QCE Earth & Environmental Science · Unit 3 Topic 1: Use of non-renewable Earth resources
Ore deposits.
Most rock holds only a trace of any metal. An ore deposit is a place where natural processes have concentrated a metal enough for it to be mined at a profit. This lesson follows how that happens, how geologists find a deposit that is buried under hundreds of metres of younger rock, how it is mined, and what mining can leave behind.
Slide sideways to see the whole picture.
Illustration- 1Dense crystals settle in a magma chamber (screen 2)
- 2Hot fluids leave veins above a granite (screen 2)
- 3Weathering leaves bauxite behind (screen 3)
- 4Running water drops gold in a stream bed (screen 3)
- 5An ocean without oxygen lays down banded iron (screen 4)
- AOpen cut (screen 7)
- BUnderground (screen 7)
- CIn-situ leaching (screen 7)
Out of the ground
Geologists divide the things people use into two kinds: what is grown, and what is mined. Here is some of what is mined, in things you use every day, according to Geoscience Australia.
Iron, copper and aluminium, with traces of tungsten, silver, gold and cobalt, and of elements such as tantalum, niobium, germanium and rare earths. About 15 g of the phone is copper, and a little indium makes the touchscreen work.
Geoscience Australia: What makes a mineral critical? (2026) and Copper
An average family home contains more than 90 kg of copper: 40 kg of it in electrical wire and 30 kg in plumbing.
Geoscience Australia: Copper
Steel, made from iron ore, goes into car frames and engine cylinders, railway carriages and engines, ships, bridges and buildings.
Geoscience Australia: Iron
Mining in Australia is older than mining companies
Long before colonisation, First Nations people quarried stone and mined ochre, and traded them over hundreds of kilometres. Three places where they did, described by museums and heritage records:
Wilgie Mia
A red ochre mine. At the time of European contact its ochre was traded far and wide across Aboriginal Australia, and it is still used in ceremony today. Wilgie Mia is on the National Heritage List.
WA Museum
Wil-im-ee Moor-ring (Mount William)
Wurundjeri people quarried greenstone here to make blanks for stone hatchets, from 268 pits and shafts. The greenstone was traded up to 800 km away.
Australian Heritage Database; Museums Victoria
Bookatoo (Parachilna)
A red ochre mine whose ochre was famous over a wide region of Central Australia. Dieri people, who lived 500 km to the north, sent parties all that way to barter for it.
Museums Victoria
What we are learning
How natural processes concentrate metals into ore, how to identify ore minerals, how a buried deposit is found and mined, what mining can do to waterways, and how long Australia’s resources might last.
I can
- 1explain how gravity settling and hot fluids concentrate metals in and around a magma.
- 2explain how weathering, erosion and deposition concentrate ores such as bauxite and placer gold.
- 3explain how banded iron formations formed in an ocean without oxygen.
- 4identify ore minerals from their physical and chemical properties.
- 5explain how surveys and drilling find a buried deposit.
- 6explain how a deposit’s size, shape and depth decide how it is mined.
- 7describe how sulfide ores can harm waterways and the air, and how the harm is managed.
- 8use data to compare how much different lifestyles use, and to judge how long resources might last.
QCE Earth & Environmental Science, Unit 3 Topic 1: Use of non-renewable Earth resources. This lesson covers the topic’s metallic and non-metallic mineral resources. Coal, oil and gas are in a separate lesson.
How this lesson works: a jigsaw
- Home groups of three. Each of you takes one of the three expert screens.
- Expert groups (screens 2, 3 and 4). Work through your screen with the others who chose it, and fill in the teach-back card at the end.
- Back to your home group (screen 5). Teach your process to the other two. Then identify the ores and match eight real deposits to the processes that formed them, which takes all three experts.
- From discovery to closure (screens 6 to 9). Find a buried deposit, choose how to mine it, follow its footprint and judge how long the resource will last.
- Show what you know (screen 10). Eight questions.
Working on your own? Do every screen in order. Your answers and notes are saved in this browser, so you can stop and come back.
Ore from magma
Dense crystals settle to the floor of a magma chamber; hot fluids from a cooling granite leave veins in cracks.
Weathering and water
Rain leaves aluminium behind as bauxite; a stream drops gold where the water slows.
An ancient ocean
Iron dissolved in an ocean without oxygen settles as banded iron formation, the start of the Pilbara’s iron ore.
My notebook
Survey grid
Two pages: map buried metal objects with a metal detector, or a phone’s magnetometer, over a measured grid, then choose where to dig. It goes with the survey on screen 6.
AExpert group A
Ore from magma.
How can molten rock gather metals together?
