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NEW MEMBERS The following list comprises the names of those persons who became members during the period Aug. 10 to Sept. 10, 1914: Members ALLEY, HARRY MCCAMMON, Mill Foreman .... Churchill Mining Co., Wonder,2 Nev. AMBLER, J. OWEN, Met..; ... Calumet and Arizona Mining Co., Douglas, Ariz. ANDERSON, JAMES WILLOUGHBY, Duell, Warfield and Duell, 2 Rector St., New York, N. Y. ANTISELL, FRANK L., Asst. Supt Raritan Copper Works, Perth Amboy, N. J. CARRINGTON, FRANK GAMBLE, Sec'y and Asst. Mgr., Standard Foundry Co., Anniston, Ala. CONKEY, CHARLES ROLLAND, Structural Draftsman, Barnett McQueen Co., Ft. William, Ont., Canada. COOK, PAUL RICHARDSON, Mill Shift Boss, Buckhorn Mill and Cyanide Plant, Buckhorn. Nev.

Jan 10, 1914

By M. H. Shumate

Rope-type haulage has had many applications in the mining and allied industries. Records have indicated favorable results both from a standpoint of efficiency and investment. The Truax-Traer Coal Co. has used some variations of rope haulage at their mines and preparation plants. They have built a system which solves their particular problems, and have an investment which has indicated an annual savings in operating costs. Rope haulage, as applied to the mining industry, goes back many years for both underground and surface mining, or a combination of both. The Truax-Traer Coal Co. has used gravity retarding hoists as well as several variations of rope haulage, including electrical and combinations of both, but each was limited in its use and application by natural conditions and economies of the operation. Several systems of rope haulage equipment are offered by manufacturers today for handling railroad car movement on a limited or continuous basis. The portal and railroad loading facilities of Truax-Traer Coal Co.'s Burning Star Slope mine, located in Jackson County, Ill., were moved in 1960. The old location was abondoned, eliminating 3% miles of underground track haulage. The mine was converted to an all-belt system, and coal is loaded at a new raw coal plant and shipped by railroad cars to a central cleaning plant. The company wanted to operate the surface facilities as efficiently as possible, employing a minimum number of workers, using the latest type railroad car movers. The existing rope haulage facilities at several locations throughout the country were examined and considered for the Slope mine location. The application of each appeared favorable but lacked flexibility, and it was difficult to justify the capital investment. The company decided to investigate the possibility of building a system that would apply to their problem, and have an investment that could be amortized in a relatively short period. SPECIFICATIONS They employed the services of Allen and Garcia Co. of Chicago, Ill. Through combined efforts, a railroad car rope system was designed to specifications as shown in Fig. 1. The Falk Corp. of Milwaukee, Wis. built the hoist to the specifications as shown in Fig. 2. It has an all welded base and pedestals. The all welded drum is not grooved. A single helical gear was used in lieu of herring bone type. A Falk speed reducer, Unit 90Y3-A, is driven by a 25-hp 1800-rpm, 440-V ac type 'C' (high starting torque) drip-proof, Frame 324-U motor. The speed reducer shaft is equipped with a solenoid operated ac spring set shoe brake, operating on a 7-in. diam. brake wheel. The dolly car, shown in Fig. 3, was field constructed, using the trucks and frame of a railroad tank car. Truax-Traer did not alter the frame but added plates and anchors for hoist ropes and frames for 8.5 tons of concrete to be used as ballast on the car. The limit switch operating shoe was also installed and the car coupler latch mechanism overhauled. The hoist rope selected was 1% in. in diam., 6x37 improved plow steel extra flexible, right lay, regular lay, with independent wire rope core, and preformed. Wedge sockets were used to connect rope to the dolly car as shown in Fig. 4. The system employs two 30-in. and three 16-in. diam. sheaves. All are bronze bushed and equipped with grease fittings. Larger sheaves are used for directional change of hoist rope and the smaller ones as snub sheaves to correct fleet angle of rope as it approaches the hoist drum. The Trench lay cable, buried between the two tracks, is used for electrical distribution and controls between hoists and operator's cab. Foundations for the system required 187 cu yards of reinforced concrete using approximately 60 cu yd each at three locations. Four hoists are employed in the system, two for each track. A pair is interconnected electrically and when one operates, moving the cars, the tail hoist idles with brake released. The process is repeated for the reverse direction. A limit switch, mounted in the track near each end of the system, is tripped by the dolly car as it approaches the hoist. The limit switch controls movement in one direction only, protecting the dolly car and establishing positive con-

