposes. For the study of industrial minerals and rocks, only the chemical and battery grade material is of- concern, but for the sake of comparison, metallurgical aspects are included in this presentation. Although currently the world's largest consumer of manganese, the United States is producing only minor amounts of ore at the present time. This is due primarily to the fact that although huge deposits of manganese occur within our borders, all are of such low grade as to be economically unfeasible to mine. For many years various government agencies and segments of private industry have devoted sizable sums of money and time in an attempt to upgrade ores from the various deposits, and also in an attempt to recover manganese from blast furnace slags. In view of current world prices, and the quantity of high grade material available, there is little likelihood that any of these approaches will be found to be economically feasible in the near future. Geology and Mineralogy Mineralogy There are over one hundred minerals that contain manganese. These minerals vary from those with compositions that are predominantly manganese to those having only minor percentages. [Chemical Mineral Composition % Mn Hausmannite Mn304 72 Polianite MnO2, 63.1 Pyrolusite MnO24 60-63 Cryptomelane KR8O16R (R=Mn) Variable PsilomelaneBa Mn Mn8O16 (OH).45-60 CoronaditePb R8O16R (R=Mn) Variable Hollandite Ba R8O16R (R=Mn) Variable Manganite Mn2O3•H20 62 Braunite 3 Mn2O3•MnSiO3 62 Tephroite 2 MnO•SiO2 54.3 Rhodochrosite MnCO3 47 Rhodonite MnSiO3 42 Spessartite 3 MnO•AI2O3•3SIO2 33.3 WadHydrous Mn OxidesVariable Franklinite(Fe Mn Zn)O(Fe Mn)sO3 Variable Asbolan Cobaltiferous wad Variable AlabanditeMnS63.14] Geology From a geological standpoint most manganese deposits are complex. In general, it can be said that all primary deposits of manganese are carbonates or silicates. The most productive and profitable have been those of sedimentary origin and residual concentrations. Examples of these residual types of deposits are associated with the metamorphosed lodes of Madhya, Pradesh, India, and the lateritic deposits of Orissa and Bihar, India; nodules in the residual clays of the Philippine Islands, US southern Appalachians and Arkansas, Ghana, and Brazil. Sedimentary manganese deposits are best exemplified by the Nikopol district of Russia and the Tchiatouri area of Georgia, USSR. Hydrothermal replacements are characterized by the rhodochrosite deposits of Butte and Phillipsburg, MT. In general, the hydrothermal type deposit has not resulted in any large tonnages being produced, but may have given

Jan 1, 1983

By Frank H. Riddle, Wilfrid R. Foster

GENERAL treatment of the various minerals of importance in refractories appears in the chapter entitled "Refractories" elsewhere in this volume. The present chapter is restricted to a discussion of minerals of the sillimanite group and brings up to date the excellent information contributed by Prof. Paul F. Kerr to the first edition (1937). Since the appearance of that edition, the status of the group has changed some- what. Kyanite remains the preferred source material for mullite refractories but total consumption of kyanite has increased considerably.85 The exigencies of World War II forced an increased dependence on domestic sources and led to an intensification of the search for higher-grade deposits of kyanite and allied minerals. The first discovery of massive kyanite similar to that of India has been reported from Georgia.37 British East Africa has joined India as a substantial supplier of our imported kyanite, but that from India continues to hold preference.85 During World War II, prices of both domestic and foreign grades reached peaks unparalleled since the earliest years of the use of kyanite and as yet have shown no tendency to return to prewar levels. Topaz, by virtue of the deposit outlined in South Carolina, merits inclusion in the group.20,36,95 Large andalusite deposits, which threaten to rival our one large domestic occurrence, have been found in Russia.69,88 Sillimanite has not yet attained an important position among these useful minerals because of the lack of accessible deposits of high-quality material in adequate supply.37,50,58 Tests by the Bureau of Mines have indicated the possibilities of economically beneficiating low-grade sillimanite and kyanite.105.106,140 Government, university, and industrial

