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By J. D. Mote, A. Rosen, J. E. Dorn

The effect of strain rate and temperature on the critical resolved shear stress for (1100) [1120] prismatic slip was determined for the intermediate hexagonal phase containing about 67 at. pct Ag and 33 at. pct Al. Whereas the flow stress increased only slightly as the test temperature was first decreased below room temperature, a rapid increase inflow stress was obtained with yet greater decreases in temperature from about 240" to 4°K. The effect of both temperature and strain rate on the flow stress over the low-temperature range could be completely rationalized in terms of the Peierls mechanism when the deformation is controlled by the rate of nucleation of pairs of kinks. A few years ago Mote, Tanaka, and Dorn1 observed that the critical resolved shear stress for prismatic slip of a 67 at. pct Ag plus 33 at. pct A1 hexagonal intermediate phase by the (1100)[1120] mode decreased precipitously as the test temperature was increased from 4" to about 160°K. Their results for both basal and prismatic slip are given in Fig. 1. It is obvious that only the flow stress for prismatic slip is strongly temperature-dependent, whereas the flow stress for basal slip is independent of temperature. If the temperature dependence of the flow stress were primarily due to interstitial impurities, it might be expected that they would influence the flow stress for basal slip as well. Since the activation volume at 115°K for prismatic slip was determined to be about 15b3, where b is the Burgers' vector, this thermally activated deformation process was tentatively ascribed as being due to the Peierls mechanism. But the various analyses of the Peierls mechanism then available as formulated by Seeger2 and also by Lothe and Hirth3 did not agree well with the experimental data. Since that time a more realistic theory for the operation of the Peierls mechanism under conditions where the strain rate is determined by the rate of nucleation of pairs of kinks has been presented by Dorn and Rajnak.4 The present investigation was, therefore, undertaken in order to provide the essential data for a careful check on the agreement between this theory and the low-temperature deformation by prismatid slip of the above-mentioned Ag2A1 intermediate phase. EXPERIMENTAL TECHNIQUE Single-crystal specimens so oriented that the [1120] direction and the normal to the (1100) plane were at 45 * 2 deg to the tensile axis were grown from the congruent melting composition of about Ag2Al for the intermediate hexagonal phase by the

Jan 1, 1964

By D. Mohapatra

Extraction of Al(III) from aqueous sulfuric acid solutions into organic Cyanex 272®-carbon tetrachloride systems was investigated from a multi-component mixture containing aluminum, cobalt and nickel. Al(III) extraction efficiency was quantitative with 1.0 M Cyanex 272® in two stages at an aqueous: organic (A:O) phase ratio of 1:1 and an equilibrium pH of 3.2. The stripping of Al(III) from the loaded organic (LO) with different acids indicated sulfuric acid to be the best stripping agent. More than 99% stripping of Al(III) from the LO was achieved using 2 M H2SO4 at an A:O phase ratio of 1:1 in a single stage. The stoichiometry of the extracted species of Al(III) was determined by the slope analysis method. The extraction reaction proceeded via the cation exchange mechanism and the extracted species was assumed to be AlA3?3HA, where HA refers to the dimeric and A the anionic form of the extractant, Cyanex 272®. The extraction of Al(III) was studied in the presence of various ions to ascertain the tolerance limit of individual ions.

Jan 1, 2008

By Martin J. Kenwright

Within the famous Harrods department store, a new lift shaft has been constructed, servicing a depth of 22m below ground level as well as the existing 6 storeys of the store. The shaft will connect with a new goods tunnel which is to be excavated beneath the shop, as well as new floor space above ground level which has resulted from the infilling of a previously existing lightwell within the store. The construction of the deep shaft while maintaining uninterrupted use of the store by the Client led to a number of innovative solutions being undertaken. Empirical assessments were made of settlements anticipated from the construction process, which took place within a congested environment of existing foundations. Various elements were designed and installed to mitigate the effects of the inevitable ground movement on the surrounding overlying structure, which supported sensitive high quality finishes and mechanical and electrical installations The reinforced concrete lining of the shaft was contained within a cofferdam of minipiles. The minipile placement accuracy (1 in 150) was vital as it could not interfere with the subsequent tunnelling works. As the scheme progressed this became even more critical since the minipiles were needed as support for parts of the permanent works This paper describes:- the high quality placement and control of the minipiled cofferdam, the methods employed in assessing ground movements and the techniques used to mitigate against the effects of these movements.

