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By B. D. Cullity, K. S. Sree Harsha

When a copper or aluminum single crystal is swaged into wire, the resulting deformation texture depends on the original orientation of the crystal. The<100> and <111>orientations me essentially stable, while <110> is unstable. The greater the <100> content of the deformation texture, the stronger the wire is in torsion. the greater the<111>content, the stvonger it is in tenszotz. The preferred orientation (texture) of fcc wires, either after deformation or recrystallization, is usually a double fiber texture in which some grains have <100> parallel to the wire axis and others have <111>. The relative amounts of these two texture components, as reported by different investigators for the same metal, vary considerably. Previous work in this laboratory&apos; has shown that the starting texture of a wire, i.e., the texture which it has before deformation, can have a decided influence on the texture produced by deformation. In particular, it was found that the deformation texture of copper wire is essentially a single <100> texture, if the wire before deformation contains only a <100> component. This is true even when the deformation is carried to more than 98 pct reduction in area. This paper reports on further studies of the role played by the starting texture. Copper and aluminum single crystals of various orientations have been cold swaged into wire, and quantitative measurements of the resulting deformation textures have been made. The tensile and torsional properties of the deformed wires have also been measured, and the relation between these properties has been correlated with the texture of the wire. These measurements were made in order to demonstrate that a cold-worked wire can be made relatively strong in torsion and weak in tension, or vice versa, by proper selection of the texture before deformation. MATERIALS The copper was of the tough-pitch variety, containing, by weight, 99.962 pct Cu, 0.003 pct Fe, 0.025 pct 0, and 0.0021 pct Si. The aluminum contained more than 99.99 pct .&apos;41; the only reported impurities were 0.001 pct Fe, 0.001 pct Si, and 0.003 pct Zn, by weight. Large single crystals of these metals were grown by the Bridgman method in graphite crucibles and a helium atmospliere. Cylindrical specimens of predetermined orientation, about 1.5 in. long and 0.36 in. in diameter, were machined from the as-grown crystals and then etched to 0.25 in. to remove the effects of machining. Their orientations were checked by back-reflection Laue photographs, and they were then swaged to a diameter of 0.050 in. (96 pct reduction in area). 111 order to study the "inside texture" of the deformed wires, they were etched, after swaging, to a diameter of 0.040 in. before the texture measurements were made. TEXTURE MEASUREMENTS The fiber texture which exists in wire or rod can be represented by a curve showing the relation between the pole density I, for some selected crystal-lographic plane, and the angle $ between the pole of that plane and the wire axis (fiber axis). Such a curve will show maxima at particular values of , and these values disclose the texture components which are present. The relative amounts of these components can be determined2&apos;3 from the areas under the maxima on a curve of I sin F vs F. It is seldom necesszlry to measure I over the whole range of F from 0 to 90 deg, since the existence of maxima in the low-F relgion can be inferred from measurements confined to the high-F region. The X-ray measurements were made with a General Electric XRD-5 diffractometer and filtered copper radiation, according to one or the other of the following procedures: 1) A method developed in this laboratory,4 involving diffraction from a single piece of wire. 2) A modification of the Field and Merchant method.5 This method was originally devised for the examination of sheet specimens, but it can easily be adapted to the measurement of fiber texture. Three or four short lengths of wire are held in grooves machined in the flat face of a special lucite specimen holder. The axes of the wires are parallel to the plane defined by the incident and diffracted X-ray beams, and the holder to which the wires are attached can be rotated step-wise about the diffractometer axis for measurements at various angles 9.

Jan 1, 1962

By Herbert Clark Hoover, Lou Henry Hoover

QUESTIONS as to the methods of smelting ores and of obtaining metals I discussed in Book IX. Following this, I should explain in what manner the precious metals are parted from the base metals, or on the other hand the base metals from the precious&apos;. Frequently two metals, occasionally more than two, are melted out of one ore, because in nature generally there is some amount of gold in silver and in copper, and some silver in gold, copper, lead, and iron ; likewise some copper in gold, silver, lead, id iron, and some lead in silver ; and lastly, some iron in copper2. But I will begin with gold. Gold is parted from silver, or likewise the latter from the former, whether it be mixed by nature or by art, by means of aqua valens3, and by powders which consist of almost the same things as this aqua. In order to preserve the sequence, I will first speak of the ingredients of which this aqua is made, then of the method of making it, then of the manner in which gold is parted from silver or silver from gold. Almost all these ingredients contain vitriol or alum, which, by themselves, but much more when joined with saltpetre, are powerful to part silver from gold. As to the other things that are added to them, they cannot individually by their own strength and nature separate those metals, but joined they are very powerful. Since there are many combinations, I will set out a few. In the first, the use of which is common and general, there is one libra of vitriol and as much salt, added to a third of a libra of spring water. The second contains two librae of vitriol, one of salt-petre, and as much spring or river water by weight as will pass away whilst the vitriol is being reduced to powder by the fire. The third consists of four librae of vitriol, two and a half librae of saltpetre, half a libra of alum, and one and a half librae of spring water. The fourth consists of two librae of vitriol, as many librae of saltpetre, one quarter of a libra of alum, and three-quarters of a Mbra of spring water. The fifth is composed of one libra of saltpetre,

