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By Arhtur T. Allen

THE Kingsport formation, a part of the Knox dolomite of Ordovician age, is composed of 538 ft of dolomite and limestone. Numerous bands, layers and nodules of chert, arenaceous and shale zones are present. The characteristics displayed by these features have been useful in mapping, prospecting and mining. Perhaps a better understanding of the origin of these zones will increase their usefulness.

Jan 1, 1947

Jan 1, 1910

By Wilson D. Michell

The Magma copper vein trends east-west, dips 70" south, and cuts through a 6000-ft thickness of limestones, quartzites,. shale, diabase, and schist. The vein is itself a fault with a horizontal offset of 500 ft on the formation contacts in the two walls. There are two principal faults of large displacement and numerous smaller steep and flat faults that complicate the prediction of ore occurrence. A study of the geology, its systematic recording to facitliate ready reference, and graphic methods of interpretation of mineralization have aided the exploration, development, 2nd mining of the ore. In making predictions of the distribution of mineable ore bodies and their shape in critical areas, studies are made of "mineralization contours" and "mineralization trends," which are developed on a longitudinal section of the vein from variations in the concentration of the combined base metal content as shown by assays of available openings in the mine. Introduction This paper describes an example of geological work applied directly to mining and exploration problems in a deep vein deposit, and it is presented as being of interest especially to those engaged in working more or less similar veins. In 1944 to 1945 the writer spent a year as assistant to J. K. Gustafson in a thorough geological examination of the Magma mine. Much of the writer's subsequent independent work described in the present paper had its inception in ideas originated by Gustafson during that examination. Objectives of Geological Work at Magma Mine The objectives of geological work at Magma, as at operating vein mines of a similar nature, can be summarized as follows: 1. Direct assistance to the mining department by means of predictions as to the size, shape, grade, and location of ore bodies; by solution of fault problems and irregularities in the veins; by prepara-?ion of detailed ore-reserve estimates in specific areas; by keeping a complete record of the geology and assay results in the mine; and by guiding development work. In short, geology can aid in the realization of the prime purpose of the mining department, which is that of producing the greatest amount of ore in the most economical and expeditious manner possible. 2. Guidance for exploration, especially diamond drilling, in undeveloped areas of the mine. 3. Contributions to the understanding of the general geology of the deposit and its regional setting, including ore genesis, structure, and mineral relationships. Magma Ore Deposit The east-west trending Magma vein, dipping about 70" south, cuts through a 6000-ft thickness of concordant limestones, quartzites, shale, diabase, and schist, named in descending order. These

Jan 1, 1949

By Wilson D. Michell

The Magma copper vein trends east-west, dips 70" south, and cuts through a 6000-ft thickness of limestones, quartzites,. shale, diabase, and schist. The vein is itself a fault with a horizontal offset of 500 ft on the formation contacts in the two walls. There are two principal faults of large displacement and numerous smaller steep and flat faults that complicate the prediction of ore occurrence. A study of the geology, its systematic recording to facitliate ready reference, and graphic methods of interpretation of mineralization have aided the exploration, development, 2nd mining of the ore. In making predictions of the distribution of mineable ore bodies and their shape in critical areas, studies are made of "mineralization contours" and "mineralization trends," which are developed on a longitudinal section of the vein from variations in the concentration of the combined base metal content as shown by assays of available openings in the mine. Introduction This paper describes an example of geological work applied directly to mining and exploration problems in a deep vein deposit, and it is presented as being of interest especially to those engaged in working more or less similar veins. In 1944 to 1945 the writer spent a year as assistant to J. K. Gustafson in a thorough geological examination of the Magma mine. Much of the writer's subsequent independent work described in the present paper had its inception in ideas originated by Gustafson during that examination. Objectives of Geological Work at Magma Mine The objectives of geological work at Magma, as at operating vein mines of a similar nature, can be summarized as follows: 1. Direct assistance to the mining department by means of predictions as to the size, shape, grade, and location of ore bodies; by solution of fault problems and irregularities in the veins; by prepara-?ion of detailed ore-reserve estimates in specific areas; by keeping a complete record of the geology and assay results in the mine; and by guiding development work. In short, geology can aid in the realization of the prime purpose of the mining department, which is that of producing the greatest amount of ore in the most economical and expeditious manner possible. 2. Guidance for exploration, especially diamond drilling, in undeveloped areas of the mine. 3. Contributions to the understanding of the general geology of the deposit and its regional setting, including ore genesis, structure, and mineral relationships. Magma Ore Deposit The east-west trending Magma vein, dipping about 70" south, cuts through a 6000-ft thickness of concordant limestones, quartzites, shale, diabase, and schist, named in descending order. These