Jan 1, 2000

By Thomas J. Keefe, O&apos

The effects of cobalt, B-naphthol, glue and antimony on the polarization behavior of zinc sulfate electrolyte were investigated. It was found that B-naphthol was beneficial in reducing the detrimental effects of cobalt while antimony and excess glue were each harmful. Since the nu cl eat ion over potential was insensiti1ve to coba1t, other regions of the polarization curve were used to indicate electrolyte balance. The low? current density area occurring in the reverse or anodic sweep direction was? often an indicator when an ?unstable condition existed. The two parameters evaluated were the degree of inflection in the polarization curve in the low current density region during scanning and the rate of current rise observed when the sample was potentiostated at -0.781 Volts (SHE). Using this technique, a two-additive system was shown to be desirable to control cobalt and antimony containing electrolytes. The structure of the deposits was examined using scanning electron microscope techniques.

Jan 1, 1985

By Ralph P. Carter

It is apparent that coal will play an increasingly important role in satisfying the nation's energy requirements for the remainder of this century. Both deep mining and surface mining will be practiced to develop known U.S. coal reserves, but until significant improvements in the productivity of deep mining emerge, surface mining is likely to be predominant. This report addresses the problems of coal extraction and surface mine reclamation in the 11-state Midwestern coal resource region, where surface stripping of high-sulfur, bituminous coal has been a well-developed industry for most of this century. Midwestern coal markets have declined in recent years. In part this is a result of widespread conversions to more convenient and (apparently) economical liquid and gaseous fuels, but the decline in Midwestern coal use is also attributable to the impact of current air pollution control regulations that prohibit emissions of sulfur oxides and particulate matter. A part of the regional demand for Midwestern coal has been transferred to the Northern Great Plains where extensive low-sulfur coal reserves are currently being developed.

Jan 1, 1974

By P. Tong-jiang

We studied mineralogical characteristics of the vermiculite samples from seven mines in China. We found three types of interstratified structures in the investigated samples: 1:1 regular interstratified structure, segregated interstratified structure, and random interstratified structure. The vermiculite samples from six mines are mainly composed of phlogopite?vermiculite interstratified minerals, and the samples from the other mine are composed of chlorite?vermiculite interstratified mineral. The samples with phlogopite?vermiculite structure have high contents of K2O, TiO2 and Na2O. The samples with chlorite?vermiculite structure have the highest contents of MgO and Al2O3. The cation exchange capacity of the samples is 17.3?99.0 mmol/100g.The exchangeable cations of phlogopite?vermiculite samples from Weili Mine mainly include Na+ and Ca2+, while those of phlogopite?vermiculite samples from Tongguan Mine mainly include Mg2+ and Ca2+. The thermal expansion ratio of the samples is between 9 and 32. The exfoliated vermiculite products from Weili Mine have the best mechanical strength.

Feb 27, 2013

By José Luis Calderón, Percy Arrosquipa

Compañía Minera Poderosa ha identificado una interesante oportunidad de generar valor y de mejorar tanto el clima laboral como el de relaciones comunitarias mediante el proyecto descrito en este artículo. El proyecto se orientó a motivar la incorporación de prácticas de responsabilidad social, tanto entre proveedores de bienes y servicios, como entre empresarios mineros artesanales en proceso de formalización. Como ejemplo, se analiza el caso del cofinanciamiento de la obra “Mejoramiento del sistema de agua para consumo humano del anexo Pueblo Nuevo”, que benefició a 195 familias con un servicio de agua de calidad las 24 horas del día. De este modo, se corrigió una fuente de conflictos sociales y se materializó una alianza para el desarrollo local entre la mediana minería y la minería artesanal. Por su parte, Asociación Pataz entregó certificados de donación, deducibles del Impuesto a la Renta, a los aportantes.

