Boat crews descend into deep tunnel to remove 18 years of trash
In this Sept. 25, 2012 photo, a drilled tunnel crosses under the Chuquicamata copper mine in the Atacama desert in northern Chile. Experts say that by 2019 the Chuquicamata copper mine will be unprofitable, so state-owned mining company Codelco is trying to head off closure by converting the open pit into the world's largest underground mine. Codelco believes the mine still has much more to give, with reserves equal to about 60 percent of all the copper exploited in the mine's history still buried deep beneath the crater. (AP Photo/Jorge Saenz) Image by The Associated Press
Three boats were lowered into the bottom end of the deep tunnel system Wednesday to begin removing plastic trash, wood and other floating debris that has collected since the wastewater storage cavern was put into service in 1994.