In most magma, metals are spread thinly through the melt. Two processes can concentrate them: dense crystals or droplets sinking to the bottom of the magma, which is gravity settling, and hot, watery fluids carrying metals out of a cooling magma into cracks, which is hydrothermal activity.
Gravity settling needs a mineral, or a liquid, that is much denser than the magma around it, and enough time for it to sink before the magma sets solid. Hydrothermal fluids work differently: they do not depend on density, but on what a hot fluid can hold in solution and what it drops when it cools.
Key idea
Dense minerals can settle out of a magma into layers of ore. Hot fluids given off by a cooling magma can carry metals up into cracks, where they come out of the fluid as veins when it cools or reacts with the rock.
Why do magnetite crystals end up in a layer on the floor of a magma chamber?
Teach-back card: ore from magma
BExpert group B
Weathering and water.
How can rain and running water concentrate a metal?
At the surface, rain and running water break rock down and move the pieces. A metal can be concentrated in two ways: it can be left behind when the more mobile elements around it are dissolved and carried away, as aluminium is in bauxite, or it can be dropped by running water where the water slows, as gold is in a stream bed.
Australia is the world’s second-largest producer of bauxite, mined from open cuts at Weipa in Queensland, Gove in the Northern Territory and the Darling Range in Western Australia. Near Weipa, on western Cape York, economic bauxite deposits were found in 1955, and strip mining began in the early 1960s.
Gold that has weathered out of rock is heavier than almost everything else a creek carries, so it is trapped where the water slows: on the inside of bends, behind obstructions, and in hollows and cracks in the bedrock. Alluvial gold in creek gravels drew many of Queensland’s gold rushes. After gold was found near the Mary River at Gympie in 1867, “The alluvial gold deposits were mined within a year, so underground reserves were created to continue mining” (Queensland State Archives). The Palmer River field on Cape York Peninsula, where more than a thousand miners had arrived by 1874, “was initially a very rich alluvial field” (State Library of Queensland). Where younger sediments or lava flows later buried an old gold-bearing stream bed, miners called it a deep lead.
Waves sort grains in the same way. Mineral sands are old beach, river or dune sands rich in rutile, ilmenite, zircon and monazite, hard minerals that resist weathering, with densities of 4 to 5.5 g/cm³. The waves carried the lighter quartz grains back to sea and left the heavy minerals behind on the beach. In 2024 Australia produced more rutile than any other country. On Minjerribah, the Quandamooka people’s name for North Stradbroke Island, sand mining began in 1949, and the last mine, Enterprise, was due to stop in December 2019. Enterprise and Yarraman mainly produced mineral sands such as zircon, rutile and ilmenite (NASA Earth Observatory; Queensland Government).
Key idea
Weathering and water concentrate ore in two ways: by carrying away the more mobile elements and leaving the immobile ones behind, as in bauxite, and by dropping dense grains where the water slows, as in placer gold and mineral sands.
Specks of gold and grains of quartz sand of the same size are carried down a creek in a flood. As the water slows on the inside of a bend, which is dropped first, and why?
Teach-back card: weathering and water
CExpert group C
An ocean without oxygen.
Why did so much iron settle on the sea floor billions of years ago?
The Hamersley Group in the Pilbara is the most economically important set of rock layers in Australia, because of its large iron ore deposits. Its iron began as banded iron formation, laid down on the sea floor when the oceans held almost no oxygen: an anaerobic environment.
Turn a piece of banded iron formation
Red bands of jasper, a form of chert, alternate with shiny grey bands of iron oxide. The bands are often folded, because the rock was squeezed long after it formed.
Key idea
Iron can stay dissolved in seawater that has almost no oxygen. Where oxygen made by cyanobacteria met that water, the iron formed insoluble iron oxide, which settled in bands with silica. Much later, fluids removed silica and added iron, turning some banded iron formation into the high-grade ore mined in the Pilbara.
Why are banded iron formations like the Pilbara’s not forming in the oceans today?
Teach-back card: an ancient ocean
5Back in your home group
Identify the ores.
How can you tell one ore mineral from another?
Take turns to teach your expert process to your home group, using your teach-back card. Then test the twelve ore minerals on the bench, name six mystery ores, and decide which process concentrated each of eight real deposits.
Colour alone is a poor guide. Pyrite, chalcopyrite and gold are all yellow and metallic, but their streak and hardness tell them apart: gold leaves a golden-yellow streak and dents rather than breaks; chalcopyrite leaves a greenish-black streak and a steel nail scratches it; pyrite also leaves a dark streak, but a steel nail cannot scratch it.
Which process concentrated it?
0 of 8 sortedThis takes all three experts. Choose the process for each deposit.
