Mining giant BHP is buying a $50 million stake in copper-gold explorer SolGold, the majority owner of a project in Ecuador.

BHP has agreed to pay Canadian company Guyana Goldfields about 27.4 million pounds ($A49 million) for a 6.1 per cent interest in the London- and Toronto-listed company, which controls the ‘high quality’ Cascabel exploration project.

BHP chief executive Andrew Mackenzie said the investment was in a ‘highly prospective’ location, adding copper was a focus as the global miner seeks to replenish its resources base.