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By Arnulf Muan, Klaus Schwerdtfeger

Equilibrium ratios C02/C0 of a gas phase coexisting with selected phase assemblages of the system Fe-Mn-0 have been determined in the temperature range 1000" to 1300°C. The oxygen pressure for the "hfnO" +hfn30, equilibrium and for the "(Fe,hTn)O" + (Fe,Mnh 0* equilibrium at high manganese contents has been determined by electromotive force measurements using stabilized zirconia as a solid electrolyte. The notstoichometry 01' "hTnO" and of "(Fe, iM1z)O" solid solutions has been determined by ther-mog-/avi?netry and by wet-chemical analysis. The data obtained are used to derive activity-composition relations in "(Fe,hfn)O" and (Fe,Mn),O4 solid solutions. WUSTITE "FeO" and manganosite "MnO" form a continuous series of solid solution at high temperatures,' and so do magnetite Fe304 and the high-temperature, cubic modification of Mn304 (Ref. 2) (high hausmannite, -1170). The oxides "FeO" and "MnO" are cation-deficient phases.495 The nonstoi-chiometry of "(Fe,Mn)O" solid solutions has been studied by Engell and ~ohl' at two selected C02/C0 ratios at 1250°C. The two oxide end members of the spinel solid solution, FesO4 and Mn,04, however, are known to be close to stoichiometric under the experimental conditions used in the present investigation.''' The oxygen pressures of "(Fe,Mn)07' solid solutions in equilibrium with iron have been determined by Schenck and coworkers,8 by Foster and welch," and by ~n~e1l.l' The two former groups equilibrated the condensed phases in C02-CO atmospheres of lmown compositions, whereas Engell" used a galvanic cell with stabilized zirconia as a solid electrolyte. The results of these investigators are not in good agreement. Activities of FeO in manganowiistite as calculated from the results of Foster and Welch show ideal behavior, those of Engell yield a pronounced positive deviation, and those of Schenck et 01. show a moderate positive deviation from ideality. In the present work oxygen pressures for the iron + manganowiistite and manganowustite + spinel equilibria and the nonstoichiometry of manganowiistites have been measured. The data were used to calculate activities in the manganowiistite and spinel solid solutions. EXPERIMENTAL METHODS The COz/CO ratios at which manganowustite and iron are in equilibrium were determined by thermo-gravimetric and quenching methods. Experimental details are described in a previous publication.'2 In the thermogravimetric technique, incipient reduction of manganowiistite pellets to metallic iron was observed as a break in the weight vs log COZ/CO curve. In the quenching technique, manganowiistite samples were partially reduced to metallic iron, or the metallic iron of manganowustite + metallic iron mixtures was partially oxidized to manganowustite, in atmospheres of constant C02/CO ratios. After quenching the composition of the oxide phase was determined by X-ray lattice parameter measurements and comparison with a standard curve obtained from oxide solid solutions of known compositions. The nonstoichiometry of "MnO" and "(Fe,Mn)07' solid solutions was determined by chemical analysis of samples equilibrated in C02-CO atmospheres and quenched to room temperature, as well as thermo-gravimetrically by reducing (Fe,Mn),04 or Mn304 to manganowiistite or manganosite. The equilibrium between manganowiistite and (Fe,Mn),04 was measured thermogravimetrically by reducing (Fe,Mn),04 solid solutions having composition in the range of %„ l(NFe +NM) from 0 to 0.63. No experiments could be performed with this technique at higher manganese contents, because the equilibrium C02/C0 ratios are too large for accurate control. An additional difficulty arises at the higher manganese contents due to the strong increase in oxygen content of the manganowustite phase with increasing log Py near the manganowiistite-spinel boundary. Consequently a sharp break in the weight loss vs log C02/CO curve cannot be observed at the phase boundary. At high manganese contents of the manganowiistite, e.g., (NMn/(NF~ + NMn) > 0.9, electromotive force measurements with stabilized zirconia as a solid electrolyte were made to determine the equilibrium oxygen partial pressure. Experimental details are described in a previous paper.* Mixtures of "(Fe,Mn)O" and (Fe,Mn),04 were pressed to pellets, and the oxygen pressure of the equilibrated samples was compared to that of Ni + NiO mixtures in the cell The composition of the manganowiistite in the equilibrated two-phase mixture was determined by lattice parameter measurements and comparison with known standards. The oxygen pressure for the Ni + NiO equilibrium was taken from available data.l3~l4 No reliable results were obtained with the electromotive force technique on iron-rich oxides. The electromotive force drifted strongly with time in this composition range. An additional difficulty arises from the partial de-

Jan 1, 1968

By Mark J. Klein

The behavior of nitrogen in Cr-0.12 at. pct Y was studied in specimens of varying interstitial concentration and thermal history. It was found that soluble nitrogen can be introduced into this alloy by increasing the concentrations of either oxygen or nitrogen. For low nitrogen concentrations the nitrogen in solution is low relative to that in unalloyed chromium. However, the nitrogen in solution increases with increasing nitrogen concentration, approaching that in unalloyed chromium. When the alloy is supersaturated with nitrogen, the nitrogen precipitates readily from solution as a chromium nitride. The stress -induced relaxation of nitrogen is influenced by internal oxidation or internal nitrification of this alloy. THE addition of small concentrations of reactive elements such as yttrium have been found to enhance the low-temperature ductility of chromium.&apos; However, the mechanism by which the ductility is increased is not known. It has been suggested that this effect is caused by a drastic reduction in the concentration of nitrogen retained in solution and therefore a decrease in the number of dislocations locked by nitrogen, a factor that has been associated with an increase in ductility.1,2 However, a change in the type of interstitial precipitate induced by yttrium could also contribute to enhanced ductility of the alloy, since chromium nitride precipitates appear to be embrittling.&apos; In this regard, it has been shown that yttrium scavenges nitrogen in chromium to form YN,4 thus reducing the embrittling chromium nitride phase. However, the change in nitrogen solubility induced by yttrium and the partition of nitrogen between chromium and yttrium nitrides are not known. The object of this investigation is to study the effect of yttrium on the behavior of nitrogen in chromium to obtain information relevant to the mechanism by which scavengers enhance the ductility of chromium. EXPERIMENTAL PROCEDURES The experimental procedures used in this investigation have been described in detail elsewhere.5,6 Wires of Cr-0.12 at. pct Y, 15 cm in length and 1 mm in diam, were drawn from rods 0.6 cm in diam supplied by the General Electric Co. The grain size of the wires after recrystallization at 1150°C was somewhat nonuniform, varying from 0.006 to 0.06 mm in diam. The interstitial analysis for the wires in ppm by weight was about 160 0, 80 N, 12 C, and <2 H. Heat treatments were carried out after encapsulation of the specimens in quartz tubes containing argon. Changes in interstitial concentrations, or interstitial "loading" as it is termed in this study, were generally accomplished by annealing in oxygen, ammonia or methane at 1150°C. The internal friction was measured using a conventional torsional pendulum enclosed in an evacuated chamber. Electrical-resistivity measurements were made at liquid-nitrogen temperature.