Jan 1, 1949

By J. T. Raleigh, D. L. Flock

This study investigated the nature of formation plugging with bacteria and attempted to relate its characteristics to physical rock properties. Fifteen core samples of four specific formation types were defined and plugged using a commonly occurring, uniform sized dead bacteria, Bacillus subtilis. Two of the formation types were fairly uniform-grained sandstones and two were heterogeneous carbonates. The injection rate and concentration of solids in the brine were held constant during the test runs. The pore geometry factor G was a significant petro-physical rock characteristic for correlation with depth of plugging, but lacked importance as a parameter for rate of plugging. Although the G factor may not completely describe porous rock geometry for plugging predictions, for reservoirs with multi-pore systems, there is evidence that the pore geometry factor might form a basis for establishing injection water specification in more llornogeneous reservoirs with only primary porosity development. INTRODUCTION GENERAL PURPOSE Injecting water into oil-bearing formations to increase recovery is common practice in the petroleum industry. One of the most serious operational problems involved with water injection wells is the tendency of the porous rock immediately adjacent to the injection wellbore to plug partially. This results in increased injection pressures and/or a decrease in the rate of injection. This plugging in injection wells can result from a number of causes, including bacteria contained in the injected water.1 The purpose of this work was to investigate the nature of injection plugging with bacteria and to attempt to relate its characteristics to physical rock properties. Many variables exist in research of this type, so, to reduce them, injection rate and concentration of bacteria in brine were held constant. The bacteria used for plugging was a uniform-sized, dead bacteria, Bacillus subtilis, a micro-organism commonly found in water, air and soils. Four specific porous rock types were plugged—two consolidated sandstones and two heterogeneous carbonates. The experimental work involved two distinct phases. The first concerned determining the physical rock properties and the second was the experimental work of actually plugging the selected core samples. PORE GEOMETRY FACTOR Capillary pressure is necessary to displace a wetting fluid from a capillary opening with a nonwetting fluid. The factors which govern capillary pressure are the surface or interfacial tension of the fluids involved, the system wettability and the equivalent pore radius. Thus: P,= 2ucososrd..........(1) Thomeer used the idea that the location and shape of the capillary pressure curve reflect characteristics of the pore structure of any porous media sample.' He presented the mathematical description of capillary pressure curves and of indicated differences in pore geometry of samples. where G = pore geometry factor PC = capillary pressure Pi = displacement pressure (V,)p, = fractional bulk volume occupied by the displacing fluid at any capillary pressure (V,), = fractional bulk volume occupied by the displacing fluid at infinite pressure or total interconnected pore volumes. The shape of the curve is defined by the pore geometry factor G. The curve shape is related directly to the sorting and interconnection of the pores of the sample. The location of an infinite number of curves can be defined by the same asymptotes. However, these curves differ in shape, each curve being described by a specific value of G. Thus, the description of a curve is unique when, in addition to the position of its asymptotes, its shape is defined. These curves can be used graphically to determine the characteristic parameters of any arbitrarily located curve. Those parameters that can be approximated from any capillary pressure curve are: (1) total interconnected pore volume, represented by (V,),- ; (2) extrapolated displacement pressure, the abscissa axis; and (3) pore geometry factor, by the curve shape. PROPERTIES OF BRINE AND BACTERIA The fluid used throughout this study was an aqueous solution of sodium chloride, 25,000 ppm by weight. The addition of salt to fresh water was intended to eliminate clay swelling in the sandstone cores and to retard leaching in the limestone cores. The viscosity of the brine solution at 100F, the temp-

