Key events leading up to massive Colorado mine waste spill

AP News
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Posted: Oct 22, 2015 6:46 PM

A U.S. Interior Department investigation released Thursday said the Environmental Protection Agency could have prevented a 3-million-gallon wastewater spill from a Colorado mine in August. The Bureau of Reclamation, which is part of Interior, provided this timeline of events concerning cleanup of the long-inactive Gold King Mine in southwest Colorado:

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2009: Concerned that a cave-in was holding back water inside the mine that might someday burst out, Colorado tries pushing a pipe through the debris to relieve the pressure.

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2014: The state asks the EPA to reopen and stabilize the mine entrance because erosion from the hillside above has covered the pipe.

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Sept. 11, 2014: The EPA starts excavating the mine opening, but it stops because water begins to seep out, and a nearby holding pond might not be big enough. With winter approaching, work is halted until 2015.

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July 14, 2015: EPA returns to the site.

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About July 23: The EPA's on-scene coordinator asks a Bureau of Reclamation official to visit the mine because the coordinator is unsure about plans to drain water. The visit is scheduled for Aug. 14 because the EPA official is going on vacation.

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Aug. 5: A different EPA on-scene coordinator, filling in for the one on vacation, is at the site. EPA and state officials agree to insert a pipe downward through the debris covering the mine opening to reach water inside and begin pumping it out. About 11 a.m., water begins spurting through the debris and then becomes a torrent. Eventually, 3 million gallons escape.

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Aug. 24: An EPA internal review concludes the blowout "was likely inevitable."

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Oct. 22: The Bureau of Reclamation report says the EPA underestimated how much water was inside the mine. The report said the blowout could have been avoided if the EPA had drilled into the mine from above, measured how much water was inside and then revised its plan accordingly.