Jan 1, 1962

By Carville E. Sparks, Rollin Farmin

TRIAL installations of rock bolts, of the slit-rod-and-wedge type, were under way at several units of Day Mines, Inc., when Korean hostilities interrupted the already slow deliveries of steel bars to the Coeur d'Alene district. Factory-made bolts had not yet been put on the local market, so the program was halted for lack of supplies. Interest was revived by a visitor's description of wooden roof bolts. These were said to have been used briefly with apparent success in a coal mine, until apprehension voiced by the U. S. Bureau of Mines caused the practice to be suspended. To make wooden bolts for trial in ground support, Day Mines acquired a second-hand doweling machine equipped with two cutting heads, one to turn out the desired round rods of 2-in. diam, the other to turn out 1-in. rods to be used as powder-tamping sticks. This machine was installed in the all-weather sawmill of the Hercules mine unit at Burke, Idaho, where fabrication of the wooden bolts commenced early in 1951. Most of the mining in the Coeur d'Alene district is along steeply dipping veins in shaly quartzite and argillite of Algonkian age. Ground support commonly is required in zones where the rocks have been sheared, brecciated, and hydrothermally altered. Pressure from the sidewalls is more troublesome than weight overhead, but both increase with the size of the mine opening. Caving may come from a progressive sloughing of irregular rock fragments or from an exfoliation and buckling of the layered wall rocks. The disintegration is thought to develop from an initial elastic expansion of the rock toward the newly-created mine opening, followed by the dilation of many tiny partings in the rock by absorption of water. As the partings widen, masses of rock develop weight and become free to fall. The function of rock bolts is to prevent or retard widening of partings in the rock supported. Wooden Bolts, Wedges and Headboards Bolt assembly used by Day Mines consists of a bolt 4 or 6 ft long, two wedges 16 in. long, and a headboard 30 in. long, Fig. 1. All four pieces are made of local red (Douglas) fir, either green or well-soaked in the mill pond before it enters the sawmill. Bolts are fabricated from cants, 2 1/4 in. sq, cut from relatively straight-grained timber with a minimum of knots and trimmed to 4- and 6-ft lengths. The bolt then is turned in the doweling machine from 21/4 in. sq to 2 in. diam round, except for a 4-in. length at one end which is left full square to provide the striking head and the shoulder that holds the headboard in position for wedging. The foot end of the bolt is slit with a thin saw for a length of about 16 in., thereby making a slot to receive the wedge against which the bolt is driven for anchorage at the bottom of the rock hole. A similar slit, 12 in. long, is made in the opposite (head) end of the bolt to receive the second wedge, which crowds the headboard against the ground at the collar of the rock hole and puts the bolt in tension. The second slot is aligned 90" from the plane of the first slot to avoid Longitudinal splitting and is notched out slightly to allow easier insertion of the collar wedge after the bolt has been driven to bottom. To prevent splitting the headboard by spreading action of the head wedge, this slot is oriented at 90" to the grain of the headboard when the pieces are assembled, Fig. 2. The wedges are similar to standard mine wedges, but more slender; they are cut 1 7/8 in. wide and 1 in. thick at the heel and taper out in 16 in. of length. The headboard, or bearing plate, is not necessary for some types of ground but generally is desirable because it helps the bolt to support an area of loose, friable rock and reduces the tendency for the rock at the collar of the hole to split away from the wedged head by distributing the pressure over a wider rock surface. The headboard may be a 24-to 30-in. length of 3-in. plank, 8 to 12 in. wide, but a similar length of rounded sawmill slab serves equally well at 20 pct of the cost. A hole of 2-in. diam is bored or punched through the center of the headboard, either at 90" or at various high angles to its surface. The bolt is inserted to its shoulder through this hole, then driven into the rock hole. Bolts, wedges, and headboards are given a full timber preservative treatment to inhibit rot. Bundles of each are immersed in a warm saturated solution of Osmose salts in water for 48 hr, removed, dripped dry, and stored in a relatively humid underground depot to cure. Most wooden rock bolts used by Day Mines are 4 ft long. Holes to receive them, about 42 in deep and 2 1/8 in. in diam, are drilled into the rock' to be supported, nearly normal to the periphery of the mine opening. The type of drill used is dictated by convenience: stoper, jackleg, or jumbo-mounted drifter. Correct depth of the hole is assured by use of a measuring stick that has been cut to the proper distance from drill chuck to the ground at the collar of the hole when a standard length drill rod is at the bottom. The bolt is seated to the shoulder through the hole in the headboard, the foot-end wedge is placed in its slot, and the assembly is inserted into the rock hole. Then the bolt is driven until it is seated solidly on the wedge against the bottom of the rock hole. Driving may be by hand with a sledge, or

Jan 1, 1954

By W. A. James

NATURE endowed the Niagara Frontier with great resources but it was the molding of these resources by the early pioneers that assured its future development. This great industrial district of New York stretches along about fifty miles of shore line on the eastern end of Lake Erie and the Niagara River, embracing the two counties of Erie and Niagara, with the city of Buffalo about in the center. This location at the junction of the eastern end of the Great Lakes and the western boundary of the State, a great focal point of land and water, transportation, guaranteed the development of the Frontier. Although the first white settlers came to this section in 1784, it was not until after the turn of the nineteenth century that real development started. Perhaps the most significant influence in the early days was the completion of the Erie Canal between Buffalo and Albany in 1825. This then monumental achievement gave Buffalo an advantage in the race for the best trade route to the Western