Sep 30, 2017

By A. T. Tye

WHEN the roughing tables operated in 1923 were abandoned, all the coarse iron pyrite for-merly removed by the tables had to be ground to flotation size, which caused an increased power con-sumption of 2 kw.-hr. per ton. Recently, by increasing the tonnage, this has been reduced to a total of 16.6 kw.-hr. per ton. The cost of repairs has been slightly reduced by using an alkaline circuit instead of the acid mine water used in 1923. Other economies from elim-inating roughing tables and the finishing tables have more than compensated for the extra grinding and the total costs have remained practically the same, until the first part of 1927, when, with increased tonnage, the total cost has decreased to 72 cents and the repair cost to 9 cents. In 1923, with a combined gravity and bulk flotation flowsheet, the grade of concentrate was only 4.38 per cent copper. With preferential flotation this has in-creased to over 17 per cent copper. The tailing has decreased from 0.29 per cent -copper to 0.18 per cent. The copper recovery, instead of decreasing; as might be expected, has increased from 87.4 per cent to, 91.5 per cent. The silver recovery has also increased from 88

Jan 8, 1927

By Ronald F. Ayers

The study upon which this paper is based was completed by Battelle's Columbus Laboratories for the U.S. Army Corps of Engineers in 1974. It is but part of an overall effort by the Corps to evaluate the costs and benefits to the nation of waterway improvements. This study is primarily concerned with future coal markets for production from those counties near the Wabash River in the heart of the Eastern Interior Province. An objective here is to consider a most pessimistic energy (and hence, coal) demand for planning purposes.

Jan 1, 1976

By R. E. Radabaugh, J. M. Brown, J. S. Merchant

The Gilman district is on the northeast flank of the Sawatch Range in central Colorado. It has yielded a total of 10,000,000 tons of ore having a value of over $250,000,000. Paleozoic sediments intruded by a Tertiary quartz latite sill and unconformably overlying Precambrian intrusives and metasediments comprise the country rock of the area. The sediments strike northwesterly and dip 8° to 12° northeasterly. Structures in the Precambrian are related to the Homestake shear zone of the Colorado mineral belt. Only minor folding and faulting occur in the sediments. The principal ore bodies are massive sulfide replacement deposits in carbonate rocks. They consist of long, pipe-like mantos in the completely dolomitized Mississippian Leadville Limestone and funnel-shaped chimneys of copper- silver ore cutting across the Mississippian and Devonian strata. Mineralization is continuous from the chimneys into the mantos. The principal ore bodies are roughly in the shape of a four-tined fork which points up dip. Smaller manto deposits occur in the Cambrian Sawatch Quartzite, and fissure veins are present in the Precambrian rocks. The principal minerals in the mantos are marmatite and galena in a gangue of pyrite and manganosiderite. The chimneys consist of a central core of pyrite with erratically distributed chalcopyrite, tetrahedrite, freibergite, and occasional galena with a shell of zinc ore on the outer margin. Both the chimneys and the mantos are surrounded by imperfect shells of manganosiderite and sanded dolomite. The mineralization is of Laramide age. Hydrothermal alteration affects all rock units to varying degrees. Clay mineral alteration halos occur around the ore bodies. Hydrothermal solutions have developed sanded rock, rubble filled channels, and banded zebra textures, principally in the Leadville Limestone. Structural control of the ore bodies is not well defined. Both the location of the district and the chimneys are probably related to basement structures. The mantos are largely controlled by stratigraphic factors and a pre-Pennsylvanian karst topography in the Leadville Limestone, which were modified by hydrothermal activity, and by weak zones of northeasterly trending faults.

Jan 1, 1968

By Arnulf Muan

PHASE relations in three isothermal sections (l000°, 1100°, 1200°C) of the system Ag-Fe-Pd have been determined as part of a program to develop improved crucible materials for containing low-melting iron silicates at low oxygen potentials. The following experimental method was used: Two- to 3- g samples of each of forty different alloys within the system Ag-Fe-Pd were made up from metals of 99.9 pct purity. The mixed metal powders were contained in a 1-cc crucible of dense recrystal-lized alumina and heated in a protective atmosphere (90 vol pct A, 10 vol pct H2), first to complete melting for approximately 30 min and subsequently at the desired equilibration temperature (1000°, 1100°, or 1200°C) for approximately 24 hr. The samples were then quenched rapidly to room temperature and examined metallographically as well as by X-ray techniques. Unit cell dimensions were compared with standards obtained by study of one-phase alloys of known compositions. The results are summarized in diagrams (a), (b), and (c) shown in Fig. 1. Heavy solid curves outline areas comprising compositions of mixtures consisting of the phases labeled for each area. Mixtures in which liquid is the only condensed phase present are confined to very narrow areas adjacent to the Ag-Pd join at high silver contents. An enlarged, distorted picture of the phase relations prevailing in these areas is shown in the upper-left circular insert. Particular attention is directed toward the misci-bility gap which occupies major parts of the composi-

