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By J. W. Leonard, B. A. Donahue

A method is described for incorporating coal petrography into mining and preparation plant quality control based on conventional analyses. Complete analyses are made of each of the uniform and relatively distinct petrographic bands in a coal face. With this information it is possible to develop petrographic standardization curves. These curves permit diverse coal characteristics to be rapidly monitored by application of a few standard coal tests. Single seam quality control is discussed in this paper. Inquiries continue to be made about coal petrography, and specifically, about whether coal petrography should be applied more extensively in the coal industry. Coal petrography is the study of the distinct physical, optical, and chemical increments which make up the organic rock mixture which we know as coal. Petrography can be applied by any coal company or at any coal mine where conventional coal analytical facilities are available and where additional resources can be allocated for an increased number of determinations. This first paper of a two part series includes (1) a proposed conventional approach to single seam petrography based on the development of petrographic standardization graphs and (2) some informative and supplemental interrelationships involving coal characteristics developed as a result of this research. In the second part of this series, to be published at a later date, those petrographic characteristics of bands taken from many different coal seams located over wide geographic areas which can be closely related to each other will be considered. These findings will be examined looking toward the development of a comprehensive, conventional approach to coal petrography which can be used as a common basis for multi-rank petrographic standardization graphs. Implicit to the understanding of coal petrography is the well established fact1,2 that the individual analyses of distinct petrographic bands often differ widely from the average analysis which is used to characterize a whole coal seam. In fact, a distinct and minor banded increment of coal in a high volatile seam may actually be a medium or low volatile coal with an analysis similar to the average analyses of seams located in distant coal fields. During the mining of coal, much degradation is caused which tends to randomly scatter coal bands. The degraded, scattered, and physically separated constituents of distinct petrographic bands are processed side by side in the coal preparation plant as distinct petrographic fractions with particles grouped according to a narrow size range (which derives in part from common hardness), specific gravity, and-or surface chemistry. Tile data obtained from numerous analyses made on each of the bands of any given coal seam, although diverse, can be readily interrelated. Indeed, these interrelationships can be developed into a series of nomographs or petrographic standardization graphs to serve as a basis for developing a conventional petrographic* program. Thus, by analyzing one property (for example, ash) of a selected petrographic fraction collected or separated from the flow of coal in a preparation plant, it should be possible to estimate the other physical, chemical, and thermal properties of this fraction by referring to the petrographic standardization graphs. It follows that any or all petrographic fractions in the total coal flow originating from a single coal seam can be rapidly monitored for many properties on the basis of a single analysis run on each fraction. In recent years coal petrographic research has concentrated heavily on that phase of this work which involves microscopic reflectance measurements made at many minute and selected points on a coal briquette surface.3,4 Thus, the percentage of the total number of reflectance measurements that fall into each of a consecutive series of arbitrarily chosen reflectance classes are used to characterize coal. This procedure is analagous to using the face of a coal briquette to represent the reflectance characteristics present at the face of a coal seam. Moreover, by analyzing petrographic fractions of known and uniform optical properties it is possible to closely relate reflectance to other coal characteristics. For example, reflectance has long been known to be related to such

Jan 1, 1968

By J. Gordon Parr, M. J. Bibby

In addition to the (bcc) - (cph) transformation at 882°C a second distinct change of slope has been observed on a titanium cooling curve between 905" and 960°C.1,4 Duwez,1 commenting on work by McQuillan,2-4 attributed this arrest to contamination of the specimen with oxygen—a possibility that existed even at the reduced pressure of 10-5 mm Hg at which the experiments were conducted.

Jan 1, 1963

By E. F. Ketterer, D. B. Collyer, A. B. Wilder

The microstructural stability of 59 carbon and low alloy steels after 34,000 hr exposure at 900' and 1050°F, including the weld heat-affected zone, is discussed. The tensile and creep rupture properties of the parent metal of many of the steels before and after 10,000 hr exposure are presented. SEAMLESS pipe has been used for many years at elevated temperatures. When seamless first began to be used, operating temperatures and pressures were relatively low and the steel produced adequately met the existing requirements. The need for knowledge of creep properties and graphitiza-tion was nonexistent. Today the requirements for tubular products have changed considerably. Operating temperatures and pressures are increasing continually and corrosion, particularly at high temperatures, presents a problem. Carbon steels have, under these conditions, certain economic advantages particularly in oil refinery use. However, the use of low alloy steels in the generation of steam power has increased appreciably due to the influence of molybdenum on creep strength and the control of graphitization with chromium. The behavior of carbon and certain low alloy steels after long periods of exposure at 900° and 1050°F (480° and 565°C) has been investigated. The steels were examined before and after 10,000 to 34,000 hr exposure. Results obtained with material exposed at 1200°F (650°C) are not presented due to the severe oxidation and resulting decarburiza-tion after long periods of exposure. The graphitization characteristics of carbon and low alloy steels are of fundamental concern to the users of these materials. This is particularly true where welded joints are employed. In order to evaluate properly the behavior of steels at elevated temperatures, it is desirable to employ not only long periods of exposure under controlled conditions, but to use material with known properties and steelmaking practices. The purpose of this investigation has been to study the microstructure of the weld and the tensile and creep rupture properties of the parent metal after long periods of exposure at elevated temperatures. In the report'.' of a previous investigation data were presented on the microstructure, impact strength, hardness, and oxidation characteristics after 10,000 hr exposure at elevated temperatures. When this investigation was planned, methods for controlling the graphitization characteristics of steel were not established and, therefore, a number of special alloy steels were included in the study. During the exposure of these steels, the influence of aluminum in accelerating the rate of graphitization and the inhibiting power of chromium were established by various investigators. Also, the vanadium-bearing steels, because of their outstanding creep properties, received attention. As a result of these developments, considerable progress has been made in the field of high temperature tubular products, and the necessity for special alloys to prevent graph-itization has been restricted largely to the use of chromium. Material Chemical analysis, deoxidation treatment, and austenitic grain size of the 59 steels discussed in this paper are shown in Table I. The steels were forged to 1x1 in. bars with the exception of steels 12B, 12DX, 12DY, 12DZ, 70, 70A, 72 to 78, 82, and 83 which were machined from heavy wall pipe. All bars were surface ground before exposure. Heat treatment before exposure is shown in Table 11. The majority of the steels included were melted in either a basic open hearth or basic electric furnace; how-

