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By J. Th. Erb

Oil is found in commercial quantities in the islands of Sumatra, Java, Borneo, Tarakan and Ceram. The oil deposits of the Dutch East Indies and Sarawak are with one exception of Tertiary origin and as a rule are bound to anticlinal structures. The number of layers varies in most fields and in some of them asmuch as 14 oil-producing levels have been established. The crude oil varies rather much in composition. Some of it, particularly from North and South Sumatra, has a gasoline content up to 50 Per cent. Borneo produces mainly wax oil, while the Tarakan oil can be used directly as liquid fuel. In Java both wax and wax-free oil are produced. ' In all important fields installations have been erected to treat the wet gas. The lean gas is used for gas-lift purposes, Marietta process, and as fuel for boilers and motors, either in the fields or in the refineries. Formerly only percussion systems (Canadian, Californian and a drilling system devised especially for the purposes of the Royal Dutch Petroleum Concern) were applied in the Dutch East Indies, but in recent years the rotary system has been predominant and good results have been obtained with it. The deepest producer has recently been struck in South Sumatra at a depth of 1624 m. (5328 ft.), with a daily production of about 350 cu. m. crude oil. The crude is brought by an extensive system of trunk lines to the refineries, of which one is in North Sumatra (Pangkalan Brandan), two arc in South Sumatra near the town of Palembang, two in East ,Java (Tjepoe and Wonokromo), one in East Borneo (Balik Papan) and one in Sarawak (Miri). Production The principal producing concerns in the 'East Indies are: De Bataafsche Petroleum Maatschappij, the producing subsidiary of the Royal Dutch Petroleum Concern; Sarawak Oilfields Ltd., one of the

Jan 1, 1929

By F. Keeler, C. M. Craighead

Aluminum alloys containing magnesium and silicon are susceptible to strengthening and hardening by suitable heat-treatments, and they constitute a class of alloys of considerable commercial importance. Generally, they contain these two elements in the proportions required for the formation of the intermetallic compound Mg2Si, or an excess of silicon; no commercial wrought alloys are made with an appreciable excess of magnesium. The reason for not having excess magnesium is obvious from the results given in this paper, since it is shown that excess magnesium results in a proportional decrease in the solubility of Mg2Si. This is the eighteenthl of a series of papers from the Aluminum Research Laboratories dealing with the equilibrium relations in aluminum-alloy systems; most of the previous publications concerned binary aluminum-alloy systems; this is the fourth of a group pertaining to ternary aluminum-alloy systems. The work on this system was completed in 1930, but the results were not published because of the pressure of other work. Hanson and Gaylor2, in 1921, presented the results of an extensive investigation of the aluminum-magnesium-silicon system. Their results indicated that an excess of magnesium over the amount required to form the compound MgzSi caused a noticeable decrease in the solid solubility of MgzSi in aluminum. A more recent investigation3 in these laboratories showed that the solid solubility of MgzSi in aluminum was 1.85 per cent at 595' C. and decreased to 0.30 per cent at 300' C. The results of the latter investigation were used as the basis for the present work. The Present Investigation In the present investigation, a study was made of the effect of various amounts of excess magnesium upon the solid solubility of MgzSi in

Jan 1, 1936

By AIME AIME

M R. WEIGEL'S present position as Chairman of the Institute's nonmetallics group arises from twenty years of experience in that field, from 1921 to 1926 as mineral technologist for the Bureau of Mines, in Washington, and since then for the Missouri Pacific R.R. Co., with headquarters in St. Louis. This rail- road serves an extensive region in and about the southern central states, from Omaha to the extreme southern tip of Texas, and from southern Illinois to Pueblo, Colorado, and it is Mr. Weigel's job to get as much freight for the road as possible from the mineral industry in this area. Much of the present and potential mineral production is in the non- metallic group.

Jan 1, 1940

By L. M. Howe, J. Gordon Parr, E. Saarema

THE decreasing solid solubility limit at the titanium-rich end of the Ti-Cu constitutional diagram,' Fig. 1, suggests the possibility that titanium-rich alloys may be age-hardenable. However, results obtained by Holden et al. reproduced in Fig. 2 show that after quenching from 790°C the age-hardening of an alloy containing 1.7 pet Cu is very slight, while a 0.8 pet alloy decreases in hardness, during heat treatment at 400°C. It was believed possible that powder samples of alloys might show different results from the lump samples used by Holden et al., since small particles are often more sensitive to diffusion processes than larger samples. Consequently, a 1.9 pet (by weight) Cu alloy was made by the technique of levitation melting," checked for homogeneity, and filings of 48-65 Tyler screen size were cut from it for aging experiments. The filings were helium-quenched (by a technique described previously)' from 790°C, sealed in vacuo in silica tubes and aged at temperatures of 400°, 450°, and 500°C. Microscopic and X-ray examinations failed to reveal any structural changes during the aging process. This is not too surprising since early stages of precipitation do not usually manifest themselves in ways that are readily detectable by metallographic methods, and the extent of precipitation on overaging a 1.9 pet alloy is very small. However, hardness readings (taken on a Bergs-man micro hardness tester, using a 25 g load applied to a diamond indenter) do show a hardness peak at each aging temperature, Fig. 3. About a dozen readings were taken on each heat treated sample; the highest reading and the lowest reading were ignored and an average taken of the remaining values. In

