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By Clinton M. Ball

Magnetic iron-ore is found in many localities throughout this and other countries, in large bodies and in convenient proximity to other materials required for its conversion into iron and steel; and these bodies of ore would have great commercial value on account of their nearness to consuming markets if they were generally suitable in their natural state for use in the larger operations of steel-making. In the manufacture of iron and steel it has been found, however, that not all ores are equally valuable as sources of raw material for the finished products of furnace, forge and foundry; and, as is now well understood, this is because of the intrusion, in the process of formation of the ore-bodies, of substances which can enter into deleterious combinations with the iron itself, or form compounds associated with the iron oxide which will hinder, if they do not altogether prevent, the production therefrom of the higher grades of finished metal. It is only since the development of the modern method of steel-making by the Bessemer process that the art of the chemist has been called to a critical study of the nature and effect produced by the presence of these pernicious substances in the furnace while the iron is undergoing reduction to the metallic state. Phosphorus and sulphur are the most common and obnoxious elements, and the admixture of one or the other, or both of these, in small percentages and varying proportions, will greatly modify the final results of manufacture. It so happens that generally, although not always, these hurtful elements are found in compounds in the ore which are not magnetic, and this circumstance has led to the expenditure of much ingenuity and money over a long period of time, in attempts to utilize the attractive power of magnets to separate the magnetic oxide of iron out of its crushed ores and from sands, in

Jan 1, 1896

By Samuel S. Adams

Potash, the generic term for a variety of potassium-bearing minerals, ores, and refined products (Table I), owes its importance as an industrial mineral to the potassium requirement of growing plants. The term "potash" originally referred to potassium carbonate produced by the leaching of wood ashes. This process, for which the first U.S. patent was issued in 1790, was the basis for the largest United States chemical industry in the early nineteenth century. The agricultural use of potash soon eclipsed the chemical applications following the German discovery in 1840 that potassium is essential to plant growth. The initial discoveries of large deposits of soluble potassium minerals, essential for agriculture applications, were made in 1857 in Germany and in 1914 in the United States. More than 90% of the 20.4 million short tons K2O produced in the world in 1970 (Eilertsen, 1971 ) was derived from marine evaporite deposits and approximately 90% was used in fertilizers. The potassium content of an ore, mineral, or product is customarily expressed as % K,O, a unit of measure which is neither a natural nor synthetic compound of potassium (1 .O% K is equivalent to 1.2046% K,O) . Geology Potassium, the seventh most abundant element in the earth's crust, is present in silicate minerals in igneous, sedimentary and meta- morphic rocks. Potassium is also a major constituent of many surface and subsurface brines (Table 2). Economic potash deposits are essentially restricted, however, to widespread, thick accumulations of marine chloride evaporite deposits. These deposits yield high grade, large tonnage ore bodies, many of which are amenable to low cost mining and beneficiation. The products from these deposits are, moreover, ideal for use in fertilizer because of the high relative solubility of the potassium chloride and sulfate evaporite minerals. World potash production and reserves for such de- posits so vastly overshadow other sources of potassium that the following discussion will be limited largely to potash deposits in marine evaporites with brief reference to certain potash-rich brines. Approximately 85% of current domestic production is from bedded salt deposits and much of the balance is from brines. Marine evaporite deposits are accumulations of salt minerals deposited in structural sedimentary basins through the evaporation of sea-water or mixtures of seawater and other brines. The salt minerals are precipitated in assemblages and sequences of assemblages as determined by the compositions of the brines and the solubility relations in the salt systems (D'Ans, 1933). The evaporation of seawater normally yields carbonate minerals as the first precipitates (Table 3). Further evaporation and concentration of the brine leads to the precipitation, in succession, of sulfate, chloride, and supersaline mineral assemblages including the salts of potassium and magnesium. The common minerals, ores, and products of potassium deposits are listed in [Table 1]. Many potash deposits contain accessory evaporite minerals together with a variety of detrital and authigenic silicates (Braitsch, 1971).

Jan 1, 1975

As reported in Drift last month demolition of old buildings on the 47th St. site has been completed, and detailed plans and studies for the new structure are well underway. As this issue was being sent to press the $5 million industry- business phase of the fund campaign had passed the half- way mark toward its goal. Target date for the building program is 1960.

