ABSTRACT
Slope failure of portion of overburden dump at 4130 m level on May 4, 2000 has caused approximately 150,000 m3 overburden (OB) material to enter Wanagon Basin. This event resulted in the collapse of water and mud retaining wall at the outlet of the lake basin, which further triggered failure at toe of the overburden dump. This failure sequence has resulted in approximately 600,000 m3 of mud to flow out of the basin to enter Wanagon river in the form of debris flow and flood reaching 10 m above normal elevation.
