ABSTRACT

Cobalt crust resources have been found in 1,200 m water depth on the 5th Takuyou Seamount at 23N - 153W by researchers from Tokai University. The loose cobble type of deposits appear to be of economic interest and lend themselves to mining and processing using a CLB system with H202-H2S04 leaching. In this combination, both low capital cost and low risk have been projected for an estimated ROII of 39%. Recent developments in the CLB system described include a Ball Roller traction device and an Improved bucket dumping mechanism on the platform. The use of the CLB system IS proposed also for the removal and remediation of deepwater contaminated sites, the mining of placers and the recovery of sand deposits for coastal maintenance in moderate depths.

CRUST DEPOSIT ON 5TH TAKUYOU SEAMOUNT

The 5th Takuyou Seamount is a large guyot about 60 miles WSW of Minami Ton Shima, in the western Pacific. The plateau which is shallower than 1,500 m, covers about 3,000 km2 in an area some 30km by 100 km; the flanks of the seamount slope gently between 1,500 - 3,000 m and also cover about 3,000 km2 (Figure 1). Single line bucket dredging at nearly 50 stations resulted in the recovery of samples averaging about 100 Kg in each bucket without any loss of dredges. Photo-surveys of the bottom at depths between 1,130 m and 6,000 in indicated the considerable influence of depth on the bottom materials. Analysis of these data m Figure 2 indicates a predominance of nodules and cobbles on thin sediment between the depths of 1,130 - 1,200 m; a predominance of pavement at 2,000 m; and a predominance of nodules at 6,000 m.

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