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By M. E. Wadsworth, R. D. Groves, B. W. Madsen

Experimental results obtained from large-scale (7 ton), long-term (500 days) leaching of low-tenor copper sulfide ores were interpreted by a geometric model involving the movement of a reaction zone through the ore fragments. The postulated leaching mechanism involved mixed kinetics and included diffusion of the reacting species through the host rock and a chemical reaction at the surface of the mineral particles. Ore properties which were considered were Ore particle size and shape, grade of ore, and mineral content. Excellent agreement between the mixed kinetic model and the laboratory leaching results was obtained when -1/2-in. ore particles were not included in the leach. Also, a satisfactory prediction of copper recovery from +1/2-in. ore with a different particle size distribution was made; however, it was necessary to modify the shape factor in the model. Prediction of copper recovery from an ore sample which included the -1/2-in. fine fraction and leaching for 460 days was 56.5%, and the recovery from leaching was 47.0%. The presence of fines caused solution channeling and a deficiency of oxygen which inhibited the leaching rate. Also, compaction of fines around coarser particles interfered with circulation around the ore particles, and bulk solution transport probably was a rate controlling factor.

Jan 1, 1976

By J. G. Eberhort

ThE literature of surface phenomena shows that, except for most of the rare-earth elements, surface tensions have now been determined for almost every liquid metal. The situation for liquid metal oxides is, in contrast, characterized by a great scarcity of surface-tension data. A surface-tension correlation between these two classes of substances has been found which provides a means of estimating unknown liquid-oxide surface tensions from the corresponding known liquid-metal surface tension. Lf the surface tension of the liquid metal is a(M) and that of the liquid metal oxide is o(M,Oy), then oxides of all stoichiometries can be brought into one correlation if is plotted against with the surface tensions taken at the respective melting points. The available data is displayed in this fashion in Fig. 1 where the relationship between the surface tensions of the two classes of liquids is found to be The correlation in Fig. 1 is based on data found for nine liquid metal oxides and the corre- sponding liquid metals In cases where several sur-face-tension determinations were available on the same substance, higher values were generally favored over lower ones because they usually indicate greater Sample purity. All of the metal-metal oxide pairs are in good agreement with Eq. [I] except for B-Bz03. The reason for the departure of this pair from the correlation is not understood. To estimate the surface tension of other liquid metal oxides the corresponding liquid-metal surface tension must be found. A nearly complete bibliography of the surface tension of liauid elements is available in the 46th edition of the Handbook of Chemistry and physics. Some additional references on metals are included here for convenience Se,26Sr,'?ThanduZ5). It is also possible to estimate the surface tension of a solid metal oxide or metal from the corresponding liquid-state data. As a liquid material is cooled through its melting point the surface tension increases abruptly by an amount Ao. bondi' has estimated that the maximum value of Aa at the melting point is Ao = Ahf/A [2] where Alzf is the heat of fusion per atom and A is the area per atom in the interface. Thus with heat of fusion and crystallographic data the surface tension of a solid at the melting point can be estimated as o + Ao.

Jan 1, 1967

By John C. Cosgrove

IT was just five minutes past midnight, on Wednesday, Jan. 5, 1938, that Mrs. Cosgrove and I sailed from New York City. Our trip was to completely circle the globe, to cover over 40,000 miles and stop at thirty ports-from New York to Trinidad, to South America, via South Africa to the Orient, to India, to the Malay States, to Indo-China, the Philippines, Australia, New Zealand, Fiji, and across the Pacific home via Honolulu. It is not my intention to make this a complete, technical study of coal or coal mining in the various countries that .we visited but more to outline the general in- formation that the mining engineer and coal operator would absorb in his travels. Coal is the universal fuel and is in use wherever there is commerce and industry. Even on our ship, which, like practically all ocean liners was an oil-burner, a considerable quantity of coal was used for cooking.

