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Mohanty, J. K.
- FTIR Study of Lower Gondwana Coal from Talcher, Orissa
Authors
1 Regional Research Laboratory, Bhubaneswar - 751013, Orissa, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 51, No 3 (1998), Pagination: 371-376Abstract
Functional groups and mineral matters in Talcher coal have been identified with the help of FTIR. Oxygen bearing functional group mostly hydroxyl is common in bulk as well as different lithotypes. Minerals such as kaolinite, quartz, goethite etc. have been identified from the spectra. The functional groups data have been used to interpret the conditions of formation of the different lithotypes.Keywords
FTIR, Gondwana, Coal, Talcher, Orissa.- Chemistry of Chromites from Boula-Nausahi Igneous Complex, Keonjhar District, Orissa and its Petrogenetic Significance
Authors
1 Regional Research Laboratory, Bhubaneswar 751013, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 33, No 4 (1989), Pagination: 321-331Abstract
Chemical composition as well as different iomc ratios of chrome spinels of Beula-Nausahi ultramafic body, Orissa, have been determined. These data tell about the nature of original magma and temperature and oxygen fugacity of chromite crystallization. These data when compared with other well-known chromite deposits of the world, reveal a stratiform mode of origin for the deposit.- Chromite Alteration at Boula-Nausahi Igneous Complex, Orissa
Authors
1 Regional Research Laboratory, Bhubaneswar - 751 013, IN
2 Dept. Geology, Utkal University, Bhubaneswar, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 48, No 3 (1996), Pagination: 265-276Abstract
During Serpentinization of the ultramafic rocks, the accessory chrome spinels are altered at grain margins and/or along fractures to highly reflecting phases of ferritchromit and magnetite which occur as rims around parent chromite. Of these two altered phases, ferritchromit exhibits greater compositional variation. Electron probe microanalysis data indicate that these phases are rich in Fe and poor in Cr, Al and Mg with respect to parent chromite. Magnetite rim is characterised by extreme iron enrichment and marked depletion of Cr, Al and Mg whereas ferritchromit represents intermediate chemical composition between parent chromite and the magnetite outer rim. This compositional variation is due to solid state diffusion of elements from chromite outwards during serpentinization. Textural features, chemical composition and presence of chromiferous serpentine attest genetic relationship between serpentinization and chromite alteration.Keywords
Economic Geology, Chromite Alteration, Mineral Chemistry, Boula-Nausahi, Orissa.- Mineralogical and Chemical Characteristics of the Serpentinites from Boula-Nausahi Igneous Complex, Orissa
Authors
1 Regional Research Laboratory, Bhubaneswar - 751 013, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 48, No 2 (1996), Pagination: 161-170Abstract
The ultramafic rocks of Boula-Nausahi igneous complex have undergone extensive alteration resulting in the development of serpentinites. Petrographic and mineralogical observations have led to the recognition of two stages of mineral formation. The first stage (retrograde metamorphism) is characterised by complete transformntion of magmatic olivine to lizardite and the second stage (prograde metamorphism) in the formation of antigorite and alteration of accessory chrome spinels. Mineral assemblages indicate serpentinization to be a low temperature oxidation phenomenon. Formation of magnetite, ferritchromit and sulphide minerals is controHed by oxygen and sulphur fugacities prevalent during the process of serpentinization. Mineralogy, chemistry and geological setting of the serpentinites indicate an isochemical nature of the serpentinization process.Keywords
Economic Geology, Mineralogy, Serpentinites, Orissa.- Fe-Ti-Oxide Ore of the Mesoarchean Nuasahi Ultramafic-Mafic Complex, Orissa and its Utilization Potential
Authors
1 Institute of Minerals and Materials Technology, Bhubaneswar - 751013, IN
2 N/6-419, Jayadev Vihar, Nayapalli, Bhubaneswar - 15, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 72, No Spl Iss 5 (2008), Pagination: 623-633Abstract
The iron-titanium (Fe-Ti) oxide ore bodies occur as elongated bands within the gabbro-anorthosite suite of rocks of the Mesoarchean Nuasahi ultramafic-mafic complex. The ore consists mostly of titanomagnetite and ilmenite with minor amounts of hematite, spinel and ulvospinel. Goethite and martite are present as secondary minerals. The titanomagnetite grains display various intergrowth textures such as crystallographic intergrowth, granular intergrowth, graphic intergrowth, resulting from exsolution and oxidation above and below the magnetite-ulvospinel solvus.Bulk rock data shows that the ore contains 0.2 to 0.8 wt% V2O3 and 7.2 to 19.4 wt% TiO2. It is strikingly low in silica (0.4 to 2.8 wt%) indicating near absence of silicate minerals. The bulk rock chemistry in conjunction with mineralogical findings indicate that the ore minerals have undergone alteration resulting in development of martite, goethite and lepidocrocite. Ilmenite-magnetite geothermo-barometry data indicate that the mineralogical assemblage and textural characters have developed within a temperature range of 575 to 925°C and oxygen fugacity of 10-11 to 10-22.5.
