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By T. T. Quirke, L. C. McCabe

The object of the present investigation was to discover a physical basis for rank differentiation of coals, particularly the coals of the Illinois basin. Vitrainl was selected as the most appropriate coal material to use in the investigation, because of its homogeneity and ease of acquisition and handling. Previous Investigations.—Hoffman and Jenker2 have shown that their index of reflection is a characteristic of coal rank and that the Leitz slit microphotometer may be used in determining the different intensities of reflection. Zhemchuzhnikov3 measured the luster of several Russian coals with a color analyzer and found that the degree of luster was indicative of rank. Luster-volatile matter curves based on data from Sucan and Donetz coals were satisfactorily used for determining the rank or volatile content of other coals after the luster strength was determined. In 1934 Fisher4 reported refractive indices of 1.76 for bituminous vitrain and 1.87 for semibituminous vitrain. Investigation of Angle of Polarization.—Early in the present investigation several determinations of the refractive indices of the vitrains were made by immersing the minus 150 plus 200-mesh powder in oils. It was found that all the samples fell within the range 1.6 to 1.8. However, difficulty was encountered in securing oils in this high index range that were closely enough spaced to separate some of the coals. The writers made a number of determinations of the angle of maximum polarization from the polished surfaces of the vitrains and derived their refractive indices by the procedure described in the following paragraphs. Johannsen5 states the fundamental concepts underlying this procedure as follows: In general, in an isotropic medium light vibrates in all directions at right angles to the direction of propagation, and when it meets with another isotropic medium at an angle, part of the light is reflected and part refracted. It has been found that after reflection or refraction, the vibrations do not move with the same freedom in every

Jan 1, 1938

By Sir Robert A. Hadfield

The Hadfield method of producing sound steel ingots has been the subject of a paper read before the Iron and Steel Institute, so that it will be unnecessary to describe it fully here. The object of the method is to make poseible the production of steel ingots in which the pipe is almost entirely obliterated, and it is applicable particularly to the production of sound ingots, from which good rails could be rolled. The method in brief consists in casting the ingots on cars, usually with the small end down. Each ingot mold is provided with a sand top, rammed up in the well-known manner. After the mold is filled to the desired height with steel, a layer of slag about 0.5 in. thick is placed upon it and the balance of the mold is then filled with charcoal. Then, through suitable piping, an air blast is directed in numerous jets upon the charcoal, which is burned thereby, the combustion supplying addi, tional heat to the top of the ingot, which helps to keep the top fluid and to retard its solidification, while the lower parts are rapidly losing heat by its transfer to the mold. By one plan the ingots are cast in molds placed upon bogies, movable trucks, or platforms, in the position A, Fig. 1. The ingots are cast vertically on bogies, say four or more ingots on each bogie, as may be found most convenient, and the upper surface of the steel is maintained in a molten condition during the transit of the ingots from the casting pit to the stripper. This is effected by a series of air pipes, for example, three in number, with jets or holes on the under surface of such pipes, placed preferably horizontally, arranged in such a manner as to cause jets of air to impinge on the upper surface of the ingots. These holes or jets are made throughout the entire length of the overhead pipes, the length of such pipes being

Jan 1, 1914

By Major N. R. Junner

Although manganese-garnets are rarely seen in hand specimens of the manganese ores and associated rocks, they have been detected by the writer in thin sections of all the ores and wall rocks that have been sliced, with the single exception of the Insuta deposit. Rhodonite, and an almost colorless amphibole, which appears to be manganiferous, are less common. Types of Occurrence (a) Rocks Composed of Manganese-garnet and Quartz The best known examples of this type are from near Bole and Wa in the Northern Territories of the Gold Coast, and from near Chama in the Gold Coast Colony. Normally these are fine and even-grained rocks, in which the garnets cannot be recognized in hand specimens. They are often stained with secondary manganese oxide. Thin sections examined microscopically are seen to be composed of aggregates of minute crystals of garnet in a matrix of mosaic quartz. Some manganese oxide and braumite (?) is often present, but other minerals are exceptional. The relative proportions of garnet and quartz in these rocks vary greatly and there is a complete gradation from quartz-rock to garnet-rock. (6) Rocks Composed Mainly of Manganese-garnet and Manganese Oxides Rocks of this type are known from Kalimbi Hill near Siripe, Pabini Hill near Bangwon, near Odumase and Konongo, and in the Ya Ya creek, about 5 miles east of Dunkwa. These are usually fine-grained banded dark-colored rocks, composed of abundant minute garnets in a matrix of black manganese oxide and braunite (?). A little microcrystalline is often present, and occasionally a little colorless amphibole. quartz (c) Rocks Composed of Rhodonite and Manganese-garnet Rocks of this type are not common. They are known from near Chama, and from the road between Senyong and Mangkuma. Some quartz is usually present. All these rocks resemble closely in texture and composition certain rocks from India, described by Fermorl as "gondite;" and they also resemble certain rocks described by Derby2 from the Queluz district,

