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By Hugh S. Spence

In the winter of 1941-42, muscovite mica was discovered by a young prospector, Justin Purdy, in the township of Mat-tawan, Nipissing District, Ontario, a few miles north of the small settlement of Eau Claire, which lies on the main Transcontinental Highway (No. 17) between Mattawa and North Bay. Muscovite had been known for many years to occur in the general Mattawa region, and various small efforts at production had previously been made by individuals working scattered deposits in the area. These minor activities, however, had never led to production of any consequence or the discovery of any important mica bodies. The Purdy finds were made in a heavily timbered, mountainous area lying about three miles north of the low-lying settled land along the highway, and in a section not hitherto prospected. The mica taken by Purdy and two partners from surface outcrops proved so remarkable in point of size of trimmed sheets that the find attracted considerable attention, and the area surrounding the three claims taken up by the prospectors was quickly blanket-staked by various interests. Though a number of other mica-bearing pegmatite dikes were found later on these stakings, none proved as rich as those on the original Purdy ground; very little commercial mica was obtained from them and attempts to develop them were short-lived. Purdy and his partners sold their initial production to dealers in Ottawa and Hull, where the Canadian mica industry long has centered. Young Purdy, unfortunately was killed in a motor accident in the early summer of 1942. His father continued mining operations for a few months and produced and sold a considerable amount of mica. In October 1942 the Purdy holdings were acquired by lnspiration Mining and Development Co. of Amos, Quebec, which had been active in staking in the area. This company formed a subsidiary, Purdy Mica Mines, Limited, to develop the property. Under the energetic management of Joseph R. Norrie, rapid progress was made, and production soon attained important proportions. Realizing from the outset the unusual character and potential value in the war effort of the Purdy discovery, the Metals Controller, Department of Munitions and Supply, at once arranged with the Department of Mines and Resources for an official geological report on the area, and also drew the attention of the War Production Board in Washington to what seemed likely to prove a highly important source of strategic-quality mica. Officials of WPB were sent up in the Summer of 1942 to inspect the property, and so impressed were they with the possibility that it might become of high

Jan 1, 1948

By D. D. Lambert, E. C. Simmons

Rare earth element (REE) analyses of cumulus plagioclase from the PGE ore zone of the Stillwater Complex indicate that pressure fluctuations in the magma chamber acting on a single magma cannot be responsible for features such as the reappearance of Mg-rich olivine on the liquidus. The data are more consistent with a model involving multiple injection and mixing of geochemically distinct magmas. The PGE-bearing sulfides of the J-M Reef are associated with such a reappearance of olivine, indicating that the unusual location of the ore zone may be related to the addition of new magma, compositionally distinct from magmas that produced cumulates in the Ultra- mafic zone of the complex.

Jan 1, 1984

By Ionel I. Gardescu

In connection with some of the experiments carried out by the writer on the behavior of gas and oil in a sand reservoir,' an interesting phenomenon was observed which may throw some new light on the problem of recovery of oil from a natural reservoir. The experiments are intended to show the effect of the surface area of the occluded gas masses, originally present in a reservoir, on the further evolution of gas from the oil and its consequent effect upon the rate of production of oil. The apparatus used in the experimental work is shown in Fig. 1. It consists primarily of a sand reservoir R and a displacement chamber D, which is used to induce small variations in volume. The reservoir and displacement chamber form a unit, and a lowering of the plunger D is equivalent to increasing the volume occupied by the oil and gas in the reservoir. The reservoir was first filled with dead oil and maintained under pressure until it was ascertained that most of the free gas had gone into solution. The volume of free gas present in the reservoir was computed from the coefficient of compressibility of the fluids by means of the displacement chamber D, reading to 0.005 c.c. and a special gage J reading to 0.02 lb. per sq. in. The oil was saturated with gas under pressure in reservoir S by circulating the oil for a long period of time through the gear pump B. Subsequently, the saturated oil was circulated through the sand reservoir following the circuit S6, B, S6, R4, the sand reservoir R, R1, R², F4, F1, back to reservoir S. In the following experiments the sand reservoir R was filled with gas-saturated oil at a pressure of 415Ib. per sq. in. with no free gas present. This was ascertained by closing off all the outlet valves and determining the coefficient of compressibility of the system by means of the displacement chamber D. Much difficulty was encountered in eliminating all of the free gas masses from the oil reservoir. The dead oil originally present in the

