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By Cahit Helvaci, Robert B. Kistler

Borates are defined as ' 'salts or esters of boric acid; a compound containing the radical B203" (Bates and Jackson, 1987). Borates are defined by industry as any compound that contains or supplies boric oxide. A large number of minerals contain boric oxide, but the three that are the most important from a worldwide commercial standpoint are: borax, ulexite, and colemanite. These are produced in a limited number of countries (Fig. 1), dominated by the United States and Turkey, which together furnish about 90% of the world's borate supplies (Lyday, 1991). Production in the United States originates in the Mojave Desert of California; borax and kernite are mined by US Borax from its large deposit at Boron. Borate containing brines are pumped from Searles Lake by North American Chemical Co., and a limited amount of colemanite is mined by Newport Mineral Ventures from Death Valley. Turkish production is controlled by Etibank, the national mining enterprise, which supplies most of the commercially traded ulexite and colemanite from mines in the Bigadic and Emet Districts, plus borax from the huge deposit at Kirka. Borate minerals have been employed in a wide range of uses for many centuries, dating from at least the 8th century when they were used primarily as a flux for assaying and refining gold and silver. Their valuable properties and relative rarity soon stimulated international trade in borates; Marco Polo claimed to have trans- ported Chinese borate minerals from Tibet to Europe, and his home port of Venice was the center for borate imports and use throughout the Middle Ages (Travis and Cocks, 1984). Borates were traded at relatively high prices for highly specialized applications into the late years of the 19th century. At that time they were being used for medicines, food preservatives, ceramic glazes, and in expanded applications as metal fluxes. It was in that era that borax was discovered in Clear Lake, CA, and more significantly, the playa deposits of western Nevada were found and exploited by F.M. "Borax" Smith and others. Research and development by Smith's company began the evolution of borates from a high priced commodity with a few specialized uses to the relatively low priced chemical raw material used in large tonnages on a worldwide scale today. Borates are often defined and sold by their boric oxide or B,03 content, and most statistical data are listed in tons of B203. Of the products sold by the industry, borax pentahydrate or 5 mol and boric acid are the most commonly traded commodities. Boric acid plants are operated by all of the major borate producers. Glass fiber insulation is the major end use in the United States followed by textile glass fiber and borosilicate glass, detergents, and ceramics. Detergent usage continues to be a major end use in Europe.

Jan 1, 1994

By Cyril Stanley Smith, Earl W. Palmer

STRIP of any of the metals used for deep drawing operations occasionally yields cups that are defective because of a rim that varies in height around the cup in a wave-like manner. Some such defects are traceable to tools or other press factors, but when the protuberances formed (usually four in number on brass and other copper alloys) are symmetrically disposed with respect to the rolling direction of the strip, they are invariably attributable to the metal. The effect is known as "earing" and the protuberances are called "ears." Other terms frequently heard are "tips," "scallops," and "corners." It is recognized that the effect is most commonly a result of a directional crystal structure produced by rolling and annealing operations in the manufacture of the metal strip. 'Numerous papers dealing with various aspects of the earing effect have appeared in the literature, those listed in the references1 being especially interesting and valuable. An investigation of the factors influencing earing of brass cups has been in progress in the laboratories of the American Brass Co. for several years, and it was thought desirable to make some of the results generally available in summarized form. The present paper discusses many factors that do and do not contribute to ear formation. In addition, a section is devoted to methods of minimizing the earing tendency of brass sheet by proper selection of the cold-rolling and annealing schedule by which it is produced. In the space available, it is impossible to quote detailed experimental procedures and numerical results. However, the authors make no statement that they do not believe to be properly substantiated, either by experimental evidence obtained under laboratory conditions or by experience in the actual production of deep-drawing brass in the brass mill. MECHANISM OF EAR FORMATION It must be clearly understood that the formation on cups of symmetrical ears, four or more in number, is attributable solely to the strip metal, and results from the strip having different deformation characteristics in different directions. The tools used in the drawing process, or the type and completeness of lubrication of the strip, have nothing to do with the problem of ears, although they do, of course, greatly affect the "drawing quality" of the strip and the general appearance of the cup. A single tip may be drawn up on the rim of a cup because of misalignment of the tools, or because the gauge of metal varies from side to side of the strip. The two-ear form that sometimes appears is also traceable to gauge variations. However, the four-ear and six-ear symmetrical forms that we are concerned with here are caused by factors inherent in the structure of the metal itself.

Jan 1, 1942

By M. K. Yen, W. R. Hibbard

Previous studies of plastic deformation of metals have emphasized the important role of bending and constraints during strain under relatively pure stresses.1"5 Some new phenomena such as early conjugate slip6 and polygonization7 are intimately concerned with the relief of bending stresses, the former by slip and the latter by a process analogous to re-crystallization. However, few analyses of the bending deformation of single crystals were found in the literature, and those8,9 are sufficiently previous to the modern interpretations of slip to invite further investigation in this area. The transverse bending mode of testing, using the two-point loading method, was selected because the center portion of the specimen may be considered as under a theoretically pure bending stress with a uniform bending moment. Considerable attention was given to both the lattice distortion and flow characteristics of the crystals during deformation. Experimental Proeedare A specimen under the action of equal and opposite couples at both ends is said to undergo pure bending. The shear and moment diagrams of a specimen under the two-point loading method of transverse bending are shown in Fig 1. The moment over the middle-third of the span is equal to PL/6, and the vertical shear is zero. Fig 2 (A) illustrates the stress distribution in the elastic range on a plane across the middle of the specimen. It can be seen that the normal stress has a maximum value at the extreme surfaces on the tension and compression sides, and decreases proportionately to zero as it approaches the neutral plane. However, when the plastic range is reached, the stress distribution is no longer a straight line relation, but changes in a manner which can be best illustrated as shown in Fig 2(B). The following calculation and stress analysis are mainly in accordance with the works reported by Timoshenkol0 and Kochendörfer.9 From the simple beam formula, the maximum normal stress will occur at the surface of the specimen. For a round specimen with a radius r and for a rectangular specimen with a height 2h and width 2b, the maximum normal stress, Sp, will be given by the following formulas: For round specimen: 2PL Sp = 3pr3 [1] For rectangular specimen: Sn = 8bh2 [2] Since it is reasonable to consider that slip takes place under the same conditions as in uniaxial loading, the resolved shear stress S?, along the operative slip direction will be as follows: For round specimen: 2PL sin x cos ? Sp = 3pr3 sin x cos ? [3] For rectangular specimen: PL S8 = 8bh2 sin x cos ? [4] where X is the angle between the specimen axis and the slip direction and X, the angle between the specimen axis and the major axis of the glide ellipse. It was also reported by Kochenclorfer9 that the critical bending moment, that is, the bending moment exerted on the specimen to initiate slip, should be higher than the value given by the equations stated above. Based

