Search Documents

By A. Andreas

New Mexico established an annual record by producing 38,897,741 bbl. of oil during 1940. This was approximately 6 per cent greater than the 1939 production of 36,746,840 bbl. The daily average produc-tion was 106,569 bbl. New Mexico retained its position as the seventh oil-producing state. The recommendations of the United States Bureau of Mines were followed by the Oil Conservation Commission in setting the monthly state allowable. At the beginning of the year the average top allowable for each qc-acre unit was 40 bbl. and at the close of the year it was 36 bbl. Remedial work by the operators has been extremely beneficial and satisfactory in reducing the gas-oil ratios in various fields. Gas formerly blown into the air is now being processed by numerous casinghead plants. The Oil Conservation Commission, with the full cooperation of the Proration Office and operators, has taken bottom-hole pressure surveys and has done considerable remedial work in various fields. Two new oil fields and one gas field were discovered in New Mexico during 1940. Numerous extensions to the existing fields were made. Some of these were definitely wildcats in the same townships designated as fields and some, although called extensions, were more than 3 miles from production. Lea County continued to be the largest oil-producing county in the state, with a production of 33,976,394 bbl. It had the largest number of completions during 1940, with 303 oil wells, 9 gas wells and 13 dry holes—a total of 325 wells. Eddy County was the next most active county, with 239 completions, of which 163 were oil wells, 8 gas wells and 68 dry holes. It produced 4,405,158 bbl. of oil during the year. The increased activity in Eddy County and the completion of a large number of producing oil wells have created a transportation problem that can be solved only by additional pipe-line facilities. During the year Eddy County was unable to produce 1,500,000 bbl. of its allowable oil, because there was no pipe-line outlet. There were 601 wells completed in New Mexico in 1940, of which 478 were oil wells, 22 gas wells and IOI dry holes. This was a decline of approximately 9.5 per cent in the number of completions compared with 1939, when 659 wells were drilled. Southeastern New Mexico Lea County.—The largest producing field in Lea County was the Monument field, with 6,894,475 bbl.; followed by Eunice with 6,559,348 bbl. and Vacuum with 4,743,065 bbl. The Hobbs pool, which for years was the largest producing field in the state of New Mexico, was fourth with 3,790,477 bbl. The Vacuum pool was the most active area, having 68 completions, of which 67 were oil wells and one was a dry hole. Only one new field was discovered in Lea County during 1940; the discovery well was in the Caprock area, the Livermore State No. I, in the SE. 1/4 SE. 1/4 sec. 30, T. 12 S, R. 32 E. This well was drilled to a

Jan 1, 1941

By J. Wade Watkins, E. S. Mardock

The accurate evaluation of reservoir-performance characteristics in the secondary recovery of petroleum by water flooding requires use of a water tracer that may be injected into water-input wells and detected at oil-production wells to supplement data obtained from core analyses, wellhead tests, and subsurface measurements. Radioactive iodine has been used successfully as a water tracer in field tests to determine: (I) relative rates and patterns of flow of injected water between water-input and oil-production wells and (2) zones of excessive water entry into oil-production wells. Laboratory evaluations of potential water tracers, previous tracer studies, the value of using a radioactive tracer, general field procedures, and the use of surface and subsurface instruments for the detection of the emitted gamma radiation, are summarized. Data from the field tests are presented graphically and discussed in detail. It is concluded that the radioactive-tracer method, using radioactive iodine, may be used successfully to measure either the relative rates and patterns of flow or zones of excessive water entry into wells under conditions of comparatively rapid transit time between wells. INTRODUCTION Extensive use is made of data obtained from core analyses, wellhead tests, fluid characteristics, and subsurface measurements in evaluating the sweep efficiency of water injected into oil sands for the recovery of oil. Theoretical flow rates and patterns may be calculated from those data using radial-flow formulas, if it is assumed that the physical conditions in the productive formation are homogeneous. Unfortunately, homogeneous conditions rarely, if ever, exist in oil-productive formations. The use of a tracer that may be injected into an oil sand and detected quantitatively, or even qualitatively, at offsetting oil-production wells provides basic data that may be used in determining more accurately the subsurface rates and patterns of flow of injected water between wells than is possible by theoretical calculations based on assumed conditions. Consideration of the data obtained by using a water tracer assists in the application of remedial measures to water-input wells, such as plugging of channels, or selective plugging of highly permeable zones, thereby effecting a more uniform flood and a greater ultimate oil recovery. A water tracer should have the following characteristics: (1) low adsorption on solid reservoir material; (2) high solubility in water; (3) low or negligible solubility in crude petroleum; (4) a wide range of solubility of compounds that may be formed by chemical reactions with ions present in reservoir rocks or waters; (5) high detectability in low concentrations by portable apparatus; and (6) general availability at low cost. Additional desirable characteristics are that the tracer should be nonhazardous in nature under normal working conditions and quantitatively detectable in the well bore, as well as at the surface. Review of Previous Tracer Studies The need for a water tracer has been recognized for many years. As far back as 1906, Dole1 described the use of fluorescein in flow-rate studies made in France in 1901. In 1921, Ambrose" discussed in detail the use of organic and inorganic dyes, chlorides, nitrates, and other anions, lithium salts, and the Slichter electrical

