Our history

After confirmation of John Campbell Miles' mineral discovery, he promptly secured 40 acres around the original outcrops, that would evolve into a highly productive mine. He named one of the larger of the two outcrops 'Mount Isa'.

In January 1924, Mount Isa Mines Limited was established.

Despite the challenges posed by its remote location, the isolation fostered a profound sense of loyalty and camaraderie among Mount Isas's early settlers. Through thick and thin, the community stood united, whether in sickness or celebration, triumph or tragedy.

As Mount Isa Mines grew, the need for a thriving community and amenities became apparent to attract workers to the mine. The company purchased houses from Duchess to accommodate some employees, however most miners constructed their own dwellings, often opting for tents.

In the same year, Mount Isa underwent surveying, leading to the sale of 150 allotments at auction. Prices started at £50, which is more than A$14,000 today. With Mount Isa's population burgeoning, the scarcity of housing and basic services reached critical levels.

Despite community petitions for essential infrastructure such as schools and post offices, the Queensland Government hesitated to invest state funds, adopting a cautious 'wait and see' approach. In response, structures from the former mining town of Kuridala were relocated to Mount Isa, including a courthouse, school building and a hospital.

When land was made available for sale in the town, only two hotel licenses were granted, and two new pub buildings were erected, highlighting the additional accommodation and meals needed for the growing community.

Discover the rich history of Mount Isa and its resilient community, forged through the trials and triumphs of its early years.

Overcoming early challenges

The early years were marked by the arduous task of developing the silver-lead ore bodies, which entailed financing, diamond drilling, metallurgical testing, and shaft sinking. There were several diamond drilling programs to determine the full potential of John Campbell Miles' discovery. One of the drilling holes indicated the presence of copper.

A crucial infrastructure requirement was a reliable supply of water. An experimental dam was constructed to test the water holding capacity of the ground in Mount Isa. From these tests a large Dam was constructed by MIM on Rifle Creek which was completed early 1930 and overflowing the same year. A pipeline was laid from Rifle Creek to Mount Isa Mines plants and Power Station.

All the infrastructure required was built and completed between 1929 and 1931. These included landmarks such as Lawlor Shaft and Winding Plant, Urquhart Shaft and Headframe, Mount Isa Mines Power Station, and Mount Isa Mines Experimental Dam all of which remain heritage sites in the Queensland Heritage Register for Mining Infrastructure.

Mount Isa Mines encountered challenges in both mine development and ore transportation to the port in Townsville. To expedite progress on the crucial Mount Isa to Duchess railway line, Mount Isa Mines struck a deal with the State Government. This agreement pledged to cover any operating losses incurred during the railway's first decade, a commitment valued at an astounding £100,000.

Construction on the new Duchess to Mount Isa railway line commenced in April 1926. In April 1929, the inaugural train chugged into Mount Isa, heralding an efficient mode of transport for both workers and ore. The line was officially opened by the Queensland Attorney General, the Honourable John Mullan MP.

This railway quickly became the state's most lucrative, providing the government with capital to rejuvenate other rail lines across Queensland, underscoring its pivotal role in regional development.

Ore reserves

An article in the Northern Miner newspaper about the official opening of the Railway reported that; “Initial ore reserves were estimated at 21,200,000 tonnes, with the processing plant engineered to handle a nominal daily capacity of 1,500 tonnes, extendable to 2,000 tonnes per day. Anticipating success, provisions were made for a second unit to potentially double daily ore treatment to 4,000 tonnes."

It also said that forecasts suggested that maximum production on the first unit would be achieved by the close of 1930. The Chief Government Geologist of the era projected a conservative annual output of 1,600,000 tonnes, and the potential for a century of productivity.

Such predictions positioned the mine as one of the world's most substantial individual lead-silver deposits.

In 1931, the advent of lead-zinc mining ushered in a new era of mechanisation previously unseen in Australia. Mechanised drilling and mechanical shovels replaced traditional 'hammer and tap' hand drilling and hand shovels, revolutionising the mining process. Initial mine production peaked at 660,000 tonnes annually and remained relatively consistent until 1953.

Milling and smelting trial and setup operations commenced in Mount Isa in May 1931. Production commenced in June 1931, however operations encountered challenges and it took 13 years for the company to record its first operating profit, marking a significant milestone in its journey.

