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By S. C. Termes

The Bureau of Mines has used Fourier transform infrared spectroscopy (FT-1R) to study in situ reactions of aqueous solutions of potassium ethylxanthate with CU(II)-and Pb(II)-activated sphalerite plates, in which the plates were both the infrared-transparent windows and the reacting surfaces. A copper (I) ethylxanthate formed predominantly with Cu(II)-activated sphalerite, regardless of the activation time. The products formed on Pb(II)-activated sphalerite depended on the activation times; a short activation time (30 min) yielded a lead ethylxanthate-like product, but a long activation time (90 min) yielded a considerable amount of dixanthogen.

Jan 1, 1986

By A. L. Engel

Production of chromite in California has been from many small, high-grade mines. The opening of the Purchase Depot at Grants Pass, Oreg., in 1951 has stimulated chromite mining in California, and a large number of properties are being reexamined as there is a possibility that some low-grade ores from many of these properties can be beneficiated to meet the purchasing schedule. The Bureau of Mines in its program of conservation is continuing ore-dressing tests on chromite ores to better evaluate their potential. This report is a compilation of preliminary concentration tests on samples from five different properties in California. The concentration tests were made on ores from the David mine, Butte County, the Seiad Creek mine, Siskiyou County, the High Plateau mine, Del Norte County, Bud's mine, Tuolumne County, and tailings from the Miller concentration plant in San Luis Obispo County, Calif., to determine the possibility of beneficiating these ores so that they will meet the specifications for the Government stockpile.

Jan 1, 1956

By Francisco Macías

"El drenaje ácido de mina AMD (Acid Mine Drainage) es la principal causa de contaminación de aguas en la Faja Pirítica Ibérica. En ese sentido, el presente texto señala una forma de tratamiento de drenaje de dicha faja a través del pretratamiento natural para oxidar y retirar fierro, así como del tratamiento pasivo DAS, denominado DAS-calizo, el cual se centra en la retención de metales trivalentes y el paso del sistema, llamado DAS-magnésico enfocado en la descontaminación de Zn, Mn, Cd, Co y Ni. PO. La aplicación del proyecto se realizará por LIFE-ETAD, -en tanto posibilita la viabilidad de un sistema pasivo para la descontaminación metálica en este tipo de aguas ácidas."

Jul 1, 2016

By Thomas Fraser

About 24 per cent of our total production of bituminous coal is used in industrial power plants. As regards fuel conservation, therefore, the recovery of unburned fuel from furnace refuse presents interesting possibilities. Considerable attention has been given to this problem in the past, but because of the comparatively low initial cost of power plant fuel in the pre-war period little progress, has been made in this direction in the United States. Because of the higher price of coal in Europe more attention has there been given to the problem. In Germany a process has been developed for separating unburned coal in refuse by using an electromagnetic separator In the United States the use of mechanical stokers enabled low-priced screenings of high ash content to be used, so that even with relatively high percentages of combustible material remaining in the refuse, the loss in money is not excessive. If the price of screenings returns to the pre-war level around $1.00 per ton the process proposed here will probably not be especially interesting, except where the freight charges are very high. However, if the price of delivered coal continues high, such a process should result in considerable saving. The cost of continuous operation of such a refuse treating plant should not exceed 75 cents per ton of fuel recovered.

