Csd average costs?, page-18

a little research later

one outdated but informative piece relating to production / costs / separation etc

http://www.carpentariaex.com.au/uploads/files/Magnetite-Information-Sheet.pdf

so   

1 ) there is a premium for  magnetite over heamatite

2) there is a further premium for pelletised magnetite

3) magnetite is increasingly preferred due to its better energy profile and lower impurities

4) most of the energy ( Bond Work) required to produce the magnetite would already have been used for Sn production ie the grind size used allows for magnetic separation from a water based slurry. Therefore  a greater profit margin on the magnetite component

and finally ( for now) Grange Resources  - recently reported that while iron ore prices sat at $60 a ton they received a premium of $20-30 US . They pelletise.