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By M. Schussler, J. S. Brunhouse

Arc-melted and electron-beam melted tantalum in the cold-worked and the recrystallized conditions showed high strength, good tensile ductility, and excellent notch toughness down to 321°F. Arc-melted material, containing moderate amounts of interstitials, possessed better short-time strength than higher purity electron-beam melted material up to 2000°F. Cold-working substantially strengthened arc-melted tantalum, whereas electron-beam melted material exhibited a low work-hardening rate and possessed better formability characteristics. With identical compositions and microstructures, the mechanical properties of melted tantalum and uacuum-sintered tantalum should be similar. TANTALUM metal usage is increasing rapidly in a number of applications. The outstanding chemical corrosion resistance of tantalum accounts for its applications in chemical processing equipment for severe service conditions and for surgical uses in the medical field. The largest present requirements for tantalum are in the electronics industry, where its special properties are useful in capacitors. The high melting point (5425°F) and inherent ductility of tantalum also suggest that tantalum and tantalum-base alloys might offer an excellent combination of high strength at very high temperatures and good fabri-cability. Pure tantalum has been used in significant amounts in parts requiring high-temperature strength, such as heating elements, reflectors, and heat shields in high-vacuum high-temperature furnaces and in electronic tubes. A few very promising tantalum-base alloys have been developed and are being investigated extensively. The possibilities for tantalum as a high-temperature structural material, either unalloyed or alloyed, will become better defined when more extensive mechanical property data are known. pughl measured the tensile properties of vacuum-sintered tantalum in sheet form for the temperature range of 78" to 1500°K (-321' to 2240°F), and Bechtold reported data obtained at low temperatures.' Drennen3 determined creep and stress-rupture properties of both vacuum-sintered and arc-melted tantalum sheet at 1200 °F. Some additional data on the mechanical properties of tantalum at temperatures up to 5000 °F have been summarized elsewhere.4'5 It is probable that large structural shapes of tantalum, either unalloyed or alloyed, can most readily be produced from ingots prepared by melting. Consequently, the present investigation was undertaken to determine more extensive short-time mechanical properties of tantalum metal consolidated by melting. EXPERIMENTAL PROCEDURE Melting and Fabrication—Two tantalum ingots were utilized in this study to obtain information on the effect of interstitial elements on mechanical properties. Both ingots were melted from Union Carbide Metals Co. tantalum dendrites.

Jan 1, 1961

By C. L. Burrill

The forecasts presented in this paper constitute an attempt by the writer to predict the pattern of the consumption of petroleum products in the United States during the period of transition from war to peace. Although, in preparing the estimates, secular trends were not overlooked, greater emphasis was placed upon considerations of a cyclical character, or upon influences which might be peculiar to parts of the period. The estimates do not extend beyond the year 1950 because by then conditions in the industry should have returned to normal. The consumption of petroleum products is affected, of course, by changes in the condition of business in general. Before estimates of petroleum consumption could be prepared, therefore, it was necessary to predict the pattern of general business during the period under review, particularly the economic series that in the past have shown the closest relationships with petroleum consumption. It is the writer's view that business activity in this country (as measured by industrial production) will be higher on the average during the period between the end of the war and the year 1950 than it ever was before during a peacetime period of the same duration. When the war is over, consumers will have saved amounts of money that will be very large as compared with any previous accumulations. There is little question, therefore, as to the financial ability of consumers to purchase goods. The production of many durable consumers' goods, such as automobiles, refrigerators and radios, has been completely stopped since early in the war; also, many semidurable and nondurable consumers' goods have not been available in the quantities or the qualities desired. There is considerable needi therefore, for consumers to purchase goods after the war. The important question is whether consumers will purchase goods in "1arge enough quantities to keep our economy running at a high level. The writer answers this question in the affirmative. The mere existence of very large consumer savings lends considerable support to this view because, with such backlogs of " security," consumers can afford to spend more of their current earnings than they otherwise could. Also, several polls have been taken, which indicate that consumers expect to buy large quantities of a variety of goods. Some of the savings, therefore, probably will go into current consumption. Even though this percentage is relatively small, so that the bulk of the funds accumulated by consumers during the war continues to remain as savings during the period under review, spending should be great enough to start the production cycle and keep it