Jan 1, 1957

By Charles S. Robinson

Abstract-The Henderson ore body is east of the Continental Divide in the Front Range of the Colorado Rocky Mountains, about 80 km (50 miles) west of Denver. The ore body is being developed for mining by workings that extend more than 1100 m (3500 ft) below the topographic surface. During construction of the mine workings, ground water in fractures in crystalline rocks has been encountered. From 1969 to 1973, Charles S. Robinson B Associates Inc., in cooperation with the engineering and geologic staffs of the Climax Molybdenum Company, a division of Amax Inc., studied the ground water geology of the Henderson mine development area. Detailed geologic records of the Henderson mine were available as a result of the exploration, evaluation and development of the mine. Records of the flow, chemical composition and temperature of the ground water at and near the surface, from the entire mine, from portions of the mine, and from exploration holes drilled in the mine, were kept as the mine was developed. Where possible, ground water pressures in drill holes and changes in pressure with time, were recorded. The geologic, hydrologic and chemical data were correlated. The following conclusions were drawn from the correlations: The ground water in the Henderson mine occurs in fractures in Precambrian igneous and metasedimentay rocks and in a series of Tertiary intrusive rocks. Two zones of ground water were recognized; an active zone, in which the fracture systems are recharged and discharged annually into the surface water system, and a passive zone, in which the fractures were filled with water in the geologic past Discharge from the passive zone is through mine workings that intersect the fracture systems. Discharge from a fracture or fracture system is initially high but decreases with time. The rate of decrease inflow (or pressure) is exponential. By measuring the change inflow with time, it is possible to calculate the amount of flow at some given period of time in the future. Based on changes in rate of flow and pressure, and the geology, and assuming rates of mining of the ore, it will be possible to predict the volumes of water that will have to be handled during the life of the mine and the area around the mine that will be drained by the mining operation.

Jan 8, 1978

By J. Mizrahi, A. Brillantshtein, A. Mitzmager, O. Schächter

The separation of synthetic mixtures of heavy minerals by hindered settling classification and jigging was comparatively tested in water and five organic heavy liquids, of various specific gravities and viscosities. It was found that in the hindered settling classification process the separation efficiency was directly proportional to the concentration criterion, the liquid viscosity being a minor factor. There is therefore a decisive advantage in using heavy liquids as classification medium. In the jigging process the advantage of using a heavy liquid is masked by the detrimental effect of a higher liquid viscosity, which, in this case constitutes an important factor. Considerable interest has been aroused lately by the development of mineral beneficiation techniques 1,2 using TBE (tetrabromoethane), a heavy liquid of specific gravity of 2.96, which has been made available for industrial use by a new process3 producing TBE directly from the Dead Sea brines at a reasonable price. Most of the applications investigated until now were based on the sink-float separation of minerals in a heavy liquid of intermediate specific gravity. The TBE can be conveniently diluted with many organic solvents, and thus sharp separations are possible in a wide range of specific gravities up to 2.96. Although this maximum specific gravity is sufficient on most cases for the elimination of the bulk of the barren gangue and the production of marketable concentrates, some practical problems came up for investigation in which the separation of two (or more) minerals, heavier than TBE, was required.* *Among the cases studied in the IMI Laboratorles which fall into this category we can mention: alluvial deposits, such as heavy minerals in sea sand, tin deposits, or ground coarse-grained rocks, such as pegmatites. In such cases where, due to the petrographic structure, further fine grinding is required in order to achieve the liberation of the heavy components, the

Jan 1, 1964

By K. F. G. Hosking

I read Professor Gaudin's paper with great interest and pleasure because for some time I have held that the chemical aspect of comminution is a subject of considerable importance to the mineral dresser and deserves to be thoroughly investigated. It does seem appropriate, however, to emphasize the fact that "fresh" edges and corners produced by the grinding of solids display enhanced reactivity has been recognized and utilized in the development of certain mineral identification techniques. Some of these techniques are worth noting, not only because they might facilitate research in the aspect of mineral dressing under discussion, but also because they emphasize the fact that many mineral species commonly regarded as being very inert can display a surprising reactivity when in the freshly ground state. In 1951 Isakov published a number of tests for the components of certain mineral species which depend essentially on grinding in a mortar a mixture of the material under investigation with a solid reagent. Thus when stibnite, 4(Sb2S,), is ground with sodium or potassium hydroxide, the antimony is revealed by a momentary development of a yellow color which changes in air to orange-red. Other antimony minerals need a preliminary treatment before the test can be carried out. This consists of grinding with aluminium sulfate, ferric sulfate or potassium bisulfate, and breathing upon the resultant mixture.