Impact of the Great Depression

Despite its eventual profitability, Mount Isa Mines faced significant challenges in its early years. The operation encountered industrial strife during its initial production period, including worker strikes and stop-work meetings. Additionally, the recovery of valuable minerals in the concentrator fell short of expectations, and metal prices were adversely affected by the Great Depression of the 1930s.

In late 1933, Julius Kruttschnitt, then General Manager, made the decision to temporarily close all operations due to an illegal strike, plummeting metal prices, and substantial financial losses. With no indication of when operations would restart, a mass exodus of workers followed. Hundreds of men boarded trains without tickets, confronting authorities at wayside stations along the 970-kilometre journey eastward to the coast. This episode, dubbed 'Strikers Jumping the Rattler,' culminated in a confrontation between miners and police near Townsville, resulting in multiple arrests.

During this period, more than 2,000 individuals, including men, women, and children, departed for the coast, leaving behind vacant cottages and shanties. However, in January 1934, the mine reopened after securing a loan from overseas investors. This development prompted a swift return of workers and mining activity.

While Mount Isa Mines faced numerous setbacks and challenges in its early years, it set the foundations for the resilient community, camaraderie and enduring spirit that thrives today.

Although traces of copper mineralization were identified during late 1920s drilling efforts, the significant discovery occurred in 1930. During exploratory drilling for the lead-zinc ore body, almost 38 metres of copper mineralization with an average grade of 4.3% copper was discovered.

Despite the promising grade, Mount Isa Mines lacked the financial means to develop the copper deposit. It wasn't until global copper prices rose in 1937 that renewed interest in copper exploration emerged. However, initial exploration efforts between 1937 and 1939 yielded little success.

It wasn't until 1940 and 1941 that significant progress was made in uncovering additional copper deposits.

Construction started in 1949 on a stack for the new copper smelter and extensions to the Mill/Concentrator to treat the copper ore.

During the early 1950s, the expansion of commodities drew a fresh wave of settlers to Mount Isa. Among them were post-war immigrants who viewed Mount Isa as a chance to rebuild their lives far from their war-torn European homelands.

Embodying the pioneering spirit necessary to seize opportunities within the burgeoning mining industry, these newcomers were embraced into Mount Isa's mining community. Their enduring influence is evident in the vibrant and culturally diverse fabric of Mount Isa today.

The new copper stream production construction projects required a massive number of workers.

In 1953, there was a significant milestone with the commencement of parallel production of copper, lead and zinc, further solidifying Mount Isa's position as a hub of mining and metal production excellence.

Critical housing solutions

With the copper and lead production, Mount Isa experienced a population surge, which intensified the demand for infrastructure and essential services within the town.

Responding to the critical need for housing, Mount Isa Mines embarked on an ambitious initiative, constructing homes for employees in Soldiers Hill, a time when housing availability was scarce, and many residents still lived in tents. In October 1953, the Mount Isa Mines Limited Co-operative Housing Society No. 1 was established to facilitate community-driven housing solutions.

By 1957, the escalating cost of housing finance posed a significant challenge for both employees and the company. To alleviate this burden, the Bank of New South Wales assumed responsibility for all mortgages, with Mount Isa Mines guaranteeing the loans and absorbing the variance in interest rates, ensuring no additional cost to the community.

By 1958, nine housing societies were operational, providing home-building finance for over 500 families.

Between 1952 and 1958, Mount Isa Mines supported over 600 employees in enhancing their homes through material assistance programs.

Subsequently, Mount Isa Mines facilitated the sale of 197 homes to employees previously occupied on a rental basis through the Mount Isa Mines Limited Home Purchase Co-operative Society Limited.

In 1967, despite escalating property prices, sale prices were based on depreciated valuations, enabling more than 170 homes to be financed. In collaboration with the Queensland Housing Commission and the Mount Isa City Council plans were set in motion to construct an additional 100 homes, culminating in the creation of the modern Sunset suburb.

Recognising the diverse housing needs within the community, Mount Isa Mines initiated the construction of an additional 100 modern, self-contained flats in Parkside, catering to individuals and families not yet ready for home ownership. Equipped with centralised laundry facilities and individual air conditioning units, these flats provided affordable rental accommodation close to the company's mining developments.

