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By O. N. Carlson, K. E. Solie

The brittle-ductile transition temperatures of single and poly crystalline chromium metal were studied as a function of nitrogen concentration and chromium nitride distribution. It was observed that In recent years there has been an increasing interest in chromium-base alloys for high-temperature applications. The principal disadvantages, however, have been the difficulties of fabrication and the design problems associated with a material of such limited ductility. Various studies have been the effects noted in the poly crystalline material are essentially reversed in the single crystals. These observations are discussed in terms of existing theories for the brittleness of chromium. conducted recently directed toward a determination of the cause of this brittleness and to find ways for minimizing its effects. Allen et al.,' Wain Abrahamson and rant,' and weaver4 have carried out studies on the effects of interstitial impurities on the brittle-ductile transition of chromium metal of various degrees of purity. These investigations have shown that oxygen has little or no effect on the transition temperature of chromium in all conditions studied but that carbon increases the transition temperature under all conditions tested. Nitrogen was found to increase the transition temperature in the wrought condition and in the quenched or cast conditionS but reportedly has no effect in the furnace-cooled condition.

Jan 1, 1964

By L. L. Newman

As soon as the Congress recognized the alarming rate at which our domestic oil resources were being depleted during the war, it took action to step up the rate of research and development which the Bureau of Mines had been conducting for several years on the production of synthetic liquid fuels from coals. Under Public Law 290, approved April 5, 1944, funds were authorized for the Bureau to proceed with research, development, design and construction of demonstration plants for the hydrogenation of coal, the synthesis of oil from carbon monoxide and hydrogen, and the distillation of oil from shale. During the latter part of 1944, when it became evident that the collapse of Germany was near, a Technical Oil Mission was organized to study the Ger- man techniques of synthetic oil production. Since the cost of hydrogen or synthesis gas is one of the major factors of expense in the operation of hydrogenation or synthesis gas processes, the Bureau of Mines considered it of prime importance to include on the mission gas engineers whose instructions were to examine closely the methods employed by the Germans in solving the problem of providing low- cost hydrogen or synthesis gas for their very extensive operations on synthetic liquid fuels. The Solid Fuels Mission and the Utilities Mission, as well as the Army and Navy Missions, also included teams for the study of German gas production. Although their objectives naturally differed from those of the Technical Oil Mission and from each other, it was recognized that there was considerable overlapping of their fields of investigation. Duplication of effort, however, was largely avoided through the close cooperation between the group leaders of these missions. For example, although I went to Europe as a member of the Technical Oil Mission, my first German assignment was actually made by Dr. Harry F. Yancey, leader of the Solid Fuels Mission- to investigate the brown-coal gasification methods in central Germany. The art of gasification in the United States and England, and to a large extent in the proximity of the coking-coal regions of Germany and the rest of continental Europe, depends essentially on two stages of operation; namely, carbonization and intermittent water-gas generation. As far as the United States is concerned, complete gasification in a single stage of operation is rarely practiced, except in gas-producer operations where the product is a relatively lean gas consumed close to the point of manufacture, and for water-gas production with anthracite as a generator fuel. Complete gasification of bituminous coal has been the subject of numerous investigations. Many relatively simple modifications of the water-gas generator have been tried to permit the direct gasification of low-cost bituminous coal instead of high- cost coke and anthracite for the production of water gas. Although varying degrees of success have been achieved and the water gas produced generally has been higher in calorific value, in only a few isolated in- stances has there been any sustained use of bituminous coal for water-gas production for public utility uses after the shortages of anthracite and coke have been lessened.

Jan 1, 1946

By B. H. Dunshee

THIS paper is not intended to be a technical discussion of square-set framing as used in mines, but merely a short description of the different kinds of framing that have been used in the Butte mines, and what has been decided upon, after years of practical experience, as being the best, taking into consideration the physical condition of the veins and country rock, and. also the supply of timber available for mining purposes. Butte is, essentially, a square-set district. Virginia City, Nev., was the first mining camp to use this method of timbering, and to Philip Deidesheimer, who went to the Ophir mine in 1860, is given the credit of solving the problem of square-set framing, where large bodies of ore were stoped and the timbers were supposed to hold the ground from caving without any filling. That he did his work well is shown by the fact that the main features of his framing are in use to-day. In the Butte mines the conditions are such that this method of timbering is generally used. We do not, of course, depend upon the timbers any more than is necessary. The worked-out stopes are filled with waste rock as close behind the miners as possible and not interfere with mining operations. The waste rock is obtained from development work on the different levels or from the surface. In the earlier days of mining in Butte there were numerous independent companies and naturally there were different ideas as to the best way to frame the square sets, although the general features were the same.