Jan 1, 1955

By Manuel Eissler

INTRODUCTION THE history of copper metallurgy in Japan goes back into remote ages, of this there is abundant proof, and that the working of this metal is closely connected with the artistic development of this nation is evidenced by some of the glorious monuments which have been produced by these ancient metal workers. The traveler sees to-clay in a perfect state of preservation bronze statues 150 ft. high, and over, 300 ft. in width, and 170 ft. in depth, delicately chased and beautifully marked, and when one reflects that some of them date back to the eighth century A. D., the question naturally suggests itself, how did these ancient metallurgists with their crude and primitive appliances accomplish this stupendous task? The bodies of these images are formed of bronze castings 10 to 12 in. thick, which were gradually built up and soldered together, but other pieces of magnitude, like the heads and other portions of the body are single castings. In many cases another method of construction must have been adopted. The walls of the molds were gradually built up and as the lower portion of the castings cooled, the walls were raised higher and higher and fresh metal must have been added, instead of constructing the whole mold first and then making the casting in one piece. There are still traces of substantial gilding visible on these statues, and how the pious Buddhist priests who were the constructors of them got the precious metal, is preserved in legendary tales.

Jan 11, 1914

By David H. Browne

The trite maxim that man is a tool-using animal might nowa-days be amended by saying that man is a tool-choosing animal. The chipped flint, at first all-sufficient, gave way to hammered bronze, and that, in turn, to wrought-iron and steel. As our knowledge of metals increases, we learn to specialize; we temper and anneal; we alloy and intermix; and we fashion for ourselves a metal suitable to our necessities. The knowledge of the properties and uses of the various metals and their alloys has become the capital of every constructive engineer, and the currency of every intelligent brass-founder aid blacksmith. Prom year to year, the specifications of the designer become more rigid, and the steel-maker is forced to study more closely the qualities obtainable by changing the treatment, or altering the composition, of his metal. Of making alloys there is no end. We have heard much, during the last decade, of manganese-steel and chrome-steel, of aluminum and tungsten, of titanium- and silicon- and copper-steels, and of every conceivable union into which steel could be coerced or cajoled. Without denying to each of these alloys novel and valuable properties, it. must be admitted that, of all alloys, the one which shows the greatest range of adaptability, and has met the largest measure of popular approval, is nickel-steel. Introduced to public notice by Mr. Riley, in 1889, its field of usefulness has been rapidly enlarged, until, at the present day, the use of nickel-steel is as thoroughly recognized as that of carbon- or manganese-steel. Concerning the properties of nickel-steel numerous articles have appeared in the technical journals. For the man in a hurry, who wishes to look up the properties and limitations of nickel-steel, these articles might almost as well be in the lost

