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By H. H. Kaveler, Z. Z. Hunter

Variation of the horizontal permeability (parallel to the bedding plane) in the vertical section of reservoir rocks has long been observed as a characteristic of a normally heterogeneous system which reservoir rock represent. The use of a recently developed water injection profile device offered opportunity to measure with a high degree of reliability the rate of inflow of water into Burbank sandstone in wells previously cored. Water injection profiles were not correlative with core permeability profiles in such wells. Apparently the vertical permeability substantially influences the flow between strata in a formation in a manner as to void the usual conclusions that have been drawn from consideration of the horizontal permeability measurements alone. The results obtained in comparing water injection profiles with horizontal permeability profiles suggest that many of the usual production operations based upon "selective" behavior or treatment of rock exposed in well bores need to he re-valuated and re-examined. INTRODUCTION Petroleum reservoir rock are heterogeneous systems. Heterogeneity exists in respect to lithologic character insofar as such rock are composed of distinguishable solid phases. Heterogeneity also exists in respect to certain properties, such as porosity and permeability, that vary due to variation of the physi-cal structure of the rock. Except in exceptional cases, both the horizontal permeability (measured parallel to the bedding planes) and the vertical permeability (measured perpendirularly to the bedding planes) exhibit significant variation in any common source of supply. The variation in horizontal permeability. as reflected by con. analyses. has drawn the greatest attention of petroleum technologists probably out of the general notion that the mass movement of fluids in a reservoir is predimonantly in the horizontal direction. Furthermore, in the usual case, the rock permeability measured in the horizontal direction is greater than that in the vertical. The variation of horizontal permeability of reservoir rock has been the basis for developing a number of operating practices and procedures intended to improve the petroleum production operation. Many such procedures are referred to as "selective" in the sense that the practice is intended to control the flow to a more. or less. permeable interval within the common source of Supply. It is often said that such practices are "tailored" to the permeability profile. The practices referred to involve, among others, the following: selective perforation of casing; selective shooting, acidizing and plugging: plugging back to intervals of low permeability; and, regulation of flow to prevent coning of water or gas, or irregular encroachment of water or gas. Certain expressed notions involving a concept of "by-passing," or "trappingl" that are held to be particularly harmful in causing the avoidable loss of recoverable petroleum have grown from observed variations in the horizontal permeability. Oftentimes estimates of the reserve of a common source of supply are tempered by conclusions relating variation in horizontal permeability to recover-ability of the oil-in-place. Certain conclusions attributed to the significance of the variation of the horizontal Permeabilitv often extend to the design and operation of pressure-maintenance projects involving both water flooding and gas-injection. Many advocate increasing the number of injection wells, advocate maintaining uniform and equidistant input-output well patterns, or advocate so-called "dispersed" gas-drive techniques rather than gas-cap injection because the permeability profile of cored wells is supposed to indicate that "by-passing" or "trapping" would otherwise exist. It is important, therefore, to have an opportunity to test whether the variation in the horizontal permeability found through core analyses of a typical reservoir rock is sufficient to establish the paths of fluid flow in a reservoir. It is particularly important to have an opportunity to determine whether flow at the sand face of a well conforms to the permeability profile as established by core analyses. In that manner, the merit of certain 50-called "selective" operating procedures and other notions may be evaluated. The purpose of this paper is to compare horizontal permeability profiles of wells in the Bartlesville (Bur-bank) sandstone with water injection profiles, for the purpose of showing that there is no correlation between the horizontal permeability of a core and the water intake characteristics of a typical sandstone. GENERAL CHARACTERISTICS OF BARTLESVILLE (BURBANK) SANDSTONE The Bartlesville sandstones of Northeastern Oklahoma are off-shore bar deposits.' Although other reservoirs had different processes associated with their deposition or with the formation of their porous, permeable structure, the l!artlesville sandstones on which these field Fields were made are, in every respect. typical petroleum reservoir rock. The permeability of the Bartlesville sandstones shows a typical variation in both the horizontal and vertical direction. Furthermore, the permeability profile logs of wells in any pool are not correlative, even as between wells as close as 660 ft and 330 ft apart.'. The same condition exists in such sand-tones as the Jones Sand at Shuler' and is the ordinary and usual characteristic of reservoir rock. THE FIELD DATA The data reported herein are those obtained from coring of nine wells on the center of ten-acre locations for the purpose of providing water-injection wells in the Bartlesville (Burbank)

Jan 1, 1952

By V. P. Yashin

Modern trends in the use of autogenous grinding of minerals have been investigated by Mekhanobr Institute. The conclusions drawn are based on experimental and theoretical investigations by the author and his coworkers. A method is suggested for determining the efficiency of converting from ball milling to autogenous grinding. A qualitative interpretation is given for comminution theory using both methods. This interpretation is used as a basis for considering both the principal trends in increasing use of primary autogenous grinding and the results of such in industrial application. Data are given from testing some ores from USSR deposits for the effect of the ore Preparation step on subsequent metallurgical treatment. Autogenous grinding is shown to be widely used in various USSR industries.