Jan 5, 1958

United Engineering Trustees, Inc Engineering Foundation Engineering Societies Research Board Other Committees United Engineering Trustees, Inc. ARTHUR S. DWIGHT GEORGE D. BARRON J. V. N. DOER Engineering Societies Library Board ROBERT PEELS PHILIP W. HENRY GEORGE C. STONE JOSEPH E. POGUE The Engineering Foundation H. C. BELLINGER GALEN H. CLEVENGER J. V. N. DORR

Jan 1, 1929

By G. C. Trevorrow

STRIP mining during 1943 increased considerably with further extension of mechanical loading in mines already partly mechanized; with the considerable introduction of mechanical loading into hand-loading mines; and with improvements in the use of loading equipment. Extension of the use of machinery both in strip mining and underground is due to reduction in labor supply and increased cost of labor, together with the increased demand for coal during the period of labor shortage.

Jan 1, 1944

New Products Equipment

Jan 8, 1951

By J. F. Havard

Gypsum is a useful industrial mineral found abundantly on the earth's crust. It is inexpensive to mine and process, and its calcined products have a wide range of readily controllable properties such as strength, density and setting time. It has proven to be such a useful material indeed, that ten American companies, operating some 57 calcining plants in 25 states in 1958, produced or imported in that year a total of 13,649,000 tons of the crude mineral valued at $39,361,000, which they then converted into manufactured products with a value of $329,070,000. Gypsum (CaSO4.2H2O) is calcium sulfate with two molecules of combined water, which are responsible for most of its useful properties. It is closely associated in most deposits with anhydrite (CaSO4), which contains no combined water and has limited commercial value in the United States. Man has long recognized the useful qualities of gypsum. It was utilized by the Egyptians in the construction of the pyramids and, later, by the Romans for important structures. Many of the ancient peoples prized gypsum for artistic and ornamental purposes, carving statuary from alabaster and making casts with plaster. The tabular variety, selenite, was used for windows, and the light transmitted through these windows reminded people of light from the moon (selene), hence the name selenite. The use of gypsum continued through the Middle Ages and into modem times. Benjamin Franklin was a famed exponent of gypsum because he applied ground gypsum to clover fields in the form of large letters which later read, in the more luxuriant growth, "land plaster used here." Gypsum is still used as an effective conditioner for some soils, but in recent decades, particularly in North America and Europe, it has become much more important as a major material for the building industry. Description Gypsum and anhydrite are closely associated minerals. Gypsum is found in a number of forms: massive rock gypsum, alabaster, selenite, satin spar, and gypsite. Anhydrite is found as massive rock or as smaller bodies or isolated crystals included in gypsum. Massive Rock Gypsum comprises most of the commercial gypsum and occurs as a sedimentary rock, interbedded in most places with shale, limestone or dolomite. This rock is soft and crystalline. Its color is white or shades of gray, pink, yellow, brown or other colors. Alabaster is a pure, compact and fine-grained variety suitable for use in sculpture or turning into artistic forms; it may be white or selected for attractive coloration. Selenite is gypsum crystallized in flat, transparent, flexible foliated plates, found in clays or in surface vugs in gypsum. Satin Spar is a fine silky fibrous variety with the axes of the crystalline fibers perpendicular to the vein or joint in which it has formed. Gypsite is an earthy mixture of gypsum with clay and sand in secondary formations; it is sometimes useful as a soil conditioner and has been used in making base-coat plasters. Pure gypsum contains 20.9 pct combined water, 46.6 pct sulfur trioxide (SO3) and 32.5 pct lime (CaO). Standard specifications (American Society for Testing Materials Designation C 22-50) read that minimum purity for material to be called gypsum is 70 pct CaSO4.2H20. Most of the commercial gypsum is 85 to 95 pct pure as produced. Impurities in

