An extreme example of ground freezing to control groundwater pollution from a closed mine, is the Giant Mine in the Northwest Territories, Canada. The full story is told at this link. In summary, it seems that in 1999 Giant Mine’s owner went bankrupt and so the taxpayer was left to pay to deal with a huge amount of toxic arsenic trioxide “disposed of” in the underground mine workings.

SRK was contracted to assess alternatives (56 of them) to deal with this problem. Seems they and the local community prefer this solution: simply freeze all the arsenic trioxide and the ground around it. This will be done using thermosyphons. I cannot copy the figures but urge you to access the links to see how bold and innovative this all is. I have only one question: will the taxpayer continue to operate this system forever?