Jan 1, 1949

By G. Vaux, M. L. Fuller

AN apparatus and procedure for the determination by X-ray reflection of preferred orientation of crystals in rolled metal with the Geiger counter X-ray spectrometer was described by Schulz.' This is an excellent procedure and we have used it continually for several years. In our use of the procedure, two modifications have been made and used during most of this period. One of these provides for automatic scanning and recording of the reflections, and the other makes possible the application of the procedure to coarse-grained specimens and permits measurement of almost all orientations without resort to the transmission technique. The automatic scanning and recording are accomplished by a motor drive of the inner ring of the Schulz apparatus (see R, in Fig. 2 of his paper and R2 in Fig. 1 of this note) in synchronism with the chart recorder of the North American Philips 90" X-ray spectrometer. A rate of 10" per min is used. A scan of 180" is obtained corresponding to poles on the stereographic projection whose locus is a great circle. The modification for coarse-grained material is accomplished by allowing a larger area of the specimen to contribute to the X-ray diffraction. In the Schulz apparatus the incident X-ray beam is confined by a slit system to rays in the plane of the spectrometer. Schulz demonstrated that this restriction of the X-ray beam permits a survey of the X-ray reflections without correction up to about 80" on either side of that specimen position in which the specimen is perpendicular to the plane of the spectrometer. This is the angle + of rotation of the inner ring R2. One of these slits is horizontal and extends across the X-ray source side of the specimen. In the modification this slit is removed, thus permitting greater divergence in the X-ray beam and the irradiation of a larger area of the specimen surface. Fig. 1 shows the apparatus with the motor drive and with the slit removed. Discontinuities in the recorded X-ray intensity plot due to the few participating crystals in coarse-grained metal are much lessened. The increased divergence does not cause reflections from other crystal planes to enter the Geiger counter slit. An important advantage of the original Schulz scheme is thus lost and a system for correction is required. To do this, a compact of atomized copper powder was prepared and tested by the original Schulz method for the absence of preferred orientation. The horizontal slit was then removed and a curve recorded showing the variation of intensity with angle +. In our arrangement the intensity was uniform within the range + equals ±30°. Beyond this the intensity fell off rapidly reaching zero at ±90°. The curve thus produced is then used to correct measurements made on preferred orientation specimens. In practice this is accomplished by constructing from this calibration curve a family of curves which, as a transparency, can be superimposed on the recorder chart to read corrected intensity directly. Not only does this method permit the handling of coarse-grained material but it also makes possible the plotting of intensities almost to the circumference of the stereographic pole figure projection. Thus, nearly the entire pole figure can be plotted without the necessity of using the transmission technique. Moreover, intensities are much greater, an advantage when surveying crystal planes of poor reflecting power.

Jan 1, 1954

By R. J. Grace

Primarily, this report presents the results of direct efficiency tests which were conducted on the 200-hp Coal-Pak, hot water generator, No. 3 unit, at the Otterbein College heating plant in Westerville, Ohio. Also included is a comparison of fuel consumption of the old plant with that of the new plant, a comparison of efficiencies obtained by the indirect method on a 300-hp Coal-Pak, and the cost of gas vs coal to show the savings effected by the latter. Tests were conducted with ten different bituminous coals selected by Mr. S. A. Frye, business manager at Otterbein College. The coals, of ten different suppliers, from four different states and eight different seams, represented competitive products economically available to the heating plant. The tests were conducted by the usual plant personnel which consisted of the plant superintendent and two assistants. No outside supervision of any kind was given during the tests. The tests were made from Dec. 13, 1960, through Mar. 4, 1961. During this period, 300.03 tons of coal were burned in the No. 3 unit. This tonnage represented 25.5 pct of the total coal requirements for the 1960-61 season. Operation during the period was typical for the comfort heat load which the plant supplies. Of the 78.12 operating days, the boiler was on bank or holdfire 14.31 days, or 18.32 pct of the time. The length of individual bank periods varied from 2 hr to three days. Run periods varied from about 2 hr to 7.26 days. DESCRIPTION OF PLANT AND HEATING EQUIPMENT The new Otterbein College heating plant, completed in the summer of 1957, is located in a 50x50 ft boiler room on the lower level of a combination maintenance building and heating plant. The building is situated away from the main college complex on a hillside, which allows for on-grade delivery of coal to the three bunkers. The bunkers are located directly above and connected with the individual stoker hoppers. Fig. 1 shows an in-plant view of the Coal-Pak installations. The No. 3, hot water, unit is at the extreme right. The heating plant consists of three 200-hp Coal-Paks. Unit No. 1 is operated at 4 psi and carries the steam heating load of 14,000 sq ft EDR (steam) installed in two buildings. Provision has been made to convert these buildings to hot water heating at some future date. Since the unit under maximum load conditions operates only at about 50 pct steaming capacity, a heat exchanger was installed to convert steam to hot water. Thus, during light loads in mild weather the unit can be employed more efficiently to supply both steam and hot water and eliminate the need for operating either of the two hot water units. Units No. 2 and No. 3 serve a hot water heating circuit for a large group of 21 buildings of the College. These boilers deliver hot water at temperatures up to 200°F to the various buildings through distribution lines in tunnels. The present calculated maximum heat loss for the College is 15.195 million Btu per hr. The Coal-Paks have individual design capacities of 6.700 million Btu per hr. Table I lists the design date for the Coal-Paks. The No. 3 unit was chosen as the test unit, primarily because of its bunker location at the far end of the delivery ramp. Because of this location any excess coal above bunker capacity could be conveniently stored and isolated from the adjoining bunkers. Each bunker has a capacity of 30 to 35 tons of coal. The No. 2 and No. 3 hot water generators are equipped with automatic controls which maintain the

