The stamp has a hidden date near the minor's foot.
The Sixth Commonwealth Mining and Metallurgical Congress convened on 8th September, 1957, at Vancouver, B.C. During this event of international significance, delegates travelled from Vancouver to Halifax to visit mining areas and metallurgical and related industrial plants. Miner working underground with a pneumatic drill. This design emphasizes the importance of mining in the nation's economy, and the issue pays tribute to the progress in Canadian mining and to the employees in the entire industry.