The company issued 12.5 million at 80c per share, a 15.8% to yesterday's closing price of 95c.
RBC Capital Markets was lead manager to the placement.
AustralianSuper participated in the offer and will increase its stake in Agrimin from 10.9% to 14%.
Agrimin already had $6.4 million cash as of June 1.
The proceeds will be used for the Mackay DFS, advancing the proposed logistics infrastructure and for working capital.
A prefeasibility study completed in May outlined a 20-year operation producing 426,000 tonnes per annum of sulphate of potash at all-in sustaining costs of US$256 per tonne.
Capital costs were estimated at $409 million.
Using a SOP price of $555/t, the project would generate annual EBITDA of $137 million per year.