Jan 1, 1962

By W. E. Hess

AT the Vesta mines of Jones & Laughlin Steel Corp. on the Monongahela River, 35 miles south of Pittsburgh, JCM Joy continuous miners and 6-SC shuttle cars are used for pillar extraction in the Pittsburgh seam. The entire output of the mine goes into coke production for blast furnace operation. Because this coal, which has high metallurgical qualities, is close to the place where it is ultimately used and because supplies with these properties are being rapidly depleted, complete recovery is essential wherever possible. With the introduction of the continuous miner into the Vesta mines, therefore, it was necessary to plan a project which would facilitate development and provide for future total recovery. Use of continuous miners under varying conditions has necessitated changes with regard to roof action, method of development, method of pillar attack, and innovations in mining. In the following pages these changes will be discussed. Prior to the introduction of continuous miners the Pittsburgh seam at the Vesta mines averaged 72 in. of mineable coal, overlain with 12 to 16 in. of draw-slate, which weathers on exposure to air and is not firm enough to be held in place. Immediately overlying the drawslate is a wild or rooster coal, very irregular in thickness, varying from 12 to 30 in. Above the rooster coal the strata consists predominately of shales or lime shales and sandstone. Just before the introduction of continuous miners in the Vesta mines, however, a definite change took place in the character of the roof structure overlying the coal seam, see Fig. 1. Thickness of laminated roof immediately overlying the rooster coal varies with localities and introduces a problem in roof control. In fact, a set of eight main entries being developed in Vesta NO. 4 mine entered an area with so difficult a roof structure that management considered abandoning the section altogether. In this locality the roof consisted of thin alternate layers of roof coals and shales, with an occasional irregular seam of slick slate, the whole being laced with slips, and the coal itself being cut by clay veins and spars. In an effort to overcome some of the difficulties, roof bolting was introduced in 1949. This made it possible to recover coal from an area which otherwise would have been economically unmineable. There have been very few roof bolt failures. When conventional machines were replaced by continuous miners there were changes in the development of butt entries. By these changes it was hoped: 1—to speed development, 2—to provide as much solid coal as possible for the machine on retreat, 3—to avoid the necessity of crossing entries already driven, 4—to facilitate ventilation, 5—to provide a roadway for shuttle car haulage which would eliminate the necessity of running through doors or curtains, 6—to provide better roof control by increasing the distance between the center lines of entries, and 7—to provide more coal when the machine was in position to load.

Jan 1, 1956

By W. Bassow

In June 1972, when the United Nations convened its historic Conference on the Human Environment, only 24 countries had established government agencies with environmental responsibilities. Of these, 11 were in the industrialized world, 13 in the Third World. By 1985, the number had dramatically surged to a world-wide total of 145, with the greatest growth among the developing countries to 110, an increase of almost 1000%.

Jan 1, 1988

By Gautam Chandra Mondal

An attempt has been made to carry out qualitative assessment of mine water discharges from the different mines of West Bokaro Coalfields of Hazaribag district of Jharkhand, India. A total of 33 mine water samples were analyzed for pH, electrical conductivity (EC), major cations (Ca, Mg, Na, K), major anions (HCO3, SO4, Cl, NO3), and heavy metals (Fe, Mn, Cu, Zn, Pb, Cr, Ni, Co, As). The hydrochemical data has been evaluated in terms of major ion chemistry, solute acquisition processes and suitability of mine water for domestic, industrial and irrigation uses. The pH of the analyzed mine waters varies from 5.27?8.43 indicating acidic to alkaline nature of the water. The electrical conductivity (EC) values varied from 276 µScm-1 to 1598 µScm-1 for measured samples and spatial differences between the EC values reflects the wide variation in lithology, surface activities and hydrological regime prevailing in the region. The anion chemistry of the analyzed water samples shows the dominance of SO4 and HCO3 with a minor contribution from Cl, NO3 and F. The observed high values of sulphate in the mine water of the area may be attributed to the oxidative weathering of pyrites. On average chloride is contributing 5% of the total anionic balance (TZ-). Fluoride and nitrate have low concentrations and on average contributing <2% the total anions. The cation chemistry indicates that 79% of the samples are Ca>Mg>Na>K, while the 6% belong to Ca>Na>Mg>K and 1% of Ca>Mg>K>Na. Weathering of rock forming minerals and cation exchange processes normally control the levels of these cations. Concentrations of some heavy metals (Fe, Mn, Ni, Cr) are found to be well above the prescribed permissible levels recommended for the drinking water. The water quality assessment for drinking purposes indicates that most of the mine water having high TDS, total hardness (TH) and sulphate concentrations. This suggests that mine water of the study area is not suitable for direct use in drinking and domestic purposes and needs a proper treatment before its utilization. The assessment of water for irrigation uses show that the water is good to permissible quality and can be used for irrigation uses. However, high values of salinity, %Na, SAR, RSC and Mg-hazard at certain sites restrict its suitability for agriculture uses. Keywords: mine water; ion chemistry; quality assessment; West Bokaro coalfields