Jan 1, 1966

By B. J. Steblay

Roof bolts are the primary means of supplemental support in coal mines and are widely used in other mines. Presently, post installation loads are measured infrequently on only about 10% of the bolts by using standard torque wrenches that limit accuracy to about ± 30%. Because mine roof bolts are long, slender, non-uniformly sized, roughly forged, placed in a difficult environment, and subject to severe bending on installation, researchers have been unable to use ultrasonic reflection techniques to measure strain. A complete measurement system has now been assembled by the US Bureau of Mines, Denver Research Center. Obstacles such as bolt preparation, transducer mounting, reliable reflection, and calibration have been dealt with. The seemingly simple concept of measuring the time of flight of an ultrasonic pulse to a reflector is actually complex due to the need to measure to 0.0025 mm (0.0001 in.) accuracy, the sensitivity of velocity to temperature, and stress, and the stability required to make measurements over several years.

Jan 1, 1986

By J. R. Ross, J. B. Rosenbaum

Bureau of Mines research has resulted in the development of fluid- bed ion-exchange columns for recovering uranium from slime pulps. In pilot plant tests, slime slurries containing up to 6 percent solids were processed at flow rates of 10 gallons per square foot per minute with high uranium recoveries and efficient resin loadings. Uranium was effectively eluted in a laboratory fluid-bed elution column at eluate-to-resin ratios of less than 5:1 and eluate flow rates of 3 gallons per square foot per minute. Construction costs of mills using these improved ion exchange techniques are estimated to be 25 percent less than for mills using solvent extraction of clear solutions. For mills having a capacity of 2,000 to 2,500 tons of ore per day, the saving would be in the range of $2.5 million. In addition, a saving of about $0.80 per ton of ore in total operating costs is indicated.

Jan 1, 1973

By Charles M. Cooley

With explosives representing over 10 pct of the cost of operating the entire company, the Maumee Collieries Co., Terre Haute, Ind., inaugurated a program to develop a low-cost blasting agent. Results of more than two years' work were announced on May 1 by Hugh B. Lee, president of the company. Utilizing a mixture of commercial-grade ammonium nitrate and carbon black packed in polyethylene bags, Maumee has been able to reduce blasting costs by 50 pct. The lower costs are brought about principally by elimination of high transportation charges on fixed explosives and use of low-cost material (commercial NH,NO, and carbon black). The Akremite blasting method incorporates a 20-lb cap-sensitive primer to detonate the stable explosive. Maumee now uses Akremite exclusively in its stripping operations producing more than 2 million tons of coal per year. The explosive is employed to break about 25 million cu yd of overburden that covers the coal

Jan 5, 1955

By David H. Browne

Nickel has always been a fruitful mother of problems. Previous to the year 1906 nickel was regarded as an element replacing iron in copper-mattes, and it was believed that the same laws which governed the elimination of iron could be applied to nickel. This conception has lately undergone a complete change, and nickel in all its stages is now regarded as an element replacing copper; in other words, copper-nickel is considered not as two elements, but as one metal. When we commenced our investigations on Monel metal we made a great many experiment* on the conversion of mattes, both high copper and high nickel. We studied closely the composition of the mattes and the changes produced by the blow. We found in all cases certain agreements which me believe are due to some law. Briefly stated, our conclusions are as follows : 1. Nickel is not an element replacing iron in matte. 2. Nickel-copper alloys act in the matte-blow like one metal. 3. Nickel-copper alloys follow, during the matte-blow, exactly the same laws that govern the behavior of copper alone. This brings up the question: What are the laws governing the production of metallic copper, and what are the relations of copper to sulphur and iron during the Bessemer blow?

