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| Technology Projects > Deep Sea Mining > Activities |
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| Activities of the Group |
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1. |
To develop technology for polymetallic nodule mining from 6000m water depth. |
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To develop in-situ soil testing device for 6000m water depth. |
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Indigenous development of |
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Development of underwater vehicles for deep sea applications.
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Integration and Testing of ocean mining systems. |
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To develop data acquisition systems (DAS) for underwater systems. |
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Study and development of sub sea buoyancy systems. |
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| Details of Projects |
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1. |
Development of Underwater Mining System for long term operation: |
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As a first step towards development of Underwater Mining system for mining Manganese nodules at 6000m water depth, an Underwater Mining system operable at 500 meters water depth was developed. The Underwater Mining system is a crawler based system which moves on the sea-bed under remote control from the mother ship at top. The crawler has been designed to operate on the soft sea-bed and has special track belts with involute teeth to compact the bed during motion. Pumping operations was tested at 410m depth successfully. The Crawler was subsequently augmented for long term operation and successfully tested off Goa Coast at a depth of 451m. In the next phase the mining vehicle is being augmented with nodule collector and crusher system and its performance will be demonstrated at 500m. Based on its performance the system will be augmented for 6000m water depth for nodule mining. |
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Underwater crawler being launched |
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2. |
Development of Collector and Crusher system for manganese nodule mining: |
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NIOT had already developed an underwater mining machine for sand mining and successfully tested at a depth of 450m off the coast of Goa. In the second phase a crawler based mining machine with nodule collector, crusher and pumping system is being developed. The system in integrated form consists of nodule pickup and collecting device, sun sea crushing and pumping system with all the instrumentation and drive systems. The flexible riser concept is being used in this system. The entire structure is indigenously designed and fabricated at NIOT. The system is designed for mining rate of 8 tons/hour of wet nodules with nodule abundance of 5 to 10 kg/m2 in sea floor. The crushed nodules are pumped to the surface by a solid handling pump capable of delivering 45 m3 of slurry per hour. |
Side view of collector and Crusher System |
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Isometric view of Collector and Crusher system |
Integrated testing of Collector and Crusher system |
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Test setup for Collector-pickup system in Bendonite tank | |
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Before heading for actual sea trials, the Collector and Crusher system is tested for its performance in Bendonite tank, to simulate the real-time sea-bed soil properties. |
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Development of In-situ soil tester |
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In-situ soil strength values are very useful inputs for design of underwater crawler for mining nodules from soft sea floor. NIOT-Institute Konstruktion (IKS), University of Siegen, Germany team, jointly developed a soil tester capable of measuring soil properties in-situ which was tested successfully in 33m water depth. The tests were done in Ocean Research Vessel (ORV) Sagar Kanya. The soil tester measures the bearing strength of the soil using a cone tester and the shear strength by using a vane tester. An In-situ soil tester rated for 6000m water depth was developed jointly with Sevmorgeo, Russia. A new winch with drum and pedestal was realized to handle 7000m length umbilical cable. |
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In-situ soil tester (500m) |
In-situ soil tester (6000m) |
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Soil strength measurement at 5200m depth |
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Development of Underwater Thrusters |
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Underwater intervention systems like Remotely Operated Vehicle (ROV) and Remotely Operable Boat (ROB) are powered by underwater electric motor driven thrusters, which are imported currently. Keeping in mind the deep-sea activities in India, there is an immediate need to develop such thrusters in India and NIOT has embarked upon doing the same. An underwater thruster capable of operation at 1000m depth, delivering a power of 1kW, with 140mm diameter and 600mm length was developed in association with CMERI, Durgapur, PSG College of Technology, Coimbatore and IIT Madras. This was extensively tested to evaluate its performance and generates a bollard pull (forward) of 35kgf. |
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Underwater Thrusters |
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5. |
Development of remotely operable boat |
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NIOT uses highly sophisticated sub sea instruments. Quite often there is a need to test these Sub-sea systems which are used in deep sea mining vehicle before deployment. Remotely Operable Boat (ROB) can be used substantially for testing of such devices in lakes, backwaters etc. without the aid of support ship and avoiding high cost of chartering ships/ boats. Moreover ROB can also be used for near shore survey and mapping.
The design and fabrication of the Boat is warded to OED, IITM, Chennai as a project and the complete instrumentation, design of rudder assembly, integration and testing was done by NIOT.
Remotely Operable Boat (ROB) is an unmanned wireless remote operated autonomous catamaran. The boat is twin hull type and offers advantages like: wide deck area, high degree of stability against roll, strength and favorable resistance characteristics to waves. The boat is 6 meters in length, 3 meters in width and can cruise at 4 knots speed. An indigenously developed underwater electric thruster provides the propulsion power for the boat. The boat is operated from a light weight hand held operating panel either from a shore station or on board support ship.
ROB is an autonomous vehicle powered from (SMF) batteries kept distributed in two hulls. The boat can be operated continuously for 4 hours on full charge. ROB is operated within line of sight range and also carries a flashing marker lamp to indicate emergency conditions and location.
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Remotely Operable Boat |
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Development of Remotely Operable Artificial nodule laying system: |
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The Underwater mining system for Polymetallic nodule mining is being developed and qualified in different stages. The collector and crusher system developed was to be tested and qualified at 500m water depth. To qualify and evaluate the performance of nodule collecting, crushing and pumping system developed by NIOT, an artificial nodule bed is proposed to be created at 500m depth at the demonstration site. A remote controlled artificial nodule laying system was developed by NIOT.
Artificial Nodules closer with the properties of manganese nodules have been developed to create this type of sea-bed by laying them with the use Remotely Operable Artificial nodule laying system.
Artificial nodules were developed using clay mixed with saw dust as kernel and plain clay as shell. The nodules were cured in air for around 4 days and later fired in the kiln for 3 days. Various materials like fly ash and husk in various proportions were made as kernel to achieve the density, hardness and texture nearest to that of manganese nodule. It was observed that the combination of brick clay and sawdust in the kernel and brick clay in the shell after curing and firing was having density, hardness and aggregate impact test value closest as that of manganese nodules.
The artificial nodules were produced in various sizes in proportion with the distribution of manganese nodules in the Central Indian Ocean Basin i.e. size 25 to 30mm - 15%, 40 to 50mm - 40%, 60 to 70mm - 35%, greater than 70mm - 10% |
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| Remotely Operable Artificial nodule laying system | |
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Artificial nodules | Sectional view of artificial nodule |
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| 7.Collaborative Projects: Study of Hydraulic transport of large solids in hoses: |
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This is a joint venture development project executed with IIT Chennai to determine the pressure loss in the flow of large solids through hoses. This will benefit the selection of pumps for Deep-sea mining system for handling nodules.Pressure drop across bends can be studied for steady flows using FLUENT software and using conventional equations.
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Test setup for study of slurry flow |
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