Key idea
Streak, hardness, magnetism, density and a few special tests tell ore minerals apart, even ones that look alike. Each kind of deposit, and so each process, tends to concentrate particular minerals.
A brassy yellow, metallic mineral leaves a greenish-black streak. A fingernail cannot scratch it, but a steel nail can. What is it?
My notebook
6From discovery to closure · 1 of 4
Find it.
How do geologists find ore that is buried under hundreds of metres of rock?
An ore body changes the ground around it. It can make the rock denser, more magnetic or better at conducting electricity, and where it is near the surface, metals from it spread into the soil, water and plants above it, where geochemical sampling can detect them. Surveys measure these changes from the air or the ground. Only drilling shows whether the ore is really there.
Key idea
Magnetic, gravity and electromagnetic surveys detect how an ore body changes the physical properties of the rock; soil sampling detects how it changes the chemistry near the surface. Each survey narrows the search, and drilling tests it.
Ernest Henry, an iron oxide copper-gold deposit on the traditional lands of the Mitakoodi and Mayi peoples north-east of Cloncurry, was found the same way. It lies under 40 to 50 m of younger, flat-lying sediments. Magnetic surveys narrowed the search, and an electromagnetic survey on the ground then picked targets inside the magnetic highs. The first hole drilled into the deposit, in 1991, hit copper and gold at grades worth mining (Webb and Rowston, 1995; University of Queensland; Evolution Mining).
In 1975 Western Mining Corporation drilled where gravity and magnetic highs coincided, and found Olympic Dam. Why aim for the place where both highs lined up?
The electromagnetic anomaly drilled at Ernest Henry turned out to come from a layer near the top of the deposit, where weathering had concentrated copper. Most of the ore below it gave no electromagnetic anomaly at all. What does this show?
My notebook
7From discovery to closure · 2 of 4
Mine it.
How do a deposit’s size, shape and depth decide how it is mined?
Most metal ore is mined in one of three ways. Which one suits a deposit depends on how deep it is, how big it is and what shape it has, and on whether the ore can be dissolved where it lies.
Open cut
- A pit dug down from the surface in steps called benches.
- All the waste rock above and around the ore has to be dug out too.
- Suits big ore bodies at or near the surface, including low-grade ones.
Underground
- Shafts or sloping tunnels called declines reach the ore.
- The ore is broken and removed from spaces called stopes, and hoisted or trucked to the surface.
- Suits deep ore bodies, and narrow or rich ones, because far less waste rock is moved.
In-situ leaching
- A solution is pumped down wells, dissolves the ore minerals where they lie, and is pumped back up.
- No pit or tunnels, but the ore must be in rock that liquid can flow through, held between layers it cannot.
- Used for uranium in sand aquifers.
Choose the method
Three real depositsKey idea
Big ore bodies near the surface suit open cut. Deep, narrow or rich ones suit underground mining. Ore in a permeable aquifer between impermeable layers can be dissolved where it lies. Depth matters so much because the waste rock that a pit must remove grows far faster than the ore it reaches.
Using the pit model, why does an open pit become less likely to pay as the ore lies deeper?
My notebook
8From discovery to closure · 3 of 4
The footprint.
How can mining harm waterways and the air long after the ore is gone, and how is the harm managed?
Many metal ores are sulfide minerals, and they are often found with pyrite, an iron sulfide. When sulfides meet air and water, they make acid. At Mount Morgan and Mary Kathleen in Queensland, acid and metalliferous drainage from mines that closed decades ago still has to be managed.
How acid drainage starts
Put the chain in orderThe chemistry
Overall, pyrite reacts with oxygen and water to make orange iron(III) hydroxide and sulfuric acid:
4FeS₂ + 15O₂ + 14H₂O → 4Fe(OH)₃ + 8H₂SO₄
The reaction happens in several steps, and bacteria speed some of them up. Lime (calcium hydroxide or calcium oxide) neutralises the acid.
Mount Morgan
Gold and copper were mined here from 1882 until November 1990, and it was the largest gold mine in Queensland in the 19th and early 20th centuries. Mining left about 134 million tonnes of waste rock and tailings, and acid mine drainage on the site and downstream in the Dee River. The Queensland Government took over managing the mine’s legacy in January 1993. A water treatment plant doses the acid water from the open cut pit with lime, evaporators lower the water level in the pit so that it does not overflow, seepage from the waste rock dumps is caught and pumped back, and the water of the Dee River and the groundwater are sampled regularly.