Jan 1, 1950

By A. F. Taggart

This paper describes the result of a series of experiments run in the laboratory of the School of Mines, Columbia University, during the winter of 1927-28. It shows that the several operating adjustments of a pneumatic table produce effects in the action of a given coal that may be grouped into two classes, viz.: stroke length, speed and rocker-arm angle, which affect longitudinal travel; air supply and table slope (transverse and longitudinal), which determine transverse travel. The magnitude of the effect of the different adjustments varies. Some of the adjustments affect stratification of the bed, both as respects size and specific gravity of the bed components, as well as direction of travel. Operation of a pneumatic table is fundamentally different from that of a wet table in that the former exerts, through the air supplied, a force on the particles upward away from the deck which is lacking on the wet table while, on the other hand, it lacks the positive control over cross travel that is supplied by the wash and feed water. Apparatus The pneumatic table used is shown in Fig. 1. Deck A is 20 by 12 in. and consists of nainsook supported on slats that register with the riffles. Fig. 2 is a photomicrograph of the nainsook used. It shows that the cotton threads average about 0.13 mm. dia. and the apertures about 0.17 mm. The deck carries 12 riffles consisting of wooden strips, 3/16 in. wide and 1/4 in. high, laid parallel to the feed side of the table. The riffles terminate along a line starting on the feed side at a point 11 in, from the mechanism end and running to the corner formed by the coal side and slate end. Taper starts from a line that runs parallel to their terminal line through the junction of the upper riffle with the mechanism end. The height at the terminal line is about 1/32 in. The deck with its supporting slats is carried on a framework consisting of rails A, sloping end rails B, and adjustable metal strips C, which latter permit variation in transverse slope. This frame is enclosed at the edges by means of heavy canvas, indicated in the sketch by wavy lines, which makes a flexible conduit between the deck and the stationary air chamber,

Jan 1, 1930

By C. A. Zapffe

BOTH the foundryman and the theoretical metallurgist are now generally agreed that the anomalous "rising" or "bleeding" of certain ferrous castings of killed metal is primarily attributable to hydrogen. How and why the phenomenon occurs, however, have not been made clear. The following discussion is intended to harmonize foundry experience with metallurgical theory so that the foundryman may possibly improve his ability to prognosticate whether a certain casting may bleed or not. BLEEDING, RISING, AND PIPING The "rising" to be discussed here is not to be confused with the action in rimming ingots as a result of the carbon-oxygen reaction, although a conclusion will be drawn that may apply to the art of controlling the rimming action. Only killed metal is considered, which includes both steels and irons. In Fig. I, three killed, chill-cast ingots are shown: a porous ingot whose evolution of gas during late stages of solidification has ejected metal through the top; an ingot in which moderate gas evolution during solidification has lifted the mushy central metal, i.e., it has "risen"; and, third, a sound ingot with good piping characteristics. The first type is referred to as "bleeding," and generally infers that a solid skin had first formed through which the liquid metal later erupted. There is no fundamental distinction between bleeding and rising in reference to killed metal.* POROSITY Hydrogen appears as a cause of bleeding because the gas evolution simultaneously leaves a porosity of a type traceable to hydrogen. Twenty years ago, Melmoth1 noted that killed steel that rose unexpectedly in the mold, if returned while liquid to the furnace and heated further under a reducing lime slag, would again rise in the mold; but that if the ingot were allowed to solidify and was then remelted no rising occurred. A critical quantity of the responsible gas is therefore removed by the rising action. Melmoth associated rising with high silicon (0.7 to 0.9 per cent) and concluded that silicon increased gas absorption. Because silicon is a strong deoxidizer, oxygen must, therefore, be eliminated from consideration of the three common gases in steel-oxygen, nitrogen, and hydrogen. Butterworth2 later decided that pinhole porosity was caused by gases dissolved in the metal and that hydrogen was obtained from steam in the mold. Allen&apos;s classical work on copper castings,3 soon followed by