Jan 1, 1900

By Noel H. Stearn

To the successful functioning of the geomagnetic method of exploration in engineering and geological practice there are two prime prerequisites : the measurability and the interpretability of significant magnetic anomalies. A magnetic anomaly may be defined as a permanent distortion of the earth's magnetic field, in order to distinguish it frog the distortions, either cyclic or irregular, which vary with time. So far as known, time fluctations have no directly assignable geologic significance in terms of rock formations, while anomalies may be considered to be directly caused by the difference in the magnetic properties within and between the formations of the substances that make up the earth's outer shell. As is effectively pointed out by L. B. Slichter,1 the effects which these differences produce on the magnetic field may be extremely minute or extremely great, depending upon the magnetic properties of the formations. Thus the actual anomalies may range from the infinitesimal to a magnitude considerably greater than that of the earth's field. The geomagnetic method of exploration has shared in the deluge of experimental effort which has lately swept geophysical prospecting to its present important place in engineering and geologic practice. But to date more of this effort has been expended upon the measurability of anomalies than upon their interpretability. The tendency has been to strive for the development of instruments and especially field techniques capable of measuring minute anomalies with a precision far beyond that for which there can be any hope of adequate interpretation other than as interesting phenomena having numerous possible causes. Such efforts, of course, are highly commendable in the field of so-called pure science, which includes the accumulation of undigested detailed observations and admits of interpretation by multiple hypotheses, but in engineering practice the factor of economy must enter. Those instruments and techniques are most desirable which can most rapidly measure the interpretable range of anomalies with the precision necessary

Jan 1, 1932

By John B. Baker, Bernard B. Betty, H. F. Moore

For several years there has been in progress in the Materials Testing Laboratory of the University of Illinois an investigation of creep and fracture of lead and lead alloys. In the course of this investigation it has been shown that the phenomenon of creep occurs in part at the grain boundaries of lead and lead alloys. To study the occurrence of creep and the development of fracture within crystalline grains, two series of tests of single crystals of lead have been carried out. The first of these, a preliminary series, by Mr. Betty, has been described.l,2 The second, pursued by Mr. Baker for his doctoral dissertation, was carried out under the direction of Professor Moore, with the assistance of Prof. G. L. Clark in the X-ray work, and the cooperation and advice of Mr. Betty. This paper is based on the test data obtained in this second series. Single crystals of a very pure commercial lead have been prepared, some of them tested to measure creep, others tested to fracture under long-continued steady load, and still others tested under cycles of repeated tension. An interpretation of the test data of these single-crystal tests is offered, which is a combination of parts of several well-known theories. Specimens The single-crystal specimens were made from a piece of very pure commercial lead sheathing. A spectroscopic analysis of one of the single crystals showed the presence of 0.005 per cent Bi, 0.0001 per cent Cu and 0.0003 per cent Ag. Preparation.—The Bridgman method of casting single-crystal specimens was used.3 The specimens were cast to the shape and size shown in Fig. 1 (dimensions in Fig. 4c) in a duralumin mold. Molten lead does not stick to duralumin. Fig. 1 shows the mold and the blast flames for heating. After the mold had been heated to the temperature of molten

Jan 1, 1938

By John B. Baker, Bernard B. Betty, H. F. Moore

For several years there has been in progress in the Materials Testing Laboratory of the University of Illinois an investigation of creep and fracture of lead and lead alloys. In the course of this investigation it has been shown that the phenomenon of creep occurs in part at the grain boundaries of lead and lead alloys. To study the occurrence of creep and the development of fracture within crystalline grains, two series of tests of single crystals of lead have been carried out. The first of these, a preliminary series, by Mr. Betty, has been described.l,2 The second, pursued by Mr. Baker for his doctoral dissertation, was carried out under the direction of Professor Moore, with the assistance of Prof. G. L. Clark in the X-ray work, and the cooperation and advice of Mr. Betty. This paper is based on the test data obtained in this second series. Single crystals of a very pure commercial lead have been prepared, some of them tested to measure creep, others tested to fracture under long-continued steady load, and still others tested under cycles of repeated tension. An interpretation of the test data of these single-crystal tests is offered, which is a combination of parts of several well-known theories. Specimens The single-crystal specimens were made from a piece of very pure commercial lead sheathing. A spectroscopic analysis of one of the single crystals showed the presence of 0.005 per cent Bi, 0.0001 per cent Cu and 0.0003 per cent Ag. Preparation.—The Bridgman method of casting single-crystal specimens was used.3 The specimens were cast to the shape and size shown in Fig. 1 (dimensions in Fig. 4c) in a duralumin mold. Molten lead does not stick to duralumin. Fig. 1 shows the mold and the blast flames for heating. After the mold had been heated to the temperature of molten