Jan 1, 1927

Shoveling ore cost so much at Tyrone during the year 1917 that it was deemed advisable to conduct tests to see where the fault lay. These tests were in the nature of time studies and extended over a period of very nearly a year. No data were available on this work to supply a starting point, so it was necessary to begin in a very elementary way, to find out the capacity of the average Mexican laborer. To' obtain a basis for comparison, it was necessary to determine the capacity of various types and sizes of shovels, so as to know whether the 21-1b. (9.5-kg.) load was the best load underground as well as on surface. A list of essential factors influencing shoveling was also made out during the course of a short series of preliminary time studies, and the motions involved in shoveling were analyzed and subdivided for convenience in studying. The necessary forms and record sheets were also decided upon at this time. A second short series of tests was then conducted on the surface, so as to be able to estimate the negative effects of underground work on the shovelers, and to minimize, as far as possible, the need for studying obviously poor types and sizes of shovels under the difficult conditions to be encountered in the mine. The test work underground consumed by far the greater proportion of the time and was divided into three series: Shoveling directly into a chute; shoveling into a wheelbarrow and tramming to a chute; and shoveling into a car and tramming to a chute. In each series the following points were determined for various lengths of time worked: Number of shovelfuls handled per minute, effect of distance thrown on shoveling speed, amount of rest required, amount of time consumed in tramming and dumping, proportion of working day occupied in shoveling, total tonnage handled during various working periods, effect of distance on tonnage handled during the day.

Jan 2, 1919

By T. O. Massalski, J. D. Ayers

A massive transformation, 0 —am, takes place in a number of copper-based systems where the ß phase field at high temperatures extends to compositions that are slightly less solute-rich than the limits of the a phase field that exists at lower temperatures. Consequently a solid-state transformation becomes possible that does not involve a change of composition. Within this narrow range of composition the massive am phase can be usually produced in two ways: by a fast quench from the ß phase through the a phase field, or by pulse heating into the a phase field of an undecomposed ß phase retained at room temperature by a prior quench. In the Cu-Ga system the occurrence of a massive am phase has been also observed in alloys whose composition falls outside the equilibrium a phase field1 but not in the Cu-Zn system.2 We have recently observed the occurrence of the ß — am transformation also in two silver-based systems, Ag-Zn and Ag-Cd. The a and 0 phase fields in these systems again slightly "overlap" in a narrow composition range. In the Ag-Zn system this range falls between 36.7 and 40.2 at. pct Zn, and in the Ag-Cd system between approximately 41 and 42.5 at. pct Cd. Alloys were prepared from high-purity materials and cast in quartz tubes under inert atmosphere. No significant change of composition occurred during casting. After homogenizing in the 0 phase field, small pieces of each alloy were reheated at the homogenizing temperatures for a few minutes and quenched into various media. There were examined metallographic-ally after removal of surface layers that may have suffered from contamination or from the loss of the solute element. In the Ag-Zn system extensive areas of the am phase (identified by selective etching, observation of the slip trace variants, and occurrence of twinning) were observed in a comparatively low-zinc alloy (37.8 at. pct Zn) for all quenching media employed: iced

