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By Walter R. Hibbard, Robert I. O’Herron, Fred D. Rosi, Howard T. Clark

INTRODUCTION AND PREVIOUS WORK IN the search to find a copper-base alloy with high strength properties, it was considered that the addition of a small amount of an age-hardening element to a binary system with useful strength properties might result in a series of alloys of theoretical and practical importance. [ ] The copper-nickel system was selected for its basic properties and chromium was added as the age-hardening element in view of the small percentage involved and its decreasing solubility with decreasing temperature. A study of the Cu-Cr binary alloys was undertaken as a preliminary investigation. However, in view of the response of these alloys to heat treatment, the scope of this phase of the investigation was widened. [ ]

Jan 1, 1948

By F. E. Jaumot, A. Sawatzky

IT as long been recognized that there is a need for accurate systematic data on diffusion in solids. Originally, such data were needed to check existing theories but, more recently, it would appear that it could be used most advantageously as a guide to, or a check for, much needed extensions of the theory of diffusion. The awareness of the conditions which are important to experimental accuracy, the availability of the materials for accurate experiments, and the techniques have improved to the extent that it would now seem to an experimentalist that, unless extensions of the theory are made which take into account the fundamental parameters of the atoms, the electrons, and the lattice in some detail, the field of diffusion will rapidly become an empirical or semi-empirical field. The present series of experiments was designed to provide accurate data on the diffusion of the elements of the IB and IIB subgroups in silver; that is, to provide data on the diffusion in silver of three face-centered-cubic elements with roughly similar chemical properties, but with different atomic or ionic sizes and, similarly, for three noncubic elements. The elements of these two subgroups have different valences, so that the data will not give any significant information on differences due to the crystal structure of the solute. The present paper reports data on the diffusion of copper and mercury in single crystals of silver; the data for the other elements of the IB and IIB subgroups were reported previously by the authors1'2 and by Tomizuka and Slifkin.8 Experiment The general technique used was identical to that previously described1,2 and will not be repeated here. In all cases, the sectioning technique and high specific activity isotopes" were used. The short half-life of Cu64 made decay corrections more important than for the other isotopes, and necessitated around the clock shifts while data were being taken. Each section was counted at least twice (as was true for all longer half-life isotopes) and a monitor was counted along with each sample. Data for the diffusion of mercury in silver are presented at a greater number of temperatures than for the other solutes. This is a result of two circumstances. First, six (of 30) samples had to be discarded because of pitting or recrystallization which occurred during the diffusion runs, even though the samples had sustained high temperature prediffusion anneals. Either of these was a very rare phenomenon in the other experiments, and their occurrence in this case is considered in more detail below. Second, the curves of the logarithm of the activity of the sections vs the square of the penetration deptht were, in general, quite good, but frequently seemed to show one point to have high activity and the next point to have slightly low activity in terms of the best straight line. When this occurred, there was remarkable regularity of the high-low sequence. In any event, the results, as far as diffusion coefficients are concerned, were not affected by this amalgam effect. In fact, the mercury data had the highest internal consistency of any of the data. Results Diffusion of Copper in Silver—-Diffusion runs were made at eight temperatures In the temperature range from 700° to 950°C, for times ranging from 5 to 45 hr. A linear curve of the logarithm or the activity vs the square of the penetration depth was obtained for all samples. Table I summarizes the results for individual samples and Fig. 1 gives a plot 02 the logarithm of the diffusion coefficients as

Jan 1, 1958

By H. M. Chance

The Choctaw coal-field is a direct westward extension of the Arkansas coal-field, but its coals are not like Arkansas coals, except in the country immediately adjoining the Arkansas line. From the base of the coal-bearing rocks up to the top of the coalmeasures, I find a total thickness of at least 8500 feet. This great mass of coal-bearing rocks consists of an alternation of slates, shales, sandstones and coal-beds, with their accompanying under-beds of fire-clay. Only one small bed of limestone was observed. This occurs near the middle of the series; it is about eighteen inches thick, and quite arenaceous. The formation is naturally subdivided by seven or eight thick beds of sandstone, varying from 50 to 200 feet in thickness, the outcropping edges of which form a series of more or less bold " hogback " ridges, the interbedded shales and slate forming the intervening valleys. The base of the coal-series is a massive sandstone, ranging from 100 to 200 feet or more in thickness, lying immediately beneath the Grady coal-bed, which is the lowest known coal. In the district embraced between. the Missouri, Kansas and Texas railroad and the Arkansas State line, this sand-rock usually forms a bold semi-mountainous ridge. This is the ridge through which the St. Louis and San Francisco railroad passes at Bryan station, where the Grady coal-bed is opened and worked, from which point it can be traced westward without difficulty, passing about three miles north of Le Flor on the same railroad, thence west to the " Little Narrows " (which is merely a gap in the ridge), 'and beyond to a point two miles west of the Thompson-McKinney place, where it swings abruptly north for a mile or more, only to resume immediately its westward course, forming for some miles the northern boundary of the valley known as the " Boiling-Springs Prairie," beyond which it trends somewhat

