Horizon Minerals Ltd (ASX:HRZ) has lifted its consolidated gold Mineral Resource after re-reporting multiple deposits at a lower cut-off grade, effectively pulling more lower-grade mineralisation into the reported inventory as the gold price environment improves project economics.
The company’s updated group position is 34.32Mt at 1.7g/t Au for 1.88Moz, underpinned by its larger cornerstone assets at Boorara and Burbanks. While the overall grade fell due to the inclusion of more lower-grade material, Horizon is framing the update as an “ounces-first” outcome that expands optionality as it advances studies around its broader Kalgoorlie and Coolgardie footprint.
The key lever behind the upgrade was a reduction in the reporting cut-off to 0.5g/t gold from 0.8g/t, a shift Horizon attributes to stronger bullion prices and work streams linked to mine planning and the upcoming Black Swan feasibility study.
On Horizon’s numbers, the update equates to a 16% increase in tonnes, an 8% decrease in grade, and a 6.5% (114,000oz) increase in contained gold compared with the prior global Mineral Resource statement. In other words, the company has accepted lower average grade in exchange for a larger overall inventory—an increasingly common trade-off in higher gold price cycles where marginal material can become economically relevant.
Boorara MRE 1/07/2021 – Depleted for Mining to EOM June 2025 – 0.5 g/t Au reporting cutoff.
“The sustained uplift in the gold price has brought previously marginal lower-grade tonnages into the economic envelope. By redefining cut-off grades, we have delivered a meaningful uplift in total resource ounces,” managing director and CEO Grant Haywood said.
Historical Gold Price (https://goldprice.org/gold-price-history.html).
“This positions the company with a more robust platform for future development, with the increased inventory to be incorporated directly into the Black Swan study planned for release in this current March 2026 quarter.”
Horizon Gold Projects.
Coote emerges as the standout gainer
The most dramatic change came at Coote, where Horizon said there is a substantial volume of mineralised material sitting between 0.5g/t and 1.0g/t. Re-reporting the 2022 model at the new cut-off produced a step-change outcome, delivering a 5-fold increase in tonnes and a 300% jump in ounces.
That kind of response underscores the deposit’s sensitivity to reporting assumptions rather than a sudden geological breakthrough — however, it still matters commercially. A larger resource base at Coote can broaden the range of potential mining and blending scenarios, particularly if Horizon is evaluating regional ore feed options and sequencing choices for future processing.
Golden Ridge North also responds strongly to the new threshold
A similarly cut-off-sensitive result was seen at Golden Ridge North, where re-reporting delivered a 230% increase in tonnes and a 41% lift in ounces.
While the percentage increase in ounces was less explosive than Coote, the tonnage expansion is notable because it can support different mining approaches and can potentially improve the robustness of future pit shells, particularly if the mineralisation is later shown to be continuous and accessible at scale.
Incremental gains across several other deposits
Horizon also re-reported Crake, Kalpini, Jacques-Peyes and Gordons Dam at the 0.5g/t cut-off, producing smaller but still meaningful additions that collectively contribute to the group uplift.
- Crake recorded a 28% increase in tonnes and a 12% lift in ounces, suggesting a meaningful halo of mineralisation that sits just below the previous reporting threshold.
- Kalpini delivered an additional 9,000oz (around 6%), a modest but useful lift that adds flexibility at a portfolio level.
- Jacques-Peyes increased tonnes by 6% and ounces by 2%, indicating a smaller sensitivity to the cut-off change.
- Gordons Dam moved from 20,000oz to 28,000oz, with tonnage rising from 365kt to 693kt, highlighting how lower-grade material can materially change the headline resource in smaller deposits.
Collectively, these outcomes reinforce Horizon’s central message: the resource base contains meaningful mineralisation in the “near-marginal” grade range, and the gold price backdrop is allowing the company to bring more of it into its formal inventory.
Depletion tempers the net increase
Offsetting some of the uplift, Horizon also accounted for depletion from mining at Boorara and Phillips Find through to June 30, 2025. At Boorara, the company reported the post-depletion resource at 9.79Mt for 398koz.
This is an important qualifier for investors: while the group resource has increased overall, parts of the portfolio are being actively mined down. The net change therefore, reflects both “inventory growth” through re-reporting and “inventory drawdown” through production.
Why it matters: more ounces for study work and optionality
Horizon is positioning the larger consolidated resource as an input into ongoing technical work, particularly the Black Swan feasibility study, which it is targeting for release in the March 2026 quarter. A bigger resource base can support longer-life mine plans, more flexible scheduling, and a wider set of economic trade-offs in the study work — especially where processing options, haulage distances, blending, and cut-off strategies are being tested.
In practical terms, the update doesn’t necessarily mean Horizon has discovered more gold in the ground; rather, it has redefined what it considers reportable in a higher price environment. But the commercial impact can still be significant: a larger reported resource can improve development pathways, strengthen funding narratives, and give the company more levers to pull as it refines the economics of its asset portfolio.