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The following description is based on the film's narrative script: The film opens with a description of the terrain--tens of thousands of yearly snows compressed into glacial ice, stretching further than the eye can see. A single massive frozen cap--1 812 992 km2 (700 thou- sand sq miles) covering most of the land mass of the world's largest island, christened strangely enough--Greenland. Greenlanders comprise more than two-thirds of the 40 thousand Danish subjects who brave the elements in the Arctic Circle. Along the coastal fringe where the Gulf Stream sheds its last vestige of tropical warmth to temper Greenland summers, tiny villages survive In virtual isolation. Jagged fjords and creeping glaciers are barriers to conventional communication. There are no roads through the year-round ice. Yet, when there is wealth in the land, there are people to tame it, harnessing those unrelenting forces of nature if they can building and surviving in spite of them if they must. Near the tiny site of Marmorilik in west Greenland a gathering of men from places more benign came to challenge a sheer, frozen rock named Black Angel Mountain to tap a deposit of lead and zinc ore. As far back as the 19301s, surface investigation showed zinc and lead sulfides in the vicinity. In the mid-60's mountaineering geological examinations were made and deep-hole drilling, directed by Cominco Ltd., of Canada, confirmed the presence of an ore body, 600 m (2000 ft) above the fjord. These findings led to the formation In 1965 of Greenex A/S, a'Danish company with principal offices in Copenhagen. A utilization con- cession, with rigorous safety standards and environmental controls to

Jan 1, 1977

By Fuad S. Maayeh, Robert J. Evans, Paul M. Yavorsky

A description and capabilities of the Mine Roof Simulator at the Pittsburgh Mining Technology Center is illustrated for testing longwall roof support equipment. This unique Mine Roof Simulator has the capacity to exert 3 million lbs. of compressive force vertically and 1.6 million lbs. of force horizontally to simulate loads on hydraulic supports typically found in longwall mining. The supports that undergo testing are instrumented with strain gauges and photoelastic coatings such that critically strained areas become readily apparent. These critically strained areas are redesigned or retrofitted with appropriate reinforcement and retested. A data base will be accumulated from several support designs that will lead to an optimized design that will have the potential to reduce downtime by malfunctions of supports and thus increase productivity. A typical test procedure and analysis is given for a two leg 350 ton shield along with a description for placement of strain gauges, displacement gauges, and hydraulic pressure monitors for critical sites.

