The news pushed the stock 7% higher Thursday as the achievement signalled the start of a 5,000t bulk sample that could be the first step towards the company's maiden gold bar being poured in about four years.
Osisko said the geology encountered in the ramp confirmed that predicted by drilling and the geological model.
The exploration ramp also encountered a mineralised section containing local visible gold in wireframe 101, immediately before achieving the targeted 115 wireframe bulk sample area.
Osisko said work off the exploration ramp over the coming weeks would focus on collecting the bulk sample, which would be transported to a custom milling facility in Ontario for processing in November.
Like most explorers, Osisko has seen its equity hammered by the strong US dollar, rising interest rates and alternative investment opportunities, causing a 35% drop in value over the past 12 months. The latest news lifted the stock C18c Thursday to $2.75, which gave the company a market value of about $689.56 million.