Jan 1, 1980

By S. F. Radtke, J. A. Snyder, R. M. Scriver

An automatic, continuous casting arc furnace employing a nonconsum-able electrode and a direct current arc has been constructed and operated successfully for titanium. A comparison of the properties of arc and induction-melted titanium indicates that where high ductility, formability, and toughness are required, arc-melted metal is preferable. BECAUSE of the reactivity of titanium metal with all known refractories and the common atmospheric gases, melting of the metal presents numerous problems. It is necessary to provide an inert atmosphere in the furnace as well as a crucible material that will not react with the molten metal, if a ductile ingot is to be produced. Two special furnaces have been developed that meet the requirements and one, the induction heated graphite furnace, has been described in some detail.' Little information is available for sizable units wherein power is applied to the melt through an arc, and the dearth of technical information on such a furnace prompted this report. It has been demonstrated clearly that arc melting produces titanium metal with superior toughness, ductility, and formability. To produce titanium ingots with these properties, an automatic, continuous casting arc furnace has been developed and is described herein. The history of arc melting may be traced to 1800, when Sir Humphrey Davy2 first experimented with Volta's electric battery and found that light could be produced and an arc formed between two carbon points attached to the cell. The discovery of the arc was followed by the design and construction of an arc furnace by Napier," in 1845, for the reduction of metal oxides. In 1853, Pichou' described a similar furnace, although it was not until the discovery of the dynamo in 1867 that the arc furnace could achieve commercial significance. In 1878, Siemens- esigned the first arc furnace intended for the melting of metals and by 1882 had melted steel and platinum successfully. . This was followed by Moissan's" classical work with the arc furnace in 1892. W. von Bolton,' in 1905, found that the arc furnace was suited admirably for melting refractory metals. In his work with tantalum, no suitable refractories for retaining the molten metal were found to exist. Together with Otto Simpson, he developed an arc furnace with a water-cooled copper crucible in which tantalum could be melted without contamination. This technique proved eminently successful. In his paper on the preparation of ductile titanium, Krolle first described an application of the von Bolton furnace to the melting of this metal. The

Jan 1, 1952

By George B. Clark, John W. Brown, Hemendra N. Kalia, Ronald R. Rollins

A new theory for three dimensional collapse of conical liners shows why the two dimensional theory may offer a good approximation. Shaped charge design parameters and rock target properties were investigated to determine their effects on penetration and breakage. Penetration in dolomite is somewhat similar to that in steel, but copper does not have markedly better penetration capabilities than brass. Several metals, liner thicknesses, cone angles and standoff ranges for each were investigated. Effective standoff is greater for aluminum than more dense metals. Optimum geometry appears to approximate that for metal targets. Resistance to penetrations was greatest for a red granite and dense siliceous rocks, and least for dolomite and porous sandstone. Hardness and compressive strength appear to be two important conventional proper- ties. The first order law does not apply to the rocks tested. Dolomite may be drilled with shaped charges, the holes sprung and round blasted successfully.

Jan 1, 1971

By Orson Shepard

TEXTBOOKS on fire assaying list the following standard methods of assaying sulphide ores: (1) scorification, (2) litharge-niter, (3) soda-iron, (4) roasting, (5) combination wet and fire. The litharge-niter method has proved the most satisfactory, and is the usual method for assaying sulphide ores and concentrates. It gives good results when suitably conducted and when lead buttons of uniform size are produced so that the cupellation temperature can be properly controlled. The main objection to the method is the inconvenience of determining the amount of niter to add to each assay charge to produce lead buttons of suitable size from a set of fusions. For the assay of different materials, the niter requirement varies with the particular sulphide minerals present, the amount of sulphide minerals present, the slag composition, and the rate of heating the charge in the furnace. Except for some materials, so uniform in composition that the same amount of niter can be used in assaying all samples, the amount of niter must be determined for each sample to be assayed. This is done by either: (1) calculation from an estimate of the kind and amount of sul-phide minerals present in the sample, or (2) a preliminary fusion. Some assayers use one method and some the other. The estimation method takes the least time; but much experience is required to obtain close estimates on a wide variety of materials. At best, the sizes of the lead buttons obtained vary considerably. The preliminary fusion method usually gives lead buttons of fairly uniform size, although sometimes there is a variation because the oxidizing power of niter varies a little with the charge. This variation can be eliminated by two preliminary fusions: one to determine the reducing power of the ore, and the other to determine the oxidizing power of niter in the charge. The objection to the prelimi-nary fusion is the extra time and expense involved.