Jan 1, 1945

By M. Jackman

"Froth stability is critically important for an effective separation of fine and ultrafine particles using column flotation. While a desirable froth stability is required to facilitate the drainage of entrained gangue particles for secondary cleaning, excessively stable froths could create problems in separation efficiency and down-stream processing. In this work, we demonstrate that a stable foam was produced using a poly (N-isopropylacrylamide) (PNIPAM) solution at the temperatures below the critical solution temperature. In contrast, very little foam was produced at the temperature above the critical solution temperature (~32 oC) of PNIPAM. We can also tune the foam stability by changing the temperature of wash water. When warm water of temperature of 50 oC was applied, the foam collapsed and diminished. This is probably attributed to the switching of PNIPAM molecules from coiled to a globule conformation as the temperature is increased. Our results indicate that the foamability and foam stability can be tuned by tempartureresponsive PNIPAM. This is the first time that thermo-responsive PNIPAM has been shown to have potential as a modifier of froth stability in column flotation.INTRODUCTIONIn mineral processing, column flotation has become a more prevalent process in the separation of fine mineral particles (typically < 100µm). Traditional flotation cells are sometimes less efficient in selective separation of ultra-fine particles (Kohmuench et al., 2009). The efficiency of flotation columns is dependent on the froth stability at the top of the cell to drain the unwanted gangue particles entrained in the froth. The greater froth height in flotation columns, compared to mechanical flotation cells, gives a longer froth residence time, allowing more of the drainage process to take place before the froth reports to the launderer. Secondary cleaning, by applying a wash water shower to the froth, enhances drainage of gangue particles entrained in the froth, and improves the recovery of the targeted minerals (Finch et al., 2007).While a stable froth is desirable to facilitate drainage of entrained gangue particles, greater amounts of fine particles have been found to contribute to excessively stable froths which could create problems for down-stream processes (Bethell et al., 2012). Operators have tried spraying additional wash water on the froth, and reducing frother dosage to destabilize the froth and to prevent backup at the launderer. The former is sometimes inefficient, and the latter results in unacceptable recovery loss. Currently, the best practice is often the installation of larger froth launderers, adding expensive defoaming agents, and/or using deaeration tanks (Bethell & Luttrell, 2005)."

Jan 1, 2016

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

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

Jan 1, 1952

By C. L. Clark, J. Russ

For many years attempts have been made to develop a laboratory test that would serve to indicate the proper temperatures to be used in the various hot-working applications to which metals may be subjected as they are being processed from the cast ingot to the desired finished products. That these attempts have not been very successful is indicated by the fact that most of the temperatures in use today in these operations have been developed over a period of years by trial and error. In other words, the selection of the proper temperatures for the hot-working of metals is generally an art rather than a science. Our knowledge with respect to the behavior of metals at elevated temperatures has been greatly extended during the past several years. While most of the work in this field has been done at proposed operating temperatures of equipment, rather than at processing or fabricating temperatures, one outstanding fact has been developed, which is applicable to the entire high-temperature range; that is, that the rate of deformation to which the metal is subjected is of the same order of importance as the temperature. The failure to properly recognize this fact has greatly retarded the development of a suitable laboratory test for determining hot-working temperatures. Influence of Rate of Deformation on High-temperature Properties It is not the intent of this paper to survey all the work that has been done On the effect of deformation rate On the properties of metals. The importance of this factor, however, was shown by Zay Jeffries&apos; as early as 1919, when he called attention to the existence of the so-called equicohesive temperature and to the effect of certain factors on the location of this temperature&apos; Fig. I is a diagrammatic sketch showing the effect of temperature On the relative strength of the crystals and grain boundaries and the type of fracture that will res depnding On the location of the test, or Or temperature with respect to the equicOhesive temperature. Since the type fracture varies, it also follows that at temperatures below the equicohesive temperature the major deformation occurs in the grains: while at temperatures above, the deformation results either from the movement of the grains with respect to each other or recrystallization of the strained material occurs almost instantaneously, producing new crystals at the fracture. As previously indicated, it is an established fact that the position of this equicohesive temperature for any given metal is dependent On the deformation rate&apos; For example, in 0.15 per cent plain carbon steel the location of this temperature under

Jan 1, 1947

By Changmiao Liu, Dong Dong

"Magnesite is a major mineral resource in China, whose output and export are massive and quite important to the world. Flotation performances of eight anionic collectors on magnesite were studied to find the proper ones. Micro-flotation results indicated that collectors of HOl, SDBS and AEP had outstanding flotation performances on magnesite, with the recovery ratio all reaching above 90% in a wide range of alkaline pulp. Solution chemistry calculation, Zeta potential and FTIR measurements were employed to reveal the interaction mechanism between anionic collectors and magnesite surfaces. Solution chemistry analysis indicated that the main active components of HOl, SDBS and AEP were anions and association complex anions in alkaline pulp. Magnesite surface was negatively charged in the alkaline pulp. The active sites on magnesite surface were mainly the components of MgOH-, Mg (OH)2, and MgCO3 when the pulp pH was over 8. Anionic components of HOl, SDBS and AEP reacted with Mg in magnesite surface to make the insoluble anionic salts. And the chemical adsorption was confirmed by the FTIR measurement evidences.INTRODUCTIONAs an important industrial mineral, magnesite has been widely applied in metallurgy, building materials, chemical industry, agro-pasturage and other fields (Hu et al., 2006). It is a major mineral resource in China with abundant reserves. Its output and export are massive and quite important to the world. Liaoning province is rich in magnesite, whose reserves and production both come first in China. So far the proven reserves have reached 2.91 billion tons, accounting for more than 90% of total reserves in China, and more than 25% in the world (Li et al., 2012).Magnesite ores in Liaoning province mainly contain crystalline magnesite, and the gangue minerals of quartz, dolomite, talc, tremolite, chlorite and carbonaceous materials. Some ores also contain a little pyrite, chalcopyrite, hematite and apatite. Most of the ores must be preprocessed to separate the useful parts from the large amount of gangue minerals, so that their value and industrial application can be enlarged and promoted.Flotation is commonly used to process the magnesite ores, and the conventional flotation methods include anionic and cationic flotation. In the former, gangue minerals of silicates were separated by using amine type cationic collectors. After the impurity minerals were removed, high qualified magnesite concentration could be gained. For the cationic flotation method, it had some drawbacks of lower recovery ratio and poor performance in the lower temperature pulp (Li et al., 1995)."