Jan 1, 1938

By A. C. Losekamp, R. M. Fincel, J. B. Conway

TANTALUM like several other metals exhibits a great affinity for or reactivity with certain gases. Tested in atmospheres which are not completely pure this metal becomes contaminated by certain impurities (notably nitrogen, oxygen, and hydrogen) with a resultant change in various properties. Well-known are the drastic changes in hardness, ductility, and electrical resistivity. Also previously recorded are the distortions of the lattice1,2 accompanying the increased content of oxygen and nitrogen in tantalum. This pronounced affinity for certain gases along with the significant property variations thereby produced makes it necessary to observe additional experimental precautions in making various property determinations with tantalum. Some recent measurements of the linear thermal-expansion characteristics of tantalum have made this point quite emphatically. Failure to observe the greatest precautions in reducing the contaminating influence has led to some extremely distorted results. Not only does such operation lead to different heating and cooling curves during the thermal-expansion measurements, but upon cooling to room temperature the sample is found to have suffered a permanent (actually semipermanent since the specimen can be returned to its original length by a 3-hr degassing treatment in vacuum at 2300°C) elongation. In addition, subsequent heatings will not follow the initial heating curve unless the expansion measurements are based on the actual specimen length at the beginning of the heating cycle. These thermal-expansion measurements were made by positioning the specimen horizontally at the longitudinal midpoint of a 20-in.-long, 4-in.-diam resistively heated tungsten tube furnace. The specimens were in the form of 20-mil sheet formed into a sharp U-shape about 0.3 in. in width and 0.3 in. in depth. Fiducial marks in the form of 0.010-in. holes drilled at either end of the 2.5-in.-long sheet specimens were viewed by a paired filar micrometer telescope system mounted on an Invar bar on the top of the furnace. Tests were made in helium with temperatures measured by a Pt/Pt-lORh thermocouple to 1000°C; above 1000°C temperature was measured by means of an optical pyrometer sighted into a black-body hole drilled into the specimen-holding fixture in the vicinity of the specimen. Previous tests with black-body holes drilled in a 0.25-in.-diam rod specimen had confirmed the temperature uniformity between specimens and specimen-holding fixture in this furnace. A typical thermal-expansion curve for arc-cast tantalum in helium is shown in Fig. 1 for the case where no attempt is made to remove all the impurities from the cover-gas atmosphere. The initial heating curve appears smooth and has a shape characteristic of all metals. However, it is known that the sample begins absorbing impurities at temperatures above 1000°C which are sufficient to distort the lattice and lead to specimen lengths which are somewhat larger than would be obtained in the absence of contamination. During the cooling cycle the expansion curve is seen to be significantly different from the heating curve. This is due to the impurity content causing a semipermanent (i.e., permanent until the impurities are removed by vacuum degassing) deformation which will not allow the speci-

Jan 1, 1965

By H. Papazian, Robert A. Lad

SINCE it can be shown both theoretically'' : and experimentally that disordered Cu3Au has a greater internal energy than the ordered alloy, it might be expected that its chemical reactivity would be greater. Experiments were initiated' to test this hypothesis. This note will describe some recent results obtained in the study of the rates of corrosion of ordered and disordered polycrystalline Cu3Au by aqueous FeCl., The work of Robertson' has indicated that the attack by such solutions is intergran-ular and highly orientation dependent. It was of interest to see whether the order-disorder effect was great enough to overcome the variations from specimen to specimen which would arise from this type of attack. The polycrystalline alloy specimens (0.020 in. wire, 1¾ in. long) were preannealed in ½ atm H, at 700°C for 2 hr. The subsequent heat treatments to produce order and disorder were performed in M atm He. Disordered specimens were obtained by heating at 450°C for 2 hr and quenching in water. Ordered specimens were produced by heating for 2 hr at 450°, furnace cooling to 380°, and soaking at 380°C for 80 to 90 hr. Room temperature was reached by cooling to 150" at a rate never exceeding 7" per hr, and water quenching from 150°C. The specimens so produced exhibited electrical resistivities characteristic of the two states; of the order of 11.27x10 ohm-cm for the disordered, and 4.28x10 ohm-cm for the ordered specimens. The corrosion rates were studied at 30°C in ferric chloride solutions of several concentrations (?,¼, 1.5, and 1 molar). The specimens were attached to a stirrer during the tests. Tests were interrupted at intervals, and the specimen weight change was determined after washing and drying. Analysis of the solutions showed that the attack was limited to the copper. The higher corrosion rate for the disordered alloy, as illustrated in Fig. l, is typical of the results obtained. The effect of variation in ferric chloride concentrations is indicated in Table I for typical specimens. The variations in the ratio of reactivity for disordered and ordered specimens at the different concentrations are within experimental error, and the best value is estimated to be near 1.4. The experimental variation was due in part to the mode of attack, as mentioned, and in part to the fact that films were formed on the specimens under some conditions. Electron diffraction patterns of the films were very complex and indicated the presence of metallic iron, as did chemical analysis. In an attempt to eliminate the difficulties arising from the mechanism of attack, single crystal specimens were used. A greater reaction rate was again measured for the disordered specimens, but the reproduci-bility was no better than that for the polycrystalline metal. This would indicate that film formation was primarily responsible. It was concluded that the reaction with aqueous ferric chloride served to demonstrate that the reactivity of disordered Cu3Au is greater than that of the ordered alloy. However, the difficulties with film formation did not permit determinations of a precision great enough to warrant extension of the study to partially ordered alloy systems.

