In this Sept. 25, 2012 photo, workers from the National Copper Mine Corporation, or Codelco, pose for a portrait as they wait for a bus home after a work day at the Chuquicamata copper mine in the ... more 
In this Sept. 25, 2012 photo, workers from the National Copper Mine Corporation, or Codelco, pose for a portrait as they wait for a bus home after a work day at 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) less 
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Associated Press | Photo By Jorge Saenz
Thu, Oct 11, 2012 2:42 PM EDT