Jan 1, 2016

By Phillip B. Bucky, Fred D. Wright

The present known petroleum reserves are limited, and unless important new fields are discovered the Nation will be dependent, in the not too distant future, upon imports or upon synthetic liquid fuels to supplement domestic petroleum supplies. As a national defense measure, it would appear desirable to develop a substitute source of liquid fuels within the borders of the country if new discoveries of petroleum should Prove disappointing. Congress undoubtedly had this in mind when it passed the Synthetic Liquid Fuels Act (78th Congress, approved April 5, 1944). The act directed the Bureau of Mines to construct and operate demonstration plants for producing synthetic liquid fuels from coal and oil shale, and from forestry and agricultural products. As a part of this program, the Bureau of Mines has built a demonstration plant at Anvil Points, near Rifle, Colo., for retorting the oil shale, and has developed a mine to supply the plant with oil shale. At the beginning of mining operations, the physical qualities of the oil shale, which would have a bearing upon the selection of mining methods and practices for exploiting the deposits, were largely unknown. A comprehensive mining-research program has been set up to determine the best methods and practices to follow to obtain the lowest overall practicable mining cost for producing the oil shale on a large scale. Unusually low mining costs will be necessary for shale oil to be produced commercially. Consideration now is being given to exploiting a series of flat-lying beds 70 ft thick by a room-and-pillar method of three benches with the advance heading at the top. This report is one of a series giving the results obtained in research on mining problems, The structure and physical qualities of the oil shale indicate that the 70-ft interval of the oil-shale measure can be safely mined in open stopes; studies indicate that this method would be the most economical one to use.&apos; As labor will be a major item of expense, the largest equipment that could be operated efficiently in the workings would be required to obtain the lowest practicable mining Cost. It Was therefore desirable to know the maximum safe span of unsupported rooms and the size of pillars necessary to support the overburden. This paper describes the work done at the Columbia School of Mines Barodynamic Laboratory in determining the maximum safe unsupported roof spans and the minimum safe pillar dimensions for the oil-shale mine at Rifle, Colo.

Jan 1, 1949

By R. L. Whitting, George Fancher

A typical drilling mud from the Hastings oil field, Brazoria County, Texas, containing only 8 per cent (dry basis) of material of colloidal dimensions, which is largely illite, was concentrated to a density of 10.2 lb. per gal. and used in this study. The effects of water dilution, treatment with complex polyphos-phates, temperature and the time of heating upon the rheological properties of the mud were investigated. It was found that water plays an important part in chemical treatment and that sodium acid pyrophosphate and sodium tripolyphosphate were more efficient than other complex polyphosphates for chemical treatment. Muds treated with either of these chemicals manifested maximum reduction in viscosity and minimum filtration rates at low concentrations. Furthermore, .mud treated to minimum viscosity with either of these two chemicals was virtually unaffected by heat-treatment. Introduction The drilling of deep wells is dependent upon the use of drilling mud, and problems frequently arise concerning the effects on mud of temperature, prolonged heating and aging. The use of chemicals to control the rheological properties of mud is a well-established practice. Salts of weak organic acids such as sodium tannate or gallate were used at first until the complex phosphates of sodium were found to be more efficient. Consequently, it seemed important to investigate the reaction of a mud to chemical treatment with phosphates, temperature, heat-treatment and aging, particularly since previous work in the laboratory at the University of Texas had provided the particle-size distribution and mineral composition of Hastings mud. Properties or Mud Used in Experiments A large sample of the mud from a drilling well in the Hastings field, Brazoria County, Texas, was obtained directly from the circulatory system. Some of the general physical characteristics of the mud and other data are presented in Table I. Table i.—General Properties of Hustings Drilling Mud Alex- Cur-ander keet Well Well Depth when sample was taken, It.. 5720 5700 Weight. lb. per gal............... 9.5 0.8 Viscosity, sec. A.P.I.............. 47 60 Viscosity, Stormer, grams......... 80 Viscosity, centipoises............. 13 Filtration rate, c.c. per 30 min.a. . . 19.6 22.8 Salt content (chlorides), per cent... 0.13 0.12 pH............................. 8.9 8.9 The Alexander mud was used for the experimental work. Comparison with Curkeet mud indicates a considerably greater dilution but otherwise suggests similarity. The mineral composition and particle-size distribution of Curkeet mud (Table 2) are available (Fancher and Oliphant6). It is suggested that Alexander mud would have a similar composition.

