mini fortescue, page-12

DSO = direct shipping ore

This means it doesn’t require beneficiation prior to shipment.

DSO will obviously save (money and time) on building a processing plant and reduce operating costs per tonne of product.

Steel mills prefer 62-64%Fe DSO as feedstock but seem to accept 55%+ as DSO these days depending of what the contaminants are.

Another thing to keep in mind some ore types are highly suited to beneficiation such as SRK’s while others require very expensive and energy intensive processing such as BIF hosted magnetite (GBG, ARH etc).