Continue spills at tailings facilities. In scientific literature there are reported 70 cases in world. Recently there was one mine spill at river Sonora-Mexico.

Abandoned mine-related facilities could be the potential threat for nearby areas. They were abandoned at early years when no restricted regulation was established. Inspection for those places might be needed on a regular basis before those spills of AMD turns into a regional disaster like this as well as like somewhere you mentioned at Sonora Mexico.

Sometimes a phenom natural exceed design norm. Recently development emerging technologies change ratio solid and liquid in tailings (for example paste tailings), for prevent accidents and protect environment.

The latest technology of reducing moisture content in tailing does help on preventing accidents happening like this case in US. I think EPA may need to conduct a comprehensive investigation over all historical abandoned sites before another disaster happened.

The Animas River accident had nothing to do with tailings. It was water on a multi-level mine impounded behind failed rock and backfill in the main audit.

Thanks for the correction. Any ideas for preventing such disaster happening again in similar situation. I believe this Gold King mine is not only site with this problem.

Oh, sure. As shown from the closely proximate (and very much larger total affected mining zone) American Tunnel system, properly engineered and constructed bulkheads can control the pressures. It requires a serious effort coupling geology, mine-mapping, surface water hydrology, hydrogeology and rock mechanics to do the job properly. That was done for American Tunnel and the workings it drains, but was not undertaken for Gold King.

Given that the Gold King is directly above the American Tunnel, and the mine pool in the Sunnyside was known to have been 300 ftamsl higher than the Gold King entrance in 2001, the possibility that bulk heading the Sunnyside caused the build up of water behind the Gold King is worth pondering.

Then you will need to get all the maps, geologic as well as mining, plus all the records of piezometric conditions and flows. I don't think one can just take those elevations, absent the structural geology and the water data, and say anything of the sort. Not in a technically responsible manner.

INAP and ADTI-MMS met with the Animas River Stakeholder watershed group at CH2MHill in Englewood Colorado to brainstorm innovative solutions to the problem which were provided by sponsoring a contest (Innovative Challenge). A conventional high density sludge water treatment plant would likely meet their discharge standards. The pond system currently in place is a step in that direction. 

It is a complex problem, no doubt, with many potential contributing factors and lots of unknowns within the drainage. Maps may not be complete, illegal connections, and connections caused by collapsed workings, may have rested in a stronger hydrologic connection between the Sunnyside and the Gold King. However, it is well acknowledged on EPA's Red and Bonita OSC page that flows from the Mogul (subsequently bulk headed) and Red Bonita (bulkhead was planned for completion this fall), all in the same area, increased following the sealing of the Sunnyside. The water has to go somewhere.

Thank you for sharing those ideas for preventing such tragedy in similar situation. Also, as you present the outcome that installation of bulkhead is working on pressure control, the Gold King, as a bad example, indicates bulkhead would be a good solution. I learnt a lot from your sharing.

Video of the event remarkable

https://www.facebook.com/Mark.Douglas.Canfield/videos/1648111835426695/?pnref=story