Jan 1, 1967

By J. P. Hirth, G. M. Pound

The flux of evaporation J from {loo) , {111), and (110) planes of silver single crystals and from poly crystalline specimens was measured at 744°C under a high vacuum using a time average weight loss method. The evaporation coefficient a was computed from the measured flux and vapor pressure data through the relationship J = aPe/21rmkT. The evaporation coefficients for the close packed planes and the poly crystalline specimens were found to be about 0.4 providing tentative confirmation of the theoretical limiting law for evaporation of metal crystals, a = 73(P/Pe) + % . The (110) planes faceted to form (111) planes, resulting in a greater evaporating area and larger a . The evaporation morphology of the plane surfaces and the surfaces of spherical single crystals is described in some detail. RECENTLY a detailed theoretical analysis of the mechanism and kinetics of metal crystal evaporation was made.1&apos;2 A mechanism for vaporization involving the recession of monatomic ledges across a metal surface was deduced, and evaporation rate equations were derived by considering the dynamics of these ledges. In most metals, the process of evaporation is one of dissociation of atoms from ledges, surface diffusion, and desorption. The gross vaporization rate is controlled by the surface diffusion and desorption rates. It was shown that the monatomic ledges, under the action of surface diffusion gradients, tend to assume a terminal velocity and spacing. Further, it was shown that crystal edges and grain boundaries are a ready source for monatomic ledges. In the case of evaporation of large, perfect crystals with clean, low-index surfaces, the kinetic treatment1 leads to a limiting law for crystal evaporation: where J is the gross flux of vaporization, a is the evaporation coefficient, Pe the equilibrium vapor pressure, m the atomic mass, k Boltzmann&apos;s constant, T the absolute temperature, and P the actual pressure of vapor over the crystal surface. Imperfections such as grain boundaries, pores, cracks, and macroscopic steps should have the effect of causing positive departures from this limiting law. Such an imperfection is a source for monatomic ledges, which, near their origin, are closely spaced and thus give rise to higher evaporation rates there. However, under many experimental conditions,&apos; this effect should be negligible due to the relatively low concentration of imperfections. In general, a more important cause of positive departure should be screw dislocations, and the effect of these has been considered in some detai1.2,3 Monatomic ledges emanate from points where the surface is intersected by a dislocation with a screw component normal to the surface. The dynamics of ledges arising from a screw dislocation are similar to those of ledges arising from a crystal edge. There is a perturbed region near the origin where the monatomic ledges are, under certain experimental conditions, closely spaced and the

Jan 1, 1960

By A. G. Roach

THIS paper deals with a plant built under joint agreement between the Canadian and United States Governments to supply the strategic mineral, corundum, at a time when African production was dwindling and war demands still increasing. The operation began in September 1944, retreating the tailings from a former mill by gravity methods, and is still in production (Sept. 1946). In 1942, when it became apparent that South African production would be insufficient to meet mounting wartime requirements of corundum, a survey was made of Canadian sources of the mineral, at the request of the Foreign Economic Administration of the U. S. Government. The investigation1 indicated that the quickest and cheapest supply would be obtained by reworking the tailings deposit at Craigmont, Ontario. Sampling of the dump by Canadian Government engineers revealed that 125,000 tons of tailings, averaging 2.96 pct corundum, was available for retreatment. Ore-dressing tests on representative samples of the deposit were conducted by the writer in the laboratories of the Industrial Minerals Section of the Department of Mines and Resources at Ottawa; and gravity concentration on tables was indicated as the most suitable method of treatment. Decision to proceed with the project was deferred until May 9, construction was begun on May 18, and tune-up operation of the plant begun on Sept. 15, 1944. CORUNDUM-ITS PROPERTIES AND USES Corundum is an oxide of aluminum having the formula A1203. Its outstanding characteristic is its great hardness; 9 in the Mohs scale. In this respect it is second only to the diamond. It usually occurs in barrel-shaped crystals in nepheline syenites and other feldspathic rocks deficient in silica. It has a specific gravity of 3.95 to 4.1 and is insoluble and infusible. In color it ranges from white, through red and green, to black. Ruby and sapphire are gem varieties of corundum. Corundum is supplied to industry as closely graded grain.2 The coarser products (10 to 24-mesh) are used largely for snagging wheels in the steel-castings industry, while the finer grades (from 70-mesh down to flours) find a wide application in the polishing of lenses and for other uses in the optical trade. All sizes of corundum grain are in close competition with synthetic abrasives such as carborundum and alundum. In some fields of application the artificial product is superior to the natural grain but not in all. The shape of the particle and its behavior under conditions of actual use determine its sphere of employment. The United States is the largest consumer of corundum, annual consumption in peacetime approaching 3000 tons; during the war this figure was roughly doubled. During the years 1902 to 1913, the bulk

