Forrest's Fortescue Future Industries is about to develop hydro power installations in Papua New Guinea.
A two-tranche institutional placement is set to raise $100 million, 90% of which is underwritten, while a share placement plan is being launched for another $10 million.
Pricing for the new equity is $4.40 per share, a 19% discount on the stock's recent trading level at $5.42.
Hasting said the funding strengthens its balance sheet and places it in a strong position to finalise project financing for Yangibana as it targets plant commissioning by 2024.
Yangibana, located in the Gascoyne region of Western Australia, has a capital cost of around $660 million.
Various financing parties are reportedly interested in providing debt.
Hasting's prospects of being Australia's next rare earths producer were boosted last month when Forrest's Wyloo Metals provided $150 million in debt/convertible funding for the Australian Securities Exchange-listed company to buy a 22% stake in a Canadian company Neo Performance Materials.
Neo is a producer of magnets, specialty chemicals, and rare metals and compounds.
At its last traded share price of $5.42, Hastings was capitalised at $550 million.