In 2006 Sherry Dunsworth was consulting on the Valentine Lake project in western Newfoundland for Mountain Lake Resources when she happened upon some racks of drill core that had never been sampled. When she took a closer look, the structural geologist discovered the core was streaked with extensional veining and visible gold.

“That really stuck in my head,” said Dunsworth, who recognized quartz-tourmaline veins similar to those that characterize the gold deposits of the Abitibi belt in central Canada.

Today she is senior vice-president of exploration for Marathon Gold, which now owns 100 per cent of the 240-square-kilometre project after purchasing Mountain Lake in 2012. In May, the company issued a preliminary economic assessment that projects an 11-year mine life averaging production of 188,500 ounces per year at all-in sustaining costs of US$595 per ounce. Valentine Lake continues to yield high-grade intercepts along a 30-km gold-bearing shear zone.

Back in the 1970s, Dunsworth was pondering her future when she had the opportunity to sit down with the head of earth sciences at Saint Mary’s University in her hometown of Halifax. Attracted by the opportunity to work outdoors, she went on to complete a bachelor of science in geology at Saint Mary’s followed by a master’s degree specializing in structural geology at Memorial University in Newfoundland.

“I was the only female in the department at Saint Mary’s when I started, but it took me three months to realize that because I was so shy I just did my work.”

Dunsworth had been working as a geologist in the private and public sectors throughout Canada and in parts of Europe and South America for a couple of decades when she encountered the unsampled gold-bearing drill core that led her to develop the largest gold deposit in Eastern Canada.

Exploration got underway at Valentine Lake in 2010, a manageable drive from Dunsworth’s home in Pasadena, Newfoundland. She and her team went on to find four near-surface gold deposits that have all the markings of a future mine in a province Dunsworth considers a “privilege” to work in.