Jan 1, 1960

By Richard E. Gray, William S. McCann, Robert C. Speck, Robert W. Bruhyn

Subsidence of the ground surface is the inevitable result of high recovery longwall and room and pillar coal mining operations. Up to now, U.S. research into this phenomenon has been concerned primarily with documenting the magnitude and extent of ground movements and prediction of the attendant ground strains through traditional ap¬proaches that have been developed in Europe and the United Kingdom. Preoccupation with ground strain prediction has, unfortunately, diverted attention from the more meaningful objective of predicting the severity of damage to structures at ground surface and the prob¬able cost to repair such damage. An attempt has been made to rectify this situation by reviewing in detail one hundred thirty four cases of subsidence damage to dwellings above active mines in western Pennsylvania, identifying the types of damage and the circumstances under which damage took place. The data reveal that damage to dwellings virtually always includes basements in addition to the readily apparent effects to the superstructure. In 90 percent of the subsidence cases, more than half the repair cost is associated with damage to subgrade components. A damage classi¬fication system has been devised that relates observed damage to severity and repair cost in a uniform manner for conditions in the Northern Appalachian Coal Field. Damage severity has been examined in the context of depth to the mine, the character of the near¬ surface overburden materials, mining type and other parameters.

Jan 1, 1983

By K. C. Li

TITANIUM, because of its high strength, weight ratio, and high melting point, became the metal of the jet age. Zirconium, because of its low neutron cross section and high corrosion resistance to hot water, became an integral part of the nuclear era. Since both metals are very similar chemically, more or less the same process is used for their production. The sudden rise of this new industry of titanium and zirconium seems to have caused some uncertainty as to the future development of processes for making these metals. Although zirconium was discovered in 1789 and titanium in 1790, it was not until 1945, six years after W. J. Kroll patented his process, that F, S. Wartman of the U. S. Bureau of Mines perfected the technique of producing ductile titanium, and it was not until 1946 that Kroll perfected the technique of producing ductile zirconium in commercial quantities. Since then the Government and private industry have spent millions of dollars each year constantly searching for new methods, with the hope that some day titanium can be produced as economically as aluminum and magnesium or as cheaply as stainless steel.

Jan 11, 1957

By D. D. Dunkin

Sandstone has been prepared for glassmaking purposes, and marketed from the White River Valley in Arkansas at Guion, Izard County, since about 1910—soon after the completion of the White River Branch of the Missouri Pacific R. R. Co. Until 1921, operations were somewhat spasmodic and ended in many failures. In that year a plant was built by the Silica Products Co., Inc., and since that time the operation has been continuous and steady. The land is held under leases, covering about 30 square miles of the best sandstone adjacent to the railroad. Most of the product is shipped to glassmakers. Geology The St. Peter sandstone is rather widely distributed in north central Arkansas and is exposed most prominently in outcrops along the slopes of the White River Valley and its tributarirs that form the division between the Boston Mountains to the south and the Salem Plateau of the Ozarks to the north. It is of Ordovician age and is generally underlaid by Cotter dolomite and capped by Plattin limestone, except in the vicinity of Bellefonte and Everton. At those places, it is a massive cross-bedded, laminated, saccharoidal sandstone; underlying it is the Everton limestone and overlying it, the Joachim magnesium limestone The sandstone at Everton contains numerous phosphatic pebbles and inclusions of sandy limestone. The irregularity of cross-section, the evidence of sorting action and the phosphatic pebbles appear to be indications of secondary deposition The St. Peter sandstone occurs as a massive formation in the picturesque bluffs along the White River Valley from near the eastern escarprnent of the uplift northwestmard into the Ozarks. The exposure shows a series of gentle anticlinal and synclinal folds. The greatest thickness is at the southeastern end, where it is over 100 ft. in many places. It thins out to the north and west and then to isolated and scattered deposits which cap the ridges and mountains of the Ozarks.