Jan 1, 1911

By Stanley Arnot

THE Mother Lode district in California is probably better known as the land of Bret Harte and Mark Twain than as a gold-producing district, although in this respect it holds an important place. The history of . quartz mining on the Mother Lode dates back to the '50s, when, after the first fever of the gold rush, men began to look for something more permanent, if not more lucrative, than the placers. Since that time,: the discoveries, shutdowns, and reopenings of the many mines, together, with the varying fortunes of their numerous operators, constitute an: interesting chapter in California history, but one too long to include in a description of mining methods. The district is well situated, so far as physical conditions are concerned. The Mother Lode extends along the western slope of the Sierra . Nevada Mountains, about half way between the crest and the Sacramento and San Joaquin Valleys, the country traversed consisting of low rolling hills-typical foot-hills. The elevation varies from 1000 to 1800 ft. and the climate is most desirable. There is an abundance of water, timber is easily obtained from the higher foot-hills a few miles east, and: cheap hydro-electric power is generated practically on the Lode. These natural conditions are conducive to low costs in mining and have been the deciding factor in allowing profitable exploitation of the comparatively low-grade orebodies. Transportation facilities are, not bad. Five branch railroads, from the main trunk lines in the valley, tap the district at intervals of from 10 to 30 miles, the roads connecting these are fairly good for trucking purposes. Labor is made up of several nationalities, the principal ones being American, Spanish, Jugo-Slav, Italian, and Mexican. There were few Mexicans on the Lode prior to 1919, but the shortage of labor, experienced generally by the mining camps of the country in the years following the war, made necessary the hiring of some. The percentage of Mexican labor rapidly increased in 1920 and for a year or so thereafter, but it has now diminished until at most of the mines only a few Mexicans are working. Of the different nationalities, Americans are the most efficient and Mexicans the least.

Jan 9, 1925

By Be Van Presley

There has been developed at Latouche a rather unusual system of mining which, for want of a better name, has been called the "Latouche system of mining." It is a modified form of shrinkage stoping applicable to orebodies of large or fairly large size where the ground is such that timbering would not be required in stoping. Mention has been made of this method of mining by Birchll who gave no details as it had been in use only a short time and the final outcome undetermined. The system, however, has proved to be entirely successful and it is thought that a paper covering it might be of general interest. Before proceeding with a detailed description of the Latouche system a brief description of the property and the various mining methods previously used will be given. Location The Beatson mine of the Kennecott Copper Corpn. is situated on the west coast of Latouche Island, in Prince William Sound, Southwestern Alaska, 45 miles east of Seward, the coast terminus of the U. S. Government Railroad. It is a regular port of call for ships on the Southwestern Alaska run. The island is about 12 miles long and 3 miles wide. A ridge of mountains runs the entire length with a maximum elevation of 2500 feet. Climate Latouche has to contend with possibly the greatest amount of precipitation on the North American continent. The annual average precipitation for the past 4 years has been 188 in., with 248 in. for the year 1926. A rainfall of 4 in. per day is not uncommon. In the winter the thermometer rarely falls below +20° F. and the snowfall is usually heavy during the months of March and April.

Jan 1, 1928

By James W. Shaffer

Aluminum is the most abundant metallic element of the earth's crust and is a constituent of nearly every type of rock (Clark, 1924, p. 13). The sources of aluminum and aluminous material most commonly used by modern industry are the bauxitic raw materials consisting of bauxite, bauxitic clay, and aluminous laterites. These are mixtures of hydrated aluminum oxide minerals and mineral impurities. End Uses Bauxite is used as an aluminum ore and in the manufacture of refractory products, aluminous chemicals, and abrasives. Other raw materials are used for aluminum ores, but their use is minor compared to bauxite. Refractory products made from bauxite are synthetic mullite, high-alumina fire bricks, castables, monoliths, cements, and ramming mixes used by the iron, steel, and cement industries. Chemicals made from bauxite are aluminum sulfate and sodium aluminate for water treatment and aluminum chloride used in refining crude petroleum. Among the abrasive products made from bauxite are coated abrasives, sharpening stones, and grinding wheels. Special grades of bauxite are used in the decolorization and clarification of raw sugar and lubricating oils. Bauxite has been used for road surfacing but mainly because other material was not more readily available. Perhaps the oldest use of bauxite and aluminous laterite is for a building stone. Ancient temples and more recent structures in India have been made from these and some varieties are suitable for decorative stone. Geology Mineralogy and Properties – Bauxite is a mineral raw material composed principally of one or more hydrated aluminum oxide minerals and impurities of silica, iron oxide, titania and elements in minor or trace amounts. The hydrated aluminum oxide minerals are gibbsite, boehmite and diaspore. Corundum is not included as a bauxite mineral although it does occur in some bauxite deposits. Boehmite and diaspore are both alumina mono-hydrates and have essentially the same composition, but diaspore has a greater hardness and a higher specific gravity because of a more tightly bonded and compacted atomic structure. Gibbsite is an alumina trihydrate mineral. Properties of bauxite minerals are shown in [Table 1].

