The Gilt Edge Mine Superfund site in South Dakota is the topic of a just published US Environmental Protection Agency proposed plan regarding closure.   The mine is also the topic of a longer posting on determination of the site water balance by stochastic methods published at this link.

In summary this is an old mine, dating from the late 1800s and continuing in various guises through the 1900s.  Now it is closed and a potential source of acid rock drainage.  Thus the decision to put it on the Superfund list and the need to determine how to cope with extreme rainfall events that may add lots of water to the system and lead to lots of excess acidic runoff. 

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For two excellent technical papers on the engineering reasons for the failure of the walls leading to flooding of New Orleans as a result of Katrina, see the Rocscience papers.  Not quite mining-specific, but the lessons learnt are applicable: soil shrinkage leading to a shortening of the groundwater seepage/flow path and hence forces not accounted for in the design—hence failure. 

Which leads to a rumination on the old idea propounded by Terzaghi and Peck: it is the small, undetected geological or geotechnical feature that leads to failure of soil and rock structures.   Typical mining instances in which this occurs include the typical open pit rock slope failure, the bursting of pillars in underground mines, and the tailings impoundment that is overtopped or which suffers foundation failure as a result of piping. 

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