Jan 1, 1969

By H. Scott

IN a paper read before the Institute of Metals, Rosenhain 1 described a new type of furnace designed primarily for the thermal analysis of metals by the inverse-rate method and used by him in the metallurgical department of the National Physical Laboratory with considerable success. In his discussion of this furnace, Rosenhain pointed out some difficulties met with in its operation, such as uniformity of rate of heating or cooling being inadequate for the degree of accuracy aimed at. To overcome this difficulty, he suggested, in place of motor propulsion, a gravity drive controlled by a"hydraulic cylinder with a relief valve whose width of opening can he regulated to allow of any desired rate of motion." The authors, in constructing a thermal-analysis furnace of Rosenhain's type, have therefore followed this suggestion and also added certain features that increase somewhat the convenience and simplicity of its operation. Requests for information regarding this furnace and the highly satisfactory results obtained from its use, it is believed, justify describing its construction and operation in sufficient detail to make possible its duplication or improvement. Description of Furnace.-The details of the furnace construction are shown in Fig. 1, which is drawn to scale. The heating tube is of /4 in. (6.35 mm.) wall "alundum" heated at the upper end by seventeen turns of 0.52 mm. platinum wire, which is coated with "alundum" cement supplied for this purpose. The cement coating is essential when a high temperature (over 1000° C.) is required, as it prevents hot spots with the resulting burning out of the heater. This platinum-wire winding, unlike "nichrome," is entirely satisfactory for temperatures of at least 1000° C. It has been maintained at that temperature continuously for 2 months and shows no signs of deterioration. This temperature is maintained by a current of 5 amp. drawn from 30 volts potential, so its necessarily continuous operation is quite economical.

Jan 8, 1919

By W. E. Wrather

The overproduction of crude oil in 1927 has received such widespread publicity, both within and without the industry, and the several factors which have brought about this situation are so thoroughly agreed upon by everyone, that it is unlikely the writer will in this brief review be able to contribute anything new. The entire story of low prices and demoralization revolves around two flush districts, Seminole and West Texas— the actual. performance of Seminole and the potential threat of West, Texas. The sustained production of California has been a contributing factor to this situation also. It seems reasonably certain that Seminole and West Texas will together dominate the industry during 1928, with Seminole probably destined to drop into second place, as additional pipe lines are completed into West Texas to care for its rapidly expanding production. It now appears inevitable that the production of 1928 will equal or exceed that of the past year, depending solely upon the rapidity wit,h which it is possible to market West Texas crude, and the degree of restraint which operators are willing to impose upon themselves in holding proved reserves of oil underground. Adversity has cultivated the growth of a promising spirit of cooperation which has accomplished practical results both at Seminole and in West Texas. Cooperation among oil producers has long been ardently hoped for, but prior to the past year it has never been effective on an important scale. The interests both of the industry and the public at large can best be conserved by cooperation in controlling production, and the widespread acceptance of this idea has paved the way for a more rational policy in the immediate future Production BY Major Districts The domestic production of the United States during 1927 amounted to 894,43.5,000 bbl. (Bureau of Mines), an increase over 1926 of approximately 128,000,000 bbl. California succeeded in maintaining its position of the past four years at 230,000,000 hbl. In 1923 with the Los Angeles

Jan 1, 1928

By J. N. Hobstetter, J. J. Becker

Slip lines in deformed copper single crystals exhibit very pronounced cross-slip and clustering if the stress axes are not too far from <100>. This orientation dependence seems to persist whether or not attempts are made to reduce the bending constraints of ordinary mechanical tests. THE purpose of this paper is to report some microscopic features of the plastic deformation of copper single crystals. The material used was OFHC copper obtained from the American Brass Co. Single crystals about 3 in. long and 5/16 in. in diameter were made by lowering graphite crucibles containing this copper out of the hot zone of a vertical tubular furnace at a rate of 1 1/4 in. per hr. The furnace atmosphere was nitrogen. The orientations of the crystals were determined by the back-reflection Laue technique.&apos; The X-ray spots usually indicated a slight lineage structure of not more than a degree or two. The crystallography of slip is discussed in Schmid and Boas.&apos; The terms classical slip, cross-slip, and conjugate slip are used here with the same meanings as in ref. 3. Compression Specimen 17 (Fig. 1) was selected because the resolved shearing stresses on eight slip systems dif- fered at most by a factor of 1.2. It was hoped that in this situation such effects as cross-slip might be made more prominent. Two intersecting planes parallel to the stress axis were ground on the crystal, using optical abrasive on a lead lap. The large plane was approximately perpendicular to the plane of the axis and the primary slip direction. Its exact orientation was determined by X-ray. The smaller made an angle of 49" with the larger, measured by reflecting a small light source. The specimen was etched with nitric acid until its diameter had been reduced 0.010 in., and then was given a metallographic polish and very

