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By D. V. Carter, Dan C. Williams, John R. Coombs

Exploration was active in East and East Central Texas during 1944. Ten oil fields were discovered during the year, of which four show promise of development. The discovery wells of the Sand Flat and Tyler, South fields were drilled to a depth greater than 10,000 ft., and the latter field now produces from the Pettit at a depth of 9890 ft. The Sand Flat well was plugged back to the Paluxy. The other two fields are Glen Rose producers near 8000 ft. The Pickton field produces from the Bacon Lime and Winnsboro from the Rodessa section. The Eylau field, Bowie County, was significant as the first Smackover production in Texas. Magnolia drilled a test in the Concord field, which topped salt. The most extensive and significant development in the district was the Carthage gas-condensate field. It expanded from the 8000 acres of last year to an estimated 190,000 acres, or about 300 sq. miles, and is not defined as yet. The first oil production in the Carthage area was made from the Travis Peak in 1944 in the Rogers Lacy's Cameron Lumber Company well No. I, on the northwestern side of the field. The New Hope field, Franklin County, scored the largest number of completions during 1944 with 24, bringing its total number of wells to 27. Two more pays were opened and produced as dual completions with the older horizons. The Manziel field, Wood County, had 19 new wells added during the year, for a total of 29, while the Pittsburgh field, Camp County, reached a total of 23 wells by completing 14 new ones. Material shortages and drilling restrictions dropped the total number of producing wells completed in the district from 171 during 1943 to 141 for 1944. Abandonments increased from 531 during 1943 to 609 for 1944. Of this number, 479 were in the East Texas field. Subsidy payments had very little effect in the district and it was mostly a few of the old fault-line fields that had any wells to fall within the requirements for subsidy payments. The prices of crude oil remained constant in the district except for increases as a result of subsidy payments. Production and Probation Wartime demands called for increased allowables for many fields, consequently the condensate and oil production for 1944 increased to 190,016,180, which is up 6.9 per cent over 1943. The East Texas field, of course, remained the principal producer of the district, accounting for 134,768'499 bbl. during the year, or 71 per cent of the district total production of condensate and oil. The field topped its own 1943 production by 4.8 per cent and became the first field in the world to produce 2 billion barrels of oil. The Hawkins field remained the second largest oil producer in the district, with 13,317,088 bbl. for the year, a drop of 6.8 per cent from 1943, while Van field was third with 11,635,708 bbl. The

Jan 1, 1945

By J. S. Aronofsky, H. J. Ramey

Potentiometric model studies of the five-spot water flood to determine the influence of mobility ratio upon injection or production histories are described. The results suggest a method for the correlation of data from field pilot tests for the estimation of an effective mobility ratio and its effect upon field water floods. The effect of the well spacing-to-well radius ratio upon production histories is presented. A method of accounting for this factor is suggested. The influence of injection (or production) rates and injection and production well pressures upon production histories is shown. The five-spot well pattern was investigated for water-to-oil mobility ratios of 0.1 to infinity. INTRODUCTION It has been well established that mobility ratio has an important effect upon flood patterns.1,2,3,4,5 It should be equally apparent that injection and production histories must also be influenced by mobility ratio. However, none of the articles referred to above mention the importance of being able to predict the effect of well pressures (or injection rates) during the entire time history of a waterflood operation. A complete description of production histories (the terms "injection" and "production" are synonymous for the steady-state model under consideration) would provide values for well pressures and interface positions at any time for a specified injection rate. conversely, if the waterflood problem is specified in terms of a constant injection well pressure, then it would be desirable to know the injection rate and interface positions at any time. This paper describes the results of potentiometric model studies which were used to analyze the influence of mobility ratio on injection or production histories. A method is presented for calculating production histories over a range of ratios of well spacing-to-well radius. The basic method described in this paper to evaluate production histories is to: (1) determine interface position as given in Ref. 1, and (2) measure electrical current and voltage drop for each interface position. It should be mentioned that the current state of knowledge on flood patterns as affected by mobility ratio shows that significant discrepancies exist between the results of various investigators2,3,4,5. It is beyond the scope of this paper to discuss the reasons for such discrepancies. However, the method of determining production histories presented in this paper could be applied to any of the swept-area patterns presented in the literature. All results given in this paper are based on a set of swept areas obtained by the potentiometric method. Potentiometric analyzer technique is adequately described in the literature, but the basic assumptions involved in work of this nature bear repetition. It is assumed that: 1. A distinct oil-water interface exists in the reservoir; only water is mobile in the region behind the interface (water zone) and only oil is mobile in the region ahead of the interface (oil zone). 2. There is a fixed mobility value, (k/µ) w associated