Continued expansion and new reserves

By 1955, Mount Isa Mines had emerged as Australia's largest mining company, overcoming technical, financial, and industrial challenges to become the nation's leading exporter. In 1958, the company further solidified its commitment to community well-being by securing a robust water supply through the construction of Lake Moondarra, the largest water scheme in Australia financed by private enterprise.

Amidst expanding ore reserves, Mount Isa Mines recognised the strategic advantage of establishing an electrolytic refinery to produce copper cathode for domestic and international markets. Townsville was chosen as the refinery site due to its port facilities, offering direct access to overseas customers and efficient transportation networks for domestic distribution. The copper refinery commenced operations in July 1959, with a capacity of 40,000 tonnes, heralding a new era of production that continues to operate today, with nearly 300,000 tonnes of saleable copper cathode produced annually.

In March 1957, the Black Rock open cut commenced operations, extracting copper oxide ore utilised as a flux in the copper smelter until 1963. Premature closure of the Black Rock open cut ensued in 1965 due to instability in its western wall.

In a strategic move in March 1966, Mount Isa Mines consolidated its mining lease holdings by acquiring all territory between Hilton, and the Mount Isa operations under a single Special Mining Lease.

Simultaneously, lead-zinc ore processing transitioned to a new concentrator, designated as the No. 2 concentrator, employing a milling and flotation process. This period also witnessed significant modernisation of the lead smelter and the commissioning of a new shaft, initially referred to as the K57 shaft, later renamed R62 to comply with metric grid pattern location. The lead ore haulage system was revamped to transport ore to the new No. 2 concentrator using this shaft.

Between 1969 and 1974, substantial advancements were made in the development of copper ore bodies and enhancements at the company's Townsville refinery, resulting in a remarkable upsurge in copper production. Subsequent years saw the implementation of numerous on-site technological innovations, driving advancements in metallurgical processes.

During the 1970s, Mount Isa Mines experienced remarkable growth, innovation, and consolidation, establishing itself as a prominent mining entity in Australia. Mount Isa boasted a vibrant and diverse population, characterised by significant migrant and Indigenous communities. In the post-war period, against the backdrop of rising lead prices and expanding ore production in Mount Isa, numerous immigrants ventured across the arid plains to seek better wages and the promise of a fresh start in Australia.

A time of multiculturalism

Throughout this time, 52 different nationalities were represented in Mount Isa including Irish, Italians, Scottish, Greeks, Sicilians, Germans, Hungarians, Yugoslavians and Serbians (to name a few). However, one of the most populous cultures in our rich history included the Finnish nationals, who helped build Mount Isa Mines and the Mount Isa community from the beginning.

A time of expansion

Mount Isa's population surged from approximately 8,000 in the 1950s to 25,000 in the 1970s.

This population expansion was largely fueled by a substantial influx of immigrants drawn to Mount Isa Mines by the relatively high wages offered. Notably, around 1,500 Finnish nationals migrated to the area, earning admiration for their strong work ethic.

In 1973, Mount Isa Mines inaugurated the No. 4 Concentrator, a state-of-the-art facility designed to process copper ore, leading to the closure of the old No. 1 Concentrator. This initiative markedly augmented blister copper production at the time.

Mount Isa thrived during this period, with its newest residents gaining renown not only for their industriousness but also for their penchant for revelry. The town witnessed the emergence of various social clubs, including the Finnish Club, Irish Club, Concordia Club (German Club), Caledonian Club (Scottish Hall), and Italian Club, which became bustling hubs of activity on weekends.

A time of “mateship”

Sports thrived in Mount Isa, with fields and ovals bustling with activities ranging from football, soccer, basketball, softball, to cricket, depending on the season. These weekend sporting traditions played a pivotal role in fostering a sense of family and camaraderie within the burgeoning community.

In 1974, with the support of Mount Isa Mines, the city inaugurated the Mount Isa Civic Centre, providing a central venue for cultural and community events. Additionally, in 1976, Lake Julius Dam was constructed on the Leichhardt River, situated 100 kilometres north of Mount Isa, ensuring a reliable water supply to meet the city's growing demands.