Jan 1, 1943

By H. M. Otte

Certain choices for the shear elements of the inhomogeneous distortion in the phenomenological theory of martensite formation are examined for their agreement with crystallographic and X-ray data of iron alloys. The assumption that the shear elements must represent slip or twinning systems characteristic of bcc metals is found to covey all observations, even when a small uniform dilatation is taken into consideration. In bct martensite, (011) becomes a possible twinning or faulting plane, in addition to {112), and qualitatively similar X-ray line broadening is to be expected from both. The basic concept inherent in the current theoriesl-4 of the formation of martensite is that the interface between the parent (austenitic) and product (martensitic) phase is an invariant strain plane (i.e., one that is undistorted and unrotated). Experimental evidence that the interface is of such a nature is available in certain transformations2&apos;5&apos;6 but for the transformation in iron alloys direct observation has not proved enlightening. Internal strains resulting from the formation of the small martensite platelets within the parent austenite matrix7 make it difficult to produce the desired evidence. Indirect evidence, however, such as the continuity of scratches in passing from untrans-formed to a transformed region, strongly indicates that the habit plane in iron alloys is an invariant strain interface. The scatter in habit planes in a given specimen8 would suggest that internal stresses have a slight but definite influence. On the other hand, composition changes which affect the lattice parameter can alter the habit plane appreciably, and by an amount greater than the scatter.&apos; The success of the theories depends on the choice made for the "inhomogeneous distortion" or "complementary shear&apos;&apos; in the analysis and also on the choice for the parameter 6 representing a small uniform dilatation. In the approach developed by Wechsler, Lieberman, and Read&apos;," it is implicitly assumed that 6 is unity. In the case of iron alloys, all observations cannot be explained without varying either the inhomogeneous distortion or 6 . Bowles and Mackenzie3 considered only the effect of varying d. They found it difficult to reconcile the wide scatter of habit planes with the theory and were forced to the conclusion that it may also be necessary to consider variations or different choices of the inhomogeneous distortion. Wechsler and Read" considered a limited number of possible choices for the inhomogeneous distortion, but no variation in 6, though this could easily have been introduced if so desired. It is the purpose of the

Jan 1, 1961

By Nelson R. Shaffer

Glamorous, burgeoning biotechnology and mundane industrial minerals would at first glance seem to share little in common, but in truth, modern biotechnology depends on many minerals. Biotechnical processes also can be used in industrial mineral extraction and processing. Biotechnology is broadly defined as the application of biological organisms, systems, or processes to manufacturing and service industries. Genetic engineering has reinvigorated one of mankind&apos;s oldest sciences, biotechnology, into a booming business. Many modern processes depend on microorganisms cultivated under very stringent conditions in bioreactors. Minerals from carbonate, sulfate, chloride, nitrate, phosphate, and silicate families are used to provide essential nutrients and to regulate growth conditions (such as pH) in order to assure optimal growth of organisms. Certain cells or enzymes perform better when immobilized upon or within solids, and minerals are often used to immobilize cells, especially in continuous process. Minerals are also used extensively in separating and purifying products of biotechnology. Diatomite, zeolites, and silica are especially useful in purification processes. Industrial minerals also are commonly used to clean up large volumes of process water that must be treated. Biotechnology can be employed in exploration, extraction, and processing of geologic materials and in reducing mining or other environmental problems through bioremediation. Microbes have been shown to solubilize certain elements and so promote extraction of heavy metals, phosphate, aluminum, potassium, and even rare earth elements. In a related technique, unwanted materials such as pyrite impurities can be leached microbially to produce cleaner products in sand and clay industries. Microbial actions can modify surface characteristics and so enhance certain ceramic properties. Certain organisms can accumulate useful elements from dilute sources; others can transform unusable chemical species to more useful forms. Deterioration of stone, concrete, and even glass or brick, can be accelerated by microorganisms. Control of such biodeterioration could improve long-term performance of industrial mineral products. Microbial processes have shown promise in improving several mine-related problems. Certain bacteria help remove clays from phosphate slimes and other suspensions. Others are used to degrade cyanide or other organic chemicals such as floatation aids. Cells immobilized on clays have been especially efficacious in bioremediation. Biotechnology industries, like the industrial minerals industries, encompass huge ranges of materials and processes. Costs of products from these industries range from pennies to thousands of dollars per unit, and their products are vital for maintaining modern life styles. Many biotechnical processes depend upon industrial minerals and certain biological processes can be harnessed to do useful tasks in the minerals field. The interplay of industrial minerals and biotechnology is important today, and as biotechnology advances, its interaction with the industrial minerals industry can only increase.