Jan 1, 1955

By Ralph L. Erickson

The discovery of a Carlin-type gold deposit at Cortez, Nevada, in 1966 can be attributed directly to the use of geochemical exploration techniques. Most mineral deposits owe their discovery to geologic concepts, geologic analysis, and luck, but at Cortez, geochemistry as an exploration tool played the clearly dominant role in discovery. Of course, the economic significance of the discovery had to be determined by exploration and development drilling. The story of the discovery began in 1959 when field work was initiated on a new project, "Geochemical Halos Utah and Nevada," by R.L. Erickson and A. P. Marranzino for the US Geological Survey. The Cortez district was selected for geochemical work because it was an area with good geologic control where we could address the problem of how to prospect in barren outcrops for concealed ore deposits in potentially favorable structures (buried thrust zones) or favorable host rocks in the subsurface. Geologic mapping of the Cortez 15-min quadrangle, just being completed by Gilluly and Masursky (1965), showed that the quadrangle contained excellent exposures of both the upper and lower plates of the Roberts Mountains thrust fault, a major structural feature of north-central Nevada. Roberts (1960) had noted that a number of mining districts were associated with windows in the thrust. In 1959, Erickson and Marranzino did some reconnaissance rock sampling and spring-water sampling in the siliceous clastic rocks of the upper plate of the thrust. Results of this reconnaissance prompted a full-scale sampling program in 1960 in the upper plate rocks on the west flank of the Cortez window. Results of the investigation showed that anomalously high concentrations of metals occur in the upper plate rocks, and further, that the distribution of metals is fault controlled and shows a pronounced zoning pattern (central copper zone; intermediate zinc, copper, and lead zone; and outer arsenic zone). The anomalies were interpreted as primary leakage halos that originated from metal occurrences in the thrust zone or in carbonate rocks below the thrust and moved upward along normal faults that cut both upper and lower plate rocks. Erickson gave a talk about these anomalies in the summer of 1961 to the local AIME Section in Reno, Nevada; two short reports were published that year-" Geochemical Anomalies in the Upper Plate of the Roberts Thrust Near Cortez, Nevada" (Erickson et al., 1961) and "Hydrogeochemical Anomalies in Four Mile Canyon Near Cortez, Nevada" (Erickson and Marranzino, 1961). These releases prompted blanket staking in the area by several small companies. In 1963, geologic and geochemical mapping were started by the USGS in the lower plate carbonate rocks of the Cortez window west of the quartz monzonite stock at Mount Tenabo and north of the old townsite of Cortez. The results of the work showed anomalously high concentrations of arsenic, antimony, and tungsten in jasperoid, fracture filling, and shear zones in Silurian and Devonian carbonate rocks. The anomalous area was about 1.6 km (I mile) long and 300 m (1000 ft) wide. A brief report, "Geochemical Anomalies in the Lower Plate of the Roberts Thrust Near Cortez, Nevada" (Erickson et al., 1964a), was published in 1964. During this same time period, 1959-1964, several exploration or mining companies were active in the general area (chiefly mapping geology and acquiring property). In 1964, American Exploration and Mining Company (Amex) concluded that the entire Cortez district was worthy of an extensive exploration effort involving drilling as well as geologic, geophysical, and geochemical studies. To carry out the program, Amex formed a joint venture group with the Bunker Hill Company, Vernon Taylor, Jr., and Webb Resources. Their early efforts were directed to the upper plate rocks and to the lower levels of the old Cortez silver mine. The group also drilled some shallow rotary assessment holes adjacent to the area of the arsenic, antimony, tungsten anomaly in lower plate carbonate rocks described in Erickson et al. (1964a). Assay results from these holes offered little or no encouragement to the joint venture group. Splits of these drill samples were made available to the USGS. In order to enhance any metal content present in these rocks and to determine the mineral residence of any metals detected, heavy-mineral concentrates of each 3-m (10-ft) sam-