Jan 1, 1938

By Jun Hino, P. G. Shewmon, P. A. Beck

THE investigations of Crussard,' of Guinier and Tennevin,' and of Dunn and Daniels," indicate that the subgrains formed in a cold worked and annealed metal are capable of growing at each other's expense during annealing, if the temperature of annealing is sufficiently high and the time is long enough. The results of Dunn and Daniels are particularly convincing in showing that subgrain growth is essentially the result of the free surface energy associated with the subboundaries. In subgrain growth, as in ordinary grain growth, energy is gained as a result of the decrease in total subboundary surface area per unit volume. Recently, Wood and Scrutton4 found that the rate of subgrain growth upon annealing increased very considerably, if simultaneously a creep strain was applied to the specimen at a low strain rate. Working with 99.98 pct pure fine-grained aluminum, these investigators found that the continuous X-ray diffraction back-reflection rings of material strained at room temperature remained continuous after heating for ten days at 250 °C. However, when heated at the same temperature under a stress of 1000 psi even for only three days, the formerly continuous X-ray diffraction rings broke up into numerous dots, which were fairly clearly separated from each other. The continuous X-ray diffraction rings were interpreted as indications of a very small subgrain size, not resolved by the X-ray diffraction method used. The breaking up of the continuous X-ray diffraction ring during annealing under stress was taken as an indication of a great increase in subgrain size, so that the individual subgrains could then be resolved. The effect of simultaneous strain at a low strain rate in accelerating subgrain growth, discovered by Wood and Scrutton and designated by them as "cell growth," is of fundamental importance. The experiments described in this note were carried out in order to confirm Wood and Scrutton's results by direct metallographic observation. Also, information was sought as to the minimum creep strain necessary to produce this effect. A fine grained high purity aluminum strip was prepared by alternate 33 pct rolling and annealing treatments for 1 hr at 350°C. Specimens cut from this strip were subjected to a relatively fast creep strain of 7.2 pct in 3.5 min at 300°C under a constant load initially corresponding to 1185 psi. The subgrains set up were large enough (about 0.015 to 0.03 mm) to be clearly observed (Fig. 1) at X200 magnification with polarized light, after electrolytic polishing and anodic etching, producing a fine oxide film." The corresponding X-ray diffraction pattern is shown in Fig. la. After the fast creep strain treatment a portion of the specimen was subjected to a creep strain of 8.3 pct in 44 hr at 350°C under a constant load initially corresponding to 320 psi. Another portion, annealed under the same conditions, but not strained, served as control specimen. The subgrain size of a typical area of the specimen annealed under strain and of the one annealed without strain is shown in Figs. 2 and 3 (X-ray diffraction patterns, Figs. 2a and 3a). Annealing without strain produced clearly observable subgrain growth (subgrain size: about 0.03 to 0.05 mm). The effect of simultaneous strain was to increase greatly the rate of subgrain growth (resulting in a subgrain size of approximately 0.05 to 0.13 mm), in accordance with Wood and Scrutton. In another experiment, the effect of the amount of simultaneous strain was studied. The initial subgrain structure was set up by fast creep, as described previously. The specimen was then heated at 350 °C under a constant load initially corresponding to 320 psi, as above, for 2.2 hr (0.24 pct strain), and 8.8 hr (0.58 pct strain). Comparison with the corresponding unstrained control specimens by means of X-ray diffraction showed that 0.58 pct strain definitely had an effect, but the effect of 0.24 pct strain was doubtful.

Jan 1, 1953

By James Norman

SPODUMENE is a lithium-bearing pyroxene, and is an important source of lithium compounds. Because of its high alumina and lithia content it might be a desirable constituent of glass batches. The use of spodu-mene in ceramics will undoubtedly increase, as it has been shown that a mixture of the proper proportions of this mineral with soda feldspar and potash feldspar has a much lower maturing temperature upon firing than has any one of the three components.1 The mineral spodumene seldom occurs as pure mineral, but ordinarily with feldspars, mica and quartz. All spodumene-bearing rocks tested contained these minerals as gangue. Small amounts of iron and manga-nese oxides also were present, usually as stains on the silicate grains. Mica associated with the spodumene carried a considerable amount of lithia. This was discovered in flotation tailings, which, although virtually free of spodumene grains when examined microscopically, showed 0.4 to 0.5 per cent Li20 on chemical analysis. The lithia content of micas picked from the North Carolina spodumene rock was variable. Some samples contained little lithia, others more than 3 per cent. In 1938, under the supervision of Oliver C. Ralston, ? the Bureau of Mines, in cooperation with the Tennessee Mineral Products Corporation, undertook to study the beneficiation of North Carolina spodumene by froth flotation. The Bureau had previously published investigations on the beneficiation of spodumene.2,3 The methods described in the second publication' did not give good results with badly weathered spodumene rock, so that more thorough investigation of the subject was warranted.