Jan 1, 1946

By T. H. Alden, H. W. Schadler

The strain rate dependence of the flow stress of the eutectoid Zn-Al alloy has been determined as a function of mechanical processing, microstructure, and temperature. The best superplastic properties result from the ultrafine, equiaxed structure produced by solution treatment and isothermal transformation at 0°C. Lamellar structures produced by isothermal transformation and coarse equiaxed structures produced by annealing also exhibit strain rate sensitivity in excess of 0.5, but at higher stresses and lower strain rates than the finest structure. Solution treatment and isothermal transformation eliminate the effect of prior processing history. Small composition variations in the binary alloy do not influence the mechanical properties. Below the eutectoid transformation temperature (.275C) increasing temperature lowers the flow stress at all strain rates. The data do not favor any of the present proposals for the mechanism of superplastic flow. ALLOYS of zinc and aluminum, near the eutectoid composition, have been investigated for: 1) the flow stress-strain rate and elongation behavior,1, 2) the transformation kinetics,3 and 3) structure,3"5 but the structure sensitivity of the mechanical properties is poorly understood. Using a near eutectoid alloy water-quenched from 380°C, Backofen et aL2 estab- high and increases with increasing strain rate. They found a correlation between strain rate sensitivity and tensile elongation as expected from the increased resistance to necking that a high strain rate sensitivity provides.296 The large elongation at high strain rates is attractive for metal forming. Since most other superplastic alloys7-l3 do not show high strain rate sensitivity at such a high strain rate (for the exception see Ref. 12) there is the possibility of a unique deformation mechanism for this alloy. The sensitivity of the mechanical properties of the eutectoid alloy to thermal history1 suggests a structure sensitivity that has not been demonstrated. Gar-wood and Hopkins3 identified a lamellar product for material transformed between 200" and 260°C. The size of the lamellae decreased with decreasing temperature. They also demonstrated that an unresolved transformation product formed below 200°C. A granular two-phase material was resolved for specimens quenched to below 150°C by Mitbauer and sauerwald4 who observed coarsening of the structure after annealing. The role of grain boundaries in superplastic deformation is suggested by the strong effect of grain refinement in encouraging this phenomenon at high strain rateS7-11, 13 and is emphasized in several proposals about rnechanism7, 8, 12 and in a theory14 of high-temperature deformation. Alden8 showed metallographic evidence that grain boundary sliding is occurring extensively at strain rates where m is large but less at high strain rates where normal plasticity is observed. Holt and Backofen10 have shown that sliding also oc-

Jan 1, 1969

By C. R. Holmgren

A large consolidated sand core was used in this investigation. Four groups of experiments including gas drives, water drives, and water drives combined with gas injection, were made. The results of the gas-drive experiments indicate that greater ultimate recovery may be obtained by higher pressure gradients. However, other considerations challenge the absolute veracity of this conclusion. Results indicate that with connate water present and a low pressure gradient during a gas drive, less gas is required to produce a given amount of oil. The saturation gradient determined during a gas drive is presented. Results of the water-drive experiments indicate that the recovery of oil is not a function of either gradient Or input rate. The presence of initial gas saturation resulted in a slightly lower final oil saturation. Injection of sufficient gas to maintain the initial gas saturation during a water drive resulted in lower final oil saturation. Introduction With the demand for petroleum products reaching an all-time record high and the location and exploitation of new reserves becoming more difficult and expensive, the oil industry must look to more thorough and efficient methods of producing the petroleum already located. Much of the previous work along these lines is exploratory and suggests a more complete investigation. For example, a great amount of laboratory work has been done on flooding sands initially saturated roo pct with oil. Since sands saturated roo pct with oil rarely, if ever, exist in nature, and because the water content is a vital factor in the ultimate recovery from the sand, laboratory investigations on cores without water must be supplemented by comparable work on cores with water present.1&apos;2 Other investigators have done a considerable amount of laboratory work using gas and water drives.3 Krutter and Day4 have reported results of investigations using cores saturated IOO pct with oil and have concluded that " the ultimate recovery obtained, using air drive, from a completely oil-saturated core depends on the pressure gradients used. The higher the pressure gradient, the greater will be the recovery until a certain Pressure range is reached above which the reward of increased recovery is much smaller for similar increments in pressure." Yuster and Day6 conclude that less gas and less time are required to produce a given quantity of oil at high pressure gradients than at low pressure gradients; they also conclude that an increase in the viscosity of the oil requires a proportionate increase in the gas needed for recovery. Their results indicate that the gas required to produce a given quantity of oil is greatly reduced by the presence of connate water. R. C. Earlougher2 concluded, based on results of water-flooding a large number of

Jan 1, 1949

By Frank G. Miller

The lower cost of producing oil from naturally flowing wells compared with pro-luction costs accruing from artificial lifting methods has stimulated much research, rith the joint purpose of extending the natural flowing life of wells and of increas-ng the productivity of small wells. The iboratory investigation described herein was made to determine the effect of a lotted liner on the pressure gradient in the icinity of the wall of a flowing well. Flow estrictions caused by the liner induce nergy losses between the oil-bearing for-lation and the inside of the liner, which lay be reduced by improved liner design, nd thereby the flow capacity of wells may e increased. These losses have been evalu-ted for rectangular slots of different sizes, nd means are suggested for reducing them. The dearth of information concerning the ature of the flow of fluids from uncon-slidated sands through small openings in he walls of. pipes—as represented by the ow of oil from an oil sand into a slotted ner—is acknowledged. Although the bene-ts to be realized by operators through the se of optimum liners is just beginning to e recognized generally, Coberlyl in 1937 ointed out that the functioning of screen is is an important factor in the pro-uction of oil. From his study on the :lection of size of oil strings for wells in California, Parks2 concluded, in part, that the perforated section of the oil string deserves continued study, especially with respect to the selection of perforations. The growing use of gravel packing resulting from certain research findings lends even more significance to the problem of selecting optimum liners, as the application of these methods usually requires slotted liners or other kinds of perforated liners. The present study was made to obtain further information for the guidance of engineers and operators in selecting slotted liners and to develop a laboratory method that may be used in analyzing possible pressure conditions surrounding most types of perforated casings used in producing oil wells, so that the present inadequate fund of knowledge on this important subject may be expanded. Discussion of ProbleM At the beginning of the investigation the following assumptions were made regarding bottom-hole conditions of a producing oil well and the oil-sand reservoir it penetrates: (I) Conditions of steady-state flow exist, (&apos;) a a homogeneous liquid is being produced) (3) no contaminating material (such as drilling fluid) is present between the liner and the face of the oil-bearing sand, (4) the well is vertical and completely penetrates a horizontal sand stratum of uniform thickness occurring between two impermeable strata, and (5) the flow is wholly viscous. If the foregoing assumptions are made, with the added requirements that the sand

