For the indigenous peoples in the high altitude Alto Loa valley of northern Chile, squeezing an existence out of a challenging environment is traditional and arduous. Situated in the Atacama Desert, one of the driest places on Earth, they have managed to sustain themselves and their culture for centuries thanks to the presence of the narrow Loa River, and their own ingenuity and determination. But as "A Letter to Codelco" shows, a rising resentment has partnered with that determination to survive and thrive.