This means another complete layer of studies.

I think it's like a replacement layer. Remember, it wasn't that long ago that news came down the pike about the Supreme Court slapping the feds' hand for overstepping its bounds on environmental impact assessments (I'm linking below to Golfyeti's post that sparked some discussion on that topic). 

So some of that responsibility appears to be shifting to the Tahltan now. This could be a signal of how things will proceed in B.C. and perhaps other Canadian jurisdictions.

https://agoracom.com/ir/CopperFoxMetals/forums/discussion/topics/794876-environmental-impact-assessments-and-permitting-the-jurisdiction-of-provinces/messages/2395244#message