A lone prospector, John Campbell Miles, stumbled upon one of the world's richest deposits of copper, silver and zinc during his 1923 expedition into the Northern Territory. When Miles inspected the yellow-black rocks in a nearby outcrop, they reminded him of the ore found in the Broken Hill mine that he had once worked at. Upon inspection these rocks were weighty and heavily mineralised. A sample sent away to the assayer in Cloncurry confirmed their value. Miles and four farmers staked out the first claims in the area. Taken with friend's stories of the Mount Ida gold mines in Western Australia, Miles decided upon Mount Isa as the name for his new claim.