Wonder is an underground mine, owned and operated by Northern Star Resources Limited (“Northern Star”) and is located in the Northeastern Goldfields of Western Australia, approximately 60 kilometers north of Leonora. Wonder is part of the larger Thunderbox Operations (TBO), approximately 25 kilometers south of the Thunderbox plant. TBO is located within Northern Star’s Yandal Production Center.

The Wonder underground mine is a supplementary source of high-grade underground ore feed for the Thunderbox Operations. A maiden underground resource was declared in May 2023, mining began in November 2023 and production stoping started in the third calendar quarter of 2024. The orebody is accessed by conventional jumbo lateral development with ore production coming from long-hole, open-stoping methods.