Sep 1, 2012

By Scott W. Hazen

In recent years many mining companies have recognized that their chance for continued economic survival depends on the adaptation of technological advances in their operations. Increased productivity through new developments in mining methods and improvements in equipment has made mining and processing of lower grade ores possible. Cost analysis has produced accurate data on the costs for development, production, and processing of ore. All of these changes and cost studies have shown the necessity for increased accuracy in determining the grade of ore. Methods of estimating grade in a mineral deposit have not kept pace with the technological advances in the other areas. The same methods are in use today as in the past. Experience and judgment are major criteria of accuracy and the results are highly subjective. In 1953, as part of its research program to develop a better understanding of fundamentals of mining technology, the Federal Bureau of Mines began a sampling method research project at its Denver Mining Research Center. The basic objective of the project is to investigate sampling methods and to study the adaptation of the techniques of statistical analysis to mine sampling.

Jan 1, 1961

By Gorzalczynski. Stan

The recent trend in underground mine developments is ?big is better?. This is most certainly evident in the mine shaft and the conveyances that operate within its compartments. Today, there are several new installations requiring mine cages that can transport up to 170 passengers. The technology in mine hoisting is advancing to address a combination of higher capacity requirements, deeper hoisting depths and faster winding rates, however, some areas of the hoist plant have not changed for the past fifty years. The most notable of these areas is the shaft compartment guide string and the conveyance mounted safety arrest mechanism. The technology in use today for the protection of passengers in a shaft conveyance from a hoist rope severance incident, remains conceptually unchanged from Elisha Otis? design of 1850. The actual retardation components, the safety dogs, have taken on several forms since Elisha?s invention with the last major design change occurring in the late 1940?s. The arrest of a free falling shaft conveyance requires that the shaft guides withstand the energy imparted on them by the safety dogs. There are some very real limitations presented by the use of wood for this application. The new hoisting era will most certainly continue to demand larger capacity equipment but also, an increased awareness toward safety.

May 1, 2002

By Frederick W. Breaks, Andrew G. Tindle, Julie B. Selway

"Abstract - Rare-element pegmatites may host several economic commodities, such as tantalum (Taoxide minerals), tin (cassiterite), lithium (ceramic-grade spodumene and petalite), and cesium (pollucite). Key geological features that are common to pegmatites in the Superior province of Ontario and Manitoba, Canada, and in other large tantalum deposits worldwide, can be used in exploration.An exploration project for rare-element pegmatites should begin with an examination of a regional geology map. Rare-element pegmatites occur along large regional-scale faults in greenschist and amphibolite facies metamorphic terranes. They are typically hosted by mafic metavolcanic or metasedimentary rocks, and are located near peraluminous granite plutons (A/CNK > 1.0). Once a peraluminous granite pluton has been identified, then the next step is to determine if the pluton is barren or fertile. Fertile granites have elevated rare element contents, Mg/Li ratio < 10, and Nb/Ta ratio < 8. They commonly contain blocky K-feldspar and green muscovite. Key fractionation indicators can be plotted on a map of the fertile granite pluton to determine the fractionation direction: presence of tourmaline, beryl, and ferrocolumbite; Mn content in garnet; Rb content in bulk K-feldspar; and Mg/Li and Nb/Ta ratios in bulk granite samples. Pegmatite dikes with the most economic potential for Li-Cs-Ta deposits occur the greatest distance (up to 10 km) from the parent granite.Metasomatized host rocks are an indication of a nearby rare-element pegmatite. Metasomatic aureoles can be identified by their geochemistry: elevated Li, Rb, Cs, B, and F contents; and by their mineralogy: presence of tourmaline, (Rb, Cs)-enriched biotite, holmquistite, muscovite, and rarely garnet.Once a pegmatite dike has been located, the next step is to assess its potential to contain Ta mineralization. Pegmatites with the highest degree of fractionation (and thus the most economic potential for Li-Cs-Ta) contain blocky K-feldspar with >3,000 ppm Rb, K/Rb < 30, and >100 ppm Cs; and coarsegrained green muscovite with >2,000 ppm Li, >10,000 ppm Rb, >500 ppm Cs, and >65 ppm Ta. Pegmatites with Ta mineralization usually contain Li-rich minerals (e.g., spodumene, petalite, lepidolite, elbaite, amblygonite, and lithiophilite) and may contain Cs-rich minerals (e.g., pollucite, Cs-rich beryl). The ore minerals of Ta are commonly manganotantalite, manganocolumbite, wodginite, and microlite; Ta-rich cassiterite is also commonly present. Tantalum mineralization tends to occur in albitic aplite, mica-rich (lepidolite, cleavelandite ± lepidolite), and spodumene/petalite pegmatite zones."