Jan 1, 1954

By James D. Sisler

Among the various studies made by the Coal Fact Finding Commission, appointed by President Warren G. Harding in 1922 to investigate all phases of the coal-mining industry in the United States and to report to Congress, was one concerning the amount and nature of losses in mining bituminous coal in the eastern part of the United States. This study was carried on under the direction of the U. S. Bureau of Mines. The writer was appointed field engineer to investigate the problem in Ohio, Pennsylvania and West Virginia. Some 400 mines were studied in these three states and conclusions were drawn from many sources of data. The summary report written by George S. Rice and J. W. Paul states that "the field reports indicate that the recovery in Ohio will remain about as at present, except in the Belmont district; whereas in Pennsylvania it will gradually improve, and in West Virginia it will improve rapidly." Since 1922, the writer has been interested in gathering material to substantiate or contradict these prophecies. Nature of Coal Losses There are six general causes of losses of coal in mining: (1) coal left on the roof and bottom; (2) coal lost in room, entry and panel pillars; (3) coal lost in oil-well or gas-well pillars; (4) coal lost under buildings, railroads and boundaries; (5) coal lost in handling and prepayation, underground and surface; (6) coal lost by rolls, thin or dirty areas and under streams. Local economic aspects that dominate the type of mining conditions determine to some extent whether certain losses are avoidable or unavoidable. In general, however, unavoidable losses include coal lost in the protection of buildings, streams, railroads, restricted properties and around oil and gas wells. Barrier pillars and other safety pillars are unavoidable losses as long as their size does not exceed the minimum for adequate safety. Natural physical conditions beyond human control, such as rock faults, clay veins, partings and binders, bad top and bottom, rolls and horsebacks, cause unavoidable losses. Unavoidable losses

Jan 1, 1931

By P. B. Scotland

THE mines of the Arizona Copper Co. are situated in the Morenci-Metcalf copper district in southeastern Arizona. This copper-bearing district covers a triangular mountainous area of about 3 square miles, rising abruptly from the gravel plateau of the surrounding country. In this area, an immense intrusion of porphyry has displaced, shattered, and engulfed the shales, limestones, and quartzites formerly bedded on the basal granite. Outcrops of oxide ore were discovered in 1873, and these surface ores were found to connect in depth with large bodies of high-grade oxide ores in the limestones and shales. The smelting of these ores in blast furnaces continued until about 1893, when the rapid exhaustion of the high-grade ore led to the discovery and exploitation of the low-grade sulphide ores in the adjoining porphyry. Methods of concentration were then devised and the low-grade ores finally rendered profitable. The Arizona Copper Co. and the Detroit Copper Mining Co., operating in the same district, were the pioneers in the successful development of the low-grade "porphyry" properties of to-day. The largest mines of the Arizona Copper Co. are the Humboldt and Clay at Morenci, and the Coronado, Metcalf, and King at Metcalf. These mines produce about 4,000 tons daily of concentrating ore containing from 2.5 to 2.8 per cent. copper. The topography of the country is very rugged and mining operations are conducted principally through adit levels. A few of the mines are opened by shafts, the deepest being 1,100 ft., in the Coronado mine. ORE OCCURRENCE The low-grade sulphide ore occurs as: (1) disseminated deposits in the main stock of quartz porphyry; (2) lode deposits in fault fissures in granite. The high-grade oxide ores were found as tabular deposits in limestone and shale close to contacts with porphyry. Low-grade oxide ore formed the outcrop of some-&apos; the sulphide orebodies; the majority of the outcrops, however, were barren.

