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By C. E. Birchenall, H. M. Schadel, G. Derge

EXISTING distribution data' for silicon between liquid iron and silver at steelmaking temperatures, 1500" to 1600°C, has made activity relationships in liquid silver-silicon alloys desirable as a method of determining the silicon activity in molten iron. To this end, through the use of radioactive Ag110 and the molecular beam technique described in a previous paper,' the vapor pressure of silver as a function of temperature has been measured over three silver-silicon alloys containing 3.9, 9.3, and 15.4 atomic pct (eutectic composition) silicon. The technique was that described for pure silver with the exception that a porcelain liner was used inside

Jan 1, 1951

By Albert F. J. Bordeaux

(Cleveland Meeting, October, 1912.) THE immediate vicinity of the sea-shore, affording special facility for the exportation of ores, makes it possible to work certain mines in the Vladivostok district, which, in more remote places of Siberia, would remain unproductive. Outside of the city of Vladivostok the population is small and the country is very little prospected. Additional discoveries of valuable deposits like the large body of calamine which has recently been opened in the neighborhood of earlier worked lead-silver ores, in the Tetiuhe valley, are still in the field of possibilities. For many years gold alone was produced, in part from the coastal rivers and in part from a quartz-vein on Askold island near Vladivostok. But the production is diminishing, and prospectors are looking for other rivers in the interior, such as the tributaries of the Ussuri. These rivers are now more accessible than formerly, due to the slow but gradual development, of colonization by the Russian peasants. The few natives of the country, called Orodjones, are of the Chinese race. They resemble the North American Indian and are hardy fur-hunters. They have given some attention to placers and have already shown good specimens of gold-dust from the rivers Iman, Bikin, Noto, etc. Coal-mining was begun in the Vladivostok region more than 20 years ago, but in a somewhat irregular way. The industry is not as yet important and the best coal-seams are badly prospected, or ire even neglected. Copper, lead, and iron exist in several places. The amounts give some encouragement to the anticipation that the discoveries will give rise to important metallurgical works. I here present a review of the various deposits, based upon such safe information as is in hand, when I have not drawn upon my personal observations. Fig. 1 is a snap of Eastern Siberia, showing the mineral deposits.

Oct 1, 1912

By Thomas Brownfield

Development and production activity in Oklahoma during the year 1940 was of routine nature. Production, according to the Corporation Commission's figures, averaged 409,100 bbl. daily as compared with 421,000 bbl. for the year 1939. Discoveries were of minor importance except for the Cumberland pool in Marshall and Bryan Counties, in the southern part of the state. Maintenance of a relatively stable producing rate is attributable to the drilling of new wells and the recompletion of many old wells in the previously established producing areas. During the year 1785 new wells were drilled, a decline of approximately 10 per cent as compared with the previous year. Of the wells drilled, 962 were oil wells with a combined initial production of 241,000 bbl. daily, 172 were gas wells having aggregate capacities of 1205 million cu. ft., and 651 were dry holes. Wildcat activity increased 20 per cent over 1939 and 227 such wells were completed during the year; that isl 43 oil wells, 16 gas wells, and 168 dry holes. In addition to the new work completed, 603 wells were recorded as having been drilled deeper or plugged back to test new horizons; included were 334 producing wells with total initial production of 65,000 bbl. daily, 37 gas wells with initial aggregating 305 million cu. ft., and 232 abandonments. Footage drilled amounted to 4,730,000 ft., an average of 2650 ft. per well as com-pared with an average depth of 2600 ft. recorded the previous year. The principal new pools discovered as a result of the exploratory drilling were Cumberland; East Cromwell, in Okfuskee County, and Prague, in Lincoln County. At the end of the year Cumberland had 13 completed wells, which averaged 700 bbl. initial through tubing from the Simpson Bromide formation (Ordovician) at 4750 ft. East Cromwell had 10 wells with average initial of 435 bbl. in the Cromwell sand (Pennsylvanian) at 3460 ft. Prague had II wells with an initial average of 220 bbl. from the Senora sand (Pennsylvanian) at 3260 ft. There were notable extensions to the Dill pool, Okfuskee County, and to the Hewitt pool, Carter County. At the end of the year, 19 producing wells had been drilled in the former, with initials averaging 1000 bbl., and 63 wells averaging 150 bbl. daily in the latter. There were no notable changes in the policy of State conservation authorities with respect to proration. The Bureau of Mines recommendations for the year averaged 413,000 bbl. daily; the State author-ities fixed allowables at an average of 406,000 bbl. daily, while, as noted above, production averaged 409,100 barrels. The most important development in the older areas occurred in the following pools: Billings.—Seven oil wells with an average initial production of 2500 bbl. and two dry holes were completed during the year. Production from the Simpson horizon averaged 6025 bbl. daily as compared with 5950 the previous year. Production from this field has been almost steady since reaching its peak early in 1937. The major portion of the pool is efficiently operated as