Construction began in 1977 on an imposing stack for Mount Isa Mines' Lead Smelter operations. Completed in 1978, this monumental structure is 270 metres tall and boasts a base diameter of 22 metres, towering over the city skyline. Designed to replace the previous stack, which measured only 76 metres in height, the new structure (which still stands today) significantly mitigates the impact of smelter emissions on the surrounding community.

A time of innovation

The 1970s were pivotal in shaping the trajectory of Mount Isa Mines and fostering a community renowned for its diversity and welcoming atmosphere.

During the construction of the new Lead Stack, Mount Isa Mines' copper refining subsidiary pioneered the Isa Process copper refining technology. Today, this innovative process is utilised by over 100 refining operations worldwide and is widely recognized as the preferred method for copper refining.

During this period, Mount Isa Mines collaborated with the Commonwealth Scientific and Industrial Research Organisation (CSIRO) of the Australian Government to develop the energy-efficient ISASMELT™ smelting technology.

Following laboratory trials of a potential lead smelting method at CSIRO's Melbourne facility, Mount Isa Mines progressed to a 120-kilogram per hour test rig at our Lead Smelter in 1980, and subsequently to a five-tonne per hour pilot plant in 1983. This journey culminated in the development of a copper smelting process, leading to the establishment of a 15-tonne per hour copper ISASMELT™ demonstration plant in the Copper Smelter in 1987.

Integral to the success of the ISASMELT™ technology was the active involvement of our plant operators during its development. Their input ensured the technology's practicality, resilience, and widespread adoption by other operations.

In the realm of copper mining, the Deep Copper Mine project was underway, with a significant ore body located near the R62 shaft. To facilitate the haulage of ore and muck from this site, a fleet of electric trucks was deployed. These trucks drew power from 1,000-volt overhead busbars and utilized batteries built into the vehicles where overhead power was unavailable. Each truck boasted a hauling capacity of 50 tonnes up a 1-in-10 incline.

Moreover, all process control systems within the plant, including the power stations, underwent an upgrade to the Yokogawa μXL Distributed Control System. This state-of-the-art computer-controlled system featured data logging and informative graphics, enhancing operational efficiency and precision across the board.

Pioneering technology

For a period in 1980, Mount Isa Mines was Australia’s largest company, having pioneered several significant mining industry innovations which have been widely adopted around the world.

These included the ISASMELT™ smelting technology, the IsaMill™ fine grinding technology, and the commercialisation of the Jameson Cell flotation technology.

Jameson Cell

In 1985, Mount Isa Mines sought the expertise of Professor Graeme Jameson from the University of Newcastle to enhance the performance of flotation columns utilised in the Zinc-Lead Concentrator's recovery process. Professor Jameson introduced a groundbreaking concept: the intense mixing of air and concentrate slurry in a specially designed pipe, now known as the downcomer, inserted into the flotation column.

This innovation resulted in the generation of finer bubbles, crucial for the recovery of fine minerals present in Mount Isa's ore, along with enhanced operational robustness and reduced equipment size compared to traditional flotation columns. Thus, the Jameson Cell was born. Professor Jameson patented the cell in 1986, and a two-tonne per hour pilot cell underwent testing in Mount Isa.

In 1988, Mount Isa Mines opted to enhance the capacity of its Heavy Medium Plant slimes flotation circuit to bolster lead recovery. After exploring various alternatives, two full-scale Jameson Cells were installed in the Zinc-Lead Concentrator in 1989.

In April 1989, MIM secured the international rights to the metallurgical applications of the Jameson Cell, initiating its marketing while continuing to refine the technology. By 2013, over 320 Jameson Cells were in operation globally across coal and base and precious metal flotation circuits, as well as industrial minerals, oil sands, and SX-EW applications.

By the 1990s, MIM had emerged as a pioneer in innovative mining techniques and cutting-edge processing technologies.  A significant milestone occurred in 1978 when Copper Refineries Limited (CRL) introduced the ISA PROCESS™ copper refining technology, which has since garnered global acclaim, with over 100 licensees worldwide utilizing the technology.

In 1990, Mount Isa Mines constructed a solvent extraction electrowinning (SX-EW) facility aimed at extracting copper from low-grade ore accumulated from the Black Rock open cut. This innovative process involves using liquids to leach copper from crushed ore, with the extracted copper then recovered from the leached liquid through the application of electric current. The result is the production of copper cathodes with a purity level of 99.995%.