Jan 2, 1915

By J. S. Levine

A series of four displacement experiments has been run in a large alundum core. Flow potential distribution in each liquid phase was measured continuously through oil-wet and water-wet capillary barriers, using a null-point pressure balance, and saturated distribution was determined from electrical resistivity measurements. A method has been devised for calculating the effective (and relative) permeability to each phase at any time and at any point in the flow system for the transient displacement process. Relative permeability points have been calculated and average curves drawn for oil displacing water and water displacing oil. The values of dynamic capillary pressure have also been determined. Data have been substituted into the generalized Buckley-Leverett fractional flow equation and a comparison between actual and theoretical breakthrough recoveries is shown. Displacement experiments have been performed in the laboratory for many years in an effort to determine the effect of a number of parameters on multiphase flow in porous materials. In the literature of petroleum technology, Wyckoff and Botset&apos; were among the first to develop the relative permeability concept and to show experimentally that oil, gas, and water can flow simultaneously through a porous medium in a precise way governed by certain fluid properties, by the relative saturation of each fluid, and by characteristics of the medium itself. Somewhat later, Leverett2 and Hassler, Brunner, and Deahl11 developed some theoretical concepts of capillary behavior in porous materials. The work of Buckley and Leverett3 presented a theoretical analysis of immiscible liquid displacement based on the equation of continuity and the Darcy equation for viscous flow of each fluid. Subsequent investigators attempting to verify the Buckley-Leverett equation have, in general, deliberately neglected the capillary pressure term or have performed experiments in such a manner that it could be neglected. Terwilliger, et al4 in 1951, obtained agreement between theory and experiment for the constant rate displacement of water by gas in a long vertical sand column. Rapoport and Leas5 have investigated the

Jan 1, 1955

On August 4, 1844, J. C. Fremont made the first record found of coal in Wyoming. On the North Fork of the Platte River, beyond Medicine Butte, in Carbon County, he noted: "in the precipitous bluffs were displayed a succession of strata containing fossil, vegetable remains, and several beds of coal. In some of the beds, the coal did not appear to be perfectly mineralized; and in some of the seams, it was compact and remarkably lustrous." A little later he noted, "longitude 111°, latitude 4 1/2°-Muddy R.--coal."1 In 1848, Clayton reported coal on Sulphur Creek near the site of old Bear River City, in Uinta County.2 Maj. Osborne Cross in his journal, on July 1, 1849, records seeing coal on Deer Creek and in one of the hills near Crooked Muddy Creek, in Converse County; on July 7, he records that the country from Deer Creek to the Sweetwater River abounds in coal, probably in Natrona and Carbon Counties.3 A letter from Asst. Quartermaster Van Vliet to General Jessup dated July 25, 1850, asked an appropriation for building shops at Fort Laramie for making repairs for the emigrants, and mentions "coal and timber," but undoubtedly meant charcoal, as no other mention of stone coal is made in the records of the fort.4 Stansbury, in 1852, placed on his map of this section the words: "Great Coal Basin," extending from the west bank of Bear River, near the present Evanston, to Point of Rocks in Sweetwater County. In 1859, a military coal reservation was established near here, but the coal was never worked to any great extent, although probably some was hauled to Fort Bridger for smithing purposes. When the fort was abandoned this reservation returned to the public lands .2 In the same year (1859), Hayden traced the lignite formation uninterruptedly from the upper Missouri Valley to a point on the North Platte River, about 80 miles northwest of Fort Laramie.5 On August 25, 1865,

Jan 1, 1942

By Norman F. Patton

The subject assigned is so broad that thorough discussion is well-nigh impossible within the space allotted, and further, few specific data are available upon which to predicate conclusions concerning the efficiency of present methods of distributing anthracite. This paper treats briefly the various agencies through which both primary and secondary distribution are effected, the methods of transportation and the general interrelation of production, demand, inventories and price. Avenues of Distribution Three distinct types of primary distribution are common in the marketing of anthracite. First, though not most important, is the sale by the producer, or operator, direct to the consumer. These sales, other than to employees and the local trade, are generally confined to steam sizes for industrial uses, and are consigned to the sidings or docks of the consumer. Sales of this type often are so closely priced to compete with oil and bituminous that the addition of even a small dealer&apos;s margin is sufficient to increase the cost to the point where the business might be lost. Second, the operator sells to a wholesaler or broker for subsequent resale, either to a retail dealer for clearance through his yard or direct to large consumers. Usually this method of distribution is employed by the smaller operators, who do not find it economically feasible to maintain extensive sales organizations. In most instances, the wholesaler retains some 5 per cent for his services, paid, of course, by the producing company whose anthracite he handles. He may, and frequently does, handle the output of several different companies, suited to the varying needs of the different communities he serves. His business includes all sizes of anthracite. The third, and by far the most general method, consists in selling to retail dealers, shipments being made direct from the breakers to the yards of the dealers. In large consuming areas, such as the metropolitan districts of New York or Philadelphia, one operator may sell to several