Jan 1, 1942

By J. W. Pamplin

SOME 40 miles east of Tampa is the center of the Florida pebble phosphate deposits. These are of Pliocene age and consist of several members of the Bone Valley formation.1 Physically the phosphate-bearing formation, locally called the "matrix," varies in thickness from nothing to about 25 ft., usually averages 10 ft., and consists mainly of clay, quartz and phosphate pebble, the latter particles varying in size from colloidal to one inch diameter. The pebbles range in color from dark gray, through white, to cream, and in hardness from that which must be broken with a hammer to that which can be scratched with the fingernail. They assay from 66 to 80 per cent bone phosphate of lime (called "B.P.L." in the trade) or tricalcium phosphate (Ca3P20s) and are secondary apatites. They form from 15 to 50 per cent by weight of the matrix, Over the matrix lies a varying thickness (5 to 40 ft.) of overburden composed of quartz and clay. Briefly, mining consists of two operations2 in open pits about 200 ft. wide by ½ mile or more in length. In the first step overburden is removed by large electric draglines at the rate of about 700 cu. yd. per hour. This is followed closely by hydraulic mining of the matrix at the rate of about 300 cu. yd. per hour. This matrix yardage is moved from an improvised sump in the floor of the pit to an ore-dressing plant, some-times a mile distant, by one, two or three "pit-cars" (pumping units) working on a 12-in. pipe line called the "rock line" to distinguish it from the high-pressure water line feeding the hydraulic giants, which is known as the "hydraulic line." This 700 yd. of overburden and 300 yd. of matrix-1000 yd. in all-amounts to about 1500 tons of material moved each hour. The over-burden is dumped into the mined-out pit alongside the pit being mined. The matrix moves to the ore-dressing plant at the rate of about 7 ½ long tons in 4000 gal. of water per minute-a ratio of approximately one to two by weight, or one to six by volume. This constitutes the "mill heads," but in the pebble district it is called the "matrix."

Jan 1, 1938

By T. L. Joseph

Blast furnaces are most efficient thermally when the CO2 in the top gas is highest. Oxygen introduced in the air blast is converted to CO in the combustion zones. The extent to which CO, generated in front of the tuyeres, is converted later to CO2 depends upon the ratio of ore to coke in the charge and the degree to which CO2, formed by reduction of iron oxides with CO, reverts to CO by the secondary reaction C + CO2 = 2CO. About 300 to 400 lb. of carbon&apos; per ton of pig iron is normally involved in the solution-loss reaction or direct reduction of FeO with carbon, which produces the same over-all results; that is, lower CO2 in the top gas. Rich2 has recently reported a reduction in fuel consumption at slower rates of blowing on two furnaces in spite of higher heat losses per ton of iron. Lower fuel consumption at slow operating rates was due to more complete reduction of the ore that resulted in higher CO2 in the top gas and consequently more efficient use of carbon. Kinney3 has reported substantial savings in fuel as a result of crushing and sizing the ore charge. Improvements in practice brought about by sintering magnetite concentrates, flue dust and fine ores have been due to the establishment of conditions favoring more complete reduction of the ore in the upper part of the furnace. The extent to which oxides and fluctuations in composition in pig iron affect the quality of steel and finished product needs further study. There is evidence that more thorough preheating and reduction of the ore in the upper part of the furnace tend to give a better quality of iron. Bogatzkii4 found from laboratory work that the amount of oxygen entering electrolytic iron, melted under various slags, was directly proportional to the concentration of free FeO in the slag and inversely proportional to the basicity of the slag. Herty and Gaines5 concluded that the silicate content of open-hearth steel before deoxidation is related to the concentration of silica in the pig-iron charge, indicating that most of the persistent inclusions are silica from the iron. They also found that

Jan 1, 1936

By T. L. Joseph

Blast furnaces are most efficient thermally when the CO2 in the top gas is highest. Oxygen introduced in the air blast is converted to CO in the combustion zones. The extent to which CO, generated in front of the tuyeres, is converted later to CO2 depends upon the ratio of ore to coke in the charge and the degree to which CO2, formed by reduction of iron oxides with CO, reverts to CO by the secondary reaction C + CO2 = 2CO. About 300 to 400 lb. of carbon&apos; per ton of pig iron is normally involved in the solution-loss reaction or direct reduction of FeO with carbon, which produces the same over-all results; that is, lower CO2 in the top gas. Rich2 has recently reported a reduction in fuel consumption at slower rates of blowing on two furnaces in spite of higher heat losses per ton of iron. Lower fuel consumption at slow operating rates was due to more complete reduction of the ore that resulted in higher CO2 in the top gas and consequently more efficient use of carbon. Kinney3 has reported substantial savings in fuel as a result of crushing and sizing the ore charge. Improvements in practice brought about by sintering magnetite concentrates, flue dust and fine ores have been due to the establishment of conditions favoring more complete reduction of the ore in the upper part of the furnace. The extent to which oxides and fluctuations in composition in pig iron affect the quality of steel and finished product needs further study. There is evidence that more thorough preheating and reduction of the ore in the upper part of the furnace tend to give a better quality of iron. Bogatzkii4 found from laboratory work that the amount of oxygen entering electrolytic iron, melted under various slags, was directly proportional to the concentration of free FeO in the slag and inversely proportional to the basicity of the slag. Herty and Gaines5 concluded that the silicate content of open-hearth steel before deoxidation is related to the concentration of silica in the pig-iron charge, indicating that most of the persistent inclusions are silica from the iron. They also found that