Jan 8, 1913

By Robert Anderson

ROUGHLY, a crack in a casting may be considered, for the moment, to be due to fracture of the alloy resulting from the stress set up by the contraction in volume on passing from the liquid to the solid state. Cracks may be external or surface, internal or deep-seated, or incipient or so-called strain cracks. Draws may appear as depressions, unevenness, and "pinching in" of the surface of a casting. Roughly, draws are due to contraction in volume and are governed largely by the same factors as cracks. A casting may be cracked, however, without being drawn. Shrinkage is a foundry term; it connotes the contraction in volume of a metal or alloy on passing from the liquid to the solid state. Pattern-makers' shrinkage is the total contraction in volume (including liquid, solidification, and solid shrinkage) that occurs when an alloy is poured into a mold. The contraction in volume of aluminum is one of the principal factors affecting the occurrence of cracks, as will be shown later, and the question of shrinkage and its control requires careful study in any treatment of cracking in castings. In the case of, sand and die castings, cracks have been attributed to a number of causes, but in the case of most light aluminum alloys, they are due to the large contraction in volume on freezing and the lack of its regulation or control. The most important factors are: (1) Contraction in volume; (2) composition of alloy; (3) quality of melting charge; (4) design of casting; (5) method of molding; (6) hardness of ramming; (7) method of gating; (8) hardness and characteristics of cores; (9) chills; (10) risers; (11) melting temperatures; (12) furnace used for melting; (13) pouring tempera-tures; (14) inclusions in alloys; (15) hot shortness of alloys; and (16) physical properties of alloys at high temperatures. Of these, the first, second, third, and eleventh to sixteenth involve ascertainable metallurgical facts; the remainder are largely matters of opinion, judgment and technical knowledge of men experienced in the production of castings.

Jan 10, 1921

By M. C. Leverett

KNOWLEDGE of the theory underlying the behavior of mixtures of fluids in reservoir rocks is essential to the proper solution of certain types of problems in petroleum pro-duction, but is as yet incompletely devel-oped. The object of this paper is to show the application of well established thermody-namic and physical principles to these prob-lems, and thus to assist in the development of the basic theory. For convenience the problems to be considered here may be divided into two groups: I. Static problems, involving only the static balance between capillary forces and those due to the difference in densities of the fluids; i.e., gravitational forces. 2. Dynamic problems, involving analysis of the motion of mixtures of immiscible fluids in porous media under the influence of forces due to gravity, capillarity, and an impressed external pressure differential. CAPILLARY EQUILIBRIUM IN SANDS Under this heading the static type of problem will be discussed and the results of experimental investigations on the capillary properties of unconsolidated sands will be presented. Although the discussion of this section is, in a sense, prefatory to the treat-ment of problems of mixture flow, the con-cepts developed here have considerable intrinsic importance apart from their ap-plication to flow problems. For, it is reason-able to postulate that the reservoir fluids are, owing to their long existence in undis-turbed mutual contact prior to exploitation, in substantial equilibrium. It follows that their distribution in the reservoir at the time of tapping should be entirely predict-able from the theory of capillary equi-librium, provided certain experimentally measurable properties of the reservoir rock are known. Knowledge of the distribution of the several fluids in the reservoir is, of course, helpful in the estimation of reserves and in other problems. It is to be emphasized that throughout the discussion of capillary statics it is as-sumed that the fluids are in equilibrium from the capillary standpoint. Thus, water, where it is referred to as being in a reser-voir, will be understood to be interstitial water, present at the time of drilling the reservoir, commonly termed "connate" water. The theory developed here is perfectly general for any porous solid, whether a carefully prepared unconsolidated sand or a natural sandstone from an oil reservoir. At present, however, only problems in-volving clean, unconsolidated sands can be made to yield numerical solutions, since only such sands have been adequately in-vestigated experimentally. Experimental evaluation of the pertinent properties of natural reservoir rocks will permit the ex-tension of the numerical treatment to prob-lems involving these materials. We shall now consider in some detail the static equilibrium of fluid mixtures in porous solids; that is, the manner in which the reservoir fluids are distributed vertically when the forces due to capillarity are just balanced by those due to gravitation.