Jan 1, 1890

By Ralph H. Sweetser

OF SPECIAL importance in the design and construction of an iron blast-furnace plant are tile raw materials to be employed. Obviously the iron must come from some ore of that metal, but the many kinds available lead to important differences in plant arrangement, and in the design of furnaces and accessory equipment. For instance, the bulk of the gangue in the ore is subject to wide variation as is that of the ash in the fuel. A gradual increase in the bulk of raw material necessary to produce a ton of pig iron has been noted, but this has been more than offset, so far as costs of operation are concerned, by improvements in the machinery used for handling large quantities of ore. coal limestone, and slag. The mechanization of coal and iron-ore mining. the building of big ore boats and limestone carriers, of ore docks for fast loading and unloading, and the general use of heavy railroad equipment have all contributed to greatly reducing the number of man- hours required to mine, transport, and manufacture the raw materials into a ton of pig iron. This looks like a big saving and it is. If it were not for these big labor saving machines it would be impossible to produce the tonnage of iron and steel that is made each year in this country. On the other hand, the total capital investment necessary to bring down the man-hours per ton of pig iron to a 2.3 hours average at the blast furnace and to a total of only 12 man-hours from ore to metal (see Table 1) is so great that even the present high price of pig iron is probably not far above the true cost of manufacture when all the fixed charges are properly included.

Jan 1, 1939

By Stuart St. Clair

IN view of the great interest shown in the oil possibilities of Kentucky, one is impressed with the paucity of reliable literature on the oil fields of the state. A few brief reports by the Federal and State Geological Surveys are about the only reliable data available. When the estimated production figures, for 1918, are published by the U. S. Geological Survey, they will show a revival of the oil industry in the Blue Grass State during the past half decade. There will also be an increase in the production for 1919 and 1920, at least. Although as an oil-producing state Kentucky is small, compared with sonic of the other oil states, the present production and the area of undrilled proved territory is large enough to classify it as one of the important oil states of the Union. This paper will be confined to the Irvine District and the immediately adjoining areas which have been prospected with varying success. The Corniferous limestone or Irvine sand is the oil-producing formation in the area discussed.

Jan 7, 1919

By F. D. Rosi, Walter R. Hibbard, R. I. Herron, H. T. Clark, O&apos

Introduction and Previous Work In the search to find a copper-base alloy with high strength properties, it was considered that the addition of a small amount of an age-hardening element to a binary system with useful strength properties might result in a series of alloys of theeretical and practical importance. The copper-nickel system was selected for its basic properties and chromium was added as the age-hardening element in view of the small percentage involved and its decreasing solubility with decreasing temperature. A study of the Cu-Cr binary alloys was undertaken as a preliminary investigation. However, in view of the response of these alloys to heat treatment, the scope of this phase of the investigation was widened.

Jan 1, 1949

By Grafton Thrasher

For the proper discussion of this subject it is necessary to incorporate in this paper the substance of part of an article published by rite in Metallurgical and Chemical Engineering for January, 1915. CAST-IRON TEST PLUG, SHOWING LOW MOTTLED AND MOTTLED FRACTURES. Several years ago, while I was thief chemist for a malleable-iron company, it occurred to me that the mere regulation of silicon was not sufficient to produce the desired degree of chill. But only after repeatedly encountering this fact in befit open-hearth and air-furnace, as well as cupola metal, was I led to regard variation in the total carbon as the principal cause of disturbance; and I resolved to determine the total carbon as well as the sill on ill every heat, and by a carefully prepared test piece to gauge the approximate degree of chill. The test piece selected was a round plug, 2 in. in diameter and 12 in. long, cast on end

