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By Nicholas J. Grant, Rolf Nordheim, Thomas B. King

Constant-load creep-rupture tests were conducted in an argon atmosphere at temperatures of 1600 to 2200°F on two heats of iron containing about 0.06 and 0.09 pct P in solid solution. The tests were conducted in the as-cast condition. Stresses were selected to give strain rates approaching those encountered in the hot working of steel, and within the limits of the creep-rupture test apparatus, namely. from about 0.001 to 50 pct per sec. FOR generations, rolling and forging practices have been developed largely by empirical methods, based on prior experience. While largely successful, difficulties are frequently encountered when new or different alloy compositions are tried for the first time. There is need to know the relationships which exist among temperature, strain rate, composition, and other variables on the deformation and fracture characteristics of steels. It has been shown for aluminum and several high-temperature alloys that the deformation and fracture characteristics follow rather well-defined laws and patterns which are closely related to the effects of strain rate, temperature, and composition.1"3 As the melting temperature of aluminum or its alloys was approached, it was possible to study the interplay of work-hardening factors and recovery or recrystal-lization, the latter resulting in improved ductility and increased resistance to intercrystalline fracture. In particular, the effects of composition are very poorly known. Within the meaning of "composition" should be included impurity elements, such as sulfur, phosphorous, lead, copper, and many others, as well as those elements which are added for alloying purposes in iron. The role of multiphase structures, in contrast to solid solutions, should also be studied in much greater detail. high strain rate creep-rupture tests would provide information regarding the deformation and fracture characteristics of metals at hot-working temperatures. It was also desired to establish the stresses which are necessary to accomplish the desired deformation, and to relate these to the strain rate and temperature. Secondly, it was the purpose of this particular study to determine the effects of phosphorus, within solid solution limits, on the deformation and fracture characteristics of iron at hot-working temperatures. EXPERIMENTAL PROCEDURE Two phosphorus levels were selected, one corresponding to the upper limit normally found for commercial steels, and one substantially higher than this, but within the region of solid solubility at the test temperatures chosen for this investigation. Twenty-pound heats were prepared by induction melting electrolytic iron in air in a magnesia lined furnace. After deoxidation with about 0.2 pct Al, ferro-phosphorus was added, and the heats were then poured into prefired silica molds. The purpose of using silica molds was to obtain a slow cooling rate during solidification to produce a relatively coarse grain size, producing a structure subject to some segregation and therefore more nearly characteristic of ingot structures. The major part of the casting assembly provided a large shrinkage head in order to produce sound castings and to promote slow cooling of the specimens. The primary austenitic grain size varied from ASTM No. 2 to No. 00. The composition of the heats, including a low phorphorus melt, used for comparison purposes, is shown in Table I. It will be noted that the oxygen content of the phosphorus containing heats is relatively high, in spite of the deoxidation practice, a condition which is difficult to control in small melts. Creep-rupture tests were nevertheless undertaken when it was noted that this quantity of oxygen did not appear to give results any different from those from a heat containing 0.01 pct 0, low phosphorus and comparable carbon Content;4 see Table 11.