Jan 1, 1995

By Norris Johnston, Carrol M. Beeson

For many years the permeability of reservoir sands has been measured by flowing air through a cleaned and dried core sample. This differs from the true reservoir permeability in one important respect: the rock particles in the reservoir are surrounded by interstitial water, not air, and their physical shape and condition of hydration are greatly dependent thereon. Permeability as defined must be measured with a single-phase fluid. Since no means exist for removing the oil and gas from a core sample by simply flowing water through it, the sample must be cleaned and then resatu-rated with water before testing. The present discussion attempts to show that after the cleaning process a considerably different permeability is determined with salt or fresh water than is obtained with air. The postulate is made that the salt-water permeability is probably closer to the true reservoir permeability than is the measurement with air. This is discussed in relation to both physically possible and economically feasible measuremerits. Data On more than 1200 core samples are given to show the nature of the effects observed, and a plea is made for others to consider water permeability measurements as a routine necessity, eventually replacing air permeability in regions where the differences are great. Introduction Permeability is defined1 as a "a measure of the capacity of a porous medium to transmit fluids, when there is no interaction between the solids and the fluid." Darcy&apos;s law of liquid flow in porous media states: kA?P QµL/A?L [I] where Q represents milliliters of liquid of viscosity p centipoises passed per second through a porous medium of permeability k darcys and cross-sectional area A sq. cm. under a pressure gradient ?P/L atmospheres per centimeter, the flow being understood to be laminar or viscous, not turbulent. This equation defines the darcy. For the case of radial flow in a uniform sand, such as usually exists in the neighborhood of a well in an oil or gas sand, Darcy&apos;s law becomes:2 Here h is the net sand thickness in feet, Pe and Pw are pressures at the drainage radius4 and well radius, and re and rw are these radii, respectively. The productivity index3 is defined as the barrels of liquid produced per day per pound per square inch mean pressure differential between ferences and well bore, and is thus: By further definition, the specific productivity index is: or in terms of practical units, and allowing for shrinkage:

Jan 1, 1945

By John Brown

As a part of a symposium on the relations of structure to ore deposi-tion, in February 1938, the writer presented some tentative opinions derived from his experience with a number of important lead-zinc replace-ment deposits. These ideas were set forth, as a basis for discussion and a stimulus to further inquiry, in a mimeographed leaflet that read as follows: Intimate acquaintance with a number of lead and zinc deposits in metamorphosed limestones seems to indicate the existence of certain common features from which can be established some general principles governing the localization of ore in this type of formation. It is suspected that these principles can be applied, with modifica-tions, to mineralization in unmetamorphosed limestone. In metamorphosed forma-tions, some observed rules are as follows: 1. Bands or masses of pure limestone are very resistant to replacement by ore solutions, and are likely either to contain no ore or to resist replacement until near the end of mineralization. The reason for this apparently is physical, not chemical, since microscopic data indicate that when ore is deposited by far the greater part of it substitutes for carbonate. The chief factor is believed to be a lack of porosity in massive limestone that has undergone flowage and recrystallization. 2. Masses of intensely siliceous or silicated rock are likewise unfavorable ore receptacles. This seems to be accounted for by two factors: (a) chemical unsuit-ability or resistance to replacement, and (b) physical resistance to small-scale brecci-ation, which might facilitate the opening of effective channelways for solutions. Some low-grade ore may occur, however, and also sporadic fracture fillings. 3. The optimum condition for ore reception appears to be found in bands or areas containing carbonate and silicates (or quartz) intimately mingled in something like equal proportions. In this situation movement is likely to result in mixed flowage and fracture, producing a fine-textured porosity that admits solutions freely and provides access to an abundance of replaceable carbonate. Cleavage cracks in some minerals such as diopside are believed to facilitate the penetration of solutions. 4. Certain minerals or assemblages are regarded as favorable impurities in a lime-stone and others as unfavorable. Original quartz, and subsequently developed diopside, and perhaps garnet, are typical favorable pre-ore gangue; in general rather equidimensional, brittle minerals. Tremolite, biotite, and probably wollastonite, are typical unfavorable pre-ore gangue; in general highly elongated and somewhat flexible minerals likely to develop under strong shearing stresses. 5. Tentative opinion is that the ratio of lime and magnesia in a limestone-is of little or no importance.

Jan 1, 1940

By M. H. Waxman, M. Gondouin, H. J. Hill

Streaming-potential experiments were conducted within the Muddy- and Dakota-sandstone interval of a Denver basin well. Analysis of the data shows that, for this case, streaming potentials opposite sands were higher than those opposite shales when the mud was fresh. Streaming potentials opposite shales, however, were of sufficient magniiIlde to be important in SP interpretation. They were linearly dependent upon pressure differential, and they increased with mud filtrate resistivity. The magnitude of streaming potentials opposite sands was influenced by the characteristics of the original mud cake formed at the time of drilling. Use of mud samples taken at the time of logging may not always be satisfactory for determining streaming-potential corrections. Both the streaming and electrochemical potentials were found to be affected by the previous history of the borehole system. Following a change in mud characteristics, several days were required for SP stabilization. This was, in part, due to the mud cake acting as an imperfect shale membrane. INTRODUCTION Laboratory investigations by Wyllie,1 Salisch,2 Moore," Sen Gupta and Bannerjee,0 and Hill and Anderson&apos; have shown that streaming potentials developed across mud cakes deposited on permeable filter beds are of sufficient magnitude to be critically important in SP interpretation. Streaming potentials across shales have been reported by Schenck,&apos; Gondouin and Scala; and Hill and Anderson." The magnitude of the shale streaming potentials obtained by Schenck and by Gondouin et a1 led these authors to conclude that in many cases the shale streaming potential would approximately equal the mud-cake streaming potential. Hill and Anderson, however, obtained somewhat lower magnitudes of shale streaming potential. The field experiment described in the present paper was a cooperative project carried out by the respective operations and research departments of Schlumberger Well Surveying Corp., Shell Development Co. and Shell Oil Co. The primary objective of the experiment was to determine in the borehole the streaming-potential behavior of both shales and mud cakes under conditions approaching, as nearly as possible, those normally encountered in logging practice. METHODS AND EQUIPMENT WELL A Muddy- and Dakota-sandstone vie11 in the Denver basin was chosen for the experiment. Both sandstones were water-bearing and, since reservoir pressures in these sandstones are abnormally low (gradient of approximately 0.25 psi/ft), it was expected that studies of streaming potential could be conducted from low-pressure differentials (approximately 200 psi) to about 27000 psi by bailing mud from the hole, filling up and then applying wellhead pressure. The selected well encountered the Muddy sand-

