Lead Mining In Queensland: History And Processes - Mount Isa Mines

The mine does not have to be active at present. Your report should include most (if not all) of the following: 
Describe the mineral and how and where it was discovered (include maps) 
How did mining begin (and ended – if applicable) 
What impact did mining have on the local area e.g. physical, social, economic, environmental, etc.

Are there any environmental concerns? 
Where did the workforce come from?

What were their background? 
Did the mining have a real and lasting impact on the development of the area? 
Which company (or companies) operates (have operated) the mine? 
What mining methods were employed (and why)? 
Is the commodity exported? Where to? 
What is the use of the commodity? 
How has the demand varied over the years? Why? 
What is the forecast future demand for this product?

Lead

The Australian mining industry can be traced back to the gold rush of the 1850s and its one of the country’s most developed sectors, contributing to about 7% of the country’s GDP.  The mining sector is largely tailored for the export market, with most of the minerals exported in raw form for processing away from the country. Some of these minerals include gold, iron ore, lead, zinc, nickel, uranium and coal. Modern Australian mining is extremely well mechanized, some are even almost entirely mechanized, with one of the best applications of the newest technology in mining in the world. There are several institutes dedicated to studying and inventing new mining technology in Australia.

Australia is amongst the leading producer of lead in the world with China and USA leading. It produces 19% of the world’s new lead. Lead is relatively cheaper to mine and refine, as it’s found in larger quantities compared to other minerals. Some of this reserves are found in Queensland, Western Australia, the Northern Territory and South Australia (Mining-atlas.com, 2018).

Lead is the fourth most used metal worldwide, with a wide range of applications. Some of the applications include making car batteries, leaded gasoline, plumbing lines, roofing materials and white paint. Lead can be recycled indefinitely without losing its properties. The world’s supply of lead is increasing by around 2.3%, since other metallic elements eventually decay to lead (Lindbeck and Clark, 2010).

This report will focus on lead mining in Queensland. Specifically, the Mount Isa mines.

Lead

The symbol of lead is Pb with an atomic number 82 and 207.2 atomic weight. (this number is highest among all the elements, hence why it’s considered a heavy metal) its melting point is 601K, (874⁰C,622⁰F) and a boiling point of 2022K(2295⁰C,3179^OF) it has a density of 11.34g/cm³, which is denser than most metals (Williams, Holwell, Lilly, Case and McDonald, 2015). Lead is soft and malleable. When freshly cut, lead is shiny silver in color and tarnishes when exposed to air. The most important ore of lead is galena. This features of lead (high density melting point, ductility and relative inertness to oxygen), combined with its abundance and relatively low cost of production, makes lead in demand, in its various and extensive uses in construction, plumbing, batteries, bullets and shots, weights, white paints and leaded gasoline. One of the most current uses are making the glasses in computer screens to shield viewers from radiation (Wiliam, 2018).

How Mining Began

In 1883, Charles Rasp discovered lead ore by accident, when the wheel of a cart he was riding accidentally exposed some lead ore. In 1923, a silver-lead ore was discovered in Mount Isa, Queensland, Australia (Zhang and Chen, 2013). This are one of the richest mines in Australia. By John Campbell Miles. Production at Mount Isa still goes on since its production started in in the late 1940s.

Further expansion, by 3 companies including Mount Isa mines limited, has led to Mount Isa becoming one of the world’s largest mining, smelting, refining and recycling facilities   by 1960s. 

This map shows Australia’s major lead deposits and mines.

How Mining Began

Exploration took place from 1924, but production didn’t begin until May 1931.The early year of production were made difficult by the process of establishing the mines, including drilling, ore testing  and sinking the shafts, and skeptics over the discovery (The Conversation, 2018).

The cost of establishment was so high, that establishment was often behind schedule for months, bills went unpaid and structures had to be redone often, as shafts were flooding. The mount Isa operations struggled even after the first successful mining of the lead ore. The smelter was inadequate and additional blast furnaces and machines were required. In addition, the prices of metals were low during the great depression in 1932.

The First World War brought about a spike in demand for lead, and the Mount Isa mines had their fortunes turn for a short period. This struggle went on for a while, with fortunes turning from 1946-1973. Mining is still ongoing in mount Isa mines, now led by Glencore plc, formerly Xstrata plc (Manlapig, Drinkwater, Munro, Johnson and Watsford).

Companies Operating in the Mount Isa Mine

Mount Isa mine operates the Mount Isa lead mines as part of the Glencore group of companies.it has led to growth of many mining industry inventions, such as the Issamelt smelting technology and commercialized the Jameson cell column floatation technology. After the 1923 discovery of the silver-lead ore, in Queensland, Australia, Mount Isa mines was formed. Merging the initial 3 companies that were commissioned to start the mining explorations in 1923.in 1970, Mount Isa mines holdings took over,

 in 2003, Xstrata launched a successful takeover bid of the mines.it assumed 100% ownership of the mines from 2103 after merging with Glencore to form Glencore Xstrata plc.in 20^th may 2014 (Lindbeck and Clark, 2010).

