Ann: Appendix 3G - Exercise of Unquoted Options, page-13

Usually the option exercise takes 5-10 working days so whoever exercised these options would have set this in motion couple of weeks back atleast.
You need to send the money to the company, fill the form and send it to cosec then the directors have to approve and following that the options are converted to shares and put into your HIN/SRN. It is not instant.

Maybe they wanted the shares in their account before the drilling so that if the drilling results are solid and the price jumps then they can lock in gains. Alternately, they want to sell now and make 100% before uncertainty of drilling.