By D. R. Packard, J. D. Verhoeven

The resistivity us atom fraction relationships for dilute solutions of cadmium, mercury, and tin in molten sodium have been determined. With these data and the resistivity capillary-reservoir technique, the electro-transport mobilities, effective valences, and the diflusion coefficients of the three solutes have been determined. The mobilities are found to be higher than in other molten alloys by a factor of around 20. The results are compared to the Mmgelsdorf model for electrotrmtsport. The high values found for the mobility to diffusion coefficient ratio indicate that small quantities of the alkali metals should be susceptible to purification from many solutes by means of electrotransport. PASSAGE of a direct electric current through a liquid metal containing a solute will usually cause a relative motion between the solute and solvent atoms of the alloy. This electrotransport phenomenon may be described experimentally in terms of the mobility of the solute atoms, i.e., the drift velocity of the solute relative to the solvent per unit electric field. In dilute solutions of liquid alloys this relative mobility becomes a measure of the velocity of the solute with respect to the observer since the motion of the solvent is negligible. The mobility is a significant parameter in evaluating the potential usefulness of electrotransport for such things as purification or solute control upon solidification. Prior to around 1958, quantitative data for the mobility of solutes in liquid metals were restricted to some solutes in liquid mercury. Since that time ad- ditional data have been reported for the mobility of solutes in liquid mercury, bismuth, tin, and lead, as shown in Table I. In 1963 Drakin et al.11 reported some values of a transport number for mercury and thallium in molten sodium and potassium. When these values were converted to mobilities, it was found that the mobilities were higher than any of the previously reported values by a factor of around 20, as shown in Table I. Drakin&apos;s experimental technique did not eliminate the presence of back-diffusion and consequently his data were expected to be lower than the true values. The purpose of the present investigation was to determine the mobility of a number of solutes in molten sodium with an experimental technique which eliminates back-diffusion errors. EXPERIMENTAL The technique used to determine the mobility was a resistivity capillary-reservoir technique which had previously been used with a high degree of precision on Sn-Bi alloys.4 This technique consists of dipping the vertical Pyrex capillary cell shown in Fig. 1 into a molten bath of alloy while the bath and capillary are under vacuum. The capillary is then filled by intro-

Jan 1, 1969

By 1928-05-01

"The carnotite ores of Colorado and Utah were the chief source of radium for many years. In the fall of 1922; news of the very rich deposits of radium ore discovered in the Belgian Congo caused almost complete cessation of domestic production. The Congo ore contains pitchblend and a number of alteration products, including the new minerals bequerelite, curite, kasolite, stasite, and dewindite. Reports indicate that a considerable amount of ore containing over 50 per cent U308 has been produced. It seemed certain that radium could be extracted from the Congo ore at a much lower cost than from the relatively low-grade carnotite; and in order to preserve their elaborate marketing organizations, the larger American producers made agreements with the Belgium syndicate to market the foreign product in this country. The price of radium has been held at $70 per milligram. Extraction of radium from carnotite by the usual methods does not appear to be profitable at that price. With one exception, all American firms ceased production after their accumulated stocks of ore had been treated. The United States Radium Co., which continued to treat carnotite for several years, has recently shut down its plant.Although there is probably a large profit derivable from the treatment of Congo ore, it is not likely that the Belgium Syndicate will meet sufficient competition to cause any reduction in the present quotations. It is not known how long the high-grade ore will last, but when exhausted the price of radium may be expected to advance. According to K. L. Kithil3 it is the opinion of interested parties that, so far as can be forseen, radium will in future years never again be obtained at the present low price.Carnotite contains the valuable element, vanadium, which is not present in the Congo ore. The recovery of-vanadium is an important factor in the cost of extracting radium from carnotite, and under favorable conditions carnotite can be profitably treated for the vanadium alone. Vanadifecous sandstones are found ranging all the way from roscoelite (vanadium mica), containing little or no uranium; to a high-uranium and low-vanadium carnotite. Ores containing 2 per cent or more U308 are classed as radium ore and are sold on the basis of the uranium content, which is proportional to the radium content. Only in exceptional cases have ores been evaluated on the basis of both the radium and vanadium contents, although the presence of vanadium has undoubtedly influenced the price of radium ore."

