The first attempt to mine manganese nodules in a deep water environment was successfully accomplished during the summer of 1970 in the Atlantic Ocean. The conclusion of this prototype test established a significant milestone in man';s attempt to commercially mine natural resources from the ocean floor.
During the thirty day operation on the Blake Plateau, significant tonnages of nodules were pumped through 9 5/8 inch O.D. pipe in 2,500 feet of water. Pipe strain, air-lift pumping data, and ship motion were monitored and recorded by engineer and technicians throughout the operation.
The primary purpose of this paper is to describe some of the operational techniques and equipment used on the which was converted from a type cargo ship. Nearly all of the shipboard equipment was originally developed for the marine or oil industry. - Major components which are described in the paper include:
ship
dredge pipe
pipe handling equipment
pumping system and
instrumentation.
The information gathered from the prototype dredging test confirmed that new technology combined with conventional equipment can be used to permit the commercial hydraulic dredging of deep ocean ore deposits.
"....the final success of underwater mineral exploitation lies in imaginative, thorough development of conventional engineering techniques rather than in new and highly sophisticated devices." That statement, made by John E. Flipse in his paper in 1969, reference I, expresses the basic philosophy which was followedin the design and construction of the first deep ocean prototype mining vessel - R/V DEEPSEA MINER.
This vessel was used to recover manganese nodules in 2,500 feet of water on the Blake Plateau. Although the nodules in this area lacked sufficient assay value to be mined and processed commercially, the general area provided an excellent proving ground for testing recovery techniques. The remainder of this paper will describe the marine and oil field techniques which contributed to the successful completion of the prototype test.
The prototype mining system utilized a pipe suspended from a ship in 2,500 feet of water. The nodules were entrained in seawater and pumped to the surface through the dredge pipe. A separator on the ship separated the nodules from the water, and the nodules were dropped onto a belt conveyor which dumped them into a storage hopper.
The method of pumping used in the test was an air-lift system. Flow in the pipe is induced by continuous injection of air into the pipe at a depth of 1/3 to 1/2 the depth of the ocean.