Jan 1, 1940

By C. McCulloch

OPEN-PIT mining of coal is relatively a recent innovation; men still active in the industry can trace its development. Re- viewing the growth of operations from the original horse-drawn scrapers, through the various stages of power equipment to the huge strip- ping shovels of today, one also notes changes in the methods of what the coal man calls preparation at the face. We really should not call it face preparation because, in contrast to underground mining, a face does not exist in strip mining. Further, preparation of the coal for market at the loading point has already, in but a few years, become largely of historic interest only and modern mines as well as old mines recently modernized rely almost entirely on separate and elaborate preparation plants to produce marketable coal. This practice was not voluntarily adopted by the producer but was forced upon him by the inadequacy of previous

Jan 1, 1939

By J. S. Crump, H. L. Stone

Laboratory studies have indicated that displacement of oil from a reservoir by means of a condensing gas drive results in extremely high oil recovery, approaching 100 per cent under the most favorable circumstances. A condensing gas drive is defined as a gas drive in which the gas utilized is appreciably soluble in the oil it is displacing. The laboratory studies consisted of a number of gas drive displacement experiments, all using a horizontal, sand-packed, steel tube as the laboratory reservoir. The experimental results indicate that the more soluble a gas is in the oil to he displaced, the more efficient that gar is as a displacing fluid. Experiments were conducted utilizing both a light, volatile crude and a heavy, asphalt crude as the in-place oil. In both cases, oil recovery was appreciably enhanced by solubility of the displacing gas. It is believed that the use of condensing gas drives would result in increased oil recovery from many reservoirs during either primary or secondary phases of production. INTRODUCTION Since the early days of the oil industry there has been an increasing awareness of the problems of oil recovery. During the last few decades particularly a growing recognition of the problems has led to widespread attempts on the part of the industry to increase oil recovery by improved technology. One method which has been used to increase recovery is the maintenance of reservoir pressure by injection of gas. Part of the beneficial effect resulting from this gas injection was to prevent evolution of the gas dissolved in the reservoir oil, since such evolution would cause the oil to shrink and become more viscous, thereby adversely affecting oil recovery. In most instances, the gas injected was predomillantly methane, and so the possibility of oil recovery by retrograde vaporization existed. Laboratory investigations of displacement of reservoir oils by methane, carried out at high pressure, have indicated that considerable additional recovery of light oils could be effected by vaporization, but only at the cost of a severe volumetric shrinkage of the residual oil which would cause a decrease in relative permeability to oil in the reservoir. Consequently, recovery of oil by physical displacement would be impaired. The study suggested, therefore, that recovery of oil might be enhanced by injecting into the reservoir a gas known to be appreciably soluble in the oil at reservoir conditions. Swelling of the oil due to solution of gas should result and yield a consequent increase in the relative permeability to oil. The work described in the following sections was, therefore, undertaken to investigate the possibility of increased recovery by this mechanism. Research similar to that reported in this paper has been conducted by The Atlantic Refining Co.1,2,3 In these studies, Whorton, et al, and Slobod, et al, used methane-rich gas to displace oil from model reservoirs. Solubility of the gas was achieved by keeping the reservoir pressure greater than the saturation pressure of the original oil, and the degree of this solubility was varied by operating at different reservoir pressures. Thus the Atlantic project was primarily a study of the effect of reservoir pressure upon oil recovery by gas drive. The objective of the work reported in this paper was to study the effect of gas composition upon oil recovery while holding the reservoir pressure constant. DESCRIPTION OF EXPERIMENTS The discussion of the preceding section suggests that

Jan 1, 1957

By Graham Bright

T HE chairman of the Mines Committee of the A. 1: E. E. for 1920-21 has had the honor of being also the chairman of a similar committee, the Mine Equipment Committee, of the A. I. M. E. It has been the endeavor during the past year to have the two committees work together since the object of these committees is very much the same. A meeting of the committees was held in Chicago in November of 1920, at which time it was decided that one of the best ways to work together would be to foster joint meetings of the local sections of the A. I. E. E. and A. I. M. E. By these meetings, it was hoped that various engineers in the local sections interested in mining subjects could be brought together and not only become better acquainted but be greatly benefited by the interchange of ideas and by the discussion of papers presented on mining subjects.

Jan 1, 1921

By R. W. Smith, C. Schroeder, R. Haddenham

Amphoteric surfactants are heteropolar organic compounds which possess at least two functional (ionic) oppositely charged groups per molecule. The ones studied are manufactured by General Mills and possess one or more long hydrocarbon chains plus a carboxyl group (s) and an amino or imino group. Hallimond tube and M. C. Fuerstenau micro flotation cell flotation tests were performed on quartz and hematite as a function of pH using amphoteric, cationic, and anionic surfactants as collectors. For the most part, flotation could be correlated with an interaction of charged groups on the collectors with oppositely charged sites on the minerals plus association of hydrocarbon chains. The comparison of flotation in a Hallimond tube and an M.C. Fuerstenau cell shows that one should use care in using the latter if one excludes an additional frother from the system. Also, it is interesting to note that sometimes greater collector concentrations are required in the Fuerstenau cell for comparable flotation recoveries.

