Hey Elemental
That's a "how long is a piece of string" question.
All I can tell you is that MEO have a unrisked value of $3.92 for Artemis.
You can see the methodology below.
Note that you have to use 25% instead of 20%, and change the share issue to 477,220,955
http://www.meoaustralia.com.au/icms_docs/59925_Clarification_to_2nd_September_2009_Good_Oil_Presentation.pdf