At the same time, an experimental cobalt extraction plant was constructed to extract cobalt from the tailings.

ISASMELT™

In 1992, MIM introduced an ISASMELT™ furnace to replace one of the two reverberatory furnaces in the Copper Smelter, capable of processing 104 tonnes per hour of concentrate and yielding 180,000 tonnes of copper annually.

Initially, throughput was constrained by interactions with the remaining reverberatory furnace. However, this issue was resolved in 1997 through the closure of the fluidised bed roaster and the remaining reverberatory furnace, alongside the addition of a fourth Peirce-Smith converter and a second oxygen plant. Consequently, the ISASMELT™ furnace's throughput surged to over 160 tonnes per hour of concentrate.

Since then, the ISASMELT™ technology, renowned for its simplicity, flexibility, and efficiency, has been widely embraced by operations globally. Presently, 15 ISASMELT™ plants operate across 10 countries, with numerous others licensed and in the design phase. These facilities process a diverse range of minerals and materials, including copper concentrate, lead concentrate, and scrap feeds, collectively smelting nearly 12 million tonnes of material annually.

IsaMill™

The focus shifted to improving the grinding process next. This became crucial by the mid-1980s when metal recoveries from the Zinc-Lead Concentrator started declining due to the increasingly fine grain size of the ore. A method for finer ore grinding was necessary to effectively separate the lead and zinc mineral particles from each other and from waste material.

After conducting a global search for suitable technology, Mount Isa Mines embarked on a joint development program with the German company Netzsch-Feinmahltechnik GmbH. This collaboration resulted in the creation of the IsaMill™, a highly energy-efficient horizontal stirred mill.

In addition to its enhanced efficiency, IsaMills utilize inert grinding mediums such as ceramic balls, smelter slag, or silica sand. These mediums ensure clean mineral surfaces, optimising the subsequent flotation process and further improving mineral recovery. Following successful testing of prototypes at various scales, the first full-scale IsaMill™ was installed at the Mount Isa Zinc-Lead Concentrator in 1994, with additional installations at Mount Isa and the McArthur River Mine in the Northern Territory in 1995.

MIM commenced licensing the technology in 1999.

An enduring legacy of innovation

Nearly two decades later, over 120 mills have been installed in concentrators worldwide, spanning various applications including zinc, lead, precious metals, iron ore, PGMs, industrial minerals, copper, and molybdenum. Moreover, the technology has undergone significant evolution, transitioning from ultra-fine to coarser regrind applications.

Today, Glencore's Technology subsidiary, XT, continues to promote and provide support for the ISA PROCESS™ (now known as IsaKIDD™), ISASMELT™, IsaMill™, and the Jameson Cell across the globe. Additionally, they are actively involved in the development and marketing of other cutting-edge products such as the Albion Process™, HyperSparges™, and ZipaTanks™, catering to the diverse needs of the global mineral processing, metals smelting, and refining industries.

2000–2007: A transformative chapter

The years spanning from 2000 to 2008 witnessed a transformative chapter in the history of Mount Isa Mines.

In 2000, production began at the George Fisher Mine and further freehold lots were purchased by MIM to expand and develop the greenbelt zone to increase the buffer between the mine site and the city of Mount Isa. Environmental monitoring efforts were intensified, including the conversion and calibration of PM10 samplers and the installation of new fall-out gauges for dust deposition, contributing to the national pollution index.

Noteworthy engineering projects unfolded during this period, such as constructing a cover on tailings dam 5 and the decommissioning of the George Fisher evaporation pond. The commitment to environmental responsibility included the relocation of dust deposition samplers and the establishment of an airborne emissions working group to address fugitive emissions from smelters and stockpiles.

In 2003, Xstrata acquired Mount Isa Mines. The operations were subsequently split into distinct streams for copper and zinc, leading to the commencement of the Black Star Open Cut zinc-lead mine in 2004 and the closure of the lead mine in December 2005. The implementation of advanced monitoring systems, including Tapered Element Oscillating Microbalances (TEOMs), showcased a commitment to reducing dust emissions.

Environmental management efforts continued with the development of a real-time decision support system and the upgrade of tailings dams 7 and 8. The following years saw comprehensive studies on flora, fauna, community health, and personal exposure to measure the impact of mining activities on the environment and the local population.