Jan 1, 1961

By A. G. Preban, R. J. De Angelis, J. B. Cohen, P. Gordon, D. C. Brillhart

Changes in stored energy, resistivity, density, X-ray line broadening, and dislocation arrangements (from transmission electron microscopy) have been mensured on copper specimens shock-loaded at 75 to 435 kbars. The stored energy in shock-loaded copper and changes in density and resistivity are larger than those after conventional deformation. A high density of twins makes an appreciable contribution to all the measured quantities. Dislocation densities rise to values of 1011 lines per sq cm at the highest pressure. The resistivity, density, and X-ray In a study of the effects of shock loading on copper, changes in stored energy, resistivity, density, hardness, lattice parameter, line broadening, and dislocation structure have been examined after subsequent annealing of specimens shocked to various pressures. This paper presents certain aspects of the data, taken by two groups, one at the Illinois Institute of Technology, and the other at Northwestern University, and compares the changes in these properties, and what they indicate about the effects of shock deformation. measurements yield dislocation densities in substantial agreement at all pressures, after correcting for the effects due to the twins. At the higher pressures, electron microscopy yields dislocation densities that are lower by a factor of about 5 to 10. Dislocation densities from stored -energy measurements are high; this finding can be rationalized by the consideration that the deformation twin boundaries present are largely incoherent. There is no evidence for homogeneous dislocation nucleation during shock loading. Shock loading any metal or alloy, such as copper, causes a large increase in yield strength, with dimensional changes of the order of only a few percent."' Other properties have not been extensively studied, but this result clearly indicates the importance of examining the substructure. Previous studies of the substructure of conventionally deformed specimens have been made using electron microscopy,3-6 X-ray diffraction,7,8 and etch pitting.9,10 The dislocation density can reach values of about 10" per sq cm; and the dislocations are arranged in cells approximately 0.15 in size. The substructure varies widely, however, from point to point in the specimen. The substructure of explosively loaded copper consists of cells of about the same dimensions6,11 but their size is more uniform.6 Profuse twinning occurs12,13 and the twins are often too small to be detected optically.6,13 The boundaries outlining these twins appear to be incoherent.14 There is now ample evidence 13-15 that twinning is a strengthening mechanism in fcc metals but this is only part of the strengthening effect in shock-loaded copper.* From the twinning systems which operate in shock-loaded single crystals,13 and from changes in texture on shock loading,17 it has been shown that both the

Jan 1, 1968

By C. M. Fellman

THE over-all picture of safety in mining has been encouraging during the past few years, and in mining activities as a whole the trend in accident occurrence is downward. This is the more noteworthy when the type of labor used in mines during the war period is taken into consideration. The drafting of young mining employees into the armed services and the departure of others for work in other war industries took a heavy toll of young, husky, active men. Their places were taken in large part by older men who returned to the mines, or by inexperienced men with little if any knowledge of mining. Despite the lack of labor and especially of skilled labor, and the difficulty of obtaining new equipment as well as maintaining and replacing worn or broken equipment, and numerous other difficulties the mining industry not only reached and maintained maximum production but made the increase with little if any sacrifice of safety. In fact, in many instances better safety records were. established than in normal

Jan 1, 1946

By F. R. Archibald, C. M. Nicholson

The present paper may be considered complementary to an earlier contribution on the same subject by F. R. Archibald and C. F. Jackson.1 It is particularly concerned with engineering and technological aspects of the operations at the Harleyville Alumina Plant during its period of operation from January 1945 to July 1946. The plant was built for and operated by Ancor Corporation, at Harleyville, South Carolina, as part of the government sponsored wartime program related to alumina production from domestic raw materials. The main purpose of the program was to secure technical and engineering data, based on actual plant experience, that might serve as a foundation for large scale production of alumina from raw materials other than bauxite. The Harleyville plant was directed specifically to treatment of clays found in very extensive deposits in the Carolinas and Georgia using the lime-sinter process developed by Ancor Corporation. It is considered that the purpose stated above has been served and this paper is to record and discuss some of the more important findings. The main factor in location of the plant at Harleyville was the presence in that locality of a rather remarkable deposit of high calcium limestone. The clay mining operation was centered near Aiken, S. C., and although a rail haul of ninety miles was involved there were, at the time, factors favorable to the Harleyville location offsetting, in part, the cost of transportation of clay, There are, no doubt, locations in the general area where clay and limestone deposits may be found in closer proximity hut they had not been proven up when the project was undertaken. Availability of power from the Santee-Copper development whose high tension line skirted the Property; ready access to rail and highway transportation; the promise, realized in actuality, of ample supply of soft water; and availability of labor supply were other factors of importance. Moreover, the general area has the decided advantage, for this type of operation, of a mild climate. Construction was begun in August 1943, and although stopped for a time priding review of the general situation that fall, it was resumed, albeit with less urgency, and substantially completed by the end of 1944. The total capital cost was approximately $3,460,000 The first alumina was turned out in April 1945 and from then until the plant was closed down in July 1946, the operations followed a succession of periods of production alternating with periods in which minor alterations were made in conformity with experience. Steady improvement was made and at the time Operations were discontinued it was considered that experience and the necessary engineering were in shape for removal of the remaining bottlenecks and a somewhat major revision in one section of the plant. Unfortunately this could not be carried out and it was necessary to discontinue the