Jan 1, 1921

By G. L. Oldright, Virgil Miller

"This paper is the ninth 4 of a series on smelting in the lead blast furnace, and the fourth on modifications brought about by the introduction of richer charges.ACKNOWLEDGMENTSThe authors wish to express their appreciation to Stanley A. Easton, Frank M. Smith, and A. F. Beasley, and to their staff for the whole—hearted cooperation that made it possible to obtain the data in this publication at the Bunker Hill smelter, Kellogg, Idaho.INTRODUCTIONIn tie account written of the conditions obtaining at the tuyere zone in the blast furnaces at Tooele (R. I. 2965) the authors gave references to articles covering (1) the effect of temperature on the equilibrium 2C0 - CO2 + C, (2) experimental work that has been done on learning the gases existing at various elevations in columns of burning coke, (3) extension of this work to the tuyere zone of an iron blast furnace, and (4) the paper itself gave similar analyses of the gaseous oxides of carbon at the tuyere zone of a lead blast furnace and showed the temperatures obtaining there. There were also references in the above paper to the literature on (5) how the lead compounds likely to be present might be ex¬pected to react. A careful study of the original articles selected as references will give a good background for the present work.The following very brief recapitulation may be convenient before considering the tuyere zone in the blast furnaces at Kellogg. The ""producer gas reaction"" (1) of course goes to the left at increasingly higher rates of speed with increase of temperature. When air is blown upward through a grate and a column of hot fine coke alone, oxygen as such penetrates from some 2 to 3 inches only, under the conditions obtaining as to the amount of surface exposed per unit volume of air. When air is blown at about 20 pounds pressure through the tuyeres in the side of an iron blast furnace into a column of coarse coke (plus furnace charge) it may penetrate for 30 inches before the oxygen is entirely used, burning first largely to CO2. Within wide limits, the rate of feeding air into the furnace has practically little effect on the composition of the gases obtaining in the fuel bed of fine coke, this being true particularly of the gases leaving the bed. Some 10.5 inches above the grate the gases contained 22 per cent of CO by volume, and a little further up the CO2 had practically disappeared. This gave the familiar three zones in both the iron blast furnace and the gas producer; in order of entry of the air, in the first the oxygen burned largely to CO2, in the second the CO2 was reduced to CO, and the third the CO2 was practically absent. In the furnaces at Tooele, conditions were somewhat erratic but the first two zones were present, there being, however, no zone in which CO2 and 02 were both entirely absent."

Apr 1, 1931

By GORDON H. FISHER

During the year 1945, the drilling pace in West Texas increased above that in the year 1944, and represented the highest number of well completions since 2941. The 1680 new wells drilled 8,287,958 ft. of hole for a per well average of 4933 ft. This depth is approximately 30o. ft. deeper than the average for the year 1944. Although the deepest well drilled in West Texas (Phillips Petroleum Company's Ada Price No. 1, in Pecos County) was completed during the year. 1944 to a depth of 15,279 ft. and tested the Ellen-burger horizon, the producing depth record for West Texas was set during the year 1945 with the completion of Amerada Petroleum Corporation's Jones No. I-A, in the Jones Ranch field, Gaines County, which now is producing at 11,422 ft. from the Devonian formation.

Jan 1, 1946

By Xiaoyan Luo, Congcong Dai, Gaipin Cai, Xin Liu, Lu Zong

To overcome the difficulty of accurately judging the load state of a wet ball mill during the grinding process, a method of mill load identification based on the singular value entropy of the modified ensemble empirical mode decomposition (MEEMD) and a probabilistic neural network (PNN) classifier is proposed. First, the MEEMD algorithm is used to decompose the vibration signals recorded under different load states to obtain the intrinsic mode components, and a correlation coefficient threshold is used to select the sensitive mode components that characterize the state of the original signal. Second, singular value decomposition is used to obtain the singular value entropy. Finally, the load state of the wet ball mill is judged based on the magnitude of the singular value entropy. A characteristic mill load vector is constructed from the singular value entropies of the cylinder vibration signals recorded under different load conditions and is used as the input to a PNN, which then outputs the predicted ball mill load state; in this way, a load state identification model is established. Grinding experiments are presented to verify the effectiveness of the proposed method, showing that the method can accurately identify the load state of a wet ball mill. ()