Jan 1, 1957

By Leo J. Vogel, E. D. Hummer, David J. Akers

INTRODUCTION An efficient refuse-disposal system is a necessary part of the modem cleaning plant. The large-scale refuse system and disposal area, engineered for the lifetime of the plant, has become more important due to the greater tonnages of refuse produced from increased quantities of mechanically mined and prepared coal. Laws and increased government regulations have affected the design and operation of disposal systems. THE EFFECT OF MINE AND PLANT OPERATION Refuse disposal starts at the mining face. The mining system, the type of roof support, the machinery used, and the degree of discipline at the face contribute to the amount and type of refuse that must be removed through the disposal system. Economies gained through modification of the mining system or mining machinery may be partially offset by increased dilution of the mined coal with impurities from associated rock formations. In some cases the change in the mining system and equipment has reduced the dilution. In all cases the ratio of impurities that must be removed from the raw-coal feed to the plant not only affects the maintenance and

Jan 1, 1979

By C. A. Bruch, J. F. Duffey

On the basis of metallographic and cooling-rate studies of 15 U-Zr alloys, a new version of the 6 phase region of the U-Zr phase diagram is proposed. IN several published diagrams of U-Zr alloy system:' there is good agreement that at elevated temperatures complete solid solubility exists between y uranium and ß zirconium. Similarly, there is reasonably good agreement concerning the uranium-rich and zirconium-rich ends of the diagram. However, there is no agreement concerning the nature of the diagram at intermediate compositions and at temperatures below about 650°C. The early work of Saller et al.8 hows an intermediate phase, 6. In a later diagram by Saller and Rough' shown in Fig. 1, the d phase field is drawn with dotted lines, indicating doubt that this phase exists. The diagram of Summers-Smith2 does not show the d phase. More recently Holden and Seymour' have shown that in the composition range 40 to 60 wt pet Zr, the high-temperature ? phase, which is body-cen-tered-cubic, transforms to an ordered structure, 8. They found that the order-disorder transformation occurs between 595° and 610°C, and presented a diagram based on the study of four different alloy compositions. Most recently Saller et a1.5 presented a new diagram which differs with respect to the composition limits of the 8 field from the others proposed by these authors. The purpose of the present investigation was to determine the boundaries of the d phase field. Experimental Procedures and Results Alloys—Buttons, weighing 80 g of 15 different alloy compositions were prepared by arc melting Mal-linckrodt uranium and iodide-process zirconium in a water-cooled crucible. A controlled atmosphere of argon and helium was maintained in the furnace. Prior to making each button, a sacrificial button of zirconium was melted to increase the purity of the furnace atmosphere. Each alloy was then melted six times to improve its homogeneity. Subsequently the alloy buttons were jacketed in copper and hot rolled to slabs at 775°C. From these slabs, specimens were machined for chemical, thermal, and metallographic analyses, Table I gives both the estimated chemical composition of the alloys, and the values which were obtained by analysis. The oxygen contents varied from 0.013 to 0.032 pet, nitrogen from 0.0014 to 0.014 pet, and carbon from 0.0013 to 0.011 pet. The purity of the alloys ranged from 99.947 to 99.975 pet. Thermal Analysis—The specimens for thermal analysis were blocks 11/4 x 1/4 x % in. The bead of a calibrated thermocouple was placed between two of these blocks and molybdenum wire was wrapped around the assembly. Each assembly was sealed in a quartz capsule having an argon atmosphere. The capsule was placed inside a refractory crucible which was heated in a furnace. Using a method described by Smith,' the emf of a differential thermocouple, with junctions inside and outside of the refractory crucible, was used to activate the