Jan 1, 1932

By M. Muskat, R. D. Wyckoff, H. G. Botset

The flow of liquids through porous media is known to follow Darcy's law which states that the velocity of flow is proportional to the pressure gradient. This law is but a statement of the facts obtained from experimental studies and is, therefore, uncontroversial. It should be men-tioned, however, that it applies only when the flow is viscous in nature and that at excessive velocities which tend to produce turbulence, the velocity is proportional to some power of the pressure gradient, the exponent ranging from 1 to 0.5 as the degree of turbulence increases. However., experiments with media having permeabilities corresponding to those of actual producing horizons show conclusively that the actual flow of liquids in a producing horizon must be viscous except perhaps in the immediate vicinity of a well producing at a high rate. Therefore, one is justified in assuming Darcy's law to hold for cases of practical interest, as will be implicitly assumed in this discussion Given this basic law of flow it is possible, theoretically to obtain solutions to any problem of viscous flow of dead liquids1 by the usual methods of potential theory. However, problems of practical interest often present such complex geometrical configurations of sources and sinks (driving sources and output wells) as to make the analytical solutions extremely difficult or even impossible. It is useful, therefore, to note that Darcy's law is precisely equivalent to the law of electrical conduction, so that the pressure distribution in steady state porous flow of liquids is exactly the same as the potential distribution in an electrical conducting medium.2 This analogy permits the use of electrical models wherein the potential distributions may be measured with far greater facility and accuracy than is possible in actual fluid-sand models. Such electrical models were used in determining the pressure distribution about complex arrays of wells, an example of which will be shown later in the discussion of the 5-spot flood. One phase of the porous flow problems which is of considerable practical interest involves the tracing of an advancing fluid front. Thus,

Jan 1, 1933

By A. G. H. Andersen, A. W. Kingsbury

SILICON bronzes containing iron are used to a considerable extent in industry, under the trade name of P.M.G. alloys. Various classes of wrought alloys fall in the composition range 1.5 to 3.5 per cent silicon, and 0.5 to 2.5 per cent iron. Castings may contain as much as 6 per cent silicon and 3 per cent iron at present. The constitutional diagrams of these alloys are thus of considerable practical importance. Copper-silicon-binary alloys have been thoroughly investigated by a number of workers, the latest reports being those of C. S. Smith1 and of A. G. H. Andersen.2 Although much work has been done on iron-copper alloys,3 recorded investigations on the copper-rich copper-iron binary constitutional diagram are not numerous. Tammann and Oelsen4 determined the solubility limits of iron in copper by means of magnetic measurements, and found that the solubility of iron in copper amounts to a fraction of one per cent at 400°C., increasing slowly to one per cent at 800°C. From 800°C., the solubility increases rapidly and attains 4 per cent at 1100°C. Hanson and Ford,5 using electrical resistivity measurements and the microscope, determined a somewhat different solubility limit. Of earlier X-ray works on the copper-iron system, very little has been published. The work by Bradley and Goldschmidt6 on copper-iron-aluminum alloys includes some information on the copper-iron binary. These investigators conclude that substitution of iron in the copper lattice decreases the spacings, which is contrary to the evidence of the present work. Hanson and West7 have investigated the ternary alloys of copper with iron and silicon. Although their diagrams are valuable contributions to the understanding of these alloys, they did not recognize the kappa phase,12, 7,8 and their diagrams do not everywhere conform to the phase rule. The present work contains a check by means of X-rays of the solid solubility limit of iron in copper, and an X-ray investigation of the ternary-phase diagram, which, owing to present conditions, it became necessary to curtail considerably. PREPARATION OF SAMPLES Castings weighing about 75 grams were melted under vacuum. The charges were made up of ingot iron, copper cathodes from Laurel Hill, and refined silicon supplied by the Electrometallurgical Co. Alundum crucibles were generally used. The exceptions were alloys 77 and 78, which were melted in graphite crucibles. The ingots were annealed at 800°C. for one week, then samples were cut for chemical analysis. Longitudinal sections of the binary alloy ingots were hammered into plates 3 in. thick. Wherever possible, these plates were homogenized at temperatures ensuring