Jan 1, 1974

By AIME AIME

THE initial meeting on Mining Methods* opened at 10 o'clock Monday morning with Scott Turner as chairman and W. Spencer Hutchinson as vice- chairman; about 60 attending. After preliminary announcements Theodore Marvin was called on for his paper,, entitled "Rock Tunnel Methods," which has been appearing serially in The Explosives Engineer. Marvin read the introduction and called attention to the account of one or' two particularly' interesting projects, such as the. Brooklyn water supply tunnel. E. D. 'Gardner, Char1e.s S. Hurter, L. D. Lamont and Spencer P. Howell took part in the discussion, Howell commenting on the fact that, in one case cited, misfires had occurred through detonator wires 'coming in contact with the case of an unapproved flashlight, .,: and that all flashlights should be approved.

Jan 1, 1931

By Bahngrell W. Brown

IN an age when anything short of miraculous can and does happen it is entirely too easy to become labeled as a prophet. After the first wave of hysteria over atomic weapons died down there were crystal gazers enough in that field. The mining fraternity, always anxious to get back to normal anyway, looked, was duly impressed, and passed on to more mundane affairs. After all it was just another big blast in the stopes of life. After we "laymen" had seen the effects at Hiroshima and been granted a peek into the phenomenon of Numbers 4 and 5, we saw, indeed, that it was a tremendous but understandable weapon. Now it appears that we may fall heir to much of the defensive planning of the future. If, as our military planners tell us, it will be necessary to go underground for defense, then we are the true forerunners of a race of troglodytes. The underground belongs to us as to no other profession; the subsurface is our prerogative. Already the big mistakes in planning atomic defense are being made. It is within our ability now to correct them. Surveys are being made of natural caverns to be used as a basis for military planning. This is our first big mistake. Even if the natural caverns, many of which Nature has precariously carved from cherty and brittle limestones, could withstand the seismic force of a proximate blast without major roof failures, there is a more serious argument against the blanket use of natural caverns as a first line of defense. In addi-

Jan 1, 1946

By William P. Blake

THE occurrence of enormous masses of pure copper has given the mining district of Lake Superior worldwide reputation. The first masses brought from there excited great attention, and directed the notice of the mining world to the few particular mines from which they were taken. It may not now be generally known that nearly all the veins which are worked, and which cut across the trap ridge, contain mass copper, and that large masses are continually being raised from them. The largest continuous mass which has been taken out was probably that from the Minnesota, in 1857, which is variously stated as weighing 420 tons and 470 tons. Its length was about 45 feet, its breadth or height 22 feet, and its greatest thickness 8 feet. All such masses are very irregular and ragged in their form and thickness, thinning out generally from a foot to a few inches, and straggling through the vein until they connect with other large masses. This was the character of a mass found in the Phoenix Mine, one of the oldest on the lake, which mass altogether weighed some 600 tons. But this was really a series of masses more or less connected by strings of metal, yet no one large part of it weighed, singly, over 200 tons. A similar series of masses, weighing about 600 tons, was extracted from the Minnesota. Some of the Phoenix masses were four to five feet thick of solid copper. The Cliff Mine has yielded masses weighing from 100 to 150 tons in one piece. One of 40 tons was taken out this year, besides numerous blocks weighing from 1 to 8 tons. This mine and the Central are now yielding mass copper in abundance. It is, of course, impossible to pick, or drill, or to break out such huge masses of solid metal when they are found, by drifting upon the course of the vein. The method of extraction is as follows The miner picks out or excavates a narrow passage or chamber upon one side of the mass, laying it bare as far as possible over its whole surface. It is usually firmly held by its close union with the vein-stuff, or by its irregular projections above, below, and at the end. If it cannot then be dislodged by levers, the excavation of a chamber is commenced behind the mass, and this excavation is made large enough to receive from 5 to 20 or more kegs of powder. In one