Jan 1, 1957

By J. S. Bryner

In the study of metallographic specimens in the electron microscope, there is need for a method of locating the same field in both the light microscope and the electron microscope. This need arises chiefly from the fact that in the electron microscope the magnification and degree of resolution are so much higher, and the field so much smaller than in the light rnicroscope that it is often difficult, if not impossible, to identify positively what is being observed. The difficulty is increased by the fact that, because a transparent film replica of the metal surface must be used in the electron microscope, micro-constituents can be identified not by their color but only by their texture and contours. For these reasons it is desirable to obtain a series of photographs showing the same field in both microscopes in order that the appearance of common microstructures and micro-constituents in the electron microscope may be identified and catalogued for future reference. The need for a method of locating the same field in both microscopes arises also when it becomes desirable to enlarge in the electron microscope for more detailed study a particular interesting structure observed in the light microscope. Using the standard polystyrene-silicalJ replica technique, in which the silica film replica is fished from the ethyl bromide on a 1/8 in. diam zoo-mesh specimen screen, the possibilities of locating a particular area on the film in the electron microscope are rather remote. The desired structure may be obscured by the wires of the specimen screen or unrecognizable at the high magnification. A solution to the problem would be provided if a specially designed specimen screen, containing an opening which could be absolutely identified and quickly located in the electron microscope, could be fastened to the silica film replica in such a position that the desired field on the specimen would be located at the identifiable opening in the specimen screen. The design for such a specimen screen, a method for producing it, and a technique for fastening it to the silica film replica are described below. Description OF Method The Specimen Screen A simple design for a specimen screen containing an opening easy to identify and locate in the electron microscope is one with two lines of openings at right angles in the form of a cross. Such a screen is shown in Fig I. The opening at the center of the cross is identified easily and can be located quickly in the light microscope and in the objective image of the electron microscope. The specially designed specimen screens for this work were produced in quantity by electroforming. On both sides of a polished strip of copper I X 3 X 1/8 in., twenty patterns of the cross of openings were punched with a diamond point micro-hardness tester, using a load of magnitude

Jan 1, 1949

By J. S. Bryner

INTRODUCTION IN the study of metallographic specimens in the electron microscope, there is need for a method of locating the same field in both the light microscope and the electron microscope. This need arises chiefly from the fact that in the electron microscope the magnification and degree of resolution are so much higher, and the field so much smaller than in the light microscope that it is often difficult, if not impossible, to identify positively what is being observed. The difficulty is increased by the fact that, because a transparent film replica of the metal surface must be used in the electron microscope, micro-constituents can be identified not by their color but only by their texture and contours. For these reasons it is desirable to obtain a series of photographs showing the same field in both microscopes in order that the appearance of common microstructures and micro-constituents in the electron microscope may be identified and catalogued for future reference. The need for a method of locating the same field in both microscopes arises also when it becomes desirable to enlarge in the electron microscope for more detailed study a particular interesting structure observed in the light microscope. Using the standard polystyrene-silica1,2 replica technique, in which the silica film replica is fished from the ethyl bromide on a 1/3 in. diam 200-mesh specimen screen, the possibilities of locating a particular area on the film in the electron microscope are rather remote. The desired structure may be obscured by the wires of the specimen screen or unrecognizable at the high magnification. A solution to the problem would be provided if a specially designed specimen screen, containing an opening which could be absolutely identified and quickly located in the electron microscope, could be fastened to the silica film replica in such a position that the desired field on the specimen would be located at the identifiable opening in the specimen screen. The design for such a specimen screen, a method for producing it, and a technique for fastening it to the silica film replica are described below. DESCRIPTION OF METHOD The Specimen Screen A simple design for a specimen screen containing an opening easy to identify and locate in the electron microscope is one with two lines of openings at right angles in the form of a cross. Such a screen is shown in Fig I. The opening at the center of the cross is identified easily and can be located quickly in the light microscope and in the objective image of the electron microscope. The specially designed specimen screens for this work were produced in quantity by electroforming. On both sides of a polished strip of copper 1 X 3 X 1/8 in., twenty patterns of the cross of openings were punched with a diamond point micro-hardness tester, using a load of magnitude

