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By Juhani Pulkkinen, Pekka Lappalainen

Preplaced cable bolts - fully grouted old hoisting cables or stress relieved steel strands - have been used succesfully to pre- reinforce ore contact zones and pillars in sublevel stoping at Outo- kumpu Oy mines for ten years. The purpose is to make open stoping methods possible even in "poor'' conditions and to decrease waste rock dilution. Since 1971 more than 120 km cable bolting has been done, and plans for this year in five mines amount to 33 km. In order to understand the function of cable bolt, pull-out tests have been done both in the laboratory and in situ. Bond strength between cable and cement is highly dependent on cable structure and cable surface dirtiness. Steel cables with steel core and rough surface structure have highest bond strength ( 6 MP~). A cable bolt is a friction bolt. After losing its peak bond strength - after starting to move - a cable bolt still has a high loading capacity due to the friction caused by the uneven surface of the cable. Cable bolting is done before actual stoping from existing drifts, sublevel drifts, e.g. or from special bolting drifts. In general stress relieved steel strands are used; 2 x 15.2 mm dia per hole. FEM or BEM calculation is utilized in cable bolting design. Bolts 2 are in fan shape, 10 m ... 50 m long and are spaced 1/20 m ... 1/50 m2 at stope walls. Pretensioning of cable is not needed, when bolting is done before rock deformations. Bolting costs vary between 0.3 USD ... 1.0 USD/ore ton. In the beginning only manual cable installing technique bras used. Now bolting can be done as fully mechanized with the developed cable bolting machine; i.e. drilling of the hole, installing and cutting of cables and grouting of hole.

Jan 1, 1983

By B. R. Palmer, G. Gutierrez B., M. C. Fuerstenau

Selective flotation in nonmetallic systems is often complicated by the presence of iron-bearing silicates occurring as gangue. Minerals such as augite, diopside, hornblende, and tourmaline respond readily to flotation under the same conditions as ore minerals. Mechanisms by which these minerals respond to flotation with anionic collectors must be established if selective separations are to be made in these systems. It was the objective of this investigation to determine the mechanisms involved in the flotation of two pyroxenes, augite and diopside, with potassium oleate. Experimental Materials and Methods Pure potassium oleate, prepared by neutralization of oleic acid with KOH, was used as collector, while reagent-grade HC1 or KOH were used for pH adjustment. Conductivity water, made by passing distilled water through a mixed-bed ion exchange column, was used in this investigation. Two pyroxenes, [ ], were involved in this work. One member of this class of minerals was augite and was found to contain 3.3% calcium, 4.6% iron, and 9.6% magnesium. The source of this mineral was Tillamook County, Ore. The other pyroxene involved was diopside which contained 8.3% calcium, 2.7% iron, and 7.6% magnesium. The source of this sample was Bancroft, Ont. Microflotation experiments were conducted with a Hallimond cell. Mineral samples were ground dry and sized to 100 x 200 mesh. One-gram charges were conditioned for 3 min in the presence of various additions of potassium oleate. Flotation was conducted for 1 min with a nitrogen flow rate of 50 cm3/min. The electrophoretic mobilities of these two minerals were measured with a Zeta Meter in the absence and presence of [ ] salts and in the presence of an indifferent electrolyte, NaC1, added to maintain ionic

Jan 1, 1978

By M. T. Abasov

The work suggests an approach to the problem of optimally planning the drilling and development of gas fields. The approach is based on systems analysis and allows a joint optimal choice of the total number of wells in the field, their spacing in the reservoir, the diameter of production tubing, drilling dynamics, the number and spacing of drilling platforms and well pattern schemes for each plat- form as well. The optimal solution satisfies the set of technical- economical requirements and provides a minimum value of discounted total expenditures (capital costs plus operating costs). A mathematical model of the problem is presented. This work represents an extension of the authors&apos; previous investigations that formulated and solved problems of optimal drilling of oil and gas deposits by directional wells [1] and problems of optimal control of the number of active wells in multi-reservoir oil and gas fields [2], [3]. For construction of the mathematical model we choose a range (Nmin, Nmax) of possible values of the total number of wells, N, which should be drilled in the deposit. Here Nmin, Nmax are minimum and maximum numbers of wells correspondingly, that should be drilled into the reservoir. N[€](Nmin = N1, ... N[o], ..., Nm = Nmax). For simplicity a one-reservoir gas field is considered. It is assumed that: (a) wells are spaced in the reservoir uniformly, (b) there is a certain algorithm providing a uniform spacing of the given number N[o] ([0]=l, . . . , m) of wells in the reservoir, (c) the diameters of the production tubing for all the wells are the same. The relation Qz (x), i.e. the dependence of the cumulative output of gas from the cumulative "well-years" of operations is constructed for each diameter dZ from the given range of diameters d1< ...< dr.