Jan 1, 1942

COMMITTEES. Precious and Base Metals. Charles W. Goodale, Chairman.. L. D. Ricketts, Vice-Chairman Darsie C. Bard, Secretary, Montana State School of Mines, Butte, Mont. Leonard S. Austin, Thomas J. Grier, Willet G. Miller, David W. Brunton, Hennen Jennings, Albert F. Schneider, Theodore B. Comstock, Edmund B. Kirby, George C. Stone, Stanley A. Easton, Charles W. Merrill, Benjamin B. Thayer. Samuel S. Fowler,

Jan 11, 1913

By Hans Conrad, W. D. Robertson

FORMAL theories of yielding and flow have been developed to describe thermally activated plastic flow in metal crystals.'-" hey are all based on Becker's' original idea that thermal fluctuations aid the applied stress in overcoming internal barriers to flow and lead to the following relation. where j is the strain rate; C is a constant which includes a frequency factor, the entropy, the number of flow units, and the amount of strain associated with each successful fluctuation; E(T) is the activation energy associated with flow, and is a decreasing function of the applied stress, 7; k is Boltzmann's constant; and T is the temperature in OK. The various theories differ mainly in the model chosen and in the nature of the relationship between the applied stress and the activation energy. Beckerl and Orowan' suggest a relationship of the form E a(Ti — t)2, where .ri represents the stress required for flow without the aid of thermal fluctuations; Kauzmann,3 Cottrel1,5 and Seeger6,7 suggest E a(t — t) ; Fisher8 suggests E while Cottrell and Bilby4 suggest a more complex relationship between E and 7. Additional data are needed to test these various theories., esweciallv- in view of Dorn's9 ork. which indicates that the activation energy for creep is independent of the stress and strain. The present paper presents the stress-strain data derived from incremental loading of magnesium single crystals in tension and direct shear, in the temperature range of 78" to 364°K. Incremental loading was employed in order that the creep component of the strain could be determined. Stress-strain curves of aluminum10-13 and copper" single crvstals. derived from incremental loading tests, have been found to be in agreement with those obtained by the more conventional constant strain rate or loading rate tests. Two types of tests were conducted in the present investigation: 1) tests in which the temperature was maintained constant throughout the entire

Jan 1, 1958

The performance of a two-horizon depletion-type reservoir produced through combination wells is analyzed. By introducing some simplifying approximations, it has been possible to obtain formulas which are easy to handle. Only ordinary differential equations are used, and the development of the analysis can be followed without difficulty by the non-specialist. A rigorous analysis has been made of this problem. It has been found that the approximations introduced in the simplified analysis are fully justified and that errors seldom will be more than 2 per cent. The report shows the effect of the rate of withdrawal upon the relative depletion of the two horizons. Numerical examples are given. INTRODUCTION In its simplest form an oil reservoir consists of a continuous, homogeneous body of porous and permeable rock, enclosed at the top and the bottom by impermeable material. The flow of fluid through such a reservoir has been the subject of numerous papers, and the mathematical analysis of well performance, pressure build-up, etc., has reached a high degree of refinement. One of the basic assump tions introduced into these analyses is the homogeneity of the reservoir. In non-homogeneous reservoirs, these computations still can be carried out satisfactorily, provided small irregularities in the physical properties of the rock are distributed in a random fashion. The flow equations are derived as solutions of the continuity equation, and their solutions are dependent upon the assumption of many constant factors in the reservoir: permeability to oil, compressibility of the reservoir fluid, viscosity saturation, etc. When these axe assumed to be constant, the continuity equation can be solved rigorously. When these assumptions do not hold and corrections are introduced, it becomes very difficult and often impossible to solve analytically. The present analysis is concerned with production from a two-layer depletion-type reservoir in which the layers have different permeabilities. Instead of using the continuity equation, results were derived from some simple physical ideas. In a single-layer reservoir in which the oil is at a pressure above the bubble point, the rate of production often has been assumed to be directly proportional to the pressure drawdown. In the simplified analysis it has also been assumed that the drop in average reservoir pressure is directly proportional with the cumulative withdrawal. These considerations in the past have been the basis of the analysis of reservoir performance and have been applied to a variety of problems, often with marked success. In the problem under investigation these relationships are shown to be compatible with the equation of continuity, but the approach has the advantage of leading to ordinary differential equations in which changes in constants can be introduced without making the analytical solution impossible. It has the additional advantage that it can be understood more readily by the large group of engineers who are not reservoir specialists. For that reason, detailed steps in the mathematical developments have been shown in full. SCOPE OF ANALYSIS The analysis in this paper has been applied to a two-layer depletion-type reservoir in which both horizons are produced simultaneously in the same well. Because of the difference in permeability, it is obvious that the depletion of the two zones will proceed at different rates. For various problems it may be of interest to know the degree of depletion of the two zones at any arbitrary time and to in-