Jan 1, 1941

By Thomas Brownfield

Development and production activity in Oklahoma during the year 1940 was of routine nature. Production, according to the Corporation Commission's figures, averaged 409,100 bbl. daily as compared with 421,000 bbl. for the year 1939. Discoveries were of minor importance except for the Cumberland pool in Marshall and Bryan Counties, in the southern part of the state. Maintenance of a relatively stable producing rate is attributable to the drilling of new wells and the recompletion of many old wells in the previously established producing areas. During the year 1785 new wells were drilled, a decline of approximately 10 per cent as compared with the previous year. Of the wells drilled, 962 were oil wells with a combined initial production of 241,000 bbl. daily, 172 were gas wells having aggregate capacities of 1205 million cu. ft., and 651 were dry holes. Wildcat activity increased 20 per cent over 1939 and 227 such wells were completed during the year; that isl 43 oil wells, 16 gas wells, and 168 dry holes. In addition to the new work completed, 603 wells were recorded as having been drilled deeper or plugged back to test new horizons; included were 334 producing wells with total initial production of 65,000 bbl. daily, 37 gas wells with initial aggregating 305 million cu. ft., and 232 abandonments. Footage drilled amounted to 4,730,000 ft., an average of 2650 ft. per well as com-pared with an average depth of 2600 ft. recorded the previous year. The principal new pools discovered as a result of the exploratory drilling were Cumberland; East Cromwell, in Okfuskee County, and Prague, in Lincoln County. At the end of the year Cumberland had 13 completed wells, which averaged 700 bbl. initial through tubing from the Simpson Bromide formation (Ordovician) at 4750 ft. East Cromwell had 10 wells with average initial of 435 bbl. in the Cromwell sand (Pennsylvanian) at 3460 ft. Prague had II wells with an initial average of 220 bbl. from the Senora sand (Pennsylvanian) at 3260 ft. There were notable extensions to the Dill pool, Okfuskee County, and to the Hewitt pool, Carter County. At the end of the year, 19 producing wells had been drilled in the former, with initials averaging 1000 bbl., and 63 wells averaging 150 bbl. daily in the latter. There were no notable changes in the policy of State conservation authorities with respect to proration. The Bureau of Mines recommendations for the year averaged 413,000 bbl. daily; the State author-ities fixed allowables at an average of 406,000 bbl. daily, while, as noted above, production averaged 409,100 barrels. The most important development in the older areas occurred in the following pools: Billings.—Seven oil wells with an average initial production of 2500 bbl. and two dry holes were completed during the year. Production from the Simpson horizon averaged 6025 bbl. daily as compared with 5950 the previous year. Production from this field has been almost steady since reaching its peak early in 1937. The major portion of the pool is efficiently operated as