Jan 1, 1939

By E. R. Gilliand

KNOWLEDGE of a large number of the physical properties of the hydro-carbons is needed in the calculations and studies of the production engi-neer. Since experimental data on these properties of the individual hydrocarbons and their mixtures are available in only a relatively few cases, the use of generalized correlations has developed rapidly in the last decade. The generalized correlations of pressure, volume and tem-perature,1 enthalpy,2 and vapor-liquid equilibria,3 on the basis of reduced temperatures and pressures, are outstanding examples of this develop-ment. These correlations are of particular value to the production engineer interested in the flow of oil and gas, since they can be used to estimate the conditions under which segregation of phase occurs as well as the composition, density, and relative amounts of the phases. The technique of using the correlations for such estimations has been pub-lished by several authors¢ and will not be considered in this paper. A considerable number of data have been obtained to check the generalized pressure-volume-temperature correlations, and these data indicate that such relations hold for the hydrocarbons from methane to heptane. The accuracy is in general sufficient for most engineering pressure-volume-temperature calculations. However, the generalized correlations of enthalpy and vapor-liquid equilibria have in general been developed from the pressure-volume-temperature correlations by thermodynamic calculations and only a relatively few experimental data are available to check these calculated values. The calculations from pressure, volume and temperature are likely to lead to large errors in the calculated enthalpy and vapor-liquid equilibria. Thus, in the calculations of enthalpies, slopes of the pressure-volume-temperature data are employed, and determining these slopes can greatly amplify small errors in the original data. In the vapor-liquid equilibria calculations it is necessary to have the pressure-volume-temperature relations of the mixture, and the latter properties are much more questionable than those of pure components, particularly in the critical region. A considerable number of experimental data are