By W. Jolley

Decarburized iron and Fe-3.28 pct Ni alloys were impact and tension tested in the temperature range of ambient to 4°K. It was found that alloying with nickel improves the fracture properties of the ferrite matrix. The improvement in toughness of iron alloyed with nickel is attributed to the effect of the nickel addition on the temperature and strain rate dependence of the yield stress as well as on slip behavior. The Fe-Ni alloy exhibits wavy slip when strained at temperatures down to at least 50°K. This behavior contrasts with that of the unalloyed iron where a change It is a generally accepted fact that of the common alloying elements of steel only nickel and manganese improve both the room-temperature yield strength and the notch impact properties. It has been argued for a number of years that manganese refines the ferrite grain size, the pearlite spacing, and the grain boundary carbides in medium- and low-carbon steels and thereby increases resistance to brittle fracture.''' This hypothesis recently was confirmed for a 0.04 pct C iron containing manganese, but at the same time from wavy to planar slip occurs at about 120°K. The observed lower temperature and strain rate dependence of the lower yield stress in the Fe-Ni alloy as compared to the unalloyed iron may be attributed to this difference in slip behavior. In contrast to suggestions published previously, transmission electron microscopy showed that the uniform dislocation distributions and the lack of dislocation tangles which are produced by low-temperature straining of bcc materials cannot be attributed to the absence of cross slip at these temperatures. no increase in notch toughness was observed in a decarburized Fe-Mn alloy.3 It thus appears that manganese only increases the toughness of Fe-Mn-C alloys by refining grain boundary carbides and has no toughening effect in carbon-free iron. On the other hand, the mechanism whereby nickel improves toughness has not been established. Hodge et a1.4 have clearly shown that a 3.28 pct Ni addition lowers the impact transition temperature of 0.02 pct C steel approximately 35°C when the grain size is maintained constant. Recently, Wullaert and Tetelman6 stated that nickel refined the grain boundary carbides of an Fe-C alloy and consequently increased the toughness. They also observed the previously reporteda-'

Jan 1, 1969

By H. S. Martin

Although it was known some years ago at the Utah Copper Co. mills that fine grinding improved flotation recoveries, no accurate data were available until recently as to just how far the grinding could be carried economically. In 1923 the ultimate degree of fineness for flotation feed was supposed to be about 10 per cent. on 65 mesh, with approximately 55 per cent. through 200 mesh, which meant that most of the mineral would pass 100 mesh. At this time Garfield and Wilfley tables were used ahead of flotation and a good deal of the coarse mineral removed prior to the ball mill regrind. Shortly afterwards, mill-scale tests developed the fact that on a feed containing not over 10 per cent. +65-mesh material flotation alone would give a copper recovery equal to that obtained by the combination of tables and flotation, but that on much coarser feed the recovery with flotation alone was lowered. This was at a time when all the sulfide minerals were floated if possible, so that the only requisite was to grind fine enough to free the mineral from gangue. Earliest Use of Microscopic Examination of Tailings As early as 1921, the writer had attempted to determine by chemical analysis the relative proportions of copper minerals in tailings from an ore that made extremely poor flotation results. Chemical analysis was not satisfactory or conclusive, and samples of these tailings were sent to the U. S. Bureau of Mines Station at the University of Utah for microscopic examination. The question at that time was to determine, if possible, which copper minerals had been lost and why, but R. E. Head, in his report, revealed other interesting data. He said in part: Briefly stated, the mineral partieles or grains may be classified into scparate groups as follows: 1. Free grains of pyrite, chalcopyrite, chalcocite and bornite, respectively, which contain 110 other included sulfides; 2. Grains in which all three of the copper sulfides are representel (the core may be of chalcopyrite, partially altered to boruite, these two minerals being cntirely surrounded by a shell of chalcocite); 3. Grains composed of equal amounts of bornite and chalcocite or chalcopyrite and chalcocite. The grains of free mineral particles are perhaps the most numerous, taking the ore as a whole, but it is noticeable that of the grains of combined or associated sulfides