Jan 1, 1950

By J. L. Foster, G. R. Gray, T. S. Chapman

The wall-building properties of salt-water drilling muds can be improved markedly by the addition of: (I) natural gums, such as traga-canth, karaya, and ghatti; (2) seaweeds, such as Irish moss; or (3) gelatinized starch. Results of laboratory tests have been confirmed by field trials. For drilling operations in which the mud becomes contaminated by salt, either through penetrating salt-bearing rocks or by addition of sea water to the mud, the added cost resulting from the use of one of the substances listed above is more than offset by freedom from stuck drill pipe and ease in running casing. Introduction It has been recognized for many years that oil production might be seriously hampered by infiltration of water from the drilling mud.l-4 As knowledge of the mechanism of the wall-building process advanced, methods were developed for evaluating the filtration characteristics of muds.5-ll The wall-building properties of freshwater muds are commonly regulated by the addition of bentonitic clays, or of agents to promote the dispersion of the natural mud solids. When strata bearing soluble salts are encountered in the course of drilling, the salts are incorporated in the mud; the clay solids are flocculated and water loss is increased tremendously. Methods gen-crally used in controlling filtration of freshwater muds are no longer applicable. The problem of reducing water loss from salt-water muds is not confined to any particular area, but is acute in parts of West Texas. Salt beds several hundred feet thick must be penetrated before the oil-bearing formation is reached. Since the formation drilled does not provide mud-making material, it is necessary to use large quantities of commercial clays, and even the best commercial clay does not afford relief from the problem of high filtration. A laboratory study has been made of methods of improving the filtration characteristics of salt-water muds, and some of the methods have been used in field practice. Laboratory Investigations Procedure Inasmuch as the immediate object of the investigation was the development of means of improving the wall-building properties of muds used in West Texas, an attempt was made to employ muds in the laboratory study comparable to those in field use. Samples of muds used in drilling the producing formations in six wells were secured. The properties of these samples are summarized in Table I, which lists the densities, viscosities, filtrations, and analyses of the filtrates for calcium, chloride, and sulphate. Viscosity was measured in the Stormer viscosimeter at 600 r.p.m. Water loss was determined at 80°F. with the Baroid low-pressure wall-building tester8 at a pressure of 100 lb. per sq. in. Filtration rates are considerably higher than those of usual fresh-water muds, which amount to about 20 C.C. in 30 min. Water loss was so rapid in samples 4, 5 and 6 that filtration was complete in less than 10 min. and the values for 30 min. were extrapolated from the rates at shorter

Jan 1, 1942

By Henry Faul

Measurement of radioactivity of rocks and ores has developed into a complete method of geophysical exploration. The problem falls into three natural categories: (1) surface radiation measurement in the field and underground; (2) radioactivity logging of drillholes; and (3) laboratory analysis of samples. Portable counters are used in the field for tracing radioactive formations and for quanti tative estimates of radioactive content of surface rock. Wartime advances in battery design make it possible to construct small precision counters that can be carried easily. Even the smallest conventional diamond drillholes can be logged, and actual content of the radioactive element can be measured. The exact grade of very thin active layers or veins can be estimated only approximately. Samples may be analyzed for their alpha, beta or gamma activity, and beta assaying is the best suited to rapid routine operation. Simple calibration with standard samples is sufficient for rough work, but a density correction is necessary when greater precision is required. Samples with high emanating power should be fixed and stored for three weeks to reestablish the radium-radon equilibrium prior to precision assaying. Carno-tite can be fixed by sintering or molding with plastics. Among the important new developments, a low-voltage Geiger tube has been 'designed recently, and crystal scintillation counters hold great promise for high-efficiency gamma-ray measurement. Introduction During the last few years we have witnessed an unprecedented rise in the demand for radioactive minerals, coming as a direct consequence of the discovery of nuclear fission and subsequent developments, the full impact of which is by no means in sight even now. It remains certain, however, that radioactive minerals, and especially those which can be used as ores of uranium and thorium, will continue to be of great interest not only to the prospector and mine operator but also to the various inspection parties envisioned by most of the schemes advanced for the control of nuclear energy on a world-wide basis. It is clear, therefore, that the measurement of radioactivity in rocks in the field as well as in samples in the laboratory has become a method of geophysical exploration of some importance. If we consider the recent technological advances in the general fields of nuclear physics and electronics it seems proper to review the present status of the methods and procedures of radiological exploration. General Considerations Equilibrium If we take a fixed amount of uranium that has just been purified, some of it will immediately start decaying into its first daughter element which in turn decays into its own daughter and so on down the line until the last daughter is reached—a stable isotope of lead. The rate at which a radioactive element decays is frequently expressed as the half-life, which is the length of time required for the decay of half the atoms in a given amount. The half-life is inversely proportional to the decay constanl X which is defined as the number of atoms which decay in one unit of time divided by