Jan 1, 1977

By Walter L. Maxson, Fred C. Bond

THIS paper is a continuation of two earlier papers, l, 2 and presents new data on the grindability of various ores and other materials-the results of several years of intermittent research work on the nature of grinding and interpretation of test results. It is divided into five parts: 1. The tabulated results of several hundred grindability tests on a wide variety of ores. 2. A method of correcting screen analyses and calculating from them the surface and other properties. 3. A description of a new method of measuring the "surface energy" of an ore by pendulum impact tests. 4. Test results. 5. A general discussion of the test results and their application to grinding problems. 1. GRINDABILITY OF VARIOUS ORES This part is a continuation of the paper listed as reference No. 1. The method of testing is described in detail in that paper. The sample to be tested is crushed to all through 6 mesh in rolls set at x6-in. opening in closed circuit with a screen. Of this sample 700 C.C. is ground dry in a laboratory ball mill under constant conditions of mill speed and ball charge in closed circuit with a screen of the desired size at 250 per cent circulating load. The mill is cylindrical, 12 by 12 in., and rotates at 70 r.p.m. It contains a charge of 285 iron balls weighing 20,125 grams and ranging from 1 ½ to ¾ in. in diameter. Each test is continued for a sufficient number of periods to establish equilibrium at 250 per cent circulating load, or until the composition of the circulating load is constant for successive periods. Tests are conducted at the mesh size to which the ore is to be ground in practice, and the results are expressed as the net production in grams of screen undersize per revolution of the mill. This is designated as the

Jan 1, 1938

By Frank E. Neil, O&apos

The formation tester, as the name implies, is a tool built for testing the contents of sands encountered in drilling Wells Without actually cementing casing on the sand. The tester was developed in the Mid-Continent and has been in use commercially there since about 1926. However, some two dozen patents have been issued on formation testers dating back to the seventies. The method apparently was an outgrowth of the old Mother Hubbard grain or bean packer, used around casing before the days of cementing casing. These packers were also seated in a tapered hole and if the formation tested was not satisfactory the casing was pulled loose and the hole taken down to another formation. A great deal of experimental work has been done in its development, and as a result of this work the formation tester became an accepted integral part of the petroleum development in California. The formation tester was introduced into California some three years ago by M. 0. Johnston. Months of discouraging and expensive work followed its introduction into this state, but one organization after another tried the tool and its use is now fairly general. Shortly after Johnston began testing in California, the Halliburton tester was also introduced into the state and now another tool is being introduced, the Shaffer-Roles tester. Principle and Operation of Testers The principle employed in all formation testers is that of packing off the fluid in the hole above the formation to be tested and thereby prevent,ing it from having access to the testing tool. This permits the fluid contained in the given formation to have unrestricted access to the tool. It is accomplished by running the tool and packer on the bottom of the drill pipe; the valves in the tool being closed while going into the hole to prevent fluid from entering the drill pipe. The packer is then seated at the desired point, trapping the drilling fluid above it. When this has been done, the valves in the tool are opened and the fluid from the formation is allowed to enter the empty pipe through the tool. If the

Jan 1, 1934

By R. Hadfield

Since the writer has been intimately connected with the development of manganese steel for many yearsm some remarks upon the early work wutg regard to the rolling and forging of the material might be of interest…

Jan 1, 1915

By R. F. Domagala, M. Hansen, D. J. McPherson

Iodide zirconium was combined with calculated amounts of nitrided zirconium sponge and arc melted to prepare alloys in the 0 to 6 wt pct N region. Annealing treatments were carried out at 21 temperature levels. Metallographic examination of the heat-treated specimens permitted construction of the binary phase diagram from 0 to 6 pct N. Features of the diagram include the peritectic formation of both a and ß solid solutions. The maximum solubility of nitrogen is 0.8 pct in 8 zirconium and 4.8 pct in a zirconium. An X-ray study of nitrided materials was made in the range 6 to 13 wt pct N region because serious nitrogen losses were experienced when attempts were made to arc melt these high nitrogen alloys. PHASE relationships in the Zr-N system have been determined. Due to the inability to retain nitrogen in nitrogen-rich alloys subjected to arc melting, definitive work was possible only in the range 0 to 6 wt pct (0 to 30 atomic pct) N. Sufficient complementary X-ray work was done to permit construction of the binary phase diagram up to 13.3 wt pct (50 atomic pct) N (ZrN). Small ingots were prepared by arc melting master alloys with enough zirconium to produce an alloy of the desired composition. Following pretreatment, alloys were annealed at temperature levels between 600" and 2020°C. Determination of the phase boundaries was then accomplished by metallographic evaluation of specimens quenched from the various temperatures. Incipient melting techniques were used to corroborate solidus curves, and X-ray diffraction was employed to study the nitrogen-rich region of the a + ZrN phase field. Materials Westinghouse Grade 1 iodide zirconium crystal bar served as the base material for this investigation. The as-received bars were lightly sandblasted, pickled in a 20 pct HN0-5 pct HF aqueous solution, rinsed in water and acetone, and dried. They were rolled to about 1/32 in. strip and acid-pickled, followed by water and then acetone rinses. The material was sheared to approximately 1/4 in. squares, cleaned with acetone, and stored for use. Pure zirconium nitride is not commercially available, according to correspondence with possible suppliers. A literature survey indicated that nitrogen may be introduced into zirconium metal by passing nitrogen or ammonia gas over zirconium at an elevated temperature. After considerable experimentation, a train was devised whereby high quality nitrogen was passed through a series of bubblers to remove the last traces of oxygen, through an H,SO, bubbler and a cold trap to remove moisture, and finally over zirconium within a resistance furnace. Hand-picked Bureau of Mines magnesium-reduced zirconium sponge proved more amenable to nitriding than the crystal bar. The nitrogen used was extra pure gas purchased from Linde Air Products Co. The first two bubblers through which the gas was passed contained a solution suggested by L. F. Fieser" as being ideal for removing the last traces of oxygen from nitrogen. The solution contains 20 g KOH, 2 g sodium-anthraquinone ,9-sulphonate, and 15 g NaHSO, dissolved in 100 ml water. It is blood-red and turns brown when contaminated with oxygen. A saturated lead acetate solution, next in the series of bubblers, removed any H2S which might have formed in the 0, removal stage. An H,SO, bubbler and cold trap removed moisture before the nitrogen was passed over the zirconium. The zirconium was contained in a stainless steel screen within a Vycor or quartz tube in a resistance furnace. Unreacted nitrogen passed out of the system through a mercury bubbler. A nitriding run was performed in the following manner: Zirconium was placed in the screen within the furnace tube. The unit was assembled, suitably clamped off, and evacuated to remove the air and moisture within the tube and that trapped by the zirconium sponge. The unit was flushed with nitrogen and evacuated twice. After nitrogen was allowed to pass over the zirconium for about 30 min, the furnace was turned on; several hours were required to reach temperature. The reaction was allowed to continue at temperature for about 4 hr and the screen was then withdrawn from the hot zone of the furnace by means of a Nichrome or Kanthal rod. The screen and its contents were allowed to cool at the end of the tube and were then removed. At 800°C no more than about 5 pct N could be introduced into the sponge zirconium. This material was designated M-1 (master alloy No. 1) and reserved for the preparation of alloys in the dilute nitrogen region. A second set of experiments was conducted at 1000°C; no more than 7.2 pct N could be introduced into the zirconium at this temperature. Enough material (M-2) of this nitrogen content was prepared to produce a second set of alloys to complement the first and to provide alloys in the 0 to 6 wt pct N range. It was hoped that a diffusion anneal plus a re-nitriding might yield a material of higher nitrogen content. The material containing about 7 pct N was therefore given a homogenization treatment at 1000°C for 6 hr under an argon atmosphere. It was