Jan 1, 1948

By C. Dean Starr

The physical basis of the equation correlating electrical conductizlity and temperature coefficient of resistance of solid solution alloys has been inzlestzgated and the nature of the constants evaluated. It is shaun that the same form of correlation is valid irrespective of the magnitude of the temperature coefficient. However, the effect of therma1 expansion and change in resistivity with temberature nust be considered when the magnitude of the temperature coefficient of resistance is near zero. In a comprehensive literature survey conducted at the Armour Research Foundation in 1950, it was found that a linear relationship exists between the electrical conductivity, K, and the temperature coefficient of resistance, a, for solid solution alloys. This was expressed by the equation where B, a constant, depends on the solvent metal but not the solute. A continuing investigation by Hansen, Johnston, and Parks showed this equation was generally appropriate for Cu, Ag, Au, Pd, Pt, and Co base binary solid solution alloys as well as for many ternary alloys of copper over a range of conductivities and temperature coefficient of resistances from 0.02 to 0.60 reciprocal pohm cm and-0.00015to0.004Q per 0 per "C respectively. Eq. [I] was not always valid for alloys that exhibited a change in state (magnetic to nonmagnetic) or for alloys that had a temperature coefficient of resistance near or below zero. For example, in nickel alloys, a simple linear curve as predicted by Eq. [l] was not obtained when the conductivity was plotted against the temperature coefficient of resistance. Hansen suggested that deviations observed were caused by transitions from a ferromagnetic to a nonmagnetic state. Subsequent and more extensive data by ronin on Ni-Mn alloys confirmed Hansen's postulate. While both states independently showed a linear relationship between K and a, the value of B was different for the two states. In some copper and gold base alloys, as well as the platinum and palladium alloys investigated by Hansen, the conductivity did not extrapolate to zero at zero a as demanded by Eq. [I]. This deviation can be readily corrected by simply adding a constant to Eq. [I.] whence Eq. [2] shows the K decreases as a decreases but that K has a positive value when a = 0 which is observed for commercial solid solution alloys as well as the experimental alloys tested by Hansen. While other methods of correlation of electrical properties have been made such as the one by Starr and Wang3 who found a linear relationship between resistivity and temperature coefficient of resistance for Ni-Cr-Al-Cu alloys, the data, in general, can also be correlated by a form of Eq. [2]. Thus, Hansen's empirical equation has considerable merit. The objective of this paper is to determine the physical basis for this equation and to examine the region near zero a in more detail. ELECTRICAL CONDUCTIVITY VS TEMPERATURE COEFFICIENT OF FU3SISTANCE The resistance of a metal or alloy is defined as

Jan 1, 1963

By John K. Gustafson

The title of my talk is "The Gold Miner and the Future of Gold." This title might just as accurately have been stated as "Gold and the Future of the Gold Miner." Since prehistoric times gold has been sought by mankind for its beauty and its unusual physical and chemical properties. Early in the dawn of civilization it became the ultimate unit of value and lubricated trade between peoples. For at least 6000 years, gold has been used to barter for other commodities. It has been prospected for, treasured, made into works of art and personal adornment, and from time to time has been the object of conquest. Because of its predominant role in recent centuries as a basis for money, economists began to think of it solely in these terms. Annoyed by the disciplinary pressure of gold on the money manager's desire to manipulate money, the famous economist, John Maynard Keynes, characterized it as a "barbaric relic of the past", a characterization repeated by William McChesney Martin, Jr., when he was head of the Federal Reserve Bank. Gold, however, has physical and chemical properties that make it one of the most useful metals in the modern world.' It is the most ductile metal known. An ounce of gold, for example, can be drawn into a continuous wire over 35 miles long. It also is so malleable that an ounce of gold can be beaten into films ten one-millionths of an inch thick sufficient to cover 68 sq ft of surface. It has a density of 19.3 and is so heavy that 1 cu ft of gold weighs more than half a ton. Gold is nonmagnetic and has a high electric conductivity, only slightly less than silver and copper. Gold is so inert to all the chemicals found in nature that gold coins and jewelry buried beneath the soil or at the bottom of the sea for thousands of years appear to be as bright and perfect as when they were first immersed. Finally, gold has an extremely high reflectivity both to light and infrared rays. Because of these qualities, in addition to its rare beauty, industrial and artistic uses of gold have been growing rapidly. On a world basis, a recent study estimated that in 1960 about 750 tons of gold were used for fabrication, and that the amount had grown to about 1296 tons in 1968. My objective in this talk is to discuss with you the present and future supply of and demand for gold on a worldwide basis and the effect these forces are likely to have on the price the miner can expect to receive for the gold he produces. This is a highly controversial and risky subject to discuss before any audience. Nevertheless, it is a subject that I live with constantly as Chairman of the