Jan 1, 1982

By M. L. Rudee, R. A. Huggins

Samples of iron containing nitrogen or carbon have been given treatments similar to those used in cold-work peak (CWP) measurements and examined by transmission electron microscopy. It was observed that the unusual and nonreproducible behavior of the carbon CWP can be explained by a strong tendency for carbon to form grain boundary precipitates at temperatures below those used for CWP measurements. These precipitates dissolved at the temperatures used in the CWP measurements. There was no evidence for nitrogen precipitation at grain boundaries. There was no indication of precipitation along dislocations in either carburized or nitrided samples given treatments similar to those of CWP measurements. Although it is possible that subelectron-microscopic clustering had occurred, this observation supports the theories of the CWP that are based on continuous atmospheres rather than on individual precipitates. In an earlier paper,' the present authors developed a new distribution function to predict the occupation of sites for interstitial impurity atoms around a dislocation. When this distribution was applied to the case of carbon and nitrogen in iron, it predicted that, if the temperature dependence of the concentration of solute atoms in the matrix was controlled by the presence of equilibrium carbide or nitride precipitates, the tendency for nitrogen to segregate to dislocations would be greater than that for carbon even though their binding energies to dislocations are identical. The cold-work internal-friction peak (CWP) is considered by most authors to be produced by the interaction of interstitial impurities with dislocations. Many investigators have studied the CWP in iron containing carbon and nitrogen and have observed a significant difference between its behavior in the two cases. In this paper a series of experiments will be reported that were initiated to determine whether the application of the new distribution function would explain the observed differences between the carbon and nitrogen CWP. Although it was found that the distribution function, pev se, did not explain the differences, the differences became clear, and some insight into the mechanism of the CWP was realized. Before reporting the present experiments, the literature pertaining to the differences between the carbon and nitrogen CWP in iron and the various mechanisms proposed for the CWP will be reviewed. LITERATURE REVIEW Snoek2 first observed the CWP in iron specimens containing nitrogen, but also reported a weak and unreliable peak in carburized samples. Later, Ke3 established that the CWP height was proportional to the degree of deformation. The presence of nitrogen alone would produce a peak of the same size as found in a sample containing both nitrogen and carbon, and KG concluded that the CWP was caused by nitrogen. In a discussion of G's paper it was reported that Dijkstra had investigated the CWP in samples that contained only carbon. He found it to be much smaller than the nitrogen peak and "unstable". KG et al.4 charged specimens of iron with both carbon and nitrogen. They observed that the carbon CWP was much smaller than that observed in nitrided samples, but that aging at 300°C caused the carbon peak to increase. A similar treatment produced no change in a nitrogen peak. Annealing at higher temperatures caused the height of the CWP in both the nitrogen and carbon samples to decrease. This behavior was also observed by Kamber et al. 5 who found that the activation energy for the annealing of the CWP was identical with the activation energy for the self-diffusion of iron. They concluded that the annihilation of dislocations by climb caused the reduction in the CWP height. Kamber et al. studied the "unstable" carbon peak in detail. They measured both the Snoek and CWP during various aging treatments. In carburized samples, aging at 100°C caused the Snoek peak to disappear, although the CWP peak remained small. However, a subsequent treatment for 5 hr at 240°C caused the CWP to reach a maximum. They proposed that an additional location for the carbon, other than whatever site produced the CWP, is present. In nitrided samples the CWP was completely developed as soon as a measurement was made; additional sites are not present. No explanation of either the additional site or the difference in the behavior of carbon and nitrogen was offered. petarra5 performed a systematic study of the effect of composition on the CWP. Using three kinds of "pure" iron, he showed that there was a residual CWP when the carbon and nitrogen concentrations had been reduced to less than that detectable by Snoek-peak measurements. He observed the same general annealing behavior and composition dependence as previous investigators, with the following exceptions. On first measuring the carbon CWP, it was found to be identical with the residual peak, and essentially independent of the carbon content. If the CWP was measured a second time in the same sample, it increased in size, but was still only about one-fourth the size of a CWP in a sample of the same iron nitrided to the same composition. On the other hand, a series of annealing experiments showed that the nitrogen CWP was not al-

Jan 1, 1967

By K. L. Sehgal

Minerals are the basis of modern civilization: their exploitation and effective utilization are a yard- stick for measuring the comparative prosperity of different nations. This is particularly true in India where industrialization is just beginning to pick up speed. Production targets for our Fourth Five Year Plan (1966-71) are far ahead of the figures for, say, 1950 (the year we won independence) and show the extent of the expansion. Many problems remain to be solved, not least of which is the shortage of raw materials. India is no novice at utilizing minerals. Archaeological ruins at Harappa and at other historical places in the country show evidence of the fact that the ancient Indians not only knew the art of winning minerals from the ground over 6000 years ago-they were also well acquainted with metallurgy. Some of the present sites of mineral exploitation are the same as those our ancestors worked for many centuries.

Jan 9, 1965

By W. M. Tuddenham, R. J. P. Lyon

In many areas surrounding the orebodies in mining districts rocks have been bleached and altered by the ore-forming solutions and have been oxidized during later weathering processes. A number of the rock-forming silicates have been broken down to clay, sericitic micas and chlorites have been developed, and pyrite may be found hundreds of feet outside the economic limits of the orebody. These halos of altered ground are prime targets used by geologists in many districts to delineate promising sites for drilling. Both in the field and in the laboratory it is often difficult to map these mineralogical changes in the halos in detail without numerous petrologic examinations. The secondary minerals are generally fine-grained, and since conversion of one mineral to another is often progressive, many alteration processes have not proceeded to completion (feldspars to clay to sericite mica). Qualitative detection of these minerals is difficult; quantitative determination is frequently impossible.