Jan 1, 1949

By M. L. Fuller

DURING the last several years many papers have appeared dealing with the structure of highly polished metal surfaces The awakening of interest in this subject is due to the applicability of the electron diffraction technique to the study of surfaces The original theory of Beilby1 considered the surface of polished metals as of the nature of a super-cooled liquid or a vitreous, amorphous solid The electron diffraction effects from polished metals have been interpreted by many to be a direct experimental proof of the correctness of the Beilby theory This interpretation has been strongly opposed by others, so that at the present time the subject is in an uncertain and controversial state In the present paper new, and hitherto unpublished, electron diffraction effects from polished zinc are described These observations indicate that the polished surface of zinc is crystalline PUBLISHED WORK Many papers2-10 have interpreted the electron diffraction evidence as proof of the Beilby amorphous theory All investigators agree that highly polished metals give rise to two diffuse diffraction haloes, similar to those obtained by the diffraction of X-rays in liquids and vitreous solids It is this similarity that leads to the amorphous-layer interpretation of polished metals Strangely, the interatomic distances calculated from these haloes are very similar for the various metals investigated, in spite of a rather wide range of such distances in the crystalline and liquid states The calculated atomic sizes are, furthermore, smaller than are experienced in the normal states of the metals In spite of these anomalies, the amorphous-layer interpretation has been adhered to by many One investigator, S Dobmski,11 differs from the others in his experimental results By polishing under benzene in order to avoid the possibility of oxidation, Dobinski obtains diffuse haloes of [radire] different from those previously obtained He thus obtains a more rational quantitative correlation of-the diffuse haloes with the amorphous-layer theory

Jan 1, 1938

H. M. HOWE, Bedford Hills, N. Y.-One wonders, whether it might not be well to check, by a rather simple and direct way, the inferences that would be drawn from this investigation. Suppose we quench, in these various liquids cylinders of steel, selecting material that is not likely to split in hardening, and then examine their cross-sections micro-scopically. If the cylinder is of any size, you will find a series of concentric bands, a very hard band, a softer band, and a hard band-but it seems that here would be a way of checking the inferences from the cooling curves by comparing these waves of hardness obtained in similar speci-mens quenched in different liquids. One would think that there would be great promise in that way. One's first thought is to quench similar pieces of steel, similarly heated, in different liquids and determine their hardness. I suppose many of us have tried that. We then meet the-difficulty that it is not the most rapid cooling that gives the greatest hardness. There is an intermediate rate of cooling that gives maximum hardness so that you can not by any simple method as that check this cooling method. But it seems possible

Jan 12, 1919

By Michel T. Halbouty

South Texas, one of the world's important oil and gas-producing areas, continued to hold interest during 1939 as another scries of new fields and new producing levels was developed within its boundaries at a fairly continuous rate throughout the year. There were 1801 wells drilled in this area in 1939, compared to 1678 in 1938; of these, 1515 were drilled in established fields, or as extensions to proven areas (semi-wildcat), and 286 were drilled as rank wildcats, in search of new production. Among these rank wildcats, 22 produced oil, 7 produced distillate and gas and 257 were abandoned as dry holes (see Table 5). Of the 1515 field and cxtension wells, 1213 produced oil, or distillate and gas, 50 produced only gas and 252 were dry; 38 found new productive sand levels in proven ficlds. Jim Wells County led this district in discoveries, having had 9 new fields arid 9 new productive sands found within its border during 1939. Most activc of the 1939 discoveries were Reynold?; and Ben Bolt fields in Jim Wells County and Minnie Bock field in Nueccs County; among producing fields the most activc were: East White Point and Aransas Pass (McCampbell). Production from South Texas in 1939 totaled 55,105,506 bbl. against a total of 56,152,122 bbl. produced in 1938. South Texas should continue its present rate of developrnent and exploration and this should result in the discovery of many fields in its numerous oil-bearing zones, and should also lead to more knowledge of the possibilities of its deeper horizons, such as the Mt. Selman and Wilcox formations; with the latter holding particular interest at the present time. Tide Water Associated Oil Company's A. M. Bruni No. I, Cole-Bruni field, Webb County, the deepest well drilled along the Mirando trend, was carried to 8959 ft., where it started to blow out from a Wilcox sand topped at 8954 ft., making gas, distillate and mud under heavy pressure. After the well was killed, drill stem beeame stuck and was cemented in place in order to test a Queen City (Mt. Selman) sand logged from 5620 to 5675 ft. This and other shows found in other wells along this trend, but out of this district, have served to increase the importance of this but little explored Sparta-Wilcox trend of South Texas during the year, and more activity along it is to be expected in the near future.