Jan 1, 1962

By Thomas MacFarlane

I. INTRODUCTION. AMONG the industrial enterprises which have, from time to time, been undertaken in our Dominion, few have been more uniformly unsuccessful than those which have had for their object the development of our mineral resources. These resources have not been regarded as insignificant. On the contrary, it is supposed that we possess in our ore deposits something more than mere points of mineralogical interest. Some people are enthusiastic enough to believe that our mineral wealth will yet occasion the establishment in our backwoods of happy and industrious communities, causing, in fact, our wilderness to blossom as the rose. These enthusiasts do not shut their eyes to the serious obstacles which at every stage interfere with the carrying out of mining enterprises in this country, and which tempt one to believe that no such enterprise can ever be conducted to a desirable end, but they entertain the conviction that as our capitalists, miners, and technologists reach the years of discretion, and handle our mines in an economical, vigorous, and judicious manner, and as our statesmen become alive to the necessity of fostering, without extremely protecting, our metallurgical industries, mines and furnaces will gradually prosper, and so develop as to become a tower of strength to our agricultural, manufacturing, and mercantile interests. The fact that our past experience does not generally justify such glowing anticipations makes one all the more anxious to put on record the history of a successful mine, such as the Silver Islet has, on the whole, been. My connection with its discovery and early development was a very intimate one, and I propose in this paper to sketch its history and character, and sum up the amount of silver it has so far yielded. An additional reason for the appearance of this paper is that the Transactions of the Institute contain only a few references to the Silver Islet Mine. Although this mine is reported successful, we have, of course, no guarantee that it will not fall a victim to the same influences which have

Jan 1, 1880

THE. extraordinary volume of work done in this period, and the multiplicity of subject matter, make a year-by-year historical account undesirable, if the account is not to be an assembly of unrelated fragments. We shall, instead, undertake to narrate the development in this period of each of the branches of the subject separately, hoping that their interrelations will be self-evident. There is a certain arbitrariness in the selection of subject matter in the following sections. The development of important engineering alloys-for example, high-speed steel-is disregarded, for it is the primary purpose of this account to relate the advances in ideas, the growth of the science of metals; other historical accounts relate these parallel advances. Nor are advances in techniques stressed, though occasionally the most important are noted; nor is the progress described in allied fields such as welding, cutting, etc.; for though these developments have very frequently made possible the advances herein related, they are far too numerous to recount in anything short of a ponderous volume. There is a more serious arbitrariness, however; it is not an easy matter to draw the boundaries of physical metallurgy, and some contiguous subjects have been omitted that perhaps should have been included, such as, for example, corrosion, gases in metals, the magnetic behavior of metals and alloys, and certain other fields in the physics of metals. REACTIONS IN ALLOYS--DIFFUSION Many of the reactions occurring in alloys proceed by the operation of the process of diffusion in the solid state: the annealing of mixed powders to form alloys, the homogenization of castings or forgings, the freezing of alloys, the treatment of clad metals, the loss