Jan 1, 1975

By E. S. Machlin, Morris Cohen

GRENINGER and Troiano' were the first to establish the fact that the habit planes of mar-tensitic products are usually planes of high indices. In steels containing 0.55 to 1.4 pct C, the habit plane indices are {225}A.* In steels with more than 1.5 pct C and in Fe-Ni alloys, the indices are {259In. The presence of both habits in certain alloy steels has been reported recently." Several investigators"-" have subsequently attempted to provide an understanding of these complex habit relations. Bowles'6 work is the most recent and the most successful. Like Greninger and Troiano, Bowles concluded that the transformation occurs in two steps, the first, a strain (or displacement) that is homogeneous throughout the volume of the martensitic plate, while the second is a strain that is homogeneous only within relatively small portions of the martensitic plate. The first strain yields the measured tilt of the specimen surface, but does not produce the final martensitic structure. This and the correct lattice orientations are achieved by the second strain. Bowles also reasoned that each strain could be described by the motion of a plane of no rotation and no distortion (hereinafter called the invariant plane) in a direction not necessarily contained in the plane.** In applying these considerations to steels with {225}a habits, Bowles found that the habit plane coincided with the invariant plane of the first strain, a result which signified that the atoms move along certain paths during the transformation. Whether this correlation results from the existence of some sort of a plate nucleus6 lying along the invariant plane of the first strain, or whether the invariant plane primarily defines the preferred directions of propagation of the first strain, will be discussed in a later section. There are two obstacles to the general acceptance of Bowles' treatment: 1—it has not been shown that elements of his double-strain analysis are unique, and 2—it is not known whether his treatment applies to transformations yielding the {2591A habit. Unless these two questions are resolved, the correlation between the habit and invariant planes in the {225}A systems might be regarded as coincidental. Experimental Procedure Using a 70 pct Fe-30 pct Ni alloy as an example of a {2591A habit system, preliminary attempts were made to obtain a double-strain solution based on a Nishiyamax** set of orientation relations and on a Greninger-Troianot set, adopting the stereographic technique described by Bowles" who used the Kurd-jumow-Sachstt set in connection with the {225}A habit. These attempts were unsuccessful because the method is essentially one of trial and error and requires either exceedingly good luck or a prior knowledge of the results being sought. Consequently it was decided to measure independently the strain associated with the formation of a martensitic plate as well as the habit-plane indices of the particular plate. By means of matrix algebra, the measured strain was applied to the austenite lattice, whose orientation with respect to the strain was determined, in order to ascertain whether the resultant structure would have the lattice of martensite. This was not found to be the case, and hence it was assumed that the measured strain was the first of two Bowles-type strains, characterized by the motion of an invariant plane. A solution of this displacement was obtained in terms of the invariant-plane indices and the direction of motion of the atoms. Then the second strain