Jan 1, 1939

By W. C. Knopf, G. Samsel

For several years International Minerals & Chem-ical Corp. has used a radiation method to assay potassium content of products from potash and feldspar beneficiation. The procedure is rapid, accurate, and inexpensive and is easily handled, if necessary, by nontechnical personnel. Data are presented to show the accuracies that may be expected if the technique is used for control of pilot plants or large-scale plants. Natural potassium is composed of three isotopes —K, K and K. Five other isotopes, artificially produced, have been detected. In natural potassium only the K isotope, with a half life of 1.4x10 years, is radioactive. Its modes of decay are beta and gamma rays, positrons, and x-rays. Only the more abundant beta rays, however, are important in radiation measurements using geiger tubes. Barnes and Salley' measured radiation of potassium salts in solution in 1943. Gaudin and Parnell2 first reported the use of solid salts arranged in a vessel surrounding the ß counter in 1948. Later, Scheel used the method to assay potassium content of various crude and finished potash salts. Experimental: Dip-type Geiger-Muller tubes (TGC-5) supplied by Tracerlab Co. were used in all radiation counting measurements. The tube was encompassed by a glass container about M in. larger in diameter than the tube. This container, which served as a sample holder, was closed at the bottom with a rubber stopper to facilitate removing the samples. Samples were not weighed, but about 40 g of sample were needed for each test. Electrical impulses from the tube were counted on either a Tracerlab scaler or a rate meter. To obviate the need for constant attendance, preset features were incorporated into the scalers, so that at a predetermined time or count the units were automatically deactivated. When rate meters were used, counting rates were read directly from instrument or from a recorder used in conjunction with the rate meter. Each tube was calibrated, according to the manufacturer's instructions, to determine the correct operating voltage to insure reproducible results. A linear calibration plot of percent K2O vs counting rate was also obtained for each tube by recording the counting rate plus background count of several standards of different K2O content chemically analyzed by the chloroplatinate method.' These standards were of approximately the same particle size distribution as samples to be assayed. Specific background count caused by cosmic rays and other surrounding radiation was checked periodically by counting a sample of pure NaCl. Fig. 1 is a representative calibration plot. Assays were determined directly from the standard plot or calculated by subtracting the background count from the counting rate, then multiplying by the slope of the line. Chemical assays of the test samples were made by the Sherril method," a flame photometric technique, or the chloroplatinate method. Data: The radiation assay method has been used for three years by International Minerals & Chemical Corp. in the laboratory and in pilot plants processing ores containing potassium. These dry concentration plants process sylvinite and langbeinite ores at Carlsbad, N. M., and feldspar ores at Top-sham, Maine. Sylvinite ore is predominantly a mixture of syl-vite (impure KCl) and halite (impure NaCl). Contaminants include sulfates, such as langbeinite (2MgSO - K2SO4), kieserite (MgSO H2O), poly-halite (MgSO4.K2SO, 2CaSO, . 2H2O), and slimes. Langbeinite ore is predominantly langbeinite and halite with small amounts of sylvite, sulfates other than langbeinite, and slimes. Several variables, in addition to correct calibration and standardization of tubes, were found to be important in obtaining reproducible results. Particle size distribution of standard samples should be

Jan 1, 1959

Jan 1, 1922

By V. V. Strishkov, Zane E. Murphy, George Markon

Soviet industrial expansion depends on coal as a source of power and raw materials for the USSR's metallurgical and chemical industries. Knowledge of the Soviet Union's coal resources and production outlook is essential for a critical evaluation of the Soviet industrial potential. Although there is considerable literature on the Soviet coal industry, no single source provides an authoritative study of how the coal industry functions and how well it per- formed its job. Soviet reports are singularly lacking in the precise data in terms that are comprehensible to a westerner. It is essential, therefore, to clarify the terms in Soviet parlance. These terms are not comparable to those in common use in the West and are the cause of most inaccurate results. Official Soviet data on labor productivity refer to a limited group of "production workers" while in the West all wage earners are counted. Statistics are based on unprepared or run-of-mine coal, whereas it is customary elsewhere to measure productivity in terms of marketable coal. Thus, many western publications, while diligently and accurately reporting published Soviet data, overstate the case, presenting an exaggerated picture of Soviet progress in coal production and technology. (In terms of Western criteria, there is a three-fold exaggeration of labor productivity.)