Workforce of the Mount Isa Mine.

Companies Operating in the Mount Isa Mine

Historically, the original workers were slaves who were shipped from all over the world, including the United Kingdom. Some of the slave labor also came from the aborigines, who were kidnapped and forced to work in the mines.

Abolishment of the slave trade and establishment of workers’ rights unions ensured that mining companies, including Mount Isa Mines, gave their employees formal contracts and paid them accordingly.

The Mount Isa Mines are compelled by new laws to stop 100% fly-in fly-out workforces at the Australian mines. This laws seek to help reduce the negative impact of the mines to the environment. This will work by encouraging social responsibility of the mining companies by ensuring g minimum pollution since majority of their workers will be living in the areas surrounding the mines (Davis, 2004).

The workforce of the mount Isa mines consists of 11% women, and 89% men. These workers are given checkups at varying intervals to monitor the blood levels of lead to ensure that they’re within acceptable levels.

The Xstrata Company also conducts random air monitoring to control the amount of lead in the atmosphere. Some of the occupational positions at the mount Isa mines are rubber liners, workshops supervisors, mining trainees, waste dump operators, Paste plant operators, servicemen, quarry workers, excavator operators, contracts supervisors, heavy plant operators, light vehicle fitters, and mining engineers. The mount Isa mines gets some employees from the local community, although it has had a long history of workers flying in and flying out.

In recent years, there has been a slight decline in the number of workers being employed in the mining industry, due the health implications of lead mining, with increasing awareness of the dangers of lead mining. The decline has also been contributing d to by the increased specialized mechanizing of the mining with increasingly more sophisticated technology being put to use, requiring more specialized education.

Mining Methods Applied

Extraction of lead is from ores that are dug from underground mines, usually in conjunction with other minerals, like silver and zinc. At mount Isa, the layering the mining structure is 1000 meters. The ore bodies lie within 650-800m of the ground. Deep shafts are sunk into the ground to reach the ore, where it’s dug out, and loaded to a rail system to the surface for processing.

Some lead ore can be found near the surface and its mined using the open cast method.

Workforce of the Mount Isa Mine

Processing of Ore

The lead mine concentrator was built in 1966 using rod and ball milling, lead-silver flotation, zinc flotation and low-grade middling’s recovery circuits 2000 (Duncan, Buick, Kobayashi and Wilde, 2014). The plant in Isa was increased to 2.5 Mt/y in order to process more ore in mid=2000. The operations in Isa were improved.

Lead occurs in the ore form together with other minerals, usually zinc and silver. During processing, the lead ore is grounded into powder then passed through floatation process that mixes the lead ore with water. After that, it is pine oil is added and bubbles are introduced to form oil froth. It is then filtered to remove water the powder is the sintered at over 25000F to oxidize impurities such as Sulphur. the resulting mixture is further heated in a blast furnace with carbon, producing molten lead which is drawn into lead molds.at this stage the lead has achieved over 95% purity and this can be improved further by smelting and skimming impurities (Allen, 2011). Once the purity is sufficient the lead is cast into blocks as a finished product and some are taken to UK for refining.

Export of the lead

The main consumer of lead from Australia are China, Japan South Korea India and the United States (Valle de Souza, Dollery and Blackwell, 2018). Other leading importers of Australian lead are Korea, Singapore, New Zealand, Thailand and United Kingdom 

Variation in Demand

Lead was metal in very high demand in the ear of the Roman Empire, where it was used mainly for piping of hot water due to its resistance to corrosion and also in making coins. The demand for lead waned after the discovery of lead toxicity in the late 19^th century, but it picked up again during the World War 1, where it was used to make artillery, including armor, bomb shells and bullets.

The demand for lead was not as high in the World War 2 as in the World War 1.Mount Isa mines, despite recoding profits between 1946 and 1973, around 1957, production was curtailed due to fall in metal prices, with lead being one of the most affected. And the heavy capital expenditure due to the expansion in the existing operations.

Lead is a toxic metal that accumulates in animal bodies, leading to damage of the brain and nervous system, and permanently lowering IQ (Penrose, 1997). Discovery of lead poisoning in the late 19^th century led to the phasing out of use of lead in many applications. Use of lead in roofing materials, paints, and plumbing was subsequently banned.

Mining Methods Applied

Introduction of new laws for environmental production had also contributed to the decline of consumption of lead (Daley, Abdulla, Pretorius and Ungerer, 2018). However, consumption of lead has been on the rise in recent years, from the global automobile industries the electronic vehicle industry as lead is predominantly used in in manufacturing lead-acid batteries which is widely manufactured and consumed in automobiles. Lead production in the world is set to grow from 4.7Metric tones to around 5 Metric tons by 2020, representing a total yearly growth rate of about 2.1% (Manlapig et al., 1985). 