Queensland Government: Mount Morgan remediation project; Fitzroy Partnership for River Health
Mary Kathleen
Uranium was mined from an open pit here in two campaigns. The mine was commissioned in 1956 and closed in 1963, then reopened in 1974, and it was considered mined out when mining stopped in 1982. The mine, mill, tailings dams and town were decommissioned from 1982 to 1985. Acid and metalliferous drainage from the pit and the tailings storage still causes poor-quality water and contaminated groundwater. The native title holders are the Kalkadoon People.
Queensland Government: Mary Kathleen remediation project
Queenstown
Copper ore was smelted at Mount Lyell from 1896 until the smelters closed in 1969. Trees felled for the smelters, sulfur fumes from smelting the sulfide ore, and fires stripped the surrounding hills, and erosion followed, leaving the bare hills the town is known for. Sulfur dioxide from smelting can also make rain acid.
Companion to Tasmanian History (UTAS); Encyclopaedia Britannica; Schneider and others (2022)
Key idea
Sulfide minerals exposed in waste rock and pit walls react with air and water to make acid, which dissolves metals and carries them into creeks and groundwater, harming the plants and animals that live there. Smelting sulfide ores gives off sulfur dioxide. Treating the water can take centuries, so mines now plan for it before they open.
Mining at Mount Morgan ended in 1990. Why does its water still need treatment today?
My notebook
9From discovery to closure · 4 of 4
How long will it last?
Are Australia’s mineral resources sustainable, and who uses them?
Ore deposits formed over geological time, so they are not replaced on any human timescale. How long they last depends on how much ore is known, how fast it is mined, and how much people use.
Different lifestyles, different footprints
Tonnes per personShow the numbers as a table
A material footprint counts all raw materials, including crops, timber and fossil fuels as well as metal ores and other minerals, and gives them to the region whose people use the final products. The chart shows the UN’s figures for regions. Australia’s own estimate for 2024 is about 31.1 tonnes per person (Australian Bureau of Statistics, from a different dataset).
Years of supply
Geoscience Australia, 2025Geoscience Australia divides the resources that are known and accessible for mining by one year’s production. The answer is the resource life: how many years the resources would last at that rate.
Show the numbers as a table
Work it out
Divide resources by production“It is not possible to state with any certainty how long Australian, and world, resources will last”, Geoscience Australia says, because production rates vary, deposits can become economic or uneconomic, and new resources are rarely found at the same rate as old ones are used up. Its resource life figures are a snapshot in time, for general impressions only.Geoscience Australia, Australia’s Identified Mineral Resources 2025: Summary of reserve and resource life
Key idea
Mineral resources are non-renewable. Resource life compares what is known with what is mined, but it changes as prices, technology, discoveries and demand change. People in wealthy regions use several times as much material as the world average, so how resources are used is as much a part of sustainability as how many are left.
Geoscience Australia gives Australia’s copper a resource life of 145 years. What does that number tell you?
My notebook
10Show what you know
Show what you know.
Eight questions, one for each of the I can statements on screen 1. You get one try at each, so think before you tap.
Which pair of processes can concentrate metals in and around a magma?
Why is bauxite at Weipa, Gove and the Darling Range rich in aluminium?
What did oxygen from cyanobacteria do in the making of banded iron formation?
A black, metallic mineral leaves a black streak, and a hand magnet snaps onto it. What is it?
Which result would point best to a dense, magnetic ore body buried under 300 m of younger rock?
Uranium lies in loose sand that holds groundwater, between two clay layers, about 110 m down. Which method suits it, and why?
Which statement about acid and metalliferous drainage is correct?
Australia’s resource life for bauxite is 40 years, and the world’s is 65. Which conclusion is best supported?
Survey grid
Map buried metal objects with a metal detector, or a phone’s magnetometer, over a measured grid, then decide where to dig and evaluate your survey.
For teachers
Curriculum
Queensland Curriculum and Assessment Authority (QCAA), Earth & Environmental Science 2025 v1.0 General senior syllabus (January 2024), Unit 3: Living on Earth, Topic 1: Use of non-renewable Earth resources (22 hours). The syllabus is © State of Queensland (QCAA) 2024, licensed under CC BY 4.0. Its Science understanding subject matter for the topic, which can be assessed in the external examination, is:
Formation and location of non-renewable mineral and energy resources
- Explain the differences between metallic, non-metallic and energy resources.
- Describe non-renewable resources as those that are typically replenished at timescales of centuries to millennia, including
- metallic resources (gold and iron ore)
- non-metallic (mineral sands)
- fossil fuels (coal, coal seam gas, crude oil and natural gas).
- Interpret information relating to
- metallic formation including banded iron formations and hydrothermal and alluvial gold formations
- non-metallic formation (mineral sands) including alluvial and placer deposits
- fossil fuel formation (coal seams and stratigraphic traps).