Jan 1, 1876

By William P. Blake

The occurrence of enormous masses of pure copper has given the mining district of Lake Superior worldwide reputation. The first masses brought from there excited great attention, and directed the notice of the mining world to the few particular mines from which they were taken. It may not now be generally known that nearly all the veins which are worked, and which cut across the trap ridge, contain mass copper, and that large masses are continually being raised from them. The largest continuous mass which has been taken out was probably that from the Minnesota, in 1857, which is variously stated as weighing 420 tons and 470 tons. Its length was about 45 feet, its breadth or height 22 feet, and its greatest thickness 8 feet. All such masses are very irregular and ragged in their form and thickness, thinning out generally from a foot to a few inches, and straggling through the vein until they connect with other large masses. This was the character of a mass found in the Phœnix Mine, one of the oldest on the lake, which mass altogether weighed some 600 tons. But this was really a series of masses more or less connected by strings of metal, yet no one large part of it weighed, singly, over 200 tons. A similar series of masses, weighing about 600 tons, was extracted from the Miunesota. Some of the Phœnix masses were four to five feet thick of solid copper. The Cliff Mine has yielded masses weighing from 100 to 150 tons in one piece. One of 40 tons was taken out this year, besides numerous blocks weighing from 1 to 8 tons. This mine and the Central are now yielding mass copper in abundance. It is, bf course, impossible to pick, or drill, or to break out such huge masses of solid metal when they are found, by drifting upon the course of the vein. The method of extraction is as follows: The miner picks out or excavates a narrow passage or chamber upon one side of the mass, laying it bare as far as possible over its whole surface. It is usually firmly held by its close union with the veinstuff, or by its irregular projections above, below, and at the end. If it cannot then be dislodged by levers, the excavation of a chamber is commenced behind the mass, and this excavation is made large enough to receive from 5 to 20 or more kegs of powder. In one

By H. C. Chang, N. J. Grant

Creep of very coarse grained high purity aluminum was studied at 400°, 700°, and 1100°F at initial stresses of 50 to 1200 psi. Local strain measurements were made across the grain boundaries and in different regions of various grains during creep, thereby permitting the drawing of component creep curves. The relative amounts of elongation as measured across a grain boundary and in the grains adjacent to the boundary depend on the temperature of testing. The significance of creep curve equations and activation energies is discussed. THIS paper presents some of the results of a research program devoted to the study of the mechanism of creep in high purity aluminum. Previous publications have dealt with the cyclic processes of alternating grain boundary sliding and migration, and the deformation in the grains caused by these processes;' the direction and the driving force of grain boundary sliding and migration;' the deformation in the grains and the restricting effects of the grain boundaries on this deformation." These previous papers were based mainly on either microscopic observations or X-ray data, or both. Sometimes creep curves across two closely spaced reference marks (about 0.6 to 0.7 mm apart) were also presented with a view to correlating the elongation values with the optical observations in general, and with certain deformation processes in particular. These curves shall henceforth be referred to as component creep curves. No attempts were made, however, to compare either the component creep curves which were obtained in different regions of a specimen, or those obtained from different specimens subjected to different creep test conditions. It is the purpose of this paper to present these component creep curves. Among the factors influencing the behaviors of these curves, those studied were stress, temperature, and grain arrangements in the specimens. It is proposed to show how greatly the deformation can vary from grain to grain and within an individual grain in a coarse grained specimen. The experimental technique and procedure have been presented.' It remains necessary to emphasize that the reference marks were produced by pressing a thin sewing needle into the surface of the specimen before the final annealing at 900°F for 24 hr and at 1150°F for 12 hr. The cold work around the needle indentations was therefore removed. The depth of these holes after electropolishing the annealed specimens was about 0.01 mm. This depth and area were negligible in comparison with the thickness of the specimens, 2.3 mm, and hence would not affect the creep behavior. Results Fig. 1 shows a development diagram of specimen P-8. The dots on the surface locate the needle point reference marks used to obtain the component creep curves. A curve obtained between two dots across a grain boundary measures not only the boundary deformation but also the deformation associated with boundary sliding occurring in the grains in the region between these indents. The original distance between two reference marks was about 0.6 to 0.7 mm. The maximum error of measurement was 0.01 mm, or in terms of percentage elongation, of the order of & 1.5 pct. Whereas the component creep curves shown in the figures to follow were drawn as a gross average of the points, in view of the fineness of some of the steps of grain boundary sliding and migration, as shown in the previous publications,¹,2 it appears logical to expect that some of the finer cycles of movement have not been delineated for the strain sensitivity of the measuring system. It seems justifiable to say that the curves are not as smooth as shown. 700°F Tests: Fig. 2 shows component creep curves across four of the grain boundaries in specimen P-8, tested at 700°F and 85 psi. These curves clearly show alternate cycles of increasing and decreasing

Jan 1, 1954

E. E. Russell Tratman, New York City (communication to the Secretary): Mr. Glenn's paper brings up again the question of the part played by coal-dust in colliery-explosions. In the discussion of Sir Frederick Abel's paper on " Accidents in Mines," read before the Institution of Civil Engineers,? much was said about the dangerous properties of coal-dust, and several instances were given of the successful use of a spray of water, water and compressed air, or exhaust-steam from an engine, to keep the mine SUEciently damp to prevent the formation of dust clouds. Methods of preventing shots from blowing out; of using water cartridges to prevent flame ; and of using lime cartridges, wedges and other means of breaking down the coal were also discussed. Mr. Emerson Bainbridge referred to the explosive termed " roburite " (ammonium nitrate and

