ABSTRACT:

The continuous line bucket (CLB) system has been improved by combining the techniques of the Turning CLB and Hydrodynamic Separation. The cost of mining nodules from the Cook Islands, or similar deposits, at 5,000 m depths at a rate of 1,000 tons/day, is estimated to be US$69, which is favorably competitive with the cost of mining by hydraulic systems. Processing of nodules using a sulphuric acid leach is costed at US$ 112/L The value of one too of processed high grade nodules is estimated to be US$ 319 for a 4 metal operation. Compared to other mining methods such as suction pump mining and single trawl mining, the CLB appears superior in its mechanical simplicity and low power requirement. Its use for the mining of crust and placer deposits also appears feasible.

INTRODUCTION

Since its conception in 1968 by Yoshio Masuda, the continuous line bucket (CLB) sys1em for deep seabed mining has undergone a number of sea trials. Of prime importance were the tests off Tahiti in 1970 from the R/V Chiyoda Maru No.2 (Masuda et al 1971), and off Hawaii in 1972 from the 16,000 too vessel Kyokuyo Maru No2, conducted by an international group (Masuda, 1982) under the direction of Dr. John L. Mero (Figures 1 & 2). Another series of tests were carried out near Japan in 1987 by Japan Resources Association to successfully lesl the Turning CLB (TCLB). Rich deposits of metalliferous nodules have been found on the deep seabeds in the Pacific at depths of 5,000 m in the Clarion Clipperton Fracture Zone (CCZ), and the Exclusive Economic Zone of the Cook Islands, and in the mid-Indian Ocean. Rich deposits of metalliferous crusts have been found of sea-mounts near Minami-Torishima Island (Japan), Johnston Island (USA), and the Republic of the Marshall Islands.

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