Jan 1, 1957

By Eugene Coste

Although some of the observers who first paid especial attention to the occurrences of oil and gas in the strata (such as Hunt in 1859, Andrews in 1861; Winchell in 1865, Mendelejeff in 1876, Höfer in 1876, Minshall in 1881, and I. C. White in 1883) seem to have been impressed with the fact that oil and gas deposits were connected with the disturbances in the rocks caused by their upheavalll yet, with the exception of Mendelejeff, and possibly Andrews, these observers do not appear to have understood what is really the one essential factor in the occurrence of oil and gas in the strata: viz., the faulting, uplifting, fracturing, fis-suring, and jointing always accompanying even slight rock disturbances, and in certain districts (petroliferous provinces)2 allowing solfataric hydrocarbon emanations to force their way up from the interior and to reach and impregnate the porous portions of sediments subjected to the disturbances. Instead of this simple explanation to account -for the observed connection between petroleum deposits and rock disturbances, most of the observers mentioned above, and many others who have foliowed them on the same lines since, have entirely reversed the problem. To them, instead of the dissemination of gases from fissures into the sediments, it presented the accumulation and concentration, according to anticlinal or other geologic structures, of oil and gas originally present throughout the whole mass of the strata where they were produced by the decomposition or distillation of organic remains. Whether this important problem involves accumulation from sources within the strata themselves, or infiltration and dissemination from outside sources, may be easily determined if all preconceived ideas are put aside and the established facts only are considered. Physical Facts Sedimentary strata are composed of alternate beds of shales, sandstones, and limestones, most of which are sufficiently close-grained to

Jan 1, 1915

By Jay N. Fairbanks, Richard G. Robinson

This paper discusses a computer program and related formulas for fire fighting responses by coal mine personnel. The computer will interpret the mine air analysis, print reports, and provide relevant graphs allowing quick and accurate responses to coal mine fires.

Jan 1, 1983

By Frank C. Roberts

Progress in the facilities for handling mining products has been largely superinduced by the necessities of commercial economy ren dered requisite in order to meet the demand of competition. So rapid has been the depreciation in the value of mineral products, primarily due to the disproportionate increase of output over con sumption, that it may be justly claimed that mining, when considered as a commercial success, depends largely upon the ease and cheap ness by which the products are brought to the surface of the ground. In all methods of performing this operation, wire rope enters as an important factor; and the object of the present sketch will be to explain, as fully as is consistent with the space allotted, the various • adaptations of wire rope employed in placing coal and ores within the reach of our overground systems of transportation. These adaptations will be considered in the following order: I. Hoists. II. Inclined planes. a. Engine planes. b. Gravity planes. c. Aerial planes. III. Haulage. a. Tail-rope system. b. Counter-rope system. c. Endless-rope system. IV. Hoists. The term " hoist" is applied to the system whereby the mine product is elevated from the mine-level to the surface through ver-