Jan 5, 1973

By J. L. Weeks, K. F. Smith

IN order to determine the magnitude of thermal conductivity changes resulting from alloying vanadium with titanium and a few other elements, several sam~les were PrePared and measured. The thermal conductivity -values reported herein in Table I were determined with an apparatus previously described.' As in recently reported2 determinations on uranium and uranium alloys, whose thermal conductivities are in the same range as vanadium," the accuracy of the values was checked by using synthetic sapphire." The error in the measurement is estimated to be '-3 pct or 0.003 cal sec-1 cm-l "C-1, whichever is larger. The vanadium used in preparing the samples was the calcium-reduced type and was supplied by the Electro Metallurgical Co. as 99.6+ pct pure. All alloying elements used in the preparations were 99+ pct pure. A nonconsumable tungsten electrode arc furnace was used for melting the alloys and, without opening the furnace, each ingot was re-melted a number of times to insure homogeneity. The samples as prepared by the Armour Research Foundation were machined from as forged material without annealing. Acknowledgment The note is based on work performed under the auspices of the AEC. References 'J. L. Weeks and R. L. Seifert: Apparatus for the Measurement of the Thermal Conductivity of Solids. Review of Scientific Instruments (1953) 24, pp. 1054-1057. 2 J. L. Weeks: Thermal Conductivity of Uranium and Several Uranium Alloys. Trans. AIME (1955) 203, p. 192; Journal of Metals (January 1955). 3C. A. Hampel: Rare Metals Handbook. (1954) p. 593. New York. Reinhold Publishing Corp. Thermal conductivity of vanadium is given as 0.074 cal sec-1 cm- '°C-1 at 100°C. 4 J. L. Weeks and R. L. Seifert: Note Regarding the Thermal Conductivity of Synthetic Sapphire. Journal Amer. Ceramic Soc. (1952) 35, p. 15. At 70°C, K = 0.071 cal sec-l cm-l °C-1.

Jan 1, 1956

By C. E. Webber

The economical recovery of the valuable constituents from the effluent of gas-con-densate wells has developed into a problem of balancing the cost of recovery against the cost of compressing the residual gas back into the formation. A possible method of extracting the gasoline and distillate from the natural gas is by oil absorption at high pressures. In order to design and evaluate an absorption plant, fundamental data on the composition of the coexisting hydro- carbon vapor and liquid phases at various temperatures and pressures are essential. A review of the literature indicated that the necessary data for the design of such plants are lacking. The nearest approach to desired published data is that of Katz and Hackmuth,~ who experimentally deter-mined the composition of the coexisting vapor and liquid phases in a natural gas-crude oil system at pressures up to 3000 lb. per sq. in. and at temperatures from 40' to zoo°F. This paper presents the results of the experimental determination of the equilib-rium distribution of the hydrocarbons methane through hexane between natural gas and a typical absorber oil. The ranges of temperature and pressure chosen were from 33' to r8oUF. and from 100 to 5000 lb. per sq. inch. Materials The absorber oil was a typical naturally occurring, Straw-colored distillate that had previously been steam-distilled to an initial boiling point of 300 F. The physical and chemical properties, including the results of an Engler distillation, are presented in Table I. A large volume of this oil was obtained and it was used throughout the complete set of experiments. Table i.—Properties of the Absorption Oil Gravity .......................... . . 32.5' A.P.1. Molecular weight by benzene freezing- point depression.................. 183 Viscosity, poises; at 100°F........... 0.0a80 At 200°F...................... 0.0102 Composition, PeR Cent Aromatics........ 24.0 Naphthenes..... 36.7 unsaturates,Aromatics...... .I24.00.3 1 Parafins Naphthenes.....36.7 39.o EngLeR Distillation Per Cent /ncg. F. Per Cent Dez. P. Initial boilins rmint.. 300 I 60....... 523 5.................. 402 I 70....... 538 10.................. 421 180....... 557 20.................. 462 90....... 570 30.................. 480 1 95....... 623 40.................. 49 .................1 511 Residue, z .o per cent; loss, 0.3 per cent. See refrence I. The n-hexane was obtained from the Ohio Chemical and Manufacturing Co., Cleveland, Ohio. This liquid had a boiling range of from 149" to 152.6'F., with a density of 0.667 at 60°F. and a molecular weight of 85 by benzene freezing-point depression. The propane, isobutane, wbu-tane, isopentane and n-pentane were ob-ta,ined from the Philgas Department of the Phillips Petroleum Co. Certified analyses of these compounds showed their purity to be in excess of 99.5 per cent and they were riot further purified.