Jan 1, 1936

By F. N. Rhines, T. E. Leonitis

The oxide scale that forms upon magnesium at elevated temperatures is non-protective in the sense that the rate of oxidation is constant and thus does not decrease with the growth of the scale as it does with other common metals. This generality was first stated by Pilling and Bedworth&apos; and has been verified by Suzuki2 and by ScheiL3 Pilling and Bcdworth argued that the nonprotective characteristic could be predicted from the fact that magnesium oxide occupies less space than does the metal from which it springs, wherefore the scale is not expected to cover the metal so completely as to exclude all direct access to the atmosphere. Linear oxidation is thought by Scheil to be common to all cases where the reaction occurs at the oxide-metal interface. According to Suzuki," he product of high-temperature oxidation in the air is MgO contaminated with no more than traces of a nitride. When the metal is allowed to burn freely a fume composed of cubic crystals of Mg04 is given off. Delavaults observed that excrescences form upon liquid magnesium and alloys in thc course of oxidation. Beyond this it is known that the use of atmospheres containing small quantities of sulphur dioxide6 or carbon dioxide serve to retard the oxidation of solid magnesium and that beryllium&apos; and calciums minimize the oxidation of molten magnesium exposed to the air. Many studies have been devoted to the nature and rates of "protective" oxidation, as exemplified by the cases of copper and iron, wherein the rate is characteristically parabolic. The theory of parabolic oxidation is well developed.~ Linear oxidation, on the other hand, has received but little attention and the theories proposed by Pilling and Bedworth and by Schcil have yet to withstand careful examination. There exists no comprehensive survey of the high-temperature oxidation of magnesium (or of any other metal that exhibits linear oxidation) over a broad range of temperature, under a variety of atmospheric conditions and covering a large group of alloys. It has been the purpose of the present investigation to provide such a survey, with the object of gaining a fuller understanding of linear oxidation, especially as applied to magnesium. Experimental Procedure and Results The experimental studies undertaken were of two kinds: (I) measurement of the rate of oxidation as influenced by the 6c

Jan 1, 1946

By T. E. Leonitis, F. N. Rhines

The oxide scale that forms upon magnesium at elevated temperatures is non-protective in the sense that the rate of oxidation is constant and thus does not decrease with the growth of the scale as it does with other common metals. This generality was first stated by Pilling and Bedworth&apos; and has been verified by Suzuki2 and by ScheiL3 Pilling and Bcdworth argued that the nonprotective characteristic could be predicted from the fact that magnesium oxide occupies less space than does the metal from which it springs, wherefore the scale is not expected to cover the metal so completely as to exclude all direct access to the atmosphere. Linear oxidation is thought by Scheil to be common to all cases where the reaction occurs at the oxide-metal interface. According to Suzuki," he product of high-temperature oxidation in the air is MgO contaminated with no more than traces of a nitride. When the metal is allowed to burn freely a fume composed of cubic crystals of Mg04 is given off. Delavaults observed that excrescences form upon liquid magnesium and alloys in thc course of oxidation. Beyond this it is known that the use of atmospheres containing small quantities of sulphur dioxide6 or carbon dioxide serve to retard the oxidation of solid magnesium and that beryllium&apos; and calciums minimize the oxidation of molten magnesium exposed to the air. Many studies have been devoted to the nature and rates of "protective" oxidation, as exemplified by the cases of copper and iron, wherein the rate is characteristically parabolic. The theory of parabolic oxidation is well developed.~ Linear oxidation, on the other hand, has received but little attention and the theories proposed by Pilling and Bedworth and by Schcil have yet to withstand careful examination. There exists no comprehensive survey of the high-temperature oxidation of magnesium (or of any other metal that exhibits linear oxidation) over a broad range of temperature, under a variety of atmospheric conditions and covering a large group of alloys. It has been the purpose of the present investigation to provide such a survey, with the object of gaining a fuller understanding of linear oxidation, especially as applied to magnesium. Experimental Procedure and Results The experimental studies undertaken were of two kinds: (I) measurement of the rate of oxidation as influenced by the 6c

Jan 1, 1946

By C.A. Zapffe

Both the foundryman and the theoretical metallurgist are now generally agreed that the anomalous "rising" or "bleeding" of certain ferrous castings of killed metal is primarily attributable to hydrogen. How and why the phenomenon occurs, however, have not been made clear. The following discussion is intended to harmonize foundry experience with metallurgical theory so that the foundryman may possibly improve his ability to prognosticate whether a certain casting may bleed or not. Bleeding, Rising, and Piping The "rising" to be discussed here is not to be confused with the action in rimming ingots as a result of the carbon-oxygen reaction, although a conclusion will be drawn that may apply to the art of controlling the rimming action. Only killed metal is considered, which includes both steels and irons. In Fig. I, three killed, chill-cast ingots are shown: a porous ingot whose evolution of gas during late stages of solidification has ejected metal through the top; an ingot in which moderate gas evolution during solidification has lifted the mushy central metal, i.e., it has "risen"; and, third, a sound ingot with good piping characteristics. The first type is referred to as "bleeding," and generally infers that a solid skin had first formed through which the liquid metal later erupted. There is no fundamental distinc- tion between bleeding and rising in reference to killed metal.* Porosity Hydrogen appears as a cause of bleeding because the gas evolution simultaneously leaves a porosity of a type traceable to hydrogen. Twenty years ago, Melmoth&apos; noted that killed steel that rose unexpectedly in the mold, if returned while liquid to the furnace and heated further under a reducing lime slag, would again rise in the mold; but that if the ingot were allowed to solidify and was then remelted no rising occurred. A critical quantity of the responsible gas is therefore removed by the rising action. Melmoth associated rising with high silicon (0.7 to 0.9 per cent) and concluded that silicon increased gas absorption. Because silicon is a strong deoxidizer, oxygen must, therefore, be eliminated from consideration of the three common gases in steel—oxygen, nitrogen, and hydrogen. Butterworth2 later decided that pinhole porosity was caused by gases dissolved in the metal and that hydrogen was obtained from steam in the mold. Allen&apos;s classical work on copper castings,3 soon followed by

