The funding is being sought by selling new shares priced at 62c each, according to a terms sheet sent to investors.

At the 69c the stock was trading at prior to going into a trading halt for the current raising, Highfield was capitalised at $250 million.

Proceeds of the current raising are earmarked for early work activities at Muga and the finalisation of debt facilities, as well as for progressing negotiations with strategic investors and general working capital.

The company needs to find about $700 million for the first phase development of Muga, and another $350 million for the second stage.

At full production the company is promoting annual earnings of nearly $650 million (on an EBITDA basis).

The company acquired potash assets in northern Spain soon after listing more than a decade ago.

Highfield's major shareholder is Owen Hegarty's EMR Capital.