Jan 12, 1959

By W. M. Tuddenham, R. J. P. Lyon

In many areas surrounding the orebodies in mining districts rocks have been bleached and altered by the ore-forming solutions and have been oxidized during later weathering processes. A number of the rock-forming silic-ates have been broken down to clay, sericitic micas and chlorites have been developed, and pyrite may be found hundreds of feet outside the economic limits of the orebody. These halos of altered ground are prime targets used by geologists in many districts to delineate promising sites for drilling. Both in the field and in the laboratory it is often difficult to map these mineralogical changes in the halos in detail without numerous petrologic examinations. The secondary minerals are generally fine-grained, and since conversion of one mineral to another is often progressive, many alteration processes have not proceeded to completion (feldspars to clay to sericite mica). Qualitative detection of these minerals is difficult; quantitative determination is frequently impossible.

Jan 1, 1960

By M. T. Melvin, N. P. Kripakov

The practical application of a post-processing modeling procedure to simulate progressive rock failure around the periphery of coal mine entries is presented. This numerical scheme utilizes a simple rock model that incorporates easily obtainable input parameters consistent with basic rock mechanics principles. These parameters include the cohesion, angle of internal friction, modulus of elasticity, and Poisson's ratio of the bedded deposits that comprise the imediate roof, coal seam, and immediate floor. The geometry of the entry, along with the in situ stresses existing at a mine site prior to mining, are also considered in the analysis. The potential of this procedure as a predictive tool in determining the extent of pillar rib fracturing and yielding of the immediate roof and floor is evaluated assuming a Mohr- Coulomb failure criterion. The procedure is designed to be user oriented and is adaptable to any finite element code with linear elastic capability, making it particularly attractive to users with limited budgets and computer size.

Jan 1, 1983

By A. L. Baxley

An Untapped Energy Resource As much as 20 billion cubic feet of natural gas per day are flared from remote oil fields for lack of a commercially viable means of capturing, transporting, and marketing such gas. The magnitude of these gas flares can be put into perspective from an early satellite photograph (Fig. 1) which shows lights from the major cities of Russia and Eastern Europe dwarfed by the natural gas being flared in the Persian Gulf. Together, these wasted resources contain the energy equivalent of about one-half of the gasoline consumption in the United States today (Fig. 2). Additional trillions of cubic feet of natural gas are "shut-in" because of no economically viable means of commercial recovery. Methanol and liquified natural gas (LNG) are the only two practical fuel products which can be produced economically from these gas supplies. Many of these gas supplies are less than 500 million cubic feet of gas per day, making an LNG facility uneconomic. In contrast, barge-mounted methanol plants can economically convert billions of cubic feet of gas per day into safe, clean-burning methanol. The methanol approach offers the only economical route to transform vast, known reserves of natural gas into a highly versatile primary liquid fuel. Methanol Barges: An Innovative Solution The barges will be towed to suitable offshore and upriver locations such as Alaska, South America, Africa, Southeast Asia, Australia, New Zealand, and the South Pacific Islands, as well as fields in the Persian Gulf and Mediterranean Sea. At the offshore production site, a barge will be anchored by a single point mooring buoy that will also serve as an entry point for natural gas feedstock and an offloading point for methanol (Fig. 3). At some sites the barge would be beached. Each barge will produce methanol and store it in internal tanks with a capacity of 18 million gallons. The methanol will be offloaded into conventional tankers and safely transported directly to market. Unlike LNG, methanol requires neither specially built carriers nor specially built receiving terminals. Once a particular gas field has been exhausted, the barge will be towed to another location to continue production. Each barge will measure 320 by 500 ft, approximately the size of four football fields, and will have the capacity to produce 1 million gallons or 2800 metric tons of methanol per day, from approximately 100 million cubic feet of natural gas per day (Fig. 4). The barges will use the highly successful "low- pressure" design developed by the Lurgi Company of Germany, a process proven in land-based methanol plants throughout the world during the last ten years. The decision to use Lurgi technology for "sea-trans- portable" methanol plants was based on the higher efficiency and greater operability of the technology compared to other commercially proven processes. The conversion plant will be designed to accept a wide variety of feed gas compositions, and will produce chemical-grade methanol for the broadest market base (Fig. 5). To minimize costs and construction time, the barge-mounted plants will be built in the high technology environment of a domestic or foreign shipyard. Selection of the construction site for each barge will be dictated by the location of the production site and by the relative construction costs. A number of shipyards have the capacity to build several barges per year. The detailed marine engineering to integrate the design of the processing plant with the floating platform can be performed by numerous major engineering companies around the world. Production Economics The barge-mounted plant concept not only assures large volumes of methanol, but it also keeps the overall production cost low by minimizing construction cost and providing access to low cost natural gas feedstock with no alternative or a negative value. Together, these advantages make the barge-mounted methanol plants economical today. The cost structure of a new barge-mounted methanol plant differs from that of existing methanol producers around the world (Fig. 6). For example, if a U.S. Gulf Coast producer is paying $4.70/MMBtu in 1985 for natural gas, the barge plant could afford to pay about $1.6O/MMBtu for gas and be able to deliver methanol to the Gulf Coast at the same price. At some future date such as 1990, a gas cost of $6.70/MMBtu for a domestic producer would have cost parity with about $3.60/MMBtu gas cost for the barge plant. In many foreign markets, feedstocks other than natural gas are used for methanol production (Fig. 7). For example, most of Japan's capacity is based on LNG while Western Europe uses residual oil or naptha. Because these feedstocks are substantially more ex- pensive than natural gas used by U.S. producers, the barge plants will compete even more favorably in these foreign markets. As crude oil prices rise, the value of methanol in each of these markets will increase. However, the hierarchy of methanol values in these markets should remain unchanged. Furthermore, the cost advantage for using methanol in these markets will improve as world energy costs increase since the value of remote gas should not escalate significantly.

