Ann: HY20 results conference call, page-3

Mitchell Services (MSV) and Capital Drilling (CAPD) are your best guides to valuation.
From my estimates they trade between 3.5x (Capital - based in Africa) and 4.5x (MSV)
If we place SWK on the mid-point (4.0x) and use FY21 estimates as "sustainable" (my estimate is $35m) then Drilling is worth $140m.
Even on FY20 guidance (=FY19 or $28m) this would imply $112m
Either way, well above curent share price, then we have OreExplore and excess franking credits