Jan 1, 1972

By J. J. Gilman

THEORIES of fracture in metals have been based primarily on the dependence of fracture strength on grain size. This dependence was first observed by Masing and Polanyi.l These workers, as well as 0rowan12 and Davidenkov and Wittman,' thought the grain size could be equated with the crack size in the Griffith condition for crack propagation.4 In this way they could account for the observed proportionality between fracture stress and the reciprocal square root of the grain size. The chief results of recent investigations of the fracture strength of polycrystals are summarized in Fig. 1. Low for iron,5 Petch for iron,' Greenwood and Quarrel for zinc, Petch and Zein for zinc,' and Hauser, Landon, and Dorn for magnesium'' have all found that the fracture stress of a polycrystal is proportional to the reciprocal square root of the grain size. Also, they find that, for large grain sizes, the fracture stress lies near the extrapolation of the yield-stress curve determined at small grain sizes; where measurable plastic strain precedes fracture. Low9 has gone a step further and shown that, in Range 1, the fracture stress in tension is almost identical to the yield stress in compression for a given grain size. Homes and Gouzou, 10 and Low also have shown that, in Range 2 of Fig. 1, microcracks form when the yield stress is reached, but they do not cause failure until the stress reaches a much higher value. The fact that yielding always precedes fracture suggests that fracture is induced by plastic flow. A mechanism by which this might occur was first proposed by Zener.11 He pointed out that blocked dislocations would cause stress concentrations which might cause fracture. The blocking would be caused by grain boundaries. This idea has been developed by Eshelby, Frank, and Nabarro,12 by Koehler,13 and by Stroh.14 By means of etchpits blocked dislocations have been observed in brass by Jacquet,15 in zinc by Gilman,16 and in lithium fluoride by Gilman and johnston. The blocked-dislocation theory and the experiments that bear on it have been summarized by Mott.18 One of the strong points of the blocked-dislocation theory is that it can explain the grain-size dependence of the fracture stress in a natural way. However, Low9 has pointed out that the theory is not satisfying when it is considered quantitatively. Gilman10 also has criticized the theory and presented an alternative interpretation of the relation between fracture stress and grain size. Since the blocked-dislocation theory is not the only theory that can explain in the grain-size effect, it is necessary to find other evidence either to support or deny it. In this investigation the following points were studied: 1) If blocked dislocations normally cause fracture, then the fracture stress ought to be very high in the absence of plastic glide. Is it? 2) If dislocations must be blocked in order for metals to fracture, then certain types of grain

Jan 1, 1959

By Thomas C. Wilder

The activities of both components and the partial and integral molar thermodynamic properties of mixing for the liquid Al-Ge system at 1200°K and for the gertnanium-rich Al-Ge liquidus have been determined from data for eighteen alloys of compositions in the range 0.0593 < 0.880 using the reuersible gal-vanic. cell in the temperature interval 9320 to 1258°K. The liqui-dus compositions above 93 2 °K loere also ve determined by observing the discontinuities in the C us T plots for the high-melting alloys. This system shows moderate negative deviation from ideality throughout, the values for y° being 0.212 and 0.189 for aluminum and germanium, respectively, at 1200°K. Pavtial molar Properties of aluminum on the germanium-rich solidus and at infinite dilution in Ge(s) oboue 932°K were estimated from the foregozng measurements and the equlibrium data of previous investzgators. RECENT compilations of data1" have shown an increasing demand for knowledge of the thermodynamic properties of mixing of metallic alloy systems. In the case of binary-liquid systems where one of the components is a semiconductor this information is useful because, primarily, properties of the second (dopant) component on the liquidus, solidus, and at infinite dilution may be determined more accurately than from calculations based on the phase diagram. In this investigation a reversible galvanic cell was used to determine the chemical potential of aluminum in the two-phase region, liquid + [Ge], on the germanium-rich side of the A1-Ge system in the temperature range 932" to 1193°K. In addition, similar measurements for homogeneous liquid A1-Ge alloys for the entire composition range were obtained for the temperature interval 932" to 1258°K. The cell used was: The experimental technique and the treatment of the data were essentially the same as described earlier394 and are elaborated upon only briefly here. Each cell consisted of a liquid aluminum anode and three A1-Ge alloy cathodes of different composition which were held in Morganite alumina crucibles. The alloys were made up from aluminum and germanium weighed to the nearest 0.1 mg to a total weight of 5 to 10 g. Aluminum was a gift of Aluminum Co. of America and had a purity of 99.995+ pct. Germanium of transistor grade was a gift of Bell Telephone Laboratories. The four electrodes were contained in a larger alumina crucible which also held the prepurified fused chloride electrolyte. Contact to the electrodes was made by tantalum wire leads sheathed in alumina. The tantalum leads were centered in the electrodes by suitable positioning of an alumina radiation shield which fitted on the top of the - alulnina crucible. Two chrome l-alumel thermocouples, sheathed in quartz wells, completed the internal cell arrangement. The entire assembly was enclosed in an alumina tube, fitted with a water-cooled copper head so the system could be evacuated and then flushed with purified argon. *