Jan 1, 1982

There's a right way and a wrong way to store diesel electric systems and similar equipment for generating on-site power, according to James Frankow, service manager for Allis-Chalmers Corp's Engine Division. In any event, the less storage the better. Many generating sets are stored before installation, especially when new construction is underway. Improper storage, or mothballing, can create initial reliability problems. Therefore; arrange for inside storage with no drastic extremes in temperature or humidity. If engines and alternators are stored in areas other than inside a dirt-free and temperature-controlled building, the unit or engine should be completely covered and protected against the environment. Before covering it with a canvas or with plastic, the unit should first be sealed at the following critical engine openings:

Jan 3, 1978

By James F. McConnell, Charles W. Statler

Pennsylvania's existing large coal-fired units are limited to 2.0, 1.8, or 0.6 lb of sulfur per million Btu fired, depending on site location. Multi-stream coal preparation can be employed on system basis to extract the highest quality fraction of coal for use in units requiring the lowest sulfur. The middling fraction can be directed to units permitted higher sulfur. General Public Utilities Corp. has concluded that it is feasible to advance the state-of-the-art of heavy media coal preparation to produce an intensively cleaned primary product of 1.3 sp gr of less than 0.6 lb of sulfur per million Btu for the new unit and a middling product of 2.0 lb of sulfur per million Btu for existing units.