Jan 1, 1936

By Norman F. Patton

The subject assigned is so broad that thorough discussion is well-nigh impossible within the space allotted, and further, few specific data are available upon which to predicate conclusions concerning the efficiency of present methods of distributing anthracite. This paper treats briefly the various agencies through which both primary and secondary distribution are effected, the methods of transportation and the general interrelation of production, demand, inventories and price. Avenues of Distribution Three distinct types of primary distribution are common in the marketing of anthracite. First, though not most important, is the sale by the producer, or operator, direct to the consumer. These sales, other than to employees and the local trade, are generally confined to steam sizes for industrial uses, and are consigned to the sidings or docks of the consumer. Sales of this type often are so closely priced to compete with oil and bituminous that the addition of even a small dealer&apos;s margin is sufficient to increase the cost to the point where the business might be lost. Second, the operator sells to a wholesaler or broker for subsequent resale, either to a retail dealer for clearance through his yard or direct to large consumers. Usually this method of distribution is employed by the smaller operators, who do not find it economically feasible to maintain extensive sales organizations. In most instances, the wholesaler retains some 5 per cent for his services, paid, of course, by the producing company whose anthracite he handles. He may, and frequently does, handle the output of several different companies, suited to the varying needs of the different communities he serves. His business includes all sizes of anthracite. The third, and by far the most general method, consists in selling to retail dealers, shipments being made direct from the breakers to the yards of the dealers. In large consuming areas, such as the metropolitan districts of New York or Philadelphia, one operator may sell to several

Jan 1, 1936

By G. Czupryna, S. Natansohn

Electrowinning is the prevalent technique for recovering silver from wastes generated in silver-tungsten electrical contact fabrication. Such scrap is placed in a permeable plastic basket, which constitutes the anode compartment, and is suspended in a larger cell where the cathode is mounted. A silver nitrate solution is used as the electrolyte and, upon application of an electric field, the silver migrates to the cathode where it deposits. At times, there is tungsten migration to the cathode compartment and consequent co-deposition with the silver. This W contamination, which may amount to several thousand mg/L (oz per gal), necessitates additional purification of the deposited Ag and its removal would, therefore, be advantageous. Eliminating the W impurity also extends the operating period of the cell with corresponding increases in the Ag output and savings in labor costs. The solution to this problem lies in the selective removal of the W from the AgNO3 electrolyte either by liquid-liquid or liquid-solid extraction. Although W extraction in the liquid-liquid mode with a quaternary amine or other reagents as extractants appears feasible, particularly in view of the low pH (about 1.5) of the system, this approach was not considered because it is essentially a batch-type process. It is a more elaborate industrial operation than extraction by ion exchange resins. Implementing the latter process consists of passing the electrolyte from the electrowinning cell through an ion exchange column which would extract the tungsten selectively and returning the tungsten-free stream to the cathode compartment. This process continues until the W extraction efficiency decreases (as a result of resin loading) below an acceptable value. The electrolyte is then directed through another, similar column while the W values are eluted off the first one and the resin is regenerated for another cycle. Thus, two columns in a parallel flow pattern provide the means for continuous processing of the electrolyte feedstock.

