So what data is he basing this on? Can anyone advise ?

The Ring contains mostly economically unproven amounts of chromite – a critical mineral used in the production of stainless steel. While studies of the potential environmental impact of the access road are continuing, there have been no commitments from either Ottawa or the Ontario government to build it.

full news release :

https://www.theglobeandmail.com/business/article-ontario-wades-into-critical-minerals-sector-but-curbs-enthusiasm-on/