Jan 1, 1948

By Stephen Zorn

INTRODUCTION The process of financing mining projects in developing countries has changed greatly in the past 15 years. New methods of financing, notably the use of syndicated Eurocurrency project loans, have appeared, and direct equity financing by transnational mining corporations has become less significant. These changes are of particular importance to developing countries which have many mineral deposits still awaiting development, or even discovery. If major new mines are to be financed, host governments will need to obtain more sophisticated information than has hitherto been widely available as to the various sources of finance currently available and as to possibilities for innovative approaches to financing, such as the combination of several different kinds of financing in a single package. This paper reviews the major sources of mining finance potentially available to developing countries and highlights those problems in obtaining adequate financing that developing country producers have begun to experience in the last few years and that are likely to persist through the 1980s. Section I surveys the major types of mining finance; section II reviews specific financing problems, including (a) the withdrawal of the transnational corporations from developing countries, (b) inflation and the size of new projects; (c) developing country indebtedness, and (d) competition among projects in different countries. SOURCES OF DEVELOPING COUNTRY MINING CAPITAL1/ There is a wide range of financing mechanisms which are potentially available to developing countries with economically viable mining projects., Moreover, these financing mechanisms have not been fully exploited by developing countries, and more aggressive pursuit of financing by the governments of these countries may well reveal greater possibilities in respect of any particular project than may initially have appeared. However, virtually all the funds available from these sources are available only to projects which meet the standards of viability acceptable to lenders and others in the business community. If a project does not, for example, promise to generate a discounted cash flow rate of return of at least 15 per cent on total funds employed, or if it does not appear likely to generate sufficient cash flow in the early years of production to cover debt service requirements with a comfortable margin in reserve, most of the sources of financing will not be available. Only where a government has its own financial surplus (as in the case, for example, of the industrialization program of the Saudi Arabian government) can it effectively undertake projects which do not satisfy the definition of economic viability that is accepted at any given time by the worldwide financial community. Internal Sources In Developing Countries Internal financing capacity in developing countries is restricted to a relatively small number of countries - typically those large enough to support a well-rounded industrial sector, in which mining is only one of a number of dynamic industries. While there are large mining companies in certain other countries, the ability of such companies to finance new projects (or even, in some cases, to generate the cash necessary to maintain existing levels of production) is highly problematical. Within developing countries, the possible sources of internally-generated mining finance are the following: (1) state-owned enterprises; (2) private capital; (3) the banking system, and in particular those financing agencies that have a special involvement with the mining sector; and (4) direct budgetary appropriations.

Jan 1, 1985

By H. J. R. Way

The work to be described was undertaken at various periods from 1937 to 1939 on the Busia gold field, in the eastern province of Uganda. It was decided to examine the possibility of reef prospection by the resistivity method, for it was not known how far the usually disintegrated nature of most reefs in the ubiquitous laterite near the surface would obscure indications obtained by resistivity traverses. The work at the commencement was therefore largely experimental, but the results obtained thereby were satisfactory, and a survey was started at the Government closed area at Amonikakine. With the limited time and resources at the writer's disposal, it was not possible to complete the survey to his satisfaction or to follow up exhaustively all the geophysical indications, but some of the results of the experimental work and the survey were of sufficient interest to be worth recording; in particular the relation between the width of reef, electrode separation and shape of the curve, and the interference effect of constant separation curves over zones of float are significant and useful. Three new veins were located, but only one contained sufficient gold to warrant detailed prospection. This was called the Geophysical reef, and was uncovered over a strike distance of 1140 ft., and there are indications that it extends over a distance of 1990 ft. These results and the recom- mendations consequent therefrom were embodied in a special report to the Uganda Geological Survey. History OF the Field The Busia field is in the southeastern corner of Uganda near the Kenya-Uganda border, and is about 17 miles north of the northeastern corner of Lake Victoria. Gold was first discovered in the area in the stream beds by Davies1,2 in 1932. Subsequently numerous small alluvial claims were worked by prospectors and the area was prospected for reef by a company for periods varying from three to nine months, but was finally abandoned, as the results were considered unfavorable. Further prospecting by the Geological Survey in 1935-1936 under Davies8 and later under the writer4 uncovered three reefs with sufficient gold values to be of economic interest. These were finally taken over by a company known as Borderland Syndicate, which still owns the area, and from September 1937 to the end of 1941 about 13,000 oz. of gold was extracted from reefs of the area proved by the Geological Survey. Opencast mining operations are still proceeding (February 1943). The Amonikakine area lies to the immediate north of that of Borderland Syndicate. A certain amount of prospecting had been done when the writer started work there. As a result of his report, this area was taken over by another syndicate, but little further work was accomplished before it ceased operating because of difficulties of wartime working.

