The Remarkable and turbulent history of Hilton and George Fisher Mine
This year marks the 50 year anniversary of the sinking of the Hilton Shaft, the 30 year anniversary of the official opening of the Hilton Mine and 20 years of operation at the George Fisher Mine.
The Hilton zinc-lead-silver ore bodies, located 20 kilometres north of Mount Isa, were discovered in 1947 by Mount Isa Mines geologist Sydney Carter, 23 years after the discovery of high-grade lead carbonate by John Campbell Miles in Mount Isa.
It would be many years before the fruits of this discovery would be realised. From 1948 until 1957, a significant drilling program was undertaken and by 1950 Hilton ore reserves were proven at 26 million tonnes. However, the drilling program was curtailed in 1957 due to a fall in metal prices and heavy capital expenditure in the existing operations.
Later drilling intersected ore between 500 to 900 metres below the surface which provided the evidence that not only was the orebody continuous at depth, but that it was also of high grades in silver, lead and zinc. By 1968, the reserves were estimated at 35 million tonnes at 180g/t silver, 7.7% lead and 9.6% zinc, just as metal prices were increasing.
50 years since the sinking of the Hilton Shaft
In 1969, Mount Isa Mines proceeded with the Hilton Mine and the sinking of an exploration shaft (known as J53) began in June 1970 and was completed to a depth of 630 metres in June 1973. Sinking the P49 service and hoisting shaft, which is still in use today, began in 1971, and this shaft was completed to a depth of 1,040 metres in December 1975.
A twin P48 shaft was also planned to mirror the F58 and K57 shafts at the main mine in Mount Isa and a township on the Eastern side of the Barkly Highway was even planned to service the mine but these was never built.
After the completion of the P49 shaft and permanent headframe, the project was suspended for several years due to market factors and capital being diverted to the construction of the Lake Julius dam wall, the 270 metre high lead stack and construction of the heavy medium plant before it resumed again in the 1980s.
30 years since the official opening of Hilton Mine
After 40 years of on and off development, Hilton finally began production in 1989 with the official opening held on 15 May 1990. It was originally named in honour of Charlie Hilton, the General Manager of Mount Isa Mines at the time of discovery.
The event attracted a crowd of over 300 people and was set on a plateau overlooking the headframe to signify the transition from development to production at Hilton.
Mount Isa Mines chartered an airliner to bring a plethora of dignitaries including the Premier's party, the Minister for Resource Industries, former Directors of the Mount Isa Mines Board Union, Opposition spokespersons on Resource Industries, ex-Hilton employees and Mount Isa Mines staff from Brisbane.
Notably amongst those were Sir George Fisher, former Chairman of Mount Isa Mines whose commitment to Hilton's development in 1969 proved to be one of the milestones in the mines progress.
The ceremony was highlighted by the presence of then Queensland Premier Wayne Goss who addressed the audience on the importance of Hilton to Queensland and Australia before unveiling the plaque commemorating the opening of the mine.
Read the full story of the Hilton Mine opening in the original MIMag article here.
20 years of George Fisher Mine
By 1998, most of the easily accessible ore at Hilton had been mined and production was slowed in favour of development of Hilton North, a similar mineralisation that was discovered two kilometres further North in 1981.
Renamed the George Fisher Mine, after former Chairman of Mount Isa Mines − Sir George Fisher, the mine was officially opened in 2000. While cut-and-fill mining was originally used at Hilton mine, bench mining and open-stoping were later adopted at George Fisher Mine.
A feasibility project was conducted from 2009 to 2014 installing a new materials handling system and opening up a new mining block down to 1,160 metres at the Northern end of the George Fisher orebody with the capacity to increase production to 4.5 million tonnes of ore per annum.
The mine now forms part of Glencore's Mount Isa Mines, an iconic mining operation with a legacy of over 95 years. Today George Fisher Mine is one of the largest and most complex underground zinc, lead and silver operations in Australia.