Jan 1, 1967

By Dale R. Ralston, Roy E. Williams, Gerry V. Winter, George L. Bloomsburg

GENERAL STATEMENT Data frequently can be collected by several dif¬ferent methods. The method required for the nec¬essary precision for inflow prediction to mines should be selected and other methods avoided. Pre¬cision monitoring or measuring techniques fre¬quently require more time, expertise, and expense in their implementation that may not be justifiable. The temporal distribution of the data needs also may dictate the method used for data collection. Continuous recording devices may be required for time sensitive data whereas point measurements of other parameters may be adequate. Data needs will vary as the hydrologic investigation proceeds. In¬itial data needs may require only a qualitative col¬lection of data such as the areal distribution of precipitation. Subsequent data needs may require the measurement of ground water levels to the near¬est hundredth of a foot. Data requirements can be difficult to fulfill for ground water systems. This is particularly true for anisotropic, heterogeneous hydrostratigraphic units since the hydrogeologic parameters vary both ver¬tically and areally. Techniques exist for determining the storage characteristics of both unconfined and confined hydrostratigraphic units but these pro¬cedures require the installation of multiple wells in the same unit which may be impractical. Specific tests are discussed subsequently that permit the determination of vertical hydraulic conductivity. Data collected from field procedures or tests are generally preferred to laboratory derived data. This is especially true for hydrogeologic parameters such as hydraulic conductivity. SURFACE WATER SYSTEMS Precipitation Precipitation data can be collected from sources that maintain a historical record. The US Depart¬ment of Commerce, National Oceanic and Atmos¬pheric Administration (NOAA), maintains weather observation stations across the country. Such a sta¬tion frequently can be found near a proposed mine site but the type of weather data collected varies from station to station. Fortunately, precipitation data are collected ubiquitously. The data collected by NOAA can be purchased for the area of interest in the form of monthly and annual tabulations. Private weather stations constitute a second source of precipitation data. Existing data usually are analyzed by one of three methods. The station average method merely sums the depth of precipitation at each station and divides the sum by the number of stations as fol¬lows: [ ] where Pavg is the average precipitation (L), P, is the depth of precipitation at station i (L), and N is the total number of stations. This method is applicable where there are a relatively large number of stations uniformly distributed across the area (Hjelnfelt and Cassidy, 1975, pp. 71-72). The second method, called the Thiessen poly¬gon method, weights the precipitation at each sta¬tion in direct proportion to the area it represents without consideration of topography. The stations are plotted on a map and perpendicular bisectors are drawn on the lines connecting the stations. The polygons formed by these bisectors constitute the area that the precipitation for that station repre¬sents. The overall precipitation can be calculated with the following equation:

Jan 1, 1986

23.1-SOURCE, POWER-SYSTEM ELEMENTS A. J. T HUM Basic considerations in providing power for mine production and collateral operations are: 1. Mining operations of any size normally use electric motors for driving all equipment except mobile service units. 2. The electricity for power may be purchased or self-generated, depending on the location, size and specific operating circumstances of the individual property. 3. The major elements of the power system will be the source, either an incoming transmission line from a utility in the case of purchased power or the power plant if self-generated. Energy for the power plant may be water, hydrocarbon fuels, waste heat or nuclear, which will govern the type of prime mover selected. 4. The electricity normally is generated in the form of alternating current and must be distributed to the points of usage. This usually requires a primary substation for transformation to suitable voltages and secondary substations at points of usage throughout the operations, The power is delivered from the primary to the secondary substations over transmission lines or cables, depending on distances, voltages and local conditions. 5. At the points of use, there will be starting and protective devices for each motor. In some instances, direct current will be needed and rectifiers of various types can be used to provide it. 6. The entire electrical system requires suitable switching and protective devices to prevent damage to the equipment in case of power failues or faults; also, in most cases, sufficient metering to establish the demand and amount of electrical energy consumed. 23.2-PURCHASED POWER A. J. THULI 1. Where public-utility or government-generated power is available, it usually is advantageous for the mine owner to purchase rather than generate. Purchased power generally will be cheaper and more reliable than operating a small generating plant except in some cases where waste heat is available as the source of energy and can be used to supply all or a portion of the power requirements. 2. If it is decided to purchase power, the owner usually must participate in the cost of constructing the connecting line from the closest existing utility line to his point of usage. If the connected load is less than 1,000 lip, it probably is best to let the utility provide the primary substation. For larger connected loads the owner can obtain a more favorable "primary voltage" rate if he provides the primary substation to receive the incoming power and transform it to the distributing and usage voltages. 3. The cost of purchased power usually is made up of a demand charge, deter¬mined by the maximum amount of power the customer takes during any 15-min period throughout a month, and a graduated energy charge for the kilowatt-hours consumed-that is, so much for the first block of energy based on the demand,

