The company has commitments for $5 million from new and existing investors, including $1 million in loan conversations from managing director Tiger Brown, subject to shareholder approval.
In total, directors have offered $2.4 million of their own money, with the largest contributor being non-executive director Gerard King putting in $1 million cash.
Additionally, Astron is also looking for up to $3 million via a share placement plan.
The raisings are priced at 54c per CHESS depository interest, a 10% discount.
Blue Ocean Equities acted as lead manager.
The funding will be used to help upgrade the resource estimate, progress mining studies and plant design, and to advance approvals.
The Donald project has long been framed as a mineral sands operation recovering zircon and titanium dioxide products, and more recently the rare earth elements potential has been recognised, with plans to recover neodymium and praseodymium.
Resources at Donald, some 300km north-west of Melbourne, stand at 2.4 billion tonnes grading 4.8% heavy minerals.
A stage one feasibility study is due in the March quarter next year, examining a scaled back 7.5Mtpa operation that is intended to produce rare earth element and heavy mineral concentrates.
Production over the first five years is intended to be 285,000t HMC and 9000t REEC.
The rare earths are expected to generate around half the average annual revenue of some $285 million.
Plans for on-site separation have been paused, and the HMC will be shipped to a third party for processing, or in the company's processing facilities in China.
The aim has been to de-risk the development's in initial stage, which is expected to cost around $400 million.
Production is targeted for late 2025. Stage two could follow three years later.
Astron ended the last quarter with $2.5 million cash.
Astron's CDIs have traded at 28-95c over the past year and were last traded at 60c, valuing it at $73 million.