Jan 1, 1952

Discussion of the paper of L. O. HOWARD, presented at the Salt Lake meeting, August, 1914, and printed in Bulletin No. 91, July, 1914, pp. 1785 to 1790. E. P. MATHEWSON, Anaconda, Mont.-I would like to add a few words of praise on Mr. Howard's work at the Old Dominion. Mr. Howard has given this particular converter shell his personal attention, and the results are shown in the figures given. Similar converter shells, a little different in shape and of about the same size, have been tried in many plants throughout the United States. The results have been highly satisfactory, but there is no shell of the size of the one described by Mr. Howard that has given anything like the results that Mr. Howard's shell has given. I know of larger shells that have given very good service, and are still in operation, and require very little repair. The main thing about the whole process of using the basic lining in copper converting is to keep the temperature within reasonable bounds, particularly not to get the furnace too hot. If it is overheated a little bit, for say half an hour, an entire lining may be ruined. It is very easy to keep the temperature regulated 'if the mass is large. If you have a large mass in your converter you can easily prevent it from getting over-heated, and that is the big argument in favor of the extra large converters. Of course, there is a limit to what a plant can turn out in the way of matte. Very few plants can supply matte sufficient to keep a converter of 20 ft. in diameter in operation constantly, but the 20-ft. converter is very much superior to the 12-ft. converter in easy handling and absolute control of the temperature. I think Mr. Howard is to be congratulated on the excellent showing he has made.

Jan 12, 1914

By I. W. Alcorn

THE cost of drilling in the past few years of proration and ever decreasing allowables has received increasing thought and study. It seems to parallel the strides made with respect to pumping problems in 1932 and 1933. Low profit margins stimulate the search for economies. Any discussion of slim-hole drilling involves a multitude of abstract values, and the problem can be attacked only by a study of records and rational thinking. In a measure, traditional methods must be studied with a questioning attitude. The words "slim hole" may be somewhat misleading, as the term is entirely relative. For that reason I wish to define it as used in this discussion. On the Gulf Coast, I would define a normal hole as one in which 10 3/4-in. surface casing has been set and below which a 9 7/8-in. hole is dug. With this as a datum, holes of larger diameter below surface would be called "large holes," with 12 1/4 in. as the "extra large" class and holes of smaller diameter classed in the slim-hole range, 6 1/4 in. representing about the minimum size. The optimum size has not been definitely determined, but the preference is for a program that would call for setting 8 5/8-in. surface casing and digging a 7 3/4-in. hole. Different sections of the country might very properly deviate from this practice because of differences in depth, formations, regulations, or other factors. This paper will be confined to a discussion of the drilling of exploratory wells, as the drilling of this class of wells is quite a different problem from that of drilling a proven field, although many of the same considerations apply in both cases, as will be apparent. Although for many years shallow slim-hole and core-test holes of small diameter had been dug, it was not, I believe, until the fall of 1937 that serious consideration was given to its application in drilling wells 7000 ft., 8000 ft. and 9000 ft. deep on the Gulf Coast. This does not mean that nearly all such wells drilled on the Gulf Coast now are of the slim-hole variety, but only that efforts have been aimed in that direction with very encouraging results and there has been a very definite trend to reduce the size of holes, a trend that probably will continue. As to exploration policy, there appear to be two distinct and opposite views. The one usually followed in the past was more or less designed to "shoot the works" on one well. Generally on the Gulf Coast, the depth at which production might be obtained is limited by the drilling equipment and economics. With this thought in mind, wildcat wells are often planned with the idea of carrying the depth to 10,000 ft., or even 15,000 ft. All of the possible hazards are anticipated and the general drilling and casing programs are so predicated. Such wells contemplate the drilling of large-diameter holes; the setting of at least one protective string of casing and an extensive coring policy, all of which finally adds up to an expensive well. As opposed to this general policy is the slim hole. This, on the Gulf Coast, recognizes that new discoveries represent gam-