Jan 1, 1940

By Michel T. Halbouty

South Texas, one of the world's important oil and gas-producing areas, continued to hold interest during 1939 as another scries of new fields and new producing levels was developed within its boundaries at a fairly continuous rate throughout the year. There were 1801 wells drilled in this area in 1939, compared to 1678 in 1938; of these, 1515 were drilled in established fields, or as extensions to proven areas (semi-wildcat), and 286 were drilled as rank wildcats, in search of new production. Among these rank wildcats, 22 produced oil, 7 produced distillate and gas and 257 were abandoned as dry holes (see Table 5). Of the 1515 field and cxtension wells, 1213 produced oil, or distillate and gas, 50 produced only gas and 252 were dry; 38 found new productive sand levels in proven ficlds. Jim Wells County led this district in discoveries, having had 9 new fields arid 9 new productive sands found within its border during 1939. Most activc of the 1939 discoveries were Reynold?; and Ben Bolt fields in Jim Wells County and Minnie Bock field in Nueccs County; among producing fields the most activc were: East White Point and Aransas Pass (McCampbell). Production from South Texas in 1939 totaled 55,105,506 bbl. against a total of 56,152,122 bbl. produced in 1938. South Texas should continue its present rate of developrnent and exploration and this should result in the discovery of many fields in its numerous oil-bearing zones, and should also lead to more knowledge of the possibilities of its deeper horizons, such as the Mt. Selman and Wilcox formations; with the latter holding particular interest at the present time. Tide Water Associated Oil Company's A. M. Bruni No. I, Cole-Bruni field, Webb County, the deepest well drilled along the Mirando trend, was carried to 8959 ft., where it started to blow out from a Wilcox sand topped at 8954 ft., making gas, distillate and mud under heavy pressure. After the well was killed, drill stem beeame stuck and was cemented in place in order to test a Queen City (Mt. Selman) sand logged from 5620 to 5675 ft. This and other shows found in other wells along this trend, but out of this district, have served to increase the importance of this but little explored Sparta-Wilcox trend of South Texas during the year, and more activity along it is to be expected in the near future.

Jan 1, 1940

By G. M. Swinkels, A. Vizsolyi, E. Peters

A process is described utilizing ferric chloride leaching followed by reduction of the cupric content to cuprous by cement copper, with CuCl obtained thereafter by crystallization. The residual liquor is cemented with sponge iron to produce cement copper and a copper free ferrous chloride solution. The latter is oxidized in an autoclave with oxygen to regenerate ferric chloride and to precipitate excess iron as a granular, filterable hematite. Cuprous chloride crystals are reduced to high purity metal with hydrogen, while sulphur reports almost quantitatively in residues in the elemental form. Pyrite and molybdenite are not leached. This paper describes the important variables in the process, as well as the deportment of minor elements as silver, gold, selenium, tellurium, bismuth, nickel, lead, zinc, magnesium, etc. An elegant method of isolating silver from CuCl crystals is described, as well as recovery of gold from residues by a chloride reagent The process is described as non-polluting and capable of producing refined copper, ore grade iron oxide, elemental sulphur, and yields of minor metals as good or better than obtainable by conventional smelting, without the use of solvent extraction or electrochemistry.

Jan 1, 1981

The first of a series of special war meetings of the New York Section of the American Institute of Mining Engineers held on the evening of July 20 at the Machinery Club, preceded by an informal dinner. The subject for discussion was the important general one of the manganese supplies of the steel industry of the United States. It had been intended to include chromium supplies but this matter was crowded out and left for a later meeting. The principal speaker of the evening was Donnel F. Hewett of the U. S. Geological Survey, who, as a result of his recent studies of the resources of the country, ably presented the question of the extent to which the United States can furnish manganese ore.