Jan 1, 1949

By Lawrence B. Wright

The Republic district, Washington, is of new interest because of the discovery of new gold-silver ore within a unique structural pattern. The camp was revived in 1937 fol1owing installation of a plant to treat low-grade disseminated ore at Knob Hill and further stimulation followed discovery of "cross vein" breccia ores in 1939. Previous writers 1-2 ascribed the quartz veins to a latite porphyry stock, but are in disagreement as to its precise location and extent. This study leads to the conclusion that the ores have a more profound parentage linked to a broad system of thrust faults and folds, the mechanical origin of which is related to a southward trending (Sanpoil) syncline connecting with the Lewis and Clark zone of shift described by Billingsley and Locke3 in 1939. The Republic anticliue and a cross anticline recumbent against Cretaceous granodiorite. and involving some 4000 ft of Eocene andesite flows and early Miocene lake beds, localize the ores, mainly along the east flank, in a series of openings simulating drag folds and steeper than the folded flows. These broad structural features no doubt reach deeply into the basement rocks, where at appropriate crossings and junctions it is suggested that heat effects gave rise to ore-making materials, including, in this instance, intrusive breccias that later were mineralized, and comprising the broader bodies of new ores. The breccia ore is seen crosscutting the earlier narrow quartz veins with a welding of the two at junction areas by a second surge of ore minerals. The ore mined and developed since 1937 equals district production from 1896 to 1937 The ores are typified by cherty quartz, adularia and some barite, with fine pyrite and marcasite, polybasite, pyrargyrite, tetrahedrite and gold. Selenium is present, possibly with gold, as a normal selenide. The disseminated ores, as well as the vein and breccia ores, are localized principally in one 500-ft flow (Knob Hill andesite), which has been traced around the crest of the low northward-plunging Republic anticline. The gold-silver ratio in the earlier narrow veins is about I to 4 and in the disseminated and breccia ores, I to 7. The latter higher silver ratio is deemed to reflect the character of the second surge of mineralization. Sills and dikes of the Columbia River (Miocene) basalt cut the folded structure and ore, thus placing the mineralization in the middle Miocene. Introduction The Republic district of north central Washington is of new interest because of the discovery, development and extraction of new gold-silver ore; also, because of a unique local structural pattern believed to be integral with the broader tectonic mechanism of the continental framework. This district had 40 years of modest rating following its discovery in 1896. Its narrow ore bodies, complex mineralogy. and early inadequate metallurgy, together with the apparent bottoming of ore near 1000 ft, limited production to 300,000 oz of gold and 1,000,000 oz silver between 1897 and 1914. The camp was then reduced to lease Life until 1937, when the gold price increase of 1933 to $35 per ounce

Jan 1, 1949

By Henry Faul

Measurement of radioactivity of rocks and ores has developed into a complete method of geophysical exploration. The problem falls into three natural categories: (1) surface radiation measurement in the field and underground; (2) radioactivity logging of drillholes; and (3) laboratory analysis of samples. Portable counters are used in the field for tracing radioactive formations and for quanti tative estimates of radioactive content of surface rock. Wartime advances in battery design make it possible to construct small precision counters that can be carried easily. Even the smallest conventional diamond drillholes can be logged, and actual content of the radioactive element can be measured. The exact grade of very thin active layers or veins can be estimated only approximately. Samples may be analyzed for their alpha, beta or gamma activity, and beta assaying is the best suited to rapid routine operation. Simple calibration with standard samples is sufficient for rough work, but a density correction is necessary when greater precision is required. Samples with high emanating power should be fixed and stored for three weeks to reestablish the radium-radon equilibrium prior to precision assaying. Carno-tite can be fixed by sintering or molding with plastics. Among the important new developments, a low-voltage Geiger tube has been 'designed recently, and crystal scintillation counters hold great promise for high-efficiency gamma-ray measurement. Introduction During the last few years we have witnessed an unprecedented rise in the demand for radioactive minerals, coming as a direct consequence of the discovery of nuclear fission and subsequent developments, the full impact of which is by no means in sight even now. It remains certain, however, that radioactive minerals, and especially those which can be used as ores of uranium and thorium, will continue to be of great interest not only to the prospector and mine operator but also to the various inspection parties envisioned by most of the schemes advanced for the control of nuclear energy on a world-wide basis. It is clear, therefore, that the measurement of radioactivity in rocks in the field as well as in samples in the laboratory has become a method of geophysical exploration of some importance. If we consider the recent technological advances in the general fields of nuclear physics and electronics it seems proper to review the present status of the methods and procedures of radiological exploration. General Considerations Equilibrium If we take a fixed amount of uranium that has just been purified, some of it will immediately start decaying into its first daughter element which in turn decays into its own daughter and so on down the line until the last daughter is reached—a stable isotope of lead. The rate at which a radioactive element decays is frequently expressed as the half-life, which is the length of time required for the decay of half the atoms in a given amount. The half-life is inversely proportional to the decay constanl X which is defined as the number of atoms which decay in one unit of time divided by

Jan 1, 1949

By Mark D. Tabak

Measurments of the transient photoconductivity in fillns of amorphous selenium with blocking- contacts haue been used in studying the transport properties. The results shozu that the transport of free carviers cannot be explained in terms of a model using bulk trapping. Measurments of the photocurrent-applied field characteristic as a unction of sample thickness do not pvoduce the scaling lau,s approps-iate lo a range-limited model. THE investigation described here was undertaken to explore the mechanisms of transport in amorphous selenium films. These films are used in xerography, where a photoconductor is charged electrostatically and then exposed to light to form a latent image. The sensitivity that one can expect when operating in this mode is directly related to the transport properties of the photoconductor material. The study of photoconductivity at high fields in insulating materials is often complicated by contact effects. Injection from the contacts can easily mask the fundamental transport processes that are being studied. A technique is described in this paper that allows a study of photoconductivity and transport processes in amorphous selenium films without the complicating effects introduced by contacts. Accordingly, the samples are prepared using insulating films between the sample and the metal electrodes, where the electrodes are capacitively coupled to the surfaces of the sample under study. A transient measurement is performed with pulsed light, and the photocurrent measured near the beginning of the pulse before the field is distorted by polarization at the blocking elec- trodes. A similar method has been described by Manyl using pulsed electric fields in studying the high field transport in insulating cadmium sulfide. EXPERIMENTAL It is possible to eliminate undesirable contact effects and maintain uniform high fields across the sample by using blocking electrodes and measuring the current-field characteristic under transient conditions. The sample configuration is shown schematically in Fig. 1. Each of the gold electrodes is separated from the amorphous selenium film by a layer of insulating plastic (Formvar) approximately 2000~ thick. The electrode on the front surface is semi-transparent to allow illumination of the sample. The whole configuration is mounted on a KEL-F substrate, which is a transparent insulating plastic having a thermal expansion coefficient that allows low-temperature measurements without cracking the selenium film. Fig. 2 shows a block diagram of the measurement apparatus. Light was obtained from a 450-w Xenon arc lamp, the intensity of which was controlled by stainless-steel screen filters and monitored by a pho-tomultiplier which was calibrated periodically against a thermopile. A camera shutter operated at 1/200 sec provided the light pulse and a synchronized signal to the oscilloscope. The photocurrent transient is ob-served with a high-speed picoammeter (response time of 1 msec) the output of which is displayed on an oscilloscope. The applied voltage is constant throughout the transient measurement. The selenium films were prepared by evaporation of four 9's pure selenium shot supplied by Canadian Copper Refiners. Spectrographic analysis showed about 1 ppm of Te and Fe, 5 ppm of C1, and 0.05 ppm

