Fifteen beach sand samples were collected from a depth of 1mt at different locations of the Astaranga beach, Puri with an interval of 300 mts. The beach sand samples were studied for heavy mineral concentration at dif...Fifteen beach sand samples were collected from a depth of 1mt at different locations of the Astaranga beach, Puri with an interval of 300 mts. The beach sand samples were studied for heavy mineral concentration at different location points and were subjected to scanning electron microscope studies for the mineral ilmenite. The percentage of total heavy mineral in Astaranga beach varies from 16.42% to 24.47%. The important minerals are ilmenite, rutile, zircon, sillimanite, garnet, monazite, pyroxene and others. For all samples a set of sieves bearing ASTM nos. 30, 40, 60, 80, 100, 120, 140, 170 and 200 corresponding to 0.59 mm, 0.42 mm, 0.25 mm, 0.177 mm, 0.149 mm, 0.125 mm, 0.105 mm, 0.088 mm and 0.074 mm respectively were used to separate different size fractions. The sieve mesh sizes vary from 0.59 mm to 0.74 mm. It was observed that maximum concentration of heavies was confined to +200 ASTM sieve or 0.74 mm. The total average heavy mineral concentration and light mineral concentration was found to be 20.07% and 79.49% respectively. The concentration percentage of different heavy minerals varied from higher to lower in the order like ilmenite, zircon, sillimanite, garnet, rutile, pyroxene, monazite and others. The ilmenite mineral in this area is found to have altered to secondary phases like pseudorutile, leucoxene and rutile along the fractures, cavities and grain boundaries. The alteration condition was observed as streaks, irregular patches, bands, and rim like structures around the ilmenite grains. Detailed study of alteration in ilmenite was carried out by Energy Dispersive Spectrometer (EDS) attached to Scanning Electron Microscope. The potentialities of heavies found at different locations of the Astaranga beach suggested a good source for the exploration. The alteration of the mineral ilmenite and high concentration of heavy minerals clearly pointed to the sedimentary environment and mechanical concentration process due to repeated wave action.展开更多
The Ib-valley coalfield of Odisha, India contains five coal seams viz. Ib-seam at the bottom overlain successively by Rampur seam, Lajkura seam, Parkhani seam and Belpahar seam. Twenty one representative samples were ...The Ib-valley coalfield of Odisha, India contains five coal seams viz. Ib-seam at the bottom overlain successively by Rampur seam, Lajkura seam, Parkhani seam and Belpahar seam. Twenty one representative samples were collected from three major seams (Ib, Rampur and Lajkura) and their petrography and chemical studies were carried out. Samples were not collected from the Parkhani and Belpahar seams as these are very small seams exposed locally having no regional correlation. The macroscopic study shows the dominance of durain which imparts a dull appearance to these coals. The maceral analysis reveals that vitrinite percentage varies from 4.5% to 80.2%, the exinite from 3.30% to 22.2% and the inertinite from 12.5% to 92.2% in different samples of the Ib valley coalfield. The very high proportion of inertinite suggests a shallower water deposition of plant materials followed by prolonged period of exposure and repeated cycle of weathering. The proximate analysis results show that the top Lajkura seam is comparatively lower in rank than the underlying Ib and the Rampur seam. The ultimate analysis exhibites that the percentage of variation in C is found from 77.88 to 85.79, H from 4, 4 to 5.91 and O from 7.26 to 15.3. H/C and O/C ratio including C.V. in this coalfield showing distinct variations from the bottom to top seam. The analyses results indicate that the petrographic and chemical characters of the ib valley coals are stratigraphically controlled.展开更多
文摘Fifteen beach sand samples were collected from a depth of 1mt at different locations of the Astaranga beach, Puri with an interval of 300 mts. The beach sand samples were studied for heavy mineral concentration at different location points and were subjected to scanning electron microscope studies for the mineral ilmenite. The percentage of total heavy mineral in Astaranga beach varies from 16.42% to 24.47%. The important minerals are ilmenite, rutile, zircon, sillimanite, garnet, monazite, pyroxene and others. For all samples a set of sieves bearing ASTM nos. 30, 40, 60, 80, 100, 120, 140, 170 and 200 corresponding to 0.59 mm, 0.42 mm, 0.25 mm, 0.177 mm, 0.149 mm, 0.125 mm, 0.105 mm, 0.088 mm and 0.074 mm respectively were used to separate different size fractions. The sieve mesh sizes vary from 0.59 mm to 0.74 mm. It was observed that maximum concentration of heavies was confined to +200 ASTM sieve or 0.74 mm. The total average heavy mineral concentration and light mineral concentration was found to be 20.07% and 79.49% respectively. The concentration percentage of different heavy minerals varied from higher to lower in the order like ilmenite, zircon, sillimanite, garnet, rutile, pyroxene, monazite and others. The ilmenite mineral in this area is found to have altered to secondary phases like pseudorutile, leucoxene and rutile along the fractures, cavities and grain boundaries. The alteration condition was observed as streaks, irregular patches, bands, and rim like structures around the ilmenite grains. Detailed study of alteration in ilmenite was carried out by Energy Dispersive Spectrometer (EDS) attached to Scanning Electron Microscope. The potentialities of heavies found at different locations of the Astaranga beach suggested a good source for the exploration. The alteration of the mineral ilmenite and high concentration of heavy minerals clearly pointed to the sedimentary environment and mechanical concentration process due to repeated wave action.
文摘The Ib-valley coalfield of Odisha, India contains five coal seams viz. Ib-seam at the bottom overlain successively by Rampur seam, Lajkura seam, Parkhani seam and Belpahar seam. Twenty one representative samples were collected from three major seams (Ib, Rampur and Lajkura) and their petrography and chemical studies were carried out. Samples were not collected from the Parkhani and Belpahar seams as these are very small seams exposed locally having no regional correlation. The macroscopic study shows the dominance of durain which imparts a dull appearance to these coals. The maceral analysis reveals that vitrinite percentage varies from 4.5% to 80.2%, the exinite from 3.30% to 22.2% and the inertinite from 12.5% to 92.2% in different samples of the Ib valley coalfield. The very high proportion of inertinite suggests a shallower water deposition of plant materials followed by prolonged period of exposure and repeated cycle of weathering. The proximate analysis results show that the top Lajkura seam is comparatively lower in rank than the underlying Ib and the Rampur seam. The ultimate analysis exhibites that the percentage of variation in C is found from 77.88 to 85.79, H from 4, 4 to 5.91 and O from 7.26 to 15.3. H/C and O/C ratio including C.V. in this coalfield showing distinct variations from the bottom to top seam. The analyses results indicate that the petrographic and chemical characters of the ib valley coals are stratigraphically controlled.