Jan 1, 1939

By Donald E. Meyer

High current-low voltage EB-gun evaporation in an oil-free ultra-high vacuum system was found to be necessary, though not sufficient, for stability (300°C, 106 v per on) of aluminium gate MOSFET's and MOS capacitors not stabilized by a phosphorous glaze. five characteristics of the equipment used: 1) Vacuum purification of the aluminum charge, 2) Ionization of the evaporant by the electron beam, 3) X-ray formation, 4) Residual gases during evaporation, and 5) Metal film structure were studied as Possibly significant in MOS fabrication. EVAPORATION of contact metals common to the semiconductor industry historically has been accomplished with oil diffusion pump systems and various resistance heated evaporant sources as dictated by the type of metal evaporated. To meet a need for greater reliability of semiconductor devices, other metallization methods were developed. A good example would be application of the moly-gold contact system to integrated circuits with deposition by RF or triode sputtering.' More recently, fabrication of stable metal-oxide-silicon devices and circuits has put new demands on metallization. The purity of the thin metal films composing MOS structures is critical, particularly at the metal-oxide interface, and ultra-high vacuum metallization using sputter-ion pumping and electron beam gun (EB-gun) evaporation are well suited for the task. At this laboratory aluminum has been the most common contact-gate metal for both MOS capacitors and MOSFET's. In the earliest work with MOS capacitors, aluminum was evaporated from wetted tungsten filaments using both diffusion pump and ion pump vacuum systems. In spite of clean oxide techniques these capacitors were unstable under bias-tempera-ture stressing. Only after a switch to EB evaporation of aluminum were stable capacitors produced. Using the same techniques it was possible to make MOSFET's with equivalent stability. Stability data for a discrete MOSFET is shown in Fig. 1. This is a "clean" oxide gate (no phosphorus stabilization or no etch back of a thicker gate) having a thickness of lOOO? thermally grown on the (111) plane. Gate length after diffusion was 0.24 mils, and the devices were hermetically sealed. Stressing conditions were 300°C and 106 v per cm applied alternately as a positive and negative field for 10 min, 50 min, and 4 hr for a total stress time of 10 hr. An initial shift in turn-on voltage of 0.1 v was detected for 10 min of positive bias. All evidence at this laboratory indicated that while EB-gun evaporation of ultra-high purity aluminum was not sufficient for 300°C stability, it did seem to be necessary. There may well then be something inherent in the EB-gun deposition used which enhanced stability, and probably no single factor existed but rather a series of factors. It is the purpose of this paper to report on some of the investigations carried out to learn more about EB-gun evaporation in ultra-high vacuum systems. EXPERIMENTAL DESCRIPTION The EB-gun was self accelerated, had a maximum power rating of 10 kw, and used a water-cooled copper crucible able to hold a 20-g aluminum charge. The electron beam was bent 180 deg and focused by an electromagnet which also provided movement of the beam across the crucible. Normal power conditions in this work were 9 kv and 300 to 600 mamp. The gun can be described as high-cur rent/low-voltage and was quite different in its mechanism of operation from EB-guns with much higher acceleration potentials. An oil-free vacuum system capable of 5 x 10- l0torr, a quartz crystal rate and thickness monitor and a quadruple mass spectrometer completed the evaporation system, Fig. 2. A typical evaporation cycle consisted of a 3 to 4 hr pumpdown to the upper l0-9 range and evaporation at l0? per sec with the pressure in the bell jar not rising above 1 x 10"7 torr. Thickness control was 5 pct or less and could be automatically monitored and controlled. Five phenomena associated with the EB evaporation and considered as possible contributors to Ma performance included a purification effect, ionization of evaporating aluminum, X-rays, constitution of vacuum ambient during evaporation, and film structure dependence upon evaporation rate. These phenomena are now discussed. Vacuum Purification. The design of the EB-gun permitted purification of the aluminum charge by vacuum outgassing. Particular features included an efficiently water-cooled copper hearth with a capacity of over 20 g of aluminum and the capability for sweeping the beam across the charge. Such capacity meant that aluminum had to be added only after about every fifth evaporation. A new charge was not required each evaporation as is necessary with filament evaporation. An oxide "scum" which appeared on the charge could be completely cleared from the top hemisphere of the charge by sweeping with the beam prior to opening the shutter. An indication of the purifying effect was obtained by a series of analytical measurements on incoming aluminum, after melting but with little vacuum out-gassing, after 30 min outgassing, and the evaporated film itself. Either a solids (spark source) mass spectrometer or an emission spectrometer were used for analyzing the aluminum charge. Analysis of the evapo-

Jan 1, 1970

By L. S. Reid

THE study of the flow of oil and gas mixtures through oil-bearing formations has received special attention from the petroleum industry within the past few years, and has resulted in a series of research projects based upon various phases of the flow of heterogeneous fluids through porous media. Obviously, the low cost of producing oil during the flowing life of a well makes it desirable to obtain production by natural flow as long as possible and to effect a maximum recovery of oil and gas by the utilization of reservoir energy through efficient methods based upon a thorough knowledge of reservoir characteristics. Despite the extensive research that has been carried out, there is little information available on the behavior of oil and gas mixtures flowing through reservoir formations. This makes it impossible to predetermine the optimum operating condi-tions for flowing wells. A differential pressure must exist in the reservoir in order to induce flow toward the well. It is a well established fact that with homogeneous fluids the relation of pressure drop to linear distance traveled is a straight-line function as long as the flow is viscous. However, in regard to gas-saturated oils, a number of investigators1,3,4 have reported that the flow characteristics are materially altered as some of the lighter hydrocarbons are liberated from the oil to form gas while the fluid passes through the reservoir. Most of the work done has been concerned primarily with steady-state flow of liquid-gas mixtures. Cloud1 has studied the effects of saturating crude petroleum oils with various gases, together with the resultant pressure gradients under steady flow conditions, noting that unsaturated oils flowed faster and yet maintained lower pressure gradients than saturated oils.

