The company is listed on Canada’s TSX-V market and owns gold exploration projects in Macedonia, Bulgaria and Serbia.
The WPP-owned agency was appointed by Euromax director of comms Karen Atchison, who joined the company last year.
Euromax is paying Buchanan a monthly retainer of £4,000, rising to £5,000 if it is listed on a London Stock Exchange market.
Buchanan worked with Atchison and the Euromax management team when they were at another gold miner, European Goldfields, with which it had an eight-year relationship.
The account will be led by Buchanan’s senior partner Bobby Morse and account director Cornelia Browne.