UK-based Stellar Diamonds has submitted its application for a mining licence for the Tongo project to the National Minerals Agency (NMA) of Sierra Leone.
After processing the application, NMA will forward it to the Minerals Advisory Board (MAB) for further consideration.
Following its consideration, the MAB will make its recommendation to the minister of mines for approval of the company's mining licence for the project.
Stellar Diamonds submitted the final environmental, social and health impact assessment (ESHIA) report to the environmental protection agency (EPA) for consideration.
Prior to EPA approving the ESIHA, public disclosure meetings would be held in 2016 in the project area, as well as in Freetown.
Later on, the required environmental licence will be issued for the Tongo project.
Stellar Diamonds chief executive Karl Smithson said: "The submission of the Tongo mining licence application and ESHIA marks a key milestone in the development of the project as we make the transition from exploration to mining.
"Notably, as far as I am aware, this is the first large-scale mining licence of any kind to be applied for since the onset of the Ebola crisis.
"As such this therefore also marks an important milestone for the country of Sierra Leone, which needs to attract new private sector investment to contribute to its post-Ebola economic recovery."
The Tongo mine is expected to require initial capital of about $24.8m for the first four years for development of both surface and underground operation.