Mizunami Underground Research Laboratory Project, Compilation of results of geological investigation at the shafts and research galleries

Kawamoto, Koji; Kuboshima, Koji; Ishibashi, Masayuki; Tsuruta, Tadahiko  ; Sasao, Eiji   ; Ikeda, Koki; Mikake, Shinichiro ; Hara, Ikuo; Yamamoto, Masaru

This document presents the data of geological investigations in the shafts and research galleries to the depth of 300 m of the MIU from the 2004 fiscal year to the 2008 fiscal year. In the shafts and research galleries of the MIU, the Cretaceous Toki granite is unconformably overlain by the generally flat lying Miocene Mizunami Group (younging upwards from the Toki Lignite-bearing Formation to the Hongo and Akeyo Formations) with a depth of about 166 m to 168 m.