Francis Drake, Bulawayo, Rhodesia, So. Africa (communication to the Secretary *):—I should like to place on record some data in addition to those given by Mr. Canby in his paper. I regret that my notes have been destroyed so that I can give no accurate measurements of the water jacket that I am about to describe. This furnace mas erected in Cerro Gordo, Inyo county, Cal., early in 1875, and I think it quite possible that it was the first applied in lead smelting. It was made of plate iron and elliptic in shape, the inner dimensions being about 54 by 42 in. by 48 in. high. The distance between the inner and outer plates was about 6 in. Tuyere holes, one at the back and two on each side, about 12 in. in diameter, were made in this, and in these were placed cast-iron water tuyeres about 16 in. long, the diameter of the blast orifice at the point being about 3 in. The height from tuyeres to feed door was about 9 ft., but the top of the charge was kept about 5 ft. above the tuyeres. There was a space of about 12 in. between the jacket and the top brick-work. This brick-work was supported by a cast-iron plate resting on four cast-iron columns. At the beginning, the jacket was lined with air-dried radial bricks, made of crushed quartz and fire-clay, as it was thought that the jacket would not stand the heat on its bare plates. After a short time the practice was altered and no lining mas put in. The jacket was closed at the top and had a steam drum connected by two pipes at the back. This steam drum was connected to the boiler in which the steam was made for driving the Baker blower, the rock breaker and the pumps. The bottom of the jacket mas also connected to the boiler. The jacket was run under boiler pressure (80 Ib.) for some time, but eventually cracks developed in the inner plate between the tuyere holes,

Jan 1, 1913

By E. E. White

I DISAGREE with Mr. Brinsmade on several points, and I will discuss his remarks under the same six topics which he has used. 1. Rate of Interest Earned by Sinking-Fund.-I believe Mr. Brinsmade is confused in his ideas as to the effect of new gold on the interest earned on money. The flood of gold which he mentions certainly should not operate, to increase interest rates, but since it replaces and adds to liquid capital should reduce interest rates and counteract the destruction of liquid capital which he mentions. Furthermore, it is doubtful if the destruction of capital since 1897 by wars and catastrophes has been any greater in proportion than in similar periods before 1897. With regard to savings banks, I would say that only 3 per cent. is allowed on deposits through a large part of the West. As to bonds, they can be bought to yield any rate. of interest desired up to 6 per cent., but, a 5 per. cent. bond is not as safe as a 4 per cent. bond, nor a 4 per cent. bond as safe as a 3 per cent. government security. I do not understand why Mr. Brinsmade says that Mr. Denny's quoted opinion of a 3 per cent. rate is evidently based on English conditions before the Boer War. Certainly there is no reference to the Boer war or to English conditions in Mr. Denny's article. M. Howard Burnham, in his admirable work on mine valuation, says': ". For instance, redemption is taken at 3 per cent., because even 4 per cent. represents a greater risk, as is indicated by the purchase of Government paper to bear only 3 per cent., the great desideratum of the .latter being security." . Again, Mr. Burnham says:2 "The tables are calculated on the assumption that the dividends shall accumulate at 3 per cent. only, as in accordance with the general idea set out elsewhere, a rate greater than 3 per cent. involves appreciable risk with which it were inaccurate to saddle the sinking-fund if risks are to be segregated, this being the basis of all the writer's calculations."

Jan 6, 1914

By John P. Hager, Adolfo R. Zambrano

The thermodynamics properties of the liquid Pb-Ag-Au system have been determined from galvanic cell measurments five pseudobinary systems of fixed XAg/XAu ratio. The galvanic cell employed a molten PbO-SiO2 electrolyte and was operated between 775" and 1030°C. The thermodynamics properties of lead were obtained directly from the experimental data, whereas the excess integral molar properties and the activities of silver and gold were obtained by means of the Gibbs-Duhem equation. The calculated proper -ties of the Ag-Au system agree well with the published properties. The liquidus surface of the Pb-Ag-Au system has been determined at 1200°K. In Parts I' and 11' the galvanic cell Mo,Pb(l)|(PbO-SiO2)(l) SiO2(s) |Pb(alloy)(l), Mo [I] was used to determine the thermodynamics properties of the Pb-Ag and Pb-Au systems, respectively. The use of cell I, in which a molten oxide electrolyte is employed rather than the classical fused-salt electrolyte, was shown to result in more accurate ther-modynamic measurements in that the displacement reaction at the alloy-electrolyte interface (l/Zb)B(alloy) + (I/za)A+Za = (1/Za)A(alloy) + (1/Zb)B+zb [1] was minimized. For the Pb-Ag system, where B = Ag(l), the error in the activity of lead (aPd) re-sulting from Reaction [I] was calculated to be less than 1 pct.l For the Pb-Au system the error in aPb was calculated to be less than 0.5 pct.2 Also, electro-transport measurements on the PbO-SiO2 electro-lyte1,2 established that the conduction was entirely ionic and that lead was present only in the divalent state. In the present study the experimental technique is extended to an investigation of the thermodynamic properties of the liquid Pb-Ag-Au system. Five pseudobinary systems of fixed X Ag/XAu ratio were selected. The experimental results were then combined with the previous measurements on the component binary systems Pb-Ag1 and Pb-AU2 to calculate, by means of the Gibbs-Duhem equation, the molar and partial molar mixing properties for the liquid ternary solutions.