Jan 1, 1973

By John W. Brauns

18.1-RAILROAD JOHN W. BRAUNS Conventional railroad haulage can be employed at both open-pit or strip and underground mines-in the latter case, largely for transfer of ore from distant openings to processing plants, or processed material to loading points or docks, using standard hopper cars for bottom unloading or gondolas for rotary dumping. The major application, however, is in surface mining for moving ore and/or waste out of the pit to a crushing plant or dump. Consequently, the following will deal largely with this phase of railroad operation, though the conclusions apply equally, for the most part, to other rail-type surface haulage. In surface mining, trains consisting of a locomotive and gondola or side-dump cars suitable for loading by power shovels are used. Gondolas are restricted to hauling ore as a rotary dumper is required. Side-dump cars are more versatile, carrying both ore and waste, but because of their additional dumping mechanism they are likely to be more expensive to maintain.&apos; Also they weigh up to twice a flat-bottom car of the same capacity and. therefore, fewer" cars can be hauled per train. Standard-gage track is most commonly used. Track systems incorporate low-quality temporary track where moves are frequent and permanent high-quality track on main lines. Rail haulage can be used alone, or in combination with other surface haulage methods, thus permitting a selection best adapted to the peculiar requirements of each mining project. 18.1.1---GENERAL APPLICABILITY, CONTROLLING PHYSICAL CONDITIONS For handling rough rock, the shovel-train system is unexcelled.&apos; The ideal applica¬tion is in a large, but not excessively deep, open pit mine from which the coarsely blasted ore and waste must be transported over 3 mi. If. in addition, a high production rate is to he maintained, railroad haulage probably will afford a lower cost per ton transported. Grade must he relatively gentle-usually 3% uphill and 4% downhill. The greater the differences in elevation involved, the greater are the track grade space requirements; for example, a 3 c ramp out of a pit only 300 ft deep is almost 2 mi long. Main-line track locations should he selected carefully so that the number of moves during the life of the mining operation can he kept to a minimum. This applies both to the ore haulageway and that for waste. Such moves are not only expensive, but are difficult to execute without adversely affecting production rates. The large mine affords greater opportunities for judicious location of semipermanent trackage. Figs. 18-1 and 18-2 illustrate typical track layouts. The effect of terrain in considering railroad haulage is confined chiefly to the initial cost of the installation. Grade construction in mountainous territory is ap¬preciably more expensive. However, if that expense can be borne, the subsequent maintenance cost of trackage will not he much higher than in areas of low relief.

Jan 1, 1973

By M. J. Ferrante

Laboratory-scale tests were undertaken to examine several electrolytes for possible use in separating nickel and cobalt from products being prepared at Nicaro, Cuba. The most extensive work was done with nickel sulfate-ammonium fluoride, ammonium fluoride, ammonium sulfate, and nickel sulfate-boric acid electrolytes. All four electrolytes exhibited some selectivity for dissolving nickel carbonate from Nicaro basic carbonate used for regeneration. The nickel sulfate-ammonium fluoride electrolyte exhibited less selectivity for dissolving nickel carbonate from Nicaro basic carbonate than it did from synthetic mixtures. Ammonium fluoride leaching experiments showed that a low concentration and high temperature gave a good nickel extraction with C. P. reagents; however, this was not confirmed in tests using Nicaro basic carbonate. Electrolytic tests employing ammonium fluoride leach liquors gave no further separation, since approximately 90 percent of the cobalt was deposited at the cathode with the nickel.

Jan 1, 1958

Except for uranium search, conventional oil well logging techniques are relatively little-used in mining exploration. The main reasons for this are cost and an apparent lack of awareness of the potential use of the methods in the search for ore. However, relatively inexpensive portable units are currently available for performing the simpler electrical and radiometric logs in diamond drill holes.The emphasis in oil exploration logging programmes is largely on the estimation of porosity. In most mineral work, however, porosity is not very significant, and factors such as mineral conductivity and radioactivity assume an important role.The Bureau of Mineral Resources (BMR) during a programme to explore for uranium and associated base metals in the area east of Rum Jungle, N.T., carried out electrical and radiometric logging of diamond drill holes as a routine part of their investigations. Case histories are described in which the logs were used to aid in defining stratigraphic sequences and transgressive structures in base-metal prospects. Some surface geophysicalanomalies were explained by the logging: induced polarization and electromagnetic anomalies were related to black slate; and self-potential anomalies were related to oxidation of pyrite black slate, or apparent electrokineticeffects in the black slate. The logs provided an objective appraisal of the rock units penetrated and thereby helped to differentiate lithologies.Borehole logging, including newer techniques such as downhole analysis, could be done in geological and geophysical investigations in other areas for a relatively small cost with a considerable potential gain of information.