Jan 1, 1968

By T. K. Prentice

The January-February number of the Journal of the Chemical Metallurgical and Mining Society of South Africa, 1943, is made up entirely of a discussion of Ball Wear in Cylindrical Mills. Following the principal paper by T. K. Prentice are several remarkably pertinent and carefully prepared discussions. Few persons in this country would be likely to see this publication, and since the information presented is new and of current interest, it seems desirable to abstract and review this publication for the benefit of the members of the A.I.M.E. The purpose of the investigation is stated in the first two paragraphs of Prentice's paper, as follows: Early in 1941, The Chamber of Mines Steel Products, Limited, initiated a series of tests under semi-working scale conditions to determine, if possible, those physical and chemical properties of a ball which make it resistant to wear when used in a cylindrical mill as a grinding medium, with the primary object of incorporating those beneficial qualities in the balls being produced at their works. This paper describes the tests carried out and discusses the results obtained. From these results it was possible to formulate a new theory relating to ball wear in cylindrical mills. This theory is presented in the second portion of this paper. Practical Ball-mill Tests in a Cylindrical Mill Part I of the paper begins with a discussion of the methods used for the manu- facture of grinding balls in South Africa. The following paragraph is of particular interest. The cast steel ingots, 4¼ in. square by 3 ft. 6 in. long, are re-heated in a gas-fired sloping stationary-hearth furnace and then rolled in a six-pass continuous mill into 25/8 in. round billets. Some of these billets are then removed and cut into suitable lengths for forging into 4 in., 3¼ in. , 3 in. or 2½ in. balls by means of three Drop and two Beche hammers, but the greater number, whilst still at about 1,000, pass directly into a set of scroll rolls which produce, in an ingenious manner, finished 3 in. balls direct from the 25/8 in. billets. Except in special cases, all balls are allowed to cool in the atmosphere and are not water quenched. Details of the Tests In order to enable the reader to evaluate properly the results and conclusions in the rest of the paper and in the discussions following the paper, most of the information presented by the author under this heading is quoted: The testing unit was a nominal 30 in. diameter and 18 in. long centre discharge Denver Ball Mill. The ore pulp to the ball mill comprised a small portion of the normal feed to one of the fourteen City Deep 5 ft. 6 in. X 22 ft. tube mills, and the grinding media consisted of the balls under test plus other balls to give the desired load. The running time of the test-mill was divided into approximately equal periods of five days 13½ hours each. The usual procedure was to examine and make up the load

Jan 1, 1947

By H. E. Bartlett

This paper deals with the sampling and mass measurement for ore delivered from a shaft to a processing plant and the contribution of the data from these measurements to the metal balances from shaft deliveries to final metal production. Accurate measurement of the grade and tonnage of run-of-mine ore is important for four main reasons; ? It enables the measurement of the production from different profit centres to within statistically determined confidence limits for daily, monthly, or annual averages. The profit centres could be individual shafts within a mining complex or ore treated on a toll basis ? The monthly production at shaft head is compared to the grades and tonnage determined from underground sampling and mass measurement in terms of a shaft call factor ? The sum of the production from the shafts is the input to concentrators. This input is a major part of the total input into a complex with concentrators, smelters, and refineries. In terms of the Codes of Practice for Metal Accounting the inputs are compared to outputs and inventory changes to assess the efficiencies and unaccounted losses or gains at the various stages in the flow of metal from source to market ? On a daily or daily moving average basis, the grades and tons from shafts are monitored and compared against these quantities from underground measurements. This acts as a control on off-reef mining, dilution, and other factors underground. Accurate measurement of grade of ore at the shaft head has been a challenge because of the large particle size. The conventional wisdom has been that ore can be sampled accurately only after it has been milled to give a slurry that is sampled as feed to a flotation process. However, when the ore fed to a flotation plant comes from multiple sources each source has to be sampled separately. So, relying on the grades determined using the sampling of concentrator input with cross-stream slurry samplers is not an option for determining the grade from an individual shaft. Impala has developed a system for sampling and weighing run-of-mine ore from multiple shafts. The system involves sampling the inputs to the plants using cross-belt (hammer) samplers and weighing the deliveries using in-motion railway weighing systems. Many samples are taken. Individually they have a high variance but, as a consequence of the averaging effect of large numbers and as shown by statistical analysis, the mean results are fit for the purposes of daily grade control for shafts and for monthly accounting of production from individual shafts. In the metal accounting systems at Impala, the measurement of input, including ore and toll-treated material is compared to the output in the form of final metal and tailings losses, as well as any inventory change that takes place, in order to determine a final metal balance from mill feed to product. The calculated inventory is compared to that measured, and the difference, or unaccounted- for metal, is then reported as a percentage of input. The balances obtained over several years yields balances for platinum that are below 1% imbalanced. Keywords metal balancing, platinum mines, AMIRA codes of practice, metal accounting, sampling, run-of-mine ore, statistical analysis.