Jan 1, 1888

By J. P. Zannaras

If we assume that testing of the model started at time t1, that time t2 was the instant at which the elastic limit of the material was passed at the points of the maximum stress, and that at time t3 the failure of the model was completed as shown in the typical photograph (Fig. I), then actually the photograph shows the final results of what took place between time t2 and t3. By the principle of similitude all conclusions drawn from the behavior of the model were applicable and valid for actual mine roofs up to the time t2 after time t2 motions and friction came into play during the destruction of the model. The events between t2 and t3 and the photograph itself are not representative of the events expected in an actual mine roof unless corrections imposed by the principle of similitude are made. It can therefore be stated that all conclusions and observations of the author from the photographs are applicable only to his small-scale experiments and not to actual mine roofs. Without investigation of the true stresses or the combined maximum stress induced in the beds it has been assumed by the author that failure occurred solely due to bending stress caused by loading of the beds. (The author states that D was taken to be the theoretical strain given by elementary beam theory.) Fig. 1 shows that the beds were clamped together. This clamping was necessary to prevent slipping of the beds due to the horizontal shear. However, this clamping caused an uncontrolled and undertermined com-pressive stress S at the end of the beds, and this com-pressive stress caused a true tensile stress ?S (? PoiS-son ratio). This true tensile stress combined with the tensile stress produced at the end of the beds due to loading (fixed beam uniformly loaded), and the horizontal shear which is maximum at the end appears to be the most probable maximum stress produced in the beds. It is therefore evident that the author in performing this experiment has introduced stresses in the model not existing or dissimilar to actual mine roofs, and therefore his conclusions may be applicable to his small-scale experiments but inapplicable to actual mine roofs. Louis A. Panek (author&apos;s reply)—The discusser&apos;s difficulty is related to mechanics of materials rather than similitude. The effect of time did not enter into the tests in any way, being simply excluded from consideration in this study, because all quantitative results entering into the design equations are based on measured (between time t1 and time t2) bending strains that are well below the breaking strain (i.e., in the elastic range) for the model material. Time does not become a significant factor until the rock stress reaches 80 to 90 pct of the breaking stress." The objective of this investigation was not to predict that bolted roof will fail after time t, but was instead to develop a safe roof, that is, roof in which the bending strain is much less than (say less than 50 pct of) the breaking strain. The models tested to failure had no direct bearing on the design equations. Although for some rocks time may influence the magnitude of stress or strain at which fracture occurs, breaking stress or breaking strain values were not employed for any purpose in this investigation. Tests to failure were made only to obtain additional evidence regarding the behavior of the bolted laminae&apos; as evinced by the locations of the cracks. As stated in the last paragraph of the paper, if one wishes to predict the time or stress conditions for which the roof will fail, additional information is required. The reason for clamping the laminae is to make them behave liked clamped beams, which closely approximate the clamped-plate condition of the actual mine roof beds (Ref. 5, p. 1; Ref. 6). The writer has previously demonstrated that the bending stresses induced by centrifugal loading in a clamped model beam are in agreement with those predicted by theory;&apos; hence clamping has no significant effect on the bending ,trains measured during a test. Moreover, actual ,in, roof beds are likewise subject to a clamping effect due to weight of superincumbent strata carried by the pillars or ribs on each side of the opening. It is emphasized that this study was restricted to evaluating only the reinforcing effect produced by the bolts. Procedures employed in the experiments and in the data analysis were such as to deliberately exclude the effects of other factors. The objections offered are therefore invalid,

Jan 1, 1957

By Luis Toron, Salvador Cortes-Obregon

John D. Price (Colorado Fuel and Iron Corp., Pueblo, Colo)—The paper on the coal fields of the Oaxaca district as prepared by engineers Toron and Cortes-Obregon of the staff of the Bank of Mexico bears witness to the thorough and careful way in which the men associated with this organization perform their work. There is little to be added to their paper in way of discussion other than to confirm and amplify some of their statements. Since the only extensive and well-developed field of coking coal lies in the northeastern section of the country adjacent to Sabinas in the state of Coahuila, it follows that blast furnace plants would be located in that same region. Two such plants are now operating at Monterrey and Monclova, using coke produced at the Sabinas district mines. But the nearer of these two plants is 600 miles from Mexico City and even farther from the center of population. Transportation of products from these mills to the market area is therefore expensive, both because of the distance and the difficulty of the terrain over which it must be carried. The development of an integrated steel industry closer to the center of population has therefore long been a goal toward which the Mexican technicians have been striving. While the presence of coal of some grade has been reported in many of the states, and many ideas have been advanced regarding its possible uses in iron and steel production, deposits of anthracite in Sonora and the various coals of the Oaxaca district as reported on in this paper are the only ones that have been explored in a serious manner. The coking coal from the Mix-tepec zone appears to offer promise of producing a coke which could be used in a standard blast furnace. Several problems are indicated, however: 1—The ash in the coal is high as mined, but indications are that it can be washed to an ash content of 15 pct with a recovery of 70 pct of washed coal. 2—Such washing would increase the volatile content from 17.4 pct to about 20 pct, and in a byproduct oven this should give a coke yield of close to 80 pct with an ash content of coke under 20 pct. 3—A free swelling index of 5 appears low for a good coking coal, and below that of the coals from the Sabinas district, which show between 6 and 9. But washing of the coal should result in an improvement in this regard; in the United States coals from Utah with an index even lower than 5 have made a usable coke. 4—A coal with volatile as low as 17.4 in raw coal and 20 in washed coal would come close to being classed as a low-volatile rather than medium-volatile coal, and low-volatile coals are notorious for their high expansion properties. Several plants in the United States are making coke from straight medium-volatile coal of 26 to 28 volatile content, and one at Rosita,, Mexico, from coal of 25 volatile. But no plants to my knowledge are using coal as low as 20 volatile. Since the Rosita coal appears to be a borderline coal from the angle of its expansion properties the coking of one of the straight lower volatile must be approached with caution. 5—There are few coals possessing any degree of coking properties which cannot be used in coke production by careful attention to its preparation and blending. The fact that coals of other types are available in this same region make improvement through blending very possible. 6—There are other workable methods of reducing iron ore other than the conventional coke-blast-furnace method. These will not be discussed here but it is known that their use has been considered. The technicians of not only Mexico but also of the other Latin American countries are keenly aware of their natural resources and their national needs. This paper emphasizes the fact that the Mexican technicians are working on their problem and attempting to speed the day of self-sufficiency for their country. Salvatore Cortes-Obregon (author&apos;s reply)—I wish to thank Mr. Price for his kind remarks. The Mixtepec coal as shown in Table II has 30 pct ash and a free swelling index of 5, but when the same coal is washed to 15 pct ash it has a free swelling index of 8 to 9 and the volatiles increased from 17.4 to 20.7 pct. A satisfactory coke has been produced from blends made in the Mexican laboratory using at least 40 pct of the Mixtepec coking coals with the other Oaxaca non-coking coals. Koppers in Germany report good coke obtained from the Oaxaca coal with a blend of 80 pct Mixtepec coal. Consideration is being given the possibility of using methods other than the conventional blast furnace for the reduction of iron ore near the Oaxaca area; electric furnaces appear promising. The non-coking coals could be used to produce cheap electric energy and the coking coals to make metallurgical coke.