Jan 1, 1985

By M. A. Steinberg, J. Wulff, R. Kamm

In a previous paper1 from this laboratory, the development of a lead grid method for exploring the distribution of strain and density within metal powder compacts was described. In that work thin lead foil with rectangular holes cut at regular intervals was inserted with the powder fill, the arrangement pressed and then radiographed to permit measurement of the deformation of the lead grid. Densities at each grid element obtained in this manner were plotted as a function of the die dimensions. From such plots it was found that the densest part of a compact pressed from one side (the top) is at the top outer region and the least dense at the bottom outer region of the specimen. The axial density maximum occurs more often nearer the bottom than at the top. As a result of such exploratory measurements, it appeared reasonable to conclude that variations in density could be attributed in the main to die wall friction. Thus compacts of large diameter appeared relatively uniform in density except where the die fill had been uneven. Finally it was found that lubrication of the finely finished die cavity contributed more to magnitude and uniformity of density within the compact than interparticle lubrication. Since publication of the above results, it was found that circular-hole grids could be more accurately made and, when deformed within the powder, more readily measured and analyzed. Much of the former work was repeated and new results which include the effect of lubrication, compact height, pressure, speed of pressing and vacuum pressing are reported in the present paper. Circular-hole Grids and Analyses OF Radiographs Commercial lead sheet 0.008 in. in thickness was used in all the work reported. The 0.0938-in. diam holes were punched in the sheet on 1/8-in. centers to an accuracy of 0.001 in. The finished grid used contained eight or more holes in a row and from I to 24 rows. The lead sheet was clamped between two pairs of brass strips bolted to a small milling machine table which was itself bolted to a bench in correct position near a vise which held the punch. Travel of the lead grid in two dimensions was controlled by two steel lead screws calibrated in 0.001-in. divisions. A stripper plate was used on the punch to avoid distortion of the lead foil. A high carbon-high chromium (chrocar) one-piece steel die was used throughout the work. The die cavity was 1.125 in. in diam and the clearance between plungers and die wall was 0.001 in. The die was also used for pressing from both ends with two long plungers. Finally, lapping of die and plungers gave a surface whose rms value On an Abbot profilometer was 5 micro-in. The die walls and plungers were, except where otherwise noted, lubricated with a stearic acid suspension in benzene. This was put on in multiple layers and allowed to dry before filling the die.

Jan 1, 1949

By J. Jones-Parra, J. C. Calhoun

INTRODUCTION The purpose of this paper is to present the results obtained by solving the fractional flow' and frontal advance' equations to obtain oil recovery at water breakthrough as a function of the length of the system being flooded, the linear velocity of injection and the displacing phase viscosity. The method of solution makes use of the stabilized zone concept first presented by Terwilliger, et al3 when calculating saturation distributions in a gravity drainage system. In order to check the calculated results, the equations and method of solution were applied to the system on which Rapoport and Leas' reported experimental data. METHOD OF SOLUTION The solution of the fractional flow equation and the frontal advance equation is obtained by assuming that a water front forms to sweep the oil out ahead of it. There is ample evidence that under the proper conditions a water 'front does form. If this water front is not to dissipate, the water saturations which comprise it must have equal linear velocities. These water saturations are said to comprise the stabilized zone. Equation (2) indicates that for all these saturations and hence fw must plot as a straight line against saturation for those water saturations comprising the stabilized zone. The water saturations lying between the highest in the stabilized zone and the highest that can be achieved in the porous medium comprise the variable zone. Regardless of the numerical value of the length of the system, the variable zone must eventually span all of it, so that for long enough systems in Equation (1) will be small enough to be neglected. Hence, for the saturations in the variable zone Equation (1) can be simplified to In order to determine the composite fw function applicable to the entire range of saturations in the porous medium, it is necessary to find the water saturation which separates the stabilized zone from the variable zone. This dividing saturation must be on the curve defined by Equation (4), and a tangent curve at that point must pass through the initial water saturation to satisfy Equation (3). Hence, the valid fw curve is given by a straight line starting at the initial water saturation, tangent to the curve of Equation (4): and along the curve of Equation (4) from the point of tangency on. The point of tangency determines the water saturation dividing the zones. The length and shape of the stabilized zone can be found by solving Equation (1) for Integrating this expression numerically between any two saturations in the stabilized zone gives the distance separating these two saturations. By repeated integration, the saturation distribution of the stabilized zone can be determined. The total length of the stabilized zone is given by The integral appearing in Equation (5) is a function of the viscosity ratio, the capillary properties of the rockfluid system, the relative permeabilities, and the initial water saturation. Considering these variables fixed and designating the value of the integral by writing caw for and v/60 for q/A; Equation (5) becomes The saturation distribution of the stabilized zone can be integrated over its length and divided by the length to obtain the average water saturation The volume of water in the stabilized zone is then given by The average water saturation in the variable zone can be found by extending the straight line segment of (the segment joining Sw and Sw) until it intersects fw = 1.00. The saturation at the intersection is. This method of finding is nothing more than the graphical solution of the equation The volume of water in the variable zone at breakthrough is then given by Assuming no initial water saturation, the recovery at breakthrough expressed as percent pore volume is given by