Jan 1, 1959

By M. H. Loveman

The orebody described below has been rediscovered and developed within the last 3 years. It has, however, been known and worked by the Chinese for hundreds of years. When assay values and size are considered, it contains what is probably one of the largest single bodies of zinc and lead sulphides yet found. The tonnages developed at other places, as at Broken Hill, are much greater but the average zinc and lead sulphide contents are considerably lower than at Bawdwin. Bawdwin is situated in the semi-independent State of Tawng Peng, one of the numerous units which make up the Northern Shan States. These States are under British rule and are generally considered as a portion of Burma. They are governed as a separate administrative unit, however, under the Lieutenant Governor of Burma. Each State is under its own chief, or Sawbwa, who has considerable power over his own subjects. Bawdwin is approximately in latitude N 23°6', longitude E 97°201, about 50 miles south of the nearest point on the Chinese border and 450 miles north of Rangoon (Fig. 1). The period at which mining was first begun at Bawdwin is unknown. The most reliable records have been obtained by deciphering local Chinese inscriptions and from these it is concluded that the work dates back to at least the beginning of the 15th century. The first undoubted reference to the mines by a European is by Syrnes in 1795. Crawford in 1827 estimated the output of silver from the mines at $600,000 anually. At about the middle of the 19th century the rebellion of the Chinese Mohammedans in the neighboring Chinese province of Yunnan so weakened the power of the Chinese that the incursions of hostile tribes (Kachins) made work extremely dangerous. The mines were finally abandoned by the Chinese about 1868. The . closing down of the mines was probably not entirely due to outside causes but may have been influenced somewhat by the increasing difficulty of handling the water, as the workings gradually descended below the water level of the district. Several attempts were made by the Burmese kings, Mindon Min and Thebaw, to resume operations, but because of a

Jan 1, 1917

By C. F. Wang

Manchuria in General Manchuria, called the "Three Eastern Provinces" in Chinese, forms the northeastern corner of China and is bordered by Siberia on the north and northeast, and by Korea on the east. It is a land famous in Chinese annals as the place of origin of the Ching dynasty, and in more recent times it has been an arena for diplomatic maneuvering and commercial competition between the Russians, advancing from the north, and the' Japanese from the southeast. It derives its name of "three eastern provinces" from the fact that it is divided into three provinces; Hei-

Jan 2, 1918

By Robert Henderson

Several very interesting articles have been written on the caving system of mining, but most of these papers have dealt separately with the slusher system or the chute and grizzly system. In this paper, a comparison will be made of the two methods, both of which are being used at the Climax mine. The mine is on the Continental Divide, in central Colorado, at an altitude of approximately 11,500 ft. above sea level. The long, cold winters, characteristic of the high Rockies, create a number of operating problems not usually found in other mining areas. The Ore Body The Climax ore body is just east of the Mosquito fault. This structural deformation has brought the granite on the east against the sedimentary rocks on the west. The ore occurs in an intensely altered granite and schist around a silicified granite core. The ore is in a highly fractured zone of moderate silicification. The principal mineral, molybdenite, is found in these fractures. Barren dikes of granite porphyry cut through the ore body and core with no apparent regularity. The grade of the ore is fairly uniform and gradually decreases toward the footwall core and also into the hanging-wall granite. The footwall and hanging wall are determined entirely by assays. The ore body is roughly dome-shaped, with the apex truncated at the surface. It is covered to varying depths with talus. A horizontal section of the ore body on the Phillipson level appears as an annular ellipse surrounding the footwall core. The ring of ore varies in width from 300 ft. to as much as 800 ft. The north-south axis of the core is about 1200 ft. and the east-west axis is about 1800 ft. In the ore zone, the rock is sufficiently strong to maintain reasonably large openings, and openings larger than haulage drifts usually have to be supported. The ore is cut by a great many fractures and shears and breaks into rather large blocks when caved, necessitating considerable secondary blasting. The waste that overlies the ore body breaks relatively fine in comparison with the size of the blocks of the caved ore and tends to run through the broken ore in the cave, causing dilution unless the draw is carefully controlled. Mining Systems For several years the ore was mined by the chute and grizzly system, a system that differs from that used in other caving mines only in the size of openings and equipment. In the chute and grizzly system, main haulage laterals were driven along the footwall core and also along the hanging wall. Between these laterals, at

