Stability investigation of the foundation around mill tailing yard

Hasegawa, Osanu*; Takano, Hitoshi*

In order to evaluate the possibility of slope failure and landsliding, aerial photograph interpretation has been carried out around mill tailing and waste rock yards.Almost of small-scale slope failure features are recognized in steep slope area (over 20 dip), in which Cretaceous granitic rocks and Tertiary volcanic rocks are distributed. Furthermore small-scale slope failure features are also recognized in artificially deforested area. Therefore it seems that many factors are related to occurrence of slope failure.Landslide features are recognized at 2 localities in the distribution of Tertiary stratified volcanic rocks. The landslide may be closely related to the geological setting. In addition, these slope failure and landslide topographic features have no relation to lineament or active fault. Mill tailing and waste rock yards are especially located in gently slope area (under 20 dip). It is suggested that these yards are topographically on stable landform. Although, there exist steep gradient slopes (over 20 dip) at upward of Choja and Kannokura waste rock yards. And slope failure features are recognized around these yards. Therefore it may be inferred that slope failure will take place there.