The investnorthwestbc website has the build at 2.5 years. This was using old information from the pre-feasibility.
Even so, I don't think I'd want to risk the deadline. (My experience with deadlines hasn't taught me to think they are solid.)
Quite apart from this 4-year thing it just makes solid financial sense to buy out the whole project and then split it up afterwards and bring in equity partners. There is no sense in keeping Copper Fox onboard when they won't be contributing any more money or any more financing.
I can't remember the details but Teck has some covenants in place to keep their debt ratio at a certain level. They can manage this whole deal so that they come out of it with partial ownership and no cost and little financing debt to profit. It just makes sense.
--http://investnorthwestbc.ca/major-projects-and-investment-opportunities/map-view/schaft-creek/schaft-creek-copper-gold-molybdenum-silver