RE:Santander vs CaribouMany ways to look at this, but I would not agree with selling off a great operation like Santander. It's low cost and cash flow positive. That cash flow, along with Caribou's, should be able to repay the debt in normal course. Recoeries and grades go up and down all the time, as different mine zones are mined, etc. No need to start selling off great assets to repay debt, as debt isn't necessarily bad.
Plus, Caribou isn't fully optimized yet, and therefore, there's still some risk associated with it. You've mentioned a lot of good things about Caribou and the New Brunswick area, and I agree but why sell off a zinc asset today - - especially when pretty sure the price of zinc TV is going up tomorrow. Any valuation would likely be done at a forecast zince price and any buyer is not going to use the price you're using in your forecast if you know what I mean.
TV is just in the progress of getting re-rated, now that the second mine has been somewhat de-risked. But it would be silly and way too premature to sell today. The bottom line is that I and many other investors (maybe you too) are in the TV stock because we beleive in the zinc story. If that's the case, then you want to have as much zinc production as possible. You want to have more mines, more production, thereby lessening overall company risk. Nobody wants TV to be a one-trick pony.
As long as they can manage the debt, it's not an unreasonable amount.