Brock Colterjohn

Brock Colterjohn is the President, CEO, and a director of Onyx Gold Corp. (TSXV: ONYX), a Canadian gold exploration company running a 110,000-metre drill program at its Munro-Croesus project near Timmins, Ontario. He is the executive investors hear on the company's program updates, and under his leadership Onyx Gold delivered the Argus Gold System discovery, a 641% share price gain in 2025, and a spot on the 2026 TSX Venture 50 — the TSX Venture Exchange's annual ranking of its top-performing listed companies.

He arrived at Onyx Gold with more than twelve years of experience spanning equity capital markets, mineral exploration, and production geology in Canada and Mexico. Colterjohn worked as a mining research analyst at Cormark Securities, covering junior precious metals exploration and development companies, and as a mining equity sales specialist at Canaccord Genuity, where he raised over $2 billion for corporate mining clients. Earlier in his career, he worked as an exploration and production geologist for AuRico Gold and other companies. He holds a B.Sc. in Geology from Dalhousie University and an MBA in Global Mining Management from the Schulich School of Business.

Colterjohn became President and CEO at Onyx Gold's July 2023 trading debut, leading a Discovery Group team spun out of HighGold Mining and backed by an initial C$8.4 million raise. His approach pairs geological training with capital-markets discipline: consolidate underexplored ground next to proven gold camps, drill systematically along structure, and finance with strategic investors. The company assembled roughly 335 km² of 100%-owned claims around the historic Croesus Mine, which produced at an average grade of 95.3 g/t (grams of gold per tonne of rock) from 1915 to 1936, and now controls about 16 km of the Argus Fault. Strategic financings in 2025 — including a brokered raise upsized to $18 million alongside non-brokered tranches at $2.43 per share — supported the buildout, and drilling expanded from 50,000 metres in late 2025 to 110,000 metres by April 2026.

Following Colterjohn offers a view of how a junior explorer turns drill metres into a system-scale discovery. Results through 2025 and 2026 included the high-grade Argus North zone — 2.4 g/t gold over 73.2 metres at depth in January 2026, and 2.3 g/t gold over 70.3 metres in a western expansion the next month — plus broad intercepts such as 1.7 g/t gold over 67 metres at Argus Main, and new drilling across the company's King Tut intrusion-related gold project in Yukon. His webinars and podcast interviews walk through what each round of results means for the size and significance of the emerging Argus system.