Jan 1, 1977

By P. E. Phillips

INTRODUCTION Rocky Mountain Energy is the mining subsidiary of the Union Pacific Corporation, and has been active m uranium exploration since 1966. Since 1970, RME's uranium activities have been funded 50% by Mono Power, the fuels supply division of Southern California Edision. RME and Mono recognized the need for development of new methods for recovering low grade uranium deposits, and contacted Halliburton Services in regard to in situ leaching, because of Halliburton oil industry experience. As a result, a joint venture between the three parties was formed in 1974. BEAR CREEK The first ISL test was at the Bear Creek deposit in the Powder River Basin of Wyoming, about 60 miles north of Douglas. The mineralized sand is the tertiary Wasatch formation, which is an arkosic sandstone. The sand typically contains about 10% clay. The predominant clay being montmorillonite with some kaolin and illite. The roll front type trends occur along the flanks of old stream channels. This deposit was being considered for exploitation as an open pit mine. Routine amenability testing indicated it was quite amenable to a conventional acid leach, consuming about 50 lbs. of sulfuric acid per ton of ore in an agitation leach, while recovering more than 95% of the uranium. Hydrology testing indicated a permeability of about 1 darcy. The groundwater has a pH of about 8. 0 and TDS of about 1200. Test Facility The Bear Creek test was a summer-only operation, with no effort towards weather-proofing. Uranium was removed from the recovered leach solution by fixed bed ion-exchange columns. Loaded resin was eluted with strong sulfuric acid. The recovery plant was designed for simplicity of operation, with little concern for the grade or form of the yellowcake product. The plant was constructed of PVC piping and valves, fiberglass reinforced tanks, and stainless steel pumps. All waste streams were directed toward a lined evaporation pond. Wellfield The test pattern was a 30 foot radius 5 spot, with wells fully penetrating the 30 foot ore sand to a total depth of about 165 feet. The injection wells were three-inch PVC with slotted casing, while the producer was eight-inch I. D. , with a stainless steel screen. The eight-inch well was necessary in order to accommodate a six-inch stainless steel pump. Wells were cemented using cement baskets, at the top of the sand, to contain a latex acid resistant cement. Leach Conditions The lixiviant generally contained from five to seven gpl sulfuric acid, and about 0. 5 gpl hydrogen peroxide. The pH was generally 1.4 and EMF was usually -550 millivolts. Injection rates were rather variable from well to well, with a total injection rate between 12 and 25 GPM. Production rate was set at 25 GPM, since the production pump could not be throttled more than that. Approximately two pore volumes of solution were injected during the three-month test. Leach Results Injectivity was quite variable, but was generally rather poor, because of poor completion techniques. The problem stemmed from injecting before the injection wells had been completely cleaned of drilling mud. Pregnant solutions averaged about 50 ppm U308, with groundwater dilution varying from 10 to 50%, depending on the injection rate. Injectivity did decline with time, probably as a result of contamination of the well faces. A total of 1000 lbs U308 had been recovered when the test was shut down. This probably represented about 10% of the mineral under leach.

Jan 1, 1979

By Jay A. Carpenter

IN six years the construction of Hoover Dam and the power plants probably will have reached the operating stage and this vast new source of power will then be continuously available for industry. The height of the darn will be 580 ft. and the average annual flow of the Colorado River is calculated at approximately 24,000 cu.ft. per sec. If this full head and average flow can be maintained the year round, about one million horsepower will be generated. The U. S. Reclamation engineers, taking into consideration the probable range in flow and head, have set the figure for power contracts at 660,000 firm horsepower, which can be assured at all times of the year. During the months of heavy run-off of water from the Colorado River Basin the power plants should be able to generate the full 1,000,000 hp. capacity of the power plants, so there will be 340,000 excess or secondary horsepower. The cost of firm power at the switchboard will be close to 2.15 mills per kw.-hr., equal to $14.05 per hp.-yr., and the cost of the secondary or off-peak power will be close to 0.8 mills per kw.-hr., or $5.22 per hp.-yr. In no place in the country can such cheap power be obtained today. The electrochemical industry is in a state of flux because the power costs from its old sources have increased so much (to $30 per hp.-yr. at Niagara) that the industries have had to seek new sources, so they have gone to Canada and Norway and built new plants.

Jan 1, 1932

By Mark David Rankin

This paper represents a general assessment of the primary factors driving the market for mobile offshore drilling rigs and the utility of those factors as choice variables for the offshore drilling program planner.

Jan 1, 1982

By John J. Dran

The elaborate analytical techniques for risk analysis used by the large mining companies in conjunction with the valuation of mineral reserve sites are totally inappropriate for the small miner. The small miner does not possess the financial and technical resources which are available to the large companies for such risk analysis. Even if these resources were available to him, the relatively small size of his investment would not justify a huge expenditure for risk analysis. What is required by the small miner is an improvement over the single point estimates provided by the valuation techniques that he currently uses. Such improvement should provide an indication of the extent to which the true value (known only after the fact) might differ from his estimated value of the mineral reserve site. In addition, a rough indication of the chance of occurrence of various differences between the true and estimated values would be helpful to him. These improvements must be obtained at low cost to be useful to the small miner. Such improvements would have to be based on a simple system requiring very few additional estimates by the miner. The small miner is not accustomed to dealing with sophisticated risk analysis techniques. Hence, any complex, time-consuming approach would be doomed to disuse or possible misuse. A simple, uncomplicated approach requiring a minimum of additional estimates by the miner can be based on a system devised by Frederick S. Hillier Although Hillier's method can be applied to various mineral reserve valuation methods used by the small miner, this note is specifically oriented to the discounted cash flow model. The basic discounted cash flow (DCF) approach provides a single point estimate of value and introduces the concept of risk (i.e. the possibility that the annual cash flows may differ from their estimated values and thus lead to an incorrect investment value) through the use of a risk-adjusted discount rate. This approach simply lowers the present value estimate with increases in the discount rate (i.e. increases in the risk assessment). The single point estimate still remains. Although the lower value estimate makes it less likely that the risky investment will be deemed profitable and undertaken, it provides no indication of risk that is suitable for examination and analysis. In addition to the "best guess" estimate of annual net cash flows required in the DCF model, application of the Hillier risk analysis model requires that the miner

