cross-posted from: slrpnk.net/post/22920153
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The melting Arctic permafrost is unleashing mining's 'toxic' legacy
Submitted 5 days ago by wolfyvegan@slrpnk.net to earthscience@mander.xyz
https://theweek.com/environment/the-melting-arctic-permafrost-is-unleashing-minings-toxic-legacy
Track_Shovel@slrpnk.net 5 days ago
This is a bit sensationalized in the way it’s written, but a lot of it is true.
The orange water is metal bearing water that forms when sulphide bearing rock is exposed to oxygen. With warmer temperatures the reactions are sped up. While it can occur naturally as they point out, in mining it’s from the overburden or waste rock being exposed where it was previously anoxic underground.
The tubes are called thermosyphons. They work by the aboveground part getting cooled by winter and conducting the cold in to the ground. Since arctic summers are short they result in net freezing.
Giant already has a freezing system to contain the arsenic trioxide but I believe this is to support it. It’s also passive.
The thing to point out is they do extensive thermal modeling and monitoring; same goes for water quality - they know with a pretty good degree of certainty what things will look like on the future. They over engineer things to increase certainty. For instance they’ll use RCP8.5 rather than RCP2.5 (less conservative) climate predictions and then plan and build for that.
Forever is a long long time which is why planning mines with the end in mind is important; however this concept is painfully new. Operators are constantly looking for closure solutions that will release them from a forever liability. These are those that are passive and don’t require perpetual water treatment. Operators these days - at least in Canada - are a different breed. Previously they didn’t know better, or were much less regulated.
I could go on, but I’ll cut it there