Jan 1, 1946

INTRODUCTION This chapter summarizes porphyry copper deposits within the State of Alaska. Prospecting for porphyry copper-type deposits in Alaska germinated during the 1940's, grew slowly during the '50's, boomed during the '60's, and matured in the '70's. Although large expenditures have been made in the search for porphyry-type deposits, most accrued data lies dormant in company files. However, an adequate base exists in the literature for a general synthesis of areas that contain porphyry prospects. To simplify the summary, porphyry molybdenum deposits as defined by Clark (1972) are omitted. Description of deposits in their geologic setting permits some correlations between deposit characteristics and crustal environment. These correlations allow speculation about the genesis of the deposits. The summary also attempts to group deposits on the basis of general mineralogic characteristics because diorite model deposits are separated from quartz phenocryst-bearing hosts. Data presented in this chapter summarize observations by the author, published descriptions of specific areas and deposits as noted in the bibliography, and comments by various government geologists. E. M. MacKevett, Jr., D. H. Richter, and H. C. Berg of the US Geological Survey have been particularly helpful. Because few comprehensive descriptions of individual porphyry copper deposits exist for this area, much of the data presented is new to the literature. Details of structure, isotopic geochemistry, and petro- genesis for individual deposits are largely lacking and even the general geology of some belts is not well understood. Details on petrography of Alaskan porphyry copper occurrences are inadequate for construction of ternary diagrams (e.g., Figs. 36a, b, pp. 103, 104, for the northern Cordilleran orogen). Petrographic descriptions summarized in the text are largely from published descriptions whose sources are cited. Porphyry copper-type deposits in Alaska include deposits with pervasive pyrite that contain disseminated copper (but not necessarily coproduct molybdenum). Available data preclude differentiating the deposits by size. No Alaskan porphyry copper deposit is now in production but this is believed to be, in part, a function of economics. In some cases available geologic information is in- adequate for classifying deposits. Some de- posits included with porphyry copper may, with further exploration, be demonstrated to be some other genetic type. Alaska has three distinct porphyry copper provinces: the Hogatza plutonic belt, the Continental Margin belt, and the Interior belt. Each belt contains deposits with characteristic geologic features distinct from those of other belts. Fig. 24 shows the continental margin belt to extend inland from

Jan 1, 1978

For four years your Committee has been engaged in the study of problems connected with the educational preparation of professional geophysicists. The Present report represents the conclusions drawn from the investigations and deliberations undertaken since it was first organized. These studies have shown that the evolution of geophysics has proceeded along lines that differed from those marking the advance of classical geology. The latter science developed as a descriptive one, dealing with directly observable terrestrial phenomena, and the elementary, rational explanations that could be offered therefor. The fact that these phenomena were also chemical and physical in nature was seldom given more than passing acknowledgment. During the last half century, however, a new approach to problems of terrestrial phenomena has become of greater significance. This new attack has come through the sciences of physics and chemistry, as the people trained therein have investigated the facts of the earth as problems in their respective sciences. This development has been chiefly at the hands of European investigators, and European universities have long recognized it by establishing departments or institutions of geophysics. In the universities of North America, their arbitrary departmentalization into fields of physics, chemistry, astronomy, geology, etc., has prevented the academic recognition of such domains of science as geophysics and geochemistry. In consequence, the development of these subjects in the United States has been largely at the hands of nonacademic institutions, while the universities themselves are evidently in a state of confusion as to how the subject should be handled. In some places an attempt to teach geophysics is made in the physics department, in others in the geology department, in some in the engineering school, and occasionally as a cooperative effort; a Department of Geophysics is seldom found in North America. In some instances, proper academic plan. ning has been precluded by interdepart. mental jealousies, or by lack of appreciation of the significance of the subject. For the background upon which these conclusions are based, the reader is referred to reports previously issued or SPonsored by Your Committee. The "First Report of the A.I.M.E. Mineral Industry Education Division's Committee of Geophysics Education, 1939," summarizes the replies received to question-