Jan 1, 1895

By Carl Henrich

While the size of the blast-furnaces used for smelting leadand copper-ores has constantly increased, during late years, the manner of removing the slag from the furnace to the slag-dump has (until quite recently, at least) practically remained the same. The only appliance in practical use has been the two-wheeled slag-pot, holding about 300 to 400 pounds of slag, or as much as one man could manage to pull or push on a smooth, hard surface. When these slag-pots on wheels were first introduced, the daily capacity of a lead or copper blast-furnace hardly reached 30 tons of smelting-charge. With furnaces of this size, and even when the capacity had been doubled, this kind of slag-pot answered well enough. All the improvements made were in the construction of these pots and not in an increase of their size, which was limited by the weight which one man could handle. But the size of the furnace went on increasing. The daily consumption of one furnace rose gradually to 75 tons, 100 tons, and even more. The writer had occasion to construct some of these furnaces, which, in their day, were among the largest, if not the largest, of the water-jacketed kind then in existence. A water-jacketed furnace will always smelt more in the same time than a furnace with brick walls. Already, in those days, the slag-removal from these enlarged furnaces received due attention by the writer. The removal of 60 tons of slag in 24 hours, in pots holding only 300 pounds each, will require 400 pots to be filled in 24 hours; and when the amount.of slag increases to 90 tons, 600 pots will be required. That is to say, in the last case, 25 pots in each hour, or 1 pot each 24 minutes, will have to be put under the slagspout, filled, pulled away, and replaced with another. This will involve too much hurry for any degree of comfort, convenience

Jan 1, 1896

By Edward W. Parker, Marius R. Campbell

According to the estimates prepared by the U. S. Geological Survey, the area underlain by workable coal-beds in the United States is 496,776 sq. miles. Of this total area, 480 sq. miles contain the entire anthracite coal-fields of Pennsylvania. The bituminous coal-fields are estimated to be contained in areas, aggregating 250,051 sq. miles. The grade of coal between bituminous and lignite, and which is designated by the Geological Survey as " sub-bituminous," is estimated to be contained within areas aggregating 97,636 sq. miles, while the areas containing lignite aggregate 148,609 sq. miles. The coal-fields are divided, for the sake of convenience in classification, into six main provinces, as follows: 1. The Eastern. Province, containing the anthracite coal-fields of Pennsylvania and the bituminous coal-fields of the Appalachian region—namely, those of western Pennsylvania, Ohio, Virginia, West Virginia, Kentucky, Tennessee, Georgia, Ala bama, and small outlying areas in North Carolina. 2. The Interior Province, containing the bituminous coal-producing regions of Michigan, Illinois, Indiana, western Kentucky, Iowa, Kansas, Missouri, Oklahoma, Arkansas, and Texas. 3. The Gulf Province, containing the lignite-areas of Alabama, Mississippi, Louisiana, Arkansas, and Texas. 4. The Northern or Great Plains Province, containing the lignite and sub-bituminous areas of North and South Dakota, eastern Montana, and northeastern Wyoming. 5. The Rocky Mountain Province, containing the bituminous and sub-bituminous areas of western Montana and western Wyoming, Colorado, Utah, and New Mexico. 6. The Pacific Coast Province, containing the areas of Washington, Oregon, and California.

Jan 1, 1910

By W. T. Weller

In Part I, a study of pressure build-up curves calculated for conditions under which both oil and gas flow led to the conclusion that the presence of a dispersed free gas phase in an oil reservoir must be taken into consideration to estimate accurately average reservoir pressure and permeability from build-up curves. Familiar methods based on the assumption of no free gas can be extended to the two-phase case by using total compressibility and mobility in place of single-fluid compressibility and mobility. These methods give correct values for average pressure and permeability when gas saturation is small. Errors become larger as the gas saturation increases. However, for the use to which the results will be put, the methods are satisfactory for reservoir engineering purposes. An improved method of calculating the performance of depletion-type reservoirs is presented in Part 2. Because the mathematical relationships describing simultaneous flow of oil and gas are quite involved. simplifying assumptions are made to provide means of obtaining approximate solutions of reasonable accuracy. One such approximate method now in use is the constant-GOR solution. It involves the assumption that at any instant, the ratio of total gas flow rate (both free and disolved) to oil flow rate is the same at all points in the reservoir. The approach is not applicable unless the free gar saturation in the reservoir is everywhere greater than the critical gas saturation. This paper presents a modification which, by avoiding the constant-GOR assumption, makes the method applicable to all reservoir conditions, and so far appears to be more accurate than the constant-GOR solution and to he comparable in required compuctation time. PART I— BUILD-UP CURVE ANALYSIS INTRODUCTION Pressure build-up characteristics of shut-in wells have been used for many years by engineers to evaluate average reservoir pressure, effective permeability thickness of the pay section, effectiveness of well completion (skin effect) and reservoir size. A number of methods of analysis have appeared from time to time."" Without exception, these methods are based on the assumption that the reservoir contains but one fluid of constant small compressibility and constant mobility. It has been suggesteda" hat these single-fluid methods may be applied to data from reservoirs containing both oil and gas by substitution of some effective total properties of the multiphase system in place of the corresponding single-phase properties. The present investigation was undertaken primarily to evaluate this approach. METHOD A number of theoretical build-up curves were calculated for conditions of two-phase flow, under the assumption of certain reservoir and fluid properties, and were analyzed by single-fluid methods with appropriate total compressibility and total mobility values for the corresponding single-fluid properties. Results of the analyses were compared with the assumed conditions. The theoretical build-up curves were completed by procedures similar to those of West, Garvin and Sheldon." Since these calculations require a considerable amount of computer time, an attempt was made to derive an approximate calculation method. The attempt was unsuccessful for calculating build-up curves, but the effort did result in a new approximate method of calculating the performance of solution gas drive reservoirs, which appears to be an improvement over the constant-GOR method" used previously (see Part 2). The West, Garvin and Sheldon calculations involved the following assumptions: (1) the reservoir is circular and completely bounded, with a completely penetrating well at its center; (2) the porous medium is uniform and iso-tropic, with a constant water saturation at all points; (3) gravity effects can be neglected; (4) compressibility of rock and water can be neglected; (5) the composition and equilibrium are constant for oil and gas; (6) the same pressure exists in both the oil phase and the gas phase; and (7) no afterproduction occurs, i.e., the well is shut in at the sand face for build-up. These assumptions make it possible to describe two-phase flow of oil and gas by the partial differential equations:

