Abstract :

Since 1975, Metal Mining Agency of Japan (MMAJ) has been surveyed of mineral resources on deep-sea floor: manganese nodules, submarine hydrothermal deposits and cobalt-rich manganese crust deposit. For more effective survey, Deep-sea Boring Machine System (BMS) has been developed by MMAJ. BMS has capability of20m coring under 6,000m in water depth. The size of BMS is 3.6 meters wide, 4.4 meters long, 5.5 meters high and the weight is 4.5 tons in air. BMS has three legs and can keep the upright position up to 20 degree inclination. This paper describes the outlines of BMS and the result of core boring at the maximum depth of1986m in Northern Mariana Area.

Introduction

Since 1975, Metal Mining Agency Japan (MMAJ) has performed the survey of submarine mineral resources; manganese nodule(1975-), seafloor hydrothermal deposit(1985-) and cobaltrich manganese deposit(1987-). MMAJ has been working on development of a survey system for submarine mineral resources since then. In the survey of seafloor hydrothermal deposit and cobalt-rich manganese deposit, the vertical distribution of mineral is required for analysis and evaluation of the deposits. For the subsurface sampling of seafloor rock, one of the most effective methods is the core sampling by a drilling machine. Based on the investigation, in 1994 MMAJ started the development of Boring Machine System (BMS) which has capacity of 20m core drilling at a depth of 6000m(Figure 1). The whole system including BMS and other subsystems was completed in 1996. In this paper, the outline of BMS and results of drilling at the Northern Mariana Area are described.

Previous development of sea Door boring machine

Several submerged boring machines were developed during 1960s and 1970s by such organization as the Geological survey of Japan, the Institute of Geological Sciences (U.K.) and the Bedford Institute of Oceanography (Canada).

This content is only available via PDF.
You can access this article if you purchase or spend a download.