Twin Metals decision to switch to dry stack tailings method means any sulfur/sulfide is nearly non-existent while dam failure is officially non-existent

by Bob Colombo
July 18 changed the landscape for non-ferrous mining in the Arrowhead. An innocuous sentence in our morning Facebook page simply said; “TMM to use Dry Stack Tailings.” I read it and whispered to no one, Thank you Jesus and Kelly Osborne. The importance of that sentence is huge.
World-wide there are 3,700 earthen dams in the mining industry. Chile alone has 740 dams and most of them are sitting over, or near, one of the most active earthquake faults in the world. In the last four years, I’ve have been witness to two major dam blowouts in Brazil. They were iron mines in the state of Minas Gerais and both are little more than an hour away from my home. Is it any wonder why new methods of dealing with tailings have been a hot-button issue for years? Tailings dams are basically the world’s biggest mud puddles with the consistency of wet cement.
Imagine if you could squeeze the water out of that mud to a level that would allow you to move the dehydrated commodity on a conveyor belt like it was damp sand. That’s the premise of DST. The sand could now be placed on massive water proof pads and any external water (rain, snowmelt) would be collected, processed and fed back into the closed-loop water system of the mine.
Simple genius; that’s what DST is in a nut shell. If you were to ask the CEO of any mining company what keeps them up at night they would say it’s those damn dams.
The Arrowhead is fortunate to have two, non-ferrous mines moving through the permitting system. TMM owned by the Chilean miner Antofagasta and PolyMet owned by Swiss based miner, Glencore. TMM had more freedom to handle mine tails while PolyMet’s options seemed limited. While TMM has the convenience of building their DST system into a new, green-field mine, PolyMet had to deal with a brown-field mine (a previously mined property) and will utilize much of the infrastructure left in place by the former LTV.
It doesn’t take a lot of imagination to realize that investing a billion dollars or more into this well-worn, used mine would qualify PolyMet to receive some recognition for recycling on a grand scale. You would think that both of these mines would have the full support of the state of Minnesota, but that doesn’t seem to be the case, does it.
In the rebuttal that followed the TMM news, Becky Rom from Save the Boundary Waters replied immediately. There was no caterwauling and her comments were heavily perfumed with nervous angst. Ms. Rom stated she is openly frustrated that the TMM project even got this far. She continued that in 2016 the USFS declared the mine posed a risk to the B’dub and the risk remains.
However, TMM’s decision to eliminate the dam has, by default, eliminated any risk. With no dam there will be no wet muck and no flowing tailings. At its worst, the sulfur content of any exposed material will be .12 to .15%. That’s virtually nothing when compared to other copper ores that can contain more than 30% sulfur.
I’m a fan of both the EPA and the USFS, but in the last few decades, both agencies have become highly compromised by highly aggressive environmentalism.
Ms. Rom continued: today’s announcement actually makes things worse. How can that be possible, Becky? Listen to what TMM is saying. The tailings basin isn’t going to be moved, it’s going to be removed.
Ms. Rom closes with: “Minnesotans can’t rely on hollow promises from an international mining company with a history of environmental degradation and political; corruption to protect the B’dub.”
That statement is just nonsense; the truth is this. The State of Minnesota enforces laws and regulations that are the mining industry bellwether. Whatever your personal opinions might be of any mining company Ms. Rom, are quite honestly, irrelevant. It will actually be the state of Minnesota and their inspectors to oversee compliance. It will be the state mine inspector who will administer any and all citations to the miner.
In all fairness; I can’t imagine the state treating any miner, foreign or domestic, any differently when overseeing mine operations. While MSHA oversees human safety on the mine-site, it is the state that oversees environmental compliance and it doesn’t matter if the miner is from Chile or China or Minnesota or Mars, they are all scrutinized equally.
Last summer, Jim Maki and I poured through maps in his bait shop looking for lakes deeper than 200 feet; we found none. TMM has noted that the highest dome (roof) of the mine will be more than 400 feet below the surface so there is no chance of lake water migrating into the mine; drilling results indicate that this will be a dry mine. The desired minerals are in veins that lay within a rock composite that is virtually sulfide free. Unlike a surface mine where the entire pit gets dug-out, the underground miner can “chase veins” by using quick assays between blasts and adjusting the drill preferences to get the best results after each shot.
The benefits of DST are posted all over Facebook, on TV and in the print media, but a two issues need to be exposed since I haven’t seen it mentioned. The escrow account that the state demands from the miner to cover catastrophic dam failure should be greatly lowered. With DST now the choice of the miner, the catastrophic failure fund should be a fraction of what was required when the tails dam was a possibility. Really; the State needs to shrink that account substantially.
The state knows that DST is currently doable for smaller, boutique mines. I’m sure as the years tick by, the system will be refined to accommodate larger mines. Going forward, the state should require that future miners be required to utilize DST systems in their initial mine plan. By eliminating conventional up-stream, down-stream and centerline tailings dams, the state would go a long way in protecting the rich waterways of northern Minnesota.
I can’t help but wonder about Ms. Rom and her posse comitatus. After 10 years of chasing the rabbit down the wrong hole, how does she explain to her elected supporters that she blew it?
Many powerful people in DC and St. Paul are wiping egg off their face since the twenty-year battle cry has been “it’s the sulfur and the dam, stupid.” They are waking up to the truth; Becky was wrong all along. Not her fault, just a lack of knowledge about modern mining best practices.
Any sulfur/sulfide is nearly non-existent while dam failure is officially non- existent.
If she attacks with new perceived threats, they would not be believable. Who can trust her now? She got played. She and her minions treated that which was salient as if it were nonsense; a major snafu.
The miner admits they studied DST but didn’t know they would embrace DST. They just didn’t include it in any narrative and seemingly kept it under wraps. And why wouldn’t they? They let Becky and company burn all their energy, equity, integrity and time chasing the rabbit down the wrong hole.
Twenty years of environmental war killed with one simple sentence. Becky might improve her lot next time with better prepared experts who know all they can about modern mining’s best practice and newest technology.