Jan 1, 1938

By R. E. Reed, C. J. McHargue

Single crystals of aluminurn were reduced 90 pct in diameter by extrusion at 296" and 77°K. The resultant double fiber texture had a strong (111) component with a weak (001) component. The relative anzounts of these components varied with starting orientation. Decreasing the Lemperatuve of defovtnation increased the amount of (001) texture component in crystals with inilia1 orientations near (111). The starting orientation and temperature of deformation strongly affected the morphology of the (001) component. The effects of orientation and Lemperatuve upon the distribution of the (001 ) texture component in extruded aluminum single crystals were rationalized on the basis of deformation band formation and interaction. MANY papers since the early 1920s have discussed the occurrence of the double fiber texture (111) + (001) in wires and rods of deformed fcc metals. Aside from the reporting of experimental results for the various metals under a variety of fabrication conditions, emphasis has been placed on two related problems. One problem deals with the prediction of ideal end orientations based on the glide systems and flow directions. The other problem seeks the reason why different amounts of each component may be produced by the same fabrication schedule for metals apparently having the same deformation systems. Some of the difficulties in developing a satisfactory explanation have their origin in the experiments themselves. One mistake has often been the assumption of an initially randomly oriented specimen or complete ignorance of effects of starting orientation. Recent studies by Grewen and Wassermann,1 Cullity and co-workers,2' and McHargue4 have shown that the initial orientation may be the most important factor in determining the final orientation. Hence only limited comparisons of data from different studies can be made unless all conditions of the initial material are specified. Another question has been the nature of the (001) component. Hibbards suggested that any (001) present was the result of re crystallization during fabrication. Although Fleischer6 found no (001) texture in aluminum swaged at room temperature, and Dayal 7 found that component to disappear at very high reductions, a double fiber texture has usually been reported for aluminum. Vandermeer and McHargue showed that, while some (001) in aluminum may be the result of recrystallization, much of this component has its origin in the deformation process. Ahlborn and Wassermanng found the (001) component in silver deformed at low temperature not to be the product of recrystallization.

Jan 1, 1968

[MUNOZ, P.: New Oil Fields in Trinidad, M27, 311 MUNRO, C. H., biography, M84, 354 MUNROE, H. S., biography, M83, 277 Muntz metal (See also 60:40 Brass): corrosion. See Corrosion of Metals. fatigue and corrosion-fatigue, 78, 597 heat-treated: cleavage structure, 83, 498, 505 grain growth, abnormal, 83, 503, 505 machinability, 99, 323 stress-corrosion cracking, 89, 249. 266 MURAKAMI, T.: iron-silicon diagram, 80, 253, 255 MURDOCH, J. A. W., biography, M28, 157 MURDOCK, W. J.: Discussion on Adaptability of Various Coals as Generator Fuel in Manufacture of Water Gas 78, 561, 565, 566, 568 MURPHY. D. W. AND CHIPMAN, J.: Solubility of Nitrogen in Liquid Iron (T.P. 591) 116, 179. Abs., YB35, 33; M35, 114 MURPHY, L. J.: Relative Advantages and Costa of Electric Power in Lease Operations 77, 219]

Jan 1, 1936

By T. M. Geffen, F. F. Craig

Laboratory model flow tests have been made to simulate field conditions of partial pressure rnaintenance by dispersed gas drive on rocks having sandstone-type porosity. In this production method there is a significant saturation gradient between injection and production wells. A means of calculating relative permeability characteristics. from partial pressure rnaintenance flow tests has been developed. This method takes into account the saturation gradient. These kg/ko characteristics are identical to those for solution and external gas drives. This method of calculation, which has been proved experimentally, has limitations; however, it is valid for cases likely to be encountered in field prediction of partial pressure maintenance performance. The production performance of a hypothetical reservoir has been calculated for several different injection programs, involving both full and partial pressure maintenance. Results indicate that the maxinum oil recovery by these gas injection programs is obtained by full pressure mainte- nance at the original bubble point. Correspondingly lower oil recoveries are obtained by postponing gas injection and/or by reducing the degree of pressure maintenance. INTRODUCTION Dispersed gas injection is an important method of recovering additional oil beyond that obtainable by pressure depletion alone. The injected gas acts as a source of additional energy to displace oil from the rock formation as well as to retard oil shrinkage in the reservoir. In practice, gas injection is usually started after the reservoir pressure has fallen below the original bubble point. For various reasons sufficient gas is generally not injected to completely maintain the pressure in the reservoir. So, injecting gas at a declining reservoir pressure results in a combined external and solution gas drive. These two oil displacement processes are characterized by different gross saturation distributions in the reservoir. The external gas drive, like all frontal drive processes, inherently results in an oil saturation which increases from the injection wells to the producing wells. In the solution gas drive there is essentially a uniform oil saturation throughout the reservoir, provided the field is being depleted uniformly. It has been customary to predict oil recovery performance under partial pressure maintenance by a method which does not take into account the saturation gradient1. It has been shown2 that neglecting the presence of a saturation gradient can cause considerable error. It is the purpose of this paper to develop and present an improved method of predicting partial pressure maintenance performance of reservoirs including, where necessary. the effects of well arrangement. From the laboratory standpoint, this problem involves the measurement of the basic flow behavior (relative permeability characteristics) under partial pressure maintenance conditions. Recent research- as shown that for rocks having sandstone-type porosity, the relative permeability characteristics are identical for solution gas drive and complete pressure maintenance external gas drives. Since both solution and external drives have the same basic flow behavior, it was speculated that partial pressure maintenance, being a combination of the two, would also

