The magnetite is a good grade and it's in an emerging patch.
Current Price is around $140 a tonne.
With magnetite estimates in the billions of tonnes here, it's untold what the 40% stake is worth.
Heaps of factors to take into account, processing etc but I don't think MEP would let it go cheap, that is if Mutooroo is the asset for sale.
i would have a guess at the sale being well in excess of the current market cap.