Jan 9, 1917

By Charles Miller

Natural carbon dioxide has recently been exploited in the United States in consequence of oil and gas developments in the Western States and the growing demand by transcontinental and transoceanic shippers for solid carbon dioxide. The discovery by drilling of commercial deposits resulted in consideration of its geographic and geologic distribution and occurrence. Its wide distribution in nature is evidenced by its occurrence in the atmosphere, hydrosphere and lithosphere. The question of origin of carbon dioxide involves consideration of theories similar to those concerning natural hydrocarbons, although available evidence favors an inorganic rather than an organic source. Areas favorable to development of commercial production appear to be those in proximity to igneous rocks or in the vicinity of decadent volcanic activity, where, it has long been known, the gas is evolved either free or dissolved in the waters of fumaroles, geysers or mud pots. Structure contour maps are presented showing the Wagon Mound anticline in New Mcxico and the Farnham anticline, Utah. A well drilled on the latter supplies gas to a 20-ton plant manufacturing solid curbon dioxide at Wellington, Utah, on the Denver and Rio Grande R.R., whence it is shipped to surrounding territory and to the West Coast. Before funds are invested in a plant for the manufacture of liquid or solid carbon dioxide, whether supplied by wells or springs, an effort to ascertain the volume of gas available is advisable. The use of present methods of estimation of gas reserves with modifications to account for the quantity absorbed by any water present in the producing formation is recommended. The Farnham anticline is used as an example and computations are made of the probable volume of gas originally present in the structure. No attempt was made to compute reserves in the Niland area, California, for the reason that in such areas it is believed the volume is indeterminate. Introduction Carbon dioxide, in liquid and solid form, has found a wide variety of uses other than its primary application in carbonating beverages. It is now used in more than 40 different ways, ranging from cooling or freezing to use in gas or liquid form for mechanical purposes, chemical industry, explosive, fire extinction, and tire manufacturing. Undoubtedly the chief supply of carbon dioxide is obtained from industrial plants or artificial sources and until recently natural deposits of the gas have received little consideration. Few will question the utility and perhaps dependability of artificial sources, which possess the advantage over

Jan 1, 1938

By Charles Miller

Natural carbon dioxide has recently been exploited in the United States in consequence of oil and gas developments in the Western States and the growing demand by transcontinental and transoceanic shippers for solid carbon dioxide. The discovery by drilling of commercial deposits resulted in consideration of its geographic and geologic distribution and occurrence. Its wide distribution in nature is evidenced by its occurrence in the atmosphere, hydrosphere and lithosphere. The question of origin of carbon dioxide involves consideration of theories similar to those concerning natural hydrocarbons, although available evidence favors an inorganic rather than an organic source. Areas favorable to development of commercial production appear to be those in proximity to igneous rocks or in the vicinity of decadent volcanic activity, where, it has long been known, the gas is evolved either free or dissolved in the waters of fumaroles, geysers or mud pots. Structure contour maps are presented showing the Wagon Mound anticline in New Mcxico and the Farnham anticline, Utah. A well drilled on the latter supplies gas to a 20-ton plant manufacturing solid curbon dioxide at Wellington, Utah, on the Denver and Rio Grande R.R., whence it is shipped to surrounding territory and to the West Coast. Before funds are invested in a plant for the manufacture of liquid or solid carbon dioxide, whether supplied by wells or springs, an effort to ascertain the volume of gas available is advisable. The use of present methods of estimation of gas reserves with modifications to account for the quantity absorbed by any water present in the producing formation is recommended. The Farnham anticline is used as an example and computations are made of the probable volume of gas originally present in the structure. No attempt was made to compute reserves in the Niland area, California, for the reason that in such areas it is believed the volume is indeterminate. Introduction Carbon dioxide, in liquid and solid form, has found a wide variety of uses other than its primary application in carbonating beverages. It is now used in more than 40 different ways, ranging from cooling or freezing to use in gas or liquid form for mechanical purposes, chemical industry, explosive, fire extinction, and tire manufacturing. Undoubtedly the chief supply of carbon dioxide is obtained from industrial plants or artificial sources and until recently natural deposits of the gas have received little consideration. Few will question the utility and perhaps dependability of artificial sources, which possess the advantage over

