1961 Volume 77 Issue 875 Pages 341-348
The Ube coal mine is developing the submarine coal seams belonging to the Tertiary formations. The coal field is divided into two areas by the Tsubuta fault, which runs nearly parallel to the shoreline under the sea bottom.
The underground water in the inside area which is cut by the Tsubuta fault, i. e. the area adjoining to the land is sea water type, which the water in the outside area is special type rich in HCO3.
The highly-pressed water flowing in the stratum above the coal seam somtimes breaks the roof of the working-face, which is protected by the draining bore-hole.