A defining period is approaching for mineral exploration companies in Western Australia’s Bryah Basin, the location of Sandfire Resources ’ ­attention-grabbing DeGrussa copper discovery.

Alchemy Resources , which owns tenements in the Bryah to the west of Sandfire, started drilling on its ground last week, while Talisman Mining, which owns tenements to the east, and Sandfire itself, are due to begin their own exploration programs shortly.