Jan 1, 1938

By B. J. Harlan

The trying times experienced by the steel industry during the past four years have emphasized the necessity of producing pig iron at the lowest possible cost. The trend in both design and operation of blast furnaces has been toward this end rather than toward securing maximum production from a unit or group of units. In the following discussion the trend in design of stacks and auxiliary equipment will be taken up before operation is considered. Although few furnaces have been constructed in the past few years, the trend is definitely toward larger furnaces with a hearth diameter of 24 or 25 ft. Such a furnace is very flexible, being able to produce efficiently any desired daily tonnage between 500 and-1000 or more. The detail of the design of furnace stacks, with the exception of the top, has changed little in recent years. To decrease the velocity of gas through the throat of the furnaces, thereby reducing flue-dust losses, the stock-line areas are constantly being made larger. The top dimensions of the larger furnaces are usually as follows: Stock-line diameter, 19 to 20 ft.; large bell diameter, 14 to 15 ft.; straight section of throat, 5 to 10 ft. high; inwall batter, 1 to 11/4 in. Pe ft. The ratio between the area of the stock line and the area of the large. bell is usually about 1.85 to 1. The stock-line diameter of some smaller furnaces has been increased to that of the hearth diameter of the stack at the expense of the stack batter. Remarkable decreases in flue-dust production are claimed for the so-called " Venturi top," which is achieved by flaring the stock line, in the form of an inverted cone, from a diameter of 17 ft. at 10 ft. below the large bell closed to a diameter of 19 ft. 6 in. at 3 ft. below the large bell closed. Time alone will tell which of the two designs is the better. Because of differences in raw materials, one top may be better for some plants and the other top for other plants. In the search for lower costs and higher efficiencies all operators are, adopting stoves that will maintain maximum hot-blast temperatures with a minimum gas consumption. To meet these requirements, stove capacity of approximately 7 sq. ft. of heating surface and 1.8 cu. ft. of brick volume is required per cubic foot of wind blown per minute.

Jan 1, 1934

By J. C. Osler

The design of a tailings dam is a geotechnical engineering project of considerable scope. For the design, it is necessary to establish the engineering properties of the soil or rock strata which will support the dam and the tailings or other fill which will be used to construct the dam. The various field and laboratory investigations which are necessary to obtain the required design parameters are discussed in the paper and the use of these parameters to compute stability, settlement, and seepage are considered. The designer of a tailings dam can never assume an absolute knowledge of the properties of the foundation strata. Further, initial design assumptions are often approximate, particularly with regard to the distribution of pore pressures through and beneath the dam. Thus, the installation of performance monitoring instruments is recommended, since data obtained from such instrumentation can be used to check the stability of the structure both during construction and after its completion.

Jan 1, 1972

PRACTICAL PROBLEMS AND BASIC PRINCIPLES ranging from ore testing to cost estimation get a working over from top men in the minerals beneficiation field. The Minerals Beneficiation Division developed this symposium for presentation at the 1953 Los Angeles General Meeting to assist the many people who think that having a new plant necessitates a lot of trouble and dismay. The papers and free discussion from the floor give ways and means of approaching a new plant that will relieve the strain on the organization, if adequate attention is put on the program before work begins - that is if thought is given to the program itself, before tackling the actual mill design.