Jan 1, 1941

By Frank G. Miller

The lower cost of producing oil from naturally flowing wells compared with pro-luction costs accruing from artificial lifting methods has stimulated much research, rith the joint purpose of extending the natural flowing life of wells and of increas-ng the productivity of small wells. The iboratory investigation described herein was made to determine the effect of a lotted liner on the pressure gradient in the icinity of the wall of a flowing well. Flow estrictions caused by the liner induce nergy losses between the oil-bearing for-lation and the inside of the liner, which lay be reduced by improved liner design, nd thereby the flow capacity of wells may e increased. These losses have been evalu-ted for rectangular slots of different sizes, nd means are suggested for reducing them. The dearth of information concerning the ature of the flow of fluids from uncon-slidated sands through small openings in he walls of. pipes—as represented by the ow of oil from an oil sand into a slotted ner—is acknowledged. Although the bene-ts to be realized by operators through the se of optimum liners is just beginning to e recognized generally, Coberlyl in 1937 ointed out that the functioning of screen is is an important factor in the pro-uction of oil. From his study on the :lection of size of oil strings for wells in California, Parks2 concluded, in part, that the perforated section of the oil string deserves continued study, especially with respect to the selection of perforations. The growing use of gravel packing resulting from certain research findings lends even more significance to the problem of selecting optimum liners, as the application of these methods usually requires slotted liners or other kinds of perforated liners. The present study was made to obtain further information for the guidance of engineers and operators in selecting slotted liners and to develop a laboratory method that may be used in analyzing possible pressure conditions surrounding most types of perforated casings used in producing oil wells, so that the present inadequate fund of knowledge on this important subject may be expanded. Discussion of ProbleM At the beginning of the investigation the following assumptions were made regarding bottom-hole conditions of a producing oil well and the oil-sand reservoir it penetrates: (I) Conditions of steady-state flow exist, (&apos;) a a homogeneous liquid is being produced) (3) no contaminating material (such as drilling fluid) is present between the liner and the face of the oil-bearing sand, (4) the well is vertical and completely penetrates a horizontal sand stratum of uniform thickness occurring between two impermeable strata, and (5) the flow is wholly viscous. If the foregoing assumptions are made, with the added requirements that the sand

Jan 1, 1941

By E. M. MacKevett

The only source of uranium ore in Alaska that has been mined commercially is the Ross-Adams deposit, a gently inclined, fusiform orebody in alkali granite in which uranothorite and uranoan thoria-nit? ale the chief ore minerals. In mode of occurrence, apparent genetic association with the granite, and to a lesser extent in mineralogy, this type of deposit is uncommon. The mine is in the southern part of Prince of Wales Island (Fig. 1) at an altitude of about 950 ft on the southeast flank of Bokan Mountain. A steep unpaved road 1 3/4 miles long leads to the dock on the West Arm of Kendrick Bay, which can be reached by boat or seaplane from Ketchikan, some 35 miles to the northeast. The southern section of Prince of Wales Island is covered by dense forests interspersed with swampy tracts of muskeg. Most of the higher peaks support only sparse vegetation, and in areas underlain by alkali granite bare rocky slopes prevail to as low as 800 ft. Numerous fiord-like embayments penetrate this part of the island, and their shorelines provide near-continuous rock exposures. Rainfall is heavy, about 150 in. annually. Throughout the year the climate is relatively mild. History and Production: In May 1955 two members of a Ketchikan prospecting group, Don Ross and his wife, found the deposit while working with an airborne geiger counter. Later they confirmed their discovery by ground investigations. During the summer Climax Molybdenum acquired controlling interest in the property and started exploratory diamond drilling, resuming the drilling on a larger scale in the summer and fall of 1956. Climax began mining in July 1957, shipping the ore by barge and train to the Dawn Mining Co. mill at Ford, Wash. The open pit workings, about 370 ft long, between 25 and 75 ft wide. and 25 ft deep (shown in Fig. 2) were shut down in October 1957. As of September 1958 the pit was still inactive, although a small tonnage of known reserves remains in the southern part. The operators believe the 15,000 tons of uranium ore already produced will average 0.80 pct. GEOLOGY The Ross-Adams mine is within a small stock or boss of alkali granite, about 1000 ft from the southeast margin of the granite (Fig. 3). The area around the boss is underlain chiefly by plutonic rocks of intermediate composition and by metamorphosed sedimentary and volcanic rocks. The oldest rocks in the area probably are the metamorphosed volcanic rocks that are well exposed adjacent to the South Arm of Moira Sound. They are considered by Buddington and Chapin1 to be of Devonian age. These light gray to dark gray rocks mainly represent a layered volcanic sequence. They are commonly porphyritic with plagioclase pheno-crysts in an altered, fine-grained groundmass. The

Jan 1, 1960

By James E. Berryman

A method is presented for calculating the pressure depletion performance of a gas-condensate reservoir from the original reservoir fluid composition using the laboratory determined pressure-production history and retrograde liquid accumulation as guides. Equilibrium vaporization ratios for this calculation were modified from published data until the calculated dew point pressure and retrograde liquid accumulation agreed with the values observed in the laboratory. The calculated results are compared with the produced gas composition determined by low temperature analysis during constant volume laboratory experiments of pressure depletion behavior. This comparison shows that the calculation procedure is adequate for determination of gas phase composition. Data from field separation tests in low temperature separators are presented which verify the applicability of published equilibrium vaporization ratios for a wide range of separator conditions. INTRODUCTION A reliable prediction of the pressure depletion performance of a gas-condensate reservoir is necessary in determining reserves and evaluating field separation methods. The predicted performance is also used in planning future operations and studying the economics of projects for increasing liquid recovery. Because the flow of fluid in a volumetric gas-condensate reservoir is usually single phase flow, the pressure-depletion per-formake is primarily a function of the phase behavior of the reservoir fluid. The properties of a gas-condensate system of major importance are: (1) compressibility factor at reservoir temperature and pressure; (2) dew point pressure; (3) composition changes of the vapor phase with pressure depletion; (4) recovery of original in-place hydrocarbons at any pressure; and (5) retrograde condensate accumulation. These properties are most generally determined by a pressure depletion-type experiment on recombined separator gas and liquid samples in the laboratory. ldeally the pressure-depletion performance can be calculated from the composition of the original reservoir fluid if the reservoir temperature and initial pressure are known.1,2,3 It has been reported "... comparison of such computations with depletion-type ex-periments on recombined samples in the laboratory have yielded results that appeared to be entirely adequate.". The success of such calculations is determined by the equilibrium vaporization ratios chosen, especially those for the higher boiling point hydrocarbons. It is the purpose of this paper to present a method for computing the change in composition of the vapor phase during pressure depletion by production using laboratory determined properties of the system to guide the calculation and to illustrate the use of the method with data from the Cockfield "D" sand of Washington field, St. Landry Parish, La. Results of field tests and laboratory analysis are included. As a result of this reservoir fluid study, a cycling program has been evaluated, the fidd has been unitized, and the cycling started in July, 1956.

