"Gravelle stated Cliffs Natural Resources vice-president William Boor testified that 60 per cent of the ore is projected to be refined in Canada, with 40 per cent of the concentrate exported abroad to help pay for operations."
This is a section out of http://www.northernlife.ca/news/localNews/2012/02/15-gravelle-ring-fire-sudbury.aspx
IMO If you read between the lines, 40% could come from BD which can be shipped directly to market