Jan 1, 1941

By C. E. Webber

The economical recovery of the valuable constituents from the effluent of gas-con-densate wells has developed into a problem of balancing the cost of recovery against the cost of compressing the residual gas back into the formation. A possible method of extracting the gasoline and distillate from the natural gas is by oil absorption at high pressures. In order to design and evaluate an absorption plant, fundamental data on the composition of the coexisting hydro- carbon vapor and liquid phases at various temperatures and pressures are essential. A review of the literature indicated that the necessary data for the design of such plants are lacking. The nearest approach to desired published data is that of Katz and Hackmuth,~ who experimentally deter-mined the composition of the coexisting vapor and liquid phases in a natural gas-crude oil system at pressures up to 3000 lb. per sq. in. and at temperatures from 40' to zoo°F. This paper presents the results of the experimental determination of the equilib-rium distribution of the hydrocarbons methane through hexane between natural gas and a typical absorber oil. The ranges of temperature and pressure chosen were from 33' to r8oUF. and from 100 to 5000 lb. per sq. inch. Materials The absorber oil was a typical naturally occurring, Straw-colored distillate that had previously been steam-distilled to an initial boiling point of 300 F. The physical and chemical properties, including the results of an Engler distillation, are presented in Table I. A large volume of this oil was obtained and it was used throughout the complete set of experiments. Table i.—Properties of the Absorption Oil Gravity .......................... . . 32.5' A.P.1. Molecular weight by benzene freezing- point depression.................. 183 Viscosity, poises; at 100°F........... 0.0a80 At 200°F...................... 0.0102 Composition, PeR Cent Aromatics........ 24.0 Naphthenes..... 36.7 unsaturates,Aromatics...... .I24.00.3 1 Parafins Naphthenes.....36.7 39.o EngLeR Distillation Per Cent /ncg. F. Per Cent Dez. P. Initial boilins rmint.. 300 I 60....... 523 5.................. 402 I 70....... 538 10.................. 421 180....... 557 20.................. 462 90....... 570 30.................. 480 1 95....... 623 40.................. 49 .................1 511 Residue, z .o per cent; loss, 0.3 per cent. See refrence I. The n-hexane was obtained from the Ohio Chemical and Manufacturing Co., Cleveland, Ohio. This liquid had a boiling range of from 149" to 152.6'F., with a density of 0.667 at 60°F. and a molecular weight of 85 by benzene freezing-point depression. The propane, isobutane, wbu-tane, isopentane and n-pentane were ob-ta,ined from the Philgas Department of the Phillips Petroleum Co. Certified analyses of these compounds showed their purity to be in excess of 99.5 per cent and they were riot further purified.

Jan 1, 1941

By R. S. Handy

DOES hand-sorting of mill feed pay? The fact that the practice is so general would seem to indicate that there must be good reasons for following it; yet, to my mind, the advantage in many cases is doubtful enough to invite a thorough discussion of the subject, in an effort to determine under what conditions hand-sorting does pay. A typical sorting plant in the Coeur d'Alene district handles about 800 tons of mine-run ore per day. The material is run over a grizzly with about 4-in. opening; the oversize is crushed to about 4-in. size and joins the undersize, and the whole product is washed and screened on trommels with about 1 ½ -in. openings. The oversize from these trommels is spread on a belt and the waste and first-class ore are sorted out by hand, the residue being further crushed, and passes, together with the trommel undersize, into the mill feed bins. About 50 tons of shipping ore and 150 tons of waste are sorted out per day, leaving about 600 tons of mill feed. To sort out this material requires 20 ore sorters and five bosses and repairmen. The normal cost of hand-sorting is about 16 c. per ton of run-of-mine ore, or 65 c. per ton of material sorted out. I believe that straight crushing and milling of the run-of-mine ore, in this case, is not only cheaper, but is metallurgically moree canonical and efficient than hand-sorting followed by milling of the residue. At one of the Bunker Hill rock-houses, 1250 tons of run-of-mine ore are reduced to pass 30-mm., or about 1 ¼ -in. opening in six hours, requiring five men. The equipment and the power consumed are not greatly different from that required in a sorting plant of the same capacity, and the normal cost of thus preparing the feed for milling is under 3 c. per ton of mine product. The relative cheapness of this method as against hand-sorting is thus clearly established, the saving being about 13 c. per ton. If there is any virtue in hand-sorting, then, it must lie in the metallurgical results achieved.

