Some relevant info from the ATO and from GXY below that may assist.
(Note; they caution reliance on this info and urge individuals to seek their own financial advice)
FWIW my understanding is that this merger will not realise a CGT event in my case, and I will simply recalculate my cost base (same overall $ but higher $ per share) when I receive my new ORE/MergeCo shares.
Not advice!
https://www.ato.gov.au/general/capital-gains-tax/shares,-units-and-similar-investments/takeovers-and-mergers,-scrip-for-scrip-rollover/
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https://wcsecure.weblink.com.au/pdf/GXY/02392012.pdf
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Hope that helps
DYOR