Jan 1, 1976

By David R. Maneval, Sylvester Lemezis

All acid mine drain waters, regardless of source, share certain characteristics; but they do differ in exact chemical composition, degree of acidity, and total solids content. Any serious program to treat such waters must recognize these differences and apply to each specific case the technique which offers the best promise of each specific case the technique which offers the best promise of technical and economic success. The Pennsylvania Dept. of Mines and Mineral Industries has originated and funded studies of many different treatment means. Neutralization with lime is now being used on 200 different polluted streams in Pennsylvania, and multistage flash evaporation has been selected for a particularly large and troublesome outfall near Wilkes-Barre, Pa. A 5 x 106 gpd plant for this latter site is now being designed by Westinghouse Electric Corp. which developed a concentration process based on multistage flash evaporation as part of the State's research program.

Jan 1, 1973

These springs arc situated on the south bank of the river about four miles below the City of Great Falls. In addition to the spring on the bank there are several in the bed of the river. Estimates on the flow of all these vary from 350 to 600 cubic feet per second, and as the temperature is practically constant at 53° F. throughout the year, the effect on the river water is to prevent the formation of anchor ice at the Rainbow Fails power development below, trouble of this source being in evidence every winter at the Black Eagle Falls above. Geologists claim that the water of the Giant Springs is derived from seepage through an old pre-glacial channel of the Missouri River now occupied by Sand Coulee, five miles up-stream from Great Falls. The water in this buried channel seeps through the flat-lying sandstone of the region and again unites with the present stream at the site of the springs.

Jan 1, 1913

By S. A. TAYLOR

THERE is probably no other mineral industry of which the public has as much information and misinformation as it has of the coal industry. Unfortunately, however, the general public's knowledge of the coal industry, outside of the particular kind of coal it is accustomed to, by reason of use, is largely made up of information received from newspaper and popular magazine articles, in which the mine workers are depicted as overworked and mistreated men, and the coal operators as "coal barons." Those who have any specific knowledge of exact conditions in the coal industry know how unjust and un- fair such an opinion of the coal industry is, not only to the miner but to the operator as well. Many reporters and writers of magazine articles are misled by statements regarding the condition of the miners that are exaggerated and not founded on facts and, if an investigation of the conditions of the miner's work, his habitation and surroundings were fairly made, it would at least compel more truthful statements by those who write for public reading. That such an investigation would not reveal anything that was wrong, or anything to be censured or cured, no one, I think, would maintain, but I do think that any fair investigation of the facts would show that conditions in and around the newer and later-developed coal mines and communities would compare favorably with those of manufacturing districts, and that where the mines and com- munities are old and not very attractive places to work, or live in, they carry with them other considerations, compensating for these conditions, and cannot be remedied by reason of a lack of sufficient coal to warrant economically any costly changes.