Jan 1, 1930

Gerald Sherman, Bisbee, Ariz. (written discussion*) .—The fact that, after a change in the hours of labor, as much work is found to be done in 8 hr. as was accomplished in 10, probably results from the more rigid examination of operating methods that is made when the management faces new and more difficult conditions. Although A better working pace will prevail, most of the gain will result from economies of plan and only a part of it from the improved effciency of labor. The Iabor of shoveling is so severe that it may be easily believed that a working period of less than 7 hr. will give maximum results, but there arc many other occupations about a mine in which this is not true, and in which the rate of accomplishment is in proportion to the time employed, up to 9 or 10 hours. Mr. Harley's study of shoveling has becn thorough, and demonstrates the benefit of investigation and education even in such simple work, but his reference to methods of payment opens a subject even more important in mine management. The efficiency of labor may be excellent, but unless a method of equitable payment accompanies it, the result will be only temporary. With strict but sympathetic supervision, a good average day's work can be obtained; but with the exception of those unusual men who cannot be restrained from working to their limit, an average daily wage does not bring out the remarkable performance of which many men are capable. There is also a considerable variation in the average amount accomplished, dependent on the supply of Iabor. This can readily be shown by any labor record that covers several periods of shortage or superabundance of labor. An increase in the daily wage in the time of labor shortage does not necessarily bring out an increased day's work; there is usuaIly a decrease in labor efficiency at such times regardless of the wage, whenever a daily rate is used. Rewards to individuals for exceptional performance appearing as an increased rate of pay cannot be made in a large organization without bad feeling. In a small organization, an individual's ability may be so well recognized that different rates of pay can be applied. Exceptional work can only be obtained by a method of payment based on the valuable results accomplished. As a basis for such payment, an

Jan 1, 1920

By Bruce W. Gonser, Robert I. Jaffee

Recent work by the authors1 established the constitutional diagram of the gold-germanium system. Of particular interest in the simple euctectiferous system was the eutectic alloy at 12 per cent Ge, which melted at the very low temperature of 356°C and had an unusually fine eutectic structure. It was of interest to investigate the effect of third components on the melting point, microstructure, and strength of this alloy, and in this work the effect of copper is discussed rather completely, with less complete data on the effects of silver, platinum, nickel, and zinc. No reference in the literature has been found on ternary systems with gold-germanium. Materials and Alloying -4s in the work on the binary system, gold-germanium, the germanium used in this investigation was the cyanide-reduced, 99.9 per cent product, produced by the Eagle-Picher Co. Fine gold sheet from Handy and Harmon, pure platinum sheet from the American Platinum Works, copper magnet wire from Anaconda, nickel wire assaying 99.6 per cent Ni. and electrolytic zinc were used for alloying. To make the alloys, charges of the pure metals were put in a graphite crucible and melted in an atmosphere of pure hydrogen. The temperature was brought up to about I050 C, and the metal allowed to freeze in the crucible. Except with alloys containing zinc, melting losses were consistently less than a few milligrams. When zinc was a component, weight losses up to half the weight of the zinc present were incurred, and the alloy compositions were calculated by assuming the entire weight loss to be that of zinc. In all other cases the composition of the alloys could safely be taken as that of the charge. The ingots, as solidified, were segregated, the heavier primary phases being at the bottom and sides of the ingots and the lighter primary phases at the top, but by sectioning the entire ingot vertically for microscopic examination, this factor could be evaluated. Ingots for microscopic examination weighed one gram, and those for thermal analysis weighed three grams. Thermal Analysis In this work, the eutectic line composition and thermal arrests were desired, and, after microscopic exploration had established the position of the eutectic line at a given percentage of the third component, a thermal analysis was run at that composition. The method of thermal analysis used in the work on the binary Au-Ge system,' a method particularly well suited for a small quantity of material, was used in this work. Clearly defined arrests were obtained, although with some alloys containing platinum

