This leads me to think that there is something in the works that could be very large... no other reason why they are this quiet about it

When something is material it means that the information could reasonably be thought to affect the stock price of the issuer. What Teck is saying is that none of the work they are doing with SC could affect their stock price and that is why they are not required to report on it.

Whereas for Copper Fox everything they do on SC might have an effect on our stock price so Copper Fox reports it in a NR.

I think the only time Teck reported on SC was when the JV was announced.