Jan 1, 1928

By Lewis Reeve

As. part of a program of investigation of the properties of electric arc welds carried out in the laboratories of the A. 0. Smith Corporation, considerable work has been done on the determination of the oxygen, nitrogen and hydrogen content of different types of weld metal, employing for this purpose the so-called "vacuum fusion method." It is the purpose of this paper to describe certain improvements that have been introduced in this method of determining the gas content of metals, with particular references to the steel specimens examined in this investigation. The method and apparatus used at the beginning of the investigation were essentially those of the Bureau of Standards as described by Vacher and Jordan.1 Later a number of changes were introduced which resulted in. more rapid evacuation of the graphite crucibles employed and which enabled larger volumes of gas to be dealt with than could be handled conveniently in the Bureau of Standards equipment. In addition, the analyzing of the gases evolved from a melt in the same apparatus as collected was abandoned in favor of analysis outside the equipment using standard methods of gas analysis. The time required for gas analysis in the apparatus itself, as described by the Bureau of Standards, was found to be considerable, and during this time the rest of the equip-ment was tied up, preventing its use for the analysis of further steel sam-ples. As a result of the modifications introduced, the time required for the analysis of a steel sample for gas content was reduced from about 8 hours to less than 3 hours. Subsequently, the whole procedure of melting the sample and collect-ing the gases evolved was modified so as to enable a distinction to be drawn between the easily reducible oxides such as iron oxide and the more stable oxides such as silica and alumina. At the same time evidence was obtained indicating the probable existence in the steels of other nitrides than those of iron alone and making possible their quantitative determination.

Jan 1, 1933

By Albert Sauveur

Floris Osmond, Honorary Member of the American Institute of Mining Engineers, born in Paris, March 10, 1849, died at Saint-Leu near that city, June 18, 1912. Taken suddenly ill with congestion of the brain while on his way from Paris to his home, he reached it in time to write on the typewriter his last wishes, one of which was that no biographical notice of his life should be published. Holding Osmond's memory sacred, as those who have known him will, is it our duty to conform with his desire ? Shall no mention be made in our Transactions of the beautiful life and great achievements of one of our most honored members? Is it not, on the contrary, incumbent upon us to disregard Osmond's instruction in this matter and to place on record our admiration for the nobility of his life, for his talents and for the importance of his work, that younger men may be inspired by it with a desire to be guided by worthy motives in the path of unselfish pursuits ? I cannot feel that in following this course I am disloyal to Osmond's memory and I am strengthened in this belief by the opinion of men of high honor whom I have consulted before undertaking the writing of this obituary notice. One of them, Professor Henry M. Howe, justifies my decision better than I could do it myself when he writes : " Let us look frankly at the matter. Here we have a most extraordinary life, a life of rare beauty and power of inspiration to the rest of mankind. In my opinion we should not deprive mankind of the stimulating influence of the example of M. Osmond simply because he shrank from publicity. Our young men see every day how greed and vulgar push succeed, and with what material rewards they are crowned. They see too rarely the more valuable crown which comes to self devotion. A permanent and public recognition of the beautiful qualities of Osmond's life cannot fail to appeal to the imagination of young men and to help to deflect them toward leading a noble rather than a sordid life. Therefore I feel that the Revue de Métallurgie and other bodies owe it to the public to give prominence to his career by means of biographical notices."

Jan 1, 1914

By J. J. Kanter

The choice of a nonferrous metal or alloy for a given Application is frequently predicated upon a consideration of properties other than merely the capacity to withstand stress. When ability to withstand stress is the dominant engineering requisite of the material to be used, economic considerations seldom lead to the choice of nonferrous metals and alloys. In most instances where a nonferrous metal is used it is because of some special quality of either corrosion resistance, electrical properties, thermal properties, antifriction, or fabrication advantage that commends its application. The mechanical properties, as a rule, present an incidental engineering consideration entirely secondary to the special quality deciding its use. Indeed, great ingenuity has often been exhibited by engineers and metallurgists in overcoming the mechanical shortcomings of a nonferrous base material. in order to take advantage of some outstanding property. . With this thought in mind, we might better appreciate some of the problems in stress design. encountered with nonferrous metals and alloys pertinent to a symposium on their creep characteristics. Our considerations must necessarily be far from complete because of the broad range of materials in the nonferrous category for which creep properties assume a technical interest. Creep deformation of these metals can be subject for study at temperatures ranging from ambient to incandescent, depending upon which one is under consideration. Whereas the steel metallurgist thinks of creep as an essentially high-temperature engineering consideration, the same is not necessarily true in the field at hand. The diversity of the creep problems in the nonferrous field is perhaps accountable to some extent for its virginity as a symposium subject. Each research has necessarily been sponsored by some organization or group interested either in promoting the use of a certain nonferrous base or in obtaining data toward the solution of a mechanical difficulty encountered in applying a material indispensable for its special attributes. Perhaps as many techniques of creep testing have been used as there are base metals implied under "nonferrous." Some of the creep problems that have occasioned researches are associated with steam-pressure vessels such as tubes, drums, castings, and forgings of copper-base and nickel-base alloys, cable sheathings of lead and lead-base alloys, electrical transmission lines of copper and aluminum, engine parts die-cast from alloys based on zinc, aluminum, copper— soldered and brazed joints-—as well as numerous duties at extremely high temperatures met with alloys based on cobalt, nickel, tungsten, molybdenum, platinum, and other precious or semiprecious metals. Postwar technology will have the benefit of much creep research on nonferrous metals, which for reasons of security cannot be discussed on this occasion. Suitability OF Metals As already intimated, the bulk of the constructional metal that ordinarily is

