John Campbell Miles (1883 – 1965) was the prospector and pastoral worker who discovered the mineralisation upon which the famous Mt Isa Mine was established in Queensland.
John Campbell Miles was born on 5 May 1883 in Melbourne. He was a wanderer and an adventurer from the time he ran away from school to work with a bootmaker. Blainey listed his quick progression of jobs as ploughman, miner, carter, railway navvy, wild-pig hunter and windmill repairer.
At the age of twenty-four (1907) he took a job as underground worker at Broken Hill, but stayed only until the following April before riding his bicycle 1,500 miles to the Oaks goldfield in north Queensland. While Miles would return to labouring work within a few months, his inauspicious prospect at the Oaks led to his discovery of the greatest twentieth century Australian mine.
From the Oaks, Miles worked as farm labourer in the Wimmera, then returned to Queensland where he spent ten years drifting from station to station, probably supplementing his wages by fossicking. After a brief visit to Melbourne in 1921, he decided to follow up the reminiscences of an elderly boundary rider who claimed to have seen gold on the Murranji Track, a cattle trail in the Northern Territory.