Jan 1, 1958

By Warren E. Wilson

PRESENT-DAY design of launders is essentially an art depending to a marked degree upon the experience of the designer, whose problem is that of determining the dimensions of a conduit that will transport the pulp within the physical limitations of the plant and in the most economical manner. This paper has been prepared in an effort to place launder design upon a more scientific basis. A method is developed from elementary principles and presented in a form that may be used directly by the designer in determining launder dimensions.. The equations that are developed are believed to represent an advance over older ones, in that they give due consideration to all the pertinent variables, either including them in the analysis or showing that they may be neglected within the limits of applicability of the equations. Experimental data from several sources are used in evaluating the coefficients that are not determined in the mathematical analysis. On the basis of the material presented, it is concluded that launders may be designed with a much greater degree of accuracy than previously believed possible, when due consideration is given to all the factors involved in the problem. However, a great deal of work still remains to be done in the laboratory before a complete answer to all the questions in launder design can be made available. HISTORY OF LAUNDER DESIGN Among the references1-11 are cited accounts of many experiments that have been conducted in an effort to advance the knowledge of the flow of liquid-solid mixtures in flumes and pipes. With three notable exceptions, this work was carried on in such a manner that the results have limited value in solving the general problem, since not all the pertinent variables were measured and controlled. The exceptions are found in the works of Blue,6 Gilbert,7 and Blatch,11 who exercised great care in controlling and measuring all the significant quantities involved in the experimentation. It is notable that much of the work done by men directly connected with the mineral industries1-4 lacks somewhat in completeness, owing apparently to preconceived notions concerning the factors that determine the flow. For example, many measurements on flow in pipes and flumes carrying liquid-solid mixtures determined only the slope and percentage of solids, with no mention of size of particles, depth of flow, roughness of channel or specific gravity of solids. Material in current handbooks8,9 and textbooks is based largely on the experimental work cited above. Although most discussions of the topic-include statements that the results to be obtained by using the data presented are limited by the fact that all variables have not been considered, it is

Jan 1, 1943

By G. L. Craig

In order to meet the unprecedented demand for copper it has proven necessary not only to develop every primary source, but also thoroughly to exploit the vast reservoir of metal in use that is not directly serving the war effort. To accomplish this, industry has been called upon to use its resourcefulness for developing methods of recovery that have not been previously utilized. It is in this connection that we have been asked to review the methods suggested for recovering the basic constituents of various types of the so-called clad or composite steels. As a background for a discussion of recovery processes, it seems appropriate to consider clad materials in general and their processes of manufacture. A composite steel has been defined as one consisting of two or more component parts of which the smallest shall comprise at least 3 per cent of the total mass. Clad materials or composites are produced commercially by several different methods of which the most important may be classified as: I. The Blacksmith or Forge Weld Method. This method is limited to carbon steels or low-alloy steels as the presence of even small amounts of common alloying metals prevent the formation of a satisfactory weld. The principle is the application of pressure to sections in contact at elevated temperatures. Because of the tendency of the iron to oxidize, borax is generally used as a flux to absorb the iron oxide. 2. Casting Process-In this method a composite ingot, billet or cake is produced by pouring one metal onto or about another. The bond may be accomplished by the action of the molten metal against a solid, in which case the bond may be referred to as mechanical; while in other instances alloying occurs at the interface producing an anchor by the formation of component parts of the two materials. 3. Cementation Process.-In this process any number of combinations of metallic and nonmetallic constituents which are mixed together may be used as a bonding agent. The combinations, whatever they may be, are placed between the materials to be joined and subjected to pressures at elevated temperatures to produce the desired bond. 4. Fusion Welding Processes.-Gas and electric joining for direct use or subsequent fabrication. 5. The, Assembly Process.-This method involves the joining together of prefabricated bars or plates followed by hot and/or cold working the assembly to the desired finished form. This method is advantageous in many cases because of its flexibility on small quantities as compared to the casting method. It is also possible to control the relative proportion of components more accurately. In this discussion we are concerned only with the scrap resulting from the manufacture of clad materials and our interest,

Jan 1, 1943

The Carlin gold deposit is located in northeastern Nevada about thirty-five miles by road from the town of Elko. Following the staking of six square miles &apos;of ground, a drilling program outlined a fine ore body mineable by open pitting. The resulting mine turned out to be the largest open-pit gold operation in the world, until the Rosario Pueblo Viejo operation was started in 1975. Because of the high profitability forecast at the then $35 gold price, construction of a 2000 stpd mill was commenced on a crash program and was completed for Newmont Mining Corporation by Bechtel Corporation in ten months. Production was started in early 1965. The gold mineralization occurs in marine-type sediments, chiefly silt- stones and limey shales, and the ore characteristics make for a difficult materials-handling problem. At 5% to 6% moisture the ore is dusty during crushing, but even a light rain or snowfall virtually turns the material into a slurry. Crushing this sticky ore below 314 in. (19 mm) in the dry season and 1 in. (25.4 m) during the winter is extremely difficult and leads to problems with conveyors, chutes, and fine ore storage. The initial flowsheet for Carlin&apos;s crushing plant used a 5 ft by 22 ft (1.52 m by 6. 7 m) vibrating feeder -grizzly under the 60 -ton dump pocket for feeding the 42 in. by 48 in. (1067 mm by 1220 mm) single toggle jaw crusher and a 5 ½ ft (1.52 m) standard cone crusher in closed circuit with a 6 ft by 12 ft (1.83 m by 3.66 m) vibrating double - deck screen. Because continual packing of fines in the vibrating feeder pan would cause frequent plant shut-downs to remove the fines with jack hammers, the decision was made to replace the vibrating unit with an apron feeder and stationary grizzly ahead of the jaw crusher. A dribble belt was also installed under the apron feeder. This installation has greatly improved the feeding of the pit run ore to the .primary jaw crusher. Mining at Carlin is done by a 5 yd shovel and 7 ½ and 10 yd front-end loaders, and ore transport is by several sizes of trucks from 30 to 75 tons capacity. These pit haulage trucks dump onto stockpiles adjacent to the primary crusher. Ore is then fed to the dump hopper by front- end loaders only when the crushing plant is operating. This extra handling procedure is necessary because plant delays caused by problems with wet ore in the secondary crusher resulted in the ore setting up or packing in the dump pocket. Solidified material in the dump pocket would in turn delay truck haulage. The substitution of an

