The project, previously called the Fifteen Mile Stream, will utilise conventional gravity and carbon in leach cyanidation techniques to produce gold dore bars, replacing the flotation and gravity concentrates method.
The processing decision will allow for the reuse of the existing Touquoy processing plant, helping to drive down capital expenditure costs and improving overall gold recoveries from direct whole ore leach instead of leaching of concentrates, the company said.
Additionally, the revised design layout will create minimal disturbance while boosting capital and operating cost efficiency.
"With this strong prefeasibility result, St Barbara will now focus on the preparation of an updated environmental and social impact assessment for this new standalone design of the 15 Mile project," said Andrew Strelein, managing director and chief executive.
He went on to note that the development will provide "hundreds" of well-paid jobs for residents while also remediating the historical tailings at the site.
"The feasibility study engineering is intended to be ramped up as we see progress towards environmental approval with the commencement of development entirely achievable in mid-calendar 2026," said Strelein.
Tailings management
Earlier this year, St Barbara received information requests from the Nova Scotian Minister of Environment and Climate Change regarding the environmental assessment of the proposal to deposit tailings into the Touquoy open pit.
The request followed concerns raised by some environmental groups and locals about the potential ecological impacts of the mine, including the disposal of tailings in the open pit.
The proposed method would deposit tailings from 15 Mile into the pit and then cover them with waste rock to reduce the risk of acid rock drainage and erosion.
In the statement, the company explained that the method was ideal because it reduces the environmental impact by eliminating the need for a new tailings dam.