Shares in Atlas Iron Ltd. jumped more than 22% by trading close on June 18 after Gina Rinehart's Hancock Prospecting Pty Ltd. lodged an off-market takeover bid to acquire the iron ore explorer, in which it owns a 19.6% stake.

Under the proposed all-cash deal, Atlas shareholders will receive 4.2 Australian cents per share held.

According to a same-day release, the iron ore explorer, which agreed to merge with Mineral Resources Ltd. in April, advised its shareholders to take no action on the latest offer.

Under the Mineral Resources offer, Atlas Iron shareholders would receive 1 Mineral Resources share for every 571 shares held, implying an offer price of 3.02 Australian cents per Atlas share at the time the deal was announced in April.

The offer is the latest in the struggle over acquiring Atlas Iron, with Fortescue Metals Group Ltd. building up a 19.9% stake earlier, which Australian analysts lauded as a smart play to keep Mineral Resources in check while effectively laying down "working capital" for growth options in lithium and base metals.

Fortescue expressed that under the current terms, it will not support the proposal.

Atlas recently disclosed that it received a notice from the office of the Minister for Transport, Planning and Lands that implied that its North West Infrastructure joint venture did not have priority to develop Stanley Point Berths three and four at Port Hedland in Western Australia.