Aug 1, 1956

By William P. Blake

The salt-beds at Salton, on the line of the Southern Pacific railway, in San Diego county, California, have been successfully worked for many years by the corporation known as the East Liverpool Salt Co., and the salt has been largely used upon the Pacific coast generally and in the interior. But the industry has lately been destroyed by the overflow from the Colorado river. The salt is dissolved, and the waves of the Salton sea now roll 50 ft. above the site of this once thriving and growing business. The salt-bed was evidently the residual accumulation from the waters of an ancient lake, which I have named Cahuilla, from the name by which a large part of the valley—the home of the Cahuilla tribe of Indians—is known. The deposit covered a comparatively small area in the lowest part of the valley, 280 R. or more below the sea-level. This depressed area is now generally known as the Colorado desert, but has a soil of wonderful fertility wherever water can be had on its surface. The deserted beaches, and the water-lines, only a few feet above tide-level, upon the rocks of the bordering mountains, as well as a great abundance of shells in the soil, all bear decisive testimony to the former occupation of the valley by water. The depression is topographically the northern end of the Gulf of California, from which it is now separated by the delta of the Colorado river, extending practically from the mouth of the Gila river across the valley to the coast mountains on the

Jan 1, 1908

By Henry Rogatz

Oil.—During the year 1938, there were 434 oil wells drilled in the Texas Panhandle, increasing the daily initial production by 192,706 bbl. —that is, 229 fewer oil wells drilled than in the previous year, with a decrease in total daily initial production of 129,626 bbl. The total daily potential of the field on Dec. 1, 1938, as determined by the Texas Railroad Commission, was 1,250,645 bbl., an increase of 210,663 bbl. over the previous year. On Dec. 1, 1938, the daily allowable of 82,466 bbl. was assigned to the field to be produced from 3931 wells. The total amount of oil produced for the year was 23,227,170 bbl. The total proven productive area includes 148,298 acres. This is 30,248 acres more than for last year, and represents a more accurate calculation of the areas and not new discoveries. Gas.—There were 103 gas wells drilled during 1938, having a combined open flow of 3,166,300,000 cu. ft.; that is, 65 less than the number of wells drilled in 1937, with a decrease in the open flow of 3,144,488 cu. ft. per day. Pipe-line Gas.—The pipe-line companies withdrew 230,307,854,000 cu. ft. of gas (a daily average of 630,980,000 cu. ft.). The total withdrawals by pipe line decreased 5,624,481,000 ft. from that of 1937. Natural Gaso1ine.—Throughout the greater part of the year, 46 gasoline-extraction plants processed 1,376,186,000 cu. ft. per day, a total of 502,308,010,000 cu. ft. for the year. This gas yielded about 275,875,000 gal. of natural gasoline. The total daily capacity of all the plants is 2,519,500,000 cu. ft. During the latter part of 1938, one of these plants was shut down, leaving 45 plants operating at the close of the year. Carbon Black.—Thirty carbon-black plants operated during 1938, burning 266,881,000,000 cu. ft., or a daily amount of 731,180,000 cu. ft. This produced approximately 400,000,000 lb. of carbon black. During the year one plant was dismantled and two plants were shut down.

Jan 1, 1939

By Henry Rogatz

Oil.—During the year 1938, there were 434 oil wells drilled in the Texas Panhandle, increasing the daily initial production by 192,706 bbl. —that is, 229 fewer oil wells drilled than in the previous year, with a decrease in total daily initial production of 129,626 bbl. The total daily potential of the field on Dec. 1, 1938, as determined by the Texas Railroad Commission, was 1,250,645 bbl., an increase of 210,663 bbl. over the previous year. On Dec. 1, 1938, the daily allowable of 82,466 bbl. was assigned to the field to be produced from 3931 wells. The total amount of oil produced for the year was 23,227,170 bbl. The total proven productive area includes 148,298 acres. This is 30,248 acres more than for last year, and represents a more accurate calculation of the areas and not new discoveries. Gas.—There were 103 gas wells drilled during 1938, having a combined open flow of 3,166,300,000 cu. ft.; that is, 65 less than the number of wells drilled in 1937, with a decrease in the open flow of 3,144,488 cu. ft. per day. Pipe-line Gas.—The pipe-line companies withdrew 230,307,854,000 cu. ft. of gas (a daily average of 630,980,000 cu. ft.). The total withdrawals by pipe line decreased 5,624,481,000 ft. from that of 1937. Natural Gaso1ine.—Throughout the greater part of the year, 46 gasoline-extraction plants processed 1,376,186,000 cu. ft. per day, a total of 502,308,010,000 cu. ft. for the year. This gas yielded about 275,875,000 gal. of natural gasoline. The total daily capacity of all the plants is 2,519,500,000 cu. ft. During the latter part of 1938, one of these plants was shut down, leaving 45 plants operating at the close of the year. Carbon Black.—Thirty carbon-black plants operated during 1938, burning 266,881,000,000 cu. ft., or a daily amount of 731,180,000 cu. ft. This produced approximately 400,000,000 lb. of carbon black. During the year one plant was dismantled and two plants were shut down.