Jan 1, 1941

By S. M. Moos, R. E. Dugger

In reviewing available vacuum filtration equipment in this paper, several types of filters have been included which are probably not familiar to operators in the mining industry. However, it was felt that these units might be of interest in the event that an application should arise for the filtration of a product in the future that does not exist today. In addition, exposure of our industry to equipment used in other industries might have a tendency to be thought provoking and perhaps lead to the development of equipment and/or applications in our industry which do not necessarily exist at this time. Most innovations in filtration equipment have been confined to the improvement or design change of components and accessories, particularly reflecting the availability of materials of construction that have been developed. Recent developments in the application of horizontal belt filters have been innovative. The application of this unit as a substitute for or an adjunct to thickeners in a CCD circuit can certainly be innovative and perhaps provide a basis for reduction in capital and operating costs in this area. For example, mill tails are generally pumped at the highest possible density that will adequately flow. Tailings ponds and dams with their attendant design requirements are based upon this estimated water volume. Availability of a much dryer, non-flowing filter cake opens up several new options for disposal. Considerable cost savings could result in the design and planning of disposal areas for containing dryer material. No attempt has been made in this paper to provide a manual for the operation of all of the many types of equipment that are available. Rather, the paper tries to present an overview. Fundamentals of Vacuum Filtration Filtration may be defined as the separation of solids from a liquid effected by passing the liquids through a porous medium. If the filtrate is induced to flow through the medium by hydrostatic head, we refer to it as gravity filtration. If we utilize super-atmospheric pressure upstream of the medium we call it pressure filtration and if sub-atmospheric pressure is applied downstream of the medium we call it vacuum filtration. Centrifugal filtration occurs when a centrifugal force is applied across the medium. Centrifuges will not be discussed in this paper. The process goal of filtration may be the production of dry solids where the cake is the valuable product, clarified liquid

Jan 1, 1980

By P. Ramachandrarao, T. R. Anantharaman

EVER since the technique of quenching metals and alloys from the melt (splat cooling) was perfected a decade ago, it has been recognized that the grain size of products solidified by this technique may be extremely small.' The further observation that fcc metals quenched from the liquid state contain very few dislocations has led to the inference2 that metals are subjected to negligible or no stresses during the rapid solidification characteristic of the "gun" or "piston-and-anvil" technique. Evidence for the incidence of appreciable densities of stacking faults has, however, been obtained in case of some splat-cooled fcc and hcp alloys,3 although not for pure metals. In the light of these earlier observations it was considered desirable to study X-ray line-broadening effects, if any, in fcc metals rapidly cooled from the melt. In the present work pure silver (>99.99 pct), aluminum (>99.99 pct) and lead (>99.9 pct) were quenched from the liquid state from temperatures about 50°C above the melting point by the "gun technique" and the resulting foils were subjected to X-ray examination in a Philips Diffractometer. The quenched foils (up to -10 u thick) did not generally stick to the substrate surface and could be easily transferred to the Diffractometer without introducing any plastic deformation. The profiles of the first five reflections from the foils were recorded in each case with Cu Ka, radiation at the slowest available scanning speed of 1/8 deg per min. To correct for instrumental broadening, profiles were also recorded from the metals annealed in vacuo at suitable temperatures. The integral breadths of the X-ray reflections were arrived at by a procedure described earlier.' There was a distinct suggestion of preferred orientation in the recorded intensities of reflections from aluminum and lead foils. Such an effect was not observed in case of silver. In addition, the integral breadths of X-ray reflections from splat-cooled aluminum and lead were not significantly different from those recorded for the annealed metals. The analysis was therefore continued only for silver where the X-ray line broadening was appreciable. The pure diffraction broadening, B, was evaluated for each X-ray reflection (hkl) from silver from the observed, B, and instrumental, b, breadths with the aid of each of the three equations due to Scherrer,5 Anantharaman and Christian,6 and Warren and Biscoe,7 respectively: Bs= B-b BAC=B- b2/B Table I gives the values of particle size, 71, the lattice strain, E, arrived at by the use of the following well-known relations and on the assumption that all observed diffraction broadening could be attributed to lattice strain or particle size, respectively: E = 1/4 cos ? n= B cos ? where A is the wavelength of X-radiation and 0 is the Bragg angle. As no significant peak shifts or asymmetry could be detected in the profiles from the foils, the possibility of any significant contribution due to twins or stacking faults was ruled out. The absence of faults is by no means surprising since pure silver is known to develop stacking faults only on severe deformation and the stacking fault densities recorded so far for even silver filings have been extremely low.' The very low values for percentage mean deviation from the mean value for the particle size in Table I strongly suggest that all observed broadening in splat-cooled silver can be attributed only to small particle size. This conclusion receives further support from the lowest mean deviation recorded for data computed from the Scherrer equation based on Cauchy profiles that are considered characteristic of particle size broadening. Further analysis for separation of particle size and lattice strain effects was considered unnecessary in view of the very large mean deviations obtained for strain values and also the earlier results suggesting absence of even detectable strain in metals and alloys quenched from the melt. It is to be stressed in this connection that the particles are actually grains and not cells formed by walls of high dislocation density usually encountered in deformed samples. As such, the absence of strains is not surprising. The present results are probably the first to record X-ray line broadening due only to small particle