Jan 1, 1946

Abrahamson. Guy C., (S'43) Univ. of California, Berkeley. Calif. ' Abrego, Alfredo, (S'43) Texas College of Mines Metallurgy, El Paso, Texas. Adamec, Lew, (S'42) c/o Braden Copper Co., Ran¬cagua, Chile. Adams, Charles E., (S'42) Box 1527, Stockton, Calif. Adams, John W? (S'42) Asst. Petr. Engr., Vander¬ bilt Dist., Magnolia Pets. Co., Edna. Texas. Adams, Karl S., (S'43) Univ. of New Ha mpshire, Durham; N. H. Adamson, Charles R., (S'41) Univ. of Utah, Salt Lake City, Utah. Aguilar, Ruperto G., (S'43) Texas College of Mines, El Paso,. Texas. Almone, Francis M., (S'41) Univ. of Toronto, Toronto, Ont., Canada. Ainge, Ronald Farra, (S'43) Otago University, Dunedin, New Zealand. Akarun, Cevdet A., (S'44) Pennsylvania State College, State College. Pa.

Jan 1, 1944

By E. A. Anderson, C. W. Siller, Gerald Edmunds

In the pressurc die-casting of zinc alloys it is customary to force the molten alloy under high pressure into a permanent steel die by means of a plunger moving in a bushing that has a clearance on the diameter of the order of 0.002 in. Successful operation of the plunger type of machine requires the presence in the zinc alloy of certain percentages of aluminum. Without these aluminum additions, the normal reaction of molten zinc on ferrous materials causes sticking of the plunger arid a complcte shutdown of the equipment. All of the zinc alloys used for pressure dir-rnsting today contain approximately 4 per cent of aLUminum, which is more than suffieient to make plunger opcration feasible. The clearancc bet,ween the plunger and its bushing is an important matter. As the space bccomes larger, there is a loss in effective metal pressure. Ordinary gray cast iron served fairly well and is still uscd in some machines. However, the rate at which the plunger c1earance. increases with this material is considered by many to be far too great. There is, therefore, a serious interest in finding new matcrinls more: capable of retaining the desired clearance during long periods of use. Today marly die casters are using special materials for plungers and bushings selected by the somewhat expensive and time-consuming test of actual experience. An analysis of the problem reveals two possible end points of plunger. operation: (1) the building up of zinc-alloy plunger-material reaction products in sufficient bulk to cause sticking and (2) rapid solution, wear or erosion, all of which will increase the clearance to an undesirable extent. If neither of these takes place, the pluriger will operatc for a long time, of course.. The authors have developed a laboratory apparat,us in which the action of a plunger moving in a bushing immersed in molten zinc alloy could be simulated closely. Such a machine made possible a more rapid and less expensive survey of the available construction materials and an analysis of the specific alloying reactions taking place in the clearance area.

Jan 1, 1940

By Gerald Edmunds, C. W. Siller, E. A. Anderson

In the pressurc die-casting of zinc alloys it is customary to force the molten alloy under high pressure into a permanent steel die by means of a plunger moving in a bushing that has a clearance on the diameter of the order of 0.002 in. Successful operation of the plunger type of machine requires the presence in the zinc alloy of certain percentages of aluminum. Without these aluminum additions, the normal reaction of molten zinc on ferrous materials causes sticking of the plunger arid a complcte shutdown of the equipment. All of the zinc alloys used for pressure dir-rnsting today contain approximately 4 per cent of aLUminum, which is more than suffieient to make plunger opcration feasible. The clearancc bet,ween the plunger and its bushing is an important matter. As the space bccomes larger, there is a loss in effective metal pressure. Ordinary gray cast iron served fairly well and is still uscd in some machines. However, the rate at which the plunger c1earance. increases with this material is considered by many to be far too great. There is, therefore, a serious interest in finding new matcrinls more: capable of retaining the desired clearance during long periods of use. Today marly die casters are using special materials for plungers and bushings selected by the somewhat expensive and time-consuming test of actual experience. An analysis of the problem reveals two possible end points of plunger. operation: (1) the building up of zinc-alloy plunger-material reaction products in sufficient bulk to cause sticking and (2) rapid solution, wear or erosion, all of which will increase the clearance to an undesirable extent. If neither of these takes place, the pluriger will operatc for a long time, of course.. The authors have developed a laboratory apparat,us in which the action of a plunger moving in a bushing immersed in molten zinc alloy could be simulated closely. Such a machine made possible a more rapid and less expensive survey of the available construction materials and an analysis of the specific alloying reactions taking place in the clearance area.