Jan 1, 1978

By E. Brunner, E. S. Mardock

A method of measuring oil saturations in cores or sand packs by neutron scattering is described. This method permits local SatUrations to be measured in a core enclosed in a steel pressure vessel without interrupting the flow. calibration data and a saturation distribution measurement obtained with the apparatus are included by way of illustration. Introduction In laboratory flow experiments designed to study the mechanism of oil production it is frequently necessary to measure the oil saturation in a core or sand pack containing Oil, gas, and perhaps brine. It is sometimes desirable that the saturation measurement refer to a relatively small portion of the core, so as to eliminate end effects; that it be made without interrupting the flow, and that it be applicable to a core enclosed in a steel Pressure vessel capable Of withstanding the Pressures encountered in petroleum reservoirs. None of the usual methods of measuring saturation meets all Of these requirements. To measure the gas saturation by observing the apparent compressibility of the gaseous Phase1 would require the interruption of the flow and would give an average saturation for the whole core. An electrical conductivity method is available for measuring brine saturations,2,3 but it is not applicable to oil. A radioactive tracer might be used if a suitable substance could be found that would dissolve in the oil, emit gamma radiation, and not be adsorbed on the sand, the steel core holder, or in an aqueous- phase. The large gamma-ray background from the mass of radioactive oil in other parts of the apparatus might, however, be undesirable. There remain for the saturation measurement methods involving the absorption or scattering of some penetrating radiation produced outside the apparatus. It might be possible to use X-rays or gamma rays; but these radiations would be so much less strongly absorbed and scattered by the oil than by the steel walls of the core holder and by the sand that it seems doubtful that much precision could be attained. In a beam of neutrons, however, there is a radiation that is very penetrating and, moreover, its scattering by substances containing hydrogen, such as oil, is qualitatively different from that occasioned by other materials. It would seem possible, and has proved to be quite practicable, to measure oil saturations accurately under the required conditions by means of neutron scattering. The first, to our knowledge, to suggest neutron scattering as a means of measuring oil saturation were F. Brans and ,. A. Bottema,4 of the Amsterdam laboratories of the Bataafache Petroleum Maatschappij, who made a few preliminary experiments to test the method while they were engaged in exploring the possibilities of neutrons for well-logging purposes. A comprehensive account of neutrons and their behavior will be found, together

Jan 1, 1946

By E. S. Mardock, E. Brunner

A method of measuring oil saturations in cores or sand packs by neutron scattering is described. This method permits local SatUrations to be measured in a core enclosed in a steel pressure vessel without interrupting the flow. calibration data and a saturation distribution measurement obtained with the apparatus are included by way of illustration. Introduction In laboratory flow experiments designed to study the mechanism of oil production it is frequently necessary to measure the oil saturation in a core or sand pack containing Oil, gas, and perhaps brine. It is sometimes desirable that the saturation measurement refer to a relatively small portion of the core, so as to eliminate end effects; that it be made without interrupting the flow, and that it be applicable to a core enclosed in a steel Pressure vessel capable Of withstanding the Pressures encountered in petroleum reservoirs. None of the usual methods of measuring saturation meets all Of these requirements. To measure the gas saturation by observing the apparent compressibility of the gaseous Phase1 would require the interruption of the flow and would give an average saturation for the whole core. An electrical conductivity method is available for measuring brine saturations,2,3 but it is not applicable to oil. A radioactive tracer might be used if a suitable substance could be found that would dissolve in the oil, emit gamma radiation, and not be adsorbed on the sand, the steel core holder, or in an aqueous- phase. The large gamma-ray background from the mass of radioactive oil in other parts of the apparatus might, however, be undesirable. There remain for the saturation measurement methods involving the absorption or scattering of some penetrating radiation produced outside the apparatus. It might be possible to use X-rays or gamma rays; but these radiations would be so much less strongly absorbed and scattered by the oil than by the steel walls of the core holder and by the sand that it seems doubtful that much precision could be attained. In a beam of neutrons, however, there is a radiation that is very penetrating and, moreover, its scattering by substances containing hydrogen, such as oil, is qualitatively different from that occasioned by other materials. It would seem possible, and has proved to be quite practicable, to measure oil saturations accurately under the required conditions by means of neutron scattering. The first, to our knowledge, to suggest neutron scattering as a means of measuring oil saturation were F. Brans and ,. A. Bottema,4 of the Amsterdam laboratories of the Bataafache Petroleum Maatschappij, who made a few preliminary experiments to test the method while they were engaged in exploring the possibilities of neutrons for well-logging purposes. A comprehensive account of neutrons and their behavior will be found, together

Jan 1, 1946

By D. C. McLean, S. A. McKay

The purpose of this paper is threefold: 1) to describe actual ground control installations made at the various mines of the International Nickel Co. (Canada) Ltd mines in Sudbury, Ont. during a planned test program. 2) to suggest new ground control techniques which are now possible by the use of fully grouted bolts 3) to indicate the possible economic advantages to be gained by the use of resins and resin grouted bolts to control difficult ground conditions. Were a theme selected for this paper it would be: "Preserve the original roof in best condition possible by the use of smooth blasting techniques and fully grouted roof bolts — since the original rock is the best and cheapest material available for ground support." TYPES OF BONDED BOLTS As has been shown previously, there are several ways in which a bolt may be bonded. These are illustrated in Fig. 1 and 2. There are three general types of grouted bolts: 1) pretensioned, 2) post-tensioned, and 3) untensioned. The type which will be of most benefit to the user will depend upon the particular ground support problem involved. Despite the many arguments propounded for the necessity for using a tensioned bolt, ample evidence exists from actual experience that untensioned bolts can be effective in many instances. The outstanding characteristic of a grouted bolt is that it provides the user with a variety of rock consolidation techniques heretofore unavailable with conventional rock bolts. Many of the unusual characteristics of grouted reinforcing bar have been evaluated by researchers in the concrete structure field.&apos; Underground application has largely been pioneered in the construction field, with especially good work being reported from the Snowy Mountains Hydroelectric Authority in Australia. Techniques developed there using cement grouted bolts are now being adapted in many large government construction projects in this country with excellent results. The ap- plications described in this paper are those in which Cyanamid&apos;s Roc Loc Mining Kits were used exclusively. SLUSHER DRIFTS AND FINGER RAISES (BOX HOLE BROWS, DASHES) A common mining problem especially where block caving methods are applied is that of maintaining the roof in slusher trenches particularly at the intersections of the trench with the feed raises (box holes) through which the large fragments of broken ore tumble. Typical sections are shown in Fig. 3 and 4. In Fig. 3, the drift is normally driven 7 ft wide by 8 ft high initially. The rock involved is a hard norite (diabase) which is usually competent but has "block cleavage". This roof has a tendency to fall out in large blocks when subjected to operating stresses. Depending upon the initial condition of the roof, the drift is either lined with 2 to 3 ft of concrete immedi-