Jan 1, 1984

By Donald L. Katz

Charts for predicting the pressure to which natural gases may be expanded without hydrate formation have been prepared for gases of even gravity. Pressure-temperature curves for hydrate formation were established for gases having gravities from 0.6 to 1.0. These curves and the thermal behavior of the gases during free and adiabatic expansion were used to prepare the charts for estimating the permissible expansion of natural gases without hydrate formation. The problem was solved by L. F, Albright, W. T. Boyd, J. J. McKetta, G. Martin, P. Poettman. and A. P. Snyder.-, who are first-year graduate students in the department of Chemical and Metallurgical Engineering at the University of Michigan. This paper is essentially a summary of their results. Prediction of Conditions for Hydrate Formation in Natural Gases Each natural gas under a given pressure will form solid hydrates at a corresponding temperature provided sufficient water is present.1-5 The temperature of natural gases below about 5000 lb. per sq. in. decreases when the gases are expanded freely.6,7 This decrease in temperature may cause the expanding gas to enter the region of temperature and pressure at which hydrates will form&apos; The final pressure to which a natural gas may &apos;be expanded without hydrate formation depends upon the initial temperature and pressure and the gas composition. This paper presents charts that give the final pressures to which gases of gravity 0.6 to 1.0 at given initial temperatures and pressures may be expanded without formation of hydrate. Hydrate-forming Temperatures and Pressures as a Function OF Gas -Gravity Experimental data of pressure versus temperature at which solid hydrate will form, provided sufficient water is present, are available for a series of gases.2,3 A method of predicting the pressure-temperature curve for a given gas composition has been reported.&apos; The solution to this problem requires that these curves relating pressure to temperature be established for gases of given gravities.

Jan 1, 1945

By J. Stubbins

1 1.4-1. Source of Water. Precipitation in the form of rain or snow is the original source of water that enters most surface mines. The precipitation, which does not escape to the atmosphere, either becomes surface run- off or infiltrates into the ground to become ground water (3,4). Evaporation and surface run-off can be measured. The water that infiltrates the ground disappears from view and is more difficult to evaluate. In general, it moves in a pattern similar to the surface run-off, but at a much slower rate, since its progress is impeded by many subsurface conditions. The infiltrating water descends through the soil and rock by whatever passageways permit flow until the water table or top of the zone of saturation is reached. Though usually pictured as a level surface, it is dependent upon the topography and the permeability of the enclosing material, and therefore it can be as erratic and unpredictable as the subsurface geology. Ground water may become surface run-off again at a lower point, and likewise, surface run-off of lakes and streams can infiltrate to become ground water. Should the ground water be confined to a permeable zone overlain by an impermeable barrier, a pressure is created. Such water is said to be artesian if the pressure head is sufficient to raise the confined water to the surface. These conditions are more commonly found in relatively flat-lying bedded formations. 11.4-2. Recognition and Estimation of Water. Dewatering and flood control should be considered by the design engineer at an early stage in all surface mine planning. Recognition of the possible problems, and making allowance for their solution, is an inexpensive precaution. Circumstances which should lead to investigation are: 1. High rainfall 2. Experience of other mines in the area 3. Evidence of water and caving in drill holes 4. Presence of springs and artesian wells 5. Geological evidence of aquifers.

Jan 1, 1968

By Leland Van Wert

IN 1888, Howard,1 working at the Watertown Arsenal on the tensile properties of ferrous materials at various temperatures, noted the curious fact that the stress-strain diagrams of low-carbon steels tested within a certain temperature range (200° to 350° C.) departed more or less from the normal regularity of such diagrams as secured by testing at either above or below these temperatures. This same jagged appearance of similar diagrams for steels has been observed by at least one other investigator, and de Forest2 has reported similar irregularities in the tensile testing of some nonferrous alloys. Recently again, this anomaly in diagram contour has been shown in a most striking fashion, apparently because of its accentuation by the method of testing employed, by Dr. Albert Sauveur.3 He described (for nonaustenitic steels) two quite distinct types of torsional stress-time diagrams: (1) those with a regular and smooth outline, derived normally by testing at temperatures above 300° C., or below 200° C. (as, for example, Figs. 4a or e); and (2) those presenting a decided "stepped" appearance, which are invariably produced when twisting is done within the 200° to 300° C. range (examples, Figs. 5a and b). The torsion test brings out so much more sharply (and convincingly) the irregularities occurring at 200° and 300° C. than does the tensile test that they can no longer be considered as resulting from simply idiosyncratic or accidental and inconsequential causes. Clearly, from the temperatures involved, the "stepped" type of diagram, or more accurately, the peculiar manner of response to torsional stress which manifests itself in the diagram, is an aspect of the "blue-heat" phenomenon. One&apos;s curiosity if, nothing else, prompts an inquiry as to the nature and significance of these "steps." What do they mean? What causes them? To these questions there are no completely satisfactory answers. The following experimental observations are offered as suggestions towards the solution of the problem.