Jan 1, 1941

By R. S. Goodrich, G. S. Ansell

The microstructure of three Al-Al2O3 SAP-Type alloys (containing 2.0, 3.0, and 5.7 wt pct alumina, respectively) was studied utilizing transmission electron microscopy. These alloys were fabricated from aluminum powders by powder-metallurgical techniques, cold-rolled into thin strips, and recrys -tallized. Thin foils suitable for an electron-transmission study were then prepared from the strip material by electropolishing. The microstructure of these alloys is shown to consist of small (0.1 mean diameter) plate -shaped alumina particles finely distributed in an aluminum matrix. In the higher-oxide content alloys the platelets are somewhat larger and more irregular in shape. The distribution of oxide particles is not uniform and there is an increasing tendency toward clumping SINCE the discovery by Irmann1 that aluminum alloys produced by compacting, hot pressing, and extruding fine aluminum powders possess remarkable high-temperature mechanical properties, the Al-A12O3 SAP-Type alloys have been utilized extensively as model dispersion-strengthened alloys in both experimental and theoretical invest igations.2-8 The use of the SAP-Type alloys as model dispersion-strengthened alloys implicitly assumes that their microstructure has been completely delineated. This is, however, not the case. with increasing oxide content. In all the alloys studied, the mean center-to-center spacing of particles was quite small (0.2 u) due to the very fine oxide debris present. Selected-area diffraction of the specimen identified the oxide as either y Al2O3 or y' Al2o3. The re crystallized MD-5100 alloy exhibited a mean grain diameter of only 0.7u, while the grain size of the other alloys was several hundred microns. Severe pinning of the grain boundaries by oxide particles was rarely observed, and the grain boundary triple points in the small-grained MD-5100 alloy were often particle -free. Diffraction contrasts visible around the particles are attributed to elastic strain fields set up by differential thermal contraction during cooling from the recrystallization anneal. Early investigation demonstrated that optical metallography did not possess sufficient resolution to observe the microstructure of the SAP-Type alloys.' Later, extensive use was made of replication techniques to study the microstructure by means of electron microscopy.7-9 These studies indicated that the SAP-Type alloys consist of a dispertion of irregular Al2O3 platelets, approximately 150A thick 9 and a micron or so on edge,9 distributed in a matrix of commercial-purity aluminum. These oxide platelets tend to be oriented in the aluminum matrix, with their largest dimension parallel to the extrusion direction. 8,9 A study employing polarized-light techniques1' indicated that the grain size of a series of as-extruded SAP-Type alloys was several microns in diameter, while the grain size after re-crystallization was several millimeters in diameter. A more recent study 12 utilizing surface-replication techniques examined the particle morphology,

Jan 1, 1964

By E. A. Gulbransen, W. S. Wysong

The behavior of tungsten and its surface oxides in oxidizing and reducing atmospheres and in high vacua at elevated temperatures is a question of considerable technical importance. The use of tungsten as a a Or as an important component in alloys in high temperature Oxidizing atmospheres has been limited because of the unprotective nature of its oxide film and the volatility of its oxide. This paper will present results of a micro-balance study of the following problems: (1) the oxidation behavior in the ternperature range of 25 to 550°C (') the reduction with pure hydrogen Of thin Oxide films formed On tungsten, and (3) the volatility Of thin Oxide films On tungsten. Tungsten is an interesting metal to study for the following reasons: (1) although the Oxide to to ratio is greater than one, the oxide is not considered protective, ('1 the meta1 readily Oxidizes at temperatures from 30" to 55o°C (3) the oxides WO² and WO³ are reduced at temperatures as low as 500°C. by hydrogen, and (4) the Oxide WO3 is volatile at temperatures from 800 to 1100°C. Literature The oxidation of tungsten in its thin film range has not been studied critically. In the thick film range Dunn3 has made the only systematic study. He found the oxidation rate to obey the parabolic rate law in the temperature range of 700 to 900°c. The temperature variation of the oxidation rate constant was found to follow an exponential law of the Arrhenius type. An inflection was noticed in the temperature plot of the rate law constant at 850 to 900°C. This was attributed to a phase change in the oxides, Schei14 has studied the oxidation rate at 500 and 700°C over long periods of time and found a linear rate law. This result was interpreted as evidence for the presence of a nonprotective film. Pilling and Bed-worth's5 analyses of the oxide volume to metal volume ratio would indicate that a compact protective film should form. McAdam and Geil6 have studied the oxidation of tungsten in the thin film range using the interference color method. A parabolic rate law was found. Their curves showed that tungsten oxidizes faster than nickel but more slowly than iron. The lattice structures found in the oxidation of tungsten surfaces have been studied by Hickman and Gulbransen.? They have reported that WO3 is the stable oxide in contact with the metallic substrate up to approximately 600°C while wo³ forms first at 7oo°c. Hagg and Magneli8 have recently reported a study of the lattice structures . observed in the tungsten oxidcs using the X-ray diffraction method. In addition to an a-phase WO3 and a '-phase WO2, they reported the existence of two new phases. A 8' phase, homogeneous between