Jan 1, 1978

By J. H. Brophy, M. H. Kamdar, J. Wulff

A constitutional diagram for the Ta-W-Re alloy system is presented. Rhenium dissolves in the complete range of solid solutions between tungsten and tantalum up to 48 wt pct in tantalum &apos;to about 30 wt pct in tungsten. Intermediate x and u phases only are found. X-ray diffraction and fluorescence, metallography and melting-point measurements were employed. THE constitution diagram of ternary alloys of tungsten, tantalum, and rhenium for temperatures above 1000°C is reported in this paper. Alloys in this system rich in tantalum and tungsten are of interest for high-temperature applications, and those rich in rhenium for electronic applications. No ternary phase diagram appears to be available in the literature. The three-component binary diagrams have been previously established1-3 and the present ternary data are consistent with these. EXPERIMENTAL TECHNIQUES Commercially pure tantalum (99.7 pct), rhenium (99.99 pet), and tungsten (99.9 or 99.95 pct) powders were purchased from Fansteel Metallurgical Corp., Chase Brass and Copper Co., and Fansteel or Westinghouse Electric Corp., respectively. These powders were pressed without binder and arc-melted under helium. The preparatory and analytical techniques employed were identical to those used for the Ta-Re system investigation carried out in this laboratory.324 These included X-ray diffraction and metallographic phase identification, X-ray fluorescent and wet chemical analyses, solidus determinations and heat treatments in a resistance-heated tantalum-filament vacuum furnace. For microstructural examinations standard mechanical polishing techniques were used through diamond laps. Polished speciments of all compositions were etched by swabbing with 4 parts HI?, 4 parts HNO3, and 1 part H20. Since the microstruc-tures of alloys containing one or two phases closely resembled their counterparts in the respective binary systems, typical examples are omitted in this presentation. In all the alloys examined, it was possible to observe the number of phases present. Particularly when there were small amounts of one phase involved, it was possible to identify it only by a combined conclusion based on X-ray diffraction, position of an alloy in a composition series, and the phase rule. A total of 100 different alloy compositions was arc-melted and studied in the as-cast condition metallographically and by X-ray diffraction. Specimens of each of these compositions were heat-treated at 2680, 2530, and 2020°C for 1, 2, and 4 hr, respectively. Those which were treated at 2020 were given a preliminary homogenization treatment at 2500°C for 1 hr. Specimens of 25 alloys were heat-treated at 1200o C for 168 hr. Solidus temperature measurements were made by the detection of incipient melting in eighteen alloy compositions. The metallographic and X-ray diffraction results are summarized in Table I. Graphically, this information appears in the isothermal plots of Figs. 2 and 3. Within the accuracy of the experimental methods, two such plots are sufficient to locate these data, since the results for 1200°C were similar to 2020 and those at 2530 resembled 2680

Jan 1, 1962

By N. Arbiter

Introduction The theoretical analysis of tumbling mill energetics and performance has largely neglected mill dimensionality, and, in particular, the importance of the length/diameter (L/D) ratio. This is in spite of the fact that practice varies substantially: geographically, for semi-autogenous and autogenous mills, as between North America and South Africa/Scandinavia, and historically, for overflow ball mills, for which the L/D ratio has increased significantly from the earliest small mills to the largest mills currently. The present study is concerned primarily with the influence of the L/D ratio on the design and operation of overflow ball mills, on the occurrence of the overload phenomenon, and on the limits, if any, it may impose on mill capacities because of critical pulp axial velocity limits. It will be shown that the shape factor is of major importance in this area and that its adjustment to the extent that this is practical should remove the diameter limitations previously postulated for this mill type. Dimensionality in mill design Ball mill shape factors in the period prior to 1927 (Taggart, 1927) averaged 1.1/1 for 29 center discharge mills and 1.0/1 for 30 peripheral discharge mills. With the resumption of new plant construction after the 1930s depression, the Morenci concentrator continued the 1/1 ratio with its 3.1 x 3.1 m (10 x 10 ft) mills. The ratio was increased progressively from then on, reaching 1.6 and 1.8/1 for the largest overflow mills currently. As shown recently (Arbiter, 1989), this is in sharp contrast to autogenous and SAG mill shapes, for which the ratio averages 0.4 in North America. On the other hand, South African practice, starting at the turn of the century with autogenous mills having 4/1 ratios, moved toward 1/1 until recently, when a 2.5/ 1 ratio mill was installed. The reasons given for such divergent practice for mill shape factors are in some respects contradictory and generally inconclusive. The most complete discussion from a practical viewpoint (Dor and Bassarear, 1982) is limited to primary SAG and autogenous mills. Considerations of ball mill dimensionality have had a twofold direction. On the one hand, it has been argued that ball mill efficiencies should increase with increasing diameter and that the specific energy for a particular grind should be reduced accordingly. An inadvertent test of this idea at the Bougainville operation (Burns and Erskine, 1983) resulted in drastic underpowering, which led to failure to reach design capacity until additional mills were installed. This can be taken as strong evidence against any increase in efficiency with diameter. In another direction, it has been argued (Arbiter and Harris, 1982, 1983) that there is a limit to ball mill diameters because of the demonstrable limit to axial flow velocities evident in the overload phenomenon, which as a fact is incontrovertible. But that it places a limit on mill diameters overlooks the evidence given below that appropriate variation in the L/D ratio will permit major increases in diameter, limited only by constructional or economic factors. The present study was directed toward quantifying the overload phenomenon through examination of the influence of mill dimensionality variation and mill operating variables on its occurrence. It is shown that varying the operating conditions, specifically the load fraction and the fraction critical speed, can reduce the risk of overload for existing operations; while appropriate decreases in the L/D ratio can minimize the risk in the design of new circuits. Ball mill overload Ball mill overload is a consequence of the approach to a critical velocity with increasing feed rates or circulating loads. Although the effect has been known for over 50 years, there have been no previous attempts to quantify it. The following description of the ball mill as a flow system is the preliminary to a quantitative analysis: 1) In the absence of a ball load, axial flow of pulp through a mill resembles open channel flow, except for disturbances near the shell due to shell/lifter rotation. 2) For a given ball load (Lf), the void fraction available for pulp hold-up (H) for the ascending portion of the load is approximately 0.4 Lf. In the descending portion, it is greater than this and increases with fraction critical speed (Fc) because of load expansion. 3) Increasing the feed rate increases pulp hold-up and progressively fills the available void space. At a critical flow rate, which depends on system geometry, hydraulic head and pulp rheology, void filling reaches its limit; a pool forms rapidly and fills available space outside the ball load and up to the overflow level. Prior to this, pulp discharges mainly along the ascending rim of the overflow. 4) For a small mill (Lo et al., 1990), it has been shown that with increasing feed rates the critical filling is at or near 50% of the mill volume. Power drops rapidly when this level is reached, as required by the torque formula. 5) The transition to overload is associated with the following phenomena: a) The decrease in power draw. b) Damping of mill sound. c) Reduced comminution of coarser feed sizes, probably due to reduced direct impact in the presence of a pool. d) Increased circulating loads, which further intensify the overload, and increased density of cyclone underflows, which can lead to roping. e) Conditions beyond overload are not known because feed rates are not delibelrately increased beyond this point. f) The existence of the phenomenon limits the capacity of a mill with a fixed set of operating conditions and can prevent the balancing of hard ore feed rate decreases by increases in soft ore rates.