Jan 1, 1970

The Kinross DeLamar Mine has been operated for more than 17 years producing precious metals dore' from ores, principally silver bearing with associated gold co-products. In late 1995 a new orebody was commissioned, the Stone Cabin orebody, and the site began a phased shift from silver dominance to gold dominance in terms of precious metals revenue. The Knelson Concentrator was selected to remove gold from a portion of the cyclone underflow stream in the grinding circuit. This paper describes the development of the flow sheet, specific mineralogical impacts on Knelson product and downstream materials, and impacts on mine/mill grade reconciliation.

Jan 1, 1997

By Jerome P. Downey

The Indium Corporation of America - Colorado School of Mines Indium Separation Technology was evaluated as a potential means of treating smelter flue dusts stockpiled at the Pintlar Corporation property in Kellogg, Idaho. The patented technology represents a method for segregating the contained indium, lead, and other metals in forms acceptable for downstream processing and recovery. Separation is effected by treating the dust with metallic sodium in a bath of molten lead. Process effectiveness was measured by determining the relative distribution of key metals between the bullion and dross products at small pilot plant scale. The study indicated that application of the technology to the Pitlar samples results in a highly efficient concentration of lead in the bullion, while indium is collected in the dross. The distribution of other key metals between the bullion and dross products and the effect of varying selected process parameters are also discussed.

Jan 1, 1994

By Zhang. L.

Ordered intermetallic PtSb had been synthesized by arc-melted and then sintering treatment. The electro-oxidation of formic acid on PtSb was investigated at room temperature by cyclic voltammetry and chronoamperometry. The results are compared to those at a polycrystalline platinum electrode surface. It was found that PtSb intermetallic was catalytically more active than pure platinum according to the onset potential and current density. XRD and XPS technologies had been used to investigate the crystal structure and electron effect. We think formic acid decomposition on PtSb favors the reactive intermediate route and is not very much affected by the CO intermediate as compared to Pt.

Jan 1, 2005

Prof. J. W. Richards, South Bethlehem, Pa. (in reply to several questions):—The cut representing some of the round briquettes which were under test shows that, at the brcaking-stresses, they break into lumps, and do not disintegrate into powder. The process is simplicity itself. I have followed the different processes for sintering iron-ores and flue-dust, am interested in all of them and wish them all success; but this process appealed to me strongly by its simplicity. It is in line with a method which I once tried to work out myself, but which never came to anything, namely, the agglomeration of fine iron-ores by means of Portland cement. As small an amount as 5 or 6 per cent. of Portland cement will enable fine ore to agglomerate and set into a briquette, but when I came to estimate the cost, I found it was a little too high. The Schumacher process, curiously enough, does not work well on iron-ore, but flue-dust thus treated does harden and give a strong briquette. In my attempts to find a reason for this difference, it has occurred to me that possibly the particles of flue-dust had been coated over with some sublimed silica, which might be an agent in the setting. But I found by experiment that neither sublimed silica, nor ordinary silica, nor ordinary alumina, would briquette. Chemically pure iron oxide briquetted quite hard; but the application of pressure is a necessary part of the operation. If simply moistened with the solution and allowed to stand it does not set hard, but the more pressure applied to it the hardcr it sets. Evidently the flue-dust particles must be pressed very close together in order to get the small proportion of active material wet, so that the particles shall act at their points of contact; for it is evident that only at the points of contact does the cementing action take place. The reactions are facilitated by considerable pressure, bringing the acting particles close together, and may go on with

