Geotechnical properties of the Plio-Pleistocene Sediments from nodule bearing area in the Central Indian Basin have been studied to know shear strength and water content variation with depth. To reveals that surface sediments have low (<1kPa) shear strength which increases with depth. Average undrained shear strength of siliceous sediments -is 3.6kPa and average water content is 430%. Bioturbated layers show increase in water content and reduction in shear strength. Calcareous core collected from nodule barren area indicates low water content (20] %) and wide scatter in shear strength (3-14kPa).
Polymetallic nodules are widely spread on deep seafloor of the world oceans at 4 to 6km water depths. These nodules are considered as a future strategic metal resource due to their enrichment in copper, nickel cobalt and manganese (Yamazaki, et al. 1990). The Central Indian Rasin (CTR) in the Indian Ocean has been known for its economic potential of polymetallic nodules after the National Institute Oceanography, Goa completed preliminary but expensive exploratory survey of this basin in 1987. The major achievement of this survey was allotment of the Pioneer Area by UNCLOS (United Nations Convention on Law of the Sea) to the Government of India in 1987 and exclusive rights for further development of these mineral resources. Various geological aspects of nodules and sediments of this basin are studied by scientists at Geological Oceanography Division of NIO, Goa. However not much attention was given towards the geotechnical studies of nodules and associated sediments which are mandatory for mining as well as for environmental impact studies. To have suitable mining design, work on geotechnical studies of the sediments associated with the nodules has been started (Khaoge,1992). Though several countries have been developing deep-sea mining technology, a problem of suitable and commercial miner still remains unsolved.
