The ATO Gold Mine is a multi-phase precious metals project fully owned by Steppe Gold Ltd, covering a single mining license over 5,492.63 hectares. Open pit mining operations commenced in 2020, initially focusing on near-surface oxide ores.

Phase I – Heap Leach (Oxide Ore)

The oxide portion of the ATO Project is processed through a conventional oxide heap leach flowsheet that includes crushing, heap leaching, and gold recovery facilities.

Phase I established a fully integrated heap leach operation with complete site infrastructure and produced 128Koz of gold and 265Koz of silver from 2020 through October 2025.

Phase II – Concentrator (Fresh and Transition ores)

ATO Phase 2 Expansion is progressing with turnkey engineering, procurement and construction contract and consulting partners, focusing on boosting annual capacity and recoveries. This is expected to raise throughput and efficiency but may shorten mine’s lifespan. A revised feasibility study is underway, following the November 2025 Board decision to increase throughput to 3.3 Mtpa and the adopt a zinc-flotation tailings process.

Per the 2022 Mineral Resources and Reserves Report (NI 43-101) of ATO, the Project is outlined to consist of collecting the crushed ore beneath the ore storage building, conveying to the concentrator, milling, flotation, and dewatering unit operations to produce saleable concentrates of lead, zinc, and pyrite. Tailings will be disposed of at the new Tailings Storage Facility, a component that is not included in the existing engineering and construction scope.

Development timelines are dependent on the receipt of remaining site and infrastructure permits, associated assessment work, the completion of the revised feasibility study and the satisfactory resolution of Phase II financing.