CHENNAI: Oil and natural gas have been extracted from the seas for deca­­des, but ores and mineral deposits on the sea floor, which have the potential to change the face of economy, have still been elusive. But Indian scientists are making steady progress and an integrated mining system is under development for demonstration of deep-sea mining of polymetallic nodules (manganese nodules).

The Government of India has an area of 75,000 sq km in the Central Indian Ocean Basin (CIOB) for carrying out survey and exploration of these potato-shaped, largely porous nodules, found in abundance carpeting the sea floor. A rough estimate says that polymetallic nodules in the site allotted to India by International Seabed Authority (ISA) is about 380 Million Metric Tonne (MMT), with 0.55 MMT of Cobalt, 4.7 MMT of Nickel, 4.29 MMT of Copper and 92.59 MMT of Manganese.

Speaking to Express on the sidelines of a special thematic session on “Deep Ocean Research,’’ M Rajeevan, secretary, Ministry of Earth Sciences, said the Union government had signed a 15-year contract with ISA for exploration of polymetallic nodules, which expired this year. “Now, another five-year extension has been given for India to develop and demonstrate a workable deep-sea mining technology.

National Institute of Ocean Technology (NIOT) in Chennai has demonstrated the technology on a pilot scale and further research is going on at full pace,” he said.  Rajeevan added it was the biggest ocean engineering challenge, considering these nodules are to be mined from a depth of 6 km in an ultra high-pressure environment.

NIOT director Satheesh C Shenoy was confident that his team will crack the complex technology. Deep-sea Technologies and Ocean Mining Group of NIOT have already developed the crawler, which weighs 12 tonnes and a soil tester that will determine the characteristics of soil on the seabed where the crawler is deployed. “Currently, our team is developing the pumping system. Different components are being tested and will be integrated shortly. We hope to realise the full technology a couple of years down the line,” he said.

The idea is to have an integrated mining system where a crawler-based mining machine collects, crushes and pumps nodules to the mother ship using a positive displacement pump through a flexible riser system. It is expected that multiple mining machines will cover the mining field during large scale commercial mining operations. “The challenge is that the heavy crawler has to be lowered to a depth of 6 km using a conducting cable, which should transmit data as well as hold the crawler steady. Any mishap can sink the mother ship,” Shenoy said.

Rajeevan Nair clarified that India has permission to explore, but not commercially mine the minerals. “No country has the license to do deep-sea mining, but when the time comes, India should be ready to take advantage. India already has the technology to separate the minerals from dredged nodules. The Institute of Minerals and Materials Technology in Bhubaneswar has done lot of work on it.”

India’s Test Mine Site (TMS) is about 6,000 km away from Indian coast deep inside CIOB. Initially, National Institute of Oceanography (NIO), Goa had done close grid bathymetric (study of underwater depth of lake or ocean floors) surveys in 1.5 million sq km and identified manganese nodules deposits, of which 75,000 sq km was given to India for exploration and development of sustainable mining technology. NIOT director says what the scientists are developing may not be the final technology. “We can only develop an operational product, but it is for the industry to fine tune further to suit their bill,” he added.

Who regulates sea floor mining?
To regulate sea floor mining, in 1994 the United Nations Convention on the Law of the Sea spawned the International Seabed Authority, an independent treaty organisation. It has jurisdiction over seabed outside exclusive economic zones that surround nations’ shorelines
What are polymetallic nodules?
Manganese nodules are lumps of minerals ranging in size from a potato to a head of lettuce. They are composed mainly of manganese, iron, silicates and hydroxides. The greatest densities of nodules occur off the west coast of Mexico (in the Clarion-Clipperton Zone), in the Peru Basin, and the Indian Ocean

A rough estimate says that polymetallic nodules in the site allotted to India by International Seabed Authority (ISA) is about 380 Million Metric Tonne (MMT) with 0.55 MMT of Cobalt, 4.7 MMT of Nickel, 4.29 MMT of Copper and 92.59 MMT of Manganese

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