May 1, 1928

By A. A. Collins

OF widespread interest to all lead metal¬lurgists is a dross smelting process that will consistently give mattes and speiss of low lead and high copper contents. It is -a problem that has intrigued operators through the years. In the past few years, with increased amounts of copper and overcrowded metallurgical furnaces, it has been almost imperative to evolve some method. Experience at El Paso has shown that high copper-to-lead ratios can be consistently attained by use of the new soda process.* OLDER METHODS Three older methods; i.e., I. Dross plus siliceous ore and limestone, 2. Dross plus one fourth blast-furnace speiss and siliceous ore, 3. Dross plus sulphides and siliceous ore and scrap iron, do not give consistent results and the products are higher in lead and lower in copper than those produced with the soda process. Any radical changes in the blast-furnace drosses will throw any of these older methods into a tailspin. For almost ten years, El Paso used the third method, with varying results. It was noted that as the arsenic and antimony contents of the dross increased, the speiss and matte steadily increased in lead and decreased in copper. A dross containing four parts of copper to one part of arsenic was considered to be ideal. At times this balance of copper to arsenic was almost impossible to obtain, especially when handling copper Cottrell dusts, which vary so greatly in copper and arsenic. Custom smelters like El Paso, handling a great variety of dusts, concentrates and ores, are apt to have anywhere from 1 to 15 pct copper on charge, with a variable in arsenic of from 0.5 to 2 pct. With such conditions, and drosses varying from 12 to 40 pct copper, an operator using the older dross reverberatory practices would find it just about im¬possible to control the reverberatory operations and to produce a good product low in lead and high in copper. These conditions prevailed at El Paso from the year 1940 to the present. In May 1942 it, was decided to experiment with the soda process. THE SODA PROCESS After considerable work the soda method was finally evolved to the present state. It has never failed to produce a good product even under the most adverse conditions. It might be well to remember that many men of thought in the smelting industry have at one time or other suggested the removal of all copper, arsenic and antimony from the lead blast-furnace charge as an aid to better metallurgy.

Jan 1, 1947

By E. H. Rose

The present symposium on flotation machines provides a unique opportunity for group reappraisal of standard or habitual viewpoints. A symposium is by definition a trading post- for observations that might prove complementary when put together, thus leading to useful thoughts that might not have been evident from the original observations individually. The present paper, pertaining to power consumption in flotation, is deliberately an experiment of that kind. Data were solicited from the operating superintendents of several of the major flotation plants on this continent. The information received, covering a total of 14 separate operations in seven plants, has been collated in terms of power intensity; that is, the total power input per cubic foot of cell volume. This departs somewhat from the conventional expression of power per ton of ore treated, though the latter figure is also given for the plants concerned. Because of wartime restrictions, particularly in Canada, identifying names of plants and machines are withheld. Not as a firm conclusion, but as a tender for symposium discussion, the following points are made: 1. That flotation is a power operation in much the same sense as ball milling. 2. That contact time is the complement of power intensity and may be decreased as the latter is increased. 3. That a decrease in flotation power per ton of ore can result from an increase in power intensity. Analogy with Grinding In grinding, it has become axiomatic that the more the power put into a given operation, the greater the work performance. The analogous view is now proposed that the effectiveness of any flotation operation will be related to the mechanical energy usefully applied to that operation. Under this view, each increment of properly directed input energy should give either an increase in unit tonnage or an improvement in the metallurgical separation (concentrate grade or tailing grade), until either the theoretical limit imposed by mineral constitution or surface condition is reached, or until further increments of power become uneconomic under the law of diminishing returns. Thus, as in grinding, there are two forms of output that greater power input or improved utilization of power can produce. As for the law of diminishing returns, lower unit cost of power through improved generating efficiency in the past decade has pushed the limit back. Over and above this, however, there is strong indication in the operationg data herein presented that higher power intensity results in an actual economy of over-all power consumption. Like crushing and grinding, flotation accomplishes a rupture of the forces of molecular attraction, by taking particles from the common environment and placing them in the two separate environments of

Jan 1, 1947

By Irving M. Symonds

Compania Minera de Penoles, S. A., at its Avalos unit operates a lead-zinc concentrator having a capacity of about 600 short tons per day. Lead and zinc concentrates are made by flotation methods. The concentrator is at Terminal de Provi-dencia, in the state of Zacatecas, some 70 miles south of Saltillo, Coahuila. The Penoles-Avalos railroad operating between the plant and Estacion Avalos, a distance of 6 miles, makes connections with the Coahuila and Zacatecas railroad, which in turn connects with the Nacionales de Mexico at Saltillo. The three railroads are each of different gauge, requiring the transfer of all supplies and concentrates at each junction. The mill operates on company ores, on ores from leased mines, and as a custom mill. The custom business is very small. The lead concentrates are shipped to company smelters at Monterrey, Nuevo Leon and Torreon, Coahuila. Since the European war, all zinc concentrates have been shipped to the United States. Ore Treated The major source of ore supply is a group of four mines owned or leased by the company, some three miles south of the mill in the mountains, from which the ore is delivered to the mill by a gravity aerial tramway. Custom ore comes in by rail. The ores occur in chimneys. The upper levels contained oxidized siliceous ores of lead, copper, silver and gold, with varying amounts of zinc. These ores were direct-smelted. In the first two years of operation a good deal of the tailing loss was caused by the oxidized content of the ores milled. Much of the ore in the transition zones between the oxides and sulphides was not mined. The ores now being milled are clean, hard sulphides in a limestone gangue, with only occasional contamination of oxides. The lead and zinc sulphides are of coarse structure and are freed even above flotation sizes. The galena is usually "steel" colored, easily and quickly floated. When there is any oxidation, it is usually on the coarsest crystals. The zinc minerals vary a good deal in color; a resin sphalerite predominates but there are varying shades of brown marmatites. On an average, the zinc sulphides contain 64 per cent zinc. The only common copper mineral is chalcopy-rite. Little is known of the occurrence of gold and silver. Waste minerals are mainly limestone and pyrite, both of which are barren. The ores vary from 20 to 35 per cent pyrite. Mill heads for the year 1940 and the first eight months of 1941 are given in Table I.