Jan 1, 1953

By J. A. Capp

For certain classes of electric railways a steel conductor is preferable to the oldcr atld more commonly used overhead trolley-wire. The third-rail presents a rather better appearance, because of the absence of an overhead structure; it is easily installed, cheaply maintai~ied, presents s large area for conducting and collecting the current, and is therefore particularly suitable for high speed and heavy service. With costs calculated on the basis of equal coilductirity in rail aud trollej-wire, the third-rail constrrictiol~ is cl~caper than thc overhead trolley. But the average interurban road will lise a trolley-wire of considerably less conductivity than would be obtained with the smallest size steel rail (about 60 lb. per pard) that mould ordinarily be used, and here the first clost of trolley construction would generally be less thau that of the third-rail. While no third-rail installation has jet bee11 in operation long enough to give figurcs of value, it ~vould appear that the cost of maintenance of the thirdrail construction should be less than that of the overhead trolley. This consideration, together with that of sightliness and adaptability (particularly in the case of terminals, yards and very heavy or high-speed service), will frequently off'set the higher cost of the third-rail construction and make it the preferable means of' conducting the current from thc generator to the car-motor. For the first third-rail installations, old track rails were used when obtainable, and these old rails were supple~rlented with new rails of standard T-section and composition. With the coming of the very heavy, high-speed service during the past few years, the resistance of these old and new standard T-rails was found to be so high that they mould not carry the high currents necessary without too great a drop in the line-potential. The rails would, therefore, have to be suppleme~~ted with addi-

Jan 1, 1904

By D. L. Albright, G. A. Colligan

An investigation has been conducted to determine the nature of the crystallographic substructure of nickel and a 1.0 wt pct Ag-Ni alloy which had been undercooled 105°C prior to solidification. A rotating back-reflection X-ray technique and modified Weissmann diffractometer were used to orient single-crystal sections from these poly-crystalline ingots and to determine the substruc-tural features of these single crystals, The sub-grain size in the pure nickel ingot is 0.5 mm diam while the silver-doped nickel subgrain size is only 0.1 mm diam. The misorientation between adjacent subgrains is approximately 1 deg of arc in both ingots, and the spread of orientation of sub-grains about the mean orientation of the crystal is 5 deg of arc in both ingots. The addition of silver results in a stable impurity substructure which is preserved during isothermal solidification and subsequent cooling to room temperature. In the absence of silver the initial impurity substructure is destroyed by dislocation interactions which produce a secondary substructure which grows to a size five times larger than the initial substructure. THE process of undercooling a metal entails cooling of the molten sample below the equilibrium freezing point without the occurrence of solidification, i.e., by exercising proper constraint over the experimental variables contributing to nucleation in the melt. The current work of walker1 and Colligan Metal reports undercooling large continuous samples of nickel by imposing appropriate restrictions upon the parameters of solidification. The silver-nickel equilibrium diagram3 reveals the presence of a monotectic reaction at 1435°C. At this temperature the maximum solid solubility of silver in nickel is approximately 3 wt pct, but this solubility decreases with decreasing temperature and the solute is rejected as a silver-rich liquid phase at temperatures below 1435°C. Thus, the 1.0 wt pct solute should be held in solution during undercooling and solidification and subsequently precipitate as a silver-rich liquid phase at grain and subgrain boundaries following solidification during cooling below 1435. This assumes no solute segregation sufficient to cause the monotectic reaction. One would expect this second phase to inhibit grain and subgrain growth by retarding dislocation motion after solidification is complete. The effectiveness of silver addition in growth retardation of high-angle grain boundaries has been demonstrated by Colligan and suprenantS4 The principal [l00] dendrite growth directions in a 2 wt pct Ag-Ni alloy undercooled 53 all radiated from the nucleation site. A similar pure nickel ingot undercooled 59°C exhibited a random orientation of [l00] dendrite directions with respect to the nucleation site. Since undoped nickel ingots do not retain any evidence of the casting or solidification texture and silver-doped ingots do retain this texture, it is reasonable to assume that considerable grain growth has taken place in the pure nickel. These particular experiments were performed in order to reveal the differences, if any, in the features of the crystallographic substructure of undoped undercooled nickel and silver-doped undercooled nickel. 1) EXPERIMENTAL PROCEDURE Data are reported on selected specimens from two massive (approximately 260 g) undercooled ingots of nickel. One ingot consisted of electrolytic nickel and the other of this same material with 1.0 wt pct addition of high-purity silver. Powder patterns were taken of both the as-received and as-solidified materials; in all cases the reflections recorded were attributable to the individual elements nickel and/or silver. Fig. 1 is a. schematic diagram of the apparatus employed for the undercooling experiments. The equipment consists in part of a fused silica crucible for containing the charge. A fused silica tube encloses the system, which is covered by a brass cap to permit partial sealing of the inert atmosphere. This cap contains a hole through which a Pt-Pt 13 pct Rh thermocouple is inserted for temperature measurement. The charge is inductively heated under a purified argon atmosphere.