Jan 1, 1939

By Donald McLaughlin

INCREASING variety of interests among mining geologists is becoming more and more marked, as the frontier of their science and of its applications continues to expand. Each of the traditional lines of inquiry provides its crop of new and better defined problems, and answers to them are being found in far more precise terms than in the past as older uncertainties .are swept away with the sharper techniques and the even sharper ideas of modern geology. A glance over the assemblage of projects and publications in 1939 reveals conspicuous activity in many different parts of the front, such as the attack on the controversial question of the acid or alkaline character of ore-forming solutions, the place of mineral districts in the larger structural framework of continents, and the place of ore shoots in the local patterns of districts. Instructive comparisons are being made which cut across lines of older correlations or which reinforce them by pointing out heretofore ne-

Jan 1, 1940

Striving to do a better job of ad- ministering the letter and spirit of the Federal Coal Mine Health and Safety Act of 1969, the Interior Department recently invited criticism-and got it. The criticisms were voiced on July 1 and 2 at the first of a series of public meetings being held by the Office of Hearings and Appeals at the Department's behest. Later meetings, at which all interested parties are invited to comment, are to be announced in the press and the Federal Register. Persons wishing to participate in the meetings should contact the Director, Office of Hearings and Appeals, 1015 Wilson Blvd., Arlington, Va. 22203. At the first Hearing, USBM Director Elburt F. Osborn outlined the progress his agency has made to date in implementing the law on three fronts: enforcement, education and research. Since the Health and Safety Act became law on December 30. 1969, he said, the Bureau's force of inspectors has grown from a mere 300 to almost 1100, while mine inspections have increased from 10,265 in 1970 to 11,021 for the first six months of 1971. On the educational front. Osborn said, the Bureau now has some 60 instructors who have trained about 50,000 miners in safety procedures since March 30. 1971. Classes at the new Federal Mine Safety Academy for both government and industry personnel begin on September 1, 1971. he added. Health and safety re- search, meanwhile, has been allot- ted $20.1 million for the 1971 Fiscal Year. Of this, $8.1 million is assigned to the Bureau and $12.3 million to contracts with universities and private companies. Admittedly, Osborn said, the mine fatality rate is still unacceptable, hut it was lower in the first half of 1971 than ever before---0.73 per million man hours and 0.31 per million tons of coal.

Jan 1, 1971

By J. J. Gilman

Examination showed that characteristic cleavage step patterns are observed on the cleavage surfaces of undeformed, slipped, bent, twinned, compressed, and indented zinc crystals; and the effect of temperature is discussed. Dimples were seen to produce cleavage steps in a treelike pattern in otherwise undeformed crystals. The steps seem to originate when cracks intersect screw dislocations. IT has been known for a long time that the path of fracture in polycrystals may be discontinuous (see Jaffe, Reed, and Mannl for review). Recently, Kies, Sullivan, and Irwin2 have proposed, and given evidence, that crack propagation is discontinuous within individual crystals as well. Other evidence has been given by Low.' When discontinuous cracks within a crystal join together to make a macrocrack, the lamellae between each set of two cracks are torn somewhere, forming small cliffs. These cliffs appear as lines when the cleavage surface is observed microscopically.4,5 The lines have been called vein, tree, and riverlike markings by various authors, and they have sometimes been mistaken for fissures. The descriptive term cleavage steps is used in this paper. Cleavage steps vary in height over a wide range of values, from molecular dimensionsG to lor. and larger. Kies, Sullivan, and Irwin,2 as well as George,' have shown that the gross cleavage step patterns for plastics, polycrystalline metals, and for mono-crystals are sometimes similar. Thus, they depend mostly on the mechanical variables that prevail during cleavage and are relatively insensitive to the structure of the material. For example, parabolic markings2,7,8 sometimes result when cracks open up ahead of, and not coplanar with, the main crack front. If the advance crack has the same velocity as the main crack, their intersection line is a parabola, otherwise it is a hyperbola or an ellipse. The patterns are strongly affected by differences in crack velocities. This results in chevron patterns which point to the place of origin of the main crack. It is the purpose of this paper to demonstrate the existence of a mechanism of cleavage step formation which is a continuous rather than a discontinuous process. Also, certain characteristic step patterns are described, and the strong effect of temperature is shown. The specimens were zinc monocrystals (grown from 99.999+ pct pure metal). These were cleaved at room temperature and at — 196°C. Results and Discussion Cleavage step patterns are highly variable from point to point on a given specimen, as well as from one specimen to another. Although the patterns shown in the photographs are typical, they have been selected for graphic illustration. Figs. la and lb compare undeformed crystals that were cleaved at —196 °C and room temperature, respectively. Cleavage at room temperature (Fig. lb) resulted in a higher density of high steps (dark black lines) and enhanced the visibility of the fine background markings. Deformation by simple slip caused no marked change in the step patterns until the glide strain reached about 1.0. But, as Fig. lc shows, the density of high cleavage steps was greatly increased by large glide strains. Corrugations lying perpendicular to the slip direction may also be seen in Fig. lc. These are caused by deformation bands. The cleavage resistance of the crystal of Fig. lc was very high compared to undeformed crystals (estimated by the force on a needle required for cleavage). Striking and varied cleavage step patterns were observed on bent crystals. Two characteristic patterns that were observed on crystals bent at 25°C, and cleaved by reverse bending at —196°C, are shown in Figs. 2a and 2b. The first, Fig. 2a, consists of V-shaped lines similar to the parabolas of other materials2,7 Fig. 2b shows a pattern that is the equivalent of Fig. la, consisting of faint background lines with a few higher step markings. Cleavage of bent crystals at room temperature resulted in Figs. 2c and 2d. Now, the cleavage step lines show a strong tendency to follow one of two perpendicular paths. In Fig. 2c (bent once), many of the cleavage step components that lie parallel to the bend axis are assembled into irregular lines. In Fig. 2d (bent twice), the cleavage steps again tend to consist of two perpendicular components, but neither of the components is assembled into lines. Also, the step density is higher.