Jan 1, 2014

By D. Havlena, A. S. Odeh

The use of the straight-line method of solving the material balance equation is illustrated by means of six field cases. Also, the application of statistical criteria to arrive at the most probable answer is shown. The theory underlying the straight-line method of solution and the applicability of the statistical criteria was presented in a previous paper.' The field cases include saturated and undersaturated oil reservoirs with and without water drive. The aquifers discussed are: limited radial, infinite radial, very small aquifer and infinite linear. The field cases also include a gas reservoir producing under water drive. INTRODUCTION In a previous paper,' the authors presented the theory underlying the solution of the material balance as an equation of a straight line. The appropriate equations for various material balance cases as well as the methods of analysis and interpretation with comments and discussion were also included. To illustrate the various theoretical cases treated previously, five field cases are analyzed in this paper by employing the straight-line method of solving the material balance equation (MBE) and one example previously published is referred to. The use of statistical criteria to arrive at the most probable answer is also shown. All the field examples presented, except Case 2, are excerpts from complete reservoir studies. To illustrate the method, only sections specifically dealing with the material balance principles are included. Additional geologic information and basic data are reported to better acquire an understanding of the cases and thus to better follow the reasoning that suggested the successful application of the straight-line method of solving the MBE. The six cases are: (1) saturated reservoir, small gas cap, limited aquifer; (2) saturated reservoir, very small gas cap, infinite aquifer; (3) undersaturated-saturated reservoir, very small aquifer; (4) highly undersaturated reservoir, no water drive; (5) high undersaturated one-well reservoir, limited aquifer; and (6) gas reservoir, infinite linear aquifer. THE D4 SAND, GUICO FIELD, VENEZUELA The D, sand, which was discovered in 1943, is presently in a depleted state. Since its discovery it has produced under water drive, gas-cap-gas expansion, and solution gas drive. In Nov., 1947, water injection was initiated to arrest further pressure decline. When discovered, the D, sand was a saturated reservoir with a gas cap /oil zone volume ratio m estimated volu-metrically at 0.0731, an average permeability of 500 md, a porosity value of 25 per cent, and an oil viscosity at reservoir conditions of 0.3 cp. The volumetrically determined stock-tank oil initially in place was 23.1 million bbl. The volumetrically weighted physical data and production data available until Nov., 1953 are reported in Table 1. In Ref. 1, the effects on the straight-line plot of various values of ro/r for a constant ?to, or of various dimen-sionless times for a constant r8/r10 were theorized and were illustrated in Fig. 3A of that reference. In this field case, the previously theoretically predicted effects are established. Thus, the MBE calculations using Eq. 3c of Ref. 1 were performed for various r6/r10 and dimension-less time values. Eq. 3c of Ref. 1 is:

Jan 1, 1965

By Albert J. McIntosh

With petroleum consumption declining temporarily after V-J day, the oil industry is urged to use this period as a kind of stopgap to rebuild its war-depleted inventories and help cushion the effect of this decline on producers and refiners. Higher inventories should be reestablished, since recent experiences have indicated that, by and large, the present inventories of crude oil are too low even with the tremendous current production available. The following analysis indicates that inventory levels could be built up to about 490,000,000 bbl. by the end of 1947, an increase of about 40,000,000 bbl. over the reported stock estimated for the war's end. If at the end of the war the military have some 20,000,000 bbl. on hand, this inventory will either be resold to the industry or certain demands that have been assumed to be met by industry will be supplied out of these military stocks, which would leave about 20,000,000 bbl. (net) to be built up from current production. For stock rebuilding the industry could use 10,000,000 bbl. of crude plus 10,00,000 bbl. of products, totaling 20,000,000 bbl. If this were spread over a year, this would mean 55,000 bbl. a day. By analyzing the average inventories held in a year with the total quantity of goods handled during the year, the following study and tables indicate how far the inventories should increase in the immediate postwar period. Introduction For the period immediately following V-J day, most of the petroleum economists have forecast a considerable decline in the total consumption of petroleum and its products in the United States. This will be caused by the elimination of most of the military demands and the inability of civilians to immediately replace automobiles, burners, etc., and thus increase their requirements to make up for the military decline. When the automobile industry has been back on full production for two or three years, civilians will be able to consume much larger quantities of gasoline. Delay in the manufacture of new oil burners and the time it takes to construct new homes, adds up to the same story for distillate fuels. In reviewing this outlook, the question has arisen whether the petroleum industry should not use this period of lower consumption as a kind of stopgap to rebuild its war-depleted inveritories and help cushion the effect on producers and refiners of this sudden drop in requirements. Some persons have indicated that hundreds of thousands of barrels a day could be used for this purpose extending over a year or more. Refineries will be in existence, which could run over 5,000,000 bbl. of crude oil a day and crude-oil production might be running 600,000 to 700,000 bbl. a day above the demands now forecast for the period after V-J day. Reasons for. Making Inventories In order to plan intelligently for this period, the petroleum industry should determine the needs for the establishment of higher inventories for crude and petroleum products than have been carried during the war. The reasons for trying to make such a determination are as follows:

Jan 1, 1945

By G. R. Gray, T. S. Chapman, J. L. Foster

The wall-building properties of salt-water drilling muds can be improved markedly by the addition of: (I) natural gums, such as traga-canth, karaya, and ghatti; (2) seaweeds, such as Irish moss; or (3) gelatinized starch. Results of laboratory tests have been confirmed by field trials. For drilling operations in which the mud becomes contaminated by salt, either through penetrating salt-bearing rocks or by addition of sea water to the mud, the added cost resulting from the use of one of the substances listed above is more than offset by freedom from stuck drill pipe and ease in running casing. Introduction It has been recognized for many years that oil production might be seriously hampered by infiltration of water from the drilling mud.l-4 As knowledge of the mechanism of the wall-building process advanced, methods were developed for evaluating the filtration characteristics of muds.5-ll The wall-building properties of freshwater muds are commonly regulated by the addition of bentonitic clays, or of agents to promote the dispersion of the natural mud solids. When strata bearing soluble salts are encountered in the course of drilling, the salts are incorporated in the mud; the clay solids are flocculated and water loss is increased tremendously. Methods gen-crally used in controlling filtration of freshwater muds are no longer applicable. The problem of reducing water loss from salt-water muds is not confined to any particular area, but is acute in parts of West Texas. Salt beds several hundred feet thick must be penetrated before the oil-bearing formation is reached. Since the formation drilled does not provide mud-making material, it is necessary to use large quantities of commercial clays, and even the best commercial clay does not afford relief from the problem of high filtration. A laboratory study has been made of methods of improving the filtration characteristics of salt-water muds, and some of the methods have been used in field practice. Laboratory Investigations Procedure Inasmuch as the immediate object of the investigation was the development of means of improving the wall-building properties of muds used in West Texas, an attempt was made to employ muds in the laboratory study comparable to those in field use. Samples of muds used in drilling the producing formations in six wells were secured. The properties of these samples are summarized in Table I, which lists the densities, viscosities, filtrations, and analyses of the filtrates for calcium, chloride, and sulphate. Viscosity was measured in the Stormer viscosimeter at 600 r.p.m. Water loss was determined at 80°F. with the Baroid low-pressure wall-building tester8 at a pressure of 100 lb. per sq. in. Filtration rates are considerably higher than those of usual fresh-water muds, which amount to about 20 C.C. in 30 min. Water loss was so rapid in samples 4, 5 and 6 that filtration was complete in less than 10 min. and the values for 30 min. were extrapolated from the rates at shorter