Jan 1, 1963

By A. Gatti, R. L. Fullman

A very fine dispersion of aluminum oxide is produced by internal oxidation of solid-solution alloy of 0.14 pet A1 in Ag. The particle size of the aluminum oxide is approximntely 50 to 100A in radius. The yield strength of the alloy is increased markedly by internal oxidation. A further increase in strength is produced by cold working the internally oxidized alloy. Recrystallization is retarded by the finely dispessed aluminum oxide particles, so that the strength increase resulting from cold work is retained on annealing at temperatures 14 to about 700°C. MANY workers'-3 in the past have studied various aspects of the internal oxidation of aluminum-silver alloys. This paper is an extension of these studies with emphasis placed on the effect of time and temperature of annealing on the strength of these alloys after oxidation and subsequent cold working. Two general conditions are necessary to internally oxidize an alloy. First, oxygen must diffuse through the base material more rapidly than does the addition; otherwise oxidation will take place as a surface layer. Secondly, the affinity of oxygen for the addition must be greater than for the base material. After internal oxidation of certain alloys takes place, a marked increase in hardness accompanied by higher yield stress and improved creep properties is noted, presumably as a result of the highly dispersed oxide within the base material. Meijering and Druyvesteyn1 also noted that the internally oxidized portion of a partly oxidized alloy failed to recrys-tallize under annealing conditions that led to coinplete recrystallization of the unoxidized part. EXPERIMENTAL-METHODS AND PROCEDURES Few alloys can be made to contain a second phase that is extremely stable at high temperatures. Silver plus aluminum in solid solution was chosen for these internal oxidation studies because of the high rate of oxygen diffusion through silver and the very stable nature of aluminum oxide. Two alloys were vacuum cast. The nominal compositions were: Alloy A—1 pct Al, balance Ag; Alloy B—0.1 pct Al, balance Ag. Chemical analysis, which does not distinguish between aluminum and aluminum oxide, showed the conlposition to be: Alloy A—1.6 pct Al, and Alloy B—0.14 pct Al. The ingots were machined for surface cleaning, swaged and drawn to 0.020-in. diam wire. A sample 20 ft long of the 0.020-in. dianl wire of each composition was annealed 24 hr at 800°C in pure dry hydrogen. Each wire was then cut into two equal pieces. Photomicrographs of the 0.14 pct A1 alloy are shown in Fig. 1, the annealed 0.020-in. wire at the left and the oxidized wire to the right. The oxidation treatment for the first set of data was 1000 hr at 800°C in air. After this treatment the 1 pct A1 proved to be brittle. It is assumed that high alunlinum oxide concentration at the grain boundaries was responsible. The 0.14 pct Al wire remained ductile and all further data were derived using this alloy. One-half of this wire, about 5 ft, plus 5 ft of as-homogenized wire, was then drawn cold to 0.005 in. diam. All tensile tests were conducted with an Instron Engineering Corp. tensile-testing machine, Model TT-B. Unless otherwise indicated, the tests were made at room temperature with a strain rate of 0.1 per min. All metallographic samples were etched with an aqueous solution of 2 pct each of CrO3 and H2SO4 . EXPERIMENTAL RESULTS AND DISCUSSION PARTICLE SIZE DETERMINATION A study was made of the particle size of the aluminum oxide produced in the samples of Ag + 0.14 pct Al, oxidized 1000 hr at 800°C. A cross section of the as-oxidized wire was mounted in bakelite, polished, and etched with an aqueous solution of 2 pct each of CrO3 and H2SO4. The specimen was then thoroughly cleaned by stripping successive coatings made by applying 10 pct nitrocellulose in amyl acetate. The final replica of the cross section was made by applying 2 pct nitrocellulose in amyl acetate. The replica was stripped, transferred to a copper screen, shadow cast with chromium at 10 deg and photographs taken using a Phillips Metallix electron microscope at an accelerating potential of 100 kv. A photograph of an etched sample of the as-oxidized material is shown in Fig. 2. We believe the pits in the photograph are places were A12O3 inclusions were sitting in the matrix. By inspection, it appears that the volume fraction ob-

Jan 1, 1960

By M. C. Fuerstenau, W. F. Cummins

The flotation response of quartz in the presence of calcium chloride and various fatty acids is presented. Flotation is not effected with lauric acid until calcium laurate is precipitated in solution, while flotation is obtained with the 9, 10, and 11-carbon members before precipitation of the calcium carboxylate. The active species responsible for flotation is suggested to be a basic aqueous complex, e.g. Ca(OH) (RCOO) (aq), and a possible mechanism of adsorption is given. Most of the previous work on activation in non-metallic flotation systems has involved the use of high molecular weight collectors, such as oleic acid or alkyl aryl Sulfonate.1-7 In these studies the levels of addition of collector and activator required for flotation were much above the concentrations necessary for precipitation of the metal-collector salt. In fact, Clemmer, Clemmons, Rampacek, Williams, and Stacy1 have stated, "Our experiments on a variety of materials have demonstrated that the metal salts which react with anionic collecting agents, as soaps and alkyl sulfates, to form relatively insoluble compounds may be employed as activating agents provided an optimum quantity is used at a proper pH." On the other hand, Gaudin and chang8 obtained flotation with additions of barium and lauric acid below the level required for barium lautate precipitation.