Jan 1, 1943

By C. A. Zapffe

Both the foundryman and the theoretical metallurgist are now generally agreed that the anomalous "rising" or "bleeding" of certain ferrous castings of killed metal is primarily attributable to hydrogen. How and why the phenomenon occurs, however, have not been made clear. The following discussion is intended to harmonize foundry experience with metallurgical theory so that the foundryman may possibly improve his ability to prognosticate whether a certain casting may bleed or not. Bleeding, Rising, and Piping The "rising" to be discussed here is not to be confused with the action in rimming ingots as a result of the carbon-oxygen reaction, although a conclusion will be drawn that may apply to the art of controlling the rimming action. Only killed metal is considered, which includes both steels and irons. In Fig. I, three killed, chill-cast ingots are shown: a porous ingot whose evolution of gas during late stages of solidification has ejected metal through the top; an ingot in which moderate gas evolution during solidification has lifted the mushy central metal, i.e., it has "risen"; and, third, a sound ingot with good piping characteristics. The first type is referred to as "bleeding," and generally infers that a solid skin had first formed through which the liquid metal later erupted. There is no fundamental distinc- tion between bleeding and rising in reference to killed metal.* Porosity Hydrogen appears as a cause of bleeding because the gas evolution simultaneously leaves a porosity of a type traceable to hydrogen. Twenty years ago, Melmoth&apos; noted that killed steel that rose unexpectedly in the mold, if returned while liquid to the furnace and heated further under a reducing lime slag, would again rise in the mold; but that if the ingot were allowed to solidify and was then remelted no rising occurred. A critical quantity of the responsible gas is therefore removed by the rising action. Melmoth associated rising with high silicon (0.7 to 0.9 per cent) and concluded that silicon increased gas absorption. Because silicon is a strong deoxidizer, oxygen must, therefore, be eliminated from consideration of the three common gases in steel—oxygen, nitrogen, and hydrogen. Butterworth2 later decided that pinhole porosity was caused by gases dissolved in the metal and that hydrogen was obtained from steam in the mold. Allen&apos;s classical work on copper castings,3 soon followed by

Jan 1, 1943

By W. G. Whildin

This paper will be confined to a discussion of the methods in use in the property of the Lehigh Coal & Navigation Co. in the Panther Creek valley. Only the methods used in mining the Mammoth vein will be .considered, as the methods in use in the smaller veins are adaptations of the same. Typical cross-sections of the coal basin are shown in Figs. 1, 2, and 3. The Mammoth vein varies in thickness. It is 21 ft. at one colliery, 50 to 125 ft. at another, and over 200 ft. at still another. Its normal thickness is 35 to 40 ft. At some points in the Panther Creek basin the Mammoth vein is made up of three splits-the Bottom, Middle, and Top, while in other portions the dividing strata between the benches amount to only 1 ½ to 2 ½ ft., and the vein is practically in one. The section of the Mammoth vein shown in Fig. 4 was taken at the Greenwood colliery, and shows a thickness of 60 ft. The miners know it by benches, as follows:. The Three-Foot, the Four-Foot, the Eighteen-Inch Slate, the Bony, the Grey Slate, the Grain Clear, the Five-Foot, the Seven-Foot, the Slaty or Dirty benches, the Blue Slate, and the Top bench. The present-day methods of mining are an outgrowth of the experiences of the last 100 years in this territory. The first attempt at mining, according to the company&apos;s maps, was made at Summit Hill in 1792, when open cuts and pits were made. Later the pillar-and-breast method was introduced. This and other methods will be discussed hereinafter. Drifts, slopes, and shafts, according to the requirements and physical conditions, are the main openings, from which the gangways are driven. The gangways (haulageways) and airways are driven along the strike of the vein; the gangways in the various veins on the same level being connected by tunnels through the intervening rock. The gangways and airways in thick veins are heavily timbered ;throughout. The sets of timber, consisting of a collar and two legs, are spaced 5 ft. apart, and later, after the ground :has settled, additional sets, called "liners" or "relief sets," are placed between, to relieve the strain on the original timbers, so that the result is a set of timber every 2 ½ ft.