Jan 1, 1949

By A. U. Seybolt

DURING the course of experiments involving oxygen equilibrations with a high-purity Pd-5 at. pct Rh alloy, the appearance of a subscale was noted. Most of the heat treatments in a pure oxygen atmosphere were performed at 900°C. The presence of the subscale was noted when the oxygen partial pressure was in excess of approximately 95 mm, up to 1 atm, the highest pressure used. According to available thermodynamic information' on the free energy of formation of Rh2O3 (the only reliably reported solid oxide of rhodium), this oxide should not be stable under these conditions, nor, of course, any oxide of palladium. Extraction of the subscale from the matrix was affected by treatment with aqua regia, and the resulting X-ray diffraction powder pattern is shown in Table I. This pattern is not that of Rh2O3, nor that of any known rhodium or palladium oxide. It can be indexed on a hexagonal lattice with a. = 5.22Å and co = 6.0Å. In addition to this unknown material, there was a weak Rh2O3 pattern. An X-ray fluorescence analysis of the powder gave 3214 palladium counts per sec and 5381 rhodium counts per sec, thus indicating the likelihood of a double oxide of palladium and rhodium. In view of the fact that the above result was obtained on a single sample, it is perhaps best not to insist upon the above ratio of about 0.6, but possibly to tentatively assume 0.5 or 1/1. The small amount of Rh2O3 in the X-ray pattern might have occurred on cooling, and it seems possible that the double oxide, below some temperature level, is not as stable as Rh2O3. To examine this point, some of the extracted double oxide was heated on a sheet of pure palladium in air at 900°C, and allowed to furnace-cool over a period of several hours. The X-ray diffraction pattern of the powder showed approximately the same intensity of Rh2O3 and the "hexagonal" oxide as before, but, in addition, a rather faint pattern of another crystalline species made its appearance. This finding again suggests partial transformation of the major (double) oxide to other oxides on cooling from 900°C. Application of the phase rule shows that only one equilibrium oxide (subscale) could have been present at temperature. Vacuum-fusion, oxygen analysis of the extracted subscale showed 7.7 ± 0.7 pct O. Combining this information with that of the X-ray fluorescence analysis suggests the formula PdRhO. This compound should have an oxygen content of 7.07 pct, which is within the range of error of the oxygen analysis. However, until a more careful stoichiometric study is made, it is suggested that the formula be written

Jan 1, 1965

By D. H. Baldwin, R. E. Reed-Hill

DURING the course of experiments involving oxygen equilibrations with a high-purity Pd-5 at. pct Rh alloy, the appearance of a subscale was noted. Most of the heat treatments in a pure oxygen atmosphere were performed at 900°C. The presence of the subscale was noted when the oxygen partial pressure was in excess of approximately 95 mm, up to 1 atm, the highest pressure used. According to available thermodynamic information' on the free energy of formation of Rh2O3 (the only reliably reported solid oxide of rhodium), this oxide should not be stable under these conditions, nor, of course, any oxide of palladium. Extraction of the subscale from the matrix was affected by treatment with aqua regia, and the resulting X-ray diffraction powder pattern is shown in Table I. This pattern is not that of Rh2O3, nor that of any known rhodium or palladium oxide. It can be indexed on a hexagonal lattice with a. = 5.22Å and co = 6.0Å. In addition to this unknown material, there was a weak Rh2O3 pattern. An X-ray fluorescence analysis of the powder gave 3214 palladium counts per sec and 5381 rhodium counts per sec, thus indicating the likelihood of a double oxide of palladium and rhodium. In view of the fact that the above result was obtained on a single sample, it is perhaps best not to insist upon the above ratio of about 0.6, but possibly to tentatively assume 0.5 or 1/1. The small amount of Rh2O3 in the X-ray pattern might have occurred on cooling, and it seems possible that the double oxide, below some temperature level, is not as stable as Rh2O3. To examine this point, some of the extracted double oxide was heated on a sheet of pure palladium in air at 900°C, and allowed to furnace-cool over a period of several hours. The X-ray diffraction pattern of the powder showed approximately the same intensity of Rh2O3 and the "hexagonal" oxide as before, but, in addition, a rather faint pattern of another crystalline species made its appearance. This finding again suggests partial transformation of the major (double) oxide to other oxides on cooling from 900°C. Application of the phase rule shows that only one equilibrium oxide (subscale) could have been present at temperature. Vacuum-fusion, oxygen analysis of the extracted subscale showed 7.7 ± 0.7 pct O. Combining this information with that of the X-ray fluorescence analysis suggests the formula PdRhO. This compound should have an oxygen content of 7.07 pct, which is within the range of error of the oxygen analysis. However, until a more careful stoichiometric study is made, it is suggested that the formula be written