Jan 1, 1956

By E. A. von Hahn, T. R. lngraham

Cementation rates ulere studied by rotating an elec-tropolished or etched copper strip in aqueous solutions, of either perchloric acid or alkaline cyanide, containing silver ions. The rates of cementation were more rapid in acidic media than in cyanide media. In both, the rates varied with the rate of rotation of the copper strip. The deposits formed in the acidic solutions were finely divided, loosely adhering powders. Those formed in the cyanide solutions were dense and adherent. The presence of the deposits influenced the cementation rates. In the acidic solutions the rate was enhanced, possibly because of the increased cathodic area. In the alkaline solutions the rates were decreased in the presence of the deposits. This has been attributed to restricting the diffusion of the copper ion from the rnetal outward into the bulk of the solution. In an earlier paper1 the authors described a kinetic study of the cementation of palladium on copper in perchloric acid solutions. That work indicated that there were two stages in the palladium cementation process. The first, more rapid stage was consistent with rate control by the diffusion of Pd11 ions to the copper surface and/or by chemical reaction at the surface. The second stage was consistent with rate control by the diffusion of copper ions from the copper surface, through the deposit, out into the main body of solution. The effect of the type of deposit on the rate of cementation is of particular interest because it may be one of the primary features involved when large quantities of metal are to be cemented from solution. No substantial investigations of the effect seem to have been made. Accordingly, an extension of the previous work was arranged to study the cementation of silver on copper. This system was selected because of the convenience of the analytical methods, the previously established technology with copper, and the fact that the system could be studied in both acidic and alkaline media. By selecting perchloric acid and alkaline cyanide solutions as the media, it was hoped that some assessment might be made of the effects, on cementation, of having the silver ion present in a virtually uncomplexed state and in a highly complexed state. EXPERIMENTAL The cementation rates were studied, as previously described,' by rotating a copper strip (1.0 by 23.2 cm) clamped to the peripheral surface of a lucite cylinder. The solutions were kept at constant temperatures (±0.05°C) under an atmosphere of purified nitrogen, and samples were taken periodically for analysis. The initial solution volume was 1000 ml and the sample volume 5 ml. The initial silver(1) ion concentrations were made low (0.5 to 1.0 x 10-4 moles per liter) to minimize the influence of the cemented deposit on rates. The solutions were prepared by dilution of suitable aliquots of silver perchlorate and silver cyanide stock solutions. Both stock solutions were prepared from purified silver powder (Johnson, Matthey, and Mallory Ltd.) with redistilled deoxygenated water, and they were kept under an atmosphere of purified nitrogen. To prepare the stock solutions, weighed amounts of silver powder were dissolved with nitric acid. For the AgC104 stock solution the silver nitrate solution was evaporated twice to near dryness with perchloric acid and then made up to volume: For the NaAg(cN)2 stock solution, the silver ions were precipitated with sodium hydroxide solution. The precipitate was filtered, washed thoroughly with redistilled water, dissolved with 1.1 times the required stoichiometric amount of sodium cyanide solution, and made up to volume. The small amounts of free perchloric acid and sodium cyanide present in the stock solutions were disregarded in the preparation of the solutions. The copper strips were cut accurately from 0.025-in. sheet (American Metal Climax OFHC brand) and annealed for 1.5 hr at 470°C in a stream of nitrogen. Analyses of the solution samples for silver and copper were done with a Techtron Model AA-3 atomic absorption spectrophotometer. Calibration standards of the same composition as the experimental solutions were prepared and analyzed simultaneously with the samples. No difficulty was experienced in the analyses, and the reproducibility was within 1 to 2 pct in both alkaline cyanide and perchloric acid solutions.

