SEGJ Technical Conference

Feasibility study for large-scale cavities at the abandoned mine using the exploration technique of cosmic ray muons

Abstract We develop the exploration technique for underground cavities with the exploration technique using cosmic ray muons. Those results are already reported in Ohnuma et al.(2009), Suzuki et al.(2009) and Suzuki et al.(2010). In this paper, we show the result that we tested in Ohya-ishi quarry to examine applicability for the cavity of the abandoned mine in the depth of the dozens of meters with the exploration technique using the cosmic ray muons. The anglular distribution of the cosmic ray muons was measured more than 30m under a cavity in the upper part in a deep gallery. We performed numerical calculation before the measurement and set parameters such as measurement time. As a result of experiment, the spacial resolution of depth is provided a one-tenth of the covering depth. This result shows that a exploration technique is possible for the large-scale cavity of the depth of dozens of meters. It is necessary to plan shortening of measurement time so that the measurement takes time at the depth of dozens of meters. We will apply the tomographic analysis in future to visualize the underground cavities.