Jan 10, 1915

By AIME AIME

TWO papers, "Calcium, Strontium, and Barium Metals," by Charles Hardy and Paul M. Tyler, and "The Mining of Gems and Ornamental Stones by American Indians," by Sydney H. Ball, were presented before the Rare Minerals and Metals group at its session Tuesday afternoon in the Auditorium. Donald M. Liddell, chairman, presided. Mr. Tyler summarized the first paper, outlining the uses, history, occurrence, manufacture, production and trade, markets and prices of the three metals. In discussion, in response to the chairman's query on "what are they doing in Russia with calcium, strontium, and barium," Guy C. Riddell replied that nothing is being done on a production basis. The great rare metals plant in Moscow is active, however, on other elements. "They are making radium chloride, uranium oxide, vanadium, cadmium, tungsten, molybdenum, selenium, antimony compounds; and mercury, nickel and arsenic are under production at interior plants. The rare metals plant is busily conducting research on beryllium, rhenium, lithium, bismuth, strontium and zirconium. These are the main rare metal activities. Much hard-alloy work. for cutting and facing, is under way:

Jan 1, 1933

By W. L. Crentz, E. E. Donath, D. Doherty

Maurice Rey—The influence of cyclone diameter upon the fineness of separation is an important point which, however, cannot be discussed adequately if the injection pressure or the rate of flow are not specified. Perhaps some light can be thrown on the matter by using the formulas derived by Dahlstrom. Let us consider several geometrically similar cyclones where the apertures e and b are equal and proportional to the diameter D and which are operated with the same pressure drop. Eq 8 of Dahlstrom's paper can be written: Q Q = K D'. " or. if F is constant: Q = K D18 K is a constant of proportionality. Introducing this value of Q in eq 13 gives elimination efficiency = K D0' " Elimination efficiency, in the terminology of Dahlstrom, means the diameter of particles, in microns, which divide equally between the underflow and the overflow. This denomination is regrettable and it would be preferable to call it diameter of separation or characteristic size or any other name connoting a size rather than an efficiency. Whatever the name used, the above equation shows a slow increase in the fineness of separation when the diameter of the cyclone decreases. For example, if a 14-in. cyclone gives a 400-mesh separation (37 microns), geometrically similar cyclones, having the same pressure drop will give separations at the sizes shown below.

Jan 1, 1951

By E. E. Donath, W. L. Crentz, D. Doherty

Maurice Rey—The influence of cyclone diameter upon the fineness of separation is an important point which, however, cannot be discussed adequately if the injection pressure or the rate of flow are not specified. Perhaps some light can be thrown on the matter by using the formulas derived by Dahlstrom. Let us consider several geometrically similar cyclones where the apertures e and b are equal and proportional to the diameter D and which are operated with the same pressure drop. Eq 8 of Dahlstrom's paper can be written: Q Q = K D'. " or. if F is constant: Q = K D18 K is a constant of proportionality. Introducing this value of Q in eq 13 gives elimination efficiency = K D0' " Elimination efficiency, in the terminology of Dahlstrom, means the diameter of particles, in microns, which divide equally between the underflow and the overflow. This denomination is regrettable and it would be preferable to call it diameter of separation or characteristic size or any other name connoting a size rather than an efficiency. Whatever the name used, the above equation shows a slow increase in the fineness of separation when the diameter of the cyclone decreases. For example, if a 14-in. cyclone gives a 400-mesh separation (37 microns), geometrically similar cyclones, having the same pressure drop will give separations at the sizes shown below.

Jan 1, 1951

By James J. Bean

Although determining and controlling specific gravity of operating medium in a heavy-media plant manually presents no problem, there are advantages to automatic recording and control. The two installations discussed employ the usual method of measurement. Pneumatic control with band control and reset features is used to regulate dilution water and hence specific gravity. Difficulties have been mechanical in nature and associated with obtaining a proper I sample and maintaining tight air connections in bubble-tube piping:

Jan 1, 1950

By Henry P. Ehrlinger, James C. Bradbury

Tripoli is a naturally occurring, very finely divided form of silica found chiefly in some midwestern and southeastern states and used commercially as fillers and abrasives. Definitions Tripoli is a microcrystalline, finely particulate, more or less friable form of silica that appears to be the product of leaching of siliceous limestone or calcareous chert. The term was originally applied to a deposit near Seneca, MO, that resembled material of that name found near Tripoli In North Africa (Hovey, 1894). The two deposits were subsequently found to have different physical characteristics -the North African tripoli, now called tripolite, is a diatomite, composed of the siliceous skeletons of microscopic marine plants called diatoms; the Missouri tripoli contains no diatom remains. The term tripoli, however, continued to be used for the Missouri material and is now applied in a general way to most silica deposits similar to it in characteristics and geologic origin. In commercial trade tripoli is commonly understood to designate material from the Missouri-Oklahoma field; silica from southern Illinois, the other major producing area, is referred to commercially as amorphous silica. Each term, however, may be used commercially for material, regardless of place of origin, that has the characteristics or uses commonly ascribed to the material from one or the other major producing area. For example, in the commodity price listings, Engineering & Mining Journal routinely lists under Tripoli, prices "f.o.b. Elco, IL" and "f.o.b. Seneca, MO, and Rogers, AR," and under Silica, amorphous, prices "f.o.b. IL," and "f.o.b. bierks, AR." Amorphous silica, the commercial designation given to southern Illinois tripoli, is, like the term tripoli, a misnomer. Mineralogically, the southern Illinois deposits are composed of microcrystalline quartz, and no amorphous material has been detected during X-ray and scanning electron microscope investigations (Leamnson, Thomas, and Ehrlinger, 1969; Thomas et al., 1970; Keller, 1978). Soft silica is another term that has been applied to Illinois and Tennessee tripoli, presumably to distinguish it from the more compact Missouri material. It has also been used in the ceramic trade to distinguish tripoli from "hard" silica, or silica flour, produced by pulverizing silica sand (Heinz, 1937). Rottenstone, produced commercially in Pennsylvania, is similar to tripoli in that a major constituent is finely particulate silica, and its uses are much the same as those of Tripoli-as abrasives and fillers. The origin of rottenstone also is similar to that of tripoli-decomposition of a siliceous sedimentary rock. The parent rock is defined as a siliceous limestone (Gary, McAfee,, and Wolf, 1972; Thrush, 1968) or as shale. Heinz (1937) quotes a brief statement describing the Pennsylvania deposits -"a black impure shaly limestone grading into black shale"-but does not identify the source of the statement. For convenience, rottenstone is included with tripoli in the reporting of production statistics in US Bureau of Mines (USBM) Minerals Yearbooks. Other materials that have been called tripoli include siliceous deposits in San Bernardino County, California (USBM Minerals Yearbooks, 1934-1941) and in Nevada (Chandler, 1960). These, however, differ in composition and/or origin from tripoli and, therefore, should not be identified by the name tripoli.

Jan 1, 1983

“The mining industry can do more to alleviate world poverty, hunger and human misery, more to close the widening gap between advanced and developing nations and more to achieve international peace and understanding than any other single force in the world," Charles W. Court, Minister for Industrial Development, Western Australia, told the American Mining Congress audience at the opening session of the 1969 Mining Convention, October 19-22, San Francisco. Australia, he pointed out, is a shining example. In 1971, 60% of U.S. mining investment overseas will go to Australia and other parts of Oceania, an increase of 42% over a year ago. Australia has capitalized on world needs, its own rich resources and good investment climate. Developing nations can and should do the same, but they mix emotion with nationalism, often frightening away foreign investment which could breathe life into dormant and backward areas, said Court.

Jan 12, 1969

By Mark E. Smith

To allow recovery of gold values from ore which cannot be economically processed by the mill, Pinson Mining Company has developed a run-of-mine heap leaching facility. In order to estimate production scale recovery rates, reagent consumption and percolation problems, a series of pilot scale tests were performed. These tests typically consisted of 3,630 metric tons (mt) (4,000 tons) leach ore at a grade of .94 to 1.56 grams Au per metric ton (g/mt) (.03 to .05 oz. Au/ton). Test heaps were loader stacked to approximately 4.3 meters (14 feet) high. Information from these pilot scale tests was employed in the design and construction of the production scale facility. Parameters such as spray rate, leach cycle, sprinkler placement, and barren solution chemistry were determined by the pilot tests.