Jan 1, 1945

By R. W. Raymond

Through the courtesy of Mr. James H. Mayo, a member of the Institute, who is in charge of the operations of the Mindrinetti Company in the Saramacca district of Dutch Guiana, I have received specimeris of certain peculiar pseudomorphs of limonite after pyrite, which occur abundantly in the auriferous deposits of that. region.* I am indebted to Mr. H. Tweddle, a geiltleman- connected with the same company, for some particulars of interest con-

Jan 1, 1899

By Carl Zapffe

The manganese ore reserves of Lake Superior, because of their location and nature, have recently achieved a rnarked degree of importance as compared with the world's manganese reserves. To appreciate fully the significance and the adequacy of this reserve, one should understand how such ores are used, where obtainable, the quantity used, possible avenues for increasing use or application, and the chemical and physical characteristics of the available ores. Only with those data at hand, is it possible to arrive at a convincing answer to the question whether the reserves of manganiferous iron ores are adequate to satisfy the annual demand of the presently known iron ores for the full life of the latter. That they should last is vital; and to ascertain whether they will last was the purpose of the present investigation, which marks the first attempt to study these Lake Superior reserves. The Lake Superior region possesses and supplies the full assortment of iron ores needed for the conversion of ore into pig iron and steel ingots and castings. These ores are named bessemer, low-phosphorus and high-phosphorus non-bessemer, manganiferous and siliceous; and to include the term aluminiferous would be in keeping with the most recent nomenclature adopted by some dealers. About 35 or 40 years ago, perhaps less, most of the Lake Superior ore which is being used today was the material then considered either useless or too poor for immediate use; perhaps it was considered no more than a future reserve. An examination of the analyses of ores and the guarantees in the sales of those older times convince one that the opinions of those days must have been governed by only small differences in analyses. Some grades of ores used today in substantial amounts were used most sparingly only one or two decades ago. The relative quantities of the different ores used are ever changing; and, bit by bit, the metallurgy and the opinions are ever changing and the prejudices against certain ores and practices decrease. This is unquestionably more pronounced for the manganiferous ores than for any other kind. If, when using the present data for manganiferous ores, we will only be content to make allowances for the same experiences other kinds of ores

Jan 1, 1927

By S. G. Malghan, A. L. Mular

Size distribution and surface area measurements play an important role in the characterization of crushed and ground granular materials properties. This paper outlines sampling methods of granular materials followed by a detailed treatment of principles of size and surface area measurements of a wide range of sizes from crushers feed to ball-mill ground sub-micron particles. Currently available equipment for size distribution and surface area analysis is described and critically examined with respect to advantages, range of application and precautions in their use. Equipment for on- stream size analysis is also evaluated. Finally, a list of criteria are given for selection of particles size and surface area measuring devices for a particular application.

Jan 1, 1982

By Robert T. Gdagher, Allison Butts

EDUCATIONAL trends as reflected in curricular changes are of interest and importance in engineering educa¬tion both as matters of record and as considerations for the future. The data on which the evidence of this report is based were obtained by sending questionnaires to all schools in the United States granting the undergraduate degree in mining engineering, metallurgy, or metallurgical engineering. The questionnaire had two parts, one inquiring as to the general nature of revisions made or planned, and the other asking for information on specific courses added to or dropped from the curriculum, or given more or less time than formerly. The frequency with which curricular changes are made, even in normal times, is notable. Although it was expected that the period since 1939-40 would show numerous revisions, it was somewhat surprising to find that of 62 mining or metallurgical curricula in existence in 1939-40 and reported in the present survey, 58 had been revised or are shortly to be revised, 52 having already been changed during this period. Moreover, approximately half of the mining schools that have already revised their curricula, and probably a similar proportion of the metallurgical schools, are about to make further important changes.