Jan 1, 1942

By David Cooper, Susan Robertson, William Wiehagen, Launa Mallett, Charles Vaught, Joan Dickerson, Richard Conkle, ROBERT PETERS, Mike Brnich, Charles Urban

This trainer’s guide is designed as a reference manual. The purpose is to offer information and examples to skills trainers to assist them in structuring training for new operators of Walk-Thru roof bolting machines. Trainers can use this manual as a resource for helping trainees learn, understand, and apply knowledge and skills. In this sense, the guide is not prescriptive. It is designed to offer information and trigger ideas on what might be done to accelerate learning to those who are new to the roof-bolting task. On-site trainers can modify this guide to fit their conditions, machines and equipment, and work procedures. They can integrate roof control plans, company policies and procedures, and operators’ manuals from the manufacturers of the original equipment into this guide. Every trainee is different and will come to the job with varying levels of relevant knowledge and skills. The trainer’s decisions on where to start, how to organize the on-the-job and classroom training portions, and when and how to offer different aspects of the training will be based on (1) a pretraining assessment of the trainee’s knowledge and skills and (2) the trainer’s experience in conducting skills training. The “Skill Check” section might be useful for deciding where training should start among miners who have underground experience but limited knowledge of roof-bolting techniques. Every job carries a learning curve and likely has a number of “teachable moments” where significantly new knowledge and skills can be learned. The videos on the DVD that accompany this guide can be shown at the beginning of training to give trainees an idea of what the job entails and related requirements. They can also be used within the training cycle (after the trainee has some experience in the job) to reinforce key points or as a trigger for eliciting questions about particularly difficult parts of the job. The video segments are meant to be visual models of good performance. They are designed to elicit discussion on good (lower risk) ways to do the job. In this context, they can be used very creatively at different times within the training cycle. The section on “Talking Points” offers a number of questions that can be used in the classroom to support and elaborate on certain aspects of the job duties. If the trainee has a fair amount of underground experience, some of the questions can also be used to support the pretraining assessment (i.e., skill check) of knowledge and skills. Likewise, some of the questions can also be used while teaching on the job to reinforce key points affecting safety, production, or maintenance. The section dealing with a mine’s roof control plan should be used at various times in the training cycle to make sure the trainee understands the plan and knows how to apply it in performing the job. The supplemental materials offer additional resources that can be used to support initial job training or follow-up. Learning continues well after an individual has been trained. The supplemental materials can help reinforce good operating skills and provide an opportunity for further discussion on better ways to do the job.

Jan 8, 2006

By E. Rosseland

Glencore Nikkelverk is operating its Chlorine Leach Process in Kristiansand, Norway, producing nickel, copper and cobalt metals by electrowinning. The copper tankhouse, with an annual capacity of 40 000 tons, is based on traditional technology with copper starting sheets and cast lead anodes. Due to the integration of this copper sulphate process in a nickel chloride refinery, operating conditions are unique. In recent years, operating costs have escalated, and health, safety and environment are top priorities. Test work on a new copper process involving permanent cathodes was therefore initiated in 2007, and a pilot plant was started up in 2012. The objective was to introduce innovative technologies and tailor these to be robust in the Nikkelverk process, to form a basis for a new sustainable copper tankhouse with a high degree of automation. Key learnings from more than 10 years of R&D work is presented, focusing on cathode materials and copper metal deposition including product quality, robotic stripping, coated titanium anodes, electrode contacts and alignment, electrode current monitoring with Hatch HELM tracker technology and acid mist capture using cell hoods with off-gas scrubbing. The new copper tankhouse project was approved in December 2018, and commissioning is planned in 2022. INTRODUCTION The Kristiansand nickel refinery was started up in 1910, processing nickel-copper matte originating from Norwegian mines. It was the first industrial plant in the world to produce nickel by electrolysis using the Hybinette electrorefining process. After roasting to burn off sulphur in the matte, copper was leached and recovered as cathodes by electrowinning with lead anodes. In the first years, the copper cathodes were fire- refined and cast into ingots for sale (Thonstad Sandvik, 2004). The Nikkelverk refinery was acquired by Falconbridge Ltd. in 1929, and since then matte from Sudbury, Canada has been the main feed source. The Hybinette process was in operation until 1975 when conversion to the newly developed Chlorine Leach Process was started (Stensholt, Zachariasen, & Lund, 1986). In this process still used today, nickel and part of the copper in the matte is leached using chlorine gas generated on dimensionally stable anodes in the nickel and cobalt electrowinning tankhouses, as illustrated in Figure 1. The presence of dissolved copper ions in the strong chloride leach solution is essential for effective chlorine absorption and nickel dissolution. To improve copper-nickel separation, slurry from the atmospheric leach is pumped to autoclaves and then to cementation tanks for precipitation of copper as copper sulphide, which is collected in filter presses. The leach residue, also containing the precious metals, goes through a 3-stage wash to remove chlorides before being introduced as a slurry to fluid-bed roasters for sulphur removal. The resulting calcine is then leached in spent electrolyte from the copper electrowinning tankhouse, to dissolve most of the copper and also some nickel, cobalt and other elements. After separation of the leach residue, elements like Bi, Te, As and Ag are removed from the strong copper sulphate solution by reaction with metallic copper in three columns in series filled with cut copper cathodes. The purified solution then passes polishing filters before being mixed with spent electrolyte and returned to the electrowinning cells.