Jan 1, 1926

By James Aston

A PROPER consideration of this subject is not confined to the technical channels of production and metallurgy. It concerns an industry, and should cover economic aspects which are of material importance in any program of development. The discussion may logically be treated under three subdivisions, as follows: (1) manufacture, (2) characteristics related to quality of material; (3) adaptability and exploitation of product. MANUFACTURE OF WROUGHT IRON The manufacture of wrought iron is the most ancient art of the ferrous metal industry. The eighty years or less of existence of processes identi-fied with our modern "Age of Steel" is a relatively brief interval com-pared with the several thousand years associated with the production of wrought iron by man. From the primitive early methods of production, manufacture for many centuries followed the line of direct reduction. There were developments as experience was gained through the years; but man's needs for a strong, ductile, forgeable product were met by reducing the ore to metallic iron in a single-stage operation. Following the development several centuries ago of what has become our modern blast-furnace operation, manufacture of wrought iron was gradually transformed into a two-stage method of first producing cast iron and then refining this to the desired degree of forgeability; the fore-runner in principle of today's scheme of manufacture of steel. The product retained the essential characteristics of highly refined base metal with iron-silicate slag incorporation, which were associated with the material resulting from direct reduction methods. Cort's invention of the puddling process in 1784 is a landmark in wrought-iron manufacture. It consisted essentially in adapting a coal-fired reverberatory furnace to the refining operation; thus lifting the industry out of the slough of

Jan 1, 1935

By R. E. Ogilvie, H. C. Gatos, R. E. Hanneman

The ejj-ect of high pressures on chemical inter-diffusion in the Fe-V system was determined by analyses of concentration vs distance profiles of atmospheric and high-pressure diffusion couples. Diffusion data were obtained as a function of tern -perature and composition. Activation energies, activation volumes, and frequency factors were determined at 1 atm, 20 kbars, and 40 kbars as a function concentration in the a and y phases. The A great deal of research has been carried out in the measurement and understanding of binary chemical inter diffusion in solids. Studies of the effects of high pressure on interdiffusion in binary systems, however, have been virtually nonexistent until the present work. This paper gives a detailed account of the effect of high pressure on interdiffusion and the Kirkendall effect in the Fe-V system. The present data are compared to existing theo- Kirkendall effects were measured at 1 atm and 40 kbars. At 1 atm Dy > DFe at the marker concentration; however, Dv approaches DFe under pressure, and at 40 kbars the values are approximately equal. The high-pressure and atmospheric diffusion data are evaluated on the basis of theoretical models. Chemical analyses of the diffusion -couple profiles were made using an electron microbeam probe. retical treatments of pressure dependence of diffusion which are based upon self-diffusion studies. THEORY The rates of atomic migration in metals and alloys are regulated by the repulsive forces exerted on an atom during its motion from one equilibrium lattice site to another and by the availability of a jump site. Application of high pressure is expected to decrease diffusion rates because it decreases interatomic distances as well as defect concentrations. A number of theoretical treatments have been focused on the problem of calculating self-diffusion coefficients in solids under atmospheric pressure. In general, the vacancy mechanism of diffusion appears to be dominant at high temperatures in most metallic systems. The migration of an atom by this

Jan 1, 1965

By Günter Petzow, Siegfried Steeb

DURING an investigation of the U-Co-A1, U-Ir-A1, and U-Ni-A1 ternary systems, three previously unknown phases have been identified which correspond to the phases UCoA1, UIrA1, and UNiA1, and which be- long to the C22 (Fe2P) type (P 6 2m). In the following the structure determination of the new ternary phases is reported. The alloys have been prepared in an arc furnace under purified argon from 99.97 wt pct U, 99.83 wt pct Co, 99.99 wt pct Al, 99.95 wt pct Ni, and 99.97 wt pct Ir. The pellets obtained were bright and brittle; chemical analyses agreed with the nominal compositions. To obtain equilibrium, the samples were annealed in evacuated quartz capsules at 950°C for 30 hr and then quenched in water. Guinier photographs were processed and evaluated according to a method already described previously.1,2 The hkl's, measured and calculated sin2 6 values, and in the case of UCoAl only calculated and estimated intensities, are given in Tables I to 111. Lattice parameters refined according to the least-squares method and the respective mean-square variations are presented in Table IV. Lattice parameters, especially the c/a ratio, lead to the assumption that the three phases are crystallizing in the C22-type structure. For the calculation of the intensities given in Table I, the atomic positions recently reported by wyckoff3 have been accepted for the C22 (Fe2P) type. The uranium atoms were assumed to be in phosphorus sites; furthermore the scattering amplitudes of the boron atoms have been averaged in the stoichiometric formula UB2 according to atomic percentages; i.e., for these atoms a statistical distribution on the iron sites was assumed. The two smallest distances between a uranium and

Jan 1, 1967