Jan 1, 1968

By R. C. Earlougher

Based on laboratory tests conducted with the use of fresh core samples as well as a considerable amount of field data obtained from numerous water floods in northeastern Oklahoma, it appears that for any given oil saturation there is a critical maximum velocity above which the oil-recovery efficiency falls off very rapidly. In effect, when a water flood is operated above this critical velocity, the injected water-oil ratio rises extremely fast, thus shortening the economic life of the flood and reducing the ultimate oil recovery. This critical velocity apparently varies considerably with the percentage of oil saturation of the sand, so that in effect the higher the oil saturation at the beginning of a flood the higher the velocity that can be used successfully. In reviewing several of the earlier floods in the Mid-Continent area, it is concluded that most of the failures were due to two things: (I) too low an oil saturation, such as 30 per cent, and (2) too high water-injection rates, Although considerably more field data are necessary to establish definite limits, it would seem that the proper field injection rate for a 330 by 330 or 440 by 440-ft. spacing varies from approximately I bbl. per foot of sand per day where the oil saturation is as low as 30 per cent up to 5 bbl per foot of sand per day when the oil saturation is as high as 45 to 50 per cent, Introduction With secondary recovery by water-flooding receiving more and more attention throughout the industry, a greater working knowledge of multiphase flow under field conditions becomes more and more necessary A great deal of research has been carried on in highly idealized laboratory conditions, from which certain trends have been indicated, but with few exceptions no direct application to field use has been reported. widely varying conclusions have been drawn from the mass of idealized laboratory experiments and often this divergence apparently was due to the neglect of connate or interstitial water. Since interstitial water is such an important factor in water-flooding operations, it then follows that any laboratory flooding experiment must necessarily take it into account; and since it is difficult to set up laboratory models to allow for interstitial water, the next best procedure is to use fresh core samples for such tests. Even this procedure has its difficulties, inasmuch as it is possible to run only one flooding test on each sample, as each sample differs somewhat in character from all other samples. However, this disadvantage can be overcome to a large degree by the use of an extremely large number of samples. The next question that arises is: "IS it possible to get uncontaminated core samples having a true oil and water saturation like that existing in the reservoir?" If the sand under consideration is still in the primary stage of production, with a normal or relatively high amount of gas still in solution in the oil, probably it is not possible to get a nonflushed core. On the other

Jan 1, 1943

By R. C. Earlougher

Based on laboratory tests conducted with the use of fresh core samples as well as a considerable amount of field data obtained from numerous water floods in northeastern Oklahoma, it appears that for any given oil saturation there is a critical maximum velocity above which the oil-recovery efficiency falls off very rapidly. In effect, when a water flood is operated above this critical velocity, the injected water-oil ratio rises extremely fast, thus shortening the economic life of the flood and reducing the ultimate oil recovery. This critical velocity apparently varies considerably with the percentage of oil saturation of the sand, so that in effect the higher the oil saturation at the beginning of a flood the higher the velocity that can be used successfully. In reviewing several of the earlier floods in the Mid-Continent area, it is concluded that most of the failures were due to two things: (I) too low an oil saturation, such as 30 per cent, and (2) too high water-injection rates, Although considerably more field data are necessary to establish definite limits, it would seem that the proper field injection rate for a 330 by 330 or 440 by 440-ft. spacing varies from approximately I bbl. per foot of sand per day where the oil saturation is as low as 30 per cent up to 5 bbl per foot of sand per day when the oil saturation is as high as 45 to 50 per cent, Introduction With secondary recovery by water-flooding receiving more and more attention throughout the industry, a greater working knowledge of multiphase flow under field conditions becomes more and more necessary A great deal of research has been carried on in highly idealized laboratory conditions, from which certain trends have been indicated, but with few exceptions no direct application to field use has been reported. widely varying conclusions have been drawn from the mass of idealized laboratory experiments and often this divergence apparently was due to the neglect of connate or interstitial water. Since interstitial water is such an important factor in water-flooding operations, it then follows that any laboratory flooding experiment must necessarily take it into account; and since it is difficult to set up laboratory models to allow for interstitial water, the next best procedure is to use fresh core samples for such tests. Even this procedure has its difficulties, inasmuch as it is possible to run only one flooding test on each sample, as each sample differs somewhat in character from all other samples. However, this disadvantage can be overcome to a large degree by the use of an extremely large number of samples. The next question that arises is: "IS it possible to get uncontaminated core samples having a true oil and water saturation like that existing in the reservoir?" If the sand under consideration is still in the primary stage of production, with a normal or relatively high amount of gas still in solution in the oil, probably it is not possible to get a nonflushed core. On the other

Jan 1, 1943

By P. S. Rudman

Laves phases, AB2, are considered as Izerrzisub-stitutional solutions m1hich are defined by a one-for-truo replacement scheme. Atomic-size tnisfit is considered in terms of deviations of the ratio 2V°b/V°A from unity, where v° = atomic volume. A simple elastic model has been used to calculated deviations from "Vegard&apos;s law of atomic vol-umes". Comparison has been made between calculated and observed atomic-volume deviations fov 222 Laves phases. Agreement is generally very good although there ave some few exceptions which appear to be excusable in terms of electronic changes that ore beyond the scope of the present model. We can consider the formation of a binary sub-stitutional solution A-B from an A solvent as one-for-one replacements of A atoms by B atoms. As the atomic-size ratio deviates from unity, the solution becomes thermodynamically less stable and hence more restricted because of atomic-misfit strain energy. In accordance with our previously presented conclusion1 that the atomic volume, v, is in general the most appropriate measure of atomic size, the ideal size ratio for a binary sub-stitutional solution is vg/vA = 1. The Laves phases have been described by Berry and Raynor2 in terms of various stacking sequences of hexagonal layers of B atoms for the three structures MgZn2(C14), MgCu2(C15), and MgNi2(C36). To form the Laves phase of ideal composition AB, we start with complete hexagonal layers of B atoms in the appropriate stacking sequence and we remove, according to an appropriate scheme for each structure, two out of every four B atoms and replace the two removed atoms by one A atom. We thus might expect to find that the ideal size ratio for the Laves phases is 2v/B/ VA= 1. From this point of view, then, we call Laves phases hemi-substitutional solutions since we employ one-for-two replacements. By analogy with substitutional solutions we can expect for Laves phases that as the ratio 2VB/Va deviates from unity the phase occurrence will be more restricted. Laves3 has plotted the distribution of Laves phases as a function of the radius ratio, ?A/rB, and found that, while the distribution extended from 1.05 < rA/B < 1.50, the

Jan 1, 1965

What is a conflict, as it is understood by men of the extractive industries? And what are the circumstances out of which these conflicts arise? A start can be made with the notion of economic conflict, which can be defined as rivalry over the use of economic resources. Such rivalry is a central part of all economizing activity. It is present within the individual, within the family, and within the business firm. In each of these units there are multiple goals competing for use of a limited income. And economic rivalry is present among individuals and firms who are competing with one another for use of the limited quantity of economic resources available to us as a society.