Jan 4, 1918

By Charles H. Morgan

Jan 1, 1905

Jan 1, 1904

By Otto C. Kopp, Thomas B. Crattie, Dennis R. Owen

Whole-rock analyses of limestones, fine-gralned dolostones and coarser-grained dolostones adjacent to mineralized breccias (Coy mine, Mascot-Jefferson City district) were compared with similar lithologies adjacent to apparently non-mineralized breccias at the new Thorn Hill section located approximately 39 km north of the Coy mine. Specimens were analyzed for Ca, Mg, Si, Al, K, Fe, Mn, Sr, Br, C1, S, Ti and P using X-ray fluorescence analysis. The concentrations of the major and most minor elements for Thorn Hill specimens fall within the range of concentrations for Coy mine specimens; however, significant differences (probability < 0.05) were noted for Fe, C1 and Br for fine-grained dolostones and for MgO, Fe and Mn for the coarser-grained dolostones. No significant differences were detected for the limestones.

Jan 1, 1985

By F. W. Lee

A GREAT CURTAILMENT of field activities among the geophysicists occurred last year, especially in prospecting for the common metals. In gold, however, an "outstanding achievement . . . was made by the engineers of Consolidated Goldfields. Here the suboutcrop of the Main Reef Series was traced from Middelvlei through properties of the westward area, a distance of from 30 to 40 miles. Here Drs. Reineche and Krahman prospected with the aid of a sensitive magnetometer and established the singularities of the various beds which heretofore had not been sufficiently appreciated. Several underlying shale beds were used to determine this suboutcrop under the dolomite. This area promises to be the equivalent of one-half the size of the present gold fields and to rank in value with the Far East Rand." The present temperature compensated magnetometers permit accurate field observations to less than 5 gammas. Since magnetic anomalies may have their origin due to a change of elevation as well as to the outcropping of a bed of another magnetically different material, intimate geological knowledge is of great assistance in the interpretation of these measurements. To what extent magnetic measurements reflect the basement when the material is homogeneous, consisting primarily of red granite, was determined by members of the Bureau of Mines and described by Dr. J. H. Swartz. Because of the diverse causes of magnetic anomalies, some of which were discussed and correlated by Stratton and Joyce upon known conditions, magnetometer measurements are often difficult to interpret.

Jan 1, 1933

Jan 1, 1911

By Joseph Pogue

THE, prices of crude petroleum and its derivatives have shown an upward trend from 1915 to 1920, and a downward trend from 1920 to 1923, see Table 1. Over the former period, oil prices were dominated by the rapidly increasing demands and inflation incident to the war and its aftermath, while over the latter period oil prices were influenced at the outset by deflation and then by the conditions of overproduction that have characterized the past three years. The purpose of this paper is to analyze the broader features of the more recent price movements in the petroleum industry and to relate these features to basic economic conditions in the industry. INDEX NUMBERS OF OIL PRICES The analysis and comparison of price movements may be facilitated by converting actual prices into relative prices, or index numbers, with 1913 taken as a base of 100. In this way, the various price groups are expressed as percentages of the 1913 prices and may thus be readily compared with one another or with the average prices of other commodities similarly expressed. Table 1 gives the index numbers representing the average prices of crude petroleum, gasoline, kerosene, fuel oil, lubricating oils, and all commodities. The last named is the index of all commodities as published by the U. S. Bureau of Labor Statistics and .is widely accepted .as the official measure of the general price level. The index numbers of oil prices were calculated by the writer from weekly quotations published in trade journals.

Jan 3, 1924

By Harry K. Ihrig

Jan 1, 1947

By Harry K. Ihrig

Jan 1, 1947

By Wayne C. Hazen, James K. Kindig

As the complexity of hydrometallurgical systems increases, it offers new opportunity for applications of solvent extraction. However, the high capital cost of mixer-settlers for large flow rates is a drawback to wide application in base metal recovery. This paper presents information on the use of cyclone separators in place of settlers with attendant significant reduction in capital cost. Various flowsheet possibilities for this development are discussed.

Jan 1, 1972

By H. S. Munroe

THE native copper of Lake Superior occurs in the form of fine grains and scales, disseminated in small percentage through the copper-bearing rock ; and in large and small masses, from a few pounds to several hundred tons in weight. Formerly the bulk of the copper came from the mines of Ontonagon and Keweenaw counties, producing mass copper. At present these mines furnish less than one-tenth of the total product, and fully one-half of this is from a single mine. The masses are usually found irregularly distributed in nearly vertical fissure veins, and require much dead work in sinking, drifting, and stoping for their development. The risk and expense attending the working of these mines have made them, with few exceptions, anything but profitable. * Read at the Montreal meeting, September, 1880.

Jan 1, 1880