Jan 1, 2005

By Greenleaf W. Pickard

The Parral mining district is located in the southern part of the state of Chihuahua in north-central Mexico, in the border area of the physiographic provinces of the Mesa Central and the Sierra Madre Occidental, at an average elevation of 1700 meters. This is one of the most highly productive lead-zinc districts of Mexico. The principal operating units are the Prieta, Santa Barbara and San Francisco mines. The Santa Barbara-San Francisco del Oro area is located 25 kilometers to the southwest of the Prieta mine. It has a system of generally narrow veins in fault zones, entirely in the shale series. The Santa Barbara veins follow long, persistent fractures, while the San Francisco del Oro veins are in relatively short fractures. The Veta Colorada structure, located 5 kilometers to the northwest of the Prieta mine, was a major producer of high grade silver ore with low lead-zinc content during the eary 1900&apos;s. It follows a major north-south fault zone in andesite and is noteworthy for a number of wide oreshoots of limited vertical extension along its 10 kilometer length. The Palmilla and Esmeralda mines are on the south end of the Veta Colorada structure. Numerous smaller mines are operating in the Parral area. During the last 45 years the Prieta mine has produced approximately 15,000,000 tons of complex sulfide ore, principally from one single vein. Extensive stoping has

Jan 1, 1970

By D P. Sainsbury, J Western, B L. Sainsbury, V Mutton, P E. Petrie

Remnant rib pillars at Castlemaine Goldfields Ltd’s Ballarat Gold Project have been sterilised by the placement of loose rock fill in production stopes. The application of selectively injecting low-viscosity grout into the backfilled stopes to form a stabilised material has enabled recovery of the previously sterilised pillars. This paper outlines the engineering design, quality control and quality assurance program implemented to ensure the safe and efficient recovery of the rib pillars. The successful program included laboratory testing, numerical exposure stability modelling and in situ monitoring.CITATION:Sainsbury, B L, Sainsbury, D P, Western, J, Petrie, P E and Mutton, V, 2014. Pillar recovery adjacent to stabilised rock fill at the Ballarat Gold Project, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 77–86 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By J. E. Gebhardt

External control of the electrochemical potential of a bed of mineral particles has been investigated by the Bureau of Mines as a method for controlling particle inter-action with organic collectors and thus, flotation response. A cylindrically shaped, 200-to 300-g bed of sulfide mineral particles was used as the working electrode to examine the potential distribution in the bed. The dissolved oxygen concentration of the electrolyte had a significant effect on the potential profile across the mineral bed. Low oxygen levels were necessary to achieve uniform electrochemical potential distributions. Flotation separation of a chalcocite-pyrite mineral mixture by controlled potential was achieved using ethylxanthate, but the flotation behavior of chalcocite and pyrite from the mixture does not follow the flotation behavior of the individual minerals. That is, the presence of another sulfide mineral alters the flotation behavior with ethylxan-thate. Galvanic interaction due to mineral-to-mineral contact between chalcocite and pyrite contributes to differences in the recovery. Chalcocite dissolution products had a deleterious effect on pyrite flotation by activating flotation below -0.1 V (saturated calomel electrode) and depressing flotation above -0.1 V. Pyrite dissolution products had no effect on chalcocite flotation.

Jan 1, 1985