(Brennan Linsley | The Associated Press) In this Aug. 13, 2015 file photo, wastewater flows down a trough, right, from the site of the blowout at the Gold King mine which triggered a major spill of toxic wastewater, outside Silverton, Colo. Crumbling mine tunnels awash with polluted waters perforate the Colorado mountains, and scientists may one day send robots creeping through the pitch-black passages to study the mysterious currents that sometimes burst to the surface with devastating effects.