The iron-titanium oxide ore bodies are genetically related to the gabbro-anorthosite suite of rocks. The present geometrical disposition of the ore bodies is due to residual liquid injection of the filter pressed - concentrated mass. The predominantly monomineralic nature of the ore body may be due to post cumulus sintering or annealing process. The utilization potential of these ores has been tested in producing a titania-rich slag (TiO2-88%) from which titanium can be recovered easily and for producing Fe-Ti-C composite (Ti-83%), a high value product.
Keywords
Magnetite, Ilmenite, Fe-Ti-C Composite, Ultramafic-Mafic Complex, Nuasahi, Orissa, India.- Distribution of Trace Elements in Coal-Lithotypes from Talcher Coalfield, Orissa
Authors
1 Regional Research Laboratory, Bhubaneswar - 75 1 013, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 68, No 4 (2006), Pagination: 675-684Abstract
Trace element distribution in bulk coal and lithotypes viz. durain, fusain, clarain and vitrain in two coal seams of two geological formations of Karharbari and Barakar from Talcher coalfield, Orissa is reported and compared with world coal trace element data. Karharbari coal (seam I) contains higher concentrations of As, Ba, Ce, Cr, Th, U and W than Barakar coal (seam II). On the contrary, coal from seam II has high concentrations of Be, Eu, Hf, Mo, Sb, Sc, Sm, and Zn. In both the formations, durain and clarain contain maximum trace elements including REE in appreciable concentration where as vitrain shows least trace constituents. Positive correlation of ash with Ba, Cs, La, Hf, Th, Rb and Sc indicates inorganic affinity of these trace elements. However Sb, As, Cr and Co show negative relation with ash explaining their organic affinilty.Keywords
Trace Elements in Coal, Barakar, Karharbari, Talcher Coalfield, Orissa.- Importance of Petrographic Study of Non-Coking Coals from Talcher Coal Field, Orissa in Coal Utilisation
Authors
1 Regional Research Laboratory, Bhubaneswar - 751 013, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 66, No 4 (2005), Pagination: 475-485Abstract
Talcher coal is non coking and high ash type and presently used for thermal power generation, sponge iron making, cement and chemical industry. Coal beneficiation is being carried out by size reduction followed by washing and gravity separation to reduce the ash content and improve other chemical parameters. Poor washability characteristics of Indian coals in general and Talcher coal in particular and presence of high near gravity materials do not support the conventional washing techniques resulting in below expected quality yield. The role of detailed petrographic studies during processing/benificiation needs special attention in order to improve the quality of coal and competitiveness of the product in the open market.This paper provides general information on petrogmphic findings of coal from different seams presently exposed in Talcher coalfield in terms of lithotype, maceral, mrcrolithotype, mineral matter and rank (vitrinite reflectance). Importance of lithotype, mineral matter and oxidation characteristics of coals with respect to coal preparation /beneficiation and maceral /microlithotypes in combustion has been discussed in detail.
Keywords
Petrography, Non Coking Coal, Utilisation, Talcher Coalfield, Orissa.- Sequential Leaching of Trace Elements in Coal: a Case Study from Talcher Coalfield, Orissa
Authors
1 Regional Research Laboratory, Bhubaneswar - 751 013, Orissa, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 58, No 5 (2001), Pagination: 441-447Abstract
The extent of vaporisation and subsequent condensation of many trace elements during coal combustion is largely dependent upon the mode of occurrence of the trace elements, besides many other parameters. Mode of occurrence of a few important trace elements in coals from Talcher coalfield representing low and high ash type from Karharbari and Barakar Formations is studied by sequential leaching experiments. It is observed that in both the coal samples, Cr and Mn exhibit more affinity towards organic matrix and/or insoluble oxide phases. Pb and Cd are mostly associated with soluble sulphide and oxide minerals. Co is mostly bonded with silicate phases in the coal samples. No definite mode of occurrence is visualised for Ni from the present study, as it is associated more with the residue indicating its association with either organic matrix or insoluble oxide.Keywords
Mode of Occurrence, Trace Elements, Leaching, Coal, Talcher Coalfield, Orissa.- Geochemistry and Petrogenesis of Pyrophyllite Deposit of Madrangjodi, Keonjhar District, Orissa
Authors
1 Department of Geology, Utkal University, Bhubaneswar - 751 004, IN
2 Institute of Minerals and Materials Technology, Bhubaneswar - 751 013, IN
3 Department of Geology, Ravenshaw University, Cuttack - 753 003, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 79, No 5 (2012), Pagination: 460-466Abstract
Pyrophyllite deposit at Madrangjodi is a large lensoidal massif overlain unconformably by Dhanjori quartzite and underlain by the parent Singhbhum granite (Phase - II). Pyrophyllite and quartz are the major minerals with minor to trace amounts of muscovite, chloritoid opaques and tourmaline. It is broadly divisible into lamellar, granular and schistose varieties. SiO2 (66.90-74.36 %) and Al2O3 (20.80-27.54 %) are the major oxides. The major elements data indicate its derivation from Singhbhum granite with depletion of SiO2 and increment of Al2O3. Trace and REE data are discussed to corroborate its genesis.Keywords
Pyrophyllite, Hydrothermal Alteration, Madrangjodi, Orissa.References
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