Jan 1, 1940

By Jed H. Mosgrove

One of the most interesting of all the subjects required of persons studying the different facets of coal mining is coal mine gases. Some mine gases have been a real problem since the very beginning of underground mining, and in the early days there was insufficient knowledge to cope with them. The history of mining shows that until about the last 50 years, much work was done primarily by the hand methods which are primitive by today's standards. Miners had to contend with gases without the aid of enclosed lighting, permissible mine machinery, sophisticated testing devices, and high-pressure ventilating fans. In early days the miners were not educated about the different mine gases nor did they have the technical equipment to determine the actual composition of the deadly atmospheres they encountered. They simply applied a descriptive term to each gas or mixture of gases depending on its, effect on a person or the surrounding atmosphere. The gases or mixtures of gases were then referred to as "damps," a term which was probably derived from the German word "damps," meaning vapors or gases. The more common damps encountered were : Blackdamp A condition of the atmosphere in which a miner's light would be extinguished and in which breathing would be difficult, sometimes even resulting in suffocation. An atmosphere deficient in oxygen which could contain a combination of any of the mine gases. Firedamp A flammable mixture of methane and air which would either burn or explode when ignited. White Damp A mixture of gases containing carbon monoxide, most often found in mines during fires or after explosions.

Jan 1, 1981

By A. L. Hay

The Sydney coal field, the largest and most valuable in Nova Scotia, is situated on the northeastern coast of the Island of Cape Breton, extending from Mira Bay on the south to Cape Dauphin on the north, a distance of 30 miles, and has a general dip northeast under the sea. (Fig. 1. The field embraces the mining villages of Morien, Birchgrove and Reserve and the towns of Dominion, Glace Bay, Waterford and Sydney Mines. The city of Sydney is situated about midway between the northern and southern extremities of the field and on the western fringe of the productive coal measures. Sydney harbor crosses the coal field, cutting off direct rail connection between Sydney Mines and the greater part of the field to the southeast. (Fig. 2.) The coal measures are exposed in the cliffs on the coast line, which rise to an average height of 30 ft., and are almost continuous throughout the length of the field. The portion of the coal field under land forms a small segment of a circle, the greatest distance from the coast landwards is 9 miles, and it occupies an area of 200 sq. miles. The greatest distance developed seawards from the shore by mining operations is 2 miles. The strata maintain a regularity of dip at this distance, proving a submarine area of about 70 sq, miles. How much further the coal field extends seawards is unknown, but the indications are that it extends far beyond the present economical working limit and in all probability there is a vast submarine coal field. The productive coal measures are of Carboniferous age, these being underlain by beds of sandstone, locally classed as millstone grit, which define the southern limit of the field, while a spur of syenitic hills cuts off the coal-bearing strata on the north. Two main anticlinal folds having a general course easterly divide the field into three basins named from north to south: Sydney Mines-Lingan, Glace Bay and Morien. So far as the portion of the coal field already developed is concerned the general effect of these folds is to vary the direction and dip of the strata at different points of the several basins. The strata dip seawards at the average rate of 6 per cent. along the axes of the basins. On both sides of the several basins, the strata have a dip varying from 7 to 40

Jan 1, 1930

By H. W. Young

DEVELOPMENT of high-tension outdoor substations during the past few years has been due primarily to economic reasons. The demand for power in small communities could not be met with the conventional and 1 FIG. 1.-33,000-VOLT STEP-UP OUTDOOR AIR-BREAK SWITCH AND SUBSTATION INSTALLATION OUTSIDE OF A POWERHOUSE GENERATING AT 2300 VOLTS STEPPING UP TO 33,000. TWENTY-ONE COAL MINES ARE SUPPLIED FROM LINES LEADING FROM THIS INSTALLATION. comparatively expensive indoor types unless the rate for service was materially increased. That the various problems incident to development have been solved successfully, it is only necessary to point to the

Jan 9, 1919