Jan 1, 1946

By Robert I. Jaffee, Bruce W. Gonser

Recent work by the authors1 established the constitutional diagram of the gold-germanium system. Of particular interest in the simple euctectiferous system was the eutectic alloy at 12 per cent Ge, which melted at the very low temperature of 356°C and had an unusually fine eutectic structure. It was of interest to investigate the effect of third components on the melting point, microstructure, and strength of this alloy, and in this work the effect of copper is discussed rather completely, with less complete data on the effects of silver, platinum, nickel, and zinc. No reference in the literature has been found on ternary systems with gold-germanium. Materials and Alloying -4s in the work on the binary system, gold-germanium, the germanium used in this investigation was the cyanide-reduced, 99.9 per cent product, produced by the Eagle-Picher Co. Fine gold sheet from Handy and Harmon, pure platinum sheet from the American Platinum Works, copper magnet wire from Anaconda, nickel wire assaying 99.6 per cent Ni. and electrolytic zinc were used for alloying. To make the alloys, charges of the pure metals were put in a graphite crucible and melted in an atmosphere of pure hydrogen. The temperature was brought up to about I050 C, and the metal allowed to freeze in the crucible. Except with alloys containing zinc, melting losses were consistently less than a few milligrams. When zinc was a component, weight losses up to half the weight of the zinc present were incurred, and the alloy compositions were calculated by assuming the entire weight loss to be that of zinc. In all other cases the composition of the alloys could safely be taken as that of the charge. The ingots, as solidified, were segregated, the heavier primary phases being at the bottom and sides of the ingots and the lighter primary phases at the top, but by sectioning the entire ingot vertically for microscopic examination, this factor could be evaluated. Ingots for microscopic examination weighed one gram, and those for thermal analysis weighed three grams. Thermal Analysis In this work, the eutectic line composition and thermal arrests were desired, and, after microscopic exploration had established the position of the eutectic line at a given percentage of the third component, a thermal analysis was run at that composition. The method of thermal analysis used in the work on the binary Au-Ge system,' a method particularly well suited for a small quantity of material, was used in this work. Clearly defined arrests were obtained, although with some alloys containing platinum

Jan 1, 1946

By Norman Brown, J. V. Rinnovatore

It was found that a shear stress applied during the recovery had no effect on the amount of recovery if the stress was less than the instantaneous yield point irrespective of the direction of the stress. Large ajplied stresses during recovery had a marked effect, which depended on the direction of stressing. Single strain reversals at -72°C not only produced the Bausch-inger effect but also increased the flow stress. The increase inflow stress was attributed to vacancies, which have appreciable mobility at -72 °C. THEORIES I-' of recovery suggest that the internal stress field of the dislocations plays an essential role. Most investigations of recovery use time and temperature as the independent variables; however, here stress has been introduced as a variable in two ways: 1) by varying the internal stress field according to the amount of strain prior to recovery and 2) by applying an external stress during recovery. Tannen- baum and Kauzrnann studied the effect of applying a stress during recovery by measuring the change in creep rate after recovery; they found that stresses as high as 95 pct of the creep stress had no effect on recovery. Earlier, Wood and scrutton6 showed that an applied stress during creep increased the rate of poly-gonization. The experiment by Wood involved poly-crystalline aluminum whereas Tannenbaum and Kauzmann used a single crystal of zinc. In this investigation, zinc single crystals were used and deformed in a manner to prevent polygonization. Thus, the main difference between this investigation and that of Tannenbaum and Kauzmann is the use of the stress-strain curve instead of creep rate as the index of recovery. In addition, the applied stress during recovery varied

Jan 1, 1961

By H. L. Sheakley, D. J. Coolidge

This paper does not deal with all sands used in the glass industry in Missouri; it covers only that used in the plate-glass factory at Crystal City. However, it is probably safe to say that other sands, pro- duced throughout the state for this purpose, are of identical nature. The glass sand used in Missouri is cornrnonly called the St. Peter deposit, which is ascribed to the Ordovician Rock series in the form of sandstone. This St. Peter deposit, aside from a few small outliers, covers a large area of eastern Missouri. It forms, through a broad curve, the northeast margin of the typical Ozark region between Cape Girardeau on the southeast and Mineola, Montgomery County, on the northwest. The belt is extremely irregular, varying from one to ten miles in width; its length is 150 miles in a straight line. The outcrop near the entrance to the Crystal City mine appears in the form of a sandstone bluff approximately 30 ft. high, running along Plattin Creek (Fig. I). Above the sand rock an overburden of Joachim limestone appears, which thickens to nearly 300 ft. and forms the hill commonly called Buck Knob. Test holes where drilled at various points and the drillers' log indicate that the St. Peter deposit ranges in thickness from 63 to 71 feet. Properties of the St. Peter Sand From an analysis of the glass sands of the St. Peter formation in Missouri, the follow-