Jan 1, 1940

By Ernest Burchard

A RECONNAISSANCE Of the manganese-and chrome-ore deposits of Cuba was made by the writer, as a representative of the U. S. Geological Survey, in company with Mr. Albert Burch of the Bureau of Mines under instructions of the Secretary of the. Interior, in the Spring of 1918. The object of the study was to obtain authentic information for the use of the United States Government as to the location, character, quantity, and availability of the manganese and chrome-ore deposits in Cuba. Accordingly, the work comprised the examination of such deposits as seemed to be of promise, without regard to stage of development, with a view to determination of the quantity and quality of ore likely to become available for shipment during 1918 and 1919, and of the tonnage of ore in reserve. While it was possible to visit most of the deposits that seemed to be of promise, there was not sufficient time to visit all that were brought to our attention, some of which may have merit. Manganese ore is found in Cuba in Oriente, Santa Clara, and Pinar del Rio Provinces, but in Oriente Province only does it occur in large commercial quantities. There, the deposits are in three areas: one north of Santiago de Cuba, one south of Bayamo and Baire, and one on the Caribbean coast between Torquino Peak and Portillo. In Santa Clara Province, a little ore has been found near the Caribbean coast west of Trinidad; and in Pinar del Rio Province, manganiferous material occurs north of the city of Pinar del Rio and farther west near Mendoza. The manganese ores of Cuba occur, principally, in sedimentary rocks, such as limestone, sandstone, and shale, that are in places metamorphosed, and. in beds that originally may have been water-laid tuff

Jan 3, 1919

By C. W. Washburne

THE waters of many oil fields have been regarded as buried sea water which has been retained in the sediments since the time of their deposition. The preservation of connate water through geological time has seemed improbable to only a few geologists, but there is room for doubt that buried sea water could remain in the strata during their periods of deformation and during the many subsequent epochs of. the circulation of meteoric ground-water. Some have even suggested that the calcium chloride water in the deep mines of the Lake Superior region is ancient sea water buried in the Algonkian lavas, but it is hard to understand how such water could be derived from the highly sodic and sulphatic water of the sea. It would seem more plausible to connect the calcium chloride with the highly calcic magmas of the greenstones in which it is found. Chemical analyses of waters associated with oil differ widely from the composition of sea water, requiring extensive alteration of the latter, if the former is truly its derivative. The first notable difference is the general absence of sulphates from oil-field waters, but this has been explained satisfactorily through reduction by hydrocarbons and organic matter. Oil reduces sulphates with the production of hydrogen sulphide (or sulphur), water, and carbonates (or carbon dioxide). The second striking difference is in the high ratio of chlorine to sodium. An examination of the analyses of chloride waters from oil fields shows that they contain a large relative excess of chlorine over that in sea water. Moreover, there is difficulty in finding chemical reactions that are probable in nature, by which sea water could be converted into anything like the chloride waters of oil fields. In the latter a large part of the chlorine occurs as calcium acid magnesium chloride. This condition might be produced by the removal of sodium carbonate, which; however, cannot be precipitated in the presence of much calcium or, magnesium.

