Damauli, February 20 Illegal extraction of boulders, gravel and sand, among other river-related materials, from the Kaligandaki River has been going on unabated in Rising Rural Municipality, Tanahun district. Rampant extraction of river-borne materials has put the human settlement on the banks of the river at high risk. Locals complained that the authorities concerned did not take any action against those involved in illegal river mining. Chief Administrative Officer of the rural municipality Tirtha Raj Poudel said that his office was unaware about the illegal excavation of river-related materials. Assistant Chief District Officer Tulasi Ram Poudel, however, said that one excavator and a tipper had been taken under control after a team from his office reached the site. Superintendent of Police Siddhibikram Shah of Tanahun District Police Office said that the seized vehicles had been sent to the rural municipality office for further action.