Jan 1, 1913

By W. D. Hausel

The Wyoming craton in the western United States is a favorable terrane for diamond deposits. The craton hosts a variety of ultramafic, ultrabasic, and ultrapotassic rocks. Additionally, a few hundred 'kimberlitic' heavy mineral anomalies and some geophysical and remote sensing anomalies indicate the presence of undiscovered, mantle-derived, pipes in the craton. The Wyoming craton is separated into a Wyoming 'archon' known as the Wyoming Province, and the Colorado 'proton' known as the Colorado Province. The 'archon' underlies much of Montana and Wyoming and continues north into Alberta and Saskatchewan; the Colorado 'proton' underlies much of Colorado and a small portion of Wyoming. Although most exploration geologists would consider the 'archon' the most favorable terrane for commercial diamond deposits, the 'proton' has produced more than 120,000 diamonds, while the 'archon' has not been very productive.

Jan 1, 1996

By S. Castro

Molybdenite flotation is strongly depressed at pH higher than 9.5 in the flotation of Cu-Mo ores in sea water. Chemically sea water contains mainly Na+ and Cl- ions, but also some secondary ions, such as SO42-, Mg2+; Ca2+, HCO3-; etc., which are not necessarily indifferent for the flotation of molybdenite. The natural floatability of molybdenite in sea water and in NaCl solutions containing different secondary ions is investigated by micro-flotation tests. The tests indicate that the floatability of molybdenite in alkaline media in 0.6 M NaCl solutions is not affected by the presence of anions, such as, SO42- and HCO3-, at concentrations similar to those occurring in sea water. However, a strong depression of molybdenite at pH ranging from 9.5-10.0, is produced by the alkaline earth metal cations (Ca2+ and Mg2+ ions), dissolved in distilled water or in 0.6M NaCl solutions. It was found that effect of Mg2+ions is significantly stronger than Ca2+ ions. Effect of both ions is attributed to hydrolysis and adsorption of MOH+ hydroxy-complexes. This is followed by subsequent precipitation of hydrophilic colloidal hydroxides at the molybdenite/solution interface, and in bulk solution.

Sep 1, 2012

By Joseph Goodwill

1. PURPOSE The objective of this paper is to summarize a study undertaken by the EPRI Center for Metals Production (CMP). The overall purpose of the study was to identify electrolytic opportunities that might merit consideration for joint development by industry and EPRI. 2. SCOPE The electrolytic technologies of interest to this study include: Electrorefining, Electrowinning, and Fused-salt electrolysis. Recovery from primary, secondary, and waste materials were included in this effort; however, we excluded from consideration: Plating and coating operations, such as electrogalvanizing; Mining and milling operations in which electric energy is predominantly used for comminution; Electrothermal processes in which submerged-arc, open electric-arc, and plasma-based smelting processes use electric energy largely to provide a melting or refining ("heating") capability; and Aluminum electrotechnologies since these were the subject of a separate study (CMP 86-2). We recognize that there may be some "gray areas" between these excluded areas and the electrolytic sectors of interest. For this reason, a secondary criterium was used, namely, if the major use of electric energy was to extract or refine the

Jan 1, 1990

Jan 1, 1980

By Arístides Sotomayor

El presente texto señala el comportamiento del mercado nacional de cobre en el período 2000- 2013, donde se analiza la evolución de la producción minera metalúrgica a través de la identificación de las tendencias anuales en el mercado peruano.

Jan 1, 2015

By Michael G. Zabetakis

Investigation of gas explosions usually reveals that the combustible gases have come from transmission and storage facilities or from natural gas or oil wells. However, combustible gases such as methane and hydrogen can derive from biological processes. Hazardous situations have been created in the past by the use of abandoned mines for the disposal of sewage and rainwater, by the interconnection of storm and sanitary sewers, by sealing the openings in manhole covers when repaving the roadway over a sanitary sewer, and by the construction of buildings over or near garbage fill areas without adequately providing for the release of combustible gases.

Jan 1, 1962