Jan 1, 1965

By William S. McAleer

Two major trends in the coal industry today focus attention on the need for heat-drying equipment of a simpler, more flexible and less expensive type than has been considered standard equipment for drying coal. These trends are: I. The tremendous growth in the use of mechanical equipment to load coal both in underground mining and strip mining, which necessitates efficient mechanical cleaning of the fine as well as the coarse coal and thus means a growing tonnage of washed fine coal? with its attendant moisture problems. 2. The growing consumer demand for the smaller sizes for use as domestic stoker coal, with increasingly rigid specifications covering size, ash, and moisture analyses. ACCEPTED PRACTICE In the past, when, for example, 4 in. too coal has been washed, there was little trouble in producing a washed product 4 to o with a satisfactory resultant moisture. The 4 to 3/8-in. could be taken from dewatering screens at a surface moisture ranging from 2.5 to 3.5 per cent, depending upon the size consist. The 3/8-in. to o coal was generally dewatered satisfactorily with centrifugal driers, to final surface moistures from 5.5 to 8 per cent, again depending upon size consist. The centrifugal type of drier has definitely proved itself to be the most economical type of machine to handle coal approximately 3/8 in. to o as recovered by dewatering screens or drainage elevators with 15 to 25 per cent surface moisture and turn out a product with moistures as stated above. Sometimes such moistures (5.5 to 8.0 per cent) in the product are satisfactory. If not, an ultimate moisture, lower than 3 per cent, is seldom required and the centrifugal drier removes 70 to 85 per cent of the total moisture to be removed. In certain districts there has been a growing tendency to circumvent the use of centrifugals or other types of driers, by dewatering over screens of the wedge wire type and wasting all the finer sizes. Sometimes all the minus 28-mesh has been wasted and often the size wasted has been as large as 1/8-in. By wasting these finer sizes, a lower moisture can be obtained in the finished product, but taking into account the cost of the tonnage so lost, plus the added cost of ultimately disposing of this wasted tonnage, often the cost will be greater than the cost of heat-drying in a modern plant, which makes possible the recovery of all the tonnage. Moreover, with the moisture standards for domestic stoker equipment even these wasteful approaches to its solution do not solve the problem and there remains only the alternative of heat-drying. HEAT-DRYING Until about four years ago, heat-drying of coal at the preparation plants was confined chiefly to drying the fine sizes (approximately 3/8 in. to 0). Occasional

Jan 1, 1941

By Waldemar Lindgren

IN spite of a world production of lead amounting to 1,300,000 tons, of which the United States produces slightly less than one-half, it appears that the mines at present are hardly able to supply the demand. For this there are several reasons. The lead deposits, geologically speaking, were formed comparatively near the surface under conditions of lower temperatures, with the richer deposits often residuary; that is, enriched by surface water, and consequently soon exhausted. Lead is practically absent from a great part of the world. The great Canadian shield, the eastern part of the Dominion, contains practically none. Scandinavia contains no lead. It is absent from geo- logical formations of great age, but does occur in large quantities in the deposits in the Rocky Mountain region. These deposits are, more or less directly, of igneous origin, but here, too, there is a tendency of the lead shoots to concentrate in the upper part, and when they go down the deposits turn to zinc-copper and some other metals. This is one of the best established facts of economic geology. The deposits of the Mississippi Valley district, from Kansas-Oklahoma, to Canada, are in comparatively accessible limestone beds, at a depth seldom more than 500 ft. Therefore, the lead is easily mined but more easily exhausted.

Jan 1, 1926

By HAROLD A. KNIGHT

The Miami Copper Co., Arizona, is asking Congress to reimpose the import duty of two cents per pound on copper which, by law, has been suspended until June 30, 1950. C. Donald Dallas, chairman of Revere Copper and Brass, champion of a duty-free regime as regards the red metal, has been answering E. H. Westlake, Miami president, now that Mr. Westlake's statement to stock- holders has been salted away for posterity on wire recorders. Even prior to this action and at the instigation of two prominent consumers of pig lead, the House of Representatives has, in the confines of committee, not yet reported out, as of June 16, a bill to suspend the duty on lead for another year from expiration of the present law June 30, 1949. But apparently the bill was started too late. Thus the tariff issue becomes a Rip Van Winkle again after having slept for several years in the mountains of metals scarcity. During the wartime scarcity and the boom days that followed, most metal producers welcomed a considerable influx of foreign metal since it gave them a little surcease from constant teleibhone calls asking why that delivery of 300 tons of lead, 250 tons of zinc, and 1000 tons of copper had been delayed. These were the days when it was such an undisputed sellers' market that the sellers had even thrown away their certificates of ownership. Another development that brings home the tariff situation, small in it- self but perhaps indicating a trend, has been the announced closing of