Jan 1, 1948

By C. R. King

Most of the acid volcanic glasses such as obsidian, perlite, pitchstone, pumice, and pumicite (volcanic ash) are susceptible to some expansion if suddenly subjected to a suitably high temperature in a properly designed furnace, and subsequently suddenly cooled. Expansion results from the action of chemically combined or dissolved water expanding as a vapor within the softened heated rock particles. This expansion forms countless minute bubbles within the pasty mass of the natural glass particles. If the particles are cooled before these bubbles can escape, the resulting products are cellular, more or less spherulitized glass froths or hollow glass spheres of many types. Chemically, they are essentially aluminum silicates containing about 70 to 75 pct silica, 10 to 16 pct alumina, and 2 to 7 pct sodium plus potassium oxides. They are relatively resistant to attack by acids or alkalies, are resistant to heat up to over 1000°F, and are completely inert to insect or fungus attack.

Jan 1, 1949

By J. Richard Lucas

The coal industry, one of the great basic industries in the nation, plays a major role in the American economy. Coal is the principal fuel used in generating tremendous quantities of low-cost power so necessary to the nation. Two-thirds of the electrical energy and one-fourth of all energy consumed in the nation is produced from coal. Large-scale production of steel, cement, and chemicals is vitally dependent upon this natural resource. Because of extensive reserves and low mining cost, it is one of the few natural resources in which the United States is a significant exporter. During 1965 in excess of 500 million tons of coal were produced, almost 10% over the previous year; more than 50 million tons were shipped to foreign markets. The utility market gained approximately 8% during the year for a total of 242 million tons.

Jan 2, 1966

By T. Sterry Hunt

IN my address on the " Geognostical Relations of the Metals," delivered before the Institute on the 20th of February last (Vol. I Transactions, p. 331), I spoke of the rocks in the vicinity of Thunder Bay, Lake Superior, where I indicated two series of uncrystalline rocks resting upon the Huronian schists, the lower one consisting of dark-colored argillites and sandstones overlaid, apparently in slight discordance, by nearly horizontal red and white sandstone and marls, which were compared with those of Sault Ste. Marie, and those of the Portage Lake district, on the south shore. These latter sand-stones, according to Brooks and Pumpelly, overlie unconformably the Keweenaw series of copper-bearing amygdaloids, sandstones, and conglomerates, and are in turn overlaid by the Trenton limestone. I then proposed to call this lower series of Thunder Bay, that is to say, the dark-colored argillites and sandstones which are traversed by the silver-bearing lodes of that region, the Animikie group. Shortly after the publication of that address I received an abstract of a paper on the geology of that region by Professor Robert Bell, read before the Montreal Natural History Society, February 24th. He there confirms the statement made in my address that the gold of Lake Shebandowan occurs in the Huronian, which is also seen to be cut by the silver-bearing lodes just mentioned. Professor Bell, in this paper, proposes to designate both what I have called the Animikie group, and the overlying red and white sandstones, by the name of the Nepigon group, for the reason that the upper series is best displayed about Lake Nepigon. This latter series is by Logan supposed to be overlaid by the copper-bearing amygdaloids with conglomerates and sandstones of the north shore (apparently identical with those of Keweenaw) ; and the whole together, including the Animikie group, constitute his Upper Copper-bearing group. These copper-bearing strata are by him supposed to be overlaid by the red and white sandstones of St. Mary, which are apparently the same with those sandstones which, according to Brooks and Pumpelly, overlie unconformably the similar cupriferous rocks of Portage Lake, and are, in their turn, overlaid by the Trenton limestone. Thus the sandstones which at Thunder Cape overlie the Animikie group are by Logan placed in the midst of the Upper Copper-bear-

Jan 1, 1874