Jan 1, 1984

By David J. Selleck, Eugene P. Pfleider

9.61. Introduction. Open pit mining methods produce more than 80% of all raw materials today in the United States. Much of this comes either from properties that formerly employed underground methods and were converted to open pit or from mines that ultimately must go underground when the economic stripping limit is reached. Generally the ores are transported over large vertical distances and techniques have been developed to do this economically. One approach is to combine conventional surface trucking, over relatively level roads, with the use of gravity and underground facilities. There are various modifications, depending upon the character of the orebody and the topography. Several schemes, as used in Sweden, Canada, and the United States, merit describing. One of the critical problems involved in the transference of ores from surface to underground is that of flow of bulk solids. Must it be crushed? Will it hang up in the transfer? What size and inclination of ore pass are required. How is the ore best fed onto the transporting device underground? As an example, the planning engineers for the Carol Project of the Iron Ore Company of Canada faced these problems in making their designs for the production and transportation of some 55,000 tpd from their Smallwood Mine in Labrador. Other operations, facing somewhat similar conditions, used other approaches of interest. This chapter describes some of the factors involved in the design, construction, and operation of a combination surface underground transportation system as applied to open pit mining operations. 9.62. Tunnel-Ore Pass Systems. The type, shape, dip, and size of the orebody, as well as the surface topographic features, generally estab-

Jan 1, 1968

By Charles C. Hawes

DETERMINATION OF SILICA OXIDE iron ores usually are found in intimate association with silica and phosphorus compounds. Their quantitative separation and purification sometimes present difficult problems to the chemist. Silicic acids may represent various degrees of dehydration. They are exeedingly weak, but combine with metallic oxides and form some of the most stable oxides in nature, the silicates. When iron ores are treated with hydrochloric acid, they yield practically all their iron. However, apart from rare exceptions, varying amounts of insoluble residues of silica, alumina, lime, magnesia and compounds of phosphorus, sulphur, titanium, chromium and others will be left. If the oxides of silicon, aluminum and titanium are present in small quantities, the insoluble residue is generally very small, but the presence of these oxides is more usual in larger quantities. Therefore, only a special treatment can break the bond between these elements. Ore Residues Acids remove the soluble constituent of the ore, leaving the insoluble residue, which chemically is rock or gangue and must be treated accordingly. Alkali carbonates are used frequently to break up the residue, but other fluxes have also been recommended, such as a number of lead and boron salts. The introduction 0f these salts, which offers certain advantages, requires, however, their removal before the other constituents can be analyzed, and this elimination is sometimes difficult. Usually in quantitative analysis silicates are dissociated by fusing them in a platinum crucible with sodium carbonate, thereby forming sodium silicate, Na2SiO3, sodium aluminate, Na2Al204, sodium titanate, Na2TiO3, and carbonates of other elements. All the carbonates are soluble in hydrochloric acid, but also some silicic acid is formed that must be rendered insoluble. To this end the solution is evaporated several times, as the first evaporation still leaves as much as 5 per cent of the silica soluble. Even after a number of evaporations, minute quantities of silica may be found with the iron and alumina present. Perchloric Acid as an Agent for Dehydrating Silicic Acid Perchloric acid, HC104, (60 per cent), has been used for years as a solvent, but few chemists have used it to dehydrate silica. It is derived from anhydrous perchloric C1207, which is most unstable and dangerous. Perchloric acid is a strong oxidizing agent, which boils at 203°C. It is more effective in rendering silica insoluble than any other known agent, and most rapid in action. After perchloric acid is added to a mixture containing silicic acid, the resultant solution is