Jan 1, 2019

By Rodney G. Ravenscroft

Leasing is not a new phenomenon. Experts have identified its origins as early as biblical times. It is a method of finance that has grown rapidly and is now used in most countries, including those of South East Asia, South America, the Middle East and even the People's Republic of China. Internationally, the leasing world divides fairly easily into two groups and this is determined, by and large, according to whether a country has Anglo-Saxon origins or not. Most of the Anglo-Saxon countries have seen tax-oriented leasing become a sophisticated means of financing the acquisition of large and costly items of equipment and large projects. Countries such as France, Spain and Japan have a highly developed leasing industry but it is not tax-oriented. This paper will not address leasing of this kind. LEASING - THE CONCEPT Wide acceptance of leasing as an alternative for financing capital equipment has grown with the recognition by the users of equipment that it is use and not ownership that generates profits. Whilst this seems obvious, memories of repossession of assets during the Depression and attitudes towards leasing as "last resort financing" have raised strong philosophical resistance that has only recently begun to be overturned. A financial lease is a commitment by way of contract between a user of equipment (lessee) and a financial owner (lessor) under which the lessee makes a series of payments in return for use of the equipment. The lessee is acquiring economic value associated with ownership but not ownership of the equipment itself - that remains with the lessor. A lease is a method of financing the use of an asset; other methods finance the assets themselves. It is the taxation aspects that then become important. The lessee is giving up some or all of the taxation benefits of ownership such as depreciation and investment tax credits. The lessor claims these benefits, as he is entitled to do as owner, and takes them into consideration when determining the level of lease payments that are necessary to generate his required rate of return. These lease payments are, of course, lower than they would have been without those taxation benefits. The lease payments themselves are fully tax deductible. This is tax shelter leasing. The lessor is acquiring taxation deductions that are applied fully and immediately against his other taxable income so as to reduce the amount of tax he is to pay to the revenue authorities. It is this concept that makes financial leasing work. Governments provide incentives by way of tax concessions to encourage capital investment. Governments presume that prudent capital investment will offer employment opportunities, generate sales and streamline economic activity. These, in turn, will lead to the collection of government revenue. It makes no difference at all whether these incentives are claimed by a commercial or industrial owner/user or by a financial owner who makes equipment available for use by industry. Rather, the issue is to ensure that if an incentive is available, it is used so as to achieve its desired results. No greater or lesser incentive is available for leasing and leasing does not misuse the taxation aspects of equipment ownership. The critical issue is whether the full value

Jan 1, 1985

By T. K. Prentice

The January-February number of the Journal of the Chemical Metallurgical and Mining Society of South Africa, 1943, is made up entirely of a discussion of Ball Wear in Cylindrical Mills. Following the principal paper by T. K. Prentice are several remarkably pertinent and carefully prepared discussions. Few persons in this country would be likely to see this publication, and since the information presented is new and of current interest, it seems desirable to abstract and review this publication for the benefit of the members of the A.I.M.E. The purpose of the investigation is stated in the first two paragraphs of Prentice's paper, as follows: Early in 1941, The Chamber of Mines Steel Products, Limited, initiated a series of tests under semi-working scale conditions to determine, if possible, those physical and chemical properties of a ball which make it resistant to wear when used in a cylindrical mill as a grinding medium, with the primary object of incorporating those beneficial qualities in the balls being produced at their works. This paper describes the tests carried out and discusses the results obtained. From these results it was possible to formulate a new theory relating to ball wear in cylindrical mills. This theory is presented in the second portion of this paper. Practical Ball-mill Tests in a Cylindrical Mill Part I of the paper begins with a discussion of the methods used for the manu- facture of grinding balls in South Africa. The following paragraph is of particular interest. The cast steel ingots, 4¼ in. square by 3 ft. 6 in. long, are re-heated in a gas-fired sloping stationary-hearth furnace and then rolled in a six-pass continuous mill into 25/8 in. round billets. Some of these billets are then removed and cut into suitable lengths for forging into 4 in., 3¼ in. , 3 in. or 2½ in. balls by means of three Drop and two Beche hammers, but the greater number, whilst still at about 1,000, pass directly into a set of scroll rolls which produce, in an ingenious manner, finished 3 in. balls direct from the 25/8 in. billets. Except in special cases, all balls are allowed to cool in the atmosphere and are not water quenched. Details of the Tests In order to enable the reader to evaluate properly the results and conclusions in the rest of the paper and in the discussions following the paper, most of the information presented by the author under this heading is quoted: The testing unit was a nominal 30 in. diameter and 18 in. long centre discharge Denver Ball Mill. The ore pulp to the ball mill comprised a small portion of the normal feed to one of the fourteen City Deep 5 ft. 6 in. X 22 ft. tube mills, and the grinding media consisted of the balls under test plus other balls to give the desired load. The running time of the test-mill was divided into approximately equal periods of five days 13½ hours each. The usual procedure was to examine and make up the load

Jan 1, 1947

By Henry T. Miller

INTRODUCTION The basic purpose of this paper is to suggest procedures and practices to insure that no employee working in a uranium milling operation receives exposure to radioactive, toxic, or other materials or agents that might produce a permanent, deleterious effect upon his physical health and well-being. This program is also designed to insure that each employee can carry out his assigned duties without risk to his health or to that of his fellow workers. The assumptions underlying this program are by necessity, conservative, with emphasis being placed upon prevention rather than correction or reaction to an undesirable situation. The limits specified-either as Threshold Limit Values (TLVs), Maximum Permissible Concentrations (MPCs), or Radiation Protection Guides (RPGs)--represent both standards of best practice and those of law and regulation. The total program is envisioned as a balanced combination of occupational hygiene and radiation monitoring. This includes surveying, air sampling, personnel dosimetry, bioassay, medical surveillance, epidemiology, and training--all backed by a thoroughly tested and evaluated set of emergency procedures. The program, as presented, is keyed to the results of monitoring, surveying, air sampling, medical surveillance, and epidemiology--it being obvious that no problem can result when no hazard can be identified. The lack of an identified hazard, however, does not negate the need for such a program and prudence suggests the need for routine surveillance programs in the best-designed facility. [The Model Mill] The model mill used in this paper is that presented by the U. S. Environmental Protection Agency in its study of the uranium fuel cycle1. The model mill processes 600,000 metric tons of ore per year into 1,140 metric tons of U308 as yellowcake per year using an acid leach process. Other characteristics of the mill such as location, tailings dam design, number of light water reactors supported, and geographical location are not pertinent to this paper. The usual remote western location of these facilities produce some difficulties in delivering the required occupational medical services and is not within the scope of this paper. The operating lifetime of most mills is commonly estimated as from 12 to 15 years in actual practice; however, the U. S. Environmental Protection Agency estimated a 20-year lifetime for its model. The principal steps in the acid leach process include :2 (a) Ore is blended and crushed to pass through a 2.5 cm (one inch) screen. The crushed ore is then wet ground in a rod or ball mill and is transferred as a slurry to leaching tanks. (b) The ore is contacted with sulfuric acid solution and an oxidizing reagent to leach uranium from the ore. The product liquor is pumped to the solvent-extraction circuit while the washed residues (tailings) are sent to the tailings pond or pile. (c) Solvent extraction is used to purify and concentrate the uranium. (d) The uranium is precipitated with ammonia and transferred as a slurry. (e) Thickening and centrifuging are used to separate the uranium concentrate from residual liquids. (f) The concentrate is calcined and pulverized. (g) The concentrate or yellowcake is packaged in 208 liter drums for shipment. This process is illustrated in Figure 1.3