Jan 1, 1931

By E. E. Malouf

With the continued development of low-grade porphyry copper deposits by open pit mining, substantial amounts of copper-bearing strip material have been accumulated in waste dumps adjacent to the many large mines. Since the end of World War II, the production of copper from leaching these copper-bearing wastes increased from approximately 4% of the total copper production to 10% by the early 1960&apos;s. Projected increases will probably raise this figure to 20 to 30% by the early 1970&apos;s. Furthermore, a gradual recognition of the economic feasibility of leaching mined-out areas is evident and will undoubtedly contribute additional production. Waste dumps in canyons and gulches on the periphery of open pit mines, mine stopes, caved areas, and abandoned open pits often contain substantial quantities of leachable rock ranging in concentration from 0.1 to 0.4% copper. Recent developments in the leaching of copper, mainly the recognition of bacterial oxidation of sulfide minerals combined with better under- standing of the control of the salt content of the leach solutions, both by adjusting the pH and/or by hydrolysis, are resulting in a greatly expanded recovery of copper from these hitherto uneconomic mine rejects. 11.5-1. Mechanism of Leaching. Leaching processes for the extraction of metal values from mine ore or waste may be classified for convenience as either chemical leaching or bacterial leaching. Chemical leaching is considered to be the extraction of soluble salts by metathesis in acidic, basic, or neutral water solutions. The reactions involved may be evaluated by chemical thermodynamics. Bacterial leaching, although a chemical process, is dependent on biological catalysis and this is generally a much more complex process. This justifies its separate treatment in the application to leaching. Acid ferric sulfate solutions are commonly employed in the mining industry to leach valuable metals from metal sulfide ores. The leaching mechanism is a reduction-oxidation reaction in which minerals are oxidized at the expense of ferric sulfate. Such chemical leaching is profitable when

Jan 1, 1968

By John Jermain Porter

The chief purpose of this paper is to indicate the laws governing the fuel-economy of the cupola, to examine the feasibility of some of the proposals for increasing its fuel-economy, and to show that the conditions limiting fuel-economy here are altogether different from those prevailing in the blast-furnace. The two methods available for studying the thermal efficiency of the cupola and determining the factors limiting fuel-economy are: 1, by the determination of the total heat-balance; and 2, by the application of the theory of critical temperatures. The case selected as an example represents a cupola operating under fairly efficient conditions. The data are as follows : Cupola, GO in. in diameter, 15 ft. high to the charging-door, with a 9-in. lining. Bed-charge, 2,000 lb. of coke and 4,000 lb. of iron. Subsequent charges, 400 lb. of coke and 4,000 Ib. of iron. Total number of charges, 20. There was 800 lb. of coke recovered from the drop, hence the total coke burned is 8,800 lb., or 0.11 lb. of coke per Ib. of iron. Coke contains 90 per cent. of fixed carbon and 2 per cent. of moisture. 300 1b. of kindling-wood is used in lighting. 80 lb. of limestone (95 per cent. of CaCO,) is used per charge, or 0.02 lb. per Ib. of iron. Melting-loss, 4 per cent.; distributed thus : Fe, 3.5; Si, 0.25; Mn, 0.25 per cent. Average analysis of top-gases : CO2, 15.1; CO, 10.0 per cent. Average temperature of top-gases, 1,600" F. Temperature of air and stock charged, 60" F. Dew-point of air, 50 F. The items entering into the total heat-balance and their calculation are as follows: 1. Heat of combustion of fuel.—Total heat evolved = 14,580 x lb. of carbon burned + 7,200 X Ib. of wood burned. Hence B.t.u. per lb. of iron charged =

Jan 1, 1913