Jan 7, 1961

By H. M. Fisher, R. E. Snow, S. C. Sun

SEVERAL constructive and fundamental studies have been made in the analysis of data obtained from experiments carried on with batch ball and rod mills. The operating characteristics of ball milling in small continuous circuits have also been appraised. It is from these analyses that some of the theories of comminution have been developed. Relatively few studies of continuous rod milling have added significantly to the fundamental concepts, because seldom have they yielded sufficiently consistent results. Perhaps they have been too limited in their scope. Careful control of the variables in batch grinding is simple compared with that encountered in a continuous operation. This factor alone has discouraged many investigators. Occasionally results of systematic changes made in industrial rod mill circuits have been published, but usually the data are sketchy and are restricted because of the unwieldiness of the equipment used. The work, in general, has not been comprehensive; nevertheless it has provided empirical relationships that have bridged the gap between postulate and practice so that by proper manipulation of formulae, a mill designer can anticipate mill size and power requirements.14 Although operating variables of a small continuous mill are not so easy to control as with the batch mill, with present day devices, and with careful experimental work, consistent results can be obtained. Nearly four years ago, in the Process Laboratory, Allis-Chalmers Mfg. Co. began a systematic study of the effects of several variables upon the performance of the pilot rod mill. A mill was built in the laboratory to provide the versatility required for the proposed study. It was constructed in sections so that it could be operated, with a few modifications, as a rod mill 30 in. x 8 ft or 30 in. x 4 ft. The discharge end of the shell was flanged so that either an end peripheral discharge or an overflow discharge could be installed. Thus the performance of at least four types of mills could be studied merely by changing the type of discharge or the length of the mill shell. The grinding experiments were designed so that a study could be made of the way in which the mill speed, feed rate, and pulp density influenced the performance of both overflow and end peripheral discharge rod mills. Four sets of experimental data were collected from the four mill arrangements. The mill in each set of experiments was fed at four rates of feed depending on the length of the mill, at four pulp densities, and at five percentages of critical speed. Electrical and mechanical controls were in- stalled to regulate all these independent variables, and auxiliary devices were used to verify the precision of the controls at each point. The dependent variables used to quantify the experiments were the reduction ratio and the hew surface area produced as calculated from sieve analyses. These were incorporated with the energy factor by the calculation of both the new surface produced per unit of energy and the Bond work index.&apos; Rod wear, as a dependent variable, was not studied because of the short period of operation for each run. Exclusive of repeat runs, each set of experiments yielded 80 products, and the total study at least 320 products, all of which were quantified. With the operating information collected, these data presented a bewildering accumulation. Statistical analysis has been invaluable in unraveling the confusion and in presenting a means of establishing the nature and the magnitude of the significant variables. Data presented in this paper are those from the 30 in. x 4 ft end peripheral discharge rod mill, Fig. 1, when limestone was ground at feed rates of 1000, 2000, 4000, and 5000 lb per hr, at pulp densities of 50, 60, 70, and 80 pct solids, and at mill speeds of 50, 60, 70, 80, and 90 pct of the critical speed. These 80 tests have all been run at least twice, and occasionally a third time, to prove that the data obtained were reproducible. The techniques of operation and the methods of quantification of results are described in the following pages and the results analyzed statistically to show the significant variables. The variables are plotted to show the relationships that exist. A massive dolomitic limestone from Waukesha Lime and Stone Co. was used for feed during these experiments because of its availability and its tex-tural uniformity. This limestone analyzed 28.7 pct CaO, 21.0 pct MgO, 6.0 pct SiO2, 0.4 pct A1²O³, and 0.3 pct Fe²O³ and had a loss on ignition of 44.1 pct. It had a rod mill grindability at 14 mesh of 9.6 grams per revolution from which a work index of 13.9 was calculated. The ball mill grindability at

Jan 1, 1955

By D. B. RUSHJIORE

(New York -Meeting, February, 1912.) TORCHES were used by the early Romans for mine-lighting, and these were followed by open lamps or earthen jars filled with tallow or oil, and later by candles. In early coal-mining, explosive gases seldom occurred, and, if they were encountered, the danger of explosion was materially diminished by the absence of any ventilating-system and the consequent insufficient circulation of air to form with the methane an explosive mixture. As the art advanced, the danger of fire-damp became more apparent, and methods for testing the air were resorted to as early as in the fifteenth century. The method of testing consisted in lowering a clog in a, basket down the shaft. As soon as he encountered fire-damp he would commence to howl, after which he was withdrawn, and a leafy bush was fastened to the end of the rope and run rapidly up and clown the shaft. This so disturbed the accumulation of gas as to cause it to rise out of the shaft. Later this odd method of testing was improved upon through the discovery that a light inserted in a body of fire-dam p would produce a blue flame. Candles were used for this purpose, and, when fire-damp was thus discovered, brushing or some other primitive method of fanning was resorted to for driving out the gas. In some instances the gas was burned away, regardless of the danger thereby incurred. A man, wearing a well-moistened coat and a mask with glass spectacles, descended in the mine a few hours before each shift. With a long stick, to which was fastened a burning torch or candle, lie would crawl on the floor with the stick so raised that the light would sweep the roof and ignite the gas which it encountered. In this position the flame of the explosion would pass over him, after which he would retreat from the gases resulting from the combustion. The occurrence of serious accidents resulted in