Jan 1, 1949

By L. W. Blau

RESEARCH work in exploration and production was further reduced during 1943 owing, partly, to difficulties in the acquisition of apparatus and, principally, to the exodus of research men to governmental agencies conducting research and to the armed forces.

Jan 1, 1944

By R. W. Raymond

ALEXANDER BRINTON COXE was born in Philadelphia, Pa., Jan. 19, 1838, the second of five sons of lion. Charles Sidney Core and Ann Maria Brinton. A more extended history of his family and its important relations to the development of the United States will be found in my Biographical Notice of his younger brother, Eckley B. Coxe, published in 1895. It is therefore sufficient to say here that Dr. Daniel Coxe, a distinguished physician and surgeon of London, and a medical attendant of Charles II and Queen Anne, purchased, in 1684 and 1686, lands in East and West Jersey from grantees of the Duke of York, and became Governor of West Jersey, in which capacity he did much to develop the provincial fisheries, the manufacture of marine salt and pottery, the exportation of tim¬ber and the West India trade. In 1698, having acquired the royal patent of the Province of " Carolana," covering (with some reservations) the territory extending from the Atlantic to the Pacific, between the 31st and 36th parallels of N. latitude, Gov. Cole sent an expedition from Charleston, S. C., to the Mississippi. In 1769, seventy years later, his grandchildren surrendered to the Crown their title under this vast and vague patent, receiving in return a grant of 100,000 acres in the Colony of New York. The line of his descendants, so far as they concern this sketch, is as follows 1. Col. Daniel Core, his son, b. 1673, who came to New Jersey in 1700; resided there until his death (1730); held many high offices; and issued in London (1722) A Description of the Provinces of Carolana, containing probably the earliest published plan of political union for the British Colonies in North America.

Sep 1, 1906

By AIME AIME

ON Tuesday afternoon, Feb. 17, a large and interested audience gathered in the auditorium of the Engineering Societies building to take part in the gold supply symposium that had been arranged for by the Mining Geology Committee. Waldemar Lindgren presided over the gathering and after brief introductory remarks on the international situation as regards lead, silver and gold, called on John Wellington Finch to present an oral abstract of the paper, "Sources and Trends in Gold Production," by R. J. Grant, director of the Mint, and. J. B. Knaebel. This ' paper reviewed the gold production of the world, by countries, since 1845, from the statistical viewpoint, leaving to the later speakers discussion of the statistics.

Jan 1, 1931

A. H. Bromly, Zihuatanejo, Guerrero, Mexico (communication to the Secretary*):—The following criticism of what "is offered as a summary which may be found useful by mining engineers," is not dictated by any captious spirit, but in the intereet of historical and scientific accuracy. The States of Queretaro and Oaxaca have produced sufficient silver to warrant more extended notice. Referring to Pachuca, State of Hidalgo, the eomewhat loose and inexact statement is made that "the ore-depdsit is an andesite, intermixed with quartz-veins, rich from the surface." A better description mould be,—the ore-deposits consist of quartz-veins in andesite. It is notable that many of the rich shoots worked in recent days did not come to surface. In consequence, Pachuca is often quoted by the ill-informed as a camp in which values improve with depth, the truth being that the veins carry shoots, or clavos, some of which were exposed at surface and some not. The name of " electric plow," applied to the mechanical stirrer of recent use, is certainly not to be recommended. The stirrer, or agitator, consists essentially of a traversing gang-plow, operated by power through shafting; drums, and wire-rope. The fact that in certain plants the motive-power used is electricity does not make it an electric plow. Such a name suggests a machine of which the motor is an essential and integral part; which is not so in this case. A lathe in a factory driven by water-power is not called a hydraulic lathe. My experience agrees with Dr. Raymond's note as to azulapue, which in some districts is also applied to blue copper carbonate. The El Oro, Esperanza, and Mexico mines should be allocated to the State of Mexico; the Dos Estrellas being in Michoacan, as stated. The El Oro quartz certainly does not appeal to me

