Cornwall Resources is the joint venture vehicle holding the Redmoor tin and tungsten project located in Cornwall.
Binding contracts have now been signed, with an agreed settlement date of 30 May 2019.
The consideration of A$5mln will be paid progressively, with the first A$2mln due on settlement scheduled for 30 May 2019.
A further A$1mln will be due on 29 November 2019, with the following payments related to performance targets.
"SML and NAE have worked closely together to prepare final documentation for SML's purchase of NAE's 50% holding in Cornwall Resources Limited,” said John Peters, managing director of Strategic Minerals.
"Recent developments have shown the potential for the Redmoor tin and tungsten project to be a world class mine and, with the full control of the project, SML believes it can time its development to fit in with cash flows from Cobre and, shortly, Leigh Creek. This ability to manage cash flow requirements provides great confidence that the Redmoor project will progress in the future."