Jan 1, 1967

By S. Stopek, E. D. Hinkley, R. H. Rediker

Epitaxial heterojunctions have been prepared by melting the lower -melting-point semiconductor of the interface between two dijferent semiconductors. when the temperature is reduced, the melted material recrystallizes, having alloyed into the higher -melting-point semiconditctor. The electrical and elcctro-optical properties of such single-crystal heterojunctions between GaAs and Gash and between p-type InAs and n-type Gash are the subject of this paper. The forward current varies as exp (AV), where A is substantially independent of temperatuve. For Gds-Gash heterojunctions at temperatures above, 370°K, if the current-voltage relationship were to he expressed as exp (qV/nkT), then n would he less than unity. The injection luminescence associated with forward current is, for the most part, characteristic. of the lower bandgap semicondutctor. These results can he explained by carrier injection into the lower bandgap semiconductor by tunneling through a barrier at the interface. The photovoltaic effect measured for incident photons having energies in the range between the bandgaps of the two semiconductors is much smaller than that produced by higher-energy photon The smallness of this between -the-gap photovoltaic response can he explained by the low probability for penetration of the barrier by the carriers produced in the smaller -bandgap semiconductor. THE technique of interface alloying has been used to produce single-crystal junctions between dissimilar semiconductors.' Oriented wafers are placed on a carbon heater strip, Fig. 1. so that semiconductor S1, which has the lower melting point, is supported by semiconductor S2. Electrical current passed through the heater strip produces a temperature gradient such that S2 is at a higher temperature than S1. As the temperature is raised the lower face of S1 begins to melt. Before the entire wafer can melt, however, the heater-strip current is turned off and, as illustrated in Fig. l. the melted portion recrystallizes, having alloyed into S2. Junctions have been fabricated by the above procedure between GaAs and germanium, between GaAs and GaSb, and between InAs and GaSb. Mroczkowski, Lavine. and Gatos have described the metallurgical and chemical aspects of the GaAs-Ge junction.2 The transition from GaAs to germanium is not monotonic and a portion of the recrystallized region consists of the GaAs-Ge eutectic. Since gallium is an acceptor and arsenic is a donor in germanium, since germanium dopes GaAs, and since the electrical properties of the GaAs-Ge eutectic have not been investigated, any interpretation of the electrical characteristics in terms of simple heterojunction theory would be incorrect. That the rectification of GaAs-Ge heterojunctions is not a property of the impurity doping of the GaAs or the germanium, but is most probably due to the impurity distribution in the recrystallized region, is clear from the fact that forward conduction occurred for all the GaAs-Ge interface-alloy junctions (whether they be n-n,n-p. p-n. or p-p) when the germanium was biased positively. The electrical characteristics of these GaAs-Ge heterojunctions will not be discussed further in this paper. Electron-beam microprobe analysis of GaAs-GaSb heterojunctions showed that the transition from arsenic to antimony atoms was without structure. and that the transition occurred within a 2 to 3 region.' In this paper we will describe the electrical properties of the GaAs-GaSb heterojunctions as well as electrical and electro-optical properties of the InAs-GaSb heterojunctions. A band model for the junction will be proposed which can explain these properties. ELECTRICAL PROPERTIES OF GaAs-GaSb HETEROJUNCTIONS After interface alloying. in preparation for the electrical and electro-optical experiments, ohmic contacts were made by conventional means. For example. Kovar tabs clad with tin were alloyed to n-GaAs or similar tabs clad with Au-Zn were alloyed to p-GaAs. The units were mounted and then etched. All four combinations of conductivity types

Jan 1, 1965