Jan 1, 1910

By AIME AIME

FOR the mineral industry, as for many others, the year 1944 brought to fruition the seeds planted in previous war years. Accomplishment in attaining ends in the production of minerals has given more time for the consideration of postwar problems, such as plans for resuming production for civilian uses and measures to prevent possible mass unemployment. The hectic atmosphere in production circles lessened during the latter half of 1943, conditions becoming static during 1944 as peak production rates were reached. Withdrawal of deferment of young men from the mining districts by Selective Service connotes that man power at the battlefronts became more important than the persistence of pressure for metal production. This is in contrast to the return of soldiers in 1943 to augment the labor ranks in the mining districts. The year ended in the midst of changing needs. Over-all metal production in the United States in 1944 will record a lessening, compared with the previous year owing to labor shortages which affected both development work and ore output.

Jan 1, 1945

By W. R. Barclay

IN MY general contact with industry I have become more and more impressed with the need for the closest possible co-operation between engineers and metallurgists, and particularly with the need for appreciation of the work that each group is doing to assist the other. Also, I am convinced that from time to time it. is vitally important to a true perspective of human progress in all its branches, and certainly a salutary corrective of undue optimism and pessimism to endeavor to carry the mind hack over certain periods in the advance of technical knowledge, and form some kind of broad estimate of what has been accomplished in the application of science to industry in the fields with which we, as individuals or groups, may for the time being be concerned. We cannot without some appreciable mental effort realize what our forerunners have dine For us. If the young engineer or metallurgist entering industry today could be suddenly transported to a quarter of a century ago, and be compelled to work with the materials then available and within the limitations of knowledge then attained, he would, on his return to present-day life, have a much greater appreciation of what has been accomplished before lie arrived on the scene, and, what is even more important, a far more acute sense of its inherent value to his profession. I propose here merely to indulge in a general summary of the subject of improved engineering metals and alloys rather than in details, and to deal exclusively with developments within my own experience.

Jan 1, 1938

By Richard Addison, Ronald O. Cranor

Tailings dam construction and operation of Rosario Dominicana's gold/silver mine in the Dominican Republic is described. Impoundment of 8.5 kt/d of cyanide-process tailings is required in an intensive agricultural area which is also an earthquake and high rainfall zone. The earthfill embankment dam, incorporating internal gravel drains, is described together with methods of construction used. Methods of tailings transport, solution reclaim, and runoff water diversion that have evolved are discussed.

Jan 1, 1982

By William J., Coulter

IN the early days of Colorado mining, between 1880 and 1900, when Leadville, Kokomo, and Robinson were boom mining camps, the entire area around Climax for a matter of fifteen miles was overrun with prospectors, so the mineralized outcrop at Climax was not unknown. The principal interest in minerals during this period was in gold, silver, and lead, and since the Climax outcrop showed none of these it drew little attention. Geology played an important part in bringing prospectors to the very edge of the Climax deposit. The Mosquito fault, which crosses near the base of Bartlett Mountain, continues as an important geological structure, at least as far as Leadville some twelve miles distant, and at the base of Bartlett Mountain the vertical throw on the fault is estimated to be between 2000 and 5000 ft. The sedimentary beds known to the Leadville district are all present on Bartlett Mountain to the north of the Mosquito fault, which cuts them off abruptly, and exposes the Pre-Cambrian rocks that underlaid them, so the prospectors, who were searching for gold, silver, and lead in the sediments

Jan 1, 1946

By M. Guney, A. R. Bell

In Mindola mine on the Zambian Copperbelt, there is a plan to extend the current production level of 1.2- 1.5 km (3,900-4,900 ft) with five additional production levels. Research work indicated that the present total heat output of 38.6 MW will inevitably increase to 63.2 MW in 25 years. Estimated WE and DB temperatures, representing the total heat generation in stope faces and development headings during these same periods are predicted to increase to 33.8/40.2°C (93/104°F) and 35.3/42.1°C (95/108°F) respectively. It is assessed that the nominal refrigeration capacity needs to be progressively increased to 9,000 M W.

Jan 1, 1984