Jan 1, 1964

Smoky Valley Mining Company, Round Mountain, Nevada, was the pioneer operation designed for large scale heap leaching of crushed gold ores. It is located in the Big Smoky Valley which stretches 160 km (100 miles) through central Nevada west of the Toiyabe Mountain Range. Gold was first-discovered at Round Mountain, 88 km (55 miles) north of Tonopah, in 1905; and mining in the area included placer operations, which ran from 1946 to about 1960. Smoky Valley Mining Company is a partnership of Felmont Oil Co., Case-Pomeroy & Co., and Copper Range Co., with the latter being wholly owned by Louisiana Land and Exploration Co. In 1969, an option on the Round Mountain property was acquired by Copper Range, and during 1974 a decision was reached to proceed with mine development and plant construction. Ore reserves were reported at 10,537,000 mt (1 1,617,000 st) of 2.09 g per mt (0. 061 oz per ton) gold using a cut- off grade of 0.69 g (0.02 oz). Silver content was approximately 2.4 g per mt (0.07 oz per ton) and the waste to ore ratio was about 1: 1. By the end of 1976 heap leaching was in operation. The ore is a rhyolite tuff, sometimes described as a gold porphyry with highly abrasive qualities but which does not break down into slimes upon contact .with cyanide solutions. Gold is unevenly distributed through the ore but as a whole it is in a very finely divided state. Climatic conditions are extreme in central Nevada. Summers are hot and dry while winters are windy and cold with subfreezing temperatures. Elevation of the property is about 1,920 m (6,300 ft). Precipitation averages 203 mm (8 in.) per year. Until February of 1980, leaching was continued until the temperature reached minus 2ºC (28º F), and about 10 months leaching was the average. Water for the operation is drawn from the Toiyabe Mountains through a 13. 7 km (8. 5 mile) pipeline, originally installed in 1915, or from wells in the valley bottom. The plant requires make-up water at the rate of about 1,500 liters per min (400 gpm). On a schedule of three shifts, seven days per week, the daily output at Round Mountain amounts ,to 12, 700 mt (14, 000 st) consisting of 6,350 mt (7,000 st) each of ore and waste. Ore is hauled with a fleet of 45 mt (50 st) trucks and dumped into the 1,0.70 by 1,650 mm (42 by 65 in. ) gyratory primary crusher located near the pit. The primary

Jan 1, 1981

By Michael Hoch, Seong Kwan Rhee

The ternary system Zr-Cr-0 was investigated at 1200°, 1500°, and 1700°C. The isotherms at these temperatures were determined by metallographic and X-ray diffraction analysis of carefully selected alloys. AS a part of a series of investigations1-4 of the ternary and quaternary phase diagrams on refractory metals and their compounds, the ternary system Zr-Cr-O was investigated at 1200°, 1500°, and 1&apos;700°C. The binary diagrams Zr-Cr, Zr-O, and Cr-0 as reported by Hansen5 and Levin et a1.&apos; and the existence of a ternary coompound ZrsCrsO (q-carbide structure a. = 11.96A) provided a good base for this investigation of the Zr-Cr-O phase diagram. MATERIALS The materials used and their suppliers were: Zirconium powder, 99.4 pct pure, Charles Hardy, New York; Zirconium dioxide, Fairmount Chemical Co., Newark, N.J.; Chromium powder, 99.85 pct pure, Fairmount Chemical Co., Newark, N.J.; Chromium sesquioxide, 99.86 pct pure, J. T. Baker Chemical Co., Pillipsburg, N.J. Though the materials used were not "hyperpure", the impurities present do not affect the results (lattice parameters, phase boundaries) within the experimental accuracy. EQUIPMENT AND PROCEDURE The detailed procedures and equipment used for this investigation were similar to those described elsewherel&apos; "ith the exception that in this study an induction-heated argon-atmosphere furnace was used. The latter furnace was used to prevent the vaporization of chromium metal in samples in the higher temperature range (above 1200°C). The tungsten crucible was induct ion-heated in a vertical quartz tube filled with argon gas. The quartz tube was 1-1/2 in. in diameter and 10 in. long; it was connected at the top and bottom to water-cooled copper plates. The argon gas of a purity 99.995 pct was further purified by being passed through zirconium metal chips which were maintained at 800°C in a silica tube 1 in. in diameter and 30 in. in length. The furnace was flushed with argon gas for an hour before starting heating; during heating, a slight (3 cm oil) overpressure of argon was maintained in the system. Power was supplied by a 20-kw Ther-Monic Induction Generator. The samples rested on a tungsten-wire basket; the wire basket was connected to a tungsten wire which passed through the tungsten crucible lid, and entered the system on top through a Wilson-type seal. By pulling on the wire, the sample was removed from the crucible and dropped to the water-cooled copper base of the furnace. Because of the presence of argon gas, the cooling of the sample was even more rapid than in the vacuum furnace.&apos; EXPERIMENTAL RESULTS AND DISCUSSION 1) Isothermal Section at 1200°C. The compositions investigated have been numbered within the phase diagram, Fig. 1, and all the pertinent information about the samples can be found in Table I. This table lists the composition of the samples, the phases present in the room-temperature diffraction patterns, the phases detectable in the microstruc-ture, and calculated lattice parameters of the a-zirconium phase. The shapes of the various phase

