Australian mining company Dart Mining has offered 3% Net Smelter Royalty (NSR) in the Unicorn project to US-based investor Red Kite for $8.5m.

Additionally, Red Kite will also invest $1.5m as equity into Dart Mining.

The investment is expected to be made in two installments with first tranche involving acquisition of 2% Unicorn project royalty for A$4.5m ($4.63m) and the subscription of A$800,000m ($823,000) for new Dart shares.

First tranche of the transaction is expected to be completed by 30 April 2013.

Second tranche, meanwhile, involves an option to acquire further 1% royalty in Unicorn project for A$4m ($4.1m) as well as the subscription of A$700,000m ($720,000) for additional Dart Mining shares.

Dart Mining managing director Lindsay Ward has stated that the agreement was preceded by a due diligence process that included thorough review of the mining methodology, plant design, geological model, environmental impacts and the financial assumptions of the Unicorn project.

"It will not only enable Dart Mining to accelerate the feasibility and approvals process, but it also sends a strong message to other potential Unicorn cornerstone investors and off-take partners that will be needed as Dart Mining moves forward with the Project," added Ward.

The execution of the second tranche of the transaction includes predefined conditions related to Unicorn project such as demonstrated progress with the pre-feasibility studies, which has to be satisfied by 31 October 2014.