Journal of Geological Society of India (Online archive from Vol 1 to Vol 78)

B. K. Nayak ¹, Swati Mohanty ¹, Rajeev ¹, R. K. Sahoo ¹

Affiliations
1 Regional Research Laboratory, Bhubaneswar-751013, IN

Abstract

Normalised major and trace element data of manganese ores from Nishikhal are processed by using R-mode factor analysis of correlation matrix. Twenty major and trace elemental variables are expressed in terms of 3 common (rotated) factors to understand the mineralogical occurrences and the processes of formation of the manganese deposit. Varimax factor scores are used to classify in a finer detail the manganese ore types.

Keywords

Factor Analysis, Geochemistry, Manganese Ore, Orissa.

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B. K. Mohapatra ¹, P. P. Mishra ¹, P. P. Singh ², A. K. Paul ², Rajeev ¹

Affiliations
1 Regional Research Laboratory, Bhubaneswar, IN
2 Department of Geology, Utkal University, IN

Abstract

Co-Rich Lithiophonte is reported for the first time from low-grade Mn ores of the Bonai-Keonjhar belt (Jamda-Koira valley), Orissa. It occurs in two distinct Litho-Host associations, (i) lateritic zone capping Mn-ore horizon and (ii) shear zone-controlled siliceous manganese ore. It mostly appears as thinly banded and as Vug-Filled linings, in close association with cryptomelane. It occurs as Micron-Sized acicular to pea-shaped crystallites in the first litho association and as coarse, radiating crystals showing Zig-Saw pattern arrangement in the second association Co content is low (CoO 0 14 0 8%) in the Fine-Grained variety whereas in the Coarse-Grained variety it ranges up to 2% (CoO 0 14 2 00%). Appreciable quantity of Ni (N10 0 15-1 5%) is observed along with Co only in Coarse-Grained variety. The mechanism of Co-Entry into the two varieties of supergene lithiophorite through adsorption has been discussed Report of Co in terrestrial Mn-ore has opened up new potential in this part of Orissa.

Keywords

Lithiophorite (cobaltian), Manganese Ores, Bonai Keonjhar Belt, Orissa.

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