Jan 3, 1914

By W. R. Ingalls

SOME months ago, I had occasion to make an investigation that introduced the subject of blue powder that is produced as a byproduct in zinc dis-tillation. Although every zinc smelter is aware that more or less blue powder production is inevitable and there is a common practice as regards the treatment of it, the specific and quantitative data respecting the subject were more imperfect than would have been expected. I had reports from eight important works. Some of the data were especially determined for my investigation. Speaking generally, there is a good deal of uniformity in the figures, all of which show that the blue powder product, bears a large proportion to the ore originally charged into the retorts; that a large proportion of the retort capacity is devoted to the redistillation of blue powder; and that of the spelter product of a furnace about 30 per cent. is derived from blue powder, i.e., it is zinc that has been distilled twice. The figures from the works are given in the following table:

Jan 4, 1922

By Hallan Marsh

THE subject of this paper is apt to bring to mind wells ranging from 6000 to over 8000 ft. in depth. However, it is uncommon to pump wells at depths greater than about 5000 ft. Fig. 1 shows the number of wells being pumped at various depths by one company in Southern California. FIG. 1.-NUMBER OF WELLS BEING PUMPED BY ONE COMPANY FROM VARIOUS DEPTHS IN SOUTHERN CALIFORNIA. A few companies have a very few wells pumping at depths greater than this. This paper will deal with wells between 3000 and 5500 ft. in depth. Most California oils at these depths are between 25° and 35 gravity. The subject is so broad that it will be necessary to omit many interesting phases, and to treat others very briefly. Power, power transmission equipment, power efficiency, counterbalancing, sucker rods, pumps and volumetric efficiency will be discussed.

Jan 1, 1928

By E. I. Salkovitz, F. W. von Batchelder

AS Slawson1 and others have already shown, from a geometrical view twinning in the diamond structure may be considered as a reflection across a (111) plane or as a reflection across a (112) plane. An analysis by Ellis and Treuting2 showed that the twinning plane must be the (111) plane, but that a twin might have lateral boundaries along (112) planes. Earlier Slawson1 and Ellis3 had shown that only (111) twinning was present in diamond and germanium respectively. Since an ingot of silicon, 1 in. in diam and 1 1/2 in. long, prepared from Dupont silicon to which 0.2 pct Be had been added was available, it was examined for twinning. The ingot had been cooled slowly from the bottom. A section 1/16 in. thick was ground off from the bottom and then the ingot was sliced vertically through the center. Spectrographic analysis indicated only faint traces of iron and silver, in addition to the beryllium. The sample was first etched with a hot solution of 10 pct NaOH in water.and photographed. Back-reflection Laue patterns were made of the vertical and horizontal sections in the regions designated in Fig. 1. Orientations were obtained for each twin using the Greninger technique. Several regions of the same orientation were found; thus regions A and K were identical, similarly N and P, and C, G, J, and L. Knowing the angles between the traces of the twinning plane on the surface and the specimen axis, the indices of the twinning plane were deduced. In all cases the twinning plane was found to be (111); lateral boundaries, however, were found which were (112) such as the one indicated in Fig. 1. Therefore, as in the case of diamond1 and germanium' only (111) twinning occurs in silicon. We wish to thank Mr. Hino for the use of the ingot as well as for its metallographic preparation. References 1C. B. Slawson: American Mineralogist (1950) 35, p. 193. 2 W. C. Ellis and R. C. Treuting: Trans. AIME (1951) 191, p. 53; Journal of Metals (January 1951). 3W. C. Ellis: Trans. AIME (1950) 188, p. 886; Journal of Metals (June 1950).

Jan 1, 1953

By Mehl, Robert F.

IT has been shown by numerous studies that the orientations of new metal crystals are determined by the orientations of the crystals in the original matrix, whether these new crystals are formed by recrystalliza-tion, by precipitation from solid solutions, or by transitions in the solid state. The orientations of crystals formed by recrystallization of cold-worked worked metals that bear preferred orientations are occasionally simply related to the initial preferred orientation; often, however, the relation-ship is not simple, but complicated and obscure in origin.1 The orientations of crystals formed by precipitation from solid solu-tions have been shown by many studies in this and other countries to be determined by the orientation of the crystals of the solid solution stable at the higher temperatures, though here again complicated cases have been found and no general theory is available .2 Related to this latter class