Jan 1, 1964

By F. F. Craig

Many full-scale waterflooding operations are preceded by pilot floods, one purpose of which is to provide an estimate of recoverable oil. A laboratory model study was made to determine the influence of the producing wells&apos; effective productivity on the oil recovery efficiency of single five-spot pilots, as well as single injection well pilot floods. The effective productivity is indicated by the value of Condition Ratio, defined as the actual well productivity to that of on undamaged and non-stimulated, normal-sized well in the same formation. The effects of initial gas satrcration and mubility ratio on recovery eficiency were also investigated in this model study. Model test results skowed that at favorable mobiliry ratios, a five-spot pilot flood can provide a direct quantitative estimate of the recoverable oil in the pilot area. If the pilot producer&apos;s Candition Ratio is 2.2 or more, upwards of 90 per cent of the recoverable oil in the pilot area is recovered from the inside producer, regqrdless of the mobility ratio or initial gas saturation. This Condition Ratio can be achieved with preyent fracturing techniques. Model studies also showed that over the range of imposed injection pressure differences and regional pressure gradients normally encountered in field operations, there was no effect on the recovery efficiency of a five-spot pilot waterflood. Model studies of single injection well pilot waterfloods showed that with no initial gas saturation, the total oil recovery at the offset producing wells can indicate the oil recovery possible by full-scale waterflooding. It is essential that the Condition Ratios of the offset wells be above 1.4. If an initial gas saturation exists prior to water injection, the recoverable oil cannot be directly evaluated by a single injection well pilot flood. However, the production per formance of such a flood can be used to provide information on volumetric sweep efficiency. INTRODUCTION Oil reservoirs are conlplex structures and cannot always be fully studied in the laboratory. Therefore, many operators consider it prudent to evaluate a waterflood prospect by means of a pilot flood. Pilot waterfloods generally involve one of two well arrangements: a single five-spot pilot waterflood, involving four injectors and an internal pilot producing well; and a single injection well pilot flood (sometimes called an inverted five-spot pilot) having one injector and four sur- rounding pilot producers. Some pilot floods are composed of multiple five-spot pilot patterns. To yield information applicable to field-wide performance, the pilot must be located in a representative portion of the reservoir. Pilot floods generally are conducted for one or more of the following reasons: (1) to determine whether water could be injected at desirably high rates, (2) to determine whether an oil bank or zone of increased oil saturation is formed by water injection, and (3) to estimate the oil recovery by waterflooding. Many of the early pilot water-floods were conducted for only the first two reasons. As soon as a buzz in oil production was obtained in the pilot, water injection was initiated throughout the entire lease or field. A number ot laboratory studies have been directed toward determining conditions under which a pilot flood could yield a quantitative estimate of the oil recovery possible by full-scale pattern flooding. One of the early studies of single five-spot pilot flooding&apos; showed that well damage to the inside pilot producer could reduce the total amount of oil recovered. In a study of the single injection well pilot flood pattern,&apos; the results indicated that if the model boundaries were no closer than a half-well spacing beyond the pilot pattern, the pilot performance in the laboratory is unaffected by these boundaries. In another study,? he effect of initial gas saturation and mobility ratio on the ratio of production to injection rate for various groupings of five-spot patterns was defined by mathematical and analog methods. In a study4 involving both potentiometric and flow model experiments at a mobiliry ratio of unity, four different pilot patterns were studied. These included a single five-spot, a single injection well pilot, a cluster of four single injection well pilots and six inverted five-spots. In this study the ratio of well diameter to the distance between injection and producing wells was held constant at 1:1000. The effect of the 7 ratio-—the ratio of the pressure drawdown at the producing wells to the pressure build-up at the injection wells on the pilot performance-was studied. The values of 7 ratio ranged from 0 to 0.34. Results showed that both the total oil recovery and the total fluid production from the pilot relative to the cumulative injection increased with increasing values of the 7 ratio. The effect of both the ratio of injection to producing rates and mobility ratio on the oil recovery performance of a liquid-saturated single five-spot pilot flood was studied in a series of flow model tests.5 Rate ratios ranged from one to four, and mobility rates ranged from 0.1 to 10. Resulls of these tests showed that at low rate ratios, the pilot producers may recover up to four times the recover-

Jan 1, 1966

By E. I. Radzinovsky, D. W. Dareing

This paper presents theory which is used to predict rock-bit bearing life reduction due to simple harmonic variations in bit forces. The theory is based on the premise that if a constant load acts for a certain fraction of the life which the bearing would have if that constant load were applied for its entire life, then the same fraction of thelife of the bearing is consumed. Total bearing life is related to simple harmonic variations in bearing life associated with instantaneous bearing loads. The results show that rock bit bearing life is not affected appreciably by forces commonly impressed upon a bit, but it is affecied appreciably by relatively large dynamic bit forces occasionally encountered during drilling. In addition, the results show that the life of sealed bearings is more sensitive to bit force variations than is the life of unsealed bearings. INTRODUCTION Roller bearings are important components in roller cone rock bits because they transmit a large portion of the drill collar weight to the formation being drilled. Unfortunately, they have a relatively short life under down-hole drilling conditions. Roller bearings are usually the first bit components to fail, and their failure leads immediately to failure of the entire bit. Short roller bearing life, and thus short bit life, is due mainly to high unit loads transmitted by the bit and to the adverse environment in which the bearings operate. The results of the study discussed in this report show how dynamic bit forces also affect roller bearing life. The purpose of this paper is to discuss theory developed to predict the effect of different magnitudes of periodic bit forces on roller bearing life. Theoretical results are used to compare the life of rock bit roller bearings subjected to steady forces to the life of rock bit roller bearings subjected to unsteady forces similar to the type of unsteady forces measured at the bit with a special downhole recording instrument. BACKGROUND AIanufacturers of bearings have conducted laboratory tests which show how bearing life is affected by steady bearing load. 1 The well-known empirical equation which defines bearing life follows from bearing test data. It is: where L = bearing life, hr P = bearing load, Ib C = constant q = exponent (constant). The effect of environment on bearing performance is manifested through the exponent q and the constant, C. King,2 in similar tests conducted on roller bearings used in rock bits, showed that, in addition to the load, the environment (abrasive materials, chemical components, etc.) greatly affects bearing life. His data, which show how the life of roller bearings in a 7-7/8-in. W7R bit rotating at 60 rpm is affected by bit weight and fluid environment, are displayed on a log-log plot by broken lines made up of straight line segments. Each broken line corresponds to a given environment. One segment (q = 1.4) of the broken line corresponding to a fluid environment of barite mud is shown in Fig. 1 along

Jan 1, 1966