There is a great concern in Japan how to deal with abandoned room and pillar mines, quarries as well as karstic caves following the 2011 Great East Japan Earthquake with a moment magnitude 9.0, which caused the collapses abandoned lignite and coalmines and underground stone quarries and associated damage to super structures at 316 localities in Tohoku Region of Japan. The authors have been involved the backfilling of an abandoned lignite mine beneath Kyowa Secondary School in Mitake Town, Gifu Prefecture, Japan against an anticipated mega earthquake. In this study, the authors present an integrated study on the backfilling of abandoned mine beneath the secondary school These studies involve the geological and geotechnical conditions, static and dynamic numerical analyses, monitoring before and after backfilling operations and some attempts of the verification of the effect of backfilling of the abandoned mine. The authors explain this unique integrated study and outcomes and findings from this study.
The extraction of lignite using the room and pillar mining technique was extensive in various parts of Japan until 1960s. These mines are abandoned and some of these areas have become urbanized since then. Tokai region in Central Japan is a well-known example for such a case. The Great East Japan Earthquake with a moment magnitude 9.0 caused the collapses abandoned lignite and coalmines and underground stone quarries and associated damage to super structures at 316 localities in Tohoku Region of Japan. There is now a great concern in Japan how to deal with potential damage resulting from the collapse of abandoned room and pillar mines, quarries as well as karstic caves in relation to the anticipated Nankai-Tonankai-Tokai mega earthquake. The anticipated magnitude would be similar to that of the Great East Japan earthquake, which occurred along the Tohoku region of Japan in 2011.