Jan 1, 1957

By Stephen E. Merritt, T. Carl Shelton

Surveying and mapping are used to locate and visually portray objects, lines, or areas in relation to a reference point or line. The actual making of the measurements to locate the objects and points falls under surveying while mapping is concerned with putting the survey information into a graphical form. Generally, the type or class of proposed survey depends on the precision required. Some surveys may need only approximate measurements which can be obtained by simply pacing or by using an ordinary measuring tape; others may require much accuracy, thus calling for the use of an engineer's transit or theodolite along with a graduated steel tape for horizontal measurements, or a level and a graduated rod for measuring vertical distances. Mapping is likewise dependent on accuracy requirements. For example, a general layout showing the relative position of surface facilities may not call for a large scale of dimension or great precision whereas for detailed work, a large scale plus care in plotting points and drawing lines and curves are important factors. SURVEYING METHODS There are many kinds or types of surveying methods. Some examples include: land surveying for determining boundaries of land areas ; route surveying for locating roads, highways, right-of-ways, and haulways; city surveying for laying out lots, streets, and alleys ; and mining surveying for projecting mine openings and locating mining operations. There are other types of surveying than those named, but in general, the type of method to be used will depend on the purpose for which the survey is to be made.

Jan 1, 1973

By Michel Daghert, Michel David

In the exploitation of large porphyry type deposits where a cut-off has to be applied and where "internal waste" exists, planning people ask the geologist for the estimated grade of small blocks. Comparison with actual production figures and blast hole assays shows that any kind of weighted average of neighboring DDH (diamond drill hole) samples provides an excessingly smooth picture of reality, resulting most of the time in overevaluation of tons of ore. Solutions based on examination of Past production data exist14 but it would be necessary to have a solution which can be applied before production starts as the preceeding problem also results in an overestimation of the total reserves, often by as much as 20%, thus changing the mine life accordingly and destroying any "optimum planning" which could have been done. The proposed alternative is to forecast the grade distribution of small blocks in a larger block, sufficiently well documented. Several Possible ways to estimate these distributions are reviewed and emphasis is placed on recently developed methods (source G. Matheron) where the coefficients of the orthogonal polynomial series expansion of the distribution of any size of block are directly estimated by kriging. The efficiency of the technique is tested on a level of the Cyprus Pima open pit where the predicted recovery is compared to actual production figures.

Jan 1, 1980

By R. C. Allen

ABOUT four years ago the writer proposed a revision of the correlation of the Huronian formations in Michigan, and noted the bearing of the question on the correlations of the Huronian rocks in Wisconsin and Minnesota.1 Dr. C. K. Leith opposed this revision and argued for the retention of the correlations of the United States Geological Survey, published in 1911,2 for which he and Dr. Van Hise were mainly responsible. As late as June, 1917, Harder and Johnson, following Leith, thought it "premature to change radically a correlation based on years of careful field work."3 The work of Wolff on the Mesabi and Cuyuna Ranges, of Hotchkiss on the Gogebic Range (unpublished), and of the writer and assistants on the Michigan ranges, together with data developed by exploratory and mining operations, has introduced so many pew facts not recognized in the scheme of the U. S. Geological Survey that the correlations of 1911 must be considered, in some important respects, obsolete. Indeed new data are accumulating so rapidly that any classification, which for the moment may seem best to explain the facts, is almost immediately modified or refined by further observations. The problem of Huronian correlations is difficult, but interesting and important. With the aid of fossils, stratigraphers of the post-Algonkian formations have been able to show that slight disconformities may separate strata of vastly different ages, and that within physically conformable strata may be concealed a hiatus of great magnitude. In the non-fossiliferous Huronian group, minor physical breaks in the strata are

