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.
He travelled slowly with his six horses, camping near to Hughenden and Richmond and visiting the ghost town of Mount Elliott on the Cloncurry copper field. Between Duchess and Camooweal he first met William Simpson of the Native Bee mine, who later became his partner. By this time it was February 1923 and he had been travelling for over a year.
Miles’ next camp was on the Leichhardt River where he prospected a low range of hills which yielded dark, mineralised samples. Following the trail of galena he arrived at the stumpy pyramid of banded ore that contained the Black Star lode. During this initial fossick, Miles discovered the rich central lodes of what would become the Mount Isa mineral field: the Black Star, Racecourse and the Rio Grande. Neither he nor the copper gougers he consulted could identify the stone, so they turned to Jim Tregenza, the Government Assayer in Cloncurry. On 23 February 1923, Tregenza assayed the samples as containing between 49.3 and 78.2 per cent lead, with silver content up to seventy-one ounces per ton.
With Bill Simpson and other Native Bee gougers, Miles robbed the Racecourse lode of nearly 18 tons of ore which they sold in Cloncurry to the ore-buying firm of Lempriere, calling the new field Mount Isa. The miners then pegged their leases: Miles and Simpson took up forty-two acres, including the Racecourse and the Black Star, to the north; Davidson, Roberts and Mullavey pegged the five acres of the Rio Grande. A small number of copper gougers pegged most other noticeable outcrops.
The selected ore sold in the field’s first year averaged sixty-four per cent lead and fifty-five ounces of silver, but the field was too isolated to attract capital or machinery until a report from the Cloncurry Mining Warden persuaded the Queensland government to act. It dispatched one of its geologists, E.C.Saint-Smith, who inspected the field and informed his employers that Mount Isa was perhaps the Commonwealth’s most important mineral discovery of the decade.
Saint-Smith’s report inspired a rush of prospectors to the field late in 1923. Among the new arrivals was Mount Elliott veteran, William Corbould who, in January 1924, floated Mount Isa Mines Limited. Simpson and Miles each received 500 shares worth nearly £a330,000. Simpson celebrated by catching a taxi from Duchess to Melbourne; a few days after his arrival he was run over and killed.
Miles continued to prospect in the area for another year, in the course of which he uncovered the fossils that allowed Saint-Smith to define the geological age of the field. He maintained his wandering life, gradually divesting himself of his shares at depressed prices; by 1933 he no longer had any financial interest in Mount Isa Mines.
Miles never married, indeed he claimed he had never witnessed a wedding. In 1957 Mount Isa Mines discovered his whereabouts and invited him to inspect his mine. The company supplied a small station wagon which he drove north from Melbourne, camping out on the way. He made his last visit to the field in 1962 when he informed his well-wishers that the secret of his good health lay in his avoidance of fresh fruit. He died in Melbourne on 4 December 1965 and was cremated. His ashes were taken to Mount Isa in 1968 and buried under a memorial clock tower in Miles Street.
Geoffrey Blainey, Mines in the Spinifex (Sydney, 1960); Australian Dictionary of Biography,Vol.10 (Melbourne, 1986).
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