Jan 1, 1934

By Ezequiel Ordoñez

THE great activity with which the oil resources of the northern Cantons of the State of Veracruz have been developed has largely resulted from the great success obtained by the important explorations carried out since 1902 in the Ebano district in the North, and several years later near Tuxpam, in the South. It must not be thought that these successes were quickly obtained, since the preliminary studies by good experts, the acquisition of what were thought to be the most promising coast lands, the extensive clearing thereof, and finally the number of unsuccessful drillings at great depth, signified an original outlay of some ten's of millions of dollars before finding commercial oil. The discovery of oil in industrial quantities at Cerro de la Pez, Ebano district, and the famous Dos Bocas gusher some years later, which was burned, once and for all made famous the Veracruz coast, where today is concentrated the Mexican output of mineral oil. In .1917, this production was nearly 50,000,000 bbl. It is well known that this output represents only a fraction of what the wells in actual production can furnish, because with adequate means of transportation and storage, the present extraction could be somewhat over 300,000,000 bbl. a year. These enormous potential oil resources of the Veracruz coast proceed from a relatively small number of wells, scattered over a few oil fields, separated from each other by large unexplored areas, wherein may be found other favorable fields which, in time, will undoubtedly become just as great centers of oil production. Experts who know our Gulf Coast believe that lands with commercial oil resources lie not only between the Panuco amid Tuxpan Rivers, but that indications are that the oil zone of Mexico, with more or less interruption, takes in the coast zone from Northern Tamaulipas to the foot of the Sierra Madre of Chiapas, and the banks of the Usumacinta River. This generalization is not merely the outcome of optimism, but is the result of the persistency with which one finds, throughout this Gulf Coast, the most usual characteristics upon which we depend for recognizing oil-bearing lands.

Jan 5, 1918

By [Dipl. -Ing. ] Karl Angerer

The "New Austrian Tunneling Method" is one of the most significant developments in European tunneling in the last 15 years. I hope this report will show the significance of this tunneling method, which was developed in Austria exactly 18 years ago and which is now used in many European countries. In Austria from 1948 to 1953, the Moll tunnel with a length of 11.6 km (about 7.3 miles) was constructed as a part of the Kaprun power plant. Depth of overburden varied from 1000 to 1400 m, and there were many rock bursts in calcareous-schist formations. Here for the first time it was found that a thin concrete lining would help to prevent rock bursts if it was sprayed on the rock soon after blasting. During construction of the Prutz-Imst tunnel in Austria from 1953 to 1956, the shotcrete lining was sprayed on the phyllite surface a certain distance behind the blasting face to prevent rapid rock decomposition. This method was also tried in soft-rock sections of the tunnel where steel and wood supports usually were necessary. To prevent loosening of the rock, application of the sprayed concrete was tried immediately after blasting. This method made it possible to tunnel through very soft ground. Where necessary, the shotcrete was supplemented by steel arches and mesh reinforcement. At that time (1953-1956), the machines and equipment for guniting or spraying concrete were being improved rapidly and it became possible to spray aggregates up to 25 mm in diam. Hardening accelerators brought quicker strength and better adhesion of the shotcrete-this also made it possible to use the method in wet tunnels. If the tunnels are extremely wet or flowing with water, it is necessary to seal off the wet rock or drain the water, using, for instance, the Oberhasli method. After these first successful steps with the new Austrian method, large portions of the Schwarzach power plant in Austria were designed and built. At this operation, shotcrete was used almost exclusively for tunneling work. It was on this site where, for the first time, a tunnel 120 m long with a 45-sq- m section was driven through overburden without one piece of timber

Jan 1, 1970

By Richard H. Sillitoe

Gold is an important byproduct and, locally, coproduct of porphyry copper deposits, and possesses potential for discovery as the major metal in porphyry deposits in either island arcs or Cordilleran belts. Tungsten and tin occur as major components of several potentially bulk-minable porphyry deposits, as well as being byproducts from the Climax porphyry molybdenum deposit. Whereas porphyry tin systems are localized in Cordilleran back-arc settings, their tungsten counterparts appear to span a range of geotectonic settings, from Cordilleran principal arcs through back arcs to rifts. Although silver is a common byproduct of porphyry cop- per deposits, it tends to be preferentially concentrated with lead and zinc on the fringes of all types of porphyry deposits and/or as late-stage superpositions; the latter situation could be of some interest in the higher parts of porphyry systems. As byproducts, rhenium, uranium, platinoids, and magnetite are exploited occasionally, and rutile and the rare metals, such as tantalum and niobium, merit consideration.