Exploration of mineral and energy resources
- Explain how mineral and energy resources are discovered using a variety of techniques to identify the location, spatial extent of the deposit and quality of the resource, including
- literature and historic records
- remote sensing techniques, including satellite and aerial imaging, hyperspectral imaging, and geophysical datasets for magnetic and gravitational
- direct sampling geochemical techniques, including soil, rock sampling, auguring, drilling and core sampling.
- Interpret geophysical and geochemical data to predict the presence of a resource, e.g.
- remote sensing (magnetic imaging to detect iron ore)
- density (bore hole logging).
Extraction, separation and processing of mineral and energy resources
- Explain how a feasibility study is conducted to determine whether the resource can be extracted effectively and profitably, which includes analysis of the
- size and value (market value and associated economic factors) of the resource
- suitable extraction methods
- refining processes of the commodity
- environmental impacts
- rehabilitation plan
- other key parameters such as availability of
- support facilities and infrastructure
- site access
- social impacts (land rights, employment, health).
- Analyse how the type, volume and location of mineral and energy resources influences the methods of extraction, including
- for coal, gold and iron ore
- open-cut mining
- underground mining (stoping, room and pillar, also known as bord and pillar)
- for mineral sands
- dredging
- open-cut mining
- for coal seam gas, oil and natural gas
- onshore and offshore drilling
- fracking.
- Determine the appropriate method of extraction (e.g. sluicing, froth flotation, gravitational separation, smelting) by analysing the physical and chemical properties of
- metallic resources: gold and iron ore
- non-metallic resources: mineral sands.
- Explain how the method of extraction, processing and separation is determined by the physical and chemical properties of these metallic and non-metallic resources.
Environmental monitoring and management
- Describe how resource extraction can affect the atmosphere, hydrosphere and biosphere.
- Explain how common environmental factors are monitored to minimise environmental impacts on
- air quality, e.g. ozone, SO2, CO, visibility, fine particles PM10
- water quality, e.g. pH, dissolved oxygen, turbidity, BOD
- soil quality, e.g. pH, erosion, changes in soil structure
- distribution and abundance of organisms, e.g. line transects, Lincoln index
- noise pollution, e.g. sound level meters, sleep patterns.
- Interpret data from environmental monitoring, including distribution and abundance surveys, air quality, water quality.
- Interpret data relating to the effectiveness of environmental monitoring strategies.
- Interpret data about the effectiveness of turbidity management strategies, using settling ponds.
The syllabus prints three of these points with a dash, shown here as a comma or a colon.
This lesson covers the topic’s metallic and non-metallic resources. Coal, oil and gas are in the Coal, oil and gas lesson. Where this lesson covers the subject matter:
- Metallic, non-metallic and energy resources: screen 1 (metals in everyday things) and screen 3 (mineral sands, a non-metallic resource). The lesson does not set out the three kinds side by side, so make the comparison explicit.
- Non-renewable resources: screen 9 (Geoscience Australia’s resource life for gold, iron ore and other metals, and for zircon, a mineral sand). Fossil fuels are in the Coal, oil and gas lesson.
- Formation: screen 2 (hydrothermal veins and gravity settling), screen 3 (alluvial gold, the Gympie and Palmer River goldfields, and mineral sands as placer deposits), screen 4 (banded iron formation) and screen 5 (identifying ores; matching deposits, including gold in quartz veins, to the processes that formed them).
- Exploration: screen 6 (magnetic, gravity and electromagnetic surveys, soil sampling and drilling, in a model and at Ernest Henry) and the printable survey grid, which give practice in interpreting geophysical and geochemical data.
- Extraction methods: screen 7 (open-cut and underground mining, including stoping, at Ernest Henry, the Super Pit and Honeymoon, and the pit model showing why depth decides). Honeymoon’s in-situ leaching goes beyond the syllabus.
- How extraction affects the hydrosphere, biosphere and atmosphere: screen 8 (acid and metalliferous drainage at Mount Morgan and Mary Kathleen, the creek model, and sulfur dioxide from smelting at Queenstown).
The lesson does not cover literature and historic records, satellite, aerial and hyperspectral imaging, rock sampling, augering and core sampling, bore hole density logging, feasibility studies, room and pillar mining, dredging, choosing separation and processing methods (sluicing, froth flotation, gravity separation, smelting), how air, water, soil, organisms and noise are monitored, interpreting monitoring data, or turbidity management with settling ponds. Teach these alongside it.