Jan 1, 1948

By D. J. Coolidge, H. L. Sheakley

This paper does not deal with all sands used in the glass industry in Missouri; it covers only that used in the plate-glass factory at Crystal City. However, it is probably safe to say that other sands, pro- duced throughout the state for this purpose, are of identical nature. The glass sand used in Missouri is cornrnonly called the St. Peter deposit, which is ascribed to the Ordovician Rock series in the form of sandstone. This St. Peter deposit, aside from a few small outliers, covers a large area of eastern Missouri. It forms, through a broad curve, the northeast margin of the typical Ozark region between Cape Girardeau on the southeast and Mineola, Montgomery County, on the northwest. The belt is extremely irregular, varying from one to ten miles in width; its length is 150 miles in a straight line. The outcrop near the entrance to the Crystal City mine appears in the form of a sandstone bluff approximately 30 ft. high, running along Plattin Creek (Fig. I). Above the sand rock an overburden of Joachim limestone appears, which thickens to nearly 300 ft. and forms the hill commonly called Buck Knob. Test holes where drilled at various points and the drillers' log indicate that the St. Peter deposit ranges in thickness from 63 to 71 feet. Properties of the St. Peter Sand From an analysis of the glass sands of the St. Peter formation in Missouri, the follow-

Jan 1, 1948

By W. R. Crane

The effect of mining in the red-ore mines of the Birmingham district has been observed for some time, but, except in a few localities, little difficulty has been experienced from disturbance of cover. Cave-ins near the outcrop and fracturing of the surface at greater distances are the most pronounced manifestations of disturbance, while limited areas at points distant from the outcrop and under greater depth of cover have actually subsided. were it not that the orebed is overlain by one or more water-bearing formations, the fracturing or settlement of the surface would not be serious; but because of these formations, fracturing of the top rock may in itself be of sufficient importance to warrant the adoption of protective measures. Further, the collapse of pillars over a wide area may develop squeezes that, if not controlled, may jeopardize the integrity of the mines and necessitate a change in development, from slopes to vertical shafts, at a much earlier period than is now contemplated. Drainsge in these mines has been discussed in papers on mining practice,' but the fact that water, varying from 0.16 to 3.46 and averaging 1.43 times the amount of ore mined, has to be pumped from the mines daily, indicates the importance of the problem and the advisability of making a thorough investigation of the source of mine water, its mode of entry into the mines, its effect upon mining conditions, and consideration of means of improving the conditions.

Jan 1, 1927

By Richard H. Rein, John Chipman

Liquid slags of the system SiO2-Ca0-MgO-A1~03 were equilibrated with liquid Fe-Si-C alloys in graphite or Sic crucibles at 1600°C in pure CO gas at atmospheric pressure, and the silicon content of both phases determined. Ternary slugs of the systern SiO2-CaO-A12O3 were also studied at 1550°C. The silicon content of the metal phase saturated with both graphite and SIC is 22.0pct at 1550°C and In the iron blast furnace, as in nearly all carbon-reduction processes, some silicon is transferred from slag to metal. The importance of this reaction is enhanced by its indirect effect on the transfer of sulfur from metal to slag, and this has stimulated a comprehensive research program on the equilibrium distribution of silicon between slag and metal. Earlier studies'-3 of this same problem provided data for calculation of the thermodynamic activities4 of the components in SiO,-CaO-A1,O3 slags. 22.4 pct at 1600°C. The temperature at which the phases cristobalite, gvaphite, $ SiC, liquid slag, Fe-Si-C alloy, and CO gas at 1 atm pressure can coexist in equilibrium was found to be 1533°C. The results agree well with earlier studies. They are shown graphically as lines of constant silicon cmtent in the metal which also are lines of constant SiO, activity in the slag.

