Rovina Valley Case Study – Stormlands Mining

11 MAY 2026 – STORMLANDS MINING LTD

Stormlands Mining publishes Rovina Valley case study showing sensitivity to stronger gold and copper prices

Independent Stormlands model closely aligns with Updated Definitive Feasibility Study (Dec 2025) project valuation

Illustrative scenario shows how project economics may respond to March 2026 average commodity prices

Dublin, Ireland, 11 May 2026. Stormlands Mining has published a new independent case study on the Rovina Valley Project in Romania, information from the NI 43-101 (Updated Definitive Feasibility Study (DFS) effective date December 2025), and Stormlands’ proprietary mining valuation platform (see notes to editors).

The Rovina Valley analysis is one of the first in a planned series of case studies to be produced from the Stormlands Library, a new repository of mining asset valuation models and illustrative scenarios. The Library will contain illustrative scenarios to help users to understand the key drivers of mining asset valuations.

Stormlands’ base case aligns with the NI 43-101 (DFS Dec 2025) valuation. The DFS reports an after-tax project NPV of US$1.469 billion and an IRR of 35.6%, with the project breaking even on a cash basis approximately 2.6 years after the start of production. Stormlands’ base case, built from the NI 43-101 technical assumptions, produces a comparable post-tax project NPV of US$1.443 billion, a difference of less than 1%.

The case study then uses the Stormlands platform to examine how project valuation would respond to different assumptions. The most significant insight is the project’s sensitivity to stronger gold and copper prices. Using the NI 43-101 base case assumptions of US$3,300/oz gold and US$9,920/t copper, Rovina Valley shows a robust project-level valuation. In a separate illustrative scenario, Stormlands applies March 2026 average prices of US$4,877/oz gold and US$12,499/t copper. Under that scenario, modelled project NPV increases from approximately US$1.44 billion to US$2.82 billion, while IRR rises from approximately 31% to 50%.

The illustrative price scenario also materially improves key project metrics. Life-of-mine revenue increases from approximately US$6.4 billion to US$9.1 billion, while life-of-mine EBITDA rises from approximately US$3.7 billion to US$6.3 billion.

This is not merely an accounting uplift. In the Stormlands scenario, higher commodity prices materially change the modelled risk-reward profile. Payback improves from 37 months to 26 months, reducing the period of capital exposure. Net smelter return increases from approximately US$52/t ore to US$74/t ore, and operating margin improves meaningfully. Government also benefits: corporate income tax rises from about US$483 million to US$891 million, while government royalties increase from about US$385 million to US$548 million.

Stormlands’ sensitivity analysis identifies gold price as the dominant value driver for Rovina Valley. A 10% reduction in gold price reduces modelled NPV (based on DFS commodity prices) to approximately US$1.2 billion, while a 10% increase raises NPV to approximately US$1.7 billion. Copper price is also positive but less influential, with a 10% copper price increase lifting NPV to approximately US$1.5 billion. Operating cost is the second most important value driver, while treatment and refining charges have a smaller valuation impact.

“Rovina Valley is a useful example of why mining valuation needs to be dynamic,” said Róisín O’Connell, CEO and Co-Founder of Stormlands Mining. “A technical report provides the foundation, but investors and other stakeholders also need to understand how project economics change when value drivers change such as metal prices. The Stormlands Library is designed to make that type of analysis faster and easier to compare across projects. It makes valuation models accessible over any platform to all users, putting the data directly in the hand of the decision maker.”

The Rovina Valley case study is a clear example of Stormlands Mining’s broader ambition: to build a global repository of interactive valuation models for mining assets. By turning technical reports into dynamic, comparable models, Stormlands aims to make project economics easier to interrogate, helping users move beyond static disclosures and understand how value changes as market conditions, geology, costs evolve.

Notes

The Rovina valley base case model was based on the NI 43-101 Updated Technical Report on Rovina Valley Project in Romania – Updated Definitive Feasibility Study prepared for Euro Sun Mining Inc prepared by Adar Consulting Corp, effective date 23 December 2025.
Stormlands Mining illustrative scenario with updated Commodity Price uses commodity prices from March 2026:
Gold USD/oz 4,877.40 USD/Oz
Copper USD per ton 12,498.98 USD/ton

Stormlands Library: https://www.stormlandsmining.com/library/

Rovina Valley case study: https://www.stormlandsmining.com/library/library-rovina-valley/

Download PDF of case study: https://tinyurl.com/Rovina-Valley-case-study

Important notice

This publication is for informational, educational and illustrative purposes only. It is based on publicly available information, including the Rovina Valley NI 43-101 technical report and related public disclosures, together with independent modelling undertaken by Stormlands Mining.

The analysis is not a technical report, updated technical report, mineral resource estimate, mineral reserve estimate, valuation opinion, investment research report, securities recommendation, offer to sell, solicitation to buy, or investment advice. The March 2026 commodity-price case is an illustrative scenario only and should not be interpreted as company guidance or an updated valuation prepared by or for Euro Sun Mining Inc.

Stormlands Mining has not been engaged by Euro Sun Mining Inc. or its affiliates to prepare this analysis. This publication has not been reviewed, approved or endorsed by Euro Sun Mining Inc., its advisers, or any Qualified Person associated with the Rovina Valley Project. Stormlands Mining has not received material non-public information from Euro Sun Mining Inc. in connection with this analysis.

Model outputs are scenario-based and depend on assumptions, 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.