Jan 9, 1953

By Thomas Fraser

UP to the present, there has been no large coal-producing industry in any of the South American countries. Since colonial times, the great mineral and agricultural wealth of that continent has led the people to activities other than the development of manufacturing industries based on coal; and climatic conditions are such that there has been very little demand for solid domestic fuel. However, there are extensive and widely distributed reserves of coal in South America that would make the development of a modern coal industry feasible. That factor is of the utmost significance now, when it is believed that the South American countries are entering the pioneer phase of a broad industrial development. Coal Fields Great areas of coal-bearing formations of Cretaceous and Tertiary ages occur generally throughout the Andean uplift and extend into the coastal range of the Caribbean region far east of Caracas. Thus the west coast countries have adequate reserves of coal, which include a wide range of types and classes. In the eastern part of South America, east of the Cordillera, as in North America, the coal measures are of Carboniferous and Permocarboniferous ages. The principal known deposits in this area are in the southern States of Brazil. Permocarboniferous coals ranging in rank from lignitic to anthracitic are found in the States of Rio Grande do Sul, Santa Catarina, Parana and Sao Paulo. In the great.interior plateau of Brazil, south of the Amazon River, are extensive areas of Carboniferous strata that may contain coal deposits. There are widely scattered reports of findings of coal in' wells and stream beds in northern Piaui and Goias. In the Rio Fresco Valley, explorers have observed outcrops of two beds of anthracite and have brought to Rio de Janeiro samples from these beds. The Fresco is a tributary of the Xingu River that enters the Amazon from the south, but coal could not be shipped by water since the Rio Fresco area is in the upper part of the Xingu Valley, and there is a formidable series of rapids between that area and the lower level of the Amazon River basin. It is doubtful if coal deposits in this general area will be of economic importance for many years to come. Fig. 1 shows the general location of known coal fields of South America that have been explored sufficiently to indicate the presence of workable reserves. The coal deposits of the Andean region are similar in occurrence and general characteristics, as well as in age, to the coals of the Rocky Mountain region of North America. Although the coal fields obviously

Jan 1, 1952

By R. M. Rose, D. P. Ferriss, J. Wulff

Single crystals of tantalum, tungsten, and the binary alloys thereof were grown by electron-beam zone melting and tested in tension between 77° and 373°K. The ductile-to-brittle transition temperature increased sharply with solute concentration, for both tungsten-rich and tantalum-rich alloys; apparently, the maximum transition temperature exists near the 50 pet concentration. Twinning was observed to be a consequence of cleavage-crack propagation. Cleavage occurred on(100)planes, and extensive tearing and "river markings" were present. The onset of brittleness could not be associated with any change in deformation mode, the yield point phenomenon, or the large rise in yield stress with decreasing temperature. Cleavage was observed to initiate at either the specimen surface, or subgrain boundaries. The observation was made that the grain boundaries of Polycrystalline materials are probably even better as nucleation sites for fracture, and are responsible for brittleness at high temperatures and lower solute concentrations than those of the corresponding single crystals. TUNGSTEN and tantalum, the two high-melting neighbors in the third transition period of the periodic table, present striking contrasts. Although both are bee, tungsten has far higher elastic moduli, and the highest ductile-to-brittle transition (DBT) of all the pure metals.' Tantalum, however, is ductile at liquid helium temperatures. Large strain aging and yield point phenomena are observed in tantalum,2,3 but only to a lesser extent in tungsten.4 Tungsten work-hardens at a high rate,5 whereas this effect is negligible in tantalum.' Since the mutual solid solubility of these two metals is complete,7 and no ordering has yet been reported in the binary system, the possibility of depressing tungsten's DBT by tantalum additions was considered. Also, tungsten additions to tantalum could produce hard, high-melting alloys which might be ductile at room temperature. Such alloys offered excellent bases for complex alloy development, particularly with regard to the effect of rhenium on Group VI metals.8"10 In addition, there was the opportunity to examine flow and fracture modes in the vicinity of the DBT, with particular emphasis on the correlation between brittleness and fundamental deformation mechanisms. Myers11 has reported that recrystallized alloys with up to 10 pet W in tantalum are ductile at room temperature, but alloys with 20 pct W could not be swaged at temperatures as high as 500°C. The whole spectrum of Ta-W alloys has been surveyed by Braun, Sedlatschek, and Kiefferl2 using sintered powder compacts. In addition to some physical properties they reported a maximum hardness at about 50 at. pet W, dropping to much lower hardness levels for the pure components. They were able to cold work tantalum-base alloys with as much as 30 pet W and to warm work tungsten-base alloys with up to 20 pet Ta by procedures similar to those used for pure tungsten. EXPERIMENTAL In order to study deformation modes and to keep the impurity concentrations at a minimum, electron-beam zone melting was used to prepare single crystals of high purity. The electron-beam zone melting apparatus is similar to that described by Calverley, Davis, and ever" and incorporates a grid control rectifier to maintain control of emission current. Pure metals were refined by making three zone passes at 4 mm per min up the rod. Alloys were prepared by melting together wire of one constituent on a previously melted rod of the major constituent. Subsequently, two zone passes were made in opposite directions to level the composition after the manner suggested by pfann.14 Purification of the starting materials was accomplished by evaporation of the several impurities, and the degree to which this was accomplished is indicated in the chemical analyses of Table I. The uniformity of composition along a zone levelled rod was within the i 1 pet accuracy of the fluorescent X-ray technique used to determine composition. Crystallographic orientation of the

