Directors of Waymouth Street-headquartered exploratory miner Rex Minerals have unanimously recommended shareholders accept the takeover offer from a subsidiary of an Indonesian mining giant, which valued the firm at $393 million.

Under the deal, MACH Metals Australia will acquire all of the shares it does not already own in Rex Minerals at $0.47 per share.

The offer price implies an equity value of $393 million and represents a 79 per cent premium for Rex shareholders.

MACH – a subsidiary of Indonesian conglomerate Salim Group – currently owns 15.8 per cent of Rex’s issued equity.

Rex said the offer was received following a competitive global partnering process focusing on the $854 million funding and development pathway for its Hillside project in South Australia, 12km south of Ardrossan.

Once operational, Hillside will be an open pit mine on an undeveloped copper and gold site and is dubbed the “re-birth of the copper industry on the Yorke Peninsula” by Rex.

Rex – the 52nd largest company in the state per the 2023 South Australian Business Index – received all necessary government approvals for its Hillside project in March 2022. The mine will sit on prime farmland in central Yorke Peninsula.

The project has faced community opposition during its development, with locals raising concerns about mining exploration rules on productive agricultural farmland. Shack owners at holiday beach Black Point – about 9km from the proposed mine – also opposed the plan.

Spurred by the community’s response to Hillside, a select committee into land access provisions for mining companies under the state Mining Act was established in 2021, led by then-crossbench MPs Fraser Ellis, Sam Duluk and Troy Bell alongside then-Labor Opposition and independents Geoff Brock and Frances Bedford.

Today, Rex CEO Richard Laufmann said the proposed deal was an opportunity for shareholders to “realise their investment at a 10-year historical share price high”.

“This transaction also represents a more certain outcome for wider stakeholders in Hillside, including the local community, the South Australian government and Rex employees who will benefit from the significant financial strength and proven track record of MACH to deliver the successful development of Hillside,” Laufmann said.

“The South Australian Government has been a leader in Australia in support of decarbonisation and copper development. The successful development of Hillside will very much align with their strategy.”

Rex non-executive chairman Ian Smith said the transaction was a “great outcome for shareholders”.

“The MACH offer is the culmination of many years of hard work and delivers certain value for shareholders,” Smith said.

MACH managing director Ferdian Purnamasidi said he was enthusiastic about the acquisition of the copper project.

“We are excited to continue the development of the Hillside project, which aligns with our strategy to diversify our asset portfolio,” Purnamasidi said.

“Our strong focus on copper is critical to the energy transition process.

“We remain committed to advancing the excellent work undertaken by Rex on the Yorke Peninsula, including supporting the local workforce and the broader Yorke Peninsula community throughout the ownership transition.”

The deal remains subject to approvals from shareholders, the Foreign Investment Review Board, an independent expert and the courts.

Shareholders will meet in October this year to vote on the deal. If passed, the transaction will be implemented later that month.

Shares in Rex Minerals are up by 63.64 per cent to $0.45 per share in early trade.