The Chinese owner of the Tanco mine in eastern Manitoba has revived talk of partly draining a lake in order to extract more cesium from one of the world's few deposits of the critical mineral. Sinomine Resource Group is musing about a long-term redevelopment of the mine it purchased in 2019 along the shore of Bernic Lake, a small Canadian Shield body of water located between Whiteshell and Nopiming provincial parks. The goal is to reach cesium that cannot be mined right now, because it's embedded in vertical columns that hold up the roof of the underground mine.