Shallow - Water Sand - Mining Operation

Abstract

Abstract India is a registered pioneer investor under UN Convention on the law of the sea and has been allotted a mining site in the Central Indian Ocean for exploration and exploitation of manganese nodules, available at depths of 5000m to 6000m in Indian Ocean. To this effect, a joint collaborative programme between National Institute of Ocean Technology (NIOT), India and Institut f/r Konstruktion (IKS) of University of Siegen, Germany was initiated to develop a crawler based deep sea mining system with a flexible raiser. This programme is funded by the Department of Ocean Development, Government of India. Before embarking upon realising the total hardware for deep sea mining, it had become imperative to prove the above concept under shallow water condition at depths around 500m. The shallow water sand mining system consists of crawler, raiser and slurry pumping system, control & instrumentation and the related hydraulic system. The crawler is fitted with traction belts made of rubber, with a large bearing surface area to adequately meet the low bearing pressure of the soil. A manipulator mounted in front of the crawler holds the sand cutter or soil testing apparatus. The mined sand with water is pumped through a flexible hose onnecting the slurry pump and the mother ship. The slurry pump is a reciprocating pump. The entire drive system is obtained through hydraulic motors and actuators. There are two hydraulic systems to supply hydraulic fluid to the drive system and the actuators. The specially designed umbilical cable carries the required power and data to and from the crawler, also takes the load of the crawler and other subsystems. The control signals, transducer data and electrical power transmission are transmitted through this umbilical cable. The sand mining operation is a technology demonstration, envisaged to be deployed for deep-sea mining. The data from this testing would be made use of in validating the design of deep sea mining equipments at depths of 5000m to 6000m. The entire sand mining system costing about DM 5 Million is ready and the sand mining demonstration is expected by the end of 1998. Introduction: India, is a registered pioneer investor under the UN Convention on the law of the sea, and has been allotted a mining site in the central ocean for exploration and exploitation of manganese nodules. India, with a coast line exceeding seven thousand kilometers and with an exclusive economic zone of about two million square kilometers have been involved in the development of technology for deep sea applications since the last decade. India has an ambitious programme on deep sea bed mining for minerals, ocean energy in form of Ocean Thermal Energy Conversion (OTEC), wave energy programmes, and on Remotely Operated Vehicles (ROV) for general off shore surveillance amongst host of other offshore programmes. Though many countries have been showing keen interest to develop the deep-sea nodule mining technology, it has not yet been perfected to the stage of realising a economically viable commercial system despite the enormous efforts on the design and testing of sub-systems. This is mainly due to technological problems and large financial requirements. Hence, India is of the view that a joint development could be the best strategy to develop this technology.