Jan 1, 1963

By C. D. King

The key to maximum production of ingots for the war effort is maximum production of pig iron. For any given furnace and ore, the most important single influence on blast-furnace production is the quality of the furnace coke. It is generally recognized that undoubtedly deterioration of Pittsburgh coking coals will be accelerated by the depletion of some of the better grades of coal; the extension of mine mechanization, with attendant degradation of coal quality; and the opening of new coal fields, some of which are known to be fairly high in sulphur. All of these factors, contributing as they do to higher ash and sulphur, and not infrequently to inferior quality of coke, made it desirable that an extensive study be undertaken to determine the effect of washing some coals that closely approximate the average chemical composition of coking coals to be expected in the future, by the subsidiaries of the United States Steel Corporation in the Pittsburgh district. It was deemed advisable to study the improvement obtained by washing such coals and to determine the need for supplementing the existing coal washery at Clairton to assure continued maximum production of pig iron from presently available furnace stacks. The existence of the cog! washer at Clairton made ii possible to conduct tests on coals used in raw form and on similar coals after washing. This study covers an investigation of the quality of furnace coke as affected by washing coking coals, and is confined to the use of IOO per cent high-volatile Pittsburgh seam coals from Fayette and Greene Counties in the manufacture of furnace coke. It covers the improvement in chemical and physical properties as well as the degree of uniformity in coke obtained by washing these coals, and includes the effect on blast-furnace production and practice. The test period involved is four months; the plants, Clairton by-product coke plant, and the Carrie No. I and No. 2 blast furnaces at Rankin, Pa., Carnegie-Illinois Steel Corporation. Clairton By-product Coke Plant and Coai, Washer The Clairton by-product coke plant carbonizes 30,800 net tons of coal daily in 22 batteries containing 1482 ovens. Three oven sizes are used, commonly known as wide, medium, and narrow types, recognizing the difference in oven width. These ovens also differ in height and length. The present coal washer has a daily capacity of approximately 14,000 tons, leaving I6,800 tons to be carbonized in raw form. Washed coal is used on all the narrow ovens and on three of the six batteries with ovens of medium width, raw coals being used pn all the remaining ovens. The customary arrangement is 7

Jan 1, 1944

By C. D. King

The key to maximum production of ingots for the war effort is maximum production of pig iron. For any given furnace and ore, the most important single influence on blast-furnace production is the quality of the furnace coke. It is generally recognized that undoubtedly deterioration of Pittsburgh coking coals will be accelerated by the depletion of some of the better grades of coal; the extension of mine mechanization, with attendant degradation of coal quality; and the opening of new coal fields, some of which are known to be fairly high in sulphur. All of these factors, contributing as they do to higher ash and sulphur, and not infrequently to inferior quality of coke, made it desirable that an extensive study be undertaken to determine the effect of washing some coals that closely approximate the average chemical composition of coking coals to be expected in the future, by the subsidiaries of the United States Steel Corporation in the Pittsburgh district. It was deemed advisable to study the improvement obtained by washing such coals and to determine the need for supplementing the existing coal washery at Clairton to assure continued maximum production of pig iron from presently available furnace stacks. The existence of the cog! washer at Clairton made ii possible to conduct tests on coals used in raw form and on similar coals after washing. This study covers an investigation of the quality of furnace coke as affected by washing coking coals, and is confined to the use of IOO per cent high-volatile Pittsburgh seam coals from Fayette and Greene Counties in the manufacture of furnace coke. It covers the improvement in chemical and physical properties as well as the degree of uniformity in coke obtained by washing these coals, and includes the effect on blast-furnace production and practice. The test period involved is four months; the plants, Clairton by-product coke plant, and the Carrie No. I and No. 2 blast furnaces at Rankin, Pa., Carnegie-Illinois Steel Corporation. Clairton By-product Coke Plant and Coai, Washer The Clairton by-product coke plant carbonizes 30,800 net tons of coal daily in 22 batteries containing 1482 ovens. Three oven sizes are used, commonly known as wide, medium, and narrow types, recognizing the difference in oven width. These ovens also differ in height and length. The present coal washer has a daily capacity of approximately 14,000 tons, leaving I6,800 tons to be carbonized in raw form. Washed coal is used on all the narrow ovens and on three of the six batteries with ovens of medium width, raw coals being used pn all the remaining ovens. The customary arrangement is 7

Jan 1, 1944