Materials, Minerals and Finite Resources
Australia exported $124 billion of iron ore in 2023, but Rio Tinto's Pilbara mines have only about 20 years of reserves left at current extraction rates.
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Q1 · Think about your phone, laptop, or a car, where do you think the metals and minerals inside them originally come from, and how might they be extracted?
Q2 · If a key mineral used in phone batteries became very rare and expensive, what do you think would happen to technology and society?
● Know
- Where materials come from (minerals, ores, living organisms)
- Why most materials are finite resources
- The stages of a material's lifecycle
● Understand
- Why recycling alone cannot solve resource depletion
- How lifecycle assessment gives a complete environmental picture
- Why reducing and reusing are preferred over recycling
● Can do
- Apply the waste hierarchy to material decisions
- Evaluate a sustainability claim using lifecycle evidence
- Identify trade-offs in material extraction and use
If you drive through Newman, Western Australia, you can watch hundred-metre-wide open pits being blasted open to reach haematite rock that is roughly 60% iron, it looks like rust-red rubble, yet this ore feeds every steel mill on Earth. Most metals are found in the Earth's crust combined with other elements as oresmineral compounds from which the metal can be extracted economically. Iron ore (haematite, Fe₂O₃) is crushed, then heated with coke in a blast furnace (smelting) to produce pig iron. Aluminium is extracted from bauxite ore using the Bayer process and then the Hall-Héroult electrolysis process. These extraction processes require enormous amounts of energy, smelting one tonne of aluminium uses about 15,000 kWh of electricity.
Materials are classified as renewable (can be regrown or regenerated on human timescales, timber, wool, cotton) or non-renewable (formed over millions of years and cannot be replaced, iron ore, coal, bauxite). Once a mineral ore deposit is mined out, it is gone forever. This scarcity drives recycling: it takes 95% less energy to recycle aluminium than to smelt it from ore, which is why aluminium recycling is economically valuable.
The Pilbara region of Western Australia contains the world's largest known iron ore deposits, over 50 billion tonnes of haematite. Rio Tinto and BHP operate 15 separate mine sites there, exporting about 900 million tonnes of ore per year, mostly to steel mills in China.
Australia is the world's largest exporter of iron ore, lithium, and bauxite. The NSW government manages mining licences under the Mining Act 1992, every mine site requires an environmental impact statement before ore extraction begins, because mining permanently alters the landscape.
A lifecycle assessment (LCA) tracks the total environmental impact of a material or product from extraction of raw materials, through manufacturing, transport, use, and finally disposal or recycling. The LCA asks: how much energy, water, and land does each stage consume? What pollutants are released? The full picture is often surprising, a cotton T-shirt uses about 2,700 litres of water to produce, far more than a polyester shirt, even though polyester comes from non-renewable petroleum.
LCA findings change engineering decisions. When companies discovered that manufacturing a lithium-ion battery releases more CO₂ than operating a petrol car for 2–3 years, they invested in renewable-powered battery factories. LCA also guides recycling priorities: aluminium has very high LCA benefit from recycling (95% energy saving); glass recycling saves only about 30% energy because melting glass is unavoidable. LCA makes environmental costs visiblethe first step to reducing them.
LCA of a steel bridge beam: iron ore mining (CO₂, land disturbance) → blast furnace smelting (large CO₂) → transport to fabricator → welding and coating (VOC emissions) → 50 years of use → demolition → 90% recycled as scrap steel. The recycling stage offsets roughly 40% of the total lifecycle emissions.
CSIRO's LCA research team in Canberra provides lifecycle data for Australian industries. Their work showed that Australian residential construction using lightweight steel framing has a 15% lower lifecycle carbon footprint than equivalent timber framing when accounting for harvesting, processing, and transport distances across the continent.
NSW manages waste using the waste hierarchy, a priority order for how society should deal with materials: (1) Avoid generating waste in the first place, (2) Reduce the amount used, (3) Reuse the item, (4) Recycle the material, (5) Recover energy, and (6) Dispose to landfill as a last resort. Each step down the hierarchy represents a greater loss of the material's embodied energy and value.
NSW has implemented several programs that apply the hierarchy to specific materials. The Return and Earn container deposit scheme (launched 2017) pays 10 cents per eligible container returned, a financial incentive that has recovered over 10 billion containers from landfill. The NSW single-use plastic bag ban reduced checkout bag use by over 80% in the first year. Industrial recycling programs target construction waste, in NSW, 70% of construction and demolition material is now diverted from landfill and recycled.
A 600 mL PET water bottle recycled via Return and Earn: consumer returns bottle (10c refund) → bale of PET flake collected → melted and extruded into polyester fibre → woven into a recycled polyester T-shirt. The recycled PET uses 70% less energy than making virgin PET from petroleum.
NSW's Return and Earn scheme has the highest container recovery rate in Australia, over 80% of eligible containers are returned. Revenue from the 10c deposits funds community programs across NSW, and the recovered material feeds directly back into Australian packaging manufacturers.
According to the waste hierarchy, the best option is to generating waste in the first place. The next steps are to the amount used, then reuse the item. After reuse comes , where the material itself is reprocessed. Disposal to is the last resort, representing the greatest loss of value. NSW's Return and Earn scheme pays per container, applying the hierarchy in practice.
At the start of this lesson, you heard that Australia exports $124 billion worth of iron ore per year, more than any other country, and that every tonne of steel on Earth came from ore dug out of the ground. But minerals are finite, and that raises a serious question about the future of the materials we depend on.
Now that you've worked through the lesson, how has your thinking shifted? Can you explain the difference between renewable and non-renewable resources, and suggest what might happen to steel production if iron ore deposits are exhausted without alternatives?
Q1. Explain the difference between a finite and a renewable resource. Give one example of each used in everyday products.
Q2. Using the waste hierarchy, evaluate three possible responses to the problem of old smartphone disposal. Rank them from most to least preferred and justify your ranking.
Q3. A company claims their product is 'environmentally friendly' because it uses recycled plastic. Evaluate this claim using lifecycle assessment thinking.