Jan 1, 1955

By Carl Scholz

Discussion of the paper of Carl Scholz, published in Bi-monthly Bulletin, No. 22, July, 1908, pp. 551 to 559. HOWARD N. EAVENSON, Gary, W. Va. (communication to the Secretary*) :-For some time before the publication of Mr. Scholz&apos;s paper, I had been collecting data bearing upon its subject, and I now take pleasure in presenting my results to the Institute in the form of a discussion. It has long been a matter of common opinion among mining-men that mice-explosions are, more frequent during the colder, or winter months, than during the warmer ones, and it is a matter of common knowledge among them that the air-ways and road-ways in most mines are much drier and are more in¬clined to be dusty during the winter than during the summer. In many mines, places which are wet and sloppy in the summer are dry and sometimes dusty during the winter. These changes, of course, can only be due to atmospheric conditions, and are caused by differences in temperature and humidity. Until recently, however, very little attention has been paid to the part that atmospheric conditions may play in mine-explosions, or, rather, to the effect they may have in rendering mine-conditions peculiarly dangerous, and in spreading and rendering more disastrous the effects of what would otherwise probably have been .small explosions. To show the difference in mine-conditions during sunnier .and winter months, I have tabulated in Table I. the results of 24 observations of hygrometric conditions in several different mines at different times of the year. Mines Nos. 1, 2, and 6 are located in the Pocahontas.coal -region, in McDowell couuty, W.Va., the first one being a shaft-mine shaft mine and the others drift. Mines 1A and 2A are drift-mines located in Logan county, W. Va. All of these are mines of fair size, but none of them has been in operation more than six years,

Jun 1, 1909

By Henry M. Bates, Roscoe Pound

Mr. Chairman and Gentlemen: I accepted your Chairman&apos;s invitation to speak to a group of experts in this field with the greatest hesitation, because I know little or nothing about it. Certainly I can make no detailed suggestions, or suggest planning along very definite lines. You cannot do that sort of thing in a vacuum, and as I have suggested, my knowledge of the whole oil problem is next to nothing. It is possible that as a student of our public law, constitutional law particularly, for a number of years, I have acquired a perspective that may enable me to offer, for what they are worth, some general thoughts on these problems. I think that nothing in the whole field of law requires more definitely and clearly the functional approach than does the problem of a sound legal solution of the difficulties of the oil and gas industry. The industry is dealing with substances that are peculiar, and one must know how those substances act and what has been the history of the industry, to undertake to make anything like specific suggestions. I certainly am not qualified.