The issue gained prominence 2006, leading to the controlled collapse of the Fluoro Solids Roaster plant and the commissioning of the independent Lead Pathways Study. Initiatives such as the Xstrata Skills Centre, the Living with Lead Alliance, and the establishment of a hygiene department for the Lead Smelter reflected a commitment to addressing community concerns.

The latter part of the period witnessed substantial upgrades in emissions control, stormwater containment facilities, and the introduction of daily planning processes to reduce emissions. The construction of the Xstrata Power Station and the implementation of the Get Bled for Lead screening program by Queensland Health in December 2007 underscored ongoing efforts to monitor and mitigate the environmental and health impacts of mining activities in Mount Isa.

2008–2015: Environmental responsibility, community engagement, and operational improvements

The period from 2008 to 2015 reflects a multifaceted approach towards environmental responsibility, community engagement, and operational improvements.

2008:

• Commenced operations at the zinc clean-in clean out facility to boost operational efficiency.
• Launched the MICO New Starters program and 'Xstrata and you building a healthier future' initiative, focusing on workforce well-being.
• Successfully completed the Leichhardt River Remediation Project, involving significant material removal and clean rock placement to mitigate environmental impacts.
• Initiated a mine tailings study in collaboration with the University of Queensland's Centre for Mine Land Rehabilitation, underscoring commitment to responsible waste management.

2009:

• Conducted a comprehensive biodiversity assessment.
• Completed construction of the Northern Gate Laundry facility to enhance employee well-being.
• Introduced the Employee Lead and Arsenic Guide and established purpose-built blood sampling centres to prioritise health and safety.
• Implemented the 'Get Bled for Lead' program to monitor lead levels in the community.

2011-2012:

• Unveiled a long-term vision for Mount Isa Mines, including plans for the closure of the Copper Smelter by 2016.
• Signed an Indigenous Land Use Agreement with the traditional owners, the Kalkadoon People.
• Secured approval for a $274 million expansion of Xstrata Zinc’s George Fisher Mine in October 2010.
• Recognised as Queensland Miner of the Year in 2012, with a focus on environmental responsibility highlighted by the Lead Smelter Fugitive Emissions Characterization Study.
• Completed the merger with Glencore in 2013, consolidating the company's position in the global mining landscape.

2014-2016:

• Carried out environmental studies on the health of Mount Isa Waterway and Air as part of the Lead Pathways Study, showcasing transparency and accountability.
• Undertook operational enhancements, including the Copper Smelter $30 million rebrick project in 2014 and the Environmental Authority amendment application for the Copper Smelter Extension Project in June 2015.
• Introduced the Indigenous Employment Program and completed the McNamara Road upgrade in December 2015.

2016–2024: A strategic shift

2016: The Black Star Open Cut transitioned to a state of care and maintenance; and the Girls for Mining mentoring program was launched, supporting diversity and young women considering a future in the resources industry.

2018: Another Copper Smelter rebrick project was completed, as part of the four year cycle to replace refractory bricks; and in collaboration with the Mount Isa City Council, the Black Rock Cave project commenced.

2019: The decommissioning of the George Fisher Mine/Handlebar Hill Open Cut camp; and the release of the independent study, Mount Isa Air.

2020: Mount Isa Mines contributes to A$725,000 for the development of a COVID-19 vaccine; and funding is announced by the Statement Government to assist the continued operation of the copper smelter and Townsville copper refinery.

2021: Underground mining contractor Pybar Mining Services was awarded the production contact to mine Black Rock Cave. Upgrades to the Mine Rescue facility and Lead Smelter, alongside a service support agreement with ABB Process Automation for mine hoists, further solidified our commitment to operational excellence.

2022: The exploration team conducted a groundbreaking 3D seismic survey, exploring possibilities for asset life extension.

2023: Glencore announced the planned closure of Mount Isa Copper Operations and copper concentrator in 2025, with a focus on its long-life zinc-lead-silver operations and copper smelter.

In 2024, Mount Isa Mines celebrates 100 years of operations. The '00’s period represents a chapter in the company's history characterised by dynamic responses to challenges and a forward-looking approach to sustainable mining practices.