UPDATE 12pm: Shares in Mineral Resources and Aquila Resources have been placed in a trading halt pending an announcement about a "potential material corporate transaction".
Market chatter suggests MinRes is in the throes of putting together a merger proposal for Aquila to scupper a hostile joint takeover bid by China's Baosteel and Queensland-based rail operator Aurizon.
MinRes last week emerged with a 12.78 per cent stake in Aquila Resources after acquiring about 52.6 million shares for $3.75 each in a block sale from institutional holder M&G Investment Management.
Aquila was already the subject of a $1.4 billion joint takeover bid by Baosteel and Aurizon the put a value of $3.40 on Aquila shares.
Aquila is expected to reject the Baosteel offer in a target's statement to be released this week.
MinRes has already indicated it plans to work with Aquila to bring the company's 50 per cent owned West Pilbara iron ore project into production.
MinRes shares last traded on Friday for $9.55 while Aquila shares were off five cents, or 1.61 per cent to $3.13 before a trading halt was called.