Jan 1, 1946

By Charles Fettke

The deposits described occur in a belt starting 1 ½ miles east of Juncos and extending 6 miles in a southeasterly direction. They are of the contact metamorphic type, being associated with a limestone and calcareous tuff that is interbedded with andesite tuffs and andesites which have been invaded by a quartz diorite intrusion. Of the fire occurrences examined, the largest can be traced for a horizontal distance of 2000 ft. No mining has, been done, but some of the outcrops lead to the belief that deposits of commercial size are present. IN CONNECTION with the gathering of data for a report on the geology of the Humacao district of southeastern Porto Rico during the summer of 1916, under the auspices of the Scientific Survey of Porto Rico and the Virgin Islands, conducted by the New York Academy of Sciences, the writer had an opportunity to make a brief examination of the magnetite deposits of the eastern portion of the island. Inasmuch as these deposits have attracted some attention as possible future sources of iron ore, and as there is only scanty reference made to them in literature,1 a short description based on this reconnaissance survey was deemed to be worthy of record. The magnetite deposits of eastern Porto Rico occur in association with a belt of limestone, trending approximately S 53° E, which begins 1 ½ miles east of Juncos and can be traced for about 6 miles toward the coast. Four outcrops of magnetite were observed, which are designated

Jan 2, 1924

Since production curtailment for other than engineering reasons is gradually disappearing, and more and more wells are now producing at capacity and showing declining production rates, it was considered timely to present a brief review of the development of decline-curve analysis during the past three or four decades. Several of the commoner types of decline curves were discussed in detail and the mathematical relationships between production rate, time, cumulative production and decline percentage for each case were studied. The well-known loss-ratio method was found to be an extremely valuable tool for statistical analysis and extrapolation of various types of curves. A tentative classification of decline curves, based on their loss ratios, was suggested. Some new graphical methods were introduced to facilitate estimation of the future life and the future production of producing properties where curves are plotted on semilogarithmic paper. To facilitate graphical extrapolation of hyperbolic-type decline curves, a series of decline charts was proposed, which will make straight-line extrapolation of both rate-time and rate-cumulative curves possible. Introduction During the period of severe production curtailment, which is now behind us, production-decline curves lost most of their usefulness and popularity in prorated areas because the production rates of all wells, except those in the stripper class, were constant or almost constant. While production-decline curves were thus losing in importance for estimating reserves, an increasing reservoir consciousness and a better understanding of reservoir performance developed among petroleum engineers. This fact, together with intelligent interpretation and use of electric logs, core-analysis data, bottom-hole pressure behavior and physical characteristics of reservoir fluids, eliminated a considerable part of the guesswork in previous volumetric methods and put reserve estimates, based on this method, on a sound scientific basis' At the same time, a number of ingenious substitutes were developed for the regular production-decline curve, which made it possible to obtain an independent check on volumetric estimates in appraisal work, even though the production rates were constant. with the now steadily increasing demand for oil to supply the huge requirements of this global war, proration for reasons of than prevention of underground waste is gradually disappearing. More and more wells are, or will be, producing at capacity or at their optimum rates, as determined by sound engineering practice. With this trend, the character of producing wells seems to regain, more or less, its "individuality," and the old and familiar decline curve appears to have had a comeback as a valuable tool in the hands of the petroleum engineer. It may be timely, therefore, to retrace the development of decline-curve analysis in the past by presenting a brief chronological review of bulletins and papers published during the past three or four decades, which have

Jan 1, 1945