Stormlands Mining publishes independent Whistler Gold-Copper Project case study showing major leverage to current gold and copper prices Illustrative scenario shows how project economics respond to March 2026 average commodity prices

Dublin, Ireland — 18 May 2026 — Stormlands Mining has published a new independent case study on the Whistler Gold-Copper Project in Alaska, using its AI-first mining valuation platform to model the project economics from publicly available technical information.

Stormlands independent modelling using March 2026 commodity prices for gold, copper, and silver as an illustrative scenario, shows that project Net Present Value (NPV) more than doubles in this scenario from US$2bn (base case) to US$4.71bn, while IRR rises from 32% to 61% and payback improves from around 30 months to 19 months. Life-of-mine (LOM) revenue increases from US$10.9 billion to US$16.1 billion, while LOM EBITDA rises from US$5.9 billion to US$11.0 billion. Estimated corporate income tax also increases materially, from approximately US$1.03 billion to US$2.18 billion.

This price scenario uses copper at US$12,498.98/t, gold at US$4,877.40/oz, and silver at US$74.92/oz, compared with the base case assumptions used in the NI 43-101 of copper at US$9,920.79/t, gold at US$3,200/oz, and silver at US$37.50/oz.

The Whistler case study is the latest release from the Stormlands Library, a growing repository of interactive mining asset valuation models designed to help users to understand the key drivers of mining project economics.

The base case analysis is based on the NI 43-101 Technical Report and Preliminary Economic Assessment dated March 2026, together with independent modelling by Stormlands Mining.

Stormlands’ base case model, using the technical-report and PEA assumptions, produces a post-tax project NPV of approximately US$2.02 billion at a 5% discount rate, with an IRR of 32% and payback of around 30 months after the start of production.

The model shows that Whistler is highly sensitive to commodity-price assumptions, particularly gold and copper. A 10% reduction in the overall price factor reduces project NPV to approximately US$1.44 billion, while a 10% increase raises NPV to approximately US$2.59 billion.

Stormlands’ sensitivity analysis shows that gold and copper are the key external value drivers. A 10% increase in gold price lifts NPV to approximately US$2.16 billion, while a 10% increase in copper price lifts NPV to approximately US$2.12 billion. Operating cost and capital cost are also material drivers, with operating-cost discipline particularly important in protecting value under lower-price scenarios.

Stormlands’ heatmap analysis shows that Whistler remains meaningfully positive across a broad range of price and operating-cost scenarios, while stronger commodity prices and lower operating costs move the project into a materially higher-value range.

Phil O’Connell, Chief Product Officer of Stormlands Mining, said: “Whistler is a good example of why mining valuation needs to move beyond static PDF reporting. The base case already shows a substantial gold-copper development project, but the real insight comes from being able to test how value changes as assumptions move. Under stronger gold and copper prices, the Whistler model shows a very significant uplift in NPV, IRR, payback and government tax outcomes.”

The Whistler case study follows Stormlands’ earlier Rovina Valley Project analysis and forms part of the company’s plan to build a global library of mining asset valuation models. The Stormlands Library is intended to provide a structured source of mining project models, enabling users to screen assets, benchmark projects and test assumptions.

The full case study is available through the Stormlands Library at https://www.stormlandsmining.com/library/whistler/

The analysis is based on the NI 43-101 Technical Report and Preliminary Economic Assessment dated March 2026, together with independent modelling by Stormlands Mining.

Stormlands Mining illustrative scenario with updated Commodity Price uses commodity prices from March 2026:

Gold:  4,877.40 USD/Oz
Copper: 12,498.98 USD/ton
Stormlands Library: https://www.stormlandsmining.com/library/
Whistler Gold-Copper case study: https://www.stormlandsmining.com/library/whistler/
Download PDF of case study: https://tinyurl.com/Whistler-Gold-Copper-Project

This publication has been prepared by Stormlands Mining Ltd. for informational, educational and illustrative purposes only. It is based on publicly available information, including the NI 43-101 Technical Report and Preliminary Economic Assessment March 2026, together with independent modelling undertaken by Stormlands Mining. Stormlands Mining has not been engaged by US Gold Mining Inc. or its affiliates to prepare this analysis. This publication has not been reviewed, approved or endorsed by US Gold Mining Inc., its advisers, or any Qualified Person associated with the Project. The analysis presented is not a technical report, mineral resource estimate, mineral reserve estimate, valuation opinion, fairness opinion, investment research report, securities recommendation, offer to sell, solicitation to buy, or investment advice. Stormlands Mining is not acting as a broker, dealer, investment adviser, corporate finance adviser, Qualified Person, or securities research provider in connection with this publication. All model outputs are scenario-based and depend on the assumptions used, including commodity prices, exchange rates, discount rates, capital costs, operating costs, taxes, royalties, production schedules, payability, recoveries, treatment and refining charges, timing assumptions and other inputs. Actual results may differ materially from the scenarios presented. Commodity prices, costs, financing conditions, permitting timelines and project development outcomes are uncertain and subject to change. Stormlands Mining does not represent or warrant that the information or model outputs are complete, accurate or suitable for any particular purpose. Readers should treat this publication as one source of information only and should conduct their own independent technical, financial, legal, tax and investment due diligence before making any decision. Neither Stormlands Mining nor any of its directors, officers, employees or advisers accepts any liability for any loss arising from reliance on this publication or the information contained in it.