Jan 1, 1943

By Christopher R. Davis

Resource modelling is the basis for any economic appraisal of a mining project and includes a number of steps from data acquisition and validation to resource reporting and classification. At each step in the modelling process it is necessary to define the specific objectives, the methodology proposed to achieve those objectives and to establish a set of checks and validation tools to assess the effectiveness of the proposed methodology. The data used has to be both reliable and relevant for the purpose of the modelling. QA/QC for database validation requires verification of sample location; including correct collar location, topographic modelling and down-hole surveying. Validation is also performed on assaying information such as checks for sampling bias and accuracy of core splits, proper use of pulp duplicates and standards, handling of calculated values, explicit/implicit absent data and data entry errors. The second step involves identifying the mineralized domains resulting from the mineralization process. This step requires a geometric interpretation of all relevant geological features that have influenced the spatial distribution of the mineralization including dykes, faults and alteration. In addition, a geologic reference system rather than a standard Cartesian system is established to measure distances between samples. Once the mineralized domains are established and the database has been validated, statistical and spatial description of the mineralized samples are examined in order to establish the histogram and the variogram of all variables of interest and their correlation. Results are also used to calibrate the global resource estimate within the mineralized domain and to establish the search strategy for grade interpolation. The mineral envelope is filled with polyhedral cells representing mining blocks. The average grade of these blocks is estimated using kriging techniques in order to eliminate global bias and to minimize the local error in the block grade estimate. Visual checks are made to validate the spatial trends in grade distribution while global bias and smoothing effect are assessed from the declustered sample statistics. When required, smoothing correction may be applied using ?change of support? techniques. Simulations are used to perform sensitivity analysis and the simulation models are used if severe smoothing of spatial variability makes the interpolated model inappropriate for mine planning. The keys to successful resource estimation are an integrated team of geologists, geophysicists, geostatisticians and mine engineers using the best available technology and reviews by independent auditors. The resource team is also responsible for performing a QA/QC program in order to measure the effectiveness of the methods in meeting the specific objectives at each step of the modelling process.

May 1, 2001

By J. Fred Johnson

COROMANT is the trade name of the alloy-steel drill rod tipped with a chisel-type tungsten-carbide bit manufactured by Sandvik Steel Works Co., Ltd. Other names, such as Swedish or air-leg method of drilling, are used in various localities. Coromant drilling in Sweden was the natural sequence of the adaptation of tungsten-carbide inserts to the already established routine of drilling. By the middle thirties the percussion drill had reached practically its highest attainable efficiency as a drilling machine. Since then improvement has been in metallurgy of component parts to increase life or lessen weight, in the development of pneumatic and automatic feeds, in the use of jumbos to more quickly and easily handle machines, and in changes in drill rods and bits. By 1937, drilling in the United States and Canada was done by relatively heavy mounted drifters with positive hand or automatic feeds. In Sweden, on the other hand, emphasis had been placed on light equipment and drifting was done with pneumatic bars and reverse-feed stopers. In 1938, one of the most prominent American drill manufacturers developed an air-leg for successfully drilling the extremely variable but relatively soft iron ores of some of the northern Michigan mines. Also in 1938, a comparative Swedish test, also in soft iron ore, of a 50-lb jackhammer mounted on an air-leg, against a 100-lb reverse-feed drifter on a pneumatic bar, showed the net drilling time was increased by the air-leg set-up from 51 to 71 pct, in drilling 6-ft rounds in a 6 1/2x6 1/2 ft drift. Miners were becoming scarce in Sweden even at that time and, since the lighter equipment made the work easier and more attractive, the airleg was then made use of in some types of soft rock. In 1940, for instance, a large tunnel for a hydroelectric plant was driven with this equipment. By 1943, when tungsten-carbide inserts came into the picture in Sweden, a great many of the kinks in percussion drilling with this hard-metal had been worked out in Germany under the stress of war conditions. However, only 10 pct of the drilling machines manufactured in Sweden were jackhammers for use on air-legs and only the one manufacturer made air-legs in the United States. American practice had largely supplanted integral forging of drill bits by the detachable steel bit. Canada and South Africa were using the one-pass throwaway bit but Sweden was still using the same old integral forged bit. After a long study of the trend toward simplicity

Jan 1, 1952