Jan 1, 1970

By Burnham E. Field

The chemical industry is constantly looking for new materials which either are more resistant to corrosion than those now available or have improved physical properties to meet the requirements of higher temperatures and greater pressures. Attack by acids is one of the more important forms of corrosion and in the last few years the development of acid-resistant alloys has been quite rapid. Perhaps the most notable example is that of nitric acid, the problem of which has largely been solved by the chromium-iron and chromium-iron-nickel alloys. Sulfuric acid may be handled in lead, iron, or the iron-silicon alloys, depending on conditions. As to hydrochloric acid, no metal or alloy can be called entirely satisfactory for handling this acid under plant conditions.' The results of our investigations on the resistance of the nickel-molybdenum alloys to hydrochloric acid have been confirmed by those of Guertler, Rohn, Schulz, Jenge, and others12 but thus far only one such alloy has approached commercial production in Germany; this contains approximately 15 per cent. chromium and 7 per cent. molybdenum with the remainder chiefly nickel. Dr. S. W. Parr, as far back as 1914, developed a complex alloy known as "illium," with a nickel base and containing some molybdenum. 3 Dr. Parr was primarily interested in an alloy for lining bomb calorimeters, and while illium does show good resistance to acid it is too expensive for general use. Two United States

Jan 1, 1929

By Burnham E. Field

The chemical industry is constantly looking for new materials which either are more resistant to corrosion than those now available or have improved physical properties to meet the requirements of higher temperatures and greater pressures. Attack by acids is one of the more important forms of corrosion and in the last few years the development of acid-resistant alloys has been quite rapid. Perhaps the most notable example is that of nitric acid, the problem of which has largely been solved by the chromium-iron and chromium-iron-nickel alloys. Sulfuric acid may be handled in lead, iron, or the iron-silicon alloys, depending on conditions. As to hydrochloric acid, no metal or alloy can be called entirely satisfactory for handling this acid under plant conditions.' The results of our investigations on the resistance of the nickel-molybdenum alloys to hydrochloric acid have been confirmed by those of Guertler, Rohn, Schulz, Jenge, and others12 but thus far only one such alloy has approached commercial production in Germany; this contains approximately 15 per cent. chromium and 7 per cent. molybdenum with the remainder chiefly nickel. Dr. S. W. Parr, as far back as 1914, developed a complex alloy known as "illium," with a nickel base and containing some molybdenum. 3 Dr. Parr was primarily interested in an alloy for lining bomb calorimeters, and while illium does show good resistance to acid it is too expensive for general use. Two United States

Jan 1, 1929

By William M. Kester

INTRODUCTION The Coal Research Bureau of the School of Mines at West Virginia University is presently conducting laboratory-scale tests to determine the technical feasibility of beneficiating pulverized coal and coal fines with high-intensity electromagnetic fields. Interest in magnetic processes for cleaning fine coals was stimulated by results obtained by Yurovsky, et a1 in 1958.1 This work, while not new in concept,2,3 indicated that pulverized coal which had been thermally treated in a rotary drum in the presence of superheated steam and air underwent thermo- chemical reactions. Films of the ferromagnetic minerals magnetite (Fe2O3), hematite (Fe3O4), and pyrrhotite (FeS[3]) were reported to be formed on the surfaces of the pyrite grains associated with fine coal during the foregoing treatment at temperatures ranging from 120 to 360°C. After thermal treatment the coal was magnetically separated in an experimental magnetic device having a field strength of 10,000 oersteds.

Jan 5, 1965