The study of groundwater flow systems in bedrock is very important in assessing the reliability of underground facilities in the deep bedrock.
About the results of examinations now going on in the crystalline bedrock at the Ohmine 550m level drift and KH-1 borehole in the Kamaishi Mine, Iwate prefecture, this paper, part 1, deals with the groundwater chemistry in the deep crystalline bedrock. The Ohmine 550m level drift is located in the northern part of the Kamaishi Mine and Kurihashi granodiorite, Ganidake diorite and skarn minerals are distributed there.
The results of this study are summarized as follows :
1) Water chemistry of the groundwater around the Ohmine 550m level drift in the Kamaishi Mine is classified into six types by Piper's expression, which are also supported other interpretation methods for groundwater chemistry.
2) Water chemistry of the drained groundwater into the drift has some relationship with the fracture distribution frequency of the bedrock.
3) From the results of the multivariate analysis for the groundwater chemistry, the effect of eluviated chemical component from mineralized Ganidake diorite and skarn contribute to the most of the groundwater chemistry in the studied area. Also in the Kurihashi granodiorite, ionic exchange reactions contribute to its groundwater chemistry.