Jan 1, 1992

By HOWARD I. OSHRY, James W. Ballard, H. H. Schrenk

Photometric instruments were designed and built for use with X- ray and spectrographic apparatus for the investigation and analysis of a variety of materials of hygienic interest . The instruments are simple in design , may be constructed economically , and have a number of features that make them stable and easy to operate . They are readily adaptable for measurement of either X - ray diffraction patterns or spectrographic films or plates . Because of these features and the interest shown in the instruments , they are described in detail , and reference is made to their application in the laboratory .

Apr 1, 1942

By J. Klemenic

This paper presents an analysis of gold production and prices over an extended period. Production patterns are provided for the world as a whole and for the five major producing countries. Gold prices as a function of interest rates, as measured by municipal bond rates, are given for the period 1947 to the present. World gold production has had a phenomenal increase since 1980, with the exception of South Africa, all major producing nations participated in this increase, even though the price of gold generally has been decreasing since the high level attained in 1980.

Jan 1, 1993

By Lon Santis, Gregory M. Rumbaugh, Christopher Mark

This paper examines the relevant theory, experience, and past practices relating to development mining near gas or oil wells. It addresses setback distance for both coal and stone room-and-pillar mining. This study also involved a review of accident reports involving well interceptions and downhole well surveys. It provides technical considerations for decisions regarding safe setback distances for development mining throughout the United States. The study’s scope is limited to mining near active or inactive (i.e., non-producing, abandoned or inadequately plugged) wells with known surface locations.

Jun 25, 2024

By H. P. Hamlin, W. A. Grosh

Samples of clays , shales , and argillites from 21 locations were subjected to preliminary bench- scale tests for bloating properties , and several samples were tested for ceramic properties . Samples showing favorable bloating properties were further tested in a pilot - plant - scale rotary kiln . Physical characteristics and concrete -making properties of the bloated products were determined . The Decorah shale from one area made a suitable material for a lightweight aggregate ; however , the limestone layers in the formation must be eliminated or the resulting activated lime must be controlled by quenching .

Jan 1, 1963

By Edward (Ted) R. Lord

The application of thickened/paste tailings for surface disposal has been practiced for many years but has recently started to gain wider international acceptance. With tailings ponds coming under increasing environmental scrutiny, there is growing momentum towards mine/tailings plans that greatly reduce the size or even eliminate tailings ponds completely. This paper provides examples from the author&apos;s own experiences of the application of thickened/paste tailings for surface disposal in different countries, under different climatic conditions and in different industries. The paper will also comment on current research initiatives and future trends.

May 1, 2001