Jan 1, 1968

By K. R. Carson, J. Weertman

An attempt is made to ascertain the mechanism of tangle and cell formation and its dependence upon dislocation-interstitial carbon interactions. The strain-hardening behavior of single crystals of 3.25 pct Si-Fe was determined at 300° and 425°K and under conditions of both continuous and interrupted tensile strain. Significantly enhanced hardening was observed in crystals deformed at the elevated temperature, and it was further accentuated by interrupted straining. Transmission electron microscopy was used to study the resultant dislocation structures. Strain aging was found to aid tangle and cell formation at 425°K, but at both temperatures embryo tangles formed solely from primary glide dislocations, presumably by a process involving cross slip and "mushrooming". IN the course of plastic deformation all bcc metals and alloys develop a dislocation structure characterized by loose-knit groups of tangled dislocations. With increasing strain the tangles become more tightly knit and grow larger; finally a three-dimensional cellular substructure is formed:1 This process has been observed with the transmission electron microscope.'-l7 However, most investigations were confined to the study of nearly pure polycrystalline metals at relatively low temperatures. At intermediate temperatures, 0.17 to 0.14 Tm where T, is the melting temperature in degrees absolute, the mobility of interstitial impurities such as carbon is high enough to permit migration to nearby glide dislocations but is still low enough so that a significant drag force is exerted.18,19 it is also in this temperature range that a hump occurs in the curve of work-hardening rate vs temperature for iron. Analogous plots for tantalum" and columbiumzo show a definite upward trend in the work-hardening rate. Keh and Weissman1 have pointed out that this behavior may be explained solely on the basis of changes in the dislocation configuration: at low temperatures the dislocations tend to be relatively straight and uniformly distributed, but at intermediate temperatures tightly knit tangles and cellular substructure appear. The interference of these tangles with glide dislocations causes the observed increase in the work-hardening rate. This explanation appears reasonable, yet one might ask what factors cause tangle formation to be so favorable at intermediate temperatures. It seens likely that the strong dislocation-interstitial interactions which are known to occur in this temperature range are at least partly responsible," with the magnitude of the effect being proportional to the interstitial concentration. The purpose of the present work is to study the relationship between tangle formation and strain hardening in a bcc metal in the temperature range 0.17 to 0.4 Tm. Particular emphasis was placed upon a study of the effects of interstitial-dislocation interactions. Single crystals of 3.25 pct Si-Fe containing about 200 ppm of C in solid solution were used in the investigation for the following reasons: 1) The mobility of interstitial carbon in 3.25 pct Si-Fe is negligible at 300°K but increases rapidly at slightly elevated temperature22. Hence, differences between the flow curves and dislocation structures of crystals deformed at 300°K, 0.17 T,, and crystals deformed, say, at 425°K, 0.24 Tm, should be appreciable because of the enhanced dislocation-carbon interactions at the elevated temperature. This effect was accentuated in some samples by interrupted straining, thereby introducing a certain amount of aging. 2) Near room temperature, slip in suitably oriented 3.25 pct Si-Fe single crystals is largely confined to the (110) planes.23'24 Dislocation structures formed under conditions of single glide are the least complicated and their method of formation is the most easily discernable. 3) Dislocations in Si-Fe can be tightly locked with carbon atmospheres by a low-temperature aging treatment. The subsequent thinning of samples to foil thicbess causes little or no rearrangement in the dislocation structure.25 EXPERIMENTAL PROCEDURE Large single-crystal sheets of 3.25 pct Si-Fe were donated by Dr. C. G. Dunn of the General Electric Research Laboratory, Schenectady, N. Y. The orientations of the sheets were determined and slabs 1.0 by 0.25 by 0.05 in. were cut such that the desired tensile axis corresponded to the long dimension. The slabs were mechanically polished and subsequently decar-burized by heating at 1000°C for 3 days in a flowing wet-hydrogen atmosphere. A carbon content of about 200 ppm was introduced by heating at 805°C for 25 min in a flowing atmosphere of dry hydrogen containing heptane vapor. Shaped copper tools were then used to spark-machine at 0.125 by 0.50 in. gage length onto each slab. Vacuum annealing at 1225°C for 2 days followed by a quench into the cold end of the furnace to retain carbon in solid solution concluded the soecimen preparation. Continuous tensile flow curves for crystals of severa1 orientations Were obtained both at 300' and 425°K. A strain rate of 6.67 x 10-4 Per set was used in these and all other tests. Crystals oriented for single glide, B and D in Fig. 1, were subjected to a 3.5 pct plastic elongation to insure uniform slip along the gage length; they were then immediately subjected to interrupted strain cycling as indicated in Fig. 2(a). Each cycle consisted of unloading to 1.5 kg per sq mm, holding

