Horizon Gold (ASX:HRN) said its definitive feasibility study (DFS) for its Gum Creek gold project in Western Australia has returned a pre-tax net present value of AU$1.31 billion at a 5% discount rate and an internal rate of return of 53.1%, according to a Wednesday Australian bourse filing.

The internal rate of return is based on a gold price of AU$5,500 per ounce, with a payback of 23 months from first production.

The company said the project targets average annual gold production of 98,000 ounces over the first five years and 880,000 ounces over a 10-year mine life, with first gold scheduled for the second half of 2028.

Pre-production capital cost is AU$350 million, including mine development, process plant and associated infrastructure, with pre-tax free cash flow of AU$1.85 billion and an all-in sustaining cost of AU$2,995 per ounce, the filing added.

The approvals process is on track for a final investment decision in the second quarter of 2027, it added.