Atlas shares closed at 3.6c on Friday and traded as high as 4.6c last Wednesday amid corporate interest by Mineral Resources, Hancock and Fortescue Metals Group.

Hancock said its offer represented a superior value proposal for Atlas shareholders relative to the previously announced scrip takeover by Mineral Resources, representing a 41% premium to the implied value of the MinRes proposal as of close of trading on Friday.

The offer has no minimum acceptance condition and is not conditional on due diligence, financing or regulatory approvals.

While the off-market offer will open in about two weeks' time, Hancock subsidiary Redstone Corporation, will be able to purchase shares on market from today.

Hancock revealed today that Redstone was incorporated in April with the principal purpose of making the Atlas offer.

Hancock already owns 19.96% on Atlas after acquisitions earlier this month.

Hancock executive director Tad Watroba said the Atlas assets has long‐term synergies with other iron ore assets in Hancock's portfolio.

"There is potential to unlock value through the future development of Atlas resources as part of our wider system of operations," he said.

"If we obtain control of Atlas, we intend to conduct a strategic review to better understand the most appropriate time and means to develop and integrate Atlas into the existing operations of the Hancock Group.

"The Hancock Group iron ore interests produce iron ore products that are priced off the 62% index. Some of the Atlas deposits contain elements that have complementary characteristics providing optionality and opportunity to improve the non‐iron elements of ore quality further.

"The remainder of the Atlas resources could serve to extend the life of existing Hancock iron ore interests."

Hancock said it intended to maintain the status quo, including current operations and employees, in the short-term but did not rule out suspending production or divesting non-core assets following the review.

There was no reference to port infrastructure in the 49-page bidder's statement.

Hancock owns 70% of the 55 million tonne per annum Roy Hill mine, a 50% stake in Rio Tinto's 45Mtpa Hope Downs mine, and the undeveloped Mulga Downs iron ore project.

Atlas said it would evaluate the offer, and its impact on the MinRes scheme of arrangement.

The company has told shareholders to take no action until the board weighs up the offer.

FMG CEO Elizabeth Gaines noted the takeover announcement.

"We will continue to assess our strategic options and do not propose to make any further comment at this time," she said.

Shares in Atlas closed 22.2% higher at 4.4c, slightly above the offer price.