Of the Science as a human endeavour points, screen 6 shows how surveys from the air and on the ground narrow the search before anyone drills, and screen 8 shows a mine site that the state took over after mining ended, with its water monitored and treated. The lesson does not cover licensing and permissions, carbon pricing, or Environmental Impact Assessments and trigger values; the Coal, oil and gas lesson covers coal seam gas and groundwater, but not economic risk. Of the Science inquiry points, the survey maps on screen 6 and the printable survey grid give practice in investigating exploration datasets to predict where a resource is. The others (modelling separation and processing, slope revegetation and erosion, quadrat or transect surveys, evaporation, and settling ponds) need practical work.
Units 3 and 4 are studied as a pair. Schools set three internal assessments across them, a data test (10%), a student experiment (20%) and a research investigation (20%), and the Science understanding subject matter can also be assessed in the external examination (50%). The survey maps, the resource life data and the survey grid give practice for the data test, and the survey grid can be extended into a student experiment.
How the lesson is taught
The lesson is built as a jigsaw (Aronson and Patnoe, 2011). Each student in a home group of three becomes the group’s expert on one way ore forms, and the home group can only finish screen 5 by pooling all three. The jigsaw makes every student responsible for teaching part of the content, which suits a topic with several parallel processes.
- Lesson 1: screen 1 together; form home groups and give out the expert screens.
- Lesson 2: expert groups work through screens 2, 3 or 4 and complete their teach-back cards (about 35 minutes), then rehearse their explanation with their expert group.
- Lesson 3: home groups teach back (about 5 minutes each), then screen 5: the bench, the mystery ores and the deposit sort. With a school ore kit, use the real tests alongside the 3D specimens.
- Lessons 4 and 5: screens 6 and 7, then the printable survey grid as a practical outside.
- Lesson 6: screens 8, 9 and 10.
Students working alone can do every screen in order. The teach-back cards then serve as a summary of each process.
Handle with care
- Mining is many students’ families’ work in Queensland, in places such as Mount Isa, Cloncurry and Weipa, and uranium mining in particular is contested. The lesson sets out what the sources say about impacts and their management without telling students what to think about mining. Let students bring their own knowledge.
- First Nations material on screen 1 uses only what museums and heritage records have published. Some knowledge about ochre mines is restricted, so the lesson gives only the public record: the Country, what was mined, and how far it was traded. To go further, invite local Traditional Owners, following your school’s protocols. The traditional owners at Ernest Henry are named as Evolution Mining names them, and the native title holders at Mary Kathleen as the Queensland Government names them.
- Safety: hydrochloric acid tests are for the teacher to demonstrate. Do not test sphalerite with acid: it gives off hydrogen sulfide. Radioactive minerals such as uraninite should not be handled in class. For the survey grid, do not dig in school grounds unless the location of buried services has been checked; hiding objects under a sheet or in a sand pit avoids the need.
Misconceptions the screens target
- Ore is rock made mostly of metal (screen 1). Ore is any rock that can be mined at a profit, and many ores contain only a small percentage of metal.
- Heavy minerals are magnetic, or magnetism moves crystals in magma (screens 2 and 5). Density does the sorting; magnetite is one of very few strongly magnetic minerals.
- Gold is always found as nuggets (screens 3 and 5). Most placer gold is fine specks and flakes, trapped where water slows.
- All yellow metallic minerals are gold (screen 5). Streak and hardness tell gold, pyrite and chalcopyrite apart.
- A survey finds ore (screen 6). Surveys find differences in the rock; only drilling confirms ore.
- Open cut is always cheaper (screen 7). The waste rock grows much faster than the ore as depth increases.
- In-situ leaching has no effect on groundwater (screen 7). It depends on the confining clay layers; at Honeymoon, a 1999 trial found leach solution had moved through a gap in the lower clay layer (Mudd, 2002).
- Pollution stops when a mine closes (screen 8). Acid drainage continues for as long as the sulfides react.
- Resource life is a countdown (screen 9). It is a snapshot that assumes nothing changes.
About the data and the pictures
- All the cross-sections, the stream, the survey area and the pit are models, not surveys of real places. Each says what is stretched or simplified. The 3D specimens are drawn in code from mineral descriptions, not photographed.
- Gravity settling: chromite layers of the Bushveld Complex as the best-studied example, and their disputed origin: USGS Scientific Investigations Report 2010-5070-E; Holness and others (2023), for settling; University of the Witwatersrand (2022), against. Kambalda: Frost (1992), UWA.
- Hydrothermal deposits: Geoscience Australia, Gold and Tin mineral facts.
- Bauxite: Geoscience Australia, Aluminium mineral facts; Weipa Town Authority, Western Cape History (economic deposits found in 1955); Queensland Places, Weipa (strip mining from the early 1960s); production rank: Geoscience Australia, AIMR 2025 world rankings (2024 data).
