You ask 'Why does a board (of IRN) need a special authority by resolution to carry out duties which it is alrady is authorised to carry out under appropriate legislation?' The answer is in the ASX Listing Rules. You are correct in thinking that the general position under the Corporations Act is that the Board, not shareholders, manage the company. The Board does not need approval of shareholders to buy and sell assets and indeed can ignore a resolution passed in a shareholders' general meeting to do so. However the ASX Listing Rules impose additional limitations and obligations on listed companies. Rule 11.2 requires a listed company to have approval of shareholders for sale of its major asset.
What a mess this all is!
IRN Price at posting:
35.6¢ Sentiment: Sell Disclosure: Held