Jan 1, 1969

By F. W. Luerssen, J. F. Elliott

F LUSHING the early slag from a stationary open Fhearth having a high percentage of hot metal in its charge is necessary in order to remove silica from the system. The flush slag is strongly oxidizing and is somewhat acidic. It has, however, considerable capacity to extract phosphorus from the bath and it also removes considerable manganese. It seems probable that factors which control the distribution of phosphorus and manganese between slag and metal in the refining period also should be dominant in the flush and postflush periods. Several studies, as summarized elsewhere,1,2 support the viewpoint that conditions closely approaching equilibrium for these elements are rather readily established during the refining period. Over the years these studies have repeatedly demonstrated that 1—high slag v01ume, 2—low bath and slag temperature, 3—basic slag, and 4—strongly oxidizing slag favor rapid elimination of phosphorus from the bath to the slag. They also show that the following conditions favor retention of manganese in the bath: 1—low slag volume, 2—high bath and slag temperature, 3— basic slag, and 4—minimum oxidizing power of slag. When it is considered that the flush slag often carries as high as 75 pct of the manganese charged and only 25 to 60 pct of the phosphorus charged, it is evident that in removing silica much manganese is sacrificed but phosphorus removal is far from conplete. Because of overriding circumstances, this is accepted in most operations and actually it is considered to be inevitable. This may account for the fact that little attention has been paid to conditions affecting the elimination of phosphorus and manganese in the flush slag. A recent study of the behavior of various charge oxides has developed considerable information on the flush and postflush periods. Because the data are felt to be of general interest, they have been brought together and Presented in this paper. The object is to show the various factors in the flush and postflush periods which influence elimination of phosphorus and manganese. Physical Conditions During and After Flushing Physical conditions existing during the flush vary from plant to plant, from shop to shop, from furnace to furnace, and even from heat to heat. They are strongly influenced by the physical and chemical character of the charge oxide which is ordinarily necessary to provide sufficient oxidizing power early in the heat. Invariably the period is characterized by a vigorous reaction between the principal re-actants: the hot metal being added and the charge oxide. During the flush, it is probable that the slag acts to some extent as an oxidizer; but, because of the critical influence of the behavior of the charge oxid'e on flushing action, it seems apparent that the oxide itself is the dominant oxidizer. Fig. 1 shows the course of two heats which were selected as being typical of the group studied. Heat A was charged with 55 pet hot metal, based on the total metallics charged, and heat B had 57 pct hot metal. As indicated in Table I and Fig. 1, the melt-down slag, which is not usually voluminous and which is principally FeO, expands greatly in volume and will show rather high levels of SiO2, MnO, and P2O5 very soon after the beginning of the hot metal addition. Simultaneously, large volumes of CO are liberated which cause violent mixing of slag and metal. It is of interest to note that the time required to bring carbon down to a low level is very much longer than that required for the removal of silicon, manganese, or phosphorus. At the end of flush, carbon in the bath is still approximately 2 pct. When strongly reducing hot metal is brought into contact with strongly oxidizing conditions within the furnace! it is probable that the rate of mass transfer to the slag (and atmosphere) of silicon, manganese, phosphorus, and carbon initially depends principally on the rates at which the two participating phases are brought into contact That is, it depends on the nature of the various reactions. Later in the flush period, when the scrap is virtually all dissolved and the action of the bath has settled down to a steady and somewhat gentle boil, it is likely that other factors, such as the transfer of oxygen across the slag-metal interface, become dominant. The temperature of the slag-metal system is far from uniform. Heat is being driven by the flame down through the slag. Bubbling and surging of the metal also frequently brings portions of the bath in contact with the flame. At areas of contact between the ore and liquid metal, or slag and liquid metal, the oxidizing reactions generate much heat. On the other hand, scrap is being melted which tends to absorb large quantities of heat. Because the liquid bath is high in carbon, the steel scrap is brought into solution rapidly. This can proceed at a rather low temperature; and until much of the scrap has been taken into solution, the bath temperature would not be expected to increase appreciably. Consideration of these factors leads to the conclusion that during the flush period the slag should be rather hot and the bath relatively cold. Both observation and temperature measurements bear this out. Experimental Data The extended program of charge oxide evaluation permitted study of the widely varying conditions existing during the flushing period. Slag and metal analyses and bath temperatures reported herein (Tables I and 11) were obtained toward the latter portion of the work. Four different types of charge oxide, sinter, two types of hydraulic cement-bonded soft ores, and a pyrobonded agglomerate were used in the study. Although the heats reported were from only one 205 ton furnace, they show variations in flush slag analyses all the way from 25 pct FeO, which is typical with the use of a hard natural charge ore, to 45 pct FeO which resulted when a very poorly agglomerated fine ore was used. The physical behavior of the flushes showed a correspondingly wide variation from well controlled reactions to violent surges following periods of inac-

Jan 1, 1956

By F. M., Waring

F. M. WARING,* Altoona, Pa.-The necessity for conserving tin has recently been very forcibly brought to the attention of all consumers, and efforts are now being made to reduce the tin content in certain alloys or to substitute other alloys not containing tin. The approximate composition of the non-ferrous alloys in general use on the Pennsylvania Railroad are given in the accompanying table. Phosphor bronze is used principally for rod bushings, main-rod brasses, and crosshead shoes. Ex. B bronze is used to a small extent for backs of car and coach bearings, but the majority of these are now made of the car-journal bronze, which contains, on the average, about 5 per cent. tin.