Jan 1, 1935

By E. V. Potter

For a nurnber of years, it has been known that manganese made by electro-deposition under certain conditions is ductile while under other conditions it is very brittle. The ductile metal is gamma manganese normally stable only between 1100 and 1138°C1; the brittle metal is alpha manganese, stable up to 727OC. The ductile metal is not stable, but gradually changes to the brittle form; the time required to complete the transfornlation is about 20 days at room temperature. Other observations have indicated that the transformation is completed in 10 to 15 min. at about 125°C, while at — 10°C, no appreciable change occurs in 9 months. The properties of gainma and alpha Illanganese in the pure state are ordinarilj difficult to determine because the gamma structure cannot be retained by normal quenching procedures and alpha manganese is so brittle, it is difficult to obtain specimens free from flaws. In a recent investigation2 some properties of gamma and alpha manganese were determined by studying the ductile electrolytic metal and determining the changes in its properties as it transformed to the brittle alpha form. These investigations provided an excellent opportunity for following the progress of the transition and studying its mechanism. The results of a series of such investigations are reported in this paper. Procedure Various properties of manganese were determined starting with the metal in the original ductile gamma form and following the subsequent changes in its properties as the metal transformed to the brittle alpha form. These observations were made at various temperatures, the data providing information regartling the mechanism of the transformation as well as the effect of temperature 011 the transition rate. Structure and resistivity values gave the most significant results, so this paper is concerned primarily with them. The structure was studied microscopically as well as by X ray diffraction. The resistivity was determined on strips of the metal by measuring the potential drop across a given length of the specimen. Current was passed through the specimen by wires soldered to its ends, and the potential connections were made by wires looped around the specimen near its center. The current was determined by the potential drop across a standard resistor connected in series with the specimen, the potential drop being measured on a potentiometer. In the temperature range from room temperature to 100°C an ordinary drying oven was used to heat the specimen. This was entirely satisfactory except at 100°C, where the time required to heat the specimen was long compared to the transition time, making the initial section of the resistivity curve unsatisfactory. To overcome this limitation, at 100°C and higher a thermostatically controlled oil bath was used to heat the specimens. The block on which the specimen was mountetl was plunged into the hot oil at the start of each test. The heating time was thereby reduced from 5 min. to about 6 sec, and dependable resistivity values could be obtained through 160°C. At this point the whole transition, including the warm-up time for the specimen, required only about 20 sec and it was not considered worth while trying to extend the temperature range further. Aside from the heating problem, the problem of making a sufficient number of accurate resistivity determinations became more and more difficult as the temperature was raised. Using the manually operated potentiometer, 100°C was about as far as it was possible to go. At this temperature and above, a self-balancing photoelectric recording potentiometer was used. Its response was quite rapid, and it proved to be entirely satisfactory all the way through 160°C, where the tests were stopped because of the specimen heating problem rather than any limitation of the potentiometer recorder. The metal used in these tests was prepared at the Salt Lake City laboratory of the Bureau of Mines. The method of preparation is discussed in a paper by Schlain and Prater.3 The sheets were about 2 3/8 by 5 3/16 in. and varied from 10 to 16 mils in thickness. They could be cut readily into pieces suitable for the various tests. X ray and microstructure determinations were made on pieces about 1/8 to 1/4 in. wide and about 1 in. long, while resistivity measurements were made on strips as long as possible and about 55 in. wide. The thickness of each sheet was not uniform over all its surface. This had no bearing on the X ray and microstructure determinations, but sections as nearly uniform and free from flaws as possible were chosen for the resistivity determinations. The gamma manganese was electro-deposited at 30°C, the time of deposition ranging from 5 to 12 hr for each sheet. Whenever possible, the tests were started directly after the metal was stripped from the cathode; otherwise the sheet was placed immediately

Jan 1, 1950

By H. E. Cline

Calculations of the formation and growth of faults caused by a variation in lumellar widths were made for a two-dimensioml three-plate problem. The angle between the a-ß boundary and the growth direction was allowed to vary and the time evolution was studied using a quasisteady state approach. At spacings smaller than a critical spacing given by X V = AO variations in the larrlellar widths grow in time to produce faults that coarsen the structure, while at spac-ings larger than this critical spacing, variations in the lamellar widths decay in time. If small plates are introduced into the structure they may grow only at large spacings to refine the structure. The time evolution and shape of faults were calculated for the three plate-problem and then the three dimensional problem and rod-like eutectic were qualitatively discussed. UNDERSTANDING of the mechanism by which the spacing of directionally solidified eutectics is determined may allow one to control their structure better. Steady state solutions for the growth of lamellar structures have been found for a range of lamellar spacings A and growth velocities V. To obtain a unique solution for the isothermal growth of pearlite, Zener1 assumed that growth occurs at a maximum velocity, while Tiller2 assumed that a eutectic alloy, grown under an imposed velocity, will choose a spacing corresponding to minimum undercooling. These assumptions are equivalent and have been referred to as "extremum growth". The extremum condition predicts the observed relation between velocity and spacing as given by V = constant [I] but does not provide a mechanism for changing the lamellar spacing. Jackson and Hunt3 calculated the interface shape by using solutions to the diffusion equation for a planar interface and a relation of the interface composition to the local curvature. If the spacing is much larger than the extremum spacing, the interface breaks down catastrophically to form forked plates. However, the catastrophic breakdown cannot account for the small adjustments in spacing that must occur in practice..3 Direct observations during the growth of organic eutectics4 and the Pb-Sn eutectic5 show that spacing changes occur by the formation of faults. A fault in a plate-like eutectic is the edge of a plate. Once the faults form, they may move to make small adjustments in the spacing.6,3 The motion of faults intersecting the growing interface was shown by an approximate analysis to give Eq. [I].6 A perfectly regular lamellar structure should be able to persist over a range of lamellar spacings. However, during growth small perturbations in the structure may occur. If the amplitude of the perturbation increases in time the structure is unstable, while if all possible perturbations decrease in time the structure is stable. In a previous paper7 variations in the shape of the solid-liquid interface were considered, while this paper considers only variations in lamellar widths while maintaining a macroscopically planar solid-liquid interface. Previously, theories of lamellar growth1"3 have artificially contrained the growth to give a regular periodic structure. To allow for a variation in spacing, the three phase intersections and groove angles were allowed to change with time as determined by assuming local equilibrium. THREE-PLATE PROBLEM Since the spacing changes in eutectics by local formation of faults,4&apos;5 it is suggested that local variations in spacing are responsible. The interaction between neighboring plates will be greatest because they have the smallest diffusion distance. For simplicity, as a nearest neighbor approximation, a three-plate problem will be considered, as illustrated in Fig. 1. The structure consists of a periodic array in which all the plates are allowed to vary in width. As in steady state growth it is assumed that the average composition in the solid remains constant. A variation in plate widths, that maintains the composition in the solid, was introduced by making the first a-phase plate thinner by an amount A, keeping the width of the second B-phase plate constant, and increasing the width of the third a-phase plate. If the structure were not perturbed, as in the regular two-plate problem previously described,&apos; then the groove angles at the three-phase junctions are the equilibrium angles, 0, and ? B, and the solid-solid boundary is normal to the interface. In the three-plate problem with a variation in plate widths the phase boundaries are assumed to be related to the three-phase junction by equilibrium angles, but the a/B boundaries may be rotated by an angle 0 from the growth direction. The angle H be-tween the tangent to the a/B boundary and the growth direction may vary during growth and determine the —> — — —.A_ Q-0 / 0 x, X2 Fig. 1—Schematic of the three-plate problem showing a variation in the spacing and the effect on the angles at the three phase intersections.

