NISCAIR Online Periodicals Repository Collection: JSIR Vol.65(01) [January 2006]

Comparison of different extraction methods to determine gold in geological samples

Thu, 29 Dec 2005 22:58:59 GMT

Title: Comparison of different extraction methods to determine gold in geological samples

Authors: Raju, P V Sunder

Abstract: Different petro-chemically varied lithological samples were collected from the Chitradurga schist belt, Karnataka, to identify auriferous zones. The efficiencies of gold estimation at very low levels by different extraction methods were compared. The extraction methods were fire-assay (FA), cyanide leach, and methyl isobutyl ketone (MIBK) solvent extraction. The rock samples include banded iron formations (silicate, oxides, carbonate and sulphide facies), ferruginous cherts, massive milky white quartz veins and highly sheared fractured translucent dark grey to bluish grey quartz veins. After separation and pre-concentration of gold, MIBK solvent extraction procedures have been studied using flame atomic absorption spectrophotometer (F-AAS).

Page(s): 65-67

Effect of co-solutes on the physico-chemical properties of surfactant solutions

Thu, 29 Dec 2005 22:58:59 GMT

Title: Effect of co-solutes on the physico-chemical properties of surfactant solutions

Authors: Sansanwal, P K

Abstract: Physico-chemical studies of some aqueous surfactant solutions were carried out by employing conductance, surface tension and spectrofluorometric techniques. From conductivity and surface tension measurements, critical micelle concentration (CMC), counter-ion association (α), equivalent conductance at infinite dilution (٨₀), surface excess concentration (), minimum area per molecule (A_min), surface pressure at CMC ( _CMC), thermodynamic properties of micellization (Gº_mic, Hº_mic, Sº_mic) and adsorption (Gº_ads, Hº_ads and Sº_ads) have been obtained for an anionic [bis (2-ethylhexyl) sulphosuccinate sodium salt (AOT)], a cationic [cetyl trimethyl ammonium bromide (CTAB)] and a nonionic [polyethylene (23) lauryl ether (Brij-35)] surfactant solutions. Effect of mixing co-solutes (dioxane and glycerol) on the physico-chemical properties of surfactant systems at 298.15, 308.15 and 318.15 K has been investigated. Surfactants micellar characteristics and their interaction with co-solutes were also investigated by fluorescence measurements of solutions using pyrene as a fluorescence probe.

Page(s): 57-64

Slope stability study for optimum design of an opencast project

Thu, 29 Dec 2005 22:58:59 GMT

Title: Slope stability study for optimum design of an opencast project

Authors: Singh, V K

Abstract: The stability of an opencast mine slope, investigated by the limit equilibrium method, indicates that 148m deep open pit is stable with 60° overall slope angle. Geotechnical mapping was undertaken to determine the critical orientation of structural discontinuities. Geomechanical properties were determined in the laboratory and subsequently modified to approximate those of in situ rock mass. Sensitivity analysis was done to determine the influence of the slope design parameters on the safety factor. It was also used in determining the most suitable remedial measure for the critical slope. Slope monitoring did not reveal any movement in and around the pit.

Page(s): 47-56

Microprocessor based flow meter for measuring flow rate of cryogenic liquids

Thu, 29 Dec 2005 22:58:59 GMT

Title: Microprocessor based flow meter for measuring flow rate of cryogenic liquids

Authors: Ray, S K; Bandopadhyay, L K; Singh, R P; Sahay, N; Ahmad, I; Narayan, A; Bhowmick, B C

Abstract: This paper presents the design of a microprocessor-based flow meter to optimize the flow rate of liquid nitrogen required to control fire in underground coalmines. The salient features of the device and its set-up procedure with the liquid nitrogen tanker are illustrated with suitable schematic diagram. The program logic of the proposed device is illustrated in the form of a flow chart.

Page(s): 42-46