Jan 12, 1918

By E. P. JENNINQS

(Cleveland meeting, October, 1912.) LARGE deposits of titaniferous iron-ore occur at Caribou, an old silver-mining camp in Boulder county, Colo., 17 miles west by south of Boulder, and a few miles northwest of the tungsten-mines. Professor Regis Chauvenet 1 published a part analysis of the ore many years ago, but gave no description of the wall-rock. Caribou hill, which contains both the silver-bearing veins and the iron-ore deposits, is a low dome of gabbro surrounded by the Archaean schists and gneisses of the Front range of the Rocky mountains, the peaks of which, a few miles west of Caribou, attain an elevation exceeding 12,000 ft. The gabbro stock is roughly elliptical in outline, with approximate diameters of 1 and 3 miles. The crest of the dome is 10,500 ft. above sea-level, and the town and ore-deposits are 500 ft. lower. Outcrops of the iron-ore occur in the town and extend NW. for 2,000 ft., where they disappear under the swampy meadows of Caribou park. Portions of the deposit are covered by drift, but one continuous outcrop is 900 ft. long and from 200 to 250 ft. wide. A second deposit is 0.25 mile south of the town along the eastern slope of the hill. It is not as well defined as the north bed, but is approximately 1,000 ft. long and from 100 to 200 ft. wide. The easily disintegrated ore does not form prominent outcrops, but the outlines of the deposits are readily traced by the large amount of ore fragments that cover the ground. Trenches and pits sunk on the outcrop expose a roughly banded magnetic iron-ore, with pyroxene as the principal gangue-mineral. The Gabbro. This rock was classified in the field as a gabbro from the presence of pyroxene and striated feldspars, and for convenience the field-name will be retained. 1 Chauvenet, Regis, Biennial Report of State School of Mines, Golden, Colo., p. 16 (1886).

Oct 1, 1912

By H. W. Schreiber, G. R. Castle

INTRODUCTION The small mining company faces the dilemma of how to finance the development of its properties. Many of these small companies don't have the financial resources to pay for development costs from their own funds and frequently they do not even have the financial strength to permit them to borrow the money needed for development. A project financing can sometimes be arranged in such a way as to solve this dilemma. A typical project financing will not provide the answer to the "little guy's" problem because most project financings require that the sponsors of the project provide completion undertakings and sometimes other undertakings. These undertakings are often a prerequisite to obtaining financing, and if the sponsor is not financially strong enough to provide the comfort that the lenders require, then the sponsor will have difficulty obtaining financing no matter what undertakings are offered. However, with a little imagination and the right set of circumstances, a project financing can sometimes provide the solution to the small mining company's problem. The Strathcona Sound Project is unusually suited as a case study because the sponsor, Mineral Resources International Limited,(MRI) was able to arrange a project financing for the development of the project even though the lenders probably would not have been willing to loan a similar amount of money direct to MRI based on the full faith and credit of MRI's balance sheet. The way that MRI was able to arrange this financing makes for an interesting story. THE CASE In early 1974, MRI owned 100% of a small to medium sized zinc - lead - silver massive sulfide deposit (Property) located 475 miles north of the Arctic Circle less than two miles from deep water on Strathcona Sound which is a shipping zone in the Canadian Arctic. The Property was situated at a desolate location except for an Eskimo settlement (Arctic Bay) which was about 20 miles west of the Property. In other words, the project required that complete infrastructure would need to be installed in this far northern location. Independent reserve and feasibility studies (Study) had been completed on the Property which confirmed a total of 6,825,000 tons of reserves classified and summarized as shown below on Table I: [ ] These reserves were based on 229 diamond drill holes totalling 58,909 feet and were established on a cut-off grade of 7% zinc and a minimum mining height of seven feet. The overall mining recovery rate was estimated at not less than 85% and not more than 90%. The feasibility study indicated that it would cost an estimated $45,044,000 to develop an underground mine, a concentrator, a town-site, a power plant, storage facility, loading dock, a tailings disposal area and an airstrip on the Property with an annual capacity of 525,000 tons of ore per year. The construction period was expected to take two years and projected capital costs were broken down as set forth below on Table II:

Jan 1, 1985

By J. Cervik, P. C. Thakur, S. D. Lauer

Methane drainage by cross-measure boreholes on retreat longwall faces can be a viable alternative to the vertical gob degas boreholes under favorable circumstances. The research was done in a mine working Pittsburgh coal seam in northern West Virginia under USBM Cooperative Agreement No. 14-09-0050-3252. The study was the first application of this technique to Pittsburgh coal seam. A total of 14 small diameter, inclined boreholes were drilled over a retreat longwall panel from gate roads, to intersect the overlying coal seams. All boreholes were manifolded to a pipeline and the gob gas was extracted by a surface exhaust fan. The methane capture ratio was poor at 7% to 18% at various stages of the longwall panel. A vertical gob degas borehole captured an additional 20% gas. Poor results were due to premature failures of the cross-measure boreholes leading to air leakage. For better performance, the boreholes should be drilled from a point 30 to 45 m (98 to 148 ft) from longwall pillar over the largest chain pillar. The standpipe should be grouted for at least 6 m (20 ft), and the entry containing boreholes and the pipeline must be supported to ensure access for maintenance and optimization of methane capture. Coursing the ventilation air around longwall such that it forces methane migration toward cross-measure boreholes can further improve methane capture. The optimum vertical inclination is 45º ± 10º.

Jan 1, 1986