1968 Volume 18 Issue 90 Pages 173-184
An undersea exploration has been carried out at the Taiheiyo Coal Mine since 1939, adopting the dredging, aqualung or sparker methods. From 1964 to 1967, seven offshore drillings were operated applying the single column or floating barge methods. The results of the explorations were as follows:
(1) By dredging, aqualung or sparker methods, the geologic structure of this undersea district was made clear.
(2) As a result of the explorations a new district called Minami-masuura was discovered to the cast of the present mining district where four offshore drillings had been worked. Thus, the presence of some favorable coal seams have been confirmed.
(3) By operating three more drillings some distance offshore from the present mining district, the uncertain geologic structure of the Higashi-masuura deep has been made clear as well as the presence of a fault, of which vertical throw is more than 200 meters. It was also confirmed that there are at least some favorable coal seams in each of the seven drillings.