Impacts of Lead and Lead Mining

The main sources of lead getting into the ecosystem are atmospheric lead through vehicular emissions, paints, fertilizers, aerosols and pesticides (Forbes and Taylor, 2015). The ecosystem can also get exposed through lead acid batteries.

• Environmental impacts

Most lead concentrations are found in the natural environment due to human interference, such as in the application of lead in gasoline, putting the lead salts (chlorines, bromines and oxides) in the air (Orhan, Demirci and Yanmis, 2017). The heavy lead particles drops to the ground polluting the soils and river water with light particles being suspended in the air. Some of it falls back into the earth when it rains. This movements create an unnatural lead cycle. Pollution leads to poisoning and killing of animals on land and in water bodies, (interfering with bio functions of phytoplankton which are the most important source of oxygen in water) in cultivated soils, this lead is mixed to a depth in contact with the effective root zone, and this is readily absorbed by plants. This lead is stored in the plant foliage and may be consumed by herbivores and human, extending the chain of poison.

• Health effects

Lead effects on humans and animals.

Lead enters the human and animal bodies through consumption of food. It inhibits the bodies from synthesizing red blood cells, this in turn causes several damaging problems such as kidney damage, brain damage, nervous system damage, declined fertility in behavioral changes.

• Social

Communities living near the mining and smelting sites of lead are potentially at the highest risk of lead poisoning and are the ones who suffer the brunt of lead affects.

Opening of mining sites also causes displacement of people.

• Economic

Lead mining and production has a positive impact on the economy, with earnings made from the export of the ore and other finished products.

Real and Lasting Impacts of Lead Mining to the Mount Isa Area

Processing of Ore

The discovery of the lead ore in mount Isa area brought about positive development of the area. It brought about civilization and development of the area, establishment of modern facilities like railway systems, roads, schools, that benefitted the residents of these areas. Most of them also got employed in these mines and improved their standards of living (Sharma, 2010).

Processing of lead releases sulfur dioxide emissions which severely affects the air quality and the community health around the city. There has been large amounts of contamination of soils, water and air from these metals that has affected the surrounding environment enormously.

This led to ruining of the soils and water bodies, making the soils useless for agricultural production. There have been several cases of lead concentration in children 1-4 years old, about 11.3% of the test group (Butler and Leonardi, 2016). There was a general feeling that the Xstrata Company was not taking its social and environmental responsibility seriously of ensuring that the presence of lead in the environment (soil, air and water) is controlled as per regulation, although the company has denied this many times.

The people who live in this area have to live with some of the consequences of lead poisoning, like permanent nerve damage in some children (Ausimm.com.au, 2018). Some have taken the step further to sue the mining companies for the losses suffered due to lead poisoning. In September 2014, one of the Mount Isa residents won the rights to a case against Xstrata for allegedly causing nervous damages to her son through harmful emissions of lead (Lindbeck and Clark, 2010).

All this negative impacts of lead leave the community with a prolonged negative reaction to the companies, they may even hinder the progress of the company. 

Reference List

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Butler, J. and Leonardi, C. (2016). Improvement of squeezing ground prediction and monitoring capabilities for Mount Isa Mines Northern 3500 orebody. Mining Technology, 125(3), pp.142-155.

Daley, G., Abdulla, C., Pretorius, C. and Ungerer, J. (2018). Lead Toxicity: A Queensland Family Case Series. Pathology, 50, p.S15.

Davis, T. (2004). Mine-Scale Structural Controls on the Mount Isa Zn-Pb-Ag and Cu Orebodies. Economic Geology, 99(3), pp.543-559.

Duncan, R., Buick, I., Kobayashi, K. and Wilde, A. (2014). Chemical and stable isotopic characteristics of syn-tectonic tourmaline from the Western fold belt, Mount Isa inlier, Queensland, Australia. Chemical Geology, 381, pp.131-143.

Forbes, M. and Taylor, M. (2015). A review of environmental lead exposure and management in Mount Isa, Queensland. Reviews on Environmental Health, 30(3).

Lindbeck, K. and Clark, B. (2010). MINING PROJECT APPROVALS IN WESTERN AUSTRALIA. Journal American Society of Mining and Reclamation, 2010(1), pp.570-580.

Manlapig, E., Drinkwater, D., Munro, P., Johnson, N. and Watsford, R. (1985). Optimisation of Grinding Circuits at the Lead/Zinc Concentrator, Mount Isa Mines Limited. IFAC Proceedings Volumes, 18(6), pp.265-274.

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Orhan, F., Demirci, A. and Yanmis, D. (2017). CaCO3 and MgCO3 Dissolving Halophilic Bacteria. Geomicrobiology Journal, 34(9), pp.804-810.

Penrose, B. (1997). Occupational Lead Poisoning at Mount Isa Mines in the 1930s. Labour History, (73), p.123.

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Zhang, H. and Chen, Y. (2013). Study on the Mechanism of Backfill and Surrounding Rock of Open Stope during Subsequent Backfill Mining. Advanced Materials Research, 753-755, pp.452-456.