Jan 1, 1970

By J. T. Norton, N. J. Grant, A. R. Chaudhuri

MOST of the recent work to establish the mech-anism of creep in metals at high temperatures has utilized aluminum as the experimental material. It was thought desirable to initiate an investigation of a hexagonal close-packed metal, because of the relatively simple slip system, and compare the observed deformation characteristics with those that have been observed for the face-centerd cubic metals. High-purity magnesium was chosen for this purpose, first, because its strength and other mechanical properties are similar to those of aluminum in the same temperature range, and second, because the existing equipment was ideally suited to observe magnesium during creep. It is proposed in this paper to present a pictorial and qualitative account of the changes that high-purity magnesium undergoes during creep at 500°F. The characteristics of deformation of aluminum described below have been observed by various workers and accounts of these may be obtained from the papers of Chang and Grant.&apos;- These characteristics are: slip, subgrain formation, grain boundary sliding and migration, fold formation, deformation bands, and kink bands. It is well known that in a flat magnesium specimen, slip on the basal plane (0001) in the [1120] direction results in the formation of straight bands on the surface of the specimen. Schmid and co-workers&apos; have shown that this system is operative in the temperature range of -185" to 300°C (-300° to 572°F). They have also shown that a second system, slip on the pyramidal planes {1071} or {1012} in the [1120] direction, is operative at temperatures higher than 225°C (437°F). Between 225° and 300°C (437" to 572°F), therefore, deformation by both these systems is expected. Bakarian and Mathewson5 confirmed the occurrence of pyramidal slip on the {1011} plane and found that it resulted in irregular markings on the surfaces of their specimens. Burke and Hibbard6 obtained evidence of pyramidal slip in single crystals of magnesium deformed at room temperature. Bakarian and Mathewson5 suggested that the irregular appearance of these bands was due to slip on both of the pyramidal planes occurring simultaneously but in the same direction, the close angular relationship between the planes making this process possible. Furthermore, since neither of these planes is close enough to the basal plane, slip on the latter does not exhibit the irregular appearance of slip bands resulting from pyramidal slip. Experimental Procedure High-purity magnesium, supplied by the Dow Chemical Co., was used in these experiments. The analysis was as follows: Al, 0.0002 pct; Mn, 0.0018; Fe, 0.0024; Cu, 0.0002; Sn, 0.001; Ca, 0.01; Ni, 0.0003; Zn, 0.01; Pb, 0.0005; Si, 0.001; and Mg, 99.972. The magnesium was supplied in the form of 1/2 in. diam rods. The specimens had an overall length of 21/4 in., the round ends being threaded to fit the specimen holders. The previously round 3/16 in. diam gage section of the specimen had two parallel flats machined on opposite sides for microscopic observation, yielding a test zone having the dimensions of lx3/16x7/64 in. The specimens were electrolytically polished (without prior mechanical polishing of the machined flats), in a solution composed of 375 ml of ortho-phosphoric acid and 625 ml of ethyl alcohol.&apos; The cathode was a stainless steel sheet bent so that the specimen was completely surrounded. The voltage for successful polishing was 1.5 v at 100 to 300 milli-amp current. Electropolishing for about 45 min sufficed to obtain a good metallographic surface on the specimens after they had been machined. The creep tests were performed under constant load, and two types of equipment were used. In the first, designed by Servi and Grant,V he specimens were beam-loaded, and a furnace could be lowered to surround the specimen. As the microstructural changes could not be observed during the course of the test, the tests had to be interrupted periodically by removing the specimen for microscopic examination. The second unit was a high temperature microscopy furnace designed by Chang and Grant.&apos; The furnace was fitted with an optically flat quartz window having area dimensions 1.25x0.5 in., so that the whole test portion could be viewed through it at magnifications up to x240. The metallurgical microscope had three mutually perpendicular axes of motion, and, in addition, it was possible to measure angular displacements by rotation of the eyepiece. It was thus possible to make precise observations of the specimen during creep, and micrographs could be taken by attaching a camera to the eyepiece of the microscope. The average grain size of the specimens that were tested was about 1 to 3 mm. This grain size could

