Ann: Quarterly Cashflow Report-MNS.AX, page-7

It wouldn't be cheap to be digging up (drilling) and processing, purifying our graphite to send to end users for qualification activities.
Also they mention that they are carrying out development work with adding silicon etc which would require processed graphite to be used. Transport costs could be high moving around decent quantities.

IMO I don't think it is too high as it's not like they are all just sitting round the office pushing pens waiting for a signed off-take to appear in the inbox.