Jan 12, 1914

By W. T. Lundy

THE forms in which sulphur is commonly found-native sulphur, sulphides of many metals and sulphates-are widely distributed throughout the world. The two first mentioned are the principal sources of sulphur. Substantial amounts of sulphur in some form are recovered from gases from industrial plants and from gases from smelters treating other minerals. In recent years, plants have been installed in the United States to recover sulphur in elemental form from sour gases."&apos; The amount of sulphur so produced is small at the present time but undoubtedly will increase in the future. The recovery of sulphur from gases is not covered in this chapter, which is confined to: (1) native sulphur deposits of Texas and Louisiana; (2) those of Italy; (3) other scattered deposits of native sulphur; and (4) pyrites deposits found in many countries of the world.30 Sulphur, a nonmetallic element, occurs normally in well developed bipyramidal or tabular crystals of the orthorhombic system, as well as in stalactitic and earthy masses. The mineral has a distinctive yellow color, which may be dark and discolored by impurities; the streak is white; the luster is resinous; and the fracture is conchoidal to uneven. Sulphur is translucent to opaque; has a hardness of 1.5 to 2.5, a specific gravity of 2.05, and an atomic weight of 32.06.16 The molecular weight of the solid is expressed by the symbol SS and that of the liquid and vapor ranges from S2 to S8, depending on the temperature. Sulphur melts at a temperature between 2340 and 248°F, depending on its crystalline state, to a liquid of dark amber color, the boiling point of which is 832°F. The viscosity near the melting point is about that of water and increases to 50,000 times that of water at a temperature of 380°F, subsequently falling rapidly to a low figure at the boiling point. Crystallization changes slowly from rhombic to monoclinic above 205 °F and in cooling the transformation is reversed. The mineral is a very poor conductor of heat and electricity; it is insoluble in water and nearly all acids and is soluble in cold carbon bisulphide and carbon tetrachloride. It ignites in air at a temperature of 478°F, burning with a distinctive blue flame with evolution of sulphur dioxide.47

Jan 1, 1949

By Ronald R. McNaughton

The most recent group of papers on the general subject of lead smelting were published in AIME Transactions, vol. 121, in 1936. The lecture deals with changes which have taken place in the Past 30 years in this industry. The subject matter covers the essential steps of charge preparation, sintering, blast furnacing, dross treatment, refining, and slag fuming together with the subsidiary or associated activities of analytical procedures, dust and fume collection, maintenance, and hygiene. IN 1936 the AIME published Transactions, vol. 121, entitled "Metallurgy of Lead and Zinc". In the preface to this volume the chairman of the Committee on the Reduction and Refining of Lead and Zinc, Carle R. Hay ward, said in part: ... since the World War few papers of major significance have appeared on the production and refining of lead and zinc, although many improvements in technique have been made, which have attracted little attention because they were merely developments of existing practice. Other changes of a more radical nature have also been made, but... they have been given little publicity. It seems appropriate, therefore, at this time that the AIME should sponsor a volume on lead and zinc metallurgy... . That the publication of this compilation was timely is attested by the rapidity with which the surplus stock was depleted. It has now become a collector&apos;s item. Although a comprehensive monograph on the occurrence, extraction, refining, and uses of zinc was published by the American Chemical Society in 1959,&apos; one could almost repeat Professor Hayward&apos;s words to describe the present situation in the literature of lead reduction and refining. So it is my intention today to discuss briefly some of the changes and improvements which have taken place in the metallurgy of lead in the interval since the publication of vol. 121. The lead blast furnace, which made its appearance in America about 1870, is still dominant in the reduction field. However there are other reduction methods in use today in special situations. In those rare circumstances where the material to be treated is very high grade, consideration might be given to the Bolidens electric furnace method2 or the Lurgi self-fluxing process3 or possibly to the rotary ore hearth. Each of these latter three processes makes use of the roast-reduction reactions with the result that fuel require-

Jan 1, 1969

By R. A. Meussner, R. J. Goode

Six intermediate phases occur in the Nb-Zn sysThese phases form by peritectic reactions at 1120°, spectively. The Nb Zn 15 phase appears as the minor phase in the eutectic structure, and the terminal phases remain nearly pure niobium and zinc even at high temperature. Vapor -pressure measurements on the four high-temperature phases (Nb Zn to Nb Zn 3) permitted estimates of the composition limits of these phases and the calculation of approximate values of AFO, AH°, and AS°. 1 HE present study of the constitution of the binary Nb-Zn system was a part of an analysis of the mechanism by which coatings of the Nb-Zn intermediate phases protect niobium against oxidation at high temperature.&apos; Since the primary interest in these phases was in coating service, attention in this study was given principally to the four phases stable at high temperature with only cursory attention to the two low-temperature phases. The solubility studies of niobium in zinc by Martin, Knighton, and Feder2 and the reports from the present study of the Nb-Zn coating represent the only published data pertaining to this system. Previously Hodge, Evans, and Hoskins, in an experimental survey, had noted that niobium was not resistant to attack by molten zinc, but no further observations were reported. EXPERIMENTAL PROCEDURES a) General. The nature of the binary Nb-Zn system precluded the use of more conventional methods of determining the phase equilibria such as thermal analyses of a series of cast alloys. An extrapolation of the liquidus data of Martin, Knighton, and Feder2 to higher temperatures suggested that the solubility of niobium in zinc would remain low in the entire temperature range of interest. The preliminary results of the present studies showed that all of the high-temperature intermediate phases form by peritectic reactions. Thus the sluggish nature of this type of reaction and the steepness of the liquidus indicated that thermal analyses would not yield reliable data. The peritectic reactions, of course, precluded the direct formation of samples of the individual phases from the melt. b) Materials. The niobium and zinc used in the present studies were of high purity. The niobium, in the form of 0.1-in.-diameter rods, contained 30 ppm 0, 30 ppm N, and 15 ppm C. Aside from 0.05 pct Ta, the metallic impurities (iron, titanium,