Jan 1, 1983

By Dever Ashmead

ENGINEERS, operators, miners, and others di-rectly interested in mining will readily agree that more of well-directed illumination in mines will result in a reduction of accidents and general im-provement in the working conditions, comfort, and effi-ciency of those employed underground. Progress has been made in the amount of illumination from individual lamps carried by miners. The candle, which a great many of us can remember as the general method of lighting, was replaced by the oil lamp or torch, later by a specially prepared oil known as "Sunshine," and eventually by the carbide cap lamp. The metal mines still present a field for progress from the standpoint of general illumination, particular-ly those mines having high stopes. Attention is being more and more focussed upon the advantages of im-proved lighting in mines, in order that the underground employee may benefit as the factory workers have al-ready done. The management is vitally interested in the morale of its employees, the reduction of costly accidents and increased production, all of which, judging by results in other industries, will be sub-stantially benefitted through the means of improved general illumination. From data available to the writer, 40 to 50 per cent of the accidents in the metal mines occur at the face; they may be due to roof falls, movement of loose ore, loading of cans, handling of tools, etc. Very probably a large proportion of these accidents may be attributed to lack of light. If sufficient illumination had been present the employee could have seen what was happen-ing and taken the proper precautions. The introduc-tion of better illumination means better visibility, de-crease in accidents, and increase in efficiency.

Jan 6, 1928

By Guy Jordan

HIGH-IRON cements have a number of advantages over cements carrying little or no iron. The presence of iron in, Portland cement aids in the manufacture of the cement and also imparts certain advantageous physical properties to the finished product. In manufacture, the presence of iron lowers the fuel consumption, increases the ease of proper burning, and lessens the destructive action of the charge on the kiln refractories. In the finished cement the presence of iron reduces the expansion and contraction, adds strength, adds increased resistance to freezing and thawing, and increases the resistance of the cement to sea or sulphate waters. During the past few years the construction of numerous dams through-out the Southeast by the Tennessee Valley Authority has stimulated the production of high-iron cements. At present a great number of specifica-tions call for an iron cement, and the industry is supplying this demand with a Portland cement carrying approximately 5 per cent iron oxide. Several manufacturers are now making practically all of their cement of this type and a number of others manufacture it as a special cement over short periods to meet demands from the Tennessee Valley Authority and other buyers. The recent increase in the use of iron in Portland cement has created a market for iron products that previously was nonexistent. The chief sources of supply for the cement manufacturers at present are iron sand, iron sinter and slag, and ocher. The Copperhill mining district, Ten-nessee, supplies both iron sinter and slag for use in cement. The Carters-ville district supplies iron sand, ocher, and some iron resulting from the magnetic separation of iron from barite. The advantages of these products vary according to the chemical properties of the raw materials and the methods of handling used by the different manufacturers. Where the iron is to be handled by conveying belts and in hopper cars, the iron

Jan 1, 1939

By A. M. Johnson

Dewatering is a major operational cost at some mines. Under certain conditions, costs associated with water disposal may continue beyond the productive bye of the mine. For mines with mineralized waters, this is of special concern. Since 1974 experience has been gained from examination of a number of closed underground metal mines that exhibited drainage problems. It was observed, in certain cases, that had appropriate steps been taken prior to closure, the resulting drainage problems could have been largely avoided. Reclosure steps would have involved alteration to the 'plumbing system" of the mines; i.e., the drifts and crosscuts interconnecting the mine workings. This could have best been accomplished by the placement of bulkheads and/or selective drifting. In addition to reconfirming that hindsight is 20-20, a lesson learned from these case studies shows that a relatively simple hydrologic evaluation prior to mine closure may avoid a troublesome and costly drainage problem.

