I wouldn't worry too much about trucking ore 260 km. At present it costs about $17/tonne to truck to Kalgoorlie. So it would only add an extra $19 (?) to truck 260km.
Toll treatment costs are going up, now about $50/tonne. I dont know what profit mills make but KWR/BTR would only have to find a saving of about $15/tonne in treatment costs to make the venture worthwhile.
Seeing the wars that have been fought over mill ownerships and disputed recoveries recently, having control over treatment is worth a small premium. Saves a lot of argument and allows you to treat anyway you like, and lower local grade to keep the mill ticking over.
KWR Price at posting:
3.4¢ Sentiment: None Disclosure: Not Held