Jan 1, 1965

By Donald C. Barton

Success in the use of the Eötvös torsion balance method of mapping geologic structure depends largely on the accuracy in the interpretation of the observed results. Skill in that interpretation depends (1) on the knowledge of the types of the variation of gravity, the gradient of gravity horizontally, and of the differential curvature produced by bodies of different sizes, shapes, dimensions, and densities; (2) on the knowledge of the possible types of structural bodies which might produce the observed anomalies; (3) on the empirical knowledge gained by experience not only in the geological interpretation of torsion balance surveys, hut of interpretations of inadequate geological data; and (4) on a knowledge of the possible and probable types of geologic structures in the area of the survey. The knowledge of the anomaly which a known body will produce and conversely the knowledge of the body or bodies which will produce a known anomaly may be gained by empirical experience and by mathematical study. The knowledge gained by empirical experience is fragmentary and inexact. The geology of most structures actually is known very superficially. The surface geology may be known accurately. If the structure is petroliferous, the subsurface geology of the oil field will be known down to 3000, 4000, 5000 ft. or in a few oil fields down to 7500 ft., but the deeper geology will be unknown and the metamorphic, igneous, or massive limestone basement below the reach of the drill may contrast sharply in density with the overlying sediments. Away from the oil field, the subsurface geology is known only from scattered drill holes, which do not go to the basement. A fair but not necessarily accurate knowledge of the geology of the nonproductive area can be obtained by correlation of the wells but the degree of its accuracy in general is proportional to the density of the occurrence of the wells. The geology below the bottom of the wells however is unknown. An anomaly mapped by the torsion balance is the sum of the effects of the contrasts in mass of its whole geologic surroundings. If the dimensions of a body of abnormal density are large enough, depth or distance makes no difference in the effects on the gradient and differential curvature; and as a matter of fact, in many places, the basement and irregulari-

Jan 1, 1929

By Homer F. Staley, C. P. Karr

The casting alloy 88 copper, 10 tin, 2 zinc, commonly known in England as Admiralty metal and in this country as Government bronze, gun metal, or Naval Department composition G, has, at its best, many valuable properties. However, its physical properties are known to vary widely with slight changes in method of manufacture of the castings, such as slight variations in composition, variation in pouring temperature, kind of mold used, method of pouring and gating of molds, size and shape of castings, amount and kind of heat treatment, and so forth.&apos; The microstructure of castings made from this alloy is influenced by slight variations of composition, rate of cooling, and kind and length of heat treatment. This is best understood by reference to the equilibrium diagram. The part of the diagram in which we are interested and the effect of the thermal equilibrium relations on the physical properties of the alloy 88 copper, 10 tin, 2 zinc, have been discussed by Hoyt, Campbell, Primrose, and Rawdon.2 In Fig. 1 is given the equilibrium diagram of the copper-tin alloys. Briefly stated, the relations of composition and temperature changes are as follows. Compositions between A and a consist of but one constit ent—the a bronze, which is a solid solution of copper and tin, rich in copper. On cooling from the molten state these compositions gradually crystallize, at temperatures above 790°, into a mass of interwoven treelike crystals or dendrites. The cores of the dendrites are rich in copper and the percentage of tin gradually increases as the surfaces are approached. AS cooling progresses, after a11 the metal has crystallized, no further changes occur in the crystals other than diffusion within the crystals, which tends to erase the dendritic pattern and to render the structure more homogeneous. * Metallurgical Ceramist, U. S. Bureau of Standards, Associate Physicist, U. 8. Bureau of Standards. A. D. Flinn: Iron. Age (1915) 96, 1292-3. C. P. Karr: U. S. Bureau of Standards Tech. Paper 59, Pt. 1. S. L. Hoyt: Enging. (1913) 96, 667-7, 704-5. William Campbell: Trans. Am. Inst. Met. (1912) 6, 158-172. H. S. Primrose: Metal Ind. (1916) 14, 202-4. H. S. Rawdon: U. S. Bureau of Standards Tech. Paper 59, Pt. 11.