Jan 1, 1981

By J. H. Rushton, L. H. Mahony

Principles of fluid motion and turbulence which have been found to be of use in mixing and agitation problems are discussed, as well as suggested applications in extractive-metallurgy processes. Various types of impellers are described, together with other conditions that affect flow pattern and turbulence. The choice of equipment for particular requirements is considered, and equations for power input are given. Modern heavy-duty mixing and agitation equipment can take an increasingly important part in such extractive-metallurgy processes as solids handling, crystallizing and leaching, chemical operations, and flotation. Application of mixing and fluid-mechanics principles to extraction methods can lead to greater process rates and a resultant saving in time and money. MIXERS are being applied with increasing frequency to problems in the metallurgical industries. The increase represents in part the modernization of mechanical equipment used through the application of unitized drives, modern electric motors and speed reducers, and recently developed materials of construction. Some applications have resulted from process changes and the use of techniques for operations similar to those that have been demonstrated and proven in the chemical industry. Still more applications are being developed through the use of fluid-dynamics principles not previously recognized as applicable to these operations. It is the purpose of this paper to describe those principles of fluid motion and turbulence which have been found to be of use in mixing and agitation problems, and to suggest applications for them in the extractive-metallurgy processes. Modern mixing equipment has been designed to provide the fluid motion consistent with that best suited to different operations.' When properly applied, these more efficient fluid-handling mixers result in lower process-production costs. Metallurgical operations usually involve large amounts of solids. The characteristics of the ore control the process and only enough liquid is added to provide sufficient fluidity for handling and processing. The reactive part of the ore, the mineral value to be extracted, is likely to be low in percentage, and the quantity of reagent required is similarly low, but excessive dilution makes additional reagent necessary and therefore is undesirable. Thus, the primary problems in minerals processing are to handle as high a concentration of solids as possible and to distribute reagents uniformly. These pulps, or slurries, are in a range of solids concentration where hindered settling rates apply, and care must be taken to agitate and mix sufficiently to maintain suspension and flow throughout the equipment. Such slurries have high densities which are the weighted average of the components and viscosities that are spoken of as "effective viscosities" but are difficult to evaluate. It is convenient to separate metallurgical operations involving mixers and agitators into three categories: solids handling, mechanical or physical operations, and chemical operations. In each of these categories fluid motion is required to maintain suspension, to distribute surface-active agents, to blend components and reactants, and to induce high rates of chemical reaction. After a discussion of some basic principles of mixing and agitation, examples of application to the three categories will follow. Fluid Motion The fundamental problems of mixing and agitation of liquids have to do with the mechanics of fluid streams and the means by which they are

Jan 1, 1955

By D. J. Carney, J. Chipman, N. J. Grant

An absolute calibration has been achieved for sampling and analyzing liquid steel for hydrogen based on Sieverts' values of hydrogen solubility in iron. Further checks were made in nickel, iron-nickel, and 18-8 stainless melts. The sampling method was successfully applied to a large number of commercial steel melts in various types of furnaces. The concurrent problem of sample storage was also solved. THE problem of sampling of liquid steel for hydrogen is more difficult than the problem of analysis. Hydrogen has a greater mobility than any other element; it is the only element that will diffuse out of steel at room temperature. In accordance with the known relation between temperature and diffusivity, the diffusion of hydrogen is extremely rapid at the temperature of liquid steel. Consequently, in the past, attempts to quench molten steel to retain the dissolved hydrogen have not been as successful as similar attempts with nitrogen or oxygen. The retention of hydrogen is especially difficult since it will continue to escape at room temperature even if the molten metal has been rapidly quenched. The hydrogen sampling methods may be classified broadly as (1) the rapid quenching techniques which attempt to preserve super saturation and (2) those methods which attempt to collect the gases evolved as the metal freezes and cools to room temperature. With all methods of sampling but especially with the rapid quenching methods, there is also a concurrent problem of storing the sample until analysis is undertaken. The two problems are interrelated and must be considered together when discussing liquid steel sampling techniques. The major obstacle in liquid steel sampling has been that there was no way of evaluating properly the various sampling and storage techniques which have been developed. It has not been possible to compare the accuracy of the various methods. For evaluation of sampling methods some known standard is required; this may be found in the published work on the equilibrium solubility of hydrogen in liquid iron which has been determined in three separate investigations.1,2,3 The data are shown in table I. Sieverts' original method of obtaining gas solubilities involved measurement of the volume of gas required to saturate the liquid metal contained in an evacuated bulb of known volume. This procedure, improved by introduction of high frequency induction heating, has yielded reproducible results which appear to be entirely dependable. Using Sieverts' method, it has been proved for iron and other metals and alloys that the hydrogen solubility is proportional to the square root of the pressure of the hydrogen gas above the liquid, so that one may work with various partial pressures of hydrogen to put different amounts of hydrogen in solution. From Sieverts' law it is possible to know accurately what amount of hydrogen is dissolved in the liquid metal at the time of sampling. The accuracy of a sampling method may be gauged by reference to this known solubility. It was the purpose of this investigation to develop a method for sampling liquid steel and for storing the sample so that the analytical result would represent the actual hydrogen content of the metal bath. For this purpose an induction furnace was

Jan 1, 1951