Jan 1, 1985

By Edwin Hopkins

The year of 1924, in Venezuela, has been one of especial interest. The figures for production marketed are not so impressive, but to the well-informed followers of the development, the ease with which this production has been obtained and with which it apparently can be increased at will merits most careful consideration. For several years, the oil world, especially in the financial centers, has been closely following the slow unfolding. of the' Venezuelan developments, which has been, and still is, one of the great pioneering achievements in the history of oil exploitation. Venezuela, from the first days of its recognition by geologists and financiers as a great future source of oil, has been a field for the enterprising vision of the larger capital groups. The laws of the country have been drafted with almost an inspired foresightedness that has favored the exploitation of the resources along constructive lines, which' has eliminated the irrational promotion schemes that accompany many of the oil developments in the United States. Developments have been exclusively in the hands of strong financial groups, who have followed a conservative policy with respect to the dissemination of detailed information concerning the geological findings and detailed production data. Within the last year, however, the rapid expansion of the production phase of the developments has been on such an important scale and has involved such a large and rapidly increasing personnel, that further restraint with respect to information of a general informative' nature can serve no useful purpose. Certainly, from the volume of references to Venezuelan oil affairs, which are now of almost weekly occurrence in the oil trade journals, the public must appreciate the fact that in Venezuela, and in the Maracaibo district in particular, a new oil region of the first magnitude is about to emerge from comparative obscurity and occupy a commanding position on the stage of world oil affairs.

Jan 3, 1925

By Eugene Guccione

FOREWORD-At the SME-AIME meeting in Las Vegas this year, the SME Publications Board and the MINING ENGINEERING Committee decided that a fitting way of celebrating the United States' bicentennial would be to publish an article in ME covering the great men in American mining. After some discussion as to the inclusion of financiers -men such as William Randolph Hearst, J. Pierpont Morgan, etc.-the group agreed that the feature should be restricted to the "nuts-and-bolt people," e.g., mining engineers, geologists, mineral processing engineers. Thus, from the AIME All Institute Honors roll and from the SME Awards list, the group chose these 11 historical figures: Herbert Hoover, Daniel C. Jackling, Henry Krumb, James Douglas, Rossiter W. Raymond, Hal W. Hardinge, Seeley W. Mudd, Erskine Ramsay, Howard N. Eavenson, Robert A. Richards, Arthur F. Taggart. What follows is an account of each of these great miners' achievements and the problems they faced, and an assessment by some of today's mining leaders of the challenges that lie ahead.

Jan 7, 1976

By John Griffen

THE modern anthracite breaker or washery uses almost completely a wet method of preparation, which requires, roughly, 1 gal. of water per minute per ton of production per day. The entire anthracite industry uses about 320,000 gal. per min. of water for this purpose or 800,000 tons of water per day. As this water leaves the breakers, it contains fine solids-coal, slate, pyrite, and clay-and is then called silt or slush; as slush is the term most commonly used, it will be employed throughout this paper. The solid content of the slush will be referred to as solids. In the earlier days of anthracite mining, little coal was washed, less crushing was employed, and virgin coal was mined exclusively. As a result, the slush problem was not acute because of the relatively small quantity and the coarseness of the solids. Such slush as was produced could usually be easily impounded and retained or could be discharged into streams without any appreciable pollution being apparent. The character of the fine waste from the breakers, changed materially as its quantity increased until now about 40,000 tons of slush solids are produced daily. Second mining and robbing operations materially increased the quantity of fine solids delivered to the breaker in the mine car. The demand for chestnut, stove and egg sizes, to the exclusion of grate, steamboat, and lump sizes, require finer crushing of the mine-run coal with a consequent increase of fine solids in slush. The use of rice and barley sizes removed a considerable tonnage of coarser solids from the slush but left great quantities of fine solids difficult to retain completely and store and long considered of no possible fuel value. Despite the efforts of the coal operators, the slush solids have found their way into the streams causing, in some cases, serious pollution. The Water Supply Commission of Pennsylvania published, in 1916, a report on Culm in the Streams of the Anthracite Region,1 from which the following is taken: About 40,000,000,000 gal. of water carrying 10,000,000 tons of fine culm are discharged into the water-courses direct, flushed into the mines, or disposed of by various means on the surface. The extent to which the very small sizes of anthracite

Jan 9, 1921