Jan 1, 1945

By Charles C. Hawes

DETERMINATION OF SILICA OXIDE iron ores usually are found in intimate association with silica and phosphorus compounds. Their quantitative separation and purification sometimes present difficult problems to the chemist. Silicic acids may represent various degrees of dehydration. They are exceedingly weak, but combine with metallic acids and form some of the most stable oxides in nature, the silicates. When iron ores are treated with hydrochloric acid, they yield practically all their iron. However, apart from rare exceptions, varying amounts of insoluble residues of silica, alumina, lime, magnesia and compounds of phosphorus, sulphur, titanium, chromium and others will be left. If the oxides of silicon, aluminum and titanium are present in small quantities, the insoluble residue is generally very small, but the presence of these oxides more usual in larger quantities. Therefore, only a special treatment can break the bond between these elements. Ore Residues Acids remove the soluble constituent of the ore, leaving the insoluble residue, which chemically is rock or gangue and must be treated accordingly. Alkali carbonates are used frequently to break up the residue, but other fluxes have also been recommended, such as a number of lead and boron salts. The introduction of these salts, which offers certain advantages, requires, however, their removal before the other constituents can be analyzed, and this elimination is sometimes difficult. Usually in quantitative analysis silicates are dissociated by fusing them in a platinum crucible with sodium carbonate, thereby forming sodium silicate, Na2SiO3, sodium aluminate, Na2A1204, sodium titanate, Na2TiOs, and carbonates of other elements. All the carbonates are soluble in hydrochloric acid, but also some silicic acid is formed that must be rendered insoluble. To this end the solution is evaporated several times, as the first evaporation still leaves as much as 5 per cent of the silica soluble. Even after a number of evaporations, minute quantities of silica may be found with the iron and alumina present. Perchloric Acid as an Agent for Dehydrating Silicic Acid Perchloric acid, HCI04, (60 per cent), has been used for years as a solvent, but few chemists have used it to dehydrate silica. It is derived from anhydrous perchloric C1207, which is most unstable and dangerous. Perchloric acid is a strong oxidizing agent, which boils at 203°C. It is more effective in rendering silica insoluble than any other known agent, and most rapid in action. After perchloric acid is added to a mixture containing silicic acid, the resultant solution is

Jan 1, 1945

By L. P. Teas

In spite of the influx of operators into the Gulf Coast anxious to retrieve their depleted production in other fields, and in spite of very active application of the most scientific geophysical methods to locate new producing areas, the results have been very discouraging and the year has failed to produce more than the average results for a Gulf Coast year. During the year seven new oil fields, some of which are still of very little importance, and one new gas area have been discovered. These fields are Tom Ball, Greta, Cleveland, Raisin and Garwood in Colorado County; Louise and Premont in Jim Wells County, and the new producing gas area near Ace in southern Polk County. During the year salt has been found for the first time at Carlos and Esperson. New producing areas have been developed on East Stratton Ridge, Hockley, Hull, Port Neches, near Pettus in Bee County, and on the O'Connor Ranch in Victoria County. The total production for the Gulf Coast for the year was 62,837,435 bbl., an increase of 18,589,000 bbl. over 1932. During the year, 1307 wells have been drilled of which 207 were wildcats, compared with 653 wells and 141 wildcats the previous year. The total daily production at the end of the year was 165,201 bbl. At present there are 3100 oil wells producing. The average production per well is 55.5 bbl. per day. The price of crude fluctuated considerably during the year, beginning at 80c per barrel and closing the year at $1.04 per barrel. Completion data for 1933 are as follows:

Jan 1, 1934

By Ernst M. Cohn

The demonstrations of the "Silent Sentry" by Union Carbide Corp. in 1957 and of a special tractor-plow by Allis-Chalmers in 1959 ushered in the technology era of fuel cells. The idea for direct conversion of chemical to electrical energy, first published in 1801 by Davy in England and Ritter in Germany, has been kept alive by a few people through 150 years: Grove built the first hydrogen-oxygen fuel cell in 1839; Mond and Langer made electrolyte contributions around 1890 that are still used today; Baur worked on coal-based cells from 1900; Bacon started his work in the '30's, which resulted in the first multi-kilowatt unit in the '50's; Davtyan studied molten-salt electrolytes in the '40's, followed by Ketelaar in the '50's; and Justi developed highly active electrodes in the '50's, to name only some of the pioneers. Despite the tremendous increase in research and development of fuel cells, these direct energy converters are still in their infancy. They will find their functional application in space, where power density must be maximized and product water utilized. These early systems will provide valuable experience in system engineering and reliability.

Jan 9, 1964

By B. VISWANATH

T HE Mysore iron works, at Bhadravati, about 2000 ft. above sea level in the Shimoga district of Mysore, British India, is served by a meter gage branch line of the Mysore State Railways. The works which were designed and erected by Perin & Marshall, who still act as consulting engineers, are surrounded by a thickly wooded country which sup- plies about 400 tons per day of wood for fuel. The ore deposits lie 20 miles to the south, and limestone quarries are close by the works. The Bhadra river sup- plies the works and the town with the necessary quantity of water. Dwelling houses for the employees

Jan 1, 1930