Jan 9, 1919

By Samuel Gibson Frantz, G. W. Jarman

The purpose of this paper is to relate briefly the development of magnetic separation and its extension from the separation of iron into its present use in the nonmetallic field, to suggest possible future extensions of its field of usefulness and its possible cooperation with other separating methods. The engineering design of separating machines, and statistics as to the number of machines in operation, types, their location and production are outside the scope of this paper. Specific data will be given, however, on certain selected applications. A large part of human endeavor consists in separating one thing from another; the good from the bad, the desired from the undesired. In fact, a philosopher might plausibly claim that separating things into categories and choosing between them is the object of thought itself. In dealing with matter, separation is nowhere more inherently necessary to attain our objects than in mining and metallurgy. Both our desire and our ability to make separations are results of the physical differences between things. Gross separations such as removing ore from worthless rock or coal from slate are usually made visually and depend upon form and color, which are physical properties. When the desired and the undesired things are intimately mixed, however, it becomes impractical to select visually even if the individual particles are readily recognizable to the eye, and some automatic way of making the particles separate themselves on the basis of their own inherent differences in physical properties must be resorted to. Some of the physical properties which have been used as a basis of separation are: color, shape, hardness, size, density, elasticity, surface propertics (surface tension in contact with liquids, etc.), electrical conductivity, dielectric constant, and magnetic susceptibility. Differences in these properties are used in the following methods of separation: color sorting, sifting, settlement in air and in liquids, float-sink methods, flotation, electrostatic and magnetic separation.

Jan 1, 1932

By H. J. Fisher, J. L. Walter

Two types of Si-Fe columnar ingots with preferred crystal orientation have been produced: a) ingots with (0011 directions of the crystals parallel to the longitudinal ingot axis and b) seeded ingots in which all crystals have the (100) [001]orientation with respect to the sides of the ingot. Measurements of freezing rates and temperature gradients indicated that columnar freezing occurred as long as the temperature gradient ahead of the solidification front was greater than zero. THE development of preferred orientations or textures in wrought metals may be influenced by the presence of a preferred crystal orientation in the ingot from which the product was made. The deliberate introduction of preferred orientation in the ingot for the express purpose of producing a particular preferred orientation in the wrought product has not, to the authors' knowledge, been reported in the literature.* This report describes the prepara- tion of ingots of 3 1/4 pct Si-Fe in which preferred orientations near (100) [001] were produced. These ingots were subsequently rolled to strip, 0.012 in. thick, to provide a sufficient quantity of polycrystal-line sheet having the (100) [001] orientation or "cube-texture" to evaluate the magnetic properties. The properties; and test results showing the advantage of the cube-textured Si-Fe magnetic sheet over magnetic sheel having the (110) [001] texture or "Goss" texture have been reported elsewhere.' The rolling and recrystallization textures of single crystals of silicon-iron having orientations near (100) [001] have been studied by Walter and Hibbard.2 They found that if the crystal has an original orientation such that the (100) plane is within 30 deg of the rolling plane, the recrystallization orientation will approach (100) [001]. If the (110) plane is nearly parallel to the rolling plane,

Jan 1, 1962

By Wilbur I. Duvall, James F. Devine

7.4-1. Introduction. Ever since explosives were discovered and developed for mining purposes, there has existed the problem of determining what effect the air and ground vibrations resulting from blasting have on structures of various types. This problem is especially acute for surface operations such as open pit mines, quarries, and construction projects that are in the proximity of residential districts, scientific laboratories, or other vibration-sensitive structures. Because the general public is directly involved in the blasting vibration problem, it has been of major concern to local, state, and federal governments, as well as to mining and construction companies, explosive manufacturers, insurance companies, and scientific investigators. Consequently, many investigations have been conducted, both in this country and abroad, on the effects of air and ground vibration on residential and other structures. E. H. Rockwell made some of the first studies in this country on the vibrations produced by blasting and the effect that these vibrations have on structures (18). In his publications, he stressed the need for measuring the vibrations from quarry blasting in order to establish the level of vibration as a function of charge size and distance. The concept of a damage criterion for structures was developed shortly thereafter, and a displacement of less than 0.03 in. was considered safe. During the period from 1939-1942, the Bureau of Mines conducted an extensive investigation on the problem of seismic effects of quarry blasting. This work, summarized in Bulletin 442 (20) was the first major effort for establishing damage criteria for residential structures based on experimental data. An acceleration of less than 0.1 g was considered safe, 0.1 to 1.0 g was caution, and greater than 1.0 g was damage. This work