- Placers and mineral sands: Yukon Geological Survey (2011); Geoscience Australia, Gold, Tin and Mineral sands; Queensland State Archives, Gold at Gympie (2021); State Library of Queensland, Palmer River Goldfield (2013) and James Venture Mulligan (2019; more than a thousand miners on the field by 1874); State Library Victoria (Ballarat and Bendigo, in the deposit sort); rutile rank: AIMR 2025; Minjerribah: Queensland Government ministerial statement, 12 December 2019 (mining since 1949; the decommissioning of Enterprise Mine) and NASA Earth Observatory (2020; Enterprise due to stop in December 2019; what Enterprise and Yarraman produced).
- Banded iron formation: Geoscience Australia, Iron; Australian Museum; WA Museum; Geological Survey of WA (Hamersley Group, 2630 to 2445 million years); University of Colorado (2024); Courtney-Davies and others (2024), PNAS (ore bodies 1.4 to 1.1 billion years old).
- Mineral properties: Handbook of Mineralogy (Mineralogical Society of America); gibbsite density for bauxite; gold streak: geology.com; acid tests: Missouri University of Science and Technology (malachite), Athabasca University (sphalerite); gold hardness: Geoscience Australia.
- Olympic Dam, the basis of the survey model, the first check on screen 6 and the explanation of the check on screen 7: Esdale and others, geophysical case history (ASEG; 1975 discovery, 260 m of cover at the deposit, 17 mGal and 1600 nT anomalies); SA Department for Energy and Mining (about 300 m of cover; host); BHP Draft EIS 2009, chapters 2 and 5 (the proposed pit and its 300 to 350 m of pre-strip). Pyrite on the specimen bench: SA Department for Energy and Mining, Brukunga mine site (mined for the sulfur to make sulfuric acid).
- Ernest Henry: Webb and Rowston (1995) (magnetic, then electromagnetic surveys; 40 to 50 m of cover; the first hole; the electromagnetic target was a weathered, copper-rich layer and most of the primary ore gave no anomaly); University of Queensland, Northwest Mineral Province Deposit Atlas (discovered in October 1991; open pit 1997 to 2011, underground since 2011; about 1,000 m deep); Evolution Mining, Ernest Henry fact sheet (iron oxide copper-gold deposit; sublevel caving; traditional lands of the Mitakoodi and Mayi peoples); McGrath and others (2014) (the sublevel cave below the old pit, and the pit’s unstable south wall). Sources differ on the pit’s final depth (650 m, University of Queensland; a planned 570 m, Mining Technology) and on the distance from Cloncurry (about 30 km, Webb and Rowston; 38 km, Evolution Mining).
- Super Pit: Northern Star Resources (1903 mines and workings; 1989); EPA WA referral for Fimiston South (2022) and EPA Report 1779 (pit size; the pits joined).
- Honeymoon: SA Department for Energy and Mining; MESA Journal (depth, basal sand, clay layers); AusIMM (Yarramba Palaeochannel); Boss Energy ASX release, 22 April 2024; Mudd (2002).
- Mount Morgan: Queensland Government, Mount Morgan remediation project (mining from 1882 to November 1990; the largest gold mine in Queensland; 134 million tonnes of waste rock and tailings; the state took over the legacy in January 1993; acid mine drainage on site and in the Dee River; the risk of the pit overtopping; the lime-dosing plant; evaporation, seepage interception and pump-back; sampling down the Dee River); Fitzroy Partnership for River Health, acid mine drainage fact sheet (pyrite; seepage interception from the waste rock dumps; evaporators to lower the pit water level); CQUniversity (2007), the Dee River study used in the creek model. Mary Kathleen: Queensland Government, Mary Kathleen remediation project. Treatment timelines in the creek model: Scott and others (2011, Brukunga, 300 to more than 1,000 years). Queenstown: Companion to Tasmanian History; Britannica; Schneider and others (2022). Some sources give 1970 for the end of smelting at Mount Lyell.
- Material footprint: UN SDG Global Database, series EN_MAT_FTPRPC, 2022 values. Resource life: Geoscience Australia, AIMR 2025, Tables 3 and 6 (resources as at December 2024; production for 2024). GA divides accessible economic demonstrated resources by production and rounds to the nearest five years.
Answers at a glance
- Mystery ores: 1 galena, 2 pyrite, 3 magnetite, 4 chalcopyrite, 5 haematite, 6 malachite.
- Deposit sort: Kambalda nickel, settling; gold in quartz veins, hot fluids; Ballarat and Bendigo creek gold, weathering and running water; Weipa, Gove and Darling Range bauxite, weathering and running water; Hamersley iron ore, ancient ocean; tin around granites, hot fluids; beach mineral sands, weathering and running water; Bushveld chromite, settling.
