TITLE:
Occurrence of Manganese Ore Deposits and Their Mineralogy in Vizianagaram-Visakhapatnam Manganese Ores Belt (Andhra Pradesh) India
AUTHORS:
Farhat Nasim Siddiquie, Juned Alam, Mohd Shaif
KEYWORDS:
Manganese Ore, Vizianagram, Andhra Pradesh, Dharwar Supergroup, Primary and Secondary Ores, Oxidation Zone, Ore Body, Open Cast Mine/Quarry
JOURNAL NAME:
International Journal of Geosciences,
Vol.6 No.6,
June
16,
2015
ABSTRACT: The Manganese deposits of
Andhra Pradesh are associated with a thick sequence of Precambrian rocks,
belonging to Khondalite and Charnockite groups of Dharwar Supergroup that forms
part of 2500 to 3000 m.y. old Eastern Ghat complex of India. The study area is
the Manganese deposits of Vizianagram-Visakhapatnam Manganese Belt of Andhra
Pradesh. The study area lies about 150 km NE of Visakhapatnam between 18°12′N -
18°30′N and 83°20′E - 83°45′E. The mineralization of Manganese ores is confined
to different rock types, belonging to both Khondalite and Charnockite groups,
where they are dispersed throughout the country rocks as small lenses, pockets,
veins and irregular bodies of varying dimensions. Quartz, garnet, clay,
limonite and apatite are the common gangue minerals in the Manganese ores. The
presence of quartz, garnet and apatite brings down the grade of the ore.
Ferruginous laterite and ochre generally work as capping of the Manganese deposits.
The various Manganese ore minerals present in these deposits are indentified as
1) Primary minerals-braunite, bixbyite, vredenburgite, jacobsite and
hausmannite, 2) secondary minerals-psilomelane, cryptomelane, hollandite,
pyrolusite and wad. The primary
ore minerals are considered to be syngenetic and regionally metamorphosed
while, the associated secondary ore minerals are formed due to alteration of
the primary ores.