Horizon Gold Defines Path to 2028 Production for Gum Creek Project

Horizon Gold (ASX: HRN) has completed a definitive feasibility study (DFS) that sets a development pathway for its wholly owned Gum Creek gold project in Western Australia, targeting first gold in the second half of 2028.

The open-pit plan targets 25.1 million tonnes at 1.19 grams per tonne gold for 962,000 mined ounces, with 880,000oz recovered across an initial 10-year mine life and average production of 98,000ozpa during the first five years.

Gum Creek requires $350 million of pre-production capital and, at a base-case gold price of $5,500 /oz, is forecast to generate $1,854m of pre-tax free cash flow, a $1,307m pre-tax net present value and a 53.1% internal rate of return.

The DFS supports a final investment decision (FID) in the second quarter of 2027, subject to funding and approvals, with plant construction scheduled to begin in the fourth quarter of that year.

Horizon appointed Orimco Pty Ltd as project finance adviser in July 2026, and plans formal engagement with Australian and international financial institutions as it advances approvals and detailed engineering.

Probable Ore Reserve Key

A maiden Probable ore reserve of 18.2Mt at 1.24g/t gold for 728,000oz underpins 76% of the production target, while Indicated resource ounces outside the reserve contribute 18% and Inferred resource ounces account for 6%.

The first five years are underpinned by about 97% Probable ore reserve ounces and 3% Inferred mineral resource ounces, but the latter carry low geological confidence and there is no certainty they will convert to Indicated status or that the production target will be realised.

Average production across the mine life is forecast at 88,000 ounces per annum, peaking at 114,000oz in year two, with an all-in sustaining cost of $2,995/oz.

Around 78% of the target comes from the Gidgee Shear Zone and Howards mining areas, while the remaining ore sources sit within 48 kilometres of the proposed mill.

The project remains most sensitive to the gold price, although modelling at $4,000/oz returned a pre-tax NPV of $335m, a 19.5% IRR and $569m of free cash flow across the mine life.

Conventional CIL Processing

Designed to produce 2.4Mtpa, the proposed plant will use conventional three-stage crushing, single-stage ball milling, gravity recovery and carbon-in-leach (CIL) processing, with overall gold recovery forecast at 91.5%.

Horizon has designed the crushing and milling circuits for a potential expansion to 3.0Mtpa through larger crushers, a reserved footprint for a second mill, and space for additional leach and adsorption tanks.

Process plant expenditure accounts for $159m of pre-production capital and non-process infrastructure contributes $114.1m, while the total includes a $30.4m contingency and commissioning costs.

Existing roads, an operating airstrip, potable water, and a 50-person camp provide a base for early works, with plans to expand existing accommodation and construct a new 252-person village.

Early accommodation work is scheduled from the third quarter of 2026, site works from early 2027 and process plant contractor engagement by the second quarter of 2027 before construction mobilisation in the fourth quarter.

Optionality from Underground

The open-pit case excludes 416,000oz of free-milling underground resources grading 3.6g/t gold and the 400,000oz Wilsons Underground sulphide resource grading 4.31g/t gold.

Infill drilling is under way at Kingfisher to improve resource confidence, while existing underground development at Kingfisher, Swan, and Omega could lower the capital needed to access higher-grade material outside the current mine plan.

Horizon has also identified toll processing or a joint venture as possible lower-capital early production routes under existing approvals, although neither option forms part of the DFS production target.

“The completion of this DFS is a defining milestone for Horizon Gold, confirming Gum Creek as a robust, simple and technically de-risked development project ready to advance quickly toward a FID,” chief executive officer Scott Williamson said.

"Gum Creek is one of the most advanced undeveloped gold projects in WA, and this study underpins a clear pathway to production in 2028."