Considering that this move will save Capstone 15M of interest per year, only that makes it a pretty good move. 

It's also a first step that should allow them to keep a 50% ownership in their Santo Domingo at no cost by streaming gold with the same partner.

On top of that, they will be debt free and will be able to use the additional cash flow to create more shareholder value via high IRR projects.

You need to consider the big picture and value of money in time.  Unless Teck has more cash on hand, they would not be able to finance 100% of Schaft Creek by themselves.  Bankers will never take all the risk.

MoneyK