Jan 1, 1921

By D. L. McElroy

It is too broad a statement to say that the mine car is the most important unit in a haulage system, but almost every mining man will admit that it is one of the most important. The mine car is to the mine haulage system what the railroad car is to the railroads; the main purpose in each instance is to move the greatest number of ton-miles of material at the least cost. The data presented in this paper are taken from a study of mine haulage conducted by the School of Mines of West Virginia University at 42 mines in 8 coal fields of Wrest Virginia. The study was made possible by a graduate fellowship of the School of Mines and the cooperation of the mining companies of the state. Three important factors in the use of mine cars in West Virginia are: (I) the number of mine cars in use per loader; (2) the capacity of mine cars; (3) the distribution of mine cars. ("Loaders" in this paper refers to all men loading coal, whether manually or mechanically.) During the World War many mine managers were annoyed by the reduction of efficiency and production caused by railroad-car shortages. Today relatively little complaint is heard about a shortage of mine cars, yet possibly 50 to 75 per cent. of the mines in West Virginia are suffering from this cause of reduced production and increased costs. The railroads have solved their car shortage by placing in service more cars of larger capacity and better design. Many coal mines in West Virginia should solve a part of their cost problems by the same simple procedure. Such a procedure requires an initial outlay of capital, but there is little doubt that this will be repaid, with a good return on the investment. Determining Number of Cars Needed There can be no mathematical rule to determine the number of cars which should be in use per loader in a coal mine, because numerous factors such as concentration of mining, system of haulage, car capacity, speed of haulage, distance of working places from tipple, and so forth, affect materially the number of cars in use. These factors in turn are more or less determined by height of bed, character of roof and coal,

Jan 1, 1931

By Charles W. Wagner

A premature explosion might be described as an explosion that, occurs before the miner expects it. Notwithstanding that it is unexpected, a premature is generally within the miner&apos;s control. A hangfire explosion is a blast that occurs after the miner expects it,, and in all instances, except where the explosives or blasting accessories are defective, hangfire explosions are within the miner&apos;s control. Causes of Premature Explosions Generally, there are seven methods of shot-firing in anthracit,e mines; namely: (1) cap and fuse with dynamite, (2) fuse with pellet powder, (3) squib with black powder or pellets, (4) exploders and delays with dynamite or black powder, (5) exploders with dynamite, (6) delay ignitors with black powder or pellets, (7) electric squibs with black powder or pellets. Cap and Fuse.—This method of firing seems to produce the greatest number of premature explosions. This is not solely because of the method, but is the result of mispractices which are possible with this method of firing. The two most common mispractices followed with cap-and-fuse blasting are the firing of multiple holes and the use of short fuse.. In the firing of multiple holes by cap and fuse, investigations have shown that in nearly every instance where the miner was injured by this method of firing he remained too long at the face lighting the several fuses, so that the first shot went off before he could reach a place of safety. Such accidents could have been avoided either by accurate judgment by the miner of the relative lengths of the fuses or by the use of electric firing. Rules exist in nearly every mine forbidding the lighting of more than one hole at a time where the cap-and-fuse method of firing is practiced. Where it is desirable to fire more than one hole at a, time, electric firing should be used. It is difficult to understand why so many premature explosions result from the use of short fuses, inasmuch as the cost of fuse is practically a negligible item in the expense of a day&apos;s work. Notwithstanding this, however, we frequently find miners using short lengths of fuse in an effort to save one or two cents per hole, or about 15 to 20 # in a day. A practice

Jan 1, 1931

By W. C. Lacy

Urban development in semi-arid portions of the Southwest has upset a natural balance of geological conditions resulting in broad-scale and local subsidence or heaving ground conditions, Subsidence can be traced to two general causes: irrigation of reclaimed desert lands that have dry, low-density soils; and depression of the water table by ground water withdrawal. Accumulation of weathered volcanic tuff produces areas with swelling characteristics. Soil and subsidence studies made in the Tucson area in Arizona illustrate foundation problems typical of the Southwest that must be considered in the design of building codes. Anticipation of problems and the adoption of corrective measures in the design of engineering structures, establishment of pertinent building codes, and urban planning and zoning to obtain optimum land usage and conservation of natural resources demands a thorough understanding of geological conditions of a developing urban area. In the arid to semi-arid southwestern United States erosional and depositional processes result in special situations that require special precautions in building practices. A series of studies currently underway in the Tucson area, prompted by foundation failures and breaking of buried service lines, serves to illustrate some of these relationships between the geological environment and history and engineering problems. ENVIRONMENT The desert region of the Southwest is characterized by isolated mountain ranges rising abruptly from low valleys or plains — the ranges generally occupy less area than do the intervening valleys. In southern Arizona the valley floors step up from near sea level to 2000 ft or more in elevation, and the ranges may rise to over 7000 ft. Desert and steppe-type climates predominate — climate is controlled more by elevation than it is by latitude. Both climate types are characterized by a lack of precipitation, the former more so than the latter. Practically all the rain that falls in the region evaporates; runoff or recharge generally occurs only during the wettest period. Water table levels are generally being depressed. Vegetation is restricted and consists mainly of creosote bush, cacti and sage brush on the deserts, and mesquite, pinon juniper and various types of grass on the steppes. Precipitation varies from about 3 in. on the warm deserts to about 12 in. on the steppes. Most of this falls in the summer or winter, with only rare storms in other seasons. Summer thunderstorms, often accompanied by hail, bring cloudbursts which send torrents of water streaming down the mountains onto

Jan 1, 1964