Jan 1, 1954

By Y. S. Bonillas

Page I. Introduction.......................... 286 II. Physiography.......................... 286 : 111. Introductory Geology...................... 287 IV. Rocks of the District ...................... 288 (A) Sedimentary Rocks..................... 288 Pinal Schist ........................ 288 Bolsa Quarteite....................... 289 Abrigo Limestone...................... 290 Capping Quartzite..................... 291 Martin Limestone...................... 292 Escabrosa Limestone .................... 295 Naco Limestone....................... 296 Cretaceous Deposits..................... 296 Glance Conglomerate................... 296 Morita. Mural and Cintura Formations........... 297 (B) Igneous Rocks........................297. Pre-Cambrian Granite.................. 297 Pre-Cretaceous Granite Porphyry............. 298 Rhyolite........................301 Other Dikc Rocks.................... 301 V. Structural Geology........................ 304 General Structure of Mule Mountains............. 304 Fault Blocks and Other Divisions............. 304 Igneous Rocks...................... 312 Copper Queen Block..................... 313 Fault Blocks...................... 313 Intrusions....................... 315 Don Luis Block....................... 315 Intrusions and Orebodies................. 316 VI. Geologic History......................... 316 VII. Metamorphism and Mineralization................. 318 General Metamorphism.................... 318

Jan 1, 1917

By H. H. Evinger, M. Muskat

A method has been developed whereby one may calculate the productivity factors of producing formations from a knowledge of the reservoir conditions. Account is taken not only of the heterogeneous character of the gas-oil flow system but also of the detailed variations with pressure of the shrinkage and viscosity of the oil, the solubility of the gas in the oil, and even the variability of the gas viscosity and the deviation of the gas from ideal behavior. Curves are shown giving the results of numerical calculations on the production rate as a function of the pressure differential for a high-prcssure and a low-pressure system, three values of gas-oil ratio being treated in each case. Curves are also given showing the variation with distance from the well of the pressure, oil saturation, and permeability. The effect of connate water is briefly discussed in relation to the apparently large discrepancies between the calculated and observed productivity-factor values. Introduction The significance of the productivity factor as a measure of the capacity of an oil-bearing formation to produce is well recognized; for it is the composite and integrated resultant of the physical prop-crties of both the porous medium and the fluid stream passing through it with respect to the ease with which the particular petroleum fluids present in the formation can flow through it and into producing wells. The most direct method of determining the productivity factor of a well consists, as is well known, in the simultaneous measurement of reservoir-pressure differentials and rates of production and the expression of the data in terms of rate of flow per unit pressure drop.&apos; Actual measurements carried out in this manner on producing wells have given factors that generally lie in the range of o to Ioo bbl. per day per pound pressure drop. This wide range arises not only from variations in permeability but also from the varying sand thickness of producing formations. One of the aims of developing a theory of the mechanics of oil production obviously is that of predicting what the productivity factor should be from a knowledge of the individual characteristics of the producing formation and the fluids produced. For homogeneous fluid systems passing through a porous medium into a producing well, it has been known for some time that the steady-state rate of liquid flow Q is given by the formula:* Q ? u log r?/r? where k is the sand permeability, h its thickness, µ the liquid viscosity, ?p the pressure drop between the well and the distant parts of the reservoir, in particular that at a radius re, and r? is the well radius. This gives the productivity factor: f= Q/kh?p ? 2p/µ log re/r? f=Q/ kh?p ? 2p/µ log re/r? which will have a numerical value for a

Jan 1, 1942

By M. Muskat, H. H. Evinger

A method has been developed whereby one may calculate the productivity factors of producing formations from a knowledge of the reservoir conditions. Account is taken not only of the heterogeneous character of the gas-oil flow system but also of the detailed variations with pressure of the shrinkage and viscosity of the oil, the solubility of the gas in the oil, and even the variability of the gas viscosity and the deviation of the gas from ideal behavior. Curves are shown giving the results of numerical calculations on the production rate as a function of the pressure differential for a high-prcssure and a low-pressure system, three values of gas-oil ratio being treated in each case. Curves are also given showing the variation with distance from the well of the pressure, oil saturation, and permeability. The effect of connate water is briefly discussed in relation to the apparently large discrepancies between the calculated and observed productivity-factor values. Introduction The significance of the productivity factor as a measure of the capacity of an oil-bearing formation to produce is well recognized; for it is the composite and integrated resultant of the physical prop-crties of both the porous medium and the fluid stream passing through it with respect to the ease with which the particular petroleum fluids present in the formation can flow through it and into producing wells. The most direct method of determining the productivity factor of a well consists, as is well known, in the simultaneous measurement of reservoir-pressure differentials and rates of production and the expression of the data in terms of rate of flow per unit pressure drop.&apos; Actual measurements carried out in this manner on producing wells have given factors that generally lie in the range of o to Ioo bbl. per day per pound pressure drop. This wide range arises not only from variations in permeability but also from the varying sand thickness of producing formations. One of the aims of developing a theory of the mechanics of oil production obviously is that of predicting what the productivity factor should be from a knowledge of the individual characteristics of the producing formation and the fluids produced. For homogeneous fluid systems passing through a porous medium into a producing well, it has been known for some time that the steady-state rate of liquid flow Q is given by the formula:* Q ? u log r?/r? where k is the sand permeability, h its thickness, µ the liquid viscosity, ?p the pressure drop between the well and the distant parts of the reservoir, in particular that at a radius re, and r? is the well radius. This gives the productivity factor: f= Q/kh?p ? 2p/µ log re/r? f=Q/ kh?p ? 2p/µ log re/r? which will have a numerical value for a

Jan 1, 1942