Jan 1, 1968

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

By E. K. C. Williams, Nathaniel Arbiter

INTRODUCTION The surface processes involved in preparing ores for flotation and for operations depending on their flocculation/dispersion characteristics * vary widely in agitation dependence. Most of the reagents used for these purposes are added to grinding circuits, pump sumps, launders, or directly to flotation cells with the turbulent flow conditions usually adequate both for mixing reagents and for surface reactions without special conditioners. However, some reagent systems do require specific control of agitation intensities and reaction times, the more important of these being the following: 1. Activation of ZnS with CuSO4. With the usual conditions pH about 10, with collector added with the CuSO4, Cu 2+ is almost completely precipitated as basic compounds and as collector salt. As a result the levels of reagent in solution are extremely low which probably accounts for the need for separate conditioning. The agitation intensities are at about the 0.01 HP/ton level.** 2. Flocculation with natural or synthetic polymers. In this case the agitation problem is two-fold; first, to insure adequate initial mixing of the viscous stock solution of the

Jan 1, 1980

By Douglas R. Cook

The discovery of the gold deposits of the Jerritt Canyon district, with proven recoverable reserves in excess of 67.6 Mg (2.4 million oz) of gold, has contributed greatly to the tremendous resurgence in exploration for disseminated gold deposits in Nevada and throughout the west. The Jerritt Canyon project, including the Bell mine, is a 70130 joint venture between Freeport Gold Co. and FMC Gold Corp., both of which are wholly owned affiliates of the respective parent companies, Freeport-McMoRan Inc. and FMC Corp. The Jerritt Canyon district is located in the center of the Independence Mountains in north-central Elko County, Nevada, approximately 48 km (30 miles) northeast of the Carlin gold mine and 68 km (42 miles) north of Elko. Although the discovery of a commercial gold mine at Jerritt resulted from Freeport's exploration activities, the initial identification of a gold prospect in this area was a consequence of a program by FMC in the search for antimony. Their program was, in part, based on data in the Nevada Bureau of Mines Bulletin 61, "Antimony Deposits in Nevada." Work on the property began in 197 1 with geologic mapping followed by sampling and geochemical analyses. FMC geologists, including Robert Hawkins, Russell Hayden, and Hal Hurst recognized the striking similarity of the area to the geologic environment of Newmont's nearby Carlin gold deposit and soon focused on the gold potential. Increases in the price of gold served to stimulate interest and support for the exploration program. Geochemical samples were collected and analyzed for gold and trace elements usually associated with gold. A strong gold anomaly was found on the North Fork of Jerritt Canyon, which was called the Alchem anomaly. Drill-testing of this anomaly in 1973 revealed significant grades and thicknesses of gold mineralization in the lower portion of the Roberts Mountain formation. This initial discovery and subsequent close-spaced drilling proved the existence of several small pods of low-grade, gold-bearing material which cropped out at their up-dip edges, causing the surface anomaly. The mineralization was very encouraging, but was not, by itself, of economic importance from the standpoint of either grade or tonnage. Freeport Exploration Co. established a district office in Reno in late 1974 with responsibilities for exploration of hard minerals in the Basin and Range Province. Emphasis of the program was directed to the discovery of precious metal deposits. Enfield Bell, as District Manager for this new office, was particularly interested in the Independence Mountains and when the opportunity for a joint venture with FMC became available in 1976, it was aggressively pursued. Enfield Bell and David Stevens evaluated the FMC data and with the support of management formulated a bid in competition with 23 other companies. Freeport was selected by FMC as partner and a joint venture agreement was successfully negotiated. In mid-summer of 1976, Freeport Exploration Co. began an expanded program of detailed mapping and geochemical sampling under the direction of Bell and Stevens that led to new interpretations of the structural and alteration patterns. Hawkins' contribution during this period must be recognized since he not only was one of the original geologists assigned to the antimony and subsequently the gold investigations, but shortly after the start of the joint venture exploration, he was hired by Freeport Exploration Co. as the project geologist for the venture. Hawkins had studied the central Independence Mountains for his thesis and his understanding of the regional geology provided an excellent background for the continued exploration of the gold de- posits. His interpretation of the structure in the vicinity of the Alchem anomaly was of significant help in the Freeport exploration program. Drilling, based on this new under- standing of the geology, revealed the edge of the Marlboro Canyon ore body, which is now being exploited in the Bell mine. Although a classic bullseye geochemical target led to the discovery of the Alchem mineralization, the bulk of the reserves known today in the Marlboro Canyon area lay

Jan 1, 1985