Jul 1, 1912

By B. J. Scheiner, A. G. Smelley

The Bureau of Mines, US Department of the Interior, is conducting research on a dewatering technique for fine particles generated during the mineral beneficiation process that will recover a portion of the water now being lost using conventional waste disposal methods and significantly reduce the time required for land reclamation. The technique utilizes a flocculant, polyethylene oxide (PEO), that forms strong stable flocs that can be dewatered rapidly on static and/or rotary screens. Infield tests, phosphate clay waste has been dewatered from a nominal 2.5% solids to greater than 20% solids. In other field tests, coal-clay waste has been dewatered from a nominal 3% solids to greater than 55% solids. In addition, small-scale continuous tests have shown that bentonitic clays can be dewatered from 12% solids to 40% solids.

Jan 1, 1985

By J. C. Williams, M. J. Blackburn

MANY aspects of the formation of the metastable w phase in titanium-transition metal alloys have been described in several recent papers.1-4 These papers have reviewed earlier work on the w phase and have further defined most of the important features related to the formation of this phase, e.g-., its crystal structure, composition, and morphology. There are, however, several important points regarding formation of the w phase in titanium alloys which have been described in less detail. Two of these are the relationship between lattice misfit and w phase morphology and the influence of lattice misfit on the mode of formation of the equilibrium a phase. In this communi- cation we will present transmission electron microscopy results relevant to these two points. The alloys used in this study were prepared by non-consumable electrode arc melting, each 30-g button being remelted a minimum of twelve times. The alloy compositions we have studied are listed in Table I. Thin foils were prepared using standard techniques described elsewhere. Two distinct c&apos; phase morphologies have been reported in earlier papers. The phase is ellipsoidal in the Ti-Mo3 and Ti-Nbl system and cubical in the Ti-V3 system. Results of the present study show that the w phase is also cubical in Ti-Mn, Ti-Fe, and Ti-Cr alloys as illustrated in Fig. l(b) to (d). Fig. l(a) shows the ellipsoidal morphology in Ti-MO3 for comparison purposes. It was suggested in an earlier paper3 that the w phase morphology may be controlled by the lat-

Jan 1, 1970

By A. H. Hand

When considering the question of future demand for crude petroleum in California, one must first decide whether it is to be approached in the light of the definition of "demand" when used in economics; i.e., "The quantity of any commodity required or sought in the market," or in the light of markets developed to dispose of total supply. Therefore, is the California demand of future years to be predicated on a continuation of supplying markets developed following the surplus production commencing in 1922, or predicated on supplying what would be termed economic markets ? If the latter, what are economic markets ? Obviously, the Pacific Coast States and Canada, Alaska, Hawaii and probably the Pacific side of Central and South America, can be considered as normal markets for California petroleum products. While there have been small quantities of gasoline shipped into the PacSc Coast from East Texas, transportation costs, plus import taxes in the case of foreign oil, are a sufficient barrier to justify considering that these markets will be retained. But how about our participation in Atlantic and Pacific foreign and intercoastal markets? During the five years preceding 1931 California shipped substantial quantities of gasoline to the United Kingdom and to France, Germany and Italy. During recent years our business in European markets has been restricted to occasional shipments of gasoline and Kettleman crude. This loss of business is occasioned by the development of production in the Mid-Continent, principally East Texas, and in Iraq, Rumania, Venezuela and other closer producing areas, which makes it impossible at the prevailing crude-oil prices for California to be competitive in supplying any substantial portion of these markets. It is therefore apparent that under a stabilized price structure that will return the California producer a reasonable price for his oil, future Atlantic foreign -business will be restricted to occasional spot cargo sales. As to Pacific foreign shipments which, in addition to Central and South America, consist principally of shipments to Japan, China, Australia and New Zealand: A considerable portion of the business we had with Australia and New Zealand until four or five years ago is now being

Jan 1, 1937

By W. W. Wen, S. C. Sun

The objective of this investigation was to study the electrokinetic behavior of oxidized coals to indicate the feasibility of separating oxidized coals from ash materials and pyrite by an amine flotation process. The effects of soluble inorganic electrolyte products from coal oxidation were also examined. The electro-kinetic behavior of coals of different rank and degree of oxidation were studied by an electro-phoreses technique. Generally, increasing the oxidation increases the negative value of the zeta-potential and decreases the isoelectric point (IEP). Flotation results indicate that the flotation recovery increases with decreasing pH values, and that with ferrous sulfate at pH 6.5 the flotation recovery is optimum while the pyrite is depressed. Comparing the flotation results with the electokinetic results verified that in the presence of ferrous sulfate, the maximum hydro-phobicity of oxidized coal with dodecylamine and frother is near its IEP, which is around pH 6.5 to 7.0.

Jan 1, 1978