Jan 1, 1962

By D. A. Summers, C. J. Haas, G. B. Clark, J. W. Brown

While significant advances have been made in excavation of rock, largely in improvements in drilling, blasting, loading, and haulage, conventional operations have been improved until little feasible increase in efficiency or rate of advance appears possible. Tunnel-boring machines have been developed which will excavate at rapid rates in soft to medium- hard rock. Hypervelocity impact is being intensively investigated as a possible means of cutting and breaking rock, as well as lasers, electric current, explosive drilling, high frequency vibration, etc. The current development and use of high-velocity small-diameter water jets, metallic jets, and projectiles of various materials involve ultra-high-pressure phenomena of fundamental interest. Rock disintegration by water jets has been investigated in the USSR for over a decade. Large-diameter jets of low velocity are used to mine coal, and high-velocity capillary jets will cut and break rocks under laboratory conditions. Velocity ranges for breaking and cutting are dependent upon rock and jet properties, and pulsed jets break some rocks more easily than continuous jets. Spectacular laboratory results have been reported for breakage of unconfined blocks of some types of rocks. Compressors, pressure multipliers, gas explosion chambers, and water cannons have been used to generate jets. Jet properties, such as continuity, unit pressure, total pressure, and stability have been measured. Results agree with theory, although the latter has been established only for relatively low-velocity flow. Diameter, speed of traversing, and frequency of pulsed jets affect rock response. Investigations in Britain have only recently begun consideration of harder rocks and higher velocities, although water jet cores have been found to be more continuous at lower velocities than previously believed. Lower limits of jet velocity for rock cutting were established for the rocks investigated.

Jan 1, 1970

By E. C. van Reuth

FIFTY-three alloys have been examined in the Fe-W and Co-W alloy systems in an attempt to verify the finding of o phases in these systems as reported by Goldschmidt.' The alloys were examined metallographically and by X-ray diffraction. The 10-g specimens were made by powder metallurgy techniques. Very fine, high-purity powders were compressed in a double-acting die at 120,000 psi after hydrogen reduction. All compacts were then sintered for 200 hr at 950°C in a helium atmosphere. Metallographic investigation and X-ray diffraction proved this time to be sufficient to allow complete homogenization before the subsequent high-temperature anneal. Each specimen was then sealed into an evacuated silica capsule and annealed at 1400"or 1500 C (except two) for 25 hr. (The 60 pct Fe and 55 pct Co alloys taken to 1610"and 1680°C respectively were held at these temperatures for 1hr. However, since these structures were at equilibrium before the anneal, and in view of their resultant structures, it is assumed that they reached equilib-

Jan 1, 1960

By Thomas J. Pike, Keith G. Kirk, Mark F. Weider, Lawrence E. Welborn

As part of the mine permitting process as delegated by the Surface Mining Reclamation and Control Act of 1977 the regulatory authority must assess the probable hydrologic consequences and cumulative hydrologic impacts of surf ace mining. The U.S. Office of Surface Mining (OSM), in conjunction with Energy & Minerals Technology Assessment and ENCORE Systems Inc., has developed a user friendly groundwater model that is capable of predicting the effects of surface mining on groundwater quality and quantity. The model is a variation of the Prickett-Lonnquist model which has been modified to be specifically applicable to surface mine applications. This model is presently being used by OSM, the states, and industry to determine mining impacts on groundwater resources. The model is designed for use by the hydrologist with minimal computer training. The model accounts for multiple pumping wells, injection wells, multiple mine pits, and mine pit movement through time. This paper presents an example of how the model may be used in permit application review and how the model can be used by industry to simplify permit preparation.

Jan 1, 1983