- Survey: drilling finds ore in cells M6 to O8, L7 and P7, under the overlap of the gravity and magnetic highs; the cells around them show altered granite, a sign that ore is close. The magnetic dyke runs from the south-west corner towards the north (columns C to J); the dense gabbro is around E4.
- Mining: Ernest Henry, underground; Super Pit, open cut; Honeymoon, in-situ leaching.
- Acid drainage chain: mining exposes pyrite; air and water react with it; sulfuric acid and dissolved iron form; the acid dissolves metals; the metal-rich acid water reaches the creek.
- Resource life by hand: copper 108.02 ÷ 0.75 = 144.0 (GA: 145); gold 12,938 ÷ 284 = 45.6 (GA: 45); bauxite 3,969 ÷ 100.5 = 39.5 (GA: 40).
- Checks: q-magma, denser than the melt; q-water, the gold; q-ocean, the oceans now contain oxygen; q-ores, chalcopyrite; q-find, other rocks cause one high but not both; q-eh, a survey shows where the rock is different and only drilling shows why; q-mine, the pit widens as it deepens; q-foot, pyrite keeps reacting; q-last, at the 2024 rate, if nothing else changed.
- Exit check: x1 settling and hot fluids; x2 high rainfall leached the mobile elements; x3 insoluble iron oxide; x4 magnetite; x5 gravity and magnetic highs together; x6 in-situ leaching; x7 keeps forming while sulfides meet air and water; x8 less long than the world’s at current rates.
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References
- Aronson, E., & Patnoe, S. (2011). Cooperation in the classroom: The jigsaw method (3rd ed.). Pinter & Martin.
- Courtney-Davies, L., and others (2024). A billion-year shift in the formation of Earth’s largest ore deposits. Proceedings of the National Academy of Sciences.
- McGrath, A. T., Campbell, A. D., & Tucker, J. B. (2014). Transition of the Ernest Henry Mine from open pit to an underground sublevel cave. 12th AusIMM Underground Operators’ Conference, 297–308.
- Mudd, G. M. (2002). Uranium mining in Australia: Environmental impact, radiation releases and rehabilitation. Proceedings of the International Mine Water Association Symposium 2002, 49–58.
- Scott, P., and others (2011). Brukunga mine site. Mine Closure 2011, Australian Centre for Geomechanics.
- Webb, M., & Rowston, P. (1995). The geophysics of the Ernest Henry Cu-Au deposit (N.W.) Qld. Exploration Geophysics, 26(3), 51–59.
Sources
- QCAA: Earth & Environmental Science 2025 v1.0 General senior syllabus
- Geoscience Australia: What makes a mineral critical?; mineral facts for copper, iron, aluminium, gold, tin and mineral sands
- Geoscience Australia: AIMR 2025, reserve and resource life, Table 3 and world rankings
- UN SDG Global Database: indicator 12.2.1, material footprint; ABS: Circular economy
- WA Museum: Tales of the Weld Range; Mount William Stone Hatchet Quarry: heritage nomination; Museums Victoria: Wil-im-ee Moor-ring greenstone and Bookatoo red ochre
- USGS: Stratiform chromite deposit model; University of the Witwatersrand: Bushveld Complex; Holness and others (2023); Frost (1992)
- Geological Survey of WA: Fortescue and Hamersley basins; Australian Museum: Banded iron formation; University of Colorado (2024)
- Weipa Town Authority: Western Cape History; Queensland Places: Weipa; Queensland State Archives: Gold at Gympie; State Library of Queensland: Palmer River Goldfield and James Venture Mulligan; Queensland Government (2019): Minjerribah; NASA Earth Observatory: Saving Straddie’s Sand
- Yukon Geological Survey: Placer deposits; Handbook of Mineralogy
- Olympic Dam: a geophysical case history (ASEG); SA DEM: Olympic Dam
- Webb and Rowston (1995): The geophysics of the Ernest Henry Cu-Au deposit; University of Queensland: Northwest Mineral Province Deposit Atlas, Ernest Henry; Evolution Mining: Ernest Henry fact sheet
- Northern Star: KCGM operations; EPA WA Report 1779
- SA DEM: Honeymoon uranium mine; MESA Journal: Honeymoon; Mudd (2002)
- Queensland Government: Mount Morgan remediation project; Fitzroy Partnership for River Health: acid mine drainage fact sheet; CQUniversity (2007): the Dee River; SA DEM: Brukunga mine site; Queensland Government: Mary Kathleen remediation project; Companion to Tasmanian History: Queenstown