A local geologist sent a letter to the local newspaper warning of what would happen if they tried to dewater the mine by punching a hole in the retaining wall at the bottom of the mine. He was right on.
I didn’t get to work on that case and am glad that I didn’t. Total EPA clusterf*ck. Reminds me of the Stringfellow case (lasted about 18-25 years). Another CERCLA screwup until the law was updated into reality.
A cement plug in the Gold King portal would have been a tacit admission that the mine was to be abandoned. Frankly the first step in reopening the mine would have been a dewatering program into a series of ponds where alkali additives could have raised the pH before release into Cement Creek which drains into the Animas.
Dewatering would have allowed geologists to map and sample the vein structures. This would have been followed by a drilling program. Frankly I don’t know why the owners didn’t promote this sort of program to a major mining company. Failure to find economic ore after such a program would have practically mandated a cement plug.
I’m really uncertain if Echo Bay ever came near the old Gold King workings as it was hard to tell on the tiny mine maps I’ve seen. It looks like they were very close and may have been below the old working which wouldn’t have dewatered the mine. If they did open the old workings, the water would have flowed in the Sunnyside workings and out the American Tunnel into Cement Creek.